Selective tropism of liver stem cells to hepatocellular carcinoma in vivo

AIM: To investigate the selective tropism of liver stem cells to hepatocellular carcinoma (HCC) in an animal model and its feasibility as a vector to deliver therapeutic genes for targeted therapy of HCC. METHODS: WB-F344, a kind of rat liver stem cell, was infected with recombinant virus to establish a cell line with stable, high-level expressing enhanced green fluorescent protein (EGFP). An animal model of HCC in Wistar rats was established by implanting HCC cells (CBRH7919) combined with an immunosuppressive drug. EGFP labeled liver stem cells were injected into caudal veins of the animals and distribution was observed at different time points after injection. SDF-1 and c-kit expression in non-tumor liver and tumor tissue were analysed by immunohistochemistry for the relationshiop between the expression and migration of liver stem cells. Furthermore, hepatic stem cells were injected via the portal vein, hepatic artery, caudal vein, or directly into the pericancerous liver tissue, respectively, and effects on migration, localization, and proliferation of the hepatic stem cells within the tumor tissue were observed and analyzed. RESULTS: Recombinant adenovirus could deliver the EGFP gene to hepatic stem cells. A new stem cell line, named WB-EGFP, was established that stably expressed EGFP. WB-EGFP cells still showed selective tropism towards HCC and EGFP expression was stable in vivo. According to immunohistochemistry results, SDF-1 may not be related to the mechanisms of tropism of hepatic stem cells. Different application sites affected the distribution of liver stem cells. Injection via the portalvein was superior with regard to selective migration, localization, and proliferation of the hepatic stem cells within the tumor tissue. CONCLUSION: Liver stem cells have the biological behavior of selective migration to HCC in vivo and they could localize and proliferate within HCC tissue stably expressing the target gene. Liver stem cells are a potential tool for a targeted gene therapy of HCC.

Influence of different portal vein branches on hepatic encephalopathy during intrahepatic portal shunt via jugular vein

This letter is regarding the study titled‘Targeted puncture of left branch of intrahepatic portal vein in transjugular intrahepatic portosystemic shunt(TIPS)to reduce hepatic encephalopathy’.Prior to the approval of TIPS dedicated stents(Viatorr stents)in China in October 2015,Fluency covered stents were typically used.As Fluency covered stents have a strong support force and axial elastic tension,a‘cap’may form if the stent is located too low at the end of the hepatic vein or too short at the end of the portal vein during surgery,leading to stent dysfunction.Since the blood shunted by the stent is from the main trunk of the portal vein,the correlation between the incidence of postoperative hepatic encephalopathy and the location of the puncture target(left or right portal vein branch)is worth discussion.Notably,no studies in China or foreign countries have proven the occurrence of left and right blood stratification after the accumulation of splenic vein and mesenteric blood flow in the main trunk of the portal vein in patients with cirrhotic portal hypertension.

生育动机的世代与性别差异分析基于CFPS2020数据

当前中国的低生育率问题已成为公认的事实,其中,生育观念的转变具有关键性影响。生育动机是生育观念的重要构成部分,本文聚焦“为什么要生养子女”这一问题,考察生育动机的世代与性别差异。基于中国家庭追踪调查2020年(CFPS2020)的数据,本研究将生育动机划分为“低意愿与消极”“个体导向为主”“双导向情感型”“家庭导向为主”四类。研究发现,超过一半的中国居民仍具有家庭导向为主的生育动机,但存在世代差异,且已发生根本性的代际转变。在“80后”“90后”中,以家庭导向为主的生育动机逐渐丧失主导地位,个体导向为主的生育动机大幅度增加。另外,男性的生育动机比女性更加传统。随着出生世代的变化,男女在生育动机上的差异存在扩大的趋势,本研究从教育获得变迁的角度对此提供了可能的解释。

Microwave Drying of Scots Pine Lumber:Structure Changes,Its Effect on Liquid Permeability

