Extent Of Dehydration Research Articles

Characterizing dehydration in short-term spaceflight using evidence from Project Mercury

Short-term spaceflight is commonly perceived as posing minimal risk to human health and performance. However, despite their duration, short-term flights potentially induce acute physiological changes that create risk to crews. One such change is dehydration (primarily body water loss) due to a heat-stressed environment. Such loss, if severe and prolonged, can lead to decrements in performance as well as increase the risk of more serious medical conditions. Though the general mechanisms of dehydration are broadly understood, the rate and extent of dehydration in short-term spaceflight has not been characterized. Combining data from the six spaceflights of the US Mercury program with a causal diagram illustrating the mechanisms of dehydration, we fit a path model to estimate the causal effects for all pathways in the causal model. Results demonstrate that Mercury astronauts experienced some degree of dehydration across the range of suited time and that the relationship between suited time and dehydration appears to be logarithmic. We discuss causal interpretations of the results and how the results from this and similar analyses can inform countermeasure development for short-term spaceflight.

Role of Fluid Resuscitation and Supportive Management of Diarrhea

The pediatric population is sensitive in every aspect. There are several parts of their bodies that need extreme levels of care and support until these children have reached a mature age. Similarly, there are several aspects of health that require immediate and urgent intervention, particularly in the pediatric population for better care and management. The reason behind this is the delicate and sensitive nature of the children’s health. Compromising any aspect of pediatric care might lead to severe consequences, which could be life-threatening too. Therefore, it is in the best interest of both the parents of the children and the physicians to be vigilant about the affected children’s symptoms just so they do not miss out on any important signs that could be transient or short-lived. Diarrhea is among the pediatric conditions that can very easily take a turn for the worse if it is not managed appropriately. Diarrhea can lead to severe consequences, including death in children, especially the malnourished ones. Diarrhea results in the excessive excretion of water, and electrolytes including sodium, potassium, bicarbonate, and zinc through watery stools. Dehydration ensues when these losses are not sufficiently replenished, leading to deficits in both water and electrolytes. The extent of dehydration is categorized based on symptoms and signs that mirror the quantity of fluid expelled. Depending upon these extents and degrees of dehydration, performing immediate resuscitation measures might be necessary. Among these measures, oral rehydration therapy is considered to be one of the most useful ones. It helps replenish the electrolytes rapidly and without causing any life-threatening consequences, especially when done within the specified time. On the brighter side, these fluid resuscitative measures might be the only interventions required to stop the child's progression further towards a severe form of the disease. This review is based on this fact only, and it revolves around the importance of performing fluid resuscitation and other elementary-level supportive measures that might be the only shot at saving the life of the child if done at an early stage. Thai review will help take action under the right circumstances if such a case arises in the clinical setting.

Freeze dehydration vs supercooling in tree stems: physical and physiological modelling.

Frost resistance is the major factor affecting the distribution of plant species at high latitude and elevation. The main effects of freeze-thaw cycles are damage to living cells and formation of gas embolism in tree xylem vessels. Lethal intracellular freezing can be prevented in living cells by two mechanisms, such as dehydration and deep supercooling. We developed a multiphysics numerical model coupling water flow, heat transfer and phase change, considering different cell types in plant tissues, to study the dynamics and extent of cell dehydration, xylem pressure changes and stem diameter changes in response to freezing and thawing. Results were validated using experimental data for stem diameter changes of walnut trees (Juglans regia). The effect of cell mechanical properties was found to be negligible as long as the intracellular tension developed during dehydration was sufficiently low compared with the ice-induced cryostatic suction. The model was finally used to explore the coupled effects of relevant physiological parameters (initial water and sugar content) and environmental conditions (air temperature variations) on the dynamics and extent of dehydration. It revealed configurations where cell dehydration could be sufficient to protect cells from intracellular freezing, and situations where supercooling was necessary. This model, freely available with this paper, could easily be extended to explore different anatomical structures, different species and more complex physical processes.

