Sample records for detecting focused ultrasound-induced

  1. In vivo transcranial cavitation threshold detection during ultrasound-induced bloodbrain barrier opening in mice

    E-print Network

    Konofagou, Elisa E.

    In vivo transcranial cavitation threshold detection during ultrasound-induced blood­brain barrier cavitation threshold detection during ultrasound-induced blood­brain barrier opening in mice Yao-Sheng Tung1 cavitation response associated with blood­brain barrier (BBB) opening as induced by transcranial focused

  2. Photoacoustic detection and optical spectroscopy of high-intensity focused ultrasound-induced thermal lesions in biologic tissue

    SciTech Connect

    Alhamami, Mosa; Kolios, Michael C.; Tavakkoli, Jahan, E-mail: jtavakkoli@ryerson.ca [Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada)] [Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada)

    2014-05-15

    Purpose: The aims of this study are: (a) to investigate the capability of photoacoustic (PA) method in detecting high-intensity focused ultrasound (HIFU) treatments in muscle tissuesin vitro; and (b) to determine the optical properties of HIFU-treated and native tissues in order to assist in the interpretation of the observed contrast in PA detection of HIFU treatments. Methods: A single-element, spherically concaved HIFU transducer with a centre frequency of 1 MHz was utilized to create thermal lesions in chicken breast tissuesin vitro. To investigate the detectability of HIFU treatments photoacoustically, PA detection was performed at 720 and 845 nm on seven HIFU-treated tissue samples. Within each tissue sample, PA signals were acquired from 22 locations equally divided between two regions of interest within two volumes in tissue – a HIFU-treated volume and an untreated volume. Optical spectroscopy was then carried out on 10 HIFU-treated chicken breast specimens in the wavelength range of 500–900 nm, in 1-nm increments, using a spectrophotometer with an integrating sphere attachment. The authors’ optical spectroscopy raw data (total transmittance and diffuse reflectance) were used to obtain the optical absorption and reduced scattering coefficients of HIFU-induced thermal lesions and native tissues by employing the inverse adding-doubling method. The aforementioned interaction coefficients were subsequently used to calculate the effective attenuation coefficient and light penetration depth of HIFU-treated and native tissues in the wavelength range of 500–900 nm. Results: HIFU-treated tissues produced greater PA signals than native tissues at 720 and 845 nm. At 720 nm, the averaged ratio of the peak-to-peak PA signal amplitude of HIFU-treated tissue to that of native tissue was 3.68 ± 0.25 (mean ± standard error of the mean). At 845 nm, the averaged ratio of the peak-to-peak PA signal amplitude of HIFU-treated tissue to that of native tissue was 3.75 ± 0.26 (mean ± standard error of the mean). The authors’ spectroscopic investigation has shown that HIFU-treated tissues have a greater optical absorption and reduced scattering coefficients than native tissues in the wavelength range of 500–900 nm. In fact, at 720 and 845 nm, the ratio of the optical absorption coefficient of HIFU-treated tissues to that of native tissues was 1.13 and 1.17, respectively; on the other hand, the ratio of the reduced scattering coefficient of HIFU-treated tissues to that of native tissues was 13.22 and 14.67 at 720 and 845 nm, respectively. Consequently, HIFU-treated tissues have a higher effective attenuation coefficient and a lower light penetration depth than native tissues in the wavelength range 500–900 nm. Conclusions: Using a PA approach, HIFU-treated tissues interrogated at 720 and 845 nm optical wavelengths can be differentiated from untreated tissues. Based on the authors’ spectroscopic investigation, the authors conclude that the observed PA contrast between HIFU-induced thermal lesions and untreated tissue is due, in part, to the increase in the optical absorption coefficient, the reduced scattering coefficient and, therefore, the deposited laser energy fluence in HIFU-treated tissues.