Microwave(MW)drying method was adopted to enhance the liquid permeability of Scots pine lumber.Structure changes were characterized by stereoscope microscope,scanned electron microscope(SEM)and transmission electron microscope(TEM)examination.Pore parameters before and after MW treatment were detected by mercury intrusion porosimetry(MIP)method,and the effect of structure changes on liquid permeability were analyzed.As stereoscope microscope,SEM and TEM examination results showed,macro and micro checks mainly developed at intercellcular of tracheids,intercellular of ray parenchyma and tracheid,while these checks extend main along the radial-longitudinal plane.Pit border destruction,aspirated pits’orus translocation and micro-checks in tracheid cell wall were also observed.MIP test shown that pore volume and pore area increased as macro and micro checks generated to form new cavities.Microstructure changes would increase the quantity of pores or enlarge the pore diameter.Liquid flow pathways increased as macro and micro checks generated,aspirated pits reopened to form new pathways;liquid flow efficiency improved as porosity,pore volume and pore diameter increased which facilitated the liquid flow.

人类颜色和运动知觉的事件相关功能磁共振成像

目的 :利用新近发展起来的事件相关功能磁共振成像技术探测人类颜色和运动知觉区的特点。材料和方法 :用1.5T磁共振成像系统对 7名受试者行扫描。颜色刺激和运动刺激随机呈现。数据经预处理和统计分析获得脑激活图和局部血氧反应曲线。结果 :颜色刺激主要激活第四视觉区 (V4) ,但颞中回复合体 + (MT+ )也有轻度激活 ;运动刺激主要激活MT+ ,但V4也有一定激活。结论 :尽管V4主要参与颜色知觉 ,但在一定程度上也可参与运动知觉 ;类似地 ,尽管MT+ 的主要功能是运动知觉 ,但在一定程度上也参与颜色知觉的加工。事件相关方法可能比组块设计更为灵敏。

地下水氯代烃污染修复技术研究进展

氯代烃作为重要的化工原料被广泛应用,使用过程中的跑冒滴漏已使其成为地下水中最常检测出的有毒有害污染物之一,严重影响人体健康与生态环境安全.为更清楚地了解地下水中氯代烃污染特点与修复技术发展现状,首先对地下水中氯代烃迁移转化特征进行梳理,分析并总结氯代烃多相态、多介质赋存状态以及影响其迁移转化的因素;其次,归纳阐述不同赋存状态下氯代烃适用的修复技术,包括试验研究与实际场地修复方面的研究进展以及修复过程中存在的问题;最后,结合当前研究现状,对氯代烃修复技术的发展方向进行展望.调查研究表明,PRB技术墙体新介质、缓释氧化剂及污染物靶向修复材料的开发、高抗性且生存能力强的工程菌培育以及修复技术之间的联用将是地下水氯代烃污染治理的发展方向;同时,在修复技术的选择与联用上,必须遵循技术与场地水文地质条件相适应的修复思路.

危险废物填埋场地下水污染风险评价中指标权重计算方法优化比选

为了探究适用于危险废物填埋场地下水污染风险评价的指标权重计算方法,选用层次分析法、熵权法、层次分析-熵权法进行计算,并通过我国37家危险废物填埋场地下水污染风险评价结果与地下水中苯浓度的拟合验证对权重计算方法进行分析比选.结果表明:①3组权重计算结果中,含水层渗透系数和包气带渗透系数均为最重要的指标,危险废物填埋场所处地层介质类型是影响地下水污染风险最显著的因素.在建设危险废物填埋场时,选址需优先关注含水层及包气带介质类型,必要时应采取更高性能的防渗技术手段;②3组场地风险指数(R)和污染指数(C)线性拟合R^(2)值排序为层次分析-熵权法(R^(2)=0.84)>层次分析法(R^(2)=0.75)>熵权法(R^(2)=0.51),因此采用层次分析-熵权法得出的危险废物填埋场地下水污染风险评价结果与实际污染状况匹配度更高,构建的风险评价方法更能准确预测地下水污染风险;③当各指标权重由大到小依次加和至总权重为0.96时,层次分析-熵权法可包含12项指标,且权重分配更为均衡,不易受到单个指标缺失的影响,由此建立的综合指数计算方法更加可靠.研究显示,层次分析-熵权法是更适用于危险废物填埋场地下水污染风险评价的指标权重计算方法,构建的污染风险评价方法结果准确、易操作,在一定程度上可为危险废物填埋场地下水污染的风险评价及运行管理提供支持.

