Random distributions of initial porosity trigger regular necking patterns at high strain rates

At high strain rates, the fragmentation of expanding structures of ductile materials, in general, starts by the localization of plastic deformation in multiple necks. Two distinct mechanisms have been proposed to explain multiple necking and fragmentation process in ductile materials. One view is that the necking pattern is related to the distribution of material properties and defects. The second view is that it is due to the activation of specific instability modes of the structure. Following this, we investigate the emergence of necking patterns in porous ductile bars subjected to dynamic stretching at strain rates varying from 10[superscript 3] s[superscript −1] to 0.5×10[superscript 5]s[superscript −1] using finite-element calculations and linear stability analysis. In the calculations, the initial porosity (representative of the material defects) varies randomly along the bar. The computations revealed that, while the random distribution of initial porosity triggers the necking pattern, it barely affects the average neck spacing, especially, at higher strain rates. The average neck spacings obtained from the calculations are in close agreement with the predictions of the linear stability analysis. Our results also reveal that the necking pattern does not begin when the Considère condition is reached but is significantly delayed due to the stabilizing effect of inertia.K.E.N., S.O. and J.A.R.-M. acknowledge the support from the European Union’s Horizon2020 Programme (Excellent Science, Marie-Sklodowska-Curie Actions) under REA grant agreement no. 675602 (Project OUTCOME). J.A.R.-M. is also thankful to the Ministerio de Economía y Competitividad de España (Project no. EUIN2015-62556) for the financial support that partly supported this work

Short-term bone biochemical response to a single bout of high-impact exercise

Bone response to a single bout of exercise can be observed with biochemical markers of bone formation and resorption. The purpose of this study was to examine the response of bone biochemical markers to a single bout of exhaustive high-impact exercise. 15 physically active young subjects volunteered to participate. The subjects performed continuous bilateral jumping with the ankle plantarflexors at 65 % of maximal ground reaction force (GRF) until exhaustion. Loading was characterized by analyzing the GRF recorded for the duration of the exercise. Venous blood samples were taken at baseline, immediately after, 2h and on day 1 and day 2 after the exercise. Procollagen type I amino terminal propeptide (P1NP, marker of bone formation) and carboxyterminal crosslinked telopeptide (CTx, marker of bone resorption) were analyzed from the blood samples. CTx increased significantly (32 %, p = 0.015) two days after the exercise and there was a tendensy towards increase seen in P1NP (p = 0.053) one day after the exercise. A significant positive correlation (r = 0.49 to 0.69, p &le; 0.038) was observed between change in P1NP from baseline to day 1 and exercise variables (maximal slope of acceleration, body weight (BW) adjusted maximal GRF, BW adjusted GRF exercise intensity and osteogenic index). Based on the two biochemical bone turnover markers, it can be concluded that bone turnover is increased in response to a very<br /

Profil Des Infections Ostéoarticulaires En Consultation Rhumatologique Au CHU- Kara (Togo)

Introduction: Osteoarticular infections remain public health problems in Africa. We aim at determining the clinical forms, topographic and etiological osteoarticular infections in a rheumatology unit of northern Togo. Methods: We conducted a cross-sectional study from April 2012 to March 2015 on inpatient records having suffered from musculoskeletal infection. Results: Of the 1813 patients admitted to the department in three years, 86 (4.74%) suffered from musculoskeletal infection. Of them, 36 (41.86%) were men and 50 (58.1% 4) were women, with a sex ratio (M/F) of 0.72. The mean age of the patients was 45 years. The mean duration of disease progression was 3.5 months. The different clinical forms observed were: spondylitis (47 patients, 54.65%), infectious arthritis (31 cases, 36.05%) and osteomyelitis (eight cases; 9.30%). The infection was likely tuberculous in 53 patients (61.63%), including 44 cases of Pott's disease. A banal germ was mentioned in the 33 others patients (38.37%). In four cases, the germ was isolated: Staphylococcus aureus (three cases) and Staphylococcus epidermidis (one case). The joints most affected by the infection were the hip (nine patients) and the knee (eight patients). Infection was multifocal in 14 cases (16.27%). The main risk factors for the infection identified were: promiscuity and poor hygiene (59.30%), alcoholism (26.74%) and retroviral infection (12.79%). Conclusion: This study and joint infections are a common reason for rheumatology consultation in northern Togo with a significant share of multifocal forms

