38 research outputs found

    A curved shell finite element for the geometrically non-linear analysis of box-girder beams curved in plan

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    A four-noded curved shell finite element for the geometrically non-linear analysis of beams curved in plan is introduced. The structure is conceived as a sequence of macro-elements (ME) having the form of transversal segments of identical topology where each slice is formed using a number of the curved shell elements which have 7 degrees of freedom (DOF) per node. A curved box-girder beam example is modelled using various meshes and linear analysis results are compared to the solutions of a well-known computer program SAP2000. Linear and non-linear analyses of the beam under increasing uniformly distributed loads are also carried out. In addition to box-girder beams, the proposed element can also be used in modelling open-section beams with curved or straight axes and circular plates under radial compression. Buckling loads of a circular plate example are obtained for coarse and successively refined meshes and results are compared with each other. The advantage of this element is that curved systems can be realistically modelled and satisfactory results can be obtained even by using coarse meshes

    Business analytics in industry 4.0: a systematic review

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    Recently, the term “Industry 4.0” has emerged to characterize several Information Technology and Communication (ICT) adoptions in production processes (e.g., Internet-of-Things, implementation of digital production support information technologies). Business Analytics is often used within the Industry 4.0, thus incorporating its data intelligence (e.g., statistical analysis, predictive modelling, optimization) expert system component. In this paper, we perform a Systematic Literature Review (SLR) on the usage of Business Analytics within the Industry 4.0 concept, covering a selection of 169 papers obtained from six major scientific publication sources from 2010 to March 2020. The selected papers were first classified in three major types, namely, Practical Application, Reviews and Framework Proposal. Then, we analysed with more detail the practical application studies which were further divided into three main categories of the Gartner analytical maturity model, Descriptive Analytics, Predictive Analytics and Prescriptive Analytics. In particular, we characterized the distinct analytics studies in terms of the industry application and data context used, impact (in terms of their Technology Readiness Level) and selected data modelling method. Our SLR analysis provides a mapping of how data-based Industry 4.0 expert systems are currently used, disclosing also research gaps and future research opportunities.The work of P. Cortez was supported by FCT - Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. We would like to thank to the three anonymous reviewers for their helpful suggestions

    Effect of Sc Addition on the Microstructure and Mechanical Properties of Melt-Spun Al-10Ni Alloys

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    In the present work, rapidly solidified Al-10Ni-XSc (X = 0, 1 and 2) alloys were fabricated by melt spinning under Ar atmosphere. The Effects of Sc on the microstructural and thermal properties and microhardness values were investigated by scanning electron microscopy (SEM), X-ray diffractometer (XRD) and a Vickers microhardness tester. Experimental results revealed that the addition of 2 wt. % Sc to melt-spun Al-10Ni alloys changed their brittle nature and hindered formation of cracks. The addition of Sc to melt-spun Al-10Ni alloys also changed the morphology of Al3 Ni intermetallics from an acicular/needle – like to a rounded particle-like structure and led to reduction in their size. Formation of the metastable Al9 Ni2 phase was observed due to the higher constitutional undercooling caused by Sc addition. A considerable improvement in microhardness value (from 95. 9 to 230. 1 HV) was observed with the addition of Sc

    Factors influencing hemoglobin variability and its association with mortality in hemodialysis patients

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    Purpose. We aimed to investigate the factors influencing hemoglobin variability with inflammatory and nutritional parameters and its associations with all-cause mortality among hemodialysis patients. Methods. One hundred and sixty-nine patients during the entire 12 months were enrolled into the study. Fasting plasma glucose, creatinine, calcium, phosphorus, alkaline phosphatase, parathyroid hormone (PTH), C-reactive protein (CRP), serum iron, serum iron-binding capacity, and transferrin saturation were analyzed. We defined six groups: low, target range, high, low-Amplitude fluctuation with low hemoglobin levels, low-Amplitude fluctuation with high hemoglobin levels, and high-Amplitude fluctuation. Body mass index (BMI), malnutrition-inflammation score (MIS), and Charlson Comorbidity Index were evaluated. Results. Hemoglobin variability was significantly correlated with age, platelet count, and number of hospitalization instances and inversely correlated with erythropoietin dose per body surface area. The coefficient of variation of hemoglobin showed a correlation with MIS and ferritin. The absolute level of hemoglobin showed a negative correlation between PTH, CRP, MIS, number of hospitalization instances and a positive correlation with albumin and BMI. High, low, and target-range groups showed survival advantage compared to the other three groups. In regression analysis, age, CRP levels, MIS, and BMI were the predictors of mortality. Conclusion. Inflammation and duration of anemia were the major predictors of hemoglobin variability. High-Amplitude fluctuation predicts high mortality; on the contrary low-Amplitude fluctuations is related to better survival. MIS was independently associated with mortality. This trial is registered with NCT03454906. © 2018 Zeynep Bal et al

