Energy Electronegativity and Chemical Bonding.

Historical development of the concept of electronegativity (EN) and its significance and prospects for physical and structural chemistry are discussed. The current cutting-edge results are reviewed: new methods of determining the ENs of atoms in solid metals and of bond polarities and effective atomic charges in molecules and crystals. The ENs of nanosized elements are calculated for the first time, enabling us to understand their unusual reactivity, particularly the fixation of N2 by nanodiamond. Bond polarities in fluorides are also determined for the first time, taking into account the peculiarities of the fluorine atom's electronic structure and its electron affinity.

Effect of Filtrated Osmotic Solution Based on Concentrated Chokeberry Juice and Mint Extract on the Drying Kinetics, Energy Consumption and Physicochemical Properties of Dried Apples.

BACKGROUND: Filtration of osmotic solution affects selective penetration during osmotic dehydration (OD), and after drying is finished, this can influence the chemical composition of the material, which is also modified by OD. METHODS: Osmotic dehydration was carried out in filtrated and non-filtrated concentrated chokeberry juice with the addition of mint infusion. Then, this underwent convective drying, vacuum-microwave drying and combined convective pre-drying, followed by vacuum-microwave finishing drying. Drying kinetics were presented and mathematical models were selected. The specific energy consumption for each drying method was calculated and the energy efficiency was determined. RESULTS AND DISCUSSION: The study revealed that filtration of osmotic solution did not have significant effect on drying kinetics; however, it affected selective penetration during OD. The highest specific energy consumption was obtained for the samples treated by convective drying (CD) (around 170 kJ·g-1 fresh weight (fw)) and the lowest for the samples treated by vacuum-microwave drying (VMD) (around 30 kJ·g-1 fw), which is due to the differences in the time of drying and when these methods are applied. CONCLUSIONS: Filtration of the osmotic solution can be used to obtain the desired material after drying and the VMD method is the most appropriate considering both phenolic acid content and the energy aspect of drying.

Some Aspects of the Liquid Water Thermodynamic Behavior: From The Stable to the Deep Supercooled Regime.

Liquid water is considered to be a peculiar example of glass forming materials because of the possibility of giving rise to amorphous phases with different densities and of the thermodynamic anomalies that characterize its supercooled liquid phase. In the present work, literature data on the density of bulk liquid water are analyzed in a wide temperature-pressure range, also including the glass phases. A careful data analysis, which was performed on different density isobars, made in terms of thermodynamic response functions, like the thermal expansion αP and the specific heat differences CP-CV, proves, exclusively from the experimental data, the thermodynamic consistence of the liquid-liquid transition hypothesis. The study confirms that supercooled bulk water is a mixture of two liquid "phases", namely the high density (HDL) and the low density (LDL) liquids that characterize different regions of the water phase diagram. Furthermore, the CP-CV isobars behaviors clearly support the existence of both a liquid-liquid transition and of a liquid-liquid critical point.

Influence of physiochemical properties on the subcutaneous absorption and bioavailability of monoclonal antibodies.

Many therapeutic monoclonal antibodies (mAbs) were initially developed for intravenous (IV) administration. As a means to improve mAb drug-ability and the patient experience, subcutaneous (SC) administration is an increasingly important delivery route for mAbs. Unlike IV administration, bioavailability limitations for antibodies have been reported following SC injection and can dictate whether a mAb is administered via this parenteral route. The SC bioavailability of antibodies has been difficult to predict, and it can be variable and partial, with values ranging from ~50% to 100%. The mechanisms leading to the incomplete bioavailability of some mAbs relative to others are not well understood. There are some limited data that suggest the physiochemical properties inherent to a mAb can contribute to its SC absorption, bioavailability, and in vivo fate. In this study, we evaluated the integrated influence of multiple mAb physiochemical factors on the SC absorption and bioavailability of six humanized mAbs in both rats and cynomolgus monkeys. We demonstrate the physiochemical properties of mAbs are critical to their rate and extent of SC absorption. The combination of high positive charge and hydrophobic interaction significantly reduced the rate of the evaluated mAb's SC absorption and bioavailability. Reduction or balancing of both these attributes via re-engineering the mAbs restored desirable properties of the molecules assessed. This included reduced association with SC tissue, improvements in mAb absorption from the SC space and overall SC bioavailability. Our findings point to the importance of evaluating the relative balance between various physiochemical factors, including charge, hydrophobicity, and stability, to improve the SC drug-ability of mAbs for selecting or engineering mAbs with enhanced in vivo absorption and bioavailability following SC administration.

