WorldWideScience

Sample records for long-wave ultraviolet puva

  1. Effect of 8-methoxypsoralen plus long-wave ultraviolet (PUVA) radiation on mast cells. II. In vitro PUVA inhibits degranulation of rat peritoneal mast cells induced by compound 48/80

    International Nuclear Information System (INIS)

    Toda, K.; Danno, K.; Tachibana, T.; Horio, T.

    1986-01-01

    Rat peritoneal mast cells incubated with a histamine liberator, compound 48/80, showed a significantly reduced capacity for releasing histamine following in vitro treatment with 0.1 micrograms/ml of 8-methoxypsoralen (8-MOP) plus 1-5 J/cm2 of long-wave ultraviolet (UVA) irradiation (PUVA). No remarkable inhibition in histamine release was observed in the cells treated with 8-MOP only. Irradiation with 5 J/cm2 of UVA alone exerted an inhibitory effect on histamine release, to a lesser extent than PUVA. PUVA irradiation did not bring any decrease in cell viability or any spontaneous release of histamine from irradiated cells as shown by phase-contrast microscopy and by histamine assay, respectively. These results suggest that PUVA treatment may cause a noncytotoxic disturbance at mast cell membranes or on surface receptors, leading to a decreased capacity for secreting chemical mediators

  2. Ultrastructural modification of the plasma membrane in HUT 102 lymphoblasts by long-wave ultraviolet light, psoralen, and PUVA

    International Nuclear Information System (INIS)

    Malinin, G.I.; Lo, H.K.; Hornicek, F.J.; Malinin, T.I.

    1990-01-01

    Ultrastructural alterations of the plasma membrane in HUT 102 lymphoblasts were assessed after a 2-h interaction with a suprapharmacologic (15 micrograms/ml) concentration of 8-MOP, 2-h irradiation with UVA (2.1 mW/cm2), and the exposure of the HUT 102 cells to PUVA under the same conditions. The dark reaction of HUT cells with 8-MOP resulted in the disappearance of microvilli, the emergence of plasma-membrane-associated spherical bodies, formation of lamellar fungiform membrane evaginations, and, in approximately 1% of the cells, formation of uropods and cell capping. Except for uropod formation and cell capping, UVA has induced the same plasma-membrane alterations, and was more deleterious to structural cytoplasmic integrity than 8-MOP. Morphologic changes of the plasma membrane in PUVA-exposed cells tended to replicate structural alterations elicited independently during the dark reaction by suprapharmacologic 8-MOP concentrations. Partial retention of microvilli by cells after PUVA was the sole exception. In light of all available evidence we conclude that psoralen during the dark reactions interacts with plasma membrane lipids by as yet undisclosed mechanisms and that in addition to lipids, membrane proteins are also the primary target of the initial interaction of HUT 102 cells with psoralen during PUVA treatment

  3. Influence of a transfusion of donor leukocytes treated with 8-methoxypsoralen and long-wave ultraviolet light (PUVA) on skin allograft survival in mice

    International Nuclear Information System (INIS)

    Gruner, S.; Noack, F.; Meffert, H.

    1989-01-01

    The influence of pretransplant donor spleen cell infusions on murine skin graft survival was studied. In dependence on the time interval between transplantation and transfusion an accelerated or delayed rejection of the grafts was observed. If the donor spleen cells were treated with the photosensitizer 8-methoxypsoralen and UVA light (PUVA) a graft prolongation was achieved at all time intervals. Furthermore, the survival of antigenically unrelated grafts was also prolonged. An additional immunosuppressive treatment of the recipients with antilymphocyte serum, but not cyclophosphamide, led to a further prolongation of graft survival. The survival of PUVA treated skin grafts was not longer in recipients preinfused with PUVA treated donor cells compared with untreated hosts. The results presented in this work may have implications in clinical organ transplantation to prevent sensitizing reactions by sparing protective mechanisms for the graft. (author)

  4. Mutagenicity of 8-methoxypsoralen and long-wave ultraviolet irradiation in V-79 Chinese hamster cells

    International Nuclear Information System (INIS)

    Burger, P.M.; Simons, J.W.I.M.

    1979-01-01

    The effect of 8-methoxypsoralen (8-MOP) and long-wave ultraviolet irradiation (UVA) on cell killing and mutation induction was studied in V-79 Chinese hamster cells. No effect was observed after treatment with 8-MOP alone (50 μg/ml, 4 h), UVA alone (9000 J/m 2 ), or 8-MOP metobolized by rat-liver microsomes. Combined treatment with 8-MOP and UVA induced both cell killing and mutation. This was also observed under conditins approaching patient treatment with PUVA photochemotherapy with respect to the concentration of 8-MOP in the skin and the amount of UVA received by the epidermal cells. A simple relation proved to apply for mutation induction under different treatment conditions: 5.5 X 10 -8 per J/m 2 per μg 8-MOP/ml. On this basis the mutation induction in dividing cells per session of PUVA-photochemotherapy amounts to 12.4 X 10 -5 , which is probably an over-estimation. (Auth.)

  5. Alteration of lymphocyte functions by 8-methoxypsoralen and longwave ultraviolet radiation. I. Suppressive effects of PUVA on T-lymphocyte migration in vitro

    International Nuclear Information System (INIS)

    Okamoto, H.; Takigawa, M.; Horio, T.

    1985-01-01

    We investigated the influence of 8-methoxypsoralen (8-MOP) plus long-wave ultraviolet radiation (PUVA) on lymphocyte migration in vitro. Nylon wool-purified, mouse splenic T lymphocytes showed locomotive responses to casein, normal mouse serum (NMS), and zymosan-activated mouse serum (ZAS). Migratory responses to casein and NMS, and to ZAS were remarkably suppressed in lymphocytes exposed to 0.5 J/cm2 UVA plus 0.1 micrograms/ml 8-MOP and to 0.8 J/cm2 UVA plus 8-MOP, respectively. The PUVA treatment used in the present study had no effect on random movement and lymphocyte viability. T lymphocytes cultured in the absence of mitogenic agent for 24 h demonstrated a greater increase in their migration activity than noncultured cells, while lymphocytes cultured after 1.0 J/cm2 PUVA pretreatment remained low. These findings suggest that the therapeutic effect of PUVA on inflammatory skin disorders may be due in part to the suppression of lymphocyte migration

  6. Psoralen plus ultraviolet A (PUVA soaks and UVB TL01 treatment for chronic hand dermatoses

    Directory of Open Access Journals (Sweden)

    Lisbeth Jensen

    2012-02-01

    Full Text Available Chronic eczematous hand dermatoses with and without contact allergies are complex diseases, which makes it a challenge to select the best treatment and obtain an optimal patient experience and a satisfactory treatment result. The aim of this study was to evaluate retrospectively the clinical effect and patient experience of local treatment with psoralen plus ultraviolet A (PUVA soaks and TL01 phototherapy for severe chronic hand dermatoses, and also to evaluate the quality of life for the subgroup of patients with allergic contact dermatitis including Compositae allergy. A retrospective evaluation of results for 94 consecutive patients having received a total of 121 treatment courses with local PUVA soaks or TL01 phototherapy for one of the following diagnoses (n=number of treatment courses: psoriasis (n=19, hyperkeratotic hand eczema (n=27, Pustulosis Palmoplantaris (PPP (n=22, vesicular eczema (n=16, Compositae dermatitis (n=24, and allergic contact dermatitis (n=13. Moreover, semi-structured interviews with 6 selected patients having multiple contact allergies including Compositae allergy were used to evaluate quality of life. As a result, we found that PUVA soaks has good effect in patients with psoriasis and hyperkeratotic hand eczema and local phototherapy for chronic hand dermatoses is a useful treatment option in selected cases.

  7. Effects of PUVA on the eye

    International Nuclear Information System (INIS)

    Backman, H.A.

    1982-01-01

    Psoriasis is a common skin disease which may be treated with 8-methoxy psoralen and long-wave ultraviolet light (PUVA). Eye protection is provided during and after treatment to prevent the development of photokeratitis and cataracts. Fifteen patients, treated with medication and ultraviolet A (UVA) had an initial complete eye examination and a repeat examination after each treatment. No patients developed cataracts but almost one-half of the patients had a mild form of photokeratoconjunctivitis. The ocular manifestations included photophobia, conjunctivitis, keratitis, and dry eyes. Tear break-up time was reduced significantly immediately after treatment for two patients but returned to normal 8 hr later. Dermatologists who employ PUVA treatments should be concerned about photokeratoconjunctivitis and the dry-eye ocular manifestations included photophobia, conjunctivitis, keratitis, and dry eyes. Tear break-up time was reduced significantly immediately after treatment for two patients but returned to normal 8 hr later. Dermatologists who employ PUVA treatments should be concerned about photokeratoconjunctivitis and the dry-eye ocular manifestations included photophobia, conjunctivitis, keratitis, and dry eyes. Tear break-up time was reduced significantly immediately after treatment for two patients but returned to normal 8 hr later. Dermatologists who employ PUVA treatments should be concerned about photokeratoconjunctivitis and the dry-eye syndrome

  8. DNA repair synthesis in human skin exposed to ultraviolet radiation used in PUVA (psoralen and UV-A) therapy for psoriasis

    International Nuclear Information System (INIS)

    Bishop, S.C.

    1979-01-01

    The ultraviolet radiation used in psoralen and UV-A (PUVA) therapy stimulated DNA repair activity in normal human skin and in the uninvolved skin from psoriatic patients. The activity detected by autoradiography increased linearly with exposure time. No stimulation was observed when the UV-B component was removed from the incident radiation by filtration through glass. Therefore UV-B damage to DNA was found responsible for the activity detected following exposure to the unfiltered PUVA light source. (author)

  9. Autoradiographical in-vitro examination of the cell proliferation of persisting psoriatic plaques in preferred areas under therapy with ultraviolet light: Photochemotherapy (PUVA) and selective ultraviolet phototherapy (SUP)

    International Nuclear Information System (INIS)

    Middendorf, M.

    1982-01-01

    The application of ultraviolet rays (PUVA, SUP) brought significant progress in the treatment of psoriasis. The goal of UV-irradiation is to normalise the epidermal growth conditions. The cell cycle of persisting psoriatic plaque in preferred areas was examined under therapy with PUVA and SUP using an autoradiographic in-vitro method, double labelling with 14 C- and 3 H-thymididin. The results were compared to the known cell-kinetic parameters of psoriasis. The values thus obtained confirm the characteristic changes in the cell cycle of psoriasis. Furthermore, there is a block within the DNA-synthesis phase in the plaques persisting under UV-therapy. The resistence of persisting psoriatic plaques in preferred regions against UV-therapy is regarded as an indication of an extreme disturbance in the proliferation behaviour of the psoriatic skin. (orig./MG) [de

  10. Biologic changes due to long-wave ultraviolet irradiation on human skin: ultrastructural study

    International Nuclear Information System (INIS)

    Kumakiri, M.; Hashimoto, K.; Willis, I.

    1977-01-01

    Alteration of the skin induced by single and repeated long-wave ultraviolet (UVA) exposures was studied. Following a single exposure to relatively large doses of UVA, pronounced dermal damage was observed. In the papillary dermis, superficial dermal vessels showed widely open endothelial gaps and extravasation of blood cells. Marked changes of fibroblasts were also seen in the superficial dermis. In the reticular dermis, extravascular fibrin deposition was seen. After repeated exposures to UVA the formation of cross-banded filamentous aggregations (''Zebra bodies'') was observed in the superficial and reticular dermis. These were often found in amorphous masses surrounding the blood vessels. These striking dermal alterations were absent in skin irradiated by solar stimulating radiation and in control skin. Dyskeratotic ''sunburn cells'' were occasionally seen in the epidermis after single as well as repeated exposures to UVA. The number of these cells was less than that seen after a single exposure to solar simulating radiation

  11. Long-wave ultraviolet light induces phospholipase activation in cultured human epidermal keratinocytes

    International Nuclear Information System (INIS)

    Hanson, D.; DeLeo, V.

    1990-01-01

    Long wave ultraviolet radiation (UVA) has been shown to play an important role in the overall response of skin to solar radiation, including sunburn, tanning, premature aging, and non-melanoma skin cancer. UVA induction of inflammation in human skin is thought to be mediated by membrane lipid derived products. In order to investigate the mechanism of this response we examined the effect of UVA on phospholipid metabolism of human epidermal keratinocytes in culture. Keratinocytes were grown in serum free low calcium medium. The cells were prelabeled with [3H] arachidonic acid or [3H] choline and irradiated with UVA (Honle 2002-Hg vapor lamp). Identification and quantitation of specific membrane phospholipid-derived components was achieved using high-performance liquid chromatography, paper chromatography, and radioimmunoassay. UVA resulted in a linear dose dependent release of [3H] arachidonic acid into medium between 1 and 20 joule/cm2. This response was inhibited in an oxygen-reduced environment. The radiolabel released was predominantly free arachidonate and cyclooxygenase metabolites. Cyclooxygenase metabolites prostaglandin E2 and prostacyclin derivative, 6-keto-prostaglandin F1a, were stimulated following UVA irradiation, but the lipoxygenase metabolite, leukotriene B was not detected. Maximal release was measured immediately after irradiation and changed little over 24 h post-irradiation. UVA stimulated an increase of [3H] choline metabolites glycerophosphorylcholine and phosphorylcholine in media extracts suggesting UVA activation of phospholipase C and phospholipase A2 or diacylglyceride lipase

  12. The lethal effect of longwave ultraviolet light and PUVA. An analysis based upon human mesenchymal cells in vitro

    International Nuclear Information System (INIS)

    Jongh, G. de; Bergers, M.; Boezeman, J.B.M.; Verhagen, A.R.; Mier, P.D.

    1984-01-01

    The lethal effect of UVA and PUVA radiation was studied in cultures of fresh and mature monocytes. UVA radiation alone was shown to possess a lethal effect at doses which are attained in the dermis in vivo. The synergistic action of 8-methoxypsoralen and UVA radiation predominated in PUVA radiation, but again a residual effect of UVA alone was demonstrated mathematically. Mature cells were less sensitive than fresh monocytes. The results indicate that a monolayer culture of non-dividing, mesenchymal cells offers considerable advantages over in vivo systems as a model for the study of phototoxicity. (author)

  13. Mechanisms involved in repairing the lesions induced in pBR 322 by PUVA treatment (8-Methoxypsoralen + ultraviolet A light)

    International Nuclear Information System (INIS)

    Bauluz, C.

    1988-01-01

    This work deals with the genotoxic effects derived from damaging pBR322 DNA through PUVA treatment (8-Methoxypsoralen plusUVA light), both with respect to the lethality and mutagenicity of the lesions produced by the treatment. The mechanisms involved in the repair of the plasmid lesions have been investigated by transforming several strains of E. coli differing in their DNA-repair capacities. The frequency, distribution and type of mutations occurring in a restriction fragment of the damaged plasmid were determined in order to establish the mutagenic features of the PUVA treatment. Damages produced bY PUVA habe a strong lethal effect on plasmid survival; however, partial recovery is possible through some of the bacterial DNA repair pathways, namely Excision repair, SOS-repair and a third mechanism which appears to be independent from the analised genes and is detected at high density of lesions per plasmid molecule. PUVA treatment produces a high increase in plasmid mutagenesis; however, the contribution of such an increase to the whole plasmid survival is negligible. Only punctual mutations were detected and consisted mainly in base-pair substitutions. Some mutation-prone regions were sound inside the investigated DNA fragment, a though their existence is more likely to be related with the structure acquired by the damaged DNA than with the type of damaging agent. (Author)

  14. PUVA combination therapy.

    Science.gov (United States)

    Morison, W L

    1985-08-01

    Various adjunctive treatments are now frequently used in combination with PUVA therapy with the aims of limiting adverse effects, improving efficacy and decreasing the cost of treatment. In the management of psoriasis, PUVA plus retinoids, PUVA plus methotrexate and PUVA plus UVB phototherapy are the most frequently used combinations. PUVA plus topical corticosteroids and PUVA plus anthralin are also efficacious but adverse effects and poor acceptance by patients are limiting factors. Combinations of PUVA plus nitrogen mustard and ionizing radiation are used in mycosis fungoides to treat tumors and residual disease in secluded sites. In the management of photodermatoses with PUVA therapy, prednisone is often required to prevent exacerbation of disease. A combination of prednisone and PUVA therapy can also be useful in lichen planus and atopic eczema. The selection of a suitable combination treatment, will depend upon the preferences of the clinician, the disease being treated, and the characteristics of the patient.

  15. Effect of long-wave ultraviolet light on the lens. I. Model systems for detecting and measuring effect on the lens in vitro

    International Nuclear Information System (INIS)

    Kuck, J.F.R. Jr.

    1976-01-01

    Rat, mouse, and chick lenses incubated with 3-aminotriazole under long-wave ultraviolet (UV) show reduced accumulation and incorporation of leucine and a loss of glutathione. The effect on leucine incorporation is strikingly enhanced when capsule-epithelium pools are incubated. The procedure may identify photosensitizers or metabolic inhibitors which are cataractogenic when acting in conjunction with UV

  16. Are stress proteins induced during PUVA therapy?

    Energy Technology Data Exchange (ETDEWEB)

    Al-Masaud, A.S. [Leeds Univ. (United Kingdom); Cunliffe, W.J.; Holland, D.B. [Leeds General Infirmary (United Kingdom)

    1996-05-01

    Heat shock or stress proteins are produced in practically all cell types when they are exposed to temperatures a few degrees above normal. Measurement of the skin temperature of patients undergoing psoralen and ultraviolet A (PUVA) cabinet treatment for psoriasis revealed that the outer layers of the skin experience a mean temperature rise of 5.3{sup o}C. However, this did not produce a detectable stress response in epidermal samples taken after PUVA treatment. In vitro exposure of epidermis from biopsies or of cultured keratinocytes to a 5-7{sup o}C temperature rise produced a heat shock response, as measured by an increase in the production of proteins of the HSP90 and HSP70 families. These results were confirmed by the use of specific monoclonal antibodies. The corresponding mRNAs were also analysed using labelled probes. In an in vitro system, following simulated PUVA treatment of cultured keratinocytes, increases in the synthesis of HSP90 and HSP70 were detected but these increases did not correlate with changes in mRNA levels. (author).

  17. Are stress proteins induced during PUVA therapy?

    International Nuclear Information System (INIS)

    Al-Masaud, A.S.; Cunliffe, W.J.; Holland, D.B.

    1996-01-01

    Heat shock or stress proteins are produced in practically all cell types when they are exposed to temperatures a few degrees above normal. Measurement of the skin temperature of patients undergoing psoralen and ultraviolet A (PUVA) cabinet treatment for psoriasis revealed that the outer layers of the skin experience a mean temperature rise of 5.3 o C. However, this did not produce a detectable stress response in epidermal samples taken after PUVA treatment. In vitro exposure of epidermis from biopsies or of cultured keratinocytes to a 5-7 o C temperature rise produced a heat shock response, as measured by an increase in the production of proteins of the HSP90 and HSP70 families. These results were confirmed by the use of specific monoclonal antibodies. The corresponding mRNAs were also analysed using labelled probes. In an in vitro system, following simulated PUVA treatment of cultured keratinocytes, increases in the synthesis of HSP90 and HSP70 were detected but these increases did not correlate with changes in mRNA levels. (author)

  18. Cell cycle analysis of cultured mammalian cells after exposure to 4,5',8-trimethylpsoralen and long-wave ultraviolet light

    International Nuclear Information System (INIS)

    Cohen, S.R.; Burkholder, D.E.; Varga, J.M.; Carter, D.M.; Bartholomew, J.C.

    1981-01-01

    Cell cycle analysis was used to study the the effect of 4,5'8-trimethylpsoralen (TMP) and long-wave ultraviolet light (UV-A) on cultured mammalian cells. DNA distribution patterns were measured for murine melanoma cells (a cloned line of Cloudman S91) and a strain of diploid human skin fibroblasts (CRL 1295) using both a microfluorimetry procedure and flow cytometry. The untreated cells and those receiving TMP along and UV-A alone had identical DNA content as assessed at several posttreatment intervals (0-72 hr). The majority of cells in control groups contained a G1 DNA content, whereas exposure to TMP (2 x 10(-7) M) plus UV-A (1 Joule/cm2) led to the accumulation of cells in the G2 phase. These observations were similar for each cell type and both analytical techniques were in excellent agreement. The finding that psoralen plus UV-A induces a phase-specific G2 blockade in cultured cells has important implications for understanding the mechanisms which account for enhanced pigmentation and suppression of cellular proliferation following exposure to these agents in vivo

  19. Studies on cutaneous lipid peroxide with special reference to the influences of ultraviolet irradiation

    International Nuclear Information System (INIS)

    Nomura, Kazuo

    1981-01-01

    The purpose of this study was to investigate the participation of lipid peroxide (LP) in some skin damages due to ultraviolet (UV) irradiation. Results obtained were as follows. 1) Long wave UV (UVA) was irradiated to rat skin homogenates. The levels of LP increased linearly with irradiation time. 2) When 8-methoxypsoralen was added to the homogenates prior to UVA irradiation, however, the LP levels showed no increase. 3) Various anti-oxidative agents were added to homogenates and UVA was irradiated. Only Vit. E reduced the LP levels in proportion to its concentrations. 4) Anti-oxidative agents were given to rats which were then exposed to PUVA (8-methoxypsoralen plus UVA) treatment. Among them, administration of Vit. E and pantethine was associated with reduction of serum and cutaneous LP levels with only slight histologic changes in the involved skin. 5) Vit. E deficient rats were treated with PUVA. In these models, cutaneous LP levels raised from 24 hours to 96 hours after PUVA treatment and histologic changes such as vacuolization, blister formation and cell degeneration were remarkable. From the above data, it became evident that lipid peroxidation took place in skin tissue per se and even in the UVA wave length region. After PUVA treatment, cutaneous LP levels relatively well correlated with histologic changes of the involved skin. The results suggested that LP played a certain role in skin damages due to UV. (author)

  20. Comparative evaluation of NBUVB phototherapy and PUVA photochemotherapy in chronic plaque psoriasis

    Directory of Open Access Journals (Sweden)

    Dayal Surabhi

    2010-01-01

    Full Text Available Background: Psoralen UV-A (PUVA is an established therapy for psoriasis, but there is a well-documenated risk of melanoma and nonmelanoma skin cancer. Narrow-band Ultraviolet-B (NBUVB therapy has a lower carcinogenic risk, has equal therapeutic potential and is considerably safe in the long term than PUVA. Aim: The aim of present study was to compare the efficacy and side-effects of PUVA and NBUVB in chronic plaque psoriasis. Methods: Sixty patients of chronic plaque psoriasis were taken up for the study and were randomly divided into two groups of 30 each. They were well matched in terms of age, sex, psoriasis extent and pretreatment psoriasis area severity index (PASI scoring. One group was treated with twice-weekly narrow-band UV-B (TL-01 phototherapy and the other group received twice-weekly oral 8-Methoxsalen PUVA for a period of 3 months. Results: Both the groups achieved >75% reduction in the PASI score or complete clearance at the end of 3 months, but PUVA group patients required significantly fewer number of treatment sessions and fewer number of days to clear the psoriasis as compared to the NBUVB group, while the mean cumulative clearance dose and adverse effects were significantly lower in the NBUVB group. Conclusion: We concluded that PUVA group patients achieved a faster clearance, but the adverse effects were significantly lower in the NBUVB group.

  1. Photochemotherapy - psoralens + UV-A(PUVA) - does it increase the risk for cancer. Fotokjemoterapi - psoralen + UV-A(PUVA) - oeket risiko for kreft

    Energy Technology Data Exchange (ETDEWEB)

    Harnes, D K; Thune, P [Ullevaal Hospital, Oslo (Norway)

    1993-01-01

    Photochemotherapy with psoralens + ultraviolet (UV)-A light (PUVA) has been used for about 16 years to treat psoriasis. Some reports have indicated a higher frequency of cutaneous squamous cell carcinoma among treated patients. The results are not consistent, however, and are not generally conceded. The material from Ullevaal Hospital comprises 585 patients who have been treated with PUVA from 1977 to 1991. Three patients developed cutaneous squamous cell carcinoma, but in one of them the tumour developed before start of PUVA treatment. The two others had received only very small doses. One of them had an intraepithelial cancer of the penis. In addition the authors registered various internal cancers in 25 patients. The Norwegian Cancer Registry compared the patient material with a matched control group as regards sex, age and age-specific incidence rate. There was no statistically significant difference in incidence between the patient and the control group. 15 refs., 1 tab.

  2. Benney's long wave equations

    International Nuclear Information System (INIS)

    Lebedev, D.R.

    1979-01-01

    Benney's equations of motion of incompressible nonviscous fluid with free surface in the approximation of long waves are analyzed. The connection between the Lie algebra of Hamilton plane vector fields and the Benney's momentum equations is shown

  3. Photochemotherapy - psoralens + UV-A(PUVA) - does it increase the risk for cancer?

    International Nuclear Information System (INIS)

    Harnes, D.K.; Thune, P.

    1993-01-01

    Photochemotherapy with psoralens + ultraviolet (UV)-A light (PUVA) has been used for about 16 years to treat psoriasis. Some reports have indicated a higher frequency of cutaneous squamous cell carcinoma among treated patients. The results are not consistent, however, and are not generally conceded. The material from Ullevaal Hospital comprises 585 patients who have been treated with PUVA from 1977 to 1991. Three patients developed cutaneous squamous cell carcinoma, but in one of them the tumour developed before start of PUVA treatment. The two others had received only very small doses. One of them had an intraepithelial cancer of the penis. In addition the authors registered various internal cancers in 25 patients. The Norwegian Cancer Registry compared the patient material with a matched control group as regards sex, age and age-specific incidence rate. There was no statistically significant difference in incidence between the patient and the control group. 15 refs., 1 tab

  4. Photochemical (PUVA) treatment of isolated rat islets

    International Nuclear Information System (INIS)

    Schmidt, S.; Wilke, B.; Kloeting, I.

    1984-01-01

    Isolated rat islets were irradiated with long-wave ultraviolet light alone or in combination with the photosensitizer 8-methoxypsoralen. The influence on specific beta cell functions was determined with the aim to find out experimental conditions which allow the use of such islets for transplantation. Short-term effects: Ultraviolet light affected [ 3 H]leucine incorporation into (pro)insulin (5 J/cm 2 : 53.8 %, 10 J/cm 2 : 41.0 % of the controls) and insulin release was slightly reduced. 8-methoxypsoralen enhanced the irradiation effect. Long-term effects: A restoration of irradiation-affected beta cell function was detected after 5 days of culture unless the dose exceeded 2 J/cm 2 (0.1 μM 8-methoxypsoralen) or 1 J/cm 2 (1 μM 8-methoxypsoralen). After functional restoration islets were used for transplantation experiments. (author)

  5. Photochemical (PUVA) treatment of isolated rat islets

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, S; Wilke, B; Kloeting, I [Zentralinstitut fuer Diabetes, Karlsburg (German Democratic Republic)

    1984-05-01

    Isolated rat islets were irradiated with long-wave ultraviolet light alone or in combination with the photosensitizer 8-methoxypsoralen. The influence on specific beta cell functions was determined with the aim to find out experimental conditions which allow the use of such islets for transplantation. Short-term effects: Ultraviolet light affected (/sup 3/H)leucine incorporation into (pro)insulin (5 J/cm/sup 2/ : 53.8 %, 10 J/cm/sup 2/ : 41.0 % of the controls) and insulin release was slightly reduced. 8-methoxypsoralen enhanced the irradiation effect. Long-term effects: A restoration of irradiation-affected beta cell function was detected after 5 days of culture unless the dose exceeded 2 J/cm/sup 2/ (0.1 ..mu..M 8-methoxypsoralen) or 1 J/cm/sup 2/ (1 ..mu..M 8-methoxypsoralen). After functional restoration islets were used for transplantation experiments.

  6. Small molecular antioxidants effectively protect from PUVA-induced oxidative stress responses underlying fibroblast senescence and photoaging.

    Science.gov (United States)

    Briganti, Stefania; Wlaschek, Meinhard; Hinrichs, Christina; Bellei, Barbara; Flori, Enrica; Treiber, Nicolai; Iben, Sebastian; Picardo, Mauro; Scharffetter-Kochanek, Karin

    2008-09-01

    Exposure of human fibroblasts to 8-methoxypsoralen plus ultraviolet-A irradiation (PUVA) results in stress-induced cellular senescence in fibroblasts. We here studied the role of the antioxidant defense system in the accumulation of reactive oxygen species (ROS) and the effect of the antioxidants alpha-tocopherol, N-acetylcysteine, and alpha-lipoic acid on PUVA-induced cellular senescence. PUVA treatment induced an immediate and increasing generation of intracellular ROS. Supplementation of PUVA-treated fibroblasts with alpha-tocopherol (alpha-Toc), N-acetylcysteine (NAC), or alpha-lipoic acid (alpha-LA) abrogated the increased ROS generation and rescued fibroblasts from the ROS-dependent changes into the cellular senescence phenotype, such as cytoplasmic enlargement, enhanced expression of senescence-associated-beta-galactosidase and matrix-metalloproteinase-1, hallmarks of photoaging and intrinsic aging. PUVA treatment disrupted the integrity of cellular membranes and impaired homeostasis and function of the cellular antioxidant system with a significant decrease in glutathione and hydrogen peroxide-detoxifying enzymes activities. Supplementation with NAC, alpha-LA, and alpha-Toc counteracted these changes. Our data provide causal evidence that (i) oxidative stress due to an imbalance in the overall cellular antioxidant capacity contributes to the induction and maintenance of the PUVA-induced fibroblast senescence and that (ii) low molecular antioxidants protect effectively against these deleterious alterations.

  7. Therapy of psoriasis with retinoid plus PUVA

    International Nuclear Information System (INIS)

    Heidbreder, G.; Christophers, E.

    1979-01-01

    In a group of 40 patients suffering from wide-spread psoriasis oral administration of a retinoid (Ro 10-9359) was followed by PUVA therapy. The clearance rate was increased by 30% as compared to PUVA alone. Except for cheilitis no side effects were seen. Histological analysis in 20 patients before, during and after therapy revealed an intensification of psoriatic tissue changes after retinoid treatment. Loss of corneal layers, massive exoserosis, and neutrophil migration were prominent features. Mitotic counts were not increased by the pretreatment. The increased susceptibility of diseased skin to PUVA as produced by this drug appears to be based on several factors related to the tissue changes revealed by histology. (orig.) [de

  8. Semen analysis under photochemotherapy (PUVA-therapy)

    International Nuclear Information System (INIS)

    Schill, W.B.; Hofmann, C.; Plewig, G.

    1979-01-01

    In 9 male patients with psoriasis vulgaris a semen analysis before and during photochemotherapy with 8-methoxypsoralen and UVA (PUVA) was performed to rule out drug-induced toxic damage of spermatogenesis or impairment of fertility due to scrotal hyperthermia. Two hours after oral application of 40-60 mg 8-methoxypsoralen the patients had been irradiated in UVA high intensity treatment units. PUVA-treatments were performed four times weekly until total body clearing was achieved. For complete remission 13-26 (mean 20.5) PUVA-treatments were necessary. Corresponding total UVA-doses were 35.3 - 191.0 (mean 83.2) Joule/cm 2 . The investigated parameters total motility, progressive motility, spermatozoa density, total spermatozoa count, spermatozoa morphology, and seminal plasma fructose remained unchanged. Only the volume of the ejaculate showed a small decrease during 3 months of therapy. From this pilot study there is no evidence, that PUVA-therapy leads to an impairment of fertility in male patients within their reproductive age. (orig.) [de

  9. Effect of 8-methoxypsoralen-plus ultraviolet light on cell-virus interaction: the transforming infection; effect of PUVA on the transformation of baby hamster kidney cells by polyma virus

    International Nuclear Information System (INIS)

    Morhenn, V.B.; Kaye, J.A.

    1979-01-01

    Pre-treatment of baby hamster kidney (BHK) cells with 8-methoxypsoralen (8-MOP) plus ultraviolet (UV) light enhances the frequency of their transformation by polyoma (Py) virus. Of the doses tested, 0.5 microgram/m1 8-MOP plus 0 . 3 J/cm2 UV-light results in maximal (30-fold) stimulation of viral transformation. 8-MOP alone does not affect viral transformation and UV-light alone causes only a slight increase in the transformation frequency. Thus the drug and light act synergistically in promoting the effect. Treatment of BHK cells with drug plus light without Py infection does not lead to a transformed morphology. A drug-light combination (0 . 01 microgram/m1 8-MOP plus 1 . 2 J/cm2 UV) that inhibits cellular DNA synthesis is 75% of control at 28 hr after treatment results in a 6-fold stimulation of the transformation frequency

  10. Sensitivity of Escherichia coli acrA Mutants to Psoralen plus Near-Ultraviolet Radiation

    DEFF Research Database (Denmark)

    Hansen, M. Trier

    1982-01-01

    The sensitivity to psoralen plus near-ultraviolet radiation (PUVA) was compared in a pair of E. coli strains differing at the acrA locus. Survival was determined for both bacteria and phage λ. AcrA mutant cells were 40 times more sensitive than wild type to the lethal effect of PUVA. Free λ phage...

  11. Cutaneous neoplasia following PUVA therapy for psoriasis

    Energy Technology Data Exchange (ETDEWEB)

    McKenna, K.E.; Handley, J.; McGinn, S.; Allen, G. [Belfast City Hospital (United Kingdom). Dept. of Dermatology; Patterson, C.C. [Queen`s Univ., Belfast, Northern Ireland (United Kingdom)

    1996-04-01

    To determine the risk of cutaneous neoplasia following photochemotherapy (PUVA), we reviewed patients with psoriasis treated at out unit between 1979 and 1991. Two hundred and forty-five patients were assessed, with a median duration of follow-up of 9.5 years. Fifty-nine per cent were male, and 41% female. The median number of exposures was 59, and the median total dose was 133J/cm{sup 2} for the group as a whole. Non-melanoma skin cancers (NMSC) occurred in six individuals (2.4%), basal cell carcinoma occurred in all six and one individual also developed four squamous cell carcinomas and Bowen`s disease of the penis. No cases of malignant melanoma were recorded. Patients who developed NMSC received a median number of 225 exposures and a median cumulative dose of 654J/cm{sup 2}. Compared with a control study population in West Glamorgan, Wales, there was a 1.4 (95% confidence limits (CL) 0.5 and 3.1) times increased risk of NMSC. A statistically significant increased incidence of NMSC was found for patients who had received 100 or more exposures, and 250 or more J/cm{sup 2}, with risks of 3.7 (95% CL 1.0 and 9.5), and 4.0 (95% CL 1.1 and 10), respectively. A PUVA dose of < 250 J/cm{sup 2} or < 100 exposures conferred a minimal increase in risk of NMSC in our study population. (author).

  12. Erythemal and therapeutic response of psoriasis to PUVA using high-dose UVA

    International Nuclear Information System (INIS)

    Speight, E.L.; Farr, P.M.

    1994-01-01

    In PUVA treatment of psoriasis, clinical observation suggests that uninvolved skin is more susceptible to PUVA erythema than lesions of psoriasis. If this is the case, then the efficacy of PUVA treatment might be increased by using localized high-dose UVA restricted to lesional skin. We have therefore studied the erythemal and therapeutic response of psoriasis to PUVA using high-dose UVA and, for comparison, the erythemal response to UVB. This study demonstrates that psoriasis may clear rapidly, without burning, using high-dose UVA. Availability of a suitable irradiation apparatus would allow rapid and effective PUVA treatment to be used for localized, resistant disease. (author)

  13. Mechanisms of PUVA (Psoralen + UVA) photochemotherapy

    International Nuclear Information System (INIS)

    Zarebska, Z.; Waszkowska, E.; Barszcz, D.

    1998-01-01

    Our studies are aimed at understanding the action of PUVA phototherapy on the lymphocytes membrane. The investigations are carried out on the model lecithins having in the second position oleic/linoleic acid as the majority of lecithins have. Previous investigations led to a discovery of a new class of photoadducts which accompany the photolytic breakdown of lecithin. The new photoadducts were obtained by irradiating a mixture of psoralen or 8-methoxypsoralen with p hosphatidylcholine; separated by HPLC or TLC and characterized by UV and NMR spectra and mass spectrometry. Kinetics of psoralen photolysis in the presence of lecithin was followed and the yield of the initial photoproducts was determined. The predominant reaction was a cycloaddition between one of the two photoreactive sites of psoralen (3,4-pyrone edge) and one of the olefinic bonds of the unsaturated fatty acid linked in the second position of the glycerol moiety of phosphatidylcholine. Two adducts were purified to homogeneity and characterized: an adduct of psoralen to oleic acid in lecithin (PCd1pal PSO) and two isomeric adducts to the free linoleic acid (d2 PSO). The extreme sensitivity of isolated photoproducts was encountered in the course of identification analysis (UV, NR and mass spectrometry). This was in contrast to the other stable psoralen cyclobutane adducts, like psoralen thymine or psoralen fatty-acid-methyl-ester. We assume that the short life-time of our adducts is associated with the presence of a -COOH end group in the free fatty acid, and its ester group -COO- in the lecithins. These compounds undergo hydrolysis/oxidation reactions in aqueous micelles and in the slightly hydrated methanol. The photoadducts are also photosensitive, e.g. the cyclobutane ring splits under laser beam (337 nm, 50 mJ) applied in the MALDI (Matrix Assisted Laser Desorption and Ionization) method for molecular mass estimation. With the more gentle method, LSIMS (Liquid Secondary Mass Spectrometry), molar

  14. Plasma levels of 8-methoxypsoralen following PUVA-bath photochemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kobyletzki, G. von; Hoffmann, K.; Kerscher, M.; Altmeyer, P. [Ruhr-Univ., Dept. of Dermatology, Bochum (Germany)

    1998-08-01

    Administration of 8-methoxypsoralen (8-MOP) in a dilute bath water solution is an effective therapeutic alternative to oral PUVA therapy, avoiding systemic side effects, offering better bioavailability of the psoralen and requiring much smaller amounts of UVA for induction of therapeutic effects. To obtain exact data about the percutaneous absorption of 8-MOP during a psoralen bath, the plasma levels of the drug were determined in 26 patients with different skin diseases by a reverse high-performance liquid chromatographic method. Fifteen patients receiving oral PUVA therapy (0.8 mg 8-MOP/kg body weight) served as a positive control group. Bath solutions were prepared by diluting 15 ml of 0.5% stock solution of 8-MOP in 150 l of bath water (0.5 mg/l, 37 deg. C). Blood samples were drawn from patients 5, 30, 60, 120 and 180 min after the bath. In the oral PUVA group, blood samples were obtained 1 1/2 h after administration of the drug. In 23 og 26 patients, 8-MOP levels were undetectable in every blood sample. After 30 min, two patients showed detectable levels of 8-MOP (5 ng/ml, 7 ng/ml), while 60 min after the PUVA bath 8-MOP was detectable in only one volunteer (5 ng/ml). In patients receiving oral 8-MOP therapy, serum levels varied between 45 and 360 ng/ml 1 1/2 h after drug administration. Our data confirm extremely low 8-MOP levels resulting from 8-MOP bath water treatments and provide confirmation of the absence of systemic side effects in patients who are undergoing PUVA-bath therapy. (au) 15 refs.

  15. Plasma levels of 8-methoxypsoralen following PUVA-bath photochemotherapy

    International Nuclear Information System (INIS)

    Kobyletzki, G. von; Hoffmann, K.; Kerscher, M.; Altmeyer, P.

    1998-01-01

    Administration of 8-methoxypsoralen (8-MOP) in a dilute bath water solution is an effective therapeutic alternative to oral PUVA therapy, avoiding systemic side effects, offering better bioavailability of the psoralen and requiring much smaller amounts of UVA for induction of therapeutic effects. To obtain exact data about the percutaneous absorption of 8-MOP during a psoralen bath, the plasma levels of the drug were determined in 26 patients with different skin diseases by a reverse high-performance liquid chromatographic method. Fifteen patients receiving oral PUVA therapy (0.8 mg 8-MOP/kg body weight) served as a positive control group. Bath solutions were prepared by diluting 15 ml of 0.5% stock solution of 8-MOP in 150 l of bath water (0.5 mg/l, 37 deg. C). Blood samples were drawn from patients 5, 30, 60, 120 and 180 min after the bath. In the oral PUVA group, blood samples were obtained 1 1/2 h after administration of the drug. In 23 og 26 patients, 8-MOP levels were undetectable in every blood sample. After 30 min, two patients showed detectable levels of 8-MOP (5 ng/ml, 7 ng/ml), while 60 min after the PUVA bath 8-MOP was detectable in only one volunteer (5 ng/ml). In patients receiving oral 8-MOP therapy, serum levels varied between 45 and 360 ng/ml 1 1/2 h after drug administration. Our data confirm extremely low 8-MOP levels resulting from 8-MOP bath water treatments and provide confirmation of the absence of systemic side effects in patients who are undergoing PUVA-bath therapy. (au)

  16. Enhancement of cutaneous delayed hypersensitivity reactions by a single exposure to UV-A or PUVA

    International Nuclear Information System (INIS)

    Moberg, S.; Mobacken, H.

    1982-01-01

    The influence of irradiation with UV-A and PUVA (8-methoxy-psoralen and UV-A) on delayed hypersensitivity reactions to microbial antigens was studied in healthy human individuals. Skin reactions to Candida albicans antigen and PPD were enhanced by UV-A als well as by PUVA compared with nonirradiated tests. A statistically significant difference was reached with UV-A for both antigens. For PUVA, erythemogenic doses to Candida tests produced a significant increase of response. (orig.)

  17. The contribution of medical physics to the development of psoralen photochemotherapy (PUVA) in the UK: a personal reminiscence

    Energy Technology Data Exchange (ETDEWEB)

    Diffey, Brian [Regional Medical Physics Department, Newcastle General Hospital, Newcastle upon Tyne NE4 6BE (United Kingdom)

    2006-07-07

    Psoralen photochemotherapy (PUVA) is the combined treatment of skin disorders with a photosensitizing drug (Psoralen) and UltraViolet A radiation. The introduction of PUVA therapy has arguably been the most important development in dermatology over the past 30 years and from the first days of the treatment being introduced in the UK, British medical physicists were an integral part of the effort to establish it. Medical physicists have contributed to this development in a number of ways, from designing irradiation units in the early days of the technique, through to collaborating with dermatologists in prosecuting clinical and experimental studies aimed at improving patient outcomes. That the dose of UVA radiation is administered quantitatively, and not qualitatively, has probably been the single most important contribution made by several medical physicists over this period. However, despite concerns that were expressed almost 30 years ago about the accuracy with which UVA doses are administered to patients, the medical physics community still has some way to go before we can be satisfied that statements about UVA irradiance and dose can be made with confidence. (review)

  18. PUVA therapy is preferable to UVB phototherapy in the management of HIV-associated dermatoses

    Energy Technology Data Exchange (ETDEWEB)

    Morison, W.L. [Johns Hopkins Univ., Baltimore, MD (United States)

    1996-08-01

    Both methoxsalen plus UVA (PUVA) therapy and UVB phototherapy are commonly used in the management of human immunodeficiency virus-associated dermatoses but UVB phototherapy appears to be the preferred treatment. There are several considerations, in particular therapeutic efficacy and therapeutic profile, which suggest that PUVA therapy might be more effective. This needs to be established in clinical trials. (Author).

  19. Long wave polar modes in semiconductor heterostructures

    CERN Document Server

    Trallero-Giner, C; García-Moliner, F; Garc A-Moliner, F; Perez-Alvarez, R; Garcia-Moliner, F

    1998-01-01

    Long Wave Polar Modes in Semiconductor Heterostructures is concerned with the study of polar optical modes in semiconductor heterostructures from a phenomenological approach and aims to simplify the model of lattice dynamics calculations. The book provides useful tools for performing calculations relevant to anyone who might be interested in practical applications. The main focus of Long Wave Polar Modes in Semiconductor Heterostructures is planar heterostructures (quantum wells or barriers, superlattices, double barrier structures etc) but there is also discussion on the growing field of quantum wires and dots. Also to allow anyone reading the book to apply the techniques discussed for planar heterostructures, the scope has been widened to include cylindrical and spherical geometries. The book is intended as an introductory text which guides the reader through basic questions and expands to cover state-of-the-art professional topics. The book is relevant to experimentalists wanting an instructive presentatio...

  20. Comparison of clinical and cost-effectiveness of psoralen + ultraviolet A versus psoralen + sunlight in the treatment of chronic plaque psoriasis in a developing economy.

    Science.gov (United States)

    Aggarwal, Komal; Khandpur, Sujay; Khanna, Neena; Sharma, Vinod K; Pandav, Chandrakant S

    2013-04-01

    Psoralen + ultraviolet A (PUVA) therapy is an established modality for psoriasis. As India is a tropical country that has good availability of natural sunlight psoralen + sunlight (PUVAsol) may be a more convenient option. To compare the efficacy and cost-effectiveness of PUVA versus PUVAsol in chronic plaque psoriasis. Cases of chronic plaque psoriasis with body surface area ≥10% or Psoriasis Area and Severity Index (PASI) ≥10, excluding erythrodermic or pustular psoriasis, were randomized to receive either PUVA or PUVAsol, with endpoint being the achievement of PASI 90 or completion of 12 weeks treatment, whichever is earlier. Cost analysis was also undertaken. Thirty-six cases (16 in PUVA and 20 in PUVAsol group) completed treatment. In the PUVA group, 15 cases (93.75%) responded to therapy while in the PUVAsol group, 15 (75%) responded (P = 0.29). Mean baseline PASI in the PUVA and PUVAsol groups was 16 and 14.4, respectively, and at endpoint was 1.62 and 3.77. There was a significantly greater reduction in PASI in the PUVA group at 2 and 4 weeks but at 8 and 12 weeks and endpoint, it was comparable. Treatment failure occurred in 6.25% and 25% of cases respectively (P = 0.29). Side effects were higher with PUVA. Total cost of therapy was significantly higher in the PUVA group (P = 0.002). Cost-effectiveness ratio was US$0.72 with PUVA and US$0.37 with PUVAsol. Both PUVA and PUVAsol were equally efficacious, with PUVAsol being twice as cost effective. Hence, PUVAsol may be recommended as treatment for psoriasis in a developing economy such as India. © 2013 The International Society of Dermatology.

  1. Role of anti-depressant fluoxetine in the puva treatment of psoriasis vulgaris

    Directory of Open Access Journals (Sweden)

    Mitra A

    2001-11-01

    Full Text Available Severity of psoriasis vulgaris is known to be modified by psychological stress. The objective of this study was to evaluate the role of fluoxetine in the PU VA treatment of psoriasis. Twenty patients with progressive disease having more than thirty per cent body area involvement were included in a randomized, double blinded, placebo- controlled, age and sex matched study. All patients were on PUVA treatment, half of patients were given fluoxetine 20 mgs daily whereas the ten were given placebo. Assessment was done by Psoriasis Area and Severity Index (PASI scoring after every 5 exposures of PUVA treatment till 20 treatments. All ten patients who took fluoxetine along with PUVA treatment showed better response and quicker remission. Fluoxetine may be used as an adjuvant in PUVA treatment of psoriasis.

  2. Role of anti-depressant fluoxetine in the puva treatment of psoriasis vulgaris

    Directory of Open Access Journals (Sweden)

    Mitra A

    2003-03-01

    Full Text Available Severity of Psoriasis Vulgaris is known to be modified by psychological stress. The objective of this study was to evaluate the role of Fluoxetine in the PUVA treatment of Psoriasis. Twenty patients with progressive disease having more than thirty per cent body area involvement were included in a randomized, double blinded, placebo-controlled, age and sex matched study. All patients were on PUVAtreatment; half of the patients were given Fluoxetine 20 mgms daily whereas the other ten were given placebo. Assessment was done by Psoriasis Area and Severity Index (PASI scoring after every 5 exposures of PUVA treatment till 20 treatments. All ten patients who took Fluoxetine along with PUVA treatment showed better response and quicker remission. Fluoxetine may be used as an adjuvant in PUVA treatment of Psoriasis.

  3. An observer-blinded randomized controlled pilot trial comparing localized immersion psoralen-ultraviolet A with localized narrowband ultraviolet B for the treatment of palmar hand eczema.

    Science.gov (United States)

    Brass, D; Fouweather, T; Stocken, D D; Macdonald, C; Wilkinson, J; Lloyd, J; Farr, P M; Reynolds, N J; Hampton, P J

    2017-12-13

    Hand eczema is a common inflammatory dermatosis that causes significant patient morbidity. Previous studies comparing psoralen-ultraviolet A (PUVA) with narrowband ultraviolet B (NB-UVB) have been small, nonrandomized and retrospective. To conduct an observer-blinded randomized controlled pilot study using validated scoring criteria to compare immersion PUVA with NB-UVB for the treatment of chronic hand eczema unresponsive to topical steroids. Sixty patients with hand eczema unresponsive to clobetasol propionate 0·05% were randomized to receive either immersion PUVA or NB-UVB twice weekly for 12 weeks with assessments at intervals of 4 weeks. The primary outcome measure was the proportion of patients achieving 'clear' or 'almost clear' Physician's Global Assessment (PGA) response at 12 weeks. Secondary outcome measures included assessment of the modified Total Lesion and Symptom Score (mTLSS) and the Dermatology Life Quality index (DLQI). In both treatment arms, 23 patients completed the 12-week assessment for the primary outcome measure. In the PUVA group, five patients achieved 'clear' and eight 'almost clear' [intention-to-treat (ITT) response rate 43%]. In the NB-UVB group, two achieved 'clear' and five 'almost clear' (ITT response rate 23%). For the secondary outcomes, median mTLSS scores were similar between groups at baseline (PUVA 9·5, NB-UVB 9) and at 12 weeks (PUVA 3, NB-UVB 4). Changes in DLQI were similar, with improvements in both groups. In this randomized pilot trial recruitment was challenging. After randomization, there were acceptable levels of compliance and safety in each treatment schedule, but lower levels of retention. Using validated scoring systems - PGA, mTLSS and DLQI - as measures of treatment response, the trial demonstrated that both PUVA and NB-UVB reduced the severity of chronic palmar hand eczema. © 2017 British Association of Dermatologists.

  4. Long Wave Infrared Cavity Enhanced Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Taubman, Matthew S.; Scott, David C.; Cannon, Bret D.; Myers, Tanya L.; Munley, John T.; Nguyen, Vinh T.; Schultz, John F.

    2005-12-01

    The principal goal of Pacific Northwest National Laboratory's (PNNL's) long wave infrared (LWIR) cavity enhanced sensor (CES) task is to explore ultra-sensitive spectroscopic chemical sensing techniques and apply them to detecting proliferation of weapons of mass destruction (WMD). Our primary application is detecting signatures of WMD production, but LWIR CES techniques are also capable of detecting chemical weapons. The LWIR CES task is concerned exclusively with developing novel point sensors; stand-off detection is addressed by other PNNL tasks and projects. PNNL's LWIR CES research is distinguished from that done by others by the use quantum cascade lasers (QCLs) as the light source. QCLs are novel devices, and a significant fraction of our research has been devoted to developing the procedures and hardware required to implement them most effectively for chemical sensing. This report details the progress we have made on LWIR CES sensor development.

  5. A comparison of twice-weekly MPD-PUVA and three times-weekly skin typing-PUVA regimens for the treatment of psoriasis

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, D.A.; Rogers, S. [City of Dublin Skin and Cancer Hospital, Dublin (Ireland); Healy, E. [Royal Victoria Infirmary, Newcastle upon Tyne (United Kingdom)

    1995-09-01

    The most frequent PUVA treatment regimen in current use is three times weekly, using skin typing to estimate the starting dose. Recently, it was suggested that twice-weekly treatment, using the minimal phototoxic dose- (MPD) to calculate suberythmal starting doses of UVA, achieved similar clearance rates with fewer treatments and a lower cumulative UVA dose. We have carried out a trial on 83 patients, comparing twice-weekly MPD-PUVA with three times-weekly skin typing-PUVA, in order to test this hypothesis. Although clearance rates were comparable between the two regimens, there was no overall significant difference in the number of treatments or in the cumulative UVA doses at clearance. However, for patients with skin types I and II the cumulative UVA dose was significantly higher using the twice-weekly MPD regimen (70.OJ/cm{sup 2} vs. 55.8J/cm{sup 2}; P<0.05). Our results do not confirm that there is a reduction in cumulative UVA dosage with twice-weekly MPD-PUVA. (Author).

  6. General characteristics of long waves around the South African Coast

    CSIR Research Space (South Africa)

    Rossouw, M

    2013-09-01

    Full Text Available Long-period waves are almost invisible waves due to the long wave-lengths of several hundreds of metres and heights of only decimetres. The effect of these long waves can, however, be devastating in the form of harbour basin oscillations...

  7. PUVA treatment of alopecia areata partialis, totalis and universalis: audit of 10 years' experience at St John's Institute of Dermatology

    International Nuclear Information System (INIS)

    Taylor, C.R.; Hawk, J.L.M.

    1995-01-01

    Our 10-year experience with PUVA treatment for alopecia areata, partialis, totalis and universalis was retrospectively reviewed using charts and follow-up questionnaires for 70 patients at St John's Institute of Dermatology. In all cases, several previous therapies were judged to be unsatisfactory prior to starting PUVA, and many cases were already deemed clinically refractory prior to referral for PUVA. If cases of vellus hair growth are excluded, and those who lost their PUVA-induced regrowth rapidly on follow-up, the effective success rate was at best 6.3% for alopecia areata partialis, 12.5% for alopecia areata totalis and 13.3% for alopecia areata universalis. We affirm that PUVA is generally not an effective treatment for alopecia areata. (Author)

  8. Ultraviolet and visible light penetration of epidermis

    International Nuclear Information System (INIS)

    Eggset, G.; Kavli, G.; Volden, G.; Krokan, H.

    1984-01-01

    Light penetration in untanned skin and skin tanned with UVB (middlewave ultraviolet light) or PUVA (Psoralen photochemotherapy) was compared. Transmission at different wavelengths was measured through sheets of intact epidermis isolated by a suction blister technique. Thick epidermis was collected from a newly formed palmar friction bulla. For these studies a monochromator was used and the range of wavelengths examined was 280-700 nm. The transmission was considerably lower in tanned skin and the difference was most pronounced in the UV range. In the UVB range (290-320 nm), transmission was 13-43% for untanned epidermis, 8-12% for UVB tanned and slightly lower for PUVA tanned epidermis. At wavelengths below 325 nm only a few per cent of light penetrate through thick palmar epidermis. Both UVB and PUVA induce increased melanin content and thickening of the epidermis. Our results indicate that melanin is the most efficient protection against UVA while thickening of epidermis may be as important as the increased melanin content for the protection of living basal cells against the harmful UVB rays. (Auth)

  9. PUVA and methotrexate therapy of psoriasis: how closely do dermatology departments follow treatment guidelines? Psoriasis Audit Workgroup of the British Association of Dermatologists.

    Science.gov (United States)

    Bilsland, D J; Rhodes, L E; Zaki, I; Wilkinson, S M; McKenna, K E; Handfield-Jones, S E; Williams, R E

    1994-08-01

    Following publication of treatment guidelines for patients with psoriasis, a six-centre audit was undertaken to assess current therapeutic practice for two second-line treatments, PUVA and methotrexate. The audit consisted of random sampling of casenotes by external auditors from a paired dermatology department, and assessment by questionnaire. One hundred and eight PUVA and 118 methotrexate casenotes were audited. The commonest indications for treatment were: (a) failure of tropical therapy--PUVA (mean 81% of casenotes), methotrexate (84%); (b) repeated hospital admissions--PUVA (16%), methotrexate (25%). For both PUVA and methotrexate, some aspects of treatment were well documented: PUVA--psoralen dosage (91%), response to PUVA (89%), cumulative lifetime UVA dosage (81%); methotrexate--pretreatment assessment of full blood count (91%), urea and electrolytes (85%), liver function tests (84%). For other aspects documentation was less complete: PUVA--no documentation of presence/absence of skin cancer history (66%), note of photoactive drugs (32%); methotrexate--concurrent medication (69%), history of presence/absence of liver disease (36%). Another aspect which was poorly documented in both PUVA and methotrexate notes was whether advice on contraception/fertility had been given. There was no indication in 29 of 32 casenotes of females of child-bearing age receiving PUVA, and 52 of 63 case notes of relevant patients on methotrexate. This project has demonstrated that formal, multicentre audit based on published guidelines is a practical proposition.

  10. An objective assessment of melanin in vitiligo skin treated with Balneo PUVA therapy.

    Science.gov (United States)

    Hegyi, V; Petrovajová, M; Novotný, M

    2014-02-01

    Visual clinical methods of skin color evaluation for diagnostic purposes are so far mostly subjective and thus inaccurate. We present a modified method of melanin amount measurement based on diffuse reflectance spectroscopy (DRS). This method is non-invasive and objective, and allows easy quantification and comparison of melanin levels. Skin pigmentation was measured by DRS method in 0-18 year old patients at the Department of Pediatric Dermatovenerology, School of Medicine Comenius University Bratislava. Patients were treated for their vitiligo by Balneo PUVA treatment twice weekly. Each patient had measured his remittance spectra from the treated vitiliginous skin before the treatment was started, after 10 irradiations of Balneo PUVA and at the end of the treatment after 25 irradiations of Balneo PUVA. In our study as a reference skin for spectroscopic assessment of melanin in vivo was used the averaged remittance spectra (measured on the inner arm) from the sample of 10 albino patients. The remittance spectra obtained from the vitiligo patients were ratioed against the newly described remittance reference albino skin. We exploited the linear behavior of the spectral curve in the 620-720 nm interval (significant for melanin absorption) and used the slope of the regression line to compute the quantification index α. By clinical examination before the Balneo PUVA therapy, after the 10th dose of Balneo PUVA therapy as well as at the end of the complete course of Balneo PUVA therapy (after 25 irradiations) we recorded a marked increase of pigmentation in all treated patients for their vitiligo. In each patient the values of melanin quantification angle α were calculated. Statistically we found a significant difference between the melanin quantification angle α in vitiliginous skin before, during the 10th dose of treatment and after the treatment. Similar significant difference was also observed between treated and non-involved skin. We could confirm a clear

  11. Maintenance phase in psoralen-ultraviolet A phototherapy of early-stage mycosis fungoides. A critically appraised topic.

    Science.gov (United States)

    Grandi, V; Delfino, C; Pileri, A; Pimpinelli, N

    2017-08-01

    A 65-year-old patient affected by mycosis fungoides (MF) stage IB achieved complete remission (CR) after a cycle of PUVA phototherapy. The U.S. Cutaneous Lymphoma Consortium (USCLC) guidelines suggest that the patient should be kept in the maintenance phase, defined as a 'period of gradual decrease of frequency of UVL [ultraviolet light] while in clinical remission before discontinuation of phototherapy' by slowly tapering the number of psoralen-ultraviolet A (PUVA) applications over time up to clinical relapse. The USCLC guidelines also suggest a standardized schedule for the maintenance phase. Alternatively, the patient could end PUVA therapy and go straight to follow-up. The aim of this critically appraised topic (CAT) was to determine if a maintenance phase gives a significant benefit in terms of relapse rate (RR) and RFI in patients affected by early-stage MF who had achieved CR under PUVA phototherapy. Embase, PubMed and TRIP databases were searched for 'mycosis fungoides' AND [('photochemotherapy' OR 'puva') OR 'psoralen'] in June 2016. Three articles matched our inclusion criteria and are discussed in this CAT. In this field of research the literature is poor and the reported level of evidence is low. Only one of the studies was conducted prospectively, and none were randomized. No significant difference in terms of reduction in relapse rate or increase in RFI in patients who underwent a PUVA maintenance phase emerged when compared with those who went for simple follow-up. Further randomized clinical trials (RCTs) are required in order to evaluate maintenance phase vs. no treatment before it can be favoured as the standard protocol of treatment in early-stage MF. At the time of writing this paper, we report an ongoing Austrian multicentre RCT (Clinical Trial.gov identifier: NCT01686594) that will hopefully give useful results in this topic. © 2017 British Association of Dermatologists.

  12. Effects of water temperature on photosensitization in bath-PUVA therapy with 8-methoxypsoralen

    Energy Technology Data Exchange (ETDEWEB)

    Gruss, C.; Kobyletzki, G. von; Reuther, T.; Husebo, L.; Altmeyer, P. [Ruhr-Univ. of Bochum, Bochum (Germany); Behrens, S.; Kerscher, M. [Univ. of Ulm, Dept. of Dermatology, Ulm (Germany)

    1998-10-01

    The pharmacokinetic aspects of bath-PUVA are not completely clarified. Therefore, we determined the phototoxic response of human skin following psoralen baths at temperatures ranging from 32 deg. C to 42 deg. C (71.6-107.6 deg. F) and UVA doses ranging from 0.5 to 5.5 J/cm{sup 2}. The highest therapeutical photosensitization (i.e. lowest minimal phototoxic dose) was assessed at temperatures of 37 deg. C (98.6 deg. F) and above. Photosensitization was significantly decreased at lower temperatures. These data indicate that a bath temperature of 37 deg. C (98.6 deg. F) should be used to gain optimal therapeutic efficiency in a clinical setting. Furthermore, in order to minimize the risk of adverse phototoxic effects in bath-PUVA, it is important to use a constant temperature during the psoralen bath. (au) 13 refs.

  13. Effects of water temperature on photosensitization in bath-PUVA therapy with 8-methoxypsoralen

    International Nuclear Information System (INIS)

    Gruss, C.; Kobyletzki, G. von; Reuther, T.; Husebo, L.; Altmeyer, P.; Behrens, S.; Kerscher, M.

