期刊文献+
共找到475,997篇文章
< 1 2 250 >
每页显示 20 50 100
Effectiveness of Histopathological Examination of Ultrasound-guided Puncture Biopsy Samples for Diagnosis of Extrapulmonary Tuberculosis
1
作者 GU Wen Fei SHI Xia +5 位作者 MA Xin YU Jun Lei XU Jin Chuan QIAN Cheng Cheng HU Zhi Dong ZHANG Hui 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第2期170-177,共8页
Objective To evaluate the diagnostic value of histopathological examination of ultrasound-guided puncture biopsy samples in extrapulmonary tuberculosis(EPTB).Methods This study was conducted at the Shanghai Public Hea... Objective To evaluate the diagnostic value of histopathological examination of ultrasound-guided puncture biopsy samples in extrapulmonary tuberculosis(EPTB).Methods This study was conducted at the Shanghai Public Health Clinical Center.A total of 115patients underwent ultrasound-guided puncture biopsy,followed by MGIT 960 culture(culture),smear,Gene Xpert MTB/RIF(Xpert),and histopathological examination.These assays were performed to evaluate their effectiveness in diagnosing EPTB in comparison to two different diagnostic criteria:liquid culture and composite reference standard(CRS).Results When CRS was used as the reference standard,the sensitivity and specificity of culture,smear,Xpert,and histopathological examination were(44.83%,89.29%),(51.72%,89.29%),(70.11%,96.43%),and(85.06%,82.14%),respectively.Based on liquid culture tests,the sensitivity and specificity of smear,Xpert,and pathological examination were(66.67%,72.60%),(83.33%,63.01%),and(92.86%,45.21%),respectively.Histopathological examination showed the highest sensitivity but lowest specificity.Further,we found that the combination of Xpert and histopathological examination showed a sensitivity of 90.80%and a specificity of 89.29%.Conclusion Ultrasound-guided puncture sampling is safe and effective for the diagnosis of EPTB.Compared with culture,smear,and Xpert,histopathological examination showed higher sensitivity but lower specificity.The combination of histopathology with Xpert showed the best performance characteristics. 展开更多
关键词 Extrapulmonary tuberculosis DIAGNOSIS BIOPSY Histopathological examination Puncture samples
下载PDF
Colorectal cancer’s burden attributable to a diet high in processed meat in the Belt and Road Initiative countries
2
作者 Gu Liu Chang-Min Li +5 位作者 Fei Xie Qi-Lai Li Liang-Yan Liao Wen-Jun Jiang Xiao-Pan Li Guan-Ming Lu 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第1期182-196,共15页
BACKGROUND Colorectal cancer(CRC)plays a significant role in morbidity,mortality,and economic cost in the Belt and Road Initiative(“B and R”)countries.In addition,these countries have a substantial consumption of pr... BACKGROUND Colorectal cancer(CRC)plays a significant role in morbidity,mortality,and economic cost in the Belt and Road Initiative(“B and R”)countries.In addition,these countries have a substantial consumption of processed meat.However,the burden and trend of CRC in relation to the consumption of a diet high in processed meat(DHPM-CRC)in these“B and R”countries remain unknown.AIM To analyze the burden and trend of DHPM-CRC in the“B and R”countries from 1990 to 2019.METHODS We used the 2019 Global Burden of Disease Study to collate information regarding the burden of DHPM-CRC.Numbers and age-standardized rates(ASRs)of deaths along with the disability-adjusted life years(DALYs)were determined among the“B and R”countries in 1990 and 2019.Using joinpoint regression analysis,the average annual percent change(AAPC)was used to analyze the temporal trends of age-standardized DALYs rate(ASDALR)from 1990 to 2019 and in the final decade(2010–2019).RESULTS We found geographical differences in the burden of DHPM-CRC among“B and R”countries,with the three highest-ranking countries being the Russian Federation,China,and Ukraine in 1990,and China,the Russian Federation,and Poland in 2019.The burden of DHPM-CRC generally increased in most member countries from 1990 to 2019(all P<0.05).The absolute number of deaths and DALYs in DHPM-CRC were 3151.15[95%uncertainty interval(UI)665.74-5696.64]and 83249.31(95%UI 15628.64-151956.31)in China in 2019.However,the number of deaths(2627.57-2528.51)and DALYs(65867.39-55378.65)for DHPM-CRC in the Russian Federation has declined.The fastest increase in ASDALR for DHPM-CRC was observed in Vietnam,Southeast Asia,with an AAPC value of 3.90%[95%confidence