Light Fluorescent Lamps Research Articles

Responses of Aspergillus oryzae to Stimuli from Near-UV Light Irradiation in the Presence or Absence of Titanium Dioxide

The responses of Aspergillus oryzae to the stimuli from near-UV irradiation were investigated by using a black light fluorescent lamp in the presence or absence of TiO2 particles. Light irradiation at an intensity of 6 W/m2 strongly inhibited the growth of germinated pellets of A. oryzae. This growth inhibition was weakened by TiO2 particles (0.05 g/l), especially in the initial growth phase, in which the expression level of catalase gene (catB) was approximately three times higher than that in the absence of TiO2 particles. However, the initial induction of catB expression by H2O2 pretreatment did not restore the growth under the black light irradiation. The weakening of growth inhibition is thought to result from alternative physiological responses of A. oryzae against stimulus by photo-excited TiO2.

Green light stimulates somatic growth in the barfin flounder Verasper moseri

We examined the effects of different light wavelengths-blue, green, and red-on the somatic growth of the barfin flounder Verasper moseri, a flatfish. The light sources used were fluorescent lamps and a combination of daylight and fluorescent lamps that produced ambient light. These light sources were filtered using blue, green, or red filters. During the experiments, the fish were reared in indoor tanks with running seawater of natural temperature and fed with commercial pellets twice daily until satiety. The tanks were white in color. Fish were exposed to constant light emitted from the fluorescent lamps (9:15, light:dark; 08:00-17:00, light) for 14 weeks from October or September to January or to ambient light with a 14-week natural photoperiod from September to December. The wavelengths that were filtered from the fluorescent lamp light modified the growth of the fish, i.e., fish reared under green or blue light exhibited a greater total length (TL; P<0.01) and body weight (BW; P<0.01) than those reared under red light. In contrast, in the case of fish exposed to filtered ambient light, fish reared under green light exhibited a greater TL (P<0.01) and BW (P<0.01) than fish exposed to other wavelengths-blue-, red-, and nonfiltered ambient light. Our results indicate that flounder growth was modified by certain wavelengths, namely, green and red light, which had growth-stimulating and growth-inhibiting effects, respectively.

Novel Light-Activated Antimicrobial Coatings Are Effective Against Surface-Deposited Staphylococcus aureus

Aerosols constitute a major route of transmission for a wide range of infectious diseases in the hospital setting. The aim of this study was to determine the survival of Staphylococcus aureus on a light-activated antimicrobial coating. S. aureus suspended in phosphate-buffered saline (PBS), saliva, or horse serum was sprayed onto cellulose acetate coatings containing toluidine blue O and rose bengal and the survival of the organism on these surfaces was determined following 6 h of exposure to a 28-W domestic fluorescent lamp (light intensity = 3700 +/- 20 lux). Kills ranging from 78.9% (in horse serum) to 99.8% (in PBS) were obtained when the bacterial density on the coatings was approximately 10(5) colony-forming units/m(2). The results of this study have shown that a coating containing toluidine blue and rose bengal can achieve significant kills of S. aureus when illuminated by a domestic light source. Light-activated coatings could provide a simple, low-cost means of reducing the microbial load in hospitals and other facilities.

Application of photocatalysis as a post treatment method of a heterotrophic–autotrophic denitrification reactor effluent

The aim of this study is the application of photocatalysis as an effective post treatment scheme for the removal of the organic matter and bacteria released by an innovative biological denitrification process referred to as heterotrophic–autotrophic denitrification, which combines heterotrophic and autotrophic denitrification processes. Photocatalytic treatment was applied using TiO 2 as a photocatalyst in the loading range of 0.25–2.00 g l −1 for irradiation periods up to 60 min using a black light fluorescent lamp with an intensity of I 0 = 1309 μW cm −2. The photocatalytic inactivation data were modelled to pseudo first order kinetics as well as by the areal rates to evaluate the photocatalyst loading effect. Chlorination was used as a final disinfection step to attain an overall inactivation of total coliforms as well as to the formation of very low level of trihalomethanes.

