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PubMedDate not supplied

Electron optic aspects of sonically disintegrated influenza virus A(H1N1).

Purified influenza virus A(H1N1) was sonicated in a continuous flow Ultrasonics F600 device at 20 kHz, 600 W. Electron optic examination of samples collected at different time intervals revealed morphologic alterations of the virus particles, gradually increasing in intensity: detachment of surface components, disruption of the viral corpuscles and of their constitutive elements, appearance of ghosts and of clustered viral components different in size and orientation.

Influenza A Virus, H1N1 Subtype↗
PubMed2001

Noninvasive and minimally-invasive optical monitoring technologies.

With recent advancements in micro-fabrication and nano-fabrication techniques as well as advancements in the photonics industry, there is now the potential to develop less invasive portable sensors for monitoring micronutrients and other substances used to assess overall health. There have been many technology innovations in the central laboratory for these substances for overall health status but the primary motivation for the research and development of a portable field instrument has come from a diabetic patient and market-driven desire to minimally invasively or noninvasively monitor glucose concentrations in vivo. Such a sensor system has the potential to significantly improve the quality of life for the estimated 16 million diabetics in this country by making routine glucose measurements less painful and more convenient. In addition, there is a critical need for the development of less invasive portable technologies to assess micronutrient status (iron, vitamin A, iodine and folate), environmental hazards (lead) and for other disease-related substances, such as billirubin for infant jaundice. Currently, over 100 small companies and universities are working to develop improved monitoring devices, primarily for glucose, and optical methods are a big part of these efforts. In this article many of these potentially less invasive and portable optical sensing technologies, which are currently under investigation, will be reviewed including optical absorption spectroscopy, polarimetry, Raman spectroscopy and fluorescence.

Child↗
PubMed2006

The Optical Dilator: a clear, over-the-scope bougie with sequential dilating segments.

PURPOSE: The safety and efficacy of esophageal dilation is enhanced when direct visualization is possible, tactile sensation and feedback from resistance is maintained, and multiple dilations with a single passage of the dilating device is an option. The InScope Optical Dilator (InScope, a Division of Ethicon Endo-Surgery, Inc, Cincinnati, Ohio) is a flexible, transparent bougie fitted over a standard endoscope, with 3 dilating segments allowing sequential dilation under direct visualization. We report our experience with this device in treating benign esophageal strictures. METHODS: Patients with solid food dysphagia due to peptic strictures or Schatzki's ring were studied by using a 27F or 29F endoscope. Based on stricture appearance and estimated luminal diameter, 1 of 3 dilator sizes was chosen: IN0216 (14-, 15-, and 16-mm dilating segments), IN0218 (16-, 17-, and 18-mm dilating segments), or IN0220 (18-, 19-, and 20-mm dilating segments). RESULTS: Twenty-six patients were dilated and included 17 peptic strictures and 9 Schatzki's rings. Before dilation, most patients reported difficulties with solids at every meal. Median improvement 3 weeks after dilation was rated by patients as "substantial relief." Patients rated the dilation experience as largely "not at all unpleasant" immediately after endoscopy and had no recollection at 3 weeks' follow-up. There were no complications. Endoscopists rated dilator use as typical of experience with other bougies, and visualization was rated as high. CONCLUSION: The Optical Dilator maintains the value of tactile sensation and the convenience of 3 dilating sizes for each passage of the instrument with the added benefit of direct visualization.

Adolescent↗
PubMedDate not supplied

Near-infrared fluorescent deoxyglucose analogue for tumor optical imaging in cell culture and living mice.

