Influence of pre-strain and bake hardening on the static and fatigue strength of a DP600 steel sheet

The influence of pre-strain on the tensile and fatigue properties of a dual phase DP600 steel was studied. The material was pre-strained by uni-axial tension in rolling and transverse direction. Thereafter, specimens were cut from the deformed plates in parallel or orthogonal to pre-strain direction. It was found that pre-strain increases yield and tensile strength. Results suggested that strain path change primarily affects the elastic-plastic transition during early stage of reloading. Pre-strained specimens showed an increase in high cycle regimes as a consequence of yield strength increment, irrespective of imposed pre-straining direction. A modified stress life equation that accounts for pre-strain was proposed and showed good agreement with experimental data. Bake hardening enhanced both tensile and high cycle fatigue resistance. Walker equation was successfully fitted to account for tensile mean stress. In low cycle fatigue, negligible influence of pre-strain was observed due to cyclic softening and residual stress relaxation

Experiences of community health nurse specialists in the tuberculosis burden setting

South Africa is one of the countries with the highest tuberculosis (TB) burden. The World Health Organization (WHO) statistics gave an estimated incidence of 322 000 cases of active TB in 2017. Furthermore, according to the WHO, an estimated 78 000 people in South Africa died from TB. The National Strategic Plan for HIV TB and STIs identified the Gauteng province in South Africa as one of the districts with a high TB burden; a decision informed by annual measurements of TB incidence, prevalence and mortality. The main objective of the study was to explore and describe the experiences of community health nurse specialists in the TB burden setting to ensure safe practices and excellent service delivery. A qualitative descriptive phenomenological design was used to describe the experiences of community health nurse specialists in the TB burden setting. A purposive sampling method was used to select 20 nurses. Ethical principles were adhered to and trustworthiness strategies were applied throughout the study. The data were collected through in-depth interviews and analysed using the 7 steps of Colaizzi’s method of data analysis. The findings indicated that community health nurse specialists are afraid of being infected with TB, and that patients who default treatment are of concern. The services of prevention, treatment, care and support needed by these nurses should be prioritised by the relevant management to ensure that service delivery is not compromised.https://upjournals.co.za/index.php/AJNM/indexpm2020Nursing Scienc

The epidemiology of AIDS-associated non-Hodgkin's lymphoma in the World Health Organization European Region

This paper describes the epidemiology of AIDS-associated non-Hodgkin's lymphoma (NHL) in the World Health Organization (WHO) European Region. Data, collected by the WHO Collaborating Centre on AIDS in Paris, France, were derived from the national AIDS surveillance systems of 21 countries. Among 53,042 cases reported as of the end of June 1991, 1,617 (3.0%) had NHL as the presenting clinical manifestation of AIDS. The proportion of cases presenting with NHL ranged from 1.1% in children infected perinatally to 3.9% among haemophiliacs. In comparison with intravenous drug users (IVDUs) (2.6% of whom had NHL), a moderate excess was found among homosexual or bisexual men (odds ratio - OR -:1.2, 95% confidence interval - CI -:1.0-1.3). Over time, the proportion of NHL was constant, but whereas among homosexual or bisexual men the frequency of NHL as AIDS-indicator disease significantly increased (9.7% per year), among IVDUs a significant downward trend emerged (17.1% per year). In respect to age, two peaks of NHL were seen at the age groups 10-19 (3.8%) and 50-59 (4.3%). The proportion of AIDS-associated NHL significantly increased with increasing age among homosexual and bisexual men and heterosexuals whereas it decreased among IVDUs. All these differences, however, have to be interpreted cautiously on account of the limitations of the reporting systems

Pemetrexed plus carboplatin in elderly patients with malignant pleural mesothelioma: combined analysis of two phase II trials

