نتایج جستجو برای: ultraviolet irraciation

تعداد نتایج: 40519  

Journal: :iranian journal of public health 0
mohammad hadi dehghani dept. of environmental health engineering, school of public health, tehran university of medical sciences, tehran, iran ; tehran university of medical sciences, center for solid waste research (cswr), institute for environmental research (ier), tehran, iran. gholam-reza jahed ahmad zarei

rhabditidae is a family of free-living nematodes. free living nematodes due to their active movement and resistance to chlorination, do not remove in conventional water treatment processes thus can be entered to distribution systems and cause adverse health effects. ultraviolet radiation (uv) can be used as a method of inactivating for these organisms. this cross sectional study was done to inv...

Journal: :The Journal of investigative dermatology 2001
D X Nghiem N Kazimi G Clydesdale H N Ananthaswamy M L Kripke S E Ullrich

The ultraviolet radiation present in sunlight is the primary cause of nonmelanoma skin cancer and has been implicated in the development of cutaneous malignant melanoma. In addition, ultraviolet is immune suppressive and the suppression induced by ultraviolet radiation has been identified as a risk factor for skin cancer induction. Ultraviolet also suppresses the immune response to infectious a...

2015
Jin Liu Wei Zhang

OBJECTION The aim of this study is to determine the effect of clothing and the environment on human exposure to ultraviolet light. METHODS The ultraviolet (ultraviolet A and ultraviolet B) light intensity was measured, and air quality parameters were recorded in 2014 in Beijing, China. Three types of clothing (white polyester cloth, pure cotton white T-shirt, and pure cotton black T-shirt) we...

2014
Yoshihiko Muramoto Masahiro Kimura Suguru Nouda

Ultraviolet light-emitting diodes (UV-LEDs) have started replacing UV lamps. The power per LED of high-power LED products has reached 12 W (14 A), which is 100 times the values observed ten years ago. In addition, the cost of these high-power LEDs has been decreasing. In this study, we attempt to understand the technologies and potential of UV-LEDs.

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...

2013
Xinzhang Song Changhui Peng Hong Jiang Qiuan Zhu Weifeng Wang

Ultraviolet-B (UV-B) exposure in the course of litter decomposition may have a direct effect on decomposition rates via changing states of photodegradation or decomposer constitution in litter while UV-B exposure during growth periods may alter chemical compositions and physical properties of plants. Consequently, these changes will indirectly affect subsequent litter decomposition processes in...

Background and purpose: Despite growing use of energy-saving lamps or compact fluorescent lamps (CFLs), there are concerns about ultraviolet radiation in their output. In this study, the output of CFLs available in Iranian market in the range of infrared, visible, and ultraviolet were measured and the possibility of hydroxyl radical production by their radiation was evaluated. Materials and me...

Journal: :Journal of bacteriology 1964
R F HILL

Hill, Ruth F. (Columbia University, New York, N.Y.). Relationship between ultraviolet sensitivity and ability to propagate ultraviolet-irradiated bacteriophage. J. Bacteriol. 88:1283-1287. 1964.-Mutants with a reduced ability to propagate ultraviolet-damaged bacteriophage T(1) were isolated from Escherichia coli strain B/r. The change in this ability varied from a slight to a very marked loss; ...

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: :The Journal of experimental biology 2001
P G Kevan L Chittka A G Dyer

Ultraviolet is an important component of the photic environment. It is used by a wide variety of animals and plants in mutualistic communication, especially in insect and flower inter-relationships. Ultraviolet reflections and sensitivity are also becoming well considered in the relationships between vertebrates and their environment. The relative importance of ultraviolet vis à vis other prima...

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