Tailor-made, pH-controlled matrix minitablets based on different HPMC types were developed comprising the weakly basic drug dipyridamole. The incorporation of pH modifiers, i.e., fumaric and succinic acid, enhanced the drug release at pH 6.8. Assessing the drug release, acid release, and the microenvironmental pH (pHM) provided detailed understanding of pH-controlled ...

The effect of chromium (Cr) stress on the changes of rhizosphere pH, organic acid exudation, and Cr accumulation in plants was studied using two rice genotypes differing in grain Cr accumulation. The results showed that rhizosphere pH increased with increasing level of Cr in the culture solution and with an ...

MarA, a transcriptional regulator in Escherichia coli, affects functions such as multiple-antibiotic resistance (Mar) and virulence. Usually an activator, MarA is a repressor of hdeAB and other acid resistance genes. We found that, in wild-type cells grown in LB medium at pH 7.0 or pH 5.5, repression of hdeAB by ...

Lakes formed because of coal mining are characterized by low pH and high concentrations of Fe(II) and sulfate. The anoxic sediment is often separated into an upper acidic zone (pH 3; zone I) with large amounts of reactive iron and a deeper slightly acidic zone (pH 5.5; zone III) with ...

Batch leaching studies on chromite ore processing residue (COPR) were performed using acids to investigate leaching of hexavalent chromium, Cr(VI), with respect to particle size, reaction time, and type of acid (HNO(3) and H(2)SO(4)). Aqueous Cr(VI) is maximized at approximately 0.04 mol Cr(VI) per kg of dry COPR at pH ...

We used the pH-sensitive dye BCECF to evaluate the effect of acute (5-10 min) hypoxia (approximately 3% O(2)) on the regulation of intracellular pH (pH(i)) in astrocyte populations cultured from rat hippocampus. For cells in the nominal absence of CO(2)/HCO(3)(-) at an extracellular pH of 7.40 (37 degrees C), acute ...

AIMS: It has been proposed that intracellular acidosis may be the basis of the cardioprotection of different interventions, including postconditioning. However, contradictory reports exist on the effects of acidic reperfusion on myocardial salvage. Here we characterized the effect of lowering the pH of the reperfusion media (pHo) on intracellular pH ...

Thesis (Ph. D. in Medical Sciences)--University of Tsukuba, (A), no. 2387, 2000.3.24

Seven-year-old beech seedlings (Fagus crenata) were exposed to simulated acid fog (SAF) at pH 3 or pH 5 (as control) prepared by adding a 2:1:1 mixture (molar ratio) of nitric acid, ammonium sulfate, and sodium chloride to ultrapure water from September 2004 to July 2006 in a mobile fog chamber. ...

The responses of larval Aedes aegypti to media of pH 4, 7 and 11 provide evidence for pH regulatory strategies. Drinking rates in pH 4 media were elevated 3- to 5-fold above those observed in pH 7 or 11. Total body water was elevated during acute exposure to acidic media. ...

For the purpose of quality evaluation of commercially available magnesium oxide (MgO) tablets, we studied their acid neutralization and dissolution behaviors. The dissolution test was carried out by the paddle method in 1st fluid (pH 1.2). The dissolution amount of MgO from tablets was determined by chelatometric titration. The medium ...

AIM: To identify feeding and management variables associated with variation in faecal pH within a population of intensively managed Thoroughbred racehorses in New Zealand. METHODS: A cross-sectional survey was conducted of 16 racehorse trainers in the North Island of New Zealand. Interviews were conducted at the trainers' stables to obtain ...

Chitosan resins modified with amino acids, such as glycine, valine, leucine, and serine, were synthesized for investigating the adsorption behavior of cationic and anionic species, and showed good abilities for the adsorption of trace elements in aquatic media as follows: glycine for lanthanoids at pH 7, leucine for molybdenum at ...

Zero-valent iron (Fe0) is frequently used for the dechlorination of pesticides, because it is economical, easily acquired and stable. The kinetics of dechlorination by Fe0 are improved at low pH, but this requires additional acid addition, while dechlorination hardly occurs under basic conditions. Due to the buffer capacity of geological ...

The influence of propylen glycol (PG), ethanol, and oleic acid (OA) on nortriptyline hydrochloride (NTH) penetration through human epidermis was studied in vitro at two different pH values (5.5 and 7.4). The influence of lactic acid and polysorbate 80 was studied for a pH of 5.5. Permeation studies through Heat ...

The effective quantum yield of photochemical energy conversion in photosystem II (Phi2) was shown to be reduced in the terricolous lichens Cetraria aculeata and Cetraria islandica by short-term exposure to aqueous SO2 at pH values occurring in the precipitation of areas with high SO2 pollution. Significant reduction of Phi2 was ...

The use of sulfate-reducing bacteria (SRB) is a cost-effective route to treat sulfate- contaminated waters and precipitate metals. The isolation and characterization of a SRB strain from an AMD in a Brazilian tropical region site was carried out. With a moderately acidic pH (5.5), the C.1 strain began its growth ...

