Regioselective Synthesis of Cellulose Ester Homopolymers

Science.gov (United States)

Daiqiang Xu; Kristen Voiges; Thomas Elder; Petra Mischnick; Kevin J. Edgar

2012-01-01

Regioselective synthesis of cellulose esters is extremely difficult due to the small reactivity differences between cellulose hydroxyl groups, small differences in steric demand between acyl moieties of interest, and the difficulty of attaching and detaching many protecting groups in the presence of cellulose ester moieties without removing the ester groups. Yet the...

Lewis acid controlled regioselectivity in styrene hydrocyanation

NARCIS (Netherlands)

Bini, L.; Pidko, E.A.; Müller, C.; Santen, van R.A.; Vogt, D.

2009-01-01

According to present knowledge, the Ni-catalyzed hydrocyanation of styrene leads predominantly to the branched product 2-phenylpropionitrile (98%). We observed a dramatic inversion of the regioselectivity upon addition of a Lewis acid. Up to 83 % of the linear product 3-phenylpropionitrile was

Regioselective Benzoylation of Diols and Carbohydrates by Catalytic Amounts of Organobase.

Science.gov (United States)

Lu, Yuchao; Hou, Chenxi; Ren, Jingli; Xin, Xiaoting; Xu, Hengfu; Pei, Yuxin; Dong, Hai; Pei, Zhichao

2016-05-17

A novel metal-free organobase-catalyzed regioselective benzoylation of diols and carbohydrates has been developed. Treatment of diol and carbohydrate substrates with 1.1 equiv. of 1-benzoylimidazole and 0.2 equiv. of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in MeCN under mild conditions resulted in highly regioselective benzoylation for the primary hydroxyl group. Importantly, compared to most commonly used protecting bulky groups for primary hydroxyl groups, the benzoyl protective group offers a new protection strategy.

Regioselective alkane hydroxylation with a mutant CYP153A6 enzyme

Science.gov (United States)

Koch, Daniel J.; Arnold, Frances H.

2013-01-29

Cytochrome P450 CYP153A6 from Myobacterium sp. strain HXN1500 was engineered using in-vivo directed evolution to hydroxylate small-chain alkanes regioselectively. Mutant CYP153A6-BMO1 selectively hydroxylates butane and pentane at the terminal carbon to form 1-butanol and 1-pentanol, respectively, at rates greater than wild-type CYP153A6 enzymes. This biocatalyst is highly active for small-chain alkane substrates and the regioselectivity is retained in whole-cell biotransformations.

Molecular Weight and Structural Properties of Biodegradable PLA Synthesized with Different Catalysts by Direct Melt Polycondensation

Directory of Open Access Journals (Sweden)

Hyung Woo Lee

2015-09-01

Full Text Available Production of biodegradable polylactic acid (PLA from biomassbased lactic acid is widely studied for substituting petro-based plastics or polymers. This study investigated PLA production from commercial lactic acid in a batch reactor by applying a direct melt polycondensation method with two kinds of catalyst, γ-aluminium(III oxide (γ-Al2O3 or zinc oxide (ZnO, in reduced pressure. The molecular weight of the synthesized PLA was determined by capillary viscometry and its structural properties were analyzed by functional group analysis using FT-IR. The yields of polymer production with respect to the theoretical conversion were 47% for γ-Al2O3 and 35% for ZnO. However, the PLA from ZnO had a higher molecular weight (150,600 g/mol than that from γ-Al2O3 (81,400 g/mol. The IR spectra of the synthesized PLA from both catalysts using polycondensation show the same behavior of absorption peaks at wave numbers from 4,500 cm-1 to 500 cm-1, whereas the PLA produced by two other polymerization methods – polycondensation and ring opening polymerization –showed a significant difference in % transmittance intensity pattern as well as peak area absorption at a wave number of 3,500 cm-1 as –OH vibration peak and at 1,750 cm-1 as –C=O carbonyl vibrational peak.

Use of co2 for the synthesis of cyclic glycocarbonates and linear polyglycocarbonates by polycondensation from glycans

KAUST Repository

Gnanou, Yves

2016-10-20

Provided herein are methods for synthesizing cyclic carbonates, glycocarbonates, and polyglycocarbonates by reacting polyol glycans with carbon dioxide. Synthesis can include selective polycondensation of polyol glycan hydroxyl moieties.

Use of co2 for the synthesis of cyclic glycocarbonates and linear polyglycocarbonates by polycondensation from glycans

KAUST Repository

Gnanou, Yves; Pati, Debasis; Feng, Xiaoshuang; Hadjichristidis, Nikolaos

2016-01-01

Provided herein are methods for synthesizing cyclic carbonates, glycocarbonates, and polyglycocarbonates by reacting polyol glycans with carbon dioxide. Synthesis can include selective polycondensation of polyol glycan hydroxyl moieties.

Photoresponsive Azopolyester–PMMA Block Copolymers Obtained by Combination of ATRP, Polycondensation, and “Click” Chemistry

DEFF Research Database (Denmark)

Berges, Cristina; Javakhishvili, Irakli; Hvilsted, Søren

2012-01-01

Novel azobenzene‐containing block copolymers (BCs) with a polyester block bearing azobenzene moieties in the side chain and a poly (methyl methacrylate) (PMMA) block have been synthesized by the combination of atom transfer radical polymerization (ATRP), polycondensation, and “click” chemistry. Two...

Regioselectivity and Enantioselectivity in Nickel-Catalysed Reductive Coupling Reactions of Alkynes

Science.gov (United States)

Moslin, Ryan M.; Miller-Moslin, Karen; Jamison, Timothy F.

2011-01-01

Nickel-catalysed reductive coupling reactions of alkynes have emerged as powerful synthetic tools for the selective preparation of functionalized alkenes. One of the greatest challenges associated with these transformations is control of regioselectivity. Recent work from our laboratory has provided an improved understanding of several of the factors governing regioselectivity in these reactions, and related studies have revealed that the reaction mechanism can differ substantially depending on the ligand employed. A discussion of stereoselective transformations and novel applications of nickel catalysis in coupling reactions of alkynes is also included. PMID:17971951

Rhodium-Catalyzed Regioselective C7-Olefination of Indazoles Using an N-Amide Directing Group.

Science.gov (United States)

Guo, Lei; Chen, Yanyu; Zhang, Rong; Peng, Qiujun; Xu, Lanting; Pan, Xianhua

2017-02-01

A rhodium-catalyzed regioselective C-H olefination of indazole is described. This protocol relies on the use of an efficient and removable N,N-diisopropylcarbamoyl directing group, which offers facile access to C7-olefinated indazoles with high regioselectivity, ample substrate scope and broad functional group tolerance. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Breaking the regioselectivity rule for acrylate insertion in the Mizoroki-Heck reaction.

Science.gov (United States)

Wucher, Philipp; Caporaso, Lucia; Roesle, Philipp; Ragone, Francesco; Cavallo, Luigi; Mecking, Stefan; Göttker-Schnetmann, Inigo

2011-05-31

In modern methods for the preparation of small molecules and polymers, the insertion of substrate carbon-carbon double bonds into metal-carbon bonds is a fundamental step of paramount importance. This issue is illustrated by Mizoroki-Heck coupling as the most prominent example in organic synthesis and also by catalytic insertion polymerization. For unsymmetric substrates H(2)C = CHX the regioselectivity of insertion is decisive for the nature of the product formed. Electron-deficient olefins insert selectively in a 2,1-fashion for electronic reasons. A means for controlling this regioselectivity is lacking to date. In a combined experimental and theoretical study, we now report that, by destabilizing the transition state of 2,1-insertion via steric interactions, the regioselectivity of methyl acrylate insertion into palladium-methyl and phenyl bonds can be inverted entirely to yield the opposite "regioirregular" products in stoichiometric reactions. Insights from these experiments will aid the rational design of complexes which enable a catalytic and regioirregular Mizoroki-Heck reaction of electron-deficient olefins.

Dehydration

Science.gov (United States)

... chronic illness have a greater risk. Signs of dehydration in adults include Being thirsty Urinating less often ... skin Feeling tired Dizziness and fainting Signs of dehydration in babies and young children include a dry ...

Electronic and steric effects in regioselective tritiation of anilides

Energy Technology Data Exchange (ETDEWEB)

OOhashi, Kunio; Udo, Masato (Chiba Univ. (Japan). Coll. of Arts and Sciences)

1992-07-01

Acetanilide, propionanilide and isobutyranilide were tritiated at the ortho positions with very high regioselectivity by heating with HTO in the presence of RhCl[sub 3][center dot]3H[sub 2]O in N, N-dimethylformamide (DMF). In this reaction for pivalanilide the specific activity alone was determined, because attempts to establish the regioselectivity were unsuccessful. The extent of tritium incorporation decreased with increasing bulkiness of the alkyl groups. Only slight tritium was introduced by the same reaction for trifluoroacetanilide, which would probably be attributed to a strong electron-attracting property of the trifluoromethyl group. The above findings give support to the previous suggestion that the present isotope exchange reaction proceeds via an initial coordination of the nitrogen atom of anilides to the rhodium (III) chloride trihydrate catalyst. (author).

MULTICOMPONENT AND REGIOSELECTIVE SYNTHESIS OF DIHYDROPYRAZOLO[1,5-a]PYRIMIDINES FROM AROMATIC ALDEHYDES, MELDRUM'S ACID AND AMINOPYRAZOLE CAN508

OpenAIRE

Jedinák, L.; Kryštof, V. (Vladimír); Trávníček, Z.; Cankař, P.

2014-01-01

A regioselective synthesis of dihydropyrazolo[1,5-a]pyrimidines is reported. The multicomponent reaction of readily available arylaldehydes, Meldrum's acid, and aminopyrazole CAN508 afforded fused pyrazolopyrimidines in high yields. The reaction proceeded regioselectively via initial Michael addition of the exocyclic amino group to arylidene Meldrum's acid intermediate followed by a ring closure at the endocyclic nitrogen of aminopyrazole. The regioselectivity of the reaction was determined b...

Regioselective iodoazidation of alkynes: synthesis of α,α-diazidoketones.

Science.gov (United States)

Okamoto, Noriko; Sueda, Takuya; Minami, Hideki; Miwa, Yoshihisa; Yanada, Reiko

2015-03-06

Aryl alkyl alkynes reacted with N-iodosuccinimide (NIS) and trimethylsilyl azide (TMSN3), leading to α,α-diazidoketones via the regioselective addition of IN3 to alkynes. Huisgen cyclization of α,α-diazidoketones generated bis-triazole compounds.

Factors influencing the regioselectivity of the oxidation of asymmetric secondary amines with singlet oxygen.

Science.gov (United States)

Ushakov, Dmitry B; Plutschack, Matthew B; Gilmore, Kerry; Seeberger, Peter H

2015-04-20

Aerobic amine oxidation is an attractive and elegant process for the α functionalization of amines. However, there are still several mechanistic uncertainties, particularly the factors governing the regioselectivity of the oxidation of asymmetric secondary amines and the oxidation rates of mixed primary amines. Herein, it is reported that singlet-oxygen-mediated oxidation of 1° and 2° amines is sensitive to the strength of the α-C-H bond and steric factors. Estimation of the relative bond dissociation energy by natural bond order analysis or by means of one-bond C-H coupling constants allowed the regioselectivity of secondary amine oxidations to be explained and predicted. In addition, the findings were utilized to synthesize highly regioselective substrates and perform selective amine cross-couplings to produce imines. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method Development in the Regioselective Glycosylation of Unprotected Carbohydrates

DEFF Research Database (Denmark)

Niedbal, Dominika Alina

and the glycosylations were promoted by tetrabutylammonium bromide. The couplings were completely selective and gave rise to a number of 1,6-linked disaccharides with 1,2- cis-linked orientation. Project 2: Boron-mediated glycosylation of unprotected carbohydrates Boron-mediated regioselective Koenigs...

Mechanism and regioselectivity of 1,3-dipolar cycloaddition ...

Indian Academy of Sciences (India)

1,3-Dipolar cycloaddition; sulphur-centred 1,3-dipoles; regioselectivity; DFT reactivity indices;. FMO theory. 1. Introduction. Five-membered heterocyclic compounds can be gene- rated by addition of a 1,3-dipole to a dipolarophile under a 1,3-dipolar cycloaddition (1,3-DC) reaction which is well known as pericyclic reaction.

Regularities of synthesis and mechanism of polycondensation of aromatic amines

International Nuclear Information System (INIS)

Matnishyan, Hagob

2002-01-01

Full text.Aniline polymers and its derivatives are widely used in modern electronics, electrical engineering and manufacturing of various appliances. They are used for production of electrical power sources, probes and sensors, composite materials absorbing high frequency radiations, anticorrosion coatings, nonlinear optical devices-such as lasers, cathode ray tubes, photodiodes etc. Such a wide usage of aromatic amine polymers brings up new demands to their structure and properties, which is dependent on conditions of synthesis and forming of the hard phase. The presented article describes regularities and mechanisms of oxidative polycondensation of aromatic amines. Several types of polymers have been synthesized by chemical and electrochemical oxidation of aniline and its chlor-, brom-, iodo-, nitro-, p-substituted derivatives; diphenylamine, benzidine and phenylenediamines in nonwater media. On the basis of kinetic and electrochemical studies and literature analysis we suggested a mechanism of polycondensation of aromatic amines. According to it, oxidation of amines starts with the electron transfer with cation-radical formation on the first stage, which stabilizes in acid environments due to complex formation with initial amine. Dimer formation and further growth of chain takes place upon another electron transfer from formed complex, which results in forming of macromolecules. We also suggested a scheme for obtaining of structures defect in media assisting in deprotonizing of cation radicals and formation of arylamine radical centers. Those processes lead to formation of azo- and diphenyl fragments in the main chain of the polymer and predetermine the possibility of chain disruption. We also considered reactions leading to formation of branched polymers and cyclic structures, such as phenazine in particular. The peculiarity of electrochemical process lies in regulation of concentration of active centres on the positive electrode surface

Dehydration (For Parents)

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Dehydration KidsHealth / For Parents / Dehydration What's in this article? ... Be Prevented? Print en español Deshidratación What Is Dehydration? We all lose some body water every day ...

Effect of leaf dehydration duration and dehydration degree on PSII photochemical activity of papaya leaves.

Science.gov (United States)

Liu, Meijun; Zhang, Zishan; Gao, Huiyuan; Yang, Cheng; Fan, Xingli; Cheng, Dandan

2014-09-01

Although the effect of dehydration on photosynthetic apparatus has been widely studied, the respective effect of dehydration duration and dehydration degree was neglected. This study showed that, when leaves dehydrated in air, the PSII activities of leaves decreased with the decline of leaf relative water content (RWC). Unexpectedly, when leaves dehydrated to same RWC, the decreases in Fv/Fm, Ψo and RC/CSm were lower in leaves dehydrating at 43 °C than those at 25 °C. However, to reach the same RWC, leaves dehydrating at 43 °C experienced 1/6 of the dehydration duration for leaves dehydrating at 25 °C. To distinguish the respective effect of dehydration degree and dehydration duration on photosynthetic apparatus, we studied the PSII activities of leaves treated with different concentration of PEG solutions. Increasing dehydration degree aggravated the decline of Fv/Fm, Ψo and RC/CSm in leaves with the same dehydration duration, while prolonging the dehydration duration also exacerbated the decline of Fv/Fm, Ψo and RC/CSm in leaves with identical dehydration degree. With the same dehydration degree and duration, high temperature enhanced the decrease of Fv/Fm, Ψo and RC/CSm in the leaves. When leaves dehydrated in air, the effect of high temperature was underestimated due to reduction of dehydration duration. The results demonstrated that, dehydration degree and duration both play important roles in damage to photosynthetic apparatus. We suggest that, under combined stresses, the effects of dehydration degree and duration on plants should be considered comprehensively, otherwise, partial or incorrect results may be obtained. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

High regioselective acetylation of vitamin A precursors using lipase ...

African Journals Online (AJOL)

Administrator

2011-09-26

Sep 26, 2011 ... High regioselective acetylation of vitamin A precursors using lipase B from Candida antarctica in organic media. Jingpeng Sun, Keju Jing* and Yinghua Lu. Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen. University, Xiamen 361005, P. R. ...

Highly regioselective synthesis of undecylenic acid esters of purine nucleosides catalyzed by Candida antarctica lipase B.

Science.gov (United States)

Gao, Wen-Li; Li, Ning; Zong, Min-Hua

2011-11-01

Regioselective undecylenoylation of purine nucleosides as potential dual prodrugs was achieved by Candida antarctica lipase B using adenosine as a model reactant. The optimum organic solvent, molar ratio of vinyl ester to nucleoside, enzyme dosage, reaction temperature and molecular sieve amount were anhydrous THF, 5:1, 20 U/ml, 45°C and 75 mg/ml, respectively. Under the optimum conditions, the initial reaction rate, yield and 5'-regioselectivity were 1.1 mM/h, 90% and >99%, respectively. The enzymatic acylation of various nucleosides furnished the desired 5'-ester derivatives with the yields of 60-95% and 5'-regioselectivities of >99%. In addition, the lipase displayed excellent operational stability in THF, and retained 96% of its initial activity after reused for five batches.

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

Science.gov (United States)

Shrives, Harry J.; Fernández-Salas, José A.; Hedtke, Christin; Pulis, Alexander P.; Procter, David J.

2017-03-01

Benzothiophenes are heterocyclic constituents of important molecules relevant to society, including those with the potential to meet modern medical challenges. The construction of molecules would be vastly more efficient if carbon-hydrogen bonds, found in all organic molecules, can be directly converted into carbon-carbon bonds. In the case of elaborating benzothiophenes, functionalization of carbon-hydrogen bonds at carbon-number 3 (C3) is markedly more demanding than at C2 due to issues of regioselectivity (C3 versus C2), and the requirement of high temperatures, precious metals and the installation of superfluous directing groups. Herein, we demonstrate that synthetically unexplored but readily accessible benzothiophene S-oxides serve as novel precursors for C3-functionalized benzothiophenes. Employing an interrupted Pummerer reaction to capture and then deliver phenol and silane coupling partners, we have discovered a directing group-free method that delivers C3-arylated and -alkylated benzothiophenes with complete regioselectivity, under metal-free and mild conditions.

Regioselective alkali metal reduction of dibenzocyclooctadiene lignan derivatives, demethoxylation followed by dehalogenation.

Science.gov (United States)

Wang, Qing-Yao; Fang, Jia-Qi; Deng, Lu-Lu; Hao, Xiao-Jiang; Mu, Shu-Zhen

2017-12-27

The regioselective demethoxylation and dehalogenation of dihalogenated dibenzocyclooctadiene lignans derivatives were realized in a one-step reaction with excellent yields in the sodium and t-butanol reaction system.

Improved synthesis with high yield and increased molecular weight of poly(alpha,beta-malic acid) by direct polycondensation.

Science.gov (United States)

Kajiyama, Tetsuto; Kobayashi, Hisatoshi; Taguchi, Tetsushi; Kataoka, Kazunori; Tanaka, Junzo

2004-01-01

The development of synthetic biodegradable polymers, such as poly(alpha-hydroxy acid), is particularly important for constructing medical devices, including scaffolds and sutures, and has attracted growing interest in the biomedical field. Here, we report a novel approach to preparing high molecular weight poly(malic acid) (HMW--PMA) as a biodegradable and bioabsorbable water-soluble polymer. We investigated in detail the reaction conditions for the simple direct polycondensation of l-malic acid, including the reaction times, temperatures, and catalysts. The molecular weight of synthesized alpha,beta-PMA is dependent on both the reaction temperature and time. The optimum reaction condition to obtain alpha,beta-PMA by direct polycondensation using tin(II) chloride as a catalyst was thus determined to be 110 degrees C for 45 h with a molecular weight of 5300. The method for alpha,beta-PMA synthesis established here will facilitate production of alpha,beta-PMA of various molecular weights, which may have a potential utility as biomaterials.

1,5-Anhydro-D-fructose: regioselective acylation with fatty acids

DEFF Research Database (Denmark)

Lundt, Inge; Andersen, Søren Møller; Marcussen, Jan

1999-01-01

Regioselective acylation of 1,5-anhydro-D-fructose was performed with dodecanoic acid to give 1,5-anhydro-6-O-dodecanoyl-D-fructose, chemically in 50% yield and enzymatically in quantitative yield. Quantitative conversions were also obtained using hexadecanoic and octadecanoic acids as acyl donors...

Regioselective Acylation of Diols and Triols: The Cyanide Effect.

Science.gov (United States)

Peng, Peng; Linseis, Michael; Winter, Rainer F; Schmidt, Richard R

2016-05-11

Central topics of carbohydrate chemistry embrace structural modifications of carbohydrates and oligosaccharide synthesis. Both require regioselectively protected building blocks that are mainly available via indirect multistep procedures. Hence, direct protection methods targeting a specific hydroxy group are demanded. Dual hydrogen bonding will eventually differentiate between differently positioned hydroxy groups. As cyanide is capable of various kinds of hydrogen bonding and as it is a quite strong sterically nondemanding base, regioselective O-acylations should be possible at low temperatures even at sterically congested positions, thus permitting formation and also isolation of the kinetic product. Indeed, 1,2-cis-diols, having an equatorial and an axial hydroxy group, benzoyl cyanide or acetyl cyanide as an acylating agent, and DMAP as a catalyst yield at -78 °C the thermodynamically unfavorable axial O-acylation product; acyl migration is not observed under these conditions. This phenomenon was substantiated with 3,4-O-unproteced galacto- and fucopyranosides and 2,3-O-unprotected mannopyranosides. Even for 3,4,6-O-unprotected galactopyranosides as triols, axial 4-O-acylation is appreciably faster than O-acylation of the primary 6-hydroxy group. The importance of hydrogen bonding for this unusual regioselectivity could be confirmed by NMR studies and DFT calculations, which indicate favorable hydrogen bonding of cyanide to the most acidic axial hydroxy group supported by hydrogen bonding of the equatorial hydroxy group to the axial oxygen. Thus, the "cyanide effect" is due to dual hydrogen bonding of the axial hydroxy group which enhances the nucleophilicity of the respective oxygen atom, permitting an even faster reaction for diols than for mono-ols. In contrast, fluoride as a counterion favors dual hydrogen bonding to both hydroxy groups leading to equatorial O-acylation.

Sports Dehydration Safety Tips

Science.gov (United States)

Sports Dehydration Safety Tips Everything you need to know to keep your kids safe from dehydration when playing sports. To keep kids in top ... to stay hydrated by drinking plenty of fluids. Dehydration occurs when a body loses more water than ...

Catalyst Influence on Undesired Side Reactions in the Polycondensation of Fully Bio-Based Polyester Itaconates

Directory of Open Access Journals (Sweden)

Ina Schoon

2017-12-01

Full Text Available Bio-based unsaturated polyester resins derived from itaconic acid can be an alternative to established resins of this type in the field of radical-curing resins. However, one of the challenges of these polyester itaconates is the somewhat more elaborate synthetic process, especially under polycondensation conditions used on an industrial scale. The α,β-unsaturated double bond of the itaconic acid is prone to side reactions that can lead to the gelation of the polyester resin under standard conditions. This is especially true when bio-based diols such as 1,3-propanediol or 1,4-butanediol are used to obtain resins that are 100% derived from renewable resources. It was observed in earlier studies that high amounts of these aliphatic diols in the polyester lead to low conversion and gelation of the resins. In this work, a catalytic study using different diols was performed in order to elucidate the reasons for this behavior. It was shown that the choice of catalyst has a crucial influence on the side reactions occurring during the polycondensation reactions. In addition, the side reactions taking place were identified and suppressed. These results will allow for the synthesis of polyester itaconates on a larger scale, setting the stage for their industrial application.

FY 1999 research and development of technologies for creating original high-function materials. Development of technologies for functionalized materials for power generating facilities (Report on the R and D results of controlling precise structures of polycondesed systems); 1999 nendo dokusoteki kokino zairyo sosei gijutsu no kenkyu kaihatsu seika hokokusho. Hatsuden shisetsuyo koseinoka zairyo gijutsu kaihatsu (shukugokei seimitsu kozo seigyo no kenkyu kaihatsu)

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

The research and development project is implemented for the polymerization catalysts and precise polymerization processes which can freely control the primary structures, e.g., molecular weight, regularity, branching and terminal group structures, of the polymers produced by polycondensation and ring-opening polymerization, in order to drastically improve their functions, and the FY 1999 results are reported. The basic studies on the precise polycondensation successfully lead to chemoselective synthesis of polymers by the direct polymerization, and synthesis of polyamides of narrow molecular weight distribution and high-molecular-weight aliphatic polyesters. The other items studied include precisely, regularly sequential polymerization by amine activation, innovative synthesis of polycarbonate, precise control of branching structures, regioselective oxidative coupling polymerization, and matrix polycondensation. The basic studies on the controlled ring-opening polymerization cover cationic ring-opening polymerization behavior of 6-membered thiocarbonate derivative having an ester group, to generalize the polymerization controlled by neighboring group participation. The other items studied include precise control of branching structures, molecular weights, network polymer structures, and polymer unit sequences. (NEDO)

Rhodium-catalyzed Chemo- and Regioselective Cross-dimerization of Two Terminal Alkynes

Science.gov (United States)

Xu, Hua-Dong; Zhang, Ren-Wei; Li, Xiaoxun; Huang, Suyu; Tang, Weiping; Hu, Wen-Hao

2013-01-01

Cross-dimerization of terminal arylacetylenes and terminal propargylic alcohols/amides has been achieved in the effect of a rhodium catalyst. This method features high chemo- and regioselectivities rendering convenient and atom economical access to functionalized enynes. PMID:23356993

Room-temperature Pd-catalyzed C-H chlorination by weak coordination: one-pot synthesis of 2-chlorophenols with excellent regioselectivity.

Science.gov (United States)

Sun, Xiuyun; Sun, Yonghui; Zhang, Chao; Rao, Yu

2014-02-07

A room-temperature Pd(II)-catalyzed regioselective chlorination reaction has been developed for a facile one-pot synthesis of a broad range of 2-chlorophenols. The reaction demonstrates an excellent regioselectivity and reactivity for C-H chlorination. This reaction represents one of the rare examples of mild C-H functionalization at ambient temperature.

Regioselectivity of tributyltin ether mediated alkylations. A 119Sn and 13C NMR study

International Nuclear Information System (INIS)

Cruzado, C.; Bernabe, M.; Martin-Lomas, M.

1989-01-01

The 119 Sn and 13 C NMR spectra of the stannylated species resulting from the treatment of conformationally rigid polyhydroxylated compounds with bis(tributyltin) oxide have been determined and the effect of N-methylimidazole, added as catalyst in tributyltin ether mediated regioselective alkylations, has been investigated. The observed signal intensity changes, upfield shifts, signal broadenings, and the results of variable temperature experiments have been interpreted as indicative of the selective formation of pentacoordinated tin species, involving conveniently disposed adjacent hydroxyl groups, on addition of the catalyst. On these bases, a mechanistic hypothesis for the observed regioselectivity of N-methylimidazole-catalyzed tributyltin ether mediated benzylations is proposed. 13 references, 5 tables

Dehydration: physiology, assessment, and performance effects.

Science.gov (United States)

Cheuvront, Samuel N; Kenefick, Robert W

2014-01-01

This article provides a comprehensive review of dehydration assessment and presents a unique evaluation of the dehydration and performance literature. The importance of osmolality and volume are emphasized when discussing the physiology, assessment, and performance effects of dehydration. The underappreciated physiologic distinction between a loss of hypo-osmotic body water (intracellular dehydration) and an iso-osmotic loss of body water (extracellular dehydration) is presented and argued as the single most essential aspect of dehydration assessment. The importance of diagnostic and biological variation analyses to dehydration assessment methods is reviewed and their use in gauging the true potential of any dehydration assessment method highlighted. The necessity for establishing proper baselines is discussed, as is the magnitude of dehydration required to elicit reliable and detectable osmotic or volume-mediated compensatory physiologic responses. The discussion of physiologic responses further helps inform and explain our analysis of the literature suggesting a ≥ 2% dehydration threshold for impaired endurance exercise performance mediated by volume loss. In contrast, no clear threshold or plausible mechanism(s) support the marginal, but potentially important, impairment in strength, and power observed with dehydration. Similarly, the potential for dehydration to impair cognition appears small and related primarily to distraction or discomfort. The impact of dehydration on any particular sport skill or task is therefore likely dependent upon the makeup of the task itself (e.g., endurance, strength, cognitive, and motor skill). © 2014 American Physiological Society.

Solvent-dependent regioselective oxidation of trans-chalcones using aqueous hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Peng, Wang; Jiabin, Yang; Lushen, Li, E-mail: jimin@seu.edu.cn [Southeast University, Nanjing (China). School of Biological Science and Medical Engineering; Jin, Cai; Chunlong, Sun; Min, Ji [Southeast University, Nanjing (China). School of Chemistry and Chemical Engineering

2013-03-15

A novel method for regioselective oxidation of trans-chalcones with hydrogen peroxide in acetonitrile to afford cinnamic acids is reported. Only trans-b-arylacrylic acids were observed. A wide range of functionalized products can be effectively produced from various chalcones in good to excellent yields. (author)

A Novel and Highly Regioselective Synthesis of New Carbamoylcarboxylic Acids from Dianhydrides

Directory of Open Access Journals (Sweden)

Adrián Ochoa-Terán

2014-01-01

Full Text Available A regioselective synthesis has been developed for the preparation of a series of N,N′-disubstituted 4,4′-carbonylbis(carbamoylbenzoic acids and N,N′-disubstituted bis(carbamoyl terephthalic acids by treatment of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (1 and 1,2,4,5-benzenetetracarboxylic dianhydride (2 with arylalkyl primary amines (A-N. The carbamoylcarboxylic acid derivatives were synthesized with good yield and high purity. The specific reaction conditions were established to obtain carbamoyl and carboxylic acid functionalities over the thermodynamically most favored imide group. Products derived from both anhydrides 1 and 2 were isolated as pure regioisomeric compounds under innovative experimental conditions. The chemo- and regioselectivity of products derived from dianhydrides were determined by NMR spectroscopy and confirmed by density functional theory (DFT. All products were characterized by NMR, FTIR, and MS.

Role of ligands in controlling the regioselectivity in ruthenium ...

Indian Academy of Sciences (India)

of Hay and Wadt (LANL2DZ)11 for ruthenium atom and 6-31G(d)12 for other .... C2 atom in 3x/3′ x. To understand the wider role of lig- ands in modulating the regio-selectivity of product for- mation, we have studied the benzoic acid addition to the selected .... at C1 and the localization of electron density in the. M=C double ...

Dehydration in the Older Adult.

Science.gov (United States)

Miller, Hayley J

2015-09-01

Dehydration affects 20% to 30% of older adults. It has a greater negative outcome in this population than in younger adults and increases mortality, morbidity, and disability. Dehydration is often caused by water deprivation in older adults, although excess water loss may also be a cause. Traditional markers for dehydration do not take into consideration many of the physiological differences present in older adults. Clinical assessment of dehydration in older adults poses different findings, yet is not always diagnostic. Treatment of dehydration should focus on prevention and early diagnosis before it negatively effects health and gives rise to comorbidities. The current article discusses what has most thoroughly been studied; the best strategies and assessment tools for evaluation, diagnosis, and treatment of dehydration in older adults; and what needs to be researched further. [Journal of Gerontological Nursing, 41(9), 8-13.]. Copyright 2015, SLACK Incorporated.

Iridium-Catalyzed Regioselective Borylation of Substituted Biaryls

KAUST Repository

Chotana, Ghayoor

2018-03-28

Biarylboronic esters are generally prepared by directed ortho­ -metalation or by Miyaura borylation and hence rely on the presence of a directing group or pre-functionalization. In this paper, the preparation of biarylboronic esters by direct C–H borylation of biaryl substrates is reported. Sterically governed regioselectivities were observed in the borylation of appropriately substituted biaryls by using [Ir(OMe)(COD)] precatalyst and di- tert -butylbipyridyl ligand. The resulting biarylboronic esters were isolated in 38–98% yields. The synthesized biarylboronic esters were further successfully employed in C–O, C–Br, and C–C coupling reactions.

Dehydration behaviour of hydrates

Energy Technology Data Exchange (ETDEWEB)

Dette, S.S.; Stelzer, T.; Jones, M.J.; Ulrich, J. [Martin-Luther-Universitaet Halle-Wittenberg, Zentrum fuer Ingenieurwissenschaften, Verfahrenstechnik/TVT, 06099 Halle (Germany)

2010-07-15

Immersing a crystalline solvate in a suitable anti-solvent can induce phase transformation to solvent-free solid phase. In certain cases the solvent-mediated phase transition results in the generation of hollow, tubular structures. Both the tube dimensions of sodium-2-keto-L-gulonate anhydrate (skga) and the dehydration kinetics of sodium-2-keto-L-gulonate monohydrate (skgm) can be modified by the antisolvent employed. An explanation for the variable dehydration behaviour of skgm in the antisolvents is presented here. Furthermore, other crystalline hydrates were dehydrated in dry methanol. Providing an operational window can be found, any hydrate material could possibly find use in the production of tubes (micro- or nanotubes for different applications). The experimental conditions selected (dry methanol as antisolvent, dehydration temperature at 25 C) for the dehydration did not lead to the anhydrate tube growth for all hydrates investigated. Based upon the results presented here a first hypothesis is presented to explain this effect. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Electronic forces as descriptors of nucleophilic and electrophilic regioselectivity and stereoselectivity.

Science.gov (United States)

Liu, Shubin; Rong, Chunying; Lu, Tian

2017-01-04

One of the main tasks of theoretical chemistry is to rationalize computational results with chemical insights. Key concepts of such nature include nucleophilicity, electrophilicity, regioselectivity, and stereoselectivity. While computational tools are available to predict barrier heights and other reactivity properties with acceptable accuracy, a conceptual framework to appreciate above quantities is still lacking. In this work, we introduce the electronic force as the fundamental driving force of chemical processes to understand and predict molecular reactivity. It has three components but only two are independent. These forces, electrostatic and steric, can be employed as reliable descriptors for nucleophilic and electrophilic regioselectivity and stereoselectivity. The advantages of using these forces to evaluate molecular reactivity are that electrophilic and nucleophilic attacks are featured by distinct characteristics in the electrostatic force and no knowledge of quantum effects included in the kinetic and exchange-correlation energies is required. Examples are provided to highlight the validity and general applicability of these reactivity descriptors. Possible applications in ambident reactivity, σ and π holes, frustrated Lewis pairs, and stereoselective reactions are also included in this work.

Regioselective Galactofuranosylation for the Synthesis of Disaccharide Patterns Found in Pathogenic Microorganisms.

Science.gov (United States)

Legentil, Laurent; Cabezas, Yari; Tasseau, Olivier; Tellier, Charles; Daligault, Franck; Ferrières, Vincent

2017-07-21

Koenigs-Knorr glycosylation of acceptors with more than one free hydroxyl group by 2,3,5,6-tetrabenzoyl galactofuranosyl bromide was performed using diphenylborinic acid 2-aminoethyl ester (DPBA) as inducer of regioselectivity. High regioselectivity for the glycosylation on the equatorial hydroxyl group of the acceptor was obtained thanks to the transient formation of a borinate adduct of the corresponding 1,2-cis diol. Nevertheless formation of orthoester byproducts hampered the efficiency of the method. Interestingly electron-withdrawing groups on O-6 or on C-1 of the acceptor displaced the reaction in favor of the desired galactofuranosyl containing disaccharide. The best yield was obtained for the furanosylation of p-nitrophenyl 6-O-acetyl mannopyranoside. Precursors of other disaccharides, found in the glycocalix of some pathogens, were synthesized according to the same protocol with yields ranging from 45 to 86%. This is a good alternative for the synthesis of biologically relevant glycoconjugates.

Regioselective Nucleophilic Ring Opening of Epoxides and Aziridines derived from Homoallylic Alcohols

DEFF Research Database (Denmark)

Tanner, David Ackland; Groth, Thomas

1997-01-01

The regioselectivity of nucleophilic ring opening of some 3,4-epoxy and 3,4-aziridino alcohols has been studied. The nucleophiles chosen were complex hydrides (LiAlH4, Red-Al and DIBAL) and Lipshutz- or Gilman-type organocuprate reagents. The C-4 substituent in the substrates was varied in order...... to study steric and electronic effects on the ring opening reactions. For alkyl substituents at C-4, most of the results can be explained on the basis of intramolecular delivery of the nucleophile to C-3 via a six-membered transition state, leading to 1,4-diols or 1,4-amino alcohol derivatives. In general......, the epoxy alcohols gave poorer regioselectivity than the N-tosyl aziridino alcohols, for which selectivities of >95:5 were routinely obtained. The activating effect of a phenyl group at C-4 led to a switch in regiochemistry, with the 1,3-diol or 1,3-amino alcohol derivative as the major product. (C) 1997...

Interfacial Polycondensation Synthesis of Optically Sensitive Polyurea Microcapsule

Directory of Open Access Journals (Sweden)

Weidong Lai

2014-01-01

Full Text Available TMPTA prepolymer resin and photoinitiators of ITX/TPO had been encapsulated in core-shell structured microcapsules as optical responding ingredients based on interfacial polycondensation method, and polyurea structured microcapsule shell had been formed on the sheared O/W interface. The synthesized microcapsule had regular core-shell structure with the diameter of about 0.455 μm and shell thickness of about 40 nm. UV-visible absorption spectra indicated that the encapsulated ITX and TPO photoinitiators could efficiently absorb UV irradiation. Under exposure, the C=C bonds absorbance of the microencapsulated TMPTA decreased rapidly and then nearly unchanged during further exposure after 30 s. This implied that the optical response was achieved by C=C bond cleavage of TMPTA monomer initiated by the photoinitiator radicals, to form network polymers in microcapsules. The relative crosslinking rate was about 50%. Due to core polymer formation, the thermal phase change temperature of exposed microcapsules was narrowed and ranged from 105 to 205°C, compared with that from 125 to 260°C of unexposed microcapsules. Furthermore, the image density decrease at longer irradiation time had also verified the optical responding function of the synthesized microcapsules in macroscopic viewpoint.

Synthesis and characterization of poly(ester amide from remewable resources through melt polycondensation

Directory of Open Access Journals (Sweden)

B. B. Wang

2014-01-01

Full Text Available Biodegradable poly(ester amides (PEAs were synthesized from lactic acid and 11-aminoundecanoic acid via melt polycondensation. Molecular weights, chemical structures and thermal properties of the poly(ester amides were characterized in terms of gel permeation chromatography (GPC, Fourier transform infrared spectroscopy (FTIR, 1H nuclear magnetic resonance (1H NMR, differential scanning calorimetry (DSC and thermogravimetric analysis (TGA, respectively. The PEAs have low molecular weights and display a lower cold crystallization temperature as well as smaller crystallinity by comparison with the pure poly(lactic acid (PLA. The incorporation of the 11-aminoundecanoic acid into the PLA chain not only improved the thermal stability but changed the decomposition process.

Salmonella survival during thermal dehydration of fresh garlic and storage of dehydrated garlic products.

Science.gov (United States)

Zhang, Hongmei; Qi, Yan; Wang, Lei; Zhang, Shaokang; Deng, Xiangyu

2017-12-18

Salmonella survival was characterized and modeled during thermal dehydration of fresh garlic and storage of dehydrated garlic products. In our experiments that simulated commercial dehydration processing at 80±5°C, moderate level of Salmonella contamination (4-5logCFU/g) on fresh garlic was reduced below the enumeration limit (1.7logCFU/g) after 4.5h of dehydration and not detectable by culture enrichment after 7h. With high level of contamination (7-8logCFU/g), the Salmonella population persisted at 3.6logCFU/g after 8h of processing. By increasing the dehydration temperature to 90±5°C, the moderate and high levels of initial Salmonella load on fresh garlic dropped below the enumeration limit after 1.5 and 3.75h of processing and became undetectable by culture enrichment after 2.5 and 6h, respectively. During the storage of dried garlic products, Salmonella was not able to grow under all tested combinations of temperature (25 and 35°C) and water activity (0.56-0.98) levels, suggesting active inhibition. Storage temperature played a primary role in determining Salmonella survival on dehydrated garlic flakes. Under a typical storage condition at 25°C and ambient relative humidity, Salmonella could persist over months with the population gradually declining (4.3 log reduction over 88days). Granular size of dehydrated garlic had an impact on Salmonella survival, with better survival of the pathogen observed in bigger granules. At the early stage of dehydrated garlic storage (until 7days), rising water activity appeared to initially promote but then inhibited Salmonella survival, resulting in a water activity threshold at 0.73 where Salmonella displayed strongest persistence. However, this phenomenon was less apparent during extended storage (after 14days). Copyright © 2017 Elsevier B.V. All rights reserved.

Water-loss dehydration and aging.

Science.gov (United States)

Hooper, Lee; Bunn, Diane; Jimoh, Florence O; Fairweather-Tait, Susan J

2014-01-01

This review defines water-loss and salt-loss dehydration. For older people serum osmolality appears the most appropriate gold standard for diagnosis of water-loss dehydration, but clear signs of early dehydration have not been developed. In older adults, lower muscle mass, reduced kidney function, physical and cognitive disabilities, blunted thirst, and polypharmacy all increase dehydration risk. Cross-sectional studies suggest a water-loss dehydration prevalence of 20-30% in this population. Water-loss dehydration is associated with higher mortality, morbidity and disability in older people, but evidence is still needed that this relationship is causal. There are a variety of ways we may be able to help older people reduce their risk of dehydration by recognising that they are not drinking enough, and being helped to drink more. Strategies to increase fluid intake in residential care homes include identifying and overcoming individual and institutional barriers to drinking, such as being worried about not reaching the toilet in time, physical inability to make or to reach drinks, and reduced social drinking and drinking pleasure. Research needs are discussed, some of which will be addressed by the FP7-funded NU-AGE (New dietary strategies addressing the specific needs of elderly population for a healthy ageing in Europe) trial. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

A simple, effective, green method for regioselective 3-acylation of unprotected indoles

DEFF Research Database (Denmark)

Tran, Phuong Huong; Tran, Hai N.; Hansen, Poul Erik

2015-01-01

A fast and green method is developed for regioselective acylation of indoles in the 3-position without the need for protection of the NH position. The method is based on Friedel-Crafts acylation using acid anhydrides. The method has been optimized, and Y(OTf)3 in catalytic amounts is found...

Device to control the desalination and dehydration process for petroleum in an electro-dehydrator

Energy Technology Data Exchange (ETDEWEB)

Kusowskii, B I; Pawlow, N I; Matiitschenko, A P; Sacharow, S A; Kirilin, A F

1976-01-22

The invention deals with a device to control the desalination and dehydration processes for petroleum in electro-dehydrators. In the latter, the water-petroleum emulsion introduced is separated by an electric field into petroleum and salt water. Regulation of the dehydration and desalination process by means of the current difference of two circuits in the emulgator, in which this difference controls the controlling unit of a regulating valve, via which salt water and dirt remains are removed from the dehydrator, is known. This device, however, is not immune to disturbance, as when changing the water content of the emulsion, spark-overs may occur between one electrode and the surface of the separated salt water. This disturbance is removed according to the invention in that the abrupt changes of current prior to the spark-over cause a forcibly increased through-flow amount of discharging salt water and dirt remains for a certain time and thus prevent the full formation of an electric spark-over disturbing the operation of the dehydrator.

Regioselective oxyalkylation of vinylarenes catalyzed by diatomite-supported manganese oxide nanoparticles.

Science.gov (United States)

Sun, Huayin; Zhang, Yonghui; Guo, Fengfeng; Zha, Zhenggen; Wang, Zhiyong

2012-04-06

A regioselective oxyalkylation reaction of vinylarenes with cyclic ethers was developed under the catalysis of a new heterogeneous catalyst, the diatomite-supported Mn(3)O(4) nanoparticles (SMONP-1). The use of this heterogeneous catalyst provided a novel approach for the synthesis of α-carbonyled β-alkylated aryl derivatives via a sp(3) C-H bond functionalization under mild aerobic conditions.

Dehydration

Science.gov (United States)

... dehydration also may differ by age. Infant or young child Dry mouth and tongue No tears when ... Clinic does not endorse any of the third party products and services advertised. Advertising and sponsorship policy ...

Regioselective conversion of primary alcohols into iodides in unprotected methyl furanosides and pyranosides

DEFF Research Database (Denmark)

Skaanderup, Philip Robert; Poulsen, Carina Storm; Hyldtoft, Lene

2002-01-01

Two methods are described for the regioselective displacement of the primary hydroxy group in methyl glycosides with iodide. The first method is a modification of a literature procedure employing triphenylphosphine and iodine, where purification has been carried out on a reverse phase column in o...

Evaluation and Management of Dehydration in Children.

Science.gov (United States)

Santillanes, Genevieve; Rose, Emily

2018-05-01

The article discusses the evaluation of dehydration in children and reviews the literature on physical findings of dehydration. Pediatric dehydration is a common problem in emergency departments and wide practice variation in treatment exists. Dehydration can be treated with oral, nasogastric, subcutaneous, or intravenous fluids. Although oral rehydration is underutilized in the United States, most children with dehydration can be successfully rehydrated via the oral route. Selection of oral rehydration solution and techniques for successful oral rehydration are presented. Appropriate selection and rate of administration of intravenous fluids are also discussed for isonatremic, hyponatremic, and hypernatremic dehydration. Copyright © 2017 Elsevier Inc. All rights reserved.

Orthogonal protection of saccharide polyols through solvent-free one-pot sequences based on regioselective silylations

Directory of Open Access Journals (Sweden)

Serena Traboni

2016-12-01

Full Text Available tert-Butyldimethylsilyl (TBDMS and tert-butyldiphenylsilyl (TBDPS are alcohol protecting groups widely employed in organic synthesis in view of their compatibility with a wide range of conditions. Their regioselective installation on polyols generally requires lengthy reactions and the use of high boiling solvents. In the first part of this paper we demonstrate that regioselective silylation of sugar polyols can be conducted in short times with the requisite silyl chloride and a very limited excess of pyridine (2–3 equivalents. Under these conditions, that can be regarded as solvent-free conditions in view of the insolubility of the polyol substrates, the reactions are faster than in most examples reported in the literature, and can even be further accelerated with a catalytic amount of tetrabutylammonium bromide (TBAB. The strategy proved also useful for either the selective TBDMS protection of secondary alcohols or the fast per-O-trimethylsilylation of saccharide polyols. In the second part of the paper the scope of the silylation approach was significantly extended with the development of unprecedented “one-pot” and “solvent-free” sequences allowing the regioselective silylation/alkylation (or the reverse sequence of saccharide polyols in short times. The developed methodologies represent a very useful and experimentally simple tool for the straightforward access to saccharide building-blocks useful in organic synthesis.

[Dehydration due to "mouth broken"].

Science.gov (United States)

Meijler, D P M; van Mossevelde, P W J; van Beek, R H T

2012-09-01

Two children were admitted to a medical centre due to dehydration after an oral injury and the extraction of a tooth. One child complained of "mouth broken". Dehydration is the most common water-electrolyte imbalance in children. Babies and young children are prone to dehydration due to their relatively large body surface area, the high percentage extracellular fluid, and the limited ability of the kidneys to conserve water. After the removal ofa tooth, after an oral trauma or in case of oral discomfort, a child is at greater risk of dehydration by reduced fluid and food intake due to oral pain and/or discomfort and anxiety to drink. In those cases, extra attention needs to be devoted to the intake of fluids.

Comparison of clinical and biochemical markers of dehydration with the clinical dehydration scale in children: a case comparison trial.

Science.gov (United States)

Tam, Ron K; Wong, Hubert; Plint, Amy; Lepage, Nathalie; Filler, Guido

2014-06-16

The clinical dehydration scale (CDS) is a quick, easy-to-use tool with 4 clinical items and a score of 1-8 that serves to classify dehydration in children with gastroenteritis as no, some or moderate/severe dehydration. Studies validating the CDS (Friedman JN) with a comparison group remain elusive. We hypothesized that the CDS correlates with a wide spectrum of established markers of dehydration, making it an appropriate and easy-to-use clinical tool. This study was designed as a prospective double-cohort trial in a single tertiary care center. Children with diarrhea and vomiting, who clinically required intravenous fluids for rehydration, were compared with minor trauma patients who required intravenous needling for conscious sedation. We compared the CDS with clinical and urinary markers (urinary electrolytes, proteins, ratios and fractional excretions) for dehydration in both groups using receiver operating characteristic (ROC) curves to determine the area under the curve (AUC). We enrolled 73 children (male = 36) in the dehydration group and 143 (male = 105) in the comparison group. Median age was 32 months (range 3-214) in the dehydration and 96 months (range 2.6-214 months, p dehydration group and 0 in the comparison group (p dehydrated group: difference in heart rate, diastolic blood pressure, urine sodium/potassium ratio, urine sodium, fractional sodium excretion, serum bicarbonate, and creatinine measurements. The best markers for dehydration were urine Na and serum bicarbonate (ROC AUC = 0.798 and 0.821, respectively). CDS was most closely correlated with serum bicarbonate (Pearson r = -0.3696, p = 0.002). Although serum bicarbonate is not the gold standard for dehydration, this study provides further evidence for the usefulness of the CDS as a dehydration marker in children. Registered at ClinicalTrials.gov (NCT00462527) on April 18, 2007.

Delocalization model of regioselectivity and reactivity of free radicals in reactions of addition to olefins

International Nuclear Information System (INIS)

Volovik, S.V.; Dyadyusha, G.G.; Staninets, V.I.

1987-01-01

On the basis of the concept of polarity (philicity) of free radicals as proposed by the authors, within the framework of methods of qualitative surfaces of potential energy (linear combinations of configurations of fragments) and stabilization energy, an effective model has been developed for the regioselectivity and reactivity of radicals in processes of addition. A critical examination is made of certain key aspects of the change in regiochemistry and reactivity with changes in the electronic structure of the free radical and substrate. The dominant trends in regioselectivity and reactivity in processes of free-radical addition to olefins are controlled by electronic effects and can be predicted by analyzing interactions of diabatic potential energy surfaces or orbital interactions for a system consisting of a free radical and an unsaturated substrate

The diagnostic accuracy of Clinical Dehydration Scale in identifying dehydration in children with acute gastroenteritis: a systematic review.

Science.gov (United States)

Falszewska, Anna; Dziechciarz, Piotr; Szajewska, Hania

2014-10-01

To systematically update diagnostic accuracy of the Clinical Dehydration Scale (CDS) in clinical recognition of dehydration in children with acute gastroenteritis. Six databases were searched for diagnostic accuracy studies in which population were children aged 1 to 36 months with acute gastroenteritis; index test was the CDS; and reference test was post-illness weight gain. Three studies involving 360 children were included. Limited evidence showed that in high-income countries the CDS provides strong diagnostic accuracy for ruling in moderate and severe (>6%) dehydration (positive likelihood ratio 5.2-6.6), but has limited value for ruling it out (negative likelihood ratio 0.4-0.55). In low-income countries, the CDS has limited value either for ruling moderate or severe dehydration in or out. In both settings, the CDS had limited value for ruling in or out dehydration dehydration 3% to 6%. The CDS can help assess moderate to severe dehydration in high-income settings. Given the limited data, the evidence should be viewed with caution. © The Author(s) 2014.

Rhodium-catalyzed chemo- and regioselective decarboxylative addition of β-ketoacids to alkynes.

Science.gov (United States)

Li, Changkun; Grugel, Christian P; Breit, Bernhard

2016-04-30

A highly efficient rhodium-catalyzed chemo- and regioselective addition of β-ketoacids to alkynes is reported. Applying a Rh(i)/(S,S)-DIOP catalyst system, γ,δ-unsaturated ketones were prepared with exclusively branched selectivity under mild conditions. This demonstrates that readily available alkynes can be an alternative entry to allyl electrophiles in transition-metal catalyzed allylic alkylation reactions.

Regioselective annulation of nitrosopyridine with alkynes: straightforward synthesis of N-oxide-imidazopyridines.

Science.gov (United States)

Manna, Srimanta; Narayan, Rishikesh; Golz, Christopher; Strohmann, Carsten; Antonchick, Andrey P

2015-04-11

We have developed a novel method for the regioselective annulation of 2-nitrosopyridines with variably substituted alkynes under mild reaction conditions. This approach allows the annulation of alkynes with 2-nitrosopyridines under reagent- and catalyst-free reaction conditions. The developed method shows excellent functional group tolerance and provides easy access to N-oxide-imidazo[1,2-a]pyridines.

Regioselective alkane hydroxylation with a mutant AlkB enzyme

Science.gov (United States)

Koch, Daniel J.; Arnold, Frances H.

2012-11-13

AlkB from Pseudomonas putida was engineered using in-vivo directed evolution to hydroxylate small chain alkanes. Mutant AlkB-BMO1 hydroxylates propane and butane at the terminal carbon at a rate greater than the wild-type to form 1-propanol and 1-butanol, respectively. Mutant AlkB-BMO2 similarly hydroxylates propane and butane at the terminal carbon at a rate greater than the wild-type to form 1-propanol and 1-butanol, respectively. These biocatalysts are highly active for small chain alkane substrates and their regioselectivity is retained in whole-cell biotransformations.

Regioselective synthesis of isoxazole-mercaptobenzimidazole hybrids and their in vivo analgesic and anti-inflammatory activity studies

DEFF Research Database (Denmark)

Kankala, Shravankumar; Kankala, Ranjith Kumar; Gundepaka, Prasad

2013-01-01

Regioselective synthesis of isoxazole-mercaptobenzimidazole hybrids and their efficiency in in vivo analgesic and anti-inflammatory activity was described. A comparison of structure-activity relationship for there compounds was also emphasized....

THERAPY OF DIARRHEA AND DEHYDRATION IN CHILDREN

OpenAIRE

E.G. Tsymbalova; R.F. Tepaev

2011-01-01

Dehydration is one of the leading causes of mortality in children. The most frequent cause of dehydration in children is diarrhea syndrome. Timely differential diagnostics of etiological causes, assessment of severity, dehydration type are critical conditions of successful therapy of diarrhea syndrome. The article provides modern recommendations on diagnostics and treatment of dehydration depending on the type and severity, on correction of electrolyte abnormalities. The authors also highligh...

Reactivity and Regioselectivity in the Heck Reaction - A Hammett Study of 4-Substituted Styrenes

DEFF Research Database (Denmark)

Fristrup, Peter; Le Quement, Sebastian; Tanner, David Ackland

2004-01-01

The regioselectivity in the cationic Heck reaction of 4-substituted styrenes was addressed by a Hammett study. In this branching reaction, plots based on the substrate reactivity did not give meaningful data, whereas the product distribution was variable due to differing preferences for further...

Assessment of extracellular dehydration using saliva osmolality.

Science.gov (United States)

Ely, Brett R; Cheuvront, Samuel N; Kenefick, Robert W; Spitz, Marissa G; Heavens, Kristen R; Walsh, Neil P; Sawka, Michael N

2014-01-01

When substantial solute losses accompany body water an isotonic hypovolemia (extracellular dehydration) results. The potential for using blood or urine to assess extracellular dehydration is generally poor, but saliva is not a simple ultra-filtrate of plasma and the autonomic regulation of salivary gland function suggests the possibility that saliva osmolality (Sosm) may afford detection of extracellular dehydration via the influence of volume-mediated factors. This study aimed to evaluate the assessment of extracellular dehydration using Sosm. In addition, two common saliva collection methods and their effects on Sosm were compared. Blood, urine, and saliva samples were collected in 24 healthy volunteers during paired euhydration and dehydration trials. Furosemide administration and 12 h fluid restriction were used to produce extracellular dehydration. Expectoration and salivette collection methods were compared in a separate group of eight euhydrated volunteers. All comparisons were made using paired t-tests. The diagnostic potential of body fluids was additionally evaluated. Dehydration (3.1 ± 0.5% loss of body mass) decreased PV (-0.49 ± 0.12 L; -15.12 ± 3.94% change), but Sosm changes were marginal ( 0.05). Extracelluar dehydration was not detectable using plasma, urine, or saliva measures. Salivette and expectoration sampling methods produced similar, consistent results for Sosm, suggesting no methodological influence on Sosm.

Dehydration survival of crop plants and its measurement.

Science.gov (United States)

Blum, Abraham; Tuberosa, Roberto

2018-01-08

Dehydration survival under drought stress is defined in this review as the transition from plant activity into a quiescent state of life preservation, which will be terminated by either recovery or death, depending on the stress regime and the plant's resilience. Dehydration survival is a popular phenotype by which functional genomics attempts to test gene function in drought resistance and survival. The available reports on phenotyping and genotyping of dehydration survival in genomic studies indicate that the measurement of this trait is often biased to the extent that misguided interpretations are likely to occur. This review briefly discusses the physiological basis of dehydration survival in resurrection plants and crop plants, and concludes that in phenotyping dehydration survival there is a need to distinguish between dehydration avoidance and dehydration tolerance (also termed desiccation tolerance) in affecting survival and recovery. Without this distinction, functional genomics studies of the trait might be biased. Survival due to dehydration avoidance is expressed by the capacity to maintain a relatively high plant water status as the plant is desiccated. Survival due to dehydration tolerance is expressed by delayed mortality (mortality at a relatively low plant water status) as affected by the resilience of plant metabolism. The common test of dehydration survival, using the relative recovery after a given number of stress days, is therefore insufficient because it is mainly driven by dehydration avoidance and so ignores a possible role for dehydration tolerance. Conceivable methods for more accurate phenotyping of the two components of dehydration survival are proposed and discussed. © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The dehydration of uranyl nitrate hexahydrate

International Nuclear Information System (INIS)

Badalov, A.; Kamalov, D.D.; Khamidov, B.O.; Mirsaidov, I.U.; Eshbekov, N.R.

2010-01-01

Present article is devoted to study of dehydration process of uranyl nitrate hexahydrate. The dehydration process of uranyl nitrate hexahydrate was studied by means of tensimeter method with membrane zero-manometer. The research was carried out under equilibrium conditions. It was defined that in studied temperature ranges (300-450 K) the dehydration process of UO_2(NO_3)_2 has a three stage character.

The regioselectivity of glutathione adduct formation with flavonoid quinone methides is pH-dependent

NARCIS (Netherlands)

Awad, H.M.; Boersma, M.G.; Boeren, S.; Vervoort, J.; Bladeren, van P.J.; Rietjens, I.M.C.M.

2002-01-01

In the present study, the formation of glutathionyl adducts from a series of 3',4'-dihydroxy flavonoid o-quinone/p-quinone methides was investigated with special emphasis on the regioselectivity of the glutathione addition as a function of pH. The flavonoid o-quinones were generated using

Breastfeeding-associated hypernatraemic dehydration

Directory of Open Access Journals (Sweden)

Sónia Melo Gomes

2009-03-01

Full Text Available Objective: In the last few years there has been an increase in case reports of hypernatraemic dehydration in breastfed newborns. Insufficient intake has an important role in the pathophysiology of this condition. The aim of this study was to evaluate exclusively breastfed neonates admitted for hypernatraemic dehydration. Methods: Retrospective study of breastfed neonates diagnosed with hypernatraemic dehydration, between March 2002 and March 2008, in a level 1 maternity. Rresults: Nineteen cases were identified (0.44% of neonatal intermediate care hospitalizations, 53% of them were male. The annual distribution revealed a higher number of cases in 2008: 26.3% in only three months. Median birth weight was 3,000 g and the median gestational age was 38 weeks. Vaginal delivery was the most frequent form of birth (42%, and 79% of mothers were primiparas. Admissions were made through the emergency department in 68.4%. The main reasons for seeking medical attention were: poor oral intake (32%, weight loss (26%, and jaundice (26%. The median age at admission was four days. Percentage of weight loss: 6.7 to 40%, median was 11%. Dehydration signs were absent in 42% of the patients. Median Na+ values were 152 mEq/l. Jaundice was the most frequent comorbidity found (74%. Intravenous fluids were administered in 89% and acute neurological complications were found in 21%, there were no deaths. Cconclusions: Breastfeeding-associated hypernatraemic dehydration seems to be a consequence of breastfeeding difficulties in inexperienced mothers. Since many cases are paucisymptomatic, there should be a high level of suspicion, especially in those patients with jaundice.

Diagnostic accuracy of clinical dehydration scales in children.

Science.gov (United States)

Falszewska, Anna; Dziechciarz, Piotr; Szajewska, Hania

2017-08-01

The aim of this study was to evaluate the diagnostic accuracy of the Clinical Dehydration Scale (CDS), the World Health Organization (WHO) scale, and the Gorelick scale for dehydration assessment in children. A prospective, observational study was carried out between October 2014 and December 2016. Eligible participants were children aged 1 month to 5 years with acute diarrhea. After hospital admission, each patient's weight was recorded and the degree of dehydration based on three scales was assessed. The reference standard was the percentage weight change between the discharge and admission weights. The main outcomes were the sensitivity, specificity, positive likelihood ratio (LR), and negative LR. Of 128 children enrolled in the study, complete data were available from 118 patients for analysis. Most of children presented with no or mild dehydration. Only the CDS showed limited value in confirming a diagnosis of dehydration ≥6% (positive LR 3.9, 95% CI 1.1 to 9.1), with no value in ruling it out (negative LR 0.6, 95% CI 0.2 to 0.99). In our cohort, the CDS was of limited diagnostic value in ruling in severe dehydration in children with acute gastroenteritis. The WHO and Gorelick scales were not helpful in the assessment of dehydration. What is Known : • Treatment of acute gastroenteritis (AGE) is based on assessing and correcting the degree of dehydration. • Several scales combining various signs and symptoms have been developed, including the Clinical Dehydration Scale (CDS), and the World Health Organization (WHO) scale, and the Gorelick scale. None of these scales is internationally accepted for best accuracy in diagnosing dehydration in children. What is New: • The CDS was of limited diagnostic value in ruling in severe dehydration in children with AGE. • The WHO and Gorelick scales were not helpful in the assessment of dehydration.

Insights into regioselective metabolism of mefenamic acid by cytochrome P450 BM3 mutants through crystallography, docking, molecular dynamics, and free energy calculations

DEFF Research Database (Denmark)

Capoferri, Luigi; Leth, Rasmus; Ter Haar, Ernst

2016-01-01

of the protein mutant M11 was expressed, purified, and crystallized, and its X-ray structure was used as template for modeling. A multistep approach was used that combines molecular docking, molecular dynamics (MD) simulation, and binding free-energy calculations to address protein flexibility. In this way...... active-site mutations such as V87I were reported to invert regioselectivity in NSAID hydroxylation. In this work, we combine crystallography and molecular simulation to study the effect of single mutations on binding and regioselective metabolism of mefenamic acid by M11 mutants. The heme domain...... of mefenamic acid by M11 and its mutants by including protein flexibility and dynamics in free-energy computation. In addition, we could obtain structural insights into the change in regioselectivity of mefenamic acid hydroxylation due to single active-site mutations. Our findings confirm that use of MD...

Regioselectivity in lithiation of 1-methylpyrazole: experimental, density functional theory and multinuclear NMR study

DEFF Research Database (Denmark)

Balle, Thomas; Begtrup, Mikael; Jaroszewski, Jerzy W.

2006-01-01

-position. The observed regioselectivity can be correctly predicted, at least qualitatively, using density functional B3LYP/6-31+G(d,p) calculations only when solvation effects (IEFPCM) are taken into account. The 1H,6Li HOESY and NOESY NMR spectra of the thermodynamic product 5-lithio-1-methylpyrazole (5...

Regioselective Alcoholysis of Silychristin Acetates Catalyzed by Lipases

Directory of Open Access Journals (Sweden)

Eva Vavříková

2015-05-01

Full Text Available A panel of lipases was screened for the selective acetylation and alcoholysis of silychristin and silychristin peracetate, respectively. Acetylation at primary alcoholic group (C-22 of silychristin was accomplished by lipase PS (Pseudomonas cepacia immobilized on diatomite using vinyl acetate as an acetyl donor, whereas selective deacetylation of 22-O-acetyl silychristin was accomplished by Novozym 435 in methyl tert-butyl ether/ n-butanol. Both of these reactions occurred without diastereomeric discrimination of silychristin A and B. Both of these enzymes were found to be capable to regioselective deacetylation of hexaacetyl silychristin to afford penta-, tetra- and tri-acetyl derivatives, which could be obtained as pure synthons for further selective modifications of the parent molecule.

Downhole dehydration - status report and implementation study; Downhole Dehydration - Statusbericht und Umsetzungsstudie

Energy Technology Data Exchange (ETDEWEB)

Jacobs, D.; Schmidt, D. [BEB Erdgas und Erdoel GmbH, Hannover (Germany)

1998-12-31

Downhole dehydration, i.e. in-situ separation of water and oil, is an interesting new technology. The contribution describes the technology and the results of a field experiment. (orig.) [Deutsch] Die Tail-End Foerderphase in der deutschen Erdoelproduktion, welche durch hohe Wasserhebekosten gekennzeichnet ist, erfordert zur Aufrechterhaltung der Wirtschaftlichkeit neue Gedankenansaetze. Ein aus wirtschaftlicher und technischer Sicht reizvoller Optimierungsgedanke ist die untertaegige Wasser/Oel Separation, auch Downhole Dehydration genannt. Unter Downhole Dehydration (DHD) versteht man also die untertaegige (teilweise) Separation des Lagerstaettenwassers vom Nassoel, kurz nachdem das Gemisch untertaegig in das Bohrloch eingetreten ist. Dabei wird das abgetrennte Lagerstaettenwasser untertage in einen geeigneten Horizont unmittelbar wieder injiziert und das Oel (wie bei der konventionellen Foerderung) zutage gepumpt, mit dem Ziel der Nutzung der daraus resultierenden Kosten- und Investitionsersparnis. Ziel dieses Vortrages ist es, einen kurzen Einblick in die erstmalig in Europa angewandte Technik zu geben und von den Erfahrungen des praktizierten Feldversuches zu berichten. (orig.)

Regioselective desymmetrization of diaryltetrahydrofurans via directed ortho-lithiation: an unexpected help from green chemistry.

