A proposal for the structuring of water

Photomolecular effect: Visible light interaction with air-water interface

Although water is almost transparent to visible light, we demonstrate that the air-water interface interacts strongly with visible light via what we hypothesize as the photomolecular effect. In this effect, transverse-magnetic polarized photons cleave off water clusters from the air-water interface. We use 14 different experiments to demonstrate the existence of this effect and its dependence on the wavelength, incident angle, and polarization of visible light. We further demonstrate that visible light heats up thin fogs, suggesting that this process can impact weather, climate, and the earth's water cycle and that it provides a mechanism to resolve the long-standing puzzle of larger measured clouds absorption to solar radiation than theory could predict based on bulk water optical constants. Our study suggests that the photomolecular effect should happen widely in nature, from clouds to fogs, ocean to soil surfaces, and plant transpiration and can also lead to applications in energy and clean water.

The Second Derivative of Fullerene C60 (SD-C60) and Biomolecular Machinery of Hydrogen Bonds: Water-Based Nanomedicine

The human body contains 60-70% water, depending on age. As a body fluid, it is not only a medium in which physical and chemical processes take place, but it is also one of the active mediators. Water is the richest substance with non-covalent hydrogen bonds. Water molecules, by themselves (in vacuum), are diamagnetic but when organized into clusters, they become diamagnetic or paramagnetic. Also, biomolecules (DNA, collagen, clathrin, and other proteins) have non-covalent hydrogen bonds in their structure. The interaction, as well as signal transmission, between water and biomolecules is achieved through the vibrations of covalent and non-covalent hydrogen bonds, which determine the state and dynamics of conformational changes in biomolecules. Disruptive conformational changes in biomolecules, cells, and tissues lead to their dysfunctionality, so they are a frequent cause of many disorders and diseases. For example, the rearrangement of hydrogen bonding due to mitochondrial disease mutation in cytochrome bc1 disturbs heme bH redox potential and spin state. In order to prevent and repair the dysfunctional conformational changes, a liquid substance was developed based on the second derivative of the C60 molecule (SD-C60), which has classical and quantum properties. The characterization of SD-C60 by UV-VIS-NIR, FTIR, TEM, and AFM/MFM was performed and it is shown that SD-C60 water layers generate vibrations with near-zero phase dispersion which are transmitted through Fibonacci's water chains to biomolecules. In comparison with previously published SD-C60 derivate (3HFWC, size until 10 nm, and 1-5 water layers), the improved formulation (3HFWC-W, size 10-25 nm, and 6-9 water layers) showed multiplied cytotoxic activity against melanoma cell lines of different aggressiveness. Apart from this, the mode of action was preserved and based on an induction of senescence rather than cell death. Importantly, high selectivity towards malignant phenotypes was detected. Observed effects can be ascribed to a machinery of hydrogen bonds, which are generated in SD-C60 and transmitted through water to biomolecules. This approach may open a new field in science and healthcare-a "water-based nanomedicine".

Plausible photomolecular effect leading to water evaporation exceeding the thermal limit

We report in this work several unexpected experimental observations on evaporation from hydrogels under visible light illumination. 1) Partially wetted hydrogels become absorbing in the visible spectral range, where the absorption by both the water and the hydrogel materials is negligible. 2) Illumination of hydrogel under solar or visible-spectrum light-emitting diode leads to evaporation rates exceeding the thermal evaporation limit, even in hydrogels without additional absorbers. 3) The evaporation rates are wavelength dependent, peaking at 520 nm. 4) Temperature of the vapor phase becomes cooler under light illumination and shows a flat region due to breaking-up of the clusters that saturates air. And 5) vapor phase transmission spectra under light show new features and peak shifts. We interpret these observations by introducing the hypothesis that photons in the visible spectrum can cleave water clusters off surfaces due to large electrical field gradients and quadrupole force on molecular clusters. We call the light-induced evaporation process the photomolecular effect. The photomolecular evaporation might be happening widely in nature, potentially impacting climate and plants' growth, and can be exploited for clean water and energy technologies.

