This review exposes the current poor understanding of the internal segmental chain dynamics of dendrimers in solution probed by monitoring the process of excimer formation between pyrene labels covalently attached to the chain ends of dendrimers. The review begins by covering the bases of fluorescence and the kinetics of pyrene excimer formation before describing a procedure based on the Model Free (MF) analysis that is used to analyze quantitatively the fluorescence decays acquired for dendrimers, the ends of which have been fully and covalently labeled with pyrene. Comparison of the various trends obtained by different research groups describing the efficiency of pyrene excimer formation with the generation number of dendrimers illustrates the lack of consensus between the few studies devoted to the topic. One possible reason for this disagreement might reside in the presence of minute amounts of unattached pyrene labels which act as potent fluorescent impurities and affect the analysis of the
Pyrene derivatives can be carcinogenic, teratogenic and mutagenic, thus having the potential to cause malignant diseases. In this work, the interactions of two selected pyrene derivatives (1-OHP and 1-PBO) and human tumor-related DNA (p53 DNA and C-myc DNA) are investigated by spectroscopic and non-native polyacrylamide gel electrophoresis (PAGE) methods. Using fluorescence spectrometry and circular dichroism (CD), DNA interactions of pyrene derivatives are confirmed to occur mainly via the groove binding mode supported by the intercalation into the base pairs of DNA. There is an obvious binding order of pyrene derivatives to the targeted DNA, 1-OHP | 1-PBO. The binding constants of 1-OHP are 1.16 × 106 L×mol−1 and 4.04 × 105 L×mol−1 for p53 DNA and C-myc DNA, respectively, while that of 1-PBO are only 2.04 × 103 L×mol−1 and 1.39 × 103 L×mol−1 for p53 DNA and C-myc DNA, respectively. Besides, the binding of pyrene derivatives to p53 DNA is stronger than that for C-myc DNA. CD and PAGE
1-Nitro[U-4,5,9,10-14C]pyrene was synthesized and administered to male F344 rats by intragastric gavage at a dose of 100 mg/kg of body weight. During the first 48 hr, 41% of the dose was eliminated in the feces, and 16% was eliminated in the urine. The corresponding figures after 120 hr were 51 and 19%. In rats with bile cannulae, 37% of the dose was excreted in the bile after 72 hr, and 6% was excreted in the urine. Fecal metabolites included 1-aminopyrene (isolated amount, 11.7% of the dose), 1-amino-6-hydroxypyrene and 1-amino-8-hydroxypyrene (4.6%), and unchanged 1-nitropyrene (6.6%). 1-Aminopyrene and the 1-aminohydroxypyrenes were identified as their acetyl-derivatives by comparison of their chromatographic retention times, mass spectra, and UV spectra to those of synthetic standards. Biliary metabolites included 1-aminopyrene, 1-amino-6-hydroxypyrene, 1-amino-8-hydroxypyrene, 1-nitro-6(8)-hydroxypyrene, and 1-nitro-3-hydroxypyrene, as well as their glucuronide and sulfate conjugates. The ...
Excimers play a key role in a variety of excited-state processes, such as exciton trapping, fluorescence quenching, and singlet-fission. The dynamics of benzene excimer formation in the first 2 ps after S1 excitation from the parallel-displaced geometry of the benzene dimer is reported here. It was simulated Photodissociation and reaction dynamics 2018 PCCP HOT Articles
A new N-thiophosphorylated thiourea (1-pyrene)NHC(S)NHP(S)(OiPr)2 (HL) has been synthesized. The molecular structure of HL was elucidated by X-ray diffraction revealing a linear intramolecular hydrogen bond. Additionally, its crystal structure is stabilized by two intermolecular hydrogen bonds, which in turn
The rate parameters of solvent-solute energy transfer and of oxygen-solvent quenching have been determined for solutions of 2, 5-diphenyloxazole in benzene, toluene, p-xylene and mesitylene. The role of excited molecules and excimers in transfer to the solute molecules is considered in terms of the Voltz relations, which include the Förster critical transfer distance, the molecular diffusion coefficients, and the solvent excitation migration coefficient. It is proposed that the migration is due to excimer formation and dissociation, and that the energy transfer occurs by a diffusion/migration-controlled collisional process. Dilution of the solvent decreases the migration, but increases the transfer distance, so that the transfer efficiency remains practically constant. The excimer formation and dissociation rate parameters in the pure alkyl benzenes are evaluated. ...
