Lasers: An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.Lasers, Solid-State: Lasers which use a solid, as opposed to a liquid or gas, as the lasing medium. Common materials used are crystals, such as YAG (YTTRIUM aluminum garnet); alexandrite; and CORUNDUM, doped with a rare earth element such as a NEODYMIUM; ERBIUM; or HOLMIUM. The output is sometimes additionally modified by addition of non-linear optical materials such as potassium titanyl phosphate crystal, which for example is used with neodymium YAG lasers to convert the output light to the visible range.Laser Coagulation: The use of green light-producing LASERS to stop bleeding. The green light is selectively absorbed by HEMOGLOBIN, thus triggering BLOOD COAGULATION.Laser Therapy, Low-Level: Treatment using irradiation with LASER light of low power intensity so that the effects are not due to heat, as they are in LASER THERAPY.Lasers, Excimer: Gas lasers with excited dimers (i.e., excimers) as the active medium. The most commonly used are rare gas monohalides (e.g., argon fluoride, xenon chloride). Their principal emission wavelengths are in the ultraviolet range and depend on the monohalide used (e.g., 193 nm for ArF, 308 nm for Xe Cl). These lasers are operated in pulsed and Q-switched modes and used in photoablative decomposition involving actual removal of tissue. (UMDNS, 2005)Lasers, Dye: Tunable liquid lasers with organic compounds (i.e., dye) which have a strong absorption band, used as the active medium. During emission, the dye has to be optically excited by another light source (e.g., another laser or flash lamp). The range of the emission wavelength may be anywhere from the ultraviolet to the near infrared (i.e., from 180 to 1100nm). These lasers are operated in continuous wave and pulsed modes. (UMDNS, 2005)Laser Scanning Cytometry: A scanning microscope-based, cytofluorimetry technique for making fluorescence measurements and topographic analysis on individual cells. Lasers are used to excite fluorochromes in labeled cellular specimens. Fluorescence is detected in multiple discrete wavelengths and the locational data is processed to quantitatively assess APOPTOSIS; PLOIDIES; cell proliferation; GENE EXPRESSION; PROTEIN TRANSPORT; and other cellular processes.Keratomileusis, Laser In Situ: A surgical procedure to correct MYOPIA by CORNEAL STROMA subtraction. It involves the use of a microkeratome to make a lamellar dissection of the CORNEA creating a flap with intact CORNEAL EPITHELIUM. After the flap is lifted, the underlying midstroma is reshaped with an EXCIMER LASER and the flap is returned to its original position.Angioplasty, Laser: A technique utilizing a laser coupled to a catheter which is used in the dilatation of occluded blood vessels. This includes laser thermal angioplasty where the laser energy heats up a metal tip, and direct laser angioplasty where the laser energy directly ablates the occlusion. One form of the latter approach uses an EXCIMER LASER which creates microscopically precise cuts without thermal injury. When laser angioplasty is performed in combination with balloon angioplasty it is called laser-assisted balloon angioplasty (ANGIOPLASTY, BALLOON, LASER-ASSISTED).Laser Capture Microdissection: Techniques using a laser to cut away and harvest a specific cell or cluster of cells from a tissue section while viewing it under the microscope.Microscopy, Confocal: A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.Microdissection: The performance of dissections with the aid of a microscope.Laser-Doppler Flowmetry: A method of non-invasive, continuous measurement of MICROCIRCULATION. The technique is based on the values of the DOPPLER EFFECT of low-power laser light scattered randomly by static structures and moving tissue particulates.Corneal Surgery, Laser: Surgical techniques on the CORNEA employing LASERS, especially for reshaping the CORNEA to correct REFRACTIVE ERRORS.Light Coagulation: The coagulation of tissue by an intense beam of light, including laser (LASER COAGULATION). In the eye it is used in the treatment of retinal detachments, retinal holes, aneurysms, hemorrhages, and malignant and benign neoplasms. (Dictionary of Visual Science, 3d ed)Ophthalmoscopy: Examination of the interior of the eye with an ophthalmoscope.Infrared Rays: That portion of the electromagnetic spectrum usually sensed as heat. Infrared wavelengths are longer than those of visible light, extending into the microwave frequencies. They are used therapeutically as heat, and also to warm food in restaurants.Photorefractive Keratectomy: A type of refractive surgery of the CORNEA to correct MYOPIA and ASTIGMATISM. An EXCIMER LASER is used directly on the surface of the EYE to remove some of the CORNEAL EPITHELIUM thus reshaping the anterior curvature of the cornea.Argon: Argon. A noble gas with the atomic symbol Ar, atomic number 18, and atomic weight 39.948. It is used in fluorescent tubes and wherever an inert atmosphere is desired and nitrogen cannot be used.Ophthalmoscopes: Devices for examining the interior of the eye, permitting the clear visualization of the structures of the eye at