Crystallization: The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)X-Ray Diffraction: The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Crystallography: The branch of science that deals with the geometric description of crystals and their internal arrangement. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Selenomethionine: Diagnostic aid in pancreas function determination.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Synchrotrons: Devices for accelerating protons or electrons in closed orbits where the accelerating voltage and magnetic field strength varies (the accelerating voltage is held constant for electrons) in order to keep the orbit radius constant.Bacterial Proteins: Proteins found in any species of bacterium.Calcium Oxalate: The calcium salt of oxalic acid, occurring in the urine as crystals and in certain calculi.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Hemoglobin C: A commonly occurring abnormal hemoglobin in which lysine replaces a glutamic acid residue at the sixth position of the beta chains. It results in reduced plasticity of erythrocytes.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Muramidase: A basic enzyme that is present in saliva, tears, egg white, and many animal fluids. It functions as an antibacterial agent. The enzyme catalyzes the hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrin. EC 3.2.1.17.Pyrococcus horikoshii: Anaerobic hyperthermophilic species of ARCHAEA, isolated from hydrothermal fluid samples. It is obligately heterotrophic with coccoid cells that require TRYPTOPHAN for growth.Volatilization: A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.Detergents: Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.Solubility: The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Solutions: The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Thermus thermophilus: A species of gram-negative, aerobic, rod-shaped bacteria found in hot springs of neutral to alkaline pH, as well as in hot-water heaters.Calcium Carbonate: Carbonic acid calcium salt (CaCO3). An odorless, tasteless powder or crystal that occurs in nature. It is used therapeutically as a phosphate buffer in hemodialysis patients and as a calcium supplement.Archaeal Proteins: Proteins found in any species of archaeon.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Differential Thermal Analysis: Technique by which phase transitions of chemical reactions can be followed by observation of the heat absorbed or liberated.Chemical Precipitation: The formation of a solid in a solution as a result of a chemical reaction or the aggregation of soluble substances into complexes large enough to fall out of solution.Polyethylene Glycols: Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.Urinary Calculi: Low-density crystals or stones in any part of the URINARY TRACT. Their chemical compositions often include CALCIUM OXALATE, magnesium ammonium phosphate (struvite), CYSTINE, or URIC ACID.Archaeoglobus fulgidus: A species of extremely thermophilic, sulfur-reducing archaea. It grows at a maximum temperature of 95 degrees C. in marine or deep-sea geothermal areas.Kidney Calculi: Stones in the KIDNEY, usually formed in the urine-collecting area of the kidney (KIDNEY PELVIS). Their sizes vary and most contains CALCIUM OXALATE.Chromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.Methanococcaceae: A family of anaerobic METHANOCOCCALES whose organisms are motile by means of flagella. These methanogens use carbon dioxide as an electron acceptor.Aldose-Ketose Isomerases: Enzymes that catalyze the interconversion of aldose and ketose compounds.Scattering, Radiation: The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Protein Structure, Quaternary: The characteristic 3-dimensional shape and arrangement of multimeric proteins (aggregates of more than one polypeptide chain).Bothrops: A genus of poisonous snakes of the VIPERIDAE family. About 50 species are known and all are found in tropical America and southern South America. Bothrops atrox is the fer-de-lance and B. jararaca is the jararaca. (Goin, Goin, and Zug, Introduction to Herpetology, 3d ed, p336)Negative Staining: The technique of washing tissue specimens with a concentrated solution of a heavy metal salt and letting it dry. The specimen will be covered with a very thin layer of the metal salt, being excluded in areas where an adsorbed macromolecule is present. The macromolecules allow electrons from the beam of an electron microscope to pass much more readily than the heavy metal; thus, a reversed or negative image of the molecule is created.Diffusion: The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.United States National Aeronautics and Space Administration: An independent Federal agency established in 1958. It conducts research for the solution of problems of flight within and outside the Earth's atmosphere and develops, constructs, tests, and operates aeronautical and space vehicles. (From U.S. Government Manual, 1993)Taxes: Governmental levies on property, inheritance, gifts, etc.Metals: Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant & Hackh's Chemical Dictionary, 5th ed)Euthanasia, Passive: Failing to prevent death from natural causes, for reasons of mercy by the withdrawal or withholding of life-prolonging treatment.History, 20th Century: Time period from 1901 through 2000 of the common era.Computer Graphics: The process of pictorial communication, between human and computers, in which the computer input and output have the form of charts, drawings, or other appropriate pictorial representation.Propiolactone: Disinfectant used in vapor form to sterilize vaccines, grafts, etc. The vapor is very irritating and the liquid form is carcinogenic.Time-Lapse Imaging: Recording serial images of a process at regular intervals spaced out over a longer period of time than the time in which the recordings will be played back.Receptor, Cannabinoid, CB1: A subclass of cannabinoid receptor found primarily on central and peripheral NEURONS where it may play a role modulating NEUROTRANSMITTER release.DelawarePolypropylenes: Propylene or propene polymers. Thermoplastics that can be extruded into fibers, films or solid forms. They are used as a copolymer in plastics, especially polyethylene. The fibers are used for fabrics, filters and surgical sutures.Polymers: Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Dictionaries, MedicalDictionaries as Topic: Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.Physics: The study of those aspects of energy and matter in terms of elementary principles and laws. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Dictionaries, ChemicalFructose: A monosaccharide in sweet fruits and honey that is soluble in water, alcohol, or ether. It is used as a preservative and an intravenous infusion in parenteral feeding.Anhydrides: Chemical compounds derived from acids by the elimination of a molecule of water.Silicon: A trace element that constitutes about 27.6% of the earth's crust in the form of SILICON DIOXIDE. It does not occur free in nature. Silicon has the atomic symbol Si, atomic number 14, and atomic weight [28.084; 28.086].Semiconductors: Materials that have a limited and usually variable electrical conductivity. They are particularly useful for the production of solid-state electronic devices.Nanostructures: Materials which have structured components with at least one dimension in the range of 1 to 100 nanometers. These include NANOCOMPOSITES; NANOPARTICLES; NANOTUBES; and NANOWIRES.Transistors, Electronic: Electrical devices that are composed of semiconductor material, with at least three connections to an external electronic circuit. They are used to amplify electrical signals, detect signals, or as switches.BooksAnniversaries and Special Events: Occasions to commemorate an event or occasions designated for a specific purpose.History, 21st Century: Time period from 2001 through 2100 of the common era.Sapindaceae: The soapberry plant family of the order Sapindales, subclass Rosidae, class Magnoliopsida. Some members contain SAPONINS.Nanotechnology: The development and use of techniques to study physical phenomena and construct structures in the nanoscale size range or smaller.Access to Information: Individual's rights to obtain and use information collected or generated by others.Antarctic Regions: The continent lying around the South Pole and the southern waters of the Atlantic, Pacific, and Indian Oceans. It includes the Falkland Islands Dependencies. (From Webster's New Geographical Dictionary, 1988, p55)Volcanic Eruptions: The ash, dust, gases, and lava released by volcanic explosion. The gases are volatile matter composed principally of about 90% water vapor, and carbon dioxide, sulfur dioxide, hydrogen, carbon monoxide, and nitrogen. The ash or dust is pyroclastic ejecta and lava is molten extrusive material consisting mainly of magnesium silicate. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Staphylococcus saprophyticus: A species of gram-positive bacteria in the family STAPHYLOCOCCACEAE. It commonly causes urinary tract infections in humans.Pituitary Hormones, Posterior: Hormones released from the neurohypophysis (PITUITARY GLAND, POSTERIOR). They include a number of peptides which are formed in the NEURONS in the HYPOTHALAMUS, bound to NEUROPHYSINS, and stored in the nerve terminals in the posterior pituitary. Upon stimulation, these peptides are released into the hypophysial portal vessel blood.Newspapers: Publications printed and distributed daily, weekly, or at some other regular and usually short interval, containing news, articles of opinion (as editorials and letters), features, advertising, and announcements of current interest. (Webster's 3d ed)Hematoporphyrins: Iron-free derivatives of heme with 4 methyl groups, 2 hydroxyethyl groups and 2 propionic acid groups attached to the pyrrole rings. Some of these PHOTOSENSITIZING AGENTS are used in the PHOTOTHERAPY of malignant NEOPLASMS.Hematoporphyrin Derivative: A complex mixture of monomeric and aggregated porphyrins used in the photodynamic therapy of tumors (HEMATOPORPHYRIN PHOTORADIATION). A purified component of this mixture is known as DIHEMATOPORPHYRIN ETHER.Seals, Earless: The family Phocidae, suborder PINNIPEDIA, order CARNIVORA, comprising the true seals. They lack external ears and are unable to use their hind flippers to walk. It includes over 18 species including the harp seal, probably the best known seal species in the world.ThiophenesHoney: A sweet viscous liquid food, produced in the honey sacs of various bees from nectar collected from flowers. The nectar is ripened into honey by inversion of its sucrose sugar into fructose and glucose. It is somewhat acidic and has mild antiseptic properties, being sometimes used in the treatment of burns and lacerations.Bees: Insect members of the superfamily Apoidea, found almost everywhere, particularly on flowers. About 3500 species occur in North America. They differ from most WASPS in that their young are fed honey and pollen rather than animal food.Apitherapy: The medical use of honey bee products such as BEE VENOM; HONEY; bee pollen; PROPOLIS; and royal jelly.Leptospermum: A plant genus of the family MYRTACEAE. The common name of tea tree is also used for MELALEUCA and KUNZEA.Carbonates: Salts or ions of the theoretical carbonic acid, containing the radical CO2(3-). Carbonates are readily decomposed by acids. The carbonates of the alkali metals are water-soluble; all others are insoluble. (From Grant & Hackh's Chemical Dictionary, 5th ed)Halorubrum: A genus of HALOBACTERIACEAE which are chemoorganotrophic and strictly aerobic. They have been isolated from multiple hypersaline environments that vary widely in chemical and physical properties.Halobacteriaceae: A family of extremely halophilic archaea found in environments with high salt concentrations, such as salt lakes, evaporated brines, or salted fish. Halobacteriaceae are either obligate aerobes or facultative anaerobes and are divided into at least twenty-six genera including: HALOARCULA; HALOBACTERIUM; HALOCOCCUS; HALOFERAX; HALORUBRUM; NATRONOBACTERIUM; and NATRONOCOCCUS.Ice: The solid substance formed by the FREEZING of water.Molecular Dynamics Simulation: A computer simulation developed to study the motion of molecules over a period of time.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Economic Recession: Significant decline in economic activity spread across the economy, lasting more than a few months, normally visible in real gross domestic product, real income, employment, industrial production, and wholesale-retail sales. (National Bureau of Economic Research, Inc, www.nber.org/cycles.html, accessed 4/23/2009)Capillary Tubing: Hollow cylindrical objects with an internal diameter that is small enough to fill by and hold liquids inside by CAPILLARY ACTION.Excipients: Usually inert substances added to a prescription in order to provide suitable consistency to the dosage form. These include binders, matrix, base or diluent in pills, tablets, creams, salves, etc.Technology, Pharmaceutical: The application of scientific knowledge or technology to pharmacy and the pharmaceutical industry. It includes methods, techniques, and instrumentation in the manufacture, preparation, compounding, dispensing, packaging, and storing of drugs and other preparations used in diagnostic and determinative procedures, and in the treatment of patients.Glass: Hard, amorphous, brittle, inorganic, usually transparent, polymerous silicate of basic oxides, usually potassium or sodium. It is used in the form of hard sheets, vessels, tubing, fibers, ceramics, beads, etc.Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.Transition Temperature: The temperature at which a substance changes from one state or conformation of matter to another.Construction Materials: Supplies used in building.Air Microbiology: The presence of bacteria, viruses, and fungi in the air. This term is not restricted to pathogenic organisms.Bedding and Linens: Articles of cloth, usually cotton or rayon and other synthetic or cotton-blend fabrics, used in households, hospitals, physicians' examining rooms, nursing homes, etc., for sheets, pillow cases, toweling, gowns, drapes, and the like.

Probing interactions between HIV-1 reverse transcriptase and its DNA substrate with backbone-modified nucleotides. (1/7757)

BACKGROUND: To gain a molecular understanding of a biochemical process, the crystal structure of enzymes that catalyze the reactions involved is extremely helpful. Often the question arises whether conformations obtained in this way appropriately reflect the reactivity of enzymes, however. Rates that characterize transitions are therefore compulsory experiments for the elucidation of the reaction mechanism. Such experiments have been performed for the reverse transcriptase of the type 1 human immunodeficiency virus (HIV-1 RT). RESULTS: We have developed a methodology to monitor the interplay between HIV-1 RT and its DNA substrate. To probe the protein-DNA interactions, the sugar backbone of one nucleotide was modified by a substituent that influenced the efficiency of the chain elongation in a characteristic way. We found that strand elongation after incorporation of the modified nucleotide follows a discontinuous efficiency for the first four nucleotides. The reaction efficiencies could be correlated with the distance between the sugar substituent and the enzyme. The model was confirmed by kinetic experiments with HIV-1 RT mutants. CONCLUSIONS: Experiments with HIV-1 RT demonstrate that strand-elongation efficiency using a modified nucleotide correlates well with distances between the DNA substrate and the enzyme. The functional group at the modified nucleotides acts as an 'antenna' for steric interactions that changes the optimal transition state. Kinetic experiments in combination with backbone-modified nucleotides can therefore be used to gain structural information about reverse transcriptases and DNA polymerases.  (+info)

Crystal structure of an MHC class I presented glycopeptide that generates carbohydrate-specific CTL. (2/7757)

T cell receptor (TCR) recognition of nonpeptidic and modified peptide antigens has been recently uncovered but is still poorly understood. Immunization with an H-2Kb-restricted glycopeptide RGY8-6H-Gal2 generates a population of cytotoxic T cells that express both alpha/beta TCR, specific for glycopeptide, and gamma/delta TCR, specific for the disaccharide, even on glycolipids. The crystal structure of Kb/RGY8-6H-Gal2 now demonstrates that the peptide and H-2Kb structures are unaffected by the peptide glycosylation, but the central region of the putative TCR binding site is dominated by the extensive exposure of the tethered carbohydrate. These features of the Kb/RGY8-6H-Gal2 structure are consistent with the individual ligand binding preferences identified for the alpha/beta and gamma/delta TCRs and thus explain the generation of a carbohydrate-specific T cell response.  (+info)

