271 research outputs found

    Noncommutative Corrections to the Robertson-Walker metric

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    Upon applying Chamseddine's noncommutative deformation of gravity we obtain the leading order noncommutative corrections to the Robertson-Walker metric tensor. We get an isotropic inhomogeneous metric tensor for a certain choice of the noncommutativity parameters. Moreover, the singularity of the commutative metric at t=0t=0 is replaced by a more involved space-time structure in the noncommutative theory. In a toy model we construct a scenario where there is no singularity at t=0t=0 at leading order in the noncommutativity parameter. Although singularities may still be present for nonzero tt, they need not be the source of all time-like geodesics and the result resembles a bouncing cosmology.Comment: 13 page

    A Study of Risk Management Practice of Highway Projects in Nigeria

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    Construction Risk Management must be given adequate attention in order to ensure a successful project that meets the expectation of project goals and objectives thus risk management practice in Nigeria with respect to highway projects is explored in this study. Questionnaire survey was adopted for a population of 82 professionals (highway engineers, quantity surveyors and land surveyors) in clients, consultants and contracting organisations, using stratified random sampling techniques. The data collected were analysed by determination of the mean of the responses from the respondents and one way Analysis of Variance (ANOVA). Result of the analysis showed that; lack of accepted industry model for analysis of risk is rated as the most influencing factor in the implementation of risk management practice in Nigeria, followed by human/ organizational resistance. There is no significant difference at 5% level of significance between the responses of the clients, consultants and contractors on risk identification tools usage and risks response tools usage, risks analysis techniques usage of all the respondents except algorithms and Monte Carlo simulation. The result further showed that risk management practice is low in Nigeria, as all the respondents agreed that the use of rule of thumbs in managing construction risks associated with highways is prevalent as against modern techniques that are widely in use in developed countries. The study recommended adequate training for all stakeholders in highway construction sector to improve management of risks thus meeting project goals of time, approved budgets, and quality, imbibing the health and safety culture,  and in an environmentally acceptable manner. Keywords: Development, Highways, Risk management

    Exploring Factors Influencing Changes in Incidence and Severity of Multisystem Inflammatory Syndrome in Children

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    Multisystem inflammatory syndrome (MIS-C) is a rare condition associated with COVID-19 affecting children, characterized by severe and aberrant systemic inflammation leading to nonspecific symptoms, such as gastrointestinal, cardiac, respiratory, hematological, and neurological disorders. In the last year, we have experienced a progressive reduction in the incidence and severity of MIS-C, reflecting the worldwide trend. Thus, starting from the overall trend in the disease in different continents, we reviewed the literature, hypothesizing the potential influencing factors contributing to the reduction in cases and the severity of MIS-C, particularly the vaccination campaign, the spread of different SARS-CoV-2 variants (VOCs), and the changes in human immunological response. The decrease in the severity of MIS-C and its incidence seem to be related to a combination of different factors rather than a single cause. Maturation of an immunological memory to SARS-CoV-2 over time, the implication of mutations of key amino acids of S protein in VOCs, and the overall immune response elicited by vaccination over the loss of neutralization of vaccines to VOCs seem to play an important role in this change

    Ifosfamide given by continous-intravenous infusion in association with vinorelbine in patients with antracycline-resistany metastatic breast cancer:A phase I-Ii clinical trial

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    Circulating Endothelial Cells: A New Possible Marker of Endothelial Damage in Kawasaki Disease, Multisystem Inflammatory Syndrome in Children and Acute SARS-CoV-2 Infection

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    Background: Kawasaki Disease (KD) and Multisystem Inflammatory Syndrome in Children (MIS-C) are pediatric diseases characterized by systemic inflammation and vascular injury, potentially leading to coronary artery lesions (CALs). Data on vascular injury occurring during acute COVID-19 (AC19) in children are still lacking. The aim of our study was to investigate endothelial injury in KD-, MIS-C- and AC19-dosing circulating endothelial cells (CECs). Methods: We conducted a multicenter prospective study. CECs were enumerated by CellSearch technology through the immunomagnetic capture of CD146-positive cells from whole blood. Results: We enrolled 9 KD, 20 MIS-C and 10 AC19. During the acute stage, the AC19 and KD patients had higher CECs levels than the MIS-C patients. From the acute to subacute phase, a significant CEC increase was observed in the KD patients, while a mild decrease was detected in the MIS-C patients. Cellular clusters/syncytia were more common in the KD patients. No correlation between CECs and CALs were found in the MIS-C patients. The incidence of CALs in the KD group was too low to investigate this correlation. Conclusions: Our study suggests a possible role of CECs as biomarkers of systemic inflammation and endothelial dysfunction in KD and MIS-C and different mechanisms of vascular injury in these diseases. Further larger studies are needed

    Combination of fecal calprotectin and initial coronary dimensions to predict coronary artery lesions persistence in Kawasaki disease

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    Kawasaki Disease (KD) is systemic vasculitis involving medium-sized vessels in children. The aim of our study is to determine if fecal calprotectin (FC) could be useful in predicting the development or persistence of coronary artery lesions (CALs) in KD. We conducted a prospective monocentric study including all consecutive diagnoses of. Clinical, laboratory, echocardiographic data were recorded during the acute and subacute phase, including FC. Correlations among laboratory values, FC, clinical manifestations, IVIG-responsiveness and CALs development were investigated. We enrolled 26 children (76.9% boys; median age 34.5 months). The combination of FC > 250 microg/g and z-score > 2 during the acute phase was associated with the persistence of CALs (p = 0.022). A z-score > 2 alone during the acute phase was not related to CALs during the subacute stage (p > 0.05). A neutrophil percentage > 70% and WBC > 15,000/mmc during the acute phase significantly correlated with the presence of CALs during the subacute phase (p = 0.008). C-reactive protein (CRP) > 13 mg/dL at KD onset was significantly associated with the presence of CALs during the acute (p = 0.017) and subacute phase (p = 0.001). The combination of FC > 250 microg/g and a z-score > 2 during the acute phase of KD may be used as a predictor of CALs persistence. It can be useful especially in children with an initial CRP < 13 mg/dl

    Human colonic in vitro fermentation of water-soluble arabinoxylans from hard and soft wheat alters Bifidobacterium abundance and short-chain fatty acids concentration

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    The human intestinal microbiome plays an important role in health due to the large number of beneficial effects related to the bacterial profile and the metabolites generated in the intestine. Arabinoxylans are compounds present in different cereals such as wheat and they can modulate the profile and functioning of some beneficial bacteria from human intestinal microbiota. In the present work, a colonic in vitro fermentation with human faecal inoculum was done using arabinoxylans extracted from Argentinian hard and soft wheat as substrates. Molecular size alteration of arabinoxylans were studied during fermentation and Lactobacillus and Bifidobacterium abundance as well as short chain fatty acids concentrations were determined. The arabinoxylans fermentation was proved to induce the growth of Bifidobacterium and the release of short-chain fatty acids. The speed and efficiency of fermentation were different for each of the arabinoxylan extracted from both wheat genotypes, perhaps because of differences in their chemical and physical structures. The consumption of water-extractable arabinoxylans (WE-AX) (either supplemented or enriched) to maintain the balance or modulate in a favorable way the profile of Bifidobacterium can be an important contribution to the human health.Fil: Paesani, Candela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Sciarini, Lorena Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Moiraghi, Malena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; Argentina. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Salvucci, Emiliano Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Prado, Samira B. R.. Universidade de Sao Paulo; BrasilFil: Perez, Gabriela Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; Argentina. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Fabi, João Paulo. Universidade de Sao Paulo; Brasi
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