Fully sealed carbon nanotube flat-panel light source and its application as thin film transistor–liquid-crystal display backlight

The authors investigated a full sealed flat-panel light source, which is based on a triode structure with a metal mesh gate electrode and uses a carbon nanotube cold cathode. It has a flat surface luminance distribution with good uniformity, a stable luminance of 12000cd∕m2, and a luminous efficiency that was measured to be 14.5lm∕W. It also shows a high color rendering index of 88 and a wide optical emission spectrum. Further, its application as thin film transistor–liquid-crystal display (TFT-LCD) backlight was demonstrated and the resulted performance of the TFT-LCD display was studied and compared to the commercial TFT-LCD products, which use the cold-cathode fluorescent lamp backlight and light emitting diode backlight. It is shown that the light transmission ratio in the TFT-LCD module using our light source is ∼8%, as compared to ∼4% of the commercial products. With this and the very high luminance, our light source is very useful to the situation, in which the TFT-LCD screen is employed to work under outdoor sunshine conditions.

Comparison of methodologies for conidia production by Alternaria alternata from citrus.

Conidia production is a problem in the study of Alternaria alternata from citrus. Thus, this study aimed to compare existing methodologies for conidial production of A. alternata isolated from Ponkan tangerine (2 isolates), Cravo lemon (1 isolate), Pêra orange (2 isolates) and Murcott tangor (1 isolate). The methodologies used were conidia production with 12 and 24 hours under white fluorescent light, evaluation with 24 and 48 hours after applying fungal mycelium stress technique, cold stress followed by injury of mycelium and evaluation with 24 hours, using healthy vegetable tissue and the use of black fluorescent near ultraviolet (NUV) lamp. Satisfactory result was obtained with A. alternata isolate from Murcott tangor, with the production of 2.8 × 105 conidia mL-1, when fungal mycelium was stressed (Petri dish with 66.66% of fungi growth) and subsequently 24 h of growth. The use of white light (24 h) and black fluorescent NUV lamp also induced expressive conidia production by one isolate of Ponkan tangerine, which produced 17.2 × 105 and 10.1 × 105conidia mL-1 and another of Murcott tangor, which produced 13.9 × 105 and 10.1 × 105 conidia mL-1, respectively. The remaining methodologies analyzed in this study were not able to induce conidia production in satisfactory quantity. The use of both mycelium stress technique and white light (24 h) and black fluorescent NUV lamp allowed the production of enough quantities of conidia to be used in vitro (detection of fungitoxic substances) and in vivo (pathogenicity test) assays, respectively.

Gas-Phase Photocatalytic Oxidation of Ethylene with TiO2-Coated Packaging Film for Horticultural Products

Titanium dioxide (TiO2)-coated food packaging film prepared by using colloidal suspension was examined for its catalytic properties towards the photodegradation of ethylene, a primary contaminant in the package atmosphere. The TiO2 suspensions were coated onto the surface of oriented-polypropylene film (OPP) using a bar coater and dried in air; the resulting film has a milky whitish appearance. The ethylene decomposition rate increased as the TiO2 particle size was decreased. Results showed that TiO2 nanoparticles offered a larger surface area for adsorption and decomposition of ethylene and higher UV light absorption than TiO2 microparticles. Using TiO2 nanoparticles, ethylene decomposition increased as the TiO2 concentration increased from 0.1% to 10%. A Langmuir-Hinshelwood expression was used to correlate the entire set of rate data. The relative higher photocatalytic activity was obtained with the 10% TiO2 nanoparticle coated film. The application of the 10% TiO2 nanoparticle coated film on photodecomposition of ethylene in the packaging headspace of tomato fruits was also tested. The reduction of ethylene in the package atmosphere achieved by TiO2-coated film was 88% ±6% using black light lamps, while 76% ±10% reduction was achieved using fluorescent light lamps. The results suggested that the TiO2-coated film can be used as an ethylene scavenger packaging for horticultural products.

Night Break Treatment Using Different Light Sources Promotes or Delays Growth and Flowering of Eustoma grandiflorum (Raf.) Shinn.

