WorldWideScience

Sample records for halogen light irradiation

  1. [Near infrared light irradiator using halogen lamp].

    Science.gov (United States)

    Ide, Yasuo

    2012-07-01

    The practical electric light bulb was invented by Thomas Alva Edison in 1879. Halogen lamp is the toughest and brightest electric light bulb. With light filter, it is used as a source of near infrared light. Super Lizer and Alphabeam are made as near infrared light irradiator using halogen lamp. The light emmited by Super Lizer is linear polarized near infrared light. The wave length is from 600 to 1,600 nm and strongest at about 1,000 nm. Concerning Super Lizer, there is evidence of analgesic effects and normalization of the sympathetic nervous system. Super Lizer has four types of probes. SG type is used for stellate ganglion irradiation. B type is used for narrow area irradiation. C and D types are for broad area irradiation. The output of Alphabeam is not polarized. The wave length is from 700 to 1,600 nm and the strongest length is about 1,000nm. Standard attachment is used for spot irradiation. Small attachment is used for stellate ganglion irradiation. Wide attachment is used for broad area irradiation. The effects of Alphabeam are thought to be similar to that of Super Lizer.

  2. Accuracy of LED and halogen radiometers using different light sources.

    Science.gov (United States)

    Roberts, Howard W; Vandewalle, Kraig S; Berzins, David W; Charlton, David G

    2006-01-01

    To determine the accuracy of commercially available, handheld light-emitting diode (LED) and halogen-based radiometers using LED and quartz-tungsten-halogen (QTH) curing lights with light guides of various diameters. The irradiance of an LED curing light (L.E. Demetron 1, SDS/Kerr, Orange, CA, USA) and a QTH curing light (Optilux 501, SDS/Kerr) were measured using multiple units of an LED (Demetron L.E.D. Radiometer, SDS/Kerr) and a halogen radiometer (Demetron 100, SDS/Kerr) and compared with each other and to a laboratory-grade power meter (control). Measurements were made using five light guides with distal light guide diameters of 4, 7, 8, 10, and 12.5 mm. For each light guide, five readings were made with each of three radiometers of each radiometer type. Data were analyzed with two-way analysis of variance/Tukey; alpha = 0.05. In general, both handheld radiometer types exhibited significantly different irradiance readings compared with the control meter. Additionally, readings between radiometer types were found to differ slightly, but were correlated. In general, the LED radiometer provided slightly lower irradiance readings than the halogen radiometer, irrespective of light source. With both types of handheld radiometers, the use of the larger-diameter light guides tended to overestimate the irradiance values as seen in the control, while smaller-diameter light guides tended to underestimate. The evaluated LED or halogen handheld radiometers may be used interchangeably to determine the irradiance of both LED and QTH visible-light-curing units. Measured differences between the two radiometer types were small and probably not clinically significant. However, the diameter of light guides may affect the accuracy of the radiometers, with larger-diameter light guides overestimating and smaller-diameter guides underestimating the irradiance value measured by the control instrument.

  3. Ultraviolet radiation and blue-light emissions from spotlights incorporating tungsten halogen lamps

    CERN Document Server

    MacKinlay, Alistair F; Whillock, M J

    1989-01-01

    This report summarises measurements of the ultraviolet radiation and blue-light emissions from eleven 'desk-top' tungsten halogen (quartz) lamps and one 'floor-standing' tungsten halogen (quartz) lamp available in the UK. Values of occupational hazard weighted and erythemally weighted ultraviolet radiation irradiance and measurements and relevant calculations of blue-light hazards are presented. It is concluded that the safety design of some desk-top tungsten halogen lamps is inadequate to prevent unnecessary exposure of the skin to potentially harmful ultraviolet radiation. It is recommended that all tungsten halogen lamps should have sufficient filtration to reduce their ultraviolet emissions to an acceptably low level. As long as the comfort aversion responses of the eye are respected, direct viewing of the lamps examined should not constitute a retinal hazard.

  4. Antimicrobial photodynamic therapy using chlorin e6 with halogen light for acne bacteria-induced inflammation.

    Science.gov (United States)

    Jeon, Yu-Mi; Lee, Hwan-Suk; Jeong, Dongjun; Oh, Hae-Keun; Ra, Kyu-Hwan; Lee, Mi-Young

    2015-03-01

    The present study was designed to evaluate the therapeutic potential of antimicrobial photodynamic therapy (PDT) using chlorin e6 with halogen light against acne bacteria-induced inflammation. Highly purified chlorin e6 (Ce6), as a second generation photosensitizer, was synthesized from Spirulina chlorophyll. To evaluate the antimicrobial property of Ce6-mediated PDT with halogen light, the broth microdilution method and two-color fluorescence assay were used. The free radicals generated upon irradiating Ce6 with halogen light were measured using 2,7-dichlorofluorescin diacetate. Propionibacterium acnes was intradermally injected into the left ear of the ICR mice, and the anti-inflammatory effect of Ce6-mediated PDT with halogen light was measured by the histological examination. The expressions of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) as well as pro-inflammatory cytokines were also measured by Western blotting. Chlorin e6-mediated PDT with halogen light (30,000 lx) inactivated various skin bacteria, including P. acnes in a dose-dependent manner. The MIC99 value against P. acnes (KCTC3314) of Ce6 with light was >0.49 μg/ml, whereas the MIC99 for Ce6 alone was >31.25 μg/ml. Ce6-mediated PDT suppressed the expression of P. acnes-induced pro-inflammatory cytokines and iNOS, but not COX-2 in a mouse model. This study showed a remarkable therapeutic effect of chlorin e6-mediated PDT with halogen light against P. acnes-induced inflammation. Our results suggest for the first time the potential of Ce6-mediated PDT with halogen light as a more effective and safer alternative treatment to antibiotic therapy against pathogenic infections of the skin. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Halogen light versus LED for bracket bonding: shear bond strength.

    Science.gov (United States)

    Carvalho, Paulo Eduardo Guedes; dos Santos, Valdemir Muzulon; Isber, Hassan; Cotrim-Ferreira, Flávio Augusto

    2013-02-15

    LED light-curing devices seek to provide a cold light activator which allows protocols of material polymerization with shorter duration. The present study aimed to evaluate the shear bond strength of bracket bonding using three types of light-curing devices: One with halogen light (Optilight Plus - Gnatus) and two with LEDs (Optilight CL - Gnatus and Elipar Freelight - 3M/ESPE). Comparing the results by analysis of variance, the Gnatus LED device showed an inferior statistical behavior in relation to other light sources, when activated by a short time. But, when it was used for 40 seconds, the polymerization results were consistent with the other evaluated sources. The device with the best average performance was the halogen light, followed by the 3M/ESPE LED. It was concluded that the LEDs may be indicated in orthodontic practice, as long as a protocol is used for the application of light with the activation time of 40 seconds.

  6. Comparative efficiency of plasma and halogen light sources on composite micro-hardness in different curing conditions.

    Science.gov (United States)

    Dietschi, D; Marret, N; Krejci, I

    2003-09-01

    Recent developments have led to the introduction of high power curing lights, which are claimed to greatly reduce the total curing time. This study evaluated the effectiveness of a plasma-curing device (Apollo 95 E) and a halogen device (Heliolux DLX), in different curing conditions. Vicker's micro-hardness values were performed on 1 and 2 mm thick composite discs cured in a natural tooth mold by direct irradiation or indirect irradiation through composite material (2 or 4 mm) and dental tissues (1 mm enamel or 2 mm enamel-dentin). Measures were, respectively, performed after a 1, 3, 6 s (SC, step curing mode) or 18 s (3xSC) exposure to the plasma light, and a 5, 10, 20 or 40 s exposure to the halogen light. With the PAC light used, a 3 s irradiation in the direct curing condition was necessary to reach hardness values similar to those obtained after a 40 s exposure to the halogen light. Using the indirect curing condition, hardness values reached after an 18 s exposure (3xSC mode) with the plasma light were either equivalent or inferior to those obtained with 40 s halogen irradiation. Direct polymerization with the plasma light used requires longer exposure times than those initially proposed by the manufacturer. The effectiveness of plasma generated light was lowered by composite or natural tissues, and therefore requires an important increase in the irradiation time when applied to indirect polymerization. The practical advantage of this polymerization method is less than expected, when compared to traditional halogen curing.

  7. Conventional and high intensity halogen light effects on water sorption and microhardness of orthodontic adhesives.

    Science.gov (United States)

    Uysal, Tancan; Basciftci, Faruk Ayhan; Sener, Yagmur; Botsali, Murat Selim; Demir, Abdullah

    2008-01-01

    To test the null hypothesis that when the equivalent total light energy is irradiated to three orthodontic adhesive resins, there is no difference between the microhardness and water sorption values regardless of the curing light sources. Samples were divided into six groups according to the combination of three orthodontic adhesives (Kurasper F, Light-Bond, Transbond XT) and two light intensities (quartz tungsten halogen [QTH] and high intensity quartz tungsten halogen [HQTH]). One half of each of the 40 samples of three adhesive pastes was polymerized for 20 seconds by a QTH light source, and the other half was polymerized for 10 seconds by a HQTH light source. Water sorption was determined and Vickers hardness was established with three measurements per sample at the top, center, and bottom. Statistical analysis was performed using two-way analysis of variance (ANOVA) with multiple comparisons (Tukey-HSD). Statistically significant differences were found among all adhesives for water sorption and hardness values cured with QTH and HQTH. The HQTH curing unit resulted in higher values than did the QTH. The highest water sorption values were observed for Kurasper F cured with HQTH and the lowest value was observed for Transbond XT cured with QTH. For microhardness Light-Bond cured with HQTH produced the highest values, and Transbond XT cured with QTH produced the lowest. When the equivalent total light energy is irradiated to three orthodontic adhesive resins, there are significant differences between the microhardness and water sorption values cured with the QTH and HQTH light source. The null hypothesis is rejected.

  8. Vibration and thermal vacuum qualification test results for a low-voltage tungsten-halogen light

    Science.gov (United States)

    Sexton, J. Andrew

    1991-01-01

    The results of a space flight qualification test program for a low-voltage, quartz tungsten-halogen light are presented. The test program was designed to qualify a halogen light for use in the Pool Boiling Experiment, a Get Away Special (GAS) payload that will be flown in the space shuttle payload bay. Vibration and thermal vacuum tests were performed. The test results indicated that the halogen light will survive the launch and ascent loads, and that the convection-free environment associated with the GAS payload system will not detrimentally affect the operation of the halogen light.

  9. Comparison of shear bond strength of orthodontic brackets bonded with halogen and plasma arc light curing

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein IndianJPsychiatry

    2012-01-01

    Conclusion: Using the plasma arc system is superior to other methods due to reduced curing time. Also, since in using the halogen light system, an increase in curing periods from different angles resulted in a significant increase in shear bond strength; it is advisable to apply the halogen light from different angles.

  10. Photoresponsive ionic liquid crystals assembled via halogen bond: en route towards light-controllable ion transporters.

    Science.gov (United States)

    Saccone, Marco; Palacio, Francisco Fernandez; Cavallo, Gabriella; Dichiarante, Valentina; Virkki, Matti; Terraneo, Giancarlo; Priimagi, Arri; Metrangolo, Pierangelo

    2017-10-13

    We demonstrate that halogen bonding (XB) can offer a novel approach for the construction of photoresponsive ionic liquid crystals. In particular, we assembled two new supramolecular complexes based on 1-ethyl-3-methylimidazolium iodides and azobenzene derivatives containing an iodotetrafluoro-benzene ring as XB donor, where the iodide anion acted as an XB acceptor. DSC and X-ray diffraction analyses revealed that the preferred stoichiometry between the XB donors and acceptors is 2 : 1, and that the iodide anions act as bidentate XB-acceptors, binding two azobenzene derivatives. Due to the high directionality of the XB, calamitic superanions are obtained, while the segregation occurring between the charged and uncharged parts of the molecules gives rise to a layered structure in the crystal lattice. Despite the fact that the starting materials are non-mesomorphic, the halogen-bonded supramolecular complexes exhibited monotropic lamellar liquid-crystalline phases over broad temperature ranges, as confirmed with polarized optical microscopy. Due to the presence of the azobenzene moieties, the LCs were photoresponsive, and a LC-to-isotropic phase transition could be obtained by irradiation with UV light. We envisage that the light-induced phase transition, in combination with the ionic nature of the LC, provides a route towards light-induced control over ion transport and conductance in these supramolecular complexes.

  11. Halogen light versus LED for bracket bonding: shear bond strength

    Directory of Open Access Journals (Sweden)

    Paulo Eduardo Guedes Carvalho

    2013-02-01

    Full Text Available INTRODUCTION: LED light-curing devices seek to provide a cold light activator which allows protocols of material polymerization with shorter duration. OBJECTIVE: The present study aimed to evaluate the shear bond strength of bracket bonding using three types of light-curing devices: One with halogen light (Optilight Plus - Gnatus and two with LEDs (Optilight CL - Gnatus and Elipar Freelight - 3M/ESPE. RESULTS: Comparing the results by analysis of variance, the Gnatus LED device showed an inferior statistical behavior in relation to other light sources, when activated by a short time. But, when it was used for 40 seconds, the polymerization results were consistent with the other evaluated sources. The device with the best average performance was the halogen light, followed by the 3M/ESPE LED. CONCLUSION: It was concluded that the LEDs may be indicated in orthodontic practice, as long as a protocol is used for the application of light with the activation time of 40 seconds.INTRODUÇÃO: os aparelhos de fotopolimerização por LED buscam proporcionar uma luz ativadora fria, que possibilite protocolos de polimerização do material com menor tempo de duração. OBJETIVO: avaliar a resistência à tração da colagem de braquetes, utilizando três tipos de aparelhos fotoativadores: um de luz halógena (Optilight Plus - Gnatus e outros dois de LED (Optilight CL - Gnatus; e Elipar Freelight - 3M/Espe. RESULTADOS: comparando os resultados por meio da análise de variância, o aparelho de LED Gnatus apresentou comportamento estatístico inferior em relação às outras fontes de luz, quando ativado por tempo reduzido. Já quando foi utilizado o tempo de 40 segundos, os resultados de polimerização foram compatíveis com as demais fontes avaliadas. O aparelho que apresentou melhor desempenho médio foi o de luz halógena, seguido pelo LED 3M/Espe. CONCLUSÃO: concluiu-se que os LEDs podem ser indicados na prática ortodôntica, uma vez que seja utilizado

  12. Influence of halogen irradiance on short- and long-term wear resistance of resin-based composite materials.

    LENUS (Irish Health Repository)

    Bhamra, Gurcharn S

    2009-02-01

    The Oregon Health Science University (OHSU) four-chamber oral wear simulator was used to examine the impact of halogen irradiance on the short- and long-term wear behavior of four-methacrylate resin-based composites (RBCs). The hypothesis proposed was that exacerbated wear would occur following the long-term wear of RBCs irradiated under non-optimized irradiance conditions.

  13. Comparison of shear bond strength of orthodontic brackets bonded with halogen and plasma arc light curing.

    Science.gov (United States)

    Toodehzaeim, Mohammad Hossein; Kazemi, Alireza Danesh; Aghili, Hossein Agha; Barzegar, Kazem; Fallahtafti, Taranom

    2012-05-01

    Reduced time and appropriate bond strength of brackets is one of the most important aspects of orthodontic treatments. Prolonged halogen light curing for bonding of brackets is undesirable, so the purpose of this study was to compare the shear bond strength of brackets bonded with halogen light and plasma arc system. MATERIALS AND MEHODS: This was an experimental in vitro study. A total of 60 intact premolar teeth were collected and divided into four groups. Stainless steel orthodontic brackets were bonded to them. In groups 1 and 2, curing was done using halogen light given for 20 seconds from two and four angles. In groups 3 and 4, curing was carried out using the plasma arc system for 6 seconds from two and four angles. The shear bond strength was recorded by Instron. The statistics of ANOVA, Tukey's test, and T-test were used in data analysis. There was a statistically significant difference in shear bond strength among the four groups (P = 0.043) and between group 1 with group 2 (P = 0.035). Yet, there was no statistically significant difference between brackets bonded with plasma arc and those bonded with halogen light or between the two groups of plasma arc. Using the plasma arc system is superior to other methods due to reduced curing time. Also, since in using the halogen light system, an increase in curing periods from different angles resulted in a significant increase in shear bond strength; it is advisable to apply the halogen light from different angles.

  14. Singlet oxygen production by combining erythrosine and halogen light for photodynamic inactivation of Streptococcus mutans.

    Science.gov (United States)

    Fracalossi, Camila; Nagata, Juliana Yuri; Pellosi, Diogo Silva; Terada, Raquel Sano Suga; Hioka, Noboru; Baesso, Mauro Luciano; Sato, Francielle; Rosalen, Pedro Luiz; Caetano, Wilker; Fujimaki, Mitsue

    2016-09-01

    Photodynamic inactivation of microorganisms is based on a photosensitizing substance which, in the presence of light and molecular oxygen, produces singlet oxygen, a toxic agent to microorganisms and tumor cells. This study aimed to evaluate singlet oxygen quantum yield of erythrosine solutions illuminated with a halogen light source in comparison to a LED array (control), and the photodynamic effect of erythrosine dye in association with the halogen light source on Streptococcus mutans. Singlet oxygen quantum yield of erythrosine solutions was quantified using uric acid as a chemical-probe in an aqueous solution. The in vitro effect of the photodynamic antimicrobial activity of erythrosine in association with the halogen photopolimerizing light on Streptococcus mutans (UA 159) was assessed during one minute. Bacterial cultures treated with erythrosine alone served as negative control. Singlet oxygen with 24% and 2.8% degradation of uric acid in one minute and a quantum yield of 0.59 and 0.63 was obtained for the erythrosine samples illuminated with the halogen light and the LED array, respectively. The bacterial cultures with erythrosine illuminated with the halogen light presented a decreased number of CFU mL(-1) in comparison with the negative control, with minimal inhibitory concentrations between 0.312 and 0.156mgmL(-1). The photodynamic response of erythrosine induced by the halogen light was capable of killing S. mutans. Clinical trials should be conducted to better ascertain the use of erythrosine in association with halogen light source for the treatment of dental caries. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Comparing colour discrimination and proofreading performance under compact fluorescent and halogen lamp lighting.

    Science.gov (United States)

    Mayr, Susanne; Köpper, Maja; Buchner, Axel

    2013-01-01

    Legislation in many countries has banned inefficient household lighting. Consequently, classic incandescent lamps have to be replaced by more efficient alternatives such as halogen and compact fluorescent lamps (CFL). Alternatives differ in their spectral power distributions, implying colour-rendering differences. Participants performed a colour discrimination task - the Farnsworth-Munsell 100 Hue Test--and a proofreading task under CFL or halogen lighting of comparable correlated colour temperatures at low (70 lx) or high (800 lx) illuminance. Illuminance positively affected colour discrimination and proofreading performance, whereas the light source was only relevant for colour discrimination. Discrimination was impaired with CFL lighting. There were no differences between light sources in terms of self-reported physical discomfort and mood state, but the majority of the participants correctly judged halogen lighting to be more appropriate for discriminating colours. The findings hint at the colour-rendering deficiencies associated with energy-efficient CFLs. In order to compare performance under energy-efficient alternatives of classic incandescent lighting, colour discrimination and proofreading performance was compared under CFL and halogen lighting. Colour discrimination was impaired under CFLs, which hints at the practical drawbacks associated with the reduced colour-rendering properties of energy-efficient CFLs.

  16. Identification of halogenated photoproducts generated after ultraviolet-irradiation of parabens and benzoates in water containing chlorine by solid-phase microextraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Alvarez-Rivera, Gerardo; Llompart, Maria; Garcia-Jares, Carmen; Lores, Marta

    2014-07-04

    This work presents a new solid-phase microextraction (SPME)-based approach to investigate the formation of halogenated by-products generated by the UV-induced photodegradation of parabens and their congener benzoates in water containing chlorine. Degradation of parent species, and further identification of their transformation by-products were monitored by gas chromatography coupled to mass spectrometry (GC/MS). In order to improve detectability, SPME was applied as a preconcentration step after UV-irradiation of target preservatives. Experiments performed with dechlorinated water, ultrapure water, and tap water showed that under UV-light, the presence of even low levels of free chlorine, increases the photodegradation rate of target preservatives, enhancing the formation of halogenated photoproducts. Monobrominated, dibrominated and bromochlorinated hydroxybenzoates were identified, and the transformation of benzoates into halogenated parabens was also confirmed. Bromination is expected to occur when free chlorine is present, due to the presence of traces of bromide in water samples. Five halogenated phenols (mainly brominated) were detected as breakdown photoproducts from both families of target preservatives. On the basis of the appearance of the aforementioned by-products, a tentative transformation pathway, consistent with the photoformation-photodecay kinetics of the by-products, is proposed herein for the first time. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. LED vs halogen light-curing of adhesive-precoated brackets.

    Science.gov (United States)

    Mirabella, Davide; Spena, Raffaele; Scognamiglio, Giovanni; Luca, Lombardo; Gracco, Antonio; Siciliani, Giuseppe

    2008-09-01

    To test the hypothesis that bonding with a blue light-emitting diode (LED) curing unit produces no more failures in adhesive-precoated (APC) orthodontic brackets than bonding carried out by a conventional halogen lamp. Sixty-five patients were selected for this randomized clinical trial, in which a total of 1152 stainless steel APC brackets were employed. In order to carry out a valid comparison of the bracket failure rate following use of each type of curing unit, each patient's mouth was divided into four quadrants. In 34 of the randomly selected patients, designated group A, the APC brackets of the right maxillary and left mandibular quadrants were bonded using a halogen light, while the remaining quadrants were treated with an LED curing unit. In the other 31 patients, designated group B, halogen light was used to cure the left maxillary and right mandibular quadrants, whereas the APC brackets in the remaining quadrants were bonded using an LED dental curing light. The bonding date, the type of light used for curing, and the date of any bracket failures over a mean period of 8.9 months were recorded for each bracket and, subsequently, the chi-square test, the Yates-corrected chi-square test, the Fisher exact test, Kaplan-Meier survival estimates, and the log-rank test were employed in statistical analyses of the results. No statistically significant difference in bond failure rate was found between APC brackets bonded with the halogen light-curing unit and those cured with LED light. However, significantly fewer bonding failures were noted in the maxillary arch (1.67%) than in the mandibular arch (4.35%) after each light-curing technique. The hypothesis cannot be rejected since use of an LED curing unit produces similar APC bracket failure rates to use of conventional halogen light, with the advantage of a far shorter curing time (10 seconds).

  18. Performance analysis of photoresistor and phototransistor for automotive’s halogen and xenon bulbs light output

    Science.gov (United States)

    Rammohan, A.; Kumar, C. Ramesh

    2017-11-01

    Illumination of any light is measured using a different kind of calibrated equipment’s available in the market such as a goniometer, spectral radiometer, photometer, Lux meter and camera based systems which directly display the illumination of automotive headlights light distribution in the unit of lux, foot-candles, lumens/sq. ft. and Lambert etc., In this research, we dealt with evaluating the photo resistor or Light Dependent Resistor (LDR) and phototransistor whether it is useful for sensing light patterns of Automotive Halogen and Xenon bulbs. The experiments are conducted during night hours under complete dark space. We have used the headlamp setup available in TATA SUMO VICTA vehicle in the Indian market and conducted the experiments separately for Halogen and Xenon bulbs under low and high beam operations at various degrees and test points within ten meters of distance. Also, we have compared the light intensity of halogen and xenon bulbs to prove the highest light intensity between halogen and Xenon bulbs. After doing a rigorous test with these two sensors it is understood both are good to sensing beam pattern of automotive bulbs and even it is good if we use an array of sensors or a mixed combination of sensors for measuring illumination purposes under perfect calibrations.

  19. Light-emitting diode vs halogen light curing of orthodontic brackets: a 15-month clinical study of bond failures.

    Science.gov (United States)

    Krishnaswamy, N Rengarajan; Sunitha, Chakravarthi

    2007-10-01

    Previous in-vitro investigations reported no significant differences in the bond strength of brackets cured with conventional halogen lamps and those cured with light-emitting diodes (LED), even though LED curing times are much shorter. However, it is not known how LED curing performs in the oral cavity. The purpose of this randomized clinical trial was to evaluate the clinical performance of brackets cured with 2 light-curing units: a conventional halogen unit and an LED. Thirty patients treated with fixed appliances were included in this study. The bonding followed a contralateral quadrant pattern: in each patient, 2 quadrants were cured with the conventional halogen unit, and the other 2 quadrants were cured with the LED unit. The study had a single blind controlled design with a within-patient comparison of the 2 curing techniques, and the patients were allocated randomly. A total of 544 stainless steel brackets were examined for bracket failure. Location (tooth), cause, and date of failure were recorded over 15 months. Statistical analyses were performed with the Kaplan-Meier survival estimates and the log rank test. No statistically significant differences were found in total bond failure rate or in mean survival time between brackets cured with the halogen light and those cured with the LED. Neither were significant differences found between the 2 lights when the clinical performances of the maxillary and mandibular arches were compared, or when the posterior and anterior segments were compared. These results show that curing with an LED does not result in more bond failures or shorter time to failure when compared with conventional halogen light curing. Curing with an LED is an acceptable alternative to conventional halogen light curing.

  20. A Difference in Cutaneous Pigmentary Response to LED Versus Halogen Incandescent Visible Light: A Case Report from a Single Center, Investigational Clinical Trial Determining a Minimal Pigmentary Visible Light Dose.

    Science.gov (United States)

    Soleymani, Teo; Soter, Nicholas A; Folan, Lorcan M; Elbuluk, Nada; Okereke, Uchenna R; Cohen, David E

    2017-04-01

    BACKGROUND: While most of the attention regarding skin pigmentation has focused on the effects on ultraviolet radiation, the cutaneous effects of visible light (400 to 700nm) are rarely reported. In this report, we describe a case of painful erythema and induration that resulted from direct irradiation of UV-naïve skin with visible LED light in a patient with Fitzpatrick type II skin. METHODS AND RESULTS: A 24-year-old healthy woman with Fitzpatrick type II skin presented to our department to participate in a clinical study. As part of the study, the subject underwent visible light irradiation with an LED and halogen incandescent visible light source. After 5 minutes of exposure, the patient complained of appreciable pain at the LED exposed site. Evaluation demonstrated erythema and mild induration. There were no subjective or objective findings at the halogen incandescent irradiated site, which received equivalent fluence (0.55 Watts / cm2). The study was halted as the subject was unable to tolerate the full duration of visible light irradiation. CONCLUSION: This case illustrates the importance of recognizing the effects of visible light on skin. While the vast majority of investigational research has focused on ultraviolet light, the effects of visible light have been largely overlooked and must be taken into consideration, in all Fitzpatrick skin types. J Drugs Dermatol. 2017;16(4):388-392..

  1. An in vivo study to compare a plasma arc light and a conventional quartz halogen curing light in orthodontic bonding.

    Science.gov (United States)

    Pettemerides, A P; Sherriff, M; Ireland, A J

    2004-12-01

    The purpose of this study was to compare the effectiveness of a plasma arc lamp with a conventional tungsten quartz halogen lamp in orthodontic bonding. Twenty consecutive patients had their brackets bonded either with Transbond XT (n = 10) or Fuji Ortho LC (n = 10). In total, 352 teeth were bonded, 176 in each group. Using a randomized cross-mouth control study design, where diagonally opposite quadrants were assigned a particular treatment, the bonds were then either cured with the control light, namely a halogen lamp, or a plasma arc lamp. The halogen light was used for 20 seconds per tooth and the plasma arc lamp for 3 seconds per tooth. The measurement parameter used was bond failure and the patients were monitored for a period of 6 months following initial bond placement. In the Transbond XT group, the proportion of bond failures was 3.41 per cent for both the halogen and the plasma arc lamp. For the Fuji Ortho LC group, the proportions were 11.4 and 10.2 per cent, respectively. No difference was observed with respect to in-service bond failure proportions between bonds cured with the plasma arc or the conventional halogen lamp, irrespective of the bonding agent. Use of the plasma arc lamp could therefore lead to considerable savings in clinical time. However, this must be weighed against the increased purchase price of the plasma arc lamp.

  2. Cytotoxicity and oxidative stress caused by dental adhesive systems cured with halogen and LED lights.

    Science.gov (United States)

    Spagnuolo, Gianrico; Annunziata, Marco; Rengo, Sandro

    2004-06-01

    The aim of the present study was to investigate the cytotoxicity of two "one bottle" adhesive systems after polymerization with a conventional halogen or a light emitting diode (LED) lamp. We hypothesized that different polymerization sources might enhance the intracellular production of reactive oxygen species (ROS), leading to reduced cell survival. Two "one bottle" adhesive systems (Optibond Solo and Scotchbond One) were cured with a commercial halogen (Optilux 500) and an LED source (Elipar Freelight, 3 M). The specimens were extracted for 24 h in complete cell culture medium or in phosphate-buffered saline (PBS). Endothelial cells (ECV 304) were exposed to the extracts for 24 h and survival rates were evaluated by the MTT assay. Then, ROS generation was monitored by the oxidation-sensitive fluorescent probe 2'7'-dichlorofluorescin diacetate (DCFH-DA). Extracts from all materials except for Optibond Solo polymerized with the halogen lamp were rated significantly cytotoxic. Scotchbond One cured with LED was the most toxic material, which reduced cell survival to about 23% compared with control cultures. Significantly higher amounts of ROS were produced in cell cultures treated with adhesives polymerized with the LED lamp compared with the materials cured with the commercial halogen light source. We demonstrated that the production of intracellular ROS by extracts of the adhesive systems depended on the light sources used for curing of the materials. These results suggested a possible link between ROS production and cytotoxic activity.

  3. In vitro lingual bracket evaluation of indirect bonding with plasma arc, LED and halogen light.

    Science.gov (United States)

    Magno, A F F; Martins, R P; Vaz, L G; Martins, L P

    2010-02-01

    Evaluate the shear bond strength (SBS) and the adhesive remnant index (ARI) of indirect bonded lingual brackets using xenon plasma arc light, light-emitting diode (LED) and conventional quartz-tungsten-halogen light. Lingual brackets were bonded indirectly to 60 premolars divided to three groups according to the curing light used: Group 1, plasma arc for 6 s; Group 2, LED for 10 s; and Group 3, halogen light for 40 s. After bonding, the specimens were subjected to a shear force until debonding. The debonding pattern was assessed and classified according to the ARI scores. The mean shear bond strengths were accessed by anova followed by the Student-Newman-Keuls test for multiple comparisons. ARI scores were assessed using the chi-square test. The three groups showed significant differences (p plasma arc, during 60% of the time used for the LED, produced lower SBS than obtained with the latter. Using LED during 25% of the time of the halogen light produced lower SBS than obtained with the latter. These differences did not influence the debonding pattern and are clinically acceptable according to the literature.

  4. Plasma versus halogen light: the effect of different light sources on the shear bond strength of brackets.

    Science.gov (United States)

    Neugebauer, Stephanie; Jost-Brinkmann, Paul-Georg; Pätzold, Boris; Cacciafesta, Vittorio

    2004-05-01

    The aim of this study was to investigate differences between plasma and halogen light polymerization in relation to the attainable shear bond strength of brackets bonded with various adhesives. 720 brackets were divided into 72 different groups of n = 10. The brackets were bonded to 240 flat polished test specimens produced from bovine teeth, Pontor MPF alloy, and extra hard plaster (type III) respectively. Transbond XT, Kurasper F or Fuji Ortho LC served as adhesives to bond either ceramic (Transcend 6000) or stainless steel brackets (Mini Uni-Twin). 50% of all brackets were bonded with a minimum layer of adhesive, and the remaining 50% with an adhesive layer thickness of 1.0 mm. In 360 cases the adhesive was polymerized with a plasma light (PAC), and in a further 360 cases with a halogen light (Optilux 401). The light curing time was 10 s with plasma light and 40 s with halogen light. After 24 h of storage in deionized water at room temperature, all brackets were subjected to a shear bond strength test according to ISO standard 10477. The measured shear bond strength did not differ significantly between the two curing light sources. The 1 mm adhesive layer thickness group showed significantly higher shear bond strengths in comparison to the minimum layer thickness group.

  5. Comparison of halogen light and vibroacoustic stimulation on nonreactive fetal heart rate pattern.

    Science.gov (United States)

    Rahimikian, Fatemeh; Rahiminia, Tahereh; Modarres, Maryam; Mehran, Abbas

    2013-03-01

    One of the first-line assessment tools for fetal surveillance is nonstress test (NST), although it is limited by a high rate of false-nonreactive results. This study was performed to investigate if external stimulation from vibroacoustic and halogen light could help in provoking fetal responsiveness and altering NST results. This is a clinical trial. Sampling was done from April to July 2010. One hundred pregnant women with nonreactive NST for 20 min were allocated in two groups: Vibroacoustic stimulated NST (VNST, n = 50) who received vibration from a standard fetal vibratory stimulator and halogen light stimulated NST (LNST, n = 50) who received a halogen light source for 3 and 10 sec, respectively. Results were compared together and then compared to biophysical profile (BPP) scores as a backup test. We used Mann-Whitney U test, Chi-square test, and Fisher's exact test to compare the variables in the two groups through SPSS version 14. P vibroacoustic stimulation group changed to reactive patterns. Time to onset of the first acceleration (VNST: 2.17 min; LNST: 2.27 min) and the test duration (VNST: 4.91 min; LNST: 5.26 min) were the same in the two groups. In VNST 89.5% and in LNST 87.5% of nonreactivity followed by score 8 in BPP. There was no significant relation between stimulus NSTs and BPPs. Vibroacoustic and light stimulation offer benefits by decreasing the incidence of nonreactive results and reducing the test time. Both halogen light stimulation and vibroacoustic stimulation are safe and efficient in fetal well-being assessment services.

  6. Tooth bleaching using three laser systems, halogen-light unit, and chemical action agents

    Science.gov (United States)

    Dostalova, Tatjana; Jelinkova, Helena; Housova, Devana; Sulc, Jan; Nemec, Michal; Koranda, Petr; Miyagi, Mitsunobu; Shi, Yi-Wei; Matsuura, Yuji

    2004-09-01

    μThe study describes the preclinical experience with laser-activated bleaching agent for discolored teeth. Extracted human upper central incisors were selected, and in the bleaching experiment 35% hydrogen peroxide was used. Three various laser systems and halogen-light unit for activation of the bleaching agent were applied. They were Alexandrite laser (wavelength 750 nm and 375 nm - SHG), Nd:YAG laser (wavelength 1.064 m), and Er:YAG laser (wavelength 2.94 μm). The halogen-light unit was used in a standard regime. The enamel surface was analyzed in the scanning electron microscope. The method of chemical oxidation results in a 2-3 shade change in one treatment. The halogen-light units produced the same effect with shorter time of bleaching process (from 630 s to 300 s). The Alexandrite laser (750 nm) and bleaching agent helped to reach the desired color shade after a shorter time (400 s). Alexandrite laser (375 nm) and Nd:YAG laser had no effect on the longevity of the process of bleaching. Overheating of the chemical bleaching agent was visible after Er:YAG laser activation (195 s). Slight surface modification after bleaching process was detected in SEM.

  7. Evaluation of wear rate of dental composites polymerized by halogen or LED light curing units

    Directory of Open Access Journals (Sweden)

    Alaghehmand H.

    2006-08-01

    Full Text Available Background and Aim: Sufficient polymerization is a critical factor to obtain optimum physical properties and clinical efficacy of resin restorations. The aim of this study was to evaluate wear rates of composite resins polymerized by two different systems Light Emitting Diodes (LED to and Halogen lamps. Materials and Methods: In this laboratory study, 20 specimens of A3 Tetric Ceram composite were placed in brass molds of 2*10*10 mm dimensions and cured for 40 seconds with 1 mm distance from surface. 10 specimens were cured with LED and the other 10 were cured with Halogen unit. A device with the ability to apply force was developed in order to test the wear of composites. After storage in distilled water for 10 days, the specimens were placed in the wear testing machine. A chrome cobalt stylus with 1.12 mm diameter was applied against the specimens surfaces with a load of 2 kg. The weight of each samples before and after 5000, 10000, 20000, 40000, 80000 and 120000 cycles was measured using an electronic balance with precision of 10-4 grams. Data were analyzed using t test and paired t test. P0.05. Conclusion: Based on the results of this study, LED and halogen light curing units resulted in a similar wear rate in composite resin restorations.

  8. Cross-over trial of fetal heart rate response to halogen light and vibroacoustic stimulation.

    Science.gov (United States)

    Bolnick, Jay M; Garcia, Greg; Fletcher, Beverly G; Rayburn, William F

    2006-04-01

    The purpose of this study was to compare the effect of halogen light and vibroacoustic stimulation on fetal heart rate (FHR) responsiveness and on nonstress test (NST) results. Sixty consecutively-chosen patients between 33 and 39 weeks of gestation underwent an NST on at least three weekly occasions. Each received halogen light (Vector Compact Sport Spot, Ft Lauderdale, FL, USA), vibroacoustic (SolaTone Artificial Larynx, Temecula, CA, USA), and no stimulation in a randomized order. The transabdominal light or vibroacoustic stimulation lasted for 10 seconds. If no initial FHR acceleration occurred, then the stimulus was repeated 10 minutes later up to a maximum of three times. The investigators who interpreted the FHR patterns were blinded as to the type of stimulus used. Reactive results were present in 171 tests (vibroacoustic: 98.3%; light: 96.6%; none: 93.3%). Compared with no stimulation, the mean difference in time from the onset of recorded "stimulation" to the first FHR acceleration was shorter (p vibroacoustic stimulation (2.6 minutes, 95% CI 0.8-4.4 minutes). The mean time difference until a reactive result was also shorter (p vibroacoustic stimulation (2.4 minutes, 95% CI 0.1-4.7 minutes) than with no stimulation. The need for repeated stimulation during each test was infrequent (light: 5.0%; vibroacoustic: 3.3%). No adverse effect from external stimulation was noted on the FHR tracing. Halogen light stimulation is an acceptable alternative to vibroacoustic stimulation in provoking a more rapid fetal heart rate response and in shortening the time before a reactive nonstress test result.

  9. Polymerization of a dual-cured cement through ceramic: LED curing light vs halogen lamp.

    Science.gov (United States)

    Lopes, Lawrence Gonzaga; Franco, Eduardo Batista; Name Neto, Abrão; Herrera, Francyle S; Kurachi, Cristina; Castañeda-Espinosa, Juan C; Lauris, José Roberto Pereira

    2004-12-01

    The aim of this study was to investigate the influence of light source, LED unit and halogen lamp (HL), on the effectiveness of Enforce dual-cured cement cured under a ceramic disc. Three exposure times (60, 80 and 120 s) were also evaluated. Two experimental groups, in which the polymerization of the dual-cured cement was performed through a ceramic disc, and two control groups, in which the polymerization of the dual-cured cement was performed directly without presence of ceramic disc were subdivided into three subgroups (three different exposure times), with five specimens each: G1A- HL 60s; G1B- HL 80s; G1C- HL 120s; G2A- LED 60s; G2B- LED 80s; G2C- LED 120s; and control groups: G3A- HL 60s; G3B- HL 80s; G3C- HL 120s; G4A- LED 60s; G4B- LED 80s and G4C- LED 120s. Cement was applied in a steel matrix (4mm diameter, 1.2mm thickness). In the experimental groups, a ceramic disc was placed on top. The cement was light-cured through the ceramic by a HL and LED, however, the control groups were cured without the ceramic disc. The specimens were stored in a light-proof container at 37ºC for 24 hours, then Vickers hardness was determined. A four-way ANOVA and Tukey test (p£ 0.05) were performed. All specimens cured by LED for 60s showed inferior values compared with the halogen groups. In general, light-curing by LED for 80s and 120s was comparable to halogen groups (60s and 80s) and their control groups. LED technology can be viable for light-curing through conventional ceramic indirect restorations, when curing time is increased in relation to HL curing time.

  10. Orthodontic bracket shear bond strengths produced by two high-power light-emitting diode modes and halogen light.

    Science.gov (United States)

    Türkkahraman, Hakan; Küçükeşmen, H Cenker

    2005-09-01

    The aim of this in vitro study was to compare the shear bond strength of orthodontic brackets cured with two different high-power light-emitting diode (LED) polymerization modes with traditional halogen polymerization. A total of forty-five extracted human premolar teeth were randomly divided into three groups. Each group consisted of 15 teeth mounted in an acrylic block. Following a standard enamel etching protocol, orthodontic brackets were cured on the first group of teeth with fast-mode LED, the second group with soft-start mode LED, and on the last group with a halogen light. After bonding, the shear bond strengths of the brackets were tested with a universal testing machine. The results showed that brackets cured with soft-start mode LED produced the highest shear bond strengths (23.86 +/- 6.20 MPa). No significant difference was found between fast-mode LED (17.14 +/- 5.75 MPa) and the halogen group (17.38 +/- 5.41 MPa) (P > .05). The LED is effective for bonding metal brackets to teeth, and the soft-start mode gives higher bond strengths than the fast mode.

  11. LED and Halogen Light Transmission through a CAD/CAM Lithium Disilicate Glass-Ceramic.

    Science.gov (United States)

    Pereira, Carolina Nemesio de Barros; De Magalhães, Cláudia Silami; Daleprane, Bruno; Peixoto, Rogéli Tibúrcio Ribeiro da Cunha; Ferreira, Raquel da Conceição; Cury, Luiz Alberto; Moreira, Allyson Nogueira

    2015-01-01

    The effect of thickness, shade and translucency of CAD/CAM lithium disilicate glass-ceramic on light transmission of light-emitting diode (LED) and quartz-tungsten-halogen units (QTH) were evaluated. Ceramic IPS e.max CAD shades A1, A2, A3, A3.5, high (HT) and low (LT) translucency were cut (1, 2, 3, 4 and 5 mm). Light sources emission spectra were determined. Light intensity incident and transmitted through each ceramic sample was measured to determine light transmission percentage (TP). Statistical analysis used a linear regression model. There was significant interaction between light source and ceramic translucency (p=0.008) and strong negative correlation (R=-0.845, pceramic thickness and TP. Increasing one unit in thickness led to 3.17 reduction in TP. There was no significant difference in TP (p=0.124) between shades A1 (ß1=0) and A2 (ß1=-0.45) but significant reduction occurred for A3 (ß1=-0.83) and A3.5 (ß1=-2.18). The interaction QTH/HT provided higher TP (ß1=0) than LED/HT (ß1=-2.92), QTH/LT (ß1=-3.75) and LED/LT (ß1=-5.58). Light transmission was more effective using halogen source and high-translucency ceramics, decreased as the ceramic thickness increased and was higher for the lighter shades, A1 and A2. From the regression model (R2=0.85), an equation was obtained to estimate TP value using each variable ß1 found. A maximum TP of 25% for QTH and 20% for LED was found, suggesting that ceramic light attenuation could compromise light cured and dual cure resin cements polymerization.

  12. Halogenated boron subphthalocyanines as light harvesting electron acceptors in organic photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Paul; Duraud, Amelie; Hancox, lan; Beaumont, Nicola; Hatton, Ross A.; Shipman, Michael; Jones, Tim S. [Department of Chemistry, University of Warwick, Coventry (United Kingdom); Mirri, Giorgio; Tucker, James H.R. [School of Chemistry, University of Birmingham, Edgbaston (United Kingdom)

    2011-05-15

    By tuning the frontier orbital energies through selective halogenation of the periphery of the organic framework, new light harvesting electron acceptors based on boron subphthalocyanine chloride (SubPc) have been made. Planar heterojunction organic photovoltaics made using a Cl{sub 6}-SubPc acceptor deliver an exceptionally high open-circuit voltage ({proportional_to}1.3 V), good power conversion efficiency ({proportional_to}2.7%) and improved operational stability in comparison to similar devices made using C{sub 60} as the acceptor material. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. In vitro evaluation of halogen light-activated vs chemically activated in-office bleaching systems.

    Science.gov (United States)

    Liang, Shanshan; Sa, Yue; Jiang, Tao; Ma, Xiao; Xing, Wenzhong; Wang, Zhejun; Wang, Yining

    2013-09-01

    To compare the tooth whitening efficacy, temperature and HP concentration changes induced by halogen light-activated and chemically activated in-office bleaching systems. Twenty-four extracted premolars were randomly divided into two groups (n = 12): Group BL (35% HP with halogen light activation) and Group OP (38% HP with chemical activation). Tooth color was measured by a spectrophotometer according to the CIE L*a*b* color space system. Temperatures of bleaching gels and pulp chambers during the bleaching process were monitored and recorded by a digital multimeter with K-type thermocouple. HP concentrations were tested before and after treatments by iodometry. ANOVA and paired t-test were used for statistical analyses at the significance of p post-treatment. Maximal temperature rise (ΔT) was found only in group BL, showing the increment of 2.55 and 2.02°C for bleaching gels and pulp chambers, respectively. HP concentrations were higher than baseline values for group OP (p temperature rise in pulp chambers.

  14. Conventional and high-intensity halogen light effects on polymerization shrinkage of orthodontic adhesives.

    Science.gov (United States)

    Sener, Yagmur; Uysal, Tancan; Basciftci, Faruk Ayhan; Demir, Abdullah; Botsali, Murat Selim

    2006-07-01

    The objectives of this study were to compare the polymerization shrinkage of three orthodontic adhesives. In addition we wanted to determine the effectiveness of the high-intensity quartz tungsten halogen (HQTH) in curing orthodontic adhesives on polymerization shrinkage with that of the quartz tungsten halogen (QTH). A total of 120 glass ring molds were prepared using a low-speed saw. The internal surface of the glass rings were roughened and etched. Adhesive pastes were placed into the glass molds, which were sandwiched between two glass slides. Samples were divided into six groups according to the combination of three orthodontic adhesives (Kurasper F, Light Bond, and Transbond XT) and two light intensities. One half of each 40 samples of three adhesive pastes was polymerized for 20 seconds by a QTH (Hilux 350), and the other half was polymerized for 10 seconds by a HQTH (Optilux 501). The volumetric polymerization shrinkage for each system was measured through the specific density method modified by Puckett and Smith. Statistical analysis was performed using two-way analysis of variance for intergroup comparisons. The HQTH-curing unit resulted in a more polymerization shrinkage than did the QTH for all investigated adhesives. However, no statistically significant differences were found. The highest shrinkage was observed for Light Bond cured with HQTH (1.59 +/- 0.82%), and the lowest value was observed for Transbond XT cured with QTH (1.23 +/- 0.60%). There are no significant differences in polymerization shrinkage of the three investigated orthodontic adhesives when polymerized with a QTH or a HQTH.

  15. Comparative efficiency of plasma and halogen light sources on composite micro-hardness in different curing conditions

    OpenAIRE

    Dietschi, Didier; Marret, N; Krejci, Ivo

    2003-01-01

    Recent developments have led to the introduction of high power curing lights, which are claimed to greatly reduce the total curing time. This study evaluated the effectiveness of a plasma-curing device (Apollo 95 E) and a halogen device (Heliolux DLX), in different curing conditions.

  16. Comparative Evaluation of Shear Bond Strength and Debonding Characteristics using Conventional Halogen Light Curing Unit and LED Light Curing Unit: An in vitro Study

    Directory of Open Access Journals (Sweden)

    Amit Bhardwaj

    2013-01-01

    Conclusion: The result of this study showed promise for the orthodontic application of LED as light curing units and 20 seconds of exposure time is adequate for both LED and Halogen light, since increasing the curing time to 40 seconds showed no significant difference.

  17. Induction and prevention of micronuclei and chromosomal aberrations in cultured human lymphocytes exposed to the light of halogen tungsten lamps.

    Science.gov (United States)

    D'Agostini, F; Caimo, A; De Filippi, S; De Flora, S

    1999-07-01

    Previous studies have shown that the light emitted by halogen tungsten lamps contains UV radiation in the UV-A, UV-B and UV-C regions, induces mutations and irreparable DNA damage in bacteria, enhances the frequency of micronuclei in cultured human lymphocytes and is potently carcinogenic to the skin of hairless mice. The present study showed that the light emitted by an uncovered, traditional halogen lamp induces a significant, dose-related and time-related increase not only in micronuclei but also in chromosome-type aberrations, such as breaks, and even more in chromatid-type aberrations, such as isochromatid breaks, exchanges and isochromatid/chromatid interchanges, all including gaps or not, in cultured human lymphocytes. All these genotoxic effects were completely prevented by shielding the same lamp with a silica glass cover, blocking UV radiation. A new model of halogen lamp, having the quartz bulb treated in order to reduce the output of UV radiation, was considerably less genotoxic than the uncovered halogen lamp, yet induction of chromosomal alterations was observed at high illuminance levels.

  18. Solar light irradiation significantly reduced cytotoxicity and disinfection byproducts in chlorinated reclaimed water.

    Science.gov (United States)

    Lv, Xiao-Tong; Zhang, Xue; Du, Ye; Wu, Qian-Yuan; Lu, Yun; Hu, Hong-Ying

    2017-11-15

    Chlorinated reclaimed water is widely used for landscaping and recreational purposes, resulting in human exposure to toxic disinfection byproducts. Although the quality of chlorinated reclaimed water might be affected by sunlight during storage, the effects of solar light irradiation on the toxicity remain unknown. This study investigated the changes in cytotoxicity and total organic halogen (TOX) of chlorinated reclaimed water exposed to solar light. Irradiation with solar light for 12 h was found to significantly reduce the cytotoxicity of chlorinated reclaimed water by about 75%, with ultraviolet light being responsible for the majority of this reduction. Chlorine residual in reclaimed water tended to increase the cytotoxicity, and the synergy between solar light and free chlorine could not enhance the reduction of cytotoxicity. Adding hydroxyl radical scavengers revealed that the contribution of hydroxyl radical to cytotoxicity reduction was limited. Solar light irradiation concurrently reduced TOX. The low molecular weight (1 kDa) fraction was probably caused by photoconversion from high toxic TOX to low toxic TOX. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. A Comparison of the Shear Bond Strength of Orthodontic Brackets Bonded With Light-Emitting Diode and Halogen Light-Curing Units

    Directory of Open Access Journals (Sweden)

    SM. Abtahi

    2006-09-01

    Full Text Available Statement of the problem: Various methods such as light emitting diode (LED have been used to enhance the polymerization of resin-based orthodontic adhesives. There is a lack of information on the advantages and disadvantages of different light curing systems.Purpose: The aim of this study was to compare the effect of LED and halogen light curing systems on the shear bond strength of orthodontic brackets.Materials and Methods: Forty extracted human premolars were etched with 37% phosphoric acid and cleansed with water spray and air dried. The sealant was applied on the tooth surface and the brackets were bonded using Transbond adhesive (3M Unitek,Monrovia, Calif. Adhesives were cured for 40 and 20 seconds with halogen (Blue Light, APOZA, Taiwan and LED (Blue dent, Smart, Yugoslavia light-curing systems,respectively. Specimens were thermocycled 2500 times (from 5 to 55 °C and the shear bond strength of the adhesive system was evaluated with an Universal testing machine (Zwick GmbH, Ulm, Germany at a crosshead speed of 1 mm/min until the bracketswere detached from the tooth. Adhesive remnant index (ARI scores were determined after bracket failure. The data were submitted to statistical analysis, using Mann-Whitney analysis and t-test.Results: No significant difference was found in bond strength between the LED and halogen groups (P=0.12. A significant difference was not observed in the adhesive remnant index scores between the two groups (P=0.97.Conclusion: Within the limitations of this in vitro study, the shear bond strength of resin-based orthodontic adhesives cured with a LED was statistically equivalent to those cured with a conventional halogen-based unit. LED light-curing units can be suggested for the polymerization of orthodontic bonding adhesives.

  20. Effect of light-tip distance on the shear bond strengths of resin-modified glass ionomer cured with high-intensity halogen, light-emitting diode, and plasma arc lights.

    Science.gov (United States)

    Sfondrini, Maria Francesca; Cacciafesta, Vittorio; Scribante, Andrea; Boehme, Andreas; Jost-Brinkmann, Paul-Georg

    2006-04-01

    The purpose of this study was to assess the effect of light-tip distance on the shear bond strength and the failure site of brackets cured with 3 light-curing units (high-intensity halogen, light-emitting diode, and plasma arc). One hundred thirty-five bovine mandibular permanent incisors were randomly allocated to 9 groups of 15 specimens each. Stainless steel brackets (Victory Series, Unitek/3M, Monrovia, Calif) were bonded with a resin-modified glass-ionomer (Fuji Ortho LC, GC Europe, Leuven, Belgium) to the teeth, and each curing light was tested at 3 distances from the bracket: 0, 3, and 6 mm. After bonding, all samples were stored in distilled water at room temperature for 24 hours and subsequently tested for shear bond strength. When the 3 light-curing units were compared at a light-tip distance of 0mm, they showed no significantly different shear bond strengths. At a light-tip distance of 3 mm, no significant differences were found between the halogen and plasma arc lights, but both lights showed significantly higher shear bond strengths than the light-emitting diode light. At a light-tip distance of 6 mm, no significant differences were found between the halogen and light-emitting diode lights, but both showed significantly lower bond strengths than the plasma arc light. When the effect of the light-tip distance on each light-curing unit was evaluated, the halogen and light-emitting diode lights showed no significant differences among the 3 distances. However, the plasma arc light produced significantly higher shear bond strengths at a greater light-tip distance. No significant differences were found among the adhesive remnant index scores of the various groups, except with the LED light at a distance of 3 mm. In hard-to-reach areas, the plasma arc curing light is suggested for optimal curing efficiency.

  1. A comparative evaluation of the shear bond strength of five different orthodontic bonding agents polymerized using halogen and light-emitting diode curing lights: an in vitro investigation.

    Science.gov (United States)

    Banerjee, Sujoy; Banerjee, Rajlakshmi

    2011-01-01

    With the introduction of photosensitive (light-activated) restorative materials in orthodontics, various methods have been suggested to enhance the polymerization of the materials used, including use of more powerful light curing devices. Bond strength is an important property and determines the amount of force delivered and the treatment duration. Many light-cured bonding materials have become popular but it is the need of the hour to determine the bonding agent that is the most efficient and has the desired bond strength. To evaluate and compare the shear bond strengths of five different orthodontic light cure bonding materials cured with traditional halogen light and low-intensity light-emitting diode (LED) light curing unit. 100 human maxillary premolar teeth, extracted for orthodontic purpose, were used to prepare the samples. 100 maxillary stainless steel bicuspid brackets of 0.018 slot of Roth prescription, manufactured by D-tech Company, were bonded to the prepared tooth surfaces of the mounted samples using five different orthodontic bracket bonding light-cured materials, namely, Enlight, Fuji Ortho LC (resin-modified glass ionomer cement), Orthobond LC, Relybond, and Transbond XT. The bond strength was tested on an Instron Universal testing machine (model no. 5582). In Group 1 (halogen group), Enlight showed the highest shear bond strength (16.4 MPa) and Fuji Ortho LC showed the least bond strength (6.59 MPa) (P value 0.000). In Group 2 (LED group), Transbond showed the highest mean shear bond strength (14.6 MPa) and Orthobond LC showed the least mean shear bond strength (6.27 MPa) (P value 0.000). There was no statistically significant difference in the shear bond strength values of all samples cured using either halogen (mean 11.49 MPa) or LED (mean 11.20 MPa), as the P value was 0.713. Polymerization with both halogen and LED resulted in shear bond strength values which were above the clinically acceptable range given by Reynolds. The LED light curing

  2. A comparative evaluation of the shear bond strength of five different orthodontic bonding agents polymerized using halogen and light-emitting diode curing lights: An in vitro investigation

    Directory of Open Access Journals (Sweden)

    Sujoy Banerjee

    2011-01-01

    Full Text Available Purpose: With the introduction of photosensitive (light-activated restorative materials in orthodontics, various methods have been suggested to enhance the polymerization of the materials used, including use of more powerful light curing devices. Bond strength is an important property and determines the amount of force delivered and the treatment duration. Many light-cured bonding materials have become popular but it is the need of the hour to determine the bonding agent that is the most efficient and has the desired bond strength. Aim: To evaluate and compare the shear bond strengths of five different orthodontic light cure bonding materials cured with traditional halogen light and low-intensity light-emitting diode (LED light curing unit. Materials and Methods: 100 human maxillary premolar teeth, extracted for orthodontic purpose, were used to prepare the samples. 100 maxillary stainless steel bicuspid brackets of 0.018 slot of Roth prescription, manufactured by D-tech Company, were bonded to the prepared tooth surfaces of the mounted samples using five different orthodontic bracket bonding light-cured materials, namely, Enlight, Fuji Ortho LC (resin-modified glass ionomer cement, Orthobond LC, Relybond, and Transbond XT. The bond strength was tested on an Instron Universal testing machine (model no. 5582. Results: In Group 1 (halogen group, Enlight showed the highest shear bond strength (16.4 MPa and Fuji Ortho LC showed the least bond strength (6.59 MPa (P value 0.000. In Group 2 (LED group, Transbond showed the highest mean shear bond strength (14.6 MPa and Orthobond LC showed the least mean shear bond strength (6.27 MPa (P value 0.000. There was no statistically significant difference in the shear bond strength values of all samples cured using either halogen (mean 11.49 MPa or LED (mean 11.20 MPa, as the P value was 0.713. Conclusion: Polymerization with both halogen and LED resulted in shear bond strength values which were above the

  3. Remarkable effect of halogenation of aromatic compounds on efficiency of nanowire formation through polymerization/crosslinking by high-energy single particle irradiation

    Science.gov (United States)

    Horio, Akifumi; Sakurai, Tsuneaki; Kayama, Kazuto; Lakshmi, G. B. V. S.; Kumar Avasthi, Devesh; Sugimoto, Masaki; Yamaki, Tetsuya; Chiba, Atsuya; Saito, Yuichi; Seki, Shu

    2018-01-01

    Irradiation of high-energy ion particles on organic films induced solid-state polymerization and crosslinking reactions of the materials along the ion trajectories, resulting in the formation of insoluble uniform nanowires with a precise diameter. The nanowires were isolated by the development process i.e. the irradiated film was immersed in organic solvents, and their morphology was visualized by atomic force microscopy. The target organic materials are 4-vinyltriphenylamine, poly(4-vinyltriphenylamine), and polystyrene derivatives with/without the partial substitutions by halogen atoms. It was found that 4-vinyltriphenylamines, in spite of their small molecular sizes, afforded nanowires more clearly than poly(4-vinyltriphenylamine)s. Moreover, the efficiency of demonstrated polymerization/crosslinking reactions obviously depends on the substituted halogen atom species. The averaged diameters of nanowires from bromo- or iodo- substituted 4-vinyltriphenylamine (9.3 and 9.4 nm, respectively) were larger than that obtained from simple 4-vinyltriphenylamine (6.8 nm). The remarkable effect of halogenation of aromatic compounds on the efficiency of the radiation-induced reactions was also observed for polystyrene derivatives. This contrast was considered to originate from the sum of the efficiency of elementary reactions including dissociative electron attachment.

  4. Light irradiance and spectral distribution effects on cyanobacterial hydrogen production

    Science.gov (United States)

    Fatihah Salleh, Siti; Kamaruddin, Azlina; Hekarl Uzir, Mohamad; Rahman Mohamed, Abdul; Halim Shamsuddin, Abdul

    2016-03-01

    Light is an essential energy source for photosynthetic cyanobacteria. Changes in both light irradiance and spectral distribution will affect their photosynthetic productivity. Compared to the light irradiance, little investigations have been carried out on the effect of light spectra towards cyanobacterial hydrogen production. Hence, this work aims to investigate the effects of both light quantity and quality on biohydrogen productivity of heterocystous cyanobacterium, A.variabilis. Under white light condition, the highest hydrogen production rate of 31 µmol H2 mg chl a -1 h-1 was achieved at 70 µE m-2 s-1. When the experiment was repeated at the same light irradiance but different light spectra of blue, red and green, the accumulations of hydrogen were significantly lower than the white light except for blue light. As the light irradiance was increased to 350 µE m-2 s-1, the accumulated hydrogen under the blue light doubled that of the white light. Besides that, an unusual prolongation of the hydrogen production up to 120 h was observed. The results obtained suggest that blue light could be the most desirable light spectrum for cyanobacterial hydrogen production.

  5. Damage of yeast cells induced by pulsed light irradiation.

    Science.gov (United States)

    Takeshita, Kazuko; Shibato, Junko; Sameshima, Takashi; Fukunaga, Sakae; Isobe, Seiichiro; Arihara, Keizo; Itoh, Makoto

    2003-08-15

    DNA damage, such as formation of single strand breaks and pyrimidine dimers was induced in yeast cells after irradiation by pulsed light, which were essentially the same as observed with continuous ultraviolet (UV) light. The UV-induced DNA damage is slightly higher than seen with pulsed light. However, increased concentration of eluted protein and structural change in the irradiated yeast cells were observed only in the case of pulsed light. A difference in the inactivation effect between pulsed light and UV light was found and this suggested cell membrane damage induced by pulsed light irradiation. It is proposed that pulsed light can be used as an effective sterilizing method for the yeast Saccharomyces cerevisiae.

  6. Nonimaging light concentrator with uniform irradiance

    Science.gov (United States)

    Winston, Roland; Gee, Randy C.

    2003-04-01

    A nonimaging light concentrator system including a primary collector of light, an optical mixer disposed near the focal zone for collecting light from the primary collector, the optical mixer having a transparent entrance aperture, an internally reflective housing for substantially total internal reflection of light, a transparent exit aperture and an array of photovoltaic cells disposed near the transparent exit aperture.

  7. Plant Growth Under Light Emitting Diode Irradiation.

    Science.gov (United States)

    Tennessen, Daniel John

    Plant growth under light emitting diodes (LEDs) was investigated to determine if LEDs would be useful to provide radiant energy for two plant processes, photosynthesis and photomorphogenesis. Photosynthesis of tomato (Lycopersicon esculentum L.) and Kudzu (Pueraria lobata (Willd) Ohwi.) was measured using photons from LEDs to answer the following: (1) Are leaves able to use red LED light for photosynthesis? and (2) Is the efficiency of photosynthesis in pulsed light equal to that of continuous light? In 175 Pa CO _2, or in response to changes in CO _2,tomato (Lycopersicon esculentum Mill.) and transformed tobacco and tomato (expressing oat phytochrome-A) was assessed by growing plants under red LED lamps in an attempt to answer the following: (1) What is the developmental response of non-transformed and transformed tobacco to red LED light? and (2) Can tomato plants that grow tall and spindly in red LED light be made to grow short by increasing the amount of phytochrome-A? The short phenotype of transformed tobacco was not evident when plants were grown in LED light. Addition of photons of far-red or blue light to red light resulted in short transformed tobacco. Tomato plants grew three times as tall and lacked leaf development in LED versus white light, but transformed tomato remained short and produced fruit under LED light. I have determined that the LED photons are useful for photosynthesis and that the photon efficiency of photosynthesis is the same in pulsed as in continuous light. From responses of tobacco, I concluded that the P_{ rm r} form of phytochrome-A and the phytochrome cycling rate mediate responses. In tomato, increased amounts of Phytochrome-A prevented stem elongation and caused chlorophyll accumulation in LED light.

  8. The effect of red light irradiation on spermatozoa DNA

    Science.gov (United States)

    Chow, Kay W.; Preece, Daryl; Gomez-Godinez, Veronica; Berns, Michael W.

    2016-09-01

    A key goal in the conservation of endangered species is to increase successful reproduction. In cases where traditional methods of in vitro fertilization are unsuccessful, new methods of assisted reproduction are needed. One option is selective fertilization via optically trapped sperm. A more passive option is red light irradiation. Red light irradiation has been shown to increase sperm motility, thus increasing fertilizing potential. However, there is some concern that exposure to laser irradiation induces the production of oxidative species in cells, which can be damaging to DNA. In order to test the safety of irradiating sperm, sperm samples were exposed to 633 nm laser light and their DNA were tested for oxidative damage. Using fluorescence microscopy, antibody staining, and ELISA to detect oxidative DNA damage, it was concluded that red light irradiation does not pose a safety risk to sperm DNA. The use of red light on sperm has potential in both animal conservation and human reproduction techniques. This method can also be used in conjunction with optical trapping for viable sperm selection.

  9. Comparison of bond strength between orthodontic brackets bonded with halogen and plasma arc curing lights: an in-vitro and in-vivo study.

    Science.gov (United States)

    Signorelli, Michael D; Kao, Elizabeth; Ngan, Peter W; Gladwin, Marcia A

    2006-02-01

    This study assessed in-vitro shear bond strength and in-vivo survival rate of orthodontic brackets bonded with either a halogen or a plasma arc light. Ninety extracted premolars were divided into 6 groups of 15. Stainless steel brackets were bonded to the teeth by using either a halogen light with a 20-second curing time or a plasma arc light with a 2-, 6-, or 10-second curing time. Brackets were debonded either within 30 minutes of bonding or after thermocycling for 24 hours. Bond strengths were tested on a testing machine at a crosshead speed of 1 mm/minute. The bracket failure interface was measured with a modified adhesive remnant index score. Data were analyzed by using ANOVA and Tukey-Kramer multiple comparison tests. For the in-vivo study, a split-arch design was used to determine the bracket-failure rate and distribution in 25 patients. The patients were followed for a mean period of 1.1 years (386 days). Survival analysis was carried out to compare the failure rates of the 2 techniques. No significant differences in bond strengths were found 30 minutes after bonding between the halogen light (13.6 +/- 3.8 MPa) and the plasma arc light with 2-, 6-, or 10-second curing times (9.6 +/- 2.9, 14.2 +/- 4.6, 16.0 +/- 3.0 MPa, respectively). Similar bond strengths were also found between the halogen light with a 20-second (16.1 +/- 3.6 MPa) curing time and plasma arc light with 6 seconds (18.2 +/- 4.6 MPa) of curing time after 24 hours of thermocycling. For the in-vivo study, no significant difference was found in bracket failure rates between the 2 light sources (4.9% in both groups). No significant differences were found between ARI scores for the halogen light and the plasma arc light at either 30 minutes or 24 hours after debonding. These results indicate that the plasma arc light with a 6-second curing time can produce similar bond strength and bracket-failure rates as the halogen light that requires a longer curing time.

  10. Influence of the light source on the low-irradiance performance of Cu(In,Ga)Se{sub 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Virtuani, A.; Lotter, E.; Powalla, M. [Zentrum fuer Sonnenenergie- und Wasserstoff- Forschung Baden-Wuerttemberg (ZSW) Industriestr. 6, 70565 Stuttgart (Germany)

    2006-09-06

    Illumination intensities in indoor environments are usually given in terms of lux, a unit of measurement which only takes into account the spectral distribution of the light source in the sensitivity range of the human eye (380-780nm). At a given level of illuminance, however, the performance of a solar cell will strongly depend on the spectral distribution of the incoming light and on its spectral response. This work considers the spectral distribution of some typical light sources encountered in indoor environments (natural daylight/AM 1.5, fluorescent tube, halogen lamp with and without cold reflector, and the common incandescent lamp) and calculates the actual amount of light available to a generic solar cell. We then calculate the performance for different indoor illumination levels and spectra of a Cu(In,Ga)Se{sub 2} solar cell especially optimised for low-irradiance conditions. Considering as a reference the performance of the cell under a AM 1.5 spectrum at a given level of illuminance, we can expect the performance of the cell to be reduced by a factor 3 and 2, respectively, when using a fluorescent tube and a halogen lamp with cold reflector as the light source, and to be increased by a factor 2 to 3 if the cell is operated under a halogen/incandescent lamp. (author)

  11. Effects of blue light irradiation on human dermal fibroblasts.

    Science.gov (United States)

    Opländer, Christian; Hidding, Sarah; Werners, Frauke B; Born, Matthias; Pallua, Norbert; Suschek, Christoph V

    2011-05-03

    Previous studies have reported that separately from UV-radiation also blue light influences cellular physiology in different cell types. However, little is known about the blue light action spectrum. The purpose of this study was to investigate effects of blue light at distinct wavelengths (410, 420, 453, 480 nm) emitted by well defined light-emitting-diodes on viability, proliferation and antioxidative capacity of human dermal fibroblasts. We found that irradiation with blue light (410, 420 nm) led to intracellular oxidative stress and toxic effects in a dose and wavelength dependent manner. No toxicity was observed using light at 453 nm and 480 nm. Furthermore, blue light (410, 420, 453 nm) at low doses reduced the antioxidative capacity of fibroblasts. At non-toxic doses, irradiations at 410, 420 and 453 nm reduced proliferation indicating a higher susceptibility of proliferating fibroblasts to blue light. Our results show that blue light at different wavelengths may induce varying degrees of intracellular oxidative stress with different physiological outcome, which could contribute to premature skin photoaging. On the other hand, the use of blue light due to its antiproliferative and toxic properties may represent a new approach in treatment and prevention of keloids, hypertrophic scars and fibrotic skin diseases. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Enhancement of visible light irradiation photocatalytic activity of ...

    Indian Academy of Sciences (India)

    SrTiO₃ and Pt/SrTiO₃ nanoparticles were characterized by XRD, XPS, TEM, BET surface area UV–Vis and PL techniques in order to explore their chemical and physical properties. The visible light irradiation photocatalyticperformances of SrTiO₃ nanoparticles and Pt/SrTiO₃ nanoparticles for photocatalytic oxidation of ...

  13. Micro-leakage of a Fissure Sealant Cured Using Quartz-tungsten-halogen and Plasma Arc Light Curing Units.

    Science.gov (United States)

    Bahrololoomi, Zahra; Soleimani, Ali Asghar; Jafari, Najmeh; Varkesh, Bentolhoda

    2014-01-01

    Background and aims. Newer curing units such as plasma arc can polymerize the sealants in much shorter curing times. The aim of this study was to compare the effect of two different curing units on the micro-leakage of a fissure sealant material. Materials and methods. Sixty two extracted premolars without caries were randomly divided into two groups of 31 samples. Occlusal surfaces of all teeth were cleansed. Then, teeth surfaces were etched by 37% phosphoric acid. After rinsing and drying, occlusal surfaces of teeth were sealed by a fissure sealant. The sealant was then cured using either a halogen light curing unit or a plasma arc curing light. After sealing, the teeth were thermocycled for 500 cycles. The teeth were then sectioned and examined for micro-leakage. Statistical analyses were performed with Mann-Whitney test. Results. There was no significant difference between two groups regarding micro-leakage (P = 0.42). Conclusion. Results showed that there was no significant difference between two different curing units. Therefore, plasma arc unit might be a useful alternative for sealant polymerization.

  14. On Cherenkov light production by irradiated nuclear fuel rods

    Science.gov (United States)

    Branger, E.; Grape, S.; Jacobsson Svärd, S.; Jansson, P.; Andersson Sundén, E.

    2017-06-01

    Safeguards verification of irradiated nuclear fuel assemblies in wet storage is frequently done by measuring the Cherenkov light in the surrounding water produced due to radioactive decays of fission products in the fuel. This paper accounts for the physical processes behind the Cherenkov light production caused by a single fuel rod in wet storage, and simulations are presented that investigate to what extent various properties of the rod affect the Cherenkov light production. The results show that the fuel properties have a noticeable effect on the Cherenkov light production, and thus that the prediction models for Cherenkov light production which are used in the safeguards verifications could potentially be improved by considering these properties. It is concluded that the dominating source of the Cherenkov light is gamma-ray interactions with electrons in the surrounding water. Electrons created from beta decay may also exit the fuel and produce Cherenkov light, and e.g. Y-90 was identified as a possible contributor to significant levels of the measurable Cherenkov light in long-cooled fuel. The results also show that the cylindrical, elongated fuel rod geometry results in a non-isotropic Cherenkov light production, and the light component parallel to the rod's axis exhibits a dependence on gamma-ray energy that differs from the total intensity, which is of importance since the typical safeguards measurement situation observes the vertical light component. It is also concluded that the radial distributions of the radiation sources in a fuel rod will affect the Cherenkov light production.

  15. Converting a conventional wired-halogen illuminated indirect ophthalmoscope to a wireless-light emitting diode illuminated indirect ophthalmoscope in less than 1000/- rupees.

    Science.gov (United States)

    Kothari, Mihir; Kothari, Kedar; Kadam, Sanjay; Mota, Poonam; Chipade, Snehal

    2015-01-01

    To report the "do it yourself" method of converting an existing wired-halogen indirect ophthalmoscope (IO) to a wireless-light emitting diode (LED) IO and report the preferences of the patients and the ophthalmologists. In this prospective observational study, a conventional IO was converted to wireless-LED IO using easily available, affordable electrical components. Conventional and the converted IO were then used to perform photo-stress test and take the feedback of subjects and the ophthalmologists regarding its handling and illumination characteristics. The cost of conversion to wireless-LED was 815/- rupees. Twenty-nine subjects, mean age 34.3 [formula in text] 10 years with normal eyes were recruited in the study. Between the two illumination systems, there was no statistical difference in the magnitude of the visual acuity loss and the time to recovery of acuity and the bleached vision on photo-stress test, although the visual recovery was clinically faster with LED illumination. The heat sensation was more with halogen illumination than the LED (P = 0.009). The ophthalmologists rated wireless-LED IO higher than wired-halogen IO on the handling, examination comfort, patient's visual comfort and quality of the image. Twenty-two (81%) ophthalmologists wanted to change over to wireless-LED IO. Converting to wireless-LED IO is easy, cost-effective and preferred over a wired-halogen indirect ophthalmoscope.

  16. Converting a conventional wired-halogen illuminated indirect ophthalmoscope to a wireless-light emitting diode illuminated indirect ophthalmoscope in less than 1000/- rupees

    Directory of Open Access Journals (Sweden)

    Mihir Kothari

    2015-01-01

    Full Text Available Aim: To report the "do it yourself" method of converting an existing wired-halogen indirect ophthalmoscope (IO to a wireless-light emitting diode (LED IO and report the preferences of the patients and the ophthalmologists. Subjects and Methods: In this prospective observational study, a conventional IO was converted to wireless-LED IO using easily available, affordable electrical components. Conventional and the converted IO were then used to perform photo-stress test and take the feedback of subjects and the ophthalmologists regarding its handling and illumination characteristics. Results: The cost of conversion to wireless-LED was 815/- rupees. Twenty-nine subjects, mean age 34.3 ΁ 10 years with normal eyes were recruited in the study. Between the two illumination systems, there was no statistical difference in the magnitude of the visual acuity loss and the time to recovery of acuity and the bleached vision on photo-stress test, although the visual recovery was clinically faster with LED illumination. The heat sensation was more with halogen illumination than the LED (P = 0.009. The ophthalmologists rated wireless-LED IO higher than wired-halogen IO on the handling, examination comfort, patient′s visual comfort and quality of the image. Twenty-two (81% ophthalmologists wanted to change over to wireless-LED IO. Conclusions: Converting to wireless-LED IO is easy, cost-effective and preferred over a wired-halogen indirect ophthalmoscope.

  17. Effect of light irradiation by light emitting diode on colon cancer cells.

    Science.gov (United States)

    Matsumoto, Noriko; Yoshikawa, Kozo; Shimada, Mitsuo; Kurita, Nobuhiro; Sato, Hirohiko; Iwata, Takashi; Higashijima, Jun; Chikakiyo, Motoya; Nishi, Masaaki; Kashihara, Hideya; Takasu, Chie; Eto, Shohei; Takahashi, Akira; Akutagawa, Masatake; Emoto, Takahiro

    2014-09-01

    Recent studies have demonstrated the efficacy of irradiation from light emitting diodes (LED) for wound healing, anti-inflammation and anticancer therapies. However, little is known about the effects of visible light in colon cancer cells. The purpose of this study was to evaluate the biological response (including gene expression changes) of human colon cancer cells to different wavelengths of LED irradiation. Human colon cancer cells (HT29 or HCT116) were seeded onto laboratory dishes that were then put on LED irradiation equipment with a 465 nm-, 525 nm-, or 635 nm-LED. Irradiation at 15 or 30 mW was performed 10 min/day, each day for 5 days. The cell counting kit8 was then used to measure cell viability. Apoptosis and expression of several mRNAs (caspase, MAPK and autophagy pathway) in HT29 cultures irradiated with 465 nm LED were evaluated via AnnexinV/PI and RT-PCR, respectively. Viability of HT29 and HCT116 cells was lower in 465 nm-LED irradiated cultures than in control cultures, but viability of HT29 cells did not differ between control cultures and 525 nm-LED or 635 nm-LED irradiated cultures. Moreover, the expression of FAS, caspase-3, capase-8, and JUK were significantly higher in 465 nm-LED irradiated cultures than in control cultures, and expression of ERK1/2 and LC3 was lower in blue-irradiated cells. LED irradiation at 465 nm inhibited the proliferation of HT29 cells and of HCT116 cells. Notably, LED irradiation at 465 nm promoted apoptosis inHT29 cultures via the extrinsic apoptosis pathway and the MAPK pathway. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  18. Light scattering studies of irradiated {kappa}- and {iota}-carrageenan

    Energy Technology Data Exchange (ETDEWEB)

    Abad, L.V. [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan) and Philippine Nuclear Research Institute, Commonwealth Ave., Diliman, Quezon City (Philippines)]. E-mail: lvabad@pnri.dost.gov.ph; Nasimova, I.R. [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan); Physics Department, Moscow State University, Moscow 119992 (Russian Federation); Aranilla, C.T. [Philippine Nuclear Research Institute, Commonwealth Ave., Diliman, Quezon City (Philippines); Shibayama, M. [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, 106-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan)]. E-mail: sibayama@issp.u-tokyo.ac.jp

    2005-05-01

    The relationships between the molecular weight (Mw) and the characteristic decay time distribution function G({gamma}) of irradiated kappa ({kappa}-) and iota ({iota}-) carrageenan were studied by static and dynamic light scattering (DLS). Mw and the characteristic decay time ({gamma}{sup -1}) are both steep decreasing exponential function with radiation dose. The dynamic behavior of irradiated {iota}-carrageenan was compared to irradiated {kappa}-carrageenan by DLS. The intensity correlation function of both carrageenans shifted towards shorter relaxation times with increasing radiation dose. Irradiated {iota}-carrageenan like {kappa}-carrageenan exhibits power law behavior at 0-50 kGy (at 0.05-0.1M KCl) indicating similar gelation behaviors. The temperature at which transition from coil to helix takes place (conformational transition temperature) decreases with increasing irradiation dose. A new faster relaxation mode appears at around 0.1-1 ms for both carrageenans between 100 and 150 kGy. Maximum peak height for this mode is at 100 kGy which corresponds to the optimum biological activity of {kappa}- and {iota}-carrageenan.

