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Wrist circumference: A new marker for insulin resistance in African women with polycystic ovary syndrome 认领
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作者 Chantal Anifa Amisi Massimo Ciccozzi Paolo Pozzilli 《世界糖尿病杂志:英文版(电子版)》 2020年第2期42-51,共10页
BACKGROUND Insulin resistance(IR)is the main complication found in 35%-80%of women with polycystic ovary syndrome(PCOS).However,there is no definite consensus regarding which marker to use for its assessment in PCOS w... BACKGROUND Insulin resistance(IR)is the main complication found in 35%-80%of women with polycystic ovary syndrome(PCOS).However,there is no definite consensus regarding which marker to use for its assessment in PCOS women.Research has shown that hyperinsulinemia is correlated with increased bone mass.Given that most women with PCOS are insulin resistant,which is independent from body fat and characterized by hyperinsulinemia,it could be hypothesized that there would be an increased bone mass in the patient as a result.Subsequently,increased bone mass could be measured using the wrist circumference method.AIM To assess the wrist circumference as an easy-to-detect marker of IR in Congolese women with PCOS.METHODS Seventy-two Congolese women with PCOS and seventy-one controls from the same ethnic group,were enrolled in the study(mean age 24.33±5.36 years).Fasting biochemical parameters,and the Homeostasis Model Assessment of insulin resistance(HOMA-IR)and body composition were evaluated.The nondominant wrist circumference was measured manually,as was the waist circumference(WC),hip circumference,height and weight.Calculated measures included evaluation of body mass index(BMI),Waist-to-Height(WHtR)and Waist-to-hip ratio(WHR).In addition,body composition was assessed by Bioelectrical Impedance Analysis using a body fat analyzer.RESULTS The non-dominant wrist circumference was more closely correlated with HOMAIR(r=0.346;P=0.003)and was the best anthropometrical marker correlated with IR(P=0.011)compared with other anthropometrical markers in women with PCOS:Dominant Wrist Circumference(r=0.315;P=0.007),Waist Circumference(WC)(r=0.259;P=0.028),BMI(r=0.285;P=0.016),WHR(r=0.216;P=0,068)and WHtR(r=0.263;P=0.027).The diagnostic accuracy of the non-dominant wrist circumference for the presence or absence of IR using Receiver-operating characteristic(ROC)curve analysis showed that the area under the ROC curve was 0.72.A cutoff value for the non-dominant wrist circumference of 16.3 cm was found to be the best predictor of IR 展开更多
关键词 WRIST CIRCUMFERENCE INSULIN RESISTANCE Polycystic ovary syndrome Congolese WOMEN Sub-Saharan African WOMEN MARKER of INSULIN RESISTANCE Homeostasis Model Assessment of INSULIN RESISTANCE Easy-to-detect MARKER
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Microstructure and high-temperature properties of Fe-Ti-Cr-Mo-B-C-Y2O3 laser cladding coating 认领
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作者 Min Zhang Xinhong Wang +1 位作者 Shushuai Liu Kaili Qu 《稀土学报:英文版》 SCIE EI CAS CSCD 2020年第6期683-688,共6页
Fe-based composite coatings were fabricated on 5 CrNiMo die steel by laser beam melting a precursor mixture of ferrotitanium,ferrochromium,ferromolybdenum,B4 C and Y2 O3 powders.Micro structure and properties of the c... Fe-based composite coatings were fabricated on 5 CrNiMo die steel by laser beam melting a precursor mixture of ferrotitanium,ferrochromium,ferromolybdenum,B4 C and Y2 O3 powders.Micro structure and properties of the coatings were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive spectrometer(EDS),resistance furnace and high-temperature tribometer.The results show that(Ti,Mo)C particles with flower-like and(Ti,Mo)B2 with block-like shapes are in situ formed during laser cladding.Volume faction of multiple ceramic particles increases with the increasing of Y2 O3.The cumulative oxidation mass of the coating with 2 wt% Y2 O3 is decreased by one-third than that of the coating without Y2 O3.The oxidation layer of the coating with Y2 O3 is getting smooth.Meanwhile,high temperature wear volume loss of the coating with 2 wt% Y2 O3 is about 40% that of the coating without Y2 O3.The coating with 2 wt% Y2 O3 shows a smoother wear scar and few flat grooves are observed after high temperature wear test. 展开更多