Night break treatment was applied to Eustoma grandiflorum ‘Neilpeach Neo’ using different light sources to investigate growth and flowering responses. The seedlings were grown in a greenhouse and treated with night break treatment using a far-red fluorescent lamp, a plant growth fluorescent lamp, a daylight-type fluorescent lamp or an incandescent lamp, or were grown under non-treated conditions (control). Photosynthetic photon flux density (PPFD) at the top of the plant was 5 μmol·m−2·s−1 under each light source. The red (660 ± 30 nm): far-red (730 ± 30 nm) ratio of the light sources was 0.01, 0.43, 5.00, and 0.65, respectively. The time from planting to flower budding was 46 days for plants grown under a far-red light fluorescent lamp, compared with 66 days in the control. The incandescent lamp and plant growth fluorescent lamp also reduced the time to flower budding; however, the daylight-type fluorescent lamp delayed flower budding by 4 days compared with the control. The light source regimes had little or no effect on the time to flowering after flower budding. The far-red fluorescent lamp, incandescent lamp and plant growth fluorescent lamp reduced the number of nodes on the main stem at the anthesis of the first floret, while the daylight-type fluorescent lamp increased the number of nodes. The far-red fluorescent lamp and incandescent lamp promoted internode elongation, while the daylight-type fluorescent lamp reduced internode length. Moreover, a red fluorescent lamp with a R: FR ratio of 105 delayed flower budding and flowering, and increased the number of nodes of the plants as compared with the control, regardless of the long day lengths in July and August. Thus, it is considered that the growth and flowering time of Eustoma grandiflorum can be controlled by long-day treatment carried out with the proper type of light source.

Treatment technologies for mercury in soil, waste, and water

AbstractMercury occurs naturally in the environment and can be found in elemental (metallic), inorganic, and organic forms. Modern uses for mercury include chemical manufacturing, thermometers, and lighting (mercury vapor and fluorescent lamps). The chemical and allied products industry group is responsible for the largest quantity of mercury used in the United States. Mercury, particularly the organic methylmercury form, is a potent neurotoxin capable of impairing neurological development in fetuses and young children and of damaging the central nervous system of adults. Mercury regulations span multiple federal and state environmental statutes, as well as multiple agency jurisdictions. In August 2007, the U.S. Environmental Protection Agency's (US EPA's) Office of Superfund Remediation and Technology Innovation (OSRTI) published a report titled “Treatment Technologies for Mercury in Soil, Waste, and Water.“ The report identifies eight treatment technologies and 57 projects, 50 of which provide performance data. This information can help managers at sites with mercury‐contaminated media and generators of mercury‐contaminated waste and wastewater to identify proven and effective mercury treatment technologies; screen technologies based on application‐specific goals, characteristics, and costs; and apply experiences from sites with similar treatment challenges. This article provides a synopsis of the US EPA report, which is available at http://clu‐in.org/542R07003. © 2007 Wiley Periodicals, Inc.*This article is a U.S. Government work and, as such, is in the public domain of the United States of America.

Effects of low or medium-pressure UV irradiation on the release of intracellular microcystin

UV irradiation could be an alternative growth inhibition treatment against toxic Microcystis blooms in lakes. This study examined the effect of UV irradiation on the release of toxic intracellular microcystin. Conventional algicidal treatment (e.g. copper sulfate) was known to cause rapid release of intracellular microcystin and additional problems, but no studies have examined the case of UV treatment. A pure culture of Microcystis aeruginosa PCC 7806 was exposed to monochromatic low-pressure or polychromatic medium-pressure UV lamps. Irradiated pure culture suspension was subsequently incubated for 14 days under white light fluorescent lamps. During incubation, profiles of the number of cells, intracellular and extracelluar microcystin concentration were determined. After the UV exposure, the number of cells gradually diminished; the net log cell reduction after 6 days of incubation was 1.6 log or 2.0 log for 600 mJ/cm 2 of LP or MP UV irradiation, respectively. There were three findings for UV irradiation effects on the release of intracellular microcystin. First, because UV exposure can inhibit increases in the number of cells for about 6 days, it inhibited the increase of microcystin concentrations in water. Second, intracellular microcystin was gradually released into the surrounding water through a gradual reduction in the number of cells, preventing a rapid increase of microcystin concentration in water. Microcystin concentration in water was not significantly higher in UV-irradiated samples than non-UV-irradiated sample. Third, UV irradiation was able to degrade intracellular microcystin; it was reduced from 24.6 to 7.06 or 7.16 fg/cell by 600 mJ/cm 2 of LP or MP UV irradiation, respectively. This contributed to reduce increases in microcystin concentrations in water. UV treatment can inhibit Microcystis growth and reduce intracellular microcystin content without rapid release of intracellular microcystin.