Science.gov (United States)

Mallardo, Valentina; Rizzi, Ruggiero; Sassone, Francesca C; Mansueto, Rosmara; Perna, Filippo M; Salomone, Antonio; Capriati, Vito

2014-08-14

An efficient functionalization of diaryltetrahydrofurans via a regioselective THF-directed ortho-lithiation is first described. This reaction can be successfully carried out in cyclopentyl methyl ether as a "greener" alternative to Et2O, with better results in terms of yield and selectivity and, surprisingly, also in protic eutectic mixtures competitively with protonolysis.

Structural analysis of isomeric chondroitin sulfate oligosaccharides using regioselective 6-O-desulfation method and tandem mass spectrometry.

Science.gov (United States)

Chen, Shu-Ting; Her, Guor-Rong

2014-09-16

A strategy based on a regioselective 6-O-desulfation reaction and negative ion electrospray ionization tandem mass spectrometry (ESI-MS(n)) was developed for the structural delineation of isomeric chondroitin sulfate oligosaccharides. Product ions resulting from the glycosidic cleavage provided information about the number of sulfate groups in each sugar residue. After the regioselective 6-O-desulfation reaction, the number of sulfate groups on each residue was obtained using a tandem mass spectrometry analysis of the reaction product. The sulfation pattern could be obtained based on the product ions of analytes before and after the desulfation reaction. The strategy was demonstrated using a series of tetrasaccharides prepared from shark cartilage chondroitin sulfate D. Among the 12 identified tetrasaccharides, six structures had not been reported before. Copyright © 2014 Elsevier B.V. All rights reserved.

Serum bicarbonate and dehydration severity in gastroenteritis

OpenAIRE

Narchi, H.

1998-01-01

The concentration of bicarbonate was measured in serum samples from 106 children with gastroenteritis and dehydration. A concentration less than 22 mmol/l was more common in children with severe dehydration, but the magnitude of bicarbonate reduction was not significantly different with increasing degrees of dehydration. Doctors should not rely on the serum bicarbonate concentration when assessing fluid deficit.



Relayed Regioselective Alkynylation/Olefination of Unsymmetrical Cyclic Diaryliodonium Species Catalyzed by Cu and Pd: Affording Fluorescent Cytotoxic Benzoxazoles.

Science.gov (United States)

Zhu, Daqian; Liu, Panpan; Lu, Wenhua; Wang, Haiwen; Luo, Bingling; Hu, Yumin; Huang, Peng; Wen, Shijun

2015-12-21

Although cyclic diaryliodonium species have the potential to act as valuable synthons for cascade transformations, they still remain largely unexplored. The regioselectivity associated with unsymmetrical cyclic diaryliodonium species has previously been known to pose a challenge. A regioselective relayed alkynylation and olefination of unsymmetrical cyclic diaryliodonium species has been achieved by installation of a directing amido group. These relayed transformations were delayed until an oxazole ring had formed, delivering a series of unique fluorescent benzoxazoles. Moreover, some of these synthetic benzoxazoles showed apparent inhibitory activity against malignant cancer cells. Further confocal visualization revealed that benzoxazoles targeted cell nuclei. These findings might provide a novel structural scaffold to develop desirable anticancer agents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Room temperature inorganic polycondensation of oxide (Cu2O and ZnO) nanoparticles and thin films preparation by the dip-coating technique

OpenAIRE

Salek, Guillaume; Tenailleau, Christophe; Dufour, Pascal; Guillemet-Fritsch, Sophie

2015-01-01

International audience; Oxide thin solid filmswere prepared by dip-coating into colloidal dispersions of oxide nanoparticles stabilized at room temperaturewithout the use of chelating or complex organic dispersing agents. Crystalline oxide nanoparticles were obtained by inorganic polycondensation and characterized by X-ray diffraction and field emission gun scanning electron microscopy. Water and ethanol synthesis and solution stabilization of oxide nanoparticle method was optimized to prepar...

Fructokinase activity mediates dehydration-induced renal injury.

Science.gov (United States)

Roncal Jimenez, Carlos A; Ishimoto, Takuji; Lanaspa, Miguel A; Rivard, Christopher J; Nakagawa, Takahiko; Ejaz, A Ahsan; Cicerchi, Christina; Inaba, Shinichiro; Le, MyPhuong; Miyazaki, Makoto; Glaser, Jason; Correa-Rotter, Ricardo; González, Marvin A; Aragón, Aurora; Wesseling, Catharina; Sánchez-Lozada, Laura G; Johnson, Richard J

2014-08-01

The epidemic of chronic kidney disease in Nicaragua (Mesoamerican nephropathy) has been linked with recurrent dehydration. Here we tested whether recurrent dehydration may cause renal injury by activation of the polyol pathway, resulting in the generation of endogenous fructose in the kidney that might subsequently induce renal injury via metabolism by fructokinase. Wild-type and fructokinase-deficient mice were subjected to recurrent heat-induced dehydration. One group of each genotype was provided water throughout the day and the other group was hydrated at night, after the dehydration. Both groups received the same total hydration in 24 h. Wild-type mice that received delayed hydration developed renal injury, with elevated serum creatinine, increased urinary NGAL, proximal tubular injury, and renal inflammation and fibrosis. This was associated with activation of the polyol pathway, with increased renal cortical sorbitol and fructose levels. Fructokinase-knockout mice with delayed hydration were protected from renal injury. Thus, recurrent dehydration can induce renal injury via a fructokinase-dependent mechanism, likely from the generation of endogenous fructose via the polyol pathway. Access to sufficient water during the dehydration period can protect mice from developing renal injury. These studies provide a potential mechanism for Mesoamerican nephropathy.

Ethanol dehydration on doped cadmium oxide

International Nuclear Information System (INIS)

Abd El-Salaam, K.M.

1975-01-01

The vapour phase catalytic dehydration of ethanol over Fe impregnated cadmium oxide was investigated between 200-450 0 C in atmospheric pressure. Electron transfer mechanisms involved in adsorption and catalytic dehydration reaction were investigated. The change in electrical conductivity of the catalyst resulting from calcination, adsorption and surface reaction processes were studied. Adsorption conductivity at low temperature ( 0 C) indicates that ethanol adsorbs as an electron donor. A mechanism of creation of interstitial Cd atoms responsible for the catalytic dehydration of ethanol on the catalyst surface was suggested. (orig.) [de

Electrolyte Concentrates Treat Dehydration

Science.gov (United States)

2009-01-01

Wellness Brands Inc. of Boulder, Colorado, exclusively licensed a unique electrolyte concentrate formula developed by Ames Research Center to treat and prevent dehydration in astronauts returning to Earth. Marketed as The Right Stuff, the company's NASA-derived formula is an ideal measure for athletes looking to combat dehydration and boost performance. Wellness Brands also plans to expand with products that make use of the formula's effective hydration properties to help treat conditions including heat stroke, altitude sickness, jet lag, and disease.

[Multicenter validation of the clinical dehydration scale for children].

Science.gov (United States)

Gravel, J; Manzano, S; Guimont, C; Lacroix, L; Gervaix, A; Bailey, B

2010-12-01

Dehydration is an important complication for sick children. The Clinical Dehydration Scale for children (CDS) measures dehydration based on 4 clinical signs: general appearance, eyes, saliva, and tears. To validate the association between the CDS and markers of dehydration in children aged 1 month to 5 years visiting emergency departments (EDs) for vomiting and/or diarrhea. An international prospective cohort study conducted in 3 university-affiliated EDs in 2009. Participants were a convenience sample of children aged 1-60 months presenting to the ED for acute vomiting and/or diarrhea. Following triage, a research nurse obtained informed consent and evaluated dehydration using the CDS. A few days after recovery, another research assistant weighed participants at home. The primary outcome was the percentage of dehydration calculated by the difference in weight at first evaluation and after recovery. Secondary outcomes included proportion of blood test measurements, intravenous use, hospitalization, and inter-rater agreement. During the study period, 264 children were recruited and data regarding weight and dehydration scores were complete for 219 (83%). According to the CDS, 88 had no dehydration, 159 some dehydration, and 15 moderate or severe dehydration. A Chi-square test showed a statistical association between CDS and weight gain, the occurrence of blood tests, intravenous rehydration, hospitalization, and abnormal plasmatic bicarbonate. Good inter-rater correlation was found among participants (linear weighted Kappa score of 0.65; (95% CI, 0.43-0.87). CDS categories correlate with markers of dehydration for young children complaining of vomiting and/or diarrhea in the ED. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Dehydration of aluminum chloride hexahydrate: a technical assessment

International Nuclear Information System (INIS)

Miller, R.L.

1984-04-01

Physical and chemical properties of aluminum chloride hexahydrate, ACH, and related compounds are noted as well as the relation of these properties to the problem of dehydration of ACH to form anhydrous aluminum chloride. Several approaches to the dehydration of ACH are discussed and a rationale or each approach is given: solvent extraction, ligand exchange, azeotropic distillation, chemical dehydration, and energy specific direct heating. While the thermodynamics of dehydration are frequently favorable, the rate of reaction and the mechanisms of reaction are more frequently unfavorable. However, each approach requires experimentation to test its effectiveness. The stability of the aluminum-oxygen bond in the hydrate is such that dehydration without decomposition to the oxide will be very difficult

Thermodynamics of mercaptopurine dehydration.

Science.gov (United States)

Niazi, S

1978-04-01

The hydrate form of mercaptopurine was shown to undergo peritectic decomposition of its water molecule, localized dissolution, and dehydration around 125 degrees. The anhydrate form was prepared by a thermal method, whose effectiveness was confirmed by X-ray diffraction, NMR spectroscopy, and differential scanning calorimetry. The activation energy for mercaptopurine dehydration calculated by various methods ranged from 45.74 to 63.04 kcal/mole. The dehydration enthalpy was calculated to be 8.27 kcal/mole by differential scanning calorimetry. The solution enthalpy for the hydrate was calculated to be 4.85 kcal/mole from its saturation solubility and differential scanning calorimetry. Anhydrate solubility in water was calculated based on initial dissolution rate data since the anhydrate converts to hydrate in aqueous media. The high degree of stability against interconversion of the hydrate and anhydrate forms and the higher solubility of the anhydrate suggest that use of the anhydrate might improve mercaptopurine bioavailability.

Overexpression of LOV KELCH protein 2 confers dehydration tolerance and is associated with enhanced expression of dehydration-inducible genes in Arabidopsis thaliana.

Science.gov (United States)

Miyazaki, Yuji; Abe, Hiroshi; Takase, Tomoyuki; Kobayashi, Masatomo; Kiyosue, Tomohiro

2015-05-01

The overexpression of LKP2 confers dehydration tolerance in Arabidopsis thaliana ; this is likely due to enhanced expression of dehydration-inducible genes and reduced stomatal opening. LOV KELCH protein 2 (LKP2) modulates the circadian rhythm and flowering time in plants. In this study, we observed that LKP2 overexpression enhanced dehydration tolerance in Arabidopsis. Microarray analysis demonstrated that expression of water deprivation-responsive genes was higher in the absence of dehydration stress in transgenic Arabidopsis plants expressing green fluorescent protein-tagged LKP2 (GFP-LKP2) than in control transgenic plants expressing GFP. After dehydration followed by rehydration, GFP-LKP2 plants developed more leaves and roots and exhibited higher survival rates than control plants. In the absence of dehydration stress, four dehydration-inducible genes, namely DREB1A, DREB1B, DREB1C, and RD29A, were expressed in GFP-LKP2 plants, whereas they were not expressed or were expressed at low levels in control plants. Under dehydration stress, the expression of DREB2B and RD29A peaked faster in the GFP-LKP2 plants than in control plants. The stomatal aperture of GFP-LKP2 plants was smaller than that of control plants. These results suggest that the dehydration tolerance of GFP-LKP2 plants is caused by upregulation of DREB1A-C/CBF1-3 and their downstream targets; restricted stomatal opening in the absence of dehydration stress also appears to contribute to the phenotype. The rapid and high expression of DREB2B and its downstream target genes also likely accounts for some features of the GFP-LKP2 phenotype. Our results suggest that LKP2 can be used for biotechnological applications not only to adjust the flowering time control but also to enhance dehydration tolerance.

Glassin, a histidine-rich protein from the siliceous skeletal system of the marine sponge Euplectella, directs silica polycondensation.

Science.gov (United States)

Shimizu, Katsuhiko; Amano, Taro; Bari, Md Rezaul; Weaver, James C; Arima, Jiro; Mori, Nobuhiro

2015-09-15

The hexactinellids are a diverse group of predominantly deep sea sponges that synthesize elaborate fibrous skeletal systems of amorphous hydrated silica. As a representative example, members of the genus Euplectella have proved to be useful model systems for investigating structure-function relationships in these hierarchically ordered siliceous network-like composites. Despite recent advances in understanding the mechanistic origins of damage tolerance in these complex skeletal systems, the details of their synthesis have remained largely unexplored. Here, we describe a previously unidentified protein, named "glassin," the main constituent in the water-soluble fraction of the demineralized skeletal elements of Euplectella. When combined with silicic acid solutions, glassin rapidly accelerates silica polycondensation over a pH range of 6-8. Glassin is characterized by high histidine content, and cDNA sequence analysis reveals that glassin shares no significant similarity with any other known proteins. The deduced amino acid sequence reveals that glassin consists of two similar histidine-rich domains and a connecting domain. Each of the histidine-rich domains is composed of three segments: an amino-terminal histidine and aspartic acid-rich sequence, a proline-rich sequence in the middle, and a histidine and threonine-rich sequence at the carboxyl terminus. Histidine always forms HX or HHX repeats, in which most of X positions are occupied by glycine, aspartic acid, or threonine. Recombinant glassin reproduces the silica precipitation activity observed in the native proteins. The highly modular composition of glassin, composed of imidazole, acidic, and hydroxyl residues, favors silica polycondensation and provides insights into the molecular mechanisms of skeletal formation in hexactinellid sponges.

Dehydration related abdominal pain (drap)

International Nuclear Information System (INIS)

Shah, S.I.; Aurangzeb; Khan, I.; Bhatti, A.M.; Khan, A.A.

2004-01-01

Objective: To describe the frequency of dehydration as a medical cause of acute abdomen. Subjects and Methods: All the patients reporting with abdominal pain to the surgical outpatient department or the emergency department were reviewed in the study. The clinical findings in all these cases were studied along with the mode of their management and outcome. Results: Of all the patients presenting with abdominal pain, 3.3% (n=68) were suffering from dehydration related abdominal pain. They were predominantly males in a ratio of 8.7: 1, mostly in the 2nd and 3rd decades of their lives. All these cases were suffering from acute or chronic dehydration were provisionally diagnosed by general practitioners as 'acute abdomen' and referred for surgical consultation. Associated symptoms included vomiting in 42.6%, backache in 91.2%, headache in 95.6%, and pain in lower limbs in 97.1 % of the cases. 83.8% required indoor management with intravenous fluids. All the patients became asymptomatic with rehydration therapy. Conclusion: Dehydration is a possible cause of severe abdominal pain. There is a need to educate the general public about the benefits of adequate fluid intake. (author)

Regioselective Palmitoylation of 9-(2,3-Dihydroxy-propyl)adenine Catalyzed by a Glycopolymer-enzyme Conjugate

Czech Academy of Sciences Publication Activity Database

Brabcová, Jana; Blažek, Jiří; Krečmerová, Marcela; Vondrášek, Jiří; Palomo, J. M.; Zarevúcka, Marie

2016-01-01

Roč. 21, č. 5 (2016), č. článku 648. ISSN 1420-3049 Grant - others:AV ČR(CZ) M200551203 Institutional support: RVO:61388963 Keywords : regioselectivity * palmitoylation * glycosylation * chemical modification Subject RIV: CE - Biochemistry Impact factor: 2.861, year: 2016 http://www.mdpi.com/1420-3049/21/5/648/htm

Irradiation of dehydrated vegetables

International Nuclear Information System (INIS)

Esterhuyse, A; Esterhuizen, T.

1985-01-01

The reason for radurization was to decreased the microbial count of dehydrated vegetables. The average absorbed irradiation dose range between 2kGy and 15kGy. The product catagories include a) Green vegetables b) White vegetables c) Powders of a) and b). The microbiological aspects were: Declining curves for the different products of T.P.C., Coliforms, E. Coli, Stap. areus, Yeast + Mold at different doses. The organoleptical aspects were: change in taste, flavour, texture, colour and moisture. The aim is the marketing of irradiated dehydrated vegetables national and international basis

Synthesis of unnatural amino acids via microwave-assisted regio-selective one-pot multi-component reactions of sulfamidates

Science.gov (United States)

Synthesis of triazole-based unnatural amino acids, triazole bisaminoacids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW irradiation conditions. The developed method is app...

A facile and regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles using click chemistry

Science.gov (United States)

The reaction of α-tosyloxy ketones, sodium azide and terminal alkynes in presence of copper(I) in aqueous polyethylene glycol afforded regioselectively 1,4-disubstituted 1,2,3-triazoles in good yield at ambient temperature. The one-pot exclusive formation of 1,4-disubstituted 1,2...

Hypertension despite dehydration during severe pediatric diabetic ketoacidosis.

Science.gov (United States)

Deeter, Kristina H; Roberts, Joan S; Bradford, Heidi; Richards, Todd; Shaw, Dennis; Marro, Kenneth; Chiu, Harvey; Pihoker, Catherine; Lynn, Anne; Vavilala, Monica S

2011-06-01

Diabetic ketoacidosis (DKA) may result in both dehydration and cerebral edema but these processes may have opposing effects on blood pressure. We examined the relationship between dehydration and blood pressure in pediatric DKA. A retrospective review was performed at Seattle Children's Hospital, Seattle, WA. Participants were hospitalized children less than 18 yr. Intervention(s) or main exposure was to patients with DKA (venous pH 300 mg/dL, HCO(3) Dehydration was calculated as percent body weight lost at admission compared to discharge. Hypertension (systolic and/or diastolic blood pressure (DBP) percentile > 95%) was defined based on National Heart, Lung, and Blood Institute (NHLBI, 2004) nomograms and hypotension was defined as systolic blood pressure (SBP) dehydration. Despite dehydration, most children admitted with severe DKA had hypertension. © 2011 John Wiley & Sons A/S.

Regioselective Alcoholysis of Silychristin Acetates Catalyzed by Lipases ‡

Science.gov (United States)

Vavříková, Eva; Gavezzotti, Paolo; Purchartová, Kateřina; Fuksová, Kateřina; Biedermann, David; Kuzma, Marek; Riva, Sergio; Křen, Vladimír

2015-01-01

A panel of lipases was screened for the selective acetylation and alcoholysis of silychristin and silychristin peracetate, respectively. Acetylation at primary alcoholic group (C-22) of silychristin was accomplished by lipase PS (Pseudomonas cepacia) immobilized on diatomite using vinyl acetate as an acetyl donor, whereas selective deacetylation of 22-O-acetyl silychristin was accomplished by Novozym 435 in methyl tert-butyl ether/n-butanol. Both of these reactions occurred without diastereomeric discrimination of silychristin A and B. Both of these enzymes were found to be capable to regioselective deacetylation of hexaacetyl silychristin to afford penta-, tetra- and tri-acetyl derivatives, which could be obtained as pure synthons for further selective modifications of the parent molecule. PMID:26016503

Regioselective Wacker Oxidation of Internal Alkenes: Rapid Access to Functionalized Ketones Facilitated by Cross-Metathesis

KAUST Repository

Morandi, Bill

2013-07-26

Wacka wacka: The title reaction makes use of a wide range of directing groups (DG) to enable the highly regioselective oxidation of alkenes, and occurs predictably at the distal position. Both E and Z alkenes afford valuable functionalized ketones and cross-metathesis was shown to facilitate the preparation of the starting materials. BQ=benzoquinone.

Regioselective Wacker Oxidation of Internal Alkenes: Rapid Access to Functionalized Ketones Facilitated by Cross-Metathesis

KAUST Repository

Morandi, Bill; Wickens, Zachary K.; Grubbs, Robert H.

2013-01-01

Wacka wacka: The title reaction makes use of a wide range of directing groups (DG) to enable the highly regioselective oxidation of alkenes, and occurs predictably at the distal position. Both E and Z alkenes afford valuable functionalized ketones and cross-metathesis was shown to facilitate the preparation of the starting materials. BQ=benzoquinone.

Stereo- and regio-selective one-pot synthesis of triazole-based unnatural amino acids and β- amino triazoles

Science.gov (United States)

Synthesis of triazole based unnatural amino acids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW conditions. The developed method is applicable to a broad substrate scope a...

Microglassification™: a Novel Technique for Protein Dehydration

DEFF Research Database (Denmark)

Aniket; Gaul, David; Rickard, Deborah

2014-01-01

he dehydration of biologics is commonly employed to achieve solid-dose formulation and enhanced stability during long-term preservation. We have developed a novel process, MicroglassificationTM, which can rapidly and controllably dehydrate protein solutions into solid amorphous microspheres at room...... time and decreasing water activity. Image analysis at single particle and bulk scale showed the formation of solid BSA microspheres with a maximum protein concentration of 1147 ± 32 mg/mL. The native BSA samples were dehydrated to approximately 450 waters per BSA, which is well below monolayer coverage...... of 1282 waters per BSA. The secondary structure of MicroglassifiedTM BSA reverted to native-like conformation upon rehydration with only minor irreversible aggregation (2.7%). Results of the study establish the efficacy of the MicroglassificationTM for the successful dehydration of biologics....

Dehydration of core/shell fruits

OpenAIRE

Liu, Y.; Yang, Xiaosong; Cao, Y.; Wang, Z.; Chen, B.; Zhang, Jian J.; Zhang, H.

2015-01-01

Dehydrated core/shell fruits, such as jujubes, raisins and plums, show very complex buckles and wrinkles on their exocarp. It is a challenging task to model such complicated patterns and their evolution in a virtual environment even for professional animators. This paper presents a unified physically-based approach to simulate the morphological transformation for the core/shell fruits in the dehydration process. A finite element method (FEM), which is based on the multiplicative decomposition...

Regioselective Rh-Catalyzed Hydroformylation of 1,1,3-Trisubstituted Allenes Using BisDiazaPhos Ligand.

Science.gov (United States)

Eshon, Josephine; Landis, Clark R; Schomaker, Jennifer M

2017-09-15

The efficient hydroformylation of 1,1,3-trisubstituted allenes is accomplished with low loadings of a Rh catalyst supported by a BisDiazaPhos (BDP) ligand. The ligand identity is key to achieving high regioselectivity, while the mild reaction conditions minimize competing isomerization and hydrogenation to produce β,γ-unsaturated aldehydes and their derivatives in excellent yields.

Remote control of regioselectivity in acyl-acyl carrier protein-desaturases.

Science.gov (United States)

Guy, Jodie E; Whittle, Edward; Moche, Martin; Lengqvist, Johan; Lindqvist, Ylva; Shanklin, John

2011-10-04

Regiospecific desaturation of long-chain saturated fatty acids has been described as approaching the limits of the discriminatory power of enzymes because the substrate entirely lacks distinguishing features close to the site of dehydrogenation. To identify the elusive mechanism underlying regioselectivity, we have determined two crystal structures of the archetypal Δ9 desaturase from castor in complex with acyl carrier protein (ACP), which show the bound ACP ideally situated to position C9 and C10 of the acyl chain adjacent to the diiron active site for Δ9 desaturation. Analysis of the structures and modeling of the complex between the highly homologous ivy Δ4 desaturase and ACP, identified a residue located at the entrance to the binding cavity, Asp280 in the castor desaturase (Lys275 in the ivy desaturase), which is strictly conserved within Δ9 and Δ4 enzymes but differs between them. We hypothesized that interaction between Lys275 and the phosphate of the pantetheine, seen in the ivy model, is key to positioning C4 and C5 adjacent to the diiron center for Δ4 desaturation. Mutating castor Asp280 to Lys resulted in a major shift from Δ9 to Δ4 desaturation. Thus, interaction between desaturase side-chain 280 and phospho-serine 38 of ACP, approximately 27 Å from the site of double-bond formation, predisposes ACP binding that favors either Δ9 or Δ4 desaturation via repulsion (acidic side chain) or attraction (positively charged side chain), respectively. Understanding the mechanism underlying remote control of regioselectivity provides the foundation for reengineering desaturase enzymes to create designer chemical feedstocks that would provide alternatives to those currently obtained from petrochemicals.

Observations on saliva osmolality during progressive dehydration and partial rehydration.

Science.gov (United States)

Taylor, Nigel A S; van den Heuvel, Anne M J; Kerry, Pete; McGhee, Sheena; Peoples, Gregory E; Brown, Marc A; Patterson, Mark J

2012-09-01

A need exists to identify dehydrated individuals under stressful settings beyond the laboratory. A predictive index based on changes in saliva osmolality has been proposed, and its efficacy and sensitivity was appraised across mass (water) losses from 1 to 7%. Twelve euhydrated males [serum osmolality: 286.1 mOsm kg(-1) H(2)O (SD 4.3)] completed three exercise- and heat-induced dehydration trials (35.6°C, 56% relative humidity): 7% dehydration (6.15 h), 3% dehydration (with 60% fluid replacement: 2.37 h), repeat 7% dehydration (5.27 h). Expectorated saliva osmolality, measured at baseline and at each 1% mass change, was used to predict instantaneous hydration state relative to mass losses of 3 and 6%. Saliva osmolality increased linearly with dehydration, although its basal osmolality and its rate of change varied among and within subjects across trials. Receiver operating characteristic curves indicated a good predictive power for saliva osmolality when used with two, single-threshold cutoffs to differentiate between hydrated and dehydrated individuals (area under curve: 3% cutoff = 0.868, 6% cutoff = 0.831). However, when analysed using a double-threshold detection technique (3 and 6%), as might be used in a field-based monitor, <50% of the osmolality data could correctly identify individuals who exceeded 3% dehydration. Indeed, within the 3-6% dehydration range, its sensitivity was 64%, while beyond 6% dehydration, this fell to 42%. Therefore, while expectorated saliva osmolality tracked mass losses within individuals, its large intra- and inter-individual variability limited its predictive power and sensitivity, rendering its utility questionable within a universal dehydration monitor.

Dehydration in children with diabetic ketoacidosis: a prospective study.

Science.gov (United States)

Sottosanti, Maria; Morrison, Gavin C; Singh, Ram N; Sharma, Ajay P; Fraser, Douglas D; Alawi, Khalid; Seabrook, Jamie A; Kornecki, Alik

2012-02-01

To investigate the association between the degree of patient dehydration on presentation with diabetic ketoacidosis (DKA) and clinical and laboratory parameters obtained on admission. Prospective descriptive study. A tertiary care children's hospital. Thirty-nine paediatric patients (1 month-16 years) presenting with 42 episodes of DKA. Clinical and biochemical variables were collected on admission. Dehydration was calculated by measuring acute changes in body weight during the period of illness. All patients were treated according to a previously established protocol. Magnitude of dehydration, defined as % loss of body weight (LBW), was determined by the difference in body weight obtained at presentation and at discharge. The relationship between the magnitude of dehydration and the clinical assessment and biochemical parameters was examined. The median (25th-75th centiles) magnitude of dehydration at presentation was 5.7% (3.8-8.3%) (mean ± SD 6.8 ± 5%). Neither the initial clinical assessment nor the comprehensive biochemical profile at admission correlated with the magnitude of dehydration. Despite considerable variation in the degree of dehydration and biochemical disequilibrium, all patients recovered from DKA within 24 h with a standardised therapeutic approach. Furthermore, the rapidity of patient recovery did not correlate with the magnitude of dehydration on presentation or the amount of fluid administered (median (25th-75th centiles) 48.8 ml/kg (38.5-60.3)) in the first 12 h. The magnitude of dehydration in DKA is not reflected by either clinical or biochemical parameters. These findings need confirmation in larger studies.

Freeze dehydration of milk using microwave energy

International Nuclear Information System (INIS)

Souda, K.B.; Akyel, C.; Bilgen, E.

1989-01-01

This paper presents the results of experimental studies on heat and mass transfer during a microwave freeze dehydration process. An experimental system and procedure was developed to freeze dry milk. A 2500-W microwave system with an appropriate wave guide was set up and instrumented, and a procedure was experimentally developed to obtain milk powder first by freezing milk and then dehydrating it at low pressure using microwave energy. An unsteady-state analysis was used to derive a one-dimensional mathematical model of the freeze dehydration process in a microwave electromagnetic field

Research Update: A hafnium-based metal-organic framework as a catalyst for regioselective ring-opening of epoxides with a mild hydride source

International Nuclear Information System (INIS)

Stephenson, Casey J.; Hassan Beyzavi, M.; Klet, Rachel C.; Hupp, Joseph T.; Farha, Omar K.

2014-01-01

Reaction of styrene oxide with sodium cyanoborohydride and a catalytic amount of Hf-NU-1000 yields the anti-Markovnikov product, 2-phenylethanol, with over 98% regioselectivity. On the other hand, propylene oxide is ring opened in a Markovnikov fashion to form 2-propanol with 95% regioselectivity. Both styrene oxide and propylene oxide failed to react with sodium cyanoborohydride without the addition of Hf-NU-1000 indicative of the crucial role of Hf-NU-1000 as a catalyst in this reaction. To the best of our knowledge, this is the first report of the use of a metal-organic framework material as a catalyst for ring-opening of epoxides with hydrides

Computational Dehydration of Crystalline Hydrates Using Molecular Dynamics Simulations

DEFF Research Database (Denmark)

Larsen, Anders Støttrup; Rantanen, Jukka; Johansson, Kristoffer E

2017-01-01

Molecular dynamics (MD) simulations have evolved to an increasingly reliable and accessible technique and are today implemented in many areas of biomedical sciences. We present a generally applicable method to study dehydration of hydrates based on MD simulations and apply this approach...... to the dehydration of ampicillin trihydrate. The crystallographic unit cell of the trihydrate is used to construct the simulation cell containing 216 ampicillin and 648 water molecules. This system is dehydrated by removing water molecules during a 2200 ps simulation, and depending on the computational dehydration....... The structural changes could be followed in real time, and in addition, an intermediate amorphous phase was identified. The computationally identified dehydrated structure (anhydrate) was slightly different from the experimentally known anhydrate structure suggesting that the simulated computational structure...

A study on dehydration of rare earth chloride hydrate

International Nuclear Information System (INIS)

Cho, Yong Zun; Eun, Hee Chul; Son, Sung Mo; Lee, Tae Kyo; Hwang, Taek Sung

2012-01-01

The dehydration schemes of rare earth (La, Ce, Nd, Pr, Sm. Eu, Gd, Y) chloride hydrates was investigated by using a dehydration apparatus. To prevent the formation of the rare earth oxychlorides, the operation temperature was changed step by step (80→150→230 degree C) based on the TGA (thermo-gravimetric analysis) results of the rare earth chloride hydrates. A vacuum pump and preheated Ar gas were used to effectively remove the evaporated moisture and maintain an inert condition in the dehydration apparatus. The dehydration temperature of the rare earth chloride hydrate was increased when the atomic number of the rare earth nuclide was increased. The content of the moisture in the rare earth chloride hydrate was decreased below 10% in the dehydration apparatus.

Retention of nutrients in green leafy vegetables on dehydration.

Science.gov (United States)

Gupta, Sheetal; Gowri, B S; Lakshmi, A Jyothi; Prakash, Jamuna

2013-10-01

The objective of the study was to investigate the influence of dehydration on nutrient composition of Amaranthus gangeticus, Chenopodium album, Centella asiatica, Amaranthus tricolor and Trigonella foenum graecum. The green leafy vegetables (GLV) were steam blanched for 5 min after pretreatment and dried in an oven at 60 °C for 10-12 h. The fresh and dehydrated samples were analyzed for selected proximate constituents, vitamins, minerals, antinutrients and dialyzable minerals. Dehydration seems to have little effect on the proximate, mineral and antinutrient content of the GLV. Among the vitamins, retention of ascorbic acid was 1-14%, thiamine 22-71%, total carotene 49-73% and β-carotene 20-69% respectively, of their initial content. Dialyzable iron and calcium in the fresh vegetables ranged between 0.21-3.5 mg and 15.36-81.33 mg/100 g respectively, which reduced to 0.05-0.53 mg and 6.94-58.15 mg/100 g on dehydration. Dehydration seems to be the simplest convenient technology for preserving these sources of micronutrients, especially when they are abundantly available. Irrespective of the losses of vitamins that take place during dehydration, dehydrated GLV are a concentrated natural source of micronutrients and they can be used in product formulations. Value addition of traditional products with dehydrated GLV can be advocated as a feasible food-based approach to combat micronutrient malnutrition.

A Mild and Green Route for Regio-selective Amination of Oxiranes Using Nanomagnetic Supported Ferrous Ion as a Solid Lewis Acid Catalyst in Water

Directory of Open Access Journals (Sweden)

Fariborz Mansouri

2016-07-01

Full Text Available A mild, green and highly efficient route for regio-selective amination of oxiranes was developed via incorporation of Mn(II, Fe(II, Co(II, Ni(II, Cu(II and Zn(II cations onto the surface of hydroxyapatite-encapsulated γ-Fe2O3 nanoparticles (γ-Fe2O3@HAp. Among six magnetically recoverable catalytic systems denoted as [γ-Fe2O3@HAp-MII], the catalyst in which M designated as Fe(II showed the best efficiency as well as regio-selectivity in amination of oxiranes under an ambient reaction condition. A wide variety of aromatic and aliphatic amines were reacted with epoxides using magnetically separable iron catalyst to give the corresponding amino alcohols in excellent yields and selectivities in water as solvent at room temperature. In addition, recovery of the catalyst was successfully carried out in subsequent runs without any decrease in activity even after 5 runs. High regio-selectivity toward terminal ring-opening, efficient catalyst reusability using simple magnetic separation, high yields, simplicity in operation and diversity for various substrates are of advantages of this study.

Mechanistic Basis for Regioselection and Regiodivergence in Nickel-Catalyzed Reductive Couplings

Science.gov (United States)

Jackson, Evan P.; Malik, Hasnain A.; Sormunen, Grant J.; Baxter, Ryan D.; Liu, Peng; Wang, Hengbin; Shareef, Abdur-Rafay; Montgomery, John

2015-01-01

CONSPECTUS The control of regiochemistry is a considerable challenge in the development of a wide array of catalytic processes. Simple π-components such as alkenes, alkynes, 1,3-dienes, and allenes are among the many classes of substrates that present complexities in regioselective catalysis. Considering an internal alkyne as a representative example, when steric and electronic differences between the two substituents are minimal, differentiating among the two termini of the alkyne presents a great challenge. In cases where the differences between the alkyne substituents are substantial, overcoming those biases to access the regioisomer opposite that favored by substrate biases often presents an even greater challenge. Nickel-catalyzed reductive couplings of unsymmetrical π-components make up a group of reactions where control of regiochemistry presents a challenging but important objective. In the course of our studies of aldehyde-alkyne reductive couplings, complementary solutions to challenges in regiocontrol have been developed. Through careful selection of the ligand and reductant, as well as the more subtle reaction variables such as temperature and concentration, effective protocols have been established that allow highly selective access to either regiosiomer of the the allylic alcohol products using a wide range of unsymmetrical alkynes. Computational studies and an evaluation of reaction kinetics have provided an understanding of the origin of the regioselectivity control. Throughout the various procedures described, the development of ligand-substrate interactions play a key role, and the overall kinetic descriptions were found to differ between protocols. Rational alteration of the rate-determining step plays a key role in the regiochemistry reversal strategy, and in one instance, the two possible regioisomeric outcomes in a single reaction were found to operate by different kinetic descriptions. With this mechanistic information in hand, the

Regioselective 1,4-trifluoromethylation of α,β-unsaturated ketones via a S-(trifluoromethyldiphenylsulfonium salts/copper system

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Satoshi Okusu

2013-10-01

Full Text Available Regioselective conjugate 1,4-trifluoromethylation of α,β-unsaturated ketones by the use of shelf-stable electrophilic trifluoromethylating reagents, S-(trifluoromethyldiphenylsulfonium salts and copper under mild conditions is described. A wide range of acyclic aryl–aryl–enones and aryl–alkyl–enones were converted into β-trifluoromethylated ketones in low to moderate yields.

The synthesis of amphipathic prodrugs of 1,2-diol drugs with saccharide conjugates by high regioselective enzymatic protocol.

Science.gov (United States)

Quan, Jing; Chen, Zhichun; Han, Chengyou; Lin, Xianfu

2007-02-15

A facile, high regioselective enzymatic synthesis approach for the preparation of amphipathic prodrugs with saccharides of mephenesin and chlorphenesin was developed. Firstly, transesterification of two drugs with divinyl dicarboxylates with different carbon chain length was performed under the catalysis of Candida antarctica lipase acrylic resin and Lipozyme in anhydrous acetone at 50 degrees C, respectively. A series of lipophilic derivatives with vinyl groups of mephenesin and chlorphenesin were prepared. The influences of different organic solvents, enzyme sources, reaction time, and the acylation reagents on the synthesis of vinyl esters were investigated. And then, protease-catalyzed high regioselective acylation of D-glucose and D-mannose with vinyl esters of mephenesin and chlorphenesin gave drug-saccharide derivatives in good yields. The studies of lipophilicity and hydrolysis in vitro of prodrugs verified that drug-saccharide derivatives had amphipathic properties, and both lipophilic and amphipathic drug derivatives had obvious controlled release characteristics.

Diagnosing dehydration? Blend evidence with clinical observations.

Science.gov (United States)

Armstrong, Lawrence E; Kavouras, Stavros A; Walsh, Neil P; Roberts, William O

2016-11-01

The purpose of the review is to provide recommendations to improve clinical decision-making based on the strengths and weaknesses of commonly used hydration biomarkers and clinical assessment methods. There is widespread consensus regarding treatment, but not the diagnosis of dehydration. Even though it is generally accepted that a proper clinical diagnosis of dehydration can only be made biochemically rather than relying upon clinical signs and symptoms, no gold standard biochemical hydration index exists. Other than clinical biomarkers in blood (i.e., osmolality and blood urea nitrogen/creatinine) and in urine (i.e., osmolality and specific gravity), blood pressure assessment and clinical symptoms in the eye (i.e., tear production and palpitating pressure) and the mouth (i.e., thirst and mucous wetness) can provide important information for diagnosing dehydration. We conclude that clinical observations based on a combination of history, physical examination, laboratory values, and clinician experience remain the best approach to the diagnosis of dehydration.

Water-activity of dehydrated guava slices sweeteners

International Nuclear Information System (INIS)

Ayub, M.; Zeb, A.; Ullah, J.

2005-01-01

A study was carried out to investigate the individual and combined effect of caloric sweeteners (sucrose, glucose and fructose) and non-caloric sweeteners (saccharine, cyclamate and aspartame) along with antioxidants (citric acid and ascorbic acid) and chemical preservatives (potassium metabisulphite and potassium sorbate) on the water-activity (a/sub w/) of dehydrated guava slices. Different dilutions of caloric sweeteners (20, 30, 40 and 50 degree brix (bx) and non-caloric sweeteners (equivalent to sucrose sweetness) were used. Guava slices were osmotically dehydrated in these solutions and then dehydrated initially at 0 and then at 60 degree C to final moisture-content of 20-25%. Guava slices prepared with sucrose: glucose 7:3 potassium metabisulphite, ascorbic acid and citric acid produced best quality products, which have minimum (a/sub w/) and best overall sensory characteristics. The analysis showed that treatments and their various concentrations had a significant effect (p=0.05) on (a/sub w/) of dehydrated guava slices. (author)

Comparison of gas dehydration methods based on energy ...

African Journals Online (AJOL)

Comparison of gas dehydration methods based on energy consumption. ... PROMOTING ACCESS TO AFRICAN RESEARCH ... This study compares three conventional methods of natural gas (Associated Natural Gas) dehydration to carry out ...

Effects of Dehydration on Brain Functioning: A Life-Span Perspective.

Science.gov (United States)

Pross, Nathalie

2017-01-01

In the last 10 years, there has been an increase in the publication of literature dealing with the effects of mild dehydration on cognition in healthy adults. Fewer studies, leading to less consistent data, involved other age groups. In healthy young adults refraining from drinking or participating in dehydration protocols, it was found that mild dehydration had no impact on performance, whereas the mood was widely impaired. Several studies have also been conducted in young children either as observational studies or as interventional studies. Nevertheless, methodological differences in (de)hydration monitoring, in cognitive assessments, and in the age/brain maturation of study participants, often resulted in contradictory findings regarding the cognitive functions impacted by (de)hydration. Although not consistent, these data showed that not only mood but also performance tend to be impaired by dehydration in children. Even if older adults are likely to be more vulnerable to dehydration than younger adults, very few studies have been conducted in this regard in this population. The results show that, like it is in children, cognition tends to be impaired when the elderly are dehydrated. Taken together, these studies suggest that dehydration has greater detrimental effects in vulnerable populations. Recent imaging data suggest that the brain of children and elderly adults may have fewer resources to manage the effects of dehydration. Consequently, cognitive tasks may be more demanding for younger and older brains and performance more likely to be impaired in these populations, in comparison to young healthy subjects who have greater and more efficient resources. © 2017 The Author(s) Published by S. Karger AG, Basel.

Using Dehydrated Vegetables in Some Brown Bread Types

Directory of Open Access Journals (Sweden)

Simona Man

2013-11-01

Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 Expanding the range of bakery products in terms of producing supplemented or dietetic products has been an increasingly important trend in contemporary baking. Bakery products as basic and popular food, could be used in the prevention of nutritive deficiencies of many important nutrients, by supplementing the products with biologically valuable ingredients. Such ingredients are dehydrated vegetables in the form of powder. For establishing the bread quality, a special importance shows it’s chemical composition, because the substances that enter in it’s constitution serve to obtaining the energy necessary to the human body. Beside the chemical composition, the bread quality and alimentary use, respectively, depends a large measure on a series of signs: flavor and taste, external appearance, crumb porosity and texture, breads’ volume. This paper belongs to a more complex study, which aims are obtaining some bread assortments with high nutritional value, and improving their sensorial and rheological features, by adding dehydrated vegetables at different levels 4% potato flakes, 2% dehydrated onion, 0.5% dehydrated garlic and 2% dehydrated leek.

Effects of Dehydration on Fish Muscles at Chilled Temperature

Science.gov (United States)

Miki, Hidemasa; Seto, Fuminori; Nishimoto, Motomi; Nishimoto, Junichi

Recently,new method of removing water from fish fillet at low temperature using dehydration sheet have been reported. The present study is concerned with the factors to affect the quality during dehydration of horse mackerel muscle at low temperature. The rate of dehydration at -3 °C was about two times faster than that at 0 °C. The rate of denaturation of fish muscle protein was kept less than about 10 % (ATPase activity) of the undenaturated initial values after removing free water content. Present results suggest the practical possibility of the dehydration at -3 °C for keeping quality of fish flesh.

Uric acid and dehydration in children with gastroenteritis.

Science.gov (United States)

Kuge, Rie; Morikawa, Yoshihiko; Hasegawa, Yukihiro

2017-11-01

Clinical assessment of dehydration in children with acute gastroenteritis (AGE) is crucial for treatment. The gold standard for assessment is acute weight loss. Dehydration severity, as determined by weight loss, significantly correlates with serum urea nitrogen (UN) in children with AGE. The disadvantage of using serum UN as a marker of dehydration severity, however, is that the level can be affected by nutrition. Serum uric acid (UA) theoretically could serve as an alternative in this regard, but there have been no reports on the direct relationship between serum UA and weight loss. The aim of this study was therefore to assess the relationship between serum UA and weight loss in patients with AGE. This was a prospective observational study of children 1-71 months of age admitted to Tokyo Metropolitan Children's Medical Center with AGE between 1 December 2010 and 31 March 2015. Patients with symptoms of AGE ≥ 8 days, chronic disease, or incomplete data were excluded from the study. Pre-post-rehydration weight change was used as an alternative, gold standard marker for the assessment of dehydration severity. The study participants consisted of 97 children. Serum UA correlated significantly with weight change, and increased significantly along with dehydration severity. Serum UA can be considered as an adjunct to the clinical assessment of dehydration in children with AGE. © 2017 Japan Pediatric Society.

Whole transcriptome organisation in the dehydrated supraoptic nucleus

Directory of Open Access Journals (Sweden)

C.C.T. Hindmarch

2013-12-01

Full Text Available The supraoptic nucleus (SON is part of the central osmotic circuitry that synthesises the hormone vasopressin (Avp and transports it to terminals in the posterior lobe of the pituitary. Following osmotic stress such as dehydration, this tissue undergoes morphological, electrical and transcriptional changes to facilitate the appropriate regulation and release of Avp into the circulation where it conserves water at the level of the kidney. Here, the organisation of the whole transcriptome following dehydration is modelled to fit Zipf's law, a natural power law that holds true for all natural languages, that states if the frequency of word usage is plotted against its rank, then the log linear regression of this is -1. We have applied this model to our previously published euhydrated and dehydrated SON data to observe this trend and how it changes following dehydration. In accordance with other studies, our whole transcriptome data fit well with this model in the euhydrated SON microarrays, but interestingly, fit better in the dehydrated arrays. This trend was observed in a subset of differentially regulated genes and also following network reconstruction using a third-party database that mines public data. We make use of language as a metaphor that helps us philosophise about the role of the whole transcriptome in providing a suitable environment for the delivery of Avp following a survival threat like dehydration.

Fruits and vegetables dehydration

International Nuclear Information System (INIS)

De Ita, A; Flores, G; Franco, F

2015-01-01

Dehydration diagrams were determined by means of Differential Thermal Analysis, DTA, and Thermo Gravimetric Analysis, TGA, curves of several simultaneous fruits and vegetables, all under the same conditions. The greater mass loss is associated with water containing in the structure of the investigated materials at low temperature. In poblano chile water is lost in a single step. The banana shows a very sharply two stages, while jicama can be observed although with a little difficulty three stages. The major mass loss occurs in the poblano chile and the lower in banana. The velocity and temperature of dehydration vary within a small range for most materials investigated, except for banana and cactus how are very different

Fruits and vegetables dehydration

Science.gov (United States)

de Ita, A.; Flores, G.; Franco, F.

2015-01-01

Dehydration diagrams were determined by means of Differential Thermal Analysis, DTA, and Thermo Gravimetric Analysis, TGA, curves of several simultaneous fruits and vegetables, all under the same conditions. The greater mass loss is associated with water containing in the structure of the investigated materials at low temperature. In poblano chile water is lost in a single step. The banana shows a very sharply two stages, while jicama can be observed although with a little difficulty three stages. The major mass loss occurs in the poblano chile and the lower in banana. The velocity and temperature of dehydration vary within a small range for most materials investigated, except for banana and cactus how are very different.

Immobilisation increases yeast cells' resistance to dehydration-rehydration treatment.

Science.gov (United States)

Borovikova, Diana; Rozenfelde, Linda; Pavlovska, Ilona; Rapoport, Alexander

2014-08-20

This study was performed with the goal of revealing if the dehydration procedure used in our new immobilisation method noticeably decreases the viability of yeast cells in immobilised preparations. Various yeasts were used in this research: Saccharomyces cerevisiae cells that were rather sensitive to dehydration and had been aerobically grown in an ethanol-containing medium, a recombinant strain of S. cerevisiae grown in aerobic conditions which were completely non-resistant to dehydration and an anaerobically grown bakers' yeast strain S. cerevisiae, as well as a fairly resistant Pichia pastoris strain. Experiments performed showed that immobilisation of all these strains essentially increased their resistance to a dehydration-rehydration treatment. The increase of cells' viability (compared with control cells dehydrated in similar conditions) was from 30 to 60%. It is concluded that a new immobilisation method, which includes a dehydration stage, does not lead to an essential loss of yeast cell viability. Correspondingly, there is no risk of losing the biotechnological activities of immobilised preparations. The possibility of producing dry, active yeast preparations is shown, for those strains that are very sensitive to dehydration and which can be used in biotechnology in an immobilised form. Finally, the immobilisation approach can be used for the development of efficient methods for the storage of recombinant yeast strains. Copyright © 2014 Elsevier B.V. All rights reserved.

Diagnosis and management of dehydration in children.

Science.gov (United States)

Canavan, Amy; Arant, Billy S

2009-10-01

The most useful individual signs for identifying dehydration in children are prolonged capillary refill time, abnormal skin turgor, and abnormal respiratory pattern. However, clinical dehydration scales based on a combination of physical examination findings are better predictors than individual signs. Oral rehydration therapy is the preferred treatment of mild to moderate dehydration caused by diarrhea in children. Appropriate oral rehydration therapy is as effective as intravenous fluid in managing fluid and electrolyte losses and has many advantages. Goals of oral rehydration therapy are restoration of circulating blood volume, restoration of interstitial fluid volume, and maintenance of rehydration. When rehydration is achieved, a normal age-appropriate diet should be initiated.

A facile regioselective synthesis of novel spiroacenaphthene pyrroloisoquinolines through 1,3-dipolar cycloaddition reactions

International Nuclear Information System (INIS)

Sarrafi, Yaghoub; Asghari, Asieh; Sadatshahabi, Marzieh; Hamzehloueian, Mahshid; Alimohammadi, Kamal

2013-01-01

An efficient one-pot three-component procedure for the synthesis of novel spiroacenaphthene pyrroloisoquinolines with high regioselectivity is described. These compounds were prepared from 1,3-dipolar cycloaddition of an azomethine ylide generated from acenaphthenequinone and 1,2,3,4-tetrahydroisoquinoline via [1,5]-H shift, with chalcone and nitrostyrene derivatives as dipolarophiles. The structure and stereochemistry of the cycloadducts have been established by single crystal X-ray structure and spectroscopic techniques. (author)

A Scalable Method for Regioselective 3-Acylation of 2-Substituted Indoles under Basic Conditions

DEFF Research Database (Denmark)

Johansson, Karl Henrik; Urruticoechea, Andoni; Larsen, Inna

2015-01-01

Privileged structures such as 2-arylindoles are recurrent molecular scaffolds in bioactive molecules. We here present an operationally simple, high yielding and scalable method for regioselective 3-acylation of 2-substituted indoles under basic conditions using functionalized acid chlorides. The ....... The method shows good tolerance to both electron-withdrawing and donating substituents on the indole scaffold and gives ready access to a variety of functionalized 3-acylindole building blocks suited for further derivatization....

A facile regioselective synthesis of novel spiroacenaphthene pyrroloisoquinolines through 1,3-dipolar cycloaddition reactions

Energy Technology Data Exchange (ETDEWEB)

Sarrafi, Yaghoub; Asghari, Asieh; Sadatshahabi, Marzieh, E-mail: ysarrafi@umz.ac.ir [Department of Organic Chemistry, Faculty of Chemistry, University of Mazandaran (Iran, Islamic Republic of); Hamzehloueian, Mahshid [Department of Chemistry, Jouybar Branch, Islamic Azad University, Jouybar (Iran, Islamic Republic of); Alimohammadi, Kamal [Department of Chemistry, Dr. Shariati Branch, University of Farhangian, Sari (Iran, Islamic Republic of)

2013-12-01

An efficient one-pot three-component procedure for the synthesis of novel spiroacenaphthene pyrroloisoquinolines with high regioselectivity is described. These compounds were prepared from 1,3-dipolar cycloaddition of an azomethine ylide generated from acenaphthenequinone and 1,2,3,4-tetrahydroisoquinoline via [1,5]-H shift, with chalcone and nitrostyrene derivatives as dipolarophiles. The structure and stereochemistry of the cycloadducts have been established by single crystal X-ray structure and spectroscopic techniques. (author)

Dehydration Comes on Fast and Can Be Fatal

Science.gov (United States)

... can be fatal Dehydration comes on fast and can be fatal During the hot summer months,the ... and keeping hydrated. “Dehydration is very dangerous. It can lead to an emergency visit, and it can ...

Dehydration kinetics of talc at 1 bar

Science.gov (United States)

Ganguly, J.; Bose, K.

1991-01-01

Experimental results on the dehydration kinetics of talc, which is likely to be a major potential resource for water and hydrogen in carbonaceous chondrites, is presented. The rate of dehydration of an essentially pure Mg-end member natural talc, (Mg(.99)Fe(.01))3Si4O10(OH)2, was studied by measuring in situ weight change under isothermal condition at 1 bar as a function of time in the temperature range 775 to 985 C. The grain size of the starting material was 0.7 to 1 micron. It was found that the data up to 50 to 60 percent dehydration can be fitted by an equation of the form alpha = exp(-Kt(exp n)), where alpha is the weight fraction of talc remaining, K is a rate constant and n is a numerical constant for a given temperature. For any set of isothermal data, there is a major change in the value of n for larger dehydration. For up to approximately 50 percent dehydration, all rate constants can be described by an Arrheniun relation with an activation energy of 432 (+/- 30) kJ/mol; n has a nearly constant value of 0.54 between 775 and 875 C, but increases almost linearly according to n = -10.77 + 0.012T C at T greater than or equal to 875 C.

GOHAL!: sustainable membranes for alcohol dehydration

DEFF Research Database (Denmark)

Boffa, Vittorio

2017-01-01

the pristine graphene oxide membrane. The enhanced water permeability along with the good water/ethanol selectivity makes the GO-HAL membranes promising devices for alcohol dehydration technologies. This study provides a new basis for the rational design of the future generation of GO-based membranes......Treat, H2020-MSCA-RISE-2014 (n. 64555). [1] V. Boffa et. al., Carbon-based building blocks for alcohol dehydration membranes with disorder-enhanced water permeability, Carbon, under review....

Anhydrous ZnCl2: A Highly Efficient Reagent for Facile and Regioselective Conversion of Epoxides to β-Chlorohydrins

Directory of Open Access Journals (Sweden)

Ronak Eisavi

2016-01-01

Full Text Available Facile conversion of structurally different epoxides to the corresponding β-chlorohydrins was carried out successfully with anhydrous ZnCl2 in CH3CN. The reactions were carried out within 10-50 min to give β-chlorohydrins with perfect regioselectivity and high yields (80-97%.

Rehydration Capacities and Rates for Various Porcine Tissues after Dehydration

Science.gov (United States)

Meyer, Jacob P.; McAvoy, Kieran E.; Jiang, Jack

2013-01-01

The biphasic effects of liquid on tissue biomechanics are well known in cartilage and vocal folds, yet not extensively in other tissue types. Past studies have shown that tissue dehydration significantly impacts biomechanical properties and that rehydration can restore these properties in certain tissue types. However, these studies failed to consider how temporal exposure to dehydrating or rehydrating agents may alter tissue rehydration capacity, as overexposure to dehydration may permanently prevent rehydration to the initial liquid volume. Select porcine tissues were dehydrated until they reached between 100% and 40% of their initial mass. Each sample was allowed to rehydrate for 5 hours in a 0.9% saline solution, and the percent change between the initial and rehydrated mass values was calculated. Spearman correlation tests indicated a greater loss in mass despite rehydration when tissues were previously exposed to greater levels of dehydration. Additionally, Pearson correlation tests indicated the total liquid mass of samples after complete rehydration decreased when previously exposed to higher levels of dehydration. Rehydration rates were found by dehydrating tissues to 40% of their initial mass followed by rehydration in a 0.9% saline solution for 60 minutes, with mass measurements occurring in 15 minute intervals. All tissues rehydrated nonlinearly, most increasing significantly in mass up to 30 minutes after initial soaking. This study suggests the ability for tissues to rehydrate is dependent on the level of initial dehydration exposure. In vitro rehydration experiments therefore require controlled dosage and temporal exposure to dehydrating and rehydrating agents to avoid incomplete rehydration, and caution should be taken when combining different tissue types in models of hydration. PMID:24023753

In situ dehydration of yugawaralite

DEFF Research Database (Denmark)

Artioli, G.; Ståhl, Kenny; Cruciani, G.

2001-01-01

The structural response of the natural zeolite yugawaralite (CaAl2Si6O16. 4H(2)O) upon thermally induced dehydration has been studied by Rietveld analysis of temperature-resolved powder diffraction data collected in situ in the temperature range 315-791 K using synchrotron radiation. The room...... progressively disappearing as the dehydration proceeds. The yugawaralite structure reacts to the release of water molecules with small changes in the Ca-O bond distances and minor distortions of the tetrahedral framework up to about 695 K. Above this temperature the Ca coordination falls below 7 (four framework...

Methods for Human Dehydration Measurement

Science.gov (United States)

Trenz, Florian; Weigel, Robert; Hagelauer, Amelie

2018-03-01

The aim of this article is to give a broad overview of current methods for the identification and quantification of the human dehydration level. Starting off from most common clinical setups, including vital parameters and general patients' appearance, more quantifiable results from chemical laboratory and electromagnetic measurement methods will be reviewed. Different analysis methods throughout the electromagnetic spectrum, ranging from direct current (DC) conductivity measurements up to neutron activation analysis (NAA), are discussed on the base of published results. Finally, promising technologies, which allow for an integration of a dehydration assessment system in a compact and portable way, will be spotted.

Comparison of Gas Dehydration Methods based on Energy ...

African Journals Online (AJOL)

PROF HORSFALL

Natural Gas) dehydration to carry out the dehydration process and suitability of use on the basis of energy ... pipelines and distribution for burning by end users, natural gas must ... A good account of energy and material balance will create a ...

40 CFR 63.765 - Glycol dehydration unit process vent standards.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Glycol dehydration unit process vent... Facilities § 63.765 Glycol dehydration unit process vent standards. (a) This section applies to each glycol dehydration unit subject to this subpart with an actual annual average natural gas flowrate equal to or...

40 CFR 63.1275 - Glycol dehydration unit process vent standards.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Glycol dehydration unit process vent... Facilities § 63.1275 Glycol dehydration unit process vent standards. (a) This section applies to each glycol dehydration unit subject to this subpart with an actual annual average natural gas flowrate equal to or...

Room temperature inorganic polycondensation of oxide (Cu2O and ZnO) nanoparticles and thin films preparation by the dip-coating technique

International Nuclear Information System (INIS)

Salek, G.; Tenailleau, C.; Dufour, P.; Guillemet-Fritsch, S.

2015-01-01

Oxide thin solid films were prepared by dip-coating into colloidal dispersions of oxide nanoparticles stabilized at room temperature without the use of chelating or complex organic dispersing agents. Crystalline oxide nanoparticles were obtained by inorganic polycondensation and characterized by X-ray diffraction and field emission gun scanning electron microscopy. Water and ethanol synthesis and solution stabilization of oxide nanoparticle method was optimized to prepare two different structural and compositional materials, namely Cu 2 O and ZnO. The influence of hydrodynamic parameters over the particle shape and size is discussed. Spherical and rod shape nanoparticles were formed for Cu 2 O and ZnO, respectively. Isoelectric point values of 7.5 and 8.2 were determined for cuprous and zinc oxides, respectively, after zeta potential measurements. A shear thinning and thixotropic behavior was observed in both colloidal sols after peptization at pH ~ 6 with dilute nitric acid. Every colloidal dispersion stabilized in a low cost and environmentally friendly azeotrope solution composed of 96 vol.% of ethanol with water was used for the thin film preparation by the dip-coating technique. Optical properties of the light absorber cuprous oxide and transparent zinc oxide thin solid films were characterized by means of transmittance and reflectance measurements (300–1100 nm). - Highlights: • Room temperature inorganic polycondensation of crystalline oxides • Water and ethanol synthesis and solution stabilization of oxide nanoparticles • Low cost method for thin solid film preparation

Upstream petroleum industry glycol dehydrator benzene emissions status report

International Nuclear Information System (INIS)

1999-07-01

The population of dehydrators referred to are located in the Western Sedimentary Basin in northeast British Columbia, Alberta and Saskatchewan, and includes units installed at wellsites, compressor stations, gas plants, central crude oil treating facilities, and reservoir or salt cavern gas storage facilities. Benzene emissions from the still column vent on glycol dehydrators occur as a result of glycol's strong affinity for aromatic hydrocarbons, including benzene. A study was carried out to: 1) develop a list of oil and gas companies operating in Canada, 2) develop an equipment and benzene emissions inventory of glycol dehydrators, 3) develop a database in Microsoft Access format to gather and maintain inventory and emission data, 4) evaluate and validate at least 10% of the reported data, 5) develop a list of companies that manufacture dehydrators and incinerators to determine how many new dehydrators were sold for use in Canada in 1998, and 6) prepare a report summarizing findings and recommendations. The companies included in the survey were the oil and gas companies identified by the Nickels' Oil and Gas Index and others provided by CAPP, CGA, and SEPAC. The project was carried out to gather glycol dehydrator equipment and still column vent benzene emissions information. 8 refs

Radioactive waste slurry dehydrating and drum filling device

International Nuclear Information System (INIS)

Ichihashi, Toshio; Abe, Kazuaki; Hasegawa, Akira

1981-01-01

Purpose: To obtain a device for simultaneously filling and dehydrating radioactive waste in a waste can without the necessity of a special device for dehydration. Constitution: This device includes a radioactive waste storage tank, a pump for supplying the waste from the tank to a can, a drain tube having a filter at the lower end and installed displaceable in the axial direction of the can, and a drain pump. The slurry stored in the radioactive waste storage tank is supplied by the pump to the can, and the feedwater in the slurry is removed by another pump through a drain pipe having a filter which does not pass solid content from the can. Accordingly, as the slurry is filled in the can, the feedwater contained therein is removed. Consequently, it can simultaneously dehydrate and fill the dehydrated waste in the can. (Yoshihara, H.)

A Study of the Polycondensation of (Tetrahydroxy(TetraarylCyclotetrasiloxanes under Equilibrium and Non-Equilibrium Conditions in the Presence and Absence of Montmorillonite

Directory of Open Access Journals (Sweden)

Nataliya N. Makarova

2018-04-01

Full Text Available Oligo- and polycyclosiloxanes were obtained by the polycondensation of (tetrahydroxy(tetraarylcyclotetrasiloxanes in equilibrium and non-equilibrium conditions in the presence and absence of montmorillonite (MMT. Their composition and the structures of their components were investigated by infrared (IR spectroscopy, 29Si nuclear magnetic resonance (NMR spectroscopy, atmospheric pressure chemical ionization (APCI mass spectrometry, powder X-ray diffraction (XRD, and gel-penetrating chromatography (GPC. Also, a comparison of polymers formed in the presence of MMT and via anionic polymerization was performed showing differences in their structures.

Dehydration in the Elderly: A Review Focused on Economic Burden.

Science.gov (United States)

Frangeskou, M; Lopez-Valcarcel, B; Serra-Majem, L

2015-06-01

Dehydration is the most common fluid and electrolyte problem among elderly patients. It is reported to be widely prevalent and costly to individuals and to the health care system. The purpose of this review is to summarize the literature on the economic burden of dehydration in the elderly. A comprehensive search of several databases from database inception to November 2013, only in English language, was conducted. The databases included Pubmed and ISI Web of Science. The search terms «dehydration» / "hyponaremia" / "hypernatremia" AND «cost» AND «elderly» were used to search for comparative studies of the economic burden of dehydration. A total of 15 papers were identified. Dehydration in the elderly is an independent factor of higher health care expenditures. It is directly associated with an increase in hospital mortality, as well as with an increase in the utilization of ICU, short and long term care facilities, readmission rates and hospital resources, especially among those with moderate to severe hyponatremia. Dehydration represents a potential target for intervention to reduce healthcare expenditures and improve patients' quality of life.

Kinetic isotope effect in dehydration of ionic solids. II. The kinetics of dehydration of calcium oxalate monohydrate

International Nuclear Information System (INIS)

Manche, E.P.; Carroll, B.

1977-01-01

The kinetics of the isothermal dehydration of the protonated and deuterated monohydrate of calcium oxalate has been investigated at 120, 150, and 170 0 C. The rate of dehydration for these salts was found to be k/sub H//k/sub D/ = 1.025 +- 0.012. This result rules out the enormous kinetic isotope effect as given in the literature. An isotope effect of a few percent is not ruled out; this magnitude is in keeping with that found by Heinzinger in other dehydration processes. An estimated difference of about 150 cal/mol between the heat of desorption for H 2 O and D 2 O should have led to a ratio, k/sub h//k/sub D/ = 1.20. The smaller observed ratio has been explained on the basis of a compensation effect and may be considered an example of the Barclay--Butler correlation

What's the Big Sweat about Dehydration? (For Kids)

Science.gov (United States)

... First Aid & Safety Doctors & Hospitals Videos Recipes for Kids Kids site Sitio para niños How the Body Works ... for Educators Search English Español Dehydration KidsHealth / For Kids / Dehydration Print en español ¿Por qué es tan ...

Highly efficient and regioselective acylation of pharmacologically interesting cordycepin catalyzed by lipase in the eco-friendly solvent 2-methyltetrahydrofuran.

Science.gov (United States)

Chen, Zhi-Gang; Zhang, Dan-Ni; Cao, Lin; Han, Yong-Bin

2013-04-01

A total of nine lipases and three proteases were tested for enzymatic regioselective acylation(s) of cordycepin with vinyl acetate in organic media. The highest conversion with better initial reaction rate was achieved with immobilized Candida antarctica lipase B (Novozym 435). An eco-friendly solvent 2-methyltetrahydrofuran (MeTHF) was thought to be the most suitable reaction medium. Novozym 435 was found to be a useful biocatalyst for the 25-g scale syntheses of cordycepin acetate (96.2% isolated yield), and the biocatalyst displayed excellent regioselectivity and high operational stability during the transformation. The 5'-substituted cordycepin derivative was the sole detectable product from each acylation reaction. Novozym 435 could be recycled for the synthesis of cordycepin derivative on a 25-g scale and 63% of its original activity was maintained after being reused for 7 batches. MeTHF could be considered as an eco-friendly solvent for the large scale use in biotransformation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dehydration and crystallization kinetics of zirconia-yttria gels

International Nuclear Information System (INIS)

Ramanathan, S.; Muraleedharan, R.V.; Roy, S.K.; Nayar, P.K.K.

1995-01-01

Zirconia and zirconia-yttria gels containing 4 and 8 mol% yttria were obtained by coprecipitation and drying at 373 K. The dehydration and crystallization behavior of the dried gels was studied by DSC, TG, and XRD. The gels undergo elimination of water over a wide temperature range of 373--673 K. The peak temperature of the endotherm corresponding to dehydration and the kinetic constants for the process were not influenced by the yttria content of the gel. The enthalpy of dehydration observed was in good agreement with the heat of vaporization data. The dehydration was followed by a sharp exothermic crystallization process. The peak temperature of the exotherm and the activation energy of the process increased with an increase in yttria content, while the enthalpy of crystallization showed a decrease. The ''glow effect'' reduced with increasing yttria content. Pure zirconia crystallizes in the tetragonal form while the zirconia containing 4 and 8 mol% yttria appears to crystallize in the cubic form

Survey of quality indicators in commercial dehydrated fruits.

