Mechanical characterization of the Amazonian Pomacea dolioides (Reeve, 1856) shell

We investigated the mechanical behavior of freshwater mollusk shells, Pomacea dolioides, collected from a floodplain area located in Amazonas, Brazil. With the purpose of characterizing the mechanical properties of the shells, bending, hardness and roughness tests were carried out. To determine the shell flexural strength, a new methodology was proposed for the calculation of it, considering the curved geometry of the specimens taken from the shells. It was also described the mechanical properties as a function of shell position and thickness, variation of the surface hardness along the shell and the low level of superficial irregularity in the inner layer of the shells. Shell presented a mean flexural rupture modulus (MOR) of 128.0 MPa, Rockwell HR15N hardness = 50 ± 8.3 and a low level of irregularities in the inner layer, roughness Ra = 0.160 μm.Investigamos el comportamiento mecánico de las conchas de moluscos de agua dulce, Pomacea dolioides, recolectados en un área de llanuras aluviales en Amazonas, Brasil. Con el fin de caracterizar las propiedades mecánicas de éstas, se utilizaron ensayos de flexión, dureza y rugosidad. Para determinar la resistencia a la flexión del material, se propuso una nueva metodología para el cálculo de la resistencia a la flexión, considerando la geometría curva de los cuerpos de prueba retirados de las conchas. También se describieron las propiedades mecánicas analizados en función de la posición y de la espesura de la concha, la variación de la superficie de la rigidez con el concha y el nivel bajo de irregularidad superficial en la superficie interna de las conchas. La concha presentó el Módulo de Ruptura a la Flexión (MOR) medio de 128.0 MPa, dureza superficial Rockwell HR15N = 50 ± 8.3 y un bajo nivel de irregularidades en la capa interna, con rugosidad Ra = 0.160 μm

Analyzing the Spectral Energy Cascade in Turbulent Channel Flow

An analysis of the spectral turbulent kinetic energy budget in a fully developed turbulent plane channel flow is performed. Direct numerical simulation data are evaluated at friction Reynolds numbers Reτ of 180 and 1000. The analysis is focused on the influence of the Reynolds number on the spectral cascade of energy and the corresponding energy cascade in physical space in the presence of inhomogeneity and anisotropy. The turbulent kinetic energy distribution is compared for both Reynolds numbers, and the relevant characteristics of the energy transfer process in a wall-bounded turbulent flow are described. Differences in energy cascade are noted between the Reynolds number at both low and high wavenumbers. The results of the analysis are further assessed with a comparison to an earlier study of spectral energy transfer at Reτ= 180

The Performance, Physiology and Morphology of Female and Male Olympic-Distance Triathletes

Sex differences in triathlon performance have been decreasing in recent decades and little information is available to explain it. Thirty-nine male and eighteen female amateur triathletes were evaluated for fat mass, lean mass, maximal oxygen uptake (VO2 max), ventilatory threshold (VT), respiratory compensation point (RCP), and performance in a national Olympic triathlon race. Female athletes presented higher fat mass (p = 0.02, d = 0.84, power = 0.78) and lower lean mass (p < 0.01, d = 3.11, power = 0.99). VO2 max (p < 0.01, d = 1.46, power = 0.99), maximal aerobic velocity (MAV) (p < 0.01, d = 2.05, power = 0.99), velocities in VT (p < 0.01, d = 1.26, power = 0.97), and RCP (p < 0.01, d = 1.53, power = 0.99) were significantly worse in the female group. VT (%VO2 max) (p = 0.012, d = 0.73, power = 0.58) and RCP (%VO2 max) (p = 0.005, d = 0.85, power = 0.89) were higher in the female group. Female athletes presented lower VO2 max value, lower lean mass, and higher fat mass. However, females presented higher values of aerobic endurance (%VO2 max), which can attenuate sex differences in triathlon performance. Coaches and athletes should consider that female athletes can maintain a higher percentage of MAV values than males during the running split to prescribe individual training. Keywords: VO2 max; female athlete; sports medicine; sports physiology; triathlo

Assessment of the risk of burnout and its associated factors in healthcare professionals during the COVID-19 pandemic: A prospective cohort study

