Free flexural vibrations of a piezoelectric bimorph plate with periodic edge conditions

This work analyzes the vibrations of a fully-electroded annular piezoelectric bimorph plate with a free inner edge and an outer edge that is built-in with a periodicity. To this end, a variational formulation with the extensive use of Lagrange multipliers for a bimorph plate with polar orthorhombic symmetry is performed first. The mechanical displacement and the electric potential that must satisfy constraint conditions at the electrodes are expanded as the sums of powers in the thickness coordinate. The resulting piezoelectric bimorph plate equations are used along with the introduction of appropriate Lagrange multipliers to analyze the polar orthorhombic annular sectorial plates with free radial and inner circumferential edges, and an entirely built-in or free outer edge. The results are then combined to obtain the solutions for the mixed boundary value problem. The extended Hamilton’s principle with the method of Lagrange multipliers is employed, followed by a Frobenius-type series expansion for solution functions. The eigensolutions are calculated from the resulting transcendental equation and compared with those obtained from an FEA to ensure the validity of the procedure

Real-time Near-infrared Virtual Intraoperative Surgical Photoacoustic Microscopy

AbstractWe developed a near infrared (NIR) virtual intraoperative surgical photoacoustic microscopy (NIR-VISPAM) system that combines a conventional surgical microscope and an NIR light photoacoustic microscopy (PAM) system. NIR-VISPAM can simultaneously visualize PA B-scan images at a maximum display rate of 45Hz and display enlarged microscopic images on a surgeon's view plane through the ocular lenses of the surgical microscope as augmented reality. The use of the invisible NIR light eliminated the disturbance to the surgeon's vision caused by the visible PAM excitation laser in a previous report. Further, the maximum permissible laser pulse energy at this wavelength is approximately 5 times more than that at the visible spectral range. The use of a needle-type ultrasound transducer without any water bath for acoustic coupling can enhance convenience in an intraoperative environment. We successfully guided needle and injected carbon particles in biological tissues ex vivo and in melanoma-bearing mice in vivo

Mouse neuroblastoma cell-based model and the effect of epileptic events on calcium oscillations and neural spikes

Recently, mouse neuroblastoma cells have been considered as an attractive model for the study of human neurological and prion diseases, and they have been intensively used as a model system in different areas. For example, the differentiation of neuro2a (N2A) cells, receptor-mediated ion current, and glutamate-induced physiological responses have been actively investigated with these cells. These mouse neuroblastoma N2A cells are of interest because they grow faster than other cells of neural origin and have a number of other advantages. The calcium oscillations and neural spikes of mouse neuroblastoma N2A cells in epileptic conditions are evaluated. Based on our observations of neural spikes in these cells with our proposed imaging modality, we reported that they can be an important model in epileptic activity studies. We concluded that mouse neuroblastoma N2A cells produce epileptic spikes in vitro in the same way as those produced by neurons or astrocytes. This evidence suggests that increased levels of neurotransmitter release due to the enhancement of free calcium from 4-aminopyridine causes the mouse neuroblastoma N2A cells to produce epileptic spikes and calcium oscillations.open0

Stimulated penetrating keratoplasty using real-time virtual intraoperative surgical optical coherence tomography

An intraoperative surgical microscope is an essential tool in a neuro-or ophthalmological surgical environment. Yet, it has an inherent limitation to classify subsurface information because it only provides the surface images. To compensate for and assist in this problem, combining the surgical microscope with optical coherence tomography (OCT) has been adapted. We developed a real-time virtual intraoperative surgical OCT (VISOCT) system by adapting a spectral-domain OCT scanner with a commercial surgical microscope. Thanks to our custommade beam splitting and image display subsystems, the OCT images and microscopic images are simultaneously visualized through an ocular lens or the eyepiece of the microscope. This improvement helps surgeons to focus on the operation without distraction to view OCT images on another separate display. Moreover, displaying the OCT live images on the eyepiece helps surgeon's depth perception during the surgeries. Finally, we successfully processed stimulated penetrating keratoplasty in live rabbits. We believe that these technical achievements are crucial to enhance the usability of the VISOCT system in a real surgical operating condition.open0

Real-time Near-infrared Virtual Intraoperative Surgical Photoacoustic Microscopy

We developed a near infrared (NIR) virtual intraoperative surgical photoacoustic microscopy (NIR-VISPAM) system that combines a conventional surgical microscope and an NIR light photoacoustic microscopy (PAM) system. NIR-VISPAM can simultaneously visualize PA B-scan images at a maximum display rate of 45 Hz and display enlarged microscopic images on a surgeon's view plane through the ocular lenses of the surgical microscope as augmented reality. The use of the invisible NIR light eliminated the disturbance to the surgeon's vision caused by the visible PAM excitation laser in a previous report. Further, the maximum permissible laser pulse energy at this wavelength is approximately 5 times more than that at the visible spectral range. The use of a needle-type ultrasound transducer without any water bath for acoustic coupling can enhance convenience in an intraoperative environment. We successfully guided needle and injected carbon particles in biological tissues ex vivo and in melanoma-bearing mice in vivo.open116Yscopu