TY - JOUR. T1 - A dipyrenyl calixazacrown chemosensor for Mg2+ AU - Hamdi, Abdelwaheb. AU - Kim, Sang Hoon. AU - Abidi, Rym. AU - Thuéry, Pierre. AU - Kim, Jong Seung. AU - Vicens, Jacques. PY - 2009/4/4. Y1 - 2009/4/4. N2 - A new fluorogenic calix[4]tetraaza-crown-6 (4) bearing two pyrene amide groups has been prepared. It was shown to be selective for Mg2+. When Mg2+ is bound to 4, the pyrene monomer emission increased while the excimer emission declined in a ratiometric manner. It is shown by 1H NMR that this ratiometric change is due to the conformational changes of the pyrenes during the chelation of Mg2+ by the amide functions to form a 1:1 complex.. AB - A new fluorogenic calix[4]tetraaza-crown-6 (4) bearing two pyrene amide groups has been prepared. It was shown to be selective for Mg2+. When Mg2+ is bound to 4, the pyrene monomer emission increased while the excimer emission declined in a ratiometric manner. It is shown by 1H NMR that this ratiometric change is due to the ...
Precautionary Statements: P260-P271-P304+P340-P312-P314-P501c Do not breathe dust/fume/gas/mist/vapours/spray. Use only outdoors or in a well-ventilated area. IF INHALED: Remove to fresh air and keep at rest in a position comfortable for breathing. Call a POISON CENTER or doctor/physician if you feel unwell. Get medical advice/attention if you feel unwell. Dispose of contents/ container to an approved waste disposal plant ...
The report generally describes cyclopenta[c,d]pyrene, examines its uses, production methods, patents. Cyclopenta[c,d]pyrene market situation is overviewed;
Mitch Winnik received a B.A. degree from Yale University in 1965. He obtained his Ph.D. degree in the area of organic chemistry at Columbia University in 1969, working under the direction of Prof. Ronald Breslow, and then spent a year as a postdoctoral fellow in the laboratory of Prof. George Hammond at Caltech studying organic photochemistry. He joined the faculty at the University of Toronto in 1970, and received tenure as an organic chemist. On his first sabbatical, in Bordeaux France, he realized that he was bored with what he had been doing and decided to switch his attention to longer molecules. Upon his return to Toronto, he and his coworkers prepared a series of polymers with a pyrene group at both ends. The pyrene groups emit a blue fluorescence if the pyrenes are far apart, but if an excited pyrene during its lifetime can find a second pyrene, they form a sandwich structure which emits a green "excimer" fluorescence. In dilute solution, the rate of excimer formation from the ...
The rates of interactions of polycyclic aromatic hydrocarbons (PAHs) with biological cells studied with fluorescence appear to be different for cells from different origins. The monomer emission of benzo[,i,a,/i,]pyrene (BaP) is enhanced as in liposomes, but more significantly in normal liver cells than in liver cancer cells or kidney cells, and that enhancement is proportional to the amount of cells added. When PAHs are allowed to interact with cells for a certain period of time, metabolism appears to occur. The excimer emission is seen to dissipate continuously as reactions proceed, whereas the monomer emission increases, passes through a maximum, then starts to decrease when excimer emission becomes exhausted. The time plot of the BaP excimer emission in semilogarithmic coordinates indicates that the decrease or the mass transfer of microcrystalline BaP to the cell membrane is a first-order process. Metabolism has been investigated by monitoring the monomer emission. Liver cells have higher ...
