370 research outputs found

    Rearranging the centromere of the human Y chromosome with φC31 integrase

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    We have investigated the ability of the integrase from the Streptomyces φC31 ‘phage to either delete or invert 1 Mb of DNA around the centromere of the human Y chromosome in chicken DT40 hybrid somatic cells. Reciprocal and conservative site-specific recombination was observed in 54% of cells expressing the integrase. The sites failed to recombine in the remaining cells because the sites had been damaged. The sequences of the damaged sites indicated that the damage arose as a result of repair of recombination intermediates by host cell pathways. The liability of recombination intermediates to damage is consistent with what is known about the mechanism of serine recombinase reactions. The structures of the products of the chromosome rearrangements were consistent with the published sequence of the Y chromosome indicating that the assembly of the highly repeated region between the sites is accurate to a resolution of about 50 kb. Mini-chromosomes lacking a centromere were not recovered which also suggested that neo-centromere formation occurs infrequently in vertebrate somatic cells. No ectopic recombination was observed between a φC31 integrase attB site and the chicken genome

    X-ray Linear Dichroism in cubic compounds: the case of Cr3+ in MgAl2O4

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    The angular dependence (x-ray linear dichroism) of the Cr K pre-edge in MgAl2O4:Cr3+ spinel is measured by means of x-ray absorption near edge structure spectroscopy (XANES) and compared to calculations based on density functional theory (DFT) and ligand field multiplet theory (LFM). We also present an efficient method, based on symmetry considerations, to compute the dichroism of the cubic crystal starting from the dichroism of a single substitutional site. DFT shows that the electric dipole transitions do not contribute to the features visible in the pre-edge and provides a clear vision of the assignment of the 1s-->3d transitions. However, DFT is unable to reproduce quantitatively the angular dependence of the pre-edge, which is, on the other side, well reproduced by LFM calculations. The most relevant factors determining the dichroism of Cr K pre-edge are identified as the site distortion and 3d-3d electronic repulsion. From this combined DFT, LFM approach is concluded that when the pre-edge features are more intense than 4 % of the edge jump, pure quadrupole transitions cannot explain alone the origin of the pre-edge. Finally, the shape of the dichroic signal is more sensitive than the isotropic spectrum to the trigonal distortion of the substitutional site. This suggests the possibility to obtain quantitative information on site distortion from the x-ray linear dichroism by performing angular dependent measurements on single crystals

    Possible Patient Early Diagnosis by Ultrasonic Noninvasive Estimation of Thermal Gradients into Tissues Based on Spectral Changes Modeling

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    To achieve a precise noninvasive temperature estimation, inside patient tissues, would open promising research fields, because its clinic results would provide early-diagnosis tools. In fact, detecting changes of thermal origin in ultrasonic echo spectra could be useful as an early complementary indicator of infections, inflammations, or cancer. But the effective clinic applications to diagnosis of thermometry ultrasonic techniques, proposed previously, require additional research. Before their implementations with ultrasonic probes and real-time electronic and processing systems, rigorous analyses must be still made over transient echotraces acquired from well-controlled biological and computational phantoms, to improve resolutions and evaluate clinic limitations. It must be based on computing improved signal-processing algorithms emulating tissues responses. Some related parameters in echo-traces reflected by semiregular scattering tissues must be carefully quantified to get a precise processing protocols definition. In this paper, approaches for non-invasive spectral ultrasonic detection are analyzed. Extensions of author's innovations for ultrasonic thermometry are shown and applied to computationally modeled echotraces from scattered biological phantoms, attaining high resolution (better than 0.1°C). Computer methods are provided for viability evaluation of thermal estimation from echoes with distinct noise levels, difficult to be interpreted, and its effectiveness is evaluated as possible diagnosis tool in scattered tissues like liver

    Site-specific recombination in Schizosaccharomyces pombe and systematic assembly of a 400kb transgene array in mammalian cells using the integrase of Streptomyces phage ϕBT1

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    We have established the integrase of the Streptomyces phage ϕBT1 as a tool for eukaryotic genome manipulation. We show that the ϕBT1 integrase promotes efficient reciprocal and conservative site-specific recombination in vertebrate cells and in Schizosaccharomyces pombe, thus establishing the utility of this protein for genome manipulation in a wide range of eukaryotes. We show that the ϕBT1 integrase can be used in conjunction with Cre recombinase to promote the iterative integration of transgenic DNA. We describe five cycles of iterative integration of a candidate mouse centromeric sequence 80 kb in length into a human mini-chromosome within a human-Chinese hamster hybrid cell line. These results establish the generality of the iterative site-specific integration technique

    Development of a device to study fatigue life of fixed partial dentures

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    [EN] Fixed partial dentures can be fabricated by means of different materials and with different manufacturing processes. In order to establish possible differences among them, their behaviour, as fatigue life or cement shear bond strength, have to be evaluated. This article presents a modular, economic and robust device to evaluate fixed partial dentures and dental crowns. A base to support the fixed partial dentures and a device to simulate masticatory loads have been developed. The device has got a simple design. It is based on a pneumatic piston, with a pressure regulator to control masticatory loads. On a first stage, only vertical forces have been taking into account. However, the device will allow simulating tangential masticatory loads on the other axis, studying the behaviour of the fixed partial dentures submerged in a solution similar to saliva, changing masticatory load application, etc. with little modifications.Gutiérrez Rubert, SC.; Meseguer Calas, MD.; Estal, R.; Folguera, F.; Vidal, V. (2012). Development of a device to study fatigue life of fixed partial dentures. AIP Conference Proceedings. 1431:877-884. doi:10.1063/1.4707646S877884143

