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Results 451 - 500 of 1636
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Cheng Yu - - 2005
A nonderivatization analytical method has been developed to analyze C6-C20 fatty acids and cis-pinonic acid on a GC/ FID and a GC/MSD using a polar DB-FFAP capillary column. On the GC/FID, the response was highly linear over concentration ranges >2 orders of magnitude (R2 = 1.00). Using a mixed solvent ...
Zhang X - - 2005
Analysis of dyes extracted from textiles of historical interest can give valuable information as to where, when, and how the textiles were made. The most widely used method for extraction of colorants involves heating with HCl, which frequently decomposes glycosidic dye components to their parent aglycons, with consequent loss of ...
Bernárdez Marta - - 2005
The objective of this study was the development of a method for the quantification of free fatty acids (FFA) using less aggressive reactants against the handler and the environment than those used in the classic method of Lowry and Tinsley. The modified procedure is a variation of the Lowry and ...
Ramazotti-Ferrati Anali - - 2005
Several alternative analytical methods are currently available for the rapid microbiological testing of food. Due to their many advantages, particularly their convenience of use, the popularity of ready-to-use systems for the enumeration of hygiene indicator microorganisms is increasing. However, the ability of these systems to enumerate stressed microorganisms, such as ...
Anttila Piia - - 2005
LC-MS methods with use of ion-trap and time-of-flight mass spectrometers were developed for the determination of organic acids in aerosol samples collected by a high-volume sampler in a Finnish coniferous forest. Comparison was made of the composition of samples collected during atmospheric formation of new aerosol particles and on days ...
Ferreira Vanda S - - 2005
A comparative study of rubber sheets obtained using formic, acetic, and smoke acid as coagulants is shown for latex obtained from native Amazonian trees and also from commercial cultivated trees. The evaluation of both processes of coagulation was carried out by spectroscopic and physical-chemical analysis, showing no differences in the ...
Chou Hardy J - - 2005
A liquid chromatography (LC) method using a thermal energy analyzer (TEA) is described for the determination of diethanolamine (DEA) in shampoo products containing fatty acid diethanolamides. DEA was converted to N-nitrosodiethanolamine (NDELA) by dissolving a portion of the product in 6M acetic acid and mixing with sodium nitrite for 1 ...
Matsushita Yasuyuki - - 2005
In order to effectively utilize a by-product of the acid saccharification process of woody materials, the chemical conversion of guaiacyl sulfuric acid lignin (SAL), one of the acid hydrolysis lignins, into water-soluble sulfonated products with high dispersibitity was investigated. At first, SAL was phenolated (P-SAL) to enhance the solubility and ...
Li Hui - - 2005
An ultrasonic method for the extraction of chlorogenic acid from fresh leaves of Eucommia ulmodies Oliv. was investigated and optimized. The influence of four extraction variables on extraction efficiency of chlorogenic acid was investigated. The optimum extraction conditions found were: 70% aqueous methanol; solvent: sample ratio=20:1 (v/w); extraction time 3 ...
Suárez Belén - - 2005
An analytical method for the quantitative determination of the principal phenolic compounds (benzoic acids, hydroxycinnamic acids, 3-phenylpropionic acids, flavanols, procyanidins, dihydrochalcones, quercetin glycosides) in ciders, which successfully employs a RP-HPLC and photodiode-array detection system without prior treatment of the sample, is described. Parameters usually examined in the method validation were ...
Agarwal Lata - - 2005
Succinic acid, an intermediate of tricarboxylic acid cycle, is produced and accumulated by anaerobic microorganisms. The long-standing interest in the production of this organic acid is because it is a key compound in producing more than 30 commercially important products. The detection of succinic acid is generally carried out by ...
Wang Jun - - 2005
A new analytical method for the determination of uric acid (UA) by the perturbation of UA on the Belousov-Zhabotinsky oscillating reaction is proposed. The method is based on the linear relationship between the changes in the oscillating period and the concentration of UA. The calibration curve is linear over the ...