Sterilization effects of a TiO2 photocatalytic film against aStreptococcus mutans culture

Streptococcus mutans is one of the more significant pathogens involved in the development of dental caries in humans. The purpose of this research was to design a TiO2-coated dental instrument and to determine the bactericidal effects of the instrument onS. mutants. TiO2 photocatalytic films were prepared by the low-pressure metal-organic chemical vapor deposition (LPMOCVD) method using titanium tetraisopropoxide (TTIP) as precursor. The photocatalytic reaction was carried out on a TiO2-coated pyrex petri dish with an ultraviolet (UV) light emitting diode (LED) illuminator or a fluorescent lamp light source. Our data indicates that the relative survival ratio ofS. mutans when plated onto TiO2 photocatalytic films and under exposure to UV-A light for 15 min was 0.01%. In addition, a fluorescent lamp light source also had bactericidal effects on theS. mutans plated TiO2 photocatalytic films. These results indicate that TiO2-coated dental materials or devices may be useful in dental treatments for the prevention of carious or enamel demineralization.

On the mechanism of boron-subphthalocyanine chloride formation

A mechanistic study of chloroboron subphthalocyanine (SubPc) formation from phthalonitrile and BCl 3 in aromatic solvents such as p-xylene or toluene suggests that rearrangement of the initial phthalonitrile- BCl 3 adduct produces (1 Z )-3-chloro-N-(dichloroboryl)-1 H -isoindol-1-imine 3, following rearrangement of the initial phthalonitrile- BCl 3 adduct. From three molecules of (1 Z )-3-chloro-N-(dichloroboryl)-1 H -isoindol-1-imine 3, by successive addition, the dichlorosubstituted macrocycle 7 is formed. Quantum-chemical computation shows that the postulated elementary reaction steps leading up to the formation of the SubPc-precursor macrocycle are indeed exothermic, or at least kinetically allowed. The formation of the SubPc is concluded by the elimination of chlorine which is probably catalyzed by BCl 3 in a concerted process which might be represented as: dichlorosubstituted macrocycle 7 + BCl 3 → SubPc · Cl + + BCl 4- → SubPc + Cl 2 + BCl 3. The chlorine formed may be photolytically affected if the reaction is carried out under ordinary laboratory lighting (fluorescent lamps), giving rise to a free-radical chain reaction involving the solvent. Alternatively, molecular chlorine may react with aromatic solvents such as toluene and p-xylene in a Friedel-Crafts-type reaction catalyzed by BCl 3. In this way, such solvents which are reactive in both ways can protect the reactant phthalonitrile, the reaction intermediates, and the product SubPc from degradation by chlorination.

Effects of low- or medium-pressure ultraviolet lamp irradiation on Microcystis aeruginosa and Anabaena variabilis

A pure culture of Microcystis aeruginosa or Anabaena variabilis, the representatives of water blooming algae, was exposed to low-pressure (LP) or medium-pressure (MP) UV lamps. Irradiated pure culture suspension was subsequently incubated for 7 d under white light fluorescent lamps. During incubation, profiles of the number of cells, DNA damage and photosynthetic activity were determined. When UV fluence was 600 mJ/cm 2, M. aeruginosa cell numbers decreased throughout the 7-d incubation period, to produce 1.5 log reduction (LP) or 1.2 log reduction (MP) compared with control. The amount of DNA damage was 2.02×10 −4 ESS/base (LP) and 3.42×10 −4 ESS/base (MP) just after UV irradiation, which became 0.05×10 −4 ESS/base and 0.23×10 −4 ESS/base, respectively, after 3 d incubation. However, cell number kept decreasing, even after DNA repair. Photosynthetic activity decreased by 1.5 log within 1 d (LP) or 3 d (MP). Thus, reduction in photosynthetic activity could contribute to the reduction in M. aeruginosa cell numbers. A. variabilis cell numbers reduced by 2.3 log (LP) or 2.2 log (MP) during the 7-d incubation period; however, after DNA damage repair, cell number began to increase. The amount of DNA damage was 6.07×10 −4 ESS/base (LP) and 4.48×10 −4 ESS/base (MP) just after UV irradiation, which became 0.23×10 −4 ESS/base and 0.40×10 −4 ESS/base, respectively, after 3 d incubation. No reduction was observed in photosynthetic activity/cell. Therefore, DNA damage is the main contributor of the reduction in cell number of A. variabilis.

