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Results 501 - 550 of 828
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Pinto L S - - 2004
The effects of varying inoculum age and production scale upon the morphology and viability of Streptomyces clavuligerus were studied by analyzing visible and fluorescent light images acquired throughout pilot-plant and pre-industrial scale fermentations. Changes in production scale reveal that in 5 m(3) fermentors, the maximum hyphal area obtained is double ...
Dharmadhikari A - - 2004
We demonstrate highly efficient white light generation by focusing 45 fs long pulses of 800 nm laser radiation with 1 mJ energy onto a 10 cm long barium fluoride crystal. The entire wavelength band from 400-1000 nm was generated with efficiency greater than 40%. We also observe multiphoton absorption induced ...
Entcheva Emilia - - 2004
Tracking spatial and temporal determinants of cardiac arrhythmogenesis at the cellular level presents challenges to the optical mapping techniques employed. In this paper, we describe a compact system combining two nontraditional low-cost solutions for excitation light sources and emission filters in fluorescence measurements of transmembrane potentials, Vm, or intracellular calcium, ...
Lai Chee-Kong - - 2004
A portable system using light-induced fluorescence technology (LIF) was development as an analytical tool for on-line monitoring of various manufacturing process applications. The LIF system was verified in several laboratory scale process applications specifically in noninvasive real-time observations of blend kinetics in tumbler blenders. This technology, through careful selection of ...
Kasteleijn-Nolst Trenité Dorothée G A - - 2004
People of all ages, but especially children and adolescents, are increasingly exposed to visual stimuli. Typical environmental stimuli that can trigger epileptic seizures in susceptible persons are televisions (TVs), computers, videogames (VGs), discothèque lights, venetian blinds, striped walls, rolling stairs (escalators), striped clothing, and sunlight reflected from snow or the ...
Ferrari G - - 2003
We report the direct frequency measurement of the visible 5s(2) 1S0-5s5p 3P1 intercombination line of strontium that is considered a possible candidate for a future optical-frequency standard. The frequency of a cavity-stabilized laser is locked to the saturated fluorescence in a thermal Sr atomic beam and is measured with an ...
Yu Bing - - 2003
The purpose of this study was to compare the between-day repeatability of the knee kinematics and kinetics in stair climbing and level walking among three marker sets: the Helen-Hays marker set with some markers on well-defined bony landmarks and some on not well-defined locations on soft tissues, the modified Helen-Hays ...
Francois Patrice - - 2003
Microarrays have emerged as potential tools for bacterial detection and identification. Given their high parallelism, they might represent a breakthrough in current diagnostic methods, provided they can be coupled to simplified labeling protocols and detected with adequate sensitivities. We describe here a technique to directly label total bacterial RNA, thus ...
Siddiqi M A - - 2003
We describe the design, construction and testing of a prototype device that allows the direct visualization by eye of far-red and near-infrared (NIR) fluorescence through an optical microscope. The device incorporates a gallium arsenide (GaAs) image intensifier, typically utilized in low-light or 'night vision' applications. The intensifier converts far-red and ...
Mortensen Grith - - 2003
The effects of exposure of slices of Havarti cheeses to monochromatic light of wavelengths 366 nm, 405 nm, and 436 nm, respectively, were studied by tristimulus colorimetry, solid-phase microextraction gas chromatographic analysis of volatiles, and open-end fluorescence spectroscopy. Having determined the photon fluxes of the three wavelengths by ferrioxalate actinometry, ...
Jaiswal Jyoti K - - 2003
The wavelength of light imposes a physical limit of approximately 400 nm on the maximum resolution that can be achieved using light microscopy. This unit will describe the use of total internal reflection fluorescence microscopy (TIR-FM), or evanescent wave microscopy, an approach that partially overcomes this physical limit and permits ...
Bain A J - - 2003
A new approach to time-resolved fluorescence spectroscopy based on stimulated emission depletion (STED) of two-photon excited states is presented. Combined with time-resolved detection, STED can circumvent orientational averaging constraints and spontaneous emission selection rules inherent in all conventional techniques. Applications of STED to the study of molecular probe dynamics are ...