  19. Light ion irradiation for unfavorable soft tissue sarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Linstadt, D.; Castro, J.R.; Phillips, T.L.; Petti, P.L.; Collier, J.M.; Daftari, I.; Schoethaler, R.; Rayner, A.

    1990-09-01

    Between 1978 and 1989, 32 patients with unfavorable soft tissue sarcoma underwent light ion (helium, neon) irradiation with curative intent at Lawrence Berkeley Laboratory. The tumors were located in the trunk in 22 patients and head and neck in 10. Macroscopic tumor was present in 22 at the time of irradiation. Two patients had tumors apparently induced by previous therapeutic irradiation. Follow-up times for surviving patients ranged from 4 to 121 months (median 27 months). The overall 3-year actuarial local control rate was 62%; the corresponding survival rate was 50%. The 3-year actuarial control rate for patients irradiated with macroscopic tumors was 48%, while none of the patients with microscopic disease developed local recurrence (100%). The corresponding 3-year actuarial survival rates were 40% (macroscopic) and 78% (microscopic). Patients with retroperitoneal sarcoma did notably well; the local control rate and survival rate were 64% and 62%, respectively. Complications were acceptable; there were no radiation related deaths, while two patients (6%) required operations to correct significant radiation-related injuries. These results appear promising compared to those achieved by low -LET irradiation, and suggest that this technique merits further investigation.

  20. Light Penetration and Light-Intensity in Sandy Marine-Sediments Measured with Irradiance and Scalar Irradiance Fiberoptic Microprobes Rid A-1977-2009

    DEFF Research Database (Denmark)

    KUHL, M.; LASSEN, C.; JØRGENSEN, BB

    1994-01-01

    of downwelling irradiance underestimated the total quantum flux available, i.e. scalar irradiance, by > 100 % throughout the sediment. Attenuation coefficents of scalar irradiance, downwelling irradiance and upwelling irradiance were, however, similar in deeper sediment layers where the light field became more...... surface ranging from 180 % of incident collimated light in the coarsest sediment (250 to 500 mum grain size) up to 280 % in the finest sediment ( 1 mm in the coarsest sediments. Below 1 mm, light was attenuated exponentially with depth in all sediments. Light attenuation coefficients decreased...... with increasing particle size, and infrared light penetrated deeper than visible light in all sediments. Attenuation spectra of scalar irradiance exhibited the strongest attenuation at 450 to 500 ran, and a continuous decrease in attenuation coefficent towards the longer wavelengths was observed. Measurements...

  1. A mechanism of cell apoptosis by light irradiation

    Science.gov (United States)

    Xing, Da; Gao, Xuejuan; Wang, Fang

    2006-02-01

    Light irradiation can modulate various biological processes. For instance, low-power laser irradiation (LPLI) can induce cell proliferation and differentiation. It has been used to treat diseases of regeneration limitation and to promote wound healing. The biological mechanism of light irradiation remains unclear. Our previous studies have shown that low fluence LPLI induced the proliferation of human lung adenocarcinoma cells (ASTC-a-1) through PKC channel, while high fluence LPLI induced caspase-3 activation and cell apoptosis. The mechanisms of the initiation and regulation of apoptosis are complex and diverse. There are two main pathways to initiate and regulate cell apoptosis, one is the death receptor pathway (receptor/caspase-8/caspase-3), and the other is the mitochondria pathway (mitochondria/ caspase-9/caspase-3). Using fluorescent imaging techniques, we observed a temporal sequence of events during apoptosis induced by high fluence LPLI and PDT. Both the high fluence LPLI and PDT triggers mitochondrial ROS production resulting in dissipation of ΔΨ m and activation of caspase-3. Our results also show the two treatments do not activate caspase-8. These results suggest that caspase-3 activation induced by high fluence LPLI or PDT is initiated directly from mitochondria ROS generation and dissipation of ΔΨ m, and independent of the cell death pathway involving caspase-8 activation. Because the progression of the apoptosis induced by high fluence LPLI is the same as that of PDT, we concluded that light is absorbed directly either by endogenous porphyrins or by the cytochromes in mitochondrion, resulting in initial ROS generation. During light irradiation induced apoptosis, apoptotic signals are initiated from mitochondrial ROS production due to photosensitization.

  2. Physical processes in azobenzene polymers on irradiation with polarized light

    DEFF Research Database (Denmark)

    Holme, N.C.R.; Nikolova, L.; Norris, T.B.

    1999-01-01

    . A transition route based on experimental results for the theoretically calculated energy level scheme is proposed. Physical observations of surface relief in thin films of azobenzene polymers when irradiated with polarized light are reported. These include two beam polarization holographic observations...... and single beam transmission measurements through a mask, followed by atomic force microscope and profiler investigations. It is concluded that none of the prevalent theories can explain all the observed facts....

  3. Clinical long-term success of contemporary nano-filled resin composites in class I and II restorations cured by LED or halogen light.

    Science.gov (United States)

    Pflaum, Torsten; Kranz, Stefan; Montag, Regina; Güntsch, Arndt; Völpel, Andrea; Mills, Robin; Jandt, Klaus; Sigusch, Bernd

    2017-10-28

    The use of LED light-curing units (LED LCUs) for polymerising resin-based composite restorations has become widespread throughout dentistry. Unfortunately, there is a paucity of clinical longitudinal studies that evaluate the comparative efficacy of LED-based polymerisation in direct posterior composite restorations. The aim of the present study was to investigate the performance of class I and II resin composite restorations for two successful composite restorative materials cured with LED versus halogen LCUs. One hundred restorations were placed using the nano-filled composites Grandio® or Filtek™ Supremé. The following test groups were established: LED-Grandio® n = 23 (LG), LED-Filtek™ Supremé n = 21 (LS). As controls were used: Halogen-Grandio® n = 28 (HG), Halogen-Filtek™ Supremé n = 28 (HS). All restorations were evaluated according to the clinical criteria of the CPM index (C-criteria) at baseline and after 6, 12 and 36 months. After 12 and 36 months, there were no significant differences between restorations polymerised with LED or halogen light. At the end of the study, 97% of the restorations showed sufficient results regardless of the employed LCU or composite. Globally, after 36 months, 56% of all restorations were assessed with code 0 (excellent) and 41% with code 1 (acceptable). In detail, excellent results (code 0) among the criteria surface quality; marginal integrity and marginal discoloration were assigned in 72, 70 and 69%. For the current limitations in the clinical trial design, the results showed that LED-polymerisation is appropriate to ensure clinical success of direct posterior resin composite restorations in a range of 3 years. The choice of LCU has no significant influence on the clinical performance of posterior direct resin composite restorations within 3 years of wear.

  4. Partially photodegradable hybrid hydrogels with elasticity tunable by light irradiation.

    Science.gov (United States)

    Yanagawa, Fumiki; Mizutani, Takeomi; Sugiura, Shinji; Takagi, Toshiyuki; Sumaru, Kimio; Kanamori, Toshiyuki

    2015-02-01

    This paper reports a simple technique to synthesize elasticity tunable hybrid hydrogels using photocleavable (N-hydroxysuccinimide terminated photocleavable tetra-arm poly(ethylene glycol); NHS-PC-4armPEG) and non-photocleavable (N-hydroxysuccinimide terminated tetra-arm poly(ethylene glycol); NHS-4armPEG) activated-ester type crosslinkers. Partially photodegradable hybrid hydrogels were synthesized by reacting the crosslinker mixture with amino-terminated tetra-arm poly(ethylene glycol) (amino-4armPEG). The photocleavable crosslinks are cleaved by irradiating light while the non-photocleavable crosslinks remain intact, resulting in decreased elasticity. We demonstrate that hydrogel elasticity can be controlled by adjusting the ratio of photocleavable NHS-PC-4armPEG and non-photocleavable NHS-4armPEG, and by varying the light exposure energy. We also show how micropatterned elasticity can be obtained in the hydrogels by irradiating with micropatterned light. These techniques could provide a novel platform to tailor the elasticity of hydrogels with microscale precision for biological studies in the near future. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Effectiveness Of UVC Lights Irradiation To Improve Energy Saving

    Directory of Open Access Journals (Sweden)

    Sameer A. Bilal

    2015-08-01

    Full Text Available HVAC Heating Ventilation and Air conditioning is the largest consumer of energy in commercial and industrial buildings. HVAC systems account for an approximated 50 of energy use in buildings. The sources of contamination and odour comes from the growth of bacteria mold and fungus that accumulate and develop on wet surfaces of HVAC coils and drain pans causing respiratory infection cough tight chest and wheezing. Besides the effects on human health Fungal contamination that adheres to the fins of cooling coil of air handling unit AHU cause a significant increase in pressure drop across the coil and decrease in heat exchange efficiency which Leeds to loss of cooling capacity and additional energy use. To prevent the fungal and microorganism growth on the cooling coil and drain pan of HVAC systems many studies conducted but not all these solutions were sufficient to remove microbial organism from the HVAC 100 . The UV-C light options through a process known as UVGI Ultraviolet germicidal irradiation is a technology showed a significant impact to produce clean air and improve indoor air quality 16. UVGI lights produce short wavelength light kills microorganisms including viruses bacteria mold and many other fungi by disrupting their DNA. The effectiveness of UVGI installed inside HVAC systems depends on many factors and the application Methods in HVAC systems. A few studies showed whether the use of UVGI results in energy saving. The objective of this study is to find the effect of fungal growth on the cooling coil surface by using field measurements at actual operating conditions of heat transfer and air flow for a non-irradiated coil in comparison to irradiated coil .Hence evaluate if there would be an enthalpy change at the coil and document the effectiveness of UVGI coil cleaning on restoring cooling capacity and save energy.

  6. Comparison of microleakages of photo-cured composites using three different light sources: halogen lamp, LED and argon laser: an in vitro study.

    Science.gov (United States)

    Tielemans, M; Compere, Ph; Geerts, S O; Lamy, M; Limme, M; De Moor, R J G; Delmé, K I M; Bertrand, M F; Rompen, E; Nammour, S

    2009-01-01

    In this study, we compared the microleakage of composite fillings cured with halogen bulb, LED and argon ion laser (488 nm). Twenty-four extracted human molars were divided randomly in three groups. Six cavities were prepared on the coronal part of each tooth. Standard cavities (1.7 x 2 mm) were prepared. Cavities were acid etched, sealed with Scotch Bond 1 and filled by a hybrid composite. Cavities were exposed to one light source, thermocycled and immersed in a 2% methylene blue dye solution. Dye penetration in the leakage of cavities was recorded using a digital optical microscope. Mean values of percentage of dye penetrations in microleakages of cavities were 49.303 +/- 5.178% for cavities cured with LED, 44.486 +/- 6.075% with halogen bulb and 36.647 +/- 5.936% for those cured by argon laser. Statistically significant difference exists between cavities cured by halogen vs LED (P LED vs laser (P < 0.001). The lowest microleakage was observed in the cavities and composites cured with argon ion laser.

  7. Electrical properties of SiO2-based graphene under monochromatic visible light irradiation

    Science.gov (United States)

    Li, Xiangdi; Liu, Xianming; Cao, Xueying; Zhang, Peng; Lei, Xiaohua; Chen, Weimin

    2017-08-01

    The purpose of this study is to investigate the electrical properties of graphene transparent conductive film under visible light irradiation. Sample in the study is chemical vapor deposition (CVD) growth graphene on the surface of copper foils and then transferred to the SiO2 substrate. Three monochromatic visible lights with wavelength of 635nm, 520nm and 450nm representing red (R), green (G) and blue (B) lights are used as irradiation sources. Results show that the graphene resistances increase slowly under light irradiation with all the three different wavelengths, while decrease slowly after the light is switched off. Light irradiation with higher power density will induce larger relative resistance change. When graphene is irradiated at the same density, blue light irradiation may result in the largest resistance change.

  8. Photocatalytic Degradation of Thiram (Fungicides under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Sanjay R. Thakare

    2005-01-01

    Full Text Available Pesticides in the different form are toxic to the environment and removal of its form the various sources is a difficult task. The thiram undergoes photocatalytic degradation under visible light when prepared TiO2∼PVA polymer composite was used as a photocatalyst. The data represent that prepared TiO2∼PVA polymer composite is a more efficient photocatalyst than the neat TiO2. Photocatalytic efficiency of prepared TiO2∼PVA polymer composite was measured in term of no adsorption of pollutant, higher degradation rate and act as a photocatalyst under visible light irradiation. 150 minutes are required for the complete degradation of the thiram. The end products of photocatalytic degradation of thiram are CO2, nitrate and sulphate.

  9. Large area inkjet printing for organic photovoltaics and organic light emitting diodes using non-halogenated ink formulations

    NARCIS (Netherlands)

    Eggenhuisen, T.M.; Coenen, M.J.J.; Slaats, M.W.L.; Groen, W.A.

    2014-01-01

    The transfer of laboratory scale solution processing of organic electronics to large area roll-to-roll production requires the use of up-scalable deposition techniques. Furthermore, industrial production demands the omission of halogenated and other harmful solvents. Here, the authors discuss large

  10. Data acquisition system for light-ion irradiation creep experiment.

    Energy Technology Data Exchange (ETDEWEB)

    Hendrick, P.L.; Whitaker, T.J.

    1979-07-01

    Software was developed for a PDP11V/03-based data acquisition system to support the Light-Ion Irradiation Creep Experiment installed at the University of Washington Tandem Van de Graaff Accelerator. The software consists of a real-time data acquisition and storage program, DAC04, written in assembly language. This program provides for the acquisition of up to 30 chennels at 100 Hz, data averaging before storage on disk, alarming, data table display, and automatic disk switching. All analog data are acquired via an analog-to-digital converter subsystem having a resolution of 14 bits, a maximum throughput of 20 kHz, and an overall system accuracy of +-0.01%. These specifications are considered essential for the long-term measurement of irradiation creep strains and temperatures during the light-ion bombardment of irradiation creep specimens. The software package developed also contains a collection of FORTRAN programs designed to monitor a test while in progress. These programs use the foreground/background feature of the RT-11 operating system. The background programs provide a variety of services. The program, GRAFTR, allows transient data (i.e., prior to averaging) to be graphed at the graphics terminal. The program, GRAFAV, allows averaged data to be read from disk and displayed graphically at the terminal. The program, TYPAV, reads averaged data from disk and displays it at the terminal in tabular form. Other programs allow text messages to be written to disk, read from disk, and allow access to DAC04 initialization data. 5 figures, 18 tables.

  11. Effect of light-emitting diode and halogen light curing on the micro-hardness of dental composite and resin-modified glass ionomer cement: An in vitro study

    Directory of Open Access Journals (Sweden)

    M Bhalla

    2012-01-01

    Full Text Available Aims : This in vitro study was conducted to evaluate and compare the micro-hardness of composite resin and resin-modified glass ionomer cement using light-emitting diode (LED and halogen curing and also to inter-compare the effect of LED and halogen curing. Materials and Methods : The study sample comprised of 4 stainless steel plates with a thickness of 2 mm. For these stainless steel plates, holes were made to a diameter of 3 mm. The samples were divided into 4 groups of 8 each and labeled as group I, group II, group III, group IV, thus making provision for the two different modes of light exposure. In each group, the hole was restored with its respective restorative material and cured with light-curing unit according to manufacturer instructions. The results were statistically analyzed using Mann-Whitney test. Results and conclusion: It was concluded that the curing efficacy of the LED lamp was comparable to that of conventional halogen lamp, even with a 50% reduction in cure time, and resin composite (Filtek Z-250 presented the highest hardness values, whereas complete hardening of resin-modified glass ionomer cement (RMGIC (Vitremer was observed because of its self-curing system even after the removal of light source.

  12. [Dermatologic risks of quartz-halogen lamps].

    Science.gov (United States)

    Cesarini, J P; Muel, B

    1992-01-01

    Halogene sources are used increasingly in general illumination. Their quartz envelop is technically necessary, but presents the disadvantage of to letting the emitted UVA, UVB and UVC go through. Originally used as in indirect lighting, they have been introduced as desk-top lamps, without filter. We have proceeded to the verification of their output with a spectrophotometer calibrated by actinometry and we have calculated their relative erythemal efficacy according to the Parrish's action spectrum for human erythema. We found that, at 10 cm from the human skin, the irradiance was able to induce a minimal erythema in about 10 minutes on clear back skin. At working distance (50 cm), a barely perceptible erythema could be observed on the back of the hands after 8 consecutive hours working. We also found that sunburn cells were present in the skin sensitized with a potent phototoxic agent (8-methoxypsoralen) applied 15 minutes before a 4-6 minutes irradiation with the halogen source (at 20 cm), thus, indicating a potential risk for local phototoxicity and photoallergy. The cumulative doses per year, for 4 hours exposure per day, five days a week, reaches 125 minimal erythemal doses, equivalent to the average yearly exposure of individuals for work and leisure. If one assumes that this regimen is maintained for 30 years, the risk for induction of skin cancers on the dorsal aspect of the hands and the forearms, may be increased by a 3.4 factor, according to the widely accepted previsional models.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Conductive stability of graphene on PET and glass substrates under blue light irradiation

    Science.gov (United States)

    Cao, Xueying; Liu, Xianming; Li, Xiangdi; Lei, Xiaohua; Chen, Weimin

    2018-01-01

    Electrical properties of graphene transparent conductive film under visible light irradiation are investigated. The CVD-grown graphene on Polyethylene Terephthalate (PET) and glass substrates for flexible and rigid touch screen display application are chosen for research. The resistances of graphene with and without gold trichloride (AuCl3) doping are measured in vacuum and atmosphere environment under blue light irradiation. Results show that the conductivities of all samples change slowly under light irradiation. The change rate and degree are related to the substrate material, doping, environment and lighting power. Graphene on flexible PET substrate is more stable than that on rigid glass substrate. Doping can improve the electrical conductivity but induce instability under light irradiation. Finally, the main reason resulting in the graphene resistance slowly increasing under blue light irradiation is analyzed.

  14. Elemental Boron for Efficient Carbon Dioxide Reduction under Light Irradiation.

    Science.gov (United States)

    Liu, Guigao; Meng, Xianguang; Zhang, Huabin; Zhao, Guixia; Pang, Hong; Wang, Tao; Li, Peng; Kako, Tetsuya; Ye, Jinhua

    2017-05-08

    The photoreduction of CO2 is attractive for the production of renewable fuels and the mitigation of global warming. Herein, we report an efficient method for CO2 reduction over elemental boron catalysts in the presence of only water and light irradiation through a photothermocatalytic process. Owing to its high solar-light absorption and effective photothermal conversion, the illuminated boron catalyst experiences remarkable self-heating. This process favors CO2 activation and also induces localized boron hydrolysis to in situ produce H2 as an active proton source and electron donor for CO2 reduction as well as boron oxides as promoters of CO2 adsorption. These synergistic effects, in combination with the unique catalytic properties of boron, are proposed to account for the efficiency of the CO2 reduction. This study highlights the promise of photothermocatalytic strategies for CO2 conversion and also opens new avenues towards the development of related solar-energy utilization schemes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. The effect of green laser light irradiation on whole blood platelets.

    Science.gov (United States)

    Gresner, P; Watała, C; Sikurová, L

    2005-04-04

    Laser light irradiation is assumed to have biostimulating effect in various cell types. However, there is still a lack of information concerning response of blood platelets to laser light irradiation. In our study we used flow cytometry to monitor the effect of a green Nd-YAG laser (532 nm, 30 mW) irradiation on platelet activation and the expression of activated GPIIbIIIa glycoprotein complex (fibrinogen receptor) of whole blood platelets stained with fluorolabelled monoclonal antibody PAC-1. Also the formation of platelet microparticles and aggregates in a population of whole blood platelets following such irradiation was evaluated. Effects of laser light on platelet activation and reactivity were significant over a wide range of applied energies (plaser light energies (18 and 54 J) increased platelet activation, the irradiation with a high-energy laser light (108 J) resulted in depressed platelet reactivity and attenuated platelet response to activators. In addition, laser light irradiation had significant influence on the formation of platelet microparticles in either resting (plaser light irradiation significantly increased the formation of platelet aggregates both in resting (plaser light irradiation of blood platelets can trigger signal transduction, leading to platelet activation, as well as the gradual loss of natural platelet reactivity and platelets' ability to respond to activating agents.

  16. White light emitting diode as potential replacement of tungsten-halogen lamp for visible spectroscopy system: a case study in the measurement of mango qualities

    Science.gov (United States)

    Chiong, W. L.; Omar, A. F.

    2017-07-01

    Non-destructive technique based on visible (VIS) spectroscopy using light emitting diode (LED) as lighting was used for evaluation of the internal quality of mango fruit. The objective of this study was to investigate feasibility of white LED as lighting in spectroscopic instrumentation to predict the acidity and soluble solids content of intact Sala Mango. The reflectance spectra of the mango samples were obtained and measured in the visible range (400-700 nm) using VIS spectroscopy illuminated under different white LEDs and tungsten-halogen lamp (pro lamp). Regression models were developed by multiple linear regression to establish the relationship between spectra and internal quality. Direct calibration transfer procedure was then applied between master and slave lighting to check on the acidity prediction results after transfer. Determination of mango acidity under white LED lighting was successfully performed through VIS spectroscopy using multiple linear regression but otherwise for soluble solids content. Satisfactory results were obtained for calibration transfer between LEDs with different correlated colour temperature indicated this technique was successfully used in spectroscopy measurement between two similar light sources in prediction of internal quality of mango.

  17. Productivity of Chlorella sorokiniana in a short light-path (SLP) panel photobioreactor under high irradiance

    NARCIS (Netherlands)

    Cuaresma, M.; Janssen, M.G.J.; Vilchez, C.; Wijffels, R.H.

    2009-01-01

    Maximal productivity of a 14 mm light-path panel photobioreactor under high irradiance was determined. Under continuous illumination of 2,100 µmol photons m-2 s-1 with red light emitting diodes (LEDs) the effect of dilution rate on photobioreactor productivity was studied. The light intensity used

  18. Microdischarge Array Flexible Light Source for High-Efficiency Irradiation of Spaced-Based Crops Project

    Data.gov (United States)

    National Aeronautics and Space Administration — It is desirable to develop a high-efficiency lighting source for large-area irradiation of space-based crops. The key requirements for such a system include high...

  19. Effect of short curing times with a high-intensity light-emitting diode or high-power halogen on shear bond strength of metal brackets before and after thermocycling.

    Science.gov (United States)

    Cerekja, Erion; Cakirer, Banu

    2011-05-01

    To test the hypothesis that short curing times using a high-intensity light-emitting diode (LED) or high-power halogen are not associated with compromised shear bond strength (SBS) of metal brackets before and after thermocycling. Two hundred forty extracted human premolar teeth were divided into six groups of 40 each. Metal brackets were bonded using a light-cured composite (Transbond XT). In group 1 a conventional halogen light (Hilux) was used for 40 seconds. In groups 2, 3, and 4 a high-power halogen light (Swiss Master) was used for 2, 3, and 6 seconds, respectively. In groups 5 and 6 a high-intensity LED (Bluephase) was used for 10 and 20 seconds, respectively. After bonding, half of the specimens in each group were thermocycled, and all specimens were tested for SBS. After debonding, the bracket bases and the enamel surfaces were scored according to the Adhesive Remnant Index. Two-way analysis of variance detected significant differences in SBS values with respect to curing method (type of light-curing unit and curing time) (P  =  .0001) and thermocycling (P  =  .01). Tukey post hoc analysis showed that with or without thermocycling the mean SBS values of groups 1, 4, 5, and 6 were not significantly different, whereas group 2 showed the lowest SBS values. The predominant failure site for groups 2 and 3 was between the bracket and the adhesive and for groups 4, 5, 6 it was at the tooth/adhesive interface. Curing time can be reduced to 6 seconds with high-power halogen light and to 10 seconds with high-intensity LED without compromising in vitro SBS of metal brackets.

  20. Influence of UV irradiation on the blue and red light photoinduced processes in azobenzene polyesters

    DEFF Research Database (Denmark)

    Rodríguez, F.J.; Sánchez, C.; Villacampa, B.

    2004-01-01

    Birefringence induced in a series of liquid crystalline side-chain azobenzene polyesters with different substituent groups was investigated under irradiation with 488 and 633 nm linearly polarized lights. Two different initial conditions have been used: the effect of a previous irradiation with UV...... light that yields the films into the isotropic state at room temperature (RT) was compared with the quenching from temperatures above the isotropic transition temperature Ti. UV–visible spectra of the thermally quenched films show the presence of aggregates when measured at RT. We have found that UV...... light irradiation creates a high concentration of cis isomers and breaks the aggregates, but they are formed again after a few days in dark at RT. Orientation of the chromophores perpendicular to the polarization of the 488 nm light and parallel to the polarization of the 633 nm light was confirmed...

  1. Blue-light irradiation regulates proliferation and differentiation in human skin cells.

    Science.gov (United States)

    Liebmann, Joerg; Born, Matthias; Kolb-Bachofen, Victoria

    2010-01-01

    Sunlight influences the physiology of the human skin in beneficial as well as harmful ways, as has been shown for UV light. However, little is known about the effects of other wavelengths of solar irradiation. In this study we irradiated human keratinocytes and skin-derived endothelial cells with light-emitting-diode devices of distinct wavelengths to study the effects on cell physiology. We found that light at wavelengths of 632-940 nm has no effect, but irradiation with blue light at 412-426 nm exerts toxic effects at high fluences. Light at 453 nm is nontoxic up to a fluence of 500 J/cm(2). At nontoxic fluences, blue light reduces proliferation dose dependently by up to 50%, which is attributable to differentiation induction as shown by an increase of differentiation markers. Experiments with BSA demonstrate that blue-light irradiation up to 453 nm photolytically generates nitric oxide (NO) from nitrosated proteins, which is known to initiate differentiation in skin cells. Our data provide evidence for a molecular mechanism by which blue light may be effective in treating hyperproliferative skin conditions by reducing proliferation due to the induction of differentiation. We observed a photolytic release of NO from nitrosated proteins, indicating that they are light acceptors and signal transducers up to a wavelength of 453 nm.

  2. Natural genetic variation for acclimation of photosynthetic light use efficiency to growth irradiance in Arabidopsis

    NARCIS (Netherlands)

    Rooijen, van R.; Aarts, M.G.M.; Harbinson, J.

    2015-01-01

    Plants are known to be able to acclimate their photosynthesis to the level of irradiance. Here we present the analysis of natural genetic variation for photosynthetic light use efficiency (FPSII) in response to five light environments among 12 genetically diverse Arabidopsis thaliana accessions. We

  3. [Enhanced visible-light absorbance of nanosized AgI/TiO2 by using calcination combined with light irradiation].

    Science.gov (United States)

    Liang, Zhu; Ni, Jin-Ren

    2009-07-15

    With the aim to enhance visible-light absorbance, calcination combined with light irradiation was used to modify nanosized AgI/TiO2. UV-Vis spectrum curves indicated that the modified sample exhibited an intense absorption in the whole visible light range and a spectrum shifted from 465 nm to 800 nm, and that absorbance at 500 nm was improved three times as much as that of the reported pertinent material. XRD analytic results demonstrated that calcined AgI/TiO2 possessed more rutile phase with reduced band gap from 2.89 eV to 2.81 eV, and that the following xenon-light irradiation further enhanced the relative contents of anatase TiO2, rutile TiO2 and AgI accompanied with produced AgCl phase, leading to the decrease in band gap to 1.55 eV. Formation of AgCl and increases in the relative contents of rutile TiO2 and AgI should take the main responsibilities for the decrease in the band gap and enlargement of visible-light absorbance. Additionally, it was confirmed that only the spectrum absorption of the calcined AgI/TiO2 could be improved by light irradiation, and that ultraviolet light played more role than visible part during the light irradiation. Moreover, it was proposed here that two or more silver halides supported on TiO2 could show more capabilities to stimulate visible-light activation of TiO2.

  4. Heavy ion irradiation effects of polymer film on absorption of light

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Noboru; Seguchi, Tadao [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Arakawa, Tetsuhito

    1997-03-01

    Ion irradiation effects on the absorption of light for three types of polymer films; polyethylene-terephthalate (PET), polyethylene-naphthalate (PEN), and polyether-ether-ketone (PEEK) were investigated by irradiation of heavy ions with Ni{sup 4+}(15MeV), O{sup 6+}(160MeV), and Ar{sup 8+}(175MeV), and compared with electron beams(EB) irradiation. The change of absorption at 400nm by a photometer was almost proportional to total dose for ions and EB. The absorption per absorbed dose was much high in Ni{sup 4+}, but rather small in O{sup 6+} and Ar{sup 8+} irradiation, and the absorption by EB irradiation was accelerated by the temperature of polymer film during irradiation. The beam heating of materials during ion irradiation was assumed, especially for Ni ion irradiation. The heavy ion irradiation effect of polymers was thought to be much affected by the ion beam heating than the linear energy transfer(LET) of radiation source. (author)

  5. Sensitivity to Ethephon Degreening Treatment Is Altered by Blue LED Light Irradiation in Mandarin Fruit.

    Science.gov (United States)

    Deng, Lili; Yuan, Ziyi; Xie, Jiao; Yao, Shixiang; Zeng, Kaifang

    2017-08-02

    Although citrus fruits are not climacteric, exogenous ethylene is widely used in the degreening treatment of citrus fruits. Irradiation with blue light-emitting diode (LED) light (450 nm) for 10 h can promote the formation of good coloration of ethephon-degreened fruit. This study evaluated the effect of blue LED light irradiation on the pigments contents of ethephon-degreened fruit and evaluated whether the blue LED light irradiation could influence the sensitivity of mandarin fruit to ethylene. The results indicated that blue light can accelerate the color change of ethephon-degreened fruit, accompanied by changes in plastid ultrastructure and chlorophyll and carotenoid contents. Ethephon-induced expressions of CitACS1, CitACO, CitETR1, CitEIN2, CitEIL1, and CitERF2 were enhanced by blue LED light irradiation, which increased the sensitivity to ethylene in ethephon-degreened fruits. These results indicate that blue LED light-induced changes in sensitivity to ethylene in mandarin fruit may be responsible for the improved coloration of ethephon-degreened mandarin fruits.

  6. Photochemical decomposition of perfluorooctanoic acid in aqueous periodate with VUV and UV light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cao, M.H.; Wang, B.B.; Yu, H.S.; Wang, L.L.; Yuan, S.H. [Environmental Science Research Institution, College of Environment Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, J., E-mail: chenjing@mail.hust.edu.cn [Environmental Science Research Institution, College of Environment Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2010-07-15

    The photochemical decomposition of perfluorooctanoic acid (PFOA) in aqueous periodate (IO{sub 4}{sup -}) was investigated under two types of low-pressure mercury lamps: one emits at 254 nm light (UV light) and the other emits both 254 nm and 185 nm light (VUV light). PFOA decomposed efficiently under VUV light irradiation while it decomposed poorly under UV light irradiation. The addition of IO{sub 4}{sup -} significantly increased the rate of decomposition and defluorination of PFOA irradiated with UV light whereas it decreased both processes under VUV irradiation. Reactive radical (IO{sub 3}{center_dot}) generated by photolysis of IO{sub 4}{sup -} initiated the oxidation of PFOA in UV process. Aquated electrons (e{sub aq}{sup -}), generated from water homolysis, scavenged IO{sub 4}{sup -} resulting in decrease of reactive radical species production and PFOA decomposition. The shorter-chain perfluorocarboxylic acids (PFCAs) formed in a stepwise manner from long-chain PFCAs.

  7. Light-induced fading of the PSL signal from irradiated herbs and spices

    Energy Technology Data Exchange (ETDEWEB)

    Alberti, A. [ISOF-CNR, Via P. Gobetti 101, 40129 Bologna (Italy); Corda, U. [ISOF-CNR, Via P. Gobetti 101, 40129 Bologna (Italy); Fuochi, P. [ISOF-CNR, Via P. Gobetti 101, 40129 Bologna (Italy)]. E-mail: fuochi@isof.cnr.it; Bortolin, E. [Istituto Superiore di Sanita, Viale Regina Elena 299, 00161 Rome (Italy); Calicchia, A. [Istituto Superiore di Sanita, Viale Regina Elena 299, 00161 Rome (Italy); Onori, S. [Istituto Superiore di Sanita, Viale Regina Elena 299, 00161 Rome (Italy)

    2007-08-15

    Reliability of the photo-stimulated luminescence (PSL) technique, as screening method for irradiated food identification, has been tested with three kinds of herbs and spices (oregano, red pepper and fennel), prepared in two different ways (granular: i.e. seeds and flakes, or powdered), over a long period of storage with different light exposures. The irradiated samples kept in the dark gave always a positive response (the sample is correctly classified as 'irradiated') for the overall examination period. The samples kept under ambient light conditions, in typical commercial glass containers, exhibited a reduction of the PSL signal, more or less pronounced depending on the type of food and packaging. The different PSL response of the irradiated samples is to be related to the quantity and quality of the mineral debris present in the individual food. It was also found that, for the same type of food, the light-induced fading was much stronger for the flaked and seed samples than for the corresponding powder samples, the penetrating capability of light being much more inhibited in powdered than in whole seeds or flaked form samples. The observed light bleaching of the PSL signal in irradiated herbs and spices is of practical relevance since it may lead to false negative classifications.

  8. Enhancement of cell growth rate by light irradiation in the cultivation of Rhodotorula glutinis.

    Science.gov (United States)

    Yen, Hong-Wei; Zhang, Zhiyong

    2011-10-01

    A yeast, Rhodotorula glutinis, is regarded as a potential microbial oil producer, due to its high lipid content. The flask results of this study indicated that irradiation could increase the growth of R. glutinis compared to that of a batch without irradiation. Further 5-l fermenter results confirmed that irradiation could greatly enhance the cells' growth rate and total lipid productivity. The maximum lipid productivity obtained in the fed-batch operation with 3 LED (light emitting diode) lamps was 0.39 g/l h as compared to 0.34 g/l h in the batch with 3 LED lamps and 0.19 g/l h in the batch without irradiation. Conclusively, the irradiation could significantly increase the cells' growth rate, which, in turn, could be applied to the commercialized production of biodiesel from single cell oils. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Classical and melanopsin photoreception in irradiance detection: negative masking of locomotor activity by light.

    Science.gov (United States)

    Thompson, Stewart; Foster, Russell G; Stone, Edwin M; Sheffield, Val C; Mrosovsky, N

    2008-04-01

    Studies in mice lacking either classical or melanopsin photoreception have been useful in describing the photoreceptor contribution to irradiance detection in accessory visual responses. However, application of these findings to irradiance detection in intact animals is problematical because retinal degeneration or manipulation can induce secondary changes in the retina. Among responses dependent on irradiance detection, the suppression of activity by light (negative masking) has had limited study. To further understand the function of classical and melanopsin photoreceptors we studied irradiance and spectral sensitivity of masking by light, primarily in mice with intact retinae. The sensitivity of negative masking was equivalent for medium ( approximately 500 nm) and short wavelengths ( approximately 365 nm) in three strains of wild-type mice, identifying a marked short-wavelength-sensitive-cone input. At medium wavelengths, spectral sensitivity above 500 nm had closest fit to the nomogram for the medium-wavelength-sensitive-cone, but a combined input of cone and melanopsin photoreceptors in wild-type mice seems likely. Under white light a decompression of the irradiance range of masking in C3H rd/rd cl mice, lacking rods and cones, identified a functional deficiency presumably resulting from the absence of classical photoreceptor input. Together the evidence demonstrates a pronounced and sustained classical photoreceptor input to irradiance detection for negative masking, and suggests one role of classical photoreceptor input is to constrain dynamic range.

  10. Bactericidal effects of 310 nm ultraviolet light-emitting diode irradiation on oral bacteria.

    Science.gov (United States)

    Takada, Ayuko; Matsushita, Kenji; Horioka, Satoru; Furuichi, Yasushi; Sumi, Yasunori

    2017-06-06

    Ultraviolet (UV) light is used for phototherapy in dermatology, and UVB light (around 310 nm) is effective for treatment of psoriasis and atopic dermatitis. In addition, it is known that UVC light (around 265 nm) has a bactericidal effect, but little is known about the bactericidal effect of UVB light. In this study, we examined the bactericidal effects of UVB-light emitting diode (LED) irradiation on oral bacteria to explore the possibility of using a 310 nm UVB-LED irradiation device for treatment of oral infectious diseases. We prepared a UVB (310 nm) LED device for intraoral use to examine bactericidal effects on Streptococcus mutans, Streptococcus sauguinis, Porphyromonas gingivalis, and Fusobacterium nucleatum and also to examine the cytotoxicity to a human oral epithelial cell line (Ca9-22). We also examined the production of nitric oxide and hydrogen peroxide from Ca9-22 cells after irradiation with UVB-LED light. Irradiation with the 310 nm UVB-LED at 105 mJ/cm(2) showed 30-50% bactericidal activity to oral bacteria, though 17.1 mJ/cm(2) irradiation with the 265 nm UVC-LED completely killed the bacteria. Ca9-22 cells were strongly injured by irradiation with the 265 nm UVC-LED but were not harmed by irradiation with the 310 nm UVB-LED. Nitric oxide and hydrogen peroxide were produced by Ca9-22 cells with irradiation using the 310 nm UVB-LED. P. gingivalis was killed by applying small amounts of those reactive oxygen species (ROS) in culture, but other bacteria showed low sensitivity to the ROS. Narrowband UVB-LED irradiation exhibited a weak bactericidal effect on oral bacteria but showed low toxicity to gingival epithelial cells. Its irradiation also induces the production of ROS from oral epithelial cells and may enhance bactericidal activity to specific periodontopathic bacteria. It may be useful as a new adjunctive therapy for periodontitis.

  11. Photocatalytic dye degradation with copper–titanium dioxide nanocomposites under sunlight and visible light irradiation

    Science.gov (United States)

    Qayyum Khan, Abdul; Yuan, Shuai; Niu, Sheng; Liu, Fengjiang; Feng, Guang; Jiang, Mengci; Zeng, Heping

    2018-01-01

    Photocatalytic methalyne blue dye degradation was carried out with copper (Cu)–titanium dioxide (TiO2) nanocomposites under sunlight and visible light irradiation. The Cu–TiO2 nanocomposites were fabricated via femtosecond laser ablation of pressed targets in water. The current method provides a facile route for Cu–TiO2 nanocomposites preparation, which is free from impurities on the catalysts surface. The Cu–TiO2 nanocomposites (with Cu content of 5 wt%) have shown 3 folds faster dye degradation kinetics compared with TiO2 nanoparticles under sunlight irradiation. While under visible light irradiation, the same nanocomposites exhibited 2.6 folds faster kinetics compared with TiO2 nanoparticles. The faster light harvesting efficiency of the catalysts is attributed to more hydroxyl radical generation.

  12. Effect of light intensity and irradiation time on the polymerization process of a dental composite resin

    Directory of Open Access Journals (Sweden)

    Discacciati José Augusto César

    2004-01-01

    Full Text Available Polymerization shrinkage is a critical factor affecting the longevity and acceptability of dental composite resins. The aim of this work was to evaluate the effect of light intensity and irradiation time on the polymerization process of a photo cured dental composite resin by measuring the Vickers hardness number (VHN and the volumetric polymerization shrinkage. Samples were prepared using a dental manual light-curing unit. The samples were submitted to irradiation times of 5, 10, 20 and 40 s, using 200 and 400 mW.cm-2 light intensities. Vickers hardness number was obtained at four different moments after photoactivation (immediate, 1 h, 24 h and 168 h. After this, volumetric polymerization shrinkage values were obtained through a specific density method. The values were analyzed by ANOVA and Duncan's (p = 0.05. Results showed increase in hardness values from the immediate reading to 1 h and 24 h readings. After 24 h no changes were observed regardless the light intensities or activation times. The hardness values were always smaller for the 200 mW.cm-2 light intensity, except for the 40 s irradiation time. No significant differences were detected in volumetric polymerization shrinkage considering the light intensity (p = 0.539 and the activation time (p = 0.637 factors. In conclusion the polymerization of the material does not terminate immediately after photoactivation and the increase of irradiation time can compensate a lower light intensity. Different combinations between light intensity and irradiation time, i.e., different amounts of energy given to the system, have not affected the polymerization shrinkage.

  13. Identifying counterfeit cigarette packs using ultraviolet irradiation and light microscopy.

    Science.gov (United States)

    Kurti, Marin; He, Yi; von Lampe, Klaus; Li, Yanlei

    2017-01-01

    Develop a method that yields high rates of sensitivity and specificity for determination of counterfeit cigarette packs for three popular brands: Newport, Marlboro ('Red') and Marlboro Gold. Using systematic keyword searches, we identified industry documents from the University of California, San Francisco's Legacy Tobacco Documents Library that describe the use of ultraviolet (UV) irradiation and close examination of printing quality to distinguish between counterfeit and genuine cigarette packs. Guided by these documents, we identified six markers for counterfeit cigarettes across three popular brands using counterfeit cigarette packs (N=68) seized by law enforcement agencies in the USA. We assessed the diagnostic test accuracy of these markers and tested it against genuine packs (N=22) using receiver operating characteristic curves analysis. We find that counterfeit cigarette packs fluoresce to long-wave UV irradiation and display poor printing quality. The optimal cut-off value varies among the three brands. For example, counterfeit Newport and Marlboro packaging can be reliably classified with two of six characteristics, while Marlboro Gold requires four. Researchers who conduct littered pack and pack swap studies are urged to include this method to assess the share of counterfeit cigarettes, and compare the result against tobacco industry figures. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  14. Therapeutic effect of turquoise versus blue light with equal irradiance in preterm infants with jaundice.

    Science.gov (United States)

    Ebbesen, Finn; Madsen, Poul; Støvring, Søren; Hundborg, Heidi; Agati, Giovanni

    2007-06-01

    To compare the efficiency of turquoise light with that of TL52 blue in treatment of preterm infants with jaundice at the same level of body irradiance. Infants with gestational age 28-37 weeks and non-haemolytic hyperbilirubinemia were treated for 24 h with either turquoise light (OSRAM L18W/860 fluorescent lamps) or blue light (Philips TL20W/52 fluorescent lamps). The concentrations of serum total bilirubin and bilirubin isomers were measured by the Vitros routine method and by HPLC, respectively. The decrease in serum concentrations of total bilirubin, total bilirubin isomers and the toxic Z,Z-bilirubin was greatest for infants treated with turquoise light. Further, the increase in Z,E-bilirubin was smaller and there was a trend towards a higher rise in E,Z-bilirubin. Turquoise light has a greater bilirubin reducing effect than TL52 blue light with equal irradiance, expressed both by serum total bilirubin, total bilirubin isomers and Z,Z-bilirubin, i.e. the turquoise spectral range is more efficient than the blue. This is in accordance with deeper penetration into the skin, lower production of the Z,E-bilirubin and greater production of E,Z-bilirubin and lumirubin, in infants under turquoise light. This suggests, given equal irradiances, that light in the turquoise spectral range is preferable to the TL52 blue in treatment of newborn jaundiced infants.

  15. A Fiberoptic Scalar Irradiance Microsensor - Application for Spectral Light Measurements in Sediments

    DEFF Research Database (Denmark)

    LASSEN, C.; PLOUG, H.; JØRGENSEN, BB

    1992-01-01

    The manufacturing of a new spherical fibreoptic microsensor is described. The microsensor measures scalar irradiance, i.e. the spherically integrated light at a point in space. The light collector of the probe was a 70-mu-m diffusing sphere cast on the tip of a 125-mu-m wide optical fibre tapered...... down to 15-20-mu-m diametre. The microsensor had an isotropic (+/- 10%) response from -160-degrees to +160-degrees over the whole spectral range from 400-900 nm in air as well as in water. The microsensor was coupled to a sensitive spectroradiometre and the spectral distribution of scalar irradiance...

  16. Superconcentration of light: circumventing the classical limit to achievable irradiance.

    Science.gov (United States)

    Roth, Stephan; Sheppard, Colin J R; Heintzmann, Rainer

    2016-05-01

    Concentration of light is limited by a fundamental physical principle, which ensures that étendue, the product of area and solid angle, can never decrease in an optical system. In microscopy, many superresolving methods, which can overcome the classical resolution limit, have recently emerged. We propose, and demonstrate experimentally, that it is also possible to circumvent the classical light concentration limit. Actually, most superresolution methods exhibit a common drawback: with respect to the total number of emitted photons, they are less efficient than standard widefield microscopy. Most methods "shave"' the point spread function (PSF) by discarding the disturbing signal from its edge. We show, that in contrast to PSF-shaving, methods related to reassignment microscopy (image scanning microscopy, optical photon reassignment, rescan confocal, instant structured illumination microscopy) concentrate all detected photons in their superresolving images and thereby increase the detected signal per sample area compared to widefield microsopy. We term this behavior superconcentration, as it breaks the classical light concentration limit.

  17. Enhancement of visible light irradiation photocatalytic activity of ...

    Indian Academy of Sciences (India)

    Mohamed Abdel Salam

    2017-09-25

    Sep 25, 2017 ... Yin D and Zhao F 2015 Visible-light-responsive sulfated vanadium-doped TS-1 with hollow structure: Enhanced photocatalytic activity in selective oxidation of cyclo- hexane J. Catal. 330 208. 11. Kim J, Ichikuni N, Hara T and Shimazu S 2016 Study on the selectivity of propane photo-oxidation reaction on.

  18. Mechanical properties and degree of conversion of etch-and-rinse and self-etch adhesive systems cured by a quartz tungsten halogen lamp and a light-emitting diode.

    Science.gov (United States)

    Gaglianone, Lívia Aguilera; Lima, Adriano Fonseca; Gonçalves, Luciano Souza; Cavalcanti, Andrea Nóbrega; Aguiar, Flávio Henrique Baggio; Marchi, Giselle Maria

    2012-08-01

    The aim of the present study was to evaluate the degree of conversion (DC), elastic modulus (E), and flexural strength (FS) of five adhesive systems (only the bonding component of both Scotchbond MP-SBMP and Clearfil Protect Bond-CP; Single Bond 2-SB2; One-up Bond F Plus-OUP; and P90 System Adhesive: primer-P90P and bond-P90B) cured with a quartz tungsten halogen (QTH) lamp and a light-emitting diode (LED). Two groups per adhesive were formed (n=5), according to the light source (quartz tungsten halogen-QTH: Demetron LC; and light-emitting diode-LED: UltraLume 5). Bar-shaped specimens were evaluated using three-point bending. The DC was obtained by Fourier transform infrared spectroscopy (FTIR). SB2 and P90P exhibited better DC values for QTH curing. However, SB2 and P90P presented the worst results overall. The light source was statistically significant for all adhesives, except for P90B and OUP. Non-solvated adhesives presented the best E and FS values. It could be concluded that the DC and E values can be influenced by the light source; however, this interference is material dependent. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Effects of irradiance and light spectrum on growth of the scleractinian coral Galaxea

    NARCIS (Netherlands)

    Wijgerde, T.H.M.; Henkemans, P.; Osinga, R.

    2012-01-01

    Due to global degradation of coral reefs and high demand for scleractinian corals, aquaculture of these marine organisms is gaining importance. To make coral aquaculture economically viable, optimisation of culture protocols is vital. We determined the effects of irradiance and light spectrum on the

  20. Photoluminescence and reflectivity studies of high energy light ions irradiated polymethyl methacrylate films

    Science.gov (United States)

    Bharti, Madhu Lata; Singh, Fouran; Ramola, R. C.; Joshi, Veena

    2017-11-01

    The self-standing films of non-conducting polymethyl methacrylate (PMMA) were irradiated in vacuum using high energy light ions (HELIs) of 50 MeV Lithium (Li+3) and 80 MeV Carbon (C+5) at various ion dose to induce the optical changes in the films. Upon HELI irradiation, films exhibit a significant enhancement in optical reflectivity at the highest dose. Interestingly, the photoluminescence (PL) emission band with green light at (514.5 nm) shows a noticeable increase in the intensity with increasing ion dose for both ions. However, the rate of increase in PL intensity is different for both HELI and can be correlated with the linear energy transfer by these ions in the films. Origin of PL is attributed to the formation of carbon cluster and hydrogenated amorphous carbon in the polymer films. HAC clusters act as PL active centres with optical reflectivity. Most of the harmful radiation like UV are absorbed by the material and is becoming opaque after irradiation and this PL active material are useful in fabrication of optoelectronic devices, UV-filter, back-lit components in liquid crystal display systems, micro-components for integrate optical circuits, diffractive elements, advanced materials and are also applicable to the post irradiation laser treatment by means of ion irradiation.

  1. Clinical efficacy of blue light full body irradiation as treatment option for severe atopic dermatitis.

    Science.gov (United States)

    Becker, Detlef; Langer, Elise; Seemann, Martin; Seemann, Gunda; Fell, Isabel; Saloga, Joachim; Grabbe, Stephan; von Stebut, Esther

    2011-01-01

    Therapy of atopic dermatitis (AD) relies on immunosuppression and/or UV irradiation. Here, we assessed clinical efficacy and histopathological alterations induced by blue light-treatment of AD within an observational, non-interventional study. 36 patients with severe, chronic AD resisting long term disease control with local corticosteroids were included. Treatment consisted of one cycle of 5 consecutive blue light-irradiations (28.9 J/cm(2)). Patients were instructed to ask for treatment upon disease exacerbation despite interval therapy with topical corticosteroids. The majority of patients noted first improvements after 2-3 cycles. The EASI score was improved by 41% and 54% after 3 and 6 months, respectively (p≤0.005, and p≤0.002). Significant improvement of pruritus, sleep and life quality was noted especially after 6 months. Also, frequency and intensity of disease exacerbations and the usage of topical corticosteroids was reduced. Finally, immunohistochemistry of skin biopsies obtained at baseline and after 5 and 15 days revealed that, unlike UV light, blue light-treatment did not induce Langerhans cell or T cell depletion from skin. Blue light-irradiation may represent a suitable treatment option for AD providing long term control of disease. Future studies with larger patient cohorts within a randomized, placebo-controlled clinical trial are required to confirm this observation.

  2. Clinical efficacy of blue light full body irradiation as treatment option for severe atopic dermatitis.

    Directory of Open Access Journals (Sweden)

    Detlef Becker

    Full Text Available BACKGROUND: Therapy of atopic dermatitis (AD relies on immunosuppression and/or UV irradiation. Here, we assessed clinical efficacy and histopathological alterations induced by blue light-treatment of AD within an observational, non-interventional study. METHODOLOGY/PRINCIPAL FINDINGS: 36 patients with severe, chronic AD resisting long term disease control with local corticosteroids were included. Treatment consisted of one cycle of 5 consecutive blue light-irradiations (28.9 J/cm(2. Patients were instructed to ask for treatment upon disease exacerbation despite interval therapy with topical corticosteroids. The majority of patients noted first improvements after 2-3 cycles. The EASI score was improved by 41% and 54% after 3 and 6 months, respectively (p≤0.005, and p≤0.002. Significant improvement of pruritus, sleep and life quality was noted especially after 6 months. Also, frequency and intensity of disease exacerbations and the usage of topical corticosteroids was reduced. Finally, immunohistochemistry of skin biopsies obtained at baseline and after 5 and 15 days revealed that, unlike UV light, blue light-treatment did not induce Langerhans cell or T cell depletion from skin. CONCLUSIONS/SIGNIFICANCE: Blue light-irradiation may represent a suitable treatment option for AD providing long term control of disease. Future studies with larger patient cohorts within a randomized, placebo-controlled clinical trial are required to confirm this observation.

  3. Selective irradiation of radicals for biomedical treatment using vacuum ultraviolet light from an excimer lamp

    Science.gov (United States)

    Ono, Ryo; Tokumitsu, Yusuke; Zen, Shungo; Yonemori, Seiya

    2014-10-01

    In plasma medicine, radicals are considered to play important roles. However, the medical effect of each radical, such as OH and O, is unknown. To examine the effect of each radical, selective production of radicals is needed. We developed selective production of radicals for biomedical treatment using a vacuum ultraviolet (VUV) light emitted from an excimer lamp. Selective irradiation of OH radicals can be achieved by irradiating the 172-nm VUV light from a Xe2 excimer lamp to a humid helium flow in a quartz tube. The water molecules are strongly photodissociated by the VUV light to produce OH radicals. A photochemical simulation for the selective OH production is developed to calculate the OH density. The calculated OH density is compared with OH density measured using laser-induced fluorescence (LIF). Selective production of other radicals than OH is also discussed.

  4. Irradiance Decay in Fluorescent and Light-emitting Diode-based Phototherapy Devices: A Pilot Study.

    Science.gov (United States)

    Olusanya, Bolajoko O; Osibanjo, Folashade B; Emokpae, Abieyuwa A; Slusher, Tina M

    2016-10-01

    We set out to determine the rate of decline of irradiance for fluorescent tube (FT) and light-emitting diode (LED) phototherapy devices in resource-limited settings where routine irradiance monitoring is uncommon. Irradiance levels (μW/cm(2)/nm) were measured weekly using BiliBlanket(®) II Meter on three FT-based and two LED-based phototherapy devices over a 19 week period. The two LED devices showed stable irradiance levels and did not require any lamp changes. The three FT-based devices showed rapid decline in irradiance, and all required three complete lamp exchanges approximately every 5-6 weeks. FT-based devices are associated with more rapid decline in irradiance to sub-therapeutic levels and require more frequent lamp changes than LED devices. Clinicians should be alert to the maintenance requirements of the phototherapy devices available in their settings to ensure efficacy of treatment. © The Author [2016]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Further studies on the survival of non-proliferating human diploid fibroblasts irradiated with ultraviolet light

    Energy Technology Data Exchange (ETDEWEB)

    Chan, G.L.; Little, J.B. (Harvard Univ., Boston, MA (USA). School of Public Health)

    1982-04-01

    Labelling index data showed that in AG1518 cells, a diploid human fibroblast strain, there was a lag period of at least 14 hours between subculture from the density-inhibited plateau phase of growth and entry into DNA synthesis. Cells irradiated with 254nm wavelength U.V. light 8 hours after subculture did not exhibit the same degree of resistance as cells irradiated in plateau phase and subcultured immediately. When cells were arrested from proliferation by maintenance in an arginine and glutamine deficient medium for 72 hours, they were nearly as resistant to U.V. light as plateau phase cells although maintenance in this medium for 24 hours after irradiation supported further recovery only after low U.V. doses. One strain of Cockayne syndrome fibroblasts was found to be resistant to U.V. light in plateau phase while another strain was found to have the same survival response whether it was irradiated in the plateau or log phase of growth.

  6. Degradation of 4-methylbenzylidene camphor (4-MBC Using Fenton, UV Light Irradiation and Photo-Fenton

    Directory of Open Access Journals (Sweden)

    Ji Chunmei

    2017-01-01

    Full Text Available As one of the most commonly employed UV-filters, 4-methylbenzylidene camphor (4-MBC has been shown to accumulate in the environment and have endocrine disrupting activity. 4-MBC cannot be degraded completely by common methods in wastewater treatment plants. To prevent the environmental problems caused by 4-MBC from being more serious, finding effective method to degrade 4-MBC is essential. In this research, Fenton reaction and photo-Fenton was employed to degrade the 4-MBC. Orthogonal experimental design was employed to evaluate the influence of factors (Fe2+, H2O2, pH and reaction time on the degradation of 4-MBC. The degradation rate reached to 66.01% in Fenton process and 96.71% in photo-Fenton process. UV light irradiation was also employed to degrade 4-MBC. After being irradiated by mercury lamp (300W 90 min, the concentration of the 4-MBC reduced 85.4%, but most of them translated to the isomeride. Compared with the Fenton, photo-Fenton and UV light irradiation processes, we deduces that photo-Fenton can get the better degradation efficiency of 4-MBC, and, Fenton reagents and light irradiation are synergistic.

  7. In vitro comparative study of share bond of light cured composite resins with halogen light and argon laser, using stainless steel brackets on human premolars; Estudo comparativo in vitro da capacidade adesiva da resina fotoativada pela luz halogena e por laser de argonio, utilizando-se brackets metalicos em pre-molares humanos

    Energy Technology Data Exchange (ETDEWEB)

    Carillo, Vitoria Eugenia Bismarck

    2004-07-01

    The aim of this study in vitro was to compare the share bond strength of the light-cured composite resins Transbond XT (Unitek), with halogen light and argon laser. The Adhesive Remmant Index (ARI) was also investigated. The brackets Dyna lock (3M-UNITEK) were bonded to 75 human premolars, divided into 5 groups (15 each) according to time and the polymerization: Group H20, 15 brackets bonded with halogen light for 20s (10s both sides); Group H40, 15 brackets bonded with halogen light for 40s (20s both sides); Group A40, 15 brackets bonded with argon laser for 40s (20s both sides); Group A20, 15 brackets bonded with argon laser for 20s (10s both sides); Group A10, 15 brackets bonded with argon laser for 10s (5s both sides). The pulpal temperature changes were determined during a polymerization, not exceeding 3,5 deg C. After bonding, the teeth were submitted to a thermo cycled of 700 cycles between 5 deg C and 55 deg C, to simulate the consuming that the light cured composite resin would have in a short space of time. The specimens were then placed in PVC ring and embedded in acrylic resin (Aero-Jet). The tensile bond strength test was performed on an Universal Machine set at a crosshead speed of 1,5 mm/min, and for each rupture we registered a graphic and the best load required in Newtons, was converted to MPa and kgf. The share bond strength showed bigger values for the exposure time of 20 seconds, for the Group bonded for halogen light (H20), 7,45 kgf (7,64 MPa) and for argon laser 7,50 kgf (7,69 MPa); lesser values for the exposure time of 40s for the Group with halogen light (H40), 6,15 kgf (6,30 MPa) and argon laser Group (A40), 6,20 kgf (6,35 MPa) 0; and A10, 4,85 kgf (4,97 MPa). In the ARI Index, only A40 Group showed the 1 Index, with statistical results. In this Group, less than half of the remainder adhesive stayed on the surface of the enamel, conferring specimens failed at the enamel-adhesive interface. The results of the in vitro study demonstrate that

  8. Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection

    Science.gov (United States)

    Barber, Larry B.; Hladik, Michelle; Vajda, Alan M.; Fitzgerald, Kevin C.; Douville, Chris

    2015-01-01

    The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m3 d−1 design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration = 2.7 μg L−1; n=5) and 10 HDBPs (mean total concentration = 4.5 μg L−1), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration = 1.4 μg L−1) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative

  9. Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection.

    Science.gov (United States)

    Barber, Larry B; Hladik, Michelle L; Vajda, Alan M; Fitzgerald, Kevin C; Douville, Chris

    2015-10-01

    The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m(3) d(-1) design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration=2.7 μg L(-1); n=5) and 10 HDBPs (mean total concentration=4.5 μg L(-1)), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration=1.4 μg L(-1)) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative proportions of

  10. The Influence of Visible Light on the Sulfhydryl Content of Yeast Cells After Ionizing and Ultraviolet Irradiation

    Science.gov (United States)

    1951-12-15

    u„ Report No. 72 AMRt Project No. 6 -59-08-013 -S-4 MEDEA 15 December 1951 ABSTRACT // THE INFLUENCE OF VISIBLE LIGHT ON THE SULFHYDRYL...effect of visible light on ultraviolet irradiated cells) has shed new light on the complexities of the irradiation phenomena, but the under- lying...136, 1943. Vi 4. Lea, D. E. Actions of radiations onliving cells * New York, ’ Macmillan, 1947. 5. Keiner, A. Photore activation of

  11. Chlorine-functionalized carbon dots for highly efficient photodegradation of pollutants under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Shengliang, E-mail: hsliang@yeah.net [School of Material Science and Engineering, North University of China, Taiyuan 030051 (China); Ding, Yanli [School of Material Science and Engineering, North University of China, Taiyuan 030051 (China); Chang, Qing, E-mail: changneu@gmail.com [School of Material Science and Engineering, North University of China, Taiyuan 030051 (China); Yang, Jinlong [State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China); Lin, Kui, E-mail: linkui@tju.edu.cn [Analytical Instrumentation Center, Tianjin University, Tianjin 300072 (China)

    2015-11-15

    Graphical abstract: Chlorine-functionalized carbon dots (Cl-CDs) were synthesized through the substitution reaction. Cl-CDs show highly photocatalytic activity under visible-light irradiation, and can quickly degrade phthalocyanine with the thermal and chemical stability. This work suggests that surface engineering of carbon dots with heteroatoms can be used to enhance their photochemical properties. - Highlights: • Chlorine-functionalized carbon dots (Cl-CDs) were synthesized by substitution reaction. • Cl-CDs show highly photocatalytic activity under visible-light irradiation. • The thermally and chemically stable phthalocyanine is even photodegraded by Cl-CDs. - Abstract: Chlorine-functionalized carbon dots (Cl-CDs) were prepared by the substitution reaction between Cl radicals into thionyl chloride molecules and carbon dots with containing OH/COOH groups at their surface (O-CDs). The obtained Cl-CDs with a size of 2–5 nm contain 2–3% Cl atoms and emit blue light. Compared with amine-functionalzed carbon dots (N-CDs) and O-CDs, Cl-CDs exhibit much higher photocatalytic activity under visible-light irradiation. The thermally and chemically stable phthalocyanine can be even degraded quickly through Cl-CDs. This work suggests that surface engineering of carbon dots with heteroatoms can be used to enhance their photochemical properties.

  12. Comparison of the alendronate and irradiation with a light-emitting diode (LED) on murine osteoclastogenesis.

    Science.gov (United States)

    Sohn, Hong Moon; Ko, Youngjong; Park, Mineon; Kim, Bora; Park, Jung Eun; Kim, Donghwi; Moon, Young Lae; Lim, Wonbong

    2017-01-01

    Photomodulation therapy (PBMT) using light-emitting diode (LED) has been proposed as an alternative to conventional osteoporosis therapies. Our aim was to determine the effect of irradiation with a light-emitting diode on receptor activator of NF-κB ligand (RANKL)-mediated differentiation of mouse bone marrow macrophages into osteoclasts and compare it to alendronate treatment. The cells were irradiated with LED at 635±10 nm, 9-cm spot size, 5 mW/cm2, and 18 J for 60 min/day in a CO2 incubator. The differentiation of irradiated and untreated RANKL-stimulated bone marrow macrophages into osteoclasts was evaluated by tartrate-resistant acid phosphatase (TRAP) staining and by molecular methods. These included assessing messenger RNA (mRNA) expression of osteoclastic markers such as TRAP, c-Fos, Atp6v0d2, DC-STAMP, NFATc1, cathepsin K, MMP9 and OSCAR; phosphorylation of various MAPKs, including extracellular signal-regulated kinase ERK1/2, P38, and JNK; NF-κB translocation; and resorption pit formation. Results were compared to those obtained with sodium alendronate. Production of reactive oxygen species was measured by a 2',7'-dihydrodichlorofluorescein diacetate assay. LED irradiation and alendronate inhibited mRNA expression of osteoclast-related genes, such as TRAP, c-Fos, and NFATc1, and reduced the osteoclast activity of RANKL-stimulated bone marrow macrophages. LED irradiation, but not alendronate, also inhibited the production of reactive oxygen species (ROS); phosphorylation of ERK, P38, and IκB; and NF-κB translocation. These findings suggest that LED irradiation downregulates osteoclastogenesis by ROS production; this effect could lead to reduced bone loss and may offer a new therapeutic tool for managing osteoporosis.

  13. Regulation of ascorbic acid metabolism by blue LED light irradiation in citrus juice sacs.

    Science.gov (United States)

    Zhang, Lancui; Ma, Gang; Yamawaki, Kazuki; Ikoma, Yoshinori; Matsumoto, Hikaru; Yoshioka, Terutaka; Ohta, Satoshi; Kato, Masaya

    2015-04-01

    In the present study, the effects of red and blue LED lights on the accumulation of ascorbic acid (AsA) were investigated in the juice sacs of three citrus varieties, Satsuma mandarin, Valencia orange, and Lisbon lemon. The results showed that the blue LED light treatment effectively increased the AsA content in the juice sacs of the three citrus varieties, whereas the red LED light treatment did not. By increasing the blue LED light intensity, the juice sacs of the three citrus varieties accumulated more AsA. Moreover, continuous irradiation with blue LED light was more effective than pulsed irradiation for increasing the AsA content in the juice sacs of the three citrus varieties. Gene expression results showed that the modulation of AsA accumulation by blue LED light was highly regulated at the transcription level. The up-regulation of AsA biosynthetic genes (CitVTC1, CitVTC2, CitVTC4, and CitGLDH), AsA regeneration genes (CitMDAR1, CitMDAR2, and CitDHAR) and two GSH-producing genes (CitGR and CitchGR) contributed to these increases in the AsA content in the three citrus varieties. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. Effect of LED-LCU light irradiance distribution on mechanical properties of resin based materials.

    Science.gov (United States)

    Magalhães Filho, T R; Weig, K M; Costa, M F; Werneck, M M; Barthem, R B; Costa Neto, C A

    2016-06-01

    The objective of this study is to analyze the light power distribution along the tip end of the light guide of three LED-LCUs (Light Curing Units) and to evaluate its effect on the mechanical properties of a polymer based dental composite. Firstly, the light power distribution over the whole area of LED-LCU light guide surface was analyzed by three methods: visual projection observation, spectral measurement and optical spectral analysis (OSA). The light power distribution and the total irradiance were different for the three LEDs used, but the wavelength was within the camphorquinone absorption spectrum. The use of a blank sheet was quite on hand to make a qualitative analysis of a beam, and it is costless. Secondly, specimens of a hybrid composite with approximately 8mm diameter and 2mm thickness were produced and polymerized by 20s exposition time to each LED-LCU. Thirdly, the elastic modulus (E) and hardness (HV) were measured throughout the irradiated area by instrumented micro-indentation test (IIT), allowing to correlate localized power and mechanical properties. Both E and HV showed to be very sensitive to local power and wavelength dependent, but they followed the beam power profile. It was also shown that the mechanical properties could be directly correlated to the curing process. Very steep differences in mechanical properties over very short distances may impair the material performance, since residual stresses can easily be built over it. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Sundin, Peter; Wesén, Clas

    1997-01-01

    and separation method. This review covers separation by solid phase chromatography, gel permeation chromatography, and liquid-liquid extraction, followed by halogen determination. All studies performed according to this outline have indicated that the major organohalogen compounds are chlorinated fatty acids...... bound in different lipids. For the detection and identification of individual, halogenated fatty acid methyl esters (FAMEs) liberated from the lipids, gas chromatography (GC) has been employed together with detection methods such as electron capture detection, electrolytic conductivity detection (ELCD......), atomic emission spectrometry, and mass spectrometry. For most environmental samples, chlorinated FAMEs must be enriched prior to GC. ELCD is a useful detection method for indicating halogenated FAMEs in the chromatograms, and tentative identification of the halogenated species can be obtained...

  16. Low-irradiance red LED traffic lamps as light source in PDT for actinic keratoses.

    Science.gov (United States)

    Enk, Claes D; Levi, Assi

    2012-12-01

    LED light sources for photodynamic therapy have become increasingly popular due to their narrow emission spectra that accurately match the absorption spectrum of porphyrins. Photodynamic therapy at low fluence rates has been shown to be as effective as high output irradiation for treatment of non-melanoma skin cancers. Fifteen patients with multiple non-hypertrophic actinic keratoses covering the scalp and the face were treated with aminolaevulinic acid photodynamic therapy using ordinary red LED traffic lamps as light source. All 15 patients improved clinically after one photodynamic therapy session. Only two patients required a second session to obtain satisfactory remission. Pain was minimal during these sessions. Red LED traffic lights constitute a simple alternative to far more complicated and expensive PDT light sources. © 2012 John Wiley & Sons A/S.

  17. Light based anti-infectives: ultraviolet C irradiation, photodynamic therapy, blue light, and beyond.

    Science.gov (United States)

    Yin, Rui; Dai, Tianhong; Avci, Pinar; Jorge, Ana Elisa Serafim; de Melo, Wanessa C M A; Vecchio, Daniela; Huang, Ying-Ying; Gupta, Asheesh; Hamblin, Michael R

    2013-10-01

    Owing to the worldwide increase in antibiotic resistance, researchers are investigating alternative anti-infective strategies to which it is supposed microorganisms will be unable to develop resistance. Prominent among these strategies, is a group of approaches which rely on light to deliver the killing blow. As is well known, ultraviolet light, particularly UVC (200-280 nm), is germicidal, but it has not been much developed as an anti-infective approach until recently, when it was realized that the possible adverse effects to host tissue were relatively minor compared to its high activity in killing pathogens. Photodynamic therapy is the combination of non-toxic photosensitizing dyes with harmless visible light that together produce abundant destructive reactive oxygen species (ROS). Certain cationic dyes or photosensitizers have good specificity for binding to microbial cells while sparing host mammalian cells and can be used for treating many localized infections, both superficial and even deep-seated by using fiber optic delivered light. Many microbial cells are highly sensitive to killing by blue light (400-470 nm) due to accumulation of naturally occurring photosensitizers such as porphyrins and flavins. Near infrared light has also been shown to have antimicrobial effects against certain species. Clinical applications of these technologies include skin, dental, wound, stomach, nasal, toenail and other infections which are amenable to effective light delivery. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Effect of LED-LCU light irradiance distribution on mechanical properties of resin based materials

    Energy Technology Data Exchange (ETDEWEB)

    Magalhães Filho, T.R.; Weig, K.M. [Faculdade de Odontologia, Universidade Federal Fluminense, Rua São Paulo 28, CEP 24020-150 Niterói (Brazil); Engenharia Metalúrgica e de Materiais (COPPE), Universidade Federal do Rio de Janeiro, CP 68505, CEP: 21941-972 Rio de Janeiro (Brazil); Costa, M.F. [Engenharia Metalúrgica e de Materiais (COPPE), Universidade Federal do Rio de Janeiro, CP 68505, CEP: 21941-972 Rio de Janeiro (Brazil); Werneck, M.M. [Engenharia Elétrica (COPPE), Universidade Federal do Rio de Janeiro, CP 68504, CEP: 21941-972 Rio de Janeiro (Brazil); Barthem, R.B. [Instituto de Física, Universidade Federal do Rio de Janeiro, CP 68528, CEP: 21941-972 Rio de Janeiro (Brazil); Costa Neto, C.A., E-mail: celio@metalmat.ufrj.br [Engenharia Metalúrgica e de Materiais (COPPE), Universidade Federal do Rio de Janeiro, CP 68505, CEP: 21941-972 Rio de Janeiro (Brazil)

    2016-06-01

    The objective of this study is to analyze the light power distribution along the tip end of the light guide of three LED-LCUs (Light Curing Units) and to evaluate its effect on the mechanical properties of a polymer based dental composite. Firstly, the light power distribution over the whole area of LED-LCU light guide surface was analyzed by three methods: visual projection observation, spectral measurement and optical spectral analysis (OSA). The light power distribution and the total irradiance were different for the three LEDs used, but the wavelength was within the camphorquinone absorption spectrum. The use of a blank sheet was quite on hand to make a qualitative analysis of a beam, and it is costless. Secondly, specimens of a hybrid composite with approximately 8 mm diameter and 2 mm thickness were produced and polymerized by 20 s exposition time to each LED-LCU. Thirdly, the elastic modulus (E) and hardness (HV) were measured throughout the irradiated area by instrumented micro-indentation test (IIT), allowing to correlate localized power and mechanical properties. Both E and HV showed to be very sensitive to local power and wavelength dependent, but they followed the beam power profile. It was also shown that the mechanical properties could be directly correlated to the curing process. Very steep differences in mechanical properties over very short distances may impair the material performance, since residual stresses can easily be built over it. - Highlights: • A resin based composite (RBC) was polymerized by three different Light Emitting Diodes. • Each LED had its beam profile visually, wavelength and power analyzed. • The effective polymerization power (EPP) varied from 28% to 52% of the total beam power. • Wavelength seems to be as relevant as power in the light curing process. • Mechanical properties depend on the simultaneous effect of wavelength and power.

  19. Catalyst-free activation of peroxides under visible LED light irradiation through photoexcitation pathway

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yaowen [Department of Environmental Engineering, Wuhan University, Wuhan, 430079 (China); Shenzhen Research Institute of Wuhan University, Shenzhen, 518057 (China); Li, Yixi; Yao, Linyu; Li, Simiao; Liu, Jin [Department of Environmental Engineering, Wuhan University, Wuhan, 430079 (China); Zhang, Hui, E-mail: eeng@whu.edu.cn [Department of Environmental Engineering, Wuhan University, Wuhan, 430079 (China); Shenzhen Research Institute of Wuhan University, Shenzhen, 518057 (China)

    2017-05-05

    Highlights: • Persulfate could decolorize Rhodamine B (RhB) directly via non-radical reactions. • LED lamps emitting white light were utilized as the visible light source. • Dyes could activate peroxides through photoexcitation pathway. • Decolorization of dyes and production of radicals were achieved simultaneously. • The catalyst-free peroxide/dye/Vis process was effective in a broad pH range. - Abstract: Catalysts are known to activate peroxides to generate active radicals (i.e., hydroxyl radical (·OH) and sulfate radical (SO{sub 4}·{sup −})) under certain conditions, but the activation of peroxides in the absence of catalysts under visible light irradiation has been rarely reported. This work demonstrates a catalyst-free activation of peroxides for the generation of ·OH and/or SO{sub 4}·{sup −} through photoexcited electron transfer from organic dyes to peroxides under visible LED light irradiation, where Rhodamine B (RhB) and Eosin Y (EY) were selected as model dyes. The formation of ·OH and/or SO{sub 4}·{sup −} in the reactions and the electron transfer from the excited dyes to peroxides were validated via electron paramagnetic resonance (EPR), photoluminescence (PL) spectra and cyclic voltammetry (CV). The performance of the peroxide/dye/Vis process was demonstrated to be altered depending on the target substrate. Meanwhile, the peroxide/dye/Vis process was effective for simultaneous decolorization of dyes and production of active radicals under neutral even or basic conditions. The findings of this study clarified a novel photoexcitation pathway for catalyst-free activation of peroxides under visible light irradiation, which could avoid the secondary metal ion (dissolved or leached) pollution from the metal-based catalysts and expand the application range of the peroxide-based catalytic process.

  20. Effect of low energy light irradiation by light emitting diode on U937 cells.

    Science.gov (United States)

    Spoto, G; De Iuliis, V; Petrini, M; Flati, V; Di Gregorio, J; Vitale, D; Caruso, M; Dadorante, V; Ciarmoli, M; Robuffo, I; Martinotti, S; Toniato, E

    2016-01-01

    Photobiomodulation (PBM) can induce a set of different biological modulators either in vitro or in vivo. Experimental evidence has highlighted the role of light effects on the mechanisms related to inflammation, apoptosis and autophagy. The goal of this project was the evaluation of PBM on U937, an established cell line of histiocytic lymphoma origin. Several aspects of modulation of proinflammatory pathways were analyzed and autophagic and proapoptotic mechanisms related to low laser light exposure of cells were studied. As a source of low energy light emission, we used an NIR-LED device, characterized by an 880 nm-wavelength as light source. Flow cytometry analysis was performed on supernatants of controls and treated U937 cells to detect inflammatory cytokine levels. In order to evaluate NF-kB and caspase3 expressions, Western blot analysis was performed according to standard procedures. In this report, we show the effect of PBM on a monocyte/macrophage established tumor cell line (U-937). We demonstrate that LED exposure, in the presence or absence of lipopolysaccharide (LPS), activates cell degranulation, increased expression of Interleukin-8 (IL-8) and modulation of beta galactosidase activity. Evidence shows that the well-known pro-inflammatory nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and the apoptotic marker (caspase3/cleaved-caspase3 ratio) are up-regulated in response to a proinflammatory biochemical pathway.

