基于有限元分析切割球囊对冠状动脉钙化病变 预处理效果

目的 探讨切割球囊在浅部冠状动脉钙化病变预处理中的适用范围,以减少其在钙化病变治疗中严重并发症的发生。方法 采用有限元方法,以普通球囊为对照分析切割球囊对不同弧度、厚度和长度钙化斑块的作用效果。将钙化斑块厚度设置为0.3、0.4 mm,长度设置为2、4 mm。并根据血管内超声(intravenous ultrasound, IVUS)钙化严重程度分级,设置钙化弧度为120°、180°、270°和360°,共16种钙化斑块。对钙化斑块使用脆性断裂模块来模拟钙化断裂情况,在预处理仿真的基础上进行支架虚拟植入,使用钙化断裂情况和支架圆形率来评价预处理效果。结果 对于浅部钙化病变,在小于120°病变中,球囊无法解除钙化斑块阻碍,支架圆形率为82.75%。在厚度小于0.3 mm的180°钙化病变中,切割球囊在1 215.9 kPa下使钙化发生断裂,支架后圆形率为74.42%;普通球囊在安全扩张压力(1 418.55 kPa)下无法使钙化发生断裂。在270°小于0.3 mm厚钙化病变,普通球囊在1 013.25 kPa下产生3处断裂;切割球囊在1 013.25 kPa下产生2处断裂,球囊无法使厚0...     

Efficiency of Tool Steel Cutting by Water Jet with Recycled Abrasive Materials

High-pressure water jet machining is characterized by wide possibilities of cutting diverse materials together with multi-layer materials with dissimilar properties, accurate cutting complex profiles, as well as conducting them in uncommon conditions, especially in cases of thick materials. An additional advantage of water jet technology is its environmental friendliness. This paper presents tests of the cutting performance of tool steel with the use of an abrasive water jet (AWJ). The state-of-the-art has shown insufficient scientific evidence in AWJ tool steels cutting using recycled abrasive materials. Therefore, the main motivation for this paper was to carry out research from an environment aspect. The reuse of abrasives and the use of recycled materials have immense potential to reduce processing costs while remaining environmentally friendly. The RSM method was used for modeling and optimization. A response surface design (RSM) is a package of an advanced design-of-experiment (DOE) approaches that support better understanding and optimize response, exploring the relationships between several explanatory variables and one or more response variables. Based on this research, feed rate is the key factor influencing the depth of cut, while the water nozzle diameter has a secondary effect, and the concentration of abrasive has the least influence on the depth of cut. High level of variance (the percentage of variability in the reaction that is interpreted by the formula) confirms that the models fit well to the investigational data.     

低位截断切开隧道引流高位挂线治疗高位肛瘘34例

采用低位截断切开隧道引流,高位挂线治疗高位肛瘘34例,疗效满意.此法较单纯的切开挂线术有疗程短,肛门瘢痕小,不易变形等优点.     

趁鲜切制和传统切制金荞麦饮片糖类组分比较研究

目的 比较趁鲜切制和传统切制方法对金荞麦Fagopyri Dibotryis Rhizoma饮片糖类组分的影响,基于糖组分探究适宜的金荞麦饮片切制方法。方法 采用多维色谱技术表征2种饮片中多糖含量、相对分子质量分布、单糖组成及物质的量比以及寡糖和游离单糖的含量,结合统计分析,比较2种饮片的糖组分特征。结果 与传统切制法相比,趁鲜切制饮片中多糖、寡糖含量较高;2种饮片中多糖的相对分子质量分布范围相似,但传统方法切制饮片在4.456×10⁶～8.095×10⁶区域占比较高;2种饮片多糖都主要由D-甘露糖、D-半乳糖醛酸、D-葡萄糖、半乳糖和阿拉伯糖组成,但传统方法切制饮片的D-葡萄糖物质的量比较高,D-甘露糖、半乳糖和阿拉伯糖物质的量比较低。结论 趁鲜切制能更好地保留多糖和寡糖组分,且操作方法相对简便,可以考虑作为金荞麦饮片的候选切制方法。     