Treatment of chronic proliferative cholangitis with c-myc shRNA

AIM: To investigate the feasibility and effectiveness of c-myc shRNA in inhibiting the hyperplastic behavior and lithogenic potentiality of chronic proliferative cholangitis (CPC), in order to prevent stone recurrence and biliary restenosis.METHODS: An animal model of CPC was established by giving intralumenally 0.5 mL of c-myc shRNA. Then, the effects of c-myc shRNA on hyperplastic behavior and lithogenic potentiality of CPC were evaluated by histological observation, immunohistochemistry, real-time PCR and Western blotting for c-myc, proliferating cell nuclear antigen (PCNA), procollagen TM mucin5AC, enzymatic histochemistry for β-glucuronidase, and biochemistry for hydroxyproline in the diseased bile duct.RESULTS: Treatment with c-myc shRNA efficiently suppressed the hyperplasia of biliary epithelium, submucosal gland, and collagen fiber by inhibiting mRNA and protein expression of c-myc. More importantly, it decreased the lithogenic potentiality of CPC by inhibiting the expression of mucin 5AC and the secretion of endogenous β-glucuronidase. Further investigation indicated that c-myc shRNA-3 had a better inhibitory effect on CPC.CONCLUSION: Treatment with c-myc shRNA-3 can control CPC and reduce the lithogenic potentiality of CPC.

Isogeometric Analysis with Local Adaptivity for Vibration of Kirchhoff Plate

Based on our proposed adaptivity strategy for the vibration of Reissner-Mindlin plate,we develop it to apply for the vibration of Kirchhoff plate.The adaptive algorithm is based on the Geometry-Independent Field approximaTion(GIFT),generalized from Iso-Geometric Analysis(IGA),and it can characterize the geometry of the structure with NURBS(Non-Uniform Rational B-Splines),and independently apply PHT-splines(Polynomial splines over Hierarchical T-meshes)to achieve local refinement in the solution field.TheMAC(Modal AssuranceCriterion)is improved to locate unique,as well as multiple,modal correspondence between different meshes,in order to deal with error estimation.Local adaptivity is carried out by sweeping modes from low to high frequency.Numerical examples showthat a proper choice of the spline space in solution field(with GIFT)can deliver better accuracy than using NURBS solution field.In addition,for vibration of heterogeneous Kirchhoff plates,our proposed method indicates that the adaptive local h-refinement achieves a better solution accuracy than the uniform h-refinement.

Analysis on Present Situation of Anaerobic Digestion Products of Sludge in Landscaping Application and Market Demand in Chongqing

Taking the anaerobic digestion products of sludge as the object, through the analysis on the development of garden substrate market at home and abroad and the development status of horticultural products from the anaerobic digestion products, the direction for the utilization of the anaerobic digestion products of sludge was pointed out. Based on the demand of Chongqing’s garden market, this paper analyzed the potential utilization of sludge anaerobic digestion products in Chongqing, and briefly introduced the research status of landscaping utilization of sludge anaerobic digestion products in Chongqing, in order to provide reference for the industry.

