Identification of the haemodynamic environment permissive for plaque erosion

Endothelial erosion of atherosclerotic plaques is the underlying cause of approximately 30% of acute coronary syndromes (ACS). As the vascular endothelium is profoundly affected by the haemodynamic environment to which it is exposed, we employed computational fluid dynamic (CFD) analysis of the luminal geometry from 17 patients with optical coherence tomography (OCT)-defined plaque erosion, to determine the flow environment permissive for plaque erosion. Our results demonstrate that 15 of the 17 cases analysed occurred on stenotic plaques with median 31% diameter stenosis (interquartile range 28–52%), where all but one of the adherent thrombi located proximal to, or within the region of maximum stenosis. Consequently, all flow metrics related to elevated flow were significantly increased (time averaged wall shear stress, maximum wall shear stress, time averaged wall shear stress gradient) with a reduction in relative residence time, compared to a non-diseased reference segment. We also identified two cases that did not exhibit an elevation of flow, but occurred in a region exposed to elevated oscillatory flow. Our study demonstrates that the majority of OCT-defined erosions occur where the endothelium is exposed to elevated flow, a haemodynamic environment known to evoke a distinctive phenotypic response in endothelial cells.

Simulation Model of an Adaptive Control System for a Segmented Deformable Mirror in a Space Telescope and its Metrological Certification

The paper concerns a measurement problem of identifying inadequacy in a mathematical model of an adaptive control system driving segments of a deformable mirror in a large telescope. This is necessary to assess the validity of this model. A dual-axis servo drive unit utilising permanent magnet synchronous machines controls the mirror segments. The servo unit rotates each segment of the deformable mirror with respect to its axis of symmetry and tilts each segment relative to the fixed central reference segment. The paper provides general descriptions of the model structure and the feedback in the current control loop employing phase current measurement and coordinate transformations. We present initial data sets for metrological certification of the model. We used the MMK-stat M software to perform the metrological certification so that we could check empirical equations, determine the scope of application for the model and validate it. The metrological certification allowed us to confirm that the model of an adaptive control system for a segmented deformable telescope mirror is valid, and to find the model structure that ensures a more accurate description of the measurement problem that concerns controlling the spatial position of the object simulated

Dismetría y características posturales en personas con amputación de extremidad inferior y análisis de su alineación protésica

Lower limb amputees (LLAm) with prosthetic limbs get through alignment and leveling processes to assure the correct function of their device. However, errors in this process may led to lower limb asymmetry (LLA). Depending on the magnitude of the LLA there is a greater risk of presenting postural asymmetry, gait disturbances, low back pain, and structural deformities. Therefore, the main objective of this article is to determine LLA and alignment and postural features of people with lower limb (LL) amputation using the software Kinovea. Nowadays there is not much literature about the postural and asymmetry analysis of LLAm. The method followed to calculate the asymmetry was to first do the software calibration with a chosen reference segment, then each leg segment was measured using Kinovea to obtain the absolute difference between them. The angles of knee flexion and alignment were also analyzed with the help of marks previously placed in the subjects’ points of interest. Among the 16 subjects, 8 presented an asymmetry level I, 3 a level II and 5 a level III, in the lateral position. The longest LL of 11 of the 13 unilateral amputees presented the smallest knee flexion angle. The subjects’ knee stability was classified as stable for 7 of them, as unstable for 9 and only 1 subject as extremely stable. The main application of the results obtained would be to use the information to create a database that can be used for future research and as feedback for prosthetists and orthotists.

Imaging Characteristics of Mismatch Lesions: An Angiographic and Intravascular Ultrasound Analysis of 1369 Coronary Lesions

