Search Results
Results 751 - 800 of 828
< 7 8 9 10 11 12 13 14 15 16 17 >
Nalin C M - - 1983
N-(1-Anilinonaphthyl-4)maleimide (ANM) has been used to modify coupling factor 1 (CF1), the terminal coupling factor of photophosphorylation in chloroplasts. As with other monofunctional maleimides, incubation of thylakoids with ANM in the light, but not in the dark, causes energy transfer inhibition of photophosphorylation. In the dark, sites on both the ...
Satoh K - - 1983
In the red alga Porphyra perforata, the level of chlorophyll fluorescence in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) decreased during illumination of the thallus. The results showed that: (a) this decay was related to the photooxidative activity of photosystem I; (b) Q, the primary electron acceptor of photosystem II, became oxidized ...
Kasprzak A - - 1982
The fluorescence of bovine pancreatic trypsin inhibitor (BPTI) is due to one or more of its four tyrosine residues. Observations of the stationary polarization of the fluorescence over a large range of temperatures and viscosities permit the demonstration of at least three modes of tyrosine rotation, and perhaps an ultrafast ...
Koper G J - - 1982
The application of arc lamps to flow cytometers is discussed and epiillumination for jet-in-air cell sorters is introduced. An epiilluminator/detector unit equipped with a mercury arc lamp constructed for a commercially available cell sorter is described. Experiments in which laser and mercury arc lamp illumination were compared show that the ...
Murgatroyd L B - - 1982
Paraffin sections of kidney, lung and oesophagus containing Aspergillus sp., Cryptococcus neoformans and Candida sp. were taken from human post mortem material and from the marmoset Callithrix jacchus. Sections were stained for 1-5 min in buffered 2-hydroxystilbamidine isethionate containing sodium metabisulphite after pre-oxidation in 1 per cent aqueous periodic acid. ...
Laszlo I - - 1982
Various histological structures from rat brain prepared by the formaldehyde induced fluorescence method can be visualized with the help of illumination in tungsten light by using phase contrast condenser (without phase contrast objective). The procedure was found useful for the location of areas to be studied by subsequent fluorescence microscopy ...
Fonger W H - - 1982
The tubular fluorescent lamp is approximated by two flat parallel phosphor layers excited internally. Using single-layer formulas from Parts 1 and 2, formulas for the tube losses and light output are obtained. An approximate formula due to Butler agrees with the tube light output here when the phosphors are very ...
Vierstra R D - - 1982
The vacuoles of lower epidermal strips from Vicia faba exhibit an intrinsic green fluorescence when incubated in alkaline buffers. Using an alkaline-induced absorbance change as a spectrophotometric assay, the major pigment responsible for this fluorescence was isolated and identified as the flavonoid: kaempferol 3-O-galactoside, 7-O-rhamnoside. The aqueous absorption maxima were ...
Keith I M - - 1982
We describe a modified and standardized quantitative FIF procedure for producing fluorophores and measuring emission intensity of serotonin-containing neuroepithelial bodies (NEB's) in the rabbit lung. This technique, using epifluorescence, was reproduced without significant differences between control groups. Important considerations for reproducibility were: using the same humidity (80% RH) and reaction ...
Ritter M A - - 1981
Cell survival and induction of endonuclease-sensitive sites in DNA were measured in human fibroblast cells exposed to fluorescent light or germicidal ultraviolet light. Cells from a xeroderma pigmentosum patient were hypersensitive to cell killing by fluorescent light, although less so than for germicidal ultraviolet light. Xeroderma pigmentosum cells were deficient ...
Klebe R J - - 1981
Optical techniques are described which permit one to analyze two-dimensional electrophoretic gels in a fashion which is analogous to the one-dimensional spectroscopy of solutions. In the methods described, an electrophoretic gel is irradiated with monochromatic light and isozyme patterns are detected by the absorption of light or the fluorescent emission ...
Sideris E G - - 1981
Little information is available on the effect of visible light from commercial fluorescence lamps, commonly used in the treatment of neonatal hyperbilirubinemia, on parameters related to genetic damage in eucaryotic cells. The present study was undertaken to determine whether or not visible light of different wavelengths had any differential effects ...
