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【目的】探讨中国人肝豆状核变性(WD)的分子发病机制和基因诊断的方法。【方法】应用基因工程技术对WD 进行了10 年的分子生物学研究。【结果】①WD 的基因定位研究:通过RFLP 及微卫星多态性分析, 应用两位点及多位点连 锁软件, 建立了中国人WD 基因在D13q14 .2 -3区域的精细遗传连锁图谱, 从而首次对中国人WD 基因进行了精确定位;②WD 基因突变研究:应用PCR-SSCP 及DNA 测序技术, 对39 个家系45 名WD 患者进行该致病基因的21 个外显子突变筛选, 发现 WD 基因5 号外显子存在新的T 插入突变, 并证实中国人WD 基因的突变热点为8 号外显子, 突变形式为Arg778Leu, 其频率 为22.8 %;③WD 的症状前诊断和杂合子检出:应用DNA 重组技术对79 个家系进行基因诊断, 成功地进行了WD 的症状前 诊断和杂合子检出, 并建立了WD 的基因筛选的PC R- Msp 1 酶切方法。【结论】中国人WD 基因定位与白种人基本相同, 但 基因突变热点不同, 其发病机制存在差异, 从而基因诊断的方法也不同。

目的: 筛选中国人肝豆状核变性的高频突变点。方法: 对中国人肝豆状核变性 39 个家系 45 个患者的 8 号、14 号外显子进行 PCR-SSCP 筛选,对有异常者进行序列分析(放射自显影) , 并通过该突变点的酶切再次筛选。结果: Exon 8 发 现有 3个泳动异常,两个为多态现象, 对 1 例明显异常者序列分析表明: ①患者的序列发现同义突变 C2250※G , 错义突变 G2273 ※T 发生 Arg778 Leu,引起功能缺失。患者上述两个突变同时存在。②患者父亲在 2250 位点 C 及 G 碱基同时存在, 在 2273 位点 G 及 T 碱基同时存在。 ③发现患者为纯合子, 其父为杂合子,母亲为正常序列。针对 Arg778 Leu 突变在所有病人中进 行酶切,发现 2 例纯合子占病人总数 4. 4%,11例杂合子占 24. 4%。酶切的阳性率为 28. 8%。结论: 本结果支持 8 号外显子 778 密码子作为中国人肝豆状核变性的高频突变点。本研究中出现类似杂合性丢失( LOH)现象, 提示 LOH 现象可能发生在 除肿瘤之外的其他遗传疾病中。Exon 14 未见异常,与欧洲人明显不同。

In response to the problem of high stubble damage rate during sugarcane harvesting, the interaction between sugarcane stalks and basecutter was analyzed, and a sugarcane stubble basecutting device was designed based on the combination of "sliding cutting and shearing cutting" to improve the cutting quality. The principle of unsupported cutting of traditional disc basecutters and supported cutting of sliding shear combination basecutters was analyzed. The result was shown that supported cutting could effectively reduce the bending resistance and inertia force of stems, thus preventing significant deformation of stems to a certain extent, effectively ensuring the cutting quality of stems, and sliding cutting can effectively reduce cutting resistance. The parameters of the key components of the basecutter were determined by establishing the force model of the stem. The sliding cutting operation is carried out using an equal sliding angle blade curve, and the sliding cutting angles and blade bevel angles were 40 ° and 45 °, respectively. The statics and modal analysis of the basecutter were conducted to prevent insufficient tool strength and resonance between the basecutter and the motor during shearing using ANSYS/Workbench. An optimal combination was achieved to fully meet the performance requirements, in terms of structural strength, where the yield strength of the basecutter was 450-650 MPa, while the maximum stress on the basecutter was 102 MPa, and the maximum displacement was 4.94×10-5m. The excitation frequencies of the cutting and the feeding motors were 0- 6.667 and 0-11.667 Hz, respectively. The modal analysis results show that the excitation frequencies of the two motors were much smaller than the first-order natural frequency of the basecutter (60.89 Hz). Therefore, the smooth operation of indoor experiments was obtained without any resonance. A basecutting test bench was built with adjustable cutting disc rotational speed, feeding speed, and cutting angle. The results of the single-factor test showed that when the cutting angle, cutting disc rotational speed, and feeding speed were 10-15 °, 140-220 r/min, and 1.1-1.7 m/s, respectively, the comprehensive evaluation value y was small and the cutting quality was better. The results of orthogonal experiment analysis of variance showed that each factor had a significant impact on the comprehensive evaluation value y. The range analysis of orthogonal experiments shows that the optimal experimental level is the cutting angle was 15 °, the cutting disc rotational speed was 180r/min, and the feeding speed is 1.4m/s. After experimental verification, the comprehensive evaluation values y were 0.256 and 0.298 at this time, indicated the cutting quality was better. Referring to the DG/T 117-2021 sugarcane harvesting machinery test method, the sugarcane stubble damage rate was inspected. The shear qualification rate was as high as 90.4%, and the stubble damage rate was reduced to below 10%. The operation quality of the sliding shear combined sugarcane basecutter met industry requirements. [ABSTRACT FROM AUTHOR]

