Physics-Driven CFD Modeling of Complex Anatomical Cardiovascular Flows—A TCPC Case Study

Recent developments in medical image acquisition combined with the latest advancements in numerical methods for solving the Navier-Stokes equations have created unprecedented opportunities for developing simple and reliable computational fluid dynamics (CFD) tools for meeting patient-specific surgical planning objectives. However, for CFD to reach its full potential and gain the trust and confidence of medical practitioners, physics-driven numerical modeling is required. This study reports on the experience gained from an ongoing integrated CFD modeling effort aimed at developing an advanced numerical simulation tool capable of accurately predicting flow characteristics in an anatomically correct total cavopulmonary connection (TCPC). An anatomical intra-atrial TCPC model is reconstructed from a stack of magnetic resonance (MR) images acquired in vivo. An exact replica of the computational geometry was built using transparent rapid prototyping. Following the same approach as in earlier studies on idealized models, flow structures, pressure drops, and energy losses were assessed both numerically and experimentally, then compared. Numerical studies were performed with both a first-order accurate commercial software and a recently developed, second-order accurate, in-house flow solver. The commercial CFD model could, with reasonable accuracy, capture global flow quantities of interest such as control volume power losses and pressure drops and time-averaged flow patterns. However, for steady inflow conditions, both flow visualization experiments and particle image velocimetry (PIV) measurements revealed unsteady, complex, and highly 3D flow structures, which could not be captured by this numerical model with the available computational resources and additional modeling efforts that are described. Preliminary time-accurate computations with the in-house flow solver were shown to capture for the first time these complex flow features and yielded solutions in good agreement with the experimental observations. Flow fields obtained were similar for the studied total cardiac output range (1–3 l/min); however hydrodynamic power loss increased dramatically with increasing cardiac output, suggesting significant energy demand at exercise conditions. The simulation of cardiovascular flows poses a formidable challenge to even the most advanced CFD tools currently available. A successful prediction requires a two-pronged, physics-based approach, which integrates high-resolution CFD tools and high-resolution laboratory measurements.     

生物组织微阵列芯片自动制备仪的研制

介绍了一种新型生物组织微阵列芯片自动制备仪的研制。分析了组织微阵列制备过程中的操作任务和实现目标,进行了制备仪的结构设计和各功能模块研究开发。制备仪从结构上分为蜡块承载定位模块和三工位操作模块,控制系统的组成有操作空间精密定位子系统,组织蜡块图像识别子系统,蜡块打孔填埋作业子系统等。研制成功的制备仪样机具备了图像自动识别、精密定位、自动打孔填埋等功能,实现了生物组织微阵列芯片的自动化制备。     

Laterality of Body Focus and Digital Skin Temperature in Patients with Raynaud''s Disease

The purpose of the present study was to assess the relationship between lateralization of body image and right versus left vasomotor activity. Fifteen right-handed female patients suffering from idiopathic Raynaud's disease demonstrated a relationship between the extent of right lateralization of body image and bilateral digital skin temperature during a controlled temperature stress test. In addition, subjects showing a reliable right side awareness demonstrated more unilateral vasospastic attacks in their right hand than their left hand white subjects showing no clear right lateralization by body image reported more left hand attacks than right hand attacks. These results were taken as consistent with previous work on the relationship between skin conductance and lateralization of body image.     

Impedance-gradient electrode reduces skin irritation induced by transthoracic defibrillation

A new type of disposable external defibrillation electrode has been developed to reduce the skin irritation commonly associated with defibrillation and synchronised cardioversion. This design employs an impedance gradient to reduce the proportion of current delivered to the electrode periphery. The temperature distribution under the new electrode was compared with that of four other types of commercially available electrodes after repeated high-energy biphasic defibrillation discharges to domestic swine. Skin temperature distributions were acquired using non-invasive thermography. Measurements of the maximum temperature rise at each electrode site, taken 3.6s after the fifth defibrillation discharge, demonstrated that the new impedance-gradient electrode produced 50–60% less skin heating than two of the three uniform-impedance electrode designs. Histological examination of erythematous sites excised 24h after defibrillation quantified the associated skin damage using a scoring protocol developed for this study. In contrast to previous studies, histological examinations demonstrated second-degree skin burns following defibrillation. The new electrode design, however, induced 44–46% less skin damage than two of the traditional uniform-impedance electrodes.     

