Device-guided breathing exercises for the treatment of hypertension: An overview

The American Heart Association considers device-guided breathing as a reasonable treatment modality in their statement on non-pharmacological options for lowering blood pressure. This review discusses all randomized controlled trials that have investigated the effects of device-guided breathing on blood pressure in patients with hypertension. Thirteen studies were included in this review. In total, 627 patients were in-cluded, of which 365 patients were allocated to device-guided breathing. Only 6 studies used acceptable control groups: listening to music, meditative relaxa-tion exercises, or a sham-device. Two sponsored trials showed beneficial effects of device-guided breathing, both used listening to music as a control group. The remaining 4 studies, which had no employees of the manufacturer listed as co-author, observed no benefi-cial effects on blood pressure. There is only 1 study that used a sham device as a control group. All other studies were to some extend methodologically flawed. Based on the studies with an acceptable methodologi-cal quality, there is no clear evidence supporting a short-term beneficial effect on blood pressure by using device-guided breathing.

Design of New Elevator Pressure Guide Plate and Its Test Device

Pressure guide plate plays a certain role in the safe operation of elevator.Based on understanding the respective performance of new and old pressure guide plates,this paper analyses the problems existing in the original pressure guide plate.It also conducts stress analysis according to the function of pressure guide plate on elevator,and designs a new type of pressure guide plate combined with technological capability and equipment.According to the stress characteristics,a test device is designed and a comparative test is made between the new type of pressure guide plate and the old in order to test the reliability of the new type of pressure guide plate.The test proves that the new pressure guide plate of elevator can meet the requirements of product use and safe operation of elevator products.

Investigation of Working Bodies of the Device for Separation of Fibers Suitable for Spinning from Cotton Waste

It is known that fiber wastes (lint, down and seeds) produced at ginneries contain fibers that are suitable for spinning and can be used in industry, and their separation significantly increases the level of fiber production (1.9% - 2.5%). Based on these analyzes, the study aimed to create a new device that separates long fibers from lint and down. As a result, the amount of fiber output in the enterprise will increase and the enterprise will have significant economic benefits. In addition, the introduction of the device will prevent the addition of long fibers (longer than 16 mm) that can be used in the textile industry to the waste. This article focuses on the creation of a fiber separation device suitable for the treatment and spinning of fibrous waste produced in ginneries. The study theoretically examined the main working bodies of the fiber separation device from waste. Theoretical research is devoted to the study of the strength of the main working body of the fiber separation device−the separating saw drum and its shaft. In the study, the sawdust drum is a more stressed steel coating, and it was found that the strength reserve of this drum is [δТ] = 2.03 (where δТ = 0.8 - 2.5) was found to be. As a result of calculating the resistance of the saw drum shaft to stiffness and vibration, it was determined that the shafts are resistant to vibration under periodic loading and that the oscillation frequency along its axis through the critical rotation frequency is vcr=10.3 Gts.

Determination of Technological Parameters of Fiber Separation Device from Cotton Waste

This article examines the technological parameters of the device for the separation of fibers suitable for spinning by processing fibrous waste from the technological processes of ginneries. Technological processes in the cotton ginning industry include a complex of physical and mechanical advantages, the successful study of which is possible only with the use of modern achievements in science and technology. Therefore, it is advisable to conduct scientific research based on mathematical modeling. To justify the effective operation of the selected design of the cotton fiber separation device, it is necessary to select its optimal technological parameters. Improving the efficiency of the process of separation of spinning fibers from the composition of fibrous waste depends directly on technological parameters. The application of mathematical methods in the planning and conduct of research allows for determining the individual effects of the interaction of several factors that characterize the combined parameters of the optimization parameters, in contrast to traditional computational methods of research. As a result, it will be possible to obtain a mathematical model of the object understudy in a relatively small number of tests, which will simultaneously serve to obtain optimal solutions.

