Interfacial reactions in lithia-based cathodes depending on the binder in the electrode and salt in the electrolyte

Lithia (Li2O)-based cathodes, utilizing oxygen redox reactions for obtaining capacity, exhibit higher capacity than commercial cathodes. However, they are highly reactive owing to superoxides formed during charging, and they enable more active parasitic (side) reactions at the cathode/electrolyte and cathode/binder interfaces than conventional cathodes. This causes deterioration of the electrochemical performance limiting commercialization. To address these issues, the binder and salt for electrolyte were replaced in this study to reduce the side reaction of the cells containing lithia-based cathodes. The commercially used polyvinylidene fluoride (PVDF) binder and LiPF6 salt in the electrolyte easily generate such reactions, and the subsequent reaction between PVDF and LiOH (from decomposition of lithia) causes slurry gelation and agglomeration of particles in the electrode. Moreover, the fluoride ions from PVDF promote side reactions, and LiPF6 salt forms POF3 and HF, which cause side reactions owing to hydrolysis in organic solvents containing water. However, the polyacrylonitrile (PAN) binder and LiTFSI salt decrease these side reactions owing to their high stability with lithia-based cathode. Further, thickness of the interfacial layer was reduced, resulting in decreased impedance value of cells containing lithia-based cathodes. Consequently, for the same lithia-based cathodes, available capacity and cyclic performance were increased owing to the effects of PAN binder and LiTFSI salt in the electrolyte.

Influence of protonation on the geometry of 2-{[(2,6-dimethylphenoxy)ethyl]amino}-1-phenylethan-1-ol: crystal structures of the free base and of its chloride and 3-hydroxybenzoate salt forms

The aroxyalkylaminoalcohol derivatives are a group of compounds known for their pharmacological action. The crystal structures of four new xylenoxyaminoalcohol derivatives having anticonvulsant activity are reported, namely, 2-{[2-(2,6-dimethylphenoxy)ethyl]amino}-1-phenylethan-1-ol, C18H23NO2, 1, the salt N-[2-(2,6-dimethylphenoxy)ethyl]-1-hydroxy-1-phenylethan-2-aminium 3-hydroxybenzoate, C18H24NO2 +·C7H5O3 −, 2, and two polymorphs of the salt (R)-N-[2-(2,6-dimethylphenoxy)ethyl]-1-hydroxy-1-phenylethan-2-aminium chloride, C18H24NO2 +·Cl−, 3 and 3p. Both polymorphs crystallize in the space group P21212 and each has two cations and two anions in the asymmetric unit (Z′ = 2). The molecules in the polymorphs show differences in their molecular conformations and intermolecular interactions. The crystal packing of neutral 1 is dominated by intermolecular O—H...N hydrogen bonds, resulting in the formation of one-dimensional chains. In the crystal structures of the salt forms (2, 3 and 3p), each protonated N atom is engaged in a charge-assisted hydrogen bond with the corresponding anion. The protonation of the N atom also influences the conformation of the molecular linker between the two aromatic rings and changes the orientation of the rings. The crystal packing of the salt forms is dominated by intermolecular O—H...O hydrogen bonds, resulting in the creation of chains and rings. Structural studies have been enriched by the calculation of Hirshfeld surfaces and the corresponding fingerprint plots.

Interfacial reactions in lithia-based cathodes depending on the binder in the electrode and salt in the electrolyte

Lithia (Li2O)-based cathodes, utilizing oxygen redox reactions for obtaining capacity, exhibit higher capacity than commercial cathodes. However, they are highly reactive owing to superoxides formed during charging, and they enable more active parasitic (side) reactions at the cathode/electrolyte and cathode/binder interfaces than conventional cathodes. This causes deterioration of the electrochemical performance limiting commercialization. To address these issues, the binder and salt for electrolyte were replaced in this study to reduce the side reaction of the cells containing lithia-based cathodes. The commercially used polyvinylidene fluoride (PVDF) binder and LiPF6 salt in the electrolyte easily generate such reactions, and the subsequent reaction between PVDF and LiOH (from decomposition of lithia) causes slurry gelation and agglomeration of particles in the electrode. Moreover, the fluoride ions from PVDF promote side reactions, and LiPF6 salt forms POF3 and HF, which cause side reactions owing to hydrolysis in organic solvents containing water. However, the polyacrylonitrile (PAN) binder and LiTFSI salt decrease these side reactions owing to their high stability with lithia-based cathode. Further, thickness of the interfacial layer was reduced, resulting in decreased impedance value of cells containing lithia-based cathodes. Consequently, for the same lithia-based cathodes, available capacity and cyclic performance were increased owing to the effects of PAN binder and LiTFSI salt in the electrolyte.

