Influence of Tricuspid Bioprosthetic Mitral Valve Orientation Regarding the Flow Field Inside the Left Ventricle: In Vitro Hydrodynamic Characterization Based on 2D PIV Measurements

The flow patterns of a prosthetic heart valve in the aortic or mitral position can change according to its type and orientation. This work describes the use of 2D particle image velocimetry (PIV) applied to the in vitro flow fields characterization inside the upper part of a left ventricular model at various heart rates and as a function of two orientations of stented tricuspid mitral bioprostheses. In the ventricular model, each mitral bioprosthesis (27 and 31 mm diameter) was installed in two orientations, rotated by 180°, while the aortic bileaflet mechanical valve (27 mm diameter) remained in a fixed orientation. The results (N = 50) showed changes in the intraventricular flow fields according to the mitral bioprostheses positioning. Also, changes in the aortic upstream velocity profiles were noticed as a function of mitral orientations.     

Experimental and Numerical Investigation of an Axial Rotary Blood Pump

Left ventricular assist devices (LVADs) have become a standard therapy for patients with severe heart failure. As low blood trauma in LVADs is important for a good clinical outcome, the assessment of the fluid loads inside the pump is critical. More specifically, the flow features on the surfaces where the interaction between blood and artificial material happens is of great importance. Therefore, experimental data for the near‐wall flows in an axial rotary blood pump were collected and directly compared to computational fluid dynamic results. For this, the flow fields based on unsteady Reynolds‐averaged Navier–Stokes simulations‐computational fluid dynamics (URANS‐CFD) of an axial rotary blood pump were calculated and compared with experimental flow data at one typical state of operation in an enlarged model of the pump. The focus was set on the assessment of wall shear stresses (WSS) at the housing wall and rotor gap region by means of the wall‐particle image velocimetry technique, and the visualization of near‐wall flow structures on the inner pump surfaces by a paint erosion method. Additionally, maximum WSS and tip leakage volume flows were measured for 13 different states of operation. Good agreement between CFD and experimental data was found, which includes the location, magnitude, and direction of the maximum and minimum WSS and the presence of recirculation zones on the pump stators. The maximum WSS increased linearly with pressure head. They occurred at the upstream third of the impeller blades and exceeded the critical values with respect to hemolysis. Regions of very high shear stresses and recirculation zones could be identified and were in good agreement with simulations. URANS‐CFD, which is often used for pump performance and blood damage prediction, seems to be, therefore, a valid tool for the assessment of flow fields in axial rotary blood pumps. The magnitude of maximum WSS could be confirmed and were in the order of several hundred Pascal.     

对比剂注射技术在冠状动脉CTA成像中的应用

目的 探讨对比剂注射技术在冠状动脉CTA成像中的应用.方法 收集150例行冠状动脉CTA成像患者,随机抽取50例二期相对比剂注射技术为A组,三期相对比剂注射技术分B1组(1.0 mL/kg)和B2组(0.8mL/kg)各50例.A组:一期碘普罗胺1.0 mL/kg,注射速率4.5mL/s;二期生理盐水30 mL,注射速率4.0 mL/s.B1组:一期碘普罗胺按1.0 mL/kg对比剂总量的75％,注射速率4.5 mL/s;二期碘普罗胺按对比剂注射总量的25％+生理盐水按1:1浓度,注射速率4.0 mL/s;三期生理盐水25 mL,注射速率3.5 mL/s.B2组:一期碘普罗胺(0.8 mL/kg)按对比剂注射总量的75％,注射速率4.5 mL/s;二期碘普罗胺按对比剂注射总量的25％+生理盐水按1:1浓度,注射速率4.0 mL/s;三期生理盐水25 mL,注射速率4.5 mL/s.将图像根据5分制评分标准,评分在3分及以上的受检者纳入研究.结果 3种对比剂注射技术的比较显示B2组与A组、B1组对比剂用量有统计学意义(P＜0.05).右心房、左右心室、主动脉根部和冠状动脉密度A组与B1组、B2组比较,右心房与右心室密度差异有统计学意义(P＜0.05).结论 冠状动脉CTA成像采用三期相对比剂优化注射技术,在保证图像质量的基础上,可以减少对比剂用量.     