Design and optimization of the seed conveying system for belt-type highspeed corn seed guiding device

Seeding is an important part of improving corn yield.Currently,seed guide tubes are mostly used as transport devices.But the existing seed guide tubes cannot meet the requirements or achieve the goal of fixing the seed falling trajectory.A seed collision phenomenon occurs occasionally.So,in response to the problems that the seeds and seed guide tube collide or bounce under high speed operation,which results in a lower sowing qualification rate and poor spacing uniformity,a seed receiving and conveying system comprising a belt-type high-speed corn seed guiding device was designed and optimized,to meet the needs of high-speed precision sowing operations and improve the spacing uniformity.The factors affecting the seed conveying performance were obtained by analyzing the mechanical properties of the seeds at various movement stages.These factors were the number of seed cavities between adjacent seeds,the forward speed,the height from the ground,and the installation angle.Single factor simulation experiments were conducted by selecting the paddle spacing as the test factor and using the pass rate,reseeding rate,omission rate and coefficient of variation as the evaluation indexes to investigate the influence of the paddle spacing on the seed guide performance of the device and further determine the structural parameters of the paddle belt.Orthogonal rotation combination tests of three factors and five levels were also conducted through bench testing.Then the test outcomes were optimized.The results indicated that the best results were obtained when the number of seed cavity intervals between adjacent seeds was 5.16,the installation angle was 79.40°,and the height from the ground was 31.84 mm.At this time,the qualified rate was 98.49%,the repeated sowing rate was 0.48%,the missed sowing rate was 1.03%,and the coefficient of variation was 6.80%.Experiments were used to validate the optimization results,and all of the obtained index data satisfied the criteria for accurate and quick corn sowing.The study’s findings can serve as a theoretical foundation for a belt-type high-speed corn seed guiding device optimization test.

Endoscopic ultrasound guided fine needle tissue acquisition:Where we stand in 2013?

Since its introduction,endoscopic ultrasound(EUS)guided fine needle aspiration and fine needle biopsy have become an indispensable tool for the diagnosis of lesions within the gastrointestinal tract and surrounding organs.It has proved to be an effective diagnostic method with high accuracy and low complication rates.Several factors can influence the accuracy and the diagnostic yield of this procedure including experience of the endosonographer,availability of onsite cytopathology services,the method of cytopathology preparation,the location and physical characteristics of the lesion,sampling techniques and the type and size of the needle used.In this review we will outline the recent studies evaluating EUS-guided tissue acquisition and will provide practical recommendations to maximize tissue yield.

Electrocautery vs non-electrocautery dilation catheters in endoscopic ultrasonography-guided pancreatic fluid collection drainage

AIM: To investigate the safety and utility of an electrocautery dilation catheter for endoscopic ultrasonography(EUS)-guided pancreatic fluid collection drainage.METHODS: A single-center, exploratory, retrospective study was conducted between August 2010 and August 2014. This study was approved by the Medical Ethics Committee of our institution. Informed, written consent was obtained from each patient prior to the procedure. The subjects included 28 consecutive patients who underwent EUS-guided transmural drainage(EUS-TD) for symptomatic pancreatic and peripancreatic fluid collections(PFCs) by fine needle aspiration using a 19-gauge needle. These patients were retrospectively divided into two groups based on the use of an electrocautery dilation catheter as a fistula dilation device; 15 patients were treated with an electrocautery dilation catheter(electrocautery group), and 13 patients were treated with a non-electrocautery dilation catheter(non-electrocautery group). We evaluated the technical and clinical successes and the adverse events associated with EUS-TD for the treatment of PFCs between the two groups.RESULTS: There were no significant differences in age, sex, type, location and diameter of PFCs between the groups. Thirteen patients(87%) in the electrocauterygroup and 10 patients(77%) in the non-electrocautery group presented with infected PFCs. The technical success rates of EUS-TD for the treatment of PFCs were 100%(15/15) and 100%(13/13) for the electrocautery and the non-electrocautery groups, respectively. The clinical success rates of EUS-TD for the treatment of PFCs were 67%(10/15) and 69%(9/13) for the electrocautery and the non-electrocautery groups, respectively(P = 0.794). The procedure time of EUS-TD for the treatment of PFCs in the electrocautery group was significantly shorter than that of the non-electrocautery group(mean ± SD: 30 ± 12 min vs 52 ± 20 min, P < 0.001). Adverse events associated with EUS-TD for the treatment of PFCs occurred in 0 patients and 1 patient for the electrocautery and the non-electrocautery groups, respectively(P = 0.942).CONCLUSION: EUS-TD using an electrocautery dilation catheter as a fistula dilation device for the treatment of symptomatic PFCs appears safe and contributes to a shorter procedure time.

