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Results 451 - 500 of 828
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Langhals Heinz - - 2006
The synthesis of methoxyperylene bisimides and perylene lactame imides with aliphatic N-substituents is described. Both classes of dyes exhibit fluorescence in the bathochromic region of visible light so that red light is obtained. The lightfastness of the dyes is very high, thus, there is special interest for diverse applications.
Chiodo N - - 2006
We report a direct observation of Bloch-like dynamics of light in curved waveguide arrays manufactured in Er:Yb-doped phosphate glass by femtosecond laser writing. The green upconversion fluorescence emitted by excited erbium ions is exploited to image the flow of the guided pump light at approximately 980 nm along the array. ...
Cosgrove Jeffrey - - 2006
The use of microalgae suspensions in PAM-fluorometers such as the Water-PAM (Walz GmbH, Germany) presents the problem of maintaining a homogeneous sample. The Water-PAM is marketed with an optional accessory for stirring the sample within the cuvette while in the emitter-detector (ED) unit. This stirring device can help to prevent ...
Zhang M - - 2006
Through fluorescence-spectrum measurements, we investigated the effects of light-assisted oxidation with H2O2 (LAOx) on single-wall carbon nanotubes (SWNTs) that were individually dispersed in an aqueous solution of surfactant. The intensities of the fluorescence spectra were decreased remarkably by the LAOx when the light's wavelength was 400-500 nm and a little ...
Schansker Gert - - 2006
The dark recovery kinetics of the Chl a fluorescence transient (OJIP) after 15 min light adaptation were studied and interpreted with the help of simultaneously measured 820 nm transmission. The kinetics of the changes in the shape of the OJIP transient were related to the kinetics of the qE and ...
de Jong Ebbing P - - 2006
Fluorescence detectors are ever more frequently being used with light-emitting diodes (LEDs) as the light source. Technological advances in the solid-state lighting industry have produced LEDs which are also suitable tools in analytical measurements. LEDs are now available which deliver 700 mW of radiometric power. While this greater light power ...
Lincoln C A - - 2006
One of the primary aims of forensic examination in sexual offences is to detect and recover biological material that will link the offender with the complainant. One potentially valuable method by which trace biological evidence may be identified in other forensic settings is via the use of an Alternate Light ...
Zhao Shulin - - 2006
A highly sensitive optical fiber light-emitting diode (LED)-induced fluorescence detector for CE has been constructed and evaluated. In this detector, a violet or blue LED was used as the excitation source and an optical fiber with 40 microm OD was used to transmit the excitation light. The upper end of ...
Merkle Scott A - - 2006
Embryogenic cultures of loblolly pine (Pinus taeda L.), slash pine (Pinus elliottii Engelm.), longleaf pine (Pinus palustris Mill.) and slash pine x longleaf pine hybrids were initiated from immature seeds on an initiation medium containing 13.57 microM 2,4-dichlorophenoxyacetic acid and 2.22 microM benzylaminopurine. Embryogenic cultures proliferated and somatic embryos developed, ...
Weyermann Céline - - 2006
The determination of the age of an ink entry from a questioned document is often a major problem and a controversial issue in forensic sciences. Therefore, it is important to understand the aging process of the different components found in ink. The aim of this work is to characterize the ...
Himel Herman D HD - - 2006
Transmembrane voltage-sensitive fluorescent dyes are used to study electrical activity in hearts. Green and red fluorescence emissions from di-4-ANEPPS excited with 488 nm light indicate both transmembrane voltage changes and heart movement. We have previously shown that the ratio, green fluorescence divided by red fluorescence, indicates the transmembrane voltage without ...
Braga-Vilela Antonella Sachsida - - 2006
Pericardial connective tissue has been used to construct bioprostheses to repair various types of injuries, including aortic wall repairs. The arrangement and the distribution of elastic and collagen staple fibers are related directly to the biomechanical properties of the tissue and thus determine the choice tissue for the construction of ...
Pretty I A IA Dental Health Unit, 3A Skeleton House, Manchester Science Park, The University of Manchester, UK. - - 2006
When using quantitative light-induced fluorescence a number of factors can influence illumination level. The purpose of this study was to investigate, using a high-resolution camera and fibre-optic light source, the impact of illumination level and focal distance on common quantitative light-induced fluorescence outcomes. Twenty-four extracted teeth were examined using 6 ...