Science.gov (United States)

Megías-Pérez, Roberto; Gamboa-Santos, Juliana; Soria, Ana Cristina; Villamiel, Mar; Montilla, Antonia

2014-05-01

Physical and chemical quality parameters (dry matter, aw, protein, carbohydrates, vitamin C, 2-furoylmethyl amino acids, rehydration ratio and leaching loss) have been determined in 30 commercial dehydrated fruits (strawberry, blueberry, raspberry, cranberry, cherry, apple, grapefruit, mango, kiwifruit, pineapple, melon, coconut, banana and papaya). For comparison purposes, strawberry samples processed in the laboratory by freeze-drying and by convective drying were used as control samples. Overall quality of dehydrated fruits seemed to be greatly dependent on processing conditions and, in a cluster analysis, samples which were presumably subjected to osmotic dehydration were separated from the rest of fruits. These samples presented the lowest concentration of vitamin C and the highest evolution of Maillard reaction, as evidenced by its high concentration of 2-furoylmethyl amino acids. This is the first study on the usefulness of this combination of chemical and physical indicators to assess the overall quality of commercial dehydrated fruits. Copyright © 2013 Elsevier Ltd. All rights reserved.

Microencapsulation of butyl stearate as a phase change material by interfacial polycondensation in a polyurea system

Energy Technology Data Exchange (ETDEWEB)

Chen Liang [College of Material Science and Engineering, Nanjing University of Technology, Nanjing 210009 (China)], E-mail: doseng_1982@hotmail.com; Xu Lingling; Shang Hongbo; Zhang Zhibin [College of Material Science and Engineering, Nanjing University of Technology, Nanjing 210009 (China)

2009-03-15

For the last 20 years, microencapsulated phase change materials (MicroPCMs), which combine microencapsulation technology and phase change material, have been attracted more and more interest. By overcoming some limitations of the PCMs, the MicroPCMs improve the efficiency of PCMs and make it possible to apply PCMs in many areas. In this experiment, polyurea microcapsules containing phase change materials were prepared using interfacial polycondensation method. Toluene-2,4-diisocyanate (TDI) and ethylenediamine (EDA) were chosen as monomers. Butyl stearate was employed as a core material. The MicroPCMs' properties have been characterized by dry weight analysis, differential scanning calorimetry, Fourier transform IR spectra analysis and optical microscopy. The results show that the MicroPCMs were synthesized successfully and that, the phase change temperature was about 29 deg. C, the latent heat of fusion was about 80 J g{sup -1}, the particle diameter was 20-35 {mu}m.

Microencapsulation of butyl stearate as a phase change material by interfacial polycondensation in a polyurea system

International Nuclear Information System (INIS)

Chen Liang; Xu Lingling; Shang Hongbo; Zhang Zhibin

2009-01-01

For the last 20 years, microencapsulated phase change materials (MicroPCMs), which combine microencapsulation technology and phase change material, have been attracted more and more interest. By overcoming some limitations of the PCMs, the MicroPCMs improve the efficiency of PCMs and make it possible to apply PCMs in many areas. In this experiment, polyurea microcapsules containing phase change materials were prepared using interfacial polycondensation method. Toluene-2,4-diisocyanate (TDI) and ethylenediamine (EDA) were chosen as monomers. Butyl stearate was employed as a core material. The MicroPCMs' properties have been characterized by dry weight analysis, differential scanning calorimetry, Fourier transform IR spectra analysis and optical microscopy. The results show that the MicroPCMs were synthesized successfully and that, the phase change temperature was about 29 deg. C, the latent heat of fusion was about 80 J g -1 , the particle diameter was 20-35 μm

Microencapsulation of butyl stearate as a phase change material by interfacial polycondensation in a polyurea system

Energy Technology Data Exchange (ETDEWEB)

Liang, Chen; Lingling, Xu; Hongbo, Shang; Zhibin, Zhang [College of Material Science and Engineering, Nanjing University of Technology, Nanjing 210009 (China)

2009-03-15

For the last 20 years, microencapsulated phase change materials (MicroPCMs), which combine microencapsulation technology and phase change material, have been attracted more and more interest. By overcoming some limitations of the PCMs, the MicroPCMs improve the efficiency of PCMs and make it possible to apply PCMs in many areas. In this experiment, polyurea microcapsules containing phase change materials were prepared using interfacial polycondensation method. Toluene-2,4-diisocyanate (TDI) and ethylenediamine (EDA) were chosen as monomers. Butyl stearate was employed as a core material. The MicroPCMs' properties have been characterized by dry weight analysis, differential scanning calorimetry, Fourier transform IR spectra analysis and optical microscopy. The results show that the MicroPCMs were synthesized successfully and that, the phase change temperature was about 29 C, the latent heat of fusion was about 80 J g{sup -1}, the particle diameter was 20-35 {mu}m. (author)

Dehydration of alcohols using solid acid catalysts

OpenAIRE

Cholerton, Mary

2014-01-01

Solid acid catalysts were prepared through silicon substitution into aluminophosphate frameworks. Silicon incorporation was confirmed using solid state nuclear magnetic resonance spectroscopy. The nature of the acid sites generated was determined using Fourier Transform infrared spectroscopy. These materials were tested as catalysts for the dehydration of ethanol to ethylene at low operating temperatures. The materials were active for dehydration of ethanol to ethylene with significant differ...

Studying of the dehydration process of uranyl nitrate hexahydrate (Unh)

International Nuclear Information System (INIS)

Badalov, A.; Kamalov, J.J.; Homidov, B.J.; Mirsaidov, I.U.; Eshbekov, N.R.

2005-01-01

By the tensimeteric method is studying the dehydration process of uranyl nitrate hexahydrate (Unh). It is shown, that the temperature interval 300-400 K in equilibrium conditions the dehydration process of Unh runs in three stages. According to the equations of dependence of saturated steam pressure from temperature, the thermodynamic characteristics of each stage of the dehydration process of Unh are calculated

Ethanol dehydration

OpenAIRE

Ana María Uyazán; Iván Dario Gil; J L Aguilar; Gerardo Rodríguez Niño; Luis Alfonso Caicedo

2004-01-01

This review outlines ethanol dehydration processes and their most important characteristics. It also deals with the main operating variables and some criteria used in designing the separation scheme. A differentiation is made between processes involving liquid steam balance in separation operations and those doing it by screening the difference in molecule size. The last part presents a comparison between the three main industrial processes, stressing their stengths and weaknesses from the op...

Rates of Hospitalization for Dehydration Following Hurricane Sandy in New Jersey.

Science.gov (United States)

Swerdel, Joel N; Rhoads, George G; Cosgrove, Nora M; Kostis, John B

2016-04-01

Hurricane Sandy, one of the most destructive natural disasters in New Jersey history, made landfall on October 29, 2012. Prolonged loss of electrical power and extensive infrastructure damage restricted access for many to food and water. We examined the rate of dehydration in New Jersey residents after Hurricane Sandy. We obtained data from 2008 to 2012 from the Myocardial Infarction Data Acquisition System (MIDAS), a repository of in-patient records from nonfederal New Jersey hospitals (N=517,355). Patients with dehydration had ICD-9-CM discharge diagnosis codes for dehydration, volume depletion, and/or hypovolemia. We used log-linear modeling to estimate the change in in-patient hospitalizations for dehydration comparing 2 weeks after Sandy with the same period in the previous 4 years (2008-2011). In-patient hospitalizations for dehydration were 66% higher after Sandy than in 2008-2011 (rate ratio [RR]: 1.66; 95% confidence interval [CI]: 1.50, 1.84). Hospitalizations for dehydration in patients over 65 years of age increased by nearly 80% after Sandy compared with 2008-2011 (RR: 1.79; 95% CI: 1.58, 2.02). Sandy was associated with a marked increase in hospitalizations for dehydration. Reducing the rate of dehydration following extreme weather events is an important public health concern that needs to be addressed, especially in those over 65 years of age.

External validation and comparison of three pediatric clinical dehydration scales.

Science.gov (United States)

Jauregui, Joshua; Nelson, Daniel; Choo, Esther; Stearns, Branden; Levine, Adam C; Liebmann, Otto; Shah, Sachita P

2014-01-01

To prospectively validate three popular clinical dehydration scales and overall physician gestalt in children with vomiting or diarrhea relative to the criterion standard of percent weight change with rehydration. We prospectively enrolled a non-consecutive cohort of children ≤ 18 years of age with an acute episode of diarrhea or vomiting. Patient weight, clinical scale variables and physician clinical impression, or gestalt, were recorded before and after fluid resuscitation in the emergency department and upon hospital discharge. The percent weight change from presentation to discharge was used to calculate the degree of dehydration, with a weight change of ≥ 5% considered significant dehydration. Receiver operating characteristics (ROC) curves were constructed for each of the three clinical scales and physician gestalt. Sensitivity and specificity were calculated based on the best cut-points of the ROC curve. We approached 209 patients, and of those, 148 were enrolled and 113 patients had complete data for analysis. Of these, 10.6% had significant dehydration based on our criterion standard. The Clinical Dehydration Scale (CDS) and Gorelick scales both had an area under the ROC curve (AUC) statistically different from the reference line with AUCs of 0.72 (95% CI 0.60, 0.84) and 0.71 (95% CI 0.57, 0.85) respectively. The World Health Organization (WHO) scale and physician gestalt had AUCs of 0.61 (95% CI 0.45, 0.77) and 0.61 (0.44, 0.78) respectively, which were not statistically significant. The Gorelick scale and Clinical Dehydration Scale were fair predictors of dehydration in children with diarrhea or vomiting. The World Health Organization scale and physician gestalt were not helpful predictors of dehydration in our cohort.

Prognostic value of amplitude-integrated electroencephalography in neonates with hypernatremic dehydration.

Science.gov (United States)

Tekgunduz, Kadir Şerafettin; Caner, Ibrahim; Eras, Zeynep; Taştekin, Ayhan; Tan, Huseyin; Dinlen, Nurdan

2014-05-01

Hypernatremic dehydration in neonates is a condition that develops due to inadequate fluid intake and it may lead to cerebral damage. We aimed to determine whether there was an association between serum sodium levels on admission and aEEG patterns and prognosis, as well as any association between aEEG findings and survival rates and long-term prognosis. The present study included all term infants hospitalized for hypernatremic dehydration in between January 2010 and May 2011. Infants were monitored by aEEG. At 2 years of age, we performed a detailed evaluation to assess the impact of hypernatremic dehydration on the neurodevelopmental outcome. Twenty-one infants were admitted to the neonatal intensive care unit for hypernatremic dehydration. A correlation was found between increased serum sodium levels and aEEG abnormalities. Neurodevelopmental assessment was available for 17 of the 21 infants. The results revealed that hypernatremic dehydration did not adversely affect the long-term outcomes. The follow-up of newborns after discharge is key to determine the risks associated with hypernatremic dehydration. Our results suggest that hypernatremic dehydration had no impact on the long-term outcome. In addition, continuous aEEG monitoring could provide information regarding early prognosis and mortality.

Peculiarities of dehydration of calcium dodeca- and hexavanadates

International Nuclear Information System (INIS)

Koryakova, O.V.; Perelyaeva, L.A.; Zabolotskaya, E.V.; Medvedeva, N.I.; Ivakin, A.A.

1982-01-01

Infrared spectroscopic, electron paramagentic resonance, X-ray diffraction and thermogravimetric methods were used to study the process and dehydration products of CaV 12 O 31 x12H 2 O and CaV 6 O 16 x6H 2 O calcium dodeca-and hexavanadates. The dependence of chemical composition on dehydration temperature was established. It was revealed that investigated polyvanadates contain two types of water crystallization and coordinationally linked-one. Complete dehydration (300-400 deg C) leads to irreversible structural changes and formation of oxide vanadium bronze. The ''final'' product (t > 500 deg C) is the mixture of vanadium pentaoxide and calcium metavanadate

Room temperature inorganic polycondensation of oxide (Cu{sub 2}O and ZnO) nanoparticles and thin films preparation by the dip-coating technique

Energy Technology Data Exchange (ETDEWEB)

Salek, G.; Tenailleau, C., E-mail: tenailleau@chimie.ups-tlse.fr; Dufour, P.; Guillemet-Fritsch, S.

2015-08-31

Oxide thin solid films were prepared by dip-coating into colloidal dispersions of oxide nanoparticles stabilized at room temperature without the use of chelating or complex organic dispersing agents. Crystalline oxide nanoparticles were obtained by inorganic polycondensation and characterized by X-ray diffraction and field emission gun scanning electron microscopy. Water and ethanol synthesis and solution stabilization of oxide nanoparticle method was optimized to prepare two different structural and compositional materials, namely Cu{sub 2}O and ZnO. The influence of hydrodynamic parameters over the particle shape and size is discussed. Spherical and rod shape nanoparticles were formed for Cu{sub 2}O and ZnO, respectively. Isoelectric point values of 7.5 and 8.2 were determined for cuprous and zinc oxides, respectively, after zeta potential measurements. A shear thinning and thixotropic behavior was observed in both colloidal sols after peptization at pH ~ 6 with dilute nitric acid. Every colloidal dispersion stabilized in a low cost and environmentally friendly azeotrope solution composed of 96 vol.% of ethanol with water was used for the thin film preparation by the dip-coating technique. Optical properties of the light absorber cuprous oxide and transparent zinc oxide thin solid films were characterized by means of transmittance and reflectance measurements (300–1100 nm). - Highlights: • Room temperature inorganic polycondensation of crystalline oxides • Water and ethanol synthesis and solution stabilization of oxide nanoparticles • Low cost method for thin solid film preparation.

Dehydration processes using membranes with hydrophobic coating

Science.gov (United States)

Huang, Yu; Baker, Richard W; Aldajani, Tiem; Ly, Jennifer

2013-07-30

Processes for removing water from organic compounds, especially polar compounds such as alcohols. The processes include a membrane-based dehydration step, using a membrane that has a dioxole-based polymer selective layer or the like and a hydrophilic selective layer, and can operate even when the stream to be treated has a high water content, such as 10 wt % or more. The processes are particularly useful for dehydrating ethanol.

Designer HF-Based Fluorination Reagent: Highly Regioselective Synthesis of Fluoroalkenes and gem-Difluoromethylene Compounds from Alkynes

Science.gov (United States)

2015-01-01

Hydrogen fluoride (HF) and selected nonbasic and weakly coordinating (toward cationic metal) hydrogen-bond acceptors (e.g., DMPU) can form stable complexes through hydrogen bonding. The DMPU/HF complex is a new nucleophilic fluorination reagent that has high acidity and is compatible with cationic metal catalysts. The gold-catalyzed mono- and dihydrofluorination of alkynes using the DMPU/HF complex yields synthetically important fluoroalkenes and gem-difluoromethlylene compounds regioselectively. PMID:25260170

Regioselective C-H imidation of five-membered heterocyclic compounds through a metal catalytic or organocatalytic approach.

Science.gov (United States)

Wang, Xin; Sun, Kai; Lv, Yunhe; Ma, Fengji; Li, Gang; Li, Donghui; Zhu, Zhonghong; Jiang, Yongqing; Zhao, Feng

2014-12-01

An efficient method for the synthesis of 2-amino and β-amino five-membered heterocyclic derivatives that are closely related to a variety of biologically active natural products is described. Regioselectivity was achieved through a metal catalytic or organocatalytic approach. Preliminary studies on the reaction mechanism suggest a radical imidation pathway; however, further studies are needed to verify the mechanism. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production and evaluation of precooked dehydrated unripe banana ...

African Journals Online (AJOL)

No significant change in total aerobic counts or yeasts and moulds counts occurred in dehydrated banana slices packaged in 250 gauge polyethylene bags and stored at ambient temperature for 3 months. The slices were found to be high in starch (~68.5%) and minerals. When shallow fried, the dehydrated banana slices ...

Osmotic dehydration of fruit and berry raw materials in the food industry

Directory of Open Access Journals (Sweden)

N. A. Gribova

2017-01-01

Full Text Available Osmotic dehydration has recently received more attention as an effective method of preserving fruits and berries. Osmosis is a simple process that facilitates the processing of fruits and berries in order to preserve the original characteristics, namely nutritional value and organoleptic properties: color, aroma and texture. Osmotic dehydration has found wide application in the preservation of food products, as the activity of water in fruits and berries decreases, in some of them up to 90% of water is contained. The process of osmotic dehydration with the help of various agents is less energy-intensive than the process of drying or freezing, since it can be processed at ambient temperature. Osmotic dehydration has potential advantages in preserving the quality of food and in maintaining healthy food for the food industry. Treatment includes dehydration of fruits and berries by an osmotic agent followed by dehydration in dry or frozen apparatus where the moisture content decreases and the product becomes more stable. This process is a partial dewatering process to provide improved product quality compared to conventional drying processes or freezing. The purpose of studying osmotic dehydration is to identify the advantages and disadvantages in the treatment of osmotic agents. Various aspects of osmotic dehydration technology are considered, namely the solutions used, the characteristics of solutions, the effect of variable processes and the qualitative characteristics of osmo-dehydrated products. Factors of osmotic dehydration that depend on the osmotic agent, concentration of solute, temperature, time, size, shape and compactness of the material, mixing and the ratio of the solution to the samples.

Measured degree of dehydration in children and adolescents with type 1 diabetic ketoacidosis.

Science.gov (United States)

Ugale, Judith; Mata, Angela; Meert, Kathleen L; Sarnaik, Ashok P

2012-03-01

Successful management of diabetic ketoacidosis depends on adequate rehydration while avoiding cerebral edema. Our objectives are to 1) measure the degree of dehydration in children with type 1 diabetes mellitus and diabetic ketoacidosis based on change in body weight; and 2) investigate the relationships between measured degree of dehydration and clinically assessed degree of dehydration, severity of diabetic ketoacidosis, and routine serum laboratory values. Prospective observational study. University-affiliated tertiary care children's hospital. Sixty-six patients dehydration was based on the difference between admission and plateau weights. Clinical degree of dehydration was assessed by physical examination and severity of diabetic ketoacidosis was assessed by blood gas values as defined by international guidelines. Laboratory values obtained on admission included serum glucose, urea nitrogen, sodium, and osmolality. Median measured degree of dehydration was 5.2% (interquartile range, 3.1% to 7.8%). Fourteen (21%) patients were clinically assessed as mild dehydration, 49 (74%) as moderate, and three (5%) as severe. Patients clinically assessed as moderately dehydrated had a greater measured degree of dehydration (5.8%; interquartile range, 3.6% to 9.6%) than those assessed as mildly dehydrated (3.7%; interquartile range, 2.3% to 6.4%) or severely dehydrated (2.5%; interquartile range, 2.3% to 2.6%). Nine (14%) patients were assessed as mild diabetic ketoacidosis, 18 (27%) as moderate, and 39 (59%) as severe. Diabetic ketoacidosis severity groups did not differ in measured degree of dehydration. Variables independently associated with measured degree of dehydration included serum urea nitrogen and sodium concentration on admission. Hydration status in children with diabetic ketoacidosis cannot be accurately assessed by physical examination or blood gas values. Fluid therapy based on maintenance plus 6% deficit replacement is reasonable for most patients.

Olefination of Electron-Deficient Alkenes with Allyl Acetate: Stereo- and Regioselective Access to (2Z,4E)-Dienamides.

Science.gov (United States)

Li, Feifei; Yu, Chunbing; Zhang, Jian; Zhong, Guofu

2016-09-16

A Ru-catalyzed direct olefination of electron-deficient alkenes with allyl acetate via C-H bond activation is disclosed. By using N,N-disubstituted aminocarbonyl as the directing group, this external oxidant-free protocol resulted in high reaction efficiency and good stereo- and regioselectivities, which opens a novel synthetic passway for access to (Z,E)-butadiene skeletons.

Dehydration kinetics of boehmite in the temperature range 723-873 K

Energy Technology Data Exchange (ETDEWEB)

Xu, Bingan, E-mail: bingan.xu@csiro.au [A.J. Parker Cooperative Research Centre for Integrated Hydrometallurgy Solutions, CSIRO Light Metals Flagship (Division of Process Science and Engineering), PO Box 7229, Karawara, WA 6152 (Australia); Smith, Peter [A.J. Parker Cooperative Research Centre for Integrated Hydrometallurgy Solutions, CSIRO Light Metals Flagship (Division of Process Science and Engineering), PO Box 7229, Karawara, WA 6152 (Australia)

2012-03-10

Highlights: Black-Right-Pointing-Pointer The dehydration of boehmite is a complex topotactic process. Black-Right-Pointing-Pointer The process is chemical control with a diffusion complication as the reaction progresses. Black-Right-Pointing-Pointer Al cation diffusion is the rate-limiting step. Black-Right-Pointing-Pointer The reaction rates predicted by the model-free method agree well with the measured values. - Abstract: The dehydration kinetics of boehmite prepared from the hydrothermal transformation of gibbsite has been comprehensively studied to clarify the mechanism of the dehydration process using a thermogravimetric technique under both isothermal and non-isothermal conditions. Selected residues were examined by XRD, SEM, TEM and selected area electron diffraction (SAED). Results indicate that the dehydration process is a topotactic reaction which brings about {gamma}-Al{sub 2}O{sub 3} with porous microstructure and poor crystallinity. The kinetic data were analysed using the model-free (isoconversional) methods. The results indicate that the activation energy of the dehydration process depends on the reaction extent, signifying the dehydration process is chemical controlled with a diffusion complication as the reaction extent increases. Prediction of the dehydration extent was accomplished using the kinetic parameter of the non-isothermal process and the isoconversional method. The predicted rate is in a reasonably good agreement with the measured values. Finally the mechanism of the dehydration process is discussed based on the auxiliary results from the physical examination of the reacted residues and the kinetic behaviour.

External validation and comparison of three pediatric clinical dehydration scales.

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Joshua Jauregui

Full Text Available OBJECTIVE: To prospectively validate three popular clinical dehydration scales and overall physician gestalt in children with vomiting or diarrhea relative to the criterion standard of percent weight change with rehydration. METHODS: We prospectively enrolled a non-consecutive cohort of children ≤ 18 years of age with an acute episode of diarrhea or vomiting. Patient weight, clinical scale variables and physician clinical impression, or gestalt, were recorded before and after fluid resuscitation in the emergency department and upon hospital discharge. The percent weight change from presentation to discharge was used to calculate the degree of dehydration, with a weight change of ≥ 5% considered significant dehydration. Receiver operating characteristics (ROC curves were constructed for each of the three clinical scales and physician gestalt. Sensitivity and specificity were calculated based on the best cut-points of the ROC curve. RESULTS: We approached 209 patients, and of those, 148 were enrolled and 113 patients had complete data for analysis. Of these, 10.6% had significant dehydration based on our criterion standard. The Clinical Dehydration Scale (CDS and Gorelick scales both had an area under the ROC curve (AUC statistically different from the reference line with AUCs of 0.72 (95% CI 0.60, 0.84 and 0.71 (95% CI 0.57, 0.85 respectively. The World Health Organization (WHO scale and physician gestalt had AUCs of 0.61 (95% CI 0.45, 0.77 and 0.61 (0.44, 0.78 respectively, which were not statistically significant. CONCLUSION: The Gorelick scale and Clinical Dehydration Scale were fair predictors of dehydration in children with diarrhea or vomiting. The World Health Organization scale and physician gestalt were not helpful predictors of dehydration in our cohort.

Which Frail Older People Are Dehydrated? The UK DRIE Study.

Science.gov (United States)

Hooper, Lee; Bunn, Diane K; Downing, Alice; Jimoh, Florence O; Groves, Joyce; Free, Carol; Cowap, Vicky; Potter, John F; Hunter, Paul R; Shepstone, Lee

2016-10-01

Water-loss dehydration in older people is associated with increased mortality and disability. We aimed to assess the prevalence of dehydration in older people living in UK long-term care and associated cognitive, functional, and health characteristics. The Dehydration Recognition In our Elders (DRIE) cohort study included people aged 65 or older living in long-term care without heart or renal failure. In a cross-sectional baseline analysis, we assessed serum osmolality, previously suggested dehydration risk factors, general health, markers of continence, cognitive and functional health, nutrition status, and medications. Univariate linear regression was used to assess relationships between participant characteristics and serum osmolality, then associated characteristics entered into stepwise backwards multivariate linear regression. DRIE included 188 residents (mean age 86 years, 66% women) of whom 20% were dehydrated (serum osmolality >300 mOsm/kg). Linear and logistic regression suggested that renal, cognitive, and diabetic status were consistently associated with serum osmolality and odds of dehydration, while potassium-sparing diuretics, sex, number of recent health contacts, and bladder incontinence were sometimes associated. Thirst was not associated with hydration status. DRIE found high prevalence of dehydration in older people living in UK long-term care, reinforcing the proposed association between cognitive and renal function and hydration. Dehydration is associated with increased mortality and disability in older people, but trials to assess effects of interventions to support healthy fluid intakes in older people living in residential care are needed to enable us to formally assess causal direction and any health benefits of increasing fluid intakes. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Preparation of hydrophilic PVDF/PPTA blend membranes by in situ polycondensation and its application in the treatment of landfill leachate

International Nuclear Information System (INIS)

Li, Hongbin; Shi, Wenying; Zhang, Yufeng; Zhou, Rong; Zhang, Haixia

2015-01-01

Graphical abstract: - Highlights: • High modulus PPTA molecules were introduced into PVDF membrane matrix through in situ polycondensation. • Membrane surface hydrophilicity and mechanical strength were improved. • An enhanced antifouling property was obtained when blend membrane was applied in the MBR in the treatment of landfill leachate. • Blend membrane also showed a relatively high removal rate of chemical oxygen demand (COD) and chrom. - Abstract: High modulus poly(p-phenylene terephtalamide) (PPTA) reinforced composites are of great scientific interests. But the thermodynamic difference makes the polymer pairs incompatible and endows the composites with inferior physical-chemical properties. In this study, hydrophilic poly(vinylidene fluoride) (PVDF)/poly(p-phenylene terephtalamide) (PPTA) blend membrane with improved hydrophilicity and mechanical strength was prepared through in situ polycondensation of p-phenylene diamine (PPD) and terephthaloyl chloride (TPC) in PVDF solution and subsequent immersion precipitation phase inversion process. The effects of PPTA concentration in polymer dopes on membrane formation process, structure, morphology and performance were systematically investigated. The results showed that thermodynamically, PPTA acted as a demixing enhancer which accelerated the phase inversion process. Dynamically, liquid-liquid phase separation was still in control of membrane formation process especially in the later period, whereas the addition of PPTA mainly promoted the early emergence of the liquid-liquid demixing. The surface hydrophilicity, ant-fouling properties and mechanical strength were significantly improved when PPTA content was 17 wt%. When PPTA content increased to 26 wt%, membrane bursting pressure increased to nearly 0.6 MPa which was 1.5 times higher than that of PVDF membrane. The resultant PVDF/PPTA blend membrane exhibited an improved antifouling property than that of PVDF membrane when applied in the MBR in the

Preparation of hydrophilic PVDF/PPTA blend membranes by in situ polycondensation and its application in the treatment of landfill leachate

Energy Technology Data Exchange (ETDEWEB)

Li, Hongbin, E-mail: qinyu1105@126.com [School of Textiles Engineering, Henan Institute of Engineering, Zhengzhou, 450007 (China); Shi, Wenying [School of Textiles Engineering, Henan Institute of Engineering, Zhengzhou, 450007 (China); Zhang, Yufeng [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China); Zhou, Rong; Zhang, Haixia [School of Textiles Engineering, Henan Institute of Engineering, Zhengzhou, 450007 (China)

2015-08-15

Graphical abstract: - Highlights: • High modulus PPTA molecules were introduced into PVDF membrane matrix through in situ polycondensation. • Membrane surface hydrophilicity and mechanical strength were improved. • An enhanced antifouling property was obtained when blend membrane was applied in the MBR in the treatment of landfill leachate. • Blend membrane also showed a relatively high removal rate of chemical oxygen demand (COD) and chrom. - Abstract: High modulus poly(p-phenylene terephtalamide) (PPTA) reinforced composites are of great scientific interests. But the thermodynamic difference makes the polymer pairs incompatible and endows the composites with inferior physical-chemical properties. In this study, hydrophilic poly(vinylidene fluoride) (PVDF)/poly(p-phenylene terephtalamide) (PPTA) blend membrane with improved hydrophilicity and mechanical strength was prepared through in situ polycondensation of p-phenylene diamine (PPD) and terephthaloyl chloride (TPC) in PVDF solution and subsequent immersion precipitation phase inversion process. The effects of PPTA concentration in polymer dopes on membrane formation process, structure, morphology and performance were systematically investigated. The results showed that thermodynamically, PPTA acted as a demixing enhancer which accelerated the phase inversion process. Dynamically, liquid-liquid phase separation was still in control of membrane formation process especially in the later period, whereas the addition of PPTA mainly promoted the early emergence of the liquid-liquid demixing. The surface hydrophilicity, ant-fouling properties and mechanical strength were significantly improved when PPTA content was 17 wt%. When PPTA content increased to 26 wt%, membrane bursting pressure increased to nearly 0.6 MPa which was 1.5 times higher than that of PVDF membrane. The resultant PVDF/PPTA blend membrane exhibited an improved antifouling property than that of PVDF membrane when applied in the MBR in the

Physicochemical characteristics of guava “Paluma” submitted to osmotic dehydration

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Roselene Ferreira Oliveira

2014-09-01

Full Text Available The aim of this work was to evaluate the conservation post process osmotic of guava stored temperature at 5oC. Guava (Psidium guajava L., red variety “Paluma” minimally processed by mild osmotic dehydration, were packaged in polyethylene terephthalate (PET and stored temperature at 5ºC. Non-treated guava, packed in PET trays, was used as control. The treatment used was osmotic dehydration in sucrose syrup at 60ºBrix and physicochemical determinations were pH, total soluble solids (TSS, total titratable acidity (TTA, reducing sugars (RS, total sugars (TS and parameters related to colour read (a*, chroma (c*, yellow (b*, luminosity (L* of the fresh and osmotically dehydrated guava slices. The dehydrated fruits lost about 34.45% of water, concentrating contents of soluble solids, total and reducing sugars, when compared to control samples. The pH value remained around 3.76 for the OD fruits and 3.87 for the fresh fruits. The colour of the dehydrated fruits was more intense than the control samples’. The guava slices osmotic dehydration had 21 days of shelf life, showed physicochemical characteristics significantly superior to the control samples’, having a stable and high quality product as a result.

Ozone fumigation for safety and quality of wine grapes in postharvest dehydration.

Science.gov (United States)

Botondi, Rinaldo; De Sanctis, Federica; Moscatelli, Niccolò; Vettraino, Anna Maria; Catelli, Cesare; Mencarelli, Fabio

2015-12-01

This paper proposes postharvest ozone fumigation (as a method) to control microorganisms and evaluate the effect on polyphenols, anthocyanins, carotenoids and cell wall enzymes during the grape dehydration for wine production. Pignola grapes were ozone-treated (1.5 g/h) for 18 h (A=shock treatment), then dehydrated or ozone-treated (1.5 g/h) for 18 h and at 0.5 g/h for 4 h each day (B=long-term treatment) during dehydration. Treatment and dehydration were performed at 10 °C. No significant difference was found for total carotenoid, total phenolic and total anthocyanin contents after 18 h of O3 treatment. A significant decrease in phenolic and anthocyanin contents occurred during treatment B. Also carotenoids were affected by B ozone treatment. Pectin methylesterase (PME) and polygalacturonase (PG) activities were higher in A-treated grapes during dehydration. Finally, ozone reduced fungi and yeasts by 50%. Shock ozone fumigation (A treatment) before dehydration can be used to reduce the microbial count during dehydration without affecting polyphenol and carotenoid contents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Voluntary dehydration among elementary school children residing in a hot arid environment.

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Bar-David, Y; Urkin, J; Landau, D; Bar-David, Z; Pilpel, D

2009-10-01

Voluntary dehydration is a condition where humans do not drink appropriately in the presence of an adequate fluid supply. This may adversely affect their physical and intellectual performance. The present study aimed to describe the prevalence of voluntary dehydration among elementary school children of different ethnicities and countries of birth. Four hundred and twenty-nine elementary school children, aged 8-10 years, from four subpopulations (Israeli-born Jewish and Bedouin-Arab children, and immigrant children who recently arrived to Israel from Eastern Europe and from Ethiopia) were studied. The level of dehydration was determined by noontime urine osmolality, from samples taken over 1 week in mid-summer. Urine osmolality dehydrated group was that of Israeli-born Jewish children, whereas the Bedouin-Arab children were the least dehydrated. A high proportion of children who reside in a hot and arid environment were found to be in a state of moderate to severe dehydration. Bedouin ethnicity was associated with better hydration, whereas Israeli-born Jews were most severely dehydrated. Educational intervention programmes promoting water intake should start in early childhood and continue throughout life.

Thermodynamics of dehydration process of uranyl nitrate pentahydrate of thorium

International Nuclear Information System (INIS)

Khamidov, F.A.; Mirsaidov, I.U.; Nazarov, K.M.; Nasriddinov, S.K.; Badalov, A.B.

2010-01-01

Present article is devoted to thermodynamics of dehydration process of uranyl nitrate pentahydrate of thorium. The results of researches of dehydration process of uranyl nitrate pentahydrate of thorium Th(NO_3)_4·5H_2O were considered. The researches were carried out by means of tensimeter method with membrane zero-manometer under equilibrium conditions and at 300-450 K temperature ranges. The thermodynamic characteristics of dehydration process of initial crystalline hydrate was defined.

Weathering of natural uranyl oxide hydrates: Schoepite polytypes and dehydration effects

International Nuclear Information System (INIS)

Finch, R.J.; Miller, M.L.; Ewing, R.C.

1992-01-01

Partial dehydration of schoepite, UO 3 x2H 2 O, is reported to produce three discrete schoepite polytypes with characteristic unit cell parameters, but this has not been confirmed. The loss of structural water from the schoepite interlayer results in progressive modification to the structure; expansion parallel to schoepite cleavage planes, and extensive fracturing. Dehydration of schoepite commences at grain boundaries and progresses inward until the entire grain is converted to dehydrated schoepite, UO 3 x0.8H 2 O. The volume decrease associated with dehydration results in expanded grain boundaries. These gaps can provide pathways for the access of groundwater, and uranyl silicates and uranyl carbonates have precipitated within these gaps, replacing both schoepite and dehydrated schoepite. Schoepite, however, is not observed to re-precipitate where in contact with dehydrated schoepite. Thus, while the formation of schoepite early during the corrosion of uraninite may be favored, schoepite is not a long-term solubility limiting phase for oxidized uranium in natural ground waters containing dissolved silica or carbonate. (orig.)

Effect of friction on vibrotactile sensation of normal and dehydrated skin.

Science.gov (United States)

Chen, S; Ge, S; Tang, W; Zhang, J

2016-02-01

Vibrotactile sensation mediated is highly dependent on surface mechanical and frictional properties. Dehydration of skin could change these properties. To investigate the relationship between friction and vibrotactile sensation of normal and dehydrated skin. Vibrations were firstly measured during surface exploration using a biomimetic sensor. Piglet skin was used as human skin model to study frictional properties for both normal and dehydrated skin using an atomic force microscope on nanoscale and a pin-on-disk tribometer on macroscale. Effect of vibrational frequency on friction and vibrotactile perception was also observed on nano and macro scale for normal and dehydrated skin. The result indicated that dehydrated skin was less sensitive than normal skin. The coefficient of friction of dehydrated skin is smaller than that of normal skin on both nano and macro scale. The coefficient of friction increases as increasing scanning frequencies. There is a positive correlation between coefficient of friction and vibrotactile sensation on nanoscale and macroscale. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Intraocular pressure following 18 hours of systemic dehydration in ocular normotensive healthy subjects

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Faustina K. Idu

2015-07-01

Full Text Available Aim: To investigate the effect of dehydration on intraocular pressure (IOP. Subjects: The study population comprised 50 subjects (27 men and 23 women with a mean age of 42.84 ± 2.64 years. Method: The subjects dehydrated for 18 hours. IOP was assessed in both eyes using the Perkins handheld applanation tonometer. Baseline measurement of IOP was taken before the subjects dehydrated for 18 hours and repeated after dehydration. Blood samples were taken before and after dehydration for the determination of plasma osmolality and plasma antidiuretic hormone (ADH concentrations. Results: A statistically significant (p < 0.001 reduction in the mean weight of subjects occurred after dehydration. There was a significant reduction in IOP from 16.68 mmHg ± 0.32 mmHg to 13.08 mmHg ± 0.31 mmHg after dehydration (p < 0.001. Mean plasma osmolality showed a statistically significant increase (p < 0.05 from baseline of 290.02 mOsmol/kg ± 1.25 mOsmol/kg to 294.96 mOsmol/kg ± 1.33 mOsmol/kg after dehydration. There was also a significant increase (p < 0.05 in mean plasma ADH concentration from 5.36 pg/mL ± 0.21 pg/mL to 6.40 pg/mL ± 0.20 pg/mL after dehydration. There were no significant differences in both systolic and diastolic blood pressures before and after dehydration. Conclusion: Dehydration decreases IOP in healthy humans; this decrease probably results from an increase in plasma osmolality and plasma ADH concentrations.

Ethanol dehydration

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Ana María Uyazán

2004-09-01

Full Text Available This review outlines ethanol dehydration processes and their most important characteristics. It also deals with the main operating variables and some criteria used in designing the separation scheme. A differentiation is made between processes involving liquid steam balance in separation operations and those doing it by screening the difference in molecule size. The last part presents a comparison between the three main industrial processes, stressing their stengths and weaknesses from the operational, energy consumption and industrial services points of view.

Ultrasound assessment of severe dehydration in children with diarrhea and vomiting.

Science.gov (United States)

Levine, Adam C; Shah, Sachita P; Umulisa, Irenee; Munyaneza, Richard B Mark; Dushimiyimana, Jean Marie; Stegmann, Katrina; Musavuli, Juvenal; Ngabitsinze, Protogene; Stulac, Sara; Epino, Henry M; Noble, Vicki E

2010-10-01

The objective of this study was to determine the test characteristics for two different ultrasound (US) measures of severe dehydration in children (aorta to inferior vena cava [IVC] ratio and IVC inspiratory collapse) and one clinical measure of severe dehydration (the World Health Organization [WHO] dehydration scale). The authors enrolled a prospective cohort of children presenting with diarrhea and/or vomiting to three rural Rwandan hospitals. Children were assessed clinically using the WHO scale and then underwent US of the IVC by a second clinician. All children were weighed on admission and then fluid-resuscitated according to standard hospital protocols. A percent weight change between admission and discharge of greater than 10% was considered the criterion standard for severe dehydration. Receiver operating characteristic (ROC) curves were created for each of the three tests of severe dehydration compared to the criterion standard. Children ranged in age from 1 month to 10 years; 29% of the children had severe dehydration according to the criterion standard. Of the three different measures of dehydration tested, only US assessment of the aorta/IVC ratio had an area under the ROC curve statistically different from the reference line. At its best cut-point, the aorta/IVC ratio had a sensitivity of 93% and specificity of 59%, compared with 93% and 35% for IVC inspiratory collapse and 73% and 43% for the WHO scale. Ultrasound of the aorta/IVC ratio can be used to identify severe dehydration in children presenting with acute diarrhea and may be helpful in guiding clinical management. © 2010 by the Society for Academic Emergency Medicine.

40 CFR 407.50 - Applicability; description of the dehydrated potato products subcategory.

Science.gov (United States)

2010-07-01

... dehydrated potato products subcategory. 407.50 Section 407.50 Protection of Environment ENVIRONMENTAL... PROCESSING POINT SOURCE CATEGORY Dehydrated Potato Products Subcategory § 407.50 Applicability; description of the dehydrated potato products subcategory. The provisions of this subpart are applicable to...

Theoretical Study on Regioselectivity of the Diels-Alder Reaction between 1,8-Dichloroanthracene and Acrolein.

Science.gov (United States)

Sultan, Mujeeb A; Karama, Usama; Almansour, Abdulrahman I; Soliman, Saied M

2016-09-23

A theoretical study of the regioselectivity of the Diels-Alder reaction between 1,8-dichloroanthracene and acrolein is performed using DFT at the B3LYP/6-31G(d,p) level of theory. The FMO analysis, global and local reactivity indices confirmed the reported experimental results. Potential energy surface analysis showed that the cycloadditions (CAs) favor the formation of the anti product. These results are in good agreement with the reported results obtained experimentally where the anti is the major product.

Dehydration and rehydration of a tuff vitrophyre

International Nuclear Information System (INIS)

Vaniman, D.; Bish, D., Chipera, S.

1993-01-01

The basal vitrophyre of the Topopah Spring Member of the Paintbrush Tuff at Yucca Mountain, Nevada, is a perlitic glass with 2.8 to 4.6% water. The dehydration of this vitrophyre was studied by thermogravimetric analysis (TGA) and by isothermal heating at 50 degrees, 100 degrees, 200 degrees, and 400 degrees C for 3.4 years followed by 1.1 years of rehydration at high controlled humidity (∼79% relative humidity). No crystallization of the glass was observed in long-term dehydration or rehydration; the only observed chemical alteration was loss of up to 60% of original fluorine. TGA studies show a characteristic two-stage dehydration of the vitrophyre, with two-thirds to three-fourths weight loss occurring most rapidly at temperatures ranging from 278 degrees to 346 degrees C in 10 degrees C/min heating experiments. The remaining water, about 1% in all of the vitrophyre samples studied regardless of total water content, is lost only on second-stage heating to temperatures above 650 degrees C. Long-term isothermal heating at ≤400 degrees C releases only the first-stage water. Loss of essentially all first-stage water occurred in less than 1 hour at 400 degrees C; proportionately lower losses were obtained at 200 degrees and 100 degrees C. Small (0.2%) water loss occurred in the 50 degrees C experiment. A time-temperature-dehydration diagram generated from the isothermal heating data shows a clustering of dehydration contours that are the equilibrium equivalent of the rapid first-stage water loss in dynamic TGA experiments. These dry-heating experiments provide an end-member characterization of glass transformations for comparison with water-saturated heating experiments in which glass alteration is prominent. 29 figs., 7 figs., 7 tabs

Research on terahertz properties of rat brain tissue sections during dehydration

Science.gov (United States)

Cui, Gangqiang; Liang, Jianfeng; Zhao, Hongwei; Zhao, Xianghui; Chang, Chao

2018-01-01

Biological tissue sections are always kept in a system purged with dry nitrogen for the measurement of terahertz spectrum. However, the injected nitrogen will cause dehydration of tissue sections, which will affect the accuracy of spectrum measurement. In this paper, terahertz time-domain spectrometer is used to measure the terahertz spectra of rat brain tissue sections during dehydration. The changes of terahertz properties, including terahertz transmittance, refractive index and extinction coefficient during dehydration are also analyzed. The amplitudes of terahertz time-domain spectra increase gradually during the dehydration process. Besides, the terahertz properties show obvious changes during the dehydration process. All the results indicate that the injected dry nitrogen has a significant effect on the terahertz spectra and properties of tissue sections. This study contributes to further research and application of terahertz technology in biomedical field.

Regioselective 1,4- and 1,6-Conjugate Additions of Grignard Reagent-Derived Organozinc(II)ates to Polyconjugated Esters.

Science.gov (United States)

Hatano, Manabu; Mizuno, Mai; Ishihara, Kazuaki

2016-09-16

Regioselective synthetic methods were developed for 1,4- and 1,6-conjugate additions of Grignard reagent-derived organozinc(II)ates to malonate-derived polyconjugated esters. By taking advantage of the tight ion-pair control of organozinc(II)ates, it was possible to switch between 1,4- and 1,6-conjugate additions by introducing a terminal ethoxy moiety in the conjugation.

Effect of dioxan and toluene as solvents on: Polycondensation leading to poly (2.5-furylene vinylene)s

International Nuclear Information System (INIS)

Al-Hariri, S. N.

2008-01-01

This paper describes the influence of two different solvents, on a synthetic route leading to linear poly (2.5-furylene vinylene)s PFV, which involves the polycondensation of 5-methyl furfural in a basic medium, and on the characterization of PFV. The replacement of benzene by dioxan gives a linear polymeric structure possessing a high degree of conjugation, a good degree of polymerization, a remarkable stability to storage under ordinary condition and a partial solubility in common solvents, especially methylene chloride. Casting films from solution polymer gives brittle material, without any mechanical strength. However, the product obtained by using the toluene differs from the expected polymer. The results indicate that the raising of the degree of polymerization was done by increasing the time of reaction and successively introducing the monomer. Monomer, and dimer are isolated and characterized from the sub-product (oligomer) of the reaction. (author)

Dehydration kinetics of boehmite in the temperature range 723–873 K

International Nuclear Information System (INIS)

Xu, Bingan; Smith, Peter

2012-01-01

Highlights: ► The dehydration of boehmite is a complex topotactic process. ► The process is chemical control with a diffusion complication as the reaction progresses. ► Al cation diffusion is the rate-limiting step. ► The reaction rates predicted by the model-free method agree well with the measured values. - Abstract: The dehydration kinetics of boehmite prepared from the hydrothermal transformation of gibbsite has been comprehensively studied to clarify the mechanism of the dehydration process using a thermogravimetric technique under both isothermal and non-isothermal conditions. Selected residues were examined by XRD, SEM, TEM and selected area electron diffraction (SAED). Results indicate that the dehydration process is a topotactic reaction which brings about γ-Al 2 O 3 with porous microstructure and poor crystallinity. The kinetic data were analysed using the model-free (isoconversional) methods. The results indicate that the activation energy of the dehydration process depends on the reaction extent, signifying the dehydration process is chemical controlled with a diffusion complication as the reaction extent increases. Prediction of the dehydration extent was accomplished using the kinetic parameter of the non-isothermal process and the isoconversional method. The predicted rate is in a reasonably good agreement with the measured values. Finally the mechanism of the dehydration process is discussed based on the auxiliary results from the physical examination of the reacted residues and the kinetic behaviour.

Dehydration and fluid volume kinetics before major open abdominal surgery.

Science.gov (United States)

Hahn, R G; Bahlmann, H; Nilsson, L

2014-11-01

Assessment of dehydration in the preoperative setting is of potential clinical value. The present study uses urine analysis and plasma volume kinetics, which have both been validated against induced changes in body water in volunteers, to study the incidence and severity of dehydration before open abdominal surgery begins. Thirty patients (mean age 64 years) had their urine analysed before major elective open abdominal surgery for colour, specific weight, osmolality and creatinine. The results were scored and the mean taken to represent a 'dehydration index'. Thereafter, the patients received an infusion of 5 ml/kg of Ringer's acetate intravenously for over 15 min. Blood was sampled for 70 min and the blood haemoglobin concentration used to estimate the plasma volume kinetics. Distribution of fluid occurred more slowly (P dehydrated as compared with euhydrated patients. The dehydration index indicated that the fluid deficit in these patients corresponded to 2.5% of the body weight, whereas the deficit in the others was 1%. In contrast, the 11 patients who later developed postoperative nausea and vomiting had a very short elimination half-life, only 9 min (median, P dehydration before major surgery was modest as evidenced both by urine sampling and volume kinetic analysis. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Severe diarrhea-dehydration in infancy permanently alters auditory function.

Science.gov (United States)

Todd, N Wendell

2012-02-01

Of the myriad etiologies of sensorineural hearing impairment, metabolic stress is rarely considered. I posit that severe dehydration in conjunction with hypoxia, at least during infancy, prompts permanent changes in the cochlea. In a population-based prospective study of otitis media, children without otitis were found to have at age 4-8 years, worse auditory thresholds if as an infant had been hospitalized for diarrhea-dehydration. What is more, stapedius reflex thresholds tended to be lower in children who had been hospitalized for diarrhea-dehydration: that is, less acoustic energy for arousal or to be frightening. The hypothesis that the transient metabolic stress of dehydration with hypoxia prompts permanent sensorineural hearing impairment with reduced uncomfortable loudness thresholds, is both (1) consistent in an evolutionary sense with a subsequent survival advantage, and (2) subject to verification both by descriptive studies of children undergoing ECMO (ExtraCorporeal Membrane Oxygenation) or care for congenital diaphragmatic hernia, and by animal studies. Copyright © 2011 Elsevier Ltd. All rights reserved.

Comparison of clinical associations and laboratory abnormalities in children with moderate and severe dehydration.

Science.gov (United States)

Hayajneh, Wail A; Jdaitawi, Hussein; Al Shurman, Abdullah; Hayajneh, Yaseen A

2010-03-01

To search for possible early clinical associations and laboratory abnormalities in children with severe dehydration in northern Jordan. We prospectively evaluated 251 children with acute gastroenteritis. Dehydration assessment was done following a known clinical scheme. Probable clinical associations and laboratory abnormalities were examined against the preassigned dehydration status. Children with severe dehydration had significantly more hypernatremia and hyperkalemia, less isonatremia, and higher mean levels of urea, creatinine, and glucose (P dehydration. Historic clinical characteristics of patients did not correlate to dehydration degree. Serum urea, creatinine, sodium, potassium, and glucose were useful independently in augmenting clinical examination to diagnose the degree of dehydration status among children presenting with gastroenteritis. Serum urea performed the best among all. On the contrary, none of the examined historical clinical patterns could be correlated to the dehydration status. Larger and multicenter studies are needed to validate our results and to examine their impact on final outcomes.

Mathematical modeling of dehydration of 'Fuji' and 'Gala' apples slices using infrared

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Emílio de Souza Santos

2011-09-01

Full Text Available The objective of this work was to determine and model the infrared dehydration curves of apple slices - Fuji and Gala varieties. The slices were dehydrated until constant mass, in a prototype dryer with infrared heating source. The applied temperatures ranged from 50 to 100 °C. Due to the physical characteristics of the product, the dehydration curve was divided in two periods, constant and falling, separated by the critical moisture content. A linear model was used to describe the constant dehydration period. Empirical models traditionally used to model the drying behavior of agricultural products were fitted to the experimental data of the falling dehydration period. Critical moisture contents of 2.811 and 3.103 kgw kgs-1 were observed for the Fuji and Gala varieties, respectively. Based on the results, it was concluded that the constant dehydration rates presented a direct relationship with the temperature; thus, it was possible to fit a model that describes the moisture content variation in function of time and temperature. Among the tested models, which describe the falling dehydration period, the model proposed by Midilli presented the best fit for all studied conditions.

Dehydrated melon containing antioxidants and calcium from grape juice

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Hulda N. M. Chambi

2016-11-01

Full Text Available Background: Grape juice has a high antioxidant potential, capable of fighting oxidative processes in the body. The juice is mainly marketed in its concentrated form, which has a high content of glucose and fructose. The juice concentrate may then be used as an osmotic agent to dehydrated fruit with a relatively short shelf-life at room temperature, such as melon. The osmotic dehydration process can also be combined with conventional drying in order to further reduce the water activity (a w of the product. Finally, the antioxidant-rich melon meets the consumers’ demand for foods which contain ingredients that may impart health benefits. Results: Melon dehydrated by osmotic process at 200, 400 and 600 mbar, using grape juice concentrate (GJC, showed no significant differences in physical characteristics (a w , °Brix, and moisture content. Higher efficiency was observed when dehydration was performed at 200 mbar. After osmotic dehydration with GJC, both plasmolysis of the melon cells and an increase in intercellular spaces were observed by optical microscopy, with no negative impact on the mechanical properties (True stress, Hencky’s strain and deformability modulus. Calcium present in GJC was impregnated into the melon matrix, thus contributing with the mineral composition and mechanical properties of the final product. No significant differences were observed for the antioxidant capacity of melon dehydrated both with GJC and GJC followed by air-drying at 50 and 70°C. This demonstrates that it is possible to combine the two processes to obtain a product with intermediate moisture without decreasing its antioxidant capacity. The samples scored above the acceptable limit (>5 varying between like slightly to like moderately, resulting in a purchase intent with average scores between 3 (maybe/maybe not buy and 4 (probably would buy. Conclusions: A product with intermediate water activity, acidic, firm, high antioxidant capacity, rich in calcium

Asymmetric synthesis of allylic sulfonic acids: enantio- and regioselective iridium-catalyzed allylations of Na2SO3.

Science.gov (United States)

Liu, Wei; Zhao, Xiao-ming; Zhang, Hong-bo; Zhang, Liang; Zhao, Ming-zhu

2014-12-15

An enantioselective allylation reaction of allylic carbonates with sodium sulfite (Na2 SO3 ) catalyzed by Ir complex was accomplished, providing allylic sulfonic acids in good to excellent yields with a high level of enantio- and regioselectivities. (R)-2-Phenyl-2-sulfoacetic acid, a key intermediate for the synthesis of Cefsulodin and Sulbenicillin, was synthesized as well. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Organ specific proteomic dissection of Selaginella bryopteris undergoing dehydration and rehydration

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Farah eDeeba

2016-04-01

Full Text Available To explore molecular mechanisms underlying the physiological response of Selaginella bryopteris, a comprehensive proteome analysis was carried out in roots and fronds undergoing dehydration and rehydration. Plants were dehydrated for 7 days followed by 2 h and 24 h of rehydration. In roots out of 59 identified spots, 58 protein spots were found to be up-regulated during dehydration stress. The identified proteins were related to signaling, stress and defense, protein and nucleotide metabolism, carbohydrate and energy metabolism, storage and epigenetic control. Most of these proteins remained up-regulated on first rehydration, suggesting their role in recovery phase also. Among the 90 identified proteins in fronds, about 49% proteins were up-regulated during dehydration stress. Large number of ROS scavenging proteins was enhanced on dehydration. Many other proteins involved in energy, protein turnover and nucleotide metabolism, epigenetic control were also highly upregulated. Many photosynthesis related proteins were upregulated during stress. This would have helped plant to recover rapidly on rehydration. This study provides a comprehensive picture of different cellular responses elucidated by the proteome changes during dehydration and rehydration in roots and fronds as expected from a well-choreographed response from a resurrection plant.

Hospital Admissions for Malnutrition and Dehydration in Patients With Dementia.

Science.gov (United States)

Marshall, Katherine A; Burson, Rosanne; Gall, Kristyn; Saunders, Mitzi M

2016-01-01

Dehydration and malnutrition are commonly experienced by patients with dementia and can result in hospitalizations and decreased quality of life. The purpose of this study was to explore and describe retrospectively, the incidence and correlations of variables that may precede hospitalizations for dehydration/malnutrition in the community-dwelling patient with dementia. Data from the Outcome and Assessment Information Set (OASIS) Start of Care (SOC) on 44 patients served by a Michigan home care agency were retrieved for analysis. This study did not reveal any single or collection of variables that would predict risk for hospitalization for dehydration/malnutrition. With the lack of specific predictors of hospitalization related to dehydration and malnutrition, clinicians need to place high priority on risk-lowering strategies and preventive education for patients, family, and caregivers.

Thermal Dehydration Kinetics of Gypsum and Borogypsum under Non-isothermal Conditions

Institute of Scientific and Technical Information of China (English)

I.Y.Elbeyli; S.Piskin

2004-01-01

Thermal dehydration of gypsum and borogypsum was investigated under nonisothermal conditions in air by using simultaneous thermogravimetric-differential thermal analyzer. Nonisothermal experiments were carried out at various linear heating rates. Kinetics of dehydration in the temperature range of 373-503 K were evaluated from the DTA (differential thermal analysis)-TGA (thermogravimetric analysis) data by means of Coats-Redfern,Kissinger and Doyle Equations. Values of the activation energy and the pre-exponential factor of the dehydration were calculated. The results of thermal experiments and kinetic parameters indicated that borogypsum is similar to gypsum from dehydration mechanism point of view although it consists of boron and small amount of alkali metal oxides.

Control of regioselectivity over gold nanocrystals of different surfaces for the synthesis of 1,4-disubstituted triazole through the click reaction.

Science.gov (United States)

Rej, Sourav; Chanda, Kaushik; Chiu, Chun-Ya; Huang, Michael H

2014-11-24

Gold nanocubes, octahedra, and rhombic dodecahedra were examined for facet-dependent catalytic activity in the formation of triazoles. Rhombic dodecahedra gave 100% regioselective 1,4-triazoles. The product yield was increased by decreasing the particle size. However, a mixture of 1,4- and 1,5-triazoles was obtained in lower yields when cubes and octahedra of similar sizes were used. The lowest Au-atom density on the {110} surface and largest unsaturated coordination number of surface Au atoms may explain their best catalytic efficiency and product regioselectivity. Various spectroscopic techniques were employed to verify the formation of the Au-acetylide intermediate and establish the reaction mechanism, in which phenylacetylene binds to the Au {110} surface through the terminal-binding mode to result in the exclusive formation of 1,4-triazoles. The smallest rhombic dodecahedra can give diverse 1,4-disubstituted triazoles in good yields by coupling a wide variety of alkynes and organic halides. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theoretical Study on Regioselectivity of the Diels-Alder Reaction between 1,8-Dichloroanthracene and Acrolein

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Mujeeb A. Sultan

2016-09-01

Full Text Available A theoretical study of the regioselectivity of the Diels-Alder reaction between 1,8-dichloroanthracene and acrolein is performed using DFT at the B3LYP/6-31G(d,p level of theory. The FMO analysis, global and local reactivity indices confirmed the reported experimental results. Potential energy surface analysis showed that the cycloadditions (CAs favor the formation of the anti product. These results are in good agreement with the reported results obtained experimentally where the anti is the major product.

Stereo- and regioselectivity of the hetero-Diels-Alder reaction of nitroso derivatives with conjugated dienes.

Science.gov (United States)

Brulíková, Lucie; Harrison, Aidan; Miller, Marvin J; Hlaváč, Jan

2016-01-01

The hetero-Diels-Alder reaction between a nitroso dienophile and a conjugated diene to give the 3,6-dihydro-2 H -1,2-oxazine scaffold is useful for the synthesis of many biologically interesting molecules due to the diverse opportunities created by subsequent transformations of the resulting 1,2-oxazine ring. This review discusses the rationale for the observed regio- and stereoselectivity and the methods developed in recent years used to control and improve the stereo- and regioselectivity for the synthesis of 1,2-oxazine scaffolds.

Dehydration of δ-AlOOH in the lower mantle

Science.gov (United States)

Piet, H.; Shim, S. H.; Tappan, J.; Leinenweber, K. D.; Greenberg, E.; Prakapenka, V. B.

2017-12-01

Hydrous phase δ-AlOOH is an important candidate for water transport and storage in the Earth's deep mantle [1]. Knowing the conditions, under which it is stable and dehydrated, is therefore important for understanding the water transportation to the deep mantle or even to the core. A few experimental studies [1, 2] have shown that δ-AlOOH may be stable in cold descending slabs while it is dehydrated into a mixture of corundum and water under normal mantle conditions, up to 25 GPa. A subsequent study [3] reported the stability of δ-AlOOH in cold descending slabs to the core-mantle boundary conditions (2300 K at 135 GPa). However, the dehydration of δ-AlOOH has not bee directly observed in the experiments conducted at pressures above 25 GPa. We have synthesized δ-AlOOH from diaspore and Al(OH)3 in multi-anvil press at ASU. The sample was mixed with Au for coupling with near IR laser beams and loaded in diamond-anvil cells. We performed the laser-heated diamond anvil cell experiments at the 13IDD beamline of the Advanced Photon Source and ASU. At APS, we measured X-ray diffraction patterns at in situ high pressure and temperature. We observed the appearance of the corundum diffraction lines at 1700-2000 K and 55-90 GPa, indicating the dehydration of δ-AlOOH to Al2O3+ H2O. We found that the transition occurs over a broad range of temperature (500 K). We also observed that the dehydration of δ-AlOOH was accompanied by sudden change in laser coupling, most likely due to the release of fluids. The property change also helps us to determine the dehydration at ASU without in situ XRD. Our new experimental results indicate that δ-AlOOH would be stable in most subducting slabs in the deep mantle. However, because the dehydration occurs very close to the temperatures expected for the lower mantle, its stability is uncertain in the normal mantle. [1] Ohtani et al. 2001, Stability field of new hydrous phase, delta-AlOOH, Geophysical Research Letters 28, 3991-3993. [2

Ibuprofen-associated acute kidney injury in dehydrated children with acute gastroenteritis.

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Balestracci, Alejandro; Ezquer, Mauricio; Elmo, María Eugenia; Molini, Andrea; Thorel, Claudia; Torrents, Milagros; Toledo, Ismael

2015-10-01

Non-steroidal anti-inflammatory drugs (NSAIDs) induce acute kidney injury (AKI) in volume-depleted patients; however the prevalence of this complication is likely underestimated. We assessed the impact of ibuprofen exposure on renal function among dehydrated children with acute gastroenteritis (AGE) to further characterize NSAID-associated AKI. Over a 1-year period dehydrated children with AGE (n = 105) were prospectively enrolled and grouped as cases, presenting with AKI (n = 46) or controls, not presenting with AKI (n = 59). AKI was defined by pediatric RIFLE (pRIFLE) criteria. Among the children enrolled in the study, AKI prevalence was 44 %, and 34 (54 %) of the 63 patients who received ibuprofen developed renal impairment. Relative to the controls, children presenting with AKI were younger (median age 0.66 vs. 1.74 years; p dehydration, ibuprofen exposure remained an independent risk factor for AKI (p dehydrated children with AGE. Drug exposure increased the risk for developing AKI by more than twofold, independent of the magnitude of the dehydration.

Study of Trehalose Addition on Aroma Retention in Dehydrated Strawberry Puree

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Draženka Komes

2003-01-01

Full Text Available In order to improve the quality of dehydrated fruit products, the influence of the addition of two sugars (sucrose and trehalose on the retention of aroma components during dehydration of strawberry puree was investigated. Manual headspace solid-phase microextraction (SPME, containing polydimethylsiloxane coated fibre (100 μm coupled with gas chromatography (GC-FID and GC-MS was used for the analysis of the aroma of strawberry puree dehydrated by using freeze drying and foam-mat drying. The analytes identified included esters, carbonyl compounds, terpenoids, several alcohols and acids. The results obtained in this study give further insight into the mechanisms concerning the application of trehalose as flavouring additive, due to its ability to retain and preserve the fruit volatiles responsible for the characteristic flavour of fresh fruits during dehydration processes. The best retention of aroma components in dehydrated strawberry puree was obtained by trehalose addition when combined with freeze drying.

Enzyme-Catalyzed Regioselective Modification of Starch Nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chakraborty, Soma [Polytechnic Univ., Brooklyn, NY (United States). National Science Foundation (NSF) Center for Biocatalysis and Bioprocessing of Macromolecules, Othmer Dept. of Chemical and Biological Science and Engineering; Sahoo, Bishwabhusan [Polytechnic Univ., Brooklyn, NY (United States). National Science Foundation (NSF) Center for Biocatalysis and Bioprocessing of Macromolecules, Othmer Dept. of Chemical and Biological Science and Engineering; Teraoka, Iwao [Polytechnic Univ., Brooklyn, NY (United States). National Science Foundation (NSF) Center for Biocatalysis and Bioprocessing of Macromolecules, Othmer Dept. of Chemical and Biological Science and Engineering; Miller, Lisa M. [Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source (NSLS); Gross, Richard A. [Polytechnic Univ., Brooklyn, NY (United States). National Science Foundation (NSF) Center for Biocatalysis and Bioprocessing of Macromolecules, Othmer Dept. of Chemical and Biological Science and Engineering

2004-12-13

The selective esterification of starch nanoparticles was performed using as catalyst Candida antartica Lipase B (CAL-B) in its immobilized (Novozym 435) and free (SP-525) forms. The starch nanoparticles were made accessible for acylation reactions by formation of Aerosol-OT (AOT, bis(2-ethylhexyl)sodium sulfosuccinate) stabilized microemulsions. Starch nanoparticles in microemulsions were reacted with vinyl stearate, ε-caprolactone, and maleic anhydride at 40 °C for 48 h to give starch esters with degrees of substitution (DS) of 0.8, 0.6, and 0.4, respectively. Substitution occurred regioselectively at the C-6 position of the glucose repeat units. Infrared microspectroscopy (IRMS) revealed that AOT-coated starch nanoparticles diffuse into the outer 50 μm shell of catalyst beads. Thus, even though CAL-B is immobilized within a macroporous resin, CAL-B is sufficiently accessible to the starch nanoparticles. When free CAL-B was incorporated along with starch within AOT-coated reversed micelles, CAL-B was also active and catalyzed the acylation with vinyl stearate (24 h, 40 °C) to give DS = 0.5. After removal of surfactant from the modified starch nanoparticles, they were dispersed in DMSO or water and were shown to retain their nanodimensions.

Dehydration triggers differential microRNA expression in Xenopus laevis brain.

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Luu, Bryan E; Storey, Kenneth B

2015-11-15

African clawed frogs, Xenopus laevis, although primarily aquatic, have a high tolerance for dehydration, being capable of withstanding the loss of up to 32-35% of total water body water. Recent studies have shown that microRNAs play a role in the response to dehydration by the liver, kidney and ventral skin of X. laevis. MicroRNAs act by modulating the expression of mRNA transcripts, thereby affecting diverse biochemical pathways. In this study, 43 microRNAs were assessed in frog brains comparing control and dehydrated (31.2±0.83% of total body water lost) conditions. MicroRNAs of interest were measured using a modified protocol which employs polyadenylation of microRNAs prior to reverse transcription and qPCR. Twelve microRNAs that showed a significant decrease in expression (to 41-77% of control levels) in brains from dehydrated frogs (xla-miR-15a, -150, -181a, -191, -211, -218, -219b, -30c, -30e, -31, -34a, and -34b) were identified. Genomic analysis showed that the sequences of these dehydration-responsive microRNAs were highly conserved as compared with the comparable microRNAs of mice (91-100%). Suppression of these microRNAs implies that translation of the mRNA transcripts under their control could be enhanced in response to dehydration. Bioinformatic analysis using the DIANA miRPath program (v.2.0) predicted the top two KEGG pathways that these microRNAs collectively regulate: 1. Axon guidance, and 2. Long-term potentiation. Previous studies indicated that suppression of these microRNAs promotes neuroprotective pathways by increasing the expression of brain-derived neurotrophic factor and activating anti-apoptotic pathways. This suggests that similar actions may be triggered in X. laevis brains as a protective response to dehydration. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Phase transitions on dehydration of the natural zeolite thomsonite

DEFF Research Database (Denmark)

Ståhl, Kenny

2001-01-01

The dehydration of the natural zeolite thomsonite, Na4CasAl20Si20O80 24H(2)O, has been studied using a combination of conventional and synchrotron X-ray powder diffraction. A preliminary in situ dehydration study revealed two distinct unit cell changes at approximately 540 and 570 K, respectively...

