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宠物犬源沙门氏菌和葡萄球菌耐药性及耐药基因检测 预览
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作者 轩慧勇 林亚军 +2 位作者 高超 吾买尔江·牙合甫 夏利宁 《西北农林科技大学学报:自然科学版》 CSCD 北大核心 2019年第3期14-20,共7页
【目的】了解新疆乌鲁木齐市宠物犬源沙门氏菌和葡萄球菌的耐药性及耐药基因携带情况。【方法】从77份宠物犬直肠粪便样品中分离沙门氏菌和葡萄球菌,采用琼脂稀释法对分离的菌株进行药敏试验,通过PCR方法对沙门氏菌6类23种耐药基因和葡... 【目的】了解新疆乌鲁木齐市宠物犬源沙门氏菌和葡萄球菌的耐药性及耐药基因携带情况。【方法】从77份宠物犬直肠粪便样品中分离沙门氏菌和葡萄球菌,采用琼脂稀释法对分离的菌株进行药敏试验,通过PCR方法对沙门氏菌6类23种耐药基因和葡萄球菌5类9种耐药基因进行检测。【结果】从77份宠物犬粪便样品中分离到沙门氏菌36株,葡萄球菌75株。除头孢噻呋、安普霉素、阿米卡星、硫酸庆大霉素和多黏菌素外,宠物犬源沙门氏菌对其他被捡抗菌药物的耐药率高达97.0%以上,多重耐药以8耐为主,tetB、blaTEM、blaOXA、qnrS、oqxA、oqxB、aac(6′)-Ib-cr、ant(3″)-Ia和floR基因检出率在97.0%以上。宠物犬源葡萄球菌对左氧氟沙星(93.5%)、苯唑西林(90.7%)和氟苯尼考(82.9%)耐药率在80.0%以上,多重耐药集中在4耐、6耐和9耐,主要检出的基因为fexA(40.0%,30/75)和femA(18.7%,14/75),其次为tetM(16.0%,12/75)、ermB(14.7%,11/75)和mecA(1.3%,1/75)。【结论】宠物犬源沙门氏菌和葡萄球菌耐药情况严重,耐药基因携带率高,使宠物犬的细菌性疾病治疗难度加大,应加强耐药菌的监测,降低宠物犬源耐药菌转移给人的潜在风险。 展开更多
关键词 宠物犬 沙门氏菌 葡萄球菌 耐药性 耐药基因检测
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华北地区部分省(市)奶牛乳房炎乳中链球菌耐药表型和耐药基因研究
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作者 田晓英 甄天元 +4 位作者 于忠娜 孙萍 王军 韩荣伟 王世清 《黑龙江畜牧兽医》 CAS 北大核心 2019年第1期1-7,共7页
为了解华北地区4个省(市)奶牛乳房炎乳中链球菌的感染情况及对常用抗生素的耐药性,试验采用EN液体培养基、5%绵羊鲜血琼脂培养基、触酶试验、6.5%NaCl试验、七叶苷试验i马尿酸钠试验和CAMP试验对2016年华北地区240批次乳房炎奶牛乳样进... 为了解华北地区4个省(市)奶牛乳房炎乳中链球菌的感染情况及对常用抗生素的耐药性,试验采用EN液体培养基、5%绵羊鲜血琼脂培养基、触酶试验、6.5%NaCl试验、七叶苷试验i马尿酸钠试验和CAMP试验对2016年华北地区240批次乳房炎奶牛乳样进行链球菌的分离鉴定和分型;采用纸片扩散法对2016年华北地区分离出的链球菌进行药敏试验,对华北地区上下半年及4个省(市)链球菌的药敏情况进行对比;并通过PCR扩增技术研究链球菌的耐药基因,计算链球菌表型耐药率与所携带相关耐药基因的阳性率,比较两者的相符率。结果表明:共分离得到致病性链球菌28株,总分离率为11.67%,其中无乳链球菌7株、停乳链球菌5株和乳房链球菌16株;链球菌分离株对苯唑西林和青霉素G表现出完全耐药;对四环素类药物耐药性较高,强力霉素和四环素的耐药率分别为85.71%和82.14%;对氯霉素类药物高度敏感,敏感率为92.86%;对喹诺酮类和氨基糖苷类药物耐药性较低,平均耐药率分别为8.93%和10.20%;除磺胺类药物外,其他类药物耐药率下半年均低于上半年;在4个省(市)中,天津市链球菌分离株对各类抗生素的平均耐药率高于其他省(市);经PCR扩增检测,耐药基因阳性率在7.14%~26.79%之间,整体检出率较低,耐药基因与耐药表型相符率在0~100%之间,其中氯霉素相符率为0,并不能完全拟合。说明2016年我国华北地区链球菌总检出率较低,乳房链球菌为主要致病菌,链球菌分离株表现出不同程度的耐药性,且多为多重耐药,耐药基因与耐药表型的相符率较低。 展开更多
关键词 奶牛乳房炎 链球菌 分型 抗生素 耐药性 耐药基因
金属铝管影响下磁共振耦合线圈特性参数变化 预览
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作者 王乃健 李长生 +1 位作者 曹娟 缪东辉 《火力与指挥控制》 CSCD 北大核心 2019年第1期23-28,33共7页
为了探究金属物体对磁共振耦合线圈自身特性参数的影响规律,针对现有理论模型不能完全描述金属铝管对线圈特性参数影响规律的问题,构建了金属铝管影响下的磁共振耦合单线圈修正模型,对应开展了仿真与实验研究,并给出了涡电流回路映射电... 为了探究金属物体对磁共振耦合线圈自身特性参数的影响规律,针对现有理论模型不能完全描述金属铝管对线圈特性参数影响规律的问题,构建了金属铝管影响下的磁共振耦合单线圈修正模型,对应开展了仿真与实验研究,并给出了涡电流回路映射电阻R’E和电阻修正量RC具体表达式。研究规律表明:线圈电感参数变化量△L随间隙的增大而减小;线圈电阻参数变化量△R的变化趋势与间隙相关且存在变化趋势分界点,即当铝管与线圈间隙小于10 mm时,线圈电阻参数数值相对放置于空气中是增大的;当铝管与线圈间隙达到15 mm时,线圈电阻参数数值相对放置于空气中是减小的。 展开更多
关键词 金属铝管 磁共振耦合线圈 电阻 电感 电阻修正量
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四川部分区域鸽源沙门菌耐药表型及耐药基因检测
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作者 张跃东 罗薇 +3 位作者 张焕容 任玉鹏 葛润洲 杨劲松 《畜牧与兽医》 北大核心 2019年第2期52-58,共7页
