Water Mobility Research Articles

Does Pb2+ Form Holodirected or Hemidirected Solvation Geometries in Water?

The hydration properties of the Pb2+ ion in aqueous solution have been investigated by using a synergic approach based on Classical and Car-Parrinello molecular dynamics (CPMD) simulations and extended X-ray absorption fine structure (EXAFS) spectroscopy. A definite answer has been given to the main question on the Pb2+ hydration structure, which concerns the formation of either holodirected or hemidirected solvation geometries, such terms referring to the arrangements of the ligands that can be directed either throughout the surface of an encompassing globe around Pb2+ or throughout only part of the globe, respectively. Our CPMD results show that the Pb2+ ion in water forms a hemidirected 4-fold cluster with a well-defined distorted pyramidal geometry. This cluster is directed throughout one side of the first shell globe, while the other side contains either two or three very mobile water molecules that do not form a well-defined geometry around the Pb2+ ion. The Pb2+ first shell structural arrangement determined from the CPMD simulation was confirmed by the EXAFS experimental results. A homodirected Pb2+ first shell complex like the 8-fold SAP structure obtained from the classical MD simulations cannot be reconciled with the EXAFS experimental data. These findings represent a significant step forward in the understanding of the solvation chemistry of the Pb2+ ion, which is fundamental to improving the efficiency of lead removal procedures that are crucial to the safety of water resources.

Development and validation of a rapid HPLC-MS/MS method for simultaneous determination of cyclosporine A and tacrolimus in whole blood for routine therapeutic drug monitoring in organ transplantation.

Therapeutic drug monitoring is an integral part of organ transplantation. A rapid, simple, economical, and robust high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for simultaneously determining the immunosuppressants cyclosporine A and tacrolimus might increase detection efficiency. In this study, we developed and validated a rapid HPLC-MS/MS method. Whole blood samples of 100 μL were prepared by protein precipitation with acetonitrile and 0.5mol. L-1 ZnSO4. Chromatography was performed on a pre-column using a gradient elution with 20mmol. L-1 ammonium formate and 0.1% (v/v) formic acid in water (mobile phase A) and 0.1% (v/v) formic acid in methanol (mobile phase B) at a flow rate of 1.5mL.min-1. The analysis time was 2.2min. Electrospray ionization and multiple reaction monitoring were performed. The lower limit of quantification was set at 1ng. L-1 for tacrolimus and 50 ng. L-1 for cyclosporine A. The method showed adequate accuracy and precision with a sufficient linear range. The calibration curve range of tacrolimus and cyclosporine A was 1-30 and 50-1500 ng·mL-1, respectively. All correlation coefficients were >0.99. The developed HPLC-MS/MS is rapid and can be used for simultaneous monitoring of tacrolimus and cyclosporine A.

Keeping Clean: A Qualitative Analysis of Water, Sanitation, and Hygiene Among Residents of Recreational Vehicles in Seattle, WA US

The growing number of people living in vehicles in the urban United States in recent years makes their water, sanitation, and hygiene (WASH) an increasingly relevant public health issue. The WASH context of people living in recreational vehicles (RVs) presents unique challenges, especially as it relates to wastewater disposal. This study answers the question: How do RV residents typically manage their wastewater and meet their other WASH needs? We examined the experiences of RV residents in Seattle, Washington participating in Seattle Public Utilities’ mobile pump-out program, which has offered a free, typically monthly, door-to-door RV wastewater disposal service since 2020. We conducted semi-structured interviews with 31 clients and analyzed the data using qualitative content analysis. We found that RV resident water and hygiene experiences were similar to other urban unhoused populations, whereas their sanitation experiences were quite distinct, most notably with regard to open defecation prevalence and the relative risks of shared versus private sanitation. We proposed four WASH service delivery models that consider the possible implications of our findings for cities looking to engage with RV residents. The models included: mobile RV wastewater collection and water delivery, fixed RV dump stations and water resources, public WASH facilities available for all, and safe parking programs.

Mass transfer kinetics of ultrasonic- and vacuum-ultrasonic-assisted static brine of chicken breast (Pectoralis major).

