Facies-controlled prediction of dolomite reservoirs in the Middle Permian Qixia Formation in Shuangyushi,northwestern Sichuan Basin

The Middle Permian Qixia Formation in the Shuangyushi area,northwestern Sichuan Basin,develops shoal-facies dolomite reservoirs.To pinpoint promising reservoirs in the Qixia Formation,deep thin shoal-facies dolomite reservoirs were predicted using the techniques of pre-stack Kirchhoff-Q compensation for absorption,inverse Q filtering,low-to high-frequency compensation,forward modeling,and facies-controlled seismic meme inversion.The results are obtained in six aspects.First,the dolomite reservoirs mainly exist in the middle and lower parts of the second member of Qixia Formation(Qi2 Member),which coincide with the zones shoal cores are developed.Second,the forward modeling shows that the trough energy at the top and bottom of shoal core increases with increasing shoal-core thickness,and weak peak reflections are associated in the middle of shoal core.Third,five types of seismic waveform are identified through waveform analysis of seismic facies.Type-Ⅰ and Type-Ⅱ waveforms correspond to promising facies(shoal core microfacies).Fourth,vertically,two packages of thin dolomite reservoirs turn up in the sedimentary cycle of intraplatform shoal in the Qi2 Member,and the lower package is superior to the upper package in dolomite thickness,scale and lateral connectivity.Fifth,in plane,significantly controlled by sedimentary facies,dolomite reservoirs laterally distribute with consistent thickness in shoal cores at topographical highs and extend toward the break.Sixth,the promising prospects are the zones with thick dolomite reservoirs and superimposition of horstegraben structural traps.

Tensile Mechanical Behavior and Failure Mechanism of a Plain-Woven SiCf/SiC Composites at Room and Elevated Temperatures

Ceramic matrix composites (CMCs) are the preferred materials for solving advanced aerospace high-temperature structural components;it has the comprehensive advantages of higher temperature (~1500˚C) and low density. In service environments, CMCs exhibit complex damage mechanisms and failure modes, which are affected by constituent materials, meso-architecture and inhere defects. In this paper, the in-plane tensile mechanical behavior of a plain-woven SiCf/SiC composite at room and elevated temperatures was investigated, and the factors affecting the tensile strength of the material were discussed in depth. The results show that the tensile modulus and strength of SiCf/SiC composites at high temperature are lower, but the fracture strain increases and the toughness of the composites is enhanced;the stitching holes significantly weaken the tensile strength of the material, resulting in the material is easy to break at the cross-section with stitching holes.

Physiological and transcriptome analyses of Chinese cabbage in response to drought stress

Chinese cabbage is an important leafy vegetable crop with high water demand and susceptibility to drought stress.To explore the molecular mechanisms underlying the response to drought,we performed a transcriptome analysis of drought-tolerant and-sensitive Chinese cabbage genotypes under drought stress,and uncovered core drought-responsive genes and key signaling pathways.A co-expression network was constructed by a weighted gene coexpression network analysis(WGCNA)and candidate hub genes involved in drought tolerance were identified.Furthermore,abscisic acid(ABA)biosynthesis and signaling pathways and their drought responses in Chinese cabbage leaves were systemically explored.We also found that drought treatment increased the antioxidant enzyme activities and glucosinolate contents significantly.These results substantially enhance our understanding of the molecular mechanisms underlying drought responses in Chinese cabbage.

间二甲苯的离解光电离的实验与理论研究

本文利用同步辐射真空紫外和超声分子束反射式飞行时间质谱系统研究间二甲苯的光电离和离解光电离.通过测定母体离子C_(8)H_(10)^(+)和主要碎片离子(C_(8)H_(9)^(+)和C_(7)H_(7)^(+))的光电离效率谱,确定了母体分子的电离能和主要碎片离子(C_(8)H_(8)^(+)和C_(7)H_(7)^(+))的出现势分别为8.60±0.03 eV,11.76±0.04 eV和11.85±0.05 eV eV.在B3LYP/6-311++G(d,p)水平上优化了两个主要解离通道的反应物、过渡态、中间体和产物的结构,并在G3水平上计算了它们的能量,以及两个主要的离解光电离通道产物C_(7)H_(7)^(+)+CH_(3)和C_(8)H_(9)^(+)+H的能量.结合理论和实验结果,间二甲苯的离解光电离机理主要过程是C-H键或C-C键的离解和氢迁移.

