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Sample records for dehydration

  1. Dehydration

    MedlinePlus

    ... to be a little more careful. 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 ...

  2. Onion dehydration

    SciTech Connect

    Lund, J.W.; Lienau, P.J.

    1994-07-01

    This article describes the onion dehydration process as generally practiced in the United States. The actual processing steps from harvest to final product, and geothermal applications for power production and energy requirements in the dehydration industry are discussed. A design of a dehydrator converted to geothermal energy usage is included.

  3. Onion dehydration

    SciTech Connect

    Lund, J.W.

    1995-12-31

    Onion dehydration consists of a continuous operation, belt conveyor using fairly low-temperature hot air from 38-104{degrees}C (100 to 200{degrees}F). Typical processing plants will handle 4500 kg (10,000 pounds) of raw product per hour (single line), reducing the moisture from around 83 % to 4 % (680 to 820 kg - 1,500 to 1,800 pounds finished product). An example of a geothermal processing plant is Integrate Ingredients at Empire, Nevada, in the San Emidio Desert. A total of 6.3 million kg (14 million pounds) of dry product are produced annually: 60% onion and 40% garlic. A 130{degrees}C (266{degrees}F) well provide the necessary heat for the plant.

  4. Evaporation dehydrator

    SciTech Connect

    Bland, L.

    1985-08-06

    A method and apparatus for the treatment of oilfield heavy oil emulsions is provided. The method utilizes, in combination, the steps of evaporation, vapor/liquid separation, and solids settling to dehydrate, degassify and remove solids from the heavy oil emulsion and produce oil having less than 0.5% by volume basic solids and water. The apparatus comprises an insulated, horizontal, cylindrical vessel. Mounted in the upper end of the vessel chamber is an inclined, tubular member having a closed upper end and an open lower end. At its closed end, the member forms a receiving chamber. A mechanical foam breaker extends transversely across the interior of the tubular member, downstream of the chamber. A stack of angularly inclined, heated trays, arranged in zigzag fashion, are positioned beneath the tubular member, to provide an elongate flowpath. The lower end of the tubular member is positioned to feed onto the upper end of the first tray. The flowpath formed by the stack of trays terminates at a level above the bottom of the vessel, so that a quiescent settling sump is provided by the base of the vessel. The vessel includes a feed inlet opening into the receiving chamber, a vapor outlet leading from the top of said vessel, and liquid and solids outlets leading from the sump. A stream of pre-heated heavy oil emulsion is fed to the receiving chamber, wherein part of the contained water in the vapor form breaks out. The foaming stream is contained by the tubular member and is substantially disintegrated by the foam breaker. The stream then issues onto the upper end of the stack of trays and is heated as it passes as a shallow, broad layer over the trays, to gradually evaporate the remaining water from the emulsion and solids. The dehydrated solids are settled out in the sump, leaving oil containing less than 0.5% basic solids and water.

  5. First Aid: Dehydration

    MedlinePlus

    ... Aid: Heat Illness Sun Safety Dehydration Diarrhea Vomiting Word! Dehydration What's the Big Sweat About Dehydration? How to Be Safe When You're in the Sun What's Sweat? Dehydration Is It Important to Drink a Lot of Water? Contact Us Print Resources Send to a Friend ...

  6. Thirst, Drinking Behavior, And Dehydration

    NASA Technical Reports Server (NTRS)

    Greenleaf, John

    1996-01-01

    Report describes review of physiological mechanisms of involuntary dehydration. Researchers considered cellular dehydration and effects of sodium on thirst, as well as extracellular dehydration and restoration of vascular volume, effects of renin on thirst, and effects of heat.

  7. Dehydration (For Teens)

    MedlinePlus

    ... En Español Making a Change – Your Personal Plan Hot Topics Am I in a Healthy Relationship? Who ... from lots of physical activity, especially on a hot day. Even mild dehydration can affect an athlete's ...

  8. Dehydration (For Parents)

    MedlinePlus

    ... Sun "Stomach Flu" A Kid's Guide to Fever Word! Gastroenteritis Food Poisoning What's Sweat? Dehydration Is It Important to Drink a Lot of Water? What's a Healthy Alternative to Water? Gastrointestinal Infections ...

  9. Electrolyte Concentrates Treat Dehydration

    NASA Technical Reports Server (NTRS)

    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.

  10. Cognitive performance and dehydration.

    PubMed

    Adan, Ana

    2012-04-01

    No matter how mild, dehydration is not a desirable condition because there is an imbalance in the homeostatic function of the internal environment. This can adversely affect cognitive performance, not only in groups more vulnerable to dehydration, such as children and the elderly, but also in young adults. However, few studies have examined the impact of mild or moderate dehydration on cognitive performance. This paper reviews the principal findings from studies published to date examining cognitive skills. Being dehydrated by just 2% impairs performance in tasks that require attention, psychomotor, and immediate memory skills, as well as assessment of the subjective state. In contrast, the performance of long-term and working memory tasks and executive functions is more preserved, especially if the cause of dehydration is moderate physical exercise. The lack of consistency in the evidence published to date is largely due to the different methodology applied, and an attempt should be made to standardize methods for future studies. These differences relate to the assessment of cognitive performance, the method used to cause dehydration, and the characteristics of the participants.

  11. Fruits and vegetables dehydration

    NASA Astrophysics Data System (ADS)

    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.

  12. Dehydration in the Older Adult.

    PubMed

    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.].

  13. Onion dehydration: a review.

    PubMed

    Mitra, Jayeeta; Shrivastava, S L; Rao, P S

    2012-06-01

    Onion (Allium cepa), a very commonly used vegetable, ranks third in the world production of major vegetables. Apart from imparting a delicious taste and flavour due to its pungency in many culinary preparations, it serves several medicinal purposes also. Processing and preservation of onion by suitable means is a major thrust area since a long time. The various kinds of treatments followed for dehydration of onion such as convective air drying, solar drying, fluidized bed drying, vacuum microwave drying, infrared drying and osmotic drying are reviewed here. These techniques are mainly used for preservation and value addition of onion. Several researchers have tried for decades to model the drying kinetics and quality parameters, which are also compiled here briefly.

  14. 7 CFR 989.12 - Dehydrator.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... CALIFORNIA Order Regulating Handling Definitions § 989.12 Dehydrator. Dehydrator means any person who produces raisins by dehydrating grapes by artificial means....

  15. [Dehydration due to "mouth broken"].

    PubMed

    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.

  16. Physiologic basis for understanding quantitative dehydration assessment.

    PubMed

    Cheuvront, Samuel N; Kenefick, Robert W; Charkoudian, Nisha; Sawka, Michael N

    2013-03-01

    Dehydration (body water deficit) is a physiologic state that can have profound implications for human health and performance. Unfortunately, dehydration can be difficult to assess, and there is no single, universal gold standard for decision making. In this article, we review the physiologic basis for understanding quantitative dehydration assessment. We highlight how phenomenologic interpretations of dehydration depend critically on the type (dehydration compared with volume depletion) and magnitude (moderate compared with severe) of dehydration, which in turn influence the osmotic (plasma osmolality) and blood volume-dependent compensatory thresholds for antidiuretic and thirst responses. In particular, we review new findings regarding the biological variation in osmotic responses to dehydration and discuss how this variation can help provide a quantitative and clinically relevant link between the physiology and phenomenology of dehydration. Practical measures with empirical thresholds are provided as a starting point for improving the practice of dehydration assessment.

  17. Dehydration kinetics of shocked serpentine

    NASA Technical Reports Server (NTRS)

    Tyburczy, James A.; Ahrens, Thomas J.

    1988-01-01

    Experimental rates of dehydration of shocked and unshocked serpentine were determined using a differential scanning calorimetric technique. Dehydration rates in shocked serpentine are enhanced by orders of magnitude over corresponding rates in unshocked material, even though the impact experiments were carried out under conditions that inhibited direct impact-induced devolatilization. Extrapolation to temperatures of the Martian surface indicates that dehydration of shocked material would occur 20 to 30 orders of magnitude more rapidly than for unshocked serpentine. The results indicate that impacted planetary surfaces and associated atmospheres would reach chemical equilibrium much more quickly than calculations based on unshocked material would indicate, even during the earliest, coldest stages of accretion. Furthermore, it is suggested that chemical weathering of shocked planetary surfaces by solid-gas reactions would be sufficiently rapid that true equilibrium mineral assemblages should form.

  18. Dehydration: physiology, assessment, and performance effects.

    PubMed

    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).

  19. [Study of erythrocyte dehydration using spin labels].

    PubMed

    Moiseev, V A; Mezhidov, S Kh; Nardid, O A

    1989-01-01

    Possibility of studying erythrocyte dehydration by ESR-spin probe is substantiated. Dehydration of erythrocytes in relation to osmolarity of sodium chloride solutions is investigated. The results are shown to agree with the data obtained by radioisotope method.

  20. Experimental Deformation of Dehydrating Antigorite: Challenging Models of Dehydration Embrittlement

    NASA Astrophysics Data System (ADS)

    Hirth, Greg; Chernak, Linda

    2010-05-01

    To test the hypothesis that intermediate depth earthquakes in subduction zones are caused by the dehydration of hydrous phases, we conducted temperature-ramping experiments on antigorite serpentinite. Cold-pressed powdered samples of antigorite were deformed to a high differential stress at 400°C and 1.0 GPa, within the antigorite stability field, where we have shown that deformation localizes. Temperature was then increased at different rates, 1800°C/hr and 180°C/hr, to cross the reaction boundary while the sample continued to deform; samples were deformed at strain rates of 10-4 s-1, 10-5 s-1 and 10-6 s-1. Two additional experiments were conducted in a similar manner at 300°C, 1.5 GPa and 10-5 s-1 but samples remained 'statically' at high stress during the temperature increase. Our results show that although the decrease in stress during temperature ramping is large, stress relaxes stably, even after dehydration. We find that the slopes of the unloading curves are approximately the same for constant values of the ratio (strain rate/ramp rate) and that the unloading slope is greater for higher values of this ratio. In addition, we find that the unloading curves with the greatest slopes are similar to the apparatus compliance, suggesting that we are generating 'slow earthquakes' in our experiments over the course 5 to 10s of minutes. A strain rate stepping experiment indicates that antigorite has velocity strengthening behavior at 700°C and 1.5 GPa suggesting that as soon as an instability develops in the antigorite, the material strengthens sufficiently to not go unstable. Our results thus suggest that antigorite dehydration does not result in 'dehydration embrittlement' but that it may promote slow earthquakes. We have also conducted a preliminary experiment to study the role of effective pressure on deformation behavior after dehydration. A cold-pressed powdered sample of antigorite with a small core of coarse-grained olivine at one end was deformed at 700

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

    PubMed

    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.

  2. METHOD OF DEHYDRATING URANIUM TETRAFLUORIDE

    DOEpatents

    Davis, J.O.; Fogel, C.C.; Palmer, W.E.

    1962-12-18

    Drying and dehydration of aqueous-precipitated uranium tetrafluoride are described. The UF/sub 4/ which normally contains 3 to 4% water, is dispersed into the reaction zone of an operating reactor wherein uranium hexafluoride is being reduced to UF/sub 4/ with hydrogen. The water-containing UF/sub 4/ is dried and blended with the UF/sub 4/ produced in the reactor without interfering with the reduction reaction. (AEC)

  3. Dehydration

    MedlinePlus

    ... too much, for example, from exercising in hot weather Fever Vomiting or diarrhea Urinating too much (uncontrolled ... when you are well. Drink more when the weather is hot or you are exercising. If anyone ...

  4. Detecting dehydration in older people: useful tests.

    PubMed

    Hooper, Lee; Bunn, Diane

    Dehydration is common in older people, leading to longer hospital stays and increased disability and mortality. Health professionals can diagnose water-loss dehydration by taking a blood sample and measuring serum osmolality, but a less-invasive test would be useful. Evidence that tests, clinical signs or questions tested to date are useful when screening for dehydration in older people is limited. This article looks at known risk factors, signs and test for dehydration, and outlines evidence on how useful they have proven to be. Part 2 describes how a care home has used a multicomponent strategy to improve hydration.

  5. A dehydration mechanism for the stratosphere

    NASA Technical Reports Server (NTRS)

    Danielsen, E. F.

    1982-01-01

    Although mean circulations are generally credited with dehydration of the earth's stratosphere, convective instability in the tropics converts mean circulations to small residuals of local convective circulations. The effects of large cumulonimbus which penetrate the stratosphere and form huge anvils in the lower stratosphere are discussed with respect to hydration and dehydration of the stratosphere. Radiative heating at anvil base combined with cooling at anvil top drives a dehydration engine considered essential to explain the dry stratosphere. Seasonal and longitudinal variations in dehydration potentials are examined with maximum potential attributed to Micronesian area during winter and early spring.

  6. Spectral effects of dehydration on phyllosilicates

    NASA Technical Reports Server (NTRS)

    Bruckenthal, E. A.; Singer, R. B.

    1987-01-01

    Six phyllosilicates were progressively dehydrated under controlled conditions in an effort to study the spectral effects of their dehydration. The spectra obtained at each level of hydration provide information that may be used in future spectroscopic observations of the planets, as well as a data set which compliments the existing body of terrestrial soil knowledge.

  7. 7 CFR 929.11 - To can, freeze, or dehydrate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE CRANBERRIES GROWN IN STATES OF... dehydrate. To can, freeze, or dehydrate means to convert cranberries into canned, frozen, or dehydrated cranberries or other cranberry products by any commercial process....

  8. 7 CFR 929.11 - To can, freeze, or dehydrate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE CRANBERRIES GROWN IN STATES OF... dehydrate. To can, freeze, or dehydrate means to convert cranberries into canned, frozen, or dehydrated cranberries or other cranberry products by any commercial process....

  9. 7 CFR 929.11 - To can, freeze, or dehydrate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE CRANBERRIES GROWN IN STATES OF... dehydrate. To can, freeze, or dehydrate means to convert cranberries into canned, frozen, or dehydrated cranberries or other cranberry products by any commercial process....

  10. 7 CFR 929.11 - To can, freeze, or dehydrate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE CRANBERRIES GROWN IN STATES OF... dehydrate. To can, freeze, or dehydrate means to convert cranberries into canned, frozen, or dehydrated cranberries or other cranberry products by any commercial process....

  11. 7 CFR 929.11 - To can, freeze, or dehydrate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE CRANBERRIES GROWN IN STATES OF... dehydrate. To can, freeze, or dehydrate means to convert cranberries into canned, frozen, or dehydrated cranberries or other cranberry products by any commercial process....

  12. Water-loss dehydration and aging.

    PubMed

    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.

  13. Dehydration Processes of Sugar Glasses and Crystals

    NASA Astrophysics Data System (ADS)

    Seo, Jeong-Ah; Kwon, Hyun-Joung; Kim, Hyung Kook; Hwang, Yoon-Hwae

    2006-05-01

    The dehydration processes of sugar glasses and sugar crystals were studied by using Thermogravimetry — Differential Thermal Analysis method. We used three monosaccharide sugars (fructose, galactose, and glucose) and three disaccharide sugars (sucrose, maltose and trehalose). It was found that a trehalose showed different dehydration process compared to the other sugars. The amount of mass reductions in sugar glasses is larger than that in sugar crystals. However, in the case of trehalose, the amount of mass reduction in trehalose glasses is smaller than that in trehalose crystals. It seems to be possible that this unique dehydration property of trehalose glasses maybe relate to the cell protection ability during an anhydrobiosis process.

  14. Dehydration resistance of liposomes containing trehalose glycolipids

    NASA Astrophysics Data System (ADS)

    Nyberg, Kendra; Goulding, Morgan; Parthasarathy, Raghuveer

    2010-03-01

    The pathogen, Mycobacterium tuberculosis, has an unusual outer membrane containing trehalose glycolipids that may contribute to its ability to survive freezing and dehydration. Based on our recent discovery that trehalose glycolipids confer dehydration resistance to supported lipid monolayers (Biophys. J. 94: 4718-4724 (2008); Langmuir 25: 5193-5198, (2009)), we hypothesized that liposomes containing synthetic trehalose glycolipids may be dehydration-resistant as well. To test this, we measured the leakage of encapsulated fluorophores and larger macromolecular cargo from such liposomes subject to freeze drying. Both leakage assays and size measurements show that the liposomes are dehydration-resistant. In addition to demonstrating a possibly technologically useful encapsulation platform, our results corroborate the view that encapsulation in a trehalose-glycolipid-rich membrane is a biophysically viable route to protection of mycobacteria from environmental stresses.

  15. DEHYDRATION OF LOW WATER CONTENT ETHANOL

    EPA Science Inventory

    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...

  16. Problem: Thirst, Drinking Behavior, and Involuntary Dehydration

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    1992-01-01

    The phenomenon of involuntary dehydration, the delay in full restoration of a body water deficit by drinking, has been described extensively but relatively little is known about its physiological mechanism. It occurs primarily in humans when they are exposed to various stresses including exercise, environmental heat and cold, altitude, water immersion, dehydration, and perhaps microgravity, singly and in various combinations. The level of involuntary dehydration is approximately proportional to the degree of total stress imposed on the body. Involuntary dehydration appears to be controlled by more than one factor including social customs that influence what is consumed, the capacity and rate of fluid absorption from the gastrointestinal system, the level of cellular hydration involving the osmotic-vasopressin interaction with sensitive cells or structures in the central nervous system, and, to a lesser extent, hypovolemic-angiotensin II stimuli. Since humans drink when there is no apparent physiological stimulus, the psychological component should always be considered when investigating the total mechanisms for drinking.

  17. Dehydration processes using membranes with hydrophobic coating

    DOEpatents

    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.

  18. Freeze-Dehydration by Microwave Energy

    DTIC Science & Technology

    1974-12-01

    MATHEMATICAL MODEL DEHYDRATED FOODS ENERGY BEEF EQUATIONS FREEZE DRIED FOODS BEATING ANALYSIS MELTING FREEZE DRYING MICROWAVES MICROWAVE DIELECTRIC ...d) 20. Abstract (continued) The model is applied to simulate the freeze-dehydration of beef meat by microwave dielectric heating at 2450 MHz . The...8 3.3 Dielectric Properties •••.•. .••••....• 8 3.4 Specific Heat of Frozen and Dried Beef

  19. Plastic and dehydration instabilities of antigorite serpentinite

    NASA Astrophysics Data System (ADS)

    Ando, J.; Katayama, I.; Ohfuji, H.; Terada, Y.

    2008-12-01

    We conducted a constant displacement rate test of antigorite serpentinite by a triaxial solid medium deformation apparatus installed at Hiroshima University. Experimental conditions were P = ca. 1.0 GPa, T = 450 C to 800 C, which cover from stability to dehydration conditions of antigorite, and strain rate of digit of 10-5 /sec. Samples were cylindrical shape cored from serpentinite and their sizes were 7 mm x 7 mm and 5 mm x 5 mm in diameter by length. Faults were observed in recovered samples from all temperature conditions. Mechanical data of faulted samples showed stress drop of several 10 MPa during experiments. The followings summarize microstructural observations of the recovered samples, and propose generation processes of fault at stability and dehydration conditions. 1) Stability field (plastic instability): Antigorite grains develop a lattice preferred orientation (LPO) along a fault, which characterized by (001) cleavage face parallel to fault plane. This fact suggests the fault is generated by the following process. i) Antigorite grains on the plane applied by maximum shear stress are preferentially deformed by plastic manner, and then develop the LPO. ii) The arrangement of cleavage face gradually reduces the strength of this plane. iii) Eventually, embrittlement occurs at the critical point when the rock strength along this weak plane becomes smaller than shear stress. 2) Dehydration condition (dehydration instability): Fine grained dehydration phases less than 1 micrometer in size such as olivine and talc are detected as a thin vein along the fault. Moreover, talc and olivine, or antigorite ca. 1 - 5 micrometers in size with angular shape are observed within the fault as a fault gauge. These facts suggest the following generation process of fault. i) Dehydration reaction of antigorite begins on the plane applied by maximum shear stress and expands along this plane. ii) The dehydration gradually reduces the strength of this plane. iii) Eventually

  20. Dehydration kinetics of talc at 1 bar

    NASA Technical Reports Server (NTRS)

    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.

  1. Geothermal demonstration: Zunil food dehydration facility

    SciTech Connect

    Maldonado, O. ); Altseimer, J.; Thayer, G.R. ); Cooper, L. ); Caicedo, A. . Inst. Nacional de Electrificacion)

    1991-08-01

    A food dehydration facility was constructed near the town of Zunil, Guatemala, to demonstrate the use of geothermal energy for industrial applications. The facility, with some modifications to the design, was found to work quite satisfactorily. Tests using five different products were completed during the time geothermal energy was used in the plant. During the time the plant was not able to use geothermal energy, a temporary diesel-fueled boiler provided the energy to test dehydration on seven other crops available in this area. The system demonstrates that geothermal heat can be used successfully for dehydrating food products. Many other industrial applications of geothermal energy could be considered for Zunil since a considerable amount of moderate-temperature heat will become available when the planned geothermal electrical facility is constructed there. 6 refs., 15 figs., 7 tabs.

  2. Oxidative stress and its effects during dehydration.

    PubMed

    França, M B; Panek, A D; Eleutherio, E C A

    2007-04-01

    Water is usually thought to be required for the living state, but several organisms are capable of surviving complete dehydration (anhydrobiotes). Elucidation of the mechanisms of tolerance against dehydration may lead to development of new methods for preserving biological materials that do not normally support drying, which is of enormous practical importance in industry, in clinical medicine as well as in agriculture. One of the molecular mechanisms of damage leading to death in desiccation-sensitive cells upon drying is free-radical attack to phospholipids, DNA and proteins. This review aims to summarize the strategies used by anhydrobiotes to cope with the danger of oxygen toxicity and to present our recent results about the importance of some antioxidant defense systems in the dehydration tolerance of Saccharomyces cerevisiae, a usual model in the study of stress response.

  3. Dehydration in the Winter Arctic Tropopause Region

    NASA Technical Reports Server (NTRS)

    Pfister, Leonhard; Jensen, Eric; Podolske, James; Selkirk, Henry; Anderson, Bruce; Avery, Melody; Diskin. Glenn

    2004-01-01

    Recent work has shown that limited amounts of tropospheric air can penetrate as much as 1 km into the middleworld stratosphere during the arctic winter. This, coupled with temperatures that are cold enough to produce saturation mixing ratios of less than 5 ppmv at the tropopause, results in stratospheric cloud formation and upper tropospheric dehydration. Even though these "cold outbreaks" occupy only a small portion of the area in the arctic (1-2%), their importance is magnified by an order of magnitude because of the air flow through them. This is reinforced by evidence of progressive drying through the winter measured during SOLVE-1. The significance of this process lies in its effect on the upper tropospheric water content of the middle and high latitude tropopause region, which plays an important role in regulating the earth's radiative balance. There appears to be significant year-to-year variability in the incidence of the cold outbreaks. This work has two parts. First, we describe case studies of dehydration taken from the SOLVE and SOLVE2 aircraft sampling missions during the Arctic winters of 2000 and 2003 respectively. Trajectory based microphysical modeling is employed to examine the sensitivity of the dehydration to microphysical parameters and the nature of sub-grid scale temperature fluctuations. We then examine the year-to-year variations in potential dehydration using a trajectory climatology.

  4. Thermoelastic behavior and dehydration process of cancrinite

    NASA Astrophysics Data System (ADS)

    Gatta, G. D.; Comboni, D.; Alvaro, M.; Lotti, P.; Cámara, F.; Domeneghetti, M. C.

    2014-05-01

    The high-temperature thermoelastic behavior of a natural cancrinite has been investigated by in situ single-crystal X-ray diffraction. The unit-cell volume variation as a function of temperature ( T) exhibits a continuous trend up to 748 K (hydrous expansion regime). The unit-cell edges expansion clearly shows an anisotropic expansion scheme ( α a < α c ). At 748 K, a dehydration process takes place, and a series of unit-cell parameter measurements at constant temperature (748 K) for a period of 12 days indicate that the dehydration process continued for the entire period of time, until the cell parameters were found to be constant. After the dehydration process is completed, the structure expands almost linearly with increasing temperature up to 823 K, where a sudden broadening of the diffraction peaks, likely due to the impending decomposition, did not allow the collection of further data points. Even with a very limited temperature range for the anhydrous regime, we observed that the behavior of the two (i.e., hydrous and anhydrous) high-temperature structures is similar in terms of (1) volume thermal expansion coefficient and (2) thermoelastic anisotropy. The structure refinements based on the data collected at 303, 478 and 748 K (after the dehydration), respectively, showed a change in the mechanism of tilting of the quasi-rigid (Si,Al)O4 tetrahedra, following the loss of H2O molecules, ascribable to the high-temperature Na+ coordination environment within the cages.

  5. Voluntary Dehydration and Alliesthesia for Water,

    DTIC Science & Technology

    1983-05-13

    of the extracellular fluid are maintained in dynamic balance, and partially controlled by antidiuretic hormone and thirst (2). The drive to drink...dehydration which limits sweating, adversely affects cardiovascular and thermoregulatory functions , and predisposes to heat illness. Emphasis on drinking by

  6. Thermodynamic stability considerations for isostructural dehydrates.

    PubMed

    Murphy, Brendan J; Casteel, Melissa J; Samas, Brian; Krzyzaniak, Joseph F

    2012-04-01

    Nonstoichiometric channel hydrates are a class of crystalline hydrates that can incorporate a range of water levels as a function of temperature and relative humidity (RH). When a nonstoichiometric channel hydrate can dehydrate to yield a physically stable isostructural crystalline lattice, it may become challenging to accurately evaluate the thermodynamic stability relationship associated with a polymorphic system using traditional methods. This work demonstrates application of a eutectic-melting method to determine the stability relationship between a nonstoichiometric channel dehydrate and an anhydrous form. A transition temperature (122°C) between the isostructural dehydrate of the nonstoichiometric channel hydrate and the anhydrous polymorph was identified, with the nonstoichiometric channel hydrate being the thermodynamically stable anhydrous form at room temperature (RT). Solid-state storage at a range of RH conditions demonstrated that the nonstoichiometric channel hydrate is also the stable form at RT above an RH of 94%. These results demonstrate that the nonstoichiometric channel hydrate is the stable form at low temperatures, independent of its hydration state. It has been demonstrated that the eutectic-melting method is applicable to the study of thermodynamic stability relationships between anhydrous forms and dehydrated channel hydrates.

  7. Pelagic sea snakes dehydrate at sea

    PubMed Central

    Lillywhite, Harvey B.; Sheehy, Coleman M.; Brischoux, François; Grech, Alana

    2014-01-01

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans. PMID:24648228

  8. Pelagic sea snakes dehydrate at sea.

    PubMed

    Lillywhite, Harvey B; Sheehy, Coleman M; Brischoux, François; Grech, Alana

    2014-05-07

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans.

  9. 21 CFR 73.40 - Dehydrated beets (beet powder).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Identity. (1) The color additive dehydrated beets is a dark red powder prepared by dehydrating sound... specifications: Volatile matter, not more than 4 percent. Acid insoluble ash, not more than 0.5 percent. Lead...

  10. 21 CFR 73.40 - Dehydrated beets (beet powder).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) Identity. (1) The color additive dehydrated beets is a dark red powder prepared by dehydrating sound... specifications: Volatile matter, not more than 4 percent. Acid insoluble ash, not more than 0.5 percent. Lead...

  11. 21 CFR 73.40 - Dehydrated beets (beet powder).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Identity. (1) The color additive dehydrated beets is a dark red powder prepared by dehydrating sound... specifications: Volatile matter, not more than 4 percent. Acid insoluble ash, not more than 0.5 percent. Lead...

  12. 21 CFR 73.40 - Dehydrated beets (beet powder).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Identity. (1) The color additive dehydrated beets is a dark red powder prepared by dehydrating sound... specifications: Volatile matter, not more than 4 percent. Acid insoluble ash, not more than 0.5 percent. Lead...

  13. 21 CFR 73.40 - Dehydrated beets (beet powder).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) Identity. (1) The color additive dehydrated beets is a dark red powder prepared by dehydrating sound... specifications: Volatile matter, not more than 4 percent. Acid insoluble ash, not more than 0.5 percent. Lead...

  14. ADVANCED DEHYDRATOR DESIGN SAVES GAS AND REDUCES HAP EMISSIONS

    EPA Science Inventory

    Glycol dehydrators remove water from gas pipe lines. An advanced dehydrator by Engineered Concepts, Farmington, NM, saves a significant amount of gas, while reducing hazardous air pollutants, volatile organic compounds and CO2 air pollutants

  15. Treatment of Dredged Sludge By Mechanical Dehydration,

    DTIC Science & Technology

    there is an urgent need to reduce both the volume of dredged sludge and the size of the disposal area. This mechanical method is different from the...conventional engineering dehydration by loading, consolidation, and drainage in that the dredged sludge is separated into sludge cakes and clean water...turbidity in water. This mechanical sludge treatment technique can be most efficient when used in combination with a pump dredge. This method offers

  16. Dehydration, Hyperthermia, and Athletes: Science and Practice

    PubMed Central

    Murray, Robert

    1996-01-01

    Objective: To present the recent research that underscores the value of preventing both dehydration and hyperthermia. Such efforts will improve the athlete's capacity to perform physical activity and reduce the risk of heat-related problems. Data Sources: Data were drawn from an extensive review of the scientific literature over the past 50 years with an emphasis on recent research (> 1990) that focuses on the physiological and performance benefits of fluid replacement. Data Synthesis: Even low levels of dehydration (eg, less than a 2% loss of body weight) impair cardiovascular and thermoregulatory response and reduce the capacity for exercise. Heat exposure also reduces the athlete's ability to train and compete, an effect that can be independent of hydration status. Even if athletes are well hydrated, hot weather alone will reduce their capacity to exercise. Optimal performance is possible only when dehydration and hyperthermia are minimized by ingesting ample volumes of fluid during exercise and by taking common-sense precautions in keeping cool. Recent research has demonstrated that consuming fluid in volumes approximating sweat loss maintains important physiological functions and significantly improves exercise performance, even during exercise lasting only 1 hour. Carbohydrate ingestion also improves exercise performance, an effect that is independent of, and additive to, preventing dehydration. Conclusion/Application: Athletes should follow an aggressive fluid replacement and temperature regulation regimen. Successful implementation of this regimen requires that athletic trainers, coaches, athletes, and support personnel are made aware of the benefits of adequate fluid replacement, that appropriate fluid replacement strategies are developed and implemented, that athletes have the opportunity to train themselves to ingest larger volumes of fluid more frequently, and that other practical steps are taken to keep athletes cool during both training and

  17. Dehydration-induced drinking in humans

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.

    1982-01-01

    The human tendency to experience a delay in rehydration (involuntary dehydration) after fluid loss is considered. The two primary factors contributing to involuntary dehydration are probably upright posture, and extracellular fluid and electrolyte loss by sweating from exercise and heat exposure. First, as the plasma sodium and osmotic concentrations remain virtually unchanged for supine to upright postural changes, the major stimuli for drinking appear to be associated with the hypovolemia and increase in the renin-angiotension system. Second, voluntary drinking during the heat experiments was 146% greater than in cool experiments; drinking increased by 109% with prior dehydration as opposed to normal hydration conditions; and drinking was increased by 41% after exercise as compared with the resting condition. Finally, it is concluded that the rate of sweating and the rate of voluntary fluid intake are highly correlated, and that the dispogenic factors of plasma volume, osmolality, and plasma renin activity are unrelated to sweat rate, but are likely to induce drinking in humans.

  18. Fasting headache, weight loss, and dehydration.

    PubMed

    Mosek, A; Korczyn, A D

    1999-03-01

    Recently, we showed that fasting is a strong headache precipitator unrelated to coffee, tea, or smoking withdrawal or to oversleeping. In the current study, we evaluated the role of dehydration as a possible precipitator of fasting headache. The effects of a 25-hour fast of the Jewish Yom Kippur (Day of Atonement) were studied in women who participated in our previous Yom Kippur study. We asked the subjects to weigh themselves at the beginning and at the end of the Yom Kippur fast, assuming that the weight loss would largely reflect dehydration. In all but 1 of the 56 participants, the fast resulted in weight loss but only 28 (50%) reported headache. The average weight loss was 1.4 +/- 0.8 kg in those who developed headache and 1.2 +/- 0.5 kg in those who did not. This small difference was not statistically significant. We conclude that dehydration, as reflected by acute weight loss, is an unlikely cause of headache during a single day of fasting. The mechanism of fasting headache remains unclear.

  19. Biomass energy analysis for crop dehydration

    SciTech Connect

    Whittier, J.P.; Haase, S.G.; Quinn, M.W.; Zachritz, W.; Lansford, R.; Swanson, D.

    1995-06-01

    In 1994, an agricultural processing facility began constructing a new spice and herb dehydration facility in southern New Mexico. Because of the considerable energy intensity of the dehydration operation, management of energy costs is of special concern to the facility. Biomass energy conversion offers the potential for firms to reduce annual operating costs-especially firms with access to low-cost resources. Because the selected facility produces a biomass by-product as a result of its dehydration operation, it is appropriate to explore the technical, regulatory, institutional and economic conditions that affect the successful utilization of biomass resources. The facility is characterized as a small-scale installation, relative to other energy users. In this context, small-scale represents less than 100 million Btu per hour of thermal load and less than 1 MWe of electrical load. However, the projected annual energy bill is approximately $1.1 million and represents a significant portion of operational costs for the firm. For this study, the biomass resources in southern New Mexico and western Texas are detailed. Annual supplies of various biomass resources (i.e., wood chips, pecan shells, discarded tires and cotton gin trash) were inventoried. Further, delivered costs are projected for each of the resource forms. A technical assessment for the small-scale gasification and combustion systems is presented.

  20. May eclogite dehydration cause slab fracturation ?

    NASA Astrophysics Data System (ADS)

    Loury, Chloé; Lanari, Pierre; Rolland, Yann; Guillot, Stéphane; Ganino, Clément

    2015-04-01

    Petrological and geophysical evidences strongly indicate that fluids releases play a fundamental role in subduction zones as in subduction-related seismicity and arc magmatism. It is thus important to assess quantitatively their origin and to try to quantify the amount of such fluids. In HP metamorphism, it is well known that pressure-dependent dehydration reactions occur during the prograde path. Many geophysical models show that the variations in slab physical properties along depth could be linked to these fluid occurrences. However it remains tricky to test such models on natural sample, as it is difficult to assess or model the water content evolution in HP metamorphic rocks. This difficulty is bound to the fact that these rocks are generally heterogeneous, with zoned minerals and preservation of different paragenesis reflecting changing P-T conditions. To decipher the P-T-X(H2O) path of such heterogeneous rocks the concept of local effective bulk (LEB) composition is essential. Here we show how standardized X-ray maps can be used to constrain the scale of the equilibration volume of a garnet porphyroblast and to measure its composition. The composition of this equilibrium volume may be seen as the proportion of the rock likely to react at a given time to reach a thermodynamic equilibrium with the growing garnet. The studied sample is an eclogite coming from the carboniferous South-Tianshan suture (Central Asia) (Loury et al. in press). Compositional maps of a garnet and its surrounding matrix were obtained from standardized X-ray maps processed with the program XMapTools (Lanari et al, 2014). The initial equilibration volume was modeled using LEB compositions combined together with Gibbs free energy minimization. P-T sections were calculated for the next stages of garnet growth taking into account the fractionation of the composition at each stage of garnet growth. The modeled P-T-X(H2O) path indicates that the rock progressively dehydrates during the

  1. Dehydration of football referees during a match

    PubMed Central

    Da Silva, A I; Fernandez, R

    2003-01-01

    Objectives: To study hydration status in referees (main) and assistant referees (linesmen) during official football matches. Methods: Twelve male football referees were evaluated; all were volunteers. Before and after each match, the referee and one of the assistants were weighed without clothes and a blood sample was taken. Total water loss was determined for each subject from the change in body weight. The main haematological variables were analysed in the blood samples. Total plasma protein concentration and osmolarity were also determined. Variation in plasma volume was determined from changes in packed cell volume and a combination of changes in packed cell volume and haemoglobin concentrations. Results: During a match, total body water loss was 1.60 (0.13) litres, equivalent to 2.05 (0.18)% of body weight. Body weight was reduced by 1.55 (0.12)%, showing that water ingestion during the interval replaces only 24.4% of the body fluids lost during the match. The assistants lost 0.79 (0.19) litre of water, equivalent to 1.05 (0.25)% of body weight. The referees showed a significant decrease in plasma volume of 4.99 (1.33)%. The assistants showed a non-significant increase in plasma volume. The reduction in plasma volume observed in the referees correlated significantly with total body water loss (r = 0.9623). From these data, it is possible to predict that a dehydration of 1% reflects a reduction in plasma volume of nearly 2.5%. Conclusions: Referees are moderately dehydrated after a football match (2%), whereas assistants show a non-significant dehydration of 1% of their body weight. PMID:14665588

  2. Dehydration of plutonium or neptunium trichloride hydrate

    DOEpatents

    Foropoulos, Jr., Jerry; Avens, Larry R.; Trujillo, Eddie A.

    1992-01-01

    A process of preparing anhydrous actinide metal trichlorides of plutonium or neptunium by reacting an aqueous solution of an actinide metal trichloride selected from the group consisting of plutonium trichloride or neptunium trichloride with a reducing agent capable of converting the actinide metal from an oxidation state of +4 to +3 in a resultant solution, evaporating essentially all the solvent from the resultant solution to yield an actinide trichloride hydrate material, dehydrating the actinide trichloride hydrate material by heating the material in admixture with excess thionyl chloride, and recovering anhydrous actinide trichloride is provided.

  3. Dehydration of plutonium or neptunium trichloride hydrate

    DOEpatents

    Foropoulos, J. Jr.; Avens, L.R.; Trujillo, E.A.

    1992-03-24

    A process is described for preparing anhydrous actinide metal trichlorides of plutonium or neptunium by reacting an aqueous solution of an actinide metal trichloride selected from the group consisting of plutonium trichloride or neptunium trichloride with a reducing agent capable of converting the actinide metal from an oxidation state of +4 to +3 in a resultant solution, evaporating essentially all the solvent from the resultant solution to yield an actinide trichloride hydrate material, dehydrating the actinide trichloride hydrate material by heating the material in admixture with excess thionyl chloride, and recovering anhydrous actinide trichloride.

  4. Intrastab Earthquakes: Dehydration of the Cascadia Slab

    USGS Publications Warehouse

    Preston, L.A.; Creager, K.C.; Crosson, R.S.; Brocher, T.M.; Trehu, A.M.

    2003-01-01

    We simultaneously invert travel times of refracted and wide-angle reflected waves for three-dimensional compressional-wave velocity structure, earthquake locations, and reflector geometry in northwest Washington state. The reflector, interpreted to be the crust-mantle boundary (Moho) of the subducting Juan de Fuca plate, separates intrastab earthquakes into two groups, permitting a new understanding of the origins of intrastab earthquakes in Cascadia. Earthquakes up-dip of the Moho's 45-kilometer depth contour occur below the reflector, in the subducted oceanic mantle, consistent with serpentinite dehydration; earthquakes located down-dip occur primarily within the subducted crust, consistent with the basalt-to-eclogite transformation.

  5. Dehydration anorexia is attenuated in oxytocin-deficient mice.

    PubMed

    Rinaman, Linda; Vollmer, Regis R; Karam, Joseph; Phillips, Donnesha; Li, Xia; Amico, Janet A

    2005-06-01

    Evidence in rats suggests that central oxytocin (OT) signaling pathways contribute to suppression of food intake during dehydration (i.e., dehydration anorexia). The present study examined water deprivation-induced dehydration anorexia in wild-type and OT -/- mice. Mice were deprived of food alone (fasted, euhydrated) or were deprived of both food and water (fasted, dehydrated) for 18 h overnight. Fasted wild-type mice consumed significantly less chow during a 60-min refeeding period when dehydrated compared with their intake when euhydrated. Conversely, fasting-induced food intake was slightly but not significantly suppressed by dehydration in OT -/- mice, evidence for attenuated dehydration anorexia. In a separate experiment, mice were deprived of water (but not food) overnight for 18 h; then they were anesthetized and perfused with fixative for immunocytochemical analysis of central Fos expression. Fos was elevated similarly in osmo- and volume-sensitive regions of the basal forebrain and hypothalamus in wild-type and OT -/- mice after water deprivation. OT-positive neurons expressed Fos in dehydrated wild-type mice, and vasopressin-positive neurons were activated to a similar extent in wild-type and OT -/- mice. Conversely, significantly fewer neurons within the hindbrain dorsal vagal complex were activated in OT -/- mice after water deprivation compared with activation in wild-type mice. These findings support the view that OT-containing projections from the hypothalamus to the hindbrain are necessary for the full expression of compensatory behavioral and physiological responses to dehydration.

  6. Effects of Dehydration on Fish Muscles at Chilled Temperature

    NASA Astrophysics Data System (ADS)

    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.

  7. Biomass energy analysis for crop dehydration

    SciTech Connect

    Whittier, J.P.; Haase, S.G.; Quinn, M.W.

    1994-12-31

    In 1994, an agricultural processing facility was constructed in southern New Mexico for spice and herb dehydration. Annual operational costs are dominated by energy costs, due primarily to the energy intensity of dehydration. A feasibility study was performed to determine whether the use of biomass resources as a feedstock for a cogeneration system would be an economical option. The project location allowed access to unusual biomass feedstocks including cotton gin trash, pecan shells and in-house residues. A resource assessment of the immediate project area determined that approximately 120,000 bone dry tons of biomass feedstocks are available annually. Technology characterization for the plant energy requirements indicated gasification systems offer fuel flexibility advantages over combustion systems although vendor support and commercial experience are limited. Regulatory siting considerations introduce a level of uncertainty because of a lack of a precedent in New Mexico for gasification technology and because vendors of commercial gasifiers have little experience operating such a facility nor gathering emission data. A public opinion survey indicated considerable support for renewable energy use and biomass energy utilization. However, the public opinion survey also revealed limited knowledge of biomass technologies and concerns regarding siting of a biomass facility within the geographic area. The economic analysis conducted for the study is based on equipment vendor quotations, and indicates there will be difficulty competing with current prices of natural gas.

  8. Cryoprotective dehydration is widespread in Arctic springtails.

    PubMed

    Sørensen, Jesper Givskov; Holmstrup, Martin

    2011-08-01

    Cryoprotective dehydration (CPD) is a cold tolerance strategy employed by small invertebrates that readily lose water by evaporation when subjected to sub-zero temperatures in the presence of ice. Until now, relatively few species have been investigated using methods by which CPD can be shown. In the present study we investigated the cold tolerance strategy of seven soil arthropod species from the high Arctic Spitzbergen, and compared water content and water loss, body fluid melting points (MP) and survival under cold and desiccating conditions. We tested the hypothesis that CPD is a commonly occurring cold hardiness strategy among soil arthropods. We found that four springtail species (Hypogastrura viatica, Folsomia quadrioculata, Oligaphorura groenlandica and Megaphorura arctica; Collembola) went through severe dehydration and MP equilibration with ambient temperature, and thus overwinter by employing CPD, whereas a beetle (Atheta graminicola) and one of the springtails (Isotoma anglicana) were typical freeze avoiding species over-wintering by supercooling. Desiccation tolerance of the red velvet mite (Neomolgus littoralis) was also investigated; very low water loss rates of this species indicated that it does not survive winter by use of CPD. All in all, the results of the present study confirm the hypothesis that CPD is an effective over-wintering strategy which is widespread within soil arthropods.

  9. Dehydration-mediated cluster formation of nanoparticles

    NASA Astrophysics Data System (ADS)

    Ahn, Sungsook; Joon Lee, Sang

    2015-06-01

    Drying procedure is a powerful method to modulate the bottom-up assembly of basic building component. The initially weak attraction between the components screened in a solution strengthens as the solvent evaporates, organizing the components into structures. Drying is process-dependent, irreversible, and nonequilibrated, thus the mechanism and the dynamics are influenced by many factors. Therefore, the interaction of the solvent and the elements during the drying procedure as well as the resulting pattern formations are strongly related. Nonetheless still many things are open in questions in terms of their dynamics. In this study, nanoscale dehydration procedure is experimentally investigated using a nanoparticle (NP) model system. The role of water is verified in a single NP scale and the patterns of collective NP clusters are determined. Stepwise drying procedures are proposed based on the location from which water is removed. Effective water exodus from a unit NP surface enhances the attractive interaction in nanoscale and induces heterogeneous distribution in microscale. This study provides fundamental proof of systematic relation between the dehydration process and the resultant cluster patterns in hierarchical multiscales.

  10. Dehydration-driven topotaxy in subduction zones

    NASA Astrophysics Data System (ADS)

    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

  11. Observations on saliva osmolality during progressive dehydration and partial rehydration.

    PubMed

    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.

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

    MedlinePlus

    ... Video: Getting an X-ray What's the Big Sweat About Dehydration? KidsHealth > For Kids > What's the Big Sweat About Dehydration? Print A A A What's in ... When it's hot outside and you've been sweating, you get thirsty. Why? Thirst can be a ...

  13. Dehydration and drinking responses in a pelagic sea snake.

    PubMed

    Lillywhite, Harvey B; Brischoux, François; Sheehy, Coleman M; Pfaller, Joseph B

    2012-08-01

    Recent investigations of water balance in sea snakes demonstrated that amphibious sea kraits (Laticauda spp.) dehydrate in seawater and require fresh water to restore deficits in body water. Here, we report similar findings for Pelamis platurus, a viviparous, pelagic, entirely marine species of hydrophiine ("true") sea snake. We sampled snakes at Golfo de Papagayo, Guanacaste, Costa Rica and demonstrated they do not drink seawater but fresh water at variable deficits of body water incurred by dehydration. The threshold dehydration at which snakes first drink fresh water is -18.3 ± 1.1 % (mean ± SE) loss of body mass, which is roughly twice the magnitude of mass deficit at which sea kraits drink fresh water. Compared to sea kraits, Pelamis drink relatively larger volumes of water and make up a larger percentage of the dehydration deficit. Some dehydrated Pelamis also were shown to drink brackish water up to 50% seawater, but most drank at lower brackish values and 20% of the snakes tested did not drink at all. Like sea kraits, Pelamis dehydrate when kept in seawater in the laboratory. Moreover, some individuals drank fresh water immediately following capture, providing preliminary evidence that Pelamis dehydrate at sea. Thus, this widely distributed pelagic species remains subject to dehydration in marine environments where it retains a capacity to sense and to drink fresh water. In comparison with sea kraits, however, Pelamis represents a more advanced stage in the evolutionary transition to a fully marine life and appears to be less dependent on fresh water.

  14. Smackerels of Somethings: Dehydrating Food and How to Use It.

    ERIC Educational Resources Information Center

    Ditzler, Carmen

    1994-01-01

    Provides ideas about how to add variety, flavor, texture, and nutrition to outdoor meals by dehydrating food and using it on camping trips. The goal is to prepare nutritious and appealing meals without spending a lot of money on commercially dehydrated or freeze-dried foods. Includes instructions for rehydrating foods. (LP)

  15. Response of Chinese wampee axes and maize embryos to dehydration at different rates.

    PubMed

    Huang, Hui; Song, Song-Quan; Wu, Xian-Jin

    2009-01-01

    Survival of wampee (Clausena lansiumSkeels) axes and maize (Zea mays L.) embryos decreased with rapid and slow dehydration. Damage of wampee axes by rapid dehydration was much less than by slow dehydration, and that was contrary to maize embryos. The malondialdehyde contents of wampee axes and maize embryos rapidly increased with dehydration, those of wampee axes were lower during rapid dehydration than during slow dehydration, and those of maize embryos were higher during rapid dehydration than during slow dehydration. Activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) of wampee axes markedly increased during the early phase of dehydration, and then rapidly decreased, and those of rapidly dehydrated axes were higher than those of slow dehydrated axes when they were dehydrated to low water contents. Activities of SOD and APX of maize embryos notable decreased with dehydration. There were higher SOD activities and lower APX activities of slowly dehydrated maize embryos compared with rapidly dehydrated maize embryos. CAT activities of maize embryos markedly increased during the early phase of dehydration, and then decreased, and those of slowly dehydrated embryos were higher than those of rapidly dehydrated embryos during the late phase of dehydration.

  16. Two-stage dehydration of sugars

    DOEpatents

    Holladay, Johnathan E.; Hu, Jianli; Wang, Yong; Werpy, Todd A.

    2009-11-10

    The invention includes methods for producing dianhydrosugar alcohol by providing an acid catalyst within a reactor and passing a starting material through the reactor at a first temperature. At least a portion of the staring material is converted to a monoanhydrosugar isomer during the passing through the column. The monoanhydrosugar is subjected to a second temperature which is greater than the first to produce a dianhydrosugar. The invention includes a method of producing isosorbide. An initial feed stream containing sorbitol is fed into a continuous reactor containing an acid catalyst at a temperature of less than 120.degree. C. The residence time for the reactor is less than or equal to about 30 minutes. Sorbitol converted to 1,4-sorbitan in the continuous reactor is subsequently provided to a second reactor and is dehydrated at a temperature of at least 120.degree. C. to produce isosorbide.

  17. Improving diffraction resolution using a new dehydration method.

    PubMed

    Huang, Qingqiu; Szebenyi, Doletha M E

    2016-02-01

    The production of high-quality crystals is one of the major obstacles in determining the three-dimensional structure of macromolecules by X-ray crystallography. It is fairly common that a visually well formed crystal diffracts poorly to a resolution that is too low to be suitable for structure determination. Dehydration has proven to be an effective post-crystallization treatment for improving crystal diffraction quality. Several dehydration methods have been developed, but no single one of them is suitable for all crystals. Here, a new convenient and effective dehydration method is reported that makes use of a dehydrating solution that will not dry out in air for several hours. Using this dehydration method, the resolution of Archaeoglobus fulgidus Cas5a crystals has been increased from 3.2 to 1.95 Å and the resolution of Escherichia coli LptA crystals has been increased from <5 to 3.4 Å.

  18. Formation and dehydration enthalpy of potassium hexaniobate

    DOE PAGES

    Sahu, Sulata K.; Boatner, Lynn A.; Navrotsky, Alexandra

    2016-09-15

    The formation energetics of hydrous and dehydrated potassium hexaniobates are investigated using high-temperature oxide melt solution calorimetry. The enthalpies of formation of K4Nb6O17 and K4Nb6O17•3H2O from oxides are (–864.42 ± 10.63) and (–899.32 ± 11.48) kJ/mol, respectively. The formation enthalpy of K4Nb6O17 from elements is (–7289.64 ± 12.50) kJ/mol, and of K4Nb6O17•3H2O is (–8181.94 ± 13.24) kJ/mol. The enthalpy of dehydration (ΔHdehy) for the reaction K4Nb6O173H2O (xl, 25 °C) = K4Nb6O17 (xl, 25 °C) + 3H2O (l, 25 °C) is endothermic and is 34.60 ± 7.56 kJ/mol. The ΔHdehy per mole of water, 11.53 ± 2.52 kJ/mol, indicates the watermore » molecules in K4Nb6O17•3H2O are not just physically adsorbed, but loosely bonded in the K4Nb6O17 phase, presumably in specific interlayer sites. As a result, the loss of this water near 100 °C on heating is consistent with the weak bonding of water.« less

  19. DMSO induces dehydration near lipid membrane surfaces.

    PubMed

    Cheng, Chi-Yuan; Song, Jinsuk; Pas, Jolien; Meijer, Lenny H H; Han, Songi

    2015-07-21

    Dimethyl sulfoxide (DMSO) has been broadly used in biology as a cosolvent, a cryoprotectant, and an enhancer of membrane permeability, leading to the general assumption that DMSO-induced structural changes in cell membranes and their hydration water play important functional roles. Although the effects of DMSO on the membrane structure and the headgroup dehydration have been extensively studied, the mechanism by which DMSO invokes its effect on lipid membranes and the direct role of water in this process are unresolved. By directly probing the translational water diffusivity near unconfined lipid vesicle surfaces, the lipid headgroup mobility, and the repeat distances in multilamellar vesicles, we found that DMSO exclusively weakens the surface water network near the lipid membrane at a bulk DMSO mole fraction (XDMSO) of <0.1, regardless of the lipid composition and the lipid phase. Specifically, DMSO was found to effectively destabilize the hydration water structure at the lipid membrane surface at XDMSO <0.1, lower the energetic barrier to dehydrate this surface water, whose displacement otherwise requires a higher activation energy, consequently yielding compressed interbilayer distances in multilamellar vesicles at equilibrium with unaltered bilayer thicknesses. At XDMSO >0.1, DMSO enters the lipid interface and restricts the lipid headgroup motion. We postulate that DMSO acts as an efficient cryoprotectant even at low concentrations by exclusively disrupting the water network near the lipid membrane surface, weakening the cohesion between water and adhesion of water to the lipid headgroups, and so mitigating the stress induced by the volume change of water during freeze-thaw.

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

    PubMed

    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.

  1. Dehydration indicators for broiler chickens at slaughter.

    PubMed

    Vanderhasselt, R F; Buijs, S; Sprenger, M; Goethals, K; Willemsen, H; Duchateau, L; Tuyttens, F A M

    2013-03-01

    Freedom of (prolonged) thirst is considered to be of paramount importance for animal welfare. This emotion normally results from dehydration, which can be measured using physiological indicators. Because no reliable physiological indicator for thirst was available for broilers, we aimed to identify such a measure in this study. This indicator would ideally be integrated into quality control systems in commercial slaughter plants. In the first experiment, water deprivation was manipulated systematically by withdrawing water for different durations (total water withdrawal for 0 (control), 24, 36, or 48 h, or a 10-d period with restricted access to water for 2 times 10 min per day). A significant decrease in drained blood content and BW occurred from 36 h of total water deprivation onward (both P = 0.03), whereas long-term restricted access tended to decrease drained blood content (P = 0.05). No effect of water deprivation or restriction on skin turgor was found. In the second experiment, water was withdrawn for 0 (control), 6, 12, 24, or 48 h. Plasma chloride concentration was increased after 6 h of water withdrawal, but did not rise further with longer withdrawal. If assessed at slaughter, chloride will thus mainly reflect the catching-to-slaughter interval. In contrast, plasma creatinine and hematocrit levels showed a numerical decrease after 6 h of water withdrawal, but rose again after prolonged withdrawal. Plasma creatinine values were significantly higher in 24-h-deprived birds than in 6-h-deprived birds (P < 0.01), allowing for discernment between water withdrawal during catching and transport from dehydration that had occurred on the farm. Blood sodium concentrations and plasma osmolality showed a steady increment between 0 and 24 h of water deprivation (P < 0.001 and P < 0.001 for both), and may thus be used to assess the combined effects of water deprivation on farm and during the catching-to-slaughter interval. These findings may form the basis of an on

  2. Formation and dehydration enthalpy of potassium hexaniobate

    SciTech Connect

    Sahu, Sulata K.; Boatner, Lynn A.; Navrotsky, Alexandra

    2016-09-15

    The formation energetics of hydrous and dehydrated potassium hexaniobates are investigated using high-temperature oxide melt solution calorimetry. The enthalpies of formation of K4Nb6O17 and K4Nb6O17•3H2O from oxides are (–864.42 ± 10.63) and (–899.32 ± 11.48) kJ/mol, respectively. The formation enthalpy of K4Nb6O17 from elements is (–7289.64 ± 12.50) kJ/mol, and of K4Nb6O17•3H2O is (–8181.94 ± 13.24) kJ/mol. The enthalpy of dehydration (ΔHdehy) for the reaction K4Nb6O173H2O (xl, 25 °C) = K4Nb6O17 (xl, 25 °C) + 3H2O (l, 25 °C) is endothermic and is 34.60 ± 7.56 kJ/mol. The ΔHdehy per mole of water, 11.53 ± 2.52 kJ/mol, indicates the water molecules in K4Nb6O17•3H2O are not just physically adsorbed, but loosely bonded in the K4Nb6O17 phase, presumably in specific interlayer sites. As a result, the loss of this water near 100 °C on heating is consistent with the weak bonding of water.

  3. Change in hydrogen bonding structures of a hydrogel with dehydration

    NASA Astrophysics Data System (ADS)

    Naohara, Ryo; Narita, Kentaro; Ikeda-Fukazawa, Tomoko

    2017-02-01

    To investigate the mechanisms of structural changes in polymer network and water during dehydration, X-ray diffraction of poly-N,N-dimethylacrylamide (PDMAA) hydrogels was measured. The variation process in the individual structures of water and PDMAA were analyzed by decomposition of the diffraction patterns to separate the respective contributions. The results show that the short-range structures of PDMAA expand during dehydration, whereas the network structure as a whole shrinks. The average length of the hydrogen bonds between water molecules increases with the process. The present results provide a direct evidence of the structural changes of water and polymer in the hydrogel during dehydration.

  4. Transient dehydration of lungs in tail-suspended rats

    NASA Technical Reports Server (NTRS)

    Hargens, A. R.; Steskal, J.; Morey-Holton, E. R.

    1985-01-01

    The fluid balance in the lungs of rats exposed to head-down tilt is examined. Six Munich-Wister rats were suspended for 7 days and 10 Sprague-Dawley rats for 14 days using the technique of Morey (1979). The water contents of the lungs of the suspended and a control group are calculated and compared. The data reveal that the two-days suspended rats had dehydrated lungs; however, the lungs of the 14-day suspended and control group rats were similar. It is noted that the dehydration in the 2-day suspended rats is caused by general dehydration not the head-tilt position.

  5. Effects of prior experience with dehydration and water on the time course of dehydration-induced drinking in weanling rats.

    PubMed

    Myers, K P; Hall, W G

    2001-04-01

    Although cellular dehydration increases oral responding and swallowing of orally infused water in rats as young as 2 days old, it is not until well after the time of weaning that dehydration stimulates immediate water-seeking and initiation of drinking in situations where the water source must be approached voluntarily. Recent work has shown that the goal-directed appetitive sequence for drinking-orienting, approaching, and initiating contact with water-matures much later than the more precocial oral licking and swallowing behaviors, and normally comes to be elicited by dehydration only after post-weaning experience with dry food. In the current experiments we evaluate some critical features of post-weaning experience with dehydration and drinking, and find that prior experience with initiating drinking while dehydrated, but not experience with dehydration nor water per se, alters the time course of water intake during a subsequent hydrational challenge. The effects of experience are manifested as an increased proportion of water consumed in the early portion of the test, rather than a general increase in total consumption. These findings are consistent with the interpretation that prior experience is necessary for the coordination of water-oriented appetitive behaviors that lead to the initiation and maintenance of drinking bouts, and provide further evidence for an associative learning account of the acquisition of dehydration-induced drinking.

  6. Renal tubular vasopressin receptors downregulated by dehydration

    SciTech Connect

    Steiner, M.; Phillips, M.I. )

    1988-03-01

    Receptors for arginine vasopressin (AVP) were characterized in tubular epithelial basolateral membranes (BL membranes) prepared from the kidneys of male Spraque-Dawley rats. Association of ({sup 3}H)AVP was rapid, reversible, and specific. Saturation studies revealed a single class of saturable binding sites with a maximal binding (B{sub max}) of 184 {plus minus} 15 fmol/mg protein. The V{sub 2} receptor antagonist was more than 3,700 times as effective in displacing ({sup 3}H)AVP than was the V{sub 1} antagonist. To investigate the physiological regulation of vasopressin receptors, the effects of elevated levels of circulating AVP on receptor characteristics were studied. Seventy-two-hour water deprivation significantly elevated plasma osmolality and caused an 11.5-fold increase in plasma (AVP). Scatchard analysis revealed a 38% decreased in the number of AVP receptors on the BL membranes from dehydrated animals. The high-affinity binding sites on the BL membranes fit the pharmacological profile for adenylate cyclase-linked vasopressin receptors (V{sub 2}), which mediate the antidiuretic action of the hormone. The authors conclude that physiologically elevated levels of AVP can downregulate vasopressin receptors in the kidney.

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

    PubMed Central

    2014-01-01

    Background 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. Methods 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). Results 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 < 0.0001) in the trauma group. Median CDS was 3 (range 0–8) within the dehydration group and 0 in the comparison group (p < 0.0001). The following parameters were statistically significant (p < 0.05) between the comparison group and the 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). Conclusion Although serum bicarbonate is not the gold standard for dehydration, this study provides

  8. Voluntary dehydration and cognitive performance in trained college athletes.

    PubMed

    D'anci, Kristen E; Vibhakar, Arjun; Kanter, Jordan H; Mahoney, Caroline R; Taylor, Holly A

    2009-08-01

    Cognitive and mood decrements resulting from mild dehydration and glucose consumption were studied. Men and women (total N = 54; M age = 19.8 yr., SD = 1.2) were recruited from college athletic teams. Euhydration or dehydration was achieved by athletes completing team practices with or without water replacement. Dehydration was associated with higher thirst and negative mood ratings as well as better Digit Span performance. Participants showed better Vigilance Attention with euhydration. Hydration status and athlete's sex interacted with performance on Choice Reaction Time and Vigilance Attention. In a second study, half of the athletes received glucose prior to cognitive testing. Results for negative mood and thirst ratings were similar, but for cognitive performance the results were mixed. Effects of glucose on cognition were independent of dehydration.

  9. Hospital Admissions for Malnutrition and Dehydration in Patients With Dementia.

    PubMed

    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.

  10. NOVEL POLYMERIC MEMBRANE FOR DEHYDRATION OF ORGANIC SOLVENTS

    EPA Science Inventory

    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...

  11. Effects of dehydration on performance in man: Annotated bibliography

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.

    1973-01-01

    A compilation of studies on the effect of dehydration on human performance and related physiological mechanisms. The annotations are listed in alphabetical order by first author and cover material through June 1973.

  12. Dehydration and crystallization kinetics of zirconia-yttria gels

    SciTech Connect

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

    1995-02-01

    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.

  13. Survey of quality indicators in commercial dehydrated fruits.

    PubMed

    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.

  14. Neuropsychological Performance, Postural Stability, and Symptoms After Dehydration

    PubMed Central

    Patel, Akshay V; Mihalik, Jason P; Notebaert, Andrew J; Guskiewicz, Kevin M; Prentice, William E

    2007-01-01

    Context: Dehydration and concussion are common in athletic performance. Some experts have speculated that dehydration may negatively influence performance on tests commonly used for concussion assessment. Objective: To determine how the signs and symptoms, neuropsychological performance, and postural stability are affected by dehydration. Design: Repeated-measures design assessing subjects in the euhydrated and dehydrated conditions. Setting: Sports Medicine Research Laboratory. Patients or Other Participants: Twenty-four healthy, male recreational athletes participated in the study. Intervention(s): Subjects participated in 2 counterbalanced sessions (euhydrated and dehydrated) separated by at least 7 days. Subjects were dehydrated using fluid restriction and an exercise task. No direct intervention was provided for the euhydrated condition. Main Outcome Measure(s): We used the Standardized Assessment of Concussion to test mental status, the Automated Neuropsychological Assessment Metrics (ANAM) to evaluate neuropsychological performance, the NeuroCom Sensory Organization Test and Balance Error Scoring System to test postural stability, the Graded Symptom Checklist to assess symptom presence and severity in our participants, and urine specific gravity and body mass to determine hydration status. Results: No differences were noted for the Standardized Assessment of Concussion, total Balance Error Scoring System errors, composite Sensory Organization Test, and composite ANAM scores between conditions. Subjects in the dehydrated condition had significant deterioration in visual memory (t23 = 2.130, P < .001) and fatigue measures (t23 = −7.880, P < .001) as assessed by ANAM. The dehydrated condition resulted in subjects reporting a significantly higher number (t23 = −8.585, P < .001) and severity (t23 = −7.673, P < .001) of symptoms than the euhydrated subjects on the Graded Symptom Checklist. Conclusions: Our results suggest that moderate dehydration (−2.5

  15. [Use of zinc-containing dehydrating fixatives for neurohistological studies].

    PubMed

    Korzhevskiĭ, D E; Grigor'ev, I P; Otellin, V A

    2006-01-01

    The suitability of zinc-containing dehydrating fixatives for neurohistological study of paraffin sections using Nissl staining and immunocytochemical techniques was examined. It was found that zinc-containing dehydrating fixatives (zinc-ethanol-formaldehyde and zinc-acetone-isopropanol-formaldehyde) had a capacity for good preservation of both structure and antigenic properties of the nervous tissue and could be recommended for application in neurohistological studies.