为了解四川省成都市及周边区域鸽源沙门菌的耐药表型及耐药基因携带情况,通过常规细菌分离鉴定并结合PCR方法,获得42株鸽源沙门菌,采用K-B纸片法,选取20种抗生素,对42株鸽源沙门菌进行药敏试验,并结合PCR方法对其耐药基因携带情况进行... 为了解四川省成都市及周边区域鸽源沙门菌的耐药表型及耐药基因携带情况,通过常规细菌分离鉴定并结合PCR方法,获得42株鸽源沙门菌,采用K-B纸片法,选取20种抗生素,对42株鸽源沙门菌进行药敏试验,并结合PCR方法对其耐药基因携带情况进行检测。结果显示:受检菌对链霉素、四环素、多西环素耐药率为88. 1%;对阿莫西林耐药率为83. 3%;对头孢拉定、氨苄西林、萘啶酸的耐药率为81. 0%。42株沙门菌皆有不同程度的多重耐药性,其中33株同时耐4种以上抗生素,占检测菌株的78. 6%(33/42),主要的耐药谱为CTX-CRO-FLO-CPIOFL-AKN。42株沙门菌喹诺酮类耐药基因aac (6’)-Ib-cr检出率最高,为88. 09%(37/32);氨基糖苷类耐药基因aadA1、aph (3)Ⅱ、aac(3)Ⅱ检出率分别为80. 95%(34/42)、76. 19%(32/42)、16. 67%(7/42);β-内酰胺类耐药基因blaTEM-1、bla CMY-2检出率分别为42. 86%(18/42)、19. 04%(8/42);四环素类耐药基因tet M、tet A、tet B检出率分别为40. 4%(17/42)、38. 09%(16/42)、9. 52%(4/42);磺胺类耐药基因sul2检出率为80. 95%(34/42);喹诺酮类耐药基因qnrA检出率为38. 09%(16/42)。结果表明:四川省成都市及周边区域鸽源沙门菌存在普遍耐药,且多重耐药较为严重,耐药基因携带率高。 展开更多
关键词 沙门菌 耐药性 耐药基因 四川
猪链球菌对大环内酯类抗生素的耐药性研究 预览
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作者 蔡田 罗行炜 +5 位作者 徐引第 魏单单 贺丹丹 刘建华 苑丽 胡功政 《河南农业大学学报》 CAS CSCD 北大核心 2019年第1期73-81,共9页
为测定猪链球菌对大环内酯类抗生素的耐药性和相关耐药基因分布特点,分析分离株对大环内酯类抗生素耐药的分子机制。从河南等7省份不同猪场采集来的疑似猪链球菌患病猪的脑脊液、关节液、肝等部位分离、纯化疑似菌落,采用镜检、16SrRNA... 为测定猪链球菌对大环内酯类抗生素的耐药性和相关耐药基因分布特点,分析分离株对大环内酯类抗生素耐药的分子机制。从河南等7省份不同猪场采集来的疑似猪链球菌患病猪的脑脊液、关节液、肝等部位分离、纯化疑似菌落,采用镜检、16SrRNA基因方法鉴定猪链球菌。采用肉汤微量稀释法检测分离猪链球菌对大环内酯类抗生素红霉素、泰乐菌素、替米考星的耐药情况,采用PCR方法检测相关耐药基因(包括编码核糖体甲基化酶的erm基因ermA、ermB、ermC、ermTR和介导外排泵机制的mefA、mefE及msrD基因)分布情况。最终从573份病料分离鉴定出猪链球菌165株,分离率为28.8%。药敏试验结果显示:猪链球菌对大环内酯类抗生素耐药率高达98.1%,对红霉素、泰乐菌素、替米考星耐药率分别达96.9%、95.1%、94.5%,有153株菌株对3种抗生素同时耐药。耐药基因检测发现大环内酯类耐药基因ermA、ermB、ermC、ermTR、mefA、mefE、msrD检出率分别为5.4%、81.8%、13.3%、6.6%、11.5%、7.2%、5.4%,其中ermB检出率最高。除发现有93株菌株仅携带1个耐药基因外,分别有30、17、2、1个菌株分别携带2、3、4、6个大环内酯类耐药基因。在检出耐药基因的菌株中有82.5%(118/143)的菌株仅携带erm基因,有13.9%(20/143)的菌株同时携带erm以及mef、msr基因,另有3%(5/143)的菌株仅携mef、msr基因。猪链球菌对大环内酯类药物广泛耐药,大环内酯类耐药基因在猪链球菌中广泛分布,细菌的耐药性和菌株耐药基因携带情况基本呈正相关。以ermB介导的核糖体23SrRNA甲基化耐药机制占主导地位,由mefA、mefE、msrD介导的外排泵机制亦存在于分离菌株中。 展开更多
关键词 猪链球菌 大环内酯类 耐药性 耐药机制
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Patrinia scabiosaefolia Inhibits Growth of 5-FU-Resistant Colorectal Carcinoma Cells via Induction of Apoptosis and Suppression of AKT Pathway
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作者 HUANG Si-zhou LIU Wang-yu +3 位作者 HUANG Yue SHEN A-ling LIU Li-ya PENG Jun 《中国结合医学杂志:英文版》 SCIE CAS CSCD 2019年第2期116-121,共6页
Objective: To investigate the effects of ethanol extract of Patrinia scabiosaefolia(EEPS) on chemo-resistance of colorectal cancer cells(CRC) and explore the possible molecular mechanisms. Methods: 5-fluorouracil(5-FU... Objective: To investigate the effects of ethanol extract of Patrinia scabiosaefolia(EEPS) on chemo-resistance of colorectal cancer cells(CRC) and explore the possible molecular mechanisms. Methods: 5-fluorouracil(5-FU)-resistant human colorectal carcinoma cell line(HCT-8/5-FU) and its parental cells HCT-8 were treated with EEPS(0, 0.25, 0.50, 1 or 2 mg/mL), or 5-FU(0, 100, 200, 400, 800 or 1600 μmol/L). The 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide(MTT) assay was performed to evaluate the cell viability. Cell density was observed by phase-contrast microscope, cell counting and colony formation assay were used to determine the cell proliferation of HCT-8/5-FU cells treated with 0, 0.5, 1 or 2 mg/mL EEPS. Cell apoptosis was determined by Hoechst staining. Western-blot was performed to detect the phosphorylation of AKT as well as the protein expression level of B-cell CLL/lymphoma 2(Bcl-2) and Bcl-2-associated X protein(Bax). Results: Compared with HCT-8 cells, MTT assay results