Star Willem M - - 2006
Photodynamic therapy (PDT) of superficial basal cell carcinoma using topical 5-aminolaevulinic acid (ALA) and 75-100 J/cm2 light dose yields unsatisfactory long-term results. In several animal models, illumination with two light fractions approximately 2 h apart was considerably more effective than single illumination, suggesting the need for a pilot clinical study. ...
Guo Honglian - - 2006
The breakage of fluorescence-labeled microtubules under irradiation of excitation light is found in our experiments. Its mechanism is studied. The results indicate that free radicals are the main reason for the photosensitive breakage. Furthermore, the mechanical properties of the microtubules are probed with a dual-optical tweezers system. It is found ...
Andersen Charlotte M - - 2005
Light-induced oxidation of semihard cheese has been evaluated by fluorescence spectroscopy. The cheese was packaged in two packaging materials and exposed to different storage conditions, which included light/dark storage, oxygen availability, and storage time (0, 4, 7, 14, 21, 42, 70, or 84 days). Fluorescence excitation-emission matrices (EEM) were analyzed ...
Bulina Maria E - - 2006
Photosensitizers are chromophores that generate reactive oxygen species (ROS) upon light irradiation. They are used for inactivation of specific proteins by chromophore-assisted light inactivation (CALI) and for light-induced cell killing in photodynamic therapy. Here we report a genetically encoded photosensitizer, which we call KillerRed, developed from the hydrozoan chromoprotein anm2CP, ...
Dragnea Vladimira V Department of Biology, Indiana University, Bloomington, Indiana 47405, USA. - - 2005
AppA is a blue-light and redox-responding regulator of photosynthesis gene expression in Rhodobacter sphaeroides. Detailed time-resolved fluorescence spectroscopy and subpicosecond transient absorption spectroscopy study of the BLUF domain is presented for wild-type AppA (AppAwt) and a photoinactive Y21F mutant of AppA. The main findings discussed here are that (1) time-resolved ...
Vukusic Pete - - 2005
Recently developed, high-efficiency, light-emitting diodes use two-dimensional photonic crystals to enhance the extraction of otherwise internally trapped light and multilayer reflectors to control the direction of light emission. This work describes the characterization of a naturally evolved light-extraction system on the wing scales of a small group of Papilio butterflies. ...
Davitt Kristina - - 2005
We demonstrate a compact system, incorporating a 32-element linear array of ultraviolet (290 nm and 340 nm) light-emitting diodes (LEDs) and a multi-anode photomultiplier tube, to the in-flight fluorescence detection of aerosolized particles, here containing the biological molecules tryptophan and NADH. This system illustrates substantial advances in the growth and ...
Kanakubo Akira - - 2005
2,3,5,6-Tetrabromohydroquinone was isolated as a luminous substance from Ptychodera flava. This compound emitted light after addition of hydrogen peroxide under basic conditions. Since hydroquinone had no fluorescence, further investigation by spectral analysis revealed that riboflavin was the only possible light emitter having green fluorescence. In the presence of both tetrabromohydroquinone ...
Xu Quanyun A - - 2005
PURPOSE: The physical and chemical compatibility of palonosetron with cyclophosphamide and with ifosfamide during simulated Y-site administration was studied. METHODS: Test samples were prepared in triplicate by mixing 7.5 mL of palonosetron hydrochloride 50 microg (of palonosetron) per milliliter with 7.5 mL of cyclophosphamide 10 mg/mL and with ifosfamide 20 ...
Kawasaki Mitsuo - - 2005
A highly reflective thick Ag island film (TAIF) sputter-grown on mica, consisting of unique large pseudotabular nanoislands, 60-200 nm across and 30-60 nm thick, produced an unusually strong surface enhanced fluorescence (SEF) for rhodamine dyes situated very close to (only approximately 10 A away from) the metal surface. A significantly ...
Han Mina - - 2005
We describe here the highly fluorescent self-assembled spherical aggregates of an azobenzene molecule without a specific ionic component in organic solution under UV light illumination. The first stage of trans-to-cis photoisomerization by UV light at 365 nm was followed by a significant enhancement, up to about 1000 times, of the ...
Palero J - - 2005
We report on a novel and simple light source for short-wavelength two-photon excitation fluorescence microscopy based on the visible nonsolitonic radiation from a photonic crystal fiber. We demonstrate tunability of the light source by varying the wavelength and intensity of the Ti:Sapphire excitation light source. The visible nonsolitonic radiation is ...