any depth. (UMDNS, 1999)Neon: Neon. A noble gas with the atomic symbol Ne, atomic number 10, and atomic weight 20.18. It is found in the earth's crust and atmosphere as an inert, odorless gas and is used in vacuum tubes and incandescent lamps.Equipment Design: Methods of creating machines and devices.Fluorescein Angiography: Visualization of a vascular system after intravenous injection of a fluorescein solution. The images may be photographed or televised. It is used especially in studying the retinal and uveal vasculature.Erbium: Erbium. An element of the rare earth family of metals. It has the atomic symbol Er, atomic number 68, and atomic weight 167.26.Fiber Optic Technology: The technology of transmitting light over long distances through strands of glass or other transparent material.Optical Fibers: Thin strands of transparent material, usually glass, that are used for transmitting light waves over long distances.Visual Acuity: Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.Fetoscopy: Endoscopic examination, therapy or surgery of the fetus and amniotic cavity through abdominal or uterine entry.Dental Soldering: The joining of pieces of metal through the use of an alloy which has a lower melting point, usually at least 100 degrees Celsius below the fusion temperature of the parts being soldered. In dentistry, soldering is used for joining components of a dental appliance, as in assembling a bridge, joining metals to orthodontic bands, or adding to the bulk of certain structures, such as the establishment of proper contact areas on inlays and crowns with adjacent teeth. (Illustrated Dictionary of Dentistry, 1982)Angioplasty, Balloon, Laser-Assisted: Techniques using laser energy in combination with a balloon catheter to perform angioplasty. These procedures can take several forms including: 1, laser fiber delivering the energy while the inflated balloon centers the fiber and occludes the blood flow; 2, balloon angioplasty immediately following laser angioplasty; or 3, laser energy transmitted through angioplasty balloons that contain an internal fiber.Fundus Oculi: The concave interior of the eye, consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels, seen by means of the ophthalmoscope. (Cline et al., Dictionary of Visual Science, 4th ed)Optics and Photonics: A specialized field of physics and engineering involved in studying the behavior and properties of light and the technology of analyzing, generating, transmitting, and manipulating ELECTROMAGNETIC RADIATION in the visible, infrared, and ultraviolet range.Interferometry: Measurement of distances or movements by means of the phenomena caused by the interference of two rays of light (optical interferometry) or of sound (acoustic interferometry).Cornea: The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)Choroid: The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.Equipment Failure Analysis: The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.Myopia: A refractive error in which rays of light entering the EYE parallel to the optic axis are brought to a focus in front of the RETINA when accommodation (ACCOMMODATION, OCULAR) is relaxed. This results from an overly curved CORNEA or from the eyeball being too long from front to back. It is also called nearsightedness.Photolysis: Chemical bond cleavage reactions resulting from absorption of radiant energy.Iris: The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium.Photochemotherapy: Therapy using oral or topical photosensitizing agents with subsequent exposure to light.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Macular Edema: Fluid accumulation in the outer layer of the MACULA LUTEA that results from intraocular or systemic insults. It may develop in a diffuse pattern where the macula appears thickened or it may acquire the characteristic petaloid appearance referred to as cystoid macular edema. Although macular edema may be associated with various underlying conditions, it is most commonly seen following intraocular surgery, venous occlusive disease, DIABETIC RETINOPATHY, and posterior segment inflammatory disease. (From Survey of Ophthalmology 2004; 49(5) 470-90)Intraocular Pressure: The pressure of the fluids in the eye.Retina: The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.Diabetic Retinopathy: Disease of the RETINA as a complication of DIABETES MELLITUS. It is characterized by the progressive microvascular complications, such as ANEURYSM, interretinal EDEMA, and intraocular PATHOLOGIC NEOVASCULARIZATION.Dermatologic Surgical Procedures: Operative procedures performed on the SKIN.Fluorescent Dyes: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.Glaucoma: An ocular disease, occurring in many forms, having as its primary characteristics an unstable or a sustained increase in the intraocular pressure which the eye cannot withstand without damage to its structure or impairment of its function. The consequences of the increased pressure may be manifested in a variety of symptoms, depending upon type and severity, such as excavation of the optic disk, hardness of the eyeball, corneal anesthesia, reduced visual