内燃机车交流传动系统牵引系统分析

论述交流传动技术在内燃机车上的实现及应用,在给出交流传动内燃机车主传动系统的控制框图的基础上对其进行原理性分析,建立异步牵引电动机与列车阻力的数学模型,对逆变器的控制规则进行探讨,并对交流传动内燃机车牵引过程和电阻制动过程进行计算机稳态仿真.     

中药肛滴在治疗消化道恶性肿瘤中的应用

探讨中药肛滴在治疗消化道恶性肿瘤中的应用。通过对６例典型病例的回顾分析,观察中药肛滴在缓解癌性粘连性肠梗阻、缓解消化道恶性肿瘤患者症状、提高晚期消化道恶性肿瘤患者生存质量的作用。应用中医理论“通则不痛”之说,对消化道恶性肿瘤患者进行中药肛滴治疗．认为有较好的临床效果。     

新生儿缺氧缺血性脑病血浆及脑脊液一氧化氮水平的变化

目的 :了解新生儿缺氧缺血性脑病 (HIE)时血浆和脑脊液 (CSF)中 NO水平的动态变化。方法 :采用硝酸根还原酶法 ,对 35例 HIE患儿 (轻度 10例、中度 13例、重度 12例 )分别于急性期、恢复期进行了血浆和 CSF NO水平测定。结果 :HIE急性期血浆 NO水平除轻度组外 ,中、重度组明显高于对照组 ,重度组又明显高于轻、中度组 ;恢复期轻、中、重度组血浆 NO水平均降至正常 ,与对照组比较差异无显著性。CSF中 NO水平增加的幅度与血浆成正比。结论 :血浆和 CSF中 NO水平与 HIE的脑损伤程度密切相关     

Effects of Mifepristone Compound on the Receptors of Estrogen and Progesterone in Early Pregnancy Deciduas

Mifeprlstone,a norethindrone, is the first synthetic effective steroid which canbind to the progesterone receptor with greater affinity than progesterone, but lacksthe agonistic effect. Its anti--progestin action results in the withdrawal of progesterone at cellular level to interrupt its biological action and can terminate early pregnancy['j. At present, the dose of mifepristone in combination with the analogue ofprostaglandin in terminating early pregnancy is 150 mg-- 200 mg and the complete…     

人工心脏圆盘泵的流动特性研究

人工心脏（血泵）一直存在泵体对血细胞剪切力过大和流速过快容易引起溶血的问题。为了研究人体正常血压情况下,血泵内部剪切力和速度场的分布情况,选择圆盘泵叶轮代替传统离心泵叶轮,对两种模型进行数值计算,分析不同叶轮内部剪切力和速度场的分布规律。研究表明传统离心泵内部流速高,叶片表面剪切力大,对血细胞的伤害大。圆盘泵相比传统离心泵,剪切力更小,流场速度分布均匀,流速更小。和传统离心泵相比,不同转速下圆盘泵能降低溶血的发生率。圆盘泵叶片数为6片时,抗溶血性能更好。研究结果为血泵的优化提供理论依据。     

Presynaptic inhibition of synaptic transmission in the rat hippocampus by activation of muscarinic receptors: involvement of presynaptic calcium influx

1. Modulation of presynaptic voltage-dependent calcium channels (VDCCs) by muscarinic receptors at the CA3–CA1 synapse of rat hippocampal slices was investigated by using the calcium indicator fura-2. Stimulation-evoked presynaptic calcium transients ([Ca_pre]_t) and field excitatory postsynaptic potentials (fe.p.s.ps) were simultaneously recorded. The relationship between presynaptic calcium influx and synaptic transmission was studied.
2. Activation of muscarinic receptors inhibited [Ca_pre]_t, thereby reducing synaptic transmission. Carbachol (CCh, 10 μM) inhibited [Ca_pre]_t by 35% and reduced fe.p.s.p. by 85%. The inhibition was completely antagonized by 1 μM atropine. An approximate 4^th power relationship was found between presynaptic calcium influx and postsynaptic responses.
3. Application of the N-type VDCC-blocking peptide toxin ω-conotoxin GVIA (ω-CTx GVIA, 1 μM) inhibited [Ca_pre]_t and fe.p.s.ps by 21% and 49%, respectively, while the P/Q-type VDCC blocker ω-agatoxin IVA (ω-Aga IVA, 1 μM) reduced [Ca_pre]_t and fe.p.s.ps by 35% and 85%, respectively.
4. Muscarinic receptor activation differentially inhibited distinct presynaptic VDCCs. ω-CTx GVIA-sensitive calcium channels were inhibited by muscarinic receptors, while ω-Aga IVA-sensitive channels were not. The percentage inhibition of ω-CTx GVIA-sensitive [Ca_pre]_t was about 63%.
5. Muscarinic receptors inhibited presynaptic VDCCs in a way similar to adenosine (Ad) receptors. The percentage inhibition of ω-CTx GVIA-sensitive [Ca_pre]_t by Ad (100 μM) was about 59%. There was no significant inhibition of ω-Aga IVA-sensitive channels by Ad. The inhibitions of [Ca_pre]_t by CCh and Ad were mutually occlusive.
6. These results indicate that inhibition of synaptic transmission by muscarinic receptors is mainly the consequence of a reduction of the [Ca_pre]_t due to inhibition of presynaptic VDCCs.

     

小儿肾小球疾病血清微量元素测定与分析

采用原子吸收分光光度法,测定了７８ 例肾小球疾病患儿血清铜、锌、铁、镁４ 种元素。结果显示,单纯性肾病组、肾炎性肾病组、紫癜性肾病组及肾炎组血清锌均显著低于正常组（ Ｐ＜ ００５）,血清铁、镁与正常组比较无显著差异。单纯性肾病组,肾炎性肾病组血清铜显著低于正常组（ Ｐ＜ ００５）。提示血清铜、锌、铁、镁含量的变化与疾病发生和疾病状态有关。     

睡眠呼吸暂停综合征患者夜间睡眠呼吸参数的变化及护理对策(英文)

目的：探讨睡眠呼吸暂停综合征（ＳＡＳ）患者夜间睡眠呼吸参数的变化及相应护理对策。方法：对１６例ＳＡＳ住院患者在治疗前、睡眠姿势训练、气道持续正压（ＣＰＡＰ）呼吸机治疗三种状态下,进行整夜多导睡眠仪监测。结果：在ＳＡＳ整夜呼吸紊乱中,零点以后其危险因素大大增加,出现严重低氧血症,血压升高,心律失常,尤其是呼吸暂停时间延长,次数增加。而侧卧位可显著地改善低氧血症,最低血氧饱和度（ＳａＯ２）从（６２±１９）％升高至（８３±１１）％（Ｐ＜０．０１）,ＣＰＡＰ呼吸机治疗能使呼吸调节障碍得到明显的恢复,呼吸暂停由（４４．３±２２．６）次降至（０．２５±０．５４）次（Ｐ＜０．０１）。结论：护理上应密切观察病情变化,特别是零点以后应加强巡视,除观察呼吸运动外还应警惕脑血管病及心脏疾病的发生,对不具备ＣＰＡＰ呼吸机治疗条件者宜采取睡眠时督促取侧卧位。对ＳＡＳ患者进行健康教育也是减少危险因素的重要护理措施。