The Effect of Plasma-Treated Water on Microbial Growth and Biosynthesis of Gamma-Decalactones by Yarrowia lipolytica Yeast

In recent years, the production of plasma-treated water (PTW) by low-temperature low-pressure glow plasma (LPGP) has been increasingly gaining in popularity. LPGP-treated water changes its physical and physiochemical properties compared to standard distilled water. In this study, a non-conventional lipolytic yeast species Yarrowia lipolytica was cultivated in culture media based on Nantes plasma water with heightened singlet oxygen content (Nantes PW) or in water treated with low-temperature, low-pressure glow plasma while in contact with air (PWTA) or nitrogen (PWTN). The research aimed to assess the influence of culture conditions on castor oil biotransformation to gamma-decalactone (GDL) and other secondary metabolites in media based on nanowater. The Nantes plasma water-based medium attained the highest concentration of gamma-decalactone (4.81 ± 0.51 g/L at 144 h of culture), maximum biomass concentration and biomass yield from the substrate. The amplified activity of lipases in the nanowater-based medium, in comparison to the control medium, is encouraging from the perspective of GDL biosynthesis, relying on the biotransformation of ricinoleic acid, which is the primary component of castor oil. Although lipid hydrolysis was enhanced, this step seemed not crucial for GDL concentration. Interestingly, the study validates the significance of oxygen in β-oxidation enzymes and its role in the bioconversion of ricinoleic acid to GDL and other lactones. Specifically, media with higher oxygen content (WPTA) and Nantes plasma water resulted in remarkably high concentrations of four lactones: gamma-decalactone, 3-hydroxy-gamma-decalactone, dec-2-en-4-olide and dec-3-en-4-olide.

Questioning rotary functionality in the bacterial flagellar system and proposing a murburn model for motility

Bacterial flagellar system (BFS) was the primary example of a purported 'rotary-motor' functionality in a natural assembly. This mandates the translation of a circular motion of components inside into a linear displacement of the cell body outside, which is supposedly orchestrated with the following features of the BFS: (i) A chemical/electrical differential generates proton motive force (pmf, including a trans-membrane potential, TMP), which is electro-mechanically transduced by inward movement of protons via BFS. (ii) Membrane-bound proteins of BFS serve as stators and the slender filament acts as an external propeller, culminating into a hook-rod that pierces the membrane to connect to a 'broader assembly of deterministically movable rotor'. We had disclaimed the purported pmf/TMP-based respiratory/photosynthetic physiology involving Complex V, which was also perceived as a 'rotary machine' earlier. We pointed out that the murburn redox logic was operative therein. We pursue the following similar perspectives in BFS-context: (i) Low probability for the evolutionary attainment of an ordered/synchronized teaming of about two dozen types of proteins (assembled across five-seven distinct phases) towards the singular agendum of rotary motility. (ii) Vital redox activity (not the gambit of pmf/TMP!) powers the molecular and macroscopic activities of cells, including flagella. (iii) Flagellar movement is noted even in ambiances lacking/countering the directionality mandates sought by pmf/TMP. (iv) Structural features of BFS lack component(s) capable of harnessing/achieving pmf/TMP and functional rotation. A viable murburn model for conversion of molecular/biochemical activity into macroscopic/mechanical outcomes is proposed herein for understanding BFS-assisted motility. HIGHLIGHTSThe motor-like functionalism of bacterial flagellar system (BFS) is analyzedProton/Ion-differential based powering of BFS is unviable in bacteriaUncouplers-sponsored effects were misinterpreted, resulting in a detour in BFS researchThese findings mandate new explanation for nano-bio-mechanical movements in BFSA minimalist murburn model for the bacterial flagella-aided movement is proposedCommunicated by Ramaswamy H. Sarma.

Exploring the Non-Covalent Bonding in Water Clusters

QTAIM and source function analysis were used to explore the non-covalent bonding in twelve different water clusters (H2O)n obtained by considering n = 2–7 and various geometrical arrangements. A total of seventy-seven O−H⋯O hydrogen bonds (HBs) were identified in the systems under consideration, and the examination of the electron density at the bond critical point (BCP) of these HBs revealed the existence of a great diversity of O−H⋯O interactions. Furthermore, the analysis of quantities, such as |V(r)|/G(r) and H(r), allowed a further description of the nature of analogous O−H⋯O interactions within each cluster. In the case of 2-D cyclic clusters, the HBs are nearly equivalent between them. However, significant differences among the O−H⋯O interactions were observed in 3-D clusters. The assessment of the source function (SF) confirmed these findings. Finally, the ability of SF to decompose the electron density (ρ) into atomic contributions allowed the evaluation of the localized or delocalized character of these contributions to ρ at the BCP associated to the different HBs, revealing that weak O−H⋯O interactions have a significant spread of the atomic contributions, whereas strong interactions have more localized atomic contributions. These observations suggest that the nature of the O−H⋯O hydrogen bond in water clusters is determined by the inductive effects originated by the different spatial arrangements of the water molecules in the studied clusters.