关键词 Laser composite coatings Rare earth oxide High-temperature oxidation resistance High-temperature wear resistance
Resistance of <i>Plasmodium falciparum</i>to Sulfadoxine-Pyrimethamine (<i>Dhfr</i>and <i>Dhps</i>) and Artemisinin and Its Derivatives (K13): A Major Challenge for Malaria Elimination in West Africa 认领
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作者 Valérie B. Bazie Abdoul Karim Ouattara +5 位作者 Tani Sagna Tegwindé Rebeca Compaore Serge Théophile Soubeiga Pegdwendé Abel Sorgho Albert Théophane Yonli Jacques Simpore 《生物科学与医学(英文)》 2020年第2期82-95,共14页
The spread of resistance to antimalarials is a major public health problem worldwide and especially in sub-Saharan Africa where the highest morbidity and mortality rates are found with a critical scarcity of data on r... The spread of resistance to antimalarials is a major public health problem worldwide and especially in sub-Saharan Africa where the highest morbidity and mortality rates are found with a critical scarcity of data on resistance. The objective of this review is to describe the mutations in the pfdhfr, pfdhps and k13 genes associated with resistance to artemisinin and Sulfadoxine-Pyrimethamine reported in West Africa during the decade 2007 to 2017 followed by a meta-analysis of their prevalence. A bibliographic search on the MEDLINE, PubMed, EMBASE and Sciences Direct databases made it possible to find 405 scientific papers relating to resistance to artemisinin and to Sulfadoxine-Pyrimethamine during the period 2007-2017. The analysis has concerned 217 scientific articles after the elimination of duplicates with 57 articles included in this review after the examination of titles and abstracts. The results of the present review show that the dhfr and dhps mutants are widespread in sub-Saharan Africa. Although, Kelch 13 mutants from Southeast Asia associated with artemisinin resistance are still absent in West Africa, studies have reported the presence of synonymous or non-K13 mutations correlated with a delay in parasite clearance in Burkina Faso (2.26%), Senegal (5.5%) and Togo (1.8%). The increased prevalence of dhfr and dhps mutants in West Africa could jeopardize its use for intermittent preventive treatment in the near future. Despite the absence of strains resistant to artemisinin-based combination therapy in the West African region, increased surveillance is necessary to prevent the rapid occurrence of possible resistance, especially in the context of synonymous or non-K13 mutations correlated with a delay in parasitic clearance. 展开更多
关键词 RESISTANCE Mutations ARTEMISININ Sulfadoxine-Pyrimethamine WEST AFRICA
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Genetic Diversity, Antimicrobial Resistance, and Virulence Genes of Aeromonas Isolates from Clinical Patients, Tap Water Systems, and Food 认领
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作者 MENG Shuang WANG Yong Lu +7 位作者 LIU Chen Geng YANG Jing YUAN Min BAI Xiang Ning JIN Dong LIANG Jun Rong CUI Zhi Gang LI Juan 《生物医学与环境科学:英文版》 SCIE CAS CSCD 2020年第6期385-395,共11页
Objective This study aimed to evaluate the genetic diversity,virulence,and antimicrobial resistance of Aeromonas isolates from clinical patients,tap water systems,and food.Methods Ninety Aeromonas isolates were obtain... Objective This study aimed to evaluate the genetic diversity,virulence,and antimicrobial resistance of Aeromonas isolates from clinical patients,tap water systems,and food.Methods Ninety Aeromonas isolates were obtained from Ma’anshan,Anhui province,China,and subjected to multi-locus sequence typing(MLST)with six housekeeping genes.Their taxonomy was investigated using concatenated gyr B-cpn60 sequences,while their resistance to 12 antibiotics was evaluated.Ten putative virulence factors and several resistance genes were identified by PCR and sequencing.Results The 90 Aeromonas isolates were divided into 84 sequence types,80 of which were novel,indicating high genetic diversity.The Aeromonas isolates were classified into eight different species.PCR assays identified virulence genes in the isolates,with the enterotoxin and hemolysin genes act,aer A,alt,and ast found in 47(52.2%),13(14.4%),22(24.4%),and 12(13.3%)of the isolates,respectively.The majority of the isolates(≥90%)were susceptible to aztreonam,imipenem,cefepime,chloramphenicol,gentamicin,tetracycline,and ciprofloxacin.However,several resistance genes were detected in the isolates,as well as a new mcr-3 variant.Conclusions Sequence type,virulence properties,and antibiotic resistance vary in Aeromonas isolates from clinical patients,tap water systems,and food. 展开更多
