1,049 research outputs found

    The two Ultraluminous X-ray sources in the galaxy NGC 925

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    NGC 925 ULX-1 and ULX-2 are two ultraluminous X-ray sources in the galaxy NGC 925, at a distance of 8.5 Mpc. For the first time, we analyzed high quality, simultaneous XMM-Newton and NuSTAR data of both sources. Although at a first glance ULX-1 resembles an intermediate mass black hole candidate (IMBH) because of its high X-ray luminosity ((2(2-4)×10404)\times10^{40} erg s1^{-1}) and its spectral/temporal features, a closer inspection shows that its properties are more similar to those of a typical super-Eddington accreting stellar black hole and we classify it as a `broadened disc' ultraluminous X-ray source. Based on the physical interpretation of this spectral state, we suggest that ULX-1 is seen at small inclination angles, possibly through the evacuated cone of a powerful wind originating in the accretion disc. The spectral classification of ULX-2 is less certain, but we disfavour an IMBH accreting at sub-Eddington rates as none of its spectral/temporal properties can be associated to either the soft or hard state of Galactic accreting black hole binaries.Comment: Accepted on MNRAS with very minor comments, 7 pages, 5 figures, 1 tabl

    Crizotinib-induced antitumour activity in human alveolar rhabdomyosarcoma cells is not solely dependent on ALK and MET inhibition

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    BACKGROUND: Rhabdomyosarcoma (RMS) is the most commonly diagnosed malignant soft tissue tumour in children and adolescents. Aberrant expression of Anaplastic Lymphoma Kinase (ALK) and MET gene has been implicated in the malignant progression of RMS, especially in the alveolar subtype. This observation suggests that crizotinib (PF-02341066), a kinase inhibitor against ALK and MET, may have a therapeutic role in RMS, although its antitumour activity in this malignancy has not yet been studied. METHODS: RH4 and RH30 alveolar RMS (ARMS) cell lines were treated with crizotinib and then assessed by using proliferation, viability, migration and colony formation assays. Multiple approaches, including flow cytometry, immunofluorescence, western blotting and siRNA-based knock-down, were used in order to investigate possible molecular mechanisms linked to crizotinib activity. RESULTS: In vitro treatment with crizotinib inhibited ALK and MET proteins, as well as Insulin-like Growth Factor 1 Receptor (IGF1R), with a concomitant robust dephosphorylation of AKT and ERK, two downstream kinases involved in RMS cell proliferation and survival. Exposure to crizotinib impaired cell growth, and accumulation at G2/M phase was attributed to an altered expression and activation of checkpoint regulators, such as Cyclin B1 and Cdc2. Crizotinib was able to induce apoptosis and autophagy in a dose-dependent manner, as shown by caspase-3 activation/PARP proteolytic cleavage down-regulation and by LC3 activation/p62 down-regulation, respectively. The accumulation of reactive oxygen species (ROS) seemed to contribute to crizotinib effects in RH4 and RH30 cells. Moreover, crizotinib-treated RH4 and RH30 cells exhibited a decreased migratory/invasive capacity and clonogenic potential. CONCLUSIONS: These results provide a further insight into the molecular mechanisms affected by crizotinib in ARMS cells inferring that it could be a useful therapeutic tool in ARMS cancer treatment

    Simplified reactor design for mixed culture-based electrofermentation toward butyric acid production

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    Mixed microbial culture (MMC) electrofermentation (EF) represents a promising tool to drive metabolic pathways toward the production of a specific compound. Here, the MMC-EF process has been exploited to obtain butyric acid in simplified membrane-less reactors operated by applying a difference of potential between two low-cost graphite electrodes. Ten values of voltage difference, from -0.60 V to -1.5 V, have been tested and compared with the experiment under open circuit potential (OCP). In all the tested conditions, an enhancement in the production rate of butyric acid (from a synthetic mixture of glucose, acetate, and ethanol) was observed, ranging from 1.3- to 2.7-fold relative to the OCP. Smaller enhancements in the production rate resulted in higher values of the calculated specific energy consumption. However, at all applied voltages, a low flow of current was detected in the one-chamber reactors, accounting for an average value of approximately -100 µA. These results hold a substantial potential with respect to the scalability of the electrofermentation technology, since they pinpoint the possibility to control MMC-based bioprocesses by simply inserting polarized electrodes into traditional fermenters