  16. External Validation and Comparison of Three Pediatric Clinical Dehydration Scales

    PubMed Central

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

    2014-01-01

    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. PMID:24788134

  17. Control of Transient Slip Weakening During Gypsum Dehydration

    NASA Astrophysics Data System (ADS)

    Leclere, H.; Faulkner, D.; Wheeler, J.; Mariani, E.

    2015-12-01

    The understanding of fault mechanics is of first order importance to unravel earthquake triggering. Among the parameters influencing fault reactivation and earthquake triggering, the influence of pore-fluid pressure and friction on stability of fault zones have been a focus of recent work based on geological, geophysical and experimental analyses. Here, the effects of dehydration reactions on hydraulic and mechanical properties of rock are analysed to better understand the conditions required to trigger earthquakes. Triaxial experiments are conducted using gypsum and a direct shear sample assembly that allows a constant normal stress to be applied and permeability to be measured during sliding. The evolutions of shear stress, pore-fluid pressure and permeability are continuously measured throughout the experiment until dehydration reaction reached completion. Tests are conducted with a temperature ramp from 70 to 150 °C and with different effective confining pressures (50, 100 and 150 MPa) and velocities (0.1 and 0.4 μm.s-1). Results show that gypsum dehydration induces transient stable slip weakening that is controlled by pore-fluid pressure and permeability evolutions followed by unstable slip on fully dehydrated product.The evolution of microstructures and mineralogy during the experiment are inferred from SEM and XRD analyses of deformed samples collected at different key stages during repeated tests. The microstructural analysis shows clear evidence of dehydration reactions related to the development of S-C-C' structures where dehydration product is preferentially localized along shear and schistosity planes. A conceptual model is then proposed to explain transient slip weakening during dehydration reactions incorporating the key role played by permeability, and to provide a framework to define the conditions required to trigger unstable events during dehydration reactions.

  18. Seawater drinking restores water balance in dehydrated harp seals.

    PubMed

    How, Ole-Jakob; Nordøy, Erling S

    2007-07-01

    The purpose of this study was to answer the question of whether dehydrated harp seals (Phoca groenlandica) are able to obtain a net gain of water from the intake of seawater. Following 24 h of fasting, three subadult female harp seals were dehydrated by intravenous administration of the osmotic diuretic, mannitol. After another 24 h of fasting, the seals were given 1,000 ml seawater via a stomach tube. Urine and blood were collected for measurement of osmolality and osmolytes, while total body water (TBW) was determined by injections of tritiated water. In all seals, the maximum urinary concentrations of Na(+) and Cl(-) were higher than in seawater, reaching 540 and 620 mM, respectively, compared to 444 and 535 mM in seawater. In another experiment, the seals were given ad lib access to seawater for 48 h after mannitol-induced hyper-osmotic dehydration. In animals without access to seawater, the mean blood osmolality increased from 331 to 363 mOsm kg(-1) during dehydration. In contrast, the blood osmolality, hematocrit and TBW returned to normal when the seals were permitted ad lib access to seawater after dehydration. In conclusion, this study shows that harp seals have the capacity to gain net water from mariposa (voluntarily drinking seawater) and are able to restore water balance after profound dehydration by drinking seawater.

  19. Kinetics of volatile extraction from carbonaceous chondrites: Dehydration of talc

    NASA Technical Reports Server (NTRS)

    Bose, Kunal; Ganguly, Jibamitra

    1991-01-01

    Carbonaceous chondrites are believed to be the primary constituents of near-Earth asteroids and Phobos and Deimos, and are potential resources of fuels that may be exploited for future planetary missions. Calculations of equilibrium phase relations suggest that talc (Ta) and antigorite (Ant) are likely to be the major hydrous phases in the C1 and C2 meteorites (Ganguly and Saxena, 1989), which constitute the most volatile rich classes of carbonaceous chondrites. The dehydration kinetics of talc are studied as a function of temperature, grain size, composition and fluid fugacity, as part of a systematic study of the reaction kinetics of the volatile bearing phases that are either known or likely to be present in carbonaceous chondrites. The dehydration kinetics were investigated at 1 bar, 775 to 875 C by monitoring the in-situ weight loss as a function of time of a natural talc. The talc platelets had a dimension of 0.8 to 1 micron. The run durations varied from 233.3 hours at 775 C (48 percent dehydration) to 20.8 hours at 875 C (80 pct. dehydration). The results can be adequately represented by a given rate equation. Theoretical analysis suggests that the reduction in the concentration of H2O in the environment of dehydrating talc, as would be encountered in processing chondritic materials, will have negligible effect on the rate of dehydration, unless there is a change of reaction mechanism owing to the presence of other volatile species.

  20. Fructokinase activity mediates dehydration-induced renal injury.

    PubMed

    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.

  1. Traditional Male Circumcision: Ways to Prevent Deaths Due to Dehydration.

    PubMed

    Douglas, Mbuyiselo; Maluleke, Thelmah Xavela

    2016-02-01

    Deaths of initiates occurring in the circumcision initiation schools are preventable. Current studies list dehydration as one of the underlying causes of deaths among traditional male circumcision initiates in the Eastern Cape, a province in South Africa, but ways to prevent dehydration in the initiation schools have not been adequately explored. The goals of this study were to (a) explore the underlying determinants of dehydration among initiates aged from 12 to 18 years in the traditional male circumcision initiation schools and (b) determine knowledge of participants on the actions to be taken to prevent dehydration. The study was conducted at Libode, a rural area falling under Nyandeni municipality. A simple random sampling was used to select three focus group discussions with 36 circumcised boys. A purposive sampling was used to select 10 key informants who were matured and experienced people with knowledge of traditional practices and responsible positions in the communities. The research findings indicate that the practice has been neglected to inexperienced, unskillful, and abusive traditional attendants. The overall themes collated included traditional reasons for water restriction, imbalanced food nutrients given to initiates, poor environmental conditions in the initiation hut, and actions that should be taken to prevent dehydration. This article concludes with discussion and recommendation of ways to prevent dehydration of initiates in the form of a comprehensive circumcision health promotion program.

  2. Ice Cloud Formation and Dehydration in the Tropical Tropopause Layer

    NASA Technical Reports Server (NTRS)

    Jensen, Eric; Gore, Warren J. (Technical Monitor)

    2002-01-01

    Stratospheric water vapor is important not only for its greenhouse forcing, but also because it plays a significant role in stratospheric chemistry. Several recent studies have focused on the potential for dehydration due to ice cloud formation in air rising slowly through the tropical tropopause layer (TTL). Holton and Gettelman showed that temperature variations associated with horizontal transport of air in the TTL can drive ice cloud formation and dehydration, and Gettelman et al. recently examined the cloud formation and dehydration along kinematic trajectories using simple assumptions about the cloud properties. In this study, a Lagrangian, one-dimensional cloud model has been used to further investigate cloud formation and dehydration as air is transported horizontally and vertically through the TTL. Time-height curtains of temperature are extracted from meteorological analyses. The model tracks the growth, advection, and sedimentation of individual cloud particles. The regional distribution of clouds simulated in the model is comparable to the subvisible cirrus distribution indicated by SAGE II. The simulated cloud properties and cloud frequencies depend strongly on the assumed supersaturation threshold for ice nucleation. The clouds typically do not dehydrate the air along trajectories down to the temperature minimum saturation mixing ratio. Rather the water vapor mixing ratio crossing the tropopause along trajectories is 10-50% larger than the saturation mixing ratio. I will also discuss the impacts of Kelvin waves and gravity waves on cloud properties and dehydration efficiency. These simulations can be used to determine whether observed lower stratospheric water vapor mixing ratios can be explained by dehydration associated with in situ TTL cloud formation alone.

  3. Dehydration affects brain structure and function in healthy adolescents.

    PubMed

    Kempton, Matthew J; Ettinger, Ulrich; Foster, Russell; Williams, Steven C R; Calvert, Gemma A; Hampshire, Adam; Zelaya, Fernando O; O'Gorman, Ruth L; McMorris, Terry; Owen, Adrian M; Smith, Marcus S

    2011-01-01

    It was recently observed that dehydration causes shrinkage of brain tissue and an associated increase in ventricular volume. Negative effects of dehydration on cognitive performance have been shown in some but not all studies, and it has also been reported that an increased perceived effort may be required following dehydration. However, the effects of dehydration on brain function are unknown. We investigated this question using functional magnetic resonance imaging (fMRI) in 10 healthy adolescents (mean age = 16.8, five females). Each subject completed a thermal exercise protocol and nonthermal exercise control condition in a cross-over repeated measures design. Subjects lost more weight via perspiration in the thermal exercise versus the control condition (P < 0.0001), and lateral ventricle enlargement correlated with the reduction in body mass (r = 0.77, P = 0.01). Dehydration following the thermal exercise protocol led to a significantly stronger increase in fronto-parietal blood-oxygen-level-dependent (BOLD) response during an executive function task (Tower of London) than the control condition, whereas cerebral perfusion during rest was not affected. The increase in BOLD response after dehydration was not paralleled by a change in cognitive performance, suggesting an inefficient use of brain metabolic activity following dehydration. This pattern indicates that participants exerted a higher level of neuronal activity in order to achieve the same performance level. Given the limited availability of brain metabolic resources, these findings suggest that prolonged states of reduced water intake may adversely impact executive functions such as planning and visuo-spatial processing.

  4. Microcrystalline hexagonal tungsten bronze. 2. Dehydration dynamics.

    PubMed

    Luca, Vittorio; Griffith, Christopher S; Hanna, John V

    2009-07-06

    Low-temperature (25-600 degrees C) thermal transformations have been studied for hydrothermally prepared, microcrystalline hexagonal tungsten bronze (HTB) phases A(x)WO(3+x/2).zH(2)O as a function of temperature, where A is an exchangeable cation (in this case Na(+) or Cs(+)) located in hexagonal structural tunnels. Thermal treatment of the as-prepared sodium- and cesium-exchanged phases in air were monitored using a conventional laboratory-based X-ray diffractometer, while thermal transformations in vacuum were studied using synchrotron X-ray and neutron diffraction. Concurrent thermogravimetric, diffuse reflectance infrared (DRIFT), and (23)Na and (133)Cs magic angle spinning (MAS) NMR spectroscopic studies have also been undertaken. For the cesium variant, cell volume contraction occurred from room temperature to about 350 degrees C, the regime in which water was "squeezed" out of tunnel sites. This was followed by a lattice expansion in the 350-600 degrees C temperature range. Over the entire temperature range, a net thermal contraction was observed, and this was the result of an anisotropic change in the cell dimensions which included a shortening of the A-O2 bond length. These changes explain why Cs(+) ions are locked into tunnel positions at temperatures as low as 400 degrees C, subsequently inducing a significant reduction in Cs(+) extractability under low pH (nitric acid) conditions. The changing Cs(+) speciation as detected by (133)Cs MAS NMR showed a condensation from multiple Cs sites, presumably associated with differing modes of Cs(+) hydration in the tunnels, to a single Cs(+) environment upon thermal transformation and water removal. While similar lattice contraction was observed for the as-prepared sodium variant, the smaller radius of Na(+) caused it to be relatively easily removed with acid in comparison to the Cs(+) variant. From (23)Na MAS NMR studies of the parent material, complex Na(+) speciation was observed with dehydrated and various

  5. Dehydration and Cognition in Geriatrics: A Hydromolecular Hypothesis

    PubMed Central

    Sfera, Adonis; Cummings, Michael; Osorio, Carolina

    2016-01-01

    Dehydration is one of the ten most frequent diagnoses responsible for the hospital admission of elderly in the United States. It is associated with increased mortality, morbidity and an estimated cost of 1.14 billion per year (Xiao et al., 2004; Schlanger et al., 2010; Pretorius et al., 2013; Frangeskou et al., 2015). Older individuals are predisposed to dehydration encephalopathy as a result of decreased total body water (TBW) and diminished sensation of thirst. We hypothesize that thirst blunting in older individuals is the result of a defective microRNA-6842-3p failing to silence the expression of the vesicular GABA transporters (VGAT) and alpha 7 cholinergic nicotinic receptors in the subfornical organ (SFO) of the hypothalamus. We hypothesize further that resultant dehydration facilitates protein misfolding and aggregation, predisposing to neurocognitive disorders. We completed a search of predicted microRNA targets, utilizing the public domain tool miRDB and found that microRNA-6842-3p modulates the SLC6A1 and CHRNA7 genes both of which were previously hypothesized to inhibit the thirst sensation by their action on SFO. The primary aim of this article is to answer two questions: Can prevention and correction of dehydration in elderly lower age-related cognitive deterioration? Can exosomal miR-6842 in the peripheral blood predict dehydration encephalopathy in elderly? PMID:27252943

  6. Urinary caffeine after coffee consumption and heat dehydration.

    PubMed

    Chambaz, A; Meirim, I; Décombaz, J

    2001-07-01

    This study evaluated the effect of heat-induced dehydration on urinary caffeine excretion after the consumption of a strong coffee solution. Following ingestion of coffee (caffeine 4.9+/-0.1 [SE] mg/kg, 3-4 cups), ten healthy males were intermittently exposed to heat in a sauna until they had lost 2.9 % of lean mass. On a separate occasion, they consumed the same amount of coffee but remained quiet and euhydrated (control). Urine flow was reduced 7-fold in dehydration. At these low excretion rates (< 30 ml/h), caffeine concentration was negatively correlated with flow. Peak urinary caffeine (Cmax) was 7.6 +/- 0.4 (SE) microg/ml in dehydration and 7.1 +/- 0.2 microg/ml in the control (p > 0.05). Compared with the control, dehydration delayed Cmax by 1 hour, maintained higher saliva caffeine concentration (6.1 vs 5.2 microg/ml, p < 0.05) and a lower saliva paraxanthine/caffeine ratio (p < 0.001). The 24h-recovery of caffeine in urine was reduced (1.2 vs 2.8% of dose, p < 0.001), however at least 2.6% of dose were lost in sweat. These results suggest that the rise in circulating caffeine due to delayed metabolic clearance was partly opposed by a sizeable elimination in sweat. Therefore, heat dehydration did not lead to higher concentration of caffeine in urine after coffee ingestion.

  7. Geothermal vegetable dehydration at Brady`s Hot Springs, Nevada

    SciTech Connect

    Lund, J.W.

    1994-07-01

    This article describes the utilization of the Brady`s Springs geothermal resource for heat generation used in the food dehydration process. This geothermal system is located in the Forty-Mile Desert area of Nevada. Geothermal Food Processors, Inc. of Reno, Nevada started construction of the geothermal vegetable dehydration plant in 1978, and the plant started operations in 1979. The industrial process of vegetable dehydration at the plant is described. In July of 1992, the Brady`s Springs geothermal system began being used for power generation by the Brady`s Hot Springs geothermal power plant, operated by Oxbow Power Services, Inc. As a result, the water levels in the food processing plant wells have dropped below usable levels and the geothermal brine is now being supplied by the Oxbow power plant.

  8. Isothermal dehydration of thin films of water and sugar solutions

    SciTech Connect

    Heyd, R.; Rampino, A.; Bellich, B.; Elisei, E.; Cesàro, A.; Saboungi, M.-L.

    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.

  9. Effect of experimental and sample factors on dehydration kinetics of mildronate dihydrate: mechanism of dehydration and determination of kinetic parameters.

    PubMed

    Bērziņš, Agris; Actiņš, Andris

    2014-06-01

    The dehydration kinetics of mildronate dihydrate [3-(1,1,1-trimethylhydrazin-1-ium-2-yl)propionate dihydrate] was analyzed in isothermal and nonisothermal modes. The particle size, sample preparation and storage, sample weight, nitrogen flow rate, relative humidity, and sample history were varied in order to evaluate the effect of these factors and to more accurately interpret the data obtained from such analysis. It was determined that comparable kinetic parameters can be obtained in both isothermal and nonisothermal mode. However, dehydration activation energy values obtained in nonisothermal mode showed variation with conversion degree because of different rate-limiting step energy at higher temperature. Moreover, carrying out experiments in this mode required consideration of additional experimental complications. Our study of the different sample and experimental factor effect revealed information about changes of the dehydration rate-limiting step energy, variable contribution from different rate limiting steps, as well as clarified the dehydration mechanism. Procedures for convenient and fast determination of dehydration kinetic parameters were offered.

  10. Dehydration decreases saliva antimicrobial proteins important for mucosal immunity.

    PubMed

    Fortes, Matthew B; Diment, Bethany C; Di Felice, Umberto; Walsh, Neil P

    2012-10-01

    The aim of the study was to investigate the effect of exercise-induced dehydration and subsequent overnight fluid restriction on saliva antimicrobial proteins important for host defence (secretory IgA (SIgA), α-amylase, and lysozyme). On two randomized occasions, 13 participants exercised in the heat, either without fluid intake to evoke progressive body mass losses (BML) of 1%, 2%, and 3% with subsequent overnight fluid restriction until 0800 h in the following morning (DEH) or with fluids to offset losses (CON). Participants in the DEH trial rehydrated from 0800 h until 1100 h on day 2. BML, plasma osmolality (Posm), and urine specific gravity (USG) were assessed as hydration indices. Unstimulated saliva samples were assessed for flow rate (SFR), SIgA, α-amylase, and lysozyme concentrations. Posm and USG increased during dehydration and remained elevated after overnight fluid restriction (BML = 3.5% ± 0.3%, Posm = 297 ± 6 mosmol·kg⁻¹, and USG = 1.026 ± 0.002; P < 0.001). Dehydration decreased SFR (67% at 3% BML, 70% at 0800 h; P < 0.01) and increased SIgA concentration, with no effect on SIgA secretion rate. SFR and SIgA responses remained unchanged in the CON trial. Dehydration did not affect α-amylase or lysozyme concentration but decreased secretion rates of α-amylase (44% at 3% BML, 78% at 0800 h; P < 0.01) and lysozyme (46% at 3% BML, 61% at 0800 h; P < 0.01), which were lower than in CON at these time points (P < 0.05). Rehydration returned all saliva variables to baseline. In conclusion, modest dehydration (~3% BML) decreased SFR, α-amylase, and lysozyme secretion rates. Whether the observed magnitude of decrease in saliva AMPs during dehydration compromises host defence remains to be shown.

  11. Ice Cloud Formation and Dehydration in the Tropical Tropopause Layer

    NASA Technical Reports Server (NTRS)

    Jensen, Eric; Pfister, Leonhard; Gore, Warren J. (Technical Monitor)

    2002-01-01

    Stratospheric water vapor is important not only for its greenhouse forcing, but also because it plays a significant role in stratospheric chemistry. several recent studies have focused on the potential for dehydration due to ice cloud formation in air rising slowly through the tropical tropopause layer. Holton and Gettelman showed that temperature variations associated with horizontal transport of air in the tropopause layer can drive ice cloud formation and dehydration, and Gettelman et al. recently examined the cloud formation and dehydration along kinematic trajectories using simple assumptions about the cloud properties. In this study, we use a Lagrangian, one-dimensional cloud model to further investigate cloud formation and dehydration as air is transported horizontally and vertically through the tropical tropopause layer. Time-height curtains of temperature are extracted from meteorological analyses. The model tracks the growth and sedimentation of individual cloud particles. The regional distribution of clouds simulated in the model is comparable to the subvisible cirrus distribution indicated by SAGE II. The simulated cloud properties depend strongly on the assumed ice supersaturation threshold for ice nucleation. with effective nuclei present (low supersaturation threshold), ice number densities are high (0.1--10 cm(circumflex)-3), and ice crystals do not grow large enough to fall very far, resulting in limited dehydration. With higher supersaturation thresholds, ice number densities are much lower (less than 0.01 cm(circumflex)-3), and ice crystals grow large enough to fall substantially; however, supersaturated air often crosses the tropopause without cloud formation. The clouds typically do not dehydrate the air along trajectories down to the temperature minimum saturation mixing ratio. Rather the water vapor mixing ratio crossing the tropopause along trajectories is typically 10-50% larger than the saturation mixing ratio.

  12. Boria modified alumina probed by methanol dehydration and IR spectroscopy

    NASA Astrophysics Data System (ADS)

    de Farias, Andréa M. Duarte; Esteves, Angela M. Lavogade; Ziarelli, Fabio; Caldarelli, Stefano; Fraga, Marco A.; Appel, Lucia G.

    2004-04-01

    Al 2O 3·B 2O 3 catalysts were synthesized by co-precipitation and impregnation methods applying two calcination temperatures and boria loadings. Catalysts were analyzed by IR spectroscopy of pyridine and CO 2 adsorption and were evaluated in methanol dehydration. Results showed that boron addition to alumina causes a decrease of the number of basic and Lewis acid sites on alumina surface. It could also be observed an enhancement in acid strength of Lewis sites for impregnated samples. The results of methanol dehydration show that strong Brönsted sites are not formed on borate alumina.

  13. Ductile Deformation of Dehydrating Serpentinite Evidenced by Acoustic Signal Monitoring

    NASA Astrophysics Data System (ADS)

    Gasc, J.; Hilairet, N.; Wang, Y.; Schubnel, A. J.

    2012-12-01

    Serpentinite dehydration is believed to be responsible for triggering earthquakes at intermediate depths (i.e., 60-300 km) in subduction zones. Based on experimental results, some authors have proposed mechanisms that explain how brittle deformation can occur despite high pressure and temperature conditions [1]. However, reproducing microseismicity in the laboratory associated with the deformation of dehydrating serpentinite remains challenging. A recent study showed that, even for fast dehydration kinetics, ductile deformation could take place rather than brittle faulting in the sample [2]. This latter study was conducted in a multi-anvil apparatus without the ability to control differential stress during dehydration. We have since conducted controlled deformation experiments in the deformation-DIA (D-DIA) on natural serpentinite samples at sector 13 (GSECARS) of the APS. Monochromatic radiation was used with both a 2D MAR-CCD detector and a CCD camera to determine the stress and the strain of the sample during the deformation process [3]. In addition, an Acoustic Emission (AE) recording setup was used to monitor the microseismicity from the sample, using piezo-ceramic transducers glued on the basal truncation of the anvils. The use of six independent transducers allows locating the AEs and calculating the corresponding focal mechanisms. The samples were deformed at strain rates of 10-5-10-4 s-1 under confining pressures of 3-5 GPa. Dehydration was triggered during the deformation by heating the samples at rates ranging from 5 to 60 K/min. Before the onset of the dehydration, X-ray diffraction data showed that the serpentinite sustained ~1 GPa of stress which plummeted when dehydration occurred. Although AEs were recorded during the compression and decompression stages, no AEs ever accompanied this stress drop, suggesting ductile deformation of the samples. Hence, unlike many previous studies, no evidence for fluid embrittlement and anticrack generation was found

  14. EPR study on gamma-irradiated fruits dehydrated via osmosis

    NASA Astrophysics Data System (ADS)

    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.

  15. Increased efficiency using the encapsulation-dehydration cryopreservation technique

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arabidopsis thaliana shoot tips were successfully cryopreserved using encapsulation-dehydration cryopreservation methods. Between one and seven shoot tips were encapsulated within 4 mm calcium-alginate beads. Beads were formed in the presence of 2 M glycerol+0.4M sucrose. The time required to mak...

  16. Diagnosis of pneumonia in children with dehydrating diarrhoea.

    PubMed

    Saha, Debasish; Ronan, Anne; Khan, Wasif Ali; Salam, Mohammed Abdus

    2014-03-01

    The World Health Organization (WHO) guidelines for diagnosis of pneumonia are based on the history of cough or difficult breathing and age-adjusted respiration rates. Metabolic acidosis associated with dehydrating diarrhoea also influences the respiration rate. Two hundred and four children, aged 2 to 59 months, with dehydrating diarrhoea and a history of cough and/or fast breathing, were enrolled in a prospective study. Pneumonia diagnoses were made on enrollment and again 6 hours post-enrollment (after initial rehydration), using the WHO guidelines. These were compared with investigators' clinical diagnosis based on history and findings of physical examination and a chest x-ray at the same time points. Using the WHO guidelines, 149/152 (98%) infants in the 2-11 months age-group and 38/40 (95%) children in the 12-59 months age-group were diagnosed to have pneumonia on enrollment, which dropped to 107 (70%) and 30 (75%) respectively at 6 hours post-enrollment. The specificity of the WHO guidelines for diagnosis of pneumonia was very low (6.9%) at enrollment but increased to 65.5% at 6 hours post-enrollment, after initial rehydration. The specificity of the WHO guidelines for diagnosis of pneumonia in young children is significantly reduced in dehydrating diarrhoea. For young children with dehydrating diarrhoea, rehydration, clinical and radiological assessments are useful in identifying those with true pneumonia.

  17. [Oral rehydration in newborns with dehydration caused by diarrhea].

    PubMed

    Mota-Hernández, F; Rillman-Pinagel, M L; Velásquez-Jones, L

    1990-08-01

    The clinical experience obtained while treating 43 dehydrated newborns due to diarrhea with oral rehydration solution (ORS) using the formula recommended by the World Health Organization is reported. Of the 43 patients, 26 were severely dehydrated (greater than equal to 10% of weight recovery once rehydrated). The averaged time need to correct the dehydration was 4.7 +/- 2.7 hours, with a average intake of ORS of 26.5 +/- 7.5 mL/kg/hour. Children who were being breastfed continued so during the rehydration period. Two of the patients were hospitalized for intravenous treatment, one was due to persistent vomiting during rehydration and probably due to sepsis, and the other due to necrosing enterocolitis. The oral rehydration therapy was successful in 95% of the newborns included in the study, which proved the method to be safe and adequate for the correction of dehydration due to diarrhea among these patients. Similar experiences are reported in Mexico as well as from other countries, which also suggest the use of this therapeutic procedure in children of this age.

  18. Mechanisms by Which Dehydration May Lead to Chronic Kidney Disease.

    PubMed

    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.

  19. DEHYDRATION OF ALCOHOLS VIA PERVAPORATION USING A NOVEL HYDROHILIC MEMBRANE

    EPA Science Inventory

    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 suitable membrane system with high flux and high selectivity plays a criti...

  20. DEHYDRATION OF ALCOHOLS VIA PREVAPORATION USING A NOVEL HYDROPHILIC MEMBRANE

    EPA Science Inventory

    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 suitable membrane system with high flux and high selectivity plays a criti...

  1. Science Study Aids 1: Dehydration for Food Preservation.

    ERIC Educational Resources Information Center

    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…

  2. Diagnosis of Pneumonia in Children with Dehydrating Diarrhoea

    PubMed Central

    Ronan, Anne; Khan, Wasif Ali; Salam, Mohammed Abdus

    2014-01-01

    The World Health Organization (WHO) guidelines for diagnosis of pneumonia are based on the history of cough or difficult breathing and age-adjusted respiration rates. Metabolic acidosis associated with dehydrating diarrhoea also influences the respiration rate. Two hundred and four children, aged 2 to 59 months, with dehydrating diarrhoea and a history of cough and/or fast breathing, were enrolled in a prospective study. Pneumonia diagnoses were made on enrollment and again 6 hours post-enrollment (after initial rehydration), using the WHO guidelines. These were compared with investigators’ clinical diagnosis based on history and findings of physical examination and a chest x-ray at the same time points. Using the WHO guidelines, 149/152 (98%) infants in the 2-11 months age-group and 38/40 (95%) children in the 12-59 months age-group were diagnosed to have pneumonia on enrollment, which dropped to 107 (70%) and 30 (75%) respectively at 6 hours post-enrollment. The specificity of the WHO guidelines for diagnosis of pneumonia was very low (6.9%) at enrollment but increased to 65.5% at 6 hours post-enrollment, after initial rehydration. The specificity of the WHO guidelines for diagnosis of pneumonia in young children is significantly reduced in dehydrating diarrhoea. For young children with dehydrating diarrhoea, rehydration, clinical and radiological assessments are useful in identifying those with true pneumonia. PMID:24847588

  3. Study of wound dressing structure and hydration/dehydration properties

    NASA Astrophysics Data System (ADS)

    Lugão, A. B.; Machado, L. D. B.; Miranda, L. F.; Alvarez, M. R.; Rosiak, J. M.

    1998-06-01

    Hydrogels manufactured by radio-induced crosslinking and simultaneous sterilisation of hydrogels of PVP, PEG and agar, according to the Rosiak method, have many desirable properties for using as wound dressings. However, some properties need to be improved or better controlled. The membranes need to be strong enough to be freely used. Another important property to be controlled is the capacity of absorption of exudate and the kinetics of drying. Therefore, it was necessary to understand the role of main parameters (agar, PVP, PEG concentration and dose) in the structure of the net and in the hydration and dehydration properties. The structure of the membranes was studied by sol analysis and the hydrating/dehydrating properties were studied by isothermal thermogravimetric analysis. The gel content for all samples were always in agreement with expected values considering that only PVP undergoes crosslinking. The hydrating and dehydration results did not show variation with the tested parameters. It was concluded that the network was solely composed of crosslinked PVP plasticezed by the other compounds. The properties of hydration/dehydration is related rather to diffusion than to capillarity or osmose and to the chemical retention of water in the polymeric matrix.

  4. Compositional Constraints on Dehydration Embrittlement in Serpentinized Peridotite

    NASA Astrophysics Data System (ADS)

    Xia, G.; Zhang, J.; Green, H. W.

    2012-12-01

    Double seismic zones (DSZ) which have two parallel planes of seismicity separated by 15-40 km are a global feature of subduction zones in the 70-250 km depth range (Brudzinski et al., 2007). While the physical mechanism of lower plane seismicity is still controversial, the leading hypotheses currently are associated with dehydration of antigorite serpentine within the subducting mantle plate (Peacock, 2001; Jung et al., 2004). In this study, we are conducting high-pressure (1-3GPa), high-temperature (720-750 Celsius), deformation experiments on specimens of varying compositions of serpentine plus peridotite in our 4GPa Modified Griggs apparatus. Using samples composed of interlayered thin discs of antigorite and harzburgite, we find that dehydration embrittlement occurs down to less than ~30 vol % antigorite. Interlayered mineralogy was impractical at lower antigorite fractions so we prepared homogeneous mixtures of powders of the two rock types (35-75 μm grain-size) and "warm" pressed them to a coherent solid with little porosity. Subsequent deformation of these specimens extended the faulting regime to as little as ~8 vol % antigorite. In summary, we find that faulting occurs during dehydration in a wide range of serpentinized peridotite compositions but not during dehydration of nearly pure serpentinite nor nearly pure peridotite. We suggest that the lack of faulting in nearly pure peridotite is a consequence of too little H2O production and the lack of faulting in nearly pure serpentine is due to extensive crystal plasticity.

  5. Spatiotemporal evolution of dehydration reactions in subduction zones (Invited)

    NASA Astrophysics Data System (ADS)

    Padron-Navarta, J.

    2013-12-01

    Large-scale deep water cycling takes place through subduction zones in the Earth, making our planet unique in the solar system. This idiosyncrasy is the result of a precise but unknown balance between in-gassing and out-gassing fluxes of volatiles. Water is incorporated into hydrous minerals during seafloor alteration of the oceanic lithosphere. The cycling of volatiles is triggered by dehydration of these minerals that release fluids from the subducting slab to the mantle wedge and eventually to the crust or to the deep mantle. Whereas the loci of such reactions are reasonably well established, the mechanisms of fluid migration during dehydration reactions are still barely known. One of the challenges is that dehydration reactions are dynamic features evolving in time and space. Experimental data on low-temperature dehydration reactions (i.e. gypsum) and numerical models applied to middle-crust conditions point to a complex spatiotemporal evolution of the dehydration process. The extrapolation of these inferences to subduction settings has not yet been explored but it is essential to understand the dynamism of these settings. Here I propose an alternative approach to tackle this problem through the textural study of high-pressure terrains that experienced dehydration reactions. Spatiotemporal evolution of dehydration reactions should be recorded during mineral nucleation and growth through variations in time and space of the reaction rate. Insights on the fluid migration mechanism could be inferred therefore by noting changes in the texture of prograde assemblages. The dehydration of antigorite in serpentinite is a perfect candidate to test this approach as it releases a significant amount of fluid and produces a concomitant porosity. Unusual alternation of equilibrium and disequilibrium textures observed in Cerro del Almirez (Betic Cordillera, S Spain)[1, 2] attest for a complex fluid migration pattern for one of the most relevant reactions in subduction zones

  6. mPGES-1-derived PGE2 mediates dehydration natriuresis.

    PubMed

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

    2013-01-15

    PGE(2) 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 PGE(2) output and a 1.6-fold increase in PGE(2) 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 PGE(2) contributes to dehydration natriuresis likely via NO/cGMP.

  7. Self-Organizing Reactive Fluid Escape from Dehydrating Rocks

    NASA Astrophysics Data System (ADS)

    John, T.; Pluemper, O.; Podladchikov, Y.; Vrijmoed, J. C.; Scambelluri, M.

    2014-12-01

    Water escape from dehydrating rocks within the Earth's interior is a key process for long-term global water and element cycles, eg. at subduction zones a fluid escape mechanism must exist that prevents ocean water to be drained into the mantle. Existing fluid flow models require a priori physical assumptions (eg. preexisting porosity) and cannot resolve the evolution from initial fluid production to flow channelization. In order to develop a model of this evolution, we need to unravel natural laboratories that display the incipient dehydration stages and the micro- to macro-scale fluid escape route evolution. The Erro-Tobbio meta-serpentinites (Italy) provide a unique snapshot into these early dehydration stages, recording the breakdown of hydrous antigorite to anhydrous olivine plus fluid and the formation of an olivine-vein network. We find that dehydration, fluid pooling, and flow initiation are controlled by micro-scale compositional rock differences. Our model starts with a rock in which all water is stored in solid and any preexisting porosity is negligible (zero-porosity case). As the rock descents into the mantle increasing T will initiate dehydration reactions, dividing the rock continuously into a dry solid and a fluid-filled porosity. Spatially variable reaction progress results in dynamically evolving porosity/permeability and heterogeneous fluid-pore pressure distributions. Fluid-pressure gradient relaxation causes fluid flow and its thermodynamic feedback triggers reactions to progress, resulting in a self-amplifying process. Our new thermodynamic-mechanical model for reaction-porosity waves shows that fluid flow occurs solely in the reaction products and self-organizes into channelized fluid escape networks. This holds the key to formulating future quantitative models that address spatiotemporal processes such as the coupling between fluid release at depth and volcanic eruptions and the amounts of structurally bound water transferred into deep Earth.

  8. 40 CFR 407.50 - Applicability; description of the dehydrated potato products subcategory.

    Code of Federal Regulations, 2010 CFR

    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...

  9. 40 CFR 407.50 - Applicability; description of the dehydrated potato products subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 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...

  10. 40 CFR 407.50 - Applicability; description of the dehydrated potato products subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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...

  11. 40 CFR 407.50 - Applicability; description of the dehydrated potato products subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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...

  12. 40 CFR 407.50 - Applicability; description of the dehydrated potato products subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 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...

  13. Dehydration Injury in Germinating Soybean (Glycine max L. Merr.) Seeds 1

    PubMed Central

    Senaratna, Tissa; McKersie, Bryan D.

    1983-01-01

    The sensitivity of soybean (Glycine max L. Merr. cv Maple Arrow) seeds to dehydration changed during germination. Seeds were tolerant of dehydration to 10% moisture if dried at 6 hours of imbibition, but were susceptible to dehydration injury if dried at 36 hours of imbibition. Dehydration injury appeared as loss of germination, slower growth rates of isolated axes, hypocotyl and root curling, and altered membrane permeability. Increased electrolyte leakage due to dehydration treatment was observed only from isolated axes but not from cotyledons, suggesting that cotyledons are more tolerant of dehydration. The transition from a dehydration-tolerant to a dehydration-susceptible state coincided with radicle elongation. However, the prevention of cell elongation by osmotic treatment in polyethylene glycol (−6 bars) or imbibition in 20 micrograms per milliliter cycloheximide did not prevent the loss of dehydration tolerance suggesting that neither cell elongation nor cytoplasmic protein synthesis was responsible for the change in sensitivity of soybean seeds to dehydration. Furthermore, the rate of dehydration or rate of rehydration did not alter the response to the dehydration stress. PMID:16663056

  14. Slab crustal dehydration, melting and dynamics through time

    NASA Astrophysics Data System (ADS)

    van Hunen, Jeroen; Bouilhol, Pierre; Magni, Valentina; Maunder, Benjamin

    2015-04-01

    Melting subducted mafic crust is commonly assumed to be the main process leading to silicic melts with an adakitic signature, which may form Archaean granitoids and generate early continental crust. Alternatively, melting of the overriding lower mafic crust and near-Moho depth fractional crystallisation of mantle melts can form differentiated magmas with an adakitic signature. Previous work shows how only very young slabs melt through dehydration melting, or depict melting of dry eclogites via water addition from deeper slab dehydration. We quantify subduction dehydration and melting reactions in a warm subduction system using a thermo-mechanical subduction model with a thermodynamic database. We find that even young (hot) slabs dehydrate before reaching their solidus, which suppresses any slab dehydration melting and creates significant amounts of mantle wedge melting irrespective of slab age. Significant slab crust melting is only achieved in young slabs via water present melting if metamorphic fluids from the subducted mantle flux through the dry eclogites. These slab melts, however, are affected by massive mantle wedge melting and unlikely to participate in the overriding plate felsic magmatism, unlike the shallower, primitive mantle wedge melts. Understanding the overall flux of water carried by the descending slab mantle is therefore of prime importance. We thus inverstigated the deeper dehydration processes in subduction zones and implications for the water cycle throughout Earth's history. We estimate that presently ~26% of the global influx water is recycled into the mantle, and that deep water recycling was also significant (although less efficient, 2-13% at 2.8 Ga) in early Earth conditions, which has important implications for mantle dynamics and tectonic processes in the Early Earth. Alternatively, delamination and underplating of the mafic subducted crust would be a suitable mechanism to fit the geological record. We thus explore the conditions for

  15. Methods for dehydration of sugars and sugar alcohols

    DOEpatents

    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.

  16. The hydration/dehydration behavior of aspartame revisited.

    PubMed

    Guguta, C; Meekes, H; de Gelder, R

    2008-03-13

    Aspartame, l-aspartyl-l-phenylalanine methyl ester, has two hydrates (IA and IB), a hemi-hydrate (IIA) and an anhydrate (IIB). The hydration/dehydration behavior of aspartame was investigated using hot-humidity stage X-ray powder diffraction (XRPD) and molecular mechanics modeling in combination with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results of this study are compared to earlier studies on aspartame as described in literature. It is shown that earlier transition studies were hampered by incomplete conversions and wrong assignment of the forms. The combination of the techniques applied in this study now shows consistent results for aspartame and yields a clear conversion scheme for the hydration/dehydration behavior of the four forms.

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

    SciTech Connect

    Awad, Wael; Svensson Birkedal, Gabriel; Thunnissen, Marjolein M. G. M.; Mani, Katrin; Logan, Derek T.

    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.

  18. The physiological effects of dehydration caused by sweat loss. [athletes

    NASA Technical Reports Server (NTRS)

    Israel, S.

    1981-01-01

    The mechanisms of fluid loss in the human body while sweating due to physical exercise are discussed. Trained and untrained persons were examined and compared. Since sweat is hypotonous, a disruption in the hydrosalinic balance occurs; the consequences of this finding, also pertaining to the fluid and electrolytic substitution, are presented. Further explanations on the problem of dehydration refer to reactions of individual organ systems, to alterations in bodily capabilities as well as to questions relating to sex and age.

  19. Dehydration-induced porosity waves and episodic tremor and slip

    NASA Astrophysics Data System (ADS)

    Skarbek, Rob M.; Rempel, Alan W.

    2016-02-01

    Episodic tremor and slip (ETS) along the subduction interface takes place where there is abundant evidence for elevated, near-lithostatic pore pressures, at sufficiently great depths (30-45 km) that chemical dehydration reactions must act as their dominant source. We simulate fluid and heat flow while tracking the location of a vertically oriented, one-dimensional column of material as it subducts through the slow slip and tremor zone. The material in the column is transformed through a pressure-dependent and temperature-dependent dehydration reaction that we describe with a generalized nonlinear kinetic rate law. Column deformation is largely dominated by viscous creep, with a closure rate that depends linearly on porosity. This behavior causes the dehydration reaction to generate traveling porosity waves that transport increased fluid pressures within the slow slip region. To explore the possibility that the observed periodicity of slow slip and tremor in subduction zones can be explained by the migration of such porosity waves, we derive a dispersion relation that accurately describes our numerical results. We also obtain an expression for how the thickness of the dehydrating layer is expected to vary as a function of the parameters in the reaction rate law. Although the amplitudes of pore pressure perturbations rival those that are produced by known external forcings (e.g., tides or passing surface waves), our analysis suggests that given reasonable estimates of rock viscosity, permeabilities in the range 6.5×10-15 to 5×10-10 m2 are required for porosity wave trains to form at periods comparable to those of slow slip and tremor.

  20. 30. BUILDING NO. 527, DEHYDRATING PRESSES, LOOKING SOUTH. ALUMINUM NARROWGUAGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. BUILDING NO. 527, DEHYDRATING PRESSES, LOOKING SOUTH. ALUMINUM NARROW-GUAGE GONDOLA CAR IN LEFT BACKGROUND BROUGHT MOISTENED GUN COTTON FROM REST HOUSE (BUILDING NO. 320-B) IN CANS. (ONE OF THESE CANS IS ON UNLOADING PLATFORM RUNNING BESIDE PRESSES). CONTENTS OF CANS WERE UNLOADED INTO PRESSES BY HAND. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  1. Skeletal muscle water and electrolytes following prolonged dehydrating exercise.

    PubMed

    Mora-Rodríguez, R; Fernández-Elías, V E; Hamouti, N; Ortega, J F

    2015-06-01

    We studied if dehydrating exercise would reduce muscle water (H2Omuscle ) and affect muscle electrolyte concentrations. Vastus lateralis muscle biopsies were collected prior, immediately after, and 1 and 4 h after prolonged dehydrating exercise (150 min at 33 ± 1 °C, 25% ± 2% humidity) on nine endurance-trained cyclists (VO2max  = 54.4 ± 1.05 mL/kg/min). Plasma volume (PV) changes and fluid shifts between compartments (Cl(-) method) were measured. Exercise dehydrated subjects 4.7% ± 0.3% of body mass by losing 2.75 ± 0.15 L of water and reducing PV 18.4% ± 1% below pre-exercise values (P < 0.05). Right after exercise H2Omuscle remained at pre-exercise values (i.e., 398 ± 6 mL/100 g dw muscle(-1)) but declined 13% ± 2% (342 ± 12 mL/100 g dw muscle(-1); P < 0.05) after 1 h of supine rest. At that time, PV recovered toward pre-exercise levels. The Cl(-) method corroborated the shift of fluid between extracellular and intracellular compartments. After 4 h of recovery, PV returned to pre-exercise values; however, H2Omuscle remained reduced at the same level. Muscle Na(+) and K(+) increased (P < 0.05) in response to the H2Omuscle reductions. Our findings suggest that active skeletal muscle does not show a net loss of H2O during prolonged dehydrating exercise. However, during the first hour of recovery H2Omuscle decreases seemly to restore PV and thus cardiovascular stability.

  2. 28. BUILDING NO. 527, DEHYDRATING HOUSE, LOOKING SOUTH AT NORTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. BUILDING NO. 527, DEHYDRATING HOUSE, LOOKING SOUTH AT NORTH (REAR) ELEVATION OF PRELIMINARY SOLVENT RECOVERY WING. RAILS LEADING FROM DOORS CARRIED STANDARD GUAGE R.R. CARTS ONTO SMALL FLATCARS RIDING IN TRACKS IN FOREGROUND. FROM HERE THE CARS WERE TAKEN TO BUILDING NO. 533, SOLVENT RECOVERY. BUILDING NO. 540, LOADING DOCK (STORAGE FOR POWDER BUGGIES) IN BACKGROUND LEFT. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  3. Dehydration Influences Mood and Cognition: A Plausible Hypothesis?

    PubMed Central

    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

  4. When less means more: dehydration improves innate immunity in rattlesnakes.

    PubMed

    Brusch, George A; DeNardo, Dale F

    2017-04-12

    Immune function can vary based on availability of resources, and most studies of such influences have focused on the co-investment of energy into immune and other physiological functions. When energy resources are limited, trade-offs exist, which can compromise immunity for other functions. As with energy, water limitation can also alter various physiological processes, yet water has received little consideration for its role in possibly modulating immune functions. We examined the relationship between immunocompetence and hydration state using the western diamond-backed rattlesnake (Crotalus atrox). This species is known to undergo substantial seasonal fluctuations in water availability with extreme limitations during the hot, dry season. We collected blood samples from free-ranging C. atrox to compare osmolality and innate immune function (lysis, agglutination, bacterial growth inhibition) during the milder and relatively moister early spring season, the hot-dry season, and the hot-wet season. To isolate effects of dehydration from other possible seasonal influences, we complemented this field study with a laboratory study in which we withheld food and water from individually housed adult C. atrox for up to 16 weeks. We collected blood samples from each snake as it dehydrated and collected a final sample after the snake was given ad lib water at the end of the experiment. Our results demonstrate that C. atrox experience significant dehydration during the hot-dry season, and that, in general, innate immune function is highly correlated with osmolality, whether natural or artificially manipulated.

  5. Dehydration influences mood and cognition: a plausible hypothesis?

    PubMed

    Benton, David

    2011-05-01

    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.

  6. Inhibition of plasma vasopressin after drinking in dehydrated humans

    NASA Technical Reports Server (NTRS)

    Geelen, G.; Keil, L. C.; Kravik, S. E.; Wade, C. E.; Thrasher, T. N.; Barnes, P. R.; Pyka, G.; Nesvig, C.; Greenleaf, J. E.

    1984-01-01

    The effects of nonosmotic and nonvolumetric factors on vasopressin secretion in dehydrated humans has been investigated experimentally, before and after drinking. The subjects of the experiment were five adult men and three adult women weighing 69-77 kg. In order to determine the influence of nonosmotic and nonvolumetric factors on vasopressin secretion, measurements were obtained of the following blood hematological indices: serum Na(+) content; serum K(+) content; osmolality; and hemoglobin. Measurements of hematocrit, plasma arginine vasopressin (AVP), aldosterone, and renin activity were also obtained. It is found that dehydration increased mean serum Na(+) content, osmolality,and AVP. No significant changes were observed in renin activity, hemoglobin, hematocrit, or plasma volume, while plasma aldosterone increased from 11.1 ng/dl after dehydration to 15.6 ng/dl between 30 and 60 min after drinking. A rapid fall of AVP content following rehydration occurred in the absence of changes in the primary regulators of AVP osmolality and plasma volume, with no change in blood pressure. On the basis of the experimental results, it is suggested that oropharyngeal factors may be the mechanism, for the observed decrease in AVP following rehydration.

  7. Non-volcanic tremor and discontinuous slab dehydration

    NASA Astrophysics Data System (ADS)

    Fagereng, Åke; Diener, Johann F. A.

    2011-08-01

    Non-volcanic tremor is a recently discovered fault slip style occurring with remarkable regularity in space near the down-dip end of the locked zone on several subduction thrust interfaces. The physical mechanisms and the controls on the location of tremor have not yet been determined. We calculate the stable mineral assemblages and their water content in the subducting slab, and find that slab dehydration is not continuous, but rather restricted to a few reactions localised in pressure-temperature space. Along geothermal gradients applicable to Shikoku and Cascadia - where tremor has been relatively easy to detect - tremor locations correlate with discontinuous and localised voluminous water release from the breakdown of lawsonite and chlorite + glaucophane respectively. The shape of the pressure-temperature path for subducting slabs prevents fluid release at depths above and below where these dehydration reactions occur. We conclude that abundant tremor activity requires metamorphic conditions where localised dehydration occurs during subduction, and this may explain why tremor appears more abundant in some subduction zones than others.

  8. Inhibition of chloroplastic respiration by osmotic dehydration. [Spinacia oleracea L

    SciTech Connect

    Willeford, K.O.; Ahluwalia, K.J.K.; Gibbs, M. )

    1989-04-01

    The respiratory capacity of isolated spinach (Spinacia oleracea L.) chloroplasts, measured as the rate of {sup 14}CO{sub 2} evolved from the oxidative pentose phosphate cycle in darkened chloroplasts exogenously supplied with ({sup 14}C)glucose, was progressively diminished by escalating osmotic dehydration with betaine or sorbitol. Comparing the inhibitions of CO{sub 2} evolution generated by osmotic dehydration in chloroplasts given C-1 and C-6 labeled glucose, 54% and 84%, respectively, indicates that osmotic dehydration effects to a greater extent the recycling of the oxidative pentose phosphate intermediates, fructose-6P and glyceraldehyde-3P. Respiratory inhibition in the darkened chloroplast could be alleviated by addition of NH{sub 4}Cl (a stromal alkylating agent), iodoacetamide (an inhibitor of glyceraldehyde-3P dehydrogenase), or glycolate-2P (an inhibitor of phosphofructokinase). It is concluded that the site which primarily mediates respiratory inhibition in the darkened chloroplast occurs at the fructose 1,6-bisphosphatase/phosphofructokinase junction.

  9. Modelling of mass transfer kinetic in osmotic dehydration of kiwifruit

    NASA Astrophysics Data System (ADS)

    Jabrayili, Sharokh; Farzaneh, Vahid; Zare, Zahra; Bakhshabadi, Hamid; Babazadeh, Zahra; Mokhtarian, Mohsen; Carvalho, Isabel S.

    2016-04-01

    Osmotic dehydration characteristics of kiwifruit were predicted by different activation functions of an artificial neural network. Osmotic solution concentration (y1), osmotic solution temperature (y2), and immersion time (y3) were considered as the input parameters and solid gain value (x1) and water loss value (x2) were selected as the outlet parameters of the network. The result showed that logarithm sigmoid activation function has greater performance than tangent hyperbolic activation function for the prediction of osmotic dehydration parameters of kiwifruit. The minimum mean relative error for the solid gain and water loss parameters with one hidden layer and 19 nods were 0.00574 and 0.0062% for logarithm sigmoid activation function, respectively, which introduced logarithm sigmoid function as a more appropriate tool in the prediction of the osmotic dehydration of kiwifruit slices. As a result, it is concluded that this network is capable in the prediction of solid gain and water loss parameters (responses) with the correlation coefficient values of 0.986 and 0.989, respectively.

  10. Effects of dehydration and rehydration on thermoregulatory sweating in goats.

    PubMed Central

    Baker, M A

    1989-01-01

    1. Measurement of rectal temperature (Tr), sweat rate, respiratory frequency (f) and respiratory evaporation (Eresp) were made in one Nubian and four Alpine-Toggenberg goats while they stood for 90 min in a climate chamber at 40 degrees C ambient temperature (Ta). The animals were studied when they were hydrated, when they had been dehydrated by 48 h water deprivation, and when they were rehydrated by voluntary drinking of water or saline or by intraruminal water administration. Plasma osmolality (Posm), plasma protein concentration (PP) and haematocrit (Hct) were measured before every experiment and before and after voluntary drinking. 2. Hydrated animals increased evaporation by panting and sweating during heat exposure and Tr rose about 1 degree C. The rate of sweating was as high or higher than Eresp. Dehydrated animals had lower sweat rates and higher Tr than hydrated animals, but f and Eresp were the same in hydrated and dehydrated animals. 3. When dehydrated goats were allowed to drink after 60 min of heat exposure, sweating began abruptly within 3 min of the start of drinking in every animal whether water or saline was drunk. Sweat rate returned to hydrated levels or higher before any change occurred in Posm, PP or Hct. Respiratory frequency was higher after drinking than in dehydrated animals which were not allowed to drink. 4. When water was administered by rumen tube after 60 min of heat exposure, sweating in the Nubian occurred with a short latency, similar to the onset after drinking. In the other four animals, sweating onset occurred on average at 13 min 42 s after intraruminal water administration. 5. It is concluded that sweating is a significant avenue of evaporative heat loss in these goats when they are hydrated and exposed to high Ta. Sweat rate is markedly reduced after water deprivation but returns to hydrated levels within 3 min after the start of drinking. The rapid recovery of sweating after voluntary drinking is not initiated by changes in

  11. Gunion - Nevada`s most innovative geothermal food dehydration facility

    SciTech Connect

    Trexler, D.T.; Taylan, G.; Stewart, M.B.; Baker, S.

    1995-12-31

    The Gunion (garlic and onion) dehydration plant, owned and operated by Integrated Ingredients, a Division of Burns Philp Food, Incorporated, uses geothermal fluids at a temperature of 306{degrees}F to dehydrate 50 to 70-thousand pounds per day of garlic and onions. The geothermal fluids are provided by Empire Farms, who has the rights for development of the resource and is the lease holder of fee land known as the Kosmos Lease. The San Emidio KGRA is located in northern Washoe County, 90 miles north-northeast of Reno, Nevada and 20 miles south of Gerlach, Nevada. Geothermal fluids exit the plant at 242{degrees}F and are piped to an injection well located 3,000 feet south-southwest of the plant. The plant location was selected not only for the geothermal resource, but also for the area`s low relative humidity. Currently, 1100-1200 gpm of geothermal fluids, at an inlet temperature of 302{degrees}F, are sufficient to provide the dryer line with ample BTU`s. Three geothermal wells drilled to depths ranging from 493 to 1817 feet produce fluids ranging in temperature from 266 to 306{degrees}F. One well can easily provide the heat required by the dryer line and will be capable of providing heat for a planned three-fold expansion of the facility. The remaining two wells are used as backup, or may be used for other applications such as soil sterilization. The fluid exiting the plant at 242{degrees}F may be cascaded and used for greenhouses and soil warming in the future. Geothermal heat is also used to dehumidify onions placed in the cold storage facility. The dehydration process takes 5-6 hours to dry the product to a 4.5% moisture content. The dried product is then milled to various sizes from powder to granules. The dehydration plant operates 24 hours/day 7 days a week. Currently 80 people are employed full-time at the plant. The dehydrated onion and garlic are used in condiments, soups, sauces and salad dressing.

  12. Analysis of Dehydration and Strength in Elite Badminton Players

    PubMed Central

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

    2012-01-01

    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. PMID:22666396

  13. Slab dehydration recorded in subducted serpentine sea-mount

    NASA Astrophysics Data System (ADS)

    Okamoto, K.; Fukumura, S.; Ishimori, C.; Jung, H.

    2014-12-01

    It has been considered that there is a correlation between the double seismic zones and metamorphic dehydration reaction in deep slab. The lower seismic plane of the double seismic zone is considered to be located on the 600 oC isotherm in the subducting lithosphere. Antigorite terminal reaction is highly temperature sensitive around 600 oC. Therefore it has been proposed that the oceanic lithosphere was hydrated forming serpentine prior to subduction, then serpentine was decomposed to release fluid causing dehydration embrittlement in the slab. In order to unravel relation between dehydration and seismic deformation, we have investigated dehydration process of natural metamorphic rocks recording very cold geothermal history in the crust and lithosphere in the slab. Metamorphic olivine after antigorite has been described in Italian Alps and also from the Mt. Shiraga, Japan [1]. However, the olivine was formed with talc and fluid by antigorite breakdown reaction in pressures lower than 1.5 GPa. Spinifex olivine with opx in the Cerro del Almirez [2], is the product at pressures (P > 1.5 GPa) relevant to the lower seismic plane beneath Northeast Japan. It clearly indicates the presence of large amount of water facilitate crystallization of elongated olivine with opx. It is also supported by LPO pattern of olivines determined by EBSD. Fine-grained olivine-rich samples shows that Type-C fabric pattern is dominant, suggesting deformation under water-rich condition [3]. With metamorphic olivines, chlorite was also recrystallized, suggesting that water would be transported farther down to deep. The estimated dehydration reaction has a negative P-T slope at pressures higher than 1.5 GPa. The reaction is volume reducing reaction and the olivine-opx spinifex texture was formed under volume reducing reaction. In the warm slab beneath SW Japan, the reaction has a positive slope in P-T space and forms olivine+talc+fluid. From microstrucral and petrological analysis of the

  14. Chemical dehydration of specimens with 2,2-dimethoxypropane (DMP) for paraffin processing of animal tissues: practical and economic advantages over dehydration in ethanol.

    PubMed

    Conway, K; Kiernan, J A

    1999-01-01

    Chemical dehydration can be accomplished using 2,2-dimethoxypropane (DMP). In the presence of an acid catalyst, this liquid reacts with water generating methanol and acetone as products. Although DMP is more expensive per milliliter than ethanol and other solvents used for dehydration, it is an economical alternative because a much smaller volume is needed. Slow penetration of DMP was previously thought to restrict its use to tiny specimens, but we now show that pieces of tissue as thick as 2 cm are dehydrated by overnight immersion in acidified DMP. We also show that dehydration in acidified DMP does not impair the staining of RNA or other basophilic components of animal tissues. The temperature and concentrations of methanol and H+ in the chemical dehydrating agent are too low to produce histochemically detectable methylation or nucleic acid extraction.

  15. Characterization of dehydration-induced luminescence of kaolinite.

    PubMed

    Lahav, N; Coyne, L; Lawless, J G

    1985-01-01

    Dehydration-induced luminescence (DIL), the emission of light from a clay paste upon dehydration, was characterized experimentally for a colloidal kaolinite. The relationship between total photon count of the emitted light and film thickness is linear up to a thickness of 30 micrometers. The photon emission was obtained over a critical range of water contents (25-60%) of the oven-dry clay, and the kinetics of photon emission was presumed to be closely associated with the kinetics of film dehydration. Whether drying proceeded throughout the bulk or via a moving front was undetermined, but in either mode it was preceded by the formation of a thin dry film at the interface with the atmosphere. Grinding of the kaolinite for several minutes by mortar and pestle before paste preparations resulted in an overall increase of photon emission compared to unground kaolinite and in the formation of more than one emission peak, as well as a prolongation of the light emission. This effect on the kinetics of light emittance was observed for about two months after the application of the mechanical stress and suggests a means of detecting the mechanical stress history of a clay. An estimate was made of the spectral characteristics of the emitted light using optical filters and by incorporating tryptophan and salicylic acid into the kaolinite paste where they acted as fluorescent probes. The latter technique shifted the frequency of the light emitted by the kaolinite from the ultraviolet to the visible range where it was less effectively reabsorbed. The first method showed that the wavelengths of 97% of the emitted light was <460 nm and that 75% of the light had wavelengths < 410 nm. The second method showed that the total intensity of DIL increased in the presence of fluorescence molecules, suggesting that the emittance was in the ultraviolet range.

  16. Deformation-induced dehydration structures in the Nankai accretionary prism

    NASA Astrophysics Data System (ADS)

    Famin, V.; Byrne, T.; Lewis, J. C.; Kanagawa, K.; Behrmann, J.; Iodp 314/315/316 Scientists, E.

    2008-12-01

    This study investigates the chemical changes caused by deformation in the hanging wall of a major, probably seismogenic thrust fault in the Kumano forearc basin, Nankai Trough. In cores from IODP Expedition 315 (site C0001), the clay sediments display numerous deformation structures including tilted beddings, decimeter scale faults and shear zones with normal or thrust offsets, and clusters of parallel curviplanar veins interpreted as earthquake-induced dewatering structures. Curviplanar veins are often observed to merge into small oblique shear zones with millimeter offsets, or to branch on larger shear zones with a ~30° angle. This suggests that some shear zones may form by the coalescence of veins. Curviplanar veins and shear zones appear darker than the surrounding clay at the macroscopic observation scale, and brighter and therefore denser under CT-scan imaging. At the micro-scale, clay has a preferred crystallographic orientation in the deformation structures and no preferred orientation outside. Electron probe micro-analysis reveals that the dark material has a higher sum of major elements (65-80 wt%), i.e. a lower volatile content (assumed to be mostly water) than the host sediment (50-60 wt%). All the major elements are equally enriched in proportion to the volatile depletion. Mass balance calculation indicates that a 20-30 wt% water loss is required to account for chemical change in the deformation microstructures. The water loss may be due to clay dehydration or to pore collapse. Shear zones are equally dehydrated as the curviplanar veins from the mass balance standpoint. In 1 m3 of sediment, a deformed volume of 1 % should produce about 6.2 L of water. Given the low permeability of the sediment, dehydration may increase the pore pressure and enhance further deformation. Deformation localization would be self-sustained by fluid overpressure, suggesting that dewatering veins may evolve into larger deformation structures after an earthquake.

  17. Crystallization of a protein using dehydration without a precipitant

    PubMed Central

    Sharpe, Miriam L.; Baker, Edward N.; Lott, J. Shaun

    2005-01-01

    Hypoxic response protein I (HRPI) is a protein of unknown biochemical function whose expression is very strongly upregulated in response to oxygen depletion in Mycobacterium tuberculosis. Crystals have been grown from a solution of full-length HRPI by the unusual method of dehydration without the use of precipitants. The crystals produced diffract to a maximum resolution of 2.1 Å and belong to space group P41212 (or P43212), with unit-cell parameters a = b = 79.18, c = 37.34 Å. PMID:16511097

  18. Observations of denitrification and dehydration in the winter polar stratospheres

    NASA Technical Reports Server (NTRS)

    Fahey, D. W.; Kelly, K. K.; Kawa, S. R.; Tuck, A. F.; Loewenstein, M.

    1990-01-01

    It is argued that denitrification of the Arctic stratosphere can be explained by the selective growth and sedimentation of aerosol particles rich in nitric acid. Because reactive nitrogen species moderate the destruction of ozone by chlorine-catalyzed reactions by sequestering chlorine in reservoir species such as ClONO2, the possibility of the removal of reactive nitrogen without dehydration should be allowed for in attempts to model ozone depletion in the Arctic. Indeed, denitrification along with elevated concentrations of reactive chlorine observed in 1989 indicate that the Arctic was chemically primed for ozone destruction without an extended period of temperatures below the frost point, as is characteristic of the Antarctic.

  19. Dehydrative cross-coupling reactions of allylic alcohols with olefins.

    PubMed

    Gumrukcu, Yasemin; de Bruin, Bas; Reek, Joost N H

    2014-08-25

    The direct dehydrative activation of allylic alcohols and subsequent cross-coupling with alkenes by using palladium catalyst containing a phosphoramidite ligand is described. The activation of the allyl alcohol does not require stoichiometric additives, thus allowing clean, waste-free reactions. The scope is demonstrated by application of the protocol to a series allylic alcohols and vinyl arenes, leading to variety of 1,4-diene products. Based on kinetic studies, a mechanism is proposed that involves a palladium hydride species that activates the allyl alcohol to form the allyl intermediate.

  20. Mechanistic insights into the rhenium-catalyzed alcohol-to-olefin dehydration reaction.

    PubMed

    Korstanje, Ties J; Jastrzebski, Johann T B H; Klein Gebbink, Robertus J M

    2013-09-23

    Rhenium-based complexes are powerful catalysts for the dehydration of various alcohols to the corresponding olefins. Here, we report on both experimental and theoretical (DFT) studies into the mechanism of the rhenium-catalyzed dehydration of alcohols to olefins in general, and the methyltrioxorhenium-catalyzed dehydration of 1-phenylethanol to styrene in particular. The experimental and theoretical studies are in good agreement, both showing the involvement of several proton transfers, and of a carbenium ion intermediate in the catalytic cycle.

  1. Effects of dehydration on organ metabolism in the frog Pseudacris crucifer: hyperglycemic responses to dehydration mimic freezing-induced cryoprotectant production.