Csatorday K - - 1981
In vivo fluorescence studies of Cyanidium caldarium mutants grown in the dark in dextrose-containing media have shown that these organisms accumulate protoporphyrin IX. In the dark the accumulated protoporphyrin IX is gradually turned into a metalloporphyrin, Zn protoporphyrin. In the light, in the chlorophyll-lacking mutant GGB, both compounds are degraded ...
Rice G E - - 1980
Slow fluorescence transients in Chlamydomonas reinhardi arise after transitions from high light intensities to low light or dark conditions. Characteristics of the newly described transient phenomena include: (a) A slow biphasic decrease in fluorescence yield occurs in the dark, followed by an even slower, hour long, increase in fluorescence. (b) ...
Loken M R - - 1980
A simple yet effective method of testing optical filters under normal operating conditions on a Fluorescence Activated Cell Sorter is described. The spectral characteristics of three filters are compared to demonstrate the methods of determining which filter is the best in a particular situation. These tests include determining the efficiency ...
Hyvärinen L - - 1980
Indocyanine green (ICG) fluorescence angiography has been further refined for use in both laboratory and clinical investigations. In the present modification of the Zeiss fundus camera all lenses except the aspherical objective lens have been specially antireflection coated to increase light transmission in the spectral region around 800 nm. A ...
Boldt M - - 1980
The construction of a microscope photometer using prefabricated elements is described. To illuminate the tissue, a Leitz Ultropac is applied. To enlarge the wavelength range, its illuminating glass lens is replaced by an Acryl glass zonal lens. Two separate light channels with separate lamps, monochromators and photomultipliers allow the measurement ...
Godik V I - - 1980
The ratio between the intensities of delayed and prompt fluorescence was studied for different photosynthetic objects under different conditions by modulation method. The method is based on excitation of luminescing objects by light, modulated harmonically, and on a combined study of phase shifts and demodulation coefficients of the luminescence as ...
Osol J G - - 1980
Four replicate experiments were conducted to determine the effects of pinealectomy and environmental lighting on testes and comb weights in the broiler cockerel. Birds were housed in brooder batteries under a 14L:10D fluorescent white light regime for 2 weeks and then allotted to light-controlled chambers. Surgery was performed when the ...
Smalley K N - - 1980
Two fluorescent materials have been localized in the adult firefly light organ by fluorescence microscopy. One of these is located in photocyte granules, has a maximum emission between 510 and 540 nm, is more fluorescent in basic than acidic solution, and is unstable in ultraviolet light, phosphomolybdic acid, and potassium ...
Kennedy A R - - 1980
Fluorescent light induced a dose-dependent malignant transformation in mouse C3H10T1/2 cells. A plateau in the dose-response curve for transformation was correlated with that observed with ultraviolet light exposure. The similarity in the two dose-response patterns suggests that similar molecular processes may be involved in the induction of malignant transformation by ...
Dunlap J C - - 1980
Dinoflagellate luciferin has been found to crossreact and emit light with euphausid photoprotein; and euphausid fluorescent substance gives luminescence with dinoflagellate luciferase. Luciferin and the fluorescent substance, both highly unstable and fluorescent compounds, are biochemically similar but not identical. Preliminary spectral and chemical data suggest that both compounds contain an ...
Silberstein B R - - 1980
The flying spot fluorometer/reflectometer for flavoprotein (Fp) was used in the present study in order to evaluate energy metabolism in the anesthetized gerbil brain. This model was exposed to various conditions, such as anoxia, spreading depression, and ischemia. The fluorescence and reflected light were analyzed in terms of intensities of ...
Franke H - - 1980
Surface fluorescence of reduced pyridine nucleotide (PN) was recorded continously with a DC fluorormeter and correlated with changes in experimental conditions. As a light source for fluorescence excitation, an Hg arc lamp with a 340-375 nm filter in front was used; the fluorescence response of reduced PN was measured at ...
Schauenstein K - - 1980
In general there exist two possibilities to obtain quantitatively information in immunohistochemical work: (1) Titration of an antibody of defined specificity and concentration on different antigenic substrates. (2) The measurement of the "specific signal" of the marker molecule used for the visualization of the specific fixation of antibody to the ...
