Simple to Quadruple Perovskite Transformation by Coordination Switching upon Solid-State Ion Exchange of NaNbO3.

Topotactic ion exchange is ubiquitous in the preparation of many metastable solids with layered structures. In recent times, the scope of chimie-douce ion exchange has been extended to quasi-2D and -3D structures including nanocrystals. The low-temperature solid-state exchange is yet another unique synthetic tool to access preconceived structures for the rational design of solids. Although rational synthesis using inorganic synthons is rare, few examples exist among inorganic solids with layered structures. Herein, we extend the scope further by transforming a simple perovskite (ABO3) into a high-pressure quadruple (AA'3B4O12) perovskite. The transformation is achieved at moderate temperatures and ambient pressure via a solid-state metathesis reaction, wherein the transition metal adopts a new A-cation coordination upon exchange. Such coordination switching upon ion exchange will open up possibilities for functionality-driven structural transformations and the rational design of new solids.

The role of reducibility vis-à-vis oxygen vacancies of doped Co3O4/CeO2 in the oxygen evolution reaction.

Electrochemical water splitting, which is a highly promising and environmentally friendly technology for H2 fuel production, faces significant hurdles due to the sluggish kinetics of the oxygen evolution reaction. Co -based oxides have garnered significant attention as alternative catalysts for the oxygen evolution reaction owing to the Co2+/Co3+ redox couple. Enhancing the challenging Co2+ → Co3+ oxidation process can further improve the catalytic oxygen evolution reaction. The aim of our work was to design a Co3O4-based catalyst to enhance reactivity by increasing the number of Co3+ active sites, serving as an excellent platform for facilitating the oxygen evolution reaction. To drive the effectiveness of the catalyst, in this study, we synthesized Co3O4 anchored on CeO2 (Co3O4/CeO2). The kinetics and efficacy of the oxygen evolution reaction catalysed by Co3O4/CeO2 was significantly improved by aliovalent doping of Sr into Ce sites and Cu into Co sites. The reducible nature of Ce stimulates the formation of Co3+ ions, resulting in an increased production of intermediate -OOH species, thus expediting the reaction. The transformation of Co2+ to Co3+ consequently leads to an increase in anion vacancies, which, in turn, promotes the adsorption of more intermediate species at the active site. The Sr- and Cu-doped Co3O4/CeO2 catalyst exhibited a high current density of 200 mA cm-2 at 580 mV and a low overpotential of 297 mV at 10 mA cm-2. The study functions as a key indicator to establish a connection between oxygen vacancies and metal oxidation states in order to investigate the mechanistic aspects of the oxygen evolution reaction on mixed metal oxides. Moreover, this study is expected to pave the way for the development of innovative oxygen evolution reaction catalysts with reducible supports, thus offering a new pathway for their design.

Medication adherence and quality of life among type-2 diabetes mellitus patients in India.

BACKGROUND: Diabetes mellitus (DM) is a progressively increasing metabolic disorder and a significant public health burden that demands immediate global attention. However, there is a paucity of data about adherence to antidiabetic drugs among patients with type-2 (T2)DM in Uttarakhand, India. Outpatient research reported that more than 50% of patients do not adhere to the correct administration and appropriate medicine dosage. It has been reported that patients with chronic diseases who adhere to treatment may experience improvement in quality of life (QoL) and vice versa. AIM: To assess the adherence to antidiabetic medication and QoL among patients with T2DM. METHODS: This cross-sectional descriptive study was conducted at a tertiary care hospital in Uttarakhand, India. The Medication Adherence Rating Scale and World Health Organization QoL-BREF scale were used to assess medication adherence and QoL. RESULTS: Two hundred seventy-seven patients suffering from T2DM participated in the study. Their mean age was 50.80 (± 10.6) years, 155 (56%) had a poor adherence level and 122 (44%) had a good adherence level to antidiabetic medications. After adjusting for sociodemographic factors, multiple linear regression analysis found patients who were adherent to antidiabetic medications had significantly higher mean overall perception of QoL and overall perception of health, with beta scores of 0.36 and 0.34, respectively (both P = 0.000) points compared with nonadherent patients. CONCLUSION: There was an association between medication adherence and QoL in patients with T2DM. Hence, there is a need to plan awareness and counseling programs followed by regular follow-up to motivate patient adherence to recommended treatment and lifestyle regimens.

