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Water transport

Yong-Jun Ye, Xin-Tao Dai, De-Xin Ding, Ya-Li Zhao
In this study, a one-dimensional steady-state mathematical model of radon transport in fragmented uranium ore was established according to Fick's law and radon transfer theory in an air-water interface. The model was utilized to obtain an analytical solution for radon concentration in the air-water, two-phase system under steady state conditions, as well as a corresponding radon exhalation rate calculation formula. We also designed a one-dimensional experimental apparatus for simulating radon diffusion migration in the uranium ore with various water levels to verify the mathematical model...
October 19, 2016: Journal of Environmental Radioactivity
Alexandra Asaro, Gregory Ziegler, Cathrine Ziyomo, Owen Hoekenga, Brian Dilkes, Ivan Baxter
Plants obtain soil-resident elements that support growth and metabolism from the water- flow facilitated by transpiration and active transport processes. The availability of elements in the environment interacts with the genetic capacity of organisms to modulate element uptake through plastic adaptive responses, such as homeostasis. These interactions should cause the elemental contents of plants to vary such that the effects of genetic polymorphisms will be dramatically dependent on the environment in which the plant is grown...
October 21, 2016: G3: Genes—Genomes—Genetics
Angkana Sommanustweechai, Weerasak Putthasri, Mya Lay Nwe, Saw Thetlya Aung, Mya Min Theint, Viroj Tangcharoensathien, San Shway Wynn
BACKGROUND: Myanmar is classified as critical shortage of health workforce. In responses to limited number of trained health workforce in the hard-to-reach and remote areas, the MOH trained the Community Health Worker (CHW) as health volunteers serving these communities on a pro bono basis. This study aimed to assess the socio-economic profiles, contributions of CHW to primary health care services and their needs for supports to maintain their quality contributions in rural hard to reach areas in Myanmar...
October 21, 2016: Human Resources for Health
Wei Huang, Ying-Jie Yang, Hong Hu, Shi-Bao Zhang
Low temperature associated with high light can induce photoinhibition of photosystem I (PSI) and photosystem II (PSII). However, the photosynthetic electron flow and specific photoprotective responses in alpine evergreen broad-leaf plants in winter is unclear. We analyzed seasonal changes in PSI and PSII activities, and energy quenching in PSI and PSII in three alpine broad-leaf tree species, Quercus guyavifolia (Fagaceae), Rhododendron decorum (Ericaceae), Euonymus tingens (Celastraceae). In winter, PSII activity remained stable in Q...
October 13, 2016: Journal of Photochemistry and Photobiology. B, Biology
Vi Khanh Truong, Miljan Stefanovic, Shane Maclaughlin, Mark Tobin, Jitraporn Vongsvivut, Mohammad Al Kobaisi, Russell J Crawford, Elena P Ivanova
Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, building and food industries, amongst others. Polyester and coatings containing both polyester and silica nanoparticles (SiO2NPs) have been widely used to protect steel substrata from corrosion. In this study, we utilized X-ray photoelectron spectroscopy, attenuated total reflection infrared micro-spectroscopy, water contact angle measurements, optical profiling and atomic force microscopy to provide an insight into how exposure to sunlight can cause changes in the micro- and nanoscale integrity of the coatings...
October 11, 2016: Journal of Visualized Experiments: JoVE
Vernon G Thomas, Robert H Hanner, Alex V Borisenko
Managing invasive alien species in Canada requires reliable taxonomic identification as the basis of rapid-response management. This can be challenging, especially when organisms are small and lack morphological diagnostic features. DNA-based techniques, such as DNA barcoding, offer a reliable, rapid, and inexpensive toolkit for taxonomic identification of individual or bulk samples, forensic remains, and even environmental DNA. Well suited for this requirement, they could be more broadly deployed and incorporated into the operating policy and practices of Canadian federal departments and should be authorized under these agencies' articles of law...
July 19, 2016: Genome Génome / Conseil National de Recherches Canada
Mangesh I Chaudhari, Jijeesh R Nair, Lawrence R Pratt, Fernando A Soto, Perla B Balbuena, Susan Rempe
Lithium ion solvation and diffusion properties in ethylene carbonate (EC) and propylene carbonate (PC) are studied by molecular simulation, experiments, and electronic structure calculations. Studies carried out in water provide a reference for interpretation. Classical molecular dynamics simulation results are compared to ab initio molecular dynamics to as- sess non-polarizable force field parameters for solvation structure of the carbonate solvents. Quasi-chemical theory (QCT) is adapted to take advantage of four-fold occupancy of the near-neighbor solvation structure observed in simulations, and used to calculate solvation free energies...
