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https://www.readbyqxmd.com/read/27917399/retinoids-and-retinal-diseases
#1
Philip D Kiser, Krzysztof Palczewski
Recent progress in molecular understanding of the retinoid cycle in mammalian retina stems from painstaking biochemical reconstitution studies supported by natural or engineered animal models with known genetic lesions and studies of humans with specific genetic blinding diseases. Structural and membrane biology have been used to detect critical retinal enzymes and proteins and their substrates and ligands, placing them in a cellular context. These studies have been supplemented by analytical chemistry methods that have identified small molecules by their spectral characteristics, often in conjunction with the evaluation of models of animal retinal disease...
October 2016: Annual Review of Vision Science
https://www.readbyqxmd.com/read/27916134/underway-analysis-of-nanomolar-dissolved-reactive-phosphorus-in-oligotrophic-seawater-with-automated-on-line-solid-phase-extraction-and-spectrophotometric-system
#2
Jian Ma, Yuan Yuan, Dongxing Yuan
The automated in-field determination of trace phosphate (and other nutrients) is highly valuable for studying nutrient dynamics and cycling in oligotrophic oceans. Here, we report an automated portable analyzer for week-long underway analysis of nanomolar dissolved reactive phosphorus (DRP) in seawater. The method is based on classic phosphomolybdenum blue (PMB) chemistry combined with on-line solid phase extraction (SPE) and flow analysis. Under optimized conditions, the formed PMB from sample is automatically concentrated on a hydrophilic lipophilic balanced (HLB) copolymer SPE...
January 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/27899239/avoid-the-pcb-mistakes-a-more-sustainable-future-for-ionic-liquids
#3
REVIEW
Gregory Chatel, Emmanuel Naffrechoux, Micheline Draye
Based on our original knowledge and experience on both polychlorinated biphenyls (PCBs) identification in aquatic ecosystems, and use of ionic liquids (ILs) as solvents and/or co-catalysts in green chemistry, we drawn a dared comparison between these two families. Indeed, PCBs has been used during several decades for their new properties, but are now considered as prevalent and persistent pollutants; some toxic effects on environment or human are still revealed. ILs, often designated as "green solvents" are increasingly used in numerous applications, but few studies reported about their environmental impact are still controversial...
November 21, 2016: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/27891118/colistin-in-pig-production-chemistry-mechanism-of-antibacterial-action-microbial-resistance-emergence-and-one-health-perspectives
#4
REVIEW
Mohamed Rhouma, Francis Beaudry, William Thériault, Ann Letellier
Colistin (Polymyxin E) is one of the few cationic antimicrobial peptides commercialized in both human and veterinary medicine. For several years now, colistin has been considered the last line of defense against infections caused by multidrug-resistant Gram-negative such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Colistin has been extensively used orally since the 1960s in food animals and particularly in swine for the control of Enterobacteriaceae infections. However, with the recent discovery of plasmid-mediated colistin resistance encoded by the mcr-1 gene and the higher prevalence of samples harboring this gene in animal isolates compared to other origins, livestock has been singled out as the principal reservoir for colistin resistance amplification and spread...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27885032/directed-evolution-of-cytochrome-c-for-carbon-silicon-bond-formation-bringing-silicon-to-life
#5
S B Jennifer Kan, Russell D Lewis, Kai Chen, Frances H Arnold
Enzymes that catalyze carbon-silicon bond formation are unknown in nature, despite the natural abundance of both elements. Such enzymes would expand the catalytic repertoire of biology, enabling living systems to access chemical space previously only open to synthetic chemistry. We have discovered that heme proteins catalyze the formation of organosilicon compounds under physiological conditions via carbene insertion into silicon-hydrogen bonds. The reaction proceeds both in vitro and in vivo, accommodating a broad range of substrates with high chemo- and enantioselectivity...
November 25, 2016: Science
https://www.readbyqxmd.com/read/27877895/visible-tunable-lighting-system-based-on-polymer-composites-embedding-zno-and-metallic-clusters-from-colloids-to-thin-films
#6
Thai Giang Truong, Benjamin Dierre, Fabien Grasset, Noriko Saito, Norio Saito, Thi Kim Ngan Nguyen, Kohsei Takahashi, Tetsuo Uchikoshi, Marian Amela-Cortes, Yann Molard, Stéphane Cordier, Naoki Ohashi
The development of phosphor devices free of heavy metal or rare earth elements is an important issue for environmental reasons and energy efficiency. Different mixtures of ZnO nanocrystals with Cs2Mo6I8(OOC2F5)6 cluster compound (CMIF) dispersed into polyvinylpyrrolidone matrix have been prepared by very simple and low cost solution chemistry. The resulting solutions have been used to fabricate highly transparent and luminescent films by dip coating free of heavy metal or rare earth elements. The luminescence properties of solution and dip-coated films were investigated...
