EXTRAVERTED CHILDREN SWIM FASTER COMPARED TO INTROVERTED COUNTERPARTS REGARDLESS OF LIGHT AND SOUND NOISE LEVELS

Individual differences of personality are thought to influence motor performance. In terms of cortical arousal levels, because extraverts are infra-activated and introverts are hyper-activated, environment stimuli might enhance the impact of the extraversion trait on task performance. This study investigated the effect of light and sound noise on the swimming performance of extraverted and introverted children. 19 extraverts (12 boys, 7 girls) and 22 introverts (12 boys, 10 girls), ages 8.2 ± 0.9 years, adapted to water and swimming at intermediate levels. Participants performed two trials of the task (swimming 15 meters as fast as possible in crawl style) under two environment conditions: bright light/loud noise (A) and dim light/slight noise (B). Movements were filmed to allow calculation of time to complete the task and the stroke cycle. There was a significant effect for the group factor, with extraverts swimming faster than introverts. No effect was detected for the environment factor or the interaction group/environment. Regarding stroke cycle, no differences were found for group, environment or interaction. Although extraversion has not affected mechanical aspects of crawl style, compared to introverts, extraverts swan faster, showing a more effective process of reacting and executing movements in time-constraints tasks.Diferenças individuais de personalidade podem influenciar o desempenho motor. Em termos de ativação cortical, porque extrovertidos são infra-ativados e introvertidos hiperativados, os estímulos ambientais podem aumentar o efeito do traço de extroversão ao desempenhar tarefas. O presente estudo investigou o efeito da luminosidade e do ruído sonoro no desempenho natatório de crianças extrovertidas (19; 12 meninos, 7 meninas) e introvertidos (22; 12 meninos, 10 meninas), com idade de 8.2 ± 0.9 anos, adaptadas à água e com nível intermediário de natação. As crianças executaram duas tentativas da tarefa (nadar 15 metros o mais depressa possível em estilo crawl) sob duas condições ambientais: luz forte/ruído alto (A) e luz fraca/ruído baixo (B). Os movimentos foram filmados para cálculo de tempo para completar a tarefa e de ciclo de braçada. Houve efeito significativo para o fator grupo, com extrovertidos nadando mais rapidamente que introvertidos. Não houve efeito para o fator ambiente ou interação grupo/ambiente. Quanto ao ciclo de braçada, não houve diferenças para qualquer fator ou interação. Embora a extroversão não tenha afetado aspectos mecânicos do nado crawl, comparados aos introvertidos, os extrovertidos nadaram mais rapidamente, o que demonstra um processo mais efetivo para reagir e executar movimentos com restrições de tempo

Electrochemical noise and impedance of Au electrode/electrolyte interfaces enabling extracellular detection of glioma cell populations

Microelectrode arrays (MEA) record extracellular local field potentials of cells adhered to the electrodes. A disadvantage is the limited signal-to-noise ratio. The state-of-the-art background noise level is about 10 μVpp. Furthermore, in MEAs low frequency events are filtered out. Here, we quantitatively analyze Au electrode/electrolyte interfaces with impedance spectroscopy and noise measurements. The equivalent circuit is the charge transfer resistance in parallel with a constant phase element that describes the double layer capacitance, in series with a spreading resistance. This equivalent circuit leads to a Maxwell-Wagner relaxation frequency, the value of which is determined as a function of electrode area and molarity of an aqueous KCl electrolyte solution. The electrochemical voltage and current noise is measured as a function of electrode area and frequency and follow unambiguously from the measured impedance. By using large area electrodes the noise floor can be as low as 0.3 μVpp. The resulting high sensitivity is demonstrated by the extracellular detection of C6 glioma cell populations. Their minute electrical activity can be clearly detected at a frequency below about 10 Hz, which shows that the methodology can be used to monitor slow cooperative biological signals in cell populations.</p

On the true nature of renormalizability in Horava-Lifshitz gravity

We argue that the true nature of the renormalizability of Horava-Lifshitz gravity lies in the presence of higher order spatial derivatives and not in the anisotropic Lifshitz scaling of space and time. We discuss the possibility of constructing a higher order spatial derivatives model that has the same renormalization properties of Horava-Lifshitz gravity but that does not make use of the Lifshitz scaling. In addition, the state-of-the-art of the Lorentz symmetry restoration in Horava-Lifshitz-type theories of gravitation is reviewed.Comment: Latex file in Revtex style, 5 pages, no figures. v2: references added, version accepted for publication in Foundations of Physic