Straightforward uranium-catalyzed dehydration of primary amides to nitriles

International Nuclear Information System (INIS)

Enthaler, Stephan

2011-01-01

The efficient uranium-catalyzed dehydration of a variety of primary amides, using N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) as a dehydration reagent, to the corresponding nitriles has been investigated. With this catalyst system, extraordinary catalyst activities and selectivities were feasible. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Bioactivation and Regioselectivity of Pig Cytochrome P450 3A29 towards Aflatoxin B1

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Jun Wu

2016-09-01

Full Text Available Due to unavoidable contaminations in feedstuff, pigs are easily exposed to aflatoxin B1 (AFB1 and suffer from poisoning, thus the poisoned products potentially affect human health. Heretofore, the metabolic process of AFB1 in pigs remains to be clarified, especially the principal cytochrome P450 oxidases responsible for its activation. In this study, we cloned CYP3A29 from pig liver and expressed it in Escherichia coli, and its activity has been confirmed with the typical P450 CO-reduced spectral characteristic and nifedipine-oxidizing activity. The reconstituted membrane incubation proved that the recombinant CYP3A29 was able to oxidize AFB1 to form AFB1-exo-8,9-epoxide in vitro. The structural basis for the regioselective epoxidation of AFB1 by CYP3A29 was further addressed. The T309A mutation significantly decreased the production of AFBO, whereas F304A exhibited an enhanced activation towards AFB1. In agreement with the mutagenesis study, the molecular docking simulation suggested that Thr309 played a significant role in stabilization of AFB1 binding in the active center through a hydrogen bond. In addition, the bulk phenyl group of Phe304 potentially imposed steric hindrance on the binding of AFB1. Our study demonstrates the bioactivation of pig CYP3A29 towards AFB1 in vitro, and provides the insight for understanding regioselectivity of CYP3A29 to AFB1.

Proteome analysis of Physcomitrella patens exposed to progressive dehydration and rehydration

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Cui, Suxia; Hu, Jia; Guo, Shilei; Wang, Jie; Cheng, Yali; Dang, Xinxing; Wu, Lili; He, Yikun

2012-01-01

Physcomitrella patens is an extremely dehydration-tolerant moss. However, the molecular basis of its responses to loss of cellular water remains unclear. A comprehensive proteomic analysis of dehydration- and rehydration-responsive proteins has been conducted using quantitative two-dimensional difference in-gel electrophoresis (2D-DIGE), and traditional 2-D gel electrophoresis (2-DE) combined with MALDI TOF/TOF MS. Of the 216 differentially-expressed protein spots, 112 and 104 were dehydration- and rehydration-responsive proteins, respectively. The functional categories of the most differentially-expressed proteins were seed maturation, defence, protein synthesis and quality control, and energy production. Strikingly, most of the late embryogenesis abundant (LEA) proteins were expressed at a basal level under control conditions and their synthesis was strongly enhanced by dehydration, a pattern that was confirmed by RT-PCR. Actinoporins, phosphatidylethanolamine-binding protein, arabinogalactan protein, and phospholipase are the likely dominant players in the defence system. In addition, 24 proteins of unknown function were identified as novel dehydration- or rehydration-responsive proteins. Our data indicate that Physcomitrella adopts a rapid protein response mechanism to cope with dehydration in its leafy-shoot and basal expression levels of desiccation-tolerant proteins are rapidly upgraded at high levels under stress. This mechanism appears similar to that seen in angiosperm seeds. PMID:21994173

Unveiling of novel regio-selective fatty acid double bond hydratases from Lactobacillus acidophilus involved in the selective oxyfunctionalization of mono- and di-hydroxy fatty acids.

Science.gov (United States)

Kim, Kyoung-Rok; Oh, Hye-Jin; Park, Chul-Soon; Hong, Seung-Hye; Park, Ji-Young; Oh, Deok-Kun

2015-11-01

The aim of this study is the first time demonstration of cis-12 regio-selective linoleate double-bond hydratase. Hydroxylation of fatty acids, abundant feedstock in nature, is an emerging alternative route for many petroleum replaceable products thorough hydroxy fatty acids, carboxylic acids, and lactones. However, chemical route for selective hydroxylation is still quite challenging owing to low selectivity and many environmental concerns. Hydroxylation of fatty acids by hydroxy fatty acid forming enzymes is an important route for selective biocatalytic oxyfunctionalization of fatty acids. Therefore, novel fatty acid hydroxylation enzymes should be discovered. The two hydratase genes of Lactobacillus acidophilus were identified by genomic analysis, and the expressed two recombinant hydratases were identified as cis-9 and cis-12 double-bond selective linoleate hydratases by in vitro functional validation, including the identification of products and the determination of regio-selectivity, substrate specificity, and kinetic parameters. The two different linoleate hydratases were the involved enzymes in the 10,13-dihydroxyoctadecanoic acid biosynthesis. Linoleate 13-hydratase (LHT-13) selectively converted 10 mM linoleic acid to 13S-hydroxy-9(Z)-octadecenoic acid with high titer (8.1 mM) and yield (81%). Our study will expand knowledge for microbial fatty acid-hydroxylation enzymes and facilitate the designed production of the regio-selective hydroxy fatty acids for useful chemicals from polyunsaturated fatty acid feedstocks. © 2015 Wiley Periodicals, Inc.

Economic burden associated with hospital postadmission dehydration.

Science.gov (United States)

Pash, Elizabeth; Parikh, Niraj; Hashemi, Lobat

2014-11-01

Development of dehydration after hospital admission can be a measure of quality care, but evidence describing the incidence, economic burden, and outcomes of dehydration in hospitalized patients is lacking. The objective of this study was to compare costs and resource utilization of U.S. patients experiencing postadmission dehydration (PAD) with those who do not in a hospital setting. All adult inpatient discharges, excluding those with suspected dehydration present on admission (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes for dehydration: 276.0, 276.1, 276.5), were identified from the Premier database using ICD-9-CM codes. PAD and no-PAD (NPAD) groups were matched on propensity score adjusting for demographics (age, sex, race, medical, elective patients), patient severity (All Patient Refined Diagnosis-Related Groups severity scores), and hospital characteristics (geographic location, bed size, teaching and urban hospital). Costs, length of stay (LOS), and incidence of mortality and catheter-associated urinary tract infection (CAUTI) were compared between groups using the t test for continuous variables and the χ(2) test for categorical variables. In total, 86,398 (2.1%) of all the selected patients experienced PAD. Postmatching mean total costs were significantly higher for the PAD group compared with the NPAD group ($33,945 vs $22,380; P < .0001). Departmental costs were also significantly higher for the PAD group (all P < .0001). Compared with the NPAD group, the PAD group had a higher mean LOS (12.9 vs 8.2 days), a higher incidence of CAUTI (0.6% vs 0.5%), and higher in-hospital mortality (8.6% vs 7.8%) (all P < .05). The results for subgroup analysis also showed significantly higher total cost and longer LOS days for patients with PAD (all P < .05). The economic burden associated with hospital PAD in medical and surgical patients was substantial. © 2014 American Society for Parenteral and Enteral

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

Directory of Open Access Journals (Sweden)

Lucie Brulíková

2016-09-01

Full Text Available The hetero-Diels–Alder reaction between a nitroso dienophile and a conjugated diene to give the 3,6-dihydro-2H-1,2-oxazine scaffold is useful for the synthesis of many biologically interesting molecules due to the diverse opportunities created by subsequent transformations of the resulting 1,2-oxazine ring. This review discusses the rationale for the observed regio- and stereoselectivity and the methods developed in recent years used to control and improve the stereo- and regioselectivity for the synthesis of 1,2-oxazine scaffolds.

Predictable and Regioselective Insertion of Internal Unsymmetrical Alkynes in Rhodium-Catalyzed Cycloadditions with Alkenyl Isocyanates

Science.gov (United States)

Friedman, Rebecca Keller; Rovis, Tomislav

2009-01-01

A regioselective, rhodium-catalyzed cycloaddition between a variety of internal, unsymmetrical alkynes is described. We document the impact of both steric and electronic properties of the alkyne on reaction course, efficiency and enantioselectivity. The substituent that better stabilizes a positive charge or the larger group, all else being equal, inserts distal to the carbonyl moiety in a predictable and controllable fashion. The reaction scope is broad and the enantioselectivities are high, providing an ‘instruction manual’ for substrate choice when utilizing this reaction as a synthetic tool. PMID:19569692

Combining Eosin Y with Selectfluor: A Regioselective Brominating System for Para-Bromination of Aniline Derivatives.

Science.gov (United States)

Huang, Binbin; Zhao, Yating; Yang, Chao; Gao, Yuan; Xia, Wujiong

2017-07-21

A mild, metal-free, and absolutely para-selective bromination of aniline derivatives has been developed in excellent yields, wherein the organic dye Eosin Y is employed as the bromine source in company with Selectfluor. Neither air nor moisture sensitive, this facile reaction proceeds smoothly at room temperature and completes within a short time. Mechanistic studies indicate a radical pathway; therefore, the existence of an in situ generated brominating reagent, "Selectbrom", is postulated, which may reasonably account for the unique regioselectivity for the para-bromination of N-acyl- as well as N-sulfonylanilines.

Quantitative Study for the Surface Dehydration of Vocal Folds Based on High-Speed Imaging.

Science.gov (United States)

Li, Lin; Zhang, Yu; Maytag, Allison L; Jiang, Jack J

2015-07-01

From the perspective of the glottal area and mucosal wave, quantitatively estimate the differences of vocal fold on laryngeal activity during phonation at three different dehydration levels. Controlled three sets of tests. A dehydration experiment for 10 excised canine larynges was conducted at 16 cm H2O. According to the dehydration cycle time (H), dehydration levels were divided into three degrees (0% H, 50% H, 75% H). The glottal area and mucosal wave under three dehydration levels were extracted from high-speed images and digital videokymography (DKG) image sequences. Direct and non-direct amplitude components were derived from glottal areas. The amplitude and frequency of mucosal wave were calculated from DKG image sequences. These parameters in condition of three dehydration levels were compared for statistical analysis. The results showed a significant difference in direct (P = 0.001; P = 0.005) and non-direct (P = 0.005; P = 0.016) components of glottal areas between every two different dehydration levels. Considering the right-upper, right-lower, left-upper, and left-lower of vocal fold, the amplitudes of mucosal waves consistently decreased with increasing of dehydration levels. But, there was no significant difference in frequency. Surface dehydration could give rise to complex variation of vocal fold on tissues and vibratory mechanism, which should need analyzing from multiple perspectives. The results suggested that the combination of glottal area and mucosal wave could be better to research the change of vocal fold at different dehydrations. It would become a better crucial research tool for the clinical treatment of dehydration-induced laryngeal pathologies. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Could Neonatal Hypernatremia Dehydration Influence Hearing Status?

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Hassan Boskabadi

2014-01-01

Full Text Available Introduction: Neonatal hypernatremia dehydration (NHD is a dangerous condition in neonates, which is accompanied by acute complications (renal failure, cerebral edema, and cerebral hemorrhage and chronic complications (developmental delay. Children begin learning language from birth, and hearing impairment interferes with this process. We assessed the hearing status of infants with hypernatremia dehydration.   Materials and Methods: In a case-control study in 110 infants presenting at the Ghaem Hospital (Mashhad, Iran between 2007 and 2011, we examined the incidence of hearing impairment in infants suffering from hypernatremia dehydration (serum sodium >150 mEq/L in comparison with infants with normal sodium level (serum sodium ≤150 mEq/L.   Results: Three of 110 cases examined in the study group showed a transient hearing impairment. A mean serum sodium level of 173mg/dl was reported among hearing-impaired infants.   Conclusion:  Transient hearing impairment was higher in infants with hypernatremia; although this difference was not significant (P>0.05. Hearing impairment was observed in cases of severe hypernatremia.  

Quality of frozen fruit bars manufactured through infrared pre-dehydration

Science.gov (United States)

In this study, frozen restructured whole apple and strawberry bars were manufactured by partial dehydration, using infrared (IR) heating, followed by restructuring and freezing. The objective of this investigation was to determine the effect of IR partial dehydration on the quality of restructured f...

Effects of tissue fixation and dehydration on tendon collagen nanostructure.

Science.gov (United States)

Turunen, Mikael J; Khayyeri, Hanifeh; Guizar-Sicairos, Manuel; Isaksson, Hanna

2017-09-01

Collagen is the most prominent protein in biological tissues. Tissue fixation is often required for preservation or sectioning of the tissue. This may affect collagen nanostructure and potentially provide incorrect information when analyzed after fixation. We aimed to unravel the effect of 1) ethanol and formalin fixation and 2) 24h air-dehydration on the organization and structure of collagen fibers at the nano-scale using small and wide angle X-ray scattering. Samples were divided into 4 groups: ethanol fixed, formalin fixed, and two untreated sample groups. Samples were allowed to air-dehydrate in handmade Kapton pockets during the measurements (24h) except for one untreated group. Ethanol fixation affected the collagen organization and nanostructure substantially and during 24h of dehydration dramatic changes were evident. Formalin fixation had minor effects on the collagen organization but after 12h of air-dehydration the spatial variation increased substantially, not evident in the untreated samples. Generally, collagen shrinkage and loss of alignment was evident in all samples during 24h of dehydration but the changes were subtle in all groups except the ethanol fixed samples. This study shows that tissue fixation needs to be chosen carefully in order to preserve the features of interest in the tissue. Copyright © 2017 Elsevier Inc. All rights reserved.

Preoperative dehydration increases risk of postoperative acute renal failure in colon and rectal surgery.

Science.gov (United States)

Moghadamyeghaneh, Zhobin; Phelan, Michael J; Carmichael, Joseph C; Mills, Steven D; Pigazzi, Alessio; Nguyen, Ninh T; Stamos, Michael J

2014-12-01

There is limited data regarding the effects of preoperative dehydration on postoperative renal function. We sought to identify associations between hydration status before operation and postoperative acute renal failure (ARF) in patients undergoing colorectal resection. The NSQIP database was used to examine the data of patients undergoing colorectal resection from 2005 to 2011. We used preoperative blood urea nitrogen (BUN)/creatinine ratio >20 as a marker of relative dehydration. Multivariate analysis using logistic regression was performed to quantify the association of BUN/Cr ratio with ARF. We sampled 27,860 patients who underwent colorectal resection. Patients with dehydration had higher risk of ARF compared to patients with BUN/Cr Dehydration was associated with an increase in mortality of the affected patients (AOR, 2.19; P dehydrated patients. Open colorectal procedures (AOR, 2.67; P = 0.01) and total colectomy procedure (AOR, 1.62; P Dehydration before operation is a common condition in colorectal surgery (incidence of 27.7 %). Preoperative dehydration is associated with increased rates of postoperative ARF, MI, and cardiac arrest. Hydrotherapy of patients with dehydration may decrease postoperative complications in colorectal surgery.

WATER TEMPERATURE, VOLUNTARY DRINKING AND FLUID BALANCE IN DEHYDRATED TAEKWONDO ATHLETES

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Saeed Khamnei

2011-12-01

Full Text Available Voluntary drinking is one of the major determiners of rehydration, especially as regards exercise or workout in the heat. The present study undertakes to search for the effect of voluntary intake of water with different temperatures on fluid balance in Taekwondo athletes. Six young healthy male Taekwondo athletes were dehydrated by moderate exercise in a chamber with ambient temperature at 38-40°C and relative humidity between 20-30%. On four separate days they were allowed to drink ad libitum plane water with the four temperatures of 5, 16, 26, and 58°C, after dehydration. The volume of voluntary drinking and weight change was measured; then the primary percentage of dehydration, sweat loss, fluid deficit and involuntary dehydration were calculated. Voluntary drinking of water proved to be statistically different in the presented temperatures. Water at 16°C involved the greatest intake, while fluid deficit and involuntary dehydration were the lowest. Intake of water in the 5°C trial significantly correlated with the subject's plasma osmolality change after dehydration, yet it showed no significant correlation with weight loss. In conclusion, by way of achieving more voluntary intake of water and better fluid state, recommending cool water (~16°C for athletes is in order. Unlike the publicly held view, drinking cold water (~5°C does not improve voluntary drinking and hydration status.

RANCANG BANGUN ALAT DEHYDRATOR BIOETANOL UNTUK MENGHASILKAN FUEL GRADE ETHANOL (FGE

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Rochmad Winarso

2015-11-01

Full Text Available ABSTRAK Bioethanol merupakan salah satu bahan bakar alternatif dengan sumber bahan baru yang dapat diperbarui. Bioethanol dapat menjadi bahan bakar alternatif bila mempunyai konsentrasi lebih dari 99% yang dikenal dengan nama Fuel Grade Ethanol. Proses pembuatan Fuel Grade Ethanol menggunakan metode pemisahan lanjut diantaranya adalah dengan metode distilasi azeotrop, pervorasi membran, dan adsorbsi. Tujuan dari penelitian ini adalah melakukan pengujian mesin dehydrator bioethanol yang bekerja dengan metode absorbsi. Mesin dehydrator ini menggunakan zeolit syntetis dengan ukuran 3 A yang sebelumnya telah dikembangkan. Pengembangan ini dilakukan melalui tiga tahapan, yaitu: (1 Tahap perancangan (desain alat dehydrator biorthanol; (2 Tahap pembuatan alat dehydrator berdasarkan spesifikasi yang telah ditetapkan ; (3 Pengujian alat dehydrator yang berorientasi hasil yaitu bioetanol minimal berkadar sekitar 99%. Mesin destilator bioetanol yang telah dikembangkan mempunya spesifikasi sebagai berikut: dimensi tangki bahan baku tingginya adalah 250 mm dengan diameter 300 mm, Bagian tabung I terbuat dari pipa stainless steel dengan diameter 100 mm dan tinggi 600 mm. Tebal dari pipa tersebut adalah 2 mm. Tabung II terbuat dari stainless steel yang mempunyai diamater 100 mm dan tinggi 300 mm dengan ketebalan 2 mm. Kondensor berdiameter 100 mm dan tinggi 600 mm. Hasil penelitian ini menunjukkan bahwa mesin yang sudah dikembangkan ini mampu menghasilkan Fuel Grade Ethanol dengan kadar lebih dari 99%. Kata kunci: dehydrator, bioethanol, fuel grade ethanol, bahan bakar alternatif.

(1)H nuclear magnetic resonance (NMR) as a tool to measure dehydration in mice.

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Li, Matthew; Vassiliou, Christophoros C; Colucci, Lina A; Cima, Michael J

2015-08-01

Dehydration is a prevalent pathology, where loss of bodily water can result in variable symptoms. Symptoms can range from simple thirst to dire scenarios involving loss of consciousness. Clinical methods exist that assess dehydration from qualitative weight changes to more quantitative osmolality measurements. These methods are imprecise, invasive, and/or easily confounded, despite being practiced clinically. We investigate a non-invasive, non-imaging (1)H NMR method of assessing dehydration that attempts to address issues with existing clinical methods. Dehydration was achieved by exposing mice (n = 16) to a thermally elevated environment (37 °C) for up to 7.5 h (0.11-13% weight loss). Whole body NMR measurements were made using a Bruker LF50 BCA-Analyzer before and after dehydration. Physical lean tissue, adipose, and free water compartment approximations had NMR values extracted from relaxation data through a multi-exponential fitting method. Changes in before/after NMR values were compared with clinically practiced metrics of weight loss (percent dehydration) as well as blood and urine osmolality. A linear correlation between tissue relaxometry and both animal percent dehydration and urine osmolality was observed in lean tissue, but not adipose or free fluids. Calculated R(2) values for percent dehydration were 0.8619 (lean, P dehydration in live animals. Copyright © 2015 John Wiley & Sons, Ltd.

Time-resolved x-ray diffraction analysis of the experimental dehydration of serpentine at high pressure

International Nuclear Information System (INIS)

Inoue, Toru; Yoshimi, Isamu; Yamada, Akihiro; Kikegawa, Takumi

2009-01-01

Time-resolved, in situ X-ray diffraction analysis was used to determine the dehydration rate and kinetics of serpentine during experimental dehydration at high pressures. The capsule used comprises a diamond sleeve fitted with Au or Pt lids in order to provide high-quality, time-resolved X-ray diffraction data. Antigorite quickly dehydrated to enstatite + forsterite + fluid within 2 h at 650degC below ∼6 GPa. Avrami modeling of the results and SEM observations of the partially dehydrated sample revealed that the nucleation rate was quite high for enstatite but low for forsterite, showing incubation periods of ∼10 min before appearing. The crystallization of these minerals is controlled largely by the composition of the fluid generated from serpentine dehydration. The dehydration boundary determined below 6 GPa in the present study is consistent with the results of previous phase equilibrium studies. This study indicates that serpentine in a subducting slab dehydrates rapidly below 6 GPa when the slab intersects the dehydration boundary conditions. (author)

Association Between Dehydration and Fever During the First Week of Life.

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Boutin, Ariane; Carceller, Ana; Desjardins, Marie Pier; Sanchez, Marisol; Gravel, Jocelyn

2017-12-01

Trying to differentiate serious bacterial infection (SBI) from a self-limiting illness in febrile infants seen in the pediatric emergency department (PED) is a significant challenge. The aim of the study was to determine the prevalence of dehydration and its relationship to SBI in febrile full-term newborns under 1 week of age seen in a PED. A retrospective observational study was carried out on all children younger than 8 days of age with fever who presented to a single, tertiary care, PED from January 2009 to April 2014. Dehydration was defined as plasma sodium >150 mmol/L or >10% loss of birth weight. SBI was defined by the presence of a positive culture in the blood, urine, cerebrospinal fluid; osteoarticular infection; bacterial enteritis; or pneumonia. The primary analysis was the proportion of children with dehydration. A secondary analysis compared proportion of infection according to hydration status. Of the 895 children under 8 days of age who visited the PED, 69 consulted for fever. Seven patients were excluded because they were transferred from another hospital. Sixty-two eligible patients were included in the final analysis. Of these, 17 (27%) were dehydrated according to our definition. Only 2 patients had an SBI while 2 others had a final diagnosis of viral myocarditis and encephalitis, respectively. None of the 4 children with serious infection fulfilled our definition of dehydration, and all had a plasma sodium level lower than 145 mmol/L. Dehydration is frequently associated with fever in infants younger than 8 days of age seen in a PED. Early identification of dehydration may be useful in limiting the aggressive intervention in some of these infants.

Studying thermal dehydration of double nickel alkali metal pyrophosphates

International Nuclear Information System (INIS)

Bykanova, T.A.; Lavrov, A.V.; AN SSSR, Moscow. Inst. Obshchej i Neorganicheskoj Khimii)

1978-01-01

The methods of thermogravimetry, paper chromatography, infrared spectroscopy and X-ray phase analysis were used in studying the process of thermal dehydration of pyrophosphates of the M 2 Ni 3 (P 2 O 7 ) 2 xnH 2 O type (where n=6, 10; M=Na, K, Rb, Cs, NH 4 ). The dehydration of Cs 2 Ni 3 (P 2 O 7 ) 2 x10H 2 O proceeds in a single stage (endothermal effect at 210 deg C). The exothermal effects at 730 and 690 deg C correspond to the crystallization of the amorphous dehydration products. It has been established that binary pyrophosphates of nickel with alkali metals decompose when heated into Ni 3 (PO 4 ) 2 +MPO 4

Dehydration-responsive miRNAs in foxtail millet: genome-wide identification, characterization and expression profiling.

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Yadav, Amita; Khan, Yusuf; Prasad, Manoj

2016-03-01

A set of novel and known dehydration-responsive miRNAs have been identified in foxtail millet. These findings provide new insights into understanding the functional role of miRNAs and their respective targets in regulating plant response to dehydration stress. MicroRNAs perform significant regulatory roles in growth, development and stress response of plants. Though the miRNA-mediated gene regulatory networks under dehydration stress remain largely unexplored in plant including foxtail millet (Setaria italica), which is a natural abiotic stress tolerant crop. To find out the dehydration-responsive miRNAs at the global level, four small RNA libraries were constructed from control and dehydration stress treated seedlings of two foxtail millet cultivars showing contrasting tolerance behavior towards dehydration stress. Using Illumina sequencing technology, 55 known and 136 novel miRNAs were identified, representing 22 and 48 miRNA families, respectively. Eighteen known and 33 novel miRNAs were differentially expressed during dehydration stress. After the stress treatment, 32 dehydration-responsive miRNAs were up-regulated in tolerant cultivar and 22 miRNAs were down-regulated in sensitive cultivar, suggesting that miRNA-mediated molecular regulation might play important roles in providing contrasting characteristics to these cultivars. Predicted targets of identified miRNAs were found to encode various transcription factors and functional enzymes, indicating their involvement in broad spectrum regulatory functions and biological processes. Further, differential expression patterns of seven known miRNAs were validated by northern blot and expression of ten novel dehydration-responsive miRNAs were confirmed by SL-qRT PCR. Differential expression behavior of five miRNA-target genes was verified under dehydration stress treatment and two of them also validated by RLM RACE. Overall, the present study highlights the importance of dehydration stress-associated post

Thermal dehydration kinetics of phosphogypsum

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López, F. A.

2015-09-01

Full Text Available Phsophogypsum is a by-product from the processing phosphate rock. Before the use of it in cement industry such as setting regulator is necessary a study of dehydration reaction of phosphogypsum to avoid the false setting during the milling. The aim is to study the thermal behavior of two different phosphogypsum sources (Spain and Tunisia under non-isothermal conditions in argon atmosphere by using Thermo-Gravimetriy, Differential Thermal Analysis (TG-DTA and Differential Scanning Calorimetry (DSC. DSC experiments were carried out at temperatures ranging from ambient to 350 °C at different heating rates. The temperatures of conversion from gypsum to hemihydrate and anhydrite states and heat of dehydration were determined. Various methods were used to analyze the DSC data for reaction kinetics determination. The activation energy and frequency factor were calculated for dehydration of phosphogypsum. Activation energy values of the main dehydration reaction of phosphogypsum were calculated to be approximately 61–118 kJ/mol.El fosfoyeso es un subproducto procedente del procesado de la roca fosfato. Una de las posibles vías de reutilización y revalorización es su uso como regulador del fraguado en la industria cementera. Debido a los posibles problemas de falso fraguado asociado a los procesos de deshidratación que tienen lugar durante la molienda del cemento, esta investigación estudió el comportamiento térmico, bajo condiciones no-isotérmicas en atmósfera de argón, de dos fosfoyesos, mediante TG-DTA y DSC. Los ensayos de DSC se realizaron hasta los 350 °C a diferentes velocidades de calentamiento. La temperatura de conversión del yeso a las formas de hemihidrato y anhidrita y el calor de hidratación fueron determinados. Las cinéticas de reacción fueron obtenidas analizando los datos de DSC mediante varios métodos. Se calculó la energía de activación y el factor de frecuencia para las reacciones de deshidratación del

Simple synthesis of P(Cbz-alt-TBT) and PCDTBT by combining direct arylation with suzuki polycondensation of heteroaryl chlorides.

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Lombeck, Florian; Matsidik, Rukiya; Komber, Hartmut; Sommer, Michael

2015-01-01

Direct arylation (DA) of 2-chlorothiophene and 2-chloro-3-hexylthiophene with 4,7-dibromo-2,1,3-benzothiadiazole is used to synthesize 4,7-bis(5-chloro-2-thienyl)-2,1,3-benzothiadiazole (TBTCl2) and 4,7-bis(5-chloro-4-hexyl-2-thienyl)-2,1,3-benzothiadiazole (DH-TBTCl2) in one step. Suitable conditions of the Suzuki polycondensations (SPC) of TBTCl2 and DH-TBTCl2 with the carbazole comonomer CbzPBE2 are established, furnishing PCDTBT and P(Cbz-alt-TBT) with high molecular weight and yield. Compared with control samples made from the corresponding dibromides, high-temperature NMR and UV-vis spectroscopy indicate similar properties for PCDTBT but an increased content of Cbz-Cbz homocouplings for P(Cbz-alt-TBT). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Value of point-of-care ketones in assessing dehydration and acidosis in children with gastroenteritis.

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Levy, Jason A; Waltzman, Mark; Monuteaux, Michael C; Bachur, Richard G

2013-11-01

Children with gastroenteritis often develop dehydration with metabolic acidosis. Serum ketones are frequently elevated in this population. The goal was to determine the relationship between initial serum ketone concentration and both the degree of dehydration and the magnitude of acidosis. This was a secondary analysis of a prospective trial of crystalloid administration for rapid rehydration. Children 6 months to 6 years of age with gastroenteritis and dehydration were enrolled. A point-of-care serum ketone (beta-hydroxybutyrate) concentration was obtained at the time of study enrollment. The relationship between initial serum ketone concentration and a prospectively assigned and previously validated clinical dehydration score, and serum bicarbonate concentration, was analyzed. A total of 188 patients were enrolled. The median serum ketone concentration was elevated at 3.1 mmol/L (interquartile range [IQR] = 1.2 to 4.6 mmol/L), and the median dehydration score was consistent with moderate dehydration. A significant positive relationship was found between serum ketone concentration and the clinical dehydration score (Spearman's rho = 0.22, p = 0.003). Patients with moderate dehydration had a higher median serum ketone concentration than those with mild dehydration (3.6 mmol/L vs. 1.4 mmol/L, p = 0.007). Additionally, the serum ketone concentration was inversely correlated with serum bicarbonate concentration (ρ = -0.26, p Children with gastroenteritis and dehydration have elevated serum ketone concentrations that correlate with both degree of dehydration and magnitude of metabolic acidosis. Point-of-care serum ketone measurement may be a useful tool to inform management decisions at the point of triage or in the initial evaluation of children with gastroenteritis and dehydration. © 2013 by the Society for Academic Emergency Medicine.

External validation of the clinical dehydration scale for children with acute gastroenteritis.

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Bailey, Benoit; Gravel, Jocelyn; Goldman, Ran D; Friedman, Jeremy N; Parkin, Patricia C

2010-06-01

The objective was to validate the clinical dehydration scale (CDS) for children with gastroenteritis in a different pediatric emergency department (ED) from where it was initially derived and validated. A prospective cohort study was performed in a tertiary care pediatric ED over a 1-year period. A sample of triage nurses were trained in applying the CDS. The CDS consists of four clinical characteristics (general appearance, eyes, mucous membranes, and tears), each of which are scored 0, 1, or 2 for a total score of 0 to 8, with 0 representing no dehydration; 1 to 4, some dehydration; and 5 to 8, moderate/severe dehydration. Children 1 month to 5 years of age with vomiting and/or diarrhea who had the CDS documented at triage and a final diagnosis of gastroenteritis, gastritis, or enteritis were enrolled. Exclusion criteria included a chronic disease, treatment with intravenous (IV) rehydration within the previous 24 hours, visit to the ED for the same illness in the 7 days prior to arrival, and diarrhea of more than 10 days' duration. The primary outcome was the length of stay (LOS) in the ED from the time of seeing a physician to discharge, analyzed with a Kruskal-Wallis test. From April 2008 to March 2009, 150 patients with a mean (+/-SD) age of 22 (+/-14) months (range = 4 months to 4 years) were enrolled. Fifty-six patients had no dehydration, 74 had some dehydration, and 20 had moderate/severe dehydration. The median LOS in the ED after being seen by a physician was significantly longer as children appeared more dehydrated according to the CDS: 54 minutes (interquartile range [IQR] = 26-175 minutes), 128 minutes (IQR = 25-334 minutes), and 425 minutes (IQR = 218-673 minutes) for the no, some, and moderate/severe dehydration groups, respectively (p children with gastroenteritis in a different pediatric center than the original one where it was developed. It is a good predictor of LOS in the ED after being seen by a physician. (c) 2010 by the Society for

The Usefulness of Clinical and Laboratory Parameters for Predicting Severity of Dehydration in Children with Acute Gastroenteritis

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Hoxha, Teuta Faik; Azemi, Mehmedali; Avdiu, Muharrem; Ismaili-jaha, Vlora; Grajqevci, Violeta; Petrela, Ela

2014-01-01

ABSTRACT Background: An accurate assessment of the degree of dehydration in infants and children is important for proper decision-making and treatment. This emphasizes the need for laboratory tests to improve the accuracy of clinical assessment of dehydration. The aim of this study was to assess the relationship between clinical and laboratory parameters in the assessment of dehydration. Methods: We evaluated prospectively 200 children aged 1 month to 5 years who presented with diarrhea, vomiting or both. Dehydration assessment was done following a known clinical scheme. Results: We enrolled in the study 200 children (57.5% were male). The mean age was 15.62±9.03 months, with more than half those studied being under 24 months old. Overall, 46.5% (93) had mild dehydration, 34% (68) had moderate dehydration, 5.5% (11) had severe dehydration whereas, 14% (28) had no dehydration. Patients historical clinical variables in all dehydration groups did not differ significantly regarding age, sex, fever, frequency of vomiting, duration of diarrhea and vomiting, while there was a trend toward severe dehydration in children with more frequent diarrhea (p=0.004). Serum urea and creatinine cannot discriminate between mild and moderate dehydration but they showed a good specificity for severe dehydration of 99% and 100% respectively. Serum bicarbonates and base excess decreased significantly with a degree of dehydration and can discriminate between all dehydration groups (P<0.001). Conclusion: Blood gases were useful to diagnose the degree of dehydration status among children presenting with acute gastroenteritis. Serum urea and creatinine were the most specific tests for severe dehydration diagnosis. Historical clinical patterns apart from frequency of diarrhea did not correlate with dehydration status. Further studies are needed to validate our results. PMID:25568559

Fresh or dehydrated spineless cactus in diets for lambs

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Solano Felipe Just de Andrade

2016-05-01

Full Text Available The objective was to evaluate the effect of partial or total replacement of Tifton 85 hay with fresh or dehydrated spineless cactus on performance and body weight components of sheep. Thirty hair lambs, with 19 kg ± 0.35 kg initial weight, were randomly divided into five treatments, namely: Tifton 85 Hay (HA; Tifton 85 Hay + fresh spineless cactus (HAFC; Tifton 85 Hay + dehydrated spineless cactus (HADC; fresh spineless cactus (FC; dehydrated spineless cactus (DC. In addition to the spineless cactus and hay, the complete mixture contained soybean meal, mineral salt and limestone in all treatments. Animals were confined for 75 days and then slaughtered. The weight of body components was recorded. Dry matter intake, total digestible nutrients intake and voluntary water intake were higher (p 0.05 by treatments. The cold carcass weight, rib eye area, weight and yield of the skin, liver, kidney and large intestine were higher (p < 0.05 for the DC and HADC treatments. Partial or total replacement of Tifton 85 hay with fresh or dehydrated spineless cactus, in complete diets for sheep, increases the weight of the cold carcass and non-carcass components.

A fatal case of hypernatraemic dehydration in a neonate.

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Staub, Eveline; Wilkins, Barry

2012-09-01

Problems with lactation can result in hypernatraemic dehydration in the neonate, with potentially severe adverse consequences. This is illustrated in this fatal case of a 10 day old neonate who presented with excessive hypernatraemic dehydration due to insufficient breast milk intake, resulting in cerebral sinus vein thrombosis with cerebral haemorrhage and infarction. Differential diagnosis included excessive sodium intake (through inappropriately mixed formula or house remedies or through hyperaldosteronism) and high water deficit (renal or gastrointestinal losses, nephrogenic or central diabetes insipidus), all of which were ruled out by specific investigations or history. No evidence was found for inborn error of metabolism. The dehydration in this baby, however, was accentuated by trans-epidermal water loss due to an ichthyosiform skin condition. This first ever reported Australian fatality from neonatal hypernatraemic dehydration supports the concern of health care professionals over rising incidences of this entity in exclusively breastfed infants, and should encourage endorsement of improved monitoring of weight loss in newborns and breastfeeding support for their mothers. © 2012 The Authors. Journal of Paediatrics and Child Health © 2012 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Chemical clearing and dehydration of GFP expressing mouse brains.

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Becker, Klaus; Jährling, Nina; Saghafi, Saiedeh; Weiler, Reto; Dodt, Hans-Ulrich

2012-01-01

Generally, chemical tissue clearing is performed by a solution consisting of two parts benzyl benzoate and one part benzyl alcohol. However, prolonged exposure to this mixture markedly reduces the fluorescence of GFP expressing specimens, so that one has to compromise between clearing quality and fluorescence preservation. This can be a severe drawback when working with specimens exhibiting low GFP expression rates. Thus, we screened for a substitute and found that dibenzyl ether (phenylmethoxymethylbenzene, CAS 103-50-4) can be applied as a more GFP-friendly clearing medium. Clearing with dibenzyl ether provides improved tissue transparency and strikingly improved fluorescence intensity in GFP expressing mouse brains and other samples as mouse spinal cords, or embryos. Chemical clearing, staining, and embedding of biological samples mostly requires careful foregoing tissue dehydration. The commonly applied tissue dehydration medium is ethanol, which also can markedly impair GFP fluorescence. Screening for a substitute also for ethanol we found that tetrahydrofuran (CAS 109-99-9) is a more GFP-friendly dehydration medium than ethanol, providing better tissue transparency obtained by successive clearing. Combined, tetrahydrofuran and dibenzyl ether allow dehydration and chemical clearing of even delicate samples for UM, confocal microscopy, and other microscopy techniques.

Dehydration and hydration behavior of metal-salt-modified materials for chemical heat pumps

International Nuclear Information System (INIS)

Ishitobi, Hirokazu; Uruma, Keirei; Takeuchi, Masato; Ryu, Junichi; Kato, Yukitaka

2013-01-01

Lithium chloride (LiCl) modified magnesium hydroxide (Mg(OH) 2 ) is a potential new material for chemical heat pumps. However, there is insufficient information concerning its dehydration and hydration behavior. In this study, the dehydration and hydration reactions, corresponding to the heat storage and the heat output operations, respectively, of authentic Mg(OH) 2 and LiCl-modified Mg(OH) 2 were investigated by thermogravimetric methods and near infrared spectroscopy. The dehydration of authentic Mg(OH) 2 proceeded as a one-step reaction. In contrast, the dehydration of LiCl-modified Mg(OH) 2 occurred in two steps. The dehydration reaction rates were increased by LiCl modification of the Mg(OH) 2 surface, while the activation energy for the first-order dehydration reaction was lowered. The mechanism for the hydration reaction of magnesium oxide (MgO) was different to that for the hydration of LiCl-modified MgO. This difference was explained by the effect of the LiCl on the MgO particle surface. - Highlights: ► LiCl-modified Mg(OH) 2 is a candidate material for chemical heat pumps. ► The dehydration reaction of LiCl-modified Mg(OH) 2 is a two-step reaction. ► The dehydration reaction of Mg(OH) 2 was enhanced by LiCl modification. ► The hydration mechanisms of authentic MgO and LiCl-modified MgO were different.

Relationship of Renal Function Tests and Electrolyte Levels with Severity of Dehydration in Acute Diarrhea.

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Gauchan, E; Malla, K K

2015-01-01

Acute diarrheal illness constitutes a major cause of morbidity and mortality in children in developing countries. Most of the complications of diarrhea occur due to excessive fluid and electrolyte loss; adverse complications are seen more with increasing severity of dehydration. This study was conducted to identify the relation of renal function and electrolyte abnormalities in children with varying severity of dehydration. This study was carried out in Manipal Teaching Hospital, Pokhara, Nepal over duration of one year. The aims were to find out the association of renal function and electrolyte disturbances with type of diarrhea, severity of dehydration and their relation to outcome. All children more than one month and less than 15 years with acute diarrhea were included in the study. Data were entered and analyzed by SPSS version 19. Statistical analysis applied was Chi-square test. A p-value of Dehydration was associated more with Acute Watery Diarrhea than with Invasive Diarrhea. Renal function and electrolyte abnormalities were seen more in Acute Watery Diarrhea with increasing levels of blood urea, serum creatinine and abnormal levels of serum sodium seen with increased severity of dehydration. Abnormalities in renal function and electrolytes correlated significantly with severity of dehydration. The outcome of patients correlated with severity of dehydration with mortality occurring in 18.1% of patients with Severe dehydration, 0.8% of Some dehydration with no mortality in the No dehydration group.

Apple's dehydration by the irradiation pretreatment

International Nuclear Information System (INIS)

Fu Junjie; Chao Yan; Shen Weiqiao; Wang Jun

2001-01-01

"6"0 Co γ-ray irradiation was used as a pre-treatment method to dry the apple. The aim of this study was to discover the effect factor concerning the change of the apple cell structure which would affect the speed of drhydration and the relation between the speed of hot air dehydration and the irradiation dose. The results demonstrated that with the increasing of irradiation dose. The damage of apple's vacuole membrane increased. The positive correlation was shown in slice thickness and dehydration rate, the relation of the irradiation dose and the temperature of hot air was negatively correlated. The optimum of pre-treatment was gained for slice thickness, the irradiation dose and dry temperature of hot air. (authors)

The usefulness of clinical and laboratory parameters for predicting severity of dehydration in children with acute gastroenteritis.

Science.gov (United States)

Hoxha, Teuta Faik; Azemi, Mehmedali; Avdiu, Muharrem; Ismaili-Jaha, Vlora; Grajqevci, Violeta; Petrela, Ela

2014-10-01

An accurate assessment of the degree of dehydration in infants and children is important for proper decision-making and treatment. This emphasizes the need for laboratory tests to improve the accuracy of clinical assessment of dehydration. The aim of this study was to assess the relationship between clinical and laboratory parameters in the assessment of dehydration. We evaluated prospectively 200 children aged 1 month to 5 years who presented with diarrhea, vomiting or both. Dehydration assessment was done following a known clinical scheme. We enrolled in the study 200 children (57.5% were male). The mean age was 15.62±9.03 months, with more than half those studied being under 24 months old. Overall, 46.5% (93) had mild dehydration, 34% (68) had moderate dehydration, 5.5% (11) had severe dehydration whereas, 14% (28) had no dehydration. Patients historical clinical variables in all dehydration groups did not differ significantly regarding age, sex, fever, frequency of vomiting, duration of diarrhea and vomiting, while there was a trend toward severe dehydration in children with more frequent diarrhea (p=0.004). Serum urea and creatinine cannot discriminate between mild and moderate dehydration but they showed a good specificity for severe dehydration of 99% and 100% respectively. Serum bicarbonates and base excess decreased significantly with a degree of dehydration and can discriminate between all dehydration groups (Pdehydration status among children presenting with acute gastroenteritis. Serum urea and creatinine were the most specific tests for severe dehydration diagnosis. Historical clinical patterns apart from frequency of diarrhea did not correlate with dehydration status. Further studies are needed to validate our results.

The independent influences of heat strain and dehydration upon cognition.

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van den Heuvel, Anne M J; Haberley, Benjamin J; Hoyle, David J R; Taylor, Nigel A S; Croft, Rodney J

2017-05-01

Many researchers have addressed the potential effects of hyperthermia and dehydration on cognition, often revealing contradictory outcomes. A possible reason for this inconsistency is that experiments may have been inadequately designed for such effects. In this study, the impact of hyperthermia, dehydration and their combination on cognition were evaluated in eight young males, after accounting for a range of experimental limitations. Passive heating and thermal clamping at two mean body temperatures (36.5, 38.5 °C) were performed under three hydration states (euhydrated, 3 and 5% dehydrated) to assess their effects on difficulty-matched working memory and visual perception tasks, and on a difficulty manipulated perceptual task. Data were analysed according to signal detection theory to isolate changes in response sensitivity, bias and speed. Neither moderate hyperthermia (P = 0.141) nor dehydration (P > 0.604) modified response sensitivity, nor did they significantly interact (P > 0.698). Therefore, the ability to distinguish correct from incorrect responses was unaffected. Nevertheless, hyperthermia, but not dehydration (P = 0.301), reduced the response bias (-0.08 versus 2.2 [normothermia]; P = 0.010) and reaction time (mean reduction 49 ms; P < 0.001), eliciting more liberal and faster responses (P = 0.010). Response bias was reduced for the memory relative to the perceptual task (P = 0.037), and this effect was enhanced during hyperthermia (P = 0.031). These observations imply that, once potentially confounding influences were controlled, moderate hyperthermia, significant dehydration and their combined effects had insufficient impact to impair cognition within the memory and perceptual domains tested. Nonetheless, moderate hyperthermia elicited more liberal and rapid responses.

Effects of irradiation on decontamination and nutrients of dehydrated longan

International Nuclear Information System (INIS)

Zhu Jiating; Feng Min; Tang Yuxin; Lin Jiabin; Yang Ping; Wang Dening

2011-01-01

The dehydrated longan were irradiated at the doses of 2, 4, 6, 8 and 10 kGy and the effects of irradiation on nutrients contents and decontamination were studied. Results showed that dehydrated longan were irradiated at 6 kGy, the number of total bacterial count, mold and coliform bacteria accorded with national standards. There were no significant influence on contents of crude fat, ash, Fe, P, Na and V B2 , but the contents of protein, crude fiber, carbohydrate, moisture, Ca, K and V C of irradiated deghdrated longan were significantly different with control. 6-10 kGy irradiation could meet the commercial demands of dehydrated longan decontamination. (authors)

Recent Advances on Bioethanol Dehydration using Zeolite Membrane

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Makertihartha, I. G. B. N.; Dharmawijaya, P. T.; Wenten, I. G.

2017-07-01

Renewable energy has gained increasing attention throughout the world. Bioethanol has the potential to replace existing fossil fuel usage without much modification in existing facilities. Bioethanol which generally produced from fermentation route produces low ethanol concentration. However, fuel grade ethanol requires low water content to avoid engine stall. Dehydration process has been increasingly important in fuel grade ethanol production. Among all dehydration processes, pervaporation is considered as the most promising technology. Zeolite possesses high potential in pervaporation of bioethanol into fuel grade ethanol. Zeolite membrane can either remove organic (ethanol) from aqueous mixture or water from the mixture, depending on the framework used. Hydrophilic zeolite membrane, e.g. LTA, can easily remove water from the mixture leaving high ethanol concentration. On the other hand, hydrophobic zeolite membrane, e.g. silicate-1, can remove ethanol from aqueous solution. This review presents the concept of bioethanol dehydration using zeolite membrane. Special attention is given to the performance of selected pathway related to framework selection.

Methods to increase the rate of mass transfer during osmotic dehydration of foods.

Science.gov (United States)

Chwastek, Anna

2014-01-01

Traditional methods of food preservation such as freezing, freeze drying (lyophilization), vacuum drying, convection drying are often supplemented by new technologies that enable obtaining of high quality products. Osmotic dehydration is more and more often used during processing of fruits and vegetables. This method allows maintaining good organoleptic and functional properties in the finished product. Obtaining the desired degree of dehydration or saturation of the material with an osmoactive substance often requires  elongation of time or use of high temperatures. In recent years much attention was devoted to techniques aimed at increasing the mass transfer between the dehydrated material and the hypertonic solution. The work reviews the literature focused on methods of streamlining the process of osmotic dehydration which include the use of: ultrasound, high hydrostatic pressure, vacuum osmotic dehydration and pulsed electric field.

Dehydration-induced modulation of κ-opioid inhibition of vasopressin neurone activity

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Scott, Victoria; Bishop, Valerie R; Leng, Gareth; Brown, Colin H

2009-01-01

Dehydration increases vasopressin (antidiuretic hormone) secretion from the posterior pituitary gland to reduce water loss in the urine. Vasopressin secretion is determined by action potential firing in vasopressin neurones, which can exhibit continuous, phasic (alternating periods of activity and silence), or irregular activity. Autocrine κ-opioid inhibition contributes to the generation of activity patterning of vasopressin neurones under basal conditions and so we used in vivo extracellular single unit recording to test the hypothesis that changes in autocrine κ-opioid inhibition drive changes in activity patterning of vasopressin neurones during dehydration. Dehydration increased the firing rate of rat vasopressin neurones displaying continuous activity (from 7.1 ± 0.5 to 9.0 ± 0.6 spikes s−1) and phasic activity (from 4.2 ± 0.7 to 7.8 ± 0.9 spikes s−1), but not those displaying irregular activity. The dehydration-induced increase in phasic activity was via an increase in intraburst firing rate. The selective κ-opioid receptor antagonist nor-binaltorphimine increased the firing rate of phasic neurones in non-dehydrated rats (from 3.4 ± 0.8 to 5.3 ± 0.6 spikes s−1) and dehydrated rats (from 6.4 ± 0.5 to 9.1 ± 1.2 spikes s−1), indicating that κ-opioid feedback inhibition of phasic bursts is maintained during dehydration. In a separate series of experiments, prodynorphin mRNA expression was increased in vasopressin neurones of hyperosmotic rats, compared to hypo-osmotic rats. Hence, it appears that dynorphin expression in vasopressin neurones undergoes dynamic changes in proportion to the required secretion of vasopressin so that, even under stimulated conditions, autocrine feedback inhibition of vasopressin neurones prevents over-excitation. PMID:19822541

Validation of the clinical dehydration scale for children with acute gastroenteritis.

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Goldman, Ran D; Friedman, Jeremy N; Parkin, Patricia C

2008-09-01

We previously created a clinical dehydration scale. Our objective was to validate the clinical dehydration scale with a new cohort of patients with acute gastroenteritis who were assessed in a tertiary emergency department in a developed country. A prospective observational study was performed in an emergency department at a large pediatric tertiary center in Canada. Children 1 month to 5 years of age with symptoms of acute gastroenteritis who were assessed in the emergency department were enrolled consecutively during a 4-month period. The main outcome measures were length of stay, proportion of children receiving intravenous fluid rehydration, and proportions of children with abnormal serum pH values or bicarbonate levels. A total of 205 children were enrolled, with a mean age of 22.4 +/- 14.9 months; 103 (50%) were male. The distribution of severity categories was as follows: no dehydration (score of 0), n = 117 (57%); some dehydration (score of 1-4), n = 83 (41%); moderate/severe dehydration (score of 5-8), n = 5 (2%). The 3 dehydration categories were significantly different with respect to the validation hypotheses (length of stay, mean +/- SD: none, 245 +/- 181 minutes; some, 397 +/- 302 minutes; moderate/severe, 501 +/- 389 minutes; treatment with intravenous fluids: none, n =17, 15%; some, n = 41, 49%; moderate/severe, n = 4, 80%; number of vomiting episodes in the 7 days before the emergency department visit: none, 8.4 +/- 7.7 episodes; some, 13 +/- 10.7 episodes; moderate/severe, 30.2 +/- 14.8 episodes). The clinical dehydration scale and the 3 severity categories were valid for a prospectively enrolled cohort of patients who were assessed in our tertiary emergency department. The scoring system was valuable in predicting a longer length of stay and the need for intravenous fluid rehydration for children with symptoms of acute gastroenteritis.

Dehydration of Glucose to 5-Hydroxymethylfurfural Using Nb-doped Tungstite

KAUST Repository

Yue, Chaochao

2016-08-05

Dehydration of glucose to 5-hydroxymethylfurfural (HMF) remains a significant problem in the context of the valorization of lignocellulosic biomass. Hydrolysis of WCl6 and NbCl5 leads to precipitation of Nb-containing tungstite (WO3H2O) at low Nb content and mixtures of tungstite and niobic acid at higher Nb content. Tungstite is a promising catalyst for the dehydration of glucose to HMF. Compared with Nb2O5, fewer by-products are formed because of the low BrOnsted acidity of the (mixed) oxides. In water, an optimum yield of HMF was obtained for Nb-W oxides with low Nb content owing to balanced Lewis and BrOnsted acidity. In THF/water, the strong Lewis acidity and weak BrOnsted acidity caused the reaction to proceed through isomerization to fructose and dehydration of fructose to a partially dehydrated intermediate, which was identified by LC-ESI-MS. The addition of HCl to the reaction mixture resulted in rapid dehydration of this intermediate to HMF. The HMF yield obtained in this way was approximately 56% for all tungstite catalysts. Density functional theory calculations show that the Lewis acid centers on the tungstite surface can isomerize glucose into fructose. Substitution of W by Nb lowers the overall activation barrier for glucose isomerization by stabilizing the deprotonated glucose adsorbate.

Synthesis of Carbocyclic Hydantocidins via Regioselective and Diastereoselective Phosphine-Catalyzed [3 + 2]-Cycloadditions to 5-Methylenehydantoins

Energy Technology Data Exchange (ETDEWEB)

Pham, Tien Q.; Pyne, Stephen G.; Skelton, Brian W.; White, Allan H. (UWA); (Wollongong)

2010-07-20

The phosphine-catalyzed [3 + 2]-cycloaddition of 5-methylenehydantoins 4 with the ylides 5, derived from addition of tributylphosphine to the 2-butynoic acid derivatives, 6a-d, gives spiro-heterocyclic products. The camphor sultam derivative 6b gives optically active products. Noteable was that the ylides derived from ethyl 2-butynoate and the 3-(2-butynoyl)-1,3-oxazolidin-2-one derivatives 6c and 6d gave spiro-heterocyclic products with reverse regioselectivities. The N,N-dibenzylprotected cycloadduct has been converted to carbocyclic hydantocidin and 6,7-diepi-carbocyclic hydantocidin.

Regioselective Acetylation of C21 Hydroxysteroids by the Bacterial Chloramphenicol Acetyltransferase I.

Science.gov (United States)

Mosa, Azzam; Hutter, Michael C; Zapp, Josef; Bernhardt, Rita; Hannemann, Frank

2015-07-27

Chloramphenicol acetyltransferase I (CATI) detoxifies the antibiotic chloramphenicol and confers a corresponding resistance to bacteria. In this study we identified this enzyme as a steroid acetyltransferase and designed a new and efficient Escherichia-coli-based biocatalyst for the regioselective acetylation of C21 hydroxy groups in steroids of pharmaceutical interest. The cells carried a recombinant catI gene controlled by a constitutive promoter. The capacity of the whole-cell system to modify different hydroxysteroids was investigated, and NMR spectroscopy revealed that all substrates were selectively transformed into the corresponding 21-acetoxy derivatives. The biotransformation was optimized, and the reaction mechanism is discussed on the basis of a computationally modeled substrate docking into the crystal structure of CATI. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effective hepatitis A virus inactivation during low-heat dehydration of contaminated green onions.

Science.gov (United States)

Laird, David T; Sun, Yan; Reineke, Karl F; Shieh, Y Carol

2011-08-01

Preserving fruits and vegetables by dehydration is common; however, information is limited concerning viral survival on the produce during the process. This work demonstrated the effects of low heat dehydration on inactivating hepatitis A virus (HAV) on contaminated green onions. Inoculated and uninoculated onion samples were dehydrated at target temperatures of 45-65 °C for 20 h. HAV from artificially contaminated onions (fresh or dehydrated) was eluted by shaking at 145 rpm at 20 °C for 20 min with 3% beef extract, pH 8, and followed by 0.2 μM-membrane filtration before plaque assay and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis. Dilutions of the filtrates were made for obtaining countable plaques on FRhK-4 cell monolayers in 6-well plates, and also for eliminating inhibitors in qRT-PCR. Average water activity of the onions after 20 h-dehydration was 0.227, regardless of temperature used (47.9 °C or 65.1 °C). Eight dehydration trials resulted in a linear relationship between HAV inactivation and dehydration temperature, with HAV log reduction = 0.1372x(°C) - 5.5572, r(2) = 0.88. Therefore, the 20 h-heating at 47.8, 55.1, and 62.4 °C reduced infectious HAV in onions by 1, 2, and 3 logs respectively, the Z value being 7.3 °C. It was concluded that low heat dehydration using 62.5 °C or above could effectively inactivate HAV on contaminated onions by >3 logs. Published by Elsevier Ltd.

An organ-specific role for ethylene in rose petal expansion during dehydration and rehydration

Science.gov (United States)

Liu, Daofeng; Liu, Xiaojing; Meng, Yonglu; Sun, Cuihui; Tang, Hongshu; Jiang, Yudong; Khan, Muhammad Ali; Xue, Jingqi; Ma, Nan; Gao, Junping

2013-01-01

Dehydration is a major factor resulting in huge loss from cut flowers during transportation. In the present study, dehydration inhibited petal cell expansion and resulted in irregular flowers in cut roses, mimicking ethylene-treated flowers. Among the five floral organs, dehydration substantially elevated ethylene production in the sepals, whilst rehydration caused rapid and elevated ethylene levels in the gynoecia and sepals. Among the five ethylene biosynthetic enzyme genes (RhACS1–5), expression of RhACS1 and RhACS2 was induced by dehydration and rehydration in the two floral organs. Silencing both RhACS1 and RhACS2 significantly suppressed dehydration- and rehydration-induced ethylene in the sepals and gynoecia. This weakened the inhibitory effect of dehydration on petal cell expansion. β-glucuronidase activity driven by both the RhACS1 and RhACS2 promoters was dramatically induced in the sepals, pistil, and stamens, but not in the petals of transgenic Arabidopsis. This further supports the organ-specific induction of these two genes. Among the five rose ethylene receptor genes (RhETR1–5), expression of RhETR3 was predominantly induced by dehydration and rehydration in the petals. RhETR3 silencing clearly aggravated the inhibitory effect of dehydration on petal cell expansion. However, no significant difference in the effect between RhETR3-silenced flowers and RhETR-genes-silenced flowers was observed. Furthermore, RhETR-genes silencing extensively altered the expression of 21 cell expansion-related downstream genes in response to ethylene. These results suggest that induction of ethylene biosynthesis by dehydration proceeds in an organ-specific manner, indicating that ethylene can function as a mediator in dehydration-caused inhibition of cell expansion in rose petals. PMID:23599274

Transcriptional and physiological data reveal the dehydration memory behavior in switchgrass (Panicum virgatum L.).

Science.gov (United States)

Zhang, Chao; Peng, Xi; Guo, Xiaofeng; Tang, Gaijuan; Sun, Fengli; Liu, Shudong; Xi, Yajun

2018-01-01

Switchgrass ( Panicum virgatum L.) is a model biofuel plant because of its high biomass, cellulose-richness, easy degradation to ethanol, and the availability of extensive genomic information. However, a little is currently known about the molecular responses of switchgrass plants to dehydration stress, especially multiple dehydration stresses. Studies on the transcriptional profiles of 35-day-old tissue culture plants revealed 741 dehydration memory genes. Gene Ontology and pathway analysis showed that these genes were enriched in phenylpropanoid biosynthesis, starch and sucrose metabolism, and plant hormone signal transduction. Further analysis of specific pathways combined with physiological data suggested that switchgrass improved its dehydration resistance by changing various aspects of its responses to secondary dehydration stress (D2), including the regulation of abscisic acid (ABA) and jasmonic acid (JA) biosynthesis and signal transduction, the biosynthesis of osmolytes (l-proline, stachyose and trehalose), energy metabolism (i.e., metabolic process relating to photosynthetic systems, glycolysis, and the TCA cycle), and lignin biosynthesis. The transcriptional data and chemical substance assays showed that ABA was significantly accumulated during both primary (D1) and secondary (D2) dehydration stresses, whereas JA accumulated during D1 but became significantly less abundant during D2. This suggests the existence of a complicated signaling network of plant hormones in response to repeated dehydration stresses. A homology analysis focusing on switchgrass, maize, and Arabidopsis revealed the conservation and species-specific distribution of dehydration memory genes. The molecular responses of switchgrass plants to successive dehydration stresses have been systematically characterized, revealing a previously unknown transcriptional memory behavior. These results provide new insights into the mechanisms of dehydration stress responses in plants. The genes and

Mechanisms by Which Dehydration May Lead to Chronic Kidney Disease.

Science.gov (United States)

Roncal-Jimenez, C; Lanaspa, M A; Jensen, T; Sanchez-Lozada, L G; Johnson, R J

2015-01-01

Dehydration, a condition that characterizes excessive loss of body water, is well known to be associated with acute renal dysfunction; however, it has largely been considered reversible and to be associated with no long-term effects on the kidney. Recently, an epidemic of chronic kidney disease has emerged in Central America in which the major risk factor seems to be recurrent heat-associated dehydration. This has led to studies investigating whether recurrent dehydration may lead to permanent kidney damage. Three major potential mechanisms have been identified, including the effects of vasopressin on the kidney, the activation of the aldose reductase-fructokinase pathway, and the effects of chronic hyperuricemia. The discovery of these pathways has also led to the recognition that mild dehydration may be a risk factor in progression of all types of chronic kidney diseases. Furthermore, there is some evidence that increasing hydration, particularly with water, may actually prevent CKD. Thus, a whole new area of investigation is developing that focuses on the role of water and osmolarity and their influence on kidney function and health. © 2015 S. Karger AG, Basel.

Carotid Flow Time Test Performance for the Detection of Dehydration in Children With Diarrhea.

Science.gov (United States)

Mackenzie, David C; Nasrin, Sabiha; Atika, Bita; Modi, Payal; Alam, Nur H; Levine, Adam C

2017-11-09

Unstructured clinical assessments of dehydration in children are inaccurate. Point-of-care ultrasound is a noninvasive diagnostic tool that can help evaluate the volume status; the corrected carotid artery flow time has been shown to predict volume depletion in adults. We sought to determine the ability of the corrected carotid artery flow time to identify dehydration in a population of children presenting with acute diarrhea in Dhaka, Bangladesh. Children presenting with acute diarrhea were recruited and rehydrated according to hospital protocols. The corrected carotid artery flow time was measured at the time of presentation. The percentage of weight change with rehydration was used to categorize each child's dehydration as severe (>9%), some (3%-9%), or none (dehydration. Linear regression was used to model the relationship between the corrected carotid artery flow time and percentage of dehydration. A total of 350 children (0-60 months) were enrolled. The mean corrected carotid artery flow time was 326 milliseconds (interquartile range, 295-351 milliseconds). The area under the receiver operating characteristic curve for the detection of severe dehydration was 0.51 (95% confidence interval, 0.42, 0.61). Linear regression modeling showed a weak association between the flow time and dehydration. The corrected carotid artery flow time was a poor predictor of severe dehydration in this population of children with diarrhea. © 2017 by the American Institute of Ultrasound in Medicine.

Improvements in the order, isotropy and electron density of glypican-1 crystals by controlled dehydration

Energy Technology Data Exchange (ETDEWEB)

Awad, Wael [Lund University, Box 124, 221 00 Lund (Sweden); Cairo University, Cairo (Egypt); Svensson Birkedal, Gabriel [Lund University, Biomedical Center A13, 221 84 Lund (Sweden); Thunnissen, Marjolein M. G. M. [Lund University, Box 124, 221 00 Lund (Sweden); Lund University, Box 188, 221 00 Lund (Sweden); Mani, Katrin [Lund University, Biomedical Center A13, 221 84 Lund (Sweden); Logan, Derek T., E-mail: derek.logan@biochemistry.lu.se [Lund University, Box 124, 221 00 Lund (Sweden)

2013-12-01

The anisotropy of crystals of glypican-1 was significantly reduced by controlled dehydration using the HC1 device, allowing the building of previously disordered parts of the structure. The use of controlled dehydration for improvement of protein crystal diffraction quality is increasing in popularity, although there are still relatively few documented examples of success. A study has been carried out to establish whether controlled dehydration could be used to improve the anisotropy of crystals of the core protein of the human proteoglycan glypican-1. Crystals were subjected to controlled dehydration using the HC1 device. The optimal protocol for dehydration was developed by careful investigation of the following parameters: dehydration rate, final relative humidity and total incubation time T{sub inc}. Of these, the most important was shown to be T{sub inc}. After dehydration using the optimal protocol the crystals showed significantly reduced anisotropy and improved electron density, allowing the building of previously disordered parts of the structure.

Approximate Mathematical Modeling of Osmotic Dehydration of Cone-Shaped Fruits and Vegetables in Hypertonic Solutions

Directory of Open Access Journals (Sweden)

Mohammad Sirousazar

2017-07-01

Full Text Available Water loss kinetics in osmotic dehydration of cone-shaped fruits and vegetables was modeled on the basis of diffusion mechanism, using the Fick’s second law. The model was developed by taking into account the influences of the fruit geometrical characteristics, initial water content of fruit, water diffusion coefficient in fruit, and the water concentration in hypertonic solution. Based on the obtained model, it was shown that the water diffusion coefficient and the initial water concentration of fruit have direct effects on the dehydration rate and also inverse influence on the dehydration duration. The geometrical parameters of fruit and water concentration in hypertonic solution showed direct effect on the dehydration duration as well as inverse effect on the dehydration rate. The presented model seems to be useful tool to predict the dehydration kinetics of cone-shaped fruit during osmotic dehydration process and to optimize the process prior to perform the experiments.

Methods for assessing the effects of dehydration on cognitive function.

Science.gov (United States)

Lieberman, Harris R

2012-11-01

Studying the effects of dehydration on cognitive function presents a variety of unique and difficult challenges to investigators. These challenges, which are addressed in this article, can be divided into three general categories: 1) choosing an appropriate method of generating a consistent level of dehydration; 2) determining and effectively employing appropriate and sensitive measures of cognitive state; and 3) adequately controlling the many confounding factors that interfere with assessment of cognitive function. The design and conduct of studies on the effects of dehydration on cognitive function should carefully consider various methodological issues, and investigators should carefully weigh the benefits and disadvantages of particular methods and procedures. © 2012 International Life Sciences Institute.

mPGES-1-derived PGE2 mediates dehydration natriuresis

Science.gov (United States)

Jia, Zhanjun; Liu, Gang; Sun, Ying; Kakizoe, Yutaka; Guan, Guangju; Zhang, Aihua; Zhou, Shu-Feng

2013-01-01

PGE2 is a natriuretic factor whose production is elevated after water deprivation (WD) but its role in dehydration natriuresis is not well-defined. The goal of the present study was to investigate the role of microsomal prostaglandin E synthase-1 (mPGES-1) in dehydration natriuresis. After 24-h WD, wild-type (WT) mice exhibited a significant increase in 24-h urinary Na+ excretion accompanied with normal plasma Na+ concentration and osmolality. In contrast, WD-induced elevation of urinary Na+ excretion was completely abolished in mPGES-1 knockout (KO) mice in parallel with increased plasma Na+ concentration and a trend increase in plasma osmolality. WD induced a 1.8-fold increase in urinary PGE2 output and a 1.6-fold increase in PGE2 content in the renal medulla of WT mice, both of which were completely abolished by mPGES-1 deletion. Similar patterns of changes were observed for urinary nitrate/nitrite and cGMP. The natriuresis in dehydrated WT mice was associated with a significant downregulation of renal medullary epithelial Na channel-α mRNA and protein, contrasting to unaltered expressions in dehydrated KO mice. By quantitative RT-PCR, WD increased the endothelial nitric oxide synthase (eNOS), inducible NOS, and neuronal NOS expressions in the renal medulla of WT mice by 3.9-, 1.48-, and 2.6-fold, respectively, all of which were significantly blocked in mPGES-1 KO mice. The regulation of eNOS expression was further confirmed by immunoblotting. Taken together, our results suggest that mPGES-1-derived PGE2 contributes to dehydration natriuresis likely via NO/cGMP. PMID:23171554

Thermodynamic characteristics of dehydration of hexahydrates of erbium, thulium and lutetium chlorides

International Nuclear Information System (INIS)

Ukraintseva, Eh.A.; Sokolova, N.P.; Logvinenko, V.A.

