Search results for "sunlight"

Simulated solar UV-irradiation of endocrine disrupting chemical octylphenol.

2009

The photolysis of octylphenol (OP) was investigated using a solar simulator in the absence/presence of dissolved natural organic matter (DNOM), HCO(3)(-), NO(3)(-) and Fe(III) ions. The effects of different parameters such as initial pH, initial concentration of substrate, temperature, and the effect of hydrogen peroxide concentration on photodegradation of octylphenol in aqueous solution have been assessed. The results indicate that the oxidation rate increases in the presence of H(2)O(2), nitrate and DNOM. Phenol, 1,4-dihydroxylbenzene and 1,4-benzoquinone were identified as intermediate products of photodegradation of octylphenol, through an HPLC method. In addition, the disappearance of…

Sun radiation and temperature impact at different periods of the year on the photooxidation of polyethylene films

2017

Analysis of the IR spectra of weathered films exposed at different periods of the year reveals that, the main regions of the IR spectrum affected by solar irradiation and temperature variation are the complex carbonyls and unsaturations composite absorption bands. Their respective kinetics vary in different manner according to the period at which the exposure is started. Curve fitting has been performed to refine the analysis of the IR spectra and to identify all the chemical species constituting the complex absorption bands. The analysis of the results let appears that whatever the exposure period of the year is, it does not affect the type of developing products, but it has strong effect …

Vitamin D deficiency and leisure time activities in the elderly: are all pastimes the same?

2014

Background Optimal vitamin D status is important for overall health and well-being, particularly in the elderly. Although vitamin D synthesis in the skin declines with age, exposure to sunlight still seems to help older-aged adults to achieve adequate serum 25-hydroxyvitamin D (25OHD) levels. Elderly people would therefore benefit from outdoor leisure activities, but the effects of different types of pastime on serum 25OHD levels have yet to be thoroughly investigated. Aims To assess the association of different pastimes with 25OHD deficiency in elderly subjects. Methods A sample of 2,349 community-dwelling elderly individuals (1,389 females and 960 males) enrolled in the Progetto Veneto An…

Effect of artificial shading on the tannin accumulation and aromatic composition of the Grillo cultivar (Vitis vinifera L.)

2013

Abstract Background White wine quality, especially in warm climates, is affected by sunlight and heat stress. These factors increase the probability that ambering processes will occur and reduce the potential flavour compounds. This study aimed to investigate the effect of sunlight reduction on the accumulation of polyphenolic and aromatic compounds. Results This study was conducted in a commercial vineyard containing V. vinifera L. cv Grillo. Opaque polypropylene boxes (100% shading) and high-density polyethylene (HDPE) net bags (50% shading) were applied at fruit set. The effect of the shaded treatments was compared to the exposed fruit treatment. The shaded treatments resulted in heavier…

Effect of the relative optical air mass and the clearness index on solar erythemal UV irradiance

2014

This paper analyses the effects of the clearness index (Kt) and the relative optical air mass (mr) on erythemal UV irradiance (UVER). The UVER measurements were made in Valencia (Spain) from 6:00 am to 6:00 pm between June 2003 and December 2012 and (140,000 data points). Firstly, two models were used to calculate values for the erythemal ultraviolet irradiance clearness index (KtUVER) as a function of the global irradiance clearness index (Kt). Secondly, a potential regression model to measure the KtUVER as a function of the relative optical air mass was studied. The coefficients of this regression were evaluated for clear and cloudy days, as well as for days with high and low ozone levels…

Sun exposure and PDZK1 genotype modulate PDZK1 gene expression in normal skin

2020

Human skin pigmentation results from the enzymatically controlled synthesis of melanin pigments in specialized organelles (melano‐somes) produced within epidermal melanocytes, followed by their transfer to neighboring keratinocytes and their distribution through‐out the epidermis.1 Constitutive skin pigmentation seems to be mostly genetically determined,2 being altered by numerous intrinsic and extrinsic factors affecting the epidermal melanin unit

Sex and MC1R variants in human pigmentation: Differences in tanning ability and sensitivity to sunlight between sexes

2016

Seasonal variation of BMI at admission in German adolescents with anorexia nervosa.

2018

Objective Recent preliminary studies indicated a seasonal association of BMI at admission to inpatient treatment for anorexia nervosa (AN), indicating lower BMI in the cold season for restrictive AN. An impaired thermoregulation was proposed as the causal factor, based on findings in animal models of AN. However, findings regarding seasonality of BMI and physical activity levels in the general population indicate lower BMI and higher physical activity in summer than in winter. Therefore, we aimed to thoroughly replicate the findings regarding seasonality of BMI at admission in patients with AN in this study. Method AN subtype, age- and gender-standardized BMI scores (BMI-SDS) at admission, …

Occupational sun exposure and mycosis fungoides: a European multicenter case-control study.

2006

International audience; OBJECTIVE: We sought to study the association between occupational sun exposure and mycosis fungoides (MF), a peripheral T-cell lymphoma. SUBJECTS AND METHODS: A European multicenter case-control study including seven rare cases (one being MF) was conducted between 1995 and 1997. From the 118 accepted cases, 104 were interviewed, of which 76 were definite cases. Population controls were selected randomly from the regions of case ascertainment. Information based on occupational experiences was coded according to industry types. A job exposure matrix was created according to the expected exposure to sunlight. RESULTS: Once exposures to aromatic halogenated hydrocarbons…

The Italian Euromelanoma Day: evaluation of results and implications for future prevention campaigns.

2012

Background Melanoma incidence/mortality is increasing worldwide. “Euromelanoma Day” is a pan-European campaign for skin cancer prevention. Results of the 2010 Euromelanoma Day in Italy are reported herein. Materials and methods A questionnaire was used to collect data on participants' characteristics and suspected skin cancers. Result A total of 1085 participants was screened (64.1% females, median age 44 years). Suspicion rate, detection rate, and positive predictive values for melanoma were 1.3, 0.28 and 21.4%, respectively. Poorly educated, ≥35 years old, pale-skinned males were at higher risk for skin cancer than highly educated, <35 years old, darker-skinned females, although the latte…