Water model for hydrophobic cavities: structure and energy from quantum-chemical calculations

This ab initio study aims to design a series of large water clusters having a hollow clathrate-like cage able to host hydrophobic solutes of various sizes. Starting from the (H₂O)_n (n = 18, 20, 24 and 28) hollow cages, water layers have been added in a stepwise manner in order to model the configuration of water molecules beyond the primary shell. The large (H₂O)₁₀₀, (H₂O)₁₂₀ and (H₂O)₁₄₀ clusters complete the hydrogen bonding network of the cage with optimal and regular tiling of the do-, tetra-decahedron and hexa-decahedron, respectively. This study is corroborated by an investigation of dense water clusters up to the (H₂O)₁₂₃ one, being highly consistent with experimental data on ice concerning the electronic and zero-point energies for aggregate formation at 0 K and enthalpy and entropy at 273 K. The cavity creation profoundly alters the orientation of water molecules compared with those found in dense clusters. Nevertheless, such a large reorganization is necessary to maximize the water-water attraction by making it similar to the one found in dense clusters. The cage formation is an endothermic process; however, the computed values are large compared with previous reports for hydrocarbon aqueous solutions. Larger clusters are required for a more fruitful comparison.

Missing Piece in Colloidal Stability─Morphological Factor of Hydrophobic Nanoparticles

Hydrophobic nanoparticles (NPs) in water were considered unstable because they lack the repulsive electrostatic interaction and steric effect to prevent aggregation. In this study, porous hydrophobic NPs of two star-shaped giant molecules, POSS-(R)₈, were found to be stable in water and able to retain their kinetic stability in a wide range of temperatures, pH values, and ionic strengths. Unlike the solid hydrophobic NPs that aggregate even with the negative zeta potential (ζ) induced by surface-structured hydrogen-bonded (SHB) water, the porous morphology of POSS-(R)₈ NPs reduces the entropically driven hydrophobic effect to prevent aggregation. With the porous morphology, the hydrophobic NPs are stable without the hydrophilic or charged surface functional groups and demonstrate good encapsulation capability. The morphological factor of colloids is thus one of the missing pieces in the theory of colloidal stability that extends our understanding of colloidal science.

The Global Polarity of Alcoholic Solvents and Water - Importance of the Collectively Acting Factors Density, Refractive Index and Hydrogen Bonding Forces

The DHBD quantity represents the hydroxyl group density of alcoholic solvents or water. DHBD is purely physically defined by the product of molar concentration of the solvent (N) and the factor Σn=n×f which reflects the number n and position (f-factor) of the alcoholic OH groups per molecule. Whether the hydroxyl group is either primary, secondary or tertiary is taken into account by f. Σn is clearly linearly correlated with the physical density or the refractive index of the alcohol derivative. Relationships of solvent-dependent UV/Vis absorption energies as ET (30) values, 129 Xe NMR shifts and kinetic data of 2-chloro-2-methylpropane solvolysis with DHBD are demonstrated. It can be shown that the ET (30) solvent parameter reflects the global polarity of the hydrogen bond network rather than specific H-bond acidity. Significant correlations of the log k1 rate constants of the solvolysis reaction of 2-chloro-2-methylpropane with DHBD show the physical reasoning of the approach.

Water clusters and density fluctuations in liquid water based on extended hierarchical clustering methods

The microscopic structures of liquid water at ambient temperatures remain a hot debate, which relates with structural and density fluctuations in the hydrogen bond network. Here, we use molecular dynamics simulations of liquid water to study the properties of three-dimensional cage-like water clusters, which we investigate using extended graph-based hierarchical clustering methods. The water clusters can cover over 95% of hydrogen bond network, among which some clusters maximally encompass thousands of molecules extending beyond 3.0 nm. The clusters imply fractal behaviors forming percolating networks and the morphologies of small and large clusters show different scaling rules. The local favored clusters and the preferred connections between adjacent clusters correspond to lower energy and conformational entropy depending on cluster topologies. Temperature can destroy large clusters into small ones. We show further that the interior of clusters favors high-density patches. The water molecules in the small clusters, inside which are the void regarded as hydrophobic objects, have a preference for being more tetrahedral. Our results highlight the properties and changes of water clusters as the fundamental building blocks of hydrogen bond networks. In addition, the water clusters can elucidate structural and density fluctuations on different length scales in liquid water.

Are cyclic plant and animal behaviours driven by gravimetric mechanical forces?

The celestial mechanics of the Sun, Moon, and Earth dominate the variations in gravitational force that all matter, live or inert, experiences on Earth. Expressed as gravimetric tides, these variations are pervasive and have forever been part of the physical ecology with which organisms evolved. Here, we first offer a brief review of previously proposed explanations that gravimetric tides constitute a tangible and potent force shaping the rhythmic activities of organisms. Through meta-analysis, we then interrogate data from three study cases and show the close association between the omnipresent gravimetric tides and cyclic activity. As exemplified by free-running cyclic locomotor activity in isopods, reproductive effort in coral, and modulation of growth in seedlings, biological rhythms coincide with temporal patterns of the local gravimetric tide. These data reveal that, in the presumed absence of rhythmic cues such as light and temperature, local gravimetric tide is sufficient to entrain cyclic behaviour. The present evidence thus questions the phenomenological significance of so-called free-run experiments.