鼻丘、下鼻甲割治法治疗变应性鼻炎的关键技术及其分子机制的研究

目的：　探究鼻丘、下鼻甲割治法治疗变应性鼻炎（allergic rhinitis,AR）的关键技术及其分子机制。方法：　收集2019年3月2日至2020年5月30日于成都中医药大学附属医院耳鼻喉科接受鼻丘、下鼻甲割治法治疗的85例AR患者临床资料,其中男32例、女53例,年龄（35.74±10.24）岁。采用视觉模拟量表（visual analogue scale,VAS）评分比较不同割治部位、割治方向、割治深度在治疗后1周、4周、8周、12周的疗效。进一步采用ELISA检测治疗前后患者血清中γ干扰素（interferon-gamma,IFN-γ）、免疫球蛋白E（immunoglobulin E,IgE）、白介素-4（interleukin-4,IL-4）的含量,用HE染色和甲苯胺蓝染色检测治疗前后患者的嗜酸性粒细胞和肥大细胞,用Western blot、qPCR检测治疗前后患者降钙素基因相关肽（calcitonin gene related peptide,CGRP）和P物质（substance P,SP）的表达量。采用SPSS 22.0进行统计学分析。结果：　鼻丘联合下鼻甲割治疗效明显优于单纯鼻丘割治和单纯下鼻甲割治（P<0.05）。鼻丘割治的3个方向疗效没有差异。下鼻甲割治深度达骨质层,明显优于黏膜和黏膜下;ELISA实验表明治疗后的AR患者IFN-γ（t=6.069,P<0.001）含量明显上升,IgE（t=6.954,P<0.001）和IL-4（t=12.060,P<0.001）含量明显下降。HE染色和甲苯胺蓝染色表明治疗后患者的嗜酸性粒细胞浸润明显减少,肥大细胞的活性明显下降。Western blot实验表明AR患者治疗后的CGRP（t=11.130,P=0.008）和SP（t=11.930,P=0.007）与治疗前相比明显下降。qPCR实验表明AR患者治疗后的CGRP（t=11.640,P=0.007）和SP（t=7.104,P=0.002）与治疗前相比明显下降。结论：　割治部位和割治深度是鼻丘、下鼻甲割治法的关键技术参数,该割治法可以减轻鼻腔黏膜炎症,其分子机制可能是降低CGRP和SP表达。     

基于既病防变思想探讨中西医结合综合防治乳腺癌

通过总结中西医对乳腺癌病因病机的认识及分析典型病例的诊治过程,探讨"既病防变"思想在中西医结合综合防治乳腺癌的指导作用."既病防变"在临床诊治疾病中主要体现于"截断扭转"和"先安未受邪之地"两种原则.由乳腺癌早期即有血行转移的特性可知,临床治疗乳腺癌的成败不仅与外科手术彻底清除局部病灶有关,更依赖于中西医结合的整体综合...     

Extraction and Reconstruction of Arbitrary 3D Frequency Features from the Potassium Dihydrogen Phosphate Surfaces Machined by Different Cutting Parameters