    PubMed

    Churchill, T A; Storey, K B

    1994-01-01

    The metabolic effects of evaporative water loss at 5 degrees C were assessed for both fall- and spring-collected spring peepers Pseudacris crucifer. Frogs readily endured the loss of 50% of total body water. During dehydration organ water content was defined with no change in water content in skeletal muscle, gut, and kidney of 50% dehydrated frogs and reduced water content in liver, brain and heart. Dehydration stimulated a rapid and massive increase in liver glucose production. In fall-collected frogs liver glucose rose by 120-fold to 2690 +/- 400 nmol.mg protein-1 or 220 mumol.g ww-1 in 50% dehydrated frogs and glucose in other organs increased by 2.6- to 60-fold. Spring-collected frogs showed the same qualitative response to dehydration although absolute glucose levels were lower, rising maximally by 8.4-fold in liver. Glucose synthesis was supported by glycogenolysis in liver and changes in the levels of glycolytic intermediates in liver indicated that an inhibitory block at the phosphofructokinase locus during desiccation helped to divert hexose phosphates into the production of glucose. Liver energy status (ATP, total adenylates, energy charge) was maintained even after the loss of 35% of total body water but at 50% dehydration all parameters showed a sharp decline; for example, energy charge fell from about 0.85 to 0.42. Severe dehydration also led to an accumulation of lactate in four organs, probably hypoxia-induced due to impaired circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Effects of dehydration on immune functions after a judo practice session.

    PubMed

    Chishaki, Takeharu; Umeda, Takashi; Takahashi, Ippei; Matsuzaka, Masashi; Iwane, Kaori; Matsumoto, Hidehiko; Ishibashi, Goshi; Ueno, Yuichi; Kashiwa, Naohiro; Nakaji, Shigeyuki

    2013-01-01

    We investigated the effects of dehydration after a judo practice session on player muscle and immune functions. Subjects included 25 female university judoists. Investigations were performed before and after 2.5 h of regular judo practice. Body composition, serum enzymes (myogenic enzymes, immunoglobulins and complements), neutrophils counts, reactive oxygen species (ROS) production capability, and phagocytic activity (PA) were measured. Subjects were divided into two groups according to level of dehydration after practice (mild dehydration and severe dehydration groups) and results were compared. Creatine kinase was found to increase significantly after practice. In addition, neutrophil count also increased significantly after practice in both groups. The changing ratios of IgA, IgG and C3 observed in the mild dehydration group were significantly higher than those in the severe dehydration group. In the severe dehydration group, post-practice PA/neutrophil had decreased significantly. Significant positive correlations were found between severity of dehydration and changing ratios of IgA, IgG, IgM, C3, C4 and ROS production capabilities, whereas no significant association was seen with PA and/or serum SOD activity. These results suggest that dehydration resulted in immunosuppression, including decreased neutrophil function.

  3. Severe hypercalcaemia and colon ischaemia: dehydration as an unusual cause?

    PubMed Central

    Fernandes, Liliana Gil; Ferreira, Nuno Ribeiro; Cardiga, Rosa; Póvoa, Pedro

    2015-01-01

    Hypercalcaemia is an emergency with severe consequences. Dehydration can be an uncommon cause of hypercalcaemia, as seen in this case. A 63-year-old woman with type 2 diabetes mellitus, hypothyroidism and osteoporosis, was admitted to the emergency room with abdominal distension and vomiting for 24 h. Initial evaluation was Hg 18.5 g/dL, Htc 56.2%, creatinine 2 mg/dL, metabolic acidaemia, lactate 8.3 mmol/L, anion gap 19, total Ca2+ 17.7 mg/dL and PO4+ 6.6 mg/dL. CT revealed colonic distension without obstruction or ischaemia. Renal replacement therapy and pamidronate were initiated. The patient's clinical condition deteriorated with septic shock in the context of toxic megacolon and she underwent an emergency subtotal colectomy (10 kg). Hypercalcaemia was corrected in 24 h with aggressive fluid replacement (8 L NaCl 0.9% first 12 h), with a reduction of total Ca2+ to 8.2 mg/dL. Other causes of hypercalcaemia were excluded. ‘Hypercalcaemic crisis’ secondary to severe acute dehydration is not mentioned in the literature. PMID:25809432

  4. Dehydration of isopropanol by pervaporation using aromatic polyetherimide membranes

    SciTech Connect

    Huang, R.Y.M.; Feng, X. )

    1993-08-01

    Aromatic polyetherimide membranes were prepared by the phase inversion method and tested for the pervaporation separation of water from isopropanol with emphasis on the breaking of azcotropic composition and the dehydration of high concentrations of isopropanol. It was found that the membrane selectivity was enhanced by partial evaporation of the solvent in the cast polymer films prior to the gelation step during membrane formation. The membrane performance was shown to be dependent on the feed concentration and the operating temperature. At a feed temperature of 25[degree]C and a permeate pressure of 133 Pa, separation factors of 173 and 384 were achieved for the dehydration of isopropanol solutions at 0.68 (azeotropic composition) and 0.96 mole fractions isopropanol, respectively, with reasonably high permeation rates. The utility of the membranes for the proposed separation was demonstrated; however, these membranes were not prepared under optimized conditions and thus a continuous study is required to rationalize the effects of membrane preparation parameters on membrane performance. 20 refs., 9 figs., 1 tab.

  5. Crystal structures of phosphoketolase: thiamine diphosphate-dependent dehydration mechanism.

    PubMed

    Suzuki, Ryuichiro; Katayama, Takane; Kim, Byung-Jun; Wakagi, Takayoshi; Shoun, Hirofumi; Ashida, Hisashi; Yamamoto, Kenji; Fushinobu, Shinya

    2010-10-29

    Thiamine diphosphate (ThDP)-dependent enzymes are ubiquitously present in all organisms and catalyze essential reactions in various metabolic pathways. ThDP-dependent phosphoketolase plays key roles in the central metabolism of heterofermentative bacteria and in the pentose catabolism of various microbes. In particular, bifidobacteria, representatives of beneficial commensal bacteria, have an effective glycolytic pathway called bifid shunt in which 2.5 mol of ATP are produced per glucose. Phosphoketolase catalyzes two steps in the bifid shunt because of its dual-substrate specificity; they are phosphorolytic cleavage of fructose 6-phosphate or xylulose 5-phosphate to produce aldose phosphate, acetyl phosphate, and H(2)O. The phosphoketolase reaction is different from other well studied ThDP-dependent enzymes because it involves a dehydration step. Although phosphoketolase was discovered more than 50 years ago, its three-dimensional structure remains unclear. In this study we report the crystal structures of xylulose 5-phosphate/fructose 6-phosphate phosphoketolase from Bifidobacterium breve. The structures of the two intermediates before and after dehydration (α,β-dihydroxyethyl ThDP and 2-acetyl-ThDP) and complex with inorganic phosphate give an insight into the mechanism of each step of the enzymatic reaction.

  6. Twin formation in hematite during dehydration of goethite

    NASA Astrophysics Data System (ADS)

    Saito, Genki; Kunisada, Yuji; Nomura, Takahiro; Sakaguchi, Norihito; Akiyama, Tomohiro

    2016-11-01

    Twin formation in hematite during dehydration was investigated using X-ray diffraction, electron diffraction, and high-resolution transmission electron microscopy (TEM). When synthetic goethite was heated at different temperatures between 100 and 800 °C, a phase transformation occurred at temperatures above 250 °C. The electron diffraction patterns showed that the single-crystalline goethite with a growth direction of [001]G was transformed into hematite with a growth direction of [100]H. Two non-equivalent structures emerged in hematite after dehydration, with twin boundaries at the interface between the two variants. As the temperature was increased, crystal growth occurred. At 800 °C, the majority of the twin boundaries disappeared; however, some hematite particles remained in the twinned variant. The electron diffraction patterns and high-resolution TEM observations indicated that the twin boundaries consisted of crystallographically equivalent prismatic (100) (010), and (1bar{1}0) planes. According to the total energy calculations based on spin-polarized density functional theory, the twin boundary of prismatic (100) screw had small interfacial energy (0.24 J/m2). Owing to this low interfacial energy, the prismatic (100) screw interface remained after higher-temperature treatment at 800 °C.

  7. Enzyme dehydration using Microglassification™ preserves the protein's structure and function.

    PubMed

    Aniket; Gaul, David A; Bitterfield, Deborah L; Su, Jonathan T; Li, Victoria M; Singh, Ishita; Morton, Jackson; Needham, David

    2015-02-01

    Controlled enzyme dehydration using a new processing technique of Microglassification™ has been investigated. Aqueous solution microdroplets of lysozyme, α-chymotrypsin, catalase, and horseradish peroxidase were dehydrated in n-pentanol, n-octanol, n-decanol, triacetin, or butyl lactate, and changes in their structure and function were analyzed upon rehydration. Water solubility and microdroplet dissolution rate in each solvent decreased in the order: butyl lactate > n-pentanol > triacetin > n-octanol > n-decanol. Enzymes Microglassified™ in n-pentanol retained higher activity (93%-98%) than n-octanol (78%-85%) or n-decanol (75%-89%), whereas those Microglassified™ in triacetin (36%-75%) and butyl lactate (48%-79%) retained markedly lower activity. FTIR spectroscopy analyses showed α-helix to β-sheet transformation for all enzymes upon Microglassification™, reflecting a loss of bound water in the dried state; however, the enzymes reverted to native-like conformation upon rehydration. Accelerated stressed-storage tests using Microglassified™ lysozyme showed a significant (p < 0.01) decrease in enzymatic activity from 46,560 ± 2736 to 31,060 ± 4327 units/mg after 3 months of incubation; however, it was comparable to the activity of the lyophilized formulation throughout the test period. These results establish Microglassification™ as a viable technique for enzyme preservation without affecting its structure or function.

  8. Structural and functional insights into asymmetric enzymatic dehydration of alkenols.

    PubMed

    Nestl, Bettina M; Geinitz, Christopher; Popa, Stephanie; Rizek, Sari; Haselbeck, Robert J; Stephen, Rosary; Noble, Michael A; Fischer, Max-Philipp; Ralph, Erik C; Hau, Hoi Ting; Man, Henry; Omar, Muhiadin; Turkenburg, Johan P; van Dien, Stephen; Culler, Stephanie J; Grogan, Gideon; Hauer, Bernhard

    2017-03-01

    The asymmetric dehydration of alcohols is an important process for the direct synthesis of alkenes. We report the structure and substrate specificity of the bifunctional linalool dehydratase isomerase (LinD) from the bacterium Castellaniella defragrans that catalyzes in nature the hydration of β-myrcene to linalool and the subsequent isomerization to geraniol. Enzymatic kinetic resolutions of truncated and elongated aromatic and aliphatic tertiary alcohols (C5-C15) that contain a specific signature motif demonstrate the broad substrate specificity of LinD. The three-dimensional structure of LinD from Castellaniella defragrans revealed a pentamer with active sites at the protomer interfaces. Furthermore, the structure of LinD in complex with the product geraniol provides initial mechanistic insights into this bifunctional enzyme. Site-directed mutagenesis confirmed active site amino acid residues essential for its dehydration and isomerization activity. These structural and mechanistic insights facilitate the development of hydrating catalysts, enriching the toolbox for novel bond-forming biocatalysis.

  9. Dehydration-induced amorphous phases of calcium carbonate.

    PubMed

    Saharay, Moumita; Yazaydin, A Ozgur; Kirkpatrick, R James

    2013-03-28

    Amorphous calcium carbonate (ACC) is a critical transient phase in the inorganic precipitation of CaCO3 and in biomineralization. The calcium carbonate crystallization pathway is thought to involve dehydration of more hydrated ACC to less hydrated ACC followed by the formation of anhydrous ACC. We present here computational studies of the transition of a hydrated ACC with a H2O/CaCO3 ratio of 1.0 to anhydrous ACC. During dehydration, ACC undergoes reorganization to a more ordered structure with a significant increase in density. The computed density of anhydrous ACC is similar to that of calcite, the stable crystalline phase. Compared to the crystalline CaCO3 phases, calcite, vaterite, and aragonite, the computed local structure of anhydrous ACC is most-similar to those of calcite and vaterite, but the overall structure is not well described by either. The strong hydrogen bond interaction between the carbonate ions and water molecules plays a crucial role in stabilizing the less hydrated ACC compositions compared to the more hydrated ones, leading to a progressively increasing hydration energy with decreasing water content.

  10. Skeletal muscle volume following dehydration induced by exercise in heat

    PubMed Central

    2012-01-01

    Background Intracellular skeletal muscle water is redistributed into the extracellular compartment during periods of dehydration, suggesting an associated decline in muscle volume. The purpose of this study was to evaluate skeletal muscle volume in active (knee extensors (KE)) and less active (biceps/triceps brachii, deltoid) musculature following dehydration induced by exercise in heat. Methods Twelve participants (seven men, five women) cycled in the heat under two conditions: (1) dehydration (DHYD) resulting in 3% and 5% losses of estimated total body water (ETBW), which was assessed by changes in body mass, and (2) fluid replacement (FR) where 3% and 5% losses of ETBW were counteracted by intermittent (20 to 30 min) fluid ingestion via a carbohydrate-electrolyte beverage. During both conditions, serum osmolality and skeletal muscle volume (assessed by magnetic resonance imaging) were measured at baseline and at the 3% and 5% ETBW loss measurement points. Results In DHYD, serum osmolality increased at 3% (p = 0.005) and 5% (p < 0.001) ETBW losses, while FR decreased serum osmolality at the 5% loss of ETBW time point (p = 0.009). In DHYD, KE muscle volume declined from 1,464 ± 446 ml to 1,406 ± 425 ml (3.9%, p < 0.001) at 3% ETBW loss and to 1,378 ± 421 ml (5.9%, p < 0.001) at 5% ETBW loss. The largest decline in KE volume in DYHD occurred in the mid-belly (31 ml, p = 0.001) and proximal (24 ml, p = 0.001) regions of the grouped vasti muscles. There were no changes in volume for the biceps/triceps (p = 0.35) or deltoid (p = 0.92) during DHYD. FR prevented the loss of KE muscle volume at 3% (1,430 ± 435 ml, p = 0.074) and 5% (1,431 ± 439 ml, p = 0.156) ETBW loss time points compared to baseline (1,445 ± 436 ml). Conclusions Following exercise in the heat, the actively contracting muscles lost volume, while replacing lost fluids intermittently during exercise in heat prevented this decline

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

    EPA Science Inventory

    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...

  12. Quality of frozen fruit bars manufactured through infrared pre-dehydration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  13. Exercise-induced hemolysis in xerocytosis. Erythrocyte dehydration and shear sensitivity.

    PubMed Central

    Platt, O S; Lux, S E; Nathan, D G

    1981-01-01

    A patient with xerocytosis was found to have swimming-induced intravascular hemolysis and shortening of erythrocyte life-span. In a microviscometer, xerocytes were more susceptible than normal erythrocytes to hemolysis by shear stress. Fractionation of normal and abnormal cells on discontinuous Stractan density gradients revealed that increasingly dehydrated cells were increasingly more shear sensitive. This sensitivity was partially corrected by rehydrating xerocytic erythrocytes by means of the cation-ionophore nystatin in a high potassium buffer. Conversely, normal erythrocytes were rendered shear sensitive by dehydrating them with nystatin in a low potassium buffer. This effect of dehydration was entirely reversible if normal cells were dehydrated for less than 4 h but was only partially reversed after more prolonged dehydration. It is likely that dehydration of erythrocytes results in shear sensitivity primarily because of concentration of cell contents and reduced cellular deformability. With prolonged dehydration, secondary membrane changes may potentiate the primary effect. This increased shear sensitivity of dehydrated cells may explain atraumatic exercise-induced hemolysis in xerocytosis as cardiac output is shifted to vessels of exercising muscles with small diameters and high shear rates. PMID:7276163

  14. 21 CFR 573.400 - Ethoxyquin in certain dehydrated forage crops.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... and vitamin E in the forage crops. (c) It is added to the dehydrated forage crops in an oil mixture containing only suitable animal or suitable vegetable oil, prior to grinding and mixing. (d) The maximum... vegetable oils are to be used in the oil mix. (f) The label of any dehydrated forage crops treated with...

  15. 21 CFR 573.400 - Ethoxyquin in certain dehydrated forage crops.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... and vitamin E in the forage crops. (c) It is added to the dehydrated forage crops in an oil mixture containing only suitable animal or suitable vegetable oil, prior to grinding and mixing. (d) The maximum... vegetable oils are to be used in the oil mix. (f) The label of any dehydrated forage crops treated with...

  16. 21 CFR 573.400 - Ethoxyquin in certain dehydrated forage crops.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... and vitamin E in the forage crops. (c) It is added to the dehydrated forage crops in an oil mixture containing only suitable animal or suitable vegetable oil, prior to grinding and mixing. (d) The maximum... vegetable oils are to be used in the oil mix. (f) The label of any dehydrated forage crops treated with...

  17. 21 CFR 573.400 - Ethoxyquin in certain dehydrated forage crops.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... and vitamin E in the forage crops. (c) It is added to the dehydrated forage crops in an oil mixture containing only suitable animal or suitable vegetable oil, prior to grinding and mixing. (d) The maximum... vegetable oils are to be used in the oil mix. (f) The label of any dehydrated forage crops treated with...

  18. Chemical and physicochemical quality parameters in carrots dehydrated by power ultrasound.

    PubMed

    Soria, Ana Cristina; Corzo-Martínez, Marta; Montilla, Antonia; Riera, Enrique; Gamboa-Santos, Juliana; Villamiel, Mar

    2010-07-14

    Preservation of the quality and bioactivity of carrots dehydrated by power ultrasound (US) under different experimental conditions including prior blanching has been evaluated for the first time by measuring the evolution of the Maillard reaction and the changes in soluble sugars, proteins, total polyphenols, antioxidant activity, and rehydration ability. This study also includes a comparison with a freeze-dried sample and data of commercial dehydrated carrots. The synergic effect of US and temperature (60 degrees C) increased the dehydration rate of carrots (90% moisture loss in only 75 min) while still providing carrots with a level of 2-furoylmethyl-amino acids significantly lower than that of dehydrated commercial samples. Whereas a decrease in the content of reducing soluble sugars was observed with processing temperature, minor carbohydrates (scyllo- and myo-inositol and sedoheptulose) were rather stable, irrespective of the US dehydration parameters. Blanching significantly improved the rehydration ability of US-dehydrated carrots without increasing the loss of soluble sugars by leaching. As supported by the similarity of most quality indicators studied in both US-treated and freeze-dried carrots, the mild processing conditions employed in US dehydration gave rise to premium quality dehydrated carrots.

  19. Dehydration of 2-Methyl-1-Cyclohexanol: New Findings from a Popular Undergraduate Laboratory Experiment

    ERIC Educational Resources Information Center

    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…

  20. Simultaneous Infrared Dry-Blanching and Dehydration of apple slices Controlled by Intermittent Heating Mode

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infrared heating controlled by intermittent heating mode was found to be able to achieve simultaneous dry-blanching and dehydration of apple slices with a desirable quality. In order to better understand the performance of intermittent heating for simultaneous dry-blanching and dehydration (SIDBD),...

  1. Rehydration of a reattached fractured tooth fragment after prolonged dehydration.

    PubMed

    Arhun, Neslihan; Onay, Emel Olga; Ungor, Mete

    2012-01-01

    Crown fractures of the anterior teeth are one of the most common outcomes of trauma to the orofacial region. The reattachment of dental fragments is a conservative treatment and should be considered a primary treatment choice in the restoration of anterior tooth fractures. This article presents a clinical technique for the restoration of a fractured maxillary lateral incisor by reattaching the tooth fragment that was kept in dry conditions for five days with the aid of adhesive dentistry. The esthetic compromise of white color (due to excessive dehydration of the segment) was reconciled after one month of service in the mouth by regaining the natural color by rehydration. The one-year clinical evaluation revealed a successful outcome for this technique, and the patient was pleased with the esthetic results of the conservative treatment modality.

  2. Dehydration of oil waste emulsions by means of flocculants

    SciTech Connect

    Gandurina, L.V.; Butseva, L.N.; Shtondina, V.S.

    1995-05-01

    Oil waste emulsions are formed in the course of pumping petroleum crudes and products and are collected from the surfaces of equipment in recirculating water systems and wastewater disposal facilities (oil separators, sand traps, oil traps, holding pits for accidental spills, settlers, ponds, sludge accumulators, and so on). Emulsions are also obtained in the course of cleaning equipment in crude oil desalting and dehydration units. Such emulsions are stable, structurized systems that are very resistant to dewatering by heating and settling in separator tanks. In order to break stabilized emulsions, i.e., in order to ensure complete coalescence of drops when they collide, it is not sufficient to increase the forces of mutual attraction of drops at the moment of collision; in addition, the protective shell must be either destroyed or weakened. Demulsifying agents, or surfactants, will displace the stabilizers. This report is concerned with demulsifier efficiency.

  3. Dehydration of water-pyridine mixtures by pervaporation

    SciTech Connect

    Kujawski, W. Centre National de la Recherche Scientifique-UA 494, Nancy ); Nguyen, T.Q.; Neel, J. )

    1991-08-01

    The pervaporation technique, in which the liquid feed mixture is maintained in contact with one side of a nonporous membrane and the permeate is continuously removed from the other side as a vapor, is one of the new methods to attain separation of azeotropic mixtures, structural isomers, or even to displace the equilibrium of chemical reactions. Several ion-exchange and neutral membranes were examined in the pervaporation of water-pyridine mixtures. Carboxylic and sulfonic ion-exchange membranes were used with hydrogen counterion and additionally with trimethylammonium, triethylammonium, and tributylammonium counterions. All membranes were selective to water, but the transport mode and selectivity properties of membranes were dependent on both the character of the ion-exchange group and the ionic form of the membrane. The results obtained suggest that pervaporation of water-pyridine mixtures could be used with standard distillation in the large-scale dehydration process of pyridine.

  4. Characterization of dehydration-induced luminescence of kaolinite

    NASA Technical Reports Server (NTRS)

    Lahav, N.; Coyne, L.; Lawless, J. G.

    1985-01-01

    The dehydration-induced luminescence of a colloidal kaolinite is investigated experimentally, with particular attention given to the effect of various treatments on the luminescence characteristics. It is found that the total photon count of the emitted light is linearly related to the film thickness up to a thickness of 30 microns; mechanical stress in the form of grinding increases the photon output and produces extensive changes in the emission kinetics. A direct check of the emission wavelength dependence (by using color filters) indicates that roughly 75 percent of the emission occurs in the wavelength range below 410 nm. It is also found that incorporation of fluorescent molecules into the kaolinite paste increases the photon output and may indicate the transfer of ultraviolet photons to the fluorescent probe.

  5. Hypernatraemic dehydration and breast feeding: a population study

    PubMed Central

    Oddie, S; Richmond, S; Coulthard, M

    2001-01-01

    As part of a population based regional review of all neonatal readmissions, the incidence of dehydration with hypernatraemia in exclusively breast fed infants was estimated. All readmissions to hospital in the first month of life during 1998 from a population of 32 015 live births were reviewed. Eight of 907 readmissions met the case definition, giving an incidence of at least 2.5 per 10 000 live births. Serum sodium at readmission varied from 150to 175 mmol/l. One infant had convulsions. The sole explanation for hypernatraemia was unsuccessful breast feeding in all cases. The eight cases are compared with the 65 cases published in the literature since 1979. Presentation, incidence, risk factors, pathophysiology, treatment, and prevention are discussed.

 PMID:11567942

  6. ROLE OF PRESSURE IN SMECTITE DEHYDRATION - EFFECTS ON GEOPRESSURE AND SMECTITE-TO-ILLITE TRANSFORMATION.

    USGS Publications Warehouse

    Colten-Bradley, Virginia

    1987-01-01

    Evaluation of the effects of pressure on the temperature of interlayer water loss (dehydration) by smectites under diagenetic conditions indicates that smectites are stable as hydrated phases in the deep subsurface. Hydraulic and differential pressure conditions affect dehydration differently. The temperature of dehydration increase with pore fluid pressure and interlayer water density. The temperatures of dehydration increase with pore fluid pressure and interlayer water density. The temperatures of dehydration under differential-presssure conditions are inversely related to pressure and interlayer water density. The model presented assumes the effects of pore fluid composition and 2:1 layer reactivity to be negligible. Agreement between theoretical and experimental results validate this assumption. Additional aspects of the subject are discussed.

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

    PubMed

    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.

  8. A generic protocol for protein crystal dehydration using the HC1b humidity controller

    PubMed Central

    Lobley, Carina M. C.; Sandy, James; Sanchez-Weatherby, Juan; Mazzorana, Marco; Krojer, Tobias; Nowak, Radosław P.; Sorensen, Thomas L.

    2016-01-01

    Dehydration may change the crystal lattice and affect the mosaicity, resolution and quality of X-ray diffraction data. A dehydrating environment can be generated around a crystal in several ways with various degrees of precision and complexity. This study uses a high-precision crystal humidifier/dehumidifier to provide an airstream of known relative humidity in which the crystals are mounted: a precise yet hassle-free approach to altering crystal hydration. A protocol is introduced to assess the impact of crystal dehydration systematically applied to nine experimental crystal systems. In one case, that of glucose isomerase, dehydration triggering a change of space group from I222 to P21212 was observed. This observation is supported by an extended study of the behaviour of the glucose isomerase crystal structure during crystal dehydration. PMID:27139626

  9. Anhydrobiosis in yeast: influence of calcium and magnesium ions on yeast resistance to dehydration-rehydration.

    PubMed

    Trofimova, Yuliya; Walker, Graeme; Rapoport, Alexander

    2010-07-01

    The influence of calcium and magnesium ions on resistance to dehydration in the yeast, Saccharomyces cerevisiae, was investigated. Magnesium ion availability directly influenced yeast cells' resistance to dehydration and, when additionally supplemented with calcium ions, this provided further significant increase of yeast resistance to dehydration. Gradual rehydration of dry yeast cells in water vapour indicated that both magnesium and calcium may be important for the stabilization of yeast cell membranes. In particular, calcium ions were shown for the first time to increase the resistance of yeast cells to dehydration in stress-sensitive cultures from exponential growth phases. It is concluded that magnesium and calcium ion supplementations in nutrient media may increase the dehydration stress tolerance of S. cerevisiae cells significantly, and this finding is important for the production of active dry yeast preparations for food and fermentation industries.

  10. Effect of dehydration on the electrical conductivity of phyllite at high temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Sun, Wenqing; Dai, Lidong; Li, Heping; Hu, Haiying; Jiang, Jianjun; Hui, Keshi

    2017-02-01

    The electrical conductivity of phyllite (measured in situ at 0.5-2.5 GPa and 773-1173 K) increases with increasing temperature, satisfying an Arrhenius relation. Dehydration of phyllite at 973-1173 K enormously enhances its electrical conductivity, and the activation enthalpy (0.64-0.81 eV) remains almost constant before and after dehydration. The inflection point of the relationship between electrical conductivity and temperature is used to determine the dehydration temperature (T d ) at each considered pressure (P), leading to the following relationship: T d = 1181 - 100P. The derived relation implies that the dehydration depths of hot and cold subduction zones are 70 and 129 km respectively, which are both close to the depths of arc magma source regions, thereby indicating that the dehydration of pelite significantly influences the generation of melt in subduction zones.

  11. Dehydration of isobutanol to isobutene in a slurry reactor

    SciTech Connect

    Latshaw, B.E.

    1994-02-01

    The April 1990 Alternative Fuels Proposal to the Department of Energy involved the development of new technology, based on the liquid phase process, for conversion of coal-derived synthesis gas to oxygenated hydrocarbon fuels, fuel additives, and fuel intermediates. The objective of this work was to develop a slurry reactor based process for the dehydration of isobutanol to isobutene. The isobutene can serve as a feedstock for the high octane oxygenated fuel additive methyl tertiary-butyl either (MTBE). Alumina catalysts were investigated because of their wide use as a dehydration catalyst. Four commercially available alumina catalysts (Catapal B, Versal B, Versal GH, and Al-3996R) were evaluated for both activity and selectivity to the branched olefin. All four catalysts demonstrated conversions greater than 80% at 290 C, while conversions of near 100% could be obtained at 330 C. The reaction favors low pressures and moderate to low space velocities. A yield of 0.90 mole isobutene per mole reacted isobutanol or better was obtained at conversions of 60--70% and higher. From 75 to 98% conversion, the four catalysts all provide isobutene yields ranging from 0.92 to 0.94 with the maximum occurring around 90% conversion. At low conversions, the concentration of diisobutyl ether becomes significant while the concentration of linear butenes is essentially a linear function of isobutanol conversion. Doping the catalyst with up to 0.8 wt % potassium showed a modest increase in isobutene selectivity; however, this increase was more than offset by a reduction in activity. Investigations using a mixed alcohols feed (consistent with isobutanol synthesis from syngas) demonstrated a small increase in the C4 iso-olefin selectivity over that observed for a pure isobutanol feed. 55 refs.

  12. Advancing microwave technology for dehydration processing of biologics.

    PubMed

    Cellemme, Stephanie L; Van Vorst, Matthew; Paramore, Elisha; Elliott, Gloria D

    2013-10-01

    Our prior work has shown that microwave processing can be effective as a method for dehydrating cell-based suspensions in preparation for anhydrous storage, yielding homogenous samples with predictable and reproducible drying times. In the current work an optimized microwave-based drying process was developed that expands upon this previous proof-of-concept. Utilization of a commercial microwave (CEM SAM 255, Matthews, NC) enabled continuous drying at variable low power settings. A new turntable was manufactured from Ultra High Molecular Weight Polyethylene (UHMW-PE; Grainger, Lake Forest, IL) to provide for drying of up to 12 samples at a time. The new process enabled rapid and simultaneous drying of multiple samples in containment devices suitable for long-term storage and aseptic rehydration of the sample. To determine sample repeatability and consistency of drying within the microwave cavity, a concentration series of aqueous trehalose solutions were dried for specific intervals and water content assessed using Karl Fischer Titration at the end of each processing period. Samples were dried on Whatman S-14 conjugate release filters (Whatman, Maidestone, UK), a glass fiber membrane used currently in clinical laboratories. The filters were cut to size for use in a 13 mm Swinnex(®) syringe filter holder (Millipore(™), Billerica, MA). Samples of 40 μL volume could be dehydrated to the equilibrium moisture content by continuous processing at 20% with excellent sample-to-sample repeatability. The microwave-assisted procedure enabled high throughput, repeatable drying of multiple samples, in a manner easily adaptable for drying a wide array of biological samples. Depending on the tolerance for sample heating, the drying time can be altered by changing the power level of the microwave unit.

  13. Spring dehydration in the Antarctic stratospheric vortex observed by HALOE

    NASA Technical Reports Server (NTRS)

    Pierce, R. Bradley; Grose, William L.; Russell, James M., III; Tuck, Adrian F.; Swinbank, Richard; O'Neill, Alan

    1994-01-01

    The distribution of dehydrated air in the middle and lower stratosphere during the 1992 Southern Hemisphere spring is investigated using Halogen Occultation Experiment (HALOE) observations and trajectory techniques. Comparisons between previously published Version 9 and the improved Version 16 retrievals on the 700-K isentropic surface show very slight (0.05 ppmv) increases in Version 16 CH4 relative to Version 9 within the polar vortex. Version 16 H2O mixing ratios show a reduction of 0.5 ppmv relative to Version 9 within the polar night jet and a reduction of nearly 1.0 ppmv in middle latitudes when compared to Version 9. The version 16 HALOE retrievals show low mixing ratios of total hydrogen (2CH4 + H2O) within the polar vortex on both 700 and 425 K isentropic surfaces relative to typical middle-stratospheric 2CH4 + H2O mixing ratios. The low 2CH4 + H2O mixing ratios are associated with dehydration. Slight reductions in total hydrogen, relative to typical middle-stratospheric values, are found at these levels throughout the Southern Hemisphere during this period. Trajectory calculations show that middle-latitude air masses are composed of a mixture of air from within the polar night jet and air from middle latitudes. A strong kinematic barrier to large-scale exchange is found on the poleward flank of the polar night jet at 700 K. A much weaker kinematic barrier is found at 425 K. The impact of the finite tangent pathlength of the HALOE measurements is investigated using an idealized tracer distribution. This experiment suggests that HALOE should be able to resolve the kinematic barrier, if it exists.

  14. Dehydration improves cryopreservation of coconut (Cocos nucifera L.).

    PubMed

    Sisunandar; Sopade, Peter A; Samosir, Yohannes M S; Rival, Alain; Adkins, Steve W

    2010-12-01

    Cryopreservation of coconut can be used as a strategy to back up the establishment of living collections which are expensive to maintain and are under constant threat from biotic and abiotic factors. Unfortunately, cryopreservation protocols still need to be developed that are capable of producing a sizeable number of field-grown plants. Therefore, we report on the development of an improved cryopreservation protocol which can be used on a wide range of coconut cultivars. The cryopreservation of zygotic embryos and their recovery to soil-growing plants was achieved through the application of four optimised steps viz.: (i) rapid dehydration; (ii) rapid cooling; (iii) rapid warming and recovery in vitro and (iv) acclimatization and soil-supported growth. The thermal properties of water within the embryos were monitored using differential scanning calorimetry (DSC) in order to ensure that the freezable component was kept to a minimum. The feasibility of the protocol was assessed using the Malayan Yellow Dwarf (MYD) cultivar in Australia and then tested on a range of cultivars which were freshly harvested and studied in Indonesia. The most efficient protocol was one based on an 8-h rapid dehydration step followed by rapid cooling step. Best recovery percentages were obtained when a rapid warming step and an optimised in vitro culture step were used. Following this protocol, 20% (when cryopreserved 12 days after harvesting) and 40% (when cryopreserved at the time of harvest) of all MYD embryos cryopreserved could be returned to normal seedlings growing in soil. DSC showed that this protocol induced a drop in embryo fresh weight to 19% and significantly reduced the amount of water remaining that could produce ice crystals (0.1%). Of the 20 cultivars tested, 16 were found to produce between 10% and 40% normal seedlings while four cultivars generated between 0% and 10% normal seedlings after cryopreservation. This new protocol is applicable to a wide range of coconut

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

    PubMed

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

    2013-05-01

    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.

  16. Effects of dehydration on cardiovascular development in the embryonic American alligator (Alligator mississipiensis).

    PubMed

    Tate, Kevin B; Eme, John; Swart, Justin; Conlon, J Michael; Crossley, Dane A

    2012-07-01

    Effects of dehydration on reptilian embryonic cardiovascular function are unknown. Here, we present the first morphological and physiological data quantifying the cumulative effects of four acute dehydration events on the embryonic American alligator, Alligator mississipiensis. We hypothesized that dehydration would alter embryonic morphology, reduce blood volume and augment the response to angiotensin II (Ang II), a key osmotic and blood volume regulatory response element in adult vertebrates. Drying events at 30%, 40%, 50%, and 60% of embryonic incubation reduced total egg water content by 14.43 ± 0.37 g, a 3.4 fold increase relative to controls. However, embyronic blood volume was greater in the dehydration group at 70% of embryonic incubation compared to controls (0.39 ± 0.044 mLg(-1) and 0.22 ± 0.03 mLg(-1), respectively), however, both groups were similar at 90% of incubation (0.18 ± 0.02 mLg(-1) in the controls and 0.23 ± 0.03 mLg(-1) in the dehydrated group). Dehydration altered the morphological phenotype and resulted in an overall reduction in embryonic mass at both incubation time points measured. Dehydration also altered the physiological phenotype, resulting in embryonic alligators that were relatively bradycardic at 90% of incubation. Arterial Ang II injections resulted in a dose dependent hypertension, which increased in intensity over the span of incubation studied. While progressive incubation altered the Ang II response, dehydration had no impact on the cardiovascular responses to the peptide. Quantification of Ang II type-1 receptor protein using western blot analysis illustrated that dehydration condition and incubation time point did not alter protein quantity. Collectively, our results show that dehydration during embryonic development of the American alligator alters embryonic morphology and baseline heart rate without altering arterial pressure and response to Ang II.

  17. 'Fortified' wines volatile composition: Effect of different postharvest dehydration conditions of wine grapes cv. Malvasia moscata (Vitis vinifera L.).

    PubMed

    Urcan, Delia Elena; Giacosa, Simone; Torchio, Fabrizio; Río Segade, Susana; Raimondi, Stefano; Bertolino, Marta; Gerbi, Vincenzo; Pop, Nastasia; Rolle, Luca

    2017-03-15

    The impact of postharvest dehydration on the volatile composition of Malvasia moscata grapes and fortified wines produced from them was assessed. The ripeness effect of fresh grapes on volatile compounds of dehydrated grapes was evaluated for the first time in this study. Fresh grape berries were densimetrically sorted, and more represented density classes were selected. Dehydration of riper berries (20.5 °Brix) led to volatile profiles richer in terpenes, particularly linalool and geraniol. The effect of dehydration rate on the volatile composition of dehydrated grapes and fortified wines was also evaluated. Fast dehydration grapes were richer in total free terpenes, and the resulting wines contained greater amounts of volatile compounds. The predominant compounds were free esters, but linalool, rose oxide, citronellol and geraniol can also contribute to wine aroma, particularly for fast dehydration. β-Damascenone can be an active odorant, although its contribution was greater in wines made from slow dehydrated grapes.

  18. Insights into the dehydration behavior of thiamine hydrochloride (vitamin B1) hydrates: part I.

    PubMed

    Chakravarty, Paroma; Berendt, Robert T; Munson, Eric J; Young, Victor G; Govindarajan, Ramprakash; Suryanarayanan, Raj

    2010-02-01

    Thiamine hydrochloride (Vitamin B(1), THCl) can exist as a nonstoichiometric hydrate (NSH) and as a hemihydrate (HH). NSH can contain up to approximately 1 molar equivalent of water and be dehydrated to an isomorphic desolvate (ID) with minimal change in lattice structure. Crystallographic and spectroscopic techniques were used to characterize the influence of structure and mobility on NSH dehydration. Dehydration was accompanied by lattice contraction, as noted by a decrease in the d-spacings. Dehydration also led to the development of surface cracks parallel to the (101*) and (102*) planes in the NSH single crystal, as observed by hot stage microscopy. Step-wise dehydration of NSH produced gradual shifts in XRPD and SSNMR peaks, indicating that NSH (with approximately 1 mole water) and ID represent the two extremes of a continuum in the hydration state. Variable temperature (13)C SSNMR studies showed that water molecules move rapidly at room temperature within the NSH crystal lattice, and the thiamine molecules transiently exist in distinct hydrated and dehydrated states. It is hypothesized that, despite the lack of continuous hydration channels in the NSH crystal lattice, cooperative deformation of the thiamine molecules allows a nondisruptive departure of water molecules from the lattice during dehydration.

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

    PubMed

    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.

  20. Characterization of the ABA-regulated global responses to dehydration in Arabidopsis by metabolomics.

    PubMed

    Urano, Kaoru; Maruyama, Kyonoshin; Ogata, Yoshiyuki; Morishita, Yoshihiko; Takeda, Migiwa; Sakurai, Nozomu; Suzuki, Hideyuki; Saito, Kazuki; Shibata, Daisuke; Kobayashi, Masatomo; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo

    2009-03-01

    Drought is the major environmental threat to agricultural production and distribution worldwide. Adaptation by plants to dehydration stress is a complex biological process that involves global changes in gene expression and metabolite composition. Here, using one type of functional genomics analysis, metabolomics, we characterized the metabolic phenotypes of Arabidopsis wild-type and a knockout mutant of the NCED3 gene (nc3-2) under dehydration stress. NCED3 plays a role in the dehydration-inducible biosynthesis of abscisic acid (ABA), a phytohormone that is important in the dehydration-stress response in higher plants. Metabolite profiling performed using two types of mass spectrometry (MS) systems, gas chromatography/time-of-flight MS (GC/TOF-MS) and capillary electrophoresis MS (CE-MS), revealed that accumulation of amino acids depended on ABA production, but the level of the oligosaccharide raffinose was regulated by ABA independently under dehydration stress. Metabolic network analysis showed that global metabolite-metabolite correlations occurred in dehydration-increased amino acids in wild-type, and strong correlations with raffinose were reconstructed in nc3-2. An integrated metabolome and transcriptome analysis revealed ABA-dependent transcriptional regulation of the biosynthesis of the branched-chain amino acids, saccharopine, proline and polyamine. This metabolomics analysis revealed new molecular mechanisms of dynamic metabolic networks in response to dehydration stress.

  1. Unusual effect of water vapor pressure on dehydration of dibasic calcium phosphate dihydrate.

    PubMed

    Kaushal, Aditya M; Vangala, Venu R; Suryanarayanan, Raj

    2011-04-01

    Dibasic calcium phosphate occurs as an anhydrate (DCPA; CaHPO₄) and as a dihydrate (DCPD; CaHPO₄•2H₂O). Our objective was to investigate the unusual behavior of these phases. Dibasic calcium phosphate dihydrate was dehydrated in a (i) differential scanning calorimeter (DSC) in different pan configurations; (ii) variable-temperature X-ray diffractometer (XRD) at atmospheric and under reduced pressure, and in sealed capillaries; and (iii) water vapor sorption analyzer at varying temperature and humidity conditions. Dehydration was complete by 210°C in an open DSC pan and under atmospheric pressure in the XRD. Unlike "conventional" hydrates, the dehydration of DCPD was facilitated in the presence of water vapor. Variable-temperature XRD in a sealed capillary and DSC in a hermetic pan with pinhole caused complete dehydration by 100°C and 140°C, respectively. Under reduced pressure, conversion to the anhydrate was incomplete even at 300°C. The increase in dehydration rate with increase in water vapor pressure has been explained by the Smith-Topley effect. Under "dry" conditions, a coating of poorly crystalline product is believed to form on the surface of particles and act as a barrier to further dehydration. However, in the presence of water vapor, recrystallization occurs, creating cracks and channels and facilitating continued dehydration.

  2. Analysis of plant hormone profiles in response to moderate dehydration stress.

    PubMed

    Urano, Kaoru; Maruyama, Kyonoshin; Jikumaru, Yusuke; Kamiya, Yuji; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo

    2017-04-01

    Plant responses to dehydration stress are mediated by highly complex molecular systems involving hormone signaling and metabolism, particularly the major stress hormone abscisic acid (ABA) and ABA-dependent gene expression. To understand the roles of plant hormones and their interactions during dehydration, we analyzed the plant hormone profiles with respect to dehydration responses in Arabidopsis thaliana wild-type (WT) plants and ABA biosynthesis mutants (nced3-2). We developed a procedure for moderate dehydration stress, and then investigated temporal changes in the profiles of ABA, jasmonic acid isoleucine (JA-Ile), salicylic acid (SA), cytokinin (trans-zeatin, tZ), auxin (indole-acetic acid, IAA), and gibberellin (GA4 ), along with temporal changes in the expression of key genes involved in hormone biosynthesis. ABA levels increased in a bi-phasic pattern (at the early and late phases) in response to moderate dehydration stress. JA-Ile levels increased slightly in WT plants and strongly increased in nced3-2 mutant plants at 72 h after the onset of dehydration. The expression profiles of dehydration-inducible genes displayed temporal responses in an ABA-dependent manner. The early phase of ABA accumulation correlated with the expression of touch-inducible genes and was independent of factors involved in the major ABA regulatory pathway, including the ABA-responsive element-binding (AREB/ABF) transcription factor. JA-Ile, SA, and tZ were negatively regulated during the late dehydration response phase. Transcriptome analysis revealed important roles for hormone-related genes in metabolism and signaling during dehydration-induced plant responses.

  3. Influence of environmental conditions on the kinetics and mechanism of dehydration of carbamazepine dihydrate.

    PubMed

    Han, J; Suryanarayanan, R

    1998-11-01

    The object of this project was to study the influence of temperature and water vapor pressure on the kinetics and mechanism of dehydration of carbamazepine dihydrate and to establish the relationship between the dehydration mechanism and the solid-state of the anhydrous phase formed. Three experimental techniques were utilized to study the kinetics of dehydration of carbamazepine dihydrate (C15H12N2O.2H2O)-thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and variable temperature powder X-ray diffractometry (VTXRD). These techniques respectively provide information about the changes in weight, heat flow and solid-state (phase) during the dehydration process. The instrumental setup was modified so that simultaneous control of both the temperature and the water vapor pressure was possible. The experiments were carried out at different temperatures, ranging from 26 to 64 degrees C. In the absence of water vapor, the dehydration followed the 2-dimensional phase boundary controlled model at all the temperatures studied. In the next stage, the water vapor pressure was altered while the studies were carried out at a single temperature of 44 degrees C. The dehydration was 2-dimensional phase boundary controlled at water vapor pressures < or = 5.1 torr while the Avrami-Erofeev kinetics (3-dimensional nucleation) was followed at water vapor pressures > or = 12.0 torr. In the former case, the anhydrous phase formed was X-ray amorphous while it was the crystalline anhydrous gamma-carbamazepine in the latter. Thus a relationship between the mechanism of dehydration and the solid-state of the product phase was evident. The dehydration conditions influence not only the mechanism but also the solid-state of the anhydrous phase formed. While the techniques of TGA and DSC have found extensive use in studying dehydration reactions, VTXRD proved to be an excellent complement in characterizing the solid-states of the reactant and product phases.

  4. Haemodynamic responses to dehydration in the resting and exercising human leg.

    PubMed

    Pearson, James; Kalsi, Kameljit K; Stöhr, Eric J; Low, David A; Barker, Horace; Ali, Leena; González-Alonso, José

    2013-06-01

    Dehydration and hyperthermia reduces leg blood flow (LBF), cardiac output ([Formula: see text]) and arterial pressure during whole-body exercise. It is unknown whether the reductions in blood flow are associated with dehydration-induced alterations in arterial blood oxygen content (C aO2) and O2-dependent signalling. This study investigated the impact of dehydration and concomitant alterations in C aO2 upon LBF and [Formula: see text]. Haemodynamics, arterial and femoral venous blood parameters and plasma [ATP] were measured at rest and during one-legged knee-extensor exercise in 7 males in four conditions: (1) control, (2) mild dehydration, (3) moderate dehydration, and (4) rehydration. Relative to control, C aO2 and LBF increased with dehydration at rest and during exercise (C aO2: from 199 ± 1 to 208 ± 2, and 202 ± 2 to 210 ± 2 ml L(-1) and LBF: from 0.38 ± 0.04 to 0.77 ± 0.09, and 1.64 ± 0.09 to 1.88 ± 0.1 L min(-1), respectively). Similarly, [Formula: see text] was unchanged or increased with dehydration at rest and during exercise, whereas arterial and leg perfusion pressures declined. Following rehydration, C aO2 declined (to 193 ± 2 mL L(-1)) but LBF remained elevated. Alterations in LBF were unrelated to C aO2 (r (2) = 0.13-0.27, P = 0.48-0.64) and plasma [ATP]. These findings suggest dehydration and concomitant alterations in C aO2 do not compromise LBF despite reductions in plasma [ATP]. While an additive or synergistic effect cannot be excluded, reductions in LBF during exercise with dehydration may not necessarily be associated with alterations in C aO2 and/or intravascular [ATP].

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

    PubMed

    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 < 0.0001), 0.5609 (adipose, P = 0.0008), and 0.0644 (free fluids, P = 0.3445). R(2) values for urine osmolality were 0.7760 (lean, P < 0.0001), 0.5005 (adipose, P = 0.0022), and 0.0568 (free fluids, P = 0.3739). These results suggest that non-imaging (1)H NMR methods are capable of non-invasively assessing dehydration in live animals.

  6. Dehydration of corneal anterior donor tissue with polyethylene glycol (PEG)-enriched media.

    PubMed

    Lie, Jessica T; Monnereau, Claire; Groeneveld-van Beek, Esther A; van der Wees, Jacqueline; Frank, Johannes; Bruinsma, Marieke; Melles, Gerrit R J

    2015-09-01

    Anterior donor grafts (including scleral rim, without Descemet membrane) increase in thickness and become hazy upon storage in organ culture (OC) medium. Transfer of these grafts to standard dehydration media just before transplantation does not reduce their thickness to normal. Therefore, we assessed the efficacy of different media enriched with polyethylene glycol (PEG) as dehydrating agents for organ-cultured anterior donor grafts. Grafts were harvested and stored in the commercial OC medium 'Max' (without dextran) for 1 week, and subsequently dehydrated in the standard commercial dehydration medium 'Jet' (with dextran) supplemented with 4-20% PEG3350, or 'Max' supplemented with 20% PEG6000 and PEG20.000, or 5-20% PEG35.000. Central corneal thickness (CCT), as assessed by anterior segment-optical coherence tomography, and transparency were evaluated before, and at 1, 4 and 7 days of dehydration. Transfer of grafts after 1 week of OC (average 1,200 µm) to 'Jet' supplemented with PEG3350 revealed a concentration-dependent effect of dehydration; CCT was restored to normal (500-600 µm) when 10% PEG3350 was added. However, transparency was only temporarily restored; after 1 day, the grafts turned hazy. In contrast, grafts transferred to 'Max' supplemented with 20% PEG35.000 were transparent throughout the evaluation period, but were dehydrated to beyond normal levels (average 300 µm). 'Max' supplemented with 5% PEG35.000 dehydrated grafts to normal values and restored transparency throughout. Thus, dehydration of anterior donor grafts prior to surgery in dextran-free OC medium supplemented with 5% PEG35.000 reduces graft thickness to normal and may facilitate anterior keratoplasty procedures.

  7. Bonding by Hydroxide-Catalyzed Hydration and Dehydration

    NASA Technical Reports Server (NTRS)

    Gwo, Dz-Hung

    2008-01-01

    A simple, inexpensive method for bonding solid objects exploits hydroxide-catalyzed hydration and dehydration to form silicate-like networks in thin surface and interfacial layers between the objects. The method can be practiced at room temperature or over a wide range of temperatures. The method was developed especially to enable the formation of precise, reliable bonds between precise optical components. The bonds thus formed exhibit the precision and transparency of bonds formed by the conventional optical-contact method and the strength and reliability of high-temperature frit bonds. The method also lends itself to numerous non-optical applications in which there are requirements for precise bonds and/or requirements for bonds, whether precise or imprecise, that can reliably withstand severe environmental conditions. Categories of such non-optical applications include forming composite materials, coating substrates, forming laminate structures, and preparing objects of defined geometry and composition. The method is applicable to materials that either (1) can form silicate-like networks in the sense that they have silicate-like molecular structures that are extensible into silicate-like networks or (2) can be chemically linked to silicate-like networks by means of hydroxide-catalyzed hydration and dehydration. When hydrated, a material of either type features surface hydroxyl (-OH) groups. In this method, a silicate-like network that bonds two substrates can be formed either by a bonding material alone or by the bonding material together with material from either or both of the substrates. Typically, an aqueous hydroxide bonding solution is dispensed and allowed to flow between the mating surfaces by capillary action. If the surface figures of the substrates do not match precisely, bonding could be improved by including a filling material in the bonding solution. Preferably, the filling material should include at least one ingredient that can be hydrated to

  8. Dehydration at the Tropical Tropopause Over the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Rohs, S.; Beuermann, J.; Gensch, I.; Kraemer, M.; MacKenzie, R.; Schiller, C.; Yushkov, V. A.

    2004-05-01

    During the APE-THESEO campaign in February/March 1999 high-resolution in-situ measurements were carried out onboard the Russian M-55 Geophysica high altitude aircraft, based on the Seychelles (-4.7° N, 55.3° E) in the western Indian Ocean. In the potential temperature range from 340 - 430 K, 36 individual (quasi)-vertical profiles of temperature, the gas-phase and total water cloud particles, and ozone were obtained. The height of the tropopause and the hygropause were highly variable for the investigated period. We attribute this to short and local perturbations to the seasonal cycle. The cold point tropopause was located at a potential temperature range from 365 - 403 K. Minimum temperatures were very low (183 - 194 K), leading to saturation mixing ratios at the tropopause of 1.1 - 8.4 ppmv. The hygropause was located on average 4 K above the tropopause with water vapour mixing ratios of 1.2 - 4.1 ppmv. These very low mixing ratios are comparable to those found in previous studies in the 'fountain region' over Micronesia. For 70 % of the vertical profiles, ice saturation was found in a wide range around the tropopause. Predominantly the saturation was corroborated by concurrently detected clouds up to the altitude of the cold point, providing evidence of active dehydration. We identify three common types of vertical profiles: coincident hygropause and cold point at relatively low potential temperatures, associated with a cirrus deck; coincident hygropause and cold point at relatively high potential temperatures, associated with thin subvisible cirrus; and unsaturated, cloud-free, profiles without a pronounced relationship between hygropause and cold point. Characteristics such as extension, number density, frequency distribution of relative humidity over ice of the cirrus clouds were different for these categories which allows to infer their different origin. The low water vapour ratios and the existence of saturation support the hypothesis that the Tropical

  9. Treatment of waste water in non-evaporating dehydration of low grade coal

    SciTech Connect

    Nakabayashi, Y.; Kamei, T.; Komai, K.; Kurihara, M.; Matsuura, Y.; Nakamura, A.; Shimotamari, A.; Wakabayashi, T.

    1983-07-26

    In a non-evaporating dehydration of brown coal, the coal is crushed and classified into lumps and fine particles. The lumps of coal are subjected to a non-evaporating dehydration in which waste water is produced. The waste water is contacted with the fine particles of coal so that components which affect the COD value of the water are absorbed by the coal particles. The coal particles are then burnt to produce saturated steam which is used in the non-evaporating dehydration.

  10. Intrarenal role of angiotensin II in controlling sodium excretion during dehydration in dogs.

    PubMed

    Trippodo, N C; Hall, J E; Lohmeier, T E; Guyton, A C

    1977-05-01

    1. The intrarenal role of angiotensin II in controlling sodium excretion was examined in anaesthetized, dehydrated dogs by infusing the angiotensin II antagonist Sar1-Ile8-angiotensin II directly into the renal artery. Comparisons were made with dehydrated dogs receiving only sodium chloride solution intrarenally. 2. Intrarenal angiotensin II blockade resulted in significant increases in urinary sodium excretion and urine flow rate. 3. The results indicate that during the high-renin state of dehydration endogenous angiotensin II has intrarenal effects which lead to salt and water retention.

  11. Freeze avoidance: a dehydrating moss gathers no ice.

    PubMed

    Lenné, Thomas; Bryant, Gary; Hocart, Charles H; Huang, Cheng X; Ball, Marilyn C

    2010-10-01

    Using cryo-SEM with EDX fundamental structural and mechanical properties of the moss Ceratodon purpureus (Hedw.) Brid. were studied in relation to tolerance of freezing temperatures. In contrast to more complex plants, no ice accumulated within the moss during the freezing event. External ice induced desiccation with the response being a function of cell type; water-filled hydroid cells cavitated and were embolized at -4 °C while parenchyma cells of the inner cortex exhibited cytorrhysis, decreasing to ∼ 20% of their original volume at a nadir temperature of -20 °C. Chlorophyll fluorescence showed that these winter acclimated mosses displayed no evidence of damage after thawing from -20 °C while GCMS showed that sugar concentrations were not sufficient to confer this level of freezing tolerance. In addition, differential scanning calorimetry showed internal ice nucleation occurred in hydrated moss at ∼-12 °C while desiccated moss showed no evidence of freezing with lowering of nadir temperature to -20 °C. Therefore the rapid dehydration of the moss provides an elegantly simple solution to the problem of freezing; remove that which freezes.

  12. Experimental investigation of bioethanol liquid phase dehydration using natural clinoptilolite.

    PubMed

    Karimi, Samira; Ghobadian, Barat; Omidkhah, Mohammad-Reza; Towfighi, Jafar; Tavakkoli Yaraki, Mohammad

    2016-05-01

    An experimental study of bioethanol adsorption on natural Iranian clinoptilolite was carried out. Dynamic breakthrough curves were used to investigate the best adsorption conditions in bioethanol liquid phase. A laboratory setup was designed and fabricated for this purpose. In order to find the best operating conditions, the effect of liquid pressure, temperature and flow rate on breakthrough curves and consequently, maximum ethanol uptake by adsorbent were studied. The effects of different variables on final bioethanol concentration were investigated using Response Surface Methodology (RSM). The results showed that by working at optimum condition, feed with 96% (v/v) initial ethanol concentration could be purified up to 99.9% (v/v). In addition, the process was modeled using Box-Behnken model and optimum operational conditions to reach 99.9% for final ethanol concentration were found equal to 10.7 °C, 4.9 bar and 8 mL/min for liquid temperature, pressure and flow rate, respectively. Therefore, the selected natural Iranian clinoptilolite was found to be a promising adsorbent material for bioethanol dehydration process.

  13. Onion and garlic dehydration in the San Emidio Desert, Nevada

    SciTech Connect

    Lund, J.W.; Lienau, P.J.

    1994-07-01

    Integrated Ingredients dedicated their new onion and garlic processing plant on May 25th. {open_quotes}Grunion{close_quotes} as the new community of 72 employees has been labeled, is located just south of Empire and Gerlach and about 100 miles north of Reno, Nevada. The plant, run by Integrated Ingredients (based in Alameda, CA), is a division of Burns Philp Food, Inc., which owns brands such as Spice Islands, Durkee-French and Fleischmann`s. This plant gives the company the ability to produce its own products for industrial and consumer markets instead of purchasing them. The plant was located in the San Emidio Desert at the edge of the vast Black Rock Desert and the Great Basin to take advantage of the high temperature geothermal resource (approximately 270{degrees}F). The resource is also used by the OESI/AMOR II 3.6 MW binary plant about a mile south of the dehydration plant and a gold heap leaching operation just to the north of the plant (Wind Mt. mine operated by AMAX). In addition to the geothermal energy, the high desert is an ideal location for onion and garlic processing because the cold winters kill damaging microbes. Dry winters and summers also help.

  14. Experimental investigation of bioethanol liquid phase dehydration using natural clinoptilolite

    PubMed Central

    Karimi, Samira; Ghobadian, Barat; Omidkhah, Mohammad-Reza; Towfighi, Jafar; Tavakkoli Yaraki, Mohammad

    2016-01-01

    An experimental study of bioethanol adsorption on natural Iranian clinoptilolite was carried out. Dynamic breakthrough curves were used to investigate the best adsorption conditions in bioethanol liquid phase. A laboratory setup was designed and fabricated for this purpose. In order to find the best operating conditions, the effect of liquid pressure, temperature and flow rate on breakthrough curves and consequently, maximum ethanol uptake by adsorbent were studied. The effects of different variables on final bioethanol concentration were investigated using Response Surface Methodology (RSM). The results showed that by working at optimum condition, feed with 96% (v/v) initial ethanol concentration could be purified up to 99.9% (v/v). In addition, the process was modeled using Box–Behnken model and optimum operational conditions to reach 99.9% for final ethanol concentration were found equal to 10.7 °C, 4.9 bar and 8 mL/min for liquid temperature, pressure and flow rate, respectively. Therefore, the selected natural Iranian clinoptilolite was found to be a promising adsorbent material for bioethanol dehydration process. PMID:27222748

  15. A study of dielectric anisotropy in dehydrated cortical bone.

    PubMed

    García Sánchez, F J; De Mercato, G

    The complex permittivity of dehydrated bovine femoral bone has been studied in vitro, in the three orthogonal directions from 1 kHz to 3 MHz, as part of an analysis of the various factors involved in the dielectric behavior of fluid-saturated cortical bone. In this study the bone's physical structure reveals its anisotropic nature by its dependence on both the real and imaginary parts of permittivity on the orientation of the applied electric field. The real permittivity and the total conductivity are generally higher in the longitudinal direction than in the other two transverse directions, with the tangential direction presenting values between those of the longitudinal and radial directions and closer to the former. The high frequency limit of the real part of the permittivity was found to be around 10 and its low frequency limit is of the order of 1000. The dispersion parameters of relaxation time show values of about 0.4 and the corresponding mean relaxation frequencies are below 100 Hz.

  16. Dehydrating and Sterilizing Wastes Using Supercritical CO2

    NASA Technical Reports Server (NTRS)

    Brown, Ian J.

    2006-01-01

    A relatively low-temperature process for dehydrating and sterilizing biohazardous wastes in an enclosed life-support system exploits (1) the superior mass-transport properties of supercritical fluids in general and (2) the demonstrated sterilizing property of supercritical CO2 in particular. The wastes to be treated are placed in a chamber. Liquid CO2, drawn from storage at a pressure of 850 psi (approx.=5.9 MPa) and temperature of 0 C, is compressed to pressure of 2 kpsi (approx.=14 MPa) and made to flow into the chamber. The compression raises the temperature to 10 C. The chamber and its contents are then further heated to 40 C, putting the CO2 into a supercritical state, in which it kills microorganisms in the chamber. Carrying dissolved water, the CO2 leaves the chamber through a back-pressure regulator, through which it is expanded back to the storage pressure. The expanded CO2 is refrigerated to extract the dissolved water as ice, and is then returned to the storage tank at 0 C

  17. Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter

    NASA Technical Reports Server (NTRS)

    Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoeberl, M. R.; Elkins, J. W.; Wamsley, P. R.; Dutton, G. S.; Bui, T. P.; Kohn, D. W.; Anderson, J. G.

    1998-01-01

    Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (theta about 450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NO(sub y)) had also been removed, with layers of enhanced (sub y) at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (about 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 micron) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range of theta is estimated to have been dehydrated in this event.

  18. Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter

    NASA Technical Reports Server (NTRS)

    Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoerberl, M. R.; Elkins, J. W.; Wamsley, P. R.

    1998-01-01

    Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (theta = 450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NOy) had also been removed, with layers of enhanced NOy at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (approx. 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 micrometers) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range of theta is estimated to have been dehydrated in this event.

  19. Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter

    NASA Technical Reports Server (NTRS)

    Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoeberl, M. R.; Elkins, J. W.; Wamsley, P. R.; Dutton, G. S.; Bui, T. P.; Kohn, D. W.; Anderson, J. G.

    1998-01-01

    Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (0-450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NO(y)) had also been removed, with layers of enhanced NO(y) at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (approximately 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 microns) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range of 0 is estimated to have been dehydrated in this event.

  20. Liquid-phase and vapor-phase dehydration of organic/water solutions

    DOEpatents

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

    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.

  1. Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter

    NASA Technical Reports Server (NTRS)

    Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoeberl, M. R.; Elkins, J. W.; Wamsley, P. R.; Dutton, G. S.; Bui, T. P.; Kohn, D. W.; Anderson, J. G.

    1998-01-01

    Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (theta approximately 450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NO(y)) had also been removed, with layers of enhanced NO(y) at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (approximately 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 micrometers) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range Transport of theta is estimated to have been dehydrated in this event.

  2. Elastic and structural properties of zeolites: Sodalite and dehydrated zeolite A

    SciTech Connect

    Kim, S.; Keskar, N.R.; McCormick, A.V.; Chelikowsky, J.R.; Davis, H.T.

    1995-06-01

    A pairwise interatomic potential has been used to investigate elastic and structural properties of two cubic zeolites: sodalite and dehydrated zeolite A. Constant volume energy minimization has been used to determine the variation of lattice constants and atomic coordinates with pressure. The calculated structures of sodalite and dehydrated zeolite A obtained at zero pressure are in reasonably good agreement with the available experimental values. We find that the structures at zero pressure are largely determined by the Coulomb potential. The pressure dependence of bond lengths and bond angles show that both sodalite and dehydrated zeolite A are easily deformed by bending the Si--O--Al angles. As expected for a less dense crystal, the dehydrated zeolite A is softer than the sodalite. We have also obtained the equation of state of these materials.

  3. Dehydration-induced conformational transitions in proteins and their inhibition by stabilizers.

    PubMed Central

    Prestrelski, S J; Tedeschi, N; Arakawa, T; Carpenter, J F

    1993-01-01

    Dehydration of proteins results in significant, measurable conformational changes as observed using Fourier-transform infrared spectroscopy and resolution-enhancement techniques. For several proteins these conformational changes are at least partially irreversible, since, upon rehydration, denaturation and aggregation are observed. The presence of certain stabilizers inhibited these dehydration-induced transitions; the native structure was preserved in the dried state and upon reconstitution. Conformational transitions were also observed in a model polypeptide, poly-L-lysine, after lyophilization and were inhibited with the addition of stabilizing cosolutes. The ability of a particular additive to preserve the aqueous structure of dehydrated proteins and poly-L-lysine upon dehydration correlates directly with its ability to preserve the activity of lactate dehydrogenase, a labile enzyme, during drying. PMID:7693001

  4. A NOVEL HYDROPHILIC POLYMER MEMBRANE FOR THE DEHYDRATION OF ORGANIC SOLVENTS

    EPA Science Inventory

    Novel hydrophilic polymer membranes based on polyallylamine ydrochloride- polyvinylalcohol are developed. The high selectivity and flux characteristics of these membranes for the dehydration of organic solvents are evaluated using pervaporation technology and are found to be ver...