  3. Quasi-static elastography and its application in investigation of focused ultrasound induced tissue lesions

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Ling, Tao; Shen, Yong; Wang, Yan; Zheng, Hairong; Li, Faqi

    2012-10-01

    Monitoring of Focused Ultrasound (FUS) therapy has always been a key factor for a successful therapy. Although B-mode ultrasound has long been used for monitoring FUS therapy, the gray scale changes can not precisely reflect the lesion formation inside the tissue, while MR thermometry is considered to be too expensive. In this study, elastography had been performed using a commercial ultrasound system to investigate lesions produced by FUS irradiation in vitro. Several motion detection algorithms had been performed to improve the motion detection accuracy in the elastography. The effects of different algorithms on the motion detection accuracy were compared. Experimental results on the FUS induced lesion in swine muscle were introduced. The results indicated that lesions induced by small dosage of FUS inside the tissue can be successfully detected, which has a profound clinical meaning for the monitoring of FUS therapy.

  4. Detecting hepatic steatosis using ultrasound-induced thermal strain imaging: an ex vivo animal study

    PubMed Central

    Mahmoud, Ahmed M.; Ding, Xuan; Dutta, Debaditya; Singh, Vijay P.; Kim, Kang

    2014-01-01

    Hepatic steatosis or fatty liver disease occurs when lipids accumulate within the liver and can lead to steatohepatitis, cirrhosis, liver cancer, and eventual liver failure requiring liver transplant. Conventional brightness mode (B-mode) ultrasound (US) is the most common noninvasive diagnostic imaging modality used to diagnose hepatic steatosis in clinics. However, it is mostly subjective or requires a reference organ such as the kidney or spleen with which to compare. This comparison can be problematic when the reference organ is diseased or absent. The current work presents an alternative approach to noninvasively detecting liver fat content using ultrasound-induced thermal strain imaging (US-TSI). This technique is based on the difference in the change in the speed of sound as a function of temperature between water- and lipid-based tissues. US-TSI was conducted using two system configurations including a mid-frequency scanner with a single linear array transducer (5-14 MHz) for both imaging and heating and a high-frequency (13-24 MHz) small animal imaging system combined with a separate custom-designed US heating transducer array. Fatty livers (n=10) with high fat content (45.6 ± 11.7%) from an obese mouse model and control livers (n=10) with low fat content (4.8± 2.9%) from wild-type mice were embedded in gelatin. Then, US imaging was performed before and after US induced heating. Heating time periods of ~3 s and ~9.2 s were used for the mid-frequency imaging and high-frequency imaging systems, respectively to induce temperature changes of approximately 1.5 °C. The apparent echo shifts that were induced as a result of sound speed change were estimated using 2D phase-sensitive speckle tracking. Following US-TSI, histology was performed to stain lipids and measure percentage fat in the mouse livers. Thermal strain measurements in fatty livers (?0.065±0.079%) were significantly (p<0.05) higher than those measured in control livers (?0.124±0.037%). Using histology as a gold standard to classify mouse livers, US-TSI had a sensitivity and specificity of 70% and 90%, respectively. The area under the receiver operating characteristic (ROC) curve (AUC) was 0.775. This ex vivo study demonstrates the feasibility of using US-TSI to detect fatty livers and warrants further investigation of US-TSI as a diagnostic tool for hepatic steatosis. PMID:24487698

