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A quantitative coronary arteriographic technique is described utilizing 105-mm photospot angiography and a hand-held optical magnifying device. This technique is rapid, accurate, and reproducible. We feel this technique has potential in evaluating coronary responses to acute interventions and in the long term evaluation of progression or regression of atherosclerotic disease.
By means of a new optical device developed by Reiner, an "optical implantation" of 6 different bi- and multifocal intraocular lenses (MIOLs) was performed in 20 young healthy subjects, and results were compared with those of a monofocal reference IOL. The following parameters were investigated: distance and near visual acuity, depth of focus and contrast sensitivity. The median of distance visual acuity was 1.0 in all IOLs with the exception of a 7-zone refractive MIOL (0.75). Near acuity without near addition was 1.0 in all MIOL models; through focus curves of all MIOLs showed an increase in depth of focus with a typical two peak course. Contrast sensitivity at high contrasts was reduced for the 7-zone-model, but contrast sensitivity at low contrasts was significantly reduced for all MIOLs, except the 2- and 3-zone refractive models.
The frequent use of heavy eyeglasses by the angiographer has resulted in significant discomfort due to "sliding glasses." Described is the optical push device, which allows the angiographer to adjust eyeglasses comfortably while maintaining sterility.
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Mechanical flexure is a source of major failures in astronomical spectrographs, for which the reimaging of a focal-plane pinhole has to be maintained in position within a fraction of a CCD pixel that has dimensions of the order of 15 microm. The d.o.lo.res. (an acronym for device optimized for low resolution) spectrograph for the Italian national telescope, Galileo, showed displacements of the image of the pinhole more than 10 times greater than expected. The mechanical failure was overcome by the insertion of a passive optical wedge that can add an out-of-phase circle to the flexure ellipse. The results encourage the use of the gravitational eccentric correction optics (GECO) optical-gravitational device in all astronomical observations made with the d.o.lo.res. spectrograph.
A variable-sensitivity organic-photoconductive device has been developed by using a memory-type organic photoconductor. The device is composed of an input layer and a memory layer acting as a charge generation and a charge transport layer, respectively. A persistent high-sensitivity state, which corresponds to a modulation of synaptic weights in a neuron model, was obtained by blue light illumination. A photochemical reaction of thiomichler's ketone (TMK) in the memory layer was found to be responsible for the memory formation. As a potential application of this memory-type organic photoconductor to an optical neural device, 2-D pattern storage and calculations were performed successfully.
INTRODUCTION: In the past several years, overactive bladder and urinary incontinence have become recognized as an unmet therapeutic need. Some new pharmacologic treatments have recently been described, and new approaches are in development by a number of companies. For preclinical studies, accurate assessment of micturition patterns over a long period of time is important for successful new drug development. Current methodologies rely upon collecting urine in cups positioned upon force displacement transducers and either collecting very large digitized data files, or producing long polygraph tracings. METHODS: The methodology described in this paper utilized an optical device consisting of an infrared photodiode and a matched phototransistor as an electronic drop counter. The device can monitor the appearance of urine flow as it exits the bottom of a metabolic cage. RESULTS: Because the device only collects data when there is an event, the resulting data files are significantly smaller, and there is no need to assure that the urine collection cups do not fill-up and overflow. Data were collected using both methodologies and the results compared. In every experiment, the data derived from the optical device were in very close agreement with the actual micturition pattern recorded by the cup-force transducer method. DISCUSSION: This optical method represents a simple and reliable technique for monitoring micturition patterns in experimental animals.
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Astigmatism poses a number of special difficulties when attempting to achieve a desirable refractive outcome during cataract surgery and intraocular lens implantation. One of the most pertinent difficulties is that traditional Gaussian theoretical formulas are simply unable to handle general astigmatic optical systems, that is, systems in which the principal meridians of the refracting interfaces do not lie in two mutually orthogonal planes. This means that the traditional approach falls short when the cornea is treated as bitoric or when other toric optical devices are already present in the eye. In this paper, the modified step-along procedure is utilized in a demonstration of the derivation of the traditional Gaussian theoretical formulas for the determination of intraocular lens power in a stigmatic eye. Matrices are then used to derive a general formula for the determination of the power of a thin toric intraocular lens in an astigmatic eye. This formula is then modified to allow the user to determine the power of the secondary intraocular lens required to compensate for any residual refraction in a phakic or pseudophakic astigmatic eye. The formulas hold under all conditions, including the case when the cornea is treated as thick and bitoric and when other toric optical devices are already present in the eye. Worked examples are provided.
Motion of abdominal organs with respiration is a major problem in NMR spectroscopy and imaging thereof. Triggering each phase-encoding step with respiration or gating a number of phase-encoding steps is one approach to the problem. The design of a sensor for small animal experiments has not been as simple. An optical device, implemented with polymer optical fibres is described, along with associated hardware and electronics which can act as a trigger for small animal NMR experiments. A brief description of a similar device for human application is also given. 2DFT spin-echo and B0 susceptibility images, both triggered and untriggered, are presented to validate the technique.
A new, to our knowledge, scheme of all-optical switching is put forward by use of an all-fiber Mach-Zehnder interferometer incorporating ytterbium-doped fiber Bragg gratings. The device utilizes the characteristics of the sharp change of group velocity in transmission with the detuning parameter, delta = 2pi n(1/lambda - 1/lambdaB). The switching is achieved by changing the Bragg wavelength of the ytterbium-doped arm of the interferometer. A very small shift of the Bragg wavelength can lead to a pi phase shift between the two arms, so the power needed to realize complete switching is much lower than that of other schemes. In addition, the device can compensate the dispersion of an optical pulse through the positive group velocity dispersion in transmission provided by the gratings.