interval(CI):3.63%-4.16%],whereas the fastest decline was observed in Kyrgyzstan,Central Asia,with an AAPC value of-2.05%(95%CI:-2.37%to-1.73%).A substantial upward trend in ASR of mortality,years lived with disability,years of life lost,and DALYs from DHPM-CRC changes in 1990-2019 and the final decade(2010-2019)for most Maritime Silk Route members in East Asia,South Asia,Southeast Asia,North Africa,and the Middle East,as well as Central Europe,while those of the most Land Silk Route members in Central Asia and Eastern Europe have decreased markedly(all P<0.05).The ASDALR for DHPM-CRC increased more in males than in females(all P<0.05).For those aged 50-74 years,the ASDALR for DHPM-CRC in 40 members exhibited an increasing trend,except for 20 members,including 7 members in Central Asia,Maldives,and 12 high or high-middle social development index(SDI)members in other regions(all P<0.05).CONCLUSION The burden of DHPM-CRC varies substantially across“B and R”countries and threatens public health.Relevant evidence-based policies and interventions tailored to the different trends of countries in SDIs or Silk Routes should be adopted to reduce the future burden of CRC in“B and R”countries via extensive collaboration. 展开更多
关键词 Belt and Road Initiative countries Colorectal cancer Burden of disease Dietary risk factors processed meat Disability-adjusted life years Trend analysis
下载PDF
Microstructure evolution and mechanical properties of hot deformed Mg9Al1Zn samples containing a friction stir processed zone 被引量:2
3
作者 E.Cerri D.Knez +1 位作者 T.Rimoldi M.T.Di Giovanni 《Journal of Magnesium and Alloys》 SCIE EI CAS 2017年第4期388-403,共16页
During the last decade,FSP of magnesium alloys has become more popular due to the potential microstructure refinement of their eutectic phases,and interest has increased around the AZ1 that is one of the most commerci... During the last decade,FSP of magnesium alloys has become more popular due to the potential microstructure refinement of their eutectic phases,and interest has increased around the AZ1 that is one of the most commercially used magnesium alloys.In this work,high pressure die cast AZ91 plates were tensile tested at high temperatures after friction stir processing(FSP),with the stirred region in the middle of the gauge length.Samples deformed at 350℃ revealed an increment of ductility that was doubled as compared to those deformed at 300℃ and a strengthening of the nugget was measured by Vickers microhardness(HV).The correlation of HV average values to local grain size confirmed the validity of the Hall–Petch type equation where stress is replaced by hardness.X-rays diffraction and electrical conductivity highlighted the potential increment of solute atoms in solid solution during FSP.Scanning Electron Microscopy(SEM)and Transmission Electron Microscopy(TEM)investigations performed on as-FSPed and hot deformed samples determined MgAlZn and AlMn particles type evolution through statistical analysis that supported mechanical properties and the strengthening mechanisms. 展开更多
关键词 AZ91 Friction stir processing Mechanical properties Microstructure SEM TEM
下载PDF
Green‑Solvent Processed Blade‑Coating Organic Solar Cells with an Efficiency Approaching 19%Enabled by Alkyl‑Tailored Acceptors 被引量:1
4
作者 Hairui Bai Ruijie Ma +23 位作者 Wenyan Su Top Archie Dela Pea Tengfei Li Lingxiao Tang Jie Yang Bin Hu Yilin Wang Zhaozhao Bi Yueling Su Qi Wei Qiang Wu Yuwei Duan Yuxiang Li Jiaying Wu Zicheng Ding Xunfan Liao Yinjuan Huang Chao Gao Guanghao Lu Mingjie Li Weiguo Zhu Gang Li Qunping Fan Wei Ma 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第12期449-462,共14页
Power-conversion-efficiencies(PCEs)of organic solar cells(OSCs)in laboratory,normally processed by spin-coating technology with toxic halogenated solvents,have reached over 19%.However,there is usually a marked PCE dr... Power-conversion-efficiencies(PCEs)of organic solar cells(OSCs)in laboratory,normally processed by spin-coating technology with toxic halogenated solvents,have reached over 19%.However,there is usually a marked PCE drop when the bladecoating and/or green-solvents toward large-scale printing are used instead,which hampers the practical development of OSCs.Here,a new series of N-alkyl-tailored small molecule acceptors named YR-SeNF with a same molecular main backbone are developed by combining selenium-fused central-core