indicated that HCT-8/5-FU cells were resistant to 5-FU treatment(P<0.05), and sensitive to EEPS treatment(P>0.05). Moreover, compared with untreated HCT-8/5-FU cells, 1 and 2 mg/mL of EEPS treatment significantly reduced cell density, cell number, inhibited cell survival(P<0.05), and induced apoptosis in HCT-8/5-FU cells. Furthermore, 1 and 2 mg/mL of EEPS significantly decreased the phosphorylation level of p-AKT and Bcl-2 protein expression, and increased the expression of Bax protein(P<0.05). Conclusion: EEPS is a promising therapeutic agent that may overcome chemo-resistance in cancer cells, likely through suppression of the AKT pathway and promotion of cancer cell apoptosis. 展开更多
关键词 AKT PATHWAY COLORECTAL cancer 5-FLUOROURACIL resistance Patrinia scabiosaefolia Chinese medicine
Strength and Wear Behavior of Mg Alloy AE42 Reinforced with Carbon Short Fibers
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作者 Sabbah Ataya Naser A.Alsaleh Mohamed M.El-Sayed Seleman 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第1期31-40,共10页
In addition to the advantage of the lightweight of magnesium alloys, magnesium composites have moderate strength and elastic modulus. The proposed application of magnesium composites as diesel truck pistons makes it n... In addition to the advantage of the lightweight of magnesium alloys, magnesium composites have moderate strength and elastic modulus. The proposed application of magnesium composites as diesel truck pistons makes it necessary to assess their wear performance. Little research data have been discussed on wear behavior of Mg alloy AE42 matrix and its composites. Thus, this paper reports wear behavior of magnesium alloy AE42(Mg–Al–Mn—RE;rare earth) and its composite AE42-C, which contains 23 vol% of randomly oriented carbon short fibers. Materials characterization, including density measurements, hardness testing, microstructures investigation, and compression testing at temperatures of 25, 150,and 300 °C, were conducted. Wear tests were performed under various loads and sliding distances. Wear mechanisms were also proposed based on the examination of worn surfaces using optical microscopy and scanning electron microscopy equipped with EDX(energy-dispersive X-ray spectrometry) analysis system. The hardness of AE42-23 vol% C composite is twice the hardness of the Mg matrix alloy AE42. Significant improvements to yield stress and compressive strength at temperatures of 25, 150, and 300 °C of the composite versus the AE42 alloy are achieved. Wear resistance of the composite is improved considerably versus that of the Mg alloy AE42 at the various sliding distances. Smearing of graphite on the worn surface produces a lubricating film that delays change from mild to severe wear of the composite, especially at high loads. EDX analysis of the worn surface shows oxidation of the matrix alloy at higher wear loads, and this mechanism decreases in the presence of carbon fibers under the same loads. Abrasive wear, oxidation, and plastic deformation are the dominant wear mechanisms for the alloy matrix AE42, whereas mainly abrasive wear is the wear mechanism of AE42-23 vol% C composite under the proposed testing conditions. 展开更多
