淋球菌不同耐药水平中mtrF基因的表达

目的探讨mtrF基因在多重耐药淋球菌中的表达及其与高水平多重耐药淋球菌的关系。方法①纸片扩散法检测58株淋球菌对5种抗生素的敏感性;②试管稀释法测定淋球菌对红霉素的最小抑菌浓度(MIC);③采用RT-PCR技术测定敏感组、低-中等水平多重耐药组及高水平多重耐药组中mtrD、mtrF基因的表达。结果①58株淋球菌中对2种或者2种以上抗生素耐药的有30株,占待测淋球菌的51.7%;②红霉素MIC为敏感、中介、耐药,分别为7株、21株和30株,有17株MIC值≥32.0μg/mL;③高水平多重耐药组mtrF基因表达量升高,与低-中等水平耐药组和敏感组比较,差异均有统计学意义(P<0.01);但后两者之间无明显差异。耐药组mtrD基因表达量升高,与敏感组比较,差异均有统计学意义(P<0.01);但两个耐药组之间无明显差异。结论mtrF基因在高水平多重耐药组中表达均高于敏感组和低-中等水平多重耐药组,表明其在介导淋球菌产生高水平多重耐药过程中可能发挥着十分重要的作用。     

浅谈对我国水运建设项目评估的一点看法

从我国项目评估体系入手，介绍项目评估所遵循的原则、项目评估所包含的内容，分析当前我国水运建设项目评估的现状，提出一些建议。     

THE EXPESSION OF ENDOTHELIN-1 IN VENTRICULAR SPETAL DEFECT WITH PULMONARY HYPER TENSION

Ｔｈｅｖｅｎｔｒｉｃｕｌａｒｓｅｐｔａｌｄｅｆｅｃｔ (ＶＳＤ )ｏｆｃｏｎｇｅｎｉｔａｌｈｅａｒｔｄｉｓｅａｓｅ (ＣＨＤ )ｗｉｔｈ ｐｕｌｍｏｎａｒｙｈｙｐｅｒｔｅｎｓｉｏｎ (ＰＨ )ｉｓａｓｅｒｉｏｕｓｃｏｍｐｌｉｃａｔｉｏｎ ,ｗｈｉｃｈｄｉｒｅｃｔｌｙｉｎｆｌｕｅｎｃｅｓｔｈｅｐｒｏｇｎｏｓｉｓｏｆＣＨＤ ,ｂｕｔｉｔｓｐａｔｈｏｇｅｎｅｓｉｓｔｈａｔｓｔｉｌｌｗａｓｎｏｔｃｌｅａｒ .Ｒｅｃｅｎｔｒｅｓｅａｒｃｈｅｓｒｅｖｅａｌｅｄｔｈａｔｖａｓｃｕｌａｒｅｐｉｔｈｅｌｉｕｍｏｆｐｕｌｍｏｎａｒｙ…     

Synthesis of Novolacs under Microwave Irradiation

Novolacs were successfully synthesized using oxalic acid as the catalyst in a self-designed device based on a domestic microwave oven, The fundamental characteristics of the synthesis of novolacs under microwave irradiation （MI） were investigated, and the properties of the resins polymerized and dehydrated under microwave irradiation and conventional heating （CH） were analyzed comparatively, The results show that MI reduced the polymerization and dehydration time greatly; and that the resins polymedzed and dehydrated under MI presented longer flow distances （ i. e., higher flowability） and shorter cure time than those obtained under CH.     

General precoder design for mitigation of intercarrier interference in OFDM mobile systems

For orthogonal frequency-division multiplexing （OFDM） communication systems, the frequency offset in mobile radio channels distorts the orthogonality between sub-carriers, which results in Intercarrier Interference（ICI） and seriously degrades the performance of systems. Based on ICI coefficients analysis, a novel preceder design scheme is proposed for mitigation of ICI. In this technique, preceder matrix is designed by the way of linear counteraction and inserted in the former transmitter signal. Computer simulation results show that this new scheme can effectively reduce ICI and significantly provide the carrier-interference power ratio improvement. Compared with existing ICI mitigation schemes with channel estimation, the proposed scheme has lower computational complexity, and compared with self- cancellation scheme, the bandwidth efficiency can be improved in this proposed scheme. The proposed scheme also has better convergence stability for time-varying frequency selective fading channel.     