关键词 AEROMONAS Multi-locus sequence typing Multidrug resistance Virulence gene Antimicrobial resistance gene
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R取值范围对RLC串联暂态过程临界阻尼电阻的影响 认领
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作者 张钰新 张力月 +2 位作者 金泓君 孔睿麟 王丽 《大学物理实验》 2020年第2期63-65,96,共4页
在运用“RLC串联电路暂态过程中阻尼电阻与振幅和阻尼度之间关系”求临界阻尼电阻的方法中,讨论了电阻取值范围对其测量结果的影响。研究表明,当C=0.005μF,L=100 mH,电阻R的取值等于或大于800Ω时,该方法无法准确给出临界电阻的数值。
关键词 RLC串联电路 暂态过程 电阻 临界阻尼电阻
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Measurement of Electrical Resistance of Liquid Electrolytes and Materials Containing Them 认领
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作者 Kirill V. Dobrego Mikhail A. Chumachenko +2 位作者 Olga V. Boiprav Nikolay N Grinchik Halina A. Pukhir 《电磁分析与应用期刊(英文)》 2020年第2期7-14,共8页
Measurement of the electrical conductivity of electrolytes and heterogeneous materials containing them is accompanied by numerous physical and electrochemical processes, complicating measuring and interpretation of da... Measurement of the electrical conductivity of electrolytes and heterogeneous materials containing them is accompanied by numerous physical and electrochemical processes, complicating measuring and interpretation of data. As a result, the measurement of the electrical conductivity of such a system is a difficult and not finally resolved problem. The new method of resistance measurement of the electrolytic systems is substantiated and tested on example of heterogeneous electrolytic system “lignin-calcium chloride water solution” in this article. The method is based on measurement of resistance of the electrolytic system at different voltages (DC) on the cell and the consequent approximation of the acquired data taking into consideration volume charges and potential barriers arising on the boarders of electrodes and electrolytic materials. Extrapolation of the resistance to the limiting small current lets one obtain a characteristic value of the active resistance of the electrolytic system. The method is technically simple, inexpensive and has several advantages compared to the methods based on AC measurements. 展开更多
关键词 ELECTROLYTE CONDUCTIVITY Conductometry RESISTANCE
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Association between the Phenotypes and Genotypes of Antimicrobial Resistance in Haemophilus parasuis Isolates from Swine in Quang Binh and Thua Thien Hue Provinces, Vietnam 认领
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作者 Chao Nguyen Van Lijun Zhang +4 位作者 Tam Vu Thi Thanh Hung Pham Hoang Son Tuan Tran Ngoc Qi Huang Rui Zhou 《工程(英文)》 SCIE EI 2020年第1期40-48,共9页
Haemophilus parasuis (H. parasuis) is one of the bacterial pathogens of great concern as it causes huge economic losses to the swine industry worldwide. One of the reasons why the control of H. parasuis has failed is ... Haemophilus parasuis (H. parasuis) is one of the bacterial pathogens of great concern as it causes huge economic losses to the swine industry worldwide. One of the reasons why the control of H. parasuis has failed is the increase in antimicrobial resistance (AMR). The country of Vietnam has the second-largest pig production in Asia. However, there is still a lack of data about the AMR prevalence of H. parasuis in Vietnam.The purpose of this study is to investigate the prevalence of AMR and analyze the association between AMR and AMR genes (ARGs). The H. parasuis strains used in this research were isolated from swine in the Quang Binh and Thua Thien Hue Provinces, Central Vietnam, as reported in our previous study. All of the strains were tested for AMR against 25 antibacterial agents using the broth microdilution method and for the presence of ARGs using the polymerase chain reaction (PCR) method. The tested strains were shown to have a high frequency of resistance to trimethoprim/sulfamethoxazole (94.6%), followed by resistance to colistin, chloramphenicol, gentamicin, penicillin, lincomycin, and amoxicillin. The most prevalent ARGs in these strains were blaTEM-1 (94.6%), int (76.8%), gyrA (58.9%), and rmtD (50.0%). Cefuroxime, chloramphenicol, and tobramycin resistances were strongly correlated with the presence of the ARGs blaROB-1 (odds ratio (OR) = 26.3, 95% confidence interval (CI) 2.7–255.7, p = 0.002), catl (OR = 25.1, 95% CI 2.4–258.9, p = 0.004), and strB (OR = 23.5, 95% CI 2.6–212.6, p = 0.001), respectively.This study reveals for the first time the current situation of H. parasuis AMR in Central Vietnam, which is helpful for the clinical control of this disease, as well as for the development of policies and clinical practice guidelines to reduce AMR in swine production in Central Vietnam. 展开更多