High-ductility fine-grained Mg-1.92Zn-0.34Y alloy fabricated by semisolid and then hot extrusion

The combination of semisolid and hot extrusion processing was applied to refine the icosahedral quasicrystalline phase(I-phase) in an extruded Mg-1.92Zn-0.34Y(wt.%) alloy for the first time. The semisolid isothermal heat treatment transformed the micron-sized I-phase particles into nano lamellar eutectic(α-Mg + I-phase) with a lamellar spacing of ?86 nm. After subsequent hot extrusion at 250 ℃, the nano lamellar eutectic phases were broken into uniformly dispersed nanoscale I-phase particles. What’s more, the matrix microstructure was significantly refined with an equiaxed average grain size of 2.59 ± 0.81 μm, and an unusual texture component(most of the grains’ c-axis is parallel to the extrusion direction) was observed. The processed alloy exhibited a high tensile elongation to failure(EL) of 44 ± 2.6%with an ultimate tensile strength(UTS) of 258 ± 2.0 MPa and a tensile yield strength(TYS) of 176 ± 1.6 MPa at room temperature.The high ductility from the combined effects of the grain refinement, dispersion of nanoscale I-phase particles, and the unusual texture.The uniform dispersion of nanoscale I-phase particles could promote grain refinement by particle stimulated nucleation mechanism, and thus bring the unusual texture(where the c-axis is aligned parallel to the extrusion direction during dynamic recrystallization, which contributed to ductility).

资本自由化、内部资本配置与代理成本

本文从外部制度环境和内部资本配置两个角度,对创业企业代理成本影响因素展开大样本实证研究.研究结果表明,区域的资本自由化程度越高,创业企业的代理成本越低,其中由降低政府干预程度和产权制度创新构成的资本自由化因素作用最为明显.研究还发现,创业企业的内部资本配置对代理成本有着重要影响,具体表现为:1)拥有个人资本或外商资本的创业企业代理成本显著低于拥有国家资本的创业企业,并且外商资本比例或个人资本比例越高,代理成本越低;2)短期负债率的提高能有效降低以营业费用率为表征的代理成本,但却提高了以管理费用率为代表的代理成本,显示现阶段我国债权人治理效应仍然存在一定的局限性.这部分结果在一定程度上也为资本自由化进程对创业企业治理影响机理提供了证据.本文的研究为未来金融改革方向、创业环境政策制定及国有创业企业产权多元化提供了一定的实证依据.

玻璃体腔注射康柏西普联合激光光凝治疗糖尿病性黄斑水肿的效果分析

目的:分析玻璃体腔注射康柏西普联合视网膜激光光凝治疗糖尿病性黄斑水肿(diabetic macular edema,DME)的临床疗效。方法:选取2015-06/2016-12我院确诊的DME患者73例80眼,根据治疗方式不同分为对照组和治疗组,对照组采用视网膜激光光凝治疗,治疗组采用玻璃体腔注射康柏西普联合激光光凝治疗。观察治疗前和治疗后3mo两组患者最佳矫正视力(BCVA)、视网膜厚度及并发症发生情况。结果:治疗后3mo,两组患者BCVA均较治疗前显著改善,且治疗组患者BCVA显著优于对照组;两组患者黄斑上方、下方、颞侧、鼻侧环状区的视网膜厚度和平均视网膜厚度均低于治疗前,且治疗组患者的平均视网膜厚度显著低于对照组,差异均有统计学意义(P<0.05)。随访期间,所有患者均未出现角膜水肿、前房炎性反应、视网膜出血、新生血管性青光眼、眼内炎等严重眼部并发症及全身不良反应。结论:与单纯视网膜激光治疗相比,玻璃体腔注射康柏西普联合视网膜激光光凝治疗DME在改善视力、恢复视网膜功能方面效果更佳,且具有良好的安全性。

