Fall In pH Research Articles

MEAT QUALITY OF LOCAL AND HYBRID RABBITS

pH, colour and oxidative status were evaluated to study the effect of rabbit genotype on meat quality. Commercial Hybrids, selected for high growth rate and a local population, characterized by slow growing, were used. Meat quality characteristics of L. lumborum and B. femoris muscles showed significant differences between genotypes. Local population had higher pHu values but lower pH fall values than Hybrids. Hybrids showed higher lightness values and TBARS contents than local population. Meat quality parameters were influenced by genotype. The differences between genotypes could be related to the different degree of maturity because the rabbits, in relation to the different growth rate, were slaughtered at the same weight but at different age.

MEAT QUALITY OF LOCAL AND HYBRID RABBITS

pH, colour and oxidative status were evaluated to study the effect of rabbit genotype on meat quality. Commercial Hybrids, selected for high growth rate and a local population, characterized by slow growing, were used. Meat quality characteristics of L. lumborum and B. femoris muscles showed significant differences between genotypes. Local population had higher pHu values but lower pH fall values than Hybrids. Hybrids showed higher lightness values and TBARS contents than local population. Meat quality parameters were influenced by genotype. The differences between genotypes could be related to the different degree of maturity because the rabbits, in relation to the different growth rate, were slaughtered at the same weight but at different age.

Acidogenic potential of soy and bovine milk beverages

Soy beverages are water extracts of whole soybeans and are often promoted as a healthy alternative to bovine milk. Little analysis has been carried out to determine the effects of soy beverages on oral health, especially their potential acidogenicity. ObjectivesThe aim of this study was to determine the potential acidogenicity of a range of soy and bovine milk beverages. MethodsIn vitro acid production by Streptococcus mutans was measured in soy and milk beverages at a constant pH of 6.5 or 5.5, as was the fall in pH over a 10min period. The acid buffering capacity and calcium and phosphate concentrations (total and soluble) of the beverages were also determined. ResultsThe rate of acid production by S. mutans in the milk beverages was five to six times lower at pH 6.5 than in the soy beverages and three to five times lower at pH 5.5. Whilst the pH fall in the presence of S. mutans over 10min was negligible in the milk beverages there was a significant decrease in pH in the soy beverages. This was also reflected in the lower buffering capacity of the soy beverages. The levels of soluble calcium in the soy beverages were lower than those in the milk beverages although total calcium contents were similar. ConclusionsSoy beverages have a higher potential acidogenicity than bovine milk beverages. Clinical significance statementPatients consider soy beverages to be a healthy, low cariogenic alternative to other beverages, including bovine milk. This study shows that soy beverages have a higher potential acidogenicity than bovine milk and therefore may have a greater potential cariogenicity.

Potential microbial candidate strains for management of nutrient requirements of crops

Zinc (Zn) and phosphorus (Pi) are essential for optimum plant growth. Upon application, they get fixed in the soil matrix. Application of more than one microbe for each nutrient is often difficult. Azotobacter (31), Azospirillum (38), Bacillus (19) and Pseudomonas (82) strains were isolated from diverse crop production systems and were evaluated for solubilization of ‘Zn’ and ‘Pi’ in vitro from insoluble zinc (ZnO, ZnCO3) and phosphorus [tricalcium phosphate (TCP)], respectively. After 15 days of incubation, 15 strains solubilized zinc and produced >50 cm2 solubilization zone on solid media. In broth culture, with ZnO as zinc source, B116 could release maximum available Zn (13.12 ppm) and with ZnCO3, B118 could release highest available Zn (16.3 ppm). Pseudomonas strain PIII-105 released highest available 'Pi' (14.8 ppm) and solubilization of Zn and Pi corresponded with fall in pH of the medium except in case of B116. Two (2) strains of Azospirillum, 6 strains each of Bacillus and Pseudomonas showed a clearance zone area of >50 cm2with both Zn sources. Similarly, 2 strains each of Azospirillum and Bacillus and 3 strains of Pseudomonas solubilized TCP. Azospirillum strains As-20, As-22; Bacillus strains B113, B118; and Pseudomonas strains P17, P33 and PIII 105 solubilized both Zn and P sources showing their ability to supplement both essential nutrients to plants. Interestingly,Azospirillum is already known to supplement nitrogen also. Key words: Multi-nutrient management, zinc carbonate, zinc oxide, tricalcium phosphate,Pseudomonas, Bacillus, Azospirillum.

