Machine-learning models for activity class prediction: A comparative study of feature selection and classification algorithms

PurposeMachine-learning (ML) approaches have been repeatedly coupled with raw accelerometry to classify physical activity classes, but the features required to optimize their predictive performance are still unknown. Our aim was to identify appropriate combination of feature subsets and prediction algorithms for activity class prediction from hip-based raw acceleration data.MethodsThe hip-based raw acceleration data collected from 27 participants was split into training (70 %) and validation (30 %) subsets. A total of 206 time- (TD) and frequencydomain (FD) features were extracted from 6-second non-overlapping windows of the signal. Feature selection was done using seven filter-based, two wrapper-based, and one embedded algorithm, and classification was performed with artificial neural network (ANN), support vector machine (SVM), and random forest (RF). For every combination between the feature selection method and the classifiers, the most appropriate feature subsets were found and used for model training within the training set. These models were then validated with the left-out validation set.ResultsThe appropriate number of features for the ANN, SVM, and RF ranged from 20 to 45. Overall, the accuracy of all the three classifiers was higher when trained with feature subsets generated using filter-based methods compared with when they were trained with wrapper-based methods (range: 78.1 %–88 % vs. 66 %–83.5 %). TD features that reflect how signals vary around the mean, how they differ with one another, and how much and how often they change were more frequently selected via the feature selection methods.ConclusionsA subset of TD features from raw accelerometry could be sufficient for ML-based activity classification if properly selected from different axes.     

应用 σ度量对深圳市龙华区三家综合医院临床生化检验结果互认的评价研究

目的　探讨 σ度量在深圳市龙华区三家综合医院临床生化检验结果互认中的应用价值。方法　收集三家医院 2019年广东省临检中心常规化学，特殊蛋白前两次的室间质评（ EQA）样本，经混匀并分割成比对样本送至各评价实验室进行检测；以卫生部临检中心（ NCCL)标准和生物学变异导出的允许总误差（ TEa%）为质量规范，通过加权法计算出各项目 2019年 1～ 6月期间室内质控在控数据的不精密度，以 2018年参加卫生部室间质评（ EQA）数据作为偏倚（ bias%）来源，计算三家医院 29个检验项目的 σ度量值并进行性能评价，利用质量目标指数（ QGI)提出改善方法；将评价项目的 σ度量值与直接比对试验进行比较，通过统计分析确定 σ截断值（ cut-off）。结果　①三家医院 29个生化项目的性能并不一致，将项目中、高值的 σ值进行配对 t检验，其 t值分别为 2.28，3.01和 0.74，按 α =0.05水准判断得出医院 A与 B，医院 A与 C间的性能差异有统计学意义，医院 B与 C间的性能差异无统计学意义，医院 A项目性能要优于 B，C医院。评估的 87个项目中有 53项 σ平均值 <6，根据 QGI判断，3个项目需优先改善准确度，10个项目需同步改善准确度和精密度，另 40个项目需优先改善精密度。②对医院间项目比对通过率进行配对 χ2检验，其 χ2分别为 5.33，6.25和 2.5，按α=0.05水准判断， B与 A医院比对通过率低于 C与 A医院、 C与 B医院，差异有统计学意义； C与 A医院比对通过率跟 C与 B医院差异无统计学意义。③将 σ度量值与直接比对试验进行比较，经配对 χ2检验，当 σ cut-off值取≥ 2σ， ≥ 3σ，≥ 4σ，≥ 5σ和≥ 6σ时，其 χ2分别为 7.20，0.00，9.09，15.06和 16.06，按 χ20.05，1=3.84，α=0.05水准判断，当σcut-off值取≥ 3σ时，两种比对方法的差异无统计学意义。结论　σ度量值可以单独用于评价医院间生化检验结果的互认，在判断项目是否具有可比性时，可考虑将 σ cut-off值设为≥ 3σ。     

Telangiectasia macularis eruptiva perstans: diagnóstico dermatoscópico

IntroductionTelangiectasia macularis eruptiva perstans (TMEP) is a rare cutaneous mastocytosis, characterised by erythematous and/or brown macula in which telangiectasia are identified. The diagnosis is based on the clinical state of the lesions and on histopathology; however dermoscopy is an important diagnostic tool, revealing a very characteristic reticular vascular pattern.MethodologyA clinical examination, dermatoscopy, photographic follow-up, and histological study were performed on 5 patients with erythematous brown spots on the neck and V of the neckline, and were seen in this Centre between 2008 and 2018. A polarised light dermatoscope was used on lesion and the skin around it. All patients had a 4 mm punch biopsy of the affected skin, and the slices were stained with haematoxylin-eosin and Giemsa.ResultsThe dermatoscopy of the 5 patients showed a retiform vascular pattern with surrounding and crossing yellow spots corresponding to the follicular sebaceous glands, with few hairs. The skin around the lesion did not show any of these changes. In all patients, biopsy with haematoxylin-eosin corroborated the diagnosis of mastocytosis type TMEP. The location of the disease in the 5 patients was in the neck and V of the neckline.ConclusionsDermatoscopy helps in the diagnosis of TMEP by demonstrating that the retiform telangiectatic vascular pattern is a constant finding in all affected patients, and this is supported by the dermoscopic-histological findings. It also makes it possible to differentiate with other erythematous skin disease, and with other disorders that dermatoscopically exhibit retiform patterns.     