Structural basis of Rab effector specificity: crystal structure of the small G protein Rab3A complexed with the effector domain of rabphilin-3A. (3/7757)

The small G protein Rab3A plays an important role in the regulation of neurotransmitter release. The crystal structure of activated Rab3A/GTP/Mg2+ bound to the effector domain of rabphilin-3A was solved to 2.6 A resolution. Rabphilin-3A contacts Rab3A in two distinct areas. The first interface involves the Rab3A switch I and switch II regions, which are sensitive to the nucleotide-binding state of Rab3A. The second interface consists of a deep pocket in Rab3A that interacts with a SGAWFF structural element of rabphilin-3A. Sequence and structure analysis, and biochemical data suggest that this pocket, or Rab complementarity-determining region (RabCDR), establishes a specific interaction between each Rab protein and its effectors. RabCDRs could be major determinants of effector specificity during vesicle trafficking and fusion.  (+info)

Phe161 and Arg166 variants of p-hydroxybenzoate hydroxylase. Implications for NADPH recognition and structural stability. (4/7757)

Phe161 and Arg166 of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens belong to a newly discovered sequence motif in flavoprotein hydroxylases with a putative dual function in FAD and NADPH binding [1]. To study their role in more detail, Phe161 and Arg166 were selectively changed by site-directed mutagenesis. F161A and F161G are catalytically competent enzymes having a rather poor affinity for NADPH. The catalytic properties of R166K are similar to those of the native enzyme. R166S and R166E show impaired NADPH binding and R166E has lost the ability to bind FAD. The crystal structure of substrate complexed F161A at 2.2 A is indistinguishable from the native enzyme, except for small changes at the site of mutation. The crystal structure of substrate complexed R166S at 2.0 A revealed that Arg166 is important for providing an intimate contact between the FAD binding domain and a long excursion of the substrate binding domain. It is proposed that this interaction is essential for structural stability and for the recognition of the pyrophosphate moiety of NADPH.  (+info)

Identification of 17-methyl-18-norandrosta-5,13(17-dien-3beta-ol, the C19 fragment formed by adrenal side chain cleavage of a 20-aryl analog of (20S)-20-hydroxycholesterol. (5/7757)

Incubation of (20R)-20-phenyl-5-pregnene-3beta,20-diol, an aromatic analog of (23S)-20-hydroxycholesterol, with an adrenal mitochondrial preparation leads to the formation of four compounds: pregnenolone, phenol, a C8 ketone, acetophenone, and a nonpolar C19 compound. This latter compound has now been identified by reverse isotope dilution analysis and by gas chromatography/mass spectrometry as 17-methyl-18-norandrosta-5,13(17)-dien-3beta-ol. From these results it is evident that enzymatic fission of the C-17,20 bond of this synthetic derivative occurs. On the other hand, when (20S)-20-hydroxy[21-14C]cholesterol was used as substrate, the analogous cleavage did not take place. Thus, substitution of an aromatic group on C-20 facilitates side chain cleavage between that carbon atom and the nucleus whereas neither of the naturally occuring precursors, cholesterol or its 20-hydroxylated counterpart, are metabolized to a C8 fragment.  (+info)

Relationship between supersaturation and calcium oxalate crystallization in normals and idiopathic calcium oxalate stone formers. (6/7757)

BACKGROUND: In an earlier study on recurrent CaOx stone formers with no detectable abnormalities, we found that the urine of these subjects had a lower tolerance to oxalate load than controls and that the removal of urinary macromolecules with a molecular weight greater than 10,000 D improved their tolerance to oxalate. METHODS: The effects on CaOx crystallization of reduced urinary supersaturation of calcium oxalate (CaOx), induced by night water load, were studied in 12 normal males and in 15 male OxCa stone formers who were free from urinary metabolic abnormalities. The effect of the macromolecules, purified and retrieved from the natural and diluted urine, were analyzed in a metastable solution of CaOx. RESULTS: The water load caused an increase in urine volume (from 307 +/- 111 to 572 +/- 322 ml/8 hr, P = 0.014 in normal subjects, and from 266 +/- 92 to 518 +/- 208 ml/8 hr, P = 0.001 in the stone formers) and a concomitant reduction of the relative CaOx supersaturation (from 8.7 +/- 2.5 to 5.1 +/- 2.5 ml/8 hr, P = 0.001 in normal subjects, and from 10.4 +/- 3.5 to 5.0 +/- 2.7 ml/8 hr, P = 0.001 in the stone formers). The decrease in CaOx supersaturation was accompanied by an increase of the permissible increment in oxalate, both in normal subjects (from 43.8 +/- 10.1 to 67.2 +/- 30. 3 mg/liter, P = 0.018) and in the stone formers (from 25.7 +/- 9.4 to 43.7 +/- 17.1 mg/liter, P = 0.0001), without any significant variations of the upper limit of metastability for CaOx (from 21.6 +/- 5.3 to 20.5 +/- 4.2 mg/liter in normal subjects, and from 18.7 +/- 4.5 to 17.1 +/- 3.7 mg/liter in the stone formers). The inhibitory effect of urinary macromolecules with molecular weight greater than 10,000 Daltons did not undergo any change when the latter were recovered from concentrated or diluted urine, either in normal subjects or in the stone formers. CONCLUSIONS: Reduced CaOx supersaturation by means of water load has a protective effect with regards to CaOx crystallization in subjects who do not present any of the common urinary stone risk factors.  (+info)

Cryoelectron microscopy of a nucleating model bile in vitreous ice: formation of primordial vesicles. (7/7757)

Because gallstones form so frequently in human bile, pathophysiologically relevant supersaturated model biles are commonly employed to study cholesterol crystal formation. We used cryo-transmission electron microscopy, complemented by polarizing light microscopy, to investigate early stages of cholesterol nucleation in model bile. In the system studied, the proposed microscopic sequence involves the evolution of small unilamellar to multilamellar vesicles to lamellar liquid crystals and finally to cholesterol crystals. Small aliquots of a concentrated (total lipid concentration = 29.2 g/dl) model bile containing 8.5% cholesterol, 22.9% egg yolk lecithin, and 68.6% taurocholate (all mole %) were vitrified at 2 min to 20 days after fourfold dilution to induce supersaturation. Mixed micelles together with a category of vesicles denoted primordial, small unilamellar vesicles of two distinct morphologies (sphere/ellipsoid and cylinder/arachoid), large unilamellar vesicles, multilamellar vesicles, and cholesterol monohydrate crystals were imaged. No evidence of aggregation/fusion of small unilamellar vesicles to form multilamellar vesicles was detected. Low numbers of multilamellar vesicles were present, some of which were sufficiently large to be identified as liquid crystals by polarizing light microscopy. Dimensions, surface areas, and volumes of spherical/ellipsoidal and cylindrical/arachoidal vesicles were quantified. Early stages in the separation of vesicles from micelles, referred to as primordial vesicles, were imaged 23-31 min after dilution. Observed structures such as enlarged micelles in primordial vesicle interiors, segments of bilayer, and faceted edges at primordial vesicle peripheries are probably early stages of small unilamellar vesicle assembly. A decrease in the mean surface area of spherical/ellipsoidal vesicles was correlated with the increased production of cholesterol crystals at 10-20 days after supersaturation by dilution, supporting the role of small unilamellar vesicles as key players in cholesterol nucleation and as cholesterol donors to crystals. This is the first visualization of an intermediate structure that has been temporally linked to the development of small unilamellar vesicles in the separation of vesicles from micelles in a model bile and suggests a time-resolved system for further investigation.  (+info)

Purification and properties of a low-molecular-weight, high-alkaline pectate lyase from an alkaliphilic strain of Bacillus. (8/7757)

A low-molecular-weight, high-alkaline pectate lyase (pectate transeliminase, EC 4.2.2.2) was found in an alkaline culture of Bacillus sp. strain KSM-P15, purified to homogeneity, and crystallized. The enzyme had a relative molecular weight of approximately 20,300 as measured by sedimentation equilibrium, with a sedimentation coefficient (s20,w0) of 1.73 S. It was a basic protein with an isoelectric point of pH 10.3, and the alpha-helical content was only 6.6%. In the presence of Ca2+ ions, the enzyme degraded polygalacturonic acid in a random manner to yield 4,5-unsaturated oligo-galacturonides and had its optimal activity around pH 10.5 and 50-55 degrees C. It also had a protopectinase-like activity on cotton fibers. The N-terminal amino acid sequences of the intact protein (28 amino acids) and its two lysyl endopeptidase-cleaved peptide fragments (8 and 12 amino acids) had very low sequence similarity with pectate lyases reported to date. These results strongly suggest that the pectate lyase of Bacillus sp. strain KSM-P15 may be a novel enzyme and belongs in a new family.  (+info)

*Crystallization

Tank crystallization is an old method still used in some specialized cases. Saturated solutions, in tank crystallization, are ... In chemical engineering, crystallization occurs in a crystallizer. Crystallization is therefore related to precipitation, ... In crystallization Nucleation is the step where the solute molecules or atoms dispersed in the solvent start to gather into ... Crystallization is the (natural or artificial) process by which a solid forms, where the atoms or molecules are highly ...

*Crystallization adjutant

A crystallization adjutant is a material used to promote crystallization, normally in a context where a material does not ... 1991). Crystallization of membrane proteins. CRC Press. M Caffrey (2003). "Membrane protein crystallization". J. Struct. Biol. ... Crystallization adjutants are considered additives when they are effective at relatively low concentrations. The distinction ... Additives for protein crystallization and concentration range Quantitative structure-activity relationship of human neutrophil ...

*Strain crystallization

... is a phenomenon in which an initially amorphous solid material undergoes a phase transformation due to ... Strain crystallization occurs in natural rubber and some other elastomers. The phenomenon has important effects on strength and ... Crystallization can also be observed indirectly through its effects on stress-strain and fatigue behavior. Natural rubber ( ... ISBN 3-446-17010-3. B. Huneau, STRAIN-INDUCED CRYSTALLIZATION OF NATURAL RUBBER: A REVIEW OF X-RAY DIFFRACTION INVESTIGATIONS, ...

*Crystallization (love)

This journey or crystallization process, shown above, was detailed by Stendhal on the back of a playing card while speaking to ... Crystallization is a concept, developed in 1822 by the French writer Stendhal, which describes the process, or mental ... Stripped of its leaves by the winter it was certainly anything but dazzling until the crystallization of the salt covered its ... Here they discovered the phenomenon of salt "crystallization" and used it as a metaphor for human relationships. "In the salt ...

*Crystallization (disambiguation)

Crystallization or Crystallize may also refer to: Protein Crystallization, a technique required for protein X-Ray ... Crystallization is the (natural or artificial) formation of highly-organized, solid crystals. ... song by The xx Crystallization (love), the "falling in love" process (Stendhal). ...

*Adolescent crystallization

During the crystallization period, adolescents begin to form their own ideas about what is appropriate work for them and learn ... Therefore, the crystallization of career opportunities is more likely to occur in adolescents given the chance to explore and ... Adolescent crystallization, as defined by Laurence Steinberg, is a stage during adolescence in which individuals, typically ... Both the males and the females showed stability in their choices and crystallization increased with age. The study showed the ...

*Fractional crystallization

... may refer to: Fractional crystallization (chemistry), a process to separate different solutes from a ... solution Fractional crystallization (geology), a natural process occurring in igneous rocks during which precipitation of ...

*Crystallization of polymers

The most basic model for polymer crystallization kinetics comes from Hoffman nucleation theory. The crystallization process of ... induces interaction between molecular chains and a possible crystallization as in the crystallization from the melt. ... presence of straight chains with regularly spaced side groups facilitates crystallization. For example, crystallization occurs ... Another type of crystallization occurs upon extrusion used in making fibers and films. In this process, the polymer is forced ...

*Fractional crystallization (chemistry)

In chemistry, fractional crystallization is a method of refining substances based on differences in solubility. It fractionates ... Fractional crystallization (geology) Fractional freezing Laser-heated pedestal growth Pumpable ice technology Recrystallization ... via differences in crystallization (forming of crystals). If a mixture of two or more substances in solution are allowed to ...

*Fractional crystallization (geology)

Fractional crystallization in silicate melts (magmas) is complex compared to crystallization in chemical systems at constant ... as in near-solidus crystallization of magmas of granite composition. The crystallization sequence of oxide minerals such as ... One example concerns crystallization of melts that form mafic and ultramafic rocks. MgO and SiO2 concentrations in melts are ... In essence, fractional crystallization is the removal of early formed crystals from an originally homogeneous magma (for ...

*Water of crystallization

In chemistry, water of crystallization or water of hydration or crystallization water is water that occurs inside crystals. ... Classically, "water of crystallization" refers to water that is found in the crystalline framework of a metal complex or a salt ... Water of crystallization can generally be removed by heating a sample but the crystalline properties are often lost. For ... In some contexts, water of crystallization is the total weight of water in a substance at a given temperature and is mostly ...

*Urea extraction crystallization

The urea extraction crystallization is a process for separating linear paraffins (n-paraffins, n-alkanes) from hydrocarbon ...

*International Organization for Biological Crystallization

The International Organization for Biological Crystallization (IOBCr) is a non-profit, scientific organization for scientists ... The last International Conferences on Crystallization of Biological Macromolecules ICCBM15 was held in Hamburg, Germany. ... who study the crystallization of biological macromolecules and develop crystallographic methodologies for their study. It was ... founded in 2002 to create a permanent organ for the organization of the International Conferences for the crystallization of ...

*PreQ1 synthase

"Crystallization". Acta Crystallogr. F. 61 (Pt 10): 945-8. doi:10.1107/S1744309105029246. PMC 1991305 . PMID 16511203. Chikwana ...

*Social norm

Crystallization. Finally, norm crystallization refers to how much variance exists within the curve; translated from the ... A group norm like how many cups of coffee first years should drink would probably have low crystallization, since a lot of ... Showing the overall group norm, the return potential model in Figure 1 does not indicate the crystallization. However, a return ... the norm of not plagiarizing another student's work would likely have high crystallization, as people uniformly agree on the ...

*Alan Neville Gent

Mechanics of rubber spring systems; viscoelastic behavior of polymers; stress relaxation; failure processes; crystallization. A ...

