*  Trans-Cis isomerization of lipophilic dyes probing membrane microviscosity in biological membranes and in live cells
Membrane environment and fluidity can modulate the dynamics and interactions of membrane proteins and can thereby strongly influence the function of cells and organisms in general. In this work, we demonstrate that trans-cis isomerization of lipophilic dyes is a useful parameter to monitor packaging and fluidity of biomembranes. Fluorescence fluctuations, generated by trans-cis isomerization of the thiocarbocyanine dye Merocyanine 540 (MC540), were first analyzed by fluorescence correlation spectroscopy (FCS) in different alcohol solutions. Similar isomerization kinetics of MC540 in lipid vesicles could then also be monitored, and the influence of lipid polarity, membrane curvature, and cholesterol content was investigated. While no influence of membrane curvature and lipid polarity could be observed, a clear decrease in the isomerization rates could be observed with increasing cholesterol contents in the vesicle membranes. Finally, procedures to spatially map photoinduced and thermal ...
*  Positional isomer | definition of positional isomer by Medical dictionary
Looking for online definition of positional isomer in the Medical Dictionary? positional isomer explanation free. What is positional isomer? Meaning of positional isomer medical term. What does positional isomer mean?
*  Nonlinear Optical Properties of Green Fluorescent Protein Chromophore Coupled Diradicals Acta Phys Chim Sin
The geometries, polarizabilities (αs), and first hyperpolarizabilities (βtot) of a series of green fluorescent protein chromophore coupled diradicals and their corresponding optical isomers were investigated using density functional theory (DFT). The results show that the introductions of the electron donor/acceptor significantly enhance the polarizabilities and have a different influence on the first hyperpolarizabilities. For trans isomers, the βtot values of the studied compounds increase with increasing strength of the electron-withdrawing ability of the substituent, whereas the βtot values decrease significantly with increasing strength of the electron-donating ability of the substituent. For cis isomers, the trends in the changes in the βtot values are the opposite of those for trans isomers on introduction of a donor/acceptor. Significantly, photoisomerization can lead to the different βtot values. The βtot values of cis isomers are smaller than those of trans isomers when electron ...
*  IDEALS @ Illinois: Ir-driven Dynamics Of The 3-aminophenol-ammonia Complex
We report on gas-phase experiments investigating the predissociation and possible IR-driven isomerization of the 3-aminophenol-ammonia complex (3-AP-NH$_{3}$). A molecular beam of 3-AP-NH$_{3}$ is vibrationally excited with pulsed IR light, initiating an intramolecular vibrational redistribution and subsequent dissociation. The 3-AP fragment is then probed state-selectively via multiphoton ionization (REMPI) and time-of-flight mass spectrometry. Of particular interest is an IR-driven feature which we associate tentatively with a trans-cis isomerization process. We see clear correlation between the excitation of specific vibrational modes (namely the NH$_{3}$ symmetric and OH stretches) and the presence of this feature, as evidenced by IR-action and IR-depletion spectra. The feature persists atop a broader signal which we assign to the predissociation of the complex and whose cutoff in REMPI-action experiments provides an upper bound on the dissociation energy for 3-AP-NH$_{3 ...
*  Structure Cluster - 1KV0: Cis/trans Isomerization of Non-prolyl Peptide Bond Observed in Crystal Structure of an...
1KV0: Structural mechanism governing cis and trans isomeric states and an intramolecular switch for cis/trans isomerization of a non-proline peptide bond observed in crystal structures of scorpion toxins.
*  Isomerism
explanation of isomerism, isomers, Explanation for Classification of isomerism, Examples for Functional Isomers, positional isomers, chain isomers, explanation for constitutional isomerism, structural isomerism
*  Optical isomerism | Define Optical isomerism at Dictionary.com
Optical isomerism definition, stereoisomerism in which the isomers are identical in molecular weight and most chemical and physical properties but differ in their effect on the rotation of polarized light. See more.