  1. Photocatalytic activity of polymer-modified ZnO under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Rongliang [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)], E-mail: eesqrl@mail.sysu.edu.cn; Zhang Dongdong [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Mo Yueqi [College of Material Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Song Lin [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Department of Environmental Engineering, Jinan University, Guangzhou 510630 (China); Brewer, Eric [Viridian Environmental, LLC, Arlington, VA 22207 (United States); Huang Xiongfei; Xiong Ya [School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

    2008-08-15

    Photocatalytic removal of phenol, rhodamine B, and methyl orange was studied using the photocatalyst ZnO/poly-(fluorene-co-thiophene) (PFT) under visible light. After 2 h irradiation with three 1 W LED (light-emitting diode) lights, about 40% removal of both phenol and methyl orange was achieved; rhodamine B was completely degraded to rhodamine. Diffuse reflectance spectra showed that the absorbance range of PFT/ZnO was expanded from 387 nm (ZnO) to about 500 nm. Photoluminescent spectra and photoluminescent quantum efficiency indicated that electrons were transferred from PFT to the conduction band of ZnO. Electron spin resonance (ESR) signals of spin-trapped paramagnetic species with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) evidenced that the OH{center_dot} radicals were indeed formed in the PFT/ZnO system under visible light irradiation. A working mechanism involving excitation of PFT, followed by charge injection into the ZnO conduction band is proposed.

  2. Light energy attenuation through orthodontic ceramic brackets at different irradiation times.

    Science.gov (United States)

    Santini, Ario; Tiu, Szu Hui; McGuinness, Niall J P; Aldossary, Mohammed Saeed

    2016-09-01

    To evaluate the total light energy (TLE) transmission through three types of ceramic brackets with, bracket alone and with the addition of orthodontic adhesive, at different exposure durations, and to compare the microhardness of the cured adhesive. Three different makes of ceramic brackets, Pure Sapphire(M), Clarity™ ADVANCED(P) and Dual Ceramic(P) were used. Eighteen specimens of each make were prepared and allocated to three groups (n = 6). MARC(®)-resin calibrator was used to determine the light curing unit (LCU) tip irradiance (mW/cm(2)) and TLE (J/cm(2)) transmitted through the ceramic brackets, and through ceramic bracket plus Transbond™ XT Light Cure Adhesive, for 5, 10 and 20 s. Vickers-hardness values at the bottom of the cured adhesive were determined. Statistical analysis used one-way analysis of variance (ANOVA); P = 0.05. TLE transmission rose significantly among all samples with increasing exposure durations. TLE reaching the adhesive- enamel interface was less than 10 J/cm(2), and through monocrystalline and polycrystalline ceramic brackets was significantly different (P brackets. Clinicians are advised to measure the tip irradiance of their LCUs and increase curing time beyond 5 s. Orthodontic clinicians should understand the type of light curing device and the orthodontic adhesive used in their practice.

  3. Spectral responses of the human circadian system depend on the irradiance and duration of exposure to light.

    Science.gov (United States)

    Gooley, Joshua J; Rajaratnam, Shantha M W; Brainard, George C; Kronauer, Richard E; Czeisler, Charles A; Lockley, Steven W

    2010-05-12

    In humans, modulation of circadian rhythms by light is thought to be mediated primarily by melanopsin-containing retinal ganglion cells, not rods or cones. Melanopsin cells are intrinsically blue light-sensitive but also receive input from visual photoreceptors. We therefore tested in humans whether cone photoreceptors contribute to the regulation of circadian and neuroendocrine light responses. Dose-response curves for melatonin suppression and circadian phase resetting were constructed in subjects exposed to blue (460 nm) or green (555 nm) light near the onset of nocturnal melatonin secretion. At the beginning of the intervention, 555-nm light was equally effective as 460-nm light at suppressing melatonin, suggesting a significant contribution from the three-cone visual system (lambda(max) = 555 nm). During the light exposure, however, the spectral sensitivity to 555-nm light decayed exponentially relative to 460-nm light. For phase-resetting responses, the effects of exposure to low-irradiance 555-nm light were too large relative to 460-nm light to be explained solely by the activation of melanopsin. Our findings suggest that cone photoreceptors contribute substantially to nonvisual responses at the beginning of a light exposure and at low irradiances, whereas melanopsin appears to be the primary circadian photopigment in response to long-duration light exposure and at high irradiances. These results suggest that light therapy for sleep disorders and other indications might be optimized by stimulating both photoreceptor systems.

  4. A study on the irradiation embrittlement and recovery characteristics of light water reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Se Hwan; Hong, Jun Hwa; Lee, Bong Sang; Oh, Jong Myung; Song, Sook Hyang; Milan, Brumovsky [NRI Czech (Czech Republic)

    1999-03-01

    The neutron irradiation embrittlement phenomenon of light water RPV steels greatly affects the life span for safe operation of a reactor. Reliable evaluation and prediction of the embrittlement of RPV steels, especially of aged reactors, are of importance to the safe operation of a reactor. In addition, the thermal recovery of embrittled RPV has been recognized as an option for life extension. This study aimed to tracer/refine available technologies for embrittlement characterization and prediction, to prepare relevant materials for several domestic RPV steels of the embrittlement and recovery, and to find out possible remedy for steel property betterment. Small specimen test techniques, magnetic measurement techniques, and the Meechan and Brinkmann's recovery curve analysis method were examined/applied as the evaluation techniques. Results revealed a high irradiation sensitivity in YG 3 RPV steel. Further extended study may be urgently needed. Both the small specimen test technique for the direct determination of fracture toughness, and the magnetic measurement technique for embrittlement evaluation appeared to be continued for the technical improvement and data base preparation. Manufacturing process relevant to the heat treatment appeared to be improved in lowering the irradiation sensitivity of the steel. Further study is needed especially in applying the present techniques to the new structural materials under new irradiation environment of advanced reactors. (author)

  5. Light irradiance through novel CAD-CAM block materials and degree of conversion of composite cements.

    Science.gov (United States)

    Lise, Diogo Pedrollo; Van Ende, Annelies; De Munck, Jan; Yoshihara, Kumiko; Nagaoka, Noriyuki; Cardoso Vieira, Luiz Clovis; Van Meerbeek, Bart

    2018-02-01

    To assess light irradiance (LI) delivered by two light-curing units (LCU's) and to measure the degree of conversion (DC) of three composite cements, when cured through different thicknesses of two novel CAD-CAM block materials. 100-μm-thick films of a dual-curable composite cement (G-CEM LinkAce, GC), a light-curable flowable resin-based composite (RBC) (G-ænial Universal Flo, GC) and a micro-hybrid RBC (G-ænial Posterior, GC) were investigated as luting agents. Two 'polymer-ceramic' CAD-CAM blocks (Cerasmart, GC; Enamic, Vita Zahnfabrik) were sectioned in slabs with different thicknesses (1, 3 and 5mm). LI at the bottom of the specimens was measured using a calibrated spectrometer, while being light-cured through the CAD-CAM block slabs for 40s with a low- (±500mW/cm 2 ) or high- (±1,600mW/cm 2 ) irradiance LCU (n=5). After light-curing, micro-Raman spectra of the composite films were acquired to determine DC at 5min, 10min, 1h and 24h. LI data were statistically analyzed by Kruskal-Wallis followed by post-hoc comparisons, while a linear mixed-effect model was applied for the DC analysis. In addition, the CAD-CAM blocks ultrastructure was characterized upon argon-ion slicing using scanning transmission electron microscopy (STEM). Finally, light transmission (LT) through each CAD-CAM block material was assessed using a spectrophotometer. Curing-light attenuation and DC were significantly influenced by thickness and type of the overlying material. LCU only had a significant effect on DC of the micro-hybrid RBC. DC significantly increased over time for all composite cements. CAD-CAM block structural analysis revealed a relatively small and homogenous filler configuration (mean filler size of 0.2-0.5μm) for Cerasmart, while Enamic contained ceramic grains varying in shape and size (1-10μm), which were interconnected by the polymer-based network. LT was much higher at a wavelength range of 300-800nm for Cerasmart than for Enamic. Light-curable composite cements

  6. Halogens in chondritic meteorites and terrestrial accretion

    Science.gov (United States)

    Clay, Patricia L.; Burgess, Ray; Busemann, Henner; Ruzié-Hamilton, Lorraine; Joachim, Bastian; Day, James M. D.; Ballentine, Christopher J.

    2017-11-01

    Volatile element delivery and retention played a fundamental part in Earth’s formation and subsequent chemical differentiation. The heavy halogens—chlorine (Cl), bromine (Br) and iodine (I)—are key tracers of accretionary processes owing to their high volatility and incompatibility, but have low abundances in most geological and planetary materials. However, noble gas proxy isotopes produced during neutron irradiation provide a high-sensitivity tool for the determination of heavy halogen abundances. Using such isotopes, here we show that Cl, Br and I abundances in carbonaceous, enstatite, Rumuruti and primitive ordinary chondrites are about 6 times, 9 times and 15-37 times lower, respectively, than previously reported and usually accepted estimates. This is independent of the oxidation state or petrological type of the chondrites. The ratios Br/Cl and I/Cl in all studied chondrites show a limited range, indistinguishable from bulk silicate Earth estimates. Our results demonstrate that the halogen depletion of bulk silicate Earth relative to primitive meteorites is consistent with the depletion of lithophile elements of similar volatility. These results for carbonaceous chondrites reveal that late accretion, constrained to a maximum of 0.5 ± 0.2 per cent of Earth’s silicate mass, cannot solely account for present-day terrestrial halogen inventories. It is estimated that 80-90 per cent of heavy halogens are concentrated in Earth’s surface reservoirs and have not undergone the extreme early loss observed in atmosphere-forming elements. Therefore, in addition to late-stage terrestrial accretion of halogens and mantle degassing, which has removed less than half of Earth’s dissolved mantle gases, the efficient extraction of halogen-rich fluids from the solid Earth during the earliest stages of terrestrial differentiation is also required to explain the presence of these heavy halogens at the surface. The hydropilic nature of halogens, whereby they track

  7. Influence of Light Irradiation Through Zirconia on the Degree of Conversion of Composite Cements.

    Science.gov (United States)

    Inokoshi, Masanao; Pongprueksa, Pong; De Munck, Jan; Zhang, Fei; Vanmeensel, Kim; Minakuchi, Shunsuke; Vleugels, Jozef; Naert, Ignace; Van Meerbeek, Bart

    2016-01-01

    To assess the light irradiance (LI) delivered by two light-curing units and to measure the degree of conversion (DC) of three composite cements and one flowable composite when cured through zirconia or ceramic-veneered zirconia plates with different thicknesses. Three dual-curing composite cements (Clearfil Esthetic Cement, Panavia F2.0, G-CEM LinkAce) and one light-curing flowable composite (G-aenial Universal Flo) were investigated. Nine different kinds of zirconia plates were prepared from three zirconia grades (YSZ: Aadva and KATANA; Ce-TZP/Al2O3: NANOZR) in three different thicknesses (0.5- and 1.5-mm-thick zirconia, and 0.5-mm-thick zirconia veneered with a 1.0-mm-thick veneering ceramic). Portions of the mixed composite cements and the flowable composite were placed on a light spectrometer to measure LI while being light cured through the zirconia plates for 40 s using two light-curing units (n = 5). After light curing, micro-Raman spectra of the composite films were acquired to determine DC at 5 and 10 min, 1 and 24 h, and at 1 week. The zirconia grade and the thickness of the zirconia/veneered zirconia plates significantly decreased LI. Increased LI did not increase DC. Only the Ce-TZP/Al2O3 (NANOZR) zirconia was too opaque to allow sufficient light transmission and resulted in significantly lower DC. Although zirconia-based restorations attenuate the LI of light-curing units, the composite cements and the flowable composite could be light cured through the YSZ zirconia. LI is too low through Ce-TZP/Al2O3 zirconia, necessitating the use of self-/dual-curing composite cements.

  8. Photolyase activity induction by UVC irradiation and visible light in barley root

    Energy Technology Data Exchange (ETDEWEB)

    Zukas, K.; Ambrozaitis, K. [University of Vilnius, Departement of Botany and Genetics, (Lithuania)

    1997-03-01

    Using Micrococcus luteus UV-endonuclease sensitive sites (EES) photoreactivation test, photolyase (PHL) activity has been detected in barley seedlings but not in extracts from barley roots. This lack of activity was used create a model system for the investigation of PHL activity induction. It was detected that short wave ultraviolet (UVC,{lambda}{sub max} = 254 nm, dose 1 kJ/m{sup 2}) induced PHL activity in roots after 60 min. post-irradiation incubation in a dark. Extract from roots of barley seedlings illuminated with a visible light (10 kJ/m{sup 2}) and maintained in a dark up to 90 min. cause PR of 46.7 % ESS in UV-irradiated DNA from Bacillus subtilis. (authors)

  9. Vitamin C affects the antioxidative/oxidative status in rats irradiated with ultraviolet (UV) and infrared (IR) light

    DEFF Research Database (Denmark)

    Niemiec, T.; Sawosz, E.; Chwalibog, André

    2006-01-01

    Four grups of twenty growing Wistar rats were irradiated with either UV, IR, UV+IR light or were not irradiated (control). Ten rats from each group received a diet supplemented with 0.6% of L-ascorbic acid. The effects of the mega-dose of vitamin C were evaluated by changes in the antioxidative....../oxidative status. UV and IR radiation promoted oxidative DNA degradation in rat livers and supplementation with ascorbic acid strengthened the prooxidative effects on DNA oxidation in rats irradiated with UV or IR light. Vitamin C also increased the tiobarbituric acid reactive substances (TBARS) concentration...

  10. Natural Genetic Variation for Acclimation of Photosynthetic Light Use Efficiency to Growth Irradiance in Arabidopsis1[OPEN

    Science.gov (United States)

    Harbinson, Jeremy

    2015-01-01

    Plants are known to be able to acclimate their photosynthesis to the level of irradiance. Here, we present the analysis of natural genetic variation for photosynthetic light use efficiency (ΦPSII) in response to five light environments among 12 genetically diverse Arabidopsis (Arabidopsis thaliana) accessions. We measured the acclimation of ΦPSII to constant growth irradiances of four different levels (100, 200, 400, and 600 µmol m−2 s−1) by imaging chlorophyll fluorescence after 24 d of growth and compared these results with acclimation of ΦPSII to a step-wise change in irradiance where the growth irradiance was increased from 100 to 600 µmol m−2 s−1 after 24 d of growth. Genotypic variation for ΦPSII is shown by calculating heritability for the short-term ΦPSII response to different irradiance levels as well as for the relation of ΦPSII measured at light saturation (a measure of photosynthetic capacity) to growth irradiance level and for the kinetics of the response to a step-wise increase in irradiance from 100 to 600 µmol m−2 s−1. A genome-wide association study for ΦPSII measured 1 h after a step-wise increase in irradiance identified several new candidate genes controlling this trait. In conclusion, the different photosynthetic responses to a changing light environment displayed by different Arabidopsis accessions are due to genetic differences, and we have identified candidate genes for the photosynthetic response to an irradiance change. The genetic variation for photosynthetic acclimation to irradiance found in this study will allow future identification and analysis of the causal genes for the regulation of ΦPSII in plants. PMID:25670817

  11. Changing Mechanical Strength in Cr(III)- Metallosupramolecular Polymers with Ligand Groups and Light Irradiation.

    Science.gov (United States)

    Razgoniaev, Anton O; Butaeva, Evgeniia V; Iretskii, Alexei V; Ostrowski, Alexis D

    2016-06-06

    We have demonstrated the ability to control the mechanical properties of metallosupramolecular materials via choice of ligand binding group, as well as with external light irradiation. These photoresponsive Cr(III)-based materials were prepared from a series of modified hydrogenated poly(ethylene-co-butylene) polymers linked through metal-ligand interactions between a Cr(III) metal center and pyridyl ligand termini of the polymers. The introduction of these Cr(III)-pyridine bonds gave rise to new mechanical and optical properties of the polymer materials. Depending on the type of pyridyl ligand, density functional theory calculations revealed changes in coordination to the Cr(III), which ultimately led to materials with significantly different mechanical properties. Electronic excitation of the Cr(III) materials with 450 and 655 nm CW lasers (800 mW/cm(2)) resulted in generation of excited state photophysical processes which led to temporary softening of the materials up to 143 kPa (41.5%) in storage modulus (G') magnitude. The initial mechanical strength of the materials was recovered when the light stimulus was removed, and no change in mechanical properties was observed with light irradiation where there was no absorbance by the Cr(III) moiety. These materials demonstrate that introduction of metal-ligand bonding interactions into polymers enables the design and synthesis of photoresponsive materials with tunable optical-mechanical properties not seen in traditional polymeric materials.

  12. Halogenated solvent remediation

    Science.gov (United States)

    Sorenson, Jr., Kent S.

    2008-11-11

    Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. An illustrative method includes adding an electron donor for microbe-mediated anaerobic reductive dehalogenation of the halogenated solvents, which electron donor enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative electron donors include C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof, of which lactic acid, salts of lactic acid--such as sodium lactate, lactate esters, and mixtures thereof are particularly illustrative. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the electron donor.

  13. Photocatalytic Degradation of Isopropanol Over PbSnO3Nanostructures Under Visible Light Irradiation

    Science.gov (United States)

    2009-01-01

    Nanostructured PbSnO3photocatalysts with particulate and tubular morphologies have been synthesized from a simple hydrothermal process. As-prepared samples were characterized by X-ray diffraction, Brunauer–Emmet–Teller surface area, transmission electron microscopy, and diffraction spectroscopy. The photoactivities of the PbSnO3nanostructures for isopropanol (IPA) degradation under visible light irradiation were investigated systematically, and the results revealed that these nanostructures show much higher photocatalytic properties than bulk PbSnO3material. The possible growth mechanism of tubular PbSnO3catalyst was also investigated briefly. PMID:20596379

  14. Culture of the green microalga Botryococcus braunii Showa with LED irradiation eliminating violet light enhances hydrocarbon production and recovery.

    Science.gov (United States)

    Atobe, Sueko; Saga, Kiyotaka; Maeyama, Haruko; Fujiwara, Kazuhiro; Okada, Shigeru; Imou, Kenji

    2014-01-01

    The green microalga Botryococcus braunii (B. braunii), race B, was cultured under light-emitting diode (LED) irradiation with and without violet light. This study examined the effect of violet light on hydrocarbon recovery and production in B. braunii. C34 botryococcene hydrocarbons were efficiently extracted by thermal pretreatments at lower temperatures when the alga was cultured without violet light. The hydrocarbon content was also higher (approximately 3%) in samples cultured without violet light. To elucidate the mechanism of effective hydrocarbon recovery and production, we examined structural components of the extracellular matrix (ECM). The amounts of extracellular carotenoids and water-soluble polymers extracted by thermal pretreatment from the ECM were decreased when the alga was cultured without violet light. These results indicate that LED irradiation without violet light is more effective for hydrocarbon recovery and production in B. braunii. Furthermore, structural ECM components are closely involved in hydrocarbon recovery and production in B. braunii.

  15. Halogenated fatty acids

    DEFF Research Database (Denmark)

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    , chlorinated lipids have been found in meat exposed to hypochlorite disinfected water, and in chlorine-treated flour and in products made from such flour. Following exposure to chlorine bleached pulp mill effluents, aquatic organisms may have elevated concentrations of chlorinated fatty acids in their lipids....... However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods...

  16. Oxidative photodecarboxylation of α-hydroxycarboxylic acid derivatives with FSM-16 under visible light irradiation of fluorescent lamp.

    Science.gov (United States)

    Tada, Norihiro; Matsusaki, Yoko; Miura, Tsuyoshi; Itoh, Akichika

    2011-01-01

    Hydroxycarboxylic acids were converted to the corresponding carbonyl compounds under aerobic photo-oxidative conditions in the presence of FSM-16 under visible light irradiation by a fluorescent lamp. This synthetic protocol is the first example of FSM-16 functioning as a photocatalyst by visible light.

  17. Water-filtered infrared a irradiation in combination with visible light inhibits acute chlamydial infection.

    Directory of Open Access Journals (Sweden)

    Hanna Marti

    Full Text Available New therapeutic strategies are needed to overcome drawbacks in treatment of infections with intracellular bacteria. Chlamydiaceae are Gram-negative bacteria implicated in acute and chronic diseases such as abortion in animals and trachoma in humans. Water-filtered infrared A (wIRA is short wavelength infrared radiation with a spectrum ranging from 780 to 1400 nm. In clinical settings, wIRA alone and in combination with visible light (VIS has proven its efficacy in acute and chronic wound healing processes. This is the first study to demonstrate that wIRA irradiation combined with VIS (wIRA/VIS diminishes recovery of infectious elementary bodies (EBs of both intra- and extracellular Chlamydia (C. in two different cell lines (Vero, HeLa regardless of the chlamydial strain (C. pecorum, C. trachomatis serovar E as shown by indirect immunofluorescence and titration by subpassage. Moreover, a single exposure to wIRA/VIS at 40 hours post infection (hpi led to a significant reduction of C. pecorum inclusion frequency in Vero cells and C. trachomatis in HeLa cells, respectively. A triple dose of irradiation (24, 36, 40 hpi during the course of C. trachomatis infection further reduced chlamydial inclusion frequency in HeLa cells without inducing the chlamydial persistence/stress response, as ascertained by electron microscopy. Irradiation of host cells (HeLa, Vero neither affected cell viability nor induced any molecular markers of cytotoxicity as investigated by Alamar blue assay and Western blot analysis. Chlamydial infection, irradiation, and the combination of both showed a similar release pattern of a subset of pro-inflammatory cytokines (MIF/GIF, Serpin E1, RANTES, IL-6, IL-8 and chemokines (IL-16, IP-10, ENA-78, MIG, MIP-1α/β from host cells. Initial investigation into the mechanism indicated possible thermal effects on Chlamydia due to irradiation. In summary, we demonstrate a non-chemical reduction of chlamydial infection using the combination

  18. Tuning light concentration inside plasmonic core-shell nanoparticles during laser irradiation

    Science.gov (United States)

    Astafyeva, L. G.; Pustovalov, V. K.; Fritzsche, W.

    2017-09-01

    Computer modeling was carried out of the intensity distributions of optical (laser) radiation with wavelengths in the range of 180-540 nm concentrated inside spherical two-layered core-shell nanoparticles with the core radii in the range 10-30 nm and shell thicknesses range 5-40 nm during irradiation. Different metals and oxides are used for core and shell materials of nanoparticles. Novel effect of light localizing at the nanoscale inside spherical two-layered core-shell NPs has been established on the base of computer calculations in the frame of the theory of diffraction of electromagnetic radiation on multilayer sphere. Light intensity concentrates in shadow hemisphere of core-shell NPs for the selected values of nanoparticle sizes and radiation wavelengths. These results can be applied in nanophotonics for construction of novel plasmonic devices and photonic components, and for different applications of the core-shell nanoparticles.

  19. Reversible Addition-Fragmentation Chain Transfer Polymerization of Acrylonitrile under Irradiation of Blue LED Light

    Directory of Open Access Journals (Sweden)

    Zhicheng Huang

    2016-12-01

    Full Text Available Compared to unhealthy UV or γ-ray and high-energy-consumption thermal external stimuli, the promising light emitting diode (LED external stimulus has some outstanding technological merits such as narrow wavelength distribution, low heat generation and energy consumption, and safety for human beings. In this work, a novel reversible addition-fragmentation transfer (RAFT polymerization system for acrylonitrile (AN was developed under the irradiation of blue LED light at room temperature, using 1,2,3,5-tetrakis(carbazol-9-yl-4,6-dicyanobenzene (4CzIPN as a novel radical initiator and 2-cyanoprop-2-yl-1-dithionaphthalate (CPDN as the typical chain transfer agent. Well-defined polyacrylonitrile (PAN with a controlled molecular weight and narrow molecular weight distribution was successfully synthesized. This strategy may provide another effective method for scientific researchers or the industrial community to synthesize a PAN-based precursor of carbon fibers.

  20. Photodegradation of toluene over TiO(2-x)N(x) under visible light irradiation.

    Science.gov (United States)

    Irokawa, Yoshihiro; Morikawa, Takeshi; Aoki, Koyu; Kosaka, Satoru; Ohwaki, Takeshi; Taga, Yasunori

    2006-03-07

    We report the photooxidation of toluene over nitrogen doped TiO(2) (TiO(2-x)N(x)) under visible light irradiation. The photocatalytic oxidation of toluene in air over TiO(2-x)N(x) powders was studied using diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), gas chromatography (GC), ion chromatography (IC), and gas chromatography mass spectrometry (GC-MS), focusing on the photocatalytic decomposition processes of toluene. Results obtained indicate that toluene, weakly adsorbed on the catalyst surface, is initially photooxidized to benzaldehyde which adsorbs onto the TiO(2-x)N(x) surface more strongly, leading to the formation of ring-opening products such as carboxylic acids and aldehydes. No gaseous intermediates were detected during the photooxidation. Major intermediates adsorbed at the catalyst surface were oxalic acid, (COOH)(2), acetic acid, CH(3)COOH, formic acid, HCOOH, and pyruvic acid, CH(3)COCOOH, whereas more complicated carboxylic species, including propionic acid, CH(3)CH(2)COOH, isovaleric acid, (CH(3))(2)CHCH(2)COOH, and succinic acid, (CH(2)COOH)(2), were also found in the early stage of the photooxidation. These intermediate products were gradually photodegraded to CO(2) and H(2)O under visible light irradiation.

  1. Asymmetric bifurcated halogen bonds.

    Science.gov (United States)

    Novák, Martin; Foroutan-Nejad, Cina; Marek, Radek

    2015-03-07

    Halogen bonding (XB) is being extensively explored for its potential use in advanced materials and drug design. Despite significant progress in describing this interaction by theoretical and experimental methods, the chemical nature remains somewhat elusive, and it seems to vary with the selected system. In this work we present a detailed DFT analysis of three-center asymmetric halogen bond (XB) formed between dihalogen molecules and variously 4-substituted 1,2-dimethoxybenzene. The energy decomposition, orbital, and electron density analyses suggest that the contribution of electrostatic stabilization is comparable with that of non-electrostatic factors. Both terms increase parallel with increasing negative charge of the electron donor molecule in our model systems. Depending on the orientation of the dihalogen molecules, this bifurcated interaction may be classified as 'σ-hole - lone pair' or 'σ-hole - π' halogen bonds. Arrangement of the XB investigated here deviates significantly from a recent IUPAC definition of XB and, in analogy to the hydrogen bonding, the term bifurcated halogen bond (BXB) seems to be appropriate for this type of interaction.

  2. Chronic effects of light irradiated from LED on the growth performance and endocrine properties of barfin flounder Verasper moseri.

    Science.gov (United States)

    Takahashi, Akiyoshi; Kasagi, Satoshi; Murakami, Naoto; Furufuji, Sumihisa; Kikuchi, Shigeto; Mizusawa, Kanta; Andoh, Tadashi

    2016-06-01

    We investigated the effects of specific wavelengths of light on the growth of barfin flounder. The fish, reared in white tanks in a dark room, were irradiated with light from light-emitting diodes (LEDs) with peak wavelengths of 464nm (blue), 518nm (green), and 635nm (red) under a controlled photoperiod (10.5:13.5, light-dark cycle; 06:00-16:30, light). Fish were reared for four weeks in three independent experiments at three different water temperatures (averages of 14.9°C, 8.6°C, and 6.6°C). The fish irradiated with blue and green light had higher specific growth rates (% body weight⋅day(-1)) than fish irradiated with red light. Notably, green light had the greatest effect on growth among the three light wavelengths at 6.6°C. In the brains of fish reared at 6.6°C, the amounts of melanin-concentrating hormone 1 mRNA under green light were lower than those under red light, and amounts of proopiomelanocortin-C mRNA under blue and green light were higher than those under red light. No differences were observed for other neuropeptides tested. In the pituitary, no difference was observed in growth hormone mRNA content. In plasma, higher levels of insulin and insulin-like growth factor-I were observed in fish under green light than those of fish under red light. These results suggest that the endocrine systems of barfin flounder are modulated by a specific wavelength of light that stimulates somatic growth. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Assessment of fungal viability after long-wave ultraviolet light irradiation combined with riboflavin administration.

    Science.gov (United States)

    Kashiwabuchi, Renata T; Carvalho, Fabio R S; Khan, Yasin A; Hirai, Flavio; Campos, Mauro S; McDonnell, Peter J

    2013-02-01

    Corneal collagen cross-linking (CXL), a technique that combines riboflavin administration with long-wave ultraviolet light irradiation, was primarily developed to increase the biomechanical strength of collagen fibrils of the cornea to avoid the progression of keratoconus. Recently, this method has been proposed to treat selected cases of infectious keratitis. To test the protocol used for progressive keratoconus in infectious keratitis, Candida albicans, and Fusarium solani, strains were exposed to irradiation using a wavelength of 365 nm at a power density of 3 mW/cm(2) for 30 min in the presence of riboflavin photosensitizer. All experiments were performed in triplicate. Qualitative and quantitative measurements of fungal viability used plate cultures and an automated trypan blue dye exclusion method respectively. Fungal cell diameter was also assessed in all groups. Statistical analyses were performed using the triplicate values of each experimental condition. Experimental findings of photodynamic therapy applied to the cell inactivation of both yeasts and filamentous fungi were compared with control groups. Qualitative results were corroborated with quantitative findings which showed no statistical significance between challenged samples (experimental groups) and the control group (p-value = 1). In comparison with a control group of live cells, statistical significance was observed when riboflavin solution alone had an effect on the morphologic size of filamentous fungi, while ultraviolet light irradiation alone showed a slight decrease in the cell structure of C. albicans. The impact of long-wave ultraviolet combined with riboflavin photosensitizer showed no antifungal effect on C. albicans and F. solani. The significant decrease in cell morphology of both filamentous fungi and yeasts submitted to photosensitizing riboflavin and exposure to ultraviolet light, respectively, may be promising in the development and standardization of alternatives for fungal cell

  4. Quantitative estimation of UV light dose concomitant to irradiation with ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Petin, Vladislav G.; Morozov, Ivan I. [Biophysical Laboratory, Medical Radiological Research Center, 249036 Obninsk, Kaluga Region (Russian Federation); Kim, Jin Kyu, E-mail: jkkim@kaeri.re.k [Korea Atomic Energy Research Institute, Advanced Radiation Technology Institute, Jeongeup 580-185 (Korea, Republic of); Semkina, Maria A. [Biophysical Laboratory, Medical Radiological Research Center, 249036 Obninsk, Kaluga Region (Russian Federation)

    2011-01-15

    A simple mathematical model for biological estimation of UV light dose concomitant to ionizing radiation was suggested. This approach was applied to determine the dependency of equivalent UV light dose accompanied by 100 Gy of ionizing radiation on energy of sparsely ionizing radiation and on volume of the exposed cell suspension. It was revealed that the relative excitation contribution to the total lethal effect and the value of UV dose was greatly increased with an increase in energy of ionizing radiation and volume of irradiated suspensions. It is concluded that these observations are in agreement with the supposition that Cerenkov emission is responsible for the production of UV light damage and the phenomenon of photoreactivation observed after ionizing exposure of bacterial and yeast cells hypersensitive to UV light. A possible synergistic interaction of the damages produced by ionizations and excitations as well as a probable participation of UV component of ionizing radiation in the mechanism of hormesis and adaptive response observed after ionizing radiation exposure is discussed.

  5. Light Irradiation And Response Of The Living Body - Effect Of Pain Relief And Promotion Of Wound Healing -

    Science.gov (United States)

    Taguchi, Yoshio; Kurokawa, Yoshimochi; Ohara, Itaru; Ueki, Hamaichi; Inaba, Humio

    1989-09-01

    The first report of laser irradiation for wound healing was done by Mester, E., et al. in 1968. From their reports, we can get many knowledges and suggestions as for laser irradiation. At that time he used ruby laser (694.3 nm wave length) for surgical wounds and burns on the back skin of mice. The condition of irradiation was studied with energy density between 0.5-10 J/cm2 twice a week. As a result, they noticed 1 J/cm2 irradiation was effective for those wounds. After a few experimental reports, they published their clinical studies in 1975. Clinically, they used He-Ne laser (632.8 nm wave length) irradiation. Human leg ulcers due to peripheral circulatory disturbance were treated with energy density of 4 J/cm2 twice a week. And they got good results, obtaining complete healing in two-thirds of the cases. We became strongly stimulated by those reports. We have been studying the effect of light on experimental and clinical wound healing as well as on various kinds of biological phenomena since 1980. Particularly, its effect according to the difference of light has been studied. In October 1982, the first clinical case was tried by Argon laser (514.5 nm wave length) irradiation for therapeutic purpose. A man had a chronic ulcer of the left first toe due to Buerger's disease for 5 months. Surprizingly, on the 14th day after 6 treatments of the light irradiation, his ulcer completely healed. During these treatments, the patient noticed that the pain completely disappeared after 2 treatments. Fifty Argon laser treatments were carried out on clinical cases after these experiences, we reached to a conclusion that light irradiation stimulated something in the injured tissues and lead to good clinical results. Several studies concerning mechanism for these effects i.e. peripheral circulation, histology of granulation, cell proliferation, chemistry and other studies were carried out. From these investigations, peripheral circulation was improved when in those who were

  6. Different PEEK qualities irradiated with light of different wavelengths: Impact on Martens hardness.

    Science.gov (United States)

    Lümkemann, Nina; Eichberger, Marlis; Stawarczyk, Bogna

    2017-09-01

    To assess the impact of irradiation on Martens hardness parameters of different PEEK qualities filled with titanium dioxide (TiO 2 ), namely PEEK/0%, PEEK/20%, and PEEK/>30%. For Martens hardness (HM) measurements, 40 specimens of each PEEK quality were fabricated and air-abraded with 50μm Al 2 O 3 . HM parameters of PEEK specimens were measured initially and stepwise after irradiating for 5, 10, 20, 30, 40, 60, 80, 100, 180, 360 and 540s using light units with different wavelength: Elipar S10 (430-480nm), EyeVolutionMAX (385-390nm+465-470nm), Translux CL (380-500nm) and bre.Lux Power Unit (370-500nm). HM parameters of 10 human teeth were measured initially on enamel and dentin. Data was analysed using 3-way ANOVA with partial eta-squared (η P 2 ) and post-hoc Tuckey-HSD-test (phardness (p30% (197.35±19.9N/mm 2 ), followed by PEEK/20% (191.45±15.49 N/mm 2 ) showed significantly higher values for HM than PEEK/0% (189.55±16.89N/mm 2 ). PEEK/>30% (5.49±0.4kN/mm) and PEEK/20% (5.38±0.26kN/mm 2 ) presented higher indentation modulus (E IT ) than PEEK/0% (4.77±0.36kN/mm 2 ). Irradiated with wavelength of 430-480nm (PEEK/0%: 193.28N/mm 2 , PEEK20%: 198.83N/mm 2 , PEEK/>30%: 200.5N/mm 2 ) indicated higher HM compared to specimens irradiated with 380-500nm (PEEK/0%: 186.63N/mm 2 , PEEK20%: 191.05N/mm 2 , PEEK/>30%: 196.13N/mm 2 ). Irradiation using 430-480nm (PEEK/0%: 4.95kN/mm 2 , PEEK20%: 5.52kN/mm 2 , PEEK/>30%: 5.59kN/mm 2 ) and 370-500nm (PEEK/0%: 4.92kN/mm 2 , PEEK20%: 5.43kN/mm 2 , PEEK/>30%: 5.53kN/mm 2 ) indicated higher E IT values compared to specimens irradiated with 380-500nm (PEEK/0%: 4.72kN/mm 2 , PEEK20%: 5.34kN/mm 2 , PEEK/>30%: 5.47kN/mm 2 ). Duration of irradiation presented no impact on results. Enamel (HM: 2263.6±405.16, E IT : 63.16±19.24) and dentin (HM: 468.2±30.77N/mm 2 , E IT : 14.14±4.59kN/mm 2 ) presented significantly higher HM and E IT than the tested PEEK qualities (p<0.001). Irradiation with different wavelength impacted HM

  7. Evaluation of 660 nm LED light irradiation on the strategies for treating experimental periodontal intrabony defects.

    Science.gov (United States)

    Tao, Chih-Yun; Lee, Ning; Chang, Hao-Chieh; Yang, Connie; Yu, Xin-Hong; Chang, Po-Chun

    2016-08-01

    This study aims to investigate the therapeutic value of 660 nm light-emitting diode (LED) light irradiation on the strategies for treating experimental periodontal intrabony defects in vivo. Large-sized periodontal intrabony defects were created bilaterally on the mesial aspect of the maxillary second molars of 48 Sprague-Dawley rats, and the rats were equally divided into four treatment groups with primary wound intention (n = 6/treatment/time point), including open flap debridement alone (OD), barrier membrane alone (MB), xenograft alone (BG), and xenograft plus barrier membrane (MG). Each group received daily 0 or 10 J/cm(2) LED light irradiation. The animals were sacrificed after 1 or 4 weeks. The treatment outcome was evaluated by gross observation of wound dehiscence and healing, micro-CT imaging for osteogenesis, and histological assessments for inflammatory cell infiltration and periodontal reattachment. With LED light irradiation, the extent of wound dehiscence was reduced, wound closure was accelerated, epithelial downgrowth was prevented, inflammation was reduced, and periodontal reattachment was promoted in all treatment strategies. Significant reduction of inflammation with LED light irradiation was noted at 1 week in the groups BG and MG (p LED light accelerates mucoperiosteal flap healing and periodontal reattachment. However, the enhancement of osteogenesis appeared to be limited while simultaneously treating with a barrier membrane or xenograft.

  8. The Light-Induced FOS Response in Melanopsin Expressing HEK-293 Cells is Correlated with Melanopsin Quantity and Dependent on Light Duration and Irradiance

    DEFF Research Database (Denmark)

    Georg, Birgitte; Rask, Lene; Hannibal, Jens

    2014-01-01

    after light resulted in reduction of the response compared to exposure to light solely showing dependency on continuous light. Increasing irradiances of blue light (480 nm) up to 10(11) quanta cm(-2) s(-1) elicited steep increases in FOS mRNA, while increases between 10(12) and 5 × 10(13) quanta cm(-2......We established a cell line (HEK-hMel) expressing melanopsin in a tetracycline dependent manner to elucidate new aspects of melanopsin's light response. Different light stimuli were evaluated using FOS expression as response parameter. Immunoblotting was used to evaluate expression of melanopsin......) s(-1) resulted in equally high FOS expression. The HEK-hMel cells were used to characterize facets of melanopsin's light-induced FOS response not approachable in vivo. Novel information such as dependency of the FOS response on both melanopsin amount and light intensity in addition to a detailed...

  9. SiO2 Etching Yield Measurements by CF3 Ion Beam Injections Superposed with Light Irradiation

    Science.gov (United States)

    Ikuse, Kazumasa; Yoshimura, Satoru; Takizawa, Toshifumi; Karahashi, Kazuhiro; Kiuchi, Masato; Hamaguchi, Satoshi

    Etching yields of SiO2 by CF3 ion beam injections with or without simultaneous light irradiation have been measured by a low-energy mass-selected ion beam system. A Xe Lamp, an L2D2 lamp, an Ar ICP (inductively coupled plasma) or a VUV (Vacuum Ultraviolet) Lamp was used separately as the light source. The etching yield is the ratio of the number of incident ions to that of removed atoms. The obtained SiO2 etching yields by simultaneous irradiation of CF3 ions and photons from the light source were smaller than those by ion beam irradiation only. This difference in etching yields may be caused by modification of CFx polymer formation on the substrate surface during the beam etching process.

  10. Dissipative structure in the photo-induced phase under steady light irradiation in the spin crossover complex.

    Science.gov (United States)

    Nishihara, Taishi; Bousseksou, Azzdine; Tanaka, Koichiro

    2013-12-16

    We report the spatial and temporal dynamics of the photo-induced phase in the iron (II) spin crossover complex Fe(ptz)(6)(BF(4))(2) studied by image measurement under steady light irradiation and transient absorption measurement. The dynamic factors are derived from the spatial and temporal fluctuation of the image in the steady state under light irradiation between 65 and 100 K. The dynamic factors clearly indicate that the fluctuation has a resonant frequency that strongly depends on the temperature, and is proportional to the relaxation rate of the photo-induced phase. This oscillation of the speckle pattern under steady light irradiation is ascribed to the nonlinear interaction between the spin state and the lattice volume at the surface.

  11. Effectiveness of composite resin polymerization using light-emitting diodes (LEDs or halogen-based light-curing units Efetividade de polimerização de uma resina composta fotopolimerizada por diodos emissores de luz (LEDs ou luz halógena

    Directory of Open Access Journals (Sweden)

    Bianca Micali

    2004-09-01

    Full Text Available The clinical performance of composite resins is greatly influenced by the quality of the light-curing unit used. The aim of this study was to compare the efficiency of a commercial light-emitting diode (LED with that of a halogen-based light-curing unit by means of dye penetration of a micro hybrid composite resin. The composite resin evaluated was Filtek Z250 (3M Dental. The composite was filled into acrylic moulds that were randomly polymerized for 40 seconds by each of the light-emitting systems: light-emitting diode Ultraled (Dabi Atlante or halogen light Degulux (Degussa Hüls curing units. Immediately after polymerization, each specimen was individually immersed in 1 ml of 2% methylene blue solution at 37°C ± 2°C. After 24 hours, the specimens were rinsed under running distilled water for 1 minute and stored at 37°C ± 2°C at relative humidity for 24 hours. The composite resins were removed from the moulds and individually triturated before being immersed in new test tubes containing 1 ml of absolute alcohol for 24 hours. The solutions were filtered and centrifuged for 3 minutes at 4,000 rpm and the supernatant was used to determine absorbance in a spectrophotometer at 590 nm. To verify the differences between groups polymerized by LED or halogen light t-test was applied. No significant differences were found between composite resins light-cured by LED or halogen light-curing unit (p > 0.05. The commercially LED-based light-curing unit is as effective to polymerize hybrid composite resins as the halogen-based unit.A longevidade clínica das resinas compostas é grandemente influenciada pela qualidade do aparelho fotopolimerizador utilizado. O objetivo deste trabalho foi comparar a eficácia de um aparelho fotopolimerizador de diodos emissores de luz e a de um de luz halógena através do grau de penetração de um corante em uma resina composta micro-híbrida. A resina composta utilizada (Filtek Z250/3M Dental foi inserida em matrizes

  12. Enhanced Photoactivity of Fe + N Codoped Anatase-Rutile Nanowire Film under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Kewei Li

    2012-01-01

    Full Text Available Rutile-anatase phase mixed codoped TiO2 nanowires were designed and prepared by a two-step anodic oxidation method. The results of X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy confirm that the prepared codoped TiO2 nanowires exhibit intimately contacted anatase-rutile heterostructure with the rutile content of 21.89%. The X-ray photoelectron spectroscopy measurements show that nitrogen and iron atoms are incorporated into the titania oxide lattice, and the UV-visible absorption spectra show that the codoping of iron and nitrogen atoms could extend the absorption to visible light region. The photocatalytic activities of all the samples were evaluated by photocatalytic degradation of methylene blue under visible light irradiation. The codoped sample achieves the best response to visible light and the highest photocatalytic activities. The enhancement of photocatalytic activity for codoped sample should be ascribed to the synergistic effects of codoped nitrogen and iron ions and the anatase-rutile heterostructure.

  13. New ZnO@Cardanol Porphyrin Composite Nanomaterials with Enhanced Photocatalytic Capability under Solar Light Irradiation

    Directory of Open Access Journals (Sweden)

    Viviane Gomes Pereira Ribeiro

    2017-09-01

    Full Text Available This work describes the synthesis, characterization, and photocatalytic activity of new composite nanomaterials based on ZnO nanostructures impregnated by lipophlilic porphyrins derived from cashew nut shell liquid (CNSL. The obtained nanomaterials were characterized by X-ray diffraction (XRD, UV-Vis diffuse reflectance spectroscopy (DRS, Fourier transform infrared spectroscopy (FT-IR, transmission electron microscopy (TEM, and steady-state photoluminescence spectra (PL. The results confirm nanostructures showing average diameter of 55 nm and an improved absorption in the visible region. Further, the FTIR analysis proved the existence of non-covalent interactions between the porphyrin molecules and ZnO. The photocatalytic activity of prepared photocatalysts was investigated by degradation of rhodamine B (RhB in aqueous solution under visible light irradiation and natural sunlight. It was demonstrated that the photocatalytic activity increases in the presence of the porphyrins and, also, depends on the irradiation source. The development of composite photocatalysts based on porphyrins derived from CNSL provides an alternative approach to eliminate efficiently toxic wastes from water under ambient conditions.

  14. New ZnO@Cardanol Porphyrin Composite Nanomaterials with Enhanced Photocatalytic Capability under Solar Light Irradiation.

    Science.gov (United States)

    Ribeiro, Viviane Gomes Pereira; Marcelo, Ana Maria Pereira; da Silva, Kássia Teixeira; da Silva, Fernando Luiz Firmino; Mota, João Paulo Ferreira; do Nascimento, João Paulo Costa; Sombra, Antonio Sérgio Bezerra; Clemente, Claudenilson da Silva; Mele, Giuseppe; Carbone, Luigi; Mazzetto, Selma Elaine

    2017-09-21

    This work describes the synthesis, characterization, and photocatalytic activity of new composite nanomaterials based on ZnO nanostructures impregnated by lipophlilic porphyrins derived from cashew nut shell liquid (CNSL). The obtained nanomaterials were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and steady-state photoluminescence spectra (PL). The results confirm nanostructures showing average diameter of 55 nm and an improved absorption in the visible region. Further, the FTIR analysis proved the existence of non-covalent interactions between the porphyrin molecules and ZnO. The photocatalytic activity of prepared photocatalysts was investigated by degradation of rhodamine B (RhB) in aqueous solution under visible light irradiation and natural sunlight. It was demonstrated that the photocatalytic activity increases in the presence of the porphyrins and, also, depends on the irradiation source. The development of composite photocatalysts based on porphyrins derived from CNSL provides an alternative approach to eliminate efficiently toxic wastes from water under ambient conditions.

  15. New ZnO@Cardanol Porphyrin Composite Nanomaterials with Enhanced Photocatalytic Capability under Solar Light Irradiation

    Science.gov (United States)

    Ribeiro, Viviane Gomes Pereira; Marcelo, Ana Maria Pereira; da Silva, Kássia Teixeira; da Silva, Fernando Luiz Firmino; Mota, João Paulo Ferreira; do Nascimento, João Paulo Costa; Sombra, Antonio Sérgio Bezerra; Clemente, Claudenilson da Silva; Mazzetto, Selma Elaine

    2017-01-01

    This work describes the synthesis, characterization, and photocatalytic activity of new composite nanomaterials based on ZnO nanostructures impregnated by lipophlilic porphyrins derived from cashew nut shell liquid (CNSL). The obtained nanomaterials were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and steady-state photoluminescence spectra (PL). The results confirm nanostructures showing average diameter of 55 nm and an improved absorption in the visible region. Further, the FTIR analysis proved the existence of non-covalent interactions between the porphyrin molecules and ZnO. The photocatalytic activity of prepared photocatalysts was investigated by degradation of rhodamine B (RhB) in aqueous solution under visible light irradiation and natural sunlight. It was demonstrated that the photocatalytic activity increases in the presence of the porphyrins and, also, depends on the irradiation source. The development of composite photocatalysts based on porphyrins derived from CNSL provides an alternative approach to eliminate efficiently toxic wastes from water under ambient conditions. PMID:28934117

  16. Light transmission through all-ceramic dental materials: a pilot study.

    Science.gov (United States)

    Rasetto, Flavio H; Driscoll, Carl F; Prestipino, Vince; Masri, Radi; von Fraunhofer, Joseph Anthony

    2004-05-01

    Statement of problem Light transmission through veneers affects the degree of polymerization of light-polymerized resin luting agents. Light transmission through different all-ceramic veneers when irradiated by 3 types of light-polymerization units was measured to evaluate the degree of polymerization. Material and methods The power outputs from a conventional halogen (3M Unitek), a plasma arc (Apollo 95E), and a high-intensity halogen (Kreativ Kuring Light Model 2000) light were measured by a radiometer. The light intensity (mW/cm(2) ) from these units was also measured after transmission through 0.25-, 0.40-, and 0.60-mm-thick Procera copings and through 1-mm-thick disks of feldspathic porcelain (Ceramco II), aluminous porcelain (Vitadur Alpha), and a castable pressed ceramic (IPS Empress). Two disks of each material were fabricated by a commercial laboratory in accordance with the manufacturers' recommendations. The light transmissions through these materials were compared with those through Procera-aluminous porcelain combinations. These disks were fabricated by applying appropriate thicknesses of aluminous porcelain (AllCeram). Light intensities were subjected to ANOVA and post hoc Scheffé tests at a priori alpha=.05. Intensities of light from 3 polymerization units, conventional halogen light, high-intensity halogen light, and plasma arc, were 660, 1050, and 2475 mW/cm,(2) respectively, and these together with the ceramic veneer thickness dictated the light transmission through veneers. Mean values (+/-SD) of light transmission through Procera copings for thicknesses of 0.25, 0.40 and 0.60 mm, respectively, were as follows: Apollo plasma arc (1083 +/- 117, 843 +/- 59, and 593 +/- 132); Kreativ high-intensity halogen (425 +/- 41, 345 +/- 74, and 256 +/- 79); 3M Unitek halogen (270 +/- 102, 230 +/- 48, and 180 +/- 113). Comparable transmissions occurred with the other ceramics. Only the plasma arc and the high-intensity halogen polymerization units emitted

  17. Noninvasive photoacoustic measurement of absorption coefficient using internal light irradiation of cylindrical diffusing fiber

    Science.gov (United States)

    Peng, Dong-qing; Zhu, Li-li; Li, Zhi-fang; Li, Hui

    2017-09-01

    Absorption coefficient of biological tissue is an important parameter in biomedicine, but its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique and internal light irradiation of cylindrical diffusing fiber (CDF) to quantify the target optical absorption coefficient. Absorption coefficients for ink absorbers are firstly determined through photoacoustic and spectrophotometric measurements at the same excitation, which demonstrates the feasibility of this method. Also, the optical absorption coefficients of ink absorbers with several concentrations are measured. Finally, the two-dimensional scanning photoacoustic image is obtained. Optical absorption coefficient measurement and simultaneous photoacoustic imaging of absorber non-invasively are the typical characteristics of the method. This method can play a significant role for non-invasive determination of blood oxygen saturation, the absorption-based imaging and therapy.

  18. Enhancement of photocatalytic property on ZnS/MoS2 composite under visible light irradiation

    Directory of Open Access Journals (Sweden)

    Cheng Jiushan

    2017-01-01

    Full Text Available In this paper, the composite ZnS/MoS2 was obtained via two steps including solvothermal methods. The as-synthesized sample was characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and UV-Vis. diffuse reflectance spectra (DRS. The photocatalytic activity of the product was evaluated through photocatalytic degradation of Rhodamine B (Rh B under UV-Vis. light irradiation; the electrical conductivity of ZnS/MoS2 composites was significantly improved compared to ZnS, MoS2, respectively. The results showed that the ZnS/MoS2 composite photocatalyst possesses better photocatalytic activity in degrading Rh B than the single ZnS or the single MoS2. The better photocatalytic properties may be due to the synergetic effect of two semiconductors, because of which electrons and holes were separated effectively. And its specific microstructure played an active role in evaluating photocatalytic performance.

  19. PANI/NaTaO3 composite photocatalyst for enhanced hydrogen generation under UV light irradiation

    Directory of Open Access Journals (Sweden)

    Zielińska Beata

    2017-09-01

    Full Text Available A PANI/NaTaO3 composite was successfully synthesized by an oxidative polymerization of aniline monomer in hydrochloric acid solution containing sodium tantalate. NaTaO3 at a monoclinic structure was produced via hydrothermal method. The photocatalytic activities of the unmodified NaTaO3 and PANI/NaTaO3 were evaluated for hydrogen generation from an aqueous HCOOH solution and under UV light irradiation. The results showed that the evolution rate of H2 increased significantly when NaTaO3 was modified with PANI. The enhancement of the photocatalytic activity of PANI/NaTaO3 composite was ascribed to the effective charge transfer and separation between NaTaO3 and PANI, which reduced their recombination. This indicates that PANI modification of tantalate photocatalysts may open up a new way to prepare highly efficient catalytic materials for H2 generation.

  20. Photodegradation of methyl orange with PANI-modified BiOCl photocatalyst under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qizhao, E-mail: qizhaosjtu@gmail.com [College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Key Laboratory of Eco-Environment-Related Polymer Materials, Ministry of Education of China, Key Laboratory of Gansu Polymer Materials, Lanzhou 730070 (China); Hui, Juan; Li, Jiajia; Cai, Yuxia; Yin, Shuqun [College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Wang, Fangping, E-mail: wangfplz@163.com [College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Su, Bitao [College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2013-10-15

    Photocatalyst BiOCl modified by polyaniline (PANI/BiOCl) was synthesized via a facile chemisorptions method. X-ray diffraction (XRD), Scanning electron microscopy (SEM) and UV–vis diffuse reflectance spectroscopy (DRS) were employed to study the phase structure, morphology and optical properties of the samples. The results showed that the PANI increased absorption intensity and absorption bands of the pure BiOCl. Photodegradation of methyl orange (MO) on the samples were investigated under visible light irradiation and 7 wt.% PANI/BiOCl composite showed the highest photocatalytic activity. The enhanced photocatalytic performance could be attributed to PANI/BiOCl composites and the synergistic effect between PANI and BiOCl. According to experimental results, the possible photocatalytic mechanism of the PANI/BiOCl photocatalysts was proposed.

  1. Group III-nitride nanowire structures for photocatalytic hydrogen evolution under visible light irradiation

    Directory of Open Access Journals (Sweden)

    Faqrul A. Chowdhury

    2015-10-01

    Full Text Available The performance of photochemical water splitting over the emerging nanostructured photocatalysts is often constrained by their surface electronic properties, which can lead to imbalance in redox reactions, reduced efficiency, and poor stability. We have investigated the impact of surface charge properties on the photocatalytic activity of InGaN nanowires. By optimizing the surface charge properties through controlled p-type dopant (Mg incorporation, we have demonstrated an apparent quantum efficiency of ∼17.1% and ∼12.3% for InGaN nanowire arrays under visible light irradiation (400 nm–490 nm in aqueous methanol and in the overall neutral-pH water splitting reaction, respectively.

  2. Hydrogen production using zinc-doped carbon nitride catalyst irradiated with visible light

    Directory of Open Access Journals (Sweden)

    Bing Yue, Qiuye Li, Hideo Iwai, Tetsuya Kako and Jinhua Ye

    2011-01-01

    Full Text Available Recently, graphitic carbon nitride (g-C3N4 has been investigated as a photocatalyst for water splitting and organic dye degradation. In this study, we have developed a simple soft-chemical method of doping Zn into g-C3N4 to prepare a metal-containing carbon nitride. The doping was confirmed by x-ray photoelectron spectroscopy, and diffusion reflectance spectra revealed a significant red shift in the absorption edge of Zn/g-C3N4. This hybrid material shows high photocatalytic activity and good stability for hydrogen evolution from an aqueous methanol solution under visible light irradiation (λ≥420 nm. The hydrogen evolution rate was more than 10 times higher for a 10%-Zn/g-C3N4 sample (59.5 μmol h−1 than for pure g-C3N4. The maximum quantum yield was 3.2% at 420 nm.

  3. Aniline chlorination by in situ formed Ag-Cl complexes under simulated solar light irradiation.

    Science.gov (United States)

    Hu, Xuefeng; Wang, Xiaowen; Dong, Liuliu; Chang, Fei; Luo, Yongming

    2015-01-01

    Ag speciation in a chloride medium was dependent upon the Cl/Ag ratio after releasing into surface water. In this study, the photoreaction of in situ formed Ag-Cl species and their effects on aniline photochlorination were systematically investigated. Our results suggested that formation of chloroaniline was strongly relevant to the Cl/Ag ratio and could be interpreted using the thermodynamically expected speciation of Ag in the presence of Cl-. AgCl was the main species responsible for the photochlorination of aniline. Both photoinduced hole and •OH drove the oxidation of Cl- to radical •Cl, which promoted the chlorination of aniline. Ag0 formation was observed from the surface plasmon resonance absorption during AgCl photoreaction. This study revealed that Ag+ released into Cl--containing water may result in the formation of chlorinated intermediates of organic compounds under solar light irradiation.

  4. Plasmonic phototherapy using gold nanospheres and gold nanorods irradiated with light-emitting diodes

    Science.gov (United States)

    Poorani, Gananathan; Rao, Aruna Prakasa; Singaravelu, Ganesan; Manickam, Elanchezhiyan

    2016-04-01

    Gold nanoparticles (GNPs) provide different modes of therapeutic responses in cells depending on their size and shape. We have studied two modifications of GNPs exhibiting surface plasmon resonances (SPRs) with phototherapeutic effects in nonmalignant Vero and malignant HeLa cell lines. The cells were treated with 30-nm-size gold nanospheres (GNSs) (having SPR at a wavelength of 530 nm) and with gold nanorods (GNRs) (having SPR at 630 nm). The plasmonic phototherapy effect in cells was provided by irradiating them with green and red light-emitting diodes (LEDs). The cytotoxicities of GNPs were determined by MTT assay. Both the GNSs and GNRs were found to be biocompatible and have efficient phototherapeutic activity with LEDs.

  5. Tissue damage after single high-dose intraoperative irradiation of the canine liver : Evaluation in time by means of radionuclide imaging and light microscopy

    NARCIS (Netherlands)

    Cromheecke, M; Piers, BA; Beekhuis, H; ter Veen, H; Sluiter, WJ; Hoekstra, HJ

    2000-01-01

    To establish the tolerance of liver tissue to single high-dose intraoperative irradiation, the histopathological changes in the canine liver after single high-dose intraoperative irradiation were investigated by means of radionuclide imaging and light microscopy, Intraoperative irradiation at doses

  6. On different photodecomposition behaviors of rhodamine B on laponite and montmorillonite clay under visible light irradiation

    KAUST Repository

    Wang, Peng

    2013-12-11

    In this study, laponite and montmorillonite clays were found to be able to decompose rhodamine B upon visible light irradiation (λ>420nm). Very interestingly, it was found that rhodamine B on laponite underwent a stepwise N-deethylation and its decomposition was terminated once rhodamine 110, as a decomposition product, was formed, whereas the same phenomenon was not observed for rhodamine B on montmorillonite, whose decomposition involved chromophore destruction. Mechanistic study revealed that the different photodecomposition behaviors of rhodamine B on laponite and montmorillonite were attributed to the oxidation by different reactive oxygen species, with laponite involving HO2/O2- while montmorillonite involving OH. It was also found that the degradation pathway of rhodamine B on laponite switched from N-deethylation to chromophore destruction when solution pH was changed from 7.0 to 3.0, which was attributed to a much higher fraction of HO2 relative to O2- under pH 3.0 than under pH 7.0. Based on the results, a mechanism of rhodamine dye decomposition on clay under visible light was proposed, involving the clay as an electron acceptor, electron relay between the adsorbed dye molecules and oxygen molecules, and subsequent reactions between the generated dye radical cations and different reactive oxygen species. The results of this study shed light on how to best utilize visible light for organic pollutant degradation on clays within engineered treatment systems as well as on many of naturally occurring pollutant degradation processes in soils and air involving clay. © 2013 King Saud University.

  7. Chlorophyll degradation in aqueous mediums induced by light and UV-B irradiation: An UHPLC-ESI-MS study

    Science.gov (United States)

    Petrović, Sanja; Zvezdanović, Jelena; Marković, Dejan

    2017-12-01

    Irreversible chlorophyll degradation induced by continuous white light illumination and UV-B irradiation in the aqueous mediums (with 10%, 30% and 50% of methanol) was investigated using the ultrahigh liquid chromatography coupled with diode array and electrospray ionization mass spectrometry detectors (UHPLC-DAD-ESIMS). The degradation was governed by energy input of photons: higher energy of UV-B irradiation induced faster chlorophyll degradation and accordingly faster products formation in comparison to the white light treatment. Main light- or/and UV-B-induced products of chlorophyll in the aqueous mediums were hydroxy-pheophytin a, pheophytin a and hydroxy-lactone-pheophytin a, accompanied with the corresponding epimers. Chlorophylls aggregation dominant in the aqueous medium with the highest methanol content (50%) play a protective role against the UV-B radiation and white light illumination.

  8. Halogen Chemistry in the CMAQ Model

    Science.gov (United States)

    Halogens (iodine and bromine) emitted from oceans alter atmospheric chemistry and influence atmospheric ozone mixing ratio. We previously incorporated a representation of detailed halogen chemistry and emissions of organic and inorganic halogen species into the hemispheric Commun...

  9. Effect of white light irradiation on the endogenous growth regulators content in seeds and seedlings of pine (Pinus silvestris L.

    Directory of Open Access Journals (Sweden)

    J. Kopcewicz

    2015-01-01

    Full Text Available The increase of gibberellin content and decrease of amount of inhibitors in light irradiated pine seedlings were found. It was also stated that stimulating effect of light on pine seeds germination is correlated with the increase of gibberellin and simultaneous decrease of the inhibitor content. The inhibitor isolated from pine seeds proved to be a compound similar in some properties to abscisic acid.

  10. Comparative efficacy of microwave, visible light and ultrasound irradiation for green synthesis of dihydropyrimidinones in fruit juice medium

    Science.gov (United States)

    Pramanik, Tanay; Padan, Simarjit Kaur; Gupta, Richa; Bedi, Pooja; Singh, Gurinderpal

    2017-07-01

    Dihydropyrimidinones (DHPM) were synthesized via multi component condensation reaction employing urea, ethyl acetoacetate and aromatic aldehydes as reactants. Apple, pomegranate, grape juice were used individually as biodegradable, eco friendly, and green reaction medium whereas microwave, visible light and ultrasound irradiation were applied individually as green source of energy for carrying out the aforesaid reactions. It was observed that the reactions under microwave irradiation were taking minimum time to go for completion whereas the reactions under ultrasound and visible light irradiation were taking approximately same time duration to form products. This is the first of its kind study where the three different reaction methodologies based on three different sources of green energies were compared with each other for their effectiveness and efficiency towards multi component condensation reactions.

  11. TiO2 film/Cu2O microgrid heterojunction with photocatalytic activity under solar light irradiation.

    Science.gov (United States)

    Zhang, Junying; Zhu, Hailing; Zheng, Shukai; Pan, Feng; Wang, Tianmin

    2009-10-01

    Coupling a narrow-band-gap semiconductor with TiO(2) is an effective method to produce photocatalysts that work under UV-vis light irradiation. Usually photocatalytic coupled-semiconductors exist mainly as powders, and photocatalytic activity is only favored when a small loading amount of narrow-band-gap semiconductor is used. Here we propose a heavy-loading photocatalyst configuration in which 51% of the surface of the TiO(2) film is covered by a Cu(2)O microgrid. The coupled system shows higher photocatalytic activity under solar light irradiation than TiO(2) and Cu(2)O films. This improved performance is due to the efficient charge transfer between the two phases and the similar opportunity each has to be exposed to irradiation and adsorbates.

  12. The bactericidal effect of carbon nanotube/agar composites irradiated with near-infrared light on Streptococcus mutans

    Energy Technology Data Exchange (ETDEWEB)

    Akasaka, Tsukasa, E-mail: akasaka@den.hokudai.ac.jp [Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-ku, Sapporo 060-8586 (Japan); Matsuoka, Makoto [Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-ku, Sapporo 060-8586 (Japan); Hashimoto, Takeshi [Meijo Nano Carbon Co. Ltd., Otsubashi bldg. 4F, 3-4-10 Marunouchi, Naka-ku, Nagoya 460-0002 (Japan); Abe, Shigeaki; Uo, Motohiro; Watari, Fumio [Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-ku, Sapporo 060-8586 (Japan)

    2010-10-15

    Dental caries are mainly associated with oral pathogens, and Streptococcus mutans is a primary cariogenic organism. Many methods have been established to eliminate S. mutans from the oral cavity. This study aimed to evaluate the effect of carbon nanotube (CNT)/agar composites irradiated with near-infrared (NIR) light on S. mutans, as a potential photothermal antimicrobial nanotherapy. A colony-forming unit assay clearly showed that CNT/agar composites attain bactericidal activity after NIR light irradiation; this bactericidal activity is higher than that of graphite (GP)/agar and activated carbon (AC)/agar composites. Furthermore, it was observed that longer irradiation times immobilized S. mutans in the CNT/agar composite.

  13. Halogenation processes of secondary organic aerosol and implications on halogen release mechanisms

    Directory of Open Access Journals (Sweden)

    J. Ofner

    2012-07-01

    Full Text Available Reactive halogen species (RHS, such as X·, X2 and HOX containing X = chlorine and/or bromine, are released by various sources like photo-activated sea-salt aerosol or from salt pans, and salt lakes. Despite many studies of RHS reactions, the potential of RHS reacting with secondary organic aerosol (SOA and organic aerosol derived from biomass-burning (BBOA has been neglected. Such reactions can constitute sources of gaseous organohalogen compounds or halogenated organic matter in the tropospheric boundary layer and can influence physicochemical properties of atmospheric aerosols.

    Model SOA from α-pinene, catechol, and guaiacol was used to study heterogeneous interactions with RHS. Particles were exposed to molecular chlorine and bromine in an aerosol smog-chamber in the presence of UV/VIS irradiation and to RHS, released from simulated natural halogen sources like salt pans. Subsequently, the aerosol was characterized in detail using a variety of physicochemical and spectroscopic methods. Fundamental features were correlated with heterogeneous halogenation, which results in new functional groups (FTIR spectroscopy, changes UV/VIS absorption, chemical composition (ultrahigh resolution mass spectroscopy (ICR-FT/MS, or aerosol size distribution. However, the halogen release mechanisms were also found to be affected by the presence of organic aerosol. Those interaction processes, changing chemical and physical properties of the aerosol are likely to influence e.g. the ability of the aerosol to act as cloud condensation nuclei, its potential to adsorb other gases with low-volatility, or its contribution to radiative forcing and ultimately the Earth's radiation balance.

  14. Chloroplast translocations in Lemna trisulca L. induced by continuous irradiation and by light pulses : Kinetic analysis.

    Science.gov (United States)

    Zurzycki, J; Walczak, T; Gabryś, H; Kajfosz, J

    1983-05-01

    The analytical model describing the steady state position of chloroplasts in dependence of fluence rate as well as the chloroplast response to single strong light pulses has been proposed. The model is based on the following assumptions: 1. Irradiation of the cell generates the state X in the cell membrane region, proportional to the local fluence rate. After switching on the light, the value of X increases exponentially with the time constant of about 3 min. The dark decay of X is also exponential with the same time constant. The level of X controls all kinds of chloroplast arrangements. 2. The state X generates two further states: Y 1 and Y 2, the first of them representing attraction forces for chloroplasts and the second representing repulsion forces. Empirical equations have been found for both Y states. The fluence rate response curve can be described with the use of functions Y 1 and Y 2. 3. The kinetic analysis requires the introduction of two additional functions Z in order to account for delays and time dispersion of the chloroplast movement in response to driving and resistance factors. The computer program for the proposed model was developed and the results of calculations were compared with experimental data (fluence rate response curve and pulse effects) with satisfactory agreement. Initially no attempt was made to ascribe any physical meaning to the postulated states. Some suggestions in this respect are mentioned in the discussion.

  15. Highly efficient photocatalytic hydrogen evolution of graphene/YInO3 nanocomposites under visible light irradiation.

    Science.gov (United States)

    Ding, Jianjun; Yan, Wenhao; Xie, Wei; Sun, Song; Bao, Jun; Gao, Chen

    2014-02-21

    Visible-light-driven hydrogen evolution with high efficiency is important in the current photocatalysis research. Here we report for the first time the design and synthesis of a new graphene-semiconductor nanocomposite consisting of YInO3 nanoparticles and two-dimensional graphene sheets as efficient photocatalysts for hydrogen evolution under visible light irradiation. The graphene/YInO3 nanocomposites were synthesized using a facile solvothermal method in which the formation of graphene and the deposition of YInO3 nanoparticles on the graphene sheets can be achieved simultaneously. The addition of graphene as a cocatalyst can narrow the band gap of YInO3 to visible photon energy and prolong the separation and lifetime of electron-hole pairs by the chemical bonding between YInO3 and graphene. The photocatalytic reaction with this nanocomposite reaches a high H2 evolution rate of 400.4 μmol h(-1) g(-1) when the content of graphene is 0.5 wt%, over 127 and 3.7 times higher than that of pure YInO3 and Pt/YInO3, respectively. This work can provide an effective approach to the fabrication of graphene-based photocatalysts with high performance in the field of energy conversion.

  16. Gold-plasmon enhanced photocatalytic performance of anatase titania nanotubes under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Bingyang [Key Laboratory of Luminescence and Optical Information, Beijing Jiaotong University, Beijing, 100044 (China); He, Dawei, E-mail: dwhe@bjtu.edu.cn [Key Laboratory of Luminescence and Optical Information, Beijing Jiaotong University, Beijing, 100044 (China); Wang, Wenshuo [Institute of Particle Technology, Friedrich-Alexander University Erlangen-Nuremberg, Cauerstrasse 4, D-91058 Erlangen (Germany); Zhuo, Zuliang; Wang, Yongsheng [Key Laboratory of Luminescence and Optical Information, Beijing Jiaotong University, Beijing, 100044 (China)

    2016-02-15

    Highlights: • APTMS/(TNTs-Au) was synthesized using a deposition-precipitation process. • APTMS/(TNTs-Au) showed superior visible light activity for the degradation of methylene blue. • The electromagnetic field distribution at the interface between TNTs and Au NPs were estimated by the 3D finite-difference time domain simulation. • The working mechanism of the photocatalytic activity of APTMS/(TNTs-Au) was illustrated. - Abstract: [3-Aminopropyl]trimethoxysilane-modified titania nanotubes decorated with Au nanoparticles (APTMS/(TNTs-Au)) nanocomposites were synthesized using a deposition-precipitation process. The results showed that Au nanoparticles (NPs) in the metallic state were firmly adhered to the surface of the anatase TNTs. APTMS/(TNTs-Au) exhibited great photocatalytic activities which were evaluated from the degradation rate of methylene blue aqueous solution under visible light irradiation. 3D finite-difference time domain simulation was performed to estimate the electromagnetic field distribution at the interface between TNTs and Au NPs. The visible photocatalytic activity of APTMS/(TNTs-Au) was largely attributed to the surface plasmon absorption of metallic Au NPs, which generated and transferred hot electrons to the CB of TNTs. In addition, the hot electrons on the surface of TNTs also suppressed the radiative electron–hole recombination and consequently enhanced the photocatalytic activity.

  17. A rapid method of estimating the solar irradiance spectra with potential lighting applications

    NARCIS (Netherlands)

    Gao, Y.; Dong, J.; Isabella, O.; Zeman, M.; Zhang, G

    2016-01-01

    Diverse solar irradiance spectra can be observed under different conditions of time, date, location, weather, etc. Since the solar irradiance spectrum is required by certain scientific and engineering applications, obtaining accurate spectral data is essential. Measurements by spectrophotometers are

  18. White Light Demonstration of One Hundred Parts per Billion Irradiance Suppression in Air by New Starshade Occulters

    Science.gov (United States)

    Levinton, Douglas B.; Cash, Webster C.; Gleason, Brian; Kaiser, Michael J.; Levine, Sara A.; Lo, Amy S.; Schindhelm, Eric; Shipley, Ann F.

    2007-01-01

    A new mission concept for the direct imaging of exo-solar planets called the New Worlds Observer (NWO) has been proposed. The concept involves flying a meter-class space telescope in formation with a newly-conceived, specially-shaped, deployable star-occulting shade several meters across at a separation of some tens of thousands of kilometers. The telescope would make its observations from behind the starshade in a volume of high suppression of incident irradiance from the star around which planets orbit. The required level of irradiance suppression created by the starshade for an efficacious mission is of order 0.1 to 10 parts per billion in broadband light. This paper discusses the experimental setup developed to accurately measure the suppression ratio of irradiance produced at the null position behind candidate starshade forms to these levels. It also presents results of broadband measurements which demonstrated suppression levels of just under 100 parts per billion in air using the Sun as a light source. Analytical modeling of spatial irradiance distributions surrounding the null are presented and compared with photographs of irradiance captured in situ behind candidate starshades.

  19. Influence of pre-harvest red light irradiation on main phytochemicals and antioxidant activity of Chinese kale sprouts.

    Science.gov (United States)

    Deng, Mingdan; Qian, Hongmei; Chen, Lili; Sun, Bo; Chang, Jiaqi; Miao, Huiying; Cai, Congxi; Wang, Qiaomei

    2017-05-01

    The effects of pre-harvest red light irradiation on main healthy phytochemicals as well as antioxidant activity of Chinese kale sprouts during postharvest storage were investigated. 6-day-old sprouts were treated by red light for 24h before harvest and sampled for further analysis of nutritional quality on the first, second and third day after harvest. The results indicated that red light exposure notably postponed the degradation of aliphatic, indole, and total glucosinolates during postharvest storage. The vitamin C level was remarkably higher in red light treated sprouts on the first and second day after harvest when compared with the control. In addition, red light treatment also enhanced the accumulation of total phenolics and maintained higher level of antioxidant activity than the control. All above results suggested that pre-harvest red light treatment might provide a new strategy to maintain the nutritive value of Chinese kale sprouts during postharvest storage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. A Comparison Study of New TiO2/PEG Immobilized Techniques Under Normal and Visible Light Irradiations

    Directory of Open Access Journals (Sweden)

    Zaharudin R.

    2016-01-01

    Full Text Available Novel photocatalysts of TiO2 and TiO2/PEG were immobilized using new technique which is double sided adhesive tape (DSAT as a thin layer binder onto glass plate. The photocatalytic activity study of immobilized/TiO2 and immobilized/TiO2/PEG were carried out by irradiating of 36 mg L-1 MB dye in the presence of normal and visible light with rate of decolourization was estimated from aliquot concentration spectrophotometrically. The high photocatalytic activity from immobilized/TiO2/PEG was observed with the rate constants of ca 0.06 and 0.02 min-1 under normal and visible light irradiation respectively. An active photocatalytic activity was observed for immobilized/TiO2/PEG sample while no photocatalytic activity detected under immobilized/TiO2. The high photoactivity was also detected under normal light for immobilized/TiO2/PEG sample. This might be due to the presence of electron conjugate in PEG that acted as electron donor for TiO2 thus increase the photocatalysis process. Moreover, this electron donor is reported to be able to become active under low energy visible light hence the immobilized/TiO2/PEG can perfomed its photoactivity under visible light irradiation.

  1. Light and electron microscopic observation of the active peripheral regions of the keloids following electron ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Hiroshi [Kanazawa Medical univ., Uchinada, Ishikawa (Japan)

    1995-03-01

    The present study was designed to investigate changes in the active peripheral region of keloid before and after irradiation with 4 MeV electrons in 25 patients. Thirteen patients were treated with a daily dose of 5 Gy for consecutive 5 days (a total dose of 25 Gy) one week after total keloid excision and the other 12 were treated conservatively with a weekly dose of 4 Gy 3 times (one course) to a total of 3 courses at intervals of 2 months (a total dose of 36 Gy). Specimens were collected from the active peripheral region of keloids before and after electron irradiation for light and electron microscopy. Light microscopy revealed that the number of mast cells was significantly decreased after electron irradiation, corresponding to the clinical improvement. Electron microscopic findings before irradiation included active fibroblasts containing well-developed rough endoplasmic reticulum, nucleus having sharp indentations towards its center, and immature elastic fibers in the extracellular space. After irradiation, electron microscopy revealed that fibroblasts were less active and the rough endoplasmic reticulum and Golgi apparatus appeared to be undeveloped with many vacuoles. In the extracellular space, elastosis was found. The average diameter of the collagen fibrils in the peripheral region of the keloid tissue was increased. Electron irradiation may correct abnormal wound healing of keloids by suppressing the abnormal production of collagen by fibroblasts. In addition, electron irradiation promote the maturation of the existing extracellular matrix, leading to the formation of a mature scar. Furthermore, the low recurrence rate suggests that the effect of the electrons against keloid tissue is persistent. (N.K.).