    Marteletes desgastados afetam negativamente as características operacionais da moagem e físicas do milho processado em moinho do tipo martelo

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    Foi conduzido um trabalho para avaliar os efeitos dos níveis de desgaste de marteletes de moinho tipo martelo, sobre características físicas do milho e operacionais de moagem. Foram utilizados quatro diferentes lotes de milho, um moinho martelo com motor de 3.500 RPM, cinco conjuntos de marteletes com diferentes níveis de desgaste do vértice (0, 20, 43, 57 e 63%) e quatro diferentes peneiras com diâmetros de furos de 1, 3, 5 e 12 mm sob um esquema fatorial 5x4, com quatro repetições em um total de 80 unidades experimentais. O aumento no diâmetro dos furos das peneiras influenciou (P<0,05) com aumento na produção, nos decibéis, no diâmetro geométrico médio (DGM), no desvio padrão geométrico (DPG), na densidade e com redução no consumo de energia elétrica e no ângulo de repouso (AR). O maior desgaste do martelo aumentou (P<0,05) o consumo de energia elétrica, DGM, DPG, AR e com redução (P<0,05) na produtividade e densidade. A análise de Linear response plateau (LRP) indicou piora na produtividade do equipamento a partir dos 55,1% de desgaste. Neste contexto, o desgaste dos marteletes influenciou negativamente as características operacionais do equipamento e físicas do milho. Para favorecer as características físicas do milho moído e evitar perdas na produtividade do equipamento recomenda-se a moagem com martelos isentos de desgaste

    Behavioral disorders in elementary school children and their relationship with family structure

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    The increase in behavioral disorders in children and adolescents is a factor of concern for health professionals. During the internship of nursing students in a public school, it was observed that 15 elementary students presented a medical diagnosis of mental disorder and/or were taking controlled medication. The present study aimed to characterize those students, and to identify the existence of risk factors for mental health problems, as well as their relationship with family structure and characteristics. The informers were 11 parents of students who agreed to participate in the study. Data were collected in June 2006, through a semi-structured interview that was conducted in the child's home. Results showed that the mental disorder is present in children/adolescents of both sexes and in different age groups. Most of the families were of a nuclear type and the average family income was of 3 to 5 minimum wages. The most frequent medical diagnosis was ADHD, 76% of the children presented family antecedents of mental disorder, 72% had difficulties at school, and a great number of them was exposed to humiliating situations. It was concluded that the characteristics of the studied families can be considered a risk factor for behavioral disorders, especially in relation to family antecedents and to inadequate educational practices. Further studies are needed on the theme in order to subsidize the elaboration of public policies of mental health.O aumento da incidência do distúrbios de conduta em crianças e adolescentes é um fator de preocupação para os profissionais de saúde. Durante as atividades de estágio de alunos de enfermagem em uma escola pública foi detectado que 15 alunos do ensino fundamental apresentavam diagnóstico médico de distúrbios de conduta e/ou tomava medicação controlada. O presente estudo teve como objetivo caracterizar estes alunos, identificar a existência de fatores de risco para problemas de saúde mental e sua relação com a estrutura e a característica familiar. Os participantes foram 11 pais de alunos que concordaram em participar do estudo. Os dados foram coletados por entrevista semi-estruturada realizada no domicílio da criança. Os resultados mostraram que o transtorno mental está presente em crianças / adolescentes de ambos os sexos e em diferentes faixas etárias. A maioria das famílias era do tipo nuclear e a renda familiar média era de 3 a 5 salários-mínimos. O diagnóstico médico mais freqüente era de transtorno de déficit de atenção/hiperatividade (TDAH); a maioria das crianças (76%) possuía antecedentes familiares de transtorno mental e apresentavam dificuldade escolar (72%); e boa parte das crianças era exposta a situações de humilhação. Conclui-se que as características das famílias estudadas podem ser consideradas um fator de risco para o distúrbio de conduta, especialmente em relação aos antecedentes familiares e a práticas educativas inapropriadas. Há necessidade de novos estudos sobre o tema que possam subsidiar a elaboração de políticas públicas de saúde mental

    Determination of the b quark mass at the M_Z scale with the DELPHI detector at LEP

