期刊文献+
共找到456,658篇文章
< 1 2 250 >
每页显示 20 50 100
The challenge of molecular selection in liver-limited metastatic colorectal cancer for surgical resection: a systematic review and meta-analysis in the context of current and future approaches
1
作者 ROSSANA RONCATO JERRY POLESEL +11 位作者 FEDERICA TOSI ELENA PERUZZI ERIKA BRUGUGNOLI CLAUDIA LAURIA PANTANO MARIA FURFARO FILIPPO DI GIROLAMO ALESSANDRO NANI ARIANNA PANI NOEMI MILAN ELENA DE MATTIA ANDREA SARTORE-BIANCHI ERIKA CECCHIN 《Oncology Research》 SCIE 2024年第9期1407-1422,共16页
Objectives:Treatment of metastatic colorectal cancer(mCRC)includes resection of liver metastases(LM),however,no validated biomarker identifies patients most likely to benefit from this procedure.This meta-analysis aim... Objectives:Treatment of metastatic colorectal cancer(mCRC)includes resection of liver metastases(LM),however,no validated biomarker identifies patients most likely to benefit from this procedure.This meta-analysis aimed to assess the impact of the most relevant molecular alterations in cancer-related genes of CRC(i.e.,RAS,BRAF,SMAD4,PIK3CA)as prognostic markers of survival and disease recurrence in patients with mCRC surgically treated by LM resection.Methods:A systematic literature review was performed to identify studies reporting data regarding survival and/or recurrence in patients that underwent complete liver resection for CRC LM,stratified according to RAS,BRAF,PIK3CA,and SMAD4 mutational status.Hazard ratios(HRs)from multivariate analyses were pooled in the meta-analysis and various adjustment strategies for confounding factors were combined.The search was conducted in numerous databases,including MEDLINE(PubMed),Embase,Cumulative Index to Nursing and Allied Health Literature(CINAHL)(EBSCO host),and WHO Global Index Medicus,through March 18th,2022.Meta-analyses,editorials,letters to the editor,case reports,studies on other primary cancers,studies with primary metastatic sites other than the liver,studies lacking specific oncological outcome variables or genetic data,non-English language studies,and studies omitting residual disease data from liver metastasectomy were excluded.The remaining 47 studies were summarized in a descriptive table which outlines the key characteristics of each study and final results were graphically presented.Results:RAS mutation status was negatively associated with overall survival(OS)(HR,1.68;95%CI,1.54–1.84)and recurrence free survival(RFS)(HR,1.46;95%CI,1.33–1.61).A negative association was also found for BRAF regarding OS(HR,2.64;95%CI,2.15–3.24)and RFS(HR,1.89;95%CI,1.32–2.73)and SMAD4 regarding OS(HR,1.93;95%CI,1.56–2.38)and RFS(HR,1.95;95%CI,1.31–2.91).For PIK3CA only three studies were eligible and no significant association with either OS or RFS could be highlighted.Conclusion:RAS,BRAF,and SMAD4 are negatively associated with OS and RFS in patients undergoing curative liver metastasectomy from colorectal cancer.No conclusion can be drawn for PIK3CA due to the limited literature availability.These data support the integration of RAS,BRAF,and SMAD4 mutational status in the surgical decision-making for colorectal liver metastasis.Nevertheless,we have to consider several limitations,the major ones being the pooling of results from studies that evaluated patient outcomes as either disease-free survival(DFS)or RFS;the inclusion of patients with minimal residual disease and unconsidered potential confounding factors,such as variability in resectability definitions,chemotherapy use,and a potential interaction between biological markers and pre-and post-resection pharmacological treatments. 展开更多
关键词 METASTASECTOMY Liver metastases RAS BRAF SMAD4 PIK3CA COLORECTAL
下载PDF
Assessment of CH_(4) flux and its influencing drivers in the rice-wheat agroecosystem of the Huai River Basin,China
2
作者 Xiaolan Yu Fangmin Zhang +3 位作者 Yanqiu Fang Xiaohan Zhao Kaidi Zhang Yanyu Lu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第12期4203-4215,共13页
To understand the CH_(4) flux variations and their climatic drivers in the rice-wheat agroecosystem in the Huai River Basin of China,the CH_(4) flux was observed by using open-path eddy covariance at a typical rice-wh... To understand the CH_(4) flux variations and their climatic drivers in the rice-wheat agroecosystem in the Huai River Basin of China,the CH_(4) flux was observed by using open-path eddy covariance at a typical rice-wheat rotation system in Anhui Province,China from November 2019 to October 2021.The variations and their drivers were then analyzed with the Akaike information criterion method.CH_(4) flux showed distinct diurnal variations with single peaks during 9:00-13:00 local time.The highest peak was 2.15μg m^(-2)s^(-1)which occurred at 11:00 in the vegetative growth stage in the rice growing season(RGS).CH_(4) flux also showed significant seasonal variations.The average CH_(4)flux in the vegetative growth stage in the RGS(193.8±74.2 mg m^(-2)d^(-1))was the highest among all growth stages.The annual total CH_(4) flux in the non-rice growing season(3.2 g m^(-2))was relatively small compared to that in the RGS(23.9 g m^(-2)).CH_(4) flux increased significantly with increase in air temperature,soil temperature,and soil water content in both the RGS and the non-RGS,while it decreased significantly with increase in vapor pressure deficit in the RGS.This study provided a comprehensive understanding of the CH_(4) flux and its drivers in the rice-wheat rotation agroecosystem in the Huai River Basin of China.In addition,our findings will be helpful for the validation and adjustment of the CH_(4) models in this region. 展开更多