    Carcinoma invasor, carcinoma in situ e hiperplasia epitelial ductal atípica: correlação dos achados histopatológicos entre mamotomia e cirurgia

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    OBJECTIVE: To compare the histopathological findings of carcinoma and atypical hyperplasia obtained with breast biopsy and the respective surgical procedures.MATERIAL AND METHODS: 527 breast biopsies were carried out at our services within an 18-month period. Out of these biopsies, 118 were diagnosed as carcinoma in situ or invasive carcinoma and atypical hyperplasia. Diagnosis was obtained with digital stereotactic breast biopsy. Patients presented asymptomatic, had subclinical lesions on mammographic screening, averaged 55 years of age, and were, in their majority, postmenopausal women.RESULTS: Out of the 118 patients who fulfilled our study criteria, we were able to establish a comparison with the histopathological findings of surgical biopsy in 73 cases (61,9%). There was a loss of follow up in 45 cases (38,1 %). The histopathological findings were compatible with those of breast biopsy in 60 cases (82%), both in relationto the type and histopathological grade of the lesion.CONCLUSIONS: Breast biopsy represents an important alternative to surgical biopsy for the diagnosis of nonpalpable breast lesions. It is a rapid, easy to operate methodthat provides optimal results. In addition, its results presented a good rate of agreement with the histopathological findings of surgical biopsy. The quality of the collected material was considered satisfactory for the purpose of diagnosis. OBJETIVO: Comparar os resultados histopatológicos de carcinoma e hiperplasia atípica obtidos através da mamotomia com os das respectivas biópsias cirúrgicas.MATERIAIS E MÉTODOS: Foram realizadas nesta instituição 527 mamotomias em 18 meses. Destas, 118 tiveram diagnóstico de carcinoma in situ ou invasor e hiperplasia atípica, através da mamotomia guiada por estereotaxia digital. As pacientes eram assintomáticas, apresentando lesão subclínica ao rastreio mamográfico. A idade média destas pacientes era de 55 anos e a maioria encontrava-se na pós-menopausa.RESULTADOS: Das 118 pacientes que preencheram os critérios para este estudo, foi possível realizar a comparação com os resultados histopatológicos da biópsia cirúrgica em 73 casos (61,9%). Em 45 casos houve perda de follow up (38,1%). O laudo histopatológico pós-cirúrgico foi compatível com o da mamotomia em 60 casos (82%), tanto em relação ao tipo quanto ao grau histopatológico da lesão.CONCLUSÃO: A mamotomia tem representado uma importante alternativa à biópsia cirúrgica para o diagnóstico das lesões impalpáveis da mama. Trata-se de um método rápido, de fácil realização, com ótimos resultados, além de apresentar boa taxa de concordância com os resultados histopatológicos obtidos através da biópsia cirúrgica. A qualidade do material obtido tem sido considerada satisfatória para o diagnóstico

    On the Harmony of Feminist Ethics and Business Ethics

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    If business requires ethical solutions that are viable in the liminal landscape between concepts and corporate office, then business ethics and corporate social responsibility should offer tools that can survive the trek, that flourish in this well-traveled, but often unarticulated, environment. Indeed, feminist ethics produces, accesses, and engages such tools. However, work in BE and CSR consistently conflates feminist ethics and feminine ethics and care ethics. I offer clarification and invoke the analytic power of three feminist ethicists 'in action' whose investigations into the "grey zones" of harms; identity and representational conventions; and "asymmetrical reciprocity" harmonize with business ethics' requirements

    Voice disorders and mental health in teachers: a cross-sectional nationwide study

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    International audienceBACKGROUND:Teachers, as professional voice users, are at particular risk of voice disorders. Among contributing factors, stress and psychological tension could play a role but epidemiological data on this problem are scarce. The aim of this study was to evaluate prevalence and cofactors of voice disorders among teachers in the French National Education system, with particular attention paid to the association between voice complaint and psychological status.METHODS:The source data come from an epidemiological postal survey on physical and mental health conducted in a sample of 20,099 adults (in activity or retired) selected at random from the health plan records of the national education system. Overall response rate was 53%. Of the 10,288 respondents, 3,940 were teachers in activity currently giving classes to students. In the sample of those with complete data (n = 3,646), variables associated with voice disorders were investigated using logistic regression models. Studied variables referred to demographic characteristics, socio-professional environment, psychological distress, mental health disorders (DSM-IV), and sick leave.RESULTS:One in two female teachers reported voice disorders (50.0%) compared to one in four males (26.0%). Those who reported voice disorders presented higher level of psychological distress. Sex- and age-adjusted odds ratios [95% confidence interval] were respectively 1.8 [1.5-2.2] for major depressive episode, 1.7 [1.3-2.2] for general anxiety disorder, and 1.6 [1.2-2.2] for phobia. A significant association between voice disorders and sick leave was also demonstrated (1.5 [1.3-1.7]).CONCLUSION:Voice disorders were frequent among French teachers. Associations with psychiatric disorders suggest that a situation may exist which is more complex than simple mechanical failure. Further longitudinal research is needed to clarify the comorbidity between voice and psychological disorders
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