Electrostatic-lenses position-sensitive TOF MCP detector for beam diagnostics and new scheme for mass measurements at HIAF

A foil–microchannel plate(MCP)detector,which uses electrostatic lenses and possesses both good position and timing resolutions,has been designed and simulated for beam diagnostics and mass measurements at the next-generation heavy-ion-beam facility HIAF in China.Characterized by low energy loss and good performances of timing and position measurements,it would be located at focal planes in fragment separator HFRS for position monitoring,beam turning,Bq measurement,and trajectory reconstruction.Moreover,it will benefit the building-up of a magnetic-rigidity–energy-loss–time-offlight(BqDETOF)method at HFRS for high-precision in-flight particle identification of radioactive isotope beams on an event-by-event basis.Most importantly,the detector can be utilized for in-ring TOF and position measurements,beam-line TOF measurements at two achromatic foci,and position measurements at a dispersive focus of HFRS,thus making it possible to use two complementary mass measurement methods[isochronous mass spectrometry at the storage ring SRing and magnetic-rigidity–time-of-flight(BqTOF)at the beam-line HFRS]in one single experimental run.

Subdivision of M category for nasopharyngeal carcinoma with synchronous metastasis:time to expand the M categorization system

Introduction:The current metastatic category(M) of nasopharyngeal carcinoma(NPC) is a "catch-all" classification,covering a heterogeneous group of tumors ranging from potentially curable to incurable.The aim of this study was to design an M categorization system that could be applied in planning the treatment of NPC with synchronous metastasis.Methods:A total of 505 NPC patients diagnosed with synchronous metastasis at Sun Yat-sen University Cancer Center between 2000 and 2009 were involved.The associations of clinical variables,metastatic features,and a proposed M categorization system with overall survival(OS) were determined by using Cox regression model.Results:Multivariate analysis showed that Union for International Cancer Control(UICC) N category(N1-3/N0),number of metastatic lesions(multiple/single),liver involvement(yes/no),radiotherapy to primary tumor(yes/no),and cycles of chemotherapy(>4/<4) were independent prognostic factors for OS.We defined the following subcategories based on liver involvement and the number of metastatic lesions:Mia,single lesion confined to an isolated organ or location except the liver;Ml b,single lesion in the liver and/or multiple lesions in any organs or locations except the liver;and M1 c,multiple lesions in the liver.Of the 505 cases,74(14.7%) were classified as Mia,296(58.6%)as M1 b,134(26.5%) as M1 c,and 1 was not specified.The three Ml subcategories showed significant difference in OS[Ml b vs.Mia,hazard ratio(HR) = 1.69,95%confidence interval(CI) = 1.16-2.48,P = 0.007;Ml c vs.Ml a,HR = 2.64,95%CI = 1.75-3.98,P< 0.001],Conclusions:We developed an M categorization system based on the independent factors related to the prognosis of patients with metastatic NPC.This system may be helpful to further optimize individualized care for NPC patients.

Multi-Dimensional Composite Frame as Bifunctional Catalytic Medium for Ultra-Fast Charging Lithium-Sulfur Battery

The shuttle effect of soluble lithium polysulfides(LiPSs)between electrodes and slow reaction kinetics lead to extreme inefficiency and poor high current cycling stability,which limits the commercial application of Li-S batteries.Herein,the multi-dimensional composite frame has been proposed as the modified separator(MCCoS/PP)of Li-S battery,which is composed of CoS_(2) nanoparticles on alkali-treated MXene nanosheets and carbon nanotubes.Both experiments and theoretical calculations show that bifunctional catalytic activity can be achieved on the MCCoS/PP separator.It can not only promote the liquid-solid conversion in the reduction process,but also accelerate the decomposition of insoluble Li_(2)S in the oxidation process.In addition,LiPSs shuttle effect has been inhibited without a decrease in lithium-ion transference numbers.Simultaneously,the MCCoS/PP separator with good LiPSs adsorption capability arouses redistribution and fixing of active substances,which is also beneficial to the rate performance and cycling stability.The Li-S batteries with the MCCoS/PP separator have a specific capacity of 368.6 mAh g^(−1) at 20C,and the capacity decay per cycle is only 0.033%in 1000 cycles at 7C.Also,high area capacity(6.34 mAh cm^(−2))with a high sulfur loading(7.7 mg cm^(−2))and a low electrolyte/sulfur ratio(7.5μL mg^(−1))is achieved.