Insights into the mechanism of coreactant electrochemiluminescence facilitating enhanced bioanalytical performance.

Electrochemiluminescence (ECL) is a powerful transduction technique with a leading role in the biosensing field due to its high sensitivity and low background signal. Although the intrinsic analytical strength of ECL depends critically on the overall efficiency of the mechanisms of its generation, studies aimed at enhancing the ECL signal have mostly focused on the investigation of materials, either luminophores or coreactants, while fundamental mechanistic studies are relatively scarce. Here, we discover an unexpected but highly efficient mechanistic path for ECL generation close to the electrode surface (signal enhancement, 128%) using an innovative combination of ECL imaging techniques and electrochemical mapping of radical generation. Our findings, which are also supported by quantum chemical calculations and spin trapping methods, led to the identification of a family of alternative branched amine coreactants, which raises the analytical strength of ECL well beyond that of present state-of-the-art immunoassays, thus creating potential ECL applications in ultrasensitive bioanalysis.

Concentrated protein solutions investigated using acoustic levitation and small-angle X-ray scattering.

An acoustically levitated droplet has been used to collect synchrotron SAXS data on human serum albumin protein solutions up to a protein concentration of 400 mg ml-1. A careful selection of experiments allows for fast data collection of a large amount of data, spanning a protein concentration/solvent concentration space with limited sample consumption (down to 3 µL per experiment) and few measurements. The data analysis shows data of high quality that are reproducible and comparable with data from standard flow-through capillary-based experiments. Furthermore, using this methodology, it is possible to achieve concentrations that would not be accessible by conventional cells. The protein concentration and ionic strength parameter space diagram may be covered easily and the amount of protein sample is significantly reduced (by a factor of 100 in this work). Used in routine measurements, the benefits in terms of protein cost and time spent are very significant.

A protein corona primer for physical chemists.

Nanoparticles present in any biological environment are exposed to extracellular proteins. These proteins adsorb on the surface of the nanoparticle forming a "protein corona." These proteins control the interaction of nanoparticles with cells. The interaction of proteins with the nanoparticle surface is governed by physical chemistry. Understanding this process requires spectroscopy, microscopy, and computational tools that are familiar to physical chemists. This perspective provides an overview of the protein corona along with two future directions: first, the need for new computational approaches, including machine learning, to predict corona formation and second, the extension of protein corona studies to more complex environments ranging from lung fluids to waste water treatment.

[Prediction of Wettability and Adhesion of Lotion to Skin Based on the OWRK Method].

In this study, we propose a new technique for evaluating wetting and adhesion of lotions to skin using surface tension measurements, contact angle measurements and calculations based on the Owens-Wendt-Rabel-Kaelble (OWRK) method. Three prescription lotions (Napageln® Lotion 3%, Sumilu® Lotion 3% and Felbinac Lotion 3% ï½¢Rakool｣） and two over-the-counter lotions (Feitas® Lotion and Salomethyl® FB Lotion α) were used. Based on the dispersive and polar components of the surface free energy of Yucatan micro pig (YMP) skin, isograms of contact angle (wetting envelope) and adhesion work of the YMP skin surface were constructed. Plotting the surface tension and its polar component of lotions on this isogram revealed that it is possible to predict the wettability and adhesion of lotions to YMP skin. Such diagrams can be easily constructed even using the surface free energy of other types of skin, such as that of humans and hairless mice. This evaluation method may be applicable to other external use medicines.

Role of sulfur in proton-induced collisions of RNA prebiotic precursors.

A main objective in the synthesis of prebiotic compounds is to remain consistent with reasonable geochemical scenarios, while avoiding concomitant formation of undesirable by-products. In this context, 2-aminothiazole has shown enhanced selectivity in the addition reaction with sugars promoting interest in this sulfur species compared to its oxygenated analogue, 2-aminooxazole. More generally, the role of sulfur in prebiotic chemistry needs to be widely investigated with regard to the numerous sulfur-containing molecules detected recently in different astrophysical environments. However, in parallel to the problematic formation of building blocks of life, how prebiotic molecules could survive under extreme astrophysical conditions remains an open question. Intense UV radiation or ion bombardment may indeed lead to fragmentation and the specific behaviour of sulfur compounds has to be addressed. Focusing on its potentiality in prebiotic multistep synthesis, a detailed analysis of the proton impact on 2-aminothiazole has been investigated theoretically in a wide collision energy range chosen to model various astrophysical environments. The comparison with its oxygenated analogue may suggest qualitative trends on their respective stability under such processes which could be of crucial interest for prebiotic synthesis.

