Morphological and Structural Evolutions of Metal–Organic Framework Particles from Amorphous Spheres to Crystalline Hexagonal Rods

Compositions as well as morphologies and structures of particles are vital factors that define their properties and applications. However, the morphology and structure changes associated with the composition change of metal–organic frameworks (MOFs) are barely studied. Herein, we report the morphology and structure changes of MOF particles associated with the ratio of two organic linkers incorporated within MOF particles, when they are constructed from the reactions of In(NO₃)₃ in the presence of isophthalic acid (H₂IPA) and/or 1,4‐benzenedicarboxylic acid (H₂BDC). Two tendencies—the tendency of BDC and In³⁺ to form porous crystalline hexagonal rods, and the tendency of IPA and In³⁺ to form non‐porous amorphous spherical particles—compete during the formation of MOF particles. Eventually, the incorporated ratio of BDC and IPA within the MOF particles, and thus their morphology and porosity, are controlled by altering the relative amounts of H₂BDC and H₂IPA used during the reactions.     

PTP1B Inhibitory Secondary Metabolites from an Antarctic Fungal Strain Acremonium sp. SF-7394

Chemical investigation of the Antarctic lichen-derived fungal strain Acremonium sp. SF-7394 yielded a new amphilectane-type diterpene, acrepseudoterin (1), and a new acorane-type sesquiterpene glycoside, isocordycepoloside A (2). In addition, three known fungal metabolites, (−)-ternatin (3), [D-Leu]-ternatin (4), and pseurotin A (5), were isolated from the EtOAc extract of the fungal strain. Their structures were mainly elucidated by analyzing their NMR and MS data. The absolute configuration of 1 was proposed by electronic circular dichroism calculations, and the absolute configuration of the sugar unit in 2 was determined by a chemical method. The inhibitory effects of the isolated compounds on protein tyrosine phosphatase 1B (PTP1B) were evaluated by enzymatic assays; results indicated that acrepseudoterin (1) and [D-Leu]-ternatin (4) dose-dependently inhibited the enzyme activity with IC₅₀ values of 22.8 ± 1.1 μM and 14.8 ± 0.3 μM, respectively. Moreover, compound 1 was identified as a competitive inhibitor of PTP1B.     

Plasmonic Octahedral Gold Nanoparticles of Maximized Near Electromagnetic Fields for Enhancing Catalytic Hole Transfer in Solar Water Splitting

Due to their localized surface plasmon resonances in visible spectrum, noble metal nanostructures have been considered for improving the photoactivity of wide bandgap semiconductors. Improved photoactivity is attributed to localized surface plasmon relaxations such as direct electron injection and resonant energy transfer. However, the details on the plasmonic solar water splitting through near electromagnetic field enhancement have not been fully understood. Here, the authors report that shape‐controlled gold nanoparticles on wide bandgap semiconductors improve the water‐splitting photoactivity of the semiconductors with over‐bandgap photon energies compared to sub‐bandgap photon energies. It is revealed that hot hole injection into the oxygen evolution reaction potential is the rate‐limiting step in plasmonic solar water splitting. The proposed concept of photooxidation catalysts derived from an ensemble of gold nanoparticles having sharp vertices is applicable to various photocatalytic semiconductors and provides a theoretical framework to explore new efficient plasmonic photoelectrodes.     

Novel polypyromellitimides and their liquid crystal aligning properties

Various aromatic poly{3,6‐bis[(4‐n‐alkyloxy)phenyloxy]‐pyromellitimide}s [poly(Ar‐C_m‐PMDA)s, m = 1, 4, 8, 12] were prepared in film form by routine two‐step condensation of 3,6‐bis[(4‐n‐alkyloxy)phenyloxy]pyromellitic dianhydrides (C_m‐PMDAs) with various aromatic diamines. After characterization of their chemical structures their solution, thermal and liquid crystal (LC)‐aligning properties in terms of pretilt angle at various rubbing densities were measured and discussed with respect to their backbone structures. All polyimide films showed excellent thermal stability and homogeneous LC alignment, but the poly(p‐phenylene‐C₁₂‐PMDA) exhibited completely homeotropic alignment while the pretilt angle values of poly(p‐phenylene‐C₈‐PMDA) varied with varying rubbing density.     

Comparable electrocatalytic performances of carbon- and Rh-loaded SrTiO3 nanoparticles

Both metallic Rh and nonmetallic carbon modifications can highly improve the electrocatalytic activity of SrTiO₃ nanoparticles. Carbon modifications was achieved by aerobic and anaerobic ethanol oxidation methods.     

Autonomic control of energy balance and glucose homeostasis

Neurons in the central nervous system (CNS) communicate with peripheral organs largely via the autonomic nervous system (ANS). Through such communications, the sympathetic and parasympathetic efferent divisions of the ANS may affect thermogenesis and blood glucose levels. In contrast, peripheral organs send feedback to the CNS via hormones and autonomic afferent nerves. These humoral and neural feedbacks, as well as neural commands from higher brain centers directly or indirectly shape the metabolic function of autonomic neurons. Notably, recent developments in mouse genetics have enabled more detailed studies of ANS neurons and circuits, which have helped elucidate autonomic control of metabolism. Here, we will summarize the functional organization of the ANS and discuss recent updates on the roles of neural and humoral factors in the regulation of energy balance and glucose homeostasis by the ANS.Subject terms: Autonomic nervous system, Homeostasis     

KFeO2 with corner-shared FeO4 frameworks as a new type of cathode material in potassium-ion batteries

Journal of Solid State Electrochemistry - KFeO2 is presented as a new type of cathode material for potassium-ion batteries. In contrast to LiFeO2 and NaFeO2, KFeO2 has tetrahedrally coordinated...