Disposable indicators for monitoring lighting conditions in museums

Photoinduced alterations of light-sensitive artifacts represent one of the main problems that conservators and curators have to face for environmental control in museums and galleries. Therefore, increasing attention has been recently devoted to developing strategies of indoor light monitoring, especially aimed at minimizing the cumulated light exposure for the objects on exhibit. In this work a prototype of a light dosimeter, constituted by a photosensitive dyes/polymer mixture applied on a paper substrate, is presented. This indicator, specially designed for a preventive assessment of the risk of damage for highly light-sensitive objects, undergoes a progressive color variation as its exposure to the light increases. Different, easily distinguishable color steps are exhibited depending on the light dose received, so that the dosimeter can be used straightforwardly to have a first, instrumentation-free estimation of the total light exposure. A reflectance spectroscopy study in the 350-860 nm range was carried out on prototype dosimeters exposed to light emitted from a tungsten-halogen lamp to investigate the response of the dosimeter to the light and to study the fading mechanism. Two different approaches were evaluated for the calibration of the prototype: colorimetry and principal component analysis of the reflectance spectra. The usefulness of the two methods in providing a quantitative indication of the light dose received was evaluated.     

Proton exchange membrane water electrolysis with short-side-chain Aquivion membrane and IrO2 anode catalyst

A series of three membrane types has been screened for medium temperature solid polymer electrolyte water electrolysis in membrane electrode assemblies coated with 2 mg cm⁻² of iridium oxide as a catalyst for the oxygen evolution reaction, synthesised via a hydrolysis method from the hexachloroiridic acid precursor, and deposited on the membrane either directly by spray deposition or by decal transfer. The short-side-chain perfluorosulfonic acid Aquivion^® ionomer of equivalent weight 870 meq g⁻¹, in membranes of thickness 120 μm, gives higher water electrolysis performance at 120 °C than a composite membrane of Aquivion^® with zirconium phosphate, while a sulfonated ether-linked polybenzimidazole, sulfonated poly-[(1-(4,4′-diphenylether)-5-oxybenzimidazole)-benzimidazole], shows promising performance and no transport limitations up to 2 A cm⁻². The lowest cell voltage was observed at 120 °C for an MEA prepared using spray-coating directly on the Aquivion^® membrane, 1.57 V at 1 A cm⁻².     

Wall temperature experimental investigation in a thermally driven channel

Direct local wall temperature has been measured, in a steady state, along a vertical air channel asymmetrically heated with uniform fluxes. In the range of high Grashof numbers that was investigated, the flow regime probably remained laminar. A radiative part has been analysed with two extreme values of internal surface emissivity corresponding to unpainted metal and black painted wall. A correlation has been proposed for the calculation of a characteristic channel outlet value of the Nusselt number referred to air spacing. A local Nusselt number over the height has been developed in a power law scheme.     

High frequency of nonclassical steroid 21-hydroxylase deficiency

Nonclassical steroid 21-hydroxylase deficiency is an autosomal recessive disorder that is defined by clinical and hormonal criteria that distinguishes it from the classical 21-hydroxylase deficiency. No estimates of the gene frequency of nonclassical 21-hydroxylase deficiency, also called attenuated, late-onset, acquired, and cryptic adrenal hyperplasia, have been published thus far. Here, we have used HLA-B genotype data in families containing multiple members affected with nonclassical 21-hydroxylase deficiency together with the results of quantitative hormonal tests to arrive at estimates of gene and disease frequencies for this disorder. We found nonclassical 21-hydroxylase deficiency to be a far more common disorder than classical 21-hydroxylase deficiency, which occurs in 1/8,000 births. The prevalence of the disease in Ashkenazi Jews was 3.7%; in Hispanics, 1.9%; in Yugoslavs, 1.6%; in Italians, 0.3%; and in the diverse Caucasian population, 0.1%. The gene for nonclassical 21-hydroxylase deficiency is in genetic linkage disequilibrium with HLA-B14 in Ashkenazi Jews, Hispanics, and Italians, but not in Yugoslavs or in a diverse, non-Jewish, Caucasian group. The penetrance of nonclassical 21-hydroxylase deficiency gene in the HLA-B14 containing haplotypes was incomplete. Thus, nonclassical 21-hydroxylase deficiency is probably the most frequent autosomal recessive genetic disorder in man and is especially frequent in Ashkenazi Jews, Hispanics, Italians, and Yugoslavs.     