Early Impact of SARS-CoV-2 Pandemic on Immunization Services in Nigeria

Background: By 11 March 2022, there were 450,229,635 coronavirus disease (COVID-19) cases and 6,019,085 deaths globally, with Nigeria reporting 254,637 cases and 3142 deaths. One of the essential healthcare services that have been impacted by the pandemic is routine childhood immunization. According to the 2018 National Demographic and Health Survey, only 31% of children aged 12–23 months were fully vaccinated in Nigeria, and 19% of eligible children in the country had not received any vaccination. A further decline in coverage due to the pandemic can significantly increase the risk of vaccine-preventable-disease outbreaks among children in Nigeria. To mitigate such an occurrence, it is imperative to urgently identify how the pandemic and the response strategies have affected vaccination services, hence, the goal of the study. Methods: The research method was qualitative, including in-depth interviews of healthcare workers and focus group discussions (FGDs) with caregivers of children aged 0–23 months. We selected one state from each of the three zones of Nigeria: northern, central, and southern. Within each state, 10 local government areas and 20 healthcare facilities were purposively selected. In each facility, 10 healthcare workers were invited for interviews. Overall, 517 healthcare workers were interviewed. For the focus group discussion, 30 communities were selected. Within each selected community, six consenting caregivers were included. Overall, 180 caregivers participated. The data were analyzed using thematic inductive content analysis. Results: Three significant impacts that were observed are: difficulties in accessibility to immunization services, declining immunization demand and uptake among caregivers due to varying factors, and erosion of vaccine confidence among both caregivers and healthcare workers. Movement restriction and lockdown had numerous major impacts, such as decreased general healthcare service delivery, increased transportation costs, fewer engagements that promote vaccine uptake, and cessation of mobile vaccination campaigns that target hard-to-reach communities. Moreover, misinformation, conspiracy beliefs about the pandemic and COVID-19 vaccines, and risk perception negatively influenced general vaccine confidence. Conclusion: The results of this early impact study show that immunization was directly affected by the pandemic and provide insights into areas where interventions are needed for recovery

Effects of acute fatigue on the volitional and magnetically-evoked electromechanical delay of the knee flexors in males and females

Neuromuscular performance capabilities, including those measured by evoked responses, may be adversely affected by fatigue; however, the capability of the neuromuscular system to initiate muscle force rapidly under these circumstances is yet to be established. Sex-differences in the acute responses of neuromuscular performance to exercise stress may be linked to evidence that females are much more vulnerable to ACL injury than males. Optimal functioning of the knee flexors is paramount to the dynamic stabilisation of the knee joint, therefore the aim of this investigation was to examine the effects of acute maximal intensity fatiguing exercise on the voluntary and magnetically-evoked electromechanical delay in the knee flexors of males and females. Knee flexor volitional and magnetically-evoked neuromuscular performance was assessed in seven male and nine females prior to and immediately after: (i) an intervention condition comprising a fatigue trial of 30-seconds maximal static exercise of the knee flexors, (ii) a control condition consisting of no exercise. The results showed that the fatigue intervention was associated with a substantive reduction in volitional peak force (PFV) that was greater in males compared to females (15.0%, 10.2%, respectively, p < 0.01) and impairment to volitional electromechanical delay (EMDV) in females exclusively (19.3%, p < 0.05). Similar improvements in magnetically-evoked electromechanical delay in males and females following fatigue (21%, p < 0.001), however, may suggest a vital facilitatory mechanism to overcome the effects of impaired voluntary capabilities, and a faster neuromuscular response that can be deployed during critical times to protect the joint system

