811 research outputs found

    The Initial-Value Problem of Spherically Symmetric Wyman Sector Nonsymmetric Gravitational Theory

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    We cast the four-dimensional field equations of the Nonsymmetric Gravitational Theory (NGT) into a form appropriate for numerical study. In doing so, we have restricted ourselves to spherically symmetric spacetimes, and we have kept only the Wyman sector of the theory. We investigate the well-posedness of the initial-value problem of NGT for a particular data set consisting of a pulse in the antisymmetric field on an asymptotically flat space background. We include some analytic results on the solvability of the initial-value problem which allow us to place limits on the regions of the parameter space where the initial-value problem is solvable. These results are confirmed by numerically solving the constraints.Comment: REVTeX 3.0 with epsf macros and AMS symbols, 18 pages, 9 figure

    Abelian Anomalies in Nonlocal Regularization

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    Nonlocal regularization of QED is shown to possess an axial anomaly of the same form as other regularization schemes. The Noether current is explicitly constructed and the symmetries are shown to be violated, whereas the identities constructed when one properly considers the contribution from the path integral measure are respected. We also discuss the barrier to quantizing the fully gauged chiral invariant theory, and consequences.Comment: 21 pages, UTPT-93-0

    Re(I) tricarbonyl complex of 1,10-phenanthroline-5,6-dione: DNA binding, cytotoxicity, antiinflammatory and anti-coagulant effects towards platelet activating factor

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    The complex fac-[Re(CO)3(phendione)Cl] (1) (where phendione = 1,10-phenanthroline-5,6-dione) has been synthesized and fully characterized by UV–visible, FTIR, and NMR techniques. The DNA binding properties of 1 are investigated by UV-spectrophotometric (melting curves), covalent binding assay, CV (cyclic voltammetry), circular dichroism (CD) and viscosity measurements. Experimental data indicate that 1 fits into the major groove without disrupting the helical structure of the B-DNA in contrast to the free phendione which intercalates within the base pairs of DNA. Upon irradiation, complex 1promotes the cleavage of plasmid pBR322 DNA from supercoiled form I to nicked form II via a proton coupled electron transfer mechanism. This comes as a result of experimental data in anaerobic/aerobic conditions and in the presence of DMSO. The biological activities of 1 and its precursors [Re(CO)5Cl] and phendione are tested towards a series of cancerous cell lines as glioblastoma (T98G), prostate cancer (PC3) and breast cancer (MCF-7) as well as platelet activating factor (PAF)-aggregation. Moreover, all the aforementioned compounds are tested for their ability to modulate PAF-basic metabolic enzyme activities in preparations of rabbit leukolytes. The in vitro experiments indicate that phendione has a better antitumor effect than cisplatin whereas [Re(CO)5Cl] is a better PAF inhibitor than both the phendione ligand and 1. Moreover, for the first time it is indicated that [Re(CO)5Cl], with a IC50 of 17 nM is comparable to the widely used PAF receptor antagonists, BN52021 and WEB2170 with IC50 of 30 and 20 nM, respectively, whereas 1 affects PAF-catabolism

    Deregulation of methylation of transcribed-ultra conserved regions in colorectal cancer and their value for detection of adenomas and adenocarcinomas

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    Expression of Transcribed Ultraconserved Regions (T-UCRs) is often deregulated in cancer. The present study assesses the expression and methylation of three T-UCRs (Uc160, Uc283 and Uc346) in colorectal cancer (CRC) and explores the potential of T-UCR methylation in circulating DNA for the detection of adenomas and adenocarcinomas. Expression levels of Uc160, Uc283 and Uc346 were lower in neoplastic tissues from 64 CRC patients (statistically significant for Uc160, p<0.001), compared to non-malignant tissues, while methylation levels displayed the inverse pattern (p<0.001, p=0.001 and p=0.004 respectively). In colon cancer cell lines, overexpression of Uc160 and Uc346 led to increased proliferation and migration rates. Methylation levels of Uc160 in plasma of 50 CRC, 59 adenoma patients, 40 healthy subjects and 12 patients with colon inflammation or diverticulosis predicted the presence of CRC with 35% sensitivity and 89% specificity (p=0.016), while methylation levels of the combination of all three T-UCRs resulted in 45% sensitivity and 74.3% specificity (p=0.013). In conclusion, studied T-UCRs’ expression and methylation status are deregulated in CRC while Uc160 and Uc346 appear to have a complicated role in CRC progression. Moreover their methylation status appears a promising non-invasive screening test for CRC, provided that the sensitivity of the assay is improved

    The Dynamical Instability of Static, Spherically Symmetric Solutions in Nonsymmetric Gravitational Theories

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    We consider the dynamical stability of a class of static, spherically-symmetric solutions of the nonsymmetric gravitational theory. We numerically reproduce the Wyman solution and generate new solutions for the case where the theory has a nontrivial fundamental length scale \mu^{-1}. By considering spherically symmetric perturbations of these solutions we show that the Wyman solutions are generically unstable.Comment: 13 pages, uses amslatex, graphicx and subfigure package

    Large-scale associations between the leukocyte transcriptome and BOLD responses to speech differ in autism early language outcome subtypes.

