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Halogen Lamp (halogen + lamp)
Selected AbstractsPhotoelectrocatalytic Oxidation of NADH with Electropolymerized Toluidine Blue OELECTROANALYSIS, Issue 2-3 2007Yusuf Dilgin Abstract A poly(Toluidine Blue O) (poly-TBO) modified electrode was successfully prepared by repeated sweeping the applied potential from ,0.6 to +0.8,V (vs. SCE) on a glassy carbon electrode (GCE) in borate buffer solution at pH,9.1,containing 0.1,M NaNO3 and 0.4,mM Toluidine Blue O (TBO). The poly-TBO modified GCE shows electrocatalytic activity toward NADH oxidation in phosphate buffer solution at pH,7.0, with an overpotential of ca. 350,mV lower than that at the bare electrode. The photoelectrocatalytic oxidation of NADH at this electrode was also successfully investigated by using cyclic voltammetry and amperometry at constant potential. When the modified electrode surface was irradiated with a 250,W halogen lamp, a photoelectrocatalytic effect was observed for NADH oxidation and the current was increased about 2.2 times. The applied potential was selected at +100,mV for amperometric and photoamperometric detection of NADH. A linear calibration graph for NADH was obtained in the range between 1.0×10,5 and 1.0×10,3 M and between 5.0×10,6 and 1.0×10,3 M for amperometric and photoamperometric studies, respectively. The effect of some interfering compounds, such as ascorbic acid and dopamine on the electrocatalytic and photoelectrocatalytic oxidation of NADH was tested. [source] Clinical grading of oral mucosa by curve-fitting of corrected autofluorescence using diffuse reflectance spectraHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 6 2010Rupananda Jayachandra Mallia PhD Abstract Background Laser-induced autofluorescence (LIAF) and diffuse reflectance (DR) were collectively used in this clinical study to improve early oral cancer diagnosis and tissue grading. Methods LIAF and DR emission from oral mucosa were recorded on a fiber-optic spectrometer by illumination with a 404-nm diode laser and tungsten halogen lamp in 36 healthy volunteers and 40 lesions of 20 patients. Results Absorption dips in LIAF spectra at 545 and 575 nm resulting from changes in oxygenated hemoglobin were corrected using DR spectra of the same site. These corrected spectra were curve-fitted using Gaussian spectral functions to determine constituent emission peaks and their relative contribution. The Gaussian peak intensity and area ratios F500/F635 and F500/F685 were found to be useful indicators of tissue transformation. The diagnostic capability of various ratios in differentiating healthy, hyperplastic, dysplastic, and squamous cell carcinomas (SCCs) were examined using discrimination scatterplots. Conclusions The LIAF/DR technique, in conjunction with curve-fitting, differentiates different grades of dysplasia and SCC in this clinical trial and proves its potential for early detection of oral cavity cancer and tissue grading. © 2009 Wiley Periodicals, Inc. Head Neck, 2010 [source] Fullerene-Promoted Singlet-Oxygen Photochemical Oxygenations in Glass-Polymer Microstructured ReactorsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2008Tommaso Carofiglio Abstract In this paper we report the fabrication of thiolene-based microstructured reactors (MRs) that have been specifically designed to include solid-supported reagents within the microchannels network. We propose a convenient solution to realize reversible press-fit, leak-proof interconnects that greatly simplify the MR coupling to the external environment such as capillary tubing, sample reservoirs and pumps. The MRs have been used to carry out the oxidation of ,-terpinene and methionine using [60]fullerene, covalently linked to Tentagel® and silica gel matrices, as a singlet oxygen sensitizer. High conversions have been observed for both substrates although, in the case of ,-terpinene, a partial photodegradation of the endo -peroxide product was detected. Interestingly, in the case of methionine, a quantitative conversion to the corresponding sulfoxides was achieved in about 40 seconds, using low-power, white LED illumination. The reaction time is considerably shorter when compared to the batch procedure that requires, for the same process, about one hour illumination and the use of a 300-W tungsten halogen lamp. [source] Orthodontic brackets removal under shear and tensile bond strength resistance tests , a comparative test between light sourcesLASER PHYSICS LETTERS, Issue 3 2008P.C.G. Silva Abstract We have investigated if a new LEDs system has enough efficient energy to promote efficient shear and tensile bonding strength resistance under standardized tests. LEDs 470 ± 10 nm can be used to photocure composite during bracket