Influence of plasma dynamics of a sodium discharge on the radiation spectrum

The main directions in improving the color rendering index of a high-pressure sodium discharge are analyzed theoretically. The spectral characteristics of the sodium-mercury column in the pulsed and ac modes are compared. The effect of an increase in the xenon pressure and the introduction of rubidium and cesium into the charge on the radiation characteristics of pulsed sodium lamps is studied.     

Effect of long-term exposure of rabbits to ultraviolet radiation on the level, creation and inactivation of kinins in blood

Experimental rabbits were exposed to ultraviolet radiation during 6 weeks once daily for 10 minutes (from a high-pressure. Hanau Q 400 mercury lamp with a Schott UG 2 T filtre and absorber of long-wave radiation using ultraviolet rays of 405--289 nm wavelength and 134 000 erg/sec/cm2 power, directed onto skin with cropped hair of the back). Under general anaesthesia with pentothal blood samples were obtained from the carotid artery in 4 groups of 8 rabbits in each group. The blood samples were taken from non-exposed control rabbits and from the experimental groups after 2, 4 and 6 weeks of exposure. In the samples the levels of free kinins in the blood, and kininogen, and the activity of kallikreins and kininases in the plasma were determined. In the irradiated animals a progressive rise of free kinins most pronounced after 6 weeks was observed, and other findings included: a fall of kininogen level particularly steep after 2 weeks, very small rise in the activity of kallikreins, and progressing reduction of the activity of kininase, particularly steep after 2 weeks.     

Certain photooxidized derivatives of tryptophan bind with very high affinity to the Ah receptor and are likely to be endogenous signal substances

The purpose of the present study was to determine whether ultraviolet light (UV) irradiation of amino acids produces compounds with affinity for the Ah receptor. Aqueous solutions of L-tryptophan were exposed to radiation from an unfiltered high-pressure mercury lamp. The photoproducts formed were solvent-extracted or concentrated on Sep-Pak C18 cartridges. The concentrated extracts or eluants were treated for their ability to compete with 3H-labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Binding was assayed in liver cytosolic preparations from Sprague-Dawley rats using a technique based on hydroxylapatite separation. Photoproducts with receptor affinity were formed in a time-dependent manner. Histidine and tryptamine also gave products upon UV irradiation that competed with TCDD. Commercial tryptophan, at least aged, contained trace amounts of impurities with receptor affinity. Analysis by TLC and high-pressure liquid chromatography of the photo-products of tryptophan showed a minimum of three different binding compounds. Two of the products were studied in greater detail. One of them, showing UV absorbance and yellow fluorescence, gave a molecular ion (M+) of 284 and the other gave M+ 312 but showed little UV absorption and fluorescence. The concentration, based on mass spectrometry quantifications, of the two compounds that displaced more than 50% of TCDD was found to be extremely low, giving Kd values of 0.44 nM (M+ 312) and 0.07 nM (M+ 284). The existence of high affinity receptors for oxidized amino acids is postulated and their possible role in the proliferative cellular responses to TCDD and tryptophan is discussed briefly.     

Determination of the spatial characteristics of an RF electrodeless discharge by the method of emission tomography

The spatial distribution of the density of mercury atoms in the 7³ S state in a spherical RF electrode-less gas-discharge lamp is reconstructed by the method of emission tomography. The local values of the corresponding emission coefficients, which are proportional to the density of mercury atoms in the 7³ S state, are determined from integral (over the plasma volume) measurements of the lamp radiation at a wavelength of 546.1 nm with the help of an algorithm based on the maximum entropy method. The results obtained show that, for all of the operating modes under study, the profile of the density of mercury atoms in the 7³ S state has a minimum in the center of the lamp and a maximum near its wall. At a generator current of 100 mA and cold-spot temperature of 41°C, the density of mercury atoms in the 7³ S state is observed to drop substantially both in the center of the lamp and near its wall, the density in the center being reduced to almost zero. An explanation of this phenomenon is proposed.     

Photoreaction of methyl and phenyl 4,6-O-benzylidene-2,3-dideoxy-2-C-p-tolylsulfonyl-beta-D-erythro-hex-2-enopyranosides in methanol

The title compounds were irradiated with a high-pressure mercury lamp in methanol to give 2-C-hydroxymethyl derivatives having the gluco, altro, and allo configurations as well as an S(N)2' product. Equatorial attack of a hydroxymethyl radical slightly predominated over axial attack. During chromatographic separation on a silica gel column, partial migration of the 4,6-O-benzylidene group in the gluco and altro products occurred to yield the 3',4-O-benzylidene derivatives.     

Phototherapy and dithranol treatment of psoriasis: new lamps for old.

