High Intensity Ultraviolet Light Research Articles

An optical fiber sensor based on cladding photoluminescence for high power microwave plasma ultraviolet lamps used in water treatment

Low-pressure mercury lamps are commonly used for germicidal applications such as water and wastewater sterilisation. The germicidal effect is due to the emission of light at 254 nm, which leads to the destruction of most waterborne bacteria. The Microwave plasma ultraviolet lamp (MPUVL) is a new technology for generating a high intensity ultraviolet (UV) light. A Fluorescent optical fiber based sensor is presented which is used for monitoring the output of a high power microwave UV light source and its control. This sensor is a fiber which has had its cladding removed and been coated with a phosphor doped polymer.

Low-pressure microwave plasma ultraviolet lamp for water purificationand ozone applications

Low-pressure mercury lamps are commonly used for germicidalapplications. The germicidal effect is due to the emission of light at 254 nm,which leads to the destruction of the most waterborne bacteria and viruses.The microwave plasma ultraviolet (UV) lamp (MPUVL) is a new technology forgenerating a high-intensity UV light and that can be also controlled tooperate at 185 nm; irradiation is in air at this wavelength produces ozone.The microwave power is injected into a resonant cavity and thesurface wave excitation takes place within the cavity through that part of thedischarge tube (fused silica) protruding inside it. The MPUVL has manyadvantages over conventional lamps, which are limited to an output power inthe region of 30 W m-1, while MPUVL can deliver any amount of power perunit length and the tube can be of any shape, length or diameter. This paperdescribes the design of the MPUVL and compares its efficiency with that ofconventional lamps through spectral analysis. Other results, which include theeffects of temperature and different power inputs, are also discussed.

High-Intensity Low-pressure Electrodeless UV Lamps for The Sewage Effluent Disinfection System

High-Intensity Low-pressure Electrodeless UV Lamps for The Sewage Effluent Disinfection SystemRecently, ultraviolet (UV) radiation has been applied as a disinfection method on the sewage treatment works. A high-intensity and high-power UV light source is required in the field of bacilli sterilization. Using RF frequency power circuit technology and optimizing UV lamp shape, we have made it possible to input power, 500W, to a 500mm-length luminescence lamp. Moreover, a 30% maximum rate of...Author(s)Shinji KobayashiAkinori HatanoYoshio NakayamaSourceProceedings of the Water Environment FederationSubjectSession 62 - Facility Operations I: UV DisinfectionDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2000ISSN1938-6478SICI1938-6478(20000101)2000:8L.162;1-DOI10.2175/193864700784546873Volume / Issue2000 / 8Content sourceWEFTECFirst / last page(s)162 - 168Copyright2000Word count115

Quantitative analysis of Z-2-[4-(4-chloro-1,2-diphenyl-but-1-enyl)phenoxy]ethanol in human plasma using high-performance liquid chromatography

A highly sensitive and precise high-performance liquid chromatography (HPLC) assay was developed and validated for the quantitation of Z-2-[4-(4-chloro-1,2-diphenyl-but-1-enyl) phenoxy]ethanol (FC-1271a) in human plasma. Plasma samples (1.0 ml) containing FC-1271a and internal standard (toremifene citrate; Fareston ®) were extracted using a 2% 1-butanol, 98% hexane solution with an extraction efficiency of >97%. Samples were reconstituted in methanol, irradiated with high intensity ultraviolet light (254 nm) for 1 min, and injected onto a C 18 reverse phase column. Samples were eluted isocratically at a flow-rate of 0.5 ml/min with a mobile phase consisting of 6.5% water and 0.5% triethylamine in methanol. The fluorescence of photochemically activated compounds was detected using a fluorometer set at an excitation wavelength of 266 nm and emission wavelength of 370 nm. Under these assay conditions, standard calibration curves were linear through a concentration range of 10–400 ng/ml. In summary, we have developed and validated an HPLC assay to quantitate FC-1271a in human plasma.