    Detection of insulin resistance in Turkish adults: A hospital-based study

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    PubMedID: 12630938Aim: The aim of the present study was to investigate the usefulness of insulin sensitivity check indices in our hospital population. Methods: Both HOMA (insulin X glucose in mmol/l/22.5) and QUICKI (1/log insulin in µu/ml + log glucose in mg/dl) indices were calculated from fasting values in 1774 subjects from the medical records of Baskent University Adana Hospital. Results: Subjects with diabetes, hyperlipidaemia and central obesity were characterized by significantly higher HOMA and lower QUICKI indices than those of healthy subjects. A fall in the QUICKI index (0.3469 ± 0.028 in healthy subjects and 0.3247 ± 0.025 in non-obese diabetics) as well as an increase in HOMA index (2.24 ± 1.26 in healthy subjects and 3.59 ± 2.08 in non-obese diabetics) corresponded to metabolic and clinical manifestations of insulin resistance in various groups of subjects. Age, low HDL cholesterol, male sex, type 2 DM and hypertension were independent risk factors for CAD. Age, male sex, waist circumference and CAD were found to be risk factors for hypertension. Fasting insulin and glucose levels contain sufficient information to assess insulin sensitivity over a wide range in a diverse population. The following can be accepted as mean values to assess insulin resistance in our hospital population: 0.3469 ± 0.028 for the QUICKI index and 2.24 ± 1.26 for the HOMA index. Conclusions: HOMA and QUICKI indices are simple and reproducible methods for determining insulin sensitivity in humans

    Investigation of schizophrenic patients from Istanbul, Turkey for the presence of West Nile virus

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    Association of some neurotropic viruses like Borna Disease virus and Herpes virus with schizophrenia is better explained. However, the role of West Nile virus (WNV) infection in schizophrenia is not well documented. Therefore, this study was performed to investigate possible association between schizophrenia and presence of antibodies and WNV RNA in schizophrenic patients. For this, 200 blood samples from patients with schizophrenia and 200 from control groups were collected in Istanbul, Turkey. WNV RNA was not detected in any of the 200 patients and 200 controls analyzed by real-time RT-PCR. One hundred and twelve sera of schizophrenic patients and 162 of controls were analyzed for the presence of IgG antibodies to WNV by a commercial IgG-ELISA (Euroimmun, Germany). Antibodies to WNV were detected in 6 schizophrenic patients and 5 controls. ELISA positive patients had antipsychotic therapy. The difference between groups in terms of seropositivity to WNV was not statistically significant (p = 0.887, p = 0.148). Known symptoms of schizophrenia were observed in these patients, and interestingly majority had close contact to cats in the past and come from agricultural area of Turkey where potential area of mosquitoes and bird habitat. In conclusion, the results of this study show that antibodies to WNV in people do not seem to be associated with schizophrenia. However, detecting antibodies to WNV in schizophrenic patients suggests that WNV infection should be considered in endemic areas as it may play role in psychiatric diseases

    GLP-1 receptor agonists synergize with DYRK1A inhibitors to potentiate functional human β cell regeneration.

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    Glucagon-like peptide-1 receptor (GLP1R) agonists and dipeptidyl peptidase 4 inhibitors are widely prescribed diabetes drugs due to their ability to stimulate insulin secretion from remaining β cells and to reduce caloric intake. Unfortunately, they fail to increase human β cell proliferation. Small-molecule inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) are able to induce adult human β cell proliferation, but rates are modest (~2%), and their specificity to β cells is limited. Here, we provide evidence that combining any member of the GLP1R agonist class with any member of the DYRK1A inhibitor class induces a synergistic increase in human β cell replication (5 to 6%) accompanied by an actual increase in numbers of human β cells. GLP1R agonist-DYRK1A inhibitor synergy required combined inhibition of DYRK1A and an increase in cAMP and did not lead to β cell dedifferentiation. These beneficial effects on proliferation were seen in both normal human β cells and β cells derived from individuals with type 2 diabetes. The ability of the GLP1R agonist-DYRK1A inhibitor combination to enhance human β cell proliferation, human insulin secretion, and blood glucose control extended in vivo to studies of human islets transplanted into euglycemic and streptozotocin-diabetic immunodeficient mice. No adverse events were observed in the mouse studies during a 1-week period. Because of the relative β cell specificity of GLP1R agonists, the combination provides an improved, although not complete, degree of human β cell specificity
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