Cross‐disciplinary insights into the mechanisms of plant cold hardiness: From molecules to ecosystems

Cross‐disciplinary insights into the mechanisms of plant cold hardiness: From molecules to ecosystems

Comparing preservation substrates under field conditions for efficient DNA recovery in bone

Often bones are the only biological material left for the identification of human remains. As situations may occur where samples need to be stored for an extended period without access to cooling, appropriate storage of the bone samples is necessary for maintaining the integrity of DNA for profiling. To simulate DNA preservation under field conditions, pig rib bones were used to evaluate the effects of bone cleaning, buffer composition, storage temperature, and time on DNA recovery from bone samples. Bones were stored in three different buffers: TENT, solid sodium chloride, and ethanol-EDTA, at 20 °C and 35 °C for 10, 20, and 30 days. Bones were subsequently dried and ground to powder. DNA was extracted and quantified. Results show that temperature and storage time have no significant influence on DNA yield. DNA recovery from bones stored in solid sodium chloride or ethanol-EDTA was significantly higher compared to bones stored in TENT, and grinding of bones was facilitated by the extent of dehydration in solid sodium chloride and ethanol-EDTA compared to TENT. Overall, solid sodium chloride was found to be superior over ethanol-EDTA; when it comes to transportation, dry material such as salt eliminates the risk of leaking; it is non-toxic and in contrast to ethanol not classified as dangerous goods. Based on this study’s results, we recommend NaCl as a storage substrate for forensic samples in cases where no cooling/freezing conditions are available.

Control of Reactive Oxygen Species through Antioxidant Enzymes Plays a Pivotal Role during the Cultivation of Neopyropia yezoensis

Neopyropia yezoensis is an economically important marine crop that can survive dehydrating conditions when nets are lifted from seawater. During this process, production of oxygen radicals and the resulting up-regulation of antioxidant enzymes mediated by the abscisic acid (ABA) signaling pathway played an important role. However, there were no reports about the significance regarding the protection of seaweed throughout the entire production season. Especially, in new aquatic farms in Shandong Province that were formed when traditional N. yezoensis cultivation moved north. Here, we determined the levels of ABA, hydrogen peroxide (H2O2), soluble protein, chlorophyll, and cell wall polysaccharides in samples collected at different harvest periods from Jimo aquatic farm, Shandong Province. The activities and expression of NADPH oxidase (NOX) and antioxidant enzymes in the corresponding samples were also determined. Combined with the monitoring data of sea surface temperature and solar light intensity, we proposed that the cultivation of N. yezoensis in Shandong Province was not affected by high-temperature stress. However, photoinhibition in N. yezoensis usually occurs at noon, especially in March. Both the activities and the expression of NOX and antioxidant enzymes were up-regulated continuously. It is reasonable to speculate that the reactive oxygen species (ROS) produced by NOX induced the up-regulation of antioxidant enzymes through the ABA signaling pathway. Although antioxidant enzymes play a pivotal role during the cultivation of N. yezoensis, the production of ROS also caused a shift in gene expression, accumulation of secondary metabolites, and even decreased the chlorophyll pool size, which eventually led to a decrease in algae assimilation. Accordingly, we suggest that the dehydration of N. yezoensis nets should be adopted when necessary and the extent of dehydration should be paid special consideration to avoid an excessive cellular response caused by ROS.

Role of crystal water in luminescence properties of copper-doped hydronium alunite

Copper-doped hydronium alunite [(H3O)Al3(SO4)2(OH)6:Cu], a novel luminescent sulfate material, exhibiting blue luminescence was successfully synthesized under hydrothermal conditions. The originality of this luminescent material is such that the host crystal structure consists of crystal water (hydronium ions and hydroxyl radicals). Herein, we reported the results of a detailed investigation of changes in luminescence characteristics of the material with heat treatments. It was found that the material’s emission intensity was significantly reduced by heat treatment at temperatures ≥318 °C. The effect of varying amounts of copper and the extent of dehydration on the emission intensity was also investigated. As a result, a clear tendency was obtained that the luminescence intensity decreased as the weight loss increased due to dehydration. Thus, the presence of copper and crystal water are important factors affecting the luminescence of the material.