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Machine-harvested sugarcane usually contains too many impurities, and subsequently the cane loss often occurs when the impurities were separated by the extractor. These problems make it difficult for the mechanized harvesting of sugarcane to be recognized by sugar mills and farmers, which seriously restricts the promotion of mechanized harvesting in China. In this study, taking the extractor of a segmented sugarcane harvester (model: 4GZQ-180) as the optimization object, a CFD method was used to explore the aerodynamic performance of a extractor, and thereby to propose the improvement scheme, finally to manufacture a prototype for the test. The impurity rate and cane loss rate were used as the main indexes to evaluate the performance of the extractor before and after optimization. The commercial CFD software Fluent was selected to analyze the airflow field nearby the whole extractor and the blade, in order to investigate the performance and defects of the prototype extractor. The SST k-ω model and the realizable k-ε model were utilized to calculate the turbulence near the blade and the turbulence in the extractor, respectively. The simulation results of flow field near the blade showed that the cusp of leading edge and trailing edge of blade can lead to the decrease of the lift, while, the increase of the drag. The simulation results of extractor flow field showed that: the discharge hood changed dramatically, and the airflow was blocked by the main shaft. These defects led to the serious separation of flow in the extractor. In the numerical simulation, the shape of blade was improved, and the maximum lift-to-drag ratio of the improved blade was significantly higher than that of the current blade. The cusp of discharge hood was eliminated after optimization, and the axis direction of main shaft was the same as the air flow direction. In order to further eliminate the flow separation, the cowl was installed outside the hydraulic motor, whereas, the cross-section shape of support frame was set to a streamline. The numerical simulation results showed that the air flow rate and efficiency of optimized extractor were greatly improved. The flow rate and power were selected as evaluation indexes to verify the accuracy of numerical simulation, indicating that the error between the calculated and measured value was about 10%. The experiments related to the impurity rate and cane loss rate were carried out to evaluate the performance of the extractor. The determination of impurity rate showed that the impurity rate of the optimized extractor was similar to the prototype extractor at a high speed (1 650 r/min), but it was significantly lower than that of the prototype extractor at medium (1 350 r/min) and low (1 050 r/min) speed. The determination of cane loss rate show that the cane loss rate of the optimized extractor was similar to that of the prototype extractor at low speed, but the cane loss rate was significantly reduced at medium and high speed. [ABSTRACT FROM AUTHOR]

目的 分析婴儿晚发型B族链球菌（GBS)化脓性脑膜炎的特点、治疗效果及转归情况，并与非GBS化脓 性脑膜炎进行比较。方法 GBS化脓性脑膜炎患儿24例纳人GBS组，以同期收治的21例非GBS化脓性脑膜炎 患儿作为对照组,收集两组患儿的的临床表现、实验室检查结果、影像学检查结果、治疗转归及预后资料并比较。 结果两组常见表现为发热、喂养困难、反应差、气促呻吟等。GBS组患儿外周血CRP高于对照组（P <0.01),脑 脊液葡萄糖水平低于对照组（P <0.05) ,GBS组合并轻中度贫血比例高于对照组（P <0.05)。GBS组头颅MRI检 查发现并发症发生率高于对照组(P <0.05)。GBS组采用青霉素类联合头孢曲松治疗4例，余均予万古霉素联合 三代头孢或美罗培南治疗;对照组选择三代头孢、美罗培南或万古霉素治疗。GBS组患儿住院时间、脑脊液葡萄糖 水平恢复正常所需时间较对照组延长(P均<0.05)。随访2个月~3.5年,GBS组生长发育基本正常7例、运动发 育落后8例、癫痫发作1例、放弃治疗后死亡3例、失访5例。对照组生长发育基本正常8例、运动发育落后4例、 癫痫发作2例、放弃治疗后死亡4例、失访3例。两组预后情况差异无统计学意义。结论晚发型GBS化脓性脑 膜炎临床表现无特异性，与非GBS化脓性脑膜炎相比更易合并贫血、治疗周期长、并发症发生率较高。 [ABSTRACT FROM AUTHOR]