نتایج جستجو برای: ultraviolet b

تعداد نتایج: 933118  

The present study was focused to examine the combined effects of climate and ultraviolet-B radiation on conifer tree-ring density. Statistical methods were employed to extract tree responses in annual ring density and to identify functional relationship in trees when the level of ultraviolet-B radiation changes regardless of climate variations. In this study, the consideration was given to the ...

Journal: :novelty in biomedicine 0
mohammadreza nazari department of optometry, faculty of rehabilitation sciences, shahid beheshti university of medical sciences, tehran, iran saeed rahmani department of optometry, faculty of rehabilitation sciences, shahid beheshti university of medical sciences, tehran, iran bahram khosravi department of optometry, faculty of rehabilitation sciences, shahid beheshti university of medical sciences, tehran, iran seyyed mehdi tabatabaei

background: wearing spectacles is the most common approach in correcting the refractive errors worldwide. due to harmful effects of overexposure to solar ultraviolet radiations, the usage of multi-layer coatings in ophthalmic lenses has recently been increased. these lenses can reduce the reflections and hence increase the transmission of visible light; they can also decrease the transmission o...

ژورنال: پژوهش در پزشکی 2011
رحمنی, سعید, طباطبایی, سید مهدی, قاسمی برومند, محمد, نظری, محمدرضا ,

Abstract Background: Solar light has various electromagnetic radiations include Ultraviolet, Visible & infrared rays. Overexposure to solar ultraviolet radiations can lead to some dangerous disorders and usage of non standard sunglasses can increase foregoing harmful effects. In Iran cataract is the most common disorder produced by UV rays. This study aims to measure the transmission of ultr...

Journal: :علوم گیاهان زراعی ایران 0
حمیدرضا بلوچی سید علی محمد مدرس ثانوی یحیی امام

drought, ultraviolet radiation and atmospheric co2 are some three environmental factors that seriously affect future food security. the objective followed in the present research was to study the effect of two levels of carbon dioxide (400 and 900 ppm), ultraviolet radiation (uv a, b and c with intensities of 18, 25 and 40 microw.cm-2 respectively) and water deficit (%100 and %60 of field capac...

Journal: :Plant physiology 1981
R P Trocine J D Rice G N Wells

Effects of ultraviolet-B radiation on the photosynthesis of seagrasses (Halophila engelmanni Aschers, Halodule wrightii Aschers, and Syringodium filiforme Kütz) were examined. The intrinsic tolerance of each seagrass to ultraviolet-B, the presence and effectiveness of photorepair mechanisms to ultraviolet-B-induced photosynthetic inhibition, and the role of epiphytic growth as a shield from ult...

Journal: :The Journal of investigative dermatology 2002
Dat X Nghiem Nasser Kazimi David L Mitchell Arie A Vink Honnavara N Ananthaswamy Margaret L Kripke Stephen E Ullrich

The ultraviolet radiation present in sunlight is immune suppressive. Recently we showed that solar-simulated ultraviolet radiation (ultraviolet A + B; 295-400 nm), applied after immunization, suppressed immunologic memory and the elicitation of delayed-type hypersensitivity to the common opportunistic pathogen, Candida albicans. Further, we found that wavelengths in the ultraviolet A region of ...

Journal: :Planta medica 2015
Hiroko Maruyama Hidekazu Tamauchi Fumitaka Kawakami Keiko Yoshinaga Takahisa Nakano

It is well known that ultraviolet B irradiation leads to dermal inflammation. In this study, we found that Mekabu fucoidan suppressed edema, decreased the thickness of the prickle cell layer, and decreased matrix metalloproteinase 1 in the skin of mice irradiated with ultraviolet B. Moreover, we found that the mean level of interferon gamma of Mekabu fucoidan-treated, ultraviolet B-irradiated m...

Journal: :Journal of cell science 2005
Momchil D Vodenicharov Medini M Ghodgaonkar Sabina S Halappanavar Rashmi G Shah Girish M Shah

The damage to DNA caused by ultraviolet B radiation (280-320 nm) contributes significantly to development of sunlight-induced skin cancers. The susceptibility of mice to ultraviolet B-induced skin carcinogenesis is increased by an inhibitor of the DNA damage-activated nuclear enzyme poly(ADP-ribose) polymerase-1 (PARP), hence PARP activation is likely to be associated with cellular responses th...

Journal: :تحقیقات نظام سلامت 0
شهرام صفری دانشجوی کارشناسی ارشد، گروه مهندسی بهداشت حرفه ای، دانشکده بهداشت، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران مقداد کاظمی دانشجوی کارشناسی ارشد، گروه مهندسی بهداشت حرفه ای، دانشکده بهداشت، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران حبیب الله دهقان استادیار، گروه مهندسی بهداشت حرفه ای، دانشکده بهداشت، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران حسینعلی یوسفی مربی، گروه مهندسی بهداشت حرفه ای، دانشکده بهداشت، دانشگاه علوم پزشکی اصفهان، اصفهان،ایران بهزاد مهکی استادیار، گروه آمار و اپیدمیولوژی، دانشکده بهداشت، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران

background : one way to optimize energy consumption is replacing incandescent lamp with compact fluorescent lamps .these lamps produce ultraviolet radiation due to the nature of light production. this study aimed to evaluate the ultraviolet radiation emitted from compact fluorescent lamps which are widely used in iran. methods : this study carries out on 16 compact fluorescent lamps (four diffe...

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