Hydrogen-Bonding 2D Coordination Polymer for Enzyme-Free Electrochemical Glucose Sensing

Regular detection of blood glucose levels is a critical indicator for effective diabetes management. Owing to the intrinsic highly sensitive nature of enzymes, the performance of enzymatic glucose sensors is...

Bipolar Membrane and Water Splitting in Electrodialysis

The traditional view of the conductivity of electrolytes is based on the mobility of ions in an electric field. A new concept of water conductivity introduces an electron–hole mechanism known from semiconductor theory. The electrolyte ions in the hydrogen bond network of water imitate the structure of a doped silicon lattice. The source of the current carriers is the electrode reaction generating H+ and OH− ions. The continuity of current flow is provided through the electron–hole mechanism, and the movement of electrolyte ions is only a side process. Bipolar membrane in the semiconductor approach is an electrochemical diode forward biased. Generation of large amounts of H+ and OH− has to be considered as a result of current flow and does not require any increase in the water dissociation rate. Bipolar membranes are essential in electrodialysis stacks for the recovery of acids and bases by salt splitting.

Graphic Abstract

Effect of Waters Enriched in O2 by Injection or Electrolysis on Performance and the Cardiopulmonary and Acid-Base Response to High Intensity Exercise

Several brands of water enriched with O₂ (O₂-waters) are commercially available and are advertised as wellness and fitness waters with claims of physiological and psychological benefits, including improvement in exercise performance. However, these claims are based, at best, on anecdotal evidence or on a limited number of unreliable studies. The purpose of this double-blind randomized study was to compare the effect of two O₂-waters (~110 mg O₂·L^-1) and a placebo (10 mg O₂·L^-1, i.e., close to the value at sea level, 9-12 mg O₂·L^-1) on the cardiopulmonary responses and on performance during high-intensity exercise. One of the two O₂-waters and the placebo were prepared by injection of O₂. The other O₂-water was enriched by an electrolytic process. Twenty male subjects were randomly allocated to drink one of the three waters in a crossover study (2 L·day^-1 × 2 days and 15 mL·kg^-1 90 min before exercise). During each exercise trial, the subjects exercised at 95.9 ± 4.7% of maximal workload to volitional fatigue. Exercise time to exhaustion and the cardiopulmonary responses, arterial lactate concentration and pH were measured. Oxidative damage to proteins, lipids and DNA in blood was assessed at rest before exercise. Time to exhaustion (one-way ANOVA) and the responses to exercise (two-way ANOVA [Time; Waters] with repeated measurements) were not significantly different among the three waters. There was only a trend (p = 0.060) for a reduction in the time constant of the rapid component of VO₂ kinetics with the water enriched in O₂ by electrolysis. No difference in oxidative damage in blood was observed between the three waters. These results suggest that O₂-water does not speed up cardiopulmonary response to exercise, does not increase performance and does not trigger oxidative stress measured at rest.

Thermally Driven Transformation of Water Clustering Structures at Self-Assembled Monolayers

Water clustering structures are considered to play key roles in various temperature-dependent life activities. However, our fundamental understanding of the temperature-dependent water structures remains murky because of the limits of the real-time and real-condition monitoring techniques at the molecular level. We propose an in situ ATR-IR approach combining Gaussian fitting to qualitatively and quantitatively explore the temperature-dependent structural stability and transformation of the three water components, multimer water (MW), intermediate water (IW), and network water (NW), on interfaces with different wettabilities. Our results show that the transformation between NW and IW/MW will occur with a change in temperature. This conversion process shows reversibility on hydrophilic Au NPs film/ZnSe, while it is irreversible on a hydrophobic mercaptohexane self-assembled monolayer due to the irreversibility of the monolayer structure and the hydrophobic confinement effect. The established approach enables us to explore the change in the water properties at any interfaces upon external stimuli.

Nonclinical research areas of future importance for clinical therapies: Exploring the concepts of nonlinearity in dentistry

Linear system analysis has been dominating medical and dental research, and most of the research achievements in these fields have come from applying a reductionist view of nature. However, biologic systems are fundamentally nonlinear with highly composite dynamics made up of numerous interacting elements and feedback loops, therefore studying them as linear models may not result in an accurate representation of their true features. The authors reviewed and utilized some of the principles of chaos and nonlinearity and extended them to clinical dentistry, from cracked tooth and flare-up after root canal procedures to the outcome of clinical treatments. Utilization of the concepts of chaos and sensitive dependence on initial conditions, and the concepts of self-organization, stigmergy, and fractals may help us to understand some of the puzzles that have not been solved by conventional linear models. The goal of this paper is to present some areas within nonclinical research that we believe will have important roles in the development of future clinical examination methods and therapies.