Venom alkaloids against Chagas disease parasite: search for effective therapies

Chagas disease is an important disease affecting millions of patients in the New World and is caused by a protozoan transmitted by haematophagous kissing bugs. It can be treated with drugs during the early acute phase; however, effective therapy against the chronic form of Chagas disease has yet to be discovered and developed. We herein tested the activity of solenopsin alkaloids extracted from two species of fire ants against the protozoan parasite Trypanosoma cruzi, the aetiologic agent of Chagas disease. Although IC50 determinations showed that solenopsins are more toxic to the parasite than benznidazole, the drug of choice for Chagas disease treatment, the ant alkaloids presented a lower selectivity index. As a result of exposure to the alkaloids, the parasites became swollen and rounded in shape, with hypertrophied contractile vacuoles and intense cytoplasmic vacuolization, possibly resulting in osmotic stress; no accumulation of multiple kinetoplasts and/or nuclei was detected. Overexpressing phosphatidylinositol 3-kinase—an enzyme essential for osmoregulation that is a known target of solenopsins in mammalian cells—did not prevent swelling and vacuolization, nor did it counteract the toxic effects of alkaloids on the parasites. Additional experimental results suggested that solenopsins induced a type of autophagic and programmed cell death in T. cruzi. Solenopsins also reduced the intracellular proliferation of T. cruzi amastigotes in infected macrophages in a concentration-dependent manner and demonstrated activity against Trypanosoma brucei rhodesiense bloodstream forms, which is another important aetiological kinetoplastid parasite. The results suggest the potential of solenopsins as novel natural drugs against neglected parasitic diseases caused by kinetoplastids.Fil: Silva, Rafael C. M. Costa. Universidade Federal do Rio de Janeiro; BrasilFil: Fox, Eduardo G. P.. Universidade Federal do Rio de Janeiro; Brasil. South China Agricultural University; ChinaFil: Gomes, Fabio M.. Universidade Federal do Rio de Janeiro; Brasil. National Institutes of Health; Estados UnidosFil: Feijó, Daniel F.. Universidade Federal do Rio de Janeiro; BrasilFil: Ramos, Isabela. Universidade Federal do Rio de Janeiro; BrasilFil: Koeller, Carolina M.. Universidade Federal do Rio de Janeiro; Brasil. University at Buffalo; Estados UnidosFil: Costa, Tatiana F. R.. Universidade Federal do Rio de Janeiro; BrasilFil: Rodrigues, Nathalia S.. Universidade Federal do Rio de Janeiro; BrasilFil: Lima, Ana P.. Universidade Federal do Rio de Janeiro; BrasilFil: Atella, Georgia C.. Universidade Federal do Rio de Janeiro; BrasilFil: Rocha de Miranda, Kildare. Universidade Federal do Rio de Janeiro; Brasil. Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem; BrasilFil: Schoijet, Alejandra Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Alonso, Guillermo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: de Alcântara Machado, Ednildo. Universidade Federal do Rio de Janeiro; BrasilFil: Heise, Norton. Universidade Federal do Rio de Janeiro; Brasi

An electrical method to measure low-frequency collective and synchronized cell activity using extracellular electrodes

An electrical method to measure extracellular bioelectrical activity in vitro is presented. This method exploits the Helmholtz capacitive double-layer established at the electrode surface. Small extracellular voltage variations in the order of μVs induce through the double-layer capacitor a displacement current that is measured. This current is then enhanced by a gain factor proportional to the electrode capacitance. In addition, when measurements are carried out at low frequencies in current mode the electrode contribution to the noise can be minimized. The performance of the electrodes and the method is demonstrated using zebrafish hearts and glioma cell cultures. We propose that this electrical method is an ideal tool to measure in vitro slow and temporally synchronized events that are often involved in long range intracellular signaling. Keywords: Extracellular electrodes, Bioelectrical signals, Displacement current, Electrical double-layer, Intercellular signalin

Quantum numbers of the X(3872)X(3872) state and orbital angular momentum in its ρ0Jψ\rho^0 J\psi decay

Angular correlations in $B^+\to X(3872) K^+$ decays, with $X(3872)\to \rho^0 J/\psi$, $\rho^0\to\pi^+\pi^-$ and $J/\psi \to\mu^+\mu^-$, are used to measure orbital angular momentum contributions and to determine the $J^{PC}$ value of the $X(3872)$ meson. The data correspond to an integrated luminosity of 3.0 fb$^{-1}$ of proton-proton collisions collected with the LHCb detector. This determination, for the first time performed without assuming a value for the orbital angular momentum, confirms the quantum numbers to be $J^{PC}=1^{++}$. The $X(3872)$ is found to decay predominantly through S wave and an upper limit of $4\%$ at $95\%$ C.L. is set on the fraction of D wave.Comment: 16 pages, 4 figure

Brain metabolism and cerebrospinal fluid biomarkers profile of non-amnestic mild cognitive impairment in comparison to amnestic mild cognitive impairment and normal older subjects