Water-soluble organic nitrogen in atmospheric aerosol: a comparison of UV and persulfate oxidation methods

Two well established methods that are widely applied in the determination of marine dissolved organic nitrogen (DON) have been investigated in their application to the determination of rainwater DON and the water-soluble organic nitrogen component of atmospheric aerosol. Empirical observation highlighted some difficulties in the analysis of DON in these non-marine matrices, so some practical suggestions for the extension of the oxidative methods to atmospheric samples are proposed. Ten rain samples, 20 aqueous aerosol extracts, and a suite of commercially obtained organic nitrogen compounds were both chemically oxidised by persulfate and oxidised by exposure to high-intensity ultraviolet light. The total dissolved nitrogen concentration of the rains in this study ranged from 4 to 35 μM nitrogen. The aerosol extracts were diluted to a pre-oxidation concentration range of 12–65 μM N for oxidation and analysis. Both UV and persulfate methods require the aqueous extract of the aerosol organic nitrogen to be diluted approximately to rainwater concentrations for optimal oxidation efficiency, since sub-optimal recoveries and high analytical variability arise at high concentration. Some potential causes of analytical interference at higher concentration are discussed. This study shows that total dissolved nitrogen results obtained by the two methods are linearly correlated (with an R 2 of 0.87 for 30 samples) over the full range of natural rainwater concentrations, but results obtained using the persulfate oxidation are about 30% lower than those obtained by photo-oxidation.

Reconfigurable optical properties in InGaN/GaN quantum wells

Reconfigurable optical properties were studied in InGaN/GaN multiple quantum well (MQW) structures. It was observed that a short time exposure to a high intensity ultraviolet light results in long term, but reversible changes of the optical properties of InGaN/GaN MQW samples. The photoinduced changes can be observed using an optical microscope under low intensity ultraviolet light and are visible as a high contrast pattern. The retention time at room temperature for 12 and 20 MQW samples was longer than five days and four weeks, respectively. The effect was studied at room and cryogenic temperatures.

UV fine tuning of narrow channel fused fibre wavelengthdivisionmultiplexing couplers

The wavelength response of fused fibre wavelength division multiplexers with channel spacings between 8 and 24 nm was altered by exposure to high intensity ultraviolet light. Wavelength shifts are shown to be the result of changes in the index of refraction of the glass in the fused region of the couplers, with effective index of refraction changes in the illuminated area estimated to be between 10–3 and 10–2.

Dissolved organic carbon in oligotrophic waters: experiments on sample preservation, storage and analysis

Abstract Different methods of preservation and storage of samples for analysis of abundance of dissolved organic carbon (DOC) in oligotrophic waters were evaluated and compared to shipboard measurements. DOC concentrations in samples stored frozen (−20°C) in acid-cleaned polypropylene tubes, high-density polyethylene bottles, and combusted glass ampoules, even for extended periods (up to 5 months after collection), were indistinguishable from those measured on ship at the time of collection. Addition of phosphoric acid (0.025% H 3 PO 4 final concentration in seawater) was necessary to preserve samples at 4°C. Filtration prior to storage was not necessary for the oligotrophic ocean samples analyzed in this study. Removal of dissolved inorganic carbon can be accomplished by bubbling with either high-purity nitrogen or oxygen with no effects on DOC abundance measurements. An estimate of the analytical blank was determined by injecting distilled water which was exposed to high-intensity ultraviolet light, acidified and purged with nitrogen to remove inorganic carbon. The analytical blank measured in this study was 18.7 ± 1.5 μ m C for a 100 μl injection volume. This value was applied as the minimum correction to DOC abundance measurements of seawater. Using the methods described in this paper we observed DOC concentrations of approximately 90–115 μM C for the upper 50 m of the water column at the US-JGOFS Station Aloha (22°45′N, 158°W). DOC concentrations decreased with depth to concentrations of approximately 50 μM C at 500 m and remained relatively constant at greater depths.

