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https://www.readbyqxmd.com/read/28102380/novel-high-temperature-ferroelectric-domain-morphology-in-pbtio3-ultrathin-films
#1
Jacob B J Chapman, Anna V Kimmel, Dorothy M Duffy
Exotic domain morphologies in ferroic materials are an exciting avenue for the development of novel nanoelectronics. In this work we have used large scale molecular dynamics to construct a strain-temperature phase diagram of the domain morphology of PbTiO3 ultrathin films. Sampling a wide interval of strain values over a temperature range up to the Curie temperature Tc, we found that epitaxial strain induces the formation of a variety of closure- and in-plane domain morphologies. The local strain and ferroelectric-antiferrodistortive coupling at the film surface vary for the strain mediated transition sequence and this could offer a route for experimental observation of the morphologies...
January 19, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28100018/conversion-of-amazon-rainforest-to-agriculture-alters-community-traits-of-methane-cycling-organisms
#2
Kyle M Meyer, Ann M Klein, Jorge L M Rodrigues, Klaus Nüsslein, Susannah G Tringe, Babur S Mirza, James M Tiedje, Brendan J M Bohannan
Land use change is one of the greatest environmental impacts worldwide, especially to tropical forests. The Amazon rainforest has been subject to particularly high rates of land use change, primarily to cattle pasture. A commonly observed response to cattle pasture establishment in the Amazon is the conversion of soil from a methane sink in rainforest, to a methane source in pasture. However, it is not known how the microorganisms that mediate methane flux are altered by land use change. Here we use the deepest metagenomic sequencing of Amazonian soil to date to investigate differences in methane-cycling microorganisms and their traits across rainforest and cattle pasture soils...
January 18, 2017: Molecular Ecology
https://www.readbyqxmd.com/read/28099473/the-staphylococcus-aureus-srrab-regulatory-system-modulates-hydrogen-peroxide-resistance-factors-which-imparts-protection-to-aconitase-during-aerobic-growth
#3
Ameya A Mashruwala, Jeffrey M Boyd
The SrrAB two-component regulatory system (TCRS) positively influences the transcription of genes involved in aerobic respiration in response to changes in respiratory flux. Hydrogen peroxide (H2O2) can arise as a byproduct of spontaneous interactions between dioxygen and components of respiratory pathways. H2O2 damages cellular factors including protein associated iron-sulfur cluster prosthetic groups. We found that a Staphylococcus aureus strain lacking the SrrAB two-component regulatory system (TCRS) is sensitive to H2O2 intoxication...
2017: PloS One
https://www.readbyqxmd.com/read/28098283/high-precision-localized-proton-gradients-and-fluxes-generated-by-a-microelectrode-device-induce-differential-growth-behaviors-of-pollen-tubes
#4
Chengzhi Hu, Hannes Vogler, Marianne Aellen, Naveen Shamsudhin, Bumjin Jang, Jan T Burri, Nino Läubli, Ueli Grossniklaus, Salvador Pané, Bradley J Nelson
Pollen tubes are tip-growing plant cells that deliver the sperm cells to the ovules for double fertilization of the egg cell and the endosperm. Various directional cues can trigger the reorientation of pollen tube growth direction on their passage through the female tissues. Among the external stimuli, protons serve an important, regulatory role in the control of pollen tube growth. The generation of local guidance cues has been challenging when investigating the mechanisms of perception and processing of such directional triggers in pollen tubes...
January 18, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28098273/high-definition-infrared-chemical-imaging-of-colorectal-tissue-using-a-spero-qcl-microscope
#5
B Bird, J Rowlette
Mid-infrared microscopy has become a key technique in the field of biomedical science and spectroscopy. This label-free, non-destructive technique permits the visualisation of a wide range of intrinsic biochemical markers in tissues, cells and biofluids by detection of the vibrational modes of the constituent molecules. Together, infrared microscopy and chemometrics is a widely accepted method that can distinguish healthy and diseased states with high accuracy. However, despite the exponential growth of the field and its research world-wide, several barriers currently exist for its full translation into the clinical sphere, namely sample throughput and data management...