SYNTHESIS, ANTIAGGREGATION AND ANTITROMBOTIC ACTIVITIES OF NEW DERIVATIVES OF HYDROXYBENZOIC ACIDS WITH TAURIC FRAGMENT

A high prevalence of thrombotic disorders, insufficient effectiveness or safety of antithrombotic therapy is an urgent problem of modern healthcare. The main means of preventing thrombosis is acetylsalicylic acid. Despite its long history, aspirin attracts researchers in the fields of medicinal chemistry, biology, and medicine. The development of new antiplatelet agents, including chemical modification of the acetylsalicylic acid molecule, remains relevant. Modification of the acetylsalicylic acid molecule using amino acids and obtaining their salt forms makes it possible to maintain antiplatelet or antithrombotic properties, as well as to impart additional pharmacodynamic effects. In modern science, a lot of attention is paid to the sulfur-containing amino acid taurine. An analysis of modern scientific literature revealed the protective effect of taurine in diabetes mellitus and cardiovascular diseases, liver dysfunction, gastrointestinal tract, and kidney diseases.The aim of the article is to study synthesis of new compounds, determination of their physical characteristics and assessment of their antiplatelet and antithrombotic activities in vitro and in vivo.Materials and methods. To confirm the structure of the synthesized new derivatives of hydroxybenzoic acids with a taurine fragment by the acelation method, thin layer chromatography and NMR spectra were used. In vitro studies were carried out on the model of ADP-induced platelet aggregation according to the Born G. methods modified by V.A. Gabbasov. In vivo, the studies were carried out on the model of arterial thrombosis induced by the application of iron chloride in the following groups of animals: intact, with experimental diabetes mellitus and three-year-olds; the rate of bleeding from the tail vein was also evaluated.Results. New compounds – derivatives of ortho-, meta- and para-hydroxybenzoic acids with a taurine residue – were synthesized. A procedure for the preparation of N-hydroxybenzoyl taurine compounds and their salt forms have been described; their spectral characteristics and melting points have been determined. The synthesized compounds are superior to acetylsalicylic acid in solubility and are not inferior to it in antiplatelet and antithrombotic activities. The results of the in vitro antiplatelet activity assessment in a wide concentration range from 10-4M to 10-8M, are presented. It has been revealed that the dipotassium salt of N-(2-hydroxybenzoyl)taurine exhibits a less antiplatelet activity than the dipotassium salt of N-(3-hydroxybenzoyl)taurine. The most pronounced antiplatelet activity is exhibited by the compound N-(4-hydroxybenzoyl)taurine. In in vivo experiments on the model of arterial thrombosis in 3-year-olds or animals with experimental diabetes mellitus, carotid artery thrombosis occurred faster than in young or intact animals. A single preliminary oral administration of the test compounds prolonged the time of the thrombus formation, which makes it possible to conclude that they have an antithrombotic effect. In this study, the dipotassium salt of N-(3-hydroxybenzoyl)taurine exhibits a more pronounced activity than that of acetylsalicylic acid.Conclusion. Against the background of the modeled pathologies, the studied drugs showed the expected antithrombotic activity, in terms of the severity not inferior to that found in acetylsalicylic acid.

Dynamics of Eddies Generated by Sea Ice Leads

Interaction between the atmosphere and ocean in sea ice-covered regions is largely concentrated in leads, which are long, narrow openings between sea ice floes. Refreezing and brine rejection in these leads injects salt that plays a key role in maintaining the polar halocline. The injected salt forms dense plumes that subsequently become baroclinically unstable, producing submesoscale eddies that facilitate horizontal spreading of the salt anomalies. However, it remains unclear which properties of the stratification and leads most strongly influence the vertical and horizontal spreading of lead-input salt anomalies. In this study, the spread of lead-injected buoyancy anomalies by mixed layer and eddy processes are investigated using a suite of idealized numerical simulations. The simulations are complemented by dynamical theories that predict the plume convection depth, horizontal eddy transfer coefficient and eddy kinetic energy as functions of the ambient stratification and lead properties. It is shown that vertical penetration of buoyancy anomalies is accurately predicted by a mixed layer temperature and salinity budget until the onset of baroclinic instability (~3 days). Subsequently, these buoyancy anomalies are spread horizontally by eddies. The horizontal eddy diffusivity is accurately predicted by a mixing length scaling, with a velocity scale set by the potential energy released by the sinking salt plume and a length scale set by the deformation radius of the ambient stratification. These findings indicate that the intermittent opening of leads can efficiently populate the polar halocline with submesoscale coherent vortices with diameters of around 10 km, and provide a step toward parameterizing their effect on the horizontal redistribution of salinity anomalies.

Assessment of a Once-Daily Controlled-Release Ibuprofen Matrix Tablets Prepared Using Eudragit®E100/Carbopol®971P NF Polymers and Their Salts Combinations.