关键词 Magnesium composites CARBON short fibers COMPRESSIVE STRENGTH WEAR resistance WEAR mechanisms
不同菌属的氟苯尼考耐药特点及floR基因的序列分析 预览
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作者 吴方达 《中国农学通报》 2019年第2期122-126,共5页
为了解福建宁德地区猪源细菌对氟苯尼考耐药性及耐药基因floR的遗传特性。本研究从宁德地区6个猪场分别采集了50份仔猪粪便样品。从中分离得到氟苯尼考耐药大肠杆菌17株、沙门氏菌2株、肺炎克雷伯菌5株和鲍曼不动杆菌8株。并对其耐药基... 为了解福建宁德地区猪源细菌对氟苯尼考耐药性及耐药基因floR的遗传特性。本研究从宁德地区6个猪场分别采集了50份仔猪粪便样品。从中分离得到氟苯尼考耐药大肠杆菌17株、沙门氏菌2株、肺炎克雷伯菌5株和鲍曼不动杆菌8株。并对其耐药基因floR进行同源性分析。结果显示:宁德地区猪源大肠杆菌、沙门氏菌、肺炎克雷伯菌和鲍曼不动杆菌对氟苯尼考的耐药检出率分别为34%、4%、10%和16%。且所有的分离细菌都呈现了多重耐药性。同源性分析发现不同细菌间的耐药基因floR存在高度同源性。这些结果表明氟苯尼考耐药基因floR广泛存在于不同细菌间,且可在不同细菌间进行水平传播。该研究为氟苯尼考耐药基因floR的广泛传播奠定了一定的理论基础,对临床合理用药提供了依据。 展开更多
关键词 氟苯尼考 耐药性 floR基因 猪源细菌
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冠心病监护病房住院患者感染病原菌种类及耐药性分析 预览
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作者 邱浩 王延政 刘妍妍 《世界最新医学信息文摘(电子版)》 2019年第6期28-29,31共3页
目的探讨冠心病监护病房(CCU)住院患者感染的病原菌种类及耐药情况,为抗菌药物临床正确应用提供参考。方法采用VITEK-32全自动微生物分析仪对CCU送检的患者标本进行病原学检测和药敏试验。结果 356份标本中共检出163株病原菌,分离率为45... 目的探讨冠心病监护病房(CCU)住院患者感染的病原菌种类及耐药情况,为抗菌药物临床正确应用提供参考。方法采用VITEK-32全自动微生物分析仪对CCU送检的患者标本进行病原学检测和药敏试验。结果 356份标本中共检出163株病原菌,分离率为45.8%;其中有46株革兰阳性球菌(占28.22%);117株革兰阴性杆菌(占71.78%)。肺炎链球菌(13.5%),金黄色葡萄球菌(9.82%),凝固酶阴性葡萄球菌(4.9%)是革兰阳性球菌中常见的致病菌;鲍曼不动杆菌(26.38%),铜绿假单胞菌(19.02%),肺炎克雷伯菌(11.66%),大肠埃希菌(8.59%),流感嗜血杆菌(6.13%)为革兰阴性菌中常见的致病菌。不同的病原菌有其自身的耐药特点,革兰阳性球菌中的肺炎链球菌、金黄色葡萄球菌和凝固酶阴性葡萄球菌耐药率较高,对青霉素、红霉素和克林霉素的耐药率均达60%以上;肺炎链球菌对苯唑西林、美罗培南、亚胺培南、氧氟沙星、左氧氟沙星、莫西沙星有较低的耐药率(小于20%);目前没有发现耐万古霉素和耐利奈唑胺菌株。鲍曼不动杆菌对氨苄西林和头孢替坦的耐药率分别高达95.35%和93.02%;铜绿假单胞菌对氨苄西林舒巴坦和复方新诺明的耐药率分别为100.00%和96.77%。革兰阴性杆菌中耐药率较低的为亚胺培南、阿米卡星和含酶抑制剂类抗菌药物如哌拉西林他唑巴坦、头孢哌酮舒巴坦。结论由于长期广泛应用抗菌药物,导致常见病原菌对多种抗菌药物的耐药性发生变化,临床医生在使用抗菌药物前应先进行细菌培养,根据药敏试验结果,正确合理应用抗菌药物。 展开更多
关键词 冠心病监护病房 病原菌 耐药性
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ALK抑制剂治疗非小细胞肺癌的研究进展
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作者 谷瑞雪 邢影 蔡莉 《中国肿瘤》 CAS CSCD 北大核心 2019年第2期126-131,共6页
肺癌是最常见的恶性肿瘤之一,且为全世界范围内肿瘤相关性死亡的首要原因,其中非小细胞肺癌(non-small cell lung cancer,NSCLC)约占肺癌总数的85%,预后较差。间变性淋巴瘤激酶(anaplastic lymphoma kinase,ALK)融合基因为促进肺癌进展... 肺癌是最常见的恶性肿瘤之一,且为全世界范围内肿瘤相关性死亡的首要原因,其中非小细胞肺癌(non-small cell lung cancer,NSCLC)约占肺癌总数的85%,预后较差。间变性淋巴瘤激酶(anaplastic lymphoma kinase,ALK)融合基因为促进肺癌进展的一个驱动基因,约2%~8%的NSCLC患者具有ALK融合基因,其对NSCLC的发生和发展至关重要。近年来靶向ALK融合基因已成为NSCLC治疗的前沿手段,第一、二、三代ALK酪氨酸激酶抑制剂(ALK-tyrosine kinase inhibitors,ALK-TKIs)治疗ALK阳性的NSCLC显示出较好的疗效,但仅在一定时间内对特定人群有效。因此规范应用ALK-TKIs、探讨耐药机制及应对不良反应等是临床面临的难题。本文关于这些问题的研究进展作一综述。 展开更多
关键词 肺肿瘤 ALK抑制剂 耐药
Anisotropy in mechanical properties and corrosion resistance of 316L stainless steel fabricated by selective laser melting 预览
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作者 Xiao-qing Ni De-cheng Kong +5 位作者 Ying Wen Liang Zhang Wen-heng Wu Bei-bei He Lin Lu De-xiang Zhu 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第3期319-328,共10页
