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51.
A Reevaluation of the Photolytic Properties of 2‐Hydroxybenzophenone‐Based UV Sunscreens: Are Chemical Sunscreens Inoffensive? 下载免费PDF全文
Dr. Marta T. Ignasiak Prof. Dr. Chantal Houée‐Levin Dr. Gabriel Kciuk Prof. Dr. Bronislaw Marciniak Dr. Tomasz Pedzinski 《Chemphyschem》2015,16(3):628-633
The excited states of a set of popular sunscreen agents (2‐hydroxybenzophenone, oxybenzone, and sulisobenzone) are studied by using femto‐ and nanosecond time‐resolved spectroscopy. Upon excitation, the compounds undergo an ultrafast excited‐state intramolecular proton transfer (ESIPT) reaction as the major energy‐wasting process and the rate constant of this reaction is k=2×1012 s?1. The ESIPT yields a keto conformer that undergoes a fast, picosecond internal conversion decay. However, a photodegradative pathway is a monophotonic H?O bond breakage that subsequently leads to trace yields of phenoxyl radicals. Because potentially harmful phenoxyl radicals are formed upon irradiation of sunscreen agents, care should be taken about their reactivity towards biologically relevant compounds. 相似文献
52.
Ewa Rozycka‐Sokolowska Andrzej Borowski Bernard Marciniak 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(6):o209-o211
The structure of the title compound, C6H6OS, exhibits a flip‐type disorder of the thiophene ring [occupancy ratio = 0.848 (3):0.152 (3)], which is typical for many thiophene derivatives. The puckered thiophene ring is essentially coplanar with the plane formed by the non‐H atoms of the acetyl substituent, similar to its simple analogues, i.e. 3‐acetyl‐2‐carboxythiophene, 4‐acetyl‐3‐carboxythiophene and 3,5‐diacetyl‐2‐ethylamino‐4‐methylthiophene. In the crystal structure, molecules are connected by C—H...π hydrogen bonds, forming a sheet parallel to the (001) plane. Moreover, an inspection of the crystal lattice reveals that there are short S...O contacts connecting the molecules of adjacent sheets. Comparison of the title crystal structure with its simple 3‐methoxythiophene analogue shows a close similarity in the herringbone arrangement of molecules and in the presence of C—H...π interactions and S...O contacts. 相似文献
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The ability to effectively detect disease-related DNA biomarkers and drug delivery nanoparticles directly in blood is a major challenge for viable diagnostics and therapy monitoring. A DEP method has been developed which allows the rapid isolation, concentration and detection of DNA and nanoparticles directly from human and rat whole blood. Using a microarray device operating at 20 V peak-to-peak and 10 kHz, a wide range of high molecular weight (HMW)-DNA and nanoparticles were concentrated into high-field regions by positive DEP, while the blood cells were concentrated into the low-field regions by negative DEP. A simple fluidic wash removes the blood cells while the DNA and nanoparticles remain concentrated in the DEP high-field regions where they can be detected by fluorescence. HMW-DNA could be detected at 260 ng/mL, which is a detection level suitable for analysis of disease-related cell-free circulating DNA biomarkers. Fluorescent 40 nm nanoparticles could be detected at 9.5 × 10(9) particles/mL, which is a level suitable for monitoring drug delivery nanoparticles. The ability to rapidly isolate and detect DNA biomarkers and nanoparticles from undiluted whole blood will benefit many diagnostic applications by significantly reducing sample preparation time and complexity. 相似文献
55.
In this paper, we discuss the conditions under which the coupled KdV and coupled Harry Dym hierarchies possess inverse (negative) parts. We further investigate the structure of nonlocal parts of tensor invariants of these hierarchies, in particular, the nonlocal terms of vector fields, conserved one‐forms, recursion operators, Poisson and symplectic operators. We show that the invertible coupled KdV hierarchies possess Poisson structures that are at most weakly nonlocal while coupled Harry Dym hierarchies have Poisson structures with nonlocalities of the third order. 相似文献
56.
Ewa Rozycka‐Sokolowska Bernard Marciniak Volodymyr Pavlyuk Euzebiusz Dziwinski 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(1):o45-o46
Molecules of the title compound [systematic name: 2,4′‐(propane‐2,2‐diyl)diphenol], C15H16O2, are linked through intermolecular O—H·O hydrogen bonds into infinite zigzag chains. The molecular structure is compared with that of the related compound 4,4′‐isopropylidenediphenol. 相似文献
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B. Marciniak 《Crystal Research and Technology》1991,26(7):855-862
The present work summarizes results concerning growth of anthracene, pyrene, p-terphenyl, carbazole, and phenanthrene single crystals by Bridgman method. The temperature conditions and rate of crystal growth as well as seeding conditions have been determined and discussed in the aspect of purity grade of considered materials. 相似文献
59.
Karol Bukowski Beata Marciniak Mateusz Kciuk Mariusz Mojzych Renata Kontek 《Molecules (Basel, Switzerland)》2022,27(12)
In this paper, we present for the first time the evaluation of cytotoxicity and genotoxicity of de novo synthesized pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides MM129, MM130, and MM131 in human tumor cell lines: HeLa, HCT 116, PC-3, and BxPC-3. Cytotoxic and genotoxic properties of the tested compounds were estimated using the MTT assay, comet assay (alkaline and neutral version), and γ-H2AX immuno-staining. Examined sulfonamides exhibited strong anticancer properties towards tested cells in a very low concentration range (IC50 = 0.17–1.15 μM) after 72 h exposure time. The results of the alkaline and neutral version of the comet assay following 24 h incubation of the cells with tested compounds demonstrated the capability of heterocycles to induce significant DNA damage in exposed cells. HCT 116 cells were the most sensitive to the genotoxic activity of novel tricyclic pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides in the neutral version of the comet assay. Immunocytochemical detection of γ-H2AX showed an increase in DNA DSBs level in the HCT 116 cell line, after 24 h incubation with all tested compounds, confirming the results obtained in the neutral comet assay. Among all investigated compounds, MM131 showed the strongest cytotoxic and genotoxic activity toward all tested cell types. In conclusion, our results suggest that MM129, MM130, and MM131 exhibit high cytotoxic and genotoxic potential in vitro, especially towards the colorectal cancer cell line HCT 116. However, further investigations and analyses are required for their future implementation in the field of medicine. 相似文献
60.