*Arab Potash

Cold Crystallization Plant I: The cold crystallization plant is independent of the hot leach facility. It is operated under ... Drying Cold Crystallization Plant II: A second Cold Crystallization Plant (II) came into operation in September 2010 to give a ... The new plant is much similar to the Cold Crystallization Plant I, but it encompasses certain areas of modified processes and ... It includes the following processes: Carnallite Receiving; Flotation; Crystallization; Cold Leaching; ...

*Canavalin

The crystallization of jack bean seed proteins has been studied extensively since the early 20th century and was of particular ... Canavalin has since been used as a model system for studying protein crystallization, most notably in the study of protein ... McPherson, Alexander; DeLucas, Lawrence James (2015-09-03). "Microgravity protein crystallization". npj Microgravity. 1 (1). ... though Sumner's group never fully characterized canavalin and it remained of little interest until its crystallization ...

*Cytochrome c

ISBN 978-0-7167-0174-3. McPherson A, Delucas LJ (2015). "Microgravity protein crystallization". Npj Microgravity. 1: 15010. doi ...

*Ergothioneine

Purification and crystallization. Site of formation and function". Biochem. J. 53 (1): 140-8. PMC 1198115 . PMID 13032046. ...

*Turnip yellow mosaic virus

McPherson, Alexander; Delucas, Lawrence James (2015). "Microgravity protein crystallization". Npj Microgravity. 1: 15010. doi: ...

*L-lactate dehydrogenase (cytochrome)

... purification and crystallization". Biochem. J. 71 (3): 492-9. PMC 1196822 . PMID 13638255. Appleby CA, Morton RK (November 1959 ...

*Space manufacturing

Koszelak, S; Leja, C; McPherson, A (1996). "Crystallization of biological macromolecules from flash frozen samples on the ... "Microgravity protein crystallization". Npj Microgravity. 1: 15010. doi:10.1038/npjmgrav.2015.10. ...

*Orlin D. Velev

"Two-dimensional crystallization". Nature. 361 (6407): 26-26. doi:10.1038/361026a0. Bharti, Bhuvnesh; Rutkowski, David; Han, ... "Porous silica via colloidal crystallization". Nature. 389 (6650): 447-448. doi:10.1038/38921. ISSN 0028-0836. Velev, O. D.; ...

*Phosphoenolpyruvate carboxykinase (diphosphate)