  5. Detecting hepatic steatosis using ultrasound-induced thermal strain imaging: an ex vivo animal study.

    PubMed

    Mahmoud, Ahmed M; Ding, Xuan; Dutta, Debaditya; Singh, Vijay P; Kim, Kang

    2014-02-21

    Hepatic steatosis or fatty liver disease occurs when lipids accumulate within the liver and can lead to steatohepatitis, cirrhosis, liver cancer and eventual liver failure requiring liver transplant. Conventional brightness mode (B-mode) ultrasound (US) is the most common noninvasive diagnostic imaging modality used to diagnose hepatic steatosis in clinics. However, it is mostly subjective or requires a reference organ such as the kidney or spleen with which to compare. This comparison can be problematic when the reference organ is diseased or absent. The current work presents an alternative approach to noninvasively detecting liver fat content using US-induced thermal strain imaging (US-TSI). This technique is based on the difference in the change in the speed of sound as a function of temperature between water- and lipid-based tissues. US-TSI was conducted using two system configurations including a mid-frequency scanner with a single linear array transducer (5-14 MHz) for both imaging and heating and a high-frequency (13-24 MHz) small animal imaging system combined with a separate custom-designed US heating transducer array. Fatty livers (n = 10) with high fat content (45.6 ± 11.7%) from an obese mouse model and control livers (n = 10) with low fat content (4.8 ± 2.9%) from wild-type mice were embedded in gelatin. Then, US imaging was performed before and after US induced heating. Heating time periods of ? 3 s and ? 9.2 s were used for the mid-frequency imaging and high-frequency imaging systems, respectively, to induce temperature changes of approximately 1.5 °C. The apparent echo shifts that were induced as a result of sound speed change were estimated using 2D phase-sensitive speckle tracking. Following US-TSI, histology was performed to stain lipids and measure percentage fat in the mouse livers. Thermal strain measurements in fatty livers (-0.065 ± 0.079%) were significantly (p < 0.05) higher than those measured in control livers (-0.124 ± 0.037%). Using histology as a gold standard to classify mouse livers, US-TSI had a sensitivity and specificity of 70% and 90%, respectively. The area under the receiver operating characteristic curve was 0.775. This ex vivo study demonstrates the feasibility of using US-TSI to detect fatty livers and warrants further investigation of US-TSI as a diagnostic tool for hepatic steatosis. PMID:24487698

  6. Targeted Drug Delivery with Focused Ultrasound-Induced Blood-Brain Barrier Opening Using Acoustically-Activated Nanodroplets

    PubMed Central

    Chen, Cherry C.; Sheeran, Paul S.; Wu, Shih-Ying; Olumolade, Oluyemi O.; Dayton, Paul A.; Konofagou, Elisa E.

    2013-01-01

    Focused ultrasound (FUS) in the presence of systemically administered microbubbles has been shown to locally, transiently and reversibly increase the permeability of the blood-brain barrier (BBB), thus allowing targeted delivery of therapeutic agents in the brain for the treatment of central nervous system diseases. Currently, microbubbles are the only agents that have been used to facilitate the FUS-induced BBB opening. However, they are constrained within the intravascular space due to their micron-size diameters, limiting the delivery effect at or near the microvessels. In the present study, acoustically-activated nanodroplets were used as a new class of contrast agents to mediate FUS-induced BBB opening in order to study the feasibility of utilizing these nanoscale phase-shift particles for targeted drug delivery in the brain. Significant dextran delivery was achieved in the mouse hippocampus using nanodroplets at clinically relevant pressures. Passive cavitation detection was used in the attempt to establish a correlation between the amount of dextran delivered in the brain and the acoustic emission recorded during sonication. Conventional microbubbles with the same lipid shell composition and perfluorobutane core as the nanodroplets were also used to compare the efficiency of FUS-induced dextran delivery. It was found that nanodroplets had a higher BBB opening pressure threshold but a lower stable cavitation threshold than microbubbles, suggesting that contrast agent-dependent acoustic emission monitoring was needed. More homogeneous dextran delivery within the targeted hippocampus was achieved using nanodroplets without inducing inertial cavitation or compromising safety. Our results offered a new means of developing the FUS-induced BBB opening technology for potential extravascular targeted drug delivery in the brain, extending the potential drug delivery region beyond the cerebral vasculature. PMID:24096019

