نتایج جستجو برای: uv b
تعداد نتایج: 961435 فیلتر نتایج به سال:
The ciliary zonules link the lens to the ciliary body in the eye, controlling the thickness of the lens for focusing through their characteristic elasticity. The ciliary zonules are composed of oxytalan fibers. Physiological or pathological damage to the ciliary zonules, including exposure to ultraviolet (UV)-A and UV-B components, can lead to lens dislocation. However, no studies have shown wh...
The potential impact of an increase in solar ultraviolet-B (UV-B) radiation due to human activity on higher plants has been the subject of many studies. Little work has been carried out so far on cotton responses to enhanced UV-B radiation. The objective of this study was to determine whether or not the current and projected increases in UV-B levels affect cotton growth and development, and to ...
The effects of irradiating blue, UV-A, UV-B and a combination of the lights on anthocyanin accumulation at different hypocotyl positions were investigated in seedlings of the purple top turnip 'Tsuda'. The location of anthocyanin accumulation varied depending on different light spectra. Stronger accumulation of anthocyanin was induced (i) at the upper hypocotyl positions by blue light; (ii) mai...
In a field experiment, the effect of enhanced UV-B radiation (simulating 20% ozone depletion at Allahabad, 20 degrees 47' N latitude) was studied on two cultivars of Vigna radiata L. with various levels of mineral nutrients (N and P). Study showed decrease in total biomass accumulation, harvest index, RSR and yield after exposure with enhanced level of UV-B. RGR and CGR also showed decline afte...
We wondered whether the apoptosis known to occur after UV-B irradiation might involve the Fas/Fas ligand (FasL) signaling pathway. We exposed PBLs from normal individuals, and also the Jurkat (E6-1) and U937 cell lines, to graded doses of UV-B irradiation and observed a prompt and marked increase in Fas expression at doses as low as 0.5 mJ/cm2. Increased Fas expression did not require new prote...
UV radiation has been shown to play a role in the initiation of human cutaneous melanoma, but its role in the development of malignant melanoma to the metastatic state is not very well defined. Although previous studies have concentrated on the effect of UV-B on the host immune response, the effect of UV-B on the tumor cells was not elucidated. Here we show that UV-B can induce interleukin 8 (I...
Stress induced by ultraviolet-B (UV-B) irradiation stimulates the accumulation of various secondary metabolites in plants. Nitric oxide (NO) serves as an important secondary messenger in UV-B stress-induced signal transduction pathways. NO can be synthesized in plants by either enzymatic catalysis or an inorganic nitrogen pathway. The effects of UV-B irradiation on the production of baicalin an...
AIMS To assess the variability in UV-B (280-320 nm) sensitivity of selected bacterial isolates from the surface microlayer and underlying water of the Ria de Aveiro (Portugal) estuary and their ability to recover from previous UV-induced stress. METHODS AND RESULTS Bacterial suspensions were exposed to UV-B radiation (3·3 W m⁻²). Effects on culturability and activity were assessed from colony...
موضوع تحقیق حاضر، مطالعهی اثر تنش خشکی، اشعهی UV-Bو اثرات ترکیبی تنشهای UV-B و خشکی بر روی دو رقم گیاه کدو (مشهدی و همدانی) میباشد. گیاهان کدو به مدت 14 روز با دورهی 16 ساعت روشنایی و 8 ساعت تاریکی و در دمای C º 26/22 ( شب/روز) ، میزان رطوبت نسبی 60%و شدت نورmol.m-2.s µ150 کشت داده شدند، سپس گیاهان 25 روزه به 4 گروه تقسیم شدند. گروه کنترل و 3 گروه برای مطالعه در شرایط تنش UV-Bهر روز به مد...
Phototherapy with ultraviolet (UV) irradiation of wavelengths between 280 and 320 nm (UV-B) is a safe and effective treatment for a variety of inflammatory skin diseases. In addition to standard broad band UVB, narrow band phototherapy with fluorescent bulbs emitting near monochromatic UV between 310-315 nm has become an important treatment for diseases such as psoriasis, atopic dermatitis or v...
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