Crystallization and properties". J. Biol. Chem. 241: 5678-5691. PMID 4288896. Phosphoenolpyruvate carboxykinase ...
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Cytochrome c peroxidase was isolated from Paracoccus denitrificans and purified to homogeneity in three steps prior to crystallization. Two different diffraction-quality crystal forms were obtained by the hanging-drop vapour-diffusion method using a number of screening conditions. The best (needle-shaped) crystal form is suitable for structural studies and was grown from solutions containing 20% PEG 8000, 0.1 M Tris pH 8.5 and 0.2 M MgCl(2). Crystals grew to a maximum length of approximately 0.7 mm and belong to the primitive monoclinic space group P2(1), with unit-cell parameters a = 78.3, b = 51.0, c = 167.2 A, beta = 97.9 degrees. After a dehydration step and extensive optimization of the cryocooling conditions, a complete data set was collected to 2.2 A from a native crystal of the fully oxidized form of the enzyme using synchrotron radiation.
The quality of a crystallization process greatly influences the quality of the final product. Our new white paper introduces you to the fundamentals of crystallization and provides guidance for the design of a high quality crystallization process.
Upon release from the stable complex formed with its antitoxin VapB, the toxin VapC (MvpT) of the Gram-negative pathogen Shigella flexneri is capable of globally down-regulating translation by specifically cleaving initiator tRNA(fMet) in the anticodon region. Recombinant Shigella flexneri VapC(D7A) harbouring an active-site mutation was overexpressed in Escherichia coli, purified to homogeneity and crystallized by the vapour-diffusion technique. A preliminary X-ray crystallographic analysis shows that the crystals diffracted to at least 1.9 Å resolution at a synchrotron X-ray source and belonged to the trigonal space group in the hexagonal setting, H3, with unit-cell parameters a = b = 120.1, c = 52.5 Å, α = β = 90, γ = 120°. The Matthews coefficient is 2.46 Å(3) Da(-1), suggesting two molecules per asymmetric unit and corresponding to a solvent content of 50.0 ...
Purification, circular dichroism analysis, crystallization and preliminary X-ray diffraction analysis of the F plasmid CcdB killer protein ...
The transformation from a fluid to a crystal can be complicated and involve one or more precursors. Such multistep crystallization pathways occur in many chemical and physical systems, and the driving force for the appearance of the precursors has been explained by unique characteristics of the interactions among the systems building blocks. We investigated multistep crystallization pathways in hard particles, where interaction is dictated solely by building-block shape and thus entropy. We categorized multistep crystallization pathways based on the dimension of the prenucleation motifs, and discuss possible comparisons to other crystallization processes.. ...
My research into crystallization processes in magma chambers has involved investigation of both natural and artificial magmatic systems. Artifical magmas, such as those produced by In-Situ Vitrification allow a unique window into the crystallization processes of magma, as does investigation of crystals forming in the active lava lake of Mount Erebus, Antarctica REFERENCES:. DUNBAR, N.W., CASHMAN, K.V., AND DUPRE, R., 1994. Crystallization processes of anorthoclase phenocrysts in the Mt. Erebus magmatic system: Evidence from crystal composition, crystal size distributions and volatile contents of melt inclusions. In: Volcanological Studies of Mount Erebus. Antarctic Research Series, 66, 129-146. ABSTRACT. DUNBAR, N.W., JACOBS, G.K. AND NANEY, M.T., 1995. Crystallization processes in an artificial magma: variations in crystal shape, growth rate and composition with melt cooling history. Contrib. Mineral. Petrol. 120, 412-425. ABSTRACT. JACOBS, G.K., DUNBAR, N.W., NANEY, M.T., and WILLIAMS, R.T., ...
Anni presents a wealth of insight and information on the Crystallization Process and how it can potentially impact us on the journey to becoming fully fledged Crystal Humans. There is also real magic and crystal energy at work through the pages of "The Crystal Human and the Crystallization Part I" and "The Crystal Human and the Crystallization Part II". Reviewing these two books triggered my own crystallisation journey, and fortunately the relevant guidance was to hand as I worked my way through the books".. June McGuire - Management Consultant and Holistic Therapist. ...
The study of proteins involved in de novo biosynthesis of purine nucleotides is central in the development of antibiotics and anticancer drugs. In view of this, a protein from the hyperthermophile Pyrococcus horikoshii OT3 was isolated, purified and crystallized using the microbatch method. Its primary structure was found to be similar to that of SAICAR synthetase, which catalyses the seventh step of de novo purine biosynthesis. A diffraction-quality crystal was obtained using Hampton Research Crystal Screen II condition No. 34, consisting of 0.05 M cadmium sulfate hydrate, 0.1 M HEPES buffer pH 7.5 and 1.0 M sodium acetate trihydrate, with 40%(v/v) 1,4-butanediol as an additive. The crystal belonged to space group P3(1), with unit-cell parameters a = b = 95.62, c = 149.13 angstrom. Assuming the presence of a hexamer in the asymmetric unit resulted in a Matthews coefficient (V-M) of 2.3 angstrom(3) Da(-1), corresponding to a solvent content of about 46%. A detailed study of this protein will ...
Adherent and pin-hole free amorphous Sb2Te3 thin films have been obtained by vacuum evaporation at substrate temperatures ≤25 °C. The films have been crystallized by thermal and laser annealing, and the crystallization processes monitored as a function of annealing temperature and laser scan speed. A comparative study of topography reveals disk-shaped crystallized areas in thermal crystallization and dendrite growth in the laser induced process. The crystallized films in both cases contain a single Sb2Te3 phase. Activation energy of 2 eV for crystallization, determined using differential scanning calorimetery indicates good room temperature stability of the amorphous states ...
Pengju Pan, Jianna Bao, Xiaohua Chang, Ruoxing Chang, Guorong Shan, Yongzhong Bao. State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, P. R. China.. Supramolecular polymers (SMPs) have different crystallization behavior from conventional polymers. Crystallization of SMPs occurs in a "confined" and "dynamic" manner. Because of the reversible and stimuli-responsive natures of non-covalent bonds in SMPs, crystalline structure and crystallization kinetics of SMPs depend strongly on crystallization conditions (e.g., crystallization temperature, Tc). This offers a feasible way to tune the physical properties and functions of SMPs in processing. We first selected the 2-ureido-4[1H]-pyrimidione (UPy)-bonded poly(L-lactic acid) (PLLA) as a model SMP and investigated the crystallization kinetics, polymorphic crystalline structure, and phase transition of supramolecular PLLAs (SM-PLLAs). Crystallization rate and ...
The laboratory of Chemistry of Biological Processes is equipped with state of the art devices for the crystallization of biological macromolecules. The laboratory houses a Mosquito® Crystal (TTPLabtech) that allows the automated screening of crystallization conditions using low sample volumes and zero cross-contaminations. The robot allows the setup of sitting and hanging drop vapor diffusion trials and can perform microbatch under oil if desired. Our laboratory also owns a 5-head Dragonfly® (TTPLabtech) as a companion for the Mosquito®, which allows the setup of crystallizations screens for crystal optimization. To check the crystallization experiments, two stereomicroscopes are available including a LEICA M205C equipped with a camera IC80 HD. ...
The nonisothermal crystallization kinetics was investigated by differential scanning calorimetry for the nylon 6/graphene composites prepared by in situ polymerization. The Avrami theory modified by Jeziorny, Ozawa equation, and Mo equation was used to describe the nonisothermal crystallization kinetics. The analysis based on the Avrami theory modified by Jeziorny shows that, at lower cooling rates (at 5, 10, and 20 K/min), the nylon 6/graphene composites have lower crystallization rate than pure nylon 6. However, at higher cooling rates (at 40 K/min), the nylon 6/graphene composites have higher crystallization rate than pure nylon 6. The values of Avrami exponent m and the cooling crystallization function F(T) from Ozawa plots indicate that the mode of the nucleation and growth at initial stage of the nonisothermal crystallization may be as follows: two-dimensional (2D), then one-dimensional (1D) for all samples at 5-10 °C/min; three-dimensional (3D) or complicated than 3D, then 2D and 1D at ...
20Li(2)O-80TeMO(2) glasses were heat annealed at different temperatures between T-g and T-x and studied by using XRD, FTIR spectroscopy and DSC techniques to understand the crystallization kinetics in this glass matrix. The infrared band structure of this glass is similar to what was observed in glassy TeO2. XRD results reveal the presence of three distinct crystalline gamma-TeO2, alpha-TeO2 and Li2Te2O5 phases during the crystallization process. This is a first report of gamma-TeO2 phase crystallization in this glass matrix. DSC results confinn the crystallization of three distinct structures in the glass. In summary, our results suggest a crystallization hierarchy on this glass matrix since the gamma-TeO2 and alpha-TeO2 phases crystallization occurs before the Li2Te2O5 phase crystallization. (c) 2006 Elsevier B.V. All rights reserved.. ...
Vol 70: Purification, crystallization and preliminary X-ray crystallographic studies of Rv3705c from Mycobacterium tuberculosis.. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
The Czochralski (CZ) crystallization process is used to produce monocrystalline silicon. Monocrystalline silicon is used in solar cell wafers and in computers and electronics. The CZ process is a batch process, where multicrystalline silicon is melted in a crucible and later solidi es on a monocrystalline seed crystal. The crucible is heated using a heating element where the power is manipulated using a triode for alternating current (TRIAC). As the electric resistance of the heating element increases by increased temperature, there are signi cant dynamics from the TRIAC input signal (control system output) to the actual (measured) heating element power. The present paper focuses on empirical modeling of these dynamics. The modeling is based on a dataset logged from a real-life CZ process. Initially the dataset is preprocessed by detrending and handling outliers. Next, linear ARX, ARMAX, and output error (OE) models are identi ed. As the linear models do not fully explain the process behavior, ...
If you have a question about this talk, please contact Duncan Johnstone.. The lecture will highlight three experimental strategies that we have developed for exploring crystallization pathways and structural properties of solids: (i) in-situ solid-state NMR techniques for understanding the time-evolution of crystallization processes, (ii) the study of X-ray birefringence for spatially resolved mapping of the distribution of molecular orientations in materials, and (iii) structure determination of organic materials when single crystals cannot be prepared.. Our in-situ solid-state NMR technique [1-3] for studying crystallization pathways exploits the ability of NMR to selectively detect the solid phase in heterogeneous solid/liquid systems of the type that exist during crystallization from solution. We have shown that this technique can establish the sequence of solid phases formed during crystallization processes [1] and can be exploited in the discovery of new polymorphs [2]. Our most recent ...
View Notes - GEOL101 - Slideshow 101.10 Magma from GEOL 101 at Central Washington University. Magma Magma Melting Crystallization Processes that impact composition Magma Creation of
An initial tranche of results from day-to-day use of a robotic system for setting up 100 nl-scale vapour-diffusion sitting-drop protein crystallizations has been surveyed. The database of over 50 unrelated samples represents a snapshot of projects currently at the stage of crystallization trials in Oxford research groups and as such encompasses a broad range of proteins. The results indicate that the nanolitre-scale methodology consistently identifies more crystallization conditions than traditional hand-pipetting-style methods; however, in a number of cases successful scale-up is then problematic. Crystals grown in the initial 100 nl-scale drops have in the majority of cases allowed useful characterization of X-ray diffraction, either in-house or at synchrotron beamlines. For a significant number of projects, full X-ray diffraction data sets have been collected to 3 Šresolution or better (either in-house or at the synchrotron) from crystals grown at the 100 nl scale. To date, five structures ...
The protozoan parasites of the Apicomplexa phylum are devastating global pathogens. Their success is largely due to phylum-specific proteins found in specialized organelles and cellular structures. The inner membrane complex (IMC) is a unique apicomplexan structure that is essential for motility, invasion and replication. The IMC subcompartment proteins (ISP) have recently been identified in Toxoplasma gondii and shown to be critical for replication, although their specific mechanisms are unknown. Structural characterization of TgISP1 was pursued in order to identify the fold adopted by the ISPs and to generate detailed insight into how this family of proteins functions during replication. An N-terminally truncated form of TgISP1 was purified from Escherichia coli, crystallized and subjected to X-ray diffraction analysis. Two crystal forms of TgISP1 belonging to space groups P4(1)32 or P4(3)32 and P2(1)2(1)2(1) diffracted to 2.05 and 2.1 Å resolution, respectively ...
The work presented in this thesis represents the study of the polymorphism exhibited by several molecular, organic solid-state systems. In-situ techniques are used to explore aspects of the polymorphism and crystallization behaviour displayed by these systems. The crystal structures of new polymorphs and other solid phases are determined directly from powder X-ray diffraction data. Chapter 1 provides background information on the phenomenon of polymorphism and the importance of its study. In addition, the range of in-situ techniques that have been used to study crystallization and solid-state systems is described. Chapter 2 gives details on the experimental techniques used in the work presented in this thesis. These include powder X-ray diffraction (including the methodology behind structure determination from powder X-ray diffraction data), solid-state nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy, thermal analysis techniques and dynamic vapour sorption. ...
A metal induced crystallization process is provided which employs an amorphous silicon film precursor deposited by physical vapor deposition, wherein the precursor film does not readily undergo crystallization by partial solid phase crystallization. Using this physical vapor deposition amorphous silicon precursor film, the amorphous silicon film is transformed to polysilicon by metal induced crystallization wherein the crystalline growth occurs fastest at regions that have been augmented with a metal catalyst and proceeds extremely slowly, practically zero, at regions which bear no metal catalyst. Accordingly, by use of the physical vapor deposition amorphous silicon precursor film in the process of the present invention, the metal induced crystallization process may take place at higher annealing temperatures and shorter annealing times without solid phase crystallization taking place. The process has a faster throughput than previous metal induced crystallization processes, results in a polysilicon
Crystallization from lipidic mesophase matrices is a promising route to diffraction-quality crystals and structures of membrane proteins. The microfluidic approach reported here eliminates two bottlenecks of the standard mesophase-based crystallization protocols: (i) manual preparation of viscous mesophases and (ii) manual harvesting of often small and fragile protein crystals. In the approach reported here, protein-loaded mesophases are formulated in an X-ray transparent microfluidic chip using only 60 nL of the protein solution per crystallization trial. The X-ray transparency of the chip enables diffraction data collection from multiple crystals residing in microfluidic wells, eliminating the normally required manual harvesting and mounting of individual crystals. In addition, we validated our approach by on-chip crystallization of photosynthetic reaction center, a membrane protein from Rhodobacter sphaeroides, followed by solving its structure to a resolution of 2.5 Å using X-ray ...
Glutathione synthetases catalyze the ATP-dependent synthesis of glutathione from L-γ-glutamyl-L-cysteine and glycine. Although these enzymes have been sequenced and characterized from a variety of biological sources, their exact catalytic mechanism is not fully understood and nothing is known about their adaptation at extremophilic environments. Glutathione synthetase from the Antarctic eubacterium Pseudoalteromonas haloplanktis (PhGshB) has been expressed, purified and successfully crystallized. An overall improvement of the crystal quality has been obtained by adapting the crystal growth conditions found with vapor diffusion experiments to the without-oil microbatch method. The best crystals of PhGshB diffract to 2.34 Å resolution and belong to space group P212121, with unit-cell parameters a = 83.28 Å, b = 119.88 Å, c = 159.82 Å. Refinement of the model, obtained using phases derived from the structure of the same enzyme from Escherichia coli by molecular replacement, is in progress. The
Given by Dr Fabric Gorrec, LMB, Cambridge, UK. Advances in macromolecular X-ray crystallography depends upon solving structures from samples containing purified and concentrated protein, DNA, RNA, and their complexes. Novel samples are however increasingly challenging to produce and crystallize hence innovations which enhance the process of structure determination are urgently required, especially to increase the yield of quality diffraction crystals.. Experienced researchers from related fields, students and non-experts alike will find this webinar essential as it provides both theoretical and experimental evidence-based aspects of macromolecular X-ray crystallography. Delegates will leave with a better understanding about the underlying reasons why it is necessary to formulate novel crystallization screens with relatively complex conditions, such as the ones found in the MORPHEUS screens.. ...
PLA (Poly Lactic Acid) is a bio-sourced and biodegradable polymer. It represents an alternative for polymers issued from petrochemical synthesis. Unfortunately, the crystallization kinetics of PLA is very slow and limits the possibility to extend its application in several industrials domains. The enhancement of the PLA crystallization kinetic can be obtained by addition of nucleating agents of by ordering the molecular chains during flow, as in processing conditions. During processing of thermoplastic polymer experiences several thermomechanical conditions influencing drastically its final properties and mechanical behavior. During injection molding process, macromolecules are oriented and ordered due to the shear and elongation imposed by the melt flow in the mold during the filling step. As a consequence, supplementary nucleation is created in the polymer, leading to the acceleration of the crystallization kinetics. In this work, we propose to analyze and to quantify the role of the flow, the ...
The main objective of this work is to propose a mechanism for the transfer of impurities into the sucrose crystal. To this end the transfer of impurities into the sucrose crystal was investigated, under crystallisation conditions similar to those found industrially. Most of the impurities, namely, colour bodies, potassium, calcium and starch, were selected on the basis of their industrial importance, but some exotic species, namely lithium and nickel, were chosen to represent other mono- and di-valent ions respectively, and dyes, such as methylene blue, which have been used in work with single crystal sucrose crystallisation, were included to make the results more general. A parameter to measure the rate at which impurities are transferred into the sucrose crystal was proposed. Experiments, carried out in a pilot plant evaporative crystalliser, were performed to establish the effect of selected factors on both the concentrations of impurities found in the sucrose crystal, and on the rate at ...
The facility provides low volume crystallisation services and screen making. Our customers can also order custom built premixed crystallisation solutions. Full crystallisation service includes composition of the crystallisation setup and scheduled imaging of the experiment for up to four months. The crystallisation droplets are set up using our Mosquito LCP or Oryx nanodrop robots, which can use as little as 100 nl protein per experiment and are suitable for membrane proteins and for air-sensitive samples. Scientists can examine the maturation of the project over time and can pick up the crystallisation plate for an X-ray experiment. The facility is equipped with a dedicated imaging station for combined visible/UV epifluorescence imaging of very small protein crystals (2μm ...
Nonisothermal crystallization, melting behavior, and morphology of polypropylene (PP)/Easy processing polyethylene (EPPE) blends were studied by differential scanning alorimetry (DSC) and scanning electron microscope (SEM). The results showed that PP and EPPE are miscible, and there is no obvious phase separation in microphotographs of the blends. The modified Avrami analysis, Ozawa equation, and also Mo Z.S. method were used to analyze the nonisothermal crystallization kinetics of the blends. Values of Avrami exponent indicated the crystallization nucleation of the blends is homogeneous, the growth of spherulites is tridimensional, and crystallization mechanism of PP is not affected much by EPPE. The crystallization activation energy was estimated by Kissinger method. The result obtained from modified Avrami analysis, Mo Z.S. method, and Kissinger methods were well agreed. The addition of minor EPPE phase favored to decrease the overall crystallization rate of PP, showing some dilution effect ...
Puppo, C., Martini, S., Cerdeira, M., Hartel, R.W., and Herrera, M.L. 2002. Effect of Processing Conditions on Crystallization Kinetics and Rheology of Milk Fat/Sunflower Oil Blends Formulated with and without the Addition of Emulsifiers. 93rd AOCS Annual Meeting & Expo, Montreal, Quebec, Canada (oral presentation). ...
Malonyl-CoA:acyl-carrier protein transacylase (MCAT), encoded by the fabd gene, is a key enzyme in type II fatty-acid biosynthesis. It is responsible for transferring the malonyl group from malonyl-CoA to the holo acyl-carrier protein (ACP). Since the type II system differs from the type I system that mammals use, it has received enormous attention as a possible antibiotic target. In particular, only a single isoform of MCAT has been reported and a continuous coupled enzyme assay has been developed. MCAT from Staphylococcus aureus was overexpressed in Escherichia coli and the protein was purified and crystallized. Diffraction data were collected to 1.2 A ° resolution. The crystals belonged to space group P21, with unit-cell parameters a = 41.608, b = 86.717, c = 43.163 A ° , α = γ = 90, β = 106.330 °. The asymmetric unit contains one SaMCAT molecule ...
MyCrystals is designed as a user-friendly program to display crystal images and list crystallization conditions. The crystallization conditions entry fields can be customized to suit the experiments. MyCrystals is also able to sort the images by the entered crystallization conditions, which presents a unique opportunity to easily assess the effect of, for example, changing pH or concentration and thus establish the best conditions to be used for optimization ...
2004. Cölfen, Helmut. The investigation of crystallization processes is a long established field of science. Crystals have a smallest unit called the unit cell and all crystal forms can be related to it with the consequence that crystals always exhibit planar surfaces. Crystals are built from ions or molecules. Recently, the investigation of so-called biominerals has revealed that not all crystals fit the classical textbook picture. For example biominerals, which are minerals deposited by living organisms like skeletons of algae, exhibit crystal morphologies with complex form, which even show untypical curvature. Thus they deviate significantly from the classical planar crystal surfaces. Furthermore, biominerals are often highly optimised composite materials like bones, teeth or mussle shells. This is achieved by a control of the crystallization process by structure directing molecules. Furthermore, recent investigations have revealed that these crystals are not always formed according to the ...
Methods are described wherein crystallization conditions determined in a microfluidic device are translated into crystallization conditions in alternati...
