Elastography for the differential diagnosis of malignant versus benign testicular lesions: a meta-analysis

Ziwei Lin,Rui Lin,Huaiyu Wu,Linghu Wu,Jieying Zeng,Jinfeng Xu,Fajin Dong 대한초음파의학회 2021 ULTRASONOGRAPHY Vol.40 No.4

Purpose: The aim of this study was to evaluate the value of elastography in the differential diagnosis of benign versus malignant testicular lesions.Methods: The PubMed, Cochrane Library, and Embase databases were searched for relevant studies. The diagnostic accuracy of elastography was evaluated using pooled sensitivity, specificity, likelihood ratio, post-test probability, diagnostic odds ratio, and by summarizing the area under the hierarchical summary receiver operating characteristic (HSROC) curve.Results: Seven studies with 568 lesions were included. The pooled sensitivity and specificity were 87% (95% confidence interval [CI], 81% to 92%) and 81% (95% CI, 65% to 90%), respectively. The pooled estimates of the positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 4.48 (95% CI, 2.37 to 8.47), 0.16 (95% CI, 0.10 to 0.25), and 28.11 (95% CI, 11.39 to 69.36), respectively. The area under the HSROC curve was 90% (95% CI, 88% to 93%).Conclusion: Elastography is useful for assessing the stiffness of testicular lesions and for differentiating benign from malignant lesions. Elastography can be an effective supplement to conventional ultrasonography.

Anti-sparse representation for structural model updating using l∞ norm regularization

Ziwei Luo,Ling Yu,Huan-Lin Liu,Zexiang Chen 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.4

Finite element (FE) model based structural damage detection (SDD) methods play vital roles in effectively locating and quantifying structural damages. Among these methods, structural model updating should be conducted before SDD to obtain benchmark models of real structures. However, the characteristics of updating parameters are not reasonably considered in existing studies. Inspired by the l∞ norm regularization, a novel anti-sparse representation method is proposed for structural model updating in this study. Based on sensitivity analysis, both frequencies and mode shapes are used to define an objective function at first. Then, by adding l∞ norm penalty, an optimization problem is established for structural model updating. As a result, the optimization problem can be solved by the fast iterative shrinkage thresholding algorithm (FISTA). Moreover, comparative studies with classical regularization strategy, i.e. the l2 norm regularization method, are conducted as well. To intuitively illustrate the effectiveness of the proposed method, a 2-DOF spring-mass model is taken as an example in numerical simulations. The updating results show that the proposed method has a good robustness to measurement noises. Finally, to further verify the applicability of the proposed method, a six-storey aluminum alloy frame is designed and fabricated in laboratory. The added mass on each storey is taken as updating parameter. The updating results provide a good agreement with the true values, which indicates that the proposed method can effectively update the model parameters with a high accuracy.

Effect of Gas Sensing Properties by Sn-Rh Codoped ZnO Nanosheets

Ziwei Chen,Zhidong Lin,Mengying Xu,Yuyuan Hong,Na Li,Ping Fu,Ze Chen 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.3

The hierarchically porous Sn-Rh codoped ZnO, Sn-doped ZnO and pureZnO nanosheets have been successfully synthesized through a simplehydrothermal reaction process without any surfactant or template at 180°C. The morphology and composition were carefully characterized by X-raydiffraction, energy dispersive X-ray spectrometer, field emission scanningelectronic microscopy and BET. The gas-sensing testing results indicatedthat the Sn-Rh codoped ZnO nanosheets, with the specific surface area was26.9 m2/g, exhibited enhanced gas-sensing performance compared withthat of pure ZnO and Sn-doped ZnO. The high sensitivity of the sensorbased on Sn-Rh codoped ZnO was 149.38 to 100 ppm ethanol and thedetection limit was less than 5 ppm (5.8). The response and recovery timeswere measured to be ~3 s and ~10 s when exposed to 100 ppm ethanol atthe test temperature of 300°C. The good sensing performance of the Sn-Rhcodoped ZnO sensor indicated that hierarchically porous Sn-Rh codopedZnO could be a promising candidate for highly sensitive gas sensors.

Enhanced Formaldehyde Gas Sensing Properties of ZnO Nanosheets Modified with Graphene

Ziwei Chen,Yuyuan Hong,Zhidong Lin,Li-Ming Liu,Xiao-Wen Zhang 대한금속·재료학회 2017 ELECTRONIC MATERIALS LETTERS Vol.13 No.3

In this study, pure ZnO (ZnO-1, ZnO-2) with two different morphologies, andgraphene doped ZnO-2 (G-ZnO-2) were synthesized using a simplehydrothermal process at 150 °C. The formaldehyde gas sensing performanceof the G-ZnO-2 composite, synthesized by an in-situ method was investigated. The morphologies and the structures of the nanomaterials were characterizedby X-ray diffraction, field emission scanning electronic microscopy, andtransmission electron microscopy. The experimental results indicate that the GZnO-2 based sensor exhibits unique advantages for the sensing offormaldehyde gas at concentrations in the range of 2 to 2000 ppm, such as fastresponse/recovery time and good selectivity, at an optimal workingtemperature of 200 °C. The improved sensing performance of the G-ZnO-2composite indicates that the addition of graphene is effective in improving theformaldehyde sensing performance of ZnO-based sensors.

