Exhaustive exercise in a hot environment can impair performance. Higher epinephrine plasma levels occur during exercise in heat, indicating greater sympathetic activity. This study examined the ...influence of exercise in the heat on stress levels. Nine young healthy men performed a maximal progressive test on a cycle ergometer at two different environmental conditions: hot (40°C) and normal (22°C), both between 40% and 50% relative humidity. Venous blood and saliva samples were collected pre-test and post-test. Before exercise there were no significant changes in salivary biomarkers (salivary IgA: p = 0.12; α-amylase: p = 0.66; cortisol: p = 0.95; nitric oxide: p = 0.13; total proteins: p = 0.07) or blood lactate (p = 0.14) between the two thermal environments. Following exercise, there were significant increases in all variables (salivary IgA 22°C: p = 0.04, 40°C: p = 0.0002; α-amylase 22°C: p = 0.0002, 40°C: p = 0.0002; cortisol 22°C: p = 0.02, 40°C: p = 0.0002; nitric oxide 22°C: p = 0.0005, 40°C: p = 0.0003, total proteins 22°C: p<0.0001, 40°C: p<0.0001 and; blood lactate 22°C: p<0.0001, 40°C: p<0.0001) both at 22°C and 40°C. There was no significant adjustment regarding IgA levels between the two thermal environments (p = 0.74), however the levels of α-amylase (p = 0.02), cortisol (p<0.0001), nitric oxide (p = 0.02) and total proteins (p = 0.01) in saliva were higher in the hotter conditions. Blood lactate was lower under the hot environment (p = 0.01). In conclusion, enduring hot temperature intensified stressful responses elicited by exercise. This study advocates that hot temperature deteriorates exercise performance under exhaustive stress and effort conditions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Chronic renal disease (CRD) affects a large portion of the population and is directly related to cardiovascular problems and hypertension, among others. Studies show that heart rate variability is ...directly affected by these problems. Physical-oriented exercises have been shown to be of fundamental importance in improving the adverse effects to dialysis treatment.
To analyze the effects of aerobic training during hemodialysis on autonomic heart rate modulation in patients with CRD.
Experimental study of an open, single group clinical trial. In this clinical trial, patients with CRD will initially undergo international physical activity questionnaire and kidney disease quality of life short form protocols, as well as monitoring of heart rate systolic, and diastolic blood pressure. After evaluation of the initial parameters, patients will undergo an aerobic exercise program for 12 weeks, in 3 weekly sessions, lasting 30 minutes a session. These evaluations will allow for a greater control of the disease, and monitoring of any improvements in the quality of life and self-esteem of these patients.
This study was approved following the guidelines and norms that regulate research involving human subjects, in Resolution No. 466/12 of the National Health Council. It was approved by the Research Ethics Committee of the Faculty of Juazeiro do Norte, with the number 1962 092. All patients who agree to participate in the research will sign the informed consent form. The results will be disseminated through peer-reviewed journal articles and conferences.
•The structural, dielectric properties of the addition in the Na2Nb4O11.•Complex impedance has been used to analyze the electrical and dielectric properties.•The modulus curves show a non-Debye ...behavior.
The effects of different additions of Bi2O3 (0, 2, 5 and 10wt.%) on Na2Nb4O11 ceramics have been studied by complex impedance spectroscopy analysis. The structural and dielectric properties of Na2Nb4O11ceramics with Bi2O3 additions are also discussed as a possible material for microwave and radio frequency applications. Solid state reaction method was used for producing the target compound. The present work also reports on sample preparation, where polyvinyl alcohol was used as a binder to reduce the brittleness and the organic binder was burnt out during sintering process. X-ray diffraction at room temperature was used to identify phases formed as well as optimum calcinations conditions the production of Na2Nb4O11 powder. Analysis was carried out to identify the pure-phase specimen by Rietveld refinement method. Based on this method a structure with the lattice parameters (a=10.840Å, b=6.162Å and c=12.745Å; α=90°, β=106.4° and γ=90°) was found. The dielectric and electrical properties of Na2Nb4O11 for appropriate amounts of Bi2O3 additions has showed a considerable enhancement and overriding applications for microwave and radio frequency communications. The electrical behavior (complex impedance Z*, complex modulus M*) were studied over a frequency range (1Hz to 1MHz) and temperature (553–713K).
In order to provide additional information on the behaviour of biochemical parameters related to stress responses to a specific long-term competition, we aimed to compare the stressful effects of a ...long-lasting competition on physiological variables in men and women.
This is a prospective observational analytical study. Twenty-five professional athletes, 15 men and 10 women, travelled 460 km for 4 days in an international edition of the Ecomotion/Pro AR World.
After the competition, we detected an increase in α-amylase and cortisol levels and a decrease in salivary immunoglobulin A (lgA) levels. The relative percentage changes in α-amylase, IgA and cortisol levels were significantly higher in women than in men, whereas women had lower relative percentage changes in glucose and lactate levels compared with men. There was a decrease in lymphocyte, eosinophil and monocyte counts, with relative percentage decreases in lymphocytes and monocytes being significantly higher in female athletes than in males. There were increases in the serum activities of total creatine kinase (CK), the creatine kinase myocardial isoform (CKMB), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) at the end of the test, with significantly higher elevations of total CK, CKMB and LDH in men and ALT in women.
Long-lasting competition induced stress, muscle damage, anaemia and changes in the immune system. Women had more intense responses of cortisol and leukocytes.
