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Results 551 - 600 of 3147
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Vandal Omar H - - 2008
Acidification of the phagosome is considered to be a major mechanism used by macrophages against bacteria, including Mycobacterium tuberculosis (Mtb). Mtb blocks phagosome acidification, but interferon-gamma (IFN-gamma) restores acidification and confers antimycobacterial activity. Nonetheless, it remains unclear whether acid kills Mtb, whether the intrabacterial pH of any pathogen falls when ...
Paslawski Janice C - - 2009
Naphthenic acids are a complex mixture of organic compounds which naturally occur in crude oil. Low molecular weight components of the naphthenic acids are known to be toxic in aquatic environments and there is a need to better understand the factors controlling the kinetics of their biodegradation. In this study, ...
Backhaus Claudia - - 2008
The tryptophan metabolites kynurenine, 3-hydroxykynurenine, anthranilic, 3-hydroxyanthranilic and 3-methoxyanthranilic acids were compared with regard to diazotation by .NO or NO+, using three different donors, nitrite at pH 5, PAPA-NONOate at pH 7.4 and NO+SbF(6)- at pH 2.0. With all three sources of NO species, 3-hydroxykynurenine and 3-hydroxyanthranilic acid were readily ...
Knorr Veronika - - 2008
Two types of acid-degradable nonviral gene carriers, OEI-MK and OEI-BAA, were synthesized by polymerizing oligoethylenimine of 800 Da (OEI800) with the pH-sensitive acetone ketal cross-linker 2,2-bis(N-maleimidoethyloxy) propane (MK) or the 4-methoxybenzaldehyde bisacrylate acetal cross-linker 1,1-bis-(2-acryloyloxy ethoxy)-[4-methoxy-phenyl]methane) (BAA). Corresponding acid-insensitive counterparts (OEI-BM and LT-OEI-HD) were synthesized as well, representing control polymers. ...
Feng Xiaohai - - 2010
The production of propionic acid by Propionibacterium freudenreichii CCTCC M207015 was investigated in a 7.5-l stirred-tank fermentor. Batch fermentations by P. freudenreichii CCTCC M207015 at various pH values ranging from 5.5 to 7.0 were studied. Based on the analysis of the time course of specific cell growth rate (mu (x)) ...
Valinoti Ana Carolina - - 2008
This study evaluated the effects of acidic medicines (Dimetapp and Claritin), under pH-cycling conditions, on the surface degradation of four composite resins (microhybrid: TPH, Concept, Opallis and Nanofilled: Supreme). Thirty disc-shaped specimens ([symbol: see text] = 5.0 mm/thickness = 2.0 mm) of each composite were randomly assigned to 3 groups ...
Feng Leiyu - - 2009
The effects of solids retention time (SRT) and temperature on waste activated sludge (WAS) hydrolysis and short-chain fatty acids (SCFAs) accumulation were investigated in a series of continuous-flow reactors at pH 10. The experimental results showed that the increase of either SRT or temperature benefited the hydrolysis of WAS and ...
Namani Trishool - - 2008
The first forms of cellular life required a source of amphiphilic compounds capable of assembling into stable boundary structures. Membranes composed of fatty acids have been proposed as model systems of primitive membranes, but their bilayer structure is stable only within a narrow pH range and low ionic strength. They ...
Van Damme Paul André - - 2008
Several High Andes Rivers are characterized by inorganic water pollution known as acid mine drainage (AMD). The aim of this study was to assess the relationship between metal concentrations in the sediments and the macroinvertebrate communities in two river basins affected by AMD. In general, the taxon diversity of the ...
Valdez Carlos A - - 2008
Glycosylated diazeniumdiolates of structure R 2NN(O)NO-R' (R' = a saccharide residue) are potential prodrugs of the nitric oxide (NO)-releasing but acid-sensitive R 2NN(O)NO (-) ion. Moreover, cleaving the acid-stable glycosides under alkaline conditions provides a convenient protecting group strategy for diazeniumdiolate ions. Here, we report comparative hydrolysis rate data for ...
Gosset Gaëlle - - 2008
The 31P nuclear magnetic resonance (NMR) characteristics, toxicity, and cellular penetration of five linear or cyclic alpha-aminophosphonate highly sensitive pH probes were investigated in Dictyostelium discoideum cells and isolated rat hearts and were compared with three phosphonic acid derivatives. The line width broadening at pH approximately pK(a), which was satisfactorily ...