Dehydration as a possible tool to slow down peritoneal metastases by changing the intraperitoneal environment.

e16037 Background: Due to limited efficiency of current intravenous and intraperitoneal chemotherapeutic approaches, treating advanced peritoneal metastases (PM) remains an ongoing oncologic challenge. As the peritoneum is an optimal biological compartment for metastatic growth, stopping progressive tumor extension at more advanced stages is currently unachievable. With this study, we aim to investigate whether changing the intraperitoneal environment using dehydration might halt tumor progression. Methods: Commercially available human colon cancer cells (HT-29) were dehydrated for 15 minutes at 90% humidity and compared to cells treated with only oxaliplatin. Cell vitality was measured and structural cell changes following dehydration were analyzed via scanning electron microscopy. Additionally, staining with hematoxylin and eosin was performed on peritoneal tissue to assess dehydration effects using an ex vivo model. Finally, a mathematical model was established to measure dehydration of the abdominal compartment for feasibility evaluation. Results: Partial dehydration has a significant cytotoxic effect on colon cancer cells ( p< 0.05) even if only shortly applied. The addition of oxaliplatin treatment following dehydration results in highly reduced cell vitality ( p< 0.01). Sole dehydration vs. sole oxaliplatin application have similar effects. SEM revealed a cellular collapse of HT-29 cells caused by dehydration. Histopathological examination of peritoneal tissue demonstrated that the dehydration effect is superficial with penetration depths of < 200 µm. Conclusions: Our data indicate that dehydration is a potentially feasible technique with measurable cytotoxic effects on colorectal cancer cells. While changing the physiological milieu of the peritoneal cavity by means of dehydration could significantly reduce PM extent, the consequences of volume fluid loss must be equally considered. Thus, further studies are required to find a sustainable extent of dehydration while maintaining circulatory stability.

Stability of lyophilized albumin formulations: Role of excipient crystallinity and molecular mobility.

In freeze-dried protein formulations, the composition governs the physical forms of the excipients and hence their functionality. It is also necessary to understand the effect of composition on the molecular relaxation behavior, a key factor influencing protein stability. Mannitol (bulking agent) - trehalose (lyoprotectant) - bovine serum albumin (BSA) lyophiles with varying trehalose to BSA mass ratios were investigated. The crystalline phases were characterized by X-ray diffractometry. The secondary structure of albumin in lyophiles and reconstituted solutions was evaluated by IR spectroscopy and circular dichroism, respectively. Dielectric spectroscopy was used to obtain the relaxation time of freeze-dried samples. When trehalose to BSA ratio was 0.2, while mannitol crystallized predominantly as the δ-anhydrous polymorph, trehalose remained amorphous. At lower concentrations of BSA, mannitol crystallized in both hemihydrate and anhydrous forms, and trehalose as dihydrate. The extent of dehydration during subsequent drying was dictated by the trehalose to BSA ratio in the formulation. A gradual increase in the Johari-Goldstein relaxation time was observed as the concentration of trehalose increased in the formulation. BSA was more susceptible to stresses from thawing than drying.

Osmotic dehydration kinetics of biofortified yellow-flesh cassava in contrast to white-flesh cassava (Manihot esculenta).