出生缺陷监测进展

利用科学、合理的监测手段对出生缺陷进行长期、持续的动态观察,有助于及时获悉缺陷发病率和疾病顺位的变化趋势,分析原因,为制定出生缺陷防控策略措施提供科学依据。本文综述了国内外出生缺陷的监测模式、监测病种和监测期限的工作进展。     

Neurofeedback and neuroplasticity of visual self-processing in depressed and healthy adolescents: A preliminary study

Adolescence is a neuroplastic period for self-processing and emotion regulation transformations, that if derailed, are linked to persistent depression. Neural mechanisms of adolescent self-processing and emotion regulation ought to be targeted via new treatments, given moderate effectiveness of current interventions. Thus, we implemented a novel neurofeedback protocol in adolescents to test the engagement of circuits sub-serving self-processing and emotion regulation.MethodsDepressed (n = 34) and healthy (n = 19) adolescents underwent neurofeedback training using a novel task. They saw their happy face as a cue to recall positive memories and increased displayed amygdala and hippocampus activity. The control condition was counting-backwards while viewing another happy face. A self vs. other face recognition task was administered before and after neurofeedback training.ResultsAdolescents showed higher frontotemporal activity during neurofeedback and higher amygdala and hippocampus and hippocampi activity in time series and region of interest analyses respectively. Before neurofeedback there was higher saliency network engagement for self-face recognition, but that network engagement was lower after neurofeedback. Depressed youth exhibited higher fusiform, inferior parietal lobule and cuneus activity during neurofeedback, but controls appeared to increase amygdala and hippocampus activity faster compared to depressed adolescents.ConclusionsNeurofeedback recruited frontotemporal cortices that support social cognition and emotion regulation. Amygdala and hippocampus engagement via neurofeedback appears to change limbic-frontotemporal networks during self-face recognition. A placebo group or condition and contrasting amygdala and hippocampus, hippocampi or right amygdala versus frontal loci of neurofeedback, e.g. dorsal anterior cingulate cortex, with longer duration of neurofeedback training will elucidate dosage and loci of neurofeedback in adolescents.     

The impact of canister geometry on chemical biological radiological and nuclear filter performance: A computational fluid dynamics analysis

Steady-state axisymmetric simulations using the Reynolds-Averaged Navier-Stokes equations have been carried out in order to optimize the performance of a Chemical, Biological, Radiological, and Nuclear (CBRN) canister filter for its use in a powered air-purifying respirator (PAPR). Alterations have been made to the shape of the canister, the spacing of the rear wall of the canister with regard to the carbon filter, and the bracketing between (i) the particulate filter and the carbon bed and (ii) the carbon bed and the canister wall. The pressure drops across the canister and the residence time distribution at the rear of the carbon bed have been analyzed in detail based on an extensive parametric analysis involving the aforementioned variations. It has been demonstrated that the non-uniform porosity profile of the carbon bed resulted in alternating regions of high and low velocity close to the canister wall, providing a possible route for breakthrough. Designs, which included a bracket at the rear of the carbon bed, blocked this route and consequently had a longer minimum mean residence time than those, which did not. It has also been shown that the spacing between the carbon bed and the canister rear wall had a large impact on both residence time and pressure drop. In cases where the carbon backed directly onto the canister rear wall flow in the axial direction from the outside wall toward the canister axis resulted in far greater pressure drop and a reduction in minimum mean residence time within the carbon bed.     

Participation profiles in domestic life and peer relations as experienced by adolescents with and without impairments and long-term health conditions

Purpose: To investigate how individual and environmental factors relate to self-reported participation profiles in adolescents with and without impairments or long-term health conditions. Methods: A person-oriented approach (hierarchical cluster analysis) was used to identify cluster groups of individuals sharing participation patterns in the outcome variables frequency perceived importance in domestic life and peer relations. Cluster groups were compared using one-way analysis of variance (ANOVA). Results: A nine-cluster solution was chosen. All clusters included adolescents with impairment and long-term health conditions. Perceived importance of peer relations was more important than frequent attendance in domestic-life activities. Frequency of participation in dialogues and family interaction patterns seemed to affect the participation profiles more than factors related to body functions. Conclusion: Type of impairment or long-term health condition is a weaker determinant of membership in clusters depicting frequency and perceived importance in domestic life or peer relations than dialogue and family environment.     

原料配比对胆南星成分及药效影响

目的考察原料配比对胆南星成分和药效作用的影响。方法采用UPLC⁃MS/MS法及负离子多反应监测(MRM)模式进行不同原料配比的胆南星中鹅去氧胆酸、猪去氧胆酸、猪胆酸、牛磺鹅去氧胆酸、牛磺猪去氧胆酸、甘氨鹅去氧胆酸的含有量测定。胆南星甲醇溶液的分析采用Waters Acquity UPLC BEH C18柱(50 mm×2.1 mm,1.7μm);流动相乙腈⁃0.1%甲酸水,梯度洗脱;体积流量0.25 mL/min;柱温45℃。药效学采用大鼠酵母致热实验、小鼠气管段酚红法和小鼠氨水引咳实验考察不同原料配比对胆南星药效作用影响。结果不同原料配比的胆南星中胆汁酸含有量差异明显,胆汁占原料比大于1∶1时,胆南星的解热、祛痰、止咳作用有统计学差异(P<0.05),胆汁占配比为1∶2时解热、祛痰作用较差(P>0.05)。结论胆汁比例对胆南星的成分和药效作用有显著影响,胆汁占原料比不应低于1∶1。