Copper-aided photosterilization of microbial cells on TiO 2 film under irradiation from a white light fluorescent lamp

The copper-aided photosterilization of Escherichia coli was examined on TiO 2 thin films under a lighting condition with less UV rays from a white light fluorescent lamp. It was found that the coexistence of Cu 2+ and H 2O 2 in liquid phase exerted the synergistic effect on killing E. coli cells though these chemical species were individually at nontoxic levels to the cells (less than 10 mmol/m 3). At an incident light intensity of I 0 = 28 W/m 2, the addition of Cu 2+ (10 mmol/m 3) to liquid phase on TiO 2 film gave the apparent deactivation rate constant of k′ = 12 × 10 −2 min −1, the value of which was about 5 times as large as that on TiO 2 film in the absence of Cu 2+. This result suggested that in the liquid phase, Cu 2+ was reduced to Cu + by receiving electron from photo-excited TiO 2, and then Cu + reacted with photocatalysis-derived H 2O 2 to produce OH via Fenton-type reaction. The deactivation tests were also examined using a modified film preparation made from copper-incorporated TiO 2. On this film, the k′ value was 23 × 10 −2 min −1 at I 0 = 28 W/m 2, which was respectively about two and nine times as large as those on the original TiO 2 film with and without Cu 2+ addition (10 mmol/m 3). The enhancement of biocidal activity on the modified TiO 2 film was considered to arise from promoted OH formation by the aid of copper component anchored in TiO 2 solid phase.

Large‐field color matching functions

AbstractColor‐matching functions (CMFs) were derived with the Maxwell method for 10 subjects using two field conditions: (1) horizontally bisected circular 10° and (2) vertically bisected rectangular 102° (wide) × 50° (high). The primary set was composed of 453–533–601 nm components with a mean full‐width at half maximum of 18.3 nm; the reference field was illuminated with daylight fluorescent lamplight. Field size had a significant effect on the shape of the resulting CMFs. Under the large‐field conditions subjects were less sensitive to shorter wavelengths as characterized with the b̄ function and had higher sensitivities to the longer wavelengths as characterized with the r̄ function. © 2005 Wiley Periodicals, Inc. Col Res Appl, 31, 18–29, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20170

Phosphor Converted Three-Band White LED

The development of wide band gap III-V nitride compound semiconductors has led to the commercial production of high-efficiency LEDs. The recent advent of blue InGaN technology has made it possible to produce a conventional white LED in which white light is obtained by coating a Y3Al5O12:Ce (or Sr3SiO5:Eu) phosphor onto a blue LED chip. In this device, known as a two-band white LED, white light is generated by additive color mixing of the blue light emitted by the blue LED and the yellow light emitted by the Y3Al5O12:Ce phosphor. The development of a white LED is important because it opens the way for LED applications such as light bulbs and fluorescent lamps with high durability and low energy consumption. However, the spectral composition of the light produced by the conventional two-band white LED differs from that of natural white light, particularly in the red region. The color properties of conventional two-band white LEDs can potentially be improved by adding another component to create a white LED based on three emission bands (a three-band white LED). Full-color fluorescent display devices have been developed by using a combination of ZnS:Ag (blue), ZnS:Cu,Al (green), and ZnCdS:Ag (red) phosphors excited by a nearUV LED. In addition, a white light source has been obtained by intergrating ZnS:Ag (blue), ZnS:Cu,Al (green), and Y2O2S:Eu (red) phosphors, and a UV-LED (350 nm). White light has also been achieved by combining a blue LED (460 nm) with SrGa2S4:Eu (green) and SrS:Eu (red) phosphors. Previously, we constructed a three-band white LED by combining a blue LED (465 nm) with SrGa2S4:Eu (green) and ZnCdS:Ag,Cl (red) phosphors. In the present work, we investigated the optical properties of a white LED which was obtained by using a blue LED (465 nm) in conjunction with SrGa2S4:Eu (green) and SrY2S4:Eu (red) phosphors. The SrY2S4:Eu phosphor was chosen over the ZnCdS:Ag,Cl phosphor used in our previous work in order to improve the red color characteristics of the white LED.