The aim of this study was to investigate the effect of different ultrasound treatment (UT) conditions (Control, UT-150, UT-300, UT-450, Vacuum-UT-150, Vacuum-UT-300, Vacuum-UT-450) on the brining kinetics and meat quality of chicken breast. The results showed that vacuum-ultrasonic-assisted treatment greatly accelerated the transfer of moisture and NaCl, and the highest yield was obtained by ultrasonic power of 450W. The mass transfer kinetics (k1 and k2) were significantly related to vacuum pretreatment and ultrasonic power. The values of k1 for total and moisture weight changes decreased with the increase of ultrasonic power, whereas the values of k2 increased with vacuum pretreatment. The application of ultrasound treatment with vacuum improved the NaCl effective diffusion coefficients (De) from 1.189×10-9 to 1.308-1.449×10-9 m2/s, and the highest De was found with Vacuum-UT-450. The treatment of ultrasound and vacuum can reduce shear force and enhance the water-holding capacity (WHC). According to the analysis of water distribution, vacuum and ultrasound could decrease the T23 values, indicating that the mobility of water decreased. The result of microscopic observation further supported that the disruption of myofibrils was related to the tenderness and WHC changes, which was caused by vacuum and ultrasound treatment. Thus, Vacuum-UT brining could be employed as an emerging technology for improving the efficiency of brining and meat quality of other meat. PRACTICAL APPLICATION: Vacuum-ultrasonic-assisted static brine is an effective and feasible treatment to replace tumbling treatment for maintaining the integrity of the muscle bundles and accelerating the brining rate.

First Specimens of the Cornutan Stylophora Phyllocystis (Echinodermata) in the Ordovician (Volkhov Regional Stage, Dapingian and Darrivilian) of Baltica and Special Aspects of Stylophora Axial Symmetry

Described two new species of cornutan stylophora of the genus Phyllocystis from the Volkhov Regional Stage (Middle Ordovician, Dapingian) of Baltica. This points to the biogeographic connection between Afro-European part of Gondwana and Baltica since the very beginning of the Middle Ordovician. Both species were confined to cold-water, shallow conditions with low water mobility. Analysis of the axial symmetry of the stylophora and the location of the hydropore indicates the absence of torsion in their ontogeny and the location of the ambulacral system to the right of their anteroposterior axis. To explain this structure, two alternative hypotheses have been proposed: 1) inversion inversion in the development of right and left coelomes; 2) inverted state of stylophora compared to other invertebrates, what makes them similar to the chordates in terms of the position of the dorsal and ventral sides.

Nano fish bone prepared by high-energy media milling extends the shelf life of tofu during cold storage: Unlocking the restriction on water mobility

Nano fish bone prepared by high-energy media milling extends the shelf life of tofu during cold storage: Unlocking the restriction on water mobility

Isolation of ice structuring proteins from winter wheat in frigid region (Dongnongdongmai1) and the effect on freeze–thaw stability of dough

In this study, ice structuring proteins (WISPs) extracted from winter wheat in a frigid region were prepared and added to frozen-thawed dough. The WISPs were characterized, revealing that they contained a higher proportion of hydrophilic amino acids and had a molecular weight of approximately 15 kDa. The highest thermal hysteresis activity (THA) observed was 0.62 °C. The secondary structure of WISPs was determined to be as follows: β-sheet: 49.33 %, random coil: 13.87 %, α-helix: 16.35 %, β-turn: 20.45 %. The study investigated the effects of different additions of WISPs on the water mobility, glass transition temperature, microstructure, rheological properties, and texture analysis of frozen-thawed dough. The results demonstrated that the inclusion of WISPs reduced the fluidity of water and water migration in the dough during the frozen-thawed cycle. This protective effect preserved the internal structure and gluten network of the dough, leading to increased viscosity, elasticity, and improved texture properties of the frozen-thawed dough. Furthermore, the addition of WISPs at concentrations ranging from 0 % to 0.7 % resulted in a 1.8 °C increase in the glass transition temperature (Tg). Overall, these findings suggest that WISPs can serve as a beneficial additive for enhancing the freeze–thaw stability of dough.