and naphthalene-fused endgroup.Thanks to the N-alkyl engineering,NIR-absorbing YR-SeNF series show different crystallinity,packing patterns,and miscibility with polymeric donor.The studies exhibit that the molecular packing,crystallinity,and vertical distribution of active layer morphologies are well optimized by introducing newly designed guest acceptor associated with tailored N-alkyl chains,providing the improved charge transfer dynamics and stability for the PM6:L8-BO:YRSeNF-based OSCs.As a result,a record-high PCE approaching 19%is achieved in the blade-coating OSCs fabricated from a greensolvent o-xylene with high-boiling point.Notably,ternary OSCs offer robust operating stability under maximum-power-point tracking and well-keep>80%of the initial PCEs for even over 400 h.Our alkyl-tailored guest acceptor strategy provides a unique approach to develop green-solvent and blade-coating processed high-efficiency and operating stable OSCs,which paves a way for industrial development. 展开更多
关键词 Alkyl-tailored guest acceptors Blade-coating Green solvent processing Stability Organic solar cells
下载PDF
Microscale crack propagation in shale samples using focused ion beam scanning electron microscopy and three-dimensional numerical modeling 被引量:1
5
作者 Xin Liu Si-Wei Meng +3 位作者 Zheng-Zhao Liang Chun'an Tang Jia-Ping Tao Ji-Zhou Tang 《Petroleum Science》 SCIE EI CAS CSCD 2023年第3期1488-1512,共25页
Reliable prediction of the shale fracturing process is a challenging problem in exploiting deep shale oil and gas resources.Complex fracture networks need to be artificially created to employ deep shale oil and gas re... Reliable prediction of the shale fracturing process is a challenging problem in exploiting deep shale oil and gas resources.Complex fracture networks need to be artificially created to employ deep shale oil and gas reserves.Randomly distributed minerals and heterogeneities in shales significantly affect mechanical properties and fracturing behaviors in oil and gas exploitation.Describing the actual microstructure and associated heterogeneities in shales constitutes a significant challenge.The RFPA3D(rock failure process analysis parallel computing program)-based modeling approach is a promising numerical technique due to its unique capability to simulate the fracturing behavior of rocks.To improve traditional numerical technology and study crack propagation in shale on the microscopic scale,a combination of high-precision internal structure detection technology with the RFPA^(3D) numerical simulation method was developed to construct a real mineral structure-based modeling method.First,an improved digital image processing technique was developed to incorporate actual shale microstructures(focused ion beam scanning electron microscopy was used to capture shale microstructure images that reflect the distri-butions of different minerals)into the numerical model.Second,the effect of mineral inhomogeneity was considered by integrating the mineral statistical model obtained from the mineral nanoindentation experiments into the numerical model.By simulating a shale numerical model in which pyrite particles are wrapped by organic matter,the effects of shale microstructure and applied stress state on microcrack behavior and mechanical properties were investigated and analyzed.In this study,the effect of pyrite particles on fracture propagation was systematically analyzed and summarized for the first time.The results indicate that the distribution of minerals and initial defects dominated the fracture evolution and the failure mode.Cracks are generally initiated and propagated along the boundaries of hard mineral particles such as pyrite or in soft minerals such as organic matter.Locations with collections of hard minerals are more likely to produce complex fractures.This study provides a valuable method for un-derstanding the microfracture behavior of shales. 展开更多
关键词 FIB-SEM Digital imageprocessing Realistic microstructure 3D digital shale fracture process simulation PYRITE
下载PDF
Metal Corrosion Rate Prediction of Small Samples Using an Ensemble Technique
6
作者 Yang Yang Pengfei Zheng +3 位作者 Fanru Zeng Peng Xin Guoxi He Kexi Liao 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第1期267-291,共25页
