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Inhibition of the molecular chaperone heat shock protein 90 (Hsp90) represents a promising approach for cancer treatment. BIIB021 is a highly potent Hsp90 inhibitor with remarkable anticancer activity, however, its clinical application is limited by lack of potency and response. In this study, we aimed to investigate the impact of replacing the hydrophobic moiety of BIIB021, 4-methoxy-3,5-dimethylpyridine, with various five-membered ring structures on the binding to Hsp90. A focused array of N7/N9-substituted purines, featuring aromatic and non-aromatic rings, was designed, considering the size of hydrophobic pocket B in Hsp90 to obtain insights into their binding modes within the ATP binding site of Hsp90 in terms of &pi, &ndash, &pi, stacking interactions in pocket B as well as outer &alpha, helix 4 configurations. The target molecules were synthesized and evaluated for their Hsp90&alpha, inhibitory activity in cell-free assays. Among the tested compounds, the isoxazole derivatives 6b and 6c, and the sole six-membered derivative 14 showed favorable Hsp90&alpha, inhibitory activity, with IC50 values of 1.76 &micro, M, 0.203 &micro, M, and 1.00 &micro, M, respectively. Furthermore, compound 14 elicited promising anticancer activity against MCF-7, SK-BR-3, and HCT116 cell lines. The X-ray structures of compounds 4b, 6b, 6c, 8, and 14 bound to the N-terminal domain of Hsp90 were determined in order to understand the obtained results and to acquire additional structural insights, which might enable further optimization of BIIB021.

Ru-based electrocatalysts are generally known to be suitable for the oxygen evolution reaction (OER), but they have intrinsic problems in balancing catalytic activity and stability. In this study, we took the strategy, introducing Pt atoms into the structure of crystalline RuO2 to enhance the catalytic property toward OER while maintaining durability. The OER activity of Ru0.9Pt0.1O2/C with high stability was significantly higher than that of RuO2/C. In situ/operando ICP-MS analysis showed that Ru dissolution of Ru0.9Pt0.1O2/C during OER was suppressed by introducing Pt and thermal treatment when compared to Ru/C. The XPS results after OER measurement indicated that the Ru oxidation state of Ru0.9Pt0.1O2/C was higher than that of RuO2, which led to high OER catalytic activity. Based on these results, we hypothesize that the enhanced OER activity of Ru0.9Pt0.1O2/C was due to the change in the reaction mechanism from “adsorbate evolution” to “lattice participation”. Our findings increase the possibility of significantly overcoming the activity and stability limits of Ru-based electrocatalysts for the OER using Pt. Keywords: Water splitting, Oxygen evolution reaction, Ruthenium‑platinum oxide, in situ/operando ICP-MS, Lattice participation mechanism

An extremely thin bilayer electrolyte consisting of yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC) is successfully fabricated on a sintered NiO-YSZ substrate. Major processing flaws are effectively eliminated by applying local constraints to YSZ nanoparticles, and excellent open circuit voltage and cell performance are demonstrated in a solid oxide fuel cell (SOFC) at intermediate operating temperatures.

Novel heterolayered nanocomposites consisting of interstratified MnO2 and [Mn1/3Co1/3Ni1/3]O-2 nanosheets are synthesized by a layer-by-layer self-assembly between negatively charged metal oxide nanosheets and lithium cations. According to powder X-ray diffraction and micro-Raman analysis, all of the as-prepared Li+-xMnO(2)-(1-x)[Mn1/3Co1/3Ni1/3]O-2 nanocomposites with x = 1, 0.7, and 0.4 have a lamella structure with similar basal spacing of similar to 7.1 angstrom, indicating the formation of lithium intercalation structure with cointercalated water bilayers. The nanoscale mixing of MnO2 and [Mn1/3Co1/3Ni1/3]O-2 nanosheets is confirmed by energy-dispersive spectrometry-elemental mapping analysis. Upon a self-assembly with Li+ ions, there occur no marked changes in the octahedral symmetry and mixed oxidation state of M3+/M4+ ions (M = Mn, Co, and Ni) in the precursor metal oxide nanosheets. All of the as-prepared nanocomposites commonly experience a structural transformation from hydrated layered structure to dehydrated layered structure at 200 degrees C, which is followed by the second-phase transition to cubic spinel structure at 600 degrees C. Despite distinct structural changes of the nanocomposites at elevated temperatures, their porous stacking structure is well-maintained up to 400 degrees C. The heat-treatment at 400 degrees C leads to a significant improvement of the discharge capacity of the present nanocomposites because of the dehydration of as-prepared materials and the enhancement of crystallinity. The doping of [Mn1/3Co1/3Ni1/3]O-2 layers enables us not only to increase the discharge capacity of the Li-MnO2 nanocomposite but also to prevent the phase transition of layered manganese oxide to spinel structure during electrochemical cycling. The present study clearly demonstrates that a postcalcination process as well as a partial doping of [Mn1/3Co1/3Ni1/3]O-2 layer is effective in improving the electrode performance of reassembled Li-MnO2 nanocomposites. Refereed/Peer-reviewed