Biofilm Growth in Porous Media Well Approximated by Fractal Multirate Mass Transfer With Advective‐Diffusive Solute Exchange

AbstractBiofilm growth in porous media changes not only the hydrodynamic properties of the medium (reduction in porosity and permeability, and increase in dispersivity), but also the transport itself (breakthrough curves display increasingly fast first arrivals and long tails). These features are well reproduced by multicontinuum models (Multi‐Rate Mass Transfer, MRMT) which can be used to describe reactive transport in heterogeneous porous media and facilitate the simulation of reactions that are localized within biofilms. Here, we present a conceptual and numerical model of biochemical reactive transport with dynamic biofilm growth based on MRMT formulations. Mass exchange between mobile water and immobile biofilm aggregates is represented by a memory function, which simplifies definition of MRMT parameters. We successfully tested this model on two sets of laboratory data and found that (a) a basic model based on the growth of uniformly sized biofilm aggregates fails to reproduce laboratory tracer tests and rate of biofilm growth, while a fractal growth model, which we obtain by integrating the memory functions of biofilm aggregates with a power law distribution, does; (b) the biofilm memory function evolves as the biofilm grows; and (c) the early time portion of eluted volume tracer breakthrough curves are independent of flow rate, whereas the tail becomes heavier when the flow rate is decreased, which implies that both advection controlled and diffusion controlled mass exchange coexist in biofilms. These findings imply that porous media biofilms are essentially different from those developing in human tissues or open spaces.

Differential root and cell regulation of maize aquaporins by the arbuscular mycorrhizal symbiosis highlights its role in plant water relations.

This study aims to elucidate if the regulation of plant aquaporins by the arbuscular mycorrhizal (AM) symbiosis occurs only in roots or cells colonized by the fungus or at whole root system. Maize plants were cultivated in a split-root system, with half of the root system inoculated with the AM fungus and the other half uninoculated. Plant growth and hydraulic parameters were measured and aquaporin gene expression was determined in each root fraction and in microdissected cells. Under well-watered conditions, the non-colonized root fractions of AM plants grew more than the colonized root fraction. Total osmotic and hydrostatic root hydraulic conductivities (Lo and Lpr) were higher in AM plants than in non-mycorrhizal plants. The expression of most maize aquaporin genes analysed was different in the mycorrhizal root fraction than in the non-mycorrhizal root fraction of AM plants. At the cellular level, differential aquaporin expression in AM-colonized cells and in uncolonized cells was also observed. Results indicate the existence of both, local and systemic regulation of plant aquaporins by the AM symbiosis and suggest that such regulation is related to the availability of water taken up by fungal hyphae in each root fraction and to the plant need of water mobilization.

Tailoring structural and mechanical properties of konjac glucomannan/curdlan composite hydrogels by freeze-thaw treatment

To improve the gelling properties of konjac glucomannan/curdlan (KGM/CUD) composite hydrogels, KGM/CUD composite hydrogels were treated by freeze-thawing. Herein, we focus on the effects of freeze-thaw cycles, freezing temperature, and freezing time on the structural and mechanical properties of KGM/CUD composite hydrogels. SEM and SAXS results showed that ice crystals generated by freezing extruded the molecular chains and increased the cross-linking density between molecular chains, which resulted in a denser gel microstructure. Among them, the freeze-thaw treatment at −20 °C for 12 h can effectively reduce the correlation length (ξ). According to mechanical testing, freeze-thawed gels for 48 h reached 408-, 826-, and 840-fold of the hardness, gumminess and chewiness of unfrozen, respectively. After freeze-thaw treatment, the energy storage modulus (G') of the gel increased to 9872 Pa, the residual mass after heating was up to 27.9 %, the water holding capacity (WHC) was reduced to 80.85 %. In addition, low-field nuclear magnetic resonance results confirmed that the freeze-thaw treatment promoted the formation of ice crystals from water molecules, which realized the transition of the water state, thus reducing the water mobility of the gel. This study provides a facile and efficient strategy for designing hydrogels products with exceptional texture and sensory characteristics.