关键词 HAEMOPHILUS parasuis ANTIMICROBIAL RESISTANCE ANTIMICROBIAL RESISTANCE gene VIETNAM
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Bacteriology and Antibiotic Sensibility Associated with Extracted Carious Teeth: A Cross Sectional Study at Komfo Anokye Teaching Hospital, Kumasi, Ghana 认领
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作者 Ama Agyeibea Amuasi Alexander Oti Acheampong +4 位作者 Collins Kokuro Alex Ofori Kpedekpo Yayra Joseph Abu-Sakyi Francis Adu-Ababio 《口腔学期刊(英文)》 2020年第5期87-96,共10页
Background: Many oral bacterial species forming the normal flora present as a biofilm in the oral cavity. Dental caries results when there is an imbalance of pathogenic bacteria within these biofilms. Aim: This study ... Background: Many oral bacterial species forming the normal flora present as a biofilm in the oral cavity. Dental caries results when there is an imbalance of pathogenic bacteria within these biofilms. Aim: This study sought to isolate and identify the bacterial species associated with extracted carious teeth and their susceptibility pattern towards commonly employed antimicrobial agents used at the Komfo Anokye Teaching Hospital (KATH). Methodology: A descriptive cross-sectional study carried out on thirty-three extracted carious teeth samples collected by convenient sampling from patients attending the Oral Health Directorate-KATH. All samples were collected from the 11th of March 2019 to the 6th of April 2019. Data was collected using 5 ml peptone water and a case study form. Analysis was done using SPSS version 25 and Microsoft Excel version 10. Results: Twenty (61%) samples were obtained from female patients and thirteen samples (39%) from male patients. Streptococcus spp had the highest occurrence (32.25%) with the least isolated being Pseudomonas and E. coli spp (6.45%). Antibiotic susceptibility test revealed Pseudomonas spp was resistant to all the eight antibiotics used in this study. All bacterial isolates were resistant to Cefuroxime and penicillin except Staphylococcus and Streptococcus spp. Conclusion: The commonest isolates associated with dental caries in KATH were Streptococcus, Bacillus and Staphylococcus spp. In this study most of the isolated species were resistant to common antibiotics employed in the Oral Health Directorate in KATH (amoxicillin/clavulanic, ampicillin and penicillin). From the current study the most effective antibiotic observed was meropenem (23%) with penicillin (3%) being least effective in treating infections of caries. 展开更多
关键词 CARIES BACTERIA Teeth Antibiotic RESISTANCE
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Antibacterial Activity of Essential Oil from <i>Citrus aurantifolia</i>(Christm.) Swingle Peels against Multidrug-Resistant Bacterial Isolates 认领
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作者 N. Torimiro B. R. Adegun +1 位作者 O. E. Abioye R. K. Omole 《微生物学(英文)》 2020年第5期214-223,共10页
The study investigated the antibacterial activity of essential oil from the peel of Citrus aurantifolia against eleven multidrug-resistant (MDR) bacterial isolates of clinical origin. The Kirby-Bauer disc diffusion me... The study investigated the antibacterial activity of essential oil from the peel of Citrus aurantifolia against eleven multidrug-resistant (MDR) bacterial isolates of clinical origin. The Kirby-Bauer disc diffusion method was used to determine the antibiotic resistance profile of the isolates. Essential oil (EO) from the peels of lime purchased at a market in Ile-Ife was extracted by the hydro-distillation method, while the sensitivity of the isolates to EO was done via agar well diffusion method. The minimum inhibitory and minimum bactericidal concentrations (MIC and MBC) of the EO against the tested isolates were determined following