Mathematical modeling of the role of carbonic anhydrase II and IV on the influx of CO2 in a Xenopus oocyte

Exposing oocytes to a solution containing CO2/HCO3 causes the familiar fall in intracellular pH (pHi) and a rise in surface pH (pHS) followed by a decay. Musa‐Aziz et al (ASN, 2005) examined the effects of carbonic anhydrases (CAs) on pH transients caused by CO2 influx. They found that injecting CAII into oocytes or expressing CAIV on the oocyte surface accelerates the initial rate of pHi acidification (dpHi/dt) and amplifies the height of the pHS spike (ΔpHS). They proposed that both enzymes enhance CO2 influx by maximizing CO2 gradients across the plasma membrane. We use a mathematical model of a Xenopus oocyte—which accounts for CO2, carbonic acid (H2CO3), HCO3, protons, and a multitude of non‐HCO3 buffer pairs—to investigate the above findings. We simulate the experimental protocol in which the CO2/HCO3 solution is delivered from the bulk to the oocyte surface by raising exponentially the concentrations of CO2, H2CO3 and HCO3 in the bulk and assuming that initially no CO2, H2CO3 and HCO3 are present in the extracellular unconvected fluid. We use the experimental data for 1.5% CO2/10mM HCO3 (pHo=7.5) to find parameter values that simultaneously match ΔpHS, the time that it takes for pHS to reach its peak (tP), dpHi/dt, and the time delay in the pHi decay. We validate the model against data collected when exposing oocytes to 5% CO2/33mM HCO3 and to 10% CO2/66mM HCO3. The model confirms that CAII and CAIV enhance CO2 influx.

Repeated short‐term warming of red blood cell concentrates has minimal effect on their quality

Blood components must be stored under controlled temperature conditions, for reasons of component quality and safety. However, there are occasions when components may be exposed to conditions outwith the defined limits. This study aimed to generate prospective data on the effect of red cell exposure to extremes of temperature. Study 1: red cell concentrates (RCC) in saline, adenine, glucose and mannitol (SAGM), made after ambient overnight hold of whole blood, were exposed to either +22°C or -2°C for up to three periods of 3 h on days 3, 8 and 15 of storage, followed by a 5 h exposure on day 29. Study 2: RCC in SAGM were exposed to 25°C for 24 or 48 h from day 2. In vitro markers of cell quality were measured during storage to 43 days, and compared with control units that had been stored at 2-6°C. Multiple short-term exposures to +22°C or -2°C did not cause any significant changes to pH, haemolysis, supernatant potassium, cellular ATP, 2,3-DPG, or deformability, when compared to control units. Exposure of RCC to 25°C for 24 or 48 h caused a significant fall in pH, ATP, and deformability. Red cells may be damaged by prolonged exposure to warm temperatures, but repeated short-term exposure to 22°C or -2°C does not appear to affect the in vitro quality of RCC. It is important to note that no bacterial growth studies were performed during this study.

Effect of Herbal Formulation AV/DAC-16 Supplementation on Rumen Profiles in Buffalo Calves (Bubalus bubalis)

12 healthy buffalo calves with BW range 100-150 kg were fistulated and divided into two groups of 6 animals each. Control group animals were fed on conventional diet comprising of wheat straw (2 kg), green fodder (8 kg), concentrate (1.0 kg) and mineral mixture (0.050kg). The animals of the treatment group were kept on diet similar to the control group along with feeding of herbally formulated drug AV/DAC-16@ 15 gm/day for 21 days. Each animal was sampled for three consecutive days at 0 hr i.e., immediately before feeding and subsequent samples were taken at 2, 4 and 6 h intervals after feeding. There was a significant fall in pH at 2 and 4 h post-prandial and in MBRT during the entire observation period. TVFA concentration increased significantly in the treatment group. Though oral administration of AV/DAC-16 did not have any prominent effect on the protozoal count, the bacterial count increased significantly in comparison to control group. Total nitrogen concentrations fell significantly while a significant increase was observed in the ammonia nitrogen content in the supplemented group at 6 hours after feeding. The animals of supplemented group showed a significant increase in body weights.