2016: Science and Technology of Advanced Materials
https://www.readbyqxmd.com/read/27876419/assessing-the-potential-of-inorganic-anions-cl-no3-so4-2-and-po4-3-to-increase-the-bioaccessibility-of-emitted-palladium-in-the-environment-experimental-studies-with-soils-and-a-pd-model-substance
#7
Fathi Zereini, Clare L S Wiseman, Jana Poprizki, Peter Albers, Wolfgang Schneider, Kerstin Leopold
Palladium (Pd) emitted from vehicles equipped with exhaust catalytic converters has been accumulating at a greater rate relative to other platinum group elements (PGE) in the last 10-20 years. Little is known, however, regarding the various environmental factors and conditions which are likely to modulate the chemical behavior and bioaccessibility of this element post-emission. To meet data needs, soils and a Pd model substance were treated with solutions containing common anions (Cl(-), NO3(-), SO4(2-) und PO4(3-)) to shed light on the geochemical behavior of emitted Pd under ambient conditions...
January 2017: Environmental Pollution
https://www.readbyqxmd.com/read/27876224/microenvironmental-air-quality-impact-of-a-commercial-scale-biomass-heating-system
#8
Zheming Tong, Bo Yang, Philip K Hopke, K Max Zhang
Initiatives to displace petroleum and climate change mitigation have driven a recent increase in space heating with biomass combustion. However, there is ample evidence that biomass combustion emits significant quantities of health damaging pollutants. We investigated the near-source micro-environmental air quality impact of a biomass-fueled combined heat and power system equipped with an electrostatic precipitator (ESP) in Syracuse, NY. Two rooftop sampling stations with PM2.5 and CO2 analyzers were established in such that one could capture the plume while the other one served as the background for comparison depending on the wind direction...
January 2017: Environmental Pollution
https://www.readbyqxmd.com/read/27871373/design-and-production-of-antibodies-for-the-detection-of-streptococcus-uberis
#9
K Mihklepp, K Kivirand, M Nikopensius, D Peedel, M Utt, T Rinken
Streptococcus uberis (S. uberis) is an important environmental pathogen causing mastitis in dairy cattle. Mastitis or mammary gland infection is the most common disease in milking cows and cause significant economic burden to farmers due to the reduction of the amount of milk and its quality. The development of rapid analytical methods for the determination of mastitis-causing pathogens in milk is of utmost importance for the early identification of the causes of mastitis and the beginning of timely treatment of cows...
January 2017: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/27871089/water-balance-creates-a-threshold-in-soil-ph-at-the-global-scale
#10
E W Slessarev, Y Lin, N L Bingham, J E Johnson, Y Dai, J P Schimel, O A Chadwick
Soil pH regulates the capacity of soils to store and supply nutrients, and thus contributes substantially to controlling productivity in terrestrial ecosystems. However, soil pH is not an independent regulator of soil fertility-rather, it is ultimately controlled by environmental forcing. In particular, small changes in water balance cause a steep transition from alkaline to acid soils across natural climate gradients. Although the processes governing this threshold in soil pH are well understood, the threshold has not been quantified at the global scale, where the influence of climate may be confounded by the effects of topography and mineralogy...
November 21, 2016: Nature
https://www.readbyqxmd.com/read/27867215/resolving-large-scale-pressures-on-species-and-ecosystems-propensity-modelling-identifies-agricultural-effects-on-streams
#11
Caitlin E Pearson, Steve J Ormerod, William O C Symondson, Ian P Vaughan
Although agriculture is amongst the world's most widespread land uses, studies of its effects on stream ecosystems are often limited in spatial extent. National monitoring data could extend spatial coverage and increase statistical power, but present analytical challenges where covarying environmental variables confound relationships of interest.Propensity modelling is used widely outside ecology to control for confounding variables in observational data. Here, monitoring data from over 3000 English and Welsh river reaches are used to assess the effects of intensive agricultural land cover (arable and pastoral) on stream habitat, water chemistry and invertebrates, using propensity scores to control for potential confounding factors (e...
April 2016: Journal of Applied Ecology
https://www.readbyqxmd.com/read/27866744/role-of-solution-chemistry-in-the-retention-and-release-of-graphene-oxide-nanomaterials-in-uncoated-and-iron-oxide-coated-sand
#12
Dengjun Wang, Chongyang Shen, Yan Jin, Chunming Su, Lingyang Chu, Dongmei Zhou
Understanding the fate and transport including remobilization of graphene oxide nanomaterials (GONMs) in the subsurface would enable us to expedite their benign use and evaluate their environmental impacts and health risks. In this study, the retention and release of GONMs were investigated in water-saturated columns packed with uncoated sand (Un-S) or iron oxide-coated sand (FeS) at environmentally relevant solution chemistries (1-100mM KCl and 0.1-10mM CaCl2 at pH7 and 11). Our results showed that increasing ionic strength (IS) inhibited GONMs' transport, and the impact of K(+) was less than Ca(2+)...
November 17, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27866605/hydrothermal-preparation-of-reduced-graphene-oxide-silver-nanocomposite-using-plectranthus-amboinicus-leaf-extract-and-its-electrochemical-performance
#13
Yuhong Zheng, Aiwu Wang, Wen Cai, Zhong Wang, Feng Peng, Zhong Liu, Li Fu
Graphene based nanocomposites are receiving increasing attention in many fields such as material chemistry, environmental science and pharmaceutical science. In this study, a facial synthesis of a reduced graphene oxide-silver nanocomposite (RGO-Ag) was carried out from Plectranthus amboinicus leaf extract. The synthesized nanocomposite was characterized by using X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscope and UV-vis spectroscopy for structural confirmation...