Corona-Avendaño S - - 2005
The present work aimed at describing the spectral behaviour of the serotonin and to evaluate its acidity constants using three different methods, using two spectrophotometry titrations and a third method that involved point-by-point analysis, which permitted to monitor closely and determine the evolution of the serotonin species in solution as ...
Townshend Alan - - 2005
A flow injection method is proposed for the determination of naftopidil based upon the oxidation by potassium permanganate in a sulfuric acid medium and sensitized by formaldehyde and formic acid. The optimum chemical conditions for the chemiluminescence emission were 0.25 mM potassium permanganate and 4.0 M sulfuric acid. Two manifolds ...
Domínguez-González Raquel - - 2005
A new method using diluted reagents (nitric and hydrochloric acids and oxygen peroxide) and ultrasound energy to assist metals acid leaching with from edible seaweed was optimized. The method uses a first sonication at high temperature with hydrochloric acid as a previous stage to an ultrasound-assisted acid leaching with 7ml ...
Pearce R A - - 2005
AIMS: The aim of this research was to compare excision sampling with polyurethane and cellulose acetate sponge swabbing for the recovery of total viable counts and Enterobacteriaceae on meat carcasses. METHODS AND RESULTS: Two sample types were used to compare the methods: (i) individual samples, taken from four sites on ...
Lanoiselet V M - - 2005
Two fatty acid analysis protocols (the MIDI and a modified MIDI method) were investigated for their utility to characterize and differentiate Rhizoctonia oryzae and R. oryzae-sativae isolates from four countries. Only the modified MIDI method permitted a clear differentiation between the two species, regardless of the isolates' country of origin. ...
Gousterova A - - 2005
AIMS: The aim of this study was to develop a method for microbial degradation of indigenous keratin wastes and to compare it with a method of alkaline hydrolysis. METHODS AND RESULTS: Native sheep skin and wool were chosen as a model mixture of collagen and keratin wastes discarded by the ...
Deng Chunhui - - 2005
Analysis of amino acids in blood samples is an important tool for the diagnosis of neonatal amino acid metabolism disorders. In the work, a novel, rapid and sensitive method was developed for the determination of amino acids in neonatal blood samples, which was based on microwave-assisted silylation followed by gas ...
Lücker Ernst - - 2005
To elucidate the risk of occupational exposure to the agent of transmissible spongiform encephalopathies (TSE) in the histological working environment, we assessed the principal suitability of three analytical methods for the detection of tissues of the central nervous system (CNT). We tested a neuron-specific enolase (NSE) Western blot, a glial ...
Serra F - - 2005
Due to the ever-increasing amount of attention paid to the 'naturalness' of ingredients in food and beverages by both consumers and controlling authorities, the search for suitable methods for the characterisation of origin is of primary importance. Within the European Community the wine production industry is often faced with the ...
Goel A - - 2005
OBJECTIVE: Evaluation of visual inspection of the cervix with acetic acid (VIA) for screening cervical intraepithelial neoplasia. METHODS: In this prospective study, 400 women were screened using the Papanicolaou (PAP) smear, VIA and colposcopy. Those who had positive results with any of the screening methods underwent large loop excision of ...
Peris-Vicente J - - 2005
A direct infusion mass spectrometry method for the characterization of proteinaceous glues from binding media used in pictorial works of art prior to conservation or restoration treatment is proposed. Amino acids are released by acid hydrolysis and dissolved in a mixture of acidic water and ethanol. This mixture is directly ...
Jang Dong-Jin - - 2005
A high-performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of niflumic acid and its prodrug, talniflumate, in human plasma. Niflumic acid and talniflumate were eluted isocratically with methanol-water (73:27, v/v, adjusted to pH 3.5 by acetic acid) at a fl ow rate of 1 mL/min. Indomethacin ...
Kang Jing X - - 2005
BACKGROUND: Analysis of fatty acid composition of biological materials is a common task in lipid research. Conventionally, preparation of samples for fatty acid analysis by gas chromatography involves two separate procedures: lipid extraction and methylation. This conventional method is complicated, tedious and time consuming. Development of a rapid and simple ...