  2. Sporicidal performance induced by photocatalytic production of organic peroxide under visible light irradiation

    Science.gov (United States)

    Yamaguchi, Yuichi; Shimodo, Takahito; Chikamori, Noriyasu; Usuki, Sho; Kanai, Yoshihiro; Endo, Takeshi; Katsumata, Ken-Ichi; Terashima, Chiaki; Ikekita, Masahiko; Fujishima, Akira; Suzuki, Tomonori; Sakai, Hideki; Nakata, Kazuya

    2016-09-01

    Bacteria that cause serious food poisoning are known to sporulate under conditions of nutrient and water shortage. The resulting spores have much greater resistance to common sterilization methods, such as heating at 100 °C and exposure to various chemical agents. Because such bacteria cannot be inactivated with typical alcohol disinfectants, peroxyacetic acid (PAA) often is used, but PAA is a harmful agent that can seriously damage human health. Furthermore, concentrated hydrogen peroxide, which is also dangerous, must be used to prepare PAA. Thus, the development of a facile and safe sporicidal disinfectant is strongly required. In this study, we have developed an innovative sporicidal disinfection method that employs the combination of an aqueous ethanol solution, visible light irradiation, and a photocatalyst. We successfully produced a sporicidal disinfectant one hundred times as effective as commercially available PAA, while also resolving the hazards and odor problems associated with PAA. The method presented here can potentially be used as a replacement for the general disinfectants employed in the food and health industries.

  3. Degradation of blue and red inks by Ag/AgCl photocatalyst under UV light irradiation

    Science.gov (United States)

    Daupor, Hasan; Chenea, Asmat

    2017-08-01

    Objective of this research, cubic Ag/AgCl photocatalysts with an average particle size of 500 nm has been successfully synthesized via a modified precipitation reaction between ZrCl4 and AgNO3. Method for analysis, the crystal structure of the product was characterized by X-ray powder diffraction (XRD). The morphology and composition were studied by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV-vis diffuse-reflection spectra (DRS) and so on. The result showed that the optical absorption spectrum exhibited strong absorption in the visible region around 500-600 nm due to surface plasmon resonance (SPR) of metallic silver nanoparticles. SEM micrographs showed that the obtained Ag/AgCl had cubic morphology and appeared on the porous surface as the cubic cage morphology. As a result, this porous surface also positively affected the photocatalytic reaction. The photocatalytic activity of the obtained product was evaluated by the photodegradation of blue and red ink solutions under UV light irradiation, and it was interestingly, discovered that AgCl could degrade 0.25% and 0.10% in 7 hours for blue and red inks solution respectively, Which were higher than of commercial AgCl. The result suggested that the morphology of Ag/AgCl strongly affected their photocatalytic activities. O2-, OH- reaction. radicals and Cl° atom are main species during photocatalytic reaction.

  4. Photocatalytic Degradation of Methylene Blue under UV Light Irradiation on Prepared Carbonaceous TiO2

    Directory of Open Access Journals (Sweden)

    Zatil Amali Che Ramli

    2014-01-01

    Full Text Available This study involves the investigation of altering the photocatalytic activity of TiO2 using composite materials. Three different forms of modified TiO2, namely, TiO2/activated carbon (AC, TiO2/carbon (C, and TiO2/PANi, were compared. The TiO2/carbon composite was obtained by pyrolysis of TiO2/PANi prepared by in situ polymerization method, while the TiO2/activated carbon (TiO2/AC was obtained after treating TiO2/carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450°C. X-ray powder diffraction (XRD, transmission electron microscopy (TEM, Fourier transform infrared (FTIR, thermogravimetric analysis (TG-DTA, Brunauer-Emmet-Teller (BET, and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO2/AC > TiO2/C > TiO2/PANi > TiO2 (179 > 134 > 54 > 9 m2 g−1. The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples.

  5. Regulation of cellular marker modulated upon irradiation of low power laser light in burn injured mice

    Science.gov (United States)

    Rathnakar, Bharath; Prabhu, Vijendra; Rao, Bola Sadashiva Satish; Chandra, Subhash; Rai, Sharada; Mahato, Krishna Kishore

    2016-12-01

    The present study intends to understand the importance of cellular marker in tissue regeneration regulated upon irradiation of low power laser light in burn inflicted mice. Under anesthetic conditions, the thermal injury was induced on Swiss albino mice of either sex. Following injury, the animals were randomly divided into three groups; i. e., un-illuminated control, the group treated with 5% Povidone iodine (reference standard) and single exposure of 3 J/cm2 (830 nm). Burn tissue samples from each group were excised at day 6 post burn injury upon euthanization and used for histological and immunohistochemical analysis. Haematoxylin and Eosin (H and E) staining was performed on the selected sections to asses proliferation and angiogenesis at day 6 post-injury. For immunohistochemical analysis, tissue sections from all the three treatment groups on day 6 were stained using specific antibody against Proliferating cell nuclear antigen (PCNA). The results of the histological and immunohistochemical analysis showed improved tissue restoration in animals treated with optimal laser influence as compared to un-illuminated controls. The findings of present study clearly demonstrated the beneficial effects of 830 nm laser in burn wound healing and its influence in regulating the cellular marker.

  6. Hair reduction using a new intense pulsed light irradiator and a normal mode ruby laser.

    Science.gov (United States)

    Bjerring, P; Cramers, M; Egekvist, H; Christiansen, K; Troilius, A

    2000-06-01

    The main purpose of this clinical study was to compare the effectiveness of an intense pulsed light irradiator system (IPL) and a normal mode ruby laser for hair removal. Thirty-one patients were treated 3 times with a new IPL system on one side of the chin and neck and with a normal mode ruby laser on the other side. After 6 months, nine of the patients received 3 additional IPL treatments and 11 patients received 3 additional ruby laser treatments. All treatment intervals were 2 months. Hair reduction was measured by hair counts on close-up photographs. Hair reduction was obtained by 93.5% of the patients after 3 IPL treatments and by 54.8% after 3 ruby laser treatments. The average hair count was reduced by 49.3% after IPL treatments and by 21.3% after ruby laser treatments. Three additional IPL treatments following 3 IPL treatments resulted in only 6.6% further hair reduction--in total 55.9%, whereas 3 IPL treatments following 3 ruby laser treatments resulted in an additional 35.5% hair reduction--in total 56.8%. The IPL was found to be 3.94 times more effective than the ruby laser for hair removal. In the chin and neck region, more than 3 treatments with the IPL did not improve the therapeutic result significantly.

  7. Effects of Linear-Polarized Near-Infrared Light Irradiation on Chronic Pain

    Directory of Open Access Journals (Sweden)

    Dong Huang

    2012-01-01

    Full Text Available In order to study the efficacy of linear-polarized near-infrared light irradiation (LPNIR on relieving chronic pain in conjunction with nerve block (NB or local block (LB, a 3-week prospective, randomized, double-blind, controlled study was conducted to evaluate the pre- and post-therapy pain intensity. Visual analogue scales (VASs were measured in all patients before and 6 months after therapy visiting the pain clinic during the period of August 2007 to January 2008. A total of 52 patients with either shoulder periarthritis or myofascial pain syndrome or lateral epicondylitis were randomly assigned into two groups by drawing lots. Patients in Group I were treated with NB or LB plus LPNIR; Group II patients, for their part, were treated with the same procedures as in Group I, but not using LPNIR. In both groups, the pain intensity (VAS score decreased significantly immediately after therapy as compared to therapy. There was a significant difference between the test and control groups immediately after therapy (P<0.05, while no effect 6 months later. No side effects were observed. It is concluded that LPNIR is an effective and safe modality to treat various chronic pains, which has synergic effects with NB or LB.

  8. Probing Photocatalytic Characteristics of Sb-Doped TiO2 under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Lingjing Luo

    2014-01-01

    Full Text Available Sb-doped TiO2 nanoparticle with varied dopant concentrations was synthesized using titanium tetrachloride (TiCl4 and antimony chloride (SbCl3 as the precursors. The properties of Sb-doped TiO2 nanoparticles were characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, fluorescence spectrophotometer, and Uv-vis spectrophotometer. The absorption edge of TiO2 nanoparticles could be extended to visible region after doping with antimony, in contrast to the UV absorption of pure TiO2. The results showed that the photocatalytic activity of Sb-doped TiO2 nanoparticles was much more active than pure TiO2. The 0.1% Sb-doped TiO2 nanoparticles demonstrated the best photocatalytic activity which was better than that of the Degussa P25 under visible light irradiation using terephthalic acid as fluorescent probe. The effects of Sb dopant on the photocatalytic activity and the involved mechanism were extensively investigated in this work as well.

  9. The behavior of active bactericidal and antifungal coating under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Gang; Zhang, Xiaodong; Zhao, Yan; Su, Haijia, E-mail: suhj@mail.buct.edu.cn; Tan, Tianwei

    2014-02-15

    In the present paper, the novel active bactericidal and antifungal coatings (ABAC) have been prepared through the immobilization of Fe-doped TiO{sub 2} (anatase) with chitosan. The characterization of ABAC using optical microscope imaging, SEM, AFM and FTIR shows that the Fe doped TiO{sub 2} is embedded into the chitosan coating with favorable dispersion through the hydrogen bonds interaction between chitosan molecules and TiO{sub 2}. The contact angle measurement demonstrated the hydrophilicity of ABAC (θ = 34.5 ± 4.1°). The bactericidal activity of ABAC has been evaluated by inactivating three different test strains: Escherichia coli, Candida albicans and Aspergillus niger which illustrates the apparently higher bactericidal ability than chitosan, Fe-TiO{sub 2} and chitosan/TiO{sub 2} (pure) under visible light irradiation and its bactericidal activity is lasting for at least 24 h. ABAC showed rapid and efficient antibacterial ability for the three tested strains and its antibacterial ratio in 2 h for E. coli, C. albicans and A. niger was 99.9%, 97.0% and 95.0%, respectively. The prepared chitosan/TiO{sub 2} composite emulsion shows favorable storage stability and can be stored up to 1 year without losing its bactericidal activity. ABAC is a low-cost and eco-friendly antibacterial coating products and promising for domestic, medical and industrial applications.

  10. Histopathological analysis of UV-B irradiated retina by Cavia Coba'ya and with protection of transmission light lambda 550-600 nm.

    Science.gov (United States)

    Vojniković, Bozidar; Vojniković, Davor; Brcić, Luka

    2007-01-01

    In 14 experimental Cavia Coba'ya eyes were irradiated with UV-B light, lambda 312 nm, 25 J/cm2 in 15 minute exposure. Including the transmission of light through optical media: cornea, lens, humor aqueous and vitreous body, and pupil surface of 7 mm2, we can calculate that in these conditions retina can be really irradiated with 10 J/cm2. The half number of Cavia Coba'ya was simultaneously irradiated with visible light, lambda of 550-600 nm (1000 Lx). Control group was 5 Cavia Coba'ya. Two months after irradiation, eyes were enucleated and fixed in 4% formaldehyde. Histopathological findings showed alterations of all retinal layers: loss of ganglion cells, axons, reduction of photoreceptors, vacuolar degeneration and hyperplasia of retinal pigment epithelium. In the second group of irradiance, the eyes with visible light lambda 550-600 nm, all retinal alterations were in 50% decreased.

  11. The Effects of Single Pulse and Repetitive (Cumulative) Neodymium and Frequency-Doubled Neodymium Laser Irradiations on Prior Light- and Dark-Adapted Monkey Retinas

    Science.gov (United States)

    1990-12-01

    damage due to single and picosecond 1060 nm laser light pulses. Aviat. Space Environ. Med. 50: 788- 791. SO. Tso, M.O. (1973) Photic maculopathy in...AD_______ THE EFFECTS OF SINGLE PULSE AND REPETITIVE (CUMULATIVE) NEODYMIUM AND FREQUENCY-DOUBLED NEODYMIUM LASER IRRADIATIONS ON PRIOR LIGHT- AND...Effects of Single and Repetitive (Cumulative) Neodymium and Frequency-doubled Neodymium Laser Irradiations on Prior Light and Dark-Adapted Monkey Retinas

  12. All-photonic drying and sintering process via flash white light combined with deep-UV and near-infrared irradiation for highly conductive copper nano-ink

    OpenAIRE

    Hwang, Hyun-Jun; Oh, Kyung-Hwan; Kim, Hak-Sung

    2016-01-01

    We developed an ultra-high speed photonic sintering method involving flash white light (FWL) combined with near infrared (NIR) and deep UV light irradiation to produce highly conductive copper nano-ink film. Flash white light irradiation energy and the power of NIR/deep UV were optimized to obtain high conductivity Cu films. Several microscopic and spectroscopic characterization techniques such as scanning electron microscopy (SEM), a x-ray diffraction (XRD), and Fourier-transform infrared (F...

  13. Ethylene C-H Bond Activation by Neutral Mn2O5 Clusters under Visible Light Irradiation.

    Science.gov (United States)

    Yin, Shi; Bernstein, Elliot R

    2016-05-05

    A photo excitation fast flow reactor coupled with a single-photon ionization (118 nm, 10.5 eV) time-of-flight mass spectrometry (TOFMS) instrument is used to investigate reactions of neutral MnmOn clusters with C2H4 under visible (532 nm) light irradiation. Association products Mn2O5(C2H4) and Mn3O6,7(C2H4) are observed without irradiation. Under light irradiation, the Mn2O5(C2H4) TOFMS feature decreases, and a new species, Mn2O5H2, is observed. This light-activated reaction suggests that the visible radiation can induce the chemistry, Mn2O5 + C2H4 + hv(532 nm) → Mn2O5*(C2H4) → Mn2O5H2 + C2H2. High barriers (0.67 and 0.59 eV) are obtained on the ground-state potential energy surface (PES); the reaction is barrierless and thermodynamically favorable on the first excited-state PES, as performed by time-dependent density functional theory calculations. The calculational and experimental results suggest that Mn2O5-like structures on manganese oxide surfaces are the appropriate active catalytic sites for visible light photocatalysis of ethylene dehydrogenation.

  14. Red Light Combined with Blue Light Irradiation Regulates Proliferation and Apoptosis in Skin Keratinocytes in Combination with Low Concentrations of Curcumin.

    Science.gov (United States)

    Niu, Tianhui; Tian, Yan; Cai, Qing; Ren, Qu; Wei, Lizhao

    2015-01-01

    Curcumin is a widely known natural phytochemical from plant Curcuma longa. In recent years, curcumin has received increasing attention because of its capability to induce apoptosis and inhibit cell proliferation as well as its anti-inflammatory properties in different cancer cells. However, the therapeutic benefits of curcumin are severely hampered due to its particularly low absorption via trans-dermal or oral bioavailability. Phototherapy with visible light is gaining more and more support in dermatological therapy. Red light is part of the visible light spectrum, which is able to deeply penetrate the skin to about 6 mm, and directly affect the fibroblast of the skin dermis. Blue light is UV-free irradiation which is fit for treating chronic inflammation diseases. In this study, we show that curcumin at low concentrations (1.25-3.12 μM) has a strong anti-proliferative effect on TNF-α-induced psoriasis-like inflammation when applied in combination with light-emitting-diode devices. The treatment was especially effective when LED blue light at 405 nm was combined with red light at 630 or 660 nm, which markedly amplified the anti-proliferative and apoptosis-inducing effects of curcumin. The experimental results demonstrated that this treatment reduced the viability of human skin keratinocytes, decreased cell proliferation, induced apoptosis, inhibited NF-κB activity and activated caspase-8 and caspase-9 while preserving the cell membrane integrity. Moreover, the combined treatment also down-regulated the phosphorylation level of Akt and ERK. Taken together, our results indicated that the combination of curcumin with LED blue light united red light irradiation can attain a higher efficiency of regulating proliferation and apoptosis in skin keratinocytes.

  15. Red Light Combined with Blue Light Irradiation Regulates Proliferation and Apoptosis in Skin Keratinocytes in Combination with Low Concentrations of Curcumin.

    Directory of Open Access Journals (Sweden)

    Tianhui Niu

    Full Text Available Curcumin is a widely known natural phytochemical from plant Curcuma longa. In recent years, curcumin has received increasing attention because of its capability to induce apoptosis and inhibit cell proliferation as well as its anti-inflammatory properties in different cancer cells. However, the therapeutic benefits of curcumin are severely hampered due to its particularly low absorption via trans-dermal or oral bioavailability. Phototherapy with visible light is gaining more and more support in dermatological therapy. Red light is part of the visible light spectrum, which is able to deeply penetrate the skin to about 6 mm, and directly affect the fibroblast of the skin dermis. Blue light is UV-free irradiation which is fit for treating chronic inflammation diseases. In this study, we show that curcumin at low concentrations (1.25-3.12 μM has a strong anti-proliferative effect on TNF-α-induced psoriasis-like inflammation when applied in combination with light-emitting-diode devices. The treatment was especially effective when LED blue light at 405 nm was combined with red light at 630 or 660 nm, which markedly amplified the anti-proliferative and apoptosis-inducing effects of curcumin. The experimental results demonstrated that this treatment reduced the viability of human skin keratinocytes, decreased cell proliferation, induced apoptosis, inhibited NF-κB activity and activated caspase-8 and caspase-9 while preserving the cell membrane integrity. Moreover, the combined treatment also down-regulated the phosphorylation level of Akt and ERK. Taken together, our results indicated that the combination of curcumin with LED blue light united red light irradiation can attain a higher efficiency of regulating proliferation and apoptosis in skin keratinocytes.

  16. Red Light Combined with Blue Light Irradiation Regulates Proliferation and Apoptosis in Skin Keratinocytes in Combination with Low Concentrations of Curcumin

    Science.gov (United States)

    Cai, Qing; Ren, Qu; Wei, Lizhao

    2015-01-01

    Curcumin is a widely known natural phytochemical from plant Curcuma longa. In recent years, curcumin has received increasing attention because of its capability to induce apoptosis and inhibit cell proliferation as well as its anti-inflammatory properties in different cancer cells. However, the therapeutic benefits of curcumin are severely hampered due to its particularly low absorption via trans-dermal or oral bioavailability. Phototherapy with visible light is gaining more and more support in dermatological therapy. Red light is part of the visible light spectrum, which is able to deeply penetrate the skin to about 6 mm, and directly affect the fibroblast of the skin dermis. Blue light is UV-free irradiation which is fit for treating chronic inflammation diseases. In this study, we show that curcumin at low concentrations (1.25–3.12 μM) has a strong anti-proliferative effect on TNF-α-induced psoriasis-like inflammation when applied in combination with light-emitting-diode devices. The treatment was especially effective when LED blue light at 405 nm was combined with red light at 630 or 660 nm, which markedly amplified the anti-proliferative and apoptosis-inducing effects of curcumin. The experimental results demonstrated that this treatment reduced the viability of human skin keratinocytes, decreased cell proliferation, induced apoptosis, inhibited NF-κB activity and activated caspase-8 and caspase-9 while preserving the cell membrane integrity. Moreover, the combined treatment also down-regulated the phosphorylation level of Akt and ERK. Taken together, our results indicated that the combination of curcumin with LED blue light united red light irradiation can attain a higher efficiency of regulating proliferation and apoptosis in skin keratinocytes. PMID:26382065

  17. Performance of light sources and radiation sensors under low gravity realized by parabolic airplane flights

    Science.gov (United States)

    Hirai, Hiroaki; Kitaya, Yoshiaki; Hirai, Takehiro

    A fundamental study was conducted to establish an experimental system for space farming. Since to ensure optimal light for plant cultivation in space is of grave importance, this study examined the performance of light sources and radiation sensors under microgravity conditions created during the parabolic airplane flight. Three kinds of light sources, a halogen bulb, a fluorescent tube, and blue and red LEDs, and ten models of radiation sensors available in the market were used for the experiment. Surface temperature of the light sources, output signals from the radiation sensors, spectroscopic characteristics were measured at the gravity levels of 0.01, 1.0 and 1.8 G for 20 seconds each during parabolic airplane flights. As a result, the performance of the halogen lamp was affected the most by the gravity level among the three light sources. Under the microgravity conditions which do not raise heat convection, the temperature of the halogen lamp rose and the output of the radiation sensors increased. Spectral distributions of the halogen lamp indicated that peak wavelength appeared the highest at the level of 0.01G, which contributed to the increase in light intensity. In the case of red and blue LEDs, which are promising light sources in space farming, the temperature of both LED chips rose but irradiance from red LED increased and that from blue LED decreased under microgravity conditions due to the different thermal characteristics.

  18. Luminescence imaging of water during irradiation of X-ray photons lower energy than Cerenkov- light threshold

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi; Koyama, Shuji; Komori, Masataka [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center (Japan)

    2016-10-01

    Luminescence imaging of water using X-ray photon irradiation at energy lower than maximum energy of ~200 keV is thought to be impossible because the secondary electrons produced in this energy range do not emit Cerenkov- light. Contrary to this consensus assumption, we show that the luminescence imaging of water can be achieved by X-ray irradiation at energy lower than 120 keV. We placed water phantoms on a table with a conventional X-ray imaging system, and luminescence images of these phantoms were measured with a high-sensitivity, cooled charge coupled device (CCD) camera during X-ray photon irradiation at energy below 120 keV. We also carried out such imaging of an acrylic block and plastic scintillator. The luminescence images of water phantoms taken during X-ray photon irradiation clearly showed X-ray photon distribution. The intensity of the X-ray photon images of the phantom increased almost proportionally to the number of X-ray irradiations. Lower-energy X-ray photon irradiation showed lower-intensity luminescence at the deeper parts of the phantom due to the higher X-ray absorption in the water phantom. Furthermore, lower-intensity luminescence also appeared at the deeper parts of the acrylic phantom due to its higher density than water. The intensity of the luminescence for water was 0.005% of that for plastic scintillator. Luminescence imaging of water during X-ray photon irradiation at energy lower than 120 keV was possible. This luminescence imaging method is promising for dose estimation in X-ray imaging systems.

  19. Low Damage Reductive Patterning of Oxidized Alkyl Self-Assembled Monolayers through Vacuum Ultraviolet Light Irradiation in an Evacuated Environment.

    Science.gov (United States)

    Soliman, Ahmed I A; Tu, Yudi; Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki

    2017-10-17

    Through 172 nm vacuum ultraviolet light irradiation in a high vacuum condition (HV-VUV), well-defined micropatterns with a varied periodic friction were fabricated at the surface of self-assembled monolayers (SAMs) terminated with oxygenated groups. No apparent height contrast between the HV-VUV-irradiated and -masked areas was observed, which indicated the stability of the C-C skeleton of the assembled molecules. The trimming of oxygenated groups occurred through dissociating the C-O bonds and promoting the occurrence of α- and β-cleavages in the C═O-containing components. Hence, the HV-VUV treatment trimmed the oxygenated groups without degrading the C-C skeleton. The HV-VUV treatment influenced the order of the assembled molecules, and the step-terrace structure was distorted. The decrease in friction at the HV-VUV-irradiated domains was attributed to the dissociation of oxygenated groups. (3-Aminopropyl)trimethoxysilane (APTMS) aggregated at the masked areas of the HV-VUV-patterned SAM, where the oxygenated groups worked as anchors. APTMS aggregations did not exist at the irradiated areas, indicating the trimming of the oxygenated groups at these areas. The direct assembling of APTMS on the Si substrate at the irradiated areas was prevented by the remaining C-C skeleton.

  20. Ultraviolet light A irradiation induces immunosuppression associated with the generation of reactive oxygen species in human neutrophils

    Directory of Open Access Journals (Sweden)

    Cunbo Li

    2016-01-01

    Full Text Available Ultraviolet blood irradiation has been used as a physical therapy to treat many nonspecific diseases in clinics; however, the underlying mechanisms remain largely unclear. Neutrophils, the first line of host defense, play a crucial role in a variety of inflammatory responses. In the present work, we investigated the effects of ultraviolet light A (UVA on the immune functions of human neutrophils at the single-cell level by using an inverted fluorescence microscope. N-Formyl-methionyl-leucyl-phenylalanine (FMLP, a classic physiological chemotactic peptide, was used to induce a series of immune responses in neutrophils in vitro. FMLP-induced calcium mobilization, migration, and phagocytosis in human neutrophils was significantly blocked after treatment with 365nm UVA irradiation, demonstrating the immunosuppressive effects of UVA irradiation on neutrophils. Similar responses were also observed when the cells were pretreated with H2O2, a type of reactive oxygen species (ROS. Furthermore, UVA irradiation resulted in an increase in NAD(PH, a member of host oxidative stress in cells. Taken together, our data indicate that UVA irradiation results in immunosuppression associated with the production of ROS in human neutrophils.

  1. Effect of supplemental UV-A irradiation in solid-state lighting on the growth and phytochemical content of microgreens

    Science.gov (United States)

    Brazaitytė, A.; Viršilė, A.; Jankauskienė, J.; Sakalauskienė, S.; Samuolienė, G.; Sirtautas, R.; Novičkovas, A.; Dabašinskas, L.; Miliauskienė, J.; Vaštakaitė, V.; Bagdonavičienė, A.; Duchovskis, P.

    2015-01-01

    In this study, we sought to find and employ positive effects of UV-A irradiation on cultivation and quality of microgreens. Therefore, the goal of our study was to investigate the influence of 366, 390, and 402 nm UV-A LED wavelengths, supplemental for the basal solid-state lighting system at two UV-A irradiation levels on the growth and phytochemical contents of different microgreen plants. Depending on the species, supplemental UV-A irradiation can improve antioxidant properties of microgreens. In many cases, a significant increase in the investigated phytochemicals was found under 366 and 390 nm UV-A wavelengths at the photon flux density (12.4 μmol m-2 s-1). The most pronounced effect of supplemental UV-A irradiation was detected in pak choi microgreens. Almost all supplemental UV-A irradiation treatments resulted in increased leaf area and fresh weight, in higher 2,2-diphenyl-1-picrylhydrazyl free-radical scavenging activity, total phenols, anthocyanins, ascorbic acid, and α-tocopherol.

  2. Tropospheric Halogen Chemistry

    Science.gov (United States)

    von Glasow, R.; Crutzen, P. J.

    2003-12-01

    Halogens are very reactive chemicals that are known to play an important role in anthropogenic stratospheric ozone depletion chemistry, first recognized by Molina and Rowland (1974). However, they also affect the chemistry of the troposphere. They are of special interest because they are involved in many reaction cycles that can affect the oxidation power of the atmosphere indirectly by influencing the main oxidants O3 and its photolysis product OH and directly, e.g., by reactions of the Cl radical with hydrocarbons (e.g., CH4).Already by the middle of the nineteenth century, Marchand (1852) reported the presence of bromine and iodine in rain and other natural waters. He also mentions the benefits of iodine in drinking water through the prevention of goitres and cretinism. In a prophetic monograph "Air and Rain: The Beginnings of a Chemical Climatology," Smith (1872) describes measurements of chloride in rain water, which he states to originate partly from the oceans by a process that he compares with the bursting of "soap bubbles" which produces "small vehicles" that transfer small spray droplets of seawater to the air. From deviations of the sulfate-to-chloride ratio in coastal rain compared to seawater, Smith concluded that chemical processes occur once the particles are airborne.For almost a century thereafter, however, atmospheric halogens received little attention. One exception was the work by Cauer (1939), who reported that iodine pollution has been significant in Western and Central Europe due to the inefficient burning of seaweed, causing mean gas phase atmospheric concentrations as high as or greater than 0.5 μg m-3. In his classical textbook Air Chemistry and Radioactivity, Junge (1963) devoted less than three pages to halogen gas phase chemistry, discussing chlorine and iodine. As reviewed by Eriksson (1959a, b), the main atmospheric source of halogens is sea salt, derived from the bursting of bubbles of air which are produced by ocean waves and other

  3. Photoreduction preparation of Cu2O@polydopamine nanospheres with enhanced photocatalytic activity under visible light irradiation

    Science.gov (United States)

    Zhou, Xiaosong; Jin, Bei; Luo, Jin; Gu, Xingxing; Zhang, Shanqing

    2017-10-01

    Cuprous oxide (Cu2O) suffers from severe electron-hole pairs recombination, instability and low photocatalytic degradation efficiency, though it has been considered as an excellent visible light photocatalyst. The incorporation of the Cu2O with other photocatalysts can address these problems. Herein, unique Cu2O@ polydopamine (PDA) nanospheres are prepared by a simple photo-reduction approach. Due to the synergistic effects of the Cu2O and PDA semiconductors, the Cu2O@PDA nanospheres composite possesses enhanced photocatalytic activity and extended life time for the degradation of the methyl orange under visible light irradiation.

  4. [Inactivation mechanism of microorganisms by the synergy of silver and light irradiation, and the application in household electrical appliances].

    Science.gov (United States)

    He, Jinshan; Moriya, Yoshifumi; Oketa, Takemi; Sasabe, Shigeru; Nishida, Hirofumi; Chen, Lesheng; Zhu, Shenmin; Zhang, Di; Omori, Hideki; Cao, Guangyi

    2008-06-01

    The inactivation efficiencies of microorganisms were found to be enhanced by using silver solution together with ultraviolet light (UV-A, 395 nm) irradiation. The inactivation efficiencies were improved remarkably especially in eukaryotic microorganism. To make clear the inactivation mechanism of microorganisms by the combination effect of silver and ultraviolet light irradiation, the resultant solution was characterized by ESR (Electron spin resonance, ESR). Scanning electron microscopy (SEM) and the methnd for measuring enzyme activity of mitochondria for eukarvotic cells were used to conjecture the mechanism, by analysis of the morphological and physiologic changes in eukaryotic cells. It is proposed that silver oxide (Ag20) can be activated by ultraviolet light irradiation and react with water molecules to produce hydroxyl radical (.OH). Hydroxyl radical could damage cell wall of eukaryotic microorganisms, and inactivate the enzyme activity of mitochondria of eukaryotic microorganism cells. Accordingly, eukaryotic microorganism cells would die. In the experiment, Staphylococcus aureus was employed as the representative of prokaryotic microorganisms, and Candida albicans and Trichophyton mentagrophytes as the representative of eukaryotic microorganisms, respectively. Moreover, the results of the technology applied to washing machine were presented and discussed.

  5. Reduction of Cr(VI) to Cr(III) using silicon nanowire arrays under visible light irradiation.

    Science.gov (United States)

    Fellahi, Ouarda; Barras, Alexandre; Pan, Guo-Hui; Coffinier, Yannick; Hadjersi, Toufik; Maamache, Mustapha; Szunerits, Sabine; Boukherroub, Rabah

    2016-03-05

    We report an efficient visible light-induced reduction of hexavalent chromium Cr(VI) to trivalent Cr(III) by direct illumination of an aqueous solution of potassium dichromate (K2Cr2O7) in the presence of hydrogenated silicon nanowires (H-SiNWs) or silicon nanowires decorated with copper nanoparticles (Cu NPs-SiNWs) as photocatalyst. The SiNW arrays investigated in this study were prepared by chemical etching of crystalline silicon in HF/AgNO3 aqueous solution. The Cu NPs were deposited on SiNW arrays via electroless deposition technique. Visible light irradiation of an aqueous solution of K2Cr2O7 (10(-4)M) in presence of H-SiNWs showed that these substrates were not efficient for Cr(VI) reduction. The reduction efficiency achieved was less than 10% after 120 min irradiation at λ>420 nm. Addition of organic acids such as citric or adipic acid in the solution accelerated Cr(VI) reduction in a concentration-dependent manner. Interestingly, Cu NPs-SiNWs was found to be a very efficient interface for the reduction of Cr(VI) to Cr(III) in absence of organic acids. Almost a full reduction of Cr(VI) was achieved by direct visible light irradiation for 140 min using this photocatalyst. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Enhanced photocatalytic performance of BiVO4 in aqueous AgNO3 solution under visible light irradiation

    Science.gov (United States)

    Huang, Chien-Kai; Wu, Tsunghsueh; Huang, Chang-Wei; Lai, Chi-Yung; Wu, Mei-Yao; Lin, Yang-Wei

    2017-03-01

    Monoclinic-phase bismuth vanadate (BiVO4) with a 2.468 eV band gap exhibited enhanced synergic photodegradation activity toward methylene blue (MB) when combined with silver ions (Ag+) in an aqueous solution under visible light irradiation. The mass ratio of AgNO3 to BiVO4 and the calcination temperature were discovered to considerably affect the degradation activity of BiVO4/Ag+. Superior photocatalytic performance was obtained when BiVO4 was mixed with 0.01%(w/v) AgNO3 solution, and complete degradation of MB was achieved after 25 min visible light irradiation, outperforming BiVO4 or AgNO3 solution alone. The enhanced photodegradation was investigated using systematic luminescence measurements, electrochemical impedance spectroscopy, and scavenger addition, after which a photocatalytic mechanism for MB degradation under visible light irradiation was identified that involved oxygen radicals and holes. This study also discovered the two dominating processes involved in enhancing the electron-hole separation efficiency and reducing their recombination rate, namely photoreduction of Ag+ and the formation of a BiVO4/Ag heterojunction. The synergic effect between BiVO4 and Ag+ was discovered to be unique. BiVO4/Ag+ was successfully used to degrade two other dyes and disinfect Escherichia Coli. A unique fluorescent technique using BiVO4 and a R6G solution to detect Ag+ ions in water was discovered.

  7. Enhanced photocatalytic ozonation of organics by g-C₃N ₄ under visible light irradiation.

    Science.gov (United States)

    Liao, Gaozu; Zhu, Dongyun; Li, Laisheng; Lan, Bingyan

    2014-09-15

    Graphitic carbon nitride (g-C3N4) was employed as the active photocatalyst in the photocatalytic ozonation coupling system in the present study. g-C3N4 was prepared by directly heating thiourea in air at 550°C. XRD, FT-IR, UV-vis was used to characterize the structure and optical property. Oxalic acid and bisphenol A were selected as model substances for photocatalytic ozonation reactions to evaluate the catalytic ability of g-C3N4 (g-C3N4/Vis/O3). The results showed that the degradation ratio of oxalic acid with g-C3N4/Vis/O3 was 65.2% higher than the sum of ratio when it was individually decomposed by g-C3N4/Vis and O3. The TOC removal of biphenol A with g-C3N4/Vis/O3 was 2.17 times as great as the sum of the ratio when using g-C3N4/Vis and O3. This improvement was attributed to the enhanced synergistic effect between photocatalysis and ozonation by g-C3N4. Under visible light irradiation, the photo-generated electrons produced on g-C3N4 facilitated the electrons transfer owing to the more negative conduction band potential (-1.3V versus NHE). It meant that the photo-generated electrons could be trapped by ozone and reaction with it more easily. Subsequently, the yield of hydroxyl radicals was improved so as to enhance the organics degradation efficiency. This work indicated that metal-free g-C3N4 could be an excellent catalyst for mineralization of organic compounds in waste control. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Self-Strengthening Hybrid Dental Adhesive via Visible-light Irradiation Triple Polymerization.

    Science.gov (United States)

    Song, Linyong; Ye, Qiang; Ge, Xueping; Misra, Anil; Tamerler, Candan; Spencer, Paulette

    2016-01-01

    A self-strengthening methacrylate-based dental adhesive system was developed by introducing an epoxy cyclohexyl trimethoxysilane (TS) which contains both epoxy and methoxysilyl functional groups. The experimental formulation, HEMA/BisGMA/TS (22.5/27.5/50, wt%), was polymerized by visible-light. Real-time Fourier transform infrared spectroscopy (FTIR) was used to investigate in situ the free radical polymerization of methacrylate, ring-opening cationic polymerization of epoxy, and photoacid-induced sol-gel reactions. Among the three simultaneous reactions, the reaction rate of the free radical polymerization was the highest and the hydrolysis/condensation rate was the lowest. With 40s-irradiation, the degrees of conversion of the double bond and epoxy groups at 600 s were 73.2±1.2%, 87.9±2.4%, respectively. Hydrolysis of the methoxysilyl group was initially induced reaction were effective in catalyzing both epoxy ring-opening polymerization and methoxysilyl sol-gel reaction. The mechanical properties of copolymers made with TS concentrations from 5 to 35 wt% were obtained using dynamic mechanical analysis (DMA). In wet conditions, the storage moduli at 70 °C and glass transition temperature were significantly higher than that of the control (p<0.05); these properties increased with TS concentration and storage time. The post reaction of hydrolysis/condensation of alkoxysilane could provide persistent strengthening whether in a neutral or acidic environment and these characteristics could lead to enhanced mechanical properties in the oral environment. The cumulative amount of leached species decreased significantly in the TS-containing copolymers. These results provide valuable information for the development of dental adhesives with reduced leaching of methacrylate monomers and enhanced mechanical properties under the wet, oral environment.

  9. Decomposition of perfluorooctanoic acid by ultraviolet light irradiation with Pb-modified titanium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Meng-Jia [Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, Taiwan, ROC (China); Lo, Shang-Lien, E-mail: sllo@ntu.edu.tw [Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, Taiwan, ROC (China); Lee, Yu-Chi [Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, Taiwan, ROC (China); Kuo, Jeff [Department of Civil and Environmental Engineering, California State University, Fullerton, CA 92834 (United States); Wu, Chung-Hsin [Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, 415 Chien Kung Road, Kaohsiung, Taiwan, ROC (China)

    2016-02-13

    Highlights: • Photocatalytic decomposition of PFOA was studied. • UV/Pb–TiO{sub 2} system show much better activity than UV/ TiO{sub 2} system. • Photocatalytic half-life of PFOA was shortened to 1.3 h. • Lower pHs result in an increase in removal efficiency of PFOA. • The by-products of the PFOA decomposition reactions are detailed. - Abstract: Perfluorooctanoic acid (PFOA, C{sub 7}H{sub 15}COOH) is widely used in industrial and commercial applications. It has become a global concern due to its widespread occurrence in water bodies and adverse environmental impact. PFOA could not be effectively removed by the conventional UV/TiO{sub 2} system. This study synthesized Pb-modified TiO{sub 2} catalyst and used it as a catalyst with light irradiation for PFOA decomposition. It was found that the Pb–TiO{sub 2} catalyst could produce traps to capture photo-induced electrons or holes that lead to better photocatalytic efficiencies. Rate constant values for PFOA decomposition by the UV/TiO{sub 2} and UV/Pb–TiO{sub 2} systems were determined to be 0.0158 and 0.5136 h{sup −1}, respectively. The PFOA decomposition in the UV/Pb–TiO{sub 2} system is 32.5 times faster than that in the UV/TiO{sub 2} system. The UV/Pb–TiO{sub 2} system yielded a better performance than those of the UV/Fe-TiO{sub 2} and UV/Cu-TiO{sub 2} systems. During the reaction, PFOA decomposed stepwisely into shorter-chain perfluorocarboxylic acids and F{sup −}.

  10. In vitro assessment of pulp chamber temperature of different teeth submitted to dental bleaching associated with LED/laser and halogen lamp appliances.

    Science.gov (United States)

    Torres, Carlos Rocha Gomes; Caneppele, Taciana Marco Ferraz; Arcas, Felipe Carlos Dias; Borges, Alessandra Buhler

    2008-01-01

    This study sought to assess the pulp chamber temperature in different groups of human teeth that had been bleached using hydrogen peroxide gel activated with halogen lamps or hybrid LED/laser appliances. Four groups of ten teeth (maxillary central incisors, mandibular incisors, mandibular canines, and maxillary canines) were used. A digital thermometer with a K-type thermocouple was placed inside pulp chambers that had been filled with thermal paste. A 35% hydrogen peroxide-based red bleaching gel was applied to all teeth and photocured for a total of three minutes and 20 seconds (five activations of 40 seconds each), using light from an LED/laser device and a halogen lamp. The temperatures were gauged every 40 seconds and the data were analyzed by three-way ANOVA, followed by Tukey's test. Regardless of the light source, statistically significant differences were observed between the groups of teeth. The mean temperature values (+/- SD) were highest for maxillary central incisors and lowest for mandibular canines. The halogen lamp appliance produced more pulp chamber heating than the LED/laser appliance. The increase in irradiation time led to a significant increase in temperature.

  11. Microdureza de resinas em função da cor e luz halógena Microhardness of resins as a function of color and halogen light

    Directory of Open Access Journals (Sweden)

    Fábio Martins

    2002-09-01

    Full Text Available O objetivo desse trabalho foi avaliar a influência da intensidade da luz e cor de uma resina composta no grau de dureza Knoop. Corpos-de-prova foram confeccionados utilizando-se matrizes de poliéster envoltas por um anel de cobre, contendo uma cavidade padronizada de 6 mm de diâmetro por 2 mm de espessura. Estas cavidades foram preenchidas com resina composta selecionada, Fill Magic - Vigodent, com as cores A3, B3, C3, D3 e I, fotopolimerizadas através de um fotopolimerizador Elipar, calibrado para produzir 3 intensidades de luz diferentes: 450 mW/cm², 800 mW/cm² e uma intensidade de luz crescente de 100 a 800 mW/cm². Foram confeccionados 90 corpos-de-prova em que o tempo de exposição da resina à luz halógena foi de 40 s. As amostras foram armazenadas em tubos de ensaio com água destilada a 37 ± 1ºC. Após este período, foram realizados os testes de dureza Knoop na região de superfície e fundo. Os resultados mostraram que houve diferença estatística em relação a intensidade de luz, entretanto em relação a cor, não houve diferença estatística. Os autores concluíram que a cor do compósito não influencia a dureza Knoop e que a intensidade progressiva promoveu os melhores resultados de dureza Knoop.The aim of this study was to evaluate the influence of light intensity and the influence of the color of a composite resin on Knoop hardness. Samples were confected utilizing polyester matrices with 6 mm of diameter and 2 mm of depth. The matrices were filled with composite resin (Fill Magic - Vigodent, colors A3, B3, C3, D3 and I, and light-cured by means of an Elipar light-curing unit in three different light intensities: 450 mW/cm2, 800 mW/cm² and an increasing intensity setup of 100 mW/cm² to 800 mW/cm². Ninety test specimens were confected, with the standard curing time of 40 seconds. The specimens were stored at 37 ± 1ºC and immersed in distillate water. The Knoop test was carried out in superficial and deep areas

  12. Performance of Ag-TiO2 Photocatalysts towards the Photocatalytic Disinfection of Water under Interior-Lighting and Solar-Simulated Light Irradiations

    Directory of Open Access Journals (Sweden)

    Camilo A. Castro

    2012-01-01

    Full Text Available This paper reports the characterization and photoactivity of Ag-TiO2 materials using different amounts of silver during the hydrothermal synthesis. Photocatalysts were characterized by means of TEM, XPS, XRD, DRS, and N2 sorption isotherms to determine the textural properties. The photocatalyst's configuration was observed to be as anatase-brookite mixed phase particles with Ag partially oxidized aggregates on the TiO2 surface, which increased visible light absorption of the material. Moreover, photoproduction of singlet oxygen was followed by EPR analysis under visible light irradiations following the formation of TEMPOL. Such photoproduction was totally decreased by using the singlet oxygen scavenger DABCO. Photocatalysts were tested towards the photocatalytic disinfection of water suing a solar light simulator and an interior-light irradiation setup. Results evidenced an increase in the photooxidative effect of TiO2, while dark processes evidenced that part of the inactivation process is due to the Ag-TiO2 surface bactericidal effect and possible lixiviated Ag+.

  13. Antimicrobial photodynamic activity and cytocompatibility of Au25(Capt)18clusters photoexcited by blue LED light irradiation.

    Science.gov (United States)

    Miyata, Saori; Miyaji, Hirofumi; Kawasaki, Hideya; Yamamoto, Masaki; Nishida, Erika; Takita, Hiroko; Akasaka, Tsukasa; Ushijima, Natsumi; Iwanaga, Toshihiko; Sugaya, Tsutomu

    2017-01-01

    Antimicrobial photodynamic therapy (aPDT) has beneficial effects in dental treatment. We applied captopril-protected gold (Au 25 (Capt) 18 ) clusters as a novel photosensitizer for aPDT. Photoexcited Au clusters under light irradiation generated singlet oxygen ( 1 O 2 ). Accordingly, the antimicrobial and cytotoxic effects of Au 25 (Capt) 18 clusters under dental blue light-emitting diode (LED) irradiation were evaluated. 1 O 2 generation of Au 25 (Capt) 18 clusters under blue LED irradiation (420-460 nm) was detected by a methotrexate (MTX) probe. The antimicrobial effects of photoexcited Au clusters (0, 5, 50, and 500 μg/mL) on oral bacterial cells, such as Streptococcus mutans, Aggregatibacter actinomycetemcomitans , and Porphyromonas gingivalis , were assessed by morphological observations and bacterial growth experiments. Cytotoxicity testing of Au clusters and blue LED irradiation was then performed against NIH3T3 and MC3T3-E1 cells. In addition, the biological performance of Au clusters (500 μg/mL) was compared to an organic dye photosensitizer, methylene blue (MB; 10 and 100 μg/mL). We confirmed the 1 O 2 generation ability of Au 25 (Capt) 18 clusters through the fluorescence spectra of oxidized MTX. Successful application of photoexcited Au clusters to aPDT was demonstrated by dose-dependent decreases in the turbidity of oral bacterial cells. Morphological observation revealed that application of Au clusters stimulated destruction of bacterial cell walls and inhibited biofilm formation. Aggregation of Au clusters around bacterial cells was fluorescently observed. However, photoexcited Au clusters did not negatively affect the adhesion, spreading, and proliferation of mammalian cells, particularly at lower doses. In addition, application of Au clusters demonstrated significantly better cytocompatibility compared to MB. We found that a combination of Au 25 (Capt) 18 clusters and blue LED irradiation exhibited good antimicrobial effects through 1 O 2

  14. Antimicrobial photodynamic activity and cytocompatibility of Au25(Capt)18 clusters photoexcited by blue LED light irradiation

    Science.gov (United States)

    Miyata, Saori; Miyaji, Hirofumi; Kawasaki, Hideya; Yamamoto, Masaki; Nishida, Erika; Takita, Hiroko; Akasaka, Tsukasa; Ushijima, Natsumi; Iwanaga, Toshihiko; Sugaya, Tsutomu

    2017-01-01

    Antimicrobial photodynamic therapy (aPDT) has beneficial effects in dental treatment. We applied captopril-protected gold (Au25(Capt)18) clusters as a novel photosensitizer for aPDT. Photoexcited Au clusters under light irradiation generated singlet oxygen (1O2). Accordingly, the antimicrobial and cytotoxic effects of Au25(Capt)18 clusters under dental blue light-emitting diode (LED) irradiation were evaluated. 1O2 generation of Au25(Capt)18 clusters under blue LED irradiation (420–460 nm) was detected by a methotrexate (MTX) probe. The antimicrobial effects of photoexcited Au clusters (0, 5, 50, and 500 μg/mL) on oral bacterial cells, such as Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis, were assessed by morphological observations and bacterial growth experiments. Cytotoxicity testing of Au clusters and blue LED irradiation was then performed against NIH3T3 and MC3T3-E1 cells. In addition, the biological performance of Au clusters (500 μg/mL) was compared to an organic dye photosensitizer, methylene blue (MB; 10 and 100 μg/mL). We confirmed the 1O2 generation ability of Au25(Capt)18 clusters through the fluorescence spectra of oxidized MTX. Successful application of photoexcited Au clusters to aPDT was demonstrated by dose-dependent decreases in the turbidity of oral bacterial cells. Morphological observation revealed that application of Au clusters stimulated destruction of bacterial cell walls and inhibited biofilm formation. Aggregation of Au clusters around bacterial cells was fluorescently observed. However, photoexcited Au clusters did not negatively affect the adhesion, spreading, and proliferation of mammalian cells, particularly at lower doses. In addition, application of Au clusters demonstrated significantly better cytocompatibility compared to MB. We found that a combination of Au25(Capt)18 clusters and blue LED irradiation exhibited good antimicrobial effects through 1O2 generation and biosafe

  15. Construction of Tungsten Halogen, Pulsed LED, and Combined Tungsten Halogen-LED Solar Simulators for Solar Cell I-V Characterization and Electrical Parameters Determination

    Directory of Open Access Journals (Sweden)

    Anon Namin

    2012-01-01

    Full Text Available I-V characterization of solar cells is generally done under natural sunlight or solar simulators operating in either a continuous mode or a pulse mode. Simulators are classified on three features of irradiance, namely, spectral match with respect to air mass 1.5, spatial uniformity, and temporal stability. Commercial solar simulators use Xenon lamps and halogen lamps, whereas LED-based solar simulators are being developed. In this work, we build and test seven simulators for solar cell characterization, namely, one tungsten halogen simulator, four monochromatic (red, green, blue, and white LED simulators, one multicolor LED simulator, and one tungsten halogen-blue LED simulator. The seven simulators provide testing at nonstandard test condition. High irradiance from simulators is obtained by employing elevated supply voltage to tungsten halogen lamps and high pulsing voltages to LEDs. This new approach leads to higher irradiance not previously obtained from tungsten halogen lamps and LEDs. From I-V curves, electrical parameters of solar cell are made and corrected based on methods recommended in the IEC 60891 Standards. Corrected values obtained from non-STC measurements are in good agreement with those obtained from Class AAA solar simulator.

  16. SU-F-J-56: The Connection Between Cherenkov Light Emission and Radiation Absorbed Dose in Proton Irradiated Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Darafsheh, A; Kassaee, A; Finlay, J [University of Pennsylvania, Philadelphia, PA (United States); Taleei, R [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: Range verification in proton therapy is of great importance. Cherenkov light follows the photon and electron energy deposition in water phantom. The purpose of this study is to investigate the connection between Cherenkov light generation and radiation absorbed dose in a water phantom irradiated with proton beams. Methods: Monte Carlo simulation was performed by employing FLUKA Monte Carlo code to stochastically simulate radiation transport, ionizing radiation dose deposition, and Cherenkov radiation in water phantoms. The simulations were performed for proton beams with energies in the range 50–600 MeV to cover a wide range of proton energies. Results: The mechanism of Cherenkov light production depends on the initial energy of protons. For proton energy with 50–400 MeV energy that is below the threshold (∼483 MeV in water) for Cherenkov light production directly from incident protons, Cherenkov light is produced mainly from the secondary electrons liberated as a result of columbic interactions with the incident protons. For proton beams with energy above 500 MeV, in the initial depth that incident protons have higher energy than the Cherenkov light production threshold, the light has higher intensity. As the slowing down process results in lower energy protons in larger depths in the water phantom, there is a knee point in the Cherenkov light curve vs. depth due to switching the Cherenkov light production mechanism from primary protons to secondary electrons. At the end of the depth dose curve the Cherenkov light intensity does not follow the dose peak because of the lack of high energy protons to produce Cherenkov light either directly or through secondary electrons. Conclusion: In contrast to photon and electron beams, Cherenkov light generation induced by proton beams does not follow the proton energy deposition specially close to the end of the proton range near the Bragg peak.

  17. Comparative fitness of irradiated light brown apple moths (Lepidoptera: Tortricidae) in a wind tunnel, hedgerow, and vineyard.

    Science.gov (United States)

    Suckling, David M; Stringer, Lloyd D; Mitchell, Vanessa J; Sullivan, Thomas E S; Sullivan, Nicola J; Simmons, Gregory S; Barrington, Anne M; El-Sayed, Ashraf M

    2011-08-01

    Light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), is the target of the sterile insect technique, but reduced moth fitness from irradiation lowers the effective overflooding ratio of sterile to wild moths. New measures of insect quality are being sought to improve field performance of irradiated insects, thus improving the cost effectiveness of this technique. Male pupae were irradiated at intervals between 0 and 300 Gy, and adult flight success was assessed in a wind tunnel equipped with flight track recording software. A dose response was evident with reduced successful search behaviors at higher irradiation doses. Irradiation at 250 Gy reduced arrival success to 49% of untreated controls, during 2-min assays. Mark-release-recapture of males irradiated at 250 Gy indicated reduced male moth recapture in hedgerows (75% of control values of 7.22% +/- 1.20 [SEM] males recaptured) and in vineyards (78% of control values 10.5% +/- 1.66% [SEM] recaptured). Males dispersed similar distances in both habitats, and overflooding ratios dropped off rapidly from the release point in both landscapes. Transects of traps with central releases proved to be an efficient method for measuring the quality of released males. Relative field performance of moths was greater than suggested by wind tunnel performance, which could be due to time differences between the two assays, two-minute wind tunnel tests compared with days in the field treatments. Release strategies involving ground releases should consider the effect of limited postrelease dispersal. Aerial release could solve this problem and warrants investigation.

  18. Ultraviolet light-emitting diode irradiation-induced cell death in HL-60 human leukemia cells in vitro

    Science.gov (United States)

    XIE, DONG; SUN, YAN; WANG, LINGZHEN; LI, XIAOLING; ZANG, CHUANNONG; ZHI, YUNLAI; SUN, LIRONG

    2016-01-01

    Ultraviolet (UV) radiation is considered to be a potent cell-damaging agent in various cell lineages; however, the effect of UV light-emitting diode (LED) irradiation on human cells remains unclear. The aim of the present study was to examine the effect of UV LED irradiation emitting at 280 nm on cultured HL-60 human leukemia cells, and to explore the underlying mechanisms. HL-60 cells were irradiated with UV LED (8, 15, 30 and 60 J/m2) and incubated for 2 h after irradiation. The rates of cell proliferation and apoptosis, the cell cycle profiles and the mRNA expression of B-cell lymphoma 2 (Bcl-2) were detected using cell counting kit-8, multicaspase assays, propidium iodide staining and reverse transcription-quantitative polymerase chain reaction, respectively. The results showed that UV LED irradiation (8–60 J/m2) inhibited the proliferation of HL-60 cells in a dose-dependent manner. UV LED at 8–30 J/m2 induced dose-dependent apoptosis and G0/G1 cell cycle arrest, and inhibited the expression of Bcl-2 mRNA, while UV LED at 60 J/m2 induced necrosis. In conclusion, 280 nm UV LED irradiation inhibits proliferation and induces apoptosis and necrosis in cultured HL-60 cells. In addition, the cell cycle arrest at the G0/G1 phase and the downregulation of Bcl-2 mRNA expression were shown to be involved in UV LED-induced apoptosis. PMID:26820261

  19. Light curing in orthodontics; should we be concerned?

    Science.gov (United States)

    McCusker, Neil; Lee, Siu Man; Robinson, Stephen; Patel, Naresh; Sandy, Jonathan R; Ireland, Anthony J

    2013-06-01

    Light cured materials are increasingly used in orthodontic clinical practice and concurrent with developments in materials have been developments in light curing unit technology. In recent years the irradiances of these units have increased. The aim of this study was to determine the safe exposure times to both direct and reflected light. The weighted irradiance and safe exposure times of 11 dental curing lights (1 plasma arc, 2 halogen and 8 LED lights) were determined at 6 distances (2-60 cm) from the light guide tip using a spectroradiometer. In addition, using the single most powerful light, the same two parameters were determined for reflected light. This was done at a distance of 10 cm from the reflected light, but during simulated bonding of 8 different orthodontic brackets of three material types, namely stainless steel, ceramic and composite. The results indicate that the LED Fusion lamp had the highest weighted irradiance and the shortest safe exposure time. With this light the maximum safe exposure time without additional eye protection for the patient (at 10 cm), the operator (at 30 cm) and the assistant (at 60 cm) ranged from 2.5 min, 22.1 min and 88.8 min respectively. This indicates a relatively low short term risk during normal operation of dental curing lights. For reflected light at a distance of 10 cm the risk was even lower, but was affected by the material and shape of the orthodontic bracket under test. The short term risks associated with the use of dental curing lights, halogen, LED or plasma, appear to be low, particularly if as is the case adequate safety precautions are employed. The same is true for reflected light from orthodontic brackets during bonding. What is still unclear is the potential long term ocular effects of prolonged exposure to the blue light generated from dental curing lights. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  20. In vitro pulp chamber temperature rise from irradiation and exotherm of flowable composites.

    Science.gov (United States)

    Baroudi, Kusai; Silikas, Nick; Watts, David C

    2009-01-01

    The aim of this study was to investigate the pulpal temperature rise induced during the polymerization of flowable and non-flowable composites using light-emitting diode (LED) and halogen (quartz-tungsten-halogen) light-curing units (LCUs). Five flowable and three non-flowable composites were examined. Pulpal temperature changes were recorded over 10 min in a sample primary tooth by a thermocouple. A conventional quartz-tungsten-halogen source and two LEDs, one of which was programmable, were used for light curing the resin composites. Three repetitions per material were made for each LCU. There was a wide range of temperature rises among the materials (P Temperature rises ranged between 1.3 degrees C for Filtek Supreme irradiated by low-power LED and 4.5 degrees C for Grandio Flow irradiated by high-power LED. The highest temperature rises were observed with both the LED high-power and soft-start LCUs. The time to reach the exothermic peak varied significantly between the materials (P temperature rise is related to both the radiant energy output from LCUs and the polymerization exotherm of resin composites. A greater potential risk for heat-induced pulp damage might be associated with high-power LED sources. Flowable composites exhibited higher temperature rises than non-flowable materials, because of higher resin contents.

  1. The Halogen Occultation Experiment

    Science.gov (United States)

    Russell, James M., III; Gordley, Larry L.; Park, Jae H.; Drayson, S. R.; Hesketh, W. D.; Cicerone, Ralph J.; Tuck, Adrian F.; Frederick, John E.; Harries, John E.; Crutzen, Paul J.

    1993-01-01

    The Halogen Occultation Experiment (HALOE) uses solar occultation to measure vertical profiles of O3, HCl, HF, CH4, H2O, NO, NO2, aerosol extinction, and temperature versus pressure with an instantaneous vertical field of view of 1.6 km at the earth limb. Latitudinal coverage is from 80 deg S to 80 deg N over the course of 1 year and includes extensive observations of the Antarctic region during spring. The altitude range of the measurements extends from about 15 km to about 60-130 km, depending on channel. Experiment operations have been essentially flawless, and all performance criteria either meet or exceed specifications. Internal data consistency checks, comparisons with correlative measurements, and qualitative comparisons with 1985 atmospheric trace molecule spectroscopy (ATMOS) results are in good agreement. Examples of pressure versus latitude cross sections and a global orthographic projection for the September 21 to October 15, 1992, period show the utility of CH4, HF, and H2O as tracers, the occurrence of dehydration in the Antarctic lower stratosphere, the presence of the water vapor hygropause in the tropics, evidence of Antarctic air in the tropics, the influence of Hadley tropical upwelling, and the first global distribution of HCl, HF, and NO throughout the stratosphere. Nitric oxide measurements extend through the lower thermosphere.

  2. Optical properties and light irradiance of monolithic zirconia at variable thicknesses.

    Science.gov (United States)

    Sulaiman, Taiseer A; Abdulmajeed, Aous A; Donovan, Terrence E; Ritter, André V; Vallittu, Pekka K; Närhi, Timo O; Lassila, Lippo V

    2015-10-01

    The aims of this study were to: (1) estimate the effect of polishing on the surface gloss of monolithic zirconia, (2) measure and compare the translucency of monolithic zirconia at variable thicknesses, and (3) determine the effect of zirconia thickness on irradiance and total irradiant energy. Four monolithic partially stabilized zirconia (PSZ) brands; Prettau® (PRT, Zirkonzahn), Bruxzir® (BRX, Glidewell), Zenostar® (ZEN, Wieland), Katana® (KAT, Noritake), and one fully stabilized zirconia (FSZ); Prettau Anterior® (PRTA, Zirkonzahn) were used to fabricate specimens (n=5/subgroup) with different thicknesses (0.5, 0.7, 1.0, 1.2, 1.5, and 2.0mm). Zirconia core material ICE® Zircon (ICE, Zirkonzahn) was used as a control. Surface gloss and translucency were evaluated using a reflection spectrophotometer. Irradiance and total irradiant energy transmitted through each specimen was quantified using MARC® Resin Calibrator. All specimens were then subjected to a standardized polishing method and the surface gloss, translucency, irradiance, and total irradiant energy measurements were repeated. Statistical analysis was performed using two-way ANOVA and post-hoc Tukey's tests (pzirconia and the amount was brand dependent (pzirconia can affect the ultimate clinical outcome of the optical properties of zirconia restorations. FSZ is relatively more polishable and translucent than PSZ. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  3. A novel three-stage light irradiation strategy in the submerged fermentation of medicinal mushroom Ganoderma lucidum for the efficient production of ganoderic acid and Ganoderma polysaccharides.

    Science.gov (United States)

    Zhang, Wei; Tang, Ya-Jie

    2008-01-01

    A novel three-stage light irradiation strategy in the submerged fermentation of medicinal mushroom Ganoderma lucidum for the efficient production of bioactive metabolites ganoderic acid (GA) and Ganoderma polysaccharides was developed. Significance of light quality, i.e., blue light (390-500 nm, lambda(max) = 470 nm), red light (560-700 nm, lambda(max) = 625 nm), and white light (400-740 nm, lambda(max) = 550 nm), was studied at first. Interestingly, there was a gradual decrease trend of GA content after the culture of day 2 when the maximal GA content was obtained, while GA content decreased slowly under white light irradiation after day 6. The dark environment was favorable to the specific GA biosynthesis (i.e., GA content) before day 6, and after that the optimum was white light irradiation. A relatively lower irradiation density of white light (i.e., 0.94 and 2.82 W/m(2)) was beneficial for the specific GA biosynthesis before day 6, while GA content was higher under higher irradiation density of white light (i.e., 4.70 and 9.40 W/m(2)) at the later-stage of cultivation. 4.70 W/m(2) white light irradiation culture was the best from the viewpoint of GA accumulation. Therefore, a two-stage light irradiation strategy by combing the first 2 days dark culture with the following 4.70 W/m(2) white light irradiation culture was developed. The highest GA production in the two-stage culture was 276.0 +/- 12.5 mg/L, which was increased by 19% compared to 4.70 W/m(2) white light irradiation culture (i.e., 232.4 +/- 15.8 mg/L) and by 178% compared to the dark culture (i.e., 99.4 +/- 1.0 mg/L). Although there still existed a gradual decrease trend of GA content after day 2 when the maximal GA content was obtained in the two-stage culture. Following three-stage light irradiation strategy was further demonstrated in order to turn around the sharp decrease of GA content after day 2. The first-stage was the 2-day dark culture; the second-stage was the following six-day 0.94 W/m(2

  4. Reduction of Cr(VI) to Cr(III) using silicon nanowire arrays under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Fellahi, Ouarda [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); Centre de Recherche en Technologie des Semi-conducteurs pour l' Energétique-CRTSE 02, Bd Frantz Fanon, BP. 140, Alger 7 Merveilles (Algeria); Barras, Alexandre [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); Pan, Guo-Hui [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Dong Nanhu Road, Changchun 130033 (China); Coffinier, Yannick [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); Hadjersi, Toufik [Centre de Recherche en Technologie des Semi-conducteurs pour l' Energétique-CRTSE 02, Bd Frantz Fanon, BP. 140, Alger 7 Merveilles (Algeria); Maamache, Mustapha [Laboratoire de Physique Quantique et Systèmes Dynamiques, Département de Physique, Université de Sétif, Sétif 19000 (Algeria); Szunerits, Sabine [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); and others

    2016-03-05

    Highlights: • Cr(VI) reduction to Cr(III) using silicon nanowires decorated with Cu nanoparticles. • The reduction takes place at room temperature and neutral pH under visible light. • The photocatalytic reduction was enhanced by addition of adipic or citric acid. - Abstract: We report an efficient visible light-induced reduction of hexavalent chromium Cr(VI) to trivalent Cr(III) by direct illumination of an aqueous solution of potassium dichromate (K{sub 2}Cr{sub 2}O{sub 7}) in the presence of hydrogenated silicon nanowires (H-SiNWs) or silicon nanowires decorated with copper nanoparticles (Cu NPs-SiNWs) as photocatalyst. The SiNW arrays investigated in this study were prepared by chemical etching of crystalline silicon in HF/AgNO{sub 3} aqueous solution. The Cu NPs were deposited on SiNW arrays via electroless deposition technique. Visible light irradiation of an aqueous solution of K{sub 2}Cr{sub 2}O{sub 7} (10{sup −4} M) in presence of H-SiNWs showed that these substrates were not efficient for Cr(VI) reduction. The reduction efficiency achieved was less than 10% after 120 min irradiation at λ > 420 nm. Addition of organic acids such as citric or adipic acid in the solution accelerated Cr(VI) reduction in a concentration-dependent manner. Interestingly, Cu NPs-SiNWs was found to be a very efficient interface for the reduction of Cr(VI) to Cr(III) in absence of organic acids. Almost a full reduction of Cr(VI) was achieved by direct visible light irradiation for 140 min using this photocatalyst.

  5. High-Wattage Pulsed Irradiation of Linearly Polarized Near-Infrared Light to Stellate Ganglion Area for Burning Mouth Syndrome

    Directory of Open Access Journals (Sweden)

    Yukihiro Momota

    2014-01-01

    Full Text Available The purpose of this study was to apply high-wattage pulsed irradiation of linearly polarized near-infrared light to the stellate ganglion area for burning mouth syndrome (BMS and to assess the efficacy of the stellate ganglion area irradiation (SGR on BMS using differential time-/frequency-domain parameters (D parameters. Three patients with BMS received high-wattage pulsed SGR; the response to SGR was evaluated by visual analogue scale (VAS representing the intensity of glossalgia and D parameters used in heart rate variability analysis. High-wattage pulsed SGR significantly decreased the mean value of VAS in all cases without any adverse event such as thermal injury. D parameters mostly correlated with clinical condition of BMS. High-wattage pulsed SGR was safe and effective for the treatment of BMS; D parameters are useful for assessing efficacy of SGR on BMS.

  6. Fabrication and different photoelectric responses of nanocrystalline ZnO film irradiated with UV and white light in dry air

    Science.gov (United States)

    Zou, Zhijun; Qiu, Yang; Xie, Changsheng; Xu, Jingjing; Luo, Yongsong; Wang, Chunlei; Yan, Hailong

    2015-09-01

    In this paper, nanocrystalline ZnO film with porous structure was successfully prepared on alumina substrate by the technology of screen printing and the subsequent heat treatment. The fundamental characteristics of the as-prepared sample were examined through XRD, FE-SEM, EDX and PL spectra measurements. Meanwhile, photoelectric responses of it were tested under UV and white light irradiation, respectively. Different photocurrent curves were obtained. Under UV light, the photocurrent with comparatively high amplitude of each cycle could mostly recover upon the light off. While for white light, the photocurrent with low amplitude just partially recovered when the light was turned off. This phenomenon indicated that, after the white light off, a large number of free electrons still remained within the materials. To calculate the amount of the remained free electrons, three photocurrent parameters, which are related to the density of free electrons in ZnO, were defined for the first time. Furthermore, the explanations for the different photoelectric responses of ZnO based on the double Schottky barrier model were also proposed.

  7. The photocatalytic degradation of methylene blue by green semiconductor films that is induced by irradiation by a light-emitting diode and visible light.

    Science.gov (United States)

    Yang, Chih-Chi; Doong, Ruey-An; Chen, Ku-Fan; Chen, Giin-Shan; Tsai, Yung-Pin

    2018-01-01

    This study develops a low-energy rotating photocatalytic contactor (LE-RPC) that has Cu-doped TiO2 films coated on stainless-steel rotating disks, to experimentally evaluate the efficiency of the degradation and decolorization of methylene blue (MB) under irradiation from different light sources (visible 430 nm, light-emitting diode [LED] 460 nm, and LED 525 nm). The production of hydroxyl radicals is also examined. The experimental results show that the photocatalytic activity of TiO2 that is doped with Cu2+ is induced by illumination with visible light and an LED. More than 90% of methylene blue at a 10 mg/L concentration is degraded after illumination by visible light (430 nm) for 4 hr at 20 rpm. This study also demonstrates that the quantity of hydroxyl radicals produced is directly proportional to the light energy intensity. The greater the light energy intensity, the greater is the number of hydroxyl radicals produced. The CuO-doped anatase TiO2 powder was successfully synthesized in this study by a sol-gel method. The catalytic abilities of the stainless-steel film were enhanced in the visible light regions. This study has successfully modified the nano-photocatalytic materials to drop band gap and has also successfully fixed the nano-photocatalytic materials on a substratum to effectively treat dye wastewater in the range of visible light. The results can be useful to the development of a low-energy rotating photocatalytic contactor for decontamination purposes.

  8. Synthesis of pyrrolnitrin and related halogenated phenylpyrroles.

    Science.gov (United States)

    Morrison, Matthew D; Hanthorn, Jason J; Pratt, Derek A

    2009-03-05

    A general approach to halogenated arylpyrroles, including the antifungal natural product pyrrolnitrin, is described using newly synthesized halogenated pyrroles and 2,6-disubstituted nitrobenzenes or 2,6-disubstituted anilines.

  9. Effect of irradiance and light source on contraction stress, degree of conversion and push-out bond strength of composite restoratives.

    Science.gov (United States)

    Cunha, Leonardo Gonçalves; Alonso, Roberta Caroline Bruschi; Pfeifer, Carmem Silvia Costa; de Góes, Mario Fernando; Ferracane, Jack Liborio; Sinhoreti, Mário Alexandre Coelho

    2009-06-01

    To evaluate the influence of five curing methods on contraction stress, stress rate, and degree of conversion (DC) of a composite and on bond strength of composite restoratives. For the stress test, composite was applied between two 5-mm diameter glass rods, mounted in a servohydraulic machine. Stress rates were calculated as the change in stress vs. time. DC was measured by FTIR. Bond strength testing was performed using a push-out test in bovine incisors. The C-factor was 3.0 for all tests. Five methods were evaluated: High Intensity LED (LED HI), Continuous Halogen Light (QTH CL), Medium Intensity LED (LED MI), Low Intensity LED (LED LI), and Pulse Delay Halogen Light (QTH PD). Results were analyzed by ANOVA and Tukey's test (alpha = 0.05). Stress values ranged from 9.25 MPa (QTH PD) to 10.46 MPa (LED MI). No statistical difference was observed among the methods. Bond strength values ranged from 24.6 MPa (LED HI) to 35.4 MPa (QTH PD), with the QTH PD presenting a statistically higher value compared to the other methods. Stress rate and bond strength presented an inverse linear correlation (r2 = 0.79). LED HI presented the highest maximum stress rate, followed by LED MI, QTH CL, LED LI, and QTH PD. The reduction in stress rate observed for the low intensity groups was associated with a general increase in bond strength, with no adverse effect on the degree of conversion of the restorative composite.

  10. 40 CFR 721.505 - Halogenated acrylonitrile.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated acrylonitrile. 721.505... Substances § 721.505 Halogenated acrylonitrile. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as halogenated acrylonitrile, (PMN P-90-299) is...

  11. Photodynamic inactivation of pathogenic species Pseudomonas aeruginosa and Candida albicans with lutetium (III) acetate phthalocyanines and specific light irradiation.

    Science.gov (United States)

    Mantareva, Vanya; Kussovski, Vesselin; Durmuş, Mahmut; Borisova, Ekaterina; Angelov, Ivan

    2016-11-01

    Photodynamic inactivation (PDI) is a light-associated therapeutic approach suitable for treatment of local acute infections. The method is based on specific light-activated compound which by specific irradiation and in the presence of molecular oxygen produced molecular singlet oxygen and other reactive oxygen species, all toxic for pathogenic microbial cells. The study presents photodynamic impact of two recently synthesized water-soluble cationic lutetium (III) acetate phthalocyanines (LuPc-5 and LuPc-6) towards two pathogenic strains, namely, the Gram-negative bacterium Pseudomonas aeruginosa and a fungus Candida albicans. The photodynamic effect was evaluated for the cells in suspensions and organized in 48-h developed biofilms. The relatively high levels of uptakes of LuPc-5 and LuPc-6 were determined for fungal cells compared to bacterial cells. The penetration depths and distribution of both LuPcs into microbial biofilms were investigated by means of confocal fluorescence microscopy. The photoinactivation efficiency was studied for a wide concentration range (0.85-30 μM) of LuPc-5 and LuPc-6 at a light dose of 50 J cm-2 from red light-emitting diode (LED; 665 nm). The PDI study on microbial biofilms showed incomplete photoinactivation (light protocol.

  12. Dermal toxicity of 8-methoxypsoralen administered (by gavage) to hairless mice irradiated with long-wave ultraviolet light

    Energy Technology Data Exchange (ETDEWEB)

    Langner, A.; Wolska, H.; Marzulli, F.N.; Jablonska, S.; Jarzabek-Chorzelska, M.; Glinski, W.; Pawinska, M.

    1977-11-01

    Hairless mice were administered various amounts of 8-methoxypsoralen (8-MOP) by gavage, followed by irradiation with ultraviolet light (UVA) two or more times per week for periods ranging from 1 to 12 months. The minimum phototoxic dose was 20 mg/kg body weight by this route of administration and potential for serious organ toxicity in long-term exposures was investigated. No histologic features of cutaneous malignancy were encountered under test conditions which produced prolonged phototoxicity, deep ulceration, cicatrization, and other deformities. Repeated daily gavaged doses of 20 mg psoralen/Kg body weight in conjunction with twice weekly irradiation for 10 min with UVA elicited an erythematous phototoxic reaction, but did not give rise to subsequent skin lesions. 8-MOP in repeated daily gavage doses of 30 mg and 40 mg/kg body weight combined with twice weekly UVA irradiation for 10 min caused severe burning with subsequent scarring, but did not induce malignant tumors in experiments lasting 8 months. No organ toxicity was seen except for toxic liver changes when severe cutaneous burn and pronounced ulcerations were produced. Limited immunologic studies disclosed no abnormalities in this system.

  13. Mechanical properties of SiC composites neutron irradiated under light water reactor relevant temperature and dose conditions

    Science.gov (United States)

    Koyanagi, Takaaki; Katoh, Yutai

    2017-10-01

    Silicon carbide (SiC) fiber-reinforced SiC matrix (SiC/SiC) composites are being actively investigated for use in accident-tolerant core structures of light water reactors (LWRs). Owing to the limited number of irradiation studies previously conducted at LWR-coolant temperature, this study examined SiC/SiC composites following neutron irradiation at 230-340 °C to 2.0 and 11.8 dpa in the High Flux Isotope Reactor. The investigated materials were chemical vapor infiltrated (CVI) SiC/SiC composites with three different reinforcement fibers. The fiber materials were monolayer pyrolytic carbon (PyC) -coated Hi-Nicalon™ Type-S (HNS), Tyranno™ SA3 (SA3), and SCS-Ultra™ (SCS) SiC fibers. The irradiation resistance of these composites was investigated based on flexural behavior, dynamic Young's modulus, swelling, and microstructures. There was no notable mechanical properties degradation of the irradiated HNS and SA3 SiC/SiC composites except for reduction of the Young's moduli by up to 18%. The microstructural stability of these composites supported the absence of degradation. In addition, no progressive swelling from 2.0 to 11.8 dpa was confirmed for these composites. On the other hand, the SCS composite showed significant mechanical degradation associated with cracking within the fiber. This study determined that SiC/SiC composites with HNS or SA3 SiC/SiC fibers, a PyC interphase, and a CVI SiC matrix retain their properties beyond the lifetime dose for LWR fuel cladding at the relevant temperature.

  14. Synthesis, Characterization and Photocatalytic Activity of New Photocatalyst ZnBiSbO4 under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Jingfei Luan

    2014-05-01

    Full Text Available In this paper, ZnBiSbO4 was synthesized by a solid-state reaction method for the first time. The structural and photocatalytic properties of ZnBiSbO4 had been characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, transmission electron microscope and UV-visible spectrometer. ZnBiSbO4 crystallized with a pyrochlore-type structure and a tetragonal crystal system. The band gap of ZnBiSbO4 was estimated to be 2.49 eV. The photocatalytic degradation of indigo carmine was realized under visible light irradiation with ZnBiSbO4 as a catalyst compared with nitrogen-doped TiO2 (N-TiO2 and CdBiYO4. The results showed that ZnBiSbO4 owned higher photocatalytic activity compared with N-TiO2 or CdBiYO4 for the photocatalytic degradation of indigo carmine under visible light irradiation. The reduction of the total organic carbon, the formation of inorganic products, SO42− and NO3−, and the evolution of CO2 revealed the continuous mineralization of indigo carmine during the photocatalytic process. One possible photocatalytic degradation pathway of indigo carmine was obtained. The phytotoxicity of the photocatalytic-treated indigo carmine (IC wastewater was detected by examining its effect on seed germination and growth.

