Hydration Water Research Articles

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.

Unsaturated water flow-induced the structure variation of gas hydrate reservoir and its effect on fluid migration and gas production

Multi-phase (gas, saturated water, and unsaturated water) seepage is bound to exist in natural gas hydrates (NGHs) production process. The effect of water flow, especially for unsaturated water flow, on the permeability variation of hydrate reservoir and gas production behavior do not appear well understood. In this study, the unsaturated water flow in hydrate-bearing sediment and hydrate-free sediment is simulated by controlling water flow velocity. The hydrate phase distribution was monitored using visualization magnetic resonance imaging system. The variation of temperature, pressure, and gas production rate during the unsaturated water flow were analyzed. The results show that the changing trend of the pressure difference presented the three stages for the hydrate-free sediment. In contrast, the pressure difference followed a five-stage change for the hydrate-bearing sediment in the unsaturated water flow process due to the hydrate dissolution. The hydrate dissolution caused an increase in permeability (maximum of log10(Kr) was 0.5) and formed the obvious unsaturated water flow channel. Moreover, the higher water flow velocity, which increased the chemical potential difference between hydrate phase and water phase, accelerated the MH dissolution, and further induced the faster increase rate of permeability and gas production. Surprisingly, when the unsaturated water flow velocity was improved to 15 mL/min from 0.5 mL/min, the gas production rate increased by 35 times. Furthermore, the average gas production rate was mainly determined by the unsaturated water flow velocity, it was changing in a linear fashion with the increasing water flow velocity. The findings could provide new knowledge on the strategy design on NGHs production with high efficiency.

The Intermediate Water Concept for Pioneering Polymeric Biomaterials: A Review and Update

Abstract Polymeric biomaterials are often used in water and hydration water molecules with different mobilities, such as non-freezing water, intermediate water, and free water, are formed on their surfaces. These water molecules affect biological responses between the biomaterials and biofluids. It is challenging to control the state of hydration waters by tuning chemical structures of the polymers toward advance of medical fields. This review describes and updates syntheses, analyses, and applications of the polymeric biomaterials based on the intermediate water concept. The concept provides significant opportunities for pioneering polymeric biomaterials.

Computational workflow for discovering small molecular binders for shallow binding sites by integrating molecular dynamics simulation, pharmacophore modeling, and machine learning: STAT3 as case study.

STAT3 belongs to a family of seven transcription factors. It plays an important role in activating the transcription of various genes involved in a variety of cellular processes. High levels of STAT3 are detected in several types of cancer. Hence, STAT3 inhibition is considered a promising therapeutic anti-cancer strategy. However, since STAT3 inhibitors bind to the shallow SH2 domain of the protein, it is expected that hydration water molecules play significant role in ligand-binding complicating the discovery of potent binders. To remedy this issue, we herein propose to extract pharmacophores from molecular dynamics (MD) frames of a potent co-crystallized ligand complexed within STAT3 SH2 domain. Subsequently, we employ genetic function algorithm coupled with machine learning (GFA-ML) to explore the optimal combination of MD-derived pharmacophores that can account for the variations in bioactivity among a list of inhibitors. To enhance the dataset, the training and testing lists were augmented nearly a 100-fold by considering multiple conformers of the ligands. A single significant pharmacophore emerged after 188ns of MD simulation to represent STAT3-ligand binding. Screening the National Cancer Institute (NCI) database with this model identified one low micromolar inhibitor most likely binds to the SH2 domain of STAT3 and inhibits this pathway.

Conformational Fluctuations and Induced Orientation of a Protein, Its Solvation Shell, and Bulk Water in Weak Non-Unfolding External Electric Fields.

Extreme external electric fields have been reported to disrupt the tertiary structure of stably folded proteins; however, the effects of weaker electric fields on many biomolecules, especially net-uncharged proteins, and on the surrounding aqueous environment have been rarely discussed. To explore these effects at the atomic level, here, we have used molecular dynamics simulations to estimate rotational motion and induced structural fluctuations in the model protein ubiquitin and its hydration layer due to applied non-unfolding electrostatic fields. When exposed to weak electric fields of up to 0.2 V nm-1, ubiquitin displayed competition between internal structure-maintaining molecular interactions and the external orienting force, which disrupted the local structure in certain regions of the protein. Moreover, relative to hydration water, bulk water showed a greater tendency to align with the electric field, indicating that the presence of protein caused hydration water to acquire rotational mobility different from that in a pure-water system. The differential influence of the applied electric field on the hydration and bulk water surrounding ubiquitin will be common to almost all (nonmembrane) biomacromolecules. Our findings highlight the importance of local dipoles and their electric polarizability even in net-uncharged biomolecules.

Pressure-driven Li+/Mg2+ selective permeation through size-sieving nanochannels: The role of the second hydration shell

Non-equilibrium molecular dynamics simulations were carried out to investigate the size-sieving mechanism of the permselective transport of Li+ and Mg2+ through one-dimensional nanochannels modelled by carbon nanotubes. Ion transmembrane permeation was driven by a pressure gradient of 100 MPa for mimicking the commonly used pressure-driven processes. It was found that the ions experienced a dehydration of the second hydration shell for squeezing into the nanochannels, during which the first hydration shell was well retained. The second hydration shell was clearly found to play an important role in the pressure-driven ion transmembrane permeation. Due to the different affinities of Li+ and Mg2+ to the surrounding hydration water, the Li+ and Mg2+ ions exhibited distinct abilities in the dehydration of the second hydration shells, producing excellent Li+/Mg2+ permselectivity of 2.63. The novel understanding of the mechanism of Li+/Mg2+ transmembrane permeation will efficiently guide the development of high-performance membrane for Li+/Mg2+ separation.

Hydration, mechanical and transfer properties of blended cement pastes and mortars prepared with recycled powder or limestone filler

The fine fraction (<80 μm) of recycled aggregates from construction and demolition wastes, currently considered as waste, is investigated as a candidate mineral additive for partial replacement of Ordinary Portland Cement (OPC) to reduce the environmental impact of cementitious materials. Although recycled powder could affect hydration reactions due to the presence of residual anhydrous cement particles and to its high specific surface area, very few studies are available in literature concerning these aspects. Cement pastes and mortars prepared with 0%, 10%, and 20% replacement by weight of OPC by either Recycled Powder (RP) or Limestone Filler (LF) are compared in terms of hydration degree, mechanical and transport properties using several techniques, including Isothermal Calorimetry (IC), Thermogravimetric Analysis (TGA), water porosity, mercury intrusion porosimetry and gas permeability. The results revealed that mixtures blended with RP or LF have a similar decrease in the overall hydration degree compared to the hydration degree of pure OPC mixture due to a dilution effect, although both additives have a small reactivity. A moderate increase in porosity and intrinsic permeability with the replacement rate is observed. Pastes and mortars blended with RP have a compressive strength and a Young modulus nearly identical to those with the same amount of LF, despite RP having worse properties than LF. A multiscale micromechanical model is established and reproduces faithfully these experimental results for the elastic moduli, based on the simplified assumptions that LF is nearly inert while RP reduces the effective water to binder ratio by both absorption of water and internal hydration reactions.