    1998-01-01

    The pharmacokinetic aspects of bath-PUVA are not completely clarified. Therefore, we determined the phototoxic response of human skin following psoralen baths at temperatures ranging from 32 deg. C to 42 deg. C (71.6-107.6 deg. F) and UVA doses ranging from 0.5 to 5.5 J/cm 2 . The highest therapeutical photosensitization (i.e. lowest minimal phototoxic dose) was assessed at temperatures of 37 deg. C (98.6 deg. F) and above. Photosensitization was significantly decreased at lower temperatures. These data indicate that a bath temperature of 37 deg. C (98.6 deg. F) should be used to gain optimal therapeutic efficiency in a clinical setting. Furthermore, in order to minimize the risk of adverse phototoxic effects in bath-PUVA, it is important to use a constant temperature during the psoralen bath. (au)

  14. Asymptotic approach for the nonlinear equatorial long wave interactions

    International Nuclear Information System (INIS)

    Ramirez Gutierrez, Enver; Silva Dias, Pedro L; Raupp, Carlos

    2011-01-01

    In the present work we use an asymptotic approach to obtain the long wave equations. The shallow water equation is put as a function of an external parameter that is a measure of both the spatial scales anisotropy and the fast to slow time ratio. The values given to the external parameters are consistent with those computed using typical values of the perturbations in tropical dynamics. Asymptotically, the model converge toward the long wave model. Thus, it is possible to go toward the long wave approximation through intermediate realizable states. With this approach, the resonant nonlinear wave interactions are studied. To simplify, the reduced dynamics of a single resonant triad is used for some selected equatorial trios. It was verified by both theoretical and numerical results that the nonlinear energy exchange period increases smoothly as we move toward the long wave approach. The magnitude of the energy exchanges is also modified, but in this case depends on the particular triad used and also on the initial energy partition among the triad components. Some implications of the results for the tropical dynamics are discussed. In particular, we discuss the implications of the results for El Nino and the Madden-Julian in connection with other scales of time and spatial variability.

  15. Influence of PUVA and UVB radiation on delayed hypersensitivity in the guinea pig

    International Nuclear Information System (INIS)

    Morison, W.L.; Parrish, J.A.; Woehler, M.E.; Krugler, J.I.; Bloch, K.J.

    1981-01-01

    Exposure of guinea pigs to UVA (320--400 nm) radiation following administration of 8-methoxypsoralen by gavage (referred to by the acronym, PUVA) or exposure to UVB (290--320 nm) radiation, produced suppression of the cutaneous delayed hypersensitivity reaction at the site of exposure to radiation and at distant nonexposed sites. In these experiments, the animals were immunized by injection of dinitrophenyl-bovine gamma-globulin (DNP-BGG) in complete Freund's adjuvant and delayed hypersensitivity responses were provoked by intradermal injections of DNP-BGG, DNP and BGG on the flanks. Exposure to erythemogenic doses of either PUVA or UVB radiation for 7 days prior to immunization and for the 7 days between immunization and challenge (total period of radiation: 14 days) produced inhibiton of responses to each of the test substances. In addition, treatment with erythemogenic doses of PUVA either for 7 days prior to immunization or during the interval between immunization and challenge with DNP-BGG, inhibited the delayed hypersensitivity responses at the site of irradiation and at a nonexposed site. These findings suggest that in vivo exposure to nonionizing radiation leads to both local and systemic alteration of certain immune responses

  16. Extended Long Wave Hindcast inside Port Solutions to Minimize Resonance

    Directory of Open Access Journals (Sweden)

    Gabriel Diaz-Hernandez

    2016-02-01

    Full Text Available The present study shows a methodology to carry out a comprehensive study of port agitation and resonance analysis in Geraldton Harbor (Western Australia. The methodology described and applied here extends the short and long wave hindcast outside the harbor and towards the main basin. To perform such an analysis, and as the first stage of the methodology, it is necessary to determine, in detail, both the long and short wave characteristics, through a comprehensive methodology to obtain and to hindcast the full spectral data (short waves + long waves, for frequencies between 0.005 and 1 Hz. Twelve-year spectral hindcast wave data, at a location before the reef, have been modified analytically to include the energy input associated with infragravity waves. A decomposition technique based on the energy balance of the radiation stress of short waves is followed. Predictions for long wave heights and periods at different harbor locations are predicted and validated with data recorded during 2004 to 2009. This new database will ensure an accurate and reliable assessment of long wave hourly data (height, period and currents in any area within the main basin of the Port of Geraldton, for its present geometry. With this information, two main task will be completed: (1 undertake a forensic diagnosis of the present response of the harbor, identifying those forcing characteristics related to inoperability events; and (2 propose any layout solutions to minimize, change, dissipate/fade/vanish or positively modify the effects of long waves in the harbor, proposing different harbor geometry modifications. The goal is to identify all possible combinations of solutions that would minimize the current inoperability in the harbor. Different pre-designs are assessed in this preliminary study in order to exemplify the potential of the methodology.

  17. 8-methoxypsoralen and ultraviolet A radiation activate the human elastin promoter in transgenic mice: in vivo and in vitro evidence for gene induction

    International Nuclear Information System (INIS)

    Bernstein, E.F.; Brown, D.B.; Takeuchi, Tsunemichi; Kong, S.K.; Uitto, Jouni; Gasparro, F.P.

    1996-01-01

    Treatment of skin diseases with the combination of 8-methoxypsoralen and ultraviolet A radiation (PUVA) results in clinical alterations in treated skin that resemble those observed in chronically photodamaged skin. The PUVA-treated patients develop nonmelanoma skin cancers, pigmentary alterations and wrinkling characteristic of sun-induced changes. The major alteration in the dermis of sun-damaged skin is the deposition of abnormal elastic fibers, termed solar elastosis. Up-regulation of elastin promoter activity in dermal fibroblasts explains the excess elastic tissue but not the reason for the aberrant morphology of the elastotic material. In order to study photoaging in an experimental system we utilized a transgenic mouse line that expresses the human elastin promoter/chloramphenicol acetyltransferase construct in a tissue-specific and developmentally regulated manner. Although UVB radiation has been demonstrated to increase promoter activity in vitro, UVA fails to demonstrate a similar effect at the doses utilized. In this study, we demonstrate the ability of PUVA treatment to up regulate elastin promoter activity both in vitro and in vivo. These data help to explain the development of photoaging in sun-protected PUVA-treated skin. We attribute the up-regulation of elastin promoter activity in response to PUVA to the formation of DNA photoadducts, which do not occur in response to UVA radiation alone. (UK)

  18. Acute skin lesions following psoralen plus ultraviolet A radiation investigated by optical coherence tomography

    International Nuclear Information System (INIS)

    Liu, Z M; Zhong, H Q; Zhai, J; Wang, C X; Xiong, H L; Guo, Z Y

    2013-01-01

    Psoralen plus ultraviolet A radiation (PUVA) therapy is a very important clinical treatment of skin diseases such as vitiligo and psoriasis, but associated with an increased risk of skin photodamage, especially photoaging. In this work, optical coherence tomography (OCT), a novel non-invasive imaging technology, was introduced to investigate in vivo the photodamage induced by PUVA qualitatively and quantitatively. Balb/c mouse dorsal skin was treated with 8-methoxypsoralen (8-MOP), and then exposed to UVA radiation. OCT images of the tissues were obtained by an OCT system with a 1310 nm central wavelength. Skin thickness and the attenuation coefficient were extracted from the OCT images to analyze the degree of injury to mouse skin. The results demonstrated that PUVA-treated skin showed an increase in skin thickness, and a reduction of attenuation coefficient in the OCT signal compared with the control groups. The data also showed good correlation with the results observed in histological sections using hematoxylin and eosin staining. In conclusion, OCT is a promising tool for photobiological studies aimed at assessing the effect of PUVA therapy in vivo. (paper)

  19. PUVA treatment of alopecia areata partialis, totalis and universalis: audit of 10 years` experience at St John`s Institute of Dermatology

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, C.R.; Hawk, J.L.M. [St Thomas` Hospital, London (United Kingdom). St John`s Institute of Dermatology

    1995-12-01

    Our 10-year experience with PUVA treatment for alopecia areata, partialis, totalis and universalis was retrospectively reviewed using charts and follow-up questionnaires for 70 patients at St John`s Institute of Dermatology. In all cases, several previous therapies were judged to be unsatisfactory prior to starting PUVA, and many cases were already deemed clinically refractory prior to referral for PUVA. If cases of vellus hair growth are excluded, and those who lost their PUVA-induced regrowth rapidly on follow-up, the effective success rate was at best 6.3% for alopecia areata partialis, 12.5% for alopecia areata totalis and 13.3% for alopecia areata universalis. We affirm that PUVA is generally not an effective treatment for alopecia areata. (Author).

  20. Micose fungóide: estudo epidemiológico de 17 casos e avaliação da resposta terapêutica à PUVA Mycosis fungoides: epidemiologic study of 17 cases and evaluation of PUVA photochemotherapy

    Directory of Open Access Journals (Sweden)

    Ida Duarte

    2006-02-01

    Full Text Available FUNDAMENTOS: A fotoquimioterapia com PUVA é indicada para tratamento da micose fungóide, empregada como monoterapia em estágios precoces ou combinada a outras drogas nos estágios mais avançados da doença. OBJETIVOS: Avaliação da resposta terapêutica à fotoquimioterapia PUVA em pacientes com micose fungóide. MÉTODOS: Entre janeiro de 1996 e novembro de 2003 avaliaram-se 17 pacientes com micose fungóide no setor de Fototerapia da Clínica Dermatológica da Santa Casa de São Paulo. A terapia com PUVA foi realizada como monoterapia nos estádios iniciais ou como coadjuvante nos estádios avançados da doença. Avaliou-se o resultado do tratamento quanto ao aspecto clínico das lesões e parâmetros histológicos após tratamento. RESULTADOS: Quatorze de 16 pacientes responderam à fotoquimioterapia. Relacionando o estadiamento da doença à resposta terapêutica obteve-se o seguinte: cinco pacientes (um em estágio IA e quatro em IB com controle total (cura das lesões; quatro (todos IB com melhora intensa (controle de 70-99%; dois (IIB e IVA com melhora moderada (de 50 a 69%; três (IA, IB, IIA com melhora discreta (menos 50%; dois (IB, IIB inalterados (sem resposta. Um paciente teve de descontinuar o tratamento por apresentar intenso ardor. CONCLUSÃO: Houve resposta à terapia PUVA em 87% dos pacientes, com controle total ou melhora intensa da doença em 56% dos casos. Sua efetividade permitiu regressão das lesões cutâneas, principalmente nos casos precoces. A fotoquimioterapia com PUVA mostrou ser tratamento seguro e efetivo, devendo ser considerado em pacientes com micose fungóide.BACKGROUND: PUVA photochemotherapy is indicated to treat mycosis fungoides, either as monotherapy in the earlier stages of the disease or in combination with other drugs in more advanced stages of evolution. OBJECTIVES: To evaluate PUVA photochemotherapy response in patients with mycosis fungoides. METHODS: From January 1996 to November 2003, 17

  1. Kondratiev cycles and so-called long waves. The early research

    NARCIS (Netherlands)

    J. Tinbergen (Jan)

    1981-01-01

    textabstractThis paper recalls some early work of the Dutch pioneers of long-wave research which anticipated many of the contemporary debates. Various explanations which have been advanced for the existence of long waves are reviewed, and the applicability of long-wave theories in a number of

  2. Cultural Artifact Detection in Long Wave Infrared Imagery.

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Dylan Zachary [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Craven, Julia M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ramon, Eric [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-01-01

    Detection of cultural artifacts from airborne remotely sensed data is an important task in the context of on-site inspections. Airborne artifact detection can reduce the size of the search area the ground based inspection team must visit, thereby improving the efficiency of the inspection process. This report details two algorithms for detection of cultural artifacts in aerial long wave infrared imagery. The first algorithm creates an explicit model for cultural artifacts, and finds data that fits the model. The second algorithm creates a model of the background and finds data that does not fit the model. Both algorithms are applied to orthomosaic imagery generated as part of the MSFE13 data collection campaign under the spectral technology evaluation project.

  3. Long-wave, infrared laser-induced breakdown (LIBS) spectroscopy emissions from energetic materials.

    Science.gov (United States)

    Yang, Clayton S-C; Brown, Ei E; Hommerich, Uwe; Jin, Feng; Trivedi, Sudhir B; Samuels, Alan C; Snyder, A Peter

    2012-12-01

    Laser-induced breakdown spectroscopy (LIBS) has shown great promise for applications in chemical, biological, and explosives sensing and has significant potential for real-time standoff detection and analysis. In this study, LIBS emissions were obtained in the mid-infrared (MIR) and long-wave infrared (LWIR) spectral regions for potential applications in explosive material sensing. The IR spectroscopy region revealed vibrational and rotational signatures of functional groups in molecules and fragments thereof. The silicon-based detector for conventional ultraviolet-visible LIBS operations was replaced with a mercury-cadmium-telluride detector for MIR-LWIR spectral detection. The IR spectral signature region between 4 and 12 μm was mined for the appearance of MIR and LWIR-LIBS emissions directly indicative of oxygenated breakdown products as well as dissociated, and/or recombined sample molecular fragments. Distinct LWIR-LIBS emission signatures from dissociated-recombination sample molecular fragments between 4 and 12 μm are observed for the first time.

  4. The influence of scrotonin on survival of Candida guillermondii, irradiated by short-wave ultraviolet

    International Nuclear Information System (INIS)

    Strakhovskaya, M.G.; Frajkin, G.Ya.; Goncharenko, E.N.

    1982-01-01

    A study was made on the influence of serotonin on survival of Candida quilliermondu yeast irradiated by 254 nm short-wave ultraviolet. It was established that incubation with serotonin, leading to its penetration inside cells causes two opposite effects - protection from ultraviolet inactivation in preliminary incubation and intensification of cells death in postradiation incubation. Serotonin action is similar to the effects induced in C. guillermondii yeast by 334 nm long-wave ultraviolet light, that is serotonin possesses photomimetic effect. The data obtained are considered as conformaition of participation of serotonin photoinduced synthesis in manifestation of effects of long-wave ultraviolet light action on yeast

  5. An economic policy for the fifth long wave

    Directory of Open Access Journals (Sweden)

    Angelo Reati

    2004-12-01

    Full Text Available The paper starts by reviewing some recent contributions on long waves, arguing that the present technological revolution in ICT is part of the broad phenomenon of a newlong wave. It follows that the main focus of economic policy should be to support the diffusion of the new technology and to favour the institutional changes required by such an objective. Four broad guidelines are suggested: i a Keynesian policy for demand going beyond the straitjacket of the Maastricht criteria and improving the income distribution in favour of employees; i a policy to re-establish the primacy of productive capital through systematic concerted open market operations to regulate financial liquidity; iii a reconstruction of the employment relationship that preserves the essential features of the "European social model" and a targeted flexibility of labour, that contrasts with the neoclassical all-out market flexibility; and iv a regime for intellectual property rights that avoids the drawbacks--both ethical and economic--of current US practices.

  6. A non-inferiority randomized controlled clinical trial comparing Unani formulation & psoralen plus ultraviolet A sol in chronic plaque psoriasis.

    Science.gov (United States)

    Khanna, Neena; Nazli, Tamanna; Siddiqui, Khalid Mahmud; Kalaivani, Mani

    2018-01-01

    Though Unani medications have been used for centuries to treat psoriasis, there is paucity of published studies which have systematically evaluated their efficacy and safety. This study was conducted to establish non-inferiority of Unani medications (oral UNIM-401 and topical UNIM-403) vs psoralen plus ultraviolet A (PUVA) sol in treatment of moderate-severe chronic plaque psoriasis (CPP) in achieving psoriasis area severity index (PASI) 75 at 12 wk and to estimate proportion of patients who relapsed in follow up period of 12 weeks, after having achieved PASI 50. In this randomized, controlled trial patients with CPP were block randomized to receive either Unani treatment (147 patients) or PUVA sol (140 patients) for 12 weeks. Percentage reduction in PASI was determined in each patient at 12 wk to calculate number of patients who achieved PASI 75 as also to estimate median of percentage reduction in PASI in each group. All patients who achieved PASI 50 at 12 weeks were followed up for another 12 wk to determine proportion of patients who relapsed. Of the 287 patients randomized, 84 of 147 in Unani group and 67 of 140 in PUVA sol group completed 12 weeks of treatment. On intention-to-treat (ITT) analysis, the response in patients on Unani medication was not inferior to those receiving PUVA sol, in attaining PASI 75 (16.3% in Unani group vs 15.7% in the PUVA sol group). Median of percentage reduction of PASI at 12 wk from baseline in Unani group (68.2%; -60, 100) and PUVA sol group (63%; -15.7, 100) was comparable. Proportion of patients who relapsed at 24 wk was comparable in both groups. However, frequency of clinical side effects was significantly higher (P =0.001) in PUVA sol group (16.4%) compared to Unani group (2%). The findings of the present study indicated that oral UNIM-401 and topical UNIM-403 were effective and well tolerated therapeutic options in patients with moderate-severe CPP.

  7. Prophage induction, mutagenesis, and cell survival of Ames' mutagen tester strains after 8-methoxypsoralen plus ultraviolet light-A

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, L.A.; DeMeo, M. (California Univ., Los Angeles (USA)); Lowe, N. (Combined UCLA-WADSWORTH Dermatology Program, Los Angeles, CA (USA))

    1983-10-01

    8-methoxypsoralen (8-MOP) is not detected as a mutagen in the standard Ames test either in the presence or absence of S9-mix and/or ultraviolet light-A (320-400 nm). The Ames strains have been shown to harbor bacteriophages that are inducible by carcinogens and mutagens. Psoralen plus UVA (PUVA) was found to be a potent prophage inducing treatment. Induction was observed in TA1535, TA1538, TA98, TA100, TA1978 and TA1975 with 8-MOP and UVA. PUVA is a potent bactericidal treatment at concentrations of 8-MOP above 0.5 ..mu..g/ml and 2.5 kJ/m/sup 2/ in tester strains TA1535, TA1538, TA98 and TA100. PUVA is known to be bactericidal, but the cytotoxicity observed in the present study was unique in that the frameshift tester strains (TA1538 and TA98) were more sensitive to the lethal effects of PUVA than the base pair tester strains (TA1535 and TA100). The differential cytotoxicity in such closely related strains led to the examination of some of the strains from which the Ames strains were derived. It is postulated that TA1535 retains a DNA repair function that is lost by TA1538 during the selection for uvrB deficient strains.

  8. 8-MOP PUVA for psoriasis: a comparison of a minimal phototoxic dose-based regimen with a skin-type approach

    Energy Technology Data Exchange (ETDEWEB)

    Collins, P.; Wainwright, N.J.; Amorim, I.; Lakshmipathi, T.; Ferguson, J. [Ninewells Hospital and Medical School, Dundee (United Kingdom)

    1996-08-01

    Two ultraviolet A (UVA) regimens for oral 8-methoxypsoralen (8-MOP) photochemotherapy (PUVA) for moderate/severe chronic plaque psoriasis using a half-body study technique were compared. Each patient received both regimens. A higher-dose regimen based on minimal phototoxic dose (MPD) with percentage incremental increases was given to one-half of the body. The other half received a lower dose regimen based on skin type with fixed incremental UVA increases. Patients were treated twice weekly. Symmetrical plaques were scored to determine the rate of resolution with each regimen. In addition, the number of treatments, cumulative UVA dose and number of days in treatment to achieve overall clearance were recorded. Patients were reviewed monthly for one year to record remission data. Thirty-three patients completed the study. Both regimens were effective and well tolerated. With the MPD-based approach, number of exposures was significantly less for patients with skin types I and II but not III. Although the cumulative UVA dose was higher with the MPD regimen for all skin types studied, the reduced number of exposures required for clearance for skin types I and II but not III, combined with the security of individualized MPD testing, has practical attractions. MPD testing also identified five patients who required an increased psoralen dose and six patients who required a reduction of the initial UVA dose with the skin type regimen. Forty-two percent were still clear 1 year after treatment and there was no significant difference in the number of days in remission between the regimens for those whose psoriasis had recurred. The reduction in the number of exposures required for clearance with the MPD-based regimen may be safer and more cost effective in the long term. (author).

  9. Effects of selective ultraviolet phototherapy (SUP) and local PUVA treatment on DNA synthesis in Guinea pig skin

    International Nuclear Information System (INIS)

    Pullmann, H.; Galosi, A.; Jakobeit, C.; Steigleder, G.K.

    1980-01-01

    The treatment with UV-light with wavelengths between 292.5-335 nm (known as selective UV-phototherapy, or SUP) and 320-390 nm (plus local treatment with 8-methoxypsoralen, known as PUVAsub(ex)) gave rise to a biphasic reaction of epidermal cell proliferation in guinea pig skin. A decrease of proliferative activity was followed by a synchronized stimulation of DNA synthesizing cells after 2-4 h. These quantitative displacements were accompanied by qualitative changes in the proliferative behaviour of epidermal cells in the S-compartment. (orig.) [de

  10. Photoprotection due to pigmentation and epidermal thickness after repeated exposure to ultraviolet light and psoralen plus ultraviolet A therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bech-Thomsen, N.; Wulf, H.C. [Rigshospitalet, The National Univ. Hospital, Dept. of Dermatology, Lab. of Photobiology, Copenhagen (Denmark)

    1995-10-01

    Tanning and thickening of the epidermis are cardinal defensive responses of human skin to ultraviolet (UV) radiation that lead to increased photoprotection. Earlier studies have shown that skin pigmentation can be used to predict minimal erythema dose and minimal phototoxic dose. In this study it was calculated how much of the increase in photoprotection after 4 weeks of repeated exposure to suberythemogenic doses of either UVA or UVB radiation sources or psoralen plus UVA (PUVA) therapy that was attributable to melanogenesis. The backs of 12 volunteers were exposed to 6 different UVA and UVB radiation sources 9 times during 4 weeks. Skin pigmentation was assessed by skin reflectance measuring. Photoprotection was determined from the minimal erythema dose. Melanogenesis accounted for 63-95% of the increase in photoprotection after 4 weeks of exposure to UVA radiation. Exposure to two UVB sources induced a significant increase in photoprotection but not in pigmentation. Melanogenesis accounted only for 6-11% of the increase in photoprotection after 4 weeks of UVB exposure. The pigmentary and photoprotective responses to PUVA therapy were followed in 14 patients. After 2 weeks of exposure, the increase in photoprotection was significantly higher than predicted form the increase in skin pigmentation. After 4 weeks, melanogenesis accounted for only 36% of the increase in photoprotection. This study shows that melanogenesis accounts for the increased photoprotection after 2 weeks of exposure to UVA radiation, but after 4 weeks other protective mechanisms occur during suberythemal UVB exposure and during PUVA therapy the importance of skin pigmentation in the overall photoprotection gradually decreases during a 4-week irradiation period. (au) 17 refs.

  11. Photoprotection due to pigmentation and epidermal thickness after repeated exposure to ultraviolet light and psoralen plus ultraviolet A therapy

    International Nuclear Information System (INIS)

    Bech-Thomsen, N.; Wulf, H.C.

    1995-01-01

    Tanning and thickening of the epidermis are cardinal defensive responses of human skin to ultraviolet (UV) radiation that lead to increased photoprotection. Earlier studies have shown that skin pigmentation can be used to predict minimal erythema dose and minimal phototoxic dose. In this study it was calculated how much of the increase in photoprotection after 4 weeks of repeated exposure to suberythemogenic doses of either UVA or UVB radiation sources or psoralen plus UVA (PUVA) therapy that was attributable to melanogenesis. The backs of 12 volunteers were exposed to 6 different UVA and UVB radiation sources 9 times during 4 weeks. Skin pigmentation was assessed by skin reflectance measuring. Photoprotection was determined from the minimal erythema dose. Melanogenesis accounted for 63-95% of the increase in photoprotection after 4 weeks of exposure to UVA radiation. Exposure to two UVB sources induced a significant increase in photoprotection but not in pigmentation. Melanogenesis accounted only for 6-11% of the increase in photoprotection after 4 weeks of UVB exposure. The pigmentary and photoprotective responses to PUVA therapy were followed in 14 patients. After 2 weeks of exposure, the increase in photoprotection was significantly higher than predicted form the increase in skin pigmentation. After 4 weeks, melanogenesis accounted for only 36% of the increase in photoprotection. This study shows that melanogenesis accounts for the increased photoprotection after 2 weeks of exposure to UVA radiation, but after 4 weeks other protective mechanisms occur during suberythemal UVB exposure and during PUVA therapy the importance of skin pigmentation in the overall photoprotection gradually decreases during a 4-week irradiation period. (au) 17 refs

  12. Combination therapy with cyclosporine and psoralen plus ultraviolet a in the patients with severe alopecia areata: a retrospective study with a self-controlled design.

    Science.gov (United States)

    Park, Kui Young; Jang, Woo Sun; Son, In Pyeong; Choi, Sun Young; Lee, Moo Yeol; Kim, Beom Joon; Kim, Myeung Nam; Ro, Byung In

    2013-02-01

    Alopecia areata (AA) is believed to be an organ-specific autoimmune disease in which a mononuclear cell infiltrate develops in and around anagen hair follicles. There is no definitive therapy for AA. We sought to determine whether the combination therapy of cyclosporine and psoralen plus ultraviolet A (PUVA) could be an effective treatment for severe AA. A total of 41 patients with severe AA were treated with oral cyclosporine and topical PUVA. Cyclosporine was given at an initial daily dose of 200 mg for adult and 100 mg for children for periods of up to 16 weeks. Eight-methoxypsoralen (Methoxsalen) was applied topically 20 minutes prior to ultraviolet A (UVA) exposure, and the patients were irradiated with UVA twice a week for 16 weeks. Of the total 41 patients, 2 (7.3%) patients were lost to follow-up, and 1 (2.4%) patient discontinued the treatment due to abdominal discomfort. Six (14.6%) patients were treated for less than 12 weeks. Of remaining 32 patients, 3 (9.4%) showed excellent response, 3 (9.4%) showed good response, 12 (37.5%) showed fair response, and 14 (43.7%) showed poor response. Although limited by its uncontrolled character, this study shows that the combination therapy with cyclosporine and PUVA may be an additional choice for severe and recalcitrant AA.

  13. On a functional equation related to the intermediate long wave equation

    International Nuclear Information System (INIS)

    Hone, A N W; Novikov, V S

    2004-01-01

    We resolve an open problem stated by Ablowitz et al (1982 J. Phys. A: Math. Gen. 15 781) concerning the integral operator appearing in the intermediate long wave equation. We explain how this is resolved using the perturbative symmetry approach introduced by one of us with Mikhailov. By solving a certain functional equation, we prove that the intermediate long wave equation and the Benjamin-Ono equation are the unique integrable cases within a particular class of integro-differential equations. Furthermore, we explain how the perturbative symmetry approach is naturally extended to treat equations on a periodic domain. (letter to the editor)

  14. Travelling wave solutions of generalized coupled Zakharov–Kuznetsov and dispersive long wave equations

    Directory of Open Access Journals (Sweden)

    M. Arshad

    Full Text Available In this manuscript, we constructed different form of new exact solutions of generalized coupled Zakharov–Kuznetsov and dispersive long wave equations by utilizing the modified extended direct algebraic method. New exact traveling wave solutions for both equations are obtained in the form of soliton, periodic, bright, and dark solitary wave solutions. There are many applications of the present traveling wave solutions in physics and furthermore, a wide class of coupled nonlinear evolution equations can be solved by this method. Keywords: Traveling wave solutions, Elliptic solutions, Generalized coupled Zakharov–Kuznetsov equation, Dispersive long wave equation, Modified extended direct algebraic method

  15. Inherent Limitations in Mid-Wave and Long-Wave-IR Upconversion Detector

    DEFF Research Database (Denmark)

    Barh, Ajanta; Tseng, Yu-Pei; Pedersen, Christian

    2017-01-01

    Inherent limitations in terms of optical losses, selection of nonlinear crystal(s), detection efficiency and pumping conditions in mid-wave (3-5 µm) and long-wave (8-12 µm) infrared frequency upconversion modules are investigated in this paper.......Inherent limitations in terms of optical losses, selection of nonlinear crystal(s), detection efficiency and pumping conditions in mid-wave (3-5 µm) and long-wave (8-12 µm) infrared frequency upconversion modules are investigated in this paper....

  16. Variability In Long-Wave Runup as a Function of Nearshore Bathymetric Features

    Energy Technology Data Exchange (ETDEWEB)

    Dunkin, Lauren McNeill [Texas A & M Univ., College Station, TX (United States)

    2010-05-01

    Beaches and barrier islands are vulnerable to extreme storm events, such as hurricanes, that can cause severe erosion and overwash to the system. Having dunes and a wide beach in front of coastal infrastructure can provide protection during a storm, but the influence that nearshore bathymetric features have in protecting the beach and barrier island system is not completely understood. The spatial variation in nearshore features, such as sand bars and beach cusps, can alter nearshore hydrodynamics, including wave setup and runup. The influence of bathymetric features on long-wave runup can be used in evaluating the vulnerability of coastal regions to erosion and dune overtopping, evaluating the changing morphology, and implementing plans to protect infrastructure. In this thesis, long-wave runup variation due to changing bathymetric features as determined with the numerical model XBeach is quantified (eXtreme Beach behavior model). Wave heights are analyzed to determine the energy through the surfzone. XBeach assumes that coastal erosion at the land-sea interface is dominated by bound long-wave processes. Several hydrodynamic conditions are used to force the numerical model. The XBeach simulation results suggest that bathymetric irregularity induces significant changes in the extreme long-wave runup at the beach and the energy indicator through the surfzone.

  17. Generalized internal long wave equations: construction, hamiltonian structure and conservation laws

    International Nuclear Information System (INIS)

    Lebedev, D.R.

    1982-01-01

    Some aspects of the theory of the internal long-wave equations (ILW) are considered. A general class of the ILW type equations is constructed by means of the Zakharov-Shabat ''dressing'' method. Hamiltonian structure and infinite numbers of conservation laws are introduced. The considered equations are shown to be Hamiltonian in the so-called second Hamiltonian structu

  18. Mid-infrared, long wave infrared (4-12 μm) molecular emission signatures from pharmaceuticals using laser-induced breakdown spectroscopy (LIBS).

    Science.gov (United States)

    Yang, Clayton S-C; Brown, Ei E; Kumi-Barimah, Eric; Hommerich, Uwe H; Jin, Feng; Trivedi, Sudhir B; Samuels, Alan C; Snyder, A Peter

    2014-01-01

    In an effort to augment the atomic emission spectra of conventional laser-induced breakdown spectroscopy (LIBS) and to provide an increase in selectivity, mid-wave to long-wave infrared (IR), LIBS studies were performed on several organic pharmaceuticals. Laser-induced breakdown spectroscopy signature molecular emissions of target organic compounds are observed for the first time in the IR fingerprint spectral region between 4-12 μm. The IR emission spectra of select organic pharmaceuticals closely correlate with their respective standard Fourier transform infrared spectra. Intact and/or fragment sample molecular species evidently survive the LIBS event. The combination of atomic emission signatures derived from conventional ultraviolet-visible-near-infrared LIBS with fingerprints of intact molecular entities determined from IR LIBS promises to be a powerful tool for chemical detection.

  19. Net radiation of mountain cultivated Norway spruce [Picea abies (L.) Karst.] stand: evaluation of shortand long-wave radiation ratio

    Czech Academy of Sciences Publication Activity Database

    Marková, I.; Marek, Michal V.

    2011-01-01

    Roč. 53, č. 2 (2011), s. 114-122 ISSN 0071-6677 Institutional research plan: CEZ:AV0Z60870520 Keywords : downward short- and long-wave radiation * upward short- and long-wave radiation * sun elevation * clearness index Subject RIV: GK - Forestry

  20. Ultraviolet Extensions

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Side-by-Side Comparison Click on image for larger view This ultraviolet image from NASA's Galaxy Evolution Explorer shows the Southern Pinwheel galaxy, also know as Messier 83 or M83. It is located 15 million light-years away in the southern constellation Hydra. Ultraviolet light traces young populations of stars; in this image, young stars can be seen way beyond the main spiral disk of M83 up to 140,000 light-years from its center. Could life exist around one of these far-flung stars? Scientists say it's unlikely because the outlying regions of a galaxy are lacking in the metals required for planets to form. The image was taken at scheduled intervals between March 15 and May 20, 2007. It is one of the longest-exposure, or deepest, images ever taken of a nearby galaxy in ultraviolet light. Near-ultraviolet light (or longer-wavelength ultraviolet light) is colored yellow, and far-ultraviolet light is blue. What Lies Beyond the Edge of a Galaxy The side-by-side comparison shows the Southern Pinwheel galaxy, or M83, as seen in ultraviolet light (right) and at both ultraviolet and radio wavelengths (left). While the radio data highlight the galaxy's long, octopus-like arms stretching far beyond its main spiral disk (red), the ultraviolet data reveal clusters of baby stars (blue) within the extended arms. The ultraviolet image was taken by NASA's Galaxy Evolution Explorer between March 15 and May 20, 2007, at scheduled intervals. Back in 2005, the telescope first photographed M83 over a shorter period of time. That picture was the first to reveal far-flung baby stars forming up to 63,000 light-years from the edge of the main spiral disk. This came as a surprise to astronomers because a galaxy's outer territory typically lacks high densities of star-forming materials. The newest picture of M83 from the Galaxy Evolution Explorer is shown at the right, and was taken over a longer period of time. In fact, it is one of the

  1. Large-Amplitude Long-Wave Instability of a Supersonic Shear Layer

    Science.gov (United States)

    Messiter, A. F.

    1995-01-01

    For sufficiently high Mach numbers, small disturbances on a supersonic vortex sheet are known to grow in amplitude because of slow nonlinear wave steepening. Under the same external conditions, linear theory predicts slow growth of long-wave disturbances to a thin supersonic shear layer. An asymptotic formulation is given here which adds nonzero shear-layer thickness to the weakly nonlinear formulation for a vortex sheet. Spatial evolution is considered, for a spatially periodic disturbance having amplitude of the same order, in Reynolds number, as the shear-layer thickness. A quasi-equilibrium inviscid nonlinear critical layer is found, with effects of diffusion and slow growth appearing through nonsecularity condition. Other limiting cases are also considered, in an attempt to determine a relationship between the vortex-sheet limit and the long-wave limit for a thin shear layer; there appear to be three special limits, corresponding to disturbances of different amplitudes at different locations along the shear layer.

  2. Ultraviolet sterilization

    International Nuclear Information System (INIS)

    Schenck, G.O.

    1987-01-01

    Artificial ultraviolet radiation sources can supply bactericidal energy in such a high dosage that in less than a second a higher degree of disinfection is accomplished than by sun irradiation in hours. Bacteria, viruses, phages, and organic micropollutants can be degraded by photochemical wet combustion down to and below detection limits of organic carbon. There are no known ultraviolet-resistant microorganisms. There are limitations to ultraviolet treatment which can often be overcome by adequate technical measures. Unlike other water purification processes, ultraviolet irradiation only exterminates living organisms. The radiation must be able to penetrate to the objects of the kill; in a dose large enough to kill, and long enough to kill and prevent new growth. Contrary to filters, ultraviolet flow-through reactors do not restrict free flow significantly. In contrast to distillation, ultraviolet irradiation imposes no phase changes to the water. Used as a sequence in ultrapure water systems, maintenance requirements are virtually nonexistent; because of the absence of dissolved and particulate matter in purified water, mechanical cleaning of the photoreactor chambers is not essential. The process is highly economical; energy consumption is low and supervision minimal. 103 refs., 45 figs., 15 tabs

  3. A new psoralen-containing gel for topical PUVA therapy: development, and treatment results in patients with palmoplantar and plaque-type psoriasis, and hyperkeratotic eczema

    International Nuclear Information System (INIS)

    De Rie, M.A.; Van Eendenburg, J.P.; Versnick, A.C.; Stolk, L.M.L.; Bos, J.D.; Westerhof, W.

    1995-01-01

    Topical photochemotherapy with psoralen and its derivatives 4,5',8-trimethylpsoralen (TMP) and 8-methoxypsoralen (8-MOP), with UVA irradiation, was evaluated with regard to minimum phototoxic dose, concentration, timing of UVA irradiation and systemic and local side-effects, in healthy volunteers. Psoralen (0.005%) in aqueous gel was found to be superior to TMP and 8-MOP in aqueous gel. No hyperpigmentation was seen after topical PUVA treatment with psoralen in aqueous gel. Patients with plaque-type psoriasis (n=7), palmoplantar psoriasis (n=7) and hyperkeratotic eczema (n=2) were treated. Topical PUVA therapy was effective in most psoriasis patients, without the occurrence of local or systemic side-effects. Moreover, hyperkeratotic eczema patients who did not respond to conventional therapy showed partial remission. These results indicate that topical PUVA therapy with psoralen in aqueous gel is a useful therapeutic modality for treatment of psoriasis patients, and patients with recalcitrant dermatoses such as palmoplantar psoriasis and hyperkeratotic eczema. (author)

  4. Experiments on the proof of the repair of the DNA-damage in human fibroblasts in vitro, induced by PUVA-conditions and after UVC-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Silla, R.

    1979-01-01

    Within the frame of the present study we tried to investigate in vitro the course of repair of DNA-damage which had been provoked by UV C-irradiation and by PUVA-conditions. In a preliminary test series the suppression of the semiconservative DNA-replication by hydroxyurea was investigated. It resulted that there is a four-fold suppression of the programmed DNA-synthesis. In the standard experiments 5 groups with 8-MOP plus various UV A-irradiation energies were compared with the not irradiated control groups, with the groups with 8-MOP, with UV A in two different doses, and with the UV C group. The test samples were marked with /sup 3/H-thymidine, whilst hydroxurea was added after a certain period of time (0, 1, 2, 4 hours). In each case the uptake of /sup 3/H-thymidine into the DNS - as expression of repair activity - was measured after one hour by the liquid scintigraphic method. These experiments proved an obvious repair activity of the groups, which had received UV C-irradiation, and of those under PUVA-conditions with low UV A-irradiation energies. The maximum values were found after one hour or after two hours respectively. The /sup 3/H-thymidine uptake is blocked by PUVA-conditions with increasing UV A-irradiation energies. Apparently this is also valid for 8-MOP only and for high UV A-doses only.

  5. A simple formula for the net long-wave radiation flux in the southern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Tomasz Zapadka

    2001-09-01

    Full Text Available This paper discusses problems of estimating the net long-wave radiation flux at the sea surface on the basis of easily measurable meteorological quantities (air and sea surface temperatures, near-surface water vapour pressure, cloudiness. Empirical data and existing formulae are compared. Additionally, an improved formula for the southern Baltic region is introduced, with a systematic error of less than 1 W -2 and a statistical error of less than 20 W -2.

  6. Long-wave plasma radiofrequency ablation for treatment of xanthelasma palpebrarum.

    Science.gov (United States)

    Baroni, Adone

    2018-03-01

    Xanthelasma palpebrarum is the most common type of xanthoma affecting the eyelids. It is characterized by asymptomatic soft yellowish macules, papules, or plaques over the upper and lower eyelids. Many treatments are available for management of xanthelasma palpebrarum, the most commonly used include surgical excision, ablative CO 2 or erbium lasers, nonablative Q-switched Nd:YAG laser, trichloroacetic acid peeling, and radiofrequency ablation. This study aims to evaluate the effectiveness of RF ablation in the treatment of xanthelasma palpebrarum, with D.A.S. Medical portable device (Technolux, Italia), a radiofrequency tool working with long-wave plasma energy and without anesthesia. Twenty patients, 15 female and 5 male, affected by xanthelasma palpebrarum, were enrolled for long-wave plasma radiofrequency ablation treatment. The treatment consisted of 3/4 sessions that were carried out at intervals of 30 days. Treatments were well tolerated by all patients with no adverse effects and optimal aesthetic results. The procedure is very fast and can be performed without anesthesia because of the low and tolerable pain stimulation. Long-wave plasma radiofrequency ablation is an effective option for treatment of xanthelasma palpebrarum and adds an additional tool to the increasing list of medical devices for aesthetic treatments. © 2018 Wiley Periodicals, Inc.

  7. Technical considerations for designing low-cost, long-wave infrared objectives

    Science.gov (United States)

    Desroches, Gerard; Dalzell, Kristy; Robitaille, Blaise

    2014-06-01

    With the growth of uncooled infrared imaging in the consumer market, the balance between cost implications and performance criteria in the objective lens must be examined carefully. The increased availability of consumer-grade, long-wave infrared cameras is related to a decrease in military usage but it is also due to the decreasing costs of the cameras themselves. This has also driven up demand for low-cost, long-wave objectives that can resolve smaller pixels while maintaining high performance. Smaller pixels are traditionally associated with high cost objectives because of higher resolution requirements but, with careful consideration of all the requirements and proper selection of materials, costs can be moderated. This paper examines the cost/performance trade-off implications associated with optical and mechanical requirements of long-wave infrared objectives. Optical performance, f-number, field of view, distortion, focus range and thermal range all affect the cost of the objective. Because raw lens material cost is often the most expensive item in the construction, selection of the material as well as the shape of the lens while maintaining acceptable performance and cost targets were explored. As a result of these considerations, a low-cost, lightweight, well-performing objective was successfully designed, manufactured and tested.

  8. Calibrated Mid-wave Infrared (IR) (MidIR) and Long-wave IR (LWIR) Stokes and Degree-of-Liner Polarization (DOLP)

    Science.gov (United States)

    2008-09-01

    radiance from natural surfaces, was recorded continuously using an Eppley long-wave pyranometer . The long-wave pyranometer is designed to measure radiance...meteorological parameters as well as the ambient radiant loading experienced during the test recorded by the Eppley long-wave pyranometer . Tables 1

  9. Dispersion relation for long-wave neutrons and the possibility of its precise experimental verification

    International Nuclear Information System (INIS)

    Frank, A.I.; Nosov, V.G.

    1995-01-01

    Modern theoretical concepts concerning the dispersion relation for slow neutrons in matter are considered. The generally accepted optical-potential model is apparently not quite accurate and should be supplemented with some small corrections in the energy range attainable in experiments. For ultracold neutrons, these corrections are related to the proximity of the applicability boundary of the theory; for cold neutrons, these corrections are due to correlations in the positions of scatters. The accuracy of existing experiments is insufficient for confirmation or refutation these conclusions. A precision experiment is proposed to verify the dispersion relation for long-wave neutrons. 30 refs., 3 figs

  10. A Galerkin Finite Element Method for Numerical Solutions of the Modified Regularized Long Wave Equation

    Directory of Open Access Journals (Sweden)

    Liquan Mei

    2014-01-01

    Full Text Available A Galerkin method for a modified regularized long wave equation is studied using finite elements in space, the Crank-Nicolson scheme, and the Runge-Kutta scheme in time. In addition, an extrapolation technique is used to transform a nonlinear system into a linear system in order to improve the time accuracy of this method. A Fourier stability analysis for the method is shown to be marginally stable. Three invariants of motion are investigated. Numerical experiments are presented to check the theoretical study of this method.

  11. The behaviour of hydrogen-like atoms in an intense long-wave field

    International Nuclear Information System (INIS)

    Brodsky, A.M.

    1979-01-01

    The equations, which permit the calculation by means of regular operations of multiphoton photoionisation cross sections and the dynamic polarisabilities in an intense classical long-wave electromagnetic field, are considered for a hydrogen atom. The calculations have been performed for a circularly polarised field. A quantitative expression has been derived for the Lamb shift analogue, which can be verified experimentally. Within the framework of the problem the interaction at small distances is self-compensated and reduced to a constant potential. This conclusion is of general interest for the theory of strong interactions. (author)

  12. Advances in low-cost long-wave infrared polymer windows

    Science.gov (United States)

    Weimer, Wayne A.; Klocek, Paul

    1999-07-01

    Recent improvements in engineered polymeric material compositions and advances in processing methodologies developed and patented at Raytheon Systems Company have produced long wave IR windows at exceptionally low costs. These UV stabilized, high strength windows incorporating subwavelength structured antireflection surfaces are enabling IR imaging systems to penetrate commercial markets and will reduce the cost of systems delivered to the military. The optical and mechanical properties of these windows will be discussed in detail with reference to the short and long-term impact on military IR imaging systems.

  13. Numerical simulation of the regularized long wave equation by He's homotopy perturbation method

    Energy Technology Data Exchange (ETDEWEB)

    Inc, Mustafa [Department of Mathematics, Firat University, 23119 Elazig (Turkey)], E-mail: minc@firat.edu.tr; Ugurlu, Yavuz [Department of Mathematics, Firat University, 23119 Elazig (Turkey)

    2007-09-17

    In this Letter, we present the homotopy perturbation method (shortly HPM) for obtaining the numerical solution of the RLW equation. We obtain the exact and numerical solutions of the Regularized Long Wave (RLW) equation for certain initial condition. The initial approximation can be freely chosen with possible unknown constants which can be determined by imposing the boundary and initial conditions. Comparison of the results with those of other methods have led us to significant consequences. The numerical solutions are compared with the known analytical solutions.

  14. Numerical simulation of the regularized long wave equation by He's homotopy perturbation method

    International Nuclear Information System (INIS)

    Inc, Mustafa; Ugurlu, Yavuz

    2007-01-01

    In this Letter, we present the homotopy perturbation method (shortly HPM) for obtaining the numerical solution of the RLW equation. We obtain the exact and numerical solutions of the Regularized Long Wave (RLW) equation for certain initial condition. The initial approximation can be freely chosen with possible unknown constants which can be determined by imposing the boundary and initial conditions. Comparison of the results with those of other methods have led us to significant consequences. The numerical solutions are compared with the known analytical solutions

  15. Post-Colonial Africa and the World Economy: The Long Waves of Uneven Development

    Directory of Open Access Journals (Sweden)

    Fouad Makki

    2015-08-01

    Full Text Available The aim of this article is to examine the interactive dynamics of "Africa" and the "world economy" over the past half century. By relating the overarching developmental trajectory of the continent to the long-wave rhythms of the world economy, the article identifies three relatively articulated periods in the political economy of postcolonial Africa. The first, from circa 1960 to the late 1970s, was a period of state-led developmentalism enabled by the long postwar boom in the world economy and the embedded liberalism of the Bretton Woods system. A second period from circa 1980 to the turn of the new century was conditioned by the long downturn in the world-economy and a neo-li beral regime of accumulation that sought to re-structure and re-integrate Africa into a deregulated world market. The turn of the new millennium constitutes a new period in which neither the deep structural springs of the long downturn nor the neo-liberal project as such have been overcome; but their impact on Africa has been relativized by the emergence of East Asia as the new center of accumulation in the world economy. The resulting de-synchronization of the long-wave rhythms of the world economy has permitted a modest economic expansion in Africa within a largely extractive regime of accumulation and a wave of new enclosures that are profoundly reconstituting the social universe of Africa's primary producers.

  16. Satellite Based Downward Long Wave Radiation by Various Models in Northeast Asia

    Directory of Open Access Journals (Sweden)

    Chanyang Sur

    2014-01-01

    Full Text Available Satellite-based downward long wave radiation measurement under clear sky conditions in Northeast Asia was conducted using five well-known physical models (Brunt 1932, Idso and Jackson 1969, Brutsaert 1975, Satterlund 1979, Prata 1996 with a newly proposed global Rld model (Abramowitz et al. 2012. Data from two flux towers in South Korea were used to validate downward long wave radiation. Moderate resolution imaging spectroradiometer (MODIS atmospheric profile products were used to develop the Rld models. The overall root mean square error (RMSE of MODIS Rld with respect to two ecosystem-type flux towers was determined to be ≈ 20 W m-2. Based on the statistical analyses, MODIS Rld estimates with Brutsaert (1975 and Abramowitz et al. (2012 models were the most applicable for evaluating Rld for clear sky conditions in Northeast Asia. The Abramowitz Rld maps with MODIS Ta and ea showed reasonable seasonal patterns, which were well-aligned with other biophysical variables reported by previous studies. The MODIS Rld map developed in this study will be very useful for identifying spatial patterns that are not detectable from ground-based Rld measurement sites.

  17. Wave Tank Studies of Strong Modulation of Wind Ripples Due To Long Waves

    Science.gov (United States)

    Ermakov, S.; Sergievskaya, I.; Shchegolkov, Yu.

    Modulation of wind capillary-gravity ripples due to long waves has been studied in wave tank experiment at low wind speeds using Ka-band radar. The experiments were carried out both for clean water and the water surface covered with surfactant films. It is obtained that the modulation of radar signals is quite strong and can increase with surfactant concentration and fetch. It is shown that the hydrodynamic Modulation Transfer Function (MTF) calculated for free wind ripples and taking into account the kinematic (straining) effect, variations of the wind stress and variations of surfactant concentration strongly underestimates experimental MTF-values. The effect of strong modulation is assumed to be connected with nonlinear harmonics of longer dm-cm- scale waves - bound waves ("parasitic ripples"). The intensity of bound waves depends strongly on the amplitude of decimetre-scale waves, therefore even weak modulation of the dm-scale waves due to long waves results to strong ("cascade") modulation of bound waves. Modulation of the system of "free/bound waves" is estimated using results of wave tank studies of bound waves generation and is shown to be in quali- tative agreement with experiment. This work was supported by MOD, UK via DERA Winfrith (Project ISTC 1774P) and by RFBR (Project 02-05-65102).

  18. Propagation of Tsunami-like Surface Long Waves in the Bays of a Variable Depth

    Directory of Open Access Journals (Sweden)

    A.Yu. Bazykina

    2016-08-01

    Full Text Available Within the framework of the nonlinear long wave theory the regularities of solitary long wave propagation in the semi-closed bays of model and real geometry are numerically studied. In the present article the zones of wave amplification in the bay are found. The first one is located near the wave running-up on the beach (in front of the bay entrance and the other one – in the middle part of the sea basin. Wave propagation in these zones is accompanied both by significant rise and considerable fall of the sea level. Narrowing of the bay entrance and increase of the entering wave length result in decrease of the sea level maximum rises and falls. The Feodosiya Gulf in the Black Sea is considered as a real basin. In general the dynamics of the waves in the gulf is similar to wave dynamics in the model bay. Four zones of the strongest wave amplification in the Feodosiya Gulf are revealed in the article. The sea level maximum rises and extreme falls which tend to grow with decrease of the entering wave length are observed in these zones. The distance traveled by the wave before the collapse (due to non-linear effects, was found to reduce with decreasing wavelength of the entrance to the bay (gulf.

  19. Long-wave theory for a new convective instability with exponential growth normal to the wall.

    Science.gov (United States)

    Healey, J J

    2005-05-15

    A linear stability theory is presented for the boundary-layer flow produced by an infinite disc rotating at constant angular velocity in otherwise undisturbed fluid. The theory is developed in the limit of long waves and when the effects of viscosity on the waves can be neglected. This is the parameter regime recently identified by the author in a numerical stability investigation where a curious new type of instability was found in which disturbances propagate and grow exponentially in the direction normal to the disc, (i.e. the growth takes place in a region of zero mean shear). The theory describes the mechanisms controlling the instability, the role and location of critical points, and presents a saddle-point analysis describing the large-time evolution of a wave packet in frames of reference moving normal to the disc. The theory also shows that the previously obtained numerical solutions for numerically large wavelengths do indeed lie in the asymptotic long-wave regime, and so the behaviour and mechanisms described here may apply to a number of cross-flow instability problems.

  20. Qual é o tipo de fototerapia mais comumente indicada no tratamento da psoríase?: UVB banda estreita e PUVA: comportamento da prescrição What is the most common phototherapy prescription for psoriasis: NB-UVB or PUVA? Prescription behavior

    Directory of Open Access Journals (Sweden)

    Ida Duarte

    2009-07-01

    Full Text Available FUNDAMENTOS: Formas moderada e grave de psoríase requerem fototerapia e/ou medicações sistêmicas. Tanto UVB banda estreita quanto fototerapia UVA com psoralênicos (PUVA podem ser utilizadas no tratamento dessas formas de psoríase, sendo comprovada a efetividade de ambas as terapias. OBJETIVOS: Avaliar as indicações de dois tipos de fototerapia no tratamento da psoríase refratária à terapia tópica: UVB banda estreita e PUVA. MÉTODOS: Entre janeiro de 2006 e dezembro de 2007, os pacientes encaminhados a dois serviços de fototerapia foram incluídos neste estudo. Dados sobre os casos e tipos de prescrição foram coletados de maneira retrospectiva. RESULTADOS: Dentre os 67 pacientes estudados, 51 (76% foram tratados com UVB banda estreita. As razões para sua indicação foram presença de psoríase em gotas (22%, presença de finas placas (15%, uso de drogas fotossensibilizantes (15%, idade abaixo de 20 anos (9%, fototipo I (9% e doença hepática (6%. Os 16 (24% restantes foram tratados com PUVA. A principal indicação dessa terapia foi gravidade da doença (15%, seguida de fototipo IV (9%. CONCLUSÕES: As prescrições de UVB banda estreita excederam as de PUVA devido ao menor número de contraindicações, menor possibilidade de efeitos colaterais, e ainda por ser uma opção mais prática.BACKGROUND: Moderate and severe forms of psoriasis require phototherapy and / or systemic medications. Both UVA and UVB can be used to treat cases of moderate and severe psoriasis, and the effectiveness of both has been proven. OBJECTIVE: to access the prescription behavior relating to two types of phototherapy for treating psoriasis refractory to topical treatment: narrowband UVB (NB-UVB or psoralen plus UVA phototherapy (PUVA. METHODS: Between January 2006 and December 2007, patients referred to two phototherapy services were included in this study. Data on the cases and on the type of prescription were collected retrospectively. RESULTS

  1. Drying of Agricultural Products Using Long Wave Infrared Radiation(Part 2). Drying of Welsh Onion

    International Nuclear Information System (INIS)

    Itoh, K.; Han, C.S.

    1995-01-01

    The investigation was carried out to clarify the intermittent drying characteristics for welsh onion use of long-wave infrared radiation. When compared with two other methods: use of air and vacuum freezing, this method showed significantly high rate of drying. The experiments were carried out analyzing the influence of different lengths of the welsh onion, different rate of radiation and different temperature of the airflow. The obtained results were as follows: 1. The rate of drying increases as the length of welsh onion decrease and the rate of radiation increase. 2. The airflow, temperature does not influence to the rate of drying. 3. The increasing of the drying time considerably aggravate the quality the dried welsh onion

  2. Generalized intermediate long-wave hierarchy in zero-curvature representation with noncommutative spectral parameter

    Science.gov (United States)

    Degasperis, A.; Lebedev, D.; Olshanetsky, M.; Pakuliak, S.; Perelomov, A.; Santini, P. M.

    1992-11-01

    The simplest generalization of the intermediate long-wave hierarchy (ILW) is considered to show how to extend the Zakharov-Shabat dressing method to nonlocal, i.e., integro-partial differential, equations. The purpose is to give a procedure of constructing the zero-curvature representation of this class of equations. This result obtains by combining the Drinfeld-Sokolov formalism together with the introduction of an operator-valued spectral parameter, namely, a spectral parameter that does not commute with the space variable x. This extension provides a connection between the ILWk hierarchy and the Saveliev-Vershik continuum graded Lie algebras. In the case of ILW2 the Fairlie-Zachos sinh-algebra was found.

  3. High intersubband absorption in long-wave quantum well infrared photodetector based on waveguide resonance

    Science.gov (United States)

    Zheng, Yuanliao; Chen, Pingping; Ding, Jiayi; Yang, Heming; Nie, Xiaofei; Zhou, Xiaohao; Chen, Xiaoshuang; Lu, Wei

    2018-06-01

    A hybrid structure consisting of periodic gold stripes and an overlaying gold film has been proposed as the optical coupler of a long-wave quantum well infrared photodetector. Absorption spectra and field distributions of the structure at back-side normal incidence are calculated by the finite difference time-domain method. The results indicate that the intersubband absorption can be greatly enhanced based on the waveguide resonance as well as the surface plasmon polariton (SPP) mode. With the optimized structural parameters of the periodic gold stripes, the maximal intersubband absorption can exceed 80%, which is much higher than the SPP-enhanced intersubband absorption (the one of the standard device. The relationship between the structural parameters and the waveguide resonant wavelength is derived. Other advantages of the efficient optical coupling based on waveguide resonance are also discussed.

  4. A simulation model for the actual, long wave and net solar radiation computing

    International Nuclear Information System (INIS)

    Kolev, B.; Stoilov, A.; Lyubomirov, L.

    2004-01-01

    The main purpose of this study is to present a calculating procedure for the components of the radiation balance - actual, long-wave and net radiation calculation, using the sunshine duration and the standard meteorological information, through a previously prepared program product.To calculate the actual solar radiation using the total cloudiness only, an empirical regression model has been developed. The results of the coefficient of correlation R(0.75-0.88), respectively for the spring and summer periods (March-May; June-August) show the adequacy of the chosen model. The verification of the model on the independent experimental material prove that the approach that authors suggested, can be successfully applied to the calculation of the actual radiation of the current place

  5. Long-Wave Infrared (LWIR) Molecular Laser-Induced Breakdown Spectroscopy (LIBS) Emissions of Thin Solid Explosive Powder Films Deposited on Aluminum Substrates.

    Science.gov (United States)

    Yang, Clayton S-C; Jin, Feng; Trivedi, Sudhir B; Brown, Ei E; Hommerich, Uwe; Tripathi, Ashish; Samuels, Alan C

    2017-04-01

    Thin solid films made of high nitro (NO 2 )/nitrate (NO 3 ) content explosives were deposited on sand-blasted aluminum substrates and then studied using a mercury-cadmium-telluride (MCT) linear array detection system that is capable of rapidly capturing a broad spectrum of atomic and molecular laser-induced breakdown spectroscopy (LIBS) emissions in the long-wave infrared region (LWIR; ∼5.6-10 µm). Despite the similarities of their chemical compositions and structures, thin films of three commonly used explosives (RDX, HMX, and PETN) studied in this work can be rapidly identified in the ambient air by their molecular LIBS emission signatures in the LWIR region. A preliminary assessment of the detection limit for a thin film of RDX on aluminum appears to be much lower than 60 µg/cm 2 . This LWIR LIBS setup is capable of rapidly probing and charactering samples without the need for elaborate sample preparation and also offers the possibility of a simultaneous ultraviolet visible and LWIR LIBS measurement.

  6. Solar ultraviolet hazards

    International Nuclear Information System (INIS)

    Azmah Ali

    1995-01-01

    The paper discussed the following subjects: the sources of ultraviolet radiation, solar ultraviolet radiation definition, effects of over exposure to solar ultraviolet radiation, exposure limits and radiation protection of this radiation

  7. Long-wave equivalent viscoelastic solids for porous rocks saturated by two-phase fluids

    Science.gov (United States)

    Santos, J. E.; Savioli, G. B.

    2018-04-01

    Seismic waves traveling across fluid-saturated poroelastic materials with mesoscopic-scale heterogeneities induce fluid flow and Biot's slow waves generating energy loss and velocity dispersion. Using Biot's equations of motion to model these type of heterogeneities would require extremely fine meshes. We propose a numerical upscaling procedure to determine the complex and frequency dependent P-wave and shear moduli of an effective viscoelastic medium long-wave equivalent to a poroelastic solid saturated by a two-phase fluid. The two-phase fluid is defined in terms of capillary pressure and relative permeability flow functions. The P-wave and shear effective moduli are determined using harmonic compressibility and shear experiments applied on representative samples of the bulk material. Each experiment is associated with a boundary value problem that is solved using the finite element method. Since a poroelastic solid saturated by a two-phase fluid supports the existence of two slow waves, this upscaling procedure allows to analyze their effect on the mesoscopic-loss mechanism in hydrocarbon reservoir formations. Numerical results show that a two-phase Biot medium model predicts higher attenuation than classic Biot models.

  8. Long-wave model for strongly anisotropic growth of a crystal step.

    Science.gov (United States)

    Khenner, Mikhail

    2013-08-01

    A continuum model for the dynamics of a single step with the strongly anisotropic line energy is formulated and analyzed. The step grows by attachment of adatoms from the lower terrace, onto which atoms adsorb from a vapor phase or from a molecular beam, and the desorption is nonnegligible (the "one-sided" model). Via a multiscale expansion, we derived a long-wave, strongly nonlinear, and strongly anisotropic evolution PDE for the step profile. Written in terms of the step slope, the PDE can be represented in a form similar to a convective Cahn-Hilliard equation. We performed the linear stability analysis and computed the nonlinear dynamics. Linear stability depends on whether the stiffness is minimum or maximum in the direction of the step growth. It also depends nontrivially on the combination of the anisotropy strength parameter and the atomic flux from the terrace to the step. Computations show formation and coarsening of a hill-and-valley structure superimposed onto a long-wavelength profile, which independently coarsens. Coarsening laws for the hill-and-valley structure are computed for two principal orientations of a maximum step stiffness, the increasing anisotropy strength, and the varying atomic flux.

  9. Modelling of long-wave chaotic radar system for anti-stealth applications

    Science.gov (United States)

    Al-Suhail, Ghaida A.; Tahir, Fadhil Rahma; Abd, Mariam Hussien; Pham, Viet-Thanh; Fortuna, Luigi

    2018-04-01

    Although the Very Low-Frequency (VLF) waveforms have limited practical applications in acoustics (sonar) and secure military communications with radars and submarines; to this end; this paper presents a new and simple analytical model of VLF monostatic direct chaotic radar system. The model hypothetically depends on the two identical coupled time-delayed feedback chaotic systems which can generate and recover a long-wave chaotic signal. To resist the influence of positive Lyapunov exponents of the time-delay chaotic systems, the complete replacement of Pecaro and Carroll (PC) synchronization is employed. It can faithfully recover the chaotic signal from the back-scattered (echo) signal from the target over a noisy channel. The system performance is characterized in terms of the time series of synchronization in addition to the peak of the cross-correlation. Simulation results are conducted for substantial sensitivities of the chaotic signal to the system parameters and initial conditions. As a result, it is found that an effective and robust chaotic radar (CRADAR) model can be obtained when the signal-to-noise ratio (SNR) highly degrades to 0 dB, but with clear peak in correlation performance for detecting the target. Then, the model can be considered as a state of the art towards counter stealth technology and might be developed for other acoustic secure applications.