关键词 CH_(4) flux eddy covariance method rice-wheat rotation agroecosystem Huai River Basin
下载PDF
Crosstalk between androgen signaling and the chemokine receptor CXCR4:a novel strategy to promote myelin regeneration
3
作者 Marianne Bardy-Lagarde Narimène Asbelaoui Abdel Mouman Ghoumari 《Neural Regeneration Research》 SCIE CAS 2025年第9期2581-2582,共2页
Multiple sclerosis(MS)is the most common chronic disease of the central nervous system(CNS)in young adults and represents the first cause of severe handicap,originally non-traumatic(Oh et al.,2018).MS is chara cterize... Multiple sclerosis(MS)is the most common chronic disease of the central nervous system(CNS)in young adults and represents the first cause of severe handicap,originally non-traumatic(Oh et al.,2018).MS is chara cterized by the infiltration of auto reactive lymphocytes specific to myelin through the blood-brain barrier,which results in the appearance of inflammatory demyelinating lesions caused by the death of the central nervous system myelinating cells,oligodendrocytes(Oh et al.,2018).There is a prevalence sexual with a ratio of three times more affected women than men. 展开更多
关键词 MYELIN CXCR4
下载PDF
Sequential Analysis in the Identification of 3rd Order System Tract in the Abidjan Margin
4
作者 Blandine Akissi Egoran N’guessan Donald Ahoure +2 位作者 Fori Yao Paul Assalé Sylvain Mondé Loukou Victor N’da 《Open Journal of Applied Sciences》 2024年第6期1474-1489,共16页
The use of sequential stratigraphy concept, based on well logs, sedimentology, and biostratigraphy, has shed light on the complex mechanisms controlling sedimentary accumulations. Consequently, identifying these mecha... The use of sequential stratigraphy concept, based on well logs, sedimentology, and biostratigraphy, has shed light on the complex mechanisms controlling sedimentary accumulations. Consequently, identifying these mechanisms allows us to predict the hydrocarbon generation potential of source rocks. In the Ivorian offshore sedimentary basin, certain studies have contributed to understanding and characterizing the petroleum system. However, these previous works did not integrate biostratigraphic data to highlight sedimentary facies. This study, conducted on two wells in the Abidjan margin, is crucial as it helps us comprehend the geometry of fossil sediments in relation to sea level variations. It will also aid in reconstructing the basin-filling history and predicting the distribution of rocks capable of trapping oil, determining lowstand systems tracts (reservoir rocks), transgressive systems tracts, and highstand systems tracts (cap rocks). Lithological analysis revealed predominantly clayey sedimentation with sandy layers. Well log data facilitated the delineation of formation boundaries and highlighted reservoirs consisting of sands, sandstones, limestones, and occasionally intercalated shales. Integrating these analysis results with biostratigraphic interpretations based on foraminifera and palynomorphs revealed that the traversed formations were deposited in a transitional environment ranging from Coniacian to Maastrichtian ages. Applying sequential stratigraphy concept from well logging resolved dating issues encountered in microfossil-poor or microfossil-free zones. The results of the Coniacian-Maastrichtian age sequential subdivision were aligned with the chart. 展开更多
关键词 Sequence Stratigraphy systems Tracts Senonian Côte d’Ivoire
下载PDF
RGS4 promotes the progression of gastric cancer through the focal adhesion kinase/phosphatidyl-inositol-3-kinase/protein kinase B pathway and epithelial-mesenchymal transition
5
作者 Peng-Yu Chen Pei-Yao Wang +7 位作者 Bang Liu Yang-Pu Jia Zhao-Xiong Zhang Xin Liu Dao-Han Wang Yong-Jia Yan Wei-Hua Fu Feng Zhu 《World Journal of Gastroenterology》 SCIE CAS 2025年第2期113-127,共15页
BACKGROUND Regulator of G protein signaling(RGS)proteins participate in tumor formation and metastasis by acting on theα-subunit of heterotrimeric G proteins.The speci-fic effect of RGS,particularly RGS4,on the progr... BACKGROUND Regulator of G protein signaling(RGS)proteins participate in tumor formation and metastasis by acting on theα-subunit of heterotrimeric G proteins.The speci-fic effect of RGS,particularly RGS4,on the progression of gastric cancer(GC)is not yet clear.AIM To explore the role and underlying mechanisms of action of RGS4 in GC develop-ment.METHODS The prognostic significance of RGS4 in GC was analyzed using bioinformatics based public databases and verified by immunohistochemistry and quantitative polymerase chain reaction in 90 patients with GC.Function assays were employed to assess