124 research outputs found

    Electron attachment to valence-excited CO

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    The possibility of electron attachment to the valence 3Π^{3}\Pi state of CO is examined using an {\it ab initio} bound-state multireference configuration interaction approach. The resulting resonance has 4Σ^{4}\Sigma^{-} symmetry; the higher vibrational levels of this resonance state coincide with, or are nearly coincident with, levels of the parent a3Πa^{3}\Pi state. Collisional relaxation to the lowest vibrational levels in hot plasma situations might yield the possibility of a long-lived CO^- state.Comment: Revtex file + postscript file for one figur

    Nesting properties and anisotropy of the Fermi surface of LuNi2_{2}B2_{2}C

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    The rare earth nickel borocarbides, with the generic formula RRNi2_{2}B2_{2}C, have recently been shown to display a rich variety of phenomena. Most striking has been the competition between, and even coexistence of, antiferromagnetism and superconductivity. We have measured the Fermi surface (FS) of LuNi2_{2}B2_{2}C, and shown that it possesses nesting features capable of explaining some of the phenomena experimentally observed. In particular, it had previously been conjectured that a particular sheet of FS is responsible for the modulated magnetic structures manifest in some of the series. We report the first direct experimental observation of this sheet.Comment: 4 pages, 4 PS figure

    Mechanistic studies of the modulation of cleavage activity of topoisomerase I by DNA adducts of mono- and bi-functional PtII complexes

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    Using electrophoresis and replication mapping, we show that the presence of DNA adducts of bifunctional antitumor cisplatin or monodentate [PtCl(dien)]Cl (dien = diethylenetriamine) in the substrate DNA inhibits eukaryotic topoisomerase 1 (top1) action, the adducts of cisplatin being more effective. The presence of camptothecin in the samples of platinated DNA markedly enhances effects of Pt–DNA adducts on top1 activity. Interestingly, the effects of Pt–DNA adducts on the catalytic activity of top1 in the presence of camptothecin differ depending on the sequence context. A multiple metallation of the short nucleotide sequences on the scissile strand, immediately downstream of the cleavage site impedes the cleavage by top1. On the other hand, DNA cleavage by top1 at some cleavage sites which were not platinated in their close proximity is notably enhanced as a consequence of global platination of DNA. We suggest that this enhancement of DNA cleavage by top1 may consist in its inability to bind to other cleavage sites platinated in their close neighborhood; thus, more molecules of top1 may become available for cleavage at the sites where top1 normally cleaves and where platination does not interfere

    Impact Factor: outdated artefact or stepping-stone to journal certification?

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    A review of Garfield's journal impact factor and its specific implementation as the Thomson Reuters Impact Factor reveals several weaknesses in this commonly-used indicator of journal standing. Key limitations include the mismatch between citing and cited documents, the deceptive display of three decimals that belies the real precision, and the absence of confidence intervals. These are minor issues that are easily amended and should be corrected, but more substantive improvements are needed. There are indications that the scientific community seeks and needs better certification of journal procedures to improve the quality of published science. Comprehensive certification of editorial and review procedures could help ensure adequate procedures to detect duplicate and fraudulent submissions.Comment: 25 pages, 12 figures, 6 table