1991-01-01

Temperature dependence of water vapour equilibrium pressure over the compounds of ErCl 3 ·6H-2O, TmCl 3 ·6H 2 O and LuCl 3 ·6H 2 O is studied by membrane method within the temperature range of 309-403 K. Dehydration process stoichiometry is determined thermogravimetrically under quasi-equilibrium conditions. All three compounds split off three molecules at the first stage of dehydration. ErCl 3 ·6H 2 O and TmCl 2 ·6H 2 O are very similar to terbium and disprosium chloride hexahydrates by vapour pressure value and dehydration enthalpy; enthalpy of the first dehydration stage is of the same character as those of nedymium, gadolinium and holmium chloride haxahydrates

Chemical clearing and dehydration of GFP expressing mouse brains.

Directory of Open Access Journals (Sweden)

Klaus Becker

Full Text Available Generally, chemical tissue clearing is performed by a solution consisting of two parts benzyl benzoate and one part benzyl alcohol. However, prolonged exposure to this mixture markedly reduces the fluorescence of GFP expressing specimens, so that one has to compromise between clearing quality and fluorescence preservation. This can be a severe drawback when working with specimens exhibiting low GFP expression rates. Thus, we screened for a substitute and found that dibenzyl ether (phenylmethoxymethylbenzene, CAS 103-50-4 can be applied as a more GFP-friendly clearing medium. Clearing with dibenzyl ether provides improved tissue transparency and strikingly improved fluorescence intensity in GFP expressing mouse brains and other samples as mouse spinal cords, or embryos. Chemical clearing, staining, and embedding of biological samples mostly requires careful foregoing tissue dehydration. The commonly applied tissue dehydration medium is ethanol, which also can markedly impair GFP fluorescence. Screening for a substitute also for ethanol we found that tetrahydrofuran (CAS 109-99-9 is a more GFP-friendly dehydration medium than ethanol, providing better tissue transparency obtained by successive clearing. Combined, tetrahydrofuran and dibenzyl ether allow dehydration and chemical clearing of even delicate samples for UM, confocal microscopy, and other microscopy techniques.

Gene expression changes governing extreme dehydration tolerance in an Antarctic insect

Science.gov (United States)

Teets, Nicholas M.; Peyton, Justin T.; Colinet, Herve; Renault, David; Kelley, Joanna L.; Kawarasaki, Yuta; Lee, Richard E.; Denlinger, David L.

2012-01-01

Among terrestrial organisms, arthropods are especially susceptible to dehydration, given their small body size and high surface area to volume ratio. This challenge is particularly acute for polar arthropods that face near-constant desiccating conditions, as water is frozen and thus unavailable for much of the year. The molecular mechanisms that govern extreme dehydration tolerance in insects remain largely undefined. In this study, we used RNA sequencing to quantify transcriptional mechanisms of extreme dehydration tolerance in the Antarctic midge, Belgica antarctica, the world’s southernmost insect and only insect endemic to Antarctica. Larvae of B. antarctica are remarkably tolerant of dehydration, surviving losses up to 70% of their body water. Gene expression changes in response to dehydration indicated up-regulation of cellular recycling pathways including the ubiquitin-mediated proteasome and autophagy, with concurrent down-regulation of genes involved in general metabolism and ATP production. Metabolomics results revealed shifts in metabolite pools that correlated closely with changes in gene expression, indicating that coordinated changes in gene expression and metabolism are a critical component of the dehydration response. Finally, using comparative genomics, we compared our gene expression results with a transcriptomic dataset for the Arctic collembolan, Megaphorura arctica. Although B. antarctica and M. arctica are adapted to similar environments, our analysis indicated very little overlap in expression profiles between these two arthropods. Whereas several orthologous genes showed similar expression patterns, transcriptional changes were largely species specific, indicating these polar arthropods have developed distinct transcriptional mechanisms to cope with similar desiccating conditions. PMID:23197828

Dehydration Kinetics of Chlorite at High Temperatures and Geophysical Implications

Science.gov (United States)

Shen, K.; Wang, D.; Liu, T.

2017-12-01

A significant amount of water is released from hydrous phases in subduction zones and the brought into the earth's interior. The resulting flux may trigger earthquakes and arc magmatism. Chlorite is one of the most important hydrous minerals with a high water content of 13.0 wt.% in the deep subduction zones, and the dehydration of chlorites are thought to be associated with many anomalies geophysical observations. To understand the nature of the geology and geophysical phenomenon, further research on the dehydration of chlorite should be carried out. Here we report the new results on dehydration kinetics of chlorite at high temperatures. We investigated the dehydration kinetics of chlorite using thermogravimetric analyses (TGA) and X-ray diffraction. The dehydration experiments were conducted with heating rates of 15, 20, 25 K/min up to 1466K. The fitted TGA data results indicate that the probable dehydroxylation mechanism of chlorite is a three-dimensional diffusion reaction with the Fick's second law. The results reveal that the dehydroxylation reaction can be divided into two stages corresponding to the hydroxyls in the two different layers: the first stage between 853 K and 973 K is related to the dehydroxylation of the interlayer hydroxide with the activation energy (Ea) of 159 kJ/ mol and pre-exponential factor (D0) value of 1.53x10-5 m2/s; the second stage between 973 K and 1093 K with an Ea value of 189 kJ/mol and D0 of 2.1x10-5 m2/s is due to the dehydroxylation of the `talc' layer. The mineral reactions and products were observed by high-temperature X-ray diffraction. There are metastable phases during reactions and product phases exhibited a topotactic relationship. The dehydroxylation reaction of chlorite is controlled by an inhomogeneous mechanism. We determine that the fluid production rates of chlorite are 2.7x10-4s-1, 4.5x10-4s-1, 7.3x10-4s-1, 1.2x10-3s-1, 1.7x10-4s-1, at 863 K, 883 K, 903 K, 923 K, 943 K for isothermal dehydration reaction. Our

Dehydration and acute weight gain in mixed martial arts fighters before competition.

Science.gov (United States)

Jetton, Adam M; Lawrence, Marcus M; Meucci, Marco; Haines, Tracie L; Collier, Scott R; Morris, David M; Utter, Alan C

2013-05-01

The purpose of this study was to characterize the magnitude of acute weight gain (AWG) and dehydration in mixed martial arts (MMA) fighters before competition. Urinary measures of hydration status and body mass were determined approximately 24 hours before and then again approximately 2 hours before competition in 40 MMA fighters (mean ± SE, age: 25.2 ± 0.65 years, height: 1.77 ± 0.01 m, body mass: 75.8 ± 1.5 kg). The AWG was defined as the amount of body weight the fighters gained in the approximately 22-hour period between the official weigh-in and the actual competition. On average, the MMA fighters gained 3.40 ± 2.2 kg or 4.4% of their body weight in the approximately 22-hour period before competition. Urine specific gravity significantly decreased (p 1.021 immediately before competition indicating significant or serious dehydration. The MMA fighters undergo significant dehydration and fluctuations in body mass (4.4% avg.) in the 24-hour period before competition. Urinary measures of hydration status indicate that a significant proportion of MMA fighters are not successfully rehydrating before competition and subsequently are competing in a dehydrated state. Weight management guidelines to prevent acute dehydration in MMA fighters are warranted to prevent unnecessary adverse health events secondary to dehydration.

Osmotic dehydration of Braeburn variety apples in the production of sustainable food products

Science.gov (United States)

Ciurzyńska, Agnieszka; Cichowska, Joanna; Kowalska, Hanna; Czajkowska, Kinga; Lenart, Andrzej

2018-01-01

The aim of this work was to investigate the effects of osmotic dehydration conditions on the properties of osmotically pre-treated dried apples. The scope of research included analysing the most important mass exchange coefficients, i.e. water loss, solid gain, reduced water content and water activity, as well as colour changes of the obtained dried product. In the study, apples were osmotically dehydrated in one of two 60% solutions: sucrose or sucrose with an addition of chokeberry juice concentrate, for 30 and 120 min, in temperatures of 40 and 60°C. Ultrasound was also used during the first 30 min of the dehydration process. After osmotic pre-treatment, apples were subjected to innovative convective drying with the puffing effect, and to freeze-drying. Temperature and dehydration time increased the effectiveness of mass exchange during osmotic dehydration. The addition of chokeberry juice concentrate to standard sucrose solution and the use of ultrasound did not change the value of solid gain and reduced water content. Water activity of the dried apple tissue was not significantly changed after osmotic dehydration, while changes in colour were significant.

A New Freezing Method Using Pre-Dehydration by Microwave-Vacuum Drying

Science.gov (United States)

Tsuruta, Takaharu; Hamidi, Nurkholis

Partial dehydration by microwave-vacuum drying has been applied to tuna and strawberry in order to reduce cell-damages caused by the formation of large ice-crystals during freezing. The samples were subjected to microwave vacuum drying at pressure of 5 kPa and temperature less than 27°C to remove small amount of water prior to freezing. The tuna were cooled by using the freezing chamber at temperature -50°C or -150°C, while the strawberries were frozen at temperature -30°C or -80°C, respectively. The temperature transients in tuna showed that removing some water before freezing made the freezing time shorter. The observations of ice crystal clearly indicated that rapid cooling and pre-dehydration prior to freezing were effective in minimizing the size of ice crystal. It is also understood that the formation of large ice crystals has a close relation to the cell damages. After thawing, the observation of microstructure was done on the tuna and strawberry halves. The pre-dehydrated samples showed a better structure than the un-dehydrated one. It is concluded that the pre-dehydration by microwave-vacuum drying is one promising method for the cryo-preservation of foods.

Transcriptome sequencing and whole genome expression profiling of chrysanthemum under dehydration stress

Science.gov (United States)

2013-01-01

Background Chrysanthemum is one of the most important ornamental crops in the world and drought stress seriously limits its production and distribution. In order to generate a functional genomics resource and obtain a deeper understanding of the molecular mechanisms regarding chrysanthemum responses to dehydration stress, we performed large-scale transcriptome sequencing of chrysanthemum plants under dehydration stress using the Illumina sequencing technology. Results Two cDNA libraries constructed from mRNAs of control and dehydration-treated seedlings were sequenced by Illumina technology. A total of more than 100 million reads were generated and de novo assembled into 98,180 unique transcripts which were further extensively annotated by comparing their sequencing to different protein databases. Biochemical pathways were predicted from these transcript sequences. Furthermore, we performed gene expression profiling analysis upon dehydration treatment in chrysanthemum and identified 8,558 dehydration-responsive unique transcripts, including 307 transcription factors and 229 protein kinases and many well-known stress responsive genes. Gene ontology (GO) term enrichment and biochemical pathway analyses showed that dehydration stress caused changes in hormone response, secondary and amino acid metabolism, and light and photoperiod response. These findings suggest that drought tolerance of chrysanthemum plants may be related to the regulation of hormone biosynthesis and signaling, reduction of oxidative damage, stabilization of cell proteins and structures, and maintenance of energy and carbon supply. Conclusions Our transcriptome sequences can provide a valuable resource for chrysanthemum breeding and research and novel insights into chrysanthemum responses to dehydration stress and offer candidate genes or markers that can be used to guide future studies attempting to breed drought tolerant chrysanthemum cultivars. PMID:24074255

Recent development in osmotic dehydration of fruit and vegetables: a review.

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Chandra, Suresh; Kumari, Durvesh

2015-01-01

Osmotic dehydration of fruits and vegetables is achieved by placing the solid/semi solid, whole or in pieces, in a hypertonic solution (sugar and/or salt) with a simultaneous counter diffusion of solutes from the osmotic solution into the tissues. Osmotic dehydration is recommended as a processing method to obtain better quality of food products. Partial dehydration allows structural, nutritional, sensory, and other functional properties of the raw material to be modified. However, the food industry uptake of osmotic dehydration of foods has not been extensive as expected due to the poor understanding of the counter current flow phenomena associated with it. However, these flows are in a dynamic equilibrium with each other and significantly influence the final product in terms of preservation, nutrition, and organoleptic properties. The demand of healthy, natural, nutritious, and tasty processed food products continuously increases, not only for finished products, but also for ingredient to be included in complex foods such as ice cream, cereals, dairy, confectionaries, and bakery products.

DEHYDRATION OF LOW WATER CONTENT ETHANOL

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Pervaporation has emerged as an economically viable alternative technology for the dehydration of organic solvents, removal of organic compounds from water and organic/organic separations. Development of a membrane system with suitable flux and selectivity characteristics plays a...

Mild dehydration modifies the cerebrovascular response to the cold pressor test.

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Perry, Blake G; Bear, Tracey L K; Lucas, Samuel J E; Mündel, Toby

2016-01-01

The cold pressor test (CPT) is widely used in clinical practice and physiological research. It is characterized by a robust autonomic response, with associated increases in heart rate (HR), mean arterial pressure (MAP) and mean middle cerebral artery blood flow velocity (MCAv(mean)). Hydration status is not commonly reported when conducting this test, yet blood viscosity alone can modulate MCAv(mean), potentially modifying the MCAv(mean) response to the CPT. We investigated the effect of mild dehydration on the physiological response to the CPT in 10 healthy men (mean ± SD: age 28 ± 5 years; body mass 83 ± 5 kg). All participants completed two CPTs, cold water (0°C) immersion of both feet for 90 s, with the order of the euhydration and dehydration trials counterbalanced. Beat-to-beat MCAv, MAP, HR and breath-by-breath partial pressure of end-tidal CO2 (P(ET,CO2)) were measured continuously. Participants' pain perception was measured 1 min into the CPT using a visual analog scale (no pain = 0; maximal pain = 10). Dehydration significantly elevated plasma osmolality and urine specific gravity and reduced body mass (all P 0.05). After 90 s of immersion, the change in MCAv(mean) from baseline was less in the dehydration compared with the euhydration trial (change 0 ± 5 versus 7 ± 7 cm s(-1), P = 0.01), as was P(ET,CO2) (change -3 ± 2 versus 0 ± 3 mmHg, P = 0.02). Dehydration was associated with greater relative pain sensation during the CPT (7.0 ± 1.3 vs 5.8 ± 1.8, P = 0.02). Our results demonstrate that mild dehydration can modify the cerebrovascular response to the CPT, with dehydration increasing perceived pain, lowering P ET ,CO2 and, ultimately, blunting the MCAv(mean) response. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

Dehydration kinetics of a natural montmorillonite

International Nuclear Information System (INIS)

Andreotti, G.; Loria, A.; Mazzega, E.; Valeri, S.

1978-01-01

The dehydration mass loss of samples of montmorillonite (a layered hydrated silicate) was measured in an environment at constant temperature and at constant undersatured water vapour content. The hydration curves were analyzed by assuming the model of thermally activated, monoenergetic and first-order process compatible with the experimental results. Two dehydration kinetics with activation energies (0.21+-0.02) eV and (0.34+-0.02) eV were found that can be related to the existence of two kinds of water (structured and nonstructured) in the hydrated silicate interlayers. The possibility of an icelike structure of a fraction of the adsorbed molecules is briefly discussed. The experimental results show, furthermore, that in the investigated hydration range (up to about 10% in mass) the fraction of structured water has a maximum when the hydration is about 6%. (author)

Dehydration is an independent predictor of discharge outcome and admission cost in acute ischaemic stroke.

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Liu, C-H; Lin, S-C; Lin, J-R; Yang, J-T; Chang, Y-J; Chang, C-H; Chang, T-Y; Huang, K-L; Ryu, S-J; Lee, T-H

2014-09-01

Our aim was to investigate the influence of admission dehydration on the discharge outcome in acute ischaemic and hemorrhagic stroke. Between January 2009 and December 2011, 4311 ischaemic and 1371 hemorrhagic stroke patients from the stroke registry of Chang Gung healthcare system were analyzed. The eligible patients were identified according to inclusion/exclusion criteria. In total, 2570 acute ischaemic and 573 acute hemorrhagic stroke patients were finally recruited. According to the blood urea nitrogen (BUN) to creatinine (Cr) ratio (BUN/Cr), these patients were divided into dehydrated (BUN/Cr ≥ 15) and non-dehydrated (BUN/Cr dehydration had higher infection rates (P = 0.006), worse discharge BI (62.8 ± 37.4 vs. 73.4 ± 32.4, P dehydration. However, acute hemorrhagic stroke with or without admission dehydration showd no difference in admission costs (P = 0.618) and discharge outcomes (BI, P = 0.058; mRS, P = 0.058). Admission dehydration is associated with worse discharge outcomes and higher admission costs in acute ischaemic stroke but not in hemorrhagic stroke. © 2014 The Author(s) European Journal of Neurology © 2014 EAN.

Copper Nitrate Mediated Regioselective [2+2+1] Cyclization of Alkynes with Alkenes: A Cascade Approach to Δ(2)-Isoxazolines.

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Gao, Mingchun; Li, Yingying; Gan, Yuansheng; Xu, Bin

2015-07-20

An efficient method for the regioselective synthesis of pharmacologically relevant polysubstituted Δ(2)-isoxazolines is based on the copper-mediated direct transformation of simple terminal alkynes and alkenes. The overall process involves the formation of four chemical bonds with inexpensive and readily available copper nitrate trihydrate as a novel precursor of nitrile oxides. The reaction can be easily handled and proceeds under mild conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Regioselective hydroxylation of isoflavones by Streptomyces avermitilis MA-4680.

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Roh, Changhyun; Seo, Su-Hyun; Choi, Kwon-Young; Cha, Minho; Pandey, Bishnu Prasad; Kim, June-Hyung; Park, Jun-Seong; Kim, Duck Hee; Chang, Ih Seop; Kim, Byung-Gee

2009-07-01

Screening of bacterial whole cells was performed for regioselective hydroxylation of daidzein and genistein. Among the strains examined, Streptomyces avermitilis MA-4680 showed high ortho-dihydroxylation activity to produce 3',4',7-trihydroxyisoflavone and 3',4',5,7-tetrahydroxyisoflavone from daidzein (4',7-dihydroxyisoflavone) and genistein (4',5,7-trihydroxyisoflavone), respectively. Using 100 mg cells (wet wt.) and 1% (v/v) Triton X100 in 1 ml of total reaction volume, where 100 microl of the substrate solution (0.5 mM in 10% (v/v) mixed solvent of DMSO:MeOH = 3:7) was added to 900 microl of potassium phosphate buffer (100 mM, pH 7.2), a 16% molar conversion yield of 3',4',7-trihydroxyisoflavone was obtained from 0.5 mM daidzein after 24 h of reaction time at 28 degrees C and 200 rpm. Ketoconazole significantly (ca. 90%) inhibited the ortho-hydroxylation activity of daidzein, suggesting that cytochrome P450 enzymes putatively play roles in regiospecific daidzein hydroxylation. The analysis of the reaction products was determined by gas chromatography/mass spectrometry (GC/MS) and (1)H NMR.

Use of bedside ultrasound to assess degree of dehydration in children with gastroenteritis.

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Chen, Lei; Hsiao, Allen; Langhan, Melissa; Riera, Antonio; Santucci, Karen A

2010-10-01

Prospectively identifying children with significant dehydration from gastroenteritis is difficult in acute care settings. Previous work by our group has shown that bedside ultrasound (US) measurement of the inferior vena cava (IVC) and the aorta (Ao) diameter ratio is correlated with intravascular volume. This study was designed to validate the use of this method in the prospective identification of children with dehydration by investigating whether the IVC/Ao ratio correlated with dehydration in children with acute gastroenteritis. Another objective was to investigate the interrater reliability of the IVC/Ao measurements. A prospective observational study was carried out in a pediatric emergency department (PED) between November 2007 and June 2009. Children with acute gastroenteritis were enrolled as subjects. A pair of investigators obtained transverse images of the IVC and Ao using bedside US. The ratio of IVC and Ao diameters (IVC/Ao) was calculated. Subjects were asked to return after resolution of symptoms. The difference between the convalescent weight and ill weight was used to calculate the degree of dehydration. Greater than or equal to 5% difference was judged to be significant. Linear regression was performed with dehydration as the dependent variable and the IVC/Ao as the independent variable. Pearson's correlation coefficient was calculated to assess the degree of agreement between observers. A total of 112 subjects were enrolled. Seventy-one subjects (63%) completed follow-up. Twenty-eight subjects (39%) had significant dehydration. The linear regression model resulted in an R² value of 0.21 (p dehydration. Forty-eight paired measurements of IVC/Ao ratios were made. The Pearson correlation coefficient was 0.76.   In this pilot study the ratio of IVC to Ao diameters, as measured by bedside US, was a marginally accurate measurement of acute weight loss in children with dehydration from gastroenteritis. The technique demonstrated good interrater

Cross-conjugated Trienamine Catalysis with α'-Alkylidene 2-Cyclohexenones: Application in β,γ-Regioselective Aza-Diels-Alder Reaction.

Science.gov (United States)

Zhou, Zhi; Wang, Zhou-Xiang; Ouyang, Qin; Xiao, Wei; Du, Wei; Chen, Ying-Chun

2017-02-24

Endo-type cross-conjugated trienamines between highly congested α'-alkylidene 2-cyclohexenones and a chiral primary amine catalyst serve as HOMO-raised dienophiles in inverse-electron-demand aza-Diels-Alder cycloadditions with a number of 1-azadiene substrates. The reactions exhibit exclusive β,γ-regioselectivity, and multifunctional products with high molecular complexity are efficiently constructed in excellent diastereo- and enantioselectivity (>19:1 d.r., up to 99 % ee). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrophobic Hyflon® AD/PVDF membranes for butanol dehydration via pervaporation

KAUST Repository

Jalal, Taghreed; Bettahalli Narasimha, Murthy Srivatsa; Le, Ngoc Lieu; Nunes, Suzana Pereira

2015-01-01

Novel hydrophobic Hyflon® AD /PVDF membranes were developed and investigated for n-butanol dehydration via pervaporation. The coating protocols for thin defect-free Hyflon® AD selective layer on the PVDF support was optimized. Water and n-butanol transport was measured, analyzing the effect of operating conditions. The water flux through the newly developed membranes was higher than 150 g/m2.h with selectivity for water higher than 99 wt %. The focus was on the use of Hyflon® AD as the selective layer for n-butanol dehydration. The membrane application can be extended to other solvents, supporting an effective and simple method for dehydration with hydrophobic membranes.

Hydrophobic Hyflon® AD/PVDF membranes for butanol dehydration via pervaporation

KAUST Repository

Jalal, Taghreed

2015-10-21

Novel hydrophobic Hyflon® AD /PVDF membranes were developed and investigated for n-butanol dehydration via pervaporation. The coating protocols for thin defect-free Hyflon® AD selective layer on the PVDF support was optimized. Water and n-butanol transport was measured, analyzing the effect of operating conditions. The water flux through the newly developed membranes was higher than 150 g/m2.h with selectivity for water higher than 99 wt %. The focus was on the use of Hyflon® AD as the selective layer for n-butanol dehydration. The membrane application can be extended to other solvents, supporting an effective and simple method for dehydration with hydrophobic membranes.

Dehydration enhances pain-evoked activation in the human brain compared with rehydration.

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Ogino, Yuichi; Kakeda, Takahiro; Nakamura, Koji; Saito, Shigeru

2014-06-01

Negative effects of dehydration on the human brain and cognitive function have been reported. In this study, we examined the effects of dehydration on pain thresholds and cortical activations in response to pain, compared with rehydration with an oral rehydration solution (ORS) by functional magnetic resonance imaging. Five healthy adult men were subjected to dehydration and rehydration on 2 different days. The condition on the first day was randomly assigned to each subject. They completed a 40-minute exercise protocol using a walking machine after 12 hours of fasting under both conditions. For rehydration, the subjects consumed up to 3000 mL ORS starting from the night before the test day. After exercise, a painful stimulus (cold pressor test) was applied to the subjects' medial forearm in a magnetic resonance imaging scanning gantry, and pain-evoked brain activation was analyzed. On the rehydration day, each of the subjects consumed an average of 2040 mL (range; 1800-2500 mL) ORS. Physiological data revealed that subjects when dehydrated lost more weight from exercise than subjects when rehydrated had a larger heart rate increase, a higher tympanic temperature, and a higher urine osmolality. Subjective data revealed that the subjects reported significantly stronger thirst while dehydrated than while rehydrated with ORS, although the levels of hunger and anxiety and mood did not significantly differ between conditions. The cold pressor test robustly activated the pain-related neural network, notably the anterior cingulate cortex, insula, and thalamus. Such activations in the dehydrated subjects were greater than those in the rehydrated subjects in terms of peak and cluster, accompanied by a decrease in pain threshold (P = 0.001). Our findings suggest that dehydration brings about increased brain activity related to painful stimuli together with enhanced thirst, whereas rehydration with ORS alleviates thirst and decreases brain activity related to painful stimuli.

The management of children with gastroenteritis and dehydration in the emergency department.

Science.gov (United States)

Colletti, James E; Brown, Kathleen M; Sharieff, Ghazala Q; Barata, Isabel A; Ishimine, Paul

2010-06-01

Acute gastroenteritis is characterized by diarrhea, which may be accompanied by nausea, vomiting, fever, and abdominal pain. To review the evidence on the assessment of dehydration, methods of rehydration, and the utility of antiemetics in the child presenting with acute gastroenteritis. The evidence suggests that the three most useful predictors of 5% or more dehydration are abnormal capillary refill, abnormal skin turgor, and abnormal respiratory pattern. Studies are conflicting on whether blood urea nitrogen (BUN) or BUN/creatinine ratio correlates with dehydration, but several studies found that low serum bicarbonate combined with certain clinical parameters predicts dehydration. In most studies, oral or nasogastric rehydration with an oral rehydration solution was equally efficacious as intravenous (i.v.) rehydration. Many experts discourage the routine use of antiemetics in young children. However, children receiving ondensetron are less likely to vomit, have greater oral intake, and are less likely to be treated by intravenous rehydration. Mean length of Emergency Department (ED) stay is also less, and very few serious side effects have been reported. In the ED, dehydration is evaluated by synthesizing the historical and physical examination, and obtaining laboratory data points in select patients. No single laboratory value has been found to be accurate in predicting the degree of dehydration and this is not routinely recommended. The evidence suggests that the majority of children with mild to moderate dehydration can be treated successfully with oral rehydration therapy. Ondansetron (orally or intravenously) may be effective in decreasing the rate of vomiting, improving the success rate of oral hydration, preventing the need for i.v. hydration, and preventing the need for hospital admission in those receiving i.v. hydration. Copyright 2010. Published by Elsevier Inc.

Egg clutch dehydration induces early hatching in red-eyed treefrogs, Agalychnis callidryas

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María José Salica

2017-07-01

Full Text Available Terrestrial eggs have evolved repeatedly in tropical anurans exposing embryos to the new threat of dehydration. Red-eyed treefrogs, Agalychnis callidryas, lay eggs on plants over water. Maternally provided water allows shaded eggs in humid sites to develop to hatching without rainfall, but unshaded eggs and those in less humid sites can die from dehydration. Hatching responses of amphibian eggs to dry conditions are known from two lineages with independent origins of terrestrial eggs. Here, we experimentally tested for dehydration-induced early hatching in another lineage (Agalychnis callidryas, Phyllomedusidae, representing a third independent origin of terrestrial eggs. We also investigated how dehydration affected egg and clutch structure, and egg mortality. We collected clutches from a pond in Gamboa, Panama, and randomly allocated them to wet or dry treatments at age 1 day. Embryos hatched earlier from dry clutches than from wet clutches, accelerating hatching by ∼11%. Clutch thickness and egg diameter were affected by dehydration, diverging between treatments over time. Meanwhile, mortality in dry clutches was six-fold higher than in control clutches. With this study, early hatching responses to escape mortality from egg dehydration are now known from three anuran lineages with independent origins of terrestrial eggs, suggesting they may be widespread. Further studies are needed to understand how terrestrial amphibian eggs can respond to, or will be affected by, rapid changes in climate over the next decades.

Treatment of mild to moderate dehydration in children with oral rehydration therapy.

Science.gov (United States)

Diggins, Kristene C

2008-08-01

To review current literature on the effectiveness of oral rehydration therapy (ORT) in the treatment of mild to moderate dehydration in children. Recommendations from American Academy of Pediatrics (AAP), World Health Organization (WHO), selected research articles (2000-2006), and Internet sources. Dehydration is a common diagnosis in pediatric primary care. The literature indicates that dehydration is more often treated with intravenous (IV) therapy when ORT would be equally effective. ORT is an effective treatment for children with mild to moderate dehydration. ORT could be used more frequently rather than IV rehydration therapy. The use of ORT versus traditional methods of IV hydration matches the nursing philosophy of holistic care by enhancing client comfort and autonomy. Current practice in the treatment of mild to moderate dehydration in children does not match both AAP and WHO guidelines, which are based on evidence supporting ORT effectiveness. Treatment with ORT allows children more flexibility to be treated at home and thus decreases hospital stay. Evidence shows that the time required to initiate ORT is actually quicker than IV therapy and allows for a less stressful therapy that can be performed in the home.

Dehydration at admission increased the need for dialysis in hemolytic uremic syndrome children.

Science.gov (United States)

Balestracci, Alejandro; Martin, Sandra Mariel; Toledo, Ismael; Alvarado, Caupolican; Wainsztein, Raquel Eva

2012-08-01

Oligoanuric forms of postdiarrheal hemolytic uremic syndrome (D+ HUS) usually have more severe acute stage and higher risk of chronic sequelae than nonoligoanuric forms. During the diarrheal phase, gastrointestinal losses could lead to dehydration with pre-renal injury enhancing the risk of oligoanuric D+ HUS. Furthermore, it had been shown that intravenous volume expansion during the prodromal phase could decrease the frequency of oligoanuric renal failure. Thus, we performed this retrospective study to determine whether dehydration on admission is associated with increased need for dialysis in D+ HUS patients. Data from 137 children was reviewed, which were divided into two groups according to their hydration status at admission: normohydrated (n = 86) and dehydrated (n = 51). Laboratory parameters of the dehydrated patients reflected expected deteriorations (higher urea, higher hematocrit and lower sodium, bicarbonate, and pH) than normohydrated ones. Likewise, the dehydrated group had a higher rate of vomiting and need for dialysis (70.6 versus 40.7 %, p = 0.0007). Our data suggests that dehydration at hospital admission might represent a concomitant factor aggravating the intrinsic renal disease in D+ HUS patients increasing the need for dialysis. Therefore, the early recognition of patients at risk of D+ HUS is encouraged to guarantee a well-hydrated status.

Synthesis of 6-[18F] and 4-[18F]fluoro-L-m-tyrosines via regioselective radiofluorodestannylation

International Nuclear Information System (INIS)

Namavari, Mohammad; Satyamurthy, N.; Phelps, M.E.; Barrio, J.R.; California Univ., Los Angeles, CA

1993-01-01

The regioselective radiofluorodestannylation of 6-trimethylstannyl-L-m-tyrosine derivative with [ 18 F]F 2 and [ 18 F]acetyl hypofluorite afforded, after acid hydrolysis, 6-[ 18 F]fluoro-L-m-tyrosine in radiochemical yields of 23 and 17%, respectively. Similarly, 4-[ 18 F]fluoro-L-m-tyrosine was synthesized in 11% radiochemical yield from the corresponding 4-trimethylstannyl-L-m-tyrosine derivative using [ 18 F]F 2 . The structural analyses of precursors, intermediates, and the final products (after 18 F decay), were carried out by 1 H, 13 C, 19 F, 119 Sn-NMR and high resolution mass spectroscopy. (author)

Gastric emptying of liquids in rats dehydrated by water deprivation

Directory of Open Access Journals (Sweden)

Baracat E.C.E.

1997-01-01

Full Text Available The gastric emptying of liquids was investigated in male Wistar rats (8 to 10 weeks old, 210-300 g dehydrated by water deprivation. In this model of dehydration, weight loss, hematocrit and plasma density were significantly higher in the dehydrated animals than in the control groups after 48 and 72 h of water deprivation (P<0.05. Three test meals (saline (N = 10, water (N = 10 and a WHO rehydrating solution containing in one liter 90 mEq sodium, 20 mEq potassium, 80 mEq chloride and 30 mEq citrate (N = 10 were used to study gastric emptying following water deprivation for 24, 48 and 72 h. After 72 h, gastric emptying of the water (39.4% retention and rehydrating solution (49.2% retention test meals was significantly retarded compared to the corresponding control groups (P<0.05, Mann-Whitney test. The 72-h period of deprivation was used to study the recovery from dehydration, and water was supplied for 60 or 120 min after 67 h of deprivation. Body weight loss, hematocrit and plasma density tended to return to normal when water was offered for 120 min. In the animals supplied with water for 60 min, there was a recovery in the gastric emptying of water while the gastric emptying of the rehydrating solution was still retarded (53.1% retention; P<0.02, Kruskal-Wallis test. In the group supplied with water for 120 min, the gastric emptying of the rehydrating (51.7% retention and gluco-saline (46.0% retention solutions tended to be retarded (P = 0.04, Kruskal-Wallis test. In this model of dehydration caused by water deprivation, with little alteration in the body electrolyte content, gastric emptying of the rehydrating solution was retarded after rehydration with water. We conclude that the mechanisms whereby receptors in the duodenal mucosa can modify gastric motility are altered during dehydration caused by water deprivation

Modern approaches to the treatment of dehydration in children and adults

Directory of Open Access Journals (Sweden)

S.O. Kramariov

2017-10-01

Full Text Available Dehydration is the cause of many lethal outcomes, primarily due to diarrhea. The significant achievement that made it possible to save millions of human lives was the creation of oral rehydration salt (ORS. ORS for the treatment of dehydration in infectious diarrhea was created at the International Centre for Diarrhoeal Diseases Research, Bangladesh in the late 60s of the XX century for the treatment of cholera. Subsequently, for the treatment of non-cholera diarrhea, an improved ORS formula was developed. According to the World Health Organization, as compared with a standard ORS solution, a solution that has reduced osmolarity can decrease the need for intravenous infusion by 33 %. In addition, this solution also reduces the incidence of vomiting by 30 % and stool frequency by 20 %. 68.5 % of children with respiratory diseases, who were admitted to an infectious hospital, had signs of dehydration. In common with diarrhea, dehydration in respiratory diseases is one of the indicators of severity of the patient’s condition. Oral rehydration is currently used in different countries of the world in 99 % of children suffering from diarrhea. Timely and adequate rehydration therapy is a primary and most important part in the treatment of dehydration in both children and adults. Early use of adequate rehydration therapy is a prerequisite for the rapid and successful treatment of the disease.

Sugar beet molasses: Properties and applications in osmotic dehydration of fruits and vegetables

Directory of Open Access Journals (Sweden)

Šarić Ljubiša Ć.

2016-01-01

Full Text Available Molasses is an important by-product of sugar beet or sugar cane refining industry and it was one of the first sweeteners used in human nutrition. Sugar cane molasses has unique characteristics that can make it suitable for application in food industry, especially in confectionery and bakery products. On the other hand, sugar beet molasses has not had greater application in the human diet, primarily because of its strong smell and taste of the beet, which makes it unattractive for consumption. Since recent investigations showed that sugar beet molasses can be used as a hypertonic solution in osmotic dehydration of different materials of plant and animal origin, the objective of this work was to review recently studied sugar beet molasses in terms of its applications in osmotic dehydrations of fruits and vegetables. Previous studies showed that sugar beet molasses is an excellent medium for osmotic dehydration of fruits and vegetables (apple, carrot, plum, etc. primarily due to a high content of dry matter (80%, w/w and specific nutrient content. An important advantage of using sugar beet molasses as a hypertonic solution is an enrichment of the dehydrated material in minerals and vitamins, which penetrate from molasses into the plant tissue. Concentration of sugar beet molasses solution and immersion time had the biggest influence on the process of osmotic dehydration of fruit and vegetables, while the temperature of the solution was the least influential parameter. The effect of immersion time on the kinetics of osmotic dehydration in sugar beet molasses increases with an increase in concentration of hypertonic solution. Fruit and vegetables dehydrated in sugar beet molasses had a higher dry matter content compared to samples treated in sucrose solutions. Besides, application of sugar beet molasses in osmotic dehydration of fruits and vegetables had some other advantages such as lower cost of molasses compared to sugar and its liquid aggregate

Fatal cerebral edema and intracranial hemorrhage associated with hypernatremic dehydration

International Nuclear Information System (INIS)

Mocharla, R.; Schexnayder, S.M.; Glasier, C.M.

1997-01-01

We report neuroimaging findings of intracranial hemorrhage and cerebral edema in an infant with obtundation and seizures, initially suspected to be secondary to non-accidental trauma but finally attributed to hypernatremic dehydration. Neuroimaging findings due to hypernatremic dehydration have not been previously described in the radiologic literature. Hypernatremia should be included in the differential diagnosis of intracranial hemorrhage in the infant without evidence of nonaccidental trauma. (orig.). With 1 fig

Inactivation of Enterobacter sakazakii of dehydrated infant formula by gamma-irradiation

International Nuclear Information System (INIS)

Lee, Ju-Woon; Oh, Sang-Hee; Byun, Eui-Baek; Kim, Jae-Hun; Kim, Jang-Ho; Woon, Jae-Ho; Byun, Myung-Woo

2007-01-01

Enterobacter sakazakii has been implicated as a causal organism in a severe form of neonatal meningitis, with reported mortality rates of 20%. The population at greatest risk is immunocompromised infants of any age. Dried infant formula has been identified as a potential source of the organism in both outbreaks and sporadic cases. The objective of this study was to investigate theirradiation effect of the inactivation on E. sakazakii (ATCC 29544) of a dehydrated infant formula. The D 10 -values were 0.22-0.27 and 0.76 kGy for broth and dehydrated infant formula, respectively. The irradiation at 5.0 kGy was able to completely eliminate the E. sakazakii inoculated at 8.0 to 9.0 log CFU g -1 onto a dehydrated infant formula. There was no regrowth for all samples during the time they were stored at 10 deg. C for 6 h after rehydration. The present results indicated that a gamma-irradiation could potentially be used to inactivate E. sakazakii in a dehydrated powdered infant formula

Inactivation of Enterobacter sakazakii of dehydrated infant formula by gamma-irradiation

Energy Technology Data Exchange (ETDEWEB)

Lee, Ju-Woon; Oh, Sang-Hee [Radiation Application Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580 185 (Korea, Republic of); Byun, Eui-Baek [Radiation Application Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580 185 (Korea, Republic of); Graduate School of Biotechnology, Korea University, Yeongi 339-700 (Korea, Republic of); Kim, Jae-Hun; Kim, Jang-Ho [Radiation Application Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580 185 (Korea, Republic of); Woon, Jae-Ho [Livestock Products standard Division, National Veterinary Research and Quarantine Service, Anyang 430-824 (Korea, Republic of); Byun, Myung-Woo [Radiation Application Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580 185 (Korea, Republic of)], E-mail: mwbyun@kaeri.re.kr

2007-11-15

Enterobacter sakazakii has been implicated as a causal organism in a severe form of neonatal meningitis, with reported mortality rates of 20%. The population at greatest risk is immunocompromised infants of any age. Dried infant formula has been identified as a potential source of the organism in both outbreaks and sporadic cases. The objective of this study was to investigate theirradiation effect of the inactivation on E. sakazakii (ATCC 29544) of a dehydrated infant formula. The D{sub 10}-values were 0.22-0.27 and 0.76 kGy for broth and dehydrated infant formula, respectively. The irradiation at 5.0 kGy was able to completely eliminate the E. sakazakii inoculated at 8.0 to 9.0 log CFU g{sup -1} onto a dehydrated infant formula. There was no regrowth for all samples during the time they were stored at 10 deg. C for 6 h after rehydration. The present results indicated that a gamma-irradiation could potentially be used to inactivate E. sakazakii in a dehydrated powdered infant formula.

Inactivation of Enterobacter sakazakii of dehydrated infant formula by gamma-irradiation

Science.gov (United States)

Lee, Ju-Woon; Oh, Sang-Hee; Byun, Eui-Baek; Kim, Jae-Hun; Kim, Jang-Ho; Woon, Jae-Ho; Byun, Myung-Woo

2007-11-01

Enterobacter sakazakii has been implicated as a causal organism in a severe form of neonatal meningitis, with reported mortality rates of 20%. The population at greatest risk is immunocompromised infants of any age. Dried infant formula has been identified as a potential source of the organism in both outbreaks and sporadic cases. The objective of this study was to investigate theirradiation effect of the inactivation on E. sakazakii (ATCC 29544) of a dehydrated infant formula. The D10-values were 0.22-0.27 and 0.76 kGy for broth and dehydrated infant formula, respectively. The irradiation at 5.0 kGy was able to completely eliminate the E. sakazakii inoculated at 8.0 to 9.0 log CFU g -1 onto a dehydrated infant formula. There was no regrowth for all samples during the time they were stored at 10 °C for 6 h after rehydration. The present results indicated that a gamma-irradiation could potentially be used to inactivate E. sakazakii in a dehydrated powdered infant formula.

Microwave-Enhanced Sulphated Zirconia and SZ/MCM-41 Catalyzed Regioselective Synthesis of β-Amino Alcohols Under Solvent-Free Conditions

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Eduardo González-Zamora

2008-04-01

Full Text Available A solvent-free approach for the regioselective synthesis of β-amino alcohols inshorter reaction times and higher yields, compared to conventional heating is described. Itinvolves microwave (MW exposure of undiluted reactants in the presence of sulphatedzirconia (SZ or sulphated zirconia over MCM-41 (SZM as catalyst. Both acid materialscan be easily recovered and reused.

Performance of clinical signs in the diagnosis of dehydration in children with acute gastroenteritis.

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Hoxha, Teuta; Xhelili, Luan; Azemi, Mehmedali; Avdiu, Muharrem; Ismaili-Jaha, Vlora; Efendija-Beqa, Urata; Grajcevci-Uka, Violeta

2015-02-01

Acute evaluation and treatment of children presenting with dehydration represent one of the most common situation in the pediatric emergency department. To identify dehydration in infants and children before treatment, a number of symptoms and clinical signs have been evaluated. The aim of the study was to describe the performance of clinical signs in detecting dehydration in children. Two hundred children aged 1 month to 5 year were involved in our prospective study. The clinical assessment consisted of the ten clinical signs of dehydration, including those recommended by WHO (World Health Organization), heart rate, and capillary refill time. Two hundred patients with diarrhea were enrolled in the study. The mean age was 15.62±9.03 months and 57.5% were male. Of these 121 had a fluid deficit of dehydration were found to have the following respective gains in percent weight at the end of illness: 2.44±0.3, 6.05± 1.01 and, 10.66± 0.28, respectively. All clinical signs were found more frequently with increasing amounts of dehydration(pdehydration (deficit dehydration (deficit 5% to 9%) was 6.5 and among those with severe dehydration (deficit >10%) the median was 9 (p<0.0001, Kruskal-Wallis test). Using stepwise linear regression and a p value of <0.05 for entry into the model, a four-variable model including sunken eyes, skin elasticity, week radial pulse, and general appearance was derived. None of the 10 findings studied, is sufficiently accurate to be used in isolation. When considered together, sunken eyes, decreased skin turgor, weak pulse and general appearance provide the best explanatory power of the physical signs considered.

Lea protein expression during cold-induced dehydration in the Arctic collembola Megaphorura arctica

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Popović Ž.D.

2011-01-01

Full Text Available The Arctic springtail Megaphorura arctica (Tullberg, 1876 employs a strategy known as cryoprotective dehydration to survive winter temperatures as low as -25°C. During cryoprotective dehydration, water is lost from the animal to ice in its surroundings as a result of the difference in vapour pressure between the animal’s supercooled body fluids and ice (Worland et al., 1998; Holmstrup and Somme, 1998. This mechanism ensures that as the habitat temperature falls, the concentration of solutes remains high enough to prevent freezing (Holmstrup et al., 2002. In M. arctica, accumulation of trehalose, a cryo/anhydro protectant, occurs in parallel with dehydration. Recent studies have identified a number of genes and cellular processes involved in cryoprotective dehydration in M. arctica (Clark et al., 2007; Clark et al., 2009; Purać et al., 2011. One of them includes late embryogenesis abundant (LEA proteins. This study, together with that of Bahrndorff et al. (2008, suggests that LEA proteins may be involved in protective dehydration in this species.

Sonographic aorta/IVC cross-sectional area index for evaluation of dehydration in children.

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Kwon, Hyuksool; Jung, Jae Yun; Lee, Jin Hee; Kwak, Young Ho; Kim, Do Kyun; Jung, Jin Hee; Chang, Ik Wan; Kim, Kyuseok

2016-09-01

Current studies have not found sufficient evidence to encourage the use of ultrasound for assessing dehydration in children. We introduce a new sonographic parameter, the "aorta/inferior vena cava (IVC) cross-sectional area index" (Ao/IVCA) measured just inferior to the xiphoid process, for the effective evaluation of dehydration in children. This is a prospective, observational study. We enrolled children who presented to the pediatric emergency department (PED) between May 2014 and January 2015. We measured the maximum diameter of the aorta from inner wall to inner wall, and the long and short axis diameters of IVC using a convex array transducer. Ao/IVCA was calculated and compared with aorta/IVC maximal diameter index (Ao/IVCD) and the clinical dehydration scale (CDS). A total of 34 children were enrolled. We found a statistically significant correlation between Ao/IVCA and CDS (R(2) = 0.30; P dehydration. The diagnostic performance of Ao/IVCA for dehydration might be higher than that of the method that uses the maximum diameter of IVC and the aorta. Copyright © 2016 Elsevier Inc. All rights reserved.

Novel Fragmentation Pathways of Anionic Adducts of Steroids Formed by Electrospray Anion Attachment Involving Regioselective Attachment, Regiospecific Decompositions, Charge-Induced Pathways, and Ion-Dipole Complex Intermediates

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Rannulu, Nalaka S.; Cole, Richard B.

2012-09-01

The analysis of several bifunctional neutral steroids, 5-α-pregnane diol (5-α-pregnane-3α-20βdiol), estradiol (3,17α-dihydroxy-1,3,5(10)-estratriene), progesterone (4-pregnene-3,20-dione), lupeol (3β-hydroxy-20(29)-lupene), pregnenolone (5-pregnen-3β-ol-20-one), and pregnenolone acetate (5-pregnen-3β-ol-20-one acetate) was accomplished by negative ion electrospray mass spectrometry (ESI-MS) employing adduct formation with various anions: fluoride, bicarbonate, acetate, and chloride. Fluoride yielded higher abundances of anionic adducts and more substantial abundances of deprotonated molecules compared with other investigated anions. Collision-induced dissociation (CID) of precursor [M + anion]- adducts of these steroids revealed that fluoride adduct [M + F]- precursors first lose HF to produce [M - H]- and then undergo consecutive decompositions to yield higher abundances of structurally-informative product ions than the other tested anions. In addition to charge-remote fragmentations, the majority of CID pathways of estradiol are deduced to occur via charge-induced fragmentation. Most interestingly, certain anions exhibit preferential attachment to a specific site on these bifunctional steroid molecules, which we are calling "regioselective anion attachment." Regioselective anion attachment is evidenced by subsequent regiospecific decomposition. Regioselective attachment of fluoride (and acetate) anions to low (and moderate) acidity functional groups of pregnenolone, respectively, is demonstrated using deuterated compounds. Moreover, the formation of unique intermediate ion-dipole complexes leading to novel fragmentation pathways of fluoride adducts of pregnenolone acetate, and bicarbonate adducts of d4-pregnenolone, are also discussed.

Dehydration stress memory genes of Zea mays; comparison with Arabidopsis thaliana

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2014-01-01

Background Pre-exposing plants to diverse abiotic stresses may alter their physiological and transcriptional responses to a subsequent stress, suggesting a form of “stress memory”. Arabidopsis thaliana plants that have experienced multiple exposures to dehydration stress display transcriptional behavior suggesting “memory” from an earlier stress. Genes that respond to a first stress by up-regulating or down-regulating their transcription but in a subsequent stress provide a significantly different response define the ‘memory genes’ category. Genes responding similarly to each stress form the ‘non-memory’ category. It is unknown whether such memory responses exists in other Angiosperm lineages and whether memory is an evolutionarily conserved response to repeated dehydration stresses. Results Here, we determine the transcriptional responses of maize (Zea mays L.) plants that have experienced repeated exposures to dehydration stress in comparison with plants encountering the stress for the first time. Four distinct transcription memory response patterns similar to those displayed by A. thaliana were revealed. The most important contribution is the evidence that monocot and eudicot plants, two lineages that have diverged 140 to 200 M years ago, display similar abilities to ‘remember’ a dehydration stress and to modify their transcriptional responses, accordingly. The highly sensitive RNA-Seq analyses allowed to identify genes that function similarly in the two lineages, as well as genes that function in species-specific ways. Memory transcription patterns indicate that the transcriptional behavior of responding genes under repeated stresses is different from the behavior during an initial dehydration stress, suggesting that stress memory is a complex phenotype resulting from coordinated responses of multiple signaling pathways. Conclusions Structurally related genes displaying the same memory responses in the two species would suggest conservation

Effects of dehydration methods on quality characteristics of yellow passion fruit co-products.

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Silva, Neiton C; Duarte, Claudio R; Barrozo, Marcos As

2017-11-01

The production and processing of fruits generate a large amount of residues, which are usually disposed of or under-used, representing losses of raw material and energy. The present paper investigates the effect of four dehydration techniques (convective, infrared, microwave and freeze-drying) on yellow passion fruit (Passiflora edulis f. flavicarpa) co-products and the influence of the main variables on moisture removal and bioactive compounds. The compounds analyzed were total phenolics, total flavonoids, ascorbic acid and pectin. The content of phenolics and flavonoids increased after dehydration in all techniques investigated and the process temperatures directly affected the ascorbic acid content. Microwave dehydration showed the best results for most bioactive compounds analyzed, if performed in suitable process conditions. However, the highest levels of pectin content were obtained by freeze-drying and convective dehydration. This study reinforces the importance of the adequate use of passion fruit co-products due to the high levels of bioactive compounds in this material. Microwave dehydration presented the best results, which indicates the potential use of this technique for a better exploitation of fruit co-products. Larger quantities of pectin were extracted from samples dehydrated through methodologies with long-time process and low temperatures, such as convective drying and freeze-drying. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Proteomics approach to identify dehydration responsive nuclear proteins from chickpea (Cicer arietinum L.).

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Pandey, Aarti; Chakraborty, Subhra; Datta, Asis; Chakraborty, Niranjan

2008-01-01

Dehydration or water-deficit is one of the most important environmental stress factors that greatly influences plant growth and development and limits crop productivity. Plants respond and adapt to such stress by altering their cellular metabolism and activating various defense machineries. Mechanisms that operate signal perception, transduction, and downstream regulatory events provide valuable information about the underlying pathways involved in environmental stress responses. The nuclear proteins constitute a highly organized, complex network that plays diverse roles during cellular development and other physiological processes. To gain a better understanding of dehydration response in plants, we have developed a comparative nuclear proteome in a food legume, chickpea (Cicer arietinum L.). Three-week-old chickpea seedlings were subjected to progressive dehydration by withdrawing water and the changes in the nuclear proteome were examined using two-dimensional gel electrophoresis. Approximately 205 protein spots were found to be differentially regulated under dehydration. Mass spectrometry analysis allowed the identification of 147 differentially expressed proteins, presumably involved in a variety of functions including gene transcription and replication, molecular chaperones, cell signaling, and chromatin remodeling. The dehydration responsive nuclear proteome of chickpea revealed a coordinated response, which involves both the regulatory as well as the functional proteins. This study, for the first time, provides an insight into the complex metabolic network operating in the nucleus during dehydration.

DEHYDRATION OF CHEESE BY HOT AIR, MICROWAVE AND FREEZE-DRYING

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ANA RITA C. PINHO

2017-12-01

Full Text Available The objective of this work was to study the dehydration of skim cheese through different methods, in particular by hot air, microwave and freeze-drying, in order to assess which of these methods would be more suitable for the development of a new product (cheese snack. For the three processes of dehydration, several temperatures, powers and times were used, respectively. The drying time was optimized to allow the water activity of the final product to be between 0.3 and 0.4. The color and texture of the product obtained by the three processes were evaluated, and the nutritional analysis (protein, lipids, ash of the product dried by hot air at 52 ºC and by microwave at 750 W and 850 W was performed. The sensory analysis of the microwave dehydrated products was also carried out. The results obtained revealed that the temperature played a relevant role in the drying time and the hardness of the product. In the dehydration by microwave, the power of 850 W resulted in a lower drying time and a better color preservation, but in a high hardness of the samples. Among the three processes studied, the microwave drying was the fastest for the water removal from the cheese.

Charts for weight loss to detect hypernatremic dehydration and prevent formula supplementing.

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van Dommelen, Paula; Boer, Suzanne; Unal, Sevim; van Wouwe, Jacobus P

2014-06-01

Most breast-fed newborns get the milk they need. However, very rarely milk intake is insufficient mostly as a result of poor breastfeeding techniques. Dramatic weight loss and hypernatremic dehydration may occur. Our aim was to construct charts for weight loss. A case-control study was performed. Charts with standard deviation score (SDS) lines for weight loss in the first month were constructed for 2,359 healthy breast-fed term newborns and 271 cases with breastfeeding-associated hypernatremic dehydration with serum sodium level > 149 mEq/L. Day 0 was defined as the day of birth. Many cases with (or who will develop) hypernatremic dehydration (84%; +1 SDS line) fell below the -1 SDS line at day 3, the -2 SDS line at day 4, and the -2.5 SDS line at day 5 in the chart of the healthy breast-fed newborns. Weight loss of cases with permanent residual symptoms was far below the -2.5 SDS. Already at an early age, weight loss differs between healthy breast-fed newborns and those with hypernatremic dehydration. Charts for weight loss are, therefore, useful tools to detect early, or prevent newborns from developing, breastfeeding-associated hypernatremic dehydration, and also to prevent unnecessary formula supplementing. © 2014 Wiley Periodicals, Inc.

The value of body weight measurement to assess dehydration in children.

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Pruvost, Isabelle; Dubos, François; Chazard, Emmanuel; Hue, Valérie; Duhamel, Alain; Martinot, Alain

2013-01-01

Dehydration secondary to gastroenteritis is one of the most common reasons for office visits and hospital admissions. The indicator most commonly used to estimate dehydration status is acute weight loss. Post-illness weight gain is considered as the gold-standard to determine the true level of dehydration and is widely used to estimate weight loss in research. To determine the value of post-illness weight gain as a gold standard for acute dehydration, we conducted a prospective cohort study in which 293 children, aged 1 month to 2 years, with acute diarrhea were followed for 7 days during a 3-year period. The main outcome measures were an accurate pre-illness weight (if available within 8 days before the diarrhea), post-illness weight, and theoretical weight (predicted from the child's individual growth chart). Post-illness weight was measured for 231 (79%) and both theoretical and post-illness weights were obtained for 111 (39%). Only 62 (21%) had an accurate pre-illness weight. The correlation between post-illness and theoretical weight was excellent (0.978), but bootstrapped linear regression analysis showed that post-illness weight underestimated theoretical weight by 0.48 kg (95% CI: 0.06-0.79, pdehydration according to post-illness weight (21%) was significantly lower than the prevalence estimated by either theoretical weight (60%) or clinical assessment (66%, pdehydration. The performance of dehydration signs or scales determined by using post-illness weight as a gold standard has to be reconsidered.

Dehydration Process of Hofmann-Type Layered Solids

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Edilso Reguera

2013-04-01

Full Text Available In the present work the dehydration process of layered solids with formula unit M(H2O2[Ni(CN4]·nH2O, M = Ni, Co, Mn; n = 1, 2, 4 is studied using modulated thermogravimetry. The results show that water molecules need to overcome an energetic barrier (activation energy between 63 and 500 kJ/mol in order to diffuse through the interlayer region. The related kinetic parameters show a dependence on the water partial pressure. On the other hand, X-ray diffraction results provide evidence that the dehydration process is accompanied by framework collapse, limiting the structural reversibility, except for heating below 80 °C where the ordered structure remains. Removal of water molecules from the interlayer region disrupts the long-range structural order of the solid.

Analysis of dehydration and strength in elite badminton players.

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Abián-Vicén, Javier; Del Coso, Juan; González-Millán, Cristina; Salinero, Juan José; Abián, Pablo

2012-01-01

The negative effects of dehydration on aerobic activities are well established. However, it is unknown how dehydration affects intermittent sports performance. The purpose of this study was to identify the level of dehydration in elite badminton players and its relation to muscle strength and power production. Seventy matches from the National Spanish badminton championship were analyzed (46 men's singles and 24 women's singles). Before and after each match, jump height and power production were determined during a countermovement jump on a force platform. Participants' body weight and a urine sample were also obtained before and after each match. The amount of liquid that the players drank during the match was also calculated by weighing their individual drinking bottles. Sweat rate during the game was 1.14 ± 0.46 l/h in men and 1.02 ± 0.64 l/h in women. The players rehydrated at a rate of 1.10 ± 0.55 l/h and 1.01 ± 0.44 l/h in the male and female groups respectively. Thus, the dehydration attained during the game was only 0.37 ± 0.50% in men and 0.32 ± 0.83% in women. No differences were found in any of the parameters analyzed during the vertical jump (men: from 31.82 ± 5.29 to 32.90 ± 4.49 W/kg; p>0.05, women: from 26.36 ± 4.73 to 27.25 ± 4.44 W/kg; p>0.05). Post-exercise urine samples revealed proteinuria (60.9% of cases in men and 66.7% in women), leukocyturia (men = 43.5% and women = 50.0%) and erythrocyturia (men = 50.0% and women = 21.7%). Despite a moderate sweat rate, badminton players adequately hydrated during a game and thus the dehydration attained was low. The badminton match did not cause muscle fatigue but it significantly increased the prevalence of proteinuria, leukocyturia and erythrocyturia.

Analysis of dehydration and strength in elite badminton players.

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Javier Abián-Vicén

Full Text Available BACKGROUND: The negative effects of dehydration on aerobic activities are well established. However, it is unknown how dehydration affects intermittent sports performance. The purpose of this study was to identify the level of dehydration in elite badminton players and its relation to muscle strength and power production. METHODOLOGY: Seventy matches from the National Spanish badminton championship were analyzed (46 men's singles and 24 women's singles. Before and after each match, jump height and power production were determined during a countermovement jump on a force platform. Participants' body weight and a urine sample were also obtained before and after each match. The amount of liquid that the players drank during the match was also calculated by weighing their individual drinking bottles. RESULTS AND DISCUSSION: Sweat rate during the game was 1.14 ± 0.46 l/h in men and 1.02 ± 0.64 l/h in women. The players rehydrated at a rate of 1.10 ± 0.55 l/h and 1.01 ± 0.44 l/h in the male and female groups respectively. Thus, the dehydration attained during the game was only 0.37 ± 0.50% in men and 0.32 ± 0.83% in women. No differences were found in any of the parameters analyzed during the vertical jump (men: from 31.82 ± 5.29 to 32.90 ± 4.49 W/kg; p>0.05, women: from 26.36 ± 4.73 to 27.25 ± 4.44 W/kg; p>0.05. Post-exercise urine samples revealed proteinuria (60.9% of cases in men and 66.7% in women, leukocyturia (men = 43.5% and women = 50.0% and erythrocyturia (men = 50.0% and women = 21.7%. CONCLUSIONS: Despite a moderate sweat rate, badminton players adequately hydrated during a game and thus the dehydration attained was low. The badminton match did not cause muscle fatigue but it significantly increased the prevalence of proteinuria, leukocyturia and erythrocyturia.

Dehydration-driven topotaxy in subduction zones

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Padrón-Navarta, José Alberto; Tommasi, Andréa; Garrido, Carlos J.

2014-05-01

Mineral replacement reactions play a fundamental role in the chemistry and the strength of the lithosphere. When externally or internally derived fluids are present, interface-coupled dissolution-precipitation is the driving mechanism for such reactions [1]. One of the microstructural features of this process is a 3D arrangement of crystallographic axes across internal interfaces (topotaxy) between reactant and product phases. Dehydration reactions are a special case of mineral replacement reaction that generates a transient fluid-filled porosity. Among others, the dehydration serpentinite is of special relevance in subduction zones because of the amount of fluids involved (potentially up to 13 wt.%). Two topotatic relationships between olivine and antigorite (the serpentine mineral stable at high temperature and pressure) have been reported in partially hydrated mantle wedge xenoliths [2]. Therefore, if precursor antigorite serpentine has a strong crystallographic preferred orientation (CPO) its dehydration might result in prograde peridotite with a strong inherited CPO. However for predicting the importance of topotactic reactions for seismic anisotropy of subduction zones we also need to consider the crystallization orthopyroxene + chlorite in the prograde reaction and, more importantly, the fact that this dehydration reaction produces a transient porosity of ca. 20 % vol. that results in local fluctuations of strain during compaction and fluid migration. We address this issue by a microstructural comparison between the CPO developed in olivine, orthopyroxene and chlorite during high-pressure antigorite dehydration in piston cylinder experiments (at 750ºC and 20 kbar and 1000ºC and 30 kbar, 168 h) and that recorded in natural samples (Cerro del Almirez, Betic Cordillera, Spain). Experimentally developed CPOs are strong. Prograde minerals show a significant inheritance of the former antigorite foliation. Topotactic relations are dominated by (001)atg//(100)ol

Evaluation of the quality of hot air dehydrated onion coming from gamma radiated bulbs

International Nuclear Information System (INIS)

Elman, L.; Pezzutti, A.; Croci, C.A.

2003-01-01

The purpose of this work was to evaluate the quality of hot air dehydrated onion, as regards physical and chemical characteristics, coming from the regional product that was gamma irradiated for sprout inhibition. We worked with the onion variety Valenciana Sintetica 14. Radio inhibition was made 30 days post harvest with gamma radiation from a 60 Co source at the Centro Atomico Ezeiza-CNEA, using a dose of 60 Gy. The skin of the bulbs was manually removed and the bulbs were cut in pieces 3 mm thick and between 1 and 3 cm long. The material was dehydrated in a rotating dryer with forced air circulation at 60 C degrees, between 0.8 and 1.7 m/s air speed and at ambient relative humidity. Dehydration was made 80 days after post-irradiation. The quality of the dehydrated onion was evaluated by the following physical- chemical analysis: total solids content, pungency (indirectly measured by pyruvic acid content assessment), color, pH, carbon hydrates and sensorial analysis. All analytical determinations were made in triplicate. The results obtained showed there are no significant changes between the averages of the physical-chemical properties of the control dehydrated samples and those coming from the radio-inhibited raw matter. According to the sensorial analysis, only the color of dehydrated onion was affected by the radio inhibition process. However, and according to the panel members comment, the greatest browning degree observed in ionizing radiation treated onion seemed to result more attractive to them. It may be concluded that radio inhibited regional onion can be useful as raw matter for hot air dehydrated product. It must be remarked that its use would extend the product use by dehydration plants, thus implying an increase of their processing capacity with the corresponding financial benefit. (author)

Thiophene fused azacoronenes: regioselective synthesis, self organization, charge transport, and its incorporation in conjugated polymers

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Liu, Yi; He, Bo

2015-09-15

A regioselective synthesis of an azacoronene fused with two peripheral thiophene groups has been realized through a concise synthetic route. The resulting thienoazacoronene (TAC) derivatives show high degree of self-organization in solution, in single crystals, in the bulk, and in spuncast thin films. Spuncast thin film field-effect transistors of the TACs exhibited mobilities up to 0.028 cm.sup.2V.sup.-1 S.sup.-1, which is among the top field effect mobilities for solution processed discotic materials. Organic photovoltaic devices using TAC-containing conjugated polymers as the donor material exhibited a high open-circuit voltage of 0.89 V, which was ascribable to TAC's low-lying highest occupied molecular orbital energy level.

HYPERGLYCEMIA IN GRADE III AND GRADE IV MALNUTRITION WITH DEHYDRATING GASTROENTERITIS

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Mallesh

2015-07-01

Full Text Available OBJECTIVE OF THE STUDY: To study the incidence of hyperglycemia in grade III AND IV malnutrition with no signs and some signs of dehydration. SETTING: Tertiary care center located in north Karnataka. DESIGN: Prospective observational study involving 21 children. METHODS: All the children with grade III and grade IV malnutrition presenting with diarrhea of less than 14 days duration, having no signs to some signs of dehydration. RESULTS: Hyperglycemia was observed in three of 21 children hypoglycemia was observed in six children. CONCLUSION: Although hypoglycemia is common finding in moderate and severely malnourished children with dehydrating gastroenteritis, hyperglycemia should also be suspected and treated. Long term follow up of these children is needed involving larger number of people in multicenter studies.

Dehydration/hydration of granular beds for thermal storage applications: a combined NMR and temperature study

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Donkers, P.A.J.; Pel, L.; Adan, O.C.G.

For heat/cold storage systems a granular bed of salt hydrates is studied during dehydration/hydration. The water density in these beds are measured with help of NMR. Diffusion based dehydration of a granular bed of Na2SO4·10H2O is shown to be internally limited as larger grains dehydrate faster than

Effect of dehydration on the development of collaterals in acute middle cerebral artery occlusion.