*  Azobenzene: Aspects, Applications and Research
Azobenzene (AZB is characterized by two phenyl rings connected by an azo linkage ( N=N ), that can exist in either the cis or trans conformations. This book provides new research on this chemical compound. Chapter One presents an overview regarding research progress and its reflections in applications of azobenzene-containing derivatives. Chapter Two reviews recent advances in hybrid azobenzene-silica materials. Chapter Three demonstrates the general concepts and potential applications of azobenzene-based liquid crystallines by understanding the relationships of molecular design-structural symmetry-morphological aspect-optical property. Chapter Four focuses on the synthesis, photo- and thermal isomerizations of azobenzenes incorporated in macrocyclic coordination compounds, and discusses the effect of macrocyclic structures on the isomerization of azobenzenes. Chapter Five studies wavelength dependence of polarized UV light induced supramolecular orientation of azobenzene-containing ...
*  EP 0987265 A1 20000322 - Interleukin-5 inhibiting 6-azauracil derivatives
293649200 - EP 0987265 A1 2000-03-22 - Interleukin-5 inhibiting 6-azauracil derivatives - The present invention is concerned with the compounds of formula CHEM the N-oxides, the pharmaceutically acceptable addition salts and the stereochemically isomeric forms thereof, wherein p is 0 to 4; X is O, S, NR 5 or a direct bond; Y is O, S, NR 5 or S(O)2; R 1 independently is C1-6alkyl, halo, polyhaloC1-6alkyl, hydroxy, mercapto, C1-6alkyloxy, C1-6alkylthio, C1-6alkylcarbonyloxy, aryl, cyano, nitro, Het 3 , R 6 , NR 7 R 8 or substituted C1-4alkyl; R 2 is Het 1 , C3-7cycloalkyl or optionally substituted C1-6alkyl and if X is O, S or NR 5 , then R 2 may also represent aminocarbonyl, aminothiocarbonyl, C1-4alkylcarbonyl, C1-4alkylthiocarbonyl, arylcarbonyl, arylthiocarbonyl, Het 1 carbonyl or Het 1 thiocarbonyl; R 3 and R 4 independently are hydrogen, C1-6alkyl or C3-7cycloalkyl; R 3 and R 4 form a C2-6alkanediyl; R 5 is hydrogen or C1-4alkyl; R 6 a sulfonyl or sulfinyl derivative; R 7 and R 8 are
The compounds of the invention, in particular the compounds according to Formula (I), the pharmaceutically acceptable acid or base addition salts thereof, the stereochemically isomeric forms thereof and the N-oxide form thereof and the prodrugs, or any subgroup thereof may be formulated into various pharmaceutical forms for administration purposes. As appropriate compositions there may be cited all compositions usually employed for systemically administering drugs. To prepare the pharmaceutical compositions of this invention, an effective amount of the particular compound, optionally in addition salt form, as the active ingredient is combined in intimate admixture with a pharmaceutically acceptable carrier, which carrier may take a wide variety of forms depending on the form of preparation desired for administration. These pharmaceutical compositions are desirable in unitary dosage form suitable, in particular, for administration orally, rectally, percutaneously, by parenteral injection or by ...
*  Re: What does enzyme mean?
Enzymes are the large group of proteins, which can be defined as biocatalysators of various metabolic reactions. In simple words an enzyme "speeds up" the reaction process. Thus, the reactions which normally would require several hours, weeks, or months can be completed within miliseconds. The enzyme is involved in lowering the energy level required for the reaction to be run. There are specific enzymes for each reaction occuring in metabolism of a living organism. We define six major groups of the enzymes depending on the specificity of the reaction catalysed by them: - Oxidoreductases - participating in red-ox reactions - Transferases - participating in tranferring certain groups from one molecule to another - Hydrolases - participating in hydrolytic cleavage of the bond in the molecule - Lyases - participating in splitting the molecule into smaller products - Isomerases - participating in changing the molecule into its isomeric form - Ligases - participating in merging two or more molecules ...