  7. Feasibility of optoacoustic visualization of high-intensity focused ultrasound-induced thermal lesions in live tissue

    Microsoft Academic Search

    Parag V. Chitnis; Hans-Peter Brecht; Richard Su; Alexander A. Oraevsky

    2010-01-01

    A 3-D optoacoustic imaging system was used to visualize thermal lesions produced in vivo using high-intensity focused ultrasound (HIFU). A 7.5-MHz, surgical, focused transducer with a radius of curvature of 35 mm and an aperture diameter of 23 mm was used to generate HIFU. A pulsed laser, which could operate at 755 nm and 1064 nm, was used to illuminate

  8. Effects of Acoustic Parameters and Ultrasound Contrast Agent Dose on Focused-Ultrasound Induced Blood-Brain Barrier Disruption

    Microsoft Academic Search

    Nathan McDannold; Natalia Vykhodtseva; Kullervo Hynynen

    2008-01-01

    Previously, it was shown that low-intensity focused ultrasound pulses applied along with an ultrasound contrast agent results in temporary blood-brain barrier (BBB) disruption. This effect could be used for targeted drug delivery in the central nervous system. This study examined the effects of burst length, pulse repetition frequency (PRF), and ultrasound contrast agent dose on the resulting BBB disruption. One

  9. Imaging of high-intensity focused ultrasound-induced lesions in soft biological tissue using thermoacoustic tomography

    E-print Network

    Wang, Lihong

    thermoacoustic tomography Xing Jin, Yuan Xu, and Lihong V. Wanga) Optical Imaging Laboratory, Department December 2004) An imaging technology, thermoacoustic tomograpy (TAT), was applied to the visualization thermoacoustic sources in this tissue sample. The thermoacoustic signals were detected by an unfocused ultrasonic

  10. Feasibility of optoacoustic visualization of high-intensity focused ultrasound-induced thermal lesions in live tissue.

    PubMed

    Chitnis, Parag V; Brecht, Hans-Peter; Su, Richard; Oraevsky, Alexander A

    2010-01-01

    A 3-D optoacoustic imaging system was used to visualize thermal lesions produced in vivo using high-intensity focused ultrasound (HIFU). A 7.5-MHz, surgical, focused transducer with a radius of curvature of 35 mm and an aperture diameter of 23 mm was used to generate HIFU. A pulsed laser, which could operate at 755 nm and 1064 nm, was used to illuminate excised tissue and mice using a bifurcated fiber bundle resulting in two wide beams of light. Tomographic images were obtained while the specimens were rotated within a sphere outlined by a concave arc-shaped array of 64 piezo-composite transducers. These images were then combined to reconstruct 3-D volume images (voxel resolution 0.5 mm), which were acquired before and after HIFU exposure. In vivo optoacoustic images acquired at 1064 nm provided visualization of HIFU lesions. The lesion was indicated by a negative optoacoustic contrast. The molecular nature of such contrast may possibly be associated with reduction of the optical absorption due to reduced concentration of blood, tissue dehydration, denaturation of proteins and porphyrins, and reduction of thermoacoustic efficiency in the thermally treated tissue. These preliminary results demonstrate the potential of optoacoustic imaging to assess and monitor the progress of HIFU therapy. PMID:20459235

  11. Feasibility of optoacoustic visualization of high-intensity focused ultrasound-induced thermal lesions in live tissue

    PubMed Central

    Chitnis, Parag V.; Brecht, Hans-Peter; Su, Richard; Oraevsky, Alexander A.

    2010-01-01

    A 3-D optoacoustic imaging system was used to visualize thermal lesions produced in vivo using high-intensity focused ultrasound (HIFU). A 7.5-MHz, surgical, focused transducer with a radius of curvature of 35 mm and an aperture diameter of 23 mm was used to generate HIFU. A pulsed laser, which could operate at 755 nm and 1064 nm, was used to illuminate excised tissue and mice using a bifurcated fiber bundle resulting in two wide beams of light. Tomographic images were obtained while the specimens were rotated within a sphere outlined by a concave arc-shaped array of 64 piezo-composite transducers. These images were then combined to reconstruct 3-D volume images (voxel resolution 0.5 mm), which were acquired before and after HIFU exposure. In vivo optoacoustic images acquired at 1064 nm provided visualization of HIFU lesions. The lesion was indicated by a negative optoacoustic contrast. The molecular nature of such contrast may possibly be associated with reduction of the optical absorption due to reduced concentration of blood, tissue dehydration, denaturation of proteins and porphyrins, and reduction of thermoacoustic efficiency in the thermally treated tissue. These preliminary results demonstrate the potential of optoacoustic imaging to assess and monitor the progress of HIFU therapy. PMID:20459235

