1,891 research outputs found

    Does pregnancy affect the metabolic equivalent at rest and during low intensity exercise?

    Get PDF
    Background: One metabolic equivalent (MET) is the amount of oxygen consumed while sitting at rest and is equal to 3.5 ml O2·kg-1·min-1. METs are often used to provide simple, practical, and easily understood values that reflect the energy cost of physical activity. It is plausible that the increase in body mass and absolute submaximal oxygen uptake during gestation has the potential to affect the MET of pregnant women. Objective: The aim of this study was to measure the MET during the second trimester of pregnancy and to compare this with non-pregnant women. In addition, the measured MET values were compared to those proposed by the Compendium of Physical Activities (CPA). Design: Ten pregnant and ten non-pregnant women participated in this study. Ventilatory variables and heart rate (HR) were measured during four conditions on two different days: Condition 1 - sitting, Condition 2 - lying, Condition 3 - treadmill walking and Condition 4 - cycling. The women performed two conditions on each testing day; one resting condition followed by one exercising condition. The data were analysed using a two-way ANOVA with repeated measures. Bonferroni’s tests were used when significant differences were detected. Results: The MET was not significantly different between pregnant and non-pregnant women either at rest or during exercise (p > 0.05). While cycling, the MET obtained by indirect calorimetry (IC) was significantly higher than the CPA predicted MET, regardless of group (pregnant cycling p = 0.002 and non-pregnant cycling p 0.05). In general, (combined pregnant and non-pregnant data), VE and HR were significantly higher during seated rest, when compared with supine rest and all ventilatory variables, HR and ratings of perceived exertion (RPE) were significantly higher during cycling, when compared with walking (p > 0.05). Conclusion: METs were unaffected by pregnancy at rest or when undertaking either walking or cycling exercise during the second trimester of pregnancy. The MET of cycling was significantly underestimated by the CPA, when compared to IC, in both groups

    Sign-reversal of the in-plane resistivity anisotropy in hole-doped iron pnictides

    Full text link
    The in-plane anisotropy of the electrical resistivity across the coupled orthorhombic and magnetic transitions of the iron pnictides has been extensively studied in the parent and electron-doped compounds. All these studies universally show that the resistivity ρa\rho_{a} across the long orthorhombic axis aOa_{O} - along which the spins couple antiferromagnetically below the magnetic transition temperature - is smaller than the resistivity ρb\rho_{b} of the short orthorhombic axis bOb_{O}, i. e. ρa<ρb\rho_{a}<\rho_{b}. Here we report that in the hole-doped compounds Ba1x_{1-x}Kx_{x}Fe2_{2}As2_{2}, as the doping level increases, the resistivity anisotropy initially becomes vanishingly small, and eventually changes sign for sufficiently large doping, i. e. ρb<ρa\rho_{b}<\rho_{a}. This observation is in agreement with a recent theoretical prediction that considers the anisotropic scattering of electrons by spin-fluctuations in the orthorhombic/nematic state.Comment: This paper has been replaced by the new version offering new explanation of the experimental results first reported her

    Studies of Copaifera luetzelburgii Harms in reproductive pharmacology: In vivo and in vitro approaches