2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) has extensively been used for clinical diagnosis, staging, and therapy monitoring of cancer and other diseases. Nonradioactive glucose analogues enabling the screening of the glucose metabolic rate of tumors are of particular interest for anticancer drug development. A nonradioactive fluorescent deoxyglucose analogue may have many applications for both imaging of tumors and monitoring therapeutic efficacy of drugs in living animals and may eventually translate to clinical applications. We found that a fluorescent 2-deoxyglucose analogue, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG), can be delivered in several tumor cells via the glucose transporters (GLUTs). We therefore conjugated D-glucosamine with a near-infrared (NIR) fluorphor Cy5.5 and tested the feasibility of the Cy5.5-D-glucosamine (Cy5.5-2DG) conjugate for NIR fluorescence imaging of tumors in a preclinical xenograft animal model. Cy5.5-2DG was prepared by conjugating Cy5.5 monofunctional N-hydroxysuccinimide ester (Cy5.5-NHS) and D-glucosamine followed by high-performance liquid chromatography purification. The accumulation of Cy5.5-2DG and Cy5.5-NHS in different tumor cell lines at 37 and 4 degrees C were imaged using a fluorescence microscope. Tumor targeting and retention of Cy5.5-2DG and Cy5.5-NHS in a subcutaneous U87MG glioma and A375M melanoma tumor model were evaluated and quantified by a Xenogen IVIS 200 optical cooled charged-coupled device system. Fluorescence microscopy imaging shows that Cy5.5-2DG and Cy5.5-NHS are taken up and trapped by a variety of tumor cell lines at 37 degrees C incubation, while they exhibit marginal uptake at 4 degrees C. The tumor cell uptake of Cy5.5-2DG cannot be blocked by the 50 mM D-glucose, suggesting that Cy5.5-2DG may not be delivered in tumor cells by GLUTs. U87MG and A375M tumor localization was clearly visualized in living mice with both NIR fluorescent probes. Tumor/muscle contrast was clearly visible as early as 30 min postinjection (pi), and the highest U87MG tumor/muscle ratios of 2.81 +/- 0.10 and 3.34 +/- 0.23 were achieved 24 h pi for Cy5.5-2DG and Cy5.5-NHS, respectively. While as a comparison, the micropositron emission tomography imaging study shows that [18F]FDG preferentially localizes to the U87MG tumor, with resulting tumor/muscle ratios ranging from 3.89 to 4.08 after 30 min to 2 h postadministration of the probe. In conclusion, the NIR fluorescent glucose analogues, Cy5.5-2DG and Cy5.5-NHS, both demonstrate tumor-targeting abilities in cell culture and living mice. More studies are warranted to further explore their application for optical tumor imaging. To develop NIR glucose analogues with the ability to target GLUTs/hexokinase, it is highly important to select NIR dyes with a reasonable molecular size.

Animals↗
PubMed2005

An integrated disposable dye clad leaky waveguide sensor for micro-TAS applications.

An integrated, disposable, dye clad leaky waveguide (DCLW) device has been fabricated and tested for both refractive index and fluorescence detection in mu-TAS applications. The chip comprises the required flow geometry and optical coupling elements in a robust device that is relatively simple and inexpensive to fabricate. Disposable DCLW chips were fabricated at room temperature by spin-coating both the dye and silica sol-gel waveguiding layers on a polymer substrate which contained injection moulded grating coupler. These devices have been designed to increase the interaction of the evanescent field light at the channel wall and with the sample in the channel. The DCLW device has been used to detect changes in the refractive index of different percentages of glycerol solutions and to detect low concentrations down to 10(-12) M fluorescein using a grating coupler.

Journal Article↗
PubMed1996

New instrumentation for optical measuring of oxygen in gas or dissolved in liquids.

The optical oxygen sensor is a novel device for the determination of oxygen in gases or dissolved in liquids. It is based on the measurement principle of fluorescence quenching, which is completely different from that of polarographic oxygen sensors (today the most widespread devices of oxygen detection). The new instrument offers features and advantages, which render it not only a realistic alternative, but, for specific applications, make it superior to existing electrochemical methods. The system is based on low-cost semiconductor devices (light-emitting diodes, photodiodes, low-cost analogue and digital components) and new LED-compatible oxygen-sensitive membranes. The flow cell of the instrument may be thermostatted and the sensor can be calibrated by a simple two-point calibration procedure. The optical oxygen sensor is particularly suitable for measuring dissolved oxygen in respirometry, since no oxygen is consumed by the device and the signal is independent of sample flowrate or stirring speed. Typical fields of application are monitoring of oxygen in ground and drinking water, in process control in bioreactors and in breath gas and blood gas analysis.