  5. Energy Efficient Hybrid Vapor Stripping-Vapor Permeation Process for Ethanol Recovery ad Dehydration

    EPA Science Inventory

    Distillation combined with molecular sieve dehydration is the current state of the art for fuel grade ethanol production from fermentation broths. To improve the sustainability of bioethanol production, energy efficient separation alternatives are needed, particularly for lower f...

  6. Membrane-based recovery and dehydration of alcohols from fermentation broths - of materials and modules

    EPA Science Inventory

    Distillation combined with molecular sieve dehydration is the current state of the art for fuel grade ethanol production from fermentation broths. As the liquid biofuels industry transitions to lignocellulosic feedstocks, expands the end product portfolio to include other alcoho...

  7. Energy efficient recovery and dehydration of ethanol from fermentation broths by Membrane Assisted Vapor Stripping technology

    EPA Science Inventory

    Distillation combined with molecular sieve dehydration is the current state of the art for fuel grade ethanol production from fermentation broths. To improve the sustainability of bioethanol production, energy efficient separation alternatives are needed, particularly for lower ...

  8. Mixed Matrix Silicone and Fluorosilicone/Zeolite 4A Membranes for Ethanol Dehydration by Pervaporation

    EPA Science Inventory

    The ability of homogeneous and mixed matrix membranes prepared using standard silicone rubber, poly(dimethylsiloxane) (PDMS), and fluorosilicone rubber, poly(trifluoropropylmethylsiloxane) (PTFPMS), to dehydrate ethanol by pervaporation was evaluated. Although PDMS is generally c...

  9. Dehydration rate determines the degree of membrane damage and desiccation tolerance in bryophytes.

    PubMed

    Cruz de Carvalho, Ricardo; Catalá, Myriam; Branquinho, Cristina; Marques da Silva, Jorge; Barreno, Eva

    2017-03-01

    Desiccation tolerant (DT) organisms are able to withstand an extended loss of body water and rapidly resume metabolism upon rehydration. This ability, however, is strongly dependent on a slow dehydration rate. Fast dehydration affects membrane integrity leading to intracellular solute leakage upon rehydration and thereby impairs metabolism recovery. We test the hypothesis that the increased cell membrane damage and membrane permeability observed under fast dehydration, compared with slow dehydration, is related to an increase in lipid peroxidation. Our results reject this hypothesis because following rehydration lipid peroxidation remains unaltered, a fact that could be due to the high increase of NO upon rehydration. However, in fast-dried samples we found a strong signal of red autofluorescence upon rehydration, which correlates with an increase in ROS production and with membrane leakage, particularly the case of phenolics. This could be used as a bioindicator of oxidative stress and membrane damage.

  10. Effect of simultaneous infrared dry-blanching and dehydration on quality characteristics of carrot slices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the effects of various processing parameters on carrot slices exposed to infrared (IR) radiation heating for achieving simultaneous infrared dry-blanching and dehydration (SIRDBD). The investigated parameters were product surface temperature, slice thickness and processing ti...

  11. Effect of pre-dehydration treatment on the in vitro digestibility of starch in cookie.

    PubMed

    Kawai, Kiyoshi; Kawai, Haruna; Tomoda, Yuka; Matsusaki, Keiko; Hagura, Yoshio

    2012-12-01

    In order to understand the effect of pre-dehydration on the in vitro digestibility of cookie starch, cookie dough samples were dehydrated by vacuum treatment, and melting temperature (T(m)) of the crystalline amylopectin in the dough, internal temperature and water content of the dough during baking, and non-hydrolysed starch content of the obtained cookies were investigated. The T(m) of crystalline amylopectin increased with decreased water content of the dough, and the result was described as a T(m)-curve. The internal temperature of non-dehydrated dough surpassed the T(m)-curve during baking. Pre-dehydrated dough, on the other hand, always indicated a lower internal temperature than the T(m)-curve. The non-hydrolysed starch content obtained under a given condition increased significantly with a decrease in the initial water content of cookies. This will be because the melting of crystalline amylopectin was prevented, at least partially, during baking.

  12. Long-Term Storage Studies on Dehydrated Ration Items and Food Packets

    DTIC Science & Technology

    1976-06-01

    CLASSIFICATION Of THIS f»AGeprh«n D«# Bnffd) At 100°F, storage life of cheese spread, pineapple, beef stew, chocolate brownies, and fruitcake was 12...beef steak, beef stew, frankfurters, fruitcake, pineapple, and chocolate covorad brownies and cheese spread. Freeze dehydrated ration items from... chocolate brownies .... 35 36 temperature and duration of storage on freeze dehydrated chicken stew ....... 37 temperature and duration of storage

  13. Dehydration, rehydration, and overhydration alter patterns of gene expression in the Antarctic midge, Belgica antarctica.

    PubMed

    Lopez-Martinez, Giancarlo; Benoit, Joshua B; Rinehart, Joseph P; Elnitsky, Michael A; Lee, Richard E; Denlinger, David L

    2009-05-01

    We investigated molecular responses elicited by three types of dehydration (fast, slow and cryoprotective), rehydration and overhydration in larvae of the Antarctic midge, Belgica antarctica. The larvae spend most the year encased in ice but during the austral summer are vulnerable to summer storms, osmotic stress from ocean spray and drying conditions due to wind and intense sunlight. Using suppressive subtractive hybridization (SSH), we obtained clones that were potentially responsive to dehydration and then used northern blots to evaluate the gene's responsiveness to different dehydration rates and hydration states. Among the genes most responsive to changes in the hydration state were those encoding heat shock proteins (smHsp, Hsp70, Hsp90), antioxidants (superoxide dismutase, catalase), detoxification (metallothionein, cytochrome p450), genes involved in altering cell membranes (fatty acid desaturase, phospholipase A2 activating protein, fatty acyl CoA desaturase) and the cytoskeleton (actin, muscle-specific actin), and several additional genes including a zinc-finger protein, pacifastin and VATPase. Among the three types of dehydration evaluated, fast dehydration elicited the strongest response (more genes, higher expression), followed by cryoprotective dehydration and slow dehydration. During rehydration most, but not all, genes that were expressed during dehydration continued to be expressed; fatty acid desaturase was the only gene to be uniquely upregulated in response to rehydration. All genes examined, except VATPase, were upregulated in response to overhydration. The midge larvae are thus responding quickly to water loss and gain by expressing genes that encode proteins contributing to maintenance of proper protein function, protection and overall cell homeostasis during times of osmotic flux, a challenge that is particularly acute in this Antarctic environment.

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

    PubMed

    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.

  15. Formation of Linear Polyenes in Thermal Dehydration of Polyvinyl Alcohol, Catalyzed by Phosphotungstic Acid

    NASA Astrophysics Data System (ADS)

    Tretinnikov, O. N.; Sushko, N. I.

    2015-01-01

    In order to obtain linear polyenes in polyvinyl alcohol films via acid-catalyzed thermal dehydration of the polyvinyl alcohol, we used phosphotungstic acid as the catalyst: a safe and heat-stable solid chemical compound. We established that phosphotungstic acid, introduced as solid nanoparticles into polyvinyl alcohol films, is a more effective dehydration catalyst than hydrochloric acid, since in contrast to HCl it does not evaporate from the film during heat treatment.

  16. Repeated bouts of dehydration deplete nutrient reserves and reduce egg production in the mosquito Culex pipiens

    PubMed Central

    Benoit, Joshua B.; Patrick, Kevin R.; Desai, Karina; Hardesty, Jeffrey J.; Krause, Tyler B.; Denlinger, David L.

    2010-01-01

    In this study of the mosquito, Culex pipiens, we examined the impact of multiple bouts of dehydration and rehydration on survival, depletion of metabolic reserves and egg production in both non-diapausing and diapausing females. Mosquitoes provided with access to sugar during rehydration survived longer than those allowed to rehydrate without sugar, and their survival was similar to that of mosquitoes of the same age that were not dehydrated. Among mosquitoes not provided with sugar, each dehydration bout reduced the mosquito's dry mass – an effect likely to be due to the utilization of carbohydrates and lipid reserves. The toll on glycogen and lipid reserves is likely to be especially costly for diapausing mosquitoes that are dependent on these stored reserves for winter survival. Egg production in both non-diapausing and post-diapausing C. pipiens was also reduced in response to multiple bouts of dehydration. Although egg quality was not compromised, the number of eggs produced was reduced. Both non-diapausing and diapausing females can compensate for the nutrient loss due to dehydration by sugar feeding but the opportunity to feed on sugar is likely to be rarely available in the overwintering habitat of diapausing females, thus the impact of dehydration may be especially pronounced in overwintering populations of C. pipiens. PMID:20675546

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

    PubMed

    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.

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

    PubMed

    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.

  19. Application of anhydrobiosis and dehydration of yeasts for non-conventional biotechnological goals.

    PubMed

    Rapoport, Alexander; Turchetti, Benedetta; Buzzini, Pietro

    2016-06-01

    Dehydration of yeast cells causes them to enter a state of anhydrobiosis in which their metabolism is temporarily and reversibly suspended. This unique state among organisms is currently used in the production of active dry yeasts, mainly used in baking and winemaking. In recent decades non-conventional applications of yeast dehydration have been proposed for various modern biotechnologies. This mini-review briefly summarises current information on the application of dry yeasts in traditional and innovative fields. It has been shown that dry yeast preparations can be used for the efficient protection, purification and bioremediation of the environment from heavy metals. The high sorption activity of dehydrated yeasts can be used as an interesting tool in winemaking due to their effects on quality and taste. Dry yeasts are also used in agricultural animal feed. Another interesting application of yeast dehydration is as an additional stage in new methods for the stable immobilisation of microorganisms, especially in cases when biotechnologically important strains have no affinity with the carrier. Such immobilisation methods also provide a new approach for the successful conservation of yeast strains that are very sensitive to dehydration. In addition, the application of dehydration procedures opens up new possibilities for the use of yeast as a model system. Separate sections of this review also discuss possible uses of dry yeasts in biocontrol, bioprotection and biotransformations, in analytical methods as well as in some other areas.

  20. Protein dynamics in thylakoids of the desiccation-tolerant plant Boea hygroscopica during dehydration and rehydration.

    PubMed

    Navari-Izzo, F; Quartacci, M F; Pinzino, C; Rascio, N; Vazzana, C; Sgherri, C L

    2000-11-01

    Plants of Boea hygroscopica F. Muell were dehydrated to 9% relative water content (RWC) by withholding water for 26 d, and afterward the plants were rehydrated. Leaves were taken from control plants after 7, 12, and 26 d from the beginning of dehydration, and after 6 and 48 h from rehydration. The RWC decreased by 80% during dehydration, but the leaves regained RWC with rehydration. Dehydrated plants showed lesser amounts of proteins, lipids, and chlorophyll, all of which increased following rewatering. The lipid-to-protein ratio, which decreased during dehydration, returned to control level after 48 h of rehydration. Thylakoid lipids were more unsaturated when RWC reached the value of 9%. EPR measurements of spin-labeled proteins showed the presence of three different groups of proteins with different mobility in thylakoid membranes. The rotational correlation time of groups 1 and 2 increased with dehydration and decreased upon rehydration, whereas group 3 showed little changes. Desiccation did not cause thylakoid swelling or breakage, but the membrane system assemblage showed changes in thylakoid stacking. After 48 h of rehydration the membrane system recovered completely the organization of the fully hydrated state, showing several well-defined and regularly distributed grana.

  1. Gene expression changes governing extreme dehydration tolerance in an Antarctic insect.

    PubMed

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

    2012-12-11

    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.

  2. Buffering and inhibition of glycol in gas dehydration applications: An alternative to amines

    SciTech Connect

    Stefl, B.A.; Bosen, S.F.

    1997-02-01

    Corrosion in gas dehydration systems can be attributed to many factors, including chloride intrusion, acid gas absorption, and glycol degradation. Inhibition systems for glycol dehydration systems must incorporate corrosion inhibition and buffering using stable, nonscaling, and nondepleting additives. Traditional amine treatments are unstable in gas streams containing carbon dioxide. An alternative inhibitor technology was tested in three field test programs under various dehydration conditions. Traditional nitrite, molybdate, and amine inhibitors were tested in combination with the alternative technology. Uninhibited and amine inhibited control units were included. Corrosion rates and dehydration fluid chemistries were monitored. Field tests demonstrated effectiveness of the nonamine-based technology in reducing corrosion rates and maintaining alkalinity of the glycol dehydration fluid. Corrosion rates at the reboiler in systems treated with the alternative technology averaged 10 times less than the average rate in control units and had a substantially lower incidence of localized corrosion. The pH of the treated glycol stayed alkaline throughout the testing, varying within 0.85 pH units. Corresponding control units showed wide swings in pH, ranging from an acidic 4.1 to an alkaline 10.3. No operational difficulties, including foaming, inadequate drying, or excess glycol loss, were experienced in the treated dehydration units. Testing of the alternative technology in combination with traditional technologies revealed no significant benefits over the alternative technology alone. However, the alternate technology showed significant improvements in corrosion control and stability over traditional amine inhibition.

  3. Ultrastructural, physiological and proteomic analysis of Nostoc flagelliforme in response to dehydration and rehydration.

    PubMed

    Liang, Wenyu; Zhou, Youwen; Wang, Lingxia; You, Xiangrong; Zhang, Yaping; Cheng, Chi-Lien; Chen, Wei

    2012-10-22

    Nostoc flagelliforme must undergo a dehydration/rehydration cycle during its growth stages; the mechanisms underlying this constraint are examined. The novel insights into N. flagelliforme's response to desiccation and rehydration at ultrastructural, physiological and proteomic levels were offered. The structure of colonies and cells remained unchanged in response to dehydration and rehydration treatments except that the sheath appeared shrunken, and both the quantity and volume of vacuoles were decreased when dehydrated compared with rehydration. A significant increase in photosynthesis, respiration, total Rubisco activity, superoxide anion level, SOD, CAT, POD, nitrogenase and glutamine synthetase (GS) activities in response to rehydration was noted, whereas H(2)O(2), ammonium, proline and glutamate contents all registered a decrease. 32 differentially expressed proteins between dehydrated and rehydrated colonies were categorized according to their predicted functions into secretion, signaling, transcription and translation, antioxidative processes, nitrogen metabolism, energy metabolism, lipid metabolism and chaperonin. The dehydration is a quiescent state in which metabolism is down-regulated, upon rehydration, a metabolic shift occurs from quiescent to active. The specific metabolic and regulated mechanisms to accommodate the dehydration/rehydration cycle in N. flagelliforme is reported here.

  4. Organ Specific Proteomic Dissection of Selaginella bryopteris Undergoing Dehydration and Rehydration

    PubMed Central

    Deeba, Farah; Pandey, Ashutosh K.; Pandey, Vivek

    2016-01-01

    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 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. PMID:27092152

  5. Gene expression changes governing extreme dehydration tolerance in an Antarctic insect

    PubMed Central

    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

  6. Early Transcriptional Response of Soybean Contrasting Accessions to Root Dehydration

    PubMed Central

    Ferreira Neto, José Ribamar Costa; Pandolfi, Valesca; Guimaraes, Francismar Corrêa Marcelino; Benko-Iseppon, Ana Maria; Romero, Cynara; Silva, Roberta Lane de Oliveira; Rodrigues, Fabiana Aparecida; Abdelnoor, Ricardo Vilela; Nepomuceno, Alexandre Lima; Kido, Ederson Akio

    2013-01-01

    Drought is a significant constraint to yield increase in soybean. The early perception of water deprivation is critical for recruitment of genes that promote plant tolerance. DeepSuperSAGE libraries, including one control and a bulk of six stress times imposed (from 25 to 150 min of root dehydration) for drought-tolerant and sensitive soybean accessions, allowed to identify new molecular targets for drought tolerance. The survey uncovered 120,770 unique transcripts expressed by the contrasting accessions. Of these, 57,610 aligned with known cDNA sequences, allowing the annotation of 32,373 unitags. A total of 1,127 unitags were up-regulated only in the tolerant accession, whereas 1,557 were up-regulated in both as compared to their controls. An expression profile concerning the most representative Gene Ontology (GO) categories for the tolerant accession revealed the expression “protein binding” as the most represented for “Molecular Function”, whereas CDPK and CBL were the most up-regulated protein families in this category. Furthermore, particular genes expressed different isoforms according to the accession, showing the potential to operate in the distinction of physiological behaviors. Besides, heat maps comprising GO categories related to abiotic stress response and the unitags regulation observed in the expression contrasts covering tolerant and sensitive accessions, revealed the unitags potential for plant breeding. Candidate genes related to “hormone response” (LOX, ERF1b, XET), “water response” (PUB, BMY), “salt stress response” (WRKY, MYB) and “oxidative stress response” (PER) figured among the most promising molecular targets. Additionally, nine transcripts (HMGR, XET, WRKY20, RAP2-4, EREBP, NAC3, PER, GPX5 and BMY) validated by RT-qPCR (four different time points) confirmed their differential expression and pointed that already after 25 minutes a transcriptional reorganization started in response to the new condition, with

  7. Selective Brain Cooling Reduces Water Turnover in Dehydrated Sheep

    PubMed Central

    Strauss, W. Maartin; Hetem, Robyn S.; Mitchell, Duncan; Maloney, Shane K.; Meyer, Leith C. R.; Fuller, Andrea

    2015-01-01

    In artiodactyls, arterial blood destined for the brain can be cooled through counter-current heat exchange within the cavernous sinus via a process called selective brain cooling. We test the hypothesis that selective brain cooling, which results in lowered hypothalamic temperature, contributes to water conservation in sheep. Nine Dorper sheep, instrumented to provide measurements of carotid blood and brain temperature, were dosed with deuterium oxide (D2O), exposed to heat for 8 days (40◦C for 6-h per day) and deprived of water for the last five days (days 3 to 8). Plasma osmolality increased and the body water fraction decreased over the five days of water deprivation, with the sheep losing 16.7% of their body mass. Following water deprivation, both the mean 24h carotid blood temperature and the mean 24h brain temperature increased, but carotid blood temperature increased more than did brain temperature resulting in increased selective brain cooling. There was considerable inter-individual variation in the degree to which individual sheep used selective brain cooling. In general, sheep spent more time using selective brain cooling, and it was of greater magnitude, when dehydrated compared to when they were euhydrated. We found a significant positive correlation between selective brain cooling magnitude and osmolality (an index of hydration state). Both the magnitude of selective brain cooling and the proportion of time that sheep spent selective brain cooling were negatively correlated with water turnover. Sheep that used selective brain cooling more frequently, and with greater magnitude, lost less water than did conspecifics using selective brain cooling less efficiently. Our results show that a 50kg sheep can save 2.6L of water per day (~60% of daily water intake) when it employs selective brain cooling for 50% of the day during heat exposure. We conclude that selective brain cooling has a water conservation function in artiodactyls. PMID:25675092

  8. Alteration and Dehydration in the Parent Asteroid of Allende

    NASA Astrophysics Data System (ADS)

    Krot, A. N.; Scott, E. R. D.; Zolensky, M. E.

    1995-09-01

    CV3 chondrites experienced various degrees of late-stage modification, including: fayalitic rims around forsteritic grains, secondary mineralization (e.g., nepheline, sodalite, magnetite) in CAIs and chondrules, and formation of phyllosilicates [1]. Our literature survey show that these secondary features probably have a related origin [2]. Although an asteroidal origin is generally accepted for most phyllosilicates [3] and proposed for magnetite [4], the other secondary features have been attributed to reactions of CV3 components with a hot (> 1500 K) and oxidized (H2O/H2 about 1) nebular gas [5]. The Allende meteorite is considered to be a primitive CV3, because phyllosilicates are absent in the matrix and metamorphic effects are not apparent [6]. However, all other secondary features are well-developed. Studies of dark inclusions (DIs) in CV3s [7] provide a key to understanding the secondary features in Allende. Mineralogical, chemical and isotopic data indicate that DIs and CV3s have related origins. Matrices of the DIs resemble the Allende matrix, but the chondrules show a wider range of alteration textures. In some DIs, the chondrules have only fayalitic rims like those in Allende, but in others there are chondrule-shaped regions of porous fayalitic olivine. In DIs of intermediate type, the chondrules consist of forsteritic cores, which have fayalitic rims, surrounded by porous fayalitic olivine. We conclude that the sequence observed among DIs reflects various degrees of replacement of chondrules by fayalitic olivine. The presence of veins of fayalitic olivine, nepheline and Ca-pyroxene throughout DIs [7] which experienced the most pervasive alteration argues for asteroidal processing of DIs. Like Kojima and Tomeoka [7], we infer that porous fayalitic olivine formed by metamorphic dehydration of phyllosilicates on an asteroid. We suggest that the Allende host and Allende-like DIs represent the initial stages of the alteration sequence from material similar

  9. Permeability control on transient slip weakening during gypsum dehydration: Implications for earthquakes in subduction zones

    NASA Astrophysics Data System (ADS)

    Leclère, Henri; Faulkner, Daniel; Wheeler, John; Mariani, Elisabetta

    2016-05-01

    A conflict has emerged from recent laboratory experiments regarding the question of whether or not dehydration reactions can promote unstable slip in subduction zones leading to earthquakes. Although reactions produce mechanical weakening due to pore-fluid pressure increase, this weakening has been associated with both stable and unstable slip. Here, new results monitoring strength, permeability, pore-fluid pressure, reaction progress and microstructural evolution during dehydration reactions are presented to identify the conditions necessary for mechanical instability. Triaxial experiments are conducted using gypsum and a direct shear sample assembly with constant normal stress that allows the measurement of permeability during sliding. Tests are conducted with temperature ramp from 70 to 150 °C and with different effective confining pressures (50, 100 and 150 MPa) and velocities (0.1 and 0.4 μm s-1). Results show that gypsum dehydration to bassanite induces transient stable-slip weakening that is controlled by pore-fluid pressure and permeability evolution. At the onset of dehydration, the low permeability promoted by pore compaction induces pore-fluid pressure build-up and stable slip weakening. The increase of bassanite content during the reaction shows clear evidence of dehydration related with the development of R1 Riedel shears and P foliation planes where bassanite is preferentially localized along these structures. The continued production of bassanite, which is stronger than gypsum, provides a supporting framework for newly formed pores, thus resulting in permeability increase, pore-fluid pressure drop and fault strength increase. After dehydration reaction, deformation is characterized by unstable slip on the fully dehydrated reaction product, controlled by the transition from velocity-strengthening to velocity-weakening behaviour of bassanite at temperature above ∼140 °C and the localization of deformation along narrow Y-shear planes. This study

  10. Effect of acute mild dehydration on cognitive-motor performance in golf.

    PubMed

    Smith, Mark F; Newell, Alex J; Baker, Mistrelle R

    2012-11-01

    Whether mild dehydration (-1 to 3% body mass change [ΔBM]) impairs neurophysiological function during sport-specific cognitive-motor performance has yet to be fully elucidated. To investigate this within a golfing context, 7 low-handicap players (age: 21 ± 1.1 years; mass: 76.1 ± 11.8 kg; stature: 1.77 ± 0.07 m; handicap: 3.0 ± 1.2) completed a golf-specific motor and cognitive performance task in a euhydrated condition (EC) and dehydrated condition (DC) (randomized counterbalanced design; 7-day interval). Dehydration was controlled using a previously effective 12-hour fluid restriction, monitored through ΔBM and urine color assessment (UCOL). Mild dehydration reduced the mean BM by 1.5 ± 0.5% (p = 0.01), with UCOL increasing from 2 (EC) to 4 (DC) (p = 0.02). Mild dehydration significantly impaired motor performance, expressed as shot distance (114.6 vs. 128.6 m; p < 0.001) and off-target accuracy (7.9 vs. 4.1 m; p = 0.001). Cognitive performance, expressed as the mean error in distance judgment to target increased from 4.1 ± 3.0 m (EC) to 8.8 ± 4.7 m (DC) (p < 0.001). The findings support those of previous research that indicates mild dehydration (-1 to 2% ΔBM) significantly impairs cognitive-motor task performance. This study is the first to show that mild dehydration can impair distance, accuracy, and distance judgment during golf performance.

  11. Dehydration triggers differential microRNA expression in Xenopus laevis brain.

    PubMed

    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.

  12. Dehydration and drinking behavior of the marine file snake Acrochordus granulatus.

    PubMed

    Lillywhite, Harvey B; Heatwole, Harold; Sheehy, Coleman M

    2014-01-01

    Dehydration and drinking behaviors were investigated in the little file snake (Acrochordus granulatus) collected from marine populations in the Philippines and in Australia. File snakes dehydrate in seawater and do not drink seawater when dehydrated in air and offered seawater to drink. Dehydrated file snakes drink freshwater, and the threshold of dehydration for first drinking response is a deficit of -7.4% ± 2.73% (mean ± SD) of original body mass. The thirst mechanism in this species is more sensitive than that recently studied in sea snakes. The volume of water ingested increases with increasing dehydration. Mean plasma osmolality was 278.89 ± 33.17 mMol/kg, mean hematocrit was 59% ± 5.45%, and both decreased in snakes that drank freshwater following acclimation in seawater. Snakes always drank freshwater at the water's surface, testing water with tongue flicks between each swallowing of water. Some snakes ingested large volumes of freshwater, approaching 50% of body mass. Visual observations and measurements of osmolality in plasma and stomach fluids suggest that water is taken up from the gut and dilutes body fluids slowly over the course of 48 h or longer. Eighty percent of snakes that were collected during the dry season (following >4 mo of drought) in Australia drank freshwater immediately following their capture, indicating that snakes were dehydrated in their marine environment even when known to have been feeding at the time. Snakes kept in seawater maintained a higher state of body condition when freshwater was periodically available. These results support a growing conclusion that diverse taxa of marine snakes require environmental sources of freshwater to maintain water balance, contrary to earlier belief. Identifying the freshwater requirements of secondarily marine vertebrates is important for better understanding how they maintain water balance in marine habitats, especially with respect to conservation in changing environments.

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

    PubMed

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

    2016-10-06

    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 post-training/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 to 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 to 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.

  14. Correlation of rock dehydration and dynamic micro state-rate friction law to coseismic fault

    NASA Astrophysics Data System (ADS)

    Zhu, B.; Shi, Y.

    2011-12-01

    In this paper, the relationship between the coseismic fault rock dehydration and micro state-rate friction law have been explored at multi temporal scales level by using hybrid hypersingular integral equation & Lattice Boltzmann method (HHIE-LBM) under parallel CPU and GPU platform. First, seven standard rock specimens from Continental Scientific Drilling Project in China were studied. Based on the micro tomography technology, digital restructure technology and first principle, molecular scale (10nm) virtual modules, micro crystal scale (30~50nm) and meso crystals scale (2um~10um) were established, respectively. The mechanism of structural OH and molecular H2O translate through internal crystal structure, the mechanism of molecular H2O translate through crystal spaces and the supercritical water through crystal spaces and dislocations were explored and the relatively critical temperature and pressure to these specimens were obtained. The simulation results show that the diffusion, transport and dehydration energy of structural OH is two orders of magnitude than molecular H2O, and the diffusion, transport and dehydration energy of molecular H2O is one order of magnitude than supercritical water. Second, the diffusion, transport and dehydration process of structural OH, molecular H2O and supercritical water on the coseismic fault is studied and the relationship between micro dynamics friction coefficient, dehydration process and ultra temperature and pressure is presentation. The classical state and rate friction law is revised and extended micro state and rate friction law which consider the effect of fault interface rock dehydration and thermal diffusion is obtained, and these formulation will helpful understand the earthquake triggering mechanism and provide theoretical suggestion for earthquake early warning system. Key words Structural HO, molecular H2O and supercritical water, Diffusion transport and dehydration; Ultra high temperature and pressure; Developed

  15. Water Temperature, Voluntary Drinking and Fluid Balance in Dehydrated Taekwondo Athletes

    PubMed Central

    Khamnei, Saeed; Hosseinlou, Abdollah; Zamanlu, Masumeh

    2011-01-01

    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. Key points For athletes dehydrated in hot environments, maximum voluntary drinking and best hydration state occurs with 16°C water. Provision of fluid needs and thermal needs could be balanced using 16°C water. Drinking 16°C water (nearly the temperature of cool tap water) could be recommended for exercise in the heat. PMID:24149564

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

    PubMed Central

    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

  17. Dehydration of 1-octadecanol over H-BEA: A combined experimental and computational study

    SciTech Connect

    Song, Wenji; Liu, Yuanshuai; Barath, Eszter; Wang, Lucy; Zhao, Chen; Mei, Donghai; Lercher, Johannes A.

    2016-02-05

    Liquid phase dehydration of 1-octdecanol, which is intermediately formed during the hydrodeoxygenation of microalgae oil, has been explored in a combined experimental and computational study. The alkyl chain of C18 alcohol interacts with acid sites during diffusion inside the zeolite pores, resulting in an inefficient utilization of the Brønsted acid sites for samples with high acid site concentrations. The parallel intra- and inter- molecular dehydration pathways having different activation energies pass through alternative reaction intermediates. Formation of surface-bound alkoxide species is the rate-limiting step during intramolecular dehydration, whereas intermolecular dehydration proceeds via a bulky dimer intermediate. Octadecene is the primary dehydration product over H-BEA at 533 K. Despite of the main contribution of Brønsted acid sites towards both dehydration pathways, Lewis acid sites are also active in the formation of dioctadecyl ether. The intramolecular dehydration to octadecene and cleavage of the intermediately formed ether, however, require strong BAS. L. Wang, D. Mei and J. A. Lercher, acknowledge the partial support from the US Department of Energy, 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) and by the National Energy Research Scientific Computing Center (NERSC). 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.

  18. Dehydration-induced modulation of kappa-opioid inhibition of vasopressin neurone activity.

    PubMed

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

    2009-12-01

    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 kappa-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 kappa-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 -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 kappa-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.

  19. Water temperature, voluntary drinking and fluid balance in dehydrated taekwondo athletes.

    PubMed

    Khamnei, Saeed; Hosseinlou, Abdollah; Zamanlu, Masumeh

    2011-01-01

    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. Key pointsFor athletes dehydrated in hot environments, maximum voluntary drinking and best hydration state occurs with 16°C water.Provision of fluid needs and thermal needs could be balanced using 16°C water.Drinking 16°C water (nearly the temperature of cool tap water) could be recommended for exercise in the heat.

  20. Slow slip generated by dehydration reaction coupled with slip-induced dilatancy and thermal pressurization

    NASA Astrophysics Data System (ADS)

    Yamashita, Teruo; Schubnel, Alexandre

    2016-10-01

    Sustained slow slip, which is a distinctive feature of slow slip events (SSEs), is investigated theoretically, assuming a fault embedded within a fluid-saturated 1D thermo-poro-elastic medium. The object of study is specifically SSEs occurring at the down-dip edge of seismogenic zone in hot subduction zones, where mineral dehydrations (antigorite, lawsonite, chlorite, and glaucophane) are expected to occur near locations where deep slow slip events are observed. In the modeling, we introduce dehydration reactions, coupled with slip-induced dilatancy and thermal pressurization, and slip evolution is assumed to interact with fluid pressure change through Coulomb's frictional stress. Our calculations show that sustained slow slip events occur when the dehydration reaction is coupled with slip-induced dilatancy. Specifically, slow slip is favored by a low initial stress drop, an initial temperature of the medium close to that of the dehydration reaction equilibrium temperature, a low permeability, and overall negative volume change associated with the reaction (i.e., void space created by the reaction larger than the space occupied by the fluid released). Importantly, if we do not assume slip-induced dilatancy, slip is accelerated with time soon after the slip onset even if the dehydration reaction is assumed. This suggests that slow slip is sustained for a long time at hot subduction zones because dehydration reaction is coupled with slip-induced dilatancy. Such slip-induced dilatancy may occur at the down-dip edge of seismogenic zone at hot subduction zones because of repetitive occurrence of dehydration reaction there.

  1. Temperature dependent elasticity and damping in dehydrated sandstone

    NASA Astrophysics Data System (ADS)

    Darling, T. W.; Struble, W.

    2013-12-01

    Work reported previously at this conference, outlining our observation of anomalously large elastic softening and damping in dehydrated Berea sandstone at elevated temperatures, has been analysed to study shear and compressional effects separately. Modeling of the sample using COMSOL software was necessary to identify modes, as the vibration spectrum of the sample is poorly approximated by a uniform isotropic solid. The first torsional mode of our evacuated, dry, core softens at nearly twice the rate of Young's modulus modes (bending and compressional) and is also damped nearly twice as strongly as temperature increases. We consider two possible models for explaining this behavior, based on the assumption that the mechanical properties of the sandstone are dominated by the framework of quartz grains and polycrystalline cementation, neglecting initially the effects of clay and feldspar inclusions. The 20cm x 2.54cm diameter core is dry such that the pressure of water vapor in the experiment chamber is below 1e-6 Torr at 70C, suggesting that surface water beyond a small number of monolayers is negligible. Our models consider (1) enhanced sliding of grain boundaries in the cementation at elevated temperature and reduced internal water content, and (2) strain microcracking of the cementatioin at low water content due to anisotropic expansion in the quartz grains. In model (1) interfaces parallel to polyhedral grain surfaces were placed in the cement bonds and assigned frictional properties. Model (2) has not yet been implemented. The overall elasticity of a 3-D several-grain model network was determined by modeling quasistatic loading and measuring displacements. Initial results with a small number of grains/bonds suggests that only the first model provides softening and damping for all the modes, however the details of the effects of defect motioin at individual interfaces as the source for the frictional properties is still being evaluated. Nonlinear effects are

  2. Characterization of dehydration behavior of untreated and pulverized creatine monohydrate powders.

    PubMed

    Sakata, Yukoh; Shiraishi, Sumihiro; Otsuka, Makoto

    2004-06-01

    Creatine, which is well known as an important substance for muscular activity, is synthesized from amino acids such as glycine, arginine and ornithine in liver and kidney. It then accumulates in skeletal muscle as creatine phosphoric acid. The aim of this study was to understand the dehydration behavior of untreated and pulverized creatine monohydrate at various temperatures. The removal of crystal water was investigated by using differential scanning calorimetry (DSC), X-ray powder diffraction and scanning electron microscopy (SEM). The X-ray diffraction pattern of untreated and pulverized creatine monohydrate agreed with reported data for creatine monohydrate. However, the diffraction peaks of the (100), (200) and (300) planes of pulverized creatine monohydrate were much stronger than those of untreated creatine monohydrate. On the other hand, the diffraction peaks of the (012) and (013) planes of untreated creatine monohydrate were much stronger than those of pulverized creatine monohydrate. The dehydration of untreated and pulverized creatine monohydrate was investigated at various storage temperatures, and the results indicated that untreated and pulverized creatine monohydrate were transformed into the anhydrate at more than 30 degrees C. After dehydration, the particles of untreated and pulverized creatine anhydrate had many cracks. The dehydration kinetics of untreated and pulverized creatine monohydrate were analyzed by the Hancock-Sharp equation on the basis of the isothermal DSC data. The dehydrations of untreated and pulverized creatine monohydrate both followed a zero-order mechanism (Polany-Winger equation). However, the transition rate constant, calculated from the slope of the straight line, was about 2.2-7.7 times higher for pulverized creatine monohydrate than for untreated creatine monohydrate. The Arrhenius plots (natural logarithm of the dehydration rate constant versus the reciprocal of absolute temperature) of the isothermal DSC data for

  3. Colour, phenolic content and antioxidant capacity of some fruits dehydrated by a combination of different methods.

    PubMed

    Chong, Chien Hwa; Law, Chung Lim; Figiel, Adam; Wojdyło, Aneta; Oziembłowski, Maciej

    2013-12-15

    The objective of this study was to improve product quality of dehydrated fruits (apple, pear, papaya, mango) using combined drying techniques. This involved investigation of bioactivity, colour, and sensory assessment on colour of the dried products as well as the retention of the bio-active ingredients. The attributes of quality were compared in regard to the quality of dehydrated samples obtained from continuous heat pump (HP) drying technique. It was found that for apple, pear and mango the total colour change (ΔE) of samples dried using continuous heat pump (HP) or heat pump vacuum-microwave (HP/VM) methods was lower than of samples dried by other combined methods. However, for papaya, the lowest colour change exhibited by samples dried using hot air-cold air (HHC) method and the highest colour change was found for heat pump (HP) dehydrated samples. Sensory evaluation revealed that dehydrated pear with higher total colour change (ΔE) is more desirable because of its golden yellow appearance. In most cases the highest phenol content was found from fruits dried by HP/VM method. Judging from the quality findings on two important areas namely colour and bioactivity, it was found that combined drying method consisted of HP pre-drying followed by VM finish drying gave the best results for most dehydrated fruits studied in this work as the fruits contain first group of polyphenol compounds, which preferably requires low temperature followed by rapid drying strategy.

  4. Plant Organellar Proteomics in Response to Dehydration: Turning Protein Repertoire into Insights

    PubMed Central

    Gupta, Deepti B.; Rai, Yogita; Gayali, Saurabh; Chakraborty, Subhra; Chakraborty, Niranjan

    2016-01-01

    Stress adaptation or tolerance in plants is a complex phenomenon involving changes in physiological and metabolic processes. Plants must develop elaborate networks of defense mechanisms, and adapt to and survive for sustainable agriculture. Water-deficit or dehydration is the most critical environmental factor that plants are exposed to during their life cycle, which influences geographical distribution and productivity of many crop species. The cellular responses to dehydration are orchestrated by a series of multidirectional relays of biochemical events at organelle level. The new challenge is to dissect the underlying mechanisms controlling the perception of stress signals and their transmission to cellular machinery for activation of adaptive responses. The completeness of current descriptions of spatial distribution of proteins, the relevance of subcellular locations in diverse functional processes, and the changes of protein abundance in response to dehydration hold the key to understanding how plants cope with such stress conditions. During past decades, organellar proteomics has proved to be useful not only for deciphering reprograming of plant responses to dehydration, but also to dissect stress–responsive pathways. This review summarizes a range of organellar proteomics investigations under dehydration to gain a holistic view of plant responses to water-deficit conditions, which may facilitate future efforts to develop genetically engineered crops for better adaptation. PMID:27148291

  5. Anomalous dehydration of the TTL during January 2013: evidence from balloon, aircraft and satellite observations

    NASA Astrophysics Data System (ADS)

    Khaykin, Sergey; Pommereau, Jean-Pierre; Hauchecorne, Alain; Rivière, Emmanuel; Amarouche, Nadir; Ghysel, Melanie; Wienhold, Frank; Held, Gerard; Evan, Stephanie; Thornberry, Troy; Rollins, Andrew; Fahey, David; Vömel, Holger; Fujiwara, Masatomo; Rosenlof, Karen

    2015-04-01

    The goal of this study is to comprehensively document an anomalous dehydration of the Tropical Tropopause Layer (TTL) related to a major Sudden Stratospheric Warming (SSW) in January 2013. The analysis involves the data of balloon soundings of water vapour at various tropical locations using FLASH-B, Pico-SDLA and CFH hygrometers as well as NOAA Water instrument flown onboard high-altitude Global Hawk aircraft. Simultaneous water vapour and backscatter measurements by FLASH-B and COBALD sondes provide information on tropopause clouds formation process. Satellite observations of water vapour by Aura MLS are used to derive the deviation from climatological values. Trajectory modeling is applied for locating the dehydration source spots. Spatiotemporal evolution of dehydration at different scales is characterized after combining the consistent in situ and satellite water vapour observations. All data sets provide evidence of rapid and severe dehydration of the TTL throughout the tropical belt shortly after the onset of SSW. In situ measurements around the Cold Point Tropopause (CPT) show up to 2 ppmv of negative deviation from MLS 10-year climatology with extreme water mixing ratios below 1 ppmv in the Western Pacific region. The TTL dehydration case of 2013 is compared with previous similar occurrences and the role of extra-tropical dynamics in setting the global stratospheric water budget through thermal response in the TTL is pointed out

  6. Dehydration of Glucose to 5‐Hydroxymethylfurfural Using Nb‐doped Tungstite

    PubMed Central

    Yue, Chaochao; Li, Guanna; Pidko, Evgeny A.; Wiesfeld, Jan J.; Rigutto, Marcello

    2016-01-01

    Abstract 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 (WO3⋅H2O) 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 Brønsted 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 Brønsted acidity. In THF/water, the strong Lewis acidity and weak Brønsted 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. PMID:27493127

  7. ABI3 mediates dehydration stress recovery response in Arabidopsis thaliana by regulating expression of downstream genes.

    PubMed

    Bedi, Sonia; Sengupta, Sourabh; Ray, Anagh; Nag Chaudhuri, Ronita

    2016-09-01

    ABI3, originally discovered as a seed-specific transcription factor is now implicated to act beyond seed physiology, especially during abiotic stress. In non-seed plants, ABI3 is known to act in desiccation stress signaling. Here we show that ABI3 plays a role in dehydration stress response in Arabidopsis. ABI3 gene was upregulated during dehydration stress and its expression was maintained during subsequent stress recovery phases. Comparative gene expression studies in response to dehydration stress and stress recovery were done with genes which had potential ABI3 binding sites in their upstream regulatory regions. Such studies showed that several genes including known seed-specific factors like CRUCIFERIN1, CRUCIFERIN3 and LEA-group of genes like LEA76, LEA6, DEHYDRIN LEA and LEA-LIKE got upregulated in an ABI3-dependent manner, especially during the stress recovery phase. ABI3 got recruited to regions upstream to the transcription start site of these genes during dehydration stress response through direct or indirect DNA binding. Interestingly, ABI3 also binds to its own promoter region during such stress signaling. Nucleosomes covering potential ABI3 binding sites in the upstream sequences of the above-mentioned genes alter positions, and show increased H3 K9 acetylation during stress-induced transcription. ABI3 thus mediates dehydration stress signaling in Arabidopsis through regulation of a group of genes that play a role primarily during stress recovery phase.

  8. Impact induced dehydration of serpentine and the evolution of planetary atmospheres

    SciTech Connect

    Lange, M.A.; Ahrens, T.J.

    1982-11-15

    Shock recovery experiments in the 25 to 45 GPa range on antigorite serpentine determine the amount of shock-induced loss of structural water as a function of shock pressure. Infrared absorption spectra of shock recovered samples demonstrate systematic changes in the amount of structural water and molecular, surface adsorbed water. These yield qualitative estimates of shock-induced water loss and demonstrate that a portion of the shock release structural water is readsorbed on interfacial grain surfaces. Determination of the post-shock water content of the shocked samples relates shock-induced water loss and shock pressure. Based on the present results and theoretical predictions, we conclude that shock pressures of from 20 to approx.60 GPa induce incipient to complete water loss, respectively. This result agrees closely with theoretical estimates for total dehydration. The dehydration interval and the activation energies for dehydration in shocked samples decrease systematically with increasing shock pressure as experienced by the sample. We believe the present experiments are applicable to describing dehydration processes of serpentine-like minerals in the accretional environment of the terrestrial planets. We conclude that complete loss of structural water in serpentine could have occurred from accretional impacts of approx.3 km/sec when earth and Venus have grown to about 50% of their final size. Accreting planetesimals, impacting Mars, never reached velocities sufficient for complete dehydration of serpentine. Our results support a model in which an impact generated atmosphere/hydrosphere forms while the earth is accreting.

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

    PubMed Central

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

    2016-01-01

    ABSTRACT 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. PMID:28349082

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Localized slip controlled by dehydration embrittlement of partly serpentinized dunites, Leka Ophiolite Complex, Norway

    NASA Astrophysics Data System (ADS)

    Dunkel, Kristina G.; Austrheim, Håkon; Renard, François; Cordonnier, Benoit; Jamtveit, Bjørn

    2017-04-01

    Dehydration of partly or completely serpentinized ultramafic rocks can increase the pore fluid pressure and induce brittle failure, a process referred to as dehydration embrittlement. However the extents of strain localization and unstable frictional sliding during deserpentinization are still under debate. In the layered ultramafic sections of the Leka Ophiolite Complex in the Central Norwegian Caledonides, prograde metamorphism of serpentinite veins led to local fluid production and to the growth of Mg-rich and coarse-grained olivine with abundant magnetite inclusions and δ18O values 1.0- 1.5 ‰ below the host rock. Embrittlement associated with the dehydration caused faulting along highly localized (<10 μm-wide) slip planes near the centers of the original serpentinite veins and pulverization of wall rock olivine. These features along with an earthquake-like size distribution of fault offsets suggest unstable frictional sliding rather than slower creep. Structural heterogeneities in the form of serpentinite veins clearly have first-order controls on strain localization and frictional sliding during dehydration. As most of the oceanic lithosphere is incompletely serpentinized, heterogeneities represented by a non-uniform distribution of serpentinite are common and may increase the likelihood that dehydration embrittlement triggers earthquakes.

  12. Differential dehydration effects on globular proteins and intrinsically disordered proteins during film formation.

    PubMed

    Yoneda, Juliana Sakamoto; Miles, Andew J; Araujo, Ana Paula Ulian; Wallace, B A

    2017-04-01

    Globular proteins composed of different secondary structures and fold types were examined by synchrotron radiation circular dichroism spectroscopy to determine the effects of dehydration on their secondary structures. They exhibited only minor changes upon removal of bulk water during film formation, contrary to previously reported studies of proteins dehydrated by lyophilization (where substantial loss of helical structure and gain in sheet structure was detected). This near lack of conformational change observed for globular proteins contrasts with intrinsically disordered proteins (IDPs) dried in the same manner: the IDPs, which have almost completely unordered structures in solution, exhibited increased amounts of regular (mostly helical) secondary structures when dehydrated, suggesting formation of new intra-protein hydrogen bonds replacing solvent-protein hydrogen bonds, in a process which may mimic interactions that occur when IDPs bind to partner molecules. This study has thus shown that the secondary structures of globular and intrinsically disordered proteins behave very differently upon dehydration, and that films are a potentially useful format for examining dehydrated soluble proteins and assessing IDPs structures.

  13. Differential dehydration effects on globular proteins and intrinsically disordered proteins during film formation

    PubMed Central

    Yoneda, Juliana Sakamoto; Miles, Andew J.; Araujo, Ana Paula Ulian

    2017-01-01

    Abstract Globular proteins composed of different secondary structures and fold types were examined by synchrotron radiation circular dichroism spectroscopy to determine the effects of dehydration on their secondary structures. They exhibited only minor changes upon removal of bulk water during film formation, contrary to previously reported studies of proteins dehydrated by lyophilization (where substantial loss of helical structure and gain in sheet structure was detected). This near lack of conformational change observed for globular proteins contrasts with intrinsically disordered proteins (IDPs) dried in the same manner: the IDPs, which have almost completely unordered structures in solution, exhibited increased amounts of regular (mostly helical) secondary structures when dehydrated, suggesting formation of new intra‐protein hydrogen bonds replacing solvent‐protein hydrogen bonds, in a process which may mimic interactions that occur when IDPs bind to partner molecules. This study has thus shown that the secondary structures of globular and intrinsically disordered proteins behave very differently upon dehydration, and that films are a potentially useful format for examining dehydrated soluble proteins and assessing IDPs structures. PMID:28097742

  14. Ethanol dehydration in HZSM-5 studied by density functional theory: evidence for a concerted process.

    PubMed

    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.

  15. Photosynthetic responses of thalli and isolated protoplasts of Bryopsis hypnoides (Bryopsidales, Chlorophyta) during dehydration

    NASA Astrophysics Data System (ADS)

    Lü, Fang; Wang, Guangce; Jin, Haochen

    2011-03-01

    Bryopsis hypnoides Lamouroux is a unique intertidal siphonous green alga whose extruded protoplasm can aggregate spontaneously in seawater to form numerous new cells that can develop into mature algal thalli. In this study, the photosynthetic responses during dehydration of both the thalli and protoplasts isolated from B. hypnoides were measured using a Dual-PAM (pulse amplitude modulation)-100 fluorometer. The results show that the photosynthetic rates of B. hypnoides thalli were maintained for an initial period, beyond which continued desiccation resulted in reduced rates of PSI and PSII. However, the photosynthetic performances of the isolated protoplasts dehydrated in air (CO2 concentration 600-700 mg/L) showed a slight increase of Y(II) at 20% water loss, but the rates decreased thereafter with declining water content. When protoplasts were dehydrated in CO2 deficient conditions (CO2 concentration 40-80 mg/L), the values of Y(II) declined steadily with increased dehydration without an initial rise. These results indicated that the thalli and isolated protoplasts of this alga can utilize CO2 in ambient air effectively, and the photosynthetic performances of the isolated protoplasts were significantly different from that of the thalli during dehydration. Thus the protoplasts may be an excellent system for the study of stress tolerance.

  16. Differential proteomics of dehydration and rehydration in bryophytes: evidence towards a common desiccation tolerance mechanism.

    PubMed

    Cruz DE Carvalho, Ricardo; Bernardes DA Silva, Anabela; Soares, Renata; Almeida, André M; Coelho, Ana Varela; Marques DA Silva, Jorge; Branquinho, Cristina

    2014-07-01

    All bryophytes evolved desiccation tolerance (DT) mechanisms during the invasion of terrestrial habitats by early land plants. Are these DT mechanisms still present in bryophytes that colonize aquatic habitats? The aquatic bryophyte Fontinalis antipyretica Hedw. was subjected to two drying regimes and alterations in protein profiles and sucrose accumulation during dehydration and rehydration were investigated. Results show that during fast dehydration, there is very little variation in protein profiles, and upon rehydration proteins are leaked. On the other hand, slow dehydration induces changes in both dehydration and rehydration protein profiles, being similar to the protein profiles displayed by the terrestrial bryophytes Physcomitrella patens (Hedw.) Bruch and Schimp. and, to what is comparable with Syntrichia ruralis (Hedw.) F. Weber and D. Mohr. During dehydration there was a reduction in proteins associated with photosynthesis and the cytoskeleton, and an associated accumulation of proteins involved in sugar metabolism and plant defence mechanisms. Upon rehydration, protein accumulation patterns return to control values for both photosynthesis and cytoskeleton whereas proteins associated with sugar metabolism and defence proteins remain high. The current results suggest that bryophytes from different ecological adaptations may share common DT mechanisms.

  17. The dehydration kinetics of gypsum at high pressure and high temperature

    NASA Astrophysics Data System (ADS)

    Liu, Chuanjiang; Zheng, Haifei; Wang, Duojun

    2015-07-01

    An in situ dehydration kinetics study of gypsum under water-saturated condition was performed in the temperature and pressure ranges of 383-423 K and 343-1085 MPa by using a hydrothermal diamond anvil cell and Raman spectroscopy. Kinetic analysis shows that the dehydration rate k increases with pressure, suggesting a negative pressure dependence on dehydration rate. The elevation of temperature can contribute to the dehydration. The n values increase with pressure, indicating that the nucleation process becomes slower relative to the growth process. According to the n values of ∼1.0, the dehydration of gypsum is dominated by an instantaneous nucleation and diffusion-controlled growth mechanism. The obtained average activation volume ▵V is equal to 5.69 cm3/mol and the calculated activation energy Ea and the pre-exponential factor A are 66.9 kJ/mol and 4.66 × 105 s-1. The activation energy may be dependent upon grain size, shape, temperature and pressure, and surrounding water.

  18. Simulation of mass transfer during osmotic dehydration of apple: a power law approximation method

    NASA Astrophysics Data System (ADS)

    Abbasi Souraki, B.; Tondro, H.; Ghavami, M.

    2014-10-01

    In this study, unsteady one-dimensional mass transfer during osmotic dehydration of apple was modeled using an approximate mathematical model. The mathematical model has been developed based on a power law profile approximation for moisture and solute concentrations in the spatial direction. The proposed model was validated by the experimental water loss and solute gain data, obtained from osmotic dehydration of infinite slab and cylindrical shape samples of apple in sucrose solutions (30, 40 and 50 % w/w), at different temperatures (30, 40 and 50 °C). The proposed model's predictions were also compared with the exact analytical and also a parabolic approximation model's predictions. The values of mean relative errors respect to the experimental data were estimated between 4.5 and 8.1 %, 6.5 and 10.2 %, and 15.0 and 19.1 %, for exact analytical, power law and parabolic approximation methods, respectively. Although the parabolic approximation leads to simpler relations, the power law approximation method results in higher accuracy of average concentrations over the whole domain of dehydration time. Considering both simplicity and precision of the mathematical models, the power law model for short dehydration times and the simplified exact analytical model for long dehydration times could be used for explanation of the variations of the average water loss and solute gain in the whole domain of dimensionless times.

  19. Quantitative analysis of dehydration in porcine skin for assessing mechanism of optical clearing

    NASA Astrophysics Data System (ADS)

    Yu, Tingting; Wen, Xiang; Tuchin, Valery V.; Luo, Qingming; Zhu, Dan

    2011-09-01

    Dehydration induced by optical clearing agents (OCAs) can improve tissue optical transmittance; however, current studies merely gave some qualitative descriptions. We develop a model to quantitatively evaluate water content with partial least-squares method based on the measurements of near-infrared reflectance spectroscopy and weight of porcine skin. Furthermore, a commercial spectrometer with an integrating sphere is used to measure the transmittance and reflectance of skin after treatment with different OCAs, and then the water content and optical properties of sample are calculated, respectively. The results show that both the reduced scattering coefficient and dehydration of skin decrease with prolongation of action of OCAs, but the relative change in former is larger than that in latter after a 60-min treatment. The absorption coefficient at 1450 nm decreases completely coincident with dehydration of skin. Further analysis illustrates that the correlation coefficient between the relative changes in the reduced scattering coefficient and dehydration is ~1 during the 60-min treatment of agents, but there is an extremely significant difference between the two parameters for some OCAs with more hydroxyl groups, especially, glycerol or D-sorbitol, which means that the dehydration is a main mechanism of skin optical clearing, but not the only mechanism.

  20. (100) facets of γ-Al2O3: the active surfaces for alcohol dehydration reactions

    SciTech Connect

    Kwak, Ja Hun; Mei, Donghai; Peden, Charles HF; Rousseau, Roger J.; Szanyi, Janos

    2011-05-01

    Temperature programmed desorption (TPD) of ethanol, and methanol dehydration reaction were studied on γ-Al2O3 in order to identify the catalytic active sites for alcohol dehydration reactions. Two high temperature (> 473 K) desorption features were observed following ethanol adsorption. Samples calcined at T≤473 K displayed a desorption feature in the 523-533 K temperature range, while those calcined at T ≥ 673 K showed a single desorption feature at 498 K. The switch from the high to low temperature ethanol desorption correlated well with the dehydroxylation of the (100) facets of γ-Al2O3 that was predicted at 550 K DFT calculations. Theoretical DFT simulations of the mechanism of dehydration. on clean and hydroxylated γ-Al2O3(100) surfaces, find that a concerted elimination of ethylene from an ethanol molecule chemisorbed at an Al3+ pentacoordinated site is the rate limiting step for catalytic cycle on both surfaces. Furthermore, titration of the pentacoordinate Al3+ sites on the (100) facets of γ-Al2O3 by BaO completely turned off the methanol dehydration reaction activity. These results unambiguously demonstrate that only the (100) facets on γ-Al2O3 are the catalytic active surfaces for alcohol dehydration.

  1. Influence of dehydration process in Castellano chickpea: changes in bioactive carbohydrates and functional properties.

    PubMed

    Aguilera, Yolanda; Benítez, Vanesa; Mollá, Esperanza; Esteban, Rosa M; Martín-Cabrejas, María A

    2011-11-01

    Changes in bioactive carbohydrates, functional, and microstructural characteristics that occurred in chickpea under soaking, cooking, and industrial dehydration processing were evaluated. Raw chickpea exhibited important levels of raffinose family of oligosaccharides (RFOs), resistant starch (RS) and total dietary fibre (TDF), being insoluble dietary fibre (IDF) the main fraction (94%). The dehydration process increased RFOs (43%), RS (47%) and soluble dietary fiber (SDF) (59%) levels significantly. In addition, a noticeable increase in both fibre fractions was observed, being higher in soluble fibre in (SDF) (59%). The minimum nitrogen solubility of raw flours was at pH 4, and a high degree of protein insolubilization (80%) was observed in dehydrated flours. The raw and processed flours exhibited low oil-holding capacities (1.10 mg/ml), and did not show any change by thermal processing, whereas water-holding capacities rose to 5.50 mg/ml of sample. Cooking and industrial dehydration process reduced emulsifying activity and foaming capacity of chickpea flour. The microstructural observations were consistent with the chemical results. Thus, the significant occurrence of these bioactive carbohydrate compounds along with the interesting functional properties of the dehydrated flours could be considered useful as functional ingredients for food formulation.

  2. Pyropia yezoensis can utilize CO2 in the air during moderate dehydration

    NASA Astrophysics Data System (ADS)

    Zhou, Wei; He, Linwen; Yang, Fang; Lin, Apeng; Zhang, Baoyu; Niu, Jianfeng; Wang, Guangce

    2014-03-01

    Pyropia yezoensis, an intertidal seaweed, experiences regular dehydration and rehydration with the tides. In this study, the responses of P. yezoensis to dehydration and rehydration under high and low CO2 concentrations ((600-700)×10-6 and (40-80)×10-6, named Group I and Group II respectively) were investigated. The thalli of Group I had a significantly higher effective photosystem II quantum yield than the thalli of Group II at 71% absolute water content (AWC). There was little difference between thalli morphology, total Rubisco activity and total protein content at 100% and 71% AWC, which might be the basis for the normal performance of photosynthesis during moderate dehydration. A higher effective photosystem I quantum yield was observed in the thalli subjected to a low CO2 concentration during moderate dehydration, which might be caused by the enhancement of cyclic electron flow. These results suggested that P. yezoensis can directly utilize CO2 in ambient air during moderate dehydration.

  3. Small-angle Scattering Study of Mesoscopic Structures in Charged Gel and Their Evolution in Dehydration

    SciTech Connect

    Sugiyama, M.; Annaka, M.; Hara, K.; Vigild, M. E.; Wignall, George D

    2003-01-01

    Mesoscopic structures, with length scales {approx}10{sup 2} {angstrom}, were investigated by small-angle X-ray and neutron scattering (SAXS and SANS) in several N-isopropylacrylamide-sodium acrylate (NIPA-SA) copolymeric hydrogels with varying [NIPA]/[SA] ratios and water contents. The SAXS experiments reveal that, depending upon the [NIPA]/[SA] ratio, the dehydrated NIPA-SA gel shows two mesoscopic structures: one consists of randomly distributed SA-rich islands in NIPA matrix, while the other is a microphase-separated structure, composed of NIPA-rich and SA-rich domains. In addition, the SANS experiments reveal the mesoscopic structural features during the dehydration process. As the concentration of the network polymers increases, NIPA-rich and water-rich domains segregate in the gel. Then, an electrostatic interaction between the segregated domains induces a microphase-separated structure in the limit of the dehydrated NIPA-SA gel.

  4. Autophagy in Antarctica: combating dehydration stress in the world's southernmost insect.

    PubMed

    Teets, Nicholas M; Denlinger, David L

    2013-04-01

    The midge Belgica antarctica is the only insect endemic to Antarctica and has the southernmost range of any insect. In its natural environment, B. antarctica frequently faces desiccating conditions, as environmental water is frozen for up to 9 months annually. The molecular mechanisms by which B. antarctica tolerates extreme dehydration are poorly understood, but recent work from our laboratory reports genome-wide expression changes in response to extreme dehydration (~40% water loss), the first genome-scale transcriptome reported for an Antarctic animal. Among transcripts differentially regulated during dehydration, there is coordinated upregulation of numerous genes involved in autophagy, including genes responsible for autophagosome synthesis and autophagy-associated transcription factors. Also, several genes and pathways that interact with and regulate autophagy, e.g., sestrins and proteasomal genes, are concurrently upregulated. This suggests that autophagy and related processes are key elements regulating stress tolerance in this extreme environment.

  5. Synthesis of butenes through 2-butanol dehydration over mesoporous materials produced from ferrierite

    SciTech Connect

    Jeong, Soyeon; Kim, Hyeonjoo; Bae, Jung A.; Kim, Do Heui; Peden, Charles HF; Park, Young-Kwon; Jeon, Jong Ki

    2012-05-20

    Mesoporous materials synthesized from commercial ferrierite (MMZ-FER) were applied to butanol dehydration. The MMZ-FER was produced by disassembling ferrierite into unit structures in the presence of an alkali solution, adding a surfactant as a templating material, followed by hydrothermal treatment. The effect of the alkali/(Si+Al) ratio in the disassembling step on the characteristics of the catalyst and butanol dehydration performance were investigated. The MMZ-FER materials, synthesized in a condition in which the NaOH/(Si + Al) mole ratio in the disassembling step was 0.67 and 1.0, demonstrated similar textural properties to those of MCM-41. Many weak acid sites developed on the MMZ-FER(0.67) and MMZ-FER(1.0) samples, which is attributed to the creation of ferrierite-induced acid sites. The MMZ-FER materials showed excellent catalytic activity, selectivity, and stability during the dehydration of 2-butanol.

  6. Improvement of Freezing Quality of Food by Pre-dehydration with Microwave-Vacuum Drying

    NASA Astrophysics Data System (ADS)

    Hamidi, Nurkholis; Tsuruta, Takaharu

    Partial dehydration by microwave vacuum drying has been applied to tuna, oyster and mackerel prior to freezing in order to reduce quality damages due to freezing and thawing. Samples were dehydrated at pressure of 4kPa and temperature lower than 25°C. Two cooling conditions were tested in the experiment by using the freezing chamber of temperatures -20°C and -80°C. The experimental results showed that decreasing the water content in tuna could lower the freezing point temperature and made the freezing time shorter. It was also found that removing some water was effective to reduce the size of ice crystal and the drip loss in mackerel. After thawing, the pre-dehydrated mackerel showed better microstructure than that frozen without pre-treatment. Furthermore, the sensory tests have been done by a group of panelist for the evaluation on aroma, flavor, and general acceptability of mackerels.

  7. [Quality evaluation of a dehydrated product based on potato (Solanum tuberosum), lupin (Lupinus mutabilis) and eggs].

    PubMed

    Glorio Paulet, P; Reynoso Zárate, Z

    1993-03-01

    After a mathematical evaluation of 20 mixtures containing different proportions of potato (P), lupin (L) and whole egg (E) on dry basis and kept the latter component in a constant amount of 6 per cent, a mixture of 60:34:6 (P:L:E) was chosen for a further experimental work at a lab level because of his better nutritional value for the pre-school children feeding. When an eighteen percent suspension of the mixture mentioned above was dehydrated in a drum drier an adecuate yield of flakes was obtained with an appropriate water absorption. The sensory evaluation test of the dehydrated product as a sauce indicated a higher acceptance than purées. On the other hand, during a 90 days period storage test of the product as flakes, it did not show microbiological problems, although after 45 days rancidity appeared in the dehydrated product.

  8. Apex cryopreservation of several strawberry genotypes by two encapsulation-dehydration methods.

    PubMed

    Clavero-Ramírez, I; Gálvez-Farfán, J; López-Aranda, J M; González-Benito, M E

    2005-01-01

    This paper presents results from a study to develop cryopreservation procedures for apices of several strawberry genotypes. Five Fragaria x ananassa Duch. cultivars and two wild species (F. chiloensis and F. virginiana) have been screened using the encapsulation-dehydration method and/or a protocol which compromises vitrification and encapsulation-dehydration. Apices were encapsulated in an alginate gel, precultured on media containing high levels of sucrose (0.8 M, conventional protocol), or a combination of 0.4 M sucrose and 2 M glycerol. Recovery rates varied among genotypes (23-63%). The latter method reduced considerably the time needed for the cryogenic procedure by eliminating the pre-treatment with 0.8 M sucrose for 19 h prior to dehydration, as required by the conventional procedure.

