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Water balance

Colin H Brown
The posterior pituitary gland secretes oxytocin and vasopressin (the antidiuretic hormone) into the blood system. Oxytocin is required for normal delivery of the young and for delivery of milk to the young during lactation. Vasopressin increases water reabsorption in the kidney to maintain body fluid balance and causes vasoconstriction to increase blood pressure. Oxytocin and vasopressin secretion occurs from the axon terminals of magnocellular neurons whose cell bodies are principally found in the hypothalamic supraoptic nucleus and paraventricular nucleus...
September 15, 2016: Comprehensive Physiology
Tuan Anh Pham, Tadashi Ogitsu, Edmond Y Lau, Eric Schwegler
Establishing an accurate and predictive computational framework for the description of complex aqueous solutions is an ongoing challenge for density functional theory based first-principles molecular dynamics (FPMD) simulations. In this context, important advances have been made in recent years, including the development of sophisticated exchange-correlation functionals. On the other hand, simulations based on simple generalized gradient approximation (GGA) functionals remain an active field, particularly in the study of complex aqueous solutions due to a good balance between the accuracy, computational expense, and the applicability to a wide range of systems...
October 21, 2016: Journal of Chemical Physics
Saman Alavi, Ryo Ohmura
When compressed with water or ice under high pressure and low temperature conditions, some gases form solid gas hydrate inclusion compounds which have higher melting points than ice under those pressures. In this work, we study the balance of the guest-water and water-water interaction energies that lead to the formation of the clathrate hydrate phases. In particular, molecular dynamics simulations with accurate water potentials are used to study the energetics of the formation of structure I (sI) and II (sII) clathrate hydrates of methane, ethane, and propane...
October 21, 2016: Journal of Chemical Physics
Mohammad Rafat Sadat, Stefan Bringuier, Abu Asaduzzaman, Krishna Muralidharan, Lianyang Zhang
In this paper, molecular dynamics simulations are used to study the effect of molecular water and composition (Si/Al ratio) on the structure and mechanical properties of fully polymerized amorphous sodium aluminosilicate geopolymer binders. The X-ray pair distribution function for the simulated geopolymer binder phase showed good agreement with the experimentally determined structure in terms of bond lengths of the various atomic pairs. The elastic constants and ultimate tensile strength of the geopolymer binders were calculated as a function of water content and Si/Al ratio; while increasing the Si/Al ratio from one to three led to an increase in the respective values of the elastic stiffness and tensile strength, for a given Si/Al ratio, increasing the water content decreased the stiffness and strength of the binder phase...
October 7, 2016: Journal of Chemical Physics
Nikita Tretyakov, Periklis Papadopoulos, Doris Vollmer, Hans-Jürgen Butt, Burkhard Dünweg, Kostas Ch Daoulas
Classical density functional theory is applied to investigate the validity of a phenomenological force-balance description of the stability of the Cassie state of liquids on substrates with nanoscale corrugation. A bulk free-energy functional of third order in local density is combined with a square-gradient term, describing the liquid-vapor interface. The bulk free energy is parameterized to reproduce the liquid density and the compressibility of water. The square-gradient term is adjusted to model the width of the water-vapor interface...
October 7, 2016: Journal of Chemical Physics
Andreas C Bryhn, Peter H Dimberg, Lena Bergström, Ronny E Fredriksson, Johanna Mattila, Ulf Bergström
Identifying the main sources of nutrient loading is a key factor for efficient mitigation of eutrophication. This study has investigated the pathways of external nutrient loading to 656 coastal water bodies along the entire Swedish coastline. The studied water bodies have been delineated to meet requirements in the European Union's Water Framework Directive, and recent status assessments have shown that 57% of them fail to attain good or high ecological status with respect to nutrients. The analysis in the study was performed on data from mass-balance based nutrient budgets computed using the modelling framework Vattenwebb...
October 22, 2016: Marine Pollution Bulletin
Yohannes Yihdego, Len Drury
Analytical and empirical solution coupled with water balance method were used to predict the ground water inflow to a mine pit excavated below the water table, final pit lake level/recovery and radius of influence, through long-term and time variant simulations. The solution considers the effect of decreased saturated thickness near the pit walls, distributed recharge to the water table and upward flow through the pit bottom. The approach is flexible to accommodate the anisotropy/heterogeneity of the real world...
