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Topic: Photoreceptor


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Eye

In the News (Tue 10 Nov 09)

  
  U.S. Patent: 5737671 - Electrophotographic photoreceptor and an image forming method using the same - April 7, 1998
To form an image, the transparent substrate of the photoreceptor is exposed to image light, while substantially at the same time, a magnetic brush with conductive magnetic toner to which a bias voltage is applied is made to slidably contact with the surface of the photoreceptor.
An electrophotographic photoreceptor of the present invention includes a transparent substrate, and is used for an electrophotography system in which the transparent substrate of the photoreceptor is exposed to image light, and a developing process is carried out under a bias voltage applied thereto by a developing means provided on the electrophotographic photoreceptor.
In the photoreceptor of the invention using the thin film, the absolute value of the quantity of light incident on the photoconductive layer is larger than in the photoreceptor not using the thin film.
www.everypatent.com /comp/pat5737671.html   (3559 words)

  
 Electrophotographic photoreceptor for wet development - Patent 7078139
The electrophotographic photoreceptor of claim 1, wherein the electrophotographic photoreceptor further comprises an intermediate layer for preventing charge injection from the electrically conductive substrate, between the electrically conductive substrate and the photosensitive layer.
In the photosensitive layer of the electrophotographic photoreceptor for wet development according to the present invention, the amount of the charge transport material including the hole transport material and the electron transport material is preferably in the range of 10 to 40% by weight based on the total weight of the photosensitive layer.
The photoreceptor unit generally includes a drum 28 that is attachable to and detachable from the electrophotographic apparatus 30, and an electrophotographic photoreceptor 29 disposed on the drum 28.
www.freepatentsonline.com /7078139.html   (4811 words)

  
 Webvision: Photoreceptors
The rods are photoreceptors that contain the visual pigment - rhodopsin and are sensitive to blue-green light with a peak sensitivity around 500 nm wavelength of light.
Thus in terms of densities of the different photoreceptor populations in the human retina, it is clear that the cone density is highest in the foveal pit and falls rapidly outside the fovea to a fairly even density into the peripheral retina (see graph and map below) (Osterberg, 1935; Curcio et al., 1987).
The job of the photoreceptor cell in the retina is to catch quanta of light in the visual pigment-containing membranes of the outer segment and pass a message, concerning numbers of quanta of light and sensitivities to the different wavelengths, to the next stage of integration and processing at the outer plexiform layer (see Transduction).
webvision.med.utah.edu /photo2.html   (3198 words)

  
 van der Spuy, Mol Vis 2005; 11:542-553.   (Site not responding. Last check: 2007-11-03)
The cone arrestin signal was restricted to the residual photoreceptor inner segments and was not detected in the cell bodies, axons, or axon terminals of the surviving photoreceptors.
Although cone-like photoreceptors appear to develop in the LCA retina, immunolabeling for cone arrestin was not detected in the cell nuclei, axons, or synaptic terminals of the surviving photoreceptors.
This suggests that the connectivity of the surviving photoreceptors in the outer nuclear layer with the cells of the inner nuclear layer at the outer plexiform layer is abnormal, leading to a disruption of retinal organization and signal transduction.
www.molvis.org /molvis/v11/a64   (6157 words)

  
 Fluorescence behavior of Euglena photoreceptor[para] Photochemistry and Photobiology - Find Articles
The photoreceptor, a three-dimensional (3D) proteic crystal, is composed of a stack of more than 100 crystalline sheets with a regular organization of component proteins.
It acts as a photoreceptor for the step-up photophobic response (transition from dark to light), but it is not involved in the step-down photophobic response (transition from light to dark).
The photoreceptor of Euglena behaves in a similar manner, and the kinetics of its photocycle was measured digitizing fluorescence images of the organelle at a constant rate (21).
www.findarticles.com /p/articles/mi_qa3931/is_200307/ai_n9285277   (838 words)