The fluorescence lifetimes of a number of aromatic hydrocarbons are shortened by 15-40% when the matrix is compressed by 30 kbar pressure. The causes of environmentally-induced lifetime shortening may be further illuminated by a detailed study of one solute under a variety of conditions. The document reports on such a study of pyrene and in addition, compares the pressure-enhanced electronic relaxation for the monomeric and excimeric forms of pyrene. The work established the magnitude of environmental influences on the singlet lifetime of pyrene and demonstrated a remarkable insensitivity of the emitting species to the nature of the microscopic surroundings, be it monomer or excimer.(*POLYCYCLIC COMPOUNDS
Pyrene is a fluorescent polycyclic aromatic hydrocarbon. It is useful as a proximity sensor - when two pyrene residues are spaced close to each other, they exhibit easily detectable excimer fluorescence.
4-Nitropyrene was tested for carcinogenicity in newborn rats by subcutaneous injection, producing an increase in the incidence of mammary tumours. It was also tested by intraperitoneal injection in newborn mice, producing an increase in the incidence of liver-cell tumours in males and of lung tumours in animals of each sex. A study by intraperitoneal injection was inadequately reported ...
4FBT: Structural mechanism of replication stalling on a bulky amino-polycyclic aromatic hydrocarbon DNA adduct by a y family DNA polymerase.
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102859-52-9 - SQAFYTHBQZQFLZ-UHFFFAOYSA-N - Cyclopenta(cd)pyrene, 4-nitro- - Similar structures search, synonyms, formulas, resource links, and other chemical information.
Phenylethynylpyrene (PEP) is a pyrene derivative with red-shifted absorption and emission spectra. Fits blue channel of qPCR instruments, can be used for multiplex experiments.
Affiliation:香川医科大学,医学部,副学長, Research Field:病院管理学, Keywords:1-nitropyrene,大気中粒子状物質,エアロゾル,変異原性,大気汚染,粒子,benzo(a)pyrene,DNA付加体,ダイオキシン,1、6-dinitropyrene, # of Research Projects:6, # of Research Products:0
Product Name: 1-HydroxypyreneFormula: C16H10OWeight: 218.25SMILES: OC1C2C3=C4C(C=CC=C4C=CC3=CC=1)=CC=2CAS NO: 917497-70-2 Product: SC144 (hydrochloride)
The Koggala lagoon is a coastal wetland affected by a major oil spill and other anthropogenic pollution sources. In this study, gill and liver histological alterations and polycyclic aromatic hydrocarbon (PAH) exposure indicative bile fluorescence patterns of the fish species inhabiting the lagoon were examined in order to explore the potential biological impacts. Fixed wavelength fluorescence patterns in the bile of Mugil cephalus, Lutjanus russellii and Etroplus suratensis showed bioavailability of naphthalene type-, phenanthrene type-, pyrene type- and benzo(a)pyrene type- metabolites indicating recent exposure of the fishes to petrogenic and pyrogenic PAHs. Histological analysis revealed the occurrence of prominent gill and liver lesions, especially in the tissues of M. cephalus and L. russellii. Of the fish species examined, which included 43 individual fishes, the liver tissues of M. cephalus (two fish) and L. russellii (one fish) displayed foci of hepatocellular alterations with nodular ...
Characterization of a pyrene-degrading Mycobacterium sp. strain CH-2.: Mycobacterium sp strain CH-2 was isolated from a manufactured gas plant contaminated with
A new approach is presented to obtain fluorescent sensors for pH windows that work in water and under biomimetic conditions. A single molecule that features all-covalently linked components is used, thus making it capable of working as a fluorescent sensor with an OFF/ON/OFF response to pH value. The components are a tertiary amine, a pyridine, and a fluorophore (pyrene). The forms with both protonated bases or both neutral bases quench the pyrene fluorescence, whereas the form with the neutral pyridine and protonated amine groups is fluorescent. The molecular sensor is also equipped with a long alkyl chain to make it highly hydrophobic in all its protonated and unprotonated forms, that is, either when neutral or charged. Accordingly, it can be confined at any pH value either in traditional (i.e., low-molecular-weight) nonionic surfactant micelles or inside polymeric, biocompatible micellar containers. Relevant for future applications in vivo, thanks to its strong hydrophobicity, no leakage of ...