  10. Mathematical investigation of tsunami-like long waves interaction with submerge dike of different thickness

    Science.gov (United States)

    Zhiltsov, Konstantin; Kostyushin, Kirill; Kagenov, Anuar; Tyryshkin, Ilya

    2017-11-01

    This paper presents a mathematical investigation of the interaction of a long tsunami-type wave with a submerge dike. The calculations were performed by using the freeware package OpenFOAM. Unsteady two-dimensional Navier-Stokes equations were used for mathematical modeling of incompressible two-phase medium. The Volume of Fluid (VOF) method is used to capture the free surface of a liquid. The effects caused by long wave of defined amplitude motion through a submerged dike of varying thickness were discussed in detail. Numerical results show that after wave passing through the barrier, multiple vortex structures were formed behind. Intensity of vortex depended on the size of the barrier. The effectiveness of the submerge barrier was estimated by evaluating the wave reflection and transmission coefficients using the energy integral method. Then, the curves of the dependences of the reflection and transmission coefficients were obtained for the interaction of waves with the dike. Finally, it was confirmed that the energy of the wave could be reduced by more than 50% when it passed through the barrier.

  11. Ultraviolet radiation

    International Nuclear Information System (INIS)

    Hawk, J.

    1986-01-01

    Ultraviolet radiation (UVR) from the sun or artificial sources is reflected or transmitted at the surface of the skin, about 5% of normally incident rays being directly reflected. The transmitted fraction is scattered, photochemically absorbed or dissipated as heat within the skin, or passes from it to contribute to the variable total amount of reflected and transmitted radiation. The UVR absorbers in skin are not definitely known, but DNA is a definite target and probably lipoprotein membranes, RNA, proteins, mucopolysaccharides, elastin and collagen. Photochemical or free radical damage to absorber or nearby organelles leads to pharmacological, ultrastructural, histological and clinical changes. Most frequent DNA damage is pyrimidine dimer formation, apparently inhibiting cell function and replication. This is largely enzymatically repaired in man in the dark by excision repair, post-replication repair and possible other enzymatic mechanisms, and at least in some organisms by light-induced photoreactivation repair. UVR exposure causes well recognized acute and chronic clinical syndromes in man. These are discussed in this paper

  12. Long-wave-instability-induced pattern formation in an evaporating sessile or pendent liquid layer

    Science.gov (United States)

    Wei, Tao; Duan, Fei

    2018-03-01

    We investigate the nonlinear dynamics and stability of an evaporating liquid layer subject to vapor recoil, capillarity, thermocapillarity, ambient cooling, viscosity, and negative or positive gravity combined with buoyancy effects in the lubrication approximation. Using linear theory, we identify the mechanisms of finite-time rupture, independent of thermocapillarity and direction of gravity, and predict the effective growth rate of an interfacial perturbation which reveals competition among the mechanisms. A stability diagram is predicted for the onset of long-wave (LW) evaporative convection. In the two-dimensional simulation, we observe well-defined capillary ridges on both sides of the valley under positive gravity and main and secondary droplets under negative gravity, while a ridge can be trapped in a large-scale drained region in both cases. Neglecting the other non-Boussinesq effects, buoyancy does not have a significant influence on interfacial evolution and rupture time but makes contributions to the evaporation-driven convection and heat transfer. The average Nusselt number is found to increase with a stronger buoyancy effect. The flow field and interface profile jointly manifest the LW Marangoni-Rayleigh-Bénard convection under positive gravity and the LW Marangoni convection under negative gravity. In the three-dimensional simulation of moderate evaporation with a random perturbation, the rupture patterns are characterized by irregular ridge networks with distinct height scales for positive and negative gravity. A variety of interfacial and internal dynamics are displayed, depending on evaporation conditions, gravity, Marangoni effect, and ambient cooling. Reasonable agreement is found between the present results and the reported experiments and simulations. The concept of dissipative compacton also sheds light on the properties of interfacial fractalization.

  13. Long-wave UVA offers partial protection against UVB-induced

    DEFF Research Database (Denmark)

    Skov, L.; Villadsen, L.; Ersbøll, Bjarne Kjær

    2000-01-01

    Ultraviolet-B (UVB, 280–320 nm) interferes with the generation of cell-mediated immunity to contact allergens applied epicutaneously on the irradiated site. To investigate whether pretreatment with UVA-1 (340–400 nm) protects against the UVB-induced immune suppression we sensitized human volunteers...... with diphenylcyclopropenone (DPCP) on normal buttock skin (n=12), on UVB-irradiated buttock skin (n=21), on buttock skin pretreated with UVA-1 (n=12), and on buttock skin pretreated with UVA-1 and thereafter irradiated with UVB (n=22). Sensitization on UVB-irradiated skin reduced the immunization rate to DPCP compared...

  14. Extended Jacobi Elliptic Function Rational Expansion Method and Its Application to (2+1)-Dimensional Stochastic Dispersive Long Wave System

    International Nuclear Information System (INIS)

    Song Lina; Zhang Hongqing

    2007-01-01

    In this work, by means of a generalized method and symbolic computation, we extend the Jacobi elliptic function rational expansion method to uniformly construct a series of stochastic wave solutions for stochastic evolution equations. To illustrate the effectiveness of our method, we take the (2+1)-dimensional stochastic dispersive long wave system as an example. We not only have obtained some known solutions, but also have constructed some new rational formal stochastic Jacobi elliptic function solutions.

  15. Four-Wave Mixing of Gigawatt Power, Long-Wave Infrared Radiation in Gases and Semiconductors

    Science.gov (United States)

    Pigeon, Jeremy James

    The nonlinear optics of gigawatt power, 10 microm, 3 and 200 ps long pulses propagating in gases and semiconductors has been studied experimentally and numerically. In this work, the development of a high-repetition rate, picosecond, CO2 laser system has enabled experiments using peak intensities in the range of 1-10 GW/cm2, approximately one thousand times greater than previous nonlinear optics experiments in the long-wave infrared (LWIR) spectral region. The first measurements of the nonlinear refractive index of the atomic and molecular gases Kr, Xe, N2, O2 and the air at a wavelength near 10 microm were accomplished by studying the four-wave mixing (FWM) of dual-wavelength, 200 ps CO2 laser pulses. These measurements indicate that the nonlinearities of the diatomic molecules N2, O2 and the air are dominated by the molecular contribution to the nonlinear refractive index. Supercontinuum (SC) generation covering the infrared spectral range, from 2-20 microm, was realized by propagating 3 ps, 10 microm pulses in an approximately 7 cm long, Cr-doped GaAs crystal. Temporal measurements of the SC radiation show that pulse splitting accompanies the generation of such broadband light in GaAs. The propagation of 3 ps, 10 microm pulses in GaAs was studied numerically by solving the Generalized Nonlinear Schrodinger Equation (GNLSE). These simulations, combined with analytic estimates, were used to determine that stimulated Raman scattering combined with a modulational instability caused by the propagation of intense LWIR radiation in the negative group velocity dispersion region of GaAs are responsible for the SC generation process. The multiple FWM of a 106 GHz, 200 ps CO2 laser beat-wave propagating in GaAs was used to generate a broadband FWM spectrum that was compressed by the negative group velocity dispersion of GaAs and NaCl crystals to form trains of high-power, picosecond pulses at a wavelength near 10 microm. Experimental FWM spectra obtained using 165 and 882

  16. Ultra-Trace Chemical Sensing with Long-Wave Infrared Cavity-Enhanced Spectroscopic Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Taubman, Matthew S.; Myers, Tanya L.; Cannon, Bret D.; Williams, Richard M.; Schultz, John F.

    2003-02-20

    The infrared sensors task of Pacific Northwest National Laboratory's (PNNL's) Remote Spectroscopy Project (Task B of Project PL211) is focused on the science and technology of remote and in-situ spectroscopic chemical sensors for detecting proliferation and coun-tering terrorism. Missions to be addressed by remote chemical sensor development in-clude detecting proliferation of nuclear or chemical weapons, and providing warning of terrorist use of chemical weapons. Missions to be addressed by in-situ chemical sensor development include countering terrorism by screening luggage, personnel, and shipping containers for explosives, firearms, narcotics, chemical weapons, or chemical weapons residues, and mapping contaminated areas. The science and technology is also relevant to chemical weapons defense, air operations support, monitoring emissions from chemi-cal weapons destruction or industrial activities, law enforcement, medical diagnostics, and other applications. Sensors for most of these missions will require extreme chemical sensitivity and selectiv-ity because the signature chemicals of importance are expected to be present in low con-centrations or have low vapor pressures, and the ambient air is likely to contain pollutants or other chemicals with interfering spectra. Cavity-enhanced chemical sensors (CES) that draw air samples into optical cavities for laser-based interrogation of their chemical content promise real-time, in-situ chemical detection with extreme sensitivity to specified target molecules and superb immunity to spectral interference and other sources of noise. PNNL is developing CES based on quantum cascade (QC) lasers that operate in the mid-wave infrared (MWIR - 3 to 5 microns) and long-wave infrared (LWIR - 8 to 14 mi-crons), and CES based on telecommunications lasers operating in the short-wave infrared (SWIR - 1 to 2 microns). All three spectral regions are promising because smaller mo-lecular absorption cross sections in the SWIR

  17. Thermal and ghost reflection modeling for a 180-deg. field-of-view long-wave infrared lens

    Science.gov (United States)

    Shi, Weimin; Couture, Michael E.

    2001-03-01

    Optics 1, Inc. has successfully designed and developed a 180 degree(s) field of view long wave infrared lens for USAF/AFRL under SBIR phase I and II funded projects in support of the multi-national Programmable Integrated Ordinance Suite (PIOS) program. In this paper, a procedure is presented on how to evaluate image degradation caused by asymmetric aerodynamic dome heating. In addition, a thermal gradient model is proposed to evaluate degradation caused by axial temperature gradient throughout the entire PIOS lens. Finally, a ghost reflection analysis is demonstrated with non-sequential model.

  18. Applications of exact traveling wave solutions of Modified Liouville and the Symmetric Regularized Long Wave equations via two new techniques

    Science.gov (United States)

    Lu, Dianchen; Seadawy, Aly R.; Ali, Asghar

    2018-06-01

    In this current work, we employ novel methods to find the exact travelling wave solutions of Modified Liouville equation and the Symmetric Regularized Long Wave equation, which are called extended simple equation and exp(-Ψ(ξ))-expansion methods. By assigning the different values to the parameters, different types of the solitary wave solutions are derived from the exact traveling wave solutions, which shows the efficiency and precision of our methods. Some solutions have been represented by graphical. The obtained results have several applications in physical science.

  19. Multicomponent long-wave-short-wave resonance interaction system: Bright solitons, energy-sharing collisions, and resonant solitons.

    Science.gov (United States)

    Sakkaravarthi, K; Kanna, T; Vijayajayanthi, M; Lakshmanan, M

    2014-11-01

    We consider a general multicomponent (2+1)-dimensional long-wave-short-wave resonance interaction (LSRI) system with arbitrary nonlinearity coefficients, which describes the nonlinear resonance interaction of multiple short waves with a long wave in two spatial dimensions. The general multicomponent LSRI system is shown to be integrable by performing the Painlevé analysis. Then we construct the exact bright multisoliton solutions by applying the Hirota's bilinearization method and study the propagation and collision dynamics of bright solitons in detail. Particularly, we investigate the head-on and overtaking collisions of bright solitons and explore two types of energy-sharing collisions as well as standard elastic collision. We have also corroborated the obtained analytical one-soliton solution by direct numerical simulation. Also, we discuss the formation and dynamics of resonant solitons. Interestingly, we demonstrate the formation of resonant solitons admitting breather-like (localized periodic pulse train) structure and also large amplitude localized structures akin to rogue waves coexisting with solitons. For completeness, we have also obtained dark one- and two-soliton solutions and studied their dynamics briefly.

  20. Long-wave Irradiance Measurement and Modeling during Snowmelt, a Case Study in the Yukon Territory, Canada

    Science.gov (United States)

    Sicart, J.; Essery, R.; Pomeroy, J.

    2004-12-01

    At high latitudes, long-wave radiation emitted by the atmosphere and solar radiation can provide similar amounts of energy for snowmelt due to the low solar elevation and the high albedo of snow. This paper investigates temporal and spatial variations of long-wave irradiance at the snow surface in an open sub-Arctic environment. Measurements were conducted in the Wolf Creek Research Basin, Yukon Territory, Canada (60°36'N, 134°57'W) during the springs of 2002, 2003 and 2004. The main causes of temporal variability are air temperature and cloud cover, especially in the beginning of the melting period when the atmosphere is still cold. Spatial variability was investigated through a sensitivity study to sky view factors and to temperatures of surrounding terrain. The formula of Brutsaert gives a useful estimation of the clear-sky irradiance at hourly time steps. Emission by clouds was parameterized at the daily time scale from the atmospheric attenuation of solar radiation. The inclusion of air temperature variability does not much improve the calculation of cloud emission.

  1. An open labeled, comparative clinical study on efficacy and tolerability of oral minipulse of steroid (OMP alone, OMP with PUVA and broad / narrow band UVB phototherapy in progressive vitiligo

    Directory of Open Access Journals (Sweden)

    Rath Namita

    2008-01-01

    Full Text Available Background: Several modalities of treatment have been tried in vitiligo with varied results; however, Indian data on comparative studies of two or more therapies are limited. Aims: We compared different phototherapy methods with an oral steroid as an adjunct to determine the method with the best tolerability and efficacy. Methods: Eighty-six patients with progressive vitiligo were randomly assigned to different study groups according to a continuous selection method over a period of one year. Group 1 was given OMP + PUVA, group 2 OMP + UVB (NB, group 3 OMP + UVB (BB and group 4 was given OMP alone. Each patient was followed up for six months and then released from treatment. Clinical evaluation was made at the end of three and six months. Results: In group 1 (OMP + PUVA, marked improvement was seen in 18.51% while moderate improvement was seen in 66.66% of the patients. Marked improvement was seen in 37.03% in group 2 (OMP + NB-UVB while 44.44% had moderate improvement. In group 3 (OMP + BB UVB, 8.33% showed marked improvement while moderate improvement was seen in 25% of the patients. Marked and moderate improvement was seen in 5 and 10% of group 4 (OMP patients, respectively. Conclusions: Our study compared four treatment modalities in vitiligo patients, out of which oral minipulse of steroids (OMP only had an adjunct value and was not very effective by itself. Narrow band UVB has a definite edge over broad band UVB and should be preferred when both options are available. NB-UVB and PUVA showed comparable efficacy.

  2. Mutations induced by ultraviolet light

    International Nuclear Information System (INIS)

    Pfeifer, Gerd P.; You, Young-Hyun; Besaratinia, Ahmad

    2005-01-01

    The different ultraviolet (UV) wavelength components, UVA (320-400 nm), UVB (280-320 nm), and UVC (200-280 nm), have distinct mutagenic properties. A hallmark of UVC and UVB mutagenesis is the high frequency of transition mutations at dipyrimidine sequences containing cytosine. In human skin cancers, about 35% of all mutations in the p53 gene are transitions at dipyrimidines within the sequence 5'-TCG and 5'-CCG, and these are localized at several mutational hotspots. Since 5'-CG sequences are methylated along the p53 coding sequence in human cells, these mutations may be derived from sunlight-induced pyrimidine dimers forming at sequences that contain 5-methylcytosine. Cyclobutane pyrimidine dimers (CPDs) form preferentially at dipyrimidines containing 5-methylcytosine when cells are irradiated with UVB or sunlight. In order to define the contribution of 5-methylcytosine to sunlight-induced mutations, the lacI and cII transgenes in mouse fibroblasts were used as mutational targets. After 254 nm UVC irradiation, only 6-9% of the base substitutions were at dipyrimidines containing 5-methylcytosine. However, 24-32% of the solar light-induced mutations were at dipyrimidines that contain 5-methylcytosine and most of these mutations were transitions. Thus, CPDs forming preferentially at dipyrimidines with 5-methylcytosine are responsible for a considerable fraction of the mutations induced by sunlight in mammalian cells. Using mouse cell lines harboring photoproduct-specific photolyases and mutational reporter genes, we showed that CPDs (rather than 6-4 photoproducts or other lesions) are responsible for the great majority of UVB-induced mutations. An important component of UVB mutagenesis is the deamination of cytosine and 5-methylcytosine within CPDs. The mutational specificity of long-wave UVA (340-400 nm) is distinct from that of the shorter wavelength UV and is characterized mainly by G to T transversions presumably arising through mechanisms involving oxidized DNA

  3. Comparative analysis of different approaches to the computation of long-wave radiation balance of water air systems

    International Nuclear Information System (INIS)

    Zhukovskii, K.; Nourani, Y.; Monte, L.

    1999-01-01

    In the present paper, the net long-wave radiation balance of the water-air environmental systems is analysed on the base of several semi-empirical approaches. Various theoretical models of infrared atmospheric radiation are reviewed. Factors, affecting their behavior are considered. Special attention is paid to physical conditions under which those models are applicable. Atmospheric and net infrared radiation fluxes are computed and compared under clear and cloudy sky. Results are presented in graphical form. Conclusions are made on the applicability of models considered for evaluating infrared radiation fluxes in environmental conditions of Central Italy. On the base of present analysis Anderson's model is chosen for future calculations of heat budget of lakes in Central Italy [it

  4. The investigation for (2+1)-dimensional Eckhaus-type extension of the dispersive long wave equation

    International Nuclear Information System (INIS)

    Yan Zhenya

    2004-01-01

    The (2+1)-dimensional Eckhaus-type extension of the dispersive long wave (EEDLW) equation is investigated, which was obtained in the appropriate approximation from the basic equations of hydrodynamics. Though it has no Painleve property, we gain an auto-Baecklund transformation (aBT) by truncating the Laurent series expansion at O(w 0 ). In particular, the special one of the aBT establishes a relationship between the EEDLW equation and a set of three linear partial differential equations involving the well-known heat equation. Finally many types of new exact solutions of the EEDLW equation are found from the obtained aBT and some proper ansaetze, which may be useful to explain some physical phenomena

  5. The Method of Lines Solution of the Regularized Long-Wave Equation Using Runge-Kutta Time Discretization Method

    Directory of Open Access Journals (Sweden)

    H. O. Bakodah

    2013-01-01

    Full Text Available A method of lines approach to the numerical solution of nonlinear wave equations typified by the regularized long wave (RLW is presented. The method developed uses a finite differences discretization to the space. Solution of the resulting system was obtained by applying fourth Runge-Kutta time discretization method. Using Von Neumann stability analysis, it is shown that the proposed method is marginally stable. To test the accuracy of the method some numerical experiments on test problems are presented. Test problems including solitary wave motion, two-solitary wave interaction, and the temporal evaluation of a Maxwellian initial pulse are studied. The accuracy of the present method is tested with and error norms and the conservation properties of mass, energy, and momentum under the RLW equation.

  6. The modified extended Fan's sub-equation method and its application to (2 + 1)-dimensional dispersive long wave equation

    International Nuclear Information System (INIS)

    Yomba, Emmanuel

    2005-01-01

    By using a modified extended Fan's sub-equation method, we have obtained new and more general solutions including a series of non-travelling wave and coefficient function solutions namely: soliton-like solutions, triangular-like solutions, single and combined non-degenerative Jacobi elliptic wave function-like solutions for the (2 + 1)-dimensional dispersive long wave equation. The most important achievement of this method lies on the fact that, we have succeeded in one move to give all the solutions which can be previously obtained by application of at least four methods (method using Riccati equation, or first kind elliptic equation, or auxiliary ordinary equation, or generalized Riccati equation as mapping equation)

  7. An extended Jacobi elliptic function rational expansion method and its application to (2+1)-dimensional dispersive long wave equation

    International Nuclear Information System (INIS)

    Wang Qi; Chen Yong; Zhang Hongqing

    2005-01-01

    With the aid of computerized symbolic computation, a new elliptic function rational expansion method is presented by means of a new general ansatz, in which periodic solutions of nonlinear partial differential equations that can be expressed as a finite Laurent series of some of 12 Jacobi elliptic functions, is more powerful than exiting Jacobi elliptic function methods and is very powerful to uniformly construct more new exact periodic solutions in terms of rational formal Jacobi elliptic function solution of nonlinear partial differential equations. As an application of the method, we choose a (2+1)-dimensional dispersive long wave equation to illustrate the method. As a result, we can successfully obtain the solutions found by most existing Jacobi elliptic function methods and find other new and more general solutions at the same time. Of course, more shock wave solutions or solitary wave solutions can be gotten at their limit condition

  8. Photodetector of ultraviolet radiation

    International Nuclear Information System (INIS)

    Dorogan, V.; Branzari, V.; Vieru, T.; Manole, M.; Canter, V.

    2000-01-01

    The invention relates to photodetectors on base of semiconductors of ultraviolet radiation and may be used in optoelectronic system for determining the intensity and the dose of ultraviolet radiation emitted by the Sun or other sources. Summary of the invention consists in the fact that in the photodetector of ultraviolet radiation the superficial potential barrier is divided into two identical elements, electrically isolated each of the other, one of them being covered with a layer of transparent material for visible and infrared radiation and absorption the ultra violet radiation. The technical result consists in mutual compensation of visible and infrared components of the radiation spectrum

  9. Nonlinear interaction between a pair of oblique modes in a supersonic mixing layer: Long-wave limit

    Science.gov (United States)

    Balsa, Thomas F.; Gartside, James

    1995-01-01

    The nonlinear interaction between a pair of symmetric, oblique, and spatial instability modes is studied in the long-wave limit using asymptotic methods. The base flow is taken to be a supersonic mixing layer whose Mach number is such that the corresponding vortex sheet is marginally stable according to Miles' criterion. It is shown that the amplitude of the mode obeys a nonlinear integro-differential equation. Numerical solutions of this equation show that, when the obliqueness angle is less than pi/4, the effect of the nonlinearity is to enhance the growth rate of the instability. The solution terminates in a singularity at a finite streamwise location. This result is reminiscent of that obtained in the vicinity of the neutral point by other authors in several different types of flows. On the other hand, when the obliqueness angle is more than pi/4, the streamwise development of the amplitude is characterized by a series of modulations. This arises from the fact that the nonlinear term in the amplitude equation may be either stabilizing or destabilizing, depending on the value of the streamwise coordinate. However, even in this case the amplitude of the disturbance increases, though not as rapidly as in the case for which the angle is less than pi/4. Quite generally then, the nonlinear interaction between two oblique modes in a supersonic mixing layer enhances the growth of the disturbance.

  10. Shutterless non-uniformity correction for the long-term stability of an uncooled long-wave infrared camera

    Science.gov (United States)

    Liu, Chengwei; Sui, Xiubao; Gu, Guohua; Chen, Qian

    2018-02-01

    For the uncooled long-wave infrared (LWIR) camera, the infrared (IR) irradiation the focal plane array (FPA) receives is a crucial factor that affects the image quality. Ambient temperature fluctuation as well as system power consumption can result in changes of FPA temperature and radiation characteristics inside the IR camera; these will further degrade the imaging performance. In this paper, we present a novel shutterless non-uniformity correction method to compensate for non-uniformity derived from the variation of ambient temperature. Our method combines a calibration-based method and the properties of a scene-based method to obtain correction parameters at different ambient temperature conditions, so that the IR camera performance can be less influenced by ambient temperature fluctuation or system power consumption. The calibration process is carried out in a temperature chamber with slowly changing ambient temperature and a black body as uniform radiation source. Enough uniform images are captured and the gain coefficients are calculated during this period. Then in practical application, the offset parameters are calculated via the least squares method based on the gain coefficients, the captured uniform images and the actual scene. Thus we can get a corrected output through the gain coefficients and offset parameters. The performance of our proposed method is evaluated on realistic IR images and compared with two existing methods. The images we used in experiments are obtained by a 384× 288 pixels uncooled LWIR camera. Results show that our proposed method can adaptively update correction parameters as the actual target scene changes and is more stable to temperature fluctuation than the other two methods.

  11. Ultraviolet radiation and immunosuppression.

    LENUS (Irish Health Repository)

    Murphy, G M

    2009-11-01

    Ultraviolet (UV) radiation is a complete carcinogen. The effects of UV radiation are mediated via direct damage to cellular DNA in the skin and suppression of image surveillance mechanisms. In the context of organ transplantation, addiction of drugs which suppress the immune system add greatly to the carcinogenicity of UV radiation. This review considers the mechanisms of such effects.

  12. Stellar extreme ultraviolet astronomy

    International Nuclear Information System (INIS)

    Cash, W.C. Jr.

    1978-01-01

    The design, calibration, and launch of a rocket-borne imaging telescope for extreme ultraviolet astronomy are described. The telescope, which employed diamond-turned grazing incidence optics and a ranicon detector, was launched November 19, 1976, from the White Sands Missile Range. The telescope performed well and returned data on several potential stellar sources of extreme ultraviolet radiation. Upper limits ten to twenty times more sensitive than previously available were obtained for the extreme ultraviolet flux from the white dwarf Sirius B. These limits fall a factor of seven below the flux predicted for the star and demonstrate that the temperature of Sirius B is not 32,000 K as previously measured, but is below 30,000 K. The new upper limits also rule out the photosphere of the white dwarf as the source of the recently reported soft x-rays from Sirius. Two other white dwarf stars, Feige 24 and G191-B2B, were observed. Upper limits on the flux at 300 A were interpreted as lower limits on the interstellar hydrogen column densities to these stars. The lower limits indicate interstellar hydrogen densitites of greater than .02 cm -3 . Four nearby stars (Sirius, Procyon, Capella, and Mirzam) were observed in a search for intense low temperature coronae or extended chromospheres. No extreme ultraviolet radiation from these stars was detected, and upper limits to their coronal emisson measures are derived

  13. Ultraviolet fire detector

    Science.gov (United States)

    Turnage, J. E.; Linford, R. M. F.; Cornish, S. D.

    1976-01-01

    System is capable of detecting ultraviolet light emitted by match size flame at distance of 10 ft. System is not affected by high energy or particulate radiation and is therefore particularly suited for applications around nuclear plants and X-ray equipment.

  14. Psoriasis and ultraviolet radiation

    International Nuclear Information System (INIS)

    Farber, E.M.; Nall, L.

    1993-01-01

    Prevention and detection screening programs as a public health service in curtailing the ever-increasing incidence of all forms of skin cancer are reviewed. The effect of solar and artificial ultraviolet radiation on the general population and persons with psoriasis is examined. 54 refs

  15. The collision of multimode dromions and a firewall in the two-component long-wave-short-wave resonance interaction equation

    International Nuclear Information System (INIS)

    Radha, R; Kumar, C Senthil; Lakshmanan, M; Gilson, C R

    2009-01-01

    In this communication, we investigate the two-component long-wave-short-wave resonance interaction equation and show that it admits the Painleve property. We then suitably exploit the recently developed truncated Painleve approach to generate exponentially localized solutions for the short-wave components S (1) and S (2) while the long wave L admits a line soliton only. The exponentially localized solutions driving the short waves S (1) and S (2) in the y-direction are endowed with different energies (intensities) and are called 'multimode dromions'. We also observe that the multimode dromions suffer from intramodal inelastic collision while the existence of a firewall across the modes prevents the switching of energy between the modes. (fast track communication)

  16. A series of new soliton-like solutions and double-like periodic solutions of a (2 + 1)-dimensional dispersive long wave equation

    International Nuclear Information System (INIS)

    Yong Chen; Qi Wang

    2005-01-01

    In this paper, we extend the algebraic method proposed by Fan (Chaos, Solitons and Fractals 20 (2004) 609) and the improved extended tanh method by Yomba (Chaos, Solitons and Fractals 20 (2004) 1135) to uniformly construct a series of soliton-like solutions and double-like periodic solutions for nonlinear partial differential equations (NPDE). Some new soliton-like solutions and double-like periodic solutions of a (2 + 1)-dimensional dispersive long wave equation are obtained

  17. Analysis of the Electronic Crosstalk Effect in Terra MODIS Long-Wave Infrared Photovoltaic Bands Using Lunar Images

    Science.gov (United States)

    Wilson, Truman; Wu, Aisheng; Wang, Zhipeng; Xiong, Xiaoxiong

    2016-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) is one of the key sensors among the suite of remote sensing instruments on board the Earth Observing System Terra and Aqua spacecrafts. For each MODIS spectral band, the sensor degradation has been measured using a set of on-board calibrators. MODIS also uses lunar observations from nearly monthly spacecraft maneuvers, which bring the Moon into view through the space-view port, helping to characterize the scan mirror degradation at a different angles of incidence. Throughout the Terra mission, contamination of the long-wave infrared photovoltaic band (LWIR PV, bands 27-30) signals has been observed in the form of electronic crosstalk, where signal from each of the detectors among the LWIR PV bands can leak to the other detectors, producing a false signal contribution. This contamination has had a noticeable effect on the MODIS science products since 2010 for band 27, and since 2012 for bands 28 and 29. Images of the Moon have been used effectively for determining the contaminating bands, and have also been used to derive correction coefficients for the crosstalk contamination. In this paper, we introduce an updated technique for characterizing the crosstalk contamination among the LWIR PV bands using data from lunar calibration events. This approach takes into account both the in-band and out-of-band contribution to the signal contamination for each detector in bands 27-30, which is not considered in previous works. The crosstalk coefficients can be derived for each lunar calibration event, providing the time dependence of the crosstalk contamination. Application of these coefficients to Earth-view image data results in a significant reduction in image contamination and a correction of the scene radiance for bands 27- 30. Also, this correction shows a significant improvement to certain threshold tests in the MODIS Level-2 Cloud Mask. In this paper, we will detail the methodology used to identify and correct

  18. Occupational applications of ultraviolet radiation

    International Nuclear Information System (INIS)

    Eriksen, P.

    1987-01-01

    A large population of workers are exposed to ultraviolet radiation in various occupational environments which often necessitates protection. Since ultraviolet radiation may create other environmental problems an occupational hazard- and protection evaluation can be complicated. Threshold Limit Values adopted by the American Conference of Governmental Industrial Hygienists (ACGIH) on ultraviolet radiation are used in most countries as guidelines for risk assessment and control measures. This review addresses the levels of ultraviolet radiation met in occupational environments, its measurement and evaluation, and discusses different protection methods. Ultraviolet lasers are beginning to find their way into industrial processes but are still limited in number and they will not be covered here. Emphasis is on broad band incoherent radiation in high risk environments such as welding, and on the evaluation of protective eyewear, see-through curtains and plastics. Other occupational risks associated with the emission of ultraviolet radiation are discussed

  19. Transparent ultraviolet photovoltaic cells.

    Science.gov (United States)

    Yang, Xun; Shan, Chong-Xin; Lu, Ying-Jie; Xie, Xiu-Hua; Li, Bing-Hui; Wang, Shuang-Peng; Jiang, Ming-Ming; Shen, De-Zhen

    2016-02-15

    Photovoltaic cells have been fabricated from p-GaN/MgO/n-ZnO structures. The photovoltaic cells are transparent to visible light and can transform ultraviolet irradiation into electrical signals. The efficiency of the photovoltaic cells is 0.025% under simulated AM 1.5 illumination conditions, while it can reach 0.46% under UV illumination. By connecting several such photovoltaic cells in a series, light-emitting devices can be lighting. The photovoltaic cells reported in this Letter may promise the applications in glass of buildings to prevent UV irradiation and produce power for household appliances in the future.

  20. Uptake of donor lymphocytes treated with 8-methoxypsoralen and ultraviolet A light by recipient dendritic cells induces CD4+CD25+Foxp3+ regulatory T cells and down-regulates cardiac allograft rejection

    International Nuclear Information System (INIS)

    Zheng, De-Hua; Dou, Li-Ping; Wei, Yu-Xiang; Du, Guo-Sheng; Zou, Yi-Ping; Song, Ji-Yong; Zhu, Zhi-Dong; Cai, Ming; Qian, Ye-Yong; Shi, Bing-Yi

    2010-01-01

    Extracorporeal photopheresis (ECP) is an effective immunomodulatory therapy and has been demonstrated to be beneficial for graft-vs-host disease and solid-organ allograft rejection. ECP involves reinfusion of a patient's autologous peripheral blood leukocytes treated ex vivo with 8-methoxypsoralen and UVA light radiation (PUVA). Previous studies focused only on ECP treatment of recipient immune cells. Our study is the first to extend the target of ECP treatment to donor immune cells. The results of in vitro co-culture experiments demonstrate uptake of donor PUVA-treated splenic lymphocytes (PUVA-SPs) by recipient immature dendritic cells (DCs). Phagocytosis of donor PUVA-SPs does not stimulate phenotype maturation of recipient DCs. In the same co-culture system, donor PUVA-SPs enhanced production of interleukin-10 and interferon-γ by recipient DCs and impaired the subsequent capability of recipient DCs to stimulate recipient naive T cells. Phagocytosis of donor PUVA-SP (PUVA-SP DCs) by recipient DCs shifted T-cell responses in favor of T helper 2 cells. Infusion of PUVA-SP DCs inhibited cardiac allograft rejection in an antigen-specific manner and induced CD4 + CD25 high Foxp3 + regulatory T cells. In conclusion, PUVA-SP DCs simultaneously deliver the donor antigen and the regulatory signal to the transplant recipient, and thus can be used to develop a novel DC vaccine for negative immune regulation and immune tolerance induction.

  1. Uptake of donor lymphocytes treated with 8-methoxypsoralen and ultraviolet A light by recipient dendritic cells induces CD4{sup +}CD25{sup +}Foxp3{sup +} regulatory T cells and down-regulates cardiac allograft rejection

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, De-Hua [Organ Transplant Center, Chinese PLA 309th Hospital, No. 17A Hei-Shan-Hu Road, Beijing 100091 (China); Dou, Li-Ping [Department of Hematology, Chinese PLA General Hospital, No. 28 Fu-Xing Road, Beijing 100853 (China); Wei, Yu-Xiang; Du, Guo-Sheng; Zou, Yi-Ping; Song, Ji-Yong; Zhu, Zhi-Dong; Cai, Ming; Qian, Ye-Yong [Organ Transplant Center, Chinese PLA 309th Hospital, No. 17A Hei-Shan-Hu Road, Beijing 100091 (China); Shi, Bing-Yi, E-mail: shibingyi@medmail.com.cn [Organ Transplant Center, Chinese PLA 309th Hospital, No. 17A Hei-Shan-Hu Road, Beijing 100091 (China)

    2010-05-14

    Extracorporeal photopheresis (ECP) is an effective immunomodulatory therapy and has been demonstrated to be beneficial for graft-vs-host disease and solid-organ allograft rejection. ECP involves reinfusion of a patient's autologous peripheral blood leukocytes treated ex vivo with 8-methoxypsoralen and UVA light radiation (PUVA). Previous studies focused only on ECP treatment of recipient immune cells. Our study is the first to extend the target of ECP treatment to donor immune cells. The results of in vitro co-culture experiments demonstrate uptake of donor PUVA-treated splenic lymphocytes (PUVA-SPs) by recipient immature dendritic cells (DCs). Phagocytosis of donor PUVA-SPs does not stimulate phenotype maturation of recipient DCs. In the same co-culture system, donor PUVA-SPs enhanced production of interleukin-10 and interferon-{gamma} by recipient DCs and impaired the subsequent capability of recipient DCs to stimulate recipient naive T cells. Phagocytosis of donor PUVA-SP (PUVA-SP DCs) by recipient DCs shifted T-cell responses in favor of T helper 2 cells. Infusion of PUVA-SP DCs inhibited cardiac allograft rejection in an antigen-specific manner and induced CD4{sup +}CD25{sup high}Foxp3{sup +} regulatory T cells. In conclusion, PUVA-SP DCs simultaneously deliver the donor antigen and the regulatory signal to the transplant recipient, and thus can be used to develop a novel DC vaccine for negative immune regulation and immune tolerance induction.

  2. Effect of long-wave UV radiation on mouse melanoma: An in vitro and in vivo study

    Energy Technology Data Exchange (ETDEWEB)

    Pastila, R.

    2006-04-15

    The skin cancer incidence has increased substantially over the past decades and the role of ultraviolet (UV) radiation in the etiology of skin cancer is well established. Ultraviolet B radiation (280-320 nm) is commonly considered as the more harmful part of the UV-spectrum due to its DNA-damaging potential and well-known carcinogenic effects. Ultraviolet A radiation (320-400 nm) is still regarded as a relatively low health hazard. However, UVA radiation is the predominant component in sunlight, constituting more than 90% of the environmentally relevant solar ultraviolet radiation. In the light of the recent scientific evidence, UVA has been shown to have genotoxic and immunologic effects, and it has been proposed that UVA plays a significant role in the development of skin cancer. Due to the popularity of skin tanning lamps, which emit high intensity UVA radiation and because of the prolonged sun tanning periods with the help of effective UVB blockers, the potential deleterious effects of UVA has emerged as a source of concern for public health. The possibility that UV radiation may affect melanoma metastasis has not been addressed before. UVA radiation can modulate various cellular processes, some of which might affect the metastatic potential of melanoma cells. The aim of the present study was to investigate the possible role of UVA irradiation on the metastatic capacity of mouse melanoma both in vitro and in vivo. The in vitro part of the study dealt with the enhancement of the intercellular interactions occurring either between tumor cells or between tumor cells and endothelial cells after UVA irradiation. The use of the mouse melanoma/endothelium in vitro model showed that a single-dose of UVA to melanoma cells causes an increase in melanoma cell adhesiveness to non-irradiated endothelium after 24-h irradiation. Multiple-dose irradiation of melanoma cells already increased adhesion at a 1-h time-point, which suggests the possible cumulative effect of multiple

  3. Effect of long-wave UV radiation on mouse melanoma: An in vitro and in vivo study

    International Nuclear Information System (INIS)

    Pastila, R.

    2006-04-01

    The skin cancer incidence has increased substantially over the past decades and the role of ultraviolet (UV) radiation in the etiology of skin cancer is well established. Ultraviolet B radiation (280-320 nm) is commonly considered as the more harmful part of the UV-spectrum due to its DNA-damaging potential and well-known carcinogenic effects. Ultraviolet A radiation (320-400 nm) is still regarded as a relatively low health hazard. However, UVA radiation is the predominant component in sunlight, constituting more than 90% of the environmentally relevant solar ultraviolet radiation. In the light of the recent scientific evidence, UVA has been shown to have genotoxic and immunologic effects, and it has been proposed that UVA plays a significant role in the development of skin cancer. Due to the popularity of skin tanning lamps, which emit high intensity UVA radiation and because of the prolonged sun tanning periods with the help of effective UVB blockers, the potential deleterious effects of UVA has emerged as a source of concern for public health. The possibility that UV radiation may affect melanoma metastasis has not been addressed before. UVA radiation can modulate various cellular processes, some of which might affect the metastatic potential of melanoma cells. The aim of the present study was to investigate the possible role of UVA irradiation on the metastatic capacity of mouse melanoma both in vitro and in vivo. The in vitro part of the study dealt with the enhancement of the intercellular interactions occurring either between tumor cells or between tumor cells and endothelial cells after UVA irradiation. The use of the mouse melanoma/endothelium in vitro model showed that a single-dose of UVA to melanoma cells causes an increase in melanoma cell adhesiveness to non-irradiated endothelium after 24-h irradiation. Multiple-dose irradiation of melanoma cells already increased adhesion at a 1-h time-point, which suggests the possible cumulative effect of multiple

  4. New exact solutions to MKDV-Burgers equation and (2 + 1)-dimensional dispersive long wave equation via extended Riccati equation method

    International Nuclear Information System (INIS)

    Kong Cuicui; Wang Dan; Song Lina; Zhang Hongqing

    2009-01-01

    In this paper, with the aid of symbolic computation and a general ansaetz, we presented a new extended rational expansion method to construct new rational formal exact solutions to nonlinear partial differential equations. In order to illustrate the effectiveness of this method, we apply it to the MKDV-Burgers equation and the (2 + 1)-dimensional dispersive long wave equation, then several new kinds of exact solutions are successfully obtained by using the new ansaetz. The method can also be applied to other nonlinear partial differential equations.

  5. Efficient Long Wave IR Laser from Ho:YAG 2 {mu}m Pumped ZnGeP{sub 2} Optical Parametric Oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Li-Gang,; Bao-Quan, Yao; Xiao-Ming, Duan; Guo-Li, Zhu; Yue-Zhu, Wang; You-Lun, Ju [National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2010-01-15

    An efficient high power long wave infrared laser based on ZnGeP{sub 2} optical parametric oscillator pumped by a 2.09 {mu}m Tm:YLF/Ho:YAG laser at 10KHz pulse repetition rate is reported. The pump to idler conversion efficiency is 8% at 15.6 W Ho pump power level and a quantum efficiency of 31 % when the 1'idler wavelength is tuned at 8.08 {mu}m. The wavelength tuning range from 8-9.1 {mu}m is also achieved by rotating the ZGP crystal. (fundamental areas of phenomenology(including applications))

  6. Dynamics of lumps and dark-dark solitons in the multi-component long-wave-short-wave resonance interaction system

    Science.gov (United States)

    Rao, Jiguang; Porsezian, Kuppuswamy; He, Jingsong; Kanna, Thambithurai

    2018-01-01

    General semi-rational solutions of an integrable multi-component (2+1)-dimensional long-wave-short-wave resonance interaction system comprising multiple short waves and a single long wave are obtained by employing the bilinear method. These solutions describe the interactions between various types of solutions, including line rogue waves, lumps, breathers and dark solitons. We only focus on the dynamical behaviours of the interactions between lumps and dark solitons in this paper. Our detailed study reveals two different types of excitation phenomena: fusion and fission. It is shown that the fundamental (simplest) semi-rational solutions can exhibit fission of a dark soliton into a lump and a dark soliton or fusion of one lump and one dark soliton into a dark soliton. The non-fundamental semi-rational solutions are further classified into three subclasses: higher-order, multi- and mixed-type semi-rational solutions. The higher-order semi-rational solutions show the process of annihilation (production) of two or more lumps into (from) one dark soliton. The multi-semi-rational solutions describe N(N≥2) lumps annihilating into or producing from N-dark solitons. The mixed-type semi-rational solutions are a hybrid of higher-order semi-rational solutions and multi-semi-rational solutions. For the mixed-type semi-rational solutions, we demonstrate an interesting dynamical behaviour that is characterized by partial suppression or creation of lumps from the dark solitons.

  7. Dynamics of lumps and dark-dark solitons in the multi-component long-wave-short-wave resonance interaction system.

    Science.gov (United States)

    Rao, Jiguang; Porsezian, Kuppuswamy; He, Jingsong; Kanna, Thambithurai

    2018-01-01

    General semi-rational solutions of an integrable multi-component (2+1)-dimensional long-wave-short-wave resonance interaction system comprising multiple short waves and a single long wave are obtained by employing the bilinear method. These solutions describe the interactions between various types of solutions, including line rogue waves, lumps, breathers and dark solitons. We only focus on the dynamical behaviours of the interactions between lumps and dark solitons in this paper. Our detailed study reveals two different types of excitation phenomena: fusion and fission. It is shown that the fundamental (simplest) semi-rational solutions can exhibit fission of a dark soliton into a lump and a dark soliton or fusion of one lump and one dark soliton into a dark soliton. The non-fundamental semi-rational solutions are further classified into three subclasses: higher-order, multi- and mixed-type semi-rational solutions. The higher-order semi-rational solutions show the process of annihilation (production) of two or more lumps into (from) one dark soliton. The multi-semi-rational solutions describe N ( N ≥2) lumps annihilating into or producing from N -dark solitons. The mixed-type semi-rational solutions are a hybrid of higher-order semi-rational solutions and multi-semi-rational solutions. For the mixed-type semi-rational solutions, we demonstrate an interesting dynamical behaviour that is characterized by partial suppression or creation of lumps from the dark solitons.

  8. Ultraviolet photovoltaics: Share the spectrum

    Science.gov (United States)

    Milliron, Delia J.

    2017-08-01

    Electrically controlled windows require power to switch between transparent and tinted states. Now, an ultraviolet light-harvesting solar cell can power smart windows without compromising their control over heat and light.

  9. Solar ultraviolet radiation cataract.

    Science.gov (United States)

    Löfgren, Stefan

    2017-03-01

    Despite being a treatable disease, cataract is still the leading cause for blindness in the world. Solar ultraviolet radiation is epidemiologically linked to cataract development, while animal and in vitro studies prove a causal relationship. However, the pathogenetic pathways for the disease are not fully understood and there is still no perfect model for human age related cataract. This non-comprehensive overview focus on recent developments regarding effects of solar UV radiation wavebands on the lens. A smaller number of fundamental papers are also included to provide a backdrop for the overview. Future studies are expected to further clarify the cellular and subcellular mechanisms for UV radiation-induced cataract and especially the isolated or combined temporal and spatial effects of UVA and UVB in the pathogenesis of human cataract. Regardless of the cause for cataract, there is a need for advances in pharmaceutical or other treatment modalities that do not require surgical replacement of the lens. Copyright © 2016. Published by Elsevier Ltd.

  10. Ultraviolet radiation and cyanobacteria.

    Science.gov (United States)

    Rastogi, Rajesh Prasad; Sinha, Rajeshwar P; Moh, Sang Hyun; Lee, Taek Kyun; Kottuparambil, Sreejith; Kim, Youn-Jung; Rhee, Jae-Sung; Choi, Eun-Mi; Brown, Murray T; Häder, Donat-Peter; Han, Taejun

    2014-12-01

    Cyanobacteria are the dominant photosynthetic prokaryotes from an ecological, economical, or evolutionary perspective, and depend on solar energy to conduct their normal life processes. However, the marked increase in solar ultraviolet radiation (UVR) caused by the continuous depletion of the stratospheric ozone shield has fueled serious concerns about the ecological consequences for all living organisms, including cyanobacteria. UV-B radiation can damage cellular DNA and several physiological and biochemical processes in cyanobacterial cells, either directly, through its interaction with certain biomolecules that absorb in the UV range, or indirectly, with the oxidative stress exerted by reactive oxygen species. However, cyanobacteria have a long history of survival on Earth, and they predate the existence of the present ozone shield. To withstand the detrimental effects of solar UVR, these prokaryotes have evolved several lines of defense and various tolerance mechanisms, including avoidance, antioxidant production, DNA repair, protein resynthesis, programmed cell death, and the synthesis of UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin. This study critically reviews the current information on the effects of UVR on several physiological and biochemical processes of cyanobacteria and the various tolerance mechanisms they have developed. Genomic insights into the biosynthesis of MAAs and scytonemin and recent advances in our understanding of the roles of exopolysaccharides and heat shock proteins in photoprotection are also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Ultraviolet radiation in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Taalas, P.; Koskela, T.; Damski, J.; Supperi, A. [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research; Kyroe, E. [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1996-12-31

    Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities have become a part of international activities, especially the EU Environment and Climate Programme`s research projects. The main national level effort has been the Finnish Academy`s climatic change programme, SILMU 1990-95. This presentation summarises the scientific results reached during the SILMU project

  12. Ultraviolet radiation: the eye

    International Nuclear Information System (INIS)

    Cesarini, J.P.; Sliney, D.H.

    1996-01-01

    Under most conditions, the eye is well adapted to protect itself against ultraviolet radiation encountered in the outdoor environment as a result of the exposure geometry of the sun. Only when snow is on the ground does one experience acute effects of UV sunlight exposure (i.e. snow blindness, or photokeratitis). With regard to artificial sources, there are many occasions where one views bright light sources such as tungsten-halogen lamps, arc lamps and welding arcs. Such viewing is normally only momentary because of the aversion response to bright light and due to discomfort glare. However, such an aversion does not take place for germicidal lamps and other UV lamps which do not contain a strong visible component in their spectrum. The adverse effects from viewing such sources has been studied for decades and during the last two decades guidelines for limiting exposure to protect the eye have been developed. The guidelines were fostered to a large extent by the growing use of lasers and the quickly recognized hazard posed by viewing laser sources. (author)

  13. Ultraviolet radiation in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Taalas, P; Koskela, T; Damski, J; Supperi, A [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research; Kyroe, E [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

    1997-12-31

    Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities have become a part of international activities, especially the EU Environment and Climate Programme`s research projects. The main national level effort has been the Finnish Academy`s climatic change programme, SILMU 1990-95. This presentation summarises the scientific results reached during the SILMU project

  14. Ultraviolet Communication for Medical Applications

    Science.gov (United States)

    2015-06-01

    DEI procured several UVC phosphors and tested them with vacuum UV (VUV) excitation. Available emission peaks include: 226 nm, 230 nm, 234 nm, 242...SUPPLEMENTARY NOTES Report contains color. 14. ABSTRACT Under this Phase II SBIR effort, Directed Energy Inc.’s (DEI) proprietary ultraviolet ( UV ...15. SUBJECT TERMS Non-line-of-sight (NLOS), networking, optical communication, plasma-shells, short range, ultraviolet ( UV ) light 16. SECURITY

  15. ULTRAVIOLET TECHNOLOGY FOR FOOD PRESERVATION

    OpenAIRE

    Guedes, AMM; Novello, D; Mendes, GMD; Cristianini, M

    2009-01-01

    ULTRAVIOLET TECHNOLOGY FOR FOOD PRESERVATION This literature review article had as objective to gather information about ultraviolet (UV) technology utilization on the food industry, its effects and potential application. Aspects as the origin, concept and applications of the technology on the equipment industry and running mechanisms were approached. The application of UV radiation on food decontamination is still little used due its low penetration, but it is known that it can be easily app...

  16. Nuclear antigen expression by ultraviolet light irradiation - a contribution to the UV-induced autoimmunity

    Energy Technology Data Exchange (ETDEWEB)

    Wollina, U

    1986-05-01

    A review is given of nuclear antigen expression due to UVB, UVA, and PUVA. UVB alters DNA resulting in strong immunogenic UVDNA and complementary antibodies. Antibodies to UVDNA cross react with double-stranded DNA. UVDNA plays a (hypothetical) role in the induction of cutaneous lesions in lupus erythematosus (LE). Investigations of SS-A/Ro expression due to UVB seem to be more important under this view. Antibodies against SS-A/Ro are related to an increased photosensitivity in LE. PUVA and UVA are able to induce antinuclear antibodies of unknown specificity. It is likely that PUVA enhances SS-A/Ro expression in vitro. The results are discussed in sense of LE photobiology and unwanted side effects of photo(chemo)therapy in psoriasis. 54 references.

  17. Nuclear antigen expression by ultraviolet light irradiation - a contribution to the UV-induced autoimmunity

    International Nuclear Information System (INIS)

    Wollina, U.

    1986-01-01

    A review is given about nuclear antigen expression due to UVB, UVA, and PUVA. UVB alters DNA resulting in strong immunogenic UVDNA and complementary antibodies. Antibodies to UVDNA cross react with double-stranded DNA. UVDNA plays a (hypothetical) role in the induction of cutaneous lesions in lupus erythematosus (LE). Investigations about SS-A/Ro expression due to UVB seem to be more important under this view. Antibodies against SS-A/Ro are related to an increased photosensitivity in LE. PUVA and UVA are able to induce antinuclear antibodies of unknown specificity. It is likely that PUVA enhances SS-A/Ro expression in vitro. The results are discussed in sense of LE photobiology and unwanted side effects of photo(chemo)therapy in psoriasis. (author)

  18. Exhaustive Classification of the Invariant Solutions for a Specific Nonlinear Model Describing Near Planar and Marginally Long-Wave Unstable Interfaces for Phase Transition

    Science.gov (United States)

    Ahangari, Fatemeh

    2018-05-01

    Problems of thermodynamic phase transition originate inherently in solidification, combustion and various other significant fields. If the transition region among two locally stable phases is adequately narrow, the dynamics can be modeled by an interface motion. This paper is devoted to exhaustive analysis of the invariant solutions for a modified Kuramoto-Sivashinsky equation in two spatial and one temporal dimensions is presented. This nonlinear partial differential equation asymptotically characterizes near planar interfaces, which are marginally long-wave unstable. For this purpose, by applying the classical symmetry method for this model the classical symmetry operators are attained. Moreover, the structure of the Lie algebra of symmetries is discussed and the optimal system of subalgebras, which yields the preliminary classification of group invariant solutions is constructed. Mainly, the Lie invariants corresponding to the infinitesimal symmetry generators as well as associated similarity reduced equations are also pointed out. Furthermore, the nonclassical symmetries of this nonlinear PDE are also comprehensively investigated.

  19. Relative role of subinertial and superinertial modes in the coastal long wave response forced by the landfall of a tropical cyclone

    Science.gov (United States)

    Ke, Ziming; Yankovsky, Alexander E.

    2011-06-01

    A set of numerical experiments has been performed in order to analyze the long-wave response of the coastal ocean to a translating mesoscale atmospheric cyclone approaching the coastline at a normal angle. An idealized two-slope shelf topography is chosen. The model is forced by a radially symmetric atmospheric pressure perturbation with a corresponding gradient wind field. The cyclone's translation speed, radius, and the continental shelf width are considered as parameters whose impact on the long wave period, modal structure, and amplitude is studied. Subinertial continental shelf waves (CSW) dominate the response under typical forcing conditions and on the narrower shelves. They propagate in the downstream (in the sense of Kelvin wave propagation) direction. Superinertial edge wave modes have higher free surface amplitudes and faster phase speeds than the CSW modes. While potentially more dangerous, edge waves are not as common as subinertial shelf waves because their generation requires a wide, gently sloping shelf and a storm system translating at a relatively high (˜10 m s -1 or faster) speed. A relatively smaller size of an atmospheric cyclone also favors edge wave generation. Edge waves with the highest amplitude (up to 60% of the forced storm surge) propagate upstream. They are produced by a storm system with an Eulerian time scale equal to the period of a zero-mode edge wave with the wavelength of the storm spatial scale. Large amplitude edge waves were generated during Hurricane Wilma's landfall (2005) on the West Florida shelf with particularly severe flooding occurring upstream of the landfall site.

  20. Harmful effects of ultraviolet radiation

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Tanning for cosmetic purposes by sunbathing or by using artificial tanning devices is widespread. The hazards associated with exposure to ultraviolet radiation are of concern to the medical profession. Depending on the amount and form of the radiation, as well as on the skin type of the individual exposed, ultraviolet radiation causes erythema, sunburn, photodamage (photoaging), photocarcinogenesis, damage to the eyes, alteration of the immune system of the skin, and chemical hypersensitivity. Skin cancers most commonly produced by ultraviolet radiation are basal and squamous cell carcinomas. There also is much circumstantial evidence that the increase in the incidence of cutaneous malignant melanoma during the past half century is related to increased sun exposure, but this has not been proved. Effective and cosmetically acceptable sunscreen preparations have been developed that can do much to prevent or reduce most harmful effects to ultraviolet radiation if they are applied properly and consistently. Other safety measures include (1) minimizing exposure to ultraviolet radiation, (2) being aware of reflective surfaces while in the sun, (3) wearing protective clothing, (4) avoiding use of artificial tanning devices, and (5) protecting infants and children

  1. Future Directions in Ultraviolet Spectroscopy

    Science.gov (United States)

    Sonneborn, George (Editor); Moos, Warren; VanSteenberg, Michael

    2009-01-01

    The 'Future Directions in Ultraviolet Spectroscopy' conference was inspired by the accomplishments of the Far Ultraviolet Spectroscopic Explorer (FUSE) Mission. The FUSE mission was launched in June 1999 and spent over eight years exploring the far-ultraviolet universe, gathering over 64 million seconds of high-resolution spectral data on nearly 3000 astronomical targets. The goal of this conference was not only to celebrate the accomplishments of FUSE, but to look toward the future and understand the major scientific drivers for the ultraviolet capabilities of the next generation fo space observatories. Invited speakers presented discussions based on measurements made by FUSE and other ultraviolet instruments, assessed their connection with measurements made with other techniques and, where appropriate, discussed the implications of low-z measurements for high-z phenomena. In addition to the oral presentations, many participants presented poster papers. The breadth of these presentation made it clear that much good science is still in progress with FUSE data and that these result will continue to have relevance in many scientific areas.

  2. Ultraviolet-radiation-curable paints

    Energy Technology Data Exchange (ETDEWEB)

    Grosset, A M; Su, W F.A.; Vanderglas, E

    1981-09-30

    In product finishing lines, ultraviolet radiation curing of paints on prefabricated structures could be more energy efficient than curing by natural gas fired ovens, and could eliminate solvent emission. Diffuse ultraviolet light can cure paints on three dimensional metal parts. In the uv curing process, the spectral output of radiation sources must complement the absorption spectra of pigments and photoactive agents. Photosensitive compounds, such as thioxanthones, can photoinitiate unsaturated resins, such as acrylated polyurethanes, by a free radical mechanism. Newly developed cationic photoinitiators, such as sulfonium or iodonium salts (the so-called onium salts) of complex metal halide anions, can be used in polymerization of epoxy paints by ultraviolet light radiation. One-coat enamels, topcoats, and primers have been developed which can be photoinitiated to produce hard, adherent films. This process has been tested in a laboratory scale unit by spray coating these materials on three-dimensional objects and passing them through a tunnel containing uv lamps.

  3. Ultraviolet spectrophotometry of three LINERs

    Science.gov (United States)

    Goodrich, R. W.; Keel, W. C.

    1986-01-01

    Three galaxies known to be LINERs were observed spectroscopically in the ultraviolet in an attempt to detect the presumed nonthermal continuum source thought to be the source of photoionization in the nuclei. NGC 4501 was found to be too faint for study with the IUE spectrographs, while NGC 5005 had an extended ultraviolet light profile. Comparison with the optical light profile of NGC 5005 indicates that the ultraviolet source is distributed spatially in the same manner as the optical starlight, probably indicating that the ultraviolet excess is due to a component of hot stars in the nucleus. These stars contribute detectable absorption features longward of 2500 A; together with optical data, the IUE spectra suggest a burst of star formation about 1 billion yr ago, with a lower rate continuing to produce a few OB stars. In NGC 4579, a point source contributing most of the ultraviolet excess is found that is much different than the optical light distribution. Furthermore, the ultraviolet to X-ray spectral index in NGC 4579 is 1.4, compatible with the UV to X-ray indices found for samples of Seyfert galaxies. This provides compelling evidence for the detection of the photoionizing continuum in NGC 4579 and draws the research fields of normal galaxies and active galactic nuclei closer together. The emission-line spectrum of NGC 4579 is compared with calculations from a photoionization code, CLOUDY, and several shock models. The photoionization code is found to give superior results, adding to the increasing weight of evidence that the LINER phenomenon is essentially a scaled-down version of the Seyfert phenomenon.

  4. Ultraviolet observations of AM Herculis

    International Nuclear Information System (INIS)

    Tanzi, E.G.; Treves, A.; Milan Univ.; Sandford, M.C.W.; Willis, A.J.; Wilson, R.

    1980-01-01

    Seven ultraviolet spectra (1100-3200 Angstroem) of AM Her were obtained with the low resolution spectrometer of the IUE satellite. Strong emission features appear superimposed on a well defined continuum which is well fitted by a Fsub(lambda) D lambda -2 law. The observations are compared with the expectations from models of the source. (orig.) 891 WL/orig. 892 HIS

  5. Ultraviolet light and cutaneous lupus

    NARCIS (Netherlands)

    Bijl, Marc; Kallenberg, Cees G. M.

    2006-01-01

    Exposure to ultraviolet (UV) light is one of the major factors known to trigger cutaneous disease activity in (systemic) lupus erythematosus patients. UV light, UVB in particular, is a potent inducer of apoptosis. Currently, disturbed clearance of apoptotic cells is one of the concepts explaining

  6. Comparative investigation of long-wave infrared generation based on ZnGeP{sub 2} and CdSe optical parametric oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Bao-Quan, Yao; Gang, Li; Guo-Li, Zhu; Pei-Bei, Meng; You-Lun, Ju; Wang Yue-Zhu, E-mail: yaobq08@hit.edu.cn [National Key Laboratory of Tunable Laser Technology Harbin Institute of Technology Harbin 150001 (China)

    2012-03-15

    Long-wave infrared (IR) generation based on type-II (o{yields}e+o) phase matching ZnGeP{sub 2} (ZGP) and CdSe optical parametric oscillators (OPOs) pumped by a 2.05 {mu}m Tm,Ho:GdVO{sub 4} laser is reported. The comparisons of the bire-fringent walk-off effect and the oscillation threshold between ZGP and CdSe OPOs are performed theoretically and experimentally. For the ZGP OPO, up to 419 mW output at 8.04 {mu}m is obtained at the 8 kHz pump pulse repetition frequency (PRF) with a slope efficiency of 7.6%. This ZGP OPO can be continuously tuned from 7.8 to 8.5 {mu}m. For the CdSe OPO, we demonstrate a 64 mW output at 8.9 {mu}m with a single crystal 28 mm in length. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  7. Rapid long-wave infrared laser-induced breakdown spectroscopy measurements using a mercury-cadmium-telluride linear array detection system.

    Science.gov (United States)

    Yang, Clayton S-C; Brown, Eiei; Kumi-Barimah, Eric; Hommerich, Uwe; Jin, Feng; Jia, Yingqing; Trivedi, Sudhir; D'souza, Arvind I; Decuir, Eric A; Wijewarnasuriya, Priyalal S; Samuels, Alan C

    2015-11-20

    In this work, we develop a mercury-cadmium-telluride linear array detection system that is capable of rapidly capturing (∼1-5  s) a broad spectrum of atomic and molecular laser-induced breakdown spectroscopy (LIBS) emissions in the long-wave infrared (LWIR) region (∼5.6-10  μm). Similar to the conventional UV-Vis LIBS, a broadband emission spectrum of condensed phase samples covering the whole 5.6-10 μm region can be acquired from just a single laser-induced microplasma or averaging a few single laser-induced microplasmas. Atomic and molecular signature emission spectra of solid inorganic and organic tablets and thin liquid films deposited on a rough asphalt surface are observed. This setup is capable of rapidly probing samples "as is" without the need of elaborate sample preparation and also offers the possibility of a simultaneous UV-Vis and LWIR LIBS measurement.

  8. Ultraviolet extensions of particle physics

    DEFF Research Database (Denmark)

    Berthier, Laure Gaëlle

    The discovery of the Higgs boson in 2012 at the Large Hadron Collider completed the Standard Model field content. Many questions though remain unanswered by the Standard Model triggering a search for new physics. New physics could manifest itself at the Large Hadron Collider by the discovery of new...... particles. However, the lack of new resonances might suggest that these new particles are still out of reach which leaves us with few options. Two possibilities are explored in this thesis. The first is to study precision measurements which might indicate new physics as small deviations from the Standard...... are expressed as power series with missing higher order terms. We also show how to connect ultraviolet models of new physics to the Standard Model effective field theory and calculate bounds on them using the Standard Model effective field theory fit results. Finally, we study a nonrelativistic ultraviolet...