Gethin Georgina T - - 2008
Chronic non healing wounds have an elevated alkaline environment. The acidic pH of Manuka honey makes it a potential treatment for lowering wound pH, but the duration of effect is unknown. Lowering wound pH can potentially reduce protease activity, increase fibroblast activity and increase oxygen release consequently aiding wound healing. ...
Ges Igor A - - 2008
The metabolic activity of cells can be monitored by measuring the pH in the extracellular environment. Microfabrication and microfluidic technologies allow the sensor size and the extracellular volumes to be comparable to single cells. A glass substrate with thin film pH sensitive IrO( x ) electrodes was sealed to a ...
Moon Won - - 2008
Twenty-four-hour ambulatory esophageal pH monitoring is considered the gold standard for diagnosing gastroesophageal reflux disease. The aim of this study was to quantify normal distal esophageal acid parameters in healthy Koreans. Thirty healthy adults who were not on medication and were free from gastrointestinal symptoms were analyzed. Ambulatory esophageal acid ...
Celotto A C - - 2008
Acid-base homeostasis maintains systemic arterial pH within a narrow range. Whereas the normal range of pH for clinical laboratories is 7.35-7.45, in vivo pH is maintained within a much narrower range. In clinical and experimental settings, blood pH can vary in response to respiratory or renal impairment. This altered pH ...
Chhabra Meenu - - 2008
Laccase from basidiomycete fungus Cyathus bulleri was evaluated for its ability to decolorize a number of reactive and acidic dyes in the presence of natural and synthetic mediators. The extent of decolorization was monitored at different mediator/dye concentrations and incubation time. Among the synthetic mediators, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) was effective ...
Suzuki Kingo - - 2008
In vitro studies have shown that acidic conditions impair spreading of polymorphonuclear leukocytes, which is prerequisite for activation of microbicidal functions. However, the mechanisms by which pH affects polymorphonuclear leukocytes functions remain obscure. Moreover, in vitro observations seem to contradict the fact that an acidic microenvironment often prevails at sites ...
Petrin Zlatko - - 2008
Large-scale human activities including the extensive combustion of fossil fuels have caused acidification of freshwater systems on a continental scale, resulting in reduced species diversity and, in some instances, impaired ecological functioning. In regions where acidity is natural, however, species diversity and functioning seem to be less affected. This contrasting ...
del Genio Gianmattia - - 2008
BACKGROUND: Studies have demonstrated that Nissen fundoplication controls acid gastroesophageal reflux (GER). Combined 24-h pH and multichannel intraluminal impedance (MII-pH) allows detection of both acid and nonacid GER. Antireflux surgery is considered for any patient whose medical therapy is not efficient, particularly patients with nonacid gastroesophageal reflux disease (GERD). Nevertheless, ...
Taconi Katherine A - - 2008
Operating an anaerobic digester at low pH could offer several advantages over operation at neutral pH. Most wastewater streams targeted for anaerobic digestion are inherently acidic, requiring alkalinity supplementation (at added expense) to buffer the pH at neutral. Additionally, previously published work completed by the authors using batch systems suggested ...
Tømmeraas Kristoffer - - 2008
Hyaluronic acid (HA) was hydrolyzed using varying temperatures (40, 60, and 80 degrees C) and acid concentrations (0.0010, 0.010, 0.10, 0.50, 1.0, and 2.0 M HCl). The degradation process was monitored by determination of weight average molecular weight ( M w) by size-exclusion chromatography with online multiangle laser light scattering, ...
Levin Jacquelyn - - 2008
Skin surface acidity can be measured according to two criteria, its value given by pH and its strength determined by the ability of the skin to resist an acidic/alkaline aggression (i.e. acidic/alkaline resistance and neutralization tests). It is the quantitative extent to which the skin resists these changes that defines ...
Bredenoord A J - - 2008
Impedance monitoring is a new technique that can be used to detect the flow of fluids and gas through hollow viscera. With impedance monitoring gastro-oesophageal reflux can be detected independent of its acidity by differences in electrical impedance between the mucosal surface, fluids and gas that surround the catheter. Clinically, ...
Schenk Jonas - - 2008
An on-line pH monitoring method based on mid-infrared spectroscopy relevant to bioprocesses is presented. This approach is non-invasive and does not require the addition of indicators or dyes, since it relies on the analysis of species of common buffers used in culture media, such as phosphate buffer. Starting with titrations ...
Ma Zhi-Yong - - 2008
Extracellular acidic pH-activated chloride channel I(Cl, acid), has been characterized in HEK 293 cells and mammalian cardiac myocytes. This study was designed to characterize I(Cl,acid) in human umbilical vein endothelial cells(HUVECs). The activation and deactivation of the current rapidly and repeatedly follows the change of the extracellular solution at pH ...
