Effect of diet phase change, dietary Ca and P level and phytase on bird performance and real-time gizzard pH measurements.

PubMed

Lee, S A; Dunne, J; Mottram, T; Bedford, M R

2017-06-01

In this study, a novel capsule technique was used to capture real-time pH readings from the gizzard over several hours, in response to different dietary treatments. 1. The first experiment was a preliminary study into capsule administration and pH recordings using 9 male Ross 308 broilers from 20 d. In the second experiment, broilers (576) were fed in two phases (0-21 and 21-42 d) with 4 treatment groups; low and adequate Ca and AvP diets with and without Quantum Blue phytase (1500 FTU/kg). Capsules were administered to 8 birds from each treatment group, pre and post diet phase change, with readings captured over a 2.5 h period. 2. Phytase addition improved body weight gain (BWG) and feed conversion ratio (FCR) of birds fed low dietary Ca, while having no significant effect on birds fed adequate Ca diets. Unexpectantly, diets with higher Ca levels gave a lower average gizzard pH compared to the low Ca diet. Phytase addition, irrespective of Ca level, increased average gizzard pH. Fluctuations in gizzard pH (0.6-3.8) were observed across all treatment groups. Higher frequencies of pH readings below pH 1.0 were seen in birds fed an adequate Ca diet and with phytase supplementation of a low Ca diet. 3. These results signify the potential use of capsule techniques to monitor real-time pH changes. The implication on gastric protein and fibre hydrolysis as a result of large fluctuations in pH should be considered.

Modelling Research: A Collaborative Approach to Helping PhD Students Develop Higher-Level Research Skills

ERIC Educational Resources Information Center

Garcia-Perez, Alexeis; Ayres, Robert

2012-01-01

A high proportion of PhD candidates in science and engineering fail to complete their degrees. This paper reports the results of a series of workshops where experienced researchers and supervisors were brought together with PhD students to discuss and develop a model of the PhD process. The objective was to help students develop a more rounded and…

Neutralizing salivary pH by mouthwashes after an acidic challenge.

PubMed

Dehghan, Mojdeh; Tantbirojn, Daranee; Kymer-Davis, Emily; Stewart, Colette W; Zhang, Yanhui H; Versluis, Antheunis; Garcia-Godoy, Franklin

2017-05-01

The aim of the present study was to test the neutralizing effect of mouthwashes on salivary pH after an acidic challenge. Twelve participants were recruited for three visits, one morning per week. Resting saliva was collected at baseline and after 2-min swishing with 20 mL orange juice as an acidic challenge. Participants then rinsed their mouth for 30 s with 20 mL water (control), an over-the-counter mouthwash (Listerine), or a two-step mouthwash, randomly assigned for each visit. Saliva was collected immediately, 15, and 45 min after rinsing. The pH values of the collected saliva were measured and analyzed with anova, followed by Student-Newman-Keuls post-hoc test (significance level: 0.05). Orange juice significantly lowered salivary pH. Immediately after rinsing, Listerine and water brought pH back to baseline values, with the pH significantly higher in the Listerine group. The two-step mouthwash raised pH significantly higher than Listerine and water, and higher than the baseline value. Salivary pH returned to baseline and was not significantly different among groups at 15 and 45 min post-rinsing. Mouth rinsing after an acidic challenge increased salivary pH. The tested mouthwashes raised pH higher than water. Mouthwashes with a neutralizing effect can potentially reduce tooth erosion from acid exposure. © 2015 Wiley Publishing Asia Pty Ltd.

The effects of intermittent exposure to low pH and oxygen conditions on survival and growth of juvenile red abalone

NASA Astrophysics Data System (ADS)

Kim, T. W.; Barry, J. P.; Micheli, F.

2013-02-01

Exposure of nearshore animals to hypoxic, low pH waters upwelled from below the continental shelf and advected near the coast may be stressful to marine organisms and lead to impaired physiological performance. We mimicked upwelling conditions in the laboratory and tested the effect of fluctuating exposure to water with low pH and/or low oxygen levels on the mortality and growth of juvenile red abalone (Haliotis rufescens, shell length 5-10 mm). Mortality rates of juvenile abalone exposed to low pH (7.5, total scale) and low O2 (40% saturation, 5 mg L-1) conditions for periods of 3 to 6 h every 3-5 days over 2 weeks did not differ from those exposed to control conditions (O2: 100% saturation, 12 mg L-1; pH 8.0). However, when exposure was extended to 24 h repeated twice over a 15 day period, juveniles experienced higher mortality in the low oxygen treatments compared to control conditions, regardless of pH levels (pH 7.5 vs. 8.0). Growth rates were reduced significantly when juveniles were exposed to low pH or low oxygen treatments and the growth was lowest when low pH exposure was combined with low O2. Furthermore, individual variation of growth rate increased when they were exposed to low pH and low O2 conditions. These results indicate that prolonged exposure to low oxygen levels is detrimental for the survival of red abalone, whereas both pH and oxygen is a crucial factor for their growth. However, given the higher individual variation in growth rate, they may have an ability to adapt to extended exposure to upwelling conditions.

High serum uric acid level and low urine pH as predictors of metabolic syndrome: a retrospective cohort study in a Japanese urban population.

PubMed

Hara, Shigeko; Tsuji, Hiroshi; Ohmoto, Yuki; Amakawa, Kazuhisa; Hsieh, Shiun Dong; Arase, Yasuji; Nakajima, Hiromu

2012-02-01

The objective of this study was to evaluate whether hyperuricemia, acidic urine, or their combination predicts metabolic syndrome (MetS). In study 1, 69,094 subjects who received a general health checkup between 1985 and 2005 were included in a cross-sectional study of serum uric acid (SUA) and urine pH in relation to MetS. In study 2, the association of SUA and urine pH with MetS development over a 5-year period was evaluated in 5617 subjects with body mass index less than 25 kg/m(2) at the first examination. In study 1, higher SUA and lower urine pH were both positively correlated to MetS status (P < .001). The combination of high SUA and low urine pH was significantly associated with higher MetS prevalence compared with the combination of low SUA and high urine pH (odds ratio, 3.383; 95% confidence interval [CI], 3.034-3.784 in men; odds ratio, 4.000; 95% CI, 2.992-5.452 in women). In study 2, the top quartile of SUA levels was associated with higher MetS development compared with the bottom quartile during the 5-year period in men (hazard ratio [HR], 1.793; 95% CI, 1.084-2.966; P = .023). In women, the HR was 3.732 (95% CI, 0.391-35.62; P = .252) for the upper vs the lower half of SUA levels. For urine pH, the HR was 1.955 (95% CI, 1.089-3.509; P = .025) for the bottom vs the top quartile in men. A likelihood ratio test confirmed that high SUA and low urine pH act synergistically in the development of MetS. High SUA, low urine pH, and their combination are predictive risk factors for MetS development. Copyright © 2012 Elsevier Inc. All rights reserved.

Higher cation exchange capacity determined lower critical soil pH and higher Al concentration for soybean.

PubMed

Baquy, M Abdulaha-Al; Li, Jiu-Yu; Shi, Ren-Yong; Kamran, Muhammad Aqeel; Xu, Ren-Kou

2018-03-01

Low soil pH and aluminum (Al) toxicity induced by soil acidification are the main obstacles in many regions of the world for crop production. The purpose of this study was to reveal the mechanisms on how the properties of the soils derived from different parent materials play role on the determination of critical soil pH and Al concentration for soybean crops. A set of soybean pot experiment was executed in greenhouse with a soil pH gradient as treatment for each of four soils to fulfill the objectives of this study. The results indicated that plant growth parameters were affected adversely due to Al toxicity at low soil pH level in all soils. The critical soil pH varied with soil type and parent materials. They were 4.38, 4.63, 4.74, and 4.95 in the Alfisol derived from loss deposit, and the Ultisols derived from Quaternary red earth, granite, and Tertiary red sandstone, respectively. The critical soil exchangeable Al was 2.42, 1.82, 1.55, and 1.44 cmol c /kg for the corresponding soils. At 90% yield level, the critical Al saturation was 6.94, 10.36, 17.79, and 22.75% for the corresponding soils. The lower critical soil pH and Al saturation, and higher soil exchangeable Al were mainly due to greater soil CEC and exchangeable base cations. Therefore, we recommended that critical soil pH, soil exchangeable Al, and Al saturation should be considered during judicious liming approach for soybean production.

Time course of pH change in plant epidermis using microscopic pH imaging system

NASA Astrophysics Data System (ADS)

Dan, Risako; Shimizu, Megumi; Kazama, Haruko; Sakaue, Hirotaka

2010-11-01

We established a microscopic pH imaging system to track the time course of pH change in plant epidermis in vivo. In the previous research, we have found out that anthocyanin containing cells have higher pH. However, it was not clear whether the anthocyanin increased the pH or anthocyanin was synthesized result from the higher pH. Therefore, we further investigated the relationship between anthocyanin and pH change. To track the time course of pH change in plant epidermis, we established a system using luminescent imaging technique. We used HPTS (8-Hydroxypyrene-1,3,6-Trisulfonate) as pH indicator and applied excitation ratio imaging method. Luminescent image was converted to a pH distribution by obtained in vitro calibration using known pH solution. Cellular level observation was enabled by merging microscopic color picture of the same region to the pH change image. The established system was applied to epidermal cells of red-tip leaf lettuce, Lactuca Sativa L. and the time course was tracked in the growth process. We would discuss about the relationship between anthocyanin and pH change in plant epidermis.

Combined effects of fermentation temperature and pH on kinetic changes of chemical constituents of durian wine fermented with Saccharomyces cerevisiae.

PubMed

Lu, Yuyun; Voon, Marilyn Kai Wen; Huang, Dejian; Lee, Pin-Rou; Liu, Shao-Quan

2017-04-01

This study investigated the effects of temperature (20 and 30 °C) and pH (pH 3.1, 3.9) on kinetic changes of chemical constituents of the durian wine fermented with Saccharomyces cerevisiae. Temperature significantly affected growth of S. cerevisiae EC-1118 regardless of pH with a higher temperature leading to a faster cell death. The pH had a more significant effect on ethanol production than temperature with higher production at 20 °C (5.95%, v/v) and 30 °C (5.56%, v/v) at pH 3.9, relative to that at pH 3.1 (5.25 and 5.01%, v/v). However, relatively higher levels of isobutyl alcohol and isoamyl alcohol up to 64.52 ± 6.39 and 56.27 ± 3.00 mg/L, respectively, were produced at pH 3.1 than at pH 3.9 regardless of temperature. In contrast, production of esters was more affected by temperature than pH, where levels of ethyl esters (ethyl esters of octanoate, nonanoate, and decanoate) and acetate esters (ethyl acetate and isoamyl acetate) were significantly higher up to 2.13 ± 0.23 and 4.61 ± 0.22 mg/L, respectively, at 20 °C than at 30 °C. On the other hand, higher temperature improved the reduction of volatile sulfur compounds. This study illustrated that temperature control would be a more effective tool than pH in modulating the resulting aroma compound profile of durian wine.

Biochar alters microbial community and carbon sequestration potential across different soil pH.

PubMed

Sheng, Yaqi; Zhu, Lizhong

2018-05-01

Biochar application to soil has been proposed for soil carbon sequestration and global warming mitigation. While recent studies have demonstrated that soil pH was a main factor affecting soil microbial community and stability of biochar, little information is available for the microbiome across different soil pH and the subsequently CO 2 emission. To investigate soil microbial response and CO 2 emission of biochar across different pH levels, comparative incubation studies on CO 2 emission, degradation of biochar, and microbial communities in a ferralsol (pH5.19) and a phaeozems (pH7.81) with 4 biochar addition rates (0.5%, 1.0%, 2.0%, 5.0%) were conducted. Biochar induced higher CO 2 emission in acidic ferralsol, largely due to the higher biochar degradation, while the more drastic negative priming effect (PE) of SOC resulted in decreased total CO 2 emission in alkaline phaeozems. The higher bacteria diversity, especially the enrichment of copiotrophic bacteria such as Bacteroidetes, Gemmatimonadetes, and decrease of oligotrophic bacteria such as Acidobacteria, were responsible for the increased CO 2 emission and initial positive PE of SOC in ferralsol, whereas biochar did not change the relative abundances of most bacteria at phylum level in phaeozems. The relative abundances of other bacterial taxa (i.e. Actinobacteria, Anaerolineae) known to degrade aromatic compounds were also elevated in both soils. Soil pH was considered to be the dominant factor to affect CO 2 emission by increasing the bioavailability of organic carbon and abundance of copiotrophic bacteria after biochar addition in ferralsol. However, the decreased bioavailability of SOC via adsorption of biochar resulted in higher abundance of oligotrophic bacteria in phaeozems, leading to the decrease in CO 2 emission. Copyright © 2017. Published by Elsevier B.V.

Combined effects of ocean acidification and temperature on planula larvae of the moon jellyfish Aurelia coerulea.

PubMed

Dong, Zhijun; Sun, Tingting

2018-08-01

Rapidly rising levels of atmospheric CO 2 have caused two environmental stressors, ocean acidification and seawater temperature increases, which represent major abiotic threats to marine organisms. Here, we investigated for the first time the combined effects of ocean acidification and seawater temperature increases on the behavior, survival, and settlement of the planula larvae of Aurelia coerulea, which is considered a nuisance species around the world. Three pH levels (8.1, 7.7 and 7.3) and two temperature levels (24 °C and 27 °C) were used in the present study. There were no interactive effects of temperature and pH on the behavior, survival, and settlement of planula larvae of A. coerulea. We found that the swimming speed and mortality of the planula larvae of A. coerulea were significantly affected by temperature, and low pH significantly affected settlement. Planula larvae of A. coerulea from the elevated temperature treatment moved faster and showed higher mortality than those at the control temperature. The settlement rate of A. coerulea planulae was significantly higher at the pH level of 7.3 than at other pH levels. These results suggest that seawater temperature increase, rather than reduced pH, was the main stress factor affecting the survival of A. coerulea planulae. Overall, the planula larvae of the common jellyfish A. coerulea appeared to be resistant to ocean acidification, but may be negatively affected by future seawater temperature increases. Copyright © 2018 Elsevier Ltd. All rights reserved.

Role of kappa-casein in the association of denatured whey proteins with casein micelles in heated reconstituted skim milk.

PubMed

Anema, Skelte G

2007-05-02

Reconstituted skim milk at pH from 6.5 to 7.1 was unheated, preheated (68 degrees C/20 min), or heated at 90 degrees C for 20-30 min. On preheating, the size of the casein micelles decreased by about 5-20 nm, with a greater effect at higher pH. The casein micelle size of the heated milk at pH 6.5 increased by about 30 nm when compared to that of the unheated or preheated milk. As the pH was increased before heating, the particle size gradually decreased so that, at pH 7.1, the size was markedly smaller than that for the unheated milk and slightly smaller than that for the preheated milk. High levels (about 85%) of denatured whey protein associated with the casein micelles at pH 6.5, and this level decreased as the pH increased so that, at pH 7.1, low levels (about 15%) were associated with the micelles. Low levels of alphaS-casein and beta-casein were found in the serum regardless of the heat treatment or the pH of the milk. At pH 6.5, low levels (about 10%) of kappa-casein were also found in the milk serum. In the unheated milk, the level of serum kappa-casein increased slightly with increasing pH; in the heated samples, the level of serum kappa-casein increased markedly and linearly with increasing pH so that, at pH 7.1, about 70% of the kappa-casein was in the serum phase. The results of this study indicate that the pH dependence of the levels of serum phase kappa-casein may be responsible for the change in distribution of the whey proteins between the colloidal and serum phases. This is the first report to demonstrate significant levels of dissociation of kappa-casein from the micelles at pH between 6.5 and 6.7, although this dissociation phenomenon is well known on heating milk at high temperatures at pH above 6.7.

High fluoride and low pH level have been detected in popular flavoured beverages in Malaysia.

PubMed

Ha Rahim, Zubaidah; M Bakri, Marina; Hm, Zakir; Ia, Ahmed; Na, Zulkifli

2014-03-01

In children, excessive ingestion of fluoride from different sources including bottled drinking water and flavoured beverages or soft drinks can lead to the development of dental fluorosis. In addition, the pH level of beverages is important. Low pH can cause dental erosion. In this study we explore the fluoride content and pH level of certain popular beverages available in Malaysian supermarkets and hawkers' stalls. Bottled drinking water and selected popular flavoured packet drinks were purchased from a supermarket and the corresponding flavoured hawkers' drinks, from a hawker's stall in Kuala Lumpur. Fluoride and pH of the beverages were determined using digital fluoride meter and digital pH meter respectively. It was found that fluoride content and pH level vary among the beverages. The mean fluoride content in both packet and hawkers' drinks (7.64±1.88 mg/L, 7.51±1.60 mg/L, respectively) was approximately 7 times higher than the bottled drinking water (1.05±0.35 mg/L). Among the beverages, the tea packet drink was found to contain the highest amount of fluoride (13.02±0.23 mg/L). The mean pH of bottled-drinking water was near neutral (6.96±0.17), but acidic for both supermarket (4.78.00±0.49) and hawkers' drinks (5.73±0.24). The lychee packet drink had the lowest pH level (2.97±0.03). Due to the wide variation of the fluoride content and pH level of the drinks tested in this study, it is recommended that steps should be taken to control the fluoride concentration and pH level in beverages if dental fluorosis and erosion are to be prevented.

Relative significances of pH and substrate starch level to roles of Streptococcus bovis S1 in rumen acidosis.

PubMed

Chen, Lianmin; Liu, Shimin; Wang, Hongrong; Wang, Mengzhi; Yu, Lihuai

2016-12-01

To clarify the relative importance of pH and substrate starch level in fermentation characteristics and regulatory mechanism of Streptococcus bovis S1 in rumen acidosis, an in vitro fermentation of three levels of soluble starch (1, 3 and 9 g/L) was established with pH in the media were maintained constant at 5.5 or 6.5. The results showed that the dominant product of S. bovis S1 was lactate at both pH, the production depended on the starch level, and more lactate was produced at pH 6.5 than that at pH 5.5 (P < 0.001). At pH 5.5, the activity of lactate dehydrogenase (LDH) and α-amylase (α-AMY), their abundances, the relative expressions of LDH, PFL (gene encoding pyruvate formate-lyase), CCPA (gene encoding global catabolite control protein A) and α-AMY genes were higher than those at pH 6.5 (P < 0.05), whereas the concentration of fructose-1,6-diphosphate (FDP) was lower. The activity of LDH, α-AMY and FDP, and the relative expressions of LDH, PFL, CCPA and α-AMY genes were, in general, positively related to the starch level. The canonical regression analysis indicated that the pH had more profound effect compared with the starch level, in terms of the acid productions, enzyme activity and gene expressions. It was concluded that the fermentation of S. bovis was regulated at the transcription level in response to both pH and substrate starch concentration, but more sensitive to pH changes.

An Exploratory Investigation of the Research Self-Efficacy, Interest in Research, and Research Knowledge of Ph.D. in Education Students

ERIC Educational Resources Information Center

Lambie, Glenn W.; Hayes, B. Grant; Griffith, Catherine; Limberg, Dodie; Mullen, Patrick R.

2014-01-01

Faculty members in higher education are called to be effective researchers; however, there is limited research examining the research development of Ph.D. students. The cross-sectional, correlational investigation we report here examined levels of research self-efficacy, interest in research, and research knowledge of Ph.D. in education students…

Saliva pH as a biomarker of exam stress and a predictor of exam performance.

PubMed

Cohen, Miri; Khalaila, Rabia

2014-11-01

Salivary pH is regulated by the sympathetic and parasympathetic nervous system; therefore, it may serve as a biomarker of stress. To assess the associations between the cognitive and emotional dimensions of exam stress and pH levels, and the predictability of salivary pH in relation to test performance. A prospective study. Eighty-three nursing students answered a questionnaire on stress appraisals, experienced stress, test anxiety (including worry and emotionality subscales) and health behaviors, and gave a saliva sample for measuring pH on the morning of their first term exam and three months later. Their performance on the test (grades) was also recorded. Levels of pH in saliva were higher (levels of acidity were lower) in the post exam compared to the exam period, in parallel to lower threat appraisal, experienced stress, and test anxiety levels post exam. Controlling for smoking, physical activity and working hours per week, pH levels at both time points were predicted by appraised threat regarding the exam situation, experienced stress, and the emotionality dimension of test anxiety. pH at Time 1 predicted performance on the exams and mediated the associations of experienced stress and emotionality subscale with test performance. the present study indicates that pH levels may serve as a reliable, accessible and inexpensive means by which to assess the degree of physiological reactions to exams and other naturalistic stressors. Copyright © 2014 Elsevier Inc. All rights reserved.

Mouthguard and sports drinks on tooth surface pH.

PubMed

Maeda, Y; Yang, T-C; Miyanaga, H; Tanaka, Y; Ikebe, K; Akimoto, N

2014-09-01

The influence of sports drinks and mouthguards on the pH level of tooth surface was examined. A custom-made mouthguard was fabricated for each subject. The pH level was measured by electric pH meter with sensitivity of 0.01 up to 30 min. Sports drinks (pH=3.75) containing 9.4% sugar were used in this study. Measurements were performed on a cohort of 23 female subjects without a mouthguard (control), wearing a mouthguard only (MG), wearing a mouthguard after 30 ml sports drink intake (SD+MG), wearing a mouthguard during a 5-min jogging exercise (MG+EX) and wearing a mouthguard during jogging after sports drink intake (SD+MG+EX). For 7 male subjects, the same measurements were performed while a sports drink was taken over the mouthguard (MG+SD, MD+EX+SD). MG showed statistically higher pH level than control (p<0.05). SD+MG exhibited a significant decrease in pH level, and SD+MG+EX exhibited even below the critical level of pH 5.5 in some subjects. When sports drinks were taken over the mouthguard, no significant differences in pH level were observed among the different conditions.Within the limitations of this study, it was suggested that wearing a mouthguard during exercise is in itself not a possible risk factor for dental caries, while wearing a mouthguard after consuming sports drinks is. © Georg Thieme Verlag KG Stuttgart · New York.

Effect of soil organic matter content and pH on the toxicity of ZnO nanoparticles to Folsomia candida.

PubMed

Waalewijn-Kool, Pauline L; Rupp, Svenja; Lofts, Stephen; Svendsen, Claus; van Gestel, Cornelis A M

2014-10-01

Organic matter (OM) and pH may influence nanoparticle fate and effects in soil. This study investigated the influence of soil organic matter content and pH on the toxicity of ZnO-NP and ZnCl2 to Folsomia candida in four natural soils, having between 2.37% and 14.7% OM and [Formula: see text] levels between 5.0 and 6.8. Porewater Zn concentrations were much lower in ZnO-NP than in ZnCl2 spiked soils, resulting in higher Freundlich sorption constants for ZnO-NP. For ZnCl2 the porewater Zn concentrations were significantly higher in less organic soils, while for ZnO-NP the highest soluble Zn level (23mgZn/l) was measured in the most organic soil, which had the lowest pH. Free Zn(2+) ion concentrations were higher for ZnCl2 than for ZnO-NP and were greatly dependent on pH (pHpw) and dissolved organic carbon content of the pore water. The 28-d EC50 values for the effect of ZnCl2 on the reproduction of F. candida increased with increasing OM content from 356 to 1592mgZn/kg d.w. For ZnO-NP no correlation between EC50 values and OM content was found and EC50 values ranged from 1695 in the most organic soil to 4446mgZn/kg d.w. in the higher pH soil. When based on porewater and free Zn(2+) concentrations, EC50 values were higher for ZnCl2 than for ZnO-NP, and consistently decreased with increasing pHpw. This study shows that ZnO-NP toxicity is dependent on soil properties, but is mainly driven by soil pH. Copyright © 2014 Elsevier Inc. All rights reserved.

New Nitric Oxide Donor NCX 1443: Therapeutic Effects on Pulmonary Hypertension in the SAD Mouse Model of Sickle Cell Disease.