  9. Ultraviolet divergences and supersymmetric theories

    International Nuclear Information System (INIS)

    Sagnotti, A.

    1984-09-01

    This article is closely related to the one by Ferrara in these same Proceedings. It deals with what is perhaps the most fascinating property of supersymmetric theories, their improved ultraviolet behavior. My aim here is to present a survey of the state of the art as of August, 1984, and a somewhat more detailed discussion of the breakdown of the superspace power-counting beyond N = 2 superfields. A method is also described for simplifying divergence calculations that uses the locality of subtracted Feynman integrals. 74 references

  10. Ultraviolet disinfection of potable water

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, R. L. [Metropolitan Water District of Southern California, Los Angeles, CA (United States)

    1990-06-15

    Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection.

  11. Ultraviolet disinfection of potable water

    International Nuclear Information System (INIS)

    Wolfe, R.L.

    1990-01-01

    Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection

  12. Ultraviolet divergences of Einstein gravity

    International Nuclear Information System (INIS)

    Goroff, M.H.

    1986-01-01

    The author discuss a two-loop calculation showing that the S matrix of Einstein's theory of gravity contains nonrenormalizable ultraviolet divergences in four dimension. The author discusses the calculation in both background field and normal field theory. The author describes a new method for dealing with ghost fields in gauge theories by combining them with suitable extensions of the gauge fields in higher dimensions. The author shows how using subtracted integrals in the calculation of higher loop graphs simplifies the calculation in the background field method by eliminating the need for mixed counterterms. Finally, the author makes some remarks about the implications of the result for supergravity theories

  13. Ultraviolet laser technology and applications

    CERN Document Server

    Elliott, David L

    1995-01-01

    Ultraviolet Laser Technology and Applications is a hands-on reference text that identifies the main areas of UV laser technology; describes how each is applied; offers clearly illustrated examples of UV opticalsystems applications; and includes technical data on optics, lasers, materials, and systems. This book is unique for its comprehensive, in-depth coverage. Each chapter deals with a different aspect of the subject, beginning with UV light itself; moving through the optics, sources, and systems; and concluding with detailed descriptions of applications in various fields.The text enables pr

  14. Dose modeling in ultraviolet phototherapy

    International Nuclear Information System (INIS)

    Grimes, David Robert; Robbins, Chris; O'Hare, Neil John

    2010-01-01

    Purpose: Ultraviolet phototherapy is widely used in the treatment of numerous skin conditions. This treatment is well established and largely beneficial to patients on both physical and psychological levels; however, overexposure to ultraviolet radiation (UVR) can have detrimental effects, such as erythemal responses and ocular damage in addition to the potentially carcinogenic nature of UVR. For these reasons, it is essential to control and quantify the radiation dose incident upon the patient to ensure that it is both biologically effective and has the minimal possible impact on the surrounding unaffected tissue. Methods: To date, there has been little work on dose modeling, and the output of artificial UVR sources is an area where research has been recommended. This work characterizes these sources by formalizing an approach from first principles and experimentally examining this model. Results: An implementation of a line source model is found to give impressive accuracy and quantifies the output radiation well. Conclusions: This method could potentially serve as a basis for a full computational dose model for quantifying patient dose.

  15. Evolution of solar ultraviolet luminosity

    International Nuclear Information System (INIS)

    Zahnle, K.J.; Walker, J.C.G.

    1982-01-01

    In view of the major role of the sun in defining the properties of planetary atmospheres, their evolution cannot be fully understood outside the context of an evolving sun. The ultraviolet radiation is especially interesting because of its strong interaction with planetary atmospheres. We use astronomical observation of stars that are analogous to the sun in order to reconstruct a tentative account of the evolution of solar UV luminosity. A wealth of evidence indicates that the young sun was a much more powerful source of energetic particles and radiation than it is today. While on the main sequence, solar activity has declined as an inverse power law of age (between t -5 and t/sup -1.2/) as a consequence of angular momentum loss to the solar wind. Recent IUE satellite observations of premain sequence stars suggest that before the sun reached the main sequence (at an age of about 50 m.y.), it may have emitted as much as 10 4 times as much ultraviolet radiation (γ<2000 A) than it does today. These results could impact our understanding of the photochemistry and escape of constituents of primordial planetary atmospheres

  16. Solar ultraviolet radiation effects on biological systems

    International Nuclear Information System (INIS)

    Diffey, B.L.

    1991-01-01

    This extensive review discusses the topic under the following headings: ultraviolet climatology, molecular and cellular ultraviolet photobiology (absorption, photoproducts, repair), effects of solar UVR on aquatic life (phyto and zooplankton), plants and humans. The section on human effects includes tanning, photo-aging, non-melanoma and melanoma skin cancers and the effects of solar UVR on the eye. (UK)

  17. Solar ultraviolet radiation effects on biological systems

    Energy Technology Data Exchange (ETDEWEB)

    Diffey, B.L. (Dryburn Hospital, Durham (UK). Regional Medical Physics Dept.)

    1991-03-01

    This extensive review discusses the topic under the following headings: ultraviolet climatology, molecular and cellular ultraviolet photobiology (absorption, photoproducts, repair), effects of solar UVR on aquatic life (phyto and zooplankton), plants and humans. The section on human effects includes tanning, photo-aging, non-melanoma and melanoma skin cancers and the effects of solar UVR on the eye. (UK).

  18. Ultraviolet safety assessments of insect light traps.

    Science.gov (United States)

    Sliney, David H; Gilbert, David W; Lyon, Terry

    2016-01-01

    Near-ultraviolet (UV-A: 315-400 nm), "black-light," electric lamps were invented in 1935 and ultraviolet insect light traps (ILTs) were introduced for use in agriculture around that time. Today ILTs are used indoors in several industries and in food-service as well as in outdoor settings. With recent interest in photobiological lamp safety, safety standards are being developed to test for potentially hazardous ultraviolet emissions. A variety of UV "Black-light" ILTs were measured at a range of distances to assess potential exposures. Realistic time-weighted human exposures are shown to be well below current guidelines for human exposure to ultraviolet radiation. These UV-A exposures would be far less than the typical UV-A exposure in the outdoor environment. Proposals are made for realistic ultraviolet safety standards for ILT products.

  19. The Ultraviolet Albedo of Ganymede

    Science.gov (United States)

    McGrath, Melissa; Hendrix, A.

    2013-10-01

    A large set of ultraviolet images of Ganymede have been acquired with the Hubble Space Telescope over the last 15 years. These images have been used almost exclusively to study Ganymede’s stunning auroral emissions (Feldman et al. 2000; Eviatar et al. 2001; McGrath et al. 2004; Saur et al. 2011; McGrath et al. 2013), and even the most basic information about Ganymede’s UV albedo has yet to be gleaned from these data. We will present a first-cut analysis of both disk-averaged and spatially-resolved UV albedos of Ganymede, with focus on the spatially-resolved Lyman-alpha albedo, which has never been considered previously for this satellite. Ganymede's visibly bright regions are known to be rich in water ice, while the visibly dark regions seem to be more carbonaceous (Carlson et al., 1996). At Lyman-alpha, these two species should also have very different albedo values. References Carlson, R. and 39 co-authors, Near-infrared spectroscopy and spectral mapping of Jupiter and the Galilean satellites: Results from Galileo’s initial orbit, Science, 274, 385-388, 1996. Eviatar, A., D. F. Strobel, B. C. Wolven, P. D. Feldman, M. A. McGrath, and D. J. Williams, Excitation of the Ganymede ultraviolet aurora, Astrophys. J, 555, 1013-1019, 2001. Feldman, P. D., M. A. McGrath, D. F. Strobel, H. W. Moos, K. D. Retherford, and B. C. Wolven, HST/STIS imaging of ultraviolet aurora on Ganymede, Astrophys. J, 535, 1085-1090, 2000. McGrath M. A., Lellouch E., Strobel D. F., Feldman P. D., Johnson R. E., Satellite Atmospheres, Chapter 19 in Jupiter: The Planet, Satellites and Magnetosphere, ed. F. Bagenal, T. Dowling, W. McKinnon, Cambridge University Press, 2004. McGrath M. A., Jia, Xianzhe; Retherford, Kurt; Feldman, Paul D.; Strobel, Darrell F.; Saur, Joachim, Aurora on Ganymede, J. Geophys. Res., doi: 10.1002/jgra.50122, 2013. Saur, J., S. Duling, S., L. Roth, P. D. Feldman, D. F. Strobel, K. D. Retherford, M. A. McGrath, A. Wennmacher, American Geophysical Union, Fall Meeting

  20. Hand protection from ultraviolet exposure

    International Nuclear Information System (INIS)

    Khazova, M.; O'Hagan, J.B.

    2006-01-01

    Full text of publication follows: A number of industrial applications and public services involve exposure to ultraviolet radiation (U.V.R.) from a variety of lamps and lasers, for example, in forensic examination, biological trans-illuminators, dentistry, laser material processing, microelectronics, etc. The proposed European Union Directive on Optical Radiation would place specific requirements on employers to provide adequate safety measures to reduce exposure to U.V.R., including gloves for hand protection. The selection of gloves should be based on a risk assessment and on the performance characteristics of the gloves for the task. However, current International and national standards do not describe evaluation procedures of disposable gloves for hand protection against non-ionising radiation. A methodology for assessment of the UV protection level for disposable gloves and a simple measurement protocol are proposed, based on a common approach with UV protection by clothing and sunscreens. Glove Ultraviolet Protection Factor is defined as a time-scale increase in exposure permitted for the hand protected by a glove with respect to an unprotected hand. However, the wide variety of U.V.R. sources and the real-life conditions of glove use (stretching and wetting the surface by liquids) bring substantial challenges to the assessment method. Our study of ∼ 50 samples of widely used disposable gloves made of different materials (nitrile, vinyl, latex and chloroprene) showed that for all tested gloves a change in U.V.R. attenuation with stretching is characteristic for the type of glove material and can be included as a scaling factor in the definition of U.V.R. protection. Glove material has a bigger effect on U.V.R. protection level than variations in the glove thickness or its colour. The following approaches are suggested to overcome the problem of variable U.V.R. sources: - Worst case scenario minimal protection level, most restrictive case - Application

  1. Hand protection from ultraviolet exposure

    Energy Technology Data Exchange (ETDEWEB)

    Khazova, M.; O' Hagan, J.B. [Health Protection Agency, Radiation Protection Division, Chilton, Did cot (United Kingdom)

    2006-07-01

    Full text of publication follows: A number of industrial applications and public services involve exposure to ultraviolet radiation (U.V.R.) from a variety of lamps and lasers, for example, in forensic examination, biological trans-illuminators, dentistry, laser material processing, microelectronics, etc. The proposed European Union Directive on Optical Radiation would place specific requirements on employers to provide adequate safety measures to reduce exposure to U.V.R., including gloves for hand protection. The selection of gloves should be based on a risk assessment and on the performance characteristics of the gloves for the task. However, current International and national standards do not describe evaluation procedures of disposable gloves for hand protection against non-ionising radiation. A methodology for assessment of the UV protection level for disposable gloves and a simple measurement protocol are proposed, based on a common approach with UV protection by clothing and sunscreens. Glove Ultraviolet Protection Factor is defined as a time-scale increase in exposure permitted for the hand protected by a glove with respect to an unprotected hand. However, the wide variety of U.V.R. sources and the real-life conditions of glove use (stretching and wetting the surface by liquids) bring substantial challenges to the assessment method. Our study of {approx} 50 samples of widely used disposable gloves made of different materials (nitrile, vinyl, latex and chloroprene) showed that for all tested gloves a change in U.V.R. attenuation with stretching is characteristic for the type of glove material and can be included as a scaling factor in the definition of U.V.R. protection. Glove material has a bigger effect on U.V.R. protection level than variations in the glove thickness or its colour. The following approaches are suggested to overcome the problem of variable U.V.R. sources: - Worst case scenario minimal protection level, most restrictive case - Application

  2. Galactic Astronomy in the Ultraviolet

    Science.gov (United States)

    Rastorguev, A. S.; Sachkov, M. E.; Zabolotskikh, M. V.

    2017-12-01

    We propose a number of prospective observational programs for the ultraviolet space observatory WSO-UV, which seem to be of great importance to modern galactic astronomy. The programs include the search for binary Cepheids; the search and detailed photometric study and the analysis of radial distribution of UV-bright stars in globular clusters ("blue stragglers", blue horizontal-branch stars, RR Lyrae variables, white dwarfs, and stars with UV excesses); the investigation of stellar content and kinematics of young open clusters and associations; the study of spectral energy distribution in hot stars, including calculation of the extinction curves in the UV, optical and NIR; and accurate definition of the relations between the UV-colors and effective temperature. The high angular resolution of the observatory allows accurate astrometric measurements of stellar proper motions and their kinematic analysis.

  3. Additive effects of ultraviolet radiation

    International Nuclear Information System (INIS)

    Cullen, A.P.

    1980-01-01

    A xenon-mercury high pressure lamp and a double monochromator were used to produce ultraviolet (uv) radiation at 295 nm. Pigmented rabbit eyes were irradiated and evaluated by slitlamp biomicroscopy. Corneal threshold (Hc) was 0.05 J.cm-2 and lens threshold (hL) was 0.75 J.cm-2. Other eyes were irradiated with 2 Hc and evaluated from 4 to 24 h at 4 h intervals. Corneal damage was only greater than that expected from a single Hc exposure if the separation between the two Hc exposures did not exceed 8 h. The most repeatable and reliable corneal response to these levels of uv was the development of corneal epithelial granules

  4. Ultraviolet Spectrophotometry of VV Cephei

    Directory of Open Access Journals (Sweden)

    Young Woon Kang

    1992-06-01

    Full Text Available The IUE archival spectra of VV Cephei were collected to investigate the eclipse nature in the ultraviolet. The temperature of the B star has been determined, as approximately 30000K, based on the flux distributions during egress. Light curves of VV Cephei were reduced from the spectrophotometry of the IUE archival spectra. Three light curves at the center wavelengths of 3250 Å, 2550 Å and 2850 Å have been analyzed by the modified Wilson and Devinney light curve program. The radii of the B star and M star were deduced to 0.05 and 0.22 of unit separation, respectively. The UV light curves show an evidence that the light was attenuated by the highly opaque atomsphere of the M star.

  5. Ultraviolet, Visible, and Fluorescence Spectroscopy

    Science.gov (United States)

    Penner, Michael H.

    Spectroscopy in the ultraviolet-visible (UV-Vis) range is one of the most commonly encountered laboratory techniques in food analysis. Diverse examples, such as the quantification of macrocomponents (total carbohydrate by the phenol-sulfuric acid method), quantification of microcomponents, (thiamin by the thiochrome fluorometric procedure), estimates of rancidity (lipid oxidation status by the thiobarbituric acid test), and surveillance testing (enzyme-linked immunoassays), are presented in this text. In each of these cases, the analytical signal for which the assay is based is either the emission or absorption of radiation in the UV-Vis range. This signal may be inherent in the analyte, such as the absorbance of radiation in the visible range by pigments, or a result of a chemical reaction involving the analyte, such as the colorimetric copper-based Lowry method for the analysis of soluble protein.

  6. The mutagenic effect of near ultraviolet light on the nvs strains of Aspergillus nidulans in the presence of 8-metoxypsoralen or angelicin

    International Nuclear Information System (INIS)

    Muronets, E.M.; Kovtunenko, L.V.; Kameneva, S.V.

    1980-01-01

    The mutual mutagenic effect of long-wave ultraviolet radiation (EUV) with angelicin which forms monoadducts in DNA and 8-metoxypsoralen (8 MOP) which forms monoadducts and joints, on conidia of uvs- and uvs+ strains of Aspergillus nidulans, is studied. The two types of interaction are shown to induce mutations intensively. Mutation induction with angelicin shows the role of psoralen pyrimidine monoadducts in mutagenesis. The technique of fractionated EUV radiation and studying the effect of monoadduct repair effectiveness on mutation output permits to prove that interthread DNA joints induced by 8-MOP+EUV are also highly mutagenous. The products of UVS/2, 20b, 26 genes which take part in the excision of DNA damages do not take part in the formation of mutations induced in aspergil by furocoumarine + EUV. The products of uvs 19, 20a genes which take part in the postreplicative DNA reduction are neccessary for the repair of premutation damages induced by furocoumarine + EUV

  7. Stratospheric ozone, ultraviolet radiation and climate change

    International Nuclear Information System (INIS)

    Boucher, O.

    2008-01-01

    It is well known that an overexposure to ultraviolet radiation is associated with a number of health risks such as an increased risk of cataracts and skin cancers. At a time when climate change is often blamed for all our environmental problems, what is the latest news about the stratospheric ozone layer and other factors controlling ultraviolet radiation at the surface of the Earth? Will the expected changes in the chemical composition of the atmosphere and changes in our climate increase or decrease the risk for skin cancer? This article investigates the role of the various factors influencing ultraviolet radiation and presents the latest knowledge on the subject. (author)

  8. Ultraviolet safety assessments of insect light traps

    OpenAIRE

    Sliney, David H.; Gilbert, David W.; Lyon, Terry

    2016-01-01

    ABSTRACT Near-ultraviolet (UV-A: 315?400?nm), ?black-light,? electric lamps were invented in 1935 and ultraviolet insect light traps (ILTs) were introduced for use in agriculture around that time. Today ILTs are used indoors in several industries and in food-service as well as in outdoor settings. With recent interest in photobiological lamp safety, safety standards are being developed to test for potentially hazardous ultraviolet emissions. A variety of UV ?Black-light? ILTs were measured at...

  9. Some aspects of vacuum ultraviolet radiation physics

    CERN Document Server

    Damany, Nicole; Vodar, Boris

    2013-01-01

    Some Aspects of Vacuum Ultraviolet Radiation Physics presents some data on the state of research in vacuum ultraviolet radiation in association with areas of physics. Organized into four parts, this book begins by elucidating the optical properties of solids in the vacuum ultraviolet region (v.u.v.), particularly the specific methods of determination of optical constants in v.u.v., the properties of metals, and those of ionic insulators. Part II deals with molecular spectroscopy, with emphasis on the spectra of diatomic and simple polyatomic molecules, paraffins, and condensed phases. Part III

  10. Stimulation of hair cells with ultraviolet light

    Science.gov (United States)

    Azimzadeh, Julien B.; Fabella, Brian A.; Hudspeth, A. J.

    2018-05-01

    Hair bundles are specialized organelles that transduce mechanical inputs into electrical outputs. To activate hair cells, physiologists have resorted to mechanical methods of hair-bundle stimulation. Here we describe a new method of hair-bundle stimulation, irradiation with ultraviolet light. A hair bundle illuminated by ultraviolet light rapidly moves towards its tall edge, a motion typically associated with excitatory stimulation. The motion disappears upon tip-link rupture and is associated with the opening of mechanotransduction channels. Hair bundles can be induced to move sinusoidally with oscillatory modulation of the stimulation power. We discuss the implications of ultraviolet stimulation as a novel hair-bundle stimulus.

  11. Global scale variability of the mineral dust long-wave refractive index: a new dataset of in situ measurements for climate modeling and remote sensing

    Science.gov (United States)

    Di Biagio, Claudia; Formenti, Paola; Balkanski, Yves; Caponi, Lorenzo; Cazaunau, Mathieu; Pangui, Edouard; Journet, Emilie; Nowak, Sophie; Caquineau, Sandrine; Andreae, Meinrat O.; Kandler, Konrad; Saeed, Thuraya; Piketh, Stuart; Seibert, David; Williams, Earle; Doussin, Jean-François

    2017-02-01

    Modeling the interaction of dust with long-wave (LW) radiation is still a challenge because of the scarcity of information on the complex refractive index of dust from different source regions. In particular, little is known about the variability of the refractive index as a function of the dust mineralogical composition, which depends on the specific emission source, and its size distribution, which is modified during transport. As a consequence, to date, climate models and remote sensing retrievals generally use a spatially invariant and time-constant value for the dust LW refractive index. In this paper, the variability of the mineral dust LW refractive index as a function of its mineralogical composition and size distribution is explored by in situ measurements in a large smog chamber. Mineral dust aerosols were generated from 19 natural soils from 8 regions: northern Africa, the Sahel, eastern Africa and the Middle East, eastern Asia, North and South America, southern Africa, and Australia. Soil samples were selected from a total of 137 available samples in order to represent the diversity of sources from arid and semi-arid areas worldwide and to account for the heterogeneity of the soil composition at the global scale. Aerosol samples generated from soils were re-suspended in the chamber, where their LW extinction spectra (3-15 µm), size distribution, and mineralogical composition were measured. The generated aerosol exhibits a realistic size distribution and mineralogy, including both the sub- and super-micron fractions, and represents in typical atmospheric proportions the main LW-active minerals, such as clays, quartz, and calcite. The complex refractive index of the aerosol is obtained by an optical inversion based upon the measured extinction spectrum and size distribution. Results from the present study show that the imaginary LW refractive index (k) of dust varies greatly both in magnitude and spectral shape from sample to sample, reflecting the

  12. Photodetector of ultra-violet radiation

    International Nuclear Information System (INIS)

    Dorogan, V.; Vieru, T.; Coseac, V.; Chirita, F.

    1999-01-01

    The invention relates to photodetectors on the semiconductors base, in particular, to photodetectors of ultra-violet radiation and can be used in the optoelectronics systems for determining the intensity and dose of ultraviolet radiation emitted by the Sun and other sources. In the structure of the photodetector of ultraviolet radiation with a superficial potential barrier formed of semiconductors A 3 B 5 with the prohibited power width Eg 1 , solid solutions thereof with the prohibited power width Eg 2 and SnO 2 or ITO, in the semiconductors A 3 B 5 at a surface distance less than the absorption length of the visible radiation it is formed an isotype heterojunction between the semiconductors A 3 B 5 and solid solutions thereof with the prohibited power width Eg 2 > Eg 1 . The technical result consists in manufacturing of a photodetector sensitive solely to the ultraviolet radiation

  13. Outdoor ultraviolet exposure of children and adolescents

    International Nuclear Information System (INIS)

    Diffey, B.L.; Gibson, C.J.

    1996-01-01

    The weekday and weekend outdoor ultraviolet exposure of young people from primary and secondary schools in three geographically distinct regions of England was determined over a 3-month period in summer. Ultraviolet exposure was measured using personal film badges worn by each young person and time spent outdoors, in hourly intervals, assessed using exposure records. In each area a class of 9-10 year-old children from a primary school and a class of 14-15-year-old adolescents from a secondary school took part, giving a total of 180 subjects. We found that primary school children received higher outdoor ultraviolet exposure than young people in secondary schools, and geographical differences in exposure could not be accounted for solely by differences in ambient ultraviolet. There was little difference between the exposure of males and females. Children and adolescents did not behave as homogeneous groups with regard to exposure. (Author)

  14. Ultraviolet light - nature's own disinfection process

    Energy Technology Data Exchange (ETDEWEB)

    Munkeberg, T [Thorolf Gregersen a/s, Oslo (Norway)

    1978-05-18

    Ultraviolet radiation from the sun is the means by which natural pollution products, as well as much of the smaller amount of pollution products produced by man, are converted and returned to the cycle of nature. Artificial ultraviolet radiation offers an optimum method for the disinfection of drinking water and can be used in the long term without undesireable effects on man or the enviromment. There is no evidence that ultraviolet irradiation leads to radiation resistant mutations of bacteria. The geometrical arrangement of ultraviolet disinfection units is described and the capacities of typical units is mentioned as being 600-800 m/sup 3/ /hr, though there is no reason why this should not be increased.

  15. Ultraviolet light - nature's own disinfection process

    International Nuclear Information System (INIS)

    Munkeberg, T.

    1978-01-01

    Ultraviolet radiation from the sun is the means by which natural pollution products, as well as much of the smaller amount of pollution products produced by man, are converted and returned to the cycle of nature. Artificial ultraviolet radiation offers an optimum method for the disinfection of drinking water and can be used in the long term without undesireable effects on man or the enviromment. There is no evidence that ultraviolet irradiation leads to radiation resistant mutations of bacteria. The geometrical arrangement of ultraviolet disinfection units is described and the capacities of typical units is mentioned as being 600-800 m 3 /hr, though there is no reason why this should not be increased. (JIW)

  16. Inactivation of mitochondrial ATPase by ultraviolet light

    International Nuclear Information System (INIS)

    Chavez, E.; Cuellar, A.

    1984-01-01

    The present work describes experiments that show that far-ultraviolet irradiation induce the inhibition of ATPase activity in both membrane-bound and soluble F1. It was also found that ultraviolet light promotes the release of tightly bound adenine nucleotides from F1-ATPase. Experiments carried out with submitochondrial particles indicate that succinate partially protects against these effects of ultraviolet light. Titration of sulfhydryl groups in both irradiated submitochondrial particles and soluble F1-ATPase indicates that a conformational change induced by photochemical modifications of amino acid residues appears involved in the inactivation of the enzyme. Finally, experiments are described which show that the tyrosine residue located in the active site of F1-ATPase is modified by ultraviolet irradiation

  17. Stability and Transient Effects in Ultraviolet Filaments

    National Research Council Canada - National Science Library

    Niday, Thomas

    2004-01-01

    .... Much of the work in this field has been done with infrared pulses; however, it has been proposed that ultraviolet pulses have the advantage that longer pulse lengths can be used, thereby delivering more energy...

  18. PMMA Wettability Caused by Ultraviolet Radiation

    OpenAIRE

    Dehtjars, J; Lancere, L; Poļaka, N; Soudnikovich, A; Tjuļkins, F; Valters, V

    2010-01-01

    The article is targeted to explore ultraviolet radiation (UV) influence on PMMAf or eye prostheses. UV beingt he Sun lightc omponenta nd could effect PMMA surface that in turn contributesi nteractionw ith tear. PMMA wettabilityw as poweredb y UV.

  19. Ultraviolet treatment on high performance filaments

    International Nuclear Information System (INIS)

    Gu Huang

    2005-01-01

    Quartz, Kevlar, carbon, and glass filaments were irradiated by ultraviolet ray with various periods. Tensile strength of the treated fibres was tested and analyzed, and the outward appearance of the treated filaments was shown

  20. Vacuum-Ultraviolet Photovoltaic Detector.

    Science.gov (United States)

    Zheng, Wei; Lin, Richeng; Ran, Junxue; Zhang, Zhaojun; Ji, Xu; Huang, Feng

    2018-01-23

    Over the past two decades, solar- and astrophysicists and material scientists have been researching and developing new-generation semiconductor-based vacuum ultraviolet (VUV) detectors with low power consumption and small size for replacing traditional heavy and high-energy-consuming microchannel-detection systems, to study the formation and evolution of stars. However, the most desirable semiconductor-based VUV photovoltaic detector capable of achieving zero power consumption has not yet been achieved. With high-crystallinity multistep epitaxial grown AlN as a VUV-absorbing layer for photogenerated carriers and p-type graphene (with unexpected VUV transmittance >96%) as a transparent electrode to collect excited holes, we constructed a heterojunction device with photovoltaic detection for VUV light. The device exhibits an encouraging VUV photoresponse, high external quantum efficiency (EQE) and extremely fast tempera response (80 ns, 10 4 -10 6 times faster than that of the currently reported VUV photoconductive devices). This work has provided an idea for developing zero power consumption and integrated VUV photovoltaic detectors with ultrafast and high-sensitivity VUV detection capability, which not only allows future spacecraft to operate with longer service time and lower launching cost but also ensures an ultrafast evolution of interstellar objects.

  1. Human exposure to ultraviolet radiation

    International Nuclear Information System (INIS)

    Bernhardt, J.H.; Matthes, R.

    1987-01-01

    Ultraviolet radiation is that part of the electromagnetic spectrum located between the softest ionizing radiation and visible radiation. The lower limit of 100 nm is equivalent to photon energies of 12.4 eV, which corresponds approximately to the limit for the production of ionization in biologically important materials. A historical subdividing of the UV-region takes some of the biological effects into account. In this arrangement the range 400-315 nm, the so-called black light region, is called UV-A. In this wavelength region, fluorescence can be induced in many substances. UV-B covers the range 315-280 nm (the skin erythemal region). Most of the biologically active and potentially harmful UV from the sun reaching the surface of the earth is part of this spectral region. UV-C includes the radiation of wavelengths less than 280 nm (the germicidal region). It should be noted that this classification is somewhat arbitrary, and today it is more usual to evaluate the biological effectiveness of the whole UV-range from 200 to 400 nm

  2. Unintentional exposure to ultraviolet radiation

    International Nuclear Information System (INIS)

    Sliney, D.H.

    1987-01-01

    To evaluate the risks from unintentional exposure to ultraviolet radiation (UVR), and to consider hazard control regulation, one must face first the problem of their state of scientific knowledge and the public's perception of UVR. Few people in the general public would question the health benefits of sunlight. Many flock to the beaches each summer to develop a healthy tan. Since the 1920's scientists have recognized that most of the benefits--and risks--of sunlight exposure result from the UVR present in sunlight. Dermatologists warn sunbathers to avoid exposure or protect themselves against the intense midday UVR or risk skin cancer. A growing number of scientists warn of hazards to the eye if UVR--perhaps even shorter visible wavelengths--are not filtered by lenses. In addition to any intentional exposure for health or cosmetic purposes, many people are also exposed to UVR without being aware of it or without their intent to be exposed. Outdoor workers are exposed to sunlight, many industrial workers (e.g., welders) are exposed to UVR from arc sources, some UVR penetrates clothing, and people indoors are exposed to UVR from artificial lighting

  3. Dermal damage from ultraviolet radiation

    International Nuclear Information System (INIS)

    Kligman, L.H.

    1988-01-01

    Ultraviolet (UV) radiation is increasingly recognized as the cause of a vast number of changes in the skin of humans and animals. These include alterations at the molecular, cellular, tissue and systematic levels. In the recent past, much has been learned about the immediate effects in skin of acute UV exposure (i.e. sunburn) with its epidermal cell death, inflammation and vasolidation. With chronic exposure, many of the clinical and histologic effects can be seen only after decades. Visually, these are hyper- and hypopigmented macules, dry scaly, wrinkled skin with a variety of benign, pre-malignant and malignant neoplasms. All epidermal in origin, they lead, inexorably in humans, to the appearance the authors described as photo-aged. Underlying many of these visible manifestations are drastic changes in the dermis. These relate chiefly to destruction of mature collagen, with a compensatory overproduction of reticulin fibers, hyperplasia of elastic fibers eventuating in elastosis, increased levels of the glycosaminoglycans (GAGs) comprising the ground substance and changes in the microvasculature. First described in actinically damaged humans, systematic investigation required an animal model

  4. Masks for extreme ultraviolet lithography

    International Nuclear Information System (INIS)

    Cardinale, G; Goldsmith, J; Kearney, P A; Larson, C; Moore, C E; Prisbrey, S; Tong, W; Vernon, S P; Weber, F; Yan, P-Y.

    1998-01-01

    In extreme ultraviolet lithography (EUVL), the technology specific requirements on the mask are a direct consequence of the utilization of radiation in the spectral region between 10 and 15 nm. At these wavelengths, all condensed materials are highly absorbing and efficient radiation transport mandates the use of all-reflective optical systems. Reflectivity is achieved with resonant, wavelength-matched multilayer (ML) coatings on all of the optical surfaces - including the mask. The EUV mask has a unique architecture - it consists of a substrate with a highly reflective ML coating (the mask blank) that is subsequently over-coated with a patterned absorber layer (the mask). Particulate contamination on the EUVL mask surface, errors in absorber definition and defects in the ML coating all have the potential to print in the lithographic process. While highly developed technologies exist for repair of the absorber layer, no viable strategy for the repair of ML coating defects has been identified. In this paper the state-of-the-art in ML deposition technology, optical inspection of EUVL mask blank defects and candidate absorber patterning approaches are reviewed

  5. Ultraviolet complete dark energy model

    Science.gov (United States)

    Narain, Gaurav; Li, Tianjun

    2018-04-01

    We consider a local phenomenological model to explain a nonlocal gravity scenario which has been proposed to address dark energy issues. This nonlocal gravity action has been seen to fit the data as well as Λ -CDM and therefore demands a more fundamental local treatment. The induced gravity model coupled with higher-derivative gravity is exploited for this proposal, as this perturbatively renormalizable model has a well-defined ultraviolet (UV) description where ghosts are evaded. We consider a generalized version of this model where we consider two coupled scalar fields and their nonminimal coupling with gravity. In this simple model, one of the scalar field acquires a vacuum expectation value (VEV), thereby inducing a mass for one of the scalar fields and generating Newton's constant. The induced mass however is seen to be always above the running energy scale thereby leading to its decoupling. The residual theory after decoupling becomes a platform for driving the accelerated expansion under certain conditions. Integrating out the residual scalar generates a nonlocal gravity action. The leading term of which is the nonlocal gravity action used to fit the data of dark energy.

  6. Influence of near ultraviolet light on microorganisms

    International Nuclear Information System (INIS)

    Fraikin, G.Y.A.; Rubin, L.B.

    1980-01-01

    Our results and the recent literature data on the biological action of near ultraviolet light (300-380 nm) are examined in the review. Factual material is presented on the principles governing the manifestation of the following effects of near ultraviolet light in microorganisms: inactivation, delayed growth, photoreactivation, photoprotection, photoinduced sporulation (in fungi), and carotene synthesis. The mature and possible mechanisms of the effects examined are discussed

  7. Ultraviolet colors of subdwarf O stars

    International Nuclear Information System (INIS)

    Wesselius, P.R.

    1978-01-01

    The group of subdwarf O stars consisting of field stars and some central stars of old planetary nebulae does occupy an interesting place in the HR diagram. Greenstein and Sargent (1974) have tried to establish this place, and conclude that especially the hottest ones need ultraviolet data to improve the values of effective temperature and absolute luminosity. The author therefore observed some twenty sdO stars in the far ultraviolet using the spectrophotometer in the Netherlands' satellite ANS. (Auth.)

  8. Extreme Ultraviolet Explorer Bright Source List

    Science.gov (United States)

    Malina, Roger F.; Marshall, Herman L.; Antia, Behram; Christian, Carol A.; Dobson, Carl A.; Finley, David S.; Fruscione, Antonella; Girouard, Forrest R.; Hawkins, Isabel; Jelinsky, Patrick

    1994-01-01

    Initial results from the analysis of the Extreme Ultraviolet Explorer (EUVE) all-sky survey (58-740 A) and deep survey (67-364 A) are presented through the EUVE Bright Source List (BSL). The BSL contains 356 confirmed extreme ultraviolet (EUV) point sources with supporting information, including positions, observed EUV count rates, and the identification of possible optical counterparts. One-hundred twenty-six sources have been detected longward of 200 A.

  9. Ultraviolet photoelectron spectroscopy of transient species

    International Nuclear Information System (INIS)

    Leeuw, D.M. de.

    1979-01-01

    Transient species are studied in the isolation of the gas phase using ultraviolet photoelectron spectroscopy (PES). A description of the equipment used and a discussion of some theoretical topics, which play a role in the interpretation of PE spectra, are given. Koopmans' theorem, Hartree-Fock-Slater (HFS) calculations and the sum rule are discussed. A versatile ultraviolet PE spectrometer, designed specifically for this purpose, has been built and the construction and performance of this instrument are described. (Auth.)

  10. Ultraviolet Behavior of N = 8 Supergravity

    International Nuclear Information System (INIS)

    Dixon, Lance J.

    2010-01-01

    In these lectures the author describes the remarkable ultraviolet behavior of N = 8 supergravity, which through four loops is no worse than that of N = 4 super-Yang-Mills theory (a finite theory). I also explain the computational tools that allow multi-loop amplitudes to be evaluated in this theory - the KLT relations and the unitarity method - and sketch how ultraviolet divergences are extracted from the amplitudes.

  11. Pharmacokinetic and biopharmaceutic aspects of some psoralen derivatives used in dermatology

    International Nuclear Information System (INIS)

    Stolk, L.M.L.

    1982-01-01

    In the present thesis the pharmacokinetic and biopharmaceutic properties of some psoralen derivatives, that are used in photochemotherapy of dermatological diseases like vitiligo and psoriasis, are studied. Photochemotherapy is a combination of oral administration of one of the psoralen derivatives, 8-methoxypsoralen (8-MOP), 5-methoxypsoralen (5-MOP) or 4, 5', 8-trimethylpsoralen (TMP), and irradiation with long wave ultraviolet light, U.V.-A (320-400 nm), two hours later. This treatment is commonly called PUVA (Psoralen-UV-A). The purpose of the investigation was to develop an 8-MOP dosage form with a fast and reproducible absorption. Various dosage forms of 8-MOP were administered to volunteers and patients and 8-MOP concentrations in body fluids determined. Also the pharmacokinetic properties of 5-MOP and TMP were investigated in a pilot study. (Auth.)

  12. Ultraviolet resources over Northern Eurasia.

    Science.gov (United States)

    Chubarova, Natalia; Zhdanova, Yekaterina

    2013-10-05

    We propose a new climatology of UV resources over Northern Eurasia, which includes the assessments of both detrimental (erythema) and positive (vitamin D synthesis) effects of ultraviolet radiation on human health. The UV resources are defined by using several classes and subclasses - UV deficiency, UV optimum, and UV excess - for 6 different skin types. To better quantifying the vitamin D irradiance threshold we accounted for an open body fraction S as a function of effective air temperature. The spatial and temporal distribution of UV resources was estimated by radiative transfer (RT) modeling (8 stream DISORT RT code) with 1×1° grid and monthly resolution. For this purpose special datasets of main input geophysical parameters (total ozone content, aerosol characteristics, surface UV albedo, UV cloud modification factor) have been created over the territory of Northern Eurasia. The new approaches were used to retrieve aerosol parameters and cloud modification factor in the UV spectral region. As a result, the UV resources were obtained for clear-sky and mean cloudy conditions for different skin types. We show that the distribution of UV deficiency, UV optimum and UV excess is regulated by various geophysical parameters (mainly, total ozone, cloudiness and open body fraction) and can significantly deviate from latitudinal dependence. We also show that the UV optimum conditions can be simultaneously observed for people with different skin types (for example, for 4-5 skin types at the same time in spring over Western Europe). These UV optimum conditions for different skin types occupy a much larger territory over Europe than that over Asia. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Ultraviolet Spectroscopy of Asteroid(4) Vesta

    Science.gov (United States)

    Li, Jian-Yang; Bodewits, Dennis; Feaga, Lori M.; Landsman, Wayne; A'Hearn, Michael F.; Mutchler, Max J.; Russell, Christopher T.; McFadden, Lucy A.; Raymond, Carol A.

    2011-01-01

    We report a comprehensive review of the UV-visible spectrum and rotational lightcurve of Vesta combining new observations by Hubble Space Telescope and Swift with archival International Ultraviolet Explorer observations. The geometric albedos of Vesta from 220 nm to 953 nm arc derived by carefully comparing these observations from various instruments at different times and observing geometries. Vesta has a rotationally averaged geometric albedo of 0.09 at 250 nm, 0.14 at 300 nm, 0.26 at 373 nm, 0.38 at 673 nm, and 0.30 at 950 nm. The linear spectral slope in the ultraviolet displays a sharp minimum ncar sub-Earth longitude of 20deg, and maximum in the eastern hemisphere. This is completely consistent with the distribution of the spectral slope in the visible wavelength. The uncertainty of the measurement in the ultraviolet is approx.20%, and in the visible wavelengths better than 10%. The amplitude of Vesta's rotational lightcurves is approx.10% throughout the range of wavelengths we observed, but is smaller at 950 nm (approx.6%) ncar the 1-micron mafic band center. Contrary to earlier reports, we found no evidence for any difference between the phasing of the ultraviolet and visible/ncar-infrared lightcurves with respect to sub-Earth longitude. Vesta's average spectrum between 220 and 950 nm can well be described by measured reflectance spectra of fine particle howardite-like materials of basaltic achondrite meteorites. Combining this with the in-phase behavior of the ultraviolet, visible. and ncar-infrared lightcurves, and the spectral slopes with respect to the rotational phase, we conclude that there is no global ultraviolet/visible reversal on Vesta. Consequently, this implies lack of global space weathering on Vesta. Keyword,: Asteroid Vesta; Spectrophotometry; Spectroscopy; Ultraviolet observations; Hubble Space Telescope observations

  14. Ultraviolet radiation therapy and UVR dose models

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, David Robert, E-mail: davidrobert.grimes@oncology.ox.ac.uk [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland and Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratory, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ (United Kingdom)

    2015-01-15

    Ultraviolet radiation (UVR) has been an effective treatment for a number of chronic skin disorders, and its ability to alleviate these conditions has been well documented. Although nonionizing, exposure to ultraviolet (UV) radiation is still damaging to deoxyribonucleic acid integrity, and has a number of unpleasant side effects ranging from erythema (sunburn) to carcinogenesis. As the conditions treated with this therapy tend to be chronic, exposures are repeated and can be high, increasing the lifetime probability of an adverse event or mutagenic effect. Despite the potential detrimental effects, quantitative ultraviolet dosimetry for phototherapy is an underdeveloped area and better dosimetry would allow clinicians to maximize biological effect whilst minimizing the repercussions of overexposure. This review gives a history and insight into the current state of UVR phototherapy, including an overview of biological effects of UVR, a discussion of UVR production, illness treated by this modality, cabin design and the clinical implementation of phototherapy, as well as clinical dose estimation techniques. Several dose models for ultraviolet phototherapy are also examined, and the need for an accurate computational dose estimation method in ultraviolet phototherapy is discussed.

  15. Ultraviolet radiation therapy and UVR dose models

    International Nuclear Information System (INIS)

    Grimes, David Robert

    2015-01-01

    Ultraviolet radiation (UVR) has been an effective treatment for a number of chronic skin disorders, and its ability to alleviate these conditions has been well documented. Although nonionizing, exposure to ultraviolet (UV) radiation is still damaging to deoxyribonucleic acid integrity, and has a number of unpleasant side effects ranging from erythema (sunburn) to carcinogenesis. As the conditions treated with this therapy tend to be chronic, exposures are repeated and can be high, increasing the lifetime probability of an adverse event or mutagenic effect. Despite the potential detrimental effects, quantitative ultraviolet dosimetry for phototherapy is an underdeveloped area and better dosimetry would allow clinicians to maximize biological effect whilst minimizing the repercussions of overexposure. This review gives a history and insight into the current state of UVR phototherapy, including an overview of biological effects of UVR, a discussion of UVR production, illness treated by this modality, cabin design and the clinical implementation of phototherapy, as well as clinical dose estimation techniques. Several dose models for ultraviolet phototherapy are also examined, and the need for an accurate computational dose estimation method in ultraviolet phototherapy is discussed

  16. Solar ultraviolet irradiance variations: a review

    International Nuclear Information System (INIS)

    Lean, J.

    1987-01-01

    Despite the geophysical importance of solar ultraviolet radiation, specific aspects of its temporal variations have not yet been adequately determined experimentally, nor are the mechanisms for the variability completely understood. Satellite observations have verified the reality of solar ultraviolet irradiance variations over time scales of days and months, and model calculations have confirmed the association of these short-term variations with the evolution and rotation of regions of enhanced magnetic activity on the solar disc. However, neither rocket nor satellite measurements have yet been made with sufficient accuracy and regularity to establish unequivocally the nature of the variability over the longer time of the 11-year solar cycle. The comparative importance for the long-term variations of local regions of enhanced magnetic activity and global scale activity perturbations is still being investigated. Solar ultraviolet irradiance variations over both short and long time scales are reviewed, with emphasis on their connection to solar magnetic activity. Correlations with ground-based measures of solar variability are examined because of the importance of the ground-based observations as historical proxies of ultraviolet irradiance variations. Current problems in understanding solar ultraviolet irradiance variations are discussed, and the measurements planned for solar cycle 22, which may resolve these problems, are briefly described. copyright American Geophysical Union 1987

  17. Mutagenesis of Trichoderma Viride by Ultraviolet and Plasma

    International Nuclear Information System (INIS)

    Yao Risheng; Li Manman; Deng Shengsong; Hu Huajia; Wang Huai; Li Fenghe

    2012-01-01

    Considering the importance of a microbial strain capable of increased cellulase production, a mutant strain UP4 of Trichoderma viride was developed by ultraviolet (UV) and plasma mutation. The mutant produced a 21.0 IU/mL FPase which was 98.1% higher than that of the parent strain Trichoderma viride ZY-1. In addition, the effect of ultraviolet and plasma mutagenesis was not merely simple superimposition of single ultraviolet mutation and single plasma mutation. Meanwhile, there appeared a capsule around some of the spores after the ultraviolet and plasma treatment, namely, the spore surface of the strain became fuzzy after ultraviolet or ultraviolet and plasma mutagenesis.

  18. Mutagenesis of Trichoderma Viride by Ultraviolet and Plasma

    Science.gov (United States)

    Yao, Risheng; Li, Manman; Deng, Shengsong; Hu, Huajia; Wang, Huai; Li, Fenghe

    2012-04-01

    Considering the importance of a microbial strain capable of increased cellulase production, a mutant strain UP4 of Trichoderma viride was developed by ultraviolet (UV) and plasma mutation. The mutant produced a 21.0 IU/mL FPase which was 98.1% higher than that of the parent strain Trichoderma viride ZY-1. In addition, the effect of ultraviolet and plasma mutagenesis was not merely simple superimposition of single ultraviolet mutation and single plasma mutation. Meanwhile, there appeared a capsule around some of the spores after the ultraviolet and plasma treatment, namely, the spore surface of the strain became fuzzy after ultraviolet or ultraviolet and plasma mutagenesis.

  19. The ultraviolet variations of iota Cas

    Science.gov (United States)

    Molnar, M. R.; Mallama, A. D.; Soskey, D. G.; Holm, A. V.

    1976-01-01

    The Ap variable star iota Cas was observed with the photometers on OAO-2 covering the spectral range 1430-4250 A. The ultraviolet light curves show a double wave with primary minimum and maximum at phase ? 0.00 and 0.35, respectively. Secondary minimum light is at phase ? 0.65 with secondary maximum at phase ? 0.85. The light curves longward of 3150 A vary in opposition to those shortward of this 'null region'. Ground-based coude spectra show that the Fe II and Cr II line strengths have a double-wave variation such that maximum strength occurs at minimum ultraviolet light. We suggest that the strong ultraviolet opacities due to photoionization and line blanketing by these metals may cause the observed photometric variations. We have also constructed an oblique-rotator model which shows iron and chromium lying in a great circle band rather than in circular spots.

  20. JUDE: An Ultraviolet Imaging Telescope pipeline

    Science.gov (United States)

    Murthy, J.; Rahna, P. T.; Sutaria, F.; Safonova, M.; Gudennavar, S. B.; Bubbly, S. G.

    2017-07-01

    The Ultraviolet Imaging Telescope (UVIT) was launched as part of the multi-wavelength Indian AstroSat mission on 28 September, 2015 into a low Earth orbit. A 6-month performance verification (PV) phase ended in March 2016, and the instrument is now in the general observing phase. UVIT operates in three channels: visible, near-ultraviolet (NUV) and far-ultraviolet (FUV), each with a choice of broad and narrow band filters, and has NUV and FUV gratings for low-resolution spectroscopy. We have written a software package (JUDE) to convert the Level 1 data from UVIT into scientifically useful photon lists and images. The routines are written in the GNU Data Language (GDL) and are compatible with the IDL software package. We use these programs in our own scientific work, and will continue to update the programs as we gain better understanding of the UVIT instrument and its performance. We have released JUDE under an Apache License.

  1. The ultraviolet telescope on the Astron satellite

    International Nuclear Information System (INIS)

    Boyarchuk, A.A.

    1987-01-01

    On 23 March 1983 in the USSR, the Astron astrophysical satellite, with the largest ultraviolet telescope (the UVT) in the world (main mirror diameter 80 cm) and a set of X-ray instruments on board was placed in a high-apogee orbit. The design of the ultraviolet telescope and the results of some of the observations carried out with it are described here. The X-ray instruments are discussed in a separate article. The ultraviolet telescope on the Astron astrophysical satellite is a result of the joint efforts of scientists and engineers at the Crimean Astrophysical Observatory (Academy of Sciences of the USSR), the Byurakan Astrophysical Observatory (Academy of Sciences of the Armenian USSR), and several industrial enterprises in our country. The Laboratoire d'Astronomie Spatiale (CNRS, Marseille, France) played a large role in building the spectrometer for the UVT

  2. Modelling and Display of the Ultraviolet Sky

    Science.gov (United States)

    Daniels, J.; Henry, R.; Murthy, J.; Allen, M.; McGlynn, T. A.; Scollick, K.

    1994-12-01

    A computer program is currently under development to model in 3D - one dimension of which is wavelength - all the known and major speculated sources of ultraviolet (900 A - 3100 A ) radiation over the celestial sphere. The software is being written in Fortran 77 and IDL and currently operates under IRIX (the operating system of the Silicon Graphics Iris Machine); all output models are in FITS format. Models along with display software will become available to the astronomical community. The Ultraviolet Sky Model currently includes the Zodiacal Light, Point Sources of Emission, and the Diffuse Galactic Light. The Ultraviolet Sky Model is currently displayed using SkyView: a package under development at NASA/ GSFC, which allows users to retrieve and display publically available all-sky astronomical survey data (covering many wavebands) over the Internet. We present a demonstration of the SkyView display of the Ultraviolet Model. The modelling is a five year development project: the work illustrated here represents product output at the end of year one. Future work includes enhancements to the current models and incorporation of the following models: Galactic Molecular Hydrogen Fluorescence; Galactic Highly Ionized Atomic Line Emission; Integrated Extragalactic Light; and speculated sources in the intergalactic medium such as Ionized Plasma and radiation from Non-Baryonic Particle Decay. We also present a poster which summarizes the components of the Ultraviolet Sky Model and outlines a further package that will be used to display the Ultraviolet Model. This work is supported by United States Air Force Contract F19628-93-K-0004. Dr J. Daniels is supported with a post-doctoral Fellowship from the Leverhulme Foundation, London, United Kingdom. We are also grateful for the encouragement of Dr Stephen Price (Phillips Laboratory, Hanscomb Air Force Base, MA)

  3. Molecular geometry in the ultraviolet absorption spectra

    International Nuclear Information System (INIS)

    Albuquerque, S.F. de; Monteiro, L.S.; Adamis, L.M.B.; Baltar, M.C.P.; Silva, R.M. da

    1977-01-01

    The ultraviolet absorption spectra may be sensibly affected by steric effects. These effects can cause a lot of difficulties and unexpected changes in spectrum. The most general source of such difficulties is steric inhibition of resonance. In addition to this, ultraviolet epectra may be markedly changed by steric factors which change the positions of dipoles in the molecule with respect to each other and by the interaction of nonconjugated chromophores suitably located in space. We have studied in detail each of these effects presenting a lot of usual and importants examples in Organic Chemistry. Others relevants subjects were not considerated in this present work [pt

  4. Disinfection of drinking water by ultraviolet light

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    It is no longer mandatory that a given residue of chlorine is present in drinking water and this has led to interest in the use of ultraviolet radiation for disinfection of water in large public waterworks. After a brief discussion of the effect of ultraviolet radiation related to wavelength, the most usual type of irradiation equipment is briefly described. Practioal considerations regarding the installation, such as attenuation of the radiation due to water quality and deposits are presented. The requirements as to dose and residence time are also discussed and finally it is pointed out that hydraulic imperfections can reduce the effectiveness drastically. (JIW)Ψ

  5. Nanoscale freestanding gratings for ultraviolet blocking filters

    Energy Technology Data Exchange (ETDEWEB)

    van Beek, J.T.; Fleming, R.C.; Hindle, P.S.; Prentiss, J.D.; Schattenburg, M.L. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Ritzau, S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1998-11-01

    Ultraviolet (UV) blocking filters are needed for atomic flux imaging in environments where high levels of ultraviolet radiation are present. Freestanding gratings are a promising candidate for UV filtering. They have a high aspect ratio ({approximately}13), narrow ({approximately}40 nm) slots, and effectively block UV radiation. The grating fabrication process makes use of several etching, electroplating, and lithographic steps and includes an optional step to plug pinholes induced by particles during processing. Gratings were successfully manufactured and tested. Measured UV transmissions of {approximately}10{sup {minus}5} and particle transmissions of {approximately}10{percent} are in agreement with theoretical predictions. {copyright} {ital 1998 American Vacuum Society.}

  6. Quartz glass behavior at ultraviolet spectrum region

    International Nuclear Information System (INIS)

    Braga, A.F.B.; Barbosa, L.C.; Evora, C.A.P.D.

    1990-01-01

    Melted quartz ingots were produced from raw materials of different sources. Behavior studies of these three different quartz glass were made at the eletromagnetic spectrum ultraviolet region. The atomic absorption spectroscopy was used as an analysis technique of the alkaline, transition and aluminum metal traces. It was found that the alkaline, transition and aluminum metals impurities present a great influence on the melted quartz spectral behavior at the ultraviolet region. It was stated that measurments at this spectrum region constitute an important characterization technique to natural quartz as well as melted quartz. (author) [pt

  7. Plasmonic enhancement of ultraviolet fluorescence

    Science.gov (United States)

    Jiao, Xiaojin

    Plasmonics relates to the interaction between electromagnetic radiation and conduction electrons at metallic interfaces or in metallic nanostructures. Surface plasmons are collective electron oscillations at a metal surface, which can be manipulated by shape, texture and material composition. Plasmonic applications cover a broad spectrum from visible to near infrared, including biosensing, nanolithography, spectroscopy, optoelectronics, photovoltaics and so on. However, there remains a gap in this activity in the ultraviolet (UV, research. Motivating factors in the study of UV Plasmonics are the direct access to biomolecular resonances and native fluorescence, resonant Raman scattering interactions, and the potential for exerting control over photochemical reactions. This dissertation aims to fill in the gap of Plasmonics in the UV with efforts of design, fabrication and characterization of aluminium (Al) and magnesium (Mg) nanostructures for the application of label-free bimolecular detection via native UV fluorescence. The first contribution of this dissertation addresses the design of Al nanostructures in the context of UV fluorescence enhancement. A design method that combines analytical analysis with numerical simulation has been developed. Performance of three canonical plasmonic structures---the dipole antenna, bullseye nanoaperture and nanoaperture array---has been compared. The optimal geometrical parameters have been determined. A novel design of a compound bullseye structure has been proposed and numerically analyzed for the purpose of compensating for the large Stokes shift typical of UV fluorescence. Second, UV lifetime modification of diffusing molecules by Al nanoapertures has been experimentally demonstrated for the first time. Lifetime reductions of ~3.5x have been observed for the high quantum yield (QY) laser dye p-terphenyl in a 60 nm diameter aperture with 50 nm undercut. Furthermore, quantum-yield-dependence of lifetime reduction has been

  8. ESA innovation rescues Ultraviolet Observatory

    Science.gov (United States)

    1995-10-01

    Astrophysicist Freeman J. Dyson from the Institute for Advanced Studies in Princeton characterizes IUE as "A little half-meter mirror sitting in the sky, unnoticed by the public, pouring out results". By use of the IUE satellite, astronomers obtain access to the ultraviolet radiation of celestial bodies in unique ways not available by any other means, neither from the ground nor by any other spacecraft currently in orbit. IUE serves a wide community of astronomers all over Europe, the United States and many other parts of the world. It allows the acquisition of critical data for fundamental studies of comets and their evaporation when they approach the Sun, of the mechanisms driving the stellar winds which make many stars lose a significant fraction of their mass (before they die slowly as White Dwarfs or in sudden Supernova explosions), as well as in the search to understand the ways in which black holes possibly power the violent nuclei of Active galaxies. One year ago the project was threatened with termination and serious concern was expressed by astronomers about the potential loss of IUE's capabilities, as a result of NASA not continuing to operate the spacecraft. Under the leadership of ESA, the three Agencies involved in the operations of IUE (ESA, NASA and the United Kingdom's Particle Physics and Astronomy Research Council, PPARC), reviewed the operations agreements of the Project. A minor investment allowing the implementation of modern management and engineering techniques as well as a complete revision of the communication infrastructure of the project and continuous improvements in efficiency in the ESA management, also taking advantage of today's technologies, both in computing and communications, have made it possible to continue IUE operations within the financial means available, with ESA taking up most of NASA's share in the operations. According to Dr. Willem Wamsteker, ESA's Dutch IUE Project Scientist, "it was a extremely interesting

  9. Far-ultraviolet spectral changes of titanium dioxide with gold nanoparticles by ultraviolet and visible light

    Science.gov (United States)

    Tanabe, Ichiro; Kurawaki, Yuji

    2018-05-01

    Attenuated total reflectance spectra including the far-ultraviolet (FUV, ≤ 200 nm) region of titanium dioxide (TiO2) with and without gold (Au) nanoparticles were measured. A newly developed external light-irradiation system enabled to observe spectral changes of TiO2 with Au nanoparticles upon light irradiations. Absorption in the FUV region decreased and increased by the irradiation with ultraviolet and visible light, respectively. These spectral changes may reflect photo-induced electron transfer from TiO2 to Au nanoparticles under ultraviolet light and from Au nanoparticles to TiO2 under visible light, respectively.

  10. Solar ultraviolet radiation in a changing climate

    Science.gov (United States)

    The projected large increases in damaging ultraviolet radiation as a result of global emissions of ozone-depleting substances have been forestalled by the success of the Montreal Protocol. New challenges are now arising in relation to climate change. We highlight the complex inte...

  11. Habitat impact on ultraviolet reflectance in moths

    Czech Academy of Sciences Publication Activity Database

    Zapletalová, Lenka; Zapletal, Michal; Konvička, Martin

    2016-01-01

    Roč. 45, č. 5 (2016), s. 1300-1305 ISSN 0046-225X R&D Projects: GA ČR(CZ) GA14-33733S Institutional support: RVO:60077344 Keywords : Lepidoptera * ultraviolet reflectance * mimicry Subject RIV: EH - Ecology, Behaviour Impact factor: 1.601, year: 2016

  12. Characterization of ethanol concentrations at ultraviolet wavelength ...

    African Journals Online (AJOL)

    This paper presents the measurement of optical absorption spectrum for different concentrations of ethanol at ultraviolet wavelength. Ethanol absorption spectrum was measured using portable spectroscopy setup from Avantes. It consists of Balanced Deuterium Halogen light source and spectrometer. The light source can ...

  13. Ultraviolet spectra of Mg in liquid helium

    International Nuclear Information System (INIS)

    Moriwaki, Y.; Morita, N.

    1999-01-01

    Emission and absorption spectra of Mg atoms implanted in liquid helium have been observed in the ultraviolet region. We have presented a model of exciplex formation of Mg-He 10 and found that this model is more suitable for understanding the dynamics in the 3s3p 1 P→3s 21 S transition than the bubble model. (orig.)

  14. Combined ultraviolet studies of astronomical sources

    Science.gov (United States)

    Baliunas, S. L.; Dupree, A. K.; Elvis, M.; Huchra, J. P.; Kenyon, S.; Raymond, J. C.

    1986-01-01

    Topics addressed include: Cygnus Loop; P Cygni profiles in dwarf novae; YY Gem; nova shells; HZ Herculis; activity cycles in cluster giants; Alpha Ori; metal deficient giant stars; ultraviolet spectra of symbiotic stars detected by the Very Large Array; time variability in symbiotic stars; blue galaxies; and quasistellar objects with X-ray spectra.

  15. The impact of ultraviolet radiation on timber

    International Nuclear Information System (INIS)

    Dawson, B.

    1993-01-01

    Photochemical degradation of timber, the outcome of exposure of timber to ultraviolet radiation, is a light induced chemical and physical decay. Timber is a collection of dead wood cells. Impacts of radiation on the growing tree are therefore outside the scope of this paper, which is primarily concerned with timber as a material. (author). 5 refs. 2 figs

  16. 21 CFR 878.4635 - Ultraviolet lamp for tanning.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultraviolet lamp for tanning. 878.4635 Section 878... tanning. (a) Identification. An ultraviolet lamp for tanning is a device that is a lamp (including a fixture) intended to provide ultraviolet radiation to tan the skin. See § 1040.20 of this chapter. (b...

  17. 21 CFR 880.6710 - Medical ultraviolet water purifier.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical ultraviolet water purifier. 880.6710... Miscellaneous Devices § 880.6710 Medical ultraviolet water purifier. (a) Identification. A medical ultraviolet water purifier is a device intended for medical purposes that is used to destroy bacteria in water by...

  18. Classical ultraviolet photoelectron spectroscopy of polymers

    International Nuclear Information System (INIS)

    Salaneck, W.R.

    2009-01-01

    Although X-ray photoelectron spectroscopy of polymers was well established by Clark and coworkers in the 1970s, ultraviolet photoelectron spectroscopy of polymer films, was developed later. Previous to the 1970s, the first attempts to use ultraviolet light on polymer films took the form of appearance potential (valence band edge) measurements. Only some years later could the full valence band region of thin polymer films, including insulating polymers, semiconducting polymers and electrically conducting polymers. The development of what might be termed 'classical ultraviolet photoelectron spectroscopy' of polymer films may be loosely based upon a variety of issues, including adapting thin polymer film technology to ultra high vacuum studies, the widespread use of helium resonance lamps for studies of solid surfaces, the combined advent of practical and sufficient theoretical-computational methods. The advent of, and the use of, easily available synchrotron radiation for multi-photon spectroscopies, nominally in the area of the near UV, is not included in the term 'classical'. At the same time, electrically conducting polymers were discovered, leading to applications of the corresponding semiconducting polymers, which added technologically driven emphasis to this development of ultraviolet photoelectron spectroscopy for polymer materials. This paper traces a limited number of highlights in the evolution of ultraviolet photoelectron spectroscopy of polymers, from the 1970s through to 2008. Also, since this issue is dedicated to Prof. Kazuhiko Seki, who has been a friend and competitor for over two decades, the author relies on some of Prof. Seki's earlier research, unpublished, on who-did-what-first. Prof. Seki's own contributions to the field, however, are discussed in other articles in this issue.

