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Buffer capacity

Carlos Sanhueza, Joaquín Araos, Luciano Naranjo, Fernando Toledo, Ana R Beltrán, Marco A Ramírez, Jaime Gutiérrez, Fabián Pardo, Andrea Leiva, Luis Sobrevia
Cancer cells generate protons (H(+)) that are extruded to the extracellular medium mainly via the Na(+)/H(+) exchanger 1 (NHE1), which regulates intracellular pH (pHi) and cell proliferation. In primary cultures of human ascites-derived ovarian cancer cells (haOC) we assayed whether NHE1 was required for pHi modulation and cell proliferation. Human ovary expresses NHE1, which is higher in haOC and A2780 (ovarian cancer cells) compared with HOSE cells (normal ovarian cells). Basal pHi and pHi recovery (following a NH4Cl pulse) was higher in haOC and A2780, compared with HOSE cells...
October 21, 2016: Biochimica et Biophysica Acta
Allegra T Aron, Morten O Loehr, Jana Bogena, Christopher J Chang
Iron is essential for sustaining life, as its ability to cycle between multiple oxidation states is critical for catalyzing chemical transformations in biological systems. However, without proper regulation, this same redox capacity can trigger oxidative stress events that contribute to aging along with diseases ranging from cancer to cardiovascular and neurodegenerative disorders. Despite its importance, methods for monitoring biological iron bound weakly to cellular ligands-the labile iron pool-to generate a response that preserves spatial and temporal information remain limited, owing to the potent fluorescence quenching ability of iron...
October 21, 2016: Journal of the American Chemical Society
Jinlong Cui, Yongfu Cui, Shaohui Li, Hongliang Sun, Zhongsheng Wen, Juncai Sun
Micro-sized porous SiOx@C composites used as anode for lithium-ion batteries (LIBs) are synthesized from rice husks (RHs) through low-temperature (700 °C) aluminothermic reduction. The resulting SiOx@C composite shows mesoporous irregular particle morphology with a high specific surface area of 597.06 m2/g under the optimized reduction time. This porous SiOx@C composite is constructed by SiOx nanoparticles uniformly dispersed in the C matrix. When tested as anode material for LIBs, it displays considerable specific capacity (1230 mAh/g at a current density of 0...
October 20, 2016: ACS Applied Materials & Interfaces
Christian Demitri, Antonella Giuri, Vincenzo Maria De Benedictis, Maria Grazia Raucci, Daniela Giugliano, Alessandro Sannino, Luigi Ambrosio
In this study, a new foaming method, based on physical foaming combined with microwave-induced curing, is proposed in combination with a surface bioactivation to develop scaffold for bone tissue regeneration. In the first step of the process, a stable physical foaming was induced using a surfactant (Pluronic) as blowing agent of a homogeneous blend of Chitosan and polyethylene glycol diacrylate (PEGDA700) solutions. In the second step, the porous structure of the foaming was chemically stabilized by radical polymerization induced by homogeneous heating of the sample in a microwave reactor...
October 20, 2016: Journal of Tissue Engineering and Regenerative Medicine
Charlotte A Jørgensen, Henning S Jensen, Sara Egemose
Measures such as stormwater ponds, constructed wetlands and buffer strips along streams are used to reduce diffuse phosphorus (P) loading to surface waters. These systems often retain particulate P well, whereas retention of dissolved P is less efficient and might require addition of P adsorbents. In this study, we screened waterwork ochre sludge (WWS) originating from groundwater treatment and ochre sludge from ochre precipitation basins along streams for their applicability as P adsorbents at ambient P concentrations...
October 19, 2016: Environmental Technology
Markus Gerber, Katharina Endes, Christian Herrmann, Flora Colledge, Serge Brand, Lars Donath, Oliver Faude, Uwe Pühse, Henner Hanssen, Lukas Zahner
PURPOSE: A better understanding of how social and environmental contexts impact on childhood overweight/obesity is needed to develop more effective prevention strategies. Because the relationship between physical activity, stress and obesity measures has received limited attention, this study examined for the first time in first grade schoolchildren whether physical activity and fitness moderate the relationship between psychosocial stress and obesity-related measures. METHODS: 325 children (51% girls, Mage=7...
