ZrO2/Al2O3复合载体镍基催化剂CO甲烷化反应本征动力学

采用固定床反应器,研究了复合载体镍基催化剂上的CO甲烷化反应。在温度为250～440℃,压力为0.1～2.5 MPa,原料气配比（n_H2/n_CO）为1.0～4.5的情况下,考察了操作条件对复合载体镍基催化剂甲烷化反应的影响。实验结果表明：CO转化率、CH₄的选择性均随着反应温度、反应压力的升高而增加;当反应温度达到340℃时,CO转化率最高;当n_H2/n_CO=3.0时,具有较高的CO转化率和CH₄的选择性。通过正交法设计实验,测定了甲烷化反应动力学数据。以双曲型动力学方程建立了以各组分逸度表示的CH₄和CO₂反应动力学模型,并用最大继承法对参数进行估值,获得动力学参数。残差分析及统计检验表明动力学模型是适宜的。     

CO2激光照射心包经穴位对冠心病Ⅱ段导联心电图ST的即刻影响

目的 观察CO2激光照射心包经穴位对冠心病Ⅱ导联心电图的影响.方法 将30例冠心病Ⅱ导联心电图ST段下移的患者分成3组,分别给予CO2激光照射、针刺、CO2激光照射加针刺刺激心包经穴位,比较其心电图的变化.结果 3组治疗20min后,ST段均出现即刻改变,出现率针刺组为94.7%,CO2激光组为87.5%、CO2激光加...     

乳香提取物对HL-60细胞株VEGF分泌及其Flt-1受体表达的影响

目的:探索不同浓度乳香提取物作用于HL-60细胞后,白血病细胞株HL-60细胞VEGF mRNA表达及VEGF蛋白分泌及受体Flt-1的变化.方法:MTT法检测乳香提取物对细胞增殖的抑制作用,选择适当的药物浓度及作用时间:RT-PCR法检测乳香提取物处理前后HL-60细胞中VEGF mRNA表达水平;Western B...     

腹腔镜与后腹腔镜CO2气腹对患者血流动力学及CO2排除量的影响

目的:探讨经腹腔和经腹膜后腔入路手术CO2气腹对患者血流动力学及CO2排除量的影响。方法:选择经腹膜后腔(A组)和经腹腔(B组)入路手术患者各35例,监测气腹前、气腹后30min、60min和气腹结束后30min血流动力学和动脉血气以及不同时段机体对CO2的排除量。结果:两组患者组内气腹后30min、60min患者心率(HR)、平均动脉压(MAP)、中心静脉压(CVP)均较气腹前差异显著,有统计学意义(P<0.05),组间比较无统计学意义(P>0.05)。两组患者组内气腹后30 min、60min患者动脉血二氧化碳分压(PaCO2)和CO2排除量较气腹前明显增加,pH明显下降(P<0.05)。且A组在60min明显高于B组(P<0.05)。结论:经腹膜后腔入路手术CO2气腹对患者血流动力学和动脉血气的影响更大,后腹腔镜手术更容易引起高碳酸血症,术中需加强呼吸管理和内环境监测。     

腹腔镜手术室CO2浓度对医护人员健康的影响

目的探讨腹腔镜手术室内CO2浓度对医护人员健康的影响.方法本研究将60名手术室护士随机分为开腹手术组和腔镜手术组,分别于术前及术后对2组人员测量生命体征、检测动脉血气、评价疲倦程度,并采用便携式红外线CO2分析仪检测手术室内不同时刻CO2浓度.结果腔镜手术室内CO2浓度于手术30 min时升高,术中维持较高水平,于手术结束时达最高值;与本组术前和开腹手术组相比,腔镜手术组人员手术后心率和呼吸频率明显增快,p H降低,PCO2升高,且疲倦严重度评分显著增加(P<0.05).结论腔镜手术造成手术室内CO2污染,危害医护人员身心健康,应予以重视.     

A literature review: the cardiovascular effects of exposure to extremely low frequency electromagnetic fields

The effects of exposure to extremely low frequency (ELF) electromagnetic fields (EMFs) on human cardiovascular parameters remain undetermined. Epidemiological studies have utilized dosimetry estimations of employee workplace exposure using altered heart rate variability (HRV) as predictive of certain cardiovascular pathologies. Laboratory studies have focused on macrocirculatory indicators including heart rate, HRV and blood pressure. Few studies have been conducted on the response of the microcirculatory system to EMF exposure. Attempts to replicate both epidemiological and laboratory studies have been mostly unsuccessful as study design, small sample populations and confounding variables have hampered progress to date. Identification of these problems, in the current context of international exposure guideline re-evaluation, is essential for future EMF studies. These studies should address the possible deleterious health effects of EMFs as well as the detection and characterization of subtle physiological changes they may induce. Recommendations for future work include investigating the macro- and microcirculatory relationship and the use of laboratory geomagnetic shielding.     