Theory of Diffusion-Influenced Reaction Networks.

A formalism is developed to describe how diffusion alters the kinetics of coupled reversible association-dissociation reactions in the presence of conformational changes that can modify the reactivity. The major difficulty in constructing a general theory is that, even to the lowest order, diffusion can change the structure of the rate equations of chemical kinetics by introducing new reaction channels (i.e., modifies the kinetic scheme). Therefore, the right formalism must be found that allows the influence of diffusion to be described in a concise and elegant way for networks of arbitrary complexity. Our key result is a set of non-Markovian rate equations involving stoichiometric matrices and net reaction rates (fluxes), in which these rates are coupled by a time-dependent pair association flux matrix, whose elements have a simple physical interpretation. Specifically, each element is the probability density that an isolated pair of reactants irreversibly associates at time t via one reaction channel on the condition that it started out with the dissociation products of another (or the same) channel. In the Markovian limit, the coupling of the chemical rates is described by committors (or splitting/capture probabilities). The committor is the probability that an isolated pair of reactants formed by dissociation at one site will irreversibly associate at another site rather than diffuse apart. We illustrate the use of our formalism by considering three reversible reaction schemes: (1) binding to a single site, (2) binding to two inequivalent sites, and (3) binding to a site whose reactivity fluctuates. In the first example, we recover the results published earlier, while in the second one we show that a new reaction channel appears, which directly connects the two bound states. The third example is particularly interesting because all species become coupled and an exchange-type bimolecular reaction appears. In the Markovian limit, some of the diffusion-modified rate constants that describe new transitions become negative, indicating that memory effects cannot be ignored.

Report-Physicochemical and Antimicrobial properties of canola (Brassica napus L.) seed oil.

Canola oil has been used in the Pakistan for the treatment of various diseases and skin infections. Oil was extracted with n-hexane from the seeds of canola (Brassica napus L.) and was evaluated for free fatty acid value. Four microorganisms namely; Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas originals, and Klebsiella pneumonia, has known to cause some infections treatable with these oils were investigated. The results showed that all oil shown inhibitory effects against Klebsiella pneumoniae, Staphylococcus epidermidis, and Pseudomonas originals but no inhibitory effects was found against Staphylococcus aureus.

Reversible Interacting-Particle Reaction Dynamics.

Interacting-particle reaction dynamics (iPRD) simulates the spatiotemporal evolution of particles that experience interaction forces and can react with one another. The combination of interaction forces and reactions enables a wide range of complex reactive systems in biology and chemistry to be simulated, but gives rise to new questions such as how to evolve the dynamical equations in a computationally efficient and statistically correct manner. Here we consider reversible reactions such as A + B ⇄ C with interacting particles and derive expressions for the microscopic iPRD simulation parameters such that desired values for the equilibrium constant and the dissociation rate are obtained in the dilute limit. We then introduce a Monte Carlo algorithm that ensures detailed balance in the iPRD time-evolution (iPRD-DB). iPRD-DB guarantees the correct thermodynamics at all concentrations and maintains the desired kinetics in the dilute limit, where chemical rates are well-defined and kinetic measurement experiments usually operate. We show that in dense particle systems, the incorporation of detailed balance is essential to obtain physically realistic solutions. iPRD-DB is implemented in ReaDDy 2.

The Clinical Applications of Polymer Gel Dosimetry Using MRI.

Polymer gel dosimeters are devices that utilize the radiation-induced polymerization reactions of vinyl monomers in a gel to store information of radiation dose. They have some advantages over other dosimeters as the visual conformation and the direct read-out of three-dimensional (3D) radiation dose information for the dosimetric verification of intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and stereotactic radiotherapy (SRT) with steep dose gradients. In this report, the dosimetric uncertainties and potential for clinical applications of polymer gel dosimetry by the in-house developed 3D dose verification system for IMRT and VMAT QA is outlined.

From 50 Years Ago, the Birth of Modern Liquid-State Science.

The story told in this autobiographical perspective begins 50 years ago, at the 1967 Gordon Research Conference on the Physics and Chemistry of Liquids. It traces developments in liquid-state science from that time, including contributions from the author, and especially in the study of liquid water. It emphasizes the importance of fluctuations and the challenges of far-from-equilibrium phenomena.

Physical Chemistry of Bile: Detailed Pathogenesis of Cholelithiasis.