Evolutionary PSO-based emergency monitoring geospatial edge service chain in the emergency communication network

Emergency communication networks play a vital role in disaster monitoring,transmission,and application during disaster emergency response(DER),however,the performance and stability of edge nodes in the emergency communication networks are often weak due to limited communication and computation resources.This weakness directly affects the quality,of service(Qos)of the geospatial edge service(GES)chains involved in emergency monitoring.Existing research predominantly addresses service compositions in stable environments,neglecting the aggregation of efficient and robust GES chains in emergency communication networks.This study proposes an evolutionary_particie swarm optimization(EPSO)-based emergency monitoring GES chain in an_emergency communication network.it includes a GES chain model of emergency environment monitoring for tailing areas,as well as the designs of the particle chromosome encoding method,fitness evaluation model,and particle chromosome swarm update operators of the EPSO-based GES chain.Finally,the study conducts emergency environment monitoring experiments for tailing areas using the proposed method.Experiments results demonstrate that the proposed method significantly enhances the efficiency,stability,and reliability of emergency monitoring GEs chains in the emergency communication network.This is crucial to providing fast and reliable services for DER during natural disasters.

Quantitative Estimation on Methane Storage Capacity of Organic-Rich Shales from the Lower Silurian Longmaxi Formation in the Eastern Sichuan Basin, China

The assessment of gas storage capacity is crucial to furthering shale gas exploration and development in the eastern Sichuan Basin,China.Eleven organic-rich shale samples were selected to carry out the high pressure methane sorption,low-pressure N_(2)/CO_(2) gas adsorption,and bulk and skeletal density measurements to investigate the methane storage capacity(MSC).Based on the relative content of clay,carbonates,quartz+feldspar,we grouped the 11 samples into three lithofacies:silica-rich argillaceous shale(CM-1),argillaceous/siliceous mixed shale(M-2),and clay-rich siliceous shale(S-3).The total porosity of the shale samples varies from 3.4% to 5.6%,and gas saturation ranges from 47% to 89%.The measured total gas amount ranges from 1.84 mg/g to 4.22 mg/g with the ratio of free gas to total gas amount ranging from 52.7% to 70.8%.Free gas with high content in the eastern Sichuan Basin may be the key factor controlling amount of shale gas production.The TOC content critically controls the MSC of shales,because micropore,mesopore volumes and the specific surface areas associated with organic matter provide the storage sites for the free and adsorbed gas.The methane sorption capacities of samples from different lithofacies are also affected by clay minerals and moisture content.Clay minerals can provide additional surface areas for methane sorption,and water can cause a 7.1%-42.8% loss of methane sorption capacity.The total porosity,gas-bearing porosity,water saturation,free gas and adsorbed gas number of samples from different lithofacies show subtle differences if the shale samples had similar TOC contents.Our results suggest that,in the eastern Sichuan Basin,clay-rich shale lithofacies is also prospecting targets for shale gas production.

Peripheral CD4^(+) T cell signatures in predicting the responses to anti-PD-1/PD-L1 monotherapy for Chinese advanced non-small cell lung cancer

Limited benefit population of immune checkpoint inhibitors makes it urgent to screen predictive biomarkers for stratifying the patients.Herein,we have investigated peripheral CD4^(+) T cell signatures in advanced non-small cell lung cancer(NSCLC)patients receiving anti-PD-1/PD-L1 treatments.It was found that the percentages of IFN-γand IL-17A secreting naïve CD4^(+) T cells(Tn),and memory CD4^(+) T cells(Tm)expressing PD-1,PD-L1 and CTLA-4 were significantly higher in responder(R)than non-responder(NonR)NSCLC patients associated with a longer progression free survival(PFS).Logistic regression analysis revealed that the baseline IFN-γ-producing CD4^(+) Tn cells and PD-1^(+)CD4^(+) Tm cells were the most significant signatures with the area under curve(AUC)value reaching 0.849.This was further validated in another anti-PD-1 monotherapy cohort.Conversely,high percentage of CTLA-4^(+)CD4^(+) Tm cells was associated with a shorter PFS in patients receiving anti-PD-L1 monotherapy.Our study therefore elucidates the significance of functional CD4^(+) Tn and Tm subpopulations before the treatment in predicting the responses to anti-PD-1 treatment in Chinese NSCLC patients.The fact that there display distinct CD4^(+) T cell signatures in the prediction to anti-PD-1 and anti-PD-L1 monotherapy from our study provides preliminary evidence on the feasibility of anti-PD-1 and anti-PD-L1 combination therapy for advanced NSCLC patients.