standard methods. All the tested isolates exhibited multidrug resistance (MDR) characteristics. The multiple antibiotics resistant indexes (MARI%) for Gram-positive bacterial isolates ranged between 70% and 100% while that of Gram-negative was 100%. The yield of EO was 1% and the EO demonstrated activities at 25%, 50% and 100% v/v against the MDR bacterial isolates. The activity of EO was mostly not significantly different at the same concentration for all the isolates, and at different concentrations for each of the isolates. The MIC range for Gram-negative and Gram-positive isolates was between 0.195% to 3.125% v/v and 0.39% to 3.125% respectively while the range was between 1.563% to 3.125% and 0.781% to 6.250% v/v for MBC respectively. The study showed that EO from the peel of lime fruits demonstrated excellent in vitro antibacterial activity against MDR bacterial isolates. This potential can be further explored as an alternative for the treatment and management of infections caused by MDR bacterial isolates. 展开更多
关键词 CITRUS aurantifolia Essential Oil BACTERIA ANTIBACTERIAL Resistance
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Verification of Glyphosate Resistance, Lepidopteran Resistance and Wide Compatibility of Male Sterile Line E1C4008S in Rice 认领
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作者 ZENG Qiang DENG Lihua +6 位作者 HU Wenbin HE Xingjian MENG Qiucheng YU Jianghui LI Jinjiang WENG Lushui XIAO Guoying 《水稻科学:英文版》 SCIE CSCD 2020年第3期215-226,共12页
Weeds and insect pests are two important biotic stresses resulting in yield loss in rice, and wide compatibility is the essential characteristic of breeding inter-subspecific hybrid rice. This study focused on glyphos... Weeds and insect pests are two important biotic stresses resulting in yield loss in rice, and wide compatibility is the essential characteristic of breeding inter-subspecific hybrid rice. This study focused on glyphosate resistance, lepidopteran resistance and wide compatibility as well as identification of molecular and some agronomic characteristics of transgenic male sterile line E1 C4008 S. The results indicated that glyphosate resistance gene Epsps^# and lepidopteran resistance gene Cry1 ca^# were transferred into japonica wide compatibility male sterile line 4008 S by Agrobacterium-mediated method, and four independent transformation events named E1 C4008 S-1, E1 C4008 S-2, E1 C4008 S-3 and E1 C4008 S-4 were obtained, in which E1 C4008 S-3 and E1 C4008 S-4 were of single copy insertion. The EPSPS protein contents of E1 C4008 S-3 and E1 C4008 S-4 in different organs were significantly different both in descending order of leaf > stem > root, and ranged from 300.58 to 1410.69 μg/g at the tillering stage. The glyphosate tolerable concentration(dosage) of E1 C4008 S-3 and E1 C4008 S-4 reached at least 16 g/L(54.42 kg/hm^2), and the seeds of E1 C4008 S-4 can germinate normally on the medium containing 1 g/L glyphosate. The CRY1 C protein contents of E1 C4008 S-3 and E1 C4008 S-4 in different organs were significantly different both in descending order of leaf > stem > root, and ranged from 0.62 to 2.43 μg/g at the tillering stage. The larvae mortalities of rice leaf rollers fed on leaves of E1 C4008 S-3 and E1 C4008 S-4 for 5 d were 95.35% and 97.77%, respectively, while the average mortalities of silkworms fed with protein extracts from leaves of E1 C4008 S-3 and E1 C4008 S-4 reached 94.55% and 83.64%, respectively. The results suggested that wide compatibility and evaluated agronomic traits of E1 C4008 S-4 were not significantly changed by insertion of the exogenous genes. Overall, a novel male sterile germplasm with glyphosate resistance, lepidopteran resistance and wide compatibility was verified to be dev 展开更多
关键词 RICE GLYPHOSATE RESISTANCE LEPIDOPTERAN RESISTANCE wide compatibility male STERILE line bioengineered crop
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Enhanced oxidation and graphitization resistance of polycrystalline diamond sintered with Ti-coated diamond powders 认领
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作者 Xiaohua Sha Wen Yue +3 位作者 Haichao Zhang Wenbo Qin Dingshun She Chengbiao Wang 《材料科学技术:英文版》 SCIE EI CAS CSCD 2020年第8期64-73,共10页
