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Full-Text Articles in Engineering
Trumpet Directivity From A Rotating Semicircular Array, Samuel D. Bellows, Joseph E. Avila, Timothy W. Leishman
Trumpet Directivity From A Rotating Semicircular Array, Samuel D. Bellows, Joseph E. Avila, Timothy W. Leishman
Directivity
The directivity function of a played musical instrument describes the angular dependence of its acoustic radiation and diffraction about the instrument, musician, and musician’s chair. Directivity influences sound in rehearsal, performance, and recording environments and signals in audio systems. Because high-resolution, spherically comprehensive measurements of played musical instruments have been unavailable in the past, the authors have undertaken research to produce and share such data for studies of musical instruments, simulations of acoustical environments, optimizations of microphone placements, and other applications. The authors acquired the data from repeated chromatic scales produced by a trumpet played at mezzo-forte in an anechoic …
Gamelan Gong Directivity Dataset, Samuel D. Bellows, Dallin T. Harwood, Kent L. Gee, Micah R. Shepherd
Gamelan Gong Directivity Dataset, Samuel D. Bellows, Dallin T. Harwood, Kent L. Gee, Micah R. Shepherd
Directivity
No abstract provided.
Average Speech Directivity, Samuel D. Bellows, Claire M. Pincock, Jennifer K. Whiting, Timothy W. Leishman
Average Speech Directivity, Samuel D. Bellows, Claire M. Pincock, Jennifer K. Whiting, Timothy W. Leishman
Directivity
Speech directivity describes the angular dependence of acoustic radiation from a talker’s mouth and nostrils and diffraction about his or her body and chair (if seated). It is an essential physical aspect of communication affecting sounds and signals in acoustical environments, audio, and telecommunication systems. Because high-resolution, spherically comprehensive measurements of live, phonetically balanced speech have been unavailable in the past, the authors have undertaken research to produce and share such data for simulations of acoustical environments, optimizations of microphone placements, speech studies, and other applications. The measurements included three male and three female talkers who repeated phonetically balanced passages …
Dynamic Light Scattering Optical Coherence Tomography To Probe Motion Of Subcellular Scatterers., Nico J J Arezza, Marjan Razani, Michael C Kolios
Dynamic Light Scattering Optical Coherence Tomography To Probe Motion Of Subcellular Scatterers., Nico J J Arezza, Marjan Razani, Michael C Kolios
Medical Biophysics Publications
Optical coherence tomography (OCT) is used to provide anatomical information of biological systems but can also provide functional information by characterizing the motion of intracellular structures. Dynamic light scattering OCT was performed on intact, control MCF-7 breast cancer cells and cells either treated with paclitaxel to induce apoptosis or deprived of nutrients to induce oncosis. Autocorrelations (ACs) of the temporal fluctuations of OCT intensity signals demonstrate a significant decrease in decorrelation time after 24 h in both the paclitaxel-treated and nutrient-deprived cell groups but no significant differences between the two groups. The acquired ACs were then used as input for …
Review Of Biomedical Čerenkov Luminescence Imaging Applications, Kaveh Tanha, Ali Mahmoud Pashazadeh, Brian W. Pogue
Review Of Biomedical Čerenkov Luminescence Imaging Applications, Kaveh Tanha, Ali Mahmoud Pashazadeh, Brian W. Pogue
Dartmouth Scholarship
Čerenkov radiation is a fascinating optical signal, which has been exploited for unique diagnostic biological sensing and imaging, with significantly expanded use just in the last half decade. Čerenkov Luminescence Imaging (CLI) has desirable capabilities for niche applications, using specially designed measurement systems that report on radiation distributions, radiotracer and nanoparticle concentrations, and are directly applied to procedures such as medicine assessment, endoscopy, surgery, quality assurance and dosimetry. When compared to the other imaging tools such as PET and SPECT, CLI can have the key advantage of lower cost, higher throughput and lower imaging time. CLI can also provide imaging …
Real-Time In Vivo Cherenkoscopy Imaging During External Beam Radiation Therapy, Rongxiao Zhang, David J. Gladstone, Lesley A. Jarvis, Rendall R. Strawbridge, P Jack Hoopes, Oscar D. Friedman, Adam K. Glaser, Brian W. Pogue