Objectives:To evaluate the angiographic and intravascular ultrasound (IVUS) characteristics of coronary mismatch lesions.Background:Better understanding about the characteristics of mismatch lesions may help to achieve more accurate lesion assessment and, thereby, to improve the outcomes of percutaneous coronary intervention (PCI).Methods:Angiographic and IVUS data from 1369 lesions were analyzed. Mismatch lesion was defined as the difference between proximal and distal reference lumen diameters of ≥1.0 mm or ≥30% of the distal reference lumen diameter.Results:The incidence of mismatch lesions was 20.1% (275/1369). Compared to nonmismatch group, mismatch group had longer lesions (21.3 [6.4] mm vs 18.4 [6.4] mm, P < .001) with smaller minimum lumen diameter (0.87 [0.29] mm vs 1.10 [0.31] mm, P < .001) and more severe diameter stenosis (78.8% [9.2%] vs 66.3% [10.3%], P < .001). On IVUS, mismatch group had larger lumen area (18.7 [5.0] vs 15.8 [5.1] mm2, P < .001) but lower plaque burden at the proximal reference segment (41.0% [9.2%] vs 45.7% [9.9%], P < .001) and smaller lumen area (4.83 [1.89] vs 7.36 [2.89] mm, P < .001) but higher plaque burden at the distal reference segment (42.9% [10.4%] vs 41.4% [10.1%], P = .023). Multivariable logistic regression analysis showed that mismatch lesions were frequently accompanied by diffuse lesions (odds ratio [OR] = 2.50; 95% confidence interval [CI]: 1.83-3.40; P < .001), bifurcation lesions (OR = 5.83; 95% CI: 4.40-7.74; P < .001), and lesions with a low TIMI flow grade (OR = 1.70; 95% CI: 1.08-2.67; P = .022) or severe diameter stenosis (OR = 3.05; 95% CI: 2.10-4.43; P < .001).Conclusions:Mismatch lesions are quite common and characterized by greater lesion complexity compared with nonmismatch lesions. Further studies may be necessary to address the impact of this lesion type on the outcome of PCI.

Evaluation of Anatomical and Functional Hip Joint Center Methods: The Effects of Activity Type, Gender, and Proximal Reference Segment

Accurate hip joint center (HJC) location is critical when studying hip joint biomechanics. The HJC is often determined from anatomical methods, but functional methods are becoming increasingly popular. Several studies have examined these methods using simulations and in vivo gait data, but none has studied high-range of motion activities, such a chair rise, nor has HJC prediction been compared between males and females. Furthermore, anterior superior iliac spine (ASIS) marker visibility during chair rise can be problematic, requiring a sacral cluster as an alternative proximal segment; but functional HJC has not been explored using this approach. For this study, the quality of HJC measurement was based on the joint gap error (JGE), which is the difference in global HJC between proximal and distal reference segments. The aims of the present study were to: (1) determine if JGE varies between pelvic and sacral referenced HJC for functional and anatomical methods, (2) investigate which functional calibration motion results in the lowest JGE and if the JGE varies depending on movement type (gait versus chair rise) and gender, and (3) assess whether the functional HJC calibration results in lower JGE than commonly used anatomical approaches and if it varies with movement type and gender. Data were collected on 39 healthy adults (19 males and 20 females) aged 14–50 yr old. Participants performed four hip “calibration” tests (arc, cross, star, and star-arc), as well as gait and chair rise (activities of daily living (ADL)). Two common anatomical methods were used to estimate HJC and were compared to HJC computed using a published functional method with the calibration motions above, when using pelvis or sacral cluster as the proximal reference. For ADL trials, functional methods resulted in lower JGE (12–19 mm) compared to anatomical methods (13–34 mm). It was also found that women had significantly higher JGE compared to men and JGE was significantly higher for chair rise compared to gait, across all methods. JGE for sacrum referenced HJC was consistently higher than for the pelvis, but only by 2.5 mm. The results indicate that dynamic hip range of movement and gender are significant factors in HJC quality. The findings also suggest that a rigid sacral cluster for HJC estimation is an acceptable alternative for relying solely on traditional pelvis markers.

clonotypeR--high throughput analysis of T cell antigen receptor sequences

Motivation The T cell receptors are expressed as millions of different rearrangements. Amplified as a complex mixture of PCR products, they can be sequenced directly on next-generation instruments without the need for cloning. This method is increasingly used to characterize, quantify and study these highly diverse receptors. Results We present here clonotypeR, a software package to identify and analyze antigen receptors from high-throughput sequence libraries. ClonotypeR is designed to process, organize and analyze very large numbers of sequences, in the order of millions, typically produced by Roche 454 or Illumina instruments, and is made of two parts. The first contains shell scripts and reference segment sequences to produce a data file where each line represents a the detection of a clonotype in a sequence read. The second part is a R module available from Bioconductor, to load and filter the data, and prepare clonotype abundance tables ready for analysis with third-party tools for differential representation analysis, sample clustering, etc. To analyze clonotype data at the nucleotide level, we introduce unique clonotype identifiers based on those developed by Yassai et al. (2009), that we corrected to avoid identifier collisions. Availability http://clonotyper.branchable.com (CC0 license).