Treatment of contaminated water, air and soil with UV flashlamps

AbstractA new and effective method has been developed for the treatment of VOC's, PCB's and other toxic organics. Direct UV photolysis of organics is achieved with this new method with the use of high intensity ultraviolet light of a broad UV spectrum. Standard and novel UV flashlamps can be used for generation of this broad UV spectrum. The pulsing nature of such spectrum helps to increase the efficiency of destruction of toxics. The final products of this destruction process are non‐toxic simple compounds. The energy efficiency of this new process exceeds that of traditional UV aided processes with medium pressure mercury lamps. This article reviews the Direct UV Photolysis Process, gives experimental results, and provides recommendations for applications in the treatment of groundwater, wastewater, contaminated air and soil.

Intracellular diffusion, binding, and compartmentalization of the fluorescent calcium indicators indo-1 and fura-2

We studied intracellular binding and possible compartmentalization of the fluorescent Ca2+ indicators, indo-1 and fura-2, in single mammalian cardiac ventricular cells that had been loaded with indo-1 and fura-2 by exposure to the acetoxymethylester form of the indicators (indo-1/AM and fura-2/AM). Techniques similar to those used in experiments on fluorescence recovery after photobleaching (FRAP) were used. It was assumed that reversible binding in myoplasm would be evident as slowed recovery of fluorescence after photobleaching, and that irreversible binding of the indicators to immobile myoplasmic sites (or "compartmentalization" in organelles) would be evident as incomplete recovery. Through the use of a mask, one half of a cell was exposed to high-intensity ultraviolet (UV) light to bleach the indo-1 or fura-2 in only that part of the cell. Upon removal of the mask and termination of the high-intensity UV illumination, fluorescence recovered in the bleached half of the cell, indicating diffusion of indo-1 and fura-2. Mathematical modeling of the diffusional redistribution of the indicators indicated that in these cells the apparent diffusion coefficient for indo-1 is 1.57 x 10(-7) cm2 s-1 (SD 0.48 x 10(-7) cm2 s-1; n = 5 cells, 21 degrees C), and for fura-2 is 3.19 x 10(-7) cm2 s-1 (SD 1.85 x 10(-7) cm2 s-1; n = 6 cells, 21 degrees C). These values are approximately 6 and 3, respectively, times smaller than those expected for free diffusion in the myoplasm. In the bleached half of the cell the recovered level of fluorescence never reached the final level in the half not exposed to UV light. The extent of incomplete recovery was variable amongst the cells. Our analysis indicated that, under the conditions we used, approximately one-third of the intracellular dye is not diffusible in the myoplasm.

Quantitative Analysis of Toremifene Metabolites in Biological Specimens Using High-Performance Liquid Chromatography

Abstract Toremifene is a triphenylethylene derivatiye that is currently undergoing Phase I-III clinical trials for antineoplastic activity. Toremifene has also shown chemosensitizing activity in multidrug resistant cancer cells. In the present study, we developed a modified HPLC assay which allows for separation, and quantification of toremifene metabolites in biological specimens. Plasma samples containing various quantities of toremifene metabolites were spiked with an internal standard (nafoxidine), extracted with 2% butanol in hexane, and irradiated with high intensity ultraviolet light (254 nm). Aliquots of the extracted plasma components were injected onto a C18 reverse phase column and eleuted isocratically with a mobile phase of 7% water and 0.18% triethylamine in methanol. Fluorescence of toremifene metabolites, and internal standard was measured at an excitation wavelength of 266nm. The sensitivity of this assay was approximately 20 ng/mL for each metabolite. Linearity was achieved for all the c...

Irradiation of the template with high-intensity (pulse-laser) ultraviolet light results in DNA-polymerase termination events at deoxyguanosine residues

During primer elongation by Escherichia coli DNA-polymerase I large fragments on the template were irradiated with UV laser pulses at an intensity ⩾ 10 10 W m 2 . In addition to the termination events at photoproducts typical of low-intensity UV irradiation, termination is observed before deoxyguanosine residues. The effect of the UV light intensity on the ratio of termination efficiencies before dPy and dG suggests that the termination of polymerization before deoxyguanosine residues results from the formation of photoproducts yielded by two-quantum reactions. The results obtained herein, together with data published previously, imply that photomodification of dG residues is the major two-quantum reaction under the action of high-intensity UV radiation on DNA.