Accurate prediction of the internal corrosion rates of oil and gas pipelines could be an effective way to prevent pipeline leaks.In this study,a proposed framework for predicting corrosion rates under a small sample o... Accurate prediction of the internal corrosion rates of oil and gas pipelines could be an effective way to prevent pipeline leaks.In this study,a proposed framework for predicting corrosion rates under a small sample of metal corrosion data in the laboratory was developed to provide a new perspective on how to solve the problem of pipeline corrosion under the condition of insufficient real samples.This approach employed the bagging algorithm to construct a strong learner by integrating several KNN learners.A total of 99 data were collected and split into training and test set with a 9:1 ratio.The training set was used to obtain the best hyperparameters by 10-fold cross-validation and grid search,and the test set was used to determine the performance of the model.The results showed that theMean Absolute Error(MAE)of this framework is 28.06%of the traditional model and outperforms other ensemblemethods.Therefore,the proposed framework is suitable formetal corrosion prediction under small sample conditions. 展开更多
关键词 Oil pipeline BAGGING KNN ensemble learning small sample size
下载PDF
Yarn Quality Prediction for Small Samples Based on AdaBoost Algorithm
7
作者 刘智玉 陈南梁 汪军 《Journal of Donghua University(English Edition)》 CAS 2023年第3期261-266,共6页
In order to solve the problems of weak prediction stability and generalization ability of a neural network algorithm model in the yarn quality prediction research for small samples,a prediction model based on an AdaBo... In order to solve the problems of weak prediction stability and generalization ability of a neural network algorithm model in the yarn quality prediction research for small samples,a prediction model based on an AdaBoost algorithm(AdaBoost model) was established.A prediction model based on a linear regression algorithm(LR model) and a prediction model based on a multi-layer perceptron neural network algorithm(MLP model) were established for comparison.The prediction experiments of the yarn evenness and the yarn strength were implemented.Determination coefficients and prediction errors were used to evaluate the prediction accuracy of these models,and the K-fold cross validation was used to evaluate the generalization ability of these models.In the prediction experiments,the determination coefficient of the yarn evenness prediction result of the AdaBoost model is 76% and 87% higher than that of the LR model and the MLP model,respectively.The determination coefficient of the yarn strength prediction result of the AdaBoost model is slightly higher than that of the other two models.Considering that the yarn evenness dataset has a weaker linear relationship with the cotton dataset than that of the yarn strength dataset in this paper,the AdaBoost model has the best adaptability for the nonlinear dataset among the three models.In addition,the AdaBoost model shows generally better results in the cross-validation experiments and the series of prediction experiments at eight different training set sample sizes.It is proved that the AdaBoost model not only has good prediction accuracy but also has good prediction stability and generalization ability for small samples. 展开更多
关键词 stability and generalization ability for small samples.Key words:yarn quality prediction AdaBoost algorithm small sample generalization ability
下载PDF
Development of a loop‑mediated isothermal amplification assay for detection of Austropeplea tomentosa from environmental water samples
8
作者 Lily Tran Vignesh A.Rathinasamy Travis Beddoe 《Animal Diseases》 2023年第1期35-48,共14页
Lymnaeid snails are key intermediate hosts for the development and survival of Fasciola spp.,the causative agent of Fascioliasis which are economically important parasites infecting humans and livestock globally.The c... Lymnaeid snails are key intermediate hosts for the development and survival of Fasciola spp.,the causative agent of Fascioliasis which are economically important parasites infecting humans and livestock globally.The current control method for treating Fascioliasis is heavily reliant on anthelmintic drugs,particularly Triclabendazole(TCBZ)which has resulted in drug-resistant parasites and poses significant risk as there are no long-term efficacious alternatives available.Sustainable control measures at the farm level could include