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    Heterogeneity in early language development in autism spectrum disorder (ASD) is clinically important and may reflect neurobiologically distinct subtypes. Here, we identified a large-scale association between multiple coordinated blood leukocyte gene coexpression modules and the multivariate functional neuroimaging (fMRI) response to speech. Gene coexpression modules associated with the multivariate fMRI response to speech were different for all pairwise comparisons between typically developing toddlers and toddlers with ASD and poor versus good early language outcome. Associated coexpression modules were enriched in genes that are broadly expressed in the brain and many other tissues. These coexpression modules were also enriched in ASD-associated, prenatal, human-specific, and language-relevant genes. This work highlights distinctive neurobiology in ASD subtypes with different early language outcomes that is present well before such outcomes are known. Associations between neuroimaging measures and gene expression levels in blood leukocytes may offer a unique in vivo window into identifying brain-relevant molecular mechanisms in ASD

    The dawn of preventing respiratory syncytial virus lower respiratory tract infections in children

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    Respiratory syncytial virus (RSV) is the commonest cause of lower respiratory tract infection (LRTI) in children, particularly those aged &lt;1 year. In South Africa (SA), increased hospitalisation rates during the RSV season, including access to intensive care facilities, place a huge burden on the healthcare system. Furthermore, RSV-LRTI during early childhood may lead to long-term respiratory sequelae, including recurrent wheezing, asthma, and impairment of lung function. Recently, two new RSV prevention strategies have emerged: nirsevimab, a long-acting monoclonal antibody, and a maternal RSV vaccine. Both strategies have shown high efficacy in reducing RSV-LRTI hospitalisation in infants and are being considered for licensure in SA. Implementation of these prevention strategies, combined with public engagement and collaboration between stakeholders, could significantly reduce RSV-related morbidity and mortality in SA

    A paediatric pain assessment and management survey at Rahima Moosa Mother and Child Hospital, Johannesburg, South Africa

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    Background. Painful experiences are common in the paediatric inpatient population. Immaturity and cognitive impairment may preclude clear description of such experiences, and requests for analgesia when needed. Methods of pain assessment and guidelines for treatment in the paediatric population are well established, but are not widely used. Limited data suggest that the situation is similar in South Africa (SA).Objectives. To review the assessment and management of pain in SA medical paediatric inpatients. The primary objective was to determine the proportion of children who receive analgesia where indicated. The secondary objectives were to determine the prevalence of pain, at presentation and among admitted patients, whether pain evaluations were performed and pain treated, and the adequacy of such treatment.Methods. A prospective cross-sectional survey of medical paediatric inpatients at Rahima Moosa Mother and Child Hospital (RMMCH) in Johannesburg, SA, was conducted. The tool used for data collection was specifically designed for the study, with sections for demographic data, patient or caregiver interview, and chart review. Pain assessments were done using the revised Face, Legs, Activity, Cry, Consolability Scale and the Neonatal/Infant Pain Scale. The analysis consisted of descriptive statistics of epidemiological data and comparative statistics using grouped variables, with the level of significance set at p&lt;0.05.Results. The sample consisted of 74 children, aged between 3 days and 4 years. Male patients accounted for 58% of the cohort. The prevalence of pain at admission was 73% (n=53). Eight percent (n=6) of the study sample had pain evaluation at admission, and only 1 child had been evaluated for pain within the preceding 24 hours. Of the 74 patients reviewed, 10% (n=7) received appropriate analgesia. Paracetamol was given to 31% of patients (n=23), either for pyrexia or for an undocumented indication. More than half of the study sample (59%; n=44) received no analgesia. The presence of pain, both by caregiver report (p=0.62) and by pain score (p=0.074), was not associated with the administration of analgesia.Conclusion. Pain in the paediatric population at RMMCH was found to be common, but it was seldom assessed, and validated pain scores were rarely used. The result was inadequate pain management in all the four domains of assessment, intervention, reassessment and ongoing management
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