Biosensing Techniques↗
PubMed1985

Photo-electric plethysmography as a monitoring device in anaesthesia. Application and interpretation.

The optical principle of photo-electric plethysmography is described and the clinical significance of changes in the amplitude of the plethysmogram discussed. Physiologically, changes in blood volume pulsations depend on the distensibility of the vessel wall as well as on the intravascular pulse pressure. The importance of both factors in the interpretation of changes in the arterial pulse amplitude is illustrated by examples from 500 continuous recordings. In addition, it is shown that changes in the height of ventilatory waves may be of diagnostic significance.

Anesthesia↗
PubMed2003

Long-path measurement of atmospheric NO2 with an obstruction flashlight and a charge-coupled-device spectrometer.

A novel method of differential optical absorption spectroscopy (DOAS) is proposed and demonstrated to monitor the concentration of atmospheric pollutant gas. In contrast to conventional DOAS measurements with continuous light sources, the present method relies on white flashlights such as aviation obstruction lights that are generally installed on tall constructions. A simple detection system is devised by means of a telescope and a compact CCD spectrometer. A path length of 5.5 km allows us to measure atmospheric NO2 concentration with a detection limit of approximately 1 part per billion. We also discuss the possibility of deriving the aerosol optical thickness through the horizontal atmosphere from this pulsed DOAS measurement.

Journal Article↗
PubMed1997

Simultaneous digitization of upper airway fiber-optic images and respiratory signals.

We developed an inexpensive and efficient method for simultaneously digitizing respiratory signals and fiber-optic images of the upper airway. The main components of the system are a fiber-optic scope, a charge coupled device video camera, and a personal computer equipped with a frame grabber and an A/D board. The frame grabber digitizes images at five frames per second while the A/D board samples six respiratory signals at 25 samples per second. Digitized images are saved only in the event that the user instructs the computer to do so in order to limit disk space requirements. A circular buffering technique provides continuous storage of the most recent 50 frames in frame grabber memory. This feature gives the user up to 10 seconds, following the beginning of a respiratory event, to initiate the saving of images to computer hard disk. A postacquisition program displays the data acquired during the sleep study and allows the user to interactively select images for subsequent upper airway area measurement. This system enables us to observe and quantify the dynamics of the upper airway during different breathing conditions with minimal time and cost. It is also a potential clinical tool to use to determine the site of obstruction during sleep in patients with obstructive sleep apnea.

Computers↗
PubMed2004

Broad-band UVB fiber-optic comb for the treatment of scalp psoriasis: a pilot study.

Abstract Background Scalp psoriasis is a frustrating condition with limited treatment options. Our objective was to test a new fiber-optic broad-band UVB comb device for the treatment of this condition. Methods Scalp psoriasis on adult subjects was treated three times a week for up to 12 weeks with a fiber-optic UVB comb. A minimum 50-cm(2) scalp area served as the control. Starting doses were based on the standard minimal erythema dose (MED) with increments up to 20% for subsequent treatments. Results Fourteen subjects completed the study without sunburn reactions or blisters. Treated sites showed a mean improvement in the modified PASI score of 3.6. The difference in the mean modified PASI scores between the control and treated sites was 3.9 (< 0.0001). Conclusions This fiber-optic broad-band UVB comb can safely and effectively treat scalp psoriasis.

Adult↗
PubMed2004

Navigation systems based on registration of endoscopic and CT-derived virtual images for bronchofiberoscopic procedures.

