Evaluating the role of strain ratio elastography in determining malignancy potential and calculating objective BIRADS US scores using ultrasonography and elastography features

Purpose: The aims of this study were, firstly, to evaluate solid breast masses based on their malignancy potential and to determine whether the strain elastography ratio (SER) can contribute to classical grey-scale ultrasonography findings, and secondly, to define objective BIRADS US scores using ultrasound (US) and SER findings. Material and methods: A total of 280 patients and 297 solid breast masses were evaluated using sonographic and elastographic data. The SER was measured for each lesion. Results: The positive predictive values (PPV) for each criterion was calculated to be between 35% and 83.3%. The lowest PPV was obtained from hypoechogenicity (35%) and the highest PPV was obtained for anti-parallel features (83.3%). The difference between the mean SER of benign and malignant lesions was statistically significant. After ROC analysis, the SER cut-off value was calculated to be 3.1 for determining if the mass was benign or malignant. Mass scores were calculated for each solid breast mass based on positive predictive values, and BIRADS US score was defined as the sum of mass scores. Conclusions: SER findings can be used as malignancy criteria in evaluating solid breast masses. BIRADS US score can be objectively determined based on US and elastography features instead of doing subjective scoring. As an additional result, all solid breast masses have the possibility to be malignant, even though US and elastography findings indicate the opposite

Investigation of the Physical Characteristics of Polypropylene Meltblown Nonwovens Under Varying Production Parameters

WOS: 00038742600001

Evaluation of diagnostic value of conventional and color Doppler ultrasound with elastography strain ratios in differentiation between benign and malignant lymph nodes

Introduction: The aim of this study was to evaluate the diagnostic value of conventional ultrasonography (USG) and color Doppler ultrasonography (CDU) with elastography strain ratios (ESR) in discrimination between benign and malignant lymphatic nodes. Material and methods: Two hundred and forty-seven patients (252 lymph nodes) were included in this study. USG and CDU with ESR were performed. Materials were obtained by using fine-needle or vacuum-assisted aspiration methods depending on the site and condition of lymph nodes. The χ2 test and Student’s t-test were used for comparisons. Results: Ninety-two of 252 (36.5%) lymph nodes were malignant, and 160 (63.5%) were benign. Short axis, S/L ratio, presence or absence of the fatty hilum and extra-hilar vascularity were valuable, statistically significant indicators of malignancy. In contrast, long axis and ESR were not significant indicators of malignancy. The short axis cut-off value was calculated to be 12 mm and the S/L ratio cut-off value was calculated to be 1. Conclusions: Long axis of lymph nodes and strain ratios cannot be used as malignancy criteria, and their use is controversial despite the fact that some studies have found them valuable. On the other hand, our results support common knowledge that the short axis, S/L ratio, absence of the fatty hilum, and extrahilar vascularity are significant indicators

Evaluating qualitative and quantitative computerized tomography indicators of chronic obstructive pulmonary disease and their correlation with pulmonary function tests

Background: With increasingly aging populations, chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death today. Emphysematous changes, an important component of the disease, must be determined on HRCT, either qualitatively or quantitatively. The purpose of this study was to evaluate features that help determine emphysematous changes and correlate them with respiratory function tests (RFTs). Material/Methods: A total of thirty COPD patients and a control group of the same size, matched for age, were included in the study. The mean lung parenchyma density values on inspiration and expiration, visual HRCT scores, and pulmonary function tests were obtained. IBM SPSS statistical software (version 22) was used to perform correlation analysis (Pearson's coefficient) and the Mann-Whitney U test. Results: The most valuable RFTs for determining emphysematous changes were DLCO, FEV1, and FEV1/FVC, in that order. Quantitative measures of the mean lung density had the highest correlation with coefficient on expiration. Conclusions: As regards the comparison between objective and subjective density values, the HRCT-based visual density values are satisfactory. On the other hand, the best assessment can be performed with the use of mean density values on expiration. DLCO, FEV1, and FEV1/FVC were found to be valuable parameters in determining parenchymal changes