Savickas Ar┼źnas - - 2005
To determine experimentally the optimal limits of excipients (silica colloidal anhydrous, magnesium stearate, potato starch, saccharose), which would determine the following technological properties of the tablets: sticking of the mass to the puansons, crushing strength, resistance to abrasion-off and the speed at which medicinal substances are released from the tablets. ...
Luner Paul E - - 2005
The objective of this study was to use diffuse reflectance near infrared spectroscopy (NIRS) to determine racemic compound content in physical mixtures composed primarily of the enantiomorph and to assess the error, instrument reproducibility and limits of detection (LOD) and quantification (LOQ) of the method. Physical mixtures ranging from 0 ...
Naja Ghinwa - - 2005
The high-resolution potentiometric titration was used as a physico-chemical method to study the acid properties of selected biosorbent materials in order to quantify the functional acidic groups for sorption and to determine their affinities by considering their partial or total ionization equilibrium reactions. The Gran's method and the Henderson-Hasselbach's equation ...
Van Hemelrijck An - - 2005
Microdialysis coupled to liquid chromatography (LC) has proven to be a valuable in vivo sampling technique for studying neurotransmitter changes in normal and ischaemic brain. However, few analytical methods have described the simultaneous determination of amino acids, relevant in stroke research, together with the nitric-oxide-related compound citrulline. Therefore, we developed ...
Keller Nicolas - - 2005
A highly flexible method for direct and quantitative determination of surface Brønsted acidity of solids in terms of number, type and strength of the acid sites based on quantitative H/D exchange kinetics between the acid solid and gaseous D2O has been developed and applied to materials covering the whole range ...
Li Yin - - 2004
This Mini-Review summarizes the historic developments and technological achievements in the biotechnological production of glutathione in the past 30 years. Glutathione is the most abundant non-protein thiol compound present in living organisms. It is used as a pharmaceutical compound and can be used in food additives and the cosmetic industries. ...
Zhao Jinsheng - - 2004
The changes in intracellular redox activity or in mitochondrial electron transport could be taken as indications of the changes in the physiological state of living cells, based on which a mediated electrochemical method was purposed to evaluate the inhibitory effects of weak acids on Zygosaccharomyces bailii, a known food spoilage ...
Yeboah-Manu Dorothy - - 2004
We evaluated four decontamination methods and one nondecontamination procedure in combination with four egg-based media for the primary isolation of Mycobacterium ulcerans from tissue specimens. With mycobacterial recovery and contamination rates of 75.6 and 2.4%, respectively, the combination of the oxalic acid decontamination method with Lowenstein-Jensen medium supplemented with glycerol ...
Liang Yao-Dong - - 2004
A flow-injection chemiluminescence (CL) method for the determination of pipemidic acid is described. It is based on energy transfer from excited state peroxynitrous acid to pipemidic acid, in which the excited state peroxynitrous acid is synthesized on-line by the mixing of acid hydrogen peroxide with nitrite in a flow system ...
Gudej Jan - - 2004
This paper describes the quantitative determination of flavonoids, tannins and ellagic acid in the leaves from wild and cultivated variations of Rubus L. species (Rosaceae): raspberry (2 wild and 13 cultivars) and blackberry (3 wild and 3 cultivars). The content of flavonoids was analyzed using spectrophotometric (the Christ-Mullers method) and ...
Rao Sanath - - 2004
BACKGROUND: The common causes of textile dermatitis are formaldehyde resins and disperse dyes. There are various methods to detect the presence of formaldehyde in clothing. AIM: To detect the presence of formaldehyde in various types of textiles by the chromotropic acid method and to assess the effect of washing on ...
Yan Hui-Juan - - 2004
The electrical property of a self-assembled monolayer (SAM) of mercaptohexadecanoic acid (HS-C15H30-COOH) has been investigated with a tunneling junction confined in a capillary. This capillary method can shun the interference of vacuum gap. The contact area can be determined according to the diameter of capillary. The nonlinear current-voltage curve and ...
Yamashita Nobuyoshi - - 2004
Perfluorinated acids (PFAs) and their salts have emerged as an important class of global environmental contaminants. Determination of sub-parts-per-trillion or parts-per-quadrillion concentrations of perfluorinated acids in aqueous media has been impeded by relatively high background levels arising from procedural or instrumental blanks. To understand the role of the oceans in ...