PubMed

Abid, Shariq; Kebe, Kanny; Houssaïni, Amal; Tomberli, Françoise; Marcos, Elisabeth; Bizard, Emilie; Breau, Marielle; Parpaleix, Aurelien; Tissot, Claire-Marie; Maitre, Bernard; Lipskaia, Larissa; Derumeaux, Genevieve; Bastia, Elena; Mekontso-Dessap, Armand; Adnot, Serge

2018-05-01

Nitric oxide (NO) donors may be useful for treating pulmonary hypertension (PH) complicating sickle cell disease (SCD), as endogenous NO is inactivated by hemoglobin released by intravascular hemolysis. Here, we investigated the effects of the new NO donor NCX1443 on PH in transgenic SAD mice, which exhibit mild SCD without severe hemolytic anemia. In SAD and wild-type (WT) mice, the pulmonary pressure response to acute hypoxia was similar and was abolished by 100 mg/kg NCX1443. The level of PH was also similar in SAD and WT mice exposed to chronic hypoxia (9% O2) alone or with SU5416 and was similarly reduced by daily NCX1443 gavage. Compared with WT mice, SAD mice exhibited higher levels of HO-1, endothelial NO synthase, and PDE5 but similar levels of lung cyclic guanosine monophosphate. Cultured pulmonary artery smooth muscle cells from SAD mice grew faster than those from WT mice and had higher PDE5 protein levels. Combining NCX1443 and a PDE5 inhibitor suppressed the growth rate difference between SAD and WT cells and induced a larger reduction in hypoxic PH severity in SAD than in WT mice. By amplifying endogenous protective mechanisms, NCX1443 in combination with PDE5 inhibition may prove useful for treating PH complicating SCD.

Effect of urinary pH and nicotine excretion rate on plasma nicotine during cigarette smoking and chewing nicotine gum

PubMed Central

Feyerabend, C.; Russell, M. A. H.

1978-01-01

1 Plasma nicotine levels produced by chewing nicotine gum were compared with those obtained by cigarette smoking under conditions of controlled urinary pH. 2 Although absorption was slower, plasma levels comparable to cigarette smoking were built up on 4 mg (but not 2 mg) nicotine gum. 3 Urinary excretion of nicotine was influenced markedly by pH and the rate of urine flow. 4 Plasma nicotine was higher under alkaline compared to acidic conditions (P < 0.001) but the rate of urinary nicotine excretion appeared to have little effect on the plasma level.

Coral calcification mechanisms facilitate adaptive responses to ocean acidification.

PubMed

Schoepf, Verena; Jury, Christopher P; Toonen, Robert J; McCulloch, Malcolm T

2017-12-06

Ocean acidification (OA) is a pressing threat to reef-building corals, but it remains poorly understood how coral calcification is inhibited by OA and whether corals could acclimatize and/or adapt to OA. Using a novel geochemical approach, we reconstructed the carbonate chemistry of the calcifying fluid in two coral species using both a pH and dissolved inorganic carbon (DIC) proxy (δ 11 B and B/Ca, respectively). To address the potential for adaptive responses, both species were collected from two sites spanning a natural gradient in seawater pH and temperature, and then subjected to three pH T levels (8.04, 7.88, 7.71) crossed by two temperatures (control, +1.5°C) for 14 weeks. Corals from the site with naturally lower seawater pH calcified faster and maintained growth better under simulated OA than corals from the higher-pH site. This ability was consistently linked to higher pH yet lower DIC values in the calcifying fluid, suggesting that these differences are the result of long-term acclimatization and/or local adaptation to naturally lower seawater pH. Nevertheless, all corals elevated both pH and DIC significantly over seawater values, even under OA. This implies that high pH upregulation combined with moderate levels of DIC upregulation promote resistance and adaptive responses of coral calcification to OA. © 2017 The Author(s).

Creating opportunities for science PhDs to pursue careers in high school education

PubMed Central

Doyle, Kari M. H.; Vale, Ronald D.

2013-01-01

The United States is confronting important challenges at both the early and late stages of science education. At the level of K–12 education, a recent National Research Council report (Successful K–12 STEM Education) proposed a bold restructuring of how science is taught, moving away from memorizing facts and emphasizing hands-on, inquiry-based learning and a deeper understanding of the process of science. At higher levels of training, limited funding for science is leading PhDs to seek training and careers in areas other than research. Might science PhDs play a bigger role in the future of K–12 education, particularly at the high school level? We explore this question by discussing the roles that PhDs can play in high school education and the current and rather extensive barriers to PhDs entering the teaching profession and finally suggest ways to ease the entrance of qualified PhDs into high school education. PMID:24174464

Creating opportunities for science PhDs to pursue careers in high school education.

PubMed

Doyle, Kari M H; Vale, Ronald D

2013-11-01

The United States is confronting important challenges at both the early and late stages of science education. At the level of K-12 education, a recent National Research Council report (Successful K-12 STEM Education) proposed a bold restructuring of how science is taught, moving away from memorizing facts and emphasizing hands-on, inquiry-based learning and a deeper understanding of the process of science. At higher levels of training, limited funding for science is leading PhDs to seek training and careers in areas other than research. Might science PhDs play a bigger role in the future of K-12 education, particularly at the high school level? We explore this question by discussing the roles that PhDs can play in high school education and the current and rather extensive barriers to PhDs entering the teaching profession and finally suggest ways to ease the entrance of qualified PhDs into high school education.

Demetallization of Enterococcus faecalis biofilm: a preliminary study

PubMed Central

ESTRELA, Carlos; COSTA E SILVA, Rodrigo; URBAN, Roberta Cerasi; GONÇALVES, Pablo José; SILVA, Júlio A.; ESTRELA, Cyntia R.A.; PECORA, Jesus Djalma; PETERS, Ove A.

2018-01-01

Abstract Objectives To determine the concentration of calcium, iron, manganese and zinc ions after the application of chelator to Enterococcus faecalis biofilms. Material and Methods Fifty bovine maxillary central incisors were prepared and inoculated with E. faecalis for 60 days. The following were used as irrigation solutions: 17% EDTA (pH 3, 7 and 10), 2.5% sodium hypochlorite (NaOCl) combined with 17% EDTA (pH 3, 7 and 10), distilled water (pH 3, 7 and 10), and 2.5% NaOCl. Each solution was kept in the root canal for five minutes. Fifteen uncontaminated root canals were irrigated with 17% EDTA (pH 3, 7 and 10). Six teeth were used as bacterial control. The number of calcium, iron, manganese and zinc ions was determined using flame atomic absorption spectrometry. Mean ± standard deviation (SD) values were used for descriptive statistics. Results Calcium chelation using 17% EDTA at pH 7 was higher than at pH 3 and 10, regardless of whether bacterial biofilm was present. The highest concentration of iron occurred at pH 3 in the presence of bacterial biofilm. The highest concentration of manganese found was 2.5% NaOCl and 17% EDTA at pH 7 in the presence of bacterial biofilm. Zinc levels were not detectable. Conclusions The pH of chelating agents affected the removal of calcium, iron, and manganese ions. The concentration of iron ions in root canals with bacterial biofilm was higher after the use of 17% EDTA at pH 3 than after the use of the other solutions at all pH levels. PMID:29451651

Miniaturized pH Sensors Based on Zinc Oxide Nanotubes/Nanorods

PubMed Central

Fulati, Alimujiang; Ali, Syed M.Usman; Riaz, Muhammad; Amin, Gul; Nur, Omer; Willander, Magnus

2009-01-01

ZnO nanotubes and nanorods grown on gold thin film were used to create pH sensor devices. The developed ZnO nanotube and nanorod pH sensors display good reproducibility, repeatability and long-term stability and exhibit a pH-dependent electrochemical potential difference versus an Ag/AgCl reference electrode over a large dynamic pH range. We found the ZnO nanotubes provide sensitivity as high as twice that of the ZnO nanorods, which can be ascribed to the fact that small dimensional ZnO nanotubes have a higher level of surface and subsurface oxygen vacancies and provide a larger effective surface area with higher surface-to-volume ratio as compared to ZnO nanorods, thus affording the ZnO nanotube pH sensor a higher sensitivity. Experimental results indicate ZnO nanotubes can be used in pH sensor applications with improved performance. Moreover, the ZnO nanotube arrays may find potential application as a novel material for measurements of intracellular biochemical species within single living cells. PMID:22291545

Growth rates of three geographically separated strains of the ichthyotoxic Prymnesium parvum (Prymnesiophyceae) in response to six different pH levels

NASA Astrophysics Data System (ADS)

Lysgaard, Maria L.; Eckford-Soper, Lisa; Daugbjerg, Niels

2018-05-01

Continued anthropogenic carbon emissions are expected to cause a decline in global average pH of the oceans to a projected value of 7.8 by the end of the century. Understanding how harmful algal bloom (HAB) species will respond to lowered pH levels will be important when predicting future HAB events and their ecological consequences. In this study, we examined how manipulated pH levels affected the growth rate of three strains of Prymnesium parvum from North America, Denmark and Japan. Triplicate strains were grown under pH conditions ranging from 6.6 to 9.1 to simulate plausible future levels. Different tolerances were evident for all strains. Significantly higher growth rates were observed at pH 6.6-8.1 compared to growth rates at pH 8.6-9.1 and a lower pH limit was not observed. The Japanese strain (NIES-1017) had the highest maximum growth rate of 0.39 divisions day-1 at pH 6.6 but a low tolerance (0.22 divisions day-1) to high levels (pH 9.1) with growth declining markedly after pH 7.6. The Danish (SCCAP K-0081) and North American (UTEX LB 2797) strains had maximum growth rates of 0.26 and 0.35 divisions day-1, respectively between pH 6.6-8.1. Compared to the other two strains the Danish strain had a statistically lower growth rate across all pH treatments. Strain differences were either attributed to their provenance or the length of time the strain had been in culture.

Dental plaque pH and ureolytic activity in children and adults of a low caries population.

PubMed

Appelgren, Linnea; Dahlén, Anna; Eriksson, Cecilia; Suksuart, Narong; Dahlén, Gunnar

2014-04-01

The aim of this study was to evaluate the plaque pH level and ureolytic activity among children and adults of Karen Hill tribes. Thirty-four children aged 6-10 years and 46 adults aged 20-38 years were interviewed regarding oral hygiene practices, sucrose intake and betel chewing. Caries experience (DMFT and DT), calculus, bleeding on probing (BoP) and Plaque index (PlI) were registered. Ureolytic activity in supragingival plaque was tested at two interproximal sites (11/12 and 41/42) with the rapid urease test (RUT). Registration of plaque pH was performed at two interproximal sites (15/16 and 31/41) before, during and 30 min after rinsing with an urea solution (0.25%). Four interproximal plaque samples (one from each quadrant) per individual were collected to test the bacterial composition using the checkerboard technique. Children and adults had similarly low DMFT and DT values. Children had a higher baseline pH and a higher ureolytic activity in the maxilla (p < 0.05) compared with adults. A significant correlation (r (2) = 0.63) was found between baseline pH and urease activity in the mandibular anterior teeth. Caries-free individuals had a higher baseline pH compared with caries active individuals in the anterior mandibular region (p < 0.01). The microbiological composition was characterized by an anaerobic low acidiogenic microbiota. Dental plaque pH is related to the ureolytic activity, which explains the low acidogenic plaque microflora and the low caries levels in the Karen population.

Nanoparticle-based measurements of pH and O2 dynamics in the rhizosphere of Zostera marina L.: effects of temperature elevation and light-dark transitions.

PubMed

Elgetti Brodersen, Kasper; Koren, Klaus; Lichtenberg, Mads; Kühl, Michael

2016-07-01

Seagrasses can modulate the geochemical conditions in their immediate rhizosphere through the release of chemical compounds from their below-ground tissue. This is a vital chemical defence mechanism, whereby the plants detoxify the surrounding sediment. Using novel nanoparticle-based optical O2 and pH sensors incorporated in reduced and transparent artificial sediment, we investigated the spatio-temporal dynamics of pH and O2 within the entire rhizosphere of Zostera marina L. during experimental manipulations of light and temperature. We combined such measurements with O2 microsensor measurements of the photosynthetic productivity and respiration of seagrass leaves. We found pronounced pH and O2 microheterogeneity within the immediate rhizosphere of Z. marina, with higher below-ground tissue oxidation capability and rhizoplane pH levels during both light exposure of the leaf canopy and elevated temperature, where the temperature-mediated stimuli of biogeochemical processes seemed to predominate. Low rhizosphere pH microenvironments appeared to correlate with plant-derived oxic microzones stimulating local sulphide oxidation and thus driving local proton generation, although the rhizoplane pH levels generally where much higher than the bulk sediment pH. Our data show that Z. marina can actively alter its rhizosphere pH microenvironment alleviating the local H2 S toxicity and enhancing nutrient availability in the adjacent sediment via geochemical speciation shift. © 2016 John Wiley & Sons Ltd.

Improvement of the respiration efficiency of Lactococcus lactis by decreasing the culture pH.

PubMed

Shi, Weijia; Li, Yu; Gao, Xueling; Fu, Ruiyan

2016-03-01

The growth characteristics and intracellular hemin concentrations of Lactococcus lactis grown under different culture pH and aeration conditions were examined to investigate the effect of culture pH on the respiration efficiency of L. lactis NZ9000 (pZN8148). Cell biomass and biomass yield of L. lactis grown with 4 μg hemin/ml and O2 were higher than those without aeration when the culture pH was controlled at 5-6.5. The culture pH affected the respiratory efficiency in the following order of pH: 5 > 5.5 > 6 > 6.5; the lag phase increased as the culture pH decreased. Hemin accumulation was sensitive to culture pH. Among the four pH conditions, pH 5.5 was optimal for hemin accumulation in the cells. The highest intracellular hemin level in L. lactis resting cells incubated at different pH saline levels (5-6.5) was at pH 5.5. The respiration efficiency of L. lactis under respiration-permissive conditions increases markedly as the culture pH decreases. These results may help develop high cell-density L. lactis cultures. Thus, this microorganism may be used for industrial applications.

Transcription of the pst Operon of Clostridium acetobutylicum Is Dependent on Phosphate Concentration and pH

PubMed Central

Fischer, Ralf-Jörg; Oehmcke, Sonja; Meyer, Uta; Mix, Maren; Schwarz, Katrin; Fiedler, Tomas; Bahl, Hubert

2006-01-01

The pst operon of Clostridium acetobutylicum ATCC 824 comprises five genes, pstS, pstC, pstA, pstB, and phoU, and shows a gene architecture identical to that of Escherichia coli. Deduced proteins are predicted to represent a high-affinity phosphate-specific ABC (ATP-binding cassette) transport system (Pst) and a protein homologous to PhoU, a negative phosphate regulon regulator. We analyzed the expression patterns of the pst operon in Pi-limited chemostat cultures during acid production at pH 5.8 or solvent production at pH 4.5 and in response to Pi pulses. Specific mRNA transcripts were found only when external Pi concentrations had dropped below 0.2 mM. Two specific transcripts were detected, a 4.7-kb polycistronic mRNA spanning the whole operon and a quantitatively dominating 1.2-kb mRNA representing the first gene, pstS. The mRNA levels clearly differed depending on the external pH. The amounts of the full-length mRNA detected were about two times higher at pH 5.8 than at pH 4.5. The level of pstS mRNA increased by a factor of at least 8 at pH 5.8 compared to pH 4.5 results. Primer extension experiments revealed only one putative transcription start point 80 nucleotides upstream of pstS. Thus, additional regulatory sites are proposed in the promoter region, integrating two different extracellular signals, namely, depletion of inorganic phosphate and the pH of the environment. After phosphate pulses were applied to a phosphate-limited chemostat we observed faster phosphate consumption at pH 5.8 than at pH 4.5, although higher optical densities were recorded at pH 4.5. PMID:16855236

[Inhibition of Bacillus coagulans growth in laboratory media and in fruit purees].

PubMed

Cerrutti, P; Alzamora, S M; de Huergo, M S

2000-01-01

The growth of two strains of B. coagulans was inhibited in laboratory media at pH < or = 4.5, and at water activity (aw) levels of 0.96 for B. coagulans NRS 609 and 0.95 for B. coagulans ATCC 803. The growth of both strains was also inhibited in apple and strawberry purees (pH = 3.5) stored at 37 degrees C for over two months. B. coagulans was able to grow in banana puree (pH approximately equal to 5.0) but acidification of the puree at pH = 3.5 was enough to prevent growth. The addition of up to 3,000 ppm vainillin ("natural" preservative) or 1,000 ppm potassium sorbate (traditional preservative) at pH higher than the inhibitory level previously determined could not prevent growth of B. coagulans in laboratory or in fruits, but 100 ppm lysozyme retarded growth in laboratory media at different pH levels (from 4.5 to 6.7) and in banana puree. As lysozyme showed to be effective at pH < or = 6.7, it might be used to prevent growth of B. coagulans at an eventual increment of pH during storage.

Levels of Candidate Periodontal Pathogens in Subgingival Biofilm

PubMed Central

Oliveira, R.R.D.S.; Fermiano, D.; Feres, M.; Figueiredo, L.C.; Teles, F.R.F.; Soares, G.M.S.; Faveri, M.

2016-01-01

In recent years, several new periodontal taxa have been associated with the etiology of periodontitis. A recent systematic review provides further support for the pathogenic role of 17 species/phylotypes. Thus, the aim of this study was to assess the prevalence and levels of these species in subjects with generalized chronic periodontitis (GChP; n = 30), generalized aggressive periodontitis (GAgP; n = 30), and periodontal health (PH; n = 30). All subjects underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analyzed for their content of 20 bacterial species/phylotypes through the RNA-oligonucleotide quantification technique. Subjects from the GChP and GAgP groups presented the highest mean values for all clinical parameters in comparison with the PH group (P < 0.05). Subjects with GChP and GAgP showed significantly higher mean levels of Bacteroidetes sp. human oral taxon (HOT) 274, Fretibacterium sp. HOT 360, and TM7 sp. HOT 356 phylotypes, as well as higher mean levels of Filifactor alocis, Fretibacterium fastidiosum, Porphyromonas gingivalis, Tannerella forsythia, and Selenomonas sputigena species than PH subjects (P < 0.05). GAgP subjects presented higher mean levels of TM7 sp. HOT 356 and F. alocis than GChP subjects (P < 0.05). A significantly higher mean prevalence of Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, and Fretibacterium sp. HOT 362 was found in subjects with GChP and GAgP than in PH subjects. Mean levels of P. gingivalis (r = 0.68), T. forsythia (r = 0.62), F. alocis (r = 0.51, P = 0.001), and Fretibacterium sp. HOT 360 (r = 0.41) were correlated with pocket depth (P < 0.001). In conclusion, Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, Fretibacterium sp. HOT 362, and TM7 sp. HOT 356 phylotypes, in addition to F. alocis, F. fastidiosum, and S. sputigena, seem to be associated with periodontitis, and their role in periodontal pathogenesis should be further investigated. PMID:26936213

High concentrations of the carcinogen 2-amino-1-methyl-6-phenylimidazo- [4,5-b]pyridine (PhIP) occur in chicken but are dependent on the cooking method.

PubMed

Sinha, R; Rothman, N; Brown, E D; Salmon, C P; Knize, M G; Swanson, C A; Rossi, S C; Mark, S D; Levander, O A; Felton, J S

1995-10-15

Heterocyclic aromatic amines (HAAs) are mutagenic and carcinogenic compounds found in meats cooked at high temperatures. Although chicken is consumed in large quantities in the United States, there is little information on its HAA content. The objective of this study was to measure the five predominant HAAs (IQ, MeIQ, MeIQx, DiMeIQx, and PhIP) in chicken cooked by various methods to different degrees of doneness. Chicken breasts were panfried, oven-broiled, or grilled/barbecued. Whole chickens were roasted or stewed. Skinless, boneless chicken breasts were cooked to three degrees of doneness: just until done, well done, or very well done. High levels of PhIP (ranging from 12 to 480 ng/g cooked meat) were found in chicken breasts when panfried, oven-broiled, and grilled/barbecued but not in while roasted or stewed chicken. PhIP concentration increased in skinless, boneless chicken breast with longer cooking time, higher internal temperature, and greater degree of surface browning. PhIP concentration was also high in chicken breasts cooked with skin and bones. MeIQx and DiMeIQx levels increased with the degree of doneness, whereas IQ and MeIQ were not detectable in any of these chicken samples. Certain cooking methods produce PhIP, a known colon and breast carcinogen in rodents and possibly a human carcinogen, at substantially higher levels in chicken than has been reported previously in red meat.

PhMYB4 fine-tunes the floral volatile signature of Petunia x hybrida through PhC4H.

PubMed

Colquhoun, Thomas A; Kim, Joo Young; Wedde, Ashlyn E; Levin, Laura A; Schmitt, Kyle C; Schuurink, Robert C; Clark, David G

2011-01-01

In Petunia × hybrida cv 'Mitchell Diploid' (MD), floral volatile benzenoid/phenylpropanoid (FVBP) biosynthesis is controlled spatially, developmentally, and daily at molecular, metabolic, and biochemical levels. Multiple genes have been shown to encode proteins that either directly catalyse a biochemical reaction yielding FVBP compounds or are involved in metabolite flux prior to the formation of FVBP compounds. It was hypothesized that multiple transcription factors are involved in the precise regulation of all necessary genes, resulting in the specific volatile signature of MD flowers. After acquiring all available petunia transcript sequences with homology to Arabidopsis thaliana R2R3-MYB transcription factors, PhMYB4 (named for its close identity to AtMYB4) was identified, cloned, and characterized. PhMYB4 transcripts accumulate to relatively high levels in floral tissues at anthesis and throughout open flower stages, which coincides with the spatial and developmental distribution of FVBP production and emission. Upon RNAi suppression of PhMYB4 (ir-PhMYB4) both petunia cinnamate-4-hydroxylase (PhC4H1 and PhC4H2) gene transcript levels were significantly increased. In addition, ir-PhMYB4 plants emit higher levels of FVBP compounds derived from p-coumaric acid (isoeugenol and eugenol) compared with MD. Together, these results indicate that PhMYB4 functions in the repression of C4H transcription, indirectly controlling the balance of FVBP production in petunia floral tissue (i.e. fine-tunes).

Effects of humoral factors on ventilation kinetics during recovery after impulse-like exercise.

PubMed

Afroundeh, R; Arimitsu, T; Yamanaka, R; Lian, C; Yunoki, T; Yano, Tokuo

2012-06-01

To clarify the ventilatory kinetics during recovery after impulse-like exercise, subjects performed one impulse-like exercise test (one-impulse) and a five-times repeated impulse-like exercises test (five-impulse). Duration and intensity of the impulse-like exercise were 20 sec and 400 watts (80 rpm), respectively. Although blood pH during recovery (until 10 min) was significantly lower in the five-impulse test than in the one-impulse test, ventilation (.VE) in the two tests was similar except during the first 30 sec of recovery, in which it was higher in the five-impulse test. In one-impulse, blood CO2 pressure (PCO2) was significantly increased at 1 min during recovery and then returned to the pre-exercise level at 5 min during recovery. In the five-impulse test, PCO2 at 1 min during recovery was similar to the pre-exercise level, and then it decreased to a level lower than the pre-exercise level at 5 min during recovery. Accordingly, PCO2 during recovery (until 30 min) was significantly lower in the five-impulse than in one-impulse test..VE and pH during recovery showed a curvilinear relationship, and at the same pH, ventilation was higher in the one-impulse test. These results suggest that ventilatory kinetics during recovery after impulse-like exercise is attributed partly to pH, but the stimulatory effect of lower pH is diminished by the inhibitory effect of lower PCO2.

Relationship between symptom response and esophageal pH level on standard dose of esomeprazole treatment for gastroesophageal reflux disease.

PubMed

Peng, Sui; Xiong, Li-shou; Xiao, Ying-lian; Wang, An-jiang; Lin, Jin-kun; Hu, Pin-jin; Chen, Min-hu

2010-08-05

The relationship between symptom elimination and normalization of esophageal acid level of gastroesophageal reflux disease (GERD) on proton-pump inhibitor (PPI) therapy has been questioned. This study aimed to evaluate the relationship between symptom response and gastro-esophageal acidity control in Chinese patients with GERD on esomeprazole therapy, and to assess the role of 24-hour esophageal pH-metry after therapy in GERD patients. GERD patients with typical reflux symptoms were enrolled and received esomeprazole 40 mg once daily for 4 weeks. Patients with positive baseline 24-hour esophageal pH-metry were divided into two groups depending on an additional dual-channel 24-hour pH-metry after treatment. The pH- group achieved normalization of esophageal pH level whereas the pH+ group did not. Of the 80 patients studied, 76 had abnormal baseline esophageal pH levels. Of these, 90% (52/58) of symptom-free patients and 67% (12/18) of symptom-persistent patients achieved esophageal pH normalization after therapy (P = 0.030). The mean post-therapy gastric nocturnal percent time of pH < 4.0 was significantly higher in pH+ group than that in pH- group (P < 0.001) after therapy. The multivariate regression analysis identified hiatus hernia (P < 0.001) and persistent reflux symptom (P = 0.004) were two independent factors predicting the low post-therapy esophageal pH level. Symptom elimination is not always accompanied by esophageal pH normalization, and vice verse. Esophageal pH-metry is recommended for GERD patients with hiatus hernia or with persistent reflux symptoms after PPI therapy.