Computerized Digital Imaging Techniques Provided by Digital X-ray Radiogrammetry as New Diagnostic Tool in Rheumatoid Arthritis

Purpose Our study evaluates digital x-ray radiogrammetry (DXR) and Radiogrammetry Kit (RK) as a new diagnostic method for the measurement of disease-related osteoporosis including quantification of joint space narrowing dependent on the severity of rheumatoid arthritis (RA). Materials and Methods A total of 172 unselected patients with RA underwent computerized measurements of bone mineral density (BMD) and metacarpal index (MCI) by DXR, as well as a semiautomated measurement of joint space distances at the metacarpal–phalangeal articulation (JSD-MCP 2–5), both were analyzed from plain radiographs of the nondominant hand. Results Correlations between DXR-BMD and DXR-MCI vs. parameters of RK were all significant (0.34 < R < 0.61; p < 0.01). An expected negative association was observed between RK parameters and the different scoring methods (−0.27 < R < −0.59). The maximum relative decrease in BMD vs. MCI as measured by DXR between the highest and lowest RA severity group was −27.7% vs. −27.5% (p < 0.01) for the modified Larsen Score, whereas the minimal value of relative DXR-BMD and DXR-MCI reduction could be documented for the Sharp Erosion Score (−20.8% vs. −26.8%; p < 0.01). The relative reduction of mean JSD-MCP using RK significantly varied from −25.0% (Sharp Erosion Score) to −41.2% (modified Larsen Score). In addition, an excellent reproducibility of DXR and RK could be verified. Conclusion DXR in combination with RK could be a promising, widely available diagnostic tool to supplement the different scoring methods of RA with quantitative data, allowing an earlier and improved diagnosis and more precision in determining disease progression.     

Extraction of organic acids by ion-pair extraction with tri-n-octylamine - VIII. Identification of synthetic dyes in pharmaceutical preparations

Synthetic dyes were extracted from syrups, oral suspensions, tablets, gelatin capsules, suppositories and granules by ion-pair formation with tri-n-octylamine (TnOA) and back-extracted with perchlorate ions. Identification was performed by TLC on cellulose layers and by reversed phase ion-pair HPLC.     

Digital subtraction angiography (DSA): New perspectives in angiography

Summary Digital subtraction angiography (DSA) has strongly influenced angiographic procedures. Because it is less invasive it has increased the total number of angiographies in all places where it was introduced. The paper gives an introduction to the procedure explaining the roles of digital and subtraction in DSA. It is written from a technical point of view. The examples are taken from and with the DVI system.     

Direct quantitation of antiseptic quaternary ammonium compounds by fast atom bombardment mass spectrometry

The medicinally important quaternary ammonium salts benzyldimethyltetradecylammonium chloride (BDTA), cetylpyridinium chloride and benzethonium chloride, all afford, under fast atom bombardment (FAB) mass spectrometric conditions, abundant and persistent [M---Cl]⁺ species usefully amenable to quantitative analysis with the aid of thioglycerol as a liquid FAB matrix. The use of BDTA as an internal standard allowed a direct, precise and accurate determination of cetylpyridinium and benzethonium chlorides, either as pure samples or in dosage forms, in the concentration range 0.05–2 mg/ml.     

数字医学技术在儿童腹部实质脏器损伤诊治中的临床应用效果

目的:探讨儿童腹部实质脏器损伤诊治中应用数字医学技术的效果。方法:选取2016年1月至2022年8月贵港市人民医院采用数字医学技术指导期间诊治的100例腹部实质脏器损伤患儿作为观察组,另选取2012年1月至2015年12月未采用数字医学技术指导期间诊治的100例腹部实质脏器损伤患儿作为对照组,比较两组患儿中,不同创伤类型患儿在保守治疗中的输血量、住院时间、保守治疗成功率;以及不同创伤类型的患儿中转手术治疗的术中出血量、手术时间及术后并发症情况。结果:选择保守治疗的患儿中,观察组肝损伤、脾损伤、肾损伤患儿的保守治疗成功率均高于对照组,输血量均少于对照组,住院时间均短于对照组,差异均具有统计学意义(P <0.05);中转手术治疗的患儿中,观察组肝损伤、脾损伤、肾损伤患儿的术中出血量均少于对照组,手术时间均短于对照组,差异均具有统计学意义(P <0.05);两组中不同创伤类型患儿的手术并发症发生率比较,差异均无统计学意义(P> 0.05)。结论:数字医学技术应用在儿童腹部实质脏器损伤诊治中,可为治疗方案的选择提供准确的指导,有助于提高治疗方案的效果,改善患儿临床指标,缩短住...