A fasciclin-domain containing gene, ZeFLA11, is expressed exclusively in xylem elements that have reticulate wall thickenings in the stem vascular system of Zinnia elegans cv Envy.

The vascular cylinder of the mature stem of Zinnia elegans cv Envy contains two anatomically distinct sets of vascular bundles, stem bundles and leaf-trace bundles. We isolated a full-length cDNA of ZeFLA11, a fasciclin-domain-containing gene, from a zinnia cDNA library derived from in vitro cultures of mesophyll cells induced to form tracheary elements. Using RNA in situ hybridization, we show that ZeFLA11 is expressed in the differentiating xylem vessels with reticulate type wall thickenings and adjacent parenchyma cells of zinnia stem bundles, but not in the leaf-trace bundles that deposit spiral thickenings. Our results suggest a function for this cell-surface GPI-anchored glycoprotein in secondary wall deposition during differentiation of metaxylem tissue with reticulate vessels.

A RING domain gene is expressed in different cell types of leaf trace, stem, and juvenile bundles in the stem vascular system of zinnia.

The in vitro zinnia (Zinnia elegans) mesophyll cell system, in which leaf mesophyll cells are induced to transdifferentiate into tracheary elements with high synchrony, has become an established model for studying xylogenesis. The architecture of the stem vascular system of zinnia cv Envy contains three anatomically distinct vascular bundles at different stages of development. Juvenile vascular strands of the subapical region develop into mature vascular strands with leaf trace segments and stem segments. Characteristic patterns of gene expression in juvenile, leaf trace, and stem bundles are revealed by a molecular marker, a RING domain-encoding gene, ZeRH2.1, originally isolated from a zinnia cDNA library derived from differentiating in vitro cultures. Using RNA in situ hybridization, we show that ZeRH2.1 is expressed preferentially in two specific cell types in mature zinnia stems. In leaf trace bundles, ZeRH2.1 transcript is abundant in xylem parenchyma cells, while in stem bundles it is abundant in phloem companion cells. Both of these cell types show wall ingrowths characteristic of transfer cells. In addition, ZeRH2.1 transcript is abundant in some phloem cells of juvenile bundles and in leaf palisade parenchyma. The complex and developmentally regulated expression pattern of ZeRH2.1 reveals heterogeneity in the vascular anatomy of the zinnia stem. We discuss a potential function for this gene in intercellular transport processes.

Interallelic complementation at the Arabidopsis CRE1 locus uncovers independent pathways for the proliferation of vascular initials and canonical cytokinin signalling.

The differentiation of vascular tissue plays a central role in root architecture and its functionality. Regardless of its importance, the molecular mechanisms involved in the inception of vascular morphogenesis and their interaction with hormones are only now beginning to be understood. The characterisation of the WOODEN LEG (wol/cre1 mutant), impaired in procambial cell proliferation and the identification of WOL/CRE1 as a cytokinin receptor, provided the first genetic evidence pointing to a role of cytokinins in the formation of vascular initials. However, the striking wol phenotype in vascular differentiation is unique among all the available cre1 alleles collection. In this work, we identified a mutant with identical deficiencies in vascular differentiation as wol. Complementation analysis revealed that this mutant rescued the wol short-root phenotype. However, genetic characterisation of the mutant showed that the mutation was located at the CRE1 locus, indicating that both alleles displayed interallelic complementation. Trans-heterozygotes characterisation showed that these plants fully restored the deficiency in vascular differentiation but not the canonical cytokinin signalling. Furthermore, we show that, as measured in root growth inhibition, calli regeneration assays and northern analysis, the original wol allele is in fact more sensitive to cytokinins than the trans-heterozygous plants, or some cre1 alleles showing wild-type vascular morphogenesis. Thus, there is no strict correlation between the phenotype in vascular differentiation displayed by the cre1/wol alleles and canonical cytokinin signalling. These results indicate that at least partially independent regulatory circuits may operate in procambial cell proliferation and in cytokinin responsiveness exerted through the CRE1 receptor.

Role of death in providing lifeline to plants.

As the major transporters and distributors of water and minerals, xylem vessels and tracheids are the lifeline of plants. Interestingly, the building blocks of these water pipes are dead tracheary elements and vessel elements that have the process of cell death integrated into their differentiation programme. Using the Zinnia in vitro model system for xylogenesis, a key nuclease that is responsible for nuclear degradation during the terminal stages of tracheary element differentiation has been identified recently.