Krell K - - 1980
Compared to the basis of equal exposure, in joules per square meter (J/m2) the mutagenic and toxic effects in L5178Y mouse lymphoma cells of radiation emitted by some fluorescent lamps and a sunlamp are quantitatively similar to solar radiation effects at the earth's surface. When the relative intensities of radiation ...
Ohad I - - 1980
Several lines of evidence indicate that allophycocyanin is the previously unidentified "phycochrome" observed in extracts of blue-green algae.Fractions containing phycoerythrin, phycocyanin, and allophycocyanin and exhibiting light-induced absorbance changes were prepared from extracts of Nostoc muscorum and Fremyella diplosiphon by isoelectric focusing. Illumination of such fractions with red light (650 nanometers) ...
Binnie C D - - 1979
Fluorescent tubes flash at twice the mains frequency (100 Hz in Europe). With aging, 50-Hz brightness modulation appears. A survey of tubes used in our institute showed that 42% exhibited brightness modulation up to a depth of 20% or occasionally 30%. The effects of fluorescent lighting on the EEGs of ...
Bollinger A - - 1979
An intravital fluorescence videomicroscopy technique is described in an attempt to develop non-invasive methods for the study of transcapillary exchange in human physiology and clinical medicine. The apparatus used consists of a Ploemopak incident light fluorescence microscope and a low light level television camera with linear output. After intravenous bolus ...
Twomey L L Western Australian Institute of - - 1979
Two new instruments, a lumbar spondylometer and a rotameter, for the measurement of sagittal and horizontal plane motion in the lumbar spine respectively, are described. They enable the clinician to more accurately measure and chart the progress of patients with low back problems.
Ang C Y - - 1979
Pyridoxine.HCl, pyridoxal.HCl, and pyridoxamine.2HCl solutions were exposed to several laboratory light treatments, and the resulting vitamin retentions were determined by the AOAC microbiological method. The 5 treatments compared were total darkness, regular laboratory light, low actinic glass protection, yellow incandescent light, and golden fluorescent light. All treatments were imposed for ...
Allen C - - 1979
Photodegradation of riboflavin in 50-ml samples of fluid milks exposed to fluorescent light (2690 lux) followed first-order reaction kinetics, and the reaction rate (s-1) averaged 1.86 x 10(-5) in skim milk and 1.47 x 10(-5) in whole milk. Additional evidence led us to conclude that photodegradation of riboflavin proceeds prior ...
van der Ploeg M - - 1979
Bright microscopic images against a dark background can be originating not only from fluorescence, but also from selective reflection. Selective reflection or scattering of visible light in microscopic preparations can be used for the visualization of sometimes otherwise barely distinguishable material. The images obtained superficially resemble those from fluorescence microscopy. ...
Ji S - - 1979
Three-way light guides containing one or more strands of 25-micron or 80-micron diameter optical fibers in each channel have been constructed and used to measure the NADH fluorescence and UV reflectance from mitochondrial suspensions, the perfused, hemoglobin-free rat liver, and the perfused beating interventricular septum of the rabbit. The optical ...
Baguet F - - 1979
1. Isolated photophores of Porichthys exposed to u.v. light (365 nm) exhibit a green fluorescence localized in the photocytes and a bluish fluorescence originating from the lens-like body. 2. The luminescence of photophores evoked by epinephrine, nor-epinephrine or potassium cyanide decreases with the intensity of the green fluorescence of the ...
Andersen B R - - 1978
The estimated light emission spectrum was determined for a singlet oxygen (1O2)-producing system, NaOCl + H2O2, alone and in the presence of tryptophan and bovine serum albumin. Tryptophan and bovine serum albumin caused a decrease in the red emission of 1O2 and an increase in the amount of shorter wavelength ...
O'Leary K D - - 1978
Seven first-grade children with conduct disorders and/or hyperactivity attended full-day sessions at a laboratory school classroom. During an 8-week period, the classroom lighting conditions alternated at the end of each week. During odd-numbered weeks, the classroom was illuminated by a standard cool-white fluorescent system. On even-numbered weeks, illumination was a ...
Jacobson E D - - 1978
Unfiltered broad spectrum radiation emitted by black light, cool white, and black light blue fluorescent lamps and a sunlamp, is both toxic and mutagenic to L5178Y mouse lymphoma cells when the cells are irradiated in phosphate-buffered saline. The increase in mutant frequency seen after exposure of the cells is linear ...
