Xem 1-9 trên 9 kết quả Uv absorber
  • The extent to which an organic molecule absorbs electromagnetic radiation in the ultraviolet region (UV light) depends on the structure of the molecule. Generally, molecules that contain one single double bond absorb weakly in the UV region. However, if multiple double bonds are present in a molecule and they are conjugated, the molecule absorbs more strongly and the absorbance is shifted to longer wavelengths. The pH of the mobile-phase effects the ionization of ionogenic solutes and also the analyte UV response.

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  • This study was performed to develop software sensorsto predict the BOD5 of river water and wastewater. The software sensors were based on the multiple-regression analysis using the dissolved organic carbon(DOC) concentration, UV light absorbance at 254nm and synchronous fluorescence spectra. River water samples and wastewater treatment plant (WWTP)effluents were collected at 1-hour interval to evaluatethe feasibility of the software sensors.

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  • Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: The encapsulation effect of UV molecular absorbers into biocompatible lipid nanoparticles

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  • Akcros stabilizer/activators have been formulated to provide controlled, uniform gas evolution for the production of PVC foams utilizing azodicarbonamide as the blowing agent. The ABC series of blowing agent catalysts are primary materials and act as both heat stabilizers and gas generation activators. No secondary stabilizer is normally required. Thus, with the availability of such blowing agent catalysts, the use range of azodicarbonamide is extended to a significant degree.

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  • Anovel photoprotectivemycosporinewas isolated fromthe lichenized ascomyceteCollema cristatum. Biological activity was measured in terms of protection against UV-B induced membrane destruction and pyrimidine dimer formation in cultured human keratinocytes, and prevention of UV-B induced erythema. It was found that the pure isolated compound prevented UV-B induced cell destruction in a dose-dependent manner, that the compound partially pre-vented pyrimidine dimer formation and completely preven-ted UV-B induced erythema when applied to the skin prior to irradiation....

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  • LIF (laser-induced fluorescence) is a very popular CE detector – These have ~0.01 attomole sensitivity for fluorescent molecules (e.g. derivatized proteins). Direct absorbance (UV-Vis) can be used for organics. For inorganics, indirect absorbance methods are used instead, where a absorptive buffer (e.g. chromate) is displaced by analyte ions – Detection limits are in the 50-500 ppb range. Alternative methods involving potentiometric and conductometric detection are also used – Potentiometric detection: a broad-spectrum ISE – Conductometric detection: like IC...

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  • Molecular Targets for UVR-Induced Skin Effects Epidermal DNA, predominantly in keratinocytes and in Langerhans cells (LCs), which are dendritic antigen-presenting cells, absorbs UV-B and undergoes structural changes including the formation of cyclobutane dimers and 6,4photoproducts. These structural changes are potentially mutagenic and can be repaired by mechanisms that result in their recognition and excision and the reestablishment of normal base sequences.

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  • The changes in the far-UV CD signal, intrinsic tryptophan fluorescence and bilirubin absorbance showed that the guanidine hydrochloride (GdnHCl)-induced unfolding of a multidomain protein, human serum albumin (HSA), followed a two-state process. However, using environment sensitive Nile red fluorescence, the unfolding and folding pathways ofHSA were found to followa three-state process andanintermediatewas detectedinthe range0.25–1.5M GdnHCl.

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  • The hydrogenase maturation proteins HypF and HypE catalyze the synthesis of theCNligands of the active site iron of the NiFe-hydrogenases using carbamoylphosphate as a substrate. HypE protein fromEscherichia coliwas purified from a transformant overexpressing thehypEgene from a plasmid. PurifiedHypE in gel filtration experiments behaves predominantly as a monomer. It does not contain statisti-cally significant amounts ofmetals or of cofactors absorbing in the UV and visible light range.

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