Hydration Water Research Articles

Proton Conduction in Gly-X (X = Ser, Ser-Gly-Ser) and GS50.

In recent years, the use of biomaterials has been required from the viewpoint of biocompatibility of electronic devices. In this study, the proton conductivity of Glycyl-L-serine (Gly-Ser) was investigated to clarify the relationship between hydration and proton conduction in peptides. From the crystal and conductivity data, it was inferred that the proton conductivity in hydrated Gly-Ser crystals is caused by the cleavage and rearrangement of hydrogen bonds between hydration shells formed by hydrogen bonds between amino acids and water molecules. Moreover, a staircase-like change in proton conduction with hydration was observed at n = 0.3 and 0.5. These results indicate that proton transport in Gly-Ser is realized by hydration water. In addition, we also found that hydration of GSGS and GS50 can achieve proton conduction of Gly-Ser tetrameric GSGS and GS50 containing repeating sequences. The proton conductivity at n = 0.3 is due to percolation by the formation of proton-conducting pathways. In addition to these results, we found that proton conductivity at GS50 is realized by the diffusion constant of 3.21 × 10-8 cm2/s at GS50.

Modulation of ion transport through nanopores in water desalination: a molecular dynamics study

ABSTRACT A good understanding of ion transport mechanisms through nanopores is an important issue for the development of advanced water desalination technologies. We use the molecular dynamics simulation method to systematically investigate the translation dynamics of ions through nanopores in the water desalination process by designing four kinds of nano-membranes based on carbon nanomaterials. Results indicate that circular-shaped pore exhibits better water permeability, nevertheless, the slit pore has a lower resistance due to the larger pore area; nanochannel membranes increase the residence time of ions. Fluorination induces more ordered ionic hydration structures, and enhances Na + -Cl- ion pair association. -OH groups replace partial ionic hydration water molecules and facilitate ions transport into membranes. The -NH3 +, -COO- groups can strongly adsorb the oppositely charged ions, and substantially slow down ion dynamics. Functionalisation within nanochannel interior can further enhance interfacial friction and transport resistance, even causing pore blocking by charged groups. The fluorinated nanochannel membrane demonstrates complete rejection of ions with a water permeability coefficient of 1.88 × 104 L·m−2·h−1·bar−1, breaking the permeability-selectivity trade-off. This study indicates that ion transport in nanopores could be finely modulated to obtain enhanced performance in water desalination.

Hydration and evaporative water loss of lizards change in response to temperature and humidity acclimation.

Testing acclimation plasticity informs our understanding of organismal physiology and applies to conservation management amidst our rapidly changing climate. While there is a wealth of research on the plasticity of thermal and hydric physiology in response to temperature acclimation, there is a comparative gap for research on acclimation to different hydric regimes, as well as the interaction between water and temperature. We sought to fill this gap by acclimating Western Fence Lizards (Sceloporus occidentalis) to experimental climate conditions (crossed design of Hot or Cool, Dry or Humid) for eight days, and measuring cutaneous evaporative water loss (CEWL), plasma osmolality, hematocrit, and body mass before and after acclimation. CEWL changed plastically in response to the different climates, with lizards acclimated to Hot Humid conditions experiencing the greatest increase in CEWL. Change in CEWL among individuals was negatively related to treatment vapor pressure deficit and positively related to treatment water vapor pressure. Plasma osmolality, hematocrit, and body mass all showed greater changes in response to temperature than to humidity or vapor pressure deficit. CEWL and plasma osmolality were positively related across treatment groups before acclimation and within treatment groups after acclimation, but the two variables showed different responses to acclimation, suggesting that they are interrelated but governed by different mechanisms. This study is among few that assess more than one metric of hydric physiology and that test the interactive effects of temperature and humidity. Such measurements will be essential for predictive models of activity and survival for animals under climate change.