High fluoride and low pH level have been detected in popular flavoured beverages in Malaysia

PubMed Central

HA Rahim, Zubaidah; M Bakri, Marina; HM, Zakir; IA, Ahmed; NA, Zulkifli

2014-01-01

Objective: In children, excessive ingestion of fluoride from different sources including bottled drinking water and flavoured beverages or soft drinks can lead to the development of dental fluorosis. In addition, the pH level of beverages is important. Low pH can cause dental erosion. In this study we explore the fluoride content and pH level of certain popular beverages available in Malaysian supermarkets and hawkers’ stalls. Methods: Bottled drinking water and selected popular flavoured packet drinks were purchased from a supermarket and the corresponding flavoured hawkers’ drinks, from a hawker’s stall in Kuala Lumpur. Fluoride and pH of the beverages were determined using digital fluoride meter and digital pH meter respectively. Results: It was found that fluoride content and pH level vary among the beverages. The mean fluoride content in both packet and hawkers’ drinks (7.64±1.88 mg/L, 7.51±1.60 mg/L, respectively) was approximately 7 times higher than the bottled drinking water (1.05±0.35 mg/L). Among the beverages, the tea packet drink was found to contain the highest amount of fluoride (13.02±0.23 mg/L). The mean pH of bottled-drinking water was near neutral (6.96±0.17), but acidic for both supermarket (4.78.00±0.49) and hawkers’ drinks (5.73±0.24). The lychee packet drink had the lowest pH level (2.97±0.03). Conclusions: Due to the wide variation of the fluoride content and pH level of the drinks tested in this study, it is recommended that steps should be taken to control the fluoride concentration and pH level in beverages if dental fluorosis and erosion are to be prevented. PMID:24772152

Correlations among Stress Parameters, Meat and Carcass Quality Parameters in Pigs

PubMed Central

Dokmanovic, Marija; Baltic, Milan Z.; Duric, Jelena; Ivanovic, Jelena; Popovic, Ljuba; Todorovic, Milica; Markovic, Radmila; Pantic, Srdan

2015-01-01

Relationships among different stress parameters (lairage time and blood level of lactate and cortisol), meat quality parameters (initial and ultimate pH value, temperature, drip loss, sensory and instrumental colour, marbling) and carcass quality parameters (degree of rigor mortis and skin damages, hot carcass weight, carcass fat thickness, meatiness) were determined in pigs (n = 100) using Pearson correlations. After longer lairage, blood lactate (p<0.05) and degree of injuries (p<0.001) increased, meat became darker (p<0.001), while drip loss decreased (p<0.05). Higher lactate was associated with lower initial pH value (p<0.01), higher temperature (p<0.001) and skin blemishes score (p<0.05) and more developed rigor mortis (p<0.05), suggesting that lactate could be a predictor of both meat quality and the level of preslaughter stress. Cortisol affected carcass quality, so higher levels of cortisol were associated with increased hot carcass weight, carcass fat thickness on the back and at the sacrum and marbling, but also with decreased meatiness. The most important meat quality parameters (pH and temperature after 60 minutes) deteriorated when blood lactate concentration was above 12 mmol/L. PMID:25656214

Physicochemical degradation studies of calcium phosphate glass ceramic in the CaO-P2O5-MgO-TiO2 system.

PubMed

Dias, A G; Gibson, I R; Santos, J D; Lopes, M A

2007-03-01

The aim of this work was to evaluate the in vitro degradation behaviour of a 45CaO-37P(2)O(5)-5MgO-13TiO(2) (mol.%) glass ceramic, under two different simulated physiological conditions: normal physiological pH 7.4, and pH 3.0, which was designed to simulate the acidic conditions produced by osteoclast cells. The in vitro testing was carried out at 37 degrees C for up to 42 days for the pH 7.4 solution and for up to 1 day for the pH 3.0 solution. The incorporation of TiO(2) into the glass structure leads to the precipitation of specific crystalline phases in the glass matrix, namely alpha- and beta-Ca(2)P(2)O(7), TiP(2)O(7) and CaTi(4)(PO(4))(6). The degradation testing at pH 3.0 showed a higher weight loss compared with degradation testing at pH 7.4; the weight loss under the acidic condition after 1 day (24 h) was about 10 times higher than the weight loss after 42 days of immersion at pH 7.4. The ionic release profile of Ca(2+), PO(4)(3-), Mg(2+) and Ti(4+) showed a continuous increase in concentration over all immersion times for both testing solutions. After 1 day of immersion at pH 3.0, the concentration levels of Mg(2+), Ca(2+), PO(4)(3-) were about six times higher than the levels achieved after 42 days of immersion at pH 7.4. The glass ceramic showed similar degradation to hydroxyapatite, and therefore has potential to be used in certain clinical applications where relatively slow resorption of the implant and replacement by bone is required, e.g. cranioplasty.

Influence of soil pH on the toxicity of zinc oxide nanoparticles to the terrestrial isopod Porcellionides pruinosus.

PubMed

Tourinho, Paula S; van Gestel, Cornelis A M; Lofts, Stephen; Soares, Amadeu M V M; Loureiro, Susana

2013-12-01

The effects of soil pH on the toxicity of ZnO nanoparticles (NPs) to the terrestrial isopod Porcellionides pruinosus were evaluated. Isopods were exposed to a natural soil amended with CaCO3 to reach 3 different pH(CaCl2) levels (4.5, 6.2, and 7.3) and to standard LUFA 2.2 soil (pH 5.5) spiked with ZnO NPs (30 nm), non-nano ZnO (200 nm), and ionic Zn as ZnCl₂. Toxicity was expressed based on total Zn concentration in soil, as well as total Zn and free Zn²⁺ ion concentrations in porewater. Compared with ZnO-spiked soils, the ZnCl₂-spiked soils had lower pH and higher porewater Ca²⁺ and Zn levels. Isopod survival did not differ between Zn forms and soils, but survival was higher for isopods exposed to ZnO NPs at pH 4.5. Median effect concentrations (EC50s) for biomass change showed similar trends for all Zn forms in all soils, with higher values at intermediate pH. Median lethal concentration (LC50) and EC50 values based on porewater Zn or free Zn ion concentrations were much lower for ZnO than for ionic zinc. Zn body concentrations increased in a dose-related manner, but no effect of soil pH was found. It is suggested not only that dissolved or free Zn in porewater contributed to uptake and toxicity, but also that oral uptake (i.e., ingestion of soil particles) could be an important additional route of exposure. © 2013 SETAC.

Cytochrome b5 Reductase 1 Triggers Serial Reactions that Lead to Iron Uptake in Plants.

PubMed

Oh, Young Jun; Kim, Hanul; Seo, Sung Hee; Hwang, Bae Geun; Chang, Yoon Seok; Lee, Junho; Lee, Dong Wook; Sohn, Eun Ju; Lee, Sang Joon; Lee, Youngsook; Hwang, Inhwan

2016-04-04

Rhizosphere acidification is essential for iron (Fe) uptake into plant roots. Plasma membrane (PM) H(+)-ATPases play key roles in rhizosphere acidification. However, it is not fully understood how PM H(+)-ATPase activity is regulated to enhance root Fe uptake under Fe-deficient conditions. Here, we present evidence that cytochrome b5 reductase 1 (CBR1) increases the levels of unsaturated fatty acids, which stimulate PM H(+)-ATPase activity and thus lead to rhizosphere acidification. CBR1-overexpressing (CBR1-OX) Arabidopsis thaliana plants had higher levels of unsaturated fatty acids (18:2 and 18:3), higher PM H(+)-ATPase activity, and lower rhizosphere pH than wild-type plants. By contrast, cbr1 loss-of-function mutant plants showed lower levels of unsaturated fatty acids and lower PM H(+)-ATPase activity but higher rhizosphere pH. Reduced PM H(+)-ATPase activity in cbr1 could be restored in vitro by addition of unsaturated fatty acids. Transcript levels of CBR1, fatty acids desaturase2 (FAD2), and fatty acids desaturase3 (FAD3) were increased under Fe-deficient conditions. We propose that CBR1 has a crucial role in increasing the levels of unsaturated fatty acids, which activate the PM H(+)-ATPase and thus reduce rhizosphere pH. This reaction cascade ultimately promotes root Fe uptake. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

Physiological response of a red tide alga (Skeletonema costatum) to nitrate enrichment, with special reference to inorganic carbon acquisition.

PubMed

Gao, Guang; Xia, Jianrong; Yu, Jinlan; Zeng, Xiaopeng

2018-02-01

A classical red tide alga Skeletonema costatum was cultured under various nitrate levels to investigate its physiological response to nitrate enrichment combined with CO 2 limitation. The higher nitrate levels increased content of photosynthetic pigments (Chl a and Chl c), electron transport rate in photosystem II, photosynthetic O 2 evolution, and thus growth rate in S. costatum. On the other hand, the lower CO 2 levels (3.5-4.4 μmol kg -1 seawater) and higher pH (8.56-8.63) values in seawater were observed under higher nitrate conditions. Redox activity of plasma membrane and carbonic anhydrase in S. costatum was enhanced to address the reduced CO 2 level at higher nitrate levels. In addition, the pH compensation point was enhanced and direct HCO 3 - use was induced at higher nitrate levels. These findings indicate that nitrate enrichment would stimulate the breakout of S. costatum dominated red tides via enhancing its photosynthetic performances, and maintain a quick growth rate under CO 2 limitation conditions through improving its inorganic carbon acquisition capability. Our study sheds light on the mechanisms of S. costatum defeating CO 2 limitation during algal bloom. Copyright © 2017 Elsevier Ltd. All rights reserved.

Correlation between unstimulated salivary flow, pH and streptococcus mutans, analysed with real time PCR, in caries-free and caries-active children.

PubMed

Abbate, G M; Borghi, D; Passi, A; Levrini, L

2014-03-01

Evaluate the correlations between unstimulated salivary flow, pH and level of S. mutans, analysed through real time PCR, in caries-free and caries-active children. Thirty healthy children were divided into 2 groups: test group (DMFT/dmft ≥ 3 and at least 1 active caries lesion) and control group (DMFT/dmft=0). Un-stimulated saliva was collected, pH was measured and S. mutans and total bacterial amount were evaluated with real-time PCR analysis. Unstimulated salivary flow in the test group was significantly lower (p = 0.0269) compared to group control. The level of S. mutans was higher in the test group (p = 0.176), and an inverse correlation was recorded between total bacterial amount and un-stimulated salivary flow (p = 0.063). In the control group a positive relationship was found between total bacterial amount and S. mutans (p = 0.045) and an inverse correlation between pH and S. mutans (p = 0.088). A t-test and a linear regression analysis were performed. A higher salivary flow and an increased salivary pH seem to represent protective factors against caries in children, while high levels of S. mutans are correlated with caries active lesions. Caries risk assessment should be performed considering all parameters involved in the development of the disease.

Decreased Brain pH as a Shared Endophenotype of Psychiatric Disorders

PubMed Central

Hagihara, Hideo; Catts, Vibeke S; Katayama, Yuta; Shoji, Hirotaka; Takagi, Tsuyoshi; Huang, Freesia L; Nakao, Akito; Mori, Yasuo; Huang, Kuo-Ping; Ishii, Shunsuke; Graef, Isabella A; Nakayama, Keiichi I; Shannon Weickert, Cynthia; Miyakawa, Tsuyoshi

2018-01-01

Although the brains of patients with schizophrenia and bipolar disorder exhibit decreased brain pH relative to those of healthy controls upon postmortem examination, it remains controversial whether this finding reflects a primary feature of the diseases or is a result of confounding factors such as medication and agonal state. To date, systematic investigation of brain pH has not been undertaken using animal models that can be studied without confounds inherent in human studies. In the present study, we first reevaluated the pH of the postmortem brains of patients with schizophrenia and bipolar disorder by conducting a meta-analysis of existing data sets from 10 studies. We then measured pH, lactate levels, and related metabolite levels in brain homogenates from five neurodevelopmental mouse models of psychiatric disorders, including schizophrenia, bipolar disorder, and autism spectrum disorder. All mice were drug naive with the same agonal state, postmortem interval, and age within each strain. Our meta-analysis revealed that brain pH was significantly lower in patients with schizophrenia and bipolar disorder than in control participants, even when a few potential confounding factors (postmortem interval, age, and history of antipsychotic use) were considered. In animal experiments, we observed significantly lower pH and higher lactate levels in the brains of model mice relative to controls, as well as a significant negative correlation between pH and lactate levels. Our findings suggest that lower pH associated with increased lactate levels is not a mere artifact, but rather implicated in the underlying pathophysiology of schizophrenia and bipolar disorder. PMID:28776581

Cognitive disparities, lead plumbing, and water chemistry: prior exposure to water-borne lead and intelligence test scores among World War Two U.S. Army enlistees.

PubMed

Ferrie, Joseph P; Rolf, Karen; Troesken, Werner

2012-01-01

Higher prior exposure to water-borne lead among male World War Two U.S. Army enlistees was associated with lower intelligence test scores. Exposure was proxied by urban residence and the water pH levels of the cities where enlistees lived in 1930. Army General Classification Test scores were six points lower (nearly 1/3 standard deviation) where pH was 6 (so the water lead concentration for a given amount of lead piping was higher) than where pH was 7 (so the concentration was lower). This difference rose with time exposed. At this time, the dangers of exposure to lead in water were not widely known and lead was ubiquitous in water systems, so these results are not likely the effect of individuals selecting into locations with different levels of exposure. Copyright © 2011 Elsevier B.V. All rights reserved.

Excess glycogen does not resolve high ultimate pH of oxidative muscle.

PubMed

England, Eric M; Matarneh, Sulaiman K; Oliver, Emily M; Apaoblaza, Ariel; Scheffler, Tracy L; Shi, Hao; Gerrard, David E

2016-04-01

Skeletal muscle glycogen content can impact the extent of postmortem pH decline. Compared to glycolytic muscles, oxidative muscles contain lower glycogen levels antemortem which may contribute to the higher ultimate pH. In an effort to explore further the participation of glycogen in postmortem metabolism, we postulated that increasing the availability of glycogen would drive additional pH decline in oxidative muscles to equivalent pH values similar to the ultimate pH of glycolytic muscles. Glycolysis and pH declines were compared in porcine longissimus lumborum (glycolytic) and masseter (oxidative) muscles using an in vitro system in the presence of excess glycogen. The ultimate pH of the system containing longissimus lumborum reached a value similar to that observed in intact muscle. The pH decline of the system containing masseter samples stopped prematurely resulting in a higher ultimate pH which was similar to that of intact masseter muscle. To investigate further, we titrated powdered longissimus lumborum and masseter samples in the reaction buffer. As the percentage of glycolytic sample increased, the ultimate pH decreased. These data show that oxidative muscle produces meat with a high ultimate pH regardless of glycogen content and suggest that inherent muscle factors associated with glycolytic muscle control the extent of pH decline in pig muscles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of pH and Total Soluble Solids on Enzyme Inactivation Kinetics during High Pressure Processing of Mango (Mangifera indica) Pulp.

PubMed

Kaushik, Neelima; Nadella, Tejaswi; Rao, P Srinivasa

2015-11-01

This study was undertaken with an aim to enhance the enzyme inactivation during high pressure processing (HPP) with pH and total soluble solids (TSS) as additional hurdles. Impact of mango pulp pH (3.5, 4.0, 4.5) and TSS (15, 20, 25 °Brix) variations on the inactivation of pectin methylesterase (PME), polyphenol oxidase (PPO), and peroxidase (POD) enzymes were studied during HPP at 400 to 600 MPa pressure (P), 40 to 70 °C temperature (T), and 6- to 20-min pressure-hold time (t). The enzyme inactivation (%) was modeled using second order polynomial equations with a good fit that revealed that all the enzymes were significantly affected by HPP. Response surface and contour models predicted the kinetic behavior of mango pulp enzymes adequately as indicated by the small error between predicted and experimental data. The predicted kinetics indicated that for a fixed P and T, higher pulse pressure effect and increased isobaric inactivation rates were possible at lower levels of pH and TSS. In contrast, at a fixed pH or TSS level, an increase in P or T led to enhanced inactivation rates, irrespective of the type of enzyme. PPO and POD were found to have similar barosensitivity, whereas PME was found to be most resistant to HPP. Furthermore, simultaneous variation in pH and TSS levels of mango pulp resulted in higher enzyme inactivation at lower pH and TSS during HPP, where the effect of pH was found to be predominant than TSS within the experimental domain. Exploration of additional hurdles such as pH, TSS, and temperature for enzyme inactivation during high pressure processing of fruits is useful from industrial point of view, as these parameters play key role in preservation process design. © 2015 Institute of Food Technologists®

Metabolic activation of 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine and DNA adduct formation depends on p53: Studies in Trp53(+/+),Trp53(+/-) and Trp53(-/-) mice.

PubMed

Krais, Annette M; Speksnijder, Ewoud N; Melis, Joost P M; Singh, Rajinder; Caldwell, Anna; Gamboa da Costa, Gonçalo; Luijten, Mirjam; Phillips, David H; Arlt, Volker M

2016-02-15

The expression of the tumor suppressor p53 can influence the bioactivation of, and DNA damage induced by, the environmental carcinogen benzo[a]pyrene, indicating a role for p53 in its cytochrome P450 (CYP)-mediated biotransformation. The carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), which is formed during the cooking of food, is also metabolically activated by CYP enzymes, particularly CYP1A2. We investigated the potential role of p53 in PhIP metabolism in vivo by treating Trp53(+/+), Trp53(+/-) and Trp53(-/-) mice with a single oral dose of 50 mg/kg body weight PhIP. N-(Deoxyguanosin-8-yl)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP-C8-dG) levels in DNA, measured by liquid chromatography-tandem mass spectrometry, were significantly lower in liver, colon, forestomach and glandular stomach of Trp53(-/-) mice compared to Trp53(+/+) mice. Lower PhIP-DNA adduct levels in the livers of Trp53(-/-) mice correlated with lower Cyp1a2 enzyme activity (measured by methoxyresorufin-O-demethylase activity) in these animals. Interestingly, PhIP-DNA adduct levels were significantly higher in kidney and bladder of Trp53(-/-) mice compared to Trp53(+/+) mice, which was accompanied by higher sulfotransferase (Sult) 1a1 protein levels and increased Sult1a1 enzyme activity (measured by 2-naphthylsulfate formation from 2-naphthol) in kidneys of these animals. Our study demonstrates a role for p53 in the metabolism of PhIP in vivo, extending previous results on a novel role for p53 in xenobiotic metabolism. Our results also indicate that the impact of p53 on PhIP biotransformation is tissue-dependent and that in addition to Cyp1a enzymes, Sult1a1 can contribute to PhIP-DNA adduct formation. © 2015 The Authors International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.

Acute toxicity (LC50) of ammonia to carp fish (Cyprinus carpio) at different pH Levels

NASA Astrophysics Data System (ADS)

Ardeniswan; Dara, F.; Sukmawati, F.

2017-03-01

Mass death of carp fish in reservoirs and lakes in Indonesia is due to the up-welling phenomenon of ammonia generates from the decomposition of fish feed remaining in the bottom of the lakes/reservoirs by microbes. The formation of ammonia gas is very dependent on pH. Most of the ammonia gas is formed form at the high pH value. Ammonia concentration can be determined with indophenol blue method using UV-Vis spectrophotometer. Carp fish (Cyprinus carpio of 5-6 gr was exposed to the three concentration of ammonia. Acute toxicity (LC50) of ammonia (NH3) was tested on similar sizes (5-6 g) of carp fish was maintained at three different pH levels within range of 7-9 for 96-h. Results showed that the concentration of ammonia increased at higher pH. The 96-h LC50’s for exposure to ammonia were 60% (NH3 1.85 ppm at pH 8), 100% (NH3 2.16 ppm at pH 9), and insignificant result at NH3 1.68 ppm with pH 7.

Media use and communication inequalities in a public health emergency: a case study of 2009-2010 pandemic influenza A virus subtype H1N1.

PubMed

Lin, Leesa; Jung, Minsoo; McCloud, Rachel F; Viswanath, Kasisomayajula

2014-01-01

Studies have shown that differences among individuals and social groups in accessing and using information on health and specific threats have an impact on their knowledge and behaviors. These differences, characterized as communication inequalities, may hamper the strength of a society's response to a public health emergency. Such inequalities not only make vulnerable populations subject to a disproportionate burden of adversity, but also compromise the public health system's efforts to prevent and respond to pandemic influenza outbreaks. We investigated the effect of socioeconomic status (SES) and health communication behaviors (including barriers) on people's knowledge and misconceptions about pandemic influenza A(H1N1) (pH1N1) and adoption of prevention behaviors. The data for this study came from a survey of 1,569 respondents drawn from a nationally representative sample of American adults during pH1N1. We conducted logistic regression analyses when appropriate. We found that (1) SES has a significant association with barriers to information access and processing, levels of pH1N1-related knowledge, and misconceptions; (2) levels of pH1N1-related knowledge are associated positively with the adoption of recommended prevention measures and negatively with the adoption of incorrect protective behaviors; and (3) people with higher SES, higher news exposure, and higher levels of pH1N1-related knowledge, as well as those who actively seek information, are less likely than their counterparts to adopt incorrect prevention behaviors. Strategic public health communication efforts in public health preparedness and during emergencies should take into account potential communication inequalities and develop campaigns that reach across different social groups.

A comparison of sports and energy drinks--Physiochemical properties and enamel dissolution.

PubMed

Jain, Poonam; Hall-May, Emily; Golabek, Kristi; Agustin, Ma Zenia

2012-01-01

The consumption of sports and energy drinks by children and adolescents has increased at an alarming rate in recent years. It is essential for dental professionals to be informed about the physiochemical properties of these drinks and their effects on enamel. The present study measured the fluoride levels, pH, and titratable acidity of multiple popular, commercially available brands of sports and energy drinks. Enamel dissolution was measured as weight loss using an in vitro multiple exposure model consisting of repeated short exposures to these drinks, alternating with exposure to artificial saliva. The relationship between enamel dissolution and fluoride levels, pH, and titratable acidity was also examined. There was a statistically significant difference between the fluoride levels (p = 0.034) and pH (p = 0.04) of the sports and energy drinks studied. The titratable acidity of energy drinks (11.78) was found to be significantly higher than that of sports drinks (3.58) (p < 0.001). Five of the energy drinks (Red Bull Sugar Free, Monster Assault, Von Dutch, Rockstar, and 5-Hour Energy) were found to have the highest titratable acidity values among the brands studied. Enamel weight loss after exposure to energy drinks was significantly higher than it was after exposure to sports drinks. The effect of titratable acidity on enamel weight loss was found to vary inversely with the pH of the drinks. The findings indicated that energy drinks have significantly higher titratable acidity and enamel dissolution associated with them than sports drinks. Enamel weight loss after exposure to energy drinks was more than two times higher than it was after exposure to sports drinks. Titratable acidity is a significant predictor of enamel dissolution, and its effect on enamel weight loss varies inversely with the pH of the drink. The data from the current study can be used to educate patients about the differences between sports and energy drinks and the effects of these drinks on tooth enamel.

Expression of characteristics of ammonium nutrition as affected by pH of the root medium

NASA Technical Reports Server (NTRS)

Chaillou, S.; Vessey, J. K.; Morot-Gaudry, J. F.; Raper, C. D. Jr; Henry, L. T.; Boutin, J. P.

1991-01-01

To study the effect of root-zone pH on characteristic responses of NH4+ -fed plants, soybeans (Glycine max inverted question markL. inverted question mark Merr. cv. Ransom) were grown in flowing solution culture for 21 d on four sources of N (1.0 mol m-3 NO3-, 0.67 mol m-3 NO3- plus 0.33 mol m-3 NH4+, 0.33 mol m-3 NO3- plus 0.67 mol m-3 NH4+, and 1.0 mol m-3 NH4+) with nutrient solutions maintained at pH 6.0, 5.5, 5.0, and 4.5. Amino acid concentration increased in plants grown with NH4+ as the sole source of N at all pH levels. Total amino acid concentration in the roots of NH4+ -fed plants was 8 to 10 times higher than in NO3(-)-fed plants, with asparagine accounting for more than 70% of the total in the roots of these plants. The concentration of soluble carbohydrates in the leaves of NH4+ -fed plants was greater than that of NO3(-)-fed plants, but was lower in roots of NH4+ -fed plants, regardless of pH. Starch concentration was only slightly affected by N source or root-zone pH. At all levels of pH tested, organic acid concentration in leaves was much lower when NH4+ was the sole N source than when all or part of the N was supplied as NO3-. Plants grown with mixed NO3- plus NH4+ N sources were generally intermediate between NO3(-)- and NH4+ -fed plants. Thus, changes in tissue composition characteristic of NH4+ nutrition when root-zone pH was maintained at 4.5 and growth was reduced, still occurred when pH was maintained at 5.0 or above, where growth was not affected. The changes were slightly greater at pH 4.5 than at higher pH levels.