A Universal Principle to Accurately Synthesize Atomically Dispersed Metal–N_4 Sites for CO_2 Electroreduction

Atomically dispersed metal-nitrogen sites-anchored carbon materials have been developed as effective catalysts for CO2 electroreduction(CO2 ER),but they still suffer from the imprecisely control of type and coordination number of N atoms bonded with central metal.Herein,we develop a family of single metal atom bonded by N atoms anchored on carbons(SAs-M-N-C,M=Fe,Co,Ni,Cu)for CO2 ER,which composed of accurate pyrrole-type M-N4 structures with isolated metal atom coordinated by four pyrrolic N atoms.Benefitting from atomically coordinated environment and specific selectivity of M-N4 centers,SAs-Ni-N-C exhibits superior CO2 ER performance with onset potential of-0.3 V,CO Faradaic efficiency(F.E.) of 98.5%at-0.7 V,along with low Tafel slope of 115 mV dec-1 and superior stability of 50 h,exceeding all the previously reported M-N-C electrocatalysts for CO2-to-CO conversion.Experimental results manifest that the different intrinsic activities of M-N4 structures in SAs-M-N-C result in the corresponding sequence of Ni> Fe> Cu> Co for CO2 ER performance.An integrated Zn-CO2 battery with Zn foil and SAs-Ni-N-C is constructed to simultaneously achieve CO2-to-CO conversion and electric energy output,which delivers a peak power density of 1.4 mW cm-2 and maximum CO F.E.of 93.3%.

3′-Daidzein sulfonate sodium protects against memory impairment and hippocampal damage caused by chronic cerebral hypoperfusion

3′-Daidzein sulfonate sodium（DSS） is a new synthetic water-soluble compound derived from daidzein,a soya isoflavone that plays regulatory roles in neurobiology.In this study,we hypothesized that the regulatory role of DSS in neurobiology exhibits therapeutic effects on hippocampal damage and memory impairment.To validate this hypothesis,we established rat models of chronic cerebral hypoperfusion（CCH） by the permanent occlusion of the common carotid arteries using the two-vessel occlusion method.Three weeks after modeling,rat models were intragastrically administered 0.1,0.2,and 0.4 mg/kg DSS,once a day,for 5 successive weeks.The Morris water maze test was performed to investigate CCH-induced learning and memory deficits.TUNEL assay was used to analyze apoptosis in the hippocampal CA1,CA3 regions and dentate gyrus.Hematoxylin-eosin staining was performed to observe the morphology of neurons in the hippocampal CA1,CA3 regions and dentate gyrus.Western blot analysis was performed to investigate the phosphorylation of PKA,ERK1/2 and CREB in the hippocampal PKA/ERK1/2/CREB signaling pathway.Results showed that DSS treatment greatly improved the learning and memory deficits of rats with CCH,reduced apoptosis of neurons in the hippocampal CA1,CA3 regions and dentate gyrus,and increased the phosphorylation of PKA,ERK1/2,and CREB in the hippocampus.These findings suggest that DSS protects against CCH-induced memory impairment and hippocampal damage possibly through activating the PKA/ERK1/2/CREB signaling pathway.