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Chang, S-W; Huang, Y-C; Lin, L-C; Yang, J-T; Weng, H-H; Tsai, Y-H; Lee, T-H

2016-03-01

Recent large series studies have demonstrated that dehydration is common amongst stroke subjects and is associated with poor outcome. However, the effects of hydration status on the development of collaterals have never been discussed. In this study, the hypothesis that hydration status is an important factor for developing collaterals after acute middle cerebral artery (MCA) infarction was tested. Eighty-seven patients with acute infarction due to occlusion of the MCA were enrolled. Two collateral markers, posterior cerebral artery (PCA) laterality and fluid-attenuated inversion recovery hyperintense vessels (HVs) were assessed from magnetic resonance imaging. Dehydration status was defined by a nitrogen to creatinine ratio ≧ of 15. The associations between dehydration status and the development of collaterals were estimated. Sixty-one of 87 patients (70.1%) were identified as dehydrated. The development of PCA laterality and HVs shows a significant difference between dehydrated and euhydrated patients. A serum nitrogen to creatinine ratio Dehydration remained an independent negative predictor for the development of PCA laterality and HVs in the multivariate analysis. Hydration status is associated with the development of collateral flow after acute MCA occlusion. This preliminary study provides an imaging clue that hydration status and early hydration therapy could be important for acute stroke management. © 2016 EAN.

ATG18 and FAB1 are involved in dehydration stress tolerance in Saccharomyces cerevisiae.

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López-Martínez, Gema; Margalef-Català, Mar; Salinas, Francisco; Liti, Gianni; Cordero-Otero, Ricardo

2015-01-01

Recently, different dehydration-based technologies have been evaluated for the purpose of cell and tissue preservation. Although some early results have been promising, they have not satisfied the requirements for large-scale applications. The long experience of using quantitative trait loci (QTLs) with the yeast Saccharomyces cerevisiae has proven to be a good model organism for studying the link between complex phenotypes and DNA variations. Here, we use QTL analysis as a tool for identifying the specific yeast traits involved in dehydration stress tolerance. Three hybrids obtained from stable haploids and sequenced in the Saccharomyces Genome Resequencing Project showed intermediate dehydration tolerance in most cases. The dehydration resistance trait of 96 segregants from each hybrid was quantified. A smooth, continuous distribution of the anhydrobiosis tolerance trait was found, suggesting that this trait is determined by multiple QTLs. Therefore, we carried out a QTL analysis to identify the determinants of this dehydration tolerance trait at the genomic level. Among the genes identified after reciprocal hemizygosity assays, RSM22, ATG18 and DBR1 had not been referenced in previous studies. We report new phenotypes for these genes using a previously validated test. Finally, our data illustrates the power of this approach in the investigation of the complex cell dehydration phenotype.

ATG18 and FAB1 are involved in dehydration stress tolerance in Saccharomyces cerevisiae.

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Gema López-Martínez

Full Text Available Recently, different dehydration-based technologies have been evaluated for the purpose of cell and tissue preservation. Although some early results have been promising, they have not satisfied the requirements for large-scale applications. The long experience of using quantitative trait loci (QTLs with the yeast Saccharomyces cerevisiae has proven to be a good model organism for studying the link between complex phenotypes and DNA variations. Here, we use QTL analysis as a tool for identifying the specific yeast traits involved in dehydration stress tolerance. Three hybrids obtained from stable haploids and sequenced in the Saccharomyces Genome Resequencing Project showed intermediate dehydration tolerance in most cases. The dehydration resistance trait of 96 segregants from each hybrid was quantified. A smooth, continuous distribution of the anhydrobiosis tolerance trait was found, suggesting that this trait is determined by multiple QTLs. Therefore, we carried out a QTL analysis to identify the determinants of this dehydration tolerance trait at the genomic level. Among the genes identified after reciprocal hemizygosity assays, RSM22, ATG18 and DBR1 had not been referenced in previous studies. We report new phenotypes for these genes using a previously validated test. Finally, our data illustrates the power of this approach in the investigation of the complex cell dehydration phenotype.

Assessing Dehydration Employing End-Tidal Carbon Dioxide in Children With Vomiting and Diarrhea.

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Freedman, Stephen B; Johnson, David W; Nettel-Aguirre, Alberto; Mikrogianakis, Angelo; Williamson-Urquhart, Sarah; Monfries, Nicholas; Cheng, Adam

2017-05-23

Serum bicarbonate reflects dehydration severity in children with gastroenteritis. Previous work in children receiving intravenous rehydration has correlated end-tidal carbon dioxide (EtCO2) with serum bicarbonate. We evaluated whether EtCO2 predicts weight change in children with vomiting and/or diarrhea. A prospective cohort study was conducted. Eligible children were 3 months to 10 years old and presented for emergency department (ED) care because of vomiting and/or diarrhea. End-tidal carbon dioxide measurements were performed after triage. The diagnostic standard was weight change determined from serial measurements after symptom resolution. A receiver operating characteristic curve was constructed to identify a cut-point to predict 5% or more dehydration. In total, 195 children were enrolled. Among the 169 (87%) with EtCO2 measurements, the median (interquartile range [IQR]) was 30.4 (27.8 to 33.1). One hundred fifty-eight had repeat weights performed at home; the median (IQR) weight change from ED presentation to well weight was +0.06 (-0.14 to +0.30) or +0.72% (-1.2% to +2.1%). Sixteen percent (25/158) had 3% or more and 4% (6/158) had 5% or more weight gain (ie, percent dehydration). One hundred sixteen (60%) completed home follow-up and had acceptable EtCO2 recordings. Receiver operating curve analysis revealed an area under the curve of 0.34 (95% confidence interval, 0.06 to 0.62) for EtCO2 as a predictor of 5% or more dehydration. The limited accuracy of EtCO2 measurement to predict 5% or more dehydration precludes its use as a tool to assess dehydration severity in children. End-tidal carbon dioxide monitoring does not have the ability to identify those children with 5% or more dehydration in a cohort of children with vomiting and/or diarrhea presenting for ED care.

Dehydration kinetics of talc and 10 Å phase: Consequences for subduction zone seismicity

Science.gov (United States)

Chollet, Mélanie; Daniel, Isabelle; Koga, Kenneth T.; Petitgirard, Sylvain; Morard, Guillaume

2009-06-01

The process of dehydration embrittlement is usually proposed as an explanation for the presence of intermediate-depth earthquakes in subduction zones. It assumes that the release of water by hydrous mineral breakdown is fast enough to provoke brittle failure. We performed high-pressure, high-temperature, dehydration experiments of talc and 10 Å phase coupled with in situ measurement of reaction kinetics using synchrotron X-ray diffraction. Newly developed, X-ray transparent, pressure-sealed, titanium capsule ensured a closed thermochemical environment. From isothermal kinetics data fitted to the Avrami's equation and from the texture of reaction products, we conclude that dehydration rates of these minerals are limited by diffusion. Predicted minimum rates of fluid release range from 10 - 4 to 9 × 10 - 6 m 3fluid m - 3 rock s - 1 , and are fast enough to provoke hydraulic rupture since Maxwell relaxation rate of rocks relevant of subduction zones are slower than the rate of fluid release. These rates are comparable between talc, 10 Å phase and antigorite also [Perrillat, J.-P., Daniel, I., Koga, K.T., Reynard, B., Cardon, H., Crichton, W.A., 2005. Kinetics of antigorite dehydration: a real-time X-ray diffraction study. Earth Planet. Sci. Lett. 236, 899-913]. Consequently, we suggest that the dehydration of hydrous minerals may eventually be fast enough to trigger the intermediate-depth earthquakes, and that the deepest among intermediate-depth earthquakes may actually locate the limits for dehydration of hydrous minerals in the downgoing lithosphere.

Dehydration of Older Patients in Institutional Care and the Home Environment.

Science.gov (United States)

Lešnik, Amadeus; Piko, Nejc; Železnik, Danica; Bevc, Sebastjan

2017-11-01

Dehydration in older adults is an important clinical problem associated with more comorbidities, longer hospital stays, and higher mortality rates. However, in daily clinical practice, no single gold standard marker of hydration status in older adults is available. The aim of the current study was to define the fluid balance status in older adults residing in institutional care or the home. Four hundred ten patients (192 from institutional care and 218 from home care) 65 and older from the region of lower Styria (Slovenia) were included in the study. Serum osmolality, electrolytes, and blood urea nitrogen to creatinine (BUN:Cr) ratio were used to identify dehydration. Statistically significant differences were found between groups in serum osmolality and BUN:Cr ratio. Moreover, dehydration (defined as increased serum osmolality) was significantly more common in patients in institutional care than home care (51% versus 41.3%, respectively). The results confirm that dehydration is a common clinical problem in older adults, especially in those from institutional care. Although many methods of determining hydration status in older adults have been proposed, no gold standard exists, making hydration evaluation difficult in this population. [Res Gerontol Nurs. 2017; 10(6):260-266.]. Copyright 2017, SLACK Incorporated.

Neonatal dehydrering (tørstefeber) hos nyfødte børn

DEFF Research Database (Denmark)

Zachariassen, Gitte; Juvonen, Pekka

2002-01-01

The aim was to identify characteristics in infants suffering from dehydration caused by breast-feeding malnutrition over a period of 21 months in South Denmark.......The aim was to identify characteristics in infants suffering from dehydration caused by breast-feeding malnutrition over a period of 21 months in South Denmark....

HIGH PERMEABILITY MEMBRANES FOR THE DEHYDRATION OF LOW WATER CONTENT ETHANOL BY PERVAPORATION

Science.gov (United States)

Energy efficient dehydration of low water content ethanol is a challenge for the sustainable production of fuel-grade ethanol. Pervaporative membrane dehydration using a recently developed hydrophilic polymer membrane formulation consisting of a cross-linked mixture of poly(allyl...

Diagnosing clinically significant dehydration in children with acute gastroenteritis using noninvasive methods: a meta-analysis.

Science.gov (United States)

Freedman, Stephen B; Vandermeer, Ben; Milne, Andrea; Hartling, Lisa

2015-04-01

To determine the most accurate, noninvasive method of assessing dehydration. The following data sources were searched: electronic databases, gray literature, scientific meetings, reference lists, and authors of unpublished studies. Eligible studies were comparative outpatient evaluations that used an accepted reference standard and were conducted in developed countries in children aged Dehydration Scale (CDS), the "Gorelick" score, and unstructured physician assessment were evaluated in 3, 2, and 5 studies, respectively. Bedside ultrasound, capillary digital videography, and urinary measurements were each evaluated in one study. The CDS had a positive likelihood ratio (LR) range of 1.87-11.79 and a negative LR range of 0.30-0.71 to predict 6% dehydration. When combined with the 4-item Gorelick Score, the positive LR was 1.93 (95% CI 1.07-3.49) and negative LR was of 0.40 (95% CI 0.24-0.68). Unstructured dehydration assessment had a pooled positive LR of 2.13 (95% CI 1.33-3.44) and negative LR of 0.48 (95% CI 0.28-0.82) to detect ≥ 5% dehydration. Overall, the clinical scales evaluated provide some improved diagnostic accuracy. However, test characteristics indicate that their ability to identify children both with and without dehydration is suboptimal. Current evidence does not support the routine use of ultrasound or urinalysis to determine dehydration severity. Copyright © 2015 Elsevier Inc. All rights reserved.

Building blocks for the solution phase synthesis of oligonucleotides: regioselective hydrolysis of 3',5'-Di-O-levulinylnucleosides using an enzymatic approach.

Science.gov (United States)

García, Javier; Fernández, Susana; Ferrero, Miguel; Sanghvi, Yogesh S; Gotor, Vicente

2002-06-28

A short and convenient synthesis of 3'- and 5'-O-levulinyl-2'-deoxynucleosides has been developed from the corresponding 3',5'-di-O-levulinyl derivatives by regioselective enzymatic hydrolysis, avoiding several tedious chemical protection/deprotection steps. Thus, Candida antartica lipase B (CAL-B) was found to selectively hydrolyze the 5'-levulinate esters, furnishing 3'-O-levulinyl-2'-deoxynucleosides 3 in >80% isolated yields. On the other hand, immobilized Pseudomonas cepacia lipase (PSL-C) and Candida antarctica lipase A (CAL-A) exhibit the opposite selectivity toward the hydrolysis at the 3'-position, affording 5'-O-levulinyl derivatives 4 in >70% yields. A similar hydrolysis procedure was successfully extended to the synthesis of 3'- and 5'-O-levulinyl-protected 2'-O-alkylribonucleosides 7 and 8. This work demonstrates for the first time application of commercial CAL-B and PSL-C toward regioselective hydrolysis of levulinyl esters with excellent selectivity and yields. It is noteworthy that protected cytidine and adenosine base derivatives were not adequate substrates for the enzymatic hydrolysis with CAL-B, whereas PSL-C was able to accommodate protected bases during selective hydrolysis. In addition, we report an improved synthesis of dilevulinyl esters using a polymer-bound carbodiimide as a replacement for dicyclohexylcarbodiimide (DCC), thus considerably simplifying the workup for esterification reactions.

Improving the diffraction of apoA-IV crystals through extreme dehydration

International Nuclear Information System (INIS)

Deng, Xiaodi; Davidson, W. Sean; Thompson, Thomas B.

2011-01-01

Apolipoprotein A-IV crystals consisted of a long unit-cell edge (540 Å) with a high mosaic spread, making them intractable for X-ray diffraction analysis. Extreme dehydration in 60% PEG 3350 was utilized as a post-crystallization treatment as well a screening method to significantly sharpen the mosaic spread and increase the overall resolution of diffraction. Apolipoproteins are the protein component of high-density lipoproteins (HDL), which are necessary for mobilizing lipid-like molecules throughout the body. Apolipoproteins undergo self-association, especially at higher concentrations, making them difficult to crystallize. Here, the crystallization and diffraction of the core fragment of apolipoprotein A-IV (apoA-IV), consisting of residues 64–335, is presented. ApoA-IV 64–335 crystallized readily in a variety of hexagonal (P6) morphologies with similar unit-cell parameters, all containing a long axis of nearly 550 Å in length. Preliminary diffraction experiments with the different crystal morphologies all resulted in limited streaky diffraction to 3.5 Å resolution. Crystal dehydration was applied to the different morphologies with variable success and was also used as a quality indicator of crystal-growth conditions. The results show that the morphologies that withstood the most extreme dehydration conditions showed the greatest improvement in diffraction. One morphology in particular was able to withstand dehydration in 60% PEG 3350 for over 12 h, which resulted in well defined intensities to 2.7 Å resolution. These results suggest that the approach of integrating dehydration with variation in crystal-growth conditions might be a general technique to optimize diffraction

Survey of Clinical Evidence in Newborns with Hypernatremic Dehydration

Directory of Open Access Journals (Sweden)

Hasan Boskabadi

2016-01-01

Full Text Available Background & objectives: Weight loss and hypernatremic dehydration is a common problem in infants with inadequate nutrition. Determination of risk factors and clinical characteristics of these neonates may help to prevent or early detection of hypernatremia. This study designed to determine the prevalence of clinical signs and risk factors for hypernatremic dehydration. Methods: This study is a sectional descriptive study that conducted on 418 newborns during 1385 to 1393 AHS that referred to Ghaem hospital in Mashhad. The hypernatremic group consisted of 197 neonates with serum sodium level higher than 150 mg/dl and 221 isonatremic newborns with sodium level less than 150 mmol/L were included as controls. Both groups were compared in terms of clinical symptoms of dehydration and maternal risk factors. All data were recorded and coded. Data analysis performed using paired T test and chi square tests by SPSS 16 software. Results: In the present study, 2.8% of infants were hypernatremic. The most common symptoms were neonatal jaundice (62.2%, hyperthermia (25.8%, lethargy (23.6%, agitation (20.8 % and mucous membranes dryness (17.2%. Problems in pregnancy (p=0.002, inappropriate feeding techniques (p=0.000, the first lactation duration (p=0.022 and frequency per day (p=0.000 had statistically significant difference between case and control groups. Conclusion: Prevalence of hypernatremic dehydrationis considerable in our study and identifying the risk factors may help to reduce its incidence or exacerbation. Weight loss, especially in newborns having jaundice, hyperthermia and irritability, may be helpful in the early diagnosis of hypernatremic dehydration

Airway Surface Dehydration Aggravates Cigarette Smoke-Induced Hallmarks of COPD in Mice.

Science.gov (United States)

Seys, Leen J M; Verhamme, Fien M; Dupont, Lisa L; Desauter, Elke; Duerr, Julia; Seyhan Agircan, Ayca; Conickx, Griet; Joos, Guy F; Brusselle, Guy G; Mall, Marcus A; Bracke, Ken R

2015-01-01

Airway surface dehydration, caused by an imbalance between secretion and absorption of ions and fluid across the epithelium and/or increased epithelial mucin secretion, impairs mucociliary clearance. Recent evidence suggests that this mechanism may be implicated in chronic obstructive pulmonary disease (COPD). However, the role of airway surface dehydration in the pathogenesis of cigarette smoke (CS)-induced COPD remains unknown. We aimed to investigate in vivo the effect of airway surface dehydration on several CS-induced hallmarks of COPD in mice with airway-specific overexpression of the β-subunit of the epithelial Na⁺ channel (βENaC). βENaC-Tg mice and wild-type (WT) littermates were exposed to air or CS for 4 or 8 weeks. Pathological hallmarks of COPD, including goblet cell metaplasia, mucin expression, pulmonary inflammation, lymphoid follicles, emphysema and airway wall remodelling were determined and lung function was measured. Airway surface dehydration in βENaC-Tg mice aggravated CS-induced airway inflammation, mucin expression and destruction of alveolar walls and accelerated the formation of pulmonary lymphoid follicles. Moreover, lung function measurements demonstrated an increased compliance and total lung capacity and a lower resistance and hysteresis in βENaC-Tg mice, compared to WT mice. CS exposure further altered lung function measurements. We conclude that airway surface dehydration is a risk factor that aggravates CS-induced hallmarks of COPD.

Remedial technology for contaminated natural gas dehydrator sites

International Nuclear Information System (INIS)

Prosen, B.J.; Korreck, W.M.; Armstrong, J.M.

1991-01-01

Ground water and soil contamination at many of Michigan's oil and gas well sites has been attributed to natural gas dehydration processes. Since water was once thought to be the only by-product from the dehydration process, condensate from the process was discharged directly to the ground for several years. This condensate was later found to contain benzene, toluene, ethyl-benzene, and xylenes (BTEX), and the process of discharging condensate to the ground was stopped. Many oil and gas well sites had become impacted from the process during this time. Although condensate is no longer discharged to the ground, soil and water contamination still remains at many of these sites. In the last few years, the Michigan Department of Natural Resources has targeted over 90 well sites for assessment of contamination associated with gas dehydration. The results of many of these assessments indicate that soil and ground water have been impacted, and the State of Michigan has mandated cleanup of these sites. Remedial technologies which have been used to contain and/or clean up the sites include excavation and product removal, soil venting, purge and treat, and enhanced biodegradation. This paper is a discussion of the technology, implementation, and results from each of these methods

EPR study on gamma-irradiated fruits dehydrated via osmosis

International Nuclear Information System (INIS)

Yordanov, N.D.; Aleksieva, K.

2007-01-01

The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and γ-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas γ-irradiated exhibit 'sugar-like' EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples

EPR study on gamma-irradiated fruits dehydrated via osmosis

Science.gov (United States)

Yordanov, N. D.; Aleksieva, K.

2007-06-01

The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and γ-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas γ-irradiated exhibit "sugar-like" EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples.

Physicochemical characteristics of guava “Paluma” submitted to osmotic dehydration

OpenAIRE

Roselene Ferreira Oliveira; Lia Mara Moterlle; Edmar Clemente

2014-01-01

The aim of this work was to evaluate the conservation post process osmotic of guava stored temperature at 5oC. Guava (Psidium guajava L.), red variety “Paluma” minimally processed by mild osmotic dehydration, were packaged in polyethylene terephthalate (PET) and stored temperature at 5ºC. Non-treated guava, packed in PET trays, was used as control. The treatment used was osmotic dehydration in sucrose syrup at 60ºBrix and physicochemical determinations were pH, total soluble solids (TSS), tot...

Evaluation of WHO Criteria to Determine Degree of Dehydration in Children with Acute Diarrhea

OpenAIRE

Sari, Suprawita; Supriatmo; Margaretha, S. L.; Nafianti, S.; Hasibuan, B.; Sinuhaji, A. B.

2005-01-01

Objective To evaluate the diagnostic accuracy and agreement between the 1980 and 1990 WHO criteria for determining the degree of dehydration in children with acute diarrhea. Methods This prospective study was conducted in two hospitals from October 2002 to February 2003. Clinical signs of dehydration all patients were recorded. The degree of dehydration based on the 1980 and 1990 WHO criteria was determined and compared with fluid deficit measured by the difference of body weight on admiss...

Performance of Clinical Signs in the Diagnosis of Dehydration in Children with Acute Gastroenteritis

OpenAIRE

Hoxha, Teuta; Xhelili, Luan; Azemi, Mehmedali; Avdiu, Muharrem; Ismaili-Jaha, Vlora; Efendija-Beqa, Urata; Grajcevci-Uka, Violeta

2015-01-01

Background: Acute evaluation and treatment of children presenting with dehydration represent one of the most common situation in the pediatric emergency department. To identify dehydration in infants and children before treatment, a number of symptoms and clinical signs have been evaluated. The aim of the study was to describe the performance of clinical signs in detecting dehydration in children. Methods: Two hundred children aged 1 month to 5 year were involved in our prospective study. The...

Rhodium catalyzed regioselective arene homologation of aryl urea via double C-H bond activation and migratory insertion of alkyne

Institute of Scientific and Technical Information of China (English)

Yan Wang; Hao Zhou; Ke Xu; Mei-Hua Shen; Hua-Dong Xu

2017-01-01

A convenient rhodium catalyzed oxidative arene homologation of aniline derivatives with symmetrical or unsymmetrical alkynes using Cu(OAc)2 as oxidant is described.Urea group is shown to be effective as a directing group for initial ortho C-H activation.Two migratory insertion events of alkyne into Rh-C bond occur successively,both with complete regioselectivity.This method is particularly useful for synthesis of polyarenes with different substituents,which has not been reported with conventional protocol.A mechanism has been proposed to explain the observed data.

Biphasic single-reactor process for dehydration of xylose and hydrogenation of produced furfural

NARCIS (Netherlands)

Ordomskiy, V.; Schouten, J.C.; Schaaf, van der J.; Nijhuis, T.A.

2013-01-01

The processes of xylose dehydration and the consecutive furfural hydrogenation have been combined in a single biphasic reactor. The dehydration was studied over Amberlyst-15 and the hydrogenation over a hydrophobic Ru/C catalyst. 1-Butanol, 2-methyltetrahydrofuran and cyclohexane were used as

Isothermal dehydration of thin films of water and sugar solutions

Energy Technology Data Exchange (ETDEWEB)

Heyd, R. [Centre de Recherche sur la Matière Divisée, University of Orleans and CNRS, rue de la Férollerie 1B, 45071 Orléans Cedex 2 (France); Rampino, A. [Centre de Recherche sur la Matière Divisée, University of Orleans and CNRS, rue de la Férollerie 1B, 45071 Orléans Cedex 2 (France); Laboratory of Physical and Macromolecular Chemistry, University of Trieste, Via Giorgieri 1, 34127 Trieste (Italy); Bellich, B.; Elisei, E. [Laboratory of Physical and Macromolecular Chemistry, University of Trieste, Via Giorgieri 1, 34127 Trieste (Italy); Cesàro, A. [Laboratory of Physical and Macromolecular Chemistry, University of Trieste, Via Giorgieri 1, 34127 Trieste (Italy); Elettra Sincrotrone Trieste, Area Science Park, I-34149 Trieste (Italy); Saboungi, M.-L. [Centre de Recherche sur la Matière Divisée, University of Orleans and CNRS, rue de la Férollerie 1B, 45071 Orléans Cedex 2 (France); Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie (IMPMC), Sorbonne Univ-UPMC, Univ Paris 06, UMR CNRS 7590, Museum National d’Histoire Naturelle, IRD UMR 206, 4 Place Jussieu, F-75005 Paris (France)

2014-03-28

The process of quasi-isothermal dehydration of thin films of pure water and aqueous sugar solutions is investigated with a dual experimental and theoretical approach. A nanoporous paper disk with a homogeneous internal structure was used as a substrate. This experimental set-up makes it possible to gather thermodynamic data under well-defined conditions, develop a numerical model, and extract needed information about the dehydration process, in particular the water activity. It is found that the temperature evolution of the pure water film is not strictly isothermal during the drying process, possibly due to the influence of water diffusion through the cellulose web of the substrate. The role of sugar is clearly detectable and its influence on the dehydration process can be identified. At the end of the drying process, trehalose molecules slow down the diffusion of water molecules through the substrate in a more pronounced way than do the glucose molecules.

Dehydrating process experiment on spent ion-exchange resin sludge by Funda Filter

International Nuclear Information System (INIS)

Hasegawa, Tatsuo; Ishino, Kazuyuki

1977-01-01

In nuclear power plants, Funda Filters are employed to dehydrate spent powdery ion-exchange resin sludge. The Funda Filter is very effective for eliminating small rust components contained in spent powdery resin slurry; however, in the drying process, the complete drying of spent powdery resin is very difficult because the filter cake of resin on the horizontal filter leaf is likely to crack and let out steam and hot air through the cracks. This paper deals with the results of experiments conducted to clarify the detailed phenomena of dehydration so the above problem could be solved. The above experiments were made on the precoating and drying of granular ion-exchange resin slurry that had not yet been put to practical use. The experiments were composed of one fundamental and one operational stage. In the fundamental experiment, the dehydration properties and dehydration mechanism of resins were made clear, and the most effective operational method was established through the operational experiments conducted using large-scale Funda Filter test equipment under various conditions. (auth.)

Lesion dehydration rate changes with the surface layer thickness during enamel remineralization

Science.gov (United States)

Chang, Nai-Yuan N.; Jew, Jamison M.; Fried, Daniel

2018-02-01

A transparent highly mineralized outer surface zone is formed on caries lesions during remineralization that reduces the permeability to water and plaque generated acids. However, it has not been established how thick the surface zone should be to inhibit the penetration of these fluids. Near-IR (NIR) reflectance coupled with dehydration can be used to measure changes in the fluid permeability of lesions in enamel and dentin. Based on our previous studies, we postulate that there is a strong correlation between the surface layer thickness and the rate of dehydration. In this study, the rates of dehydration for simulated lesions in enamel with varying remineralization durations were measured. Reflectance imaging at NIR wavelengths from 1400-2300 nm, which coincides with higher water absorption and manifests the greatest sensitivity to contrast changes during dehydration measurements, was used to image simulated enamel lesions. The results suggest that the relationship between surface zone thickness and lesion permeability is highly non-linear, and that a small increase in the surface layer thickness may lead to a significant decrease in permeability.

chronic dehydration affects hydroelectrolytic equilibrium and adrenal

African Journals Online (AJOL)

A. Dekar-Madoui

2017-05-01

May 1, 2017 ... response but rather an index of metabolic strategy probably for metabolic ... [11] Dai WJ, Yao T. Effects of dehydration and salt-loading on ... [12] Kondo N, Arima H, Banno R, Kuwahara S, Sato I, Oiso Y. Osmoregulation of.

Accuracy of Inferior Vena Cava Ultrasound for Predicting Dehydration in Children with Acute Diarrhea in Resource-Limited Settings.

Science.gov (United States)

Modi, Payal; Glavis-Bloom, Justin; Nasrin, Sabiha; Guy, Allysia; Chowa, Erika P; Dvor, Nathan; Dworkis, Daniel A; Oh, Michael; Silvestri, David M; Strasberg, Stephen; Rege, Soham; Noble, Vicki E; Alam, Nur H; Levine, Adam C

2016-01-01

Although dehydration from diarrhea is a leading cause of morbidity and mortality in children under five, existing methods of assessing dehydration status in children have limited accuracy. To assess the accuracy of point-of-care ultrasound measurement of the aorta-to-IVC ratio as a predictor of dehydration in children. A prospective cohort study of children under five years with acute diarrhea was conducted in the rehydration unit of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b). Ultrasound measurements of aorta-to-IVC ratio and dehydrated weight were obtained on patient arrival. Percent weight change was monitored during rehydration to classify children as having "some dehydration" with weight change 3-9% or "severe dehydration" with weight change > 9%. Logistic regression analysis and Receiver-Operator Characteristic (ROC) curves were used to evaluate the accuracy of aorta-to-IVC ratio as a predictor of dehydration severity. 850 children were enrolled, of which 771 were included in the final analysis. Aorta to IVC ratio was a significant predictor of the percent dehydration in children with acute diarrhea, with each 1-point increase in the aorta to IVC ratio predicting a 1.1% increase in the percent dehydration of the child. However, the area under the ROC curve (0.60), sensitivity (67%), and specificity (49%), for predicting severe dehydration were all poor. Point-of-care ultrasound of the aorta-to-IVC ratio was statistically associated with volume status, but was not accurate enough to be used as an independent screening tool for dehydration in children under five years presenting with acute diarrhea in a resource-limited setting.

Accuracy of Inferior Vena Cava Ultrasound for Predicting Dehydration in Children with Acute Diarrhea in Resource-Limited Settings.

Directory of Open Access Journals (Sweden)

Payal Modi

Full Text Available Although dehydration from diarrhea is a leading cause of morbidity and mortality in children under five, existing methods of assessing dehydration status in children have limited accuracy.To assess the accuracy of point-of-care ultrasound measurement of the aorta-to-IVC ratio as a predictor of dehydration in children.A prospective cohort study of children under five years with acute diarrhea was conducted in the rehydration unit of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b. Ultrasound measurements of aorta-to-IVC ratio and dehydrated weight were obtained on patient arrival. Percent weight change was monitored during rehydration to classify children as having "some dehydration" with weight change 3-9% or "severe dehydration" with weight change > 9%. Logistic regression analysis and Receiver-Operator Characteristic (ROC curves were used to evaluate the accuracy of aorta-to-IVC ratio as a predictor of dehydration severity.850 children were enrolled, of which 771 were included in the final analysis. Aorta to IVC ratio was a significant predictor of the percent dehydration in children with acute diarrhea, with each 1-point increase in the aorta to IVC ratio predicting a 1.1% increase in the percent dehydration of the child. However, the area under the ROC curve (0.60, sensitivity (67%, and specificity (49%, for predicting severe dehydration were all poor.Point-of-care ultrasound of the aorta-to-IVC ratio was statistically associated with volume status, but was not accurate enough to be used as an independent screening tool for dehydration in children under five years presenting with acute diarrhea in a resource-limited setting.

The diagnostic accuracy of multi-frequency bioelectrical impedance analysis in diagnosing dehydration after stroke

Science.gov (United States)

Kafri, Mohannad W.; Myint, Phyo Kyaw; Doherty, Danielle; Wilson, Alexander Hugh; Potter, John F.; Hooper, Lee

2013-01-01

Background Non-invasive methods for detecting water-loss dehydration following acute stroke would be clinically useful. We evaluated the diagnostic accuracy of multi-frequency bioelectrical impedance analysis (MF-BIA) against reference standards serum osmolality and osmolarity. Material/Methods Patients admitted to an acute stroke unit were recruited. Blood samples for electrolytes and osmolality were taken within 20 minutes of MF-BIA. Total body water (TBW%), intracellular (ICW%) and extracellular water (ECW%), as percentages of total body weight, were calculated by MF-BIA equipment and from impedance measures using published equations for older people. These were compared to hydration status (based on serum osmolality and calculated osmolarity). The most promising Receiver Operating Characteristics curves were plotted. Results 27 stroke patients were recruited (mean age 71.3, SD10.7). Only a TBW% cut-off at 46% was consistent with current dehydration (serum osmolality >300 mOsm/kg) and TBW% at 47% impending dehydration (calculated osmolarity ≥295–300 mOsm/L) with sensitivity and specificity both >60%. Even here diagnostic accuracy of MF-BIA was poor, a third of those with dehydration were wrongly classified as hydrated and a third classified as dehydrated were well hydrated. Secondary analyses assessing diagnostic accuracy of TBW% for men and women separately, and using TBW as a percentage of lean body mass showed some promise, but did not provide diagnostically accurate measures across the population. Conclusions MF-BIA appears ineffective at diagnosing water-loss dehydration after stroke and cannot be recommended as a test for dehydration, but separating assessment by sex, and using TBW as a percentage of lean body weight may warrant further investigation. PMID:23839255

High Prevalence of Dehydration and Inadequate Nutritional Knowledge Among University and Club Level Athletes.

Science.gov (United States)

Magee, Pamela Jane; Gallagher, Alison M; McCormack, Jacqueline M

2017-04-01

Although dehydration of ≥ 2% body weight (BW) loss significantly impairs endurance performance, dehydration remains prevalent among athletes and may be owing to a lack of knowledge in relation to fluid requirements. The aim of this study was to assess the hydration status of university/club level athletes (n = 430) from a range of sports/activities (army officer cadet training; bootcamp training; cycling; Gaelic Athletic Association camogie, football and hurling; golf; hockey; netball; rugby; running (sprinting and endurance); Shotokan karate and soccer) immediately before and after training/competition and to assess their nutritional knowledge. Urine specific gravity (USG) was measured immediately before and after exercise and BW loss during exercise was assessed. Nutritional knowledge was assessed using a validated questionnaire. 31.9% of athletes commenced exercise in a dehydrated state (USG >1.020) with 43.6% of participants dehydrated posttraining/competition. Dehydration was particularly prevalent (>40% of cohort) among karateka, female netball players, army officer cadets, and golfers. Golfers that commenced a competitive 18 hole round dehydrated took a significantly higher number of strokes to complete the round in comparison with their euhydrated counterparts (79.5 ± 2.1 vs. 75.7 ± 3.9 strokes, p = .049). Nutritional knowledge was poor among participants (median total score [IQR]; 52.9% [46.0, 59.8]), albeit athletes who were euhydrated at the start of exercise had a higher overall score in comparison with dehydrated athletes (55.2% vs. 50.6%, p = .001). Findings from the current study, therefore, have significant implications for the education of athletes in relation to their individual fluid requirements around exercise.

Molecular dynamics investigations of regioselectivity of anionic/aromatic substrates by a family of enzymes: a case study of diclofenac binding in CYP2C isoforms.

Science.gov (United States)

Cui, Ying-Lu; Xu, Fang; Wu, Rongling

2016-06-29

The CYP2C subfamily is of particular importance in the metabolism of drugs, food toxins, and procarcinogens. Like other P450 subfamilies, 2C enzymes share a high sequence identity, but significantly contribute in different ways to hepatic capacity to metabolize drugs. They often metabolize the same substrate to more than one product with different catalytic sites. Because it is challenging to characterize experimentally, much still remains unknown about the reason for why the substrate regioselectivity of these closely related subfamily members is different. Here, we have investigated the structural features of CYP2C8, CYP2C9, and CYP2C19 bound with their shared substrate diclofenac to elucidate the underlying molecular mechanism for the substrate regioselectivity of CYP2C subfamily enzymes. The obtained results demonstrate how a sequence divergence for the active site residues causes heterogeneous variations in the secondary structures and in major tunnel selections, and further affects the shape and chemical properties of the substrate-binding site. Structural analysis and free energy calculations showed that the most important determinants of regioselectivity among the CYP2C isoforms are the geometrical features of the active sites, as well as the hydrogen bonds and the hydrophobic interactions, mainly presenting as the various locations of Arg108 and substitutions of Phe205 for Ile205 in CYP2C8. The MM-GB/SA calculations combined with PMF results accord well with the experimental KM values, bridging the gap between the theory and the experimentally observed results of binding affinity differences. The present study provides important insights into the structure-function relationships of CYP2C subfamily enzymes, the knowledge of ligand binding characteristics and key residue contributions could guide future experimental and computational work on the synthesis of drugs with better pharmacokinetic properties so that CYP interactions could be avoided.

DEHYDRATION IN CHILDREN WITH ACUTE DIARRHEA

Directory of Open Access Journals (Sweden)

S. V. Khaliullina

2014-01-01

Full Text Available The article is focused on the main issues of the regulation of water-electrolyte metabolism in children, possible variants of its disorder in acute diarrhoeal diseases. The clinical features of dehydration depending on the severity and qualitative component of losses are described, recommendations on laboratory diagnosis and treatment are provided. 

Pig skin apposite dehydrated by lyophilization

International Nuclear Information System (INIS)

Reyes F, M.L.; Gonzalez V, C.; Flores A, M.; Peralta R, J.; Reboyo B, D.; Rodriguez U, M.D.

2007-01-01

Taking like base a work carried out in 2001 in the Radio sterilized Tissue Bank (BTR) in which lyophilized apposite of pig skin were obtained at laboratory scale, this work is presented that had as purpose to process pig skin to produce temporary covers of skin (apposite) dehydrated by lyophilization to commercial scale. (Author)

Convergent Synthesis of Piperidines by the Union of Conjugated Alkynes with Imines: A Unique Regioselective Bond Construction for Heterocycle Synthesis

Science.gov (United States)

Chen, Ming Z.; Micalizio, Glenn C.

2009-01-01

A two-step process is described for the union of aromatic imines, conjugated alkynes and aldehydes that results in a stereoselective synthesis of highly substituted piperidines. This synthetic process has been made possible by defining a unique regioselective functionalization of conjugated alkynes that establishes a suitably functionalized substrate for subsequent heterocycle-forming cationic annulation. Given the flexibility of the coupling process, heterocycles can be accessed through a process that establishes up to four stereogenic centers and four fused rings. PMID:19817447

Reducing the negative vocal effects of superficial laryngeal dehydration with humidification.

Science.gov (United States)

Levendoski, Elizabeth Erickson; Sundarrajan, Anusha; Sivasankar, M Preeti

2014-07-01

Environmental humidification is a simple, cost-effective method believed to reduce superficial laryngeal drying. This study sought to validate this belief by investigating whether humidification treatment would reduce the negative effects of superficial laryngeal dehydration on phonation threshold pressure (PTP). Phonation threshold pressure data analysis may be vulnerable to bias because of lack of investigator blinding. Consequently, this study investigated the extent of PTP analysis reliability between unblinded and blinded investigators. Healthy male and female adults were assigned to a vocal fatigue (n = 20) or control group (n = 20) based on their responses to a questionnaire. PTP was assessed after 2 hours of mouth breathing in low humidity (dehydration challenge), following a 5-minute break in ambient humidity, and after 2 hours of mouth breathing in high humidity (humidification). PTP significantly increased following the laryngeal dehydration challenge. After humidification, PTP returned toward baseline. These effects were observed in both subject groups. PTP measurements were highly correlated between the unblinded and blinded investigator. Humidification may be an effective approach to decrease the detrimental voice effects of superficial laryngeal dehydration. These data lay the foundation for future investigations aimed at preventing and treating the negative voice changes associated with chronic, surface laryngeal drying.

EPR study on gamma-irradiated fruits dehydrated via osmosis

Energy Technology Data Exchange (ETDEWEB)

Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)]. E-mail: ndyepr@bas.bg; Aleksieva, K. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

2007-06-15

The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and {gamma}-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas {gamma}-irradiated exhibit 'sugar-like' EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples.

The lateral neostriatum is necessary for compensatory ingestive behaviour after intravascular dehydration in female rats.

Science.gov (United States)

Lelos, M J; Harrison, D J; Rosser, A E; Dunnett, S B

2013-12-01

Aberrant striatal function results in an array of physiological symptoms, including impaired consummatory and regulatory behaviours, which can lead to weight loss and dehydration. It was hypothesised, therefore, that cell loss in the neostriatum may contribute to altered fluid intake by regulating physiological signals related to dehydration status. To test this theory, rats with lesions of the lateral neostriatum and sham controls underwent a series of physiological challenges, including the experimental induction of intracellular and intravascular dehydration. No baseline differences in prandial or non-prandial drinking were observed, nor were differences in locomotor activity evident between groups. Furthermore, intracellular dehydration increased water intake in lesion rats in a manner comparable to sham rats. Interestingly, a specific impairment was evident in lesion rats after subcutaneous injection of poly-ethylene glycol was used to induce intravascular dehydration, such that lesion rats failed to adapt their water intake to this physiological change. The results suggest that the striatal lesions resulted in regulatory dysfunction by impairing motivational control over compensatory ingestive behaviour after intravascular hydration, while the physiological signals related to dehydration remain intact. Loss of these cells in neurodegenerative disorders, such Huntington's disease, may contribute to regulatory changes evident in the course of the disease. Copyright © 2013 Elsevier Ltd. All rights reserved.

Thermal dehydration kinetics of phosphogypsum

OpenAIRE

López Gómez, Félix Antonio; Tayibi, Hanan; García-Díaz, Irene; Alguacil, Francisco José

2015-01-01

Phsophogypsum is a by-product from the processing phosphate rock. Before the use of it in cement industry such as setting regulator is necessary a study of dehydration reaction of phosphogypsum to avoid the false setting during the milling. The aim is to study the thermal behavior of two different phosphogypsum sources (Spain and Tunisia) under non-isothermal conditions in argon atmosphere by using Thermo-Gravimetriy, Differential Thermal Analysis (TG-DTA) and Differential Scanning Calori...

Clinical and laboratory assessment of dehydration severity in children with acute gastroenteritis.

Science.gov (United States)

Parkin, Patricia C; Macarthur, Colin; Khambalia, Amina; Goldman, Ran D; Friedman, Jeremy N

2010-03-01

To evaluate clinical and laboratory assessment of dehydration severity in children, 1 to 36 months, with acute gastroenteritis. Clinical and laboratory measures and weight change following rehydration were collected for enrolled children. Pediatric emergency department. Likelihood ratio (LR+) and 95% confidence interval (CI): for a clinical score of 0, the LR+ was 2.2 (95% CI = 0.9-5.3); for a clinical score of 1 to 4, the LR+ was 1.3 (95% CI = 0.90-1.74); for a clinical score of 5 to 8, the LR+ was 5.2 (95% CI = 2.2-12.8); for a venous pH Dehydration Scale and laboratory measures into clinical decision-making algorithms to assess dehydration severity in children with acute gastroenteritis.

The Inverse Demand Oxa-Diels-Alder Reaction of Resorcinarenes: An Experimental and Theoretical Analysis of Regioselectivity and Diastereoselectivity.

Science.gov (United States)

Stefańska, Karolina; Jędrzejewska, Hanna; Wierzbicki, Michał; Szumna, Agnieszka; Iwanek, Waldemar

2016-07-15

The Diels-Alder reaction enables introduction of new functionalities onto the resorcinarene skeleton with simultaneous generation of new stereogenic centers and expansion of the internal cavity. We present highly regio- and diastereoselective inverse electron demand oxa-Diels-Alder reactions of resorcinarene ortho-quinone methide with benzofuran and indene, each generating 12 new stereogenic centers. The mechanism and reasons for regioselectivity and diastereoselectivity were analyzed using theoretical calculations (NBO charges, Fukui functions, transition state energies, and thermodynamic stability of the products). Enantiomers were separated, and their configurations were determined by comparison of experimental and theoretical electronic circular dichroism spectra.

PEGylation of SPIONs by polycondensation reactions: a new strategy to improve colloidal stability in biological media

International Nuclear Information System (INIS)

Viali, Wesley Renato; Silva Nunes, Eloiza da; Santos, Caio Carvalho dos; Silva, Sebastião William da; Aragón, Fermin Herrera; Coaquira, José Antonio Huamaní; Morais, Paulo César; Jafelicci, Miguel

2013-01-01

In this study, we report on a new route of PEGylation of superparamagnetic iron oxide nanoparticles (SPIONs) by polycondensation reaction with carboxylate groups. Structural and magnetic characterizations were performed by X-ray diffractometry (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and vibrating sample magnetometry (VSM). The XRD confirmed the spinel structure with a crystallite average diameter in the range of 3.5–4.1 nm in good agreement with the average diameter obtained by TEM (4.60–4.97 nm). The TGA data indicate the presence of PEG attached onto the SPIONs’ surface. The SPIONs were superparamagnetic at room temperature with saturation magnetization (M S ) from 36.7 to 54.1 emu/g. The colloidal stability of citrate- and PEG-coated SPIONs was evaluated by means of dynamic light scattering measurements as a function of pH, ionic strength, and nature of dispersion media (phosphate buffer and cell culture media). Our findings demonstrated that the PEG polymer chain length plays a key role in the coagulation behavior of the Mag-PEG suspensions. The excellent colloidal stability under the extreme conditions we evaluated, such as high ionic strength, pH near the isoelectric point, and cell culture media, revealed that suspensions comprising PEG-coated SPION, with PEG of molecular weight 600 and above, present steric stabilization attributed to the polymer chains attached onto the surface of SPIONs

PEGylation of SPIONs by polycondensation reactions: a new strategy to improve colloidal stability in biological media

Energy Technology Data Exchange (ETDEWEB)

Viali, Wesley Renato; Silva Nunes, Eloiza da; Santos, Caio Carvalho dos [Universidade Estadual Paulista, Laboratorio de Materiais Magneticos e Coloides, Departamento de Fisico-quimica, Instituto de Quimica (Brazil); Silva, Sebastiao William da; Aragon, Fermin Herrera; Coaquira, Jose Antonio Huamani; Morais, Paulo Cesar [Universidade de Brasilia, Instituto de Fisica, Nucleo de Fisica Aplicada (Brazil); Jafelicci, Miguel, E-mail: jafeli@iq.unesp.br [Universidade Estadual Paulista, Laboratorio de Materiais Magneticos e Coloides, Departamento de Fisico-quimica, Instituto de Quimica (Brazil)

2013-08-15

In this study, we report on a new route of PEGylation of superparamagnetic iron oxide nanoparticles (SPIONs) by polycondensation reaction with carboxylate groups. Structural and magnetic characterizations were performed by X-ray diffractometry (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and vibrating sample magnetometry (VSM). The XRD confirmed the spinel structure with a crystallite average diameter in the range of 3.5-4.1 nm in good agreement with the average diameter obtained by TEM (4.60-4.97 nm). The TGA data indicate the presence of PEG attached onto the SPIONs' surface. The SPIONs were superparamagnetic at room temperature with saturation magnetization (M{sub S}) from 36.7 to 54.1 emu/g. The colloidal stability of citrate- and PEG-coated SPIONs was evaluated by means of dynamic light scattering measurements as a function of pH, ionic strength, and nature of dispersion media (phosphate buffer and cell culture media). Our findings demonstrated that the PEG polymer chain length plays a key role in the coagulation behavior of the Mag-PEG suspensions. The excellent colloidal stability under the extreme conditions we evaluated, such as high ionic strength, pH near the isoelectric point, and cell culture media, revealed that suspensions comprising PEG-coated SPION, with PEG of molecular weight 600 and above, present steric stabilization attributed to the polymer chains attached onto the surface of SPIONs.

Use of osmotic dehydration to improve fruits and vegetables quality during processing.

Science.gov (United States)

Maftoonazad, Neda

2010-11-01

Osmotic treatment describes a preparation step to further processing of foods involving simultaneous transient moisture loss and solids gain when immersing in osmotic solutions, resulting in partial drying and improving the overall quality of food products. The different aspects of the osmotic dehydration (OD) technology namely the solutes employed, solutions characteristics used, process variables influence, as well as, the quality characteristics of the osmodehydrated products will be discussed in this review. As the process is carried out at mild temperatures and the moisture is removed by a liquid diffusion process, phase change that would be present in the other drying processes will be avoided, resulting in high quality products and may also lead to substantial energy savings. To optimize this process, modeling of the mass transfer phenomenon can improve high product quality. Several techniques such as microwave heating, vacuum, high pressure, pulsed electric field, etc. may be employed during or after osmotic treatment to enhance performance of the osmotic dehydration. Moreover new technologies used in osmotic dehydration will be discussed. Patents on osmotic dehydration of fruits and vegetables are also discussed in this article.

Nocturnal lagophthalmos: never seen before in hypernatraemic dehydration.

Science.gov (United States)

Rai, Birendra; Moka, Sudha; Sharif, Farhana

2014-04-11

We present two cases in which a 10-month-old male infant and another 15-month-old female child presented with symptoms of sleeping with their eyes wide open (lagophthalmos) with features of gastroenteritis (GE) and dehydration. The first child had been seen and discharged the previous day from the paediatric emergency department (ED) with a diagnosis of GE. He presented the following day with sleeping discomfort with his eyes wide open and ongoing symptoms of GE. The second child presented to the ED with features of GE. She was found to be sleeping in the ED with her eyes wide open. Investigations of both children revealed hypernatraemic dehydration. Correction of the electrolyte imbalance in both cases over a period of 48 h led to the resolution of symptoms.

Pulmonary hypertension and right heart failure due to severe hypernatremic dehydration.

Science.gov (United States)

Chiwane, Saurabh; Ahmed, Tageldin M; Bauerfeld, Christian P; Chauhan, Monika

2017-07-01

Neonates are at risk of developing hypernatremic dehydration and its associated complications, such as stroke, dural sinus thrombosis and renal vein thrombosis. Pulmonary hypertension has not been described as a complication of hypernatremia. We report a case of a seven-day-old neonate with severe hypernatremic dehydration who went on to develop pulmonary hypertension and right heart failure needing extracorporeal membrane oxygenation (ECMO). Normal or high anion gap metabolic acidosis commonly accompanies hypernatremic dehydration. The presence of acidosis and/or hypoxia can delay the normal drop in pulmonary vascular resistance (PVR) after birth, causing pulmonary hypertension and right ventricular failure. A high index of suspicion is paramount to diagnose pulmonary hypertension and aggressive correction of the acidosis and hypoxia is needed. In the presence of severe right ventricular failure, ECMO can be used as a bridge to recovery while underlying metabolic derangements are being corrected.

Memory responses of jasmonic acid-associated Arabidopsis genes to a repeated dehydration stress.

Science.gov (United States)

Liu, Ning; Staswick, Paul E; Avramova, Zoya

2016-11-01

Dehydration stress activates numerous genes co-regulated by diverse signaling pathways. Upon repeated exposures, however, a subset of these genes does not respond maintaining instead transcription at their initial pre-stressed levels ('revised-response' genes). Most of these genes are involved in jasmonic acid (JA) biosynthesis, JA-signaling and JA-mediated stress responses. How these JA-associated genes are regulated to provide different responses to similar dehydration stresses is an enigma. Here, we investigate molecular mechanisms that contribute to this transcriptional behavior. The memory-mechanism is stress-specific: one exposure to dehydration stress or to abscisic acid (ABA) is required to prevent transcription in the second. Both ABA-mediated and JA-mediated pathways are critical for the activation of these genes, but the two signaling pathways interact differently during a single or multiple encounters with dehydration stress. Synthesis of JA during the first (S1) but not the second dehydration stress (S2) accounts for the altered transcriptional responses. We propose a model for these memory responses, wherein lack of MYC2 and of JA synthesis in S2 is responsible for the lack of expression of downstream genes. The similar length of the memory displayed by different memory-type genes suggests biological relevance for transcriptional memory as a gene-regulating mechanism during recurring bouts of drought. © 2016 John Wiley & Sons Ltd.

Heat stress and dehydration in adapting for performance: Good, bad, both, or neither?

Science.gov (United States)

Akerman, Ashley Paul; Tipton, Michael; Minson, Christopher T; Cotter, James David

2016-01-01

Physiological systems respond acutely to stress to minimize homeostatic disturbance, and typically adapt to chronic stress to enhance tolerance to that or a related stressor. It is legitimate to ask whether dehydration is a valuable stressor in stimulating adaptation per se . While hypoxia has had long-standing interest by athletes and researchers as an ergogenic aid, heat and nutritional stressors have had little interest until the past decade. Heat and dehydration are highly interlinked in their causation and the physiological strain they induce, so their individual roles in adaptation are difficult to delineate. The effectiveness of heat acclimation as an ergogenic aid remains unclear for team sport and endurance athletes despite several recent studies on this topic. Very few studies have examined the potential ergogenic (or ergolytic) adaptations to ecologically-valid dehydration as a stressor in its own right, despite longstanding evidence of relevant fluid-regulatory adaptations from short-term hypohydration. Transient and self-limiting dehydration (e.g., as constrained by thirst), as with most forms of stress, might have a time and a place in physiological or behavioral adaptations independently or by exacerbating other stressors (esp. heat); it cannot be dismissed without the appropriate evidence. The present review did not identify such evidence. Future research should identify how the magnitude and timing of dehydration might augment or interfere with the adaptive processes in behaviorally constrained versus unconstrained humans.

The Influence of the Osmotic Dehydration Process on Physicochemical Properties of Osmotic Solution.

Science.gov (United States)

Lech, Krzysztof; Michalska, Anna; Wojdyło, Aneta; Nowicka, Paulina; Figiel, Adam

2017-12-16

The osmotic dehydration (OD) process consists of the removal of water from a material during which the solids from the osmotic solution are transported to the material by osmosis. This process is commonly performed in sucrose and salt solutions. Taking into account that a relatively high consumption of those substances might have a negative effect on human health, attempts have been made to search for alternatives that can be used for osmotic dehydration. One of these is an application of chokeberry juice with proven beneficial properties to human health. This study aimed to evaluate the physicochemical properties of the OD solution (chokeberry juice concentrate) before and after the osmotic dehydration of carrot and zucchini. The total polyphenolics content, antioxidant capacity (ABTS, FRAP), dynamic viscosity, density, and water activity were examined in relation to the juice concentration used for the osmotic solution before and after the OD process. During the osmotic dehydration process, the concentration of the chokeberry juice decreased. Compounds with lower molecular weight and lower antioxidant capacity present in concentrated chokeberry juice had a stronger influence on the exchange of compounds during the OD process in carrot and zucchini. The water activity of the osmotic solution increased after the osmotic dehydration process. It was concluded that the osmotic solution after the OD process might be successfully re-used as a product with high quality for i.e. juice production.

Development and characterisation of hybrid polysaccharide membranes for dehydration processes.

Science.gov (United States)

Meireles, Inês T; Huertas, Rosa M; Torres, Cristiana A V; Coelhoso, Isabel M; Crespo, João G

2018-07-01

The purpose of this work is the development and characterisation of new hybrid polysaccharide (FucoPol) membranes. These membranes were prepared by incorporation of a SiO 2 network homogeneously dispersed by using a sol-gel method with GPTMS as a crosslinker silica precursor. They were further crosslinked with CaCl 2 for reinforcement of mechanical properties and improvement of their permeation performance. They were characterised in terms of their structural, mechanical and thermal properties. They presented a dense and homogeneous structure, resistant to deformation, with a Tg of 43 °C and a thermal decomposition between 240 and 251 °C. The hybrid FucoPol membranes were tested for ethanol dehydration by pervaporation and also for nitrogen dehydration. They exhibited high water selectivity values, similar to PERVAP ® 4101, however they lost their stability when exposed to solutions of 10.0 wt.% water in ethanol. In contrast, these membranes were stable when applied in N 2 dehydration, leading to reproducible performance and very high water selectivities. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dehydration Behaviour of Borax Pentahydrate to Anhydrous Borax by Multi-Stage Heating in a Fluidized

OpenAIRE

ŞAHİN, Ömer

2002-01-01

In order to optimize the anhydrous borax process in a fluidized bed calcinator, it is absolutely necessary to study the dehydration behaviour of borax pentahydrate. It was found that the basic feature of the dehydration of borax pentahydrate to anhydrous borax is concerned with the conditions employed. The bulk density and sodium borate content of the end product were determined to be a function of number of stages of temperature of the dehydration period in the fluidized bed. It...

Permeability of gypsum samples dehydrated in air

Science.gov (United States)

Milsch, Harald; Priegnitz, Mike; Blöcher, Guido

2011-09-01

We report on changes in rock permeability induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air (dry) for up to 800 h at ambient pressure and temperatures between 378 and 423 K. Subsequently, the reaction kinetics, so induced changes in porosity, and the concurrent evolution of sample permeability were constrained. Weighing the heated samples in predefined time intervals yielded the reaction progress where the stoichiometric mass balance indicated an ultimate and complete dehydration to anhydrite regardless of temperature. Porosity showed to continuously increase with reaction progress from approximately 2% to 30%, whilst the initial bulk volume remained unchanged. Within these limits permeability significantly increased with porosity by almost three orders of magnitude from approximately 7 × 10-19 m2 to 3 × 10-16 m2. We show that - when mechanical and hydraulic feedbacks can be excluded - permeability, reaction progress, and porosity are related unequivocally.

Dehydration of alcohols over oxide catalysts: γ-eliminations -- stereospecificity and selectivity

International Nuclear Information System (INIS)

Siddhan, S.; Narayanan, K.

1979-01-01

The effect of alkali impregnation on alumina catalysts has been investigated by a physicochemical study of pure and modified alumina catalyst samples. The stereospecificity and selectivity of dehyration reactions, as well as the incidence of γ-elimination, have been studied by passing suitable substrates over catalyst samples. There was a change in the acidity-basicity balance in the sodium-impregnated alumina samples vis a vis pure alumina, while the surface area virtually remained constant. A higher propensity for γ-elimination was noticed with increases in basicity of the catalyst. 1-Olefin formation was found to be larger in more basic alumina- and thoria-catalyzed dehydration reactions. Thoria was strikingly unique in its capacity to dehydrate only alcohols, which have at least one β-hydrogen atom. Neopentyl alcohol could not be dehydrated even under drastic conditions. The modes of elimination in the case of alumina and thoria have been shown to be anti and syn, respectively, from the results of the dehydration studies with threo-3-methyl-2-pentanol. Studies of alcohols with proper β-substituents revealed that the cis preference is not universal in all catalytic eliminations but, in fact, depends on the mode of elimination. While cis-preference was noticed in alumina-catalyzed anti eliminations, trans-olefin was formed to a major amount in thoria-catalyzed syn-elimination processes. 9 figures, 13 tables

DEHYDRATION IN SOCCER PLAYERS AFTER A MATCH IN THE HEAT

Directory of Open Access Journals (Sweden)

J.C.B. Marins

2011-11-01

Full Text Available We investigated the level of dehydration after a match in 20 soccer players (mean ± SD, 17.9 ± 1.3 years old, height 1.75 ± 0.05 m, body mass 70.71± 7.65 kg from two teams that participate in a Brazilian Championship game performed at a temperature of 29 ± 1.1 C and a relative humidity of 64 ± 4.2%. Body mass, urine specific gravity and urinary protein were measured before and after the match, and self-perception measurements were performed during the match. Body mass loss was 1.00 ± 0.39 kg, corresponding to a dehydration percentage of 1.35 ± 0.87%. The mean sweating rate during the match was 866 ± 319 ml · h[sup]-1[/sup] and total fluid intake was 1265.00 ± 505.45 ml. The sweating rate and the quantity of ingested fluids correlated positively (r = 0.98; P<0.05. Protein occurred in the urine in 18 soccer players. The players showed no perception of thirst and considered themselves as comfortable during the match. At the end of the match the soccer players replaced 57.7 ± 15% of the water loss and presented a condition of significant to severe dehydration based on the post-match urine specific gravity data (1.027 ± 6 g · ml[sup]-1[/sup]. The results of this study demonstrate that most of the soccer players began the match with some degree of dehydration that worsened during the match.

Non-isothermal dehydration kinetic study of aspartame hemihydrate using DSC, TGA and DSC-FTIR microspectroscopy

Directory of Open Access Journals (Sweden)

Wei-hsien Hsieh

2018-05-01

Full Text Available Three thermal analytical techniques such as differential scanning calorimetry (DSC, thermal gravimetric analysis (TGA using five heating rates, and DSC-Fourier Transform Infrared (DSC-FTIR microspectroscopy using one heating rate, were used to determine the thermal characteristics and the dehydration process of aspartame (APM hemihydrate in the solid state. The intramolecular cyclization process of APM anhydrate was also examined. One exothermic and four endothermic peaks were observed in the DSC thermogram of APM hemihydrate, in which the exothermic peak was due to the crystallization of some amorphous APM caused by dehydration process from hemihydrate to anhydride. While four endothermic peaks were corresponded to the evaporation of absorbed water, the dehydration of hemihydrate, the diketopiperazines (DKP formation via intramolecular cyclization, and the melting of DKP, respectively. The weight loss measured in TGA curve of APM hemihydrate was associated with these endothermic peaks in the DSC thermogram. According to the Flynn–Wall–Ozawa (FWO model, the activation energy of dehydration process within 100–150 °C was about 218 ± 11 kJ/mol determined by TGA technique. Both the dehydration and DKP formation processes for solid-state APM hemihydrate were markedly evidenced from the thermal-responsive changes in several specific FTIR bands by a single-step DSC-FTIR microspectroscopy. Keywords: Aspartame (APM hemihydrate, DSC/TGA, DSC-FTIR, Dehydration, Activation energy, DKP formation

Catalytic dehydration of ethanol using transition metal oxide catalysts.

Science.gov (United States)

Zaki, T

2005-04-15

The aim of this work is to study catalytic ethanol dehydration using different prepared catalysts, which include Fe(2)O(3), Mn(2)O(3), and calcined physical mixtures of both ferric and manganese oxides with alumina and/or silica gel. The physicochemical properties of these catalysts were investigated via X-ray powder diffraction (XRD), acidity measurement, and nitrogen adsorption-desorption at -196 degrees C. The catalytic activities of such catalysts were tested through conversion of ethanol at 200-500 degrees C using a catalytic flow system operated under atmospheric pressure. The results obtained indicated that the dehydration reaction on the catalyst relies on surface acidity, whereas the ethylene production selectivity depends on the catalyst chemical constituents.

Regioselectivity in the Thermal Rearrangement of Unsymmetrical 4-Methyl-4H-1,2,4-triazoles to 1-Methyl-1H-1,2,4-triazoles

Directory of Open Access Journals (Sweden)

Per H.J. Carlsen

2001-11-01

Full Text Available The rearrangement of 4-methyl-3,5-diaryl-4H-1,2,4-triazoles to the corresponding 1-methyl-3,5-diaryl-1H-1,2,4-triazoles showed regioselectivity comparable to that observed for the alkylation of 3,5-diaryl-1H-1,2,4-triazoles. This lends support to a proposed mechanism for the rearrangement that involves consecutive nucleophilic displacements steps.

Biochemical degradation and physical migration of polyphenolic compounds in osmotic dehydrated blueberries with pulsed electric field and thermal pretreatments.

Science.gov (United States)

Yu, Yuanshan; Jin, Tony Z; Fan, Xuetong; Wu, Jijun

2018-01-15

Fresh blueberries were pretreated by pulsed electric fields (PEF) or thermal pretreatment and then were subject to osmotic dehydration. The changes in contents of anthocyanins, predominantly phenolic acids and flavonols, total phenolics, polyphenol oxidase (PPO) activity and antioxidant activity in the blueberry samples during pretreatment and osmotic dehydration were investigated. Biochemical degradation and physical migration of these nutritive compounds from fruits to osmotic solutions were observed during the pretreatments and osmotic dehydration. PEF pretreated samples had the least degradation loss but the most migration loss of these compounds compared to thermally pretreated and control samples. Higher rates of water loss and solid gain during osmotic dehydration were also obtained by PEF pretreatment, reducing the dehydration time from 130 to 48h. PEF pretreated and dehydrated fruits showed superior appearance to thermally pretreated and control samples. Therefore, PEF pretreatment is a preferred technology that balances nutritive quality, appearance, and dehydration rate. Published by Elsevier Ltd.

Comparative transcriptome analysis of differentially expressed genes in foxtail millet (Setaria italica L.) during dehydration stress.

Science.gov (United States)

Lata, Charu; Sahu, Pranav Pankaj; Prasad, Manoj

2010-03-19

Dehydration stress is one of the most important abiotic stresses that adversely influence crop growth and productivity. With the aim to understand the molecular mechanisms underlying dehydration stress tolerance in foxtail millet (Setaria italica L.), a drought tolerant crop, we examined its transcriptome changes at two time points (early and late) of dehydration stress. Two suppression subtractive hybridization (SSH) forward libraries were constructed from 21-day old seedlings of tolerant cv. Prasad at 0.5 and 6h PEG-induced dehydration stress. A total of 327 unique ESTs were identified from both libraries and were classified into 11 different categories according to their putative functions. The plant response against dehydration stress was complex, representing major transcripts involved in metabolism, stress, signaling, transcription regulation, translation and proteolysis. By Reverse Northern (RN) technique we identified the differential expression pattern of 327 transcripts, 86 (about 26%) of which showed > or = 1.7-fold induction. Further the obtained results were validated by quantitative real-time PCR (qRT-PCR) to have a comparative expression profiling of randomly chosen 9 up-regulated transcripts (> or =2.5 fold induction) between cv. Prasad (tolerant) and cv. Lepakshi (sensitive) upon dehydration stress. These transcripts showed a differential expression pattern in both cultivars at different time points of stress treatment as analyzed by qRT-PCR. The possible relationship of the identified transcripts with dehydration tolerance mechanism is discussed. Copyright 2010 Elsevier Inc. All rights reserved.

Dehydration Stress Contributes to the Enhancement of Plant Defense Response and Mite Performance on Barley

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M. E. Santamaria

2018-04-01

Full Text Available Under natural conditions, plants suffer different stresses simultaneously or in a sequential way. At present, the combined effect of biotic and abiotic stressors is one of the most important threats to crop production. Understanding how plants deal with the panoply of potential stresses affecting them is crucial to develop biotechnological tools to protect plants. As well as for drought stress, the economic importance of the spider mite on agriculture is expected to increase due to climate change. Barley is a host of the polyphagous spider mite Tetranychus urticae and drought produces important yield losses. To obtain insights on the combined effect of drought and mite stresses on the defensive response of this cereal, we have analyzed the transcriptomic responses of barley plants subjected to dehydration (water-deficit treatment, spider mite attack, or to the combined dehydration-spider mite stress. The expression patterns of mite-induced responsive genes included many jasmonic acid responsive genes and were quickly induced. In contrast, genes related to dehydration tolerance were later up-regulated. Besides, a higher up-regulation of mite-induced defenses was showed by the combined dehydration and mite treatment than by the individual mite stress. On the other hand, the performance of the mite in dehydration stressed and well-watered plants was tested. Despite the stronger defensive response in plants that suffer dehydration and mite stresses, the spider mite demonstrates a better performance under dehydration condition than in well-watered plants. These results highlight the complexity of the regulatory events leading to the response to a combination of stresses and emphasize the difficulties to predict their consequences on crop production.