Computational Analysis of Amine Functionalization in Zwitterionized Polyether Sulfone Dialysis Membranes

Hemodialysis is a critical treatment for patients with end-stage renal disease (ESRD) who lack kidney transplant options. The compatibility of hemodialysis membranes is vital, as incompatibility can trigger inflammation, coagulation, and immune responses, potentially increasing morbidity and mortality among patients with ESRD. This study employed molecular dynamics simulation (MDS) and molecular docking to assess the hemocompatible properties of Polyether Sulfone (PES) membranes modified via two distinct amine functionalization techniques. The molecular docking results demonstrated that side amine functionalization exhibited a lower affinity energy (−7.6) for fibrinogen compared to the middle amine functionalization (−8.2), suggesting enhanced antifouling properties and superior hemocompatibility. Additionally, side amine functionalization formed hydrogen bonds with four amino acids, enhancing its resistance to protein adhesion compared to three amino acids in the middle amine structure. Furthermore, the molecular dynamics simulations revealed differences in water mobility, with the side amine functionalized membranes showing a lower mobility value (9.74 × 10−7) than those treated with the middle amine method (9.85 × 10−7), indicating higher water stability and potentially better patient outcomes. This study’s findings contribute to the design of more efficient and safer hemodialysis treatments by optimizing membrane materials.

Understanding the Wettability of C1N1 (Sub)Nanopores: Implications for Porous Carbonaceous Electrodes

AbstractUnderstanding how water interacts with nanopores of carbonaceous electrodes is crucial for energy storage and conversion applications. A high surface area of carbonaceous materials does not necessarily need to translate to a high electrolyte‐solid interface area. Herein, we study the interaction of water with nanoporous C1N1 materials to explain their very low specific capacitance in aqueous electrolytes despite their high surface area. Water was used to probe chemical environments, provided by pores of different sizes, in 1H MAS NMR experiments. We observe that regardless of their high hydrophilicity, only a negligible portion of water can enter the nanopores of C1N1, in contrast to a reference pure carbon material with a similar pore structure. The common paradigm that water easily enters hydrophilic pores does not apply to C1N1 nanopores below a few nanometers. Calorimetric and sorption experiments demonstrated strong water adsorption on the C1N1 surface, which restricts water mobility across the interface and impedes its penetration into the nanopores.

Evaluation of moisture migration and microstructure of quick-frozen wet rice flour after freeze-thaw cycles and changes in texture, cooking, and sensory properties.

This study investigated the quality changes of quick-frozen wet rice flour before and after freeze-thaw cycles. As the freeze-thaw cycle was prolonged, the water mobility of quick-frozen wet rice flour decreased and the pore size and porosity of the microstructure increased. As a result, the hardness, cooking loss, water absorption, and water precipitation of the rice flour increased, while the sensory score and viscosity decreased. Correlation analysis showed that porosity was positively correlated with the hardness and water absorption of rice flour, and negatively correlated with structural properties such as shearing work and resilience. Water absorption and water precipitation rate were positively related to cooking loss. Thus, moisture migration in rice flour induced microstructural changes to cause alterations in texture, cooking, and sensory properties. Interestingly, quick-frozen wet rice flour still possessed good texture, cooking, and sensory qualities after two freeze-thaw cycles. This study laid the foundation for the development of high-quality quick-frozen wet rice flour.

Isothermal compressibility and water self-diffusion coefficient in supercooled salt aqueous solutions using the Madrid-2019 model

The isothermal compressibility and self-diffusion coefficient of water in Li + , Na + , K + , Mg 2 + and Ca 2 + chloride and sulfate salts aqueous solutions is calculated by means of molecular simulations using the Madrid-2019 force-field, that uses TIP4P/2005 model for water and assigns scaled charges for ions. Our simulations predict that the isothermal compressibilities of these salts retain the anomalous behaviour of water, i.e. compressibility increases as temperature decreases, contrary to the behaviour of normal liquids. A maximum in the isothermal compressibility, analogous to that of pure water, is observed for some of the salt solutions. For the 1 m NaCl solution, simulations are performed at several pressures up to 1000 bar to estimate the location of the second critical point. We estimate that the liquid-liquid critical point is located at 190 K and 1000 bar, i.e. it is shifted to slightly higher temperatures and lower pressures with respect to the most accurate estimation of its location in pure TIP4P/2005 water (172 K and 1861 bar). Regarding the self-diffusion of water, all salts increase water mobility in the very supercooled regime (at temperatures within 200–230 K), with K 2 SO 4 producing the largest increase in water mobility, while MgCl 2 and MgSO 4 are the least effective in enhancing the self-diffusion coefficient of water.