November 2016: Environmental Monitoring and Assessment
Robert D Black, Lesco L Rogers, Kristen K Ade, Heather A Nicoletto, Heather D Adkins, Daniel T Laskowitz
Caloric vestibular stimulation (CVS) to elicit the vestibulo-ocular reflex has long been used in clinical settings to aid in the diagnosis of balance disorders and to confirm the absence of brainstem function. While a number of studies have hinted at the potential therapeutic applications of CVS, the limitations of existing devices have frustrated that potential. Current CVS irrigators use water or air during short-duration applications; however, this approach is not tenable for longer duration therapeutic protocols or home use...
2016: IEEE Journal of Translational Engineering in Health and Medicine
Cathy Joanna Jensen, Frauke Demol, Romy Bauwens, Ron Kooijman, Ann Massie, Agnès Villers, Laurence Ris, Jacques De Keyser
In vitro and in vivo studies suggest that the astrocytic adrenergic signalling enhances glycogenolysis which provides energy to be transported to nearby cells and in the form of lactate. This energy source is important for motor and cognitive functioning. While it is suspected that the β2-adrenergic receptor on astrocytes might contribute to this energy balance, it has not yet been shown conclusively in vivo. Inducible astrocyte specific β2-adrenergic receptor knock-out mice were generated by crossing homozygous β2-adrenergic receptor floxed mice (Adrb2flox) and mice with heterozygous tamoxifen-inducible Cre recombinase-expression driven by the astrocyte specific L-glutamate/L-aspartate transporter promoter (GLAST-CreERT2)...
2016: PloS One
Pradeep Mugunthan, Kevin T Russell, Binglei Gong, Michael J Riley, Arthur Chin, Blair G McDonald, Linda J Eastcott
There is an identified need for fully representing groundwater-surface water transition zone (i.e., the sediment zone that connects groundwater and surface water) processes in modeling fate and transport of contaminants to assist with management of contaminated sediments. Most existing groundwater and surface water fate and transport models are not dynamically linked and do not consider transition zone processes such as bioturbation and deposition and erosion of sediments. An interface module is developed herein to holistically simulate the fate and transport by coupling two commonly used models, Environmental Fluid Dynamics Code (EFDC) and SEAWAT, to simulate surface water and groundwater hydrodynamics, while providing an enhanced representation of the processes in the transition zone...
October 24, 2016: Ground Water
Nigel Lee, Sue Kildea, Helen Stapleton
PROBLEM/BACKGROUND: Sterile water injections (SWI) are gaining popularity amongst women and midwives for the relief of back pain in labour. However the brief but intense pain associated with the injection has been cited as a deterrent to use and may negatively affect the birth experience. AIM: To explore women's experiences of using sterile water injections as analgesia for back pain in labour. DESIGN: A qualitative study, which generated data through individual semi-structured interviews with postnatal women...
October 19, 2016: Women and Birth: Journal of the Australian College of Midwives
Rungaroon Pimparu, Sira Nitiyanontakit, Manuel Miró, Pakorn Varanusupakul
The concept of dynamic single-interface hollow fiber membrane liquid-phase microextraction (HF-LPME), where the target analyte was extracted on-line and eluted inside the lumen of the HF membrane, was explored. An ionic liquid containing supported liquid membrane was used for the trace determination of Cr(VI) as a model compound. Since the extraction took place on-line inside the hollow fiber membrane, the mass transfer behavior was described and discussed in comparison with the conventional HF-LPME. The extraction efficiency was improved by a recirculation configuration of the sample solution at relatively high sampling flow rates as a result of the increased effective contact area...
December 1, 2016: Talanta
Fengjiao Chen, Qishan Zhu, Yeyun Wang, Wei Cui, Xiaodong Su, Yanguang Li
Increasing attention has now been focused on the photoelectrochemical (PEC) hydrogen evolution as a promising route to transform solar energy into chemical fuels. Silicon is one of the most studied PEC electrode materials, but its performance is still limited by its inherent PEC instability and electrochemical inertness toward water splitting. To achieve significant PEC activities, silicon-based photoelectrodes usually have to be coupled with proper cocatalysts, and thus formed semiconductor/cocatalyst interface represents a critical structural parameter in the rational design of efficient PEC devices...