In recent times, the cultivation, processing and consumption of biofortified yellow-flesh cassava is of significant interest to breeders and food processors due to its relatively high pro-vitamin-A content, compared to the conventional white-flesh cassava. In light of this, osmotic dehydration (OD) kinetics of a recently released biofortified yellow-flesh cassava was compared to that of a white-flesh cassava, using salt, sugar, and salt-sugar solutions at different temperatures (30, 45, 60°C) and fixed cube/solution-ratio. Water loss (WL) and solids gain (SG) data were fitted by non-linear regression using four models (Page, Weibull, Azuara, and Peleg). Azuara model was most appropriate in describing OD kinetics for both cultivars. Azuara estimates for equilibrium WL and equilibrium SG, respectively, ranged between 0.101-0.120 and 0.049-0.094g/g for salt solution, 0.158-0.212g/g and 0.107-0.268g/g for sugar solution and 0.234-0.306g/g and 0.189-0.276g/g for salt-sugar solution. The best conditions for OD of both cultivars by salt solution and sugar solution was at 60°C and 45°C, respectively, while that for salt-sugar solution varied with cultivar. Increasing temperature increased water loss and solids gain. Salt-OD conformed to Arrhenius temperature dependence of diffusivity, but sugar-OD and salt-sugar-OD did not. Micrographs reveal biofortified yellow-flesh cassava was more susceptible to cell wall collapse than white-flesh cassava. Extent of dehydration by OD agents ranked: salt-sugar > sugar > salt. Osmotic dehydration may be useful as a means of dehydration for cassava prior to drying, and is especially relevant for the carotenoids-rich biofortified yellow cassava.

Evidence for Redox Mechanisms in Organometallic Chemisorption and Reactivity on Sulfated Metal Oxides.

The chemical and electronic interactions of organometallic species with metal oxide support materials are of fundamental importance for the development of new classes of catalytic materials. Chemisorption of Cp*(PMe3)IrMe2 on sulfated alumina (SA) and sulfated zirconia (SZ) led to an unexpected redox mechanism for deuteration of the ancillary Cp* ligand. Evidence for this oxidative mechanism was provided by studying the analogous homogeneous reactivity of the organometallic precursors toward trityl cation ([Ph3C]+), a Lewis acid known to effect formal hydride abstraction by one-electron oxidation followed by hydrogen abstraction. Organometallic deuterium incorporation was found to be correlated with surface sulfate concentration as well as the extent of dehydration under thermal activation conditions of SA and SZ supports. Surface sulfate concentration dependence, in conjunction with a computational study of surface electron affinity, indicates an electron-deficient pyrosulfate species as the redox-active moiety. These results provide further evidence for the ability of sulfated metal oxides to participate in redox chemistry not only toward organometallic complexes but also in the larger context of their application as catalysts for the transformation of light alkanes.

Grand Canonical Monte Carlo coupled multiscale simulation for electrochemical and solvent parameters of silver halide systems in water

Grand Canonical Monte Carlo methods in conjunction with continuum Multiscale simulation to estimate the hydration energies and surface potentials of silver halides as demonstrated elsewhere is employed by incorporating random distribution of molecules, nearest neighbor distances and hydration numbers. The extent of dehydration during each step and the corresponding variation in the hydration numbers are evaluated, assuming the validity of hard spheres. These estimates are then employed to deduce the redox potential of the reaction viz. 2AgX(solution)⇔2Ag(solid)+X2(gas). The dependence of these values on the nature of the halides and solvation characteristics is indicated.

Numerical simulations of CO2 migration during charnockite genesis

Charnockite is considered to be generated either through the dehydration of granitic magma by CO2 purging or by solid-state dehydration through CO2 metasomatism during granulite facies metamorphism. To understand the extent of dehydration, CO2 migration is quantitatively modeled in silicate melt and metasomatic fluid as a function of temperature, H2O wt%, pressure, basal CO2 flux and dynamic viscosity. Numerical simulations show that CO2 advection through porous and permeable high-grade metamorphic rocks can generate dehydrated patches close to the CO2 flow path, as illustrated by the occurrences of ``incipient charnockites.'' CO2 reaction-front velocity constrained by field observations is 0.69 km/m.y., a reasonable value, which matches well with other studies. On the other hand, temperature, rate of cooling, and basal CO2 flux are the critical parameters affecting CO2 diffusion through a silicate melt. CO2 diffusion through silicate melt can only occur at temperature greater than 840 degrees C and during slow cooling (<= 3.7 x 10(-5) degrees C/yr), features that are typical of magma emplacement in the lower crust. Stalling of CO2 fluxing at similar to 840 degrees C explains why some deep-level plutons contain both hydrous and anhydrous (charnockitic) mineral assemblages. CO2 diffusion through silicate melt is virtually insensitive to pressure. Addition of CO2 basal flux facilitates episodic dehydrated melt migration by generating fracture pathways.