Quantitation of Toremifene and its Major Metabolites in Human Plasma by High-Performance Liquid Chromatography Following Fluorescent Activation

Abstract A highly sensitive reverse-phase high-performance liquid chromatography assay utilizing fluorescence activation has been developed for the quantitative analysis of the anti-estrogenic compound toremifene and its major metabolites, 4-hydroxy-toremifene and N-desmethyl-toremifene. Plasma samples containing various quantities of toremifene and its metabolites were spiked with an internal standard (nafoxidine), extracted with 2% n-butanol in hexane, and irradiated with high intensity ultraviolet light (254 nm). Aliquots of the extracted plasma components were then injected onto a C-18 reversed phase column and eluted isocratically with a mobile phase of water and triethylamine in methanol. Fluorescence of toremifene, its metabolites, and internal standard was measured at an excitation wavelength of 266 nm. -The sensitivity of this assay was 8.0, 15.0 and 5.0 ng/mL for toremifene, N-desmethyl-toremifene and 4-hydroxy-toremifene, respectively. Linearity was achieved for the concentration range of 25 to...

Characterization and photoaffinity labeling of receptor sites for the Ca2+ channel inhibitors d-cis-diltiazem, (+/-)-bepridil, desmethoxyverapamil, and (+)-PN 200-110 in skeletal muscle transverse tubule membranes.

In order to further understand the molecular nature of the voltage-sensitive Ca2+ channel in skeletal muscle, we have performed classical radioligand binding studies and photoaffinity labeling with different types of tritiated inhibitors of the Ca2+ channel. The equilibrium dissociation constants (KD) for (-)-[3H]desmethoxyverapamil, d-cis-[3H]diltiazem, and (+/-)-[3H]bepridil at their receptor sites in skeletal muscle transverse tubule membranes are: 1.5 +/- 0.5, 50 +/- 5, and 20 +/- 5 nM, respectively. Maximum binding capacities in picomoles/milligram of protein were: 70 +/- 10 for (-)-[3H]desmethoxyverapamil, 50 +/- 15 for d-cis-[3H]diltiazem, and 75 +/- 15 for (+/-)-[3H]bepridil. The kinetics of association at 10 degrees C for the three types of tritiated compounds were relatively slow (3 X 10(5) M-1 S-1 for (-)-[3H]desmethoxyverapamil, 8 X 10(3) M-1 S-1 for d-cis-[3H]diltiazem, and 4.2 X 10(5) M-1 S-1 for (+/-)-[3H]bepridil). The dissociation of (-)-[3H]desmethoxyverapamil and d-cis-[3H]diltiazem from their receptor sites was also a slow process with half-lives of dissociation of 33 and 36 min, respectively. Competition studies using the three tritiated ligands suggest that they bind to the same receptor site which appears to be in a 1:1 stoichiometry with the dihydropyridine receptor. Photoaffinity labeling with high intensity ultraviolet light in the presence of (+/-)-[3H]bepridil or d-cis[3H]diltiazem resulted in the specific covalent incorporation of radioactivity into a polypeptide of Mr 170,000 +/- 10,000. A polypeptide of Mr 170,000 was also specifically labeled in photoaffinity labeling experiments using the high affinity dihydropyridine derivative (+)-[3H]PN 200-100.

Photoaffinity labeling of insulin-sensitive hexose transporters in intact rat adipocytes. Direct evidence that latent transporters become exposed to the extracellular space in response to insulin.