October 21, 2016: Journal of Chemical Theory and Computation
Thomas Pannicke, T Ivo Chao, Miriam Reisenhofer, Mike Francke, Andreas Reichenbach
Müller cells are the dominant macroglial cells in the retina of all vertebrates. They fulfill a variety of functions important for retinal physiology, among them spatial buffering of K(+) ions and uptake of glutamate and other neurotransmitters. To this end, Müller cells express inwardly rectifying K(+) channels and electrogenic glutamate transporters. Moreover, a lot of voltage- and ligand-gated ion channels, aquaporin water channels, and electrogenic transporters are expressed in Müller cells, some of them in a species-specific manner...
October 21, 2016: Glia
Débora Claësson, Tobias Wang, Hans Malte
Global warming results in increasing water temperature, which may represent a threat to aquatic ectotherms. The rising temperature affects ecology through physiology, by exerting a direct limiting effect on the individual. The mechanism controlling individual thermal tolerance is still elusive, but some evidence shows that the heart plays a central role, and that insufficient transport of oxygen to the respiring tissues may determine the thermal tolerance of animals. In this study, the influence of the heart in thermal limitation was investigated by measurements of aerobic scope in the European eel (Anguilla anguilla) together with measurements of cardiac output during rest and activity...
2016: Conservation Physiology
F Selge, E Matta, R Hinkelmann, G Gunkel
Large flow-through reservoirs and lakes possess environmental gradients and monitoring programs are mostly adapted for cost and time effectiveness. Bay areas are often more isolated from the main water body and are likely to have unobserved different environmental processes and impacts. This study was performed at the Itaparica Reservoir, São Francisco River, located in semi-arid Northeast Brazil, with dendritic form. Water residence time in the Icó-Mandantes Bay was estimated by hydrodynamic flow and transport simulations...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Andrés Núñez, Guillermo Amo de Paz, Alberto Rastrojo, Ana M García, Antonio Alcamí, A Montserrat Gutiérrez-Bustillo, Diego A Moreno
The first part of this review ("Monitoring of airborne biological particles in outdoor atmosphere. Part 1: Importance, variability and ratios") describes the current knowledge on the major biological particles present in the air regarding their global distribution, concentrations, ratios and influence of meteorological factors in an attempt to provide a framework for monitoring their biodiversity and variability in such a singular environment as the atmosphere. Viruses, bacteria, fungi, pollen and fragments thereof are the most abundant microscopic biological particles in the air outdoors...
March 2016: International Microbiology: the Official Journal of the Spanish Society for Microbiology
Ana C Henriques, Rui M S Azevedo, Paolo De Marco
Methanesulfonic acid (MSA) is a relevant intermediate of the biogeochemical cycle of sulfur and environmental microorganisms assume an important role in the mineralization of this compound. Several methylotrophic bacterial strains able to grow on MSA have been isolated from soil or marine water and two conserved operons, msmABCD coding for MSA monooxygenase and msmEFGH coding for a transport system, have been repeatedly encountered in most of these strains. Homologous sequences have also been amplified directly from the environment or observed in marine metagenomic data, but these showed a base composition (G + C content) very different from their counterparts from cultivated bacteria...
2016: PeerJ
Hyun Jun Jung, Tae-Hwan Kwon
Kidney collecting duct is an important renal tubular segment for regulation of body water homeostasis and urine concentration. Water reabsorption in the collecting duct principal cells is controlled by vasopressin, a peptide hormone which induces the osmotic water transport across the collecting duct epithelia through regulation of water channel proteins aquaporin-2 (AQP2) and aquaporin-3 (AQP3). In particular, vasopressin induces both intracellular translocation of AQP2-bearing vesicles to the apical plasma membrane and transcription of Aqp2 gene to increase AQP2 protein abundance...
October 19, 2016: American Journal of Physiology. Renal Physiology
Baofu Qiao, Ross Elli, Geoffroy Ferru
We address the structures and energetics of ion solvation in aqueous and organic solutions to understand liquid-liquid ion transport. Atomistic molecular dynamics (MD) simulations with polarizable force field are performed to study the coordination transformations driving lanthanide (Ln(III)) and nitrate ion transport between aqueous and an alkylamide-oil solution. An enhancement of the coordination behavior in the organic phase is achieved in contrast with the aqueous solution. In particular, the coordination number of Ce3+ increases from 8...