  19. Effect of ultraviolet exposure on mitochondrial respiratory system

    Energy Technology Data Exchange (ETDEWEB)

    Noda, K [Kurume Univ., Fukuoka (Japan). School of Medicine

    1975-09-01

    To find the photodynamic effect of ultraviolet light on the mitochondrial respiratory chain, mitochondria were obtained from rat livers, and the suspension was exposed to an extensive ultraviolet light. The oxygen consumption was measured polarographically with a Clark oxygen electrode. The effect of ultraviolet exposure on the five states of respiratory control (Chance and Williams), the P/O ratio, and the respiratory control index in mitochondria was discussed. The ultraviolet light with a dose of 9.6 x 10/sup 6/ erg/cm/sup 2/ caused the oxidative phosphorylation in mitochondria to uncouple. The 2nd phosphorylation site of the respiratory chain was susceptible to ultraviolet exposure. The stimulation of latent ATPase activity in mitochondria following exposure was observed by increasing exposure of ultraviolet light. However, DNP-stimulated ATPase was found to be stable in activity. The uncoupling of the respiratory chain by ultraviolet exposure was not detected if the mitochondrial suspension was preincubated with bovine serum albumin before exposure. The changes in light absorption of the mitochondrial suspension were followed at 520 nm after exposure. A close correlation was found between the ultraviolet exposure and swelling in mitochondria. But, the reversing contraction was observed by adding ATP to the swelled mitochondria. The peroxide compound was formed in mitochondria irradiated with ultraviolet light. The amount of compounds formed was dependent on the radiant energy of ultraviolet light. The possible mechanisms involved in the photodynamic effect of ultraviolet light to the mitochondrial respiration system were discussed.

  20. Nonlethal screening of bat-wing skin with the use of ultraviolet fluorescence to detect lesions indicative of white-nose syndrome.

    Science.gov (United States)

    Turner, Gregory G; Meteyer, Carol Uphoff; Barton, Hazel; Gumbs, John F; Reeder, DeeAnn M; Overton, Barrie; Bandouchova, Hana; Bartonička, Tomáš; Martínková, Natália; Pikula, Jiri; Zukal, Jan; Blehert, David S

    2014-07-01

    Definitive diagnosis of the bat disease white-nose syndrome (WNS) requires histologic analysis to identify the cutaneous erosions caused by the fungal pathogen Pseudogymnoascus [formerly Geomyces] destructans (Pd). Gross visual inspection does not distinguish bats with or without WNS, and no nonlethal, on-site, preliminary screening methods are available for WNS in bats. We demonstrate that long-wave ultraviolet (UV) light (wavelength 366-385 nm) elicits a distinct orange-yellow fluorescence in bat-wing membranes (skin) that corresponds directly with the fungal cupping erosions in histologic sections of skin that are the current gold standard for diagnosis of WNS. Between March 2009 and April 2012, wing membranes from 168 North American bat carcasses submitted to the US Geological Survey National Wildlife Health Center were examined with the use of both UV light and histology. Comparison of these techniques showed that 98.8% of the bats with foci of orange-yellow wing fluorescence (n=80) were WNS-positive based on histologic diagnosis; bat wings that did not fluoresce under UV light (n=88) were all histologically negative for WNS lesions. Punch biopsy samples as small as 3 mm taken from areas of wing with UV fluorescence were effective for identifying lesions diagnostic for WNS by histopathology. In a nonlethal biopsy-based study of 62 bats sampled (4-mm diameter) in hibernacula of the Czech Republic during 2012, 95.5% of fluorescent (n=22) and 100% of nonfluorescent (n=40) wing samples were confirmed by histopathology to be WNS positive and negative, respectively. This evidence supports use of long-wave UV light as a nonlethal and field-applicable method to screen bats for lesions indicative of WNS. Further, UV fluorescence can be used to guide targeted, nonlethal biopsy sampling for follow-up molecular testing, fungal culture analysis, and histologic confirmation of WNS.

  1. Nonlethal screening of bat-wing skin with the use of ultraviolet fluorescence to detect lesions indicative of white-nose syndrome

    Science.gov (United States)

    Turner, Gregory G.; Meteyer, Carol U.; Barton, Hazel; Gumbs, John F.; Reeder, DeeAnn M.; Overton, Barrie; Bandouchova, Hana; Bartonička, Tomáš; Martínková, Natália; Pikula, Jiri; Zukal, Jan; Blehert, David S.

    2014-01-01

    Definitive diagnosis of the bat disease white-nose syndrome (WNS) requires histologic analysis to identify the cutaneous erosions caused by the fungal pathogen Pseudogymnoascus [formerly Geomyces] destructans (Pd). Gross visual inspection does not distinguish bats with or without WNS, and no nonlethal, on-site, preliminary screening methods are available for WNS in bats. We demonstrate that long-wave ultraviolet (UV) light (wavelength 368–385 nm) elicits a distinct orange–yellow fluorescence in bat-wing membranes (skin) that corresponds directly with the fungal cupping erosions in histologic sections of skin that are the current gold standard for diagnosis of WNS. Between March 2009 and April 2012, wing membranes from 168 North American bat carcasses submitted to the U.S. Geological Survey National Wildlife Health Center were examined with the use of both UV light and histology. Comparison of these techniques showed that 98.8% of the bats with foci of orange–yellow wing fluorescence (n = 80) were WNS-positive based on histologic diagnosis; bat wings that did not fluoresce under UV light (n = 88) were all histologically negative for WNS lesions. Punch biopsy samples as small as 3 mm taken from areas of wing with UV fluorescence were effective for identifying lesions diagnostic for WNS by histopathology. In a nonlethal biopsy-based study of 62 bats sampled (4-mm diameter) in hibernacula of the Czech Republic during 2012, 95.5% of fluorescent (n = 22) and 100% of nonfluorescent (n = 40) wing samples were confirmed by histopathology to be WNS positive and negative, respectively. This evidence supports use of long-wave UV light as a nonlethal and field-applicable method to screen bats for lesions indicative of WNS. Further, UV fluorescence can be used to guide targeted, nonlethal biopsy sampling for follow-up molecular testing, fungal culture analysis, and histologic confirmation of WNS.

  2. ULTRAVIOLET HALOS AROUND SPIRAL GALAXIES. I. MORPHOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Hodges-Kluck, Edmund; Cafmeyer, Julian; Bregman, Joel N., E-mail: hodgeskl@umich.edu [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)

    2016-12-10

    We examine ultraviolet halos around a sample of highly inclined galaxies within 25 Mpc to measure their morphology and luminosity. Despite contamination from galactic light scattered into the wings of the point-spread function, we find that ultraviolet (UV) halos occur around each galaxy in our sample. Around most galaxies the halos form a thick, diffuse disk-like structure, but starburst galaxies with galactic superwinds have qualitatively different halos that are more extensive and have filamentary structure. The spatial coincidence of the UV halos above star-forming regions, the lack of consistent association with outflows or extraplanar ionized gas, and the strong correlation between the halo and galaxy UV luminosity suggest that the UV light is an extragalactic reflection nebula. UV halos may thus represent 10{sup 6}–10{sup 7} M {sub ⊙} of dust within 2–10 kpc of the disk, whose properties may change with height in starburst galaxies.

  3. Contact lens disinfection by ultraviolet light

    International Nuclear Information System (INIS)

    Dolman, P.J.; Dobrogowski, M.J.

    1989-01-01

    A 253.7-nm ultraviolet light with an intensity of 1,100 microW/cm2 was tested for its germicidal activity against contact lenses and storage solutions contaminated with various corneal pathogens. The exposure time necessary to reduce a concentration of organisms from 10(6)/ml to less than 10/ml was 30 seconds for Staphylococcus aureus, 60 seconds for Pseudomonas aeruginosa, and 84 seconds for Candida albicans. The time necessary to sterilize a suspension of 10(4)/ml Acanthamoeba polyphaga was less than three minutes with this technique. Four brands of soft contact lenses were exposed to ultraviolet light for over eight hours without changing their appearance, comfort, or refraction

  4. Effective polycrystalline sensor of ultraviolet radiation

    Directory of Open Access Journals (Sweden)

    S.Yu. Pavelets

    2017-10-01

    Full Text Available Deposition of special thin layers with high and low resistance in space charge region of surface barrier photoconverters based on the p-Cu1.8S/n-CdS structure leads to a sufficient increase in photosensitivity and decrease in dark tunneling-recombination current. Highly efficient and stable polycrystalline photoconverters of ultraviolet radiation based on polycrystalline CdS have been obtained. Electrical and photoelectric properties have been investigated, and the main operational parameters of ultraviolet sensors have been adduced. The reasons for high stability of the parameters inherent to the p-Cu1.8S/n-CdS sensors are as follows: the absence of impurity components additionally doped to the barrier structure and stability of the photocurrent photoemission component.

  5. Subdwarf ultraviolet excesses and metal abundances

    International Nuclear Information System (INIS)

    Carney, B.W.

    1979-01-01

    The relation between stellar ultraviolet excesses and abundances is reexamined with the aid of new data, and an investigation is made of the accuracy of previous abundance analyses. A high-resolution echellogram of the subdwarf HD 201891 is analyzed to illustrate some of the problems. Generally, the earliest and latest analytical techniques yield consistent results for dwarfs. New UBV data yield normalized ultraviolet excesses, delta (U-B)/sub 0.6/, which are compared to abundances to produce a graphical relation that may be used to estimate [Fe/H] to +- 0.2 dex, given UBV colors accurate to +- 0.01 mag. The relation suggests a possible discontinuity between the halo and old-disk stars

  6. Cosmetic and medical applications of ultraviolet radiation

    International Nuclear Information System (INIS)

    Diffey, B.L.

    1987-01-01

    The social desirability of a tanned skin is apparent and many people associate a bronzed body with good health and a sense of well-being. In Northern Europe and America the lack of long periods of sunshine has led to the establishment of the suntanning industry where artificial sources of ultraviolet radiation emitting almost entirely in the UV-A region supplement sunlight exposure

  7. Ultraviolet stability in euclidean scalar field theories

    Energy Technology Data Exchange (ETDEWEB)

    Benfatto, G; Cassandro, M; Gallavotti, G; Nicolo, F; Olivieri, E; Presutti, E; Scacciatelli, E [Rome Univ. (Italy). Istituto di Matematica; Rome Univ. (Italy). Istituto di Fisica)

    1980-01-01

    We develop a technique for reducing the problem of the ultraviolet divergences and their removal to a free field problem. This work is an example of a problem to which a rather general method can be applied. It can be thought as an attempt towards a rigorous version (in 2 or 3 space-time dimensions) of the analysis of the structure of the functional integrals, the underlying mechanism being essentially the same as in Glimms approach.

  8. Ultraviolet signals in birds are special.

    OpenAIRE

    Hausmann, Franziska; Arnold, Kathryn E; Marshall, N Justin; Owens, Ian P F

    2003-01-01

    Recent behavioural experiments have shown that birds use ultraviolet (UV)-reflective and fluorescent plumage as cues in mate choice. It remains controversial, however, whether such UV signals play a special role in sexual communication, or whether they are part of general plumage coloration. We use a comparative approach to test for a general association between sexual signalling and either UV-reflective or fluorescent plumage. Among the species surveyed, 72% have UV colours and there is a si...

  9. Impurity study of TMX using ultraviolet spectroscopy

    International Nuclear Information System (INIS)

    Allen, S.L.; Strand, O.T.; Moos, H.W.; Fortner, R.J.; Nash, T.J.; Dietrich, D.D.

    1981-01-01

    An extreme ultraviolet (EUV) study of the emissions from intrinsic and injected impurities in TMX is presented. Two survey spectrographs were used to determine that the major impurities present were oxygen, nitrogen, carbon, and titanium. Three absolutely-calibrated monochromators were used to measure the time histories and radial profiles of these impurity emissions in the central cell and each plug. Two of these instruments were capable of obtaining radial profiles as a function of time in a single shot

  10. Minimal length uncertainty relation and ultraviolet regularization

    Science.gov (United States)

    Kempf, Achim; Mangano, Gianpiero

    1997-06-01

    Studies in string theory and quantum gravity suggest the existence of a finite lower limit Δx0 to the possible resolution of distances, at the latest on the scale of the Planck length of 10-35 m. Within the framework of the Euclidean path integral we explicitly show ultraviolet regularization in field theory through this short distance structure. Both rotation and translation invariance can be preserved. An example is studied in detail.

  11. The Ultraviolet Index: a useful tool.

    Science.gov (United States)

    Kinney, J P; Long, C S

    2000-09-01

    The Ultraviolet Index was developed in the United States in 1994 following successful use of ultraviolet (UV) alerts in other countries. This daily National Weather Service prediction is a calculation which integrates five data elements to yield the amount of UV radiation impacting the surface (1m2) at solar noon in 58 of the largest US population centers. This simple numeric prediction is then categorized by the Environmental Protection Agency into five "exposure levels" with protective actions recommended for each level. This information is disseminated through the media. Daily reminders seem to affect awareness and behavior in Canada, but US surveys indicate the need for better understanding through educational graphics. Comparing the UV Index to a precipitation prediction has merit in that it links a familiar daily prediction with implied appropriate protective measures. Graphics link the ideas that "when it rains it pours and when it shines it radiates." Beginning in schools, camps, and dermatology meetings, using the rain/shine analogy, a wider exposure to the Ultraviolet Index is proposed.

  12. Inhibition of seagrass photosynthesis by ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Trocine, R.P.; Rice, J.D.; Wells, G.N.

    1981-01-01

    Effects of ultraviolet-B radiation on the photosynthesis of seagrasses (Halophila engelmanni Aschers, Halodule wrightii Aschers, and Syringodium filiforme (Kuetz) 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 ultraviolet-B were investigated. Halodule was found to possess the greatest photosynthetic tolerance for ultraviolet-B. Photosynthesis in Syringodium was slightly more sensitive to ultraviolet-B while Halophila showed relatively little photosynthetic tolerance. Evidence for a photorepair mechanism was found only in Halodule. Syringodium appeared to rely primarily on a thick epidermal cell layer to reduce photosynthetic damage. Halophila seemed to have no morphological or photorepair capabilities to deal with ultraviolet-B. This species appeared to rely on epiphytic and detrital shielding and the shade provided by other seagrasses to reduce ultraviolet-B irradiation to tolerable levels. The presence of epiphytes on leaf surfaces was found to reduce the extent of photosynthetic inhibition from ultraviolet-B exposure in all species. Halophila appears to obtain an increased photosynthetic tolerance to ultraviolet-B as an indirect benefit of chloroplast clumping to avoid photo-oxidation by intense levels of photosynthetically active radiation

  13. Disinfection Effect of Film Cassettes by Ultraviolet Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kweon, Dae Cheol; Park, Peom [Ajou Univ., Suwon (Korea, Republic of)

    2001-12-15

    A bacteria infection on film cassette contact surface was examined at the diagnostic radiology department. Studies have demonstrated a bactericidal effect of ultraviolet irradiation, and to assess the contamination level on film cassette contact surface as a predictor of patient prevent from nosocomial infection. The study showed that the laboratory result was identified non-pathologic and pathologic bacterial in the five different cassette size of the contact surface. Film cassettes were exposed to ultraviolet light for 1, 2 and 3 minutes. Ultraviolet light disinfection practices suitable for bacteria. The study concludes that presence of a bacterial infection will prevent a using antiseptic technique on film cassette contact surface. In conclusion, ultraviolet irradiate on film cassette over the surface more than 2 minutes. Ultraviolet dose of 1565 {mu}W {center_dot} s/cm{sup 2}Win in 30 second relative to ultraviolet dose in time.

  14. Disinfection Effect of Film Cassettes by Ultraviolet Irradiation

    International Nuclear Information System (INIS)

    Kweon, Dae Cheol; Park, Peom

    2001-01-01

    A bacteria infection on film cassette contact surface was examined at the diagnostic radiology department. Studies have demonstrated a bactericidal effect of ultraviolet irradiation, and to assess the contamination level on film cassette contact surface as a predictor of patient prevent from nosocomial infection. The study showed that the laboratory result was identified non-pathologic and pathologic bacterial in the five different cassette size of the contact surface. Film cassettes were exposed to ultraviolet light for 1, 2 and 3 minutes. Ultraviolet light disinfection practices suitable for bacteria. The study concludes that presence of a bacterial infection will prevent a using antiseptic technique on film cassette contact surface. In conclusion, ultraviolet irradiate on film cassette over the surface more than 2 minutes. Ultraviolet dose of 1565 μW · s/cm 2 Win in 30 second relative to ultraviolet dose in time

  15. Inhibition of seagrass photosynthesis by ultraviolet-B radiation.

    Science.gov (United States)

    Trocine, R P; Rice, J D; Wells, G N

    1981-07-01

    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 ultraviolet-B were investigated.Halodule was found to possess the greatest photosynthetic tolerance for ultraviolet-B. Photosynthesis in Syringodium was slightly more sensitive to ultraviolet-B while Halophila showed relatively little photosynthetic tolerance. Evidence for a photorepair mechanism was found only in Halodule. This mechanism effectively attenuated photosynthetic inhibition induced by ultraviolet-B dose rates and dosages in excess of natural conditions. Syringodium appeared to rely primarily on a thick epidermal cell layer to reduce photosynthetic damage. Halophila seemed to have no morphological or photorepair capabilities to deal with ultraviolet-B. This species appeared to rely on epiphytic and detrital shielding and the shade provided by other seagrasses to reduce ultraviolet-B irradiation to tolerable levels. The presence of epiphytes on leaf surfaces was found to reduce the extent of photosynthetic inhibition from ultraviolet-B exposure in all species.Observations obtained in this study seem to suggest the possibility of anthocyanin and/or other flavonoid synthesis as an adaptation to long term ultraviolet-B irradiation by these species. In addition, Halophila appears to obtain an increased photosynthetic tolerance to ultraviolet-B as an indirect benefit of chloroplast clumping to avoid photo-oxidation by intense levels of photosynthetically active radiation.

  16. Ultraviolet spectrophotometer for measuring columnar atmospheric ozone from aircraft

    Science.gov (United States)

    Hanser, F. A.; Sellers, B.; Briehl, D. C.

    1978-01-01

    An ultraviolet spectrophotometer (UVS) to measure downward solar fluxes from an aircraft or other high altitude platform is described. The UVS uses an ultraviolet diffuser to obtain large angular response with no aiming requirement, a twelve-position filter wheel with narrow (2-nm) and broad (20-nm) bandpass filters, and an ultraviolet photodiode. The columnar atmospheric ozone above the UVS (aircraft) is calculated from the ratios of the measured ultraviolet fluxes. Comparison with some Dobson station measurements gives agreement to 2%. Some UVS measured ozone profiles over the Pacific Ocean for November 1976 are shown to illustrate the instrument's performance.

  17. In-orbit Calibrations of the Ultraviolet Imaging Telescope

    Science.gov (United States)

    Tandon, S. N.; Subramaniam, Annapurni; Girish, V.; Postma, J.; Sankarasubramanian, K.; Sriram, S.; Stalin, C. S.; Mondal, C.; Sahu, S.; Joseph, P.; Hutchings, J.; Ghosh, S. K.; Barve, I. V.; George, K.; Kamath, P. U.; Kathiravan, S.; Kumar, A.; Lancelot, J. P.; Leahy, D.; Mahesh, P. K.; Mohan, R.; Nagabhushana, S.; Pati, A. K.; Kameswara Rao, N.; Sreedhar, Y. H.; Sreekumar, P.

    2017-09-01

    The Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in ASTROSAT, the first Indian Space Observatory. The UVIT instrument has two 375 mm telescopes: one for the far-ultraviolet (FUV) channel (1300-1800 Å), and the other for the near-ultraviolet (NUV) channel (2000-3000 Å) and the visible (VIS) channel (3200-5500 Å). UVIT is primarily designed for simultaneous imaging in the two ultraviolet channels with spatial resolution better than 1.″8, along with provisions for slit-less spectroscopy in the NUV and FUV channels. The results of in-orbit calibrations of UVIT are presented in this paper.

  18. In-orbit Calibrations of the Ultraviolet Imaging Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Tandon, S. N. [Inter-University Center for Astronomy and Astrophysics, Pune (India); Subramaniam, Annapurni; Sankarasubramanian, K.; Sriram, S.; Stalin, C. S.; Mondal, C.; Sahu, S.; Joseph, P.; Barve, I. V.; George, K.; Kamath, P. U.; Kathiravan, S.; Kumar, A.; Lancelot, J. P.; Mahesh, P. K. [Indian Institute of Astrophysics, Koramangala II Block, Bangalore-560034 (India); Girish, V. [ISRO Satellite Centre, HAL Airport Road, Bangalore 560017 (India); Postma, J.; Leahy, D. [University of Calgary, 2500 University Drive NW, Calgary, Alberta Canada (Canada); Hutchings, J. [National Research Council of Canada, Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Ghosh, S. K., E-mail: purni@iiap.res.in [National Centre for Radio Astrophysics, Pune (India); and others

    2017-09-01

    The Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in ASTROSAT, the first Indian Space Observatory. The UVIT instrument has two 375 mm telescopes: one for the far-ultraviolet (FUV) channel (1300–1800 Å), and the other for the near-ultraviolet (NUV) channel (2000–3000 Å) and the visible (VIS) channel (3200–5500 Å). UVIT is primarily designed for simultaneous imaging in the two ultraviolet channels with spatial resolution better than 1.″8, along with provisions for slit-less spectroscopy in the NUV and FUV channels. The results of in-orbit calibrations of UVIT are presented in this paper.

  19. Ultraviolet air disinfection for protection against influenza

    International Nuclear Information System (INIS)

    Riley, R.L.

    1977-01-01

    Three converging lines of evidence support the belief that it may be possible, under appropriate circumstances, to interrupt the airborne transmission of influenza by ultraviolet (UV) air disinfection. These lines of evidence are: (a) that influenza is airborne; (b) that UV irradiation of the upper air of a room can provide safe and effective disinfection of air in the lower part of the room; and (c) that epidemic spread of airborne viral infections in humans can be prevented if the population under consideration remains in the UV-protected environment

  20. Far ultraviolet spectrophotometry of BD +28 4211

    Science.gov (United States)

    Cook, Timothy A.; Cash, Webster; Green, James C.

    1991-01-01

    The results are reported of a November 1989 rocket flight which recorded a flux-calibrated spectrum of BD +28 4211 from 912 to 1150 A with 1A resolution. BD +28 4211, an SdO-type star, is commonly used as an ultraviolet calibration source in the IUE wavelength band. The present work extends the useful range of this standard shortward of Lyman-alpha. Since previous experiments show marked disparity, this study can be useful in determining a standard in the 912 to 1216 A band.

  1. Probing nanoscale ferroelectricity by ultraviolet Raman spectroscopy.

    Science.gov (United States)

    Tenne, D A; Bruchhausen, A; Lanzillotti-Kimura, N D; Fainstein, A; Katiyar, R S; Cantarero, A; Soukiassian, A; Vaithyanathan, V; Haeni, J H; Tian, W; Schlom, D G; Choi, K J; Kim, D M; Eom, C B; Sun, H P; Pan, X Q; Li, Y L; Chen, L Q; Jia, Q X; Nakhmanson, S M; Rabe, K M; Xi, X X

    2006-09-15

    We demonstrated that ultraviolet Raman spectroscopy is an effective technique to measure the transition temperature (Tc) in ferroelectric ultrathin films and superlattices. We showed that one-unit-cell-thick BaTiO3 layers in BaTiO3/SrTiO3 superlattices are not only ferroelectric (with Tc as high as 250 kelvin) but also polarize the quantum paraelectric SrTiO3 layers adjacent to them. Tc was tuned by approximately 500 kelvin by varying the thicknesses of the BaTiO3 and SrTiO3 layers, revealing the essential roles of electrical and mechanical boundary conditions for nanoscale ferroelectricity.

  2. Ultraviolet Flux Variation of Epsilon Aurigae

    Directory of Open Access Journals (Sweden)

    Young Woon Kang

    1990-06-01

    Full Text Available The eighteen ultraviolet light curves of Epsilon Aurigae have been plotted using the integrated fluxes reduced from the 233 IUE low dispersion spectra taken between 1978 and 1986. The times of contacts and depth of eclipse have been determined from the light curves at the wavelength from 2550 Å to 3050 Å. The UV light curves show two brightenings during the totality, the downward slope of the variation from the second to the third contacts, and asymmetry of the eclipse light curve. The two selected spectra note that the energy density distribution is not changed between the totality of the eclipse and out-of-eclipse.

  3. Dynamical structure of extreme ultraviolet macrospicules

    Science.gov (United States)

    Karovska, Margarita; Habbal, Shadia Rifai

    1994-01-01

    We describe the substructures forming the macrospicules and their temporal evolution, as revealed by the application of an image enhancement algorithm to extreme ultraviolet (EUV) observations of macrospicules. The enhanced images uncover, for the first time, the substructures forming the column-like structures within the macrospicules and the low-lying arches at their base. The spatial and temporal evolution of macrospicules clearly show continuous interaction between these substructures with occasional ejection of plasma following a ballistic trajectory. We comment on the importance of these results for planning near future space observations of macrospicules with better temporal and spatial resolution.

  4. Impact of Ultraviolet Light on Vitiligo.

    Science.gov (United States)

    Singh, Rasnik K

    2017-01-01

    Vitiligo is a disorder of the melanocytes that results in a dynamic spectrum of skin depigmentation. Its etiology is complex and multifactorial, with data supporting several different hypotheses. Given its prominent phenotype, vitiligo has a significant negative impact on quality of life. Coupled with the chronic and incurable nature of the disease, this presents a formidable treatment challenge. Several treatment modalities have been instituted over the years, with varying efficacy. This chapter focuses on the use of ultraviolet light in vitiligo as an established therapeutic option.

  5. FAINT NEAR-ULTRAVIOLET/FAR-ULTRAVIOLET STANDARDS FROM SWIFT/UVOT, GALEX, AND SDSS PHOTOMETRY

    International Nuclear Information System (INIS)

    Siegel, Michael H.; Hoversten, Erik A.; Roming, Peter W. A.; Brown, Peter

    2010-01-01

    At present, the precision of deep ultraviolet photometry is somewhat limited by the dearth of faint ultraviolet standard stars. In an effort to improve this situation, we present a uniform catalog of 11 new faint (u ∼ 17) ultraviolet standard stars. High-precision photometry of these stars has been taken from the Sloan Digital Sky Survey and Galaxy Evolution Explorer archives and combined with new data from the Swift Ultraviolet Optical Telescope to provide precise photometric measures extending from the near-infrared to the far-ultraviolet. These stars were chosen because they are known to be hot (20, 000 eff < 50, 000 K) DA white dwarfs with published Sloan spectra that should be photometrically stable. This careful selection allows us to compare the combined photometry and Sloan spectroscopy to models of pure hydrogen atmospheres to both constrain the underlying properties of the white dwarfs and test the ability of white dwarf models to predict the photometric measures. We find that the photometry provides good constraints on white dwarf temperatures, which demonstrates the ability of Swift/UVOT to investigate the properties of hot luminous stars. We further find that the models reproduce the photometric measures in all 11 passbands to within their systematic uncertainties. Within the limits of our photometry, we find the standard stars to be photometrically stable. This success indicates that the models can be used to calibrate additional filters to our standard system, permitting easier comparison of photometry from heterogeneous sources. The largest source of uncertainty in the model fitting is the uncertainty in the foreground reddening curve, a problem that is especially acute in the UV.

  6. Ultraviolet and Infrared Correlation Studies in Orion

    Directory of Open Access Journals (Sweden)

    Bose Lakshmi S.

    2015-09-01

    Full Text Available We have studied the variation of diffuse ultraviolet (UV radiation in the northern part of the Orion constellation using a set of eight areas of the GALEX All-Sky Imaging Survey in the far and near UV. Different components of diffuse UV radiation, like dust scattered emission and H2 fluorescence, were quantified and separated after removing the point sources and the foreground emission in each of the fields. Then the dependence of the individual UV components on the infrared 100 μm dust emission was studied. We did not find any positive correlation between the diffuse-UV and IR-100 micron intensities, probably due to the high optical depth of the region or the entire dust column not contributing to the diffuse UV radiation. However, in the far UV we noticed the presence of an excess emission in addition to the dust scattered radiation, which is clearly absent in the near UV. This excess emission, identified as the H2 fluorescence, is produced by the Trapezium stars in the surrounding molecular clouds. We also compare our results with those of previous studies in the region, based on Far Ultraviolet Spectroscopic Explorer (FUSE observations.

  7. ULTRAVIOLET EXTINCTION AT HIGH GALACTIC LATITUDES

    Energy Technology Data Exchange (ETDEWEB)

    Peek, J. E. G.; Schiminovich, David, E-mail: jegpeek@gmail.com [Department of Astronomy, Columbia University, New York, NY (United States)

    2013-07-01

    In order to study the properties and effects of high Galactic latitude dust, we present an analysis of 373,303 galaxies selected from the Galaxy Evolution Explorer All-Sky Survey and Wide-field Infrared Explorer All-Sky Data Release. By examining the variation in aggregate ultraviolet colors and number density of these galaxies, we measure the extinction curve at high latitude. We additionally consider a population of spectroscopically selected galaxies from the Sloan Digital Sky Survey to measure extinction in the optical. We find that dust at high latitude is neither quantitatively nor qualitatively consistent with standard reddening laws. Extinction in the FUV and NUV is {approx}10% and {approx}35% higher than expected, with significant variation across the sky. We find that no single R{sub V} parameter fits both the optical and ultraviolet extinction at high latitude, and that while both show detectable variation across the sky, these variations are not related. We propose that the overall trends we detect likely stem from an increase in very small silicate grains in the interstellar medium.

  8. ULTRAVIOLET EXTINCTION AT HIGH GALACTIC LATITUDES

    International Nuclear Information System (INIS)

    Peek, J. E. G.; Schiminovich, David

    2013-01-01

    In order to study the properties and effects of high Galactic latitude dust, we present an analysis of 373,303 galaxies selected from the Galaxy Evolution Explorer All-Sky Survey and Wide-field Infrared Explorer All-Sky Data Release. By examining the variation in aggregate ultraviolet colors and number density of these galaxies, we measure the extinction curve at high latitude. We additionally consider a population of spectroscopically selected galaxies from the Sloan Digital Sky Survey to measure extinction in the optical. We find that dust at high latitude is neither quantitatively nor qualitatively consistent with standard reddening laws. Extinction in the FUV and NUV is ∼10% and ∼35% higher than expected, with significant variation across the sky. We find that no single R V parameter fits both the optical and ultraviolet extinction at high latitude, and that while both show detectable variation across the sky, these variations are not related. We propose that the overall trends we detect likely stem from an increase in very small silicate grains in the interstellar medium.

  9. Inhibition of DNA replication by ultraviolet light

    International Nuclear Information System (INIS)

    Edenberg, H.J.

    1976-01-01

    DNA replication in ultraviolet-irradiated HeLa cells was studied by two different techniques: measurements of the kinetics of semiconservative DNA synthesis, and DNA fiber autoradiography. In examining the kinetics of semiconservative DNA synthesis, density label was used to avoid measuring the incorporation due to repair replication. The extent of inhibition varied with time. After doses of less than 10 J/m 2 the rate was initially depressed but later showed some recovery. After higher doses, a constant, low rate of synthesis was seen for at least the initial 6 h. An analysis of these data indicated that the inhibition of DNA synthesis could be explained by replication forks halting at pyrimidine dimers. DNA fiber autoradiography was used to further characterize replication after ultraviolet irradiation. The average length of labeled segments in irradiated cells increased in the time immediately after irradiation, and then leveled off. This is the predicted pattern if DNA synthesis in each replicon continued at its previous rate until a lesion is reached, and then halted. The frequency of lesions that block synthesis is approximately the same as the frequency of pyrimidine dimers

  10. Photomorphogenic responses to ultraviolet-B light.

    Science.gov (United States)

    Jenkins, Gareth I

    2017-11-01

    Exposure to ultraviolet B (UV-B) light regulates numerous aspects of plant metabolism, morphology and physiology through the differential expression of hundreds of genes. Photomorphogenic responses to UV-B are mediated by the photoreceptor UV RESISTANCE LOCUS8 (UVR8). Considerable progress has been made in understanding UVR8 action: the structural basis of photoreceptor function, how interaction with CONSTITUTIVELY PHOTOMORPHOGENIC 1 initiates signaling and how REPRESSOR OF UV-B PHOTOMORPHOGENESIS proteins negatively regulate UVR8 action. In addition, recent research shows that UVR8 mediates several responses through interaction with other signaling pathways, in particular auxin signaling. Nevertheless, many aspects of UVR8 action remain poorly understood. Most research to date has been undertaken with Arabidopsis, and it is important to explore the functions and regulation of UVR8 in diverse plant species. Furthermore, it is essential to understand how UVR8, and UV-B signaling in general, regulates processes under natural growth conditions. Ultraviolet B regulates the expression of many genes through UVR8-independent pathways, but the activity and importance of these pathways in plants growing in sunlight are poorly understood. © 2017 John Wiley & Sons Ltd.

  11. STELLAR ACTIVITY IN THE BROADBAND ULTRAVIOLET

    International Nuclear Information System (INIS)

    Findeisen, K.; Hillenbrand, L.; Soderblom, D.

    2011-01-01

    The completion of the GALEX All-Sky Survey in the ultraviolet allows activity measurements to be acquired for many more stars than is possible with the limited sensitivity of ROSAT or the limited sky coverage of Chandra, XMM, or spectroscopic surveys for line emission in the optical or ultraviolet. We have explored the use of GALEX photometry as an activity indicator, using stars within 50 pc as a calibration sample representing the field and in selected nearby associations representing the youngest stages of stellar evolution. We present preliminary relations between UV flux and the optical activity indicator R' HK and between UV flux and age. We demonstrate that far-UV (FUV, 1350-1780 A) excess flux is roughly proportional to R' HK . We also detect a correlation between near-UV (NUV, 1780-2830 A) flux and activity or age, but the effect is much more subtle, particularly for stars older than ∼0.5-1 Gyr. Both the FUV and NUV relations show large scatter, ∼0.2 mag when predicting UV flux, ∼0.18 dex when predicting R' HK , and ∼0.4 dex when predicting age. This scatter appears to be evenly split between observational errors in current state-of-the-art data and long-term activity variability in the sample stars.

  12. Pollen and spores as biological recorders of past ultraviolet irradiance

    NARCIS (Netherlands)

    Jardine, P.E.; Fraser, W.T.; Lomax, B.H.; Sephton, M.A.; Shanahan, T.M.; Miller, C.S.; Gosling, W.D.

    2016-01-01

    Solar ultraviolet (UV) irradiance is a key driver of climatic and biotic change. Ultraviolet irradiance modulates stratospheric warming and ozone production, and influences the biosphere from ecosystem-level processes through to the largest scale patterns of diversification and extinction. Yet our

  13. Ultraviolet radiation, human health, and the urban forest

    Science.gov (United States)

    Gordon M. Heisler; Richard H. Grant

    2000-01-01

    Excess exposure to ultraviolet (UV) radiation from the sun, particularly the ultraviolet B (UVB) portion, has been linked with adverse effects on human health ranging from skin cancers to eye diseases such as cataracts. Trees may prevent even greater disease rates in humans by reducing UV exposure. Tree shade greatly reduces UV irradiance when both the sun and sky are...

  14. An assessment of ultraviolet radiation components of light emitted ...

    African Journals Online (AJOL)

    An assessment of ultraviolet radiation components of light emitted from electric arc and their possible exposure risks. ... The study of Ultraviolet Radiation has of recent become interesting because of the health hazards it poses to human. Apart from its intensity reaching the earth from the sun, other man-made sources have ...

  15. 21 CFR 872.6070 - Ultraviolet activator for polymerization.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultraviolet activator for polymerization. 872.6070 Section 872.6070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... ultraviolet radiation intended to polymerize (set) resinous dental pit and fissure sealants or restorative...

  16. 21 CFR 880.6500 - Medical ultraviolet air purifier.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical ultraviolet air purifier. 880.6500 Section 880.6500 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... to ultraviolet radiation. (b) Classification. Class II (performance standards). ...

  17. 21 CFR 878.4630 - Ultraviolet lamp for dermatologic disorders.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultraviolet lamp for dermatologic disorders. 878.4630 Section 878.4630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... disorders is a device (including a fixture) intended to provide ultraviolet radiation of the body to...

  18. Ultraviolet microscopy aids in cytological and biomedical research

    Science.gov (United States)

    Schlenk, F.; Svihla, B.

    1967-01-01

    Ultraviolet microscopy is used by cytologists and biochemists to study the morphological and physiological changes in the living cell under varied culture conditions. The yeast cell is used because of its content of ultraviolet absorbing materials and its lack of motility.

  19. Ultraviolet solar radiation and the prevention of erythema

    International Nuclear Information System (INIS)

    Tena, F.; Martinez-Lozano, J.A.; Utrillas, M.P.

    1998-01-01

    An ultraviolet index appropriate for its use in Spain is studied on the basis of those already available in other countries. The suitability of this index to characterise ultraviolet solar radiation and, particularly, the potential risks to human health are discussed. Finally, the main factors affecting this index are identified and their influence is studied. (Author) 43 refs

  20. Does ultraviolet radiation affect the xanthophyll cycle in marine phytoplankton?

    NARCIS (Netherlands)

    van de Poll, W.H.; Buma, A.G.J.

    2009-01-01

    This Perspective summarizes the state of knowledge of the impact of ultraviolet radiation on the photoprotective xanthophyll cycle in marine phytoplankton. Excess photosynthetically active radiation (PAR; 400-700 nm) and ultraviolet radiation (UVR; 280-400 nm) affect various cellular processes and

  1. Ultraviolet radiation, cancer of the skin and immunology

    International Nuclear Information System (INIS)

    Suurmond, D.

    1984-01-01

    The effects of near and far ultraviolet radiation on the development of skin neoplasms are reviewed. Especially the role of ultraviolet radiation in immunosuppression is discussed as a possible working mechanism of the tumor promoting the effect of this radiation, beside effects on DNA-repair. (Auth.)

  2. Resveratrol anti-ultraviolet-induced guinea pig skin injury

    International Nuclear Information System (INIS)

    Li Wenxing; Zhao Ying

    2014-01-01

    Objective: To Estimate on the protection effect of Stilbene on skin damage induced by ultraviolet radiation. Methods: After the normal skin in guinea pig under the intervene of Resveratrol was irradiated with over- dose of ultraviolet rays (UVB and UVA), the samples in every group were matched and compared. Results: The skin tissue in the Resveratrol intervene group irradiated by ultraviolet rays didn't change obviously as compared with that in the self-control group. But, the damage skin tissue in the control group irradiated by ultraviolet did change significantly as compared with that in the Stilbene intervene group. Conclusion: Resveratrol is a good material to protect the skin from damage effect by ultraviolet radiation. (authors)

  3. Color signaling in conspicuous red sticklebacks: do ultraviolet signals surpass others?

    Directory of Open Access Journals (Sweden)

    Bakker Theo CM

    2008-07-01

    Full Text Available Abstract Background The use of ultraviolet (UV signals for communication tasks is widespread in vertebrates. For instance, there is a UV component to mate choice in several species. Nevertheless, it remains unclear how the signal value of the UV wave band compares to that of other regions of the animal's visible spectrum. We investigated the relative importance of UV signals compared with signals of longer wavelengths in the threespine stickleback (Gasterosteus aculeatus, a species using UV wavelengths in female and male mate choice as well as in shoaling behavior. In a choice experiment, female sticklebacks were simultaneously presented with four male visual appearances manipulated by optical filters. Each male lacked one wavelength range of the stickleback's visible spectrum corresponding to the spectral sensitivities of the four cone types. The resulting male appearances thus had no UV (UV-, no short-wave (SW-, no medium-wave (MW- or no long-wave (LW- body reflectance. Results Males without UV wavelengths and long wavelengths ("red" were least preferred. In contrast, the removal of medium and most notably short wavelengths left male attractiveness to females rather unaffected. Using color metrics, the effects of the four optical filters on stickleback perception of three male body regions were illustrated as quantal catches calculated for the four single cones. Conclusion The removal of UV light (UV- considerably reduced visual attractiveness of courting males to female three-spined sticklebacks particularly in comparison to the removal of short-wave light (SW-. We thus report first experimental evidence that the UV wave band clearly outranks at least one other part of an animal's visible spectrum (SW- in the context of communication. In addition, females were also less attracted to males presented without long wavelengths (LW- which supports the traditionally considered strong influence of the red color component on stickleback mate choice

  4. High intensity vacuum ultraviolet and extreme ultraviolet production by noncollinear mixing in laser vaporized media

    Energy Technology Data Exchange (ETDEWEB)

    Todt, Michael A.; Albert, Daniel R.; Davis, H. Floyd, E-mail: hfd1@cornell.edu [Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301 (United States)

    2016-06-15

    A method is described for generating intense pulsed vacuum ultraviolet (VUV) and extreme ultraviolet (XUV) laser radiation by resonance enhanced four-wave mixing of commercial pulsed nanosecond lasers in laser vaporized mercury under windowless conditions. By employing noncollinear mixing of the input beams, the need of dispersive elements such as gratings for separating the VUV/XUV from the residual UV and visible beams is eliminated. A number of schemes are described, facilitating access to the 9.9–14.6 eV range. A simple and convenient scheme for generating wavelengths of 125 nm, 112 nm, and 104 nm (10 eV, 11 eV, and 12 eV) using two dye lasers without the need for dye changes is described.

  5. Ultraviolet-visible spectroscopy of graphene oxides

    Directory of Open Access Journals (Sweden)

    Qi Lai

    2012-09-01

    Full Text Available Dispersions of few-layer (1-3 layers, multi-layer (4-10 layers and thick-layer (>10 layers graphene oxide (GO were prepared by a modified Hummers method with different mass ratios of KMnO4 to graphite. Ultraviolet-visible (UV-vis spectroscopic data show that few-layer GO dispersions can be distinguished from multi- and thick-layer dispersions by a more intense peak at 230 nm. Atomic force microscopy (AFM images of few-layer GO contain a single peak, those of multi-layer GO exhibit a shoulder and those of thick-layer GO do not contain a peak or shoulder. These findings allow qualitative analysis of GO dispersions. X-ray photoelectron spectra (XPS show that the change of UV-vis absorption intensity of GO is caused by a conjugative effect related to chromophore aggregation that influences the π-π* plasmon peak.

  6. Preoperative ultraviolet B inflammation in skin

    DEFF Research Database (Denmark)

    Lunn, T H; Dawes, J M; Denk, F

    2018-01-01

    BACKGROUND: Neuroimmune interactions play a vital role in many of the most common pain conditions, such as arthritis. There have been many attempts to derive clinically predictive information from an individual's inflammatory response in order to gauge subsequent pain perception. OBJECTIVES: Here......, we wanted to test whether this effort could be enhanced and complemented by the use of a model system which takes into account the function of not just circulating, but also tissue-resident immune cells: ultraviolet B (UVB) irradiation of the skin. METHODS: We conducted psychophysical...... in the skin might predict the degree of a patient's neuro-immune response and the extent of their postoperative pain after total knee arthroplasty....

  7. Recovery of phage lambda from ultraviolet damage

    International Nuclear Information System (INIS)

    Devoret, R.; Blanco, M.; George, J.; Radman, M.

    1975-01-01

    Recovery of phage lambda from ultraviolet damage can occur, in the dark, through three types of repair processes as defined by microbiological tests: host-cell reactivation, prophage reactivation, and uv reactivation. This paper reviews the properties of the three repair processes, analyzes their dependence on the functioning of bacterial and phage genes, and discusses their relationship. Progress in the understanding of the molecular mechanisms underlying the three repair processes has been relatively slow, particularly for uv reactivation. It has been shown that host-cell reactivation is due to pyrimidine dimer excision and that prophage reactivation is due to genetic recombination (prereplicative). We provide evidence showing that neither of these mechanisms accounts for uv reactivation of phage lambda. Furthermore, uv reactivation differs from the other repair processes in that it is inducible and error-prone. Whether uv-damaged bacterial DNA is subject to a similar repair process is still an open question

  8. Al nanogrid electrode for ultraviolet detectors.

    Science.gov (United States)

    Ding, G; Deng, J; Zhou, L; Gan, Q; Hwang, J C M; Dierolf, V; Bartoli, F J; Mazuir, C; Schoenfeld, W V

    2011-09-15

    Optical properties of Al nanogrids of different pitches and gaps were investigated both theoretically and experimentally. Three-dimensional finite-difference time-domain simulation predicted that surface plasmons at the air/Al interface would enhance ultraviolet transmission through the subwavelength gaps of the nanogrid, making it an effective electrode on GaN-based photodetectors to compensate for the lack of transparent electrode and high p-type doping. The predicted transmission enhancement was verified by confocal scanning optical microscopy performed at 365 nm. The quality of the nanogrids fabricated by electron-beam lithography was verified by near-field scanning optical microscopy and scanning electron microscopy. Based on the results, the pitch and gap of the nanogrids can be optimized for the best trade-off between electrical conductivity and optical transmission at different wavelengths. Based on different cutoff wavelengths, the nanogrids can also double as a filter to render photodetectors solar-blind.

  9. Some resistance mechanisms to ultraviolet radiation

    International Nuclear Information System (INIS)

    Alcantara D, D.

    2002-12-01

    The cyclical exposure of bacterial cells to the ultraviolet light (UV) it has as consequence an increment in the resistance to the lethal effects of this type of radiation, increment that happens as a result of a selection process of favorable genetic mutations induced by the same UV light. With object to study the reproducibility of the genetic changes and the associate mechanisms to the resistance to UV in the bacteria Escherichia coli, was irradiated cyclically with UV light five different derived cultures of a single clone, being obtained five stumps with different resistance grades. The genetic mapping Hfr revealed that so much the mutation events like of selection that took place during the adaptation to the UV irradiation, happened of random manner, that is to say, each one of the resistant stumps it is the result of the unspecified selection of mutations arisen at random in different genes related with the repair and duplication of the DNA. (Author)

  10. Phototherapy cabinet for ultraviolet radiation therapy

    International Nuclear Information System (INIS)

    Horwitz, S.N.; Frost, P.

    1981-01-01

    A newly designed cabinet can be used for the treatment of psoriasis with fluorescent ultraviolet (UV) lamps. the new design provides more uniform distribution of UV radiation in both the horizontal and vertical axes, and several safety features have been added. The distribution and uniformity of UV output in this and in a previously described cabinet are compared. The UV output at the vertical center of the older UV light cabinet was six times greater than that at either the top or bottom, while the design of the present cabinet provides uniform UV radiation except for a slight increase at head height and at the level of the lower legs compared with the middle third of the cabinet. The variation in output of the older cabinet may, in part, explain the commonly encountered difficulty in the phototherapy of psoriasis of the scalp and lower extremities

  11. Ultraviolet-laser ablation of skin

    Energy Technology Data Exchange (ETDEWEB)

    Lane, R.J.; Linsker, R.; Wynne, J.J.; Torres, A.; Geronemus, R.G.

    1985-05-01

    The authors report on the use of pulsed ultraviolet-laser irradiation at 193 nm from an argon-fluoride laser and at 248 nm from a krypton-fluoride laser to ablate skin. In vitro, both wavelengths performed comparably, removing tissue precisely and cleanly, and leaving minimal thermal damage to the surrounding tissue. In vivo, the 193-nm laser radiation failed to remove tissue after bleeding began. The 248-nm radiation, however, continued to remove tissue despite bleeding and left a clean incision with only minimal thermal damage. The krypton-fluoride excimer laser beam at 248 nm, which should be deliverable through a quartz optical fiber, has great potential as a surgical instrument.

  12. Solar maximum ultraviolet spectrometer and polarimeter

    Science.gov (United States)

    Tandberg-Hanssen, E.; Woodgate, B. E.; Brandt, J. C.; Chapman, R. D.; Hyder, C. L.; Michalitsianos, A. G.; Shine, R. A.; Athay, R. G.; Beckers, J. M.; Bruner, E. C.

    1979-01-01

    The objectives of the UVSP experiment are to study solar ultraviolet radiations, particularly from flares and active regions, and to measure constituents in the terrestrial atmosphere by the extinction of sunlight at satellite dawn and dusk. The instrument is designed to observe the Sun at a variety of spectral and spatial resolutions in the range from 1150 to 3600 A. A Gregorian telescope with effective focal length of 1.8 m is used to feed a 1 m Ebert-Fastie spectrometer. A polarimeter containing rotatable magnesium fluoride waveplates is included behind the spectrometer entrance slit and will allow all four Stokes parameters to be determined. Velocities on the Sun can also be measured. The instrument is controlled by a computer which can interact with the data stream to modify the observing program. The observing modes, including rasters, spectral scans, velocity measurements, and polarimetry, are also described along with plans for mission operations, data handling, and analysis of the observations.

  13. Ultraviolet reflectance by the cere of raptors

    Science.gov (United States)

    Mougeot, François; Arroyo, Beatriz E

    2006-01-01

    Ultraviolet (UV) signals have been shown to play key roles in social and sexual signalling in birds. Using a spectrophotometer, we analysed the colour of the cere (skin above the beak) of a diurnal raptor, the Montagu's harrier (Circus pygargus), and show that it reflects in the UV part of the spectrum. The cere is a well-known sexual signal in raptors, with carotenoid based pigmentation being indicative of quality. We thus hypothesized that UV reflectance also signals quality. Accordingly, we found that in our sample of wild males, the location of the UV peak was related to the orangeness of cere and correlated with male body mass and condition (mass corrected for size). Also, males with brighter UV were mated to females that laid earlier, as expected if UV reflectance relates to a male's quality and attractiveness. Future studies should investigate the relationships between UV reflectance and carotenoid pigmentation of cere, and test how UV reflectance influences mate choice. PMID:17148356

  14. Free-electron lasers in ultraviolet photobiology

    International Nuclear Information System (INIS)

    Coohill, T.P.; Sutherland, J.C.

    1989-01-01

    The potential uses for a free-electron laser (FEL), tunable in wavelength from 10 to 400 nm, for photobiological experiments is discussed. Inherent problems of cell and molecular absorption, especially in certain regions of the ultraviolet (UV), are addressed. Absorption values for living cells and viruses at selected wavelengths in the UV are tabulated, and a calculation of the flux needed to inactivate mammalian cells is included. A comparison is made of the UV output of a proposed rf-linac FEL with those of a monochromator, a tunable dye laser, and a synchrotron. The advantages of a UV FEL are apparent, especially in the wavelength regions where the cross section for absorption by biological molecules is low, i.e., 300 to 400 nm and 10 to 200 nm. It is apparent that a UV FEL would be an ideal source for a variety of biological studies that use both intact organisms and isolated cells and viruses

  15. Protection from solar ultraviolet radiation by clothing

    Energy Technology Data Exchange (ETDEWEB)

    Pailthorpe, M. [New South Wales Univ., Kensington, NSW (Australia)

    1996-12-31

    The recently published Australia/New Zealand Standard AS/NZS 4399: l996 `Sun Protective Clothing - Evaluation and Classification` specifies an in vitro spectrophotometric method for the measurement of the ultraviolet (WR) transmission of textiles. Ultraviolet Protection Factors (UPF) are then calculated by convolving the UVR transmission data with standard CIE erythemal response data and ARL solar irradiance data. At the present time the scope of the standard is limited to loose fitting dry clothing. Virtually every textile parameter has an influence on the UPF of the finished garment and hence on the protection afforded to skin from the harmful effects of solar UVR radiation. Textile parameters such as fibre type, the method of spinning the yarn, fabric structure, cover factor, colorant, UVR absorbers and finishing methods determine the UPF of the fabric and hence must be controlled from batch to batch. Since garments generally shrink when washed, multiple wearing and washing cycles usually cause an increase in fabric UPF. Adventitious soiling of fabrics and the absorption of certain components of domestic laundry formulations, e g fluorescent whitening agents, increase fabric UPF ratings. Garments with a high degree of elasticity, e g nylon/lycra sportswear, that are stretched on to fit, will obviously have lower UPFs when stretched than when relaxed. In general fabrics worn in a wet state provide lower protection than when worn dry. On Australia`s most extreme summer day it has been estimated that there are 30 MEDs (minimal erythemal doses) in a dawn to dusk exposure. Thus outdoor workers should be provided with UPF 30 clothing, or better. Results from recent experiments using SK-II hairless mice dressed in UPF 50 `sunsuits` have shown that the mice developed no sun induced skin cancers on the skin areas protected by the UPF 50 fabric whereas multiple tumours developed on the unprotected skin.

  16. Ultraviolet A1 phototherapy: One center's experience

    Directory of Open Access Journals (Sweden)

    Sasi Kiran Attili

    2017-01-01

    Full Text Available Background: Ultraviolet A1(UVA1 phototherapy is increasingly being used in the treatment of morphea, atopic dermatitis, lupus and some other recalcitrant dermatoses. We present a retrospective review of our experience with this modality. Aim: To evaluate the treatment response rates for various dermatoses and adverse effects of UVA1 phototherapy. Methods: We reviewed phototherapy notes along with electronic and/or paper case records for all patients treated with UVA1 phototherapy from October 1996 to December 2008. Results: A total of 269 patients (outcomes available for 247 had 361 treatment courses (treatment data available for 317 courses over this period. We found phototherapy to be beneficial in 28 (53% of 53 patients with atopic dermatitis and 19 (51% of 37 patients with morphea. A beneficial outcome was recorded in all six (100% cases of urticaria and six (85.7% of seven patients treated for a polymorphic light eruption. Benefit was also recorded in systemic lupus erythematosus (8 (44.4% of 18, lichen sclerosus (6 (42.9% of 14, mastocytosis (2 (33.3% of 6, necrobiosis lipoidica (4 (30.8% of 13, granuloma annulare (2 (25% of 8, scleroderma (2 (22.2% of 9 and keloids (1 (7.7% of 13. Overall, treatment was well tolerated with no patients having to stop treatment due to adverse effects. Limitations: This is a retrospective study with no control group. Subjective/recall bias is quite possible as a number of patients were followed up over the phone. Conclusions: Our data suggest that ultraviolet A1 can be considered for the treatment of selected dermatoses. However, long-term malignancy risk is as yet unknown.

  17. Protection from solar ultraviolet radiation by clothing

    International Nuclear Information System (INIS)

    Pailthorpe, M.

    1996-01-01

    The recently published Australia/New Zealand Standard AS/NZS 4399: l996 'Sun Protective Clothing - Evaluation and Classification' specifies an in vitro spectrophotometric method for the measurement of the ultraviolet (WR) transmission of textiles. Ultraviolet Protection Factors (UPF) are then calculated by convolving the UVR transmission data with standard CIE erythemal response data and ARL solar irradiance data. At the present time the scope of the standard is limited to loose fitting dry clothing. Virtually every textile parameter has an influence on the UPF of the finished garment and hence on the protection afforded to skin from the harmful effects of solar UVR radiation. Textile parameters such as fibre type, the method of spinning the yarn, fabric structure, cover factor, colorant, UVR absorbers and finishing methods determine the UPF of the fabric and hence must be controlled from batch to batch. Since garments generally shrink when washed, multiple wearing and washing cycles usually cause an increase in fabric UPF. Adventitious soiling of fabrics and the absorption of certain components of domestic laundry formulations, e g fluorescent whitening agents, increase fabric UPF ratings. Garments with a high degree of elasticity, e g nylon/lycra sportswear, that are stretched on to fit, will obviously have lower UPFs when stretched than when relaxed. In general fabrics worn in a wet state provide lower protection than when worn dry. On Australia's most extreme summer day it has been estimated that there are 30 MEDs (minimal erythemal doses) in a dawn to dusk exposure. Thus outdoor workers should be provided with UPF 30 clothing, or better. Results from recent experiments using SK-II hairless mice dressed in UPF 50 'sunsuits' have shown that the mice developed no sun induced skin cancers on the skin areas protected by the UPF 50 fabric whereas multiple tumours developed on the unprotected skin

  18. Ultraviolet-Mediated Activation of Photo toxins from Peganum Harmala L. Seedlings to Control both Human-and Phyto-Pathogenic Microorganisms and Tumor Cells

    International Nuclear Information System (INIS)

    Kord, M.; Khafagi, I.; Dewedar, A.

    2003-01-01

    The medicinal plant Peganum harmala L. (zygophyllaceae) contains a number of Beta-carboline alkaloids, which are photosensitizers to bacteria, yeasts and eukaryotic cells in the presence of sunlight and artificial sources of long-wave UV radiation (365 nm). Ultraviolet irradiation of ten-day old aseptically germinated Peganum harmala inoculated on bacterial and yeast bioassay plates elicits strong phototoxic antimicrobials. Callus as well as crude methanol extracts of in vitro cultures were also investigated for the accumulation of photosensitizers. High performance liquid chromatographic analyses of irradiated and control tissues followed by fluorescent detection at 302 nm revealed the formation of serotonin (5-hydroxytryptamine) in irradiated tissues only. Eluted compounds detected at 330 nm revealed more than ten-fold accumulation of harmine, isoharmine and harmol in irradiated tissues. Moreover, several simple beta-carboline alkaloids were produced through irradiation with UV such as harmalanine and harmalacidine. UV-induced phototoxicity was proven against phyto pathogenic bacteria and human-pathogenic bacteria and yeasts. Photo-induced cytotoxicity was observed from two different toxicity bioassays, which are Artemia saline and potato discs tumor assay. The selective UV-dependent biological activities may imply a pharmacological potential of Peganum harmala in the control of infectious diseases and tumor tissues

  19. Exposure to ultraviolet radiation: recommendations for cosmetic use

    International Nuclear Information System (INIS)

    Dias, C.; Carvalho, F.R.S.

    2000-01-01

    The beginning of the so-called tanning industry made possible the acquisition of a tanned skin independently of the available solar radiation. The tan is produced by ultraviolet radiation and, as well as in solar exposure, there are additional risks on the use of the so-called sun-beds. The damaging effects of ultraviolet exposure are well documented and reasonably quantified. The objective of this paper is to inform the potential effects of ultraviolet radiation exposure in sun-beds and to provide recommendations in order to reduce the associated risks. These recommendations are adapted for cosmetics use only (author)

  20. Biological applications of ultraviolet free-electron lasers

    International Nuclear Information System (INIS)

    Sutherland, J.C.

    1997-10-01

    This review examines the possibilities for biological research using the three ultraviolet free-electron lasers that are nearing operational status in the US. The projected operating characteristics of major interest in biological research of the free-electron lasers at Brookhaven National Laboratory, the Thomas Jefferson National Accelerator Facility, and Duke University are presented. Experimental applications in the areas of far- and vacuum ultraviolet photophysics and photochemistry, structural biology, environmental photobiology, and medical research are discussed and the prospects for advances in these areas, based upon the characteristics of the new ultraviolet free-electron lasers, are evaluated

  1. Extreme ultraviolet spectral irradiance measurements since 1946

    Science.gov (United States)

    Schmidtke, G.

    2015-03-01

    In the physics of the upper atmosphere the solar extreme ultraviolet (EUV) radiation plays a dominant role controlling most of the thermospheric/ionospheric (T/I) processes. Since this part of the solar spectrum is absorbed in the thermosphere, platforms to measure the EUV fluxes became only available with the development of rockets reaching altitude levels exceeding 80 km. With the availability of V2 rockets used in space research, recording of EUV spectra started in 1946 using photographic films. The development of pointing devices to accurately orient the spectrographs toward the sun initiated intense activities in solar-terrestrial research. The application of photoelectric recording technology enabled the scientists placing EUV spectrometers aboard satellites observing qualitatively strong variability of the solar EUV irradiance on short-, medium-, and long-term scales. However, as more measurements were performed more radiometric EUV data diverged due to the inherent degradation of the EUV instruments with time. Also, continuous recording of the EUV energy input to the T/I system was not achieved. It is only at the end of the last century that there was progress made in solving the serious problem of degradation enabling to monitore solar EUV fluxes with sufficient radiometric accuracy. The data sets available allow composing the data available to the first set of EUV data covering a period of 11 years for the first time. Based on the sophisticated instrumentation verified in space, future EUV measurements of the solar spectral irradiance (SSI) are promising accuracy levels of about 5% and less. With added low-cost equipment, real-time measurements will allow providing data needed in ionospheric modeling, e.g., for correcting propagation delays of navigation signals from space to earth. Adding EUV airglow and auroral emission monitoring by airglow cameras, the impact of space weather on the terrestrial T/I system can be studied with a spectral terrestrial

  2. Solar ultraviolet irradiance measurements, instrumentation, intercomparisons and interpretations

    International Nuclear Information System (INIS)

    Thorseth, Trond Morten

    2000-01-01

    The thesis reports studies of stabile instruments that are capable of detecting small alterations in ultraviolet irradiation over a long period. A central theme in the work has been to improve the measuring systems for continuous research based monitoring of natural variations in the ultraviolet irradiation from the sun. Methods for controlling the stability and continually secure the quality of the collected data. The causes of measuring errors are mapped and methods for the correction of collected data are developed. The methods and measuring systems for collecting the data have been adapted to the Norwegian climate and geography. The work has lead to an increased understanding of the natural variation in the ultraviolet radiation from the sun and what factors in the atmosphere that influences the process. The collected data and the developed methods for the quality control have increased the understanding of the ultraviolet irradiation climate in Europe

  3. Solar ultraviolet irradiance measurements, instrumentation, intercomparisons and interpretations

    Energy Technology Data Exchange (ETDEWEB)

    Thorseth, Trond Morten

    2000-07-01

    The thesis reports studies of stabile instruments that are capable of detecting small alterations in ultraviolet irradiation over a long period. A central theme in the work has been to improve the measuring systems for continuous research based monitoring of natural variations in the ultraviolet irradiation from the sun. Methods for controlling the stability and continually secure the quality of the collected data. The causes of measuring errors are mapped and methods for the correction of collected data are developed. The methods and measuring systems for collecting the data have been adapted to the Norwegian climate and geography. The work has lead to an increased understanding of the natural variation in the ultraviolet radiation from the sun and what factors in the atmosphere that influences the process. The collected data and the developed methods for the quality control have increased the understanding of the ultraviolet irradiation climate in Europe.