Koschorreck Matthias - - 2008
It is now well established that microbial sulphate-reduction can proceed in environments with a pH<5. This review summarizes existing reports on sulphate reduction at low pH and discusses possible pH effects on sulphate-reducing bacteria. Microbial sulphate reduction has been observed in acidic lakes, wetlands, mesocosms, acidic sulphate soils and bioreactors. ...
Mu Shaolin - - 2008
Poly(aniline- co-2-amino-4-hydroxybenzenesulfonic acid) (PAAHB) was first synthesized via the electrochemical copolymerization of aniline and 2-amino-4-hydroxybenzenesulfonic acid (AHB) in the presence of an ionic liquid. The conductivity of PAAHB in the oxidized state is 0.45 S cm(-1). The conductivity and ESR spectra of PAAHB are slightly affected by water. The cyclic ...
Hunt R H - - 2008
AGN 201904-Z is a new, slowly absorbed, acid-stable pro-proton pump inhibitor (pro-PPI) rapidly converted to omeprazole in the systemic circulation giving a prolonged residence time. To investigate pharmacodynamics and pharmacokinetics of AGN 201904-Z compared to esomeprazole. A randomized, open-label, parallel group, investigator-blinded intragastric pH study was conducted in 24 healthy ...
Goss Heather V - - 2008
We experimentally acidified three low alkalinity first-order streams in forested catchments in Maine, USA. We evaluated water samples from a reference site above the point of hydrochloric acid addition and from two or three sites located 16 to 94 m downstream. Neutralization included protonation of weak acids, adsorption of sulfate, ...
Khataee A R - - 2009
This study makes a comparison between UV/Nano-TiO(2), Fenton, Fenton-like, electro-Fenton (EF) and electrocoagulation (EC) treatment methods to investigate the removal of C.I. Acid Blue 9 (AB9), which was chosen as the model organic contaminant. Results indicated that the decolorization efficiency was in order of Fenton>EC>UV/Nano-TiO(2)>Fenton-like>EF. Desired concentrations of Fe(2+) and ...
Mekapati Jyothi - - 2008
BACKGROUND & AIMS: Esophageal acid exposure conventionally is measured 5 cm above the lower esophageal sphincter (LES). The aim of this study was to compare pH profiles at sites within the LES, the distal esophagus, and the proximal stomach. METHODS: Ten normal subjects underwent esophageal manometry followed by 24-hour esophagogastric ...
Mendez Monica O - - 2008
Bacterial diversity in mine tailing microbial communities has not been thoroughly investigated despite the correlations that have been observed between the relative microbial diversity and the success of revegetation efforts at tailing sites. This study employed phylogenetic analyses of 16S rRNA genes to compare the bacterial communities present in highly ...
Ross, Karen
Big Moose Lake (BML) in the Adirondack region of New York has experienced strong acidification from acidic deposition since the 1950s. These chemical changes have altered the ecosystem structure, primarily shifting the biological community towards more acid-tolerant species. Current trends in measured water chemistry suggest that the pH of BML ...
Ban Lan - - 2008
Hardwoods contain a substantial amount of hemicellulose-type oligosaccharides, the chemical structures of which are typically categorized in the xylan saccharide class. The efficient and selective isolation of these hemicelluloses is regarded as one of the most critical obstacles to overcome for their eventual biomaterial and bioenergy utilization. Therefore, the objective ...
De Witte Bavo - - 2009
A bubble reactor was used for ozonation of the antibiotic ciprofloxacin. Effects of process parameters ozone inlet concentration, ciprofloxacin concentration, temperature, pH and H(2)O(2) concentration were tested. Desethylene ciprofloxacin was identified, based on HPLC-MS analysis, as one of the degradation products. Formation of desethylene ciprofloxacin was highly dependent on pH, ...
Devincenti C V - - 2009
The myotomal fibres of the pectoral fins of white croaker (Micropogonias furnieri) have been studied using histochemical techniques and transmission electron microscopy (TEM). Succinic dehydrogenase (SDH) for mitochondria, periodic acid Schiff (PAS) for glycogen, Sudan Black for lipids and myosin-adenosintriphosphatase (mATPase) pre-incubated at alkaline and acid pHs were used to ...
Li Chi-Wang - - 2008
This study focused on the effects of pH and organic ligands, namely ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and citric acids, on the removal and recovery of Cd(II) in polyelectrolyte enhanced ultrafiltration (PEUF). Polyethylenimine (PEI), which can bind with both positively charged metal ions by coordination bonding and negatively charged ...