Crystal structure and dehydration behavior of E6070, a novel IKKβ protein kinase inhibitor for the treatment of rheumatoid arthritis

This study is focused on solving the crystal structure of E6070, a novel IKKβ protein kinase inhibitor, and characterizing its solid state. E6070 exists as a stable crystalline trihydrate (hydrate I) that undergoes two dehydration events on heating. Neither crystal form nor water content changed under the relative humidity range from 11% to 93% at 25°C. Crystal transformation to hydrate II occurred in the first dehydration process beginning at ∼70°C followed by loss of almost all remaining crystal lattice water as heating continues up to 160°C. The observed weight loss of the first step was significantly higher than two equivalents of water. The X-ray powder diffraction proved that the anhydrate is an amorphous form that reversibly reforms the original trihydrate when exposed to atmospheric moisture. Hydrate II more readily forms hydrate I than from the anhydrate. The activation energy of the second step accompanied with amorphism was approximately 1.5 times greater than that of the first. In addition, a gradual decline of activation energy depending on the extent of dehydration was observed, implying reversible conversion in both steps. Therefore, the trihydrate was considered suitable for further development as its solid state is controllable during the manufacturing processes and the shelf life.

Degradation of Parachlorophenol by Electro-Fenton and Photo-Fenton Process Using Batch Recirculation Reactor

Chlorophenols are a group of special interest due to their high toxicity and low bio degradability. Advanced oxidation process constitutes a promising technology for the treatment of wastewaters containing non-easily removable organic compounds. Several electro chemical processes are based on mediated electro chemical oxidation. The present study envisages the utility of electro-fenton and photo-fenton process for the degradation of parachlorophenol from aqueous solution by the electro oxidation under acidic condition. Experiments were carried out under batch recirculation conditions with stainless steel as cathodes and RuO2 coated titanium expanded mesh as anodes. Electrolysis was carried out with various current densities and flow rate using mediated electro chemical oxidation process with fenton mediator (Fe2+ / Fe3+ + H2O2). Extent of dehydration and reduction in COD was studied as a function of applied current, electrolysis time and concentration of ferrous ion. The electrolysis was carried at optimised conditions to achieve efficiencies higher than 80%.

Adequately assessing dehydration: A holy grail of paediatric emergency medicine

In a commentary on recent papers which have aimed to improve the recognition of dehydration in children the challenges of assessing and managing this very common condition are discussed. It can be argued if those assessing and validating the extent of dehydration in studies are specifically trained to do so they do not represent a pragmatic representative version of the actual clinical assessment that may occur by untrained staff.

Physiological consequences of desiccation in the aquatic bryophyte Fontinalis antipyretica

The moss Fontinalis antipyretica, an aquatic bryophyte previously described as desiccation-intolerant, is known to survive intermittent desiccation events in Mediterranean rivers. To better understand the mechanisms of desiccation tolerance in this species and to reconcile the apparently conflicting evidence between desiccation tolerance classifications and field observations, gross photosynthesis and chlorophyll a fluorescence were measured in field-desiccated bryophyte tips and in bryophyte tips subjected in the laboratory to slow, fast, and very fast drying followed by either a short (30 min) or prolonged (5 days) recovery. Our results show, for the first time, that the metabolic response of F. antipyretica to desiccation, both under field and laboratory conditions, is consistent with a desiccation-tolerance pattern; however, drying must proceed slowly for the bryophyte to regain its pre-desiccation state following rehydration. In addition, the extent of dehydration was found to influence metabolism whereas the drying rate determined the degree of recovery. Photosystem II (PSII) regulation and structural maintenance may be part of the induced desiccation tolerance mechanism allowing this moss to recover from slow drying. The decrease in the photochemical quenching coefficient (qP) immediately following rehydration may serve to alleviate the effects of excess energy on photosystem I (PSI), while low-level non-photochemical quenching (NPQ) would allow an energy shift enabling recovery subsequent to extended periods of desiccation. The findings were confirmed in field-desiccated samples, whose behavior was similar to that of samples slowly dried in the laboratory.