the carcinogenic impact of RGS4,and the mechanism of its possible influence was detected by western blot analysis.A nude mouse xenograft model was established to study the effects of RGS4 on GC growth in vitro.RESULTS RGS4 was highly expressed in GC tissues compared with matched adjacent normal tissues.Elevated RGS4 expression was correlated with increased tumor-node-metastasis stage,increased tumor grade as well as poorer overall survival in patients with GC.Cell experiments demonstrated that RGS4 knockdown suppressed GC cell proliferation,migration and invasion.Similarly,xenograft experiments confirmed that RGS4 silencing significantly inhibited tumor growth.Moreover,RGS4 knockdown resulted in reduced phosphorylation levels of focal adhesion kinase,phosphatidyl-inositol-3-kinase,and protein kinase B,decreased vimentin and N-cadherin,and elevated E-cadherin.CONCLUSION High RGS4 expression in GC indicates a worse prognosis and RGS4 is a prognostic marker.RGS4 influences tumor progression via the focal adhesion kinase/phosphatidyl-inositol-3-kinase/protein kinase B pathway and epithelial-mesenchymal transition. 展开更多
关键词 Gastric cancer PROGNOSIS Regulator of G protein signaling 4 Focal adhesion kinase Epithelial-mesenchymal transition
下载PDF
Effects of Shenqi Xiangyi granules in advanced gastric cancer chemotherapy
6
作者 Xiao-Jing Shi Yu Song +4 位作者 Xue-Xue Liang Ting Chen Huang-Yu Hao Xue Han Ya-Nan Chen 《World Journal of Gastrointestinal Oncology》 SCIE 2025年第1期169-175,共7页
BACKGROUND Owing to the absence of specific symptoms in early-stage gastric cancer,most patients are diagnosed at intermediate or advanced stages.As a result,treatment often shifts from surgery to other therapies,with... BACKGROUND Owing to the absence of specific symptoms in early-stage gastric cancer,most patients are diagnosed at intermediate or advanced stages.As a result,treatment often shifts from surgery to other therapies,with chemotherapy and targeted therapies being the primary options for advanced gastric cancer treatment.A total of 116 patients with advanced gastric cancer,admitted from January 2021 to December 2023,were selected and divided into two groups of 58 each using the random number table method.The control group received FOLFOX4 chemothe-rapy(oxaliplatin+calcium+folinate+5-fluorouracil)combined with intravenous sindilizumab.The observation group received the same treatment as the control group,supplemented by oral administration of Senqi Shiyiwei granules.Both groups underwent treatment cycles of 3 weeks,with a minimum of two cycles.The therapeutic efficacy,immune mechanisms,and treatment-related toxicity and side effects were compared between the groups.The objective remission rate in the observation group(55.17%)was higher than that of the control group(36.21%)(P<0.05).After two treatment cycle,CD3+,CD4+,and CD4+/CD8+levels were higher in the observation group compared to the control group,while CD8+,regulatory T cells,and natural killer cells were lower(P<0.05).Additionally,the incidence of leukopenia,nausea,and vomiting was lower in observed group(P<0.05).No significant differences were observed in the incidence of other adverse reactions(P>0.05).CONCLUSION Adjuvant therapy with Shenqixian granules may enhance the efficacy of simudizumab combined with FOLFOX4 chemotherapy in advanced gastric cancer and the immune function by increasing immune cell counts,making it a valuable option in clinical treatment. 展开更多
关键词 Sindilizumab FOLFOX4 chemotherapy Advanced gastric cancer Ginseng Qi Xiangyi granule Clinic treatment
下载PDF
A systematic evaluation of the performance of GPT-4 and PaLM2 to diagnose comorbidities in MIMIC-IV patients
7
作者 Peter Sarvari Zaid Al-fagih +1 位作者 Abdullatif Ghuwel Othman Al-fagih 《Health Care Science》 2024年第1期3-18,共16页
Background:Given the strikingly high diagnostic error rate in hospitals,and the recent development of Large Language Models(LLMs),we set out to measure the diagnostic sensitivity of two popular LLMs:GPT-4 and PaLM2.Sm... Background:Given the strikingly high diagnostic error rate in hospitals,and the recent development of Large Language Models(LLMs),we set out to measure the diagnostic sensitivity of two popular LLMs:GPT-4 and PaLM2.Small-scale studies to evaluate the diagnostic ability of LLMs have shown promising results,with GPT-4 demonstrating high accuracy in diagnosing test cases.However,larger evaluations on real electronic patient data are needed to provide more reliable estimates.Methods:To fill this gap in the literature,we used a deidentified Electronic Health Record(EHR)data set of about 300,000 patients admitted to the Beth Israel Deaconess Medical Center in Boston.This data set contained blood,imaging,microbiology and vital sign information as well as the patients'medical diagnostic codes.Based on the available EHR data,doctors curated a set of diagnoses for each patient,which we will refer to as ground truth diagnoses.We then designed carefully-written prompts to get patient diagnostic predictions from the LLMs and compared this to the ground truth diagnoses in a random sample of 1000 patients.Results:Based on the proportion of correctly predicted ground truth diagnoses,we estimated the diagnostic hit rate of GPT-4 to be 93.9%.PaLM2 achieved 84.7%on the same data set.On these 1000 randomly selected EHRs,GPT-4 correctly identified 1116 unique diagnoses.Conclusion:The results suggest that artificial intelligence(AI)has the potential when working alongside clinicians to reduce cognitive errors which lead to hundreds of thousands of misdiagnoses every year.However,human oversight of AI remains essential:LLMs cannot replace clinicians,especially when it comes to human understanding and empathy.Furthermore,a significant number of challenges in incorporating AI into health care exist,including ethical,liability and regulatory barriers. 展开更多
