Utilizing Nanostructured Materials for Hydrogen Generation, Storage, and Diverse Applications

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Utilizing Nanostructured Materials for Hydrogen Generation, Storage, and Diverse Applications

Recent progress in the nanoscale synthesis of metal-containing nanoscale materials, ultra-high surface area nanoporous materials and other functionalities has exbited a notable significant impact on the field of hydrogen storage, particularly in the realm of storing molecular hydrogen, where these nanomaterials provide increased binding sites on the large surface and in the pores, more extensive surface area and porosity as well depth of physisorption at elevated temperatures may significantly boost H2 storage capacity.


Abstract

The rapid advancement of refined nanostructures and nanotechnologies offers significant potential to boost research activities in hydrogen storage. Recent innovations in hydrogen storage have centered on nanostructured materials, highlighting their effectiveness in molecular hydrogen storage, chemical storage, and as nanoconfined hydride supports. Emphasizing the importance of exploring ultra-high-surface-area nanoporous materials and metals, we advocate for their mechanical stability, rigidity, and high hydride loading capacities to enhance hydrogen storage efficiency. Despite the evident benefits of nanostructured materials in hydrogen storage, we also address the existing challenges and future research directions in this domain. Recent progress in creating intricate nanostructures has had a notable positive impact on the field of hydrogen storage, particularly in the realm of storing molecular hydrogen, where these nanostructured materials are primarily utilized.

UPLC‐MS‐based metabolomics profiling and chemometric analysis for Hypericum sinaicum Boiss and the endophytic Aspergillus foetidus in comparison to Hypericum perforatum L.

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One of the endangered plant species in Saint Catherine protectorate is Hypericum sinaicum Boiss which is endemic to Egypt, Jordan, and Saudi Arabia. The fungus-host relationship can assist in the investigation of bioactive compounds produced by H. sinaicum paving the way for economic and medicinal implications. Therefore, a comprehensive metabolic approach via MS and chemical analysis was used to track and compare metabolites from H. sinaicum and Aspergillus foetidus var. pallidus, the endophytic fungus, with Hypericum perforatum. Metabolomics analysis revealed the presence of 25 metabolites distributed among samples and the discovery of new chemotaxonomic compounds, i.e., phloroglucinols and xanthones, allowing the discrimination between species. A. foetidus extract is considered a reliable source of furohyperforin and naphthodianthrone derivatives. In conclusion, using A. foetidus as an in vitro technique for producing potential phytoconstituents was cost effective, having easier optimization conditions and faster growth with fewer contamination rates than other in vitro methods.

Sulfoglycolipids and Related Analogues of Mycobacterium tuberculosis: Chemical Synthesis and Immunological Studies

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Mycobacterium tuberculosis (Mtb) causes tuberculosis as one major threat to human health, which has been deteriorated owing to the emerging multidrug resistance. Mtb contains a complex lipophilic cell wall structure that is important for bacterial persistence. Among the lipid components, sulfoglycolipids (SGLs), known to induce immune cell responses, are composed of a trehalose core attached with a conserved sulfate group and 1−4 fatty acyl chains in an asymmetric pattern. At least one of these acyl chains is polymethylated with 3−12 methyl branches. Although Mtb SGL can be isolated from bacterial culture, resulting SGL is still a homologous mixture, impeding accurate research studies. This up-to-date review covers the chemical synthesis and immunological studies of Mtb SGLs and structural analogues, with an emphasis on the development of new glycosylation methods and the asymmetric synthesis of polymethylated scaffolds. Both are critical to advance further research on biological functions of these complicated SGLs.

Peripheral insulin resistance is early, progressive, and correlated with cachexia in Walker‐256 tumor‐bearing rats

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Abstract

Insulin (INS) resistance is often found in cancer-bearing, but its correlation with cachexia development is not completely established. This study investigated the temporal sequence of the development of INS resistance and cachexia to establish the relationship between these factors in Walker-256 tumor-bearing rats (TB rats). INS hepatic sensitivity and INS resistance-inducing factors, such as free fatty acids (FFA) and tumor necrosis factor-α (TNF-α), were also evaluated. Studies were carried out on Days 2, 5, 8, and/or 12 after inoculation of tumor cells in rats. The peripheral INS sensitivity was assessed by the INS tolerance test and the INS hepatic sensitivity in in situ liver perfusion. TB rats with 5, 8, and 12 days of tumor, but not 2 days, showed decreased peripheral INS sensitivity (INS resistance), retroperitoneal fat, and body weight, compared to healthy rats, which were more pronounced on Day 12. Gastrocnemius muscle wasting was observed only on Day 12 of tumor. The peripheral INS resistance was significantly correlated (r = −.81) with weight loss. Liver INS sensitivity of TB rats with 2 and 5 days of tumor was unchanged, compared to healthy rats. TB rats with 12 days of tumor showed increased plasma FFA and increased TNF-α in retroperitoneal fat and liver, but not in the gastrocnemius, compared to healthy rats. In conclusion, peripheral INS resistance is early, starts along with fat and weight loss and before muscle wasting, progressive, and correlated with cachexia, suggesting that it may play an important role in the pathogenesis of the cachectic process in TB rats. Therefore, early correction of INS resistance may be a therapeutic approach to prevent and treat cancer cachexia.