  12. Focused Ultrasound-Induced Blood–Brain Barrier Opening to Enhance Temozolomide Delivery for Glioblastoma Treatment: A Preclinical Study

    PubMed Central

    Wei, Kuo-Chen; Chu, Po-Chun; Wang, Hay-Yan Jack; Huang, Chiung-Yin; Chen, Pin-Yuan; Tsai, Hong-Chieh; Lu, Yu-Jen; Lee, Pei-Yun; Tseng, I-Chou; Feng, Li-Ying; Hsu, Peng-Wei; Yen, Tzu-Chen; Liu, Hao-Li

    2013-01-01

    The purpose of this study is to assess the preclinical therapeutic efficacy of magnetic resonance imaging (MRI)-monitored focused ultrasound (FUS)-induced blood-brain barrier (BBB) disruption to enhance Temozolomide (TMZ) delivery for improving Glioblastoma Multiforme (GBM) treatment. MRI-monitored FUS with microbubbles was used to transcranially disrupt the BBB in brains of Fisher rats implanted with 9L glioma cells. FUS-BBB opening was spectrophotometrically determined by leakage of dyes into the brain, and TMZ was quantitated in cerebrospinal fluid (CSF) and plasma by LC-MS\\MS. The effects of treatment on tumor progression (by MRI), animal survival and brain tissue histology were investigated. Results demonstrated that FUS-BBB opening increased the local accumulation of dyes in brain parenchyma by 3.8-/2.1-fold in normal/tumor tissues. Compared to TMZ alone, combined FUS treatment increased the TMZ CSF/plasma ratio from 22.7% to 38.6%, reduced the 7-day tumor progression ratio from 24.03 to 5.06, and extended the median survival from 20 to 23 days. In conclusion, this study provided preclinical evidence that FUS BBB-opening increased the local concentration of TMZ to improve the control of tumor progression and animal survival, suggesting its clinical potential for improving current brain tumor treatment. PMID:23527068

  13. Pressure and microbubble size dependence study of focused ultrasound-induced blood-brain barrier opening reversibility in vivo

    NASA Astrophysics Data System (ADS)

    Samiotaki, Gesthimani; Vlachos, Fotios; Tung, Yao-Sheng; Feshitan, Jameel; Borden, Mark; Konofagou, Elisa E.

    2012-10-01

    Most currently available therapeutic compounds cannot cross the blood-brain barrier (BBB), and their delivery to the brain remains a critical impediment. Focused Ultrasound (FUS) in conjunction with systemically administered microbubbles has been shown to open the BBB locally, non-invasively and reversibly. In this study, we investigated the dependence of BBB opening's reversibility timeline on the peak-rarefactional pressure (PRP) varied from 0.30 MPa to 0.60 MPa and the microbubble size in mice in vivo. The microbubbles used were monodispersed with diameters of 1-2, 4-5 or 6-8 microns. The contrast agent's (Gd) diffusion was used to quantify the opening, in T1-weighted high resolution MR images acquired on the day of sonication and up to five days thereafter. The volume of opening was found to increase with both pressure and microbubble diameter. The duration required for closing was found to be proportional to the volume of opening on the day of opening, and ranged from 24 hours, for the 1-2 um and 0.45 MPa, to 5 days for the 6-8 um and higher PRPs. Overall, larger bubbles did not show significant differences, and the BBB-opened region reduced steadily and radially towards the focal region until complete reinstatement was achieved.

