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Topic: Fluorescence


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In the News (Sat 15 Jun 19)

  
  Fluorescence - LoveToKnow 1911
Stokes found that the fluorescent light is not homogeneous, for on reducing the incident rays to a narrow band of homogeneous light, and examining the dispersed beam through a prism, he found that the blue light consisted of rays extending over a wide range of refrangibility, but not into the ultra-violet.
Fluorescence is closely allied to phosphorescence, the difference consisting in the duration of the effect after the exciting cause is removed.
The phenomenon of fluorescence can be utilized for the purpose of illustrating the laws of reflection and refraction in lecture experiments since the path of a ray of light through a very dilute solution of a sensitive substance is rendered visible.
www.1911encyclopedia.org /Fluorescence   (1957 words)

  
 Olympus Microscopy Resource Center: Specialized Microscopy Techniques - Fluorescence Microscopy
Fluorescence illumination and observation is the most rapidly expanding microscopy technique employed today, both in the medical and biological sciences, a fact which has spurred the development of more sophisticated microscopes and numerous fluorescence accessories.
Fluorescence is the property of some atoms and molecules to absorb light at a particular wavelength and to subsequently emit light of longer wavelength after a brief interval, termed the fluorescence lifetime.
Fluorescence Microscopy of Cells in Culture - Serious attempts at the culture of whole tissues and isolated cells were first undertaken in the early 1900s as a technique for investigating the behavior of animal cells in an isolated and highly controlled environment.
www.olympusmicro.com /primer/techniques/fluorescence/fluorhome.html   (2351 words)

  
  Fluorescence - Wikipedia, the free encyclopedia
Fluorescence is a luminescence that is mostly found as an optical phenomenon in cold bodies, in which the molecular absorption of a photon triggers the emission of a lower-energy photon with a longer wavelength.
Fluorescence is named after the mineral fluorite, composed of calcium fluoride, which exhibits this phenomenon.
Fluorescence quantum yield are measured by comparison to a standard with known quantum yield; the quinine salt, quinine sulfate, in a sulfuric acid solution is a common fluorescence standard.
en.wikipedia.org /wiki/Fluorescence   (1552 words)

  
 Nikon MicroscopyU: Fluorescence Microscopy
Fluorescence Illumination in Stereomicroscopy - The application of stereomicroscopes for GFP observation is now so prevalent that stereo fluorescence illuminators are more frequently referred to as GFP illuminators, even though they can be utilized for many other applications in both the life sciences and the electronics manufacturing industry.
The fluorescence illumination reveals which organisms are producing the fluorescent protein and the stereoscopic vision coupled to a large field of view and ample working distance enables observers to conduct experiments with forceps, pipettes, or micromanipulators.
Typically, the fluorescence illuminator consists of a xenon or mercury arc lamp contained in an external lamphouse that is attached to the microscope via an intermediate tube (or vertical illuminator) positioned between the microscope zoom body and observation tubes.
www.microscopyu.com /articles/fluorescence   (1980 words)

  
 Invitrogen - Molecular Probes - Fluorescence Tutorial
Fluorescence is also important in the detection and quantitation of nucleic acids and proteins in gel electrophoresis, microarrays, and fluorescence spectroscopy.
You are probably already familiar with fluorescence as a property of some substances that "glow in the dark".
With sophisticated microscopes and instruments, it is possible to detect, image, and measure the amount of fluorescence in samples as small as individual cells, and with multiple fluorescent colors.
probes.invitrogen.com /resources/education   (154 words)

  
 Center for Fluorescence Spetroscopy
For the past 15 years the CFS by the P41 mechanism, has advanced the technology for fluorescence and its applications to the biosciences.
Considerable progress has been made in the CFS and elsewhere in areas such as probe chemistry, multi-photon excitation, steady state imaging, time-resolved imaging, genetically engineered probes, and single molecule detection.
The role of the CFS has typically been to develop the fundamental chemistry, instruments or analysis methods which are then applied to areas such as fluorescence sensing, genetic analysis and cellular imaging.
cfs.umbi.umd.edu   (171 words)

  
 Fluorescence
Fluorescence is a process distinct from incandescence (i.
Heating is generally detrimental to the process of fluorescence, and most substances, when fluorescing, produce very little heat.
Today’s new generation of instruments are using luminescence and fluorescence for detection simultaneously and combining them.
www.bertholdtech.com /ww/en/pub/bioanalytik/biomethods/fluor.cfm   (251 words)

  
 The Scientist : Making the Most of Fluorescence
Fluorescence lifetime imaging microscopy and spectral imaging complement conventional techniques
Open a life science journal, and you're bound to see photomicrographs in shades of red, yellow, green, and blue.
Recommend us to your librarian and get online access through your place or work or study.
www.the-scientist.com /article/display/15428   (163 words)