移动式多点出料装置设计与试验

目前,筒仓仓群的进料传统工艺路线是在每个仓顶上布置有一台带式输送机,通过搭接方式由一台传递给另一台,实现物料的连续输送。其在每台带式输送机的出料口处设置有三通,一通流向料仓仓顶的进料点,一通流向下台带式输送机,导致工艺配置复杂、设备布置繁琐,操作起来不方便,故障率也会增高。为此,设计了一种移动式多点出料装置,包括:机架布置在输送机托架上方,托架上固定有滑轨;滚轮、驱动机安装在机架上且二者传动连接;导向托架与机架固定,其上安装有出料辊和托辊组,出料辊与托辊组共同对输送带进行滚动支撑,导向托架的一端固定有出料斗,其出料端布置在输送机托架一侧。上述设置保证了带式输送机出料位置可调,当需要对依次排列的多个料仓进行输送进料时,只需要布置一台带式输送机即可。样机调试运行及对生产试验结果表明:装置设计的各项技术指标均符合国家标准的规定和设计规范要求,能够满足市场需求和生产需要,解决了料仓仓顶多点进料的工艺难点。

谷子穴播机勺链式导种装置设计与试验

针对谷子播种时在导种管内弹跳严重,导致谷子落地后成穴性差的问题,设计了一种谷子穴播机勺链式导种装置。其工作原理为通过约束种子运移轨迹提高其落地后成穴性,对关键零部件进行了设计,对纳种与投种过程进行了运动分析,确定了影响导种性能的重要因素。为获得最佳参数组合,分别以圆形勺、方形勺、方形平嘴勺3种种勺型式和ABS、橡胶、亚克力3种材料为因素进行单因素试验,试验结果表明方形平嘴勺和橡胶材料效果最佳。在此基础上,以纳种角度、纳种高度和链轮转速为纳种试验因素,以纳种合格率为评价指标;以投种高度、投种角度和链轮转速为投种试验因素,以穴径合格率、穴粒数合格率及穴距变异系数为投种评价指标,通过EDEM离散元仿真软件分别进行纳种过程与投种过程的三因素五水平二次正交旋转组合仿真试验。纳种过程最佳参数组合为:纳种角度45.95°、纳种高度74.05 mm、链轮转速1.76 r/s;投种过程最佳参数组合为:投种角度53.51°、投种高度25.96 mm、链轮转速1.98 r/s。为进一步验证导种装置性能,在最佳参数组合下进行台架验证试验与对比试验,验证试验中纳种合格率为95.53%、穴径合格率为93.29%、穴粒数合格率为94.73%、穴距变异系数为7.46%,台架验证试验结果与仿真试验结果基本一致,相对差值均小于5%;对比试验结果表明,安装勺链式导种装置的播种效果明显优于安装导种管的播种效果,穴径合格率、穴粒数合格率、穴距变异系数最大可提高2.75、3.43、3.25个百分点。