Pan Yong-Le - - 2003
We demonstrate a proof-of-concept optical spectroscopic system for bioaerosol-particle fluorescence detection, in which a pulsed high-power laser is replaced by a highly compact linear array of sequentially fired light from blue light-emitting diodes. The results suggest that low-cost, compact optical aerosol detection may be feasible with the contemporary emergence of ...
Boere I A - - 2003
Experimental therapies for Barrett's esophagus, such as 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT), aim to ablate the premalignant Barrett's epithelium. However, the reproducibility of the effects should be improved to optimize treatment. Accurate irradiation with light of a proper wavelength (633 nm), fluence and fluence rate has shown to be ...
Mayr Torsten - - 2003
A cross-reactive array in a micro titer plate (MTP) format is described that is based on a versatile and highly flexible scheme. It makes use of rather unspecific metal ions probes having almost identical fluorescence spectra, thus enabling (a) interrogation at identical analytical wavelengths, and (b) imaging of the probes ...
Nakajima Nobuyoshi - - 2003
The acylated plant pigments synthesized by lipase-catalyzed transesterification with aromatic acids were compared in respect of their light-resistance and radical-scavenging ability. With both the flavonols and anthocyanins, their acylated derivatives were more stable against illumination with fluorescent light than their non-acylated glucosides. Their radical-scavenging ability partially decreased or was retained ...
Vredenberg Wim J - - 2003
Fluorescence induction curves (F(t)) in low intensity 1s light pulses have been measured in leaf discs in the presence and absence of valinomycin (VMC). Addition of VMC causes: (i) no effect on the initial fluorescence level Fo and the initial (O-J) phase of F(t) in the 0.01-1 ms time range. ...
Mujat Claudia - - 2003
A basic understanding of the light-scattering processes that take place inside the dental tissue (either sound or carious) is obtained both with measurements of the photon path-length distribution of light inside such media and with Monte Carlo simulations. Furthermore, the following is investigated: the correlations between different momenta of the ...
Sudworth Caroline D - - 2003
We describe a technique designed to monitor the fluorescence dynamics of photosensitizers used in photodynamic therapy (PDT) at micrometer-scale locations within individual formalin-fixed cells. The accumulation of protoporphyrin IX (PpIX) within keratinocytes and fibroblasts. following incubation with 5-aminolaevulinic acid (ALA), is shown to be dependent upon both incubation time and ...
McGreevy James M - - 2003
BACKGROUND: We examined the usefulness of a new agent in the mapping and dissection of inguinal lymph nodes in the pig. Cy5-cobalamin bioconjugate is blue under visible light and fluoresces brilliant red with laser stimulation. The wavelength of the emitted red light is sufficiently long that it is visible through ...
Houston Jessica P - - 2003
The development of near-infrared fluorescent contrast agents and imaging techniques depends on the deep penetration of excitation light through several centimeters of tissue and the sensitive collection of the re-emitted fluorescence. In this contribution, the sensitivity and depth penetration of various fluorescence-enhanced imaging studies is surveyed and compared with current ...
Zaharieva Ivelina - - 2003
A method for data acquisition based on recording of light signal from a conventional phophoroscope fluorometer with high-speed digitalization is proposed to extract more information from a delayed chlorophyll a fluorescence (DF) signal. During the signal processing from all points registered by the fluorometer, we obtain simultaneously a large number ...
Utzinger Urs - - 2003
The most common way to detect disease is by visual inspection of the suspect tissue. However, the human eye is not optimized for this task because the perceived spectrum of light is divided into three channels, all of which have overlapping spectral sensitivity curves. Here, we present new methods to ...
Witting Michael D - - 2003
STUDY OBJECTIVE: Despite its common clinical use, the range of normal pupillary size has been described only crudely. The objective of this report is to describe the distribution of normal pupillary sizes in 2 light conditions that are available in clinical settings. METHODS: Pupillary size measurements were taken from healthy ...
Maul Holger - - 2003
OBJECTIVE: The purpose of this study was to investigate gestational changes of cervical light-induced fluorescence, an index of cross-linked collagen, and the relationship between light-induced fluorescence and the time-to-delivery interval. STUDY DESIGN: Fifty patients were included in one of two groups. (1) Twenty-one healthy pregnant women without signs of labor ...