Charge resolution in the isochronous mass spectrometry and the mass of ^(51)Co

Isochronous mass spectrometry(IMS)of heavyion storage rings is a powerful tool for the mass measurements of short-lived nuclei.In IMS experiments,masses are determined through precision measurements of the revolution times of the ions stored in the ring.However,the revolution times cannot be resolved for particles with nearly the same mass-to-charge(m/q)ratios.To overcome this limitation and to extract the accurate revolution times for such pairs of ion species with very close m/q ratios,in our early work on particle identification,we analyzed the amplitudes of the timing signals from the detector based on the emission of secondary electrons.Here,the previous data analysis method is further improved by considering the signal amplitudes,detection efficiencies,and number of stored ions in the ring.A sensitive Z-dependent parameter is introduced in the data analysis,leading to a better resolution of ^(34)Ar^(18+) and ^(51)Co^(27+) with A/Z=17/9.The mean revolution times of ^(34)Ar^(18+) and ^(51)Co^(27+) are deduced,although their time difference is merely 1.8 ps.The uncorrected,overlapped peak of these ions has a full width at half maximum of 7.7 ps.The mass excess of ^(51)Co was determined to be-27;332e41T keV,which is in agreement with the previous value of-27;342e48T keV.

Simulation of stimulated Raman scattering signal generation in scattering tissues excited by Bessel beams

Stimulated Raman scattering(SRS)microscopy has the ability of noninvasive imaging of specific chemical bonds and been increasingly used in biomedicine in recent years.Two pulsed Gaussian beams are used in traditional SRS microscopes,providing with high lateral and axial spatial resolution.Because of the tight focus of the Gaussian beam,such an SRS microscopy is difficult to be used for imaging deep targets in scattering tissues.The SRS microscopy based on Bessel beams can solve the imaging problem to a certain extent.Here,we establish a theoretical model to calculate the SRS signal excited by two Bessel beams by integrating the SRS signal generation theory with the fractal propagation method.The fractal model of refractive index turbulence is employed to generate the scattering tissues where the light transport is modeled by the beam propagation method.We model the scattering tissues containing chemicals,calculate the SRS signals stimulated by two Bessel beams,discuss the influence of the fractal model parameters on signal generation,and compare them with those generated by the Gaussian beams.The results show that,even though the modeling parameters have great influence on SRS signal generation,the Bessel beams-based SRS can generate signals in deeper scattering tissues.

Chemistry and bioactivities of natural steroidal alkaloids

Steroidal alkaloids possess the basic steroidal skeleton with a nitrogen atom in rings or side chains incorporated as an integral part of the molecule.They have demonstrated a wide range of biological activities,and some of them have even been developed as therapeutic drugs,such as abiraterone acetate(Zytiga®),a blockbuster drug,which has been used for the treatment of prostate cancer.Structurally diverse natural steroidal alkaloids present a wide spectrum of biological activities,which are attractive for natural product chemistry and medicinal chemistry communities.This review comprehensively covers the structural classification,isolation and various biological activities of 697 natural steroidal alkaloids discovered from 1926 to October 2021,with 363 references being cited.

Malignant histiocytosis associated with mediastinal germ cell tumor:A case report

BACKGROUND Germ cell tumors(GCTs)account for 2%of human malignancies but are the most common malignant tumors among males aged 15-35.Since 1983,an association between mediastinal GCT(MGCT)and hematologic malignancies has been recognized.CASE SUMMARY We report a case in which malignant histiocytosis was associated with mediastinal GCTs.The clinical data of a male patient with MGCT admitted to Beijing Children's Hospital were collected retrospectively.The patient was first diagnosed according to imaging and pathological features as having MGCT,and was treated with surgery and chemotherapy.One year after stopping chemotherapy,imaging showed metastases in the right supraclavicular,mediastinum,hilar region and retroperitoneal lymph node,right pleura,right lung,and right para-cardiac margin.Pathological diagnosis of the liver nodular and hilar lymph nodes included systemic juvenile xanthogranuloma and Rosai-Dorfman lesions with malignant transformation(i.e.,morphological characteristics and immunophenotype of histiocytic sarcoma).Following diagnosis,the patient accepted chemotherapy with vindesine,cytarabine and dexamethasone.Positron emission tomography–computed tomography showed partial remission.The patient was followed-up for 10 mo after the diagnosis of malignant histiocytosis,and no sign of progression or relapse was observed.CONCLUSION Physicians should recognize the possibility of hematologic malignancies being associated with MGCT.Suitable sites should be selected for pathological examination.