Breathing 40% O2can attenuate postcontraction hyperaemia or muscle fatigue caused by static forearm contraction, depending on timing

Little is known of the role of O(2)-dependent mechanisms in the hyperaemia associated with static muscle contraction or recovery from fatigue. Thus, in recreationally active, young, male subjects, forearm contraction was performed twice at 100% maximal voluntary effort until exhaustion, with a 7 min recovery period, whilst 40% O(2) (hyperoxia) was breathed during the contractions only, or during recovery only, or room air (normoxia) was breathed throughout. When hyperoxia was limited to the contractions, postcontraction increases in forearm blood flow, measured by venous occlusion plethysmography, were ∼25% lower (P < 0.05, n = 10) than during normoxia throughout. Furthermore, the postcontraction increase in venous lactate and fall in pH were attenuated (P < 0.05, n = 8). However, there was no effect on fatigue; time to voluntary exhaustion of contraction 2 was ∼25% less than for contraction 1 in both conditions. By contrast, when hyperoxia was limited to recovery (n = 10), there was no effect on postcontraction increases in forearm blood flow, but fatigue was ameliorated; time to voluntary exhaustion of contraction 2 was comparable to that of contraction 1. These results allow the novel conclusions that, even during static forearm contraction at 100% maximal voluntary effort, additional O(2) dissolved in plasma can attenuate the contribution made by O(2)-dependent dilator substances to postcontraction hyperaemia and that these substances may be released from the muscle fibres or blood vessel wall. Furthermore, they indicate that even in recreationally active individuals, recovery from fatigue can be improved by additional O(2) made available during recovery, and the O(2)-dependent mechanisms that contribute to fatigue are different from those that induce postcontraction hyperaemia.

Storage of platelets: effects associated with high platelet content in platelet storage containers.

A major problem associated with platelet storage containers is that some platelet units show a dramatic fall in pH, especially above certain platelet contents. The aim of this study was a detailed investigation of the different in vitro effects occurring when the maximum storage capacity of a platelet container is exceeded as compared to normal storage. Buffy coats were combined in large-volume containers to create primary pools to be split into two equal aliquots for the preparation of platelets (450-520×10(9) platelets/unit) in SSP+ for 7-day storage in two containers (test and reference) with different platelet storage capacity (n=8). Exceeding the maximum storage capacity of the test platelet storage container resulted in immediate negative effects on platelet metabolism and energy supply, but also delayed effects on platelet function, activation and disintegration. Our study gives a very clear indication of the effects in different phases associated with exceeding the maximum storage capacity of platelet containers but throw little additional light on the mechanism initiating those negative effects. The problem appears to be complex and further studies in different media using different storage containers will be needed to understand the mechanisms involved.

Fortification and fermentation of fruit juices with probiotic lactobacilli

In present investigation, two Lactobacillus isolates, viz. L. plantarum and L. acidophilus, were observed to be able not only to survive but to utilize fruit juices for their cell synthesis, as indicated by a decrease in fruit sugar and pH, and increase in acidity. L. acidophilus was found to consume the sugar at a faster rate than L. plantarum, although the fall in sugar and pH and increase in acidity was faster during the first 24 h and became a little slower during the next 48 h, which could be due to the accumulation of too much acid during the initial 24 h of fermentation. Still, both cultures were found to be able to survive in fermented juices with high acidity and low pH. Therefore, it could be concluded that such probiotic-fortified fruit juices could certainly be exploited as a medium for the delivery of probiotics, and could be used as a functional healthy beverage to promote better health and nutrition of the population, especially for those who are allergic or intolerant to milk-based products.