Selectivity of N170 in the left hemisphere as an electrophysiological marker for expertise in reading Chinese

Objective The left-lateralized N170, an event-related potential component consistently shown in response to alphabetic words, is a robust electrophysiological marker for reading expertise in an alphabetic language. In contrast, such a marker is lacking for expertise in reading Chinese, because the existing results about the lateralization of N170 for Chinese characters are mixed, reflecting complicated factors such as top-down modulation that contribute to the relative magnitudes of N170 in the left and right hemispheres. The present study aimed to explore a potential electrophysiological marker for reading expertise in Chinese with minimal top-down influence. Methods We recorded N170 responses to Chinese characters and three kinds of control stimuli in a content-irrelevant task, minimizing potential top-down effects. Results Direct comparison of the N170 amplitude in response to Chinese characters between the hemispheres showed a marginally significant left-lateralization effect. However, detailed analyses of N170 in each hemisphere revealed a more robust pattern of left-lateralization - the N170 in the left but not the right hemisphere differentiated Chinese characters from control stimuli. Conclusion These results suggest that the selectivity of N170 （a greater N170 in response to Chinese characters than to control stimuli） within the left hemisphere rather than the hemispheric difference of N170 with regard to Chinese characters is an electrophysiological marker for expertise in reading Chinese.

Main Mechanism for Generating Overpressure in the Paleogene Source Rock Series of the Chezhen Depression,Bohai Bay Basin, China

The Chezhen depression,located in the south of Bohai Bay Basin,is an oil-producing basin in China. The third and fourth members of the Shahejie Formation(E(s3) and E(s4)) are the main source rock series in the Chezhen depression. Widespread overpressures occurred in the E(s3) and E(s4) from the depths of approximately 2 000 to 4 600 m,with the maximum pressure coefficient of 1.98 from drillstem tests(DST). Among the sonic,resistivity and density logs,sonic-log is the only reliable pressure indicator and can be used to predict the pore pressure with Eaton's method. All the overpressured mudstones in the source rock series have higher acoustic traveltimes compared with normally pressured mudstones at a given depth. The overpressured mudstones in the E(s3) and E(s4) units are characterized by a normal geothermal gradient,high average density values up to 2.5 g/cm^3,strong present-day hydrocarbon generation capability,abundant mature organic matter and high contents of residual hydrocarbons estimated by the Rock-Eval S1 values and chloroform-soluble bitumen "A" values. All suggest that the dominant mechanism for overpressure in the mudstones of source rock series in the Chezhen depression is hydrocarbon generation. A comparison between the matrix porosity of the normally pressured sandstones and overpressured sandstones,the quantitative evaluation of porosity loss caused by compaction and the conventional thin section inspection demonstrate that the sandstones in the Chezhen depression were normally compacted. The high contents of hydrocarbons in the overpressured reservoirs prove that the overpressure in the sandstones of the source rock series was caused by pressure transmission from the source rocks.