  9. Cryopreservation by encapsulation-dehydration of plumules of coconut (Cocos nucifera L.).

    PubMed

    N'Nan, Oulo; Hocher, Valérie; Verdeil, Jean-Luc; Konan, Jean-Louis; Ballo, Koffi; Mondeil, Fanja; Malaurie, Bernard

    2008-01-01

    This study describes the use of an encapsulation-dehydration cryopreservation technique on coconut plumules (apical dome with three or four leaf primordia) excised from embryos. In order to establish a reliable cryopreservation process for plumules, several different key factors were tested: pretreatment duration, sugar concentration, dehydration period and freezing. In parallel, histological studies were performed to describe the structural changes of tissues and plumule cells subjected to dehydration and freezing. A good survival level of around 60% was obtained. However, after 8 months culture regrowth, this level decreased to a maximum of 20 % which was achieved using sucrose treatment. In this paper we report for the first time the regeneration of leafy shoots from coconut plumules after cryopreservation.

  10. Instability of myelin tubes under dehydration: deswelling of layered cylindrical structures.

    PubMed

    Chen, C M; Schmidt, C F; Olmsted, P D; MacKintosh, F C

    2001-11-01

    We report experimental observations of an undulational instability of myelin figures. Motivated by this, we examine theoretically the deformation and possible instability of concentric, cylindrical, multilamellar membrane structures. Under conditions of osmotic stress (swelling or dehydration), we find a stable, deformed state in which the layer deformation is given by deltaR infinity r(square root[B(A)/(hB)]), where B(A) is the area compression modulus, B is the interlayer compression modulus, and h is the repeat distance of layers. Also, above a finite threshold of dehydration (or osmotic stress), we find that the system becomes unstable to undulations, first with a characteristic wavelength of order square root[xi(d)0], where xi is the standard smectic penetration depth and d0 is the thickness of dehydrated region.

  11. Dehydration kinetics and thermochemistry of selected hydrous phases, and simulated gas release pattern in carbonaceous chondrites

    NASA Technical Reports Server (NTRS)

    Bose, Kunal; Ganguly, J.

    1992-01-01

    As part of our continued program of study on the volatile bearing phases and volatile resource potential of carbonaceous chondrite, results of our experimental studies on the dehydration kinetics of talc as a function of temperature and grain size (50 to 0.5 microns), equilibrium dehydration boundary of talc to 40 kbars, calorimetric study of enthalpy of formation of both natural and synthetic talc as a function of grain size, and preliminary results on the dehydration kinetics of epsomite are reported. In addition, theoretical calculations on the gas release pattern of Murchison meteorite, which is a C2(CM) carbonaceous chondrite, were performed. The kinetic study of talc leads to a dehydration rate constant for 40-50 microns size fraction of k = (3.23 x 10(exp 4))exp(-Q/RT)/min with the activation energy Q = 376 (plus or minus 20) kJ/mole. The dehydration rate was found to increase somewhat with decreasing grain size. The enthalpy of formation of talc from elements was measured to be -5896(10) kJ/mol. There was no measurable effect of grain size on the enthalpy beyond the limits of precision of the calorimetric studies. Also the calorimetric enthalpy of both synthetic and natural talc was found to be essentially the same, within the precision of measurements, although the natural talc had a slightly larger field of stability in our phase equilibrium studies. The high pressure experimental data the dehydration equilibrium of talc (talc = enstatite + coesite + H2O) is in strong disagreement with that calculated from the available thermochemical data, which were constrained to fit the low pressure experimental results. The calculated gas release pattern of Murchison meteorite were in reasonable agreement with that determined by stepwise heating in a gas chromatograph.

  12. Cryoprotective dehydration and the resistance to inoculative freezing in the Antarctic midge, Belgica antarctica.

    PubMed

    Elnitsky, Michael A; Hayward, Scott A L; Rinehart, Joseph P; Denlinger, David L; Lee, Richard E

    2008-02-01

    During winter, larvae of the Antarctic midge, Belgica antarctica (Diptera, Chironomidae), must endure 7-8 months of continuous subzero temperatures, encasement in a matrix of soil and ice, and severely desiccating conditions. This environment, along with the fact that larvae possess a high rate of water loss and are extremely tolerant of desiccation, may promote the use of cryoprotective dehydration as a strategy for winter survival. This study investigates the capacity of larvae to resist inoculative freezing and undergo cryoprotective dehydration at subzero temperatures. Slow cooling to -3 degrees C in an environment at equilibrium with the vapor pressure of ice reduced larval water content by approximately 40% and depressed the body fluid melting point more than threefold to -2.6 degrees C. This melting point depression was the result of the concentration of existing solutes (i.e. loss of body water) and the de novo synthesis of osmolytes. By day 14 of the subzero exposure, larval survival was still >95%, suggesting larvae have the capacity to undergo cryoprotective dehydration. However, under natural conditions the use of cryoprotective dehydration may be constrained by inoculative freezing as result of the insect's intimate contact with environmental ice. During slow cooling within a substrate of frozen soil, the ability of larvae to resist inoculative freezing and undergo cryoprotective dehydration was dependent upon the moisture content of the soil. As detected by a reduction of larval water content, the percentage of larvae that resisted inoculative freezing increased with decreasing soil moisture. These results suggest that larvae of the Antarctic midge have the capacity to resist inoculative freezing at relatively low soil moisture contents and likely undergo cryoprotective dehydration when exposed to subzero temperatures during the polar winter.

  13. Identification of Circular RNAs and Their Targets in Leaves of Triticum aestivum L. under Dehydration Stress

    PubMed Central

    Wang, Yuexia; Yang, Ming; Wei, Shimei; Qin, Fujun; Zhao, Huijie; Suo, Biao

    2017-01-01

    Circular RNAs (circRNAs) are a type of newly identified non-coding RNAs through high-throughput deep sequencing, which play important roles in miRNA function and transcriptional controlling in human, animals, and plants. To date, there is no report in wheat seedlings regarding the circRNAs identification and roles in the dehydration stress response. In present study, the total RNA was extracted from leaves of wheat seedlings under dehydration-stressed and well-watered conditions, respectively. Then, the circRNAs enriched library based deep sequencing was performed and the circRNAs were identified using bioinformatics tools. Around 88 circRNAs candidates were isolated in wheat seedlings leaves while 62 were differentially expressed in dehydration-stressed seedlings compared to well-watered control. Among the dehydration responsive circRNAs, six were found to act as 26 corresponding miRNAs sponges in wheat. Sixteen circRNAs including the 6 miRNAs sponges and other 10 randomly selected ones were further validated to be circular by real-time PCR assay, and 14 displayed consistent regulation patterns with the transcriptome sequencing results. After Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the targeted mRNAs functions, the circRNAs were predicted to be involved in dehydration responsive process, such as photosynthesis, porphyrin, and chlorophyll metabolism, oxidative phosphorylation, amino acid biosynthesis, and metabolism, as well as plant hormone signal transduction, involving auxin, brassinosteroid, and salicylic acid. Herein, we revealed a possible connection between the regulations of circRNAs with the expressions of functional genes in wheat leaves associated with dehydration resistance. PMID:28105043

  14. Buffering and inhibition of glycol in gas dehydration applications: An alternative to amines

    SciTech Connect

    Stefl, B.A.; Bosen, S.F.

    1995-12-01

    Corrosion in gas dehydration systems can be attributed to many factors, including chloride intrusion, acid gas absorption, and glycol degradation. Inhibition systems for glycol dehydration systems must incorporate both corrosion inhibition and buffering, utilizing stable, non-scaling, non-depleting additives. Traditional amine treatments are unstable in CO{sub 2} containing gas streams; traditional inorganic salt glycol inhibitors are unstable and cause scaling in the presence of intruded mineral salts. An alternative inhibitor technology was tested in three field test programs, under various dehydration conditions. Traditional nitrite, molybdate, and amine inhibitors were tested in combination with the alternative technology; uninhibited and amine inhibited control units were included in the study. Corrosion rates and dehydration fluid chemistries were monitored. The field tests demonstrated the effectiveness of the non-amine-based alternative technology in reducing corrosion rates and maintaining the alkalinity of the glycol dehydration fluid. Corrosion rates at the reboiler in systems treated with the alternative technology averaged ten times less than the average rate in the control units, and had a substantially lower incidence of localized corrosion. The pH of the treated glycol stayed alkaline throughout the testing, varying within 0.85 pH units; whereas corresponding control units showed wide swings in pH, ranging from an acidic 4.1 to an alkaline 10.3. No operational difficulties, including foaming, inadequate drying, or excess glycol loss, were experienced in the treated dehydration units. Testing of the alternative technology in combination with more traditional technologies revealed no significant benefits over the alternative technology alone; however, the alternate technology showed significant improvements in both corrosion control and stability over traditional amine inhibition.

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

    PubMed

    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 < 0.001) from 1.028 ± 0.001 to 1.020 ± 0.001 during the approximately 22-hour rehydration period. Results demonstrated that 39% of the MMA fighters presented with a Usg of >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.

  16. Pharmacokinetics of intravenous chlorzoxazone in rats with dehydration and rehydration: effects of food intakes.

    PubMed

    Kim, Yu C; Kim, Yoon G; Kim, Eun J; Cho, Min K; Kim, Sang G; Lee, Myung G

    2003-03-01

    The following results were obtained recently from our laboratories; in rats with 72-h water deprivation (rats with dehydration), the hepatic cytochrome P450 2E1 (CYP2E1) was three-fold induced with an increase in the mRNA. Rehydration of 48-h water-deprived rats for the next 24 h with free access of food (rats with rehydration) restored CYP2E1 level to that of control. However, rehydration of 48-h water-deprived rats for the next 24 h with limited food supply (20% of control) failed to restore the CYP2E1 level to that of control. Hence, the CYP2E1 changes in rats with dehydration and rehydration resulted from differences in food intakes but not from dehydration or rehydration per'se. Chlorzoxazone (CZX) is metabolized to 6-hydroxychlorzoxazone (OH-CZX) mainly by CYP2E1 in rats. Therefore, the pharmacokinetics of CZX and OH-CZX were compared after intravenous administration of CZX, 25 mg/kg, to control rats and rats with dehydration and rehydration with free access of food. In rats with dehydration, the amount of 24-h urinary excretion of free OH-CZX plus its glucuronide conjugates (Ae (OH-CZX, 0-24 h,) expressed in terms of intravenous dose of CZX) was significantly greater (45.6 compared with 35.6%) and area under the plasma concentration-time curve from time zero to time infinity (AUC) of CZX was significantly smaller (2190 compared with 3200 micro g min/ml) than those in control rats. The above data indicated that the formation of OH-CZX increased significantly in rats with dehydration due to 3-fold induction of CYP2E1. In rats with rehydration with free access of food, the Ae (OH-CZX, 0-24 h) (39.0 compared with 35.6%) and AUC of CZX (2870 compared with 3200 micro g min/ml) were restored (comparable) to control levels since the expression of CYP2E1 in rats with dehydration returned to control level by rehydration. The above data indicate that CZX could be used as a chemical probe to assess the activity of CYP2E1 in rats with dehydration and rehydration.

  17. Glycerol Dehydration to Acrolein Catalyzed by ZSM‐5 Zeolite in Supercritical Carbon Dioxide Medium

    PubMed Central

    Zou, Bin; Ren, Shoujie

    2016-01-01

    Abstract Supercritical carbon dioxide (SC‐CO2) has been used for the first time as a reaction medium for the dehydration of glycerol to acrolein catalyzed by a solid acid. Unprecedented catalyst stability over 528 hours of time‐on‐stream was achieved and the rate of coke deposition on the zeolite catalyst was the lowest among extensive previous studies, showing potential for industrial application. Coking pathways in SC‐CO2 were also elucidated for future development. The results have potential implications for other dehydration reactions catalyzed by solid acids. PMID:27796088

  18. Overpressure Caused by the Smectite Dehydration Influences on the triggering of fault slip

    NASA Astrophysics Data System (ADS)

    Lin, Wen-Sheng; Liu, Chen-Wuing; Chang, Han-Yuan

    2015-04-01

    Overpressure, which is pore fluid pressure higher than hydrostatic pressure, is observed in numerous mechanical processes along major faults. Many investigations currently show that the pore fluid pressure has been observed to influence the thrust fault strength and slip behavior and updip limit of the seismogenic zone. Clay dehydration is one key control on overpressure generation under undrained condition in thermal pressurization processes. Increasing pressure and temperature with depth depending on the local geological setting and conditions can cause clay dehydration which has been proposed as an explanation for the generation of overpressure. However, study about the effect of excess pore pressure caused by clay dehydration on the triggering of earthquake is seldom addressed in Taiwan. In fault zones like the Chelungpu Fault, clay minerals are abundant in the fault gouge. Therefore, to quantify the effect of overpressure caused by clay dehydration on the triggering of earthquake under undrained condition, we adopt the chemical thermodynamic model and chemical kinetic model to calculate the amount of water expelled from clay dehydration; derive the three-dimensional governing equation of groundwater flow with clay dehydration varied with pressure and temperature; follow the Coulomb-Mohr frictional failure model of earthquake occurrence to evaluate the influence of the pore pressure on the change of effective Coulomb stress. Finally, development of numerical model to simulate the effect of excess pore pressure caused by clay dehydration on the coulomb failure stress coupled thermal-hydraulic-mechanical-chemical has been performed. Moreover, field application with numerical model to quantify analysis of the effect of overpressure caused by clay dehydration on the triggering of earthquake has been progressed. Coulomb stress increases of ≥0.01 MPa have been shown to be associated with seismicity rate increase and in many cases triggering earthquakes. The results

  19. Dehydration and Symptoms of Delayed-Onset Muscle Soreness in Normothermic Men

    PubMed Central

    Cleary, Michelle A; Sitler, Michael R; Kendrick, Zebulon V

    2006-01-01

    Context: A dehydrated individual who performs eccentric exercise may exacerbate skeletal muscle damage, leading to structural, contractile, and enzymatic protein denaturation, in addition to the myofiber and connective damage resulting from the eccentric muscle tension. Objective: To identify the effects of dehydration on 5 physiologic characteristics of delayed-onset muscle soreness (DOMS) in normothermic men after an eccentric exercise perturbation. Design: Randomized group test-retest design. Setting: Laboratory. Patients or Other Participants: Ten healthy male volunteers randomly assigned to either a euhydration (age = 26.2 ± 4.9 years, height = 174.1 ± 6.0 cm, mass = 86.5 ± 15.3 kg) or dehydration (age = 25.8 ± 2.2 years, height = 177.2 ± 3.1 cm, mass = 84.4 ± 3.8 kg) group. Intervention(s): Subjects performed treadmill walking for 45 minutes in either a thermoneutral (euhydration) or a hot, humid (dehydration) environment. After a rest period to allow for return to the normothermic condition, DOMS was induced with a 45-minute downhill run. Main Outcome Measures: We assessed 5 physiologic characteristics of DOMS before and at intervals after the eccentric exercise. The characteristics were perceived pain of the bilateral quadriceps and overall body, bilateral punctate tenderness of the superficial quadriceps muscles, bilateral knee-flexion passive range of motion, bilateral thigh circumference, and bilateral isometric quadriceps muscle strength. Thermoregulatory and cardiovascular measures were obtained to monitor participants' heat load during exercise. Results: The experimental protocol produced a 0.9% increase in body mass of the euhydration group and a significant 2.7% decrease in body mass of the dehydration group. The downhill-running exercise perturbation induced DOMS in both the euhydrated and dehydrated participants, based on increased bilateral quadriceps and overall body perceived pain and punctate tenderness of the bilateral vastus medialis

  20. Surviving the cold: molecular analyses of insect cryoprotective dehydration in the Arctic springtail Megaphorura arctica (Tullberg)

    PubMed Central

    Clark, Melody S; Thorne, Michael AS; Purać, Jelena; Burns, Gavin; Hillyard, Guy; Popović, Željko D; Grubor-Lajšić, Gordana; Worland, M Roger

    2009-01-01

    Background Insects provide tractable models for enhancing our understanding of the physiological and cellular processes that enable survival at extreme low temperatures. They possess three main strategies to survive the cold: freeze tolerance, freeze avoidance or cryoprotective dehydration, of which the latter method is exploited by our model species, the Arctic springtail Megaphorura arctica, formerly Onychiurus arcticus (Tullberg 1876). The physiological mechanisms underlying cryoprotective dehydration have been well characterised in M. arctica and to date this process has been described in only a few other species: the Antarctic nematode Panagrolaimus davidi, an enchytraied worm, the larvae of the Antarctic midge Belgica antarctica and the cocoons of the earthworm Dendrobaena octaedra. There are no in-depth molecular studies on the underlying cold survival mechanisms in any species. Results A cDNA microarray was generated using 6,912 M. arctica clones printed in duplicate. Analysis of clones up-regulated during dehydration procedures (using both cold- and salt-induced dehydration) has identified a number of significant cellular processes, namely the production and mobilisation of trehalose, protection of cellular systems via small heat shock proteins and tissue/cellular remodelling during the dehydration process. Energy production, initiation of protein translation and cell division, plus potential tissue repair processes dominate genes identified during recovery. Heat map analysis identified a duplication of the trehalose-6-phosphate synthase (TPS) gene in M. arctica and also 53 clones co-regulated with TPS, including a number of membrane associated and cell signalling proteins. Q-PCR on selected candidate genes has also contributed to our understanding with glutathione-S-transferase identified as the major antioxdidant enzyme protecting the cells during these stressful procedures, and a number of protein kinase signalling molecules involved in recovery

  1. A Puzzling Alcohol Dehydration Reaction Solved by GC-MS Analysis

    NASA Astrophysics Data System (ADS)

    Pelter, Michael W.; Macudzinski, Rebecca M.

    1999-06-01

    We have adapted the dehydration of 2-methyl-2-propanol to a "puzzle" approach for use in our second-semester chemistry major organic laboratory. The reaction of 2-methyl-2-propanol with ~50% sulfuric acid at 100 °C yields isobutylene, which reacts further by a "puzzling" reaction. By coupling the GC/MS analysis of the product mixture with their knowledge of the mechanism of alcohol dehydration and alkene reactivity, students are able to identify the major products of this reaction.

  2. GLYCOL DEHYDRATOR BTEX AND VOC EMISSIONS TESTING RESULTS AT TWO UNITS IN TEXAS AND LOUISIANA VOL. I: TECHNICAL REPORT

    EPA Science Inventory

    The report gives results of the collection of emissions tests data at two triethylene glycol units to provide data for comparison to GRI-GLYCalc, a computer program developed to estimate emissions from glycol dehydrators. (NOTE: Glycol dehydrators are used in the natural gas indu...

  3. GLYCOL DEHYDRATOR BTEX AND VOC EMISSIONS TESTING RESULTS AT TWO UNITS IN TEXAS AND LOUISIANA VOL. II: APPENDICES

    EPA Science Inventory

    The report gives results of the collection of emissions test data st two triethylene glycol units to provide data for the comparison to GRI-GLYCalc, a computer program developed to estimate emissions from glycol dehydrators. [NOTE: Glycol dehydrators are used in the natural gas i...

  4. Heat and Mass Transfer Modeling of Apple Slice under Simultaneous Infrared Dry-Blanching and Dehydration Process

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To develop a new simultaneous infrared dry blanching and dehydration process for producing high-quality blanched and partially dehydrated products, apple slices with three different thicknesses, 5, 9, and 13 mm, were heated using infrared for up to 10 min at 4000W/m2 IR intensity. The surface and ce...

  5. Processing and Quality Characteristics of Apple Slices under Simultaneous Infrared Dry-blanching and Dehydration with Intermittent Heating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the effects of three processing parameters, e.g. product surface temperature, slice thickness and processing time, on blanching and dehydration characteristics of apple slices exposed to simultaneous infrared dry-blanching and dehydration (SIRDBD) with intermittent heating. A...

  6. Quantitative analysis of dehydration in porcine skin caused by optical clearing agents

    NASA Astrophysics Data System (ADS)

    Yu, Tingting; Wen, Xiang; Duan, Shu; Zhu, Dan

    2010-11-01

    Dehydration is supposed to be one of mechanisms of optical clearing, but current studies merely gave some qualitative descriptions. Here an analysis method was established to evaluate the water content of skin with PLS method based on the measurements of near-infrared reflectance spectroscopy and weight of porcine skin. Furthermore, a commercial spectrometer with integrating sphere was used to measure the reflectance and transmittance after treatment with different agents. Then the established method was used to evaluate the water content, while the Inverse Adding-Double algorithm was used to calculate the reduced scattering coefficients. The results show that both the water contents and reduced scattering coefficients decrease during the optical clearing process, and there is direct relationship between the optical clearing efficacy and dehydration. With the treating time last, the relative change in reduced scattering coefficient is larger than that in dehydration of skin, and the difference between the changes depends on the agents. Therefore, we conclude that dehydration is the main mechanism of skin optical clearing during the 60 min treatment of the agents, but for some OCAs, i.e., PEG400, glycerol, or D-sorbitol, there might be some other mechanisms contributing to the optical clearing efficacy.

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

    PubMed

    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.

  8. Dehydration and vernalization treatments identify overlapping molecular networks impacting endodormancy maintenance in leafy spurge crown buds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leafy spurge (Euphorbia esula L.) is an herbaceous perennial weed that reproduces vegetatively from an abundance of underground adventitious buds (UABs), which undergo well-defined phases of seasonal dormancy (para-, endo- and eco-dormancy). In this study, the effects of dehydration-stress on vegeta...

  9. Dehydration of the Upper Troposphere and Lower Stratosphere by Subvisible Cirrus Clouds Near the Tropical Tropopause

    NASA Technical Reports Server (NTRS)

    Jensen, Eric J.; Toon, Owen B.; Pfister, Leonhard; Selkirk, Henry B.

    1996-01-01

    The extreme dryness of the lower stratosphere is believed to be caused by freeze-drying of air as it enters the stratosphere through the cold tropical tropopause. Previous investigations have been focused on dehydration occurring at the tops of deep convective cloud systems, However, recent observations of a ubiquitous stratiform cirrus cloud layer near the tropical tropopause suggest the possibility of dehydration as air is slowly lifted by large-scale motions, In this study, we have evaluated this possibility using a detailed ice cloud model. Simulations of ice cloud formation in the temperature minima of gravity waves (wave periods of 1 - 2 hours) indicate that large numbers of ice crystals will likely form due to the low temperatures and rapid cooling. As a result, the crystals do not grow larger than about 10 microns, fallspeeds are no greater than a few cm/s, and little or no precipitation or dehydration occurs. However, ice cloud's formed by large-scale vertical motions (with lifetimes of a day or more) should have,fever crystals and more time for crystal sedimentation to occur, resulting in water vapor depletions as large as 1 ppmv near the tropopause. We suggest that gradual lifting near the tropical tropopause, accompanied by formation of thin cirrus, may account for the dehydration.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Mechanistic insights into aqueous phase propanol dehydration in H-ZSM-5 zeolite

    SciTech Connect

    Mei, Donghai; Lercher, Johannes A.

    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.

  12. Fragmentation of chloroperoxides: hypochlorite-mediated dehydration of hydroperoxyacetals to esters

    PubMed Central

    Fisher, Thomas J.; Dussault, Patrick H.

    2010-01-01

    Hypochlorites efficently dehydrate hydroperoxyacetals to furnish the corresponding esters. The reaction, which can be accomplished with stoichometric Ca(OCl)2 or with catalytic amounts of t-BuOCl, appears to involve formation and heterolytic fragmentation of secondary chloroperoxides, species not previously described in solution chemistry. PMID:20865135

  13. Pervaporation process and use in treating waste stream from glycol dehydrator

    DOEpatents

    Kaschemekat, Jurgen; Baker, Richard W.

    1994-01-01

    Pervaporation processes and apparatus with few moving parts. Ideally, only one pump is used to provide essentially all of the motive power and driving force needed. The process is particularly useful for handling small streams with flow rates less than about 700 gpd. Specifically, the process can be used to treat waste streams from glycol dehydrator regeneration units.

  14. Dehydration, rehydration and overhydration alter patterns of gene expression in the Antarctic midge, Belgica antarctica

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated molecular responses elicited by three types of dehydration (fast, slow and cryoprotective), rehydration and overhydration in larvae of the Antarctic midge, Belgica antarctica. The larvae spend most the year encased in ice but during the austral summer are vulnerable to summer storms,...

  15. Water replacement hypothesis in atomic detail--factors determining the structure of dehydrated bilayer stacks.

    PubMed

    Golovina, Elena A; Golovin, Andrey V; Hoekstra, Folkert A; Faller, Roland

    2009-07-22

    According to the water replacement hypothesis, trehalose stabilizes dry membranes by preventing the decrease of spacing between membrane lipids under dehydration. In this study, we use molecular-dynamics simulations to investigate the influence of trehalose on the area per lipid (APL) and related structural properties of dehydrated bilayers in atomic detail. The starting conformation of a palmitoyloleolylphosphatidylcholine lipid bilayer in excess water was been obtained by self-assembly. A series of molecular-dynamics simulations of palmitoyloleolylphosphatidylcholine with different degrees of dehydration (28.5, 11.7, and 5.4 waters per lipid) and different molar trehalose/lipid ratios (<1:1, 1:1, and >1:1) were carried out in the NPT ensemble. Water removal causes the formation of multilamellar "stacks" through periodic boundary conditions. The headgroups reorient from pointing outward to inward with dehydration. This causes changes in the electrostatic interactions between interfaces, resulting in interface interpenetration. Interpenetration creates self-spacing of the bilayers and prevents gel-phase formation. At lower concentrations, trehalose does not separate the interfaces, and acting together with self-spacing, it causes a considerable increase of APL. APL decreases at higher trehalose concentrations when the layer of sugar physically separates the interfaces. When interfaces are separated, the model confirms the water replacement hypothesis.

  16. Water Replacement Hypothesis in Atomic Detail—Factors Determining the Structure of Dehydrated Bilayer Stacks

    PubMed Central

    Golovina, Elena A.; Golovin, Andrey V.; Hoekstra, Folkert A.; Faller, Roland

    2009-01-01

    Abstract According to the water replacement hypothesis, trehalose stabilizes dry membranes by preventing the decrease of spacing between membrane lipids under dehydration. In this study, we use molecular-dynamics simulations to investigate the influence of trehalose on the area per lipid (APL) and related structural properties of dehydrated bilayers in atomic detail. The starting conformation of a palmitoyloleolylphosphatidylcholine lipid bilayer in excess water was been obtained by self-assembly. A series of molecular-dynamics simulations of palmitoyloleolylphosphatidylcholine with different degrees of dehydration (28.5, 11.7, and 5.4 waters per lipid) and different molar trehalose/lipid ratios (<1:1, 1:1, and >1:1) were carried out in the NPT ensemble. Water removal causes the formation of multilamellar “stacks” through periodic boundary conditions. The headgroups reorient from pointing outward to inward with dehydration. This causes changes in the electrostatic interactions between interfaces, resulting in interface interpenetration. Interpenetration creates self-spacing of the bilayers and prevents gel-phase formation. At lower concentrations, trehalose does not separate the interfaces, and acting together with self-spacing, it causes a considerable increase of APL. APL decreases at higher trehalose concentrations when the layer of sugar physically separates the interfaces. When interfaces are separated, the model confirms the water replacement hypothesis. PMID:19619463

  17. 40 CFR 63.765 - Glycol dehydration unit process vent standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... directly to the atmosphere may be used on the air emission control equipment installed to comply with... satisfaction, that the total HAP emissions to the atmosphere from the glycol dehydration unit process vent are... demonstrates, to the Administrator's satisfaction, that total emissions to the atmosphere from the...

  18. Proteome analysis of leaves from the resurrection plant Boea hygrometrica in response to dehydration and rehydration.

    PubMed

    Jiang, Guoqiang; Wang, Zhi; Shang, Haihong; Yang, Wenlong; Hu, Zhiang; Phillips, Jonathan; Deng, Xin

    2007-05-01

    Resurrection plants differ from other species in their unique ability to survive desiccation. In order to understand the mechanisms of desiccation tolerance, proteome studies were carried out using leaves of the resurrection plant Boea hygrometrica to reveal proteins that were differentially expressed in response to changes in relative water content. This opportunity was afforded by the rare ability of excised B. hygrometrica leaves to survive and resume metabolism following desiccation in a manner similar to intact plants. From a total of 223 proteins that were reproducibly detected and analyzed, 35% showed increased abundance in dehydrated leaves, 5% were induced in rehydrated leaves and 60% showed decreased or unchanged abundance in dehydrated and rehydrated leaves. Since the induction kinetics fall into clearly defined patterns, we suggest that programmed regulation of protein expression triggered by changes of water status. Fourteen dehydration responsive proteins were analyzed by mass spectrometry. Eight proteins were classified as playing a role in reactive oxygen species scavenging, photosynthesis and energy metabolism. In agreement with these findings, glutathione content and polyphenol oxidase activity were found to increase upon dehydration and rapid recovery of photosynthesis was observed.

  19. Hypernatremia in the Neonate: Neonatal Hypernatremia and Hypernatremic Dehydration in Neonates Receiving Exclusive Breastfeeding

    PubMed Central

    Mujawar, Nilofer Salim; Jaiswal, Archana Nirmal

    2017-01-01

    Aims and Objectives: Evaluation of neonatal hypernatremia and hypernatremic dehydration in neonates receiving exclusive breastfeeding. Introduction: Neonatal hypernatremia is a serious condition in the newborn period. We present infants with hypernatremic dehydration due to breast milk (BM) hypernatremia. Hypernatremic dehydration in breast-fed newborns is usually secondary to insufficient lactation. We present the neonatal hypernatremia and hypernatremic dehydration encountered between January and December, 2012, its causes and treatment. Methodology: This was a retrospective study. We analyzed records of babies admitted to the Neonatal Intensive Care Unit who were investigated and found to have hypernatremia and whose mother's BM sodium (BM Na) was done. Inclusion Criteria: (1) Babies with serum Na >145 meq/l, (2) euglycemia, (3) normocalcemic, (4) no clinical and lab evidence of sepsis, (5) exclusive breast feeds. Exclusion Criteria: Neonates not satisfying any mentioned criterion. Results: BM Na correlated strongly with neonatal hypernatremia in exclusively breast-fed babies who did not otherwise have any risk factor. Conclusion: Elevated BM Na is an important etiological factor in neonatal hypernatremia. PMID:28197048

  20. Dehydration of post-mortem eyes for practice and experimental surgery.

    PubMed

    Swinger, C A; Kornmehl, E W

    1985-03-01

    A technique has been developed that allows for rapid dehydration of the cornea of an intact globe. This technique results in a marked improvement in corneal clarity and visualization of anterior chamber structures. Treated eyes can be used for practice and experimental surgery.

  1. Leveraging the micellar effect: gold-catalyzed dehydrative cyclizations in water at room temperature.

    PubMed

    Minkler, Stefan R K; Isley, Nicholas A; Lippincott, Daniel J; Krause, Norbert; Lipshutz, Bruce H

    2014-02-07

    The first examples of gold-catalyzed cyclizations of diols and triols to the corresponding hetero- or spirocycles in an aqueous medium are presented. These reactions take place within nanomicelles, where the hydrophobic effect is operating, thereby driving the dehydrations, notwithstanding the surrounding water. By the addition of simple salts such as sodium chloride, reaction times and catalyst loadings can be significantly decreased.

  2. A Triple Iron Triathlon Leads to a Decrease in Total Body Mass but Not to Dehydration

    ERIC Educational Resources Information Center

    Knechtle, Beat; Knechtle, Patrizia; Rosemann, Thomas; Oliver, Senn

    2010-01-01

    A loss in total body mass during an ultraendurance performance is usually attributed to dehydration. We identified the changes in total body mass, fat mass, skeletal muscle mass, and selected markers of hydration status in 31 male nonprofessional ultratriathletes participating in a Triple Iron triathlon involving 11.4 km swimming, 540 km cycling…

  3. Florida initiative aims to slash unnecessary admissions due to 'catch-all' dehydration diagnosis.

    PubMed

    2001-05-01

    When the peer review organization in Florida sounded an alarm about unnecessary medical admissions with the diagnosis of dehydration, a Tampa hospital decided to make the issue a priority. Although St. Joseph's Hospital was performing better than average, it still found ways to reduce the number of inappropriate admissions and improve related outcome measures.

  4. Polymeric blend nanocomposite membranes for ethanol dehydration-effect of morphology and membrane-solvent interactions

    EPA Science Inventory

    Nanocomposite membranes (NCMs) of sodium alginate/poly(vinyl pyrrolidone) blend polymers incorporated with varying concentrations of phosphotungstic acid (H3PW12O40) (PWA) nanoparticles have been prepared and used in ethanol dehydration by the pervaporation (PV) technique. Effe...

  5. 21 CFR 573.400 - Ethoxyquin in certain dehydrated forage crops.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... and vitamin E in the forage crops. (c) It is added to the dehydrated forage crops in an oil mixture... preservative,” or “Ethoxyquin added to retard the oxidative destruction of carotene and vitamin E.” (2)...

  6. Anhydrobiosis in yeast: cell wall mannoproteins are important for yeast Saccharomyces cerevisiae resistance to dehydration.

    PubMed

    Borovikova, Diana; Teparić, Renata; Mrša, Vladimir; Rapoport, Alexander

    2016-08-01

    The state of anhydrobiosis is linked with the reversible delay of metabolism as a result of strong dehydration of cells, and is widely distributed in nature. A number of factors responsible for the maintenance of organisms' viability in these conditions have been revealed. This study was directed to understanding how changes in cell wall structure may influence the resistance of yeasts to dehydration-rehydration. Mutants lacking various cell wall mannoproteins were tested to address this issue. It was revealed that mutants lacking proteins belonging to two structurally and functionally unrelated groups (proteins non-covalently attached to the cell wall, and Pir proteins) possessed significantly lower cell resistance to dehydration-rehydration than the mother wild-type strain. At the same time, the absence of the GPI-anchored cell wall protein Ccw12 unexpectedly resulted in an increase of cell resistance to this treatment; this phenomenon is explained by the compensatory synthesis of chitin. The results clearly indicate that the cell wall structure/composition relates to parameters strongly influencing yeast viability during the processes of dehydration-rehydration, and that damage to cell wall proteins during yeast desiccation can be an important factor leading to cell death. Copyright © 2016 John Wiley & Sons, Ltd.

  7. 40 CFR 63.1275 - Glycol dehydration unit process vent standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... National Emission Standards for Hazardous Air Pollutants From Natural Gas Transmission and Storage... dehydration unit subject to this subpart with an actual annual average natural gas flowrate equal to or... connecting the process vent to a process natural gas line. (2) The owner or operator shall demonstrate,...

  8. 40 CFR 63.1275 - Glycol dehydration unit process vent standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... National Emission Standards for Hazardous Air Pollutants From Natural Gas Transmission and Storage... dehydration unit subject to this subpart with an actual annual average natural gas flowrate equal to or... connecting the process vent to a process natural gas line. (2) The owner or operator shall demonstrate,...

  9. 40 CFR 63.1275 - Glycol dehydration unit process vent standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... National Emission Standards for Hazardous Air Pollutants From Natural Gas Transmission and Storage... dehydration unit subject to this subpart with an actual annual average natural gas flowrate equal to or... connecting the process vent to a process natural gas line. (2) The owner or operator shall demonstrate,...

  10. 40 CFR 63.1275 - Glycol dehydration unit process vent standards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) National Emission Standards for Hazardous Air Pollutants From Natural Gas Transmission and... average daily natural gas throughput, standard cubic meters per day; Ci,BTEX = Annual average BTEX concentration of the natural gas at the inlet to the glycol dehydration unit, ppmv. ER16AU12.013 Where:...

  11. 40 CFR 63.1275 - Glycol dehydration unit process vent standards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) National Emission Standards for Hazardous Air Pollutants From Natural Gas Transmission and... average daily natural gas throughput, standard cubic meters per day; Ci,BTEX = Annual average BTEX concentration of the natural gas at the inlet to the glycol dehydration unit, ppmv. ER16AU12.013 Where:...

  12. Hydrous mineral dehydration around heat-generating nuclear waste in bedded salt formations.

    PubMed

    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.

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

    PubMed

    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 < 0.01). The MAP and HR responses were not different between treatments (both 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.

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

    PubMed

    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, p<0.02). The mean difference in the fluid deficit calculated was 4.0% of body weight (95% CI: 3.2-4.7, p<0.0001). Theoretical weight overestimated accurate pre-illness weight by 0.21 kg (95% CI: 0.08-0.34, p = 0.002). Post-illness weight underestimated pre-illness weight by 0.19 kg (95% CI: 0.03-0.36, p = 0.02). The prevalence of 5% dehydration according to post-illness weight (21%) was significantly lower than the prevalence estimated by either theoretical weight (60%) or clinical assessment (66%, p<0.0001).These data suggest that post-illness weight is of little value as a gold standard to determine the true level of dehydration. The performance of dehydration signs or scales determined by using post-illness weight as a gold standard has to be reconsidered.

  15. Hydrogen peroxide and ecdysone in the cryoprotective dehydration strategy of Megaphorura arctica (Onychiuridae: Collembola).

    PubMed

    Grubor-Lajšić, Gordana; Petri, Edward T; Kojić, Danijela; Purać, Jelena; Popović, Zeljko D; Worland, Roger M; Clark, Melody S; Mojović, Miloš; Blagojević, Duško P

    2013-02-01

    The Arctic springtail, Megaphorura arctica, survives sub-zero temperatures in a dehydrated state via trehalose-dependent cryoprotective dehydration. Regulation of trehalose biosynthesis is complex; based in part on studies in yeast and fungi, its connection with oxidative stress caused by exposure of cells to oxidants, such as hydrogen peroxide (H₂O₂), or dehydration, is well documented. In this respect, we measured the amount of H₂O₂ and antioxidant enzyme activities (superoxide dismutases: copper, zinc--CuZnSOD and manganese containing--MnSOD, and catalase--CAT), as the regulatory components determining H₂O₂ concentrations, in Arctic springtails incubated at 5 °C (control) versus -2 °C (threshold temperature for trehalose biosynthesis). Because ecdysone also stimulates trehalose production in insects and regulates the expression of genes involved in redox homeostasis and antioxidant protection in Drosophila, we measured the levels of the active physiological form of ecdysone--20-hydroxyecdysone (20-HE). Significantly elevated H₂O₂ and 20-HE levels were observed in M. arctica incubated at -2 °C, supporting a link between ecdysone, H₂O₂, and trehalose levels during cryoprotective dehydration. CAT activity was found to be significantly lower in M. arctica incubated at -2 °C versus 5 °C, suggesting reduced H₂O₂ breakdown. Furthermore, measurement of the free radical composition in Arctic springtails incubated at 5 °C (controls) versus -2 °C by Electron Paramagnetic Resonance spectroscopy revealed melanin-derived free radicals at -2 °C, perhaps an additional source of H₂O₂. Our results suggest that H₂O₂ and ecdysone play important roles in the cryoprotective dehydration process in M. arctica, linked with the regulation of trehalose biosynthesis.

  16. Influence of progressive fluid restriction on mood and physiological markers of dehydration in women.

    PubMed

    Pross, Nathalie; Demazières, Agnès; Girard, Nicolas; Barnouin, Romain; Santoro, Francine; Chevillotte, Emmanuel; Klein, Alexis; Le Bellego, Laurent

    2013-01-28

    The present study evaluated, using a well-controlled dehydration protocol, the effects of 24 h fluid deprivation (FD) on selected mood and physiological parameters. In the present cross-over study, twenty healthy women (age 25 (SE 0.78) years) participated in two randomised sessions: FD-induced dehydration v. a fully hydrated control condition. In the FD period, the last water intake was between 18.00 and 19.00 hours and no beverages were allowed until 18.00 hours on the next day (23-24 h). Water intake was only permitted at fixed periods during the control condition. Physiological parameters in the urine, blood and saliva (osmolality) as well as mood and sensations (headache and thirst) were compared across the experimental conditions. Safety was monitored throughout the study. The FD protocol was effective as indicated by a significant reduction in urine output. No clinical abnormalities of biological parameters or vital signs were observed, although heart rate was increased by FD. Increased urine specific gravity, darker urine colour and increased thirst were early markers of dehydration. Interestingly, dehydration also induced a significant increase in saliva osmolality at the end of the 24 h FD period but plasma osmolality remained unchanged. The significant effects of FD on mood included decreased alertness and increased sleepiness, fatigue and confusion. The most consistent effects of mild dehydration on mood are on sleep/wake parameters. Urine specific gravity appears to be the best physiological measure of hydration status in subjects with a normal level of activity; saliva osmolality is another reliable and non-invasive method for assessing hydration status.

  17. Dehydration effects from contrails in a coupled contrail-climate model

    NASA Astrophysics Data System (ADS)

    Schumann, U.; Penner, J. E.; Chen, Yibin; Zhou, Cheng; Graf, K.

    2015-10-01

    The uptake of water by contrails in ice-supersaturated air and the release of water after ice particle advection and sedimentation dehydrates the atmosphere at flight levels and redistributes humidity mainly to lower levels. The dehydration is investigated by coupling a plume-scale contrail model with a global aerosol-climate model. The contrail model simulates all the individual contrails forming from global air traffic for meteorological conditions as defined by the climate model. The computed contrail cirrus properties compare reasonably with theoretical concepts and observations. The mass of water in aged contrails may exceed 106 times the mass of water emitted from aircraft. Many of the ice particles sediment and release water in the troposphere, on average 700 m below the mean flight levels. Simulations with and without coupling are compared. The drying at contrail levels causes thinner and longer-lived contrails with about 15 % reduced contrail radiative forcing (RF). The reduced RF from contrails is on the order of 0.06 W m-2, slightly larger than estimated earlier because of higher soot emissions. For normal traffic, the RF from dehydration is small compared to interannual variability. A case with emissions increased by 100 times is used to overcome statistical uncertainty. The contrails impact the entire hydrological cycle in the atmosphere by reducing the total water column and the cover by high- and low-level clouds. For normal traffic, the dehydration changes contrail RF by positive shortwave and negative longwave contributions on the order of 0.04 W m-2, with a small negative net RF. The total net RF from contrails and dehydration remains within the range of previous estimates.

  18. Dehydration effects from contrails in a coupled contrail-climate model

    NASA Astrophysics Data System (ADS)

    Schumann, U.; Penner, J. E.; Chen, Y.; Zhou, C.; Graf, K.

    2015-07-01

    Uptake of water by contrails in ice-supersaturated air and release of water after ice particle advection and sedimentation dehydrates the atmosphere at flight levels and redistributes humidity mainly to lower levels. The dehydration is investigated by coupling a plume-scale contrail model with a global aerosol-climate model. The contrail model simulates all the individual contrails forming from global air traffic for meteorological conditions as defined by the climate model. The computed contrail-cirrus properties compare reasonably with theoretical concepts and observations. The mass of water in aged contrails may exceed 106 times the mass of water emitted from aircraft. Many of the ice particles sediment and release water in the troposphere, on average 700 m below the mean flight levels. Simulations with and without coupling are compared. The drying at contrail levels causes thinner and longer lived contrails with about 15 % reduced contrail radiative forcing (RF). The reduced RF from contrails is of the order 0.06 W m-2, slightly larger than estimated earlier because of higher soot emissions. For normal traffic, the RF from dehydration is small compared to interannual variability. A case with 100 times increased emissions is used to overcome statistical uncertainty. The contrails impact the entire hydrological cycle in the atmosphere by reducing the total water column and the cover of high and low-level clouds. For normal traffic, the dehydration changes contrail RF by positive shortwave and negative longwave contributions of order 0.04 W m-2, with a small negative net RF. The total net RF from contrails and dehydration remains within the range of previous estimates.

  19. Tracking the dehydration process of raw honey by synchronous two-dimensional near infrared correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Guiyun; Sun, Xin; Huang, Yuping; Chen, Kunjie

    2014-11-01

    Though much attention is paid to honey quality assessment, few reports on characteristic of manually dehydrated honey have been found. The aim of this investigation is to track the dehydration process of raw honey using synchronous two-dimensional (2D) near infrared correlation spectroscopy. To minimize the impact of dehydration to honey quality, seventy-two honey samples from six different dehydration stages were obtained using drum wind drying method with temperature controlled at 40 °C. Their dynamic short-wave NIR spectra from 600 to 1100 nm were collected in the transmission mode from 10 to 50 °C with an increment of 5 °C and were analyzed using synchronous two-dimensional correlation method. Short-wave NIR spectral data has been exploited less than other NIR region for its weaker signal especially for water absorption's interference with useful information. The investigation enlarged the signal at this band using synchronous 2D correlation analysis, revealing the fingerprinting feature of rape honey and chaste honey during the artificial dehydration process. The results have shown that, with the help of 2D correlation analysis, this band can detect the variation of the second overtone of O-H and N-H groups vibration upon their H-bonds forming or collapsing resulted from the interactions between water and solute. The results have also shown that 2D-NIRS method is able to convert the tiny changes in honey constituents into the detectable fingerprinting difference, which provides a new method for assessing honey quality.

  20. Leaf Shrinkage with Dehydration: Coordination with Hydraulic Vulnerability and Drought Tolerance1[C][W][OPEN

    PubMed Central

    Scoffoni, Christine; Vuong, Christine; Diep, Steven; Cochard, Hervé; Sack, Lawren

    2014-01-01

    Leaf shrinkage with dehydration has attracted attention for over 100 years, especially as it becomes visibly extreme during drought. However, little has been known of its correlation with physiology. Computer simulations of the leaf hydraulic system showed that a reduction of hydraulic conductance of the mesophyll pathways outside the xylem would cause a strong decline of leaf hydraulic conductance (Kleaf). For 14 diverse species, we tested the hypothesis that shrinkage during dehydration (i.e. in whole leaf, cell and airspace thickness, and leaf area) is associated with reduction in Kleaf at declining leaf water potential (Ψleaf). We tested hypotheses for the linkage of leaf shrinkage with structural and physiological water relations parameters, including modulus of elasticity, osmotic pressure at full turgor, turgor loss point (TLP), and cuticular conductance. Species originating from moist habitats showed substantial shrinkage during dehydration before reaching TLP, in contrast with species originating from dry habitats. Across species, the decline of Kleaf with mild dehydration (i.e. the initial slope of the Kleaf versus Ψleaf curve) correlated with the decline of leaf thickness (the slope of the leaf thickness versus Ψleaf curve), as expected based on predictions from computer simulations. Leaf thickness shrinkage before TLP correlated across species with lower modulus of elasticity and with less negative osmotic pressure at full turgor, as did leaf area shrinkage between full turgor and oven desiccation. These findings point to a role for leaf shrinkage in hydraulic decline during mild dehydration, with potential impacts on drought adaptation for cells and leaves, influencing plant ecological distributions. PMID:24306532

  1. The effects of dehydration, moderate alcohol consumption, and rehydration on cognitive functions.

    PubMed

    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.

  2. Effect of hydrothermal circulation on slab dehydration for the subduction zone of Costa Rica and Nicaragua

    NASA Astrophysics Data System (ADS)

    Rosas, Juan Carlos; Currie, Claire A.; Harris, Robert N.; He, Jiangheng

    2016-06-01

    Dehydration of subducting oceanic plates is associated with mantle wedge melting, arc volcanism, intraslab earthquakes through dehydration embrittlement, and the flux of water into the mantle. In this study, we present two-dimensional thermal models of the Costa Rica-Nicaragua subduction zone to investigate dehydration reactions within the subducting Cocos plate. Seismic and geochemical observations indicate that the mantle wedge below Nicaragua is more hydrated than that below Costa Rica. These trends have been hypothesized to be due to a variation in either the thermal state or the hydration state of the subducting slab. Despite only small variations in plate age along strike, heat flow measurements near the deformation front reveal significantly lower heat flow offshore Nicaragua than offshore Costa Rica. These measurements are interpreted to reflect an along-strike change in the efficiency of hydrothermal circulation in the oceanic crust. We parameterize thermal models in terms of efficient and inefficient hydrothermal circulation and explore their impact on slab temperature in the context of dehydration models. Relative to models without fluid flow, efficient hydrothermal circulation reduces slab temperature by as much at 60 °C to depths of ∼75 km and increases the predicted depth of eclogitization by ∼15 km. Inefficient hydrothermal circulation has a commensurately smaller influence on slab temperatures and the depth of eclogitization. For both regions, the change in eclogitization depth better fits the observed intraslab crustal seismicity, but there is not a strong contrast in the slab thermal structure or location of the main dehydration reactions. Consistent with other studies, these results suggest that observed along-strike differences in mantle wedge hydration may be better explained by a northwestward increase in the hydration state of the Cocos plate before it is subducted.

  3. Outside-Xylem Vulnerability, Not Xylem Embolism, Controls Leaf Hydraulic Decline during Dehydration.

    PubMed

    Scoffoni, Christine; Albuquerque, Caetano; Brodersen, Craig R; Townes, Shatara V; John, Grace P; Bartlett, Megan K; Buckley, Thomas N; McElrone, Andrew J; Sack, Lawren

    2017-02-01

    Leaf hydraulic supply is crucial to maintaining open stomata for CO2 capture and plant growth. During drought-induced dehydration, the leaf hydraulic conductance (Kleaf) declines, which contributes to stomatal closure and, eventually, to leaf death. Previous studies have tended to attribute the decline of Kleaf to embolism in the leaf vein xylem. We visualized at high resolution and quantified experimentally the hydraulic vulnerability of xylem and outside-xylem pathways and modeled their respective influences on plant water transport. Evidence from all approaches indicated that the decline of Kleaf during dehydration arose first and foremost due to the vulnerability of outside-xylem tissues. In vivo x-ray microcomputed tomography of dehydrating leaves of four diverse angiosperm species showed that, at the turgor loss point, only small fractions of leaf vein xylem conduits were embolized, and substantial xylem embolism arose only under severe dehydration. Experiments on an expanded set of eight angiosperm species showed that outside-xylem hydraulic vulnerability explained 75% to 100% of Kleaf decline across the range of dehydration from mild water stress to beyond turgor loss point. Spatially explicit modeling of leaf water transport pointed to a role for reduced membrane conductivity consistent with published data for cells and tissues. Plant-scale modeling suggested that outside-xylem hydraulic vulnerability can protect the xylem from tensions that would induce embolism and disruption of water transport under mild to moderate soil and atmospheric droughts. These findings pinpoint outside-xylem tissues as a central locus for the control of leaf and plant water transport during progressive drought.

  4. Leaf shrinkage with dehydration: coordination with hydraulic vulnerability and drought tolerance.

    PubMed

    Scoffoni, Christine; Vuong, Christine; Diep, Steven; Cochard, Hervé; Sack, Lawren

    2014-04-01

    Leaf shrinkage with dehydration has attracted attention for over 100 years, especially as it becomes visibly extreme during drought. However, little has been known of its correlation with physiology. Computer simulations of the leaf hydraulic system showed that a reduction of hydraulic conductance of the mesophyll pathways outside the xylem would cause a strong decline of leaf hydraulic conductance (K(leaf)). For 14 diverse species, we tested the hypothesis that shrinkage during dehydration (i.e. in whole leaf, cell and airspace thickness, and leaf area) is associated with reduction in K(leaf) at declining leaf water potential (Ψ(leaf)). We tested hypotheses for the linkage of leaf shrinkage with structural and physiological water relations parameters, including modulus of elasticity, osmotic pressure at full turgor, turgor loss point (TLP), and cuticular conductance. Species originating from moist habitats showed substantial shrinkage during dehydration before reaching TLP, in contrast with species originating from dry habitats. Across species, the decline of K(leaf) with mild dehydration (i.e. the initial slope of the K(leaf) versus Ψ(leaf) curve) correlated with the decline of leaf thickness (the slope of the leaf thickness versus Ψ(leaf) curve), as expected based on predictions from computer simulations. Leaf thickness shrinkage before TLP correlated across species with lower modulus of elasticity and with less negative osmotic pressure at full turgor, as did leaf area shrinkage between full turgor and oven desiccation. These findings point to a role for leaf shrinkage in hydraulic decline during mild dehydration, with potential impacts on drought adaptation for cells and leaves, influencing plant ecological distributions.

  5. Metabolic Dysfunction and Unabated Respiration Precede the Loss of Membrane Integrity during Dehydration of Germinating Radicles1

    PubMed Central

    Leprince, Olivier; Harren, Frans J.M.; Buitink, Julia; Alberda, Mark; Hoekstra, Folkert A.

    2000-01-01

    This study shows that dehydration induces imbalanced metabolism before loss of membrane integrity in desiccation-sensitive germinated radicles. Using a photoacoustic detection system, responses of CO2 emission and fermentation to drying were analyzed non-invasively in desiccation-tolerant and -intolerant radicles of cucumber (Cucumis sativa) and pea (Pisum sativum). Survival after drying and a membrane integrity assay showed that desiccation tolerance was present during early imbibition and lost in germinated radicles. However, tolerance could be re-induced in germinated cucumber radicles by incubation in polyethylene glycol before drying. Tolerant and polyethylene glycol (PEG)-induced tolerant radicles exhibited a much-reduced CO2 production before dehydration compared with desiccation-sensitive radicles. This difference was maintained during dehydration. In desiccation-sensitive tissues, dehydration induced an increase in the emission of acetaldehyde and ethanol that peaked well before the loss of membrane integrity. Acetaldehyde emission from sensitive radicles was significantly reduced when dehydration occurred in 50% O2 instead of air. Acetaldehyde/ethanol were not detected in dehydrating tolerant radicles of either species or in polyethylene glycol-induced tolerant cucumber radicles. Thus, a balance between down-regulation of metabolism during drying and O2 availability appears to be associated with desiccation tolerance. Using Fourier transform infrared spectroscopy, acetaldehyde was found to disturb the phase behavior of phospholipid vesicles, suggesting that the products resulting from imbalanced metabolism in seeds may aggravate membrane damage induced by dehydration. PMID:10677452

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

    PubMed Central

    Modi, Payal; Glavis-Bloom, Justin; Nasrin, Sabiha; Guy, Allysia; Rege, Soham; Noble, Vicki E.; Alam, Nur H.; Levine, Adam C.

    2016-01-01

    Introduction 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. Objective To assess the accuracy of point-of-care ultrasound measurement of the aorta-to-IVC ratio as a predictor of dehydration in children. Methods 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. Results 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. Conclusions 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. PMID:26766306

  7. Role of iron content on serpentinite dehydration depth in subduction zones: Experiments and thermodynamic modeling

    NASA Astrophysics Data System (ADS)

    Merkulova, Margarita; Muñoz, Manuel; Vidal, Olivier; Brunet, Fabrice

    2016-11-01

    A series of dehydration experiments in the piston-cylinder apparatus was carried out at 2 GPa and 550-850 °C on a natural antigorite sample mixed with 5 wt.% of magnetite. Chemical analyses of experimental products show a progressive decrease of the Mg# in antigorite and clinopyroxene between 550 and 675 °C, whereas the Mg# of olivine increases. The observed behavior of Mg# signifies Fe-Mg exchange between coexisting minerals. At higher temperatures, between 700 and 850 °C, compositions remain stable for all minerals in experimental assemblages. Thermodynamic parameters of the ferrous antigorite end-member were refined with the use of Holland and Powell (1998) data set and added to the antigorite solid solution. Good agreement between theoretical calculations performed for the studied bulk composition and experimental results confirms extrapolated thermodynamic data for Fe-antigorite. Constrained parameters allowed to calculate phase relationships for various serpentinite compositions. First, we assessed the effect of bulk iron content, from 0 to 10 wt.% FeO, on the stability field of antigorite. The results show significant decrease of the antigorite thermal stability with increasing bulk Fe content. Second, we demonstrated the influence of bulk iron content on dehydration reactions in subduction zones along typical thermal gradients. Dehydration observed in pure MSH (MgO-SiO2-H2O) systems comprised of antigorite appears as a univariant reaction, which happens at 710 °C/3.7 GPa and 640 °C/6 GPa in "hot" and "cold" subduction, respectively. In contrast, more complex in composition Fe-bearing serpentinites show spread dehydration profiles through divariant reactions from 300 °C/0.8 GPa to 700 °C/3.6 GPa and from 450 °C/4 GPa to 650 °C/7.4 GPa for "hot" and "cold" thermal gradients respectively. A comparison between depths of "water-release events" and "earthquake occurrence" in the South Chile slab ("hot" subduction) highlights a clear correlation between

  8. Proteome analysis of leaves of the desiccation-tolerant grass, Sporobolus stapfianus, in response to dehydration.

    PubMed

    Oliver, Melvin J; Jain, Renuka; Balbuena, Tiago S; Agrawal, Ganesh; Gasulla, Franscisco; Thelen, Jay J

    2011-07-01

    Drought and its affects on agricultural production is a serious issue facing global efforts to increase food supplies and ensure food security for the growing world population. Understanding how plants respond to dehydration is an important prerequisite for developing strategies for crop improvement in drought tolerance. This has proved to be a difficult task as all of the current research plant models do not tolerate cellular dehydration well and, like all crops, they succumb to the effects of a relatively small water deficit of -4MPa or less. For these reasons many researchers have started to investigate the usefulness of resurrection plants, plants that can survive extremes of dehydration to the point of desiccation, to provide answers as to how plants tolerate water loss. We have chosen to investigate the leaf proteome response of the desiccation-tolerant grass Sporobolus stapfianus Gandoger to dehydration to a water content that encompasses the initiation of the cellular protection response evident in these plants. We used a combination of two-dimensional Difference Gel Electrophoresis (2D-DIGE) and liquid chromatography-tandem-mass spectrometry to compare the proteomes of young leaves from hydrated plants to those dehydrated to approximately 30% relative water content. High-resolution 2D-DIGE revealed 96 significantly different proteins and 82 of these spots yielded high-quality protein assignments by tandem-mass spectrometry. Inferences from the bioinformatic annotations of these proteins revealed the possible involvement of protein kinase-based signaling cascades and brassinosteroid involvement in the regulation of the cellular protection response. Enzymes of glycolysis, both cytoplasmic and plastidic, as well as five enzymes of the Calvin cycle increased in abundance. However, the RuBisCO large subunit and associated proteins were reduced, indicating a loss of carbon fixation but a continued need to supply the necessary carbon skeletons for the

  9. Effect of Permissive Dehydration on Induction and Decay of Heat Acclimation, and Temperate Exercise Performance

    PubMed Central

    Neal, Rebecca A.; Massey, Heather C.; Tipton, Michael J.; Young, John S.; Corbett, Jo

    2016-01-01

    Purpose: It has been suggested that dehydration is an independent stimulus for heat acclimation (HA), possibly through influencing fluid-regulation mechanisms and increasing plasma volume (PV) expansion. There is also some evidence that HA may be ergogenic in temperate conditions and that this may be linked to PV expansion. We investigated: (i) the influence of dehydration on the time-course of acquisition and decay of HA; (ii) whether dehydration augmented any ergogenic benefits in temperate conditions, particularly those related to PV expansion. Methods: Eight males [VO2max: 56.9(7.2) mL·kg−1·min−1] undertook two HA programmes (balanced cross-over design), once drinking to maintain euhydration (HAEu) and once with restricted fluid-intake (HADe). Days 1, 6, 11, and 18 were 60 min exercise-heat stress tests [HST (40°C; 50% RH)], days 2–5 and 7–10 were 90 min, isothermal-strain (Tre ~ 38.5°C), exercise-heat sessions. Performance parameters [VO2max, lactate threshold, efficiency, peak power output (PPO)] were determined pre and post HA by graded exercise test (22°C; 55%RH). Results: During isothermal-strain sessions hypohydration was achieved in HADe and euhydration maintained in HAEu [average body mass loss −2.71(0.82)% vs. −0.56(0.73)%, P < 0.001], but aldosterone concentration, power output, and cardiovascular strain were unaffected by dehydration. HA was evident on day 6 {reduced end-exercise Tre [−0.30(0.27)°C] and exercise heart rate [−12(15) beats.min−1], increased PV [+7.2(6.4)%] and sweat-loss [+0.25(0.22) L.h−1], P < 0.05} with some further adaptations on day 11 {further reduced end-exercise Tre [−0.25(0.19)°C] and exercise heart rate [−3(9) beats.min−1], P < 0.05}. These adaptations were not notably affected by dehydration and were generally maintained 7-days post HA. Performance parameters were unchanged, apart from increased PPO (+16(20) W, irrespective of condition). Conclusions: When thermal-strain is matched

  10. Dehydration and Symptoms of Delayed-Onset Muscle Soreness in Hyperthermic Males

    PubMed Central

    Cleary, Michelle A; Sweeney, Lori A; Kendrick, Zebulon V; Sitler, Michael R

    2005-01-01

    Context: Exercise in the heat produces cellular conditions that may leave skeletal muscle susceptible to exercise-induced microdamage. Delayed-onset muscle soreness (DOMS) is a clinical model of contraction-induced skeletal muscle injury. Objective: To determine whether thermoregulation during exercise heat stress adversely affects muscle injury and the accompanying DOMS. Design: Randomized group test-retest design. Setting: Laboratory. Patients or Other Participants: Ten healthy male volunteers were randomly assigned to either the euhydration/hyperthermic or dehydration/hyperthermic group. Intervention(s): Participants were randomly assigned to treadmill walking in a hot, humid environmental chamber (40°C and 75% relative humidity) with either oral rehydration (euhydration/hyperthermic) or fluid restriction (dehydration/hyperthermic). Immediately after heat exposure and while hyperthermic, participants performed an eccentrically biased downhill run to induce DOMS. Main Outcome Measure(s): We measured DOMS characteristics pre-exercise and at 0.5, 24, 48, 72, and 96 hours postexercise. Results: Treadmill exercise and exposure to the hot ambient environment elicited a 0.9% body mass loss for the euhydrated/ hyperthermic (mean rectal temperature after 60 minutes of heat-stress trial = 38.2 ± 0.4°C) and 3.3% body mass loss for the dehydrated/hyperthermic participants (mean rectal temperature after 60 minutes of heat-stress trial = 38.1 ± 0.4°C). Quadriceps perceived pain was significantly higher (F5,40 = 18.717, P ≤ .001) than baseline at 24 and 48 hours postexercise, following the classic pattern of DOMS. Overall lower extremity perceived pain was significantly higher for the dehydration/hyperthermia group than the euhydration/hyperthermia group (F1,8 = 6.713, P = .032). Punctate tenderness of the vastus lateralis for the dehydration/hyperthermic group was 6.9% higher (F5,40 = 4.462, P = .003) than for the euhydration/ hyperthermic group. No clinically

  11. The mechanism of dehydration in chromophore maturation of wild-type green fluorescent protein: A theoretical study

    NASA Astrophysics Data System (ADS)

    Ma, Yingying; Yu, Jian-Guo; Sun, Qiao; Li, Zhen; Smith, Sean C.

    2015-07-01

    An interesting aspect of the green fluorescent protein (GFP) is its autocatalytic chromophore maturation. Numerous experimental studies have indicated that dehydration is the last step in the chromophore maturation process of wild-type GFP. Based on the crystal structure of wild-type GFP, the mechanism of the reverse reaction of dehydration was investigated by using density functional theory (DFT) in this study. Our results proposed that the dehydration is exothermic. Moreover, the rate-limiting step of the mechanism is the proton on guanidinium of Arg96 transferring to the β-carbon anion of Tyr66, which is consistent with the experimental observation.

  12. Investigations of Factors to Improve Texture and Color of Freeze- Dehydrated and Subsequently Compressed Red Tart Pitted Cherries

    DTIC Science & Technology

    Freeze-dehydrated and compressed red tart pitted cherries , cultivar montmorency, were stored at 21C and 38 C for 12 to 6 months. Quality evaluations...better texture after rehydration. Red food color incorporation to the freeze dehydrated red tart pitted cherries improved the color; however, this was not successful on samples that had turned brown after storage at 38C....as storage time was increased. Sensory evaluations were made on dehydrated cherries prepared as pies. Sulfited cherries retained better color but the

  13. Recent advances in drying and dehydration of fruits and vegetables: a review.

    PubMed

    Sagar, V R; Suresh Kumar, P

    2010-01-01

    Fruits and vegetables are dried to enhance storage stability, minimize packaging requirement and reduce transport weight. Preservation of fruits and vegetables through drying based on sun and solar drying techniques which cause poor quality and product contamination. Energy consumption and quality of dried products are critical parameters in the selection of drying process. An optimum drying system for the preparation of quality dehydrated products is cost effective as it shortens the drying time and cause minimum damage to the product. To reduce the energy utilization and operational cost new dimensions came up in drying techniques. Among the technologies osmotic dehydration, vacuum drying, freeze drying, superheated steam drying, heat pump drying and spray drying have great scope for the production of quality dried products and powders.