The corrosion behavior and mechanical properties of 316L stainless steel (SS) fabricated via selective laser melting (SLM) were clarified by potentiodynamic polarization measurements, immersion tests, and tensile expe... The corrosion behavior and mechanical properties of 316L stainless steel (SS) fabricated via selective laser melting (SLM) were clarified by potentiodynamic polarization measurements, immersion tests, and tensile experiments. The microstructural anisotropy of SLMed 316L SS was also investigated by electron back-scattered diffraction and transmission electron microscopy. The grain sizes of the SLMed 316L SS in the XOZ plane were smaller than those of the SLMed 316L SS in the XOY plane, and a greater number of low-angle boundaries were present in the XOY plane, resulting in lower elongation for the XOY plane than for the XOZ plane. The SLMed 316L was expected to exhibit higher strength but lower ductility than the wrought 316L, which was attributed to the high density of dislocations. The pitting potentials of the SLMed 316L samples were universally higher than those of the wrought sample in chloride solutions because of the annihilation of MnS or (Ca,Al)-oxides during the rapid solidification. However, the molten pool boundaries preferentially dissolved in aggressive solutions and the damage of the SLMed 316L in FeCl3 solution was more serious after long-term service, indicating poor durability. 展开更多
关键词 selective laser MELTING mechanical property corrosion resistance 316L STAINLESS steel ANISOTROPY MOLTEN POOL boundary
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Corrosion behavior of Ni-based coating containing spherical tungsten carbides in hydrochloric acid solution
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作者 Shan-shan Liu Hai-yan Chen +3 位作者 Xuan Zhao Li Fan Xiao-ming Guo Yan-sheng Yin 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2019年第2期191-199,共9页
A Ni-based alloy coating with 30 wt.%spherical fungsten carbide particles was prepared through plasma transferred arc welding on 42CrMo steel.The composition and microstructure of the coati ng were examined through X-... A Ni-based alloy coating with 30 wt.%spherical fungsten carbide particles was prepared through plasma transferred arc welding on 42CrMo steel.The composition and microstructure of the coati ng were examined through X-ray diffraction and scanning electron microscopy with energy-dispersive spectrometry.The corrosion behaviors of the coating compared to the Ni coating without tungsten carbide particles and to the bare substrate in a0.5 mol/L HC1 solution were presented through polarization curves,electrochemical impedance spectroscopy(EIS)measurements and long-term immersion tests.The results demonstrated that the composite coating microstructure comprised Ni matrix,Ni-rich phase,tungsten carbide particles,W-rich phase and Cr-rich phase.The polarization curves and EIS measurements presented that a passivation film,which mainly included Ni,Cr,Fe and W oxides,was formed in the composite coating that protected the substrate from corrosion by HC1 solution.In the immersion tests,a micro-galvanic reaction at the new-formed phases and Ni matrix interface caused severe pit corrosion and Ni matrix consumption.The debonding of Ni-rich and W-rich phases could be observed with the immersion time extension.The tungsten carbide particles and Cr-rich phase were still attached on the surface for up to 30 days. 展开更多