Visually matching daylight fluorescent lamplight with two primary sets

AbstractThornton reported discrepancies in chromaticity and power content in Maxwell‐method visual matches when using different primary sets. He found particularly large chromaticity differences when a broadband white light was matched with what he refers to as an antiprime (AP) primary set [blue‐green, yellow, deep red, as, for example 497–579‐653 nm, mean full‐width half‐maximum (FWHM) = 15.6 nm] and comparatively smaller chromaticity differences with a prime‐color (PC) primary set (blue‐violet, green, orange‐red, as, for example, 452–533‐607 nm, mean FWHM = 15.6 nm). In related work, Ábrahám et al. found similar chromaticity discrepancies when subjects reported a visual match, partially attributing the errors to age‐related changes in the specular transmittance of the lens. This present study was carried out to explore these findings and to investigate individual differences in color matching. Thirty‐nine subjects made two matches in a horizontally bisected 10° field. The bottom field was illuminated with daylight fluorescent lamplight and the top field was illuminated with one of two primary sets that were selected to be similar to those used by Thornton and Ábrahám et al.: (1) PC = 453–533‐619 nm with a mean FWHM of 18.3 nm and (2) AP = 493–581‐657 nm with a mean FWHM of 23.7 nm. Statistical data screening revealed two outliers that were removed from further analysis. The PC primary set required 5% less radiant power per unit area to match the daylight fluorescent reference and the AP set required 117% more. Thirty‐six of the 37 matches with the PC primary set were within a 10‐step MacAdam ellipse that was centered at the daylight fluorescent reference. In contrast, just 2 of the matches with the AP set were within a 10‐step ellipse, and 24 of the matches were outside of a 20‐step ellipse. These trends are similar to those reported by Thornton and later by Ábrahám et al. The primary set and the interaction between primary set and age were statistically significant factors. Gender and subject knowledge were not significant. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 428–437, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20059

光触媒を用いた淡水性藻類の増殖抑制に関する研究

The inhibition of freshwater algal growth was investigated using powdered TiO2 as a photocatalyst under artificial sunlight irradiation with a combination of fluorescent lamp and black light in order to develop a new method of water quality improvement in lakes or reservoirs using natural energy. The growth of Microcystis aeruginosa, Anabaena solitalia and Coelastrum astroideum was effectively inhibited by using powdered TiO2 photocatalyst at a concentration of 100mg·l-1, whereas that of Fragilaria capucina wasn't.

New Color Filter for Light-Emitting Diode Back Light

In this report, we propose new color filter design applied to light-emitting diodes (LEDs) back-light unit. Our new system with LED back light and new color filter (CF) successfully realizes the color gamut with over 100% against that of the National Television System Committee (NTSC). The brightness of white is 1.5 times that for the system with new CF for cold-cathode fluorescent lamp (CCFL) and CCFL back light. This system, at the same time, is highly promising for future liquid crystal displays (LCDs) since it can meet both high image qualities and eco-friendly properties of such devices.

磁性材料・半導体 化合物半導体白色ＬＥＤ照明技術による“２１世紀のあかり”

The technology of white LEDs which is connected with the InxGa1-xN blue LED coated with a YAG : Ce phosphor, has improved the white LED efficiencies to approximately 30 lm/W. We have reported a maximum luminous efficacy of about 40 lm/W using 700 LEDs lighting source at electric power of 5 W. It has been expected that extremely high-brightness white LEDs can significantly replace standard incandescent bulbs. We have also demonstrated an energy saving type street lamp linked with a photovoltaic solar cell using a 10 Cd-class white LEDs array lighting source. An alternative method of making a color conversion white LEDs is provided to produce a true white which can be achieved using three colors from red, green, and blue phosphors excited by ultraviolet (UV) LEDs. In the future, as the efficiency of blue and UV LEDs will be improved, the white LED lamps may replace conventional light bulbs or fluorescent lamps in many applications.