关键词 GPT-4 diagnostic errors MIMIC-IV clinical decision-making language model patient care health care efficiency
下载PDF
Unlocking the Potential:A Comprehensive Systematic Review of ChatGPT in Natural Language Processing Tasks
8
作者 Ebtesam Ahmad Alomari 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第10期43-85,共43页
As Natural Language Processing(NLP)continues to advance,driven by the emergence of sophisticated large language models such as ChatGPT,there has been a notable growth in research activity.This rapid uptake reflects in... As Natural Language Processing(NLP)continues to advance,driven by the emergence of sophisticated large language models such as ChatGPT,there has been a notable growth in research activity.This rapid uptake reflects increasing interest in the field and induces critical inquiries into ChatGPT’s applicability in the NLP domain.This review paper systematically investigates the role of ChatGPT in diverse NLP tasks,including information extraction,Name Entity Recognition(NER),event extraction,relation extraction,Part of Speech(PoS)tagging,text classification,sentiment analysis,emotion recognition and text annotation.The novelty of this work lies in its comprehensive analysis of the existing literature,addressing a critical gap in understanding ChatGPT’s adaptability,limitations,and optimal application.In this paper,we employed a systematic stepwise approach following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)framework to direct our search process and seek relevant studies.Our review reveals ChatGPT’s significant potential in enhancing various NLP tasks.Its adaptability in information extraction tasks,sentiment analysis,and text classification showcases its ability to comprehend diverse contexts and extract meaningful details.Additionally,ChatGPT’s flexibility in annotation tasks reducesmanual efforts and accelerates the annotation process,making it a valuable asset in NLP development and research.Furthermore,GPT-4 and prompt engineering emerge as a complementary mechanism,empowering users to guide the model and enhance overall accuracy.Despite its promising potential,challenges persist.The performance of ChatGP Tneeds tobe testedusingmore extensivedatasets anddiversedata structures.Subsequently,its limitations in handling domain-specific language and the need for fine-tuning in specific applications highlight the importance of further investigations to address these issues. 展开更多
关键词 Generative AI large languagemodel(LLM) natural language processing(NLP) ChatGPT GPT(generative pretraining transformer) GPT-4 sentiment analysis NER information extraction ANNOTATION text classification
下载PDF
A stringent dual control system overseeing transcription and activity of the Cre recombinase for the liver-specific conditional gene knock-out mouse model 被引量:3
9
作者 Yu Wu Yinghua He +5 位作者 Hongyu Zhang Xinlan Dai Xiaoyu Zhou Jun Gu Guan Wang Jingde Zhu 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2008年第7期431-439,共9页
Liver cancer is one of the most threatening diseases in Chinese population. Just like in other tissues, tumor initiation and development in liver involve multiple steps of genetic and epigenetic alterations with sever... Liver cancer is one of the most threatening diseases in Chinese population. Just like in other tissues, tumor initiation and development in liver involve multiple steps of genetic and epigenetic alterations with several unknown details. However, unlike in other tissues, a tissue specific inducible Cre recombinase system that allows temporal and spatial deletion of a target DNA fragment is still not available for in vivo functional gene annotation in hepatocytes. In our pursuit to establish such a mouse model, we designed a dual inducible Cre transgene system and tested it in cultured cells. By combining a CCAAT/enhancer binding protein β (C/EBP β) promoter derived Tet-off expression system and the estrogen receptor (ER) mediated functional control, we show a desirable profile of both hepatocyte-specificity and regulability of the Cre expression in a series of critical assessments in the cell culture system, which provides confidence in continuation of our ongoing pursuit in mouse. 展开更多
关键词 Cre/loxP TET-OFF hepatocyte-specific DOXYCYCLINE 4-OHT C/EBβ
下载PDF
The Polysystem and the Translation of Children' s Literature
10
