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Conference on Lasers and Electro-Optics (CLEO)

作者： Tao Yuan S. Mickan JinZhou Xu D. Abbott X.-C. Zhang Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy NY USA Centre for Biomedical Engineering and Department of Electrocal Elctronic Engineering Adelaide University SA Australia

Summary from only given. We use an ultrafast laser which is focused to a very small spot on a ZnTe electro optical crystal so that THz waves are only generated in this region. The idea spatial resolution is close to t... 详细信息

关键词： Microscopy Mirrors Focusing Pump lasers Optical pumping Ultrafast optics Lenses Zinc compounds Phased arrays Optical arrays

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Passive and active glass waveguide devices utilizing silicon overlay grating

Passive and active glass waveguide devices utilizing silicon...

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Integrated Photonics Research, IPR 2002

作者： Kim, Jaeyoun Winick, Kim A. Florea, Catalin Department of Electrical Engineering and Computer Science University of Michigan 1301 heal Avenue Ann ArborMI48109 United States Applied Physics Program University of Michigan 1301 heal Avenue Ann ArborMI48109 United States

Bragg gratings fabricated on top of ion exchanged glass waveguides using PECVD-deposited silicon overlays are reported. The resulting Bragg gratings are characterized and transmission dips at 1536 nm in excess of 18 d... 详细信息

ISBN: (纸本)1557527229

关键词： Bragg gratings

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Biosensing of opioids using frog melanophores

Biosensing of opioids using frog melanophores

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作者： Karlsson, Annika M. Bjuhr, Katarina Testorf, Martin Öberg, P.Ake Lerner, Ethan Lundström, Ingemar Svensson, Samuel P.S Department of Medicine and Care Pharmacology Faculty of Health Sciences SE-581 85 Linköping Sweden Department of Biomedical Engineering Linköpings Universitet SE-581 85 Linköping Sweden Bunsen Rush Laboratories Dallas TX United States Department of Physics and Measurement Technology Applied Physics Linköpings Universitet SE-581 83 Linköping Sweden

Spectacular color changes of fishes, frogs and other lower vertebrates are due to the motile activities of specialized pigment containing cells. Pigment cells are interesting for biosensing purposes since they provide an easily monitored physiological phenomenon. Melanophores, containing dark brown melanin pigment granules, constitute an important class of chromatophores. Their melanin-filled pigment granules may be stimulated to undergo rapid dispersion throughout the melanophores (cells appear dark), or aggregation to the center of the melanophores (cells appear light). This simple physiological response can easily be measured in a photometer. Selected G protein coupled receptors can be functionally expressed in cultured frog melanophores. Here, we demonstrate the use of recombinant frog melanophores as a biosensor for the detection of opioids. Melanophores were transfected with the human opioid receptor 3 and used for opiate detection. The response to the opioid receptor agonist morphine and a synthetic opioid peptide was analyzed by absorbance readings in an aggregation assay. It was shown that both agonists caused aggregation of pigment granules in the melanophores, and the cells appeared lighter. The pharmacology of the expressed receptors was very similar to its mammalian counterpart, as evidenced by competitive inhibition by increasing concentrations of the opioid receptor inhibitor naloxone. Transfection of melanophores with selected receptors enables the creation of numerous melanophore biosensors, which respond selectively to certain substances. The melanophore biosensor has potential use for measurement of substances in body fluids such as saliva, blood plasma and urine. © 2002 Elsevier Science B.V. All rights reserved.

关键词： Biosensors

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Long-wavelength continuum generation about the second dispersion zero of a tapered fiber

Long-wavelength continuum generation about the second disper...