关键词 Plasma TRANSFERRED welding SPHERICAL TUNGSTEN CARBIDE NI-BASED coating Corrosion resistance Electrochemical impedanee spectroscopy
酵母菌对重金属的吸附与抗性和解毒重金属的胞内分子机制研究进展 预览
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作者 李丽杰 贺敏 +1 位作者 贺银凤 孙禹 《食品科学》 EI CAS CSCD 北大核心 2019年第3期330-337,共8页
利用有益的酵母菌去除食品基质、动物及人体的重金属污染是近年的研究热点。本文概述了多种酵母菌吸附及抗重金属的情况,并对酵母菌在重金属胁迫下的胞内解毒机制进行分析,包括谷胱甘肽合成的解毒机制、与酵母菌解毒重金属相关的基因和... 利用有益的酵母菌去除食品基质、动物及人体的重金属污染是近年的研究热点。本文概述了多种酵母菌吸附及抗重金属的情况,并对酵母菌在重金属胁迫下的胞内解毒机制进行分析,包括谷胱甘肽合成的解毒机制、与酵母菌解毒重金属相关的基因和蛋白、转运蛋白介导的细胞内重金属的排出和液泡隔离机制及金属硫蛋白和植物螯合肽对重金属的螯合作用,重点从分子角度分析了酵母菌对重金属的解毒机制,归纳了解毒过程中关键性的基因和蛋白质以及它们的功能作用,旨在为酵母菌作为生物吸附剂应用于生态环境、被重金属污染的发酵食品及动物和人体提供依据。 展开更多
关键词 酵母菌 重金属 生物吸附 抗性 解毒机制
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Enhanced elevated temperature wear resistance of Al-17Si-5Cu alloy after a novel short duration heat treatment 预览
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作者 Biplab Hazra Supriya Bera Bijay Kumar Show 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第3期360-368,共9页
The goal of the present study is to improve the elevated temperature wear resistance of an Al-17 wt%Si-5 wt%Cu alloy(AR alloy) by a novel short duration heat treatment process. The elevated temperature(100°C) dry... The goal of the present study is to improve the elevated temperature wear resistance of an Al-17 wt%Si-5 wt%Cu alloy(AR alloy) by a novel short duration heat treatment process. The elevated temperature(100°C) dry sliding wear behavior of an AR alloy was studied after microstructural modification using the proposed heat treatment. The study revealed considerable microstructural modifications after the heat treatment and the heat treated alloy was designated as HT(heat treatment) alloy. A higher hardness value was obtained for the HT alloy compared to the AR alloy. Accordingly, the wear rate for the HT alloy was found to be significantly lower compared to the as-cast AR alloy at all applied loads. Accelerated particle pull-out for the AR alloy at elevated temperatures resulted in poor wear behavior for it compared to the HT alloy. On the other hand, the Si particles remained intact on the worn surface of the HT alloy due to the good particle/matrix bonding that resulted from the isothermal heat treatment. Furthermore, the age hardening that occurred in the HT alloy during wear provided additional wear resistance. Thus, the HT alloy at 100°C exhibited a lower wear rate compared to the AR alloy even at room temperature for all applied loads. This improvement was attributed to microstructural modification upon isothermal heat treatment along with the age hardening effect. 展开更多
关键词 AL-SI alloys ISOTHERMAL heat treatment wear resistance MICROSTRUCTURAL investigation
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一株鸡大肠杆菌的分离鉴定与耐药性研究
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作者 江林宜 《中国动物传染病学报》 CAS 北大核心 2019年第1期100-103,共4页
