Hybrid exciton-polaritons in a bad microcavity containing the organic and inorganic quantum wells

We study the hybrid exciton-polaritons in a bad microcavity containing the organic and inorganic quantum wells. The corresponding polariton states are given. The analytical solution and the numerical result of the stationary spectrum for the cavity field are finishedComment: 3 pages, 1 figure. appear in Communications in Theoretical Physic

Distribution of Spectral Lags in Gamma Ray Bursts

Using the data acquired in the Time To Spill (TTS) mode for long gamma-ray bursts (GRBs) collected by the Burst and Transient Source Experiment on board the Compton Gamma Ray Observatory (BATSE/CGRO), we have carefully measured spectral lags in time between the low (25-55 keV) and high (110-320 keV) energy bands of individual pulses contained in 64 multi-peak GRBs. We find that the temporal lead by higher-energy gamma-ray photons (i.e., positive lags) is the norm in this selected sample set of long GRBs. While relatively few in number, some pulses of several long GRBs do show negative lags. This distribution of spectral lags in long GRBs is in contrast to that in short GRBs. This apparent difference poses challenges and constraints on the physical mechanism(s) of producing long and short GRBs. The relation between the pulse peak count rates and the spectral lags is also examined. Observationally, there seems to be no clear evidence for systematic spectral lag-luminosity connection for pulses within a given long GRB.Comment: 20 pages, 4 figure

Petroleum generation timing and source in the Northern Longmen Shan Thrust Belt, Southwest China: Implications for multiple oil generation episodes and sources

The temporal evolution of hydrocarbons (∼500 million bbl) and its relationship to the orogenic events of the Longmen Shan thrust belt have been extensively debated. The hydrocarbons occur as solid bitumen, as dykes and/or coatings within/along faults/fractures, and as present-day oil seeps. Here, utilizing organic geochemistry, we demonstrate that all of the bitumen exhibit similar organo-geochemical characteristics, and were sourced from the upper Neoproterozoic–lower Cambrian Doushantuo and Qiongzhusi Formations. In contrast, the organic geochemistry of the present-day oil seeps are distinct from that of the bitumen, and suggest that the source is the Permian Dalong Formation. Bitumen Re-Os data indicate that the upper Neoproterozoic–lower Cambrian Doushantuo and Qiongzhusi Formations underwent two temporally distinct oil-generation events; initial oil generation occurred during the Late Cambrian/Early Ordovician prior to the Caledonian orogeny, and secondly during the Jurassic (∼165 Ma) coinciding with the Indosinian-Yanshan orogenies. In contrast, the Re-Os data of the present-day oil seeps are too similar to yield a meaningful age, although the source is considered to have undergone hydrocarbon maturation between the Triassic and Jurassic. The temporal hydrocarbon evolution in the Longmen Shan thrust belt also provides an understanding of the hydrocarbon evolution and future exploration of the adjacent petroliferous Sichuan Basin

Enhancement in adsorption potential of microplastics in sewage sludge for metal pollutants after the wastewater treatment process

© 2019 Elsevier Ltd Microplastics (MPs) as new pollutants of environmental concern have been widely detected in sewage sludge, and may act as significant vectors for metal pollutants due to their adsorption property. Our findings show that Cd, Pb, and Co, but not Ni, contents in sewage sludge are lower than that of corresponding metal irons adsorbed on sludge-based MPs, indicating that the MPs accumulate such metal pollutants as Cd in the sludge samples. In contrast to virgin MPs, sludge-based MPs are one order of magnitude higher adsorption capacity for Cd, which reaches up to 2.523 mg g−1, implying that there is a considerable enhancement in adsorption potential of the MPs for metals after the wastewater treatment process. SEM analysis shows that sludge-based MPs have rougher and more porous surface than virgin MPs, and FTIR spectra reveal that functional groups such as C–O and O–H are found on sludge-based MPs. Further, two-dimensional FTIR correlation spectroscopy indicates that C–O and N–H functional groups play a vital role in the process that sludge-based MPs adsorb Cd, which are not found in virgin MPs. The results imply that increased adsorption potentials of the sludge-based MPs to Cd are attributed to changes in the MP physicochemical properties during wastewater treatment process. In addition, such factors as pH value, and sludge inorganic and organic components also have an effect on the MP adsorption to Cd. Principal component analysis shows that the MPs could be divided into three categories, i.e. polyamide, rubbery MPs (polyethylene and polypropylene) and glassy MPs (polyvinyl chloride and polystyrene). Their adsorption potentials to Cd follow the decreasing order: polyamide > rubbery MPs > glassy MPs. In summary, these findings indicate that MPs may exert an important influence on fate and transport of metal pollutants during sewage sludge treatment process, which deserves to be further concerned