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Nonlinear Guided Waves and Their Applications, NLGW 2002

作者： Harbold, J.M. Ilday, F.O. Wise, F.W. Birks, T.A. Wadsworth, W.J. Chen, Z. Department of Applied Physics Cornell University 212 Clark Hall IthacaNY14SS3 United States Department of Physics University of Bath Claverton Down BathBA2 7AY United Kingdom Beckmann Laser Institute and Center for Biomedical Engineering University of California IrvineCA92612 United States

We demonstrate continuum generation at wavelengths longer than the zero-dispersion wavelength of ordinary fiber for the first time using a narrow-diameter tapered fiber. © 2000 Optical Society of America.

ISBN: (纸本)1557527237

关键词： Dispersion (waves)

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Continuous measurement of blood oxygen pressure using a fiber optic sensor based on phosphorescence quenching

Continuous measurement of blood oxygen pressure using a fibe...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： K. Hase S. Sakai K. Tsukada E. Sekizuka C. Oshio H. Minamitani Department of Applied Physics andPhysimJnfomatics Keio University Japan Department of Biomedical Engineering Keio University Japan Keio University Japan Oshio clinic Keio University Japan

Measuring oxygen pressure within an artery is essential for providing information on blood perfusion. Optic-sensor is particularly well suited for oxygen pressure measurement because electrolytic or magnetic changes of the environment do not affect the measurement. We developed a fiber optical sensor based on phosphorescence quenching method. The probe, Pd-meso-tetra-(4-carboxyphenyl)porphyrin, was immobilized to the silicone resin membrane, which has high oxygen permeability, and attached to the tip of POF (outer diameter: 500 /spl mu/m). The light source used for exciting the probe was a Nd:YAG-SH pulse laser (532 nm) and the phosphorescent emission was detected by a photomultiplier tube. The signal was fitted to a single exponential decay curve to acquire the time constant (life time), thereafter the oxygen pressure was calculated from Stern-Volmer relationship. The effectiveness of the sensor was obtained to measure the dissolved oxygen with high precision (correlation coefficient 0.999) and high response time (about 7 sec). In this study, measurement of oxygen pressure was also made in the femoral artery of the rat by using the developed sensor and it indicated that it was very useful to measure arterial oxygen pressure continuously.

关键词： Pressure measurement Blood Optical fiber sensors Phosphorescence Arteries Probes Optical sensors Particle measurements Resins Biomembranes

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Ventricular wall thickness and volume during hemodynamic collapse produced by AC leakage current

Ventricular wall thickness and volume during hemodynamic col...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： B.K. Hoffmeister B.S. Sheals A.L. de Jongh R.A. Malkin Department of Physics Rhodes College Memphis TN USA Joint Program in Biomedical Engineering University of Memphis and University of Tennessee Health Science Center Memphis TN USA

Medical equipment can unintentionally allow the flow of power line current through the patient causing complete hemodynamic collapse without fibrillation. This study tests the hypothesis that static wall thickening accompanies AC induced collapse via an isovolumic state. In 3 dogs, we delivered AC current stimulation ranging from 10-160 Hz and 10-1000 /spl mu/A to the right ventricle. A steerable, quadripolar catheter was placed in the apex of the left ventricle and deflected towards the basal region to measure left ventricular volume. Two dimensional, short-axis ultrasound images of the LV endocardial walls were recorded to measure wall thickness. Our results indicate that wall thickness during collapse is significantly greater than during systole (/spl Delta/ thickness =11.7/spl plusmn/12 mm, p<0.001) and diastole (/spl Delta/ thickness=23.6/spl plusmn/13 mm, p<0.001). In addition, the volume of the left ventricle is significantly smaller during collapse than the average volume during normal sinus rhythm (/spl Delta/ impedance=0.152/spl plusmn/0.006 no units, p<0.001).