无菌采集病死鸡的肝脏、肾脏、脾脏、肺脏等组织,接种于麦康凯平板和普通琼脂,进行细菌分离与培养,并对分离菌进行生化试验和16s rDNA基因序列分析,同时用14种抗菌药物对分离菌株进行药敏试验。结果显示,分离菌在麦康凯平板上呈红色圆... 无菌采集病死鸡的肝脏、肾脏、脾脏、肺脏等组织,接种于麦康凯平板和普通琼脂,进行细菌分离与培养,并对分离菌进行生化试验和16s rDNA基因序列分析,同时用14种抗菌药物对分离菌株进行药敏试验。结果显示,分离菌在麦康凯平板上呈红色圆形菌落;镜检结果为革兰氏阴性杆菌;分离菌株能够发酵葡萄糖、棉籽糖、乳糖、木糖等糖类并产酸产气,鸟氨酸及赖氨酸试验阳性,苯丙氨酸脱氨酶及硫化氢阴性,符合大肠杆菌的生化特性;16s rDNA基因序列测定结果显示分离菌株为大肠杆菌;分离菌株对菌必治、美洛西林、恩诺沙星、诺氟沙星的敏感率较高,而对萘啶酸、青霉素等耐药。本研究为鸡大肠杆菌的诊断和防治提供了依据。 展开更多
关键词 大肠杆菌 耐药性 分离 鉴定
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体外冲击波碎石机的常见故障及解决方法
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作者 田洁 《医疗装备》 2019年第1期155-156,共2页
体外冲击波碎石机治疗尿路结石患者创伤小、费用低、效果显著,广泛应用于临床。为了确保医院碎石机安全使用,延长使用寿命,提高开机率,本研究在阐述碎石机的原理,冲击波部分电路工作原理的基础上,分析了3种常见故障,并提出解决方法。最... 体外冲击波碎石机治疗尿路结石患者创伤小、费用低、效果显著,广泛应用于临床。为了确保医院碎石机安全使用,延长使用寿命,提高开机率,本研究在阐述碎石机的原理,冲击波部分电路工作原理的基础上,分析了3种常见故障,并提出解决方法。最后本研究结合碎石机使用过程中的故障检修和平时维护保养情况,归纳总结了一些设备维护的注意事项供设备工程师参考,以更好地保障临床科室碎石机的正常运行,保障患者和操作人员的人身安全。 展开更多
关键词 碎石机 变压器 电阻 冲击波
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呼吸与危重症医学科鲍曼不动杆菌感染情况及耐药性分析 预览
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作者 黄艳 朱光发 +2 位作者 武元星 刘玉磊 吴春婷 《临床肺科杂志》 2019年第1期37-41,共5页
目的分析北京安贞医院呼吸与危重症医学科鲍曼不动杆菌感染情况及耐药性变迁。方法回顾性分析2005年1月-2016年12月北京安贞医院呼吸与危重症医学科住院患者感染的鲍曼不动杆菌感染以及耐药性等情况,分三个阶段(Ⅰ阶段为2005-2008年,Ⅱ... 目的分析北京安贞医院呼吸与危重症医学科鲍曼不动杆菌感染情况及耐药性变迁。方法回顾性分析2005年1月-2016年12月北京安贞医院呼吸与危重症医学科住院患者感染的鲍曼不动杆菌感染以及耐药性等情况,分三个阶段(Ⅰ阶段为2005-2008年,Ⅱ阶段为2009-2012年,Ⅲ阶段为2013-2016年)进行分析。结果2005-2016年共分离出鲍曼不动杆菌1382株,其中Ⅰ、Ⅱ、Ⅲ阶段分别为206、496、680株。鲍曼不动杆菌在标本中的分布以呼吸道分泌物为主,达98.22%,其次血液为1.37%,尿液为1.30%。在药敏结果中,鲍曼不动杆菌对替加环素耐药率最低为1.35%。在Ⅰ、Ⅱ、Ⅲ阶段,鲍曼不动杆菌对头孢哌酮/舒巴坦的耐药率较低,分别为26.00%、15.08%、25.73%;对亚胺培南的耐药率分别为27.18%、84.01%、83.04%,对美罗培南耐药率分别为51.52%、83.49%、77.62%。在Ⅲ阶段,鲍曼不动杆菌对左氧氟沙星的耐药率为60.86%,对哌拉西林/他唑巴坦、环丙沙星、头孢他啶及头孢曲松的耐药率均在80%以上。结论鲍曼不动杆菌对多种抗菌药物呈严重耐药,治疗困难。临床需通过加强细菌的耐药性监测,根据药敏试验结果合理选择抗菌药物,并加强院感管理等措施,有效控制耐药菌株的流行及医院感染。 展开更多
关键词 鲍曼不动杆菌 耐药性 呼吸与危重症
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Synthesis and AO Resistant Properties of Novel Polyimide Fibers Containing Phenylphosphine Oxide Groups in Main Chain
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作者 Yong Zhao Hong Gao +4 位作者 Guo-Min Li Fang-Fang Liu Xue-Min Dai Zhi-Xin Dong Xue-Peng Qiu 《高分子科学:英文版》 SCIE CAS CSCD 2019年第1期59-67,共9页
A series of co-polyimide(PI)fibers containing phenylphosphine oxide(PPO)group were synthesized by incorporating the bis(4-aminophenoxy)phenyl phosphine oxide(DAPOPPO)monomer into the PI molecular chain followed by dry... A series of co-polyimide(PI)fibers containing phenylphosphine oxide(PPO)group were synthesized by incorporating the bis(4-aminophenoxy)phenyl phosphine oxide(DAPOPPO)monomer into the PI molecular chain followed by dry-jet wet spinning.The effects of DAPOPPO molar content o n the atomic oxygen(AO)resistance of the fibers were investigated systematically.When the AO fluence increased from 0 atoms cm^-2 to 3.2×l0^20 atoms.cm^-2,the mass loss of the fibers showed the dependence on DAPOPPO molar content in co-PI fibers.The PI fiber containing 40%DAPOPPO showed lower mass loss compared to those containing 0%and 20%DAPOPPO.At higher AO fluence,the higher DAPOPPO content gave rise to