Effects of a bacterial probiotic on ruminal pH and volatile fatty acids during subacute ruminal acidosis (SARA) in cattle.

PubMed

Goto, Hiroko; Qadis, Abdul Qadir; Kim, Yo-Han; Ikuta, Kentaro; Ichijo, Toshihiro; Sato, Shigeru

2016-11-01

Effects of a bacterial probiotic (BP) on ruminal fermentation and plasma metabolites were evaluated in four Holstein cattle (body weight, 645 ± 62 kg; mean ± SD) with induced subacute ruminal acidosis (SARA). SARA was induced by feeding a SARA-inducing diet, and thereafter, 20, 50 or 100 g per head of a commercial BP was administered for 7 consecutive days during the morning feeding. Cattle without BP served as the control. The 24-hr mean ruminal pH in the control was lower, whereas those in the BP groups administered 20 or 50 g were significantly higher compared to the control from days 2 to 7. Circadian patterns of the 1-hr mean ruminal pH were identical (6.4-6.8) among all cattle receiving BP. Although the mean minimum pH in the control on day -7 and day 0 was <5.8, the pH in the treatment groups on day 7 was >5.8 and significantly higher than that of the control group ( >5.2). Ruminal volatile fatty acid (VFA) concentrations were not affected by BP treatment; however, the BP groups had lower lactic acid levels compared with the control group at 20:00 on day 7. Additionally, non-esterified fatty acid levels decreased from 8:00 to 20:00 in all BP groups on day 7. These results suggest that administration of 20 to 50 g of a multi-strain BP for 7 days might improve the low pH and high lactic acid level of the ruminal fluid in SARA cattle.

Quality characteristics of broiler chicken meat from free-range and industrial poultry system for the consumers.

PubMed

da Silva, Débora Cristina Fernandes; de Arruda, Alex Martins Varela; Gonçalves, Alex Augusto

2017-06-01

The aim of this study was to determine and compare the quality parameters of broiler chicken meat from free-range and industrial poultry system. Proximate composition, color, pH, shear force, microbial quality and sensory characteristics were evaluated. Both free-range and industrial chicken meat presented PSE (pale, soft and exudative) anomaly ( L * > 53). An inverse correlation between lightness, pH and shear force was observed. The free range broiler meat had higher yellow color ( b * 11.56) and shear force (2.75 kgf) and lower red color ( a * 1.65) and pH (5.75) in comparison to the industrial broiler meat, due intensive physical activity on growing phase and influence of the pre-slaughter stress on the rigor mortis. The thigh cut from free range broiler meat showed higher protein levels (18.00%), while to the thigh and drumstick cuts of industrial broiler meat showed higher total fat levels (3.4 and 5.0%, respectively). In general, each strain and chickens producing methods gave the peculiar characteristics to meat (chemical, physical, microbiological and sensorial).

Photorespiration and carbon limitation determine productivity in temperate seagrasses.

PubMed

Buapet, Pimchanok; Rasmusson, Lina M; Gullström, Martin; Björk, Mats

2013-01-01

The gross primary productivity of two seagrasses, Zostera marina and Ruppia maritima, and one green macroalga, Ulva intestinalis, was assessed in laboratory and field experiments to determine whether the photorespiratory pathway operates at a substantial level in these macrophytes and to what extent it is enhanced by naturally occurring shifts in dissolved inorganic carbon (DIC) and O2 in dense vegetation. To achieve these conditions in laboratory experiments, seawater was incubated with U. intestinalis in light to obtain a range of higher pH and O2 levels and lower DIC levels. Gross photosynthetic O2 evolution was then measured in this pretreated seawater (pH, 7.8-9.8; high to low DIC:O2 ratio) at both natural and low O2 concentrations (adjusted by N2 bubbling). The presence of photorespiration was indicated by a lower gross O2 evolution rate under natural O2 conditions than when O2 was reduced. In all three macrophytes, gross photosynthetic rates were negatively affected by higher pH and lower DIC. However, while both seagrasses exhibited significant photorespiratory activity at increasing pH values, the macroalga U. intestinalis exhibited no such activity. Rates of seagrass photosynthesis were then assessed in seawater collected from the natural habitats (i.e., shallow bays characterized by high macrophyte cover and by low DIC and high pH during daytime) and compared with open baymouth water conditions (where seawater DIC is in equilibrium with air, normal DIC, and pH). The gross photosynthetic rates of both seagrasses were significantly higher when incubated in the baymouth water, indicating that these grasses can be significantly carbon limited in shallow bays. Photorespiration was also detected in both seagrasses under shallow bay water conditions. Our findings indicate that natural carbon limitations caused by high community photosynthesis can enhance photorespiration and cause a significant decline in seagrass primary production in shallow waters.

Concussive Injuries in Rugby 7s: An American Experience and Current Review.

PubMed

Lopez, Victor; Ma, Richard; Weinstein, Meryle G; Cantu, Robert C; Myers, Laurel S D; Nadkar, Nisha S; Victoria, Christian; Allen, Answorth A

2016-07-01

There is a comparative lack of concussion incidence data on the new Olympic sport Rugby 7s. This study aimed to determine the incidence (number of concussions per 1000 playing hours [ph]), mean and median severity (days absence), and cause of concussive injuries. This is a prospective epidemiology study, amateur to elite/national candidate, male (9768) and female (3876) players in USA Rugby sanctioned tournaments, compliant with the international consensus statement for studies in rugby union. Concussions in US Rugby 7s were 7.7/1000 ph (n = 67). Women encountered concussions at 8.1/1000 ph, and men at 7.6/1000 ph (risk ratio [RR] = 1.10, P = 0.593). Elite/national-level players encountered concussions at higher rates (18.3/1000 ph) than lower levels (6.4/1000 ph; RR = 5.48, P < 0.001). Nonelite backs had higher concussive injury rates compared with forwards (7.7/1000 ph; 3.6/1000 ph; RR = 1.28, P = 0.024). Women missed 36.7 d absence from play, meanwhile men missed 27.9 d (P = 0.245). Retrospective history recall reflected previous concussive injuries occurred in 43% of the current study's cohort; of these, 57% encountered multiple concussions within 1 yr. The incidence of repetitive concussions was not statistically different between genders (RR = 1.09, P = 0.754). Most concussions occurred from tackles (63%) and collisions (24%) (P = 0.056). Sports-related concussions occurred with frequency among US amateur Rugby 7s players. US Elite tournament players sustained concussions at much higher rates than international male Rugby 7s counterparts. A substantial portion of US players who sustained a concussion had previous concussion injuries. Given the high rate of concussion, including repetitive concussive injuries, US Rugby 7s may benefit from concussion prevention measures similar to other contact sports such as instruction on proper tackling techniques, in-game and postgame medical assessment, and a standardized return-to-play protocol.

Crystal structures of different substrates of bacteriorhodopsin's M intermediate at various pH levels.

PubMed

Yamamoto, Masataka; Hayakawa, Naoki; Murakami, Midori; Kouyama, Tsutomu

2009-10-30

The hexagonal P622 crystal of bacteriorhodopsin, which is made up of stacked membranes, is stable provided that the precipitant concentration in the soaking solution is higher than a critical value (i.e., 1.5 M ammonium sulfate). Diffraction data showed that the crystal lattice shrank linearly with increasing precipitant concentration, due primarily to narrowing of intermembrane spaces. Although the crystal shrinkage did not affect the rate of formation of the photoreaction M intermediate, its lifetime increased exponentially with the precipitant concentration. It was suggested that the energetic barrier of the M-to-N transition becomes higher when the motional freedom of the EF loop is reduced by crystal lattice force. As a result of this property, the M state accumulated predominantly when the crystal that was soaked at a high precipitant concentration was illuminated at room temperature. Structural data obtained at various pH levels showed that the overall structure of M is not strongly dependent on pH, except that Glu194 and Glu204 in the proton release complex are more separated at pH 7 than at pH 4.4. This result suggests that light-induced disruption of the paired structure of Glu194 and Glu204 is incomplete when external pH is lower than the pK(a) value of the proton release group in the M state.

Assessment of pH shock as a method for controlling sulfide and methane formation in pressure main sewer systems.

PubMed

Gutierrez, Oriol; Sudarjanto, Gatut; Ren, Guo; Ganigué, Ramon; Jiang, Guangming; Yuan, Zhiguo

2014-01-01

Caustic dosing to raise pH above 10.0 for short periods (hours) is often used by water utilities for controlling sulfide formation in sewers. However the effectiveness of this strategy is rarely reported and the impact of pH level and exposure time on the effectiveness is largely unknown. The effectiveness of this strategy under various pH levels (10.5-12.5) and exposure time (0.5-6.0 h) in controlling sulfide and methane production was evaluated in laboratory scale anaerobic sewer reactors and then in a real sewer system. Laboratory studies showed that the sulfide production rate of the laboratory sewer biofilm was reduced by 70-90% upon the completion of the pH shock, while the methane production rate decreased by 95-100%. It took approximately one week for the sulfate-reducing activity to recover to normal levels. In comparison, the methanogenic activities recovered to only about 10% in 4 weeks. The slow recovery is explained by the substantially loss of cell viability upon pH shocks, which recovered slowly after the shocks. Laboratory studies further revealed that a pH level of 10.5 for 1-2 h represent cost-effective conditions for the pH shock treatment. However, field trials showed a higher pH (11.5) and larger dosing times are needed due to the pH decreases along the sewer line and at the two ends of the caustic-receiving wastewater slugs due to dilution. To have effective sulfide and methane control, it is important to ensure effective conditions (pH > 10.5 and duration >1-2 h) for the entire sewer line. Copyright © 2013 Elsevier Ltd. All rights reserved.

Physiological and biochemical role of the butanediol pathway in Aerobacter (Enterobacter) aerogenes.

PubMed Central

Johansen, L; Bryn, K; Stormer, F C

1975-01-01

Aerobacter (Enterobacter) aerogenes wild type and three mutants deficient in the formation of acetoin and 2,3-butanediol were grown in a glucose minimal medium. Culture densities, pH, and diacetyl, acetoin, and 2,3-butanediol levels were recorded. The pH in wild-type cultures dropped from 7.0 to 5.8, remained constant while acetoin and 2,3-butanediol were formed, and increased to pH 6.5 after exhaustion of the carbon source. More 2,3-butanediol than acetoin was formed initially, but after glucose exhaustion reoxidation to acetoin occurred. The three mutants differed from the wild type in yielding acid cultures (pH below 4.5). The wild type and one of the mutants were grown exponentially under aerobic and anaerobic conditions with the pH fixed at 7.0, 5.8, and 5.0, respectively. Growth rates decreased with decreasing pH values. Aerobically, this effect was weak, and the two strains were affected to the same degree. Under anaerobic conditions, the growth rates were markedly inhibited at a low pH, and the mutant was slightly more affected than the wild type. Levels of alcohol dehydrogenase were low under all conditions, indicating that the enzyme plays no role during exponential growth. The levels of diacetyl (acetoin) reductase, lactate dehydrogenase, and phosphotransacetylase were independent of the pH during aerobic growth of the two strains. Under anaerobic conditions, the formation of diacetyl (acetoin) reductase was pH dependent, with much higher levels of the enzyme at pH 5.0 than at pH 7.0. Lactate dehydrogenase and phosphotransacetylase revealed the same pattern of pH-dependent formation in the mutant, but not in the wild type. PMID:239921

The combination of pH monitoring in the most distal esophagus and symptom association analysis markedly improves the clinical value of esophageal pH tests.

PubMed

Hall, Mats Guerrero Garcia; Wenner, Jörgen; Öberg, Stefan

2016-01-01

The poor sensitivity of esophageal pH monitoring substantially limits the clinical value of the test. The aim of this study was to compare the diagnostic accuracy of esophageal pH monitoring and symptom association analysis performed at the conventional level with that obtained in the most distal esophagus. Eighty-two patients with typical reflux symptoms and 49 asymptomatic subjects underwent dual 48-h pH monitoring with the electrodes positioned immediately above, and 6 cm above the squamo-columnar junction (SCJ). The degree of esophageal acid exposure and the temporal relationship between reflux events and symptoms were evaluated. The sensitivity of pH recording and the diagnostic yield of Symptom Association Probability (SAP) were significantly higher for pH monitoring performed at the distal compared with the conventional level (82% versus 65%, p<0.001 and 74% versus 62%, p<0.001, respectively). The greatest improvement was observed in patients with non-erosive disease. In this group, the sensitivity increased from 46% at the standard level to 66% immediately above the SCJ, and with the combination of a positive SAP as a marker for a positive pH test, the diagnostic yield further increased to 94%. The diagnostic accuracy of esophageal pH monitoring in the most distal esophagus is superior to that performed at the conventional level and it is further improved with the combination of symptom association analysis. PH monitoring with the pH electrode positioned immediately above the SCJ should be introduced in clinical practice and always combined with symptom association analysis.

CD73 and AMPD3 deficiency enhance metabolic performance via erythrocyte ATP that decreases hemoglobin oxygen affinity.

PubMed

O'Brien, William G; Berka, Vladimir; Tsai, Ah-Lim; Zhao, Zhaoyang; Lee, Cheng Chi

2015-08-07

Erythrocytes are the key target in 5'-AMP induced hypometabolism. To understand how regulation of endogenous erythrocyte AMP levels modulates systemic metabolism, we generated mice deficient in both CD73 and AMPD3, the key catabolic enzymes for extracellular and intra-erythrocyte AMP, respectively. Under physiological conditions, these mice displayed enhanced capacity for physical activity accompanied by significantly higher food and oxygen consumption, compared to wild type mice. Erythrocytes from Ampd3(-/-) mice exhibited higher half-saturation pressure of oxygen (p50) and about 3-fold higher levels of ATP and ADP, while they maintained normal 2,3-bisphosphoglycerate (2,3-BPG), methemoglobin levels and intracellular pH. The affinity of mammalian hemoglobin for oxygen is thought to be regulated primarily by 2,3-BPG levels and pH (the Bohr effect). However, our results show that increased endogenous levels of ATP and ADP, but not AMP, directly increase the p50 value of hemoglobin. Additionally, the rise in erythrocyte p50 directly correlates with an enhanced capability of systemic metabolism.

[Relationship between simulated acid rain stress and leaf reflectance].

PubMed

Song, Xiao-dong; Jiang, Hong; Yu, Shu-quan; Zhou, Guo-mo; Jiang, Zi-shan

2010-01-01

Acid rain is a worldwide environmental problem. Serious acid rain pollution in subtropical China has constituted a potential threat to the health of the local forest. In the present paper, the changing properties of the chlorophyll concentration and spectral reflectance at the visible wavelengths for the six subtropical broad-leaved tree species leaves under simulated acid rain (SAR) treatment with different pH levels were studied. With the increasing strength of the SAR, the chlorophyll concentrations of the experimental species under pH 2.5 and pH 4.0 treatment were higher than that under pH 5.6; the spectral reflectance at the visible wavelengths for pH 2.5 and pH 4.0 were lower than that for pH 5.6 in general; while there weren't significant differences between pH 2.5 and pH 4.0. After the treatment with different levels of SAR, the differences in spectral reflectance at the visible wavelengths mainly focused around the green peak and red edge on the reflectance curve. The subtropical broad-leaved tree species studied were relatively not sensitive to acid rain stresses; some stronger acid rain may accelerate the growth of the tree species used here to some extent.

Regulating NETosis: Increasing pH Promotes NADPH Oxidase-Dependent NETosis.

PubMed

Khan, Meraj A; Philip, Lijy M; Cheung, Guillaume; Vadakepeedika, Shawn; Grasemann, Hartmut; Sweezey, Neil; Palaniyar, Nades

2018-01-01

Neutrophils migrating from the blood (pH 7.35-7.45) into the surrounding tissues encounter changes in extracellular pH (pH e ) conditions. Upon activation of NADPH oxidase 2 (Nox), neutrophils generate large amounts of H + ions reducing the intracellular pH (pH i ). Nevertheless, how extracellular pH regulates neutrophil extracellular trap (NET) formation (NETosis) is not clearly established. We hypothesized that increasing pH increases Nox-mediated production of reactive oxygen species (ROS) and neutrophil protease activity, stimulating NETosis. Here, we found that raising pH e (ranging from 6.6 to 7.8; every 0.2 units) increased pH i of both activated and resting neutrophils within 10-20 min (Seminaphtharhodafluor dual fluorescence measurements). Since Nox activity generates H + ions, pH i is lower in neutrophils that are activated compared to resting. We also found that higher pH stimulated Nox-dependent ROS production (R123 generation; flow cytometry, plate reader assay, and imaging) during spontaneous and phorbol myristate acetate-induced NETosis (Sytox Green assays, immunoconfocal microscopy, and quantifying NETs). In neutrophils that are activated and not resting, higher pH stimulated histone H4 cleavage (Western blots) and NETosis. Raising pH increased Escherichia coli lipopolysaccharide-, Pseudomonas aeruginosa (Gram-negative)-, and Staphylococcus aureus (Gram-positive)-induced NETosis. Thus, higher pH e promoted Nox-dependent ROS production, protease activity, and NETosis; lower pH has the opposite effect. These studies provided mechanistic steps of pH e -mediated regulation of Nox-dependent NETosis. Raising pH either by sodium bicarbonate or Tris base (clinically known as Tris hydroxymethyl aminomethane, tromethamine, or THAM) increases NETosis. Each Tris molecule can bind 3H + ions, whereas each bicarbonate HCO3 - ion binds 1H + ion. Therefore, the amount of Tris solution required to cause the same increase in pH level is less than that of equimolar bicarbonate solution. For that reason, regulating NETosis by pH with specific buffers such as THAM could be more effective than bicarbonate in managing NET-related diseases.

Penguins significantly increased phosphine formation and phosphorus contribution in maritime Antarctic soils.

PubMed

Zhu, Renbin; Wang, Qing; Ding, Wei; Wang, Can; Hou, Lijun; Ma, Dawei

2014-11-14

Most studies on phosphorus cycle in the natural environment focused on phosphates, with limited data available for the reduced phosphine (PH3). In this paper, matrix-bound phosphine (MBP), gaseous phosphine fluxes and phosphorus fractions in the soils were investigated from a penguin colony, a seal colony and the adjacent animal-lacking tundra and background sites. The MBP levels (mean 200.3 ng kg(-1)) in penguin colony soils were much higher than those in seal colony soils, animal-lacking tundra soils and the background soils. Field PH3 flux observation and laboratory incubation experiments confirmed that penguin colony soils produced much higher PH3 emissions than seal colony soils and animal-lacking tundra soils. Overall high MBP levels and PH3 emissions were modulated by soil biogeochemical processes associated with penguin activities: sufficient supply of the nutrients phosphorus, nitrogen, and organic carbon from penguin guano, high soil bacterial abundance and phosphatase activity. It was proposed that organic or inorganic phosphorus compounds from penguin guano or seal excreta could be reduced to PH3 in the Antarctic soils through the bacterial activity. Our results indicated that penguin activity significantly increased soil phosphine formation and phosphorus contribution, thus played an important role in phosphorus cycle in terrestrial ecosystems of maritime Antarctica.

Penguins significantly increased phosphine formation and phosphorus contribution in maritime Antarctic soils

PubMed Central

Zhu, Renbin; Wang, Qing; Ding, Wei; Wang, Can; Hou, Lijun; Ma, Dawei

2014-01-01

Most studies on phosphorus cycle in the natural environment focused on phosphates, with limited data available for the reduced phosphine (PH3). In this paper, matrix-bound phosphine (MBP), gaseous phosphine fluxes and phosphorus fractions in the soils were investigated from a penguin colony, a seal colony and the adjacent animal-lacking tundra and background sites. The MBP levels (mean 200.3 ng kg−1) in penguin colony soils were much higher than those in seal colony soils, animal-lacking tundra soils and the background soils. Field PH3 flux observation and laboratory incubation experiments confirmed that penguin colony soils produced much higher PH3 emissions than seal colony soils and animal-lacking tundra soils. Overall high MBP levels and PH3 emissions were modulated by soil biogeochemical processes associated with penguin activities: sufficient supply of the nutrients phosphorus, nitrogen, and organic carbon from penguin guano, high soil bacterial abundance and phosphatase activity. It was proposed that organic or inorganic phosphorus compounds from penguin guano or seal excreta could be reduced to PH3 in the Antarctic soils through the bacterial activity. Our results indicated that penguin activity significantly increased soil phosphine formation and phosphorus contribution, thus played an important role in phosphorus cycle in terrestrial ecosystems of maritime Antarctica. PMID:25394572

Levels of Candidate Periodontal Pathogens in Subgingival Biofilm.

PubMed

Oliveira, R R D S; Fermiano, D; Feres, M; Figueiredo, L C; Teles, F R F; Soares, G M S; Faveri, M

2016-06-01

In recent years, several new periodontal taxa have been associated with the etiology of periodontitis. A recent systematic review provides further support for the pathogenic role of 17 species/phylotypes. Thus, the aim of this study was to assess the prevalence and levels of these species in subjects with generalized chronic periodontitis (GChP; n = 30), generalized aggressive periodontitis (GAgP; n = 30), and periodontal health (PH; n = 30). All subjects underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analyzed for their content of 20 bacterial species/phylotypes through the RNA-oligonucleotide quantification technique. Subjects from the GChP and GAgP groups presented the highest mean values for all clinical parameters in comparison with the PH group (P < 0.05). Subjects with GChP and GAgP showed significantly higher mean levels of Bacteroidetes sp. human oral taxon (HOT) 274, Fretibacterium sp. HOT 360, and TM7 sp. HOT 356 phylotypes, as well as higher mean levels of Filifactor alocis, Fretibacterium fastidiosum, Porphyromonas gingivalis, Tannerella forsythia, and Selenomonas sputigena species than PH subjects (P < 0.05). GAgP subjects presented higher mean levels of TM7 sp. HOT 356 and F. alocis than GChP subjects (P < 0.05). A significantly higher mean prevalence of Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, and Fretibacterium sp. HOT 362 was found in subjects with GChP and GAgP than in PH subjects. Mean levels of P. gingivalis (r = 0.68), T. forsythia (r = 0.62), F. alocis (r = 0.51, P = 0.001), and Fretibacterium sp. HOT 360 (r = 0.41) were correlated with pocket depth (P < 0.001). In conclusion, Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, Fretibacterium sp. HOT 362, and TM7 sp. HOT 356 phylotypes, in addition to F. alocis, F. fastidiosum, and S. sputigena, seem to be associated with periodontitis, and their role in periodontal pathogenesis should be further investigated. © International & American Associations for Dental Research 2016.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, N.S.K.

In aqueous lysine-sucrose model systems, the effects of reaction time, pH and molar ratio were studied on the formation of non-enzymatic browning reaction (NBR) products. The extent of sucrose hydrolysis was measured and the antioxidant effect of NBR products on linoleic acid emulsions was examined. Nuclear magnetic resonance (NMR) spectra were obtained at various stages of browning. Sucrose produced NMR produces with lysine in an aqueous system at 100/sup 0/C. The C-13 NMR spectra indicated that the NBR started when sucrose and lysine were dissolved in water. The C-13 NMR spectra also showed that heating did not have an effectmore » on the gross composition of polymeric species. The absorbance at 480 nm of 0.75 M lysine-sucrose solution heated up to 6 hours increased with reaction times. The pH values of heated lysine-sucrose solution gradually decreased with reaction time. When 0.75 M sucrose or lysine solution was heated separately up to 6 hours, there were no changes in absorbance in pH. In the pH range of 3.52-6.35, higher absorbance was obtained from heated lysine-sucrose solution at acidic pH levels than at neutral pH levels. As the concentration of lysine and sucrose solution was increased, the absorbance increased. At longer reaction times or acidic pH levels, enhanced hydrolysis of sucrose to reducing sugars resulted in more NBR products. NBR products obtained at a longer reaction time, an acidic pH, and higher concentration of reactants showed a darker brown color and were effective in preventing the formation of peroxides. The oxygen uptake of linoleic acid emulsion having NBR products was smaller than that of linoleic acid emulsion without NBR products. Based on these results, it was concluded that sucrose may act as an antioxidant in processed foods containing both amino acids and lipids.« less

Synergistic and Antagonistic Effects of Salinity and pH on Germination in Switchgrass (Panicum virgatum L.)