Irrigation Water Salinity Affects Solute Transport and Its Potential Factors Influencing Salt Distribution in Unsaturated Homogenous Red Soil

As a promising alternative water source to alleviate irrigation water scarcity in red soil regions in southern China, low-quality water could enhance regional water resource utilization and promote sustainable agriculture. However, its soluble salt and ions could affect soil solute distribution and transport, potentially hindering crop growth. Undoubtedly, it is necessary to understand the mechanism of solute transport in red soil under low-quality water irrigation with different water salinity levels. Therefore, a one-dimensional vertical water infiltration experiment and a solute breakthrough experiment were conducted to evaluate the solute transport (soluble salt, Na+, and Cl−) in unsaturated and saturated homogenous red soil at different salinity levels [1 (S1), 2 (S2), 3 (S3), 5 (S5), and 10 (S10) g/L] when irrigated with simulated low-quality water using analytical-grade NaCl. Moreover, the potential factors affecting salt distribution in unsaturated red soil were determined. The findings indicate positive linear relationships between accumulations of three solutes and irrigation water salinity. Generally, the depth of maximum solute concentration increased with the increase in irrigation water salinity. Soluble salt, Na+, and Cl− exhibited early breakthrough and trailing in red soil, but higher irrigation water salinity could reduce PV and retardation. A mobile and immobile water model (MIM) showed that convection was dominant in solute transport in red soil under low-quality water irrigation. D decreased as a power function with increasing irrigation water salinity, while v and R decreased linearly. Furthermore, the red soil can adsorb Cl− resulting from its special charge characteristics under low-quality water irrigation, which may be the main source of salt adsorption. Additionally, v > soil pH > βsalt primarily influenced salt distribution in the 0–40 cm soil profile. This study can provide insights into solute transport in red soil under low-quality water irrigation, facilitating soil fertility and structure, as well as low-quality water irrigation strategy optimization.

Combined effect of acidification temperature and different acids on microstructure and textural properties of heat and acid-induced milk gels

Heat and acid-induced milk gels, such as Indian Paneer cheese, can serve as a meat substitute in various cuisines due to their non-melting and cookable features. This study investigated the effects of acidification temperature (60, 70, 80, or 90 °C) and different acidifiers (citric, lactic, or hydrochloric acids) on the composition, texture, and microstructure of these gels. Across all acids, increasing the acidification temperature reduced the yield of gel due to lower moisture retention. However, the hardness, springiness, and cohesiveness of the gels increased with temperature, influenced by the rate of protein aggregation and calcium recovery. At high temperatures (e.g., 90 °C), gels prepared by citric acid exhibited greater hardness and cohesiveness, but lower springiness compared to those made with lactic or hydrochloric acid. This effect may be attributed to the formation of a more compact gel network, characterized by fewer pores, and lower water mobility.

Resiliency evaluation of sheltering in a net-zero energy house during summer power outage