Effect of chewing paneer and cheese on salivary acidogenicity: a comparative study.

ABSTRACTAim: The aim was to evaluate the salivary pH reversal phenomenon by chewing paneer and processed cheese after a chocolate challenge.Materials and methods: Thirty caries-free children were randomly selected and divided into 2 groups: Control group was given processed cheese (Amul) and the experimental group was given paneer (Amul) after a chocolate challenge. After determining the resting salivary pH using GC pH strips, the subjects were asked to eat the test foods and salivary pH was measured at time intervals of 5, 10, 15, 30 and 60 minutes to record the time taken for the salivary pH to return to baseline values after an acidogenic challenge.Results: The data was analyzed and intergroup comparison was done using paired student’s t-test. The test meals increased salivary pH after chocolate challenge significantly from baseline values and neutralized the fall in pH after a chocolate challenge. The protective effect was evident after 5 minutes of consuming chocolate and was highest up to 30 minutes after which the salivary pH gradually fell but had not returned to baseline values even at 60 minutes.Conclusion: The findings suggest that chewing of paneer like cheese abolishes the fall in salivary pH caused by sugar consumption and maybe recommended as a protective food in pediatric diet counseling.How to cite this article: Tayab T, Rai K, Kumari V, Thomas E. Effect of Chewing Paneer and Cheese on Salivary Acidogenicity: A Comparative Study. Int J Clin Pediatr Dent 2012;5(1):20-24.

Modulation of ion transport across rat distal colon by cysteine

The aim of this study was to identify the actions of stimulation of endogenous production of H2S by cysteine, the substrate for the two H2S-producing enzymes, cystathionine-β-synthase and cystathionine-γ-lyase, on ion transport across rat distal colon. Changes in short-circuit current (Isc) induced by cysteine were measured in Ussing chambers. Free cysteine caused a concentration-dependent, transient fall in Isc, which was sensitive to amino-oxyacetate and β-cyano-L-alanine, i.e., inhibitors of H2S-producing enzymes. In contrast, Na cysteinate evoked a biphasic change in Isc, i.e., an initial fall followed by a secondary increase, which was also reduced by these enzyme inhibitors. All responses were dependent on the presence of Cl− and inhibited by bumetanide, suggesting that free cysteine induces an inhibition of transcellular Cl− secretion, whereas Na cysteinate – after a transient inhibitory phase – activates anion secretion. The assumed reason for this discrepancy is a fall in the cytosolic pH induced by free cysteine, but not by Na cysteinate, as observed in isolated colonic crypts loaded with the pH-sensitive dye, BCECF. Intracellular acidification is known to inhibit epithelial K+ channels. Indeed, after preinhibition of basolateral K+ channels with tetrapentylammonium or Ba2+, the negative Isc induced by free cysteine was reduced significantly. In consequence, stimulation of endogenous H2S production by Na cysteinate causes, after a short inhibitory response, a delayed activation of anion secretion, which is missing in the case of free cysteine, probably due to the cytosolic acidification. In contrast, diallyl trisulfide, which is intracellularly converted to H2S, only evoked a monophasic increase in Isc without the initial fall observed with Na cysteinate. Consequently, time course and amount of produced H2S seem to strongly influence the functional response of the colonic epithelium evoked by this gasotransmitter.

The Estimation of Acidic Behavior of Wood by Treatment with Aqueous Solution

As a new approach, the acidity that wood exhibits under moderate conditions is assayed by stimulated dissociation of weak wood acids in lightly basic secondary phosphate solutions. To assure a sufficient dissociation of hardly soluble weak acids in the solution, the amount of wood suspended in Na2HPO4 solutions should be small but vary depending on the degree of acidity of wood species. However, the difficulties are associated with the titration of very dilute acids limiting the precision of the measurement. If the disintegrated wood is suspended in a secondary phosphate solution, the weak woods acids form the conjugate acid Na2HPO4 from secondary phosphate Na2HPO4 resulting in a pH fall of the solution. The decrease in the pH value in phosphate solution, which depends on the wood acidity, can be evaluated to estimate the acidity arising from wood under moderate conditions.