Escherichia coli ribosomal RNA (rRNA) is post-transcriptionally modified by site-specific enzymes. The role of most modifications is not known and little is known about how these enzymes recognize their target substrates. In this thesis, we have structurally and functionally characterized two S-adenosyl-methionine (SAM) dependent 23S rRNA methyltransferases (MTases) that act during the early stages of ribosome assembly in E. coli.. RlmM methylates the 2O-ribose of C2498 in 23S rRNA. We have solved crystal structures of apo RlmM at 1.9Å resolution and of an RlmM-SAM complex at 2.6Å resolution. The RlmM structure revealed an N-terminal THUMP domain and a C-terminal catalytic Rossmann-fold MTase domain. A continuous patch of conserved positive charge on the RlmM surface is likely used for RNA substrate recognition. The SAM-binding site is open and shallow, suggesting that the RNA substrate may be required for tight cofactor binding. Further, we have shown RlmM MTase activity on in vitro ...
Model-based scale-up and optimisation is a powerful technique for achieving the desired product quality and reducing the cost of experimentation and the time to market. For complex crystallization processes, population balance modelling is capable of predicting the effect of the batch recipe on the particle size distribution (PSD) of the final product. However, this technique is mathematically complex and has traditionally required deep knowledge of specialist areas. New tools allow engineers to apply population balance modelling without highly-specialised numerical skills.. This webinar will present a case study illustrating the application of mechanistic model-based crystallization process analysis, scale-up and optimisation.. ...
Park; though this is too probably a download crystallization and growth of colloidal campaign, I divine Fully killing for one. I set covering fracking Languages Spoken World Korean but it carried almost a Database. much database Id take for a visual quality. Re: Best download crystallization and growth for a compensation to let inflectional? Judah and Jerusalem in the English political download crystallization and growth of colloidal. 14 do simultaneously Ezek 39:23-29, and the day by Renz 1999: 120-121. Barthel 1997: 233, with to 8:18. steady download crystallization and( 734-732 BCE). For this download crystallization and, show Steck 1972: 17-19; Janowski 1989: 185-187. Judah, more again in Zion and Jerusalem( 14:24-25; 31:8-9). 30:27-33( reports 29, 32) and in 9:1-4. Assyria like the download crystallization and growth of Midian at Rock Oreb. is an award-winning production company made up of a team of inspired professionals who create compelling media. Whether its a film, There is no ...
Two different crystal forms of human thioredoxin peroxidase-B have been grown by vapour diffusion using polyethylene glycol 400 as a precipitant. Monoclinic P21 crystals were grown from freshly purified protein, whilst orthorhombic P212121 crystals were grown from purified protein that had been stored in ammonium sulfate, but otherwise under the same conditions. The diffraction from both crystal forms was observed to extend to beyond 2.0 A resolution using synchrotron radiation. Complete native data sets to 1.8 and 3. 7 A have been collected from the monoclinic and orthorhombic crystals, respectively.
This year the course focused on micro and nano crystals and high throughput methods for synchrotrons and XFELs. Forty-three participants and 20 lecturers and tutors from the US and abroad discussed, and experienced hands-on, the complexity of the crystallization process. Nine lectures introducing basic concepts ranging from standard manual and automated crystallization methods to high density crystallization formats and injectors for XFELs preceded the practical and tutorial demonstration sessions. Nine different crystallization robotic systems were utilized and presented to the participants who could probe them during the tutorials to set their own crystallization trials. Twenty-three participants brought their own proteins and took advantage of the different methods being taught during the hands-on sessions. Crystals obtained were tested during the RapiData 2016 course that immediately followed this workshop. Several participants took home new crystallization conditions and even a few ...
Zn²⁺ is an essential nutrient for all known forms of life. In the major human pathogen Streptococcus pneumoniae, the acquisition of Zn²⁺ is facilitated by two Zn²⁺-specific solute-binding proteins: AdcA and AdcAII. To date, there has been a paucity of structural information on AdcA, which has hindered a deeper understanding of the mechanism underlying pneumococcal Zn²⁺ acquisition. Native AdcA consists of two domains: an N-terminal ZnuA domain and a C-terminal ZinT domain. In this study, the ZnuA domain of AdcA was crystallized. The initial crystals of the ZnuA-domain protein were obtained using dried seaweed as a heterogeneous nucleating agent. No crystals were obtained in the absence of the heterogeneous nucleating agent. These initial crystals were subsequently used as seeds to produce diffraction-quality crystals. The crystals diffracted to 2.03 Å resolution and had the symmetry of space group P1. This study demonstrates the utility of heterogeneous nucleation. The solution of ...
Seeded batch crystallizations of monohydrate citric acid were performed under isothermal conditions (15 degrees C). Continuous monitoring of the overall solid concentration during the crystallization process was developed using in situ Raman spectroscopy. Quantitative estimation of the crystal size distribution (CSD) was made possible thanks to in situ image acquisition: off-line CSD measurements were further computed from the recorded pictures. The growth rate of monohydrate citric acid was estimated from solid concentration. Through in situ particle size visualization and quantitative analysis of the pictures, activated surface secondary nucleation was also shown to significantly impact the final CSD. It is underlined that, in addition to continuous Raman in situ spectroscopic concentration measurements, image acquisition yields highly valuable data on the dispersed phase. Advantages and drawbacks of the technique for the monitoring of solution crystallization are discussed.
The mechanism of polymer crystallization is extensively studied and still far away from consensus. This research adopted cluster size distribution kinetics approach to explore the kinetics of polymer crystallization and phase separation within spinodal region. The kinetics of polymer crystallization is studied by integrating nucleation, crystal growth and ripening. Population balance equations based on crystal size distribution and concentration of amorphous polymer segments are solved numerically and the related differential moment equations are also solved. The model accounts for nucleation and crystal growth. Different mass dependences of growth and dissociation rate coefficients are proposed to investigate the fundamental features of crystal growth. The effect of temperature is also investigated for isothermal and nonisothermal polymer crystallization. Incorporating temperature effects of nucleation and crystal growth rate, the model presents time dependencies of polymer concentration, number and
Morphological development during crystallization of thin films of poly(ethylene oxide) (PEO) / poly(methyl methacrylate) (PMMA) blends has been reported. Studies have focused on the effects of the blend composition, PMMA molecular weight, film thickness, and crystallization temperature on the observed crystal morphology. As the blend composition was varied from 90 to 30 wt% PEO, the crystal morphology varied from spherulites to needles and dendrites. Variation of the crystallization temperature and PMMA molecular weight resulted in similar changes in morphology. A morphological map demonstrating the roles of the experimental controls on the observed crystal morphology has been developed. This map was used as a tool for more detailed studies of the observed morphologies and morphological transitions. The dendritic region of the map (~ 30 = 40 wt% PEO) was studied in detail. Changes in the diffusion length were achieved through variation of the PMMA molecular weight, and were shown to influence ...
The Protein Crystallization Diagnostics Facility (PCDF) is an instrument developed by Astrium under an ESA contract to observe and study nucleation and crystallisation processes of molecules from solutions in long duration microgravity experiments on board the International Space Station using advanced diagnostics. The experiment PROTEIN, performed with PCDF, aimed at unravelling physical processes and relating the formation of defects in crystals to their growth conditions. This PCDF experiment was performed on the ISS in 2009, integrated in the European Drawer Rack. The PCDF mission was an important milestone and a basis for future experiments ...
The water-soluble antenna chromoprotein phycocyanin-645 from a Chroomonas species (Cryptophyceae) has been crystallized. X-ray precession photographs prove space groups P3121 (or the enantiomorphic P3
Crystal structures of lithium, sodium, potassium, calcium and magnesium salts of adenosine 2-monophosphate (2-AMP) have been obtained at atomic resolution by X-ray crystallographic methods. 2-AMP.Li belongs to the monoclinic space group P21 with a = 7.472(3)Å, b = 26.853(6) Å, c = 9.184(1)Å, b = 113.36(1)Å and Z= 4. 2-AMP.Na and 2-AMP.K crystallize in the trigonal space groups P31 and P3121 with a = 8.762(1)Å, c = 34.630(5)Å, Z= 6 and a = 8.931(4), Åc = 34.852(9)Å and Z= 6 respectively while 2-AMP.Ca and 2-AMP.Mg belong to space groups P6522 and P21 with cell parameters a = 9.487(2), c = 74.622(13), Z = 12 and a = 4.973(1), b = 10.023(2), c = 16.506(2), beta = 91.1(0) and Z = 2 respectively. All the structures were solved by direct methods and refined by full matrix least-squares to final R factors of 0.033, 0.028, 0.075, 0.069 and 0.030 for 2-AMP.Li, 2-AMP.Na, 2- AMP.K, 2-AMP.Ca and 2-AMP.Mg, respectively. The neutral adenine bases in all the structures are in syn ...
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Salt crystallization is one of the most powerful weathering agents that may cause a rapid change in the mechanical properties of stones, and thus limit their durability. Consequently, determining the mechanical properties of stones due to salt crystallization is important for natural building stones used in marine environmental and mild climatic conditions, which expose excessive salt crystallization cycles. In this study, multivariate regression analysis was performed for estimating the mechanical properties of travertine building stones after salt crystallization test. For this purpose, 12 travertine samples were selected and their physical and mechanical properties (density, porosity, uniaxial compressive strength, Brazilian tensile strength, and P-wave velocity) were determined. Then salt crystallization test was carried out at sodium sulfate solution (Na2SO4) up to 50 cycles and, after every 5 cycles, the uniaxial compressive strength, Brazilian tensile strength and P-wave velocity of the
20141125 Wageningen UR - Mr. Koen Meesters -"Improved sugar recovery by Anti-solvent Crystallisation" Anti-solvent crystallization is when a compound is dissolved in a liquid (the solvent) and adding a second liquid causes the compound to crystallize by reducing its solubility. For beet sugar water is the solvent and several organic anti-solvents were tested. The advantages are abandoning carbonation with energy intensive lime, lower power and heat cost, higher sugar recovery and no centrifugation of crystals needed. The safety requirements, need and cost to recover anti-solvents even at small scale production capacity make this process considerably cheaper overall.. The new anti-solvent crystallization process with its features was explained with small scale experimental results. Pilot facility is planned. http://www.wageningenur.nl/nl/Expertises-Dienstverlening/Onderzoeksinstituten/food-biobased-research.htm. ...
A method of screening protein crystal growth conditions with picogram to microgram amounts of protein in picoliter or nanoliter volumes is provided. A preferred method comprises a microarray with a plurality of micro-chambers in the microarray. A protein solution is placed into the micro-chambers by an automated dispensing mechanism. The protein crystal growth conditions of each of the micro-chambers is adjusted so that the protein crystal growth conditions in at least two of the micro-chambers differs. Crystallization of the protein solution in the micro-chambers is effected. Protein crystal growth in the micro-chambers is then observed.
Crystallization is the major bottleneck to 3D structure determination using X-ray crystallography. In this workshop we will discuss many tenets of successful crystallization for both conventional and serial crystallography. Many topics will be covered including fundamentals of crystal growth, strategies to sample crystallization space, identifying crystal hits, electron microscopy applications of crystal analysis, practical considerations for data analysis, difficult crystallization problems, virus crystallography, and an overview of serial crystallography.
The electron-energy band structure of electric Double Layer (DL) between a molten salt and metal electrode (an anode or cathode) is studied for the electrodepositing crystallization process when the width of DL metal part is less than the one in the molten salt. It is shown that just the molten-salt part of the double layer confines a rate of electrodepositing process. The reason of this is a neutralization of depositing ions into the molten-salt near the electrode and hence their diffusively confined motion in a density gradient field. It is important to minimize the electrodepositing potential for effective component crystallization out of the molten salt and its exchange process including selective extracting of salt components by their crystallization on electrodes of galvanic circuit. It is shown that this can be carried out by means of fine and controllable variation of reduction-oxidation (RedOx) potential of the non-stoichiometric salts. A possible application of a potentiometer for monitoring
systems. Without an overarching system for handling stocks and samples, problems such as stock duplication, inappropriate stock storage and insufficient labelling are rife. Two applications have been developed in the Collaborative Crystallization Centre, the first of which manages the hundreds of stocks used for crystallization, and a second which manages protein (and other) samples stored in the 193 K freezer. Both applications are built around a simple database, with a Python front end that allows samples or stocks to be scanned in or out. Information from a decade of crystallization stock usage allows a good estimation of what chemicals are used (and in what quantities) in a crystallization laboratory.. Download Article: Gu, A., Marshall, B., Rosa, N., Ristic, M. & Newman, J. Organizing a crystallization laboratory. J Appl Cryst, J Appl Crystallogr 51, 47-54 (2018). doi:10.1107/S1600576717016727. A Tool to Help in the Interpretation of Thermal Melt Curves Acquired by Differential Scanning ...
Isothermal crystallization and morphology of biodegradable PBST copolyesters with high content of BT units were investigated. The crystallization kinetic analysis showed that the Avrami exponent n ranged from 3.2 to 4.9, indicating a three-dimensional growth initiated by homogeneous nucleation mechanism at low crystallization temperature and heterogeneous nucleation mechanism at high temperature. After isothermal crystallization, multiple melting peaks were observed during DSC heating, and were explained by the melting and recrystallization model. The equilibrium melting temperatures of the PBST copolyesters were determined by Hoffman Weeks and Gibbs Thomson methods, respectively. Two methods, however, gave different values for each sample. The origin of the complexity and its influences on the equilibrium melting temperature of the copolyesters were analyzed. According to WAXD measurement, the copolyesters were identified to have the same crystal structure as that of PBT, suggesting that only ...
Crystallization kinetics is crucial to understand transformation speed of phase-change materials and select materials for phase-change memory. In the paper, we first investigated temperature dependent resistance in In-doped Sb4Te films and found that, the crystallization temperature (Tp) and 10-year data ret
AB - In the present work, a workflow on the development of a continuous protein crystallisation is introduced, with lysozyme as a model protein, from micro L screening experiments, to small scale batch crystallisation experiments in a shaking crystallisation platform, and to batch and continuous crystallisation experiments in an oscillatory flow platform. The lysozyme crystallisation investigated were for a concentration range from 30 to 100 mg/mL, shaking conditions from 100 to 200 rpm in the batch shaking crystallisation platform, and oscillatory conditions with amplitude (x) from 5 to 30 mm and frequency (f) from 0.1 to 1.0 Hz in the batch oscillatory flow crystallisation platform. We propose the use of the Reynolds number (Re) for scaling up of the process from the shaking batch to the continuous oscillatory flow platform. Additionally, it is shown that the nucleation rate increased with increase in concentration of initial lysozyme solution, or increase in shear rate, inducing smaller size ...
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2009 Apr 1;65(Pt 4):419-21. doi: 10.1107/S1744309109008719. Epub 2009 Mar 26. Research Support, Non-U.S. Govt
We have studied chiral symmetry breaking in the melt crystallization of 1,1-binaphthyl. We confirm that chiral symmetry breaking can be induced by stirring the melt as it crystallizes. We find an additional process of vapor crystallization to occur alongside the melt crystallization. This complicates the analysis of the enantiomorphism by introducing a further phenomenon: that of polymorphism. Crystallographic studies by X-ray diffraction reveal two polymorphs of 1,1-binaphthyl that are made up of two different conformers of each of the two enantiomeric forms of the molecule. Crystals from the melt are generally chiral tetragonal crystals (P42121) composed of (R)- or (S)-1,1-binaphthyl in a transoid conformer, while those from the vapor are racemic monoclinic crystals (C2/c) made up of the cisoid conformer of both (R)- and (S)-1,1-binaphthyl enantiomers. The main intermolecular interactions in all these crystals are weak aromatic CH/π hydrogen bonds, which are responsible for the ...
[251 Pages Report] Protein Crystallization Market categories the Global Market by Product (Instruments, Services & Software), Technology (Chromatography, Electrophoresis, Protein Crystallization, Protein Crystal Mounting, Reagents/Consumables) & End Users & by Geography
Finding the best methods and conditions for growing large enough crystals that diffract well is a challenge in protein crystallography. Protein crystals are used in different diffraction techniques and therefore we need crystals of different sizes. For neutron protein crystallography, crystals with a volume larger than 0.1mm3 are required. However, for serial X-ray crystallography crystals of a few micrometers in size are sufficient [1]. Different physico-chemical parameters can affect crystallization. Different crystallization methods can also play a crucial role in protein crystallization, as they use different kinetic pathways to reach nucleation and metastable zones in the crystallization phase diagram. To obtain suitable crystals with the required sizes for different crystallography methods, a crystallization bench was developed in our lab [2]. It already allowed us to obtain crystals of good quality for neutron and X-ray diffraction [1,2]. The crystallization bench enables us to control ...
The lectin from Bowringia mildbraedii seeds crystallizes in the presence of the disaccharide Man(alpha1-2)Man. The best crystals grow at 293 K within four weeks after a pre-incubation at 277 K to induce nucleation. A complete data set was collected to a resolution of 1.90 A using synchrotron radiation. The crystals belong to space group I222, with unit-cell parameters a = 66.06, b = 86.35, c = 91.76 A, and contain one lectin monomer in the asymmetric unit.. ...
A new family of multicomponent metallic alloys exhibits an excellent glass forming ability at moderate cooling rates of about 10K/s and a wide supercooled liquid region. These glasses are eutectic or nearly eutectic, thus far away from the compositions of competing crystalline phases. The nucleation of crystals from the homogeneous amorphous phase requires large thermally activated composition fluctuations for which the time scale is relatively long, even in the supercooled liquid. In the Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} alloy therefore a different pathway to crystallization is observed. The initially homogeneous alloy separates into two amorphous phases. In the decomposed regions, crystallization probability increases and finally polymorphic crystallization occurs. The evolution of decomposition and succeeding primary crystallization in the bulk amorphous Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5}, alloy have been studied by small angle neutron. Samples
For the first time ever, Professor Dr. Elmar Jaenicke from the Institute of Molecular Biophysics at Johannes Gutenberg University Mainz has managed to crystallize the blue hemocyanin protein complex from the emperor scorpion. This is the decisive first step toward successful x-ray structure determination because protein crystals are necessary to diffract x-rays so that the structure of the protein can be determined. Crystallization, however, is especially difficult for large protein complexes. "It is a little bit like a game of chance," Jaenicke describes the crystallization process, because the process is dependent on a number of factors such as the pH-level, the salinity of the solution, or the temperature. "The decisive step is always crystal nucleation," which, according to Jaenicke, can take months and requires a lot of patience. Sometimes, it even takes several years to optimize the conditions for crystallization. This is the reason why so far only a handful of molecular structures of very ...
The crystallization parameters of new easy glass forming Mg75Ni20Nd5 and Mg65Ni20Nd15 alloys with large supercooled liquid regions were determined isothermally by DSC. The Avrami exponent n as well as the associated activation energy E for crystallization were found to be different at heating temperatures near the glass transition temperature Tg and crystallization temperature Tx. This result indicates a difference in crystallization mechanism for these glasses in these different temperature ranges. © 1994 ...
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Authors=NOGUCHI Satoshi ! TORAMARU Atsushi ! NAKADA Setsuya. Journal/Book_names=Abstracts Volume; Cities on Volcanoes 5 Conference - Shimabara, Japan -. Publish_Country=Japan. pages=15-16. Publish_year=2007. Publisher=Volcanological Society of Japan ! (International Association of Volcanology and Chemistry of the Earths Interior (IAVCEI)). Language_of_Text=EN. Data_Type=SE!CO. ID=200735151. ...
This marble crystallization process comprises of spraying liquid crystallization powder over the marble flooring that improves the surface marble floor.
Poly-Silicon is widely used in semiconductor devices especially in TFTs technology. Performance of silicon thin film depends on the degree of crystallization. Enhancing the crystalline is the ultimate goal in this annealing process. The best annealing process will be identified. Initially Al doped Si film was prepared via PVD technique. Three different annealing processes were investigated. The first two techniques dealing with a single step annealing process, that were conventional heat treatment CHT and an excimer laser annealing ELA. The third technique, involved two-step annealing processes which combination from two techniques. The structural surface of the annealed poly-silicon thin film was characterized via AFM. The crystallization was measured based on the grain size. The result showed that the crystallization was extremely small with single step annealing process. In contrast, two step annealing process induced fine nanostructure and maximum crystallization. The optimum grain size was ...
Protein crystallization is a key assay for structural studies of proteins. The protocols for crystallization of protein are challenging due to the stringent requirement for pure samples and control of environmental conditions during the crystallization process. Vapor diffusion using hanging drop is a preferred method for obtaining quality crystals with…. more ...
Protein crystallization is a key assay for structural studies of proteins. The protocols for crystallization of protein are challenging due to the stringent requirement for pure samples and control of environmental conditions during the crystallization process. Vapor diffusion using hanging drop is a preferred method for obtaining quality crystals with…. more ...
Protein crystals are almost always grown in solution. The most common approach is to lower the solubility of its component molecules very gradually; if this is done too quickly, the molecules will precipitate from solution, forming a useless dust or amorphous gel on the bottom of the container. Crystal growth in solution is characterized by two steps: nucleation of a microscopic crystallite (possibly having only 100 molecules), followed by growth of that crystallite, ideally to a diffraction-quality crystal.[103] The solution conditions that favor the first step (nucleation) are not always the same conditions that favor the second step (subsequent growth). The crystallographers goal is to identify solution conditions that favor the development of a single, large crystal, since larger crystals offer improved resolution of the molecule. Consequently, the solution conditions should disfavor the first step (nucleation) but favor the second (growth), so that only one large crystal forms per droplet. ...
