45 research outputs found

    Oxygen-rich microporous carbons with exceptional hydrogen storage capacity

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    Porous carbons have been extensively investigated for hydrogen storage but, to date, appear to have an upper limit to their storage capacity. Here, in an effort to circumvent this upper limit, we explore the potential of oxygen-rich activated carbons. We describe cellulose acetatederived carbons that combine high surface area (3800 m2 g-1) and pore volume (1.8 cm3 g-1) that arise almost entirely (> 90%) from micropores, with an oxygen-rich nature. The carbons exhibit enhanced gravimetric hydrogen uptake (8.1 wt% total, and 7.0 wt% excess) at -196 ºC and 20 bar, rising to a total uptake of 8.9 wt% at 30 bar, and exceptional volumetric uptake of 44 g l-1 at 20 bar, and 48 g l-1 at 30 bar. At room temperature they store up to 0.8 wt% (excess) and 1.2 wt% (total) hydrogen at only 30 bar, and their isosteric heat of hydrogen adsorption is above 10 kJ mol-1

    Association Between Advanced Maternal Age and Maternal and Neonatal Morbidity: A Cross-Sectional Study on a Spanish Population

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    Background and objective: Over recent decades, a progressive increase in the maternal age at childbirth has been observed in developed countries, posing a health risk for both women and infants. The aim of this study was to analyze the association between advanced maternal age (AMA) and maternal and neonatal morbidity. Material and methods: A cross-sectional study of 3,315 births was conducted in the north of Spain in 2014. We compared childbirth between women aged 35 years or older, with a reference group of women aged between 24 and 27 years. AMA was categorized based on ordinal ranking into 35-38 years, 39-42 years, and >42 years to estimate a dose-response pattern (the older the age, the greater the risk). As an association measure, crude and adjusted Odds Ratios (OR) were estimated by non-conditional logistic regression and 95% Confidence Intervals (95%CI) were calculated. Results: Repeated abortions were more common among women of AMA in comparison to pregnant women aged 24-27 years (reference group): adjusted OR = 2.68; 95%CI (1.52-4.73). A higher prevalence of gestational diabetes was also observed among women of AMA, reaching statistical significance when restricted to first time mothers: adjusted OR = 8.55; 95%CI (1.12-65.43). In addition, the possibility of an instrumental delivery was multiplied by 1.6 and the possibility of a cesarean by 1.5 among women of AMA, with these results reaching statistical significance, and observing a dose-response pattern. Lastly, there were associations between preeclampsia, preterm birth (<37 weeks) and low birthweight, however without reaching statistical significance. Conclusion: Our results support the association between AMA and suffering repeated abortions. Likewise, being of AMA was associated with a greater risk of suffering from gestational diabetes, especially among primiparous women, as well as being associated with both instrumental deliveries and cesareans among both primiparous and multiparous women

    Electron tomography of DJANGOS.

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    <p><b>A.</b> Tomographic slice of an EM thick section showing a nuclear pore-associated structure formed in HeLa cells expressing B12-HA. Cytoplasm and nucleus are labeled with “C” and “N,” respectively. The thick arrow points to an atypical nuclear pore structure in cross-section at the junction with the nuclear envelope; the thin arrow points to a classic nuclear pore in the double membrane inside the nucleus. <b>B.</b> End-on view of the atypical nuclear pore at the neck of the double-membrane structure. <b>C.</b> 3D rendering of the tomogram shows the NPCs in blue. Also see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0094322#pone.0094322.s004" target="_blank">Movie S1</a>.</p

    O uso de enxerto homólogo na revisão de artroplastias do quadril com cimentação do componente acetabular Use of homologous graft in hip arthroplasty reviews with acetabular component cementation

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    A artroplastia total do quadril representa um grande avanço no tratamento das enfermidades ortopédicas que acometem o quadril. A soltura asséptica desta prótese pode causar lesões e perdas ósseas, representando um grande desafio para a reconstrução cirúrgica destas artroplastias. Uma das alternativas para a reconstrução é o uso do enxerto ósseo de banco de ossos, podendo este ser usado em bloco ou na forma picada. Este estudo, baseado em uma revisão da literatura sobre enxertos ósseos, teve como objetivo uma análise quanto à reconstrução com enxertos em bloco e picado e sua integração. O enxerto picado mostrou melhores resultados quanto à integração quando se consegue estabilidade da reconstrução. Quando não conseguimos uma boa estabilidade, o enxerto em bloco associado aos anéis de reforço sobressai como a melhor opção.<br>Hip total arthroplasty represents a breakthrough in the treatment of orthopaedic illnesses affecting the hip. The aseptic loosening of this prosthesis may cause injuries and bone losses, representing a great challenge for the surgical reconstruction of those arthroplasties. One alternative to reconstruction is the use of bone graft sourced by bone bases, which may be used as a block or in pieces. This study, based on a literature review addressing bone grafts, had as an objective to analyze reconstruction with grafts in blocks and in pieces and its union. The graft in pieces showed better results concerning union when reconstruction stability is achieved. When a good stability cannot be achieved, the graft in block combined with reinforcement rings is highlighted as the best option
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