Azophenol-based liquid-crystalline elastomers for light-driven actuators.

Para-substituted azophenols exhibit a fast thermal cis-to-trans isomerization rate in ethanol, which can be transferred to the solid state by obtaining liquid-crystalline elastomeric systems. The absence of protic solvent is compensated by the establishment of hydrogen bonding between azophenol monomers that are close to each other. Opto-mechanical experiments reveal that azophenol-containing liquid single-crystal elastomers are valuable materials for light-controlled actuators exhibiting relaxation times of 1 s at room temperature.

Effectiveness and acceptability of vitamin E and low-dose aspirin, alone or in combination, on Norplant-induced prolonged bleeding.

A study (ISRCTN 77665712) was undertaken to test the effectiveness and the acceptability of vitamin E and low-dose aspirin, alone or in combination, as treatment for prolonged vaginal bleeding induced by Norplant. A total of 486 Norplant users who were requesting treatment for bleeding lasting longer than 7 days were enrolled in five centers: Beijing, China; Jakarta, Indonesia; Santiago, Chile; Santo Domingo, Dominican Republic; and Tunis, Tunisia. They were randomized to one of four different 10-day oral treatments: 200 mg vitamin E daily, 80 mg aspirin daily, both or a placebo.

Managing data for a multicountry longitudinal study: experience from the WHO Multicentre Growth Reference Study.

The World Health Organization (WHO) Multicentre Growth Reference (MGRS) data management protocol was designed to create and manage a large data bank of information collected from multiple sites over a period of several years. Data collection and processing instruments were prepared centrally and used in a standardized fashion across sites. The data management system contained internal validation features for timely detection of data errors, and its standard operating procedures stipulated a method of master file updating and correction that maintained a clear trail for data auditing purposes.

The reporting of methods for reducing and detecting bias: an example from the WHO Misoprostol Third Stage of Labour equivalence randomised controlled trial.

Background: The aim of this article is to explore ways in which selection bias and ascertainment bias can be reduced and investigated in trials, by using the example of a drug trial carried out in both developed and developing countries in hospital delivery wards.

Methods: We describe an innovative and practical design for the boxes for packing the drugs as a way of increasing the security of allocation concealment and blinding. We also assess ascertainment bias using sensitivity analyses, as some unblinding could have occurred due to a potential side effect of one of the drugs.

The epidemiology of syphilis in pregnancy.

This study evaluated the magnitude, risk factors and outcomes of syphilis in pregnancy in a large cohort of women in four countries participating in the World Health Organization (WHO) antenatal care trial. All women attending the first prenatal care at each selected clinic were enrolled. Screening at the first antenatal visit was routinely performed with either rapid plasma reagin or Venereal Disease Research Laboratory and confirmed by fluorescent treponemal antibody absorption.