Prise En Charge Infirmière De La Douleur Chez L’adulte Au CHU-Kara (Togo)

Introduction: Pain is a frequent reason for consultation in health facilities. Thus, nurses are in the forefront in the fight against pain. The aim of this study was to determine the role of the nurse in the management of the painful adult patient. Methodology: It was a cross-sectional study conducted in 11 departments of Kara teaching hospital during two weeks. Nurses who had managed a painful adult in the past seven days were included in the study. Results: Thirty nurses participated in the study. They were made of 24 men (76.67%) and six women (23.33%). The average age of nurses was 35 years (extremes: 23 years old and 50 years old) and 43.33% of them had less than five years of work experience. The main etiologies of pain managed were: trauma (22%), headache (18%) and abdominal pain (14%). Pain assessment tools were almost non-existent. Fifty percent of nurses did not know pain assessment tools. The evaluation of pain was performed with conventional tools by 16% of nurses. The analogical visual scale was the most used (three out of five nurses). Nursing intervention was dominated by counseling (43%) and thermal stimulation (22%). The use of analgesics was carried out in 83.33% of cases. Conclusion: This study shows that few nurses evaluated the pain during its management in adults. Therefore, it is necessary to initiate medical training for Togolese nurses on the management of the painful patient in order to make them more effective

Individual response to different forms of resistance training in school-aged boys

The aim of this study was to examine individual responses to different forms of resistance training on measures of jumping and sprinting performance in school-aged boys. Eighty boys were categorized into two maturity groups (pre- or post-PHV) and randomly assigned to a plyometric training, resistance training, combined training, or control group. Intervention groups participated in training twice weekly for six weeks, with measures of acceleration, maximal running velocity, squat jump height and reactive strength index collected pre and post intervention. In the pre-PHV cohort, plyometric training and combined training resulted in significantly more positive responders than the other two groups in both sprint variables (standardized residual values > 1.96). In the post-PHV cohort, significantly more positive responders for acceleration and squat jump height resulted from traditional strength training and combined training groups, compared with other groups. Conversely, plyometric training and combined training resulted in a significantly greater number of positive responders than the other two groups for maximal velocity and reactive strength index. Control participants rarely demonstrated meaningful changes in performance over the six-week period. Irrespective of maturation, it would appear that combined training provides the greatest opportunity for most individuals to make short-term improvements in jump and sprint performance. Taking maturation into account, our data show that a plyometric training stimulus is important for individuals in the pre-PHV stage of development, whether as a standalone method or in combination with traditional strength training, when attempting to improve jumping and sprinting ability. However, individuals in the post-PHV stage require a more specific training stimulus depending on the performance variable that is being targeted for improvement

Numerical and functional defects of blood dendritic cells in early- and late-stage breast cancer

The generation of antitumour immunity depends on the nature of dendritic cell (DC)–tumour interactions. These have been studied mostly by using in vitro-derived DC which may not reflect the natural biology of DC in vivo. In breast cancer, only one report has compared blood DC at different stages and no longitudinal evaluation has been performed. Here we conducted three cross-sectional and one one-year longitudinal assessments of blood DC in patients with early (stage I/II, n=137) and advanced (stage IV, n=36) disease compared to healthy controls (n=66). Patients with advanced disease exhibit markedly reduced blood DC counts at diagnosis. Patients with early disease show minimally reduced counts at diagnosis but a prolonged period (1 year) of marked DC suppression after tumour resection. While differing in frequency, DC from both patients with early and advanced disease exhibit reduced expression of CD86 and HLA-DR and decreased immunostimulatory capacities. Finally, by comparing a range of clinically available maturation stimuli, we demonstrate that conditioning with soluble CD40L induces the highest level of maturation and improved T-cell priming. We conclude that although circulating DC are compromised by loco-regional and systemic breast cancer, they respond vigorously to ex vivo conditioning, thus enhancing their immunostimulatory capacity and potential for immunotherapy