January 18, 2017: Analyst
https://www.readbyqxmd.com/read/28097496/historical-trends-of-organochlorine-pesticides-ocps-recorded-in-sediments-across-the-tibetan-plateau
#6
Ruiqiang Yang, Ting Xie, Handong Yang, Simon Turner, Guangjian Wu
Sediment cores from four lakes across the Tibetan Plateau were used as natural archives to study the time trends of organochlorine pesticides (OCPs). The total concentrations of dichlorodiphenyltrichloroethane (ΣDDT) and hexachlorocyclohexane isomers (ΣHCH) were in the range of 0.04-1.61 and 0.08-1.88 ng/g based on dry weight (dw), while the input fluxes were in the range of 0.3-236 and 0.7-295 pg/cm(2)/y in the core sediments, respectively. The input fluxes of ΣDDT and ΣHCH generally peaked in sediment layers corresponding to the 1970s-1990s and peaked in top sediment layers...
January 17, 2017: Environmental Geochemistry and Health
https://www.readbyqxmd.com/read/28096127/formation-of-fructose-mediated-advanced-glycation-end-products-and-their-roles-in-metabolic-and-inflammatory-diseases
#7
REVIEW
Alejandro Gugliucci
Fructose is associated with the biochemical alterations that promote the development of metabolic syndrome (MetS), nonalcoholic fatty liver disease, and type 2 diabetes. Its consumption has increased in parallel with MetS. It is metabolized by the liver, where it stimulates de novo lipogenesis. The triglycerides synthesized lead to hepatic insulin resistance and dyslipidemia. Fructose-derived advanced glycation end products (AGEs) may be involved via the Maillard reaction. Fructose has not been a main focus of glycation research because of the difficulty in measuring its adducts, and, more importantly, because although it is 10 times more reactive than glucose, its plasma concentration is only 1% of that of glucose...
January 2017: Advances in Nutrition
https://www.readbyqxmd.com/read/28094920/antifouling-thin-film-composite-membranes-by-controlled-architecture-of-zwitterionic-polymer-brush-layer
#8
Caihong Liu, Jongho Lee, Jun Ma, Menachem Elimelech
In this study, we demonstrate a highly antifouling thin-film-composite (TFC) membrane by grafting a zwitterionic polymer brush via atom-transfer radical-polymerization (ATRP), a controlled, environmentally benign chemical process. Initiator molecules for polymerization were immobilized on the membrane surface by bio-inspired catechol chemistry, leading to the grafting of a dense zwitterionic polymer brush layer. Surface characterization revealed that the modified membrane exhibits reduced surface roughness, enhanced hydrophilicity, and lower surface charge...
January 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28094159/performance-of-polydimethylsiloxane-membrane-contactor-process-for-selective-hydrogen-sulfide-removal-from-biogas
#9
Ebrahim Tilahun, Alper Bayrakdar, Erkan Sahinkaya, Bariş Çalli
H2S in biogas affects the co-generation performance adversely by corroding some critical components within the engine and it has to be removed in order to improve the biogas quality. This work presents the use of polydimethylsiloxane (PDMS) membrane contactor for selective removal of H2S from the biogas. Experiments were carried out to evaluate the effects of different pH of absorption liquid, biogas flowrate and temperature on the absorption performances. The results revealed that at the lowest loading rate (91mg H2S/m(2)·h) more than 98% H2S and 59% CO2 absorption efficiencies were achieved...
January 13, 2017: Waste Management
https://www.readbyqxmd.com/read/28093899/crucial-role-of-donor-density-in-the-performance-of-oxynitride-perovskite-latio2n-for-photocatalytic-water-oxidation-reaction
#10
Feng-Qiang Xiong, Lipeng Wan, Yue Li, Tiju Thomas, Francis Joseph DiSalvo, Minghui Yang
LaTiO2N photocatalysts were prepared via thermal ammonalysis of flux-synthesized La2Ti2O7 and La2TiO5, and were investigated for water oxidation. Though LaTiO2N derived from La2TiO5 appears defect-free in UV-Vis-NIR and electron paramagnetic resonance spectroscopies, its performance is much lower than conventional La2Ti2O7-derived LaTiO2N with defects. It is shown by Mott-Schottky analysis that La2TiO5-derived LaTiO2N has significantly lower donor density; this can result in insufficient build-in electric field for the separation of photogenerated electrons and holes...