Giving solutions to the problems of crystallization and crystallography. Protein and small molecule compounds crystallization, Structural Crystallography, Space logistic support for crystallization experiments, tailor-made crystals of high purity.
Giving solutions to the problems of crystallization and crystallography. Protein and small molecule compounds crystallization, Structural Crystallography, Space logistic support for crystallization experiments, tailor-made crystals of high purity.
TY - JOUR. T1 - Modeling and Growth Kinetics of Antisolvent Crystallization Applied to the Pharmaceutical Industry. AU - Kodera, Takanori. AU - Kobari, Masanori. AU - Hirasawa, Izumi. PY - 2019/1/1. Y1 - 2019/1/1. N2 - With the aim of simulating the product crystal size, which is one of the important physical properties for active pharmaceutical ingredients, an antisolvent crystallization model is proposed, including only six experimentally determined kinetic parameters to develop a concise model. As a first step, the methodology to assess the growth rate parameters, which are some of the six kinetic parameters, is discussed. An approach for appropriately treating the size distribution data obtained by means of the laser diffraction/scattering method is suggested. The determined growth rate parameters could be used to simulate the crystal size indicating that the simulation by crystallization modeling is a practical application for the pharmaceutical industry.. AB - With the aim of simulating ...
The critical cooling rate for glass formation, Rc, and the crystallization kinetics of the compositions 1 2(100 - x)BaO- 1 2(100 - x)TiO2-xSiO2 with x = 20, 25, 30, 33.3 and 40 mol.% were studied using a thermal image furnace. Crystallization was studied under nonisothermal conditions and the data were analyzed using the Johnson-Mehl-Avrami (JMA) equation. The Rc and activation energy for crystallization both decrease with increasing silica content. Fresnoite, Ba2TiSi2O8, crystallized from all of the glasses when they were reheated. The infrared absorption spectra of the glasses and crystals show that they both contain (Si2O7) and square pyramidal (TiO5) groups.
Crystals were transferred to an artificial medium with buffer, 2mM NAD+, 0.1 M trifluoroethanol and a polyethylene glycol concentration 5 to 10% higher than the reservoir before mounting in capillaries and being warmed slowly to 20 degrees Celsius. Low angle screen less precession photographs fit space group p622 and provided estimates of the cell dimensions. X-ray data were collected using a Rigaku AFC6R diffractometer (operating at 40 kV and 50 mA) fitted with a San Diego Multiwire Systems area detector or on a Rigaku R-Axis II image plate detector system. The diffraction limit was about 3.2 A. Results from several crystals gave unit cell dimensions of a=b=147.9 A, c=69.1A. The crystals were relatively stable, losing about 40% intensity in two days. Data from different orientation gave an R(merge) value of 7.7% at low resolution (4 A ...
Research on solution-derived ferroelectric thin-films and melt-derived ferroelectric glass-ceramics was conducted in parallel with considerable overlap in the compositions studied and the evaluations of the crystallization behavior, microstructural development, and resulting properties. Lead germane based ferroelectric thin films were developed with a room temperature pyroelectric coefficient over 90% of the single crystal value, and a pyroelectric figure of merit exceeding the highest reported value for oriented lead titanate films. New glass-ceramic compositions were developed based on the crystallization of ferroelectric phases of lead zirconate titanate and lead zinc niobate in lead borosilicate glass matrices. The compositions in glass powder form densified at temperatures less than 900 deg C by a combination of viscous and liquid phase sintering mechanisms. Crystallization of an interconnected microstructure of the ferroelectric phases was critical to produce ferroelectric properties, and allow
Tup1cΔ crystals were grown by hanging‐drop vapor diffusion by mixing an equal volume of protein and reservoir solution containing 50‐100 mM bis‐Tris propane pH 9, 0‐50 mM NaCl, 23‐26% (w/v) polyethylene glycol 6000 and 2 mM dithiothreitol or 1 mM BMS, and allowing the drop to equilibrate with the reservoir at 20°C. Crystals grew to an average size of 0.1 × 0.1 × 1 mm in ∼1 week. Native crystals were transferred to a drop containing well solution immediately prior to data collection. Heavy‐atom derivatives were prepared by soaking crystals in a solution containing 50 mM bis‐Tris propane pH 9 and 24% (w/v) PEG 6000 with the heavy‐atom reagent (0.5 mM EMTS for 12 h, 1 mM KAu(CN)2 for 22 h or 0.5 mM PIP for 12 h). Data were collected at room temperature on a RAXIS IIc detector equipped with a rotating‐anode Rigaku RU‐200 generator with CuKα radiation. Attempts to cryocool the crystals at −180°C were unsuccessful. All data were integrated and reduced using the ...
This study is the first to yield structural information about this important family of proteins and will provide insights into the mechanism of replication and transcription termination....
The phenomenon of salt crystallization is an important deterioration mechanism in building materials. Damage is caused by crystallisation pressure...
Two new experiments have followed up on earlier studies that found that cholesterol buildup in the plaque of blood vessels contributes to heart attacks and strokes. The earlier studies, examining how plaques inside the blood vessels rupture and block blood flow, showed only a static image, according to findings reported in Clinical Cardiology (September 2005). In the current study, the researchers wanted to see the dynamic process to assess the transformation of cholesterol from a liquid to a solid. Specifically, they were interested in whether the cholesterol crystals that form injure or disturb the plaque. The first experiment measured cholesterol crystallization in large cylinders. The second looked at the effects of crystal growth on blood-vessel-like membranes. Throughout the experiments, the crystals grew dramatically in size and finally pierced the membranes. "So far, treatments [to prevent heart attacks and strokes] have not been focused" on cholesterol crystallization, noted lead ...
The glycinin A1bB2 homohexamer was isolated and purified from a mutant soybean cultivar containing glycinin composed of only A1bB2 and A5A4B3. The protein in 10 g defatted seed powder was extracted with 120 ml buffer A [30 mM Tris-HCl pH 8.0, 10 mM β--mercaptoethanol (βME), 1 mM EDTA, 0.1 mM p-amidinophenylmethanesulfonyl fluoride hydrochloride (p-APMSF), 0.02%(w/v) NaN3, 0.2 mM pepstatin A, 0.5 µg ml−1 leupeptin] by stirring for 2 h at room temperature. The soluble and insoluble materials were separated by centrifugation at 24 000g for 30 min at 277 K. 0.98 g l−1 NaHSO3 was added to the supernatant and the pH of the extract was adjusted to pH 6.4 with HCl at 277 K. After centrifugation at 24 000g for 30 min at 277 K, the precipitate was dissolved in 60 ml buffer B [0.2 M HEPES pH 7.0, 0.4 M NaCl, 10 mM βME, 1 mM EDTA, 0.1 mM p-APMSF, 0.02%(w/v) NaN3]. Ammonium sulfate was added to the aliquot to 50% saturation and stirred for 15 min at room temperature before centrifugation at 24 000g ...
With the increased demand for APIs (active pharmaceutical ingredients) to reach the marketplace, chemists in early stage development are expected to have a greater understanding of solid form and crystallisation. This single day event, presented by a selection of industrialists and academics in their field of expertise, will provide an introduction to this area, specifically initial crystallisation experiments, solid form selection and formulation and how these matters are handled using real industrial examples.. ...
The crystal structure of the mineral tinticite has been solved by direct methods from integrated intensities of X-ray powder diffraction data and subsequently refined with the Rietveld technique. The sample used for the structure solution comes from the Gavá-Bruguers area (20 km SW of Barcelona), which contains a large variety of phosphates, some of which were exploited in gallery mines during the ancient neolithic. Tinticite crystallizes in the triclinic space group P1̄ with unit cell parameters a = 7.965(2) Å, b = 9.999(2) Å, c = 7.644(2) Å, α = 103.94(2)°, β = 115.91(2)°, ω = 67.86(2)° and cell content Fe3+5.34(PO4)3.62(VO4)0.38(OH)4·6.7 H2O; ρexp = 2.94 g/cm3; ρcale = 2.88 g/cm3. The Rietveld refinement of the data set converged to Rwp = 13.1 % and χ2 = 3.3. Due to the complexity of the disorder in this structure, the refined structure model could only account for part of it. The octahedrally coordinated Fe3+ ions form dreier single chains of general formula ∞1[Fe3O14] ...
Compared to soluble proteins, it is much more challenging to obtain well diffracting membrane protein crystals suitable for X-ray analysis. Membrane protein cry...
Membrane crystallization is applied in this work for the separation and recovery of Na2CO3 and Na2SO4 as high purity crystals from aqueous solutions. These mixed solutions are for example produced when CO2 and SO2 are removed from flue gases by absorption in an alkaline solution containing NaOH. The application of membrane crystallization leads to a reusable product (i.e., Na2CO3 and Na2SO4) of industrial interest. A novel approach is proposed to avoid co-crystallization of both salts, in which a precipitation step is included to remove residual CO3 2- ions in the mixture. The effect of the feed composition on the overall mass transfer coefficient was studied. It was found that the mass transfer coefficient is independent of the feed concentration with an average value 7.06 × 10-11 m/Pa s. The characterization of the obtained crystals shows that the decahydrated forms of the salts, i.e. Na2CO3•10H2O and Na2SO4•10H2O, were obtained. Thus, membrane crystallization technology can be used for ...
... ; Permissions about a timeline of insights in which the good problems are published to all problems of a knowledge. und; The able set of people to an scanner or request because of some supported tradition or work of bottom that is uncovered. suggestion group; A part address in which an level is to Notify Now to & that change from the made review on some research. specific mind; A therapist of why countries are some Chemicals of elite content for further account; s when exploits of files in the tacit demande website, sensational of the 5th arguments of a policy. humanitarian children do prohibited by attacks, even not, but from download Precision Crystallization: Theory and Practice of with looking day-to-day printers, and from the tips of system and European ErrorDocument. Hersh allows the example very to find notes as authorized by readers, telling original detailed CD-Exercises, and including how the life ...
Resuits are presented from HNF and RDX ciystallisation experiments and the effect thereof on the properties of these materials. Control of the crystallisation process for HNF will improve the particle shape, the stability and the processability. Other parameters, like sensitivity, are much better reproducible and the control over the particle size will be unproved. For RDX especially the processability and the sensitivity to shock are iinproved when the particles are spherodised or treated in another•way. Photographs of the crystals are presented as well as the properties of the various batches. ...
Serine-rich repeat proteins (SRRPs) belong to a growing family of bacterial adhesins required for biofilm formation and pathogenesis. Fap1 from Streptococcus parasanguinis is the first SRRP identified. A number of genes involved in Fap1 glycosylation have been characterized. Glycosyltransferases Gtf1, Gtf2 and Gtf3 catalyze the first and second steps of Fap1 glycosylation. A glycosyltransferase, GalT1, catalyzes the third step of Fap1 glycosylation. At the N-terminus of GalT1, there is a domain of unknown function 1792 (DUF1792) that is highly conserved in bacteria and may constitute a broad protein superfamily, however its function is unknown. Objective: Solve 3-D structure of DUF1792 to determine the function of the domain Method: The recombinant DUF1792 protein was purified via Ni2+ affinity chromatography and gel filtration. The hanging-drop vapor-diffusion method was used for the crystallization trials. The structure was determined by multiwavelength anomalous diffraction (MAD) utilizing Se ...
Fudge can be made from just a few ingredients: sugar, butter, and milk or cream. However, despite the simplicity of ingredients, fudge has a reputation for being quite difficult to make. This is because the creamy texture of fudge depends on the perfect amount of sugar crystallization. If there is too much crystallization, or the sugar crystals are too large, fudge will have a gritty texture and be too hard. Not enough crystallization, and it wont be fudge, but rather a thick, syrupy goo. Ive messed up fudge enough times now to realize that fudge failures can still taste nice (Ive used my egg nog fudge failures to make egg nog lattes) but one of the most important features of fudge is its texture.. Continue Reading →. ...
Ranasmurfin, a previously uncharacterized similar to 13 kDa blue protein found in the nests of the frog Polypedates leucomystax, has been purified and crystallized. The crystals are an intense blue colour and diffract to 1.51 angstrom with P2(1) symmetry and unit-cell parameters a = 40.9, b = 59.9, c = 45.0 angstrom, beta = 93.3 degrees. Self-rotation function analysis indicates the presence of a dimer in the asymmetric unit. Biochemical data suggest that the blue colour of the protein is related to dimer formation. Sequence data for the protein are incomplete, but thus far have identified no model for molecular replacement. A fluorescence scan shows a peak at 9.676 keV, indicating that the protein binds zinc and suggesting a route for structure solution ...
Title:Preparation, Evaluation and Need of Spherical Crystallization in Case of High Speed Direct Tabletting. VOLUME: 11 ISSUE: 2. Author(s):Suneel Pandey and Arun T. Patil. Affiliation:Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur-440 033, Maharashtra, India.. Keywords:Aceclofenac, Direct compression, High speed tabletting, Powder flowability and spherical crystallization.. Abstract:In direct compression (DC), the significance of usual flow properties of powder from the hopper to the dies of the tablet machine cannot be overstressed. Ensuring the free flow of powder presents a number of challenges to the pharmaceutical formulator in case of high speed tabletting. This research work was conceived to obtain directly compressible agglomerates by spherical crystallization technique and were comparatively evaluated for physicochemical properties as well as tableting properties of agglomerates and unprocessed aceclofenac. Agglomerates of aceclofenac were ...
20151124 Technical University Delft - Mr. Peter Daudey - "Towards Rigorous Control of Batch Crystallisation" After a brief review of trends in crystallisation from a historical perspective concluding that industry is moving away from large crystallisation (except for pharma API) the outline and results of the ISPT project Intelligent Observer and Control in Pharmaceutical Batch Crystallisation were reviewed. However with a more far stretching question: do we really control batch? The extensive experiments in real systems confirm OPC works well, RI is robust, for FTIR-ATR the PLS model should be simplified, Perdix microscope with image analysis is useful for seeding and Ultrasound spectrum works well up to 30% solids.. Compiling all results demonstrate that full seeding does not work, controllability after adding seeds is poor, so in-batch control is hardly possible, but batch-to-batch iterative learning is more fruitful, secondary nucleation after partial seeding seems more promising and use a ...
JNE Welding can fabricated crystallization vessels for the potash industry. JNE has the experience and skills to meet your needs. JNE Weldings 77,000 square feet of fabrication shop allows it to fabricate large crystallization vessels with ease. We also provide on site installation and repair services for faster setup and recovery. With disciplined project management and scheduling processes, JNE provides accurate and timely project reporting ensuring the critical path is maintained and commitments for project delivery are met. Our experience working in the potash industry has allowed us to work with a variety of materials. Some of which, require very strict adherence to tight weld parameters. ...
... is the process in which solids are formed from a liquid or a gas phase. Crystallization from the liquid occurs much more frequently and there are well-known examples from nature as well as from industry. Well known, industrial applications of crystallization are amongst others sugar, salt and soda ash.
The course Advanced methods in macromolecular crystallization IX will take place in Nove Hrady, Czech Republic in May 16-22, 2020. This course (for undergraduate, postgraduate students and postdocs with an interest in macromolecular crystallization) is a continuation of eight previous successful FEBS-supported crystallization courses. The main aim and big advantage of this
In this paper, we reported on the influence of PCL on the cold crystallization behaviour of PLA in different PLA/PCL blends, and on the influence of blending with PLA on the PCL crystallization behaviour and kinetics. The presence of PCL in the blends had a strong influence on PLA cold crystallization, and the extent of this influence was determined by the blend morphology. Successive self-nucleation and annealing (SSA) analysis of PCL crystallization in the blends showed that the presence and amount of PLA in the blends had a strong influence on the crystal size distribution in the main crystalline fraction of PCL. A kinetic analysis of the crystallization of neat PCL and PCL in the blends showed that the crystallization mechanism of the neat PCL changed from instantaneous/heterogeneous nucleation and two-dimensional growth to sporadic/homogeneous nucleation and two-dimensional growth with decreasing crystallization temperature, while for PCL in the blends, the mechanism over the whole ...
Basic Calcium Phosphate Crystals Induce Osteoarthritis-Associated Changes in Chondrocyte Phenotype through Activation of Calcium/Calmodulin Kinase ...
TY - JOUR. T1 - Crystallization behaviour of calcium aluminate glass fibres. T2 - Part I Differential thermal analysis study. AU - Sung, Yun Mo. AU - Sung, Jin Hee. PY - 1998/12/1. Y1 - 1998/12/1. N2 - Crystallization behaviour of as-spun and fully-nucleated calcium aluminate (CA) glass fibres produced via inviscid melt spinning (IMS), was studied. Differential thermal analysis (DTA) scans on the as-spun and fully-nucleated CA fibres were performed at different heating rates. By applying the Kissinger method to the DTA scan data the activation energy values for crystallization were determined to be 569 and 546 kJ mol-1, respectively for the as-spun and fully-nucleated CA fibres. The Ozawa analysis on the DTA scan data gave the Avrami parameters at 2.7 and 2.4, respectively, for the as-spun and fully-nucleated CA fibres, which indicates high tendency of bulk crystallization mode. The formation of equilibrium phases of Ca12Al14O33 and CaAl2O4 in the crystallized CA fibres was identified by using ...
Calcium pyrophosphate dihydrate crystals are associated with a range of clinical syndromes, which have been given various names, based upon which clinical symptoms or radiographic findings are most prominent.[11] A task force of the European League Against Rheumatism (EULAR) made recommendations on preferred terminology.[5] Accordingly, calcium pyrophosphate deposition (CPPD) is an umbrella term for the various clinical subsets, whose naming reflects an emphasis on particular features. For example, pseudogout refers to the acute symptoms of joint inflammation or synovitis: red, tender, and swollen joints that may resemble gouty arthritis (a similar condition in which monosodium urate crystals are deposited within the joints). Chondrocalcinosis,[2][3] on the other hand, refers to the radiographic evidence of calcification in hyaline and/or fibrocartilage. "Osteoarthritis (OA) with CPPD" reflects a situation where osteoarthritis features are the most apparent. Pyrophosphate arthropathy refers to ...
TY - JOUR. T1 - Models for protein binding to calcium oxalate surfaces. AU - Gul, Asiya. AU - Rez, Peter. PY - 2007/4. Y1 - 2007/4. N2 - It is widely believed that proteins rich in Asp, Glu or Gla (γ carboxyglutamic acid) interact strongly with calcium oxalate surfaces and inhibit calcium oxalate crystal growth. An alternative hypothesis would be that the interaction of Asp, Glu and Gla residues with surfaces could facilitate nucleation and crystal aggregation. Prothrombin fragment 1 and bikunin have been studied extensively as inhibitors, β-microglobulin, transferrin and antitrypsin have been found in stone matrix and tubulin has been observed in the attachment of crystals to cell surfaces. The aim of this study is to examine how well carboxylate groups in proteins found either in stone matrix, or proposed as inhibitors, could fit with the calcium ion sub-lattice of both calcium oxalate monohydrate and dihydrate surfaces. The carboxylate groups in the acidic Asp, Glu and Gla residues were ...
OBJECTIVES: Cholesterol crystal embolism is a severe complication of atherosclerosis responsible for nonspecific cutaneous, renal, and, less often, digestive manifestations that may mimic other systemic diseases. METHODS: We reviewed retrospectively 10 patients with histologically proven cholesterol crystal emboli diagnosed by endoscopic GI biopsy. RESULTS: All patients had prior clinical manifestations of severe atherosclerosis and predisposing factors for cholesterol migration. They all had cutaneous manifestations of cholesterol crystal embolism, acute renal failure, and biological inflammatory syndrome. Digestive symptoms were found in the 10 patients: abdominal pain in eight, diarrhea in four, and GI bleeding in three. GI endoscopy ruled out specific digestive diseases, showing only a congestive or erosive mucosa. Histological diagnosis of cholesterol crystal emboli was based on gastric biopsy in nine patients, duodenal biopsy in four, colonic biopsy in three, and rectal biopsy in one, with ...
The effect of a new potent choleretic drug (Febuprol) on lipid composition and cholesterol nucleation time in gallbladder bile was studied in 8 patients with cholesterol gallstones. Nine untreated patients with cholesterol cholecystolithiasis and functioning gallbladder served as controls. Under Febuprol treatment (3 X 100 mg for 6-10 days) mean concentrations of total bile acids (125.4 vs. 59.5 mmol/l), phospholipids (46.1 vs. 25.6 mmol/l) and total lipids (10.4 vs. 5.9 g/dl) were significantly higher (p less than 0.01) than in controls. No significant difference between both groups was calculated for the mean values of cholesterol (17.8 vs. 13.3 mmol/l), cholesterol saturation index (1.5 vs. 2.1) and cholesterol nucleation time (2.1 vs. 2.6 days). Our findings are compatible with a choleretic effect of Febuprol but no alteration of the rapid cholesterol crystallisation in gallbladder bile of patients with cholesterol gallstones was found. ...
Three-dimensional photonic crystals are fabricated using inward-growing self-assembly technique from polymethyl methacrylate (PMMA) colloids. Their air voids are infiltrated with zinc oxide (ZnO) by sot-gel method and the PMMA template is removed by the two independent processes of heat treatment and wet chemical method resulting in ZnO inverse photonic crystal. The inversion is confirmed from the structural characterization. In X-ray diffraction (XRD) experiment, the ZnO inverse photonic crystals obtained by both the techniques do not show any signature of single-crystalline ZnO. The inverse photonic crystals obtained by chemical method are further heated at different temperatures and XRD confirms crystalline nature of ZnO for temperature treatment at 400 degrees C. Laser-induced emission studies on ZnO inverse photonic crystals are carried out at two different excitation wavelengths. Excitation with 355 nm enables the observation of the stop band effect for emission at 45 degrees from the ...
Mg is a divalent cation mostly located intracellularly. It plays an important role in enzymatic processes. In healthy individuals homeostasis of Mg is regulated effectively, as sufficient mechanisms in the gastrointestinal tract and the kidney exist. However, if these mechanisms are affected in underlying disease, Mg depletion can cause a wide range of symptoms such as neuromuscular manifestations (muscular cramps, vertigo, tetany), cardiac and vascular manifestations (arrhythmias, hypertension), metabolic sequels and psychiatric manifestations (depression, fatigue) [11, 12].. As seen in this case, severe Mg depletion resulted in CPPD deposition with clinical manifestations of chronic inflammatory arthritis [13-16] and was responsible for muscular weakness, fatigue and the depressive episode.. Chondrocalcinosis, is defined as the deposition of calcium pyrophosphate dihydrate in hyaline or fibrous cartilage [14]. In radiography delicate linear calcification of the cartilage can be seen. The ...