Water molecule ordering on the surface of an intrinsically disordered protein

The dynamics and local structure of the hydration water on surfaces of folded proteins have been extensively investigated. However, our knowledge of the hydration of intrinsically disordered proteins (IDPs) is more limited. Here, we compare the local structure of water molecules hydrating a globular protein, lysozyme, and the intrinsically disordered N-terminal of c-Src kinase (SH4UD) using molecular dynamics simulation. The radial distributions from the protein surface of the first and the second hydration shells are similar for the folded protein and the IDP. However, water molecules in the first hydration shell of both the folded protein and the IDP are perturbed from the bulk. This perturbation involves a loss of tetrahedrality, which is, however, significantly more marked for the folded protein than the IDP. This difference arises from an increase in the first hydration shell of the IDP of the fraction of hydration water molecules interacting with oxygen. The water ordering is independent of the compactness of the IDP. In contrast, the lifetimes of water molecules in the first hydration shell increase with IDP compactness, indicating a significant impact of IDP configuration on water surface pocket kinetics, which here is linked to differential pocket volumes and polarities.

Unprecedented, catalyst‐free, and rapid one‐pot, three‐component green synthesis of substituted 3‐hydroxy‐2‐oxindoles in water

AbstractAn efficient, unprecedented, catalyst‐free, and rapid synthesis of substituted 3‐hydroxy‐2‐oxindoles is described by the one‐pot, three‐component reaction of hydrazine hydrate, ethyl acetoacetate, and isatins in water. The reported protocol is a green and general route for the simple preparation of new heteroaromatic substituted 3‐hydroxy‐2‐oxindoles in quantitative yields under very mild reaction conditions by using simple, cheap, and readily available materials. The developed method is effectively applicable to a variety of isatin substrates. Operational simplicity, mild and greener reaction conditions, short reaction time, a wide scope of substrates, good isolated yields of the products, and environmentally benign reaction medium are the distinctive features of the present method.

Experimental study on water transfer mechanism of quicklime modified centrifugal dewatering clay

This study investigates the water transfer mechanism of quicklime modified centrifugal dewatering clay. A small-scale centrifuge device was used to investigate the change of bound water content in modified clay under different laboratory test conditions including quicklime content and curing age, and analyze the water transfer mechanism in the process of quicklime treatment, and its impact on clay properties. The results show that the content of pore water decreased by 6.2% ∼ 16.9%, the content of bound water increased by 4.2% ∼ 12.9%, and the content of hydration water increased by 6.1% ∼ 14.1% due to hydration reaction caused by the quicklime. The increase of quicklime content facilitates the conversion of free water into bound water and hydration water in a relatively short time. The pozzolanic reaction occurs on the surface of the clay particles to absorb free water and convert it into bound water, while part of Ca (OH)2 crystals generated by hydration reaction adhere to the surface of clay particles, grow into needle-shape and fibrous structures, and absorb free pore water and convert it into hydration water. For field applications, the mixing percentage of quicklime is recommended to be below 9% by dry weight. From the cost perspective, 7-day curing age is recommended in the field. The essence of quicklime modification is to transform the free water with relatively low pF potential energy into the bound water and hydration water with relatively high pF potential energy. A schematic diagram of water transfer mechanism was also proposed in this study for quicklime modified clay and validated using the aforementioned experimental data.

Adhesives for medical application - Peel strength testing and evaluation of biophysical skin response

BackgroundMedical adhesives are commonly used for securing wound dressings and medical devices used for diagnostic or therapeutic purposes. Mechanical irritation of skin due to adhesive stripping and repeated application can lead to discomfort and device removal. This study aims to examine the peel strength and skin response to different medical adhesives in a cohort of healthy volunteers. MethodTwelve healthy participants were recruited for peel strength testing of three candidate adhesive tapes, and evaluation of the skin response after adhesive removal. A modified ASTM D903 peel strength testing was performed at 180° peeling angle and a rate of 300 mm/min on the forehead, upper back and forearm skin. A longitudinal study was conducted on the forearm and back, with the adhesive samples left in-situ for up to 60 h for analysis of repeat application. The effects of two skin preparation approaches (water and alcohol cleaning) prior to adhesive application were also assessed. Skin biophysical properties were assessed at baseline and at various timepoints following adhesive removal using transepidermal water loss (TEWL), erythema and hydration. ResultsPeel strength reduced uniformly with repeat application over prolonged periods for all the adhesive samples tested. Skin preparation with water and alcohol cleansing prior to adhesive application increased peel strength at both the back (1.1% and 2.9%), and forearm (21.3% and 20%) sites. There was statistically significant increase from baseline to post-tape application for TEWL, skin redness and hydration (p < 0.001). However, there were no statistically significant differences between adhesive types (TEWL: p = 0.38, SR: p = 0.53, HY: p = 0.46). TEWL increased the most post-adhesion across all test sites and adhesive samples with repeat application (p < 0.05). Two-way ANOVA tests revealed no statistically significant interactions between the effects of application duration and adhesive on skin redness or TEWL for both the back and forearm sites (p > 0.05), though a significant interaction was indicted for hydration at the back site (p = 0.01). ConclusionThis study revealed that site and duration of adhesive application effected peel strength. The corresponding changes in skin properties identified that skin barrier function was disrupted with long-term application of adhesives. The back site was identified to be most reliable for adhesion testing and skin response assessment for future work.

