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UV Absorption Spectra (uv + absorption_spectrum)
Selected AbstractsAn in vitro evaluation of various Rosa damascena flower extracts as a natural antisolar agentINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 6 2003H. Tabrizi Synopsis The aim of this work was to evaluate ultraviolet (UV) absorption ability of various extracts of Rosa damascena flowers as an antisolar agent. Extracts were prepared using the following solvent mixtures: water:ethanol (50 : 50), ethyl acetate:ethanol (80 : 20) and ether. The hydroalcoholic and ethyl acetate:ethanol extracts were prepared by maceration, and ether extract was prepared by soxhletion. Preliminary studies on the extracts prepared confirmed the presence of flavonoids as the major components of all extracts. Next, the UV absorption spectra (in the range of 200,400 nm) of all extracts were obtained. Results show that all three extracts can effectively absorb UV radiation in the range of 200,400 nm. However, the range giving maximum absorption for the hydroalcoholic, ethyl acetate:ethanol and ether extracts were 200,320, 250,360 and 230,370 nm, respectively. In the next stage, extracts prepared were incorporated into an oil in water cream base (prepared based on preliminary studies), at two concentrations of 5 and 8%. The sun protection factor (SPF) of these creams were determined. Based on the findings, the hydroalcoholic extract seems to give the highest SPF among the three extracts evaluated, when incorporated to the cream base. On the other hand, by performing a few physicochemical tests on the prepared creams, cream containing 5% ether extract showed the most desirable appearance and stability among the creams investigated. The UV absorption ability of these extracts is suggested to be because of the presence of flavonoid compounds within the extracts. However, it should be noted that in order to obtain an effective suncare product with high SPF values, these extracts could be used along with other synthetic antisolar agents. Résumé Le but de ce travail était d'évaluer la capacité d'absorption des Ultraviolets (UV) de différents extraits de fleurs de Rosa damascena en tant qu'agents de protection solaire. Les extraits ont été préparés par utilization des mélanges de solvants suivants: Eau:ethanol (50 : 50), Acetate d'éthyle:ethanol (80 : 20) et l'Ether. Les extraits hydro-alcoolique et d'acétate d'ethyle:ethanol ont été réalisés par macération tandis que l'extrait d'éther était obtenu par l'utilization d'un soxhlet. Les études préliminaires des extraits ainsi préparés confirmaient la présence de flavonoïdes en tant que constituants majeurs de tous les extraits. Les spectres d'absorption UV (échelle 200,400 nm) furent ensuite obtenus. Les résultats montrent que tous les extarits peuvent absorber fortement les radiations UV dans l'échelle de 200 à 400 nm. Cependant, les domaines donnant le maximum d'absorption pour les extraits hydroalcoolique, acétate d'éthyle:ethanol et ether étaient respectivement de 200,320, 250,360 et 230,370 nm. Dans une étape ultérieure, les extraits ont été incorporés dans une base type crème huile dans l'eau (préparée selon des études préliminaires) aux deux concentrations de 5 et 8%. Les facteurs de protection solaire (SPF) de ces crèmes étaient ensuite déterminés. Les résultats ont montré que l'extrait hydroalcoolique semblait, parmi les trois, conduire au plus fort SPF, quand incorporé dans une base type crème. De plus, en conduisant quelques tests physioco chimiques sur les crèmes préparées, la crème contenant 5% de l'extrait par éther, comparé aux autres crèmes, offrait l'aspect le plus désirable et le plus stable. Il est suggéré que la capacité d'absorption UV de ces extraits est due à la présence des composés de type flavonoïdes en leur sein. On doit noter, cependant, qu'afin d'obtenir un produit solaire efficace à haut SPF, ces extraits pourraient être adjoints à d'autres filtres solaires synthétiques. [source] Polymerizable benzophenone derivatives for labeling vinyl acetate-butylacrylate latex particlesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2002Jung Kwon Oh Abstract We describe the synthesis and characterization of three new polymerizable benzophenone derivatives [2-acryloxy-5-methyl benzophenone (8), 4,-dimethylamino-2-acryloxy-5-methyl benzophenone (9), and 4,-dimethylamino-2-(,-acryloxyethyl)oxy-5-methyl benzophenone (10)]. We show that these monomers can successfully be incorporated into vinyl acetate (VAc) copolymer latex particles. These particles were prepared by semicontinuous emulsion polymerization and mini-emulsion polymerization of VAc with butylacrylate (BA) for VAc/BA = 4/1 by weight. The two monomers 9 and 10 bearing the 4,-dimethylamino group satisfy the important spectroscopic criteria required of a dye to serve as an acceptor chromophore for nonradiative energy transfer from phenanthrene (Phe) as the donor. Their UV absorption spectra suggest significant overlap with the emission spectrum of Phe, which can be incorporated into P(VAc- co -BA) latex through copolymerization with 9-acryloxymethyl Phe (2). In addition, these chromophores provide a window in their absorption spectra for excitation of the Phe chromophore at 300 nm. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3001,3011, 2002 [source] Synthesis of CdS Nanoparticles Dispersed Within Poly(urethane acrylate- co -styrene) Films Using an Amphiphilic Urethane Acrylate NonionomerMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 11 2006Ju-Young Kim Abstract Summary: CdS nanoparticles dispersed within poly(urethane acrylate- co -styrene) (PUCS) films were prepared using amphiphilic urethane acrylate nonionomer (UAN) precursor chains, which had a poly(propylene oxide)-based hydrophobic segment and a hydrophilic poly(ethylene oxide) segment. CdS nanoparticles were first prepared and dispersed in UAN/styrene mixtures, and then these nano-colloid solutions could be directly converted to CdS/PUCS nanocomposite films via radical bulk polymerization process. Formation of CdS nanoparticles was confirmed by UV absorption spectra, PL emission spectra and TEM images. The size of the CdS nanoparticles was varied from 10.2 to 14.5 nm, in correlation with the increase of amount of cadmium salt in the preparation composition, which was also confirmed by a red shift in the UV and PL emission spectra. In the course of the formation of the CdS nanoparticles within the UAN/styrene mixtures, the PEO segments of UAN are microphase-separated from the hydrophobic segments of UAN and styrene to make a complex with the cadmium cations and stabilize the CdS nanoparticles. This was also confirmed by TEM images and DMA measurements. TEM micrograph of the polyurethane acrylate films containing CdS nanoparticles, prepared using a weight fraction of cadmium acetate of 0.125 wt.-%. [source] Large scale depletion of the high-abundance proteins and analysis of middle- and low-abundance proteins in human liver proteome by multidimensional liquid chromatographyPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 5 2008Mingxia Gao Abstract An unbiased method for large-scale depletion of high-abundance proteins and identification of middle- or low-abundance proteins by multidimensional LC (MDLC) was demonstrated in this paper. At the protein level, the MDLC system, coupling the first dimensional strong cation exchange (SCX) chromatography with the second dimensional RP-HPLC, instead of immunoaffinity technology, was used to deplete high-abundance proteins. Sixty-two fractions from SCX were separated further by RPLC. UV absorption spectra were observed to differentiate high-abundance proteins from middle- or low-abundance proteins. After the depletion of high-abundance proteins, middle- or low-abundance proteins were enriched, digested, and separated by online 2D-micro-SCX/cRPLC. The eluted peptides were deposited on the MALDI target and detected by MALDI-TOF/TOF MS. This depletion strategy was applied to the proteome of the normal human liver (NHL) provided by the China Human Liver Proteome Project (CHLPP). In total, 58 high-abundance proteins were depleted in one experiment. The strategy increases greatly the number of identified proteins and around 1213 proteins were identified, which was about 2.7 times as that of the nondepletion method. [source] Synthesis, Crystal Structure and Photophysical Properties of a Novel Molecule Containing a Triarylamine and an Oxadiazole UnitsCHINESE JOURNAL OF CHEMISTRY, Issue 10 2002Hai-Tao Yu Abstract 2-{3-[2-(4- N, N -Di- p -tolylaminophenyl)ethenyl]phenyl}-5-(4-bromophenyl)-1,3,4-oxadiazole (1) containing triarylamine and 2,5-diaryi-1,3,4-oxadiazole units was prepared by Homer Witting reactions. The structure of the compound was confirmed by 1H NMR, IR, MS and elemental analyses. The crystal structure of 1 was determined by X-ray diffraction analysis. UV absorption spectra and photoluminescent spectra were measured. [source] Preparation and fluorescence properties of poly(o -methyl-acrylamideyl-benzoic acid)-ZnS compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2010Qing-Feng Xu Abstract Poly(o -methyl-acrylamideyl-benzoic acid)-ZnS (P(o -MAABA)-ZnS) nanocomposites have been prepared and characterized. The resultant P(o -MAABA)-ZnS nanocomposites in solution show two emissions in the purple-light area (370 nm) and in the blue-light area (425 nm), which are assigned to the polymer and ZnS nanoparticles, respectively. The coordination between the polymer and Zn2+ and the surface chemical composition has been studied by Infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The particle size of ZnS nanoparticles was homogeneous and the average size was 3.8 nm, which were characterized by UV absorption spectrum and X-ray Diffraction. The P(o -MAABA)-ZnS composites displays good film formability and the films also show two emissions in 370 and 425 nm. After doped with Tb3+, there was effective energy transfer from ZnS nanoparticles to Tb3+. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Synthesis of Reactive Polymeric Dyes as Textile AuxiliariesMACROMOLECULAR MATERIALS & ENGINEERING, Issue 9 2003Angelina Altomare Abstract New polymeric materials containing amino-substituted azobenzene chromophores and reactive functional groups and characterized by some hydrophilicity were prepared with the aim of investigating alternative textile dyeing routes. The indicated materials were obtained either by copolymerization of suitable monomers or by modification of preformed polymers. In both cases commercial 4-amino-2,,3-dimethylazobenzene (FG) was used as chromogenic compound. According to the first synthetic strategy, the methacrylamido derivative of FG was copolymerized by free radical initiation with different monomers, such as methyl methacrylate, glycidyl methacrylate, N - tert -butylacrylamide, methacrylic acid, N -vinyl-2-pyrrolidinone, and vinyl acetate. Reaction of FG with preformed polymers containing epoxy groups generally afforded crosslinked materials. On the other hand, low FG loading extents were recorded by amidation of polymers containing carboxylic groups. Indeed, almost quantitative conversions were obtained only in the reaction of FG with anhydride containing polymers. The chemical structure, molecular weight properties, and the physical-chemical characteristics of all synthesized polymeric dyes were thoroughly investigated. Some very preliminary dyeing tests of different cloth types with the prepared polymeric dyes were also performed. UV absorption spectrum of poly(FGMAA) and poly(FGMAA- co -MMA) in chloroform at 25,°C (FGMAA,=,4-methacrylamido-2,,3-dimethylazobenzene). [source] Synthesis and photocuring of cinnamoyl trehalose estersPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2007Naozumi Teramoto Abstract A trehalose cinnamoyl ester (TC) was synthesized from trehalose and cinnamoyl chloride in dimethylformamide (DMF) in the presence of triethylamine and 4-(N,N -dimethylamino)pyridine. The product was characterized by 1H NMR spectroscopy to reveal that the reaction proceeded. Two different types of TCs were synthesized by changing the feed ratio of cinnamoyl chloride to trehalose. When the feed ratio of cinnamoyl chloride to trehalose was 8 (TC8), the degree of substitution (DS) was 8.0, while it was 4.2 when the feed ratio was 4 (TC4). Photocuring was confirmed by observing changes in UV absorption spectrum and FT Infrared (IR) spectrum. After 5,min of UV irradiation, solubility in chloroform significantly decreased. A transparent thin coating film of TC was easily prepared by casting from a chloroform solution on a Petri dish and UV irradiation was carried out over a simple photomask. After TC within the non-irradiated region was removed by flash soaking with chloroform, the shape of the photomask appeared. A scanning electron microscope (SEM) measurement revealed that the surface of the photocured coating film was smooth and that the edge of the photocured TC had a characteristic feature. Biodegradation of the photocured TC and non-irradiated TC was examined by the biochemical oxygen demand (BOD) method using activated sludge. Copyright © 2007 John Wiley & Sons, Ltd. [source] Development of the second-order derivative UV spectrophotometric method for direct determination of paracetamol in urine intended for biopharmaceutical characterisation of drug productsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 7 2003Jelena Paroj Abstract Paracetamol is a widely used nonsalicylate analgesic and antipyretic drug. The existing methods for the determination of paracetamol in biological fluids are mainly HPLC techniques, although there are some reported methods based on spectrophotometric determinations. However, all these methods involve some extraction or derivatisation procedures. In the present study the UV spectra of investigated samples were recorded over the wavelength range 220,400 nm (, step 0.21 nm; scan speed 60 nm/min) and second-order derivative spectra were calculated. Second-order derivative spectra of different blank urine samples displayed the presence of a zero-crossing point at 245,247 nm defined as ,zc. The zero-order absorption spectra of paracetamol in water displays maximum absorbance at 243 nm, while in second derivative spectra, a minimum peak at 246 nm was observed. Therefore, the application of zero-crossing technique to the second-derivative UV absorption spectrum should be useful for the determination of paracetamol using 2D,zc. The proposed method enables determination of total paracetamol in urine directly and simply by reading the 2D,zc of the diluted samples. The obtained results were in good accordance with published data on cumulative urinary excretion after per oral administration of paracetamol obtained applying different spectrophotometric methods of determination. It could be useful for biopharmaceutical characterisation of drug products (monitoring of the levels of paracetamol in urine in bioavailability testing, for the evaluation of in vitro,in vivo correlation and screening of different formulations during drug product development). Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||||||||