As the key regulator of apoptosis, Bcl-2 family protein controls the cell death by forming homo- or heterodimers among anti-apoptotic and pro-apoptotic members of this family. Here we have studied Bcl-x(L) homodimerization at different pH in the presence of various detergents and organic solvents. We found that both acidic and ...

Agrobacterium tumefaciens transferred DNA (T-DNA) transfer requires that the virulence genes (vir regulon) on the tumor-inducing (Ti) plasmid be induced by plant phenolic signals in an acidic environment. Using transcriptome analysis, we found that these acidic conditions elicit two distinct responses: (i) a general and conserved response through which Agrobacterium ...

For accelerating the purification process development of human monoclonal antibodies (hmAbs) for pharmaceutical drugs, we designed a standardized method for setting the conditions of the purification process, which could be applied to hmAbs for the early phase of pharmaceutical development. The process includes three sequential chromatography steps: Protein A affinity ...

The classical transient receptor potential channel 5 (TRPC5) is a molecular candidate for nonselective cation channel (NSCC) activated by muscarinic receptor stimulation whereas extracellular pH inhibits or enhances NSCC activated by muscarinic receptor stimulation depending on extracellular cation compositions in native tissues. We investigated the effect of extracellular pH on ...

Protein, lipid, and insolubles (bones, skin, scales, fins, insoluble protein, and more) were recovered from rainbow trout processing by-products by means of isoelectric solubilization/precipitation at basic pH and acidic pH. Isoelectric solubilization/precipitation of the trout processing by-products resulted in the recovery of protein that was higher (P < 0.05) in ...

Mung bean was investigated as a novel source of lipoxygenase in the natural production of the green-note aroma compound hexanal. Lipoxygenase extracted from mung bean catalyzed the oxidative reaction of linoleic acid, after which the intermediate hydroperoxide compound was split via green bell pepper hydroperoxide lyase to produce hexanal. In ...

The stability and eventual interconversion of nine mono-glutamate folates (5-methyl-tetrahydrofolate, tetrahydrofolate, 5-formyltetrahydrofolate, 5,10-methenyltetrahydrofolate, 5,10-methylenetetrahydrofolate, dihydrofolate, 10-formylfolic acid, 10-formyltetrahydrofolate and folic acid) during the typical sample preparation steps (heat treatment for 10 min at 100 degrees C and incubation for 2 h at 37 degrees C) at different pH values have ...

The DV (digestive vacuole) of the malaria parasite, Plasmodium falciparum, is the site of Hb (haemoglobin) digestion and haem detoxification and, as a consequence, the site of action of CQ (chloroquine) and related antimalarials. However, the precise pH of the DV and the endocytic vesicles that feed it has proved ...

An indirect CE method was developed for the study of low-molecular weight organic acids (LMWOAs) in maize under the stress of cadmium. The influences of indirect reagents (phthalate, salicylic acid, and benzoic acid), coion concentration, and pH were studied. A buffer composed of 15 mmol/L benzoate and 0.2 mmol/L CTAB ...

The (GA)(n) microsatellite has been known from previous studies to adopt unusual, ordered, cooperatively melting secondary structures in neutral aqueous solutions containing physiological concentrations of salts, at acid pH values or in aqueous ethanol solutions. To find more about the primary structure specificity of these structures, we performed parallel comparative ...

Electron microscopy of lignocellulosic biomass following high-temperature pretreatment revealed the presence of spherical formations on the surface of the residual biomass. The hypothesis that these droplet formations are composed of lignins and possible lignin carbohydrate complexes is being explored. Experiments were conducted to better understand the formation of these "lignin" ...

The second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) releases Ca(2+) from the acidic Ca(2+) stores of many organisms, including those of the sea urchin egg. We investigated whether the pH within the lumen of these acidic organelles changes in response to stimuli. Fertilization activates the egg by Ca(2+) release ...

The kinetics and mechanisms of the reaction of cysteine with cysteine thiosulfinate ester in aqueous solution have been studied by stopped-flow spectrophotometry between pH 6 and 14. Two reaction pathways were observed for pH > 12: (1) an essentially pH-independent nucleophilic attack of cysteinate on cysteine thiosulfinate ester, and (2) ...

The majority of published studies on the adaptive heat or acid tolerance response of Listeria monocytogenes have been performed with a single strain exposed to a single adaptation treatment; however, in food ecosystems, microorganisms commonly exist as multi-species communities and encounter multiple stresses, which may result in "stress hardening". Therefore, ...

Crude 2,6-naphthalene dicarboxylic acid was purified by Pseudomonas sp. HN-72 which biotransformed the major impurity of 2-formyl-6-naphthoic acid into 2,6-naphthalene dicarboxylic acid. The biotransformation yield reached 100% when the reaction was performed at 40 degrees C for 1 h, in 200 ml KH(2)PO(4)/KOH buffer (50 mM, pH 8.0), with 0.2% ...

In selenocysteine (Sec, U)-containing proteins the selenenylsulfide bridge and its reduced thiol-selenol counterpart are usually the significant species. An important role for serine as flanking amino acid in the redox potential of S-S and S-Se bridges was proposed for some thioredoxin reductases. To check the generality of this proposal, model ...