母牛产后保健对定时输精受胎效果分析

为了把新疆兵团第八师规模化奶牛场生产母牛产间距从(450~500)d缩短到420 d以内,试验采用产后母牛药物综合保健和Ovsynch程序(定时输精技术)同期发情配种处理的方法,大规模同期产后牛进行配种。结果表明产后母牛都能有效的减少和预防胎衣不下、产后高热、成母牛死亡等产后疾病,同时能有效的促进产后母牛子宫的快速恢复、激活卵巢功能和恢复母牛体况。能保证产后母牛胎次配种达到100%受配率、年总受胎率85%~90%以上和年平均产间距缩短到420 d以内。     

医学X线图像配准技术研究进展及其存在的问题

医学X线图像受到探测器面积大小的限制,成像范围有限,对较大器官的扫描无法一次完成.在观察病变部位时,医生需要结合多幅图像来进行诊断或治疗,因此需要对多张影像进行拼接处理.作为图像拼接技术的核心,图像配准技术已被广泛应用于医学成像中,将那些从扫描中获得的多类型信息进行配准从而得到更详细的信息.首先,本文重点综述了目前面向X线图像的比较主流和新兴的配准技术,如基于互信息的配准法,基于特征的配准法和基于变换域的配准法.其次,指出了X线图像配准中存在的影像漂移问题、拍摄角度的限制、非刚性配准仍未成熟、没有绝对的配准评价标准等问题.最后,总结了基于FPGA等硬件的医学图像配准、采用超分辨率重建技术以获取更高质量的待配准图像从而提高图像配准的精度和速度等发展趋势与研究前景.     

Effect of male body mass index on clinical outcomes following assisted reproductive technology: a meta‐analysis

Overweight and obese males might exhibit a great risk of infertility. However, according to the current studies, the association between elevated male body mass index (BMI) and the clinical adverse results after assisted reproductive technology (ART) remains controversial. Hence, we conducted a meta‐analysis to evaluate the effects of raised male BMI on clinical outcomes following ART. PubMed, EMBASE and three Chinese databases were used to identify relevant studies. The primary outcome was clinical pregnancy rate. Secondary outcomes included live birth rate and sperm parameters. A total of 5262 male participants from 10 cohort studies were subjected to meta‐analysis. Results indicated that overweight or obese had no significant impact on clinical pregnancy rate [in vitro fertilisation (IVF): odds ratio (OR), 0.73; 95% confidence interval (CI), 0.39–1.39; intracytoplasmic sperm injection (ICSI): OR, 1.03; 95% CI, 0.92–1.15], live birth rate (IVF: OR, 0.91; 95% CI, 0.78–1.06; ICSI: OR, 1.00; 95% CI, 0.50–1.99) and sperm concentration (SMD, ?0.28; 95% CI, ?0.65 to 0.08) compared with normal weight following IVF/ICSI treatments. Exclusion of any single study and almost all the sensitivity analyses showed that our results were reliable. At present, the role of male BMI in the process of ART is only partly understood and should be further investigated.     

Is the wrong question being asked in infertility research?

A persistent finding is that assisted reproductive technology (ART) is associated with compromised birth outcomes, including higher risks for prematurity, low birthweight, and congenital malformations, even among singletons. Over the past decade, our research group, the Massachusetts Outcome Study of Assisted Reproductive Technology (MOSART), has evaluated pregnancy and birth outcomes among three groups of women, those women treated with ART, those with indicators of subfertility but without ART treatment, and fertile women. We have also explored the influence of infertility-related diagnoses on outcomes for women and infants. Over the course of our research, we have changed our perspective from an original focus on ART treatment parameters as the primary cause of excess morbidity to one centered instead on the underlying infertility-related diagnoses. This paper summarizes the research findings from our group that support this change in focus for infertility-based research from a primary emphasis on ART treatment to greater attention to the contribution of preexisting pathology underlying the infertility and suggests directions for future analyses.     