The incidence of malignant pleural mesothelioma (MPM) in elderly patients is increasing. In this study, pooled data from two phase II trials of pemetrexed and carboplatin (PC) as first-line therapy were retrospectively analysed for comparisons between age groups. Patients received pemetrexed 500 mg m−2 and carboplatin AUC 5 mg ml−1 min−1 intravenously every 21 days with standard vitamin supplementation. Elderly patients were defined as those ⩾70 years old. A total of 178 patients with an ECOG performance status of ⩽2 were included. Median age was 65 years (range 38–79), with 48 patients ⩾70 years (27%). Grade 3–4 haematological toxicity was slightly worse in ⩾70 vs <70-year-old patients, with neutropenia observed in 25.0 vs 13.8% (P=0.11), anaemia in 20.8 vs 6.9% (P=0.01) and thrombocytopenia in 14.6 vs 8.5% (P=0.26). Non-haematological toxicity was mild and similar in the two groups. No significant difference was observed in terms of overall disease control (60.4 vs 66.9%, P=0.47), time to progression (7.2 vs 7.5 months, P=0.42) and survival (10.7 vs 13.9 months, P=0.12). Apart from slightly worse haematological toxicity, there was no significant difference in outcome or toxicity between age groups. The PC regimen is effective and well tolerated in selected elderly patients with MPM

Simple Parameters from Complete Blood Count Predict In-Hospital Mortality in COVID-19

The clinical course of Coronavirus Disease 2019 (COVID-19) is highly heterogenous, ranging from asymptomatic to fatal forms. The identification of clinical and laboratory predictors of poor prognosis may assist clinicians in monitoring strategies and therapeutic decisions

Listeria pathogenesis and molecular virulence determinants

The gram-positive bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individuals. Clinical manifestations of invasive listeriosis are usually severe and include abortion, sepsis, and meningoencephalitis. Listeriosis can also manifest as a febrile gastroenteritis syndrome. In addition to humans, L. monocytogenes affects many vertebrate species, including birds. Listeria ivanovii, a second pathogenic species of the genus, is specific for ruminants. Our current view of the pathophysiology of listeriosis derives largely from studies with the mouse infection model. Pathogenic listeriae enter the host primarily through the intestine. The liver is thought to be their first target organ after intestinal translocation. In the liver, listeriae actively multiply until the infection is controlled by a cell-mediated immune response. This initial, subclinical step of listeriosis is thought to be common due to the frequent presence of pathogenic L. monocytogenes in food. In normal indivuals, the continual exposure to listerial antigens probably contributes to the maintenance of anti-Listeria memory T cells. However, in debilitated and immunocompromised patients, the unrestricted proliferation of listeriae in the liver may result in prolonged low-level bacteremia, leading to invasion of the preferred secondary target organs (the brain and the gravid uterus) and to overt clinical disease. L. monocytogenes and L. ivanovii are facultative intracellular parasites able to survive in macrophages and to invade a variety of normally nonphagocytic cells, such as epithelial cells, hepatocytes, and endothelial cells. In all these cell types, pathogenic listeriae go through an intracellular life cycle involving early escape from the phagocytic vacuole, rapid intracytoplasmic multiplication, bacterially induced actin-based motility, and direct spread to neighboring cells, in which they reinitiate the cycle. In this way, listeriae disseminate in host tissues sheltered from the humoral arm of the immune system. Over the last 15 years, a number of virulence factors involved in key steps of this intracellular life cycle have been identified. This review describes in detail the molecular determinants of Listeria virulence and their mechanism of action and summarizes the current knowledge on the pathophysiology of listeriosis and the cell biology and host cell responses to Listeria infection. This article provides an updated perspective of the development of our understanding of Listeria pathogenesis from the first molecular genetic analyses of virulence mechanisms reported in 1985 until the start of the genomic era of Listeria research

Robot Collision Avoidance based on Artificial Potential Field with Local Attractors

This paper presents a novel collision avoidance technique that allows the robot to reach a desired position by avoiding obstacles passing through preferred regions. The method combines the classical elements of the artificial potential fields in an original manner by handling local attractors and repulsors. The exact solution, which is given in a closed form, allows to sculpt a potential field so that local minima related to the local attractors are prevented and the global minimum is unperturbed. The results show the algorithm applied to mobile robot navigation and prove the capability of local attractors to influence the robot path