The response of psoriasis to ultraviolet radiation and dithranol was compared with the response to dithranol alone in 24 patients. The difference in rate of response, measured as change in plaque thickness, and the difference in time to complete clearance of psoriasis between irradiated and non-irradiated forearm lesions was significantly greater for patients treated using fluorescent lamps with negligible ultraviolet C emission (Wolff Helarium) than for those patients treated with a medium pressure mercury arc lamp (p less than 0.01) or an array of fluorescent sunlamps (p less than 0.05). The difference in therapeutic response shows that ultraviolet B phototherapy is effective when used in combination with dithranol. Nevertheless, radiation sources with substantial ultraviolet C emission, such as the medium pressure mercury arc lamp most commonly used to treat psoriasis in the United Kingdom, have little effect because delivery of therapeutic doses of ultraviolet B is limited by erythema induced by ultraviolet C.     

The influence of the wavelength of ultraviolet radiation on survival,mutation induction and DNA repair in irradiated chinese hamster cells

Chinese hamster ovary cells were used to compare the cytotoxicity and mutagenicity of far-UV radiation emitted by a low-pressure mercury, germicidal lamp (wavelength predominantly 254 nm) with that of near-UV radiation emitted by a fluorescent lamp with a continuous spectrum (Westinghouse “Sun Lamp”), of which only the radiation with wavelengths greater than 290 nm or greater than 310 nm was transmitted to the cells. The radiation effects were compared on the basis of an equal number of pyrimidine dimers, the predominant lesion induced in DNA by far-UV, for the induction of which much more energy is needed with near-UV than with 254-nm radiation.The numbers of dimers induced were determined by a biochemical method detecting UV-endonuclease-susceptible sites. The equivalence of these sites with pyrimidine dimers was established, qualitatively and quantitatively, in studies with enzymic photoreactivation in vitro and chromatographic analysis of dimers.On the basis of induced dimers, more cells were killed by >310-nm UV than by >290-nm UV; both forms of radiation were more cytotoxic than 254-nm UV when equal numbers of dimers were induced. Moreover, 5–6 times as many mutants were induced per dimer by >310-nm UV than by >290-nm UV; the latter appeared approximately as mutagenic as 254-nm UV. The differences in lethality and mutagenicity were not caused by differences in repair of dimers: cells with an equal number of dimers induced by either 254-nm or near-UV showed the same removal of sites susceptible to a UV endonuclease specific for dimers, as well as an identical amount of repair replication.The results indicate that near-UV induces, besides pyrimidine dimers, other lesions that appear to be of high biological significance.     

Study of the optical properties of a pulse-periodic high-pressure cesium discharge

Results of theoretical and experimental studies of the optical spectrum of a pulse-periodic high-pressure cesium discharge are presented. The results of calculations are in good agreement with experimental data. The possibility of creating an efficient light source based on recombination emission from the discharge plasma is demonstrated. The formation mechanisms of the continuous spectrum of discharge radiation are considered.     

The protection of DNA in blood leukocytes from damaging action of ultraviolet radiation using the “Useful Sun” strategy

The damaging effects of light that was emitted by a DRSh250-3 mercury lamp on the DNA of mouse blood leukocytes was studied in vitro. It was shown that the main DNA damage is due to the action of UVB radiation (280–320 nm). Under the combined effects of the UV radiation and the orange–red fluorescent component it was found that the additional fluorescent light with the spectral maximum at 625 nm from nanoluminophore materials (quantum dots that are based on CdSe/ZnS, CdSe/CdS/ZnS) protected the cellular DNA from the damaging effect of UV radiation. Using nanomolar concentrations of hydrogen peroxide, the hypothesis of the role of reactive oxygen species in the protective effects of the red–orange light was tested in vitro. It was shown for the first time that the mechanisms of the protective effects are associated with the induction of an adaptive response by nanomolar concentrations of hydrogen peroxide that are induced by the orange–red light.     

Effects of adding calcium and sodium salts to field soils on the incidence of clubroot

The effect on clubroot of the addition to a mineral soil of calcium carbonate, calcium sulphate and sodium carbonate was studied in two field experiments during a 3-yr period. Applications of calcium carbonate (ground limestone) at 10 or 20 t/ha increased the soil pH from 6×7 to 7×9; sodium carbonate at 7×5 t/ha to pH 8×3 and calcium sulphate (gypsum) at 20 t/ha caused a slight depression in pH to 6×6. 98% of cabbage plants showed clubroot symptoms in the untreated plots after 3 yr and the percentages were 0×7, 1×6 and 66×6 for the calcium carbonate, sodium carbonate and calcium sulphate treatments respectively. Yields were significantly increased by all three materials. There were no significant differences in disease incidence or in yield when calcium carbonate was used at 10 or 20 t/ha either applied as a single application or as two half-rate applications. Soil from the calcium carbonate treated plots was used in a greenhouse experiment where the addition of inoculum of Plasmodiophora brassicae resulted in a large increase in clubroot incidence. There was no evidence that a biological suppressor was present in the high pH, low disease incidence soils.     