  14. Use of aluminum phosphate as the dehydration catalyst in single step dimethyl ether process

    DOEpatents

    Peng, Xiang-Dong; Parris, Gene E.; Toseland, Bernard A.; Battavio, Paula J.

    1998-01-01

    The present invention pertains to a process for the coproduction of methanol and dimethyl ether (DME) directly from a synthesis gas in a single step (hereafter, the "single step DME process"). In this process, the synthesis gas comprising hydrogen and carbon oxides is contacted with a dual catalyst system comprising a physical mixture of a methanol synthesis catalyst and a methanol dehydration catalyst. The present invention is an improvement to this process for providing an active and stable catalyst system. The improvement comprises the use of an aluminum phosphate based catalyst as the methanol dehydration catalyst. Due to its moderate acidity, such a catalyst avoids the coke formation and catalyst interaction problems associated with the conventional dual catalyst systems taught for the single step DME process.

  15. Controlled fall in natremia and risk of seizures in hypertonic dehydration.

    PubMed

    Kahn, A; Brachet, E; Blum, D

    1979-03-01

    The aim of the study was to derive some practical measurements which might help in defining a "safe" infusion rate in order to avoid seizures during treatment of hypernatremic dehydration. Forty seven infants with hypernatremic dehydration were rehydrated on a 160 ml/kg/24 h basis: 9 developed seizures during treatment (group I), 22 matched for age did not convulse (group II). Nine subsequent cases were prescribed a 120 ml/kg/24 h regimen: none convulsed (group III). The three groups were comparable in many respects, including initial plasma Na and pH. Fluids were comparable regarding (Na), their rates of administration were respectively 216, 181 and 123 ml/kg/24 h. The rate of infusion affected slopes of decreases in natremia. It was suggested that the decrease in plasma Na should not exceed 0,5 mEq/1/h.

  16. From dehydration to hyperhidration isotonic and diuretic drinks and hyperhydratant aids in sport.

    PubMed

    Urdampilleta, Aritz; Gómez-Zorita, Saioa

    2014-01-01

    The needs of water and electrolytes are quite variants, depending on age, physiological or environmental conditions. In most long-term sports, usual weight loss of 3-6%, affect in athletic performance. The effects of a 6% dehydration could be improved with individualized diet-specific nutritional strategies and allow only a 2-3% dehydration, which affect metabolic efficiency but will not risk the health. On the contrary, hyperhydration can be dangerous and is associated with hyponatremia that can cause cerebral edema or respiratory failure. Sports drinks should moisturize, providing minerals and carbohydrates and increase the absorption of water by an ideal combination of salts and sugars. Therefore, it is important to provide correct hydration -protocols before, during and after physical activity, as well as know possible limitations of the sport.

  17. Effect of sucrose and binary solution on osmotic dehydration of bell pepper (chilli) (Capsicum spp.) varieties.

    PubMed

    Raji Abdul Ganiy, O; Falade Kolawole, O; Abimbolu Fadeke, W

    2010-06-01

    Pepper (chilli) (Capsicum annum) varieties, 'Tatase' and 'Rodo', (Capsicum frutescens) 'Sombo' and 'Bawa' were osmotically dehydrated in sucrose solutions of 40, 50 and 60o Brix and binary solutions of 50° sucrose with 5, 10 and 15% salt at 20, 30 and 40°C for 9 h. Samples osmosed at higher sugar concentrations (50° and 60°Brix) gave better results while improved solute gain were obtained using binary mixture with lower processing time, energy and cost. Effects of varietal differences on solid gain and water loss showed a descending in the order 'Sombo', 'Rodo', 'Bawa' and 'Tatase'. The colours were retained and stabilized after osmotic dehydration. Therefore, the solid gain and colour retention are indications of value addition.

  18. Effect of zeolite catalyst on sugar dehydration for 5-Hydroxymethylfurfural synthesis

    NASA Astrophysics Data System (ADS)

    Mostapha, Marhaini; Jahar, Noorhasmiera Abu; Chin, Siew Xian; Jaafar, Sharifah Nabihah Syed; Zakaria, Sarani; Aizat, Wan M.; Azizan, Kamalrul Azlan

    2016-11-01

    The effectiveness in the dehydration of sugars into 5-Hydroxymethylfurfural is related to the catalyst existence. A comprehensive synthesis of 5-Hydroxymethylfurfural from fructose, glucose and sucrose (3.73 mmol) with and without addition zeolite catalyst was performed in this study. The reactions were carried out in water-methanol solvent system for 3 hours reaction time at 180°C temperature. The catalytic results from HPLC showed that the reaction with zeolite increases the yield of 5-Hydroxymethylfurfural with 51.72 %, 34.01% and 50.10% for fructose, glucose and sucrose respectively. The study suggests that zeolites promote the isomerization of glucose into fructose to occur and simultaneously catalyze the dehydration of fructose into 5-Hydroxymethylfurfural. Only slight changes on FT-IR spectra of use zeolite after the reaction was observed. Thus suggest that zeolite was a potential catalyst for catalytic reaction for the conversion of sugar into 5-Hydroxymethylfurfural.

  19. [Acceleration of osmotic dehydration process through ohmic heating of foods: raspberries (Rubus idaeus)].

    PubMed

    Simpson, Ricardo R; Jiménez, Maite P; Carevic, Erica G; Grancelli, Romina M

    2007-06-01

    Raspberries (Rubus idaeus) were osmotically dehydrated by applying a conventional method under the supposition of a homogeneous solution, all in a 62% glucose solution at 50 degrees C. Raspberries (Rubus idaeus) were also osmotically dehydrated by using ohmic heating in a 57% glucose solution at a variable voltage (to maintain temperature between 40 and 50 degrees C) and an electric field intensity <100 V/cm. When comparing the results from both experiments it was evident that processing time is reduced when ohmic heating technique was used. In some cases this reduction reached even 50%. This is explained by the additional effect to the thermal damage that is generated in an ohmic process, denominated electroporation.

  20. Mechanism of Brønsted acid-catalyzed glucose dehydration.

    PubMed

    Yang, Liu; Tsilomelekis, George; Caratzoulas, Stavros; Vlachos, Dionisios G

    2015-04-24

    We present the first DFT-based microkinetic model for the Brønsted acid-catalyzed conversion of glucose to 5-hydroxylmethylfurfural (HMF), levulinic acid (LA), and formic acid (FA) and perform kinetic and isotopic tracing NMR spectroscopy mainly at low conversions. We reveal that glucose dehydrates through a cyclic path. Our modeling results are in excellent agreement with kinetic data and indicate that the rate-limiting step is the first dehydration of protonated glucose and that the majority of glucose is consumed through the HMF intermediate. We introduce a combination of 1) automatic mechanism generation with isotopic tracing experiments and 2) elementary reaction flux analysis of important paths with NMR spectroscopy and kinetic experiments to assess mechanisms. We find that the excess formic acid, which appears at high temperatures and glucose conversions, originates from retro-aldol chemistry that involves the C6 carbon atom of glucose.

  1. Optimization of hydrous ferrous sulfate dehydration by microwave heating using response surface methodology.

    PubMed

    Yu, Yan-Tao; Liu, Bing-Guo; Chen, Guo; Peng, Jin-Hui; Srinivasakannan, C

    2012-01-01

    The work relates to assessing the ability of the microwave for dehydration of large amount of waste hydrous ferrous sulfate generated from the titanium pigment process industry. The popular process optimization tool of response surface methodology with central composite design was adopted to estimate the effect of dehydration. The process variables were chosen to be power input, duration of heating and the bed thickness, while the response variable being the weight loss. An increase in all the three process variables were found to significantly increase the weight loss, while the effect of interaction among the parameters were found to be insignificant. The optimized process conditions that contribute to the maximum weight loss were identified to be a power input of 960 W, duration of heating of 14 min and bed thickness of 5 cm, resulting in a weight loss of 31.44%. The validity of the optimization process was tested with the repeat runs at optimized conditions.

  2. Effect of Temperature, Time, and Material Thickness on the Dehydration Process of Tomato

    PubMed Central

    Correia, A. F. K.; Loro, A. C.; Zanatta, S.; Spoto, M. H. F.; Vieira, T. M. F. S.

    2015-01-01

    This study aimed to evaluate the effects of temperature, time, and thickness of tomatoes fruits during adiabatic drying process. Dehydration, a simple and inexpensive process compared to other conservation methods, is widely used in the food industry in order to ensure a long shelf life for the product due to the low water activity. This study aimed to obtain the best processing conditions to avoid losses and keep product quality. Factorial design and surface response methodology were applied to fit predictive mathematical models. In the dehydration of tomatoes through the adiabatic process, temperature, time, and sample thickness, which greatly contribute to the physicochemical and sensory characteristics of the final product, were evaluated. The optimum drying conditions were 60°C with the lowest thickness level and shorter time. PMID:26904666

  3. Dehydration polycondensation of dicarboxylic acids and diols using sublimating strong brønsted acids.

    PubMed

    Moyori, Takaya; Tang, Tang; Takasu, Akinori

    2012-05-14

    We investigated catalytic activities of strong brønsted acids for dehydration polycondensations of dicarboxylic acids and diols, which were carried out at low temperature (<100 °C) under reduced pressure (0.3-3 mmHg). Strong Brønsted acids, bis(perfluoroalkanesulfonyl)imide and perfluoroalkanesulfonic acid, showed higher activity than p-toluenesulfonic acid or rare-earth catalysts at 60 °C. In particular, bis(nonafluorobutanesulfonyl)imide (Nf(2)NH) showed the highest activity to synthesize not only aliphatic polyester (M(n) > 19000) but also aromatic polyester (M(n) > 7000). The used Nf(2)NH was sublimated from the reaction flask during polycondensation, and the sublimate, Nf(2)NH, was extra pure so that we can reuse the catalyst without loss of the activity in the dehydration polycondensations.

  4. Dehydration, hemodynamics and fluid volume optimization after induction of general anesthesia

    PubMed Central

    Li, Yuhong; He, Rui; Ying, Xiaojiang; Hahn, Robert G

    2014-01-01

    OBJECTIVES: Fluid volume optimization guided by stroke volume measurements reduces complications of colorectal and high-risk surgeries. We studied whether dehydration or a strong hemodynamic response to general anesthesia increases the probability of fluid responsiveness before surgery begins. METHODS: Cardiac output, stroke volume, central venous pressure and arterial pressures were measured in 111 patients before general anesthesia (baseline), after induction and stepwise after three bolus infusions of 3 ml/kg of 6% hydroxyethyl starch 130/0.4 (n = 86) or Ringer's lactate (n = 25). A subgroup of 30 patients who received starch were preloaded with 500 ml of Ringer's lactate. Blood volume changes were estimated from the hemoglobin concentration and dehydration was estimated from evidence of renal water conservation in urine samples. RESULTS: Induction of anesthesia decreased the stroke volume to 62% of baseline (mean); administration of fluids restored this value to 84% (starch) and 68% (Ringer's). The optimized stroke volume index was clustered around 35-40 ml/m2/beat. Additional fluid boluses increased the stroke volume by ≥10% (a sign of fluid responsiveness) in patients with dehydration, as suggested by a low cardiac index and central venous pressure at baseline and by high urinary osmolality, creatinine concentration and specific gravity. Preloading and the hemodynamic response to induction did not correlate with fluid responsiveness. The blood volume expanded 2.3 (starch) and 1.8 (Ringer's) times over the infused volume. CONCLUSIONS: Fluid volume optimization did not induce a hyperkinetic state but ameliorated the decrease in stroke volume caused by anesthesia. Dehydration, but not the hemodynamic response to the induction, was correlated with fluid responsiveness. PMID:25627992

  5. Specimen size effect in the volumetric shrinkage of cancellous bone measured at two levels of dehydration.

    PubMed

    Lievers, W Brent; Lee, Victoria; Arsenault, Simon M; Waldman, Stephen D; Pilkey, A Keith

    2007-01-01

    Water is commonly removed from bone to study its effect on mechanical behaviour; however, dehydration also alters the bone structure. To make matters worse, measuring structural changes in cancellous bone is complicated by a number of factors. Therefore, the goals of this study were to address these issues by (1) comparing Archimedes' method and a helium pycnometer as methods for measuring cancellous bone volume; (2) measuring the apparent dimensional and volumetric tissue shrinkage of cancellous bone at two levels of dehydration; and, (3) identifying whether a size effect exists in cancellous bone shrinkage. Cylindrical specimens (3, 5 and 8.3 mm diameters) of cancellous bone were taken from the distal bovine femur. The apparent dimensions of each cylindrical specimen were measured in a fully hydrated state (HYD), after drying at room temperature (AIR), and after oven drying at 105 degrees C (OVEN). Tissue volume measurements for those three hydration states were obtained using both a helium pycnometer and Archimedes' method. Aluminium foams, which mimic the cancellous structure, were used as controls. The results suggest that the helium pycnometer and Archimedes' method yield identical results in the HYD and AIR states, but that Archimedes' method under-predicts the nominal OVEN volume by incorporating the collagen-apatite porosity. A distinct size effect on volumetric shrinkage is observed (p<0.025) using the pycnometer in both AIR and OVEN states. Apparent dimensional shrinkage (2% and 7%) at the two dehydration levels is much smaller than the measured volumetric tissue shrinkage (16% and 29%), which results in a reduced dehydrated bone volume fraction.

  6. Membrane permeation process for dehydration of organic liquid mixtures using sulfonated ion-exchange polyalkene membranes

    DOEpatents

    Cabasso, Israel; Korngold, Emmanuel

    1988-01-01

    A membrane permeation process for dehydrating a mixture of organic liquids, such as alcohols or close boiling, heat sensitive mixtures. The process comprises causing a component of the mixture to selectively sorb into one side of sulfonated ion-exchange polyalkene (e.g., polyethylene) membranes and selectively diffuse or flow therethrough, and then desorbing the component into a gas or liquid phase on the other side of the membranes.

  7. Effects of catalyst pore structure and acid properties on the dehydration of glycerol.

    PubMed

    Choi, Youngbo; Park, Hongseok; Yun, Yang Sik; Yi, Jongheop

    2015-03-01

    Hierarchical porous catalysts have recently attracted increasing interest because of the enhanced accessibility to active sites on such materials. In this context, previously reported hierarchically mesoporous ASN and ASPN materials are evaluated by applying them to the dehydration of glycerol, and demonstrate excellent catalytic performance. In addition, a comprehensive understanding of the effects of pore structures and the acid properties on the reaction through comparative studies with microporous HZSM-5 and mesoporous AlMCM-41 is provided.

  8. Controlled fall in natremia in hypertonic dehydration: possible avoidance of rehydration seizures.

    PubMed

    Kahn, A; Blum, D; Casimir, G; Brachet, E

    1981-02-01

    This prospective study comprises 40 infants with severe hypernatremic dehydration due to gastroenteritis. During the first 24h, natremia was closely monitored and infusion rates were adjusted so as to keep the rate of fall in natremia below 0.5 mEq/l/h. This could be achieved by giving a 70 mEq/l Na solution at the rate of 120 ml/kg/24 h. Rehydration was uneventful in all cases, and no convulsions were observed.

  9. [Aortic and cerebral trombosis caused by hypernatremic dehydration in an exclusively breast-fed infant].

    PubMed

    Iglesias Fernández, C; Chimenti Camacho, P; Vázquez López, P; Guerrero Soler, M; Blanco Bravo, D

    2006-10-01

    Complete aortic thrombosis is rare in neonates. Because it carries high morbidity and mortality, this entity requires aggressive and early treatment. This report describes an 8-day-old healthy and exclusively breast-fed infant, without specific coagulopathy, who developed complete aortic and cerebral venous thrombosis, which was attributed to inadequate breast-feeding and severe hypernatremic dehydration. Early systemic anticoagulation and thrombolytic therapy allowed complete resolution of the problem.

  10. Lewis acid catalyzed cascade reaction to carbazoles and naphthalenes via dehydrative [3 + 3]-annulation.

    PubMed

    Wang, Shaoyin; Chai, Zhuo; Wei, Yun; Zhu, Xiancui; Zhou, Shuangliu; Wang, Shaowu

    2014-07-03

    A novel Lewis acid catalyzed dehydrative [3 + 3]-annulation of readily available benzylic alcohols and propargylic alcohols was developed to give polysubstituted carbazoles and naphthalenes in moderate to good yields with water as the only byproduct. The reaction was presumed to proceed via a cascade process involving Friedel-Crafts-type allenylation, 1,5-hydride shift, 6π-eletrocyclization, and Wagner-Meerwein rearrangement.

  11. Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

    PubMed Central

    Huang, Guozheng; Schramm, Simon; Heilmann, Jörg; Biedermann, David; Křen, Vladimír

    2016-01-01

    Summary Various Mitsunobu conditions were investigated for a series of flavonolignans (silybin A, silybin B, isosilybin A, and silychristin A) to achieve either selective esterification in position C-23 or dehydration in a one-pot reaction yielding the biologically important enantiomers of hydnocarpin D, hydnocarpin and isohydnocarpin, respectively. This represents the only one-pot semi-synthetic method to access these flavonolignans in high yields. PMID:27340458

  12. Fracture toughness and work of fracture of hydrated, dehydrated, and ashed bovine bone.

    PubMed

    Yan, Jiahau; Daga, Amit; Kumar, Rajendra; Mecholsky, John J

    2008-01-01

    Bone, a tri-phase composite, consists of nano-sized apatite minerals, an organic component, and water. Heat-treated bovine cortical bone has been proposed as a candidate for void-filling bone substitute. However, the toughness of heat-treated bone is not yet fully studied. Fracture toughness (K(c)) and work of fracture (W(f)) of hydrated, dehydrated, and ashed bovine bone were estimated using a single-edge V-notched beam method. Thermal gravimetric analysis and differential thermal analysis were used to determine the temperature at which the organics and water were removed. Dehydrated specimens were obtained by placing the samples in a 60 degrees C vacuum oven for 24h or a 110 degrees C furnace for 2h. Ashed specimens were obtained by heat-treating samples at 600 degrees C for 24h. K(c) of bovine specimens decreased from 5.5MPa.m(1/2) for hydrated bone, to 3.8MPa.m(1/2) for dehydrated specimens, and to 0.36MPa.m(1/2) for ashed specimens. W(f) decreased from 7.1 to 1.1kJ/m(2) for dehydrated specimens, and to 0.04kJ/m(2) for ashed specimens. The main reasons for the significant decreases in K(c) and W(f) may be attributed to water's ability in stabilizing collagen structure and to the organics' ability in making bone more ductile. Because of the large decrease in fracture toughness and work of fracture, we suggest that ashed bone is not appropriate for load-bearing bone substitute in areas where bone experiences loadings in flexure.

  13. Sex-specific divergence for adaptations to dehydration stress in Drosophila kikkawai.

    PubMed

    Parkash, Ravi; Ranga, Poonam

    2013-09-01

    Several studies on diverse Drosophila species have reported higher desiccation resistance of females, but the physiological basis of such sex-specific differences has received less attention. We tested whether sex-specific differences in cuticular traits (melanic females and non-melanic males) of Drosophila kikkawai correspond with divergence in their water balance mechanisms. Our results are interesting in several respects. First, positive clinal variation in desiccation resistance was correlated with cuticular melanisation in females but with changes in cuticular lipid mass in males, despite a lack of differences between the sexes for the rate of water loss. Second, a comparative analysis of water budget showed that females of the northern population stored more body water as well as hemolymph content and exhibited greater dehydration tolerance than flies from the southern tropics. In contrast, we found no geographical variation in the males for water content and dehydration tolerance. Third, an ~10-fold increase in the rate of water loss after organic solvent treatment of male D. kikkawai suggested a role of cuticular lipids in cuticular transpiration, but had no effect in the females. Fourth, geographical differences in the storage of carbohydrate content (metabolic fuel) were observed in females but not in males. Interestingly, in females, the rate of utilization of carbohydrates did not vary geographically, but males from drier localities showed a 50% reduction compared with wetter localities. Thus, body melanisation, increased body water, hemolymph, carbohydrate content and greater dehydration tolerance confer greater desiccation resistance in females, but a reduced rate of water loss is the only possible mechanism to cope with drought stress in males. Finally, acclimated females showed a significant increase in drought resistance associated with higher trehalose content as well as dehydration tolerance, while males showed no acclimation response. Thus, sex

  14. Alcohol pharmacokinetics and risk-taking behaviour following exercise-induced dehydration.

    PubMed

    Irwin, Christopher; Goodwin, Alison; Leveritt, Michael; Davey, Andrew K; Desbrow, Ben

    2012-06-01

    This study investigated the influence of exercise-induced dehydration on alcohol pharmacokinetics, subjective ratings of impairment, and risk-taking behaviours. Twelve male volunteers participated in 3 experimental trials completed in a randomised cross over design separated by at least 7 days. In one trial, participants exercised to cause dehydration of ~2.5% body weight loss. For the other trials, participants were required to be in a rested and euhydrated state. A set volume of alcohol was then consumed in each trial and participants were monitored over a 4h period. Blood (BAC) and breath (BrAC) alcohol samples were collected throughout and analysed to calculate pharmacokinetic variables associated with the blood alcohol curve. Total urine production, estimates of BrAC, and subjective ratings of intoxication and impairment were also recorded throughout each trial. No difference was found in the pharmacokinetics of alcohol between any of the trial conditions. BrACs were higher than BACs for 2h following alcohol consumption, but lower at measures taken 3 and 4 h post ingestion. Participants' ratings of confusion and intoxication were significantly lower, and they were more willing to drive in the dehydration trial compared with one of the euhydration trials. These findings suggest that dehydration or other physiological changes associated with exercise may have an ability to influence the subjective effects of alcohol and increase the likelihood of risk-taking behaviours such as drink-driving. However, further research is required to examine the effects of alcohol under conditions of exercise-induced fluid loss in order to clarify these findings.

  15. Evidence Based Weighing Policy during the First Week to Prevent Neonatal Hypernatremic Dehydration while Breastfeeding

    PubMed Central

    Boer, Suzanne; Unal, Sevim; van Dommelen, Paula

    2016-01-01

    Background Neonatal hypernatremic dehydration is prevented by daily neonatal weight monitoring. We aim to provide evidence-based support of this universally promoted weighing policy and to establish the most crucial days of weighing. Methods Weight measurements of 2,359 healthy newborns and of 271 newborns with clinical hypernatremic dehydration were used within the first seven days of life to simulate various weighting policies to prevent hypernatremic dehydration; its sensitivity, specificity and positive predictive value (PPV) of these policies were calculated. Various referral criteria were also evaluated. Results A policy of daily weighing with a cut-off value of -2.5 Standard Deviation Score (SDS) on the growth chart for weight loss, had a 97.6% sensitivity, 97.6% specificity and a PPV of 2.80%. Weighing at birth and only at days two, four and seven with the same -2.5 SDS cut-off, resulted in 97.3% sensitivity, 98.5% specificity and a PPV of 4.43%. Conclusion A weighing policy with measurements restricted to birth and day two, four and seven applying the -2.5 SDS cut-off seems an optimal policy to detect hypernatremic dehydration. Therefore we recommend to preferably weigh newborns at least on day two (i.e. ~48h), four and seven, and refer them to clinical pediatric care if their weight loss increases below -2.5 SDS. We also suggest lactation support for the mother, full clinical assessment of the infant and weighing again the following day in all newborns reaching a weight loss below -2.0 SDS. PMID:27997557

  16. Identification of a novel dehydration responsive gene, drp10, from the African clawed frog, Xenopus laevis.

    PubMed

    Biggar, Kyle K; Biggar, Yulia; Storey, Kenneth B

    2015-07-01

    During periods of environmental stress a number of different anuran species employ adaptive strategies to promote survival. Our study found that in response to dehydration (i.e., loss of total body water content), the African clawed frog (Xenopus laevis) increased the expression of a novel gene (drp10) that encodes a structural homolog of the freeze-responsive FR10 protein found in wood frogs. Similar to FR10, the DRP10 protein was found to also contain a highly conserved N-terminal cleavable signal peptide. Furthermore, DRP10 was found to have high structural homology to the available crystal structures of type A and E apolipoproteins in Homo sapiens, and a type IV LS-12 anti-freeze protein in the longhorn sculpin, Myoxocephalus octodecemspinosis. In response to dehydration, the transcript expression of drp10 was found to increase 1.52 ± 0.16-fold and 1.97 ± 0.11-fold in response to medium (15%) and high (30%) dehydration stresses in the liver tissue of X. laevis, respectively, while drp10 expression increased 2.12 ± 0.12-fold and 1.46 ± 0.16-fold in kidney tissue. Although the molecular function of both dehydration-responsive DRP10 and the freeze-responsive FR10 have just begun to be elucidated, it is likely that both are frog-specific proteins that likely share a similar purpose during water-related stresses.

  17. Subquality natural gas sweetening and dehydration potential of the physical solvent N-formyl-morpholine

    SciTech Connect

    Semrau, J.T.; Palla, N.; Lee, A.L.

    1995-03-01

    Almost all gas produced in the United States requires processing before it is placed in the transmission system. For approximately 50% of the gas, this is just dehydration. The remainder, however, requires processing that is more complex and costly. A report to the Gas Research Institute states that about 30% of the proven gas reserves contained sufficient nitrogen, carbon dioxide or hydrogen sulfide to be classified as a subquality.

  18. Adaptive plasticity of killifish (Fundulus heteroclitus) embryos: dehydration-stimulated development and differential aquaporin-3 expression.

    PubMed

    Tingaud-Sequeira, Angèle; Zapater, Cinta; Chauvigné, François; Otero, David; Cerdà, Joan

    2009-04-01

    Embryos of the marine killifish Fundulus heteroclitus are adapted to survive aerially. However, it is unknown if they are able to control development under dehydration conditions. Here, we show that air-exposed blastula embryos under saturated relative humidity were able to stimulate development, and hence the time of hatching was advanced with respect to embryos continuously immersed in seawater. Embryos exposed to air at later developmental stages did not hatch until water was added, while development was not arrested. Air-exposed embryos avoided dehydration probably because of their thickened egg envelope, although it suffered significant evaporative water loss. The potential role of aquaporins as part of the embryo response to dehydration was investigated by cloning the aquaporin-0 (FhAqp0), -1a (FhAqp1a), and -3 (FhAqp3) cDNAs. Functional expression in Xenopus laevis oocytes showed that FhaAqp1a was a water-selective channel, whereas FhAqp3 was permeable to water, glycerol, and urea. Expression of fhaqp0 and fhaqp1a was prominent during organogenesis, and their mRNA levels were similar between water- and air-incubated embryos. However, fhaqp3 transcripts were highly and transiently accumulated during gastrulation, and the protein product was localized in the basolateral membrane of the enveloping epithelial cell layer and in the membrane of ingressing and migrating blastomers. Interestingly, both fhaqp3 transcripts and FhAqp3 polypeptides were downregulated in air-exposed embryos. These data demonstrate that killifish embryos respond adaptively to environmental desiccation by accelerating development and that embryos are able to transduce dehydration conditions into molecular responses. The reduced synthesis of FhAqp3 may be one of these mechanisms to regulate water and/or solute transport in the embryo.

  19. Compression of fractionated sun-cured and dehydrated alfalfa chops into cubes--specific energy models.

    PubMed

    Adapa, Phani; Schoenau, Greg; Tabil, Lope; Sokhansanj, Shahab; Singh, Asheesh

    2007-01-01

    The objective of this study was to determine the specific energy requirements for the compression of fractionated sun-cured and dehydrated alfalfa chops, when subjected to different pressures and holding times. The compression behavior of fractionated sun-cured and dehydrated alfalfa chops was studied using a single cubing unit capable of making one cube in a single stroke of the plunger. The cube die dimensions were 30 mm x 30 mm in cross-section and an effective depth of compression of 0.38 m. The initial moisture content of dehydrated and sun-cured chops were 6% and 7% (wb), respectively. A stack of two sieves (instead of five) was used along with a pan to achieve leaf and stem separation. The nominal opening sizes of two sieves with square holes were 3.96 and 1.17 mm, respectively. Leaf and stem fractions were combined later to obtain five different samples each for sun-cured and dehydrated alfalfa with leaf content ranging from 0% to 100% by mass in increments of 25%. The chop moisture content and preheat temperature before compaction was 10% (wb) and 75 degrees C, respectively. The cube die temperature was maintained at 90+/-5 degrees C. The mass of chops used for making each cube was 23+/-02 g. A hydraulic press was used to apply 9.0, 12.0 and 14.0 MPa of pressures through a plunger. After compression, the plunger was held in place for 10 and 30s, before the compacted forage was extracted. Empirical equations were fitted to the data relating specific energy for cube making to pressure, residence time, and leaf content.

  20. Dielectric relaxation spectroscopy of hydrated and dehydrated silk fibroin cast from aqueous solution.

    PubMed

    Yu, Lei; Hu, Xiao; Kaplan, David; Cebe, Peggy

    2010-10-11

    The dynamics of silk protein in the presence and absence of water has been investigated by dielectric relaxation spectroscopy (DRS). The silk fibroin film cast from its water solution contains 4-7 wt % bound water molecules, which can be removed by dehydration at 165 °C. Temperature and frequency scans were performed on the hydrated and dehydrated samples over the temperature range from -100 to 280 °C, and frequency range from 20 to 1 MHz. Temperature scans of hydrated samples show three relaxation peaks, including β- and α-relaxations, related to bound water and to the glass transition. A new third peak, denoted as α', was seen in hydrated sample at around 60 °C, and its intensity increases with decreasing frequency. On the other hand, in the completely dehydrated sample, the β- and α'-relaxation peaks both disappeared, which reveals their origin from bound water molecules. The α' process is attributed to the removal of bound water, after which the glass transition of dehydrated silk appears at higher temperature as the α process. Real-time DRS has also been performed to monitor isothermal crystallization. Both the dielectric constant, ε', and conductivity, σ, decrease gradually as the crystallization proceeds. Analysis of dielectric modulus shows that both conductivity and the α-relaxation are observed at the beginning of crystallization. As the crystal grows, the α-relaxation starts gradually to diminish both in strength and in rate. Before crystallization, α-helices and random coils with dipole moments are the major components in silk fibroin. During crystallization, α-helices can be transformed into antiparallel β-sheets, which possess no dipole moment, causing the decreasing trend in the dielectric parameters as crystallization proceeds.

  1. Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges

    PubMed Central

    Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

    2016-01-01

    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. PMID:27386526

  2. Dehydration as a Cause of Chronic Kidney Disease: Role of Fructokinase

    DTIC Science & Technology

    2015-10-01

    of islet cell fructokinase in the development of diabetes . The liver fructokinase can also be targeted and may be responsible for the fatty liver and...Meetings (April 2016), and the Central American coalition on Mesoamerican Nephropathy (November 2015). These lectures provide an avenue for...approaches to the treatment of dehydration. What was the impact on society beyond science and technology? Our studies could lead to a reevaluation of

  3. Implementation of a microfluidic conductivity sensor -- a potential sweat electrolyte sensing system for dehydration detection.

    PubMed

    Gengchen Liu; Smith, Kyle; Kaya, Tolga

    2014-01-01

    As dehydration continues to plague performance athletes and soldiers, the need for improved dehydration detection is clear. We propose the use of a conductometric sensor as the foundation of a sweat-sensing patch to address this need. The conductometric sensor evaluates the conductivity of solutions with varying sodium concentrations. A lithographic process was used to fabricate a Polydimethylsiloxane (PDMS) microfluidic channel through which solution was flowed. The ionization of the solution that occurs when a voltage is applied results in an effective resistance across the channel. The measured resistance therefore, reflects the ionization of the solution and the corresponding sodium concentration. The potential application of the conductometric sensor in a sweat-sensing patch requires compatibility with a microcontroller and Bluetooth module. Thus, a circuit interface was created. A voltage divider was utilized to convert the output resistance of the sensor to a voltage that could be input into a microcontroller. An AC voltage signal with a frequency of 10 kHz was used as the source voltage of the voltage divider to minimize the faradaic impedance and the double layer effect of the ionized solution. Tests have revealed that the conductometric is capable of precisely measuring the conductivity of a sodium solution. The conductometric sensor will be applied to a sweat sensing patch through future work involving studying the link between sodium concentration in sweat and an individual's dehydration level, developing a sweat-collection method, and developing a method of consideration for the other ions contained in sweat.

  4. Ingestive Behavior of Ovine Fed with Marandu Grass Silage Added with Naturally Dehydrated Brewery Residue

    PubMed Central

    Lima de Souza, Alexandre; Divino Ribeiro, Marinaldo; Mattos Negrão, Fagton; Castro, Wanderson José Rodrigues; Valério Geron, Luiz Juliano; de Azevedo Câmara, Larissa Rodrigues

    2016-01-01

    The objective was to evaluate the ingestive behavior of ovine fed Marandu grass silage with dehydrated brewery residue added. The experiment had a completely randomized design with five treatments and four repetitions, with the treatments levels of inclusion being of 0, 10, 20, 30, and 40% natural matter of naturally dehydrated brewery residue for 36 hours to the marandu grass silage. 20 ovines were used and the experimental period was 21 days, 15 being for adaptation to diets. The use of brewery byproduct promoted quadratic effect (P < 0.05) for the consumption of dry matter with maximum point value estimated at adding 23.25% additive. Ingestion efficiency and rumination efficiency of dry matter (g DM/hour) were significant (P < 0.05), by quadratic behavior, and NDF ingestion and rumination efficiency showed crescent linear behavior. The DM and NDF consumption expressed in kg/meal and in minutes/kg were also significant (P < 0.05), showing quadratic behavior. Rumination activity expressed in g DM and NDF/piece was influenced (P < 0.05) by the adding of brewery residue in marandu grass silage in quadratic way, with maximum value estimated of 1.57 g DM/bolus chewed in inclusion of 24.72% additive in grass silage. The conclusion is that intermediary levels adding of 20 to 25% dehydrated brewery residue affects certain parameters of ingestive behavior. PMID:27547811

  5. [Nutritional evaluation of green plantain flour dehydrated soups. Starch in vitro digestibility].

    PubMed

    Pacheco de Delahaye, E

    2001-01-01

    Previous works have shown that green plantain flour (GPF) contains a considerable amount of resistant with similar effects to dietary fiber. In order to diversify the use of this fruit the purpose of present study was to formulate and elaborate powered, dehydrated, cream type soups with green plantain flour flavored with vegetables (onion, coriander and leak) which increase the dietary fiber content of the preparation. Green plantain was peeled, cut in medium size pieces and submerged in 0.1% citric acid solution. The dehydration process was forced air-drying (80 degrees C), followed by milling. The same procedure was applied to the flavoring vegetables. To obtain the cream type soups various formulations were tried containing 50-63% resistant starch, 11.7-12% dietary fiber 6.5-6.9% protein. The mineral content of the preparations is reported. Viscosity of 1:10 (w/v) soups was 630-670 cps. In vitro starch digestibility after 6 hours was 38% with porcine amylase, increasing to 48% if the enzyme was from bacterial origin, supporting previous results that suggest resistance to hydrolysis of green plantain (GP) starch granules. In conclusion this study diversifies the use of GP and suggests that dehydrated GPF soups due to their high dietary fiber, resistant starch content and to the slow starch hydrolysis may be used in special nutrition regimes.

  6. Effects of cold and hot temperature on dehydration: a mechanism of cardiovascular burden.

    PubMed

    Lim, Youn-Hee; Park, Min-Seon; Kim, Yoonhee; Kim, Ho; Hong, Yun-Chul

    2015-08-01

    The association between temperature (cold or heat) and cardiovascular mortality has been well documented. However, few studies have investigated the underlying mechanism of the cold or heat effect. The main goal of this study was to examine the effect of temperature on dehydration markers and to explain the pathophysiological disturbances caused by changes of temperature. We investigated the relationship between outdoor temperature and dehydration markers (blood urea nitrogen (BUN)/creatinine ratio, urine specific gravity, plasma tonicity and haematocrit) in 43,549 adults from Seoul, South Korea, during 1995-2008. We used piece-wise linear regression to find the flexion point of apparent temperature and estimate the effects below or above the apparent temperature. Levels of dehydration markers decreased linearly with an increase in the apparent temperature until a point between 22 and 27 °C, which was regarded as the flexion point of apparent temperature, and then increased with apparent temperature. Because the associations between temperature and cardiovascular mortality are known to be U-shaped, our findings suggest that temperature-related changes in hydration status underlie the increased cardiovascular mortality and morbidity during high- or low-temperature conditions.

  7. Enhancement of mass transfer by ultrasound: Application to adsorbent regeneration and food drying/dehydration.

    PubMed

    Yao, Ye

    2016-07-01

    The physical mechanisms of heat and mass transfer enhancement by ultrasound have been identified by people. Basically, the effect of 'cavitation' induced by ultrasound is the main reason for the enhancement of heat and mass transfer in a liquid environment, and the acoustic streaming and vibration are the main reasons for that in a gaseous environment. The adsorbent regeneration and food drying/dehydration are typical heat and mass transfer process, and the intensification of the two processes by ultrasound is of complete feasibility. This paper makes an overview on recent studies regarding applications of power ultrasound to adsorbent regeneration and food drying/dehydration. The concerned adsorbents include desiccant materials (typically like silica gel) for air dehumidification and other ones (typically active carbon and polymeric resin) for water treatment. The applications of ultrasound in the regeneration of these adsorbents have been proved to be energy saving. The concerned foods are mostly fruits and vegetables. Although the ultrasonic treatment may cause food degradation or nutrient loss, it can greatly reduce the food processing time and decrease drying temperature. From the literature, it can be seen that the ultrasonic conditions (i.e., acoustic frequency and power levels) are always focused on during the study of ultrasonic applications. The increasing number of relevant studies argues that ultrasound is a very promising technology applied to the adsorbent regeneration and food drying/dehydration.

  8. Dehydration, skeletal muscle damage and inflammation before the competitions among the elite wrestlers

    PubMed Central

    Ozkan, Isik; Ibrahim, Cicioglu H.

    2016-01-01

    [Purpose] The present study aimed to identify weight-loss and hydration levels before competitions among elite wrestlers and determine the skeletal muscle damage and inflammation levels after dehydration. [Subjects] Seventy-two elite wrestlers who participated in the Turkish Wrestling Championship. [Methods] With the help of specialists, 5 cc of blood were drawn from the forearm veins of the wrestlers. Laboratory analyses of Na+, BUN, Glucose, CK, LDH, AST, ALT, C-RP levels were performed. Using a mathematical formula for hydration the POsm levels of the athletes were calculated. [Results] The wrestlers were divided into two groups based on hydration status. There were significant correlations between hydration indicators of Na+, BUN and PBWL values. There were significant differences between AST, LDH, CK values and skeletal muscle damage indicators of the two groups, but there were no significant differences between the inflammation levels and C-RP values of the groups. [Conclusion] No differences existed in inflammation levels among the wrestlers, although dehydrated wrestlers suffered from higher level of skeletal muscle damage than wrestlers who were not dehydrated. PMID:26957750

  9. Thermal dehydration of magnesium acetate tetrahydrate: formation and in situ crystallization of anhydrous glass.

    PubMed

    Koga, Nobuyoshi; Suzuki, Yasumichi; Tatsuoka, Tomoyuki

    2012-12-13

    The kinetics and mechanism of the thermal dehydration of magnesium acetate tetrahydrate were investigated as a typical example of the glass formation process via the thermal decomposition of solids. Formation of an intermediate fluid phase was identified as the characteristic phenomenon responsible for the formation of anhydrous glass. Thermal dehydration from the surface fluid layer regulates the zero-order-like rate behavior of the mass-loss process with an apparent activation energy E(a) ≈ 70-80 kJ mol(-1). Because of variations in the mechanism of release of the water vapor with changes in the reaction temperature range, the mass-loss behavior is largely dependent on the particle size of the sample and heating conditions. The formation of hollow anhydrous glass is the novel finding of the present study. The mechanism of formation is discussed in terms of complementary interpretations of the morphological changes and kinetic behavior of the thermal dehydration. On further heating, the as-produced anhydrous glass exhibits a glass transition phenomenon at approximately 470 K with an E(a) ≈ 550-560 kJ mol(-1), and subsequently crystallizes via the three-dimensional growth of nuclei controlled by diffusion. The crystallization process is characterized by an E(a) ≈ 280 kJ mol(-1) and an enthalpy change ΔH = -13.3 kJ mol(-1), resulting in the formation of smaller, rounded particles of crystalline anhydrate.

  10. Protection of dehydrated chicken meat by natural antioxidants as evaluated by electron spin resonance spectrometry.

    PubMed

    Nissen, L R; Månsson, L; Bertelsen, G; Huynh-Ba, T; Skibsted, L H

    2000-11-01

    Dehydrated chicken meat (a(w) = 0.20-0.35) made from mechanically deboned chicken necks can be protected against oxidative deterioration during storage by rosemary extract (at a sensory acceptable level of 1000 ppm, incorporated prior to drying). The efficiency of the rosemary extract was similar to that obtained by synthetic antioxidants in a reference product (70 ppm butylated hydroxyanisole and 70 ppm octyl gallate). Tea extract and coffee extract were less efficient than rosemary and synthetic antioxidants. Among the natural antioxidants tested, grape skin extract provided the least protection against oxidative changes in dehydrated chicken meat. Radicals in the product, quantified by direct measurement by electron spin resonance (ESR) spectrometry, developed similarly to headspace ethane, pentane, and hexanal, and to oxygen depletion both in unprotected and protected products. The ESR signal intensity and headspace hexanal both correlated with the sensory descriptor "rancidity" as evaluated by a trained sensory panel. Hexanal, as a secondary lipid oxidation product, showed an exponential dependence on the level of radicals in the product in agreement with a chain reaction mechanism for autoxidation, and direct ESR measurement may be used in quality control of dehydrated food products.

  11. Dehydration of fructose to 5-hydroxymethylfurfural by rare earth metal trifluoromethanesulfonates in organic solvents.

    PubMed

    Wang, Fenfen; Shi, Ai-Wu; Qin, Xiao-Xia; Liu, Chun-Ling; Dong, Wen-Sheng

    2011-05-15

    The catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) was investigated by using various rare earth metal trifluoromethanesulfonates, that is, Yb(OTf)(3), Sc(OTf)(3), Ho(OTf)(3), Sm(OTf)(3), Nd(OTf)(3) as catalysts in DMSO. It is found that the catalytic activity increases with decreasing ionic radius of rare earth metal cations. Among the examined catalysts, Sc(OTf)(3) exhibits the highest catalytic activity. Fructose conversion of 100% and a HMF yield of 83.3% are obtained at 120°C after 2h by using Sc(OTf)(3) as the catalyst. Moreover, the catalytic dehydration of fructose was also carried out in different solvents, for example, DMA, 1,4-dioxane, and a mixture of PEG-400 and water. The results show that among the solvents DMSO is the most efficient in promoting the dehydration of fructose to HMF, and no rehydration byproducts such as levulinic acid and formic acid are detected.

  12. Slab mantle dehydrates beneath Kamchatka—Yet recycles water into the deep mantle

    NASA Astrophysics Data System (ADS)

    Konrad-Schmolke, Matthias; Halama, Ralf; Manea, Vlad C.

    2016-08-01

    The subduction of hydrated slab mantle is the most important and yet weakly constrained factor in the quantification of the Earth's deep geologic water cycle. The most critical unknowns are the initial hydration state and the dehydration behavior of the subducted oceanic mantle. Here we present a combined thermomechanical, thermodynamic, and geochemical model of the Kamchatka subduction zone that indicates significant dehydration of subducted slab mantle beneath Kamchatka. Evidence for the subduction of hydrated oceanic mantle comes from across-arc trends of boron concentrations and isotopic compositions in arc volcanic rocks. Our thermodynamic-geochemical models successfully predict the complex geochemical patterns and the spatial distribution of arc volcanoes in Kamchatka assuming the subduction of hydrated oceanic mantle. Our results show that water content and dehydration behavior of the slab mantle beneath Kamchatka can be directly linked to compositional features in arc volcanic rocks. Depending on hydration depth of the slab mantle, our models yield water recycling rates between 1.1 × 103 and 7.4 × 103 Tg/Ma/km corresponding to values between 0.75 × 106 and 5.2 × 106 Tg/Ma for the entire Kamchatkan subduction zone. These values are up to one order of magnitude lower than previous estimates for Kamchatka, but clearly show that subducted hydrated slab mantle significantly contributes to the water budget in the Kamchatkan subduction zone.

  13. Exploring the connection between intermediate-depth seismicity, slab hydration, and dehydration

    NASA Astrophysics Data System (ADS)

    Syracuse, E. M.; Pesicek, J. D.; Zhang, H.; Thurber, C. H.

    2013-12-01

    The dehydration of hydrous minerals has commonly been cited as the cause of intermediate-depth seismicity in subducted crust and mantle, through the process known as dehydration embrittlement. However, recent laboratory and empirical studies have called both the mechanism and seismological observation of this phenomenon into question. In order to assess the global relationship between seismicity, the presence of hydrous and dehydrating minerals, and the thermal state of slabs, we perform double-difference earthquake relocation of earthquakes at the majority of Earth's subduction zones, which reduces the scatter and improves the accuracy of the distributions of slab seismicity. The double-difference relocations are systematically calculated for each subduction zone in a version of the algorithm tomoDD that has been modified to include absolute and differential catalog P, S, and depth phase arrival times from local and teleseismic stations, as well as a three-dimensional global velocity model. Preliminary relocations demonstrate shifts of up to 15 km due to the use of a three-dimensional global velocity model. These relocations also illuminate various types of slab structures, including a range of slab morphologies, potential double seismic zones, and evidence of fault zones within slabs. At each subduction zone, these distributions are compared to previously published two-dimensional thermal and mineralogical models that have been calculated for that particular slab. The findings of these comparisons will be used to develop a set of slab conditions that describe where intermediate-depth seismicity is possible (and observed) at subduction zones.

  14. In-vitro terahertz spectroscopy of rat skin under the action of dehydrating agents

    NASA Astrophysics Data System (ADS)

    Kolesnikov, Aleksandr S.; Kolesnikova, Ekaterina A.; Tuchina, Daria K.; Terentyuk, Artem G.; Nazarov, Maxim; Skaptsov, Alexander A.; Shkurinov, Alexander P.; Tuchin, Valery V.

    2014-01-01

    In the paper we present the results of study of rat skin and rat subcutaneous tumor under the action of dehydrating agents in terahertz (THz) range (15-30 THz). Frustrated Total Internal Reflection (FTIR) spectra were obtained with infrared Fourier spectrometer Nicolet 6700 and then they were recalculated in the transmittance spectra with Omnic software. Experiments were carried out with healthy and xenografted tumor in skin tissue in vitro. As the dehydrating agents 100% glycerol, 40%-water glucose solution, PEG-600, and propylene glycol were used. To determine the effect of the optical clearing agent (OCA), the alterations of terahertz transmittance for the samples were analyzed. The results have shown that PEG-600 and 40%-glucose water solution are the most effective dehydrating agent. The transmittance of healthy skin after PEG-600 application increased approximately by 6% and the transmittance of tumor tissue after PEG- 600 and 40%-glucose water solution application increased approximately by 8%. Obtained data can be useful for further application of terahertz radiation for tumor diagnostics.

  15. Dehydration protection provided by a maternal cuticle improves offspring fitness in the moss Funaria hygrometrica

    PubMed Central

    Budke, Jessica M.; Goffinet, Bernard; Jones, Cynthia S.

    2013-01-01

    Background and Aims In bryophytes the sporophyte offspring are in contact with, nourished from, and partially surrounded by the maternal gametophyte throughout their lifespan. During early development, the moss sporophyte is covered by the calyptra, a cap of maternal gametophyte tissue that has a multilayered cuticle. In this study the effects on sporophyte offspring fitness of removing the maternal calyptra cuticle, in combination with dehydration stress, is experimentally determined. Methods Using the moss Funaria hygrometrica, calyptra cuticle waxes were removed by chemical extraction and individuals were exposed to a short-term dehydration event. Sporophytes were returned to high humidity to complete development and then aspects of sporophyte survival, development, functional morphology, and reproductive output were measured. Key Results It was found that removal of calyptra cuticle under low humidity results in significant negative impacts to moss sporophyte fitness, resulting in decreased survival, increased tissue damage, incomplete sporophyte development, more peristome malformations, and decreased reproductive output. Conclusions This study represents the strongest evidence to date that the structure of the calyptra cuticle functions in dehydration protection of the immature moss sporophyte. The investment in a maternal calyptra with a multilayered cuticle increases offspring fitness and provides a functional explanation for calyptra retention across mosses. The moss calyptra may represent the earliest occurance of maternal protection via structural provisioning of a cuticle in green plants. PMID:23471009

  16. 3-D measurement of osmotic dehydration of isolated and adhered PC-3 cells.

    PubMed

    Yoshimori, Takashi; Takamatsu, Hiroshi

    2009-02-01

    Cell dehydration during freezing results from an elevated concentration of electrolytes in the extracellular medium that is deeply involved in cellular injury. We undertook real-time threedimensional (3-D) observation of osmotic dehydration of cells, motivated by a comparison of cellular responses between isolated cells in suspension and cultured cells adhering to a surface since several studies have suggested a difference in freeze tolerance between cell suspensions and monolayers. A laser confocal scanner was used with a perfusion microscope to capture sectional images of chloromethylbenzamido (DiI)-stained PC-3 cells that were exposed to an increase in NaCl concentration from 0.15 to 0.5M at 23 degrees C. Change in cell volume was determined from reconstructed 3-D images taken every 2.5s. When cells were exposed to an elevated NaCl concentration, isolated cells contracted and markedly distorted from their original spherical shape. In contrast, adhered cells showed only a reduction in height and kept their basal area constant. Apparent membrane hydraulic conductivity did not vary considerably between isolated and adhered cells, suggesting a negligible effect of the cytoskeletal structure on the rate of water transport. The surface area that contributed to water transport in adhered PC-3 cells was nearly equal to or slightly smaller than that present in isolated cells. Therefore, the similarity in properties and dimensions between isolated and adhered cells indicate that there will be similar extents of dehydration, resulting in a similar degree of supercooling during freezing.

  17. Effect of Dehydration on Leakage and Membrane Structure in Lotus corniculatus L. Seeds.

    PubMed

    McKersie, B D; Stinson, R H

    1980-08-01

    Membrane damage as a result of dehydration was studied in Lotus corniculatus L. cv. Carroll seeds which had been pregerminated for 0, 12, and 24 hours prior to dehydration. During reimbibition, desiccation-tolerant (0- and 12-hour) seeds leaked relatively low quantities of all solutes (total electrolytes, potassium, phosphate, sugar, amino acid, and protein). Desiccation-sensitive (24-hour) seeds leaked higher levels, but evidence of selective permeability remained. Membrane damage was not manifested as a complete removal of the diffusion barrier, although its permeability properties were dramatically altered. Consequently, the plasmalemma was not ruptured or torn by the dehydration treatment, but a more subtle structural alteration occurred.The possibility that seed membranes form a hexagonal rather than a lamellar phase at moisture contents below 20% was investigated by x-ray diffraction. Phospholipids were extracted from desiccation-tolerant (0-hour) and desiccation-sensitive (24-hour) seeds and hydrated to 5, 10, 20, and 40% water. This phospholipid-water system was examined using low-and wide-angle x-ray diffraction and was found to be exclusively lamellar, even at 5% water. Consequently, membrane damage and the leakage of cytoplasmic solutes from seeds cannot be explained by the formation of a hexagonal phase by membrane phospholipids.

  18. Cation regulation by the terrestrial isopod Armadillidium vulgare (Crustacea: Isopoda: Oniscidea) during dehydration in air.

    PubMed

    Koh, Huishan; Wright, Jonathan

    2011-06-01

    Many terrestrial arthropods display tight osmotic and ionic regulation of the hemolymph during dehydration. In this study, we sought to quantify the level of regulation of the major hemolymph cations in the terrestrial isopod Armadillidium vulgare (Isopoda, Oniscidea). Inulin space measurements showed that the hemolymph comprises 52 ± 2.2% of the hydrated water content but contributes 71 ± 9.8% of water losses during desiccation. Hemolymph concentrations of Na+, K+ and Ca²+ were measured in variably dehydrated animals using ion-selective microelectrodes and compared with predicted concentrations assuming no regulation. Na+ and Ca²+ are quite tightly regulated, showing respective concentration increases of 20.8% and 7.1% following a 50% reduction in hemolymph volume, but K+ showed no measurable regulation. The excreted cation fraction during desiccation is negligible. Sites of ion sequestration were examined by injecting ²²Na and ⁴⁵Ca into the hemolymph of hydrated animals and assaying tissue-specific activities following dehydration. Na+ is apparently sequestered non-specifically by an unknown mechanism. Ca²+ accumulates in the dorsal somatic tissues, possibly in the calcium pool of the cuticle. How A. vulgare avoids significant disruptions of E(m) and neuromuscular function in the absence of K+ regulation, and how it sequesters Na+, both pose intriguing challenges for future work.

  19. Process optimization for osmo-dehydrated carambola (Averrhoa carambola L) slices and its storage studies.

    PubMed

    Roopa, N; Chauhan, O P; Raju, P S; Das Gupta, D K; Singh, R K R; Bawa, A S

    2014-10-01

    An osmotic-dehydration process protocol for Carambola (Averrhoacarambola L.,), an exotic star shaped tropical fruit, was developed. The process was optimized using Response Surface Methodology (RSM) following Central Composite Rotatable Design (CCRD). The experimental variables selected for the optimization were soak solution concentration (°Brix), soaking temperature (°C) and soaking time (min) with 6 experiments at central point. The effect of process variables was studied on solid gain and water loss during osmotic dehydration process. The data obtained were analyzed employing multiple regression technique to generate suitable mathematical models. Quadratic models were found to fit well (R(2), 95.58 - 98.64 %) in describing the effect of variables on the responses studied. The optimized levels of the process variables were achieved at 70°Brix, 48 °C and 144 min for soak solution concentration, soaking temperature and soaking time, respectively. The predicted and experimental results at optimized levels of variables showed high correlation. The osmo-dehydrated product prepared at optimized conditions showed a shelf-life of 10, 8 and 6 months at 5 °C, ambient (30 ± 2 °C) and 37 °C, respectively.

  20. Transcriptome analysis of leaf and root of rice seedling to acute dehydration

    PubMed Central

    2013-01-01

    Background Water deficiency is one of the most serious worldwide problems for agriculture. Recently, it has become more serious and outspread, which urgently requires the production of drought-tolerant plants. Microarray experiments using mRNA from air-dried leaves and roots of rice were performed in an attempt to study genes involved in acute dehydration response. Results Set of 10,537 rice genes was significantly up- or down-regulated in leaves or roots under the treatment. Gene Ontology analysis highlighted gene expression during acute dehydration response depending on organ types and the duration of stress. Rice responded by down-regulating many processes which are mainly involved in inhibiting growth and development. On the other hand, phytohormones (ABA, cytokinin, brassinosteroid) and protective molecules were induced to answer to multiple stresses. Leaves induced more genes than roots but those genes were scattered in various processes, most significantly were productions of osmoprotectants and precursors for important pathways in roots. Roots up-regulated fewer genes and focused on inducing antioxidants and enhancing photosynthesis. Myb, zf-C3HC4, and NAM were most strongly affected transcription factors with the dominance of leaf over root. Conclusions Leaf and root tissues shared some common gene expression during stress, with the purpose of enhancing protective systems. However, these two tissues appeared to act differently in response to the different level of dehydration they experience. Besides, they can affect each other via the signaling and transportation system. PMID:24341907

  1. Protection of the photosynthetic apparatus against dehydration stress in the resurrection plant Craterostigma pumilum.

    PubMed

    Zia, Ahmad; Walker, Berkley J; Oung, Hui Min Olivia; Charuvi, Dana; Jahns, Peter; Cousins, Asaph B; Farrant, Jill M; Reich, Ziv; Kirchhoff, Helmut

    2016-09-01

    The group of homoiochlorophyllous resurrection plants evolved the unique capability to survive severe drought stress without dismantling the photosynthetic machinery. This implies that they developed efficient strategies to protect the leaves from reactive oxygen species (ROS) generated by photosynthetic side reactions. These strategies, however, are poorly understood. Here, we performed a detailed study of the photosynthetic machinery in the homoiochlorophyllous resurrection plant Craterostigma pumilum during dehydration and upon recovery from desiccation. During dehydration and rehydration, C. pumilum deactivates and activates partial components of the photosynthetic machinery in a specific order, allowing for coordinated shutdown and subsequent reinstatement of photosynthesis. Early responses to dehydration are the closure of stomata and activation of electron transfer to oxygen accompanied by inactivation of the cytochrome b6 f complex leading to attenuation of the photosynthetic linear electron flux (LEF). The decline in LEF is paralleled by a gradual increase in cyclic electron transport to maintain ATP production. At low water contents, inactivation and supramolecular reorganization of photosystem II becomes apparent, accompanied by functional detachment of light-harvesting complexes and interrupted access to plastoquinone. This well-ordered sequence of alterations in the photosynthetic thylakoid membranes helps prepare the plant for the desiccated state and minimize ROS production.

  2. Proteomic analysis of leaf proteins during dehydration of the resurrection plant Xerophyta viscosa.

    PubMed

    Ingle, Robert A; Schmidt, Ulrike G; Farrant, Jill M; Thomson, Jennifer A; Mundree, Sagadevan G

    2007-04-01

    The desiccation-tolerant phenotype of angiosperm resurrection plants is thought to rely on the induction of protective mechanisms that maintain cellular integrity during water loss. Two-dimensional (2D) sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the Xerophyta viscosa Baker proteome was carried out during dehydration to identify proteins that may play a role in such mechanisms. Quantitative analysis revealed a greater number of changes in protein expression levels at 35% than at 65% relative water content (RWC) compared to fully hydrated plants, and 17 dehydration-responsive proteins were identified by tandem mass spectrometry (MS). Proteins showing increased abundance during drying included an RNA-binding protein, chloroplast FtsH protease, glycolytic enzymes and antioxidants. A number of photosynthetic proteins declined sharply in abundance in X. viscosa at RWC below 65%, including four components of photosystem II (PSII), and Western blot analysis confirmed that two of these (psbP and Lhcb2) were not detectable at 30% RWC. These data confirm that poikilochlorophylly in X. viscosa involves the breakdown of photosynthetic proteins during dismantling of the thylakoid membranes. In contrast, levels of these photosynthetic proteins were largely maintained during dehydration in the homoiochlorophyllous species Craterostigma plantagineum Hochst, which does not dismantle thylakoid membranes on drying.

  3. Support Effects on Bronsted acid site densities and alcohol dehydration turnover rates on tungsten oxide domains

    SciTech Connect

    Macht, Josef; Baertsch, Chelsey D.; May-Lozano, Marcos; Soled, Stuart L.; Wang, Yong; Iglesia, Enrique

    2005-03-01

    Initial activity and acid site density of several WAl, WSi (MCM41) and one WSn sample were determined. Trans/cis 2-butene selectivity is dependent on the support. Presumably, these differences are due to subtle differences in base strengths. 2-Butanol dehydration rates (per W-atom) reached maximum values at intermediate WOx surface densities on WAl, as reported for 2-butanol dehydration reactions on WZr. Titration results indicate that Bronsted acid sites are required for 2-butanol dehydration on WAl, WSi and WSn. UV-visible studies suggest that WAl is much more difficult to reduce than WZr. The detection of reduced centers on WAl, the number of which correlates to Bronsted acid site density and catalyst activity, as well as the temperature dependence of Bronsted acid site density indicate the in-situ formation of these active sites. We infer that this mechanism is common among all supported WOx samples described in this study. Turnover rates are a function of Bronsted acid site density only. High acid site densities lead to high turnover rates. Higher active site densities may cause stronger conjugate bases, as a higher electron density has to be stabilized, and thus weaker acidity, enabling a faster rate of product desorption. The maximum achievable active site density is dependent on the support. WZr reaches a higher active site density than WAl.

  4. Crystallization, dehydration and preliminary X-ray analysis of excisionase (Xis) proteins cooperatively bound to DNA

    SciTech Connect

    Sam, My D.; Abbani, Mohamad A.; Cascio, Duilio; Johnson, Reid C.; Clubb, Robert T.

    2006-08-01

    This paper describes the crystallization, dehydration and preliminary X-ray data analysis of a complex containing several bacteriophage lambda excisionase (Xis) proteins cooperatively bound to a 33-mer DNA duplex (Xis–DNA{sup X1-X2}). This paper describes the crystallization, dehydration and preliminary X-ray data analysis of a complex containing several bacteriophage lambda excisionase (Xis) [Bushman et al. (1984 ▶). Cell, 39, 699–706] proteins cooperatively bound to a 33-mer DNA duplex (Xis–DNA{sup X1-X2}). Xis is expected to recognize this regulatory element in a novel manner by cooperatively binding and distorting multiple head-to-tail orientated DNA-binding sites. Crystals of this complex belonged to space group P3{sub 1}21 or P3{sub 2}21, with unit-cell parameters a = b = 107.7, c = 73.5 Å, α = β = 90, γ = 120°. Based on the unit-cell parameters for the asymmetric unit, V{sub M} is 3.0 Å{sup 3} Da{sup −1}, which corresponds to a solvent content of ∼59%. The approaches used to crystallize the unusually long DNA fragment in the complex and the dehydration technique applied that dramatically improved the diffraction of the crystals from 10 to 2.6 Å are discussed.

  5. Cryopreservation of Quercus suber somatic embryos by encapsulation-dehydration and evaluation of genetic stability.

    PubMed

    Fernandes, Pedro; Rodriguez, Eleazar; Pinto, Glória; Roldán-Ruiz, Isabel; De Loose, Marc; Santos, Conceição

    2008-12-01

    We describe an encapsulation and dehydration procedure for the cryopreservation of cork oak (Quercus suber L.) somatic embryos that resulted in at least 90% survival. Genetic stability of the regenerated material was assessed by flow cytometry (FCM), amplified fragment length polymorphisms (AFLP) and simple sequence repeats (SSR). Cryopreservation of embryogenic clusters involved encapsulation of each cluster in an alginate bead, followed by a 3-day culture in 0.7 M sucrose and subsequent desiccation to 25 or 35% water content (WC), followed by freezing in liquid nitrogen. Thawed, cryopreserved somatic embryos had high viability and exhibited long-term survival. No morphological differences were observed between somatic embryos desiccated to 25 and 35% WC. Analysis of DNA ploidy stability of control (i.e., encapsulated and dehydrated but not frozen) and cryopreserved material by flow cytometry showed no significant differences. Similarly, DNA-marker analyses (AFLPs and SSR) revealed no significant differences between control and cryopreserved samples at the DNA-sequence level. Nonetheless, because polymorphisms were found between control material and samples cryopreserved and desiccated to 25% WC, the 35% WC method is recommended for cryopreservation of this tissue type. Cryopreservation of Q. suber somatic embryos by this encapsulation-dehydration procedure has potential for use in long-term conservation programs.

  6. Evolution of microstructure and elastic wave velocities in dehydrated gypsum samples

    NASA Astrophysics Data System (ADS)

    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.

  7. Phosphoproteomic dynamics of chickpea (Cicer arietinum L.) reveals shared and distinct components of dehydration response.

    PubMed

    Subba, Pratigya; Barua, Pragya; Kumar, Rajiv; Datta, Asis; Soni, Kamlesh Kumar; Chakraborty, Subhra; Chakraborty, Niranjan

    2013-11-01

    Reversible protein phosphorylation is a ubiquitous regulatory mechanism that plays critical roles in transducing stress signals to bring about coordinated intracellular responses. To gain better understanding of dehydration response in plants, we have developed a differential phosphoproteome 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 phosphorylation status of a large repertoire of proteins were monitored. The proteins were resolved by 2-DE and stained with phosphospecific fluorescent Pro-Q Diamond dye. Mass spectrometric analysis led to the identification of 91 putative phosphoproteins, presumably involved in a variety of functions including cell defense and rescue, photosynthesis and photorespiration, molecular chaperones, and ion transport, among others. Multiple sites of phosphorylation were predicted on several key elements, which include both the regulatory as well as the functional proteins. A critical survey of the phosphorylome revealed a DREPP (developmentally regulated plasma membrane protein) plasma membrane polypeptide family protein, henceforth designated CaDREPP1. The transcripts of CaDREPP1 were found to be differentially regulated under dehydration stress, further corroborating the proteomic results. This work provides new insights into the possible phosphorylation events triggered by the conditions of progressive water-deficit in plants.

