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The Hofmeister series characterizes the ability of salt anions to precipitate polyampholytes/proteins. However, the variation of protein size in the bulk solution of acids and the effect of salts on the same have not been studied well. In this article, the four acids (CH3COOH, HNO3, H2SO4, and HCl) and their effects on the hydrodynamic radius (RH) of gelatin in the bulk solution are investigated. The effects of Na salt with the same anions are also considered to draw a comparison between the interactions of acids and salts with polyampholytes. It is suggested that the interactions of polyampholytes with acids are different from those of salts. The interaction series of polyampholytes with acids with respect to the RH of the polyampholyte is C H 3 CO O − > N O 3 − > C l − > S O 4 2 − whereas the interaction series with salts is S O 4 2 − > C H 3 CO O − > C l − > N O 3 − . These different interactions are due to equilibration between acid dissociation and protonation of polyampholytes. Another important factor contributing to the interactions in weak acids is the fact that undissociated acid hinders the movement of dissociated acid. Experiments and simulations were performed to understand these interactions, and the results were identical in terms of the trend in RH (from the experiments) and the radius of gyration (Rg) (from the simulations). It is concluded that the valence of ions and dissociation affect the interaction in the case of acids. However, the interactions are influenced by the kosmotropic and chaotropic effect, hydration, and mobility in the case of salts. [ABSTRACT FROM AUTHOR]

The interactions of salts with polyampholytes are well established using the Hofmeister series. However, the effect of these salts on the diffusivities of polyampholytes is unknown. This article discusses these electrostatically driven physical interactions using two developed prediction models. Sodium and Potassium salts are considered with 3 chaotropic anions and 2 kosmotropic anions. A dimensionless parameter has been developed to predict the trend for these salt interactions. Another model has been developed to predict these interactions for different salt mixtures. The effect of these salts and the mixtures on the second virial coefficient is also studied, and statistical clustering using the k‐means method has been defined, which can provide insight towards the changes in the solution properties of polyampholytes with these salt mixtures. At lower pH, the salt first screens the repulsions in the polyampholytes followed by a re‐expansion phenomenon. [ABSTRACT FROM AUTHOR]

The depolymerization of lignin to produce renewable value-added building block chemicals has received increased attention from both industry and academia, as its facilitation is a key in the development of future biorefinery technologies. The main challenge in lignin depolymerization relies on its complex structure. Numerous efforts have shown that catalysts, solvents, reaction parameters, and physiochemical properties of lignin significantly affect the depolymerization reaction of lignin. Solvents are crucial components of the reaction system and affect the performance of the lignin depolymerization process. A good solvent can promote the solubility of lignin and enhance the catalyst–lignin interactions, and could also stabilize the reactive intermediates. However, the relationship and dependence of the molecular structure of lignins with its solubility and reactivity in different solvents are poorly understood. Thus, it is important to understand the influence of solvents on the reaction mechanism, the thermodynamic state of lignin, intermediates, products, and catalysts' stability. In this article, various solvents used in the depolymerization of different types of lignin reactions are extensively overviewed. Special attention is paid to comparing the conversion of lignin, yield of bio-oil, and yield of monomers in the presence of different polarity-categorized solvents and binary solvents. [ABSTRACT FROM AUTHOR]