Local Polynomial Estimation of Distribution Functions

Introduction It is always a focus for statisticians to estimateand predict the function and the related informationusing sample data in the situation without knowing thedistribution function. LetX1,X2,…,Xnbe a samplefrom a population with distribution fu…     

Experiment research on two-stage dry-fed entrained flow coal gasifier

The process flow and the main devices of a new two-stage dry-fed coal gasification pilot plant with a throughout of 36 t/d are introduced in this paper. For comparison with the traditional one-stage gasifiers, the influences of the coal feed ratio between two stages on the performance of the gasifier are detailedly studied by a series of experiments. The results reveal that the two-stage gasification decreases the temperature of the syngas at the outlet of the gasifier, simplifies the gasification process, and reduces the size of the syngas cooler. Moreover, the cold gas efficiency of the gasifier can be improved by using the two-stage gasification. In our experiments, the efficiency is about 3 %- 6 % higher than the existing one-stage gasifiers.     

巴尔姆流的模拟与应用

巴尔姆流是交通运输生产与控制过程中普遍存在的一种事件流 ;通过对巴尔姆流的模拟 ,提出了一种将排队服务系统马尔可夫化的方法 ;运用该方法能科学定量地分析排队服务系统的各项运营指标 ;所提出的理论在交通运输生产过程与控制的研究中有广泛的应用价值     

AMA和SRC工况下轻型车催化器温度对比分析

选择了1辆进行轻型车排放控制装置耐久性试验的车辆,在底盘测功机上按照AMA(里程累积循环)和SRC(标准道路循环)工况分别运行,采集了测试车辆的催化器温度和车速数据,研究分析了两种不同耐久工况下的催化器温度分布特征和瞬时变化特征。研究表明:AMA工况下,温度主要分布在460~640℃之间,催化器平均温度为549.34℃;SRC工况下温度分布在两组比较集中的温度区间,31.6%的温度点分布在440~560℃的低温区间,63.5%的温度点分布在600~740℃的高温区间内,平均值为605.4℃,高于AMA工况下平均温度。AMA工况下催化器温度变化呈现高低温反复变化特征,而SRC工况下温度反复变化过程不明显。对于子循环下催化器温度变化,AMA工况呈现出左峰始终小于右峰的规律,SRC工况则取决于催化器温度整体处在上升还是下降阶段。     

上软下硬地层地铁隧道与近接桥梁桩基的相互影响分区研究

依托青岛红岛—胶南城际轨道交通工程侧穿多座桥梁的工程实例,采用有限元强度折减法,对上软下硬地层桩基近接影响下的隧道安全系数变化规律进行研究。结果表明:1)水平方向上,随水平净距增大,隧道安全系数增加,至1倍洞径后,安全系数趋于稳定;2)竖直方向上,随埋深增加,隧道安全系数表现为先增大后减小;3)桩基的存在将降低隧道安全系数,增加隧道达到最大安全系数所需的埋深。通过有无桩基对比,对不同相对位置关系下的地铁隧道近接桥梁施工影响程度进行判定:1)总体上竖向的影响范围和影响程度均大于横向;2)当隧道埋深位于桩底以上时,近接施工几乎只对隧道产生影响;3)当隧道埋深位于桩底以下时,近接施工对于隧道和桥梁桩基均有不同程度的影响,当隧道位于桩底时达到最大。通过样条函数插值补全和多重二次曲面拟合的方法,给出影响系数通用分区图,并结合数值模拟下的桩基受力变形特征,得出影响系数0.8对应的等值线为强影响区与弱影响区的分界线,影响系数1的等值线为弱影响区与无影响区的分界线。通过影响分区结论与监测数据对比,验证了研究成果的实用性。