acuity, seeing of colored halos around lights, disturbed dark adaptation, visual field defects, and headaches. (Dictionary of Visual Science, 4th ed)Microscopy, Fluorescence, Multiphoton: Fluorescence microscopy utilizing multiple low-energy photons to produce the excitation event of the fluorophore. Multiphoton microscopes have a simplified optical path in the emission side due to the lack of an emission pinhole, which is necessary with normal confocal microscopes. Ultimately this allows spatial isolation of the excitation event, enabling deeper imaging into optically thick tissue, while restricting photobleaching and phototoxicity to the area being imaged.Corneal Stroma: The lamellated connective tissue constituting the thickest layer of the cornea between the Bowman and Descemet membranes.Photons: Discrete concentrations of energy, apparently massless elementary particles, that move at the speed of light. They are the unit or quantum of electromagnetic radiation. Photons are emitted when electrons move from one energy state to another. (From Hawley's Condensed Chemical Dictionary, 11th ed)Microsurgery: The performance of surgical procedures with the aid of a microscope.Microscopy, Electron, Scanning: Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.Tomography, Optical Coherence: An imaging method using LASERS that is used for mapping subsurface structure. When a reflective site in the sample is at the same optical path length (coherence) as the reference mirror, the detector observes interference fringes.Photosensitizing Agents: Drugs that are pharmacologically inactive but when exposed to ultraviolet radiation or sunlight are converted to their active metabolite to produce a beneficial reaction affecting the diseased tissue. These compounds can be administered topically or systemically and have been used therapeutically to treat psoriasis and various types of neoplasms.Yttrium: An element of the rare earth family of metals. It has the atomic symbol Y, atomic number 39, and atomic weight 88.91. In conjunction with other rare earths, yttrium is used as a phosphor in television receivers and is a component of the yttrium-aluminum garnet (YAG) lasers.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Iridectomy: Surgical removal of a section of the iris.Retinal DiseasesScattering, Radiation: The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Hair Removal: Methods used to remove unwanted facial and body hair.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Surgical Flaps: Tongues of skin and subcutaneous tissue, sometimes including muscle, cut away from the underlying parts but often still attached at one end. They retain their own microvasculature which is also transferred to the new site. They are often used in plastic surgery for filling a defect in a neighboring region.Diagnostic Techniques, Ophthalmological: Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.Choroidal Neovascularization: A pathological process consisting of the formation of new blood vessels in the CHOROID.Regional Blood Flow: The flow of BLOOD through or around an organ or region of the body.Micromanipulation: The performance of dissections, injections, surgery, etc., by the use of micromanipulators (attachments to a microscope) that manipulate tiny instruments.Optical Devices: Products or parts of products used to detect, manipulate, or analyze light, such as LENSES, refractors, mirrors, filters, prisms, and OPTICAL FIBERS.Retinal Vessels: The blood vessels which supply and drain the RETINA.Dissection: The separation and isolation of tissues for surgical purposes, or for the analysis or study of their structures.Varicose Veins: Enlarged and tortuous VEINS.Refractometry: Measurement of the index of refraction (the ratio of the velocity of light or other radiation in the first of two media to its velocity in the second as it passes from one into the other).Phototherapy: Treatment of disease by exposure to light, especially by variously concentrated light rays or specific wavelengths.Spectrum Analysis, Raman: Analysis of the intensity of Raman scattering of monochromatic light as a function of frequency of the scattered light.Birefringence: The property of nonisotropic media, such as crystals, whereby a single incident beam of light traverses the medium as two beams, each plane-polarized, the planes being at right angles to each other. (Cline et al., Dictionary of Visual Science, 4th ed)Optical Tweezers: A technique that uses LASERS to trap, image, and manipulate small objects (biomolecules, supramolecular assembles, DENDRIMERS) in three dimensional space. (From Glossary of Biotechnology and Nanobiotechnology Terms, 4th ed.)Optic Disk: The portion of the optic nerve seen in the fundus with the ophthalmoscope. It is formed by the meeting of all the retinal ganglion cell axons as they enter the optic nerve.Krypton: A noble gas that is found in the atmosphere. It has the atomic symbol Kr, atomic number 36, atomic weight 83.80, and has been used in electric bulbs.Wound Healing: Restoration of integrity to traumatized tissue.Nerve Fibers: Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.