  
 Dynamic Behavior of Rod Photoreceptor Disks -- Chen et al. 83 (3): 1403 -- Biophysical Journal
Adler, R. Preparation, enrichment, and growth of purified cultures of neurons and photoreceptors from chick embryos and from normal and mutant mice.
Diffusion coefficient of the cyclic GMP analog 8-(fluoresceinyl)thioguanosine 3',5' cyclic monophosphate in the salamander rod outer segment.
Transport of phosphatidylcholine to Xenopus photoreceptor rod outer segments in the presence of tunicamycin.
www.biophysj.org /cgi/content/full/83/3/1403   (6250 words)

  
 THE cGMP-GATED CHANNEL OF PHOTORECEPTOR CELLS:
The molecular properties of the channel complex and the possible role of Ca2+-calmodulin modulation of the channel during photoactivation and photorecovery is discussed in relation to the current mechanism of phototransduction in photoreceptor cells.
Photoreceptor and olfactory channel subunits also contain a segment which has considerable sequence similarity to the pore region of the voltage-gated K+channel (Goulding et al.
In rod and cone photoreceptor cells the * -subunit undergoes a post-translational cleavage reaction involving the removal of a segment at the N-terminus.
www.bbsonline.org /Preprints/OldArchive/bbs.neur3.molday.html   (8629 words)

  
 Photoreceptor cell - Psychology Wiki - A Wikia wiki
Photoreceptor cells are found in the retina of the eye and are responsible for transducing, or converting, light into nerve signals that can be ultimately transmitted to the brain via the optic nerve.
In vertebrates, there are two types of photoreceptor cells called rods and cones.
The function of the photoreceptor cell is to convert the light energy into a form of energy more readily usable or functional to the organism: this conversion is called signal transduction.
psychology.wikia.com /wiki/Photoreceptor_cell   (478 words)

  
 Electrophotographic photoreceptor and image forming device - Patent 6858368
The degradation in the photoreceptor is thought to be primarily due to an increase in the number of molecules of the charge generating agent that have lost their ability to function as photoconductors after repeatedly generating and discharging an electric charge when optically illuminated.
An electrophotographic photoreceptor according to a first aspect of the present invention is employed in an image forming device having a flash fixing means that fixes a toner image to a recording medium by generating a flash light and exposing the toner image thereto.
An electrophotographic photoreceptor according to another aspect of the present invention is employed in an image forming device having a flash fixing means that fixes a toner image to a recording medium by generating a flash light and exposing the toner image thereto.
www.freepatentsonline.com /6858368.html   (10684 words)

  
 Photoreceptor - Wikipedia, the free encyclopedia
A photoreceptor, or photoreceptor cell, is a specialized type of neuron found in the eye's retina that is capable of phototransduction.
All photoreceptors in humans are found in the outer nuclear layer in the retina at the back of each eye, while the bipolar and ganglion cells that transmit information from photoreceptors to the brain are in front of them.
Since the photoreceptor is depolarized in the dark, a high amount of glutamate is being released to bipolar cells in the dark.
en.wikipedia.org /wiki/Photoreceptor   (1849 words)

  
 BioMed Central | Full text | Machine learning approaches to supporting the identification of photoreceptor-enriched ...
Photoreceptor degeneration, for example, constitutes an important cause of visual impairment affecting all age groups and ethnic backgrounds [1].
Development and maintenance of photoreceptor function in the retina requires appropriate regulation of gene expression, especially for genes specifically or highly expressed in photoreceptor cells during retinal development (photoreceptor-enriched genes).
It has been shown that these genes are involved in maintaining the integrity of photoreceptor outer segment and are therefore critical for rod photoreceptor viability and regulation of disk morphogenesis [11].
www.biomedcentral.com /1471-2105/7/116   (6293 words)