    Get PDF
    The objective of this study was to evaluate the estrogenic and anti-estrogenic actions, as well as the reproductive and foetal toxicity, of the ethanol extract from Copaifera luetzelburgii (EEtOH-Cl). In the experiment of (anti) estrogenicity, nulliparous Wistar rats were treated for 3 days with EEtOH-Cl (125, 250 and 500 mg/kg); estradiol (E, 5 μg/kg); E + EEtOH-Cl; tamoxifen (T, 4mg/kg). This extract presented estrogenic activity by increasing the relative weight (%) of the uterus of rats treated at doses of 125, 250 and 500 mg/kg (0.267 ± 0.016*, 0.231 ± 0.014*, 0.242 ± 0.015*), and it showed anti-estrogenic activity when associated with estradiol (0.116 ± 0.006*, 0.103 ± 0.06*, 0.098 ± 0.05*), respectively. For assessment of toxicity in pregnancy, the animals were divided into two groups and treated daily with EEtOH-Cl. In the first group, the effect of the extract on the development of pregnancy from first to seventh day was observed, and in the second group, from 8 to 21 days, there was no change of these parameters or the viability of the progeny when the study assessed reproductive and foetal toxicity; however, there was shortening of pregnancy (125 mg/kg) without affecting the progeny. In the in vitro study, uterine strips of pregnant (P) and non-pregnant (NP) females were used. In both groups, half received EEtOH-Cl (vo) for 13 days (treated females - T), and the other half received EEtOH-Cl directly to the isolated organ bath system (untreated - NT). In vitro study on the uterus of pregnant animals pretreated with doses of 250 and 500 mg/kg showed that there was inhibition of KCl 80-induced phasic contractions (0.490 ± 0.110, 0.540 ± 0.092), respectively. Also, the contractions induced by oxytocin were inhibited at a dose of 500 mg/kg (0.380 ± 0.109). In non-pregnant, non-treated females, the extract at a concentration of 125 μg/mL (0.180 ± 0.062) also inhibited the contractions induced by oxytocin. Thus, EEtOH-Cl demonstrated estrogenic activity, but when combined with estradiol, it demonstrated anti-estrogenic activity. It did not induce toxicity in the progenitors or in the progeny, and it inhibited isometric contractions induced by oxytocin and KCl 80 mM in pregnant and non-pregnant rats.Keywords: Copaifera luetzelburgii, (anti-)estrogenicity, reproductive toxicity, phasic contractionsAfrican Journal of Biotechnology Vol. 12(24), pp. 3864-387

    Conductivity of electronic liquid-crystalline mesophases

    Get PDF
    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We investigate the connection between the transport properties and the thermodynamics of electronic systems with a tendency to form broken-symmetry mesophases evocative of the physics of liquid crystals. Through a hydrodynamic approach to the electronic transport in inhomogeneous systems, we develop a perturbative expansion for the macroscopic conductivity to study the transport of two-dimensional smectic and nematic phases. At the fluctuation-induced first-order phase transition expected for the smectic to isotropic transition, a jump in the macroscopic conductivity is predicted, with a directional dependence that reflects the fluctuation spectrum of the order parameter. When elastic fluctuation modes melt the smectic phase into a nematic phase, the resultant nematic order parameter is shown to be linearly proportional to the conductivity anisotropy. We also outline qualitative comparisons with recent experimental works on strongly correlated materials that show evidences of electronic liquid-crystalline mesophases.7818Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Ames Laboratory operated for the U.S. Department of Energy by Iowa State University [DE-AC02-07CH11358]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Ames Laboratory operated for the U.S. Department of Energy by Iowa State University [DE-AC02-07CH11358

    Validation of a fluorescence in situ hybridization method using peptide nucleic acid probes for detection of helicobacter pylori clarithromycin resistance in gastric biopsy specimens

    Get PDF
    Here, we evaluated a previously established peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) method as a new diagnostic test for Helicobacter pylori clarithromycin resistance detection in paraffin-embedded gastric biopsy specimens. Both a retrospective study and a prospective cohort study were conducted to evaluate the specificity and sensitivity of a PNA-FISH method to determine H. pylori clarithromycin resistance. In the retrospective study (n 30 patients), full agreement between PNA-FISH and PCR-sequencing was observed. Compared to the reference method (culture followed by Etest), the specificity and sensitivity of PNA-FISH were 90.9% (95% confidence interval [CI], 57.1% to 99.5%) and 84.2% (95% CI, 59.5% to 95.8%), respectively. In the prospective cohort (n 93 patients), 21 cases were positive by culture. For the patients harboring clarithromycin- resistant H. pylori, the method showed sensitivity of 80.0% (95% CI, 29.9% to 98.9%) and specificity of 93.8% (95% CI, 67.7% to 99.7%). These values likely represent underestimations, as some of the discrepant results corresponded to patients infected by more than one strain. PNA-FISH appears to be a simple, quick, and accurate method for detecting H. pylori clarithromycin resistance in paraffin-embedded biopsy specimens. It is also the only one of the methods assessed here that allows direct and specific visualization of this microorganism within the biopsy specimens, a characteristic that allowed the observation that cells of different H. pylori strains can subsist in very close proximity in the stomach