Microwave Irradiation in Technologies of Wastewater and Wastewater Sludge Treatment: A Review

Every year, the human impact on the world’s water sources becomes more pronounced. One of the triggers to this increase is the use of ineffective wastewater and sludge treatment systems. Recently, the number of studies of microwave processing in handling liquid municipal and industrial waste has increased. This paper discusses heat treatment, change in properties, decomposition of substances, removal of metals, demulsification, pyrolysis, biogas processing, disinfection, and other topics. The findings of European, Chinese, Russian, and other authors are summarised and presented in this review. In addition, the most notable Russian patents for microwave installations/devices and reactors suitable for a wide variety of applications are discussed. In this article, the authors look at microwave wastewater and sludge treatment from the perspective of practical application in various fields of human economic activity.

Structured water: effects on animals

This review focuses on the effects of structured water (SW) on animals when it is consumed on a daily basis. SW is liquid water that is given altered H-bonding structure by treatment with various forms of energy including magnetic fields and light. While most of the research has been conducted on 'magnetized' water, which has structure of short duration, recent research has examined effects of a SW with stability of at least 3.5 mo. A variety of laboratory and farm animals have been studied over the past 20 yr. Consistent (3 or more studies) responses among animals consuming SW for 1 mo or more include increased rate of growth, reduced markers of oxidative stress, improved glycemic and insulinemic responses in diabetics, improved blood lipid profile, improved semen and spermatozoa quality, and increased tissue conductivity as measured using bioelectrical impedance analysis. While it is known that fluids in and around cells and molecules are structured, it remains unknown if this endogenous water structuring is influenced by drinking SWs. The mechanisms by which SW affects biological systems are unknown and require investigation. Effects of SW, when taken up by biological systems, are likely associated with altered water structuring around biological surfaces, such as proteins and membranes.

Generation of Photopolymerized Microparticles Based on PEGDA Using Microfluidic Devices. Part 1. Initial Gelation Time and Mechanical Properties of the Material

Photopolymerized microparticles are made of biocompatible hydrogels like Polyethylene Glycol Diacrylate (PEGDA) by using microfluidic devices are a good option for encapsulation, transport and retention of biological or toxic agents. Due to the different applications of these microparticles, it is important to investigate the formulation and the mechanical properties of the material of which they are made of. Therefore, in the present study, mechanical tests were carried out to determine the swelling, drying, soluble fraction, compression, cross-linking density (Mc) and mesh size (ξ) properties of different hydrogel formulations. Tests provided sufficient data to select the best formulation for the future generation of microparticles using microfluidic devices. The initial gelation times of the hydrogels formulations were estimated for their use in the photopolymerization process inside a microfluidic device. Obtained results showed a close relationship between the amount of PEGDA used in the hydrogel and its mechanical properties as well as its initial gelation time. Consequently, it is of considerable importance to know the mechanical properties of the hydrogels made in this research for their proper manipulation and application. On the other hand, the initial gelation time is crucial in photopolymerizable hydrogels and their use in continuous systems such as microfluidic devices.

Exclusion Zone Phenomena in Water-A Critical Review of Experimental Findings and Theories

The existence of the exclusion zone (EZ), a layer of water in which plastic microspheres are repelled from hydrophilic surfaces, has now been independently demonstrated by several groups. A better understanding of the mechanisms which generate EZs would help with understanding the possible importance of EZs in biology and in engineering applications such as filtration and microfluidics. Here we review the experimental evidence for EZ phenomena in water and the major theories that have been proposed. We review experimental results from birefringence, neutron radiography, nuclear magnetic resonance, and other studies. Pollack theorizes that water in the EZ exists has a different structure than bulk water, and that this accounts for the EZ. We present several alternative explanations for EZs and argue that Schurr's theory based on diffusiophoresis presents a compelling alternative explanation for the core EZ phenomenon. Among other things, Schurr's theory makes predictions about the growth of the EZ with time which have been confirmed by Florea et al. and others. We also touch on several possible confounding factors that make experimentation on EZs difficult, such as charged surface groups, dissolved solutes, and adsorbed nanobubbles.

