Silicon nanonets for biological sensing applications with enhanced optical detection ability.

Optical sensors based on fluorescence methods are used in numerous areas of society, ranging from healthcare to environmental monitoring. But the race to elaborate portable and highly sensitive detection systems leads to the huge development of nanomaterial-based sensors. Here, we have fabricated a silicon nanonet, or silicon nanowire (SiNW) network, -based biosensor for DNA hybridization detection by fluorescence microscopy. We demonstrate that by leveraging the properties of the SiNWs such as their large specific surface and the high aspect ratio, these nanonet sensors have significantly enhanced sensitivity and better selectivity compared to plane substrates. The fluorescence signal shows an intensity increasing with the SiNW density on the nanonet and for the denser nanonets, the detection limit for DNA hybridization is 1 nM. The elaborated Si nanonet-based DNA sensors present more than 50% change in fluorescence intensity between complementary DNA and 1 base mismatch DNA which shows their high selectivity. Finally, we have integrated the Si nanonet-based sensor into a DNA chip and we have shown that this selective sensor can be reproduced on a large scale area.

Prevalence of human immunodeficiency virus and hepatitis C virus among French prison inmates in 2010: a challenge for public health policy.

We evaluated prevalence of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) among prison inmates in France in 2010, in a cross-sectional single-day study based on a two-stage design. Sampling favoured larger establishments and included all types of prisons. Establishments were stratified by geographical region. Estimates were adjusted by post-stratification of the total population of inmates in France. From 60,975 inmates in all 188 prisons on the sampling day, 2,154 were selected from 27 prisons, and 1,876 questionnaires completed. HIV prevalence was estimated at 2.0% (95% confidence interval (CI): 0.9­4.2), 2.6% (95% CI: 0.7­8.8) in women and 2.0% (95% CI: 0.9­4.3) in men; 75% of inmates were receiving treatment for HIV. HCV prevalence was estimated at 4.8% (95% CI: 3.5­6.5) and was higher for women (11.8%; 95% CI: 8.5­16.1) than men (4.5%; 95% CI: 3.3­6.3). Almost half of HCV-infected inmates had chronic hepatitis C and 44% were receiving or had received treatment. HIV and HCV prevalence was six times higher than in the general population, and 2.5% of inmates had viraemic hepatitis C. The moment of incarceration provides an ideal opportunity for testing and treating, limiting spread of HCV and improving patients' prognosis.

Kinetics of adventitial repair in the rat carotid model.

BACKGROUND: Discrepancies between success in experimental animals with a variety of pharmacologic strategies and failure with such agents in clinical trials have raised questions concerning the mechanism of restenosis. Recent observations suggest a potential implication for the adventitial (Adv) layer in neointimal formation. METHODS: The purpose of this study was to examine the Adv changes in the rat carotid artery subjected to balloon injury. These changes were characterized by morphometric, immunohistochemical, and electron microscopy analyses, with special attention devoted to early time-points post-injury. RESULTS: We report that the most important adventitial changes occurred in the first 48 h post-injury. Within 2 h there was extensive cell-loss by apoptosis and oncosis in the Adv and in the media; this was followed by the rapid onset of proliferation and a parallel slow increase in Adv thickening, reaching a maximum at 7 days. We further demonstrate an early migration of these Adv cells to the media and neointima. Moreover, we characterize the Adv cell phenotype with a panel of antibodies. Within 48 h after injury, a population of Adv cells expressed alpha-actin and vinculin with a maximum expression 7 days post-injury. At that time, these Adv cells started to express smooth muscle myosin heavy chain, a specific marker of smooth muscle cells. In parallel, we report an impaired production of elastic fibres in the Adv and medial layer. CONCLUSIONS: We reported a detailed time-course of adventitial changes after rat carotid injury (cell death, proliferation, migration and differentiation) that supports an important role of adventitia in neointima formation.

Electrochemical approach to the mechanism of urea denaturation of horse heart cytochrome c.

The effect of urea denaturation on the electroactivity of horse heart cytochrome c has been studied by differential pulse polarography and cyclic voltammetry at a gold electrode; the gold electrode was activated by 4,4'-bipyridine. Essentially, two redox couples with E'01 approximately equal to 0.25 V and E'02 approximately equal to -0.05 V (vs. normal hydrogen electrode) have been detected. The experimental results have been interpreted on the basis of the existence of equilibria between native and denatured electroactive forms; transitory species have been assumed to appear on reduction. The scheme that we have proposed agrees well with the conclusions obtained previously by other authors on conformational changes. Moreover, the advantage of electrochemical techniques in investigating the denaturation process has been underlined.