October 14, 2016: Medicine and Science in Sports and Exercise
Alberto Avolio
Blood vessels function as conduits for distribution of blood throughout the circulatory system. Large arteries, in addition to the essential conduit function, also serve to dampen the effect of pulsatile ventricular ejection that generates pulsatile pressure with each cardiac cycle; that is, they exhibit a 'cushion' function. The conduit function can be compromised by intimal effects that cause obstruction to flow, generally attributed to plaque formation due to intimal changes affected by atherosclerotic processes...
September 2016: Journal of Hypertension
Yong Li, Xu Wang, Jie Yang, Xilei Xie, Mengmeng Li, Jinye Niu, Lili Tong, Bo Tang
Carbon monoxide (CO), a crucial gas message molecule, plays an important role in the regulation of physiological and pathological process. Hypoxia-induced CO is involved in modulating various cellular activities, including signal transduction, proliferation, and apoptosis. However, tracking CO fluctuation in the hypoxic cells is still a challenge due to lack of straight forward, visualized and non-invasive tools. In this work, based on metal palladium-catalyzed reaction, we present the rational design, synthesis and biological utility of an azobenzene-cyclopalladium-based fluorescent probe, ACP-2, for CO monitoring...
October 17, 2016: Analytical Chemistry
Thomas Wyss, Maria Boesch, Lilian Roos, Céline Tschopp, Klaus M Frei, Hubert Annen, Roberto La Marca
BACKGROUND: Good physical fitness seems to help the individual to buffer the potential harmful impact of psychosocial stress on somatic and mental health. The aim of the present study is to investigate the role of physical fitness levels on the autonomic nervous system (ANS; i.e. heart rate and salivary alpha amylase) responses to acute psychosocial stress, while controlling for established factors influencing individual stress reactions. METHODS: The Trier Social Stress Test for Groups (TSST-G) was executed with 302 male recruits during their first week of Swiss Army basic training...
December 2016: Sports Medicine—Open
Antonius Ljj Bronckers, Donacian M Lyaruu
Supraoptimal intake of fluoride (F) induces structural defects in forming enamel, dentin and bone and increases the risk of bone fractures. Enamel formation is most sensitive to low levels of F and the degree of enamel fluorosis depends on the mouse strain. What molecular mechanism is responsible for these differences in sensitivity is unclear. Maturation ameloblasts transport bicarbonates into enamel in exchange for Cl- to buffer protons released by forming apatites. We proposed that F-enhanced mineral deposition releases excess of protons that will affect mineralization in forming enamel...
October 12, 2016: Bone
Cian McGinley, David John Bishop
This study measured the adaptive response to exercise training for each of the acid/base transport protein families, including providing isoform-specific evidence for the monocarboxylate transporter (MCT)1/4 chaperone protein basigin and for the electrogenic sodium/bicarbonate cotransporter (NBCe)1. We investigated whether 4 weeks of work-matched, high-intensity interval training (HIIT), performed either just above the lactate threshold (HIITΔ20; n = 8), or close to peak aerobic power (HIITΔ90; n = 8), influenced adaptations in acid/base transport protein abundance, non-bicarbonate muscle buffer capacity (βmin vitro), and exercise capacity in active men...
October 14, 2016: Journal of Applied Physiology
Ashkan Madadlou, Siobhan O'Sullivan, David Sheehan
Fast protein liquid chromatography (FPLC) is a form of high-performance chromatography that takes advantage of the high resolution made possible by small-diameter stationary phases. It was originally developed for proteins and features high loading capacity, biocompatible aqueous buffer systems, fast flow rates, and availability of stationary phases in most common chromatography modes (e.g., ion exchange, gel filtration, reversed phase, and affinity). The system makes reproducible separation possible by incorporating a high level of automation including autosamplers, gradient program control, and peak collection...
2017: Methods in Molecular Biology
Jonathan B Armstrong, Eric J Ward, Daniel E Schindler, Peter J Lisi
As climate change increases maximal water temperatures, behavioural thermoregulation may be crucial for the persistence of coldwater fishes, such as salmonids. Although myriad studies have documented behavioural thermoregulation in southern populations of salmonids, few if any have explored this phenomenon in northern populations, which are less likely to have an evolutionary history of heat stress, yet are predicted to experience substantial warming. Here, we treated a rare heat wave as a natural experiment to test whether wild sockeye salmon (Oncorhynchus nerka) at the northern extent of their primary range (60° latitude) can thermoregulate in response to abnormally high thermal conditions...