both parasite and snail control will play an important role in Fasciola spp.control and reduce the reliance on anthelmintic drugs.Implementation of such sustainable control measures requires effective identification of snails on the property however Lymnaeid snails are small and difficult to physically locate.Snail identification using an environmental DNA approach is a recent approach in which physically locating snails are not required.Austropeplea tomentosa,is the primary intermediate snail host for F.hepatica transmission in South-East Australia and we present an in-field loop-mediated isothermal amplification and water filtering method for the detection of A.tomentosa eDNA from water samples to improve current surveillance methods.This methodology is highly sensitive with a detection limit of 5×10^(−6)ng/μL,detected in<20 minutes,with cumulative sample preparation and amplification time under 1 hour.This proposed workflow could assist in monitoring areas to determine the risk of Fascioliasis infection and implement strategies to manage snail populations to ultimately reduce the risk of infection for humans and livestock. 展开更多
关键词 Fasciola spp. SNAIL Molecular detection DNA diagnostics LAMP Environmental sampling EDNA
下载PDF
Geochemical Orientation Study of Stream Sediment Samples in the Southern Part of Nuggihalli Schist Belt: Ore Mineral Phases and Their Implications on the Bedrock Potential for Ores
9
作者 B. G. Dayanand S. Santhosh B. C. Prabhakar 《Open Journal of Geology》 2023年第8期806-827,共22页
Stream sediment sampling is a significant tool in geochemical exploration. The stream sediment composition reflects the bedrock geology, overburden cover, and metalliferous mineralization. This research article focuse... Stream sediment sampling is a significant tool in geochemical exploration. The stream sediment composition reflects the bedrock geology, overburden cover, and metalliferous mineralization. This research article focuses on assessing selected trace element concentrations in stream sediments and interpreting their inter-element relationships using multivariate statistical methods. Tagadur Ranganathaswamy Gudda and its surroundings in the Nuggihalli schist belt of southern India have been investigated in the present work. The geology of the study area is complex, with a diverse range of litho units and evidence of strong structural deformation. The area is known for its mineralization potential for chromite, vanadiferous titanomagnetite, and sulfides. The topography of the region is characterized by an undulating terrain with a radial drainage pattern. Most part of the schist belt is soil covered except the Tagadur Ranganathaswamy Gudda area. For this study, a discrete stream sediment sampling method was adopted to collect the samples. Stream sediment samples were collected using a discrete sampling method and analyzed for trace elements using an ICP-AES spectrophotometer: Fe, Cr, Ti, V, Cu, Ni, Zn, Pb, Mn, Cd, and As have been analyzed. The analytical data were statistically treated using the SPSS software, including descriptive statistics, normalization of data using natural log transformation, and factor analysis with varimax rotation. The transformed data showed a log-normal distribution, indicating the presence of geochemical anomalies. The results of the study provide valuable insights into the geochemical processes and mineralization potential of the study area. The statistical analysis helps in understanding the inter-element relationships and identifying element groups and their implications on bedrock potential mineralization. Additionally, spatial analysis using inverse distance weighting interpolation provides information about the distribution of geochemical parameters across the study area. Overall, this research contributes to the understanding of stream sediment geochemistry and its application in mineral exploration. The findings have implications for future exploration efforts and can aid in the identification of potential ore deposits in the Nuggihalli schist belt and similar geological settings. 展开更多
关键词 Geochemical Exploration Stream Sediment Sediment Sampling Heavy Mineral Concentrates Nuggihalli Schist Belt Dharwar Craton
下载PDF
Goodness-of-Fit Test for Non-Stationary and Strongly Dependent Samples
10
作者 Carolina Crisci Gonzalo Perera Lia Sampognaro 《Advances in Pure Mathematics》 2023年第5期226-236,共11页