The role of efferocytosis and transplant rejection: Strategies in promoting transplantation tolerance using apoptotic cell therapy and/or synthetic particles

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Abstract

Recently, efforts have been made to recognize the precise reason(s) for transplant failure and the process of rejection utilizing the molecular signature. Most transplant recipients do not appreciate the unknown length of survival of allogeneic grafts with the existing standard of care. Two noteworthy immunological pathways occur during allogeneic transplant rejection. A nonspecific innate immune response predominates in the early stages of the immune reaction, and allogeneic antigens initiate a donor-specific adaptive reaction. Though the adaptive response is the major cause of allograft rejection, earlier pro-inflammatory responses that are part of the innate immune response are also regarded as significant in graft loss. The onset of the innate and adaptive immune response causes chronic and acute transplant rejection. Currently employed immunosuppressive medications have shown little or no influence on chronic rejection and, as a result, on overall long-term transplant survival. Furthermore, long-term pharmaceutical immunosuppression is associated with side effects, toxicity, and an increased risk of developing diseases, both infectious and metabolic. As a result, there is a need for the development of innovative donor-specific immunosuppressive medications to regulate the allorecognition pathways that induce graft loss and to reduce the side effects of immunosuppression. Efferocytosis is an immunomodulatory mechanism with fast and efficient clearance of apoptotic cells (ACs). As such, AC therapy strategies have been suggested to limit transplant-related sequelae. Efferocytosis-based medicines/treatments can also decrease the use of immunosuppressive drugs and have no detrimental side effects. Thus, this review aims to investigate the impact of efferocytosis on transplant rejection/tolerance and identify approaches using AC clearance to increase transplant viability.

Early Organic Chemistry in Kyiv: Serhii Mykolayovych Reformatskyi (1860–1934) and his Name Reaction*

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Early Organic Chemistry in Kyiv: Serhii Mykolayovych Reformatskyi (1860–1934) and his Name Reaction*

Serhiy Mikolaevich Reformats'kiy (1867–1934) (Russian, Sergei Nikolaevich Reformatsky) was one of the founding fathers of organic chemistry in Ukraine. His eponymous reaction, between α-halozinc esters and aldehydes and ketones to give β-hyroxyesters, survived both the Grignard reaction and the modern crossed aldol addition, partly because of its success in synthesizing hindered compounds. His life and legacy are presented.


Abstract

Serhiy Mykolayovych Reformatskyi, [Ukrainian: Рeφopмaтcьκий, Cepгiй Mиκoлaйoвич; Russian: Sergei Nikolaevich Reformatskii, РeΦopмaтcκий, Cepгeй Hиκoлaeвич (1860-1934)] was a product of Zaitsev's laboratory in Kazan Imperial University in Russia and one of the founding fathers of organic chemistry in Ukraine. He discovered his eponymous reaction while a graduate student in Kazan under Zaitsev, studying the synthesis of homoallylic alcohols. He modified this reaction by replacing the olefinic π bond of an allyl halide with a carbonyl group. In the prototype reaction, he treated ethyl haloacetates with zinc and aldehydes or ketones. The reaction gave the corresponding β-hydroxyesters and remains an important synthetic method. Work on the reaction over the ensuing century and a quarter has led to the discovery of analogous reactions using a wide range of metals, and even permitting the use of water as a solvent.

Static field ionization of the spherically confined hydrogen atom

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Static field ionization of the spherically confined hydrogen atom

When a hydrogen atom is confined by a spherical potential well, its ionization due to a static electric field becomes a gradual and reversible phenomenon, that can be studied quantitatively with Quantum Monte Carlo methods.


Abstract

The ionization of the hydrogen atom confined in a spherical potential well and subjected to a static electric field is studied, using the diffusion Monte Carlo (DMC) method. Atomic ionization within a potential well is found to be a stationary, gradual, and reversible process. The value of the electric field at the onset of ionization is of the order of 0.1 atomic units, and depends on the symmetry of the atomic wave function and on the confinement dimension. By decreasing the confinement sphere, the difference between the bound and ionized states disappears, showing that strict confinement leads to pressure ionization of the atom. The off-center case is studied characterizing the potential energy surface (PES), and the transition between field-induced and pressure-induced ionization is confirmed. Except for very weak fields, the minimum of the PES is reached when the proton is in contact with the boundary of the well.