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  • Pickett Cox posted an update 6 days ago

    Such a structural transformation gives rise to the concomitant luminescent color change. The unique guest-induced fluorochromic phenomena, which are seldom reported in the previous host-guest systems, would be promising as tunable luminescent and ratiometric sensing materials.Molecular ferroelectrics are becoming an important area of research due to their ability to form a variety of structures exhibiting the desired properties. However, the precise control over the assembly of molecular building blocks for the design and synthesis of photoresponsive molecular ferroelectrics remains a considerable challenge. Here, we report a new hybrid high-temperature ferroelectric, (Me2NH2)[NaFe(CN)5(NO)], by judiciously assembling inorganic photochromic nitroprusside anion, as the framework building block, and polar organic cation Me2NH2+, as the dipole-moment carrier, into the crystal lattice. Ferroelectricity arises through the synergetic ordering of Me2NH2+ below 408 K. Piezoresponse force microscopy witnessed the presence of 180° ferroelectric domains and evidenced polarization switching by repeatedly applying an external electric field. Irradiation of the N-bound nitrosyl ligand (ground state) leads to two different conformations isonitrosyl O-bound (metastable state I) and side-on nitrosyl conformation (metastable state II). Such photoisomerization realized in solid-state molecular ferroelectrics allows for the photoswitching between the ferroelectric ground state and the metastable state. These results pave the way for new design approaches toward developing next-generation photostimulated ferroelectric materials at the molecular level.This paper, for the first time, provides evidence that current practices that lead to agricultural crop removal of potassium are unsustainable and likely contributed to the decline in dietary potassium intake and rise in hypokalemia prevalence in the US population. Potassium concentrations in beef, pork, turkey, fruit, vegetables, cereal crops, and so forth decreased between 1999 and 2015 based on the examination of potassium values of food items of USDA standard reference. Ratios of potassium input to removal by crops between 1987 and 2014, potassium in topsoil, and crop-available soil potassium in US farms all declined in recent years. Reported reductions in dietary potassium intake correspond to these decreases in the food supply and to increases in hypokalemia prevalence in the US population. Results of this paper provide new understanding on links between potassium management in agricultural practices and potassium intake deficits, which is needed for combating increasing hypokalemia prevalence in the US population.Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). Recently, ketogenic diet (KD) supplementation has attracted great interest. Therefore, we established the cuprizone (CPZ)-induced demyelination mouse model to investigate the possible neuroprotective effect of KD on the hippocampus of mice. We found that KD significantly elevated the level of serum β-hydroxybutyric acid, improved behavioral and motor abnormalities, and impaired the spatial learning and memory of CPZ-induced demyelination mice. Meanwhile, KD lessened the hippocampal demyelination by enhancing the expression of mature oligodendrocytes (OLs), which was revealed by the elevated expression of MBP and CNPase, as well as the luxol fast blue-staining intensity. Furthermore, KD inhibits the activation of microglia (especially M1-like microglia) and reactive astrocytes. Interestingly, KD attenuated the CPZ-induced oxidative stress by decreasing the malondialdehyde (MDA) content and restoring the glutathione (GSH) levels. In addition, the double immunofluorescence staining revealed that KD enhanced the expression of SIRT1 in astrocytes, microglia, and mature oligodendrocytes. Concomitantly, Western blot demonstrated that KD increased the expression of SIRT1, phosphorylated-AKT, mTOR, and PPAR-γ. In conclusion, KD exerted a neuroprotective effect on CPZ-induced demyelination mice, and this activity was associated with the modulation of the SIRT1/PPAR-γ and SIRT1/P-Akt/mTOR pathways.Oxygen evolution reaction (OER) with sluggish kinetics is the rate-determining step of water splitting, which dominates the solar-to-hydrogen fuel conversion efficiency. Herein, we constructed an oxygen vacancy-rich and highly reactive (222) facet in Co3O4 nanocrystals anchored on carbon nitride nanofiber (CNF) by a solvothermal reduction method. The resulting Co3O4 nanocrystals/CNF (COCNF) demonstrated a dramatically enhanced OER with a rate of 24.9 μmol/h under visible light, which is 124 times higher than that of CNF. This excellent catalytic activity of COCNF is based on a synergistic effect between its binary components for charge separation, oxygen vacancies for enhanced conductivity, and facet (222) exposure of Co3O4 nanocrystals for improved heterogeneous kinetics. Density functional theory (DFT) calculations revealed the water oxidation mechanism at different facets and found that the formed oxygen vacancies lead to a reduction of the materials’ bandgap. The correlation between Co3O4 crystal facets and the inherent OER catalytic activities under acidic solution was in the order of (222) > (220) > (311).A reinvestigation of the acetone extract of the strain CA-091830 of Streptomyces canus, producer of the imipenem potentiator krisynomycin, resulted in the isolation of two additional analogues, krisynomycins B (1) and C (2), with different chlorination patterns. check details Genome sequencing of the strain followed by detailed bioinformatics analysis led to the identification of the corresponding biosynthetic gene cluster (BGC) of this cyclic nonribosomal peptide family. The planar structure of the new molecules was determined using HRMS, ESI-qTOF-MS/MS, and 1D and 2D NMR data. Their absolute configuration was proposed using a combination of Marfey’s and bioinformatic BGC analyses. The krisynomycins displayed weak to negligible antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA), which was significantly enhanced when tested in combination with sublethal concentrations of imipenem. The halogenation pattern plays a key role in the antimicrobial activity and imipenem-potentiating effects of the compounds, with molecules having a higher number of chlorine atoms potentiating the effect of imipenem at lower doses.

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