Fluorimetric multiparameter cell assay at the single cell level fabricated by optical tweezers. (1/3679)

A fluorimetric multi-parameter cell sensor at the single cell level is presented which makes it possible to observe the physiological behavior of different cell lines, different physiological parameters, and statistical data at the same time. Different cell types were immobilized at predefined positions with high accuracy using optical tweezers and adhesion promoting surface layers. The process is applicable to both adherent and non-adherent cells. Coating of the immobilization area with mussel adhesive protein was shown to be essential for the process. Intracellular proton and calcium concentrations in different cell classes were simultaneously imaged and the specific activation of T lymphocytes was demonstrated. This method should be especially useful for drug screening due to the small sample volume and high information density.  (+info)

A repetitive mode of activation of discrete Ca2+ release events (Ca2+ sparks) in frog skeletal muscle fibres. (2/3679)

1. Ca2+ release events (Ca2+ 'sparks'), which are believed to arise from the opening of a sarcoplasmic reticulum (SR) Ca2+ release channel or a small cluster of such channels that act as a release unit, have been measured in single, frog (Rana pipiens) skeletal muscle fibres. 2. Under conditions of extremely low rates of occurrence of Ca2+ sparks we observed, within individual identified triads, repetitive Ca2+ release events which occurred at a frequency more than 100-fold greater than the prevailing average event rate. Repetitive sparks were recorded during voltage-clamp test depolarizations after a brief (0.3-2 s) repriming interval in fibres held at 0 mV and in chronically depolarized, 'notched' fibres. 3. These repetitive events are likely to arise from the re-opening of the same SR Ca2+ release channel or release unit operating in a repetitive gating mode ('rep-mode'), rather than from the random activation of multiple, independent channels or release units within a triad. A train of rep-mode events thus represents a series of Ca2+ sparks arising from a single location within the fibre. Rep-mode events are activated among different triads in a random manner after brief repriming. The frequency of repetitive events among all identified events during voltage-clamp depolarization to 0 mV after brief repriming was 3.9 +/- 1.3 %. The occurrence of repetitive events was not related to exposure of the fibre to laser illumination. 4. The events observed within a rep-mode train exhibited a relatively uniform amplitude. Analysis of intervals between identified events in triads exhibiting rep-mode trains indicated similar variations of fluorescence as in neighbouring, quiescent triads, suggesting there was not a significant number of small, unidentified events at the triads exhibiting rep-mode activity. 5. The distribution of rep-mode interspark intervals exhibited a paucity of events at short intervals, consistent with the need for recovery from inactivation before activation of the next event in a repetitive train. The mean interspark interval of repetitive sparks during voltage-clamp depolarizations was 88 +/- 5 ms, and was independent of membrane potential. 6. The individual Ca2+ sparks within a rep-mode train were similar in average amplitude and spatiotemporal extent to singly occurring sparks, suggesting a common mechanism for termination of the channel opening(s) underlying both types of events. The average properties of the sparks did not vary during a train. The relative amplitude of a spark within a rep-mode was not correlated with its rise time. 7. Repetitive Ca2+ release events represent a mode of gating of SR Ca2+ release channels which may be significant during long depolarizations and which may be influenced by the biochemical state of the SR ryanodine receptor Ca2+ release channels.  (+info)

Elimination of EVE protein by CALI in the short germ band insect Tribolium suggests a conserved pair-rule function for even skipped. (3/3679)

The question of the degree of evolutionary conservation of the pair-rule patterning mechanism known from Drosophila is still contentious. We have employed chromophore-assisted laser inactivation (CALI) to inactivate the function of the pair-rule gene even skipped (eve) in the short germ embryo of the flour beetle Tribolium. We show that it is possible to generate pair-rule type phenocopies with defects in alternating segments. Interestingly, we find the defects in odd numbered segments and not in even numbered ones as in Drosophila. However, this apparent discrepancy can be explained if one takes into account that the primary action of eve is at the level of parasegments and that different cuticular markers are used for defining the segment borders in the two species. In this light, we find that eve appears to be required for the formation of the anterior borders of the same odd numbered parasegments in both species. We conclude that the primary function of eve as a pair rule gene is conserved between the two species.  (+info)

Enhanced hatching rate of bovine IVM/IVF/IVC blastocysts using a 1.48-micron diode laser beam. (4/3679)

PURPOSE: Our purpose was to test whether zona pellucida (ZP) drilling using a 1.48-micron diode laser beam on bovine IVM/IVF/IVC blastocysts is effective for embryo hatching. METHODS: Blastocysts produced in vitro at day 7 after IVF were divided into control and laser-drilled groups, respectively. RESULTS: When the rates of in vitro development of bovine embryos were examined, the average cleavage rate (> or = two-cell) was 82.3% and the blastocyst rate at day 7 after IVF was 32.5%. Using these blastocysts, when the laser drilling effect was investigated at 48 hr after treatment, the total hatching rate in the laser-drilled group (98.0%) was significantly higher than that in the control group (60.0%) (P < 0.001). Especially, the hatched rate of the laser-drilled group (68.0%) was significantly enhanced compared with that of the control group (30.0%) (P < 0.001). CONCLUSIONS: These results demonstrated that laser ZP drilling on bovine IVM/IVF/IVC blastocysts can significantly increase the hatching rate.  (+info)

Altered ligand rebinding kinetics due to distal-side effects in hemoglobin chico (Lysbeta66(E10) --> thr). (5/3679)

Hb Chico is an unusual human hemoglobin variant that has lowered oxygen affinity, but unaltered cooperativity and anion sensitivity. Previous studies showed these features to be associated with distal-side heme pocket alterations that confer increased structural rigidity on the molecule and that increase water content in the beta-chain heme pocket. We report here that the extent of nanosecond geminate rebinding of oxygen to the variant and its isolated beta-chains is appreciably decreased. Structural alterations in this variant decrease its oxygen recombination rates without significantly altering rates of migration out of the heme pocket. Data analysis indicates that one or more barriers that impede rebinding of oxygen from docking sites in the heme pocket are increased, with less consequence for CO rebinding. Resonance Raman spectra show no significant alterations in spectral regions sensitive to interactions between the heme iron and the proximal histidine residue, confirming that the functional differences in the variant are due to distal-side heme pocket alterations. These effects are discussed in the context of a schematic representation of heme pocket wells and barriers that could aid the design of novel hemoglobins with altered ligand affinity without loss of the normal allosteric responses that facilitate unloading of oxygen to respiring tissues.  (+info)