UNLABELLED: Gastrointestinal intraluminal PCO2 (PiCO2) information is used to assess the adequacy of trauma patient resuscitation and to assist in choosing resuscitative interventions. Therefore, determining the limitations and potential caveats of different PiCO2 monitoring systems is clinically important. This study compared two PCO2 monitoring systems. The airflow device adds and then removes air samples to quantitate PCO2, whereas the fiber-optic device does not. METHODS: Airflow (TRIP Tonometer/Tonocap) and fiber-optic (Neotrend) systems were used. In vitro they were compared with each other and to two end-tidal CO2 monitors measuring the PCO2 of humidified air containing 5% and then 10% CO2. In vivo the two systems' catheters were surgically juxtaposed in 15 dogs' stomachs; paired PiCO2 readings were taken throughout hemorrhage and resuscitation. RESULTS: In vitro, paired PCO2 values from the airflow and fiber-optic devices correlated with each other (r = 0.99) and with end-tidal values (r = 0.99 with airflow, r = 0.95 with fiber-optic). In vivo, paired values differed significantly (P < 0.0001), correlating poorly for two devices simultaneously measuring the same variable (r = 0.61). Fiber-optic PiCO2 values were higher than airflow values (mmHg +/- SEM): 69.3 +/- 4.8 vs. 61.3 +/- 5.6 at the start of hemorrhage, 141.3 +/- 12.9 vs. 87.7 +/- 7.9 by end of hemorrhage, and 104.3 +/- 9.6 vs. 82.8 +/- 7.0 by end of resuscitation for fiber-optic and airflow, respectively. CONCLUSIONS: Despite agreement in vitro, airflow methods can influence PiCO2 values obtained in vivo. Passive sensing methods used to monitor PiCO2, such as fiber-optic methods, are preferable because they neither deliver O2 to, nor remove CO2 from the local microenvironment.
Head-trauma patients benefit from many optical and non-optical devices usually associated with low vision care. This article reviews the most common modifications of clinical examination techniques required to facilitate the evaluation of trauma patients who may benefit from or require low vision devices. A discussion of the importance of incorporating common optical and non-optical devices which can enhance the lives of traumatized patients will follow.
The optical information processing that takes place in an eye involves a large variety of very different optical components that are put together to solve a task which, in its basic nature, does not differ much from one species to another. The principal task of an eye is to sort the incoming photons so that they excite specific sensory neurons depending on angle of incidence, wavelength and plane of polarization. Despite the apparent simplicity of the task, the solutions to it are often complex and the variation between species is enormous. The pinhole camera, the Keplerian and Galilean telescopes, the corner reflector, optical fibres, and interference filters, are all names of optical devices invented by man. It now appears that all of these devices, and many more, exist in various combinations in the optics of invertebrate eyes. The similarity between man's and nature's optical engineering has been useful in many ways. For the study of eyes, it has helped to understand biological design principles in unparalleled detail.
Currently, optical devices, such as microscopes and CCD cameras, are utilized for identification of bullets and tool marks in the field of forensic science. While these optical methods are easily manageable and effective, they are under great influence of illumination condition. In other words, appearances of striations through these optical devices have possibility to be changed by lighting condition. Besides these appearance-based approaches, we can utilize three dimensional (3D) geometric data of tool marks that are free from lighting condition. In this study, we focused on 3D geometric data of landmark impressions on fired bullets for identification. We obtained the 3D surface data of tool marks by a confocal microscope and reconstructed virtual impressions on a PC monitor from the geometric data. Furthermore, the 3D data are exploited to numerical matching of two surface shapes. We also visualized the difference of two shapes. In order to do this, two surface models are aligned automatically. In this process, pairings of correspondent points on both surfaces are determined. Distance analysis between these pairs leads to a shape comparison. Since comparison results are visualized, they are intuitive and easily perceptive.
The difference between light reflected from the open eye and that reflected from the closed lid is detected by means of an optic fibre attached to a spectacle frame. That difference is processed electronically to produce a pulse train which may be interpreted either subjectively by a 'listener', or physically for the purpose of controlling external devices. Involuntary blinks may be suppressed. Potential developments of the technique are discussed.
Near-infrared-emitting rare-earth chelates based on 8-hydroxyquinoline have appeared frequently in recent literature, because they are promising candidates for active components in near-infrared-luminescent optical devices, such as optical amplifiers, organic light-emitting diodes, .... Unfortunately, the absence of a full structural investigation of these rare-earth quinolinates is hampering the further development of rare-earth quinolinate based materials, because the luminescence output cannot be related to the structural properties. After an elaborate structural elucidation of the rare-earth quinolinate chemistry we can conclude that basically three types of structures can be formed, depending on the reaction conditions: tris complexes, corresponding to a 1:3 metal-to-ligand ratio, tetrakis complexes, corresponding to a 1:4 metal-to-ligand ratio, and trimeric complexes, with a 3:8 metal-to-ligand ratio. The intensity of the emitted near-infrared luminescence of the erbium(III) complexes is highest for the tetrakis complexes of the dihalogenated 8-hydroxyquinolinates.