IntroductionThe COVID-19 pandemic resulted in tremendous physical and psychological pressure on healthcare professionals, especially on those working in intensive care units (ICUs) and Emergency Departments (EDs). The present study intended to characterize the profile of these professionals which is associated with burnout and determine the potential predictors of such condition.MethodsA Prospective cohort study was carried out in a tertiary hospital between March 2020 and March 2021, in Salvador, Brazil. A standardized and validated version of the Oldenburg Burnout inventory (OLBI) was applied to assess risk of burnout together with data forms designed to collect information on sociodemographic characteristics and religious beliefs. ICU and ED healthcare professionals were evaluated during off-hours at two distinct periods of the COVID-19 pandemic, in 2020 and in 2021. Differences in the results obtained from each study participant between the timepoints were compared. A binary logistic regression analysis was performed to identify the predictors of burnout development independent of other confounding factors.ResultsSeventy-seven healthcare professionals with a median age of 33 (interquartile range [IQR]: 31–37.5) years and predominantly female (72.7%; n = 56) were enrolled. There were 62 professionals at risk of developing burnout through the OLBI. Those had a median age of 33 (IQR: 31–37) and female predominance (71%, n = 44). Disengagement and burnout were the only features which frequencies significantly changed over time, with increasing detection at the latest timepoint. Alcohol consumption was found to be an important risk factor for burnout development [adjusted odds ratio (aOR): 10.8 (95% CI: 1.8–64.2)]. Importantly, working in the ICU [aOR: 0.04 (95%CI: 0.01–0.32)] and the habit of praying daily [aOR: 0.07 (95%CI: 0.01–0.41)] were characteristics linked to reduced odds of burnout.DiscussionDisengagement substantially increased during the COVID-19 pandemic in healthcare professionals. Alcohol consumption favors the onset of burnout whereas habit of praying daily and working in the ICU are protective against such outcome. Institutional policies aimed at minimizing etilism may positively impact mental health of these professionals

Return to classes impact on mental health of university students during the COVID-19 pandemic

BACKGROUND The Coronavirus Disease 2019 (COVID-19) pandemic and the necessary social isolation and distancing measures - that were adopted to prevent spreading the virus, including the suspension of university classes - negatively impacted the mental health of young adults. The aim of the current study was to investigate whether returning to online classes, even not presential, during the social isolation of the COVID-19 pandemic, affected the mental health of university students. METHODS Forty students (10 men and 30 women) (age, 22.3±3.8 years; body mass, 62.5±17.8 kg; height, 165.6±8.7cm) from undergraduate health courses participated in the study. The students answered a self-administered questionnaire designed to gather personal and quarantine information as well as information about the frequency of depression (PHQ-9) and anxiety (GAD-7) symptoms. The questionnaire was answered before and after the return to online classes. RESULTS There was a significantly lower frequency of depression symptoms after the return to online classes (Z = -2.27; p = 0.02). However, there was no difference in anxiety symptoms before and after returning to online classes (Z = -0.51; p = 0.61). CONCLUSIONS Return to online classes positively impacted the mental health (decrease of frequency of depression symptoms) of university students. Future studies are needed to observe whether the changes observed after returning to school are maintained over time

Cayley: Aplicativo para o aprendizado de matrizes, determinantes e sistemas lineares

This paper presents the proposal for the development of the Cayley app,idealized as a complementary result of an extension project at a federal teachinginstitution in the city of Irati. The application is intended to help the student in thelearning of the matrices, determinants and linear systems, and it is being developed through the use of the App Inventor platform. In addition to contemplating a section with calculators referring to the theme, the application will have a section containing theoretical aspects regarding the theme

Renal tubular dysfunction in patients with American cutaneous leishmaniasis

Renal dysfunction seen in patients with American cutaneous leishmaniasis (ACL) has been attributed to the use of antimonials for treatment. To determine whether ACL itself causes tubular dysfunction, we measured renal function in 37 patients with ACL prior to their treatment and compared results to that in 10 healthy volunteers of similar mean age. None of the patients presented with glomerular dysfunction; however, 27 had a urinary concentrating defect. There was no statistical difference between groups in the pre- and post-desmopressin test of urine osmolality, but the post-test urine osmolality of the controls was significantly higher. Urinary AQP2 levels, determined by western blot of isolated exosomes, were found to be significantly lower in patients than in controls, whereas that of the cotransporter (NKCC2) was significantly higher. A urinary acidification defect (post-test pH greater than 5.50 following calcium chloride) was found in 15 patients. Pretest plasma bicarbonate was below normal in 12 patients as was the pretest plasma pH in 14. Expression of the Na/H exchanger (NHE3), H+-ATPase, and pendrin were all significantly higher in patients with ACL than in controls. A combined urinary concentration and acidification defect was found in 12 patients. Thus, the urinary concentrating defect of ACL may be caused by decreased AQP2, with increased NKCC2 compensatory. Pendrin upregulation may be related to the urinary acidification defect with increased NHE3 and H+-ATPase also compensatory. Hence, ACL can cause asymptomatic renal tubular dysfunction

Características clínicas e de neuroimagem molecular de pacientes brasileiros com doença de Parkinson e mutações nos genes PARK2 ou PARK8