  14. Focused ultrasound-induced blood-brain barrier opening for non-viral, non-invasive, and targeted gene delivery.

    PubMed

    Lin, Chung-Yin; Hsieh, Han-Yi; Pitt, William G; Huang, Chiung-Yin; Tseng, I-Chou; Yeh, Chih-Kuang; Wei, Kuo-Chen; Liu, Hao-Li

    2015-08-28

    Focused ultrasound (FUS) exposure in the presence of microbubbles can temporally open the blood-brain barrier (BBB) and is an emerging technique for non-invasive brain therapeutic agent delivery. Given the potential to deliver large molecules into the CNS via this technique, we propose a reliable strategy to synergistically apply FUS-BBB opening for the non-invasive and targeted delivery of non-viral genes into the CNS for therapeutic purpose. In this study, we developed a gene-liposome system, in which the liposomes are designed to carry plasmid DNA (pDNA, containing luciferase reporter gene) to form a liposomal-plasmid DNA (LpDNA) complex. Pulsed FUS exposure was delivered to induce BBB opening (500-kHz, burst length=10ms, 1% duty cycle, PRF=1Hz). The longitudinal expression of luciferase was quantitated via an in vivo imaging system (IVIS). The reporter gene expression level was confirmed via immunoblotting, and histological staining was used to identify transfected cells via fluorescent microscopy. In a comparison of gene transduction efficiency, the LpDNA system showed better cell transduction than the pDNA system. With longitudinal observation of IVIS monitoring, animals with FUS treatment showed significant promotion of LpDNA release into the CNS and demonstrated enhanced expression of genes upon sonication with FUS-BBB opening, while both the luciferase and GDNF protein expression were successfully measured via Western blotting. The gene expression peak was observed at day 2, and the gene expression level was up to 5-fold higher than that in the untreated hemisphere (compared to a 1-fold increase in the direct-inject positive-control group). The transfection efficiency was also found to be LpDNA dose-dependent, where higher payloads of pDNA resulted in a higher transfection rate. Immunoblotting and histological staining confirmed the expression of reporter genes in glial cells as well as astrocytes. This study suggests that IV administration of LpDNA in combination with FUS-BBB opening can provide effective gene delivery and expression in the CNS, demonstrating the potential to achieve non-invasive and targeted gene delivery for treatment of CNS diseases. PMID:26071631

  15. In vivo transcranial cavitation threshold detection during ultrasound-induced blood-brain barrier opening in mice

    NASA Astrophysics Data System (ADS)

    Tung, Yao-Sheng; Vlachos, Fotios; Choi, James J.; Deffieux, Thomas; Selert, Kirsten; Konofagou, Elisa E.

    2010-10-01

    The in vivo cavitation response associated with blood-brain barrier (BBB) opening as induced by transcranial focused ultrasound (FUS) in conjunction with microbubbles was studied in order to better identify the underlying mechanism in its noninvasive application. A cylindrically focused hydrophone, confocal with the FUS transducer, was used as a passive cavitation detector (PCD) to identify the threshold of inertial cavitation (IC) in the presence of Definity® microbubbles (mean diameter range: 1.1-3.3 µm, Lantheus Medical Imaging, MA, USA). A vessel phantom was first used to determine the reliability of the PCD prior to in vivo use. A cerebral blood vessel was simulated by generating a cylindrical channel of 610 µm in diameter inside a polyacrylamide gel and by saturating its volume with microbubbles. The microbubbles were sonicated through an excised mouse skull. Second, the same PCD setup was employed for in vivo noninvasive (i.e. transdermal and transcranial) cavitation detection during BBB opening. After the intravenous administration of Definity® microbubbles, pulsed FUS was applied (frequency: 1.525 or 1.5 MHz, peak-rarefactional pressure: 0.15-0.60 MPa, duty cycle: 20%, PRF: 10 Hz, duration: 1 min with a 30 s interval) to the right hippocampus of twenty-six (n = 26) mice in vivo through intact scalp and skull. T1 and T2-weighted MR images were used to verify the BBB opening. A spectrogram was generated at each pressure in order to detect the IC onset and duration. The threshold of BBB opening was found to be at a 0.30 MPa peak-rarefactional pressure in vivo. Both the phantom and in vivo studies indicated that the IC pressure threshold had a peak-rarefactional amplitude of 0.45 MPa. This indicated that BBB opening may not require IC at or near the threshold. Histological analysis showed that BBB opening could be induced without any cellular damage at 0.30 and 0.45 MPa. In conclusion, the cavitation response could be detected without craniotomy in mice and IC may not be required for BBB opening at relatively low pressures.