Woven EndoBridge血流导向装置用于治疗颅内血管分叉部宽颈动脉瘤

血管内介入已成为治疗颅内动脉瘤的重要手段。对于解剖结构复杂的血管分叉部宽颈动脉瘤,临床常采用“Y”形和“T”形双支架双微导管组合栓塞技术或单支架辅助弹簧圈栓塞技术予以治疗[1-2],操作方法复杂,治疗中及治疗后血栓形成及复发风险较高。Woven Endo Bridge(简称WEB装置)为新型自膨式瘤内扰流装置,由多条镍钛合金网丝编织而成,可置于瘤体内封堵瘤颈,并通过血液扰流封闭血管分叉部宽颈动脉瘤[3]。本研究观察WEB装置用于治疗颅内血管分叉部未破裂宽颈动脉瘤的效果。

集聚赛络纺纱导流装置的设计与应用

针对集聚赛络纺纱系统能耗较大的问题,设计3种导流装置,以降低集聚赛络纺纱系统的负压,达到节能降耗的效果。首先通过solidworks软件建立集聚赛络纺纱集聚区三维物理模型,利用fluent进行数值模拟,分析集聚区气流场的分布情况;然后通过纺纱实验进一步验证导流装置能够起到节能降耗的效果。结果表明:出口负压越大,集聚槽附近的速度越大,集聚槽上方的气流对须条起到挤压作用,使须条紧紧贴在网格圈表面,集聚槽侧向气流使须条宽度减小,须条表面的毛羽能够卷入到纱体表面,形成紧密的结构,从而能够减小甚至消除加捻三角区;使用所设计的3种导流装置(集聚负压1000 Pa)纺制出来的纱线与普通集聚赛络纱(集聚负压2000 Pa)质量相当,甚至更好。

气力辅助充种式花生精量排种器设计与试验

针对花生播种向精准、高速方向发展过程中高速作业状态下花生种子充种效果差的问题,设计了一种气力辅助充种式花生精量排种器,重点设计了排种器排种盘结构和气力辅助充种结构。针对颗粒尺寸大、质量大的花生种子,通过对花生种子在排种器中堆积现象与充种时间进行分析,得出花生高速排种充种过程需增强充种性能,从而提高充种效率。通过对花生种子进行充种原理分析,阐明花生种子充种过程中种子与排种器的运动关系与受力关系,分析充种过程影响因素。通过设计带有导种槽的排种盘和带有辅助吹种型孔的辅助充种结构,分析计算排种盘吸种孔、导种槽的关键结构参数以及辅助吹种型孔参数与排列方式。以充种合格率和充种漏充率为指标,进行三因素三水平组合试验,对试验结果进行多元回归分析,以最优目标进行优化,确定排种盘最佳参数组合为排种器吸种负压5.156 kPa、花生高速播种机前进速度8.007 km/h、扰动吹种正压1.149 kPa,此时,花生充种合格率为95.84%、漏充率为4.06%,能够实现花生种子有效充种。

赛络集聚纺导流装置的优选

为评估3种集聚导流装置在纺纱工艺中的应用效果,选取单根定量为6.025 g/10 m的粘胶粗纱进行赛络集聚纺纱试验。通过控制负压大小和加装不同的导流装置,设计5种方案进行纺纱,测试5种纺纱方案的纱线质量,并对赛络集聚纺集聚区进行仿真模拟,优选导流装置。结果表明:3种导流装置能够降低成纱3 mm毛羽数,提高成纱断裂强度,对条干CV影响不大,但能适当降低成纱棉结以及粗细节;在相同负压(1000 Pa)条件下,对比加装3种导流装置与不加装导流装置的成纱质量,导流装置Ⅰ降低成纱3 mm毛羽数幅度最大,为30.8%,提高成纱断裂强度增幅最大,为14.5%,纺纱效果最好;通过流场仿真模拟,对比3种导流装置在集聚区上的数值模拟结果,应用导流装置Ⅰ的模拟气流速度最大,为42 m/s,理论效果最好。认为:3种导流装置均能够在保证成纱质量的前提下降低集聚负压,并且导流装置Ⅰ应用效果最好。