Effects of 1,3-propanediol associated, or not, with butylene glycol and/or glycerol on skin hydration and skin barrier function.

This study aimed to assess the effect of 1,3-propanediol at different concentrations (5%, 10%, or 15%), either applied alone or in combination with butylene glycol (BG) (5%) and/or glycerol (5%), on skin hydration and skin barrier function. The measurements were conducted using capacitance to determine skin hydration and trans epidermal water loss (TEWL) rates to evaluate skin barrier function. A total of 30 healthy female subjects participated in the study. Capacitance and TEWL measurements were conducted at multiple time points, including before application and at 15 min, 2 and 8 h after the humectants were applied to the forearms of the subjects. All the subjects provided written informed consent. The 1,3-propanediol in all concentrations and in all combinations (with BG and/or glycerol) increased skin hydration and improved skin barrier function 15 min, 2 and 8 h after application. Glycerol increased the hydration performance of 1,3-propanediol. The application of 1,3-propanediol at a concentration of 15%, either alone or in combination with other humectants, reduced the TEWL to a greater extent than lower concentrations of 1,3-propanediol. Furthermore, the addition of glycerol to 1,3-propanediol 15% improved the skin barrier and reduced TEWL when compared with 1,3-propanediol alone and with the combination of 1,3-propanediol + BG. The humectants significantly improved skin hydration and reduced TEWL throughout the 8-h time course. The increase in 1,3-propanediol concentration, as well as its combination with glycerol, provided a greater benefit to the skin, improving both hydration and the skin barrier function.

Direct Air Capture: Effects of Low-Purity CO2 and Geological Depths on Post-Capture Compression Energy and Storage

Phreeqc software has been successfully employed to study the behaviour of the gypsum rock-water system under different conditions and various levels of impurities present in the injected CO2 stream. The dissolution of gypsum leads to the increase in water quantity because of release of hydration water molecules. Under the conditions at 1km geological depth, an anhydrite (CaSO4) produced remained dissolved in the solution while the pH slightly drops owing to sulphate ions generation. As the pressure and temperature increase at 1.5km depth, more gypsum dissolves until at 2.5km depth where excess rise in temperature inhibits gypsum dissolution. The injection of pure CO2 leads to the production of calcite in the solution, which continues to grow as more CO2 is injected. But, the presence of impurity such as N2 in the CO2 stream inhibits formation of calcite, owing to continuous dissolution/ionization of calcium. Other carbonate crystals were similarly affected while the pH continues to drop drastically. It is inferred that the presence of impurities such as N2 in the CO2 stream complicates carbonation mechanisms and inhibits formations of the carbonate crystals.

Characterization of texturized meat analogues containing native lupin flour and lupin protein concentrate/isolate

Lupin is a nutritious, yet undervalued grain used as a fodder and food crop. In the present study, native lupin flour (LF), lupin protein concentrate (LPC), and lupin protein isolate (LPI) were combined (70% LPI:LPC blend ratios [30:70, 50:50, and 70:30] and 30% LF constant fraction), extruded at high moisture (45–55%), and shaped with a long cooling die (800 mm) to obtain texturized meat analogues (TMAs) with fibrous structures. The characteristics of TMAs (e.g., hardness, water hydration capacity) depended heavily on water content, blend ratios (LPI:LPC), and to a lesser extent, the long cooling die temperature. Color changes (i.e., L*, b*) were mostly attributed to variations in blend ratios (LPI:LPC). Microstructure analysis showed that TMAs with higher water content (55%) were more likely to have thinner walls and smaller void thickness. Fluorescence imagery revealed that TMAs with lower LPI content presented more homogeneous structures. These findings show that reasonable amounts (30% d.m.) of native lupin flour can be incorporated into meat analogues by maintaining a sufficiently high protein content (>50% d.m.) to trigger the formation of fibrous structures.