Multi-strategy structural damage detection based on included angle of vectors and sparse regularization

Huan-Lin Liu,Ling Yu,Ziwei Luo,Zexiang Chen 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.4

Recently, many structural damage detection (SDD) methods have been proposed to monitor the safety of structures. As an important modal parameter, mode shape has been widely used in SDD, and the difference of vectors was adopted based on sensitivity analysis and mode shapes in the existing studies. However, amplitudes of mode shapes in different measured points are relative values. Therefore, the difference of mode shapes will be influenced by their amplitudes, and the SDD results may be inaccurate. Focus on this deficiency, a multi-strategy SDD method is proposed based on the included angle of vectors and sparse regularization in this study. Firstly, inspired by modal assurance criterion (MAC), a relationship between mode shapes and changes in damage coefficients is established based on the included angle of vectors. Then, frequencies are introduced for multi-strategy SDD by a weighted coefficient. Meanwhile, sparse regularization is applied to improve the ill-posedness of the SDD problem. As a result, a novel convex optimization problem is proposed for effective SDD. To evaluate the effectiveness of the proposed method, numerical simulations in a planar truss and experimental studies in a six-story aluminum alloy frame in laboratory are conducted. The identified results indicate that the proposed method can effectively reduce the influence of noises, and it has good ability in locating structural damages and quantifying damage degrees.

Risk of Death in Colorectal Cancer Patients with Multi-morbidities of Metabolic Syndrome: A Retrospective Multicohort Analysis

Qingting Feng,Lingkai Xu,Lin Li,Junlan Qiu,Ziwei Huang,Yiqing Jiang,Tao Wen,Shun Lu,Fang Meng,Xiaochen Shu 대한암학회 2021 Cancer Research and Treatment Vol.53 No.3

Purpose The prevalence of multi-morbidities with colorectal cancer (CRC) is known to be increasing. Particularly prognosis of CRC patients co-diagnosed with metabolic syndrome (MetSyn) was largely unknown. We aimed to examine the death risk of CRC patients according to the multiple MetSyn morbidities.Materials and Methods We identified CRC patients with MetSyn from the electronic medical records (EMR) systems in five independent hospitals during 2006-2011. Information on deaths was jointly retrieved from EMR, cause of death registry and chronic disease surveillance as well as study-specific questionnaire. Cox proportional hazards regression was used to calculate the overall and CRC-specific hazards ratios (HR) comparing MetSyn CRC cohort with reference CRC cohort.Results A total of 682 CRC patients in MetSyn CRC cohort were identified from 24 months before CRC diagnosis to 1 month after. During a median follow-up of 92 months, we totally observed 584 deaths from CRC, 245 being in MetSyn cohort and 339 in reference cohort. Overall, MetSyn CRC cohort had an elevated risk of CRC-specific mortality (HR, 1.49; 95% confidence interval [CI], 1.07 to 1.90) and overall mortality (HR, 1.43; 95% CI, 1.09 to 1.84) compared to reference cohort after multiple adjustment. Stratified analyses showed higher mortality risk among women (HR, 1.87; 95% CI, 1.04 to 2.27) and specific components of MetSyn. Notably, the number of MetSyn components was observed to be significantly related to CRC prognosis.Conclusion Our findings supported that multi-morbidities of MetSyn associated with elevated death risk after CRC. MetSyn should be considered as an integrated medical condition more than its components in CRC prognostic management.

Exploration and Validation of the Performance of Hemoglobin A1c in Detecting Diabetes in Community-Dwellers With Hypertension

Shan-hu Qiu,Ziwei Du,Weiling Li,Juan Chen,Hang Wu,Jingbao Liu,Min Cai,Bei Wang,Haijian Guo,Zi-lin Sun 대한진단검사의학회 2020 Annals of Laboratory Medicine Vol.40 No.6

Background: Diabetes can complicate hypertension management by increasing the risk of cardiovascular disease (CVD) and all-cause mortality. Studies targeting diabetes detection in hypertensive individuals demonstrating an increased risk of diabetes are lacking. We aimed to assess the performance of hemoglobin A1c (HbA1c) and its cut-off point in detecting diabetes in the abovementioned population. Methods: Data from 4,096 community-dwellers with hypertension but without known diabetes were obtained from the Study on Evaluation of iNnovated Screening tools and determInation of optimal diagnostic cut-off points for type 2 diaBetes in Chinese muLti-Ethnic (SENSIBLE) study; these data were randomly split into exploration (70% of the sample) and internal validation (the remaining 30%) datasets. The optimal HbA1c cut-off point was derived from the exploration dataset and externally validated using another dataset from 2,431 hypertensive individuals. The oral glucose tolerance test was considered the gold-standard for confirming diabetes. Results: The areas under the ROC curves for HbA1c to detect diabetes were 0.842, 0.832, and 0.829 for the exploration, internal validation, and external validation datasets, respectively. An optimal HbA1c cut-off point of 5.8% (40 mmol/mol) yielded a sensitivity of 76.2% and a specificity of 74.5%. Individuals who were not diagnosed as having diabetes by HbA1c at 5.8% (40 mmol/mol) had a lower 10-year CVD risk score than those diagnosed as having diabetes (P=0.01). HbA1c≤5.1% (32 mmol/mol) and ≥6.4% (46 mmol/mol) could indicate the absence and presence of diabetes, respectively. Conclusions: HbA1c could detect diabetes effectively in community-dwellers with hypertension.