Proton spin-lattice relaxation study of the phase transition in TlH2AsO4

Measurements of the temperature and frequency dependence of the proton laboratory and dipolar frame spin-lattice relaxation rates in powdered TlH₂AsO₄ demonstrate that the ⁷⁵As quadrupole resonance frequency changes from v_Q ≈ 38 MHz at T ?T_c to v_Q 〈 10 MHz at T 〉 T_c. The structural phase transition at T_c = 251 K is thus connected with a disordering of the protons in the O–H … O bonds surrounding the AsO₄ groups.     

Supersymmetric σ-models,twistors, and the Atiyah-Hitchin metric

The Legendre transform and its generalizations, originally found in supersymmetric σ-models, are techniques that can be used to givelocal constructions of hyperkähler metrics. We give a twistor space interpretation to the generalizations of the Legendre transform construction. The Atiyah-Hitchin metric on the moduli space of two monopoles is used as a detailed example.     

Identification of protoberberine alkaloids as novel histone methyltransferase G9a inhibitors by structure-based virtual screening

The protein lysine methyltransferase G9a, which controls gene expression by epigenetic regulation of H3K9 methylation, is related to various human diseases, including cancer, drug addiction, and mental retardation. In recent years, genetic, biological, and physiological evidence has established G9a inhibitors as potential chemotherapeutic agents for cancer treatment. In this study, we identified protoberberine alkaloid pseudodehydrocorydaline (CT13) as a novel G9a inhibitor, by structure-based virtual screening of in-house library containing natural product compounds. The activity of CT13 was determined by biophysical analyses involving MALDI-TOF mass spectrometry and western blot analysis. CT13 showed selective inhibitory activity against G9a and suppressed the level of H3K9me2 in MCF7 human breast cancer cells. Molecular docking analysis suggested the binding mode of CT13 which occupies the binding site of histone H3 substrate. CT13 provides a novel scaffold for further development of analogous synthetic G9a inhibitors.

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Doppler spectroscopy of arbitrarily polarized light in rubidium

We present an experimental and theoretical study of the transmission of an arbitrarily polarized laser beam for a Doppler broadened rubidium vapor cell. As the polarization of the probe beam was varied from linear to circular, the transmission for the transitions F_g = 3 → F_e = 2, 3, 4 of the D₂ line of ⁸⁵Rb atoms was measured and compared with calculated results. In the calculation, the time-dependent absorption coefficient, calculated numerically from the density-matrix equation, was averaged over the velocity distribution and various transit time crossing the laser beam. The final transmission was obtained by considering the Gaussian profile of the laser beam. We found good agreement between experimental and calculated results.     

Honeycomb-like manganese oxide nanospheres for redox supercapacitors

Honeycomb-like MnO₂ nanospheres were synthesized using stainless steel substrates by a facile chemical bath deposition method. The obtained nanospheres were about 200–400 nm in diameter and consisted of porous ultrathin nanosheets. Honeycomb-like MnO₂ nanospheres exhibited a high specific capacitance of 240 F g^?1 and 87.1% capacitance retention after 1000 cycles at a current density of 0.5 A g^?1. These remarkable electrochemical results imply great potential for applications of the honeycomb-like MnO₂ nanospheres in supercapacitors.     

One-pot hydrothermal preparation of hierarchical manganese oxide nanorods for high-performance symmetric supercapacitors

An eco-friendly, new, and controllable approach for the preparation of manganese oxide(a-MnO₂) nanorods has been introduced using hydrothermal reaction for supercapacitor application. The in-depth crystal structure analysis of α-MnO₂ is analyzed by X-ray Rietveld refinement by using Full Prof program with the help of pseudo-Voigt profile function. The developed a-MnO₂ electrode attains a remarkable capacitance of 577.7 F/g recorded at a current density value of 1...