Porously assembled 2D nanosheets of alkali metal manganese oxides were synthesized via the flocculation of exfoliated MnO2 nanosheets with alkali metal cations. According to X-ray diffraction and electron microscopic analyses, the MnO2 nanosheets were porously restacked with alkali metal cations, resulting in the mesoporous assembly of lamellar crystallites with surface expansion (similar to 50-70 m(2) g(-1)). Mn K-edge X-ray absorption spectroscopy clearly demonstrated that manganese ions in the reassembled materials were stabilized in octahedral symmetry with the mixed oxidation state of Mn3+/Mn4+. The present reassembled manganates showed large capacitances of similar to 140-160 F g(-1) and excellent cyclability of similar to 93-99% up to the 1000th cycle. The electrochemical cycling did not induce notable frustration in the crystal structure of manganate nanosheets, underscoring the high structural stability of the reassembled manganates. This study provided strong evidence for the effectiveness of the exfoliation-reassembling method in enhancing the capacitance performance of layered metal oxides. Refereed/Peer-reviewed

Homogeneously mixed colloidal suspensions of reduced graphene oxide, or RGO, and layered manganate nanosheets have been synthesized by a simple addition of the exfoliated colloid of RGO into that of layered MnO 2. The obtained mixed colloidal suspensions with the RGO/MnO 2 ratio of ≤0.3 show good colloidal stability without any phase separation and a negatively charged state with a zeta (ζ) potential of -30 to -40 mV. The flocculation of these mixed colloidal suspensions with lithium cations yields porous nanocomposites of Li/RGO-layered MnO 2 with high electrochemical activity and a markedly expanded surface area of around 70-100 m 2 g -1. Relative to the Li/RGO and Li/layered MnO 2 nanocomposites (≈116 and ≈167 F g -1), the obtained Li/RGO-layered MnO 2 nanocomposites deliver a larger capacitance of approximately 210 F g -1 with good cyclability of around 95-97 % up to the 1000th cycle, thus indicating the positive effect of hybridization on the electrode performances of RGO and lithium manganate. Also, an electrophoretic deposition of the mixed colloidal suspensions makes it possible to easily fabricate uniform hybrid films composed of graphene and manganese oxide. The obtained films show a distinct electrochemical activity and a homogeneous distribution of RGO and MnO 2. The present experimental findings clearly demonstrate that the utilization of the mixed colloidal suspensions as precursors provides a facile and universal methodology to synthesize various types of graphene/metal oxide hybrid materials. Refereed/Peer-reviewed

Nanocomposites of reduced graphene oxide and manganese (II,III) oxide can be synthesized by the freeze-drying process of the mixed colloidal suspension of graphene oxide and manganese oxide, and the subsequent heat-treatment. The calcined reduced graphene oxide-manganese (II,III) oxide nanocomposites are X-ray amorphous, suggesting the formation of homogeneous and disordered mixture without any phase separation. The reduction of graphene oxide to reduced graphene oxide upon the heat-treatment is evidenced by Fourier-transformed infrared spectroscopy. Field emission-scanning electronic microscopy and energy dispersive spectrometry clearly demonstrate the formation of porous structure by the house-of-cards type stacking of reduced graphene oxide nanosheets and the homogeneous distribution of manganese ions in the nanocomposites. According to Mn K-edge X-ray absorption spectroscopy, manganese ions in the calcined nanocomposites are stabilized in octahedral symmetry with mixed Mn oxidation state of Mn(II)/Mn(III). The present reduced graphene oxide-manganese oxide nanocomposites show characteristic pseudocapacitance behavior superior to the pristine manganese oxide, suggesting their applicability as electrode material for supercapacitors. Refereed/Peer-reviewed