  
 Fluorescence Underwater
Besides coral recruitment, scientists are using NightSea equipment to study the ecology of coral fluorescence and to search for novel fluorescent proteins.
NightSea's blue light fluorescence technology is much smaller and less expensive than available underwater ultraviolet lights, and works just as well.
Mantis shrimp fluorescence - first time demonstrating a function for fluorescence in a marine animal, with a really cool video of a mantis shrimp spearing a fish!
www.nightsea.com /underwater.htm   (343 words)

  
 Olympus FluoView Resource Center: Fluorescence Lifetime Imaging
Multi-color staining with fluorescent dyes is actively used for observing the distribution of biological materials (such as proteins, lipids, nucleic acids, and ions) in the field of tissue and cell research.
In addition to multi-color staining, fluorescence lifetime imaging can also be utilized to visualize the factors that affect the fluorescence lifetime properties of the dye molecule, that is, the state of the environment around the molecule.
Frequency-domain FLIM - Fluorescence lifetime is calculated by measuring the phase shift of fluorescence and the reduction in its amplitude using a detector with a gain modulator when the laser used as the excitation light source is modulated (1 to 200 megahertz).
www.olympusfluoview.com /applications/flimintro.html   (951 words)

  
 Imaging Research Inc.: Fluorescence Imaging
Fluorescence is emitted when a fluorophore interacts with an incident photon (excitation).
BCECF fluoresces strongly at visible wavelengths, with an excitation peak at 503 nm and an emission peak at 525 nm.
Another option is to decrease fluorescence intensity at the brighter wavelength by using an ND filter mounted prior to the excitation filter.
www.imagingresearch.com /applications/Fluorescence.asp   (3004 words)

  
 Tutorial - Fluorescent Microscope Optics: C&L Instruments, Inc.
A fluorescent microscope also produces a magnified image of the sample, but the image is based on the second light source -- the light emanating from the fluorescent species -- rather than from the light originally used to illuminate, and excite, the sample.
In order to excite fluorescent species in a sample, the optics of a fluorescent microscope must focus the illumination (excitation) light on the sample to a greater extent than is achieved using the simple condenser lens system found in the illumination light path of a conventional microscope.
In a fluorescence microscope, a dichroic mirror is used to separate the excitation and emission light paths.
www.fluorescence.com /tutorial/fm-optic.htm#requirements   (1202 words)

  
 UTILITY AND LIMITATIONS OF CHLOROPHYLL FLUORESCENCE FOR THE DETERMINATION OF GROWTH LIMITATIONS IN TREES
Fluorescence measurements were taken over 30 seconds, with an incident light level of 800 micromoles per meter squared per second.
Fluorescence measurements were taken over 15 seconds, with an incident light level of 1000 micromoles per meter squared per second.
Fluorescence measurements were taken over 10 seconds, with an incident light level of 1000 micromoles per meter squared per second.
filebox.vt.edu /forestry/faculty/jopeters/sscfluor.htm   (2777 words)

  
 CHP - Molecular Fluorescence Spectroscopy   (Site not responding. Last check: )
Molecular fluorescence is the optical emission from molecules that have been excited to higher energy levels by absorption of electromagnetic radiation.
The main advantage of fluorescence detection compared to absorption measurements is the greater sensitivity achievable because the fluorescence signal has in principle a zero background.
The fluorescence is dispersed by another monochromator and detected by a photomultiplier tube.
www.chem.vt.edu /chem-ed/spec/molec/mol-fluo.html   (200 words)

  
 AGS-000 Ideal Cut Diamonds & Wholesale Diamond Price Guides
We do not inventory very many diamonds with fluorescence in our Private Reserve because we find that people buying a diamond on-line hesitate to purchase a fluorescent diamond because people tend to be afraid of what they can not see...
It is important to be aware of fluorescence and then to view the diamond to determine whether it's effect on the diamond is negative, positive, or not at all.
A diamond rated as having a fluorescence rating of None by the GIA or Inert by the AGS may exhibit a little fluorescence, but not enough to have any effect on the diamond in terms of visual performance.
www.niceice.com /fluorescence.htm   (1265 words)

  
 Cell Biology: Microscopy, Kent State University - Fluorescence Microscopy   (Site not responding. Last check: )
Fluorescence microscopy is used to detect structures, molecules or proteins within the cell.
In fluorescence microscopy, a cell is stained with a dye and the dye is illuminated with filtered light at the absorbing wavelength; the light emitted from the dye is viewed through a filter that allows only the emitted wavelength to be seen.
Among the common fluorescence dyes are fluorescein, which emits green light when exited with blue light and rhodamine, which emits a deep red fluorescence when excited by green-yellow light.
dept.kent.edu /projects/cell/fluoro.htm   (1613 words)

