Computational Studies on the Ground State Tautomer,Hydrogen Conformations and Vibrational Spectroscopic Analysis of Antitumor Agents:3-Deazauracil and 6-Azauracil

The ground state hydrogen conformations and vibrational analysis of 3-deazauracil(3DAU)and 6-azauracil(6AU)tautomers(4-enol and 2,4-diol forms)have been calculated using ab initio Hartree-Fock(HF)and density functional theory(B3LYP)methods with 6-311++G(d,p)basis set level.The calculations have shown that the most probably preferential tautomer of 3DAU and 6AU are the 4-enol form,which gives best fit to the corresponding experimental data.The ground state conformer of the 2,4-diol form has two O—H bonds which are oriented externally and internally(to the N—H bond).The vibrational analyses of the ground state conformer of each tautomeric form of 3DAU and 6AU were done and their optimized geometry parameters(bond lengths and bond angles)were given.Furthermore,from the correlations values it was concluded that the B3LYP method is superior to the HF method for both the vibrational frequencies and the geometric parameters.

Directional mechanical and thermal properties of single-layer black phosphorus by classical molecular dynamics

Black phosphorus （BP） has received attention due to its own higher carrier mobility and layer dependent electronic properties, such as direct band gap. Interestingly, the single layer black phosphorus （SLBP） has had large popularity in applications related to thermoelectric, optoelectronic, and electronic devices. Here, we investigate the phonon spectrum, thermal conductivities, and stress strain effects. Robust anisotropy was mainly observed in the thermal conductivities together with the alongside zigzag （ZZ） direction value, compared to the armchair （AC） directions. We also investigated the attitude of stress that was anisotropic in both directions, and the stress effects were two times greater across the ZZ path than those in the AC direction at a low temperature. We obtained a ~oung＇s modulus of 63.77 and 20.74 GPa in the AC and ZZ directions, respectively, for a strain range of 0.01. These results had good agreement with first principle calculations. Our study here is useful and significant for the thermal tuning of phosphorus-based nanoelectronics and thermalelectric applications of phosphorus.

Low-temperature green synthesis of boron carbide using aloe vera

The unique structural and physical properties of boron carbide, which make it suitable for a wide range of applications,demands the development of low-cost and green synthesis method. In the present work, the commonly available leaves of aloe vera are hydrothermally treated to form the carbon precursor for the synthesis of boron carbide. The morphological characterization reveals the porous nature of the precursor turning into a tubular structure upon boron carbide formation.The structural characterization by x-ray diffraction and other spectroscopic techniques such as Fourier transform infrared,Raman, photoluminescence and uv-visible near-infrared spectroscopy confirm the formation of boron carbide. The thermogravimetric analysis of the sample is found to exhibit good thermal stability above 500 °C. When the sample is annealed to 600 °C, boron carbide with phase purity is obtained, which is confirmed through XRD and FTIR analyses. The optical emission properties of the sample are studied through CIE plot and power spectrum. Compared with other natural precursors for boron carbide, the aloe vera is found to give a good yield above 50%.

Organic-inorganic hybrid materials and architectures in optoelectronic devices: Recent advancements

Organic-inorganic hybrids are next-generation materials for use in high-performance optoelectronic devices owing to their adaptabilities in terms of design and properties.This article reviews the application of hybrid materials and layers in several widely used optoelectronic devices,i.e.,light amplification by stimulated emission of radiation(LASER),solar cells,and light-emitting diodes(LEDs).The effects of the incorporation of inorganic particles on photostability and optical gain are analyzed in the first section with reference to dye and perovskite lasers.Second,the strategies used in blending inorganic nanostructures into organic solar cells and bulk heterojunctions are analyzed.The use of various organic layers as electron-and hole-transport materials in Si heterojunction solar cells is reviewed in detail.Finally,the benefits of the presence of organic components in quantum-dot-and perovskite-based LEDs are derived from the analysis.The integration of organic and inorganic components with optimal interfaces and morphologies is a challenge in developing hybrid materials with improved efficiencies.

Carvacrol Promotes Cell Cycle Arrest and Apoptosis through PI3K/AKT Signaling Pathway in MCF-7 Breast Cancer Cells

Objective:To examine the role of carvacrol in modulating PI3 K/AKT signaling involved in human breast cancer pathogenesis using in vitro experimental model MCF-7 cells.Methods:MTT and lactate dehydrogenase assays were performed with cells treated with different doses of carvacrol(0–250μmol/L)at different time points(24 and 48 h).The nuclear morphology was assessed in MCF-7 cells with propidium iodide(PI)and acridine orange/ethidium bromide(AO/EB)staining and analyzed by fluorescence microscopy.Events like cell cycle arrest and apoptosis were observed by flow cytometric analysis and expressions of p-Rb,cyclin D1,cyclin-dependent kinase 4(CDK4),CDK6,Bax,Bcl-2,PI3 K/p-AKT were analyzed by immunoblot.Results:Carvacrol significantly reduced cell viability with the half maximal inhibitory concentration value of 200μmol/L at 24 and 48 h(P<0.05).importantly,there was a significant increase in the accumulation of the G0/G1 phase upon treatment with carvacrol in MCF-7 cells(P<0.05 or P<0.01).A remarkable decrease in protein expressions of p-Rb,cyclin D1,CDK4 and CDK6 denoted cell cycle arrest(P<0.05 or P<0.01).In addition,carvacrol treatment significantly inhibited PI3 K/p-AKT protein expressions leading to induction of apoptosis mediated by decreased Bcl2 and increased Bax protein expressions.Further,Annexin V/PI staining by FACS analysis,dual staining by AO/EB and PI staining studies suggested induction of apoptosis by carvacrol through PI3 K/Akt signaling pathway in MCF-7 cells.Conclusion:Carvacrol significantly inhibited the breast cancer MCF-7 cell proliferation and induced apoptosis via suppressing PI3/AKT signaling pathway.