The aim of the present study was to identify a medicine which strongly enhanced the bitterness of clarithromycin dry syrup (CAMD) when administered concomitantly and to develop a method to suppress this enhanced bitterness. The bitterness enhancement was evaluated not only by gustatory sensation tests but also using pH and ...

Effective electrophoretic mobility data of 20 amino acids reported in the literature are analyzed and interpreted through simple physicochemical models, which are able to provide estimates of coupled quantities like hydrodynamic shape factor, equivalent hydrodynamic radius (size), net charge, actual pK values of ionizing groups, partial charges of ionizing groups, ...

AIMS: To estimate the effect of pH on the structures of bacterial community during fermentation of vegetable wastes and to investigate the relationship between bacterial community dynamics and product distribution. METHODS AND RESULTS: The bacterial communities in five batch tests controlled at different pH values [uncontrolled (about pH 4), 5, ...

Glycolic acid (GA) and other alpha-hydroxyacids (AHAs) are common ingredients of products designed to accelerate exfoliation of the skin. It is known that acidic pHs are essential in order to increase the efficacy of AHA-based products. The formulator is, therefore, obliged to achieve a difficult balance between performance (skin exfoliation) ...

Physiological and behavioural responses of the acid-sensitive amphipod Gammarus pulex exposed to a wide range of acid conditions (pH 4.1, 5.1, 6.0) under laboratory conditions were investigated. An exposure of 38 h to acid conditions caused significant decreases in survival rate, osmolality, haemolymph Na+ concentration, ventilatory and locomotor activity compared ...

The lipF gene of Mycobacterium tuberculosis has been implicated in pathogenesis and its promoter has been shown to be upregulated by acidic stress. To further define the acidic pH that upregulates the lipF promoter from M. tuberculosis and to establish that it is specifically upregulated by acid stress and not ...

Folic acid (FA) is used, in many countries, in nutritional supplements or for the fortification of cereals and their products. It is also used in vitamin pills. Recently, it was reported that folates may act as antioxidants; therefore, in the present study, the effect of pH of the surrounding medium ...

A series of experiments was performed to prepare acidic macroencapsulated buffers composed of 20% Ca(H2PO4)(2) and 80% Eudragit S 100 polymer and alkaline macrocapsules composed of 65% K2HPO4 and 35% Eudragit E PO polymer (the powdered form of Eudragit E 100). Eudragit S 100 was shown to be soluble at ...

Wine is a complex solution containing several components with several likely antimicrobial properties. Low pH (3.0 to 4.0), high organic acid content (titratable acidity > or = 6.0 g/L tartaric acid), relatively high ethanol (10% to 15%), and potentially high total sulfur dioxide (0 to 300 ppm) may contribute to ...

BACKGROUND: We have shown previously that abdominal insufflation with CO(2) increases serum levels of IL-10 and TNFalpha and increases survival among animals with lipopolysaccharide (LPS)-induced sepsis, even after a laparotomy. We demonstrated previously that the effect of CO(2) is not from changes in systemic pH, although the peritoneum is locally ...

Survival of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes was evaluated in cranberry juice concentrates to determine if a 5-log reduction could be achieved without any other treatment. Inactivation at 0 degrees C in concentrates with different oBrix levels was determined for a five-strain composite of the individual pathogens in ...

Bifidobacteria are one of the main microbial inhabitants of the human colon. Usually administered in fermented dairy products as beneficial microorganisms, they have to overcome the acidic pH found in the stomach during the gastrointestinal transit to be able to colonize the lower parts of the intestine. The mechanisms underlying ...

Humic substances and clay minerals have been studied extensively in radioactive waste management. In our research, the sorption and desorption of radiocobalt on montmorillonite in the presence and absence of fulvic acid as a function of pH and ionic strength were investigated under ambient conditions by using batch techniques. The ...

The effects of pH on the performance of anoxic sulfide oxidizing (ASO) reactor were evaluated. Performance was investigated under various operational conditions at influent pH range of 4-11. At the influent pH of 7-7.5 during loading tests and HRT tests, the sulfide oxidation was partial. In general, the amount of ...

Communities and ecosystems are connected through exchange of individuals and material. After an environmental stressor disrupts the community structure of an ecosystem, this connectedness has the potential to rehabilitate a community. Dispersing individuals could fill open niches created due to the environmental stressor and bring a community back to its ...

The role of n-octanol as mobile phase additive for the lipophilicity assessment of 45 structurally diverse acidic drugs both at neutral (pH 2.5) and ionized form (pH 7.4) was investigated. Extrapolated retention factors logk(w) were determined on a BDS C18 column using methanol as organic modifier and different amounts of ...

Hydrolysis of fenoxaprop-p-ethyl (FE), a widely used herbicide, was studied in aqueous buffer solutions at pH ranging from 4.0 to 10.0. The degradation kinetics, strongly dependent on pH values, followed first-order kinetics. FE was relatively stable in neutral media, whereas it degraded rapidly with decreasing or increasing pH. In acidic ...