PubMed Central

Liu, Yuan; Wang, Quanzhen; Zhang, Yunwei; Cui, Jian; Chen, Guo; Xie, Bao; Wu, Chunhui; Liu, Haitao

2014-01-01

The effects of salt-alkaline mixed stress on switchgrass were investigated by evaluating seed germination and the proline, malondialdehyde (MDA) and soluble sugar contents in three switchgrass (Panicum virgatum L.) cultivars in order to identify which can be successfully produced on marginal lands affected by salt-alkaline mixed stress. The experimental conditions consisted of four levels of salinity (10, 60, 110 and 160 mM) and four pH levels (7.1, 8.3, 9.5 and 10.7). The effects of salt-alkaline mixed stress with equivalent coupling of the salinity and pH level on the switchgrass were explored via model analyses. Switchgrass was capable of germinating and surviving well in all treatments under low-alkaline pH (pH≤8.3), regardless of the salinity. However, seed germination and seedling growth were sharply reduced at higher pH values in conjunction with salinity. The salinity and pH had synergetic effects on the germination percentage, germination index, plumular length and the soluble sugar and proline contents in switchgrass. However, these two factors exhibited antagonistic effects on the radicular length of switchgrass. The combined effects of salinity and pH and the interactions between them should be considered when evaluating the strength of salt-alkaline mixed stress. PMID:24454834

Phosphorus doping of Si and Si1 - xGex grown by ultrahigh vacuum chemical vapor deposition using Si2H6 and GeH4

NASA Astrophysics Data System (ADS)

Chen, L. P.; Huang, G. W.; Chang, C. Y.

1996-03-01

100 ppm PH3 diluted in hydrogen is used as the n-type dopant gas in Si and Si1-xGex epilayers grown by ultrahigh vacuum chemical vapor deposition (UHVCVD) using Si2H6 and GeH4. The phosphorus concentration in Si increases linearly at a small PH3 flow rate and becomes nearly saturated at higher flow rates, while the phosphorus concentration in Si1-xGex only shows a nearly linear behavior with PH3 flow rate. The growth rates of Si and Si1-xGex epilayers decrease seriously (˜50%) and slightly (˜10%) with the increase of PH3 flow rate, respectively. These results can be explained by a model based on the enhancement of hydrogen desorption rate at smaller PH3 flow rates and different levels of the effects of phosphorus blocking of surface-activated sites between Si and Si1-xGex epilayers at higher PH3 flow rates.

Who Believes in the Storybook Image of the Scientist?

PubMed

Veldkamp, Coosje L S; Hartgerink, Chris H J; van Assen, Marcel A L M; Wicherts, Jelte M

2017-01-01

Do lay people and scientists themselves recognize that scientists are human and therefore prone to human fallibilities such as error, bias, and even dishonesty? In a series of three experimental studies and one correlational study (total N = 3,278) we found that the "storybook image of the scientist" is pervasive: American lay people and scientists from over 60 countries attributed considerably more objectivity, rationality, open-mindedness, intelligence, integrity, and communality to scientists than to other highly-educated people. Moreover, scientists perceived even larger differences than lay people did. Some groups of scientists also differentiated between different categories of scientists: established scientists attributed higher levels of the scientific traits to established scientists than to early-career scientists and Ph.D. students, and higher levels to Ph.D. students than to early-career scientists. Female scientists attributed considerably higher levels of the scientific traits to female scientists than to male scientists. A strong belief in the storybook image and the (human) tendency to attribute higher levels of desirable traits to people in one's own group than to people in other groups may decrease scientists' willingness to adopt recently proposed practices to reduce error, bias and dishonesty in science.

Who Believes in the Storybook Image of the Scientist?

PubMed Central

Veldkamp, Coosje L. S.; Hartgerink, Chris H. J.; van Assen, Marcel A. L. M.; Wicherts, Jelte M.

2017-01-01

ABSTRACT Do lay people and scientists themselves recognize that scientists are human and therefore prone to human fallibilities such as error, bias, and even dishonesty? In a series of three experimental studies and one correlational study (total N = 3,278) we found that the “storybook image of the scientist” is pervasive: American lay people and scientists from over 60 countries attributed considerably more objectivity, rationality, open-mindedness, intelligence, integrity, and communality to scientists than to other highly-educated people. Moreover, scientists perceived even larger differences than lay people did. Some groups of scientists also differentiated between different categories of scientists: established scientists attributed higher levels of the scientific traits to established scientists than to early-career scientists and Ph.D. students, and higher levels to Ph.D. students than to early-career scientists. Female scientists attributed considerably higher levels of the scientific traits to female scientists than to male scientists. A strong belief in the storybook image and the (human) tendency to attribute higher levels of desirable traits to people in one’s own group than to people in other groups may decrease scientists’ willingness to adopt recently proposed practices to reduce error, bias and dishonesty in science. PMID:28001440

Candida Carriage Rate and Growth Characteristics of Saliva in Diabetes Mellitus Patients: A Case-Control Study.

PubMed

Balan, Preethi; B Gogineni, Subhas; Kumari N, Sucheta; Shetty, Veena; Lakshman Rangare, Anusha; L Castelino, Renita; Areekat K, Fazil

2015-01-01

Background and aims. The aim of this study was to establish a relationship between salivary glucose levels and Candida carriage rate in type 2 diabetes mellitus patients and assess the growth characteristics and acid production of Candida in glucose-supplemented saliva. Materials and methods . A total of 90 subjects, 30 with controlled type 2 diabetes, 30 with uncontrolled type 2 diabetes and 30 without diabetes (control subjects), aged 30‒60 years, participated in the study. Unstimulated saliva was collected and investigated for glucose levels (GOD-POD method), colony-forming units (CFU) of Candida and salivary pH, using Indikrom paper strips). Analysis of statistical significance of salivary glucose and PH levels was carried out using post hoc Tukey HSD test. Correlation of Candida carriage rate with salivary glucose and salivary PH in the study groups and control group was made using Pearson's correlation. Results. Candida CFUs were significantly higher in diabetic subjects, with a significant and positive correlation with salivary glucose levels. There was a negative correlation between salivary PH levels and Candida carriage rate. Conclusion. Increased salivary glucose was associated with increased prevalence of oral Candida in diabetic subjects. The growth of Candida in saliva was accompanied by a rapid decline in PH, which in turn favored their growth.

Prolonged maintenance of 2,3-diphosphoglycerate acid and adenosine triphosphate in red blood cells during storage.

PubMed

de Korte, Dirk; Kleine, Mya; Korsten, Herbert G H; Verhoeven, Arthur J

2008-06-01

Current additive solutions (ASs) for red cells (RBCs) do not maintain a constant level of critical metabolites such as adenosine triphosphate (ATP) and 2,3-diphosphoglycerate acid (2,3-DPG) during cold storage. From the literature it is known that the intracellular pH is an important determinant of RBC metabolism. Therefore, a new, alkaline, AS was developed with the aim to allow cold storage of RBCs with stable product characteristics. Whole blood-derived RBCs (leukoreduced) were resuspended in experimental medium phosphate-adenine-guanosine-glucose-gluconate-mannitol (PAGGG-M; pH 8.2) with and without washing in the same medium. During cold storage several in vitro variables, such as intracellular pH, 2,3-DPG, ATP, and hemolysis, were analyzed. During cold storage, RBCs resuspended in PAGGG-M showed a constant ATP level (approx. 6 mumol/g Hb) and a very limited hemolysis (<0.2%). The 2,3-DPG content showed an increase until Day 21 (150% of initial level), followed by a slow decrease, with at Day 35 still 100 percent of the initial level. RBCs washed in PAGGG-M even showed a continuous increase of 2,3-DPG during 35 days, with a maximum level of 200 percent of the initial value. The effect of PAGGG-M appears to be related to long-lasting effects of the initial intracellular pH shortly after production. Resuspension of RBCs in our alkaline medium PAGGG-M resulted in a RBC unit of high quality during storage for up to at least 35 days, with 2,3-DPG levels of higher than 10 mumol per g Hb, hemolysis of less than 0.2 percent, and ATP levels of higher than 5 mumol per g Hb.

Effect of root canal obturation with calcium silicate materials on pH change in simulated root resorption defects.

PubMed

Aggarwal, Vivek; Singla, Mamta; Miglani, Sanjay; Sharma, Ritu

2018-01-01

This study evaluated the effect of 3 commercially available calcium silicate materials (CSMs) on pH changes in simulated root resorption defects. Simulated root resorption defects were prepared on the facial root surface of 40 mandibular premolars. The depth of each defect was individually calculated to standardize the remaining dentin thickness to 1 mm. Prepared canals were obturated with the 3 CSMs. Ten specimens were kept as controls, filled with unbuffered normal saline. The pH measurements were taken at 1 hour, 6 hours, 1 day, 1 week, 2 weeks, 3 weeks, 1 month, and 2 months. All CSM groups exhibited an initial alkaline pH of 9.0-9.7. The pH decreased to 8.0-8.5 after 2 months of storage. There were no significant differences between pH measurements at other time intervals. The CSM groups exhibited higher pH levels than the control group. The results showed that intracanal placement of the CSMs maintained initial pH levels of 9.0-9.7 inside the simulated resorption defects; these measurements gradually decreased to 8.0-8.5 over the span of 2 months.

The correlation between dental calculus and disturbed mineral metabolism in paediatric patients with chronic kidney disease.

PubMed

Davidovich, Esti; Davidovits, Miriam; Peretz, Benny; Shapira, Joseph; Aframian, Doron J

2009-08-01

Vascular calcifications have been documented in children with end-stage renal disease. However, only a few reports have described abundant dental calculus formation in children suffering from chronic kidney disease (CKD). Moreover, dental calculus scores (DCS) and their correlation with renal disease severity have not been studied. DCS in 74 young CKD patients were evaluated: 25 pre-dialytic (PrD), 18 on dialysis (D) and 31 with transplants (T) compared to 32 healthy participants (C). Saliva and serum analysis included creatinine (Cr), urea (U), calcium (Ca), phosphorous (P), magnesium (Mg) as well as intraoral pH levels. All patient groups presented high DCS. DCS and pH levels were higher in the D group with a positive correlation between pH and lower incisor DCS (r = 0.56, P = 0.017). The highest salivary Ca was found in the PrD group. Salivary P in the PrD group was found to be higher than in the T and C groups. The lowest salivary Mg was found in the D group while the highest salivary Ca x P product was found in the PrD group. In all patient groups, salivary U was higher than in the C group with a 2.5-fold increase in the D group. Salivary Cr resembled the U salivary concentrations. Alterations in salivary Ca, P, Mg, U, Cr and intraoral pH levels were observed in the patient groups. DCS correlated with renal disease severity and therefore may be a reflection of other tissue calcification pathologies found in these patients.

Effects of soil characteristics on grape juice nutrient concentrations and other grape quality parameters in Shiraz

NASA Astrophysics Data System (ADS)

Concepción Ramos, Maria; Romero, Maria Paz

2017-04-01

This study investigated the response of grapes to soil properties in the variety Shiraz (SH) cultivated in the Costers de Segre Designation of Origin (NE, Spain). The research was carried out in two areas with differences in vigor, which was examined using the Normalized Difference Vegetation Index (NDVI). Soil properties such as organic matter content, pH, electrical conductivity and nutrients (N, P, K, Ca, Mg, Cu, Zn and Mn) were analysed in the two areas. Soil analyses were limited to the upper 40 cm. Soil N-NO3 was measured in 2M KCl extracts. Assimilable phosphorus was analysed by extraction with 0.5 M NaHCO3 at pH 8.5 using the Olsen method. The available K, Ca and Mg were evaluated in hemaaxinecobalt trichloride extracts and the available fraction of Cu, Zn, Mn and Fe in DTPA- trietanolamine extracts, by spectroscopy atomic emission/absorption. Berry grapes were collected at maturity. Nutrients in grape juice (K, Ca, Mg Cu, Zn, Mn and Fe) were determined after a microwave hydrogen peroxide digestion in a closed vessel microwave digestion system and measured by spectroscopy. Other grape properties that determine grape quality such as pH, berry weight and sugar content were analysed using the methods proposed by the OIV. Differences in soil properties were observed between plots, which determined the differences in vigour. The vines with lower vigour were grown in the soils with higher pH, electrical conductivity and silt content, which had in addition higher Ca, Mg and K available levels as well as higher levels of Fe and Mn than the soil in which vines had higher vigour. However, the available fraction of Cu and Zn was smaller. Similar differences in nutrient concentration in the berry were observed for all nutrients except for Cu. Grape juice pH and total soluble solids (°Brix) were higher in the most vigorous vines. However, the differences in berry weight and total acidity at ripening were not significant. Keywords: acidity; berry weight; nutrients; pH; soil characteristics, sugar content.

Effects of a bacterial probiotic on ruminal pH and volatile fatty acids during subacute ruminal acidosis (SARA) in cattle

PubMed Central

GOTO, Hiroko; QADIS, Abdul Qadir; KIM, Yo-Han; IKUTA, Kentaro; ICHIJO, Toshihiro; SATO, Shigeru

2016-01-01

Effects of a bacterial probiotic (BP) on ruminal fermentation and plasma metabolites were evaluated in four Holstein cattle (body weight, 645 ± 62 kg; mean ± SD) with induced subacute ruminal acidosis (SARA). SARA was induced by feeding a SARA-inducing diet, and thereafter, 20, 50 or 100 g per head of a commercial BP was administered for 7 consecutive days during the morning feeding. Cattle without BP served as the control. The 24-hr mean ruminal pH in the control was lower, whereas those in the BP groups administered 20 or 50 g were significantly higher compared to the control from days 2 to 7. Circadian patterns of the 1-hr mean ruminal pH were identical (6.4–6.8) among all cattle receiving BP. Although the mean minimum pH in the control on day –7 and day 0 was <5.8, the pH in the treatment groups on day 7 was >5.8 and significantly higher than that of the control group ( >5.2). Ruminal volatile fatty acid (VFA) concentrations were not affected by BP treatment; however, the BP groups had lower lactic acid levels compared with the control group at 20:00 on day 7. Additionally, non-esterified fatty acid levels decreased from 8:00 to 20:00 in all BP groups on day 7. These results suggest that administration of 20 to 50 g of a multi-strain BP for 7 days might improve the low pH and high lactic acid level of the ruminal fluid in SARA cattle. PMID:27430197

Measures for Ph.D. Evaluation: The Recruitment Process

ERIC Educational Resources Information Center

D'Agostino, Antonella; Fruzzetti, Stefania; Ghellini, Giulio; Neri, Laura

2011-01-01

In the last years the quality of Higher Education (HE) system and its evaluation have been key issues of the political and scientific debate on education policies all over Europe. In the wide landscape that involves the entire HE system we draw attention on the third level of its organization, i.e. the Ph.D. In particular, this paper discusses the…

Effect of ripening stage on the development of the microbial community during spontaneous fermentation of green tomatoes.

PubMed

Paramithiotis, Spiros; Kouretas, Konstantinos; Drosinos, Eleftherios H

2014-06-01

Spontaneous fermentation of plant-derived material is mainly performed on a small scale, with the exception of fermented olives, cucumbers, sauerkraut and kimchi, which have met worldwide commercial significance. This study of spontaneous fermentation of green tomatoes at different stages of ripening revealed a significant effect on the growth kinetics of lactic acid bacteria and the final pH value. Leuconostoc mesenteroides dominated spontaneous fermentation when the initial pH value ranged from 3.8 to 4.8 whereas at higher pH values (4.9-5.4) it co-dominated with Leu. citreum and Lactobacillus casei. Application of RAPD-PCR and rep-PCR allowed differentiation at sub-species level, suggesting a microbial succession at that level accompanying the respective at species level. Ripening stage affected the development of the micro-ecosystem through the growth of lactic acid bacteria and concomitant pH value reduction; however, the outcome of the fermentation was only marginally different. © 2013 Society of Chemical Industry.

Influence of turkey meat on residual nitrite in cured meat products.

PubMed

Kilic, B; Cassens, R G; Borchert, L L

2001-02-01

A response surface experimental design was employed to estimate residual nitrite level at various initial nitrite concentrations, percent turkey meat in the formula, and heat quantity (F) values using a typical wiener as the test system. Pork and mechanically separated turkey were used as the meat ingredients. Residual nitrite and pH were measured at day 1, 7 days, 14 days, and 49 days after processing. Protein, fat, salt, moisture, and CIE (L*a*b*) color values were also determined. Results showed that the effect of turkey meat on residual nitrite level was significant (P < 0.01). An increased amount of turkey meat in the formula resulted in lower residual nitrite levels at a fixed pH. The residual nitrite level was initially proportional to initial nitrite concentration, but it became a nonsignificant factor during longer storage time. Differences in heat quantity had a significant effect (P < 0.05) on residual nitrite level initially. Greater heat quantity decreased residual nitrite level in finished cured meat products at a fixed pH. However, this effect became nonsignificant during longer storage. Reduction of residual nitrite in wieners because of turkey meat addition at a fixed pH was due to characteristics of the turkey tissue, but the mechanism of action remains unknown. It was also established that commercial wieners had a higher pH if poultry meat was included in the formulation.

Water chemistry and its effects on the physiology and survival of Atlantic salmon Salmo salar smolts

USGS Publications Warehouse

Liebich, T.; McCormick, S.D.; Kircheis, D.; Johnson, Kevin; Regal, R.; Hrabik, T.

2011-01-01

The physiological effects of episodic pH fluctuations on Atlantic salmon Salmo salar smolts in eastern Maine, U.S.A., were investigated. During this study, S. salar smolts were exposed to ambient stream-water chemistry conditions at nine sites in four catchments for 3 and 6 day intervals during the spring S. salar smolt migration period. Plasma chloride, plasma glucose, gill aluminium and gill Na+- and K+-ATPase levels in S. salar smolts were assessed in relation to ambient stream-water chemistry during this migration period. Changes in both plasma chloride and plasma glucose levels of S. salar smolts were strongly correlated with stream pH, and S. salar smolt mortality occurred in one study site with ambient stream pH between 5??6 and 5??8 during the study period. The findings from this study suggest that physiological effects on S. salar smolts are strongly correlated with stream pH and that in rivers and streams with low dissolved organic carbon (DOC) concentrations the threshold for physiological effects and mortality probably occurs at a higher pH and shorter exposure period than in rivers with higher DOC. Additionally, whenever an acidification event in which pH drops below 5??9 coincides with S. salar smolt migration in eastern Maine rivers, there is potential for a significant reduction in plasma ions of S. salar smolts. ?? 2011 The Fisheries Society of the British Isles.

Effects of inclusion levels of banana (Musa spp.) peelings on feed degradability and rumen environment of cattle fed basal elephant grass.

PubMed

Nambi-Kasozi, Justine; Sabiiti, Elly Nyambobo; Bareeba, Felix Budara; Sporndly, Eva; Kabi, Fred

2016-04-01

The effect of feeding varying banana peeling (BP) levels on rumen environment and feed degradation characteristics was evaluated using three rumen fistulated steers in four treatments. The steers were fed BP at 0, 20, 40, and 60% levels of the daily ration with basal elephant grass (EG) to constitute four diets. Maize bran, cotton seed cake, and Gliricidia sepium were offered to make the diets iso-nitrogenous. The nylon bag technique was used to measure BP and EG dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) degradabilities at 0, 6, 12, 24, 48, 72, 96, and 120 h. Rumen fluid samples were collected to determine pH and volatile fatty acid (VFA) concentrations. Effective DM, CP, and NDF degradabilities of BP ranged between 574 and 807, 629-802, and 527-689 g/kg, respectively, being lower at higher BP levels. Elephant grass degradability behaved similarly with relatively high effective CP degradability (548-569 g/kg) but low effective DM and NDF degradability (381-403 and 336-373 g/kg, respectively). Rumen pH and VFA reduced with increasing BP in the diets. Rumen pH dropped to 5.8 and 5.9 at the 40 and 60% BP feeding levels, respectively. Banana peelings were better degraded than EG but higher BP levels negatively affected feed degradability and rumen environment.

Vitamin D status, body composition and hypertensive target organ damage in primary hypertension.

PubMed

Pludowski, Pawel; Jaworski, Maciej; Niemirska, Anna; Litwin, Mieczyslaw; Szalecki, Mieczyslaw; Karczmarewicz, Elżbieta; Michalkiewicz, Jacek

2014-10-01

Overweight/obesity and high blood pressure during growth period are important risk factors of cardiovascular disease later in life. Cardiovascular system, fat and muscles are among target tissues for vitamin D and low 25(OH)D levels are likely to attenuate potential benefits of its action. The study was aimed to evaluate vitamin D status and body composition in children and adolescents with primary hypertension (PH). The study population comprised 78 patients aged 15.4±2.3yrs (9-18yrs; 15 girls) with diagnosed PH. Total 25(OH)D and parathyroid hormone (PTH) were assayed by Cobas e411 machine (Roche Diagnostics). DXA (Prodigy, GE Lunar) was used to assess total body bone mineral content (TBBMC; g), total body bone mineral density (TBBMD; g/cm(2)), lean body mass (LBM; g), % lean body mass (%LBM), fat mass (FM; g), % fat mass (% FM), Android %Fat, Gynoid %Fat and Trunk fat mass (Trunk FM; g). Hypertensive cases (BMI=25.6±4.2kg/m(2)), compared to reference, had slightly increased TBBMD and TBBMC Z-scores (+0.40±0.91 and +0.59±0.96; both p<0.001), and had markedly increased FM and FM/body weight ratio Z-scores of ±1.83±1.63 (p<0.0001) and +1.43±1.05 (p<0.0001). LBM Z-scores were slightly increased as well (+0.34±1.08, p<0.001). In contrast, markedly reduced LBM/body weight ratio Z-scores of -1.47±0.90 (p<0.0001) and disturbed relationship between FM and LBM as assessed by FM/LBM ratio Z-score of +1.53±1.29 (p<0.0001) were noted. The average serum levels of 25(OH)D of 17.8±6.9ng/mL and PTH of 34.8±16.8pg/mL were noted in PH group. 91% PH cases showed 25(OH)D levels lower than 30ng/mL. 71% of PH subjects revealed vitamin D deficiency (25(OH)D<20ng/ml). 10% of PH cases showed 25(OH)D levels lower than 10ng/mL. 25(OH)D levels negatively correlated with PTH showing r=-0.24 (p=0.03). Absolute LBM/body weight ratio values positively correlated with 25(OH)D levels (r=0.31; p=0.01). In contrast, absolute FM/body weight ratio values correlated negatively with 25(OH)D levels (r=-0.32; p<0.01). Moreover, 25(OH)D levels negatively correlated with absolute Trunk FM (r=-0.29; p<0.05), Android %Fat (r=-0.32; p<0.01) and with Gynoid %Fat (r=-0.28; p<0.05). PTH and 25(OH)D concentrations did not differ when severity of hypertension, left ventricular mass and carotid intima-media thickness were controlled for. Concluding, higher muscle mass stores in body weight coincided with higher 25(OH)D levels. Higher fat mass stores coincided with lower 25(OH)D levels in PH group. Whether vitamin D insufficiency/deficiency in PH group should be considered as a cause of disease or epiphenomenon remains unknown. This article is part of a Special Issue entitled '16th Vitamin D Workshop'. Copyright © 2013. Published by Elsevier Ltd.

Neutralisation of an acidic pit lake by alkaline waste products.

PubMed

Allard, Bert; Bäckström, Mattias; Karlsson, Stefan; Grawunder, Anja

2014-01-01

A former open pit where black shale (alum shale) was excavated during 1942-1965 has been water filled since 1966. The water chemistry was dominated by calcium and sulphate and had a pH of 3.2-3.4 until 1997-1998, when pH was gradually increasing. This was due to the intrusion of leachates from alkaline cement waste deposited close to the lake. A stable pH of around 7.5 was obtained after 6-7 years. The chemistry of the pit lake has changed due to the neutralisation. Concentrations of some dissolved metals, notably zinc and nickel, have gone down, as a result of adsorption/co-precipitation on solid phases (most likely iron and aluminium hydroxides), while other metals, notably uranium and molybdenum, are present at elevated levels. Uranium concentration is reaching a minimum of around pH 6.5 and is increasing at higher pH, which may indicate a formation of neutral and anionic uranyl carbonate species at high pH (and total carbonate levels around 1 mM). Weathering of the water-exposed shale is still in progress.

Effects of salt concentration and pH on structural and functional properties of Lactobacillus acidophilus: FT-IR spectroscopic analysis.