Water is a biomarker of changes in the cellular environment in live animals

The biological processes that are associated with the physiological fitness state of a cell comprise a diverse set of molecular events. Reactive oxygen species (ROS), mitochondrial dysfunction, telomere shortening, genomic instability, epigenetic changes, protein aggregation, and down-regulation of quality control mechanisms are all hallmarks of cellular decline. Stress-related and decline-related changes can be assayed, but usually through means that are highly disruptive to living cells and tissues. Biomarkers for organismal decline and aging are urgently needed for diagnostic and drug development. Our goal in this study is to provide a proof-of-concept for a non-invasive assay of global molecular events in the cytoplasm of living animals. We show that Microwave Dielectric Spectroscopy (MDS) can be used to determine the hydration state of the intracellular environment in live C. elegans worms. MDS spectra were correlative with altered states in the cellular protein folding environment known to be associated with previously described mutations in the C. elegans lifespan and stress-response pathways.

Structure and Physicochemical Properties of Water Treated under Nitrogen with Low-Temperature Glow Plasma

Water treated with low-temperature, low-pressure glow plasma (GP) in contact with air stimulates various microorganisms, the growth of various plants and provides healthy breeding of various animals. In this paper, we present water treated with GP under oxygen-free nitrogen. It is potentially suitable for breeding anaerobic microorganisms, and increasing the crops of plants utilizing atmospheric nitrogen. Deionized water saturated with oxygen-free nitrogen was treated for 5 to 90 min with low-temperature glow plasma (GP). That operation produced nitrogen in various exited states depending on the treatment time. These excited nitrogen molecules built aqueous clathrates around them. The number and structure of those clathrates depended on the time of the treatment with GP. In terms of mass, density, pH, conductivity, surface tension, Ultraviolet-Visible (UV-VIS), Fourier Transformation Infrared (FTIR), Raman and Electron Spin Resonance (ESR) spectra as well as Differential Scanning Calorimetry (DSC), the macrostructure of water saturated with nitrogen treated with GP strongly depended on the treatment time. Based on the entropy criterion, the macrostructure formed on 30 and 5 min treatment was the most and least organized, respectively.

Thermophoresis of biological and biocompatible compounds in aqueous solution

With rising popularity of microscale thermophoresis for the characterisation of protein-ligand binding reactions and possible applications in microfluidic devices, there is a growing interest in considering thermodiffusion in the context of life sciences. But although the understanding of thermodiffusion in non-polar mixtures has grown rapidly in recent years, predictions for associated mixtures like aqueous solutions remain challenging. This review aims to give an overview of the literature on thermodiffusion in aqueous systems, show the difficulties in theoretical description that arise from the non-ideal behaviour of water-mixtures, and highlight the relevance of thermodiffusion in a biological context. We find that the thermodiffusion in aqueous systems is dominated by contributions from heat of transfer, hydrogen bond interactions and charge effects. However, the separation of these effects is often difficult, especially in case of biological systems where a systematic exclusion of contributions may not be feasible.

NOx Adsorption and Optical Detection in Rare Earth Metal-Organic Frameworks

Acid gases (e.g., NO_x and SO_x), commonly found in complex chemical and petrochemical streams, require material development for their selective adsorption and removal. Here, we report the NO_x adsorption properties in a family of rare earth (RE) metal-organic frameworks (MOFs) materials. Fundamental understanding of the structure-property relationship of NO_x adsorption in the RE-DOBDC materials platform was sought via a combined experimental and molecular modeling study. No structural change was noted following humid NO_x exposure. Density functional theory (DFT) simulations indicated that H₂O has a stronger affinity to bind with the metal center than NO₂, while NO₂ preferentially binds with the DOBDC ligands. Further modeling results indicate no change in binding energy across the RE elements investigated. Also, stabilization of the NO₂ and H₂O molecules following adsorption was noted, predicted to be due to hydrogen bonding between the framework ligands and the molecules and nanoconfinement within the MOF structure. This interaction also caused distinct changes in emission spectra, identified experimentally. Calculations indicated that this is due to the adsorption of NO₂ molecules onto the DOBDC ligand altering the electronic transitions and the resulting photoluminescent properties, a feature that has potential applications in future sensing technologies.

Continuous noninvasive glucose monitoring; water as a relevant marker of glucose uptake in vivo

With diabetes set to become the number 3 killer in the Western hemisphere and proportionally growing in other parts of the world, the subject of noninvasive monitoring of glucose dynamics in blood remains a "hot" topic, with the involvement of many groups worldwide. There is a plethora of techniques involved in this academic push, but the so-called multisensor system with an impedance-based core seems to feature increasingly strongly. However, the symmetrical structure of the glucose molecule and its shielding by the smaller dipoles of water would suggest that this option should be less enticing. Yet there is enough phenomenological evidence to suggest that impedance-based methods are truly sensitive to the biophysical effects of glucose variations in the blood. We have been trying to answer this very fundamental conundrum: "Why is impedance or dielectric spectroscopy sensitive to glucose concentration changes in the blood and why can this be done over a very broad frequency band, including microwaves?" The vistas for medical diagnostics are very enticing. There have been a significant number of papers published that look seriously at this problem. In this review, we want to summarize this body of research and the underlying mechanisms and propose a perspective toward utilizing the phenomena. It is our impression that the current world view on the dielectric response of glucose in solution, as outlined below, will support the further evolution and implementation toward practical noninvasive glucose monitoring solutions.