Laser induced phagocytosis in the pigment epithelium of the Hunter dystrophic rat. (6/3679)

The retinae of 14-day-old Hunter dystrophic rats have been subjected to low-energy irradiation by a pulsed ruby laser. Fifteen days after exposure, pigment epithelial cells had proliferated and repopulated the irradiated areas. In all such areas the subretinal photoreceptor debris had been reduced or lost.  (+info)

Undercarboxylation of recombinant prothrombin revealed by analysis of gamma-carboxyglutamic acid using capillary electrophoresis and laser-induced fluorescence. (7/3679)

The gamma-carboxyglutamic acid (Gla) content of several variants of human prothrombin has been measured by using capillary electrophoresis and laser-induced fluorescence (CE-LIF). Both plasma-derived prothrombin and recombinant prothrombin contain ten residues of Gla per molecule of protein. In contrast, a variant of human prothrombin (containing the second kringle domain of bovine prothrombin) was separated into two populations that differed in their Gla content. Direct measurement of the Gla content showed an association with the presence or absence of the calcium-dependent conformational change that is required for prothombinase function. Thus, the CE-LIF assay is useful in determining the carboxylation status of recombinant proteins.  (+info)

High-speed, random-access fluorescence microscopy: II. Fast quantitative measurements with voltage-sensitive dyes. (8/3679)

An improved method for making fast quantitative determinations of membrane potential with voltage-sensitive dyes is presented. This method incorporates a high-speed, random-access, laser-scanning scheme (Bullen et al., 1997. Biophys. J. 73:477-491) with simultaneous detection at two emission wavelengths. The basis of this ratiometric approach is the voltage-dependent shift in the emission spectrum of the voltage-sensitive dye di-8-butyl-amino-naphthyl-ethylene-pyridinium-propyl-sulfonate (di-8-ANEPPS). Optical measurements are made at two emission wavelengths, using secondary dichroic beamsplitting and dual photodetectors (<570 nm and >570 nm). Calibration of the ratiometric measurements between signals at these wavelengths was achieved using simultaneous optical and patch-clamp measurements from adjacent points. Data demonstrating the linearity, precision, and accuracy of this technique are presented. Records obtained with this method exhibited a voltage resolution of approximately 5 mV, without any need for temporal or spatial averaging. Ratiometric recordings of action potentials from isolated hippocampal neurons are used to illustrate the usefulness of this approach. This method is unique in that it is the first to allow quantitative determination of dynamic membrane potential changes in a manner optimized for both high spatiotemporal resolution (2 micrometers and <0.5 ms) and voltage discrimination.  (+info)