October 19, 2016: Chemistry: a European Journal
Ding Pan, Giulia Galli
Investigating the fate of dissolved carbon dioxide under extreme conditions is critical to understanding the deep carbon cycle in Earth, a process that ultimately influences global climate change. We used first-principles molecular dynamics simulations to study carbonates and carbon dioxide dissolved in water at pressures (P) and temperatures (T) approximating the conditions of Earth's upper mantle. Contrary to popular geochemical models assuming that molecular CO2(aq) is the major carbon species present in water under deep Earth conditions, we found that at 11 GPa and 1000 K, carbon exists almost entirely in the forms of solvated carbonate ([Formula: see text]) and bicarbonate ([Formula: see text]) ions and that even carbonic acid [H2CO3(aq)] is more abundant than CO2(aq)...
October 2016: Science Advances
Yang Ruan, Yudan Zhu, Yumeng Zhang, Qingwei Gao, Xiaohua Lu, Linghong Lu
Residual Mg2+ could reduce the performance of lithium-ion batteries, but separating Mg2+ and Li+ is difficult because of their similar ionic properties. Inspired by the high selectivity of biological Mg2+ channels, this work investigates the ability of graphene-based nanopores with different diameters (0.789, 1.024 and 1.501 nm) to separate Mg2+ and Li+ under a series of transmembrane voltages using atomistic simulations. We analyzed the spatial distribution of molecules in the pore vicinity, ionic hydration structure properties, and potential of mean force of ions traveling through the nanopores...
October 18, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Wieland Fricke
Water transport in plants occurs along various paths and is driven by gradients in its free energy. It is generally considered that the mode of transport, being either diffusion or bulk flow, is a passive process, though energy may be required to sustain the forces driving water flow. This review aims at putting water flow at the various organisational levels (cell, organ, plant) in the context of the energy that is required to maintain these flows. In addition, the question is addressed (i) whether water can be transported against a difference in its chemical free energy, 'water potential' (Ψ), through, directly or indirectly, active processes; and (ii) whether the energy released when water is flowing down a gradient in its energy, for example during day-time transpiration and cell expansive growth, is significant compared to the energy budget of plant and cell...
October 18, 2016: Plant, Cell & Environment
Chenyi Cai, Min Kuang, Xiling Chen, Hao Wu, Hongtao Ge, Gengfeng Zheng
The development of efficient and robust electrocatalyst has been the central of the solar water splitting-based hydrogen fuel acquisition. In this work, we reported the use of cow milk, with addition of tetraethyl orthosilicate (TEOS) and melamine, for the synthesis of nitrogen-doped mesoporous carbon microspheres. Due to the large surface and enhanced charge transport behavior, the obtained samples enabled low overpotentials and a small Tafel slope toward oxygen evolution reaction, which were close or comparable to the best OER catalysts of carbon materials reported previously...
October 12, 2016: Journal of Colloid and Interface Science
Ramsa Chaves-Ulloa, Brad W Taylor, Hannah J Broadley, Kathryn L Cottingham, Nicholas A Baer, Kathleen C Weathers, Holly A Ewing, Celia Y Chen
Mercury (Hg) concentrations in aquatic environments have increased globally, exposing consumers of aquatic organisms to high Hg levels. For both aquatic and terrestrial consumers, exposure to Hg depends on their food sources as well as environmental factors influencing Hg bioavailability. The majority of the research on the transfer of methylmercury (MeHg), a toxic and bioaccumulating form of Hg, between aquatic and terrestrial food webs has focused on terrestrial piscivores. However, a gap exists in our understanding of the factors regulating MeHg bioaccumulation by non-piscivorous terrestrial predators, specifically consumers of adult aquatic insects...
September 2016: Ecological Applications: a Publication of the Ecological Society of America
Andreas Reichenbach, Andreas Bringmann
Müller glia, the principal macroglia of the retina, express diverse subtypes of adenosine and metabotropic purinergic (P2Y) receptors. Müller cells of several species, including man, also express ionotropic P2X7 receptors. ATP is liberated from Müller cells after activation of metabotropic glutamate receptors and during osmotic and mechanical induction of membrane stretch; adenosine is released through equilibrative nucleoside transporters. Müller cell-derived purines modulate the neuronal activity and have autocrine effects, for example, induction of glial calcium waves and regulation of the cellular volume...
October 2016: Journal of Ocular Pharmacology and Therapeutics
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