*  H. P. Lovecraft And His Legacy: Brief Technical Note on "Winged Death"
Two isomeric forms, with the same molecular weight, have been separated from the reaction product. The a-isomer is much more readily soluble in water, alcohol, and chloroform…. This was announced in the very technical journal literature, (E. G. J. Hartley, Chem. Soc. Trans. 1910, 1066 and 1725 ; ibid. 1911, 1549; ibid. 1912, 705; ibid. 1913, 1196 ...
*  Electrochemical control of the switching process of photochromic dimethyldihydropyrene derivatives - Chemical Communications ...
The electrochemical control of the isomerization process of a photo-switchable dimethyldihydropyrene (DHP) derivative has been investigated. Spectro-electrochemical experiments clearly evidence that the substitution of the DHP core by electron-withdrawing entities can be used to control the opening/closing p
*  Definition for geometric isomerism
geometric isomerism definition: A form of isomerism by which, in a single isomer two atoms or teams are on the same side of the jet of a double bond or band, whereas inside various other isomer they have…
*  Solution - Isomerism in Coordination Compounds - Structural Isomerism | shaalaa.com
Solution for concept: Isomerism in Coordination Compounds - Structural Isomerism. For the courses 12th CBSE (Arts), 12th CBSE (Commerce), 12th CBSE (Science), PUC Karnataka Science
*  Patent US4467112 - Process for producing p-n-alkylbenzoic acid - Google Patents
p-n-Alkylbenzoic acids having high purity without containing isomers are important as intermediates for liquid crystals. The p-n-alkylbenzoic acid is produced by reacting a p-formylbenzoic acid or its ester with a ketone having the formula ##STR1## wherein R represents a C1 -C18 n-alkyl or n-alkenyl group in the presence of a basic catalyst to obtain an unsaturated ketone compound having the formula ##STR2## wherein R is defined above and X represents hydrogen atom or a C1 -C6 alkyl group, and then, hydrogenating and reducing the unsaturated ketone compound to obtain the p-n-alkylbenzoic acid having the formula ##STR3##
*  Molecules | Free Full-Text | Coordination Programming of Photofunctional Molecules
Our recent achievements relating to photofunctional molecules are addressed. Section 1 discloses a new concept of photoisomerization. Pyridylpyrimidine-copper complexes undergo a ring inversion that can be modulated by the redox state of the copper center. In combination with an intermolecular photoelectron transfer (PET) initiated by the metal-to-ligand charge transfer (MLCT) transition of the Cu(I) state, we realize photonic regulation of the ring inversion. Section 2 reports on the first examples of heteroleptic bis(dipyrrinato)zinc(II) complexes. Conventional homoleptic bis(dipyrrinato)zinc(II) complexes suffered from low fluorescence quantum yields, whereas the heteroleptic ones feature bright fluorescence even in polar solvents. Section 3 describes our new findings on Pechmann dye, which was first synthesized in 1882. New synthetic procedures for Pechmann dye using dimethyl bis(arylethynyl)fumarate as a starting material gives rise to its new structural isomer. We also demonstrate potentiality of
*  Isomerism | chemistry | Britannica.com
Isomerism: Isomerism, the existence of molecules that have the same numbers of the same kinds of atoms (and hence the same formula) but differ in chemical and physical properties. The roots of the word isomer are Greek-isos plus meros, or
*  CHEM-GUIDE: Definition of structure isomerism
When two or more organic compounds have the same molecular formula but different structural formulae, they exhibit structural isomerism.. There are 5 different kinds of structural isomerism. They are:. ...
*  21662-16-8 - trans,trans-2,4-Dodecadienal, 90+%, remainder mainly trans, cis isomer - L06002 - Alfa Aesar
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*  Bisimines
Figure 2. Structures of the (E,E)-isomers of 3 (R = H, left column) and 4 (R = CH3). Cis before trans isomers and anti and syn alternate. ...
*  cis-trans isomerism - oi
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*  What is Isomerism?
Compounds having the same chemical formula but different physical and chemical properties due to the different structural arrangements are called isomers.
*  Isomers: Definition, Types & Examples - Video & Lesson Transcript | Study.com
Isomers play an important role in the biology of life. Would you like to know how to spot a cis-isomer or a trans-isomer? In this lesson, we'll...