  • All lasers were power-matched to 50 mW and beam profile-size matched. (
  • A library for pulse lasers is also being developed for the generic integration platform. (
  • The Mobius source was a customized G1R2 laser that was used to produce a comb spectrum of user-selectable visible wavelengths with approximately one nanosecond pulse duration and a 20 MHz repetition rate. (
  • Lasers serve many conventional applications today, but with enough power, they could be used as weaponry. (
  • We are developing a semiconductor optical chip with a laser source that can achieve the tuning requirements for rapid spectral scanning and plan to integrate further OCT apparatus for full system-on-chip solutions. (
  • As it turned out, some details of my claims, most notably my invoking Star Trek as a violator of laser physics, prompted a healthy discussion. (
  • As a fictional technology, the foundations of phasers in physics are a bit shaky, but in concept, phasers would share some physical attributes with lasers. (
  • MOUNTAIN VIEW, Calif., Oct. 27, 2011 - Mobius Photonics, an innovative producer of short pulsed fiber laser sources (IR, green, and UV laser), announces that its "G1R2" laser source has been used in super-resolution microscopy experiments at the Max Planck Institute for Biophysical Chemistry (Göttingen, Germany). (
  • Founded in 2005, Mobius Photonics, Inc. produces fiber-based laser sources for applications ranging from material processing for solar cell manufacturing, semiconductor fabrication and assembly, and flat panel display manufacturing, to scientific uses such as super-resolution microscopy. (
  • The experiments demonstrated that a laser-based fluorescence microscopy technique called stimulated emission depletion (STED) microscopy could be used to image intact, living, multicellular organisms. (
  • A word of caution, however if you are using a 561 nm laser to excite PE, the traditional 575/26 and 585/42 nm bandpass filters traditionally used for PE detection are too close to the 561 nm emission, and are not adequately blocked for this laser line. (
  • In our original Cytometry paper, we used a 610/20 nm bandpass to avoid the laser line this has proven to be a less-than-optimal choice, as it is too far shifted off the PE emission spectrum. (
  • We develop a scheme in which we use a laser operating at a discrete set of equally spaced wavelengths that can be matched to the internationally standardized telecommunication wavelengths (ITU-grid). (
  • A photon is a particle (which lasers also emit) with mass, although it is extremely small, and a maser emits microwaves instead of light, although in practice it can emit wavelengths other than microwaves as well. (
  • Our G1R2 laser allowed researchers to test and select optimum wavelengths for imaging samples expressing GFP. (
  • I ve also talked with several LSR II users who think they see high backgrounds in their FITC channel when exciting PE with a 532 nm laser, and the cause is definitely a FITC filter that insufficiently excludes green laser light. (
  • We ve since had several 590/20 nm filter made by Chroma and Semrock, and these are much more sensitive for PE while being compatible with 561 nm laser light. (
  • On a fundamental level, lasers are simply amplified light, but they exhibit some special properties that distinguish them from, say, the cold glow of the fluorescent tube over your head or the IKEA lamp in the corner. (
  • Moving forward, remember one thing about lasers: they're made of light. (
  • In the STW LWAVETECH project we focus on tunable lasers for gas detection based on an AWG laser and new interferometer lay-out structures. (
  • Hello everyone I completely agree with Mario that a 532 nm green laser can certainly be compatible with FITC detection if the correct bandpass filter is used. (
  • We ve done some comparisons between 532 and 561 nm lasers for PE detection, which are also included in the linked document. (
  • Lasers transmit energy, and just as a magnifying glass can focus the sun's rays to ignite a piece of paper or burn an insect, the energy from a high-powered laser could damage a target. (
  • Mach-Zehnder modulators integrated with these lasers could be operated up to 12.5 Gbps with output power up to 4 mW in the fiber. (
  • I m attaching data (Telford_561nm_laser.pdf) where you can see a comparison between filters ranging from 575 nm to 610 nm, using 488, 532 and 561 nm laser sources (power-matched at 50 mW). (
  • 561 nm lasers at 50 mW improve PE sensitivity somewhat when compared to 532 nm at the same power level using our new 590/20 nm filter this is not too surprising if you look at the PE excitation spectrum, which peaks around 556-560 nm. (
  • But 561 nm lasers are now available at 100 mW, and higher power units are coming, so they should be comparable in power to the green very soon. (
  • It would seem using the words "Star Trek" and "lasers" in the same sentence is a cardinal mistake, as anyone even remotely familiar with the universe will tell you they harness the power of phasers, not lasers (duh). (
  • We demonstrate an endoscopic imaging system for microscopic flow measurement (for example blood flow in tissue) using laser speckle contrast imaging. (
  • Recently, however, the U.S. Navy declared its Laser Weapon System mounted aboard the USS Ponce ready for defensive use against drones. (
  • Added Leonardo, "Building on our experience in super-resolution microscopy, Mobius has recently developed a new prototype laser that offers similar capabilities to our G1R2, but from an easier-to-use, longer life system. (
  • The result is a laser system designed to allow high-resolution image generation with fast acquisition times. (
  • Excimer lasers (the name is derived from the terms excited and dimers ) use reactive gases, such as chlorine and fluorine, mixed with inert gases such as argon, krypton or xenon. (
  • The ground-based laser-space mirror part of this effort built largely on DARPA efforts toward high-powered, gas-phase excimer lasers (that could emit in the shorter, more water-penetrating region of the electromagnetic spectrum) that had led to the demonstration of a workable, moderate power, laser-optical receiver combination. (
  • Excimer lasers would expand into medical arenas, especially for corrective eye surgery. (
  • Excimer lasers are powerful and versatile light sources in the UV range of the electromagnetic spectrum. (
  • Lasik, microkeratomes and excimer lasers are flawed to begin with but at the bare minimum need to be labelled as the high risk devices for which they are. (