  4. Photoprotective Effect of Tea and its Extracts against Ultraviolet ...

    African Journals Online (AJOL)

    Ultraviolet (UV) exposure induces photodamage of skin. It is a matter of ... to the skin as well as the photoprotective effects of tea and its extracts have been highlighted. ..... storage of skin cream supplemented with green tea catechins or EGCG ...

  5. Protective effect of (-)-epigallocatechin gallate on ultraviolet b ...

    African Journals Online (AJOL)

    Purpose: To investigate the protective effect of green tea (-)-epigallocatechin gallate (EGCg) on ultraviolet B (UV-B)-induced skin damages in hairless mice in order to develop a natural sunscreen ... hydrophilic cream has also showed high.

  6. High Data Rate Optical Wireless Communications Based on Ultraviolet Band

    KAUST Repository

    Sun, Xiaobin

    2017-01-01

    Optical wireless communication systems based on ultraviolet (UV)-band has a lot inherent advantages, such as low background solar radiation, low device dark noise. Besides, it also has small restrictive requirements for PAT (pointing, acquisition

  7. Ultraviolet and environmental stresses involved in the induction and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-29

    Dec 29, 2008 ... regulating plant development and genes expression. Ultraviolet takes up 7% of ... Fax: 82-33-241-6480. fruits, vegetables, flowers, and other plant tissues or ... Structural classification of general anthocyanidin species (Tahara ...

  8. Photosynthetic carbon reduction by seagrasses exposed to ultraviolet A radiation

    Science.gov (United States)

    1979-01-01

    The seagrasses Halophila engelmannii, Halodule wrightii, and Syringodium filiforme were examined for their intrinsic sensitivity to ultraviolet-A-UV-A and ultraviolet-B-UV-B radiation. The effect of UV-A on photosynthetically active radiation (PAR) was also determined. Ultraviolet-A and ultraviolet-B were studied with emphasis on the greater respective environmental consequence in terms of seagrass distribution and abundance. Results indicate that an intrinsic sensitivity to UV-A alone is apparent only in Halophila, while net photosynthesis in Halodule and Syringodium seems unaffected by the level of UV-A provided. The sensitivity of Halophila to UV-A in the absense of (PAR) indicates that the photosynthetic reaction does not need to be in operation for damage to occur. Other significant results are reported.

  9. Polymer filters for ultraviolet-excited integrated fluorescence sensing

    International Nuclear Information System (INIS)

    Dandin, Marc; Abshire, Pamela; Smela, Elisabeth

    2012-01-01

    Optical filters for blocking ultraviolet (UV) light were fabricated by doping various polymer hosts with a UV absorbing chromophore. The polymers were polydimethylsiloxane (PDMS), a silicone elastomer frequently used in microfluidics, SU-8, a photopatternable epoxy, and Humiseal 1B66, an acrylic coating used for moisture protection of integrated circuits. The chromophore was 2-(2′-hydroxy-5′-methylphenyl) benzotriazole (BTA), which has a high extinction coefficient between 300 nm and 400 nm. We demonstrate filters 5 µm thick that exhibit high ultraviolet rejection (nearly −40 dB at 342 nm) yet pass visible light (near 0 dB above 400 nm), making them ideal for ultraviolet-excited fluorescence sensing within microsystems. The absorbance of the BTA depended on the host polymer. These filters are promising for integrated fluorescence spectroscopy in bioanalytical platforms because they can be patterned by dry etching, molding or exposure to ultraviolet light. (paper)

  10. Ultraviolet light in the use of water disinfection

    International Nuclear Information System (INIS)

    Dabbagh, R.

    1999-01-01

    Ultraviolet light is an effective method in the use of water disinfection for swimming pools, potable water and industry required water. For many reasons Ultraviolet light and Ultraviolet compounded with chlorine (Ultraviolet/chlorine) has been brought to attention ed in resent years. In this research, a swimming pool water disinfection was carried out by means of a system with the use of a reactor which was made of stainless steel (SS-304) and with many another standards required. Operation of system was carried out at first in the pilot plant and then installation in essential water treatment integrated. Inactivation of pollution index, E. Coli or Total coliform and Pseudomonas aeroginosa studies with 6000,16000 and 30000 μW.s/cm 2 Ultraviolet dose and then in presence of 0.3,0.6,0.9 and 1.2 mg/1 free chlorine (Ultraviolet/chlorine). In swimming pools minimum free chlorine residual usually is 1.5 mg/1. Optimum Ultraviolet dose was 16000 μW.s/cm 2 attention to 50 percent Ultraviolet absorption ca sued to TSS,TDS and turbidity. In the Ultraviolet/chlorine system suitable rate was 16000μW.s/cm 2 Ultraviolet dose/0.6 mg/1 chlorine in the 2.4 * 10 5 CFU/100 ml for Total coliform and 3600 CFU/100 ml for Pseudomonas aeroginosa. Most probable number (MPN) estimated multiple tube fermentation technique. In this way the flow rate for system indicated about 240 cm 3 /s or 0.9 m 3 /h. The samples polluted for secondary pollution with 54000 CFU/100 ml for E. Coli and 1800 CFU/100ml Pseudomonas aeroginosa. The number of microbes decreased to zero duration after 45 minutes contact time in presence of free chlorine residual in samples. In practical conditions which that disinfectant system was installed in essential water treatment circuit under 1.4 atm hydraulic pressure no growth was seen for pollution index in disinfected water with Ultraviolet in microbial density about 840 CFU/100 ml for Total coliform and 12 CFU/100 ml for pseudomonas aeroginosa. Attention to lower

  11. Ultraviolet damage resistance of laser coatings

    International Nuclear Information System (INIS)

    Newnam, B.E.; Gill, D.H.

    1978-01-01

    The damage resistance of several thin-film materials used in ultraviolet laser optics was measured at 266 and 355 nm. The coatings included single, quarterwave (QW) layers of NaF, LaF 3 , MgF 2 , ThO 2 , Al 2 O 3 , HfO 2 , ZrO 2 , Y 2 O 3 and SiO 2 , plus multilayer reflectors composed of some of these materials. The substrates were uv-grade fused silica. Single-shot thresholds were obtained with 22 ns and 27 ns (FWHM) pulses at 266 and 355 nm, respectively. One of the samples had previously been tested using 20-ps pulses, providing a pulsewidth comparison. At 266 nm the coating with the highest damage threshold was a QW layer of NaF at 10.8 J/cm 2 (450 MW/cm 2 ), whereas for a maximum reflector of Al 2 O 3 /NaF the value was 3.6 J/cm 2 (154 MW/cm 2 ), and the threshold of the maximum reflector was 12.2 J/cm 2 (470 MW/cm 2 ). The results were analyzed to determine correlations with standing-wave electric fields and linear and two-photon absorption. Scaling relationships for wavelength, refractive index and atomic density, and pulsewidth were found

  12. Ultraviolet and Visible Emission Mechanisms in Astrophysics

    Science.gov (United States)

    Stancil, Phillip C.; Schultz, David R.

    2003-01-01

    The project involved the study of ultraviolet (UV) and visible emission mechanisms in astrophysical and atmospheric environments. In many situations, the emission is a direct consequence of a charge transferring collision of an ion with a neutral with capture of an electron to an excited state of the product ion. The process is also important in establishing the ionization and thermal balance of an astrophysical plasma. As little of the necessary collision data are available, the main thrust of the project was the calculation of total and state-selective charge transfer cross sections and rate coefficients for a very large number of collision systems. The data was computed using modern explicit techniques including the molecular-orbital close-coupling (MOCC), classical trajectory Monte Carlo (CTMC), and continuum distorted wave (CDW) methods. Estimates were also made in some instances using the multichannel Landau-Zener (MCLZ) and classical over-the-barrier (COB) models. Much of the data which has been computed has been formatted for inclusion in a charge transfer database on the World Wide Web (cfadc.phy.ornl.gov/astro/ps/data/). A considerable amount of data has been generated during the lifetime of the grant. Some of it has not been analyzed, but it will be as soon as possible, the data placed on our website, and papers ultimately written.

  13. Hermite scatterers in an ultraviolet sky

    Science.gov (United States)

    Parker, Kevin J.

    2017-12-01

    The scattering from spherical inhomogeneities has been a major historical topic in acoustics, optics, and electromagnetics and the phenomenon shapes our perception of the world including the blue sky. The long wavelength limit of ;Rayleigh scattering; is characterized by intensity proportional to k4 (or λ-4) where k is the wavenumber and λ is the wavelength. With the advance of nanotechnology, it is possible to produce scatterers that are inhomogeneous with material properties that are functions of radius r, such as concentric shells. We demonstrate that with proper choice of material properties linked to the Hermite polynomials in r, scatterers can have long wavelength scattering behavior of higher powers: k8, k16, and higher. These ;Hermite scatterers; could be useful in providing unique signatures (or colors) to regions where they are present. If suspended in air under white light, the back-scattered spectrum would be shifted from blue towards violet and then ultraviolet as the higher order Hermite scatterers were illuminated.

  14. A private ultraviolet channel in visual communication.

    Science.gov (United States)

    Cummings, Molly E; Rosenthal, Gil G; Ryan, Michael J

    2003-01-01

    Although private communication is considered an important diversifying force in evolution, there is little direct behavioural evidence to support this notion. Here, we show that ultraviolet (UV) signalling in northern swordtails (Xiphophorus) affords a channel for communication that is not accessible to their major predator, Astyanax mexicanus, the Mexican tetra. Laboratory and field behavioural experiments with swordtails (X. nigrensis) and predators (A. mexicanus) demonstrate that male UV ornamentation significantly increases their attractiveness to females but not to this predator, which is less sensitive to UV. UV reflectance among swordtail species correlates positively with tetra densities across habitats, and visual contrast estimates suggest that UV signals are highly conspicuous to swordtails in their natural environment. Cross-species comparisons also support the hypothesis that natural selection drives the use of UV communication. We compared two species, one with high (X. nigrensis) and one with low (X. malinche) Mexican tetra densities. Xiphophorus nigrensis males reflect significantly more UV than X. malinche, exhibit significant UV sexual dimorphism, and UV is a salient component of the sexual communication system. In X. malinche, however, males reflect minimally in the UV, there is no UV sexual dimorphism, and UV does not play a part in its communication system. PMID:12803903

  15. Ultraviolet vision may be widespread in bats

    Science.gov (United States)

    Gorresen, P. Marcos; Cryan, Paul; Dalton, David C.; Wolf, Sandy; Bonaccorso, Frank

    2015-01-01

    Insectivorous bats are well known for their abilities to find and pursue flying insect prey at close range using echolocation, but they also rely heavily on vision. For example, at night bats use vision to orient across landscapes, avoid large obstacles, and locate roosts. Although lacking sharp visual acuity, the eyes of bats evolved to function at very low levels of illumination. Recent evidence based on genetics, immunohistochemistry, and laboratory behavioral trials indicated that many bats can see ultraviolet light (UV), at least at illumination levels similar to or brighter than those before twilight. Despite this growing evidence for potentially widespread UV vision in bats, the prevalence of UV vision among bats remains unknown and has not been studied outside of the laboratory. We used a Y-maze to test whether wild-caught bats could see reflected UV light and whether such UV vision functions at the dim lighting conditions typically experienced by night-flying bats. Seven insectivorous species of bats, representing five genera and three families, showed a statistically significant ‘escape-toward-the-light’ behavior when placed in the Y-maze. Our results provide compelling evidence of widespread dim-light UV vision in bats.

  16. Ultraviolet induced lysosome activity in corneal epithelium

    Energy Technology Data Exchange (ETDEWEB)

    Cullen, A.P.

    1980-01-01

    A 5.000 W Xe-Hg high pressure lamp and a double monochromator were used to produce a 3.3 nm half-bandpass ultraviolet radiation at 295 nm. Pigmented rabbit eyes were irradiated with radiant exposures from 140 Jm/sup -2/ to 10.000 Jm/sup -2/ and evaluated by slit-lamp biomicroscopy, light and electron microscopy. Corneal threshold (Hsub(c) was 200 Jm/sup -2/ and lens threshold (Hsub(L)) was 7.500 Jm/sup -2/. The most repeatable and reliable corneal response to these levels of UV was the development of corneal epithelial granules. Histological changes included a loss of superficial epithelial cells and selective UV induced autolysis of the wing cells. It is suggested that the biomicroscopically observed granules are the clinical manifestation of the secondary lysosomes revealed by light and electron microscopy. It is proposed that UV breaks down the primary lysosome membranes to release hydrolytic enzymes which in turn form the secondary lysosomes during autolysis. Extreme levels of radiant exposure at 295 nm result in indiscriminate destruction of all layers of the corneal epithelium, but the posterior cornea was spared.

  17. Ultraviolet induced lysosome activity in corneal epithelium

    International Nuclear Information System (INIS)

    Cullen, A.P.

    1980-01-01

    A 5.000 W Xe-Hg high pressure lamp and a double monochromator were used to produce a 3.3 nm half-bandpass ultraviolet radiation at 295 nm. Pigmented rabbit eyes were irradiated with radiant exposures from 140 Jm -2 to 10.000 Jm -2 and evaluated by slit-lamp biomicroscopy, light and electron microscopy. Corneal threshold (Hsub(c) was 200 Jm -2 and lens threshold (Hsub(L)) was 7.500 Jm -2 . The most repeatable and reliable corneal response to these levels of UV was the development of corneal epithelial granules. Histological changes included a loss of superficial epithelial cells and selective UV induced autolysis of the wing cells. It is suggested that the biomicroscopically observed granules are the clinical manifestation of the secondary lysosomes revealed by light and electron microscopy. It is proposed that UV breaks down the primary lysosome membranes to release hydrolytic enzymes which in turn form the secondary lysosomes during autolysis. Extreme levels of radiant exposure at 295 nm result in indiscriminate destruction of all layers of the corneal epithelium, but the posterior cornea was spared. (orig.) [de

  18. Pathways of ultraviolet mutability in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Lemontt, J.F.

    1977-01-01

    Non-allelic mutants of Saccharomyces cerevisiae with reduced capacity for ultraviolet light (UV)-induced forward mutation from CAN1 to can1 were assigned to seven distinct genetic loci, each with allele designations umr1-1, umr2-1, ..., umr7-1 to indicate UV mutation resistance. None conferred a great deal of UV sensitivity. When assayed on yeast extract-peptone-dextrose complex growth agar, umr1, umr3, and umr7 were the most UV-sensitive. When assayed on synthetic agar lacking arginine, however, umr3 was the most UV-sensitive. All strains carrying each of the seven umr genes exhibited varying degrees of defective UV mutability, compact with wild types. Normal UV revertibility of three different alleles was observed in strains carrying either umr4, umr5, umr6, or umr7. Five a/α homozygous umr diploids failed to sporulate. One of these, umr7, blocked normal secretion of alpha hormone in α segregants and could not conjugate with a strains. The phenotypes of umr mutants are consistent with the existence of branched UV mutation pathways of different specificity

  19. Low-energy QCD and ultraviolet renormalons

    International Nuclear Information System (INIS)

    Peris, S.

    1997-01-01

    We discuss the contribution of ultraviolet (UV) renormalons in QCD to two-point functions of quark current operators. This explicitly includes effects due to the exchange of one renormalon chain as well as two chains. It is shown that, when the external Euclidean momentum of the two-point functions becomes smaller than the scale Λ L associated with the Landau singularity of the QCD one-loop running coupling constant, the positions of the UV renormalons in the Borel plane become true singularities in the integration range of the Borel transform. This introduces ambiguities in the evaluation of the corresponding two-point functions. The ambiguities associated with the leading UV renormalon singularity are of the same type as the contribution due to the inclusion of dimension d=6 local operators in a low-energy effective Lagrangian valid at scales smaller than Λ L . We then discuss the inclusion of an infinite number of renormalon chains and argue that the previous ambiguity hints at a plausible approximation scheme for low-energy QCD, resulting in an effective Lagrangian similar to the one of the extended Nambu-Jona-Lasinio (ENJL) model of QCD at large N c . (orig.)

  20. Vacuum ultraviolet photoionization of carbohydrates and nucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Joong-Won, E-mail: jshin@govst.edu [Division of Science, Governors State University, University Park, Illinois 60484-0975 (United States); Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872 (United States); Bernstein, Elliot R., E-mail: erb@lamar.colostate.edu [Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872 (United States)

    2014-01-28

    Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5{sup ′}-monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate, rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C–C and C–O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results.

  1. Vacuum ultraviolet photoionization of carbohydrates and nucleotides

    International Nuclear Information System (INIS)

    Shin, Joong-Won; Bernstein, Elliot R.

    2014-01-01

    Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5 ′ -monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate, rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C–C and C–O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results

  2. Biological Sensors for Solar Ultraviolet Radiation

    Directory of Open Access Journals (Sweden)

    André P. Schuch

    2011-04-01

    Full Text Available Solar ultraviolet (UV radiation is widely known as a genotoxic environmental agent that affects Earth ecosystems and the human population. As a primary consequence of the stratospheric ozone layer depletion observed over the last decades, the increasing UV incidence levels have heightened the concern regarding deleterious consequences affecting both the biosphere and humans, thereby leading to an increase in scientific efforts to understand the role of sunlight in the induction of DNA damage, mutagenesis, and cell death. In fact, the various UV-wavelengths evoke characteristic biological impacts that greatly depend on light absorption of biomolecules, especially DNA, in living organisms, thereby justifying the increasing importance of developing biological sensors for monitoring the harmful impact of solar UV radiation under various environmental conditions. In this review, several types of biosensors proposed for laboratory and field application, that measure the biological effects of the UV component of sunlight, are described. Basically, the applicability of sensors based on DNA, bacteria or even mammalian cells are presented and compared. Data are also presented showing that on using DNA-based sensors, the various types of damage produced differ when this molecule is exposed in either an aqueous buffer or a dry solution. Apart from the data thus generated, the development of novel biosensors could help in evaluating the biological effects of sunlight on the environment. They also emerge as alternative tools for using live animals in the search for protective sunscreen products.

  3. A private ultraviolet channel in visual communication.

    Science.gov (United States)

    Cummings, Molly E; Rosenthal, Gil G; Ryan, Michael J

    2003-05-07

    Although private communication is considered an important diversifying force in evolution, there is little direct behavioural evidence to support this notion. Here, we show that ultraviolet (UV) signalling in northern swordtails (Xiphophorus) affords a channel for communication that is not accessible to their major predator, Astyanax mexicanus, the Mexican tetra. Laboratory and field behavioural experiments with swordtails (X. nigrensis) and predators (A. mexicanus) demonstrate that male UV ornamentation significantly increases their attractiveness to females but not to this predator, which is less sensitive to UV. UV reflectance among swordtail species correlates positively with tetra densities across habitats, and visual contrast estimates suggest that UV signals are highly conspicuous to swordtails in their natural environment. Cross-species comparisons also support the hypothesis that natural selection drives the use of UV communication. We compared two species, one with high (X. nigrensis) and one with low (X. malinche) Mexican tetra densities. Xiphophorus nigrensis males reflect significantly more UV than X. malinche, exhibit significant UV sexual dimorphism, and UV is a salient component of the sexual communication system. In X. malinche, however, males reflect minimally in the UV, there is no UV sexual dimorphism, and UV does not play a part in its communication system.

  4. Ultraviolet disinfection of treated municipal wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Vander Laan, H; Cairns, B

    1993-12-31

    A wastewater disinfection system developed by a Canadian company, Trojan Technologies Inc., was discussed. Disinfection for pathogen reduction prior to discharge of treated municipal wastewater back into rivers and lakes has been either ignored or treated by the use of chemicals. In 1979 the first pilot ultraviolet (UV) wastewater disinfection system was established. Since then, over 500 municipal UV installations have been commissioned. The largest installation can process 212 million gallons of water per day. The advantages of UV as a disinfectant are: (1) It is more effective than chlorine. (2) There are no mutagenic/carcinogenic byproducts formed with UV. (3) No toxic chemical residuals are discharged. (4) UV is safe to both the operators and the public. (5) It is cost effective. Europe has not been as active in wastewater disinfection as has North America. One result of the absence of wastewater disinfection in Europe is that the Rhine River, for example, carries 50 million salmonella per second. Disinfection of wastewater effluents is, of course, indispensable in protecting our drinking water supply. 2 figs.

  5. Impact of ultraviolet radiation on humans

    International Nuclear Information System (INIS)

    Cesarini, J.P.

    2001-01-01

    Solar radiation, including its ultraviolet (UV) components is a key factor in life on Earth. While small quantities of UV are beneficial for people (for example, through the production of vitamin D), the considerable amount to which people sometimes expose themselves may have extremely noxious effects including actinic erythema, sunburn, photo-induced diseases, photo-worsened diseases, actinic ageing and skin cancers. Since the last century, human exposure to UV has increased either by social-behaviour modifications, or by anthropogenic disruption to the environment through, among other things, industrial development. The World Health Organisation's (WHO) INTERSUN programme has several components: action for reconstruction of the ozone layer through, for example, preventing dumping of chlorofluorocarbons; creation and popularisation of a global UV index; prevention campaigns underlining the risks from UV exposure including dissemination of information to daily newspapers. These are all aimed at reducing the amount of UV radiation that people receive. In addition the WHO advises against exposure to UV artificial sources to reduce overall the quantity of UV received. (author)

  6. Impact of ultraviolet radiation on humans

    Energy Technology Data Exchange (ETDEWEB)

    Cesarini, J.P. [Laboratoire de Recherche sur les Tumeurs de la Peau Humaine, INSERM, Paris (France)

    2001-07-01

    Solar radiation, including its ultraviolet (UV) components is a key factor in life on Earth. While small quantities of UV are beneficial for people (for example, through the production of vitamin D), the considerable amount to which people sometimes expose themselves may have extremely noxious effects including actinic erythema, sunburn, photo-induced diseases, photo-worsened diseases, actinic ageing and skin cancers. Since the last century, human exposure to UV has increased either by social-behaviour modifications, or by anthropogenic disruption to the environment through, among other things, industrial development. The World Health Organisation's (WHO) INTERSUN programme has several components: action for reconstruction of the ozone layer through, for example, preventing dumping of chlorofluorocarbons; creation and popularisation of a global UV index; prevention campaigns underlining the risks from UV exposure including dissemination of information to daily newspapers. These are all aimed at reducing the amount of UV radiation that people receive. In addition the WHO advises against exposure to UV artificial sources to reduce overall the quantity of UV received. (author)

  7. Extreme ultraviolet observations of coronal holes. II

    International Nuclear Information System (INIS)

    Bohlin, J.D.; Sheeley, N.R. Jr.

    1978-01-01

    Extreme-ultraviolet Skylab and ground-based solar magnetic field data have been combined to study the origin and evolution of coronal holes. It is shown that holes exist only within the large-scale unipolar magnetic cells into which the solar surface is divided at any given time. A well-defined boundary zone usually exists between the edge of a hole and the neutral line which marks the edge of its magnetic cell. This boundary zone is the region across which a cell is connected by magnetic arcades with adjacent cells of opposite polarity. Three pieces of observational evidence are offered to support the hypothesis that the magnetic lines of force from a hole are open. Kitt Peak magnetograms are used to show that, at least on a relative scale, the average field strengths within holes are quite variable, but indistinguishable from the field strengths in other quiet parts of the Sun's surface. Finally it is shown that the large, equatorial holes characteristic of the declining phase of the last solar cycle during Skylab (1973-74) were all formed as a result of the mergence of bipolar magnetic regions (BMR's), confirming an earlier hypothesis by Timothy et al. (1975). Systematic application of this model to the different aspects of the solar cycle correctly predicts the occurrence of both large, equatorial coronal holes (the 'M-regions' which cause recurrent geomagnetic storms) and the polar cap holes. (Auth.)

  8. Ultraviolet-Absorption Spectroscopic Biofilm Monitor

    Science.gov (United States)

    Micheels, Ronald H.

    2004-01-01

    An ultraviolet-absorption spectrometer system has been developed as a prototype instrument to be used in continuous, real-time monitoring to detect the growth of biofilms. Such monitoring is desirable because biofilms are often harmful. For example, biofilms in potable-water and hydroponic systems act as both sources of pathogenic bacteria that resist biocides and as a mechanism for deterioration (including corrosion) of pipes. Biofilms formed from several types of hazardous bacteria can thrive in both plant-growth solutions and low-nutrient media like distilled water. Biofilms can also form in condensate tanks in air-conditioning systems and in industrial heat exchangers. At present, bacteria in potable-water and plant-growth systems aboard the space shuttle (and previously on the Mir space station) are monitored by culture-plate counting, which entails an incubation period of 24 to 48 hours for each sample. At present, there are no commercially available instruments for continuous monitoring of biofilms in terrestrial or spaceborne settings.

  9. Coral skeletons defend against ultraviolet radiation.

    Directory of Open Access Journals (Sweden)

    Ruth Reef

    Full Text Available BACKGROUND: Many coral reef organisms are photosynthetic or have evolved in tight symbiosis with photosynthetic symbionts. As such, the tissues of reef organisms are often exposed to intense solar radiation in clear tropical waters and have adapted to trap and harness photosynthetically active radiation (PAR. High levels of ultraviolet radiation (UVR associated with sunlight, however, represent a potential problem in terms of tissue damage. METHODOLOGY/PRINCIPAL FINDINGS: By measuring UVR and PAR reflectance from intact and ground bare coral skeletons we show that the property of calcium carbonate skeletons to absorb downwelling UVR to a significant extent, while reflecting PAR back to the overlying tissue, has biological advantages. We placed cnidarians on top of bare skeletons and a UVR reflective substrate and showed that under ambient UVR levels, UVR transmitted through the tissues of cnidarians placed on top of bare skeletons were four times lower compared to their counterparts placed on a UVR reflective white substrate. In accordance with the lower levels of UVR measured in cnidarians on top of coral skeletons, a similar drop in UVR damage to their DNA was detected. The skeletons emitted absorbed UVR as yellow fluorescence, which allows for safe dissipation of the otherwise harmful radiation. CONCLUSIONS/SIGNIFICANCE: Our study presents a novel defensive role for coral skeletons and reveals that the strong UVR absorbance by the skeleton can contribute to the ability of corals, and potentially other calcifiers, to thrive under UVR levels that are detrimental to most marine life.

  10. Reflective masks for extreme ultraviolet lithography

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Khanh Bao [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    Extreme ultraviolet lithographic masks are made by patterning multilayer reflective coatings with high normal incidence reflectivity. Masks can be patterned by depositing a patterned absorber layer above the coating or by etching the pattern directly into the coating itself. Electromagnetic simulations showed that absorber-overlayer masks have superior imaging characteristics over etched masks (less sensitive to incident angles and pattern profiles). In an EUVL absorber overlayer mask, defects can occur in the mask substrate, reflective coating, and absorber pattern. Electromagnetic simulations showed that substrate defects cause the most severe image degradation. A printability study of substrate defects for absorber overlayer masks showed that printability of 25 nm high substrate defects are comparable to defects in optical lithography. Simulations also indicated that the manner in which the defects are covered by multilayer reflective coatings can affect printability. Coverage profiles that result in large lateral spreading of defect geometries amplify the printability of the defects by increasing their effective sizes. Coverage profiles of Mo/Si coatings deposited above defects were studied by atomic force microscopy and TEM. Results showed that lateral spread of defect geometry is proportional to height. Undercut at defect also increases the lateral spread. Reductions in defect heights were observed for 0.15 μm wide defect lines. A long-term study of Mo/Si coating reflectivity revealed that Mo/Si coatings with Mo as the top layer suffer significant reductions in reflectivity over time due to oxidation.

  11. Deuterium abundance, from ultraviolet to visible

    International Nuclear Information System (INIS)

    Hebrard, Guillaume

    2000-01-01

    In the frame of the standard Big Bang model, the primordial abundance of deuterium is the most sensitive to the baryonic density of the Universe. It was synthesized only during the primordial nucleosynthesis few minutes after the Big Bang and no other standard mechanism is able to produce any further significant amount. On the contrary, since deuterium is burned up within stars, its abundance D/H decreases along cosmic evolution. Thus, D/H measurements constrain Big Bang and galactic chemical evolution models. There are three samples of deuterium abundances: primordial, proto-solar and interstellar. Each of them is representative of a given epoch, respectively about 15 Gyrs past, 4.5 Gyrs past and present epoch. Although the evolution of the deuterium abundance seems to be qualitatively understood, the measurements show some dispersion. Present thesis works are linked to deuterium interstellar abundance measurements. Such measurements are classically obtained from spectroscopic observations of the hydrogen and deuterium Lyman series in absorption in the ultraviolet spectral range, using space observatories. Results presented here were obtained with the Hubble Space Telescope and FUSE, which has recently been launched. Simultaneously, a new way to observe deuterium has been proposed, in the visible spectral range from ground-based telescopes. This has led to the first detections and the identification of the deuterium Balmer series, in emission in HII regions, using CFHT and VLT telescopes. (author) [fr

  12. Control of zebra mussels with ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, D.P.

    1998-07-01

    This paper presents the results of research on the effects of low and medium pressure ultraviolet (UV) radiation on zebra mussel mortality carried out between 1992 and 1995. An initial 1992 study, carried out by Aquatic Sciences (ASI), showed that flow-through UV systems have the ability to kill zebra mussels and prevent them from attaching to downstream surfaces. However, this work did not include expanded testing to determine the limitations of UV radiation at higher flow rates or to further define effective working parameters. The 1994 study was carried out at the Lennox Thermal Generating Station (TGS) of Ontario Hydro in Kingston, Ontario. This study involved the testing of two open channel UV systems (medium and low pressure) in an effort to determine flow rates and volumes for which UV disinfection would be effective and practical for the prevention of zebra mussel infestation. It was recommended that medium pressure (MP) and low pressure (LP) UV systems be tested for their ability to control downstream settlement of zebra mussels, in flow-through trials.

  13. Coherence techniques at extreme ultraviolet wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chang [Univ. of California, Berkeley, CA (United States)

    2002-01-01

    The renaissance of Extreme Ultraviolet (EUV) and soft x-ray (SXR) optics in recent years is mainly driven by the desire of printing and observing ever smaller features, as in lithography and microscopy. This attribute is complemented by the unique opportunity for element specific identification presented by the large number of atomic resonances, essentially for all materials in this range of photon energies. Together, these have driven the need for new short-wavelength radiation sources (e.g. third generation synchrotron radiation facilities), and novel optical components, that in turn permit new research in areas that have not yet been fully explored. This dissertation is directed towards advancing this new field by contributing to the characterization of spatial coherence properties of undulator radiation and, for the first time, introducing Fourier optical elements to this short-wavelength spectral region. The first experiment in this dissertation uses the Thompson-Wolf two-pinhole method to characterize the spatial coherence properties of the undulator radiation at Beamline 12 of the Advanced Light Source. High spatial coherence EUV radiation is demonstrated with appropriate spatial filtering. The effects of small vertical source size and beamline apertures are observed. The difference in the measured horizontal and vertical coherence profile evokes further theoretical studies on coherence propagation of an EUV undulator beamline. A numerical simulation based on the Huygens-Fresnel principle is performed.

  14. Ultraviolet spectra of DA white dwarfs

    International Nuclear Information System (INIS)

    Nelan, E.P.

    1985-01-01

    Using the International Ultraviolet Explorer (IUE) satellite, observations of cool to moderately warm DA white dwarfs showed the presence of broad absorption features at lambda 1400 and 1600. The lambda 1600 feature is prominent for T/sub eff/ 0 K and the lambda 1400 feature is visible up to about T/sub eff/ = 18,000 0 K. Proposed mechanisms for absorption at lambda 1400 have included a Si V doublet, H 2 Lyman bands, and the Call ionization edge at lambda 1420. It was recently suggested that the lambda 1600 feature is due to the photoionization edge of Mg I at lambda 1625. None of these has been able to explain all of the observations without invoking some quite unconventional circumstances. On the basis of computer models, this thesis proposes that the absorption in both cases is due to perturbations of the energy level structure of neutral hydrogen atoms undergoing collisions. The lambda 1600 feature is due to absorption by the hydrogen quasi-molecule while that at lambda 1400 arises from a ground state transition of the hydrogen quasi-molecule ion

  15. Surprise Ultraviolet Party in the Sky

    Science.gov (United States)

    2005-01-01

    Galaxies aren't the only objects filling up the view of NASA's Galaxy Evolution Explorer. Since its launch in 2003, the space telescope -- originally designed to observe galaxies across the universe in ultraviolet light -- has discovered a festive sky blinking with flaring and erupting stars, as well as streaking asteroids, satellites and space debris. A group of six streaking objects -- the identities of which remain unknown -- can be seen here flying across the telescope's sight in this sped-up movie. The two brightest objects appear to perform a sharp turn then travel in the reverse direction. This illusion is most likely the result of the Galaxy Evolution Explorer overtaking the objects as it orbits around Earth. Careful inspection reveals four additional faint objects with the same timing and behavior. These faint objects are easiest to see during the retrograde portion of their paths. Three appear between the two bright sources, and one is above them, near the edge of the field of view. These bonus objects are being collected in to public catalogues for other astronomers to study.

  16. Ultraviolet light imaging technology and applications

    Science.gov (United States)

    Yokoi, Takane; Suzuki, Kenji; Oba, Koichiro

    1991-06-01

    Demands on the high-quality imaging in ultraviolet (UV) light region have been increasing recently, especially in fields such as forensic investigations, laser experiments, spent fuel identification, and so on. Important requirements on the UV imaging devices in such applications are high sensitivity, excellent solar blindness, and small image distortion, since the imaging of very weak UV images are usually carried out under natural sunlight or room illuminations and the image data have to be processed to produce useful two-dimensional quantitative data. A new photocathode has been developed to meet these requirements. It is specially made of RbTe on a sapphire window and its quantum efficiency is as high as 20% with the solar blindness of 10,000. The tube is specially designed to meet UV light optics and to minimize image distortion. It has an invertor type image intensifier tube structure and intensifies the incident UV light up to approximately 10,000 times. The distortion of the output image is suppressed less than 1.8%, because of a specially designed electron optic lens system. The device has shown excellent results in the observation of such objects as fingerprints and footprints in forensic investigations, the Cherenkov light produced by the spent fuels stored in a cooling water pool in the nuclear power station, and UV laser beam path in excimer laser experiments. Furthermore, many other applications of the UV light imaging will be expected in various fields such as semiconductors, cosmetics, and electrical power.

  17. Tomographic extreme-ultraviolet spectrographs: TESS.

    Science.gov (United States)

    Cotton, D M; Stephan, A; Cook, T; Vickers, J; Taylor, V; Chakrabarti, S

    2000-08-01

    We describe the system of Tomographic Extreme Ultraviolet (EUV) SpectrographS (TESS) that are the primary instruments for the Tomographic Experiment using Radiative Recombinative Ionospheric EUV and Radio Sources (TERRIERS) satellite. The spectrographs were designed to make high-sensitivity {80 counts/s)/Rayleigh [one Rayleigh is equivalent to 10(6) photons/(4pi str cm(2)s)}, line-of-sight measurements of the oi 135.6- and 91.1-nm emissions suitable for tomographic inversion. The system consists of five spectrographs, four identical nightglow instruments (for redundancy and added sensitivity), and one instrument with a smaller aperture to reduce sensitivity and increase spectral resolution for daytime operation. Each instrument has a bandpass of 80-140 nm with approximately 2- and 1-nm resolution for the night and day instruments, respectively. They utilize microchannel-plate-based two-dimensional imaging detectors with wedge-and-strip anode readouts. The instruments were designed, fabricated, and calibrated at Boston University, and the TERRIERS satellite was launched on 18 May 1999 from Vandenberg Air Force Base, California.

  18. Effects of near ultraviolet and green radiations on plant growth

    Energy Technology Data Exchange (ETDEWEB)

    Klein, R.M.; Edsall, P.C.; Gentile, A.C.

    1965-01-01

    Selective removal of near ultraviolet and green wavelengths from white light permitted enhanced growth of marigold, tomato, corn, and Impatiens plants, Chlamydomonas cells and the mycelium of Sordaria. Additions of near ultraviolet and green radiations caused repressions in the growth of marigold and Sordaria. These wavelengths do not alter the oxidative mechanisms of mitochondria, intact algal cells or marigold leaf tissues. The capacity for chlorophyll and carotenoid synthesis by Euglena cells was unaffected by these wavelengths. 23 references, 2 figures, 4 tables.

  19. Effect of ultraviolet rays in low temperature Si02 deposition

    International Nuclear Information System (INIS)

    Calix, V.M.; Peccoud, L.; Chevallier, M.

    1976-09-01

    Vitreous silicon dioxide films have been prepared on silicon wafers by the oxidation of SiH 2 at temperature below 360 deg C. In this experiment the samples were exposed to ultraviolet rays during deposition process. Results show that there is marked effect on the deposition rate which in turn is temperature dependent. The physical characteristics between the normal and ultraviolet-enhanced deposition show an increase of minute nodules of the latter

  20. Application of ultraviolet and infrared radiation in food

    OpenAIRE

    D Jafarpour; M Alizadeh; F Siamak

    2018-01-01

    BACKGROUND: There are many uses of radiation in the food industry. Radiation can be considered as one of the new processes and usage of it can offer new features of food. This process in most food doesn’t leave any physical or sensory changes. Therefore, in this review article, the application of ultraviolet and infrared radiation in food was studied. Methods: Search by the keywords “Ultraviolet Radiation Infrared Radiation Food” in databases Pubmed, Scopus and Web of Sci...

  1. Translation invariance, commutation relations and ultraviolet/infrared mixing

    International Nuclear Information System (INIS)

    Galluccio, Salvatore; Lizzi, Fedele; Vitale, Patrizia

    2009-01-01

    We show that the Ultraviolet/Infrared mixing of noncommutative field theories with the Groenewold-Moyal product, whereby some (but not all) ultraviolet divergences become infrared, is a generic feature of translationally invariant associative products. We find, with an explicit calculation that the phase appearing in the nonplanar diagrams is the one given by the commutator of the coordinates, the semiclassical Poisson structure of the non commutative spacetime. We do this with an explicit calculation for represented generic products.

  2. Ocular ultraviolet radiation exposure of welders.

    Science.gov (United States)

    Tenkate, Thomas D

    2017-05-01

    I read with interest a recent paper in your journal by Slagor et al on the risk of cataract in relation to metal arc welding (1). The authors highlight that even though welders are exposed to substantial levels of ultraviolet radiation (UVR), "no studies have reported data on how much UVR welders' eyes are exposed to during a working day. Thus, we do not know whether welders are more or less exposed to UVR than outdoor workers" (1, p451). Undertaking accurate exposure assessment of UVR from welding arcs is difficult, however, two studies have reported ocular/facial UVR levels underneath welding helmets (2, 3). In the first paper, UVR levels were measured using polysulphone film dosimeters applied to the cheeks of a patient who suffered from severe facial dermatitis (2). UVR levels of four times the American Conference of Governmental Industrial Hygienists (ACGIH) maximum permissible exposure (MPE) (4) were measured on the workers left cheek and nine times the MPE on the right cheek. The authors concluded that the workers dermatitis was likely to have been due to the UVR exposure received during welding. In the other paper, a comprehensive exposure assessment of personal UVR exposure of workers in a welding environment was reported (3). The study was conducted at a metal fabrication workshop with participants being welders, boilermakers and non-welders (eg, supervisors, fitters, machinists). Polysulphone film dosimeters were again used to measure UVR exposure of the workers, with badges worn on the clothing of workers (in the chest area), on the exterior of welding helmets, attached to 11 locations on the inside of welding helmets, and on the bridge and side-shields of safety spectacles. Dosimeters were also attached to surfaces throughout the workshop to measure ambient UVR levels. For welding subjects, mean 8-hour UVR doses within the welding helmets ranged from around 9 mJ/cm 2 (3×MPE) on the inside of the helmets to around 15 mJ/cm 2 (5×MPE) on the headband (a

  3. Effect of ultraviolet irradiation on mast cell-deficient W/Wv mice

    International Nuclear Information System (INIS)

    Ikai, K.; Danno, K.; Horio, T.; Narumiya, S.

    1985-01-01

    The effect of UV irradiation on the skin was investigated in (WB-W/+) X (C57BL/6J-Wv/+)F1-W/Wv mice, which are genetically deficient in tissue mast cells. Their congenic littermates (+/+) and normal albino mice (ICR or BALB/c) were used as controls. Mice were irradiated with 500 mJ/cm2 of UVB and the increment of ear thickness was measured before and 6, 12, and 24 h after irradiation. Ear swelling in W/Wv mice at 12 and 24 h after irradiation was significantly smaller than that in +/+ and ICR mice. In contrast, the number of sunburn cells formed 24 h after UVB irradiation (200 or 500 mJ/cm2) was similar in W/Wv, +/+ and ICR mice. On the other hand, when mice were treated with 8-methoxy-psoralen (0.5%) plus UVA irradiation (4 J/cm2) (topical PUVA), ears of W/Wv and BALB/c mice, which were both white in color, were thickened similarly 72 h after treatment, but less swelling was observed in +/+ mice, which were black in skin color. The amount of prostaglandin D2 (PGD2) in ears, determined by radioimmunoassay specific for PGD2, was elevated 3-fold in +/+ and ICR mice at 3 h after irradiation with 500 mJ/cm2 of UVB in comparison with basal level without irradiation. However, such elevation was not observed in W/Wv mice. These results suggest that mast cells play an important role in UVB-induced inflammation, and PGs from mast cells are responsible at least in part for the development of this reaction. However, neither mast cells nor PGs contribute to the sunburn cell formation and ear swelling response by PUVA treatment

  4. Making Ultraviolet Spectro-Polarimetry Polarization Measurements with the MSFC Solar Ultraviolet Magnetograph Sounding Rocket

    Science.gov (United States)

    West, Edward; Cirtain, Jonathan; Kobayashi, Ken; Davis, John; Gary, Allen

    2011-01-01

    This paper will describe the Marshall Space Flight Center's Solar Ultraviolet Magnetograph Investigation (SUMI) sounding rocket program. This paper will concentrate on SUMI's VUV optics, and discuss their spectral, spatial and polarization characteristics. While SUMI's first flight (7/30/2010) met all of its mission success criteria, there are several areas that will be improved for its second and third flights. This paper will emphasize the MgII linear polarization measurements and describe the changes that will be made to the sounding rocket and how those changes will improve the scientific data acquired by SUMI.

  5. Ultraviolet photometry from the Orbiting Astronomical Observatory. XXXII - An atlas of ultraviolet stellar spectra

    Science.gov (United States)

    Code, A. D.; Meade, M. R.

    1979-01-01

    Ultraviolet stellar fluxes are presented in graphs and tables for 164 bright stars in the spectral region from 1200 to 3600 A. The spectra represent a subset of OAO 2 spectrometer data on file at the National Space Science Data Center. The monochromatic flux is given in units of erg per (sq cm-s-A) with a spectral resolution of about 22 A in the region from 3600 to 1850 A and of approximately 12 A in the region from 1850 to 1160 A.

  6. Ultraviolet Imaging Telescope images of the reflection nebula NGC 7023 - Derivation of ultraviolet scattering properties of dust grains

    Science.gov (United States)

    Witt, Adolf N.; Petersohn, Jens K.; Bohlin, Ralph C.; O'Connell, Robert W.; Roberts, Morton S.; Smith, Andrew M.; Stecher, Theodore P.

    1992-01-01

    The Ultraviolet Imaging Telescope as part of the Astro-1 mission, was used to obtain high-resolution surface brightness distribution data in six ultraviolet wavelength bands for the bright reflection nebula NGC 7023. From the quantitative comparison of the measured surface brightness gradients ratios of nebular to stellar flux, and detail radial surface brightness profiles with corresponding data from the visible, two major conclusions results: (1) the scattering in the near- and far-ultraviolet in this nebula is more strongly forward-directed than in the visible; (2) the dust albedo in the ultraviolet for wavelengths not less than 140 nm is identical to that in the visible, with the exception of the 220 nm bump in the extinction curve. In the wavelengths region of the bump, the albedo is reduced by 25 to 30 percent in comparison with wavelengths regions both shorter and longer. This lower albedo is expected, if the bump is a pure absorption feature.

  7. Effect of Natural Intensities of Visible and Ultraviolet Radiation on Epidermal Ultraviolet Screening and Photosynthesis in Grape Leaves

    Czech Academy of Sciences Publication Activity Database

    Kolb, Ch.; Kasel, M.; Kopecký, Jiří; ZOTZ, G.; Riederer, M.; Pfundel, E.

    č. 127 (2001), s. 863-875 ISSN 0032-0889 Institutional research plan: CEZ:AV0Z5020903 Keywords : natural intensities * visible * ultraviolet Subject RIV: CE - Biochemistry Impact factor: 5.105, year: 2001

  8. Photoreactivation of Pseudomonas cepacia after ultraviolet exposure: a potential source of contamination in ultraviolet-treated waters

    International Nuclear Information System (INIS)

    Carson, L.A.; Petersen, N.J.

    1975-01-01

    Cells of a naturally occurring strain of Pseudomonas cepacia grown in distilled water were exposed to ultraviolet radiation. Irradiated samples incubated on membrane filters or in fluid recovery media in the absence of light showed no evidence of dark repair mechanisms. When samples were exposed to fluorescent light ranging from 50 to 950 foot candles (538 to 10,222 lux) of illumination, apparent photo-induced repair of ultraviolet injury resulted in 1- to 4-log increases in viable cells recovered

  9. ULTRAVIOLET DISCOVERIES AT ASTEROID (21) LUTETIA BY THE ROSETTA ALICE ULTRAVIOLET SPECTROGRAPH

    International Nuclear Information System (INIS)

    Stern, S. A.; Parker, J. Wm.; Steffl, A.; Birath, E.; Graps, A.; Feldman, P. D.; Weaver, H. A.; A'Hearn, M. F.; Feaga, L.; Bertaux, J.-L.; Slater, D. C.; Versteeg, M.; Scherrer, J. R.; Cunningham, N.

    2011-01-01

    The NASA Alice ultraviolet (UV) imaging spectrograph on board the ESA Rosetta comet orbiter successfully conducted a series of flyby observations of the large asteroid (21) Lutetia in the days surrounding Rosetta's closest approach on 2010 July 10. Observations included a search for emission lines from gas, and spectral observations of the Lutetia's surface reflectance. No emissions from gas around Lutetia were observed. Regarding the surface reflectance, we found that Lutetia has a distinctly different albedo and slope than both the asteroid (2867) Steins and Earth's moon, the two most analogous objects studied in the far ultraviolet (FUV). Further, Lutetia's ∼10% geometric albedo near 1800 A is significantly lower than its 16%-19% albedo near 5500 A. Moreover, the FUV albedo shows a precipitous drop (to ∼4%) between 1800 A and 1600 A, representing the strongest spectral absorption feature observed in Lutetia's spectrum at any observed wavelength. Our surface reflectance fits are not unique but are consistent with a surface dominated by an EH5 chondrite, combined with multiple other possible surface constituents, including anorthite, water frost, and SO 2 frost or a similar mid-UV absorber. The water frost identification is consistent with some data sets but inconsistent with others. The anorthite (feldspar) identification suggests that Lutetia is a differentiated body.

  10. An evaluation of PUVA-therapy for alopecia areata

    NARCIS (Netherlands)

    van der Schaar, W. W.; Sillevis Smith, J. H.

    1984-01-01

    30 patients with alopecia areata were treated with 8-methoxypsoralen orally combined with whole body UVA exposure. 9 patients showed more than 60% regrowth of hair, 8 of them had recurrences of hair loss within a mean time of 7.7 months. No selecting criteria could be found prophesying good results

  11. Ultraviolet spectral reflectance of carbonaceous materials

    Science.gov (United States)

    Applin, Daniel M.; Izawa, Matthew R. M.; Cloutis, Edward A.; Gillis-Davis, Jeffrey J.; Pitman, Karly M.; Roush, Ted L.; Hendrix, Amanda R.; Lucey, Paul G.

    2018-06-01

    A number of planetary spacecraft missions have carried instruments with sensors covering the ultraviolet (UV) wavelength range. However, there exists a general lack of relevant UV reflectance laboratory data to compare against these planetary surface remote sensing observations in order to make confident material identifications. To address this need, we have systematically analyzed reflectance spectra of carbonaceous materials in the 200-500 nm spectral range, and found spectral-compositional-structural relationships that suggest this wavelength region could distinguish between otherwise difficult-to-identify carbon phases. In particular (and by analogy with the infrared spectral region), large changes over short wavelength intervals in the refractive indices associated with the trigonal sp2π-π* transition of carbon can lead to Fresnel peaks and Christiansen-like features in reflectance. Previous studies extending to shorter wavelengths also show that anomalous dispersion caused by the σ-σ* transition associated with both the trigonal sp2 and tetrahedral sp3 sites causes these features below λ = 200 nm. The peak wavelength positions and shapes of π-π* and σ-σ* features contain information on sp3/sp2, structure, crystallinity, and powder grain size. A brief comparison with existing observational data indicates that the carbon fraction of the surface of Mercury is likely amorphous and submicroscopic, as is that on the surface of the martian satellites Phobos and Deimos, and possibly comet 67P/Churyumov-Gerasimenko, while further coordinated observations and laboratory experiments should refine these feature assignments and compositional hypotheses. The new laboratory diffuse reflectance data reported here provide an important new resource for interpreting UV reflectance measurements from planetary surfaces throughout the solar system, and confirm that the UV can be rich in important spectral information.

  12. Ultraviolet radiation exposure from UV-transilluminators.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Jahangir-Blourchian, Mahdi

    2005-10-01

    UV-transilluminators use ultraviolet radiation (UVR) to visualize proteins, DNA, RNA, and their precursors in a gel electrophoresis procedure. This study was initiated to evaluate workers' exposure to UVR during their use of UV-transilluminators. The levels of irradiance of UV-A, UV-B, and UV-C were determined for 29 UV-transilluminators at arbitrary measuring locations of 6, 25, 62, and 125 cm from the center of the UV-transilluminator's filter surface in the direction of the operator's head. The operators (faculty, research staff, and graduate students) worked within 62 cm of the transilluminators, with most subjects commonly working at time ranged from 1 to 60 min. Actinic hazard (effective irradiance level of UVR) was also determined for three representative UV-transilluminators at arbitrary measuring locations of 2.5, 5, 10, 15, 20, 30, 40, and 50 cm from these sets' filter surface in the direction of the operator's head. The allowable exposure time for these instruments was less than 20 sec within 15 cm, less than 35 sec within 25 cm, and less than 2 min within 50 cm from the UV-transilluminators' filter surface. The results of this study suggest that the use of UV-transilluminators exposes operators to levels of UVR in excess of exposure guidelines. It is recommended that special safety training be provided for the affected employees and that exposure should be controlled by one or the combination of automation, substitution, isolation, posted warning signs, shielding, and/or personal protective equipment.

  13. Interstellar Silicon Depletion and the Ultraviolet Extinction

    Science.gov (United States)

    Mishra, Ajay; Li, Aigen

    2018-01-01

    Spinning small silicate grains were recently invoked to account for the Galactic foreground anomalous microwave emission. These grains, if present, will absorb starlight in the far ultraviolet (UV). There is also renewed interest in attributing the enigmatic 2175 Å interstellar extinction bump to small silicates. To probe the role of silicon in the UV extinction, we explore the relations between the amount of silicon required to be locked up in silicates [Si/H]dust and the 2175 Å bump or the far-UV extinction rise, based on an analysis of the extinction curves along 46 Galactic sightlines for which the gas-phase silicon abundance [Si/H]gas is known. We derive [Si/H]dust either from [Si/H]ISM - [Si/H]gas or from the Kramers- Kronig relation which relates the wavelength-integrated extinction to the total dust volume, where [Si/H]ISM is the interstellar silicon reference abundance and taken to be that of proto-Sun or B stars. We also derive [Si/H]dust from fi�tting the observed extinction curves with a mixture of amorphous silicates and graphitic grains. We fi�nd that in all three cases [Si/H]dust shows no correlation with the 2175 Å bump, while the carbon depletion [C/H]dust tends to correlate with the 2175 Å bump. This supports carbon grains instead of silicates as the possible carrier of the 2175 Å bump. We also �find that neither [Si/H]dust nor [C/H]dust alone correlates with the far-UV extinction, suggesting that the far-UV extinction is a combined effect of small carbon grains and silicates.

  14. GaN membrane MSM ultraviolet photodetectors

    Science.gov (United States)

    Muller, A.; Konstantinidis, G.; Kostopoulos, A.; Dragoman, M.; Neculoiu, D.; Androulidaki, M.; Kayambaki, M.; Vasilache, D.; Buiculescu, C.; Petrini, I.

    2006-12-01

    GaN exhibits unique physical properties, which make this material very attractive for wide range of applications and among them ultraviolet detection. For the first time a MSM type UV photodetector structure was manufactured on a 2.2 μm. thick GaN membrane obtained using micromachining techniques. The low unintentionally doped GaN layer structure was grown by MOCVD on high resistivity (ρ>10kΩcm) oriented silicon wafers, 500μm thick. The epitaxially grown layers include a thin AlN layer in order to reduce the stress in the GaN layer and avoid cracking. Conventional contact lithography, e-gun Ni/Au (10nm /200nm) evaporation and lift-off techniques were used to define the interdigitated Schottky metalization on the top of the wafer. Ten digits with a width of 1μm and a length of 100μm were defined for each electrode. The distance between the digits was also 1μm. After the backside lapping of the wafer to a thickness of approximately 150μm, a 400nm thick Al layer was patterned and deposited on the backside, to be used as mask for the selective reactive ion etching of silicon. The backside mask, for the membrane formation, was patterned using double side alignment techniques and silicon was etched down to the 2.2μm thin GaN layer using SF 6 plasma. A very low dark current (30ρA at 3V) was obtained. Optical responsivity measurements were performed at 1.5V. A maximum responsivity of 18mA/W was obtained at a wavelength of 370nm. This value is very good and can be further improved using transparent contacts for the interdigitated structure.

  15. Ultraviolet dosimetry using thermoluminescent phosphors - an update

    International Nuclear Information System (INIS)

    Nagpal, J.S.

    1998-04-01

    Intrinsic response of various thermoluminescent (TL) materials such as CaSO 4 (Dy, Eu, Mn, Sm, Tb, or Tm), LiF (Mg, Cu, P), Mg 2 SiO 4 :Tb, CaF 2 :Dy, CaF 2 :Tb, ThO 2 :Tb and Al 2 O 3 (Si, Ti); cathodoluminescent phosphors Y 3 Al 5 O 12 :Ce, Y 3 Al 5 O 12 :Tb and Y(V,P)O 4 :Eu; and fluorescent lamp phosphors calcium halophosphate (Mn,Sb) and Ce Mg aluminate (Eu, Tb) to ultraviolet (UV) radiations has been studied. Intrinsic TL response of most of the phosphors is rate (radiant flux) dependent. For the first time, UV response of the materials is reported for a fixed total radiant energy (total UV dose), at a single radiant flux (260 μW.cm -2 ), for an appropriate comparison. A wide range of UV sensitivity is observed. Studies conducted using UV radiation from two unfiltered low pressure mercury lamps show significant differences in glow curves, as compared to those obtained with nearly monochromatic UV radiations. Photons of wavelength 365 nm induce bleaching of TL induced by 254 nm photons, in most of the materials. Sequential/tandem exposures to 254 nm and 365 nm photons have yielded new but alarming results in CaF 2 :Tb. Preferential induction and bleaching of specific TL glow peaks by 365 nm and 254 nm photons are interesting characteristics discovered in CaSO 4 :Eu. Photoluminescence studies of Tb 3+ and Eu 3+ activated phosphors have augmented the inferences drawn from the bleaching effects produced by 365 nm photons. Earlier work carried out on phototransferred thermoluminescence of CaSO 4 :Dy-teflon dosimeters, TLD-100, Mg 2 SiO 4 :Tb and Al 2 O 3 (Si,Ti) has also been reviewed. (author)

  16. Ultraviolet absorption detection of DNA in gels

    International Nuclear Information System (INIS)

    Mahon, A.R.

    1998-01-01

    A method and apparatus for the detection and quantification of large fragments of unlabelled deoxyribonucleic acid (DNA) in agarose gels is presented. The technique is based on ultra-violet (UV) absorption by nucleotides. A deuterium lamp was used to illuminate regions of an electrophoresis gel. As DNA bands passed through the illuminated region of the gel the amount of UV light transmitted was reduced due to DNA absorption. Two detection systems were investigated. In the first system, synthetic chemical vapour deposition (CVD) diamond strip detectors were used to locate regions of DNA in the gels by detecting the transmitted light. CVD diamond has a high indirect band gap of 5.45 eV and is therefore sensitive to UV photons of wavelengths < 224 nm. A number of CVD diamond samples were characterised to investigate their suitability as detectors for this application. The detectors' quantum efficiency, UV response and time response were measured. DNA bands containing as little as 20 ng were detected by the diamond. In a second system, a deuterium lamp was used to illuminate individual sample lanes of an electrophoresis gel via an array of optical fibres. During electrophoresis the regions of DNA were detected with illumination at 260 nm, using a UV-sensitive charge coupled device (CCD). As the absorption coefficient of a DNA sample is approximately proportional to its mass, the technique is inherently quantitative. This system had a detection limit of 0.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. Using this detection technique, the DNA sample remains in its native state. The removal of carcinogenic dyes from the detection procedure greatly reduces associated biological hazards. (author)

  17. Ultraviolet imaging of planetary nebulae with GALEX

    Science.gov (United States)

    Bianchi, Luciana; Thilker, David

    2018-05-01

    Over four hundred Galactic Planetary Nebulae (PNe) have been imaged by GALEX in two ultraviolet (UV) bands, far-UV (FUV, 1344-1786 Å, λ _{eff}= 1528 Å) and near-NUV (NUV, 1771-2831 Å, λ _{eff} = 2271 Å). We present examples of extended PNe, for which UV spectroscopy is also available, to illustrate the variety in UV morphology and color, which reflects ionization conditions. The depth of the GALEX imaging varies from flux ≈ 0.4/5× 10 ^{-18} ergs cm^{-2} s^{-1} Å^{-1} \\square ^'' -1} (FUV/NUV) for exposures of the order of ˜ 100 seconds, typical of the survey with the largest area coverage, to ˜ 0.3/8.3× 10^{-19} ergs cm^{-2} s^{-1} Å^{-1} \\square ^'' -1} (FUV/NUV) for ˜ 1500 sec exposures, typical of the second largest survey (see Bianchi in Astrophys. Space Sci. 320:11, 2009; Bianchi et al. in Adv. Space Res. 53:900, 2014). GALEX broad-band FUV and NUV fluxes include nebular emission lines and in some cases nebular continuum emission. The sensitivity of the GALEX instrument and the low sky background, especially in FUV, enable detection and mapping of very faint ionization regions and fronts, including outermost wisps and bow shocks. The FUV-NUV color of the central star provides a good indication of its T_{eff}, because the GALEX FUV-NUV color is almost reddening-free for Milky Way type dust (Bianchi et al. in Astrophys. J. Suppl. Ser. 230:24, 2017; Bianchi in Astrophys. Space Sci. 335:51, 2011, Bianchi in Astrophys. Space Sci. 354:103, 2014) and it is more sensitive to hot temperatures than optical colors.

  18. Ultraviolet photodissociation dynamics of the benzyl radical.

    Science.gov (United States)

    Song, Yu; Zheng, Xianfeng; Lucas, Michael; Zhang, Jingsong

    2011-05-14

    Ultraviolet (UV) photodissociation dynamics of jet-cooled benzyl radical via the 4(2)B(2) electronically excited state is studied in the photolysis wavelength region of 228 to 270 nm using high-n Rydberg atom time-of-flight (HRTOF) and resonance enhanced multiphoton ionization (REMPI) techniques. In this wavelength region, H-atom photofragment yield (PFY) spectra are obtained using ethylbenzene and benzyl chloride as the precursors of benzyl radical, and they have a broad peak centered around 254 nm and are in a good agreement with the previous UV absorption spectra of benzyl. The H + C(7)H(6) product translational energy distributions, P(E(T))s, are derived from the H-atom TOF spectra. The P(E(T)) distributions peak near 5.5 kcal mol(-1), and the fraction of average translational energy in the total excess energy, , is ∼0.3. The P(E(T))s indicate the production of fulvenallene + H, which was suggested by recent theoretical studies. The H-atom product angular distribution is isotropic, with the anisotropy parameter β ≈ 0. The H/D product ratios from isotope labeling studies using C(6)H(5)CD(2) and C(6)D(5)CH(2) are reasonably close to the statistical H/D ratios, suggesting that the H/D atoms are scrambled in the photodissociation of benzyl. The dissociation mechanism is consistent with internal conversion of the electronically excited benzyl followed by unimolecular decomposition of the hot benzyl radical on the ground state.

  19. Maps of ultraviolet radiation in Costa Rica

    International Nuclear Information System (INIS)

    Wright, Jaime

    2009-01-01

    Ultraviolet radiation (UV) has contributed relatively little energy to the solar spectrum; but is important, because it is biologically active. The software Surfer 8 has created maps designed of the territory of Costa Rica to assess the maximum levels of solar UV radiation on a horizontal plane. The data were used in creating the maps, were predicted at local noon in eighty-three locations scattered across the country, with a spectral atmospheric model which is physically established. The model has used as input data: the date and time, the location identified by latitude, longitude and height of land above sea level, the value of the vertical column ozone, surface albedo and atmospheric turbidity parameters. The estimate differs by 3% of the measurements made in situ, which agrees with the experimental data. The model has used the data estimation of UV radiation, clear sky conditions, which is the condition where you get the maximum energy possible in each locality. This is of fundamental importance when assessing the adverse effects on human health, leads the maximum intensity in this important solar spectrum band. A larger increase of 23% has presented in the UV radiation with altitude obtaining the hills and mountains the highest rates and places located at sea level and the lowest cost, the indices. The annual variation analysis has revealed an increase greater than 27% from the month of lowest UV radiation (December) and the month of greatest UV radiation (April). The issue is of particular interest because of the increasing number of people moving at different times of the year, altitudes over 2000 m altitude, in activities relating to tourism and employment. These individuals are significant increases in levels of UV solar radiation under conditions of clear skies. (author) [es

  20. Ultraviolet signals in birds are special.

    Science.gov (United States)

    Hausmann, Franziska; Arnold, Kathryn E; Marshall, N Justin; Owens, Ian P F

    2003-01-07

    Recent behavioural experiments have shown that birds use ultraviolet (UV)-reflective and fluorescent plumage as cues in mate choice. It remains controversial, however, whether such UV signals play a special role in sexual communication, or whether they are part of general plumage coloration. We use a comparative approach to test for a general association between sexual signalling and either UV-reflective or fluorescent plumage. Among the species surveyed, 72% have UV colours and there is a significant positive association between UV reflectance and courtship displays. Among parrots (Psittaciformes), 68% of surveyed species have fluorescent plumage, and again there is a strong positive association between courtship displays and fluorescence. These associations are not artefacts of the plumage used in courtship displays, being generally more 'colourful' because there is no association between display and colours lacking UV reflectance or fluorescence. Equally, these associations are not phylogenetic artefacts because all results remain unchanged when families or genera, rather than species, are used as independent data points. We also find that, in parrots, fluorescent plumage is usually found adjacent to UV-reflective plumage. Using a simple visual model to examine one parrot, the budgerigar Melopsittacus undulatus, we show that the juxtaposition of UV-reflective and fluorescent plumage leads to a 25-fold increase in chromatic contrast to the budgerigar's visual system. Taken together, these results suggest that signals based on UV contrast are of special importance in the context of active sexual displays. We review briefly six hypotheses on why this may be the case: suitability for short-range signalling; high contrast with backgrounds; invisibility to predators; exploitation of pre-existing sensory biases; advertisement of feather structure; and amplification of behavioural signals.