  15. Synthesis, Characterization and Photocatalytic Activity of New Photocatalyst ZnBiSbO4 under Visible Light Irradiation

    Science.gov (United States)

    Luan, Jingfei; Chen, Mengjing; Hu, Wenhua

    2014-01-01

    In this paper, ZnBiSbO4 was synthesized by a solid-state reaction method for the first time. The structural and photocatalytic properties of ZnBiSbO4 had been characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, transmission electron microscope and UV-visible spectrometer. ZnBiSbO4 crystallized with a pyrochlore-type structure and a tetragonal crystal system. The band gap of ZnBiSbO4 was estimated to be 2.49 eV. The photocatalytic degradation of indigo carmine was realized under visible light irradiation with ZnBiSbO4 as a catalyst compared with nitrogen-doped TiO2 (N-TiO2) and CdBiYO4. The results showed that ZnBiSbO4 owned higher photocatalytic activity compared with N-TiO2 or CdBiYO4 for the photocatalytic degradation of indigo carmine under visible light irradiation. The reduction of the total organic carbon, the formation of inorganic products, SO42− and NO3−, and the evolution of CO2 revealed the continuous mineralization of indigo carmine during the photocatalytic process. One possible photocatalytic degradation pathway of indigo carmine was obtained. The phytotoxicity of the photocatalytic-treated indigo carmine (IC) wastewater was detected by examining its effect on seed germination and growth. PMID:24879521

  16. Photocatalytic degradation of indigo carmine by ZnO photocatalyst under visible light irradiation

    Directory of Open Access Journals (Sweden)

    Ali Al- Taie

    2017-09-01

    Full Text Available In this work, the photocatalytic degradation of indigo carmine (IC using zinc oxide suspension was studied. The effect of influential parameters such as initial indigo carmine concentration and catalyst loading were studied with the effect of Vis irradiation in the presence of reused ZnO was also investigated. The increased in initial dye concentration decreased the photodegradation and the increased catalyst loading increased the degradation percentage and the reused-ZnO exhibits lower photocatalytic activity than the ZnO catalyst. It has been found that the photocatalytic degradation of indigo carmine obeyed the pseudo-first-order kinetic reaction in presence of zinc oxide. This was found from plotting the relationship between ln (C0/Ct and irradiation the rate constant of the process.UV- spectrophotometer was used to study the indigo carmine photodegradation

  17. Infrared spectroscopy of laser-irradiated dental hard tissues using the Advanced Light Source

    Science.gov (United States)

    Fried, Daniel; Breunig, Thomas

    2001-04-01

    FTIR spectroscopy used in the specular reflectance mode is well suited for resolving thermally induced changes in dental hard tissue as a result of laser irradiation. High spatial resolution is achievable with a high brightness synchrotron radiation source such as the ALS at Lawrence Berkeley National Laboratory. IR spectra of modified enamel were acquired after laser ablation using several laser wavelengths from the UV to the mid-IR. Specific areas of laser ablation craters were probed non-destructively with 10-micrometers spatial resolution. The chemical composition of the crater walls deviates markedly from that of hydroxyapatite after Er:YAG and CO2 laser irradiation without added water. New mineral phases were resolved that have not been previously observed using conventional IR spectroscopy.

  18. LIGHT SOURCE: Terahertz emission in tenuous gases irradiated by ultrashort laser pulses

    Science.gov (United States)

    Wang, Wei-Min; Sheng, Zheng-Ming; Wit, Hui-Chun; Chen, Min; Li, Chun; Zhang, Jie; Mima, K.

    2009-06-01

    Mechanism of terahertz (THz) pulse generation in gases irradiated by ultrashort laser pulses is investigated theoretically. Quasi-static transverse currents produced by laser field ionization of gases and the longitudinal modulation in formed plasmas are responsible for the THz emission at the electron plasma frequency, as demonstrated by particle-in-cell simulations including field ionization. The THz field amplitude scaling with the laser amplitude within a large range is also discussed.

  19. Organic halogens in landfill leachates

    DEFF Research Database (Denmark)

    Grøn, C.; Christensen, J. B.; Jensen, Dorthe Lærke

    2000-01-01

    compounds behind the high TOX could not be found. Conversely, part of the TOX could be attributed to halogenated humic substances that can not be analysed with conventional organic contaminant analyses. Even though TOX can still be considered an indicator of leachate contamination in the aquifers, attempts...

  20. Effect of 710 nm visible light irradiation on neurite outgrowth in primary rat cortical neurons following ischemic insult

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Dong-Hee [Center for Neuroscience Research, SMART Institute of Advanced Biomedical Science, Konkuk University, Seoul (Korea, Republic of); Department of Medical Science, Konkuk University School of Medicine, Seoul (Korea, Republic of); Lee, Kyoung-Hee; Kim, Ji-Hye; Kim, Moon Young [Center for Neuroscience Research, SMART Institute of Advanced Biomedical Science, Konkuk University, Seoul (Korea, Republic of); Lim, Jeong Hoon [Department of Rehabilitation Medicine, Konkuk University School of Medicine, Seoul (Korea, Republic of); Rehabilitation Medicine, Division of Neurology, Department of Medicine, National University Hospital, National University Health System (Singapore); Lee, Jongmin, E-mail: leej@kuh.ac.kr [Center for Neuroscience Research, SMART Institute of Advanced Biomedical Science, Konkuk University, Seoul (Korea, Republic of); Department of Rehabilitation Medicine, Konkuk University School of Medicine, Seoul (Korea, Republic of)

    2012-06-01

    Highlights: Black-Right-Pointing-Pointer 710 nm wavelength light (LED) has a protective effect in the stroke animal model. Black-Right-Pointing-Pointer We determined the effects of LED irradiation in vitro stroke model. Black-Right-Pointing-Pointer LED treatment promotes the neurite outgrowth through MAPK activation. Black-Right-Pointing-Pointer The level of synaptic markers significantly increased with LED treatment. Black-Right-Pointing-Pointer LED treatment protects cell death in the in vitro stroke model. -- Abstract: Objective: We previously reported that 710 nm Light-emitting Diode (LED) has a protective effect through cellular immunity activation in the stroke animal model. However, whether LED directly protects neurons suffering from neurodegeneration was entirely unknown. Therefore, we sought to determine the effects of 710 nm visible light irradiation on neuronal protection and neuronal outgrowth in an in vitro stroke model. Materials and methods: Primary cultured rat cortical neurons were exposed to oxygen-glucose deprivation (OGD) and reoxygenation and normal conditions. An LED array with a peak wavelength of 710 nm was placed beneath the covered culture dishes with the room light turned off and were irradiated accordingly. LED treatments (4 min at 4 J/cm{sup 2} and 50 mW/cm{sup 2}) were given once to four times within 8 h at 2 h intervals for 7 days. Mean neurite density, mean neurite diameter, and total fiber length were also measured after microtubule associated protein 2 (MAP2) immunostaining using the Axio Vision program. Synaptic marker expression and MAPK activation were confirmed by Western blotting. Results: Images captured after MAP2 immunocytochemistry showed significant (p < 0.05) enhancement of post-ischemic neurite outgrowth with LED treatment once and twice a day. MAPK activation was enhanced by LED treatment in both OGD-exposed and normal cells. The levels of synaptic markers such as PSD 95, GAP 43, and synaptophysin significantly

  1. ZnO:SnO nanorods and nanosheets and their enhanced photocatalytic activity under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Harish, S., E-mail: aravindharri@gmail.com, E-mail: suruponnus@gmail.com; Ponnusamy, S., E-mail: aravindharri@gmail.com, E-mail: suruponnus@gmail.com; Muthamizhchelvan, C. [Centre for Nanoscience and Nanotechnology, Department of Physics, SRM University, Kattankulathur, Chennai, 603203, Tamil Nadu (India); Silambarasan, A. [Department of Chemistry, SRM University, Ramapuram, Chennai, 600089, Tamil Nadu (India); Navaneethan, M.; Archana, J.; Hayakawa, Y. [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8011 (Japan)

    2015-06-24

    ZnO-SnO nanocomposites were synthesized by a simple hydrothermal method. It was found that Sn concentration acted as a crucial factor in determining the morphology of ZnO-SnO nanostructures, in the presence of ethylenediamine (EDA) as a stabilizing agent. XRD analysis confirmed the formation of ZnO and SnO with good crystallinity. The morphological analysis revealed tin oxide (SnO) nanoparticles coated on the surface of ZnO nanorods and nanosheets. The photocatalytic activity of synthesized samples were evaluated by methylene blue (MB) as a model pollutant under visible light irradiation. Photocatalysis studies revealed that, ZnO-SnO nanocomposites show the enhanced photocatalytic activity compared to ZnO, which could be attributed to the formation of hetero-junction between ZnO and SnO of MB degradation. Sn concentration can extend the light absorption spectra of ZnO to visible light region and enhance the visible light photocatalytic activity. This research could provide new insights to the development of excellent photocatalyst with efficient performance for pollution control.

  2. Halogen Bonding in Nucleic Acid Complexes.

    Science.gov (United States)

    Kolář, Michal H; Tabarrini, Oriana

    2017-11-09

    Halogen bonding (X-bonding) has attracted notable attention among noncovalent interactions. This highly directional attraction between a halogen atom and an electron donor has been exploited in knowledge-based drug design. A great deal of information has been gathered about X-bonds in protein-ligand complexes, as opposed to nucleic acid complexes. Here we provide a thorough analysis of nucleic acid complexes containing either halogenated building blocks or halogenated ligands. We analyzed close contacts between halogens and electron-rich moieties. The phosphate backbone oxygen is clearly the most common halogen acceptor. We identified 21 X-bonds within known structures of nucleic acid complexes. A vast majority of the X-bonds is formed by halogenated nucleobases, such as bromouridine, and feature excellent geometries. Noncovalent ligands have been found to form only interactions with suboptimal interaction geometries. Hence, the first X-bonded nucleic acid binder remains to be discovered.

  3. Photoelectrocatalytic degradation of methylene blue using F doped TiO2photoelectrode under visible light irradiation.

    Science.gov (United States)

    Liu, Dong; Tian, Renwen; Wang, Jianqiao; Nie, Er; Piao, Xianqing; Li, Xin; Sun, Zhuo

    2017-10-01

    Photoelectrocatalysis (PEC) has attracted great interest due to cost effectiveness and high efficiency in water treatment. In this study, F doped TiO 2 (F-TiO 2 ) photoelectrodes with honeycomb like morphology were prepared, and the PEC performance was investigated. F-TiO 2 particles that showed enhanced absorption of visible light were synthesized via a sol-gel method. F-TiO 2 particles were anchored onto the surface of F-doped SnO 2 glass by a screen-printing method to prepare the F-TiO 2 photoelectrodes. The PEC performance of the F-TiO 2 photoelectrodes was investigated via the degradation of methylene blue (MB) under visible light irradiation. The results show that the F-TiO 2 photoelectrodes exhibited an excellent PEC performance that was affected by the F doping content, applied bias and solution pH. A maximum decolorization percentage of 97.8% was achieved by the FT-15 photoelectrode, with a 1.4 V bias at pH 9.94 after 4.0 h of visible light irradiation. The high PEC performance of the F-TiO 2 photoelectrodes is mainly ascribed to the efficient separation of electron-hole (e - -h + ) pairs and the creation of active radicals such as hydroxyl radicals (OH). The PEC decolorization kinetic data were analyzed using the first-order kinetic model and the Langmuir-Hinshelwood (L-H) model. The data indicates that the PEC degradation of MB molecules mainly occurred on the surface of the F-TiO 2 photoelectrodes, and the MB molecules were discolored mainly by h + (41.5%) and OH (46.5%). In addition, 8.2% of the MB molecules were discolored by other oxidative species, and 3.8% of the MB molecules were discolored by self-sensitized oxidation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Basic study of charring detection at the laser catheter-tip using back scattering light measurement during therapeutic laser irradiation in blood.

    Science.gov (United States)

    Takahashi, Mei; Ito, Arisa; Kajihara, Takuro; Matsuo, Hiroki; Arai, Tsunenori

    2010-01-01

    The purpose of this study is to investigate transient process of the charring at the laser catheter-tip in blood during therapeutic laser irradiation by the back scattering light measurement to detect precursor state of the charring. We took account of using photodynamic therapy for arrhythmia in blood through the laser catheter. We observed the influence of the red laser irradiation (λ=663 nm) upon the shape of red blood cells (RBCs). The RBCs aggregation, round formation, and hemolysis were took place sequentially before charring. With a model blood sandwiched between glass plates simulated as a catheter-tip boundary, we measured diffuse-reflected-light power and transmitted-light power simultaneously and continuously by a microscopic optics during the laser irradiation. We found that measured light power changes were originated with RBCs shape change induced by temperature rise due to the laser irradiation. A gentle peak following a slow descending was observed in the diffuse-reflected-light power history. This history might indicate the precursor state of the charring, in which the hemolysis might be considered to advance rapidly. We think that the measurement of diffuse-reflected-light power history might be able to detect precursor state of charring at the catheter-tip in blood.

  5. A photo-auxiliary approach - enabling excited state classical phototransformations with metal free visible light irradiation.

    Science.gov (United States)

    Iyer, Akila; Jockusch, Steffen; Sivaguru, Jayaraman

    2017-02-04

    Most traditional photoreactions require UV light to yield the desired product. To address this issue, photoreaction of hydrazide based chromophores was evaluated with visible light using a metal free photocatalyst to afford photoproducts in high yields. This hydrazide functionality itself may be removed/modified after the photoreaction, highlighting its role as a "photo-auxiliary". A preliminary mechanistic model based on photophysical experiments is provided to highlight the generality of the strategy.

  6. Electron spin resonance of melanin from hair. Effects of temperature, pH and light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Arnaud, R.; Perbet, G. (Clermont-Ferrand-2 Univ., 63 - Aubiere (France)); Deflandre, A.; Lang, G. (Centre de Recherches de la Societe L' Oreal, Aulnay Sous Bois (France) Dept. de Chimie Generale)

    1983-08-01

    The variation with temperature, pH and light of the ESR signal of hydrated melanin powders from Japanese black hair has been studied. An explanation of the results is proposed on the basis of quinhydrone type complexes and of acid-base equilibria of melanin and its semiquinone radicals. During exposure to light of wavelengths 254-600 nm, both stable and unstable radicals have been observed. The action spectrum for the formation of stable melanin radicals has been determined.

  7. Development of Temperature Distribution and Light Propagation Model in Biological Tissue Irradiated by 980 nm Laser Diode and Using COMSOL Simulation.

    Science.gov (United States)

    Shurrab, Kawthar; Kochaji, Nabil; Bachir, Wesam

    2017-01-01

    Introduction: The purpose of this project is to develop a mathematical model to investigate light distribution and study effective parameters such as laser power and irradiated time to get the optimal laser dosage to control hyperthermia. This study is expected to have a positive impact and a better simulation on laser treatment planning of biological tissues. Moreover, it may enable us to replace animal tests with the results of a COMSOL predictive model. Methods: We used in this work COMSOL5 model to simulate the light diffusion and bio-heat equation of the mouse tissue when irradiated by 980 nm laser diode and the effect of different parameters (laser power, and irradiated time) on the surrounding tissue of the tumor treatment in order to prevent damage from excess heat Results: The model was applied to study light propagation and several parameters (laser power, irradiated time) and their impact on light-heat distribution within the tumor in the mouse back tissue The best result is at laser power 0.5 W and time irradiation 0.5 seconds in order to get the maximum temperature hyperthermia at 52°C. Conclusion: The goal of this study is to simulate a mouse model to control excess heating of tissue and reduce the number of animals in experimental research to get the best laser parameters that was safe for use in living animals and in human subjects.

  8. A two-step photoexcitation system for photocatalytic water splitting into hydrogen and oxygen under visible light irradiation

    Science.gov (United States)

    Abe, Ryu

    2011-10-01

    The developments of water-splitting systems that can efficiently use visible light have been a major challenge for many years in order to realize efficient conversion of solar light. We have developed a new type of photocatalysis system that can split water into H2 and O2 under visible light irradiation, which was inspired by the two-step photoexcitation (Zscheme) mechanism of natural photosynthesis in green plants. In this system, the water splitting reaction is broken up into two stages: one for H2 evolution and the other for O2 evolution; these are combined by using a shuttle redox couple (Red/Ox) in the solution. The introduction of a Z-scheme mechanism reduces the energy required to drive each photocatalysis process, extending the usable wavelengths significantly (~460 nm for H2 evolution and ~600 nm for O2evolution) from that in conventional water splitting systems (~460 nm) based on one-step photoexcitation in single semiconductor material.

  9. Spectral effects on Symbiodinium photobiology studied with a programmable light engine.

    Directory of Open Access Journals (Sweden)

    Daniel Wangpraseurt

    Full Text Available The spectral light field of Symbiodinium within the tissue of the coral animal host can deviate strongly from the ambient light field on a coral reef and that of artificial light sources used in lab studies on coral photobiology. Here, we used a novel approach involving light microsensor measurements and a programmable light engine to reconstruct the spectral light field that Symbiodinium is exposed to inside the coral host and the light field of a conventional halogen lamp in a comparative study of Symbiodinium photobiology. We found that extracellular gross photosynthetic O2 evolution was unchanged under different spectral illumination, while the more red-weighted halogen lamp spectrum decreased PSII electron transport rates and there was a trend towards increased light-enhanced dark respiration rates under excess irradiance. The approach provided here allows for reconstructing and comparing intra-tissue coral light fields and other complex spectral compositions of incident irradiance. This novel combination of sensor technologies provides a framework to studying the influence of macro- and microscale optics on Symbiodinium photobiology with unprecedented spectral resolution.

  10. Optimal I-V Curve Scan Time of Solar Cells and Modules in Light of Irradiance Level

    Directory of Open Access Journals (Sweden)

    Matic Herman

    2012-01-01

    Full Text Available High-efficiency solar cells and modules exhibit strong capacitive character resulting in limited speed of transient responses. A too fast I-V curve measurement can thus introduce a significant error due to its internal capacitances. This paper analyses the I-V curve error of a measured solar cell or module in light of scan time and irradiance level. It rests on a two-diode solar cell model extended by two bias-dependent capacitances, modelling the junction, and the diffusion capacitance. A method for determination of all extended model parameters from a quasistatic I-V curve and open-circuit voltage decay measurement is presented and validated. Applicability of the extended model and the developed parameter extraction method to PV modules is demonstrated and confirmed. SPICE simulations of the extended model are used to obtain the I-V curve error versus scan time dependence and the I-V curve hysteresis. Determination of the optimal scan time is addressed, and finally the influence of the irradiance level on the I-V curve scan time and error is revealed. The method is applied but is not limited to three different wafer-based silicon solar cell types.

  11. Spectroscopic analysis of porphyrin compounds irradiated with visible light in chloroform with addition of β-myrcene

    Science.gov (United States)

    Makarska-Bialokoz, Magdalena; Gladysz-Plaska, Agnieszka

    2016-12-01

    The behaviour of two porphyrins, 5,10,15,20-tetraphenyl-21H,23H-porphine (H2TPP) and 5,10,15,20-tetra(4-pyridyl)-21H, 23H-porphine (H2TPyP), as well as their Zn(II) complexes (ZnTPP and ZnTPyP), have been studied analysing their absorption and steady-state fluorescence spectra in chloroform with addition of β-myrcene. After irradiation with visible light the free-base porphyrins have been converted to the form of dication on account of hydrochloric acid generated as a result of chloroform decomposition induced by β-myrcene. Whereas in case of their Zn(II) complexes the mechanism of action is more complicated, leading presumably to the formation of the aggregated metalloporphyrin species with chloride ions playing the bridging role. The pseudo-first-order rate constants of the absorption quenching process were calculated for all the systems examined, with respect to the porphyrin concentration. The most effective irradiation was observed in case of H2TPP porphyrin.

  12. Photodegradation of dye pollutants catalyzed by γ-Bi2MoO6 nanoplate under visible light irradiation

    Science.gov (United States)

    Zhao, Xu; Xu, Tongguang; Yao, Wenqing; Zhu, Yongfa

    2009-06-01

    Nanoplate γ-Bi 2MoO 6 is prepared by hydrothermal method. Using this material as photocatalyst, rhodamine B and methylene blue were efficiently degraded under visible light irradiation. The degradation kinetics, total organic carbon changes, and electron spin resonance detection of active oxygen species were investigated to clarify the degradation process. The experimental results indicated that the target dyes could be facilely bleached and mineralized. The formation of active oxygen species of rad OH and O 2rad - is detected, and they are proposed to be responsible for the degradation of the target dyes. The γ-Bi 2MoO 6 catalyst is very stable and can be reused.

  13. Effect of PdS on Photocatalytic Hydrogen Evolution of Nanostructured CdS under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Qingyun Chen

    2013-01-01

    Full Text Available To investigate the effect of PdS as a cocatalyst for photocatalytic hydrogen evolution, nanostructured PdS/CdS were prepared by an in situ coprecipitation and hydrothermal method, respectively. The as-prepared photocatalysts were characterized by transmission electron microscopy (TEM, X-ray diffraction (XRD, UV-visible absorption spectra, and photoluminescence spectra (PL. With PdS highly dispersed in the CdS nanostructures, the photoactivity was evaluated by hydrogen evolution from aqueous solution containing Na2S/Na2SO3 as sacrificial reagents under visible light irradiation. When the concentration of PdS was 1% by weight, PdS/CdS, prepared by the in situ coprecipitation, showed the highest photocatalytic activity, while that prepared by hydrothermal method showed the most stability for hydrogen evolution. The effect of highly dispersed PdS on the photoactivity was discussed.

  14. Graphene supported silver@silver chloride & ferroferric oxide hybrid, a magnetically separable photocatalyst with high performance under visible light irradiation

    Science.gov (United States)

    Zhong, Suting; Jiang, Wei; Han, Mei; Liu, Gongzong; Zhang, Na; Lu, Yue

    2015-08-01

    A stable magnetic separable plasmonic photocatalyst was successfully fabricated by grafting silver@silver chloride (Ag@AgCl) and ferroferric oxide (Fe3O4) nanoparticles on graphene sheets. The composite exhibited high activity degrading methylene blue (MB) and rhodamine B (RB) under visible light irradiation: decomposition 97.4% of MB in 100 min and 97.9% of RB in 120 min. The enhanced photocatalytic activities can be attributed to synergistic effect between Ag@AgCl and graphene: the effective charge transfer from Ag@AgCl to graphene thus promotes the separation of electron-hole pairs. Moreover, the excellent magnetic property gives a more convenient way to recycle the photocatalysts.

  15. High sensitivity ethanol gas sensor based on Sn - doped ZnO under visible light irradiation at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Peishuo; Pan, Guofeng; Zhang, Bingqiang; Zhen, Jiali; Sun, Yicai, E-mail: pgf@hebut.edu.cn [Institute of Microelectronic, Hebei University of Technology, Tianjin (China)

    2014-07-15

    Pure ZnO and 5at%, 7at%, 9at% Sn - doped ZnO materials are prepared by the chemical co - precipitation method. They were annealed by furnace at temperature range of 300 - 700ºC in air for 1h. The ZnO materials are characterized by X - ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the Sn - doped ZnO materials appear rough porous structures. The maximum sensitivity can be achieved by doping the amount of 7 at%. It has much better sensing performance towards ethanol vapor under visible light irradiation. The response and recovery time are ~1s and ~5s, respectively. The mechanism for the improvement in the sensing properties can be explained with the surface adsorption theory and the photoactivation theory. (author)

  16. A bifunctionalized dye-sensitized TiO(2) film for efficient degradation of methyl orange under visible light irradiation.

    Science.gov (United States)

    Wu, Quanping; Zhao, Jun; Qin, Guohui; Wang, Xuezheng; Tong, Xinli; Xue, Song

    2012-01-01

    A new bifunctionalized TiO(2) film containing a dye-sensitized region and a degradation region was described. A similar structure of dye-sensitized solar cell (DSSC) was fabricated in the dye-sensitized region to accomplish separation of electrons from positive charges, and separation of dye from pollutants to avoid dye decomposition. The bifunctionalized TiO(2) film electrode and anode electrode can degrade methyl orange (MO) in reactors A and B, respectively. The degradation efficiency was enhanced remarkably by an external electrical potential. The decolorization of MO reaches as high as 95% after 2 h visible light irradiation at an external potential of 0.5 V along with a loss of 41% total organic carbon (TOC). The possible reason for the improvement of degradation by external DC potential was discussed. Effects of pH and inorganic salts on the decolorization are present.

  17. Visible-Light-Irradiated Graphitic Carbon Nitride Photocatalyzed Diels-Alder Reactions with Dioxygen as Sustainable Mediator for Photoinduced Electrons.

    Science.gov (United States)

    Zhao, Yubao; Antonietti, Markus

    2017-08-01

    Photocatalytic Diels-Alder (D-A) reactions with electron rich olefins are realized by graphitic carbon nitride (g-C3 N4 ) under visible-light irradiation and aerobic conditions. This heterogeneous photoredox reaction system is highly efficient, and the apparent quantum yield reaches a remarkable value of 47 % for the model reaction. Dioxygen plays a critical role as electron mediator, which is distinct from the previous reports in the homogeneous RuII complex photoredox system. Moreover, the reaction intermediate vinylcyclobutane is captured and monitored during the reaction, serving as a direct evidence for the proposed reaction mechanism. The cycloaddition process is thereby determined to be the combination of direct [4+2] cycloaddition and [2+2] cycloaddition followed by photocatalytic rearrangement of the vinylcyclobutane intermediate. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Dissipative and Autonomous Square-Wave Self-Oscillation of a Macroscopic Hybrid Self-Assembly under Continuous Light Irradiation.

    Science.gov (United States)

    Ikegami, Tomonori; Kageyama, Yoshiyuki; Obara, Kazuma; Takeda, Sadamu

    2016-07-11

    Building a bottom-up supramolecular system to perform continuously autonomous motions will pave the way for the next generation of biomimetic mechanical systems. In biological systems, hierarchical molecular synchronization underlies the generation of spatio-temporal patterns with dissipative structures. However, it remains difficult to build such self-organized working objects via artificial techniques. Herein, we show the first example of a square-wave limit-cycle self-oscillatory motion of a noncovalent assembly of oleic acid and an azobenzene derivative. The assembly steadily flips under continuous blue-light irradiation. Mechanical self-oscillation is established by successively alternating photoisomerization processes and multi-stable phase transitions. These results offer a fundamental strategy for creating a supramolecular motor that works progressively under the operation of molecule-based machines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Decoloration of organic dyes using zeolites supported Fe-doped ZnO under UV light irradiation

    Science.gov (United States)

    Pratiwi, M. I.; Afifah, N.; Saleh, R.

    2017-07-01

    Various weight percentages of natural zeolite (10 % - 40 %) had been coupled into Fe-doped ZnO (Fe:ZnO) nanoparticles using the co-precipitation method. The photocatalytic acivity of Fe:ZnO/Zeolites nanocomposites was monitored under UV light irradiation in decoloring methylene blue and methyl orange. The result shows that certain amount of natural zeolite in Fe:ZnO could increase the photocatalytic activity of the nanocomposites. The synthesized samples were characterized using some measurements such as Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), and Brunauer-Emment-Tellet (BET) surface area analysis. The FTIR spectra of the samples show the existance of zeolites in the samples. XRD patterns show that no crystal structure changes in ZnO after doping with Fe and supported with zeolites.

  20. Methylene blue photocatalysis in the presence of bismuth oxide under UV and solar light irradiation

    Directory of Open Access Journals (Sweden)

    Vanessa Rocha Liberatti

    2014-05-01

    Full Text Available Bismuth oxide (Bi2O3, an n-type semiconductor has been satisfactorily investigated for photocatalytic organic contaminant remediation. The Bi2O3 was prepared by solution combustion synthesis (SCS using as the oxidizing bismuth nitrate in acidic medium and urea as fuel. The influence of the type of synthesis on the photocatalytic properties of the oxide formed was investigated by XRD. From the diffractograms was verified that the materials obtained are predominantly of Bi2O3 crystals, it is possible to identify a sample with two crystalline phases, monoclinic (α-Bi2O3 and tetragonal (β-Bi2O3, and the other with only the monoclinic (α-Bi2O3. The two-phase oxide showed higher photocatalytic activity for discoloration of methylene blue under UV irradiation (60.59% and under sunlight (61.64% in 664 nm, followed kinetic law of pseudo-first order.

  1. Gas-Phase Photochemical Overall H2S Splitting by UV Light Irradiation.

    Science.gov (United States)

    Baldovi, Herme G; Albero, Josep; Ferrer, Belen; Mateo, Diego; Alvaro, Mercedes; García, Hermenegildo

    2017-05-09

    Splitting of hydrogen sulfide is achieved to produce value-added chemicals. Upon irradiation at 254 nm in the gas phase and in the absence of catalysts or photocatalysts at near room temperature, H 2 S splits into stoichiometric amounts of H 2 and S with a quantum efficiency close to 50 %. No influence of the presence of CH 4 and CO 2 (typical components in natural gas and biogas in which H 2 S is an unwanted component) on the efficiency of overall H 2 S splitting was observed. A mechanism for the H 2 and S formation is proposed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Irradiation of platelets with UV-B light exposes fibrinogen binding sites via an intracellular mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Marwijk Kooy, M. van; Borghuis, L.; Prooijen, H.C. van; Aarts-Riemens, M.I.; Akkerman, J.W.N. (Rijksuniversiteit Utrecht (Netherlands). Academisch Ziekenhuis)

    1990-12-01

    This study provides evidence that UV-B induced aggregation is mediated by a Ca{sup 2+}-dependent process of fibrinogen binding to an intact glycoprotein IIb-IIIa complex on platelet membranes. Although UV-induced platelet aggregation is independent of thromboxane A{sub 2} formation and ADP secretion, it requires metabolic energy, cytosolic Ca{sup 2+} and a low cyclic-AMP level. Thus, UV-B irradiation causes platelet aggregation by exposing fibrinogen binding sites via an intracellular mechanism. Since the amount of bound fibrinogen following UVI is relatively low (about 2300 molecules/platelet) and the binding remains reversible, its effect on platelet behaviour after transfusion may be minor. (author).

  3. Photocatalytic synthesis of anilides from nitrobenzenes under visible light irradiation: 2 in 1 reaction.

    Science.gov (United States)

    Zand, Zahra; Kazemi, Foad; Partovi, Adel

    2015-11-01

    An efficient method has been developed for the synthesis of a series of anilides via a two in one reaction of nitrobenzenes with anhydride in the presence of TiO2 as a nanocatalyst and photocatalyst under sunlight or blue LED irradiation. In this method simultaneously, nitrobenzenes convert to the corresponding anilines via photocatalytic reduction on the TiO2 surface, and a condensation of aniline with the anhydride performed on the Lewis acid site of the TiO2 surface. Interestingly amidation step leads to the promotion of better reaction and good selectivity in reduction of nitrocompounds. This method is simple, rapid, high yield, and green. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. The behaviour of microtubules in chromosomal spindle fibres irradiated singly or doubly with ultraviolet light

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, P.; Forer, A. (York Univ. (UK))

    1989-12-01

    Areas of reduced birefringence (ARBs) produced by ultraviolet microbeam irradiation are areas of depolymerized microtubules. The authors tested the theories that ARBs move poleward either by microtubule subunit addition at the kinetochore and loss at the pole, or by microtubule subunit addition at one edge of the ARB and loss from the other edge. They found that the two edges of the ARB move at the same rate about half the time. They also studied the behaviour of the ARBs on a single fibre and found that after two ARBs are formed on a single fibre, the region between the ARBs is unstable and rapidly depolymerizes. The results do not fit either model and suggest that influences of kinetochores and poles or other factors should be considered that are not duplicated in experiments on microtubules in vitro. (author).

  5. Spatial distribution of leaf nitrogen and photosynthetic capacity within the foliage of individual trees: disentangling the effects of local light quality, leaf irradiance, and transpiration.

    Science.gov (United States)

    Frak, Ela; Le Roux, Xavier; Millard, Peter; Adam, Boris; Dreyer, Erwin; Escuit, Cynthia; Sinoquet, Hervé; Vandame, Marc; Varlet-Grancher, Claude

    2002-11-01

    There is presently no consensus about the factor(s) driving photosynthetic acclimation and the intra-canopy distribution of leaf characteristics under natural conditions. The impact was tested of local (i) light quality (red/far red ratio), (ii) leaf irradiance (PPFD(i)), and (iii) transpiration rate (E) on total non-structural carbohydrates per leaf area (TNC(a)), TNC-free leaf mass-to-area ratio (LMA), total leaf nitrogen per leaf area (N(a)), photosynthetic capacity (maximum carboxylation rate and light-saturated electron transport rate), and leaf N partitioning between carboxylation and bioenergetics within the foliage of young walnut trees grown outdoors. Light environment (quantity and quality) was controlled by placing individual branches under neutral or green screens during spring growth, and air vapour pressure deficit (VPD) was prescribed and leaf transpiration and photosynthesis measured at branch level by a branch bag technique. Under similar levels of leaf irradiance, low air vapour pressure deficit decreased transpiration rate but did not influence leaf characteristics. Close linear relationships were detected between leaf irradiance and leaf N(a), LMA or photosynthetic capacity, and low R/FR ratio decreased leaf N(a), LMA and photosynthetic capacity. Irradiance and R/FR also influenced the partitioning of leaf nitrogen into carboxylation and electron light transport. Thus, local light level and quality are the major factors driving photosynthetic acclimation and intra-canopy distribution of leaf characteristics, whereas local transpiration rate is of less importance.

  6. Wavelength-sensitive photocatalytic degradation of methyl orange in aqueous suspension over iron(III)-doped TiO2 nanopowders under UV and visible light irradiation.

    Science.gov (United States)

    Wang, X H; Li, J-G; Kamiyama, H; Moriyoshi, Y; Ishigaki, T

    2006-04-06

    Well-crystallized iron(III)-doped TiO2 nanopowders with controlled Fe3+ doping concentration and uniform dopant distribution, have been synthesized with plasma oxidative pyrolysis. The photocatalytic reactivity of the synthesized TiO2 nanopowders with a mean particle size of 50-70 nm was quantified in terms of the degradation rates of methyl orange (MO) in aqueous TiO2 suspension under UV (mainly 365 and 316 nm) and visible light irradiation (mainly 405 and 436 nm). The photodecomposition of MO over TiO2 nanopowders followed a distinct two-stage pseudo first order kinetics. Interestingly, the photocatalytic reactivity depends not only on the iron doping concentration but also on the wavelength of the irradiating light. Under UV irradiation, nominally undoped TiO2 had much higher reactivity than Fe3+ -doped TiO2, suggesting that Fe3+ doping (> 0.05 at. %) in TiO2 with a mean particle size of approximately 60 nm was detrimental to the photocatalytic decomposition of methyl orange. Whereas, under visible light irradiation, the Fe3+ -doped TiO2 with an intermediate iron doping concentration of approximately 1 at. % had the highest photocatalytic reactivity due to the narrowing of band gap so that it could effectively absorb the light with longer wavelength. A strategy for improving the photocatalytic reactivity of Fe3+ -doped TiO2 used in the visible light region is also proposed.

  7. Effect of FeWO{sub 4} doping on the photocatalytic activity of ZnO under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Buvaneswari, K. [P.G. Department of Chemistry, Sir S. Ramasamy Naidu Memorial College, Sattur 626203, Tamilnadu (India); Karthiga, R.; Kavitha, B. [P.G. & Research Department of Chemistry, C.P.A. College, Bodinayakanur 625513, Tamilnadu (India); Rajarajan, M., E-mail: rajarajan_1962@yahoo.com [P.G. & Research Department of Chemistry, C.P.A. College, Bodinayakanur 625513, Tamilnadu (India); Suganthi, A. [P.G. & Research Department of Chemistry, Thiagarajar College, Madurai 625009, Tamilnadu (India)

    2015-11-30

    Highlights: • Novel FeWO{sub 4}/ZnO nanocomposites synthesized by co-precipitation method. • Nanocomposites were characterized by UV–vis-DRS, FT-IR, XRD, SEM, EDX, TEM and BET techniques. • FeWO{sub 4}/ZnO shows good photocatalytic activity towards degradation of FeWO{sub 4}/ZnO. - Abstract: FeWO{sub 4}/ZnO photocatalyst has been prepared by simple co-precipitation method and characterized using UV–vis diffuse reflectance spectroscopy (UV–vis-DRS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) techniques and Brunauer–Emmett–Teller (BET) techniques. The XRD results showed that the average particle size of ZnO, FeWO{sub 4} and FeWO{sub 4}/ZnO were found to be 31.17 nm, 63.53 nm and 22.59 nm respectively. The prepared photocatalyst composed of rod and plate with little agglomeration is seen from SEM result. The specific surface area of the as prepared FeWO{sub 4}/ZnO photocatalyst was estimated to be 31.3379 m{sup 2}/g. The photocatalyst can degrade methylene blue (MB), an azo dye extensively used in textile and paper industries in water under visible light irradiation. The effect of various parameters such as irradiation time, initial dye concentration, pH and catalyst concentration has been investigated in detail. FeWO{sub 4}/ZnO photocatalyst (0.04 g/L) in the molar ratio of 1:0.5 calcination at 500 °C can effectively degrade about 96% of (20 μm) MB at a pH of about 10 by 180 min illumination in visible light. In all the degradation studies the reaction follows first order kinetics.

  8. Photocatalytic Reduction of Aqueous Cr(VI with CdS under Visible Light Irradiation: Effect of Particle Size

    Directory of Open Access Journals (Sweden)

    A. B. Makama

    2017-04-01

    Full Text Available Stringent environmental standards have made the removal of Cr(VI from water an important problem for environmental scientist and engineering. Heterogeneous photocatalysis using suspended photocatalyst is an interesting technique to consider for this application. In this work, the influence of particle size of suspended CdS on the photocatalytic reduction of aqueous Cr(VI ion was investigated. The efficiency of Cr(VI reduction was monitored through UV-visible analysis. The experimental results showed that the nanoparticle size has a dramatic effect on the adsorption and reduction of Cr(VI. As surface area increased from 44.2±0.6 to 98.7±0.5 m2/g due to particle size reduction, the rate of Cr(VI reduction nearly doubled in the first 20 min of visible light irradiation. The results evidenced the inverse relationship between the apparent reduction rate constant and the CdS particle size. Conversely, the half-life (t1/2 period of the photocatalytic reduction has a direct relationship with CdS particle sizes. Copyright © 2017 BCREC GROUP. All rights reserved Received: 14th July 2016; Revised: 11st October 2016; Accepted: 18th October 2016 How to Cite: Makama, A.B., Salmiaton, A., Saion, E.B., Choong, T.S.Y., Abdullah, N. (2017. Photocatalytic Reduction of Aqueous Cr(VI with CdS under Visible Light Irradiation: Effect of Particle Size. Bulletin of Chemical Reaction Engineering & Catalysis, 12(1: 62-70 (doi:10.9767/bcrec.12.1.593.62-70 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.1.593.62-70

  9. Abscisic acid metabolism and anthocyanin synthesis in grape skin are affected by light emitting diode (LED) irradiation at night.

    Science.gov (United States)

    Kondo, Satoru; Tomiyama, Hiroyuki; Rodyoung, Abhichartbut; Okawa, Katsuya; Ohara, Hitoshi; Sugaya, Sumiko; Terahara, Norihiko; Hirai, Nobuhiro

    2014-06-15

    The effects of blue and red light irradiation at night on abscisic acid (ABA) metabolism and anthocyanin synthesis were examined in grape berries. The expressions of VlMYBA1-2, VlMYBA2, UDP-glucose-flavonoid 3-O-glucosyltransferase (VvUFGT), 9-cis-epoxycarotenoid dioxygenase (VvNCED1), and ABA 8'-hydroxylase (VvCYP707A1) were also investigated. Endogenous ABA, its metabolite phaseic acid (PA), and the expressions of VvNCED1 and VvCYP707A1 were highest in red light-emitting diode (LED)-treated skin. In contrast, anthocyanin concentrations were highest in blue LED-treated skin, followed by red LED treatment. However, the expressions of VlMYBA1-2, VlMYBA2, and VvUFGT did not necessarily coincide with anthocyanin concentrations. The quality of coloring may depend on the amount of malvidin-based anthocyanin, which increased toward harvest in blue and red LED-treated skin, unlike in untreated controls. An increase in sugars was also observed in blue and red LED-treated skin. These results suggest that blue LED irradiation at night may be effective in increasing anthocyanin and sugar concentrations in grape berries. However, there is evidence that another factor may influence anthocyanin concentrations in grape berry skin significantly more than endogenous ABA: ABA concentrations were highest in red LED-treated skin, which had lower anthocyanin concentrations than blue LED-treated skin. Copyright © 2014 Elsevier GmbH. All rights reserved.

  10. Remarkable photo-catalytic degradation of malachite green by nickel doped bismuth selenide under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kulsi, Chiranjit [Department of Physics, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, West Bengal (India); Ghosh, Amrita; Mondal, Anup [Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, West Bengal (India); Kargupta, Kajari [Department of Chemical Engineering, Jadavpur University, Kolkata 700032, West Bengal (India); Ganguly, Saibal [Department of Chemical Engineering, BITS Pilani, K K Birla Goa Campus, NH 17B Bypass Road, Zuarinagar, Sancoale, Goa 403726 (India); Banerjee, Dipali, E-mail: dipalibanerjeebesu@gmail.com [Department of Physics, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, West Bengal (India)

    2017-01-15

    Highlights: • Bi{sub 2}Se{sub 3} and Ni doped Bi{sub 2}Se{sub 3} were synthesized by solvothermal approach. • Presence of nickel was confirmed by X-ray photoelectron spectroscopy (XPS) measurement. • Complete degradation of malachite green (MG) dye was achieved by Ni doped Bi{sub 2}Se{sub 3} with H{sub 2}O{sub 2}. • Remarkable photo-catalytic degradation by doped bismuth selenide has been explained. • Scavenger tests show degradation of MG is mainly dominated by ·OH oxidation process. - Abstract: Bismuth selenide (Bi{sub 2}Se{sub 3}) and nickel (Ni) doped Bi{sub 2}Se{sub 3} were prepared by a solvothermal approach to explore the photo-catalytic performance of the materials in degradation of malachite green (MG). The presence of nickel was confirmed by X-ray photoelectron spectroscopy (XPS) measurement in doped Bi{sub 2}Se{sub 3}. The results showed that the nickel doping played an important role in microstructure and photo-catalytic activity of the samples. Nickel doped Bi{sub 2}Se{sub 3} sample exhibited higher photo-catalytic activity than that of the pure Bi{sub 2}Se{sub 3} sample under visible-light irradiation. The photo-catalytic degradation followed first-order reaction kinetics. Fast degradation kinetics and complete (100% in 5 min of visible light irradiation) removal of MG was achieved by nickel doped Bi{sub 2}Se{sub 3} in presence of hydrogen peroxide (H{sub 2}O{sub 2}) due to modification of band gap energies leading to suppression of photo-generated electron-hole recombination.

  11. Therapeutic effect of turquoise versus blue light with equal irradiance in preterm infants with jaundice

    DEFF Research Database (Denmark)

    Ebbesen, Finn; Madsen, Poul; Støvring, Søren

    2007-01-01

    (OSRAM L18W/860 fluorescent lamps) or blue light (Philips TL20W/52 fluorescent lamps). The concentrations of serum total bilirubin and bilirubin isomers were measured by the Vitros routine method and by HPLC, respectively. RESULTS: The decrease in serum concentrations of total bilirubin, total bilirubin...

  12. Light Irradiation as Key to Shape and Function of Nano-Assemblies in Solution

    Science.gov (United States)

    Groehn, Franziska

    Developing strategies to exploit solar energy become more and more important. Inspired by natural systems it is highly promising to self-assemble functional species into effective tailored supramolecular units. Here we report self-assembled polymer structures in solution, taking advantage of optical properties of hybrid structures and light responsiveness. A new type of photocatalytically active self-assembled polymer structure in aqueous solution consists of supramolecular nano-objects obtained from macroions and multivalent inorganic ``counterions'' such as nanoparticles or clusters. These can exhibit expressed selectivity or even allow catalytic reactions in solution that are not possible with the building blocks only. Further, polyelectrolyte-porphyrin nanoscale assemblies exhibit tunable optical properties including strong fluorescence and an up to 20-fold higher photocatalytic activity than without polymeric template. A different approach is to transfer light energy into mechanical energy. Here, light energy is converted into nanoscale shape changes. This route for the conversion of light is highly promising for applications in drug delivery, nanosensors and solar energy conversion. Membership of DPG, Germany ID 153159-.

  13. The long-term effects of red light-emitting diode irradiation on the proliferation and differentiation of osteoblast-like MC3T3-E1 cells.

    Science.gov (United States)

    Asai, Tomoko; Suzuki, Hiroaki; Kitayama, Midori; Matsumoto, Kousuke; Kimoto, Akira; Shigeoka, Manabu; Komori, Takahide

    2014-06-18

    Low level laser therapy (LLLT) affects various biological processes, and it is said that the non-coherent light of the light-emitting diode (LED) has a similar action. The purpose of this study was to examine the effects of LED light on the proliferation and differentiation of osteoblasts-like MC3T3-E1 cells cultured in osteogenic differentiation medium (ODM) over the long term. Cells were irradiated with red LED light of 630 nm at three doses; 0.5J/cm², 1.5J/cm² or 3.0J/cm² for the cell proliferation activity assay, and at 0.5J/cm² for the osteogenic differentiation activity assay. The former activity was checked by counting the number of viable cells using Trypan blue dye. The latter activity was evaluated by alkaline phosphatase (ALP) staining and examining the mRNA expression of the osteopontin (OPN) gene using real-time quantitative PCR. The number of viable MC3T3-E1 cells showed a tendency to increase after the irradiation at all three energy densities in comparison with a non-irradiation group (control group). In particular, there was a remarkable 3.34-fold increase in the group irradiated with 3.0J/cm² on day 7 after starting the culture. On culture day 15, there was a tendency for the red LED irradiation group (0.5 J/cm²) to exhibit more staining for ALP than the control group, and the expression of OPN was significantly higher in the irradiation group on culture day 16. In conclusion, low level red LED light can enhance MC3T3-E1 cell proliferation and osteogenic differentiation when the cells are cultured for a relatively long time.

  14. The effect of light-emitting diode irradiation at different wavelengths on calcification of osteoblast-like cells in 3D culture.

    Science.gov (United States)

    Chintavalakorn, Rochaya; Tanglitanont, Tatsanee; Khantachawana, Anak; Viravaidya-Pasuwat, Kwanchanok; Santiwong, Peerapong

    2015-08-01

    This study aimed to investigate the effect of four different light-emitting diode (LED) wavelengths on calcification and proliferation of osteoblast-like cells in vitro. MC3T3-E1 cells were seeded within three-dimensional collagen scaffolds and irradiated daily by LED light with peak emission wavelengths of 630-, 680-, 760- and 830-nm at constant fluency of 3.1 J/cm(2) (irradiance intensity 2 mW/cm(2)). Cultures were measured for calcium content at day 0, 7, 14, 21, 28, 35 and 42. The significant enhancement in calcium content was observed at the early stage of culture (days 7 and 14) (plight irradiation on osteoblastic cell calcification. Only 680-nm irradiated samples revealed a significant enhancement of calcium content until the late stages of culture (from days 21 to 42) (p<;0.001). The cyclin D mRNA expression that was investigated 3 hours after stimulation at day3 also show that the 680-nm LED irradiation can enhance cyclin D expression more than others. For enhancing bone mineralization, LED irradiation at the 680-nm is more effective than those at 630-, 760- and 830-nm. Further studies should be investigated in order to obtain the most effective parameters of LLLI on bone regeneration in clinical setting.

  15. Halogens, Barium and Uranium in Mantle Fluid Inclusions

    Science.gov (United States)

    Villa, I. M.; Peverelli, V.; Oglialoro, E.; Pettke, D. T.; Frezzotti, M. L.

    2016-12-01

    Halogens are an underexplored geochemical marker. A way to measure halogens at ng/g levels is measuring Ar, Kr and Xe in irradiated samples [1,2]. We derive absolute halogen amounts from rare gas amounts via scapolite monitor SY [2]. Kr-Xe systematics also yield Ba and U concentrations. We combined irradiation with stepheating on carbonate-sulfate-rich fluid inclusions (FI)-bearing xe­no­liths from El Hierro, Canarias: spinel harzburgite XML-7 and spinel dunite XML-1 [3]. Three components are recognized in the rare gas release. (1) Atmospheric surface contamination occurs up to 1000 °C. (2) FI decrepitation by laboratory heating occurs above 1200 °C [4], corresponding to the release of 80,82Kr and 128Xe in the 1200 and 1400 °C steps. Br whole-rock concentrations are 3-8 ng/g; the molar Br/Cl and I/Cl ratios in the harzburgite FI, 9 E-4 resp. 2 E-4, are identical to those in the dunite FI. This sets the halogens in our FI apart from MORB [2]. Halogen-derived rare gases are closely associated to artificial 131Xe from Ba; Ba has a high affinity of for CO2-rich fluids. Daughter minerals in multiphase FI were identified by Raman micro­spectroscopy [4]. The calculated Ba concentrations are 2-6 µg/g. (3) The third component is U-derived 134,136Xe and 86Kr released in a spike at 1000 °C, decoupled from FI. This requires a different carrier than FI, e.g. Ti oxides. As U concentrations are 10-20 pg/g, the U-bearing phase needs to be below a ppm, invisible by petro­graphy. The 136Xe/134Xe ratio > 1 suggests retention of radio­genic Xe. However, analysis of an unirradiated sample detected no radiogenic Xe. It is likely that Xe-U produced in the core of the McMaster reactor (thermal, epithermal and fast neutrons) has a different isotopic composition from that in textbooks, as proposed by [2].[1] Jeffery & Reynolds (1961) J.Geophys. Res. 66, 3582 [2] Kendrick (2012) Chem. Geol. 292, 116 [3] Oglialoro et al (2015) AGU Fall Meeting abstract V21C-3046 [4] Roedder (1965

  16. Effects of light irradiation upon photodynamic therapy based on 5-aminolevulinic acid-gold nanoparticle conjugates in K562 cells via singlet oxygen generation.

    Science.gov (United States)

    Xu, Hao; Liu, Chen; Mei, Jiansheng; Yao, Cuiping; Wang, Sijia; Wang, Jing; Li, Zheng; Zhang, Zhenxi

    2012-01-01

    As a precursor of the potent photosensitizer protoporphyrin IX (PpIX), 5-aminolevulinic acid (5-ALA), was conjugated onto cationic gold nanoparticles (GNPs) to improve the efficacy of photodynamic therapy (PDT). Cationic GNPs reduced by branched polyethyleneimine and 5-ALA were conjugated onto the cationic GNPs by creating an electrostatic interaction at physiological pH. The efficacy of ALA-GNP conjugates in PDT was investigated under irradiation with a mercury lamp (central wavelength of 395 nm) and three types of light-emitting diode arrays (central wavelengths of 399, 502, and 621 nm, respectively). The impacts of GNPs on PDT were then analyzed by measuring the intracellular PpIX levels in K562 cells and the singlet oxygen yield of PpIX under irradiation. The 2 mM ALA-GNP conjugates showed greater cytotoxicity against K562 cells than ALA alone. Light-emitting diode (505 nm) irradiation of the conjugates caused a level of K562 cell destruction similar to that with irradiation by a mercury lamp, although it had no adverse effects on drug-free control cells. These results may be attributed to the singlet oxygen yield of PpIX, which can be enhanced by GNPs. Under irradiation with a suitable light source, ALA-GNP conjugates can effectively destroy K562 cells. The technique offers a new strategy of PDT.

  17. Effects of light irradiation upon photodynamic therapy based on 5-aminolevulinic acid–gold nanoparticle conjugates in K562 cells via singlet oxygen generation

    Science.gov (United States)

    Xu, Hao; Liu, Chen; Mei, Jiansheng; Yao, Cuiping; Wang, Sijia; Wang, Jing; Li, Zheng; Zhang, Zhenxi

    2012-01-01

    Purpose As a precursor of the potent photosensitizer protoporphyrin IX (PpIX), 5-aminolevulinic acid (5-ALA), was conjugated onto cationic gold nanoparticles (GNPs) to improve the efficacy of photodynamic therapy (PDT). Methods Cationic GNPs reduced by branched polyethyleneimine and 5-ALA were conjugated onto the cationic GNPs by creating an electrostatic interaction at physiological pH. The efficacy of ALA-GNP conjugates in PDT was investigated under irradiation with a mercury lamp (central wavelength of 395 nm) and three types of light-emitting diode arrays (central wavelengths of 399, 502, and 621 nm, respectively). The impacts of GNPs on PDT were then analyzed by measuring the intracellular PpIX levels in K562 cells and the singlet oxygen yield of PpIX under irradiation. Results The 2 mM ALA-GNP conjugates showed greater cytotoxicity against K562 cells than ALA alone. Light-emitting diode (505 nm) irradiation of the conjugates caused a level of K562 cell destruction similar to that with irradiation by a mercury lamp, although it had no adverse effects on drug-free control cells. These results may be attributed to the singlet oxygen yield of PpIX, which can be enhanced by GNPs. Conclusion Under irradiation with a suitable light source, ALA-GNP conjugates can effectively destroy K562 cells. The technique offers a new strategy of PDT. PMID:23055721

  18. Diversified essential properties in halogenated graphenes

    OpenAIRE

    Tran, Ngoc Thanh Thuy; Nguyen, Duy Khanh; E., Glukhova O.; Lin, Ming-Fa

    2017-01-01

    The significant halogenation effects on the essential properties of graphene are investigated by the first-principles method. The geometric structures, electronic properties, and magnetic configurations are greatly diversified under the various halogen adsorptions. Fluorination, with the strong multi-orbital chemical bondings, can create the buckled graphene structure, while the other halogenations do not change the planar {\\sigma} bonding in the presence of single-orbital hybridization. Elec...

  19. All-photonic drying and sintering process via flash white light combined with deep-UV and near-infrared irradiation for highly conductive copper nano-ink.

    Science.gov (United States)

    Hwang, Hyun-Jun; Oh, Kyung-Hwan; Kim, Hak-Sung

    2016-01-25

    We developed an ultra-high speed photonic sintering method involving flash white light (FWL) combined with near infrared (NIR) and deep UV light irradiation to produce highly conductive copper nano-ink film. Flash white light irradiation energy and the power of NIR/deep UV were optimized to obtain high conductivity Cu films. Several microscopic and spectroscopic characterization techniques such as scanning electron microscopy (SEM), a x-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy were employed to characterize the Cu nano-films. Optimally sintered Cu nano-ink films produced using a deep UV-assisted flash white light sintering technique had the lowest resistivity (7.62 μΩ·cm), which was only 4.5-fold higher than that of bulk Cu film (1.68 μΩ•cm).

  20. Self-Strengthening Hybrid Dental Adhesive via Visible-light Irradiation Triple Polymerization

    OpenAIRE

    Song, Linyong; Ye, Qiang.; Ge, Xueping; Misra, Anil; Tamerler, Candan; Spencer, Paulette

    2016-01-01

    A self-strengthening methacrylate-based dental adhesive system was developed by introducing an epoxy cyclohexyl trimethoxysilane (TS) which contains both epoxy and methoxysilyl functional groups. The experimental formulation, HEMA/BisGMA/TS (22.5/27.5/50, wt%), was polymerized by visible-light. Real-time Fourier transform infrared spectroscopy (FTIR) was used to investigate in situ the free radical polymerization of methacrylate, ring-opening cationic polymerization of epoxy, and photoacid-in...

  1. Effects of 630 nm Red and 460 nm Blue Light Emitting Diode Irradiation on Healing of the Skin Wound in Japanese Big-ear White Rabbit.

    Science.gov (United States)

    Li, Yanhong; Zhang, Jigang; Xu, Yanfeng; Han, Yunlin; Jiang, Binbin; Huang, Lan; Zhu, Hua; Xu, Yuhuan; Yang, Weiling; Qin, Chuan

    2017-06-20

    Objective To observe the effects of 630 nm red light and 460 nm blue light emitting diode irradiation on the healing of skin wounds in Japanese big-ear white rabbits. Methods The skin wound model was established with 8 Japanese big-ear white rabbits. Three parts of vulnus in each rabbit were used:two parts of vulnus were irradiated vertically by red and blue LED light,respectively(15 min/time),and the distance between lights and wounds was 15 cm;the 3rd part of the wound was used as a control. On the 21st day of the wounds exposure to light,the number of healing wounds and the percentage of healing area were recorded and the treatment effect of these two light sources was compared. HE staining was used to analyze the newborn tissue structure. Masson staining was used to observe the proliferation of skin collagen fibers. Immuohistochemical staining was used to analyze fibroblast growth factor(FGF),epidermal growth factor(EGF),endothelial growth factor(CD31),proliferating cell nuclear antigen(Ki-67),and inflammatory cytokines(CD68)infiltration in the skin. Results The healing rate in the red light,blue light,and control groups was 50.0%(4/8),25.0%(2/8),and 12.5%(1/8),respectively. Since the 12th day after modeling,the healing area percentage in the red light group was significantly higher than those in the blue light and control groups(Plight group was(2.95±0.34)mm,which was significantly higher than that in control group [(2.52±0.42)mm;F=3.182,P=0.016)]. The average optical density of collagen fibers was 0.15±0.03 in red light group,which was significantly higher than that of the blue light group(0.09±0.01;F=7.316,P=0.012)and control(0.07±0.01;F=7.316,P=0.003). The results of immunohistochemistry showed the expression levels of EGF,FGF,CD31 antigen,and Ki-67 in the red light group were significantly higher than those in the blue light and control groups,whereas the CD68 expression was significantly lower(Plight irradiation can promote the healing of skin wounds

  2. Efficient and stable photocatalytic hydrogen evolution from alkaline formaldehyde solution over Cd0.5Zn0.5S solid solution under visible light irradiation

    Science.gov (United States)

    Peng, Shaoqin; Peng, Huichen; Ding, Min; Li, Yuexiang

    2017-01-01

    Cd0.5Zn0.5S photocatalyst was prepared by a hydrothermal method and characterized by x-ray diffraction and UV-Vis absorption spectroscope techniques. Using the pollutant formaldehyde as an electron donor, the photocatalytic H2 evolution from water splitting under visible light (λ≥420 nm) irradiation was examined. It was found that formaldehyde can notably enhance photocatalytic H2 evolution with its simultaneous degradation. An alkaline condition also was beneficial to the photocatalytic H2 evolution. The effect of formaldehyde concentration on the H2 evolution rate was consistent with a Langmuir-Hinshelwood kinetic model. The stability test indicated that the catalyst was rather stable during 20-h irradiation and the average apparent quantum yield amounted to 3.1% under visible light irradiation (λ≥420 nm) and 25.7% at 420 nm even without any cocatalysts. The possible mechanism was discussed.

  3. Effect of the irradiance distribution from light curing units on the local micro-hardness of the surface of dental resins.

    Science.gov (United States)

    Haenel, Thomas; Hausnerová, Berenika; Steinhaus, Johannes; Price, Richard B T; Sullivan, Braden; Moeginger, Bernhard

    2015-02-01

    An inhomogeneous irradiance distribution from a light-curing unit (LCU) can locally cause inhomogeneous curing with locally inadequately cured and/or over-cured areas causing e.g. monomer elution or internal shrinkage stresses, and thus reduce the lifetime of dental resin based composite (RBC) restorations. The aim of the study is to determine both the irradiance distribution of two light curing units (LCUs) and its influence on the local mechanical properties of a RBC. Specimens of Arabesk TOP OA2 were irradiated for 5, 20, and 80s using a Bluephase® 20i LCU in the Low mode (666mW/cm(2)), in the Turbo mode (2222mW/cm(2)) and a Celalux® 2 (1264mW/cm(2)). The degree of conversion (DC) was determined with an ATR-FTIR. The Knoop micro-hardness (average of five specimens) was measured on the specimen surface after 24h of dark and dry storage at room temperature. The irradiance distribution affected the hardness distribution across the surface of the specimens. The hardness distribution corresponded well to the inhomogeneous irradiance distributions of the LCU. The highest reaction rates occurred after approximately 2s light exposure. A DC of 40% was reached after 3.6 or 5.7s, depending on the LCU. The inhomogeneous hardness distribution was still evident after 80s of light exposure. The irradiance distribution from a LCU is reflected in the hardness distribution across the surface. Irradiance level of the LCU and light exposure time do not affect the pattern of the hardness distribution--only the hardness level. In areas of low irradiation this may result in inadequate resin polymerization, poor physical properties, and hence premature failure of the restorations as they are usually much smaller than the investigated specimens. It has to be stressed that inhomogeneous does not necessarily mean poor if in all areas of the restoration enough light intensity is introduced to achieve a high degree of cure. Copyright © 2014 Academy of Dental Materials. Published by

  4. Graphene–Ag/ZnO nanocomposites as high performance photocatalysts under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, M., E-mail: mzkhm73@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Ahmed, E. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Hong, Z.L., E-mail: hong_zhanglian@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Khalid, N.R. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Ahmed, W.; Elhissi, A. [Institute of Nanotechnology and Bioengineering, University of Central Lancashire, School of Medicine and Dentistry, Preston PR1 2HE (United Kingdom)

    2013-11-15

    Highlights: •Synthesis of Graphene–Ag/ZnO composite photocatalysts by facile one-step nontoxic approach. •Enhanced visible light absorption and efficient charge separation of ZnO by graphene modification and silver doping. •Effective utilization of photo-induced conduction band electron and valance band hole to photocatalytic degradation process. •Excellent photocatalytic performance of composites over pure ZnO. •The reduction in COD and TOC confirms the destruction of the organic molecules in the effluents along with colour removal. -- Abstract: Visible-light-responsive Graphene–Ag/ZnO nanocomposites were fabricated using a facile, one-pot, nontoxic solvothermal process for the photodegradation of organic dyes. During the solvothermal process reduction of graphene oxide and loading of Ag-doped ZnO nanoparticles on two-dimensional graphene sheets were achieved. Electron microscopy, Fourier transform infrared spectroscopy, energy dispersive X-ray analysis, BET surface area measurements, X-ray photoelectron spectroscopy and powder X-ray diffraction were used to confirm that the Ag-doped ZnO nanoparticles as randomly dispersed and effectively decorated on graphene sheets via covalent bonds between Zn and C atoms. Optical properties studied using UV–vis diffuse reflectance spectroscopy confirmed that the absorption edge of Ag-doped ZnO shifted to visible-light region with the incorporation of graphene. The as-synthesized Graphene–Ag/ZnO nanocomposites showed unprecedented photodecomposition efficiency compared to the Ag-doped ZnO, pristine ZnO and commercial ZnO under visible-light. The textile mill effluent containing organic substances was also treated using photocatalysis and the reduction in the chemical oxygen demand (COD) of the treated effluent revealed a complete destruction of the organic molecules along with colour removal. This dramatically enhanced photoactivity of the composite which is attributed to retarded charge recombination rate

  5. Nanostructured composite material graphite/TiO2 and its antibacterial activity under visible light irradiation.

    Science.gov (United States)

    Dědková, Kateřina; Lang, Jaroslav; Matějová, Kateřina; Peikertová, Pavlína; Holešinský, Jan; Vodárek, Vlastimil; Kukutschová, Jana

    2015-08-01

    The paper addresses laboratory preparation, characterization and in vitro evaluation of antibacterial activity of graphite/TiO2 nanocomposites. Composites graphite/TiO2 with various ratio of TiO2 nanoparticles (30wt.%, and 50wt.%) to graphite were prepared using a thermal hydrolysis of titanylsulfate in the presence of graphite particles, and subsequently dried at 80°C. X-ray powder diffraction, transmission electron microscopy and Raman microspectroscopy served as phase-analytical methods distinguishing anatase and rutile phases in the prepared composites. Scanning and transmission electron microscopy techniques were used for characterization of morphology of the prepared samples. A developed modification of the standard microdilution test was used for in vitro evaluation of daylight induced antibacterial activity, using four common human pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa). Antibacterial activity of the graphite/TiO2 nanocomposites could be based mainly on photocatalytic reaction with subsequent potential interaction of reactive oxygen species with bacterial cells. During the antibacterial activity experiments, the graphite/TiO2 nanocomposites exhibited antibacterial activity, where differences in the onset of activity and activity against bacterial strains were observed. The highest antibacterial activity evaluated as minimum inhibitory concentration was observed against P. aeruginosa after 180min of irradiation. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Analysis of the microtensile bond strength to enamel of two adhesive systems polymerized by halogen light or LED Análise da microtração em esmalte de dois sistemas adesivos ativados por LED ou por luz halógena

    Directory of Open Access Journals (Sweden)

    Ana Paula Morales Cobra Carvalho

    2005-12-01

    Full Text Available With the development of composite resin polymerization techniques, LEDs were introduced to the market place. Based on the studied literature, the aim of this study was to evaluate, through microtensile testing, the bond strength to enamel of a composite resin associated to a conventional (multi-bottle adhesive system or to a self etching primer adhesive system, polymerized by halogen light or LED (light emitting diode. Bovine teeth were divided into 4 groups with 10 teeth each (n = 10. Then the adhesives Scotchbond Multipurpose Plus (3M-ESPE and Clearfil SE Bond (Kuraray were applied following the manufacturers’ instructions. Both systems were polymerized for 10 s by halogen light (Degulux Soft Start - Degussa Hulls set at 550 mW/cm² or by LED (Kerr Demetron set at 600 mW/cm². The composite resin Filtek Z-250 was applied in four 1 mm increments with the aid of a square, condensation silicon, 5 mm x 5 mm matrix, and polymerized by either of light sources for 40 s. Scotchbond Multipurpose Plus polymerized by halogen light presented the highest bond strength values (39.69 ± 7.07 MPa, and the other groups did not present statistically significant differences: Scotchbond Multipurpose Plus polymerized by LED (22.28 ± 2.63 MPa, Clearfil SE Bond polymerized by halogen light (27.82 ± 2.65 MPa and by LED (22.89 ± 5.09 MPa.Com a grande busca pelo desenvolvimento das técnicas de polimerização das resinas compostas e dos sistemas adesivos, foram introduzidos no mercado os LEDs. Com base na literatura estudada, neste trabalho é avaliada a força de união da resina composta ao esmalte associado a um sistema adesivo convencional e a um sistema autocondicionante polimerizados por luz halógena e LED, por meio do teste de microtração. Os dentes bovinos foram divididos em 4 grupos com 10 dentes em cada um (n = 10, para aplicação do adesivo Scotchbond Multipurpose Plus (3M-ESPE e do Clearfil SE Bond (Kuraray conforme orientação do fabricante

  7. Efficient visible-light photocatalytic degradation of sulfadiazine sodium with hierarchical Bi₇O₉I₃under solar irradiation.

    Science.gov (United States)

    Xu, MengMeng; Zhao, YaLei; Yan, QiShe

    2015-01-01

    Bi₇O₉I₃, a kind of visible-light-responsive photocatalyst, with hierarchical micro/nano-architecture was successfully synthesized by oil-bath heating method, with ethylene glycol as solvent, and applied to degrade sulfonamide antibiotics. The as-prepared product was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflection spectra and scanning electron microscopy (SEM). XRD and XPS tests confirmed that the product was indeed Bi₇O₉I₃. The result of SEM observation shows that the as-synthesized Bi₇O₉I₃ consists of a large number of micro-sheets with parallel rectangle structure. The optical test exhibited strong photoabsorption in visible light irradiation, with 617 nm of absorption edges. Moreover, the difference in the photocatalytic efficiency of as-prepared Bi₇O₉I₃ at different seasons of a whole year was investigated in this study. The chemical oxygen demand removal efficiency and concentration of NO(3)(-) and SO(4)(2-) of solution after reaction were also researched to confirm whether degradation of the pollutant was complete; the results indicated a high mineralization capacity of Bi₇O₉I₃. The as-synthesized Bi₇O₉I₃exhibits an excellent oxidizing capacity of sulfadiazine sodium and favorable stability during the photocatalytic reaction.

  8. Ultrastructure and Light Microscope Analysis of Intact Skin after a Varying Number of Low Level Laser Irradiations in Mice

    Directory of Open Access Journals (Sweden)

    Mamie Mizusaki Iyomasa

    2014-01-01

    Full Text Available Low level laser therapy (LLLT has been used to relieve pain, inflammation, and wound healing processes. Thus, the skin is overexposed to laser and this effect is not completely understood. This study analyzed the effects of the number of laser applications (three, six, and 10 on the intact skin of the masseteric region in mice of strain HRS/J. The animals (n=30 were equally divided into control (0 J/cm2 and irradiated (20 J/cm2, and each of these groups was further equally divided according to the number of laser applications (three, six, and 10 and underwent LLLT on alternate days. Samples were analyzed by light microscopy and transmission electron microscope (TEM. The animals receiving applications exhibited open channels more dilated between the keratinocytes and photobiomodulation effect on endothelial cells and fibroblasts by TEM. Under the light microscope after 10 laser applications, the type I collagen decreased (P<0.05 compared to the three and six applications. Under these experimental conditions, all numbers of applications provided photobiomodulatory effect on the epidermis and dermis, without damage. More studies are needed to standardize the energy density and number of applications recommended for laser therapy to have a better cost-benefit ratio associated with treatment.

  9. Nanocrystalline TiO2 Composite Films for the Photodegradation of Formaldehyde and Oxytetracycline under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Min Wei

    2017-06-01

    Full Text Available In order to effectively photodegradate organic pollutants, ZnO composite and Co-B codoped TiO2 films were successfully deposited on glass substrates via a modified sol-gel method and a controllable dip-coating technique. Combining with UV–Vis diffuse reflectance spectroscopy (DRS and photoluminescence spectra (PL analyses, the multi-modification could not only extend the optical response of TiO2 to visible light region but also decrease the recombination rate of electron-hole pairs. XRD results revealed that the multi-modified TiO2 film had an anatase-brookite biphase heterostructure. FE-SEM results indicated that the multi-modified TiO2 film without cracks was composed of smaller round-like nanoparticles compared to pure TiO2. BET surface area results showed that the specific surface area of pure TiO2 and the multi-modified TiO2 sample was 47.8 and 115.8 m2/g, respectively. By degradation of formaldehyde and oxytetracycline, experimental results showed that the multi-modified TiO2 film had excellent photodegradation performance under visible light irradiation.

  10. The effect of methyl jasmonate and light irradiation treatments on the stilbenoid biosynthetic pathway in Vitis vinifera cell suspension cultures.

    Science.gov (United States)

    Andi, Seyed Ali; Gholami, Mansour; Ford, Christopher M

    2017-08-29

    Grape stilbenes are a well-known family of plant polyphenolics that have been confirmed to have many biological activities in relation to health benefits. In the present study, we investigated the effect of methyl jasmonate (MeJA) elicitor at four different concentrations (25, 50, 100 and 200 μM) in combination or not with high-level light irradiation (10,000 LUX) on a cell line obtained from the pulp of Vitis vinifera cv. Shahani. Our results showed that the stilbene synthesis pathway is inhibited by high-light conditions. A concentration of 50 μM MeJA was optimum for efficient production and high accumulation of total phenolics and total flavonoids as well as total stilbenoids. Furthermore, we showed that there is a significant negative correlation between the production of these metabolites and cell growth. These data provide valuable information for the future scale-up of cell cultures for the production of these very high value compounds in bioreactor system.

  11. The {0 0 1} facets-dependent superior photocatalytic activities of BiOCl nanosheets under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yingjun [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Wang, Qin, E-mail: qinwang@imu.edu.cn [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Inner Mongolia Key Lab of Nanoscience and Nanotechnology, Inner Mongolia University, Hohhot 010021 (China); Liu, Baocang [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Inner Mongolia Key Lab of Nanoscience and Nanotechnology, Inner Mongolia University, Hohhot 010021 (China); Zhang, Jun, E-mail: cejzhang@imu.edu.cn [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Inner Mongolia Key Lab of Nanoscience and Nanotechnology, Inner Mongolia University, Hohhot 010021 (China)

    2015-09-15

    Graphical abstract: - Highlights: • BiOCl nanosheets were selectively synthesized via a facile hydrothermal method. • The percentage of {0 0 1} facets over BiOCl nanosheets were well controlled. • These samples manifest superior catalytic activity for the degradation of RhB dyes. - Abstract: BiOCl nanosheets with tunable lamella thickness and dominantly exposed {0 0 1} facets were selectively synthesized via a facile hydrothermal method. By modifying the synthetic parameters, such as the amount of P123 and mannitol, the reaction time, types of surfactants, the size, thickness, morphologies, and percentage of {0 0 1} facets over BiOCl nanosheets were well controlled. The exposed {0 0 1} facets with high surface energy and high density of oxygen atoms are not only conducive to the adsorption of the rhodamine B (RhB) dye but also can accumulate the photo-generated electrons, which can be captured by O{sub 2} and converted into reactive oxygen species O{sub 2}{sup −}·. Therefore, the resultant ultrathin BiOCl nanosheets with exposed {0 0 1} facets exhibit superior catalytic activity for dye photosensitization degradation under visible light irradiation. Impressively, the ultrathin BiOCl nanosheets prepared with P123 and mannitol manifest superior catalytic activity and RhB was completely degraded within 20 min. Our current work is expected to offer a new insight into photocatalytic theory for better understanding of visible light photocatalytic reactions and rational design of highly active photocatalysts.

  12. Tandem oxidation/rearrangement of beta-ketoesters to tartronic esters with molecular oxygen catalyzed by calcium iodide under visible light irradiation with fluorescent lamp.

    Science.gov (United States)

    Kanai, Naohiko; Nakayama, Hiroki; Tada, Norihiro; Itoh, Akichika

    2010-05-07

    It was found that beta-ketoesters were directly transformed to the corresponding alpha-hydroxymalonic esters, tartronic esters, with molecular oxygen catalyzed by calcium iodide under visible light irradiation from fluorescent lamp. This reaction includes tandem oxidation/rearrangement and has received much attention from the viewpoint of reduction of energy consumption, labor, and solvents.

  13. WRNIP1 accumulates at laser light irradiated sites rapidly via its ubiquitin-binding zinc finger domain and independently from its ATPase domain

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Hironoshin [Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki Aoba 6-3, Aobaku, Sendai 980-8578 (Japan); Yoshimura, Akari, E-mail: akari_yo@musashino-u.ac.jp [Research Institute of Pharmaceutical Sciences, Faculty of Pharmacy, Musashino University, 1-1-20 Shinmachi, Nishitokyo-shi, Tokyo 202-8585 (Japan); Edo, Takato [Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki Aoba 6-3, Aobaku, Sendai 980-8578 (Japan); Kanno, Shin-ichiro [Division of Dynamic Proteome, Institute of Development, Aging and Cancer, Tohoku University, Seiryomachi 4-1, Aobaku, Sendai 980-8575 (Japan); Tada, Syusuke [Faculty of Pharmaceutical Sciences, Teikyo Heisei University, Ichihara, Chiba 290-0193 (Japan); Seki, Masayuki [Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki Aoba 6-3, Aobaku, Sendai 980-8578 (Japan); Yasui, Akira [Division of Dynamic Proteome, Institute of Development, Aging and Cancer, Tohoku University, Seiryomachi 4-1, Aobaku, Sendai 980-8575 (Japan); Enomoto, Takemi [Research Institute of Pharmaceutical Sciences, Faculty of Pharmacy, Musashino University, 1-1-20 Shinmachi, Nishitokyo-shi, Tokyo 202-8585 (Japan)

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer WRNIP1 accumulates in laser light irradiated sites very rapidly via UBZ domain. Black-Right-Pointing-Pointer The ATPase domain of WRNIP1 is dispensable for its accumulation. Black-Right-Pointing-Pointer The accumulation of WRNIP1 seems not to be dependent on the interaction with WRN. -- Abstract: WRNIP1 (Werner helicase-interacting protein 1) was originally identified as a protein that interacts with the Werner syndrome responsible gene product. WRNIP1 contains a ubiquitin-binding zinc-finger (UBZ) domain in the N-terminal region and two leucine zipper motifs in the C-terminal region. In addition, it possesses an ATPase domain in the middle of the molecule and the lysine residues serving as ubiquitin acceptors in the entire of the molecule. Here, we report that WRNIP1 accumulates in laser light irradiated sites very rapidly via its ubiquitin-binding zinc finger domain, which is known to bind polyubiquitin and to be involved in ubiquitination of WRNIP1 itself. The accumulation of WRNIP1 in laser light irradiated sites also required the C-terminal region containing two leucine zippers, which is reportedly involved in the oligomerization of WRNIP1. Mutated WRNIP1 with a deleted ATPase domain or with mutations in lysine residues, which serve as ubiquitin acceptors, accumulated in laser light irradiated sites, suggesting that the ATPase domain of WRNIP1 and ubiquitination of WRNIP1 are dispensable for the accumulation.

  14. Comparative study on toxicity of ZnO and TiO2 nanoparticles on Artemia salina: effect of pre-UV-A and visible light irradiation.