PubMed

Gandhi, Akanksha; Shah, Nagendra P

2014-03-03

The effects of sodium chloride concentration and varying pH levels on the structural and functional properties of Lactobacillus acidophilus were investigated. Reconstituted skim milk was inoculated with Lb. acidophilus at varying salt concentrations (0, 1, 2, 5 and 10% NaCl) and pH levels (4.0, 5.0 and 6.0) and ACE-inhibitory activity and proteolytic activity were determined and the viable cell count was enumerated after 24h of fermentation at 37 °C. The degree of proteolysis exhibited an increase with higher salt concentration at pH 5.0 and 6.0. ACE-inhibitory activity was found to be the highest at pH 5.0 at all salt concentrations. Fourier transform infrared spectroscopy results demonstrated significant changes occurring beyond 2% NaCl particularly at low pH (4.0). The findings revealed that significant changes occurred in amide I and amide III regions when Lb. acidophilus was subjected to varying salt concentrations. Copyright © 2014 Elsevier B.V. All rights reserved.

Association of three putative periodontal pathogens with chronic periodontitis in Brazilian subjects

PubMed Central

GONÇALVES, Cristiane; SOARES, Geisla Mary S.; FAVERI, Marcelo; PÉREZ-CHAPARRO, Paula Juliana; LOBÃO, Eduardo; FIGUEIREDO, Luciene Cristina; BACCELLI, Gustavo Titonele; FERES, Magda

2016-01-01

ABSTRACT Objective The aim of this study was to evaluate the association of Porphyromonas endodontalis, Filifactor alocis and Dialister pneumosintes with the occurrence of periodontitis. Material and Methods Thirty subjects with chronic periodontitis (ChP) and 10 with periodontal health (PH) were included in the study. Nine subgingival biofilm samples were collected as follows: i) PH group - from the mesial/buccal aspect of each tooth in two randomly chosen contralateral quadrants; ii) ChP group - from three sites in each of the following probing depth (PD) categories: shallow (≤3 mm), moderate (4-6 mm) and deep (≥7 mm). Checkerboard DNA-DNA hybridization was used to analyze the samples. Results We found the three species evaluated in a higher percentage of sites and at higher levels in the group with ChP than in the PH group (p<0.05, Mann-Whitney test). We also observed these differences when the samples from sites with PD≤4 mm or ≥5 mm of subjects with ChP were compared with those from subjects with PH (p<0.05, Mann-Whitney test). In addition, the prevalence and levels of D. pneumosintes, and especially of F. alocis were very low in healthy subjects (0.12x105 and 0.01x105, respectively). Conclusion F. alocis and D. pneumosintes might be associated with the etiology of ChP, and their role in the onset and progression of this infection should be further investigated. The role of P. endodontalis was less evident, since this species was found in relatively high levels and prevalence in the PH group. PMID:27119767

Association of three putative periodontal pathogens with chronic periodontitis in Brazilian subjects.

PubMed

Gonçalves, Cristiane; Soares, Geisla Mary S; Faveri, Marcelo; Pérez-Chaparro, Paula Juliana; Lobão, Eduardo; Figueiredo, Luciene Cristina; Baccelli, Gustavo Titonele; Feres, Magda

2016-04-01

Objective The aim of this study was to evaluate the association of Porphyromonas endodontalis, Filifactor alocis and Dialister pneumosintes with the occurrence of periodontitis. Material and Methods Thirty subjects with chronic periodontitis (ChP) and 10 with periodontal health (PH) were included in the study. Nine subgingival biofilm samples were collected as follows: i) PH group - from the mesial/buccal aspect of each tooth in two randomly chosen contralateral quadrants; ii) ChP group - from three sites in each of the following probing depth (PD) categories: shallow (≤3 mm), moderate (4-6 mm) and deep (≥7 mm). Checkerboard DNA-DNA hybridization was used to analyze the samples. Results We found the three species evaluated in a higher percentage of sites and at higher levels in the group with ChP than in the PH group (p<0.05, Mann-Whitney test). We also observed these differences when the samples from sites with PD≤4 mm or ≥5 mm of subjects with ChP were compared with those from subjects with PH (p<0.05, Mann-Whitney test). In addition, the prevalence and levels of D. pneumosintes, and especially of F. alocis were very low in healthy subjects (0.12x105 and 0.01x105, respectively). Conclusion F. alocis and D. pneumosintes might be associated with the etiology of ChP, and their role in the onset and progression of this infection should be further investigated. The role of P. endodontalis was less evident, since this species was found in relatively high levels and prevalence in the PH group.

Oxidative stability of egg and soy lecithin as affected by transition metal ions and pH in emulsion.

PubMed

Wang, Guang; Wang, Tong

2008-12-10

Oxidative stability of egg and soy lecithin in emulsion was evaluated with two transition metal ions, cupric and ferric ion, at two concentration levels (50 and 500 microM). The effect of pH on lipid oxidation was also examined under these two concentrations for each ion. Egg lecithin (EL) had similar peroxide value (PV) development pattern as soy lecithin (SL) when treated with cupric ion under both acidic and neutral pH. Acidic pH of 3 accelerated oxidation of both EL and SL, especially under high concentration of copper. When treated with ferric ion, EL oxidized much faster than SL did. EL had higher value of thiobarbituric acid-reactive substances (TBARS) than SL, possibly because of its higher content of long-chain polyunsaturated fatty acids (PUFA). Acidic pH accelerated TBARS development for both EL and SL, but EL had more significantly increased values. Cupric ion was more powerful than ferric in catalyzing oxidation of both EL and SL under both acidic and neutral pH conditions as measured by PV and TBARS. Linoleic acid may contribute to higher PV production, however, arachidonic acid and docosahexaenoic acid may have contributed more to TBARS production. Overall, SL showed better oxidative stability than EL under the experimental conditions. This study also suggests that using multiple methods is necessary in properly evaluating lipid oxidative stability.

Metabolic Microenvironmental Control by Photosynthetic Biofilms under Changing Macroenvironmental Temperature and pH Conditions▿ †

PubMed Central

Bissett, Andrew; Reimer, Andreas; de Beer, Dirk; Shiraishi, Fumito; Arp, Gernot

2008-01-01

Ex situ microelectrode experiments, using cyanobacterial biofilms from karst water creeks, were conducted under various pH, temperature, and constant-alkalinity conditions to investigate the effects of changing environmental parameters on cyanobacterial photosynthesis-induced calcification. Microenvironmental chemical conditions around calcifying sites were controlled by metabolic activity over a wide range of photosynthesis and respiration rates, with little influence from overlying water conditions. Regardless of overlying water pH levels (from 7.8 to 8.9), pH at the biofilm surface was approximately 9.4 in the light and 7.8 in the dark. The same trend was observed at various temperatures (4°C and 17°C). Biological processes control the calcium carbonate saturation state (Ω) in these and similar systems and are able to maintain Ω at approximately constant levels over relatively wide environmental fluctuations. Temperature did, however, have an effect on calcification rate. Calcium flux in this system is limited by its diffusion coefficient, resulting in a higher calcium flux (calcification and dissolution) at higher temperatures, despite the constant, biologically mediated pH. The ability of biological systems to mitigate the effects of environmental perturbation is an important factor that must be considered when attempting to predict the effects of increased atmospheric partial CO2 pressure on processes such as calcification and in interpreting microfossils in the fossil record. PMID:18689512

Factors Affecting the Levels of Heavy Metals in Juices Processed with Filter Aids.

PubMed

Wang, Zhengfang; Jackson, Lauren S; Jablonski, Joseph E

2017-06-01

This study investigated factors that may contribute to the presence of arsenic and other heavy metals in apple and grape juices processed with filter aids. Different types and grades of filter aids were analyzed for arsenic, lead, and cadmium with inductively coupled plasma-tandem mass spectrometry. Potential factors affecting the transfer of heavy metals to juices during filtration treatments were evaluated. Effects of washing treatments on removal of heavy metals from filter aids were also determined. Results showed that diatomaceous earth (DE) generally contained a higher level of arsenic than perlite, whereas perlite had a higher lead content than DE. Cellulose contained the lowest level of arsenic among the surveyed filter aids. All samples of food-grade filter aids contained arsenic and lead levels that were below the U.S. Pharmacopeia and National Formulary limits of 10 ppm of total leachable arsenic and lead for food-grade DE filter aids. Two samples of arsenic-rich (>3 ppm) food-grade filter aids raised the level of arsenic in apple and grape juices during laboratory-scale filtration treatments, whereas three samples of low-arsenic (<1 ppm) food-grade filter aids did not affect arsenic levels in filtered juices. Filtration tests with simulated juices (pH 2.9 to 4.1, Brix [°Bx] 8.2 to 18.1, total suspended solids [TSS] 0.1 to 0.5%) showed that pH or sugar content had no effect on arsenic levels of filtered juices, whereas arsenic content of filtered juice was elevated when higher amounts of filter aid were used for filtration. Authentic unfiltered apple juice (pH 3.6, °Bx 12.9, TSS 0.4%) and grape juice (pH 3.3, °Bx 16.2, TSS 0.05%) were used to verify results obtained with simulated juices. However, body feed ratio did not affect the arsenic content of filtered authentic juices. Washing treatments were effective at reducing arsenic, but not cadmium or lead, concentrations in a DE filter aid. This study identified ways to reduce the amount of arsenic transferred to juices during filtration.

Calcium Hypochlorite Solutions: Evaluation of Surface Tension and Effect of Different Storage Conditions and Time Periods over pH and Available Chlorine Content.

PubMed

Leonardo, Natália Gomes e Silva; Carlotto, Israel Bangel; Luisi, Simone Bonato; Kopper, Patrícia Maria Poli; Grecca, Fabiana Soares; Montagner, Francisco

2016-04-01

The aim of this study was to evaluate the pH and the available chlorine content from sodium hypochlorite (NaOCl) and calcium hypochlorite (Ca[OCl]2) solutions stored in different conditions and time periods and the surface tension of Ca(OCl)2 solutions in comparison with NaOCl. Solutions at 0.5%, 1%, 2.5%, and 5.25% concentrations were prepared. The pH level and the available chlorine content of freshly prepared solutions and solutions stored for 30, 60, and 90 days at 25°C, 4°C, or 37°C were evaluated in a digital pH meter and by titration, respectively. Surface tension was tested using a Du Nouy tensiometer (Sigma 702, Force Tensiometer; Attension, Espoo, Finland). Descriptive and inferential statistical analyses were performed. A precipitate formed by 2.5% and 5.25% Ca(OCl)2 solutions was observed. Ca(OCl)2 showed a higher concentration of available chlorine than NaOCl. Both 2.5% and 5.25% NaOCl and Ca(OCl)2 had a decrease in the available chlorine content when compared with freshly prepared solutions; 0.5% and 1% NaOCl tend to have a lower pH compared with 0.5% and 1% Ca(OCl)2. NaOCl, 5.25%, showed higher pH compared with 5.25% Ca(OCl)2. NaOCl and Ca(OCl)2 in 0.5% and 1% concentrations tend to show a reduced pH level, whereas 2.5% and 5.25% solutions showed an increase in pH. The heat contributed to the instability of the solutions. NaOCl showed lower surface tension values than Ca(OCl)2. Ca(OCl)2 solutions are extremely alkaline and tend to have more available chlorine content than NaOCl but have a higher surface tension than NaOCl. Regarding the available chlorine content, these solutions tend to be stable to 30 days of storage when kept at 4°C or at 25°C. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Hypoglycemia Prevents Increase in Lactic Acidosis During Reperfusion After Temporary Cerebral Ischemia in Rats

PubMed Central

Sappey-Marinier, Dominique; Chileuitt, Laureano; Weiner, Michael W.; Faden, Alan I.; Weinstein, Philip R.

2009-01-01

Sequential 31P and 1H MRS was used to measure cerebral phosphate metabolites, intracellular pH, and lactate in normoglycemic and hypoglycemic rats during 30 min of complete cerebral ischemia and 5.5 h of reperfusion. These results were correlated with brain levels of free fatty acids (FFAs), excitatory amino acids, cations, and water content at death. The lactate/N-acetyl aspartate ratio was not significantly different between groups before or during occlusion. During reperfusion, the ratio was higher in normoglycemic rats from 3 to 85 min (p≤ 0.05), and recovery time was faster in hypoglycemic rats (29 vs 45 min; p = 0.04), suggesting reduced lactate production and faster recovery of aerobic metabolism. During occlusion, significant but comparable decrease of intracellular pH occurred in each group. Intracellular pH was higher in hypoglycemic rats at 140 min and 260 min of reperfusion. Water content, Na and K+ concentrations, and FFA and excitatory amino acid levels were not significantly different between groups, but hypoglycemic rats had less depletion of levels of Mg2+ (p=0.011). These results show that hypoglycemia has a limited but potentially beneficial effect on postischemic lactic acidosis. PMID:8771092

Association of salivary calcium, phosphate, pH and flow rate on oral health: A study on 90 subjects.

PubMed

Fiyaz, Mohamed; Ramesh, Amitha; Ramalingam, Karthikeyan; Thomas, Biju; Shetty, Sucheta; Prakash, Prashanth

2013-07-01

This study was designed to compare inorganic salivary calcium, phosphate, flow rate and pH of un-stimulated saliva and oral hygiene of healthy subjects, patients with periodontitis and dental caries and to correlate salivary calcium level with the number of intact teeth. The present study consisted of 90 patients aged between 18 and 55 years and were divided into three groups, periodontitis, dental caries and controls. Oral hygiene index-simplified, probing pocket depth, clinical attachment level and number of teeth present, teeth with active carious lesions were recorded. Salivary flow rate and pH was recorded and subjected to biochemical investigation. Estimation of inorganic calcium and phosphate was performed by colorimetric method. Results showed statistically significant increase in salivary inorganic calcium and phosphate levels, poor oral hygiene status, pH and salivary flow rate in patients with periodontitis when compared with dental caries group and controls. Individuals who have increased salivary inorganic calcium, phosphate, pH, flow rate and maintain poor oral hygiene could be at a higher risk for developing periodontitis and may have less dental caries and more number of intact teeth.

Hypoglycemic and Hypolipidemic Effects of the Cracked-Cap Medicinal Mushroom Phellinus rimosus (Higher Basidiomycetes) in Streptozotocin-Induced Diabetic Rats.

PubMed

Rony, Kuttikkadan A; Ajith, Thekkuttuparambil A; Janardhanan, Kainoor K

2015-01-01

Phellinus rimosus is a parasitic host specific polypore mushroom with profound antioxidant, antihepatotoxic, anti-inflammatory, antitumor, and antimutagenic activities. This study investigated the hypoglycemic and hypolipidemic activities of the wood-inhabiting polypore mushroom Ph. Rimosus in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced by single intraperitoneal injection of STZ (45 mg/kg) to Wistar rats. The effects of 30 days treatment with Ph. Rimosus (50 and 250 mg/ kg) and glibenclamide (0.65 mg/kg) on blood glucose level, serum insulin, serum lipid profile, liver glycogen, liver function enzymes, and non-enzymic and enzymic antioxidants activities in pancreas, liver, and kidney were evaluated in STZ-induced diabetic rats. Oral administration of Ph. Rimosus extract exhibited a significant reduction in blood glucose, triacylglycerol, total cholesterol, LDL-cholesterol, and liver function enzymes, and increased serum insulin, liver glycogen, and HDL-cholesterol levels in STZ-induced diabetic rats. Furthermore, Ph. Rimosus treatment increased antioxidant status in pancreas, liver, and kidney tissues with concomitant decreases in levels of thiobarbituric acid- reactive substances. Results of this study indicated that Ph. Rimosus possessed significant hypoglycemic and hypolipidemic activities and this effect may be related to its insulinogenic and antioxidant effect.

Association of salivary calcium, phosphate, pH and flow rate on oral health: A study on 90 subjects

PubMed Central

Fiyaz, Mohamed; Ramesh, Amitha; Ramalingam, Karthikeyan; Thomas, Biju; Shetty, Sucheta; Prakash, Prashanth

2013-01-01

Background and Objectives: This study was designed to compare inorganic salivary calcium, phosphate, flow rate and pH of un-stimulated saliva and oral hygiene of healthy subjects, patients with periodontitis and dental caries and to correlate salivary calcium level with the number of intact teeth. Materials and Methods: The present study consisted of 90 patients aged between 18 and 55 years and were divided into three groups, periodontitis, dental caries and controls. Oral hygiene index-simplified, probing pocket depth, clinical attachment level and number of teeth present, teeth with active carious lesions were recorded. Salivary flow rate and pH was recorded and subjected to biochemical investigation. Estimation of inorganic calcium and phosphate was performed by colorimetric method. Results: Results showed statistically significant increase in salivary inorganic calcium and phosphate levels, poor oral hygiene status, pH and salivary flow rate in patients with periodontitis when compared with dental caries group and controls. Interpretation and Conclusion: Individuals who have increased salivary inorganic calcium, phosphate, pH, flow rate and maintain poor oral hygiene could be at a higher risk for developing periodontitis and may have less dental caries and more number of intact teeth. PMID:24174724

Assessment of amiodarone-induced phospholipidosis in chimeric mice with a humanized liver.

PubMed

Sanoh, Seigo; Yamachika, Yuto; Tamura, Yuka; Kotake, Yaichiro; Yoshizane, Yasumi; Ishida, Yuji; Tateno, Chise; Ohta, Shigeru

2017-01-01

It is important to consider susceptibility to drug-induced toxicity between animals and humans. Chimeric mice with a humanized liver are expected to predict hepatotoxicity in humans. Drug-induced phospholipidosis (DIPL), in which phospholipids accumulate, is a known entity. In this study, we examined whether chimeric mice can reveal species differences in DIPL. Changes in various phosphatidylcholine (PhC) molecules were investigated in the liver of chimeric mice after administering amiodarone, which induces phospholipidosis. Liquid chromatography-tandem mass spectrometry revealed that levels of PhCs tended to increase in the liver after administration of amiodarone. The liver of chimeric mice consists of human hepatocytes and residual mouse hepatocytes. We used imaging mass spectrometry (IMS) to evaluate the increase of PhCs in human and mouse hepatocytes after administration of amiodarone. IMS visualizes localization of endogenous and exogenous molecules in tissues. The IMS analysis suggested that the localized levels of several PhCs tended to be higher in the human hepatocytes than those in mouse hepatocytes, and PhC levels changed in response to amiodarone. Chimeric mice with a humanized liver will be useful to evaluate species differences in DIPL between mice and humans.

Kinetic hindrance of Fe(II) oxidation at alkaline pH and in the presence of nitrate and oxygen in a facultative wastewater stabilization pond.

PubMed

Rockne, Karl J

2007-02-15

To better understand the dynamics of Fe2 + oxidation in facultative wastewater stabilization ponds, water samples from a three-pond system were taken throughout the period of transition from anoxic conditions with high aqueous Fe2 + levels in the early spring to fully aerobic conditions in late spring. Fe2 + levels showed a highly significant correlation with pH but were not correlated with dissolved oxygen (DO). Water column Fe2 + levels were modeled using the kinetic rate law for Fe2 + oxidation of Sung and Morgan.[5] The fitted kinetic coefficients were 5 +/- 3 x 10(6) M(- 2) atm(-1) min(-1); more than six orders of magnitude lower than typically reported. Comparison of four potential Fe redox couples demonstrated that the rhoepsilon was at least 3-4 orders of magnitude higher than would be expected based on internal equilibrium. Surprisingly, measured nitrate and DO (when present) were typically consistent with both nitrate (from denitrification) and DO levels (from aerobic respiration) predicted from equilibrium. Although the hydrous Fe oxide/FeCO3 couple was closest to equilibrium and most consistent with the observed pH dependence (in contrast to predicted lepidocrocite), Fe2 + oxidation is kinetically hindered, resulting in up to 10(7)-fold higher levels than expected based on both kinetic and equilibrium analyses.

Analysis of radiopacity, pH and cytotoxicity of a new bioceramic material.

PubMed

Souza, Letícia Chaves de; Yadlapati, Mamatha; Dorn, Samuel O; Silva, Renato; Letra, Ariadne

2015-01-01

RetroMTA® is a new hydraulic bioceramic indicated for pulp capping, perforations or root resorption repair, apexification and apical surgery. The aim of this study was to compare the radiopacity, pH variation and cytotoxicity of this material to ProRoot® MTA. Mixed cements were exposed to a digital x-ray along with an aluminum stepwedge for the radiopacity assay. pH values were verified after incubation period of 3, 24, 48, 72 and 168 hours. The cytotoxicity of each cement was tested on human periodontal ligament fibroblasts using a multiparametric assay. Data analysis was performed using ANOVA and Tukey'spost hoc in GraphPad Prism. ProRoot® MTA had higher radiopacity than RetroMTA®(p<0.001). No significant differences were observed for the pH of the materials throughout experimental periods (p>0.05) although pH levels of both materials reduced over time. Both ProRoot® MTA and RetroMTA® allowed for significantly higher cell viability when compared with the positive control (p<0.001). No statistical difference was observed between ProRoot® MTA and RetroMTA® cytotoxicity level in all test parameters, except for the ProRoot® MTA 48-hour extract media in the NR assay (p<0.05). The current study provides new data about the physicochemical and biological properties of Retro® MTA concerning radiopacity, pH and cytotoxic effects on human periodontal ligaments cells. Based on our findings, RetroMTA® meets the radiopacity requirements standardized by ANSI/ADA number 572, and similar pH values and biocompatibility to ProRoot® MTA. Further studies should be performed to evaluate additional properties of this new material.

Effect of Mobile Phone Usage on Nickel Ions Release and pH of Saliva in Patients Undergoing Fixed Orthodontic Treatment.

PubMed

Nanjannawar, Lalita Girish; Girme, Tejashree Suresh; Agrawal, Jiwanasha Manish; Agrawal, Manish Suresh; Fulari, Sangamesh Gurunath; Shetti, Shraddha Subhash; Kagi, Vishwal Ajith

2017-09-01

Hand held mobile phones are presently the most popular means of communication worldwide and have transformed our lives in many aspects. The widespread use of such devices have resulted in growing concerns regarding harmful effects of radiations emitted by them. This study was designed to evaluate the effects of mobile phone usage on nickel ion release as well as pH of saliva in patients with fixed orthodontic appliances. To assess the level of nickel ions in saliva and pH of saliva in mobile phone users undergoing fixed orthodontic treatment using inductively coupled plasma atomic emission spectrometry. A total of 42 healthy patients with fixed orthodontic appliance in mouth for a duration of six to nine months were selected for the study. They were divided into experimental group (n=21) consisting of mobile phone users and control group (n=21) of non mobile phone users. Saliva samples were collected from both the groups and nickel ion levels were measured using inductively coupled plasma-mass spectroscopy. The pH values were also assessed for both groups using pH meter. Unpaired t-test was used for the data analysis. Statistical analysis revealed that though the pH levels were reduced and the nickel ion levels were higher in the experimental group compared to the control group, the results were non significant. Mobile phone usage may affect the pH of saliva and result in increased release of nickel ions in saliva of patients with fixed orthodontic appliances in the oral cavity.

Structure of a microbial community in soil after prolonged addition of low levels of simulated acid rain

PubMed

Pennanen; Fritze; Vanhala; Kiikkila; Neuvonen; Baath

1998-06-01

Humus samples were collected 12 growing seasons after the start of a simulated acid rain experiment situated in the subarctic environment. The acid rain was simulated with H2SO4, a combination of H2SO4 and HNO3, and HNO3 at two levels of moderate acidic loads close to the natural anthropogenic pollution levels of southern Scandinavia. The higher levels of acid applications resulted in acidification, as defined by humus chemistry. The concentrations of base cations decreased, while the concentrations of exchangeable H+, Al, and Fe increased. Humus pH decreased from 3.83 to 3.65. Basal respiration decreased with decreasing humus pH, and total microbial biomass, measured by substrate-induced respiration and total amount of phospholipid fatty acids (PLFA), decreased slightly. An altered PLFA pattern indicated a change in the microbial community structure at the higher levels of acid applications. In general, branched fatty acids, typical of gram-positive bacteria, increased in the acid plots. PLFA analysis performed on the bacterial community growing on agar plates also showed that the relative amount of PLFA specific for gram-positive bacteria increased due to the acidification. The changed bacterial community was adapted to the more acidic environment in the acid-treated plots, even though bacterial growth rates, estimated by thymidine and leucine incorporation, decreased with pH. Fungal activity (measured as acetate incorporation into ergosterol) was not affected. This result indicates that bacteria were more affected than fungi by the acidification. The capacity of the bacterial community to utilize 95 different carbon sources was variable and only showed weak correlations to pH. Differences in the toxicities of H2SO4 and HNO3 for the microbial community were not found.

Sorption, Photodegradation, and Chemical Transformation of Naproxen and Ibuprofen in Soils and Water

NASA Astrophysics Data System (ADS)

Vulava, V. M.; Cory, W. C.; Murphey, V.; Ulmer, C.