2016: Conservation Physiology
Jonathan L Payne, Andrew M Bush, Ellen T Chang, Noel A Heim, Matthew L Knope, Sara B Pruss
The macroevolutionary effects of extinction derive from both intensity of taxonomic losses and selectivity of losses with respect to ecology, physiology and/or higher taxonomy. Increasingly, palaeontologists are using logistic regression to quantify extinction selectivity because the selectivity metric is independent of extinction intensity and multiple predictor variables can be assessed simultaneously. We illustrate the use of logistic regression with an analysis of physiological buffering capacity and extinction risk in the Phanerozoic marine fossil record...
October 2016: Biology Letters
Shuling Liu, Xiaodong He, Jianping Zhu, Liqiang Xu, Jianbo Tong
Cu3P/reduced graphene oxide (Cu3P/RGO) nanocomposite was successfully synthesized by a facile one-pot method as an advanced anode material for high-performance lithium-ion batteries. Cu3P nanostructures with a polyhedral shape with the mean diameter (80-100 nm) were homogeneously anchored on the surface of RGO. The flexible RGO sheets acted as elastic buffering layer which not only reduced the volume change, but also prevented the aggregation of Cu3P nanostructures, the cracking and crumbing of electrodes...
October 11, 2016: Scientific Reports
Elías Obreque-Slier, Valeria Espínola-Espínola, Remigio Omar López-Solís
Wine is an acidic beverage whose pH (2.9-3.8) is critically important to its organoleptic properties. During degustation, wine interacts with less than 1 mL of mouth saliva whose pH is near 7.0. This is buffered predominantly by the carbonate/bicarbonate pair (pKa 6.1). Not much data is available on whether the buffering capacity of saliva may alter the pH of wine and thus its sensorial properties. In this study both in vitro and in vivo approaches were conducted to measure pH in mixtures of representative red and white wines with human saliva...
October 11, 2016: Journal of Agricultural and Food Chemistry
Jesper Givskov Sørensen, Torsten Nygaard Kristensen, Johannes Overgaard
Phenotypic plasticity of temperature tolerance (thermal acclimation) is often highlighted as an important component of the acute and evolutionary adaptation to temperatures in insects. For this reason, it is often suggested that thermal acclimation ability could be important for buffering the consequences of climate change. Based on data from Drosophila we discuss if and how phenotypic plasticity is likely to mitigate the effects of climate change. We conclude that plasticity of upper thermal limits is small in magnitude, evolves slowly and that acclimation ability is weakly correlated with latitude and environmental heterogeneity...
October 2016: Current Opinion in Insect Science
Gaoxiang Qi, Lian Xiong, Xiaoqing Lin, Chao Huang, Hailong Li, Xuefang Chen, Xinde Chen
OBJECTIVE: To investigate the inhibiting effect of formic acid on acetone/butanol/ethanol (ABE) fermentation and explain the mechanism of the alleviation in the inhibiting effect under CaCO3 supplementation condition. RESULTS: From the medium containing 50 g sugars l(-1) and 0.5 g formic acid l(-1), only 0.75 g ABE l(-1) was produced when pH was adjusted by KOH and fermentation ended prematurely before the transformation from acidogenesis to solventogenesis. In contrast, 11...
October 6, 2016: Biotechnology Letters
Félix Landry Yuan, Evan J Pickett, Timothy C Bonebrake
Susceptibility of species to climate change varies depending on many biological and environmental traits, such as reproductive mode and climatic exposure. For example, wider thermal tolerance breadths are associated with more climatically variable habitats and viviparity could be associated with greater vulnerability relative to oviparity. However, few examples exist detailing how such physiological and environmental traits together might shape species thermal performance. In this study we compared the thermal tolerance and performance of two sympatric skink congeners in Hong Kong that differ in habitat use and reproductive mode...
October 2016: Journal of Thermal Biology
Niko C Bock, Laura Seibold, Christian Heumann, Erhard Gnandt, Miriam Röder, Sabine Ruf
BACKGROUND: White spot lesions (WSL) frequently occur as side-effect of multibracket appliance treatment. The clinical effects of local fluoridation on post-orthodontic WSL and oral health development are however inconclusive. OBJECTIVE: In vivo monitoring of clinical WSL and oral health changes in response to weekly 1.25 per cent fluoride gel application after multibracket appliance treatment. TRIAL DESIGN: Randomized, single-centre, double-blind, parallel-group, placebo-controlled study...
October 4, 2016: European Journal of Orthodontics
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