Ho C W - - 2008
During the production of palm sugar, the palm sap (Arenga pinnata) is heated up to 150 degrees C. Besides the hydrolysis of carbohydrate to generate reducing sugars and degradation of amino acid, many physicochemical changes produced at all these temperatures, having a significant impact on the overall quality of palm ...
Rooke J A - - 2008
Neonatal lamb mortality represents both a welfare issue (due to the considerable suffering and distress) and an important production inefficiency. In lambs, approximately 80% of mortality can be attributed to the starvation-mismothering-exposure complex and occurs in the first 3 days after birth. It was the object of this review to ...
Morris Humberto J - - 2008
Studies on enzymatic hydrolysis of cell proteins in green microalgae Chlorella vulgaris 87/1 are described. Different proteases can be used for production of hydrolysates from ethanol extracted algae. The influence of reaction parameters on hydrolysis of extracted biomass with pancreatin was considered, and the composition of hydrolysates (Cv-PH) was investigated ...
Lemaire Sandrine - - 2008
Methicillin-resistant Staphylococcus aureus (MRSA) is a global scourge, and treatment options are becoming limited. The MRSA phenotype reverts to that of beta-lactam-sensitive S. aureus when bacteria are grown at pH 5.0 in broth and, more importantly from a medical perspective (protracted, relapsing infections), after phagocytosis by macrophages, where the bacteria ...
Chekmenev Eduard Y - - 2008
We use the PASADENA (parahydrogen and synthesis allow dramatically enhanced nuclear alignment) method to achieve 13C polarization of approximately 20% in seconds in 1-13C-succinic-d2 acid. The high-field 13C multiplets are observed as a function of pH, and the line broadening of C1 is pronounced in the region of the pK ...
Tiwari B K - - 2008
The effects of sonication on pH, degrees Brix, titratable acidity (TA), cloud, browning index, and color parameters ( L*, a*, and b*) of freshly squeezed orange juice samples were studied. Ultrasonic intensity (UI) levels of 8.61, 9.24, 10.16, 17.17, and 22.79 W/cm2 and treatment times of 0 (control), 2, 4, ...
Arroyo-López F N - - 2008
The single and combined effects, in a synthetic medium at selected pH values, of sorbic and benzoic acids on a yeast cocktail (Saccharomyces cerevisiae, Pichia anomala, Issatchenkia occidentalis, and Candida diddensiae, isolated from table olives) have been studied. Applying the checkerboard method the minimum inhibitory concentration (MIC) obtained for the ...
Martínez-Otero Alberto - - 2008
In this letter, we report on the development of a surface molecular sensor for the detection of acidity. Lithographically controlled wetting deposition has been applied to form the nanostructure of a new fluorescent compound with three protonation states featuring different optical properties on a glass substrate. Atomic force microscopy demonstrates ...
Lee Soyoung - - 2008
We determined the partial molar volumes, V degrees , and adiabatic compressibilities, K degrees (S), of N-acetyl amino acids with neutralized carboxyl termini, N-acetyl amino acid amides, and N-acetyl amino acid methylamides between 18 and 55 degrees C. The individual compounds in the three classes have been selected so as ...
El Hage Tatiana - - 2008
A detailed proteolysis study of internalized diphtheria toxin (DT) within rat liver endosomes was undertaken to determine whether DT-resistant species exhibit defects in toxin endocytosis, toxin activation by cellular enzymes or toxin translocation to its cytosolic target. Following administration of a saturating dose of wild-type DT or nontoxic mutant DT ...
Burgett Randy A - - 2008
The nitrone, 5,5-dimethylpyrroline N-oxide (DMPO), is a commonly used spin trap for the detection of superoxide radical anion (O2*-) using electron paramagnetic resonance spectroscopy. This work investigates the reactivity of DMPO to O2*- in mildly acidic pH (5.0-7.0). Mild acidity is characteristic of acidosis and has been observed in hypoxic ...
Störmer Melanie - - 2008
BACKGROUND: The platelet (PLT) storage lesion is characterized metabolically by a pH value associated with lactic acid generation. PLT storage conditions support the growth of Staphylococcus epidermidis, the most common organism implicated in bacterial contamination of PLT concentrates (PCs). Here, different factors that influence bacterial growth in PCs are discussed ...
Bussink Anton P - - 2008
Mammals express two active chitinases, chitotriosidase and AMCase. Only AMCase displays an extremely acidic pH optimum, consistent with its observed presence in the gastro-intestinal tract. A structural model of AMCase reveals the presence of a conserved histidine residue in the active site. Mutational analyses and molecular dynamics simulations show that ...
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