Irradiation of intact rat adipocytes with high intensity ultraviolet light in the presence of 0.5 microM [3H] cytochalasin B results in the labeling of Mr 43,000 and 46,000 proteins that reside in the plasma membrane fraction. In contrast to the Mr 46,000 protein, the Mr 43,000 component is not observed in the microsome fraction and exhibits lower affinity for [3H]cytochalasin B. Photolabeling of the Mr 43,000 protein is inhibited by cytochalasin D, indicating it is not a hexose transporter component. The Mr 46,000 protein exhibits characteristics expected for the glucose transporter such that D-glucose or 3-O-methylglucose but not cytochalasin D inhibits its photolabeling with [3H] cytochalasin B. Furthermore, insulin addition to intact cells either prior to or after photoaffinity labeling of the Mr 46,000 protein causes a redistribution of this component from the low density microsomes to the plasma membrane fraction, as expected for the hexose transporter. Photolabeling of transporters in both the low density microsome and plasma membrane fractions is inhibited when intact cells are equilibrated with 50 mM ethylidene glucose prior to irradiation with [3H]cytochalasin B. Incubation of intact cells with 50 mM ethylidene glucose for 1 min at 15 degrees C leads to an intracellular concentration of only 2 mM. Under these conditions, the photoaffinity labeling in intact cells of hexose transporters that fractionate with the low density microsomes is unaffected, indicating these transporters are not exposed to the extracellular medium. In contrast, photolabeling in intact insulin-treated cells of hexose transporters that fractionate with the plasma membrane is inhibited under these incubation conditions. The results demonstrate that insulin action results in the exposure to the extracellular medium of previously sequestered hexose transporters.

Instant colour photography: chemistry and UV stabilization

An ultraviolet (UV) screening agent precursor, dinonylphenylisophthalate, applied as a component of a surface coating on instant colour positive photographic prints stabilizes the dyes that are used and prevents the fading of colour that otherwise occurs. It is believed that upon exposure to UV light the ester precursor rearrangesin situ to form substituted benzophenones, which are effective UV screening agents. Eastman Kodak instant colour prints protected by this system successfully resisted prolonged exposure to high intensity UV light. Under the same conditions, unprotected controls showed extensive fading and other changes in colour. Extension of the general technology to prevent colour fading of dyes in other applications is foreseen.

The determination of dissolved organic carbon in sea water

For most oceanographic applications, methods based on wet oxidation of the organic fraction, followed by stripping of the resulting CO 2 and measurement in the gas phase by non-dispersing infrared detectors give acceptable results. Oxidation by high-intensity ultraviolet light has advantages, particularly in ease of automation, over persulfate oxidation.

Photochemotherapy of vitiligo. Use of orally administered psoralens and a high-intensity long-wave ultraviolet light system.

A new light source that provides high-intensity ultraviolet light (UVA) (300 to 400 nm) to the entire body surface makes orally administered psoralen treatment of vitilligo with an artificial light practical. In the 26 patients studied, the degree of repigmentation with either trioxsalen (TMP) or methoxsalen (8-MOP) and high intensity UVA was at least as great as that with the same oral agents and sunlight. With artificial UVA and similar treatment conditions, the two psoralen derivatives were compared in the treatment of vitiligo; TMP stimulated repigmentation as well as 8-MOP and caused fewer side effects.

Photochemical Technique for the Elimination of Chlorinated Aromatic Interferences in the Gas-Liquid Chromatographic Analysis for Chlorinated Paraffins

A method is described for eliminating chlorinated aromatic interferences in the analysis for the more volatile chlorinated paraffins. Sample extracts are irradiated in aliphatic hydrocarbon solvents with high intensity ultraviolet light prior to detection of the chlorinated paraffin by microcoulometric gas-liquid chromatography. Chlorinated aromatic and unsaturated materials, including DDT and polychlorinated biphenyls, are selectively degraded to compounds containing little or no chlorine. Cycloaliphatic pesticides such as toxaphene, chlordane, and mirex are only partially degraded. Analysis of fish fillets fortified with 1 and 5 ppm of a chlorinated paraffin gave recoveries greater than 90%.

A hypothesis on the preferential destruction of melanized tissues

Based on existing biological data and the known amorphous semi-conductor properties of the melanins, a hypothesis to explain the preferential death of melanized cells is presented. This hypothesis suggests that melanized cell death associated with Parkinson's disease and other syndromes involving non-illuminated areas occurs as a result of non-radiative transfer of energy to and from the melanins. This mechanism is also consistent with the observation that melanized cells are preferentially killed by high intensity ultraviolet light in illuminated areas, but the melanins appear to be cytoprotective at low intensities.