    Rupture of a Congenital Aneurysm of the Non-Coronary Sinus of Valsalva Into the Right Atrium

    Get PDF
    Apresenta-se o caso de um doente avaliado por sopro cardíaco contínuo, em que o estudo ecocardiográfico permitiu diagnosticar ruptura de aneurisma congénito do seio de Valsalva (SV) para a aurícula direita. Os autores fazem uma breve revisão sobre os aspectos clínicos desta patologia

    The Percentage of [−2]Pro–Prostate-Specific Antigen and the Prostate Health Index Outperform Prostate-Specific Antigen and the Percentage of Free Prostate-Specific Antigen in the Detection of Clinically Significant Prostate Cancer and Can Be Used as Reflex Tests

    Get PDF
    Context.—: There is a need to avoid the overdiagnosis of prostate cancer (PCa) and to find more specific biomarkers. Objective.—: To evaluate the clinical utility of [-2]pro-prostate-specific antigen ([-2]proPSA) derivatives in detecting clinically significant PCa (csPCa) and to compare it with prostate-specific antigen (PSA) and with the percentage of free PSA (%fPSA). Design.—: Two hundred thirty-seven men (PSA: 2-10 ng/mL) scheduled for a prostate biopsy were enrolled. Parametric and nonparametric tests, receiver operating characteristic curves, and logistic regression analysis were applied. Outcomes were csPCa and overall PCa. Results.—: Both [-2]proPSA derivatives were significantly higher in csPCa and overall PCa (P < .001). The areas under the curves for the prediction of csPCa were higher for the percentage of [-2]proPSA (%[-2]proPSA) (0.781) and the prostate health index (PHI) (0.814) than for PSA (0.651) and %fPSA (0.724). There was a gain of 11% in diagnostic accuracy when %[-2]proPSA or PHI were added to a base model with PSA and %fPSA. Twenty-five percent to 29% of biopsies could have been spared with %[-2]proPSA (cutoff: ≥1.25%) and PHI (cutoff: ≥27), missing 10% of csPCas. The same results could have been achieved by using [-2]proPSA as a reflex test, when %fPSA was 25% or less (cutoffs: ≥1.12% and ≥24 for %[-2]proPSA and PHI, respectively). Conclusions.—: The [-2]proPSA derivatives improve the diagnostic accuracy of csPCa when the PSA value is between 2 and 10 ng/mL, sparing unnecessary biopsies and selecting patients for active surveillance. [-2]proPSA can be used as a reflex test when %fPSA is 25% or less, without reducing the diagnostic accuracy for csPCa and the number of spared biopsies.info:eu-repo/semantics/publishedVersio

    Visualizing the microscopic coexistence of spin density wave and superconductivity in underdoped NaFe1-xCoxAs

    Full text link
    Although the origin of high temperature superconductivity in the iron pnictides is still under debate, it is widely believed that magnetic interactions or fluctuations play an important role in triggering Cooper pairing. Because of the relevance of magnetism to pairing, the question of whether long range spin magnetic order can coexist with superconductivity microscopically has attracted strong interests. The available experimental methods used to answer this question are either bulk probes or local ones without control of probing position, thus the answers range from mutual exclusion to homogeneous coexistence. To definitively answer this question, here we use scanning tunneling microscopy to investigate the local electronic structure of an underdoped NaFe1-xCoxAs near the spin density wave (SDW) and superconducting (SC) phase boundary. Spatially resolved spectroscopy directly reveal both the SDW and SC gap features at the same atomic location, providing compelling evidence for the microscopic coexistence of the two phases. The strengths of the SDW and SC features are shown to anti correlate with each other, indicating the competition of the two orders. The microscopic coexistence clearly indicates that Cooper pairing occurs when portions of the Fermi surface (FS) are already gapped by the SDW order. The regime TC < T < TSDW thus show a strong resemblance to the pseudogap phase of the cuprates where growing experimental evidences suggest a FS reconstruction due to certain density wave order. In this phase of the pnictides, the residual FS has a favorable topology for magnetically mediated pairing when the ordering moment of the SDW is small.Comment: 18 pages, 4 figure
    corecore