To improve the oxidation and graphitization resistances of the polycrystalline diamond(PCD), Ti coating was deposited on the diamond powders via magnetic sputtering method, which achieved a uniform Ti C protection bar... To improve the oxidation and graphitization resistances of the polycrystalline diamond(PCD), Ti coating was deposited on the diamond powders via magnetic sputtering method, which achieved a uniform Ti C protection barrier in PCD during the sintering process. The phase compositions, microstructures and thermal stability of Ti-PCD were characterized by X-ray diffraction(XRD), Auger electron spectroscopy(AES),scanning electron microscopy(SEM) and thermal gravimetric-differential scanning calorimetry(TG-DSC).The results demonstrate that the oxidation and graphitization resistances of PCD are strengthened due to the existence of Ti C phase, which acts as an effective inhibitor. The as-received inhibitor delays the oxidation and graphitization of PCD, elevating their initial temperature by ~50°C and ~100°C, respectively. During the annealing treatment of Ti-PCD, the priory oxidation of Ti C, which produces Ti O2 as an oxygen barrier, postpones the diamond oxide. Moreover, the Ti C barrier also protects diamond grains from direct contact with cobalt, thus a lower cobalt-catalytic graphitization, and yields to an improved graphitization resistance of PCD. The enhanced oxidation and graphitization resistances of PCD are of significant importance for practical applications to elevated temperatures. 展开更多
关键词 Polycrystalline diamond Ti-coated diamond powder TiC barrier Oxidation resistance Graphitization resistance
Conserved Immunoglobulin Domain Similarities of Higher Plant Proteins 认领
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作者 Jaroslav Kubrycht Karel Sigler 《计算分子生物学(英文)》 2020年第1期12-44,共33页
The traces of immunoglobulin domain similarities were searched in sequences of higher plants using bioinformatic tools to look for possible early phylogenic structural relationships. 280 thousand sequence IDs, obtaine... The traces of immunoglobulin domain similarities were searched in sequences of higher plants using bioinformatic tools to look for possible early phylogenic structural relationships. 280 thousand sequence IDs, obtained by sixteen types of primary BLAST searches, were differently processed by seventeen selection procedures and an anti-redundant sequence-related approach using JavaScript, PHP, Windows programs and conserved domain searches by means CDD. The resulting seventeen sets of records describing conserved domain similarities of 1323 different sequence IDs yielded a set of next generation (final set) comprising forty-nine records containing superior (“non-refutable”) conserved immunoglobulin domain similarities. The selected sets and their subsets were mapped and subsequently statistically compared with respect to immunoglobulin-related as well as other reciprocal domain linkages. The list of frequently occurring conserved domain similarities concerned first of all domains important for plant and metazoan immunity, e.g. tyrosine kinases accompanying variable immunoglobulin domains in early Metazoa, toll-like receptors, lectin and leucine-rich repeat domains. Detailed description of immunoglobulin domain similarities occurring in the final set was completed by fold analysis of the restricted segments. The data were then discussed with respect to i) immunoglobulin fold evolution, ii) possible structural importance of domains cd14066 (IRAK) and PLN00113 (LRR-associated kinase) for deep evolution of catalytic serine/threonine/tyrosine kinase domains, iii) interatomic, structural and specificity standpoints and iv) traces of antibody-like phosphorylation sites described in our previous paper. 展开更多
关键词 CONSERVED DOMAIN DOMAIN SHUFFLING Deep EVOLUTION EVOLUTION Fold IMMUNOGLOBULIN Kinase Plant Immunity Resistance
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热阻仿真在陶瓷封装电阻计算中的应用 认领
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作者 崔朝探 刘林杰 李玮 《半导体技术》 CAS 北大核心 2020年第3期224-228,共5页
随着半导体封装器件的不断发展,工作电流不断增加,对陶瓷封装的电性能提出了更高要求,而导通电阻是衡量其电性能最重要的参数之一,会影响电路的稳定性和功耗波动。提出了一种陶瓷封装中导通电阻仿真求解的新方法,利用ANSYS软件热阻仿真... 随着半导体封装器件的不断发展,工作电流不断增加,对陶瓷封装的电性能提出了更高要求,而导通电阻是衡量其电性能最重要的参数之一,会影响电路的稳定性和功耗波动。提出了一种陶瓷封装中导通电阻仿真求解的新方法,利用ANSYS软件热阻仿真模型等效求解电阻的方式,实现导通电阻值的精确计算。阐述了热阻模型与电阻模型的等效机理,对比了传统估值法与仿真求解法的计算结果,结果表明,仿真求解法得到的电阻值与实测电阻值更为接近,误差小于5%,而传统估值法误差最高可达30%。仿真求解法计算时间大大缩短,效率更高,还可观察线路的连通关系,错误率远低于传统估值算法。该方法适用于陶瓷封装中不同类型和任意结构的阻值计算,通用性强。 展开更多
