297 research outputs found

    Electrolytic preparation of high dielectric thin films

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    Electrolytic formation techniques for high dielectric materials in thin films - barium salts - titanate, zirconate, and niobat

    Electrolytic preparation of high dielectric films quarterly report, 3 aug. - 3 nov. 1964

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    Production of high dielectric films containing barium titanat

    Electrolytic preparation of high dielectric films quarterly report, may 4 - aug. 3, 1965

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    Electrolytic preparation of high dielectric thin film coatings on refractory metal substrate

    A putative antiviral role of plant cytidine deaminases

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    [EN] Background: A mechanism of innate antiviral immunity operating against viruses infecting mammalian cells has been described during the last decade. Host cytidine deaminases (e.g., APOBEC3 proteins) edit viral genomes, giving rise to hypermutated nonfunctional viruses; consequently, viral fitness is reduced through lethal mutagenesis. By contrast, sub-lethal hypermutagenesis may contribute to virus evolvability by increasing population diversity. To prevent genome editing, some viruses have evolved proteins that mediate APOBEC3 degradation. The model plant Arabidopsis thaliana genome encodes nine cytidine deaminases (AtCDAs), raising the question of whether deamination is an antiviral mechanism in plants as well. Methods: Here we tested the effects of expression of AtCDAs on the pararetrovirus Cauliflower mosaic virus (CaMV). Two different experiments were carried out. First, we transiently overexpressed each one of the nine A. thaliana AtCDA genes in Nicotiana bigelovii plants infected with CaMV, and characterized the resulting mutational spectra, comparing them with those generated under normal conditions. Secondly, we created A. thaliana transgenic plants expressing an artificial microRNA designed to knock-out the expression of up to six AtCDA genes. This and control plants were then infected with CaMV. Virus accumulation and mutational spectra where characterized in both types of plants. Results: We have shown that the A. thaliana AtCDA1 gene product exerts a mutagenic activity, significantly increasing the number of G to A mutations in vivo, with a concomitant reduction in the amount of CaMV genomes accumulated. Furthermore, the magnitude of this mutagenic effect on CaMV accumulation is positively correlated with the level of AtCDA1 mRNA expression in the plant. Conclusions: Our results suggest that deamination of viral genomes may also work as an antiviral mechanism in plants.This work was supported by the former Spanish Ministerio de Ciencia e InnovaciĂłn-FEDER grant BFU2009-06993 to SFE. JMC was supported by the CSIC JAE-doc program/Fondo Social Europeo. AG-P was supported by a grant for Scientific and Technical Activities and by grant P10-CVI-65651, both from Junta de AndalucĂ­a.MartĂ­n, S.; Cuevas, J.; Grande-Perez, A.; Elena Fito, SF. (2017). A putative antiviral role of plant cytidine deaminases. F1000Research. 1-14. https://doi.org/10.12688/f1000research.11111.2S11

    Effect of physical activity intervention based on a pedometer on physical activity level and anthropometric measures after childbirth: a randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Pregnancy and childbirth are associated with weight gain in women, and retention of weight gained during pregnancy can lead to obesity in later life. Diet and physical activity are factors that can influence the loss of retained pregnancy weight after birth. Exercise guidelines exist for pregnancy, but recommendations for exercise after childbirth are virtually nonexistent. The aim of this study was to evaluate the effect of physical activity intervention based on pedometer on physical activity level and anthropometric measures of women after childbirth.</p> <p>Methods</p> <p>We conducted a randomized controlled trial in which 66 women who had given birth 6 weeks to 6 months prior were randomly assigned to receive either a 12 week tailored program encouraging increased walking using a pedometer (intervention group, n = 32) or routine postpartum care (control group, n = 34). During the 12-week study period, each woman in the intervention group wore a pedometer and recorded her daily step count. The women were advised to increase their steps by 500 per week until they achieved the first target of 5000 steps per day and then continued to increase it to minimum of 10,000 steps per day by the end of 12<sup>th </sup>week. Assessed outcomes included anthropometric measures, physical activity level, and energy expenditure per week. Data were analyzed using the paired t-test, independent t-test, Mann-Whitney, chi-square, Wilcoxon, covariance analysis, and the general linear model repeated measures procedure as appropriate.</p> <p>Results</p> <p>After 12 weeks, women in the intervention group had significantly increased their physical activity and energy expenditure per week (4394 vs. 1651 calorie, <it>p </it>< 0.001). Significant differences between-group in weight (<it>P </it>= 0.001), Body Mass Index (<it>P </it>= 0.001), waist circumference (<it>P </it>= 0.001), hip circumference (<it>P </it>= 0.032) and waist-hip ratio (<it>P </it>= 0.02) were presented after the intervention. The intervention group significantly increased their mean daily step count over the study period (from 3249 before, to 9960 after the intervention, <it>p </it>< 0.001).</p> <p>Conclusion</p> <p>A physical activity intervention based on pedometer is an effective means to increase physical activity; reducing retention of weight gained during pregnancy and can improve anthropometric measures in postpartum women.</p> <p>Trial registration</p> <p>ISRCTN: <a href="http://www.controlled-trials.com/IRCT201105026362N1">IRCT201105026362N1</a></p

    Chimpanzee APOBEC3 proteins deter SIVs from any monkey business

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    Cross-species transmissions of viruses from animals to humans are at the origin of major human pathogenic viruses. While the role of ecological and epidemiological factors in the emergence of new pathogens is well documented, the importance of host factors is often unknown. Chimpanzees are the closest relatives of humans and the animal reservoir at the origin of the human AIDS pandemic. However, despite being regularly exposed to monkey lentiviruses through hunting, chimpanzees are naturally infected by only a single simian immunodeficiency virus, SIVcpz. Here, we asked why chimpanzees appear to be protected against the successful emergence of other SIVs. In particular, we investigated the role of the chimpanzee APOBEC3 genes in providing a barrier to infection by most monkey lentiviruses. We found that most SIV Vifs, including Vif from SIVwrc infecting western-red colobus, the chimpanzee's main monkey prey in West Africa, could not antagonize chimpanzee APOBEC3G. Moreover, chimpanzee APOBEC3D, as well as APOBEC3F and APOBEC3H, provided additional protection against SIV Vif antagonism. Consequently, lentiviral replication in primary chimpanzee CD4(+) T cells was dependent on the presence of a lentiviral vif gene that could antagonize chimpanzee APOBEC3s. Finally, by identifying and functionally characterizing several APOBEC3 gene polymorphisms in both common chimpanzees and bonobos, we found that these ape populations encode APOBEC3 proteins that are uniformly resistant to antagonism by monkey lentiviruses
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