We made two important contributions to this field. First, we developed a method based upon pyrene fluorescence, to determine the critical aggregation concentration for polymers in water. [see Macromolecules, 24, 1033-1040 (1991)] This is our most cited paper because it shows how one can distinguish between the true CAC and a partition equilibrium that might resemble the CAC. The second contribution is more subtle. We showed, for the case linear PEO with C16H33- end groups where the rheological behavior is remarkably simple, that flower-like micelles exist at low concentration, and undergo a transition to bridged micelles as higher concentrations. [see Macromolecules, 25, 7024-7030 (1992)] More important, we showed that both shear and extensional flow induced a bridge-to-loop transition of the PEO, leading to smaller structures, and lower solution viscosity, and throughout this transition, the mean size of the individual micelles (20 C16 chains per micelle) was unaffected. [see Langmuir, 9, ...
PMID 16864595] The influence of genetic polymorphisms in Ahr, CYP1A1, CYP1A2, CYP1B1, GST M1, GST T1 and UGT1A1 on urine 1-hydroxypyrene glucuronide concentrations in healthy subjects from Rio Grande do Sul, Brazil. ...
Cells derived from mixed Syrian hamster embryo cultures were treated with pyrene (control) or with benzo[a]pyrene. Transformed clones were obtained only with the carcinogen. Some of the transformed clones were responsible for cell lines that produced tumors when injected into hamsters. These observations provide evidence that chemical-induced oncogenesis can be studied by an in vitro model. ...
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A new heterometallic diruthenium(III)-magnesium(II) complex functionalized with four pyrenecarboxylate fluorophores ,b,1,/b, has been synthesized and structurally characterized. Fluorescence from the pyrene moieties in ,b,1,/b, was nearly completely quenched in CH,sub,2,/sub,Cl,sub,2,/sub, (,98%), but turn-on fluorescence was successfully observed after regioselective substitution of the carboxylates bridging the heterometallic Ru(III)···Mg(II) sites.. ...
Under EPAs Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005a), benzo[a]pyrene is "carcinogenic to humans" based on strong and consistent evidence in animals and humans ...
Backer, J M. and Weinstein, I B., "Interaction of benzo(a)pyrene and its dihydrodiol-epoxide derivative with nuclear and mitochondrial dna in c3h10t1/2 cell cultures." (1982). Subject Strain Bibliography 1982. 181 ...
benzo[a]pyrene | C20H12 | CID 2336 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more.
Rigdon, R H.; Benge, M C.; Kirchoff, H; Mack, J; and Neal, J, "Leukemia in mice fed benzo(a)pyrene, a clinical, pathologic and hematologic study." (1969). Subject Strain Bibliography 1969. 1799 ...
Page contains details about [email protected](1,6-bis(4-(((pyridin-2-yl)methylidene)amino)phenyl)pyrene)6(NTf2)8 . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
1,2-Epoxy-1,2,3,4-tetrahydrodibenzo(a,h)pyrene | C24H16O | CID 54292 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more.
3-Methoxybenzo[a]pyrene/ACM63059687 can be provided in Alfa Chemistry. We are dedicated to provide our customers the best products and services.
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RE: New COKE formula.. We were discussing this the other evening, and someone came up with an interesting thoery.. Seems that COKE signed a contract in the early 1900s with their original distributors to sell their original formula for a fixed price (a price cap). Since then inflation has really hit hard, and COKE has been actively buying distributors for the last few years to get rid of the contracts, and then reselling the distributorships at terms more lucrative to COKE.. However, if they change the formula, then the agreement no longer applies. COKE can afford to lose market share, and still make larger profits. The only ones who lose are the consumers and the distributors.. Some of this is verifiable, some is pure conjecture. Treat this as net.rumor.. Jay ...
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A device for measuring a shape of a wall portion of an oven, such as a coke oven, the device comprising: - a box (20) having a main part (38) defining at least one opening (44) and a closing system (40) movable with respect to the main p ...
NICE has taken the fizz out of its good advice to parents to not run to us about juniors squits by vetoing flat coke or juice as a helpful remedy. Based on what evidence, asks Copperfield.
pictorialization genealogical unpaled arriswise subinfeudate undercrust preconfiguration fanlike autolaryngoscope Kalmarian textarian Lycian preambition preintercourse coke Hazara semisupination Anomodontia conglobately [email protected] ...
