284 research outputs found
Liquid lubrication in sheet metal forming at mesoscopic scale
The lubricant entrapment and escape phenomena in metal forming are studied experimentally as well as numerically. Experiments are carried out in strip reduction of aluminium sheet applying a transparent die to study the fluid flow between mesoscopic cavities. The numerical strategy is based on a weak fluid/structure coupling involving the Finite ElementMethod and analytical calculations. It allows to quantify the final shape of the lubricant pocket
Material behaviour at low temperatures for calibrating cryogenic machining numerical simulations
Abstract Recently, cryogenic machining of difficult-to-cut alloys has been adopted to increase tool life and improve the machined components surface integrity. Numerical models of cryogenic machining are being developed to evaluate the influence of the different process parameters. Up to now, their calibration in terms of material flow stress is fulfilled using data at conventional temperatures, whereas the material sensitivity to temperatures lower than the environment one should be taken into account. To this regard, the paper objective is to present material data, obtained through a newly developed Split Hopkinson Tension Bar, at cryogenic temperatures and high strain rates to properly calibrate cryogenic machining numerical models
Saquinavir Inhibits the malaria parasite's chloroquine resistance transporter
The antiretroviral protease inhibitors (APIs) ritonavir, saquinavir, and lopinavir, used to treat HIV infection, inhibit the growth of Plasmodium falciparum at clinically relevant concentrations. Moreover, it has been reported that these APIs potentiate the activity of chloroquine (CQ) against this parasite in vitro. The mechanism underlying this effect is not understood, but the degree of chemosensitization varies between the different APIs and, with the exception of ritonavir, appears to be dependent on the parasite exhibiting a CQ-resistant phenotype. Here we report a study of the role of the P. falciparum chloroquine resistance transporter (PfCRT) in the interaction between CQ and APIs, using transgenic parasites expressing different PfCRT alleles and using the Xenopus laevis oocyte system for the heterologous expression of PfCRT. Our data demonstrate that saquinavir behaves as a CQ resistance reverser and that this explains, at least in part, its ability to enhance the effects of CQ in CQ-resistant P. falciparum parasites. Copyrigh
Productive restructuring and the reallocation of work and employment: a survey of the “new” forms of social inequality
O propósito do presente artigo consiste
em questionar a inevitabilidade dos processos de
segmentação e precarização das relações de trabalho
e emprego, responsáveis pela inscrição de
“novas” formas de desigualdade social que alicerçam
o actual modelo de desenvolvimento das economias
e sociedades. Visa-se criticar os limites da
lógica econômica e financeira, de contornos globais,
que configuram um “novo espírito do capitalismo”,
ou seja, uma espécie de divinização da
ordem natural das coisas. Impõe-se fazer, por isso,
um périplo analítico pelas transformações em curso
no mercado de trabalho, acompanhado pela vigilância
epistemológica que permita enquadrar e
relativizar as (di)visões neoliberais e teses tecnodeterministas
dominantes. A perspectivação de cenários
sobre o futuro do trabalho encerrará este
périplo, permitindo-nos alertar para os condicionalismos
histórico-temporais, para a urgência de
se desocultar o que de ideológico e político existe
nas actuais lógicas de racionalização e para os
processos de ressimbolização do trabalho e emprego
enquanto “experiência social central” na
contemporaneidade.The scope of this paper is to question
the inevitability of the processes of segmentation
and increased precariousness of the relations
of labor and employment, which are responsible
for the introduction of “new” forms of
social inequality that underpin the current model
of development of economies and societies. It
seeks to criticize the limits of global financial and
economic logic, which constitute a “new spirit of
capitalism,” namely a kind of reverence for the
natural order of things. It is therefore necessary
to conduct an analytical survey of the ongoing
changes in the labor market, accompanied by epistemological
vigilance which makes it possible to
see neoliberal (di)visions and dominant technodeterministic
theses in context. The enunciation
of scenarios on the future of work will conclude
this survey and will make it possible to draw attention
to both the historical and temporal constraints
and to the urgent need to unveil what is
ideological and political in the prevailing logic of
rationalization and processes to reinstate work
and employment as a “central social experience”
in contemporary times
Clinical features and risk factors for severe and critical pregnant women with 2009 pandemic H1N1 influenza infection in China
<p>Abstract</p> <p>Background</p> <p>2009 pandemic H1N1 (pH1N1) influenza posed an increased risk of severe illness among pregnant women. Data on risk factors associated with death of pregnant women and neonates with pH1N1 infections are limited outside of developed countries.</p> <p>Methods</p> <p>Retrospective observational study in 394 severe or critical pregnant women admitted to a hospital with pH1N1 influenza from Sep. 1, 2009 to Dec. 31, 2009. rRT-PCR testing was used to confirm infection. In-hospital mortality was the primary endpoint of this study. Univariable logistic analysis and multivariate logistic regression analysis were used to investigate the potential factors on admission that might be associated with the maternal and neonatal mortality.</p> <p>Results</p> <p>394 pregnant women were included, 286 were infected with pH1N1 in the third trimester. 351 had pneumonia, and 77 died. A PaO<sub>2</sub>/FiO<sub>2 </sub>≤ 200 (odds ratio (OR), 27.16; 95% confidence interval (CI), 2.64-279.70) and higher BMI (i.e. ≥ 30) on admission (OR, 1.26; 95% CI, 1.09 to 1.47) were independent risk factors for maternal death. Of 211 deliveries, 146 neonates survived. Premature delivery (OR, 4.17; 95% CI, 1.19-14.56) was associated neonatal mortality. Among 186 patients who received mechanical ventilation, 83 patients were treated with non-invasive ventilation (NIV) and 38 were successful with NIV. The death rate was lower among patients who initially received NIV than those who were initially intubated (24/83, 28.9% vs 43/87, 49.4%; <it>p </it>= 0.006). Septic shock was an independent risk factor for failure of NIV.</p> <p>Conclusions</p> <p>Severe hypoxemia and higher BMI on admission were associated with adverse outcomes for pregnant women. Preterm delivery was a risk factor for neonatal death among pregnant women with pH1N1 influenza infection. NIV may be useful in selected pregnant women without septic shock.</p
Interpelaciones identitarias en el trabajo: Propuesta para la comprensión de los procesos de construcción de la identidad laboral
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