Haddock Steven H D - - 2005
Bioluminescence (light production) and fluorescence (re-emission of absorbed radiation as light) are found in an unaccountably diverse array of marine organisms, where their functions are largely unknown. Here we report a deep-sea siphonophore that twitches glowing lures to attract fish. This is rare evidence of bioluminescence used for prey attraction ...
Golovkova Tatiana A - - 2005
[reaction: see text] Photochromic dithienylethene moieties were covalently attached to fluorescent 4,4-difluoro-8-(4'-iodophenyl)-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (iodo-BODIPY) via a phenylacetylene linker. UV light induced isomerization of the photochrome results in significant decrease in fluorescence intensity. This fluorescence can be recovered with visible light. Steady-state fluorescence measurements demonstrate that the emission of the dye can ...
Prieto Pedro M PM Laboratorio de Optica, Universidad de Murcia, Edificio C, Campus de Espinardo, E-30071 Murcia, Spain. - - 2005
Reflection densitometry has been widely used to measure the density difference of the bleachable cone photopigments in human eyes. Most such measurements make a series of assumptions concerning the amount of scattered light to derive an estimate of the true cone photopigment density from the density difference measurements. The current ...
Habuchi Satoshi - - 2005
Reversible photoswitching of individual molecules has been demonstrated for a number of mutants of the green fluorescent protein (GFP). To date, however, a limited number of switching events with slow response to light have been achieved at the single-molecule level. Here, we report reversible photoswitching characteristics observed in individual molecules ...
Schansker Gert - - 2005
An alternative approach to quantification of the contribution of non-QB-reducing centers to Chl a fluorescence induction curve is proposed. The experimental protocol consists of a far-red pre-illumination followed by a strong red pulse to determine the fluorescence rise kinetics. The far-red pre-illumination induces an increase in the initial fluorescence level ...
Wawryk Jacob - - 2005
The detection of body fluids in cases of sexual assault or abuse is important for purposes of evidence collection and DNA testing. In cases where semen is deposited on skin, a method for detection of semen may be a valuable aid to evidence collection [Gabby T, Winkleby M, Boyce T, ...
Masci Jarod - - 2005
We report on the first attempts, using both light and fluorescence microscopy, to visualize the developing embryo of the butterfly Bicyclus anynana. We developed a new protocol that enabled the clear visualization of the internal egg structures in early embryogenesis (1-24 h after egg laying). Dechorionation was followed by fixation ...
Mangolini L - - 2005
Light emission from silicon based on quantum confinement in nanoscale structures has sparked intense research into this field ever since its discovery about 15 years ago. A barrier to the widespread utilization of luminescent silicon nanocrystals in such diverse application areas as optoelectronics, solid-state lighting for general illumination, or fluorescent ...
Gao Xiaohu - - 2005
Quantum dots (QDs), tiny light-emitting particles on the nanometer scale, are emerging as a new class of fluorescent probe for in vivo biomolecular and cellular imaging. In comparison with organic dyes and fluorescent proteins, QDs have unique optical and electronic properties: size-tunable light emission, improved signal brightness, resistance against photobleaching, ...
Bolker Jessica A - - 2005
Flounders offer unique opportunities to study the cytological basis of vertebrate pigmentation. Individual skin pigment cells are clearly visible at hatching, and flounder ontogeny includes a dramatic shift in overall pigmentation (from symmetrical to asymmetrical) during metamorphosis. Moreover, several types of malpigmentation occur in hatchery populations; although much effort has ...
Loidl W - - 2005
OBJECTIVE: The aim of this study was the assessment of flexible cystoscopy assisted by hexaminolevulinate (HAL) fluorescence. METHODS: This study was a prospective controlled, within-patient comparison of flexible HAL cystoscopy with standard flexible cystoscopy, HAL rigid and standard white light rigid cystoscopy. Eligible patients received an intravesical instillation of 50 ...
Matsubara Shizue - - 2004
Photosystem (PS) II centers, which split water into oxygen, protons, and electrons during photosynthesis, require light but are paradoxically inactivated by it. Prolonged light exposure concomitantly decreased both the functional fraction of PSII reaction centers and the integral PSII chlorophyll (Chl) a fluorescence lifetime in leaf segments of Capsicum annuum ...
Buchalla Wolfgang - - 2004
In this study, the light-emission properties of carious and sound root surfaces were investigated under a wide range of excitation wavelengths. Human molar teeth with exposed root surfaces containing light- and dark-discolored root caries (n = 3 of each) were selected. Emission spectra were recorded from carious and corresponding sound ...
