New system for image analysis in nailfold capillaroscopy.

For quantitative evaluation of human TV nailfold capillary microscopy a new semi-automated image-analyzing system called "CapiShape" is presented. Skeletons and boundaries of capillaries are obtained by a special image processing algorithm to describe the shape of capillaries. In addition to conventional parameters such as diameters and loop widths for the size of single capillaries, new non-size parameters related to surface area and the skeletons are calculated. To describe capillary distribution in a nailfold, the ratio of distance between capillaries to its projection in the X axis, and area percentage are indicated. With different operators and different orientations of the camera, the measured differences in diameters and loop widths are smaller than 1.5 microm, and in area percentage smaller than 1.0%. As practical examples, applications of CapiShape to patients with scleroderma showed marked, significant differences in capillary size between patients and controls, patients with diabetes differed significantly in non-size parameters from controls. CapiShape is specially designed for clinical applications, and besides the usual measures new parameters for describing nailfold images may be developed. CapiShape is safe and easy to use for diagnosis, routine examination, and quantitative follow-up studies.     

医学图像多维重建中的插值问题研究进展

插值广泛应用于医学成像和图像多维重建中。本文首先对传统插值方法中基于形状的插值和弹性匹配插值作了比较深入的介绍，然后分析了旋转扫描超声心脏图像插值方法的特点、难点和研究现状，论述了插值和匹配的关系，分析表明准确的旋转扫描插值方法应该是基于匹配的方法，最后讨论了图像插值的几种评价方法。     

Benign overfitting in linear regression

The phenomenon of benign overfitting is one of the key mysteries uncovered by deep learning methodology: deep neural networks seem to predict well, even with a perfect fit to noisy training data. Motivated by this phenomenon, we consider when a perfect fit to training data in linear regression is compatible with accurate prediction. We give a characterization of linear regression problems for which the minimum norm interpolating prediction rule has near-optimal prediction accuracy. The characterization is in terms of two notions of the effective rank of the data covariance. It shows that overparameterization is essential for benign overfitting in this setting: the number of directions in parameter space that are unimportant for prediction must significantly exceed the sample size. By studying examples of data covariance properties that this characterization shows are required for benign overfitting, we find an important role for finite-dimensional data: the accuracy of the minimum norm interpolating prediction rule approaches the best possible accuracy for a much narrower range of properties of the data distribution when the data lie in an infinite-dimensional space vs. when the data lie in a finite-dimensional space with dimension that grows faster than the sample size.     

一种亚像元遥感图像的小波复原方法

为了复原在轨卫星拍摄的退化遥感图像,以达到精确的对地观测的目的,利用交错半个像素的"亚像元"图像进行交错采样,重建成分辨率更高的的网格,然后对新建出的空格点进行小波插值估计.对插值后图像的高频进行中值滤波,融合两幅错半个像元的图像信息,最后复原成一幅地貌信息更丰富、分辨率更高的遥感图像.试验的仿真图像证明了这种小波复原方法的有效性.     

Reproducibility of electromyographic and mechanical parameters of the triceps surae during submaximal and maximal plantar flexions

Introduction: Neuromuscular parameters must be reproducible to examine neuromuscular adaptations in interventional and clinical studies. The reproducibility of neuromuscular parameters for the soleus (SOL), lateral gastrocnemius (LG), and medial gastrocnemius (MG) was assessed over a period of 2 weeks. Methods: Thirteen subjects (27.4 years, 69.5 kg) were tested for numerous electromyographic (e.g., voluntary and electrical evoked EMG) and mechanical (e.g., voluntary activation level) parameters in 3 test sessions. Results: The majority of the data (28 of 34) revealed moderate and substantial reproducibility. H_max20%/M_max20% and V_sup/M_sup were less reproducible in LG than in MG and SOL. Muscle activity and M‐waves did not differ between muscles. The ICC for the mechanical data was >0.79. Conclusions: The H‐reflex during voluntary contraction of the LG should be considered with caution. Mechanical data on muscle activation level are reproducible. The reproducibility of neuromuscular parameters is sufficient for interventional studies. Muscle Nerve 53: 464–470, 2016     

Spinal and supraspinal mechanisms affecting torque development at different joint angles