Pártay L. Thermodynamics and the potential energy landscape: case study of small water clusters

We investigated the structure and the thermodynamic properties of small water clusters with the nested sampling computational technique, using two different water models, the coarse-grained mW (up to 25 molecules) and the flexible version of TIP3P (up to 16 molecules).

Bio-soliton model that predicts non-thermal electromagnetic frequency bands, that either stabilize or destabilize living cells

Solitons, as self-reinforcing solitary waves, interact with complex biological phenomena such as cellular self-organization. A soliton model is able to describe a spectrum of electromagnetism modalities that can be applied to understand the physical principles of biological effects in living cells, as caused by endogenous and exogenous electromagnetic fields and is compatible with quantum coherence. A bio-soliton model is proposed, that enables to predict which eigen-frequencies of non-thermal electromagnetic waves are life-sustaining and which are, in contrast, detrimental for living cells. The particular effects are exerted by a range of electromagnetic wave eigen-frequencies of one-tenth of a Hertz till Peta Hertz that show a pattern of 12 bands, and can be positioned on an acoustic reference frequency scale. The model was substantiated by a meta-analysis of 240 published articles of biological electromagnetic experiments, in which a spectrum of non-thermal electromagnetic waves were exposed to living cells and intact organisms. These data support the concept of coherent quantized electromagnetic states in living organisms and the theories of Fröhlich, Davydov and Pang. It is envisioned that a rational control of shape by soliton-waves and related to a morphogenetic field and parametric resonance provides positional information and cues to regulate organism-wide systems properties like anatomy, control of reproduction and repair.

Exploring the behaviour of water in glycerol solutions by using delayed luminescence

The crucial role of water in the engine of life have encouraged many researchers in studying, both theoretically and experimentally, the possible "structure" of water. Many properties of water have been related to the interplay between two distinct and interconverting structural species, namely the low-density water (LDW) and the high-density water (HDW). Supported by the results obtained with other aqueous solutions, this paper deals with the possibility of using the ultra-weak delayed luminescence (DL) to investigate water structuring in a mixture with glycerol, characterized only by hydrogen bonds between the various molecules. Spectral and temporal characteristics of DL decays give information on the two components of the mixture, by evidencing the contribution of water at glycerol concentrations close to the values used in cryopreservation. DL results have shown a correlation with LDW clusters size as determined by other researchers on the basis of neutron diffraction experiments and computational modelling, as reported in Literature.

Mannose Surfaces Exhibit Self-Latching, Water Structuring, and Resilience to Chaotropes: Implications for Pathogen Virulence

Several viral and fungal pathogens, including HIV, SARS, Dengue, Ebola, and Cryptococcus neoformans, display a preponderance of mannose residues on their surface, particularly during the infection cycle or in harsh environments. The innate immune system, on the other hand, abounds in mannose receptors which recognize mannose residues on pathogens and trigger their phagocytosis. We pose the question if there is an advantage for pathogens to display mannose on their surface, despite these residues being recognized by the immune system. The surface properties and interactions of opposing monolayers of mannobiose (disaccharide of mannose) were probed using atomic force spectroscopy. Unlike its diastereoisomer lactose, mannobiose molecules exhibited lateral packing interactions that manifest on the surface scale as a self-recognizing latch. A break-in force is required for opposing surfaces to penetrate and a breakout (or self-adhesion force) of similar magnitude is required for penetrated surfaces to separate. A hierarchy of self-adhesion forces was distinguished as occurring at the single residue (∼25 pN), cluster (∼250 pN), monolayer (∼1.1 nN), and supramonolayer level. The break-in force and break-out force appear resilient to the presence of simple chaotropes that attenuate a layer of structured water around the mannose surface. The layer of structured water otherwise extends to distances several times longer than a mannobiose residue, indicating a long-range propagation of the hydrogen bonding imposed by the residues. The span of the structured water increases with the velocity of an approaching surface, similar to shear thickening, but fissures at higher approach velocities. Our studies suggest that mannose residues could guide interpathogen interactions, such as in biofilms, and serve as a moated fortress for pathogens to hide behind to resist detection and harsh environments.