作者 狄东睿 《海外英语》 2012年第11X期140-141,共2页
Polysystem Theory was developed in 1970s by Israeli scholar Itamar Even-Zohar,and was well known for its three circumstances.Children' literature,as a special branch of literature,attracts more and more research n... Polysystem Theory was developed in 1970s by Israeli scholar Itamar Even-Zohar,and was well known for its three circumstances.Children' literature,as a special branch of literature,attracts more and more research nowadays.This paper explores the process of translation of Children' s Literature in China under polysystem. 展开更多
关键词 polysystem Children’ s LITERATURE TRANSLATION of C
下载PDF
Soil Aggregate Stability and Aggregate-Associated Carbon Under Different Tillage Systems in the North China Plain 被引量:21
11
作者 DU Zhang-liu REN Tu-sheng +2 位作者 HU Chun-sheng ZHANG Qing-zhong Humberto Blanco-Canqui 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第11期2114-2123,共10页
The inlfuences of tillage systems on soil carbon (C) stocks have been studied extensively, but the distribution of soil C within aggregate fractions is not well understood. The objective of this study was to determi... The inlfuences of tillage systems on soil carbon (C) stocks have been studied extensively, but the distribution of soil C within aggregate fractions is not well understood. The objective of this study was to determine the inlfuences of various tillage systems on soil aggregation and aggregate-associated C under wheat (Triticum aestivum L.) and corn (Zea mays L.) double cropping systems in the North China Plain. The experiment was established in 2001, including four treatments:moldboard plow (MP) with residue (MP+R) and without residue (MP-R), rotary tillage with residue (RT), and no-till with residue (NT). In 2007 soil samples were collected from the 0-5, 5-10, and 10-20 cm depths, and were separated into four aggregate-size classes (〉2 000, 250-2 000, 53-250, and〈53 μm) by wet-sieving method. Aggregate-associated C was determined, and the relationships between total soil C concentration and aggregation-size fractions were examined. The results showed that NT and RT treatments signiifcantly increased the proportion of macroaggregate fractions (〉2 000 and 250-2 000 μm) compared with the MP-R and MP+R treatments. Averaged across all depths, mean weight diameters of aggregates (MWD) in NT and RT were 47 and 20% higher than that in MP+R. The concentration of bulk soil organic C was positively correlated with MWD (r=0.98; P=0.024) and macroaggregate fraction (r=0.96; P=0.036) in the 0-5 cm depth. In the 0-20 cm depth, comparing with MP+R, total C occluded in the〉2 000 μm fraction was increased by 9 and 6%under NT and RT, respectively. We conclude that adoption of conservation tillage system, especially no-till, can increase soil macro-aggregation and total C accumulation in macroaggregates, which may improve soil C sequestration in the intensive agricultural region of the North China Plain. 展开更多
关键词 tillage systems aggregate stability aggregate-associated C
下载PDF
Properties of a New Dental Photocurable Resin based on the Expanding Monomer and Threecomponent Photoinitiator System 被引量:4
12
作者 付静 LIU Wenjia +3 位作者 LIU Xiaoqing Sapna laxmi tuladhar WAN Qianbing 王航 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第2期384-390,共7页
The purpose of this study was to use. a three-component photoinitiation system comprising 1wt% CQ (camphorquinone), 2wt% DMAEMA (2-(dimethylamino) ethyl meth acrylate) and 2wt% ph^2I^+PF6^- (diphenyliodonium h... The purpose of this study was to use. a three-component photoinitiation system comprising 1wt% CQ (camphorquinone), 2wt% DMAEMA (2-(dimethylamino) ethyl meth acrylate) and 2wt% ph^2I^+PF6^- (diphenyliodonium hexafluorophosphate) to initiate the copolymerization of the matrix resins which combine bisphenol-S-bis (3-methacrylate-2-hydroxy propyl) ether (BisS-GMA) with the expanding monomer unsaturated spiro orthoesters 2-methylene-l,4,6-tdspiro[4,4] nonane (MTOSN), for minimizing the volumetric shrinkage that generally occurs during polymerization. It was hypothesized that MTOSN would expand volumetrically during polymerization under the three-component photoinitiator system and further reductions in volumetric shrinkage would be obtained. The performance study which consists of degree of conversion and condition of the ring-opening reactions of MTOSN, volumetric shrinkage and mechanical properties including tensile bond strength, compressive strength and Vicker's hardness were carried out respectively by Fourier transfer infrared, the dilatometer and the universal testing machine. The results supported that the dental composites based on the expanding monomer and three-component photoinitiator system engendered a greater decrease of volumetric shrinkage and better mechanieal properties. 展开更多
关键词 2-methylene-1 4 6-trispiro [4 4] nonane light-curing dental matrix resin volumetric shrinkage mechanical properties
下载PDF
Assimilating Surface Observations in a Four-Dimensional Variational Doppler Radar Data Assimilation System to Improve the Analysis and Forecast of a Squall Line Case 被引量:8
13