液体火箭发动机热试车启动中导流锥对燃气管路流动特性影响研究

双推力室液体火箭发动机启动过程中,若出现两支管流量分配不均等现象,极易引起点火失败,造成重大损失。因此,燃气管路分叉处内部流动特性和在分叉处布置导流锥对改善流动特性影响的研究具有重要意义。本文针对某双推力室液体火箭发动机热试车启动过程中的燃气管路,以试验数据作为边界条件,开展了瞬态流动数值仿真研究。结果表明,火箭发动机热试车启动过程中,燃气管路流动呈现出4个典型阶段,分别为点火前的平稳期、点火后的一次上升期、下降期和二次上升期。在启动过程中,无导流锥时,导流罩进口存在预旋回流区、一侧出口存在滞止回流区,导流罩与燃气支管衔接处内侧存在转弯回流区,三者相互作用是造成两支管间压力分布不对称及出口质量流量分配不平衡的主要原因;有导流锥时,预旋回流区被导流锥约束而缩小,滞止回流区消失。有导流锥与无导流锥时相比,在启动过程中约0.2 s与0.6 s时刻,两支管对称测点压差均值分别降低约80.0%与80.0%,两支管出口质量流量差值分别降低约55.0%与80.8%。导流锥有效改善了流动特性,使得两支管压力分布的对称性提高,流量分配平衡性增强。导流锥对双推力室液体火箭发动机稳定性提高有重要作用。

骨折复位固定系统的设计和临床前研究

目的探讨骨折复位固定系统的安全性、有效性和临床应用价值。方法描述骨折复位固定系统组件克氏针限位器和克氏针导向锁紧器的设计和应用;6个医生根据手感或应用克氏针限位器在合成骨中植入克氏针,测量克氏针穿出骨的长度;克氏针导向锁紧器配合锁定板及2根直径1.5 mm克氏针、2根直径1.5 mm克氏针和2根直径2.0 mm克氏针固定合成骨构建的骨折模型,测量结构的失效扭矩。结果克氏针限位器降低了克氏针穿出骨的长度,差异有统计学意义(P<0.001),克氏针导向锁紧器配合锁定板及2根直径1.5 mm克氏针固定骨折失效扭矩高于2根直径1.5 mm克氏针和2根直径2.0 mm克氏针固定骨折(P<0.05)。结论骨折复位固定系统是提供复位和固定骨折、判断和优化锁定板螺钉位置及保护骨折块血运的新技术。

急倾斜工作面导向式架前挡矸装置设计

针对传统急倾斜工作面架前挡矸装置出现的稳定性差、适应能力弱及千斤顶活塞杆和密封件易损坏等问题,设计了一种急倾斜工作面导向式架前挡矸装置,有效地解决了传统急倾斜工作面架前挡矸装置出现的一系列问题。

硬膜外粘连闭合松解器治疗腰椎手术失败综合征疗效及安全性评价

目的 观察计算机断层扫描(computed tomography,CT)引导下硬膜外粘连闭合松解器治疗腰椎手术失败综合征(failed back surgery syndrome,FBSS)的临床疗效及安全性。方法 选取解放军总医院第三医学中心骨科和康复医学科就诊的FBSS患者80例,根据随机数字表法分为治疗组和对照组,各40例。治疗组采用硬膜外粘连闭合松解器治疗,1次/周,第2次治疗在第1次治疗2周后进行,共治疗2次;对照组予低频治疗,每次30 min,3次/周,共治疗2周,治疗结束后对比两组疗效。治疗前和治疗后1个月、3个月、6个月采用视觉模拟评分法(visual analogue scale,VAS)、改良Oswestry功能障碍指数(Oswestry disability index,ODI)和健康调查简表(the MOS item short from health survey,SF-36)进行评定,同时填写不良事件表进行安全性研究。结果 治疗6个月后,两组患者VAS评分及ODI评分均较治疗前降低(P<0.01),且治疗组显著优于对照组(P<0.01);对于SF-36评分,治疗6个月后,除对照组情感职能维度外,两组各维度均较治疗前显著改善(P<0.01),且在生理功能维度治疗组改善优于对照组(P<0.05),其余各维度治疗组改善显著优于对照组(P<0.01)。研究过程中仅治疗组发生晕针1例,两组均无严重不良反应发生(P>0.05)。结论 CT引导下硬膜外粘连闭合松解器治疗FBSS疗效确切,不良事件发生率低,可显著减轻FBSS患者疼痛程度,改善功能障碍。