Competition between Solvent···Solvent and Solvent···Solute Interactions in the Microhydration of the Tetrafluoroborate Anion, BF4-(H2O)n=1,2,3,4.

This study systematically examines the interactions of the tetrafluoroborate anion (BF4-) with up to four water molecules (BF4-(H2O)n=1,2,3,4). Full geometry optimizations and subsequent harmonic vibrational frequency computations are performed using a variety of density functional theory (DFT) methods (B3LYP, B3LYP-D3BJ, and M06-2X) and the MP2 ab initio method with a triple-ζ correlation consistent basis set augmented with diffuse functions on all non-hydrogen atoms (cc-pVTZ for H and aug-cc-pVTZ for B, O, and F; denoted as haTZ). Optimized structures and harmonic vibrational frequencies were also obtained with the CCSD(T) ab initio method and the haTZ basis set for the mono- and dihydrate (n = 1, 2) structures. The 2-body:Many-body (2b:Mb) technique, in which CCSD(T) computations capture the 1- and 2-body contributions to the interactions and MP2 computations recover all higher-order contributions, was used to extend these demanding computations to the tri- and tetrahydrate (n = 3, 4) systems. Four, five, and eight new stationary points have been identified for the di-, tri-, and tetrahydrate systems, respectively. The global minimum of the monohydrate adopts a symmetric double ionic hydrogen bond motif with C2v symmetry and an electronic dissociation energy of 13.17 kcal mol-1 at the CCSD(T)/haTZ level of theory. This strong solvent···solute interaction, however, competes with solute···solute interactions in the lowest-energy BF4-(H2O)n=2,3,4 minima that are not seen in the other di-, tri-, or tetrahydrate minima. The latter interactions help increase the 2b:Mb dissociation energies to more than 26, 41, and 51 kcal mol-1 for n = 2, 3, and 4, respectively. Structures that form hydrogen bonds between the solvating water molecules also exhibit the largest shifts in the harmonic OH stretching frequencies for the waters of hydration. These shifts can exceed -280 cm-1 relative to an isolated H2O molecule at the 2b:Mb/haTZ level of theory.

Comparison of hydration water properties of common and durum wheat brans upon grinding with different loading modes

Wheat bran brings healthy properties in food products. However, its incorporation requires a first milling step during which it is subject to various loading modes which have an influence on its properties. This study investigated the influence of the loading modes (high shear or impact) generated by grinders during the milling on the hydration properties of common and durum wheat brans. An original study at molecular scale to target the distribution and intensity of hydration water bonds was carried out by gravimetric and spectroscopic methods. Results were analyzed in regards to the particle size distribution and shape factors as well as biochemical composition to highlight the process-structure-function relationships at macro and microscales. Impact grinder has a stronger effect on water vapor sorption capacity and FTIR multimer water at 3600 cm−1 of durum wheat bran as well as a red shift in the band at 1030 cm−1 related to a high decrease in residual starch crystallinity degree (about 17%). High shear grinder tends to increase the proportion of water strongly bound. Low field NMR analysis revealed differences in the high mobility water peak and a significant lower relaxation time T2 for native and ground durum wheat bran (up to 1.7 fold less).

Investigating the Water Relations in Aqueous Extract Powders of Mango (Mangifera indica) Peel and Seed Waste for Their Use in Food Matrices as a Value-Added By-Product.