Microwave dielectric spectroscopy study of water dynamics in normal and contaminated raw bovine milk

The role of water in bovine milk is more complicated than that of a background solvent. To understand the interaction between water and the constituents of milk, an extensive dielectric study of the γ-dispersion of raw bovine milk was carried out over the frequency range 0.1-50GHz and the interval of temperatures (10°C-42°C). Samples were provided by utilizing an extended donor pool. The results reveal that the temperature dependence of the characteristic relaxation times is described by the Arrhenius law. Furthermore, it conforms to a Meyer-Neldel compensation, whereby the pre-factor of the relaxation times is dependent on the activation energy. This entropy/enthalpy compensation is traced to the interaction between bulk water dynamic clusters and other milk constituents. A statistical correlation between the Somatic Cell Count, a traditional measure of milk quality, and the relaxation times is provided as well, opening new vistas for the industrial classification of milk.

How water manifests the structural regimes in ionic liquids

Ionic liquids (ILs) are being considered as greener alternatives to the conventional organic solvents. However, highly viscous nature of ILs often limits their applications. Hence studies on IL/water binary mixtures have received tremendous attention. These mixtures exhibit much lower viscosity, but almost similar density, compressibility and other properties as that of the neat ILs, up to certain water content. Hence, determining the IL-water ratio till which the solution behaves like IL and subsequently changes to a state of solute IL dissolved in continuous water phase is of paramount importance. Noting the very different and characteristic behaviours of neat ILs and pure water over a temperature range, herein, we measured the various thermophysical properties of the binary mixtures of tetramethylguanidinium benzoate/water and tetramethylguanidinium salicylate/water with water content varying from 20 wt% to 95 wt% for a temperature range of 298 K to 343 K. The results show that similar to neat ILs, the measured densities and compressibility of these mixtures display a linear change, and viscosity decreases rapidly as temperature is increased for water content up to 50 wt%. At higher water concentrations, the measured density and compressibility exhibit nonlinear behaviour and the decrease in viscosity with increased temperature is minute, mimicking the behaviour of bulk water. MD simulations were carried out to explain the experimental observations. Simulation results show a greater temperature-induced disintegration of IL ion-water interactions in dense systems, explaining the rapid decay of the properties with temperature. The results also exhibit the presence of a neat, IL-like, H-bond mediated expanded structure in concentrated solution versus a collapsed IL structure in dilute solution.

A neutron spin echo study of low-temperature water confined in the spherical silica pores of SBA-16

The dynamic properties of heavy water (D₂O) and light water (H₂O) confined in porous silica SBA-16 were studied over a temperature range of 210–290 K by neutron spin echo measurements.

Giant Pockels effect of polar organic solvents and water in the electric double layer on a transparent electrode

The Pockels effect of polar organic solvents and water within the electric double layer on an ITO electrode is studied to find that water has the largest Pockels coefficient, followed in order by methanol, ethanol, and dimethyl sulfoxide.

Delayed luminescence induced by complex domains in water and in TEOS aqueous solutions

Many recent studies on water have conjectured a complex structure composed of hydrogen bonded low- and high-density domains. In this work the structure of pure water and aqueous solutions of silica gel (TEOS) has been investigated by using delayed luminescence, which has previously shown a significant increase in aqueous salt solutions where low-density domain formation is expected. Photon emission shows an Arrhenius trend with an activation energy in water-TEOS solutions larger than in pure water and salt-water solutions. Moreover, delayed photon emission decay shows an intrinsic lifetime of about 5 μs both in solutions and in pure water that, along with secondary lifetimes induced by the presence of TEOS, could be related to the formation of different domains.

The Opposite Effect of Metal Ions on Short-/Long-Range Water Structure: A Multiple Characterization Study

Inorganic electrolyte solutions are very important in our society as they dominate many biochemical and geochemical processes. Herein, an in-depth study was performed to illustrate the ion-induced effect on water structure by coupling NMR, viscometer, Raman and Molecular Dynamic (MD) simulations. The NMR coefficient (B_NMR) and diffusion coefficient (D) from NMR, and viscosity coefficient (B_vis) from a viscometer all proved that dissolved metal ions are capable of enhancing the association degree of adjacent water molecules, and the impact on water structure decreased in the order of Cr³⁺ > Fe³⁺ > Cu²⁺ > Zn²⁺. This regularity was further evidenced by Raman analysis; however, the deconvoluted Raman spectrum indicated the decrease in high association water with salt concentration and the increase in low association water before 200 mmol·L⁻¹. By virtue of MD simulations, the opposite changing manner proved to be the result of the opposite effect on short-/long-range water structure induced by metal ions. Our results may help to explain specific protein denaturation induced by metal ions.