  
 Photoreceptor Differentiation during Retinal Development, Growth, and Regeneration in a Metamorphic Vertebrate -- Mader ...   (Site not responding. Last check: 2007-11-03)
Photoreceptors and opsins in premetamorphic and postmetamorphic retina
Kelley MW, Turner JK, Reh TA (1995) Ligands of steroid/thyroid receptors induce cone photoreceptors in vertebrate retina.
Raymond PA (1985) Cytodifferentiation of photoreceptors in larval goldfish: delayed maturation of rods.
www.jneurosci.org /cgi/content/full/24/50/11463   (5893 words)

  
 01-080 (New Photoreceptor)
A photoreceptor is a cell in the eye that contains a chemical called a photopigment that changes its properties in response to light.
The delay between the onset of stimulus and the beginning of the response is extraordinarily long compared with conventional photoreceptors (rods and cones).
This is presumably because the newly discovered photoreceptors are specialized to detect slow changes in environmental lighting, not the rapid events that are so important in pattern vision.
www.brown.edu /Administration/News_Bureau/2001-02/01-080.html   (929 words)

  
 Oxidative Stress-induced Apoptosis in Retinal Photoreceptor Cells Is Mediated by Calpains and Caspases and Blocked by ...   (Site not responding. Last check: 2007-11-03)
Oxidative Stress-induced Apoptosis in Retinal Photoreceptor Cells Is Mediated by Calpains and Caspases and Blocked by the Oxygen Radical Scavenger CR-6 -- Sanvicens et al.
in photoreceptor apoptosis induced by the nitric oxide donor
The percentage of cells that showed increased Ca levels in 661W photoreceptor cells induced by SNP treatment is indicated in each panel.
www.jbc.org /cgi/content/full/279/38/39268   (6772 words)

  
 Coexpression of Two Visual Pigments in a Photoreceptor Causes an Abnormally Broad Spectral Sensitivity in the Eye of ...   (Site not responding. Last check: 2007-11-03)
R1–R4 are distal photoreceptors, which form the distal two-thirds of the rhabdom; R5–R8 are proximal photoreceptors, forming the proximal one-third of the rhabdom; and R9 is a basal cell.
In type II, a fluorescing pigment, 3-hydroxyretinol, is concentrated in the distal portion of the photoreceptor layer (indicated by blue).
The sensitivity spectrum of R9 photoreceptors is an open question; it probably peaks in the orange wavelength range, but electrophysiological data are lacking so far.
www.jneurosci.org /cgi/content/full/23/11/4527   (4242 words)

  
 TOPOGRAPHY OF THE PHOTORECEPTOR CELL OF VISION
The active elements of the photoreceptor cell, the Activas, are located within the individual dendritic structures of the cell and just inside the cell body near the colax (also known as the ciliary collar in morphology).
Following extrusion, the disk stack forming the main structure of the Outer Segment leaves the photoreceptor cell environs and is immersed in the Inter-Photoreceptor cell Matrix (IPM) until is arrives at the phagocytosis cup of the RPE.
The disk stack is not surrounded by a cell membrane while it is in the IPM although it is coated with a variety of nutrients supplied from the RPE layer.
www.4colorvision.com /files/pc-topography.htm   (432 words)

  
 The Corbo Lab > Projects   (Site not responding. Last check: 2007-11-03)
Lastly, we hope to use this network model as a blueprint for the directed differentiation of stem cells into functional photoreceptors to be used in replacement therapy for patients with retinal diseases.
Mutations in a variety of photoreceptor genes result in an strikingly abnormal morphology of the outer nuclear layer in which this usually flat cell layer is thrown into odd wavy contortions and rosettes (as seen in the figure on the right).
As part of this plan we intend to develop a system in which the cell fate of a developing photoreceptor can be switched between that of a rod and a cone simply by addition of an exogenous small molecule ligand.
pathbox.wustl.edu /~corbolab/projects.htm   (982 words)