Real-Time In Vivo Cherenkoscopy Imaging During External Beam Radiation Therapy, Rongxiao Zhang, David J. Gladstone, Lesley A. Jarvis, Rendall R. Strawbridge, P Jack Hoopes, Oscar D. Friedman, Adam K. Glaser, Brian W. Pogue
Dartmouth Scholarship
Cherenkov radiation is induced when charged particles travel through dielectric media (such as biological tissue) faster than the speed of light through that medium. Detection of this radiation or excited luminescence during megavoltage external beam radiotherapy (EBRT) can allow emergence of a new approach to superficial dose estimation, functional imaging, and quality assurance for radiation therapy dosimetry. In this letter, the first in vivo Cherenkov images of a real-time Cherenkoscopy during EBRT are presented. The imaging system consisted of a time-gated intensified charge coupled device (ICCD) coupled with a commercial lens. The ICCD was synchronized to the linear accelerator to …
Oxygen Tomography By Čerenkov-Excited Phosphorescence During External Beam Irradiation, Rongxiao Zhang, Scott C. Davis, Jennifer-Lynn H. Demers, Adam K. Glaser, David J. Gladstone, Tatiana V. Esipova, Sergei A. Vinogradov, Brian W. Pogue
Oxygen Tomography By Čerenkov-Excited Phosphorescence During External Beam Irradiation, Rongxiao Zhang, Scott C. Davis, Jennifer-Lynn H. Demers, Adam K. Glaser, David J. Gladstone, Tatiana V. Esipova, Sergei A. Vinogradov, Brian W. Pogue
Dartmouth Scholarship
The efficacy of radiation therapy depends strongly on tumor oxygenation during irradiation. However, current techniques to measure this parameter in vivo do not facilitate routine monitoring in patients. Herein, we demonstrate a noninvasive method for tomographic imaging of oxygen partial pressure (pO2 ) in deep tissue using the phosphorescence decay of an oxygen-sensitive probe excited by Čerenkov radiation induced by external beam radiotherapy. Tissue-simulating scattering phantoms (60 mm diameter with a 20 mm anomaly) containing platinum(II)-G4 (PtG4), a dendritic porphyrin-based phosphor, whose phosphorescence is quenched in the presence of oxygen, were irradiated with a clinical linear accelerator. The …
Automated Identification Of Tumor Microscopic Morphology Based On Macroscopically Measured Scatter Signatures, Pilar Beatriz Garcia-Allende, Venkataramanan Krishnaswamy, P Jack Hoopes, Kimberley S. Samkoe, Olga M. Conde, Brian W. Pogue
Automated Identification Of Tumor Microscopic Morphology Based On Macroscopically Measured Scatter Signatures, Pilar Beatriz Garcia-Allende, Venkataramanan Krishnaswamy, P Jack Hoopes, Kimberley S. Samkoe, Olga M. Conde, Brian W. Pogue
Dartmouth Scholarship
An automated algorithm and methodology is presented to identify tumor-tissue morphologies based on broadband scatter data measured by raster scan imaging of the samples. A quasi-confocal reflectance imaging system was used to directly measure the tissue scatter reflectance in situ, and the spectrum was used to identify the scattering power, amplitude, and total wavelength-integrated intensity. Pancreatic tumor and normal samples were characterized using the instrument, and subtle changes in the scatter signal were encountered within regions of each sample. Discrimination between normal versus tumor tissue was readily performed using a K-nearest neighbor classifier algorithm. A similar approach worked …
Interpreting Hemoglobin And Water Concentration, Oxygen Saturation, And Scattering Measured In Vivo By Near-Infrared Breast Tomography, Subhadra Srinivasan, Brian W. Pogue, Shudong Jiang, Hamid Dehghani, Christine Kogel, Sandra Soho, Jennifer J. Gibson, Tor D. Tosteson, Steven P. Poplack, Keith D. Paulsen
Interpreting Hemoglobin And Water Concentration, Oxygen Saturation, And Scattering Measured In Vivo By Near-Infrared Breast Tomography, Subhadra Srinivasan, Brian W. Pogue, Shudong Jiang, Hamid Dehghani, Christine Kogel, Sandra Soho, Jennifer J. Gibson, Tor D. Tosteson, Steven P. Poplack, Keith D. Paulsen
Dartmouth Scholarship
Near-infrared spectroscopic tomography was used to measure the properties of 24 mammographically normal breasts to quantify whole-breast absorption and scattering spectra and to evaluate which tissue composition characteristics can be determined from these spectra. The absorption spectrum of breast tissue allows quantification of (i) total hemoglobin concentration, (ii) hemoglobin oxygen saturation, and (iii) water concentration, whereas the scattering spectrum provides information about the size and number density of cellular components and structural matrix elements. These property data were tested for correlation to demographic information, including subject age, body mass index, breast size, and radiographic …