Hsiao Hsien-Yi - - 2004
A simple spectrophotometric method is proposed for determining deacetylation degrees (DD) of chitinous materials using phosphoric acid as the UV-transparent solvent system. Calibrating by the extinction coefficients (A(210)) of D-glucosamine and N-acetyl-D-glucosamine, DD values (24-88%) were computed numerically. The results correlated well (R(2) = 0.9805, n = 50) with those ...
Aliero, BL; Department of ...
Effects of different treatment methods on the germination of seeds of <I>Parkia biglobosa</I> (mimosaceae) were carried out. Prior treatment of seeds with sulphuric acid, wet heat and mechanical scarification were found to induce germination of the dormant seeds. These methods could be applied to raise seedlings of the plant for ...
Hseu Zeng-Yei - - 2004
The production and application of compost potentially contaminate the environment with heavy metals. The heavy metal contents of composts must be exactly determined. Therefore, this study aims to understand the heavy metal contents in composts, using different digestion methods and to recommend the most appropriate digestion method making this measurement. ...
Choi Young Hae - - 2004
The determination of ginkgolic acids in Ginkgo products is one of the principal components of quality control. However, a number of ginkgolic acids with different side chains may be present and this makes their analysis by conventional chromatographic methods more complex. In this study, 1H-NMR spectrometry was applied to the ...
Lachenal Dominique - - 2004
Lignin in kraft pulp was extracted by enzymatic hydrolysis of the carbohydrates, acidolysis with dioxane-water-HCl (conventional method), and acidolysis with acetic acid-water-ZnCl2. The latter method was shown to extract lignin with a better yield than for conventional acidolysis and with a much lower content in impurities than for enzymatic hydrolysis. ...
Oszczapowicz Irena - - 2004
A new method of isolation of cefetamet pivoxil, which results in higher purity and higher yield than according to the known methods, was worked out. The new method depends on ability to the adsorption on acidic active carbon of total amount of this antibiotic together with only a small amount ...
Rusin Oleksandr - - 2004
The detection of saccharides in biological media is of great current importance for the monitoring of disease states. We have previously reported that solutions of boronic acid-functionalized macrocycles form acyclic oligomeric materials in situ. The oligomers contain fluorescent xanthene moieties. Current efforts are aimed at modulating the spectroscopic responses of ...
Boldrup Linda - - 2004
A stopped assay for fatty acid amide hydrolase (FAAH) has been developed, whereby the enzyme reaction product ([(3)H]ethanolamine) was separated from substrate (anandamide [ethanolamine-1-(3)H]), by differential adsorption to charcoal. The assay gave a better extraction efficiency when acidic rather than alkaline charcoal solutions were used to stop the reaction, and ...
Neville David C A - - 2004
Interest in cellular glycosphingolipid (GSL) function has necessitated the development of a rapid and sensitive method to both analyze and characterize the full complement of structures present in various cells and tissues. An optimized method to characterize oligosaccharides released from glycosphingolipids following ceramide glycanase digestion has been developed. The procedure ...
Leung Yuk-Yuen Max - - 2004
OBJECTIVES: To develop a noninvasive method to measure urinary flow rate in the mouse. This could be useful for the study of bladder outlet obstruction, as well as processes affecting detrusor function in the awake animal. Genetically engineered mice can improve our understanding of a variety of human bladder diseases. ...
Rejeb Ines Ben - - 2004
A new method for lipase activity determination is described, in which liberation of fatty acids by lipase-catalyzed hydrolysis is coupled to lipoxygenation. The second reaction forms hydroperoxy-fatty acids containing a conjugated double bond that are detected at 234 nm. The method is sensitive, cheap and easy to use when compared ...
Stadtländer Christian T K-H - - 2004
This paper reports our experiences with preparing delicate biological specimens for scanning electron microscopy. Three different washing methods were evaluated: One method allowed the analysis of the location of the bacterium Mycoplasma mobile on piscine gill epithelium and the optimal evaluation of histopathologic changes caused by this microbe. These results ...
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