  • One practical example is the small portable lasers in the shape of narrow flashlights, which are used to scan surfaces of a scene in search of fingerprints. (
  • The world's largest X-ray laser in Germany, promises to shed new light onto very small things by allowing scientists to penetrate the inner workings of atoms, viruses and chemical reactions. (
  • world's most powerful laser pulses and it fits on a tabletop. (
  • Today, just a handful of laser systems around the world with the requisite potential are the flagships of large-scale research facilities, like those in Japan and the United States - and in Germany where the world's strongest laser of its type, the European XFEL, is to be found in the Hamburg area. (
  • Scientists at the University of Cambridge say the process involves short laser pulses to erase words and images by heating the printed material to the point that it vaporizes. (
  • A linear sequence of up to 12 laser pulses can be triggered at the touch of a button on the slit lamp joystick. (
  • Our drilling processes employ ultra-short laser pulses (in the picosecond range) that remove glass through nonlinear effects. (
  • The most powerful laser system in the world developed and installed by Thales in Romania with the capacity to deliver pulses with the record power level of 10 petawatts, was formally accepted on October 11, 2019 by our Customer, the National Institute of Physics and Nuclear Engineering Horia Hulubei (IFIN-HH). (
  • The Extreme Light Infrastructure for Nuclear Physics (ELI-NP) project in Romania recently reached on March 20, 2019 a significant milestone: the ultra-high intensity laser system developed by Thales has successfully generated its first pulses at a peak power level of 10 petawatts (PW) equivalent to 1016 watts : 10.9PW, at 1 shot/min compressed in a pulse just 22.3 femtoseconds long to be precise. (
  • Ruxin Li and his colleagues hope that they can make laser pulses that could rip apart empty space. (
  • The robot shoots the leaves of the unwanted plants with short laser pulses, which causes a weakening in their vitality," reports Dr. Pastrana. (
  • The laser medium can be a solid, gas, liquid or semiconductor . (
  • Degradation of the cleaved light output surface of a semiconductor crystal injection laser is reduced through control of surface recombination by providing an annealed optically transparent coating at least one ingredient of which has a higher bandgap than said crystal over the cleaved light output surface. (
  • 1. In a semiconductor crystal laser of the type having an active lasing region in a laser crystal of semiconductor material essentially perpendicular to a cleaved light output surface, the improvement for reducing heating produced by carrier surface recombination at said cleaved surface comprising, an annealed coating of an optically transparent compound, at least one element thereof having a higher bandgap than that of said laser crystal. (
  • 2. The laser of claim 1 wherein said semiconductor is selected from the group consisting of GaAs, GaAlAs and GaInAsP. (
  • 4. In a semiconductor crystal injection laser having at least one cleaved light output surface and ohmic contacts on the surfaces perpendicular thereto, the improvement comprising an annealed optically transparent coating of a surface recombination control material, at least one ingredient of which has a bandgap greater than that of said semiconductor crystal covering said at least one cleaved surface. (
  • 5. The improvement of claim 4 wherein said semiconductor crystal of said laser is selected from a group consisting of GaAs, GaAlAs and GaInAsP and said recombination control material is a member selected from the group consisting of ZnS, CdS, CdTe and CdSe. (
  • The technical field of the invention is that of semiconductor injection lasers wherein an input current is converted to a coherent light output. (
  • Injection lasers employ a semiconductor crystal of a binary or mixed compound of elements usually from group III and group V of the periodic table. (
  • In these structures, a cleaved surface of the semiconductor crystal is employed as a partially reflecting mirror at the ends of the laser cavity. (
  • Helium-neon and semiconductor lasers have become standard parts of the field surveyor's equipment. (
  • We are developing a semiconductor optical chip with a laser source that can achieve the tuning requirements for rapid spectral scanning and plan to integrate further OCT apparatus for full system-on-chip solutions. (
  • Relaxation oscillation dynamics in semiconductor diode lasers with optical feedback. (
  • Digitally tunable dual wavelength emission from semiconductor ring lasers with filtered optical feedback. (
  • Semiconductor ring laser with on-chip filtered optical feedback for discrete wavelength tuning. (
  • The main use for both lasers being the investigation into inertial confinement fusion, high energy density physics and nuclear weapons research. (
  • One of my best friends is an Army helicopter pilot, and a couple of his fellow pilots had their vision seriously damaged by someone (they allege bored Russian troops) shining high-powered lasers into their choppers as they flew patrols in Bosnia. (
  • I love lasers, I've been mucking about with them since Helium Neon tubes and solid state drive transformers became actually affordable. (
  • You learn the fundamental principles of lasers and their application in chemistry, chemical physics and biophysics. (
  • Another useful application of lasers in forensic science is spectroscopy. (
  • Chemical and Biochemical Applications of Lasers aims to give a general introduction to as well as an evaluation of the successful application of lasers in various areas, especially in the fields of chemistry and biochemistry. (
  • The HighLight Series of high power direct-diode systems and fiber lasers are simple and easy to use with a proven track record in industrial and materials processing applications. (
  • With some of the most powerful lasers in the world the conditions found in the core of the Sun can be recreated in laboratories on Earth. (
  • Graduate students, why not fix up that large frame Argon-ion laser sitting the back of the lab? (
  • The ParFocus™ zoom system delivers a homogeneous, sharply defined and reproducible laser spot on the retina and minimizes heat-related side effects on the patient's cornea. (
  • The doctor will aim the laser at the area of the retina needing treatment. (