p53和Bcl-2 mRNA表达在三七皂苷R1诱导HL-60细胞凋亡中的作用

目的：探讨三七皂苷R1诱导HL-60细胞凋亡的作用机制.方法：采用MTT比色法观察三七皂苷R1对人白血病细胞株HL-60细胞增殖的抑制作用.采用流式细胞术检测细胞凋亡改变,并以RT-PCR检测凋亡调节基因p53、Bcl-2的表达.结果：三七皂苷R1能明显抑制人白血病细胞株HL-60细胞的生长,且呈时间和浓度依赖性.三七皂苷R1作用后人白血病细胞株HL-60细胞呈现凋亡特征,流式细胞术显示凋亡细胞比例升高.RT-PCR检测可见p53 mRNA表达显著增加,而Bcl-2 mRNA表达减少.结论：三七皂苷R1能诱导人白血病细胞株HL-60细胞凋亡,其作用可能与凋亡调节基因p53的上调和Bcl-2的下调有关.     

CO Oxidation over Pd Catalyst Supported on Porous TiO2 Prepared by Plasma Electrolytic Oxidation (PEO) of a Ti Metallic Carrier

A porous TiO₂ layer was prepared with the plasma electrolytic oxidation (PEO) of Ti. In a further step, Pd was deposited on the TiO₂ surface layer using the adsorption method. The activity of the Pd/TiO₂/Ti catalyst was investigated during the oxidation of CO to CO₂ in a mixture of air with 5% CO. The structure of the catalytic active layer was studied using a scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), inductively coupled plasma mass spectrometry (ICP-MS), and X-ray diffraction (XRD). The PEO process provided a porous TiO₂ layer with a uniform thickness in the range of 5–10 µm, which is desirable for the production of Pd-supported catalysts. A TOF-SIMS analysis showed the formation of Pd nanoparticles after the adsorption treatment. The conversion of CO to CO₂ in all samples was achieved at 150–280 °C, depending on the concentration of Pd. The composition of Pd/ TiO₂/Ti was determined using ICP-MS. The optimum concentration of Pd on the surface of the catalyst was approximately 0.14% wt. This concentration was obtained when a 0.4% PdCl₂ solution was used in the adsorption process. Increasing the concentration of PdCl₂ did not lead to a further improvement in the activity of Pd/ TiO₂/Ti.     

Local Electrochemical Corrosion Properties of a Nano-SiO2/MAO Composite Coating on an AM60B-Mg Alloy

In order to improve the corrosion resistance of the automotive AM60B-Mg alloy, a nano-SiO₂/MAO composite coating was prepared on the surface of the alloy. The electrochemical properties were studied in an 80 °C corrosion environment using potentiodynamic polarization tests. Local Electrochemical Impedance Spectroscopy (LEIS) was used to study the corrosion mechanisms of coating defect zone. The microstructure and phase of the samples were observed by confocal laser microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Macroscopic electrochemical test results showed that the impedance of the nano-SiO₂/MAO coating was much higher than that of the MAO coating, by about 433 times. Local electrochemical test results showed that the minimum impedance of the nano-SiO₂/MAO coating was 1–2 orders of magnitude higher than the maximum impedance of the MAO coating. The defective SiO₂/MAO coating still had high corrosion resistance compared to the defective MAO coating. A physical model of local corrosion mechanisms was proposed.     

昆明部分工厂男性吸烟者体内CO及COHb水平与吸烟量的关系分析

[目的]通过对吸烟人员体内CO、COHb含量的测定,分析和了解吸烟者体内COHb水平,作为评价吸烟对人体健康危害的参考指标.[方法]采用美国生产的Micro 4 Smokelyzer型CO测定仪测定CO和COHb,CO和CO-Hb的含量由仪器自动生成.[结果]每日吸烟10-20支,20支以上以及烟龄10年以上者COHb含量分别为2.36,2.85和2.27,超出正常值;经过中位数检验,除每日吸烟20支以上组与10～20支两组间CO和COHb%含量差异无统计学意义(P>0.05)外,其余各组差异均有统计学意义(P<0.05).[结论]每日吸烟10支以上或吸烟烟龄10年以上人群不论是COHb含量还是呼出气CO含量均超过正常值;并且随着每日吸烟量的增加以及吸烟烟龄的增加,COHb含量和呼出气CO含量均呈增长趋势.