Abstract\ud \ud Introduction\ud Mild cognitive impairment (MCI) is classically considered a transitional stage between normal aging and dementia. Non-amnestic MCI (naMCI) patients, however, typically demonstrate cognitive deficits other than memory decline. Furthermore, as a group, naMCI have a lower rate of an eventual dementia diagnosis as compared to amnestic subtypes of MCI (aMCI). Unfortunately, studies investigating biomarker profiles of naMCI are scarce. The study objective was to investigate the regional brain glucose metabolism (rBGM) with [18F]FDG-PET and cerebrospinal fluid (CSF) biomarkers in subjects with naMCI as compared to a control group (CG) and aMCI subjects.\ud \ud \ud Methods\ud Ninety-five patients were included in three different groups: naMCI (N = 32), aMCI (N = 33) and CG (N = 30). Patients underwent brain MRI and [18F]FDG-PET. A subsample (naMCI = 26, aMCI = 28) also had an assessment of amyloid-β, tau, and phosphorylated tau levels in the CSF.\ud \ud \ud Results\ud Both MCI groups had lower rBGM in relation to the CG in the precuneus. Subjects with naMCI showed decreased right prefrontal metabolism as well as higher levels of CSF amyloid-β relative to aMCI subjects.\ud \ud \ud Conclusion\ud While amnestic MCI subjects showed a biomarker profile classically related to MCI due to Alzheimer’s disease, naMCI patients illustrated a decrease in both prefrontal hypometabolism and higher CSF amyloid-β levels relative to the aMCI group. These biomarker findings indicate that naMCI is probably a heterogeneous group with similar precuneus hypometabolism compared to aMCI, but additional frontal hypometabolism and less amyloid-β deposition in the brain. Clinical follow-up and reappraisal of biomarkers of the naMCI group is needed to determine the outcome and probable etiological diagnosis.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) numbers 2011/18245-4 and 2009/17398-1 in BrazilCoordination for the Improvement of Higher Education Personnel (CAPES)/Brazi

Brain metabolism and cerebrospinal fluid biomarkers profile of non-amnestic mild cognitive impairment in comparison to amnestic mild cognitive impairment and normal older subjects

Abstract\ud \ud Introduction\ud Mild cognitive impairment (MCI) is classically considered a transitional stage between normal aging and dementia. Non-amnestic MCI (naMCI) patients, however, typically demonstrate cognitive deficits other than memory decline. Furthermore, as a group, naMCI have a lower rate of an eventual dementia diagnosis as compared to amnestic subtypes of MCI (aMCI). Unfortunately, studies investigating biomarker profiles of naMCI are scarce. The study objective was to investigate the regional brain glucose metabolism (rBGM) with [18F]FDG-PET and cerebrospinal fluid (CSF) biomarkers in subjects with naMCI as compared to a control group (CG) and aMCI subjects.\ud \ud \ud Methods\ud Ninety-five patients were included in three different groups: naMCI (N = 32), aMCI (N = 33) and CG (N = 30). Patients underwent brain MRI and [18F]FDG-PET. A subsample (naMCI = 26, aMCI = 28) also had an assessment of amyloid-β, tau, and phosphorylated tau levels in the CSF.\ud \ud \ud Results\ud Both MCI groups had lower rBGM in relation to the CG in the precuneus. Subjects with naMCI showed decreased right prefrontal metabolism as well as higher levels of CSF amyloid-β relative to aMCI subjects.\ud \ud \ud Conclusion\ud While amnestic MCI subjects showed a biomarker profile classically related to MCI due to Alzheimer’s disease, naMCI patients illustrated a decrease in both prefrontal hypometabolism and higher CSF amyloid-β levels relative to the aMCI group. These biomarker findings indicate that naMCI is probably a heterogeneous group with similar precuneus hypometabolism compared to aMCI, but additional frontal hypometabolism and less amyloid-β deposition in the brain. Clinical follow-up and reappraisal of biomarkers of the naMCI group is needed to determine the outcome and probable etiological diagnosis.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) numbers 2011/18245-4 and 2009/17398-1 in BrazilCoordination for the Improvement of Higher Education Personnel (CAPES)/Brazi

Assessment of the genetic risks of a metallic alloy used in medical implants

The use of artificial implants provides a palliative or permanent solution for individuals who have lost some bodily function through disease, an accident or natural wear. This functional loss can be compensated for by the use of medical devices produced from special biomaterials. Titanium alloy (Ti-6Al-4V) is a well-established primary metallic biomaterial for orthopedic implants, but the toxicity of the chemical components of this alloy has become an issue of concern. In this work, we used the MTT assay and micronucleus assay to examine the cytotoxicity and genotoxicity, respectively, of an extract obtained from this alloy. The MTT assay indicated that the mitochondrial activity and cell viability of CHO-K1 cells were unaffected by exposure to the extract. However, the micronucleus assay revealed DNA damage and an increase in micronucleus frequency at all of the concentrations tested. These results show that ions released from Ti-6Al-4V alloy can cause DNA and nuclear damage and reinforce the importance of assessing the safety of metallic medical devices constructed from biomaterials