Effects of a coating resin containing S-PRG filler to prevent demineralization of root surfaces

The purpose of this study was to evaluate the ability of a coating material containing the surface pre-reacted glass-ionomer (S-PRG) filler to protect the root from demineralization in vitro. The proprietary coating resin containing the S-PRG filler (PRG Barrier Coat) was applied to human root dentin and immersed in acid buffer at pH 4.5 for 3 d. Demineralization was evaluated by micro-CT scanning and the dentin-material interface observed by scanning electron microscopy. The ability of the coating resin to modify acid production by Streptococcus mutans was investigated by monitoring pH using an ion-sensitive field-effect transistor pH electrode. Application of PRG Barrier Coat produced a coating layer with the thickness of approximately 200 µm and completely inhibited demineralization. The bacteria-induced pH fall at the material surface was significantly inhibited. We conclude that S-PRG fillercontaining coating resin may be an effective material for protecting exposed root from both chemical and biological challenges.

PH Buffering Does not Influence BDNF Responses to Exercise

The influence of acidosis on brain-derived neurotrophic factor (BDNF) was examined by buffering pH changes during 10 min of continuous low intensity (LIE) and following high intensity cycling exercise to exhaustion (HIE). 11 athletes participated in 2 trials separated by 1 week. Individuals received either a placebo infusion (isotonic saline) or an isotonic sodium bicarbonate infusion before and during exercise. Blood samples were drawn at rest, after LIE and after HIE, as well as 3, 6, 10 and 15 min post exercise. During placebo trial, HIE induced a profound decrease (p<0.01) of capillary blood bicarbonate concentration (HCO3-), pH, base excess (BE) and pCO2. Higher (p<0.01) HCO3-, pH and BE were found during bicarbonate infusion and post exercise in comparison to the placebo trial. Exercise induced an identical increase of blood lactate concentration in both trials. Serum BDNF concentration was increased (p<0.01) at the end of HIE and remained elevated until 3 min post exercise in both trials. The present study suggests that during HIE lactate might have an acidosis-independed impact on BDNF secretion because buffering of blood gases, that attenuate the fall of pH but not the accumulation of lactic acid, failed to alter the exercise-induced increase of BDNF.

Effects of Medium‐Voltage Electrical Stimulation on Postmortem Changes in Fat‐Tailed Sheep

Effects of different medium-voltage electrical stimulation (ES) and ageing on postmortem changes in longissimus dorsi muscle of the fat-tailed sheep were studied. Fifteen male animals were divided into 5 equal groups (n= 3) including: T₁ (control, without ES), T₂ (100 V/30 s), T₃ (100 V/60 s), T₄ (150 V/30 s), and T₅ (150 V/60 s) with fixed frequency of 50 Hz. Five minutes after sticking, the carcasses were stimulated in order of the treatments. After normal processing, they were kept at 6 °C for 14 d. ES accelerated the glycolytic rate resulting in a significant fast fall in pH (P < 0.05) during the 1st 6-h postmortem (PM) with a gradual decline until 24-h PM, and a simultaneous significant reduction in adenosine triphosphate (ATP) content (P < 0.05). There was a significant (P < 0.05) decline in the total calpain activity during the 1st 6-h PM. The muscles from ES carcasses had significantly (P < 0.05) lower water holding capacity (WHC) than those from nonstimulated ones. Ageing revealed a significant (P < 0.05) effect on the reduction of WHC. No significant difference was found for the mean value of the muscle color (L*, a*, and b*) in all treatment groups during ageing (P > 0.05). The results of free amino acid (FAA) content and myofibrillar fragmentation index (MFI) revealed a significant improvement of proteolysis and tenderness by ES and ageing (P < 0.05). In the present study, higher voltage/duration (150 V/60 s) showed greater effects and significantly accelerated glycolysis, pH decline, and ATP depletion and thus decreased the time for rigor completion and improved the tenderness.