关键词： Hemodynamics Leakage current Ultrasonic variables measurement biomedical equipment Testing Dogs Catheters Volume measurement Ultrasonic imaging Thickness measurement

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Left ventricular volume changes after defibrillation

Left ventricular volume changes after defibrillation

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： A.L. de Jongh B.S. Sheals D.K. Chau B.K. Hoffmeister R.A. Malkin Joint Graduate Program in Biomedical Engineering University of Memphis and University of Tennessee Health Science Center Memphis TN USA Department of Physics Rhodes College Memphis TN USA

A previous study has shown that the cross-sectional area of the left ventricular cavity (LV) increases immediately after defibrillation, suggesting that the defibrillation shock may cause relaxation. Since a single area slice may not reflect the entire myocardium, we wanted to test the relaxation hypothesis by evaluating volume. Ten to twenty defibrillation shocks were delivered in each of six dogs. A catheter was placed in the LV to measure intraventricular volume (IVV). Ultrasound images of the LV were recorded simultaneously with IVV. LV cavity area increased 13% (p<0.001) and IVV increased 4% (p<0.001) post-shock. Our results confirm that the heart is relaxing after defibrillation.

关键词： Defibrillation Electric shock Myocardium Testing Volume relaxation Dogs Catheters Volume measurement Ultrasonic variables measurement Ultrasonic imaging

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Three dimensional imaging using T-ray computed tomography

Three dimensional imaging using T-ray computed tomography

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Conference on Lasers and Electro-Optics (CLEO)

作者： B. Ferguson Shaohong Wang D. Gray D. Abbott X.-C. Zhang Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute RPI Troy NY USA Centre for Biomedical Engineering and Department of Electrical & Electronic Engineering Adelaide University SA Australia Technology Park Mawson Lakes Boulevard CRC for Sensor Signal and Information Processing Mawson Lakes SA Australia

Summary form only given. T-ray computed tomography imaging has significant potential in a number of applications. It is capable of reconstructing the 3D structure and frequency dependent far-infrared optical properties of an object. Using the reconstructed material properties different substances may be uniquely identified despite being hidden within other opaque structures. Applications of this technology are foreseen in non-destructive mail/packaging inspection, semiconductor testing, quality control of plastics and certain biomedical applications where the absorption of THz is not prohibitive.

关键词： Computed tomography Optical imaging Image reconstruction Frequency dependence biomedical optical imaging Material properties Postal services Plastic packaging Semiconductor device packaging Inspection

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Editorial the NanoBioWorld

IEEE Transactions on Nanobioscience

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IEEE Transactions on Nanobioscience 2002年第1期1卷 1-3页

作者： Ruggiero, Carmelina Curtis, Adam S. G. Craighead, Harold G. Galiana, Henrietta L. University of Genoa DIST 16145 Genoa Italy University of Glasgow Centre for Cell Engineering IBLS G12 8QQ Glasgow United Kingdom Cornell University Department of Engineering and Applied Physics Ithaca NY 14853-2501 United States McGill University Department of Biomedical Engineering Montreal Que. H3A 2A7 Canada

No abstract available

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A high frequency ultrasound array element using thermoelastic expansion in PDMS

A high frequency ultrasound array element using thermoelasti...

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IEEE Symposium (IUS) Ultrasonics

作者： T. Buma M. Spisar M. O'Donnell Applied Physics Program and Department of Biomedical Engineering University of Michigan Ann Arbor MI USA

ISBN: (纸本)0780371771

The thermoelastic effect was used to produce high frequency, broadband ultrasound in water. A pulsed diode laser, followed by an erbium doped fiber amplifier, was focused onto a light absorbing film deposited on a glass substrate. Conversion efficiency was improved by 18 dB using a polydimethylsiloxane (PDMS) film instead of a more commonly used metallic one. Radiation pattern measurements show that considerable energy is radiated at +/-45 degrees for frequencies beyond 75 MHz. These results show that the thermoelastic effect can be used to produce phased arrays for high frequency ultrasound imaging.

关键词： Frequency Ultrasonic imaging Thermoelasticity Phased arrays Pulsed laser deposition Optical pulses Pulse amplifiers Diode lasers Erbium Doped fiber amplifiers

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