2015-12-01

Trace levels of pharmaceutically active compounds (PhACs) are increasingly being found in municipal drinking water and natural streams around the world. PhACs enter natural water systems after passing through wastewater treatment plants that have proven to be relatively inefficient at removing them. Once they are released into the environment, they can undergo (1) soil sorption, (2) photodegradation, and/or (3) chemical transformation into structurally similar compounds. The overarching goal of this study is to understand the geochemical fate of common PhACs in the environment. Here we report on our studies with naproxen (NAP) and ibuprofen (IBP) in soils and water. Both compounds are complex nonpolar (aromatic) organic molecules with polar (carboxylic acid) functional groups. The carboxylic functional groups are likely to be deprotonated at environmentally relevant pHs (~4-8). Sorption studies of both compounds were conducted in clean and relatively acidic (soil pH ~4.5-6.5) natural soils that contained varying levels of organic matter (OM), clay minerals, and Fe oxides. OM was observed to play an important role in each of the above three processes. Sorption was observed to be stronger and nonlinear in higher OM soils, while weaker but still significant in lower OM, higher clay soils; the amphiphilic nature of NAP and IBP combined with the complex charged and nonpolar surfaces available in the soil was observed to control the sorption behavior. Both NAP and IBP underwent rapid photodegradation in aqueous suspensions when exposed to simulated sunlight. The degradation rates were observed to change in the presence of humic acid or fulvic acid. During sorption and photodegradation experiments, common transformation products were observed for both NAP and IBP. The transformation products produced were indicative of chemical transformation and not biological factors. Concentrations of the transformation products were significantly higher in the photoexposed aqueous suspensions compared to that formed in soil solutions. This study also helped in understanding the important role OM plays in geochemical fate of PhACs. The transformation products identified here are known to have higher ecotoxicity than the parent PhACs.

Evaluation of soil pH and moisture content on in-situ ozonation of pyrene in soils.

PubMed

Luster-Teasley, S; Ubaka-Blackmoore, N; Masten, S J

2009-08-15

In this study, pyrene spiked soil (300 ppm) was ozonated at pH levels of 2, 6, and 8 and three moisture contents. It was found that soil pH and moisture content impacted the effectiveness of PAH oxidation in unsaturated soils. In air-dried soils, as pH increased, removal increased, such that pyrene removal efficiencies at pH 6 and pH 8 reached 95-97% at a dose of 2.22 mg O(3)/mg pyrene. Ozonation at 16.2+/-0.45 mg O(3)/ppm pyrene in soil resulted in 81-98% removal of pyrene at all pH levels tested. Saturated soils were tested at dry, 5% or 10% moisture conditions. The removal of pyrene was slower in moisturized soils, with the efficiency decreasing as the moisture content increased. Increasing the pH of the soil having a moisture content of 5% resulted in improved pyrene removals. On the contrary, in the soil having a moisture content of 10%, as the pH increased, pyrene removal decreased. Contaminated PAH soils were stored for 6 months to compare the efficiency of PAH removal in freshly contaminated soil and aged soils. PAH adsorption to soil was found to increase with longer exposure times; thus requiring much higher doses of ozone to effectively oxidize pyrene.

Coral records of reef-water pH across the central Great Barrier Reef, Australia: assessing the influence of river runoff on inshore reefs

NASA Astrophysics Data System (ADS)

D'Olivo, J. P.; McCulloch, M. T.; Eggins, S. M.; Trotter, J.

2014-07-01

The boron isotopic (δ11Bcarb) compositions of long-lived Porites coral are used to reconstruct reef-water pH across the central Great Barrier Reef (GBR) and assess the impact of river runoff on inshore reefs. For the period from 1940 to 2009, corals from both inner as well as mid-shelf sites exhibit the same overall decrease in δ11Bcarb of 0.086 ± 0.033‰ per decade, equivalent to a~decline in seawater pH (pHsw) of ~ 0.017 ± 0.007 pH units per decade. This decline is consistent with the long-term effects of ocean acidification based on estimates of CO2 uptake by surface waters due to rising atmospheric levels. We also find that compared to the mid-shelf corals, the δ11Bcarb compositions for inner shelf corals subject to river discharge events, have higher and more variable values and hence higher inferred pHsw values. These higher δ11Bcarb values for inner-shelf corals are particularly evident during wet years, despite river waters having lower pH. The main effect of river discharge on reef-water carbonate chemistry thus appears to be from higher nutrients driving increased phytoplankton productivity, resulting in the drawdown of pCO2 and increase in pHsw. Increased primary production therefore has the potential to counter the more transient effects of low pH river water (pHrw) discharged into near-shore environments. Importantly however, inshore reefs also show a consistent pattern of sharply declining coral growth that coincides with periods of high river discharge. This occurs despite these reefs having higher pHsw values and hence higher seawater aragonite saturation states, demonstrating the over-riding importance of local reef-water quality on coral reef health.

Reduced carbon sequestration potential of biochar in acidic soil.

PubMed

Sheng, Yaqi; Zhan, Yu; Zhu, Lizhong

2016-12-01

Biochar application in soil has been proposed as a promising method for carbon sequestration. While factors affecting its carbon sequestration potential have been widely investigated, the number of studies on the effect of soil pH is limited. To investigate the carbon sequestration potential of biochar across a series of soil pH levels, the total carbon emission, CO 2 release from inorganic carbon, and phospholipid fatty acids (PLFAs) of six soils with various pH levels were compared after the addition of straw biochar produced at different pyrolysis temperatures. The results show that the acidic soils released more CO 2 (1.5-3.5 times higher than the control) after the application of biochar compared with neutral and alkaline soils. The degradation of both native soil organic carbon (SOC) and biochar were accelerated. More inorganic CO 2 release in acidic soil contributed to the increased degradation of biochar. Higher proportion of gram-positive bacteria in acidic soil (25%-36%) was responsible for the enhanced biochar degradation and simultaneously co-metabolism of SOC. In addition, lower substrate limitation for bacteria, indicated by higher C-O stretching after the biochar application in the acidic soil, also caused more CO 2 release. In addition to the soil pH, other factors such as clay contents and experimental duration also affected the phsico-chemical and biotic processes of SOC dynamics. Gram-negative/gram-positive bacteria ratio was found to be negatively related to priming effects, and suggested to serve as an indicator for priming effect. In general, the carbon sequestration potential of rice-straw biochar in soil reduced along with the decrease of soil pH especially in a short-term. Given wide spread of acidic soils in China, carbon sequestration potential of biochar may be overestimated without taking into account the impact of soil pH. Copyright © 2016 Elsevier B.V. All rights reserved.

[Alterations in tears aqueous layer during cytostatics treatment].

PubMed

Wojciechowska, Katarzyna; Wieckowska-Szakiel, Marzena; Rózalska, Barbara; Jurowski, Piotr

2013-01-01

The aim of the study was to evaluate tears secretion, pH and lysozyme activity in tears aqueous layer during chemotherapy in lung, breast and bowel cancer. 36 patients were enrolled to the study. Depending on the type of cancer and type of chemotherapy patients were divided into three groups. Group I (12 patients) diagnosed with non-small-cell lung cancer treated with PE schema (cisplatin, etoposide), Group II (12 patients) with breast cancer treated with FAC schema (fluorouracil, doxorubicin, cyclophosphamide), Group III (12 patients) with bowel cancer treated with FU/LV schema (fluorouracil, leucovorin). In all the patients: Schirmer's I test, pH measurements and lysozyme test were performed. Patients were examined before chemotherapy, after 2nd, 4th, 6th cycle. In group I and II lowering of tears secretion (p < 0.001) was revealed. In group III there was higher tears secretion (p < 0.001). PH was lowered after 2nd chemotherapy course in group I and II. In further treatment pH value were in the same lower level as after the second course. In group III there was higher pH--more alkaline (p < 0.001) after 2nd cycle of treatment and it was on the same level to the end of the examination process. Lowering of lysozyme activity in the tears film in all groups (p < 0.001) was established. The higher alterations of the lysozyme activity were observed in group treated with FAC schema. Cytostatic treatment has major influence on tears aqueous layer causing alterations of tears secretions. PH alterations depending on type of chemotherapy was observed. Lowering of lysozyme activity in tears was observed. All the deteriorations aggravate with duration of chemotherapy. Alterations of tears film parameters during chemotherapy may influence upon eye surface homeostasis and infectious complication. tears aqueous layer, Schirmer's test, lysozyme activity, tears pH.

The vulvar skin microenvironment: influence of different panty liners on temperature, pH and microflora.

PubMed

Runeman, Bo; Rybo, Göran; Forsgren-Brusk, Ulla; Larkö, Olle; Larsson, Peter; Faergemann, Jan

2004-01-01

The aim of this study was to confirm findings that vapour-impermeable panty liners might impair skin climate, and to assess their impact on the skin microflora. Temperature, surface pH and aerobic microflora were measured on vulvar skin of 102 women. The mean skin temperature was 1.1 degrees C higher when using a vapour-impermeable panty liner compared with not using one. Use of panty liners with vapour-permeable back sheets and acidic cores resulted in skin temperature, pH and microflora levels that were very close to those observed in persons not using liners. The temperature, pH and total number of microorganisms were significantly lower for users of vapour-permeable panty liners than for users of vapour-impermeable ones (p <0.05, p<0.001 and p<0.001, respectively). The microorganism densities were usually higher when using the vapour-impermeable panty liner, but mean differences were minor. The use of panty liners seems not to imply a microbial risk for normal, healthy women.

Seasonal variations and source identification of selected organic acids associated with PM10 in the coastal area of Southeastern China

NASA Astrophysics Data System (ADS)

Wu, Shui-Ping; Schwab, James; Liu, Bi-Lian; Li, Tsung-Chang; Yuan, Chung-Shin

2015-03-01

PM10 aerosols from the coastal area of Southeastern China were collected from April 2010 to March 2011 and were measured for C2-C10 dicarboxylic acids, phthalic acids (Ph) and five fatty acids (palmitic, stearic, oleic, linoleic and elaidic acids). For all sites and seasons, molecular distributions of diacids were always characterized by a predominance of oxalic acid (C2), with a relative abundance of 68-87%, followed by malonic acid (C3) and by either succinic acid (C4) or phthalic acid (Ph). This observed molecular composition was different from that in Chinese megacities where Ph was significantly higher than C3 and C4 diacids, which was likely due to the less intensive traffic emissions in the coastal area. Seasonal means of total diacids ranged between 394 and 547 ng m- 3 at the coastal urban sites and between 163 and 245 ng m- 3 at off-island sites. These levels were much lower than those reported in Chinese megacities (668-1568 ng m- 3) and slightly lower than those in Jeju Island, Korea (464-744 ng m- 3) but higher than those in marine and continental background locations. In all seasons, saturated fatty acids were significantly higher than unsaturated fatty acids due to their greater photochemical stabilities in the atmosphere. Most organic acids showed higher levels in spring and winter and lower levels in summer and fall, which was likely due to the influence of transport and meteorology. The diagnostic ratios of malonic acid to succinic acid (C3/C4), adipic acid to azelaic acid (C6/C9) and phthalic acid to azelaic acid (Ph/C9) were significantly higher in summer than in winter. These diagnostic ratios in the sampled ambient aerosols were completely different from those in primary emissions, suggesting the importance of photochemical production - especially in summer. The diurnal variations of diacids and fatty acid as well as the diagnostic ratios are associated with higher solar radiation and anthropogenic activities during the daytime. Principal component analysis results provide evidence that photochemical oxidation of unsaturated fatty acids and volatile organic compounds is the most important source of diacids. In this analysis, primary sources were found to be minor (traffic and food cooking) or non-existent (biomass burning and crustal dust). Components with high loadings of Ph and unsaturated fatty acids can be regarded as representative of primary traffic emissions.

Regulating NETosis: Increasing pH Promotes NADPH Oxidase-Dependent NETosis

PubMed Central

Khan, Meraj A.; Philip, Lijy M.; Cheung, Guillaume; Vadakepeedika, Shawn; Grasemann, Hartmut; Sweezey, Neil; Palaniyar, Nades

2018-01-01

Neutrophils migrating from the blood (pH 7.35–7.45) into the surrounding tissues encounter changes in extracellular pH (pHe) conditions. Upon activation of NADPH oxidase 2 (Nox), neutrophils generate large amounts of H+ ions reducing the intracellular pH (pHi). Nevertheless, how extracellular pH regulates neutrophil extracellular trap (NET) formation (NETosis) is not clearly established. We hypothesized that increasing pH increases Nox-mediated production of reactive oxygen species (ROS) and neutrophil protease activity, stimulating NETosis. Here, we found that raising pHe (ranging from 6.6 to 7.8; every 0.2 units) increased pHi of both activated and resting neutrophils within 10–20 min (Seminaphtharhodafluor dual fluorescence measurements). Since Nox activity generates H+ ions, pHi is lower in neutrophils that are activated compared to resting. We also found that higher pH stimulated Nox-dependent ROS production (R123 generation; flow cytometry, plate reader assay, and imaging) during spontaneous and phorbol myristate acetate-induced NETosis (Sytox Green assays, immunoconfocal microscopy, and quantifying NETs). In neutrophils that are activated and not resting, higher pH stimulated histone H4 cleavage (Western blots) and NETosis. Raising pH increased Escherichia coli lipopolysaccharide-, Pseudomonas aeruginosa (Gram-negative)-, and Staphylococcus aureus (Gram-positive)-induced NETosis. Thus, higher pHe promoted Nox-dependent ROS production, protease activity, and NETosis; lower pH has the opposite effect. These studies provided mechanistic steps of pHe-mediated regulation of Nox-dependent NETosis. Raising pH either by sodium bicarbonate or Tris base (clinically known as Tris hydroxymethyl aminomethane, tromethamine, or THAM) increases NETosis. Each Tris molecule can bind 3H+ ions, whereas each bicarbonate HCO3− ion binds 1H+ ion. Therefore, the amount of Tris solution required to cause the same increase in pH level is less than that of equimolar bicarbonate solution. For that reason, regulating NETosis by pH with specific buffers such as THAM could be more effective than bicarbonate in managing NET-related diseases. PMID:29487850

Low pH-Induced Changes of Antioxidant Enzyme and ATPase Activities in the Roots of Rice (Oryza sativa L.) Seedlings

PubMed Central

Zhang, Yi-Kai; Zhu, De-Feng; Zhang, Yu-Ping; Chen, Hui-Zhe; Xiang, Jing; Lin, Xian-Qing

2015-01-01

Soil acidification is the main problem in the current rice production. Here, the effects of low pH on the root growth, reactive oxygen species metabolism, plasma membrane functions, and the transcript levels of the related genes were investigated in rice seedlings (Oryza sativa L.) in a hydroponic system at pH 3.5, 4.5, and 5.5. There were two hybrid rice cultivars in this trial, including Yongyou 12 (YY12, a japonica hybrid) and Zhongzheyou 1 (ZZY1, an indica hybrid). Higher H+ activity markedly decreased root length, the proportion of fine roots, and dry matter production, but induced a significant accumulation of hydrogen peroxide (H2O2), and led to serious lipid peroxidation in the roots of the two varieties. The transcript levels of copper/zinc superoxide dismutase 1 (Cu/Zn SOD1), copper/zinc superoxide dismutase 2 (Cu/Zn SOD2), catalase A (CATA) and catalase B (CATB) genes in YY12 and ZZY1 roots were significantly down-regulated after low pH exposure for two weeks. Meanwhile, a significant decrease was observed in the expression of the P-type Ca2+-ATPases in roots at pH 3.5. The activities of antioxidant enzymes (SOD, CAT) and plasma membrane (PM) Ca2+-ATPase in the two varieties were dramatically inhibited by strong rhizosphere acidification. However, the expression levels of ascorbate peroxidase 1 (APX1) and PM H+-ATPase isoform 7 were up-regulated under H+ stress compared with the control. Significantly higher activities of APX and PM H+-ATPase could contribute to the adaptation of rice roots to low pH. PMID:25719552

Association of cardiac troponin I with disease severity and outcomes in patients with pulmonary hypertension.

PubMed

Vélez-Martínez, Mariella; Ayers, Colby; Mishkin, Joseph D; Bartolome, Sonja B; García, Christine K; Torres, Fernando; Drazner, Mark H; de Lemos, James A; Turer, Aslan T; Chin, Kelly M

2013-06-15

Previous studies have identified cardiac troponin I (cTnI) as an important marker in pulmonary hypertension (PH) prognosis. However, traditional assays are limited by poor sensitivity, even among patients at high risk. cTnI was measured in 255 PH patients using a new highly sensitive (hs) assay. Other measures included demographics, creatinine, 6-minute walk distance, hemodynamics, cardiac magnetic resonance imaging, and B-type natriuretic peptide level. The association between cTnI and survival was assessed using Kaplan-Meier analysis and Cox regression. cTnI was detectable with the hs assay in 95% of the patients with a median level of 6.9 pg/ml (IQR 2.7-12.6 pg/ml). Higher cTnI levels associated with higher levels of B-type natriuretic peptide, shorter 6-minute walk distance, and more severe hemodynamic and cardiac magnetic resonance imaging abnormalities. During a median follow-up of 3.5 years, 60 individuals died. Unadjusted event rates increased across higher cTnI quartiles (3, 5, 13, 17 events/100 person-years, respectively, p trend = 0.002). cTnI in the fourth (vs first) quartile remained associated with death in a final stepwise multivariable model that included clinical variables and hemodynamics (adjusted hazard ratio 5.3, 95% confidence interval 1.8-15.6). In conclusion, cTnI levels, detectable with a novel hs assay, identify patients with PH who have more severe hemodynamic and cardiac structural abnormalities and provide novel and independent prognostic information. This hs assay has the potential to detect more at-risk patients and improve current risk-stratification algorithms. Copyright © 2013 Elsevier Inc. All rights reserved.

Salivary Distinctiveness and Modifications in Males with Diabetes and Behçet's Disease

PubMed Central

Alhaffar, Iyad

2017-01-01

Oral diseases associated with systematic diseases as metabolic and vasculitic have been included in this paper. This will enhance our understanding of the salivary function in promoting healthy oral condition. The study investigates the effects of type I and type II diabetes mellitus in well-controlled diabetic patients, in addition to Behçet disease (BD) on saliva flow rate (SFR), pH, the decay, missing, and filled tooth (DMFT) index, glucose, and major earth-alkaline ions (Ca2+ and Mg2+) compared to healthy males and age-matched controls. Saliva samples were collected from 1403 male human subjects, distributed on 7 levels including 3 control groups, and analyzed. The symptoms and clinical observations were enrolled. A preprandial salivary glucose has illustrated statistically strong significant and positive correlations with HbA1c and blood glucose levels. TIDM saliva showed lower pH, SFR, and Ca2+ but higher Mg2+, caries risk, and poor metabolic control. These led to dysfunction of secretory capacity of salivary glands. TIIDM proved higher SFR, DMFT, and glucose than TIDM patients. DM oral calcium has decreased by age while magnesium sharply slopes at seniority. BD oral fluid is associated with lower glucose and minerals but noticeably with both higher pH and DMFT. PMID:28321337

Salivary Distinctiveness and Modifications in Males with Diabetes and Behçet's Disease.

PubMed

Aljerf, Loai; Alhaffar, Iyad

2017-01-01

Oral diseases associated with systematic diseases as metabolic and vasculitic have been included in this paper. This will enhance our understanding of the salivary function in promoting healthy oral condition. The study investigates the effects of type I and type II diabetes mellitus in well-controlled diabetic patients, in addition to Behçet disease (BD) on saliva flow rate (SFR), pH, the decay, missing, and filled tooth (DMFT) index, glucose, and major earth-alkaline ions (Ca 2+ and Mg 2+ ) compared to healthy males and age-matched controls. Saliva samples were collected from 1403 male human subjects, distributed on 7 levels including 3 control groups, and analyzed. The symptoms and clinical observations were enrolled. A preprandial salivary glucose has illustrated statistically strong significant and positive correlations with HbA 1c and blood glucose levels. TIDM saliva showed lower pH, SFR, and Ca 2+ but higher Mg 2+ , caries risk, and poor metabolic control. These led to dysfunction of secretory capacity of salivary glands. TIIDM proved higher SFR, DMFT, and glucose than TIDM patients. DM oral calcium has decreased by age while magnesium sharply slopes at seniority. BD oral fluid is associated with lower glucose and minerals but noticeably with both higher pH and DMFT.

Associations among Gastric Juice pH, Atrophic Gastritis, Intestinal Metaplasia and Helicobacter pylori Infection.

PubMed

Sung, Jihee; Kim, Nayoung; Lee, Jongchan; Hwang, Young-Jae; Kim, Hyoung Woo; Chung, Jung Wha; Kim, Jin-Wook; Lee, Dong Ho

2018-03-15

Gastric juice plays a crucial role in the physiology of the stomach. The aim of this study is to evaluate associations among the pH of gastric juice, atrophic gastritis (AG), intestinal metaplasia (IM), pepsinogen, and Helicobacter pylori infection. Gastric biopsies and juice were collected from 46 subjects who underwent endoscopies at Seoul National University Bundang Hospital between November 2011 and March 2013. H. pylori , AG and IM were evaluated, and pepsinogen I or II, I/II ratio, and interleukin (IL)-1β levels were measured. The mean pH of gastric juice was higher in the H. pylori -positive group (n=17) than that in the H. pylori -negative group (n=29) (4.54 vs 2.46, p=0.002). When patients were divided into pH ＜3 (n=28) and pH ≥3 (n=18) groups, H. pylori was lower in the pH ＜3 group (21.4%) than in the pH ≥3 group (61.1%) (p=0.007). The pH ≥3 group demonstrated AG and IM more frequently than the pH ＜3 group in the body (p=0.047 and p=0.051, respectively) but not in the antrum. There were no differences in pepsinogen I or II, I/II ratio, and IL-1β levels between the two groups. There is a relationship between chronic H. pylori infection and gastric juice pH ≥3, which may originate from AG and IM in the body.

Effects of potassium chloride and potassium bicarbonate in the diet on urinary pH and mineral excretion of adult cats.

PubMed

Passlack, Nadine; Brenten, Thomas; Neumann, Konrad; Zentek, Jürgen

2014-03-14

Low dietary K levels have been associated with increasing renal Ca excretion in humans, indicating a higher risk of calcium oxalate (CaOx) urolith formation. Therefore, the present study aimed to investigate whether dietary K also affects the urine composition of cats. A total of eight adult cats were fed diets containing 0·31 % native K and 0·50, 0·75 and 1·00 % K from KCl or KHCO₃ and were evaluated for the effects of dietary K. High dietary K levels were found to elevate urinary K concentrations (P<0·001). Renal Ca excretion was higher in cats fed the KCl diets than in those fed the KHCO₃ diets (P=0·026), while urinary oxalate concentrations were generally lower in cats fed the KCl diets and only dependent on dietary K levels in cats fed the KHCO₃ diets (P<0·05). Fasting urine pH increased with higher dietary K levels (P=0·022), reaching values of 6·38 (1·00 % KCl) and 7·65 (1·00 % KHCO₃). K retention was markedly negative after feeding the cats with the basal diet (-197 mg/d) and the 0·50 % KCl diet (-131 mg/d), while the cats tended to maintain their balance on being fed the highest-KCl diet (-23·3 mg/d). In contrast, K from KHCO₃ was more efficiently retained (P=0·018), with K retention being between -82·5 and 52·5 mg/d. In conclusion, the dietary inclusion of KHCO₃ instead of KCl as K source could be beneficial for the prevention of CaOx urolith formation in cats, since there is an association between a lower renal Ca excretion and a generally higher urine pH. The utilisation of K is distinctly influenced by the K salt, which may be especially practically relevant when using diets with low K levels.

Chemical and sensory characteristics of frozen wheygurt with the addition of taro and lesser yam flours as thickening agent

NASA Astrophysics Data System (ADS)

Nurhartadi, E.; Utami, R.; Widowati, E.; Karunawati, B. M.