A Robust Noninvasive Approach to Study Gut Microbiota Structure of Amphibian Tadpoles by Feces

The 16S rDNA amplicon high-throughput sequencing technique provides a robust and inexpensive approach to detect the gut microbiota of amphibians. Since different experimental protocols generate technical biases in drawing the gut microbiota profiles, the integrative analysis of gut microbiota produced by different studies must be performed with circumspection. In this study, we compared the efficacy of two DNA extraction methods （i.e., a phenol-chloroform method and TIANamp Stool DNA Kit） in describing intestinal and fecal bacterial communities of transplanted Asiatic toad （Bufo gargarizans） tadpoles. In terms of the DNA extraction quality （i.e., DNA purity and yield rate） and the consistency in between fecal and intestinal microbiota structures （i.e., a and 13 diversity indices）, the phenol-chloroform method was more robust than this commercial stool kit in profiling gut microbiota of tadpoles with feces.

Supercontinuum fiber laser-based coherent anti-Stokes Raman scattering microscopy for label-free chemical imaging

Coherent anti-Stokes Raman scattering(CA RS)microscopy can resolve the chemical compo-nents and distribution of living biological systems in a label-firee manner and is favored in several disciplines.Current CA RS microscopes typically use bulky,high-performance solid-state lasers,which are expensive and sensitive to environmental changes.With their relatively low cost and environmental sensitivity,supercontinum fiber(SF)lasers with a small footprint have found increasing use in biomedical applications.Upon these features,in this paper,we homebuilt a low-cost CARS microscope based on a SF laser module(scCA RS microscope).This SF laser module is specially customized by adding a time synchronized seed source channel to the SF laser to form a dual-channel output laser.The performance of the scCARS microscope is evaluated with dimethyl sulfoxide,whose results confirm a spatial resolution of better than 500nm and a detection sensitivity of millimolar concentrations.The dual-color imaging capability is further demonstrated by imaging different species of mixed microspheres.We finally explore the potential of our scCARS microscope by mapping lipid droplets in different cancer cells and corneal stromal lenses.

Luteolin protects PC12 cells from rotenone-induced apoptosis

The 4-hydroxy-flavonoid compound luteolin is a phytoestrogen with antioxidant, anti-inflammatory, and anti-tumor properties. The present study analyzed the protective effects of luteolin against rotenone-induced PC12 cell apoptosis in a model of Parkinson＇s disease （PD）. Rotenone （1.6 μmol/L） was utilized to establish the In vitro PD model, resulting in low cell viability and an apoptotic rate of 36.1%. Luteolin （100 μmol/L） pretreatment significantly ameliorated rotenone-induced damage, improved cell morphology and viability, decreased comet tail length, reduced the rate of apoptosis （11.8%）, and down-regulated cleaved caspase-3 expression. Results demonstrate that luteolin protects PC12 cells against rotenone-induced apoptosis by decreasing cleaved caspase-3 expression.

Accurate capacitance-voltage characterization of organic thin films with current injection

To deal with the invalidation of commonly employed series model and parallel model in capacitance-voltage(C-V)characterization of organic thin films when current injection is significant,a three-element equivalent circuit model is proposed.On this basis,the expression of real capacitance in consideration of current injection is theoretically derived by small-signal analysis method.The validity of the proposed equivalent circuit and theoretical expression are verified by a simulating circuit consisting of a capacitor,a diode,and a resistor.Moreover,the accurate C-V characteristic of an organic thin film device is obtained via theoretical correction of the experimental measuring result,and the real capacitance is 35.7%higher than the directly measured capacitance at 5-V bias in the parallel mode.This work strongly demonstrates the necessity to consider current injection in C-V measurement and provides a strategy for accurate C-V characterization experimentally.