January 17, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28093405/distributedfba-jl-high-level-high-performance-flux-balance-analysis-in-julia
#11
Laurent Heirendt, Ines Thiele, Ronan M T Fleming
MOTIVATION: Flux balance analysis, and its variants, are widely used methods for predicting steady-state reaction rates in biochemical reaction networks. The exploration of high dimensional networks with such methods is currently hampered by software performance limitations. RESULTS: DistributedFBA.jl is a high-level, high-performance, open-source implementation of flux balance analysis in Julia. It is tailored to solve multiple flux balance analyses on a subset or all the reactions of large and huge-scale networks, on any number of threads or nodes...
January 16, 2017: Bioinformatics
https://www.readbyqxmd.com/read/28092951/cuso4-h2o2-triggered-polydopamine-poly-sulfobetaine-methacrylate-coatings-for-antifouling-membrane-surfaces
#12
Chao Zhang, Hao-Nan Li, Yong Du, Meng-Qi Ma, Zhi-Kang Xu
The mussel-inspired polydopamine (PDA) coatings have been broadly exploited for constructing functional membrane surfaces. One-step co-deposition of PDA with antifouling polymers, especially zwitterionic polymer, has been regarded as a promising strategy for fabricating antifouling membrane surfaces. However, one challenge is that the co-deposition is usually a slow process with ten hours or even several days. Herein, we report that CuSO4/H2O2 is able to notably accelerate the co-deposition process of PDA with poly(sulfobetaine methacrylate) (PSBMA)...
January 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28092823/ph-lactate-and-hypoxia-reciprocity-in-regulating-high-affinity-monocarboxylate-transporter-expression-in-glioblastoma
#13
James P Caruso, Brandon J Koch, Philip D Benson, Elsa Varughese, Michael D Monterey, Amy E Lee, Ajal M Dave, Sam Kiousis, Andrew E Sloan, Saroj P Mathupala
Highly malignant brain tumors harbor the aberrant propensity for aerobic glycolysis, the excessive conversion of glucose to lactic acid even in the presence of ample tissue oxygen. Lactic acid is rapidly effluxed to the tumor microenvironment via a group of plasma-membrane transporters denoted monocarboxylate transporters (MCTs) to prevent "self-poisoning." One isoform, MCT2, has the highest affinity for lactate and thus should have the ability to respond to microenvironment conditions such as hypoxia, lactate, and pH to help maintain high glycolytic flux in the tumor...
January 13, 2017: Neoplasia: An International Journal for Oncology Research
https://www.readbyqxmd.com/read/28092746/supranutritional-selenium-intake-from-enriched-milk-casein-impairs-hepatic-insulin-sensitivity-via-attenuated-irs-pi3k-akt-signaling-and-decreased-pgc-1%C3%AE-expression-in-male-sprague-dawley-rats
#14
Priska Stahel, Julie J Kim, Scott R L Cieslar, Jenny M Warrington, Changting Xiao, John P Cant
Selenium (Se)-enriched milk provides antioxidant benefits and has therapeutic potential against cancer. However, both antidiabetic and prodiabetic effects have been attributed to Se. Our objective was to evaluate the effect of Se-enriched milk casein on insulin sensitivity in rats when given at the requirement of 0.25 ppm Se and supranutritionally on both low- and high-fat diets. Two hundred sixteen male Sprague-Dawley rats were fed low- or high-fat diets containing one, two or eight times the Se requirement in a randomized block design...
January 7, 2017: Journal of Nutritional Biochemistry
https://www.readbyqxmd.com/read/28092678/6-phosphofructo-2-kinase-fructose-2-6-biphosphatase-4-is-essential-for-p53-null-cancer-cells
#15
S Ros, J Flöter, I Kaymak, C Da Costa, A Houddane, S Dubuis, B Griffiths, R Mitter, S Walz, S Blake, A Behrens, K M Brindle, N Zamboni, M H Rider, A Schulze
The bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-4 (PFKFB4) controls metabolic flux through allosteric regulation of glycolysis. Here we show that p53 regulates the expression of PFKFB4 and that p53-deficient cancer cells are highly dependent on the function of this enzyme. We found that p53 downregulates PFKFB4 expression by binding to its promoter and mediating transcriptional repression via histone deacetylases. Depletion of PFKFB4 from p53-deficient cancer cells increased levels of the allosteric regulator fructose-2,6-bisphosphate, leading to increased glycolytic activity but decreased routing of metabolites through the oxidative arm of the pentose-phosphate pathway...