Bronchofiberoscopy is an essential diagnostic procedure in patients with lung cancer. Sampling methods employed during endoscopy of the respiratory tract are performed with the aim of diagnosis confirmation and staging. Transbronchial needle aspiration may be used for evaluation of lymph nodes neighbouring with trachea and bronchi. Many efforts have been undertaken to increase the sensitivity of this procedure including the application of endobronchial ultrasonography. In recent years several research groups have proposed models of navigating systems to provide computer assistance during bronchoscopic interventions. Although they have used different techniques, their objective was the same - enabling tracking location and movement of bronchofiberoscope tip with reference to previously-acquired computed tomography (CT) images. Since a fiber-optic bronchoscope is a rather long and flexible device, determination of its tip location is not an easy task. The adoption of optical tracking methods used in neurosurgery or laparoscopic surgery to endoscopy of the tracheobronchial tree is usually not possible. Another obstacle is related to the fact that bronchofiberoscopes usually have only one operational channel. This feature considerably limits the feasibility of navigation systems based on the use of small electromagnetic sensing devices or USG probes. The sources of positioning errors in such systems are respiratory movements and the lack of external referential coordinate system associated with the tracheobronchial tree.A promising option for development of a bronchoscopic guidance system is the application of image registration algorithms. Such an approach encompasses registration of endoscopic images to views derived from advanced imaging methods, e.g. CT. In the first step, reconstruction of a three-dimensional, endoluminal views is performed. Next, the position of the virtual camera in a CT-derived virtual model is determined using a complex multi-level image registering algorithm. This stage is the source of the greatest differences between proposed methods and a potential field for considerable improvements.This paper presents a review of recent as well as classical image registering methods used in navigation systems for bronchofiberoscopy. Details related to the selection of crucial elements of navigation systems based on image registering techniques, such as transformation, similarity criteria, matching and global optimization, are specified.

Algorithms↗
PubMed2006

Phase locking and in-phase supermode selection in monolithic multicore fiber lasers.

We report a compact multicore fiber laser that utilizes an all-fiber approach for phase locking and in-phase supermode selection. By splicing passive coreless fibers of controlled lengths to both ends of an active 19-core fiber, we demonstrate that the fundamental in-phase supermode can be selectively excited with a completely monolithic fiber device, instead of conventional free-space and bulk optics, to achieve phase-locked operation for a multiemitter laser device.

Journal Article↗
PubMed1985

Critical flicker frequencies in MS patients with normal or abnormal pattern VEP.

Critical flicker frequencies (CFF) were compared with the latencies of visual pattern reversal evoked potentials (VEP) in 2 groups of MS patients to evaluate the value of CFF in electrophysiological diagnostics of demyelination of the optic tract. A microprocessor-based device was constructed to obtain CFF thresholds with a 2-alternative forced-choice method. VEP latency was more frequently pathological than CFF, but CFF was abnormal in 2 optic neuritis patients with normal VEP. The frequency of pathological CFF and VEP was different in the patient group with a long history of MS compared with the new cases; in the freshly diagnosed group, CFF had a better diagnostic yield compared to the patients with a longer history.

Adolescent↗
PubMed2006

Liquid deformable mirror for high-order wavefront correction.

We propose and demonstrate a novel liquid deformable mirror, based on electrocapillary actuation, for high-order wavefront correction. The device consists of a two-dimensional array of vertically oriented microchannels filled with two immiscible liquids, an aqueous electrolyte, and a viscous dielectric liquid, where the dielectric liquid overfills the top end of the channel and forms a thin layer on top. To remedy the poor reflectivity of pure liquids, a free-floating reflective membrane or a dye-coated liquid can be used. The proposed device offers several advantages for adaptive optics applications. These advantages include a high number of actuators, high stroke dynamic range, low power dissipation, fast response time, an initially flat surface, and low cost. However, the device is mainly suitable for dynamic wavefront correction and is limited by its orientation.