  
 The Application of Ultraviolet Fluorescence to Lithic Sourcing
Geological research into fluorescence proliferated in the 40's and early 50's, but subsequently, with the exception of mineralogy, most of the research addressed non-geological applications in chemistry, biology, and areas such as the textiles and paint industries.
Fluorescence is named for the mineral fluorite, which has a faint, yet visible blue glow in response to the ultraviolet in sunlight.
In some cases, fluorescent materials age and their intensity is reduced with repeated exposures; however evidence of this effect is mostly from analysis of liquids and powders (Radley and Grant 1959:60,64).
anthropology.buffalo.edu /Lithics/uvfa-ms.html   (9465 words)

  
 Fluorescence Lifetime Techniques   (Site not responding. Last check: )
The measurement of fluorescence lifetimes is a powerful tool for the study of excited states.
The applications of fluorescence lifetimes can be extended by the integration with other spectroscopic measurements, such as the emission wavelength and the time-dependence of anisotropy.
The Time-Resolved Anisotropy is determined by placing polarizers in the excitation and emission channels and measuring the fluorescence decay of the parallel and perpendicular components of the emission.
www.pti-nj.com /fluorescence_4.html   (335 words)

  
 fluorescence articles on Encyclopedia.com   (Site not responding. Last check: )
fluorescence FLUORESCENCE [fluorescence], luminescence in which light of a visible color is emitted from a substance under stimulation or excitation by light or other forms of electromagnetic radiation or by certain other means.
Phosphorescence is distinguished from fluorescence in that it continues even after the radiation causing it has ceased.
It melts at 218°C and boils at 354°C. When pure it is colorless and has a violet fluorescence; it darkens when exposed to sunlight.
www.encyclopedia.com /articles/04560.html   (469 words)

  
 SPEX & IBH Spectrofluorometers, steady-state, lifetime, remote sensing and process control
No matter what your fluorescence application, the diverse set of base instruments, accessories, and alternatives, will allow you to achieve the best fluorometer possible, a fluorometer that will do your work easily, reproducibly, and accurately.
The 295 nm LED matches the absorption maxima of the naturally fluorescent amino acids tryptophan and tyrosine.
Tryptophan fluorescence is widely used as a probe of protein structure and dynamics.
www.jobinyvon.com /usadivisions/Fluorescence   (895 words)

  
 Principles of Fluorescence Spectroscopy
Early fluorescent probes were those derived from histochemical staining of cells, a limited number of lipid and conjugatable probes, and of course, intrinsic fluorescence from proteins.
The fluorescence technology for DNA sequencing is advancing rapidly due to the goal of sequencing the human genome.
And finally, who would have expected in 1983 that the gene for the green fluorescence protein could be introduced into cells with spontaneous folding and formation of the fully fluorescent protein.
cfs.umbi.umd.edu /cfs/princ2.html   (967 words)

  
 Mineral Gallery - The Fluorescent Minerals
The fluorescent light is emitted when those electrons jump down to a lower energy state and emit a light of their own.
However if an unknown mineral does not fluoresce, it should not so quickly be dismissed as not being the suspected fluorescing mineral, unless that mineral is reported to always fluoresce.
Fluorescence is not usually an absolute property found in all specimens of even a named fluorescent mineral, but there do exist some minerals that are so reliably fluorescent that fluorescence is the best test to use.
mineral.galleries.com /minerals/property/fluoresc.htm   (747 words)

  
 Chlorophyll Fluorescence Analysis of Cyanobacterial Photosynthesis and Acclimation -- Campbell et al. 62 (3): 667 -- ...
This is a Stern-Volmer formulation that measures the ratio of quenched to remaining fluorescence.
Fluorescence spectra are from samples of equal chlorophyll content but are not otherwise normalized.
Fluorescence analysis is an integral part of studies of photosynthesis in cyanobacteria and other organisms.
mmbr.asm.org /cgi/content/full/62/3/667   (8147 words)

  
 Botany online: Microscopy - Fluorescence Microscopy
Fluorescence microscopy is based on the fact that some molecules emit part of the light absorbed by them as longer waves.
A well-known example is the red fluorescence of chlorophyll.
Since roughly twenty years fluorescence microscopy is flowering again, on one hand, because the range of fluorochromes became much broader and on the other hand, because completely new approaches like indirect fluorescence could be used successfully.
www.biologie.uni-hamburg.de /b-online/e03/03b.htm   (406 words)

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