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Acid Aqueous Solution (acid aqueous + solution)
Selected AbstractsStimulation of epidermal calcium gradient loss and increase in TNF-, and IL-1, expressions by glycolic acid in murine epidermisEXPERIMENTAL DERMATOLOGY, Issue 8 2005Se Kyoo Jeong Abstract:, In a previous study, we reported that ,-hydroxy acids (AHA), such as glycolic acid and lactic acid, did not induce any significant changes in transepidermal water loss for normal murine skin. The ultrastructural observations, however, showed that the extent of lamellar body exocytosis significantly increased. Because AHA can theoretically decrease the calcium ion concentration by chelation, topical AHA may induce the loss of epidermal calcium gradient by lowering the calcium ion concentration in the granulocytes and, subsequently, induce lamellar body secretion. The aim of this study is to verify that glycolic acid could modulate the epidermal calcium gradient and increase lamellar body exocytosis. Seventy per cent of glycolic acid aqueous solution was applied to the normal skin of hairless mice and biochemical and morphological studies were performed. The loss of epidermal calcium gradient was observed in glycolic-acid-applied skin of hairless mice and subsequent barrier function recovery processes, such as an increase in lamellar body secretion, were observed. The extracellular glycolic acid was found to inhibit the change in intracellular calcium ion concentration in response to extracellular calcium ion concentration changes in the cultured mouse keratinocyte in vitro. The protein and mRNA expressions of tumour necrosis factor-, and interleukin-1, in the murine epidermis were significantly increased after glycolic acid application. An in vitro study using cultured keratinocytes suggested that glycolic acid could lower the calcium ion concentration, at least in part, through the chelating effects of the glycolic acid on the cationic ions. [source] Methodology Optimization for Quantification of Total Phenolics and Individual Phenolic Acids in Sweetpotato (Ipomoea batatas L.) RootsJOURNAL OF FOOD SCIENCE, Issue 7 2007M.S. Padda ABSTRACT:, Phenolic acids are one of the several classes of naturally occurring antioxidant compounds found in sweetpotatoes. Simplified, robust, and rapid methodologies were optimized to quantify total and individual phenolic acids in sweetpotato roots. Total phenolic acid content was quantified spectrophotometrically using both Folin,Denis and Folin,Ciocalteu reagents. The Folin,Ciocalteu reagent gave an overestimation of total phenolic acids due to the absorbance of interfering compounds (that is, reducing sugars and ascorbic acid). Individual phenolic acids were quantified by high-performance liquid chromatography (HPLC) using the latest in column technology. Four reversed-phase C18 analytical columns with different properties (dimensions, particle size, particle shape, pore size, and carbon load) were compared. Three different mobile phases using isocratic conditions were also evaluated. A column (4.6 × 150 mm) packed with 5-,m spherical silica particles of pore size 110 Å combined with 14% carbon load provided the best and fast separation of individual phenolic acids (that is, chlorogenic acid, caffeic acid, and 3 isomers of dicaffeoylquinic acid) with a total analysis time of less than 7 min. Among the 3 mobile phases tested, a mobile phase consisting of 1% (v/v) formic acid aqueous solution: acetonitrile: 2-propanol, pH 2.5 (70:22:8, v/v/v) gave adequate separation. Among the solvents tested, aqueous mixtures (80:20, solvent:water) of methanol and ethanol provided higher phenolic acid extraction efficiency than the aqueous mixture of acetone. [source] Simultaneous determination of yohimbine, sildenafil, vardenafil and tadalafil in dietary supplements using high-performance liquid chromatography-tandem mass spectrometryJOURNAL OF SEPARATION SCIENCE, JSS, Issue 14 2010Ying Zhang Abstract A simple and sensitive method was developed for determination of illegal adulterants (yohimbine, sildenafil, vardenafil and tadalafil) in dietary supplements by HPLC-MS/MS. The separation was achieved on a C18 column with the mobile phase consisting of acetonitrile and 0.1% acetic acid aqueous solution with a gradient elution at a flow rate of 0.5,mL/min. The analytes were quantified and identified by two characteristic transitions using the multiple-reaction monitoring mode. The recoveries of the analytes ranged from 77.5 to 109.3% with the RSD less than 8.1% (n=6). The method has been successfully applied to screen illegal adulterations of natural dietary supplements. [source] Robust Organic/Inorganic Hybrid Porous Thin Films via Breath-Figure Method and Gelation ProcessMACROMOLECULAR RAPID COMMUNICATIONS, Issue 20 2007Ke Zhang Abstract A novel organic/inorganic hybrid honeycomb patterned porous thin film was prepared using the breath-figure method combined with a sol-gel process. An in situ formed gelable block copolymer, formed by mixing poly(styrene- alt -maleic anhydride)- block -polystyrene (P(St- a -MAn)- b -PS) and 3-aminopropyltrimethoxysilane (APS), was used as the structure directing agent. The porous film produced was dipped into an acid aqueous solution to induce a sol-gel process in the wall of film. As a result of gelation, the structure of this film transformed into a crosslinked silica oxide hybridized with PS, and this film resisted those organic solvents which were once good solvents for the copolymer precursor. [source] Porous anodic alumina thin films on Si: interface characterizationPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2008V. Gianneta Abstract Porous anodic alumina (PAA) thin films (thickness , 50nm) were fabricated on Si by anodization of thin Al films under constant voltage of 20 V in sulphuric acid aqueous solution. The films exhibit cylindrical vertical pores of diameter , 13,15 nm, arranged in hexagonal close packed structure. Electrochemical oxidation of the Si substrate through PAA, used as masking layer with openings in the pores, resulted in the formation of SiO2 dots at each pore tip. Two different kinds of films, namely with or without SiO2 dots at pore tips, were fabricated. In order to characterize the electrical quality of the interface of PAA thin films with Si, C-V and G-V measurements were performed on Metal-Insulator-Semiconductor (MIS) structures with Al metallization. The measurements were carried out in the voltage range +1.0 V to ,3.0 V in steps of 0.05 V and in the frequency range 1 MHz to 100 Hz. The typical form of C-V and G-V curves of a MIS structure was obtained. In order to determine the interface trap density Dit, C-f and G-f measurements were performed as a function of the applied gate voltage in the depletion region. Dit was evaluated following the Conductance Method (E. H. Nicollian, and J. R. Brews, MOS Physics and Technology (J. Wiley & Sons, New York, 1982), p. 222 [1]). Both types of samples exhibit values of Dit in the order of 1011 eV,1cm,2. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Microstructure of nanopores in AAO templates favoring the growth of nickel nanowires by electrodepositionPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2007Jong-Hyun Jeong Abstract Morphology of periodical nanoscale pores in AAO templates has been studied in relation with anodizing process, focusing on the growth of nickel nanowires by electrochemical deposition. The AAO templates were prepared by a two-step anodization process. The high purity aluminum plates were anodized in oxalic acid aqueous solution with variation of cell voltage. The pore size and interpore distance both increase with the applied potential. During the post treatment of barrier thinning, small-size pores with split-up structure at the tips are observed due to current-limited anodizing process (decreasing cell potential). The rectifying properties of the barrier layer allow the pores to be filled by nickel by AC electrodeposition. The nickel nanowires array shows the ferromagnetic properties with a preferred magnetic orientation along the wire axis. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preparation of porous biodegradable microspheres with direct melting dispersion methodPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 4 2007Yoshinari Taguchi Abstract Porous biodegradable microspheres can be prepared by using the direct melting dispersion method without any noxious organic solvents, in which the biodegradable polymer is directly melted and stirred to form the liquid,liquid dispersion followed by cooling in the continuous phase, such as ethylene glycol with the higher melting temperature than polymer. In the experiment, polyhydroxybutyrate (PHB) was adopted as the biodegradable polymer. As particulate porogen, magnetite powder was pre-mixed into the melted polymer and removed by hydrochloric acid aqueous solution after preparation of the microspheres to make them porous. It was found that the inner surface area was significantly increased by removing magnetite powder. Copyright © 2007 John Wiley & Sons, Ltd. [source] The Use of Electrolyzed Solutions for the Cleaning and Disinfecting of DialyzersARTIFICIAL ORGANS, Issue 12 2000Noriaki Tanaka Abstract: Recently, the use of electrolyzed solutions has attracted considerable interest in Japan. This study investigates the efficiency of electrolyzed solutions as disinfecting agents (DA) in the reuse of dialyzers and compares their efficiency to that of other disinfectants currently in use. The following 3 methods were employed. First, the rinsing time and rebound release of reused dialyzers were measured and compared after electrolyzed solutions, electrolyzed strong acid aqueous solution (ESAAS) and electrolyzed strong basic aqueous solution (ESBAS), made from reverse osmosis (RO) water (ESAAS, ESBAS; Generating apparatuses: Super Oxseed , 1000, Amano Corporation, Yokohama, Japan), 2% Dialox-cj (Teijin Gambro Medical, Tokyo, Japan), and 3.8% formalin were used as DAs. This involved performing dialysis with 2 types of dialyzers: a cellulose acetate membrane (CAM) dialyzer and a polysulfone membrane (PSM) dialyzer. The dialyzers were cleaned and disinfected using the different DA and left for 48 h. Next, after performing dialysis the dialyzer membranes were cleaned with a saline solution (0.9% NaCl) and RO water and then cleaned with the various DA. These membranes were observed using a scanning electron microscope (SEM) to check for the presence of physical and biological contaminants. Finally, in vitro tests were performed to determine the level of dialyzer clearance when PSM dialyzers were reused after having been cleaned and disinfected with the electrolyzed solutions. The rinsing time results for both the CAM and PSM dialyzers showed the electrolyzed solutions (ESBAS and ESAAS) as being undetectable within 10 min. With regard to the rebound release, for both the CAM and PSM dialyzers, the electrolyzed solutions were undetectable at all checking times between 30 and 240 min. Observation by SEM showed that cleaning with both ESAAS and ESBAS left the fewest contaminants, and cleaning with 2% Dialox-cj left the highest level of contaminants in the CAM dialyzers. With regard to experiments concerning use in vitro, no major changes in the dialyzer clearance were noticed after 6 uses. In every experiment, the previous investigations showed the electrolyzed solutions to be superior to 3.8% formalin and 2% Dialox-cj DA for the reuse of dialyzers. [source] Quantitative determination of capsaicin, a transient receptor potential channel vanilloid 1 agonist, by liquid chromatography quadrupole ion trap mass spectrometry: evaluation of in vitro metabolic stabilityBIOMEDICAL CHROMATOGRAPHY, Issue 2 2009Francis Beaudry Abstract Capsaicin is the most abundant pungent molecule present in red peppers and it is widely used for food flavoring, in pepper spray in self-defense devices and more recently in ointments for the relief of neuropathic pain. Capsaicin is a selective agonist of transient receptor potential channel, vanilloid subfamily member 1. A selective and sensitive quantitative method for the determination of capsaicin by LC-ESI/MS/MS was developed. The method consisted of a protein precipitation extraction followed by analysis using liquid chromatography electrospray quadrupole ion trap mass spectrometry. The chromatographic separation was achieved using a 100 × 2 mm C18 Waters Symmetry column combined with a gradient mobile phase composed of acetonitrile and 0.1% formic acid aqueous solution at a flow rate of 220 µL/min. The mass spectrometer was operating in full-scan MS/MS mode using two-segment analysis. An analytical range of 10,5000 ng/mL was used in the calibration curve constructed in rat plasma. The interbatch precision and accuracy observed were 6.5, 6.7, 5.3 and 101.2, 102.7, 103.5% at 50, 500 and 5000 ng/mL, respectively. An in vitro metabolic stability study was performed in rat, dog and mouse liver microsomes and the novel analytical method was adapted and used to determine intrinsic clearance of capsaicin. Results suggest very rapid degradation with T1/2 ranging from 2.3 to 4.1 min and high clearance values suggesting that drug bioavailability will be considerably reduced, consequently affecting drug response and efficacy. Copyright © 2008 John Wiley & Sons, Ltd. [source] Film-forming process and biocide assessment of high-molecular-weight chitosan as determined by combined ATR-FTIR spectroscopy and antimicrobial assaysBIOPOLYMERS, Issue 6 2006P. Fernandez-Saiz Abstract This pioneering study reported about the film-forming properties of high-molecular-weight chitosan as followed in situ by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, and has implications in fields such as biomedical, pharmaceutical, packaging, and coating applications. From the results, it was observed that immediately after dissolution in an acetic acid aqueous solution and subsequent casting over the ATR crystal, the formed carboxylate antimicrobial (NH,OOCH) species are not stable in the film formulation and become reduced over time; further assays confirmed previous research, which suggested that the presence and stability of these groups is strongly dependent, among other factors, on storage conditions. As-received chitosan and chitosan neutralized in NaOH films did not exhibit biocide performance towards Staphylococcus aureus. The antimicrobial tests were also found to strongly relate the presence of a sufficient quantity of these carboxylate groups to the chitosan activity as a biocide agent. Moreover, a novel methodology based on the use of a normalized infrared band centered at 1405 cm,1 is proposed which can be correlated with the antimicrobial character of the biopolymer. © 2006 Wiley Periodicals, Inc. Biopolymers 83: 577,583, 2006 This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] | ||||||||||||||||