This study examines the growing issue of power outages caused by natural disasters and proposes the use of net-zero energy houses (ZEH) as a safe alternative to traditional shelters. A ZEH, equipped with an independent energy system, can maintain essential living standards such as thermal comfort and 24-hour air conditioning during a summer power outage, reducing the risk of heatstroke. The research tested a ZEH in Japan, confirming its ability to support critical household appliances like refrigerators, lighting, and water heaters for up to 72 h. This demonstrates the ZEH's potential for offering safe, comfortable shelter during emergencies while addressing problems like poor sanitation and lack of privacy found in typical shelters. The experimental ZEH is located in Shizuoka, Japan, is a steel structure, and has a floor area of 110.94 m2 and overall heat transmission coefficient (UA) of 0.48 W/m2·K. The ZEH was equipped with a 5.1 kW photovoltaic system and 5.6/11.2 kWh storage battery (BT), which produced an output of up to 2.0/4.0 kVA. A ZEH with a 5.6 kWh BT can provide for ventilation and living/dining room/kitchen air conditioning (AC), refrigerator, television, lighting, mobile phone charging, rice cooker, microwave, electric kettle, and heat pump water heater during a 72-h power outage. The ZEH with a 11.2 kWh BT can also provide bedroom AC and high-load home appliances for lunch and dinner, in addition to a 5.6 kWh BT. The use of AC in a self-supporting circuit maintained the thermal environment at a low heat stroke risk.

Improvement of okara noodle quality by modifying the soluble/insoluble dietary fibre ratio

This study investigated the effect of okara modified through cellulase hydrolysis and extrusion on noodle quality. Modification increased the soluble dietary fibre/insoluble dietary fibre (SDF/IDF) ratio in okara, improved appearance, cooking, and texture, and reduced starch digestibility of okara noodles. The 4.0 % cellulase enzymolysis-extruded okara noodles exhibited the quality closest to that of wheat noodles, with an estimated glycaemic index (eGI) < 55 (low-GI). As the okara SDF/IDF ratio increased, the water mobility of noodles decreased, indicating that an increase in the SDF/IDF ratio reduced competitive water absorption of okara. In addition, increased SDF/IDF ratio increased β-sheet content and promoted the enhanced hydrogen bond interactions between proteins and polymerisation between gliadin and glutenin. Moreover, the microstructure of noodles with a higher SDF/IDF ratio of okara was more continuous and compact, further confirming the promotional effect of okara with a higher SDF/IDF ratio on the quality of okara noodles.

Effects of Moisture Migration and Changes in Gluten Network Structure during Hot Air Drying on Quality Characteristics of Instant Dough Sheets.

The impact of hot air drying temperature on instant dough sheets' qualities was investigated based on water migration and gluten network structure changes. The results revealed that the drying process redistributed the hydrogen proton, with deeply bound water accounting for more than 90%. The T2 value decreased as the drying temperature increased, effectively restricting moisture mobility. Meanwhile, microstructural analysis indicated that instant dough sheets presented porous structures, which significantly reduced the rehydration time of instant dough sheets (p < 0.05). In addition, elevated drying temperatures contributed to the cross-linking of proteins, as evidenced by increased GMP and disulfide bond content (reaching a maximum at 80 °C), which improved the texture and cooking properties. Hence, the water mobility was effectively reduced by controlling the drying temperature. The temperature had a facilitating impact on promoting the aggregation of the gluten network structure, which improved the quality of the instant dough sheets.

Peanut de-oiling at room temperature by micro-aqueous hydration: Co-destabilization driven by oleosome coalescence and protein aggregation

The peanut de-oiling industry currently lacks efficient processing technologies for de-oiling at low or room temperatures. A novel method, micro-aqueous extraction (MAE), offers over 93 % de-oiling efficiency at room temperature and is also effective for other oilseeds like sesame, camellia, and rapeseed. Despite its effectiveness, the exact mechanism behind oleosomes destabilization at a critical hydration level or oil volume fraction (φ ∼ 0.75) is not fully understood. This study investigates how MAE affects peanut oleosome size, paste stability, and the interfacial properties of surfactant proteins. Results showed that micro-aqueous hydration and agitation caused small droplets (85.6 vol% < 10 μm) to coalesce into larger droplets (90.0 vol% > 30 μm) due to press-induced rupture of the liquid film. Simultaneously, agitation decreased water mobility and protein intrinsic fluorescence, while increasing paste viscosity, leading to protein aggregation. This aggregation further promoted oleosome coalescence. Additionally, hydration and agitation weakened the ability of membrane proteins to stabilize oleosomes by increasing interfacial tension and decreasing dilatational storage modulus. The insights into the peanut oleosome destabilization mechanism for MAE provide a foundation for scaling up the process, with the potential to replace current hot and cold pressing techniques.