Malkin S - - 1978
1. Using a phosphoroscope, delayed luminescence and prompt chlorophyll fluorescence from isolated chloroplasts have been compared during the induction period. 2. Two distinct decay components of delayed luminescence were measured a "fast" component (from approximately 1 ms to approximately 6 ms) and a "slow" component (at approximately 6 ms). 3. ...
Harnischfeger G - - 1978
Short illumination with white light of dark-maintained Anacystis nidulans prior to immersion in liquid nitrogen resulted in a marked change of fluorescence emission characteristics at 77 K. The fluorescence of Photosystem II-associated membrane bound pigments increases, while the emission due to phycobilins decreases. This effect seems to be due to ...
Harrison R M - - 1978
A system for obtaining anatomical cross-sections for treatment planning using a radiotherapy simulator is described. A fluorescent screen is viewed by a low light level Isocon television camera and the video signal is digitized and stored. Many projections of the phantom are obtained by rotating the simulator gantry. A convolution ...
Hapner S J - - 1978
Tissue slices from the roots and seeds of sanifoin (Onobrychis viciifolia, Scop.) exhibit bright autofluorescence when illuminated with blue (495 nm) light. This autofluorescence is indistinguishable from the fluorescence emission of fluorescein, the commonly used fluorochrome in immunohistochemical staining procedures. Rhodamine isothiocyanate, when coupled to immunoglobulin, and excited with green ...
Rayner D M - - 1978
The fluorescence decay profiles have been determined for a number of light, crude, and heavy oils under ideal laboratory conditions to assess their utility in the remote characterization and identification of oil spills using remote laser fluorosensors. The fluorescence decay of light and crude oils can best be described by ...
Walters J P - - 1977
Spark discharge is shown to be a cyclic process of energy dissipation, with one spark in a time-connected train influenced by its relation to predecessor sparks. Spectroscopic instruments having temporal, spatial, and spectral resolution indicate that the light emission is highly ordered with cylindrical symmetry about the current-conducting spark channel. ...
Alberti P W - - 1977
Hearing loss in the elderly is an extremely common handicap which must be assessed together with multiple sensory handicaps. The handicap produced is more than a peripheral loss of hearing acuity; it is a complex amalgam of end organ and neurological deficits, including the inability to inhibit unwanted sound as ...
Changaris D G - - 1977
Fluorescent microspectrophotometry using dichroic mirror vertical epi-illumination of tissue sections stained with the PAS reaction (periodic acid and pararosaniline Schiff reagent) provides a measure of the relative concentration of 1:2 glycols within and between tissue sections. In PAS reacted sections of agarose gel, pararosaniline Schiff fluorescence increases linearly as the ...
Hood J W - - 1977
A new Australian Standard "AS 1765-1975 Artificial Lighting for Clinical Observation" has recently been published. This specifies the quality of light necessary to accurately assess a patient's colour. The physical principles and terminology used in modern lighting are discussed, and the experimental work on which the new Standard is based ...
Harris L - - 1976
The flucrescence decay of Chlorella pyrenoidosa has been investigated under a variety of conditions in the picosecond and nanosecond time regions. Most of the fluorescence is accounted for by an expression of the form I(t) = I0exp-(At+Bt1/2) though an additional exponential term is required to include a weak component of ...
Harbig K - - 1976
A modification of the methods is described which makes it possible to measure pyridine nucleotide fluorescence from the brain cortex in vivo without interference from movement and hemodynamic artifacts. Movement artifacts were eliminated by the use of a window technique. Fluorescence changes due to changes in hemoglobin oxygenation have been ...
Campillo A J - - 1976
New data on intensity-dependent lifetimes indicate that all previous in vivo fluorescence studies of chlorophyll by picosecond techniquies must be reinterpreted. Anomalously short lifetimes result from high-intensity effects due to exciton-excition annihilation processes. Measurements in Chlorella pyrenoidosa with single-pulse, low-intensity excitation indicate a longer "true" lifetime of 650 +/- 150 ...
< 7 8 9 10 11 12 13 14 15 16 17 >