Search

ABSTRACT Aristoyunnolins G ( 1) and H ( 2), two new diastereoisomeric sesquiterpenes featuring a rare aristophyllene skeleton, were isolated from the traditional Chinese medicine Aristolochia yunnanensis. Their absolute stereochemistry involving three chiral centers was determined by combined chemical, spectral, and Density Functional Theory (DFT) calculation methods. Chirality 26:189-193, 2014. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The organomercury dimer [Hg2(PMP)Cl2]2 ·DMF ( 1) (PMP = 1-phenyl-3-methyl-2-pyrazolin-5-one) was prepared by the reaction of mercury chloride with PMP and characterized by elemental analysis, IR spectroscopy, TG, and single-crystal X-ray diffraction analysis. The title compound crystallizes in the triclinic space group P $\bar{1}$, with a = 7.4298(6), b = 9.0313(8), c = 12.4145(13) Å, V = 760.50(12) Å3, Z = 1. Each mercury(II) atom is tricoordinated to one chlorine atom, one carbon atom of the pyrazole ring from one PMP, and one oxygen atom from another PMP. The coordination arrangement around the mercury atom is T-shaped. This is the first structural report on an organomercury derivative of PMP. The distance between the two HgII ions is 3.2735(8) Å, which indicates the presence of weak Hg ···Hg interactions. Meanwhile, 1 can be connected by intermolecular C-H ···Cl hydrogen bonding and weak Hg ···O/Cl/N interactions to form a three dimensional network. The thermal stability and antibacterial activity of 1 were studied. The binding of 1 with calf thymus DNA was investigated by absorption spectroscopy and viscometry. [ABSTRACT FROM AUTHOR]

Sb2S3 is rapidly developed as light absorber material for solar cells due to its excellent photoelectric properties. However, the use of the organic hole transport layer of Spiro‐OMeTAD and gold (Au) in Sb2S3 solar cells imposes serious problems in stability and cost. In this work, low‐cost molybdenum (Mo) prepared by magnetron sputtering is demonstrated to serve as a back electrode in superstrate structured Sb2S3 solar cells for the first time. And a multifunctional layer of Se is inserted between Sb2S3/Mo interface by evaporation, which plays vital roles as: i) soft loading of high‐energy Mo particles with the help of cottonlike‐Se layer; ii) formation of surficial Sb2Se3 on Sb2S3 layer, and then reducing hole transportation barrier. To further alleviate the roll‐over effect, a pre‐selenide Mo target and consequentially form a MoSe2 is skillfully sputtered, which is expected to manipulate the band alignment and render an enhanced holes extraction. Impressively, the device with an optimized Mo electrode achieves an efficiency of 5.1%, which is one of the highest values among non‐noble metal electrode based Sb2S3 solar cells. This work sheds light on the potential development of low‐cost metal electrodes for superstrate Sb2S3 devices by carefully designing the back contact interface. [ABSTRACT FROM AUTHOR]

Multi‐wavelength quantum light sources are extremely desired in establishing communication links among multiple users for realizing quantum networks. Despite recent impressive advances, developing such a quantum light source with high quality remains challenging. Here a multi‐wavelength quantum light source using a silicon nitride micro‐ring with a free spectral range of 200 GHz is demonstrated. The generation of eight‐wavelength‐paired photon pairs is ensured in a wavelength range of 25.6 nm. With device optimization and noise‐rejecting filters, this source enables the generation of heralded single‐photons at a rate of 62 kHz with gh(2)(0)=0.014±0.001$g^{(2)}_{\text{h}}(0)=0.014\pm 0.001$ and the generation of energy‐time entangled photons with a visibility of 99.39±0.45%$99.39\pm 0.45\%$ in the Franson interferometer. These results, at room temperature and telecom wavelength, in a CMOS‐compatible platform, represent an important step toward integrated quantum photonic devices, which pave the way for realizing a large‐scale quantum network. [ABSTRACT FROM AUTHOR]