Introduction: We examined the neural mechanisms responsible for plantar flexion torque changes at different joint positions. Methods: Nine subjects performed maximal voluntary contractions (MVC) at 6 ankle–knee angle combinations [3 ankle angles (dorsiflexion, anatomic position, plantar flexion) and 2 knee angles (flexion, full extension)]. Neural mechanisms were determined by V‐wave, H‐reflex (at rest and during MVC), and electromyography during MVC (RMS), normalized to the muscle compound action potential (V/M_sup, H_max/M_max, H_sup/M_sup and RMS/M_sup) and voluntary activation (VA), while muscle function was assessed by doublet amplitude. Results: MVC and doublet amplitude were significantly lower at plantar flexion (P < 0.01), while VA was significantly lower at dorsiflexion and full knee extension (P < 0.05). V/M_sup and RMS/M_sup were significantly lower at knee extension (P < 0.01), while H_sup/M_sup was not affected by joint angle. Conclusions: These results indicate that joint positions leading to muscle lengthening produce reduced neural drive, due mainly to supraspinal mechanisms. Muscle Nerve 53 : 626–632, 2016     

Creatine supplementation does not alter neuromuscular recovery after eccentric exercise

Introduction: The purpose of this study was to investigate the effects of creatine (CR) supplementation on recovery after eccentric exercise (ECC). Methods: Fourteen men were assigned randomly to ingest 0.3 g/kg of CR or placebo (PL) before and during recovery (48 hours) from 6 sets of 8 repetitions of ECC. Maximal voluntary contraction (MVC), voluntary activation (VA), muscle thickness (MT), electromyography (EMG), contractile properties, and soreness were assessed. Results: MVC, evoked twitch torque, and rate of torque development decreased for both groups immediately after ECC and recovered at 48 hours. MT increased and remained elevated at 48 hours for both groups. Soreness increased similarly for both groups. EMG activation was higher for CR versus PL only at 48 hours. There were no group differences for torque, total work, or fatigue index during ECC. Conclusions: CR supplementation before and during recovery from ECC had no effect on strength, voluntary activation, or indicators of muscle damage. Muscle Nerve 54 : 487–495, 2016     

多层面CT机

对目前商品化的四类多层面CT机进行了比较,给出了多层面CT机部分概念的新内涵,讨论了多层面CT机的性质能量。     

Estimated Worldwide Prevalence of the PI*ZZ Alpha-1 Antitrypsin Genotype in Subjects With Chronic Obstructive Pulmonary Disease

IntroductionThe prevalence of α1-antitrypsin PI*ZZ genotypes in patients with COPD is only partially known. We aimed to estimate this prevalence worldwide.MethodA systematic review of the literature was conducted for studies investigating the prevalence of COPD and the prevalence of severe alpha-1-antitrypsin deficiency (AATD) PI*ZZ genotype. Results are shown in tables and on a whole world interpolation map.ResultsStudies from 48 countries with available data (21 from Europe, 9 from the Americas, 5 from Africa, 11 from Asia and 2 from Australasia) were selected. About 235,000 individuals with PI*ZZ genotypes were accounted: 50% in Europe, 37% in America, 9% in Asia, 3% in Australasia and 1% in Africa. The estimated crude prevalence of COPD in adults older than 40 years was 12.45% in Europe, 13.51% in America, 13.22% in Africa, 11.70% in Asia and 11.86% in Australasia. The highest PI*ZZ weighted average prevalence among COPD subjects (expressed as 1/x [95% confidence intervals]) were found in Northern Europe (395 [252–576]) followed by Western (797 [538–1165]), Southern (944 [600–1475]) and Central Europe (1096 [687–1738]). Outside Europe, high values were found in Australia–New Zealand (1007 [684–1509]), Saudi Arabia (1276 [563–2961]), United States (1298 [1094–1540]), Canada (1482 [1057–2083]) and Thailand (1807 [717–4692]). In the rest of the world, prevalence was significantly lower, especially in vast regions of Asia and Africa where the PI*Z gene is practically non-existent.ConclusionsSevere AATD is associated with a significant number of cases of COPD, especially in Europe, USA, Canada, New Zealand and Australia.