Journal Article↗
PubMed1979

[Device for time lapse studies on living cells in vitro (author's transl)].

Optical components of an inverted microscope have been utilized to set up a device for the observation of living cells under phase contrast conditions. Time lapse recording is performed either by use of a super-8 movie-camera or by a 1/2 inch video device. A special design provides a high focal stability. Standard plastic culture flasks can be used for high optical quality recordings. Both types of recording require low light intensities which results in a minimal light induced cell damaging.

Animals↗
PubMed2006

Classification of macular and optic nerve disease by principal component analysis.

In this study, pattern electroretinography (PERG) signals were obtained by electrophysiological testing devices from 70 subjects. The group consisted of optic nerve and macular diseases subjects. Characterization and interpretation of the physiological PERG signal was done by principal component analysis (PCA). While the first principal component of data matrix acquired from optic nerve patients represents 67.24% of total variance, the first principal component of the macular patients data matrix represents 76.81% of total variance. The basic differences between the two patient groups were obtained with first principal component, obviously. In addition, the graphic of second principal component vs. first principal component of optic nerve and macular subjects was analyzed. The two patient groups were separated clearly from each other without any hesitation. This research developed an auxiliary system for the interpretation of the PERG signals. The stated results show that the use of PCA of physiological waveforms is presented as a powerful method likely to be incorporated in future medical signal processing.

Adult↗
PubMed2004

Plasma devices to guide and collimate a high density of MeV electrons.

The development of ultra-intense lasers has facilitated new studies in laboratory astrophysics and high-density nuclear science, including laser fusion. Such research relies on the efficient generation of enormous numbers of high-energy charged particles. For example, laser-matter interactions at petawatt (10(15) W) power levels can create pulses of MeV electrons with current densities as large as 10(12) A cm(-2). However, the divergence of these particle beams usually reduces the current density to a few times 10(6) A cm(-2) at distances of the order of centimetres from the source. The invention of devices that can direct such intense, pulsed energetic beams will revolutionize their applications. Here we report high-conductivity devices consisting of transient plasmas that increase the energy density of MeV electrons generated in laser-matter interactions by more than one order of magnitude. A plasma fibre created on a hollow-cone target guides and collimates electrons in a manner akin to the control of light by an optical fibre and collimator. Such plasma devices hold promise for applications using high energy-density particles and should trigger growth in charged particle optics.

Journal Article↗
PubMed1994

Clinical definition for multiple sclerosis treatment trials.

Clinically, the Schumacher Panel criteria remain the best set of diagnostic criteria. Two subsets therein are definable, i.e., exacerbating-remitting (ER) and chronic progressive (CP), with the latter subdivided into progressive from onset and secondarily progressive. A clinically stable stage can also be recognized. It has been customary in treatment trials to separate ER and CP patients. End point for the latter is a comparison of neurologic status at the end of the trial with that entry. A similar assessment can be made for ER patients. With this criterion both types could be included in a single study. One could also, though, treat the exacerbation in an acute study or assess whether exacerbations can be prevented in a long-term trial. Most clinicians no longer consider monophasic disease as multiple sclerosis (MS). Depending on clinical extent, such patients are divisible into acute disseminated encephalomyelitis, Devic disease, transverse myelopathy, or optic neuritis. Each subgroup could be studied as with an acute exacerbation or in long term as to whether future and different neurologic insults can be prevented. One measure of neurologic status is the Disability Status Scale (DSS), which grades clinical impairment due to MS on a 0 (normal) to 10 (death due to MS) basis. The expanded DSS (EDSS) subdivides each step 1 through 9 into two. Type and severity of neurologic impairment is defined by graded involvement in the following eight functional systems (FS): pyramidal, cerebellar, brainstem, sensory, bowel and bladder, visual, cerebral, and other. Frequency and severity of each FS correlates strongly with DSS scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