Fluid Inclusion and Geochemistry Studies of Calcite Veins in Shizhu Synclinorium,Central China:Record of Origin of Fluids and Diagenetic Conditions

Calcite veins in carbonate fracture have been investigated by petrographic, fluid inclusion, geochemical analyses and coupled with basin modeling techniques to provide useful insights into fluid activity and deformation conditions of the Cambrian to Triassic Shizhu synclinorium from the western region of Mid-Yangtze, central China. The results of the fluid inclusion microthermometry show a wide range of homogenization temperatures（78.6–215.5 °C） and salinities（0.18–23.11 wt.% NaCl equivalent）, indicating the formation under diverse fluid conditions. All the calcite veins have negative Ce anomalies, which are the typical characteristic of marine carbonate sediments; it is therefore plausible that calcite veins were precipitated from the marine basin fluid. The stable carbon isotopic compositions of calcites（δ^（13）CV-PDB=-2.5‰–4.26‰） and host limestones（δ^（13）CV-PDB=-3.56‰–5.80‰） are very similar with a correlation coefficient of 0.86, however, four calcites from the Lower Permian and Lower Triassic show lower δ^（13）C values relative to the host limestones, and they are depleted in total REE concentrations（∑REE ratio varies from 0.74 to 2.06）, suggesting the derivation of dissolved carbon from marine carbonates hosting the calcite veins and, less commonly, from the degradation of organic matter. Calculated δ^（18）O of the fluids-precipitating calcites（δ^（18）OV-SMOW=-0.41‰–14.42‰）, ^（87）Sr/^（86）Sr ratios varying in the range of coeval seawater and the distinct REE pattern simultaneously suggest calcite-forming fluids in each stratigraphic unit could have formed from the involvement of fluids that originated from coeval seawater and evolved through different degrees of water rock interaction. However, the presence of more radiogenic ^（87）Sr/^（86）Sr ratios than coeval seawater and pronounced positive Eu anomalies in calcites of Lower to Middle Ordovician rocks indicate that terrestrial input from upper strata mudstone and siliciclastic rocks could be involved in the precipitation of the Ordovician calcite. Fluid-inclusion data combined with burial and thermal history modeling indicate there was large-scale flow of evolved basinal fluids through the carbonate formation fractures spanning a time frame from 135 to 50 Ma（Early Cretaceous–Eocene）. Therefore, the geochemical characteristics of calcite veins can provide the basis for deformation events in Late Yanshanian and Early Himalayan orogeny.

Apoptosis of mesenchymal stem cells is regulated by Rspo1 via the Wnt/β-catenin signaling pathway

Objective: The aim of this study was to investigate the effect and possible mechanism of action of roof plate-specific spondin1 (Rspo1) in the apoptosis of rat bone marrow mesenchymal stem cells (BMSCs). Methods: Osteogenic and adipogenic differentiation of BMSCs was identified by Alizarin Red and Oil Red O staining, respectively. BMSC surface markers (cluster of differentiation 29 [CD29], CD90, and CD45) were detected using flow cytometry. BMSCs were transfected with an adenoviral vector encoding Rspo1 (BMSCs-Rspo1 group). The expression levels of Rspo1 gene and Rspo1 protein in the BMSCs-Rspo1 group and the two control groups (untransfected BMSCs group and BMSCs-green fluorescent protein [GFP] group) were analyzed and compared by quantitative polymerase chain reaction and Western blot. The occurrence of apoptosis in the three groups was detected by flow cytometry and acridine orange-ethidium bromide (AO-EB) double dyeing. The activity of the Wnt/β-catenin signaling pathway was evaluated by measuring the expression levels of the key proteins of the pathway (β-catenin, c-Jun N-terminal kinase [JNK], and phospho-JNK). Results: Osteogenic and adipogenic differentiation was confirmed in cultured BMSCs by the positive expression of CD29 and CD90 and the negative expression of CD45. Significantly increased expression levels of Rspo1 protein in the BMSCs-Rspo1 group compared to those in the BMSCs (0.60 ± 0.05 vs. 0.13 ± 0.02;t=95.007, P=0.001) and BMSCs-GFP groups (0.60 ± 0.05 vs. 0.10 ± 0.02;t=104.842, P=0.001) were observed. The apoptotic rate was significantly lower in the BMSCs-Rspo1 group compared with those in the BMSCs group ([24.06 ± 2.37]% vs.[40.87 ± 2.82]%;t =49.872, P =0.002) and the BMSCs-GFP group ([24.06 ± 2.37]% vs.[42.34 ± 0.26]%;t =62.358, P =0.001). In addition, compared to the BMSCs group, the protein expression levels of β-catenin (2.67 ± 0.19 vs. 1.14 ± 0.14;t =-9.217, P =0.000) and JNK (1.87 ± 0.17 vs. 0.61 ± 0.07;t =-22.289, P =0.000) were increased in the BMSCs-Rspo1 group. Compared to the BMSCs-GFP group, the protein expression levels of β-catenin (2.67 ± 0.19 vs. 1.44 ± 0.14;t =-5.692, P =0.000) and JNK (1.87 ± 0.17 vs. 0.53 ± 0.06;t =-10.589, P =0.000) were also upregulated in the BMSCs-Rspo1 group. Moreover, the protein expression levels of phospho-JNK were increased in the BMSCs-Rspo1 group compared to those in the BMSCs group (1.89 ± 0.10 vs. 0.63 ± 0.09;t =-8.975, P =0.001) and the BMSCs-GFP group (1.89 ± 0.10 vs. 0.69 ± 0.08;t =-9.483, P =0.001). Conclusion: The Wnt/β-catenin pathway could play a vital role in the Rspo1-mediated inhibition of apoptosis in BMSCs.