作者 Xingchao CHEN Kun ZHAO +2 位作者 Juanzhen SUN Bowen ZHOU Wen-Chau LEE 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第10期1106-1119,共14页
This paper examines how assimilating surface observations can improve the analysis and forecast ability of a four- dimensional Variational Doppler Radar Analysis System (VDRAS). Observed surface temperature and wind... This paper examines how assimilating surface observations can improve the analysis and forecast ability of a four- dimensional Variational Doppler Radar Analysis System (VDRAS). Observed surface temperature and winds are assimilated together with radar radial velocity and reflectivity into a convection-permitting model using the VDRAS four-dimensional variational (4DVAR) data assimilation system. A squall-line case observed during a field campaign is selected to investigate the performance of the technique. A single observation experiment shows that assimilating surface observations can influence the analyzed fields in both the horizontal and vertical directions. The surface-based cold pool, divergence and gust front of the squall line are all strengthened through the assimilation of the single surface observation. Three experiments--assimilating radar data only, assimilating radar data with surface data blended in a mesoscale background, and assimilating both radar and surface observations with a 4DVAR cost function--are conducted to examine the impact of the surface data assimilation. Independent surface and wind profiler observations are used for verification. The result shows that the analysis and forecast are improved when surface observations are assimilated in addition to radar observations. It is also shown that the additional surface data can help improve the analysis and forecast at low levels. Surface and low-level features of the squall line-- including the surface warm inflow, cold pool, gust front, and low-level wind--are much closer to the observations after assimilating the surface data in VDRAS. 展开更多
关键词 VDRAS 4-D data assimilation radar data surface data squall line
下载PDF
Hepatitis B reactivation in patients receiving direct-acting antiviral therapy or interferon-based therapy for hepatitis C:A systematic review and meta-analysis 被引量:8
14
作者 Xian-Wan Jiang Jian-Zhong Ye +1 位作者 Ya-Ting Li Lan-Juan Li 《World Journal of Gastroenterology》 SCIE CAS 2018年第28期3181-3191,共11页
AIM To assess the incidence of hepatitis B virus(HBV) reactivation in patients receiving direct-acting antiviral agent(DAA)-based therapy or interferon(IFN)-based therapy for hepatitis C and the effectiveness of preem... AIM To assess the incidence of hepatitis B virus(HBV) reactivation in patients receiving direct-acting antiviral agent(DAA)-based therapy or interferon(IFN)-based therapy for hepatitis C and the effectiveness of preemptive antiHBV therapy for preventing HBV reactivation.METHODS The Pub Med, MEDLINE and EMBASE databases were searched, and 39 studies that reported HBV reactivation in HBV/hepatitis C virus coinfected patients receiving DAAbased therapy or IFN-based therapy were included. The primary outcome was the rate of HBV reactivation. The secondary outcomes included HBV reactivation-related hepatitis and the effectiveness of preemptive anti-HBV treatment with nucleos(t)ide analogues. The pooled effects were assessed using a random effects model. RESULTS The rate of HBV reactivation was 21.1% in hepatitis Bsurface antigen(HBs Ag)-positive patients receiving DAAbased therapy and 11.9% in those receiving IFN-based therapy. The incidence of hepatitis was lower in HBs Agpositive patients with undetectable HBV DNA compared to patients with detectable HBV DNA receiving DAA therapy(RR = 0.20, 95%CI: 0.06-0.64, P = 0.007). The pooled HBV reactivation rate in patients with previous HBV infection was 0.6% for those receiving DAA-based therapy and 0 for those receiving IFN-based therapy, and none of the patients experienced a hepatitis flare related to HBV reactivation. Preemptive anti-HBV treatment significantly reduced the potential risk of HBV reactivation in HBs Agpositive patients undergoing DAA-based therapy(RR = 0.31, 95%CI: 0.1-0.96, P = 0.042).CONCLUSION The rate of HBV reactivation and hepatitis flare occurrence is higher in HBs Ag-positive patients receiving DAA-based therapy than in those receiving IFN-based therapy, but these events occur less frequently in patients with previous HBV infection. Preemptive anti-HBV treatment is effective in preventing HBV reactivation. 展开更多
关键词 HEPATITIS C HEPATITIS B virus REACTIVATION COINFECTION Direct-acting antiviral agents META-ANALYSIS
下载PDF
Severe adverse events during antiviral therapy in hepatitis C virus cirrhotic patients: A systematic review 被引量:6
15
作者 Simona Bota Ioan Sporea +4 位作者 Roxana Sirli Alina Popescu Adriana Maria Neghinǎ Mirela Dǎnilǎ Mihnea Strǎin 《World Journal of Hepatology》 CAS 2013年第3期120-126,共7页