Dehydration Stress Contributes to the Enhancement of Plant Defense Response and Mite Performance on Barley

Science.gov (United States)

Santamaria, M. E.; Diaz, Isabel; Martinez, Manuel

2018-01-01

Under natural conditions, plants suffer different stresses simultaneously or in a sequential way. At present, the combined effect of biotic and abiotic stressors is one of the most important threats to crop production. Understanding how plants deal with the panoply of potential stresses affecting them is crucial to develop biotechnological tools to protect plants. As well as for drought stress, the economic importance of the spider mite on agriculture is expected to increase due to climate change. Barley is a host of the polyphagous spider mite Tetranychus urticae and drought produces important yield losses. To obtain insights on the combined effect of drought and mite stresses on the defensive response of this cereal, we have analyzed the transcriptomic responses of barley plants subjected to dehydration (water-deficit) treatment, spider mite attack, or to the combined dehydration-spider mite stress. The expression patterns of mite-induced responsive genes included many jasmonic acid responsive genes and were quickly induced. In contrast, genes related to dehydration tolerance were later up-regulated. Besides, a higher up-regulation of mite-induced defenses was showed by the combined dehydration and mite treatment than by the individual mite stress. On the other hand, the performance of the mite in dehydration stressed and well-watered plants was tested. Despite the stronger defensive response in plants that suffer dehydration and mite stresses, the spider mite demonstrates a better performance under dehydration condition than in well-watered plants. These results highlight the complexity of the regulatory events leading to the response to a combination of stresses and emphasize the difficulties to predict their consequences on crop production. PMID:29681917

Associations Between Dehydration, Cognitive Impairment, and Frailty in Older Hospitalized Patients: An Exploratory Study.

Science.gov (United States)

McCrow, Judy; Morton, Margaret; Travers, Catherine; Harvey, Keren; Eeles, Eamonn

2016-05-01

HOW TO OBTAIN CONTACT HOURS BY READING THIS ARTICLE INSTRUCTIONS 1.2 contact hours will be awarded by Villanova University College of Nursing upon successful completion of this activity. A contact hour is a unit of measurement that denotes 60 minutes of an organized learning activity. This is a learner-based activity. Villanova University College of Nursing does not require submission of your answers to the quiz. A contact hour certificate will be awarded once you register, pay the registration fee, and complete the evaluation form online at http://goo.gl/gMfXaf. To obtain contact hours you must: 1. Read the article, "Associations Between Dehydration, Cognitive Impairment, and Frailty in Older Hospitalized Patients: An Exploratory Study" found on pages 19-27, carefully noting any tables and other illustrative materials that are included to enhance your knowledge and understanding of the content. Be sure to keep track of the amount of time (number of minutes) you spend reading the article and completing the quiz. 2. Read and answer each question on the quiz. After completing all of the questions, compare your answers to those provided within this issue. If you have incorrect answers, return to the article for further study. 3. Go to the Villanova website listed above to register for contact hour credit. You will be asked to provide your name; contact information; and a VISA, MasterCard, or Discover card number for payment of the $20.00 fee. Once you complete the online evaluation, a certificate will be automatically generated. This activity is valid for continuing education credit until April 30, 2019. CONTACT HOURS This activity is co-provided by Villanova University College of Nursing and SLACK Incorporated. Villanova University College of Nursing is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's Commission on Accreditation. ACTIVITY OBJECTIVES 1. Describe the incidence of dehydration in older hospitalized

NOVEL POLYMERIC MEMBRANE FOR DEHYDRATION OF ORGANIC SOLVENTS

Science.gov (United States)

Pervaporation has emerged as an economically viable alternative technology for dehydration of organic solvents, removal of organic compounds and organic/organic separations. Development of a membrane system with suitable flux and selectivity characteristics plays a critical role...

Hetero-azeotropic distillation: combining fungal dehydration and lipid extraction.

Science.gov (United States)

Tough, A J; Isabella, B L; Beattie, J E; Herbert, R A

2000-01-01

A low-cost single-stage laboratory process combining fungal dehydration and lipid extraction was compared with a traditional two-stage method employing freeze-drying and subsequent mechanical disruption in the presence of solvent. The ability of a number of organic solvents to form hetero-azeotropes with water was exploited. Chloroform, cyclohexane and hexane were assessed in their abilities to both dry and extract lipid from the oleaginous phycomycete Mortierella alpina (ATCC 32222). Drying rate and lipid extraction were maximised under conditions that prevented fungal agglomeration. The total processing time was limited by the rate of dehydration rather than by the rate of lipid extraction. In all cases azeotropic distillation facilitated a greater rate of dehydration than was possible with freeze-drying. A consequent reduction in overall processing time was observed. Uniquely, both the solvent used and the mode of mixing employed controlled the morphology of the aggregates formed during distillation. In combination with mild mixing chloroform discouraged agglomeration whereas cyclohexane and hexane promoted aggregation. Successful lipid extraction was dependent on the use of dry biomass rather than on the application of heat to effect distillation. Neither the application of heat nor the solvent employed had any significant effect on the lipid composition of the extracted oil.

Preventing and treating dehydration in the elderly during periods of illness and warm weather

NARCIS (Netherlands)

Schols, J.M.G.A.; Groot, de C.P.G.M.; Cammen, van der T.J.M.; Olde Rikkert, M.G.M.

2009-01-01

Objective: Translate the available knowledge on ageing and dehydration into main messages for clinical practice. Main points: Older people are more susceptible to dehydration than younger people. This is partly due to lack of thirst sensation and changes in the water and sodium balance that

Preventing and treating dehydration in the elderly during periods of illness and warm weather.

NARCIS (Netherlands)

Schols, J.M.; Groot, C.P.G.M. de; Cammen, T.J.M. van der; Olde Rikkert, M.G.M.

2009-01-01

OBJECTIVE: Translate the available knowledge on ageing and dehydration into main messages for clinical practice. MAIN POINTS: Older people are more susceptible to dehydration than younger people. This is partly due to lack of thirst sensation and changes in the water and sodium balance that

Iron-Catalyzed Dehydration of Aldoximes to Nitriles Requiring Neither Other Reagents Nor Nitrile Media.

Science.gov (United States)

Hyodo, Kengo; Kitagawa, Saki; Yamazaki, Masayuki; Uchida, Kingo

2016-05-06

The dehydration of aldoximes is an environmentally benign reaction affording the desired nitrile and water as a by-product. However, most of the reported catalytic dehydration reactions of aldoximes require a solvent containing nitrile to synthesize the corresponding nitrile compounds. Inspired by recent reports on the enzymatic synthesis under nitrile-free conditions, we here describe that a simple iron salt catalyzes the dehydration of aldoximes requiring neither other reagents nor nitrile media. Our method can be applied to the one-pot synthesis of nitiriles from aldehydes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Heat integrated ethanol dehydration flowsheets

Energy Technology Data Exchange (ETDEWEB)

Hutahaean, L.S.; Shen, W.H.; Brunt, V. Van [Univ. of South Carolina, Columbia, SC (United States)

1995-04-01

zA theoretical evaluation of heat-integrated heterogeneous-azeotropic ethanol-water distillation flowsheets is presented. Simulations of two column flowsheets using several different hydrocarbon entrainers reveal a region of potential heat integration and substantial reduction in operating energy. In this paper, methods for comparing hydrocarbon entrainers are shown. Two aspects of entrainers are related to operating and capital costs. The binary azeotropic composition of the entrainer-ethanol mixture is related to the energy requirements of the flowsheet. A temperature difference in the azeotrophic column is related to the size of the column and overall process staging requirements. Although the hydrophobicity of an entrainer is essential for specification of staging in the dehydration column, no substantial increase in operating energy results from an entrainer that has a higher water content. Likewise, liquid-liquid equilibria between several entrainer-ethanol-water mixtures have no substantial effect on either staging or operation. Rather, increasing the alcohol content of the entrainer-ethanol azeotrope limits its recovery in the dehydration column, and increases the recycle and reflux streams. These effects both contribute to increasing the separation energy requirements and reducing the region of potential heat integration. A cost comparison with a multieffect extractive distillation flowsheet reveals that the costs are comparable; however, the extractive distillation flowsheet is more cost effective as operating costs increase.

Comprehensive Evaluation of dehydration impact on ocular tissue during Ramadan fasting

Directory of Open Access Journals (Sweden)

Javad Heravian

2015-05-01

Full Text Available Purpose: The present study aimed to review the effect of dehydration during Ramadan fasting on the health and ocular parameters leading to changes in eye function. Methods: Articles included in the study were taken from Pub Med, Ovid, Web of Science and Google Scholar up to 2014.Related articles were also obtained from scientific journals in fasting and eye. Results: Dehydration and nutrition changes in Ramadan cause an increase in tear osmolarity, ocular aberration, anterior chamber depth, IOL measurement, central corneal thickness, retinal and choroidal thickness. And also a decrease in IOP, tear secretion, and vitreous thickness. Conclusion: Besides many research in relation to effect of dehydration impact on ocular parameters during Ramadan fasting, although the findings reveal it is associated with significant changes on ocular parameters. It seems requisite to have comprehensive study in "fasting and ocular parameters” which will be helpful in making decision and giving plan to the patients.

Synthesis of chitosan-PEO hydrogels via mesylation and regioselective Cu(I)-catalyzed cycloaddition.

Science.gov (United States)

Tirino, Pasquale; Laurino, Rosaria; Maglio, Giovanni; Malinconico, Mario; d'Ayala, Giovanna Gomez; Laurienzo, Paola

2014-11-04

In this work, a well-defined hydrogel was developed by coupling chitosan with PEO through "click chemistry". Azide functionalities were introduced onto chitosan, through mesylation of C-6 hydroxyl groups, and reacted with a di-alkyne PEO by a regioselective Cu(I)-catalyzed cycloaddition. This synthetic approach allowed us to obtain a hydrogel with a controlled crosslinking degree. In fact, the extent of coupling is strictly dependent on the amount of azido groups on chitosan, which in turn can be easily modulated. The obtained hydrogel, with a crosslinking degree of around 90%, showed interesting swelling properties. With respect to chitosan hydrogels reported in literature, a considerably higher equilibrium uptake was reached (940%). The possibility to control the crosslinking degree of hydrogel and its capability to rapidly absorb high amounts of water make this material suitable for several applications, such as controlled drug release and wound healing. Copyright © 2014. Published by Elsevier Ltd.

Dehydration Influences Mood and Cognition: A Plausible Hypothesis?

Science.gov (United States)

Benton, David

2011-01-01

The hypothesis was considered that a low fluid intake disrupts cognition and mood. Most research has been carried out on young fit adults, who typically have exercised, often in heat. The results of these studies are inconsistent, preventing any conclusion. Even if the findings had been consistent, confounding variables such as fatigue and increased temperature make it unwise to extrapolate these findings. Thus in young adults there is little evidence that under normal living conditions dehydration disrupts cognition, although this may simply reflect a lack of relevant evidence. There remains the possibility that particular populations are at high risk of dehydration. It is known that renal function declines in many older individuals and thirst mechanisms become less effective. Although there are a few reports that more dehydrated older adults perform cognitive tasks less well, the body of information is limited and there have been little attempt to improve functioning by increasing hydration status. Although children are another potentially vulnerable group that have also been subject to little study, they are the group that has produced the only consistent findings in this area. Four intervention studies have found improved performance in children aged 7 to 9 years. In these studies children, eating and drinking as normal, have been tested on occasions when they have and not have consumed a drink. After a drink both memory and attention have been found to be improved. PMID:22254111

Experimental Evaluation of Mechanical Dehydration of Nigerian ...

African Journals Online (AJOL)

However the quality of the products produced at the higher temperatures is somewhat lower than that of 500C. The results indicate a need for further investigation of the fermentation process. dehydration at lower temperatures than 50°C, and the quantitative analysis of the theobromine content of the finished product.

Construction and application of EST library from Setaria italica in response to dehydration stress.

Science.gov (United States)

Zhang, Jinpeng; Liu, Tingsong; Fu, Junjie; Zhu, Yun; Jia, Jinping; Zheng, Jun; Zhao, Yinhe; Zhang, Ying; Wang, Guoying

2007-07-01

Foxtail millet is a gramineous crop with low water requirement. Despite its high water use efficiency, less attention has been paid to the molecular genetics of foxtail millet. This article reports the construction of subtracted cDNA libraries from foxtail millet seedlings under dehydration stress and the expression profile analysis of 1947 UniESTs from the subtracted cDNA libraries by a cDNA microarray. The results showed that 95 and 57 ESTs were upregulated by dehydration stress, respectively, in roots and shoots of seedlings and that 10 and 27 ESTs were downregulated, respectively, in roots and shoots. The expression profile analysis showed that genes induced in foxtail millet roots were different from those in shoots during dehydration stress and that the early response to dehydration stress in foxtail millet roots was the activation of the glycolysis metabolism. Moreover, protein degradation pathway may also play a pivotal role in drought-tolerant responses of foxtail millet. Finally, Northern blot analysis validated well the cDNA microarray data.

Plasma water as a diagnostic tool in the assessment of dehydration in children with acute gastroenteritis.

Science.gov (United States)

Plaisier, Annemarie; Maingay-de Groof, Femke; Mast-Harwig, Roechama; Kalkman, Patricia M J; Wulkan, Remi W; Verwers, Renee; Neele, Marjolein; Hop, Wim C J; Groeneweg, Michael

2010-07-01

Acute gastroenteritis is common in childhood. The estimation of the degree of dehydration is essential for management of acute gastroenteritis. Plasma water was assessed as a diagnostic tool in children with acute gastroenteritis and dehydration admitted to hospital. In a prospective cohort study, 101 patients presenting at the emergency department with dehydration were included. Clinical assessment, routine laboratory tests, and plasma water measurement were performed. Plasma water was measured as a percentage of water content using dry weight method. During admission, patients were rehydrated in 12 h. Weight gain at the end of the rehydration period and 2 weeks thereafter was used to determine the percentage of weight loss as a gold standard for the severity of dehydration. Clinical assessment of dehydration was not significantly associated with the percentage of weight loss. Blood urea nitrogen (r = 0.3, p = 0.03), base excess (r =-0.31, p = 0.03), and serum bicarbonate (r = 0.32, p = 0.02) were significantly correlated with the percentage of weight loss. Plasma water did not correlate with the percentage of weight loss. On the basis of the presented data, plasma water should not be used as a diagnostic tool in the assessment of dehydration in children with acute gastroenteritis.

Dehydration in the tropical tropopause layer estimated from the water vapor match

Directory of Open Access Journals (Sweden)

Y. Inai

2013-09-01

Full Text Available We apply the match technique, whereby the same air mass is observed more than once and such cases are termed a "match", to study the dehydration process associated with horizontal advection in the tropical tropopause layer (TTL over the western Pacific. The matches are obtained from profile data taken by the Soundings of Ozone and Water in the Equatorial Region (SOWER campaign network observations using isentropic trajectories calculated from European Centre for Medium-Range Weather Forecasts (ECMWF operational analyses. For the matches identified, extensive screening procedures are performed to verify the representativeness of the air parcel and the validity of the isentropic treatment, and to check for possible water injection by deep convection, consistency between the sonde data and analysis field referring to the ozone conservation. Among the matches that passed the screening tests, we identified some cases corresponding to the first quantitative value of dehydration associated with horizontal advection in the TTL. The statistical features of dehydration for the air parcels advected in the lower TTL are derived from the matches. The threshold of nucleation is estimated to be 146 ± 1% (1σ in relative humidity with respect to ice (RHice, while dehydration seems to continue until RHice reaches about 75 ± 23% (1σ in the altitude region from 350 to 360 K. The efficiency of dehydration expressed by the relaxation time required for the supersaturated air parcel to approach saturation is empirically determined from the matches. A relaxation time of approximately one hour reproduces the second water vapor observation reasonably well, given the first observed water vapor amount and the history of the saturation mixing ratio during advection in the lower TTL.

Modulating the regioselectivity of a Pasteurella multocida sialyltransferase for biocatalytic production of 3'- and 6'-sialyllactose

DEFF Research Database (Denmark)

Guo, Yao; Jers, Carsten; Meyer, Anne S.

2015-01-01

Several bacterial sialyltransferases have been reported to be multifunctional also catalysing sialidase and trans-sialidase reactions. In this study, we examined the trans-sialylation efficacy and regioselectivity of mutants of the multifunctional Pasteurella multocida sialyltransferase (Pm...... activity was abolished. Histidine in this position is conserved in α-2,6-sialyltransferases and has been suggested, and recently confirmed, to be the determinant for strict regiospecificity in the sialyltransferase reaction. Our data verified this theorem. In trans-sialidase reactions, the P34H mutant...... displayed a distinct preference for 6'-sialyllactose synthesis but low levels of 3'-sialyllactose were also produced. The sialyllactose yield was however lower than when using PmSTWT under optimal conditions for 6'-sialyllactose formation. The discrepancy in regiospecificity between the two reactions could...

Hydrous mineral dehydration around heat-generating nuclear waste in bedded salt formations.

Science.gov (United States)

Jordan, Amy B; Boukhalfa, Hakim; Caporuscio, Florie A; Robinson, Bruce A; Stauffer, Philip H

2015-06-02

Heat-generating nuclear waste disposal in bedded salt during the first two years after waste emplacement is explored using numerical simulations tied to experiments of hydrous mineral dehydration. Heating impure salt samples to temperatures of 265 °C can release over 20% by mass of hydrous minerals as water. Three steps in a series of dehydration reactions are measured (65, 110, and 265 °C), and water loss associated with each step is averaged from experimental data into a water source model. Simulations using this dehydration model are used to predict temperature, moisture, and porosity after heating by 750-W waste canisters, assuming hydrous mineral mass fractions from 0 to 10%. The formation of a three-phase heat pipe (with counter-circulation of vapor and brine) occurs as water vapor is driven away from the heat source, condenses, and flows back toward the heat source, leading to changes in porosity, permeability, temperature, saturation, and thermal conductivity of the backfill salt surrounding the waste canisters. Heat pipe formation depends on temperature, moisture availability, and mobility. In certain cases, dehydration of hydrous minerals provides sufficient extra moisture to push the system into a sustained heat pipe, where simulations neglecting this process do not.

Mechanisms and prevention of plant tissue collapse during dehydration: a critical review.

Science.gov (United States)

Prothon, Frédéric; Ahrné, Lilia; Sjöholm, Ingegerd

2003-01-01

The appearance and functional properties are primordial in the quality assessment of semifinished fruit and vegetable products. These properties are often associated with shrunken, shriveled, darkened materials of poor rehydration ability after been subjected to air-drying--the most used drying method in the food industry. Fruits and vegetables are cellular tissues containing gas-filled pores that tend to collapse when subjected to dehydration. Collapse is an overall term that has different meanings and scale-settings in the literature depending on whether the author is a plant physiologist, a food technologist, a chemical engineer, or a material scientist. Some clarifications are given in this particular but wide field. The purpose of this work was to make a state-of-the-art contribution to the structural and textural effects of different types of dehydration on edible plant products and give a basis for preventing this phenomenon. The plant tissue is described, and the primordial role of the cell wall in keeping the structural integrity is emphasized. Water and its functionality at macro and micro levels of the cellular tissue are reviewed as well as its transport during dehydration. The effects of both dehydration and rehydration are described in detail, and the term "textural collapse" is proposed as an alternative to structural collapse.

Effect of process variables on the osmotic dehydration of star-fruit slices

Directory of Open Access Journals (Sweden)

Camila Dalben Madeira Campos

2012-06-01

Full Text Available The objective of this work was to study the effect of blanching and the influence of temperature, solution concentration, and the initial fruit:solution ratio on the osmotic dehydration of star-fruit slices. For blanching, different concentrations of citric and ascorbic acids were studied. The samples immersed in 0.75% citric acid presented little variation in color in relation to the fresh star-fruit. Osmotic dehydration was carried out in an incubator with orbital shaking, controlled temperature, and constant shaking at 120 rpm. The influence of process variables was studied in trials defined by a complete 23 central composite design. In general, water loss and solids gain were positively influenced by temperature and by solution concentration. Nevertheless, lower temperatures reduced water loss throughout the osmotic dehydration process. An increase in the amount of dehydrating solution (initial fruit:solution ratio slightly influenced the evaluated responses. The process carried out at 50 ºC with a solution concentration of 50% resulted in a product with lower solids gain and greater water loss. Under these conditions, blanching minimized the effect of the osmotic treatment on star-fruit browning, and therefore the blanched fruits showed little variation in color in relation to the fresh fruit.

Palladium-catalyzed cyclization reactions of 2-vinylthiiranes with heterocumulenes. Regioselective and enantioselective formation of thiazolidine, oxathiolane, and dithiolane derivatives.

Science.gov (United States)

Larksarp, C; Sellier, O; Alper, H

2001-05-18

The first palladium-catalyzed ring-expansion reaction of 2-vinylthiiranes with heterocumulenes to form sulfur-containing five-membered-ring heterocycles is described. This regioselective reaction requires 5 mol % of Pd(2)(dba)(3).CHCl(3) and 10 mol % of bidendate phosphine ligand (dppp, BINAP), at 50-80 degrees C, in THF. The reaction of 2-vinylthiiranes with carbodiimides, isocyanates, and ketenimines affords 1,3-thiazolidine derivatives, whereas the reaction with diphenylketene or isothiocyanates results in the formation of 1,3-oxathiolane or 1,3-dithiolane compounds in good to excellent isolated yields and in up to 78% ee.

Dehydration of 2-Methyl-1-Cyclohexanol: New Findings from a Popular Undergraduate Laboratory Experiment

Science.gov (United States)

Friesen, J. Brent; Schretzman, Robert

2011-01-01

The mineral acid-catalyzed dehydration of 2-methyl-1-cyclohexanol has been a popular laboratory exercise in second-year organic chemistry for several decades. The dehydration experiment is often performed by organic chemistry students to illustrate Zaitsev's rule. However, sensitive analytical techniques reveal that the results do not entirely…

Synthesis and characterization of poly(lactic acid)/ montmorillonite nanocomposites by in situ polycondensation catalyzed by non-metal-based compound.

Science.gov (United States)

Kaewprapan, Kulwadee; Phattanarudee, Siriwan

2012-01-01

Poly(lactic acid)/montmorillonite nanocomposites were prepared by using non-toxic catalysts, i.e., phthalic acid and succinimide, via in situ polycondensation in presence of silicate. Concentrations of catalysts and clay were varied in a range of 0-3% wt and 0-0.5% wt, respectively. The reaction condition was controlled at 180 degrees C for 24 hr under a reduced pressure. Viscosity average molecular weight of the synthesized polymers and nanocomposites were characterized and compared using an Ubbelohde viscometer. Pattern of silicate distribution in the composites was investigated by X-ray diffraction to correlate with thermal properties evaluated by differential scanning calorimetry and thermogravimetric analysis. The results showed that the addition of catalysts at 2% wt gave the highest product yield (55-60%). The presence of silicate affected on molecular weight reduction, and the diffracted patterns suggested an intercalated structure. With a small amount of added filler, a significant improvement in thermal property and crystallinity of the resultant composites was obtained compared to those of the catalyzed polymers, in which the composites with succinimide exhibited overall better thermal stability and higher crystallinity than the ones prepared with phthalic acid.

Dehydration-induced release of vasopressin involves activation of hypothalamic histaminergic neurons.

Science.gov (United States)

Kjaer, A; Knigge, U; Rouleau, A; Garbarg, M; Warberg, J

1994-08-01

The hypothalamic neurotransmitter histamine (HA) induces arginine vasopressin (AVP) release when administered centrally. We studied and characterized this effect of HA with respect to receptor involvement. In addition, we studied the possible role of hypothalamic histaminergic neurons in the mediation of a physiological stimulus (dehydration) for AVP secretion. Intracerebroventricular administration of HA, the H1-receptor agonists 2(3-bromophenyl)HA and 2-thiazolylethylamine, or the H2-receptor agonists amthamine or 4-methyl-HA stimulated AVP secretion. The stimulatory action of HA on AVP was inhibited by pretreatment with the H1-receptor antagonist mepyramine or the H2-receptor antagonist cimetidine. Twenty-four hours of dehydration elevated the plasma osmolality from 298 +/- 3 to 310 +/- 3 mmol/liter and increased the plasma AVP concentration 4-fold. The hypothalamic content of HA and its metabolite tele-methyl-HA was elevated in response to dehydration, indicating an increased synthesis and release of hypothalamic HA. Dehydration-induced AVP secretion was lowered when neuronal HA synthesis was inhibited by the administration of (S) alpha-fluoromethylhistidine or when the animals were pretreated with the H3-receptor agonist R(alpha)methylhistamine, which inhibits the release and synthesis of HA, the H1-receptor antagonists mepyramine and cetirizine, or the H2-receptor antagonists cimetidine and ranitidine. We conclude that HA, via activation of both H1- and H2-receptors, stimulates AVP release and that HA is a physiological regulator of AVP secretion.

Dehydration accelerates reductions in cerebral blood flow during prolonged exercise in the heat without compromising brain metabolism.

Science.gov (United States)

Trangmar, Steven J; Chiesa, Scott T; Llodio, Iñaki; Garcia, Benjamin; Kalsi, Kameljit K; Secher, Niels H; González-Alonso, José

2015-11-01

Dehydration hastens the decline in cerebral blood flow (CBF) during incremental exercise, whereas the cerebral metabolic rate for O2 (CMRO2 ) is preserved. It remains unknown whether CMRO2 is also maintained during prolonged exercise in the heat and whether an eventual decline in CBF is coupled to fatigue. Two studies were undertaken. In study 1, 10 male cyclists cycled in the heat for ∼2 h with (control) and without fluid replacement (dehydration) while internal and external carotid artery blood flow and core and blood temperature were obtained. Arterial and internal jugular venous blood samples were assessed with dehydration to evaluate CMRO2 . In study 2, in 8 male subjects, middle cerebral artery blood velocity was measured during prolonged exercise to exhaustion in both dehydrated and euhydrated states. After a rise at the onset of exercise, internal carotid artery flow declined to baseline with progressive dehydration (P dehydration accelerates the decline in CBF without affecting CMRO2 and also restricts extracranial perfusion. Thus, fatigue is related to a reduction in CBF and extracranial perfusion rather than CMRO2 . Copyright © 2015 the American Physiological Society.

Comparative study of the loss of vitamin C in chalarina (Casimiroa edulis by four methods of dehydration

Directory of Open Access Journals (Sweden)

Judith Castañeda

2010-03-01

Full Text Available The aim of this study was to compare the loss of chalarina vitamin C after applying four methods of dehydration: vacuum osmotic dehydration combined with convective drying, convective drying, osmotic dehydration combined with vacuum freeze-drying, and freeze-drying. The fresh chalarina was fitted into cubes of 1 cm; we determined the vitamin C content and other chemical properties of the pulp. The powders were characterized: vitamin C, moisture content, aw, density, angle of flow and compressibility. Fresh chalarina pulp has a vitamin C content of 29.75 mg/100g. Osmotic dehydration and vacuum reduced to 15.75 mg/100g this content; combined with convective drying is reached 9.31 mg/100g; if combined with freeze-drying is obtained 14.98 mg/100g. Applying convective drying was obtained only 7.05 mg of vitaminaC/100g chalarina powder, while by applying only freeze-drying was obtained 23.63 mg/100g. We conclude that the powder obtained by vacuum osmotic dehydration - convective drying has better physical and chemical characteristics of powders obtained with other methods of dehydration.

Identification of Cis-Acting Promoter Elements in Cold- and Dehydration-Induced Transcriptional Pathways in Arabidopsis, Rice, and Soybean

Science.gov (United States)

Maruyama, Kyonoshin; Todaka, Daisuke; Mizoi, Junya; Yoshida, Takuya; Kidokoro, Satoshi; Matsukura, Satoko; Takasaki, Hironori; Sakurai, Tetsuya; Yamamoto, Yoshiharu Y.; Yoshiwara, Kyouko; Kojima, Mikiko; Sakakibara, Hitoshi; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2012-01-01

The genomes of three plants, Arabidopsis (Arabidopsis thaliana), rice (Oryza sativa), and soybean (Glycine max), have been sequenced, and their many genes and promoters have been predicted. In Arabidopsis, cis-acting promoter elements involved in cold- and dehydration-responsive gene expression have been extensively analysed; however, the characteristics of such cis-acting promoter sequences in cold- and dehydration-inducible genes of rice and soybean remain to be clarified. In this study, we performed microarray analyses using the three species, and compared characteristics of identified cold- and dehydration-inducible genes. Transcription profiles of the cold- and dehydration-responsive genes were similar among these three species, showing representative upregulated (dehydrin/LEA) and downregulated (photosynthesis-related) genes. All (46 = 4096) hexamer sequences in the promoters of the three species were investigated, revealing the frequency of conserved sequences in cold- and dehydration-inducible promoters. A core sequence of the abscisic acid-responsive element (ABRE) was the most conserved in dehydration-inducible promoters of all three species, suggesting that transcriptional regulation for dehydration-inducible genes is similar among these three species, with the ABRE-dependent transcriptional pathway. In contrast, for cold-inducible promoters, the conserved hexamer sequences were diversified among these three species, suggesting the existence of diverse transcriptional regulatory pathways for cold-inducible genes among the species. PMID:22184637

Carbon-based building blocks for alcohol dehydration

DEFF Research Database (Denmark)

Boffa, Vittorio; Mallon, Peter E.; Magnacca, Giuliana

A biopolymer (HAL), extracted from organic compost with yield ~20%, was used to fabricate composite HAL-graphene oxide (GO) membranes. Upon thermal stabilization, HAL brings high disorder in the membrane structure, thus increasing water permeability. This feature together with the good water/etha....../ethanol perm-selectivity make GO-HAL membranes promising devices for alcohol dehydration....

Methods for dehydration of sugars and sugar alcohols

Science.gov (United States)

Holladay, Johnathan E [Kennewick, WA; Hu, Jianli [Kennewick, WA; Zhang, Xinjie [Burlington, MA; Wang, Yong [Richland, WA

2010-08-10

The invention includes a method of dehydration of a sugar using a dehydration catalyst and a co-catalyst within a reactor. A sugar is introduced and H.sub.2 is flowed through the reactor at a pressure of less than or equal to about 300 psig to convert at least some of the sugar into an anhydrosugar product. The invention includes a process for producing isosorbide. A starting material comprising sorbitol is flowed into a reactor. H.sub.2 is counter flowed through the reactor. The starting material is exposed to a catalyst in the presence of a co-catalyst which comprises at least one metal. The exposing is conducted at a hydrogen pressure of less than or equal to 300 psig within the reactor and the hydrogen removes at least some of any water present during the exposing and inhibits formation of colored byproducts.

A RhABF2/Ferritin module affects rose (Rosa hybrida) petal dehydration tolerance and senescence by modulating iron levels.

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Liu, Jitao; Fan, Youwei; Zou, Jing; Fang, Yiqun; Wang, Linghao; Wang, Meng; Jiang, Xinqiang; Liu, Yiqing; Gao, Junping; Zhang, Changqing

2017-12-01

Plants often develop the capacity to tolerate moderate and reversible environmental stresses, such as drought, and to re-establish normal development once the stress has been removed. An example of this phenomenon is provided by cut rose (Rosa hybrida) flowers, which experience typical reversible dehydration stresses during post-harvest handling after harvesting at the bud stages. The molecular mechanisms involved in rose flower dehydration tolerance are not known, however. Here, we characterized a dehydration- and abscisic acid (ABA)-induced ferritin gene (RhFer1). Dehydration-induced free ferrous iron (Fe 2+ ) is preferentially sequestered by RhFer1 and not transported outside of the petal cells, to restrict oxidative stresses during dehydration. Free Fe 2+ accumulation resulted in more serious oxidative stresses and the induction of genes encoding antioxidant enzyme in RhFer1-silenced petals, and poorer dehydration tolerance was observed compared with tobacco rattle virus (TRV) controls. We also determined that RhABF2, an AREB/ABF transcription factor involved in the ABA signaling pathway, can activate RhFer1 expression by directly binding to its promoter. The silencing of RhABF2 decreased dehydration tolerance and disrupted Fe homeostasis in rose petals during dehydration, as did the silencing of RhFer1. Although both RhFer1 and Fe transporter genes are induced during flower natural senescence in plants, the silencing of RhABF2 or RhFer1 accelerates the petal senescence processes. These results suggest that the regulatory module RhABF2/RhFer1 contributes to the maintenance of Fe levels and enhances dehydration tolerance through the action of RhFer1 locally sequestering free Fe 2+ under dehydration conditions, and plays synergistic roles with transporter genes during flower senescence. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Comparing the Accuracy of the Three Dehydration Scales in Children with Acute Diarrhea in a Developing Country of Kosovo.

Science.gov (United States)

Hoxha, Teuta; Xhelili, Luan; Azemi, Mehmedali; Avdiu, Muharrem; Ismaili-Jaha, Vlora; Efendija-Beqa, Urata; Grajcevci-Uka, Violeta

2015-06-01

Although diarrhea is a preventable disease, it remains the second leading cause of death (after pneumonia) among children aged under five years worldwide. The World Health Organization (WHO) scale, the Gorelick scale, and the Clinical Dehydration Scale (CDS) were created to estimate dehydration status using clinical signs. The purpose of this study is to determine whether these clinical scales can accurately assess dehydration status of children in a developing country of Kosovo. Children aged 1 month to 5 years with a history of acute diarrhea were enrolled in the study. After recording the data about the patients historical features the treating physician recorded the physical examination findings consistent with each clinical score. Receiver operating characteristic (ROC) curves were constructed to evaluate the performance of the three scales, compared to the gold standard, percent weight change with rehydration. Sensitivity, specificity and likelihood ratios were calculated using the best cut-off points of the ROC curves. We enrolled 230 children, and 200 children met eligibility criteria. The WHO scale for predicting significant dehydration (≥5 percent weight change) had an area under the curve (AUC) of 0.71 (95% : CI= 0.65-0.77). The Gorelick scales 4- and 10-point for predicting significant dehydration, had an area under the curve of 0.71 (95% : CI=0.63- 0.78) and 0.74 (95% : CI= 0.68-0.81) respectively. Only the CDS for predicting the significant dehydration above ≥6% percent weight change, did not have an area under the curve statistically different from the reference line with an AUC of 0.54 (95% CI = 0.45- 0.63). The WHO dehydration scale and Gorelick scales were fair predictors of dehydration in children with diarrhea. Only the Clinical Dehydration Scale was found not to be a helpful predictor of dehydration in our study cohort.

Comparing the Accuracy of the Three Dehydration Scales in Children with Acute Diarrhea in a Developing Country of Kosovo

Science.gov (United States)

Hoxha, Teuta; Xhelili, Luan; Azemi, Mehmedali; Avdiu, Muharrem; Ismaili-Jaha, Vlora; Efendija-Beqa, Urata; Grajcevci-Uka, Violeta

2015-01-01

Background. Although diarrhea is a preventable disease, it remains the second leading cause of death (after pneumonia) among children aged under five years worldwide. The World Health Organization (WHO) scale, the Gorelick scale, and the Clinical Dehydration Scale (CDS) were created to estimate dehydration status using clinical signs. The purpose of this study is to determine whether these clinical scales can accurately assess dehydration status of children in a developing country of Kosovo. Methodology. Children aged 1 month to 5 years with a history of acute diarrhea were enrolled in the study. After recording the data about the patients historical features the treating physician recorded the physical examination findings consistent with each clinical score. Receiver operating characteristic (ROC) curves were constructed to evaluate the performance of the three scales, compared to the gold standard, percent weight change with rehydration. Sensitivity, specificity and likelihood ratios were calculated using the best cut-off points of the ROC curves. Results. We enrolled 230 children, and 200 children met eligibility criteria. The WHO scale for predicting significant dehydration (≥5 percent weight change) had an area under the curve (AUC) of 0.71 (95% : CI= 0.65-0.77). The Gorelick scales 4- and 10-point for predicting significant dehydration, had an area under the curve of 0.71 (95% : CI=0.63- 0.78) and 0.74 (95% : CI= 0.68-0.81) respectively. Only the CDS for predicting the significant dehydration above ≥6% percent weight change, did not have an area under the curve statistically different from the reference line with an AUC of 0.54 (95% CI = 0.45- 0.63). Conclusion. The WHO dehydration scale and Gorelick scales were fair predictors of dehydration in children with diarrhea. Only the Clinical Dehydration Scale was found not to be a helpful predictor of dehydration in our study cohort. PMID:26244042

Sex differences and plasticity in dehydration tolerance: insight from a tropical liverwort

OpenAIRE

Marks, Rose A.; Burton, James F.; McLetchie, D. Nicholas

2016-01-01

Background and Aims Adaptations allowing plants to cope with drying are particularly relevant in the light of predicted climate change. Dehydration tolerance (DhT, also dehydration-tolerant) is one such adaptation enabling tissue to survive substantial drying. A great deal of work has been conducted on highly DhT species. However, bryophytes showing less intense and variable DhT are understudied, despite the potential for these species to provide an informative link between highly tolerant an...

Osmotic dehydration of fruit and berry raw materials in the food industry

OpenAIRE

N. A. Gribova; L. G. Eliseeva

2017-01-01

Osmotic dehydration has recently received more attention as an effective method of preserving fruits and berries. Osmosis is a simple process that facilitates the processing of fruits and berries in order to preserve the original characteristics, namely nutritional value and organoleptic properties: color, aroma and texture. Osmotic dehydration has found wide application in the preservation of food products, as the activity of water in fruits and berries decreases, in some of them up to 90% o...

Mass transfer kinetics during osmotic dehydration of pomegranate arils.

Science.gov (United States)

Mundada, Manoj; Hathan, Bahadur Singh; Maske, Swati

2011-01-01

The mass transfer kinetics during osmotic dehydration of pomegranate arils in osmotic solution of sucrose was studied to increase palatability and shelf life of arils. The freezing of the whole pomegranate at -18 °C was carried out prior to osmotic dehydration to increase the permeability of the outer cellular layer of the arils. The osmotic solution concentrations used were 40, 50, 60°Bx, osmotic solution temperatures were 35, 45, 55 °C. The fruit to solution ratio was kept 1:4 (w/w) during all the experiments and the process duration varied from 0 to 240 min. Azuara model and Peleg model were the best fitted as compared to other models for water loss and solute gain of pomegranate arils, respectively. Generalized Exponential Model had an excellent fit for water loss ratio and solute gain ratio of pomegranate arils. Effective moisture diffusivity of water as well as solute was estimated using the analytical solution of Fick's law of diffusion. For above conditions of osmotic dehydration, average effective diffusivity of water loss and solute gain varied from 2.718 × 10(-10) to 5.124 × 10(-10) m(2)/s and 1.471 × 10(-10) to 5.147 × 10(-10) m(2)/s, respectively. The final product was successfully utilized in some nutritional formulations such as ice cream and bakery products.

The effects of dehydration, moderate alcohol consumption, and rehydration on cognitive functions.

Science.gov (United States)

Irwin, Christopher; Leveritt, Michael; Shum, David; Desbrow, Ben

2013-05-01

This study investigated the impact of mild-moderate dehydration on alcohol-induced deteriorations in cognitive functions. Sixteen healthy males participated in a single-blind, placebo-controlled cross-over design study involving 4 experimental trials (separated by ≥7 d). In each trial, participants were dehydrated by 2.5% body mass through exercise. After 1 h recovery in a thermo-neutral environment (22 ± 2 °C, 60-70% relative humidity) 4 tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were administered to the participants (test 1). In two of the trials, participants were provided with water equivalent to either 50% or 150% body mass loss and given salt (NaCl) capsules (50 mmol/L). A set volume of alcohol or placebo was then consumed in each trial, incorporating the conditions: dehydration-placebo (DP), dehydration-alcohol (DA), partial rehydration-alcohol (PA), and full rehydration-alcohol (FA). The same 4 CANTAB tasks were then re-administered (test 2). Subjective ratings of mood and estimates of alcohol intoxication and driving impairment were also recorded in each trial. Alcohol consumption caused deterioration on 3 of the 4 CANTAB measures (viz., choice reaction time, executive function and response inhibition). This reduction in performance was exacerbated when participants were dehydrated compared to trials where full rehydration occurred. Subjective ratings of impairment and intoxication were not significantly different between any of the trials where alcohol was consumed; however ratings for alcohol trials were significantly higher than in the placebo trial. These findings suggest that rehydration after exercise that causes fluid loss can attenuate alcohol-related deterioration of cognitive functions. This may pose implications for post match fluid replacement if a moderate amount of alcohol is also consumed. Copyright © 2013 Elsevier Inc. All rights reserved.

Evaluation of neutrophil gelatinase-associated lipocalin in pediatric patients with acute rotavirus gastroenteritis and dehydration.

Science.gov (United States)

Çelik, Tanju; Altekin, Emel; İşgüder, Rana; Kenesari, Yasin; Duman, Murat; Arslan, Nur

2013-09-03

Dehydration caused by acute rotavirus gastroenteritis is a frequent finding in pediatric patients. The most important treatment modality in these patients is recognising and treating dehydration, electrolyte imbalance and acute kidney injury. Neutrophil gelatinase-associated lipocalin (NGAL) is used widely as a biomarker for the diagnosis of acute or chronic renal injury in numerous clinical studies. It is recognized as an early marker of acute renal failure before the elevation of routine biochemical tests such as creatinine. The aim of this study is to investigate the plasma and urine NGAL concentrations in mildly or moderately dehydrated patients with acute rotavirus gastroenteritis. A total of 30 patients (13 girls, mean age 62.5 ± 46.2 months) with diarrhea and mild/moderate dehydration and 35 healthy controls (17 girls, mean age 81.1 ± 41.8 months) were enrolled in the study. Plasma and urine NGAL levels of the two groups were compared. The mean age, gender and serum creatinine levels of the patients and healthy controls were similar. The mean plasma and urine NGAL levels of the patients were significantly higher than controls (plasma: 118.6 ± 81.2 vs. 66.5 ± 11.3, p = 0.001 and urine: 17.7 ± 17.5 vs. 10.6 ± 7.9, p = 0.035, respectively). Mildly or moderately dehydrated children have higher plasma and urine NGAL levels compared to control subjects. Plasma and/or urine NGAL levels can be used for the early prediction of renal impairment in children with mild or moderate dehydration.

Evolution of microstructure and elastic wave velocities in dehydrated gypsum samples

Science.gov (United States)

Milsch, Harald; Priegnitz, Mike

2012-12-01

We report on changes in P and S-wave velocities and rock microstructure induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air, at ambient pressure, and temperatures between 378 and 423 K. Dehydration did not proceed homogeneously but via a reaction front moving sample inwards separating an outer highly porous rim from the remaining gypsum which, above approximately 393 (±5) K, concurrently decomposed into hemihydrate. Overall porosity was observed to continuously increase with reaction progress from approximately 2% for fully hydrated samples to 30% for completely dehydrated ones. Concurrently, P and S-wave velocities linearly decreased with porosity from 5.2 and 2.7 km/s to 1.0 and 0.7 km/s, respectively. It is concluded that a linearized empirical Raymer-type model extended by a critical porosity term and based on the respective time dependent mineral and pore volumes reasonably replicates the P and S-wave data in relation to reaction progress and porosity.

Theoretical investigation of the selective dehydration and dehydrogenation of ethanol catalyzed by small molecules.

Science.gov (United States)

Wang, Yanqun; Tang, Yizhen; Shao, Youxiang

2017-09-01

Catalytic dehydration and dehydrogenation reactions of ethanol have been investigated systematically using the ab initio quantum chemistry methods The catalysts include water, hydrogen peroxide, formic acid, phosphoric acid, hydrogen fluoride, ammonia, and ethanol itself. Moreover, a few clusters of water and ethanol were considered to simulate the catalytic mechanisms in supercritical water and supercritical ethanol. The barriers for both dehydration and dehydrogenation can be reduced significantly in the presence of the catalysts. It is revealed that the selectivity of the catalytic dehydration and dehydrogenation depends on the acidity and basicity of the catalysts and the sizes of the clusters. The acidic catalyst prefers dehydration while the basic catalysts tend to promote dehydrogenation more effectively. The calculated water-dimer catalysis mechanism supports the experimental results of the selective oxidation of ethanol in the supercritical water. It is suggested that the solvent- and catalyst-free self-oxidation of the supercritical ethanol could be an important mechanism for the selective dehydrogenation of ethanol on the theoretical point of view. Copyright © 2017 Elsevier Inc. All rights reserved.

Severe Hypernatremic Dehydration and Lower Limb Gangrene in an Infant Exposed to Lamotrigine, Aripiprazole, and Sertraline in Breast Milk.

Science.gov (United States)

Morin, Caroline; Chevalier, Isabelle

Hypernatremic dehydration is well described in exclusively breastfed neonates, although life-threatening complications are rarely reported. The present article describes a case of severe hypernatremic dehydration in a previously healthy term neonate. Other published cases of severe complications of hypernatremic dehydration are discussed. The exclusively breastfed neonate described had severe hypernatremic dehydration because of inadequate milk intake, with disseminated intravascular coagulation and right lower limb gangrene that required amputation of all five toes and surgical debridement of the metatarsals. The usual etiology of hypernatremic dehydration in this age group is insufficient breast milk intake. Here, the infant's mother was treated for bipolar disorder with lamotrigine 250 mg orally once daily, aripiprazole 15 mg orally once daily, and sertraline 100 mg orally once daily. Awareness of these complications should prompt close follow-up of the infant with poor weight gain. The role of maternal medication as a risk factor for hypernatremic dehydration among exclusively breastfed infants needs to be further explored.

Efficiency of Osmotic Dehydration of Apples in Polyols Solutions.

Science.gov (United States)

Cichowska, Joanna; Żubernik, Joanna; Czyżewski, Jakub; Kowalska, Hanna; Witrowa-Rajchert, Dorota

2018-02-17

The present study aimed to evaluate the influence of selected compounds from the polyol group, as well as other saccharides, on the osmotic dehydration process of apples. The following alternative solutions were examined: erythritol, xylitol, maltitol, inulin and oligofructose. Efficiency of the osmotic dehydration process was evaluated based on the kinetics of the process, and through comparison of the results obtained during the application of a sucrose solution. This innovative research utilizes alternative solutions in osmotic pretreatment, which until now, have not been commonly used in fruit processing by researchers worldwide. Results indicate that erythritol and xylitol show stronger or similar efficiency to sucrose; however, the use of inulin, as well as oligofructose, was not satisfactory due to the insufficient, small osmotic driving forces of the process, and the low values of mass transfer parameters.

Comparison of three dehydration scales showed that they were of limited or no value for assessing small children with acute diarrhoea.

Science.gov (United States)

Pomorska, Dominika; Dziechciarz, Piotr; Mduma, Esto; Gidion, Joshua; Falszewska, Anna; Szajewska, Hania

2018-02-20

We explored the diagnostic accuracy of the clinical dehydration scale (CDS), the World Health Organization (WHO) scale and the Gorelick scale for assessing dehydration in children admitted to a Tanzanian referral hospital. This was a prospective, observational study, carried out from April 2015 to January 2017 on children aged one month to five years admitted to the hospital with acute diarrhoea lasting less than five days. Before rehydration therapy, each patient's weight was recorded and the degree of dehydration was assessed based on the three scales. The reference standard was the percentage weight change between admission and discharge. The main outcomes were the sensitivity, specificity and positive and negative likelihood ratios (LRs) of the scales. Data from 124 eligible patients were available. The CDS showed limited value for ruling in cases with some dehydration (LR 1.9, 95% confidence interval 1.1-2.8), but was of no value in assessing no and moderate to severe dehydration. The WHO and Gorelick scales were of no value in evaluating any degree of dehydration. The WHO and Gorelick dehydration scales were no use for assessing dehydration in small children, and the CDS was of limited use for predicting cases with some dehydration. ©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Dehydration and performance on clinical concussion measures in collegiate wrestlers.

Science.gov (United States)

Weber, Amanda Friedline; Mihalik, Jason P; Register-Mihalik, Johna K; Mays, Sally; Prentice, William E; Guskiewicz, Kevin M

2013-01-01

The effects of dehydration induced by wrestling-related weight-cutting tactics on clinical concussion outcomes, such as neurocognitive function, balance performance, and symptoms, have not been adequately studied. To evaluate the effects of dehydration on the outcome of clinical concussion measures in National Collegiate Athletic Association Division I collegiate wrestlers. Repeated-measures design. Clinical research laboratory. Thirty-two Division I healthy collegiate male wrestlers (age = 20.0 ± 1.4 years; height = 175.0 ± 7.5 cm; baseline mass = 79.2 ± 12.6 kg). Participants completed preseason concussion baseline testing in early September. Weight and urine samples were also collected at this time. All participants reported to prewrestling practice and postwrestling practice for the same test battery and protocol in mid-October. They had begun practicing weight-cutting tactics a day before prepractice and postpractice testing. Differences between these measures permitted us to evaluate how dehydration and weight-cutting tactics affected concussion measures. Sport Concussion Assessment Tool 2 (SCAT2), Balance Error Scoring System, Graded Symptom Checklist, and Simple Reaction Time scores. The Simple Reaction Time was measured using the Automated Neuropsychological Assessment Metrics. The SCAT2 measurements were lower at prepractice (P = .002) and postpractice (P < .001) when compared with baseline. The BESS error scores were higher at postpractice when compared with baseline (P = .015). The GSC severity scores were higher at prepractice (P = .011) and postpractice (P < .001) than at baseline and at postpractice when than at prepractice (P = .003). The number of Graded Symptom Checklist symptoms reported was also higher at prepractice (P = .036) and postpractice (P < .001) when compared with baseline, and at postpractice when compared with prepractice (P = .003). Our results suggest that it is important for wrestlers to be evaluated in a euhydrated state to

Dehydration of isobutanol and the elimination of water from fuel alcohols.

Science.gov (United States)

Rosado-Reyes, Claudette M; Tsang, Wing; Alecu, Ionut M; Merchant, Shamel S; Green, William H

2013-08-08

Rate coefficients for the dehydration of isobutanol have been determined experimentally from comparative rate single pulse shock tube measurements and calculated via multistructural transition state theory (MS-TST). They are represented by the Arrhenius expression, k(isobutanol → isobutene + H2O)(experimental) = 7.2 × 10(13) exp(-35300 K/T) s(-1). The theoretical work leads to the high pressure rate expression, k(isobutanol → isobutene + H2O)(theory) = 3.5 × 10(13) exp(-35400 K/T) s(-1). Results are thus within a factor of 2 of each other. The experimental results cover the temperature range 1090-1240 K and pressure range 1.5-6 atm, with no discernible pressure effects. Analysis of these results, in combination with earlier single pulse shock tube work, made it possible to derive the governing factors that control the rate coefficients for alcohol dehydration in general. Alcohol dehydration rate constants depend on the location of the hydroxyl group (primary, secondary, and tertiary) and the number of available H-atoms adjacent to the OH group for water elimination. The position of the H-atoms in the hydrocarbon backbone appears to be unimportant except for highly substituted molecules. From these correlations, we have derived k(isopropanol → propene + H2O) = 7.2 × 10(13) exp(-33000 K/T) s(-1). Comparison of experimental determination with theoretical calculations for this dehydration, and those for ethanol show deviations of the same magnitude as for isobutanol. Systematic differences between experiments and theoretical calculations are common.

Stroke from systemic vascular disorders in Saudi children: The devastating role of hypernatremic dehydration

International Nuclear Information System (INIS)

Salih, Mustafa A.; Al-Jarallah, Ahmed A.; Zahraa, Jihad N.; Alorainy, Ibrahim A.; Hassan, Hamdy H.

2006-01-01

Systemic vascular disorders, leading to childhood stroke, include volume depletion or systemic hypotension and hypernatremic dehydration. We describe 3 cases of stroke following systemic vascular disorders. These were diagnosed during a prospective and retrospective study on childhood stroke, which included 104 patients. Post-gastroenteritis hypernatremic dehydration is an important, potentially preventable, cause of stroke in Saudi children. (author)

The mechanism of the dehydration reaction of solid HIO 4. 2H 2O and the role of radiation

International Nuclear Information System (INIS)

Takriti, S.

1998-01-01

A thermal and kinetic study of dehydration reaction of periodic acid dehydrate has been carried out with isothermal and physical measurements. Isothermal dehydration curves have been studied in the temperature ranges between 333 0 K respectively. Both dehydration processes involve the loss two molecules of water in the studied temperature ranges. Thermodynamic and kinetic parameters have been calculated using different physical models proposed. The data analysis illustrated that activation energy is about 1 eV for the first step and 1.2 eV for second

Empirically Derived Dehydration Scoring and Decision Tree Models for Children With Diarrhea: Assessment and Internal Validation in a Prospective Cohort Study in Dhaka, Bangladesh.

Science.gov (United States)

Levine, Adam C; Glavis-Bloom, Justin; Modi, Payal; Nasrin, Sabiha; Rege, Soham; Chu, Chieh; Schmid, Christopher H; Alam, Nur H

2015-08-18

Diarrhea remains one of the most common and most deadly conditions affecting children worldwide. Accurately assessing dehydration status is critical to determining treatment course, yet no clinical diagnostic models for dehydration have been empirically derived and validated for use in resource-limited settings. In the Dehydration: Assessing Kids Accurately (DHAKA) prospective cohort study, a random sample of children under 5 with acute diarrhea was enrolled between February and June 2014 in Bangladesh. Local nurses assessed children for clinical signs of dehydration on arrival, and then serial weights were obtained as subjects were rehydrated. For each child, the percent weight change with rehydration was used to classify subjects with severe dehydration (>9% weight change), some dehydration (3-9%), or no dehydration (Dehydration Score and DHAKA Dehydration Tree, respectively. Models were assessed for their accuracy using the area under their receiver operating characteristic curve (AUC) and for their reliability through repeat clinical exams. Bootstrapping was used to internally validate the models. A total of 850 children were enrolled, with 771 included in the final analysis. Of the 771 children included in the analysis, 11% were classified with severe dehydration, 45% with some dehydration, and 44% with no dehydration. Both the DHAKA Dehydration Score and DHAKA Dehydration Tree had significant AUCs of 0.79 (95% CI = 0.74, 0.84) and 0.76 (95% CI = 0.71, 0.80), respectively, for the diagnosis of severe dehydration. Additionally, the DHAKA Dehydration Score and DHAKA Dehydration Tree had significant positive likelihood ratios of 2.0 (95% CI = 1.8, 2.3) and 2.5 (95% CI = 2.1, 2.8), respectively, and significant negative likelihood ratios of 0.23 (95% CI = 0.13, 0.40) and 0.28 (95% CI = 0.18, 0.44), respectively, for the diagnosis of severe dehydration. Both models demonstrated 90% agreement between independent raters and good

Influences of dehydration on clinical features of radiological pneumonia in children attending an urban diarrhoea treatment centre in Bangladesh.

Science.gov (United States)

Chisti, M J; Salam, M A; Bardhan, P K; Ahad, R; La Vincente, S; Duke, T

2010-01-01

As the signs of dehydration often overlap with those of pneumonia, it may be difficult for health workers in resource-poor settings to make a clinical diagnosis of pneumonia in children with dehydration. This issue has received very little attention. To compare the clinical features of pneumonia in children with and without dehydration caused by diarrhoea. All children aged 2-59 months with diarrhoea and radiologically confirmed pneumonia admitted to the Special Care Ward (SCW) of Dhaka Hospital, ICDDR,B between September and December 2007 were enrolled for the study. Children with dehydration (67 cases) and those without (101 controls) were compared. Cases presented less frequently with fast breathing (60% vs 88%, pchildren with dehydration, especially when there is severe malnutrition.

Methods to increase the rate of mass transfer during osmotic dehydration of foods

OpenAIRE

Anna Chwastek

2014-01-01

Traditional methods of food preservation such as freezing, freeze drying (lyophilization), vacuum drying, convection drying are often supplemented by new technologies that enable obtaining of high quality products. Osmotic dehydration is more and more often used during processing of fruits and vegetables. This method allows maintaining good organoleptic and functional properties in the finished product. Obtaining the desired degree of dehydration or saturation of the material with an osmoacti...

Mechanism of copper(I)-catalyzed allylic alkylation of phosphorothioate esters: influence of the leaving group on α regioselectivity.

Science.gov (United States)

Sheng, Wenhao; Wang, Mian; Lein, Matthias; Jiang, Linbin; Wei, Wanxing; Wang, Jianyi

2013-10-11

The mechanism of Cu(I) -catalyzed allylic alkylation and the influence of the leaving groups (OPiv, SPiv, Cl, SPO(OiPr)2 ; Piv: pivavloyl) on the regioselectivity of the reaction have been explored by using density functional theory (DFT). A comprehensive comparison of many possible reaction pathways shows that [(iPr)2 Cu](-) prefers to bind first oxidatively to the double bond of the allylic substrate at the anti position with respect to the leaving group, and this is followed by dissociation of the leaving group. If the leaving group is not taken into account, the reaction then undergoes an isomerization and a reductive elimination process to give the α- or γ-selective product. If OPiv, SPiv, Cl, or SPO(OiPr)2 groups are present, the optimal route for the formation of both α- and γ-substituted products changes from the stepwise elimination to the direct process, in which the leaving group plays a stabilizing role for the reactant and destabilizes the transition state. The differences to the energy barrier for the α- and γ-substituted products are 2.75 kcal mol(-1) with SPO(OiPr)2 , 2.44 kcal mol(-1) with SPiv, 2.33 kcal mol(-1) with OPiv, and 1.98 kcal mol(-1) with Cl, respectively; these values show that α regioselectivity in the allylic alkylation follows a SPO(OiPr)2 >SPiv>OPiv>Cl trend, which is in satisfactory agreement with the experimental findings. This trend mainly originates in the differences between the attractive electrostatic forces and the repelling steric interactions of the SPO(OiPr)2 , SPiv, OPiv, and Cl groups on the Cu group. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Usefulness of Clinical and Laboratory Parameters for Predicting Severity of Dehydration in Children with Acute Gastroenteritis

OpenAIRE

Hoxha, Teuta Faik; Azemi, Mehmedali; Avdiu, Muharrem; Ismaili-jaha, Vlora; Grajqevci, Violeta; Petrela, Ela

2014-01-01

ABSTRACT Background: An accurate assessment of the degree of dehydration in infants and children is important for proper decision-making and treatment. This emphasizes the need for laboratory tests to improve the accuracy of clinical assessment of dehydration. The aim of this study was to assess the relationship between clinical and laboratory parameters in the assessment of dehydration. Methods: We evaluated prospectively 200 children aged 1 month to 5 years who presented with diarrhea, vomi...

Presence and dehydration of ikaite, calcium carbonate hexahydrate, in frozen shrimp shell.

Science.gov (United States)

Mikkelsen, A; Andersen, A B; Engelsen, S B; Hansen, H C; Larsen, O; Skibsted, L H

1999-03-01

Ikaite, calcium carbonate hexahydrate, has by means of X-ray diffraction analyses of frozen samples been identified as the mineral component of the white spots formed in the shell of frozen shrimp during storage. When the shrimp thaw and the shell material is dried and kept at room temperature, ikaite rapidly transforms into a mixture of anhydrous calcium carbonate forms. X-ray diffraction analyses and Raman spectra of synthetic ikaite as well as the dehydration product confirm the assignments, and the rate constant for dehydration is approximately 7 x 10(-)(4) s(-)(1) at ambient temperature. Differential scanning calorimetry showed that dehydration of synthetic ikaite is an entropy-driven, athermal process and confirms that a single first-order reaction is rate-determining. Ikaite is found to be stable in aqueous solution at temperatures below 5 degrees C and in the shell of frozen shrimps but decomposes on thawing to form anhydrous calcium carbonates.

Theoretical Study of 1,3-Dipolar Cycloadditions Regioselectivity of Benzyl Azide with Glycosyl-O Acetylene Using Density Functional Theory (DFT

Directory of Open Access Journals (Sweden)

Adib Ghaleb

2017-12-01

Full Text Available A theoretical study of 1,3-cycloaddition has been carried out using density functional theory (DFT methods at the B3LYP/6-31G* level. The regioselectivity of the reaction have been clarified through different theoretical approaches: Case of a Two-Center Process (Domingo approach, HSAB principle (Gazquez and Mendez approach, and the activation energy calculations. The analysis of results shows that the reaction takes place along concerted asynchronous mechanism and the isomer meta is favored, in agreement with the experiment results. DOI: http://dx.doi.org/10.17807/orbital.v9i5.1017 

Pervaporation : membranes and models for the dehydration of ethanol

NARCIS (Netherlands)

Spitzen, Johannes Wilhelmus Franciscus

1988-01-01

In this thesis the dehydration of ethanol/water mixtures by pervaporation using homogeneous membranes is studied. Both the general transport mechanism as well as the development of highly selective membranes for ethanol/water separation are investigated.

Microwave promoted simple, efficient and regioselective synthesis of trisubstituted imidazo[1,2-a]benzimidazoles on soluble support.

Science.gov (United States)

Chen, Li-Hsun; Hsiao, Ya-Shan; Yellol, Gorakh S; Sun, Chung-Ming

2011-03-14

An efficient microwave-assisted and soluble polymer-supported synthesis of medicinally important imidazole-fused benzimidazoles has been developed. The protocol involves the rapid condensation of polymer-bound amino benzimidazoles with various α-bromoketones and subsequent in situ intramolecular cyclization under microwave irradiation resulting in a one pot synthesis of imidazole interlacing benzimidazole polymer conjugates. The condensed product was obtained with excellent regioselectivity. The biologically interesting imidazo[1,2-a]benzimidazoles was released from polymer support at ambient temperature. Diversity in the triheterocyclic nucleus was achieved by the different substitutions at its 2, 3, and 9 positions. The new protocol has the advantages of short reaction time, easy workup process, excellent yields, reduced environmental impact, wide substrate scope and convenient procedure.

Characterization of the Promoter Region of an Arabidopsis Gene for 9-cis-Epoxycarotenoid Dioxygenase Involved in Dehydration-Inducible Transcription

Science.gov (United States)

Behnam, Babak; Iuchi, Satoshi; Fujita, Miki; Fujita, Yasunari; Takasaki, Hironori; Osakabe, Yuriko; Yamaguchi-Shinozaki, Kazuko; Kobayashi, Masatomo; Shinozaki, Kazuo

2013-01-01

Plants respond to dehydration stress and tolerate water-deficit status through complex physiological and cellular processes. Many genes are induced by water deficit. Abscisic acid (ABA) plays important roles in tolerance to dehydration stress by inducing many stress genes. ABA is synthesized de novo in response to dehydration. Most of the genes involved in ABA biosynthesis have been identified, and they are expressed mainly in leaf vascular tissues. Of the products of such genes, 9-cis-epoxycarotenoid dioxygenase (NCED) is a key enzyme in ABA biosynthesis. One of the five NCED genes in Arabidopsis, AtNCED3, is significantly induced by dehydration. To understand the regulatory mechanism of the early stages of the dehydration stress response, it is important to analyse the transcriptional regulatory systems of AtNCED3. In the present study, we found that an overlapping G-box recognition sequence (5′-CACGTG-3′) at −2248 bp from the transcriptional start site of AtNCED3 is an important cis-acting element in the induction of the dehydration response. We discuss the possible transcriptional regulatory system of dehydration-responsive AtNCED3 expression, and how this may control the level of ABA under water-deficit conditions. PMID:23604098

Comparative study of the loss of vitamin C in chalarina (Casimiroa edulis) by four methods of dehydration

OpenAIRE

Judith Castañeda; Hubert Arteaga; Raúl Siche; Gilbert Rodriguez

2010-01-01

The aim of this study was to compare the loss of chalarina vitamin C after applying four methods of dehydration: vacuum osmotic dehydration combined with convective drying, convective drying, osmotic dehydration combined with vacuum freeze-drying, and freeze-drying. The fresh chalarina was fitted into cubes of 1 cm; we determined the vitamin C content and other chemical properties of the pulp. The powders were characterized: vitamin C, moisture content, aw, density, angle of flow and compress...

Reliability of Urinary Dehydration Markers in Elite Youth Boxers.

Science.gov (United States)

Zubac, Damir; Cular, Drazen; Marusic, Uros

2018-03-01

To determine the reliability and diagnostic accuracy of noninvasive urinary dehydration markers in field-based settings on a day-to-day basis in elite adolescent amateur boxers. Sixty-nine urine samples were collected daily from 23 athletes (17.3 ± 1.9 y) during their weight-stable phase and analyzed by field and laboratory measures of hydration status. Urine osmolality (U OSM ), urine specific gravity (U SG ), total protein content (T PC ), and body-mass stability were evaluated to determine fluid balance and hydration status. Overall macronutrient and water intake were determined using dietary records. According to their anthropometric characteristics, athletes were assigned into 2 groups: lightweight (L WB ) and heavyweight (H WB ) boxers. Data presented on U OSM demonstrated a uniform increment by 11.2% ± 12.8% (L WB ) and 19.9% ± 22.7% (H WB ) (P dehydration markers. Poor correlations were found between U SG and T PC metabolites (r = .27, P = .211). Urinary dehydration markers (both U SG and U OSM ) exhibit high variability and seem to be unreliable diagnostic tools to track actual body-weight loss in real-life settings. The ad libitum fluid intake was apparently inadequate to match acute fluid loss during and after intense preparation. The applicability of a single-time-point hydration-status assessment concept may preclude accurate assessment of actual body-weight deficits in youth boxers.

Solid-vapor interactions: Influence of environmental conditions on the dehydration of carbamazepine dihydrate

OpenAIRE

Surana, Rahul; Pyne, Abira; Suryanarayanan, Raj

2003-01-01

The goal of this research was a phenomenological study of the effect of environmental factors on the dehydration behavior of carbamazepine dihydrate. Dehydration experiments were performed in an automated vapor sorption apparatus under a variety of conditions, and weight loss was monitored as a function of time. In addition to lattice water, carbamazepine dihydrate contained a significant amount of physically bound water. Based on the kinetics of water loss, it was possible to differentiate b...

DEHYDRATION OF EDIBLE MUSHROOMS (PLEUROTUS OSTREATUS)

OpenAIRE

Salas de la Torre, N.; Bazán, D.; Osorio, A.; Cornejo, O.; Carrero, E.