dense carpet-like surface of fibers.XPS results indicated that the passivated phosphate layer was deposited on the fiber surface when exposed to AO,which effectively prevented fiber from AO erosion.With the DAPOPPO content increasing from 0%to 40%,the retentions of tensile strength and initial modul us for the fibers exhibited obvious growth from 44%to 68%,and 59%to 70%,after A O exposure with the fluence of 3.2×l0^20 atoms cm^-2.T h e excellent AO resistance benefits the fibers for application in low Earth orbit as flexible construction components. 展开更多
关键词 POLYIMIDE fibers Bis(4-aminophenoxy)phenyl PHOSPHINE oxide(DAPOPPO) Dry-jet wet SPINNING AO resistance
Study on Frost Prevention and Drought Resistance Effect of Potato under Different Planting Methods 预览
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作者 Sun Jun Chen Yongxu +2 位作者 Guo Junwei Li Shuxia Yang Meilan 《气象与环境研究:英文版》 CAS 2019年第1期76-80,共5页
According to different planting test data, meteorological data, field planting survey and expert interview data in recent years, frost prevention and drought resistance effect of potato under different planting method... According to different planting test data, meteorological data, field planting survey and expert interview data in recent years, frost prevention and drought resistance effect of potato under different planting methods were studied using agro-meteorological disaster risk index analysis method. The results showed that the risk index of potato with the full-film planting was small due to good thermal insulation and soil moisture conservation performance. The risk index of potato with half-film planting (flat mulching, ridging planting and furrow planting) was moderate, while that of ridge tillage without mulching, double rows, full of stars and flat planting was large, and their frost prevention and drought resistance effect were poor. It provides support and reference for understanding the frost and drought conditions of potatoes under different planting methods and carrying out insurance weather services for farmers and production managers. 展开更多
关键词 POTATO Plastic film covering FROST PREVENTION DROUGHT resistance METEOROLOGICAL disaster risk index
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3种常用杀虫剂对不同植物上南方小花蝽的毒力测定 预览
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作者 李宜儒 胡昌雄 +2 位作者 段盼 陈国华 张晓明 《河南农业科学》 北大核心 2019年第2期98-104,共7页
为了探明杀虫剂对蓟马类害虫主要天敌昆虫南方小花蝽的影响,选取吡虫啉、高效氟氯氰菊酯和阿维菌素3种常用于防治蓟马的杀虫剂,采用触杀方法对昆明地区3种植物上的南方小花蝽成虫和若虫进行毒力测定。结果表明,南方小花蝽成虫和若虫均... 为了探明杀虫剂对蓟马类害虫主要天敌昆虫南方小花蝽的影响,选取吡虫啉、高效氟氯氰菊酯和阿维菌素3种常用于防治蓟马的杀虫剂,采用触杀方法对昆明地区3种植物上的南方小花蝽成虫和若虫进行毒力测定。结果表明,南方小花蝽成虫和若虫均对高效氟氯氰菊酯的敏感度最高,不同植物上成虫的24hLC50值为木香0.577mg/L、辣椒0.695mg/L、锦绣杜鹃0.610mg/L,若虫的24hLC50值为木香1.855mg/L、辣椒3.385mg/L、锦绣杜鹃2.089mg/L;对吡虫啉的敏感度最低,不同植物上成虫的24hLC50值为木香8.024mg/L、辣椒20.183mg/L、锦绣杜鹃8.900mg/L,若虫的24hLC50值为木香10.297mg/L、辣椒22.607mg/L、锦绣杜鹃10.338mg/L。南方小花蝽若虫对杀虫剂的敏感度低于成虫,且取食不同植物上蓟马种群的南方小花蝽对同一种杀虫剂表现出不同的敏感性。南方小花蝽对烟碱类杀虫剂吡虫啉的敏感性较低,应是蓟马类害虫防治中优先选择的杀虫剂,建议在田间使用杀虫剂防治蓟马时尽量避开南方小花蝽种群成虫发生高峰期,以达到保护天敌的目的。 展开更多
关键词 杀虫剂 南方小花蝽 蓟马 毒力测定 抗性
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