October 21, 2016: ACS Applied Materials & Interfaces
Jie Liu, Liang Guo, Jiping Jiang, Dexun Jiang, Peng Wang
In the emergency management relevant to chemical contingency spills, efficiency emergency rescue can be deeply influenced by a reasonable assignment of the available emergency materials to the related risk sources. In this study, an emergency material scheduling model (EMSM) with time-effective and cost-effective objectives is developed to coordinate both allocation and scheduling of the emergency materials. Meanwhile, an improved genetic algorithm (IGA) which includes a revision operation for EMSM is proposed to identify the emergency material scheduling schemes...
October 20, 2016: Environmental Science and Pollution Research International
Fabiana de Salvi Guimarães, Wilson Max Almeida Monteiro de Moraes, Luis Henrique Marchesi Bozi, Pâmela R Souza, Ednei Luiz Antonio, Danilo Sales Bocalini, Paulo José Ferreira Tucci, Daniel Araki Ribeiro, Patricia Chakur Brum, Alessandra Medeiros
Dexamethasone is a potent and widely used anti-inflammatory and immunosuppressive drug. However, recent evidences suggest that dexamethasone cause pathologic cardiac remodeling, which later impairs cardiac function. The mechanism behind the cardiotoxic effect of dexamethasone is elusive. The present study aimed to verify if dexamethasone-induced cardiotoxicity would be associated with changes in the cardiac net balance of calcium handling protein and calcineurin signaling pathway activation. Wistar rats (~400 g) were treated with dexamethasone (35 µg/g) in drinking water for 15 days...
October 19, 2016: Molecular and Cellular Biochemistry
Azam Moshtaghi, Md Lifat Rahi, Viet Tuan Nguyen, Peter B Mather, David A Hurwood
BACKGROUND: Understanding the genomic basis of osmoregulation (candidate genes and/or molecular mechanisms controlling the phenotype) addresses one of the fundamental questions in evolutionary ecology. Species distributions and adaptive radiations are thought to be controlled by environmental salinity levels, and efficient osmoregulatory (ionic balance) ability is the main mechanism to overcome the problems related to environmental salinity gradients. METHODS: To better understand how osmoregulatory performance in freshwater (FW) crustaceans allow individuals to acclimate and adapt to raised salinity conditions, here we (i), reviewed the literature on genes that have been identified to be associated with osmoregulation in FW crustaceans, and (ii), performed a transcriptomic analysis using cDNA libraries developed from mRNA isolated from three important osmoregulatory tissues (gill, antennal gland, hepatopancreas) and total mRNA from post larvae taken from the freshwater prawn, Macrobrachium australiense using Illumina deep sequencing technology...
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
Vicente de Paulo R da Silva, Sonaly D de Oliveira, Célia C Braga, José Ivaldo B Brito, Francisco de Assis S de Sousa, Romildo M de Holanda, João Hugo B C Campos, Enio P de Souza, Armando César R Braga, Rafaela S Rodrigues Almeida, Lincoln E de Araújo
Virtual water trade is often considered a solution for restricted water availability in many regions of the world. Brazil is the world leader in the production and export of various agricultural and livestock products. The country is either a strong net importer or a strong net exporter of these products. The objective of this study is to determine the volume of virtual water contained in agricultural and livestock products imported/exported by Brazil from 1997 to 2012, and to define the water self-sufficiency index of agricultural and livestock products in Brazil...
October 16, 2016: Journal of Environmental Management
Nir Kampf, Chunxian Wu, Yilin Wang, Jacob Klein
The surface structure of the trimeric surfactant tri(dodecyldimethylammonioacetoxy)-diethyltriamine trichloride (DTAD) on mica, and the interactions between two such DTAD-coated surfaces were determined using atomic force microscopy and a surface force balance. In an aqueous solution of 3 mM, five times the critical aggregation concentration (CAC), the surfaces are coated with worm-like micelles or hemi-micelles and larger (ca. 80 nm) bilayer vesicles. Repulsive normal interactions between the surfaces indicate a net surface charge and a solution concentration of ions close to that expected from the CAC...
October 19, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Justin A Lemkul, Alexander D MacKerell
Mg2+ ions are important in biological systems, particularly in stabilizing compact RNA folds. Mg2+ is strongly polarizing, and representing its interactions in heterogeneous environments is a challenge for empirical force field development. To date, the most commonly used force fields in molecular dynamics simulations utilize a pairwise-additive approximation for electrostatic interactions, which cannot account for the significant polarization response in systems containing Mg2+. In the present work, we refine the interactions of Mg2+ with water, Cl- ions, and nucleic acid moieties using a polarizable force field based on the classical Drude oscillator model...
October 19, 2016: Journal of Physical Chemistry. B
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