关键词 陶瓷封装 导通电阻 热阻仿真模型 等效机理 通用性
The Effects of Different Quality of Exercise on Blood Pressure and Heart Rate in Healthy Female 认领
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作者 Aiesha Mohammed Almutawa Afaf Abdullah Al-Shelash +3 位作者 Buthaynah Mohammed Al-Gazlan Reema Mohammad Al-Sallali Reem Abdullah Al-Marzougi Noorah Saleh Al-Sowayan 《健康(英文)》 2020年第4期425-435,共11页
Blood pressure is a serious disease that may affect a person. It also increases the risk of heart attack and stroke. Exercise may be a major reason for reducing the risk of heart disease in the future. The aim of this... Blood pressure is a serious disease that may affect a person. It also increases the risk of heart attack and stroke. Exercise may be a major reason for reducing the risk of heart disease in the future. The aim of this study is to compare the effects of different types of exercises, such as walking, cross fit, and Swedish on blood pressure and heart rate among a number of physical exercises practitioners and gymnasts. This study was conducted on pioneers of different gyms in the Qassim region after taking ethical procedures and taking the consent of the subjects’ members. The subject size is 39 females between 14 - 38 of age. They were divided into three groups;each one had 13 members. The first experimental group practiced walking, the second practiced crossfit;lastly, the third experimental group practiced the Swedish sport. A device was used to measure the blood pressure and heart rate. The measurement was taken 5 minutes pre and post the rest period. After that the measurements were taken 15 minutes after the rest period. SPSS software was implemented to analyze the data. The significant result was that the three groups showed low blood pressure after performing various exercises while the heart rate increased in all three. This study proved that the severity of low blood pressure depends on the intensity of the exercise. The findings revealed that the highest exercise intensity is CrossFit, but also it is the highest of the decrease in blood pressure. The researchers recommend that readers should consider the importance of exercising as it is maybe a method for preventing from high blood pressure. 展开更多
关键词 Hypertension INTENSITY Resistance SYSTOLIC Blood Pressure
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文章速递左旋紫草素对顺铂耐药人宫颈癌HeLa细胞的逆转作用研究 认领
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作者 杜春双 马亚妮 +3 位作者 王帅 张飞 张洁 桑广健 《中国药房》 CAS CSCD 北大核心 2020年第15期1867-1873,共7页
目的:探讨左旋紫草素(L-SHK)对顺铂(DDP)耐药人宫颈癌HeLa细胞(HeLa/DDP)的逆转作用及其可能机制。方法:以人宫颈癌HeLa细胞株为研究对象,以DDP诱导获得HeLa/DDP耐药细胞;采用CCK-8法测定HeLa/DDP细胞的耐药指数以及不同剂量L-SHK(0.125... 目的:探讨左旋紫草素(L-SHK)对顺铂(DDP)耐药人宫颈癌HeLa细胞(HeLa/DDP)的逆转作用及其可能机制。方法:以人宫颈癌HeLa细胞株为研究对象,以DDP诱导获得HeLa/DDP耐药细胞;采用CCK-8法测定HeLa/DDP细胞的耐药指数以及不同剂量L-SHK(0.125、0.25、0.5、1、2、4、8、16μmol/L)对该细胞的抑制率、半数抑制浓度(IC50)和逆转倍数;采用流式细胞术检测低、中、高剂量L-SHK(0.3、0.6、1.2μmol/L)联合DDP对HeLa/DDP细胞周期及凋亡率的影响,采用Western blotting法检测低、中、高剂量L-SHK(0.3、0.6、1.2μmol/L)联合DDP对HeLa/DDP细胞凋亡相关蛋白[剪切型胱天蛋白酶3(Cleaved caspase-3)、Bcl-2、Bax]表达的影响。结果:所得HeLa/DDP细胞的耐药指数为11.8。L-SHK对HeLa/DDP细胞的抑制率有随剂量增加而逐渐升高的趋势。与单用DDP比较,DDP+低、中、高剂量L-SHK组细胞的IC50值均显著降低,且呈剂量依赖性(P<0.05);DDP+低、中、高剂量L-SHK组的逆转倍数分别为1.38、2.80、6.71。与空白对照组比较,各药物组G0/G1期、S期细胞比例,各剂量L-SHK联用组细胞的早期、晚期凋亡率及总凋亡率以及Bax、Cleaved caspase-3蛋白的表达量均显著升高;各药物组G2/M期细胞比例以及各剂量L-SHK联用组Bcl-2蛋白的表达量均显著降低(P<0.05)。与DDP组比较,各剂量L-SHK联用组S期、G2/M期细胞比例和Bcl-2蛋白的表达量均显著降低;G0/G1期细胞比例,早期、晚期凋亡率及总凋亡率和Bax、Cleaved caspase-3蛋白的表达量均显著升高(P<0.05)。结论:HeLa/DDP细胞对DDP具有一定的耐药性,L-SHK可逆转这种耐药性。L-SHK和DDP联用可促进HeLa/DDP细胞凋亡,且作用强于DDP单用;这种作用可能与影响细胞周期、调控凋亡相关蛋白的表达有关。 展开更多
关键词 人宫颈癌HeLa细胞 左旋紫草素 顺铂 耐药 凋亡 细胞周期 凋亡蛋白 逆转作用 机制
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基于四线制的电阻自动测量研究与实现 认领
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作者 张小辉 吴传贵 +1 位作者 王纬国 李珊珊 《航空维修与工程》 2020年第4期42-45,共4页
为了实现对多型座椅不同组件电气性能的自动测量,需要研制座椅电气自动综合检测设备。针对座椅组件电阻测量的导通性指标测试任务,提出了一种基于工控机、信号切换模块、数字多用表和通用连接模块的测试方案,并开发了自动测试控制程序,... 为了实现对多型座椅不同组件电气性能的自动测量,需要研制座椅电气自动综合检测设备。针对座椅组件电阻测量的导通性指标测试任务,提出了一种基于工控机、信号切换模块、数字多用表和通用连接模块的测试方案,并开发了自动测试控制程序,实现了对多型座椅电气组件电阻的快速准确自动检测。 展开更多
关键词 四线制 座椅组件 电阻 自动测量
新型流化除雾器除雾性能实验研究 认领
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作者 张成刚 陈旺生 +2 位作者 朱能天 涂阳哲 韩军 《烧结球团》 北大核心 2020年第1期67-72,共6页