  8. Study on ESR and inter-related properties of vacuum-dehydrated nanotubed titanic acid

    NASA Astrophysics Data System (ADS)

    Zhang, Shunli; Li, Wei; Jin, Zhensheng; Yang, Jianjun; Zhang, Jingwei; Du, Zuliang; Zhang, Zhijun

    2004-04-01

    Nanotubed titanic acid (H 2Ti 2O 4(OH) 2) is a novel kind of material. The electron spin resonance (ESR) and inter-related properties of its vacuum-dehydrated product were investigated by means of transmission electron microscopic, X-ray diffraction, ESR, diffuse reflectance spectra. The results showed that after treatment under vacuum (-0.1 MPa) at 100°C, single-electron-trapped oxygen vacancies (SETOV), characterized by a symmetrical ESR signal ( g=2.003), were generated in nanotubed H 2Ti 2O 4(OH) 2 crystal lattice. The g=2.003 ESR signal intensity ( IESR) increased with treatment time. SETOV played the role of F centers, the visible-light absorption power of vacuum-dehydrated H 2Ti 2O 4(OH) 2 was proportional to IESR. During vacuum dehydration at 100°C, the H 2Ti 2O 4(OH) 2 nanotubes shortened but its crystalline form kept unchanged. The formation mechanism of SETOV was discussed.

  9. Reduction in plasma vasopressin levels of dehydrated rats following acute stress

    NASA Technical Reports Server (NTRS)

    Keil, L. C.; Severs, W. B.

    1977-01-01

    Results are presented for an investigation directed to substantiate and extend preliminary findings of stress-induced reduction in plasma arginine vasopressin (pAVP). Since normally hydrated rats have very low levels of pAVP, it is difficult to measure reliably any decrease in pAVP that may result from stress. To overcome this problem, the pAVP levels of the tested rats were raised by dehydration prior to application of stress. A radioimmunoassay for pAVP is described and used to determine the levels of vasopressin in the plasma of nondehydrated and dehydrated rats after exposure to ether or acceleration stress. Plasma pAVP is also determined in rats following nicotine administration. It is shown that exposure of nondehydrated rats to ether or acceleration stress does not elicit any significant alterations in circulating pAVP levels while nicotine injections stimulate a marked increase. In particular, ether and acceleration stress produce a rapid reduction in the pAVP level of dehydrated rats, the decrease being observed in both large and small animals. The mechanism for this reduction in pAVP level following stress is yet unknown.

  10. Chemical sensor platform for non-invasive monitoring of activity and dehydration.

    PubMed

    Solovei, Dmitry; Žák, Jaromír; Majzlíková, Petra; Sedláček, Jiří; Hubálek, Jaromír

    2015-01-14

    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.

  11. Validation analysis of a geriatric dehydration screening tool in community-dwelling and institutionalized elderly people.

    PubMed

    Rodrigues, Susana; Silva, Joana; Severo, Milton; Inácio, Cátia; Padrão, Patrícia; Lopes, Carla; Carvalho, Joana; do Carmo, Isabel; Moreira, Pedro

    2015-03-02

    Dehydration is common among elderly people. The aim of this study was to perform validation analysis of a geriatric dehydration-screening tool (DST) in the assessment of hydration status in elderly people. This tool was based on the DST proposed by Vivanti et al., which is composed by 11 items (four physical signs of dehydration and seven questions about thirst sensation, pain and mobility), with four questions extra about drinking habits. The resulting questionnaire was evaluated in a convenience sample comprising institutionalized (n=29) and community-dwelling (n=74) elderly people. Urinary parameters were assessed (24-h urine osmolality and volume) and free water reserve (FWR) was calculated. Exploratory factor analysis was used to evaluate the scale's dimensionality and Cronbach's alpha was used to measure the reliability of each subscale. Construct's validity was tested using linear regression to estimate the association between scores in each dimension and urinary parameters. Two factors emerged from factor analysis, which were named "Hydration Score" and "Pain Score", and both subscales showed acceptable reliabilities. The "Hydration Score" was negatively associated with 24-h urine osmolality in community-dwelling; and the "Pain Score" was negatively associated with 24-h urine osmolality, and positively associated with 24-h urine volume and FWR in institutionalized elderly people.

  12. The Effect of Drinking on Plasma Vasopressin and Renin in Dehydrated Human Subjects

    NASA Technical Reports Server (NTRS)

    Geelen, G.; Keil, L. C.; Kravik, S. E.; Wade, C. E.; Thrasher, T. N.; Barnes, P. R.; Pyka, G.; Nesvig, C.; Greenleaf, J. E.

    1996-01-01

    Oropharyngeal mechanisms activated by drinking have been shown to induce a rapid decline in plasma vasopressin which preceeds postabsorptive changes in plasma composition in the dehydrated dog. The present study was undertaken to determine what factor(s) inhibit(s) vasopressin secretion after rehydration in water deprived human subjects. Hematocrit (Hct) and hemoglobin (Hb) were determined on the day of the experiment, together with electrolytes and osmolalities which were measured on freshly separated serum. Plasma was immediately frozen and further analyzed by radioimmunoassay for renin activity (PRA), vasopressin (AVP), and aldosterone. The data were analyzed using an analysis of variance for repeated measurements and significant differences between the dehydrated control period and various time points after the start of rehydration were determined using a multiple-range test. began and reached water replete levels 15 minutes after drinking in the absence of any detectable decline in serum sodium or osmolality, we conclude that 427 oropharyngeal factors, alone or combined with gastric distension account for the extremely rapid inhibition of AVP secretion after drinking in the water-deprived human, as has been shown to be the case in dogs. Our findings are also in agreement wiht the recent demonstration that at the onset of drinking in the dehydrated monkey, there is an abrupt fall in plasma AVP concentration associated with a considerable decrease in the firing rate of the supraoptic neurosecretory neurons.

  13. Challenges of linking chronic dehydration and fluid consumption to health outcomes.

    PubMed

    Armstrong, Lawrence E

    2012-11-01

    The purpose of this article is to review the effects of chronic mild dehydration and fluid consumption on specific health outcomes including obesity. The electronic databases PubMed and Google Scholar were searched for relevant literature published from the time of their inception to 2011, with results restricted to studies performed on human subjects and reports in the English language. Key words included the following: dehydration, hypohydration, water intake, fluid intake, disease, and the names of specific disease states. Strength of evidence categories were described for 1) medical conditions associated with chronic dehydration or low daily water intake, and 2) randomized-controlled trials regarding the effects of increased water consumption on caloric intake, weight gain, and satiety. This process determined that urolithiasis is the only disorder that has been consistently associated (i.e., 11 of 13 publications) with chronic low daily water intake. Regarding obesity and type 2 diabetes, evidence suggests that increased water intake may reduce caloric intake for some individuals. Recommendations for future investigations include measuring total fluid intake (water + beverages + water in solid food), conducting randomized-controlled experiments, identifying novel hydration biomarkers, and delineating hydration categories.

  14. From molecular dehydration to excess volumes of phase-separating PNIPAM solutions.

    PubMed

    Philipp, Martine; Kyriakos, Konstantinos; Silvi, Luca; Lohstroh, Wiebke; Petry, Winfried; Krüger, Jan K; Papadakis, Christine M; Müller-Buschbaum, Peter

    2014-04-17

    For aqueous poly(N-isopropyl acrylamide) (PNIPAM) solutions, a structural instability leads to the collapse and aggregation of the macromolecules at the temperature-induced demixing transition. The accompanying cooperative dehydration of the PNIPAM chains is known to play a crucial role in this phase separation. We elucidate the impact of partial dehydration of PNIPAM on the volume changes related to the phase separation of dilute to concentrated PNIPAM solutions. Quasi-elastic neutron scattering enables us to directly follow the isotropic jump diffusion behavior of the hydration water and the almost freely diffusing water. As the hydration number decreases from 8 to 2 for the demixing 25 mass % PNIPAM solution, only a partial dehydration of the PNIPAM chains occurs. Dilatation studies reveal that the transition-induced volume changes depend in a remarkable manner on the PNIPAM concentration of the solutions. The excess volume per mole of H2O molecules expelled from the solvation layers of PNIPAM during phase separation probably strongly increases from dilute to concentrated PNIPAM solutions. This finding is qualitatively related to the immense strain-softening previously observed for demixing PNIPAM solutions.

  15. Dehydration of lawsonite could directly trigger earthquakes in subducting oceanic crust.

    PubMed

    Okazaki, Keishi; Hirth, Greg

    2016-02-04

    Intermediate-depth earthquakes in cold subduction zones are observed within the subducting oceanic crust, as well as the mantle. In contrast, intermediate-depth earthquakes in hot subduction zones predominantly occur just below the Mohorovičić discontinuity. These observations have stimulated interest in relationships between blueschist-facies metamorphism and seismicity, particularly through dehydration reactions involving the mineral lawsonite. Here we conducted deformation experiments on lawsonite, while monitoring acoustic emissions, in a Griggs-type deformation apparatus. The temperature was increased above the thermal stability of lawsonite, while the sample was deforming, to test whether the lawsonite dehydration reaction induces unstable fault slip. In contrast to similar tests on antigorite, unstable fault slip (that is, stick-slip) occurred during dehydration reactions in the lawsonite and acoustic emission signals were continuously observed. Microstructural observations indicate that strain is highly localized along the fault (R1 and B shears), and that the fault surface develops slickensides (very smooth fault surfaces polished by frictional sliding). The unloading slope during the unstable slip follows the stiffness of the apparatus at all experimental conditions, regardless of the strain rate and temperature ramping rate. A thermomechanical scaling factor for the experiments is within the range estimated for natural subduction zones, indicating the potential for unstable frictional sliding within natural lawsonite layers.

  16. Response of Bacillus subtilis spores to dehydration and UV irradiation at extremely low temperatures.

    PubMed

    Dose, K; Klein, A

    1996-02-01

    Spores of Bacillus subtilis have been exposed to the conditions of extreme dehydration (argon/silica gel; simulated space vacuum) for up to 12 weeks at 298 K and 80 K in the dark. The inactivation has been correlated with the production of DNA-double strand-breaks. The temperature-dependence of the rate constants for inactivation or production of DNA-double strand-breaks is surprisingly low. Controls kept in the frozen state at 250 K for the same period of time showed no sign of deterioration. In another series of experiments the spores have been UV irradiated (253.7 nm) at 298 K, 200 K and 80 K after exposure to dehydrating conditions for 3 days. Fluence-effect relationships for inactivation, production of DNA-double strand-breaks and DNA-protein cross-links are presented. The corresponding F37-values for inactivation and production of DNA lesions are significantly increased only at 80 K (factor of 4 to 5). The data indicate that the low temperatures that prevail in the outer parts of the Solar System or at the nightside of Mars or the Moon are not sufficiently low to crucially inhibit inactivation by dehydration. Our data place further constraints on the panspermia hypothesis.

  17. Impact of solar dehydration on composition and antioxidant properties of acai (Euterpe oleracea Mart.).

    PubMed

    Sangronis, Elba; Sanabria, Neida

    2011-03-01

    Commercial products derived from the acai fruit (Euterpe oleracea Mart.) are available in Brazil, but in Venezuela, it is only known by ethnic indigenous groups of the Amazon. In this study, acai flour was made by solar dehydration and the effect of processing on the composition, microbiological quality, and antioxidant properties of such flour were evaluated. The fruit was purchased in Puerto Ayacucho, Venezuela, and a portion was manually pulped. Microbiological quality, proximal composition, minerals, polyphenols, tannins, anthocyanins, and antioxidant capacity were evaluated. The remaining portion of fruit was blanched in a solution of ascorbic acid and citric acid at 98 degrees C for 1 min in the same manner, manually pulped, dried by solar dehydration and the acai flour was also analysed. From the composition of the acai flour, its high content of fat (22.9%), protein (13.7%), dietary fibre (20.5%), total polyphenols (1.60 g/kg) and antioxidant capacity (79.97%) stood out. The blanching of the fruit and the solar dehydrating of the acai pulp did not modify the composition, but they improved its microbiological quality and reduced phenolic compounds and antioxidant capacity. The flour obtained is stable and innocuous and could be used to diversify the diet of the indigenous people of the Amazon region.

  18. Characterization of non-stoichiometric hydration and the dehydration behavior of sitafloxacin hydrate.

    PubMed

    Suzuki, Tetsuya; Araki, Tetsuya; Kitaoka, Hiroaki; Terada, Katsuhide

    2012-01-01

    Sitafloxacin (STFX) hydrate is a non-stoichiometric hydrate. The hydration state of STFX hydrate varies non-stoichiometrically depending on the relative humidity and temperature, though X-ray powder diffraction (XRPD) of STFX hydrate was not affected by storing at low and high relative humidities. The detailed properties of crystalline water of STFX hydrate were estimated in terms of hygroscopicity, thermal analysis combined with X-ray powder diffractometry, crystallography and density functional theory (DFT) calculation. STFX hydrate changed the water contents continuously and reversibly from an equivalent amount of dihydrate through that of sesquihydrate depending on the relative humidity at 25°C. Thermal analysis and X-ray powder diffraction (XRPD) simultaneous measurement also revealed that STFX hydrate dehydrated into a hydrated state equivalent to monohydrate by heating up to 100°C, whereas XRPD patterns were slightly affected. This indicated that the crystal structure of STFX hydrate was retained at the dehydration level of monohydrate. Single-crystal X-ray structural analysis showed that two STFX molecules and four water molecule sites were contained in an asymmetric unit. STFX molecules formed a channel structure where water molecules were included. At the partially dehydrated state, at least two of four water molecules were considered to be disordered in occupancy and/or coordinates. Insight into the crystal structure of STFX hydrate stored at low and high relative humidities and geometry of the hydrogen bond were helpful to estimate the origin of non-stoichiometric hydration of STFX hydrate.

  19. Reversible Dehydration Behavior Reveals Coordinatively Unsaturated Metal Sites in Microporous Aluminum Phosphonates

    SciTech Connect

    Kinnibrugh, Tiffany L.; Bakhmutov, Vladimir I.; Clearfield, Abraham

    2014-10-01

    Incorporation of the same ligand into three different aluminum phenylenediphosphonates (Al(H2O)(O3PC6H4PO3H) (1), Al-4(H2O)(2)(O3PC6H4PO3)(3) (2), and Al-4(H2O)(4)(O3PC6H4PO3)(2.84)(OH)(0.64) (3)) was accomplished by varying the synthetic conditions. The compounds have different sorption properties; however, all exhibit reversible dehydration behavior. The structures of the hydrated and dehydrated phases were determined from powder X-ray diffraction data. Compounds 2 and 3 were found to be microporous, while compound 1 was found to be nonporous. The stability of the dehydrated phase and the resulting porosity was found to be influenced by the change in the structure upon loss of water.

  20. Water management by dormant insects: comparisons between dehydration resistance during summer aestivation and winter diapause.

    PubMed

    Benoit, Joshua B

    2010-01-01

    During summer in temperate regions and tropical dry seasons insects are exposed to extended periods with little available water. To counter this dehydration stress, insects have two options. They can either remain active by utilizing mechanisms to function under severe water stress and high temperatures, or they can escape from the stressful environment by exploiting an aestivation mechanism. During aestivation, insects undergo a variety of molecular and biochemical changes to arrest development, reduce metabolism, tolerate high temperatures, and increase their ability to maintain water balance. In this review, I provide a synopsis of known and possible mechanisms utilized by insects to reduce the stress of dehydration during aestivation. Comparative observations of aestivating and diapausing insects are also discussed to assess similarities and differences in the methods used by insects to increase dehydration resistance between these two types of dormancies. Adaptations that alter moisture requirements during diapause (low metabolic rate, increases in osmolytes, shifts in cuticular hydrocarbons, cell membrane restructing) are likely similar to those utilized at the induction and during the maintenance phase of aestivation. Few studies have been conducted on the physiology, particularly the biochemistry and molecular regulation, of aestivating insects, indicating that much more research is needed to fully assess water balance characteristics of insects during aestivation. Whether an insect is in diapause or aestivation, behavioral, biochemical, and physiological adaptations are essential for suppressing water loss and enhancing survival in a desiccated state.

  1. Theoretical study of the reactions of 2-chlorophenol over the dehydrated and hydroxylated silica clusters.

    PubMed

    Pan, Wenxiao; Zhong, Wenhui; Zhang, Dongju; Liu, Chengbu

    2012-01-12

    Silica is the main component of combustion-generated fly ash and is expected to have an important impact on the formation of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in municipal waste incinerators. In this work, we theoretically studied the reactions of 2-chlorinated phenol (2-CP) over the clusters (SiO(2))(3) and (SiO(2))(3)O(2)H(4), which mimic the dehydrated and hydroxylated silica structures, respectively. The dehydrated cluster is much more active toward the attack of 2-CP to form highly stable 2-chlorophenolate than the hydroxylated silica cluster. The further dissociation of chlorophenolates to form CP radicals (CPRs) is calculated to be very difficult. The calculated energy barrier of the reaction of 2-CP over the dehydrated (SiO(2))(3) cluster and IR data are in good agreement with early experimental observations. On the basis of the calculated results, we propose that the formation of PCDD/Fs from CPs over silica surfaces may not involve CPRs, but be relevant to the further conversion of chlorophenolates over silica surfaces. This mechanism is very different from the corresponding reactions mediated by transition metal oxides. The results presented here may be helpful to understand the chemisorption mechanism of CPs on silica surfaces in real waste combustion.

  2. Dehydration and Dehydrogenation of Ethylene Glycol on Rutile TiO2(110)

    SciTech Connect

    Li, Zhenjun; Kay, Bruce D.; Dohnalek, Zdenek

    2013-08-07

    The interactions of ethylene glycol (EG) with partially reduced rutile TiO2(110) surface have been studied using temperature programmed desorption (TPD). The saturation coverage on the surface Ti rows is determined to be 0.43 monolayer (ML), slightly less than one EG per two Ti sites. Most of the adsorbed ethanol (~80%) undergoes further reactions to other products. Two major channels are observed, dehydration yielding ethylene and water and dehydrogenation yielding acetaldehyde and hydrogen. Hydrogen formation is rather surprising as it has not been observed previously on TiO2(110) from simple organic molecules. The coverage dependent yields of ethylene and acetaldehyde correlate well with that of water and hydrogen, respectively. Dehydration dominates at lower EG coverages (< 0.2 ML) and plateaus as the coverage is increased to saturation. Dehydrogenation is observed primarily at higher EG coverages (>0.2 ML). Our results suggest that the observed dehydration and dehydrogenation reactions proceed via different surface intermediates.

  3. Comparison Between the Continuous and Intermittent Heating Methods for Simultaneous Infrared Dry-Blanching and Dehydration of Apple Slices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simultaneous infrared dry-blanching and dehydration (SIRDBD) can be operated in two heating modes, continuous and intermittent heating. Under continuous heating, infrared radiation intensity was kept constant while the product temperature remained constant under intermittent heating in this study. ...

  4. Using Wind and Temperature Fields to Study Dehydration Mechanisms in the Tropical Tropopause Layer

    NASA Technical Reports Server (NTRS)

    Pittman, Jasna; Miller, Timothy; Robertson, Franklin

    2008-01-01

    The tropics are the main region for troposphere-to-stratosphere transport (TST) of air. One of the dominant mechanisms that control tropical TST of water vapor is freeze-drying by the cold tropical tropopause. This mechanism is supported by evidence from satellite observations of the "tape recorder", where seasonal changes in stratospheric water vapor are in phase with seasonal changes in tropopause temperatures in the tropics. Over the last few years, however, the concept of the tropical tropopause has evolved from a single material surface to a layer called the Tropical Tropopause Layer (TTL). A recent hypothesis on dehydration mechanisms suggests that dehydration and entry point into the stratosphere are not always co-located (Holton and Gettelman, 2001). Instead, dehydration can occur during horizontal advection through Lagrangian 'cold pools', or coldest regions along a parcel's trajectory, as air ascends within the TTL while the entry point into the stratosphere occurs at a different geographical location. In this study, we investigate the impact that these Lagrangian cold pools have on TTL moisture. For this purpose, we use in situ measurements of TTL water vapor obtained aboard NASA's WB-57 aircraft over the Eastern Tropical Pacific, and we compare these measurements to minimum saturation water vapor mixing ratios obtained from three-dimensional backward trajectory calculations. Aircraft measurements show frequent unsaturated conditions, which suggest that the entry value of stratospheric water vapor in this region was not set by local saturation conditions. Trajectory calculations, driven by both ECMWF operational analysis and reanalysis winds and temperature fields, are used to explore the impact (e.g., geographical location, timing, dehydration magnitude) of the Lagrangian cold pools intercepted by the parcels sampled by the aircraft. We find noteworthy differences in the location of the Lagrangian cold pools using the two ECMWF data sets, namely

  5. Dehydration, stress, and water consumption of horses during long-distance commercial transport.

    PubMed

    Friend, T H

    2000-10-01

    The aim of this study was to characterize progressive dehydration, stress responses, and water consumption patterns of horses transported long distances in hot weather and to estimate recovery time after 30 h of transport. Thirty adult mares and geldings were deprived of access to feed and water for 6 h, blocked by age, sex, breed, and body condition score, and assigned to one of the following treatments: penned, offered water (Penned/Watered, n = 5); penned, no water (Penned, n = 5); transported, offered water (Transported/Watered, two groups of n = 5); or transported, no water (Transported, two groups of n = 5). None of the horses had access to feed while on treatment. A commercial, single-deck, open-top, 15.8-m-long trailer was divided into four compartments to accommodate the two Transported/Watered and two Transported groups at 1.77 m2 per horse. At 8, 17, 22, 27, 30, and 33 h after initiation of transport, the truck returned and stopped for 1 h to allow for data collection and to give the Transported/Watered and Penned/Watered horses 10 min of access to water in individual buckets. Treatments for the non-watered horses (Penned and Transported) were terminated after 30 h due to dehydration and fatigue, whereas the watered horses (Penned/Watered and Transported/Watered) could continue for another 2 h. Mean weight loss after 30 h was greater in the Penned (57.1 kg, 12.8%) and Transported (52.2 kg, 10.3%) groups than in the Transported/Watered (20.7 kg, 4.0%) and Penned/Watered (17 kg, 3.5%) groups (P < 0.0001). Respiration, heart rate, sodium, chloride, total protein, and osmolality were significantly elevated in the non-watered horses (P < 0.0001), and sodium, chloride, total protein, and osmolality greatly exceeded normal reference ranges, indicating severe dehydration. Although not statistically significant, the horses penned in full sun, with or without water, had a dehydration response that was slightly greater than that of the transported horses. Plasma

  6. New experimental data on the antigorite dehydration in silica enriched serpentinite

    NASA Astrophysics Data System (ADS)

    Padrón-Navarta, José Alberto; Hermann, Jörg; Garrido, Carlos J.; López Sánchez-Vizcaíno, Vicente; Gómez-Pugnaire, María. Teresa

    2010-05-01

    There is a growing body of evidences for complex interaction between highly reactive fluids and ultramafic lithologies. Silica metasomatism, for example, can occur at the basement of slow-spreading mid-ocean ridges and during prograde metamorphism of chaotically intermixing in mélange zones of ultramafic rocks, metasediments and metabasites in subduction settings. The resulting assemblage diagnostic of metaperidotites that experienced silica metasomatism are talc-schist and talc-bearing serpentinite. These lithologies may hence be common in subduction settings and will undergo different dehydration reactions. Antigorite and talc will react at lower temperature than the terminal antigorite dehydration. Although this reaction is not expected to be as important in the transfer of water to mantle depth as the breakdown of antigorite, it represents nevertheless a dehydration event in subduction zones that has not been considered so far. We anticipate that this reaction might be particularly important for the fore-arc mantle wedge. Piston cylinder experiments were performed to constrain the pressure and temperature conditions for two high-pressure antigorite dehydration reactions found in silica-enriched serpentinites from Cerro del Almirez (Nevado-Filábride Complex, Betic Cordillera, southern Spain) [1]. At 630-660°C and pressures greater than 1.6 GPa, antigorite first reacts with talc to form orthopyroxene ± chlorite + fluid. We show that orthopyroxene + antigorite is restricted to high-pressure metamorphism of silica-enriched serpentinite. This uncommon assemblage is helpful in constraining metamorphic conditions in cold subduction environments, where antigorite serpentinites have no diagnostic assemblages over a large range in PT space [2,3]. The second dehydration reaction leads to the breakdown of antigorite to olivine + orthopyroxene + chlorite + fluid. The maximum stability of antigorite is found at 680°C at 1.9 GPa, which also corresponds to the maximum

  7. Dehydration softening of serpentine and its roles in the intermediate-depth earthquakes

    NASA Astrophysics Data System (ADS)

    Shimizu, I.; Watanabe, Y.; Michibayashi, K.

    2010-12-01

    A popular hypothesis for the occurrence of double seismic zones in subducting slabs, located at the depth of about 50-200 km, is dehydration embrittlement of serpentinized mantle. Brittle failure of serpentinite has been attributed to excess pore fluid pressure caused by dehydration reaction (Raleigh and Paterson, 1965, JGR; Murrell and Ismail, 1976, Tectonophysics). However, in previous deformation experiments of serpentinites and other hydrous minerals using gas-medium apparatus, confining pressure was limited to 500 MPa, which corresponds to the depth of the middle crust (~15 km). It is questionable if the same mechanism could be effective in subducting slabs at higher pressures. We conducted constant strain-rate experiments of a serpentinite sample, which consists of almost pure antigorite, using solid-medium deformation apparatus. Cylindrical specimens of serpentinite with the diameter of 10 mm and the length of 15 mm were cut from the serpentinite sample and jacketed in Ag tubes. Deformation experiments were conducted at 500 oC and 700 oC under the confining pressure of 800 MPa. The temperature of the dehydration reaction is about 650 oC at this pressure. The strain rate ranges from 3.3x10-5 to 2x10-4 sec-1. At 500 oC, antigorite was very hard and not yielded even after differential stress exceeded 900 MPa. The samples deformed at 700 oC without pre-heating exhibited brittle failures and strain hardening. Dehydration reaction had not occurred in these samples. On the contrary, samples deformed at 700 oC after static heating exhibited steady creep behaviors. The yield strength of preheated samples were 200-280 MPa. The differential stress was slightly increased when the sample strain exceeds 5%. Velocity step tests indicated that the yield stress is insensitive to the strain rate. In the pre-heated samples, intergranular pores were developed. No cracks nor microfaults were observed after deformation experiments. The color of antigorite changed from dark green

  8. Cryopreservation of embryogenic cell suspensions by encapsulation-vitrification and encapsulation-dehydration.

    PubMed

    Yin, Zhenfang; Chen, Long; Zhao, Bing; Zhu, Yongxing; Wang, Qiaochun

    2012-01-01

    Encapsulation-vitrification and encapsulation-dehydration are two newly developed techniques for cryopreservation of embryogenic cell suspensions. Here, we describe the two protocols using grapevine (Vitis) as a model plant. Cell suspensions at the exponential growth stage cultured in a cell suspension maintenance medium are encapsulated to form beads, each being about 4 mm in diameter and containing 25% cells. In the encapsulation-vitrification procedure, the beads are stepwise precultured in increasing concentrations of sucrose medium up to 0.75 M, with 1 day for each concentration. The precultured beads are treated with a loading solution for 60 min and then dehydrated with plant vitrification solution 2 at 0°C for 270 min before a direct immersion in liquid nitrogen. Following cryostorage, the beads are rapidly rewarmed at 40°C for 3 min and then unloaded with 1 M sucrose solution for 30 min. In the encapsulation-dehydration procedure, the beads are precultured in increasing concentrations of sucrose medium up to 1 M, with 1 day for each concentration, and then maintained on 1 M sucrose medium for 3 days. The precultured beads are dehydrated for 6 h under a sterile air flow, prior to rapid freezing in liquid nitrogen. The freezing and rewarming procedures are the same as used in the encapsulation-vitrification technique. The unloaded beads from encapsulation-vitrification and rewarmed beads from encapsulation-dehydration are postcultured on a recovery medium for 3 days at 25°C in the dark for survival. Surviving cells are transferred to a regrowth medium to induce cell proliferation. Embryogenic cell suspensions are reestablished by suspending the cells in a cell suspension maintenance medium maintained on a gyratory shaker at 25°C in the dark. For plant regeneration, surviving cells are transferred from the recovery medium to an embryo maturation medium and maintained at 25°C under light conditions. Embryos at the torpedo stage are cultured on a rooting

  9. Dehydration accelerates reductions in cerebral blood flow during prolonged exercise in the heat without compromising brain metabolism.

    PubMed

    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 < 0.05). However, cerebral metabolism remained stable through enhanced O2 and glucose extraction (P < 0.05). External carotid artery flow increased for 1 h but declined before exhaustion. Fluid ingestion maintained cerebral and extracranial perfusion throughout nonfatiguing exercise. During exhaustive exercise, however, euhydration delayed but did not prevent the decline in cerebral perfusion. In conclusion, during prolonged exercise in the heat, 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 .

  10. Photosynthetic parameters of sexually different parts of Porphyra katadai var. hemiphylla (Bangiales, Rhodophyta) during dehydration and re-hydration.

    PubMed

    Lin, A-Peng; Wang, Guang-Ce; Yang, Fang; Pan, Guang-Hua

    2009-03-01

    Physiological data from extreme habitat organisms during stresses are vital information for comprehending their survival. The intertidal seaweeds are exposed to a combination of environmental stresses, the most influential one being regular dehydration and re-hydration. Porphyra katadai var. hemiphylla is a unique intertidal macroalga species with two longitudinally separated, color distinct, sexually different parts. In this study, the photosynthetic performance of both PSI and PSII of the two sexually different parts of P. katadai thalli during dehydration and re-hydration was investigated. Under low-grade dehydration the variation of photosystems of male and female parts of P. katadai were similar. However, after the absolute water content reached 42%, the PSI of the female parts was nearly shut down while that of the male parts still coordinated well and worked properly with PSII. Furthermore, after re-hydration with a better conditioned PSI, the dehydrated male parts were able to restore photosynthesis within 1 h, while the female parts did not. It is concluded that in P. katadai the susceptibility of photosynthesis to dehydration depends on the accommodative ability of PSI. The relatively lower content of phycobiliprotein in male parts may be the cause for a stronger PSI after severe dehydration.

  11. Dehydrated hereditary stomatocytosis linked to gain-of-function mutations in mechanically activated PIEZO1 ion channels.

    PubMed

    Albuisson, Juliette; Murthy, Swetha E; Bandell, Michael; Coste, Bertrand; Louis-Dit-Picard, Hélène; Mathur, Jayanti; Fénéant-Thibault, Madeleine; Tertian, Gérard; de Jaureguiberry, Jean-Pierre; Syfuss, Pierre-Yves; Cahalan, Stuart; Garçon, Loic; Toutain, Fabienne; Simon Rohrlich, Pierre; Delaunay, Jean; Picard, Véronique; Jeunemaitre, Xavier; Patapoutian, Ardem

    2013-01-01

    Dehydrated hereditary stomatocytosis is a genetic condition with defective red blood cell membrane properties that causes an imbalance in intracellular cation concentrations. Recently, two missense mutations in the mechanically activated PIEZO1 (FAM38A) ion channel were associated with dehydrated hereditary stomatocytosis. However, it is not known how these mutations affect PIEZO1 function. Here, by combining linkage analysis and whole-exome sequencing in a large pedigree and Sanger sequencing in two additional kindreds and 11 unrelated dehydrated hereditary stomatocytosis cases, we identify three novel missense mutations and one recurrent duplication in PIEZO1, demonstrating that it is the major gene for dehydrated hereditary stomatocytosis. All the dehydrated hereditary stomatocytosis-associated mutations locate at C-terminal half of PIEZO1. Remarkably, we find that all PIEZO1 mutations give rise to mechanically activated currents that inactivate more slowly than wild-type currents. This gain-of-function PIEZO1 phenotype provides insight that helps to explain the increased permeability of cations in red blood cells of dehydrated hereditary stomatocytosis patients. Our findings also suggest a new role for mechanotransduction in red blood cell biology and pathophysiology.

  12. Dehydration stress-induced oscillations in LEA protein transcripts involves abscisic acid in the moss, Physcomitrella patens.

    PubMed

    Shinde, Suhas; Nurul Islam, M; Ng, Carl K-Y

    2012-07-01

    • Physcomitrella patens is a bryophyte belonging to early diverging lineages of land plants following colonization of land in the Ordovician period. Mosses are typically found in refugial habitats and can experience rapidly fluctuating environmental conditions. The acquisition of dehydration tolerance by bryophytes is of fundamental importance as they lack water-conducting tissues and are generally one cell layer thick. • Here, we show that dehydration induced oscillations in the steady-state transcript abundances of two group 3 late embryogenesis abundant (LEA) protein genes in P. patens protonemata, and that the amplitudes of these oscillations are reflective of the severity of dehydration stress. • Dehydration stress also induced elevations in the concentrations of abscisic acid (ABA), and ABA alone can also induce dosage-dependent oscillatory increases in the steady-state abundance of LEA protein transcripts. Additionally, removal of ABA resulted in rapid attenuation of these oscillatory increases. • Our data demonstrate that dehydration stress-regulated expression of LEA protein genes is temporally dynamic and highlight the importance of oscillations as a robust mechanism for optimal responses. Our results suggest that dehydration stress-induced oscillations in the steady-state abundance of LEA protein transcripts may constitute an important cellular strategy for adaptation to life in a constantly changing environment.

  13. Dehydration softening of serpentine as a trigger of intermediate-depth earthquakes

    NASA Astrophysics Data System (ADS)

    Shimizu, I.; Watanabe, Y.; Michibayashi, K.; Uehara, S.; Takahashi, M.; Katsuta, N.

    2011-12-01

    A popular hypothesis for the occurrence of double seismic zones in subducting slabs is dehydration embrittlement of serpentinized mantle. Deformation experiments of serpentinites using gas-medium apparatus demonstrated the role of pore pressure in the ductile-to-brittle transition at the dehydration temperature (e.g., Raleigh and Paterson, 1965, JGR). However, it is questionable if the same mechanism could be effective in subducting slabs at the depth. Deformation experiments of serpentinites have been also conducted at higher pressure using multi-anvil and Griggs-type apparatus but little is known about the effects of dehydration reaction on the mechanical behavior of serpentinite. We conducted deformation experiments of antigorite-serpentinite (Oeyama ultramafic body, Japan). Cylindrical samples of serpentinite with the diameter of 10 mm and the length of 15 mm were jacketed in Ag tubes and disks. "Slow" and "fast" experiments were conducted at strain rates of 3.3x10-5 sec -1 and 2x10-4 sec-1, respectively. Axial compression tests were conducted at 800 MPa confining pressure using a solid-medium deformation apparatus. The dehydration temperature is about 650 oC at this pressure. Antigorite was hard at 500oC and not yielded up to 900 MPa differential stress. The experimental run at 700oC without pre-heating is characterized by strain hardening. The sample was deformed by foliation-parallel slip, kinking, and micro-faulting of antigorite. On the contrary, samples deformed at 700oC after static heating showed drastic weakening and steady creep behaviors. A velocity step test indicated that the flow stress is insensitive to the strain rate. The deformed samples contain forsterite and enstatite in the antigorite matrix. Antigorite changed in color from dark green to pink, possibly due to highly oxidized atmosphere resulting from free water release. Intergranular pores were well developed. No microcracks or microfaults were observed. No evidence for intracrystalline

  14. Luminescence induced by dehydration of kaolin - Association with electron-spin-active centers and with surface activity for dehydration-polymerization of glycine

    NASA Technical Reports Server (NTRS)

    Coyne, L.; Hovatter, W.; Sweeney, M.

    1983-01-01

    Experimental data concerning emission of light upon dehydration as a function of preheating and pre-gamma-irradiation are correlated with reported studies of electron-spin resonance (ESR) activity after similar pretreatments. The effect of these pretreatments on the kaolin-promoted incorporation of glycine into peptide oligomers in a wet/cold, hot/dry fluctuating environment is compared to their effect on the ESR and luminescent signals. The existence of spectroscopically active centers appears to be loosely anticorrelated with reaction yield; these yields are increased by increasing the overall energy content of the material. It is concluded that some part of the chemical yield is produced by a mechanism involving intrinsic, excited electronic states of the clay crystal lattice. These states may be derived from thermally, interfacially, and/or mechanically induced charge reorganization within interspersed energy levels in the band structure of the material.

  15. Effects of diuretic-induced hypovolemia/isosmotic dehydration on cardiorespiratory responses to hyperthermia and its physical treatment in rabbits.

    PubMed

    Brozmanova, Andrea; Jochem, Jerzy; Javorka, Kamil; Zila, Ivan; Zwirska-Korczala, Krystyna

    2006-03-01

    Under conditions of heat stress and hyperosmotic dehydration, both animals and humans reduce thermoregulatory evaporation and regulate deep body temperature at elevated levels. Regarding the mechanisms, the main role in producing these thermoregulatory changes during dehydration is attributed to the increased osmolality of body fluids, although the role of the decreased plasma volume without changes in plasma osmolality (hypovolemia/isosmotic dehydration) has not been so far investigated. There are also controversial experimental results regarding the effects of dehydration on heat stress-induced cutaneous vasodilation. Therefore, this paper studied the effects of hypovolemia/isosmotic dehydration on cardiorespiratory responses to hyperthermia and its physical treatment in 17 anaesthetized adult rabbits. The animals were divided into two groups: normovolemic group (NV; n = 10) and hypovolemic group (HV; n = 7). In the HV group, hypovolemia/isosmotic dehydration (decrease in plasma volume by 16.1 +/- 1.2%) was induced by furosemide (5 mg kg-1 i.v.) without change in measured plasma Na+ concentration. Hyperthermia (the rise in body temperature (BT) to 42 degrees C by a gradual body surface heating) caused significant increase in minute ventilation (VE) in both groups. However, VE values were significantly higher in the HV rabbits compared to the NV animals despite the lower breathing frequency (p < 0.05). The panting was absent in the HV rabbits at the BT of 42 degrees C, unlike the NV animals. From cardiovascular variables, the vasoconstrictor response in visceral (mesenteric) region during hyperthermia in hypovolemic/isosmotic animals was attenuated (p < 0.05), whereas the heat stress-induced cutaneous vasodilation was not influenced by hypovolemia. Recovery of the BT by body surface cooling was accompanied by further increase in VE in the NV group, whereas VE decreased (p < 0.05) in the HV animals. Cooling led to recovery of the cardiovascular parameters. There

  16. Experimental Studies on Dehydration Embrittlement of Serpentinized Peridotite and Effect of Pressure on Creep of Olivine

    NASA Astrophysics Data System (ADS)

    Xia, Gang

    The origin of intermediate depth earthquakes has been debated for 90 years yet is still under active discussion. These earthquakes are localized in double seismic zones in descending lithosphere; both zones originate very close to oceanic trenches. A leading proposed initiation mechanism for these earthquakes since 1968 has been dehydration embrittlement of serpentine under stress. Despite the considerable evidence favoring this mechanism, a major argument against it has been that the lower seismic zone initiates at ˜40 km depth almost immediately below trenches and there does not appear to be a vehicle to carry water sufficiently deep to hydrate otherwise dry lithosphere. To directly address this problem, an experimental study has been carried out to investigate the minimum amount of serpentine that is required to trigger the dehydration embrittlement instability in serpentinized peridotite at high pressure (1-3 GPa) and temperature (720-750˚C). The results show that embrittlement occurs during dehydration of antigorite (the phase of serpentine stable at elevated pressure) in a wide range of compositions but both nearly dry peridotite and extensively altered peridotite are ductile. Fresh, unaltered, synthetic harzburgite and harzburgite with 4 vol% distributed antigorite are ductile, as are specimens with greater than 65% antigorite. Only compositions between 8 vol% and 65 vol% antigorite develop the instability. We suggest that very small degrees of serpentinization do not release sufficient H 2O to trigger the instability and that extensive serpentinization avoids the instability because soft, ductile, antigorite becomes the interconnected matrix with olivine and pyroxene existing only as isolated crystals. In that case, dehydration simply facilitates flow. These systematics suggest that small amounts of H2O transported down deep normal (bending) faults at trenches are sufficient to enable the instability in the lower seismic zones, thus providing additional

  17. Rehydration with sodium-enriched coconut water after exercise-induced dehydration.

    PubMed

    Ismail, I; Singh, R; Sirisinghe, R G

    2007-07-01

    This crossover study assessed the effectiveness of plain water (PW), sports drink (SD), fresh young coconut water (CW) and sodium-enriched fresh young coconut water (SCW) on whole body rehydration (R) and plasma volume (PV) restoration after exercise-induced dehydration. Ten healthy male subjects ran at 65% of VO2max in an environmental temperature of 32.06 +/- 0.02 degree C with a relative humidity (rh) of 53.32 +/- 0.17% for 90 minutes to lose 3% body weight (BW). During the 2-hour rehydration period, subjects drank, in randomized order, PW, SD, CW or SCW equivalent to 120% of BW lost in three boluses representing 50, 40 and 30% of the fluid lost at 0, 30, and 60 minutes, respectively. In all trials subjects were still somewhat dehydrated even after the 2-hour rehydration period. Indexes of percent rehydration with PW, SD, CW and SCW were 58 +/- 2, 68 +/- 2, 65+/- 2 and 69 +/- 1%, respectively, with significantly better rehydration with SD and SCW. The rehydration indexes for SD and SCW were significantly lower than PW (p < 0.01). PV was restored to euhydration levels after 2 hours of rehydration with SD, CW and SCW but not with PW. The plasma glucose concentration were significantly higher when SD, CW and SCW were ingested. SCW was similar in sweetness to CW and SD but caused less nausea and stomach upset compared to SD and PW. In conclusion, ingesting SCW was as good as ingesting a commercial sports drink for whole body rehydration after exercise-induced dehydration but with better fluid tolerance.

  18. Dehydration of bacteriophages in electrospun nanofibers: effect of excipients in polymeric solutions

    NASA Astrophysics Data System (ADS)

    Koo, Charmaine K. W.; Senecal, Kris; Senecal, Andre; Nugen, Sam R.

    2016-12-01

    Bacteriophages are viruses capable of infecting and lysing target bacterial cells; as such they have potential applications in agriculture for decontamination of foods, food contact surfaces and food rinse water. Although bacteriophages can retain infectivity long-term using lyophilized storage, the process of freeze-drying can be time consuming and expensive. In this study, electrospinning was used for dehydrating bacteriophages in polyvinylpyrrolidone polymer solutions with addition of excipients (sodium chloride, magnesium sulfate, Tris-HCl, sucrose) in deionized water. The high voltage dehydration reduced the infectivity of bacteriophages following electrospinning, with the damaging effect abated with addition of storage media (SM) buffer and sucrose. SM buffer and sucrose also provided the most protection over extended storage (8 weeks; 20 °C 1% relative humidity) by mitigating environmental effects on the dried bacteriophages. Magnesium sulfate however provided the least protection due to coagulation effects of the ion, which can disrupt the native conformation of the bacteriophage protein coat. Storage temperatures (20 °C, 4 °C and -20 °C 1% relative humidity) had a minimal effect while relative humidity had substantial effect on the infectivity of bacteriophages. Nanofibers stored in higher relative humidity (33% and 75%) underwent considerable damage due to extensive water absorption and disruption of the fibers. Overall, following storage of nanofiber mats for eight weeks at ambient temperatures, high infective phage concentrations (106-107 PFU ml-1) were retained. Therefore, this study provided valuable insights on preservation and dehydration of bacteriophages by electrospinning in comparison to freeze drying and liquid storage, and the influence of excipients on the viability of bacteriophages.

  19. Insights on TTL Dehydration Mechanisms from Microphysical Modelling of Aircraft Observations

    NASA Technical Reports Server (NTRS)

    Ueyama, R.; Pfister, L.; Jensen, E.

    2014-01-01

    The Tropical Tropopause Layer (TTL), a transition layer between the upper troposphere and lower stratosphere in the tropics, serves as the entryway of various trace gases into the stratosphere. Of particular interest is the transport of water vapor through the TTL, as WV is an important greenhouse gas and also plays a significant role in stratospheric chemistry by affecting polar stratospheric cloud formation and the ozone budget. While the dominant control of stratospheric water vapor by tropical cold point temperatures via the "freeze-drying" process is generally well understood, the details of the TTL dehydration mechanisms, including the relative roles of deep convection, atmospheric waves and cloud microphysical processes, remain an active area of research. The dynamical and microphysical processes that influence TTL water vapor concentrations are investigated in simulations of cloud formation and dehydration along air parcel trajectories. We first confirm the validity of our Lagrangian models in a case study involving measurements from the Airborne Tropical TRopopause EXperiment (ATTREX) flights over the central and eastern tropical Pacific in Oct-Nov 2011 and Jan-Feb 2013. ERA-Interim winds and seasonal mean heating rates from Yang et al. (2010) are used to advance parcels back in time from the flight tracks, and time-varying vertical profiles of water vapor along the diabatic trajectories are calculated in a one-dimensional cloud model as in Jensen and Pfister (2004) but with more reliable temperature field, wave and convection schemes. The simulated water vapor profiles demonstrate a significant improvement over estimates based on the Lagrangian Dry Point, agreeing well with aircraft observations when the effects of cloud microphysics, subgrid-scale gravity waves and convection are included. Following this approach, we examine the dynamical and microphysical control of TTL water vapor in the 30ºS-30ºN latitudinal belt and elucidate the dominant processes

  20. Physiological Investigation and Transcriptome Analysis of Polyethylene Glycol (PEG)-Induced Dehydration Stress in Cassava

    PubMed Central

    Fu, Lili; Ding, Zehong; Han, Bingying; Hu, Wei; Li, Yajun; Zhang, Jiaming

    2016-01-01

    Cassava is an important tropical and sub-tropical root crop that is adapted to drought environment. However, severe drought stress significantly influences biomass accumulation and starchy root production. The mechanism underlying drought-tolerance remains obscure in cassava. In this study, changes of physiological characters and gene transcriptome profiles were investigated under dehydration stress simulated by polyethylene glycol (PEG) treatments. Five traits, including peroxidase (POD) activity, proline content, malondialdehyde (MDA), soluble sugar and soluble protein, were all dramatically induced in response to PEG treatment. RNA-seq analysis revealed a gradient decrease of differentially expressed (DE) gene number in tissues from bottom to top of a plant, suggesting that cassava root has a quicker response and more induced/depressed DE genes than leaves in response to drought. Overall, dynamic changes of gene expression profiles in cassava root and leaves were uncovered: genes related to glycolysis, abscisic acid and ethylene biosynthesis, lipid metabolism, protein degradation, and second metabolism of flavonoids were significantly induced, while genes associated with cell cycle/organization, cell wall synthesis and degradation, DNA synthesis and chromatin structure, protein synthesis, light reaction of photosynthesis, gibberelin pathways and abiotic stress were greatly depressed. Finally, novel pathways in ABA-dependent and ABA-independent regulatory networks underlying PEG-induced dehydration response in cassava were detected, and the RNA-Seq results of a subset of fifteen genes were confirmed by real-time PCR. The findings will improve our understanding of the mechanism related to dehydration stress-tolerance in cassava and will provide useful candidate genes for breeding of cassava varieties better adapted to drought environment. PMID:26927071

  1. A role of nesfatin-1/NucB2 in dehydration-induced anorexia.

    PubMed

    Yoshimura, Mitsuhiro; Matsuura, Takanori; Ohkubo, Junichi; Maruyama, Takashi; Ishikura, Toru; Hashimoto, Hirofumi; Kakuma, Tetsuya; Mori, Masatomo; Ueta, Yoichi

    2014-07-15

    Nesfatin-1/NucB2, an anorexigenic molecule, is expressed mainly in the hypothalamus, particularly in the supraoptic nucleus (SON) and the paraventricular nucleus (PVN). Nesfatin-1/NucB2 is also expressed in the subfornical organ (SFO). Because the SON and PVN are involved in body fluid regulation, nesfatin-1/NucB2 may be involved in dehydration-induced anorexia. To clarify the effects of endogenous nesfatin-1/NucB2, we studied changes in nesfatin-1/NucB2 mRNA levels in the SFO, SON, and PVN in adult male Wistar rats after exposure to osmotic stimuli by using in situ hybridization histochemistry. Significant increases in nesfatin-1/NucB2 mRNA levels, ∼2- to 3-fold compared with control, were observed in the SFO, SON, and PVN following water deprivation for 48 h, consumption of 2% NaCl hypertonic saline in drinking water for 5 days, and polyethylene glycol-induced hypovolemia. In addition, nesfatin-1/NucB2 expression was increased in response to water deprivation in a time-dependent manner. These changes in nesfatin-1/NucB2 mRNA expression were positively correlated with plasma sodium concentration, plasma osmolality, and total protein levels in all of the examined nuclei. Immunohistochemistry for nesfatin-1/NucB2 revealed that nesfatin-1/NucB2 protein levels were also increased after 48 h of dehydration and attenuated by 24 h of rehydration. Moreover, intracerebroventricular administration of nesfatin-1/NucB2-neutralizing antibody after 48 h of water deprivation resulted in a significant increase in food intake compared with administration of vehicle alone. These results suggested that nesfatin-1/NucB2 is a crucial peptide in dehydration-induced anorexia.

  2. Dehydration-anorexia derives from a reduction in meal size, but not meal number.

    PubMed

    Boyle, Christina N; Lorenzen, Sarah M; Compton, Douglas; Watts, Alan G

    2012-01-18

    The anorexia that results from extended periods of cellular dehydration is an important physiological adaptation that limits the intake of osmolytes from food and helps maintain the integrity of fluid compartments. The ability to experimentally control both the development and reversal of anorexia, together with the understanding of underlying hormonal and neuropeptidergic signals, makes dehydration (DE)-anorexia a powerful model for exploring the interactions of neural networks that stimulate and inhibit food intake. However, it is not known which meal parameters are affected by cellular dehydration to generate anorexia. Here we use continuous and high temporal resolution recording of food and fluid intake, together with a drinking-explicit method of meal pattern analysis to explore which meal parameters are modified during DE-anorexia. We find that the most important factor responsible for DE-anorexia is the failure to maintain feeding behavior once a meal has started, rather than the ability to initiate a meal, which remains virtually intact. This outcome is consistent with increased sensitivity to satiation signals and post-prandial satiety mechanisms. We also find that DE-anorexia significantly disrupts the temporal distribution of meals across the day so that the number of nocturnal meals gradually decreases while diurnal meal number increases. Surprisingly, once DE-anorexia is reversed this temporal redistribution is maintained for at least 4 days after normal food intake has resumed, which may allow increased daily food intake even after normal satiety mechanisms are reinstated. Therefore, DE-anorexia apparently develops from a selective targeting of those neural networks that control meal termination, whereas meal initiation mechanisms remain viable.

  3. Survival and growth of epidemically successful and nonsuccessful Salmonella enterica clones after freezing and dehydration.

    PubMed

    Müller, Karoline; Aabo, Søren; Birk, Tina; Mordhorst, Hanne; Bjarnadóttir, Björg; Agersø, Yvonne

    2012-03-01

    The spread of epidemically successful nontyphoidal Salmonella clones has been suggested as the most important cause of salmonellosis in industrialized countries. Factors leading to the emergence of success clones are largely unknown, but their ability to survive and grow after physical stress may contribute. During epidemiological studies, a mathematical model was developed that allowed estimation of a factor (q) accounting for the relative ability of Salmonella serovars with different antimicrobial resistances to survive in the food chain and cause human disease. Based on this q-factor, 26 Salmonella isolates were characterized as successful or nonsuccessful. We studied the survival and growth of stationary- and exponential-phase cells of these isolates after freezing for up to 336 days in minced meat. We also investigated survival and growth after dehydration at 10°C and 82% relative humidity (RH) and 25°C and 49% RH for 112 days. Stationary-phase cells were reduced by less than 1 log unit during 1 year of freezing, and growth was initiated with an average lag phase of 1.7 h. Survival was lower in exponentialphase cells, but lag phases tended to be shorter. High humidity and low temperature were less harmful to Salmonella than were low humidity and high temperature. Tolerance to adverse conditions was highest for Salmonella Infantis and one Salmonella Typhimurium U292 isolate and lowest for Salmonella Derby and one Salmonella Typhimurium DT170 isolate. Dehydration, in contrast to freezing, was differently tolerated by the Salmonella strains in this study, but tolerance to freezing and dehydration does not appear to contribute to the emergence of successful Salmonella clones.

  4. Cause of exercise associated muscle cramps (EAMC)--altered neuromuscular control, dehydration or electrolyte depletion?

    PubMed

    Schwellnus, M P

    2009-06-01

    Exercise Associated Muscle Cramps (EAMC) is one of the most common conditions that require medical attention during or immediately after sports events. Despite the high prevalence of this condition the aetiology of EAMC in athletes is still not well understood. The purpose of this review is to examine current scientific evidence in support of (1) the "electrolyte depletion" and "dehydration" hypotheses and (2) the "altered neuromuscular control" hypothesis in the aetiology of EAMC. In this review, scientific evidence will, as far as possible, be presented using evidence-based medicine criteria. This is particularly relevant in this field, as the quality of experimental methodology varies considerably among studies that are commonly cited in support of hypotheses to explain the aetiology of EAMC. Scientific evidence in support of the "electrolyte depletion" and "dehydration" hypotheses for the aetiology of EAMC comes mainly from anecdotal clinical observations, case series totalling 18 cases, and one small (n = 10) case-control study. Results from four prospective cohort studies do not support these hypotheses. In addition, the "electrolyte depletion" and "dehydration" hypotheses do not offer plausible pathophysiological mechanisms with supporting scientific evidence that could adequately explain the clinical presentation and management of EAMC. Scientific evidence for the "altered neuromuscular control" hypothesis is based on evidence from research studies in human models of muscle cramping, epidemiological studies in cramping athletes, and animal experimental data. Whilst it is clear that further evidence to support the "altered neuromuscular control" hypothesis is also required, research data are accumulating that support this as the principal pathophysiological mechanism for the aetiology of EAMC.

  5. Osmotic dehydration of tomato in sucrose solutions: Fick's law classical modeling.

    PubMed

    Bui, Huu-Thuan; Makhlouf, Joseph; Ratti, Cristina

    2009-06-01

    Osmotic dehydration of tomato was modeled by the classical Fick's law including shrinkage, convective resistance at the interface and the presence of water bulk flow. Tomato slices having 8 mm thickness were osmotically dehydrated in sucrose solutions at 50, 60, and 70 degrees Brix and at 35, 45, and 55 degrees C. Other experiments were done in a 70 degrees Brix sucrose solution at 35 degrees C with tomato slices of 4, 6, and 8 mm thickness and at different motion levels (velocities 0, 0.053, and 0.107 m/s). Tomato weight, water content, and degrees Brix of the products were measured as a function of processing time (20, 40, 80, 160, and 320 min). Results showed that temperature, concentration, thickness, and solution movement significantly influenced water loss and sucrose gain during the osmotic dehydration of tomato. The model predicted the modifications of soluble solid content and water content as a function of time in close agreement with the experimental data. Experimental Sherwood number correlations for sucrose and water were determined as Sh(s) = 1.3 Re(0.5)Sc(s) (0.15) and Sh(w) = 0.11 Re(0.5)Sc(w) (0.5), respectively. The effective diffusion coefficients of water (4.97 10(-11)- 2.10 10(-10) m(2)/s) and sucrose (3.18 10(-11)- 1.69 10(-10) m(2)/s) depended only on temperature through an Arrhenius-type relationship.

  6. Enantioselective dehydration of butan-2-ol using zeolite Y modified with dithiane oxides

    SciTech Connect

    Feast, S.; Siddiqui, H.; Bethell, D.

    1997-04-15

    Modification of zeolite H-Y by dithiane oxides (2-R-1,3-dithiane 1-oxide; R = H, CH{sub 3}, C{sub 6}H{sub 5}) is shown to enhance significantly its activity for the acid catalyzed gas phase dehydration of butan-2-ol. The rate enhancement is observed for catalysts that are prepared by adding the dithiane oxide to the zeolite synthesis gel or by adsorption of the dithiane oxide onto commercial samples of zeolite H-Y. The origin of the rate enhancement is considered to result from a specific interaction between the dithiane oxide modifier with both the extra-framework and framework aluminum in the zeolite. Modification of zeolite H-Y with (R)-1,3-dithiane 1-oxide enhances the conversion of (S)-butan-2-ol compared to (R)-butan-2-ol in the temperature range 110-150{degrees}C when the two enantiomers are reacted separately. Modification with (S)-2-phenyl-1,3-dithiane 1-oxide gives a catalyst for which (R)-butan-2-ol is the most reactive of the two enantiomers. Reaction of racemic butan-2-ol over these chirally modified H-Y zeolites demonstrates that this modification procedure makes the zeolite enantiomerically discriminating and one enantiomer preferentially reacts, although both are present in the micropores under the reaction conditions. This effect is considered to be due to enantioselective rate enhancement, since, although the rate of dehydration of both enantiomers is enhanced in the chiral environment, the dehydration rate of one enantiomer is accelerated relative to the other. It is suggested that the effect is due to preferential adsorption at the chiral active site. 34 refs., 7 figs., 6 tabs.

  7. Vapor Phase Dehydration of Glycerol to Acrolein Over SBA-15 Supported Vanadium Substituted Phosphomolybdic Acid Catalyst.

    PubMed

    Viswanadham, Balaga; Srikanth, Amirineni; Kumar, Vanama Pavan; Chary, Komandur V R

    2015-07-01

    Vapor phase dehydration of glycerol to acrolein was investigated over heteropolyacid (HPA) catalysts containing vanadium substituted phosphomolybdic acid (H4PMo11VO40) supported on mesoporous SBA-15. A series of HPA catalysts with HPA loadings varying from 10-50 wt% were prepared by impregnation method on SBA-15 support. The catalysts were characterized by X-ray diffraction, Raman spectroscopy, Fourier Transform infrared spectroscopy, temperature-programmed desorption of NH3, pyridine adsorbed FT-IR spectroscopy, scanning electron microscopy, pore size distribution and specific surface area measurements. The nature of acidic sites was examined by pyridine adsorbed FT-IR spectroscopy. XRD results suggest that the active phase containing HPA was highly dispersed at lower loadings on the support. FT-IR and Raman spectra results confirm that the presence of primary Keggin ion structure of HPA on the support and it was not affected during the preparation of catalysts. Pore size distribution results reveal that all the samples show unimodel pore size distribution with well depicted mesoporous structure. NH3-TPD results suggest that the acidity of catalysts increased with increase of HPA loading. The findings of acidity measurements by FT-IR spectra of pyridine adsorption reveals that the catalysts consist both the Brønsted and Lewis acidic sites and the amount of Brønsted acidic sites are increasing with HPA loading. SBA-15 supported vanadium substituted phosphomolybdic acid catalysts are found to be highly active during the dehydration reaction and exhibited 100% conversion of glycerol (10 wt% of glycerol) and the acrolein selectivity was appreciably changed with HPA active phase loading. The catalytic functionalities during glycerol dehydration are well correlated with surface acidity of the catalysts.

  8. The Citrus ABA signalosome: identification and transcriptional regulation during sweet orange fruit ripening and leaf dehydration

    PubMed Central

    Rodrigo, María J.

    2012-01-01

    The abscisic acid (ABA) signalling core in plants include the cytosolic ABA receptors (PYR/PYL/RCARs), the clade-A type 2C protein phosphatases (PP2CAs), and the subclass III SNF1-related protein kinases 2 (SnRK2s). The aim of this work was to identify these ABA perception system components in sweet orange and to determine the influence of endogenous ABA on their transcriptional regulation during fruit development and ripening, taking advantage of the comparative analysis between a wild-type and a fruit-specific ABA-deficient mutant. Transcriptional changes in the ABA signalosome during leaf dehydration were also studied. Six PYR/PYL/RCAR, five PP2CA, and two subclass III SnRK2 genes, homologous to those of Arabidopsis, were identified in the Citrus genome. The high degree of homology and conserved motifs for protein folding and for functional activity suggested that these Citrus proteins are bona fide core elements of ABA perception in orange. Opposite expression patterns of CsPYL4 and CsPYL5 and ABA accumulation were found during ripening, although there were few differences between varieties. In contrast, changes in expression of CsPP2CA genes during ripening paralleled those of ABA content and agreeed with the relevant differences between wild-type and mutant fruit transcript accumulation. CsSnRK2 gene expression continuously decreased with ripening and no remarkable differences were found between cultivars. Overall, dehydration had a minor effect on CsPYR/PYL/RCAR and CsSnRK2 expression in vegetative tissue, whereas CsABI1, CsAHG1, and CsAHG3 were highly induced by water stress. The global results suggest that responsiveness to ABA changes during citrus fruit ripening, and leaf dehydration was higher in the CsPP2CA gene negative regulators than in the other ABA signalosome components. PMID:22888124

  9. Physiological Investigation and Transcriptome Analysis of Polyethylene Glycol (PEG)-Induced Dehydration Stress in Cassava.

    PubMed

    Fu, Lili; Ding, Zehong; Han, Bingying; Hu, Wei; Li, Yajun; Zhang, Jiaming

    2016-02-25

    Cassava is an important tropical and sub-tropical root crop that is adapted to drought environment. However, severe drought stress significantly influences biomass accumulation and starchy root production. The mechanism underlying drought-tolerance remains obscure in cassava. In this study, changes of physiological characters and gene transcriptome profiles were investigated under dehydration stress simulated by polyethylene glycol (PEG) treatments. Five traits, including peroxidase (POD) activity, proline content, malondialdehyde (MDA), soluble sugar and soluble protein, were all dramatically induced in response to PEG treatment. RNA-seq analysis revealed a gradient decrease of differentially expressed (DE) gene number in tissues from bottom to top of a plant, suggesting that cassava root has a quicker response and more induced/depressed DE genes than leaves in response to drought. Overall, dynamic changes of gene expression profiles in cassava root and leaves were uncovered: genes related to glycolysis, abscisic acid and ethylene biosynthesis, lipid metabolism, protein degradation, and second metabolism of flavonoids were significantly induced, while genes associated with cell cycle/organization, cell wall synthesis and degradation, DNA synthesis and chromatin structure, protein synthesis, light reaction of photosynthesis, gibberelin pathways and abiotic stress were greatly depressed. Finally, novel pathways in ABA-dependent and ABA-independent regulatory networks underlying PEG-induced dehydration response in cassava were detected, and the RNA-Seq results of a subset of fifteen genes were confirmed by real-time PCR. The findings will improve our understanding of the mechanism related to dehydration stress-tolerance in cassava and will provide useful candidate genes for breeding of cassava varieties better adapted to drought environment.

  10. Reversion and dehydration reactions of glucose during the dilute sulfuric acid hydrolysis of cellulose

    SciTech Connect

    Helm, R.F.

    1987-01-01

    The inaccessibility of all glycosidic bonds necessitates industrial conversion schemes which employ a dilute acid catalyst at high temperatures. Process conditions also promote further reactions of glucose via the reversion and dehydration pathways. Quantitative determination of the yields of the major reversion and dehydration products is important for understanding and predicting the amounts of these materials expected under envisioned industrial operating conditions. Microcrystalline cellulose (Avicel) was hydrolyzed with sulfuric acid (0.0-1.25 wt.%), at high temperatures (160-250/sup 0/C), and at a 3:1 liquid-to-solid ratio. The hydrolysis was monitored by evaluating the amount of cellulose remaining and the yields of glucose, solid humin, levulinic acid, formic acid, hydroxymethylfurfural (HMF), and reversion products as a function of the aforementioned reaction conditions. Analysis of the reversion products required the development of a technique for the quantitation of trace carbohydrates in complex mixtures and led to the development of a reduction/permethylation gas chromatographic procedure. Cellulose hydrolysis followed pseudo-homogeneous first-order kinetics. Glucose yield was adequately described as consecutive first-order reactions. Anhydrosugars formed via reversion followed equilibrium reaction kinetics whereas the disaccharides did not. Total reversion product yields approached 10% at 250/sup 0/C. Quantitative determination of the major dehydration products provided important information concerning the destruction of glucose. HMF was produced in up to 12% yields based on the theoretical amount of glucose available, and furfural was detected in up to 5% yields. A carbon mass balance based on the determined product yields revealed that approximately 90% of all carbon was accounted for at maximum glucose yields.