December 2016: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/27864584/reminiscence-of-forty-years-of-environmental-chemistry
#14
EDITORIAL
Vladimir Zitko
No abstract text is available yet for this article.
December 2016: Bulletin of Environmental Contamination and Toxicology
https://www.readbyqxmd.com/read/27858028/hydrazine-5-5-bitetrazole-1-1-diolate-a-promising-high-density-energetic-salt-with-good-properties
#15
Zhi-Bin Zhang, Cai-Xia Xu, Xin Yin, Jian-Guo Zhang
The development of new environmentally friendly energetic compounds with reasonable detonation performance and safety is a long-term target in energetic materials research. A new energetic eco-friendly salt of hydrazine 5,5'-bitetrazole-1,1'-diolate (HA·BTO) is developed based on the reaction of 1H,1'H-5,5'-bitetrazole-1,1'-diolate (BTO) with hydrazine hydrochloride (HA·HCl), and fully characterized. The monocrystal of the title salt is obtained and the structure is determined by powder X-ray diffraction and single crystal X-ray diffraction...
November 18, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/27856513/analytical-abf-stem-imaging-of-li-ions-in-rechargeable-batteries
#16
REVIEW
Yuren Wen, Tongtong Shang, Lin Gu
Rechargeable batteries are being intensively investigated in an attempt to solve the energy issues while meeting the environmental demands. Even though Li-ion batteries (LIB) with high energy and light weight have been commercialized within the last 20 years, these devices currently require higher energy density, output power and sustainability characteristics. The atomic behavior of Li ion that determines LIB's performance is hardly characterized by transmission electron microscopy (TEM) owing to its weak electron-scattering power...
November 17, 2016: Microscopy
https://www.readbyqxmd.com/read/27856300/hemin-utilizing-g-quadruplex-dnazymes-are-strongly-active-in-organic-co-solvents
#17
Thomas D Canale, Dipankar Sen
The widespread use of organic solvents in industrial processes has focused in recent years on the utility of "green" solvents - those with less harmful environmental, health, and safety properties - such as methanol and formamide. However, protein enzymes, regarded as green catalysts, are often incompatible with organic solvents. Herein, we have explored the oxidative properties of a Fe(III)-heme, or hemin, utilizing catalytic DNA (heme·DNAzyme) in different green solvent-water mixtures. We find that the peroxidase and peroxygenase activities of the heme·DNAzyme are strongly enhanced in 20-30% v/v methanol or formamide, relative to water alone...
November 14, 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/27853966/remediation-of-cu-metal-induced-accelerated-fenton-reaction-by-potato-peels-bio-sorbent
#18
Rafia Azmat, Sumeira Moin, Ailyan Saleem
This article has allied exposure to Ecological Particulate Matter (EPM) and its remediation using potato peel surface (PPC) bio-sorbent on two important edible crops Spinacia oleracea and Luffa acutangula. Fenton reaction acceleration was one of the major stress oxidation reactions as a consequence of iron and copper toxicity, which involve in the formation of hydroxyl radical (OH) through EPM. Results showed that the oxidative stress encouraged by Cu in both species that recruits the degradation of photosynthetic pigments, initiating decline in growth, reduced leaf area and degrade proteins...
December 0: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/27848090/environmental-geochemistry-of-the-abandoned-mamut-copper-mine-sabah-malaysia
#19
Antony van der Ent, Mansour Edraki
The Mamut Copper Mine (MCM) located in Sabah (Malaysia) on Borneo Island was the only Cu-Au mine that operated in the country. During its operation (1975-1999), the mine produced 2.47 Mt of concentrate containing approximately 600,000 t of Cu, 45 t of Au and 294 t of Ag, and generated about 250 Mt of overburden and waste rocks and over 150 Mt of tailings, which were deposited at the 397 ha Lohan tailings storage facility, 15.8 km from the mine and 980 m lower in altitude. The MCM site presents challenges for environmental rehabilitation due to the presence of large volumes of sulphidic minerals wastes, the very high rainfall and the large volume of polluted mine pit water...
November 15, 2016: Environmental Geochemistry and Health
https://www.readbyqxmd.com/read/27847183/management-effects-on-greenhouse-gas-dynamics-in-fen-ditches
#20
Mike Peacock, Luke M Ridley, Chris D Evans, Vincent Gauci
Globally, large areas of peatland have been drained through the digging of ditches, generally to increase agricultural production. By lowering the water table it is often assumed that drainage reduces landscape-scale emissions of methane (CH4) into the atmosphere to negligible levels. However, drainage ditches themselves are known to be sources of CH4 and other greenhouse gases (GHGs), but emissions data are scarce, particularly for carbon dioxide (CO2) and nitrous oxide (N2O), and show high spatial and temporal variability...
November 12, 2016: Science of the Total Environment
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