针对目前除雾器存在的除雾效率不高、易堵塞、成本高等问题,提出一种新型的流化除雾器,其具有高效、低阻、防堵塞等优点。探讨了流化除雾器的除雾原理,并研究了流化除雾器的除雾性能及其影响因素。结果表明:流化除雾器除雾机理主要为惯... 针对目前除雾器存在的除雾效率不高、易堵塞、成本高等问题,提出一种新型的流化除雾器,其具有高效、低阻、防堵塞等优点。探讨了流化除雾器的除雾原理,并研究了流化除雾器的除雾性能及其影响因素。结果表明:流化除雾器除雾机理主要为惯性碰撞、拦截;除雾器阻力随着流化风速、除雾介质堆积厚度和表观密度的增大而增大,当除雾介质粒径为30 mm,堆积厚度为16 cm,进口雾滴质量浓度为90 g/m^3,流化风速由5.7 m/s增大至7.5 m/s时,排放质量浓度由4.17 mg/m^3增大至41.94 mg/m^3,除雾效率均高达99.95%以上,阻力均在210 Pa左右,表明流化除雾器具有良好的除雾性能,且由于除雾介质处于流化状态,因此可有效防止除雾器堵塞。 展开更多
关键词 除雾器 除雾机理 除雾效率 排放质量浓度 阻力
拖曳水池标模阻力复合航次试验不确定度分析 认领
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作者 张立 陈建挺 +1 位作者 陈伟民 马雪泉 《船舶工程》 CSCD 北大核心 2020年第4期38-43,126,共7页
参考国际拖曳水池会议(ITTC)推荐的规程,对船模拖曳水池的阻力试验进行不确定度分析。根据船模阻力试验的流程,确定试验过程中的误差源;根据不确定度的传递方程,确定误差源对试验结果的影响;基于一艘船模标准模型进行带舵的复合航次重... 参考国际拖曳水池会议(ITTC)推荐的规程,对船模拖曳水池的阻力试验进行不确定度分析。根据船模阻力试验的流程,确定试验过程中的误差源;根据不确定度的传递方程,确定误差源对试验结果的影响;基于一艘船模标准模型进行带舵的复合航次重复试验,并根据试验误差源分析得到试验结果的不确定度。在此基础上,提出降低试验不确定度的方法。分析结果表明,在95%置信水平下(k=2),总阻力及其主要水动力系数的不确定度均小于1%,试验结果可作为标模基准校验使用。 展开更多
关键词 拖曳水池 标模 阻力 不确定度分析
犊牛腹泻源大肠杆菌耐药情况及HPI相关基因的检测 认领
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作者 高海慧 黎玉琼 +4 位作者 高小斐 王培柱 吴学青 康晓冬 梁小军 《中国畜牧兽医》 CAS 北大核心 2020年第6期1942-1951,共10页
本研究旨在明确犊牛腹泻源性大肠杆菌的耐药情况、强毒力岛(HPI)标志基因及相关基因的携带情况,以及大肠杆菌分离株与HPI携带的关系。采集犊牛病理性腹泻样本158份,采用麦康凯培养基和伊红美蓝培养基进行筛选,镜检符合大肠杆菌形态的进... 本研究旨在明确犊牛腹泻源性大肠杆菌的耐药情况、强毒力岛(HPI)标志基因及相关基因的携带情况,以及大肠杆菌分离株与HPI携带的关系。采集犊牛病理性腹泻样本158份,采用麦康凯培养基和伊红美蓝培养基进行筛选,镜检符合大肠杆菌形态的进行VITEK 2 Compact生化鉴定和PCR鉴定,采用K-B纸片法对大肠杆菌分离株进行药敏试验,应用PCR方法进行分离株HPI相关基因携带情况的检测。结果显示,共分离得到75株大肠杆菌,分离株对阿莫西林、哌拉西林、氨苄西林、头孢唑啉、氟苯尼考、恩诺沙星、四环素的耐药率均>90%,对头孢氨苄、头孢拉定、头孢曲松、环丙沙星、诺氟沙星和氧氟沙星的耐药率均≥60.00%,对阿米卡星较敏感,耐药率为9.33%;75株大肠杆菌全部耐3种以上药物,多重耐药(≥10)的菌株占85.33%,耐药谱集中在耐14~17种药物,5株对19种药物全部耐药。HPI标志基因irp2的阳性率为100%,其他相关基因fyuA、irp3、irp5、irp8和ytbA的检出率在66.00%以上。综上所述,宁夏地区犊牛腹泻源性大肠杆菌耐药普遍,多重耐药现象严重。 展开更多
关键词 犊牛腹泻 大肠杆菌 耐药 强毒力岛
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Genetic progress in stem lodging resistance of the dominant wheat cultivars adapted to Yellow-Huai River Valleys Winter Wheat Zone in China since 1964 认领
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作者 ZHANG Hong-jun LI Teng +9 位作者 LIU Hong-wei MAI Chun-yan YU Guang-jun LI Hui-li YU Li-qiang MENG Ling-zhi JIAN Da-wei YANG Li LI Hong-jie ZHOU Yang 《农业科学学报:英文版》 SCIE CAS CSCD 2020年第2期438-448,共11页
Analysis of genetic progress for lodging-related traits provides important information for further improvement of lodging resistance.Forty winter wheat cultivars widely grown in the Yellow-Huai River Valleys Winter Wh... Analysis of genetic progress for lodging-related traits provides important information for further improvement of lodging resistance.Forty winter wheat cultivars widely grown in the Yellow-Huai River Valleys Winter Wheat Zone(YHWZ)of China during the period of 1964–2015 were evaluated for several lodging-related traits in three cropping seasons.Plant height,height at center of gravity,length of the basal second internode,and lodging index decreased significantly in this period,and the average annual genetic gains for these traits were–0.50 cm or–0.62%,–0.27 cm or–0.60%,–0.06 cm or–0.63%,and–0.01 or–0.94%,respectively.Different from other traits,stem strength showed a significant increasing trend with the breeding period,and the annual genetic gains were 0.03 N or 0.05%.Correlation analysis showed that lodging index was positively correlated with plant height,height at center of gravity,and length of the basal second internode,but negatively correlated with stem strength.Meanwhile,significantly positive correlations were observed between plant height,height at center of gravity,and length of the basal first and second internodes.By comparison with the wild types,dwarfing genes had significant effects on all lodging-related traits studied except for length of the basal first internode and stem strength.Principle component analysis demonstrated that plant height and stem strength were the most important factors influencing lodging resistance.Clustering analysis based on the first two principle components further indicated the targets of wheat lodging-resistant breeding have changed from reducing plant height to strengthening stem strength over the breeding periods.This study indicates that the increase of stem strength is vital to improve lodging resistance in this region under the high-yielding condition when plant height is in an optimal range. 展开更多
关键词 Triticum aestivum lodging resistance STEM strength GENETIC PROGRESS Yellow-Huai River VALLEYS Winter Wheat ZONE
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