In this article we improve a goodness-of-fit test, of the Kolmogorov-Smirnov type, for equally distributed- but not stationary-strongly dependent data. The test is based on the asymptotic behavior of the empirical pro... In this article we improve a goodness-of-fit test, of the Kolmogorov-Smirnov type, for equally distributed- but not stationary-strongly dependent data. The test is based on the asymptotic behavior of the empirical process, which is much more complex than in the classical case. Applications to simulated data and discussion of the obtained results are provided. This is, to the best of our knowledge, the first result providing a general goodness of fit test for non-weakly dependent data. 展开更多
关键词 Kolmogorov-Smirnov Test Strongly Dependent Data Asymptotic Behavior of Empirical Processes
下载PDF
Multi-component quantitative and feed-forward neural network for pattern classification of raw and wine-processed Corni Fructus
11
作者 Yu Liu Ying-Fang Cui +3 位作者 Dan-Dan Shi Shu-Li Man Xia Li Wen-Yuan Gao 《Traditional Medicine Research》 2023年第1期12-19,共8页
Background:To promote the quality evaluation,clarify the processing mechanism and distinguish origins of Corni Fructus(cornus)from different regions.Methods:This study developed a high performance liquid chromatograph... Background:To promote the quality evaluation,clarify the processing mechanism and distinguish origins of Corni Fructus(cornus)from different regions.Methods:This study developed a high performance liquid chromatography method for simultaneous determination of 5-hydroxymethylfurfural,2 phenolic acids and 4 iridoid glycosides and the reference fingerprint of cornus from different regions.In addition,the feedforward neural network model provided a pattern classification of sample regions.Results:The content of morroniside and loganin were the highest in all raw cornus samples ranging from 9.45μg/mg to 16.3μg/mg and 6.64μg/mg to 13.7μg/mg,respectively.The level of sweroside in raw cornus from Henan(0.83μg/mg^(-1).39μg/mg)and Zhejiang(0.64μg/mg^(-1).17μg/mg)were greater than other origins.After wine-processing,the glucose or fructose were dehydrated to increase the levels of 5-hydroxymethylfurfural.The C-4 position of-COOCH3 of hot-sensitive iridoid glycosides was hydrolyzed to generate-COOH as stable components.Polyphenol derivatives may be degraded to increase the content of phenolic acid.Subsequently,an excellent feedforward neural network model for identification of raw cornus and wine-prepared cornus was established which could distinguish the sample origins.Conclusion:This work provided a trustworthy method to evaluate the quality and distinguish the sources of cornus.Meanwhile,the clear processing mechanism provided a scientific foundation for controlling the cornus quality during wine-processing. 展开更多
关键词 Cornus officinalis Sieb.et Zucc. quality evaluation FINGERPRINTS processing mechanism feedforward neural network
下载PDF
Influence of tool rotational speed on mechanical and corrosion behaviour of friction stir processed AZ31/Al_(2)O_(3)nanocomposite
12
作者 Ashish Kumar V.P.Singh +5 位作者 Akhileshwar Nirala R.C.Singh Rajiv Chaudhary Abdel-Hamid I.Mourad B.K.Sahoo Deepak Kumar 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第7期2585-2599,共15页
Nano-sized reinforcements improved the mechanical characteristics efficiently by promoting more implicit particle hardening mechanisms compared to micron-sized reinforcements.Nano-sized particles lessen the critical p... Nano-sized reinforcements improved the mechanical characteristics efficiently by promoting more implicit particle hardening mechanisms compared to micron-sized reinforcements.Nano-sized particles lessen the critical particle solidification velocity for swamp and thus offers better dispersal.In the present investigation,the friction stir processing(FSP)is utilized to produce AZ31/Al_(2)O_(3)nanocomposites at various tool rotation speeds(i.e.,900,1200,and 1500 rpm)with an optimized 1.5%volume alumina(Al_(2)O_(3))reinforcement ratio.The mechanical and corrosion behavior of AZ31/Al_(2)O_(3)-developed nanocomposites was investigated and compared with that of the AZ31 base alloy.The AZ31 alloy experienced a comprehensive dynamic recrystallization during FSP,causing substantial grain refinement.Grain-size strengthening is the primary factor contributed to the enhancement in the