Semi-quantitative Prediction of the Corrosion Risk of Steel in Concrete Using XRD Analysis

The present study concerns a technique for determining the chloride binding capacity, using the XRD curve containing the peaks for Friedel' s salt. The influence of chloride binding on the corrosion behaviour was also evaluated. The binding capacity of chloride ions in cement paste was determined by the water extraction method. As a result, it was found that the chloride binding capacity is strongly dependent on the W/C, binder type, curing age and total chloride concentration in the paste. It is notable that chloride binding has a crucial influence on corrosion propagation: an increase in the binding capacity resulted in a decrease in the corrosion rate at a given chloride concentration in mortar specimens. However, the impact of chloride binding on the onset of corrosion was marginal, presumably due to a release of bound chlorides into free chlorides at the stage of corrosion, accompanying a pH fall in the vicinity of the steel. A strong relation between the peak intensity for Friedel' s salt and the concentration of bound chloride was observed, which can be used to determine the bound chlorides and thus the risk of chloride-induced corrosion of steel in concrete.

Gastric Infection by Helicobacter pylori

Helicobacter pylori infects half of the world's population and plays a causal role in ulcer disease and gastric cancer. This pathogenic neutralophile uniquely colonizes the acidic gastric milieu through the process of acid acclimation. Acid acclimation is the ability of the organism to maintain periplasmic pH near neutrality in an acidic environment to prevent a fall in cytoplasmic pH in order to maintain viability and growth in acid. Recently, due to an increase in antibiotic resistance, the rate of H. pylori eradication has fallen below 80% generating renewed interest in novel eradication regimens and targets. In this article, we review the gastric biology of H. pylori and acid acclimation, various detection procedures, antibiotic resistance and the role that gastric acidity plays in the susceptibility of the organism to antibiotics currently in use and propose several novel drug targets that would promote eradication in the absence of antibiotics.

Evaluation of pH at the Bacteria–Dental Cement Interface

Physiochemical assessment of the parasite-biomaterial interface is essential in the development of new biomaterials. The purpose of this study was to develop a method to evaluate pH at the bacteria-dental cement interface and to demonstrate physiochemical interaction at the interface. The experimental apparatus with a well (4.0 mm in diameter and 2.0 mm deep) was made of polymethyl methacrylate with dental cement or polymethyl methacrylate (control) at the bottom. Three representative dental cements (glass-ionomer, zinc phosphate, and zinc oxide-eugenol cements) were used. Each specimen was immersed in 2 mM potassium phosphate buffer for 10 min, 24 hrs, 1 wk, or 4 wks. The well was packed with Streptococcus mutans NCTC 10449, and a miniature pH electrode was placed at the interface between bacterial cells and dental cement. The pH was monitored after the addition of 1% glucose, and the fluoride contained in the cells was quantified. Glass-ionomer cement inhibited the bacteria-induced pH fall significantly compared with polymethyl methacrylate (control) at the interface (10 min, 5.16 ± 0.19 vs. 4.50 ± 0.07; 24 hrs, 5.20 ± 0.07 vs. 4.59 ± 0.11; 1 wk, 5.34 ± 0.14 vs. 4.57 ± 0.11; and 4 wks, 4.95 ± 0.27 vs. 4.40 ± 0.14), probably due to the fluoride released from the cement. This method could be useful for the assessment of pH at the parasite-biomaterial interface.

A comparison of reverse osmosis, nanofiltration and ultrafiltration as concentration processes for skim milk prior to drying

Skim milk was concentrated by reverse osmosis (RO), nanofiltration (NF) and ultrafiltration (UF) and the retentates were spray-dried. The resulting powders were reconstituted to 25% TS and sterilised to evaluate their heat stability. Reverse osmosis led to maximum retention of calcium, a fall in pH for its retentate and its reconstituted powder. All RO powders produced a weak gel on heating. Some calcium was lost during NF and a greater amount during UF. Their resulting reconstituted powders had a higher pH than those produced by RO. Powders produced by UF showed poor heat stability. Only one powder produced by NF showed good heat stability. This could be improved by addition of stabilisers at appropriate addition rates.