OBJECTIVE: To describe clinical and neuroimaging (SPECT) characteristics of Brazilian patients with Parkinson's disease (PD) and mutations in PARK2 or PARK8 genes. METHOD: A total of 119 patients meeting clinical criteria for PD were evaluated. RESULTS: Of all patients studied, 13 had mutations in either PARK2 (n=9) or PARK8 genes (n=4). No statistically significant differences in clinical characteristics in both groups were seen. SPECT with [99mTc] TRODAT-1 showed significant differences between patient and control and the most remarkable difference was between PARK2 and control. CONCLUSION: The study found a frequency of mutation of 10.1% and it was most commonly seen in women. These patients had long disease course and high rates of dyskinesia after L-DOPA use. PARK8 patients did not have a relevant family history of PD.OBJETIVO: Descrever as características clínicas e de neuroimagem (SPECT) de pacientes brasileiros com doença de Parkinson e mutações PARK2 e PARK8. MÉTODO: Foram avaliados 119 pacientes com critérios clínicos para a doença de Parkinson. RESULTADO: Entre os pacientes avaliados foram encontrados 13 pacientes com mutação nos genes PARK2 (n=9) ou PARK8 (n=4). Não houve diferença significativa na avaliação das características clínicas entre os dois grupos. Os resultados de SPECT mostraram diferenças significativas quanto ao potencial de ligação do [99mTc] TRODAT-1 SPECT entre pacientes vs. controle, sendo a diferença mais pronunciada entre PARK2 e controle. CONCLUSÃO: A freqüência de mutação encontrada foi 10,1%, sendo mais comum em mulheres. Estes pacientes apresentavam longo tempo de doença e alta prevalência de discinesias associadas ao uso da levodopa. Nossos pacientes com PARK8 não apresentaram uma história familiar relevante de doença de Parkinson.Hospital Israelita Albert Einstein Instituto Israelita de Ensino e PesquisaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Division of Movement DisordersUNIFESP-EPM Laboratório Interdisciplinar de Neurociências ClínicasUNIFESP, EPM, Division of Movement DisordersUNIFESP, EPM Laboratório Interdisciplinar de Neurociências ClínicasSciEL

Amateur Female Athletes Perform the Running Split of a Triathlon Race at Higher Relative Intensity than the Male Athletes: A Cross-Sectional Study

Maximal oxygen uptake (V˙O2max), ventilatory threshold (VT) and respiratory compensation point (RCP) can be used to monitor the training intensity and the race strategy, and the elucidation of the specificities existing between the sexes can be interesting for coaches and athletes. The aim of the study was to compare ventilatory threshold (VT), respiratory compensation point (RCP), and the percentage of the maximal aerobic speed (MAS) that can be maintained in a triathlon race between sexes. Forty-one triathletes (22 men and 19 women), 42.1 ± 8.4 (26 to 60) years old, that raced the same Olympic triathlon underwent a cardiorespiratory maximal treadmill test to assess their VT, RPC, and MAS, and race speed. The maximal oxygen uptake (V˙O2max) (54.0 ± 5.1 vs. 49.8 ± 7.7 mL/kg/min, p < 0.001) and MAS (17 ± 2 vs. 15 ± 2 km/h, p = 0.001) were significantly higher in male than in female athletes. Conversely, there were no sex differences according to the percentage of V˙O2max reached at VT (74.4 ± 4.9 vs. 76.1 ± 5.4%, p = 0.298) and RCP (89.9 ± 3.6 vs. 90.6 ± 4.0%, p = 0.560). The mean speed during the race did not differ between sexes (12.1 ± 1.7 km/h and 11.7 ± 1.8 km/h, p = 0.506, respectively). Finally, men performed the running split at a lower percentage of speed at RCP than women (84.0 ± 8.7 vs. 91.2 ± 7.0%, respectively, p = 0.005). Therefore, male and female athletes accomplished the running split in an Olympic triathlon distance at distinct relative intensities, as female athletes run at a higher RCP percentage

Profile of Self-Care Capacity and Alcohol Use in Elderly Brazilians during the COVID-19 Outbreak: An Online Study

Background: Preventive and positive online coping strategies are essential for harm reduction associated with alcohol abuse among older adults in pandemic and social isolation scenarios. The objectives were to examine the relationship between alcohol use/abuse and physical capacity/self-care to perform the physical activities of daily living or impairment of the functional capacity of the elderly in the COVID-19 pandemic. Methods: An online cross-sectional survey was carried out. One hundred and one elderly people in the city of São Paulo, Brazil, participated in a community program. Results: Most participants (52.5%) showed excellent self-care skills. Approximately 12% of participants reported problems related to alcohol use/abuse. There was no association between self-care ability and abuse and probable alcohol dependence. Conclusions: Although most participants have excellent self-care and functional capacity and have not evidenced alcohol use/abuse, health professionals need to systematically provide information to prevent alcohol abuse, especially in scenarios of great emotional distress, such as in a pandemic. In addition, the online meetings held by the UAPI program were shown to be opportunities for social interaction and were essential to minimize the negative effects of the possible presence of alcohol use/abuse and the deteriorating performance of physical activities of daily living during a pandemic outbreak for the elderly