    Science.gov (United States)

    Bhuvaneshwari, M; Sagar, Bhawana; Doshi, Siddharth; Chandrasekaran, N; Mukherjee, Amitava

    2017-02-01

    This study evaluated the toxicity potential of ZnO and TiO2 nanoparticles under pre-UV-A irradiation and visible light condition on Artemia salina. The nanoparticle suspension was prepared in seawater medium and exposed under pre-UV-A (0.23 mW/cm2) and visible light (0.18 mW/cm2) conditions. The aggregation profiles of both nanoparticles (NPs) and dissolution of ZnO NPs under both irradiation conditions at various kinetic intervals (1, 24, 48 h) were studied. The 48-h LC50 values were found to be 27.62 and 71.63 mg/L for ZnO NPs and 117 and 120.9 mg/L for TiO2 NPs under pre-UV-A and visible light conditions. ZnO NPs were found to be more toxic to A. salina as compared to TiO2 NPs. The enhanced toxicity was observed under pre-UV-A-irradiated ZnO NPs, signifying its phototoxicity. Accumulation of ZnO and TiO2 NPs into A. salina depends on the concentration of particles and type irradiations. Elimination of accumulated nanoparticles was also evident under both irradiation conditions. Other than ZnO NPs, the dissolved Zn2+ also had a significant effect on toxicity and accumulation in A. salina. Increased catalase (CAT) activity in A. salina indicates the generation of oxidative stress due to NP interaction. Thus, this study provides an understanding of the toxicity of photoreactive ZnO and TiO2 NPs as related to the effects of pre-UV-A and visible light irradiation.

  15. Effects of Blue Light Emitting Diode Irradiation On the Proliferation, Apoptosis and Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Ye Yuan

    2017-08-01

    Full Text Available Background/Aims: Blue light emitting diodes (LEDs have been proven to affect the growth of several types of cells. The effects of blue LEDs have not been tested on bone marrow-derived mesenchymal stem cells (BMSCs, which are important for cell-based therapy in various medical fields. Therefore, the aim of this study was to determine the effects of blue LED on the proliferation, apoptosis and osteogenic differentiation of BMSCs. Methods: BMSCs were irradiated with a blue LED light at 470 nm for 1 min, 5 min, 10 min, 30 min and 60 min or not irradiated. Cell proliferation was measured by performing cell counting and EdU staining assays. Cell apoptosis was detected by TUNEL staining. Osteogenic differentiation was evaluated by ALP and ARS staining. DCFH-DA staining and γ-H2A.X immunostaining were used to measure intracellular levels of ROS production and DNA damage. Results: Both cell counting and EdU staining assays showed that cell proliferation of BMSCs was significantly reduced upon blue LED irradiation. Furthermore, treatment of BMSCs with LED irradiation was followed by a remarkable increase in apoptosis, indicating that blue LED light induced toxic effects on BMSCs. Likewise, BMSC osteogenic differentiation was inhibited after exposure to blue LED irradiation. Further, blue LED irradiation was followed by the accumulation of ROS production and DNA damage. Conclusions: Taken together, our study demonstrated that blue LED light inhibited cell proliferation, inhibited osteogenic differentiation, and induced apoptosis in BMSCs, which are associated with increased ROS production and DNA damage. These findings may provide important insights for the application of LEDs in future BMSC-based therapies.

  16. Effects of Blue Light Emitting Diode Irradiation On the Proliferation, Apoptosis and Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells.

    Science.gov (United States)

    Yuan, Ye; Yan, Gege; Gong, Rui; Zhang, Lai; Liu, Tianyi; Feng, Chao; Du, Weijie; Wang, Ying; Yang, Fan; Li, Yuan; Guo, Shuyuan; Ding, Fengzhi; Ma, Wenya; Idiiatullina, Elina; Pavlov, Valentin; Han, Zhenbo; Cai, Benzhi; Yang, Lei

    2017-01-01

    Blue light emitting diodes (LEDs) have been proven to affect the growth of several types of cells. The effects of blue LEDs have not been tested on bone marrow-derived mesenchymal stem cells (BMSCs), which are important for cell-based therapy in various medical fields. Therefore, the aim of this study was to determine the effects of blue LED on the proliferation, apoptosis and osteogenic differentiation of BMSCs. BMSCs were irradiated with a blue LED light at 470 nm for 1 min, 5 min, 10 min, 30 min and 60 min or not irradiated. Cell proliferation was measured by performing cell counting and EdU staining assays. Cell apoptosis was detected by TUNEL staining. Osteogenic differentiation was evaluated by ALP and ARS staining. DCFH-DA staining and γ-H2A.X immunostaining were used to measure intracellular levels of ROS production and DNA damage. Both cell counting and EdU staining assays showed that cell proliferation of BMSCs was significantly reduced upon blue LED irradiation. Furthermore, treatment of BMSCs with LED irradiation was followed by a remarkable increase in apoptosis, indicating that blue LED light induced toxic effects on BMSCs. Likewise, BMSC osteogenic differentiation was inhibited after exposure to blue LED irradiation. Further, blue LED irradiation was followed by the accumulation of ROS production and DNA damage. Taken together, our study demonstrated that blue LED light inhibited cell proliferation, inhibited osteogenic differentiation, and induced apoptosis in BMSCs, which are associated with increased ROS production and DNA damage. These findings may provide important insights for the application of LEDs in future BMSC-based therapies. © 2017 The Author(s). Published by S. Karger AG, Basel.

  17. Cryptochrome and phytochrome cooperatively but independently reduce active gibberellin content in rice seedlings under light irradiation.

    Science.gov (United States)

    Hirose, Fumiaki; Inagaki, Noritoshi; Hanada, Atsushi; Yamaguchi, Shinjiro; Kamiya, Yuji; Miyao, Akio; Hirochika, Hirohiko; Takano, Makoto

    2012-09-01

    In contrast to a wealth of knowledge about the photoregulation of gibberellin metabolism in dicots, that in monocots remains largely unclear. In this study, we found that a blue light signal triggers reduction of active gibberellin content in rice seedlings with simultaneous repression of two gibberellin 20-oxidase genes (OsGA20ox2 and OsGA20ox4) and acute induction of four gibberellin 2-oxidase genes (OsGA2ox4-OsGA2ox7). For further examination of the regulation of these genes, we established a series of cryptochrome-deficient lines through reverse genetic screening from a Tos17 mutant population and construction of knockdown lines based on an RNA interference technique. By using these lines and phytochrome mutants, we elucidated that cryptochrome 1 (cry1), consisting of two species in rice plants (cry1a and cry1b), is indispensable for robust induction of the GA2ox genes. On the other hand, repression of the GA20ox genes is mediated by phytochromes. In addition, we found that the phytochromes also mediate the repression of a gibberellin 3-oxidase gene (OsGA3ox2) in the light. These results imply that, in rice seedlings, phytochromes mediate the repression of gibberellin biosynthesis capacity, while cry1 mediates the induction of gibberellin inactivation capacity. The cry1 action was demonstrated to be dominant in the reduction of active gibberellin content, but, in rice seedlings, the cumulative effects of these independent actions reduced active gibberellin content in the light. This pathway design in which different types of photoreceptors independently but cooperatively regulate active gibberellin content is unique from the viewpoint of dicot research. This redundancy should provide robustness to the response in rice plants.

  18. Light yield measurements of “finger” structured and unstructured scintillators after gamma and neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Afanasiev, S.V. [Joint Institute for Nuclear Research (JINR), Dubna (Russian Federation); Boyarintsev, A.Yu. [Institute for Scintillation Materials, National Academy of Sciences of Ukraine (ISMA), Kharkov (Ukraine); Danilov, M.V. [National Research Nuclear University “MEPhI”, Moscow (Russian Federation); Emeliantchik, I.F. [National Center for Particle and High Energy Physics (NCPHEP), Minsk (Belarus); Ershov, Yu.V.; Golutvin, I.A. [Joint Institute for Nuclear Research (JINR), Dubna (Russian Federation); Grinyov, B.V. [Institute for Scintillation Materials, National Academy of Sciences of Ukraine (ISMA), Kharkov (Ukraine); Ibragimova, E. [Institute of Nuclear Physics (INP), Tashkent (Uzbekistan); Levchuk, L.G. [National Scientific Center, Kharkov Institute of Physics and Technology (KIPT), Kharkov (Ukraine); Litomin, A.V. [National Center for Particle and High Energy Physics (NCPHEP), Minsk (Belarus); Makankin, A.M.; Malakhov, A.I.; Moisenz, P.V. [Joint Institute for Nuclear Research (JINR), Dubna (Russian Federation); Nuritdinov, I. [Institute of Nuclear Physics (INP), Tashkent (Uzbekistan); Popov, V.F. [National Scientific Center, Kharkov Institute of Physics and Technology (KIPT), Kharkov (Ukraine); Rusinov, V.Yu. [National Research Nuclear University “MEPhI”, Moscow (Russian Federation); Shumeiko, N.M. [National Center for Particle and High Energy Physics (NCPHEP), Minsk (Belarus); Smirnov, V.A., E-mail: vitsmirnov@jinr.ru [Joint Institute for Nuclear Research (JINR), Dubna (Russian Federation); Sorokin, P.V. [National Scientific Center, Kharkov Institute of Physics and Technology (KIPT), Kharkov (Ukraine); Tarkovskii, E.I. [National Research Nuclear University “MEPhI”, Moscow (Russian Federation); and others

    2016-05-11

    Plastic scintillators are often used as detectors in High Energy Physics (HEP), but have insufficient radiation hardness. Organization of better light collection inside a single detector may prolong operation life of scintillators. A finger-strip plastic scintillator option has many advantages to keep the excellent detector performance at high luminosity. Measurements assigned to show an advantage of a stripped detector vs. the un-stripped one in the range of increased absorbed doses and the smallest dose rates have been performed. This method has proved to be a good upgrade strategy.

  19. Secondary neutron production from thick Pb target by light particle irradiation

    CERN Document Server

    Adloff, J C; Debeauvais, M; Fernández, F; Krivopustov, M; Kulakov, B A; Sosnin, A; Zamani, M

    1999-01-01

    Neutron multiplicities from spallation neutron sources were measured by Solid State Nuclear Track Detectors. Light particles as protons, deuterons and alphas in the GeV range were used on Pb targets. For neutron thermalization the targets were covered by 6 cm paraffin moderator. Neutron multiplicity distributions were studied inside and on the moderator surface. Comparison of SSNTDs results were made for thermal-epithermal neutrons with sup 1 sup 3 sup 9 La activation method as well as with Dubna DCM/CEM code. Discussion including previous sup 1 sup 2 C results are given.

  20. Session 4: Solid solution sulfide photo-catalysts for hydrogen evolution under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, I.; Kato, H. [Tokyo Univ., Faculty of Science, Dept. of Applied Chemistry (Japan); Kudo, A.; Kobayashi, H. [Kurashiki Univ. of Science and the Arts, (Japan); Kudo, A. [Japan Science and Technology Agency, Core Research for Evolutional Science and Technology (Japan)

    2004-07-01

    In the present study, we tried to make a new visible-light driven photo-catalyst for H{sub 2} evolution by making solid solutions between ZnS photo-catalyst with a wide band gap, and AgInS{sub 2} and CuInS{sub 2} with narrow band gaps. The photophysical and photo-catalytic properties of (MIn){sub x}Zn{sub 2(1-x)}S{sub 2} (M=Cu, Ag) solid solutions were investigated. (authors)

  1. Artificial Neural Network Modelling of Photodegradation in Suspension of Manganese Doped Zinc Oxide Nanoparticles under Visible-Light Irradiation

    Directory of Open Access Journals (Sweden)

    Yadollah Abdollahi

    2014-01-01

    Full Text Available The artificial neural network (ANN modeling of m-cresol photodegradation was carried out for determination of the optimum and importance values of the effective variables to achieve the maximum efficiency. The photodegradation was carried out in the suspension of synthesized manganese doped ZnO nanoparticles under visible-light irradiation. The input considered effective variables of the photodegradation were irradiation time, pH, photocatalyst amount, and concentration of m-cresol while the efficiency was the only response as output. The performed experiments were designed into three data sets such as training, testing, and validation that were randomly splitted by the software’s option. To obtain the optimum topologies, ANN was trained by quick propagation (QP, Incremental Back Propagation (IBP, Batch Back Propagation (BBP, and Levenberg-Marquardt (LM algorithms for testing data set. The topologies were determined by the indicator of minimized root mean squared error (RMSE for each algorithm. According to the indicator, the QP-4-8-1, IBP-4-15-1, BBP-4-6-1, and LM-4-10-1 were selected as the optimized topologies. Among the topologies, QP-4-8-1 has presented the minimum RMSE and absolute average deviation as well as maximum R-squared. Therefore, QP-4-8-1 was selected as final model for validation test and navigation of the process. The model was used for determination of the optimum values of the effective variables by a few three-dimensional plots. The optimum points of the variables were confirmed by further validated experiments. Moreover, the model predicted the relative importance of the variables which showed none of them was neglectable in this work.

  2. Fenton Process Coupled to Ultrasound and UV Light Irradiation for the Oxidation of a Model Pollutant

    Directory of Open Access Journals (Sweden)

    Karen E. Barrera-Salgado

    2016-01-01

    Full Text Available The Fenton process coupled to photosonolysis (UV light and Us, using Fe2O3 catalyst supported on Al2O3, was used to oxidize a model pollutant like acid green 50 textile dye (AG50. Dye degradation was followed by AG50 concentration decay analyses. It was observed that parameters like iron content on a fixed amount of catalyst supporting material, catalyst annealing temperature, initial dye concentration, and the solution pH influence the overall treatment efficiency. High removal efficiencies of the model pollutant are achieved. The stability and reusability tests of the Fe2O3 catalyst show that the catalyst can be used up to three cycles achieving high discoloration. Thus, this catalyst is highly efficient for the degradation of AG50 in the Fenton process.

  3. APPLICATION OF LIGHT EMITTING DIODE IRRADIATION IN SURGERY AND OTHER FIELDS OF MEDICINE

    Directory of Open Access Journals (Sweden)

    Iskander Mukhamedovich Baybekov

    2017-05-01

    Full Text Available Goal. To study the experience of using Light Emitting Diode (LED in surgery and other areas of medicine. Methods and methodology. The methodological basis is the analysis of literature, synthesis of the results of experimental and clinical studies, as well as a modern interpretation of the mechanisms of action of low-intensity laser radiation and LED effects on the body. Special attention is paid to the experience of clinical and morphological studies LED of impacts at the Republican specialized center of surgery named academician V. Vahidov of the Ministry of health of the Republic of Uzbekistan. Results. Comparative features of LED and lasers, such as stimulation of reparative processes, their influence on healing of skin wounds and sternum after sternotomy, red blood cells and microcirculation are discussed. Conclusion. It has been suggested that LED is a worthy alternative to lasers. Their use is advisable in complex treatment of surgical diseases.

  4. Starch mediated CdS nanoparticles and their photocatalytic performance under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Firdaus, Farha, E-mail: Farha-firdaus@yahoo.co.in [Chemistry Section, Women’s College, Aligarh Muslim University, Aligarh 202002 UP (India); Faraz, Mohd [Department of Chemistry, Faculty of Science, Aligarh Muslim University, Aligarh 202002 (India)

    2016-05-06

    Green synthesis of Cadmium Sulphide (CdS-S) nanoparticles is of considerable interest due to its biocompatible and nontoxicity. Here, we present a biomolecule stimulated chemical method was adopted for the successful synthesis of CdS-S nanoparticles using starch as a capping agent. The CdS-S nanoparticles were characterized by various analytical techniques. The CdS-S nanoparicles exhibit photocatalytic activity against methyl orange (MO) at pH 9 in Visible light and the reaction follows pseudo first-order kinetics. The comparative photocatalytic activity revealed that CdS-S nanoparticles remarkably enhanced activities as compared to the commercial TiO{sub 2} nanoparticles. The outcome of these studies offers valuable for planning CdS-S nanoparticles having photocatalytic activities helpful for the formulation of waste water remediation.

  5. Biological synthesis of very small silver nanoparticles by culture supernatant of Klebsiella pneumonia: The effects of visible-light irradiation and the liquid mixing process

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari, Narges [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Daneshpajouh, Shahram; Seyedbagheri, Seyedali; Atashdehghan, Reza [Hydrometallurgy Research Unit, Research and Development Center, National Iranian Copper Industries Company, Sarcheshmeh, Rafsanjan (Iran, Islamic Republic of); Abdi, Khosro [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sarkar, Saeed [Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Minaian, Sara [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shahverdi, Hamid Reza [Department of Material Science, Faculty of Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza, E-mail: shahverd@sina.tums.ac.ir [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2009-06-03

    This study has investigated different visible-light irradiation's effect on the formation of silver nanoparticles from silver nitrate using the culture supernatant of Klebsiella pneumonia. Our study shows that visible-light emission can significantly prompt the synthesis of silver nanoparticles. Also, the study experimentally investigated the liquid mixing process effect on silver nanoparticle synthesis by visible-light irradiation. This study successfully synthesized uniformly dispersed silver nanoparticles with a uniform size and shape in the range of 1-6 nm with an average size of 3 nm. Furthermore, the study investigated the mechanism of the reduction of silver ions by culture supernatant of K. pneumonia, and used X-ray diffraction to characterize silver chloride as an intermediate compound. Silver chloride was prepared synthetically and used as a substrate for the synthesis of silver nanoparticles by culture supernatant of K. pneumonia. The silver nanoparticles have been prepared from silver chloride during this investigation for the first time.

  6. Enhanced photocatalytic performance of (ZnO/CeO2)-β-CD system for the effective decolorization of Rhodamine B under UV light irradiation

    Science.gov (United States)

    Velusamy, Ponnusamy; Lakshmi, Gurunathan

    2017-11-01

    In this work, we attempt a new approach for the study on photocatalytic ability of (ZnO/CeO2 ) improved by β-CD under UV light irradiation for the photodecolorization of RhB. The (ZnO/CeO2 ) composite was prepared by mixing ZnO with CeO2 in a weight ratio of 4:1. The surface interaction of (ZnO/CeO2 ) with β-CD was determined by characterizing their structural, morphological and optical properties. The formation of an inclusion complex between RhB dye and β-CD was confirmed by UV-visible spectral analyses. The photocatalytic activity of (ZnO/CeO2 )-β-CD system was evaluated by the decolorization of RhB dye in aqueous solution under UV light irradiation. The effects of operational parameters like the ratio of (ZnO/CeO2), initial concentration of dye, catalyst dose, irradiation time and pH have been analyzed. The photocatalytic decolorization of RhB follows pseudo-first order kinetics. The mineralization of RhB has been confirmed by COD measurements. A possible mechanism for the photocatalytic decolorization of RhB by (ZnO/CeO2 )-β-CD system under UV light irradiation was also discussed.

  7. Thermoluminescence in alkali halides irradiated at 80K; Termoluminiscencia en haluros alcalinos irradiados a 80K

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez de Castro, M.

    1978-07-01

    The thermoluminescence, the thermally stimulated currents and the thermal stability of the F centres induced in pure NaCl and KC1 crystals by X irradiation at 80K have been studied in detail, In the range between 80 and 300K. The thermoluminescent processes induced by illumination at 80K with F light in samples previously irradiated at room temperature has also been studied. It has been clearly observed the existence of thermoluminescent processes due to electrons and holes thermally released from traps, in which the F centres are not involved. The existence of hole-F centre recombination has not been observed. There are several thermoluminescent processes in both materials which are scribed to the recombination of F centres with mobile interstitial halogen atoms thermally released from traps, which are likely monovalent impurities in this temperature interval. The light emitting stage in these processes is originated by the formation of self trapped excitons. (Author) 66 refs.

  8. Energy efficiency for the removal of non-polar pollutants during ultraviolet irradiation, visible light photocatalysis and ozonation of a wastewater effluent.

    Science.gov (United States)

    Santiago-Morales, Javier; Gómez, María José; Herrera-López, Sonia; Fernández-Alba, Amadeo R; García-Calvo, Eloy; Rosal, Roberto

    2013-10-01

    This study aims to assess the removal of a set of non-polar pollutants in biologically treated wastewater using ozonation, ultraviolet (UV 254 nm low pressure mercury lamp) and visible light (Xe-arc lamp) irradiation as well as visible light photocatalysis using Ce-doped TiO2. The compounds tracked include UV filters, synthetic musks, herbicides, insecticides, antiseptics and polyaromatic hydrocarbons. Raw wastewater and treated samples were analyzed using stir-bar sorptive extraction coupled with comprehensive two-dimensional gas chromatography (SBSE-CG × GC-TOF-MS). Ozone treatment could remove most pollutants with a global efficiency of over 95% for 209 μM ozone dosage. UV irradiation reduced the total concentration of the sixteen pollutants tested by an average of 63% with high removal of the sunscreen 2-ethylhexyl trans-4-methoxycinnamate (EHMC), the synthetic musk 7-acetyl-1,1,3,4,4,6-hexamethyltetrahydronaphthalene (tonalide, AHTN) and several herbicides. Visible light Ce-TiO2 photocatalysis reached ~70% overall removal with particularly high efficiency for synthetic musks. In terms of power usage efficiency expressed as nmol kJ(-1), the results showed that ozonation was by far the most efficient process, ten-fold over Xe/Ce-TiO2 visible light photocatalysis, the latter being in turn considerably more efficient than UV irradiation. In all cases the efficiency decreased along the treatments due to the lower reaction rate at lower pollutant concentration. The use of photocatalysis greatly improved the efficiency of visible light irradiation. The collector area per order decreased from 9.14 ± 5.11 m(2) m(-3) order(-1) for visible light irradiation to 0.16 ± 0.03 m(2) m(-3) order(-1) for Ce-TiO2 photocatalysis. The toxicity of treated wastewater was assessed using the green alga Pseudokirchneriella subcapitata. Ozonation reduced the toxicity of treated wastewater, while UV irradiation and visible light photocatalysis limited by 20-25% the algal growth due to

  9. xBiOI-(1 - x)BiOCl as efficient visible-light-driven photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wang Wendeng [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Huang Fuqiang [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)], E-mail: huangfq@mail.sic.ac.cn; Lin Xinping [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

    2007-04-15

    A new class of oxyhalide photocatalysts, xBiOI-(1 - x)BiOCl, were prepared by a soft chemical method. The samples with x = 0.2-1.0 have intense absorptions in the visible light region and the optical band gaps are in the range 1.92-2.31 eV. They possess high photocatalytic activities under visible light irradiation for the degradation of methyl orange. This high photocatalytic activity is in close relation with the deep valance band edge position and the internal electric fields between [Bi{sub 2}O{sub 2}] slabs and halogen anionic slabs.

  10. Enhanced photocatalytic activity of Bi2WO6/TiO2 composite coated polyester fabric under visible light irradiation

    Science.gov (United States)

    Du, Zoufei; Cheng, Cheng; Tan, Lin; Lan, Jianwu; Jiang, Shouxiang; Zhao, Ludan; Guo, Ronghui

    2018-03-01

    In this study, a visible-light-driven photocatalyst Bi2WO6/TiO2 composite was reported using one-step hydrothermal method and then coated on the polyester fabric. The samples were systematically characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, UV-vis diffuse reflection spectroscopy and photoluminescence spectroscopy (PL). The photocatalytic activity of Bi2WO6/TiO2 coated polyester fabric was evaluated by degradation of Rhodamine B (RhB) and Methylene blue (MB) under visible light irradiation. The self-cleaning property of the fabrics was assessed through removing red wine stain. The results reveal that the Bi2WO6/TiO2 composites with irregular shape are coated on the polyester fabric successfully. The UV-vis absorption spectra show a broad absorption band in the visible region, which extends the scope of absorption spectrum and helps to improve the photocatalytic degradation efficiency. Photocatalytic activities of the Bi2WO6/TiO2 composite polyester fabric are associated with the content of TiO2. Bi2WO6/15%TiO2 coated polyester fabric exhibits the degradation efficiency for RhB and MB up to 98% and 95.1%, respectively, which is much higher than that of pure Bi2WO6 and TiO2 coated polyester fabric. Moreover, Bi2WO6/15%TiO2 coated polyester fabric shows good cycle stability toward continuous three cycles of photocatalytic experiment for dyes degradation. In addition, the Bi2WO6/TiO2 coated polyester fabric shows good self-cleaning property. This work could be extended to design of other composite photocatalyst coating on the fabric for enhancing activity by coupling suitable wide and narrow band-gap semiconductors.

  11. Organic matters removal from landfill leachate by immobilized Phanerochaete chrysosporium loaded with graphitic carbon nitride under visible light irradiation.

    Science.gov (United States)

    Hu, Liang; Liu, Yutang; Zeng, Guangming; Chen, Guiqiu; Wan, Jia; Zeng, Yunxiong; Wang, Longlu; Wu, Haipeng; Xu, Piao; Zhang, Chen; Cheng, Min; Hu, Tianjue

    2017-10-01

    This study investigated the technical applicability of a combination of Phanerochaete chrysosporium (P. chrysosporium) with photocatalyst graphitic carbon nitride (g-C3N4) for organic matters removal from landfill leachate under visible light irradiation. Photocatalyst g-C3N4 was well immobilized on the hyphae surface of P. chrysosporium by calcium alginate. The typical absorption edge in visible light region for g-C3N4 was at about 460 nm, and the optical absorption bandgap of g-C3N4 was estimated to be 2.70 eV, demonstrating the great photoresponsive ability of g-C3N4. An optimized g-C3N4 content of 0.10 g in immobilized P. chrysosporium and an optimized immobilized P. chrysosporium dosage of 1.0 g were suitable for organic matters removal. The removal efficiency of total organic carbon (TOC) reached 74.99% in 72 h with the initial TOC concentration of 100 mg L-1. In addition, the gas chromatography coupled with mass spectrometry (GC-MS) measurements showed that immobilized P. chrysosporium presented an outstanding removal performance for almost all organic compounds in landfill leachate, especially for the volatile fatty acids and long-chain hydrocarbons. The overall results indicate that the combination P. chrysosporium with photocatalyst g-C3N4 for organic matters removal from landfill leachate may provide a more comprehensive potential for the landfill leachate treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Effects of blue pulsed light on human physiological functions and subjective evaluation

    Directory of Open Access Journals (Sweden)

    Katsuura Tetsuo

    2012-09-01

    Full Text Available Abstract Background It has been assumed that light with a higher irradiance of pulsed blue light has a much greater influence than that of light with a lower irradiance of steady blue light, although they have the same multiplication value of irradiance and duration. We examined the non-visual physiological effects of blue pulsed light, and determined whether it is sensed visually as being blue. Findings Seven young male volunteers participated in the study. We placed a circular screen (diameter 500 mm in front of the participants and irradiated it using blue and/or white light-emitting diodes (LEDs, and we used halogen lamps as a standard illuminant. We applied three steady light conditions of white LED (F0, blue LED + white LED (F10, and blue LED (F100, and a blue pulsed light condition of a 100-μs pulse width with a 10% duty ratio (P10. The irradiance of all four conditions at the participant's eye level was almost the same, at around 12 μW/cm2. We measured their pupil diameter, recorded electroencephalogram readings and Kwansei Gakuin Sleepiness Scale score, and collected subjective evaluations. The subjective bluish score under the F100 condition was significantly higher than those under other conditions. Even under the P10 condition with a 10% duty ratio of blue pulsed light and the F10 condition, the participant did not perceive the light as bluish. Pupillary light response under the P10 pulsed light condition was significantly greater than under the F10 condition, even though the two conditions had equal blue light components. Conclusions The pupil constricted under the blue pulsed light condition, indicating a non-visual effect of the lighting, even though the participants did not perceive the light as bluish.

  13. Effects of blue pulsed light on human physiological functions and subjective evaluation.

    Science.gov (United States)

    Katsuura, Tetsuo; Ochiai, Yukifumi; Senoo, Toshihiro; Lee, Soomin; Takahashi, Yoshika; Shimomura, Yoshihiro

    2012-09-03

    It has been assumed that light with a higher irradiance of pulsed blue light has a much greater influence than that of light with a lower irradiance of steady blue light, although they have the same multiplication value of irradiance and duration. We examined the non-visual physiological effects of blue pulsed light, and determined whether it is sensed visually as being blue. Seven young male volunteers participated in the study. We placed a circular screen (diameter 500 mm) in front of the participants and irradiated it using blue and/or white light-emitting diodes (LEDs), and we used halogen lamps as a standard illuminant. We applied three steady light conditions of white LED (F0), blue LED + white LED (F10), and blue LED (F100), and a blue pulsed light condition of a 100-μs pulse width with a 10% duty ratio (P10). The irradiance of all four conditions at the participant's eye level was almost the same, at around 12 μW/cm2. We measured their pupil diameter, recorded electroencephalogram readings and Kwansei Gakuin Sleepiness Scale score, and collected subjective evaluations. The subjective bluish score under the F100 condition was significantly higher than those under other conditions. Even under the P10 condition with a 10% duty ratio of blue pulsed light and the F10 condition, the participant did not perceive the light as bluish. Pupillary light response under the P10 pulsed light condition was significantly greater than under the F10 condition, even though the two conditions had equal blue light components. The pupil constricted under the blue pulsed light condition, indicating a non-visual effect of the lighting, even though the participants did not perceive the light as bluish.

  14. Photodegradation of 4-alkylphenols using BiVO{sub 4} photocatalyst under irradiation with visible light from a solar simulator

    Energy Technology Data Exchange (ETDEWEB)

    Kohtani, Shigeru; Tokumura, Kunihiro; Ishigaki, Yasuhito; Hayakawa, Kazuichi; Nakagaki, Ryoichi [Graduate School of Natural Science and Technology, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934 (Japan); Koshiko, Masaya; Toriba, Akira [Faculty of Pharmaceutical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934 (Japan); Kudo, Akihiko [Department of Applied Chemistry, Faculty of Science, Science University of Tokyo, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

    2003-11-28

    A visible-light-driven photocatalyst, BiVO{sub 4}, has been applied for degradation of a series of linear 4-n-alkylphenols under irradiation from a solar simulator. Degradation rates become faster with increasing alkyl chain length. Half-life of 4-n-nonylphenol (4-n-NP) is 18min, which is about eight times shorter than that of phenol. The rate law of disappearance for heptyl-, octyl- and nonylphenols exhibits zero-order kinetics. The amount of adsorption on BiVO{sub 4} surface is much larger for longer hydrophobic alkylphenols. It is thus concluded that BiVO{sub 4} is suitable for degradation of hydrophobic alkylphenols such as nonyl- and octylphenols nominated as endocrine disruptors. Degradation of branched 4-nonylphenol (mixture of isomers) has also been examined, and disappearance of its estrogenic activity was confirmed by means of the yeast two-hybrid assay. A gas chromatography-mass spectroscopy (GC-MS) analysis after solid-phase extraction indicates that the major product is cis,cis-4-alkyl-6-oxo-2,6-hexadienoic acids, and the minor products are 4-alkylcatechols and 4-(1-alkenyl)phenols.

  15. Photocatalytic degradation of some organic dyes under solar light irradiation using TiO2 and ZnO nanoparticles

    Directory of Open Access Journals (Sweden)

    Mojtaba Amini

    2016-01-01

    Full Text Available Nanoparticles of the ZnO and TiO2 were synthesized and the physicochemical properties of the compounds were characterized by IR, X-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM. The XRD patterns of the ZnO and TiO2 nanoparticles could be indexed to hexagonal and rutile phase, respectively. Aggregated nanoparticles of ZnO and TiO2 with spherical-like shapes were observed with particle diameter in the range of 80-100 nm. These nanoparticles were used for photocatalytic degradation of various dyes, Rhodamine B (RhB, Methylene blue (MB and Acridine orange (AO under solar light irradiation at room temperature. Effect of the amount of catalyst on the rate of photodegradation was investigated. In general, because ZnO is unstable, due to incongruous dissolution to yield Zn(OH2 on the ZnO particle surfaces and thus leading to catalyst inactivation,the catalytic activity of the system for photodegradation of dyes decreased dramatically when TiO2 was replaced by ZnO.

  16. Conversion of Carbon Dioxide by Methane Reforming under Visible-Light Irradiation: Surface-Plasmon-Mediated Nonpolar Molecule Activation.

    Science.gov (United States)

    Liu, Huimin; Meng, Xianguang; Dao, Thang Duy; Zhang, Huabin; Li, Peng; Chang, Kun; Wang, Tao; Li, Mu; Nagao, Tadaaki; Ye, Jinhua

    2015-09-21

    A novel CO2 photoreduction method, CO2 conversion through methane reforming into syngas (DRM) was adopted as an efficient approach to not only reduce the environmental concentration of the greenhouse gas CO2 but also realize the net energy storage from solar energy to chemical energy. For the first time it is reported that gold, which was generally regarded to be inactive in improving the performance of a catalyst in DRM under thermal conditions, enhanced the catalytic performance of Rh/SBA-15 in DRM under visible-light irradiation (1.7 times, CO2 conversion increased from 2100 to 3600 μmol g(-1) s(-1)). UV/Vis spectra and electromagnetic field simulation results revealed that the highly energetic electrons excited by local surface plasmon resonances of Au facilitated the polarization and activation of CO2 and CH4 with thermal assistance. This work provides a new route for CO2 photoreduction and offers a distinctive method to photocatalytically activate nonpolar molecules. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Sm2FeTaO7 Photocatalyst for Degradation of Indigo Carmine Dye under Solar Light Irradiation

    Directory of Open Access Journals (Sweden)

    Leticia M. Torres-Martínez

    2012-01-01

    Full Text Available This paper is focused to study Sm2FeTaO7 pyrochlore-type compound as solar photocatalyst for the degradation of indigo carmine dye in aqueous solution. Sm2FeTaO7 was synthesized by using conventional solid state reaction and sol-gel method. X-ray diffraction results indicated that Sm2FeTaO7 exhibit a monoclinic crystal structure. By scanning electron microscopy analysis, it was observed that sol-gel material presents particle size of around 150 nm. The specific surface area and energy bandgap values were 12 m2 g−1 and 2.0 eV, respectively. The photocatalytic results showed that indigo carmine molecule can be degraded under solar light irradiation using the synthesized materials, sol-gel photocatalyst was 8 times more active than solid state. On the other hand, when Sm2FeTaO7 was impregnated with CuO as cocatalyst the photocatalytic activity was increased because CuO acts as electron trap decreasing electron-hole pair recombination rates.

  18. Photocatalytic decomposition of Congo red under visible light irradiation using MgZnCr-TiO2 layered double hydroxide.

    Science.gov (United States)

    Ma, Chi; Wang, Fenghua; Zhang, Chang; Yu, Zhigang; Wei, Jingjing; Yang, Zhongzhu; Li, Yongqiu; Li, Zihao; Zhu, Mengying; Shen, Liuqing; Zeng, Guangming

    2017-02-01

    The new nanophotocatalyst MgZnCr-TiO2 was prepared by co-precipitation under different molar ratio of metals (Zn:Cr) and the loaded amount of TiO2. And it was characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy et al. Langmuir model fitted well the adsorption isotherm with the value of R2 0.9765, the maximum adsorption capacity was 526.32 mg g-1, the adsorption followed pseudo second order kinetic by MgZnCr-TiO2 (1:1:2-0.05). The photocatalytic oxidation of Congo red was used to determine the photocatalytic performance of MgZnCr-TiO2 (1:1:2-0.05) under visible light irradiation, and the removal rate reached 98% after reaction for 40 min. The degradation mechanism of Congo red also was proposed, and the MgZnCr-TiO2 (1:1:2-0.05) was stable after five cycles. Compared to the adsorption, Congo red was removed fundamentally by photocatalysis and it is expected to be an effective way to eliminate Congo red. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Photosensitized destruction of Chlorella vulgaris by Methylene Blue or Nuclear Fast Red combined with hydrogen peroxide under visible light irradiation.

    Science.gov (United States)

    McCullagh, Cathy; Robertson, Peter K J

    2006-04-01

    A considerable number of investigations have started to elucidate the essential roles biological agents play in the biodeterioration of stone. Chemical biocides are becoming increasingly banned because of the environmental and health hazards associated with these toxic substances. The present study reports the photodynamic effect of Methylene Blue (MB) and Nuclear Fast Red (NFR) in the presence of hydrogen peroxide (H2O2) on the destruction of the algae Chlorella vulgaris (C. vulgaris) under irradiation with visible light. Illumination of C. vulgaris in the presence of MB or NFR combined with H2O2 results in the decomposition of both the algal species and the photosensitizer. The photodynamic effect was investigated under aerobic and anaerobic conditions. Differences in mechanism type are reported and are dependent on both the presence and the absence of oxygen. The behavior of each photosensitizer leads to a Type II mechanism and a Type I/Type II combination for MB and NFR, respectively, being concluded. This novel combination could be effective for the remediation of biofilm-colonized stone surfaces.

  20. Characterization of Newly Synthesized ZrFe2O5 Nanomaterial and Investigations of Its Tremendous Photocatalytic Properties under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Shaukat Ali Shahid

    2013-01-01

    Full Text Available High functional ZrFe2O5 nanoparticles were synthesized using coprecipitation technique. The chemical composition of nanomaterials was studied by energy-dispersive X-ray (EDX. To observe the morphology, field emission scanning electron microscopy (FE-SEM was used. X-ray diffraction (XRD technique was utilized to appraise the structure of the synthesized material. The photocatalytic behavior of ZrFe2O5 nano-particles was investigated by measuring the degradation rate of toluidine blue O (TBO dye in aqueous solution in the presence of ZrFe2O5 nano-particles under visible light irradiation. A steady decrease in absorption peak under visible light irradiation was observed by increasing exposure time. The degradation efficiency was observed as 92% after 140 min of exposure to visible light. Besides, ZrFe2O5 nanophotocatalyst could be recovered and recycled easily. The rate of TBO and total organic carbon (TOC removal under visible light irradiation decreased by only 5% and 10%, respectively, after seven cycles of use, demonstrating the high photostability of the synthesized nano-photocatalyst material.

  1. On the role of localized surface plasmon resonance in UV-Vis light irradiated Au/TiO₂ photocatalysis systems: pros and cons.

    Science.gov (United States)

    Lin, Zhongjin; Wang, Xiaohong; Liu, Jun; Tian, Zunyi; Dai, Loucheng; He, Beibei; Han, Chao; Wu, Yigui; Zeng, Zhigang; Hu, Zhiyu

    2015-03-07

    The role of localized surface plasmon resonance (LSPR) in UV-Vis light irradiated Au/TiO2 photocatalysis systems has been investigated, and it is demonstrated experimentally for the first time that both pros and cons of LSPR exist simultaneously for this photocatalytic reaction. We have proved that when operating under mixed UV and green light irradiation, the LSPR injected hot electrons (from the Au nanoparticles to TiO2 under green light irradiation) may surmount the Schottky barrier (SB) formed between the Au nanoparticles and TiO2, and flow back into the TiO2. As a result, these electrons may compensate for and even surpass those transferred from TiO2 to the Au nanoparticles, thus accelerating the recombination of UV excited electron-hole pairs in TiO2. This is the negative effect of LSPR. On the other hand, more hot electrons existing on the surface of the Au nanoparticles due to LSPR would favor the photocatalytic reaction, which accompanied by the negative effect dominates the overall photocatalytic performance. The presented results reveal the multi-faceted essence of LSPR in Au/TiO2 structures, and is instructive for the application of metal-semiconductor composites in photocatalysis. Moreover, it is confirmed that the extent to which the above pros and cons of LSPR dominate the overall photocatalytic reaction depends on the intensity ratio of visible to UV light.

  2. Silicon isotope separation utilizing infrared multiphoton dissociation of Si{sub 2}F{sub 6} irradiated with two-color CO{sub 2} laser light

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Atsushi; Ohba, Hironori; Hashimoto, Masashi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ishii, Takeshi; Ohya, Akio [Nuclear Development Corp., Tokai, Ibaraki (Japan); Arai, Shigeyoshi [Hill Research Co. Ltd., Tokyo (Japan)

    2002-08-01

    Silicon isotope separation has been done by utilizing the Infrared Multiphoton Dissociation (IRMPD) of Si{sub 2}F{sub 6} irradiated with two-color CO{sub 2} laser lights. The two-color excitation method improved the separation efficiency keeping the high enrichment factors. For example, 99.74% of {sup 28}Si was obtained at 49.63% dissociation of Si{sub 2}F{sub 6} after the simultaneous irradiation of 200 pulses with 966.23 cm{sup -1} photons (0.084 J/cm{sup 2}) and 954.55 cm{sup -1} photons (0.658 J/cm{sup 2}), while 2000 pulses were needed to obtain 99.35% of {sup 28}Si at 35.6% dissociation in the case of only one-color irradiation at 954.55 cm{sup -1} (0.97 J/cm{sup 2}). (author)

  3. Iron promotion of the TiO{sub 2} photosensitization process towards the photocatalytic oxidation of azo dyes under solar-simulated light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Camilo A.; Centeno, Aristobulo [Centro de Investigaciones en Catalisis (CICAT), Escuela de Ingenieria Quimica, Universidad Industrial de Santander (UIS), A.A. 678, Bucaramanga (Colombia); Giraldo, Sonia A., E-mail: sgiraldo@uis.edu.co [Centro de Investigaciones en Catalisis (CICAT), Escuela de Ingenieria Quimica, Universidad Industrial de Santander (UIS), A.A. 678, Bucaramanga (Colombia)

    2011-10-03

    Highlights: {yields} Azo dye photooxidation occurs under strict combination of ultraviolet and visible irradiation of Fe-TiO{sub 2}. {yields} Fe{sup 3+} enhances the TiO{sub 2} photooxidation of azo dyes while decreases that of phenol. {yields} UV irradiation leads to a decrease in photooxidation activity of Fe-TiO{sub 2} photocatalysts. - Abstract: The photocatalytic oxidation of the azo dye Orange-II (Or-II) using Fe loaded TiO{sub 2} (Fe-TiO{sub 2}) was studied under ultraviolet (UV), visible (vis) and simultaneous UV-vis irradiations using a solar light simulator. Photocatalysts were characterized by means of XRD, SEM-EDX, FTIR and DRS. Fe{sup 3+} species, identified in XPS analyses, were responsible of the increased absorption of visible light. Moreover, DRS analyses showed a decrease in the bandgap due to Fe{sup 3+} loading. Photocatalystic tests proved that Fe modification enhanced the TiO{sub 2} photocatalytic activity towards Or-II photodegradation under simultaneous UV-vis irradiation. Even so, the performance of the Fe-TiO{sub 2} samples towards the photodegradation of phenol, under UV irradiation, was lower than TiO{sub 2} suggesting the recombination of the UV photogenerated electron-hole pair. Therefore, results evidence a Fe{sup 3+} promotion of the electron caption in the photosensitization process of TiO{sub 2} by Or-II acting as a sensitizer. Such process leads to the Or-II photooxidation under UV-vis irradiation by losing energy in electron transferring processes to sensitize TiO{sub 2}, and, the formation of reactive oxygen species promoted by the injected electron to the TiO{sub 2} conduction band.

  4. In Vitro Bactericidal Effects of 625, 525, and 425 nm Wavelength (Red, Green, and Blue) Light-Emitting Diode Irradiation

    Science.gov (United States)

    Kim, SangWoo; Kim, JiSun; Lim, WonBong; Jeon, SangMi; Kim, OkSu; Koh, Jeong-Tae; Kim, Chang-Su; Choi, HongRan

    2013-01-01

    Abstract Objective: The purpose of this study was to evaluate the relationship of 625, 525, and 425 nm wavelengths, providing average power output and effects on three common pathogenic bacteria. Background data: Ultraviolet (UV) light kills bacteria, but the bactericidal effects of UV may not be unique, as 425 nm produces a similar effect. The bactericidal effects of light-emitting diode (LED) wavelengths such as 625 and 525 nm have not been described. Before conducting clinical trials, the appropriate wavelength with reasonable dose and exposure time should be established. Materials and methods: The bactericidal effects of 625, 525, and 425 nm wavelength LED irradiation were investigated in vitro for the anaerobic bacterium Porphyromonas gingivalis and two aerobes (Staphylococcus aureus and Escherichia coli DH5α). Average power output was 6 mW/cm2 for 1 h. The bacteria were exposed to LED irradiation for 1, 2, 4, and 8 h (21.6, 43.2, 86.4, and 172.8 J/cm2, respectively). LED irradiation was performed during growth on agar and in broth. Control bacteria were incubated without LED irradiation. Bacterial growth was expressed in colony-forming units (CFU) and at an optical density at 600 nm in agar and broth. Results: The bactericidal effect of LED phototherapy depended upon wavelength, power density, bacterial viable number, and bacteria species. The bactericidal effect of 425 and 525 nm irradiation varied depending upon the bacterial inoculation, compared with unirradiated samples and samples irradiated with red light. Especially, P. gingivalis and E. coli DH5α were killed by 425 nm, and S. aureus growth was inhibited by 525 nm. However, the wavelength of 625 nm was not bactericidal for P. gingivalis, E. coli DH5α, or S. aureus. Conclusions: Irradiation at 625 nm light was not bactericidal to S. aureus, E. coli, and P. gingivalis, whereas wavelengths of 425 and 525 nm had bactericidal effects. S. aureus was also killed at 525

  5. Induction of primitive pigment cell differentiation by visible light (helium-neon laser): a photoacceptor-specific response not replicable by UVB irradiation.

    Science.gov (United States)

    Lan, Cheng-Che E; Wu, Shi-Bei; Wu, Ching-Shuang; Shen, Yi-Chun; Chiang, Tzu-Ying; Wei, Yau-Huei; Yu, Hsin-Su

    2012-03-01

    Solar lights encompass ultraviolet (UV), visible, and infrared spectrum. Most previous studies focused on the harmful UV effects, and the biologic effects of lights at other spectrums remained unclear. Recently, lights at visible region have been used for regenerative purposes. Using the process of vitiligo repigmentation as a research model, we focused on elucidating the pro-differentiation effects induced by visible light. We first showed that helium-neon (He-Ne) laser (632.8 nm) irradiation stimulated differentiation of primitive pigment cells, an effect not replicable by UVB treatment even at high and damaging doses. In addition, significant increases of mitochondrial DNA copy number and the regulatory genes for mitochondrial biogenesis were induced by He-Ne laser irradiation. Mechanistically, we demonstrated that He-Ne laser initiated mitochondrial retrograde signaling via a Ca(2+)-dependent cascade. The impact on cytochrome c oxidase within the mitochondria is responsible for the efficacy of He-Ne laser in promoting melanoblast differentiation. Taken together, we propose that visible lights from the sun provide important environmental cues for the relatively quiescent stem or primitive cells to differentiate. In addition, our results also indicate that visible light may be used for regenerative medical purposes involving stem cells.

  6. Thermography Applied During Exercises With or Without Infrared Light-Emitting Diode Irradiation: Individual and Comparative Analysis

    Science.gov (United States)

    Lins, Emery C.; Corazza, Adalberto Vieira; Kurachi, Cristina; Bagnato, Vanderlei Salvador

    2013-01-01

    Abstract Objective: The aim of our study was to evaluate the cutaneous temperature during an exercise on a treadmill with or without infrared light-emitting diode (LED) irradiation in postmenopausal women. Background data: Thermography is an imaging technique in which radiation emitted by a body in the middle and far infrared spectrum is detected and associated with the temperature of the body's surface. Materials and methods: Eighteen postmenopausal women were randomly divided into two groups: (1) the LED group, which performed the exercises on a treadmill associated with phototherapy (n=9) and; (2) the exercise group, which performed the exercises on a treadmill without additional phototherapy (n=9). The irradiation parameters for each women's thigh were: array of 2000 infrared LEDs (850 nm) with an area of 1,110 cm2, 100 mW, 39 mW/cm2, and 108 J/cm2 for 45 min. The submaximal constant-speed exercise on the treadmill at intensities between 85% and 90% maximal heart rate (HRmax) with or without phototherapy were performed during 45 min, to perform the thermographic analysis. Thermography images were captured before the exercise (t=0), after 10, 35, and 45 min of exercising (t=10, t=35, and t=45) and at 5 min post-exercising (t=50). Results: The LED group showed an increased cutaneous thigh temperature during the exercise (from 33.5±0.8°C to 34.6±0.9°C, p=0.03), whereas the exercise group showed a reduced cutaneous temperature (from 33.5±0.6 to 32.7±0.7°C, p=0.02). The difference between the groups was significant (p<0.05) at t=35, t=45, and t=50. Conclusions: These data indicate an improved microcirculation, and can explain one possible mechanism of action of phototherapy associated with physical exercises. PMID:23819505

  7. Effectiveness of UV-C light irradiation on disinfection of an eSOS(®) smart toilet evaluated in a temporary settlement in the Philippines.

    Science.gov (United States)

    Zakaria, Fiona; Harelimana, Bertin; Ćurko, Josip; van de Vossenberg, Jack; Garcia, Hector A; Hooijmans, Christine Maria; Brdjanovic, Damir

    2016-01-01

    Ultraviolet germicidal (short wavelength UV-C) light was studied as surface disinfectant in an Emergency Sanitation Operation System(®) smart toilet to aid to the work of manual cleaning. The UV-C light was installed and regulated as a self-cleaning feature of the toilet, which automatically irradiate after each toilet use. Two experimental phases were conducted i.e. preparatory phase consists of tests under laboratory conditions and field testing phase. The laboratory UV test indicated that irradiation for 10 min with medium-low intensity of 0.15-0.4 W/m(2) could achieve 6.5 log removal of Escherichia coli. Field testing of the toilet under real usage found that UV-C irradiation was capable to inactivate total coliform at toilet surfaces within 167-cm distance from the UV-C lamp (UV-C dose between 1.88 and 2.74 mW). UV-C irradiation is most effective with the support of effective manual cleaning. Application of UV-C for surface disinfection in emergency toilets could potentially reduce public health risks.

  8. Effects of the antimicrobial peptide cathelicidin (LL-37) on immortalized gingival fibroblasts infected with Porphyromonas gingivalis and irradiated with 625-nm LED light.

    Science.gov (United States)

    Kim, JiSun; Kim, SangWoo; Lim, WonBong; Choi, HongRan; Kim, OkJoon

    2015-11-01

    Porphyromonas gingivalis causes chronic inflammatory diseases (periodontal diseases) that destroy the periodontal ligament and alveolar bone. Antimicrobial peptides are crucial components of the host defense response required to maintain cellular homeostasis during microbial invasion. Because light-emitting diode (LED) irradiation influences the host defense response against bacterial infections, we investigated its effect on immortalized gingival fibroblasts (IGFs) infected with P. gingivalis. IGFs were incubated with P. gingivalis following LED irradiation at 425, 525, and 625 nm. The dark 1 group comprised noninfected, nonirradiated IGFs, and the dark 2 group comprised nonirradiated IGFs infected with P. gingivalis. These groups served as controls. Infected cells and controls were assayed for reactive oxygen species (ROS) and were subjected to RT-PCR and Western blotting analyses to determine the levels of expression of antimicrobial peptides. LED irradiation enhanced the bactericidal effects of the antimicrobial peptide LL-37 in cells infected with P. gingivalis. Irradiation at 625 nm decreased inflammatory responses involving the release of prostaglandin E2 induced by ROS in P. gingivalis-infected IGFs. LED irradiation at 625 nm induces an anti-inflammatory response that elicits the production of antimicrobial peptides, providing an efficacious method of treatment for periodontal diseases.

  9. Determination of 2-alkylcyclobutanones in ultraviolet light-irradiated fatty acids, triglycerides, corn oil, and pork samples: Identifying a new source of 2-alkylcyclobutanones.

    Science.gov (United States)

    Meng, Xiangpeng; Chan, Wan

    2017-02-15

    Previous studies have established that 2-alkylcyclobutanones (2-ACBs) are unique radiolytic products in lipid-containing foods that could only be formed through exposure to ionizing radiation, but not by any other means of physical/heat treatment methods. Therefore, 2-ACBs are currently the marker molecules required by the European Committee for Standardization to be used to identify foods irradiated with ionizing irradiation. Using a spectrum of state-of-the-art analytical instruments, we present in this study for the first time that the generation of 2-ACBs was also possible when fatty acids and triglycerides are exposed to a non-ionizing, short-wavelength ultraviolet (UV-C) light source. An irradiation dosage-dependent formation of 2-ACBs was also observed in UV-C irradiated fatty acids, triglycerides, corn oil, and pork samples. With UV-C irradiation becoming an increasingly common food treatment procedure, it is anticipated that the results from this study will alert food scientists and regulatory officials to a potential new source for 2-ACBs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Use of an Autonomous Surface Vehicle reveals small-scale diel vertical migrations of zooplankton and susceptibility to light pollution under low solar irradiance.

    Science.gov (United States)

    Ludvigsen, Martin; Berge, Jørgen; Geoffroy, Maxime; Cohen, Jonathan H; De La Torre, Pedro R; Nornes, Stein M; Singh, Hanumant; Sørensen, Asgeir J; Daase, Malin; Johnsen, Geir

    2018-01-01

    Light is a major cue for nearly all life on Earth. However, most of our knowledge concerning the importance of light is based on organisms' response to light during daytime, including the dusk and dawn phase. When it is dark, light is most often considered as pollution, with increasing appreciation of its negative ecological effects. Using an Autonomous Surface Vehicle fitted with a hyperspectral irradiance sensor and an acoustic profiler, we detected and quantified the behavior of zooplankton in an unpolluted light environment in the high Arctic polar night and compared the results with that from a light-polluted environment close to our research vessels. First, in environments free of light pollution, the zooplankton community is intimately connected to the ambient light regime and performs synchronized diel vertical migrations in the upper 30 m despite the sun never rising above the horizon. Second, the vast majority of the pelagic community exhibits a strong light-escape response in the presence of artificial light, observed down to 100 m. We conclude that artificial light from traditional sampling platforms affects the zooplankton community to a degree where it is impossible to examine its abundance and natural rhythms within the upper 100 m. This study underscores the need to adjust sampling platforms, particularly in dim-light conditions, to capture relevant physical and biological data for ecological studies. It also highlights a previously unchartered susceptibility to light pollution in a region destined to see significant changes in light climate due to a reduced ice cover and an increased anthropogenic activity.

  11. Influence of the spectral distribution of light on the characteristics of photovoltaic panel. Comparison between simulation and experimental

    Science.gov (United States)

    Chadel, Meriem; Bouzaki, Mohammed Moustafa; Chadel, Asma; Petit, Pierre; Sawicki, Jean-Paul; Aillerie, Michel; Benyoucef, Boumediene

    2017-02-01

    We present and analyze experimental results obtained with a laboratory setup based on a hardware and smart instrumentation for the complete study of performance of PV panels using for illumination an artificial radiation source (Halogen lamps). Associated to an accurate analysis, this global experimental procedure allows the determination of effective performance under standard conditions thanks to a simulation process originally developed under Matlab software environment. The uniformity of the irradiated surface was checked by simulation of the light field. We studied the response of standard commercial photovoltaic panels under enlightenment measured by a spectrometer with different spectra for two sources, halogen lamps and sunlight. Then, we bring a special attention to the influence of the spectral distribution of light on the characteristics of photovoltaic panel, that we have performed as a function of temperature and for different illuminations with dedicated measurements and studies of the open circuit voltage and short-circuit current.

  12. Ag loaded WO{sub 3} nanoplates for efficient photocatalytic degradation of sulfanilamide and their bactericidal effect under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wenyu [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141 (Singapore); Liu, Jincheng, E-mail: JCLIU@ntu.edu.sg [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Current address: Faculty of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510009 (China); Yu, Shuyan; Zhou, Yan [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141 (Singapore); Yan, Xiaoli, E-mail: XLYAN@ntu.edu.sg [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Current address: Environmental and Water Technology Centre of Innovation, Ngee Ann Polytechnic, 535 Clementi Road, Singapore 599489 (Singapore)

    2016-11-15

    Highlights: • WO{sub 3}/Ag heterogeneous composites were fabricated with simply photo-reduction method. • Property changes due to Ag loading were systematically studied. • WO{sub 3}/Ag composites efficiently degraded sulfanilamide under visible light irradiation. • WO{sub 3}/Ag composites exhibited bactericidal effectS under visible light irradiation. - Abstract: Sulfonamides (SAs) are extensively used antibiotics and their residues in the water bodies propose potential threat to the public. In this study, degradation efficiency of sulfanilamide (SAM), which is the precursor of SAs, using WO{sub 3} nanoplates and their Ag heterogeneous as photocatalysts was investigated. WO{sub 3} nanoplates with uniform size were synthesized by a facile one step hydrothermal method. Different amount of Ag nanoparticles (Ag NPs) were loaded onto WO{sub 3} nanoplates using a photo-reduction method to generate WO{sub 3}/Ag composites. The physio-chemical properties of synthesized nanomaterials were systematically characterized. Photodegradation of SAM by WO{sub 3} and WO{sub 3}/Ag composites was conducted under visible light irradiation. The results show that WO{sub 3}/Ag composites performed much better than pure WO{sub 3} where the highest removal rate was 96.2% in 5 h. Ag as excellent antibacterial agent also endows certain antibacterial efficiency to WO{sub 3}, and 100% removal efficiency against Escherichia Coli and Bacillus subtilis could be achieved in 2 h under visible light irradiation for all three WO{sub 3}/Ag composites synthesized. The improved performance in terms of SAM degradation and antibacterial activity of WO{sub 3}/Ag can be attributed to the improved electron-hole pair separation rate where Ag NPs act as effective electron trapper during the photocatalytic process.

  13. Influence of visible-light irradiation on physicochemical and photocatalytic properties of nitrogen-doped three-dimensional (3D) titanium dioxide.

    Science.gov (United States)

    Lee, Hyun Uk; Lee, Soon Chang; Choi, Saehae; Son, Byoungchul; Kim, Hyeran; Lee, Sang Moon; Kim, Hae Jin; Lee, Jouhahn

    2013-08-15

    We report highly active visible-light driven nitrogen-doped three-dimensional polycrystalline anatase TiO2 photocatalysts (N-3D TiO2) for environmental and biomedical applications. N-3D TiO2 is synthesized at a low temperature (<90°C) without thermal treatment via a modified hydrothermal process (HP) and ultrasound irradiation (UI). The N-3D TiO2 is additionally irradiated with visible-light to improve the hydroxylation of its surface. Under visible-light irradiation, the photocatalytic activity of visible-light irradiated N-3D TiO2 (*N-3D TiO2; [k]=1.435 h(-1)) is 26.1 times higher than that of 3D TiO2 ([k]=0.055 h(-1)). The *N-3D TiO2 is highly recyclable and retained 91.8% of the initial decolorization rate after fifteen cycles. Interestingly, the *N-3D TiO2 shows very strong antibacterial properties against both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) after exposure to visible-light for 3h. The antibacterial properties of *N-3D TiO2 are more effective than those of TiO2, 3D TiO2, and N-3D TiO2. More than 91.3% of the E. coli is sterilized after ten cycles. There are a large increase in the photocatalytic and antibacterial activity of *N-3D TiO2 relative to that of N-3D TiO2 owing to the hydroxylation of the N-3D TiO2 surface as a result of the visible-light irradiation. These results indicate that *N-3D TiO2 might have utility in several promising applications such as highly efficient water/air treatment, inactivation of pathogenic microorganisms, and solar-energy conversion. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Ultrasonic-assisted one-pot preparation of ZnO/Ag3VO4 nanocomposites for efficiently degradation of organic pollutants under visible-light irradiation

    Science.gov (United States)

    Kiantazh, Fariba; Habibi-Yangjeh, Aziz

    2015-11-01

    We report a facile ultrasonic-assisted one-pot method for preparation of ZnO/Ag3VO4 nanocomposites with different mole fractions of silver vanadate. The preparation method has considerable merits such as short preparation time, large-scale, and one-pot strategy. The resultant samples were fairly characterized by means of XRD, EDX, SEM, TEM, UV-vis DRS, FT-IR, and PL techniques. Visible-light activity of the resultant samples was investigated by degradation of rhodamine B (RhB), methylene blue (MB), and methyl orange (MO). Among the prepared nanocomposites, the ZnO/Ag3VO4 nanocomposite with 0.073 mole fraction of Ag3VO4 exhibited the best activity and excessive amount of Ag3VO4 resulted in decrease of the activity. Photocatalytic activity of this nanocomposite under visible-light irradiation is about 21, 56, and 2.8-fold higher than that of the ZnO sample in degradation of RhB, MB, and MO, respectively. The highly enhanced activity of the nanocomposite was attributed to greater generation of electron-hole pairs, due to photosensitizing role of Ag3VO4 under visible-light irradiation, and efficiently separation of the photogenerated electron-hole pairs, due to formation of n-n heterojunction between the counterparts. Furthermore, it was revealed that the photocatalytic activity largely depends on ultrasonic irradiation time, calcination temperature, and scavengers of the reactive species.

  15. Synthesis, characterization and photocatalytic activity of WO{sub 3}/TiO{sub 2} for NO removal under UV and visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Luévano-Hipólito, E. [CIIDIT, Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Martínez-de la Cruz, A., E-mail: azael.martinezdl@uanl.edu.mx [CIIDIT, Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); López-Cuellar, E. [CIIDIT, Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Yu, Q.L.; Brouwers, H.J.H. [Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2014-11-14

    Samples with different proportions WO{sub 3}/TiO{sub 2} were prepared by co-precipitation method followed by a heat treatment. The samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), and adsorption–desorption N{sub 2} isotherms (BET). The photocatalytic properties of WO{sub 3}/TiO{sub 2} samples were evaluated in the photo-oxidation reaction of nitric oxide (NO) under UV and visible light irradiation. The highest photocatalytic activity was observed in the WO{sub 3}/TiO{sub 2} sample with a composition of 80% mole of TiO{sub 2}. Among the different substrates used for supporting the photocatalyst, the best results were reached over concrete and glass when it was exposed to UV and visible light irradiation, respectively. In overall, the photocatalytic efficiency of the synthesized materials was higher under UV than visible light irradiation. - Highlights: • WO{sub 3}/TiO{sub 2} prepared in simple way show high photocatalytic activity for NO removal. • The concrete was the best substrate to the performance of WO{sub 3}/TiO{sub 2} with UV radiation. • The glass was the best substrate to the performance of WO{sub 3}/TiO{sub 2} with visible radiation.

  16. Technology for radiation efficiency measurement of high-power halogen tungsten lamp used in calibration of high-energy laser energy meter.

    Science.gov (United States)

    Wei, Ji Feng; Hu, Xiao Yang; Sun, Li Qun; Zhang, Kai; Chang, Yan

    2015-03-20

    The calibration method using a high-power halogen tungsten lamp as a calibration source has many advantages such as strong equivalence and high power, so it is very fit for the calibration of high-energy laser energy meters. However, high-power halogen tungsten lamps after power-off still reserve much residual energy and continually radiate energy, which is difficult to be measured. Two measuring systems were found to solve the problems. One system is composed of an integrating sphere and two optical spectrometers, which can accurately characterize the radiative spectra and power-time variation of the halogen tungsten lamp. This measuring system was then calibrated using a normal halogen tungsten lamp made of the same material as the high-power halogen tungsten lamp. In this way, the radiation efficiency of the halogen tungsten lamp after power-off can be quantitatively measured. In the other measuring system, a wide-spectrum power meter was installed far away from the halogen tungsten lamp; thus, the lamp can be regarded as a point light source. The radiation efficiency of residual energy from the halogen tungsten lamp was computed on the basis of geometrical relations. The results show that the halogen tungsten lamp's radiation efficiency was improved with power-on time but did not change under constant power-on time/energy. All the tested halogen tungsten lamps reached 89.3% of radiation efficiency at 50 s after power-on. After power-off, the residual energy in the halogen tungsten lamp gradually dropped to less than 10% of the initial radiation power, and the radiation efficiency changed with time. The final total radiation energy was decided by the halogen tungsten lamp's radiation efficiency, the radiation efficiency of residual energy, and the total power consumption. The measuring uncertainty of total radiation energy was 2.4% (here, the confidence factor is two).

  17. Integrated Bi2O3 nanostructure modified with Au nanoparticles for enhanced photocatalytic activity under visible light irradiation

    Directory of Open Access Journals (Sweden)

    Hankwon Lim

    2017-06-01

    Full Text Available An integrated Bi2O3 (i-Bi2O3 nanostructure with a particle size 10 nm inducing agglomerated structure were synthesized by dissolving bismuth nitrate pentahydrate in diethylene glycol at 180 °C with post heat treatment. The prepared i-Bi2O3 nanostructures were employed for the construction of Au/i-Bi2O3 composite system and characterized by X-ray diffraction pattern, UV–visible diffuse reflectance spectroscopy (DRS, and transmission electron microscopy, X-ray photoemission spectroscopy (XPS and Energy dispersive X-ray spectroscopy (EDS. The i-Bi2O3 nanostructure and Au/i-Bi2O3 composite system were found to exhibit high photocatalytic activity than commercial Bi2O3 in decomposing salicylic acid under visible light irradiation. The high catalytic activity of i-Bi2O3 nanostructure was deduced to be caused by charge separation facilitated by electron hopping between the particles within the integrated structure and space-charge separation between i-Bi2O3 and Au. The charge separation behavior in i-Bi2O3 nanostructure was further bolstered by comparing the measured. OH radical produced in the solution with i-Bi2O3 nanostructure, commercial Bi2O3 and Au/i-Bi2O3 composite which readily react with 1,4-terephthalic acid (TA inducing 2-hydroxy terephthalic acid (TAOH that shows unique fluorescence peak at 426 nm. The space-charge separation between i-Bi2O3 and Au was confirmed by measuring the electron spin resonance (ESR spectra.

  18. Metastable β-Bi2O3 Nanoparticles with Potential for Photocatalytic Water Purification Using Visible Light Irradiation.

    Science.gov (United States)

    Schlesinger, Maik; Weber, Marcus; Schulze, Steffen; Hietschold, Michael; Mehring, Michael

    2013-08-01

    Photocatalytic studies under visible light irradiation using nanosized β-Bi2O3 are reported. β-Bi2O3 nanoparticles are prepared starting from the well-defined bismuth oxido cluster [Bi38O45(OMc)24(DMSO)9]⋅2 DMSO⋅7 H2O (OMc=O2CC3H5) using a straightforward hydrolysis and annealing protocol. Powder X-ray diffraction studies, transmission electron microscopy, diffuse reflectance UV/Vis spectroscopy and nitrogen adsorption measurements (using the Brunauer-Emmett-Teller (BET) theory) are used for the characterization of the as-prepared β-Bi2O3. By time-dependent annealing, the crystallite size can be controlled between (17±2) nm and (45±5) nm with BET surface areas of 7 to 29 m(2) g(-1). The indirect band gap of the as-prepared β-Bi2O3 amounts to (2.15±0.05) eV. The decomposition rates for rhodamine B (RhB) solutions are in the range of 2.46×10(-5) to 4.01×10(-4) s(-1) and depend on the crystallite size, amount of catalyst and concentration of RhB. Photocorrosion experiments have shown the formation of Bi2O2CO3 after several catalytic cycles. However, the catalyst can be recycled to phase-pure β-Bi2O3 nanoparticles by annealing for one hour under argon atmosphere at 380 °C. Furthermore, the photocatalytic activity of as-prepared β-Bi2O3 nanoparticles for the decomposition of phenol, 4-chlorophenol, 2,4-dichlorphenol, 4-nitrophenol, triclosan and ethinyl estradiol is demonstrated.

  19. The classical photoactivated drug 8-methoxypsoralen and related compounds are effective without UV light irradiation against glioma cells.

    Science.gov (United States)

    de Oliveira, Diêgo Madureira; Ferreira Lima, Rute Maria; Clarencio, Jorge; Velozo, Eudes da Silva; de Amorim, Ilza Alves; Andrade da Mota, Tales Henrique; Costa, Silvia Lima; Silva, Fábio Pittella; El-Bachá, Ramon Dos Santos

    2016-10-01

    Currently, there is no effective therapy for high grade gliomas. 8-Methoxypsoralen (8-MOP) is a compound used in the treatment of skin diseases combined with UV light irradiation. In this work, rat glioma C6 cells, normal astrocytes and human glioblastoma GL-15 cells comprised an in vitro model to evaluate the antitumor activity of 8-MOP. We found that 8-MOP promoted a time- and concentration-dependent reduction of cell viability in tumor, but not in normal cells. This effect was more evident in log-phase growing culture, indicating antiproliferative activity, which was confirmed by colony formation assay. Long-term effect of 8-MOP at low concentration was also attested. The concentrations used in the tests (0.02-0.4 mM) were lower than plasmatic concentration found in patients. Despite the treatment leads to considerable morphological changes and apoptosis when used at high concentrations, 8-MOP did not promote cell cycle arrest, change in migration pattern neither necrosis. In addition, we evaluated the effect of 8-MOP in MDA-MB-231, CT-26 and SCC-3 cell lines, derived from other kind of primary tumors, and found that CT-26 cells did not respond to 8-MOP treatment, indicating that this compound does not act through a generic mechanism. Coumarin derivatives structurally related to 8-MOP were screened for its antitumor potential and presented different patterns of biological activity, and then it was possible to suggest the relevance of 8-MOP molecular structure for antiproliferative action. Therefore, 8-MOP, a drug with an outstanding record of safety, and related coumarins are good prototypes for development of a new class of anti-glioma drugs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Accumulation of Phenylpropanoids by White, Blue, and Red Light Irradiation and Their Organ-Specific Distribution in Chinese Cabbage (Brassica rapa ssp. pekinensis).

    Science.gov (United States)

    Kim, Yeon Jeong; Kim, Yeon Bok; Li, Xiaohua; Choi, Su Ryun; Park, Suhyoung; Park, Jong Seok; Lim, Yong Pyo; Park, Sang Un

    2015-08-05

    This study investigated optimum light conditions for enhancing phenylpropanoid biosynthesis and the distribution of phenylpropanoids in organs of Chinese cabbage (Brassica rapa ssp. pekinensis). Blue light caused a high accumulation of most phenolic compounds, including p-hydroxybenzoic acid, ferulic acid, quercetin, and kaempferol, at 12 days after irradiation (DAI). This increase was coincident with a noticeable increase in expression levels of BrF3H, BrF3'H, BrFLS, and BrDFR. Red light led to the highest ferulic acid content at 12 DAI and to elevated expression of the corresponding genes during the early stages of irradiation. White light induced the highest accumulation of kaempferol and increased expression of BrPAL and BrDFR at 9 DAI. The phenylpropanoid content analysis in different organs revealed organ-specific accumulation of p-hydroxybenzoic acid, quercetin, and kaempferol. These results demonstrate that blue light is effective at increasing phenylpropanoid biosynthesis in Chinese cabbage, with leaves and flowers representing the most suitable organs for the production of specific phenylpropanoids.

  1. Organic halogens in spruce forest throughfall

    DEFF Research Database (Denmark)

    Öberg, G.; Johansen, C.; Grøn, C.

    1998-01-01

    Deposition of dissolved organic halogens by throughfall was determined in a small spruce forest site in Denmark (56 degrees 28'N, 8 degrees 24'E). The mean annual deposition of dissolved organic halogens was 377 g ha(-1)yr(-1), and larger than the general deposition by precipitation....... No relationship between the position of the collectors and the forest edge or dominating wind-direction was found, suggesting that dry deposition was not a major source. The concentration of organic halogens was related to that of organic carbon and decreased from the tree-trunk and outwards. In addition......, the concentrations were higher during the growing season than during the dormant season. This indicates that the major part of the organic carbon and organic halogens in spruce forest throughfall originates from canopy leachates or other internal sources. (C) 1998 Elsevier Science Ltd....

  2. Informative document halogenated hydrocarbon-containing waste

    NARCIS (Netherlands)

    Verhagen H

    1992-01-01

    This "Informative document halogenated hydrocarbon-containing waste" forms part of a series of "Informative documents waste materials". These documents are conducted by RIVM on the instructions of the Directorate General for the Environment, Waste Materials Directorate, in

  3. Photocatalytic activity of attapulgite–BiOCl–TiO{sub 2} toward degradation of methyl orange under UV and visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lili, E-mail: zll@hytc.edu.cn; Zhang, Jiahui; Zhang, Weiguang; Liu, Jianquan; Zhong, Hui; Zhao, Yijiang

    2015-06-15

    Highlights: • Excellent photocatalyst was obtained by introducing BiOCl–TiO{sub 2} onto attapulgite. • 100 mg L{sup −1} methyl orange (MO) was totally decomposed under UV light within 70 min. • 92.6% of 10 mg L{sup −1} MO was decomposed within 120 min under visible light. • ATT–BiOCl–TiO{sub 2} show better activity than P{sub 25} especially under visible light. • Mechanism of photocatalytic activity enhancement was identified. - Abstract: An environmental friendly composite photocatalyst with efficient UV and visible light activity has been synthesized by introducing BiOCl–TiO{sub 2} hybrid oxide onto the surface of attapulgite (ATT) (denoted as ATT–BiOCl–TiO{sub 2}), using a simple in situ depositing technique. The obtained products were characterized by XRD, TEM, BET and UV–vis diffuse reflectance spectra measurements. Results showed that BiOCl–TiO{sub 2} composite particles were successfully loaded onto attapulgite fibers' surface without obvious aggregation. The photocatalytic activity of ATT–BiOCl–TiO{sub 2} was investigated by degradation of methyl orange under UV and visible light irradiation. It was found that 100 mg L{sup −1} methyl orange was totally decomposed under UV light within 70 min and 92.57% of 10 mg L{sup −1} methyl orange was decomposed under visible light within 120 min using ATT–BiOCl–TiO{sub 2} as photocatalyst. These results were quite better than that of P{sub 25}, especially under visible light irradiation. Possible mechanism for the enhancement was proposed.

  4. Halogen-specific total organic halogen analysis: Assessment by recovery of total bromine.

    Science.gov (United States)

    Langsa, Markus; Allard, Sebastien; Kristiana, Ina; Heitz, Anna; Joll, Cynthia A

    2017-08-01

    Determination of halogen-specific total organic halogen (TOX) is vital for studies of disinfection of waters containing bromide, since total organic bromine (TOBr) is likely to be more problematic than total organic chlorine. Here, we present further halogen-specific TOX method optimisation and validation, focusing on measurement of TOBr. The optimised halogen-specific TOX method was validated based on the recovery of model compounds covering different classes of disinfection by-products (haloacetic acids, haloacetonitriles, halophenols and halogenated benzenes) and the recovery of total bromine (mass balance of TOBr and bromide concentrations) during disinfection of waters containing dissolved organic matter and bromide. The validation of a halogen-specific TOX method based on the mass balance of total bromine has not previously been reported. Very good recoveries of organic halogen from all model compounds were obtained, indicating high or complete conversion of all organic halogen in the model compound solution through to halide in the absorber solution for ion chromatography analysis. The method was also successfully applied to monitor conversion of bromide to TOBr in a groundwater treatment plant. An excellent recovery (101%) of total bromine was observed from the raw water to the post-chlorination stage. Excellent recoveries of total bromine (92%-95%) were also obtained from chlorination of a synthetic water containing dissolved organic matter and bromide, demonstrating the validity of the halogen-specific TOX method for TOBr measurement. The halogen-specific TOX method is an important tool to monitor and better understand the formation of halogenated organic compounds, in particular brominated organic compounds, in drinking water systems. Copyright © 2017. Published by Elsevier B.V.

  5. Adoption of Light-Emitting Diodes in Common Lighting Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Mary [Navigant, Chicago, IL (United States); Stober, Kelsey [Navigant, Chicago, IL (United States)

    2015-07-01

    Report estimating LED energy savings between 2012 and 2014 in 10 applications where LEDs competed with traditional lighting sources such as incandescent, halogen, high-pressure sodium, and fluorescent. The analysis includes indoor lamp, indoor luminaire, and outdoor luminaire applications.

  6. Adoption of Light-Emitting Diodes in Common Lighting Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Mary [Navigant Consulting, Suwanee, GA (United States); Chwastyk, Dan [Navigant Consulting, Suwanee, GA (United States)

    2013-05-01

    Report estimating LED energy savings in nine applications where LEDs compete with traditional lighting sources such as incandescent, halogen, high-pressure sodium, and certain types of fluorescent. The analysis includes indoor lamp, indoor luminaire, and outdoor luminaire applications.

  7. Interspecific prediction of photosynthetic light response curves using specific leaf mass and leaf nitrogen content: effects of differences in soil fertility and growth irradiance.

    Science.gov (United States)

    Lachapelle, Pierre-Philippe; Shipley, Bill

    2012-05-01

    Previous work has shown that the entire photosynthetic light response curve, based on both Mitscherlich and Michaelis-Menten functions, could be predicted in an interspecific context through allometric relations linking the parameters of these functions to two static leaf traits: leaf nitrogen (N) content and leaf mass per area (LMA). This paper describes to what extent these allometric relations are robust to changes in soil fertility and the growth irradiance of the plants. Plants of 25 herbaceous species were grown under controlled conditions in factorial combinations of low/high soil fertility and low/high growth irradiance. Net photosynthetic rates per unit dry mass were measured at light intensities ranging from 0 to 700 µmol m(-2) s(-1) photosynthetically active radiation (PAR). The differing growth environments induced large changes in N, LMA and in each of the parameter estimates of the Mitscherlich and Michaelis-Menten functions. However, the differing growth environments induced only small (although significant) changes in the allometric relationships linking N and LMA to the parameters of the two functions. As a result, 88 % (Mitcherlich) and 89 % (Michaelis-Menten) of the observed net photosynthetic rates over the full range of light intensities (0-700 µmol m(-2) s(-1) PAR) and across all four growth environments could be predicted using only N and LMA using the same allometric relations. These results suggest the possibility of predicting net photosynthetic rates in nature across species over the full range of light intensities using readily available data.