Heyes Derren J - - 2003
The light-driven enzyme NADPH:protochlorophyllide oxidoreductase (POR) catalyzes the reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide), a key regulatory step in the chlorophyll biosynthesis pathway. As POR is light activated, it allows intermediates in the reaction pathway to be observed by initiating catalysis with illumination at low temperatures, a technique that ...
Wilcoxen Steven E - - 2003
In the US Environmental Protection Agency methods for sediment toxicity testing, the light regimen is specified as a 16:8 light dark cycle with 500-1000 lx. The potential for photoinduced toxic effects from this requirement is evaluated. Hyalella azteca were exposed to fluoranthene in both water only and sediment to examine ...
Malik Vikas - - 2002
The present study was carried on forty-five patients of confirmed hypothyroidism. Complete clinical examination and laboratory investigations were done regarding audiological and vestibular system. It was found that hypothyroidism affects the ear at multiple sites producing various types of hearing impairment viz. conductive, sensorineural and mixed. Vestibular system was found ...
Woodruff Michael L - - 2002
A 10 microm spot of argon laser light was focused onto the outer segments of intact mouse rods loaded with fluo-3, fluo-4 or fluo-5F, to estimate dark, resting free Ca(2+) concentration ([Ca(2+)](i)) and changes in [Ca(2+)](i) upon illumination. Dye concentration was adjusted to preserve the normal physiology of the rod, ...
Bell Marcus G - - 2002
The method of polarized fluorescence depletion (PFD) has been applied to enhance the resolution of orientational distributions and dynamics obtained from fluorescence polarization (FP) experiments on ordered systems, particularly in muscle fibers. Previous FP data from single fluorescent probes were limited to the 2(nd)- and 4(th)-rank order parameters, <P(2)(cos beta)> ...
Sinha Rajeshwar P - - 2002
The effect of UV and visible light on cyanobacteria was determined at the cellular level by means of epifluorescence and confocal microscopy techniques. These methods allow the examination of light effects in spatial resolution. Series of measurements were performed to determine the effect of different light qualities and quantities on ...
Mortensen Grith - - 2002
Light-induced oxidation in Havarti cheese (38% fat) stored in the dark and exposed to fluorescent light was evaluated by an array of chemical, physical, and spectroscopic methods. Light-induced changes were noticeable already after short exposure times (<12 h). A clear differentiation between samples stored in the dark and samples exposed ...
El Aatmani Mohamed - - 2002
The stability of dacarbazine in commercial glass vials and polyvinyl chloride (PVC) bags in various storage conditions and the emergence of 2-azahypoxanthine, a major degradation product possibly linked with some adverse effects, were studied. Triplicate samples of reconstituted (11 mg/mL) and diluted (1.40 mg/mL) dacarbazine admixtures were prepared and stored ...
Rajagopal S - - 2002
The activity of light-induced oxygen consumption, absorption spectra, low temperature (77 K) chlorophyll fluorescence emission and excitation spectra were studied in suspensions of photosystem (PS) I submembrane particles illuminated by 2000 microE m(-2) s(-1) strong white light (WL) at 4 degrees C. A significant stimulation of oxygen uptake was observed ...
Wold J P - - 2002
The purpose of this paper is to demonstrate the potential of solid-sample fluorescence spectroscopy in nondestructive assessment of light-induced oxidation in different dairy products such as Swiss cheese, cream cheese, and sour cream. Analytical and quantitative spectral properties of fluorescence were elucidated by use of principal component analysis with designed ...
Yamano Yukio - - 2002
This study examined the effects of storage conditions such as time course, temperature, fluorescent light, and darkness on the components and antibacterial activity of formalin guaiacol (FG) used in endodontic treatment. We measured the quantities of formaldehyde and guaiacol in FG and antibacterial activities against Staphylococcus aureus, Porphyromonas gingivalis, and ...
Richardson Andrew D - - 2002
Spectral reflectance and chlorophyll fluorescence are rapid non-invasive methods that can be used to quantify plant stress. Because variation in ambient light (e.g., diurnal patterns of solar radiation) may have a confounding effect on these measurements, branches are often excised in the field and then measured under controlled conditions in ...
