Electrochemical Synthesis of Zirconium Pre-Catalysts for Homogeneous Ethylene Oligomerization

The catalytic activity of electrochemically synthesized zirconium carboxylates was studied in the process of ethylene oligomerization. Zirconium carboxylates were electrochemically synthesized directly from metallic zirconium and corresponding carboxylic acids (acetic, octanoic and lauric). A comprehensive study (element analysis, nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy, powder X-ray diffraction (PXRD)) of the synthesized zirconium carboxylates showed that these species contain bidentate carboxylate moieties. It was shown that obtained zirconium carboxylates, in combination with Et3Al2Cl3 (Al/Zr = 20), have a moderate activity of (7.6-9.9) × 103 molC2H4⋅molZr-1⋅h-1 in terms of ethylene oligomerization (at T = 80 ?C, p = 20 bar), leading to even-numbered C4-C10 linear alpha-olefins.1059-105

Investigation of Multilayer Nanostructures of Magnetic Straintronics Based on the Anisotropic Magnetoresistive Effect

The article presents the results of experimental studies of multilayer nanostructures of magnetic straintronics formed by magnetron sputtering on a 100 mm silicon wafer. The object of the study is two types of nanostructures: Ta/FeNiCo/CoFe/Ta and Ta/FeNi/CoFe/Ta, differing in the ratio of magnetic layers. The magnetic and magnetoresistive characteristics of multilayer nanostructures under varying mechanical loads are studied both on a 100 mm wafer and in the form of 4 × 20 mm2 samples of two types. The first, where the axis of easy magnetization is directed along the long side of the sample, and the second, where the axis of easy magnetization is a tilt at 45°. Based on the obtained data, the conclusions about the practical application of these nanostructures in magnetic straintronics elements are drawn

Red fluorescent redox-sensitive biosensor Grx1-roCherry

Redox-sensitive fluorescent proteins (roFPs) are a powerful tool for imaging intracellular redox changes. The structure of these proteins contains a pair of cysteines capable of forming a disulfide upon oxidation that affects the protein conformation and spectral characteristics. To date, a palette of such biosensors covers the spectral range from blue to red. However, most of the roFPs suffer from either poor brightness or high pH-dependency, or both. Moreover, there is no roRFP with the redox potential close to that of 2GSH/GSSG redox pair. In the present work, we describe Grx1-roCherry, the first red roFP with canonical FP topology and fluorescent excitation/emission spectra of typical RFP. Grx1-roCherry, with a midpoint redox potential of − 311 mV, is characterized by high brightness and increased pH stability (pKa 6.7). We successfully used Grx1-roCherry in combination with other biosensors in a multiparameter imaging mode to demonstrate redox changes in cells under various metabolic perturbations, including hypoxia/reoxygenation. In particular, using simultaneous expression of Grx1-roCherry and its green analog in various compartments of living cells, we demonstrated that local H2O2 production leads to compartment-specific and cell-type-specific changes in the 2GSH/GSSG ratio. Finally, we demonstrate the utility of Grx1-roCherry for in vivo redox imaging. Keywords: Grx1-roCherry, 2GSH/GSSG, Redox-sensitive fluorescent protein, Biosensor, Multiparameter imagin

Positive Effect of Cognitive Training in Older Adults with Different APOE Genotypes and COVID-19 History: A 1-Year Follow-Up Cohort Study

(1) Background: Older people suffer from cognitive decline; several risk factors contribute to greater cognitive decline. We used acquired (COVID-19 infection) and non-modifiable (presence of APOE rs429358 and rs7412 polymorphisms) factors to study the progression of subjective cognitive impairment while observing patients for one year. Cognitive training was used as a protective factor. (2) Methods: Two groups of subjects over the age of 65 participated in the study: group with subjective cognitive decline receiving cognitive training and individuals who did not complain of cognitive decline without receiving cognitive training (comparison group). On the first visit, the concentration of antibodies to COVID-19 and APOE genotype was measured. At the first and last point (1 year later) the Mini-Mental State Examination scale and the Hospital Anxiety and Depression Scale were performed. (3) Results: COVID-19 infection did not affect cognitive function. A significant role of cognitive training in improving cognitive functions was revealed. Older adults with APOE-ε4 genotype showed no positive effect of cognitive training. (4) Conclusions: Future research should focus on cognitive dysfunction after COVID-19 in long-term follow-up. Attention to the factors discussed in our article, but not limited to them, are useful for a personalized approach to maintaining the cognitive health of older adults

Hypocrates is a genetically encoded fluorescent biosensor for (pseudo)hypohalous acids and their derivatives.

The lack of tools to monitor the dynamics of (pseudo)hypohalous acids in live cells and tissues hinders a better understanding of inflammatory processes. Here we present a fluorescent genetically encoded biosensor, Hypocrates, for the visualization of (pseudo)hypohalous acids and their derivatives. Hypocrates consists of a circularly permuted yellow fluorescent protein integrated into the structure of the transcription repressor NemR from Escherichia coli. We show that Hypocrates is ratiometric, reversible, and responds to its analytes in the 10 Ms range. Solving the Hypocrates X-ray structure provided insights into its sensing mechanism, allowing determination of the spatial organization in this circularly permuted fluorescent protein-based redox probe. We exemplify its applicability by imaging hypohalous stress in bacteria phagocytosed by primary neutrophils. Finally, we demonstrate that Hypocrates can be utilized in combination with HyPerRed for the simultaneous visualization of (pseudo)hypohalous acids and hydrogen peroxide dynamics in a zebrafish tail fin injury model

Structure of human mitochondrial RNA polymerase elongation complex

Here we report the crystal structure of the human mitochondrial RNA polymerase (mtRNAP) transcription elongation complex, determined at 2.65-Å resolution. The structure reveals a 9-bp hybrid formed between the DNA template and the RNA transcript and one turn of DNA both upstream and downstream of the hybrid. Comparisons with the distantly related RNA polymerase (RNAP) from bacteriophage T7 indicates conserved mechanisms for substrate binding and nucleotide incorporation but also strong mechanistic differences. Whereas T7 RNAP refolds during the transition from initiation to elongation, mtRNAP adopts an intermediary conformation that is capable of elongation without refolding. The intercalating hairpin that melts DNA during T7 RNAP initiation separates RNA from DNA during mtRNAP elongation. Newly synthesized RNA exits toward the pentatricopeptide repeat (PPR) domain, a unique feature of mtRNAP with conserved RNA-recognition motifs