fixation. Advantages considering resistance to tensile and shear bonding strength when these systems were used are necessary to justify their clinical use. Forty eight human extracted premolars teeth and two light sources were selected, one halogen lamp and a LEDs system. Brackets for premolar were bonded through composite resin. Samples were submitted to standardized tests. A comparison between used sources under shear bonding strength test, obtained similar results; however, tensile bonding test showed distinct results: a statistical difference at a level of 1% between exposure times (40 and 60 seconds) and even to an interaction between light source and exposure time. The best result was obtained with halogen lamp use by 60 seconds, even during re-bonding; however LEDs system can be used for bonding and re-bonding brackets if power density could be increased. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Plasma lysozyme levels in sheatfish Silurus glanis (L.) subjected to stress and experimental infection with Edwardsiella tardaAQUACULTURE RESEARCH, Issue 12 2002D Caruso Abstract Two experiments were conducted to assess plasma lysozyme levels, leucocrit and haematocrit in juvenile sheatfish (90,140 g) under experimentally induced stress and infection. Stress was provoked by random modification of environmental light for 15 min, 16 times a day with a halogen lamp (500 W) and by holding fish in a net for 3 min twice a day. In the first trial, repeated measuring of marked sheatfish showed a progressive significant decrease in plasma lysozyme level, a significant increase in leucocrit and a significant decrease in haematocrit. After a rest period of 1 week, only the leucocrit value was back to the prestress value. In the second trial, light-induced stress did not lead to any variation in lysozyme, leucocrit or haematocrit values. However, after intraperitoneal injection of Edwardsiella tarda (7 × 108 cfu), a strong increase in plasmatic lysozyme in both stressed and unstressed groups of sheatfish was observed. The increase was significant vs. prechallenge levels 3 and 6 days after contamination, but no significant difference was detected between stressed and unstressed fish, despite the strongest stress (light+handling stress) applied to the fish at the beginning of contamination. Decreases in haematocrit values were observed in both groups of fish. A clear increase in leucocrit appeared in unstressed fish, whereas stressed fish showed a significant decrease in leucocrit values. Condition factor was significantly decreased by all kinds of stress. There were no difference in mortality between stressed and unstressed groups. [source] In vitro and in vivo comparison of two different light sources for topical photodynamic therapyBRITISH JOURNAL OF DERMATOLOGY, Issue 4 2006P. Babilas Summary Background, Photodynamic therapy (PDT) with 5-aminolaevulinic acid (ALA) is an effective and safe treatment option for the treatment of actinic keratosis (AK). Incoherent lamps are often used, matching the absorption maxima of ALA. Objectives, A comparative trial was performed to evaluate the efficacy of recently developed light-emitting diodes (LEDs). Methods, Human epidermal keratinocytes were incubated for 24 h with ALA (100, 200, 300, 400 or 500 ,mol L,1) and irradiated consecutively using either an incoherent halogen lamp (,em = 580,750 nm; 24 J cm,2; 40 mW cm,2) or an LED system (,em = 633 ± 3 nm; 3, 6, 12 or 24 J cm,2; 40 mW cm,2). Topical ALA-PDT was performed on 40 patients with AK (n = 584) in a symmetrical distribution suitable for two-sided comparison. After incubation with ALA (20% in cream base) irradiation was performed with the incoherent lamp (100 J cm,2; 160 mW cm,2) on one side and the LED system (40 J cm,2; 80 mW cm,2) on the opposite side followed by re-evaluation up to 6 months. Results, No significant differences between the LED system (3, 6, 12 or 24 J cm,2) and the incoherent light source (24 J cm,2) regarding cytotoxicity was found in vitro. The complete remission rate yielded in the in vivo investigation was also not significantly different at 6 weeks (P = 0·95), 3 months (P = 0·75) and 6 months (P = 0·61) following therapy. Six weeks following therapy complete remission rates of 84·3% (LED system) and 82·8% (incoherent lamp) were achieved. There was also no significant difference between both light sources regarding pain during light treatment (P = 0·67), patient satisfaction (P = 1·0) or cosmesis (P = 1·0) following therapy. Conclusions, These results show the efficacy of an LED system for ALA-PDT both in vitro and in vivo. ALA-PDT with the LED system showed a noninferiority regarding the clinical outcome in the treatment of AK compared with the incoherent lamp. [source] | |||||||||||||