光催化氧化降解制药废水中头孢曲松钠的研究

以二氧化钛(TiO₂)为光催化剂,分别采用高压汞灯和反射镝灯为紫外光和模拟日光光源,对头孢曲松钠进行光催化降解,用紫外光谱跟踪其光催化降解过程。考察了光催化体系中光源、催化剂用量、光照时间、电子受体以及其他离子的存在对光催化降解过程的影响。结果显示,当反应物初始浓度500mg·L^-1,在高压汞灯和反射镝灯条件下反应5小时后,在催化剂用量分别为2.5g·L^-1和2.0g·L^-1时对头孢曲松钠的降解效果最好,分别达到93.4%和73.8%。体系中加入电子受体能促进光催化反应速率,而一些无机离子如HCO₃^-、SO₄^2-、Cl^-等的存在显著降低了TiO₂光催化剂的活性。实验结果有助于抗生素制药工业废水的光催化处理研究。     

Microwave discharge electrodeless lamps (MDEL). III. A novel tungsten-triggered MDEL device emitting VUV and UVC radiation for use in wastewater treatment.

Exposure to low doses of the xenoestrogen bisphenol A (BPA) and to the hormonal 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide, an environmental endocrine disruptor, can have serious health consequences such as the induction of mammary gland ductal hyperplasias and carcinoma (LaChapelle et al., Reprod. Toxicol., 2007, 23, 20; Murray et al., Reprod. Toxicol., 2007, 23, 383). To the extent that these toxins are present in wastewaters (Donald et al., Sci. Total Environ. 1999, 231, 173; Brotons et al., Environ. Health Perspect. 1994, 103, 608; Olea et al., Environ. Health Perspect. 1996, 104, 298; Biles et al., J. Agric. Food Chem. 1997, 45, 3541; Markey et al., J. Steroid Biochem. Mol. Biol., 2003, 83, 235), we examined their oxidative destruction in aqueous media by a novel light source. A tungsten-triggered microwave discharge electrodeless lamp (W-MDEL) was fabricated for possible use in wastewater treatment using vacuum UV-transparent quartz in which a tungsten trigger, also embedded in quartz, was attached to the MDEL to aid in the self-ignition of the lamp on irradiation at low microwave power levels. The quantity of mercury gas in the W-MDEL was optimized by monitoring the continuous radiation and peak intensities of the emitted light in the vacuum UV (VUV) and UVC regions. The usefulness of the W-MDEL device was assessed through the degradation of 2,4-D and BPA in air-equilibrated aqueous media and in oxygen-saturated aqueous media. Enhanced degradation of these two xenoestrogenic toxins was achieved by increasing the number of W-MDEL devices while keeping constant the microwave radiation feeding each W-MDEL lamp. This novel lamp provides an additional light source in the photooxidation of environmental contaminants without the need for a metal-oxide photocatalyst. Under our conditions, process dynamics using the W-MDEL light source are greater than with the more conventional photochemical methods that employ low-pressure Hg arc electrode lamps in synthetic quartz to degrade these two toxic contaminants.     

丁草胺在不同类型水中的光化学降解

研究了除草剂丁草胺在氙灯、高压汞灯光照下的光解动态。结果表明,丁草胺在氙灯光照作用下,其光解速率为纯水>河水>塘水>稻田水;丁草胺在氙灯光源下的光解速度比高压汞灯下低;其光解率与浓度(剂量)呈反相关;充N₂脱O₂使丁草胺的光解速度减缓。     

百菌清(chlorothalonil)在水中的光化学降解

研究了光源种类、溶液pH、水温和表面活性剂对百菌清光解的影响.结果表明,百菌清水溶液在高压汞灯、紫外灯和太阳光照射下的光解半衰期分别为22.4、82.5和123.8 min;在太阳光和高压汞灯照射下,百菌清在碱性溶液中比中性和酸性溶液中光解快;随着水温的升高,百菌清光解速率加快,水温平均每升高10 ℃,光解速率大约增大1倍.表面活性剂十二烷基磺酸钠、Tween 60和Span 20对百菌清的光解表现出显著的光敏化效应,十六烷基三甲基溴化铵对百菌清光解有强烈的光猝灭效应.     