Since coal washeries generate huge quantities of high-ash rejects as waste, effective utilization of coal rejects help in sustainable coal preparation. Out of different coal rejects, tailings from froth-flotation process can be a potential material for the extraction of clean coal due to its fine size, availability in the slurry form, presence of good carbon values, and better liberation properties. In the present study, three different methodologies i.e., chemical method, chemico-physical method, and physical method are explored to separate clean coal with >49.8% yield for their utilization in coke making process. The chemical method of demineralization by alkali-acid leaching shows a high clean coal yield of 65.4%; however, the alteration of vitrinite-group macerals makes it unsuitable for coke making process. Chemico-physical method of clean coal separation by hydrothermal extraction followed by density separation results in clean coal at 49.8% yield with an increase in vitrinite group macerals, which shows a positive impact on rheological and coking properties. The physical separation method by ultrafine grinding followed by density-gradient-centrifugation resulted in 58.2% of clean coal yield with coking properties similar to the clean coal obtained in conventional coal beneficiation plants. By adopting chemico-physical method and physical method of coal cleaning, the overall clean coal yield of the washery can be improved by >5.1%. Also, there is no deterioration in coke properties such as coke strength after reaction and coke reactivity index by using the prepared clean coal in coal blend. [ABSTRACT FROM AUTHOR]

Handling and disposal of high volume of fine coal tailings is a biggest challenge for coal washeries. Separation of clean coal by density separation and flotation shows limited yields of 23–28% and 13–14% respectively. Chemical leaching process has a challenge with the formation of insoluble salts. The present investigation aimed to separate clean coal by a combination of chemical-physical separation technique, i.e. alkaline hydrothermal process followed by density separation. Hydrothermal extraction of humic substance causes dissociation of coal aggregated structure (Mineral-Maceral-Pore structure), thus improves the separation. Experiments performed as per design of experiments and reduced design of experiments, where 100 µ particle size, 50% (w/w) pulp density, 4.5% KOH (w/w), and 140°C reaction temperature found to be optimum, at which 16.2% ash clean coal at 40.7% yield and humic acid by-product at 18.3% yield were obtained. Use of swelling agent such as tetrahydrofuran shown negative impact on clean coal recovery. Material balance and cost data were presented to show the techno-commercial viability of this technology. [ABSTRACT FROM AUTHOR]

Cellular hypoxia is a major cause of oxidative stress, culminating in neuronal damage in neurodegenerative diseases. Numerous ex vivo studies have implicated that hypoxia episodes leading to disruption of Ca2+ homeostasis and redox status contribute to the progression of various neuropathologies and cell death. Isolation and maintenance of primary cell culture being cost-intensive, the details of the time course relationship between Ca2+ overload, L-type Ca2+ channel function, and neurite retraction under chronic and long-term hypoxia remain undefined. In order to explore the effect of oxidative stress and Ca2+ overload on neurite length, first, we developed a 5-day-long neurite outgrowth model using N2a cell line. Second, we propose a chronic hypoxia model to investigate the modulation of the L-type Ca2+ channel (Cav1.2) and oxidative resistance gene (OXR1) expression level during the process of neurite retraction and neuronal damage over 32 h. Thirdly, we developed a framework for quantitative analysis of cytosolic Ca2+, superoxide formation, neurite length, and constriction formation in individual cells using live imaging that provides an understanding of molecular targets. Our findings suggest that an increase in cytosolic Ca2+ is a feature of an early phase of hypoxic stress. Further, we demonstrate that augmentation in the L-type channel leads to amplification in Ca2+ overload, ROS accumulation, and a reduction in neurite length during the late phase of hypoxic stress. Next, we demonstrated that non-prophylactic treatment of resveratrol leads to the reduction of calcium overloading under chronic hypoxia via lowering of L-type channel expression. Finally, we demonstrate that resveratrol-mediated reduction of Cav1.2 channel and STAT3 expression are associated with retention of neurite integrity. The proposed in vitro model assumes significance in the context of drug designing and testing that demands monitoring of neurite length and constriction formations by imaging before animal testing. [Display omitted] • Development of a cost-effective neurite outgrowth model for in vitro studies on neurite retraction. • AsSessment of neurite integrity and overall neuronal circuit through quantification of neurite length. • Non-prophylactic treatment of RSV leads to the reduction of Ca2+ overloading under hypoxia via lowering of Cav1.2 expression. • RSV mediated reduction of Cav1.2 and STAT3 expression is associated with retention of neurite integrity. [ABSTRACT FROM AUTHOR]