体外受精/卵胞质内单精子显微注射-胚胎移植技术出生的学龄期儿童内分泌状况的随访研究

目的:探讨通过体外受精/卵胞质内单精子显微注射-胚胎移植(IVF/ICSI-ET)技术出生的学龄期儿童内分泌状况是否与同年龄段自然受孕出生儿童存在差异。方法:选择通过IVF/ICSI-ET出生的6~11岁学龄期儿童(IVF/ICSI组)87例,检测其代谢及内分泌情况,并随机抽取同年龄段自然受孕出生儿童(NC组)74例作为对照。结果:IVF/ICSI组平均血红蛋白浓度(MCHC)(334.59±10.17 g/L vs 330.74±13.58 g/L)、血糖水平(4.57±0.33 mmol/L vs 4.45±0.27 mmol/L)均高于NC组,差异有统计学意义(P0.05)。红细胞数、白细胞数、血小板数、平均红细胞体积(MCV)、红细胞平均血红蛋白量(MCH)、三碘甲状腺原氨酸(T3)、甲状腺素(T4)、促甲状腺素(TSH)、空腹胰岛素(0 h INS)及空腹生长激素(0 h GH)组间差异无统计学意义(P0.05)。对影响MCHC的因素进行多重线性回归,是否为双胎、儿童身高对MCHC有影响;对影响血糖的因素进行多重线性回归,结果是否为试管婴儿、儿童性别、身高对血糖有影响。结论:IVF/ICSI-ET出生儿童内分泌状况与自然妊娠出生儿童无明显差异,空腹血糖(0 h GLU)水平高于自然妊娠出生儿童,但均在正常范围内。     

基因测序在胚胎植入前遗传学诊断应用的研究进展

经过30多年的发展,基因测序技术已从最初的Sanger测序发展至当今以单分子测序为特点的测序。早期的Sanger测序可应用于单基因疾病的检测,但其可检测的通量小、速度慢,逐渐被荧光原位杂交(FISH)、比较基因组杂交(CGH)、芯片检测技术等取代。下一代测序(nextgeneration sequencing,NGS)技术作为胚胎植入前遗传学诊断(preimplataion genetic dignosis,PGD)的新检测手段,不仅能检测染色体非整倍性、染色体结构异常以及单基因疾病,而且精度更高,弥补了芯片检测易受探针影响的缺陷。新近建立的基于N G S的非整倍体测序与连锁分析(mutated allele revealed by sequencing with aneuploidy and linkage analyses,MARSALA)技术可以同时检测染色体疾病和单基因疾病。本文概述了基因测序技术的发展进程及其在PGD中的应用,介绍了包括近年开发的多重退火环状循环扩增(MALBAC)技术和MARSALA在内的NGS技术应用于PGD的优点和局限。     

辅助生殖技术助孕后不同步异位妊娠原因探究及文献回顾

目的:探讨辅助生殖技术(ART)能够降低异位妊娠风险的预防、治疗措施。方法:报道2例国内外少见的不同步异位妊娠病例,并结合近年来相关的5个案例进行回顾性分析。结果:不同步异位妊娠成因复杂,自然受孕及ART助孕都可发生,最迟可发生在初次异位妊娠后1个月左右,且往往需要2次手术治疗。结论:对有相应适应证的患者,输卵管抽芯切除作为预处理或冻融单囊胚移植可降低不同步异位妊娠的发生率;异位妊娠手术处理后1个月左右均需密切监测患者情况,尽早发现不同步异位妊娠病灶并给予及时处理。