strength of the fabricated nanocomposite.Tensile strength and yield strength values were lower than those for the base metal matrix,although an upward trend in both values has been observed with an increase in tool rotation speed.An 19.72%increase in hardness along with superior corrosion resistance was achieved compared to the base alloy at a tool rotational speed of 1500 rpm.The corrosion currents(Jcorr)of all samples dropped with increase in the rotational speed,in contrast to the corrosion potentials(Ecorr),which increased.The values of Jcorr of AZ31/Al_(2)O_(3)were 42.3%,56.8%,and 65.5%lower than those of AZ31 alloy at the chosen rotating speeds of 900,1200,and 1500 rpm,respectively.The corrosion behavior of friction stir processed nanocomposites have been addressed in this manuscript which has not been given sufficient attention in the existing literature.Further,this work offers an effective choice for the quality assurance of the FSP process of AZ31/Al_(2)O_(3)nanocomposites.The obtained results are relevant to the development of lightweight automobile and aerospace structures and components. 展开更多
关键词 Friction stir processing AZ31 alloy Al_(2)O_(3) NANOCOMPOSITE Mechanical properties Corrosion resistance
下载PDF
Liver Transplantation Outcomes of HBV-,HCV-,and Alcohol-induced Hepatocellular Carcinoma in the United States:Analysis of National Inpatient Samples
13
作者 Si-si ZHANG Jin-feng ZHANG +4 位作者 Jing-qiong WANG Jing TANG Zi-long WU Jing HUANG Jun XUE 《Current Medical Science》 SCIE CAS 2023年第3期520-525,共6页
Objective Liver transplantation is a current treatment option for hepatocellular carcinoma(HCC).The United States National Inpatient Sample database was utilized to identify risk factors that influence the outcome of ... Objective Liver transplantation is a current treatment option for hepatocellular carcinoma(HCC).The United States National Inpatient Sample database was utilized to identify risk factors that influence the outcome of liver transplantation,including locoregional recurrence,distant metastasis,and in-hospital mortality,in HCC patients with concurrent hepatitis B infection,hepatitis C infection,or alcoholic cirrhosis.Methods This retrospective cohort study included HCC patients(n=2391)from the National Inpatient Sample database who underwent liver transplantation and were diagnosed with hepatitis B or C virus infection,co-infection with hepatitis B and C,or alcoholic cirrhosis of the liver between 2005 and 2014.Associations between HCC etiology and post-transplant outcomes were examined with multivariate analysis models.Results Liver cirrhosis was due to alcohol in 10.5%of patients,hepatitis B in 6.6%,hepatitis C in 10.8%,and combined hepatitis B and C infection in 24.3%.Distant metastasis was found in 16.7%of patients infected with hepatitis B and 9%of hepatitis C patients.Local recurrence of HCC was significantly more likely to occur in patients with hepatitis B than in those with alcohol-induced disease.Conclusion After liver transplantation,patients with hepatitis B infection have a higher risk of local recurrence and distant metastasis.Postoperative care and patient tracking are essential for liver transplant patients with hepatitis B infection. 展开更多
关键词 alcoholic hepatitis hepatocellular carcinoma liver cirrhosis National Inpatient Sample(NIS)transplantation viral hepatitis
下载PDF
Comparative metabolomics analysis in the clean label ingredient of NFC spine grape juice processed by mild heating vs high pressure processing
14
作者 Shini Yang Lu Mi +4 位作者 Kewen Wang Xue Wang Jihong Wu Meijun Wang Zhenzhen Xu 《Food Innovation and Advances》 2023年第2期95-105,共11页
Not from concentrate(NFC)fruit juice is the crucial clean label ingredient for new-style tea-making due to its pleasant color and fresh aroma.Here,we compared the effects of mild heating(MH)and high pressure processin... Not from concentrate(NFC)fruit juice is the crucial clean label ingredient for new-style tea-making due to its pleasant color and fresh aroma.Here,we compared the effects of mild heating(MH)and high pressure processing(HPP)on physicochemical characters and phytochemicals in NFC spine grape juice based on metabolomics analysis.Similar compound profiles were observed between HPP-treated and fresh juices.The richer phytochemical compounds comprised malvidin-3-O-glucoside,malvidin-3,5-di-O-glucoside,quercetin-3-O-rhamnoside,quercetin-3-Oglucuronide,catechin,caffeic acid,ferulic acid,procyanidin B1,procyanidin B2 were obtained after MH treatment.Nine marker phenolics and two marker tripeptides(i.e.,Glu-Val-Phe and Leu-Leu-Tyr)were identified to differentiate MH from HPP treatment,of which higher contents occurred in the MH group.Storage time experiments showed that the Glu-Val-Phe could serve as potential markers for monitoring storage of spine grape juice.These results provide new insights into the effects of processing on individual phytochemical changes and the guide for commercial application of production of spine grape NFC juice. 展开更多