Despite the overwhelming prevalence of cholelithiasis, many health care professionals are not familiar with the basic pathophysiology of gallstone formation. This article provides an overview of the biochemical pathways related to bile, with a focus on the physical chemistry of bile. We describe the important factors in bile synthesis and secretion that affect the composition of bile and consequently its liquid state. Within this biochemical background lies the foundation for understanding the clinical and sonographic manifestation of cholelithiasis, including the pathophysiology of cholesterol crystallization, gallbladder sludge, and gallstones. There is a brief discussion of the clinical manifestations of inflammatory and obstructive cholestasis and the impact on bile metabolism and subsequently on liver function tests. Despite being the key modality in diagnosing cholelithiasis, ultrasound has a limited role in the characterization of stone composition.

Signal and binding. I. Physico-chemical response to macromolecule-ligand interactions.

Obtaining a detailed knowledge about energetics of ligand-macromolecule interactions is a prerequisite for elucidation of the nature, behavior, and activities of the formed complexes. The most commonly used methods in characterizing molecular interactions are physico-chemical techniques based mainly on spectroscopic, calorimetric, hydrodynamic, etc., measurements. The major advantage of the physico-chemical methods is that they do not require large quantities of material and, if performed carefully, do not perturb examined reactions. Applications of several different physico-chemical approaches, commonly encountered in analyses of biochemical interactions, are here reviewed and discussed, using examples of simple binding reactions. It is stressed that without determination of the relationship between the measured signal and the total average degree of binding, the performed analysis of a single physico-chemical titration curve may provide only fitting parameters, instead of meaningful interaction parameters, already for the binding systems with only two ligand molecules. Some possible pitfalls in the analyses of single titration curves are discussed.

[The evaluation of unsaturation of blood lipids using methods of physical chemistry and clinical biochemistry. The insulin regulation of metabolism of fatty acids, number of double binds and cell absorption of glucose].

It is supposed that the main cause of insulin synthesis at late stages of phylogenesis became discrepancy between increase in vivo need in energy and physical chemical parameters of palmitic saturated fatty acid; its transportation to cells in composition of lipoproteins in optimal quantity (more than 15% of all fatty acids) became in vivo unfeasible. The biological role of insulin consists in supporting of insulin-dependent cells (skeletal miocytes in the first place) with substrates for gaining energy. The hormone transforms all palmitic saturated fatty acid endogenously synthesized from glucose into specific for animal cells rn-9 C18:1 oleic mono unsaturated fatty acid. The endogenous mono unsaturated fatty acid is oxidized by mitohondria with the highest constant of reaction velocity gaining for cells optimal quantity of biotransforming energy in the form of ATP. The insulin expresses in hepatocytes synthesis of oleic triglycerides and formation of oleic lipoproteins of very low density that only insulin-dependent cells absorb using apoE/B-100-endocytosis. The insulin expresses synthesis of Palmitoyl-KoA-elongase, stearyl-KoA-desaturase and glucose transporters 4, activates glucose absorption by cells with the purpose of synthesis endogenous oleic saturated fatty acid. The insulin substitutes in vivo ineffective palmitic alternative of metabolism of fatty acids for potentially more effective oleic metabolism of fatty acids. The insulin increases unsaturation of fatty acids and number of double binds in them. This can be established by direct titration of double binds by ozone on the basis of quantitative detection of fatty acids using technique of gas chromatography and calculating ratio C16:1/C16:0, C18:1/C18:0 and C18:1/C16:0. The diabetes mellitus is a disorder of metabolism of mono unsaturated fatty acid in the first place and only in the second place pathology of glucose absorption by cells.

Organic salts and aromatic substrates in two-component gel phase formation: the study of properties and release processes.

To identify gel phases able to act as confined reaction media or materials for the removal of organic pollutants, we studied two-component gel phases formed by naphthalenedisulfonate diimidazolium salts in the presence of some organic guests, in 1-propanol solution. Guests differing in π-surface area, bulkiness and electronic properties were taken into account. Soft materials obtained were investigated for their thermal stability, self-repairing ability and morphology. Furthermore, two-component gel phase formation was studied using resonance light scattering (RLS) measurements. Guest release processes from the gel phase were also studied. These processes were monitored as a function of time using both UV-vis and RLS measurements and considering important parameters such as the gelator concentration, the nature of extraction solvent and the extension of contact surface area between solvent and gel phase. Data collected shed light on the properties of the two-component gels and could represent a useful tool to better plan the application of these soft materials.