2018-01-01

Cheese whey is a waste product from cheese processing. It has low solid contents thus required the addition of a thickening agent. Lactic acid bacteria could utilize it in the fermented drink. This research aims to study the effect of taro and lesser yam flour addition as a thickening agent on chemical and sensory characteristics of frozen wheygurt. This research used Complete Randomized Design (CRD) with one factor that is variation ratio of taro and lesser yam flour F1 (4: 0), F2 (3: 1), F3 (2: 2), F4 (1: 3), F5 (0: 4). The number of lactic acid bacteria cell determined by using hemocytometer. The lactic acid content determined by the titrimetric method by using 0.1 N NaOH and phenolphthalein as indicator. pH value measured with pH meter. Sensory characteristics evaluated using hedonic test. The result showed that the addition of taro and lesser yam flour have a significant effect on the number of lactic acid bacteria in frozen wheygurt. The higher lesser yam flour addition, the higher lactic acid bacteria count on frozen wheygurt, due to lesser yam higher glucose and fructo-oligosaccharide content than taro. The higher lesser yam addition, the higher the lactic acid produced. The higher the total bacteria and higher levels of lactic acid, the lower the pH obtained. The conclusion of this study is addition ratio of taro and lesser yam flour effect on the chemical characteristics of frozen wheygurt. There is no difference in the level of acceptance of the panelists in sensory evaluation.

Effect of environmental stress on the ability of Listeria monocytogenes Scott A to attach to food contact surfaces.

PubMed

Smoot, L M; Pierson, M D

1998-10-01

Attachment of Listeria monocytogenes Scott A to Buna-N rubber and stainless steel under different temperature and pH conditions at the time of cell growth or at the time of attachment was investigated. All experiments were conducted using sterile phosphate buffer to avoid cell growth during exposure to the test surfaces. Numbers of attached cells increased with increasing attachment temperature (10 to 45 degrees C) and exposure time for both test surfaces. Maximum levels of attached cells were obtained when cell growth occurred at 30 degrees C. Downward, but not upward, shifts in the cell suspension holding temperature prior to attachment to Buna-N rubber resulted in reduced adhered cell populations. Maximum levels of adhered cells to Buna-N rubber were not affected by adjustments of the attachment medium pH between 4 and 9. However, after short contact times (i.e., less than 30 min), levels of attached cells were lower when attachment occurred under alkaline conditions. Growth pH was also found to affect the levels of adhered cell populations to Buna-N rubber. L. monocytogenes Scott A attached to stainless steel at higher levels for all temperature and pH parameters evaluated in this study.

[Effects of thiourea on pH and availability of metal ions in acid red soil].

PubMed

Yang, Bo; Wang, Wen; Zeng, Qing-Ru; Zhou, Xi-Hong

2014-03-01

Through the simulation research, the effects of application of thiourea and urea on pH and availability of metal ions in acid red soil were studied, and the results showed that after applying urea, the soil pH increased in the first experimental stage and then reduced gradually to a low level, however, decreased trends of soil pH values were inhibited by the application of thiourea, especially when the concentration of thiourea reached to 5.0 mmol x kg(-1) dry soil, the soil pH was stable at high level, which exceeded to 6.0. It proved that the application of thiourea could inhibit the soil acidification due to urea application. After applying urea with different concentrations of thiourea, the available contents of Zn and Al decreased with the increasing concentration of thiourea, nevertheless, when the concentration of thiourea reached to 5.0 mmol x kg(-1), the available content of Mn was stable at high level which was over 110 mg x kg(-1). In addition, the results showed a highly significant negative correlation between the soil pH and the available content of Cu, Zn and Al, but for Mn, no discipline was found between the soil pH and the availability after applying thiourea. Moreover, the soil pH became higher after applying urea with thiourea compared to add urea only, which led to the decreasing of available content of Al, and it was benefited for the control of the phytotoxic effect of Al. The available content of Mn in the soil not only depended on soil pH but also the content of thiourea due to its redox and complexing reaction with Mn.

Effect of pH on Cleavage of Glycogen by Vaginal Enzymes

PubMed Central

Spear, Greg T.; McKenna, Mary; Landay, Alan L.; Makinde, Hadijat; Hamaker, Bruce; French, Audrey L.; Lee, Byung-Hoo

2015-01-01

Glycogen expressed by the lower genital tract epithelium is believed to support Lactobacillus growth in vivo, although most genital isolates of Lactobacillus are not able to use glycogen as an energy source in vitro. We recently reported that α-amylase is present in the genital fluid of women and that it breaks down glycogen into small carbohydrates that support growth of lactobacilli. Since the pH of the lower genital tract can be very low, we determined how low pH affects glycogen processing by α-amylase. α-amylase in saliva degraded glycogen similarly at pH 6 and 7, but activity was reduced by 52% at pH 4. The glycogen degrading activity in nine genital samples from seven women showed a similar profile with an average reduction of more than 50% at pH 4. However, two samples collected from one woman at different times had a strikingly different pH profile with increased glycogen degradation at pH 4, 5 and 6 compared to pH 7. This second pH profile did not correlate with levels of human α-acid glucosidase or human intestinal maltase glucoamylase. High-performance anion-exchange chromatography showed that mostly maltose was produced from glycogen by samples with the second pH profile in contrast to genital α-amylase that yielded maltose, maltotriose and maltotetraose. These studies show that at low pH, α-amylase activity is reduced to low but detectable levels, which we speculate helps maintain Lactobacillus growth at a limited but sustained rate. Additionally, some women have a genital enzyme distinct from α-amylase with higher activity at low pH. Further studies are needed to determine the identity and distribution of this second enzyme, and whether its presence influences the makeup of genital microbiota. PMID:26171967

SABRE hyperpolarisation of vitamin B3 as a function of pH.

PubMed

Olaru, A M; Burns, M J; Green, G G R; Duckett, S B

2017-03-01

In this work we describe how the signal enhancements obtained through the SABRE process in methanol- d 4 solution are significantly affected by pH. Nicotinic acid (vitamin B3, NA ) is used as the agent, and changing pH is shown to modify the level of polarisation transfer by over an order of magnitude, with significant improvements being seen in terms of the signal amplitude and relaxation rate at high pH values. These observations reveal that manipulating pH to improve SABRE enhancements levels may improve the potential of this method to quantify low concentrations of analytes in mixtures. 1 H NMR spectroscopy results link this change to the form of the SABRE catalyst, which changes with pH, resulting in dramatic changes in the magnitude of the ligand exchange rates. The presented data also uses the fact that the chemical shifts of the nicotinic acids NMR resonances are affected by pH to establish that hyperpolarised 1 H-based pH mapping with SABRE is possible. Moreover, the strong polarisation transfer field dependence shown in the amplitudes of the associated higher order longitudinal terms offers significant opportunities for the rapid detection of hyperpolarised NA in H 2 O itself without solvent suppression. 1 H and 13 C MRI images of hyperpolarised vitamin B3 in a series of test phantoms are presented that show pH dependent intensity and contrast. This study therefore establishes that when the pH sensitivity of NA is combined with the increase in signal gain provided for by SABRE hyperpolarisation, a versatile pH probe results.

Novel red cell indices indicating reduced availability of iron are associated with high erythropoietin concentration and low ph level in the venous cord blood of newborns.

PubMed

Ervasti, Mari; Sankilampi, Ulla; Heinonen, Seppo; Punnonen, Kari

2008-08-01

There is evidence that an elevated erythropoietin (EPO) concentration is associated with signs of iron deficient erythropoiesis. The aim of this study was to evaluate the iron status by means of novel cellular indices and serum iron markers and to determine whether these are associated with EPO and pH in the venous cord blood of 193 full-term newborns. There were positive correlations between EPO and the percentage of hypochromic red blood cells (%HYPOm) and reticulocytes (%HYPOr) [r = 0.45 (p < 0.001) and r = 0.56 (p < 0.001), respectively]. %HYPOm and %HYPOr also had negative correlations with pH [r = -0.53 (p = 0.001) and r = -0.46 (p = 0.001), respectively]. Newborns who had low pH (pH < or =7.15, n = 16) had significantly higher %HYPOm, %HYPOr, and serum transferrin receptor and transferrin concentrations in their cord blood than newborns with normal pH. Thus, in newborn cord blood, the higher number of red cells and reticulocytes with lower Hb content may have impaired the oxygen carrying capacity that has been a trigger for EPO production. Furthermore, signs of lower hemoglobinization of red cells are associated with low umbilical vein pH in the newborns, indicating an increased risk of birth asphyxia.

Effect of Mobile Phone Usage on Nickel Ions Release and pH of Saliva in Patients Undergoing Fixed Orthodontic Treatment

PubMed Central

Girme, Tejashree Suresh; Agrawal, Jiwanasha Manish; Agrawal, Manish Suresh; Fulari, Sangamesh Gurunath; Shetti, Shraddha Subhash; Kagi, Vishwal Ajith

2017-01-01

Introduction Hand held mobile phones are presently the most popular means of communication worldwide and have transformed our lives in many aspects. The widespread use of such devices have resulted in growing concerns regarding harmful effects of radiations emitted by them. This study was designed to evaluate the effects of mobile phone usage on nickel ion release as well as pH of saliva in patients with fixed orthodontic appliances. Aim To assess the level of nickel ions in saliva and pH of saliva in mobile phone users undergoing fixed orthodontic treatment using inductively coupled plasma atomic emission spectrometry. Materials and Methods A total of 42 healthy patients with fixed orthodontic appliance in mouth for a duration of six to nine months were selected for the study. They were divided into experimental group (n=21) consisting of mobile phone users and control group (n=21) of non mobile phone users. Saliva samples were collected from both the groups and nickel ion levels were measured using inductively coupled plasma-mass spectroscopy. The pH values were also assessed for both groups using pH meter. Unpaired t-test was used for the data analysis. Results Statistical analysis revealed that though the pH levels were reduced and the nickel ion levels were higher in the experimental group compared to the control group, the results were non significant. Conclusion Mobile phone usage may affect the pH of saliva and result in increased release of nickel ions in saliva of patients with fixed orthodontic appliances in the oral cavity. PMID:29207841

[Effects of soil acidity on Pinus resinosa seedlings photosynthesis and chlorophyll fluorescence].

PubMed

Liu, Shuang; Wang, Qing-cheng; Liu, Ya-li; Tian, Yu-ming; Sun, Jing; Xu, Jing

2009-12-01

Red pine (Pinus resinosa) is one of the most important tree species for timber plantation in North America, and preliminary success has been achieved in its introduction to the mountainous area of Northeast China since 2004. In order to expand its growth area in other parts of Northeast China, a pot experiment was conducted to study the adaptability of this tree species to varying soil acidity. P. resinosa seedlings were grown in soils with different acidity (pH = 4.5, 5.5, 6.5, 7.5, and 8.0) to test the responses of their photosynthesis and chlorophyll fluorescence parameters to soil pH levels, and the appropriate soil acidity was evaluated. Dramatic responses in chlorophyll a and b contents, Pn and chlorophyll fluorescence parameters (Fo, Fm, Fv, Fv/Fm, and phi(PS II)) were detected under different soil acidity (P < 0.05), with the highest chlorophyll content and Pn under soil pH 5.5, and significantly lower chlorophyll content and Pn under soil pH 7.5 and 8.0. The chlorophyll content and Pn were 41% and 50%, and 61% and 88% higher under soil pH 5.5 than under soil pH 7.5 and 8.0. The seedlings had a significant photosynthetic inhibition under soil pH 7.5 and 8.0, but the highest Fv/Fm and phi (PS II) under soil pH 5.5. Comparing with those under soil pH 7.5 and 8.0, the Fv/Fm and phi (PS II) under soil pH 5.5 were 8% and 12%, and 22% and 35% higher, respectively. It was suggested that soil pH 5.5 was most appropriate for P. resinosa growth.

Acute metformin overdose: examining serum pH, lactate level, and metformin concentrations in survivors versus nonsurvivors: a systematic review of the literature.

PubMed

Dell'Aglio, Damon M; Perino, Louis J; Kazzi, Ziad; Abramson, Jerome; Schwartz, Michael D; Morgan, Brent W

2009-12-01

Metformin is known to cause potentially fatal metabolic acidosis with an increased lactate level in both overdose and therapeutic use. No association between mortality and serum pH, lactate level, or metformin concentrations, though intuitive, has yet been described. This systematic literature review is designed to evaluate the association between mortality and serum pH, lactate level, and metformin concentrations in acute metformin overdose. We reviewed the literature by using the MEDLINE, EMBASE, CINAHL, and TOXNET databases for cases of metformin overdose with documented mortality data and values of serum pH, lactate level, and metformin concentrations. When available, patient age, patient sex, and whether patients received intravenous sodium bicarbonate therapy or hemodialysis were also analyzed. Cases meeting inclusion criteria were analyzed to determine whether a difference in distribution of nadir serum pH, peak serum lactate level, or peak serum metformin concentrations existed between overdose survivors and nonsurvivors. We identified 10 articles that had 1 or more cases meeting our inclusion criteria. In total, there were 22 cases of metformin overdose (5/22 died) that met inclusion criteria. No intentional overdose patients died whose serum pH nadir was greater than 6.9, maximum lactate concentration less than 25 mol/L, or maximum metformin concentration less than 50 microg/mL (therapeutic range 1 to 2 microg/mL). Intentional overdose patients with a nadir serum pH less than 6.9 had 83% mortality (5/6), those with lactate concentration greater than 25 mmol/L had 83% mortality (5/6), and those with metformin concentration greater than 50 microg/mL had 38% mortality (5/12). Nadir serum pH and peak serum lactate and metformin concentration distributions in survivors and nonsurvivors revealed that survivors had a median nadir pH of 7.30, interquartile range (IQR) 7.22, 7.36; nonsurvivors, a median nadir pH of 6.71, IQR 6.71, 6.73; survivors, a median peak lactate level of 10.8 mmol/L, IQR 4.2, 12.9; nonsurvivors, a median peak lactate level of 35.0 mmol/L, IQR 33.3, 39.0; survivors, a median peak metformin level of 42 microg/mL, IQR 6.6, 67.6; and nonsurvivors, a median peak metformin level of 110 microg/mL, IQR 110, 110. No cases of acute metformin overdose meeting the study's inclusion criteria were found in which patients with a nadir serum pH greater than 6.9, peak serum lactate concentrations less than 25 mmol/L, or peak serum metformin concentrations less than 50 microg/mL died. Patients with acute metformin overdose who died had much lower serum pH nadirs and much higher peak serum lactate and metformin concentrations than those who survived.

Effects of Restoring the Primary Dentition with Stainless-Steel Crowns on Children's Salivary Nickel and Chromium Levels, and the Associations with Saliva pH: a Preliminary Before-After Clinical Trial.

PubMed

Basir, Leila; Meshki, Razieh; Behbudi, Azam; Rakhshan, Vahid

2018-05-23

Nickel and chromium existing in stainless-steel crowns (SSCs, used in pediatric dentistry) might be cytotoxic and allergenic. However, no in vivo studies have examined their salivary levels in children using SSCs, or in young children without SSCs. Also, the effect of acidity on metal ion release has not yet been evaluated in any previous in vivo studies in the whole literature. Therefore, this preliminary before-after clinical trial was conducted. Salivary nickel/chromium levels of 30 children before and after 2 months of placement of SSCs were measured using atomic absorption spectrophotometry. Salivary pH was measured with a digital pH meter. The effects of treatment, pH, number of SSCs, gender, and age on salivary ions were analyzed statistically (α = 0.05, β = 0.15). Salivary nickel concentrations increased from 4.9010 ± 4.7390 to 5.6320 ± 4.7210 μg/L (P = 0.000, paired t test). Chromium increased from 0.3273 ± 0.5214 to 0.4199 ± 0.6404 μg/L (P = 0.016). Saliva pH increased from 6.81 ± 0.52 to 7.04 ± 0.47 (P = 0.000). Ion levels were not correlated with pH (P > 0.14), except chromium in the follow-up (rho = - 0.435, P = 0.016). Nickel increase (but not chromium increase) was correlated with pH increase (rho = 0.367, P = 0.046). Age was only correlated with baseline chromium (rho = 0.373, P = 0.042). Being male was associated with baseline/follow-up nickel levels (P ≤ 0.030). SSC number was not correlated with ions or pH (P > 0.36). It was shown for the first time that SSCs might increase salivary nickel and chromium concentrations and reduce saliva acidity. Nickel increase might be in line with pH elevation. The raised pH might be associated with reduced chromium release. Boys might have higher nickel levels than might girls, with or without SSCs.

Microbiological profile and potential hazards associated with imported and local brands of tomato paste in Nigeria.

PubMed

Efiuvwevwere, B J; Atirike, O I

1998-03-01

Cans of three tomato paste brands (two of which are imported and one produced locally) showing defective or normal appearance were purchased from various retail outlets and analysed for microbial composition and pH values. Substantially higher total viable counts were observed in samples from defective cans but the lowest population was found in the local brand. Ratio of mesophilic to thermophilic micro-organisms increased in samples obtained from cans showing visible defects. Anaerobic spore counts were higher than the aerobic population in both normal and defective cans, but the counts varied with the brands. Four dominant bacterial genera (Bacillus, Clostridium, Lactobacillus and Leuconostoc) were isolated from the samples with the greater proportion being spore-formers. Percentage occurrence of Clostridium thermosaccharolyticum was appreciably higher in samples from defective cans while a preponderance of Lactobacillus occurred in samples from normal cans. Of the moulds isolated, Absidia and Aspergillus fumigatus showed a higher percentage in defective cans. pH values higher than the critical safe level of 4.6 were found in cans with visible defects and greater microbial diversity with higher microbial load was more often associated with these samples. Imported brands showed more undesirable microbial quality and pH values, making them potentially hazardous.

Effect of trace minerals and starch on digestibility and rumen fermentation in diets for dairy heifers.

PubMed

Pino, F; Heinrichs, A J

2016-04-01

The objective of this study was to evaluate the effect of different forms of trace minerals (TM) and the use of different starch levels in dairy heifer diets on rumen fermentation and digestibility. Eight rumen cannulated dairy heifers (15.4 ± 0.8 mo of age and 438.31 ± 18.08 kg of body weight) were subjected to a split-plot, 4 × 4 Latin square design with 19-d periods: 15d of adaptation and 4d of sampling. The whole-plot factor was type of TM; organic as proteinates (OTM) or inorganic sulfates (ITM), and the subplot was starch level (3.54, 12.95, 22.25, and 31.73%). Total collection of feces and urine was completed on d 15 to 19 to determine digestibility and TM excretion. Rumen contents were sampled on d 18 to 19 at 0, 1, 2, 4, 8, 12, 16, 20, and 22 h after feeding to measure pH and volatile fatty acid (VFA) concentrations. Plasma samples were collected to evaluate TM concentrations and enzymatic activity for ceruloplasmin, glutathione peroxidase, and superoxide dismutase. Starch level affected pH, individual VFA concentrations, and nutrient excretion. Trace mineral intake was lower for OTM compared with ITM. No effect of TM form on dry matter digestibility was detected, but as level of starch increased, diet dry matter digestibility increased. Rumen pH was lower for diets with OTM, which is consistent with higher total VFA production and butyrate proportion observed for heifers fed OTM diets. These variables may be explained by the higher bioavailability of OTM and faster utilization and fermentation by rumen microorganisms. Heifers that consumed ITM had higher moisture in feces and higher urine excretion, which increased total manure production. Total excretion of TM was not different by treatment. Blood plasma mineral concentration was not different between treatments except for Mn, which was higher for OTM. Enzymatic activity was not affected by treatments. Mineral intake was reduced and blood mineral levels were not different, suggesting enhanced absorption of OTM compared with ITM. In conclusion, based on rumen pH, VFA production, and plasma TM concentration, OTM may be more ruminally bioavailable and absorbed to a greater extent than ITM. Also, TM form affected fecal moisture and urine excretion, suggesting that ITM may stimulate water intake. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The effect of eubiotic feed additives on the performance of growing pigs and the activity of intestinal microflora.

PubMed

Nowak, Piotr; Kasprowicz-Potocka, Małgorzata; Zaworska, Anita; Nowak, Włodzimierz; Stefańska, Barbara; Sip, Anna; Grajek, Włodzimierz; Juzwa, Wojciech; Taciak, Marcin; Barszcz, Marcin; Tuśnio, Anna; Grajek, Katarzyna; Foksowicz-Flaczyk, Joanna; Frankiewicz, Andrzej

2017-12-01

The aim of this study was to compare the effect of probiotic bacteria, prebiotics, phytobiotics and their combinations on performance and microbial activity in the digestive tract of growing pigs. The experiment was conducted over 28 d on 48 male pigs of about 12 kg body weight (BW), which were allocated to following treatments.: (1) Control Group (Con) without additive, (2) Group I, addition of a prebiotic (inulin), (3) Group Ph, a phytobiotic (herbal water extracts), (4) Group P, a probiotic composed of four strains of lactic acid bacteria, (5) Group PhP, phytobiotic and probiotic bacteria and (6) Group PhPI, a phytobiotic, probiotic bacteria and a prebiotic. Animal performance was recorded and at d 28 six pigs from each group were euthanised to collect digesta samples. In all groups except for Group I, diarrhoea incidents were observed. Groups Ph and P had significantly higher daily gains and final BW, and Group Ph utilised feed better than other groups. The pH of ileal digesta was significantly lower in Group PhPI. In the caecal digesta of Groups I, P and PhP, the pH level was lower than in the other groups but dry matter contents was significantly higher in Groups Con and I. The short-chain fatty acids and particular acid content differed significantly only in the colonic digesta. The yeast and mould numbers in caecal digesta was highest in Group Con. No treatment effects were observed for the number of lactic acid bacteria, coli group bacteria or Clostridium. However, the observed significantly higher number of total bacteria suggests that a multi-component eubiotic treatment changes the bacterial composition and distribution more effectively. Our findings indicated that all used additives changed the intestinal microflora, but the multi-component eubiotics were not beneficial as feed additives offered separately. Moreover, supplementation of phytobiotics and probiotic bacteria also improved the animal performance significantly.

Experiences, behaviors, and perceptions of registered nurses regarding research ethics and misconduct.

PubMed

Asman, Oren; Melnikov, Semyon; Barnoy, Sivia; Tabak, Nili

2017-01-01

Nurses engaging in research are held to research ethics standards. Research aim: Examine experiences, behaviors, and perceptions of nurses in Israel regarding research ethics and explore possible related factors. An original investigator-designed self-administered questionnaire measured five variables: (a) ethics in research, (b) encountered research misconduct during the course of one's studies, (c) the inclination to fabricate data, (d) the inclination to select or omit data, and (e) knowledge of research misconduct in the workplace. Additionally, demographic data were collected. Participants and research context: The questionnaire was completed by 151 Israeli registered nurses. 10.2% hold a PhD, 34 % hold an MA, 42.2% hold a BA, and 13.6% with no academic degree. Ethical considerations: The study was approved by the University's ethics committee; anonymity and consent of the respondents were respected. Registered nurses' level of studies achieved was significantly associated with a lower inclination to fabricate data, with one exception-PhD nurses were more inclined to fabricate data than nurses with a Master's degree. A trend was found in which a higher level of studies is associated with higher knowledge of research misconduct in the workplace. Results indicate that nurses' perceptions of research ethics change throughout their academic studies, indicating a positive influence of level of studies, research experience, and work experience on ethics perceptions. Nevertheless, PhD nurses showed a greater inclination to actually select, omit, or even fabricate data than MA nurses. This may be related to pressure to publish. PhD nursing programs should include ethics training. Academic faculty members should serve as role models regarding research integrity. Research ethics deserves further emphasis on all levels of nurse education in Israel, as well as in the nurses' code of ethics and related documents. This may positively impact ethical research practices.

Vulnerability of Coral Reefs to Bioerosion From Land-Based Sources of Pollution

NASA Astrophysics Data System (ADS)

Prouty, Nancy G.; Cohen, Anne; Yates, Kimberly K.; Storlazzi, Curt D.; Swarzenski, Peter W.; White, Darla

2017-12-01

Ocean acidification (OA), the gradual decline in ocean pH and [CO32-] caused by rising levels of atmospheric CO2, poses a significant threat to coral reef ecosystems, depressing rates of calcium carbonate (CaCO3) production, and enhancing rates of bioerosion and dissolution. As ocean pH and [CO32-] decline globally, there is increasing emphasis on managing local stressors that can exacerbate the vulnerability of coral reefs to the effects of OA. We show that sustained, nutrient rich, lower pH submarine groundwater discharging onto nearshore coral reefs off west Maui lowers the pH of seawater and exposes corals to nitrate concentrations 50 times higher than ambient. Rates of coral calcification are substantially decreased, and rates of bioerosion are orders of magnitude higher than those observed in coral cores collected in the Pacific under equivalent low pH conditions but living in oligotrophic waters. Heavier coral nitrogen isotope (δ15N) values pinpoint not only site-specific eutrophication, but also a sewage nitrogen source enriched in 15N. Our results show that eutrophication of reef seawater by land-based sources of pollution can magnify the effects of OA through nutrient driven-bioerosion. These conditions could contribute to the collapse of coastal coral reef ecosystems sooner than current projections predict based only on ocean acidification.