2014-01-01

The edible mushroom Pleurotus ostreatus have been subjected to thermal, chemical and thermal-chemical treatment. The results show that the chemical treatment produces a more effective enzymatic inactivation compared to the other two treatments. Also, the experimental study of fungi dehydration carried out at 55 ° C reveals that the critical moisture content is 10.4 kg water / kg dry solids, the equilibrium moisture is 0.22 kg water / kg of solid . Los hongos comestibles Pleurotus ostreatus...

Efficiency of Osmotic Dehydration of Apples in Polyols Solutions

Directory of Open Access Journals (Sweden)

Joanna Cichowska

2018-02-01

Full Text Available The present study aimed to evaluate the influence of selected compounds from the polyol group, as well as other saccharides, on the osmotic dehydration process of apples. The following alternative solutions were examined: erythritol, xylitol, maltitol, inulin and oligofructose. Efficiency of the osmotic dehydration process was evaluated based on the kinetics of the process, and through comparison of the results obtained during the application of a sucrose solution. This innovative research utilizes alternative solutions in osmotic pretreatment, which until now, have not been commonly used in fruit processing by researchers worldwide. Results indicate that erythritol and xylitol show stronger or similar efficiency to sucrose; however, the use of inulin, as well as oligofructose, was not satisfactory due to the insufficient, small osmotic driving forces of the process, and the low values of mass transfer parameters.

Increasing fluid intake and reducing dehydration risk in older people living in long-term care: a systematic review.

Science.gov (United States)

Bunn, Diane; Jimoh, Florence; Wilsher, Stephanie Howard; Hooper, Lee

2015-02-01

To assess the efficacy of interventions and environmental factors on increasing fluid intake or reducing dehydration risk in older people living in long-term care facilities. Systematic review of intervention and observational studies. Thirteen electronic databases were searched from inception until September 2013 in all languages. References of included papers and reviews were checked. Intervention and observational studies investigating modifiable factors to increase fluid intake and/or reduce dehydration risk in older people (≥65 years) living in long-term care facilities who could drink orally. Two reviewers independently screened, selected, abstracted data, and assessed risk of bias from included studies; narrative synthesis was performed. A total of 4328 titles and abstracts were identified, 325 full-text articles were obtained and 23 were included in the review. Nineteen intervention and 4 observational studies from 7 countries investigated factors at the resident, institutional, or policy level. Overall, the studies were at high risk of bias due to selection and attrition bias and lack of valid outcome measures of fluid intake and dehydration assessment. Reported findings from 6 of the 9 intervention studies investigating the effect of multicomponent strategies on fluid intake or dehydration described a positive effect. Components included greater choice and availability of beverages, increased staff awareness, and increased staff assistance with drinking and toileting. Implementation of the US Resident Assessment Instrument reduced dehydration prevalence from 3% to 1%, P = .01. Two smaller studies reported positive effects: one on fluid intake in 9 men with Alzheimer disease using high-contrast red cups, the other involved supplementing 13 mildly dehydrated residents with oral hydration solution over 5 days to reduce dehydration. Modifications to the dining environment, advice to residents, presentation of beverages, and mode of delivery (straw vs beaker

Dehydration treatment practices among pediatrics-trained and non-pediatrics trained emergency physicians.

Science.gov (United States)

Nunez, Jeranil; Liu, Deborah R; Nager, Alan L

2012-04-01

We sought to survey emergency physicians in the United States regarding the management of pediatric dehydration secondary to acute gastroenteritis. We hypothesized that responses from physicians with dedicated pediatric training (PT), that is, board certification in pediatrics or pediatric emergency medicine, would differ from responses of physicians with no dedicated pediatric training (non-PT). An anonymous survey was mailed to randomly selected members of the American College of Emergency Physicians and sent electronically to enrollees of Brown University pediatric emergency medicine listserv. The survey consisted of 17 multiple-choice questions based on a clinical scenario depicting a 2-year-old with acute gastroenteritis and moderate dehydration. Questions asked related to treatment preferences, practice setting, and training information. One thousand sixty-nine surveys were received: 997 surveys were used for data analysis, including 269 PT physicians and 721 non-PT physicians. Seventy-nine percent of PT physicians correctly classified the scenario patient as moderately dehydrated versus 71% of non-PT physicians (P = 0.063). Among those who correctly classified the patient, 121 PT physicians (58%) and 350 non-PT physicians (68%) would initially hydrate the patient with intravenous fluids. Pediatrics-trained physicians were more likely to initially choose oral or nasogastric hydration compared with non-PT physicians (P = 0.0127). Pediatrics-trained physicians were less likely to perform laboratory testing compared with the non-PT group (n = 92, 45%, vs n = 337, 66%; P dehydrated children, significantly more PT physicians, compared with non-PT physicians, follow established guidelines.

Coping with dehydration: sympathetic activation and regulation of glutamatergic transmission in the hypothalamic PVN

Science.gov (United States)

Bardgett, Megan E.; Chen, Qing-Hui; Guo, Qing; Calderon, Alfredo S.; Andrade, Mary Ann

2014-01-01

Autonomic and endocrine profiles of chronic hypertension and heart failure resemble those of acute dehydration. Importantly, all of these conditions are associated with exaggerated sympathetic nerve activity (SNA) driven by glutamatergic activation of the hypothalamic paraventricular nucleus (PVN). Here, studies sought to gain insight into mechanisms of disease by determining the role of PVN ionotropic glutamate receptors in supporting SNA and mean arterial pressure (MAP) during dehydration and by elucidating mechanisms regulating receptor activity. Blockade of PVN N-methyl-d-aspartate (NMDA) receptors reduced (P dehydrated (DH) (48 h water deprivation) rats, but had no effect in euhydrated (EH) controls. Blockade of PVN α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors had no effect in either group. NMDA in PVN caused dose-dependent increases of renal SNA and MAP in both groups, but the maximum agonist evoked response (Emax) of the renal SNA response was greater (P dehydration increases excitatory NMDA receptor tone in PVN. Reduced glial-mediated glutamate uptake was identified as a key contributing factor. Defective glutamate uptake in PVN could therefore be an important, but as yet unexplored, mechanism driving sympathetic hyperactivity in chronic cardiovascular diseases. PMID:24671240

Investigation into structure and dehydration dynamic of gallic acid monohydrate: A Raman spectroscopic study.

Science.gov (United States)

Cai, Qiang; Xue, Jiadan; Wang, Qiqi; Du, Yong

2018-05-02

The dehydration process of gallic acid monohydrate was carried out by heating method and characterized using Raman spectroscopic technique. Density functional theory calculation with B3LYP function is applied to simulate optimized structures and vibrational frequencies of anhydrous gallic acid and its corresponding monohydrated form. Different vibrational modes are assigned by comparison between experimental and theoretical Raman spectra of above two polymorphs. Raman spectra show that vibrational modes of the monohydrate are distinctively different from those of anhydrous one. Meanwhile, the dynamic information about dehydration process of gallic acid monohydrate could also be observed and monitored directly with the help of Raman spectral analysis. The decay rate of the characteristic band from gallic acid monohydrate and the growth rate of anhydrous one are pretty consistent with each other. It indicates that there is no intermediate present during the dehydration process of gallic acid monohydrate. The results could offer us benchmark works for identifying both anhydrous and hydrated pharmaceutical compounds, characterizing their corresponding molecular conformation within various crystalline forms, and also providing useful information about the process of dehydration dynamic at the microscopic molecular level. Copyright © 2018 Elsevier B.V. All rights reserved.

Chemical Sensor Platform for Non-Invasive Monitoring of Activity and Dehydration

Directory of Open Access Journals (Sweden)

Dmitry Solovei

2015-01-01

Full Text Available A non-invasive solution for monitoring of the activity and dehydration of organisms is proposed in the work. For this purpose, a wireless standalone chemical sensor platform using two separate measurement techniques has been developed. The first approach for activity monitoring is based on humidity measurement. Our solution uses new humidity sensor based on a nanostructured TiO2 surface for sweat rate monitoring. The second technique is based on monitoring of potassium concentration in urine. High level of potassium concentration denotes clear occurrence of dehydration. Furthermore, a Wireless Body Area Network (WBAN was developed for this sensor platform to manage data transfer among devices and the internet. The WBAN coordinator controls the sensor devices and collects and stores the measured data. The collected data is particular to individuals and can be shared with physicians, emergency systems or athletes’ coaches. Long-time monitoring of activity and potassium concentration in urine can help maintain the appropriate water intake of elderly people or athletes and to send warning signals in the case of near dehydration. The created sensor system was calibrated and tested in laboratory and real conditions as well. The measurement results are discussed.

Pectin-honey coating as novel dehydrating bioactive agent for cut fruit: Enhancement of the functional properties of coated dried fruits.

Science.gov (United States)

Santagata, Gabriella; Mallardo, Salvatore; Fasulo, Gabriella; Lavermicocca, Paola; Valerio, Francesca; Di Biase, Mariaelena; Di Stasio, Michele; Malinconico, Mario; Volpe, Maria Grazia

2018-08-30

In this paper, a novel and sustainable process for the fruit dehydration was described. Specifically, edible coatings based on pectin and honey were prepared and used as dehydrating and antimicrobial agents of cut fruit samples, in this way promoting the fruit preservation from irreversible deteriorative processes. Pectin-honey coating was tested on apple, cantaloupe melon, mango and pineapple. The analysis were performed also on uncoated dehydrated fruits (control). The coated fruit evidenced enhanced dehydration percentage, enriched polyphenol and vitamin C contents, improved antioxidant activity and volatile molecules profile. Moreover, the antimicrobial activity against Pseudomonas and Escherichia coli was assessed. Finally, morphological analysis performed on fruit fractured surface, highlighted the formation of a non-sticky and homogeneous thin layer. These outcomes suggested that the novel fruit dehydration process, performed by using pectin-honey coating, was able to both preserve the safety and quality of dehydrated fruits, and enhance their authenticity and naturalness. Copyright © 2018 Elsevier Ltd. All rights reserved.

Neutron activation analysis of trace metallic elements eluted from molecular sieves in the dehydration process of safflower oil

International Nuclear Information System (INIS)

Takasago, Masahisa; Kobayashi, Koichi; Taru, Yasunori; Takaoka, Kyo

1992-01-01

Dissolved water in safflower oil affects the autoxidation of this oil significantly. Molecular sieves were used to remove the dissolved water from the oil. This method is much simpler than that of distillation, and dissolved water can be removed to the same extent as that by distillation. But, due to the elution of many kinds of trace metallic elements in the oil dehydrated with molecular sieves, these elements were analyzed by neutron activation analysis. For a data comparison trace amounts of metallic elements in the oil dehydrated by distillation were also analyzed. Since the intensity of the γ ray-photoelectric peak of nuclide 28 Al was largest among the detected elements, this element was analyzed quantitatively and the other elements qualitatively. In safflower oil dehydrated with molecular sieves, 14 kinds of the elements (I, Br, Al, Mg, Si, V, Cl, Nd, Ta, Cr, Sb, Cs, Co, Na) were detected. Also, I, Br, Cl, Cr, Ta, Sb, and Al elements were detected in the oil dehydrated by distillation. The intensity of the photoelectric peak of nuclide except 28 Al was essentially the same as that in the oil dehydrated by distillation, but the intensity of 28 Al in the oil with molecular sieves was about 28 times stronger than that in distillation oil. In the molecular sieves, 19 impure elements in addition to the original constituents (Na, K, Al, si, O) were detected. It was Al, Na, Si, Nd, Cs, and Co along with impure elements may possibly have been eluted in the oil. Al element in safflower oil dehydrated with molecular sieves was analyzed quantitatively. 0.91 ppm of Al was detected in safflower oil. The eluted amount of Al in safflower oil dehydrated by distillation was 0.032 ppm. A larger amount of Al element was thus eluted into the oil dehydrated with molecular sieves than by distillation. (author)

Effects of Hydration-Dehydration and Iodination on Seed-Borne ...

African Journals Online (AJOL)

dehydration (HD) and Iodination (I) treatment to enhance the seed quality as well as protect it\\'s deterioration during aging. The effect of the treatments was investigated on external and internal seed-borne fungi, levels of free-fatty acids, moisture ...

Proposal for the testing of a tool for assessing the risk of dehydration in the elderly patient.

Science.gov (United States)

Bulgarelli, Ketty

2015-09-09

Dehydration is now the most common fluid and electrolyte disorder in older people. Because it is often associated with high rates of morbidity and mortality, it requires careful control and prevention in the context of a thorough primary care. The main risk factor for dehydration was the low intake of water by mouth for several reasons, such as lack of autonomy, altered mental status, decreased sensation of thirst, social and environmental problems. To this may be added an increase in fluid loss caused by fever, vomiting, diarrhoea, bleeding etc., the use of diuretics or laxatives and the onset of diseases that induce an increase in the loss of urine (e.g. diabetes). This paper aims to locate a tool for assessing the risk among those reported in the literature that is easy to use for the nurse and to experiment with it on a sample of patients. An analysis of the literature showed the reliability of an instrument for assessing the risk of dehydration by the name of "Dehydration Risk Appraisal Checklist." In order to verify its usefulness in identifying the risk of dehydration, 2 groups of elderly persons at the OU Geriatrics and long-term care unit of the Azienda USL of Piacenza and the OU complex Geriatric Clinic of the University Hospital of Parma were investigated. Patients in both groups were assessed on admission by the assessment scale MNA (Mini Nutritional Assessment) and by the sheet of quantitative evaluation of the meal consumed. One group was considered as the "control group". Patients belonging to the other group, which was regarded as the "experimental group", in addition to the two above-mentioned instruments, were also assessed by the "Dehydration risk appraisal checklist". In both groups, the presence or absence of four indicators of dehydration measured at the time of and immediately before discharge was then detected. In the presence of each indicator of dehydration one point was awarded for a comprehensive evaluation. The data collected were

Hydrogen-Bond Directed Regioselective Pd-Catalyzed Asymmetric Allylic Alkylation: The Construction of Chiral α-Amino Acids with Vicinal Tertiary and Quaternary Stereocenters.

Science.gov (United States)

Wei, Xuan; Liu, Delong; An, Qianjin; Zhang, Wanbin

2015-12-04

A Pd-catalyzed asymmetric allylic alkylation of azlactones with 4-arylvinyl-1,3-dioxolan-2-ones was developed, providing "branched" chiral α-amino acids with vicinal tertiary and quaternary stereocenters, in high yields and with excellent selectivities. Mechanistic studies revealed that the formation of a hydrogen bond between the Pd-allylic complex and azlactone isomer is responsible for the excellent regioselectivities. This asymmetric alkylation can be carried out on a gram scale without a loss of catalytic efficiency, and the resulting product can be further transformed to a chiral azetidine in two simple steps.

Hydration–dehydration behavior and thermodynamics of MX-80 montmorillonite studied using thermal analysis

Energy Technology Data Exchange (ETDEWEB)

Tajeddine, L. [CNRS-IC2MP-UMR- Hydrasa, 5 Ave Albert, Turpain, (France); Gailhanou, H.; Blanc, P.; Lassin, A.; Gaboreau, S. [BRGM, 3 Av. Claude Guillemin, BP6009, Orléans F-45060 (France); Vieillard, P., E-mail: philippe.vieillard@univ-poitiers.fr [CNRS-IC2MP-UMR- Hydrasa, 5 Ave Albert, Turpain, (France)

2015-03-20

Highlights: • Adsorption–desorption of water on MX-80 is determined from TGA and DTA analysis. • From DTA analysis, three types of water behavior exist at various hydration states. • Surface area of DTA allows to determine the dehydration enthalpy per mole of water. • A maximum enthalpy is 12 kJ/mol for the adsorption and desorption processes. • Enthalpy of formation of water for adsorption and desorption processes are provided. - Abstract: The thermal dehydration of natural bentonite clay MX-80 chosen as a possible future backfill material, was investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The aim of this work is to provide a better understanding of the thermodynamics of the hydration–dehydration process of MX-80. The data obtained from thermogravimetry derivative curves at different relative humidities were used to determine the adsorption–desorption isotherm of MX-80. The total amount of water varies from 0.35 to 5.62 and from 0.78 to 6.12 mol adsorbed H{sub 2}O/mol of clay upon adsorption and desorption, respectively, for a RH between 11 and 91%. Furthermore, the heats released upon adsorption and desorption are not completely similar. Moreover, the analysis of DTA signals obtained at various hydration states provides insights about three types of water behavior in MX-80. Therefore, the surface area of DTA curves was taken into account to determine the dehydration enthalpy per mole of water; the values do not correlate with the amount of adsorbed water in MX-80, and the maximum enthalpy was approximately 12 kJ/mol for the adsorption and desorption studies. The values obtained were combined with the standard enthalpies of the formation of liquid water to obtain the corresponding enthalpy of the formation of water relative to dehydrated MX-80.

Mushroom dehydration in a hybrid-solar dryer

International Nuclear Information System (INIS)

Reyes, Alejandro; Mahn, Andrea; Cubillos, Francisco; Huenulaf, Pedro

2013-01-01

Highlights: ► Mushrooms (Paris variety) were dehydrated in a hybrid solar dryer. ► Effective diffusivity was estimated by the Constant Diffusivity Model. ► Drying kinetics were adjusted by a semi-theoretical and the empirical Page model. ► Temperature, thickness and air recycle significantly affected critical moisture. ► The input of solar energy resulted in 3.5–12.5% electrical energy saving. - Abstract: Mushrooms (Paris variety) were dehydrated in a hybrid solar dryer (HSD) provided with a 3 m 2 solar panel and electric resistances. Mushrooms were cut in 8 mm or 4 mm thickness slices. At the outlet of the tray dryer 80–90% air was recycled and the air temperature was adjusted to the pre-defined levels (50 or 60 °C). At the outlet of the solar panel the air temperature raised between 2 and 20 °C above the ambient temperature, depending mainly of solar radiation level. Temperature, slices thickness and air recycle level had statistically significant effects on critical moisture content (X c ), as well as on the time necessary to reach a moisture content of 0.1 (wb). The color parameters of dehydrated mushroom indicate a notorious darkening, in all runs. Rehydration assays at 35 °C showed that in less than 30 min rehydrated mushrooms reached a moisture content of 0.8 (wb). Effective diffusivity (D eff ) was estimated by the Simplified Constant Diffusivity Model (SCDM), and it ranged between 6E−10 and 40E−10 m 2 /s, with R 2 higher than 0.98, agreeing with literature. The adjustment of experimental drying kinetics with the empirical Page’s model resulted in R 2 higher than 0.997. Finally, the input of solar energy resulted in 3.5–12.5% energy saving. These values could even be improved by increasing the agro-product load in the HSD

Influence of bulky substituents on the regioselective group-transfer reactions of diorganozinc compounds with N,N'-bis(2,6-di-isopropylphenyl)-1,4-diaza-1,3-butadiene

NARCIS (Netherlands)

Koten, G. van; Wissing, E.; Gorp, K. van; Boersma, J.

1994-01-01

Diorganozinc compounds R{2}Zn (R=alkyl or aryl) react with N, N'-bis(2,6-di-isopropylphenyl)-1,4-diaza-1,3-butadiene, (i-Pr{2}Ph)N@?CHCHp@?N(i-Pr{2}Ph) (i-Pr{2}Ph-DAB) to give thermally unstable 1:1 coordination complexes R{2}Zn(i-Pr2Ph-DAB), which subsequently undergo a slow regioselective alkyl or

Dreng med diarré og svær dehydrering havde food protein-induced enterocolitis syndrome

DEFF Research Database (Denmark)

Henriksen, Pernille; Børresen, Malene Landbo; Dahl, Kathrin

2016-01-01

Food protein-induced enterocolitis syndrome (FPIES) is a rare non-IgE mediated condition. Symptoms of acute FPIES include vomiting, diarrhoea and dehydration. Symptoms are often misread as acute abdomen or sepsis. The condition can be fatal. There are no biomarkers for FPIES, and skin prick test...... confronted with the very ill, dehydrated infant....

Use of a hand-held bladder ultrasound scanner in the assessment of dehydration and monitoring response to treatment in a paediatric emergency department.

Science.gov (United States)

Enright, Kevin; Beattie, Tom; Taheri, Sepideh

2010-10-01

Dehydration is a common concern in paediatric emergency care. Limited tools are available to assess reduced urine production, which is commonly cited as a reliable marker of dehydration. To evaluate the utility of a hand-held bladder ultrasound scanner in monitoring urine production in children attending the emergency department with suspected dehydration. A prospective pilot study was undertaken on a convenience sample of patients presenting with suspected dehydration. Serial bladder ultrasound scanning was performed to monitor urine output. Dehydration was assessed clinically using the WHO guide to dehydration assessment. Decisions about treatment and admission were made independently of the urine output measurements obtained using the bladder scanner. 45 children were studied. Using the WHO guide, 33 (73%) had mild dehydration, 8 (18%) had moderate dehydration and 4 (9%) had severe dehydration. There was a significant difference in estimated urine production between those admitted and those discharged (0.9±1.2 ml/kg/h vs 1.8±1.5 ml/kg/h, p=0.01) and between those with mild dehydration versus moderate/severe dehydration (2.3±1.5 ml/kg/h vs 0.6±0.7 ml/kg/h, p=0.0011). Urine output had been significantly reduced in those who had received an intravenous fluid bolus compared with those who had not (0.4±0.46 ml/kg/h vs 1.9±1.6 ml/kg/h, p=0.001). The hand-held bladder scanner is a convenient, non-invasive and objective adjunct in the assessment and management of children attending the emergency department with suspected dehydration.

Science Study Aids 1: Dehydration for Food Preservation.

Science.gov (United States)

Boeschen, John; And Others

This publication is the first of a series of seven supplementary investigative materials for use in secondary science classes providing up-to-date research-related investigations. This unit is structured for grades 9 through 12. It is concerned with the osmatic dehydration of fruits. The guide provides students with information about food…

Exploring the role of genome and structural ions in preventing viral capsid collapse during dehydration

Science.gov (United States)

Martín-González, Natalia; Guérin Darvas, Sofía M.; Durana, Aritz; Marti, Gerardo A.; Guérin, Diego M. A.; de Pablo, Pedro J.

2018-03-01

Even though viruses evolve mainly in liquid milieu, their horizontal transmission routes often include episodes of dry environment. Along their life cycle, some insect viruses, such as viruses from the Dicistroviridae family, withstand dehydrated conditions with presently unknown consequences to their structural stability. Here, we use atomic force microscopy to monitor the structural changes of viral particles of Triatoma virus (TrV) after desiccation. Our results demonstrate that TrV capsids preserve their genome inside, conserving their height after exposure to dehydrating conditions, which is in stark contrast with other viruses that expel their genome when desiccated. Moreover, empty capsids (without genome) resulted in collapsed particles after desiccation. We also explored the role of structural ions in the dehydration process of the virions (capsid containing genome) by chelating the accessible cations from the external solvent milieu. We observed that ion suppression helps to keep the virus height upon desiccation. Our results show that under drying conditions, the genome of TrV prevents the capsid from collapsing during dehydration, while the structural ions are responsible for promoting solvent exchange through the virion wall.

Optimization of the carrot leaf dehydration aiming at the preservation of omega-3 fatty acids

Directory of Open Access Journals (Sweden)

Vanessa Vivian de Almeida

2009-01-01

Full Text Available The carrot leaf dehydration conditions in air circulation oven were optimized through response surface methodology (RSM for minimizing the degradation of polyunsaturated fatty acids, particularly alpha-linolenic (LNA, 18:3n-3. The optimized leaf drying time and temperature were 43 h and 70 ºC, respectively. The fatty acids (FA were investigated using gas chromatography equipped with a flame ionization detector and fused silica capillary column; FA were identified with standards and based on equivalent-chain-length. LNA and other FA were quantified against C21:0 internal standard. After dehydration, the amount of LNA, quantified in mg/100 g dry matter of dehydrated carrot leaves, were 984 mg.

Diastereo- and regioselective addition of thioamide dianions to imines and aziridines: synthesis of N-thioacyl-1,2-diamines and N-thioacyl-1,3-diamines.

Science.gov (United States)

Shibahara, Fumitoshi; Kobayashi, Shun-ichiro; Maruyama, Toshifumi; Murai, Toshiaki

2013-01-02

Addition reactions of thioamide dianions that were derived from N-arylmethyl thioamides to imines and aziridines were carried out. The reactions of imines gave the addition products of N-thioacyl-1,2-diamines in a highly diastereoselective manner in good-to-excellent yields. The diastereomeric purity of these N-thioacyl-1,2-diamines could be enriched by simple recrystallization. The reduction of N-thioacyl-1,2-diamines with LiAlH(4) gave their corresponding 1,2-diamines in moderate-to-good yields with retention of their stereochemistry. The oxidative-desulfurization/cyclization of an N-thioacyl-1,2-diamine in CuCl(2)/O(2) and I(2)/pyridine systems gave the cyclized product in moderate yield and the trans isomer was obtained as the sole product. On the other hand, a similar cyclization reaction with antiformin (aq. NaClO) as an oxidant gave the cis isomer as the major product. The reactions of N-tosylaziridines gave the addition products of N-thioacyl-1,3-diamines with low diastereoselectivity but high regioselectivity and in good-to-excellent yields. The use of AlMe(3) as an additive improved the efficiency and regioselectivity of the reaction. The stereochemistry of the obtained products was determined by X-ray diffraction. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of a simulation evaluation tool for assessing nursing students' clinical judgment in caring for children with dehydration.

Science.gov (United States)

Kim, Shin-Jeong; Kim, Sunghee; Kang, Kyung-Ah; Oh, Jina; Lee, Myung-Nam

2016-02-01

The lack of reliable and valid tools to evaluate learning outcomes during simulations has limited the adoption and progress of simulation-based nursing education. This study had two aims: (a) to develop a simulation evaluation tool (SET(c-dehydration)) to assess students' clinical judgment in caring for children with dehydration based on the Lasater Clinical Judgment Rubric (LCJR) and (b) to examine its reliability and validity. Undergraduate nursing students from two nursing schools in South Korea participated in this study from March 3 through June 10, 2014. The SET(c-dehydration) was developed, and 120 nursing students' clinical judgment was evaluated. Descriptive statistics, Cronbach's alpha, Cohen's kappa coefficient, and confirmatory factor analysis (CFA) were used to analyze the data. A 41-item version of the SET(c-dehydration) with three subscales was developed. Cohen's kappa (measuring inter-observer reliability) of the sessions ranged from .73 to .95, and Cronbach's alpha was .87. The mean total rating of the SET(c-dehydration) by the instructors was 1.92 (±.25), and the mean scores for the four LCJR dimensions of clinical judgment were as follows: noticing (1.74±.27), interpreting (1.85±.43), responding (2.17±.32), and reflecting (1.79±.35). CFA, which was performed to test construct validity, showed that the four dimensions of the SET(c-dehydration) was an appropriate framework. The SET(c-dehydration) provides a means to evaluate clinical judgment in simulation education. Its reliability and validity should be examined further. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of identification methods of irradiated spices and dehydrated vegetables in Brazil

International Nuclear Information System (INIS)

Bernardes, D.M.L.; Del Mastro, N.L.

1998-01-01

Complete text of publication follows. This paper deals with the use of analytical methods to determine whether imported or for export Brazilian spices and dehydrated vegetables were irradiated. Viscosimetry, thermoluminescence (TL) and electron spin resonance (ESR) were used for the identification of some irradiated products: black pepper, white pepper, cinnamon, nutmeg, garlic, cumin, oregano, celery, paprika and coriander. Viscosimetry was performed in suspensions of irradiated spices and dehydrated vegetables which had been gellified by heat. Thermoluminescence (TL) is based on the transference of electrons to an excited state by radiation with emission of light when the electrons are thermally stimulated. The thermoluminescent signal of spices can be explained by the presence of mineral grains adhering on the surface of the samples. Free radicals produced by irradiation of spices were analyzed by electron spin resonance (EPR) signals. The results of this study lead to the conclusion that viscosimetry, thermoluminescence and electron spin resonance are analytical methods that can be use to detect whether spices and dehydrated vegetables were irradiated, specially when a combination of different methods was used

Highly efficient regioselective synthesis, spectroscopic characterizations and DFT calculations of novel hydroxymethylated 1,4-disubstituted-1,2,3-triazole-based sulfonamides

Science.gov (United States)

Taheri, Elmira; Mirjafary, Zohreh; Saeidian, Hamid

2018-04-01

The novel hydroxymethylated 1,4-disubstituted-1,2,3-triazole-based sulfonamides were synthesized in excellent yields and high regioselectivity via a one-pot, two-step, three-component reaction of N-propargylsulfonamides, sodium azide, and epoxide derivatives under green conditions. Green and mild reaction condition, commercially readily available and inexpensive starting materials, wide scope and easy work-up are the key features of the present method. The Li+ and Na+ ion affinities of the model structure have been also investigated by density functional theory (DFT) studies to find the applicability of these products as ligand in coordination chemistry.

Towards the sustainable production of acrolein by glycerol dehydration.

Science.gov (United States)

Katryniok, Benjamin; Paul, Sébastien; Capron, Mickaël; Dumeignil, Franck

2009-01-01

The massive increase in biodiesel production by transesterification of vegatable oils goes hand-in-hand with the availability of a large volume of glycerol, which must be valorized. Glycerol dehydration to acrolein over acid catalysts is one of the most promising ways of valorization, because this compound is an important chemical intermediate used in, for example, the DL-methionine synthesis. In this Minireview, we give a detailed critical view of the state-of-the-art of this dehydration reaction. The processes developed in both the liquid and the gas phases are detailed and the best catalytic results obtained so far are reported as a benchmark for future developments. The advances on the understanding of the reaction mechanism are also discussed and we further focus particularly on the main obstacles for an immediate industrial application of this technology, namely catalyst coking and crude glycerol direct-use issues.

Comparison of bioavailability and pharmacokinetics of diclofenac sodium and diclofenac potassium in normal and dehydrated rabbits.

Science.gov (United States)

Ahmad, Mahmood; Iqbal, Muhammad; Murtaza, Ghulam

2009-01-01

Two different salts of diclofenac, diclofenac sodium and diclofenac potassium, in tablet dosage form were tested for their bioavailability and disposition kinetics in a group of eighteen rabbits in normal and experimentally induced dehydrated conditions with a wash out period of 7 days between both stages of study. Biochemical and physiological parameters were also measured in both normal and dehydrated states. Diclofenac levels in plasma were determined using a validated reversed phase HPLC method. Primary kinetic parameters i.e. AUC(0-infinity), Cmax, Tmax and other disposition kinetics were obtained with non-compartmental procedure. Biochemical parameters i.e. packed cell volume, plasma glucose and total lipid concentration in dehydrated rabbits increased significantly. Plasma concentration of diclofenac sodium and diclofenac potassium decreased significantly in water deprived rabbits. In comparison, diclofenac potassium in normal and dehydrated state of the same group of rabbits showed a significantly increased plasma concentration when compared with diclofenac sodium.

Synthesis of mesoporous SAPO-34 molecular sieves and their applications in dehydration of butanols and ethanol.

Science.gov (United States)

Jun, Jong Won; Jeon, Jaewoo; Kim, Chul-Ung; Jeong, Kwang-Eun; Jeong, Soon-Yong; Jhung, Sung Hwa

2013-04-01

Microporous SAPO-34 molecular sieves were hydrothermally synthesized with microwave irradiation in the presence of tetraethylammonium hydroxide (TEAOH) as a template. SAPO-34 molecular sieves with mesoporosity were also prepared in the presence of carbon black as a hard template. By increasing the content of the carbon black template in the synthesis, the mesopore volume increased. Dehydration of alcohols (butanols and ethanol) was carried out with the synthesized SAPO-34 molecular sieves, and the lifetime of the catalysts for the dehydration reaction increased as the mesoporosity increased. Moreover, the performance of the microporous catalyst synthesized with microwave was better than that of the catalyst obtained with conventional electric heating. The relative performance of the catalytic dehydration may be explained by the mesoporosity and the crystal size. Therefore, it may be concluded that small-sized SAPO-34 molecular sieves with high mesoporosity can be produced efficiently with microwave irradiation in the presence of carbon black template, and the molecular sieves are effective in the stable dehydration of alcohols.

Ethanol dehydration in HZSM-5 studied by density functional theory: evidence for a concerted process.

Science.gov (United States)

Kim, Seonah; Robichaud, David J; Beckham, Gregg T; Paton, Robert S; Nimlos, Mark R

2015-04-16

Dehydration over acidic zeolites is an important reaction class for the upgrading of biomass pyrolysis vapors to hydrocarbon fuels or to precursors for myriad chemical products. Here, we examine the dehydration of ethanol at a Brønsted acid site, T12, found in HZSM-5 using density functional theory (DFT). The geometries of both cluster and mixed quantum mechanics/molecular mechanics (QM:MM) models are prepared from the ZSM-5 crystal structure. Comparisons between these models and different DFT methods are conducted to show similar results among the models and methods used. Inclusion of the full catalyst cavity through a QM:MM approach is found to be important, since activation barriers are computed on average as 7 kcal mol(-1) lower than those obtained with a smaller cluster model. Two different pathways, concerted and stepwise, have been considered when examining dehydration and deprotonation steps. The current study shows that a concerted dehydration process is possible with a lower (4-5 kcal mol(-1)) activation barrier while previous literature studies have focused on a stepwise mechanism. Overall, this work demonstrates that fairly high activation energies (∼50 kcal mol(-1)) are required for ethanol dehydration. A concerted mechanism is favored over a stepwise mechanism because charge separation in the transition state is minimized. QM:MM approaches appear to provide superior results to cluster calculations due to a more accurate representation of charges on framework oxygen atoms.

Not Good, but Not All Bad: Dehydration Effects on Body Fluids, Organ Masses, and Water Flux through the Skin of Rhinella schneideri (Amphibia, Bufonidae).

Science.gov (United States)

Anderson, Rodolfo C O; Bovo, Rafael P; Eismann, Carlos E; Menegario, Amauri A; Andrade, Denis V

Because of their permeable skin, terrestrial amphibians are constantly challenged by the potential risk of dehydration. However, some of the physiological consequences associated with dehydration may affect aspects that are themselves relevant to the regulation of water balance. Accordingly, we examined the effects of graded levels of dehydration on the rates of evaporative water loss and water absorption through the skin in the terrestrial Neotropical toad, Rhinella schneideri. Concomitantly, we monitored the effects of dehydration on the mass of visceral organs; hematocrit and hemoglobin content; plasma osmolality; and plasma concentration of urea, sodium, chloride, and potassium. We found that dehydration caused an increase in the concentration of body fluids, as indicated by virtually all the parameters examined. There was a proportional change in the relative masses of visceral organs, except for the liver and kidneys, which exhibited a decrease in their relative masses greater than the whole-body level of dehydration. Changes-or the preservation-of relative organ masses during dehydration may be explained by organ-specific physiological adjustments in response to the functional stress introduced by the dehydration itself. As dehydration progressed, evaporative water loss diminished and water reabsorption increased. In both cases, the increase in body fluid concentration associated with the dehydration provided the osmotic driver for these changes in water flux. Additionally, dehydration-induced alterations on the cutaneous barrier may also have contributed to the decrease in water flux. Dehydration, therefore, while posing a considerable challenge on the water balance regulation of anurans, paradoxically facilitates water conservation and absorption.

Dehydration accelerates reductions in cerebral blood flow during prolonged exercise in the heat without compromising brain metabolism

DEFF Research Database (Denmark)

Trangmar, Steven J; Chiesa, Scott T; Llodio, Iñaki

2015-01-01

Dehydration hastens the decline in cerebral blood flow (CBF) during incremental exercise, whereas the cerebral metabolic rate for O2 (CMRO2 ) is preserved. It remains unknown whether CMRO2 is also maintained during prolonged exercise in the heat and whether an eventual decline in CBF is coupled...... to fatigue. Two studies were undertaken. In study 1, 10 male cyclists cycled in the heat for ∼2 h with (control) and without fluid replacement (dehydration) while internal and external carotid artery blood flow and core and blood temperature were obtained. Arterial and internal jugular venous blood samples...... were assessed with dehydration to evaluate CMRO2 . In study 2, in 8 male subjects, middle cerebral artery blood velocity was measured during prolonged exercise to exhaustion in both dehydrated and euhydrated states. After a rise at the onset of exercise, internal carotid artery flow declined...

Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges.

Science.gov (United States)

Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

2016-05-01

Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10(-3) S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10(-1) S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front.

Mechanistic insights into aqueous phase propanol dehydration in H-ZSM-5 zeolite

Energy Technology Data Exchange (ETDEWEB)

Mei, Donghai [Pacific Northwest National Laboratory, Physical and Computational Sciences Directorate & Institute for Integrated Catalysis, Richland WA 99352; Lercher, Johannes A. [Pacific Northwest National Laboratory, Physical and Computational Sciences Directorate & Institute for Integrated Catalysis, Richland WA 99352; Dept. of Chemistry and Catalysis Research Institute, TU München, Lichtenbergstrasse 4 Garching 85748 Germany

2016-10-06

Aqueous phase dehydration of 1-propanol over H-ZSM-5 zeolite was investigated using density functional theory (DFT) calculations. The water molecules in the zeolite pores prefer to aggregate via the hydrogen bonding network and be protonated at the Brønsted acidic sites (BAS). Two typical configurations, i.e., dispersed and clustered, of water molecules were identified by ab initio molecular dynamics simulation of the mimicking aqueous phase H-ZSM-5 zeolite unit cell with 20 water molecules per unit cell. DFT calculated Gibbs free energies suggest that the dimeric propanol-propanol, the propanol-water complex, and the trimeric propanol-propanol-water are formed at high propanol concentrations, which provide a kinetically feasible dehydration reaction channel of 1-propanol to propene. However, calculation results also indicate that the propanol dehydration via the unimolecular mechanism becomes kinetically discouraged due to the enhanced stability of the protonated dimeric propanol and the protonated water cluster acting as the BAS site for alcohol dehydration reaction. This work was supported by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. Computing time was granted by the grand challenge of computational catalysis of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL). EMSL is a national scientific user facility located at Pacific Northwest National Laboratory (PNNL) and sponsored by DOE’s Office of Biological and Environmental Research.

Liquid-phase and vapor-phase dehydration of organic/water solutions

Science.gov (United States)

Huang, Yu [Palo Alto, CA; Ly, Jennifer [San Jose, CA; Aldajani, Tiem [San Jose, CA; Baker, Richard W [Palo Alto, CA

2011-08-23

Processes for dehydrating an organic/water solution by pervaporation or vapor separation using fluorinated membranes. The processes are particularly useful for treating mixtures containing light organic components, such as ethanol, isopropanol or acetic acid.

Sequential Dy(OTf)3 -Catalyzed Solvent-Free Per-O-Acetylation and Regioselective Anomeric De-O-Acetylation of Carbohydrates.

Science.gov (United States)

Yan, Yi-Ling; Guo, Jiun-Rung; Liang, Chien-Fu

2017-09-19

Dysprosium(III) trifluoromethanesulfonate-catalyzed per-O-acetylation and regioselective anomeric de-O-acetylation of carbohydrates can be tuned by adjusting the reaction medium. In this study, the per-O-acetylation of unprotected sugars by using a near-stoichiometric amount of acetic anhydride under solvent-free conditions resulted in the exclusive formation of acetylated saccharides as anomeric mixtures, whereas anomeric de-O-acetylation in methanol resulted in a moderate-to-excellent yield. Reactions with various unprotected monosaccharides or disaccharides followed by a semi-one-pot sequential conversion into the corresponding acetylated glycosyl hemiacetal also resulted in high yields. Furthermore, the obtained hemiacetals could be successfully transformed into trichloroimidates after Dy(OTf) 3 -catalyzed glycosylation. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kinetics of Maleic Acid and Aluminum Chloride Catalyzed Dehydration and Degradation of Glucose

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ximing; Hewetson, Barron B.; Mosier, Nathan S.

2015-04-16

We report the positive effect of maleic acid, a dicarboxylic acid, on the selectivity of hexose dehydration to 5-hydroxymethyfurfural (HMF) and subsequent hydrolysis to levulinic and formic acids. We also describe the kinetic analysis of a Lewis acid (AlCl3) alone and in combination with HCl or maleic acid to catalyze the isomerization of glucose to fructose, dehydration of fructose to HMF, hydration of HMF to levulinic and formic acids, and degradation of these compounds to humins. The results show that AlCl3 significantly enhances the rate of glucose conversion to HMF and levulinic acid in the presence of both maleic acid and HCl. In addition, the degradation of HMF to humins, rather than levulinic and formic acids, is reduced by 50% in the presence of maleic acid and AlCl3 compared to HCl combined with AlCl3. The results suggest different reaction mechanisms for the dehydration of glucose and rehydration of HMF between maleic acid and HCl.

NONCHEMICAL DEHYDRATION OF FIXED TISSUE COMBINING MICROWAVES AND VACUUM

NARCIS (Netherlands)

KOK, LP; BOON, ME

A novel histoprocessing method for paraffin and plastic sections is presented in which dehydration of fixed tissue blocks is achieved within 5 minutes by microwaving under vacuum. Exploiting the decrease in boiling temperature under vacuum, we succeed in evaporating liquid molecules in the tissues

Effect of postharvest dehydration on the composition of pinot noir grapes (Vitis vinifera L.) and wine.

Science.gov (United States)

Moreno, Jorge J; Cerpa-Calderón, Fiorella; Cohen, Seth D; Fang, Yu; Qian, Michael; Kennedy, James A

2008-08-15

This study was conducted in order to improve our understanding of how phenolics and aroma compounds change in wine grapes during postharvest dehydration. Pinot noir grapes grown in the Willamette Valley of Oregon were harvested at 22.0 and 24.0°Brix. Grapes harvested at 22.0°Brix were divided into three equal lots with one lot immediately used for wine production, and the remaining two lots placed inside an air tunnel with an air speed of 1.0-1.8ms(-1), 38% relative humidity and a temperature of 22°C. The soluble solids content and weight loss were measured daily and wines were made from grapes when they reached 24.8 and 26.7°Brix. The soluble solids of grapes increased about 1°Brix per day; therefore, on the third and fourth day the berries reached the desired concentration; weight loss was 14 and 16%, respectively. Results from berry phenolic analysis indicated that per berry anthocyanin amount remained unchanged during dehydration. The composition of proanthocyanidins isolated from berries changed during dehydration. Volatile compounds in wines made from dehydrated grapes contained more terpenes and norisoprenoids (β-ionone, β-damascenone) when compared to wine made from the original fruit. Wines made from increasingly dehydrated grapes tended to resemble the composition and flavour profile of wines made from grapes left on the vine (i.e. with extended ripening). The results of this study suggest that postharvest flavour changes consistent with changes during fruit ripening can occur in grapes when harvested early and allowed to dehydrate under controlled conditions prior to fermentation. Copyright © 2008 Elsevier Ltd. All rights reserved.

Tritiated water metabolism during dehydration and rehydration in the camel

International Nuclear Information System (INIS)

Etzion, Z.; Meyerstein, N.; Yagil, R.

1984-01-01

The metabolism of tritiated water in the camel was compared in two 10-day periods, one when water was readily available and the second during dehydration. There was a radically depressed metabolism after 2 days of dehydration. Two other experiments examined the absorption rate of drinking water. In one experiment drinking water was labeled with tritium, and in the second experiment dilution of tritium-labeled blood was examined. In both experiments there was a rapid uptake and dilution of the blood, which continued for 4 h. Following this only slight changes were observed up to 24 h after drinking. The results are in accord with other data showing changes in erythrocyte shape 4 h after rapid rehydration. It is concluded that there is a rapid absorption of water in the rehydrating camel

Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity.

Science.gov (United States)

Georgescu, Vincent P; de Souza Junior, Tacito P; Behrens, Christian; Barros, Marcelo P; Bueno, Carlos Alves; Utter, Alan C; McAnulty, Lisa S; McAnulty, Steven R

2017-07-01

Dehydration is a common event associated with exercise. However, few studies have examined the effects of dehydration on plasma redox status in humans. Eighty-two athletes were recruited and baseline anthropometrics and blood samples were obtained. Athletes then engaged in a dehydration protocol, training until 3% of preweight body mass was lost. Athletes returned to the lab and had postdehydration blood collected. Athletes then consumed an isotonic drink until pre-exercise body weight was reestablished. Blood was then recollected (1 h post full rehydration (PFR)). Samples were centrifuged and the plasma snap frozen in liquid nitrogen and stored at -80 °C. Lipid and protein oxidative stress was determined by measuring F 2 -isoprostanes and protein carbonyls (PC), respectively. Antioxidant capacity was determined by the ferric reducing ability of plasma (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays. Plasma osmolality was determined using an osmometer. Statistical analysis utilized a 1-way ANOVA with posthoc testing. Values are reported as mean ± SD. Plasma osmolality was significantly elevated immediately postdehydration (p ≤ 0.001) but decreased to baseline at PFR. Plasma TEAC increased immediately postdehydration and at PFR (p ≤ 0.001). FRAP increased immediately postdehydration (p ≤ 0.001) and decreased to below baseline at PFR (p ≤ 0.05). Conversely, F 2 -isoprostanes declined significantly from baseline to immediately postdehydration and then significantly rose at PFR (p ≤ 0.001), whereas PC declined at PFR (p ≤ 0.01). This study indicates that dehydration and exercise cause a significant increase in plasma osmolality and antioxidant potential immediately postexercise. We propose dehydration significantly elevates antioxidant concentration which suppresses F 2 -isoprostanes and PC.

Point-of-Admission Serum Electrolyte Profile of Children less than Five Years Old with Dehydration due to Acute Diarrhoea.

Science.gov (United States)

Okposio, Matthias Mariere; Onyiriuka, Alphonsus Ndidi; Abhulimhen-Iyoha, Blessing Imuetiyan

2015-12-01

Fluid, electrolytes and acid base disturbances are responsible for most deaths due to acute diarrhoea. The aim of this study is to describe the point-of-admission serum electrolyte profile of children with dehydration due to acute diarrhoea. In this cross-sectional study, the serum electrolyte levels of 185 children with dehydration due to acute diarrhoea were assessed at the point of admission at the Diarrhoea Treatment and Training Unit of the University of Benin Teaching Hospital. The age of the study population ranged from 29 days to 59 months. Out of a total of 185 subjects, 30 (16.2%), 114 (61.6%), and 41 (22.2%) had severe, moderate and mild dehydration, respectively. In addition, hyponatraemic dehydration was the most common type of dehydration, accounting for 60.5% of cases. Metabolic acidosis and hypokalaemia occurred in 59.5% and 44.3% of cases, respectively. Only the serum bicarbonate level was significantly affected by degree of dehydration (p = 0.001). Age of more than 12 months and presence of vomiting were significantly associated with hyponatraemia (p = 0.005 & p = 0.02), while age of less than or equal 12 months and absence of vomiting were associated with metabolic acidosis (p = 0.04 & p = 0.03). The degree of dehydration appears to be a good predictor of the occurrence of metabolic acidosis while age is a risk factor for hyponatraemia and metabolic acidosis.

Reduction of air pollution with new dehydration concepts

International Nuclear Information System (INIS)

Khoi, V.V.

1991-01-01

The conference paper deals with the new dehydration concepts being designed for preventing hydrate formation during the transport of gas for a group of fields being under development in the North Sea. The development comprises a central production platform consisting of a gas treatment system using triethylene and/or diethylene glycol in the process. 4 figs., 3 tabs

Effect of Si/Al2 Ratio on 2-butanol Dehydration over HY Zeolite Catalysts

International Nuclear Information System (INIS)

Jung, Euna; Choi, Hyeonhee; Jeon, Jong-Ki

2015-01-01

Synthesis of butenes through dehydration of 2-butanol was investigated over HY zeolite catalysts. 2-Butanol dehydration reaction was carried out in a fixed bed catalytic reactor. 2-Butanol conversion was increased with increase of Si/Al 2 ratio of HY zeolite catalysts, which can be ascribed to increase of acid strength with increase of Si/Al 2 ratio. Selectivities to 1-butene, trans-2-butene, and cis-2-butene were not greatly influenced by the change of the Si/Al 2 ratio of HY zeolite. As a result, it was advantageous to use a HY zeolite catalyst with 60 Si/Al 2 ratio for maximizing the yield of 1-butene in the dehydration of 2-butanol. The optimal reaction temperature for maximizing the yield of 1-butene was 250 .deg. C over HY (60) catalyst

Effect of irradiation on detection of bacteria in dehydrated vegetables with ATP bioluminescence assay

International Nuclear Information System (INIS)

Xiao Huan; Luo Shishi; Wang Zegang; Feng Min; Zhu Jiating; Chen Xiulan; Zhai Jianqing

2011-01-01

ATP bioluminescence intensity of 4 kinds of irradiated dehydrated vegetables was inconsistent with the bacteria number, the reasons were investigated in this paper. Results showed that irradiation had little effect on background luminescence, and there was no effect on luciferase-luminous system. When irradiation killed the bacteria, the ATPase activity also decreased. As a result, the ATP content in bacteria didn't decreased with the killed of bacteria, which contributed to the increase of free ATP in ATP extract and finally led to the disagreement between the bioluminescence intensity and the actual number of bacteria. When the free ATP in the dehydrated vegetable was removed, the bioluminescence intensity of ATP extract was consistent with the actual number of bacteria in irradiated dehydrated vegetable and ATP bioluminescence technology could be used in bacteria detection of irradiated samples. (authors)

Clinical symptoms, signs and tests for identification of impending and current water-loss dehydration in older people.

Science.gov (United States)

Hooper, Lee; Abdelhamid, Asmaa; Attreed, Natalie J; Campbell, Wayne W; Channell, Adam M; Chassagne, Philippe; Culp, Kennith R; Fletcher, Stephen J; Fortes, Matthew B; Fuller, Nigel; Gaspar, Phyllis M; Gilbert, Daniel J; Heathcote, Adam C; Kafri, Mohannad W; Kajii, Fumiko; Lindner, Gregor; Mack, Gary W; Mentes, Janet C; Merlani, Paolo; Needham, Rowan A; Olde Rikkert, Marcel G M; Perren, Andreas; Powers, James; Ranson, Sheila C; Ritz, Patrick; Rowat, Anne M; Sjöstrand, Fredrik; Smith, Alexandra C; Stookey, Jodi J D; Stotts, Nancy A; Thomas, David R; Vivanti, Angela; Wakefield, Bonnie J; Waldréus, Nana; Walsh, Neil P; Ward, Sean; Potter, John F; Hunter, Paul

2015-04-30

There is evidence that water-loss dehydration is common in older people and associated with many causes of morbidity and mortality. However, it is unclear what clinical symptoms, signs and tests may be used to identify early dehydration in older people, so that support can be mobilised to improve hydration before health and well-being are compromised. To determine the diagnostic accuracy of state (one time), minimally invasive clinical symptoms, signs and tests to be used as screening tests for detecting water-loss dehydration in older people by systematically reviewing studies that have measured a reference standard and at least one index test in people aged 65 years and over. Water-loss dehydration was defined primarily as including everyone with either impending or current water-loss dehydration (including all those with serum osmolality ≥ 295 mOsm/kg as being dehydrated). Structured search strategies were developed for MEDLINE (OvidSP), EMBASE (OvidSP), CINAHL, LILACS, DARE and HTA databases (The Cochrane Library), and the International Clinical Trials Registry Platform (ICTRP). Reference lists of included studies and identified relevant reviews were checked. Authors of included studies were contacted for details of further studies. Titles and abstracts were scanned and all potentially relevant studies obtained in full text. Inclusion of full text studies was assessed independently in duplicate, and disagreements resolved by a third author. We wrote to authors of all studies that appeared to have collected data on at least one reference standard and at least one index test, and in at least 10 people aged ≥ 65 years, even where no comparative analysis has been published, requesting original dataset so we could create 2 x 2 tables. Diagnostic accuracy of each test was assessed against the best available reference standard for water-loss dehydration (serum or plasma osmolality cut-off ≥ 295 mOsm/kg, serum osmolarity or weight change) within each study. For

Layer by Layer Composite Membranes of Alginate-Chitosan Crosslinked by Glutaraldehyde in Pervaporation Dehydration of Ethanol

Directory of Open Access Journals (Sweden)

Nur Rokhati

2016-08-01

Full Text Available Hydrophilicity of membrane causing only water can pass through membrane. Pervaporation process using organophilic membrane has been offered as alternative for ethanol dehydration. This paper investigate pervaporation based biopolymer composite membrane from alginate-chitosan using layer by layer method prepared by glutaraldehyde as crosslinking agent and polyethersulfone (PES as supported membrane. Characterization of crosslinked of composite membrane by FTIR helped in identification of sites for interaction between layers of membrane and support layer (PES. The SEM showed a multilayer structure and a distinct interface between the chitosan layer, the sodium alginate layer and the support layer. The coating sequence of membranes had an obvious influence on the pervaporation dehydration performance of membranes. For the dehydration of 95 wt% ethanol-water mixtures, a good performance of PES-chitosan-alginate-chitosan (PES/Chi/Alg/Chi composite membrane was found in the pervaporation dehydration of ethanol. Article History: Received April 12nd , 2016; Received in revised form June 25th , 2016; Accepted July 1st , 2016; Available online How to Cite This Article: Rokhati, N., Istirokhatun, T. and Samsudin, A.M. (2016 Layer by Layer Composite Membranes of Alginate-Chitosan Crosslinked by Glutaraldehyde in Pervaporation Dehydration of Ethanol. Int. Journal of Renewable Energy Development, 5(2, 101-106. http://dx.doi.org/10.14710/ijred.5.2.101-106 

Dehydration of detomidine hydrochloride monohydrate.

Science.gov (United States)

Veldre, K; Actiņš, A; Jaunbergs, J

2011-10-09

The thermodynamic stability of detomidine hydrochloride monohydrate has been evaluated on the basis of phase transition kinetics in solid state. A method free of empirical models was used for the treatment of kinetic data, and compared to several known solid state kinetic data processing methods. Phase transitions were monitored by powder X-ray diffraction (PXRD) and thermal analysis. Full PXRD profiles were used for determining the phase content instead of single reflex intensity measurements, in order to minimize the influence of particle texture. We compared the applicability of isothermal and nonisothermal methods to our investigation of detomidine hydrochlorine monohydrate dehydration. Copyright © 2011 Elsevier B.V. All rights reserved.

Partial dehydration and cryopreservation of Citrus seeds.

Science.gov (United States)

Graiver, Natalia; Califano, Alicia; Zaritzky, Noemí

2011-11-01

Three categories of seed storage behavior are generally recognized among plant species: orthodox, intermediate and recalcitrant. Intermediate seeds cannot be stored in liquid nitrogen (LN) without a previous partial dehydration process. The water content (WC) of the seeds at the moment of immersion in LN must be regarded as the most critical factor in cryopreservation. The purpose of this study was to investigate the basis of the optimal hydration status for cryopreservation of Citrus seeds: C. sinensis (sweet orange), C. paradisi (grapefruit), C. reticulata (mandarin) in LN. To study the tolerance to dehydration and LN exposure, seeds were desiccated by equilibration at relative humidities between 11 and 95%. Sorption isotherms were determined and modeled; lipid content of the seeds was measured. Seed desiccation sensitivity was quantified by the quantal response model. Differential scanning calorimetry (DSC) thermograms were determined on cotyledon tissue at different moisture contents to measure ice melting enthalpies and unfrozen WC. Samples of total seed lipid extract were also analyzed by DSC to identify lipid transitions in the thermograms. The limit of hydration for LN Citrus seeds treatment corresponded to the unfrozen WC in the tissue, confirming that seed survival strictly depended on avoidance of intracellular ice formation. Copyright © 2011 Society of Chemical Industry.

Neutron activation analysis of trace metallic elements eluted from molecular sieves in the dehydration process of safflower oil

Energy Technology Data Exchange (ETDEWEB)

Takasago, Masahisa; Kobayashi, Koichi; Taru, Yasunori; Takaoka, Kyo (Musashi Inst. of Tech., Tokyo (Japan))

1992-11-01

Dissolved water in safflower oil affects the autoxidation of this oil significantly. Molecular sieves were used to remove the dissolved water from the oil. This method is much simpler than that of distillation, and dissolved water can be removed to the same extent as that by distillation. But, due to the elution of many kinds of trace metallic elements in the oil dehydrated with molecular sieves, these elements were analyzed by neutron activation analysis. For a data comparison trace amounts of metallic elements in the oil dehydrated by distillation were also analyzed. Since the intensity of the [gamma] ray-photoelectric peak of nuclide [sup 28]Al was largest among the detected elements, this element was analyzed quantitatively and the other elements qualitatively. In safflower oil dehydrated with molecular sieves, 14 kinds of the elements (I, Br, Al, Mg, Si, V, Cl, Nd, Ta, Cr, Sb, Cs, Co, Na) were detected. Also, I, Br, Cl, Cr, Ta, Sb, and Al elements were detected in the oil dehydrated by distillation. The intensity of the photoelectric peak of nuclide except [sup 28]Al was essentially the same as that in the oil dehydrated by distillation, but the intensity of [sup 28]Al in the oil with molecular sieves was about 28 times stronger than that in distillation oil. In the molecular sieves, 19 impure elements in addition to the original constituents (Na, K, Al, si, O) were detected. It was Al, Na, Si, Nd, Cs, and Co along with impure elements may possibly have been eluted in the oil. Al element in safflower oil dehydrated with molecular sieves was analyzed quantitatively. 0.91 ppm of Al was detected in safflower oil. The eluted amount of Al in safflower oil dehydrated by distillation was 0.032 ppm. A larger amount of Al element was thus eluted into the oil dehydrated with molecular sieves than by distillation. (author).

Long-Term Neurodevelopmental Outcome of Neonates with Hypernatremic Dehydration.

Science.gov (United States)

Boskabadi, Hassan; Akhondian, Javad; Afarideh, Maliheh; Maamouri, Gholamali; Bagheri, Sepideh; Parizadeh, Seyyed Mostafa; Mobarhan, Majid Ghayour; Mohammadi, Shabnam; Frens, Gordon A A

2017-04-01

Neonatal hypernatremic dehydration (NHD) is a dangerous condition that can lead to severe weight loss, renal impairment, and central nervous system complications. We aimed to evaluate the consequences of NHD in infants in their second year of life. This was a prospective case-control study in Ghaem hospital, Mashhad, Iran. Sixty-five healthy breastfed neonates (serum sodium concentration dehydration has an adverse effect on child development especially in the first year of life, their prevalence decreases with advanced age. Growth problems are also present during their first year of life. The major signs and symptoms of infants with poor prognosis on admission were poor feeding (8 infants, 61.5%), seizure (3 infants, 23.1%), hyperthermia (1 infant, 7.7%), and lethargy (1 infant, 7.7%). NHD affects growth parameters and developmental milestones of children. Occasionally the child's weight gain was normalized by the end of first year of life; although developmental delay continued, its severity was reduced, with age.

Dehydration of sodium carbonate monohydrate with indirect microwave heating

International Nuclear Information System (INIS)

Seyrankaya, Abdullah; Ozalp, Baris

2006-01-01

In this study, dehydration of sodium carbonate monohydrate (Na 2 CO 3 .H 2 O) (SCM) in microwave (MW) field with silicon carbide (SiC) as an indirect heating medium was investigated. SCM samples containing up to 3% free moisture were placed in the microwave oven. The heating experiments showed that SCM is a poor microwave energy absorber for up to 6 min of irradiation at an 800 W of microwave power. The heat for SCM calcination is provided by SiC which absorbs microwave. The monohydrate is then converted to anhydrous sodium carbonate on the SiC plate by calcining, i.e. by removing the crystal water through heating of the monohydrate temperatures of over 120 deg. C. The calcination results in a solid phase recrystallization of the monohydrate into anhydrate. In the microwave irradiation process, dehydration of SCM in terms of indirect heating can be accelerated by increasing the microwave field power

Conceptual design of heterogeneous azeotropic distillation process for ethanol dehydration using 1-butanol as entrainer

Directory of Open Access Journals (Sweden)

Paritta Prayoonyong

2014-12-01

Full Text Available The synthesis of a heterogeneous azeotropic distillation process for ethanol dehydration using 1-butanol as entrainer is presented. The residue curve map of the ethanol/water/1-butanol mixture is computationally generated using non-random twoliquid thermodynamic model. It is found that 1-butanol leads to a residue curve map topological structure different from that generated by typical entrainers used in ethanol dehydration. Synthesised by residue curve map analysis, the distillation flowsheet for ethanol dehydration by 1-butanol comprises a double-feed column integrated with an overhead decanter and a simple column. The double-feed column is used to recover water as the top product, whereas the simple column is used for recovering ethanol and 1-butanol. The separation feasibility and the economically near-optimal designs of distillation columns in the flowsheet are evaluated and identified by using the boundary value design method. The distillation flowsheet using 1-butanol is compared with the conventional process using benzene as entrainer. Based on their total annualised costs, the ethanol dehydration process using 1-butanol is less economically attractive than the process using benzene. However, 1-butanol is less toxic than benzene.

Theoretical Considerations Governing the Dehydration of Fuels by Gas Blowing

National Research Council Canada - National Science Library

Krynitsky, John A

1957-01-01

.... A number of solutions applicable to the dehydration of JP-5 fuel under a variety of operating conditions are included to demonstrate the relative importance of the above parameters and to illustrate the type of performance possible.

Dehydration of ammonium polyuranate gel microspheres

International Nuclear Information System (INIS)

Benadik, A.; Klimova, A.; Bohuslav, V.; Padevet, A.

1976-01-01

The dehydration was studied (i) in a controlled atmosphere in a horizontal tube furnace, (ii) in the air at a temperature of 220 degC, (iii) in azeotropic distillation, (iv) by the effect of vapours of an organic solvent immiscible with water. Methods (iii) and (iv) have proved to be the most favourable because in their application the differences were minimal in the partial pressures of volatile components of the gaseous phase and on the surface of particles as well as temperature gradients along the cross sections. (M.K.)

Oxidative polycondensation of benzimidazole using NaOCl: Synthesis, characterization, optical, thermal and electrical properties of polybenzimidazoles

Science.gov (United States)

Anand, Siddeswaran; Muthusamy, Athianna; Dineshkumar, Sengottuvelu; Chandrasekaran, J.

2017-11-01

A series of polybenzimidazole polymers, poly-2-(1H-benzo[d] imidazole-2-yl) phenol (PBIP2), poly-3-(1H-benzo[d] imidazole-2-yl) phenol (PBIP3) and poly-4-(1H-benzo[d] imidazole-2-yl) phenol (PBIP4) were synthesized by oxidative polycondensation of benzimidazole monomers 2-(1H-benzo [d] imidazole-2-yl) phenol (BIP2), 3-(1H-benzo [d] imidazole-2-yl) phenol (BIP3) and 4-(1H-benzo [d] imidazole-2-yl) phenol (BIP4). The structure of benzimidazoles monomers and polybenzimidazoles (PBI) were confirmed by various spectroscopic techniques. The quantum theoretical calculations of band gap energy values of monomers were done with DFT and are compared with its optical band gap energy values. Fluorescence spectra of these compounds showed maximum emission in blue region. The electrical conductivity of PBIs was measured by four-point probe technique and showed good electrical response on iodine doping and conductivity increases with increase iodine doping time. The differences in conductivities among the three PBIs are in accordance with the charge density on imidazole nitrogens calculated by Huckel method. The high carbines residue (∼40%) at 500 °C in thermo gravimetric analysis shows that the PBIs are having reasonably good thermal stability. Polymers have recorded high dielectric constant at low applied frequency of 50 Hz at 393 K. The I-V characteristics of polybenzimidazoles p-n diodes showed rectifying nature with a typical forward to reverse current in the range -4 to 4 V. The high n values are caused by non homogeneities and effect of series resistance.

Conceptual design of heterogeneous azeotropic distillation process for ethanol dehydration using 1-butanol as entrainer

OpenAIRE

Paritta Prayoonyong

2014-01-01

The synthesis of a heterogeneous azeotropic distillation process for ethanol dehydration using 1-butanol as entrainer is presented. The residue curve map of the ethanol/water/1-butanol mixture is computationally generated using non-random twoliquid thermodynamic model. It is found that 1-butanol leads to a residue curve map topological structure different from that generated by typical entrainers used in ethanol dehydration. Synthesis...

Comparing the Accuracy of the Three Dehydration Scales in Children with Acute Diarrhea in a Developing Country of Kosovo

OpenAIRE

Hoxha, Teuta; Xhelili, Luan; Azemi, Mehmedali; Avdiu, Muharrem; Ismaili-Jaha, Vlora; Efendija-Beqa, Urata; Grajcevci-Uka, Violeta

2015-01-01

Background. Although diarrhea is a preventable disease, it remains the second leading cause of death (after pneumonia) among children aged under five years worldwide. The World Health Organization (WHO) scale, the Gorelick scale, and the Clinical Dehydration Scale (CDS) were created to estimate dehydration status using clinical signs. The purpose of this study is to determine whether these clinical scales can accurately assess dehydration status of children in a developing country of Kosovo. ...

Svær dehydrering hos nyfødt efter ambulant fødsel

DEFF Research Database (Denmark)

Thøstesen, Lisbeth Marianne; Fenger-Grøn, Jesper

2011-01-01

A nine day-old girl was hospitalised because of breast-feeding problems and life-threatening hypernatremic dehydration; weight loss was 30% of birth weight and s-Na 187 mmol/l. The question is raised whether there could be an association to the current changes in the perinatal health care...... in Denmark. The case emphasizes the necessity of a sufficient safety net beneath the newborn children in order to minimise the risk of breast-feeding problems and re-hospitalizing. Neonatal problems such as marked weight loss, dehydration, hypernatremia and marked jaundice are potentially preventable....

Studies on Osmo-air dehydration of different Indian apricot (Prunus armeniaca L.) cultivars

OpenAIRE

Raj, Dev; Sharma, P. C.; Sharera, Sanjay K.

2014-01-01

Suitability of seven cultivars of apricot viz. New Castle, Kaisha, Royal, Suffaida, Nari, Kullu (Local) and Chulli (wild apricot) was evaluated for dehydration. Osmotic dehydration of fruits consisting of dipping prepared fruits in 70° Brix sucrose syrup containing 2,000 ppm potassium metabisulphite (KMS) for 24 h followed by cabinet air drying (55 °C) to desired moisture (20 ± 0.5 %) gave better dried product with good colour and appeal. Dried whole or halved fruits after removal of stones w...