  11. In situ bioremediation of a former natural gas dehydrator site using bioventing/biosparging

    SciTech Connect

    Shamory, B.D.; Lawrence, A.W.; Miller, D.L.

    1995-12-01

    The Gas Research Institute (GRI) is conducting a research program on site remediation and residuals management for natural gas exploration and production (E&P) activities. Biological processes are considered to be a key component of the GRI remedial strategy since most of the chemicals-of-interest in soils and groundwater at E&P sites have been reported to be biodegradable. A bioventing/biosparging field demonstration was conducted over a ten month period at a former glycol dehydrator site, located near Traverse City, Michigan. The chemicals-of-interest at this site were benzene, toluene, ethylbenzene, and xylenes; and alkanes (primarily C{sub 4} through C{sub 10}). The goal of the project was to determine the feasibility of using this technology for dehydrator site remediation and to develop engineering basis of design concepts for applying bioventing/biosparging at other similar sites. Three different air sparging operational modes (pulsed, continuous, and offgas recycle) were tested to determine the optimum process configuration for site remediation. Biodegradation was also evaluated. Operational mode performance was evaluated by situ conducting in situ respirometry studies. Depletion of oxygen and hydrocarbons and production of carbon dioxide were used to calculated biodegradation rates in the vadose and saturated zones. The mass of hydrocarbons biologically degraded was estimated based on these biokinetic rates. In addition, biodegradation was also estimated based on contaminant removal shown by analytical sampling of soil and groundwater and based on other losses attributed to pump and treat and soil vapor extraction systems. In addition, an engineering evaluation of the operating modes is presented. The results of this study suggest that bioventing/biosparging is a feasible technology for in situ remediation of soil and groundwater at gas industry glycol dehydrator sites and that the pulsed operating mode may have an advantage over the other modes.

  12. Impact of postharvest dehydration process of winegrapes on mechanical and acoustic properties of the seeds and their relationship with flavanol extraction during simulated maceration.

    PubMed

    Río Segade, Susana; Torchio, Fabrizio; Gerbi, Vincenzo; Quijada-Morín, Natalia; García-Estévez, Ignacio; Giacosa, Simone; Escribano-Bailón, M Teresa; Rolle, Luca

    2016-05-15

    This study represents the first time that the extraction of phenolic compounds from the seeds is assessed from instrumental texture properties for dehydrated grapes. Nebbiolo winegrapes were postharvest dehydrated at 20°C and 41% relative humidity. During the dehydration process, sampling was performed at 15%, 30%, 45% and 60% weight loss. The extractable fraction and extractability of phenolic compounds from the seeds were determined after simulated maceration. The evolution of mechanical and acoustic attributes of intact seeds was also determined during grape dehydration to evaluate how these changes affected the extraction of phenolic compounds. The extractable content and extractability of monomeric flavanols and proanthocyanidins, as well as the galloylation percentage of flavanols, might be predicted easily and quickly from the mechanical and acoustic properties of intact seeds. This would help in decision-making on the optimal dehydration level of winegrapes and the best management of winemaking of dehydrated grapes.

  13. Dehydration of seabird prey during transport to the colony: Effects on wet weight energy densities

    USGS Publications Warehouse

    Montevecchi, W.A.; Piatt, John F.

    1987-01-01

    We present evidence to indicate that dehydration of prey transported by seabirds from capture sites at sea to chicks at colonies inflates estimates of wet weight energy densities. These findings and a comparison of wet and dry weight energy densities reported in the literature emphasize the importance of (i) accurate measurement of the fresh weight and water content of prey, (ii) use of dry weight energy densities in comparisons among species, seasons, and regions, and (iii) cautious interpretation and extrapolation of existing data sets.

  14. Temperature and water loss affect ADH activity and gene expression in grape berry during postharvest dehydration.

    PubMed

    Cirilli, Marco; Bellincontro, Andrea; De Santis, Diana; Botondi, Rinaldo; Colao, Maria Chiara; Muleo, Rosario; Mencarelli, Fabio

    2012-05-01

    Clusters of Aleatico wine grape were picked at 18°Brix and placed at 10, 20, or 30°C, 45% relative humidity (RH) and 1.5m/s of air flow to dehydrate the berries up to 40% of loss of initial fresh weight. Sampling was done at 0%, 10%, 20%, 30%, and 40% weight loss (wl). ADH (alcohol dehydrogenase) gene expression, enzyme activity, and related metabolites were analysed. At 10°C, acetaldehyde increased rapidly and then declined, while ethanol continued to rise. At 20°C, acetaldehyde and ethanol increased significantly with the same pattern and declined at 40%wl. At 30°C, acetaldehyde did not increase but ethanol increased rapidly already at 10%wl. At the latter temperature, a significant increase in acetic acid and ethyl acetate occurred, while at 10°C their values were low. At 30°C, the ADH activity (ethanol to acetaldehyde direction), increased rapidly but acetaldehyde did not rise because of its oxidation to acetic acid, which increased together with ethyl acetate. At 10°C, the ADH activity increased at 20%wl and continued to rise even at 40%wl, meaning that ethanol oxidation was delayed. At 20°C, the behaviour was intermediate to the other temperatures. The relative expression of the VvAdh2 gene was the highest at 10°C already at 10%wl in a synchrony with the ADH activity, indicating a rapid response likely due to low temperature. The expression subsequently declined. At 20 and 30°C, the expression was lower and increased slightly during dehydration in combination with the ADH activity. This imbalance between gene expression and ADH activity at 10°C, as well as the unexpected expression of the carotenoid cleavage dioxygenase 1 (CCD1) gene, opens the discussion on the stress sensitivity and transcription event during postharvest dehydration, and the importance of carefully monitoring temperature during dehydration.

  15. In vitro terahertz monitoring of muscle tissue dehydration under the action of hyperosmotic agents

    SciTech Connect

    Kolesnikov, A S; Kolesnikova, E A; Popov, A P; Tuchin, V V; Nazarov, M M; Shkurinov, A P

    2014-07-31

    Dehydration of muscle tissue in vitro under the action of biologically compatible hyperosmotic agents is studied using a laser terahertz spectrometer in the frequency range from 0.25 to 2.5 THz. Broadband terahertz absorption and reflection spectra of the bovine skeletal muscle tissue were obtained under the action of glycerol, polyethylene glycol with the molecular weight 600 (PEG-600), and propylene glycol. The presented results are proposed for application in developing the methods of image contrast enhancement and increasing the depth of biological tissue probing with terahertz radiation. (laser biophotonics)

  16. Evaluation of a dehydrated test strip for the detection of yeasts.

    PubMed

    Davies, R R; Savage, M A

    1975-09-01

    Use of a dehydrated test strip for the detection of yeasts is compared with traditional culture on Sabouraud's agar containing 50 mug/ml chloramphenicol. While the selective medium of the strip is satisfactory for the isolation of species of Candida, Torulopsis glabrata grows only very slowly. The strip has the advantage of a long storage life without deterioration, but a high cost may preclude general usage. The numbers of yeasts collected by a bacteriological swab disadvantages of the selective medium, and the value of direct microscopy in the examination of vaginal swabs are discussed.

  17. Influence of dehydrated nanotubed titanic acid on polymer light-emitting diodes with phosphorescent dye

    NASA Astrophysics Data System (ADS)

    Qian, L.; Zhang, T.; Wang, Y. S.; Xu, X. R.; Jin, Z. S.; Du, Z. L.

    2006-01-01

    In this letter, we demonstrate that hole injection and transport in polymer light-emitting diodes with phosphorescent dye Ir(ppy)3 can be significantly enhanced by doping p-type conductive dehydrated nanotubed titanic acid into poly(vinylcarbazole) (PVK) films at 2wt.%. At the same time, both energy transfer and exciton recombination efficiency are improved because of the open and straight conformation of the PVK molecule in the nanocomposite. The performance of these devices was greatly improved, showing higher luminance, enhanced efficiency, and a lower turn-on voltage.

  18. On topotaxy and compaction during antigorite and chlorite dehydration: an experimental and natural study

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    Dehydration reactions result in minerals' replacement and a transient fluid-filled porosity. These reactions involve interface-coupled dissolution-precipitation and might therefore lead to fixed crystallographic orientation relations between reactant (protolith) and product phases (i.e. topotaxy). We investigate these two phenomena in the dehydration of a foliated antigorite (atg) serpentinite by comparing the crystallographic preferred orientation (CPO) developed by olivine (ol), orthopyroxene (opx) and chlorite (chl) during high-pressure antigorite and chlorite dehydration in piston-cylinder experiments and in natural samples recording the dehydration of antigorite (Cerro del Almirez, Betic Cordillera, Spain). Experiments were performed under undrained conditions resulting in fluid-filled porosity and in strong CPO of the prograde minerals, controlled by the pre-existing antigorite CPO in the reactant foliated serpentinite. The orientation of a ol,opx and is parallel to from the protolith. The Cerro del Almirez samples show similar, locally well-developed topotactic relations between orthopyroxene, chlorite and antigorite, but the product CPOs are weaker and more complex at the thin section scale. In contrast to the experiments, olivine from natural samples shows a weak correlation between b ol and the former . We relate the strengthening of local topotactic relations and the weakening of the inherited CPO at a larger scale in natural samples to compaction and associated fluid migration. Microstructural features that might be related to compaction in the natural samples include: (1) smooth bending of the former foliation, (2) gradual crystallographic misorientation (up to 16°) of prismatic orthopyroxene due to buckling by dislocation creep, (3) inversion of enstatite to low clinoenstatite (P21/c) along lamellae and (4) brittle fracturing of prismatic orthopyroxene enclosed by plastically deformed chlorite. The coexistence of orthopyroxene buckling and

  19. Direct Assembly of Prenylated Heteroarenes through a Cascade Minisci Reaction/Dehydration Sequence

    PubMed Central

    Tan, Dong‐Hang; Zeng, Yao‐Fu; Liu, Yao; Lv, Wen‐Xin; Li, Qingjiang

    2016-01-01

    Abstract The prenyl group is an important component in bioactive compounds. Herein, we report the assembly of prenylated heteroarenes through a cascade Minisci reaction and acid‐promoted dehydration sequence. The use of potassium (3‐hydroxy‐3‐methylbut‐1‐yl)trifluoroborate as a new coupling reagent allows the direct introduction of prenyl and 3‐hydroxy‐3‐methylbutyl groups to a wide variety of electron‐deficient heteroarenes. Synthetic application is also demonstrated. PMID:28032022

  20. Muscle blood flow is reduced with dehydration during prolonged exercise in humans

    PubMed Central

    González-Alonso, José; Calbet, José A L; Nielsen, Bodil

    1998-01-01

    The present study examined whether the blood flow to exercising muscles becomes reduced when cardiac output and systemic vascular conductance decline with dehydration during prolonged exercise in the heat. A secondary aim was to determine whether the upward drift in oxygen consumption (V̇O2) during prolonged exercise is confined to the active muscles.Seven euhydrated, endurance-trained cyclists performed two bicycle exercise trials in the heat (35 °C; 40–50% relative humidity; 61 ± 2% of maximal V̇O2), separated by 1 week. During the first trial (dehydration trial, DE), they bicycled until volitional exhaustion (135 ± 4 min, mean ± s.e.m.), while developing progressive dehydration and hyperthermia (3.9 ± 0.3% body weight loss; 39.7 ± 0.2 °C oesophageal temperature, Toes). In the second trial (control trial), they bicycled for the same period of time while maintaining euhydration by ingesting fluids and stabilizing Toes at 38.2 ± 0.1 °C after 30 min exercise.In both trials, cardiac output, leg blood flow (LBF), vascular conductance and V̇O2 were similar after 20 min exercise. During the 20 min-exhaustion period of DE, cardiac output, LBF and systemic vascular conductance declined significantly (8–14%; P < 0.05) yet muscle vascular conductance was unaltered. In contrast, during the same period of control, all these cardiovascular variables tended to increase. After 135 ± 4 min of DE, the 2.0 ± 0.6 l min−1 lower blood flow to the exercising legs accounted for approximately two-thirds of the reduction in cardiac output. Blood flow to the skin also declined markedly as forearm blood flow was 39 ± 8% (P < 0.05) lower in DE vs. control after 135 ± 4 min.In both trials, whole body V̇O2 and leg V̇O2 increased in parallel and were similar throughout exercise. The reduced leg blood flow in DE was accompanied by an even greater increase in femoral arterial-venous O2 (a-vO2) difference.It is concluded that blood flow to the exercising muscles declines

  1. An anomalous hydration/dehydration sequence for the mild generation of a nitrile oxide.

    PubMed

    Nishiwaki, Nagatoshi; Kobiro, Kazuya; Kiyoto, Hideyuki; Hirao, Shotaro; Sawayama, Jun; Saigo, Kazuhiko; Okajima, Yoshikazu; Uehara, Toshiharu; Maki, Asaka; Ariga, Masahiro

    2011-04-21

    A nitrile oxide containing a carbamoyl group is readily generated upon the treatment of 2-methyl-4-nitro-3-isoxazolin-5(2H)-one with water under mild reaction conditions, even in the absence of special reagents. The obtained nitrile oxide undergoes cycloaddition with dipolarophiles, alkynes and alkenes, to afford the corresponding isoxazol(in)es, which are useful intermediates in the synthesis of polyfunctionalized compounds. A plausible mechanism underlying the formation of the nitrile oxide is proposed, which involves an anomalous hydration/dehydration sequence. DFT calculations were also performed to support this mechanism.

  2. Dissolution of two-phase microsystems: Gas and liquid microparticle dissolution and dehydration of biomaterials

    NASA Astrophysics Data System (ADS)

    Duncan, Phillip Brent

    A main focus of this research is to develop techniques to study the dissolution process of two-phase microsystems on a single microparticle basis. This dissertation introduces a systematic approach to investigate the formation of microparticles to fulfill the need for rational design of microspheres for a range of applications. This novel method is based on the micropipet manipulation technique and can essentially test any system, where the continuous phase is a liquid and the dispersed phase is practically any phase, a gas (foam), a liquid (emulsion), or a solid (suspension). It is possible to study single microparticle volumes in the picoliter to nanoliter scale, which is on the same size-scale as particles created in bulk suspensions, microsphere processes, and applications. The ability to create, isolate, observe, and manipulate individual gas, liquid or solid microparticles in a well-defined and controlled liquid environment was found to be ideal to study gas microbubbles and microparticles, liquid microdroplets, and the dehydration of dissolved solutes. Subsequently, one can directly measure the dissolution rate and, when a solute is present, calculate its concentration during the dissolution process. Microbubble or microdroplet dissolution in a second phase is driven by two independent factors, a concentration gradient (undersaturation of the dispersed phase in the continuous phase) and a pressure gradient (due to the Laplace-overpressure inside the microparticle created by the surface tension). Experimentally, each of these driving forces can be independently tested. Both the gas microparticle and pure liquid microdroplet dissolution can be predicted by a simple theory based on the diffusion coefficient and solubility limit of the dispersed phase in the continuous phase. The dehydration of a salt ion solution microdroplet results in the nucleation and growth of a crystal, while the dehydration of proteins leads to glassification of the protein. The water

  3. In vitro terahertz monitoring of muscle tissue dehydration under the action of hyperosmotic agents

    NASA Astrophysics Data System (ADS)

    Kolesnikov, A. S.; Kolesnikova, E. A.; Popov, A. P.; Nazarov, M. M.; Shkurinov, A. P.; Tuchin, V. V.

    2014-07-01

    Dehydration of muscle tissue in vitro under the action of biologically compatible hyperosmotic agents is studied using a laser terahertz spectrometer in the frequency range from 0.25 to 2.5 THz. Broadband terahertz absorption and reflection spectra of the bovine skeletal muscle tissue were obtained under the action of glycerol, polyethylene glycol with the molecular weight 600 (PEG-600), and propylene glycol. The presented results are proposed for application in developing the methods of image contrast enhancement and increasing the depth of biological tissue probing with terahertz radiation.

  4. Separate and combined effects of dehydration and thirst sensation on exercise performance in the heat.

    PubMed

    Cheung, S S; McGarr, G W; Mallette, M M; Wallace, P J; Watson, C L; Kim, I M; Greenway, M J

    2015-06-01

    Using intravenous infusion, we separated the physiologic consequences of 3% body mass dehydration from the conscious awareness of fluid replacement on time trial (TT) performance in the heat. Eleven trained cyclists performed 90 min of steady-state (50% V ˙ O 2 peak ) cycling followed by a self-paced 20-km TT in a hot-dry (35 °C, 10% relative humidity, wind speed 3.0 m/s) environment while euhydrated-not thirsty (EU-NT), euhydrated-thirsty (EU-T), dehydrated-not thirsty (DH-NT), or dehydrated-thirsty (DH-T). Thirst was manipulated by providing (NT) or withholding (T) ad libitum 35 °C water oral rinse. Distinct hydration states existed, with 0.4 ± 0.5% dehydration following the 20-km TT (EU) compared with 3.2 ± 0.6% in DH (P < 0.001). Greater perceived thirst existed in T (7 ± 2 on a 1-9 scale) than NT (4 ± 2, P < 0.001) after the TT. No significant differences in power output existed during the TT between hydration (EU 202.9 ± 36.5 W vs DH 207.0 ± 35.9 W, P = 0.362) and thirst conditions (NT 203.3 ± 35.6 W vs T 206.6 ± 36.8 W, P = 0.548), nor were there differences in completion time (P = 0.832) or pacing profile (P = 0.690). Within the range of up to 3% body mass loss, neither the physiologic effects from lowered hydration status nor the perception of thirst, separately or combined, affected sustained submaximal exercise performance in the heat for a healthy and fit population.

  5. Sustainable Synthesis of Chiral Tetrahydrofurans through the Selective Dehydration of Pentoses

    PubMed Central

    Foster, Robert W; Tame, Christopher J; Bučar, Dejan-Krešimir; Hailes, Helen C; Sheppard, Tom D

    2015-01-01

    l-Arabinose is an abundant resource available as a waste product of the sugar beet industry. Through use of a hydrazone-based strategy, l-arabinose was selectively dehydrated to form a chiral tetrahydrofuran on a multi-gram scale without the need for protecting groups. This approach was extended to other biomass-derived reducing sugars and the mechanism of the key cyclization investigated. This methodology was applied to the synthesis of a range of functionalized chiral tetrahydrofurans, as well as a formal synthesis of 3R-3-hydroxymuscarine. PMID:26407081

  6. Impact of geographic variations of the convective and dehydration center on stratospheric water vapor over the Asian monsoon region

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Fu, Rong; Wang, Tao; Liu, Yimin

    2016-06-01

    The Asian monsoon region is the most prominent moisture center of water vapor in the lower stratosphere (LS) during boreal summer. Previous studies have suggested that the transport of water vapor to the Asian monsoon LS is controlled by dehydration temperatures and convection mainly over the Bay of Bengal and Southeast Asia. However, there is a clear geographic variation of convection associated with the seasonal and intra-seasonal variations of the Asian monsoon circulation, and the relative influence of such a geographic variation of convection vs. the variation of local dehydration temperatures on water vapor transport is still not clear. Using satellite observations from the Aura Microwave Limb Sounder (MLS) and a domain-filling forward trajectory model, we show that almost half of the seasonal water vapor increase in the Asian monsoon LS are attributable to geographic variations of convection and resultant variations of the dehydration center, of which the influence is comparable to the influence of the local dehydration temperature increase. In particular, dehydration temperatures are coldest over the southeast and warmest over the northwest Asian monsoon region. Although the convective center is located over Southeast Asia, an anomalous increase of convection over the northwest Asia monsoon region increases local diabatic heating in the tropopause layer and air masses entering the LS are dehydrated at relatively warmer temperatures. Due to warmer dehydration temperatures, anomalously moist air enters the LS and moves eastward along the northern flank of the monsoon anticyclonic flow, leading to wet anomalies in the LS over the Asian monsoon region. Likewise, when convection increases over the Southeast Asia monsoon region, dry anomalies appear in the LS. On a seasonal scale, this feature is associated with the monsoon circulation, convection and diabatic heating marching towards the northwest Asia monsoon region from June to August. The march of convection

  7. Inorganic compounds for passive solar energy storage: Solid-state dehydration materials and high specific heat materials

    NASA Astrophysics Data System (ADS)

    Struble, L. J.; Brown, P. W.

    1986-04-01

    Two classes of hydrated inorganic salts have been studied to assess their potential as materials for passive solar energy storage. The materials are part of the quaternary system CaO-Al2O3-SO3-H2O and related chemical systems, and the two classes are typified by ettringite, a trisubstituted salt, and Friedel's salt, a monosubstituted salt. The trisubstituted salts were studied for their possible application in latent heat storage, utilizing a low-temperature dehydration reaction, and both classes were studies for their application in sensible heat storage. In order to assess their potential for energy storage, the salts have been synthesized, characterized by several analytical techniques, and thermal properties measured. The dehydration data of that the trisubstituted salts vary somewhat with chemical composition, with the temperature of the onset of dehydration ranging from 6(0)C to 33(0)C, and enthalpy changes on dehydration ranging from 60 to 200 cal/g. Heat capacity is less variable with composition; values for the trisubstituted phases are 30 cal/g/(0)C and for the monosubstituted phases between 0.23 and 0.28 cal/g/(0)C. Preliminary experiments indicate that the dehydration is reversible, and suggest that the materials might have additional potential as solar desiccant materials. These thermal data demonstrate the trisubstituted salts have potential as latent heat storage materials, and that both classes of salts have potential as sensible heat storage materials.

  8. Chronic recurrent dehydration associated with periodic water intake exacerbates hypertension and promotes renal damage in male spontaneously hypertensive rats

    PubMed Central

    Hilliard, Lucinda M.; Colafella, Katrina M. Mirabito; Bulmer, Louise L.; Puelles, Victor G.; Singh, Reetu R.; Ow, Connie P. C.; Gaspari, Tracey; Drummond, Grant R.; Evans, Roger G.; Vinh, Antony; Denton, Kate M.

    2016-01-01

    Epidemiological evidence links recurrent dehydration associated with periodic water intake with chronic kidney disease (CKD). However, minimal attention has been paid to the long-term impact of periodic water intake on the progression of CKD and underlying mechanisms involved. Therefore we investigated the chronic effects of recurrent dehydration associated with periodic water restriction on arterial pressure and kidney function and morphology in male spontaneously hypertensive rats (SHR). Arterial pressure increased and glomerular filtration rate decreased in water-restricted SHR. This was observed in association with cyclic changes in urine osmolarity, indicative of recurrent dehydration. Additionally, water-restricted SHR demonstrated greater renal fibrosis and an imbalance in favour of pro-inflammatory cytokine-producing renal T cells compared to their control counterparts. Furthermore, urinary NGAL levels were greater in water-restricted than control SHR. Taken together, our results provide significant evidence that recurrent dehydration associated with chronic periodic drinking hastens the progression of CKD and hypertension, and suggest a potential role for repetitive bouts of acute renal injury driving renal inflammatory processes in this setting. Further studies are required to elucidate the specific pathways that drive the progression of recurrent dehydration-induced kidney disease. PMID:27653548

  9. Serotonin modulates the dehydration-induced changes in tolerance for bitter water.

    PubMed

    Iwai, Masaki; Muroi, Yoshikage; Kinoshita, Ken-ichi; Ishii, Toshiaki

    2015-11-01

    Drinking behavior is regulated by endogenous factors such as the hydration condition of animals and exogenous factors such as the taste of ingested fluids. These factors have been suggested to interact with each other via serotonergic (5-HT) signaling to regulate drinking behavior. In the present study, we examined how dehydration affects the intake of bitter water, which suppresses drinking behavior, via 5-HT signaling. Water deprivation increased water intake for 1h, depending on the duration of water deprivation. The intake of 1mM quinine, which is a bitter tastant, was lower than that of water in mice deprived of water for 24h but not 48 h. We next examined the involvement of the dorsal raphe nucleus (DRN) and median raphe nucleus (MRN), which contain a large population of 5-HT neurons, in changing tolerance for quinine intake after water deprivation. The intake of quinine following water deprivation for 24h, but not 48 h, increased the number of tryptophan hydroxylase-positive neurons expressing c-Fos in the DRN, but not in the MRN. Moreover, administration of paroxetine, a selective serotonin reuptake inhibitor, decreased the intake of quinine solution, but not water, in mice deprived of water for 48 h, indicating that paroxetine treatment restored the aversion to quinine. These results suggest that unresponsiveness of 5-HT neurons in the DRN may be involved in the dehydration-induced increase in tolerance for bitter water.

  10. Pressure dependence of ionic conductivity of hydrated and dehydrated zeolites A

    NASA Astrophysics Data System (ADS)

    Goryainov, S. V.; Secco, R. A.; Huang, Y.; Liu, H.

    2007-03-01

    Hydrated and dehydrated zeolites MA (where M=Li, Na and K) with LTA structure have been studied by impedance spectroscopy with scanning frequency from 1 Hz to 1 MHz at high pressure up to 4.5 GPa and high temperature up to 250 °C. Anomalous increase in electrical AC conductivity at about 1.5-2 GPa observed in hydrated zeolites is associated with changes in crystalline structure leading to the formation of high-diffusion state of cation and water stuffing of the channels. In dehydrated zeolites, electrical conductivity is controlled by diffusion of cations (Li +, Na + and K +), which is determined by cation sites and aluminosilicate ring windows. LiA and NaA zeolites show normal decrease of conductivity with pressure, whereas KA zeolite exhibits the anomalous dependence with considerable increase and then fast decrease of conductivity. The behaviour of KA zeolite is associated with nearly central location of cation site in 8-membered ring, different from that in LiA and NaA zeolites.

  11. Effect of dehydration on hypothalamic control of evaporation in the cat.

    PubMed Central

    Baker, M A; Doris, P A

    1982-01-01

    1. Cats were surgically prepared with intracranial thermodes for heating of the hypothalamic thermosensitive area or with venous cannulae for measurement of blood volume and plasma osmolality. They were kept in an environmental chamber in which the ambient temperature was cycled between 25 and 38 degrees C on an 18:6 hr diurnal schedule. 2. Measurements of blood volume and plasma osmolality and of the evaporative response to hypothalamic heating were made during the 38 degrees C phase of the diurnal temperature cycle in animals when they were hydrated ad lib and in the same animals after 72--96 hr of water deprivation. 3. Water deprivation produced a loss of 10% of the body weight, a significant rise in plasma osmolality and a significant fall in blood volume. 4. Hypothalamic heating in hydrated animals generated a highly significant, positive, linear relationship between hypothalamic temperature and evaporative heat loss in every case. 5. In dehydrated animals, the evaporative response to hypothalamic heating was reduced. Rates of evaporation at a given hypothalamic temperature were lower and the slopes of the lines relating evaporative heat loss to hypothalamic temperature were significantly reduced. 6. It is concluded that dehydration reduces the thermal responsiveness of central neural structures controlling evaporation in the cat. PMID:7069627

  12. In situ dehydration of carbamazepine dihydrate: a novel technique to prepare amorphous anhydrous carbamazepine.

    PubMed

    Li, Y; Han, J; Zhang, G G; Grant, D J; Suryanarayanan, R

    2000-01-01

    The purposes of this project were to prepare amorphous carbamazepine by dehydration of crystalline carbamazepine dihydrate, and to study the kinetics of crystallization of the prepared amorphous phase. Amorphous carbamazepine was formed and characterized in situ in the sample chamber of a differential scanning calorimeter (DSC), a thermogravimetric analyzer (TGA), and a variable temperature x-ray powder diffractometer (VTXRD). It has a glass transition temperature of 56 degrees C and it is a relatively strong glass with a strength parameter of 37. The kinetics of its crystallization were followed by isothermal XRD, under a controlled water vapor pressure of 23 Torr. The crystallization kinetics are best described by the three-dimensional nuclear growth model with rate constants of 0.014, 0.021, and 0.032 min-1 at 45, 50, and 55 degrees C, respectively. When the Arrhenius equation was used, the activation energy of crystallization was calculated to be 74 kJ/mol in the presence of water vapor (23 Torr). On the basis of the Kissinger plot, the activation energy of crystallization in the absence of water vapor (0 Torr water vapor pressure) was determined to be 157 kJ/mol. Dehydration of the dihydrate is a novel method to prepare amorphous carbamazepine; in comparison with other methods, it is a relatively gentle and effective technique.

  13. Cryopreservation of Pistacia spp. seeds by dehydration and one-step freezing.

    PubMed

    Ozden-Tokatli, Y; Ozudogru, E A; Gumusel, F; Lambardi, M

    2007-01-01

    Cryopreservation protocols by dehydration and one-step freezing were developed for seeds from three Pistacia species, i.e., P. vera, P. terebinthus and P. lentiscus, which were characterised by different initial germination percentages (100%, 17% and 81%, respectively). In P. vera, a maximum of 90% germination was obtained following 8 hours drying in silica gel (corresponding to 11.7% moisture content on a FW basis) and direct immersion in LN. In P. terebinthus and P. lentiscus, shorter periods of dehydration (1 hour and 15 min, respectively) were sufficient to reduce their moisture content to about 20%, which resulted in peak seed germination percentages from cryostorage of 16% and 47%, respectively. Following cryopreservation, the seeds germinated better on semi-solid MS medium, than on cotton wool wetted with dH(2)O or liquid MS medium. Finally, in P. vera and P. lentiscus, high and significant correlation coefficients were obtained between the TTC viability test and seed germinability after recovery from LN, provided that seeds which were considered positive in the test showed completely or partially red embryonic axes coupled to completely red cotyledons.

  14. Dehydration in the lower Antarctic stratosphere during late winter and early spring, 1987

    NASA Technical Reports Server (NTRS)

    Kelly, K. K.; Tuck, A. F.; Murphy, D. M.; Fahey, D. W.; Proffitt, M. H.; Jones, R. L.; Mckenna, D. S.; Loewenstein, M.; Podolske, J. P.; Strahan, S. E.

    1989-01-01

    The history of minimum temperatures at 50 and 70 mb is examined from NMC, UK Met O and ECMWF analyses. MSU channel 24 data are similarly inspected. South Pole sonde data are used to calculate saturation humidity mixing ratio as a function of altitude and time throughout 1987. Saturation with respect to ice could be maintained for water mixing ratios of 3.5 ppmv for a period of about 80 days from mid-June to mid-September. Dehydration to mixing ratios of 1 ppmv or less was possible sporadically. Data from the ER-2 flights between 53 S and 72 S are used in conjunction with particle size measurements and air parcel trajectories to demonstrate the dehydration occurring over Antarctica. Water mixing ratios at the latitude of Punta Arens (53 S), in conjunction with tracer measurements and trajectory analysis, show that at potential temperatures from about 325 to 400 K, the dryness (less than 3 ppmv) had its origin over Antarctica rather than in the tropics. Water mixing ratios within the Antarctic vortex varied from 1.5 to 3.8 ppmv, with a strong isentropic gradient being evident in the region of high potential vorticity gradients.

  15. Dehydration in the lower Antarctic stratosphere in late winter and spring

    NASA Technical Reports Server (NTRS)

    Kelly, K. K.; Tuck, A. F.; Fahey, D. W.; Proffitt, M. H.; Murphy, D. M.; Jones, R. L.; Mckenna, D. S.; Heidt, L. E.; Ferry, G. V.; Loewenstein, M.

    1988-01-01

    The history of minimum temperatures at 50 and 70 mb is examined from NMC, UK Met 0 and ECMWF analyses. MSU channel 24 data are similarly inspected. South Pole sonde data are used to calculate saturation humidity mixing ratio as a function of altitude and time throughout 1987. Saturation with respect to ice could be maintained for water mixing ratios of 3.5 ppmv for a period of about 80 days from mid-June to mid-September. Dehydration to mixing ratios of 1 ppmv or less was possible sporadically. Data from the ER-2 flights between 53 S and 72 S are used in conjunction with particle size measurements and air parcel trajectories to demonstrate the dehydration occurring over Antarctica. Water mixing ratios at the latitude of Punta Arenas (53 S), in conjunction with tracer measurements and trajectory analysis, show that at potential temperatures from about 325 to 400 K, the dryness (less than 3 ppmv) had its origin over Antarctica rather than in the tropics. Water mixing ratios within the Antarctic vortex varied from 1.5 to 3.8 ppmv, with a strong isentropic gradient being evident in the region of high potential vorticity gradients.

  16. The January 30, 1989 Arctic polar stratospheric clouds (PSC) event - Evidence for a mechanism of dehydration

    NASA Technical Reports Server (NTRS)

    Gandrud, B. W.; Dye, J. E.; Baumgardner, D.; Ferry, G. V.; Loewenstein, M.; Chan, K. R.; Sanford, L.; Gary, B.

    1990-01-01

    In-situ particle measurements made aboard the NASA ER-2 in the Arctic on 890130 (YYMMDD) show Type 1 PSC particles over much of the flight, with instances of embedded Type 2 PSCs. The Type 2 particles were observed at temperatures warmer than the local frost-point temperature of water; extended up to the upper size cutoff of the instrument (about 24-micron diameter); and are shown to contain too large a volume to be primarily NAT. Based on measured vertical temperature profiles, it is concluded that the Type 2 particles observed on this day were formed above the aircraft in a region where saturation with respect to ice was achieved and were sufficiently large to have fallen into the path of the ER-2. Although the amount of material in the particles, expressed as water, is small by comparison to the total (vapor + aerosol) water concentration, the flux of water from the falling particles is of sufficient magnitude, if sustained, to lead to dehydration of the source region. These observations verify the mechanism for dehydration of polar vortex air masses by precipitation of ice particles.

  17. Dehydration of xylose to furfural over MCM-41-supported niobium-oxide catalysts.

    PubMed

    García-Sancho, Cristina; Sádaba, Irantzu; Moreno-Tost, Ramón; Mérida-Robles, Josefa; Santamaría-González, José; López-Granados, Manuel; Maireles-Torres, Pedro

    2013-04-01

    A series of silica-based MCM-41-supported niobium-oxide catalysts are prepared, characterized by using XRD, N2 adsorption-desorption, X-ray photoelectron spectroscopy, Raman spectroscopy, and pyridine adsorption coupled to FTIR spectroscopy, and tested for the dehydration of D-xylose to furfural. Under the operating conditions used all materials are active in the dehydration of xylose to furfural (excluding the MCM-41 silica support). The xylose conversion increases with increasing Nb2 O5 content. At a loading of 16 wt % Nb2 O5 , 74.5 % conversion and a furfural yield of 36.5 % is achieved at 170 °C, after 180 min reaction time. Moreover, xylose conversion and furfural yield increase with the reaction time and temperature, attaining 82.8 and 46.2 %, respectively, at 190 °C and after 100 min reaction time. Notably, the presence of NaCl in the reaction medium further increases the furfural yield (59.9 % at 170 °C after 180 min reaction time). Moreover, catalyst reutilization is demonstrated by performing at least three runs with no loss of catalytic activity and without the requirement for an intermediate regeneration step. No significant niobium leaching is observed, and a relationship between the structure of the catalyst and the activity is proposed.

  18. Putrescine accumulation in Arabidopsis thaliana transgenic lines enhances tolerance to dehydration and freezing stress

    PubMed Central

    Alet, Analía I; Sanchez, Diego H; Cuevas, Juan C; del Valle, Secundino; Altabella, Teresa; Tiburcio, Antonio F; Marco, Francisco; Ferrando, Alejandro; Espasandín, Fabiana D; González, María E; Carrasco, Pedro

    2011-01-01

    Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, ADC; EC 4.1.1.19) are more sensitive than the wild type to this stress. Although it is speculated that the overexpression of ADC genes may confer tolerance, this is hampered by pleiotropic effects arising from the constitutive expression of enzymes from the polyamine metabolism. Here, we present our work using A. thaliana transgenic plants harboring the ADC gene from oat under the control of a stress-inducible promoter (pRD29A) instead of a constitutive promoter. The transgenic lines presented in this work were more resistant to both cold and dehydration stresses, associated with a concomitant increment in endogenous putrescine levels under stress. Furthermore, the increment in putrescine upon cold treatment correlates with the induction of known stress-responsive genes, and suggests that putrescine may be directly or indirectly involved in ABA metabolism and gene expression. PMID:21330789

  19. Evolution of nanostructure and specific surface area during thermally driven dehydration of Mg(OH)2

    NASA Astrophysics Data System (ADS)

    Pimminger, H.; Habler, G.; Freiberger, N.; Abart, R.

    2016-01-01

    The thermally induced dehydration of micrometer-sized particles of Mg(OH)2 was investigated experimentally at ambient pressure and temperatures ranging from 350 to 1300 °C. Reaction progress is correlated with the evolution of the specific surface area and of the particle internal nanostructure. The maximum specific surface area of about 320 m2/g corresponding to a 70-fold increase relative to the starting material is obtained after heat treatment at 350 °C for about 2 h. This is due to the formation of a highly porous, particle-internal nanostructure comprised of newly crystallized strictly aligned, cube-shaped and nanometer-sized crystals of MgO and about 50 vol% porosity. Associated with the dehydration, intensive fracturing and defoliation occurs parallel to the (0001) plane of the original Mg(OH)2 or (111) of the topotaxially grown MgO. After heat treatment at increasingly higher temperatures, enhanced coarsening and sintering of the MgO crystals and healing of cracks leads to a successive decrease of the specific surface area. After heat treatment at 1300 °C for 2.5 h, the specific surface area has decreased to 5 m2/g close to the value typical for the original Mg(OH)2.

  20. Measurement of the equilibrium relative humidity for common precipitant concentrations: facilitating controlled dehydration experiments

    PubMed Central

    Wheeler, Matthew J.; Russi, Silvia; Bowler, Michael G.; Bowler, Matthew W.

    2012-01-01

    The dehydration of crystals of macromolecules has long been known to have the potential to increase their diffraction quality. A number of methods exist to change the relative humidity that surrounds crystals, but for reproducible results, with complete characterization of the changes induced, a precise humidity-control device coupled with an X-ray source is required. The first step in these experiments is to define the relative humidity in equilibrium with the mother liquor of the system under study; this can often be quite time-consuming. In order to reduce the time spent on this stage of the experiment, the equilibrium relative humidity for a range of concentrations of the most commonly used precipitants has been measured. The relationship between the precipitant solution and equilibrium relative humidity is explained by Raoult’s law for the equilibrium vapour pressure of water above a solution. The results also have implications for the choice of cryoprotectant and solutions used to dehydrate crystals. For the most commonly used precipitants (10–30% PEG 2000–8000), the starting point will be a relative humidity of 99.5%. PMID:22232186

  1. [Effect of a dehydrated extract of nopal (Opuntia ficus indica Mill.) on blood glucose].

    PubMed

    Frati-Munari, A C; de León, C; Ariza-Andraca, R; Bañales-Ham, M B; López-Ledesma, R; Lozoya, X

    1989-01-01

    To assess if a dehydrated extract of nopal stems retains the effect on glycemia of the entire nopal stems two experiments were performed. A. Six patients with type II diabetes mellitus in fasting condition received 30 capsules containing 10.1 +/- 0.3 g of the extract, and serum glucose levels were measured hourly from 0 to 180 minutes. B. Six healthy volunteers received 30 capsules with the extract followed by 74 g of dextrose orally. Serum glucose measurements were made in a similar fashion. In each experiment a control test with empty capsules was performed. Nopal extract did not reduce fasting glycemia in diabetic subjects. Nevertheless, the extract diminished the increase of serum glucose which followed a dextrose load. Peak serum glucose was 20.3 +/- 18.2 mg/dl (X +/- SD) lower in the test with nopal than in the control one (P less than 0.025). Dehydrated extract of nopal (Opuntia ficus-indica Mill) did not show acute hypoglycemic effect, although could attenuate postprandial hyperglycemia.

  2. Studies on Osmo-air dehydration of different Indian apricot (Prunus armeniaca L.) cultivars.

    PubMed

    Raj, Dev; Sharma, P C; Sharera, Sanjay K

    2015-06-01

    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 were preferred over whole fruits with stones with respect to appearance, texture and overall acceptability. Among different cultivars of apricot; cv. Kaisha followed by New Castle were found better with respect to yield as well as quality of dried product. Further, the quality of the osmo-air dried wild apricot fruits was found statistically at par with the quality of the osmo-air dried product obtained from cultivated apricots. Therefore, wild apricot fruits can also be utilized for preparation of acceptable quality of dried product.

  3. NMR studies of renal phosphate metabolites in vivo: Effects of hydration and dehydration

    SciTech Connect

    Wolff, S.D.; Eng, C.; Balaban, R.S. )

    1988-10-01

    The present study characterizes the {sup 31}P-nuclear magnetic resonance (NMR) spectrum of rabbit kidneys in vivo and evaluates the effect of hydration on phosphorous metabolites including the organic solute glycerophosphorylcholine (GPC). Cortical phosphorylethanolamine is the predominant component of the phosphomonoester region of the {sup 31}P spectrum. The contribution of blood to the spectrum is mainly from 2,3 diphosphoglycerate, which comprises {approximately}30% of the inorganic phosphate region. Acute infusion of 0.9% saline decreases the sodium content of the inner medulla by >50% in 15 min as shown by {sup 23}Na imaging. Despite this medullary Na dilution, no change in renal GPC content was observed for >1 h even with the addition of furosemide or furosemide and antidiuretic hormone. However, 20 h of chronic dehydration with 0.45% saline did result in a 30% decrease in renal GPC content when compared with dehydrated animals. These findings are consistent with GPC not playing a role in the short-term regulation of the medullary intracellular milieu in response to acute reductions in medullary Na content.

  4. Three-dimensional numerical modeling of thermal regime and slab dehydration beneath Kanto and Tohoku, Japan

    NASA Astrophysics Data System (ADS)

    Ji, Yingfeng; Yoshioka, Shoichi; Manea, Vlad Constantin; Manea, Marina; Matsumoto, Takumi

    2017-01-01

    Although the thermal regime of the interface between two overlapping subducting plates, such as those beneath Kanto, Japan, is thought to play an important role in affecting the distribution of interplate and intraslab earthquakes, the estimation of the thermal regime remains challenging to date. We constructed a three-dimensional (3-D) thermal convection model to simulate the subduction of the Pacific plate along the Japan Trench and Izu-Bonin Trench, including the subduction of the Philippine Sea beneath Kanto and investigated the slab thermal regime and slab water contents in this complex tectonic setting. Based on the subduction parameters tested in generic models with two flat oceanic plates, a faster or thicker plate subducting in a more trench-normal direction produces a colder slab thermal regime. The interplate temperature of the cold anomaly beneath offshore Kanto was approximately 300°C colder than that beneath offshore Tohoku at a same depth of 40 km and approximately 600°C colder at a depth of 70 km. The convergence between the two subducting plates produces an asymmetric thermal structure in the slab contact zone beneath Kanto, which is characterized by clustered seismicity in the colder southwestern half. The thermo-dehydration state of the mid-ocean ridge basalt near the upper surface of the subducted Pacific plate controls the interplate seismicity beneath the Kanto-Tohoku region according to the spatial concurrence of the thermo-dehydration and seismicity along the megathrust fault zone of the subducted Pacific plate.

  5. Effect of ultrasound treatment on the water state in kiwifruit during osmotic dehydration.

    PubMed

    Nowacka, M; Tylewicz, U; Laghi, L; Dalla Rosa, M; Witrowa-Rajchert, D

    2014-02-01

    The present work investigates how ultrasound pretreatment modulates the effects of osmotic dehydration (OD) on the water state and microstructure of kiwifruit. Kiwifruit slices (10mm thick) were subjected to ultrasonic waves in a water bath at a frequency of 35 kHz for 10, 20 and 30 min. OD process was then carried out by immersing the samples in 61.5% sucrose solution equilibrated at 25°C for a contact period of 0, 10, 20, 30, 60 and 120 min. The partition of water into the cellular tissue structures (vacuole, cytoplasm, extracellular spaces and cell wall) was investigated by Time Domain Nuclear Magnetic Resonance (TD-NMR). In parallel, the microstructure of kiwifruits slices was examined using a Scanning Electron Microscope. The results showed that US pretreatment performed for more than 10 min had a positive effect on the mass exchange caused by osmotic dehydration. A creation of microchannels and an increase of the average cross-section area of cells were observed when the samples were pretreated with US before OD. TD-NMR showed a slight redistribution of water through the substructures of the cells, as a function of the length of the US pretreatment applied.

  6. Putrescine accumulation in Arabidopsis thaliana transgenic lines enhances tolerance to dehydration and freezing stress.

    PubMed

    Alet, Analía I; Sanchez, Diego H; Cuevas, Juan C; Del Valle, Secundino; Altabella, Teresa; Tiburcio, Antonio F; Marco, Francisco; Ferrando, Alejandro; Espasandín, Fabiana D; González, María E; Ruiz, Oscar A; Carrasco, Pedro

    2011-02-01

    Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, ADC; EC 4.1.1.19) are more sensitive than the wild type to this stress. Although it is speculated that the over-expression of ADC genes may confer tolerance, this is hampered by pleiotropic effects arising from the constitutive expression of enzymes from the polyamine metabolism. Here, we present our work using A. thaliana transgenic plants harboring the ADC gene from oat under the control of a stress-inducible promoter (pRD29A) instead of a constitutive promoter. The transgenic lines presented in this work were more resistant to both cold and dehydration stresses, associated with a concomitant increment in endogenous putrescine levels under stress. Furthermore, the increment in putrescine upon cold treatment correlated with the induction of known stress-responsive genes, and suggested that putrescine may be directly or indirectly involved in ABA metabolism and gene expression.

  7. The importance of dehydration in determining ion transport in narrow pores.

    PubMed

    Richards, Laura A; Schäfer, Andrea I; Richards, Bryce S; Corry, Ben

    2012-06-11

    The transport of hydrated ions through narrow pores is important for a number of processes such as the desalination and filtration of water and the conductance of ions through biological channels. Here, molecular dynamics simulations are used to systematically examine the transport of anionic drinking water contaminants (fluoride, chloride, nitrate, and nitrite) through pores ranging in effective radius from 2.8 to 6.5 Å to elucidate the role of hydration in excluding these species during nanofiltration. Bulk hydration properties (hydrated size and coordination number) are determined for comparison with the situations inside the pores. Free energy profiles for ion transport through the pores show energy barriers depend on pore size, ion type, and membrane surface charge and that the selectivity sequence can change depending on the pore size. Ion coordination numbers along the trajectory showed that partial dehydration of the transported ion is the main contribution to the energy barriers. Ion transport is greatly hindered when the effective pore radius is smaller than the hydrated radius, as the ion has to lose some associated water molecules to enter the pore. Small energy barriers are still observed when pore sizes are larger than the hydrated radius due to re-orientation of the hydration shell or the loss of more distant water. These results demonstrate the importance of ion dehydration in transport through narrow pores, which increases the current level of mechanistic understanding of membrane-based desalination and transport in biological channels.

  8. Slab melting beneath the Cascades Arc driven by dehydration of altered oceanic peridotite

    USGS Publications Warehouse

    Walowski, Kristina J; Wallace, Paul J.; Hauri, E.H.; Wada, I.; Clynne, Michael A.

    2015-01-01

    Water is returned to Earth’s interior at subduction zones. However, the processes and pathways by which water leaves the subducting plate and causes melting beneath volcanic arcs are complex; the source of the water—subducting sediment, altered oceanic crust, or hydrated mantle in the downgoing plate—is debated; and the role of slab temperature is unclear. Here we analyse the hydrogen-isotope and trace-element signature of melt inclusions in ash samples from the Cascade Arc, where young, hot lithosphere subducts. Comparing these data with published analyses, we find that fluids in the Cascade magmas are sourced from deeper parts of the subducting slab—hydrated mantle peridotite in the slab interior—compared with fluids in magmas from the Marianas Arc, where older, colder lithosphere subducts. We use geodynamic modelling to show that, in the hotter subduction zone, the upper crust of the subducting slab rapidly dehydrates at shallow depths. With continued subduction, fluids released from the deeper plate interior migrate into the dehydrated parts, causing those to melt. These melts in turn migrate into the overlying mantle wedge, where they trigger further melting. Our results provide a physical model to explain melting of the subducted plate and mass transfer from the slab to the mantle beneath arcs where relatively young oceanic lithosphere is subducted.

  9. Cirrus Clouds, Equatorial Kelvin Waves and Dehydration in the Tropical Tropopause Layer

    NASA Astrophysics Data System (ADS)

    Schrems, O.; Immler, F.; Krueger, K.; Rex, M.; Fujiwara, M.

    2007-12-01

    A number of field-campaigns in the tropics have been conducted in the past years with the mobile LIDAR systems MARL and ComCAL of the Alfred Wegener Institute aboard the research vessel Polarstern in the tropical Atlantic and at Paramaribo in Suriname. The lidars detect particles in the atmosphere with high vertical and temporal resolution and are capable of detecting extremely thin cloud layers which frequently occur in the tropical tropopause layer (TTL). We investigated the occurrence of clouds in the TTL with a newly developed trajectory model and found that ice particles form in slow ascent and efficiently dehydrate the air. The Lagrangian temperature history thus defines the water vapour transported to the stratosphere in the tropics. Radiosonde as well as ECMWF operational analysis data show a strong influence of eastward moving equatorial Kelvin waves on the temperature at the tropical cold point tropopause (CPT). We find a clear correlation between the temperature anomalies introduced by these waves and the occurrence of thin cirrus. This finding suggests an influence of Kelvin wave activity on the dehydration characteristics of the TTL

  10. The January 30, 1989 Arctic polar stratospheric clouds (PSC) event - Evidence for a mechanism of dehydration

    NASA Astrophysics Data System (ADS)

    Gandrud, B. W.; Dye, J. E.; Baumgardner, D.; Ferry, G. V.; Loewenstein, M.; Chan, K. R.; Sanford, L.; Gary, B.

    1990-03-01

    In-situ particle measurements made aboard the NASA ER-2 in the Arctic on 890130 (YYMMDD) show Type 1 PSC particles over much of the flight, with instances of embedded Type 2 PSCs. The Type 2 particles were observed at temperatures warmer than the local frost-point temperature of water; extended up to the upper size cutoff of the instrument (about 24-micron diameter); and are shown to contain too large a volume to be primarily NAT. Based on measured vertical temperature profiles, it is concluded that the Type 2 particles observed on this day were formed above the aircraft in a region where saturation with respect to ice was achieved and were sufficiently large to have fallen into the path of the ER-2. Although the amount of material in the particles, expressed as water, is small by comparison to the total (vapor + aerosol) water concentration, the flux of water from the falling particles is of sufficient magnitude, if sustained, to lead to dehydration of the source region. These observations verify the mechanism for dehydration of polar vortex air masses by precipitation of ice particles.

  11. Dehydration kinetics of salmon and trout fillets using ultrasonic vacuum drying as a novel technique.

    PubMed

    Başlar, Mehmet; Kılıçlı, Mahmut; Yalınkılıç, Barış

    2015-11-01

    In this study, a novel ultrasonic vacuum (USV) drying technique was used to shorten the drying time of fish fillets. For this purpose, ultrasonic treatment and vacuum-drying were simultaneously performed to dehydrate salmon and trout fillets at 55°C, 65°C, and 75°C. In addition, the USV technique was compared with vacuum-drying and oven-drying techniques. The dehydration kinetics of the fillets was successfully described by seven thin-layer drying models with R(2) range between 0.944 and 1.000. Depending on drying temperatures and fish species, the drying times could be shortened using the USV technique between 7.4% and 27.4% compared with vacuum-drying. The highest effective moisture diffusivity was determined in the fillets dried with the USV technique and they increased with increasing drying temperatures. Ultrasonic treatment accelerated the vacuum drying process for the fillets; therefore, this technique could be used to improve the efficiency of vacuum-drying for the fillets.

  12. Smart Contact Lenses with Graphene Coating for Electromagnetic Interference Shielding and Dehydration Protection.

    PubMed

    Lee, Sangkyu; Jo, Insu; Kang, Sangmin; Jang, Bongchul; Moon, Joonhee; Park, Jong Bo; Lee, Soochang; Rho, Sichul; Kim, Youngsoo; Hong, Byung Hee

    2017-02-21

    Recently, smart contact lenses with electronic circuits have been proposed for various sensor and display applications where the use of flexible and biologically stable electrode materials is essential. Graphene is an atomically thin carbon material with a two-dimensional hexagonal lattice that shows outstanding electrical and mechanical properties as well as excellent biocompatibility. In addition, graphene is capable of protecting eyes from electromagnectic (EM) waves that may cause eye diseases such as cataracts. Here, we report a graphene-based highly conducting contact lens platform that reduces the exposure to EM waves and dehydration. The sheet resistance of the graphene on the contact lens is as low as 593 Ω/sq (±9.3%), which persists in an wet environment. The EM wave shielding function of the graphene-coated contact lens was tested on egg whites exposed to strong EM waves inside a microwave oven. The results show that the EM energy is absorbed by graphene and dissipated in the form of thermal radiation so that the damage on the egg whites can be minimized. We also demonstrated the enhanced dehydration protection effect of the graphene-coated lens by monitoring the change in water evaporation rate from the vial capped with the contact lens. Thus, we believe that the graphene-coated contact lens would provide a healthcare and bionic platform for wearable technologies in the future.

  13. Effect of temperature and cultivar on polyphenol retention and mass transfer during osmotic dehydration of apples.

    PubMed

    Devic, Emilie; Guyot, Sylvain; Daudin, Jean-Dominique; Bonazzi, Catherine

    2010-01-13

    Several cultivars of apples (Malus domestica) were chosen for their variable concentrations and compositions in phenolic compounds. Cubed samples (1 cm3) were subjected to osmotic dehydration, and the effect of temperature was studied at 45 and 60 degrees C. Water loss, sucrose impregnation, and the evolution of some natural components of the product were followed to quantify mass transfer. Ascorbic acid and polyphenols were quantified by HPLC for several osmotic dehydration times and regardless of the quantity of impregnated sugar. Changes in antioxidant components differed as a function of the nature of molecules. Their concentrations decreased in line with temperature, and few differences were observed between cultivars. Processing at a lower temperature (45 degrees C) caused a total loss in ascorbic acid but allowed the retention of between 74 and 85% of initial polyphenols, depending on the cultivar. Cultivars containing highly polymerized procyanidins (such as Guillevic) experienced less loss. Hydroxycinnamic acids and monomeric catechins displayed the most marked changes. Leaching with water into the soaking solution was the principal mechanism retained to explain these losses.

  14. Prevention of cartilage dehydration in imaging studies with a customized humidity chamber

    NASA Astrophysics Data System (ADS)

    Choo, Ryan J.; Firminger, Colin; Müller, Ralph; Stok, Kathryn S.

    2013-09-01

    Quantitative three-dimensional imaging methods such as micro-computed tomography (μCT) allow for the rapid and comprehensive evaluation of cartilage and bone in animal models, which can be used for drug development and related research in arthritis. However, when imaging fresh cartilage tissue in air, a common problem is tissue dehydration which causes movement artifact in the resulting images. These artifacts distort scans and can render them unusable, leading to a considerable loss of time and effort with sample preparation and measurement. The sample itself is also irretrievably damaged by the dehydration, often unable to return to its full tissue thickness upon rehydration. Additionally, imaging with ionic contrast agents such as HexabrixTM must be performed in air, otherwise the agent will be washed out if immersed in a liquid. The first goal of this study was to design a customized humidity chamber to maintain cartilage hydration without the need for immersion. Following this, the use of the humidity chamber during a synchrotron radiation-μCT scan was validated and its performance evaluated. Results showed that the loss of fluid film volume is associated with scanning at low humidity (87%), and can be avoided using the humidity chamber. Coupling this technology with advances in synchrotron imaging (e.g., phase contrast imaging) or contrast agents is promising.

  15. Oxidation-induced calcium-dependent dehydration of normal human red blood cells.

    PubMed

    Shcherbachenko, Irina M; Lisovskaya, Irina L; Tikhonov, Vladimir P

    2007-05-01

    Phenazine-methosulphate (PMS) is a strong oxidant that induces reactive oxygen species (ROS) formation in cells. Though it has been shown that PMS increases the red blood cell (RBC) membrane permeability to K(+), the hypotheses on the mechanism of PMS-induced effects are contradictory and there are no data on volume changes induced by this oxidant. Therefore, the influence of the PMS + ascorbate oxidative system on the volume of normal human RBCs was studied. In a Ca(2 + )-containing medium, PMS + ascorbate caused dehydration (shrinking) of RBCs judged by: (1) changes in the density and osmotic resistance distributions of RBCs, and (2) a decrease in their low-angle scattering assessed by FACS analysis. The dehydration resulted from activation of the Gardos channels, was PMS and ascorbate concentration-dependent, was associated with broadening of the density and osmotic resistance distributions of the RBCs, and decreased in the presence of the taxifolin and rutin antioxidants. These findings contribute to a better understanding of the physiology and pathology of oxidatively-modified RBCs and may be of practical significance in estimating the antioxidant activity of various substances.

  16. Mantle wedge infiltrated with saline fluids from dehydration and decarbonation of subducting slab

    PubMed Central

    Kawamoto, Tatsuhiko; Yoshikawa, Masako; Kumagai, Yoshitaka; Mirabueno, Ma. Hannah T.; Okuno, Mitsuru; Kobayashi, Tetsuo

    2013-01-01

    Slab-derived fluids play an important role in heat and material transfer in subduction zones. Dehydration and decarbonation reactions of minerals in the subducting slab have been investigated using phase equilibria and modeling of fluid flow. Nevertheless, direct observations of the fluid chemistry and pressure–temperature conditions of fluids are few. This report describes CO2-bearing saline fluid inclusions in spinel-harzburgite xenoliths collected from the 1991 Pinatubo pumice deposits. The fluid inclusions are filled with saline solutions with 5.1 ± 1.0% (wt) NaCl-equivalent magnesite crystals, CO2-bearing vapor bubbles, and a talc and/or chrysotile layer on the walls. The xenoliths contain tremolite amphibole, which is stable in temperatures lower than 830 °C at the uppermost mantle. The Pinatubo volcano is located at the volcanic front of the Luzon arc associated with subduction of warm oceanic plate. The present observation suggests hydration of forearc mantle and the uppermost mantle by slab-derived CO2-bearing saline fluids. Dehydration and decarbonation take place, and seawater-like saline fluids migrate from the subducting slab to the mantle wedge. The presence of saline fluids is important because they can dissolve more metals than pure H2O and affect the chemical evolution of the mantle wedge. PMID:23716664

  17. Assessment of the remineralization in simulated enamel lesions via dehydration with near-IR reflectance imaging

    NASA Astrophysics Data System (ADS)

    Lee, Robert C.; Darling, Cynthia L.; Fried, Daniel

    2015-02-01

    Previous studies have demonstrated that near-IR imaging can be used to nondestructively monitor the severity of enamel lesions. Arrested lesions typically have a highly mineralized surface layer that reduces permeability and limits diffusion into the lesion. The purpose of this study was to investigate whether the rate of water loss correlates with the degree of remineralization using near-IR reflectance imaging. Artificial bovine (n=15) enamel lesions were prepared by immersion in a demineralization solution for 24 hours and they were subsequently placed in an acidic remineralization solution for different periods. The samples were dehydrated using an air spray for 30 seconds and surfaces were imaged using an InGaAs camera at 1300-1700 nm wavelengths. Near-IR reflectance intensity differences before and after dehydration decreased with longer periods of remineralization. This study demonstrated that near-IR reflectance imaging was suitable for the detection of remineralization in simulated caries lesions and near-IR wavelengths longer than 1400 nm are well suited for the assessment of remineralization.

  18. Dehydration of Glycerin to Acrolein Over Heteropolyacid Nano-Catalysts Supported on Silica-Alumina.

    PubMed

    Kang, Tae Hun; Choi, Jung Ho; Choi, Jun Seon; Song, In Kyu

    2015-10-01

    A series of H3PW12O40 nano-catalysts supported on silica-alumina (XH3PW12O40/SA (X = 10, 15, 20, 25, and 30)) with different H3PW12O40 content (X, wt%) were prepared, and they were applied to the dehydration of glycerin to acrolein. The effect of H3PW12O40 content on the physicochemical properties and catalytic activities of XH3PW12O40/SA nano-catalysts was investigated. Surface area and pore volume of XH3PW12O40/SA catalysts decreased with increasing H3PW12O40 content. Formation of H3PW12O40 aggregates was observed in the catalysts with high H3PW12O40 loading. Brønsted acidity of the catalysts showed a volcano-shaped trend with respect to H3PW12O40 content. It was revealed that yield for acrolein increased with increasing Brønsted acidity of XH3PW12O40/SA catalysts. Brønsted acidity of XH3PW12O40/SA catalysts served as a crucial factor determining the catalytic performance in the dehydration of glycerin. Among the catalysts tested, 25H3PW12O40/SA catalyst with the largest Brønsted acidity showed the best catalytic performance.

  19. Antioxidant activity evaluation of new dosage forms as vehicles for dehydrated vegetables.

    PubMed

    Romero-de Soto, María Dolores; García-Salas, Patricia; Fernández-Arroyo, Salvador; Segura-Carretero, Antonio; Fernández-Campos, Francisco; Clares-Naveros, Beatriz

    2013-06-01

    A dehydrated vegetables mixture loaded in four pharmaceutical dosage forms as powder, effervescent granulate, sugar granulate and gumdrops were investigated for their antioxidant capacity using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging capacity assay, oxygen radical absorbance capacity assay and ferric reducing antioxidant potential assay. Total phenolic content of dehydrated vegetables powder mixture was also measured by the Folin-Ciocalteu method, so as to evaluate its contribution to their total antioxidant function. The effect of different temperatures on stability of these systems after 90 days storage was also evaluated. These formulations presented strong antioxidant properties and high phenolic content (279 mg gallic acid equivalent/g of sample) and thus could be potential rich sources of natural antioxidants. Antioxidant properties differed significantly among selected formulations (p < 0.05). Generally, the losses were lower in samples stored under refrigeration. To interpret the antioxidant properties a kinetic approach was performed. Degradation kinetics for the phenolic content and antioxidant capacity followed a zero-order function. Effervescent granulate was the formulation which underwent faster degradation. Contrary, sugar granulate and gumdrops were much more slowly. Time required to halve the initial amount of phenolic compounds was 589 ± 45 days for samples stored at 4 º C, and 312 ± 16 days for samples stored at room temperature. These developed dosage forms are new and innovative approach for vegetable intakes in population with special requirements providing an improvement in the administration of vegetables and fruits.

  20. Influence of menstrual status on fluid replacement after exercise induced dehydration in healthy young women.

    PubMed Central

    Maughan, R J; McArthur, M; Shirreffs, S M

    1996-01-01

    OBJECTIVE--To determine whether fluid replacement after exercise induced dehydration varies over the normal menstrual cycle. METHODS--Five subjects, with a regular menstrual cycle lasting 28 (SEM 2) d, were dehydrated by 1.8(0.1)% of their pre-exercise mass by cycle exercise in the heat. Trials were undertaken 2 d before (trial -2) and 5 and 19 d after the onset of menses (trials 6 and 20 respectively). After exercise, subjects ingested a fixed volume, equivalent to 150% of mass loss, of a commercially available sports drink over a 60 min period. RESULTS--Cumulative urine output [median (range)] over the 6 h following ingestion was the same on all trials: 714(469-750) ml on trial -2; 476(433-639) ml on trial 6; 534(195-852) ml on trial 20. There was no menstrual cycle effect on urinary electrolyte (Na+, K+, Cl-) excretion or serum electrolyte (Na+, K+, Cl-) concentrations. Plasma volume increased by 8-12% of the postexercise value following rehydration. The percentage of ingested fluid retained did not differ between trials at any time. Six hours after drink ingestion, net fluid balance was not different from the initial value on any of the trials. CONCLUSIONS--Acute replacement of exercise induced fluid losses is not affected by the normal menstrual cycle. PMID:8665117