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    An experimental study of the normalized three-jet rate of b quark events with respect to light quarks events (light= \ell \equiv u,d,s) has been performed using the CAMBRIDGE and DURHAM jet algorithms. The data used were collected by the DELPHI experiment at LEP on the Z peak from 1994 to 2000. The results are found to agree with theoretical predictions treating mass corrections at next-to-leading order. Measurements of the b quark mass have also been performed for both the b pole mass: M_b and the b running mass: m_b(M_Z). Data are found to be better described when using the running mass. The measurement yields: m_b(M_Z) = 2.85 +/- 0.18 (stat) +/- 0.13 (exp) +/- 0.19 (had) +/- 0.12 (theo) GeV/c^2 for the CAMBRIDGE algorithm. This result is the most precise measurement of the b mass derived from a high energy process. When compared to other b mass determinations by experiments at lower energy scales, this value agrees with the prediction of Quantum Chromodynamics for the energy evolution of the running mass. The mass measurement is equivalent to a test of the flavour independence of the strong coupling constant with an accuracy of 7 permil.Comment: 24 pages, 10 figures, Accepted by Eur. Phys. J.

    Study of Leading Hadrons in Gluon and Quark Fragmentation

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    The study of quark jets in e+e- reactions at LEP has demonstrated that the hadronisation process is reproduced well by the Lund string model. However, our understanding of gluon fragmentation is less complete. In this study enriched quark and gluon jet samples of different purities are selected in three-jet events from hadronic decays of the Z collected by the DELPHI experiment in the LEP runs during 1994 and 1995. The leading systems of the two kinds of jets are defined by requiring a rapidity gap and their sum of charges is studied. An excess of leading systems with total charge zero is found for gluon jets in all cases, when compared to Monte Carlo Simulations with JETSET (with and without Bose-Einstein correlations included) and ARIADNE. The corresponding leading systems of quark jets do not exhibit such an excess. The influence of the gap size and of the gluon purity on the effect is studied and a concentration of the excess of neutral leading systems at low invariant masses (<~ 2 GeV/c^2) is observed, indicating that gluon jets might have an additional hitherto undetected fragmentation mode via a two-gluon system. This could be an indication of a possible production of gluonic states as predicted by QCD.Comment: 19 pages, 6 figures, Accepted by Phys. Lett.

    Influence of gastrointestinal parasitism on biochemical variables in blood of laying hens

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    ABSTRACT Objective. This study describes the influence of endoparasites and diet on biochemical variables in sera of brown laying hens. Materials and methods. Biochemical parameters (seric levels of cholesterol, triglycerides, total protein, uric acid, albumin, and alanine aminotransferase activity) were assessed in blood samples of poultry. Three populations of laying hens of different properties (n=20 each) represented our experimental design, from which blood (serum) and feces were collected for biochemical and parasitological analyzes, respectively. Results. From 60 feces samples evaluated 49 were positive for the presence of parasites and 11 were negative. Among the positive samples, 23 had infection with Eimeria spp and the other 26 samples had mixed parasitism with Eimeria spp and Heterakis gallinarum, which influenced (increasing) the levels of total protein and globulin. However, when parasites were analyzed separately, it was observed that the infection by Eimeria spp affected parameters such as cholesterol (which increased, p=0.001) and triglycerides, showing lower results than when the hen was parasitized by Eimeria spp. (p=0.01). Significant (p<0.05) difference was observed in all biochemical variables when the three diets were compared. Conclusions. Our results allowed concluding that the parasitic infection and diet in laying hens influenced the results of serum biochemical parameters evaluated. The main conclusion we found that parasitism caused an increase in total protein and globulin (ie immune response), and there was a negative correlation between parasite load and albumin, uric acid and ALT

    Measurement and Interpretation of Fermion-Pair Production at LEP energies above the Z Resonance

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    This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e+e- -> ffbar process for centre-of-mass energies above the Z resonance, from sqrt(s) ~ 130 - 207 GeV at the LEP collider. The measurements are consistent with the predictions of the Standard Model and are used to study a variety of models including the S-Matrix ansatz for e+e- -> ffbar scattering and several models which include physics beyond the Standard Model: the exchange of Z' bosons, contact interactions between fermions, the exchange of gravitons in large extra dimensions and the exchange of sneutrino in R-parity violating supersymmetry.Comment: 79 pages, 16 figures, Accepted by Eur. Phys. J.
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