AIM: To identify severe adverse events (SAEs) leading to treatment discontinuation that occur during antiviral therapy in hepatitis C virus (HCV)-infected cirrhotic patients. METHODS: We identified all the articles pu... AIM: To identify severe adverse events (SAEs) leading to treatment discontinuation that occur during antiviral therapy in hepatitis C virus (HCV)-infected cirrhotic patients. METHODS: We identified all the articles published prior to December 2011 in the PubMed, Medline, Lilacs, Scopus, Ovid, EMBASE, Cochrane and Medscape databases that presented these data in cirrhotic patients. These studies evaluated the rate of SAEs leading to discontinuation of standard care treatment: Pegylated interferon (PegIFN) alpha 2a (135-180 μg/wk) or PegIFN alpha 2b (1 or 1.5 μg/kg per week) and ribavirin (800-1200 mg/d). Patients with genotype 1 + 4 underwent treatment for 48 wk, whereas those with genotypes 2 + 3 were treated for 24 wk.RESULTS: We included 17 papers in this review, comprising of 1133 patients. Treatment was discontinued due to SAEs in 14.5% of the patients. The most common SAEs were: severe thrombocytopenia and/or neutropenia (23.2%), psychiatric disorders (15.5%), decompensation of liver cirrhosis (12.1%) and severe anemia (11.2%). The proportion of patients who needed to discontinue their therapy due to SAEs was significantly higher in patients with Child-Pugh class B and Cvs those with Child-Pugh class A: 22%vs 11.4% (P = 0.003). A similar discontinuation rate was found in cirrhotic patients treated with PegIFN alpha 2a and those treated with PegIFN alpha 2b, in combination with ribavirin: 14.2%vs 13.7% (P = 0.96). The overall sustained virological response rate in cirrhotic patients was 37% (95%CI: 33.5-43.1) but was significantly lower in patients with genotype 1 + 4 than in those with genotype 2 + 3: 20.5% (95%CI: 17.9-24.8) vs 56.5% (95%CI: 51.5-63.2), (P < 0.0001). CONCLUSION: Fourteen point five percent of HCV cirrhotic patients treated with PegIFN and ribavirin needed early discontinuation of therapy due to SAEs, the most common cause being hematological disorders. 展开更多
关键词 Liver CIRRHOSIS HEPATITIS C virus ADVERSE events SUSTAINED virological response
下载PDF
Systematic variation of the sodium/sulfur promoter content on carbon-supported iron catalysts for the Fischer–Tropsch to olefins reaction 被引量:3
16
作者 Martin Oschatz Nynke Krans +1 位作者 Jingxiu Xie Krijn P.de Jong 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2016年第6期985-993,共9页
The Fischer–Tropsch to olefins(FTO) process is a method for the direct conversion of synthesis gas to lower C–Colefins. Carbon-supported iron carbide nanoparticles are attractive catalysts for this reaction.The ca... The Fischer–Tropsch to olefins(FTO) process is a method for the direct conversion of synthesis gas to lower C–Colefins. Carbon-supported iron carbide nanoparticles are attractive catalysts for this reaction.The catalytic activity can be improved and undesired formation of alkanes can be suppressed by the addition of sodium and sulfur as promoters but the influence of their content and ratio remains poorly understood and the promoted catalysts often suffer from rapid deactivation due to particle growth. A series of carbon black-supported iron catalysts with similar iron content and nominal sodium/sulfur loadings of 1–30/0.5–5 wt% with respect to iron are prepared and characterized under FTO conditions at 1and 10 bar syngas pressure to illuminate the influence of the promoter level on the catalytic properties.Iron particles and promoters undergo significant reorganization during FTO operation under industrially relevant conditions. Low sodium content(1–3 wt%) leads to a delay in iron carbide formation. Sodium contents of 15–30 wt% lead to rapid loss of catalytic activity due to the covering of the iron surface with promoters during particle growth under FTO operation. Higher activity and slower loss of activity are observed at low promoter contents(1–3 wt% sodium and 0.5–1 wt% sulfur) but a minimum amount of alkali is required to effectively suppress methane and C–Cparaffin formation. A reference catalyst support(carbide-derived carbon aerogel) shows that the optimum promoter level depends on iron particle size and support pore structure. 展开更多
关键词 Fischer–Tropsch to olefins synthesis C2–C4 olefins Iron catalysts Promoters Carbon supports
下载PDF
Effect of high-voltage discharge non-thermal plasma on g-C_3N_4 in a plasma-photocatalyst system 被引量:3
17
作者 Xiaoping Wang Yixia Chen +2 位作者 Min Fu Zihan Chen Qiulin Huang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第10期1672-1682,共11页
The synergistic effect of high voltage discharge non‐thermal plasma(NTP)and photocatalysts on contaminant removal has repeatedly confirmed by plenty of researches.Most previous plasma‐photocatalyst synergistic syste... The synergistic effect of high voltage discharge non‐thermal plasma(NTP)and photocatalysts on contaminant removal has repeatedly confirmed by plenty of researches.Most previous plasma‐photocatalyst synergistic systems focused on the utilization of the ultraviolet light but ignored the visible light generated by high voltage discharge.Graphitic carbon nitride(g‐C3N4),a metal‐free semiconductor that exhibits high chemical stability,can utilize both the ultraviolet and visible light from high voltage discharge.However,the synergistic system of NTP and g‐C3N4 has been researched little.In this paper,the effect of NTP generated by dielectric barrier discharge(DBD)on g‐C3N4 is studied by comparing the photocatalytic activities,the surface physical structure and the surface chemical characteristics of pristine and plasma treated g‐C3N4.Experimental results indicate that the DBD plasma can change the physical structure and the chemical characteristics and to further affect the photocatalytic activity of g‐C3N4.The effect of NTP on g‐C3N4 is associated with the discharge intensity and the discharge time.For a long time scale,the effect of NTP on g‐C3N4 photocatalysts presents a periodic change trend. 展开更多
