12 research outputs found

    Multi-scale analysis of fretting fatigue in heterogeneous materials using computational homogenization

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    This paper deals with modeling of the phenomenon of fretting fatigue in heterogeneous materials using the multi-scale computational homogenization technique and finite element analysis (FEA). The heterogeneous material for the specimens consists of a single hole model (25% void/cell, 16% void/cell and 10% void/cell) and a four-hole model (25% void/cell). Using a representative volume element (RVE), we try to produce the equivalent homogenized properties and work on a homogeneous specimen for the study of fretting fatigue. Next, the fretting fatigue contact problem is performed for 3 new cases of models that consist of a homogeneous and a heterogeneous part (single hole cell) in the contact area. The aim is to analyze the normal and shear stresses of these models and compare them with the results of the corresponding heterogeneous models based on the Direct Numerical Simulation (DNS) method. Finally, by comparing the computational time and % deviations, we draw conclusions about the reliability and effectiveness of the proposed method

    Mousterian Lithic Technology: An Ecological Perspective, by Steven L. Kuhn, Princeton University Press, 1995

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    Data originating in old excavations are often regarded by archaeologists as being of poor quality or even unusable. Such assemblages lack the stratigraphic and temporal resolution of material acquired by modern excavations and are the product of research projects designed for the investigation of issues profoundly different from those concerning modem researchers. Steven Kuhn's Mousterian lithic Technology demon­strates that this kind of data (in this case coming from 40-plus-year-old excavations) can be successfully incorporated into current research agendas, as long as one uses them for addressing research questions appropriate to the resolution of the data, in this case human behavioural changes on an evolutionary scale. Kuhn bypasses the debate over the biological and/or cultural continuity vs. discontinuity between Neander­thals and modern humans. He argues convincingly that archaeological research will benefit from a disentaglement with the anthropological and the genetic discussions. He maintains that Mousterian material culture and behaviour deserve to be studied in their own right as successful adaptations that persisted over at least 200,000 years, rather than as those replaced by modern human behaviour

    Christ in Flanders [music] : song /

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    C7130 (Publisher number). For voice and piano.; "No. 1 in B-flat".; Imprint from overpasted label. Originally published: London: Chappell ; New York: Chappell-Harms.; Pl. no.: C7130.; Also available online http://nla.gov.au/nla.mus-an6056302; MUS: N, MUSM153161

    CD28null and Regulatory T Cells Are Substantially Disrupted in Patients with End-Stage Renal Disease Due to Diabetes Mellitus

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    Background: End-stage renal disease (ESRD) is associated with alterations in T-cell immunity, including increased CD28null and reduced regulatory T cells (Tregs). However, whether immune disturbances are due to ESRD or primary disease is not yet clear. As diabetes mellitus is the leading cause of ESRD, we evaluated its impact on the immune profile of ESRD patients. Methods: CD28null, Tregs, and natural killer cells were initially analyzed by flow cytometry in 30 predialysis ESRD patients due to diabetes (DM), 30 non-DM (NDM), and 25 healthy controls. Measurements were repeated after 6 months on hemodialysis (HD) or peritoneal dialysis (CAPD). Results: The percentage of CD4 + CD28null cells, CD8 + CD28null cells, and Tregs showed significant differences in DM, NDM, and controls; mean rank 33.71 vs. 25.68 vs. 18.88, p = 0.006, 37.79 vs. 28.82 vs. 17.08, p = 0.008, and 20.79 vs. 26.12 vs. 41.33, p = 0.001, respectively. DM vs. NDM had increased CD4 + CD28null and CD8 + CD28null cells, 11.5% (1.5%–24%) vs. 4.1% (0–42.3%), p = 0.02 and 61.3% (24%–76%) vs. 43% (5.7%–85%), p = 0.04, respectively. After 6 months on HD but not CAPD, DM showed a significant further increase in CD4 + CD28null cells, from 30 (14–100) to 52.7 (15–203), p = 0.02; and CD8 + CD28null cells, from 137 (56–275) to 266 (103–456), p = 0.01. Conclusions: Diabetes mellitus affects T-cell subtypes even at predialysis stage, though changes become more prominent after commencement on HD

    Impact of Τh1 and Τh2 cytokines in the progression of idiopathic nephrotic syndrome due to focal segmental glomerulosclerosis and minimal change disease

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    Background: Differential diagnosis between primary focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) is sometimes difficult as nephrotic syndrome is the main clinical symptom in both diseases. Objectives: This study has attempted to evaluate the urinary excretion of Th1 and Th2 cytokines as potential biomarkers in distinguishing the two types of nephrotic syndrome, and predicting outcome of renal function. Patients and Methods: Thirty-six patients with FSGS (M/F 22/14, Age; 41.9 ± 17 years, SCr=1.7 ± 0.8 mg/dL, UProt=4.7 ± 5.5 g/24 h), and 21 with MCD (M/F 5/16, Age; 41.4 ± 15 years, SCr = 1 ± 0.4 mg/dL, UProt = 7.9 ± 9.3 g/24 h) were included in the study. Τh1 (IL-2, IL-12, GM-CSF, INF-γ, TNF-α) and Th2 cytokines (IL-4, IL-5, IL-10, IL-13) were measured by multiple cytokine assay, Luminex technology, in first morning urinary samples collected at the day of renal biopsy. Results: No significant differences in urinary excretion of all cytokines were found between FSGS and MCD patients. In FSGS however, IL-12 urinary levels were independent factor correlated with both global sclerosis (R = 0.5, P = 0.009) and interstitial fibrosis (R = 0.5, P = 0.02). Th1 cytokines (IL-2 and GM-CSF) were significantly increased in FSGS patients who did not respond to treatment (P = 0.03 and P = 0.007, respectively). Th2 cytokines (IL-4, IL-5, IL-10, IL-13) were significantly increased in MCD patients with frequent relapses (P = 0.05, P = 0.001, P = 0.01, P = 0.03). Conclusions: Urinary excretion of Th1 and Th2 cytokines cannot discriminate FSGS from MCD. Th1 cytokines, especially IL-12, IL-2 and GM-CSF, may be involved in pathology and progression of FSGS, while Th2 cytokines are implicated in frequent relapses of nephrotic syndrome in MCD