Occurrence Characteristics of Saline-Lacustrine Shale-Oil in the Qianjiang Depression,Jianghan Basin,Central China

The amount of shale oil and its characterization are key issues in the study of shale oil.At present,many scholars use a variety of methods to evaluate the amount of shale oil,and use the calculated amount of hydrocarbons to analyze its influencing factors;however,there is lack of detailed research on the storage space for shale-oil and it’s influencing factors.In view of this issue,gas chromatography(GC),gas chromatography-mass spectrometry(GC-MS),soxhlet extraction(SE),fieldemission scanning electron microscopy(FE-SEM),low-temperature nitrogen adsorption(LTNA),highpressure mercury intrusion(HPMI),and X-ray diffraction(XRD)were used to analyze and compare samples from two wells located in different deposition locations.The unconventional Well BYY2 and BX7 s were drilled in the depocenter and distal area of the Qianjiang Formation,respectively.Controlled by differences in the organic matter type and sedimentary environment,the organic matter in Well BYY2,which was found to be characterized by laminar shale,mainly originated from aquatic algae.The results showed that as the total organic carbon(TOC)content increased,the amount of shaleoil in the pores increased.Shale-oil was mostly stored in mesopores and macropores that had been preserved by dolomite minerals of a biogenic origin and also occurred in pores sized 5–200 nm and>1μm.Dolomite minerals of a biogenic origin and clay minerals contributed to the occurrence of shaleoil.In comparison,the organic matter in Well BX7 has been greatly influenced by terrestrial organic matter.Pores in the massive mudstones from Well BX7 were determined to be mainly mesopores preserved by clay minerals and quartz,and the shale-oil was mostly stored within the pores of<40 nm.When the TOC content was~2.5 wt.%,the generated shale-oil reached saturation.Clay minerals contributed to the occurrence of shale-oil,whereas quartz only contributed to the occurrence of shale-oil in macropores.

Revisiting Rhenium-Osmium Isotopic Investigations of Petroleum Systems: From Geochemical Behaviours to Geological Interpretations