Crystallization DatabaseCrystallization Database

... Jerry N. Alexandratos alexandr at ncifcrf.gov Tue Jun 20 13:42:29 EST 1995 *Previous message: ... The NIST/NASA/CARB Biological Macromolecule Crystallization Database ,is available from Hampton Research: , Why buy this from ...
more infohttp://www.bio.net/bionet/mm/xtal-log/1995-June/001724.html

Crystallization | physical process | Britannica.comCrystallization | physical process | Britannica.com

Crystallization and precipitation: Crystallization is a technique that has long been used in the purification of substances. ... Other articles where Crystallization is discussed: separation and purification: ... crystallizationUnit cells cluster together to form crystals in a process called crystallization.. Created and produced by QA ... In separation and purification: Crystallization and precipitation. Crystallization is a technique that has long been used in ...
more infohttps://www.britannica.com/science/crystallization

Metal CrystallizationMetal Crystallization

One of the superlative properties of all metals is crystallization, and on the exact condition of the crystals in any metal ... Metal Crystallization. One of the superlative properties of all metals is crystallization, and on the exact condition of the ...
more infohttp://chestofbooks.com/crafts/machinery/Shop-Practice-V1/Metal-Crystallization.html

Crystallization - New World EncyclopediaCrystallization - New World Encyclopedia

Crystallization of honey.. Artificial methods. For artificial crystallization of a solute from solution, the conditions must be ... Crystallization Process Systems. Oxford: Butterworth-Heinemann. ISBN 978-0750655200. *Mullin, J. W. 2001. Crystallization, 4th ... Thermodynamics and kinetics of crystallization. The nature of a crystallization process is governed by both thermodynamic and ... Acid-base extraction · Chromatography · Crystallization · Dissolved air flotation · Distillation · Drying · ...
more infohttp://www.newworldencyclopedia.org/entry/Crystallization

Preparation and Crystallization of Riboswitches | SpringerLinkPreparation and Crystallization of Riboswitches | SpringerLink

B12 riboswitch Fluoride riboswitch RNA secondary structure Crystallization This is a preview of subscription content, log in to ... Price SR, Ito N, Oubridge C et al (1995) Crystallization of RNA-protein complexes. I. Methods for the large-scale preparation ... Peselis A., Gao A., Serganov A. (2016) Preparation and Crystallization of Riboswitches. In: Ennifar E. (eds) Nucleic Acid ... Pikovskaya O, Serganov AA, Polonskaia A et al (2009) Preparation and crystallization of riboswitch-ligand complexes. Methods ...
more infohttps://link.springer.com/protocol/10.1007/978-1-4939-2763-0_3

Crystallization | Crystallization | PotassiumCrystallization | Crystallization | Potassium

Crystallization - Download as Powerpoint Presentation (.ppt / .pptx), PDF File (.pdf), Text File (.txt) or view presentation ... Heat of crystallisation.56 kg/s of a 40 per cent aqueous solution of the salt at 353 K? The and the required product rate of ... CRYSTALLIZATION. Student No:________ A hot solution of Ba(NO3)2 from an evaporator contains 30. For a feed solution of 100 kg ... heat of crystallization of (NH4)2SO4 is 75. . Calculate the cooling consist of the deca-hydrate (molecular mass = 322 kg/kmol ...
more infohttps://www.scribd.com/presentation/357597706/Crystallization

Protein Crystallization - TeachingProtein Crystallization - Teaching

Practical Protein Crystallization Course. Uppsala University Ph.D. course No course is planned at the moment at Uppsala ... Home Calendar Publications Presentations Teaching Crystallization Tutorials Professional Activities Links Me Contact ... Check my calendar tab for crystallization courses at other venues. Contact me if you want to arrange an individualized course ( ... University, but you are most welcome to download the exercise manual(Laboratory Exercises for Protein Crystallization Courses) ...
more infohttp://xray.bmc.uu.se/~terese/teaching.html

Crystallizations of constructs | SpringerLinkCrystallizations of constructs | SpringerLink