This study investigated the potential uses of discarded mango peel and seed parts by analyzing their water sorption behavior, hydration kinetics, and stability when converted into extract powders at pH 3 and 10. The results revealed that peel extracts had a higher water adsorption capacity compared with seed extracts due to differences in their composition. Peel extracts were primarily composed of carbohydrates (approximately 75%) with a low protein content, while seed extracts contained fewer carbohydrates (less than 30%) but higher levels of proteins (more than 30%) and lipids. The critical water content for maintaining the glassy state of peel extract powders during storage was found to be 0.025 and 0.032 g of water/g for extracts obtained at pH 3 and 10, respectively. In contrast, the Tg values of seed extracts remained relatively unchanged across different water content levels, suggesting that proteins and lipids inhibited the water's plasticizing effect in the solid matrix. These findings indicate that both mango waste fractions exhibit distinct hygroscopic behaviors, necessitating different approaches to processing and utilization. These extracts hold potential applications for various food products such as beverages, gels, sauces, or emulsions, contributing to the reduction in waste and the creation of value-added products from mango residues.

Effect of the Hypoxic Chamber Training Series on Skin Characteristics of Overweight and Obese Women

Obesity is a disease of civilization. The COVID-19 pandemic has caused an increase in its incidence; therefore, there is an increasing emphasis on programs aimed at improving body composition, often through physical activity. Various modifications to training interventions are being introduced, including the modification of the thermo-climatic conditions of the training. However, to date, whether such a modification is safe for the skin has not been studied. The purpose of this study was to evaluate the effects of a series of workouts in a hypoxic chamber on skin characteristics such as elasticity, hydration, and transepidermal water loss (TEWL). Women who were overweight or obese were invited to participate in the project. The workouts took place in a hypoxic chamber where conditions were mimicked at 2500 m, three times a week for a period of four weeks, for 60 min each. Finally, the results from 11 women in the study group and 9 in the control group were included in the analysis. Body composition analysis was performed, and venous blood was drawn (morphology and lipidogram). No statistically significant changes in skin firmness or the amount of TEWL were observed in the subjects. An increase in skin hydration on the hand was observed only after the first workout (p = 0.046), while skin hydration on the mandible did not change. A significant reduction in body weight (p = 0.042), BMI (p = 0.045), and TBW (p = 0.017) was indicated in the study group. The control group showed an increase in BMI (p = 0.045) and VFA (p = 0.042). There was no correlation between measured skin characteristics and body composition indices or the results of blood indices. A correlation was observed between TEWL and lipidogram results. Training under hypoxic conditions does not affect skin features in overweight and obese women. Even a significant reduction in TBW did not result in a decrease in hydration. It was also shown that the proper barrier function of the skin is closely dependent on the serum lipid profile.

Chromium removal from chromium gypsum through microwave hydrothermal crystal phase regulation.

Chromium gypsum (CG) is a common hazardous waste formed in chromium salt or electroplating industries. The trapped or lattice-doped CrO42- in gypsum crystals are difficult to be reduced or removed by traditional methods, which will be re-oxidized or slowly released during long-term hypaethral storage. In this study, microwave hydrothermal treatment was applied to remove chromium in CG. Under optimal conditions (solid-liquid ratio of 1:5, 0.1M sulfuric acid as liquid media, and 110°C), over 99% of the chromium in CG can be removed within 10min. XRD spectra indicated that 59.8% gypsum was transformed to from dihydrate gypsum to hemihydrate gypsum. The toxicity leaching test shows that chromium in CG is 377.0mg/L before detoxification and 0.55mg/L after detoxification, which proves that chromium in CG lattice can be efficiently removed. This work enables to significantly advance the dehydration phase transformation process of gypsum and release the heavy metal impurities within it more quickly and provides new possibilities to treat similar solid waste containing gypsum or minerals with hydration water.

Effect of solvent viscosity on the activation barrier of hydrogen tunneling in the lipoxygenase reaction

Hydrogen tunneling in enzyme reactions has played an important role in linking protein thermal motions to the chemical steps of catalysis. Lipoxygenases (LOXs) have served as model systems for such reactions, showcasing deep hydrogen tunneling mechanisms associated with enzymatic C–H bond cleavage from polyunsaturated fatty acids. Here, we examined the effect of solvent viscosity on the protein thermal motions associated with LOX catalysis using trehalose and glucose as viscogens. Kinetic analysis of the reaction of the paradigm plant orthologue, soybean lipoxygenase (SLO), with linoleic acid revealed no effect on the first-order rate constants, kcat, or activation energy, Ea. Further studies of SLO active site mutants displaying varying Eas, which have been used to probe catalytically relevant motions, likewise provided no evidence for viscogen-dependent motions. Kinetic analyses were extended to a representative fungal LOX from M. oryzae, MoLOX, and a human LOX, 15-LOX-2. While MoLOX behaved similarly to SLO, we show that viscogens inhibit 15-LOX-2 activity. The latter implicates viscogen sensitive, conformational motions in animal LOX reactions. The data provide insight into the role of water hydration layers in facilitating hydrogen (quantum) tunneling in LOX.