January 16, 2017: Oncogene
https://www.readbyqxmd.com/read/28092384/emerging-investigator-series-a-14-year-depositional-ice-record-of-perfluoroalkyl-substances-in-the-high-arctic
#16
John J MacInnis, Katherine French, Derek C G Muir, Christine Spencer, Alison Criscitiello, Amila O De Silva, Cora J Young
To improve understanding of long-range transport of perfluoroalkyl substances to the High Arctic, samples were collected from a snow pit on the Devon Ice Cap in spring 2008. Snow was analyzed for perfluoroalkyl acids (PFAAs), including perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs), as well as perfluorooctane sulfonamide (FOSA). PFAAs were detected in all samples dated from 1993 to 2007. PFAA fluxes ranged from <1 to hundreds of ng per m(2) per year. Flux ratios of even-odd PFCA homologues were mostly between 0...
January 16, 2017: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/28089399/a-mass-balance-model-to-estimate-the-rate-of-composting-methane-oxidation-and-anaerobic-digestion-in-soil-covers-and-shallow-waste-layers
#17
Reza Rafiee, Lizanne Obersky, Sihuang Xie, William P Clarke
Although CH4 oxidation in landfill soil covers is widely studied, the extent of composting and CH4 oxidation in underlying waste layers has been speculated but not measured. The objective of this study was to develop and validate a mass balance model to estimate the simultaneous rates of anaerobic digestion (rAD), CH4 oxidation (rOX) and composting (rCOM) in environments where O2 penetration is variable and zones of aerobic and anaerobic activity are intermingled. The modelled domain could include, as an example, a soil cover and the underlying shallow waste to a nominated depth...
January 12, 2017: Waste Management
https://www.readbyqxmd.com/read/28088694/metabolic-network-modeling-with-model-organisms
#18
REVIEW
L Safak Yilmaz, Albertha Jm Walhout
Flux balance analysis (FBA) with genome-scale metabolic network models (GSMNM) allows systems level predictions of metabolism in a variety of organisms. Different types of predictions with different accuracy levels can be made depending on the applied experimental constraints ranging from measurement of exchange fluxes to the integration of gene expression data. Metabolic network modeling with model organisms has pioneered method development in this field. In addition, model organism GSMNMs are useful for basic understanding of metabolism, and in the case of animal models, for the study of metabolic human diseases...
January 12, 2017: Current Opinion in Chemical Biology
https://www.readbyqxmd.com/read/28088059/infrared-analysis-of-clay-bricks-incorporated-with-spent-shea-waste-from-the-shea-butter-industry
#19
A N Adazabra, G Viruthagiri, N Shanmugam
The peculiar challenge of effective disposing abundant spent shea waste and the excellent compositional variation tolerance of clay material offered an impetus to examine the incorporation of spent shea waste into clay material as an eco-friendly disposal route in making clay bricks. For this purpose, the chemical constituent, mineralogical compositions and thermal behavior of both clay material and spent shea waste were initially characterized from which modelled brick specimens incorporating 5-20 wt% of the waste into the clay material were prepared...
January 11, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28081508/historical-variation-in-black-carbon-deposition-and-sources-to-northern-china-sediments
#20
Wenxue Xu, Fu Wang, Jiwei Li, Lizhu Tian, Xingyu Jiang, Jilong Yang, Bing Chen
Black carbon (BC) in fine particulate matter (PM2.5) is an important air pollutant in a large area of China. We have reconstructed a 100-year-long history of BC deposition based on analyses of sediment samples in the coastal area of the Northern China Plain (NCP). During 1900-2010, the sedimentary BC concentrations at three cores increased from 0.2 to 1.3, from 0.2 to 2.3, and from 0.2 to 1.9 mg g(-1), and the ranges for the BC deposition fluxes were 0.1-4.7, 0.1-8.2, 0.2-7.4 g m(-2) a(-1), suggesting the increase of ten times from the pre-industrial era...
January 2, 2017: Chemosphere
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