Effect of broad-band ultraviolet and visible radiation on hydrogen peroxide formation by cultured rose cells

Broad-band radiation from a high-pressure Hg-vapor lamp, including ultraviolet wavelengths from 290 to 400 nm, blue, green and red wavelengths, did not induce the synthesis of H₂O₂ in cultured rose cells. This was in contrast to the effects of shortwave (254 nm) ultraviolet radiation, even though, like shortwave ultraviolet radiation, the UV-B component of the broadband radiation induced a striking K⁺ efflux from the cells, and this efflux has been associated with H₂O₂ synthesis in a previous report. The UV-A and visible wavelengths were shown to inhibit the synthesis of H₂O₂. This effect was associated with inhibition of peroxidase, an enzyme reported to be involved in the synthesis of H₂O₂ in cell walls. UV-B radiation inhibited the alternate pathway for mitochondrial electron transport, but there was no evidence that this effect contributed to the inhibition of H₂O₂ synthesis in cells treated with broad-band radiation.     

Mutation of Chinese hamster cells by near-UV activation of promutagens

A tissue-culture assay for mutagenesis and cytotoxicity incorporating near ultraviolet (NUV) light activation of polyaromatic hydrocarbons (PAH) has been developed. Cultures of Chinese hamster cells (line CHO) growing in suspension culture were inoculated with benzo[a]pyrene (B[a]P), 7,12-dimethylbenzanthracene (DMBA) or shale-oil retort-water and exposed to light from a high-pressure mercury lamp fitted with a Corning NUV bandpass filter. This light source both permitted activation of PAH and the shale-oil water and preculded detectable damage to DNA. Neither the PAH nor the NUV alone had any effect on cell survival or mutation frequencies but the chemicals plus NUV were extremely effective in producing mutations to 6-thioguanine resistance (hgprt gene).     

Thin-layer chromatographic method for the quantitative analysis of nalidixic acid in human plasma

A sensitive and highly selective thin-layer chromatographic method for determining plasma levels of nalidixic acid is presented. Plasma (50 μl) was acidified with 50 μl 1 M orthophosphoric acid and extracted with 100 μl toluene. A 40-μl aliquot of the extract was spotted onto the thin-layer plate with the aid of a Desaga Autospotter and, after irrigation, the nalidixic acid on the plate was converted into a fluorescent compound by exposing the plates to hydrogen chloride gas for 10 min and then to strong ultraviolet radiation from a mercury lamp for 10 min. The fluorescence was measured quantitatively using a spectrofluorimeter equipped with a thin-layer chromatogram scanning attachment.     

Mutagenicity of the reaction products of carbazole in the presence of nitrogen dioxide and nitrocarbazole

The mutagenicity of the photochemical reaction products of carbazole in the presence of nitrogen dioxide (NO2) and nitrocarbazole was investigated using a high-pressure mercury lamp (100 W). Samples extracted from the photochemical reaction products of carbazole with NO2 were more mutagenic than those of acridine and phenazine with NO2 for Salmonella typhimurium strain TA98 in the absence of S9 mix with a trend toward detoxification in the presence of the metabolic system. The mutagenicity of the photochemical reaction products of carbazole with NO2 were higher than those of the reaction products of carbazole with a mixture of NO2 and sulfur dioxide (SO2) and no irradiation. Mononitro- and dinitro-carbazole in the samples extracted from the reaction products were analyzed by mass spectrometry. It was suggested that mononitrocarbazole, which seemed to be weakly mutagenic, and dinitrocarbazole were readily formed by the reaction of carbazole with NO2, and that the other high-potency mutagens were formed by the photochemical reaction of carbazole with NO2 with irradiation by light.     

Photomodification of blood by laser and ultraviolet radiation: a comparative study

The efficiency of in vivo blood irradiation by a laser light source (λ = 632.8 and 670 nm) and a mercury lamp (UV light, λ = 254 nm) was compared. Absorption spectra, gas content, oxyhemoglobin content, hemoglobin oxygen saturation, concentrations of lactate and glucose were studied for both irradiated and control samples. Hemoglobin was assumed to be the primary photoacceptor of light radiation for the indicated wavelengths. No substantial differences have been found between the effects of laser and non-laser irradiation. We conclude that the biological impact of the procedure is related to photoinduced changes in hemoglobin oxygen saturation.     

Flow cytometry of Escherichia coli for process monitoring

A laser flow cytometer was used to study different Escherichia coli populations under various cultivation conditions. A host strain E. coli 5K was analyzed for cell size, protein and DNA-content during continuous cultivation. Also, a recombinant E. coli 5K(pHM12) strain (used for the intracellular production of penicillin-G acylase) was studied in regard to gene expression using different cytometric techniques. An argon ion laser (30 mW) and a 100 W high-pressure mercury lamp were used as light source in the cytometer. A new fluorogenic staining technique for intracellular penicillin-G acylase is described.Recombinant E. coli temperature sensitive cells were analyzed for intracellular fusion protein production due to temperature induction.