Fukaminato Tuyoshi - - 2004
Photochromic reactions of diarylethene derivatives were detected at a single-molecule level by using a fluorescence technique. Fluorescent photoswitching molecules in which photochromic diarylethene and fluorescent bis(phenylethynyl)anthracene units are linked through an adamantyl spacer were synthesized, and switching of fluorescence upon irradiation with UV and visible light was followed in solution ...
Török B - - 2004
The supernatants obtained from mammalian tissue homogenates, blood serum or other body fluids, and supplemented with organic hydroperoxide show a multiplicity of light-emitting reactions. The low-level chemiluminescence of biological samples denotes that after hydroperoxide-induction electronically excited species are produced. The light-emission measured by photomultipliers is related to (i) the geometrical ...
Beyenal Haluk - - 2004
We have developed an optical microsensor to quantify fluorescent light intensity distribution in biofilms. The optical system consisted of a beam splitter, light couplers, filters and a spectrophotometer able to accept the fiberoptic cable to measure fluorescent light intensity. The emitted light, fluorescence from the biofilm, was collected at the ...
Kawauchi Satoko - - 2004
We revealed that in ATX-S10.Na(II)(13,17-bis (1-carboxypropionyl) carbamoylethyl-8-etheny-2-hydroxy-3-hydroxyiminoethylidene-2,7,12,18-tetraethyl porphyrin sodium)-mediated photodynamic therapy using 667 nm nanosecond-pulsed light excitation at a peak intensity of 2.0 MW/cm(2), phototoxicity increased with decreasing pulse repetition rate in the range of 5-30 Hz for A549 cell cultures. To examine the relation between the reaction mechanism and ...
Moise Nicolae - - 2004
We report the first direct decomposition of the fluorescence lifetime heterogeneity during multiphasic fluorescence induction in dark-adapted leaves by multi-frequency phase and modulation fluorometry (PMF). A very fast component, assigned to photosystem I (PSI), was found to be constant in lifetime and yield, whereas the two slow components, which are ...
Moise Nicolae - - 2004
The relationship between the fluorescence lifetime (tau) and yield (Phi) obtained in phase and modulation fluorometry at 54 MHz during the chlorophyll fluorescence induction in dark-adapted leaves under low actinic light has been investigated. Three typical phases have been identified: (i) linear during the OI photochemical rise, (ii) convex curvature ...
Markovic Dejan - - 2004
Simultaneous measurements of fluorescence and thermal emission have been made by a combined fluorescence and photoacoustic techniques on isolated thylakoids pretreated by a prolonged illumination of saturating light. The traces of the signals are used to calculate four characteristic parameters, energy storage, half-saturation intensity, number of photons to close reaction ...
Ciesielski B - - 2004
Exposure of gamma-irradiated L-alanine samples to sunlight and to light from a regular, fluorescent lamp resulted in significant changes in their EPR resonance patterns, both to spectral shapes and intensities. The experimental EPR spectra were numerically decomposed into three components reflecting contributions of three different radicals (R1-R3) generated by ionizing ...
Barták M - - 2004
The effect of high light on spatial distribution of chlorophyll (Chl) fluorescence parameters over a lichen thallus (Umbilicaria antarctica) was investigated by imaging of Chl fluorescence parameters before and after exposure to high light (1500 micro mol m (-2) s (-1), 30 min at 5 degrees C). False colour images ...
Fujita Yoshihiko - - 2004
The fluorescence emitted at 710 nm by Phaeodactylum tricornutum (F(710)) was characterized. Development of F(710) was found to be regulated by the quality of light needed for algal growth: weak red light absorbed mainly by Chl a induced its development, and weak blue-green light absorbed mainly by fucoxanthin and Chl ...
Czepita Damian - - 2004
BACKGROUND: The purpose of our study was to determine if the development of refractive errors night be associated with exposure to light emitted by incandescent or fluorescent lamps. MATERIAL/METHODS: 3377 students from elementary schools, junior high schools and high schools were examined, aged 6-19 years. Visual acuity was measured, and ...
D'Haese David - - 2004
Nonlinear regression analysis (NLR) is applied to quantify the dynamic response of non-photochemical fluorescence quenching (NPQ) of Trifolium repens cv. Regal upon dark to light transition. Commonly, only steady-state levels of NPQ are evaluated, ignoring transient kinetics. Experimental NPQ kinetics are fitted best with a sum of two functions: a ...
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