Applying Neural Network based on Fuzzy Cluster Pre-processing to Thermal Error Modeling for Coordinate Boring Machine

AbstractTo investigate the effect of the thermal characteristics of a motorized spindle system on the precision of a machine tool, a thermal error model for spindle axial expansion and radial thermal declination is proposed. With precision CNC coordinate boring machine as an object, using the five-point method to calibrate spindle system thermal errors by the eddy current sensors for axial thermal elongation and radial thermal tilted values, and temperatures of measurement points are obtained by the PT100. The relationships between the rotational speed and temperature field, thermal errors are analyzed. Then fuzzy clustering analysis method is used to group and optimize the temperature variables, selecting the variables for thermal error-sensitive. Finally the MIMO artificial neural network approach is established for the spindle axial thermal elongation and radial thermal drifts. The results indicated that the model prediction accuracy could reach 86% with perfect generalization ability under different cutting conditions, providing a theoretical model and thermal characteristic parameters for both thermal error compensation and thermal equilibrium design

VEGF-siRNA silencing induces apoptosis, inhibits proliferation and suppresses vasculogenic mimicry in osteosarcoma in vitro

Aim: To inhibit the gene expression of vascular endothelial growth factor (VEGF) with the RNA interference (RNAi) technique and explore its influence on the apoptosis, proliferation, vasculogenic mimicry of osteosarcoma in vitro. Methods: PSilencer-VEGF plasmid transfected into osteosarcoma cell line of MG63 was recombinated by gene cloning, and VEGF expression was examined by Western blotting after transfection. The biological features of transfected MG63 including proliferation, apoptosis and vasculogenic mimicry, were assessed by MTT assay, flowcytometer, annexin V-FITC/PI, light microscopy and HE staining. Results: The sequence of pSilencer-VEGF plasmid was confirmed by DNA sequencing. Sequence-specific siRNA targeting VEGF significantly decreases its expression in MG63 cells. Cell growth was inhibited and early apoptosis was induced compared with non-siRNA tansfected cells. Decreased VEGF expression was associated with reduced vasculogenic mimicry of MG63 cells. Conclusions: VEGF gene might be closely related to the apoptosis and proliferation of osteosarcoma cells, and appears to be crucial for formation of vasculogenic mimicry in osteosarcoma. Inhibition of VEGF expression by sequence-specific siRNA may become a novel approach for the treatment of VEGF-enriched neoplasma such as osteosarcoma.Цель: ингибировать експрессию фактора роста эндотелия сосудов (VEGF) с помощью метода РНК интерференции (RNAi) и изучить влияние введения сайленсинга siRNA-VEGF на апоптоз, пролиферацию, васкулярную мимикрию клеток остеосаркомы in vitro. Методы: плазмида PSilencer-VEGF, рекомбинированная за счет клонирования специфической siRNA последовательности, была трансфецирована в клеточную линию остеосаркомы MG63. Экспрессию VEGF после трансфекции проверяли с помощью Вестерн-блот анализа. Биологические особенности трансфецированных клеток MG63, а именно пролиферацию, апоптоз и васкулярную мимикрию, изучали с помощью MTТ-анализа, проточной цитофлуориметрии, аннексина V-FITC/пропидиум йодида, световой микроскопии и окрашивания гематоксилином и эозином (HE). Результаты: последовательность, клонированная в плазмиду pSilencer-VEGF, проверена при секвенировании ДНК. Специфические к VEGF последовательности siRNA значительно снижали его экспрессию клетками MG63. В сравнении с клетками, трансфeцированными плазмидой без siRNA, рост клеток с PSilencer-VEGF был ингибирован, а также в них был индуцирован ранний апоптоз. Ингибирование экспрессии VEGF было ассоциировано со снижением васкулярной мимикрии клеток MG63. Выводы: ген VEGF может быть тесно связан с регуляцией апоптоза и пролиферации клеток остеосаркомы и может быть ключевым регулятором васкулярной мимикрии. Ингибирование экспрессии VEGF с помощью специфических siRNA можно рассматривать как новый подход к лечению опухолей, характеризующихся повышенной экспрессией VEGF, таких как остеосаркома