Heterotopic ossification (HO) is a common disturbing complication of intra‐articular fractures. Its prevention and treatment are still difficult as its pathogenesis is unclear. It was reported that PDGFRα+ muscle cells in skeletal muscle may participate in the formation of HO; however, the specific mechanism is still unknown. This study investigated the function of miR‐19b‐3p in osteogenic differentiation of PDGFRα+ muscle cells. MiR‐19b‐3p was upregulated during PDGFRα+ muscle cell osteogenic differentiation. The exogenous expression of miR‐19b‐3p led to an increase in osteogenic marker gene transcription and translation during the osteogenic differentiation of PDGFRα+ muscle cells. Furthermore, both alkaline phosphatase and alizarin red staining increased in miR‐19b‐3p mimic transfected cells. Over‐expression of miR‐19b‐3p led to the down‐regulation of gene of phosphate and tension homology deleted on chromosome ten (PTEN). Additionally, the dual luciferase reporter assay demonstrated that PTEN was a direct target of miR‐19b‐3p. The increase of osteocalcin, osteopontin, and Runt‐related transcription factor 2 protein levels induced by ectopic miR‐19b‐3p expression could be partially reversed by PTEN over‐expression. In conclusion, our results suggested that miR‐19b‐3p may be a promising target in inhibiting PDGFRα+ muscle cell osteogenic differentiation and treatment of HO. [ABSTRACT FROM AUTHOR]

Confronted with uncertainties, especially from large amounts of renewable energy sources, power flow studies need further analysis to cover the range of voltage magnitude and transferred power. To address this issue, this work proposes a novel interval power flow for the radial network by the use of an extended, simplified DistFlow formulation, which can be transformed into a set of interval linear equations. Furthermore, the Krawczyk iteration method, including an approximate inverse preconditioner using Frobenius norm minimisation, is employed to solve this problem. The approximate inverse preconditioner guarantees the convergence of the iterative method and has the potential for parallel implementation. In addition, to avoid generating a dense approximate inverse matrix in the preconditioning step, a dropping strategy is introduced to perform a sparse representation, which can significantly reduce the memory requirement and ease the matrix operation burden. The proposed methods are demonstrated on 33-bus, 69-bus, 123-bus, and several large systems. A comparison with interval LU decomposition, interval Gauss elimination method, and Monte Carlo simulation verifies its effectiveness. [ABSTRACT FROM AUTHOR]

ABSTRACT A July-May precipitation reconstruction for the period AD 1816-2010 was developed from a tree-ring width chronology of Picea wilsonii for the Xinglong Mountains area of Lanzhou. The reconstruction explains 55.8% of the actual precipitation variance during the calibration period from 1951 to 2010. Wet conditions prevailed during the periods 1822-1835, 1843-1858, 1870-1877, 1884-1891, 1911-1921, 1933-1938, 1944-1979 and 2009-2010. Dry episodes occurred during 1816-1821, 1836-1842, 1859-1869, 1878-1883, 1892-1910, 1922-1932, 1939-1943 and 1980-2008. Multi-taper method spectral analysis indicates the existence of some significant peaks at 2.8, 3.0 and 3.5 years. Spatial correlations with gridded land surface precipitation data revealed that our reconstruction represents regional precipitation signal for a large area of North China linked to the East Asian summer monsoon (EASM). Comparison with other tree-ring-based precipitation/drought reconstructions from surrounding areas implies a high degree of confidence for our reconstruction. Precipitation variations in the study area are significantly correlated with sea surface temperatures in eastern equatorial Pacific Ocean and tropical western Pacific Ocean, suggesting a possible connection of regional precipitation variations to the EASM and the El Niño-Southern Oscillation (ENSO). [ABSTRACT FROM AUTHOR]

The article presents a chemical formula related to the article "Caesalpinimin A, a Novel Rearranged Furanoditerpene with an Unprecedented Carbon Skeleton from the Seeds of Caesalpinia minax Hance" by J.-L. Zhang and others, published in the periodical "RSC Advances" in 2014.