  1. Ultraviolet Radiations: Skin Defense-Damage Mechanism.

    Science.gov (United States)

    Mohania, Dheeraj; Chandel, Shikha; Kumar, Parveen; Verma, Vivek; Digvijay, Kumar; Tripathi, Deepika; Choudhury, Khushboo; Mitten, Sandeep Kumar; Shah, Dilip

    2017-01-01

    UV-radiations are the invisible part of light spectra having a wavelength between visible rays and X-rays. Based on wavelength, UV rays are subdivided into UV-A (320-400 nm), UV-B (280-320 nm) and UV-C (200-280 nm). Ultraviolet rays can have both harmful and beneficial effects. UV-C has the property of ionization thus acting as a strong mutagen, which can cause immune-mediated disease and cancer in adverse cases. Numbers of genetic factors have been identified in human involved in inducing skin cancer from UV-radiations. Certain heredity diseases have been found susceptible to UV-induced skin cancer. UV radiations activate the cutaneous immune system, which led to an inflammatory response by different mechanisms. The first line of defense mechanism against UV radiation is melanin (an epidermal pigment), and UV absorbing pigment of skin, which dissipate UV radiation as heat. Cell surface death receptor (e.g. Fas) of keratinocytes responds to UV-induced injury and elicits apoptosis to avoid malignant transformation. In addition to the formation of photo-dimers in the genome, UV also can induce mutation by generating ROS and nucleotides are highly susceptible to these free radical injuries. Melanocortin 1 receptor (MC1R) has been known to be implicated in different UV-induced damages such as pigmentation, adaptive tanning, and skin cancer. UV-B induces the formation of pre-vitamin D3 in the epidermal layer of skin. UV-induced tans act as a photoprotection by providing a sun protection factor (SPF) of 3-4 and epidermal hyperplasia. There is a need to prevent the harmful effects and harness the useful effects of UV radiations.

  2. Long-wave UVA radiation excited warm white-light emitting NaGdTiO4: Tm3+/Dy3+/Eu3+ ions tri-doped phosphors: Synthesis, energy transfer and color tunable properties

    International Nuclear Information System (INIS)

    Bharat, L. Krishna; Du, Peng; Yu, Jae Su

    2016-01-01

    NaGdTiO 4 (NGT) phosphors doped with different activator ions (Tm 3+ , Dy 3+ , and Eu 3+ ) were synthesized by a conventional solid-state reaction method in an ambient atmosphere. These phosphors were characterized by scanning electron microscope images, transmission electron microscope images, X-ray diffraction patterns, Fourier transform infrared spectra, and photoluminescence spectra. All the samples were crystallized in an orthorhombic phase with a space group of Pbcm (57). In Tm 3+ /Dy 3+ ions co-doped samples, white-light emission was observed under near-ultraviolet (NUV) excitation. In addition, the energy transfer between Tm 3+ and Dy 3+ ions was proved to be a resonant type via an electric dipole–dipole mechanism and the critical distance of energy transfer was calculated to be 19.91 Å. Furthermore, Tm 3+ /Dy 3+ /Eu 3+ ions tri-doped NGT phosphors demonstrated warm white-light emission by appropriately tuning the activator content, based on the principle of energy transfer. These NUV wavelength excitable phosphors exhibit great potential as a single-phase full-color emitting phosphor for white light-emitting diode applications. - Highlights: • The pebble shaped NaGdTiO 4 particles were prepared by solid-state reaction method. • Tm 3+ and Dy 3+ single doping gives respective blue and cool white light emission. • The Tm 3+ /Dy 3+ ions co-doped samples give CIE values near to standard white light. • Addition of Eu 3+ ions shifts the CIE values towards warm white light region. • This single phase white light emitting phosphors have lower CCT values (<5000 K).

  3. Ultraviolet susceptibility of BCG and virulent tubercle bacilli

    International Nuclear Information System (INIS)

    Riley, R.L.; Knight, M.; Middlebrook, G.

    1976-01-01

    To test the effectiveness of irradiating the upper air of a room with ultraviolet light at reducing the concentration of airborne tubercle bacilli, the susceptibility to the germicidal effects of ultraviolet light, Z, was determined for various mycobacteria. Virulent tubercle bacilli and bacille Calmette-Guerin (BCG) were susceptible to ultraviolet radiation, whereas Mycobacterium phlei had 10 times their resistance (Z, approximately one-tenth that for M. tuberculosis). The effectiveness against BCG of upper air ultraviolet irradiation in a room was tested directly by nebulizing BCG into the air of the room and monitoring its rate of disappearance. With one 17-watt fixture operating, the rate of disappearance increased 6-fold; with 2 fixtures operating (46 watts total), the rate of disappearance increased 9-fold. This implies that under steady-state conditions, the concentrations of airborne organisms with ultraviolet light(s) on would have been one-sixth and one-ninth, respectively. The increase in rate of decay of the airborne organism using 1 fixture was equivalent to 10 air changes per hour, whereas that using 2 fixtures was approximately 25 air changes per hour (range: 18 to 33 air changes per hour). These increments are less than those reported previously for Serratia marcescens, because the Z value for BCG is approximately one-seventh that for serratia. These findings with BCG are believed to be directly applicable to virulent tubercle bacilli

  4. Photochemoprevention of ultraviolet B signaling and photocarcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Afaq, Farrukh [Department of Dermatology, University of Wisconsin, Medical Sciences Center, Room B25, 1300 University Avenue, Madison, WI 53706 (United States); Adhami, Vaqar M. [Department of Dermatology, University of Wisconsin, Medical Sciences Center, Room B25, 1300 University Avenue, Madison, WI 53706 (United States); Mukhtar, Hasan [Department of Dermatology, University of Wisconsin, Medical Sciences Center, Room B25, 1300 University Avenue, Madison, WI 53706 (United States)]. E-mail: hmukhtar@wisc.edu

    2005-04-01

    Exposure to solar radiation, particularly its ultraviolet (UV) B component, has a variety of harmful effects on human health. Some of these effects include sunburn cell formation, basal and squamous cell cancers, melanoma, cataracts, photoaging of the skin, and immune suppression. Amongst these various adverse effects of UV radiation, skin cancer is of the greatest concern. Over the years, changes in lifestyle has led to a significant increase in the amount of UV radiation that people receive, and this consequently has led to a surge in the incidence of skin cancer. The development of skin cancer is a complex multistage phenomenon involving three distinct stages exemplified by initiation, promotion and progression stages. Each of these stages is mediated via alterations in various cellular, biochemical, and molecular changes. Initiation, the first step in the carcinogenesis process is essentially an irreversible step in which genetic alterations occur in genes that ultimately leads to DNA modification and fixation of mutation. Tumor promotion is the essential process in cancer development involving clonal expansion of initiated cells giving rise to pre-malignant and then to malignant lesions, essentially by alterations in signal transduction pathways. Tumor progression involves the conversion of pre-malignant and malignant lesions into an invasive and potentially metastatic malignant tumor. All these processes for skin cancer development involve stimulation of DNA synthesis, DNA damage and proliferation, inflammation, immunosuppression, epidermal hyperplasia, cell cycle dysregulation, depletion of antioxidant defenses, impairment of signal transduction pathways, induction of cyclooxygenase, increase in prostaglandin synthesis, and induction of ornithine decarboxylase. Photochemoprevention has been appreciated as a viable approach to reduce the occurrence of skin cancer and in recent years, the use of agents, especially botanical antioxidants, present in the common

  5. Photochemoprevention of ultraviolet B signaling and photocarcinogenesis

    International Nuclear Information System (INIS)

    Afaq, Farrukh; Adhami, Vaqar M.; Mukhtar, Hasan

    2005-01-01

    Exposure to solar radiation, particularly its ultraviolet (UV) B component, has a variety of harmful effects on human health. Some of these effects include sunburn cell formation, basal and squamous cell cancers, melanoma, cataracts, photoaging of the skin, and immune suppression. Amongst these various adverse effects of UV radiation, skin cancer is of the greatest concern. Over the years, changes in lifestyle has led to a significant increase in the amount of UV radiation that people receive, and this consequently has led to a surge in the incidence of skin cancer. The development of skin cancer is a complex multistage phenomenon involving three distinct stages exemplified by initiation, promotion and progression stages. Each of these stages is mediated via alterations in various cellular, biochemical, and molecular changes. Initiation, the first step in the carcinogenesis process is essentially an irreversible step in which genetic alterations occur in genes that ultimately leads to DNA modification and fixation of mutation. Tumor promotion is the essential process in cancer development involving clonal expansion of initiated cells giving rise to pre-malignant and then to malignant lesions, essentially by alterations in signal transduction pathways. Tumor progression involves the conversion of pre-malignant and malignant lesions into an invasive and potentially metastatic malignant tumor. All these processes for skin cancer development involve stimulation of DNA synthesis, DNA damage and proliferation, inflammation, immunosuppression, epidermal hyperplasia, cell cycle dysregulation, depletion of antioxidant defenses, impairment of signal transduction pathways, induction of cyclooxygenase, increase in prostaglandin synthesis, and induction of ornithine decarboxylase. Photochemoprevention has been appreciated as a viable approach to reduce the occurrence of skin cancer and in recent years, the use of agents, especially botanical antioxidants, present in the common

  6. Disinfection ultraviolet radiation bulk food products

    OpenAIRE

    Семенов, А. А.

    2014-01-01

    В работе представлены результаты обеззараживания сыпучих пищевых продуктов ультрафиолетовым излучением. Предложена технология бактерицидного обеззараживания сыпучих продуктов с размером частиц до 50 мкм. Проведены необходимые расчеты, связанные с дозой облучения, с временем пребывания частиц в зоне облучения и необходимой дозой инактивации в зависимости от вида бактерий. Considered the results of bulk food products disinfection by ultraviolet radiation. The technology bactericidal disinfec...

  7. Solar ultraviolet radiation from cancer induction to cancer prevention: solar ultraviolet radiation and cell biology.

    Science.gov (United States)

    Tuorkey, Muobarak J

    2015-09-01

    Although decades have elapsed, researchers still debate the benefits and hazards of solar ultraviolet radiation (UVR) exposure. On the one hand, humans derive most of their serum 25-hydroxycholecalciferol [25(OH)D3], which has potent anticancer activity, from solar UVB radiation. On the other hand, people are more aware of the risk of cancer incidence associated with harmful levels of solar UVR from daily sunlight exposure. Epidemiological data strongly implicate UV radiation exposure as a major cause of melanoma and other cancers, as UVR promotes mutations in oncogenes and tumor-suppressor genes. This review highlights the impact of the different mutagenic effects of solar UVR, along with the cellular and carcinogenic challenges with respect to sun exposure.

  8. Extreme ultraviolet (EUV) and FUV calibration facility for special sensor ultraviolet limb imager (SSULI)

    Science.gov (United States)

    Boyer, Craig N.; Osterman, Steven N.; Thonnard, Stefan E.; McCoy, Robert P.; Williams, J. Z.; Parker, S. E.

    1994-09-01

    A facility for calibrating far ultraviolet and extreme ultraviolet instruments has recently been completed at the Naval Research Laboratory. Our vacuum calibration vessel is 2-m in length, 1.67-m in diameter, and can accommodate optical test benches up to 1.2-m wide by 1.5-m in length. A kinematically positioned frame with four axis precision pointing capability of 10 microns for linear translation and .01 degrees for rotation is presently used during vacuum optical calibration of SSULI. The chamber was fabricated from 304 stainless steel and polished internally to reduce surface outgassing. A dust-free environment is maintained at the rear of the vacuum chamber by enclosing the 2-m hinged vacuum access door in an 8 ft. by 8 ft. class 100 clean room. Every effort was made to obtain an oil-free environment within the vacuum vessel. Outgassing products are continually monitored with a 1 - 200 amu residual gas analyzer. An oil-free claw and vane pump evacuates the chamber to 10-2 torr through 4 in. diameter stainless steel roughing lines. High vacuum is achieved and maintained with a magnetically levitated 480 l/s turbo pump and a 3000 l/s He4 cryopump. Either of two vacuum monochrometers, a 1-m f/10.4 or a 0.2-m f/4.5 are coaxially aligned with the optical axis of the chamber and are used to select single UV atomic resonance lines from a windowless capillary or penning discharge UV light source. A calibrated channeltron detector is coaxially mounted with the SSULI detector during calibration. All vacuum valves, the cooling system for the cryopump compressor, and the roughing pump are controlled through optical fibers which are interfaced to a computer through a VME board. Optical fibers were chosen to ensure that complete electrical isolation is maintained between the computer and the vacuum system valves-solenoids and relays.

  9. Ultraviolet radiation, measurements and safety evaluations for radiation protection purposes

    International Nuclear Information System (INIS)

    Witew, B.; Fischer, P.G.

    1983-01-01

    In order to evaluate the effects of ultraviolet radiation, one has to study that photobiologically effective radiation which induces a just measurable threshold reaction. For practical radiation protection, one has to determine the permissible duration of exposure at the end of which the threshold reaction is induced. This time limit is derived by means of spectral measurements and determination of radiation intensity. Detrimental photobiological effects can be avoided, and favourable effects optimized, by observing the time limit. Thus these measurements are used to determine the threshold at which the desired effects of ultraviolet radiation will be accompanied by unwanted effects or damage to persons, as for instance in the use of ultraviolet radiation for operating room sterilization, arc welding work, or cosmetic purposes. (orig.) [de

  10. Familial melanoma associated with dominant ultraviolet radiation sensitivity

    International Nuclear Information System (INIS)

    Ramsay, R.G.; Chen, P.; Imray, F.P.; Kidson, C.; Lavin, M.F.; Hockey, A.

    1982-01-01

    Sensitivity to ultraviolet radiation was studied in lymphoblastoid cell lines derived from 32 members of two families with histories of multiple primary melanomas in several generations. As assayed by colony formation in agar or by trypan blue exclusion following irradiation, cellular sensitivity showed a bimodal distribution. All persons with melanoma or multiple moles were in the sensitive group, while some family members exhibited responses similar to those of controls. Cells from four cases of sporadic melanoma showed normal levels of sensitivity. The data are consistent with a dominantly inherited ultraviolet light sensitivity associated with these examples of familial melanoma. Spontaneous and ultraviolet light-induced sister chromatid exchange frequencies were similar to those in control cell lines. No defect in excision repair was detected in any of the above cell lines, but the sensitive group showed postirradiation inhibition of DNA replication intermediate between controls and an excision-deficient xeroderma pigmentosum cell line

  11. Inactivation of oocysts of Cryptosporidium parvum by ultraviolet irradiation

    International Nuclear Information System (INIS)

    Campbell, A.T.; Robertson, L.J.; Snowball, M.R.; Smith, H.V.

    1995-01-01

    Inactivation of oocysts of Cryptosporidium parvum in clean water using a novel design of an ultraviolet disinfection system was assessed by a vital dye assay and by in vitro excystation. The disinfection unit system is designed to expose the oocysts to ultraviolet radiation on two filters, providing a maximum total exposure to ultraviolet radiation of 8748 mW s cm −2 . Results revealed a reduction in oocyst viability of over two logs, indicating that this treatment has exciting potential as an additional treatment for water already treated by conventional methods. However, these data are only preliminary results using one isolate of oocysts and further trials must be conducted before this system could be recommended for use

  12. Sensitivity Calibration of Far-Ultraviolet Imaging Spectrograph

    Directory of Open Access Journals (Sweden)

    I. -J. Kim

    2004-12-01

    Full Text Available We describe the in-flight sensitivity calibration of the Far ultraviolet Imaging Spectrograph (FIMS, also known as SPEAR onboard the first Korean science satellite, STSAT-1, which was launched in September 2003. The sensitivity calibration is based on a comparison of the FIMS observations of the hot white dwarf G191B2B, and two O-type stars Alpha-Cam, HD93521 with the HUT (Hopkins Ultraviolet Telescope observations. The FIMS observations for the calibration targets have been conducted from November 2003 through May 2004. The effective areas calculated from the targets are compared with each other.

  13. Ultraviolet-B lethal damage on Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Degiorgi, C.F.; Fernandez, R.O.; Pizarro, R.A.

    1996-01-01

    Pseudomonas aeruginosa has shown an increased sensitivity compared with that of Escherichia coli and Enterobacter cloacae, when they were exposed to 0.4 kJ/m2 of ultraviolet-B radiation. The rapid decay in cell viability observed in Pseudomonas aeruginosa after the irradiation was influenced by factors such as culture media and the presence of pyocyanine during the irradiation. The radioinduced lethal damage could be prevented by photoreactivating treatment, indicating that pyrimidine dimer formation was the mechanism causing bacterial death. The results indicate that several environmental conditions may act as protective agents against ultraviolet-B-induced damage

  14. Ultraviolet spectrophotometry from Gemini 11 of stars in Orion

    International Nuclear Information System (INIS)

    Morgan, T.H.; Spear, G.G.; Kondo, Y.; Henize, K.G.

    1975-01-01

    Ultraviolet spectrophotometry in the wavelength region 2600--3600 A is reported for the bright early-type stars β, eta, γ, delta, iota, epsilon, sigma, xi, and kappa Ori. The results are in good agreement with other observations, and with the possible exception of the supergiants, are in good agreement with recent line-blanketed model atmospheres. There is evidence that the supergiants possess a small ultraviolet deficiency shortward of 3000 A relative to main-sequence stars of similar spectral type. The most extreme example of this phenomenon is the star kappa Ori

  15. Variations in ultraviolet extinction: effect of polarization revisited

    International Nuclear Information System (INIS)

    Greenberg, J.M.; Chlewicki, G.; Rijksuniversiteit Groningen

    1987-01-01

    The alignment of the particles responsible for the polarization and visual extinction is shown to provide a basis for changing the saturation level of the ultraviolet extinction without changing the particle sizes. If the particles are well aligned, it is predicted that there should be significantly lower extinction in the ultraviolet relative to the visible for stars viewed perpendicular to magnetic-field lines (maximum polarization) as compared with those viewed across the field lines. Preliminary evidence for such an effect is noted in Carina. (author)

  16. An Empirical Ultraviolet Iron Spectrum Template Applicable to Active Galaxies

    DEFF Research Database (Denmark)

    Vestergaard, Marianne; Wilkes, B. J.

    2001-01-01

    Iron emission is often a severe contaminant in optical-ultraviolet spectra of active galaxies. Its presence complicates emission line studies. A viable solution, already successfully applied at optical wavelengths, is to use an empirical iron emission template. We have generated FeII and Fe......III templates for ultraviolet active galaxy spectra based on HST archival 1100 - 3100 A spectra of IZw1. Their application allows fitting and subtraction of the iron emission in active galaxy spectra. This work has shown that in particular CIII] lambda 1909 can be heavily contaminated by other line emission...

  17. Quantum-Gravity Phenomenology of soft ultraviolet/infrared mixing

    International Nuclear Information System (INIS)

    Amelino-Camelia, Giovanni; Loret, Niccolo; Mercati, Flavio

    2010-01-01

    We reexamine the motivation for ultraviolet/infrared mixing in quantum gravity and some of the quantum-spacetime formalizations where it has been found. We then focus on cases in which the infrared manifestations of the mixing are relatively soft, arguing that they can motivate a particularly appealing phenomenology. Among the possible implications for the large-distance behavior of gravity one intriguingly finds a correction with logarithmic dependence on distance. And one can explain in terms of soft ultraviolet/infrared mixing a four-standard-deviation discrepancy that was recently established in the context of studies of cold neutrons.

  18. Effects of gamma irradiation on antioxidants and ultraviolet stabilizers

    International Nuclear Information System (INIS)

    Kawamura, Yoko; Miura, Makiko; Miura, Yukiko; Yamada, Takashi

    1998-01-01

    The effects of gamma irradiation on 18 kinds of antioxidants and 10 kinds of ultraviolet stabilizers, intact or in a polyethylene sheet, were studied. After irradiating at a 30kGy dose, the content of additives themselves did not change and new degradation products were not found. While most antioxidants in polyethylene had a decreased content after irradiation, most ultraviolet stabilizers did not change. During the migration tests with aqueous food simulants, additives were not released from either irradiated or unirradiated sheets. For the migration tests with n-heptane, however, all additives were released from the unirradiated sheet, while most of the antioxidants were not released or released only slightly. (author)

  19. Dynamic sterilization of titanium implants with ultraviolet light

    International Nuclear Information System (INIS)

    Singh, S.; Schaaf, N.G.

    1989-01-01

    All implantable devices must be sterile. However, autoclaves produce poor surface properties that jeopardize the integration process. The application of a modified ultraviolet light source has proven to enhance bioreactivity by controlling surface properties, but it lacks validation of its sterilization capabilities. Forty-eight titanium implants were contaminated with spores of the biological indicator Bacillus stearothermophilus and subjected to dynamic sterilization by ultraviolet light. Forty-seven of the implants were successfully sterilized, as indicated by not producing turbidity in a suitable growth medium. This sterilization technique only requires a 20-second exposure to achieve sterility

  20. Ultra-violet radiation: hazard in workplaces? (part II)

    International Nuclear Information System (INIS)

    Mohd Yusof Mohd Ali

    2003-01-01

    Not many workers are aware that apart from chemicals, physical agents, noise and machines which are known to be hazardous in workplaces, there exist another source of hazard which is equally important to be recognised and respected, that is hazard due to ultrviolet radiation (UV). This is the continuation of part I, which was discussed in the later issue. In this part, hazard of ultraviolet radiation were briefly discused i.e. effects on the skin and the eyes. Other subjects discussed are exposure limits, how to assess the radiation, protection against ultraviolet radiation

  1. An analysis of the repair processes in ultraviolet-irradiated Micrococcus luteus using purified ultraviolet-endonuclease

    International Nuclear Information System (INIS)

    Tomilin, N.V.; Zherebtsov, S.V.

    1982-01-01

    The measurement of the frequency of endonucleolytic incisions in ultraviolet-irradiated DNA serves as the test for the presence of pyrimidine dimers. In accordance with this approach, the lysates of three Micrococcus luteus strains containing radioactively labeled chromosomes were treated with purified M. luteus ultraviolet-endonuclease to trace segregation of dimers amongst parental and newly synthesized DNA and their removal during postreplication and excision DNA repair. A considerable proportion of the dimers in all strains tested proved to be insensitive to the action of exogenous incising enzyme. The use of chloramphenicol as an inhibitor of postirradiation protein synthesis in combination with ultraviolet-endonuclease treatment of DNA allowed to reveal at least two alternative pathways of postreplication repair: constitutively active recombinational pathway and inducible nonrecombinational one. (Auth.)

  2. Photoionization capable, extreme and vacuum ultraviolet emission in developing low temperature plasmas in air

    NARCIS (Netherlands)

    Stephens, J.; Fierro, A.; Beeson, S.; Laity, G.; Trienekens, D.; Joshi, R.P.; Dickens, J.; Neuber, A.

    2016-01-01

    Experimental observation of photoionization capable extreme ultraviolet and vacuum ultraviolet emission from nanosecond timescale, developing low temperature plasmas (i.e. streamer discharges) in atmospheric air is presented. Applying short high voltage pulses enabled the observation of the onset of

  3. Permeabilization of ultraviolet-irradiated chinese hamster cells with polyethylene glycol and introduction of ultraviolet endonuclease from Micrococcus luteus

    International Nuclear Information System (INIS)

    Yarosh, D.B.; Setlow, R.B.

    1981-01-01

    Chinese hamster V-79 cells were made permeable by treatment with polyethylene glycol and then incubated with a Micrococcus luteus extract containing ultraviolet-specific endonuclease activity. This treatment introduced nicks in irradiated, but not in unirradiated, deoxyribonucleic acid. The nicks remained open for at least 3 h; there was no loss of endonuclease-sensitive sites, and no excision of dimers as measured by chromatography was detected. In addition, there was no increase in ultraviolet resistance in treated cells. This suggests that the absence of a significant amount of excision repair in rodent cells is due to the lack of both incision and excision capacity

  4. Experience of Phototherapy in Dermatological Praxis in Complex Therapy of Psoriasis Patients

    Directory of Open Access Journals (Sweden)

    Hartmane Ilona

    2016-02-01

    Full Text Available Psoriasis is a chronic relapsing skin disease presenting with erythematous and papulous lesions with infiltration and extensive desquamation on the skin surface. It is a genetically determined, multifactorial dermatosis where genetic, immune, and environmental factors play significant roles in its development. In Latvia in treatment of different forms of extensively spreading psoriasis, PUVA (psoralen and ultraviolet A light therapy, a combined method, is administered, applying long-wave UVA radiation with wavelength 320–400 nm in combination with photosensibilisator 8-metoxypsoralen and medium wave length UVB radiation narrow-band phototherapy — 311 nm using specialised TL-01 lamps. The aim of our clinical investigation was to determine the efficacy of narrow-band phototherapy (UVB 311 nm in the complex treatment of patients with different severity of extensive psoriatic lesions treated in the Clinical Centre of Skin and Sexually Transmitted Diseases. Cases of clinical data of 260 patients with widely spread psoriasis were analysed. In the Group 1 (n = 102 receiving narrow-band UVB therapy, the mean and cumulative UVB dosage was 1.8 ± 0.6 and 21.5 ± 3.8 J/cm2, respectively, whereas in Group 2 (n = 91 it was 2.2 ± 0.1 and 27.7 ± 8.0 J/cm2. To obtain clinical recovery, 18 to 30 procedures were necessary (average 22 ± 4.1 with total irradiation dose received 110 ± 4.6 J/cm2. In 67 patients of the control group, PUVA therapy was administered, and positive therapeutic efficacy was observed in all patients. Clinical recovery was obtained in 86.2% in patients of the Group 1, in 82.4% — of Group 2, and in 80% — in 67 patients of the control group. Narrow-band (311 nm UVB phototherapy is currently one of the leading pathogenetical methods of treatment of patients with widespread psoriasis. It has high efficacy, good tolerability, does not have severe side effects and restrictions in use, in comparison with traditional PUVA therapy.

  5. Ultraviolet A phototherapy for sclerotic skin diseases: a systematic review.

    NARCIS (Netherlands)

    Kroft, Ilse; Berkhof, N.J.; Kerkhof, P.C.M. van de; Gerritsen, R.; Jong, E.M.G.J. de

    2008-01-01

    BACKGROUND: Ultraviolet (UV) A-1 phototherapy is now available for a variety of skin diseases. Increasingly since 1995, there have been investigations of the efficacy of UVA-1 (340-400 nm) therapy for sclerotic skin diseases. Most studies undertaken treated patients who had localized scleroderma,

  6. Ultraviolet extinction in M-supergiant circumstellar envelopes

    International Nuclear Information System (INIS)

    Buss, R.H. Jr.; Snow, T.P. Jr.

    1986-01-01

    Using International Ultraviolet (IUS) archival low-dispersion spectra, ultraviolet spectral extinctions were derived for the circumstellar envelopes of two M supergiants: HD 60414 and HD 213310. The observed stellar systems belong to a class of widely-separated spectroscopic binaries that are called VV Cephei stars. The total extinction was calculated by dividing the reddened fluxes with unreddened comparison fluxes of similar stars (g B2.5 for HD 213310 and a normalized s+B3 for HD 60414) from the reference atlas. After substracting the interstellar extinctions, which were estimated from the E(B-V) reddening of nearby stars, the resultant circumstellar extinctions were normalized at about 3.5 inverse microns. Not only is the 2175 A extinction bump absent in the circumstellar extinctions, but the far-ultraviolet extinction rise is also absent. The rather flat, ultraviolet extinction curves were interpreted as signatures of a population of noncarbonaceous, oxygen-rich grains with diameters larger than the longest observed wavelength

  7. The Physics and Diagnostic Potential of Ultraviolet Spectropolarimetry

    Science.gov (United States)

    Trujillo Bueno, Javier; Landi Degl'Innocenti, Egidio; Belluzzi, Luca

    2017-09-01

    The empirical investigation of the magnetic field in the outer solar atmosphere is a very important challenge in astrophysics. To this end, we need to identify, measure and interpret observable quantities sensitive to the magnetism of the upper chromosphere, transition region and corona. This paper provides an overview of the physics and diagnostic potential of spectropolarimetry in permitted spectral lines of the ultraviolet solar spectrum, such as the Mg ii h and k lines around 2800 Å, the hydrogen Lyman-α line at 1216 Å, and the Lyman-α line of He ii at 304 Å. The outer solar atmosphere is an optically pumped vapor and the linear polarization of such spectral lines is dominated by the atomic level polarization produced by the absorption and scattering of anisotropic radiation. Its modification by the action of the Hanle and Zeeman effects in the inhomogeneous and dynamic solar atmosphere needs to be carefully understood because it encodes the magnetic field information. The circular polarization induced by the Zeeman effect in some ultraviolet lines (e.g., Mg ii h & k) is also of diagnostic interest, especially for probing the outer solar atmosphere in plages and more active regions. The few (pioneering) observational attempts carried out so far to measure the ultraviolet spectral line polarization produced by optically pumped atoms in the upper chromosphere, transition region and corona are also discussed. We emphasize that ultraviolet spectropolarimetry is a key gateway to the outer atmosphere of the Sun and of other stars.

  8. Sensitivity of the vibrios to ultraviolet-radiation

    International Nuclear Information System (INIS)

    Banerjee, S.K.; Chatterjee, S.N.

    1977-01-01

    The ultraviolet-inactivation kinetics of a number of strains of Vibrio cholerae (classical), Vibrio cholerae (el tor), NAG vibrios and Vibrio parahaemolyticus were investigated. Statistical analyses revealed significant differences between any two of the four types of vibrio in respect of their sensitivity to U.V. (author)

  9. Vacuum ultraviolet photoabsorption spectroscopy of crystalline and amorphous benzene

    DEFF Research Database (Denmark)

    Dawes, Anita; Pascual, Natalia; Hoffmann, Soren V.

    2017-01-01

    We present the first high resolution vacuum ultraviolet photoabsorption study of amorphous benzene with com parisons to annealed crystalline benzene and the gas phase. Vapour deposited benzene layers w ere grow n at 25 K and annealed to 90 K under conditions pertinent to interstellaricy dust grains...

  10. Photochemical reaction monitoring by ultra-violet spectrophotometry.

    Science.gov (United States)

    Roig, B; Touraud, E; Thomas, O

    2002-11-01

    Within the framework of the monitoring of the trichloroacetylchloride (TCAC) photosynthesis, ultra-violet (UV) spectrophotometry is proposed as a simple and rapid tool allowing, in real time, the control of the process efficiency. A good correlation has been obtained between the results acquired by this alternative method and the standard gas chromatography.

  11. Ultraviolet and environmental stresses involved in the induction and ...

    African Journals Online (AJOL)

    Light is one of the most important environmental factors regulating plant development and genes expression. Ultraviolet takes up 7% of sunlight and it stimulates distinct responses in plant. Both UV-A and low influence of UV-B can induce the accumulation of anthocyanin via induction of the expression of anthocyanin ...

  12. Red tattoos, ultraviolet radiation and skin cancer in mice

    DEFF Research Database (Denmark)

    Lerche, Catharina M.; Heerfordt, Ida M.; Serup, Jørgen

    2017-01-01

    Ultraviolet radiation (UVR) induces skin cancer. The combination of UVR and red tattoos may be associated with increased risk of skin cancer due to potential carcinogens in tattoo inks. This combination has not been studied previously. Immunocompetent C3.Cg/TifBomTac hairless mice (n=99) were...

  13. Calibration of windowless photodiode for extreme ultraviolet pulse energy measurement

    Czech Academy of Sciences Publication Activity Database

    Koláček, Karel; Schmidt, Jiří; Štraus, Jaroslav; Frolov, Oleksandr

    2015-01-01

    Roč. 54, č. 35 (2015), s. 10454-10459 ISSN 1559-128X R&D Projects: GA MŠk(CZ) LG13029 Institutional support: RVO:61389021 Keywords : Photodetectors * Soft-X-ray * Extreme ultraviolet * Detection * Filters * Metrology Subject RIV: BH - Optics , Masers, Lasers Impact factor: 1.598, year: 2015

  14. Preventing Ultraviolet Light-Induced Damage: The Benefits of Antioxidants

    Science.gov (United States)

    Yip, Cheng-Wai

    2007-01-01

    Extracts of fruit peels contain antioxidants that protect the bacterium "Escherichia coli" against damage induced by ultraviolet light. Antioxidants neutralise free radicals, thus preventing oxidative damage to cells and deoxyribonucleic acid. A high survival rate of UV-exposed cells was observed when grapefruit or grape peel extract was…

  15. Key issues of ultraviolet radiation of OH at high altitudes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuhuai; Wan, Tian; Jiang, Jianzheng; Fan, Jing [State Key Laboratory of High Temperature Gasdynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-12-09

    Ultraviolet (UV) emissions radiated by hydroxyl (OH) is one of the fundamental elements in the prediction of radiation signature of high-altitude and high-speed vehicle. In this work, the OH A{sup 2}Σ{sup +}→X{sup 2}Π ultraviolet emission band behind the bow shock is computed under the experimental condition of the second bow-shock ultraviolet flight (BSUV-2). Four related key issues are discussed, namely, the source of hydrogen element in the high-altitude atmosphere, the formation mechanism of OH species, efficient computational algorithm of trace species in rarefied flows, and accurate calculation of OH emission spectra. Firstly, by analyzing the typical atmospheric model, the vertical distributions of the number densities of different species containing hydrogen element are given. According to the different dominating species containing hydrogen element, the atmosphere is divided into three zones, and the formation mechanism of OH species is analyzed in the different zones. The direct simulation Monte Carlo (DSMC) method and the Navier-Stokes equations are employed to compute the number densities of the different OH electronically and vibrationally excited states. Different to the previous work, the trace species separation (TSS) algorithm is applied twice in order to accurately calculate the densities of OH species and its excited states. Using a non-equilibrium radiation model, the OH ultraviolet emission spectra and intensity at different altitudes are computed, and good agreement is obtained with the flight measured data.

  16. Ultraviolet divergences in 1/N expansions of quantum field theories

    International Nuclear Information System (INIS)

    Rim, C.

    1984-01-01

    For asymptotically free theories, ultraviolet divergencies computed in 1/N expansion with dimensional regularization reduces to simple poles plus powers of Inelement of or finite terms. All divergences are determined by the two loop perturbative renormalization group functions. In an infrared free theory, however, element of = 0 becomes an essential singularity in the 1/N expansion

  17. Photoprotective Effect of Tea and its Extracts against Ultraviolet ...

    African Journals Online (AJOL)

    Ultraviolet (UV) exposure induces photodamage of skin. It is a matter of concern that the level of UV radiation reaching the earth surface is increasing as a result of depletion of the stratospheric ozone, and climate change. It is urgently necessary to develop strategies to protect the skin from UV-induced injuries. Tea extracts ...

  18. Graphene defect formation by extreme ultraviolet generated photoelectrons

    NARCIS (Netherlands)

    Gao, An; Lee, Christopher James; Bijkerk, Frederik

    2014-01-01

    We have studied the effect of photoelectrons on defect formation in graphene during extreme ultraviolet (EUV) irradiation. Assuming the major role of these low energy electrons, we have mimicked the process by using low energy primary electrons. Graphene is irradiated by an electron beam with energy

  19. LOW PRESSURE ULTRAVIOLET STUDIES FOR INACTIVIATION OF GIARDIA MURIS CYSTS

    Science.gov (United States)

    This research was initiated to confirm and expand the current database for the inactiviation of Giardia spp. using ultraviolet (UV) radiation. The path taken was to confirm earlier UV research that used excystation as the indication of viability. In this study, an in vitro excyst...

  20. LOW PRESSURE ULTRAVIOLET STUDIES FOR INACTIVATION OF GIARDIA MURIS CYSTS

    Science.gov (United States)

    This research was initiated to confirm and expand the current database for the inactivation of Giardia spp. using ultraviolet (UV) radiation. Initially, previous research that used in vitro excystation as the indicator for UV effectiveness was confirmed. Later, the in vitro excys...

  1. Strong overtones and combination bands in ultraviolet resonance Raman spectroscopy

    NARCIS (Netherlands)

    Efremov, E.V.; Ariese, F.; Mank, A.J.G.; Gooijer, C.

    2006-01-01

    Ultraviolet resonance Raman spectroscopy is carried out using a continuous wave frequency-doubled argon ion laser operated at 229, 244, and 257 nm in order to characterize the overtones and combination bands for several classes of organic compounds in liquid solutions. Contrary to what is generally

  2. Elastic modulus of Extreme Ultraviolet exposed single-layer graphene

    NARCIS (Netherlands)

    Mund, Baibhav Kumar; Gao, An; Sturm, Jacobus Marinus; Lee, Christopher James; Bijkerk, Frederik

    2015-01-01

    Highly transparent membranes are required for a number of applications, such as protective coatings for components in Extreme Ultraviolet (EUV) lithography, beam splitters (EUV pump-probe experiments), transmission gratings, and reticles. Graphene is an excellent candidate due to its high tensile

  3. Highly efficient deep ultraviolet generation by sum-frequency mixing ...

    Indian Academy of Sciences (India)

    Ultraviolet laser radiation; walk-off compensation; third harmonic generation; nonlinear optical material. ... Because of its large birefringence, BBO crystal permits the generation of UV radiation near 200 nm by THG ... A, B and C are three different configurations for THG, A – Single crystal, B – two crystals (B2 and B3 in.

  4. Effect of ultraviolet-B radiation on biochemical and antioxidant ...

    African Journals Online (AJOL)

    user

    The stratospheric ozone depletion and enhanced solar ultraviolet-B (UV-B) ... mechanism produced by enzymatic antioxidant such as catalase, peroxidase, ... absorb UV-B and prevent it from penetrating into the leaf mosophyll cells. The aim of this work was to investigate the effects of UV-B radiation on Indigofera tinctoria ...

  5. an assessment of ultraviolet radiation components of light emitted ...

    African Journals Online (AJOL)

    Dr

    therefore high for exposure limits of 8 hours for UV-B and UV-C and the 16 minutes for UV-A. The investigation ... has become particularly interesting as the ozone layer ... THEORY. Ultraviolet (UV) light is an electromagnetic radiation with a ...

  6. High power AlGaN ultraviolet light emitters

    International Nuclear Information System (INIS)

    Shatalov, Max; Sun, Wenhong; Jain, Rakesh; Lunev, Alex; Hu, Xuhong; Dobrinsky, Alex; Bilenko, Yuri; Yang, Jinwei; Gaska, Remis; Garrett, Gregory A; Rodak, Lee E; Wraback, Michael; Shur, Michael

    2014-01-01

    We present the analysis of the external quantum efficiency in AlGaN deep ultraviolet (DUV) light-emitting diodes (LEDs) on sapphire substrates and discuss factors affecting the output power of DUV LEDs. Performance of the LED is related to optimization of the device structure design and improvements of the epitaxial material quality. (invited article)

  7. High power AlGaN ultraviolet light emitters

    Science.gov (United States)

    Shatalov, Max; Sun, Wenhong; Jain, Rakesh; Lunev, Alex; Hu, Xuhong; Dobrinsky, Alex; Bilenko, Yuri; Yang, Jinwei; Garrett, Gregory A.; Rodak, Lee E.; Wraback, Michael; Shur, Michael; Gaska, Remis

    2014-06-01

    We present the analysis of the external quantum efficiency in AlGaN deep ultraviolet (DUV) light-emitting diodes (LEDs) on sapphire substrates and discuss factors affecting the output power of DUV LEDs. Performance of the LED is related to optimization of the device structure design and improvements of the epitaxial material quality.

  8. Protective role of Aspergillus fumigatus melanin against ultraviolet ...

    African Journals Online (AJOL)

    Melanin protects pigmented cells from physical and biological stresses which are associated with virulence in several important human pathogens, but little is known about the immune response to this ubiquitous biologic compound. Melanin content increased in Aspergillus fumigatus mycelium exposed to ultraviolet for 10 ...

  9. Invisible Misconceptions: Student Understanding of Ultraviolet and Infrared Radiation

    Science.gov (United States)

    Libarkin, Julie C.; Asghar, Anila; Crockett, C.; Sadler, Philip

    2011-01-01

    The importance of nonvisible wavelengths for the study of astronomy suggests that student understanding of nonvisible light is an important consideration in astronomy classrooms. Questionnaires, interviews, and panel discussions were used to investigate 6-12 student and teacher conceptions of ultraviolet (UV) and infrared (IR). Alternative…

  10. Infrared diffractive filtering for extreme ultraviolet multilayer Bragg reflectors

    NARCIS (Netherlands)

    Medvedev, Viacheslav; van den Boogaard, Toine; van der Meer, R.; Yakshin, Andrey; Louis, Eric; Krivtsun, V.M.; Bijkerk, Frederik

    2013-01-01

    Abstract: We report on the development of a hybrid mirror realized by integrating an EUV-reflecting multilayer coating with a lamellar grating substrate. This hybrid irror acts as an efficient Bragg reflector for extreme ultraviolet (EUV) radiation at a given wavelength while simultaneously

  11. Adverse effects of ultraviolet irradiation in atopic dermatitis.

    NARCIS (Netherlands)

    ten Berge, O.

    2010-01-01

    The overall aim of this thesis was to evaluate adverse effects of ultraviolet irradiation (UV) in atopic dermatitis (AD). We focused on the two important adverse effects of UV: photosensitivity and skin cancer risk associated with calcineurin inhibitor treatment. In chapter 2 and 3 we found that

  12. Epigallocatechin-3-gallate on Melanogenesis in Ultraviolet A ...

    African Journals Online (AJOL)

    compared to blank (control) which was neither treated by UVA nor by EGCG. TEM showed that UVA induced the formation of ... Biological Engineering Technology Co., Ltd,. (Shanghai, China). PA102 Bradford protein assay kit ..... Sliney DH. Estimating the solar ultraviolet radiation exposure to an intraocular eye implant.

  13. 21 CFR 179.39 - Ultraviolet radiation for the processing and treatment of food.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ultraviolet radiation for the processing and..., PROCESSING AND HANDLING OF FOOD Radiation and Radiation Sources § 179.39 Ultraviolet radiation for the processing and treatment of food. Ultraviolet radiation for the processing and treatment of food may be...

  14. 21 CFR 1040.20 - Sunlamp products and ultraviolet lamps intended for use in sunlamp products.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Sunlamp products and ultraviolet lamps intended... intended to be exposed to ultraviolet radiation from the product, as recommended by the manufacturer. (2... irradiation of any part of the living human body, by ultraviolet radiation with wavelengths in air between 200...

  15. Superhydrophobic Polyimide via Ultraviolet Photooxidation: The Evolution of Surface Morphology and Hydrophobicity under Different Ultraviolet Intensities

    Directory of Open Access Journals (Sweden)

    Hongyu Gu

    2015-01-01

    Full Text Available Ultraviolet (UV photooxidation has recently been developed to fabricate superhydrophobic polyimide (PI films in combination with fluoroalkylsilane modification. However, it remains unclear whether the surface morphology and hydrophobicity are sensitive to technical parameters such as UV intensity and radiation environment. Herein, we focus on the effects of UV intensity on PI surface structure and wettability to gain comprehensive understanding and more effective control of this technology. Scanning electron microscopy (SEM and atomic force microscopy (AFM results showed that UV intensity governed the evolutionary pattern of surface morphology: lower UV intensity (5 mW/cm2 facilitated in-plane expansion of dendritic protrusions while stronger UV (10 and 15 mW/cm2 encouraged localized growth of protrusions in a piling-up manner. Surface roughness and hydrophobicity maximized at the intensity of 10 mW/cm2, as a consequence of the slowed horizontal expansion and preferred vertical growth of the protrusions when UV intensity increased. Based on these results, the mechanism that surface micro/nanostructures developed in distinct ways when exposed to different UV intensities was proposed. Though superhydrophobicity (water contact angle larger than 150° can be achieved at UV intensity not less than 10 mW/cm2, higher intensity decreased the effectiveness. Therefore, the UV photooxidation under 10 mW/cm2 for 72 h is recommended to fabricate superhydrophobic PI films.

  16. Ultraviolet and short wavelength visible light exposure: why ultraviolet protection alone is not adequate.

    Science.gov (United States)

    Reichow, Alan W; Citek, Karl; Edlich, Richard F

    2006-01-01

    The danger of exposure to ultraviolet (UV) radiation in both the natural environment and artificial occupational settings has long been recognized by national and international standards committees and worker safety agencies. There is an increasing body of literature that suggests that protection from UV exposure is not enough. Unprotected exposure to the short wavelengths of the visible spectrum, termed the "blue light hazard", is gaining acceptance as a true risk to long-term visual health. Global standards and experts in the field are now warning that those individuals who spend considerable time outdoors should seek sun filter eyewear with high impact resistant lenses that provide 100% UV filtration, high levels of blue light filtration, and full visual field lens/frame coverage as provided by high wrap eyewear. The Skin Cancer Foundation has endorsed certain sunglasses as "product[s]...effective [as] UV filter[s] for the eyes and surrounding skin". However, such endorsement does not necessarily mean that the eyewear meets all the protective needs for outdoor use. There are several brands that offer products with such protective characteristics. Performance sun eyewear by Nike Vision, available in both corrective and plano (nonprescription) forms, is one such brand incorporating these protective features.

  17. Survey of the variation in ultraviolet outputs from ultraviolet A sunbeds in Bradford.

    Science.gov (United States)

    Wright, A L; Hart, G C; Kernohan, E; Twentyman, G

    1996-02-01

    Concerns have been expressed for some time regarding the growth of the cosmetic suntanning industry and the potential harmful effects resulting from these exposures. Recently published work has appeared to confirm a link between sunbed use and skin cancer. A previous survey in Oxford some years ago demonstrated significant output variations, and we have attempted to extend and update that work. Ultraviolet A, UVB and blue-light output measurements were made on 50 sunbeds using a radiometer fitted with broad-band filters and detectors. A number of irradiance measurements were made on each sunbed within each waveband so that the uniformity of the output could also be assessed. UVA outputs varied by a factor of 3, with a mean of 13.5 mW/cm2; UVB outputs varied by a factor of 60, with a mean of 19.2 microW/cm2; and blue-light outputs varied by a factor of 2.5, with a mean of 2.5 mW/cm2. Outputs fall on average to 80% of the central value at either end of the sunbed. Facial units in sunbeds ranged in output between 18 and 45 mW/cm2. Output uniformity shows wide variation, with 16% of the sunbeds having an axial coefficient of variation > 10%. UVB output is highly tube-specific. Eyewear used in sunbeds should also protect against blue light.

  18. Zinc Selenide-Based Schottky Barrier Detectors for Ultraviolet-A and Ultraviolet-B Detection

    Directory of Open Access Journals (Sweden)

    V. Naval

    2010-01-01

    Full Text Available Wide-bandgap semiconductors such as zinc selenide (ZnSe have become popular for ultraviolet (UV photodetectors due to their broad UV spectral response. Schottky barrier detectors made of ZnSe in particular have been shown to have both low dark current and high responsivity. This paper presents the results of electrical and optical characterization of UV sensors based on ZnSe/Ni Schottky diodes fabricated using single-crystal ZnSe substrate with integrated UV-A (320–400 nm and UV-B (280–320 nm filters. For comparison, characteristics characterization of an unfiltered detector is also included. The measured photoresponse showed good discrimination between the two spectral bands. The measured responsivities of the UV-A and UV-B detectors were 50 mA/W and 10 mA/W, respectively. A detector without a UV filter showed a maximum responsivity of about 110 mA/W at 375 nm wavelength. The speed of the unfiltered detector was found to be about 300 kHz primarily limited by the RC time constant determined largely by the detector area.

  19. Establishing a ultraviolet radiation observational network and enhancing the study on ultraviolet radiation

    Science.gov (United States)

    Bai, Jianhui; Wang, Gengchen

    2003-09-01

    On the basis of analyzing observational data on solar radiation, meteorological parameters, and total ozone amount for the period of January 1990 to December 1991 in the Beijing area, an empirical calculation method for ultraviolet radiation (UV) in clear sky is obtained. The results show that the calculated values agree well with the observed, with maximum relative bias of 6.2% and mean relative bias for 24 months of 1.9%. Good results are also obtained when this method is applied in Guangzhou and Mohe districts. The long-term variation of UV radiation in clear sky over the Beijing area from 1979 to 1998 is calculated, and the UV variation trends and causes are discussed: direct and indirect UV energy absorption by increasing pollutants in the troposphere may have caused the UV decrease in clear sky in the last 20 years. With the enhancement of people’s quality of life and awareness of health, it will be valuable and practical to provid UV forecasts for typical cities and rural areas. So, we should develop and enhance UV study in systematic monitoring, forecasting, and developing a good and feasible method for UV radiation reporting in China, especially for big cities.

  20. Exposure of Finnish population to ultraviolet radiation and radiation measurements

    International Nuclear Information System (INIS)

    Hoikkala, M.; Lappalainen, J.; Leszczynski, K.; Paile, W.

    1990-01-01

    This report is based on a survey of the literature on radiation risks involved in sunbathing and the use of solaria. The purpose of the report is to provide background information for the development of regulations on solaria and for informing the public about the risks posed by solaria and the sun. The report gives an overview of the properties and biological effects of ultraviolet radiation. The most important regulations and recommendations issued in various countries are presented. The connection between ultraviolet radiation and the risks of skin cancer is examined both on a general level and in reference to information obtained from the Finnish Cancer Registry. In Finland, the incidence of melanomas nearly tripled between 1960 and 1980. The most important cause is considered to be the population's increased exposure to the su's ultraviolet radiation. There are no reliable data on the connection between the use of solaria and the risks of skin cancer. It is estimated, however, that solaria account for less than 10 per cent of the skin cancer risk of the whole population. There are some difficult physical problems associated with the measurement of ultraviolet radiation emitted by both natural sources and solaria. A preliminary study of these problems has been undertaken by means of a survey of the available literature, supplemented by a review of measurements performed by the Finnish Centre For Radiation and Nuclear Safety. The estimated inaccuracy of the Optronic 742 spectroradiometer used by the Centre in the measurement of ultraviolet radiation emitted by the sun and solaria is about +-14%

  1. Do birds in flight respond to (ultra)violet lighting?

    Institute of Scientific and Technical Information of China (English)

    Roel May; Jens Åström; Øyvind Hamre; Espen Lie Dahl

    2017-01-01

    Background: Concerns for bird collisions with wind turbines affect the deployment of onshore and offshore wind-power plants. To avoid delays in consenting processes and to streamline the construction and operation phase, func-tional mitigation measures are required which efficiently reduces bird mortality. Vision is the primary sensory system in birds, which for a number of species also includes the ultraviolet spectrum. Many bird species that are known to collide with offshore wind turbines are sensitive in the violet or ultraviolet spectrum. For species that are mainly active at lower ambient light levels, lighting may deter birds from the lit area. Utilizing (ultra)violet lights may in addition not disturb humans. However, we do not know whether UV-sensitive birds in flight actually respond behaviourally to UV lights. Methods: We therefore tested the efficacy of two types of lights within the violet (400 nm) and ultraviolet (365 nm) spectrum to deter birds from the lit area. These lights were placed vertically and monitored continuously between dusk and dawn using an avian radar system. Results: Relative to control nights, bird flight activity (abundance) was 27% lower when the ultraviolet light was on. Violet light resulted in a 12% decrease in overall abundance, and in addition, a vertical displacement was seen, increasing the average flight altitude by 7 m. Although temporal changes occurred, this effect persisted over the season below 40 m above sea level. Conclusions: Although the results from this pilot study are promising, we argue there still is a long way to go before a potentially functional design to mitigate collisions that has proven to be effective in situ may be in place.

  2. Ultraviolet photometry from the orbiting astronomical observatory. XX. The ultraviolet extinction bump

    International Nuclear Information System (INIS)

    Savage, B.D.

    1975-01-01

    Interstellar extinction curves over the wavelength region 1800--3600 A are presented for 36 stars. The stars have E (B-V) in the range 0.03 to 0.55, and are mostly confined to the brighter OB associations distributed along the plane of the Galaxy. Every extinction curve exhibits a broad extinction bump peaking near 2175 A (4.6 μ -1 ). The position of the peak and the profile of the feature appear remarkably constant among the sample of stars. With only a few exceptions, E (lambda)-3320, a measure of the strength of the feature, correlates very well with E (B-V), implying that the bump has an interstellar rather than a circumstellar origin. The observation that the bump position and shape are constant, or very nearly constant, places severe restrictions on the grain geometrical parameters if the feature is to be explained by classical scattering theory employing bulk optical constants. In fact, the restrictions are so severe that an alternate explanation seems to be required unless the dust grains that exist in widely separated regions of space and under very different physical conditions have nearly identical size and shape distributions. Three extinction curves that extend to 1100 A are also presented. These curves show the same general extinction characteristics reported earlier. The curve for 22 Sco provides another example of a star that is []physically associated with nebulosity and that also has abnormally low far-ultraviolet extinction. We have searched the extinction curves for fine structure such as abrupt slope changes or new diffuse interstellar features. Unfortunately, there is no convincing evidence for such structure over the interval 1800--3600 A. (auth)

  3. Optimization of curved drift tubes for ultraviolet-ion mobility spectrometry

    Science.gov (United States)

    Ni, Kai; Ou, Guangli; Zhang, Xiaoguo; Yu, Zhou; Yu, Quan; Qian, Xiang; Wang, Xiaohao

    2015-08-01

    Ion mobility spectrometry (IMS) is a key trace detection technique for toxic pollutants and explosives in the atmosphere. Ultraviolet radiation photoionization source is widely used as an ionization source for IMS due to its advantages of high selectivity and non-radioactivity. However, UV-IMS bring problems that UV rays will be launched into the drift tube which will cause secondary ionization and lead to the photoelectric effect of the Faraday disk. So air is often used as working gas to reduce the effective distance of UV rays, but it will limit the application areas of UV-IMS. In this paper, we propose a new structure of curved drift tube, which can avoid abnormally incident UV rays. Furthermore, using curved drift tube may increase the length of drift tube and then improve the resolution of UV-IMS according to previous research. We studied the homogeneity of electric field in the curved drift tube, which determined the performance of UV-IMS. Numerical simulation of electric field in curved drift tube was conducted by SIMION in our study. In addition, modeling method and homogeneity standard for electric field were also presented. The influences of key parameters include radius of gyration, gap between electrode as well as inner diameter of curved drift tube, on the homogeneity of electric field were researched and some useful laws were summarized. Finally, an optimized curved drift tube is designed to achieve homogenous drift electric field. There is more than 98.75% of the region inside the curved drift tube where the fluctuation of the electric field strength along the radial direction is less than 0.2% of that along the axial direction.

  4. Effects of exposure to ultraviolet light on the development of Rana pipiens, the northern leopard frog

    International Nuclear Information System (INIS)

    Williams, J.J.; Wofford, H.W.

    1996-01-01

    The increase in ultraviolet light intensity levels due to ozone depletion recently has been linked to the decline in amphibian population. In this experiment, eggs and larvae of Rana pipiens were subjected to differing amounts of ultraviolet radiation to determine the effects of ultraviolet light on the development of amphibian tadpoles. The total length, length of body without tail, and maximum width of each specimen was recorded for a month of the tadpoles' development, including several measurements after the ultraviolet exposures were concluded. It was found that ultraviolet exposure significantly reduced the size of the organisms in comparison with the control group in all three measured areas. Ultraviolet radiation altered the health and appearance of the exposed organisms and was lethal at large amounts. This experiment showed that ultraviolet radiation could cause many problems in developing amphibians. By slowing their development and physically weakening predation, thus contributing to a decline in overall population levels

  5. Tanning lamps ultraviolet emissions and compliance with technical standards

    International Nuclear Information System (INIS)

    Bonino, A.; Facta, S.; Saudino, S.; Anglesio, L.; D'Amore, G.

    2009-01-01

    In this work the compliance of tanning lamps with technical standards EN 60335-2-27 'Household and similar electrical appliances-Safety. Part 2: Particular requirements for appliances for skin exposure to ultraviolet and infrared radiation' was analysed. Results of this analysis showed that none of the examined technical documentation produced by the lamps manufacturers is fully compliant with the standard technique. Furthermore data reported in the same manuals, such as effective radiant exposure or irradiance, would indicate that these sources may be the cause of undue exposure to ultraviolet (UV) radiation. For this reason a measurement campaign on UV lamps used in tanning salons was organised. The first results of these measurements seem to confirm the doubts raised from the analysis of the lamp manuals: the use of a tanning lamp can lead to UV radiation exposure levels higher than reference maximum values recommended by EN 60335-2-27. (authors)

  6. The ultraviolet extinction properties of the 30 Dor Nebula

    Science.gov (United States)

    De Marchi, Guido; Panagia, Nino

    2018-01-01

    Recent investigation of the extinction law in 30 Dor and the Tarantula Nebula, at optical and near infrared wavelengths, has revealed a ratio of total to selective extinction RV=AV/E(B-V) of about 4.5. This indicates a larger proportion of large grains than in the Galactic diffuse interstellar medium. Possible origins include coalescence of small grains, grain growth, selective destruction of small grains, and fresh injection of large grains. From a study of the ultraviolet extinction properties of three Wolf-Rayet stars in 30 Dor (R 139, R 140, R 145), observed with the International Ultraviolet Explorer, we show that the excess of large grains does not come at the expense of small grains, which are still present. Fresh injection of large grains by supernova explosions appears to be the dominant mechanism.

  7. Ultraviolet divergences in non-renormalizable supersymmetric theories

    International Nuclear Information System (INIS)

    Smilga, A.

    2017-01-01

    We present a pedagogical review of our current understanding of the ultraviolet structure of N =(1, 1) 6D supersymmetric Yang-Mills theory and of N = 8 4D supergravity. These theories are not renormalizable, they involve power ultraviolet divergences and, in all probability, an infinite set of higher-dimensional counterterms that contribute to on-mass-shell scattering amplitudes. A specific feature of supersymmetric theories (especially of extended supersymmetric theories) is that these counterterms may not be invariant off-shell under the full set of supersymmetry transformations. The lowest-dimensional nontrivial counterterm is supersymmetric on-shell. Still higher counterterms may lose even the on-shell invariance. On the other hand, the full effective Lagrangian, generating the amplitudes and representing an infinite sum of counterterms, still enjoys the complete symmetry of original theory. We also discuss simple supersymmetric quantum-mechanical models that exhibit the same behavior.

  8. Ultraviolet and infrared aspects of the axial anomaly. I

    International Nuclear Information System (INIS)

    Horejsi, J.

    1992-01-01

    The paper is the first part of a brief review of some perturbative aspects of the Adler-Bell-Jackiw axial anomaly, described in terms of ultraviolet and infrared behavior of the famous VVA triangle graph. Apart from a general overview of the diversified role played by the anomaly in quantum field theory and particle physics, an elementary introduction is presented to the subject of the anomaly, comprehensible to an uninitiated reader with only a basic background in quantum field theory. The ultraviolet aspects of the anomaly are stressed and the topics covered are the following: vector and axial-vector Ward identities for the VVA triangle graph; the anomaly and several ways to derive it, namely the symmetric momentum cut-off and shifting the integration variables in linearly divergent integrals; the Adler-Rosenberg argument; the Pauli-Villars method; and dimensional regularization. (author) 2 figs., 34 refs

  9. Increased exposure of Southern Ocean phytoplankton to ultraviolet radiation

    Science.gov (United States)

    Lubin, Dan; Arrigo, Kevin R.; van Dijken, Gert L.

    2004-05-01

    Satellite remote sensing of both surface solar ultraviolet radiation (UVR) and chlorophyll over two decades shows that biologically significant ultraviolet radiation increases began to occur over the Southern Ocean three years before the ozone ``hole'' was discovered. Beginning in October 1983, the most frequent occurrences of enhanced UVR over phytoplankton-rich waters occurred in the Weddell Sea and Indian Ocean sectors of the Southern Ocean, impacting 60% of the surface biomass by the late 1990s. These results suggest two reasons why more serious impacts to the base of the marine food web may not have been detected by field experiments: (1) the onset of UVR increases several years before dedicated field work began may have impacted the most sensitive organisms long before such damage could be detected, and (2) most biological field work has so far not taken place in Antarctic waters most extensively subjected to enhanced UVR.

  10. Nonlinear wave-mixing processes in the extreme ultraviolet

    International Nuclear Information System (INIS)

    Misoguti, L.; Christov, I. P.; Backus, S.; Murnane, M. M.; Kapteyn, H. C.