Bi-salts composites to enhance the hydration kinetics and heat storage capacity

In this study, salt hydrates were deposited on a porous carbon (PC) support to address the challenges associated with maintaining heat capacity and slow hydration kinetics in thermochemical heat storage (THS) systems. Mono-salt (MgSO4) or binary salt (MgSO4-MgCl2) composites on the PC were analyzed by thermogravimetry/differential scanning calorimetry (TG/DSC). The results show that binary salt composites exhibit faster hydration kinetics and higher water adsorption capacity than monosalt composites. The addition of MgCl2 overcomes the kinetic drawbacks caused by the hydrophobic nature of the support and the presence of salt aggregates. The PC_60binary composite achieves a water uptake of 0.75 g/g, exceeding the water uptake of PC_60MgSO4 (0.48 g/g). Furthermore, the heat released by the composites follows a similar trend to water sorption. PC_60MgSO4 produces 52 % (1356 J/g) of the heat released by pure MgSO4, while PC_60binary achieves 70 % (1840 J/g) of the heat released by pure mixed salts. These results suggest that the newly developed binary salt composites are promising for long-term heat storage applications. These experimental results highlight the improved performance of binary salt composites in terms of hydration kinetics, water adsorption and heat release. This study provides valuable pointers for the development of more efficient THS systems.

Nucleation of carbon dioxide hydrate in water with variable salt composition

It has been shown that in the carbon dioxide–water system, the rate of gas hydrate nucleation increases with decreasing pH of the aqueous phase. Thus, a new approach has been demonstrated to control the rate of nucleation of carbon dioxide hydrate. Of interest is the question of the prospects for extending this approach to control the nucleation of other hydrates.

Study on the mechanical properties of Self-Curing Concrete Using Magnetized Water

The growth of the population has led to an increase in construction activities, which require water for concrete mixing, curing, and cement hydration. Cement hydration occurs due to extra water that is not part of the mixing water. Magnetized water, which is water subjected to magnetic flux, has become a popular technology in the construction industry due to its potential to increase the lifespan of buildings and improve various technological processes at an economical cost. The use of magnetically processed water reduces the amount of cement needed to achieve the desired compressive strength value. This study investigates the effects of magnetic field generated by Permag N-406 on the properties of water, such as pH and hardness also, cement is partially replaced with 1%-4% of Nano Silica to achieve good characteristic strength. The study determines the optimal magnetization value, the maximum exposure time of water to the magnetic field and, the mechanical properties of self-curing concrete. Polyethylene Glycol (PEG) is used as the self-curing agent. The experiment results shows that the 48 hrs of magnetization of water and replacement of cement by 3% of Nano Silica showed the better performances in mechanical properties.

Base pair compositional variability influences DNA structural stability and tunes hydration thermodynamics and dynamics.

DNA deformability and differential hydration are crucial determinants of biological processes ranging from genetic material packaging to gene expression; their associative details, however, remain inadequately understood. Herein, we report investigations of the dynamic and thermodynamic responses of the local hydration of a variety of base pair sequences. Leveraging in silico sampling and our in-house analyses, we first report the local conformational propensity of sequences that are either predisposed toward the canonical A- or B-conformations or are restrained to potential transitory pathways. It is observed that the transition from the unrestrained A-form to the B-form leads to lengthwise structural deformation. The insertion of intermittent -(CG)- base pairs in otherwise homogeneous -(AT)- sequences bears dynamical consequences for the vicinal hydration layer. Calculation of the excess (pair) entropy suggests substantially higher values of hydration water surrounding A conformations over the B- conformations. Applying the Rosenfeld approximation, we project that the diffusivity of water molecules proximal to canonical B conformation is least for the minor groove of the canonical B-conformation. We determine that structure, composition, and conformation specific groove dimension together influence the local hydration characteristics and, therefore, are expected to be important determinants of biological processes.