Twelve workers from a coke plant in The Netherlands participated in an intensive skin monitoring programme combined with personal air sampling and biological monitoring during five consecutive eight hour workshifts. The purpose of the study was to make a quantitative assessment of both the dermal and respiratory intake of polycyclic aromatic hydrocarbons (PAHs). Pyrene was used as a marker compound for both dermal and respiratory exposure to PAHs. The biological measure for the internal exposure to PAHs was urinary 1-OH-pyrene concentration. Measurements on exposure pads at six skin sites showed that mean total skin contamination of the 12 workers ranged between 21 and 166 micrograms pyrene a day. The dermal uptake of pyrene ranged between 4 and 34 micrograms/day, which was about 20% of the pyrene contamination on skin. The mean concentration of total pyrene in the breathing zone air of the 12 coke oven workers ranged from 0.1 to 5.4 micrograms/m3. The mean respiratory uptake of pyrene varied ...
Observations have been made of the concentration dependence of the fluorescence spectra of solutions of 1:2-benzanthracene and fifteen of its hydrocarbon derivatives. All of the compounds, except the 9,10-dim ethyl derivative, exhibit dim er emission at higher concentrations. The lower excited states, 1Lb and 1La, satisfy Försters conditions for fluorescent dim er formation. The factors determining the relative quantum yield of excimer fluorescence are discussed. The different types of crystal fluorescence spectra shown by the compounds are explained in terms of excimer formation in the crystal lattice. ...
An enzyme immunoassay for the detection of benzo[a]pyrene covalently conjugated to macromolecules has been developed. The monoclonal antibody, raised through in vitro immunization reacted with benzo[a]pyrene metabolites bound to DNA, RNA and proteins. The lower detection limit for the assay was 1 pmol for benzo[a]pyrene bound to DNA or RNA, and 5 pmol when bound to protein.
Evaluation of Accelerated Solvent Extraction of deuterated benzo(a)pyrene and dibenzo(a,i)pyrene from Diesel Standard Reference Material 2975 ...
N-(1-L-Phenylalanine)-4-(1-pyrene)butyramide 199612-75-4 Precursor and Downstream products, N-(1-L-Phenylalanine)-4-(1-pyrene)butyramide Precursor products, N-(1-L-Phenylalanine)-4-(1-pyrene)butyramide Downstream products ect.
Polycyclic aromatic hydrocarbons (PAHs), benzene and toluene (BT) are ubiquitous toxic pollutants in the environment. Children are sensitive and susceptible to exposure to these contaminants. To investigate the potential oxidative DNA damage from the co-exposure of PAHs and BT in children, 87 children (aged 3-6) from a kindergarten in Guangzhou, China, were recruited. Ten urinary PAHs and four BT ...
Polycyclic aromatic hydrocarbons (PAHs) are present in both gaseous and particulate phases. These compounds are considered to be atmospheric contaminants and are human carcinogens. Many studies have monitored atmospheric particulate and gaseous phase
Some biotic and abiotic aspects of the environmental chemistry of PAHs (polycyclic aromatic hydrocarbons) and PCDD/Fs (polycychlorinated dibenzodioxins and dibenzofurans) ...
Dynamic changes of glycolipid domains within the plasma membranes of cultured rat cerebellar granule cells have been investigated. For this purpose, a pyrene-labelled derivative of G(M1) ganglioside has been incorporated in the cell plasma membrane, and the rate of excimer formation, directly related to the formation of domains, has been studied by a fluorescence imaging technique (excimer-formation imaging). Fluorescence imaging showed that upon addition of 100 μM glutamate, indirectly inducing the activation of protein kinase C (PKC), glycolipid concentration within domains increases in cell bodies. Comparable effects were exerted by the addition of PMA, directly inducing the activation of PKC. On the contrary, the phorbol ester was not effective in the presence of the specific PKC inhibitor, bisindolylmaleimide. These results suggest that glycolipid-enriched domains are dynamic supramolecular structures affected by membrane-associated events, such as PKC activation. Dynamic changes of ...