Evaluation of the usefulness of three-dimensional optical coherence tomography in a guinea pig model of endolymphatic hydrops induced by surgical obliteration of the endolymphatic duct

Optical coherence tomography (OCT) has advanced significantly over the past two decades and is currently used extensively to monitor the internal structures of organs, particularly in ophthalmology and dermatology. We used ethylenediamine tetra-acetic acid (EDTA) to decalcify the bony walls of the cochlea and investigated the inner structures by deep penetration of light into the cochlear tissue using OCT on a guinea pig model of endolymphatic hydrops (EH), induced by surgical obliteration of the endolymphatic duct. The structural and functional changes associated with EH were identified using OCT and auditory brainstem response tests, respectively. We also evaluated structural alterations in the cochlea using three-dimensional reconstruction of the OCT images, which clearly showed physical changes in the cochlear structures. Furthermore, we found significant anatomical variations in the EH model and conducted graphical analysis by strial atrophy for comparison. The physical changes included damage to and flattening of the organ of Corti-evidence of Reissner's membrane distention-and thinning of the lateral wall. These results indicate that observation of EDTA-decalcified cochlea using OCT is significant in examination of gradual changes in the cochlear structures that are otherwise not depicted by hematoxylin and eosin staining © The Authorsopen0

Ultra-Fast Displaying Spectral Domain Optical Doppler Tomography System Using a Graphics Processing Unit

We demonstrate an ultrafast displaying Spectral Domain Optical Doppler Tomography system using Graphics Processing Unit (GPU) computing. The calculation of FFT and the Doppler frequency shift is accelerated by the GPU. Our system can display processed OCT and ODT images simultaneously in real time at 120 fps for 1,024 pixels x 512 lateral A-scans. The computing time for the Doppler information was dependent on the size of the moving average window, but with a window size of 32 pixels the ODT computation time is only 8.3 ms, which is comparable to the data acquisition time. Also the phase noise decreases significantly with the window size. Since the performance of a real-time display for OCT/ODT is very important for clinical applications that need immediate diagnosis for screening or biopsy. Intraoperative surgery can take much benefit from the real-time display flow rate information from the technology. Moreover, the GPU is an attractive tool for clinical and commercial systems for functional OCT features as well.open131

Performance of a Distributed Simultaneous Strain and Temperature Sensor Based on a Fabry-Perot Laser Diode and a Dual-Stage FBG Optical Demultiplexer

A simultaneous strain and temperature measurement method using a Fabry-Perot laser diode (FP-LD) and a dual-stage fiber Bragg grating (FBG) optical demultiplexer was applied to a distributed sensor system based on Brillouin optical time domain reflectometry (BOTDR). By using a Kalman filter, we improved the performance of the FP-LD based OTDR, and decreased the noise using the dual-stage FBG optical demultiplexer. Applying the two developed components to the BOTDR system and using a temperature compensating algorithm, we successfully demonstrated the simultaneous measurement of strain and temperature distributions under various experimental conditions. The observed errors in the temperature and strain measured using the developed sensing system were 0.6 °C and 50 με, and the spatial resolution was 1 m, respectively

Optical Sensing Method for Screening Disease in Melon Seeds by Using Optical Coherence Tomography

We report a noble optical sensing method to diagnose seed abnormalities using optical coherence tomography (OCT). Melon seeds infected with Cucumber green mottle mosaic virus (CGMMV) were scanned by OCT. The cross-sectional sensed area of the abnormal seeds showed an additional subsurface layer under the surface which is not found in normal seeds. The presence of CGMMV in the sample was examined by a blind test (n = 140) and compared by the reverse transcription-polymerase chain reaction. The abnormal layers (n = 40) were quantitatively investigated using A-scan sensing analysis and statistical method. By utilizing 3D OCT image reconstruction, we confirmed the distinctive layers on the whole seeds. These results show that OCT with the proposed data processing method can systemically pick up morphological modification induced by viral infection in seeds, and, furthermore, OCT can play an important role in automatic screening of viral infections in seeds

Development of a compact ICRF antenna for high-power and long-pulse plasma heating in the KSTAR

For the high-power and long-pulse ion cyclotron range of frequencies (ICRF) heating of the KSTAR plasma, we developed the compact ICRF antenna (CIA). The target injection power of CIA is 2 MW for 300 s. In order to continue injecting the power into plasma even if drastic instantaneous changes occur in the plasma condition, such as ELM events, we adopted the internal conjugate-T method for the load resilience. Between antenna heads and the junction point, impedance transformers were inserted to satisfy the condition of conjugate-T in a limited space keeping the electric field on the transformer low enough. To reduce the risk of water leakage into the vacuum chamber, only the backsides of antenna heads are water-cooled in the in-vessel region