Trissel Lawrence A - - 2002
The physical and chemical stability of fenoldopam as the mesylate salt were studied. Test samples of fenoldopam mesylate, with fenoldopam concentrations ranging from 4 to 300 micrograms/mL, were prepared in polyvinyl chloride (PVC) bags of 5% dextrose injection and 0.9% sodium chloride injection and were stored at 4 degrees C ...
GrudziƄski Wojtek - - 2002
Light-induced chlorophyll a (Chl a) fluorescence quenching was studied in light-harvesting complex of photosystem II (LHCII). Fluorescence intensity decreased by ca. 20% in the course of 20 min illumination (412 nm, 36 micromol m(-2) s(-1)) and was totally reversible within 30 min dark adaptation. The pronounced quenching was observed only ...
Pretty I A IA Department of Clinical Dental Sciences, The University of Liverpool, Edwards Building, Daulby Street, Liverpool L69 3GN, UK. - - 2002
The use of optical methods in the diagnosis of early caries is developing rapidly. The introduction of the quantitative light-induced fluorescence (QLF) device has promised the use of a quantifiable technique in vivo. This study describes the effect that ambient light has upon the reliability of QLF analyses. Using human ...
Dijkman Nicole A - - 2002
The marine diatom Thalassiosira weissflogii was cultured under a light regime simulating the daily rise and fall of the sun. The light regime caused a daily cycle in non-photochemical quenching. Remarkable were the changes in fluorescence directly after a light-to-dark transition that occurred in addition to the changes induced by ...
Andrasko Jan - - 2002
A method for comparison of the relative age of ink entries written by the same ballpoint pen on documents stored in darkness is presented. Inks were extracted from the document and analyzed by HPLC (high performance liquid chromatography). On aging, changes in the chemical composition of the inks were noted. ...
Oberyszyn Andrew S - - 2002
The routine operation of a flow cytometer generates aerosols, and most commercially available instrument are not designed to be 100% effective in their elimination. Aerosols are a concern for operators as well as for others in the facility because of the potential for exposure to contamination, especially during sorting of ...
Yamawaki Yoshifumi - - 2002
The tachinid fly Exorista japonica is a parasitoid of many kinds of lepidopterous larvae. After encountering a suitable host, the fly pursues the crawling larva on foot using visual cues to guide it. To investigate the visual control of host pursuit, we observed and videotaped pursuits of a host, the ...
Koshiba Mamiko - - 2002
It has been reported that light exposure to one eye induces functional lateralization, which can be inverted by exposing the opposite eye to the light. However, the anatomical basis of the functional inversion by the light has not been shown. To address this issue, we labeled cells in the dorsolateral ...
Whited L J - - 2002
To determine the effects of light exposure on vitamin A degradation and on light-oxidized flavor development, samples of whole, reduced fat, and nonfat milk were exposed to fluorescent light (either 1000 or 2000 lx) at time intervals of 2, 4, 8, or 16 h. Measurable vitamin A losses occurred at ...
Smith Petra Wilder - - 2002
Over the past decades, laser use in medicine has expanded from its initial application as a light-based scalpel to a plethora of clinical uses, ranging from surgical treatment through composite polymerization, dental ablation, vision correction, and skin resurfacing to diverse diagnostic modalities. Recently, the concept of light-based diagnostics and therapy ...
Hedley John D - - 2002
Coral reef communities face unprecedented pressures on local, regional and global scales as a consequence of climate change and anthropogenic disturbance. Optical remote sensing, from satellites or aircraft, is possibly the only means of measuring the effects of such stresses at appropriately large spatial scales (many thousands of square kilometres). ...
Cajánek M - - 2002
Using 77 K chlorophyll a (Chl a) fluorescence spectra in vivo, the development was studied of Photosystems II (PS II) and I (PS I) during greening of barley under intermittent light followed by continuous light at low (LI, 50 mumol m(-2) s(-1)) and high (HI, 1000 mumol m(-2) s(-1)) irradiances. ...
Zena R - - 2001
A porcelain system has been developed that combines dental-ceramic engineering and fiber-optic technology. This system involves cutting-edge technology that results in optical properties that emulate nature closer than ever before. The enhanced opalescence and fluorescence, combined with optical clarity, results in color-reactive porcelain that looks natural and esthetic in any ...
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