    2005-01-01

    We present data from two-color high-order harmonic generation in a hollow waveguide, that suggest the presence of a nonlinear-optical frequency conversion process driven by extreme ultraviolet light. By combining the fundamental and second harmonic of an 800 nm laser in a hollow-core fiber, with varying relative polarizations, and by observing the pressure and power scaling of the various harmonic orders, we show that the data are consistent with a picture where we drive the process of high-harmonic generation, which in turn drives four-wave frequency mixing processes in the extreme EUV. This work promises a method for extending nonlinear optics into the extreme ultraviolet region of the spectrum using an approach that has not previously been considered, and has compelling implications for generating tunable light at short wavelengths

  11. Ultraviolet spectrographs for thermospheric and ionospheric remote sensing

    International Nuclear Information System (INIS)

    Dymond, K.F.; McCoy, R.P.

    1993-01-01

    The Naval Research Laboratory (NRL) has been developing far- and extreme-ultraviolet spectrographs for remote sensing the Earth's upper atmosphere and ionosphere. The first of these sensors, called the Special Sensor Ultraviolet Limb Imager (SSULI), will be flying on the Air Force's Defense Meteorological Satellite Program (DMSP) block 5D3 satellites as an operational sensor in the 1997-2010 time frame. A second sensor, called the High-resolution ionospheric and Thermospheric Spectrograph (HITS), will fly in late 1995 on the Air Force Space Test Program's Advanced Research and Global Observation Satellite (ARGOS, also known as P91-1) as part of NRL's High Resolution Airglow and Auroral Spectroscopy (HIRAAS) experiment. Both of these instruments are compact and do not draw much power and would be good candidates for small satellite applications. The instruments and their capabilities are discussed. Possible uses of these instruments in small satellite applications are also presented

  12. The ultraviolet interstellar extinction curve in the Pleiades

    Science.gov (United States)

    Witt, A. N.; Bohlin, R. C.; Stecher, T. P.

    1981-01-01

    The wavelength dependence of ultraviolet extinction in the Pleiades dust clouds has been determined from IUE observations of HD 23512, the brightest heavily reddened member of the Pleiades cluster. There is evidence for an anomalously weak absorption bump at 2200 A, followed by an extinction rise in the far ultraviolet with an essentially normal slope. A relatively weak absorption band at 2200 A and a weak diffuse absorption band at 4430 A seem to be common characteristics of dust present in dense clouds. Evidence is presented which suggests that the extinction characteristics found for HD 23512 are typical for a class of extinction curves observed in several cases in the Galaxy and in the LMC.

  13. Action spectra in mammalian cells exposed to ultraviolet radiation

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    A review is given of the literature published since 1977 on action spectra in mammalian cells exposed to ultraviolet radiation in the wavelength region above 220 nm. Action spectra for lethal events are discussed for cell inactivation in normal cells, growth arrested cells and photosensitive cells. Action spectra for non-lethal events are also discussed in relation to pyrimidine dimer formation, photoreactivation and the use of photosensitisers. It was concluded from these studies that damage to the DNA, and the extent of the repair of this damage, seems to determine a cell's response to such parameters as inactivation, mutation, transformation, latent viral activation, cellular viral capacity and ultraviolet enhanced viral reactivation. In addition to the direct effects of UV on DNA, photosensitization of cellular responses with chemicals such as 8-MOP extend the wavelength range at which damage can be demonstrated. (U.K.)

  14. Ultraviolet irradiation disrupts somatic pili structure and function

    Energy Technology Data Exchange (ETDEWEB)

    Silverblatt, F.J.

    1979-09-01

    Three piliated bacterial species were exposed to ultraviolet light and the effect of increasing duration of irradiation on the integrity of the somatic pili was quantitated by negative-stain electron microscopy. Heavily piliated Proteus mirabilis became devoid of pili after 20 min of irradiation, but Escherichia coli and Neisseria gonorrhoeae required 40 min for complete depiliation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that new, small molecular weight fragments appeared after irradiation of purified E. coli pili, suggesting that cleavage of the peptide chain rather than dissociation of pilin monomers accounted for the loss of pili structure. These observations indicate that the ultrastructural integrity and function of pili can be disrupted by ultraviolet light.

  15. Ultraviolet laser deposition of graphene thin films without catalytic layers

    KAUST Repository

    Sarath Kumar, S. R.

    2013-01-09

    In this letter, the formation of nanostructured graphene by ultraviolet laser ablation of a highly ordered pyrolytic graphite target under optimized conditions is demonstrated, without a catalytic layer, and a model for the growth process is proposed. Previously, graphene film deposition by low-energy laser (2.3 eV) was explained by photo-thermal models, which implied that graphene films cannot be deposited by laser energies higher than the C-C bond energy in highly ordered pyrolytic graphite (3.7 eV). Here, we show that nanostructured graphene films can in fact be deposited using ultraviolet laser (5 eV) directly over different substrates, without a catalytic layer. The formation of graphene is explained by bond-breaking assisted by photoelectronic excitation leading to formation of carbon clusters at the target and annealing out of defects at the substrate.

  16. Occupational standard for exposure to ultraviolet radiation (1989)

    International Nuclear Information System (INIS)

    1989-12-01

    The exposure limit (EL) values in this standard refer to ultraviolet radiation (UVR) in the spectral region between 180 and 400 nm and represents conditions under which it is believed that nearly all workers may be repeatedly exposed without adverse effect. The EL values for exposure of the eye or the skin may be used to evaluate potentially hazardous exposure from UVR. The limits do not apply to ultraviolet lasers. The values should be used as guides in the control of exposure to both pulsed and continuous sources of UVR where the exposure duration is not less than 0.1 μsec. The ELs are below levels used for UV exposures of patients as a part of medical treatment or for elective cosmetic purposes. They are intended as upper limits for non therapeutic and non cosmetic exposure. 2 refs., 2 tabs

  17. Ultraviolet laser deposition of graphene thin films without catalytic layers

    KAUST Repository

    Sarath Kumar, S. R.; Alshareef, Husam N.

    2013-01-01

    In this letter, the formation of nanostructured graphene by ultraviolet laser ablation of a highly ordered pyrolytic graphite target under optimized conditions is demonstrated, without a catalytic layer, and a model for the growth process is proposed. Previously, graphene film deposition by low-energy laser (2.3 eV) was explained by photo-thermal models, which implied that graphene films cannot be deposited by laser energies higher than the C-C bond energy in highly ordered pyrolytic graphite (3.7 eV). Here, we show that nanostructured graphene films can in fact be deposited using ultraviolet laser (5 eV) directly over different substrates, without a catalytic layer. The formation of graphene is explained by bond-breaking assisted by photoelectronic excitation leading to formation of carbon clusters at the target and annealing out of defects at the substrate.

  18. Optical and ultraviolet observations of Nova Vul 1987

    Energy Technology Data Exchange (ETDEWEB)

    Starrfield, S.; Stryker, L.L.; Sonneborn, G.; Sparks, W.M.; Wagner, R.M.; Ferland, G.; Gallagher, J.S.; Wade, R.; Williams, R.E.; Gehrz, R.D.

    1988-01-01

    We present a brief summary of the outburst for a nova that was discovered in November 1987 and has been followed since that time. Although we were able to observe it with the IUE at maximum, its ultraviolet energy faded rapidly and after the first two weeks we were no longer able to observe it at IUE wavelengths. It was observed to form a thick dust shell and currently is in the nebular stage. 6 figs.

  19. Telescience - Concepts and contributions to the Extreme Ultraviolet Explorer mission

    Science.gov (United States)

    Marchant, Will; Dobson, Carl; Chakrabarti, Supriya; Malina, Roger F.

    1987-01-01

    It is shown how the contradictory goals of low-cost and fast data turnaround characterizing the Extreme Ultraviolet Explorer (EUVE) mission can be achieved via the early use of telescience style transparent tools and simulations. The use of transparent tools reduces the parallel development of capability while ensuring that valuable prelaunch experience is not lost in the operations phase. Efforts made to upgrade the 'EUVE electronics' simulator are described.

  20. The Copernicus ultraviolet spectral atlas of Iota Herculis

    Science.gov (United States)

    Upson, W. L., II; Rogerson, J. B., Jr.

    1980-01-01

    An ultraviolet spectral atlas is presented for the B3 IV star Iota Herculis, which has been scanned from 999 to 1467 A by the Princeton spectrometer aboard the Copernicus satellite. From 999 to 1422 A the observations have a nominal resolution of 0.05 A. At the longer wavelengths the resolution is 0.1 A. The atlas is presented in graphs. Lines identified in the spectrum are also listed.

  1. On hot and cool stars, spectroscopic investigations in the ultraviolet

    International Nuclear Information System (INIS)

    Hucht, K.A. van der.

    1978-01-01

    Measured ultraviolet stellar spectra are compared with theoretically synthesised spectra. Three A-type and some B-type stars have been observed. The expanding outer layers of cool giants and supergiants are dealt with. K-type and M-type stars are discussed. The problem of the continuous energy distribution of Wolf-Tayet stars derived from observations is considered. (C.F.)

  2. Ultraviolet radiation response of two heterotropy Antarctic marine bacterial

    International Nuclear Information System (INIS)

    Hernandez, Edgardo A.; Ferreyra, Gustavo A.; Mac Cormack, Walter P.

    2004-01-01

    Two Antarctic marine bacterial strains, were exposed to different irradiance of ultraviolet (UV) solar radiation using several experimental protocols and interferential filters. Results showed that both, UV-A and UV-B radiation produce deleterious effects on two tested bacterial strains. The mortality values under UVB treatments were higher than those observed under UVA treatments. UVvi strain proved to be more resistant to UV radiation than the UVps strain. (author) [es

  3. MgII Observations Using the MSFC Solar Ultraviolet Magnetograph

    Science.gov (United States)

    West, Edward; Cirtain, Jonathan; Kobayashi, Ken; Davis, John; Gary, Allen; Adams, Mitzi

    2011-01-01

    This paper will describe the scientific goals of our sounding rocket program, the Solar Ultraviolet Magnetograph Investigation (SUMI). This paper will present a brief description of the optics that were developed to meet SUMI's scientific goals, discuss the spectral, spatial and polarization characteristics of SUMI s optics, describe SUMI's flight which was launched 7/30/2010, and discuss what we have learned from that flight.

  4. Molecular alignment dependent electron interference in attosecond ultraviolet photoionization

    Directory of Open Access Journals (Sweden)

    Kai-Jun Yuan

    2015-01-01

    Full Text Available We present molecular photoionization processes by intense attosecond ultraviolet laser pulses from numerical solutions of time-dependent Schrödinger equations. Simulations preformed on a single electron diatomic H2+ show minima in molecular photoelectron energy spectra resulting from two center interference effects which depend strongly on molecular alignment. We attribute such sensitivity to the spatial orientation asymmetry of the photoionization process from the two nuclei. A similar influence on photoelectron kinetic energies is also presented.

  5. Molecular alignment dependent electron interference in attosecond ultraviolet photoionization

    Science.gov (United States)

    Yuan, Kai-Jun; Bandrauk, André D.

    2015-01-01

    We present molecular photoionization processes by intense attosecond ultraviolet laser pulses from numerical solutions of time-dependent Schrödinger equations. Simulations preformed on a single electron diatomic H2+ show minima in molecular photoelectron energy spectra resulting from two center interference effects which depend strongly on molecular alignment. We attribute such sensitivity to the spatial orientation asymmetry of the photoionization process from the two nuclei. A similar influence on photoelectron kinetic energies is also presented. PMID:26798785

  6. Effects of Ultraviolet Radiation on Human Health (invited paper)

    International Nuclear Information System (INIS)

    MacKie, R.M.

    2000-01-01

    The detrimental and beneficial effects of exposure to ultraviolet radiation in the UVB and UVA ranges are discussed. The main benefit of UV radiation is promoting the synthesis of vitamin D from precursors in the skin. Detrimental effects include acute sun damage in the form of sunburn and chronic sun damage leading to photoageing and possibly to cutaneous malignancies. Other detrimental effects of UV exposure include photosensitivity reactions to ingested drugs and rare examples of genetically determined photosensitivies. (author)

  7. Effects of Ultraviolet Radiation on Human Health (invited paper)

    Energy Technology Data Exchange (ETDEWEB)

    MacKie, R.M

    2000-07-01

    The detrimental and beneficial effects of exposure to ultraviolet radiation in the UVB and UVA ranges are discussed. The main benefit of UV radiation is promoting the synthesis of vitamin D from precursors in the skin. Detrimental effects include acute sun damage in the form of sunburn and chronic sun damage leading to photoageing and possibly to cutaneous malignancies. Other detrimental effects of UV exposure include photosensitivity reactions to ingested drugs and rare examples of genetically determined photosensitivies. (author)

  8. Thermoluminescent phosphors for ultraviolet radiation dosimetry - a review

    International Nuclear Information System (INIS)

    Nagpal, J.S.

    2001-01-01

    Intrinsic TL response of CaSO 4 , CaF 2 , Al 2 O 3 (Si,Ti), Mg 2 SiO 4 : Tb and lamp phosphors to ultraviolet radiation is reviewed. Taking into consideration the characteristics such as afterglow at RT, rate/flux dependence, linearity of response, useful range, spectral dependence and effect of sequential/tandem UV exposures CaF 2 :Eu 2+ is an ideal TL dosemeter for UV radiation dosimetry. (author)

  9. Satellite Atmospheric Radiance Measurements in the Vacuum Ultraviolet.

    Science.gov (United States)

    1979-07-05

    APERTURE I I 1_ _~~J ;~- WHEEL MOTOR IDRIVE r~~ II I :_-~I ~~~~~~~~~~~~~~~~~~ ~~~_I ~~APERT URE WHEEL\\ ELLIPSOIDAL PRIMARY MIRROR VV ~ V SUNSHADE V I...Table 1. Vacuum Ultraviolet Backg rounds Sensors (Cont ) P~ iot ometer Interf erence Filters (A) 1216 1340 1550 1750 no f

  10. Surface processing: existing and potential applications of ultraviolet light.

    Science.gov (United States)

    Manzocco, Lara; Nicoli, Maria Cristina

    2015-01-01

    Solid foods represent optimal matrices for ultraviolet processing with effects well beyond nonthermal surface disinfection. UV radiation favors hormetic response in plant tissues and degradation of toxic compound on the product surface. Photoinduced reactions can also provide unexplored possibilities to steer structure and functionality of food biopolymers. The possibility to extensively exploit this technology will depend on availability of robust information about efficacious processing conditions and adequate strategies to completely and homogeneously process food surface.

  11. A search for thermal extreme ultraviolet radiation from nearby pulsars

    International Nuclear Information System (INIS)

    Greenstein, G.; Margon, B.

    1977-01-01

    We present the first extreme ultraviolet (100-1000 A) observations of radio pulsars. Using an EUV telescope carried aboard the Apollo-Soyuz mission, data were acquired on the nearby pulsars PSR 1133 + 16, 1451 - 68 and 1929 + 10. The data are interpreted to set limits on the effective temperatures of the neutron stars, yielding T 5 K in the best cases, and the limits compared with theoretical predictions. (orig./BJ) [de

  12. System performance modeling of extreme ultraviolet lithographic thermal issues

    International Nuclear Information System (INIS)

    Spence, P. A.; Gianoulakis, S. E.; Moen, C. D.; Kanouff, M. P.; Fisher, A.; Ray-Chaudhuri, A. K.

    1999-01-01

    Numerical simulation is used in the development of an extreme ultraviolet lithography Engineering Test Stand. Extensive modeling was applied to predict the impact of thermal loads on key lithographic parameters such as image placement error, focal shift, and loss of CD control. We show that thermal issues can be effectively managed to ensure that their impact on lithographic performance is maintained within design error budgets. (c) 1999 American Vacuum Society

  13. Performance of The Far Ultraviolet Spectroscopic Explorer Mirror Assemblies

    Science.gov (United States)

    Ohi, Raymond G.; Barkhouser, Robert H.; Conard, Steven J.; Friedman, Scott D.; Hampton, Jeffery; Moos, H. Warren; Nikulla, Paul; Oliveira, Cristina M.; Saha, Timo T.; Obenschain, Arthur (Technical Monitor)

    2000-01-01

    The Far Ultraviolet Spectroscopic Explorer is a NASA astrophysics satellite which produces high-resolution spectra in the far-ultraviolet (90.5-118.7 nm bandpass) using a high effective area and low background detectors. The observatory was launched on its three-year mission from Cape Canaveral Air Station on 24 June 1999. The instrument contains four coaligned, normal incidence, off-axis parabolic mirrors which illuminate separate Rowland circle spectrograph channels equipped with holographically ruled diffraction gratings and delay line microchannel plate detectors. The telescope mirrors have a 352 x 387 mm aperture and 2245 mm focal length and are attached to actuator assemblies, which provide on-orbit, tip, tilt, and focus control. Two mirrors are coated with silicon carbide (SiC) and two are coated with lithium fluoride over aluminum (Al:LiF). We describe mirror assembly in-flight optical and mechanical performance. On-orbit measurements of the far-ultraviolet point spread function associated with each mirror are compared to expectations based on pre-flight laboratory measurements and modeling using the Optical Surface Analysis Code and surface metrology data. On-orbit imaging data indicate that the mirrors meet their instrument-level requirement of 50 percent and 95 percent slit transmission for the high- and mid-resolution spectrograph entrance slits, respectively. The degradation of mirror reflectivity during satellite integration and test is also discussed. The far-ultraviolet reflectivity of the SiC- and AlLiF-coated mirrors decreased about six percent and three percent, respectively, between coating and launch. Each mirror is equipped with three actuators, which consist of a stepper motor driving a ball screw via a two-stage planetary gear train. We also discuss the mechanical performance of the mirror assemblies, including actuator performance and thermal effects.

  14. Tiny Ultraviolet Polarimeter for Earth Stratosphere from Space Investigation

    Science.gov (United States)

    Nevodovskyi, P. V.; Morozhenko, O. V.; Vidmachenko, A. P.; Ivakhiv, O.; Geraimchuk, M.; Zbrutskyi, O.

    2015-09-01

    One of the reasons for climate change (i.e., stratospheric ozone concentrations) is connected with the variations in optical thickness of aerosols in the upper sphere of the atmosphere (at altitudes over 30 km). Therefore, aerosol and gas components of the atmosphere are crucial in the study of the ultraviolet (UV) radiation passing upon the Earth. Moreover, a scrupulous study of aerosol components of the Earth atmosphere at an altitude of 30 km (i.e., stratospheric aerosol), such as the size of particles, the real part of refractive index, optical thickness and its horizontal structure, concentration of ozone or the upper border of the stratospheric ozone layer is an important task in the research of the Earth climate change. At present, the Main Astronomical Observatory of the National Academy of Sciences (NAS) of Ukraine, the National Technical University of Ukraine "KPI"and the Lviv Polytechnic National University are engaged in the development of methodologies for the study of stratospheric aerosol by means of ultraviolet polarimeter using a microsatellite. So fare, there has been created a sample of a tiny ultraviolet polarimeter (UVP) which is considered to be a basic model for carrying out space experiments regarding the impact of the changes in stratospheric aerosols on both global and local climate.

  15. The ultraviolet galactic background from TD-1 satellite observations

    International Nuclear Information System (INIS)

    Morgan, D.H.; Nandy, K.; Thompson, G.I.

    1976-01-01

    The background data from the S2/68 ultraviolet telescope on the TD-I satellite have been analysed. Using statistical tests those data contaminated by noise due to charged particles in the atmosphere have been discarded, and the remainder have been arranged to form ultraviolet profiles of the Galaxy. These profiles have been constructed at 2740 and 2350 A. The zodiacal light components of the total radiation field have been separated from the galactic components to give the intensity of the zodiacal light at elongation 90 0 as function of ecliptic latitude. The spectrum of the zodiacal light in the near ultraviolet is found to be redder than that of the Sun. The intensity of the diffuse galactic light as a function of galactic latitude has been obtained by subtraction of the zodiacal light and contributions due to faint stars calculated using an axi-symmetric model of the Galaxy. On comparison with predictions of the diffuse galactic light from a radiative transfer model it is found that the ratio of the albedos at 2350 and 2740 A is relatively insensitive to the model used, and is 0.73 +- 0.1. The albedo at 2740 A is found to be 0.65 +- 0.1 when g is assumed to be 0.75. (author)

  16. THE ULTRAVIOLET BRIGHTEST TYPE Ia SUPERNOVA 2011de

    International Nuclear Information System (INIS)

    Brown, Peter J.

    2014-01-01

    We present and discuss the ultraviolet (UV)/optical photometric light curves and absolute magnitudes of the Type Ia supernova (SN Ia) 2011de from the Swift Ultraviolet/Optical Telescope. We find it to be the UV brightest SN Ia yet observed—more than a factor of 10 brighter than normal SNe Ia in the mid-ultraviolet. We find that the UV/optical brightness and broad light curve evolution can be modeled with additional flux from the shock of the ejecta hitting a relatively large red giant companion separated by 6 × 10 13 cm. However, the post-maximum behavior of other UV-bright SNe Ia can also be modeled in a similar manner, including objects with UV spectroscopy or pre-maximum photometry which is inconsistent with this model. This suggests that similar UV luminosities can be intrinsic or caused by other forms of shock interaction. The high velocities reported for SN 2011de make it distinct from the UV-bright ''super-Chandrasekhar'' SNe Ia and the NUV-blue group of normal SNe Ia. SN 2011de is an extreme example of the UV variations in SNe Ia

  17. Extreme-Ultraviolet Vortices from a Free-Electron Laser

    Directory of Open Access Journals (Sweden)

    Primož Rebernik Ribič

    2017-08-01

    Full Text Available Extreme-ultraviolet vortices may be exploited to steer the magnetic properties of nanoparticles, increase the resolution in microscopy, and gain insight into local symmetry and chirality of a material; they might even be used to increase the bandwidth in long-distance space communications. However, in contrast to the generation of vortex beams in the infrared and visible spectral regions, production of intense, extreme-ultraviolet and x-ray optical vortices still remains a challenge. Here, we present an in-situ and an ex-situ technique for generating intense, femtosecond, coherent optical vortices at a free-electron laser in the extreme ultraviolet. The first method takes advantage of nonlinear harmonic generation in a helical undulator, producing vortex beams at the second harmonic without the need for additional optical elements, while the latter one relies on the use of a spiral zone plate to generate a focused, micron-size optical vortex with a peak intensity approaching 10^{14}  W/cm^{2}, paving the way to nonlinear optical experiments with vortex beams at short wavelengths.

  18. Null bactericidal effect of ultraviolet radiation emitted by LEDs.

    Directory of Open Access Journals (Sweden)

    Francisco Alcántara Muñoz

    2016-11-01

    Full Text Available This research has aimed to assess the bactericidal effect of ultraviolet light emitted by LEDS on the growth on Petri dishes of microorganisms whose legal limits in foods have been established. An electrically fed apparatus has been designed with precise timing and a camera to prevent light spillage, in which two ultraviolet radiation emission devices were connected by LED technology at different wavelengths: through an array of LEDS emitting at around 350nm, and a single specific emission LED at 280nm. 1000 cfu of E. Coli and S. aureus sown on PCA were used as prototypes of gram negative and positive bacteria, respectively, onto which ultraviolet light was radiated at different time intervals, by means of both devices, with the whole experiment being carried out in triplicate . In none of the three series of treatments at the two wavelengths were reductions in microbial growth observed. The series of sowings on PCA were done on unseeded plates in order to be able to discard the likelihood of subsequent recontamination.

  19. Ultraviolet radiation-induced carcinogenesis: mechanisms and experimental models

    International Nuclear Information System (INIS)

    Ramasamy, Karthikeyan; Shanmugam, Mohana; Balupillai, Agilan; Govindhasamy, Kanimozhi; Gunaseelan, Srithar; Muthusamy, Ganesan; Robert, Beualah Mary; Nagarajan, Rajendra Prasad

    2017-01-01

    Ultraviolet radiation (UVR) is a very prominent environmental toxic agent. UVR has been implicated in the initiation and progression of photocarcinogenesis. UVR exposure elicits numerous cellular and molecular events which include the generation of inflammatory mediators, DNA damage, epigenetic modifications, and oxidative damages mediated activation of signaling pathways. UVR-initiated signal transduction pathways are believed to be responsible for tumor promotion effects. UVR-induced carcinogenic mechanism has been well studied using various animal and cellular models. Human skin-derived dermal fibroblasts, epidermal keratinocytes, and melanocytes served as excellent cellular model systems for the understanding of UVR-mediated carcinogenic events. Apart from this, scientists developed reconstituted three-dimensional normal human skin equivalent models for the study of UVR signaling pathways. Moreover, hairless mice such as SKH-1, devoid of Hr gene, served as a valuable model for experimental carcinogenesis. Scientists have also used transgenic mice and dorsal portion shaved Swiss albino mice for UVR carcinogenesis studies. In this review, we have discussed the current progress in the study on ultraviolet B (UVB)-mediated carcinogenesis and outlined appropriate experimental models for both ultraviolet A- and UVB-mediated carcinogenesis. (author)

  20. Mechanism of ultraviolet photoconductivity in zinc oxide nanoneedles

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sanjeev [School of Information and Communication Engineering, and SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Gil-Ho [School of Information and Communication Engineering, and SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Sreenivas, K [Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India); Tandon, R P [Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India)

    2007-11-28

    Ultraviolet photoconductivity in zinc oxide (ZnO) nanoneedles grown on the surface of a multilayer structure comprised of ZnO film (50 nm)/Zn layer (20 nm)/ZnO film (2 {mu}m) fabricated on a stainless steel substrate using an unbalanced magnetron sputtering technique is reported. It was observed that the multilayered structure with ZnO nanoneedles exhibited enhanced ultraviolet photoconductivity in comparison to the ZnO films that were without nanoneedles. The enhancement in the photoconductivity is attributed to the increase in the quantum yield of the photogenerated charge carriers due to the presence of nanoneedles. A successive slow photoresponse transient following after a fast rise is due to the establishment of equilibrium between the charge carriers in the conduction band and the trapping centers created due to the shallow defects in the ZnO film. The observed photoresponse is critically analyzed on the basis of trapping levels created by the oxygen species during the high pressure deposition of the ZnO multilayer. Results show the promise of ZnO nanostructures in ultraviolet detection applications. (fast track communication)

  1. Mechanism of ultraviolet photoconductivity in zinc oxide nanoneedles

    International Nuclear Information System (INIS)

    Kumar, Sanjeev; Kim, Gil-Ho; Sreenivas, K; Tandon, R P

    2007-01-01

    Ultraviolet photoconductivity in zinc oxide (ZnO) nanoneedles grown on the surface of a multilayer structure comprised of ZnO film (50 nm)/Zn layer (20 nm)/ZnO film (2 μm) fabricated on a stainless steel substrate using an unbalanced magnetron sputtering technique is reported. It was observed that the multilayered structure with ZnO nanoneedles exhibited enhanced ultraviolet photoconductivity in comparison to the ZnO films that were without nanoneedles. The enhancement in the photoconductivity is attributed to the increase in the quantum yield of the photogenerated charge carriers due to the presence of nanoneedles. A successive slow photoresponse transient following after a fast rise is due to the establishment of equilibrium between the charge carriers in the conduction band and the trapping centers created due to the shallow defects in the ZnO film. The observed photoresponse is critically analyzed on the basis of trapping levels created by the oxygen species during the high pressure deposition of the ZnO multilayer. Results show the promise of ZnO nanostructures in ultraviolet detection applications. (fast track communication)

  2. Optical properties and electronic transitions of zinc oxide, ferric oxide, cerium oxide, and samarium oxide in the ultraviolet and extreme ultraviolet

    DEFF Research Database (Denmark)

    Pauly, N; Yubero, F; Espinós, J P

    2017-01-01

    Optical properties and electronic transitions of four oxides, namely zinc oxide, ferric oxide, cerium oxide, and samarium oxide, are determined in the ultraviolet and extreme ultraviolet by reflection electron energy loss spectroscopy using primary electron energies in the range 0.3-2.0 ke...

  3. Contrasting effects of ultraviolet-A and ultraviolet B exposure on induction of contact sensitivity in human skin

    DEFF Research Database (Denmark)

    Skov, Lone; Hansen, Henrik; Barker, J. N.

    1997-01-01

    Ultraviolet-B (UVB), in addition to direct effects on DNA, induces immunological changes in the skin that predispose to the development of skin cancer. Whether ultraviolet-A (UVA) induces similar changes is unknown. This effect can be investigated in humans in vivo using epicutaneous antigens...... as a model of tumour antigens. Volunteers (n = 46) were randomly assigned to received no sensitization, sensitization with the allergen diphenylcyclopropenone (DPCP) on non-UV-exposed normal skin, or sensitization with DPCP on skin exposed to three minimal erythema doses (MED) of either UVA or UVB radiation...... the immunization rate compared with sensitization on non-irradiated skin (P UVA radiation did not result in a decreased immunization rate compared with non-irradiated skin. These results indicate that in humans erythemagenic...

  4. Far-ultraviolet Bidirectional Photometry of Apollo Soil 10084: New Results from The Southwest Ultraviolet Reflectance Chamber (SwURC).

    Science.gov (United States)

    Raut, U.

    2017-12-01

    We report new measurements of the far-ultraviolet (115-180 nm) bidirectional reflectance of Apollo soil 10084 in the Southwest Ultraviolet Reflectance Chamber (SwURC). We find the bidirectional reflectance distribution function (BRDF) to be featureless in this wavelength region, though with a small blue slope. The angular distribution of the BRDF at Ly-α and 160 nm shows that this mature mare soil, containing nanophase Fe and enriched in Ti, anisotropically scatters light in the forward direction. The phase angle dependence of the BRDF is fitted with Hapke's photometric model with an additional diffuse-directional term. Future plans include measurements of mare and highland soils of differing maturity index (Is/FeO), water ice frost and lunar soil-ice aggregates. Such measurements will help constrain the abundance and distribution of the water ice on the illuminated lunar surface and dark permanently shadowed regions of the moon, as reported by LRO-LAMP.

  5. Pollen DNA repair after treatment with the mutagens 4-nitroquinoline-1-oxide, ultraviolet and near-ultraviolet irradiation, and boron dependence of repair

    International Nuclear Information System (INIS)

    Jackson, J.F.; Linskens, H.F.; Katholieke Universiteit Nijmegen

    1979-01-01

    Irradiation of dry, mature pollen from Petuna hybrida with near-ultraviolet light from an erythemal-sunlamp gave rise to a repair-like, unscheduled DNA synthesis during the early stages of in vitro germination. Like that brought about by far-ultraviolet light from a germicidal lamp, this DNA synthesis is enhanced by hydroxyurea added to the germination medium, and reduced by photoreactivating light given after ultraviolet irradiation and before germination begins. It is concluded that pollen, often receiving considerable exposure to sunlight, has, in addition to the protection afforded by the ultraviolet filtering effects of yellow pigments, also the capacity to repair ultraviolet produced changes in DNA, by both photoreactivation and dark repair processes. (orig./AJ) [de

  6. IUE's treasure-chest of the ultraviolet Universe

    Science.gov (United States)

    1997-11-01

    IUE was the most long-lived and (by a wide margin) the most productive satellite so far, in the history of space astronomy. After going into orbit on 26 January 1978, as a NASA-ESA-UK project, IUE was meant to operate for three years. More than eighteen years later, IUE still worked 24 hours a day, harvesting new knowledge for astronomers. The last observations were made from ESA's ground station at Villafranca, Spain, on 26 September 1996, and IUE was switched off four days later. Since then, team members at Villafranca and at NASAs Goddard Space Flight Center have used modern data-processing and information technology to recycle 100,000 ultraviolet spectra of comets, planets, stars, galaxies and quasars, acquired by IUE during its 18.5 years of operations. As a result, the IUE Final Archive is already available on-line via the Internet to hundreds of users who have registered to work with the data. The last few items (about 2 per cent of the total) will be added before the end of November. Also to be presented at the Sevilla conference is ESA's system called INES ("IUE Newly Extracted Spectra") which offers access, selection and distribution of data products, in a thoroughly user-friendly fashion. The IUE Final Archive is the third massive compendium made available to the worlds astronomers by ESA in 1997. The Hipparcos and Tycho Catalogues, released earlier in the year, give the positions of stars with unprecedented accuracy, thanks to ESA's Hipparcos satellite. "Space astronomy has set the example in providing a high standard of data quality and making the data accessible to the scientific community through archives", says Roger Bonnet, ESA's Scientific Director. "Now, ground-based observatories are following suit. The data legacy of IUE will be distributed to he community so that research on IUE data can continue long after the end of IUE's lifetime in space". Wonders of ultraviolet spectroscopy IUE analysed ultraviolet light, in a wavelength range from 1150

  7. Estimativa da radiação de onda longa atmosférica em áreas de floresta e de pastagem no sudoeste da Amazônia Estimate of the atmospheric long wave radiation in forest and pasture area in south west amazon

    Directory of Open Access Journals (Sweden)

    Leonardo José Gonçalves Aguiar

    2011-06-01

    Full Text Available A radiação de onda longa proveniente da atmosfera (Lin é a componente do balanço de radiação mais difícil de ser medida. Na Amazônia praticamente não existem medidas regulares dessa componente, mesmo sendo uma importante variável no cálculo do balanço de radiação à superfície e muito usada para alimentar modelos climáticos. Tendo em vista a necessidade desses dados, o objetivo do presente trabalho é avaliar o desempenho de sete equações na estimativa da Lin para dias de céu claro em áreas de floresta (Reserva Biológica do Jaru, 10º4'48''S; 61º55'48''W e de pastagem (Fazenda Nossa Senhora, 10º45'S; 62º21'W no sudoeste da Amazônia. Medidas de radiação de onda longa atmosférica realizadas no período de junho de 2005 a maio de 2006 foram comparadas com as estimativas. As equações testadas tiveram desempenho satisfatório apenas durante a estação seca. As condições de alta nebulosidade, dominantes na estação chuvosa, restringiram a quantidade de dados utilizados na avaliação das equações. As equações que utilizam informações de temperatura do ar e pressão de vapor d'água para a estimativa da Lin tiveram melhor desempenho em relação às que utilizam apenas a temperatura do ar. As equações de Brutsaert (1975, Idso (1981 e Prata (1996 foram as que apresentaram melhor desempenho, apresentando os maiores índices de concordância, e sendo, portanto, as equações mais indicadas para a estimativa da radiação de onda longa atmosférica no sudoeste da Amazônia.Atmospheric long wave radiation (Lin is the most difficult component of the radiation budget to be measured. In Amazonia there are very few regular measurements of this component, even though it is an important variable in the calculation of the surface radiation balance and frequently used in climate models. Given the need for such data, the objective of this study is to evaluate the performance of seven equations used for the estimation of Lin

  8. Observation of galactic ultraviolet by K-10-13 and K-9M-60 rockets

    International Nuclear Information System (INIS)

    Hayakawa, Sachio; Iwanami, Hideki; Kunieda, Hideyo; Nagase, Fumiaki; Yamashita, K.

    1978-01-01

    In order to determine the attitude of the rockets and to suppress the influence of ultraviolet ray to the proportional counters for the detection of X-ray, ultraviolet detectors were employed for the rocket experiments. The ultraviolet detectors were photomultipliers and proportional counters. The photomultipliers were Cs Te and sensitive to ultraviolet ray in the wavelength region below 3000 A. The proportional counters were filled with mixed gas of xylene and neon. In these observations, ultraviolet ray in the wavelength range from 1150 to 3200 A was detected. Ultraviolet sources of eta-UMα and Vela-Pup region were observed. The result showed that a sky map observed in this wavelength range was different from that observed in the longer wavelength range. (Yoshimori, M.)

  9. Ultraviolet-B-effects on plants: Spectra of harmful effects, primary damage and UV protective mechanisms

    International Nuclear Information System (INIS)

    Wellmann, E.; Beggs, C.; Moehle, B.; Schneider-Ziebert, U.; Steinmetz, V.; Koch, U.

    1986-01-01

    In two model systems of higher plants, damage caused by ultraviolet-B-radiation was analysed as to its mechanism of action and the spectral quantum efficiency. These investigations were to provide information on the relevance of such UV effects in cases of increased ultraviolet-B-irradiation owing to the destruction of ozone. The results indicate the very high tolerance of the plants to ultraviolet-B-radiation which obviously is the result of very effective protective mechanisms, and show at the same time that potential damage must already be reckoned with, given the current share of ultraviolet-B-radiation in solar radiation. Should ultraviolet-B-radiation be increased, then indirect damage to the plant from the destruction of ultraviolet protective mechanisms through UV-B-radiation will probably constitute a particular risk. (orig./MG) [de

  10. Flame retardancy and ultraviolet resistance of silk fabric coated by graphene oxide

    OpenAIRE

    Ji Yi-Min; Cao Ying-Ying; Chen Guo-Qiang; Xing Tie-Ling

    2017-01-01

    Silk fabrics were coated by graphene oxide hydrosol in order to improve its flame retardancy and ultraviolet resistance. In addition, montmorillonoid was doped into the graphene oxide hydrosol to further improve the flame retardancy of silk fabrics. The flame retardancy and ultraviolet resistance were mainly characterized by limiting oxygen index, vertical flame test, smoke density test, and ultraviolet protection factor. The synergistic effect of graphene oxide and montmorillonoid on the the...

  11. Threat of ultraviolet radiation to the eye--how to protect against it

    International Nuclear Information System (INIS)

    Pitts, D.G.

    1981-01-01

    The purpose of this paper is to discuss the effects of exposure of the eye to ultraviolet (UV) radiation and to provide information from which protective criteria and standards may be established. To accomplish this purpose, the article discusses ultraviolet radiation, absorption of UV radiation by the eye, the effects of ocular exposure to ultraviolet radiation, and how to protect the eye against exposure to UV radiation

  12. Analysis and design of the ultraviolet warning optical system based on interference imaging

    Science.gov (United States)

    Wang, Wen-cong; Hu, Hui-jun; Jin, Dong-dong; Chu, Xin-bo; Shi, Yu-feng; Song, Juan; Liu, Jin-sheng; Xiao, Ting; Shao, Si-pei

    2017-10-01

    Ultraviolet warning technology is one of the important methods for missile warning. It provides a very effective way to detect the target for missile approaching alarm. With the development of modern technology, especially the development of information technology at high speed, the ultraviolet early warning system plays an increasingly important role. Compared to infrared warning, the ultraviolet warning has high efficiency and low false alarm rate. In the modern warfare, how to detect the threats earlier, prevent and reduce the attack of precision-guided missile has become a new challenge of missile warning technology. Because the ultraviolet warning technology has high environmental adaptability, the low false alarm rate, small volume and other advantages, in the military field applications it has been developed rapidly. For the ultraviolet warning system, the optimal working waveband is 250 nm 280 nm (Solar Blind UV) due to the strong absorption of ozone layer. According to current application demands for solar blind ultraviolet detection and warning, this paper proposes ultraviolet warning optical system based on interference imaging, which covers solar blind ultraviolet (250nm-280nm) and dual field. This structure includes a primary optical system, an ultraviolet reflector array, an ultraviolet imaging system and an ultraviolet interference imaging system. It makes use of an ultraviolet beam-splitter to achieve the separation of two optical systems. According to the detector and the corresponding application needs of two visual field of the optical system, the calculation and optical system design were completed. After the design, the MTF of the two optical system is more than 0.8@39lp/mm.A single pixel energy concentration is greater than 80%.

  13. Ion chromatography with the indirect ultraviolet detection of alkali metal ions and ammonium using imidazolium ionic liquid as ultraviolet absorption reagent and eluent.

    Science.gov (United States)

    Liu, Yong-Qiang; Yu, Hong

    2016-08-01

    Indirect ultraviolet detection was conducted in ultraviolet-absorption-agent-added mobile phase to complete the detection of the absence of ultraviolet absorption functional group in analytes. Compared with precolumn derivatization or postcolumn derivatization, this method can be widely used, has the advantages of simple operation and good linear relationship. Chromatographic separation of Li(+) , Na(+) , K(+) , and NH4 (+) was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid/organic solvent as the mobile phase, in which imidazolium ionic liquids acted as ultraviolet absorption reagent and eluting agent. The retention behaviors of four kinds of cations are discussed, and the mechanism of separation and detection are described. The main factors influencing the separation and detection were the background ultraviolet absorption reagent and the concentration of hydrogen ion in the ion chromatography-indirect ultraviolet detection. The successful separation and detection of Li(+) , Na(+) , K(+) , and NH4 (+) within 13 min was achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.02, 0.11, 0.30, and 0.06 mg/L, respectively. A new separation and analysis method of alkali metal ions and ammonium by ion chromatography with indirect ultraviolet detection method was developed, and the application range of ionic liquid was expanded. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. The roles of different repair mechanisms in the ultraviolet resistance of Micrococcus luteus

    International Nuclear Information System (INIS)

    Zherebtsov, S.V.; Tomilin, N.V.

    1982-01-01

    In ultraviolet-irradiated Micrococcus luteus wild type the replication of DNA was not interrupted at every pyrimidine dimer, in contrast to that in ultraviolet-sensitive G7 and some other mutants. The contribution of uninterrupted replication to the ultraviolet resistance of M. luteus proved to be equal to the contributions of excision repair and inducible postreplication repair. It was found that some postreplication gaps could be filled by constitutive pathways of postreplication repair when inducible pathways were suppressed by chloramphenicol. Prolonged treatment with chloramphenicol was shown to block not only inducible repair but also other processes essential for ultraviolet irradiation survival. (Auth.)

  15. Flame retardancy and ultraviolet resistance of silk fabric coated by graphene oxide

    Directory of Open Access Journals (Sweden)

    Ji Yi-Min

    2017-01-01

    Full Text Available Silk fabrics were coated by graphene oxide hydrosol in order to improve its flame retardancy and ultraviolet resistance. In addition, montmorillonoid was doped into the graphene oxide hydrosol to further improve the flame retardancy of silk fabrics. The flame retardancy and ultraviolet resistance were mainly characterized by limiting oxygen index, vertical flame test, smoke density test, and ultraviolet protection factor. The synergistic effect of graphene oxide and montmorillonoid on the thermal stabilization property of the treated silk fabrics was also investigated. The results show that the treated silk fabrics have excellent flame retardancy, thermal stability, smoke suppression, and ultraviolet resistance simultaneously.

  16. Experimental studies of self-suppression of vacuum ultraviolet generation in Xe

    International Nuclear Information System (INIS)

    Judish, J.P.; Allman, S.L.; Garrett, W.R.; Payne, M.G.

    1988-11-01

    Vacuum ultraviolet light in the range 116 nm to 117 nm was produced by using a two-photon resonant four-wave mixing scheme in Xe. The buildup of coherent cancellation of the two-photon resonant transition employed in the generation of the vacuum ultraviolet, with resulting limitations imposed on the achievable vacuum ultraviolet intensity was investigated. Under certain predicted conditions, increases in the intensity of one of the pumping beams, ∼1500 nm infrared, or tuning this beam towards resonance with the 5p 5 7s(3/2) 1 level of Xe led, not to increases, but decreases in the vacuum ultraviolet generated. 3 refs., 3 figs

  17. Photochemical Cyclopolymerization of Polyimides in Ultraviolet Ridgidizing Composites for Use in Inflatable Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This innovation uses photochemical cyclopolymerization of polyimides to manufacture ultraviolet rigidizable composites for use in RIS (ridgidizing inflatable)...

  18. Isolation and identification of previtamin D3 from the skin of rats exposed to ultraviolet irradiation

    International Nuclear Information System (INIS)

    Holick, M.F.; Richtand, N.M.; McNeill, S.C.; Holick, S.A.; Frommer, J.E.; Henley, J.W.; Potts, J.T. Jr.

    1979-01-01

    The process of the photolytic activation of vitamin D precursor(s) in the skin has been elucidated by a detailed analysis of the products formed after ultraviolet light exposure. The photolytic product isolated from the skin of rats exposed to ultraviolet irradiation was identified as previtamin D 3 by several criteria including its characteristic ultraviolet absorption spectrum, mass spectrum, and thermal isomerization to vitamin D 3 , which itself was identified also by mass spectroscopy. Vitamin D 3 per se was not formed by ultraviolet irradiation-vitamin D 3 arises exclusively from the thermal conversion of previtamin D 3 . Detectable amounts of lumisterol 3 or tachysterol 3 were not seen

  19. Ultraviolet asymptotic behavior of the photon propagator in dimensionally regularized quantum electrodynamics

    International Nuclear Information System (INIS)

    Krasnikov, N.V.

    1991-01-01

    Study of the ultraviolet behavior of asymptotically nonfree theories is one of the most important problems of quantum field theory. Unfortunately, not too much is known about the ultraviolet properties in asymptotically nonfree theories; the main obstacle is the growth of the effective coupling constant in the ultraviolet region, which renders perturbation theory inapplicable. It is shown that in quantum electrodynamics in n = 4 + 2 var-epsilon space-time (var-epsilon > 0) the photon propagator has the ultraviolet asymptotic behavior D(k 2 ) ∼ (k 2 ) -1-var-epsilon . In the case var-epsilon R ≤ -3π var-epsilon + O(var-epsilon 2 )

  20. GLOBAL SIMULATION OF AN EXTREME ULTRAVIOLET IMAGING TELESCOPE WAVE

    International Nuclear Information System (INIS)

    Schmidt, J. M.; Ofman, L.

    2010-01-01

    We use the observation of an Extreme Ultraviolet Imaging Telescope (EIT) wave in the lower solar corona, seen with the two Solar Terrestrial Relations Observatory (STEREO) spacecraft in extreme ultraviolet light on 2007 May 19, to model the same event with a three-dimensional (3D) time-depending magnetohydrodynamic (MHD) code that includes solar coronal magnetic fields derived with Wilcox Solar Observatory magnetogram data, and a solar wind outflow accelerated with empirical heating functions. The model includes a coronal mass ejection (CME) of Gibson and Low flux rope type above the reconstructed active region with parameters adapted from observations to excite the EIT wave. We trace the EIT wave running as circular velocity enhancement around the launching site of the CME in the direction tangential to the sphere produced by the wave front, and compute the phase velocities of the wave front. We find that the phase velocities are in good agreement with theoretical values for a fast magnetosonic wave, derived with the physical parameters of the model, and with observed phase speeds of an incident EIT wave reflected by a coronal hole and running at about the same location. We also produce in our 3D MHD model the observed reflection of the EIT wave at the coronal hole boundary, triggered by the magnetic pressure difference between the wave front hitting the hole and the boundary magnetic fields of the coronal hole, and the response of the coronal hole, which leads to the generation of secondary reflected EIT waves radiating away in different directions than the incident EIT wave. This is the first 3D MHD model of an EIT wave triggered by a CME that includes realistic solar magnetic field, with results comparing favorably to STEREO Extreme Ultraviolet Imager observations.

  1. Ultraviolet modification of Chlamydomonas reinhardtii for carbon capture

    Directory of Open Access Journals (Sweden)

    Gopal NS

    2016-04-01

    Full Text Available Nikhil S Gopal,1 K Sudhakar2 1The Lawrenceville School, Lawrenceville, NJ, USA; 2Bioenergy Laboratory, Malauna Azad National Institute of Technology, Bhopal, India Purpose: Carbon dioxide (CO2 levels have been rising rapidly. Algae are single-cell organisms with highly efficient CO2 uptake mechanisms. Algae yield two to ten times more biomass versus terrestrial plants and can grow nearly anywhere. Large scale CO2 sequestration is not yet sustainable due to high amounts of nitrogen (N and phosphate (P needed to grow algae in media. Methods: Mutant strains of Chlamydomonas reinhardtii were created using ultraviolet light (2.2–3 K J/m2 and natural selection using media with 20%–80% lower N and P compared to standard Sueoka's high salt medium. Strains were selected based upon growth in media concentrations varying from 20% to 80% less N/P compared to control. Biomass was compared to wild-type control (CC-125 using direct counts, optical density dry weight, and mean doubling time. Results: Mean doubling time was 20 and 25 hours in the low N and N/P strains, respectively (vs 66 hours in control. Using direct counts, growth rates of mutant strains of low N and N/P cultures were not statistically different from control (P=0.37 and 0.70, respectively. Conclusion: Two new strains of algae, as well as wild-type control, were able to grow while using 20%–40% less N and P. Ultraviolet light-based modification of algae is an inexpensive and alternative option to genetic engineering techniques. This technique might make larger scale biosequestration possible. Keywords: biosequestration, ultraviolet, carbon sequestration, carbon capture, algae

  2. Effect of ultraviolet light on creatinine measurement in jaundiced specimens

    International Nuclear Information System (INIS)

    Nisbet, J.A.; D'Souza, R.

    1986-01-01

    During initial evaluation of a creatinine method using the RA-1000 analyser, experiments with addition of bilirubin indicated negligible interference. However the finding of a 'zero' creatinine value in an extremely jaundiced specimen prompted to re-examine the method. In contrast to earlier findings with normal plasma containing added bilirubin, the authors found that plasma from moderately or severely jaundiced patients gave creatinine values lower than those obtained with a reference method. Since bilirubin has been implicated in the interference, the authors studied the effect of destroying bilirubin with ultraviolet light to see if this provided a practical solution to the problem. (Auth.)

  3. Diarylethene microcrystals make directional jumps upon ultraviolet irradiation

    International Nuclear Information System (INIS)

    Colombier, I.; Spagnoli, S.; Corval, A.; Baldeck, P. L.; Giraud, M.; Leaustic, A.; Yu, P.; Irie, M.

    2007-01-01

    Microcrystals of a diarylethene {1,2-bis[5 ' -methyl-2 ' -(2 '' -pyridyl)thiazolyl]perfluorocyclo-pentene } undergo jumps upon photoirradiation. These photochromic crystals present molecular structural changes upon irradiation with ultraviolet light because of reversible photocyclization reactions. When the energy absorbed by crystals reaches about 10 μJ, the uniaxial stress induced in the crystal lattice relaxes through directional jumps. If one prevents crystals from jumping, then parallel, equidistant cracks appear on crystal surfaces. These photomechanical effects could result from a Grinfeld surface instability

  4. Ultraviolet - status of knowledge on exposure and health risks

    International Nuclear Information System (INIS)

    Dervault, Anne Marie; Secretan, Beatrice; Guinot, Christiane; Bazex, Jacques; Donadieu, Jean; Dore, Jean Francois; Cesarini, Jean Pierre; Aleth Richard, Marie; Leccia, Marie Therese; Autier, Philippe; Cesarini, Jean Pierre; Beani, Jean Claude; Grob, Jean Jacques; Wald, Lucien; Dore, Jean Francois; Casiniere, Alain de la; Dixsaut, Gilles; Guenel, Pascal; Choulika, Sophie; Pirard, Philippe; Bastuji-Garin, S.; Beani, J.C.; Brin, A.J.; Cadet, J.; Corre, M.F.; Frelon, J.H.; Grob, Jean Jacques; Jeanmougin, M.; Martini-Morel, M.C.; Meunier, L.; Marty, J.P.; Revuz, J.; Reynier, J.P.; Roelands, R.; Stoebner, A.; Vian, L.

    2005-05-01

    After having recalled some physical aspects of ultraviolet radiations (presence in solar radiation, artificial UV radiation, measurement, metrology, UV index, boundary limits), this report describes the biological and health effects of UV radiations (analysis methodology, recall of previous expert reports, biological effects, health effects), addresses human behaviour with respect to UV radiation and exposure to UV radiation, discusses the relationship between cosmetics and UV radiation. It presents the various European and international positions with respect to UV emitting devices (evolution of standards, regulations). Some recommendations are made regarding solar exposure, sun-tanning installations, and other domestic or industrial sources

  5. Broadband stimulated Raman spectroscopy in the deep ultraviolet region

    Science.gov (United States)

    Kuramochi, Hikaru; Fujisawa, Tomotsumi; Takeuchi, Satoshi; Tahara, Tahei

    2017-09-01

    We report broadband stimulated Raman measurements in the deep ultraviolet (DUV) region, which enables selective probing of the aromatic amino acid residues inside proteins through the resonance enhancement. We combine the narrowband DUV Raman pump pulse (1000 cm-1) to realize stimulated Raman measurements covering a >1500 cm-1 spectral window. The stimulated Raman measurements for neat solvents, tryptophan, tyrosine, and glucose oxidase are performed using 240- and 290-nm Raman pump, highlighting the high potential of the DUV stimulated Raman probe for femtosecond time-resolved study of proteins.

  6. Ultraviolet vision in birds: the importance of transparent eye media

    OpenAIRE

    Lind, Olle; Mitkus, Mindaugas; Olsson, Peter; Kelber, Almut

    2014-01-01

    Ultraviolet (UV)-sensitive visual pigments are widespread in the animal kingdom but many animals, for example primates, block UV light from reaching their retina by pigmented lenses. Birds have UV-sensitive (UVS) visual pigments with sensitivity maxima around 360–373 nm (UVS) or 402–426 nm (violet-sensitive, VS). We describe how these pigments are matched by the ocular media transmittance in 38 bird species. Birds with UVS pigments have ocular media that transmit more UV light (wavelength of ...

  7. Effect of ultraviolet illumination on metal oxide resistive memory

    KAUST Repository

    Duran Retamal, Jose Ramon

    2014-12-22

    We investigate the photoelectrical and resistive switching properties of Pt/ZnO/Pt capacitor operated in unipolar mode under ultraviolet (UV) illumination. The oxygen photodesorption under UV illumination explains the photoconduction observed in initial and high resistance states. Meanwhile, oxygen readsorption at surface-related defects justifies the different photoresponses dynamics in both states. Finally, UV illumination significantly reduces the variations of resistance in high resistance state, set voltage and reset voltage by 58%, 33%, and 25%, respectively, stabilizing Pt/ZnO/Pt capacitor. Our findings in improved switching uniformity via UV light give physical insight into designing resistive memory devices.

  8. Polishing Sapphire Substrates by 355 nm Ultraviolet Laser

    Directory of Open Access Journals (Sweden)

    X. Wei

    2012-01-01

    Full Text Available This paper tries to investigate a novel polishing technology with high efficiency and nice surface quality for sapphire crystal that has high hardness, wear resistance, and chemical stability. A Q-switched 355 nm ultraviolet laser with nanosecond pulses was set up and used to polish sapphire substrate in different conditions in this paper. Surface roughness Ra of polished sapphire was measured with surface profiler, and the surface topography was observed with scanning electronic microscope. The effects of processing parameters as laser energy, pulse repetition rate, scanning speed, incident angle, scanning patterns, and initial surface conditions on surface roughness were analyzed.

  9. Sensitivity of ice-nucleating bacteria to ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Obata, Hitoshi; Tanahashi, Shinji; Kawahara, Hidehisa (Kansai Univ., Suita, Osaka (Japan). Faculty of Engineering)

    1992-01-01

    The effect of ultraviolet (UV) irradiation on the ice-nucleating activity of the ice-nucleating bacteria was examined. Bacterial suspension was irradiated with UV (254 nm, 6Wx2) for 5 min at a distance of 20 cm from UV source. Although no viable cells were detected, the ice-nucreating activity of the cells was not affected. Furthermore, after UV irradiation for 3 hr, the ice-nucleating activity of Pseudomonas fluorescens and P. syringae was only slightly decreased, although that of P. viridiflava and Erwinia herbicola was significantly lowered. We succeeded in killing the ice-nucleating bacteria, while retaining their ice-nucleating activity with UV irradiation. (author).

  10. Ultraviolet Studies of Jupiter's Hydrocarbons and Aerosols from Galileo

    Science.gov (United States)

    Gladstone, G. Randall

    2001-01-01

    This is the final report for this project. The purpose of this project was to support PI Wayne Pryor's effort to reduce and analyze Galileo UVS (Ultraviolet Spectrometer) data under the JSDAP program. The spectral observations made by the Galileo UVS were to be analyzed to determine mixing ratios for important hydrocarbon species (and aerosols) in Jupiter's stratosphere as a function of location on Jupiter. Much of this work is still ongoing. To date, we have concentrated on analyzing the variability of the auroral emissions rather than the absorption signatures of hydrocarbons, although we have done some work in this area with related HST-STIS data.

  11. Ultraviolet light: sterile water without chlorine smell and taste

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The use of chlorine and hypochlorite is necessary in larger waterworks, but it is a disadvantage in smaller plants, where overtreatment easily leads to smell and taste of chlorine in the water. Ultraviolet light with a wavelength of 2535 Angstrom gives 100% disinfection with a dose of 10 mWs/cm 2 for all known bacteria. In practice a dose of 40 mWs/cm 2 and an irradiation time of 15 minutes is desireable. A standard unit utilising six UV light tubes arranged concentrically around a quartz tube, through which the water flows, is described briefly. (JIW)

  12. Photoinactivation of Propionibacterium acnes by near-ultraviolet light

    International Nuclear Information System (INIS)

    Kjeldstad, B.

    1984-01-01

    Photodestruction of Propionibacterium acnes was investigated by broad-band near-ultraviolet light. The inactivation of the bacteria was found to be oxygen dependent, and without O 2 practically no photoinactivation occurred. D 2 O caused an increased inactivation (D 10 = 5 kJ/m 2 in D 2 O as compared to D 10 = 11 kJ/m 2 in normal water). Decreased temperature during illumination increased the ability to form colonies. The results are compared with corresponding results for other types of cells and the destruction mechanism is discussed. (orig.)

  13. Ultraviolet irradiation of water - an alternative to chlorination

    International Nuclear Information System (INIS)

    Andvik, N.-O.

    1977-01-01

    The advantages of ultraviolet radiation of wavelength 2500-2600 Aangstroem are discussed and the principal considerations to be taken into account in the planning of an irradiation plant are presented. The design of a typical irradiation anit is illustrated and described briefly. Such plants were first used in Switzerland and are widely used there and in Austria. In the course of the past two years several plants have been installed in Norway. They are suitable both for treatment of drinking water and pretreated sewage, but less satisfactory for swimming pools. (JIW)

  14. Health effects of exposure to ultraviolet and infrared radiation

    International Nuclear Information System (INIS)

    Thuerauf, J.R.

    1979-01-01

    A working group on the Health Effects of Exposure to Ultraviolet and Infrared Radiation met in Sofia (Bulgaria) from February 21-25, 1978. The conference was organized by the European Regional Bureau of the World Health Organization, WHO, in cooperation with the Bulgarian government. The main task for the participants was the revision and discussion of two guidelines. A Manual on Nonionizing Radiation Protection will be made available in 1979 to governmental and official organs to support them in establishing standards for the control of radiation. (orig.) [de

  15. Large area, surface discharge pumped, vacuum ultraviolet light source

    Science.gov (United States)

    Sze, R.C.; Quigley, G.P.

    1996-12-17

    Large area, surface discharge pumped, vacuum ultraviolet (VUV) light source is disclosed. A contamination-free VUV light source having a 225 cm{sup 2} emission area in the 240-340 nm region of the electromagnetic spectrum with an average output power in this band of about 2 J/cm{sup 2} at a wall-plug efficiency of approximately 5% is described. Only ceramics and metal parts are employed in this surface discharge source. Because of the contamination-free, high photon energy and flux, and short pulse characteristics of the source, it is suitable for semiconductor and flat panel display material processing. 3 figs.

  16. Mutations induced by ultraviolet radiation affecting virulence in Puccinia striiformis

    International Nuclear Information System (INIS)

    Shang Hongsheng; Jing Jinxue; Li Zhenqi

    1994-01-01

    Uredospores of parent culture, cy 29-1, were treated by ultraviolet radiation and mutations to virulent were tested on resistant wheat cultivars inoculated with treated spores. 7 mutant cultures virulent to the test cultivars were developed with estimated mutation rate 10~6~10~4. The virulence of mutant cultures was different from the all known races of stripe rust. Resistance segregation to mutant cultures was detected in two test cultivars. The results suggested that mutation was important mechanism of virulence variation operative in asexual population of rust fungi

  17. Oxidation of graphene in ozone under ultraviolet light

    KAUST Repository

    Cheng, Yingchun

    2012-08-17

    Based on first-principles calculations, the process of grapheneoxidation in ozone under ultraviolet light is explored by studying the effects of O(3P) on the structural and electronic properties of a graphene sheet. On initial absorption of O(3P), an epoxy group is formed on the graphene sheet and the Dirac cone is shifted away from the Brillouin zone corners without carrier doping. When the oxidation progresses, an adjacent C-C bond is broken, a vacancy is formed, and CO and/or CO2 molecules are released.

  18. Determination of organic compounds in water using ultraviolet LED

    Science.gov (United States)

    Kim, Chihoon; Ji, Taeksoo; Eom, Joo Beom

    2018-04-01

    This paper describes a method of detecting organic compounds in water using an ultraviolet LED (280 nm) spectroscopy system and a photodetector. The LED spectroscopy system showed a high correlation between the concentration of the prepared potassium hydrogen phthalate and that calculated by multiple linear regression, indicating an adjusted coefficient of determination ranging from 0.953-0.993. In addition, a comparison between the performance of the spectroscopy system and the total organic carbon analyzer indicated that the difference in concentration was small. Based on the close correlation between the spectroscopy and photodetector absorbance values, organic measurement with a photodetector could be configured for monitoring.

  19. Ultraviolet light: sterile water without chlorine smell and taste

    Energy Technology Data Exchange (ETDEWEB)

    1977-02-14

    The use of chlorine and hypochlorite is necessary in larger waterworks, but it is a disadvantage in smaller plants, where overtreatment easily leads to smell and taste of chlorine in the water. Ultraviolet light with a wavelength of 2535 Angstrom gives 100% disinfection with a dose of 10 mWs/cm/sup 2/ for all known bacteria. In practice a dose of 40 mWs/cm/sup 2/ and an irradiation time of 15 minutes is desireable. A standard unit utilising six UV light tubes arranged concentrically around a quartz tube, through which the water flows, is described briefly.

  20. Ultra-violet emission in Ho:ZBLAN fiber

    International Nuclear Information System (INIS)

    Kowalska, M.; Klocek, G.; Piramidowicz, R.; Malinowski, M.

    2004-01-01

    We report on the short wavelength (green, blue, and ultra-violet (UV)) emission in trivalent holmium doped fluoro-zirconate fiber (Ho 3+ :ZBLAN) under direct and upconversion pumping. Efficient red to UV upconversion has been observed using 647 nm cw pumping by krypton ion laser. A close to cubic UV signal intensity dependence on incident red pump power was determined, confirming the three-photon character of the observed process. The responsible upconversion mechanisms were investigated and shown to be excited state absorption (ESA) via low-lying 5 I 7 and 5 I 6 sates. Dynamics of the involved excited states have been studied under pulsed laser excitation