Allergy to extensively hydrolyzed cow milk proteins in infants: identification and treatment with an amino acid-based formula

OBJECTIVE: To evaluate acetowhite changes of the cervix and vulva as a predictor of human papillomavirus (HPV) infection. METHODS: In this population-based study all women aged 19, 21, 23, and 25 years and registered as living in a primary health care area within the city of Ume?, Sweden were eligible for inclusion. Each participant underwent a gynecologic examination with sampling of epithelial cells for HPV-DNA detection and Papanicolaou smear. Colposcopy was performed 5 minutes after application of 5% acetic acid. A two-step polymerase chain reaction (PCR) technique was employed for HPV-DNA detection. RESULTS: Colposcopy and sampling of epithelial cells could be performed in 535 women. The sensitivity of detection of HPV infection by the acetowhitening of the cervix was 22% (95% confidence interval [CI] 18%, 26%). The specificity of detection of HPV infection by the acetowhitening of the cervix was 90% (95% CI 87%, 93%). The sensitivity of detection of HPV infection by cytology was 13% (95% CI 10%, 16%), and the specificity was 99% (95% CI 98%, 100%). The combination of acetowhitening and cytology did not improve the diagnostic value. CONCLUSION: Acetowhitening of the cervix and vulva has low sensitivity as a predictor of HPV infections as determined by PCR.     

Power and sample size calculations for studies involving linear regression

This article presents methods for sample size and power calculations for studies involving linear regression. These approaches are applicable to clinical trials designed to detect a regression slope of a given magnitude or to studies that test whether the slopes or intercepts of two independent regression lines differ by a given amount. The investigator may either specify the values of the independent (x) variable(s) of the regression line(s) or determine them observationally when the study is performed. In the latter case, the investigator must estimate the standard deviation(s) of the independent variable(s). This study gives examples using this method for both experimental and observational study designs. Cohen's method of power calculations for multiple linear regression models is also discussed and contrasted with the methods of this study. We have posted a computer program to perform these and other sample size calculations on the Internet (see http://www.mc.vanderbilt.edu/prevmed/psintro+ ++.htm). This program can determine the sample size needed to detect a specified alternative hypothesis with the required power, the power with which a specific alternative hypothesis can be detected with a given sample size, or the specific alternative hypotheses that can be detected with a given power and sample size. Context-specific help messages available on request make the use of this software largely self-explanatory.     

Dyeing plants screening: an approach to combine past heritage and present development

The paper reports an investigation of the colouring properties of 43 dyeing plants chosen for their widespread use in previous centuries. Colorimetric analysis showed that the principal colours on different fabric supports were yellow and mostly unsaturated. The nature of the support fibres investigated, protein- or cellulose-based, was shown to play an important role in the perceived colours. Phytochemical analysis confirmed that yellow-orange shades could be attributed to flavonoids and that red colours were due to anthraquinones. Colours from plants that contain anthocyanins varied from blue-violet through reddish depending on the structure of the anthocyanins in the individual plants. Colour fastness was determined by applying standard test methods. Fastness to light appeared to be inadequate for industrial applications for most samples, but it seems that this could be improved by certain molecular associations. On the other hand, colour fastness to water was satisfactory.     

Experimental study of back‐scattering spectrum of textile structures

The back‐scattered light by textile surfaces mainly depends on their surface state, which is often periodic and directional. The analysis of the reflectance spectra in back‐scattering conditions of two types of structures (yarn, plain and twill weaves) shows the influence of the orientation of these surfaces as well as the back‐scattered angle. In fact, the declination of the yarn orientation in relation to the incidence plane involves an increase of the reflectance factor to reach a maximum value when the yarns are perpendicular to this plane. For woven fabrics, the back‐scattering of surface according to a given orientation primarily depends on its geometrical characteristic in this direction and consequently the used yarn densities. The computation of the ratio of mean quadratic surface roughness h to correlation length l for various used orientations shows the close link between this parameter and the evolution of back‐scattering. The effect of the variation of back‐scattered angle on the back‐scattered light varies with the value of h/l . The comparison between these experimental results and a theoretical study based on Gaussian and isotropic surfaces shows a satisfactory correlation between these two elements with the presence of some cases of discrepancy due to the different natures of the two types of surfaces. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 122–132, 2006