关键词 NFC high processing
下载PDF
主题方面共享的领域主题层次模型
15
作者 万常选 张奕韬 +3 位作者 刘德喜 刘喜平 廖国琼 万齐智 《软件学报》 EI CSCD 2024年第4期1790-1818,共29页
层次主题模型是构建主题层次的重要工具.现有的层次主题模型大多通过在主题模型中引入nCRP构造方法,为文档主题提供树形结构的先验分布,但无法生成具有明确领域涵义的主题层次结构,即领域主题层次.同时,领域主题不仅存在层次关系,而且... 层次主题模型是构建主题层次的重要工具.现有的层次主题模型大多通过在主题模型中引入nCRP构造方法,为文档主题提供树形结构的先验分布,但无法生成具有明确领域涵义的主题层次结构,即领域主题层次.同时,领域主题不仅存在层次关系,而且不同父主题下的子主题之间还存在子领域方面共享的关联关系,在现有主题关系研究中没有合适的模型来生成这种领域主题层次.为了从领域文本中自动、有效地挖掘出领域主题的层次关系和关联关系,在4个方面进行创新研究.首先,通过主题共享机制改进nCRP构造方法,提出nCRP+层次构造方法,为主题模型中的主题提供具有分层主题方面共享的树形先验分布;其次,结合nCRP+和HDP模型构建重分层的Dirichlet过程,提出rHDP(reallocated hierarchical Dirichlet processes)层次主题模型;第三,结合领域分类信息、词语语义和主题词的领域代表性,定义领域知识,包括基于投票机制的领域隶属度、词语与领域主题的语义相关度和层次化的主题-词语贡献度;最后,通过领域知识改进rHDP主题模型中领域主题和主题词的分配过程,提出结合领域知识的层次主题模型rHDP_DK(rHDP with domain knowledge),并改进采样过程.实验结果表明,基于nCRP+的层次主题模型在评价指标方面均优于基于nCRP的层次主题模型(hLDA,nHDP)和神经主题模型(TSNTM);通过rHDP_DK模型生成的主题层次结构具有领域主题层次清晰、关联子主题的主题词领域差异明确的特点.此外,该模型将为领域主题层次提供一个通用的自动挖掘框架. 展开更多
关键词 层次主题模型 领域分类信息 词语语义 主题关联关系 层次化的采样过程 领域主题层次
下载PDF
基于均匀相位采样提高阻抗谱测量精度的研究
16
作者 王选择 蔡玉雄 +2 位作者 尹晋平 翟中生 冯维 《科学技术与工程》 2024年第2期604-610,共7页
周期性信号采样中,等效采样利用较低采样频率的A/D转换实现高频周期信号的采集,一定程度上弥补欠采样测量精度低的缺陷。为了有效地提高高频测量中阻抗谱测量精度与稳定性,提出一种基于等效采样思想的均匀相位采样的阻抗谱测量方法。利... 周期性信号采样中,等效采样利用较低采样频率的A/D转换实现高频周期信号的采集,一定程度上弥补欠采样测量精度低的缺陷。为了有效地提高高频测量中阻抗谱测量精度与稳定性,提出一种基于等效采样思想的均匀相位采样的阻抗谱测量方法。利用单片机共时钟基准的模/数转换器(digital to analog convertor,DAC)与数/模转换器(analog to digital convertor,ADC)模块,在完成激励信号产生、输入输出信号同步采集的基础上,合理设计激励信号频率、采集频率与信号重构方法,实现高频信号单周期内均匀相位分布的等效高频采样,同时为克服常规A/D转换速度条件下难以准确实现高频阻抗谱测量的问题提供了新思路。从误差假设与拟合算法的角度,理论上分析证明了该方法降低误差的原因。并通过两种等效电路模型的阻抗谱测量对比实验,表明该方法在所设计的20~100 kHz高频段上,阻抗测量精度与稳定性得到了显著的提高。 展开更多
关键词 等效采样 均匀相位采样 阻抗谱 畸变误差
下载PDF
基于邻域采样的多任务图推荐算法
17
作者 张俊三 肖森 +3 位作者 高慧 邵明文 张培颖 朱杰 《计算机工程与应用》 CSCD 2024年第9期172-180,共9页
近年来,图神经网络(GNN)成为解决协同过滤的主流方法之一。它通过构建用户-物品图,模拟用户与物品的交互关系,并用GNN学习它们的特征表示。尽管现有在模型结构上的研究已取得了较大进展,但如何在图结构上更有效地进行负采样仍未有效解... 近年来,图神经网络(GNN)成为解决协同过滤的主流方法之一。它通过构建用户-物品图,模拟用户与物品的交互关系,并用GNN学习它们的特征表示。尽管现有在模型结构上的研究已取得了较大进展,但如何在图结构上更有效地进行负采样仍未有效解决。为此,提出一种基于邻域采样的多任务图推荐算法。该算法提出了一种基于GNN的邻域采样策略,该策略以每个用户为中心构建子图,将次高阶物品作为用户邻域采样的负样本,可以更有效地挖掘强负样本并提高采样质量。通过GNN对图结点进行信息聚合与特征提取,得到结点的最终嵌入表示。设计一种余弦边际损失来过滤部分冗余负样本,以有效减少采样过程中的噪声数据。同时,该算法引入了多任务策略对模型进行联合优化,以增强模型的泛化能力。在3个公开数据集上进行的大量实验表明,该算法在大多数情况下明显优于其他主流算法。 展开更多
关键词 图神经网络 协同过滤 负采样 邻域采样 余弦边际损失 多任务策略
下载PDF
小行星样品密封设计及验证
18
作者 王春勇 马动涛 +3 位作者 王名亮 王波 陆登柏 杜永刚 《真空科学与技术学报》 CAS CSCD 2024年第2期110-114,共5页
中国计划开展探测编号为2016H03的近地小行星并采集样品返回地面,测定小行星样品的物理性质、化学成分与矿物成分,为小行星起源与演化、太阳系的形成与演化过程提供科学依据。针对中国首次近地小行星采样封装任务,设计多种样密封方案,... 中国计划开展探测编号为2016H03的近地小行星并采集样品返回地面,测定小行星样品的物理性质、化学成分与矿物成分,为小行星起源与演化、太阳系的形成与演化过程提供科学依据。针对中国首次近地小行星采样封装任务,设计多种样密封方案,综合考虑密封力、密封面样品颗粒污染物防护等因素,采用双弹性体径向密封方案,并开展密封方案验证工作,通过高温、低温及模拟尘埃污染漏率试验,密封漏率优于5×10^(-6)Pa·m^(3)·s^(-1),满足小行星样品密封要求。 展开更多
关键词 小行星 低温硅橡胶 样品密封 径向密封
原文传递
改进RRT算法的采摘机械臂路径规划
19
作者 赵辉 郑缙奕 +1 位作者 岳有军 王红君 《重庆理工大学学报(自然科学)》 CAS 2024年第1期338-345,共8页
针对采用传统的快速随机扩展树(RRT)算法的采摘机械臂在果园工作环境中搜索路径时间长,最终路径不平滑、拐点多等问题,提出了一种改进的RRT避障算法。改进的算法采用高斯采样策略,减少了采样的随机性,避免产生更多不必要的随机树,增加... 针对采用传统的快速随机扩展树(RRT)算法的采摘机械臂在果园工作环境中搜索路径时间长,最终路径不平滑、拐点多等问题,提出了一种改进的RRT避障算法。改进的算法采用高斯采样策略,减少了采样的随机性,避免产生更多不必要的随机树,增加规划的导向性;再添加A*代价函数去除路径的冗余点,最后使用贪婪算法简化路径,减少拐点,让机械臂可以快速、准确、平稳地沿着最佳路径运动到目标点。仿真表明,改进后的算法有效地减少了路径规划的时间,缩短了路径长度,具有良好的可行性和有效性。 展开更多
关键词 机械臂 RRT 高斯采样 贪婪算法
下载PDF
蜜蜂资源形态测定的采样与保存方法研究
20
作者 庄明亮 李剑飞 +6 位作者 迟永娟 葛蓬 王志 蒋海宾 王进州 戚竞文 李志勇 《特产研究》 2024年第2期22-24,29,共4页
形态测定是蜜蜂种质资源评价必不可少的技术手段,本研究旨在优化采样与保存方法来提高蜜蜂形态测定工作的效率。通过各试验组不同采样与保存方法对比蜜蜂样品的伸吻率、组织损坏数量、色度及韧性的变化。结果表明,试验组B毙杀20 s、30s... 形态测定是蜜蜂种质资源评价必不可少的技术手段,本研究旨在优化采样与保存方法来提高蜜蜂形态测定工作的效率。通过各试验组不同采样与保存方法对比蜜蜂样品的伸吻率、组织损坏数量、色度及韧性的变化。结果表明,试验组B毙杀20 s、30s的伸吻率差异不显著(P>0.05),但均显著高于其他试验组(P<0.05);试验组D的蜜蜂组织损坏数量显著低于试验组E、F、G和对照组(P<0.05);在4℃环境中保存1~3个月对蜜蜂样本的色度和样本的韧性均没有影响。蜜蜂资源形态测定的样品建议使用2L/min流速的CO_(2)毙杀20 s,浸泡在75%酒精和0.5%甘油的保存液中,保存3个月内完成形态测定工作。 展开更多
关键词 蜜蜂 采样 保存 资源鉴定 形态测定
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部