关键词 g‐C3N4 Non‐thermal plasma Photocatalytic activity Physical structure Chemical characteristic
下载PDF
Nuclear Safety Functions of ITER Gas Injection System Instrumentation and Control and the Concept Design 被引量:1
18
作者 杨愚 S.MARUYAMA +6 位作者 A.FOSSEN F.VILLERS G.KISS 张博 李波 江涛 黄向玫 《Plasma Science and Technology》 SCIE EI CAS CSCD 2016年第8期875-878,共4页
The ITER Gas Injection System(GIS) plays an important role on fueling, wall conditioning and distribution for plasma operation. Besides that, to support the safety function of ITER, GIS needs to implement three nucl... The ITER Gas Injection System(GIS) plays an important role on fueling, wall conditioning and distribution for plasma operation. Besides that, to support the safety function of ITER, GIS needs to implement three nuclear safety Instrumentation and Control(I&C) functions.In this paper, these three functions are introduced with the emphasis on their latest safety classifications. The nuclear I&C design concept is briefly discussed at the end. 展开更多
关键词 ITER GIS I&C nuclear safety
下载PDF
Expression of CD80/CD86 and CTLA-4 mRNA in Peripheral Blood Mononuclear Cells of the Patients with Systemic Lupus Erythematosus 被引量:1
19
作者 刘文斌 李家文 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2004年第3期247-249,共3页
Summary: The role of CD80/CD86 and CTLA-4 in the pathogenesis of systemic lupus erythematosus and their clinical significance was investigated. By using RT-PCR technique, the expression of CD80/CD86 and CTLA-4 mRNA in... Summary: The role of CD80/CD86 and CTLA-4 in the pathogenesis of systemic lupus erythematosus and their clinical significance was investigated. By using RT-PCR technique, the expression of CD80/CD86 and CTLA-4 mRNA in peripheral blood mononuclear cells (PBMC) were semiquantitatively detected in 32 patients with active SLE. The results showed that the percentage of positive CD86 expression in active SLE was increased significantly as compared with normal controls (90.63 % vs 60.00 %, P<0.01). The mean level of CD86 mRNA expression in active SLE group was markedly higher than in the normal controls (0.6410+0.0174 vs 0.4510+0.0402, P<0.001). Compared with normal controls, the percentage of positive CTLA-4 expression and the mean level of CTLA-4 mRNA expression in active SLE group were both increased significantly (both P<0.01). There was no statistical differences in positive rate of CD80 and the average level of CD80 mRNA between the two groups (both P>0.05). It was concluded that the aberrant expression of CD86 and CTLA-4 might play an important role in the activity and development of SLE. 展开更多
关键词 lupus erythematosus systemic ANTIGEN CD80 CD86 CTLA-4
下载PDF
Experimental method to explore the adaptation degree of type-Ⅱand all-solid-state Z-scheme heterojunction structures in the same degradation system 被引量:2
20
作者 Zheao Huang Shuo Zhao Ying Yu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第10期1522-1534,共13页
TiO2 nanoparticles were prepared using the hydrothermal method and modified with CgN to syn-thesize a Type-Ⅱheterojunction semiconductor photocatalyst,TiO2-C;Na.In addition,a carbon layerwas coated onto the TiO2 nano... TiO2 nanoparticles were prepared using the hydrothermal method and modified with CgN to syn-thesize a Type-Ⅱheterojunction semiconductor photocatalyst,TiO2-C;Na.In addition,a carbon layerwas coated onto the TiO2 nanoparticles and the obtained material was uniformly covered on thesurface of CaNa to form an all-solid-state Z-scheme semiconductor photocatalyst,TiO2-C-C3N4,Through characterization by XRD,XPS,SEM,TEM,BET,photoelectrochemical experiments,UV-visible diffuse reflection,and PL spectroscopy,the charge transfer mechanism and band gappositions for the composite photocatalysts were analyzed.The Type-Ⅱand all-solid-state Z-schemeheterojunction structures were compared.By combining microscopic internal mechanisms withmacroscopic experimental phenomena,the relationship between performance and structure wasverified.Experimental methods were used to explore the adaptation degree of different photocata-lytic mechanisms using the same degradation system.This study highlights effective photocatalystdesign to meet the requirements for specific degradation conditions. 展开更多
关键词 TiO2-C3N4 TiO2-C-C3N4 Photodegradation Type-Ⅱheterojunction semiconductor Z-scheme heterojunction structure SEMICONDUCTOR
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部