Recent decades have witnessed an increasing number of studies investigating petroleum systems with the application of rhenium-osmium(Re-Os) isotopic geochemistry. Here, we review the use of the 187 Re-187 Os geochronometer with respect to the geochemical behaviour of rhenium and osmium in hydrocarbon-related geological processes. The Re-Os budget in hydrocarbon source rock predominantly originates from natural water columns during its deposition. Open seawater tends to have a homogeneous Os isotopic composition because its residence time in seawater is longer than the time taken for ocean mixing. On the contrary, restricted water bodies(e.g., lakes) may have heterogeneous Os isotopic compositions due to the greater amount of terrigenous input. Hydrogenous Re and Os atoms are sequestered from the water body into sedimentary organic matter and transferred into crude oil through thermal maturation of organic matter. Thermal maturation likely does not significantly alter the Re-Os isotopic systematics of the source rock as a Re-Os isochron age of 442±21 Ma(2σ) is yielded in this study for over matured source rocks within the Silurian Longmaxi Formation from the Sichuan Basin. Re-Os atoms are mainly hosted by the highly polar/aggregating/aromatic asphaltenes in hydrocarbons, possibly chelating with organic complexes or occurring as metalloporphyrins. Resin and aromatic hydrocarbons also contribute to the Re-Os budget, but are 2 to 3 orders of magnitude lower than that of asphaltenes, whereas saturates do not contain appreciable Re-Os contents. The distribution of Re-Os atoms in hydrocarbons is heterogeneous because the duplicate analysis of pure single bitumen samples yields similar ^(187)Os/^(188)Os ratios whereas variable ^(187)Re/^(188)Os ratios. The Re-Os system in crude oils can be reset during transport away from the source rocks, with Os-rich organic fractions more readily expelled than Re-rich fractions. Contact with metal-rich fluids(e.g., hydrothermal fluid) or compositional changes related to asphaltene contents(e.g., deasphalting, biodegradation, thermal cracking and thermochemical sulphate reduction) are also likely to alter the Re-Os systematics in hydrocarbons. These geochemical features enable the ^(187)Re-^(187)Os isotopic system to have robust applicability for petroleum system investigations, which may use the Re-Os radiometric tool for:(1) stratigraphic correlation of source rocks,(2) dating geological events altering the asphaltene content in hydrocarbon such as hydrocarbon generation, thermochemical sulphate reduction, etc., and,(3) fingerprinting hydrocarbons. Regardless of the robustness of the ^(187)Re-^(187)Os geochronometer for petroleum system investigations, there are several pending questions such as partitioning between solid organic species or between organic matter and sulphide, chelating sites in hydrocarbons and Os isotopic equilibration between hydrocarbon subfractions. To improve the understanding of the Re-Os behaviour in petroleum systems, we underscore multi-proxies-based geochemistry(e.g., inorganic-organic geochemistry) and experimental studies(e.g., hydrous pyrolysis).

Public Emotional Diffusion over COVID-19 Related Tweets Posted by Major Public Health Agencies in the United States

Since the end of 2019,the COVID-19 outbreak worldwide has not only presented challenges for government agencies in addressing public health emergency,but also tested their capacity in dealing with public opinion on social media and responding to social emergencies.To understand the impact of COVID-19 related tweets posted by the major public health agencies in the United States on public emotion,this paper studied public emotional diffusion in the tweets network,including its process and characteristics,by taking Twitter users of four official public health systems in the United States as an example.We extracted the interactions between tweets in the COVID-19-Tweet Ids data set and drew the tweets diffusion network.We proposed a method to measure the characteristics of the emotional diffusion network,with which we analyzed the changes of the public emotional intensity and the proportion of emotional polarity,investigated the emotional influence of key nodes and users,and the emotional diffusion of tweets at different tweeting time,tweet topics and the tweet posting agencies.The results show that the emotional polarity of tweets has changed from negative to positive with the improvement of pandemic management measures.The public’s emotional polarity on pandemic related topics tends to be negative,and the emotional intensity of management measures such as pandemic medical services turn from positive to negative to the greatest extent,while the emotional intensity of pandemic related knowledge changes the most.The tweets posted by the Centers for Disease Control and Prevention and the Food and Drug Administration of the United States have a broad impact on public emotions,and the emotional spread of tweets’polarity eventually forms a very close proportion of opposite emotions.