Enhancement of the interface of friction welded steel-aluminium joints

Lightweight multi-material components are of great importance for the transport industry. Not only the component’s weight can be decreased, but also its local properties can be adapted to different loading profiles. Tailored Forming is a novel concept for producing multi-material components. By using a joining process, the creation of a bond between different materials takes place in the first step of the process chain. In the subsequent steps, multi-material workpieces are processed in their joined state while maintaining or improving the joint strength. This study focuses on steel-aluminium joints, which were created by friction welding and further processed by induction heating and impact extrusion. A counter pressure superposition mechanism was implemented in the extrusion tooling to control the stress state during plastic deformation. Flow behaviours of steel and aluminium are largely different at a given temperature, which necessitates a near step-function temperature distribution in the hybrid billet to obtain matching flow stresses. An inductive heating strategy was developed which led to a temperature gradient in the billets before extrusion. Extruded billets were analysed by destructive testing methods and metallography. The bond could be maintained after extrusion when counter pressure superposition was used; but no improvement could be obtained. Without counter force superposition, however, cracks were observed in the joining interface and the joint strength decreased. This paper discusses the aforementioned findings in the current process design and makes suggestions on how the involved processes should be reconfigured to improve the joint strength. © 2020, The Author(s)

Determining the musculoskeletal problems of academicians who transitioned to distance education during the COVID-19 pandemic

Background: Musculoskeletal disorders are a significant public health issue that negatively affects individuals and society both socially and economically, and increases the cost of care and cure. Objective: This study aimed to determine the musculoskeletal problems and risk factors of academicians who transitioned to provide distance education during the COVID-19 pandemic. Methods: The population of this descriptive cross-sectional study included academicians who worked in two public universities in Turkey. Ethical committee approval and institutional permissions were obtained between 1 and 28 February 2021. Data were collected using a personal information form, the Work Environment Evaluation Questionnaire, and the Musculoskeletal Pain Intensity Assessment Questionnaire. The data were analyzed using the number, percentage, independent group t-test, ANOVA test, and linear regression analysis (forward method). The analysis was interpreted at the 95% confidence level and 0.05 error margin. Results: Of the academicians, 78% were women, 54.6% were married, 80.6% did not regularly exercise, and 73.5% had more workload during the distance education period. Academicians mostly experienced discomfort about their eyes, necks, and waists, and an increase at a significant level was detected in their musculoskeletal system problems during the distance education period. Increasing workload, duration of mobile phone use, active time, having an ergonomic chair, and gender predicted the musculoskeletal system pain intensity by 20%. Conclusion: Musculoskeletal system problems are a significant public health issue. Academicians should be informed and consulted for the protection of musculoskeletal system health during the distance education period

Numerical investigations on the influence of the weld surface and die geometry on the resulting tensile stresses in the joining zone during an extrusion process

Bulk metal components are often used in areas which are subjected to very high loads. For most technical components, a distinction between structural and functional areas can be made. These areas usually have very different loading profiles, sometimes with contradictory requirements. Nevertheless, nowadays almost only monomaterials are used for the production of bulk metal components. With increasing requirements towards more and more efficient products with lower weight, compact design and extended functionality, these materials are reaching their material-specific limits. A significant increase of product quality and economic efficiency can be expected exclusively with locally adapted properties by combining different materials within one component. In this regard, the focus of this contribution is the production of a hybrid pinion shaft made of the material combination steel (37CrS4) and aluminium (AW6082). The tool concept for extrusion of the hybrid preform, the simulation-based design of the forming process as well as the material characterisation are presented. With the help of the FE-simulation, different serially arranged semi-finished component geometries were investigated in order to minimise the occurring tensile stresses in the component during the extrusion process to prevent failure during forming

Numerical investigations regarding a novel process chain for the production of a hybrid bearing bushing

This contribution deals with the numerical investigations to develop a novel process chain for hybrid solid components using Tailored Forming. For manufacturing a hybrid bearing bushing, co-extrusion is the first step to produce hybrid semi-finished workpieces followed by a die forging process, machining processes and hardening. Combining aluminium with steel, compounds with wear-resistant functional surfaces and reduced weight are realised. Numerical simulations are a decisive part of the process chain design, for example to determine suitable process parameters for the co-extrusion process and to predict the thickness of intermetallic phases in the joining zone using a macroscopic phenomenological model. A numerical design including a tool analysis of the die forging process was carried out taking the experimentally determined material properties and the temperature profile after inductive heating into account. Additionally, the damage and fatigue behaviour of the polycrystalline material of the joining zone are modelled at the microstructure level. Moreover, a new discretization scheme, namely the virtual element method, which is more efficient at grain level, is developed regarding a crystal plasticity framework. Numerical simulations are used to develop inductive heating strategies for the forming process and for the design of the inductive hardening of the functional surface at the end of the process chain. In order to investigate the performance of this hybrid machine element under application-oriented conditions, a contact simulation is linked with a statistical damage model to calculate the bearing fatigue. In this study, a general overview of the individual process steps is given and results of the respective models are presented. © 2020, The Author(s)

Brain clocks capture diversity and disparities in aging and dementia across geographically diverse populations

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