    Caracterización Clínica e Histopatológica del Carcinoma Baso celular

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    Introduction: The basaloma also known as basal cell carcinoma is the most frequent case of skin cancer. It can be seen mostly in face, nose and forehead.Objective: To identify the clinical and histopathological characteristics of basal cell carcinoma in patients who underwent surgery at the Maxillo Facial Service of the Celia Sánchez Manduley University Hospital in Manzanillo, during the period from September to December 2016.Methodological Design: It was carried out a descriptive and observant study to identify the clinical and histopathological characteristics of the basal cell carcinoma in patients that were treated in the Maxillofacial Service of the Clinical-Surgical Hospital ´´ Celia Sánchez Manduley´´, between the months of September and December of 2016. The sample had 60 patients.Results: The basal cell carcinoma predominated in males (55%) mostly between the ages of 60 and 80 years (68,67%). This disease was most frequently presented in white people (75%); located mainly in the cheeks (43%), with a size between one and two centimeters. These lesions presented a low diagnosis error with only a two percentage.Conclusions: The research reveal a high frequency of this disease in elderly people mostly men, with a bigger tendency to be located in the facial regions sun exposed. It was also confirmed that these lesions were detected and treated in early stages. Their diagnosis and treatment are performed with a small margin of error.Introducción: el basaloma, también llamado carcinoma de células basales y carcinoma basocelular, es la forma más frecuente de cáncer de piel y se puede encontrar principalmente en cara, nariz y frente.Objetivo: identificar las características clínicas e histopatológicas del carcinoma basocelular en pacientes que fueron operados en el Servicio de Máxilo Facial del Hospital Universitario Celia Sánchez Manduley de Manzanillo, en el período comprendido entre los meses de septiembre a diciembre de 2016.Material y Métodos: se realizó un estudio observacional, descriptivo y de corte transversal para identificar las características clínicas e histopatológicas del carcinoma basocelular en pacientes que fueron operados en el Servicio de Máxilo Facial del Hospital Clínico-quirúrgico Celia Sánchez Manduley de Manzanillo, en el período comprendido entre los meses de septiembre a diciembre de 2016. La muestra estuvo constituida por 60 pacientes.Resultados:  el carcinoma basocelular predominó en el sexo masculino (55%) sobre todo en las edades de 60 a 80 años (68,67%). Esta lesión se presentó con mayor frecuencia en personas de piel blanca (75%); localizándose principalmente en las mejillas (43%) con un tamaño predominante de 1 a 2 cm. Esta lesión presentó bajo error diagnóstico con solo el 2%. Conclusiones: la investigación reveló una alta frecuencia de la enfermedad en personas de edad avanzada sobre todo en hombres, con mayor tendencia a presentarse en regiones faciales expuestas al sol. También se constató que las lesiones son detectadas y tratadas en un estado incipiente. Su diagnóstico y tratamiento se realzan con un margen de error muy pequeño

    Mouse Protocadherin-1 gene expression is regulated by cigarette smoke exposure in vivo

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    Protocadherin-1 (PCDH1) is a novel susceptibility gene for airway hyperresponsiveness, first identified in families exposed to cigarette smoke and is expressed in bronchial epithelial cells. Here, we asked how mouse Pcdh1 expression is regulated in lung structural cells in vivo under physiological conditions, and in both short-term cigarette smoke exposure models characterized by airway inflammation and hyperresponsiveness and chronic cigarette smoke exposure models. Pcdh1 gene-structure was investigated by Rapid Amplification of cDNA Ends. Pcdh1 mRNA and protein expression was investigated by qRT-PCR, western blotting using isoform-specific antibodies. We observed 87% conservation of the Pcdh1 nucleotide sequence, and 96% conservation of the Pcdh1 protein sequence between men and mice. We identified a novel Pcdh1 isoform encoding only the intracellular signalling motifs. Cigarette smoke exposure for 4 consecutive days markedly reduced Pcdh1 mRNA expression in lung tissue (3 to 4-fold), while neutrophilia and airway hyperresponsiveness was induced. Moreover, Pcdh1 mRNA expression in lung tissue was reduced already 6 hours after an acute cigarette-smoke exposure in mice. Chronic exposure to cigarette smoke induced loss of Pcdh1 protein in lung tissue after 2 months, while Pcdh1 protein levels were no longer reduced after 9 months of cigarette smoke exposure. We conclude that Pcdh1 is highly homologous to human PCDH1, encodes two transmembrane proteins and one intracellular protein, and is regulated by cigarette smoke exposure in vivo

    Novel approach to analysing large data sets of personal sun exposure measurements

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    Personal sun exposure measurements provide important information to guide the development of sun awareness and disease prevention campaigns. We assess the scaling properties of personal ultraviolet radiation (pUVR) sun exposure measurements using the wavelet transform (WT) spectral analysis to process long-range, high-frequency personal recordings collected by electronic UVR dosimeters designed to measure erythemal UVR exposure. We analysed the sun exposure recordings of school children, farmers, marathon runners and outdoor workers in South Africa, and construction workers and work site supervisors in New Zealand. We found scaling behaviour in all the analysed pUVR data sets. We found that the observed scaling changes from uncorrelated to long-range correlated with increasing duration of sun exposure. Peaks in the WT spectra that we found suggest the existence of characteristic times in sun exposure behaviour that were to some extent universal across our data set. Our study also showed that WT measures enable group classification, as well as distinction between individual UVR exposures, otherwise unattainable by conventional statistical methods
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