  8. Facile synthesis of flake-like TiO2/C nano-composites for photocatalytic H2 evolution under visible-light irradiation

    Science.gov (United States)

    Yan, Baolin; Zhou, Juan; Liang, Xiaoyu; Song, Kainan; Su, Xintai

    2017-01-01

    The production of H2 by photocatalytic water splitting has become a promising approach for clean, economical, and renewable evolution of H2 by using solar energy. In spite of tremendous efforts, the present challenge for materials scientists is to build a highly active photocatalytic system with high efficiency and low cost. Here we report a facile method for the preparation of TiO2/C nano-flakes, which was used as an efficient visible-light photocatalyst for H2 evolution. This composite material was prepared by using a phase-transfer strategy combined with salt-template calcination treatment. The results showed that anatase TiO2 nanoparticles with the diameter of ∼10 nm were uniformly dispersed on the carbon nano-flakes. In addition, the samples prepared at 600 °C (denoted as T600) endowed a larger surface area of 196 m2 g-1 and higher light absorption, resulting in enhanced photocatalytic activity. Further, the T600 product reached a high H2 production rate of 57.2 μmol h-1 under visible-light irradiation. This unusual photocatalytic activity arose from the positive synergetic effect between the TiO2 and carbon in this hybrid catalyst. This work highlights the potential of TiO2/C nano-flakes in the field of photocatalytic H2 evolution under visible-light irradiation.

  9. In situ plasmonic Au nanoparticle anchored nickel ferrite: An efficient plasmonic photocatalyst for fluorescein-sensitized hydrogen evolution under visible light irradiation

    Science.gov (United States)

    Zeng, Jian; Zeng, Wangdong; Zeng, Heping

    2017-09-01

    Photocatalytic hydrogen generation is a considerable promising technology to decrease climate change effect of CO2 and to solve the increasing global demand for clean energy. Hydrogen generation driven by visible light still faces many challenges although great efforts have been made. Efficient charge separation plays an important role in solar-energy conversion by heterojunction photocatalysts. Herein we report that nickel ferrites covered by gold plasmonics form well-defined plasmonic photocatalysts for fluorescein-sensitized hydrogen production under visible-light irradiation with largely enhanced photoactivity due to fast separation of photogenerated electron-hole pairs. The optimal Au/NiFe2O4 plasmonic photocatalysts with AuNP loading of 1.5 wt% shows the hydrogen production rate of 0.256 mmol g-1 h-1via localized surface plasmon resonance effect of AuNPs. Fluorescein was acted as photosensitizer to extend the visible-light absorption of Au/NiFe2O4 plasmonic photocatalysts and enhance photocatalytic hydrogen generation efficiency under visible-light irradiation. The optimum rate for hydrogen generation reached 3.162 mmol g-1 h-1 and the rate is about 60-fold and 12-fold higher than that of pure NiFe2O4 and 1.5 wt% Au/NiFe2O4 plasmonic photocatalysts, respectively.

  10. Tuning of the optical properties of In-rich In{sub x}Ga{sub 1−x}N (x=0.82−0.49) alloys by light-ion irradiation at low energy

    Energy Technology Data Exchange (ETDEWEB)

    De Luca, Marta; Polimeni, Antonio; Capizzi, Mario [Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma (Italy); Pettinari, Giorgio [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Ciatto, Gianluca; Fonda, Emiliano [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif sur Yvette Cedex (France); Amidani, Lucia; Boscherini, Federico [Department of Physics and CNISM, University of Bologna, V. le C. Berti Pichat 6/2, 40127 Bologna (Italy); Filippone, Francesco; Bonapasta, Aldo Amore [CNR-Istituto di Struttura della Materia (ISM), Via Salaria Km 29.5, CP 10, I-00016 Monterotondo Stazione (Italy); Knübel, Andreas; Cimalla, Volker; Ambacher, Oliver [Fraunhofer Institute for Applied Solid State Physics, Tullastr. 72, 79108 Freiburg (Germany); Giubertoni, Damiano; Bersani, Massimo [CMM - Fondazione Bruno Kessler, Trieste, via Sommarive 18, 38100, Povo Trento (Italy)

    2013-12-04

    The effects of low-energy irradiation by light ions (H and He) on the properties of In-rich In{sub x}Ga{sub 1−x}N alloys are investigated by optical and structural techniques. H-irradiation gives rise to a remarkable blue-shift of light emission and absorption edge energies. X-ray absorption measurements and first-principle calculations address the microscopic origin of these effects.

  11. Cover Picture: Metastable β-Bi2O3 Nanoparticles with Potential for Photocatalytic Water Purification Using Visible Light Irradiation (ChemistryOpen 4/2013)

    Science.gov (United States)

    2013-01-01

    Cover Picture Maik Schlesinger, Marcus Weber, Steffen Schulze, Michael Hietschold, and Michael Mehring* The cover picture shows the degradation of the model dye rhodamine B (RhB) in water using β-Bi2O3 nanoparticles as photocatalyst, which was prepared from preorganized bismuth oxido clusters. In the background, a homemade photoreactor for in situ studies is shown, including the decolorizing process of the aqueous RhB solution as observed during visible light irradiation. The catalytic cycle shows crucial steps in RhB degradation at the surface of β-Bi2O3 nanoparticles (balls), which can be recycled. After adsorption of RhB at the surface of β-Bi2O3 nanoparticles, the color of the nanoparticles changes from orange to violet. The degradation process (represented by Pac-Man) is induced by irradiation with visible light, resulting in a complete decolorization of the solution as well as the surface of the β-Bi2O3 nanoparticles, indicating a fast de-ethylation process. The latter process is faster than desorption of partially degraded RhB species from the β-Bi2O3 surface, but is demonstrated to occur upon irradiation of RhB-loaded β-Bi2O3 in the solid state. For more details, see the Full Paper by Michael Mehring et al., on p. 146 ff.

  12. Nanocrystalline ZnO doped lanthanide oxide: An efficient photocatalyst for the degradation of malachite green dye under visible light irradiation

    Directory of Open Access Journals (Sweden)

    G.A. Suganya Josephine

    2015-09-01

    Full Text Available Visible light induced semiconductor photocatalysis has received a great attention in recent years due to the contamination of water bodies. In the present study, we have reported the photo catalytic degradation of a toxic organic dye, malachite green using a ZnO doped Dy2O3 photo catalyst under visible light irradiation. The nanocrystalline photocatalyst was prepared by a precipitation method employing the respective nitrates and sodium carbonate as precursors and were characterized by FT-IR, XRD, UV–Vis DRS, FE-SEM and AFM analysis. The experimental results proved that the prepared photo catalysts were crystalline, nanosized and highly active in the visible region. UV–Vis DRS results suggested that the band gap was 3.1 eV for the prepared photo catalyst. The photodegradation efficiency of malachite green was analysed by various experimental parameters namely pH, catalyst dosage, variation of substrate concentration and effect of electrolyte addition. The photo degradation process followed a pseudo first order kinetics and was continuously monitored by UV–Visible spectrophotometer. The degradation of malachite green was above 99% within 1 h of visible light irradiation employing the doped photocatalyst, whereas pristine metal oxide possessed only 67% and pristine lanthanide oxide possessed activity which was only due to photolysis. A plausible mechanism for the generation of OH radicals and the pathway for MG dye degradation has been proposed in this study. The experimental results clearly show that nanocrystalline semiconductor doped lanthanide oxides are highly active under visible light irradiations and may find wider applications in environmental remediation technologies.

  13. Ag@AgCl QDs decorated g-C3N4 nanoplates: The photoinduced charge transfer behavior under visible light and full arc irradiation

    Science.gov (United States)

    Li, Junqi; Hao, Hongjuan; Zhou, Jian; Li, Weijie; Lei, Nan; Guo, Liu

    2017-11-01

    The quantum dots (QDs) Ag@AgCl decorated g-C3N4 nanoplates was synthesized via a facile oil-in-water self-assembly method, which possessed high dispersion by characterization of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The as-obtained Ag@AgCl/g-C3N4 nano-heterostructure contained a wide band gap of AgCl nanoparticles (NPs), the surface plasmon resonance (SPR) of Ag NPs and a narrow band gap of g-C3N4 nanoplates. The AgCl NPs with a wide band gap was excited under UV-light, which played a key role on the photoinduced charge transfer of Ag@AgCl/g-C3N4. Under the visible light irradiation, the electrons transfered to the CB of AgCl (electron acceptor) and the holes lefted in the VB of g-C3N4. Nevertheless, under the full arc irradiation, the electrons and holes stayed in the CB of g-C3N4 and VB of AgCl, respectively, then the AgCl was electron donor. The photoinduced charge transfer behavior of Ag@AgCl/g-C3N4 was verified by the photoelectrochemical measurements under the visible light and the full arc irradiation. The results showed that the difference of charge transfer behavior under visible light and the full arc influences on the photoinduced charge transfer ability, further leading to changing the water redox potential in the Ag@AgCl/g-C3N4 nano-heterostructure

  14. Treatment System for Removing Halogenated Compounds from Contaminated Sources

    Science.gov (United States)

    Quinn, Jacqueline W. (Inventor); Clausen, Christian A. (Inventor); Yestrebsky, Cherie L. (Inventor)

    2015-01-01

    A treatment system and a method for removal of at least one halogenated compound, such as PCBs, found in contaminated systems are provided. The treatment system includes a polymer blanket for receiving at least one non-polar solvent. The halogenated compound permeates into or through a wall of the polymer blanket where it is solubilized with at least one non-polar solvent received by said polymer blanket forming a halogenated solvent mixture. This treatment system and method provides for the in situ removal of halogenated compounds from the contaminated system. In one embodiment, the halogenated solvent mixture is subjected to subsequent processes which destroy and/or degrade the halogenated compound.

  15. Photo-alignment of low-molecular mass nematic liquid crystals on photochemically bifunctional chalcone-epoxy film by irradiation of a linearly polarized UV light

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Dong Hoon; Cha, Young Kwan [Kyunghee Univ., Yongin (Korea, Republic of)

    2002-04-01

    Photocrosslinkable chalcone-epoxy compound comprising 1,3-bis-(4-hydroxy-phenyl)-propenone was synthesized for fabricating the photo-alignment layer of liquid crystals. Chalcone group was introduced into the main chain unit of the epoxy oligomer. We observed a photodimerization behavior and an optical anisotropy of this material by irradiation of a linearly polarized UV(LP-UV) light. With a trace amount of cationic photo initiator (TRS-HFA), polymerization of epoxy groups was also conducted at the similar wavelength range used for photodimerization . Linearly polarized UV irradiation on the chalcone-epoxy films with cationic photoinitiator induced optical anisotropy of the film and the resultant film can be used for alignment layers for low molecular weight nematic liquid crystals.

  16. Photo-alignment of low-molecular mass nematic liquid crystals on photochemically bifunctional chalcone-epoxy film by irradiation of a linearly polarized UV light

    CERN Document Server

    Choi, D H

    2002-01-01

    Photocrosslinkable chalcone-epoxy compound comprising 1,3-bis-(4-hydroxy-phenyl)-propenone was synthesized for fabricating the photo-alignment layer of liquid crystals. Chalcone group was introduced into the main chain unit of the epoxy oligomer. We observed a photodimerization behavior and an optical anisotropy of this material by irradiation of a linearly polarized UV(LP-UV) light. With a trace amount of cationic photo initiator (TRS-HFA), polymerization of epoxy groups was also conducted at the similar wavelength range used for photodimerization . Linearly polarized UV irradiation on the chalcone-epoxy films with cationic photoinitiator induced optical anisotropy of the film and the resultant film can be used for alignment layers for low molecular weight nematic liquid crystals.

  17. Lighting

    Data.gov (United States)

    Federal Laboratory Consortium — Lighting Systems Test Facilities aid research that improves the energy efficiency of lighting systems. • Gonio-Photometer: Measures illuminance from each portion of...

  18. Photocatalytic Oxidation of Low-Level Airborne 2-Propanol and Trichloroethylene over Titania Irradiated with Bulb-Type Light-Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Wan-Kuen Jo

    2013-01-01

    Full Text Available This study examined the photocatalytic oxidation of gas-phase trichloroethylene (TCE and 2-propanol, at indoor levels, over titanium dioxide (TiO2 irradiated with light-emitting diodes (LED under different operational conditions. TiO2 powder baked at 450 °C exhibited the highest photocatalytic decomposition efficiency (PDE for TCE, while all photocatalysts baked at different temperatures showed similar PDEs for 2-propanol. The average PDEs of TCE over a three hour period were four, four, five, and 51% for TiO2 powders baked at 150, 250, 350, and 450 °C, respectively. The average PDEs of 2-propanol were 95, 97, 98, and 96% for TiO2 powders baked at 150, 250, 350, and 450 °C, respectively. The ratio of anatase at 2θ = 25.2° to rutile at 2θ = 27.4° was lowest for the TiO2 powder baked at 450 °C. Although the LED-irradiated TiO2 system revealed lower PDEs of TCE and 2-propanol when compared to those of the eight watt, black-light lamp-irradiated TiO2 system, the results for the PDEs normalized to the energy consumption were reversed. Other operational parameters, such as relative humidity, input concentrations, flow rate, and feeding type were also found to influence the photocatalytic performance of the UV LED-irradiated TiO2 system when applied to the cleaning of TCE and 2-propanol at indoor air levels.

  19. Enhanced Hydrogen Production over C-Doped CdO Photocatalyst in Na2S/Na2SO3 Solution under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Quan Gu

    2012-01-01

    Full Text Available The C-doped CdO photocatalysts were simply prepared by high-temperature solid-state process. The as-prepared photocatalysts were characterized by X-ray powder diffraction (XRD, diffuse reflectance spectroscopy (UV-Vis DRS, scanning electron microscopy (SEM and X-ray photoelectron spectroscopy (XPS. The results demonstrated that the carbon was doped into CdO, resulting in the red-shift of the optical absorption of CdO. The photocatalytic behavior of CdO and C-doped CdO was evaluated under the visible light irradiation by using the photocatalytic hydrogen evolution as a model reaction. The C-doped CdO photocatalysts had higher photocatalytic activity over parent CdO under visible light irradiation. The results indicated that the H2 production was due to the existence of CdS and the enhancement of visible light photocatalytic activity of H2 production was originated from the doping of carbon into the CdO lattice. The probably reaction mechanism was also discussed and proposed.

  20. Enhancement of Ischemic Wound Healing by Spheroid Grafting of Human Adipose-Derived Stem Cells Treated with Low-Level Light Irradiation.

    Science.gov (United States)

    Park, In-Su; Chung, Phil-Sang; Ahn, Jin Chul

    2015-01-01

    We investigated whether low-level light irradiation prior to transplantation of adipose-derived stromal cell (ASC) spheroids in an animal skin wound model stimulated angiogenesis and tissue regeneration to improve functional recovery of skin tissue. The spheroid, composed of hASCs, was irradiated with low-level light and expressed angiogenic factors, including vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), and hepatocyte growth factor (HGF). Immunochemical staining analysis revealed that the spheroid of the hASCs was CD31+, KDR+, and CD34+. On the other hand, monolayer-cultured hASCs were negative for these markers. PBS, human adipose tissue-derived stromal cells, and the ASC spheroid were transplanted into a wound bed in athymic mice to evaluate the therapeutic effects of the ASC spheroid in vivo. The ASC spheroid transplanted into the wound bed differentiated into endothelial cells and remained differentiated. The density of vascular formations increased as a result of the angiogenic factors released by the wound bed and enhanced tissue regeneration at the lesion site. These results indicate that the transplantation of the ASC spheroid significantly improved functional recovery relative to both ASC transplantation and PBS treatment. These findings suggest that transplantation of an ASC spheroid treated with low-level light may be an effective form of stem cell therapy for treatment of a wound bed.

  1. Novel chromium doped perovskites A2ZnTiO6 (A = Pr, Gd): Synthesis, crystal structure and photocatalytic activity under simulated solar light irradiation

    Science.gov (United States)

    Zhu, Hekai; Fang, Minghao; Huang, Zhaohui; Liu, Yan'gai; Chen, Kai; Guan, Ming; Tang, Chao; Zhang, Lina; Wang, Meng

    2017-01-01

    Double perovskite related oxides A2ZnTiO6 (A = Pr, Gd) have been successfully synthesized by solid state reaction and investigated as photocatalysts for the first time. The two layered titanates mainly demonstrate absorbances under UV irradiation, except for several sharp absorption bands above 400 nm for Pr2ZnTiO6. Therefore, a series of photocatalysts by doping A2ZnTiO6 (A = Pr, Gd) with Cr have been developed in the hope to improve their absorption in the visible light region. The successful incorporation of Cr was detected by XRD and XPS, and the prepared samples have also been characteriazed by SEM, UV-vis DRS and PL. The characterization results suggested that Cr was present mainly in the form of Cr3+, with only a small amount of Cr6+ species. It served as an efficient dopant for the extension of visible light absorbance and improved photocatalytic activities under solar light irradiation. For both Pr2ZnTiO6 and Gd2ZnTiO6, the valence band (VB) was composed of hybridized states of the Zn 3d, O 2p and the conduction band (CB) has major contribution from Zn 4s, Ti 3d orbitals. For Cr doped samples, the newly formed spin-polarized valence band in the middle of the band gap that primarily arises from Cr 3d orbitals was responsible for the improved optical and photocatalytic properties.

  2. Halogen-bonding-triggered supramolecular gel formation

    Science.gov (United States)

    Meazza, Lorenzo; Foster, Jonathan A.; Fucke, Katharina; Metrangolo, Pierangelo; Resnati, Giuseppe; Steed, Jonathan W.

    2013-01-01

    Supramolecular gels are topical soft materials involving the reversible formation of fibrous aggregates using non-covalent interactions. There is significant interest in controlling the properties of such materials by the formation of multicomponent systems, which exhibit non-additive properties emerging from interaction of the components. The use of hydrogen bonding to assemble supramolecular gels in organic solvents is well established. In contrast, the use of halogen bonding to trigger supramolecular gel formation in a two-component gel (‘co-gel’) is essentially unexplored, and forms the basis for this study. Here, we show that halogen bonding between a pyridyl substituent in a bis(pyridyl urea) and 1,4-diiodotetrafluorobenzene brings about gelation, even in polar media such as aqueous methanol and aqueous dimethylsulfoxide. This demonstrates that halogen bonding is sufficiently strong to interfere with competing gel-inhibitory interactions and create a ‘tipping point’ in gel assembly. Using this concept, we have prepared a halogen bond donor bis(urea) gelator that forms co-gels with halogen bond acceptors.

  3. Light

    DEFF Research Database (Denmark)

    Prescott, N.B.; Kristensen, Helle Halkjær; Wathes, C.M.

    2004-01-01

    This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality......This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality...

  4. Gd, I-doped TiO2 thin films coated on solid waste material: synthesis, characterization, and photocatalytic activity under UV or visible light irradiation

    Science.gov (United States)

    Deng, Siwei; Yu, Jiang; Yang, Chun; Chang, Jiahua; Wang, Yizheng; Wang, Ping; Xie, Shiqian

    2017-10-01

    In this work, titanium dioxide thin films doped with different concentrations of gadolinium (Gd) and iodine (I) were synthesized using the sol-gel method and successfully coated on solid waste material (made in our lab) by dipping, resulting in the titanium dioxide thin-film-coated material (TiO2M). Then, the doped titanium dioxide thin films were characterized by X-ray diffraction (XRD), SEM, and UV-Vis spectroscopy; the optimum coating cycle was evaluated by removal rates of COD and ammonia nitrogen in raw wastewater and secondary effluent. Moreover, the photocatalytic activity was determined by degradation efficiency of methyl orange. The results showed that TiO2M had desirable reusability and the photocatalytic activity was attractive under ultraviolet light irradiation. Furthermore, it is found that the amount of dopant in TiO2 was a key parameter in increasing the photoactivity. 1% Gd-doped TiO2M exhibited the best photocatalytic activity for the degradation of methyl orange with the removal rate reaching 85.55%. The result was in good agreement with the observed smaller crystallite size and profitable crystal structure (anatase phase). Besides, the TiO2M (0.8% Gd-doped TiO2M, 1% Gd-doped TiO2M, 10% I-doped TiO2M, and 5% I-1% Gd-doped TiO2M) with desirable photocatalytic activity at ultraviolet light irradiation was selected for the visible light photocatalytic experiments with taking methyl orange as the target pollutants. The results showed that all of them exhibited the similar photocatalytic activity after 7 h of sunlight irradiation (around 90% removal effect). In general, this research developed a very effective and environmentally friendly photocatalyst for pollutant degradation.

  5. Initiation of apoptosis by photodynamic therapy using a novel positively charged and water-soluble near infra-red photosensitizer and white light irradiation.

    Science.gov (United States)

    Schastak, S; Yafai, Y; Geyer, W; Kostenich, G; Orenstein, A; Wiedemann, P

    2008-01-01

    Our aim was to investigate the photophysical and photodynamic properties of a new, water-soluble positively charged and chemically stable photosensitizer: tetrahydroporphyrin tetratosylat (THPTS). Absorption, fluorescence and (1)H NMR spectra and the intracellular distribution of THPTS were measured. The apoptosis in choroidal melanoma cells was measured using cell death detection ELISA and caspase-8 activity assay. THPTS-PDT efficiency was studied in Balb/c mice bearing C26 colon carcinoma. Subcutaneously located tumors were irradiated with a white light source at a fluence rate of 100 mW/cm(2). THPTS was administrated 3 h before illumination. The tumoricidal effect was examined 24 h after THPTS-PDT by vital staining with 0.4-ml 1% Evans blue solution, intraperitoneally injected to each mouse. THPTS showed a strong absorption band at 760 nm. Its purity, measured by (1)H NMR, is better than 99%. At 24-h incubation period, CLSM revealed THPTS fluorescence in mitochondria and cell nucleus. THPTS possesses no toxic effect in preincubated CM cells without irradiation, and THPTS-PDT causes efficient apoptosis. THPTS-PDT using white light irradiation at a dose of 480 J/cm(2) caused necrosis with a depth of 8 mm in subcutaneously located C26 colon carcinoma in Balb/c-mice. In accordance with the present results, the THPTS seems to be of interest for further in vivo investigations with broad-band white light sources. (c) 2008 Prous Science, S.A.U. or its licensors. All rights reserved.

  6. Facile synthesis of flake-like TiO{sub 2}/C nano-composites for photocatalytic H{sub 2} evolution under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Baolin; Zhou, Juan; Liang, Xiaoyu; Song, Kainan; Su, Xintai, E-mail: suxintai827@163.com

    2017-01-15

    Highlights: • TiO{sub 2}/C nano-flakes were prepared by a facile phase-transfer strategy combined with salt-template calcination method. • The sub–10 nm of TiO{sub 2} NPs were uniformly dispersed on the carbon flakes. • The TiO{sub 2}/C nano-flakes showed a superior visible-light photocatalytic activity for H{sub 2} production. - Abstract: The production of H{sub 2} by photocatalytic water splitting has become a promising approach for clean, economical, and renewable evolution of H{sub 2} by using solar energy. In spite of tremendous efforts, the present challenge for materials scientists is to build a highly active photocatalytic system with high efficiency and low cost. Here we report a facile method for the preparation of TiO{sub 2}/C nano-flakes, which was used as an efficient visible-light photocatalyst for H{sub 2} evolution. This composite material was prepared by using a phase-transfer strategy combined with salt-template calcination treatment. The results showed that anatase TiO{sub 2} nanoparticles with the diameter of ∼10 nm were uniformly dispersed on the carbon nano-flakes. In addition, the samples prepared at 600 °C (denoted as T600) endowed a larger surface area of 196 m{sup 2} g{sup −1} and higher light absorption, resulting in enhanced photocatalytic activity. Further, the T600 product reached a high H{sub 2} production rate of 57.2 μmol h{sup −1} under visible-light irradiation. This unusual photocatalytic activity arose from the positive synergetic effect between the TiO{sub 2} and carbon in this hybrid catalyst. This work highlights the potential of TiO{sub 2}/C nano-flakes in the field of photocatalytic H{sub 2} evolution under visible-light irradiation.

  7. TiO2 supported gold nanoparticles: An efficient photocatalyst for oxidation of alcohol to aldehyde and ketone in presence of visible light irradiation

    Science.gov (United States)

    Gogoi, Nibedita; Borah, Geetika; Gogoi, Pradip K.; Chetia, Tridip Ranjan

    2018-01-01

    An efficient heterogeneous photocatalyst composed of Au nanoparticle supported on TiO2 (anatase) is prepared by sol-gel method. This prepared nanocomposite showed good catalytic activity in the oxidation of various alcohols to aldehyde and ketone under irradiation of visible light. Various spectroscopic techniques including UV-Visible absorption spectral studies and photoluminescence study are employed to characterize the catalyst. It was also characterized by XRD, TEM, BET, XPS and ICP-AES analysis. In contrast to air and H2O2, use of TBHP as oxidant gave good yield. The reaction conditions with respect to solvent and amount of catalyst are optimized.

  8. Optical anisotropy of polyimide and polymethacrylate containing photocrosslinkable chalcone group in the side chain under irradiation of a linearly polarized UV light

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Dong Hoon; Cha, Young Kwan [Kyunghee Univ., Yongin (Korea, Republic of)

    2002-03-01

    Photocrosslinkable soluble polyimide and polymethacrylate compound were synthesized for studying the optically induced anisotropy of the thin films. Chalcone group was introduced into the side chain unit of two polymers. We observed a photodimerization behavior between the double bonds in the chalcone group and an optical anisotropy of these materials by irradiation of a linearly polarized UV light (LPL). Optical anisotropy of the thin film was also investigated by using polarized UV absorption spectroscopy.The dynamic property of optical anisotropy in photoreactive polyimide was compared to that in polymethacrylate containing chalcone group in the side chain.

  9. Multistimuli responsive organogels based on a new gelator featuring tetrathiafulvalene and azobenzene groups: reversible tuning of the gel-sol transition by redox reactions and light irradiation.

    Science.gov (United States)

    Wang, Cheng; Chen, Qun; Sun, Fei; Zhang, Deqing; Zhang, Guanxin; Huang, Yanyan; Zhao, Rui; Zhu, Daoben

    2010-03-10

    For the development of multistimuli responsive organogels, the new organic gelator LMWG 1, featuring electroactive TTF and photoresponsive azobenzene groups, was designed and studied. By manipulating the redox state of the TTF group in LMWG 1, the gel-sol transition for organogels with the LMWG 1 can be reversibly tuned by either chemical or electrochemical oxidation/reduction reactions. Alternatively, the photoisomerization of the azobenzene group in LMWG 1 can also trigger the gel-sol transition. Therefore, organogels with LMWG 1 respond not only to thermal stimuli but also to redox reactions and light irradiation.

  10. Novel RGO/α-FeOOH supported catalyst for Fenton oxidation of phenol at a wide pH range using solar-light-driven irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ying, E-mail: yingwang@bnu.edu.cn [The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875 (China); Fang, Jiasheng, E-mail: fangfangcanfly@163.com [The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875 (China); School of Chemistry and Chemical Engineering, Southeast University, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, Nanjing 211189 (China); Crittenden, John C., E-mail: John.Crittenden@ce.gatech.edu [School of Civil and Environmental Engineering and the Brook Byers Institute for Sustainable Systems, Georgia Institute of Technology, Atlanta, GA 30332-0595 (United States); Shen, Chanchan [The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875 (China)

    2017-05-05

    Graphical abstract: Schematic of the preparation of RF supported catalysts and the reaction mechanism for SLD Fenton catalytic degradation of aqueous phenol. - Highlights: • Novel SLD Fenton catalyst was synthesized via in-situ induced self-assembly process. • RGO improved light-harvesting capacity and enhanced electro-transport performance. • Visible light irradiation accelerated reaction and extended operating pHs (4.0–8.0). • H{sub 2}O{sub 2} reduction and H{sub 2}O oxidation yielded ·OH in Fe{sup Ⅱ}/Fe{sup Ⅲ} and Fe{sup Ⅲ}/Fe{sup Ⅳ} cycling process. - Abstract: A novel solar-light-driven (SLD) Fenton catalyst was developed by reducing the ferrous-ion onto graphene oxide (GO) and forming reduced graphene oxide/α-FeOOH composites (RF) via in-situ induced self-assembly process. The RF was supported on several mesoporous supports (i.e., Al-MCM-41, MCM-41 and γ-Al{sub 2}O{sub 3}). The activity, stability and energy use for phenol oxidation were systematically studied for a wide pH range. Furthermore, the catalytic mechanism at acid and alkaline aqueous conditions was also elucidated. The results showed that Fe(II) was reduced onto GO nanosheets and α-FeOOH crystals were formed during the self-assembly process. Compared with Fenton reaction without SLD irradiation, the visible light irradiation not only dramatically accelerated the rate of Fenton-based reactions, but also extended the operating pH for the Fenton reaction (from 4.0 to 8.0). The phenol oxidation on RF supported catalysts was fitting well with the pseudo-first-order kinetics, and needed low initiating energy, insensitive to the reacting temperature changes (273–318 K). The Al-MCM-41 supported RF was a more highly energy-efficient catalyst with the prominent catalytic activity at wide operating pHs. During the reaction, ·OH radicals were generated by the SLD irradiation from H{sub 2}O{sub 2} reduction and H{sub 2}O oxidation in the Fe{sup Ⅱ}/Fe{sup Ⅲ} and Fe{sup Ⅲ}/Fe{sup

  11. Enhanced photocatalytic performance of BiVO{sub 4} in aqueous AgNO{sub 3} solution under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chien-Kai [Department of Chemistry, National Changhua University of Education, Changhua City, Taiwan (China); Wu, Tsunghsueh [Department of Chemistry, University of Wisconsin-Platteville, Platteville (United States); Huang, Chang-Wei [Department of Chemistry, National Changhua University of Education, Changhua City, Taiwan (China); Lai, Chi-Yung [Department of Biology, National Changhua University of Education, Changhua, Taiwan (China); Wu, Mei-Yao, E-mail: meiyaowu0919@gmail.com [Research Centre for Traditional Chinese Medicine, Department of Medical Research, China Medical University Hospital, Taichung City, Taiwan (China); Lin, Yang-Wei, E-mail: linywjerry@cc.ncue.edu.tw [Department of Chemistry, National Changhua University of Education, Changhua City, Taiwan (China)

    2017-03-31

    Graphical abstract: Ag{sup +} ions enhanced photocatalytic activity of BiVO{sub 4} under visible light irradiation. - Highlights: • The presence of Ag{sup +} ions enhanced the photodegradation activity of BiVO{sub 4}. • Photoreduction of Ag deposited on the BiVO{sub 4} surface was obtained. • Luminescence and electrochemical results elucidated the photocatalytic mechanism. • Holes and oxygen radicals were the main reactive species generated by BiVO{sub 4}/Ag{sup +}. • Used BiVO{sub 4}/Ag{sup +} exhibited photocatalytic antibacterial activity toward E. coli. - Abstract: Monoclinic-phase bismuth vanadate (BiVO{sub 4}) with a 2.468 eV band gap exhibited enhanced synergic photodegradation activity toward methylene blue (MB) when combined with silver ions (Ag{sup +}) in an aqueous solution under visible light irradiation. The mass ratio of AgNO{sub 3} to BiVO{sub 4} and the calcination temperature were discovered to considerably affect the degradation activity of BiVO{sub 4}/Ag{sup +}. Superior photocatalytic performance was obtained when BiVO{sub 4} was mixed with 0.01%(w/v) AgNO{sub 3} solution, and complete degradation of MB was achieved after 25 min visible light irradiation, outperforming BiVO{sub 4} or AgNO{sub 3} solution alone. The enhanced photodegradation was investigated using systematic luminescence measurements, electrochemical impedance spectroscopy, and scavenger addition, after which a photocatalytic mechanism for MB degradation under visible light irradiation was identified that involved oxygen radicals and holes. This study also discovered the two dominating processes involved in enhancing the electron–hole separation efficiency and reducing their recombination rate, namely photoreduction of Ag{sup +} and the formation of a BiVO{sub 4}/Ag heterojunction. The synergic effect between BiVO{sub 4} and Ag{sup +} was discovered to be unique. BiVO{sub 4}/Ag{sup +} was successfully used to degrade two other dyes and disinfect Escherichia Coli. A

  12. Optical anisotropy of polyimide and polymethacrylate containing photocrosslinkable chalcone group in the side chain under irradiation of a linearly polarized UV light

    CERN Document Server

    Choi, D H

    2002-01-01

    Photocrosslinkable soluble polyimide and polymethacrylate compound were synthesized for studying the optically induced anisotropy of the thin films. Chalcone group was introduced into the side chain unit of two polymers. We observed a photodimerization behavior between the double bonds in the chalcone group and an optical anisotropy of these materials by irradiation of a linearly polarized UV light (LPL). Optical anisotropy of the thin film was also investigated by using polarized UV absorption spectroscopy.The dynamic property of optical anisotropy in photoreactive polyimide was compared to that in polymethacrylate containing chalcone group in the side chain.

  13. Electroreductive Remediation of Halogenated Environmental Pollutants.

    Science.gov (United States)

    Martin, Erin T; McGuire, Caitlyn M; Mubarak, Mohammad S; Peters, Dennis G

    2016-12-28

    Electrochemical reduction of halogenated organic compounds is gaining increasing attention as a strategy for the remediation of environmental pollutants. We begin this review by discussing key components (cells, electrodes, solvents, and electrolytes) in the design of a procedure for degrading a targeted pollutant, and we describe and contrast some experimental techniques used to explore and characterize the electrochemical behavior of that pollutant. Then, we describe how to probe various mechanistic features of the pertinent electrochemistry (including stepwise versus concerted carbon-halogen bond cleavage, identification of reaction intermediates, and elucidation of mechanisms). Knowing this information is vital to the successful development of a remediation procedure. Next, we outline techniques, instrumentation, and cell designs involved in scaling up a benchtop experiment to an industrial-scale system. Finally, the last and major part of this review is directed toward surveying electrochemical studies of various categories of halogenated pollutants (chlorofluorocarbons; disinfection byproducts; pesticides, fungicides, and bactericides; and flame retardants) and looking forward to future developments.

  14. Evaluation of Halogenated Coumarins for Antimosquito Properties

    Directory of Open Access Journals (Sweden)

    Venugopala K. Narayanaswamy

    2014-01-01

    Full Text Available Mosquitoes are the major vectors of parasites and pathogens affecting humans and domestic animals. The widespread development of insecticide resistance and negative environmental effects of most synthetic compounds support an interest in finding and developing alternative products against mosquitoes. Natural coumarins and synthetic coumarin analogues are known for their several pharmacological properties, including being insecticidal. In the present study halogenated coumarins (3-mono/dibromo acetyl, 6-halogenated coumarin analogues were screened for larvicidal, adulticidal, and repellent properties against Anopheles arabiensis, a zoophilic mosquito that is one of the dominant vectors of malaria in Africa. Five compounds exerted 100% larval mortality within 24 h of exposure. All coumarins and halogenated coumarins reversibly knocked down adult mosquitoes but did not kill them after 24 h of exposure. Repellent properties could not be evidenced. Five compounds were considered potential larvicidal agents for further research and development, while adulticidal activity was considered only mild to moderate.

  15. Strength, character, and directionality of halogen bonds involving cationic halogen bond donors.

    Science.gov (United States)

    Riley, Kevin E; Tran, Khanh-An

    2017-10-13

    Halogen bonds involving cationic halogen bond donors and anionic halogen bond acceptors have recently been recognized as being important in stabilizing the crystal structures of many salts. Theoretical characterization of these types of interactions, most importantly in terms of their directionality, has been limited. Here we generate high-quality symmetry adapted perturbation theory potential energy curves of a H3N-C[triple bond, length as m-dash]C-Br+Cl- model system in order to characterize halogen bonds involving charged species, in terms of contributions from electrostatics, exchange, induction, and dispersion, with special emphasis on analyzing contributions that are most responsible for the directionality of these interactions. It is found that, as in the case of neutral halogen bonds, exchange forces are important contributors to the directionality of charged halogen bonds, however, it is also found that induction effects, which contribute little to the stability and directionality of neutral halogen bonds, play a large role in the directionality of halogen bonds involving charged species. Potential energy curves based on the ωB97X-D/def2-TZVP/C-PCM method, which includes an implicit solvation model in order to mimic the effects of the crystal medium, are produced for both the H3N-C[triple bond, length as m-dash]C-Br+Cl- model system and for the 4-bromoaniliniumCl- dimer, which is based on the real 4-bromoanilinium chloride salt, whose crystal structure has been determined experimentally. It is found that, within a crystal-like medium, charged halogen bond are significantly weaker than in the gas phase, having optimum interaction energies up to approximately -20 kcal mol-1.

  16. Aqueous secondary formation of brominated, chlorinated, and mixed halogenated pyrene in presence of halide ions.

    Science.gov (United States)

    Sankoda, Kenshi; Toda, Izumi; Sekiguchi, Kazuhiko; Nomiyama, Kei; Shinohara, Ryota

    2017-03-01

    We examined the secondary production of halogenated derivatives of polycyclic aromatic hydrocarbons (PAHs) in surface seawater. Pyrene was selected as the model compound and exposed to UV irradiation in synthetic seawater for various irradiation times. Pyrene underwent rapid photochemical reactions that produced various halogenated derivatives including 1-chloropyrene, 1-bromopyrene, three unidentified dichloropyrenes, and three unidentified bromochloropyrenes. The production of 1-chloropyrene (220-360 nM) was higher than that of 1-bromopyrene (7.3-12 nM), reflecting the high chlorine content of seawater. A pilot field survey was conducted to test the environmental implications of these results, and fresh, brackish, and seawater samples were collected in southwestern Japan. The variation in the concentration ratios between 1-chloropyrene and pyrene implied the presence of a specific source of 1-chloropyrene in coastal water, which can be partly explained by the secondary production observed in our photolysis experiments. In sum, the photochemical reactions of PAHs are a potential secondary source of halogenated PAHs, especially in marine environments heavily contaminated with PAHs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Modification of the silver nanoparticles size-distribution by means of laser light irradiation of their water suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Nikolov, A.S., E-mail: anastas_nklv@yahoo.com [Institute of Electronics, Bulgarian Academy of Sciences, Tsarigradsko Chaussee 72, Sofia 1784 (Bulgaria); Nikov, R.G.; Dimitrov, I.G.; Nedyalkov, N.N.; Atanasov, P.A. [Institute of Electronics, Bulgarian Academy of Sciences, Tsarigradsko Chaussee 72, Sofia 1784 (Bulgaria); Alexandrov, M.T. [Institute of Experimental Pathology and Parasitology, Bulgarian Academy of Sciences, G. Bonchev Street, bl. 25, Sofia 1113 (Bulgaria); Karashanova, D.B. [Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, G. Bonchev Street, bl. 109, Sofia 1113 (Bulgaria)

    2013-09-01

    Contamination-free Ag nanoparticles were produced by nanosecond pulsed laser ablation (10 Hz repetition rate, 15 ns pulse duration) of a solid target immersed in double distilled water. The size distribution observed of the NPs is wider compared to those obtained by other preparation methods, mainly chemical. To modify it and make the NPs more appropriate for biological application, the fabricated suspensions were irradiated by an unfocused laser beam. The fundamental wavelength (λ = 1064 nm) of a Nd:YAG laser system was used for Ag NPs preparation. It lies outside their surface plasmon absorption band and was chosen to avoid self-absorption during ablation by already formed NPs. Excluding a possible absorption in the preparation stage provides a better control of the irradiation influence. The following irradiation of the suspension obtained was performed by the third (λ{sub THG} = 355 nm) harmonic of the laser system, which was chosen due to its positioning within the corresponding surface plasmon absorption band. The changes of the NPs characteristics caused by different laser fluence and duration of irradiation were traced by transmission electron microscopy (TEM) and confirmed by optical transmission measurements in the near UV and the visible region. A considerable narrowing (by about of a factor of three) of the surface plasmon extinction band was achieved, which is evidence of narrowing of the particles size distribution and approach of their shape to the ideal spherical.

  18. Halogen Bonds in Novel Polyhalogen Monoanions.

    Science.gov (United States)

    Wang, Changwei; Danovich, David; Shaik, Sason; Mo, Yirong

    2017-06-27

    Polyhalogen monoanions [X 2n+1 ] - (X=Cl and Br; n=1, 2, 3, 4, and 5) have been systematically studied using the block-localized wave function (BLW) method, which offers a valence bond (VB) analysis. For each species, the most stable isomer can be described as a central halide anion X - non-classically bonded to a number of dihalogen molecules X 2 via "halogen bonds". VB analyses confirm the dominant role of the charge-transfer interaction between the lone pair on X - and the σ-anti-bonding orbital of X 2 molecule (n→σ*) in X 3 - and higher analogues. Thus, our study demonstrates that these halogen bonds are essentially dative covalent interactions. Importantly, the charge-transfer interaction between [X 2n-1 ] - and X 2 decreases with the increasing n, in accord with the weakening of the Lewis basicity as characterized by the corresponding HOMO energy. The reduction of the charge transfer interaction underscores the reduction of covalence in halogen bonds in [X 2n+1 ] - . This tendency highlights the anti-cooperative effect in polyhalogen monoanions. All in all, the halogen bond between X - and nX 2 molecules exhibits the same trends as in X - with a single X 2 molecule. In other words, halogen bonding in the larger clusters derives from the same bonding mechanism as the [X 3 ] - anion. As such, the X - ⋅⋅⋅X 2 halogen bond at different bond lengths forms a gauge of covalence for the entire [X 2n+1 ] - family. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Halogen Chemistry in Volcanic Plumes (Invited)

    Science.gov (United States)

    Roberts, Tjarda

    2017-04-01

    Volcanoes release vast amounts of gases and particles in the atmosphere. Volcanic halogens (HF, HCl, HBr, HI) are co-emitted alongside SO2, and observations show rapid formation of BrO and OClO in the plume as it disperses into the troposphere. The development of 1D and Box models (e.g. PlumeChem) that simulate volcanic plume halogen chemistry aims to characterise how volcanic reactive halogens form and quantify their atmospheric impacts. Following recent advances, these models can broadly reproduce the observed downwind BrO/SO2 ratios using "bromine-explosion" chemistry schemes, provided they use a "high-temperature initialisation" to inject radicals (OH, Cl, Br and possibly NOx) which "kick-start" the low-temperature chemistry cycles that convert HBr into reactive bromine (initially as Br2). The modelled rise in BrO/SO2 and subsequent plateau/decline as the plume disperses downwind reflects cycling between reactive bromine, particularly Br-BrO, and BrO-HOBr-BrONO2. BrCl is produced when aerosol becomes HBr-depleted. Recent model simulations suggest this mechanism for reactive chlorine formation can broadly account for OClO/SO2 reported at Mt Etna. Predicted impacts of volcanic reactive halogen chemistry include the formation of HNO3 from NOx and depletion of ozone. This concurs with HNO3 widely reported in volcanic plumes (although the source of NOx remains under question), as well as observations of ozone depletion reported in plumes from several volcanoes (Mt Redoubt, Mt Etna, Eyjafjallajokull). The plume chemistry can transform mercury into more easily deposited and potentially toxic forms, for which observations are limited. Recent incorporation of volcanic halogen chemistry in a 3D regional model of degassing from Ambrym (Vanuatu) also predicts how halogen chemistry causes depletion of OH to lengthen the SO2 lifetime, and highlights the potential for halogen transport from the troposphere to the stratosphere. However, the model parameter-space is vast and

  20. 40 CFR 721.329 - Halogenated benzyl ester acrylate (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated benzyl ester acrylate... Specific Chemical Substances § 721.329 Halogenated benzyl ester acrylate (generic). (a) Chemical substance... halogenated benzyl ester acrylate (PMN P-90-1527) is subject to reporting under this section for the...

  1. Fabrication of SnO2-Reduced Graphite Oxide Monolayer-Ordered Porous Film Gas Sensor with Tunable Sensitivity through Ultra-Violet Light Irradiation

    Science.gov (United States)

    Xu, Shipu; Sun, Fengqiang; Yang, Shumin; Pan, Zizhao; Long, Jinfeng; Gu, Fenglong

    2015-01-01

    A new graphene-based composite structure, monolayer-ordered macroporous film composed of a layer of orderly arranged macropores, was reported. As an example, SnO2-reduced graphite oxide monolayer-ordered macroporous film was fabricated on a ceramic tube substrate under the irradiation of ultra-violet light (UV), by taking the latex microsphere two-dimensional colloid crystal as a template. Graphite oxide sheets dispersed in SnSO4 aqueous solution exhibited excellent affinity with template microspheres and were in situ incorporated into the pore walls during UV-induced growth of SnO2. The growing and the as-formed SnO2, just like other photocatalytic semiconductor, could be excited to produce electrons and holes under UV irradiation. Electrons reduced GO and holes adsorbed corresponding negative ions, which changed the properties of the composite film. This film was directly used as gas-sensor and was able to display high sensitivity in detecting ethanol gas. More interestingly, on the basis of SnO2-induced photochemical behaviours, this sensor demonstrated tunable sensitivity when UV irradiation time was controlled during the fabrication process and post in water, respectively. This study provides efficient ways of conducting the in situ fabrication of a semiconductor-reduced graphite oxide film device with uniform surface structure and controllable properties. PMID:25758292

  2. Fabrication of SnO₂-reduced graphite oxide monolayer-ordered porous film gas sensor with tunable sensitivity through ultra-violet light irradiation.

    Science.gov (United States)

    Xu, Shipu; Sun, Fengqiang; Yang, Shumin; Pan, Zizhao; Long, Jinfeng; Gu, Fenglong

    2015-03-11

    A new graphene-based composite structure, monolayer-ordered macroporous film composed of a layer of orderly arranged macropores, was reported. As an example, SnO2-reduced graphite oxide monolayer-ordered macroporous film was fabricated on a ceramic tube substrate under the irradiation of ultra-violet light (UV), by taking the latex microsphere two-dimensional colloid crystal as a template. Graphite oxide sheets dispersed in SnSO4 aqueous solution exhibited excellent affinity with template microspheres and were in situ incorporated into the pore walls during UV-induced growth of SnO2. The growing and the as-formed SnO2, just like other photocatalytic semiconductor, could be excited to produce electrons and holes under UV irradiation. Electrons reduced GO and holes adsorbed corresponding negative ions, which changed the properties of the composite film. This film was directly used as gas-sensor and was able to display high sensitivity in detecting ethanol gas. More interestingly, on the basis of SnO2-induced photochemical behaviours, this sensor demonstrated tunable sensitivity when UV irradiation time was controlled during the fabrication process and post in water, respectively. This study provides efficient ways of conducting the in situ fabrication of a semiconductor-reduced graphite oxide film device with uniform surface structure and controllable properties.

  3. Photoorientation of a liquid-crystalline polyester with azobenzene side groups: Effects of irradiation with linearly polarized red light after photochemical pretreatment

    DEFF Research Database (Denmark)

    Zebger, Ingo; Rutloh, Michael; Hoffmann, Uwe

    2003-01-01

    of this two-step process is the angular-selective transformation of the bulky Z-isomers to the rodlike E-isomeric formed by the red light. The aligned E-azobenzene side groups become strongly J-aggregated. Very high values of dichroism of about 0.8 and birefringence of about 0.3 were generated as a result......-isomer, which destroys any initial orientational order and J-aggregates. The orientation process is cooperative, whereas the light-induced orientation of the photochromic moiety causes an ordering of the alkylene spacers and even of the main-chain segments into the same direction. The most probable mechanism...... of this combination of the photoinduced orientation process and the thermotropic self-organization, which take place simultaneously under the irradiation conditions. The process results in a uniaxial prolate order of the film, whereas conventional photoorientation leads to a biaxial oblate order. These two different...

  4. Optical manipulation of Saccharomyces cerevisiae cells reveals that green light protection against UV irradiation is favored by low Ca2+ and requires intact UPR pathway.

    Science.gov (United States)

    Farcasanu, Ileana C; Mitrica, Radu; Cristache, Ligia; Nicolau, Ioana; Ruta, Lavinia L; Paslaru, Liliana; Comorosan, Sorin

    2013-11-01

    Optical manipulation of Saccharomyces cerevisiae cells with high density green photons conferred protection against the deleterious effects of UV radiation. Combining chemical screening with UV irradiation of yeast cells, it was noted that the high density green photons relied on the presence of intact unfolded protein response (UPR) pathway to exert their protective effect and that the low Ca(2+) conditions boosted the effect. UPR chemical inducers tunicamycin, dithiotreitol and calcium chelators augmented the green light effect in a synergic action against UV-induced damage. Photo-manipulation of cells was a critical factor since the maximum protection was achieved only when cells were pre-exposed to green light. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  5. Oral Decontamination of Orthodontic Patients Using Photodynamic Therapy Mediated by Blue-Light Irradiation and Curcumin Associated with Sodium Dodecyl Sulfate.

    Science.gov (United States)

    Panhóca, Vitor Hugo; Esteban Florez, Fernando Luis; Corrêa, Thaila Quatrini; Paolillo, Fernanda Rossi; de Souza, Clovis Wesley Oliveira; Bagnato, Vanderlei Salvador

    2016-09-01

    The aim of this study was to investigate the effects of the antimicrobial photodynamic therapy (aPDT) using the association of curcumin with the surfactant sodium dodecyl sulfate (SDS) for oral decontamination in orthodontic patients. The installation of the orthodontic appliances promotes an increase in the retentive area that is available for microbial aggregation and makes difficult the oral health promotion. However, aPDT is one possible approach that is used for the reduction of oral microbial load. Twenty-four patients (n = 24) were randomly distributed into four groups: Light group: which was treated only with the blue light, no drug; PDT group, which was treated with curcumin and blue light; PDT + S group, which was treated with curcumin plus surfactant and irradiated with blue light; and Chlorhex group, which was treated with chlorhexidine. The photosensitizer agent was prepared by adding 0.1% of SDS to a curcumin solution of 1 g/L. Two distinct LED devices emitting blue light (450 ± 10 nm) were used as follows: extra-oral irradiation (200 mW, 80 mW/cm(2), 36 J and 14 J/cm(2)) and intra-oral irradiation (1200 mW, 472 mW/cm(2), 216 J and 85 J/cm(2)).The collection of nonstimulated saliva (n = 3; 3 mL/collection) was performed at the following steps: (1) immediately before swishing (curcumin, chlorhexidine, or water); (2) after swishing; and (3) after performing aPDT treatments. The colony-forming units (CFU) were counted visually, and the values were adjusted to CFU/mL. There was significant Log reduction for PDT (from 6.33 ± 0.92 to 5.78 ± 0.96, p PDT + S (from 5.44 ± 0.94 to 3.83 ± 0.71, p PDT + S and Chlorhex groups compared with all situations (p PDT + S and Chlorhex groups (p ≥ 0.05). These results indicate that when associated with the surfactant SDS, the aPDT can be used as an adjutant and a convenient agent to promote the oral decontamination in clinical practice.

  6. Deposition of CdS nanoparticles on MIL-53(Fe) metal-organic framework with enhanced photocatalytic degradation of RhB under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Longxing, E-mail: hulxhhhb@shu.edu.cn [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Deng, Guihua [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Lu, Wencong [College of Sciences, Shanghai University, Shanghai 200444 (China); Pang, Siwei; Hu, Xing [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China)

    2017-07-15

    Graphical abstract: The CdS/MIL-53(Fe) photocatalyst has been synthesized by a facile two-step solvothermal method and applied for photocatalytic degradation of organic pollutant RhB under visible light irradiation. - Highlights: • A novel CdS/MIL-53(Fe) photocatalyst was successfully synthesized via a facile two-step solvothermal method. • CdS/MIL-53(Fe) exhibited an enhanced visible-light photocatalytic degradation of RhB in water. • The mechanisms for the formation of CdS/MIL-53(Fe) and photocatalytic degradation of RhB were proposed. - Abstract: A novel composite, CdS/MIL-53(Fe), was successfully fabricated via a facile solvothermal method and characterized with XRD, SEM, TEM, XPS, FT-IR and UV–vis DRS. The results showed that the fabrication was able to result in a good dispersion of CdS nanoparticles onto MIL-53(Fe). The photocatalytic activities of the as-synthesized composite were investigated through the degradation of Rhodamine B (RhB) in water under visible light irradiation. It was found that the composite prepared at the mass ratio of CdS to MIL-53(Fe) of 1.5:1 displayed the highest photocatalytic activity. An approximately 92.5% of photocatalytic degradation of RhB was achieved at 0.5 g/L of 1.5-CdS/MIL dosage, 10 mg/L of initial RhB concentration and 23 °C of reaction temperature under visible light irradiation. The RhB photocatalytic degradation followed well the first-order kinetics equation and the increased catalyst dosage and optimal initial RhB concentration were responsible for the enhanced photocatalytic degradation. Quenching tests revealed that the predominant free radicals in the CdS/MIL-(53)-RhB{sub aq}-visible light system was O{sub 2}{sup −}·; nevertheless, h{sup +} and ·OH also contributed to a certain degree. The enhanced photocatalytic performance was ascribed to the formation of heterojunction structure between CdS and MIL-53(Fe) which significantly suppressed the recombination of photogenerated electron-hole pairs

  7. Effectiveness and ergonomic features of different light sources for polymerization of composite resin materials.

    Science.gov (United States)

    Filipov, Ivan A; Vladimirov, Stoyan B; Uzunova, Jordanka I; Lukanov, Liudmil K

    2003-01-01

    Besides the halogen curing lights, already accepted as standard equipment, diode and plasma-arc units for polymerization of filling materials have also been commercially available in Bulgaria in recent years. The present study was prompted by the lack of detailed scientific information about these novel light curing devices. 1. To evaluate the quality of polymerization achieved by different light curing units by measuring the quantity of residual monomer in the test specimens. 2. To classify the units according to their convenience features and polymerization abilities. Five diode units from three different manufacturers, one plasma-arc unit and one halogen unit were used. The test specimens, made from the hybrid photopolymerizing material Illumine (Ortho Plus, France), Type II, radiopaque, color C1, were 2 mm high and 4 mm in diameter. They were cured for 40 seconds with the respective unit after which they were ground and 25 mg from each sample were immersed in 8 ml of 95% ethanol for extraction of the residual monomer. The quantity of the residual monomer was determined by the method of the standard straight line. Statistical analysis was performed with the analysis of variance and F-test. The comparisons in each group were made by the Tukey-Kramer test, the level of significance for the null hypothesis being P = 0.05. The complex evaluation of the units was made with the help of a scale, developed by us. The material polymerized by the halogen light demonstrated the smallest quantities of residual monomer of all the specimens. There was no statistically significant difference between the quantities of the residual monomer in the specimens polymerized by the plasma arc unit (PAC), OL2 and Elipar Free Light exp. Such a difference, however, existed when comparing the PAC unit and the 3M ESPE unit, working in a continuous irradiation mode, the former having more residual monomer. Polymerization by Elipar Free Light produced the smallest quantities of residual

  8. Novel chromium doped perovskites A{sub 2}ZnTiO{sub 6} (A = Pr, Gd): Synthesis, crystal structure and photocatalytic activity under simulated solar light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Hekai [Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Fang, Minghao, E-mail: fmh@cugb.edu.cn [Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Huang, Zhaohui, E-mail: huang118@cugb.edu.cn [Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Liu, Yan’gai [Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Chen, Kai [National Engineering Research Center for Rare Earth Materials, General Research Institute For Nonferrous Metals, Grirem Advanced Materials Co.,Ltd., Beijing 100088 (China); Guan, Ming; Tang, Chao; Zhang, Lina; Wang, Meng [Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China)

    2017-01-30

    Highlights: • Novel Cr doped A{sub 2}ZnTiO{sub 6} (A = Pr, Gd) photocatalysts were successfully synthesized. • The light absorbance and photocatalytic activity are enhanced through Cr doping. • The photocatalytic reaction mechanism of these photocatalyst was investigated. - Abstract: Double perovskite related oxides A{sub 2}ZnTiO{sub 6} (A = Pr, Gd) have been successfully synthesized by solid state reaction and investigated as photocatalysts for the first time. The two layered titanates mainly demonstrate absorbances under UV irradiation, except for several sharp absorption bands above 400 nm for Pr{sub 2}ZnTiO{sub 6}. Therefore, a series of photocatalysts by doping A{sub 2}ZnTiO{sub 6} (A = Pr, Gd) with Cr have been developed in the hope to improve their absorption in the visible light region. The successful incorporation of Cr was detected by XRD and XPS, and the prepared samples have also been characteriazed by SEM, UV–vis DRS and PL. The characterization results suggested that Cr was present mainly in the form of Cr3+, with only a small amount of Cr6+ species. It served as an efficient dopant for the extension of visible light absorbance and improved photocatalytic activities under solar light irradiation. For both Pr{sub 2}ZnTiO{sub 6} and Gd{sub 2}ZnTiO{sub 6}, the valence band (VB) was composed of hybridized states of the Zn 3d, O 2p and the conduction band (CB) has major contribution from Zn 4s, Ti 3d orbitals. For Cr doped samples, the newly formed spin-polarized valence band in the middle of the band gap that primarily arises from Cr 3d orbitals was responsible for the improved optical and photocatalytic properties.

  9. Photocatalytic decomposition of acrylonitrile with N-F codoped TiO2/SiO2 under simulant solar light irradiation.

    Science.gov (United States)

    Pang, Dandan; Qiu, Lu; Wang, Yunteng; Zhu, Rongshu; Ouyang, Feng

    2015-07-01

    The solid acid catalyst, N-F codoped TiO2/SiO2 composite oxide was prepared by a sol-gel method using NH4F as nitrogen and fluorine source. The prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-Visible diffuse reflectance spectroscopy (UV-Vis), ammonia adsorption and temperature-programmed desorption (NH3-TPD), in situ Fourier transform infrared spectroscopy (FT-IR) and N2 physical adsorption isotherm. The photocatalytic activity of the catalyst for acrylonitrile degradation was investigated under simulant solar irradiation. The results showed that strong Lewis and Brønsted acid sites appear on the surface of the sample after N-F doping. Systematic investigation showed that the highest photocatalytic activity for acrylonitrile degradation was obtained for samples calcined at 450°C with molar ratio (NH4F to Ti) of 0.8. The degradation ratio of 71.5% was achieved with the prepared catalyst after 6-min irradiation, demonstrating the effectiveness of photocatalytic degradation of acrylonitrile with N-F codoped TiO2/SiO2 composite oxide. The photocatalyst is promising for application under solar light irradiation. Moreover, the intermediates generated after irradiation were verified by gas chromatography-mass spectrometry (GC-MS) analysis and UV-Vis spectroscopy to be simple organic acids with lower toxicity, and the degradation pathway was also proposed for acrylonitrile degradation with the prepared catalyst. Copyright © 2015. Published by Elsevier B.V.

  10. Photoluminescence performance of thulium doped Li{sub 4}SrCa(SiO{sub 4}){sub 2} under irradiation of ultraviolet and vacuum ultraviolet lights

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaofeng [Department of Science Teaching, Gansu University of Traditional Chinese Medicine, Lanzhou 730000 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li, Yezhou, E-mail: leelienzoey@gmail.com [Department of Science Teaching, Gansu University of Traditional Chinese Medicine, Lanzhou 730000 (China); Liu, Xiong; Wei, Xingmin; Chen, Yueling; Zhou, Fei [Department of Science Teaching, Gansu University of Traditional Chinese Medicine, Lanzhou 730000 (China); Wang, Yuhua [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China)

    2014-11-15

    Highlights: • A novel blue-emitting phosphor Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} was reported. • Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} exhibited excellent thermal and irradiation stability. • Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} was found to possess high color purity. - Abstract: In this work, we synthesized Tm{sup 3+} doped Li{sub 4}SrCa(SiO{sub 4}){sub 2} phosphors and investigated their photoluminescence properties under the excitation of ultraviolet and vacuum ultraviolet lights. The crystal structure analysis and variation of cell parameters confirm that Tm{sup 3+} ions have been successfully doped in the structure of Li{sub 4}SrCa(SiO{sub 4}){sub 2} host by occupying the sites of Ca{sup 2+} with the coordination number of 6. The luminescence results suggest that Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} is a good blue-emitting phosphor when excited by ultraviolet and vacuum ultraviolet irradiations. In addition, it is observed that there is nearly no degradation for Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} after undergoing thermal and irradiation treatments. Possible mechanisms for the luminescence processes are proposed on the basis of the discussion of excitation and emission spectra. In particular, the emission color of Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} by excitation of 147 and 172 nm irradiations is very close to the standard blue color, suggesting that it could be potentially applied in plasma display panels and mercury-free fluorescence lamps.

  11. Hydrothermal Synthesis of Hydrangea-Like F-Doped Titania Microspheres for the Photocatalytic Degradation of Carbamazepine under UV and Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Miaomiao Ye

    2012-01-01

    Full Text Available Hydrangea-like F-doped TiO2 microspheres have been synthesized on a large scale by a simple hydrothermal process using potassium titanium oxalate as the titanium source, ammonium fluoride and hydrogen peroxide as the etchant. The photocatalytic activities were evaluated using carbamazepine as the target organic molecule under UV and visible light irradiation. Structural characterization indicates that the hydrangea-like TiO2 microspheres, with an average diameter of 2.80 μm, are composed of numerous anatase TiO2 petals. Moreover, it is found that both the NH4F and H2O2 dosages have important effects on the formation of the hydrangea-like structures. In addition, photocatalytic experiments show that the hydrangea-like TiO2 microspheres calcined at 500°C exhibit high photocatalytic efficiency under both UV and visible light irradiation. The enhanced photocatalytic activity can be attributed to the successful fluorine doping, good crystallinity, and the unique nanostructures.

  12. Mechanism of photoluminescence quenching in thin films of N,N'-bis(3-methylphenyl-N,N'-bis(phenylbenzidine irradiated by UV light in air

    Directory of Open Access Journals (Sweden)

    Tomović Aleksandar Ž.

    2015-01-01

    Full Text Available The mechanism of photoluminescence (PL quenching of thin amorphous N,N'-bis(3-methylphenyl- N,N'-bis(phenylbenzidine (TPD films exposed to UV light in air is studied. TPD is small organic molecule widely used in production of organic light emmiting devices (OLEDs. Photoluminescence of TPD films decays exponentially with time of irradiation, i.e. with the increase of concentration of impurities (photo-oxidized TPD molecules generated by UV irradiation in air. Intensity of PL decreases to half of its original value when the concentration of impurities reaches 0.4%. Average distance between impurities (acceptors is almost an order of magnitude larger than average distance between host TPD molecules (donors. Direct long range Forster energy transfer is ruled out as the mechanism of PL quenching, as the overlap between donor and acceptor is lacking, and exciton self-diffusion in TPD films is postulated for the mechanism. The presence of oxidation products is confirmed by infrared (IR spectroscopy. Vibrational spectra of TPD molecule and few other possible products of photo-oxidation of TPD molecule, obtained by density functional theory, are compared to experimental IR spectra.

  13. Synthesis and photocatalytic performance of reduced graphene oxide-TiO2 nanocomposites for orange II degradation under UV light irradiation.

    Science.gov (United States)

    Li, Tengfei; Wang, Tiecheng; Qu, Guangzhou; Liang, Dongli; Hu, Shibin

    2017-05-01

    To enhance the photocatalytic activity of TiO2, reduced graphene oxide-TiO2 (RGO-TiO2) composites with sandwich-like structure were synthesized using a simple solvothermal method. The morphology, crystalline information, and structural property of the photocatalyst were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier transmission infrared spectroscopy. The photocatalytic performances of the RGO-TiO2 composites were evaluated by the degradation of orange II (AO7) in water under UV light irradiation. The results showed that the RGO-TiO2 composites exhibited much higher photocatalytic activity than TiO2 and that the removal efficiency of AO7 could reach above 95% only after 20 min of UV light irradiation under the optimum condition. The improved photocatalytic activity might be attributed to the improved charge transfer and significant separation of the photoinduced electrons and holes in the presence of a two-dimensional graphene network. The results of recycling experiments show that RGO-TiO2 composites have a high photostability, which is expected in the practical application. Radical trapping experiments indicated that ·OH plays a crucial role in the process of AO7 degradation.

  14. Simultaneous removal of Cr(VI) and phenol contaminants using Z-scheme bismuth oxyiodide/reduced graphene oxide/bismuth sulfide system under visible-light irradiation.

    Science.gov (United States)

    Chen, Acong; Bian, Zhaoyong; Xu, Jie; Xin, Xin; Wang, Hui

    2017-12-01

    An all-solid-state Z-scheme system containing Bi-based semiconductors bismuth oxyiodide (BiOI) and bismuth sulfide (Bi 2 S 3 ) was constructed on reduced graphene oxide (rGO) sheets through an electrostatic self-assembly method to simultaneously remove aqueous Cr(VI) and phenol. In this Z-scheme that mimicked natural photosynthesis, photoinduced electrons in the conduction band (CB) of BiOI were transferred through rGO and reacted with photoinduced holes in the valence band (VB) of Bi 2 S 3 , which significantly increased its photocatalytic activity. The reduction and oxidation reactions were performed on Bi 2 S 3 and BiOI photocatalysts, respectively. Furthermore, complex contaminants of coexisting heavy metal Cr(VI) and organic phenol were treated using the system under visible-light irradiation. Results showed that Cr(VI) reduction and phenol oxidation were achieved efficiently with optimum reductive and oxidative efficiencies up to 73% and 95% under visible-light irradiation, respectively. This work provided a promising method of simultaneously removing heavy metals and organic pollutants by using a Z-scheme system with enhanced photocatalytic activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Adipose-derived stem cell spheroid treated with low-level light irradiation accelerates spontaneous angiogenesis in mouse model of hindlimb ischemia.

    Science.gov (United States)

    Park, In-Su; Chung, Phil-Sang; Ahn, Jin Chul

    2017-09-01

    We investigated whether low-level light irradiation (LLLI) before adipose-derived stromal cells (ASCs) spheroid transplantation improved hind-limb functional recovery by stimulation of angiogenesis. The spheroid, composed of ASCs, was irradiated with low-level light and expressed angiogenic factors, including vascular endothelial growth factor and basic fibroblast growth factor. From immunochemical staining analysis, the spheroid of ASCs included CD31+, KDR+ and CD34+, whereas monolayer-cultured ASCs were negative for these markers. To evaluate the therapeutic effect of the ASC spheroid treated with LLLI in vivo, phosphate-buffered saline, monolayer ASCs, LLLI-monolayer ASCs, spheroid ASCs and LLLI-spheroid ASCs were transplanted into a hind-limb ischemia model. The LLLI-spheroid ASCs transplanted into the hind-limb ischemia differentiated into endothelial cells and remained differentiated. Transplantation of LLLI-spheroid ASCs into the hind-limb ischemia significantly elevated the density of vascular formations through angiogenic factors released by the ASCs and enhanced tissue regeneration at the lesion site. Consistent with these results, the transplantation of LLLI-spheroid ASCs significantly improved functional recovery compared with ASC or spheroid ASC transplantation and PBS treatment. These findings suggest that transplantation of ASC spheroid treated with LLLI may be an effective stem cell therapy for the treatment of hind-limb ischemia and peripheral vascular disease. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  16. Synergistic photocatalysis of Cr(VI) reduction and 4-Chlorophenol degradation over hydroxylated α-Fe2O3 under visible light irradiation.

    Science.gov (United States)

    Wang, Ji-Chao; Ren, Juan; Yao, Hong-Chang; Zhang, Lin; Wang, Jian-She; Zang, Shuang-Quan; Han, Li-Feng; Li, Zhong-Jun

    2016-07-05

    A series of Fe2O3 materials with hydroxyl are synthesized in different monohydric alcohol (C2-C5) solvents by solvothermal method and characterized by XRD, BET, XPS, TG and EA. The amount of hydroxyl is demonstrated to be emerged on the surface of the as-synthesized Fe2O3 particles and their contents are determined to be from 7.99 to 3.74 wt%. The Cr(VI) reduction experiments show that the hydroxyl content of Fe2O3 samples exacts great influence on the photocatalytic activity under visible light irradiation (λ>400 nm) and that the Fe2O3 sample synthesized in n-butyl alcohol exhibits the optimal photocatalytic activity. The synergistic photocatalysis for 4-Chlorophenol (4-CP) degradation and Cr(VI) reduction over above Fe2O3 sample is further investigated. The photocatalytic ratio of Cr(VI) reduction are enhanced from 24.8% to 70.2% while that of 4-CP oxidation are increased from 13.5% to 47.8% after 1 h visible light irradiation. The Fe2O3 sample keeps good degradation rates of mixed pollutants after 9 runs. The active oxygen intermediates O2(-)˙, ˙OH and H2O2 formed in the photoreaction process are discovered by ESR measurement and UV-vis test. The photocatalytic degradation mechanism is proposed accordingly. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. In situ growth of CdS nanoparticles on UiO-66 metal-organic framework octahedrons for enhanced photocatalytic hydrogen production under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jian-Jian; Wang, Rong; Liu, Xin-Ling; Peng, Fu-Min [School of Chemistry and Chemical Engineering and Innovation Lab for Clean Energy & Green Catalysis, Anhui University, Hefei 230601 (China); Li, Chuan-Hao, E-mail: chuanhao.li@yale.edu [School of Chemistry and Chemical Engineering and Innovation Lab for Clean Energy & Green Catalysis, Anhui University, Hefei 230601 (China); Department of Chemical & Environmental Engineering, Yale University, New Haven 06511 (United States); Teng, Fei [Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Yuan, Yu-Peng, E-mail: yupengyuan@ahu.edu.cn [School of Chemistry and Chemical Engineering and Innovation Lab for Clean Energy & Green Catalysis, Anhui University, Hefei 230601 (China); Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044 (China)

    2015-08-15

    Graphical abstract: Enhanced photocatalytic hydrogen generation was achieved though constructing the CdS/UiO-66 MOF hybrids. In addition, the resultant hybrids show excellent photostability for hydrogen generation. - Highlights: • CdS nanoparticles were hydrothermally grown on UiO-66 octahedrons. • The resultant CdS/UiO-66 hybrids show enhanced photocatalytic H{sub 2} generation under visible light irradiation. • CdS/UiO-66 hybrids possess excellent photostability for long-term hydrogen generation. - Abstract: CdS nanoparticles acting as photosensitizer was grown in situ upon UiO-66 metal-organic framework octahedrons through a hydrothermal process. The resultant CdS/UiO-66 hybrid photocatalysts show remarkably active hydrogen evolution under visible light irradiation as compared to CdS and UiO-66 alone. The optimum hybrid with 16 wt% CdS loading shows a hydrogen production rate of 235 μmol h{sup −1}, corresponding to 1.2% quantum efficiency at 420 nm. The improved photocatalytic hydrogen production over hybrid CdS/UiO-66 is ascribed to the efficient interfacial charge transfer from CdS to UiO-66, which effectively suppresses the recombination of photogenerated electron-hole pairs and thereby enhancing the photocatalytic efficiency.

  18. Self-assembly of polyoxometalate-azure A multilayer films and their photocatalytic properties for degradation of methyl orange under visible light irradiation.

    Science.gov (United States)

    You, Yanglijun; Gao, Shuiying; Xu, Bo; Li, Guoliang; Cao, Rong

    2010-10-15

    Multilayer films (PW(12)-AA)(n) (PW(12)=PW(12)O(40)(3-), AA=azure A, n is the number of PW(12)-AA bilayers) were prepared on solid slides via a layer-by-layer (LbL) self-assembly method. The growth of the films was characterized by UV-vis spectra, FTIR spectra, and atomic force microscopy (AFM). The results show that the deposition process is linear and reproducible from layer to layer and the PW(12) is intact during the self-assembly process. AFM images indicate that the film surface is smooth and uniform. Moreover, the photocatalytic property of the films was investigated by the decomposition of methyl orange (MO) under visible light irradiation (lambda>420 nm). The multilayer films show photocatalytic activity for the degradation of MO under visible light irradiation using a xenon lamp and sunlight. The kinetics of the photodecomposition follows the first-order reaction. Copyright 2010 Elsevier Inc. All rights reserved.

  19. One-step synthesis of novel PANI-Fe3O4@ZnO core-shell microspheres: An efficient photocatalyst under visible light irradiation

    Science.gov (United States)

    Zhang, Xiaoyuan; Wu, Jianning; Meng, Guihua; Guo, Xuhong; Liu, Chang; Liu, Zhiyong

    2016-03-01

    For the first time, novel multifunctional superparamagnetic PANI-Fe3O4@ZnO core-shell composite photocatalysts with different PANI: ZnO ratios were synthesized by Pickering emulsion route in one step in the presence of ZnO nanoparticles. PANI-Fe3O4@ZnO core-shell microspheres consist of PANI core which embedded with Fe3O4-OA (oleic acid modified Fe3O4) nanoparticles and tunable ZnO shell thickness. The resulting samples were thoroughly studied by using X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). The catalytic activity of the as-prepared PANI-Fe3O4@ZnO core-shell microspheres is investigated by the degradation of MB under visible light irradiation. As expected, the as prepared PANI-Fe3O4@ZnO photocatalysts exhibit highly enhanced photocatalytic activities in the degradation of MB under visible light irradiation owing to fast separation of photo-generated electron-hole pairs. Significantly, the PANI-Fe3O4@ZnO catalysts can be separated from the reaction media by applying an external magnet, and can be reused for seven cycles without change in stability and degradation efficiency.

  20. Oxidative degradation of different chlorinated phenoxyalkanoic acid herbicides by a hybrid ZrO2 gel-derived catalyst without light irradiation.

    Science.gov (United States)

    Sannino, Filomena; Pernice, Pasquale; Minieri, Luciana; Camandona, Gaia Aurora; Aronne, Antonio; Pirozzi, Domenico

    2015-01-14

    The oxidative degradation of 2-methyl-4-chlorophenoxyacetic acid (MCPA), 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB), 4-chlorophenoxyacetic acid (4-CPA) and 2,4-dichlorophenoxyacetic acid (2,4 D) by ZrO2-acetylacetonate hybrid catalyst (HSGZ) without light irradiation was assessed. The thermal stability of the catalyst was investigated by thermogravimetry, differential thermal analysis, and Fourier transform infrared spectroscopy. For each herbicide, a virtually complete removal in about 3 days without light irradiation at room temperature was achieved. The removal kinetics of the herbicides has been satisfactorily characterized by a double-stage physico-mathematical model, in the hypothesis that a first-order adsorption on HSGZ surface is followed by the herbicide degradation, catalytically driven by HSGZ surface groups. The long-term use of the HSGZ catalyst was assessed by repeated-batch tests. The specific cost for unit-volume removal of herbicide was evaluated by a detailed cost analysis showing that it is comparable with those pertaining to alternative methods.

  1. WS2 as an Effective Noble-Metal Free Cocatalyst Modified TiSi2 for Enhanced Photocatalytic Hydrogen Evolution under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Dongmei Chu

    2016-09-01

    Full Text Available A noble-metal free photocatalyst consisting of WS2 and TiSi2 being used for hydrogen evolution under visible light irradiation, has been successfully prepared by in-situ formation of WS2 on the surface of TiSi2 in a thermal reaction. The obtained samples were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive X-ray spectrometry (EDX, transmission electron microscopy (TEM, and X-ray photoelectron spectroscopy (XPS. The results demonstrate that WS2 moiety has been successfully deposited on the surface of TiSi2 and some kind of chemical bonds, such as Ti-S-W and Si-S-W, might have formed on the interface of the TiSi2 and WS2 components. Optical and photoelectrochemical investigations reveal that WS2/TiSi2 composite possesses lower hydrogen evolution potential and enhanced photogenerated charge separation and transfer efficiency. Under 6 h of visible light (λ > 420 nm irradiation, the total amount of hydrogen evolved from the optimal WS2/TiSi2 catalyst is 596.4 μmol·g−1, which is around 1.5 times higher than that of pure TiSi2 under the same reaction conditions. This study shows a paradigm of developing the effective, scalable and inexpensive system for photocatalytic hydrogen generation.