  • For these reasons, silicon is an ideal Raman medium at the mid-wave infrared for applications in fiber Raman lasers that are being developed to replace Erbium:YAG lasers, in lasers used for skin resurfacing, and in dentistry, to whiten teeth and to eliminate the need for mechanical tooth drilling. (
  • Posted by michael on Thursday March 15, 2001 @07:58AM from the lasers-do-it-hotter dept. (
  • laser technologies are being developed for a variety of applications. (
  • This conference is part of a continuing series dedicated to recent developments and applications of x-ray lasers and other coherent x-ray sources with attention to supporting technologies and instrumentation. (
  • Medical lasers have been used for dermatology applications such as removal of port wine stains, dark spots, tattoos, acne scars and other blemishes for over a decade. (
  • Applications for and research on lasers in dentistry continues to expand since their introduction to the dental profession. (
  • Given the many factors that are appropriate to evaluate when using lasers in biological systems, the Council feels that the 510(k) process alone is not inherently sufficient to scientifically demonstrate safety, efficacy, or effectiveness for marketed dental laser applications in all cases. (
  • The CLT 500X is a laser processing workstation designed for high-precision applications in the glass, precision engineering, and electronics industries. (
  • Thales proposes a wide range of lasers solutions for the most demanding applications. (
  • Lasers today are being used in an ever-increasing number of applications. (
  • We provide innovative laser weapon systems with 360 degree coverage for sea, land and air applications. (
  • One of the desired applications of this laser would be 'breaking the vacuum' which is where the laser would have enough energy to create electrons and positrons (antimatter equivalent of the electron) from empty space. (
  • Silicon lasers are coming, and there will be many exciting applications beyond what is now being pursued, said Bahram Jalali, a University of California-Los Angeles electrical engineering professor, at an optoelectronics plenary session at Photonics West 2006. (
  • The lasers also have potential applications in biochemical sensing in the defense industry, he said. (
  • Monolithic optical isolators for laser applications are also highly desired, as are new ways to use silicon for coupling and packaging. (
  • Coherent's diode-pumped solid-state (DPSS) portfolio includes pulsed and short-pulsed Q-switched, modelocked, and CW lasers that enable a wide range of materials processing, scientific, and life sciences applications. (
  • This is a systematic, up-to-date guide to laser instrumentation for sensing and measurement in contemporary scientific, industrial, automotive and avionics applications. (
  • The text is recommended for chemists, biochemists, and chemical physicists who want to know more about lasers and its applications to their respective fields. (
  • Among its many accomplishments, Astanza is proud to be the exclusive tattoo removal laser provider for LaserAway , the Nation's Leader in Aesthetic Dermatology, and also a trusted laser provider for Homeboy Industries , the largest gang intervention and re-entry program and the #1 busiest laser tattoo removal provider in the world. (
  • The recent expansion in laser dermatology is both promising and exciting as the treatments available to derms and their patients continue to grow. (
  • Our latest edition of the Thales Laser Masterclass training developped in partnership with the Polytech Paris-Sud and Paris-Sud University, has successfully been held this autumn. (
  • Selected again for NASA's Mars exploration programme, Thales has now delivered the laser for the SuperCam instrument to the French space agency CNES, which is partnering NASA for Mars 2020. (
  • Thales laser installation has started and the customer has witnessed the first lasing effects. (
  • Thales has been awarded the title of Laser of the Future by the French National Space Agency (Centre National d'Etudes Spatiales - CNES) whereby Thales has developped the laser for the SUPERCAM instrument intended for the 2020 mission to Mars. (
  • As a key player on the Scientific Laser Marketplace, Thales has a large R&D activity to constantly release innovative solutions on the markets. (
  • Thales is proud to mention that the Bella project won 2 world-class awards in 2012 and 2013 and that its laser activity was recognized as the most innovative technology within the group in 2014. (
  • We have established strong and long-term relation with well-known laboratories and partners ensuring smooth research to industry transfer of new processes and lasers concepts. (
  • Present systems for enrichment processes using lasers fall into two categories: those in which the process medium is atomic uranium vapor and those in which the process medium is the vapor of a uranium compound. (
  • Common nomenclature for such processes include "first category- atomic vapor laser isotope separation (AVLIS or SILVA)" and "second category- molecular laser isotope separation (MLIS or MOLIS). (
  • We are now advancing into areas that suggest the possibility of assisting these tunneling processes with strong X-ray lasers," says Schützhold. (
  • As the benefits of smaller devices help improve the quality of life, the ability to manufacture these devices to the highest precision, reliability and traceability are more important than ever and laser micro-machining processes are playing a more important role. (
  • Are you interested in purchasing a soft-tissue laser within the next 6 months? (
  • Several lasers have clearance for hard tissue use on teeth. (
  • Lasers may be used to remove tissue in eye surgery as well. (
  • Study co-author Professor Frederik Claeyssens said, 'This is the first time we have been able to structure polylactide with such high resolution and the first time that direct laser writing has been applied to tissue engineering. (
  • Since that time, lasers have improved and many new types of laser have been developed, including those that can clot, cut or get rid of tissue. (
  • Changes or improvements to the skin have become more significant since lasers have the ability to reach deeper into the tissue than any other form of treatment. (
  • Quote: "Similarly, a 125mW HeNe laser, together with a receiver constructed from a 12 inch telescope and Photo-Multiplier-Tube, has been used in a one waycontact over 110 miles. (