EFFECT OF STORAGE CONDITIONS ON QUALITY ATTRIBUTES OF FRESH-CUT MANGOSTEEN

Fresh-cut mangosteen (Garcinia mangostana L.) is highly susceptible to quality losses due to damaged cells and tissues and lack of protective skin. The appropriate use of storage condition has extensively been reported to be an effective approach to maintain quality of fresh-cut fruits. The objective of this study was to investigate changes in some quality attributes of fresh-cut mangosteens as affected by storage conditions. Mangosteens were peeled and dipped in a solution consisting of 2% sodium erythorbate + 0.2% calcium chloride for 30 min, and then drained prior to storage under three different conditions, including modified atmosphere packaging (MAP; 5% O 2 + 9% CO 2 ), vacuum packaging (VAC) and air (AIR). In all treatments, moisture content, total soluble solids, pH, titratable acidity, color, firmness and sensory acceptance of fresh-cut mangosteens were monitored at 2-day intervals during 14 days of storage at 4°C. During storage, total soluble solids of fresh-cut fruits stored in AIR sharply increased and were considerably higher than those stored in MAP and VAC. Losses of moisture content and firmness were retarded by storage in MAP and VAC, whereas a rapid decline of both quality attributes was found in fruits stored in AIR. Titratable acidity of MAP and VAC-treated fruits gradually decreased, compared with the slight change in AIR-treated fruits as a result of a greater extent of dehydration. However, pH of fruits in all treatments remained somewhat stable during storage. Lightness (L*) decreased to a larger extent in VAC and AIR-stored fruits, whereas a small decrease in MAP-treated fruits were detected. Fresh-cut fruits with MAP treatment obtained the highest sensory scores, compared with other treatments, throughout the entire period of storage. MAP resulted in the best overall retention of quality attributes of fresh-cut mangosteens during postharvest storage.

Structural changes of water in a hydrogel during dehydration

Raman spectra of poly-N,N,-dimethylacrylamide hydrogel were measured in order to investigate the mechanism of the structural changes in water and the polymer network during dehydration. The results show that the vibrational energies of the C=O and the O-H stretching modes increase with the extent of dehydration, whereas that of the CH(3) rocking mode decreases. The energy shifts observed in the C=O stretching and CH(3) rocking modes indicate that the polymer network shrinks with the dehydration and undergoes a glass transition at some point. The energy shifts of the O-H stretching modes are attributed to changes in the water structure with the structural change of the polymer network. By applying a structural model of bulk water to the spectra of the O-H stretching region, the local water structures in the gel and the dried glassy polymer were analyzed. The result shows that a tetragonal water structure consisting of four hydrogen bonds increases in the residual water of the dried glassy polymer, suggesting that the residual water forms a two-dimensional hydrogen-bonded network. The local water structure in a polymer might have important implications for the interpretation of properties of localized water, for instance, water in a mineral crack.

Correlation Between Conduction Behavior of CsH5 ( PO4 ) 2 and Thermal History

The influence of thermal cycle on the conduction behavior of was investigated. The temperature dependence of the conductivity was examined in two consecutive heating processes with different sequential operations under a dry atmosphere. In the second heating, the conduction behavior was significantly affected by the thermal history. This phenomenon could be explained consistently by the results from X-ray diffraction (XRD) and thermal analyses of . When the sample was heated at the melting point of and then rapidly cooled, the diffraction lines of and the condensed phosphates were observed in the XRD pattern. The differential scanning calorimetry and thermogravimetry-differential thermal analysis were conducted in the heating-cooling process under various experimental conditions. It was noted that the crystallization temperature of was strongly dependent on the extent of dehydration.