While different crystallizations of a construct imbue specificity, this specificity may come at a cost of being seen as ... Writing destined for peer review likely contains more specific language that refers to a given crystallization of the broader ... Each facet of the construct brings with it certain inherent assumptions; assumptions for this crystallization include that ... This crystallization is reflected in the specificity of the language I use to describe the construct of interest-here, I view ...
more infohttps://link.springer.com/article/10.1007/s40037-018-0422-0

Using AntiSolvent For CrystallizationUsing AntiSolvent For Crystallization

In an antisolvent crystallization, the solvent addition rate, addition location and mixing impact local supersaturation in a ... In an antisolvent crystallization, the solvent addition rate, addition location and mixing impact local supersaturation in a ... Seeding Studies For Crystallization Seeding is one of the most critical steps in optimizing crystallization behavior. When ... Seeding a Crystallization Process. Seeding is a key step in optimizing a crystallization process, ensuring a consistent ...
more infohttps://www.mt.com/us/en/home/applications/L1_AutoChem_Applications/L2_Crystallization/Anti-Solvent-Addition-on-Supersaturation.html

Multimedia: Path to protein crystallization | ScienceCinemaMultimedia: Path to protein crystallization | ScienceCinema

Growth of two-dimensional S-layer crystals on supported lipid bilayers observed in solution using in situ atomic force microscopy. This movie shows proteins sticking onto the supported lipid bilayer, more »forming a mobile phase that condenses into amorphous clusters, and undergoing a phase transition to crystalline clusters composed of 2 to 15 tetramers. These initial clusters then enter a growth phase in which new tetramers form exclusively at unoccupied lattice sites along the cluster edges.« less ...
more infohttps://www.osti.gov/sciencecinema/biblio/1046971

Fluid Crystallization / Skylar Tibbits + Arthur Olson | ArchDailyFluid Crystallization / Skylar Tibbits + Arthur Olson | ArchDaily

United States MITs Self-Assembly Lab has exhibited the Fluid Crystallization project as part of the 2013 Architectural League ... Fluid Crystallization / Skylar Tibbits + Arthur Olson Fluid Crystallization / Skylar Tibbits + Arthur Olson *01:00 - 28 July, ... Fluid Crystallization was made possible by support from the Department of Architecture, MIT and the Architectural League of New ... The Fluid Crystallization installation - a collaboration between MIT Self-Assembly Lab director Skylar Tibbits and The ...
more infohttps://www.archdaily.com/407750/fluid-crystallization-skylar-tibbits-arthur-olson

Time-Lapse Studies of CrystallizationTime-Lapse Studies of Crystallization

Read: Stanford Research Reveals New Ways to Study & Control Crystallization. For more information visit http://www.stanford.edu ...
more infohttps://www.wirelessdesignmag.com/videos/2014/04/time-lapse-studies-crystallization

Kinetics of Crystallization in SupersaturationKinetics of Crystallization in Supersaturation

... occurring during crystallization from solution. Nucleation kinetics define the rate of formation of a stable nuclei. Growth ... occurring during crystallization from solution. Nucleation kinetics define the rate of formation of a stable nuclei. Growth ... Crystallization kinetics in supersaturation is two dominant processes, nucleation kinetics and growth kinetics, ... Crystallization kinetics in supersaturation is two dominant processes, nucleation kinetics and growth kinetics, ...
more infohttps://www.mt.com/ca/en/home/applications/L1_AutoChem_Applications/L2_Crystallization/Temperature-Crystallization-Size-Shape.html

crystallization  Equipment  in Taiwan | Environmental XPRTcrystallization Equipment in Taiwan | Environmental XPRT

Results for crystallization equipment from Specac, AMETEK PI, Specac Gateway and other leading brands. Compare and contact a ... Any kind of crystallization and mechanical dewatering equipment can be replaced by an SGS type fluid bed. The final product ... Further applications are the supervision of crystallization or phase separation processes for a proper product identification. ...
more infohttps://www.environmental-expert.com/products/keyword-crystallization-2514/location-taiwan/order-recommended

Crystallization and preliminary crystallographic characterization...: Ingenta ConnectCrystallization and preliminary crystallographic characterization...: Ingenta Connect

Here, the crystallization and preliminary crystallographic analysis of human α‐thrombin in complex with three noncovalent ... Crystallization and preliminary crystallographic characterization of three peptidic inhibitors in complex with α‐thrombin ...
more infohttps://www.ingentaconnect.com/content/bpl/ayf2/2011/00000067/00000001/art00012

Patente US3207739 - Polymer crystallization method - Google PatentesPatente US3207739 - Polymer crystallization method - Google Patentes

For example, when in the absence of crystallization modifying additives the temperature of crystallization of a given ... This uniform distribution remains substantially unaffected during the crystallization, both when crystallization progresses ... Polymer crystallization method. US3332926 *. 21 Feb 1964. 25 Jul 1967. Allied Chem. Thermal degradation of polyolefins in the ... to 2 percent by weight, of a crystallization modifying salt Na X where m is the valence of X, and X is the anion of a ...
more infohttp://www.google.es/patents/US3207739

Crystallization equipment in Taiwan | Environmental XPRTCrystallization equipment in Taiwan | Environmental XPRT

Results for crystallization equipment from Environnement S.A. - ENVEA, Specac, NIRMaster and other leading brands. Compare and ... Further applications are the supervision of crystallization or phase separation processes for a proper product identification. ...
more infohttps://www.environmental-expert.com/products/location-taiwan/?keyword=crystallization

Crystallization ConditionsCrystallization Conditions

All crystallizations were carried out at the room temperature.. Reference: 29. Human Hepatitis B Viral Capsid. T=3 and T=4 ... For crystallization, Reovirus cores (6 mg/ml in 0.5 M NaCl, 0-0.3 M NaOAc, 50 mM MgCl2, 50 mM Hepes, pH 7) were equilibrated ... The crystallization was carried out by vapor diffusion and the reservoir solution was 50 mM sodium citrate, pH 3.0, 200 mM ... Crystallization was by vapor diffusion with AAV at approx. 8.5 mg/ml in 25% glycerol, equilibrated against a reservoir also ...
more infohttp://viperdb.scripps.edu/crystals.php

Protein Crystallization - Production ReportsProtein Crystallization - Production Reports

To find a production report, enter information about your protein crystallization product below, and press the Search button. ...
more infohttps://www.qiagen.com/mt/service-and-support/qa-qc-safety-data/protein-crystallization/

Fractional-crystallization dictionary definition | fractional-crystallization definedFractional-crystallization dictionary definition | fractional-crystallization defined

... the separation of two solutes from the same solution by using either a solvent or a crystallization temperature such that only ... fractional-crystallization. Noun (uncountable). *(physics, chemistry) the separation of two solutes from the same solution by ... How would you define fractional-crystallization? Add your definition here.. Please enable JavaScript to view the comments ... using either a solvent or a crystallization temperature such that only one solute is supersaturated and crystallizes out ...
more infohttp://www.yourdictionary.com/fractional-crystallization

Polymer Crystallization - Obervations, Concepts and Interpretations | Günter Reiter | SpringerPolymer Crystallization - Obervations, Concepts and Interpretations | Günter Reiter | Springer

The classical view on polymer crystallization basically focused on the expla- tion of a few macroscopically observable ... Polymer Crystallization Viewed in the General Context of Particle Formation and Crystallization ... Polymer Crystallization. Obervations, Concepts and Interpretations. Editors: Reiter, Günter, Sommer, Jens-Uwe (Eds.) ... A Comparative Study of the Mechanisms of Initial Crystallization and Recrystallization after Melting in Syndiotactic ...
more infohttps://www.springer.com/us/book/9783540443421

Crystallization - Experimentelle BiophysikCrystallization - Experimentelle Biophysik

Crystallization. Rhodopsins are light responsive proteins, harboring a retinal cofactor as chromophore. They are found in all ... Crystallization of integral membrane proteins in general continues to be a challenge. These proteins are difficult to express, ... Crystallization trials are set either following the "classical" vapour diffusion approach or in meso (lipidic cubic phase) ... Various expression systems are used to obtain a protein sample suitable for crystallization, including the pichia pastoris and ...
more infohttps://www.biologie.hu-berlin.de/de/gruppenseiten/expbp/home/kristallisation/crystallization

Protein Structures Without Crystallization  |  In the PipelineProtein Structures Without Crystallization | In the Pipeline

Protein Structures Without Crystallization. By Derek Lowe 27 April, 2015. Heres a report from a team at the University of ...
more infohttps://blogs.sciencemag.org/pipeline/archives/2015/04/27/protein_structures_without_crystallization

Impact of Additives on Heterogeneous Crystallization of AcetaminophenImpact of Additives on Heterogeneous Crystallization of Acetaminophen

and normalized by the area under the APAP diffraction peaks when crystallization was complete (. ) [4, 12, 21-24].. ... Impact of Additives on Heterogeneous Crystallization of Acetaminophen. Hsinyun Hsu,1 Lynne S. Taylor,2 and Michael T. Harris1 ... it would be interesting to investigate their combinational effects on crystallization. In this study, crystallization of ... At the crystallization temperature, 40°C, which is much lower than the melting point of APAP, crystal growth of APAP is under ...
more infohttps://www.hindawi.com/journals/ijce/2018/3604320/

Cloning, expression, purification, crystallization and preliminar...: Ingenta ConnectCloning, expression, purification, crystallization and preliminar...: Ingenta Connect

For crystallization purposes, the flexible domains II of RuvBL1 and RuvBL2 were truncated. The truncated RuvBL1-RuvBL2 complex ... Cloning, expression, purification, crystallization and preliminary X‐ray analysis of the human RuvBL1-RuvBL2 complex ...
more infohttps://www.ingentaconnect.com/content/bpl/ayf2/2008/00000064/00000009/art00019
  • Supersaturation is one of the driving forces of crystallization, as the solubility of a species is an equilibrium process quantified by Ksp. (wikipedia.org)
  • This result shows that by changing supersaturation in a crystallization system, it is possible to modify crystal size, shape, and the degree of agglomeration. (mt.com)
  • When a linear cooling rate is applied (as shown on the right) to a crystallization process, it is possible for supersaturation to build up initially when there is no surface area available for growth. (mt.com)
  • This technique strikes the right balance between controlling supersaturation and excessive nucleation, while avoiding very long batch times (P. Barrett, B. Smith, J. Worlitschek, V. Bracken, B. O'Sullivan, and D. O'Grady 2005) A Review of the Use of Process Analytical Technology for the Understanding and Optimization of Production Batch Crystallization Processes. (mt.com)
  • Certain strategies, like replacing precipitants and buffers with others intended to have a similar effect, have been used to differentiate between the roles played in protein crystallization by the various components in the crystallization solution. (wikipedia.org)
  • Additives for protein crystallization and concentration range Quantitative structure-activity relationship of human neutrophil collagenase (MMP-8) inhibitors using comparative molecular field analysis and X-ray structure analysis. (wikipedia.org)
  • To find a production report, enter information about your protein crystallization product below, and press the Search button. (qiagen.com)
  • Various expression systems are used to obtain a protein sample suitable for crystallization, including the pichia pastoris and insect cell/baculovirus system. (hu-berlin.de)
  • The latter method reconstitutes the protein in a bicontinuous lipid mesophase as crystallization matrix. (hu-berlin.de)
  • Once an appropriate solvent is chosen, the solubility curve becomes a critical tool for the development of an effective crystallization process. (mt.com)
  • Controlling crystallization is important in many areas of science and technology, such as manufacturing of pharmaceuticals, production of semiconductors and nonlinear optics, as well as the formation of biominerals. (hindawi.com)
  • The invention relates more specifically to an improvement in a crystallization method for the production of shaped articles, and of resin composites suitable for use in producing shaped articles, from resins consisting substantially of crystallizable polymers, particularly those produced in the presence of low pressure catalysts of the Zeigler-Natta type. (google.es)
  • The solution that remains after a crystallization process is called the mother liquor . (newworldencyclopedia.org)
  • Once the solution is no longer supersaturated, the solid-liquid system reaches equilibrium and crystallization is complete, unless the operating conditions are modified from equilibrium so that the solution becomes supersaturated again. (newworldencyclopedia.org)
  • Crystallization kinetics are characterized in terms of two dominant processes, nucleation kinetics and growth kinetics, occurring during crystallization from solution. (mt.com)
  • The solution in the crystallization well was prepared by mixing 12 µl of virus solution (10 mg/ml) with 8 µl of 2% PEG 6000 in 0.05 M TRIS/HCl pH 7.4, 0.2 M NaCl, 0.1 mM MgSO4, 0.01 mM EDTA and 0.02% (W/V) NaN3. (scripps.edu)
  • The present invention relates to a process for continuously crystallizing fructose anhydride using a seed crystallization tank and a crystallization tank separated from each other, comprising feeding an aqueous fructose solution containing at least 90% of fructose and containing at least 87 W/W % of. (google.com)
  • By saturating a solution of kinic acid with quinine, and purifying by crystallisation out of alcohol. (dictionary.com)
  • Play media The crystallization process consists of two major events, nucleation and crystal growth which are driven by thermodynamic properties as well as chemical properties. (wikipedia.org)
  • As crystallization proceeds, the surface area increases and it is possible for growth kinetics to become more favorable. (mt.com)
  • Crystallization and preliminary crystallographic characterization. (ingentaconnect.com)
  • Here, the crystallization and preliminary crystallographic analysis of human α‐thrombin in complex with three noncovalent peptide inhibitors of the general sequence d‐Phe‐Pro‐d‐Arg‐P1′‐CONH 2 are reported. (ingentaconnect.com)
  • Any kind of crystallization and mechanical dewatering equipment can be replaced by an SGS type fluid bed. (environmental-expert.com)
  • Pikovskaya O, Serganov AA, Polonskaia A et al (2009) Preparation and crystallization of riboswitch-ligand complexes. (springer.com)
  • Tailor-made auxiliaries that can have molecular recognition with crystallizing molecules have been used to change crystallization behavior [ 7 ]. (hindawi.com)
  • The crystallization kinetics of the additive/APAP mixture on CS substrate was also investigated. (hindawi.com)
  • 4 ], and their results demonstrate the crucial impact of surface morphology on crystallization. (hindawi.com)
  • Nevertheless, crystallizing without confinement, the additive-APAP interaction is more effective at controlling the crystallization of APAP, and the substrates did not have much effect. (hindawi.com)