Introduction: Hydrophilic polymers that swell or dissolve in aqueous media can have the potential to prepare controlled/sustained dosage forms for weakly acidic, poorly soluble drugs. Objective: The main objective of this study is to utilize Eudragit®E100 (EE) and Carbopol®971P NF (Cp) polymers and their salt forms in the preparation of a once-daily controlled-release matrix tablet for model drug, Ibuprofen (IB). Methods: Combinations of the polymers in their base forms (EE)/(Cp) or their salt forms (EEHCl/CpNa) were compressed with (IB) into single layer matrix tablets, or otherwise into bilayer tablets. Dissolution profiles were constructed using three different consecutive stages (pH 1.2, 4.8, and 6.8). Result: It was found that the incorporation of (EEHCl) modified the release rates of (IB) from (Cp) based matrix tablets. However, a major enhancement of (IB) release rates occurred when the polymers were combined in their salt forms at a 1:1 ratio by weight. In addition, a bilayer tablet was prepared wherein a relatively rapidly disintegrating layer composed of polymers salts (EEHCl and CpNa), and a second layer containing only (Cp) polymer in its base form at a 1:2 weight ratio possessed excellent release properties, and mechanical strengths. Conclusion: It was concluded that the prepared bilayer tablet could be of promise use in controlling the release rates of (IB) in an extended manner to allow once-daily administration with an improved pH-independent release behavior.

TYPES OF CHITOZAN MODIFICATION BY USING VARIOUS DERIVATIVE AGENTS

The prevalence of the study of chitosan is associated with favorable biological properties of the polymer: low toxicity, biodegradability, and biocompatibility with cells of the human body. Chitosan is a complex aminopolysaccharide consisting of two types of monosaccharaides: 2-acetamide-D-glucose and 2-amino-D-glucose connected by a 1,4-β-glycosidic bond, obtained by chitosan by chitin deacetylation. Chitosan has hemostatic, hypolipedymic and antimicrobial activity against gram-positive and gram-negative microorganisms. However, the preparation of various drugs based on it is accompanied by difficulties in the development of biodegradable compositions that are related to the field of application. For the immobilization of various compounds used as drugs for the treatment of complications associated with damage to the skin, it is possible to use chitosan in dissolved form, converted into a salt form. However, salt forms of chitosan are water-soluble polymers, which leads to the rapid degradation of the matrix and the release of the drug from it, due to hydrophilicity. Additional lipophilization is required to obtain insoluble chitosan structures. Therefore, various modified chitosan structures are used that have suitable properties for the manufacture of a medicament. In addition, lipophilization of the chitosan structure allows the immobilization of more lipophilic structures. The purpose of this work was to study the literature and patent data sources for conducting information-analytical search of the approach. That led to the choice of a modified chitosan structure for its use in the pharmaceutical development of finished dosage forms. The article considers various types of derivatizing agents and the properties of modified chitosan structures.

Characterization of Different Salt Forms of Chitooligosaccharides and Their Effects on Nitric Oxide Secretion by Macrophages

In this paper, chitooligosaccharides in different salt forms, such as chitooligosaccharide lactate, citrate, adipate, etc., were prepared by the microwave method. They were characterized by SEM, FTIR, NMR, etc., and the nitric oxide (NO) expression was determined in RAW 264.7 cells. The results showed that pure chitooligosaccharide was an irregular spherical shape with rough surface, and its different salt type products are amorphous solid with different honeycomb sizes. In addition to the characteristic absorption peaks of chitooligosaccharides, in FTIR, the characteristic absorption of carboxyl group, methylene group, and aromatic group in corresponding acid appeared. The characteristic absorption peaks of carbon in carboxyl group, hydrogen and carbon in methyl, methylene group, and aromatic group in corresponding acid also appeared in NMR. Therefore, the sugar ring structure and linking mode of chitooligosaccharides did not change after salt formation of chitooligosaccharides. Different salt chitooligosaccharides are completely different in promoting NO secretion by macrophages, and pure chitooligosaccharides are the best.

Safety and Efficacy of Sodium and Potassium Arachidonic Acid Salts in the Young Pig

Arachidonic acid (ARA; 20:4n6) and docosahexaenoic acid (DHA; 22:6n3) are polyunsaturated fatty acids (FA) naturally present in breast milk and added to most North American infant formulas (IF). We investigated the safety and efficacy of novel sodium and potassium salts of arachidonic acid as bioequivalent to support tissue levels of ARA comparable to the parent oil; M. alpina oil (Na-ARA and K-ARA) and including a Na-DHA group. Pigs of both sexes were randomized to one of five dietary treatments (n = 16 per treatment; 8 male and 8 female) from postnatal day 2 to 23. ARA and DHA were included as either triglyceride (TG) or salt. Target dietary ARA/DHA concentrations as percent of total FA by weight were as follows: TT (0.47 TG/0.32 TG), NaT (0.47 Na-salt/0.32 TG), KT (0.47 K-salt/0.32 TG), and Na0 (0.47 Na-salt/0.00), NaNa (0.47 Na-salt/0.32 Na-salt). The primary outcome in this study was bioequivalence of ARA brain accretion. Growth performance; blood and tissue fatty acid levels; liver histology; complete blood cell counts; and serum chemistries were all evaluated. Overall, diets containing test sources of ARA and DHA did not affect growth performance; liver histology; or substantially influence hematological outcomes as compared with TT. The results confirm that the use of Na and K salt forms of ARA yield bioequivalent ARA accretion in the cerebral cortex and retinal tissue compared to TG-ARA. These findings confirm that use of Na-ARA and K-ARA salts in the young pig was safe and nutritionally bioequivalent to TG-ARA for critical neural tissues.