基于可穿戴式步行引导仪的可视化步行训练对帕金森病冻结步态患者步行能力的影响

目的:探讨基于可穿戴式步行引导仪的可视化步行训练对帕金森病冻结步态患者步行能力的影响。方法:选取23例帕金森病冻结步态患者为试验组,同时选取20例性别、年龄等匹配的健康者为对照组。试验组给予利用可穿戴式步行引导仪的可视化步行训练,20min/次,2次/日,训练1周。利用Vicon三维步态分析系统收集试验组训练前后和对照组时空参数、非优势侧及优势侧运动学参数、非优势侧及优势侧地面反作用力参数(包括前-后侧峰值、内-外侧峰值及纵向第一峰值)。结果:(1)训练后,试验组患者步速及双侧步长均明显增加,步频、双支撑期明显减小,与训练前相比,差异均有显著性意义(P<0.05);训练后,试验组患者优势侧步长、步频及双支撑期与对照组比较,差异均无显著性意义(P>0.05)。(2)训练后,试验组患者双侧髋关节着地角度、踝背屈及跖屈最大角度及下肢关节活动范围均明显增加,膝关节着地角度减小,踝关节第一峰值出现的阶段延迟,与训练前相比,差异均有显著性意义(P<0.05);训练后,试验组患者双侧(膝关节着地角度、踝背屈最大角度、踝关节第一峰值出现阶段、下肢关节活动范围)和优势侧(髋关节着地角度、踝跖屈最大角度)与对照组比较,差异均无显著性意义(P>0.05)。(3)干预后,试验组患者双侧地面反作用力前-后侧峰值及纵向第一峰值明显提高,地面反作用力内-外侧峰值明显下降,差异均有显著性意义(P<0.05)。与对照组相比,非优势侧后侧峰值、内侧峰值及优势侧各项参数均无显著性差异(P>0.05)。结论:基于可穿戴式步行引导仪的可视化步行训练可有效提高帕金森病冻结步态患者步行平衡稳定性及步伐连贯性。

自制导引器经皮置入螺钉内固定治疗股骨颈骨折

目的探讨自制导引器经皮置入螺钉内固定治疗股骨颈骨折的疗效。方法采用自制导引器经皮置入螺钉内固定治疗8例股骨颈骨折患者。记录术中透视次数、钻孔次数、骨折复位情况、骨折愈合时间、髋关节功能恢复情况。结果患者均获得6个月随访。术中透视5~12次,术中钻孔3~10次。术后X线片显示骨折均解剖复位。骨折均愈合,时间3~6个月。末次随访时,髋关节Harris评分85~96分,其中优5例,良3例;患者均可扶拐行走,髋关节无疼痛。结论采用自制导引器经皮置入螺钉内固定治疗股骨颈骨折,操作方便,可减少透视次数及钻孔次数,而且能明显提高置钉的准确性,使空心螺钉呈经典的倒三角排列,进一步提升了固定的稳定性。

细支ZJ17机组烟丝成型关键部件改进

针对细支烟烟丝结构特性,对ZJ17机组烟丝成型关键部位进行研究。通过对抛丝辊、吸丝带导轨、平准器及劈刀盘材质等核心部件进行创新性改进,提高烟丝供料松散度、均匀性,降低烟丝运行的阻力和造碎等,为大幅提高细支ZJ17机组生产效率和质量水平提供技术方案。