In this paper a study of TiO
2
addition (0, 2, 5 and 10 wt%) and its effects in the impedance spectra of Na
2
Nb
4
O
11
ceramic matrix was carried out. The structural, dielectric properties of the ...addition in the Na
2
Nb
4
O
11
matrix were discussed. In the preliminary structural studies, X-ray diffractograms of the samples were recorded at room temperature with X-ray diffractometer with Cu-kα. The Rietveld refinement method was used and confirmed the monoclinic structure for pure sample. A study based on complex impedance spectroscopy was carried and the dielectric properties were obtained over a frequency range (100 Hz–1 MHz) in room temperature (300 K). In the dielectric analysis at 1 MHz was observed relative permittivity of 99.46 for pure sample and 84.37 to sample added with 5 wt% of TiO
2
, those samples showed losses 3.55 × 10
−2
and 9.22 × 10
−2
, respectively. In relation to relaxation phenomenon, Cole–Cole function was used for fitting pure and added samples data.
Hyperprolactinemia might be related to weight gain, metabolic syndrome (MS), and insulin resistance (IR). Treatment with dopamine agonist (DA) has been shown to reduce body weight and improve ...metabolic parameters. The objectives of this study were to determine the prevalence of obesity, overweight, MS, and IR in patients with prolactinoma before and after therapy with DA and to evaluate the relation between prolactin (PRL), body weight, fat distribution, leptin levels, IR, and lipid profile before treatment. In addition, we investigated the correlation of the reduction in PRL levels with weight loss and metabolic profile improvement. Twenty‐two patients with prolactinoma completed 6 months of treatment with DA. These patients were submitted to clinical (BMI, waist circumference, blood pressure (BP)), laboratory evaluation (leptin, glucose, low‐density lipoprotein (LDL)‐cholesterol, and triglyceride (TG) levels) and abdominal computed tomography (CT) before and after treatment. The statistical analyses were done by nonparametric tests. At the beginning of the study, the prevalence of obesity, overweight, MS, and IR was 45, 27, 27, and 18%, respectively. After 6 months of treatment with DA, PRL levels normalized, but no significant difference in BMI was observed. However, there was a significant decrease on homeostasis model assessment of insulin resistance (HOMAIR) index, glucose, LDL‐cholesterol, and TG levels. This study suggests a possible involvement of prolactinoma on the prevalence of obesity. We should consider that DA may be effective on improving metabolic parameters, and we speculate that a period longer than 6 months of treatment is necessary to conclude whether this drug can interfere in the body weight of patients with prolactinoma.
Over the last two decades, there has been a considerably increase in the number of publications of research projects for the detection and classification of welding defects in radiographs using image ...processing and pattern recognition tools. All these research projects aim to set up an automatic or semi-automatic classification system for weld joint defects detected by the radiographic method. A classification system as such would allow a reduction in some inherent inexactnesses that occur in the conventional method, consequently increasing the precision of the report. This work is a study to estimate the accuracy of classification of the main classes of weld defects, such as: undercut, lack of penetration, porosity, slag inclusion, crack or lack of fusion. To carry out this work nonlinear pattern classifiers were developed, using neural networks. Also the largest number of radiographic patterns as possible was used as well as statistical inference techniques of random selection of data with (
Bootstrap) and without repositioning in order to estimate the accuracy of the classification. The results pointed to an estimated accuracy of around 80% for the classes of defects analyzed.
Granulocyte colony-stimulating factor (G-CSF) is increasingly being used to prevent febrile neutropenia associated with chemotherapy. Large-vessel vasculitis (LVV) has been recognized as a rare side ...effect of G-CSF treatment. We report a case of G-CSF associated LVV in a patient with breast cancer. While clear pathogenic mechanisms remain unknown, G-CSF may cause vasculitis due to inflammatory cytokines production. This adverse reaction should be recognized in patients with suggestive symptoms following the administration of pegfilgrastim. A 56-year-old woman with luminal B breast cancer who had undergone surgery and adjuvant chemotherapy, initially with paclitaxel, was started on a doxorubicin plus cyclophosphamide protocol, followed by supportive use of long-acting G-CSF pegfilgrastim. Following the administration of pegfilgrastim, the patient developed intermittent fever and was given empiric antibiotics in the outpatient setting with no improvement. There were no signs of cancer progression, and the contrast-enhanced CT scan highlighted wall thickening of the aortic arch and the proximal segment of the subclavian artery, which was not present in previous imaging studies. The patient was diagnosed with LVV, and a differential diagnosis was performed to rule out paraneoplastic setting, immune-mediated diseases, infection or other drug-induced vasculitis. Treatment with steroids was initiated and tapered with significant improvement and resolution of the radiological signs of aortitis.
Parabens, alkyl ester derivatives from p‐hydroxybenzoic acid, are extensively used as antimicrobial preservatives. Nonetheless, due to its widespread and massive employment, several studies ...highlighted the association between parabens and alterations in the reproductive system. This study aimed to relate the adverse effect of the most commonly used parabens in testis mitochondria with male fertility. From all the parabens used, propyl and butyl were the ones that most negatively decreased the respiratory control ratio. In the case of butyl, inhibitions of 20% and 60% were observed, respectively, at the lowest and highest concentration, when compared to the control group. The membrane potential was only significantly affected by propyl (14%) and butyl (31%), and at a concentration of 250 µM. Succinate dehydrogenase, cytochrome c oxidase, and ATPase activities showed a nonsignificant decrease. Cytochrome c reductase, on the other hand, showed statistically significant inhibitions for both propyl (56%) and butylparaben (55%). The susceptibility to the mitochondrial permeability transition pore (MPTP) opening was increased by all parabens, although this increase was markedly significant for propyl and butyl. These results show that the susceptibility of mitochondria to parabens is dependent on the alkyl chain length and parabens hydrophobicity, and the main mitochondrial target is Complex II–III and MPTP. Hence, this study demonstrates the contribution of parabens exposition to the inhibition of testis mitochondrial function and their putative noxious effect on the male reproductive system.
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