To comprehensively analyze the effect of cutting parameters on the 3D surface topography of machined potassium dihydrogen phosphate crystals, 2D power spectrum density and continuous wavelet transform are used to extract and reconstruct the arbitrary actual 3D frequency features of machined potassium dihydrogen phosphate crystal surfaces. The 2D power spectrum density method is used to quantitatively describe the 3D surface topography of machined potassium dihydrogen phosphate crystals. The continuous wavelet transform method is applied to extract and reconstruct 3D topographies of arbitrary actual spatial frequency features in machined surfaces. The main spatial frequency features f_x of the machined surfaces are 0.0056 μm⁻¹, 0.0112 μm⁻¹, and 0.0277 μm⁻¹ with the cutting depth from 3 μm to 9 μm. With the feed rate changing from 8μm/r to 18 μm/r, the main spatial frequency features f_x are 0.0056 μm⁻¹–0.0277 μm⁻¹. With the spindle speed from 1300 r/min to 1500 r/min, the main spatial frequency features f_x are same as the main spatial frequency features of the cutting depths. The results indicate that the variation of cutting parameters affects the main spatial frequency features on the 3D surface topography. The amplitudes of the spatial middle-frequency features are increased with the increasing of cutting depth and spindle speed. The spatial low-frequency features are mainly affected via the feed rate. The spatial high-frequency features are related to the measurement noise and material properties of potassium dihydrogen phosphate. The distributional directions of the frequency features in the reconstructed 3D surface topography are consistent with the distribution directions of actual frequency features in the original surface topography. The reconstructed topographies of the spatial frequency features with maximum power spectrum density are the most similar to the original 3D surfaces. In this machining, the best 3D surface topography of the machined KDP crystals is obtained with a cutting depth a_p = 3 μm, feed rate f = 8 μm/r and a spindle speed n = 1400 r/min.     

Temperature Optimization by Using Response Surface Methodology and Desirability Analysis of Aluminium 6061

Because aluminium is a lightweight and low-density material, its alloys, such as Al 6061 alloy, are extensively used in numerous automobile, defense, and aviation components. This study aims to develop a predictive model to investigate the impact of tool nose radius on the CNC turning process of Al 6061 alloy and better recognize the implications of operating machining considering cutting speed, rate of feed, cutting depth, and tool nose radius. The trials were carried out by using the response surface methodology (RSM), with an Al₂O₃ coated carbide tool as the cutter and an Al 6061 workpiece as the material. A mathematical model of the second-order was created. The analysis of variance (ANOVA) approach was used to analyze the performance characteristics of the turning operation. Individual desirability values from the desirability function analysis for the multi-responses are used to construct a composite desirability value. The ideal parameter levels were determined by using the composite desirability value, and the significant impact of parameters was assessed by using the analysis of variance. The minimum temperature attained at the machining parameters are 98.0 m/min cutting speed, 0.26 mm/rev rate of feed, 0.893 mm cutting depth, and 0.84 mm tool nose radius. The best total desirability value is 23.615 °C, indicating that the experimental results are close to the predicted values.     

Biofilm on and structural damage of rotary cutting instruments after 5 cycles of clinical use and processing

BackgroundRotary cutting instruments (RCIs) are sterilized routinely. The authors aimed to analyze the structural integrity, presence of dirt, and microbial contamination of RCIs used in clinical practice after processing.MethodsEighty-four RCIs (42 carbide burs, 42 diamond burs) were divided into baseline, control, and test groups. The RCIs were evaluated by means of scanning electron microscopy and microbiological analysis. Evaluation criteria included presence of structural damage, dirt, biofilm, and isolated cells and their phenotypic profile.ResultsThe carbide burs from all groups and diamond burs from the test groups had structural damage. Dirt was observed in the baseline and test groups. Three bacterial species were isolated from 4 RCIs (9.52%). An isolated cell was observed from 1 carbide bur. Biofilm was observed on 3 RCIs (7.14%).ConclusionsRCIs should not be subjected to multiple uses; after the first clinical use they accumulate structural damage and dirt that hampers the cleaning step, causing failure in the sterilization process.Practical ImplicationsThe presence of microorganisms and structural damage on the RCIs confirmed that they are not amenable to processing, a fact that characterizes them as a single-use health care product.     

Cutting balloon for femoral arterial and venus obstructions due to suture-based closure devices: Case series

Suture-based vascular closure devices have been shown to be effective in hemostasis for procedures with vascular access. However, iatrogenic vascular occlusion may occur. The cutting balloon (CB) is a noncompliant balloon wrapped with 3–4 microsurgical blades that are intended to modify vascular lesions, but it may also be utilized to cut and release endovascular sutures. We report two cases in which the CB was employed as a bailout strategy to alleviate suture-related vascular occlusion after transcatheter aortic valve replacement. The CB can be effectively utilized to resolve suture-related vascular occlusion.