  
 DNA Damage and Repair in Light-Induced Photoreceptor Degeneration -- Gordon et al. 43 (11): 3511 -- Investigative ...   (Site not responding. Last check: 2007-11-03)
This time course illustrates the fate of TUNEL-positive photoreceptor nuclei as fragmented DNA is first labeled, then blebbed from photoreceptors to become phagocytized by cells within the debris zone (DZ).
The number of photoreceptor cell nuclei per stack (thickness) is plotted every 150 µm on a section along a meridian from the superior edge, through or adjacent to the optic nerve, to the inferior retinal margin for each curve.
Profiles of the number of photoreceptor nuclei across the retina along a meridian from the superior edge, through the optic nerve, to the inferior edge.
www.iovs.org /cgi/content/full/43/11/3511   (7605 words)

  
 Essential role of Ca2+-binding protein 4, a Cav1.4 channel regulator, in photoreceptor synaptic function - Nature ...
The CaBP4 antisense RNA probe hybridized to the mouse photoreceptor inner segments (Fig.
Photoreceptor synaptic terminals were visualized using antibody to PSD95 (anti-PSD95; ref. 18; Fig.
Light and electron microscopy showed dramatic changes in photoreceptor synapses, including a thinner outer plexiform layer, a reduction in the number of synaptic ribbons and photoreceptor terminals and deflation of rod spherules and cone pedicles.
www.nature.com /uidfinder/10.1038/nn1320   (5605 words)

  
 Lipofuscin accumulation, abnormal electrophysiology, and photoreceptor degeneration in mutant ELOVL4 transgenic mice: A ...   (Site not responding. Last check: 2007-11-03)
by photoreceptor degeneration and atrophy of the retinal pigment
Photoreceptor cell nuclei were counted from the regions that are 200–300 µm dorsal and ventral from the optic nerve head.
Autofluorescence of the photoreceptor outer segments is evident in the control retina.
www.pnas.org /cgi/content/full/102/11/4164   (4299 words)

  
 A Fresh Look at Photoreceptor Belts:   (Site not responding. Last check: 2007-11-03)
Most readers of Recharger Magazine are aware of the existence of photoreceptor belts but have not adopted this technology in the products they offer.
The objective of this article is to explore the basic technology and future trends of belt-type photoreceptors as well as the inherent differences between a belt and a drum.
Although printers using a photoreceptor belt are not widely popular, they represent an excellent avenue for diversification of a remanufacturer's product line and can boost company profitability.
www.rechargermag.com /article.asp?id=199711065   (260 words)

  
 Mutation of the photoreceptor specific homeodomain gene Pph13 results in defects in phototransduction and rhabdomere ...   (Site not responding. Last check: 2007-11-03)
Mutation of the photoreceptor specific homeodomain gene Pph13 results in defects in phototransduction and rhabdomere morphogenesis -- Zelhof et al.
Pph13 expression is detected in all eight photoreceptor cells.
Arr1 expression is only detected in the inner photoreceptor cells (R7, R8, arrow) and rhodopsin (Rh1) is detected only in the six outer photoreceptor cells (R1-R6).
dev.biologists.org /cgi/content/full/130/18/4383   (5631 words)

  
 ScienceDaily: UT Southwestern Researchers Identify Key Photoreceptor In Fungi
Light regulates several physiological processes in fungi, including their ability to produce spores and the synchronization of their internal biological clocks, but their photoreceptors receptors that are sensitive to light and are essential for most ongoing processes were not known until this breakthrough discovery made by UT Southwestern researchers.
In this week's on-line version of Science, the researchers report that the protein White Collar 1, or WC-1, is the photoreceptor for light responses in fungi, which encompass yeast and mold.
Liu and his collaborators demonstrated that WC-1, like all known photoreceptors, is associated with a photo pigment, the molecule that is sensitive to light.
www.sciencedaily.com /releases/2002/07/020705090349.htm   (1865 words)

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