  2. Photo-electrocatalytic activity of TiO2 nanotubes prepared with two-step anodization and treated under UV light irradiation

    Directory of Open Access Journals (Sweden)

    Mohamad Mohsen Momeni

    2016-01-01

    Full Text Available To improve the photo-catalytic degradation of salicylic acid, we reported the fabrication of ordered TiO2 nanotube arrays by a simple and effective two-step anodization method and then these TiO2 nanotubes treated in a methanol solution under UV light irradiation. The TiO2 nanotubes prepared in the two-step anodization process showed better photo-catalytic activity than TiO2 nanotubes prepared in one-step anodization process. Also, compared with TiO2 nanotubes without the UV pretreatment, the TiO2 nanotubes pretreated in a methanol solution under UV light irradiation exhibited significant enhancements in both photocurrent and activity. The treated TiO2 nanotubes exhibited a 5-fold enhancement in photocurrent and a 2.5-fold increase in the photo-catalytic degradation of salicylic acid. Also the effect of addition of persulfate and periodate on the photo-catalytic degradation of salicylic acid were investigated. The results showed that the degradation efficiency of salicylic acid increased with increasing persulfate and periodate concentrations. These treated TiO2 nanotubes are promising candidates for practical photochemical reactors.

  3. Highly Enhanced Photoreductive Degradation of Polybromodiphenyl Ethers with g-C3N4/TiO2 under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Weidong Ye

    2017-04-01

    Full Text Available A series of high activity photocatalysts g-C3N4-TiO2 were synthesized by simple one-pot thermal transformation method and characterized by transmission electron microscopy (TEM, scanning electron microscopy (SEM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller (BET surface area, and ultraviolet–visible diffuse reflectance spectroscopy (UV-Vis-DRS. The g-C3N4-TiO2 samples show highly improved photoreductive capability for the degradation of polybromodiphenyl ethers compared with g-C3N4 under visible light irradiation. Among all the hybrids, 0.02-C3N4-TiO2 with 2 wt % g-C3N4 loaded shows the highest reaction rate, which is 15 times as high as that in bare g-C3N4. The well-matched band gaps in heterojunction g-C3N4-TiO2 not only strengthen the absorption intensity, but also show more effective charge carrier separation, which results in the highly enhanced photoreductive performance under visible light irradiation. The trapping experiments show that holetrapping agents largely affect the reaction rate. The rate of electron accumulation in the conductive band is the rate-determining step in the degradation reaction. A possible photoreductive mechanism has been proposed.

  4. Adsorption and photocatalytic degradation of pharmaceuticals and pesticides by carbon doped-TiO2 coated on zeolites under solar light irradiation.

    Science.gov (United States)

    An, Ye; de Ridder, David Johannes; Zhao, Chun; Schoutteten, Klaas; Bussche, Julie Vanden; Zheng, Huaili; Chen, Gang; Vanhaecke, Lynn

    2016-01-01

    To evaluate the performance of zeolite-supported carbon-doped TiO(2) composite catalysts toward target pollutants under solar light irradiation, the adsorption and photocatalytic degradation of 18 pharmaceuticals and pesticides with distinguishing features (molecular size and volume, and photolysis) were investigated using mordenite zeolites with SiO(2)/Al(2)O(3) ratios of 18 and 240. Different quantities of carbon-doped TiO(2) were coated on the zeolites, and then the finished composite catalysts were tested in demineralized, surface, and hospital wastewater samples, respectively. The composite photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, and surface area and porosity analyses. Results showed that a dispersed layer of carbon-doped TiO(2) is formed on the zeolite surface; this layer blocks the micropores of zeolites and reduces their surface area. However, these reductions did not significantly affect adsorption onto the zeolites. Our results demonstrated that zeolite-supported carbon-doped TiO(2) systems can effectively degrade 18 pharmaceuticals and pesticides in demineralized water under natural and simulated solar light irradiation. In surface and hospital wastewaters, zeolite-supported carbon-doped TiO(2) systems present excellent anti-interference capability against radical scavengers and competitive organics for pollutants removal, and higher pollutants adsorption on zeolites evidently enhances the removal rate of target pollutants in surface and hospital wastewater samples with a complicated matrix.

  5. Damage and polymerization of C sub 6 sub 0 films irradiated by fast light and heavy ions

    CERN Document Server

    Yogo, A; Itoh, A

    2002-01-01

    C sub 6 sub 0 films have been irradiated with various fast ions (H, Li, C, O and Si) in the energy range from 0.75 to 6.0 MeV. Structural changes of C sub 6 sub 0 molecules were studied by a time-of-flight (TOF) mass spectrometry and Raman spectroscopy. The TOF yields of secondary fullerene ions can be described fairly well by S sub m sub o sub d sup 3 with a modified energy deposition S sub m sub o sub d developed in this work. In the Raman study for 1 MeV H sup + irradiation, it is found that about 40% polymerization is attained at 6x10 sup 1 sup 5 cm sup - sup 2 doses and a damage cross-section of 2.5x10 sup - sup 1 sup 7 cm sup 2 is obtained.

  6. Halogenated indole alkaloids from marine invertebrates.

    Science.gov (United States)

    Pauletti, Patrícia Mendonça; Cintra, Lucas Silva; Braguine, Caio Guedes; da Silva Filho, Ademar Alves; Silva, Márcio Luís Andrade E; Cunha, Wilson Roberto; Januário, Ana Helena

    2010-04-28

    This review discusses the isolation, structural elucidation, and biological activities of halogenated indole alkaloids obtained from marine invertebrates. Meridianins and related compounds (variolins, psammopemmins, and aplicyanins), as well as aplysinopsins and leptoclinidamines, are focused on. A compilation of the (13)C-NMR spectral data of these selected natural indole alkaloids is also provided.

  7. Efficient photocatalytic degradation of organic pollutants by magnetically recoverable nitrogen-doped TiO2 nanocomposite photocatalysts under visible light irradiation.

    Science.gov (United States)

    Hamzezadeh-Nakhjavani, Sahar; Tavakoli, Omid; Akhlaghi, Seyed Parham; Salehi, Zeinab; Esmailnejad-Ahranjani, Parvaneh; Arpanaei, Ayyoob

    2015-12-01

    Preparation of novel nanocomposite particles (NCPs) with high visible-light-driven photocatalytic activity and possessing recovery potential after advanced oxidation process (AOP) is much desired. In this study, pure anatase phase titania (TiO2) nanoparticles (NPs) as well as three types of NCPs including nitrogen-doped titania (TiO2-N), titania-coated magnetic silica (Fe3O4 cluster@SiO2@TiO2 (FST)), and a novel magnetically recoverable TiO2 nanocomposite photocatalyst containing nitrogen element (Fe3O4 cluster@SiO2@TiO2-N (FST-N)) were successfully synthesized via a sol-gel process. The photocatalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM) with an energy-dispersive X-ray (EDX) spectroscopy analysis, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), and vibrating sample magnetometer (VSM). The photocatalytic activity of as-prepared samples was further investigated and compared with each other by degradation of phenol, as a model for the organic pollutants, in deionized (DI) water under visible light irradiation. The TiO2-N (55 ± 1.5%) and FST-N (46 ± 1.5%) samples exhibited efficient photocatalytic activity in terms of phenol degradation under visible light irradiation, while undoped samples were almost inactive under same operating conditions. Moreover, the effects of key operational parameters, the optimum sample calcination temperature, and reusability of FST-N NCPs were evaluated. Under optimum conditions (calcination temperature of 400 °C and near-neutral reaction medium), the obtained results revealed efficient degradation of phenol for FST-N NCPs under visible light irradiation (46 ± 1.5%), high yield magnetic separation and efficient reusability of FST-N NCPs (88.88% of its initial value) over 10 times reuse.

  8. Adaptation to high light irradiances enhances the photosynthetic Cu2+ resistance in Cu2+ tolerant and non-tolerant populations of the brown macroalgae Fucus serratus.

    Science.gov (United States)

    Nielsen, Hanne Dalsgaard; Nielsen, Søren Laurentius

    2010-05-01

    The relationship between light acclimation and Cu(2+) tolerance was studied in two populations of Fucus serratus known to be naturally non-tolerant and tolerant to Cu(2+). Acclimation to high irradiances increased the photosynthetic tolerance to Cu(2+). The xanthophyll cycle was apparently not involved in protecting the photosynthetic apparatus against Cu(2+) toxicity, as results showed that Cu(2+) did not induce dynamic photoinhibition. The higher photosynthetic Cu(2+) resistance of high light algae did not result in increased growth. The excess energy acquired by high light-adapted algae appeared to be utilized in Cu(2+) defense mechanisms in the Cu(2+) non-tolerant population. The polyphenol content of the algae was reciprocal to the Cu(T) content, suggesting that polyphenol may be the primary Cu(2+) defense of non-tolerant low light algae, acting through secretion and extracellular chelating of Cu(2+), while the compounds do not seem to be involved in the primary Cu(2+) tolerance mechanism in Cu(2+) tolerant algae. (c) 2009 Elsevier Ltd. All rights reserved.

  9. Photocatalytic and Escherichia antibacterial activities of Ag-TiO2-SiO2 nanocomposite powder under simulated solar light irradiation

    Science.gov (United States)

    Van Dang, Han; Le, Vien Minh; Hoang, Hoang Anh

    2017-09-01

    The photocatalytic nanocomposite powder TiO2, TiO2-SiO2 and Ag-TiO2-SiO2 (ATS) were synthesized by sol-gel method assisted with hydrothermal treatment and characterized by X-ray diffraction (XRD), Raman spectroscopy (RAMAN), Fourier transformed infrared spectroscopy (FT-IR), Energy dispersive X-ray (EDX), Transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET) surface area and UV-Vis absorption spectra analysis. The Escherichia coli (E. coli) antibacterial activity of synthesized photo-catalysts under simulated solar light have been also investigated. The heterogeneous A4TS10 with the 4 wt.% Ag and 10 wt.% SiO2 had anatase and rutile phase, spherical in shape with the particle size about 20 - 30 nm, specific surface area (SSA) of 218.4 m2/g, the band gap of 3.06 eV. The E. coli antibacterial activities of the synthesized samples under simulated solar light were also investigated under simulated solar light with 25 W of light intensity. The E. coli antibacterial ability of A4TS10 performed the highest photo-activity. E. coli bacteria was entirely killed after 30-minute irradiation and no bacterial regrowth was observed after 24 hours. The research results demonstrated that the photocatalytic A4TS10 is a promising green material to treatment wastewater infected bacteria application.

  10. Noble gases and halogens in Graves Nunataks 06129: The complex thermal history of a felsic asteroid crust

    Science.gov (United States)

    Claydon, Jennifer L.; Crowther, Sarah A.; Fernandes, Vera A.; Gilmour, Jamie D.

    2015-06-01

    The meteorite Graves Nunataks 06128/06129 is a rare example of felsic asteroidal crust. Knowledge of its history can help shed light on the evolution processes of planetesimals. The noble gases can be used to constrain both the chronology of meteorites and the processes that result in movements of volatile elements on asteroidal bodies. We have examined the I-Xe and Ar-Ar systems of the plagioclase-rich achondrite, Graves Nunataks 06129 by high-resolution laser step-heating of irradiated samples. Iodine and 129Xe∗ are both present but are released at different temperatures and do not show a correlation, therefore the I-Xe system in GRA 06129 has no chronological significance. We propose that radiogenic 129Xe∗ was lost from primary phases and parentless 129Xe∗ was later introduced into the rock by interaction with a fluid sourced from a reservoir that evolved with a high I/Xe ratio. This could have been the same halogen-rich fluid that induced the conversion of merrillite and pyroxene into chlorapatite. Inherited 40Ar (i.e. not generated by in situ decay of 40K) is also present in one of three fragments studied here and may have been introduced at the same time as parentless 129Xe∗.

  11. Synthesis and characterization of novel Sm2O3/S-doped g-C3N4 nanocomposites with enhanced photocatalytic activities under visible light irradiation

    Science.gov (United States)

    Jourshabani, Milad; Shariatinia, Zahra; Badiei, Alireza

    2018-01-01

    Novel Sm2O3/S-doped g-C3N4 (CNS) composites were synthesized with in situ method by simultaneous combining S doping in carbon nitride structure to produce CNS as well as hybridization of CNS with the Sm2O3 semiconductor. The obtained composite photocatalysts with different Sm2O3 contents were characterized by XRD, FT-IR, XPS, TEM, BET, DRS and PL techniques and their photocatalytic activities were investigated for the degradation of methylene blue (MB) as a model pollutant in aqueous solution under visible-light irradiation. The XRD structure phase and TEM morphology results showed that stacking degree of π-conjugated system in the CNS structure was disrupted in the precense of Sm2O3 particles. The optimal Sm2O3 loading value was determined to be 8.9 wt% and its corresponding MB photodegradation rate was about 93% after 150 min light irradiation, which was indeed greater compared with those of the individual CNS and Sm2O3 samples. This enhanced photocatalytic performance was originated from characteristics of the hybrid formed between the Sm2O3 and CNS so that it improved the effective charge transfer through interfacial interactions between both components. In addition, the CNS synthesized by S doping exhibited a significant enhancement in the photocatalytic activity relative to that of the pure g-C3N4; this was mostly caused by the increase in its visible light harvesting ability and charge mobility. The possible mechanism for the photocatalytic degradation of MB was suggested and discussed in detail based on the findings acquired from radical/hole trapping experiments.

  12. Enhanced photocatalytic activity and characterization of magnetic Ag/BiOI/ZnFe2O4 composites for Hg0 removal under fluorescent light irradiation

    Science.gov (United States)

    Li, Chengwei; Zhang, Anchao; Zhang, Lixiang; Song, Jun; Su, Sheng; Sun, Zhijun; Xiang, Jun

    2018-03-01

    A series of magnetic Ag/BiOI/ZnFe2O4 hybrids synthesized via hydrothermal process, subsequent deposition-precipitation and photoreduction method were employed to remove elemental mercury (Hg0) under fluorescent light irradiation. The effects of Ag content, fluorescent light irradiation, reaction temperature, pH value, flue gas composition, anions and photocatalyst dosage on Hg0 removal were investigated in detail. The as-synthesized photocatalysts were characterized using N2 adsorption-desorption, XRD, SEM, TEM, HRTEM, XPS, VSM, DRS, ESR, PL and photocurrent response. The results showed that the ternary Ag/BiOI/ZnFe2O4 hybrids possessed enhanced visible-light-responsive photocatalytic performances for Hg0 removal. Ag/BiOI/ZnFe2O4 photocatalyst could be easily recovered from the reaction solution by an extra magnet and was stable in the process of Hg0 removal. Lower content of Ag was highly dispersed on the surface of BiOI/ZnFe2O4, while higher content of Ag would result in some aggregations and/or the blockages of micropore. In comparison to BiOI/ZnFe2O4, Ag deposited BiOI/ZnFe2O4 material showed lower recombination rate of electron-hole pairs. The superior Hg0 oxidation removal could correspond to good match of BiOI and ZnFe2O4, excellent fluidity and surface plasmon resonance effect of Ag0 nanoparticles, which led to higher separation efficiency of photogenerated electrons and holes, thereby enhancing the hybrids' photocatalytic activity.

  13. Deposition of CdS nanoparticles on MIL-53(Fe) metal-organic framework with enhanced photocatalytic degradation of RhB under visible light irradiation

    Science.gov (United States)

    Hu, Longxing; Deng, Guihua; Lu, Wencong; Pang, Siwei; Hu, Xing

    2017-07-01

    A novel composite, CdS/MIL-53(Fe), was successfully fabricated via a facile solvothermal method and characterized with XRD, SEM, TEM, XPS, FT-IR and UV-vis DRS. The results showed that the fabrication was able to result in a good dispersion of CdS nanoparticles onto MIL-53(Fe). The photocatalytic activities of the as-synthesized composite were investigated through the degradation of Rhodamine B (RhB) in water under visible light irradiation. It was found that the composite prepared at the mass ratio of CdS to MIL-53(Fe) of 1.5:1 displayed the highest photocatalytic activity. An approximately 92.5% of photocatalytic degradation of RhB was achieved at 0.5 g/L of 1.5-CdS/MIL dosage, 10 mg/L of initial RhB concentration and 23 °C of reaction temperature under visible light irradiation. The RhB photocatalytic degradation followed well the first-order kinetics equation and the increased catalyst dosage and optimal initial RhB concentration were responsible for the enhanced photocatalytic degradation. Quenching tests revealed that the predominant free radicals in the CdS/MIL-(53)-RhBaq-visible light system was O2-rad ; nevertheless, h+ and rad OH also contributed to a certain degree. The enhanced photocatalytic performance was ascribed to the formation of heterojunction structure between CdS and MIL-53(Fe) which significantly suppressed the recombination of photogenerated electron-hole pairs. Moreover, the reusability of 1.5-CdS/MIL composite was also studied.

  14. Synthesis and characterization of Fullerene modified ZnAlTi-LDO in photo-degradation of Bisphenol A under simulated visible light irradiation.

    Science.gov (United States)

    Ju, Liting; Wu, Pingxiao; Lai, Xiaolin; Yang, Shanshan; Gong, Beini; Chen, Meiqing; Zhu, Nengwu

    2017-09-01

    In this study, ZnAlTi layered double hydroxide (ZnAlTi-LDH) combined with fullerene (C60) was fabricated by the urea method, and calcined under vacuum atmosphere to obtain nanocomposites of C60-modified ZnAlTi layered double oxide (ZnAlTi-LDO). The morphology, structure and composition of the nanocomposites were analyzed by Scanning Electron Microscopy, High-resolution transmission electron microscopy, X-ray diffraction patterns, Fourier transform infrared and specific surface area. The UV-vis diffuse reflectance spectra indicated that the incorporation of C60 expanded the absorption of ZnAlTi-LDO to visible-light region. The photo-degradation experiment was conducted by using a series of C60 modified ZnAlTi-LDO with different C60 weight percentage to degrade Bisphenol A (BPA) under simulated visible light irradiation. In this experiment, the degradation rate of C60 modified ZnAlTi-LDO in photo-degradation of BPA under simulated visible light irradiation was over 80%. The intermediates formed in the degradation of BPA process by using LDO/C60-5% were 4-hydroxyphenyl-2-propanol, 4-isopropenylphenol and Phenol. Photogenerated holes, superoxide radical species, ·OH and singlet oxygen were considered to be responsible for the photodegradation process, among which superoxide radical species and ·OH played a predominant role in the photocatalytic reaction system. C60 modified ZnAlTi-LDO catalysts for photocatalytic reduction shows great potential in degradation of organic pollutants and environmental remediation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Influence of different light-curing units on the surface roughness of restorative materials: in situ study

    Directory of Open Access Journals (Sweden)

    Juliane Cristina Ciccone-Nogueira

    2007-09-01

    Full Text Available The aim of this study was to evaluate the influence of different light sources (LED and Halogen lamp on the roughness (superficial of composite resin (Filtek Z250, Filtek P60, Charisma and Durafill varying post-irradiation times, in an in situ experiment. For this purpose, 80 specimens were made in polyurethane moulds. Ten volunteers without medicament use and good oral condition were selected and from them study moulds were obtained. A palatal intra-oral acrylic resin appliance was made for each of the subjects of the experiment. In each appliance, two specimens of each material were fixed (LED/Halogen lamp - control group. Roughness tests were performed immediately and 30 days after initial light-curing. Statistical analysis was performed using ANOVA. Statistically significant difference was observed only between post-irradiation times, where the 30th day showed the highest roughness values. It be concluded that roughness was influenced only by post-irradiation times, presenting the 30- days period inferior behavior.

  16. An overview of the radiation environment at the LHC in light of R2E irradiation test activities

    CERN Document Server

    Roeed, K; Spiezia, G; CERN. Geneva. ATS Department

    2011-01-01

    The main objective of this report is to present a brief overview of the radiation environment that can be expected in areas where electronics is installed in the LHC. This covers particle energy spectra in addition to nominal integrated values of the High Energy Hadron (HEH) fluence, relevant for Single Event Effects (SEEs), Total Ionizing Dose (TID), and the 1 MeV neutron equivalent, relevant for displacement damage. The risk of thermal neutrons is considered by introducing the risk factor Rth. This report is presented as part of the R2E project and should create a foundation from which appropriate irradiation test criteria can be evaluated and determined.

  17. Influence of ageing on Raman spectra and the conductivity of monolayer graphene samples irradiated by heavy and light ions

    Energy Technology Data Exchange (ETDEWEB)

    Butenko, A.; Zion, E.; Richter, V.; Sharoni, A. [Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 52900 (Israel); Kaganovskii, Yu.; Wolfson, L.; Kogan, E.; Kaveh, M.; Shlimak, I. [Department of Physics, Jack and Pearl Resnick Institute, Bar-Ilan University, Ramat Gan 52900 (Israel)

    2016-07-28

    The influence of long-term ageing (about one year) on the Raman scattering (RS) spectra and the temperature dependence of conductivity has been studied in two series of monolayer graphene samples irradiated by different doses of C{sup +} and Xe{sup +} ions. It is shown that the main result of ageing consists of changes in the intensity and position of D- and G- and 2D-lines in RS spectra and in an increase of the conductivity. The observed effects are explained in terms of an increase of the radius of the “activated” area around structural defects.

  18. Photocatalytic Water Splitting for Hydrogen Production with Novel Y2MSbO7 (M = Ga, In, Gd under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Jianhui Chen

    2012-11-01

    Full Text Available Novel photocatalysts Y2MSbO7 (M = Ga, In, Gd were synthesized by the solid state reaction method for the first time. A comparative study on the structural and photocatalytic properties of Y2MSbO7 (M = Ga, In, Gd was reported. The results showed that Y2GaSbO7, Y2InSbO7 and Y2GdSbO7 crystallized with the pyrochlore-type structure, cubic crystal system, and space group Fd3m. The lattice parameter for Y2GaSbO7 was 10.17981 Å. The lattice parameter for Y2InSbO7 was 10.43213 Å. The lattice parameter for Y2GdSbO7 was 10.50704 Å. The band gap of Y2GaSbO7 was estimated to be 2.245 eV. The band gap of Y2InSbO7 was 2.618 eV. The band gap of Y2GdSbO7 was 2.437 eV. For the photocatalytic water-splitting reaction, H2 or O2 evolution was observed from pure water with Y2GaSbO7, Y2InSbO7 or Y2GdSbO7 as catalyst under visible light irradiation. (Wavelength > 420 nm. Furthermore, H2 and O2 were also evolved by using Y2GaSbO7, Y2InSbO7 or Y2GdSbO7 as a catalyst from CH3OH/H2O and AgNO3/H2O solutions, respectively, under visible light irradiation (λ > 420 nm. Y2GaSbO7 showed the highest activity compared with Y2InSbO7 or Y2GdSbO7. At the same time, Y2InSbO7 showed higher activity compared with Y2GdSbO7. The photocatalytic activities were further improved under visible light irradiation with Y2GaSbO7, Y2InSbO7 or Y2GdSbO7 being loaded by Pt, NiO or RuO2. The effect of Pt was better than that of NiO or RuO2 for improving the photocatalytic activity of Y2GaSbO7, Y2InSbO7 or Y2GdSbO7.

  19. Preparation of CdS@CeO{sub 2} core/shell composite for photocatalytic reduction of CO{sub 2} under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ijaz, Sana [CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190 (China); Institute of Chemical Sciences, Bahauddin Zakaryia University, Multan 60800 (Pakistan); Ehsan, Muhammad Fahad [CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190 (China); Ashiq, Muhammad Naeem, E-mail: naeemashiqqau@yahoo.com [Institute of Chemical Sciences, Bahauddin Zakaryia University, Multan 60800 (Pakistan); Karamat, Nazia [Institute of Chemical Sciences, Bahauddin Zakaryia University, Multan 60800 (Pakistan); He, Tao, E-mail: het@nanoctr.cn [CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2016-12-30

    Highlights: • CdS@CeO{sub 2}core(*)/shell composite is fabricated using a two-step method. • CdS@CeO{sub 2} can photoreduce CO{sub 2} into CH{sub 4} and CH{sub 3}OH under visible-light irradiation. • CdS@CeO{sub 2} can enhance photocatalytic activity due to increased charge separation. • Core shell strategy for photocatalyst preparation can improve photostability. - Abstract: Present work demonstrates fabrication of CdS@CeO{sub 2} core/shell composite and its application in the photocatalytic reduction of CO{sub 2} under visible-light irradiation (λ ≥ 420 nm). CdS@CeO{sub 2} composite has been successfully prepared by two-step chemical method, while CeO{sub 2} and CdS have been synthesized by one-step hydrothermal method. X-ray diffraction analysis confirms the formation of fluorite cubic structure of CeO{sub 2} and cubic phase of CdS. High resolution transmission electron microscopy and scanning electron microscopy reveal the microsphere morphology of CdS, while CeO{sub 2} (shell) is in the form of spherical particles that surround the CdS (core) in case of the composite. X-ray photoelectron spectroscopy has been used to confirm the composition, oxidation state of the elements and valance band of the obtained materials. The CdS@CeO{sub 2} core/shell composite and CdS can convert CO{sub 2} into methane and methanol under visible-light irradiation. The CdS@CeO{sub 2} composite shows higher yield for both methane and methanol than CdS due to low recombination rate of photogenerated electron/hole pairs, as well as a larger BET specific surface area. Moreover, the CdS@CeO{sub 2} core/shell composite also shows improved stability upon photocatalysis.

  20. EPR study of the production of OH radicals in aqueous solutions of uranium irradiated by ultraviolet light

    Directory of Open Access Journals (Sweden)

    MARKO DAKOVIĆ

    2009-06-01

    Full Text Available The aim of the study was to establish whether hydroxyl radicals (•OH were produced in UV-irradiated aqueous solutions of uranyl salts. The production of •OH was studied in uranyl acetate and nitrate solutions by an EPR spin trap method over a wide pH range, with variation of the uranium concentrations. The production of •OH in uranyl solutions irradiated with UV was unequivocally demonstrated for the first time using the EPR spin-trapping method. The production of •OH can be connected to speciation of uranium species in aqueous solutions, showing a complex dependence on the solution pH. When compared with the results of radiative de-excitation of excited uranyl (*UO22+ by the quenching of its fluorescence, the present results indicate that the generation of hydroxyl radicals plays a major role in the fluorescence decay of *UO22+. The role of the presence of carbonates and counter ions pertinent to environmental conditions in biological systems on the production of hydroxyl radicals was also assessed in an attempt to reveal the mechanism of *UO22+ de-excitation. Various mechanisms, including •OH production, are inferred but the main point is that the generation of •OH in uranium containing solutions must be considered when assessing uranium toxicity.

  1. Plasmon-induced photoelectrochemical biosensor for in situ real-time measurement of biotin-streptavidin binding kinetics under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jingchun; Oshikiri, Tomoya; Ueno, Kosei; Shi, Xu [Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0021 (Japan); Misawa, Hiroaki, E-mail: misawa@es.hokudai.ac.jp [Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0021 (Japan); Department of Applied Chemistry & Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan (China)

    2017-03-08

    We developed a localized surface plasmon-induced visible light-responsive photoelectrochemical (PEC) biosensor using a titanium dioxide (TiO{sub 2}) photoelectrode loaded with gold nanoislands (AuNIs) for in situ real-time measurement of biotin-streptavidin association. As a proof of concept, self-assembled thiol-terminated biotin molecules bound on a AuNIs/TiO{sub 2} photoelectrode were successfully utilized to explore the photocurrent response to streptavidin-modified gold nanoparticle (STA-AuNP) solutions. This plasmon-induced PEC biosensor is simple and easy to miniaturize. Additionally, the PEC biosensor achieves highly sensitive measurements under only visible light irradiation and prevents the UV-induced damage of samples. Furthermore, a novel approach has been proposed to realize the real-time monitoring of biotin-STA binding affinities and kinetics by analyzing the PEC sensing characteristics. This PEC biosensor and novel analysis method could provide a new approach for the specific electrical detection and real-time kinetic measurements for clinical diagnostics and drug development. - Highlights: • A plasmon-induced visible light-responsive photoelectrochemical biosensor is developed and the system can be miniaturized.

  2. Plasmonic Ag-pillared rectorite as catalyst for degradation of 2,4-DCP in the H2O2-containing system under visible light irradiation.

    Science.gov (United States)

    Chen, Yunfang; Fang, Jianzhang; Lu, Shaoyou; Wu, Yan; Chen, Dazhi; Huang, Liyan; Cheng, Cong; Ren, Lu; Zhu, Ximiao; Fang, Zhanqiang

    2015-10-30

    This study aims at photocatalytic degradation of 2,4-DCP with the assistance of H2O2 in aqueous solution by a composite catalyst of Ag-rectorite. The catalysts were prepared via a novel thermal decomposition method followed after the cation-exchange process. The synthesized nano-materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface analyzer, Ultraviolet-visible light (UV-vis) absorption spectra, field-emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The different mechanisms of degradation process with or without visible light irradiation were discussed, respectively. Moreover, the degradation efficiency of 2,4-DCP wastewater under Ag-rectorite/H2O2/visible light system was investigated by series of experiments, concerning on effects of major operation factors, such as H2O2 dosage and the initial pH value. The highest degradation rate was observed when adding 0.18 mL H2O2 into 50 mL 2,4-DCP solution, and the optimal pH value was 4 for the reaction. Afterwards, total organic carbon (TOC) experiments were carried out to evaluate the mineralization ratio of 2,4-DCP. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. H2 Production Under Visible Light Irradiation from Aqueous Methanol Solution on CaTiO3:Cu Prepared by Spray Pyrolysis

    Science.gov (United States)

    Lim, Sung Nam; Song, Shin Ae; Jeong, Yong-Cheol; Kang, Hyun Woo; Park, Seung Bin; Kim, Ki Young

    2017-10-01

    Perovskite-type photocatalysts of CaCu x Ti1- x O3 (0 ≤ x ≤ 0.02) powder were prepared by spray pyrolysis of aqueous solution or aqueous solution with polymeric additive. The effects of the amount of copper ions doped in the photocatalyst and the precursor type on the photocatalytic activity under visible-light irradiation were investigated. The crystal structure, oxidation state, and light adsorption properties of the prepared photocatalysts were analyzed using x-ray diffraction, x-ray photoelectron spectroscopy, and diffuse reflectance spectroscopy, respectively. The doping of copper ions in CaTiO3 allowed visible-light absorption owing to a narrowing of the band gap energy of the host material through the formation of a new donor level for copper ions. Among the doped samples prepared from the aqueous precursor, CaTiO3 doped with 1 mol.% copper ions had the highest hydrogen evolution rate (140.7 μmol g-1 h-1). Notably, the hydrogen evolution rate of the photocatalyst doped with 1 mol.% copper ions prepared from the aqueous precursor with polymeric additive (295.0 μmol g-1 h-1) was two times greater than that prepared from the aqueous precursor, due to the morphology effect.

  4. Synthesize and characterize of Ag{sub 3}VO{sub 4}/TiO{sub 2} nanorods photocatalysts and its photocatalytic activity under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Xuejun [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian 116600 (China); Dong, Yuying, E-mail: dongy@dlnu.edu.cn [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian 116600 (China); Zhang, Xiaodong, E-mail: fatzhxd@126.com [Environment and Low-Carbon Research Center, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093 (China); Cui, Yubo [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian 116600 (China)

    2016-03-15

    Graphical abstract: - Highlights: • Ag{sub 3}VO{sub 4}/TiO{sub 2} nanorods were prepared by sol–gel with hydrothermal method. • Toluene removal efficiency was 70% in 4 h using the Ag{sub 3}VO{sub 4}/TiO{sub 2}. • Benzyl alcohol and benzaldehyde were intermediates, and partially mineralized. - Abstract: In this paper, in order to expand the light response range of TiO{sub 2}, Ag{sub 3}VO{sub 4}/TiO{sub 2} nanorods photocatalysts were fabricated by a simple sol–gel method with microwave and hydrothermal method. The as-prepared samples were characterized by XRD, SEM, DRS, XPS and N{sub 2} adsorption–desorption. Meanwhile, their photocatalytic properties were investigated by the degradation of toluene under visible light irradiation. The degradation conversation of toluene had gotten to about 70% in 1% Ag{sub 3}VO{sub 4}/TiO{sub 2} nanorods after reaction 4 h. The predominant photocatalytic activity can be attributed to its strong absorption in visible light region and excellent charge separation characteristics. By using in situ FTIR, benzyl alcohol and benzaldehyde species could be observed during the reaction and the formed intermediates would be partially oxidized into CO{sub 2} and H{sub 2}O. Electron spin resonance confirmed that OH· and O{sub 2}·{sup −} were involved in the photocatalytic degradation of toluene.

  5. Light

    CERN Document Server

    Robertson, William C

    2003-01-01

    Why is left right and right left in the mirror? Baffled by the basics of reflection and refraction? Wondering just how the eye works? If you have trouble teaching concepts about light that you don t fully grasp yourself, get help from a book that s both scientifically accurate and entertaining with Light. By combining clear explanations, clever drawings, and activities that use easy-to-find materials, this book covers what science teachers and parents need to know to teach about light with confidence. It uses ray, wave, and particle models of light to explain the basics of reflection and refraction, optical instruments, polarization of light, and interference and diffraction. There s also an entire chapter on how the eye works. Each chapter ends with a Summary and Applications section that reinforces concepts with everyday examples. Whether you need a deeper understanding of how light bends or a good explanation of why the sky is blue, you ll find Light more illuminating and accessible than a college textbook...

  6. Preparation of High Activity Ga and Cu Doped ZnS by Hydrothermal Method for Hydrogen Production under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Melody Kimi

    2015-01-01

    Full Text Available Ga(0.1,Cu(x-ZnS (x=0.01, 0.03, 0.05 photocatalysts were successfully synthesized by hydrothermal method. The synthesized Ga and Cu codoped ZnS photocatalysts showed photocatalytic property effective for hydrogen production from aqueous solution containing Na2SO3 and Na2S as sacrificial reagent under visible light irradiation. The rate of hydrogen production was found to be strongly dependent on Cu doping content. The highest photocatalytic activity is observed for Ga(0.1,Cu(0.01-ZnS with hydrogen production rate of 114 µmol/h. The addition of Ga as codoped increased the photocatalytic activity to 58 times as compared to single doped Cu-ZnS. The Ga and Cu codoped ZnS photocatalysts are also stable under long irradiation. The enhancement in the photocatalytic activity of Ga and Cu codoped photocatalyst can be attributed to the synergistic effect between Ga and Cu. The photocatalytic activity was greatly enhanced with the addition of 0.5 wt% Ru as cocatalyst with a hydrogen production rate of 744 µmol/h.

  7. SYNTHESIS OF POLYANILINE/ZNO (PANI/ZNO NANOCOMPOSITE USING INTERFACE POLYMERIZATION METHOD AND ITS PHOTODEGRADATION TEST ON RHODAMINE B UNDER VISIBLE LIGHT IRRADIATION

    Directory of Open Access Journals (Sweden)

    Muhamad Wisnu Nugroho

    2015-11-01

    Full Text Available Synthesis of polyaniline/ZnO (PANI/ZNO nanocomposite using interface polymerization method as well as its photodegradation test on Rhodamin B dye under visible light irradiation has been performed. Emeraldine salt of PANI and nanocomposite PANI/ZnO can be synthesized using interfacial polymerization method of organic/water biphasic. The characterization of electron transition and functional groups were performed using UV-Vis and FT-IR spectroscopy, respectively. DRS characterization showed that PANI, PANI/ZnO 5% and 10% has energy value of ~ 2.0 eV band gap. SEM analysis with image-J software showed a decrease particle size due to the increasing content of ZnO. Determination of molecular weight polymer using Ostwald viscosimeter showed that the molecular weight PANI is 2835.03 g/mol. The photodegradation test performed using tungsten lamp irradiation for 240 minutes gave result to rhodamine B concentration reduction of 67.9% 85.09% and 80.24% for polyaniline, polyaniline/ZnO 5% and polyaniline/ZnO 10%, respectively.

  8. Antimicrobial photodynamic treatment of gram-negative bacteria with a cationic phenothiazine dye under pulsed light irradiation

    Science.gov (United States)

    Kawauchi, Satoko; Sato, Shunichi; Yamaguchi, Toru; Shinomiya, Nariyoshi; Saito, Daizo; Ashida, Hiroshi; Obara, Minoru; Kikuchi, Makoto

    2005-08-01

    In-vitro photodynamic inactivation of Ps. aeruginosa with methylene blue under pulsed light excitation was investigated at different pulse repetition rates. Bacterial suspensions were illuminated with 670-nm nanosecond pulsed light with a peak intensity of 2.0 MW/cm2 at pulse repetition rates in the range of 5-30 Hz. Photobactericidal effect increased with increasing pulse repetition rate for the same total light dose; more than two orders in magnitude reduction of bacterial survival fraction was obtained at 30 Hz. Such a positive dependence of photobactericidal effect on pulse repetition rate was inconsistent with our previous results for human lung cancer cells that were photodynamically treated with a lysosomal sensitizer. The reason for the increased photobactericidal effect at the high pulse repetition rate is discussed.

  9. Host cell reactivation of ultraviolet light irradiated adenovirus 5 in fibroblasts from patients with Cockayne syndrome. A study with six Japanese cases

    Energy Technology Data Exchange (ETDEWEB)

    Watatani, Masahiro; Ohtani, Hideaki; Takai, Shin-ichiro; Ikenaga, Mituo (Osaka Univ. (Japan). Faculty of Medicine)

    1984-06-01

    Host cell reactivation of plaque-forming ability of ultraviolet light (UV)-irradiated adenovirus 5 was compared between skin fibroblasts derived from 6 unrelated patients with Cockayne syndrome (CS) and those from normal donors. UV survivals of adenovirus were determined with two different virus stocks, one prepared by infecting to HeLa cells and the other prepared from hamster BHK cells. For both of these virus stocks UV survival curves obtained using CS cells showed two components with an initial sensitive portion followed by a component having almost normal sensitivity. This made a marked contrast to the single-hit inactivation curves obtained with normal cells. Consequently, at low UV dose ranges, CS cells were 2 - 3 times less able to reactivate the UV-inactivated adenovirus than normal cells. These results further support our hypothesis that CS cells may be partially defective in excision repair of damaged DNA.

  10. Self-assembly of polyoxometalate-thionine multilayer films on magnetic microspheres as photocatalyst for methyl orange degradation under visible light irradiation.

    Science.gov (United States)

    Li, Hongfang; Gao, Shuiying; Cao, Minna; Cao, Rong

    2013-03-15

    (PW(12)-TH)(n) multilayer films (PW(12)=PW(12)O(40)(3-), TH=thionine) were deposited successfully on core-shell structured Fe(3)O(4)@SiO(2) magnetic microspheres through layer-by-layer (LbL) self-assembly method. The physical and photocatalytic properties of such magnetic microspheres coated with (PW(12)-TH)(n) films have been characterized by SEM, FTIR, and UV-vis spectra. The microspheres exhibit better photocatalytic activity toward the degradation of methyl orange (MO) under visible light irradiation than the quartz slides support. In addition, the use of magnetic support guarantees facile, clean, fast, and efficient separation of the photocatalyst after the degradation of MO. Such catalysts can be reused several times and display good reproducibility by magnetic separation. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Monolayer alignment on azobenzene surfaces during UV light irradiation: analysis of optical polarized absorption measurement results and theoretical treatment.

    Science.gov (United States)

    Zakharov, A V; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2006-01-14

    The influence of the charge separation during the trans-cis conformational change on the surface of azobenzene 6Az10PVA monolayer on the polar liquid-crystal monolayer film, such as 4-n-pentyl-4'-cyanobiphenyl(5CB), is investigated. The effective anchoring energy (in the Rapini-Papolar form) is phenomenologically described in the framework of the molecular model, which takes into account the interaction between the surface polarization and surface electric field, for number of conformational states of the boundary surface. It is shown, using the experimental data for the voltage across the 6Az10PVA+5CB film, provided by the surface-potential technique, that the charge separation during the conformational changing, caused by the UV irradiation, may lead to changing of the surface alignment of liquid-crystalline molecules. The influence of the photoisomerization process on the orientational order parameter S2(t) using the optical polarized absorption measurement is also investigated.

  12. Red Light Combined with Blue Light Irradiation Regulates Proliferation and Apoptosis in Skin Keratinocytes in Combination with Low Concentrations of Curcumin

    OpenAIRE

    Tianhui Niu; Yan Tian; Qing Cai; Qu Ren; Lizhao Wei

    2015-01-01

    Curcumin is a widely known natural phytochemical from plant Curcuma longa. In recent years, curcumin has received increasing attention because of its capability to induce apoptosis and inhibit cell proliferation as well as its anti-inflammatory properties in different cancer cells. However, the therapeutic benefits of curcumin are severely hampered due to its particularly low absorption via trans-dermal or oral bioavailability. Phototherapy with visible light is gaining more and more support ...

  13. A new human photosensitive subject with a defect in the recovery of DNA synthesis after ultraviolet-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Y.; Ichihashi, M.; Kano, Y.; Goto, K.; Shimizu, K.

    1981-09-01

    A non-sensitive, 8-yr-old male patient (termed UV81KO) with only acute recurrent sunburns and without any other physical or neuromental retardations was studied. The patient's skin exhibited lowered minimal erythema doses between 280 and 300 nm monochromatic wavelengths without delayed peaking of erythema. UV81KO skin fibroblasts in culture was 5-fold more sensitive to 254 nm UV killing than normal cells, though the response of obligatory heterozygotes was normal. UV81KO cells were also more sensitive to killings by fluorescent sunlamp (295-300 nm UV-B) radiation, 4-nitroquinoline-1-oxide, and N-hydroxy-acetyl aminofluorene, but not by monofunctional decarbamoyl mitomycin C, bifunctional mitomycin C, and alkylating agents (methyl methanesulfonate, ethyl methanesulfonate, N-methyl-N-nitrosourea). Assays for unscheduled DNA synthesis, T4 endonuclease V-susceptible sites (pyrimidine dimers), endogenous excision-break accumulation by arabinofuranosyl cytosine-plus-hydroxyurea, single-strand-break rejoining, and molecular-weight increase of pulse-chased DNA in irradiated cells indicated no apparently detectable defects in nucleotide-excision repair processes and in replicative bypass in UV81KO cells. Despite the repair proficiency as such, UV81KO cells showed the defective recovery of DNA synthesis after 254 nm UV irradiation with 1 and 5 J/m2, at which dose the recovery occurred in normal cells. The base line level of sister-chromatid exchanges (SCEs) was higher in UV81KO cells (10-12 SCEs/cell) than in normal cells (5 SCEs/cell), although the induction rate of SCEs by 254 nm UV in UV81KO cells was the same as in normal cells. Such clinical, cellular and molecular characteristics and comparison to those in the other photodermatoses (xeroderma pigmentosum, Cockayne's syndrome, the 11961 disorder, Bloom's syndrome) can make a clear distinction of UV81KO from the others.

  14. Synergistic photocatalysis of Cr(VI) reduction and 4-Chlorophenol degradation over hydroxylated α-Fe{sub 2}O{sub 3} under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ji-Chao; Ren, Juan [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China); Yao, Hong-Chang, E-mail: yaohongchang@zzu.edu.cn [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China); Zhang, Lin; Wang, Jian-She; Zang, Shuang-Quan [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China); Han, Li-Feng [Henan Provincial Key Laboratory of Surface & Interface Science, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Li, Zhong-Jun, E-mail: lizhongjun@zzu.edu.cn [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China)

    2016-07-05

    Highlights: • The surface hydroxyl of Fe{sub 2}O{sub 3} influences on the Cr(VI) reduction activity. • The synergistic photocatalysis enhances degradation activity of Cr(VI) and 4-CP. • The Fe{sub 2}O{sub 3} catalyst exhibits good stability and degradation activity after 9 runs. - Abstract: A series of Fe{sub 2}O{sub 3} materials with hydroxyl are synthesized in different monohydric alcohol (C{sub 2} – C{sub 5}) solvents by solvothermal method and characterized by XRD, BET, XPS, TG and EA. The amount of hydroxyl is demonstrated to be emerged on the surface of the as-synthesized Fe{sub 2}O{sub 3} particles and their contents are determined to be from 7.99 to 3.74 wt%. The Cr(VI) reduction experiments show that the hydroxyl content of Fe{sub 2}O{sub 3} samples exacts great influence on the photocatalytic activity under visible light irradiation (λ > 400 nm) and that the Fe{sub 2}O{sub 3} sample synthesized in n-butyl alcohol exhibits the optimal photocatalytic activity. The synergistic photocatalysis for 4-Chlorophenol (4-CP) degradation and Cr(VI) reduction over above Fe{sub 2}O{sub 3} sample is further investigated. The photocatalytic ratio of Cr(VI) reduction are enhanced from 24.8% to 70.2% while that of 4-CP oxidation are increased from 13.5% to 47.8% after 1 h visible light irradiation. The Fe{sub 2}O{sub 3} sample keeps good degradation rates of mixed pollutants after 9 runs. The active oxygen intermediates O{sub 2}{sup −}·, ·OH and H{sub 2}O{sub 2} formed in the photoreaction process are discovered by ESR measurement and UV–vis test. The photocatalytic degradation mechanism is proposed accordingly.

  15. Effect of some operational parameters on the hydrogen generation efficiency of Ni-ZnO/PANI composite under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nsib, Mohamed Faouzi, E-mail: Mohamed.faouzi.ncib@gmail.com [URCMEP (UR11ES85), Faculty of Sciences, University of Gabès, 6029 Gabès (Tunisia); National School of Engineers (ENIG), University of Gabès, 6029 Gabès (Tunisia); Naffati, Naima [URCMEP (UR11ES85), Faculty of Sciences, University of Gabès, 6029 Gabès (Tunisia); Rayes, Ali; Moussa, Noomen [URCMEP (UR11ES85), Faculty of Sciences, University of Gabès, 6029 Gabès (Tunisia); National School of Engineers (ENIG), University of Gabès, 6029 Gabès (Tunisia); Houas, Ammar [URCMEP (UR11ES85), Faculty of Sciences, University of Gabès, 6029 Gabès (Tunisia); Al Imam Mohammad Ibn Saud Islamic University (IMSIU), College of Sciences, Department of Chemistry, Riyadh 11623 (Saudi Arabia)

    2015-10-15

    Graphical abstract: UV–vis spectra of PANI, ZnO, Ni{sub 0.01}Zn{sub 0.99}O, Ni{sub 0.01}Zn{sub 0.99}O/PANI3 and Ni{sub 0.1}Zn{sub 0.9}O/PANI{sub 10} nanocomposites. - Highlights: • Ni{sub x}Zn{sub 1−x}O/PANI{sub y} photocatalysts are synthesized by the impregnation method. • Ni{sup 2+} amount control the morphology of ZnO and enhances its photoactivity. • Both Ni{sup 2+} and PANI extend the light absorption of ZnO toward the visible region. • Both Ni{sup 2+} and PANI enhance the electron–hole separation. - Abstract: Ni{sub x}Zn{sub 1−x}O/Polyaniline hybrid photocatalysts are synthesized and used for the experiments of hydrogen production from water-splitting under visible irradiation. XRD, UV–vis DRS and SEM are used to characterize the prepared materials. It is shown that the Ni{sup 2+} amount doped into ZnO controls its morphology and enhances its photoactivity for H{sub 2} generation. Polyaniline (PANI) is shown to sensitize ZnO and to extend its light absorption toward the visible region. The hybrid photocatalyst with 10 mol% Ni{sup 2+} and 10 wt.% PANI shows the maximum photocatalytic H{sub 2} production for one hour of visible irradiation: ∼558 μmol while only ∼178 μmol in the presence of pure ZnO. Additives like sacrificial electron donors and carbonate salts are found to play a key role in the improvement of H{sub 2} evolution. Thus, the hydrogen photoproduction efficiency increases in the order: thiosulfate > sulfide > propanol and HCO{sub 3}{sup −} > CO{sub 3}{sup 2−}.

  16. Effect of Different Activated Carbon as Carrier on the Photocatalytic Activity of Ag-N-ZnO Photocatalyst for Methyl Orange Degradation under Visible Light Irradiation.

    Science.gov (United States)

    Chen, Xiaoqing; Wu, Zhansheng; Gao, Zhenzhen; Ye, Bang-Ce

    2017-09-05

    In order to enhance the photodegradation of methyl orange (MO) by ZnO under visible light irradiation, ZnO nanoparticles co-doped with Ag and N and supported on activated carbon (AC) with different properties were synthesized through the sol-gel method. The prepared photocatalysts were characterized in terms of the structure and properties through X-ray diffraction, N₂ adsorption-desorption, ultraviolet-visible (UV-vis), diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, photoluminescence, and electron spin resonance. The photocatalytic activities of these photocatalysts followed the order: Ag-N-ZnO/ACs > Ag-N-ZnO > N, or Ag single-doped ZnO > commercial ZnO. This result was attributed to the small particle size, large surface area, narrow band gap, and high charge separation of Ag-N-ZnO/ACs. The Ag-N-ZnO/coconut husk activated carbon (Ag-N-ZnO/CHAC) exhibited the highest degradation efficiency of 98.82% for MO under visible light irradiation. This outcome was due to the abundant pore structure of Ag-N-ZnO/CHAC, resulting in stronger adsorption than that of other Ag-N-ZnO/ACs. Moreover, the degradation of MO on photocatalysis followed first order kinetics. The reactive species ·OH and ·O₂ - played more important roles in the photocatalytic degradation of MO over composite photocatalyst. Ag-N-ZnO/CHAC photocatalyst exhibited higher photocatalytic activity than unsupported Ag-N-ZnO after five recycling runs.

  17. Influence of light transmittance and background reflectance on the light curing of adhesives used to bond esthetic brackets.

    Science.gov (United States)

    Lim, Yong-Kyu; Lee, Yong-Keun

    2007-07-01

    The objectives of this study were to determine the correlation between diffuse light transmittance (DLT) of esthetic brackets and the degree of cure (DC) of light-cured adhesives after direct irradiation, and to evaluate the influence of background reflectance. The influences of curing unit and irradiation time were also determined. The DLT of 4 ceramic and 4 plastic brackets was measured. Two reference light-curing protocols (cured over a glass slab; mean reflectance, 14.7%) and 4 experimental protocols (cured over bovine tooth slab; mean reflectance, 66.5%) were followed with 3 curing units: halogen, plasma arc, and light-emitting diode. The DC of 2 adhesives was calculated based on Fourier transform infrared spectroscopy. Two-way analysis of variance for the DC was performed (P = .05). The Pearson correlation between the DC and the DLT was determined. Mean DLTs were 44.9% to 75.9%. DC varied by bracket and curing protocol (P bracket. The interaction of the DLT and the reflectance of the background tooth on the light curing of adhesives should be studied further.

  18. Halogen bonding origin properties and applications

    Science.gov (United States)

    Hobza, Pavel

    2015-12-01

    σ-hole bonding represents an unusual and novel type of noncovalent interactions in which atom with σ- hole interacts with Lewis base such as an electronegative atom (oxygen, nitrogen, …) or aromatic systems. This bonding is of electrostatic nature since the σ-hole bears a positive charge. Dispersion energy forms equally important energy term what is due to the fact that two heavy atoms (e.g. halogen and oxygen) having high polarizability lie close together (the respective distance is typically shorter than the sum of van der Waals radii). Among different types of σ-hole bondings the halogen bonding is by far the most known but chalcogen and pnictogen bondings are important as well.

  19. Halogen bonding origin properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Hobza, Pavel [Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague (Czech Republic); Regional Center of Advanced Technologies and Materials, Department of Physical Chemistry, Palacky University, 77146 Olomouc (Czech Republic)

    2015-12-31

    σ-hole bonding represents an unusual and novel type of noncovalent interactions in which atom with σ- hole interacts with Lewis base such as an electronegative atom (oxygen, nitrogen, …) or aromatic systems. This bonding is of electrostatic nature since the σ-hole bears a positive charge. Dispersion energy forms equally important energy term what is due to the fact that two heavy atoms (e.g. halogen and oxygen) having high polarizability lie close together (the respective distance is typically shorter than the sum of van der Waals radii). Among different types of σ-hole bondings the halogen bonding is by far the most known but chalcogen and pnictogen bondings are important as well.

  20. Preparation and characterization of WO3/Bi3O4Cl nanocomposite and its photocatalytic behavior under visible light irradiation

    CSIR Research Space (South Africa)

    Chakraborty, AK

    2012-01-01

    Full Text Available and Kebede MA2 1Department of Applied Chemistry and Chemical Technology, Islamic University, Kushtia 7003, Bangladesh 2CSIR. Materials Science and Manufacturing Email: akc_iu@yahoo.co.uk Abstract The highly efficient and visible light (? ? 420 nm...

  1. Degradation kinetics of aflatoxin B1 and B2 in filter paper and rough rice by using pulsed light irradiation

    Science.gov (United States)

    Rough rice is susceptible to contamination by aflatoxins, which are highly toxic, mutagenic and carcinogenic compounds. To develop aflatoxin degradation technology for rice with the use of pulsed light (PL) treatment, the objective of this study was to investigate the degradation characters of aflat...

  2. Preparation of novel Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts and their activities under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    He, Guo-Hua; Liang, Can-Jian; Ou, Yu-Da; Liu, Dan-Ni; Fang, Yue-Ping [Institute of Biomaterial, College of Science, South China Agricultural University, Guangzhou 510642 (China); Xu, Yue-Hua, E-mail: xuyuehua@scau.edu.cn [Institute of Biomaterial, College of Science, South China Agricultural University, Guangzhou 510642 (China)

    2013-06-01

    Highlights: ► Visible-light-driven Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts were synthesized. ► Results showed that RhB can be decomposed using a 4 W LED lamp as visible light. ► The coupling of Sb{sub 2}O{sub 3} and WO{sub 3} enhanced the photocatalytic activity of WO{sub 3}. - Abstract: Novel visible-light-driven Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts were prepared by a hydrothermal synthesis followed by heat treatment, and characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET surface area, Fourier transform infrared spectroscopy (FT-IR) and photoluminescence spectra (PL). The photocatalytic activities of Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts were evaluated by the rhodamine B degradation using a LED lamp as visible light irradiation. Compared with pure WO{sub 3} and Sb{sub 2}O{sub 3}, the significantly enhanced photocatalytic activities of the Sb{sub 2}O{sub 3}/WO{sub 3} composite particles are attributed to the decrease of the recombination rate of photoinduced electron–hole pairs due to the coupling of Sb{sub 2}O{sub 3} and WO{sub 3} within the composite nanoparticles. Studies of Sb{sub 2}O{sub 3}/WO{sub 3} composites indicate that one approach to design composite materials with enhanced photocatalytic performance is through coupling Sb{sub 2}O{sub 3} with WO{sub 3}, which the lowest energy states for electrons and holes are in different semiconductors.

  3. Fabrication of TiO{sub 2}/Ag{sub 2}O heterostructure with enhanced photocatalytic and antibacterial activities under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bingkun, E-mail: liubk2015@zzuli.edu.cn [School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Mu, Lilong; Han, Bing [School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Zhang, Jingtao [School of Food and Bioengineering, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Shi, Hengzhen, E-mail: shihz@zzuli.edu.cn [School of Material and Chemical Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002 (China)

    2017-02-28

    Highlights: • TiO{sub 2}/Ag{sub 2}O composite photocatalyst was synthesized successfully. • The composites show better photocatalytic activity for MB under visible light. • The composites also possess good antibacterial properties. • The mechanism of enhanced photocatalytic activities was investigated. - Abstract: TiO{sub 2}/Ag{sub 2}O heterostructure prepared by a facile in situ precipitation route was used as an effective visible light-driven photocatalyst for degradation of methylene blue (MB) and inactivation of E. coli. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed that Ag{sub 2}O nanoparticles were well distributed on the surface of TiO{sub 2} microspheres. The TiO{sub 2}/Ag{sub 2}O composite with optimal mass ratio of TiO{sub 2} and Ag{sub 2}O displayed extremely good photodegradation ability and antibacterial capability under visible light irradiation, which was mainly ascribed to the synergistic effect between Ag{sub 2}O and TiO{sub 2,} including highly dispersed smaller Ag{sub 2}O particles, increased visible light absorption and efficient separation of photo-induced charge carriers. Meanwhile, the roles of the radical species in the photocatalysis process were investigated. Our results showed that the TiO{sub 2}/Ag{sub 2}O could be used as a dual functional material in water treatment of removing the organic pollutant and killing the bacterium at the same time.

  4. A comparison study of rhodamine B photodegradation over nitrogen-doped lamellar niobic acid and titanic acid under visible-light irradiation.

    Science.gov (United States)

    Li, Xiukai; Kikugawa, Naoki; Ye, Jinhua

    2009-01-01

    A solid-state reaction method with urea as a nitrogen precursor was used to prepare nitrogen-doped lamellar niobic and titanic solid acids (i.e., HNb(3)O(8) and H(2)Ti(4)O(9)) with different acidities for visible-light photocatalysis. The photocatalytic activities of the nitrogen-doped solid acids were evaluated for rhodamine B (RhB) degradation and the results were compared with those obtained over the corresponding nitrogen-doped potassium salts. Techniques such as XRD, BET, SEM, X-ray photoelectron spectroscopy, and UV-visible diffuse reflectance spectroscopy were adopted to explore the nature of the materials as well as the characteristics of the doped nitrogen species. It was found that the intercalation of the urea precursor helped to stabilize the layered structures of both lamellar solid acids and enabled easier nitrogen doping. The effects of urea intercalation were more significant for the more acidic HNb(3)O(8) sample than for the less acidic H(2)Ti(4)O(9). Compared with the nitrogen-doped KNb(3)O(8) and K(2)Ti(4)O(9) samples, the nitrogen-doped HNb(3)O(8) and H(2)Ti(4)O(9) solid acids absorb more visible light and exhibit a superior activity for RhB photodegradation under visible-light irradiation. The nitrogen-doped HNb(3)O(8) sample performed the best among all the samples. The results of the current study suggest that the protonic acidity of the lamellar solid-acid sample is a key factor that influences nitrogen doping and the resultant visible-light photocatalysis.

  5. Melatonin and amfenac modulate calcium entry, apoptosis, and oxidative stress in ARPE-19 cell culture exposed to blue light irradiation (405 nm).

    Science.gov (United States)

    Argun, M; Tök, L; Uğuz, A C; Çelik, Ö; Tök, Ö Y; Naziroğlu, M

    2014-06-01

    Under conditions of oxidative stress, cell apoptosis is triggered through the mitochondrial intrinsic pathway. Increased levels of reactive oxygen species (ROS) are linked to excess cell loss and mediate the initiation of apoptosis in a diverse range of cell types. The aims of this study were to assess intracellular Ca(2+) release, ROS production, and caspase-3, and -9 activation in ARPE-19 cells during the blue light-mediated cell death, and to examine a potential protective effect of melatonin and amfenac, in the apoptotic cascade. ARPE-19 cells were cultured in their medium. First, MTT tests were performed to determine the protective effects of amfenac and melatonin. Cells were then exposed to blue light irradiation in an incubator. Intracellular Ca(2+) release experiments, mitochondrial membrane depolarization, apoptosis assay, glutathione (GSH), glutathione peroxidase (GSH-Px), and ROS experiments were done according to the method stated in the Materials and methods section. Cell death was clearly associated with increased levels of ROS production, as measured by 2',7'-dichlorofluorescein fluorescence, and associated increase in Ca(2+) levels, as measured by Fura-2-AM. Blue light-induced cell death was associated with an increased level of caspase-3 and 9, suggesting mediation via the apoptotic pathway. Cell death was also associated with mitochondrial depolarization. Melatonin was shown to delay these three steps. Melatonin, amfenac, and their combination protect ARPE-19 cells against blue light-triggered ROS accumulation and caspase-3 and -9 activation. The antiapoptotic effect of melatonin and amfenac at doses inhibiting caspase synthesis modified Ca(2+) release and prevented excessive ROS production, suggesting a new therapeutic approach to age-related macular degeneration.

  6. Effect of emitted wavelength and light guide type on irradiance discrepancies in hand-held dental curing radiometers.

    Science.gov (United States)

    Kameyama, Atsushi; Haruyama, Akiko; Asami, Masako; Takahashi, Toshiyuki

    2013-01-01

    The purpose of this study was to determine any discrepancies in the outputs of five commercial dental radiometers and also to evaluate the accuracy of these devices using a laboratory-grade spectroradiometer. The power densities of 12 different curing light sources were repeatedly measured for a total of five times using each radiometer in a random order. The emission spectra of all of the curing light sources were also measured using the spectroradiometer, and the integral value of each spectrum was calculated to determine the genuine power densities, which were then compared to the displayed power densities measured by the dental radiometers. The displayed values of power density were various and were dependent on the brand of radiometer, and this may be because each radiometer has a different wavelength sensitivity. These results cast doubt upon the accuracy of commercially available dental radiometers.

  7. Enzymatic halogenation and dehalogenation reactions: pervasive and mechanistically diverse

    OpenAIRE

    Agarwal, Vinayak; Miles, Zachary D.; Winter, Jaclyn M.; Eustáquio, Alessandra S; El Gamal, Abrahim A.; Moore, Bradley S

    2017-01-01

    Naturally produced halogenated compounds are ubiquitous across all domains of life where they perform a multitude of biological functions and adopt a diversity of chemical structures. Accordingly, a diverse collection of enzyme catalysts to install and remove halogens from organic scaffolds has evolved in nature. Accounting for the different chemical properties of the four halogen atoms (fluorine, chlorine, bromine, and iodine) and the diversity and chemical reactivity of their organic substr...

  8. A computational model for heterogeneous heating during pulsed laser irradiation of polymers doped with light-absorbing microparticles

    DEFF Research Database (Denmark)

    Marla, Deepak; Zhang, Yang; Jabbaribehnam, Mirmasoud

    2016-01-01

    Doping of polymers with light-absorbing microparticles to increase their optical properties is a commonly used pre-treatment technique in laser processing of polymers. The presence of these particles plays an important role during laser heating of the polymer that influences its surface character......Doping of polymers with light-absorbing microparticles to increase their optical properties is a commonly used pre-treatment technique in laser processing of polymers. The presence of these particles plays an important role during laser heating of the polymer that influences its surface...... characteristics. This work presents a study based on a computational model of laser heating of polymer doped with light-absorbing microparticles accounting for the heterogeneous nature of heating. The work aims at gaining a fundamental insight into the nature of the heating process and to understand the role...... of microparticles. The results suggest that apart from the laser intensity and pulse duration, the properties of the microparticles including their size and distribution also play an important role during the laser heating of polymers....

  9. Light

    CERN Document Server

    Ditchburn, R W

    1963-01-01

    This classic study, available for the first time in paperback, clearly demonstrates how quantum theory is a natural development of wave theory, and how these two theories, once thought to be irreconcilable, together comprise a single valid theory of light. Aimed at students with an intermediate-level knowledge of physics, the book first offers a historical introduction to the subject, then covers topics such as wave theory, interference, diffraction, Huygens' Principle, Fermat's Principle, and the accuracy of optical measurements. Additional topics include the velocity of light, relativistic o

  10. Synthesis of Nitrogen-Doped ZnS with Camellia Brushfield Yellow Nanostructures for Enhanced Photocatalytic Activity under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Gang-Juan Lee

    2013-01-01

    Full Text Available Nitrogen modified zinc sulfide photocatalysts were successfully prepared and characterized by X-ray diffraction (XRD, field emission scanning electron microscopy (FE-SEM, high-resolution transmission electron microscopy (HR-TEM, X-ray photoelectron spectroscopy (XPS, and surface area analysis. Thermal decomposition of the semisolid was carried out under nitrogen conditions at 500°C for 2 hours, and a series of nitrogen-doped ZnS photocatalysts were produced by controlling inflow flow rate of nitrogen at 15–140 mL/min. Optical characterizations of the synthesized N-doping ZnS substantially show the shifted photoabsorption properties from ultraviolet (UV region to visible light. The band gaps of nitrogen-doped ZnS composite catalysts were calculated to be in the range of 2.58~2.74 eV from the absorptions edge position. The 15N/ZnS catalyst shows the highest photocatalytic activity, which results in 75.7% degradation of Orange II dye in 5 hrs by visible light irradiation, compared with pristine ZnS and higher percentage N-doping ZnS photocatalysts.

  11. Ni(dmgH2 complex coupled with metal-organic frameworks MIL-101(Cr for photocatalytic H2 evolution under visible light irradiation

    Directory of Open Access Journals (Sweden)

    Rong Wang

    2017-03-01

    Full Text Available Metal-organic frameworks (MOFs have been tremendously used as photocatalysts for H2 generation in recent years. Lacking native active sites (so-called co-catalyst for H2 generation motivates the incorporation of noble metals and their molecular complexes, hydrogenase active site mimics into MOFs to promote H2 generation. We herein report an noble-metal-free photocatalytic H2 generation system consisting of Erythrosin B dye-sensitized MIL-101(Cr as a light absorber and Ni(dmgH2 as a co-catalyst. It is found that Ni(dmgH2 can serve as an efficient co-catalyst to boost H2 generation in the presence of triethanolamine (TEOA as an electron donor under visible light irradiation. The optimal MIL-101(Cr/Ni(dmgH2 hybrid (5 wt% Ni(dmgH2 displays a hydrogen H2 rate of 45.5 μmol h−1, which is 10 times greater than the control sample without Ni(dmgH2 loading. This paper provides a novel design route for active H2 generation systems by combining molecular complexes of earth-abundant metal and MOFs photocatalysts.

  12. The effects of hydrothermal temperature on the photocatalytic performance of ZnIn{sub 2}S{sub 4} for hydrogen generation under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Fei [Harbin Institute of Technology Shenzhen Graduate School, Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055 (China); Zhu, Rongshu, E-mail: rszhu@hitsz.edu.cn [Harbin Institute of Technology Shenzhen Graduate School, Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055 (China); Public Platform for Technological Service in Urban Waste Reuse and Energy Regeneration, Shenzhen 518055 (China); Song, Kelin; Niu, Minli [Harbin Institute of Technology Shenzhen Graduate School, Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055 (China); Ouyang, Feng, E-mail: Ouyangfh@hit.edu.cn [Harbin Institute of Technology Shenzhen Graduate School, Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055 (China); Public Platform for Technological Service in Urban Waste Reuse and Energy Regeneration, Shenzhen 518055 (China); Cao, Gang, E-mail: caog@hotmail.com [Harbin Institute of Technology Shenzhen Graduate School, Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055 (China); Public Platform for Technological Service in Urban Waste Reuse and Energy Regeneration, Shenzhen 518055 (China)

    2015-10-15

    Highlights: • The ZnIn{sub 2}S{sub 4} (120, 140, 160, 180, and 200 °C) was prepared. • The activities splitting water to hydrogen under visible light were evaluated. • The activity achieved the best when hydrothermal temperature was 160 °C. • The activity order is related to the surface morphology and surface defects. - Abstract: A series of ZnIn{sub 2}S{sub 4} photocatalysts were successfully synthesized using the hydrothermal method with different hydrothermal temperatures (120, 140, 160, 180, and 200 °C) and characterized by various analysis techniques, such as UV–vis, XRD, SEM, BET and PL. The results indicated that these photocatalysts had a similar band gap. The hydrothermal temperature had a huge influence on the properties of the photocatalysts such as the BET surface area, the total pore volume, the average pore diameter, the defects and the morphology. The photocatalytic activities of ZnIn{sub 2}S{sub 4} were evaluated based on photocatalytic hydrogen production from water under visible-light irradiation. The activity order is attributed to the coefficient of the surface morphology and the surface defects. The hydrogen production efficiency achieved the best when the hydrothermal temperature was 160 °C. On the basis of the characterization of the catalysts, the effects of the hydrothermal temperature on the photocatalytic activity of ZnIn{sub 2}S{sub 4} were discussed.

  13. Novel Au/CaIn{sub 2}S{sub 4} nanocomposites with plasmon-enhanced photocatalytic performance under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jie; Meng, Suci, E-mail: mengsc@ujs.edu.cn; Wang, Tianyong; Xu, Qing; Shao, Leqiang; Jiang, Deli, E-mail: dlj@ujs.edu.cn; Chen, Min

    2017-02-28

    Highlights: • Au/CaIn{sub 2}S{sub 4} nanocomposites were fabricated by a simple photoreduction process. • The nanocomposites shown plasmon-enhanced visible light photocatalytic activity. • The enhanced activity was mainly due to improved separation of charge carriers. • The superoxide radicals and holes are the two main photoactive species. - Abstract: A series of Au/CaIn{sub 2}S{sub 4} nanocomposites with different Au contents were prepared by a simple photoreduction process. Under visible light irradiation, the as-prepared Au/CaIn{sub 2}S{sub 4} nanocomposites exhibited plasmon-enhanced photocatalytic activity for the degradation of methylene blue (MB) compared to that of bare CaIn{sub 2}S{sub 4}. The sample with 4 wt% Au hybridized CaIn{sub 2}S{sub 4} exhibited the highest photocatalytic efficiency for MB degradation compared with those of the other nanocomposites. The mechanism for improving the photocatalytic performance of the Au/CaIn{sub 2}S{sub 4} nanocomposites was proposed by using the photoluminescence measurement and electrochemical analyses. The enhanced photocatalytic performance could be attributed to the high separation efficiency of the photogenerated electron-hole pairs. This work could provide a new insight into the fabrication of CaIn{sub 2}S{sub 4}-based plasmonic photocatalysts with enhanced performance.

  14. Photocatalytic degradation of gaseous toluene on Fe-TiO{sub 2} under visible light irradiation: A study on the structure, activity and deactivation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Sun Song; Ding Jianjun [National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230029 (China); Bao Jun, E-mail: baoj@ustc.edu.cn [National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230029 (China); Gao Chen [National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230029 (China); Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Qi Zeming; Yang Xiaoyan; He Bo; Li Chengxiang [National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230029 (China)

    2012-04-01

    The Fe-TiO{sub 2} photocatalysts synthesized by a sol-gel method have the mesoporous structure with a narrow pore size distribution, large pore volume and high surface area. The incorporated Fe{sup 3+} substitutes the octahedrally coordinated Ti{sup 4+} in the TiO{sub 2} lattice to extend the absorption of TiO{sub 2} to visible light region and promote the formation of electron-hole pair. Additionally, the separation and transportation efficiency increase with the doping of Fe{sup 3+} increasing from 0.1% to 0.7%, while decreases remarkably with the doping concentration increasing from 0.7% to 1.5%. The Fe-TiO{sub 2} shows excellent photocatalytic performance for toluene degradation under visible light irradiation. The optimal Fe/Ti ratio is 0.7%. Partial deactivation of the photocatalytic activity was observed after 20 consecutive reaction runs. From the in situ DRIFTS experiment, the deactivation reason can be attributed to the formation of stable intermediates, such as benzaldehyde and benzoic acid, which occupied the active sites on the surface of the photocatalyst. The adsorbed benzaldehyde and benzoic acid can be removed with heat treatment at 653 K for 3 h and the deactivated photocatalyst can be regenerated completely.

  15. Highly antibacterial activity of N-doped TiO{sub 2} thin films coated on stainless steel brackets under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shuai; Liu, Bo; Fan, Lingying; Yue, Ziqi [Department of Orthodontics, School of Stomatology, Lanzhou University, Lanzhou 730000 (China); Liu, Bin [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Cao, Baocheng, E-mail: caobch@lzu.edu.cn [Department of Orthodontics, School of Stomatology, Lanzhou University, Lanzhou 730000 (China)

    2014-08-01

    In this study, the radio frequency (RF) magnetron sputtering method was used to prepare a TiO{sub 2} thin film on the surface of stainless steel brackets. Eighteen groups of samples were made according to the experimental parameters. The crystal structure and surface morphology were characterized by X-ray diffraction, and scanning electron microscopy, respectively. The photocatalytic properties under visible light irradiation were evaluated by measuring the degradation ratio of methylene blue. The sputtering temperature was set at 300 °C, and the time was set as 180 min, the ratio of Ar to N was 30:1, and annealing temperature was set at 450 °C. The thin films made under these parameters had the highest visible light photocatalytic activity of all the combinations of parameters tested. Antibacterial activities of the selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. The results demonstrated the thin film prepared under the parameters above showed the highest antibacterial activity.

  16. Design of Composite Photocatalyst of TiO2 and Y-Zeolite for Degradation of 2-Propanol in the Gas Phase under UV and Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Takashi Kamegawa

    2014-10-01

    Full Text Available Hydrophobic Y-zeolite (SiO2/Al2O3 = 810 and TiO2 composite photocatalysts were designed by using two different types of TiO2 precursors, i.e., titanium ammonium oxalate and ammonium hexafluorotitanate. The porous structure, surface property and state of TiO2 were investigated by various characterization techniques. By using an ammonium hexafluorotitanate as a precursor, hydrophobic modification of the Y-zeolite surface and realizing visible light sensitivity was successfully achieved at the same time after calcination at 773 K in the air. The prepared sample still maintained the porous structure of Y-zeolite and a large surface area. Highly crystalline anatase TiO2 was also formed on the Y-zeolite surface by the role of fluorine in the precursor. The usages of ammonium hexafluorotitanate were effective for the improvement of the photocatalytic performance of the composite in the degradation of 2-propanol in the gas phase under UV and visible light (λ > 420 nm irradiation.

  17. Design of composite photocatalyst of TiO2 and Y-zeolite for degradation of 2-propanol in the gas phase under UV and visible light irradiation.

    Science.gov (United States)

    Kamegawa, Takashi; Ishiguro, Yasushi; Kido, Ryota; Yamashita, Hiromi

    2014-10-13

    Hydrophobic Y-zeolite (SiO2/Al2O3 = 810) and TiO2 composite photocatalysts were designed by using two different types of TiO2 precursors, i.e., titanium ammonium oxalate and ammonium hexafluorotitanate. The porous structure, surface property and state of TiO2 were investigated by various characterization techniques. By using an ammonium hexafluorotitanate as a precursor, hydrophobic modification of the Y-zeolite surface and realizing visible light sensitivity was successfully achieved at the same time after calcination at 773 K in the air. The prepared sample still maintained the porous structure of Y-zeolite and a large surface area. Highly crystalline anatase TiO2 was also formed on the Y-zeolite surface by the role of fluorine in the precursor. The usages of ammonium hexafluorotitanate were effective for the improvement of the photocatalytic performance of the composite in the degradation of 2-propanol in the gas phase under UV and visible light (λ > 420 nm) irradiation.

  18. Preparation and characterization of p–n heterojunction CuBi2O4/CeO2 and its photocatalytic activities under UVA light irradiation

    Directory of Open Access Journals (Sweden)

    Abdelkader Elaziouti

    2015-04-01

    Full Text Available CuBi2O4/CeO2 nanocomposites were synthesized by the solid state method and were characterized by a number of techniques such as X-ray diffraction, scanning electron microscopy and UV–Vis diffuse reflectance spectroscopy. The photocatalytic activity of the samples was investigated under UVA light and assessed using Congo red (CR dye as probe reaction. The efficiency of the coupled CuBi2O4/CeO2 photocatalyst was found to be related to the amount of added CuBi2O4 and to the pH medium. The CuBi2O4/CeO2 photocatalyst exhibited the high efficiency as a result of 83.05% of degradation of CR under UVA light for 100 min of irradiation time with 30 wt% of CuBi2O4 at 25 °C and pH 7, which is about 6 times higher than that of CeO2. The photodegradation reactions satisfactorily correlated with the pseudo-first-order kinetic model. The mechanism of the enhanced photocatalytic efficiency was explained by the heterojunction model.

  19. Highly antibacterial activity of N-doped TiO2 thin films coated on stainless steel brackets under visible light irradiation

    Science.gov (United States)

    Cao, Shuai; Liu, Bo; Fan, Lingying; Yue, Ziqi; Liu, Bin; Cao, Baocheng

    2014-08-01

    In this study, the radio frequency (RF) magnetron sputtering method was used to prepare a TiO2 thin film on the surface of stainless steel brackets. Eighteen groups of samples were made according to the experimental parameters. The crystal structure and surface morphology were characterized by X-ray diffraction, and scanning electron microscopy, respectively. The photocatalytic properties under visible light irradiation were evaluated by measuring the degradation ratio of methylene blue. The sputtering temperature was set at 300 °C, and the time was set as 180 min, the ratio of Ar to N was 30:1, and annealing temperature was set at 450 °C. The thin films made under these parameters had the highest visible light photocatalytic activity of all the combinations of parameters tested. Antibacterial activities of the selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. The results demonstrated the thin film prepared under the parameters above showed the highest antibacterial activity.

  20. Functionalization of a plasmonic Au/TiO2 photocatalyst with an Ag co-catalyst for quantitative reduction of nitrobenzene to aniline in 2-propanol suspensions under irradiation of visible light.

    Science.gov (United States)

    Tanaka, Atsuhiro; Nishino, Yuri; Sakaguchi, Satoshi; Yoshikawa, Takayuki; Imamura, Kazuya; Hashimoto, Keiji; Kominami, Hiroshi

    2013-03-28

    A functionalized plasmonic Au/TiO2 photocatalyst with an Ag co-catalyst was successfully prepared by the combination of two types of photodeposition methods, and it quantitatively converted nitrobenzene and 2-propanol to aniline and acetone under irradiation of visible light.