    Circulating anti-phospholipase A2 receptor antibodies as a diagnostic and prognostic marker in Greek patients with idiopathic membranous nephropathy – a retrospective cohort study

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    Introduction. Circulating autoantibodies against phospholipase A2 receptor (anti-PLA2R) are recognized as key elements in the pathogenesis of idiopathic membranous nephropathy. In current clinical practice, they are increasingly gaining attention as novel tools for diagnosis and disease monitoring. We investigated the diagnostic and prognostic utility of anti-PLA2R antibody measurements in Greek patients with biopsy-proven membranous nephropathy

    Associations between Maternal and Offspring Hair Cortisol Concentrations and Child Behavioral Symptoms in Mother-Child Pairs with Perinatal Mental Disorders

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    Maternal perinatal mental disorders (PMD) are associated with developmental and behavioral problems in children, probably mediated by the programming of the hypothalamic–pituitary–adrenal (HPA) axis. Increased cortisol concentrations during the antenatal and perinatal periods have been related to long-term effects on children’s behavior and stress response. We aimed to investigate the association of hair cortisol concentrations (HCC) between mothers, with (n = 16) and without PMD (n = 30), and their children, aged between 18 and 48 months. Participants were evaluated with a clinical interview and questionnaires for the Depression Anxiety Stress Scale and the Child Behavior Checklist for ages 1½–5. Maternal and child HCCs were compared between the two groups. Children of the PMD group had increased symptoms of attention deficit hyperactivity disorder. A positive linear association between maternal and child HCC was observed only in the total sample of mother–child dyads and the control group. In the PMD group, children’s HCCs were significantly associated with child anxiety/depression symptoms. Aggressive behavior and oppositional/defiant problems correlated significantly with children’s own HCCs, and their mother’s too. These findings suggest that a chronic dysregulation of maternal and child HPA axis and their associations in the PMD dyads may underlie the linkage among prolonged maternal stress, child behavioral/emotional problems and stress responses

    Factors associated with poor adherence to vaccination against hepatitis viruses, streptococcus pneumoniae and seasonal influenza in HIV-infected adults

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    Introduction: Vaccination against various pathogens is recommended for HIV positive adults. There are not sufficient data either on vaccination coverage of HIV positive adults or the risk factors associated with poor adherence to routine vaccination. Patients-Methods: During the period 2004–2014 vaccination coverage of a group of HIV infected adults against hepatitis A virus (HAV), hepatitis B virus (HBV), seasonal influenza virus and pneumococcal disease was recorded. Vaccination coverage was separated into two chronological periods, before and after 2010, as 2010 marks the start of the economic crisis in Greece. Results: 1210 patients were included in our study. Vaccine coverage throughout the study for hepatitis B, hepatitis A, seasonal influenza and pneumococcal infection was 73.6%, 70.4%, 39% and 79%, respectively. The complete lack of insurance coverage was an independent factor of non-compliance in all proposed vaccines (vaccination against pneumococcal disease: OR: 0.82 95%CI: 0.49–1.35, vaccination against HBV: OR: 0.82, 95% CI: 0.45–1.49, vaccination against HAV OR: 0.54, 95%CI: 0.34–0.87, vaccination against influenza: OR: 1.27, 95% CI: 0.76–2.10). In addition, low educational level was associated with poor compliance to vaccination against pneumococcal disease, hepatitis A, hepatitis B, and influenza. Finally, the recommendation for vaccination after the onset of the economic crisis (2010) led to poor compliance to vaccination against HBV, HAV and pneumococcal disease, but not against influenza. Conclusions: In our study, vaccination coverage for vaccine-preventable diseases was found to be insufficient for HIV positive adults in Northern Greece. Also, low educational level, lack of insurance coverage and economic distress have contributed to poor vaccine compliance, leading to poor protection of the HIV positive population and decreased immune coverage in the community

    Prospective Analysis of B Lymphocyte Subtypes, before and after Initiation of Dialysis, in Patients with End-Stage Renal Disease

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    End-stage renal disease (ESRD) is followed by alterations in adaptive immunity. The aim of this study was to evaluate B lymphocyte subtypes in ESRD patients before and after hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD). Patients and Methods. CD5, CD27, BAFF, IgM and annexin were evaluated by flow cytometry on CD19+ cells in ESRD patients (n = 40), at time of initiating HD or CAPD (T0) and 6 months later (T6). Results. A significant reduction in ESRD-T0 compared to controls was noticed for CD19+, 70.8 (46.5) vs. 171 (249), p p p p = 0.002, CD19+BAFF+, 59.7 (37.8) vs. 127.9 (123.7), p p p = 0.03). CD19+CD5+ cells were the only cell type with an increased proportion in ESRD-T0 patients (2.7 (3.7) vs. 0.6 (1.1), p p = 0.02. Conclusions. B cells and most of their subtypes were significantly reduced in ESRD-T0 patients compared to controls, the only exception being CD19+CD5+ cells. Apoptotic changes were prominent in ESRD-T0 patients and were exacerbated by HD
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