  16. A quantitative pressure and microbubble-size dependence study of focused ultrasound-induced blood-brain barrier opening reversibility in vivo using MRI.

    PubMed

    Samiotaki, Gesthimani; Vlachos, Fotios; Tung, Yao-Sheng; Konofagou, Elisa E

    2012-03-01

    Focused ultrasound in conjunction with the systemic administration of microbubbles has been shown to open the blood-brain barrier (BBB) selectively, noninvasively and reversibly. In this study, we investigate the dependence of the BBB opening's reversibility on the peak-rarefactional pressure (0.30-0.60 MPa) as well as the microbubble size (diameters of 1-2, 4-5, or 6-8 ?m) in mice using contrast-enhanced T(1)-weighted (CE-T(1)) MR images (9.4 T). Volumetric measurements of the diffusion of Gd-DTPA-BMA into the brain parenchyma were used for the quantification of the BBB-opened region on the day of sonication and up to 5 days thereafter. The volume of opening was found to increase with both pressure and microbubble diameter. The duration required for closing was found to be proportional to the volume of opening on the day of opening, and ranged from 24 h, for the smaller microbubbles, to 5 days at high peak-rarefactional pressures. Overall, larger bubbles did not show significant differences. Also, the extent of BBB opening decreased radially towards the focal region until the BBB's integrity was restored. In the cases where histological damage was detected, it was found to be highly correlated with hyperintensity on the precontrast T(1) images. PMID:21858862

  17. A Quantitative Pressure and Microbubble-Size Dependence Study of Focused Ultrasound-Induced Blood-Brain Barrier Opening Reversibility in vivo Using MRI

    PubMed Central

    Samiotaki, Gesthimani; Vlachos, Fotios; Tung, Yao-Sheng; Konofagou, Elisa E.

    2011-01-01

    Focused Ultrasound (FUS) in conjunction with the systemic administration of microbubbles has been shown to open the blood-brain barrier (BBB) selectively, non-invasively and reversibly. In this study, we investigate the dependence of the BBB opening’s reversibility on the peak-rarefactional pressure (PRP) (0.30 MPa - 0.60 MPa) as well as the microbubble size (diameters of 1-2, 4-5 or 6-8 microns) in mice using contrast-enhanced T1-weighted (CE-T1) MR images (9.4 T). Volumetric measurements of the diffusion of Gd-DTPA-BMA into the brain parenchyma were used for the quantification of the BBB-opened region on the day of sonication and up to five days thereafter. The volume of opening was found to increase with both pressure and microbubble diameter. The duration required for closing was found to be proportional to the volume of opening on the day of opening, and ranged from 24 hours, for the smaller microbubbles, to 5 days for high PRPs. Overall, larger bubbles did not show significant differences. Also, the extent of BBB opening decreased radially towards the focal region until BBB’s integrity was restored. In the cases where histological damage was detected, it was found to be highly correlated with hyperintensity in the pre-contrast T1 images. PMID:21858862

  18. Dependence of the Reversibility of Focused-Ultrasound-Induced Blood–Brain Barrier Opening on Pressure and Pulse Length In Vivo

    PubMed Central

    Samiotaki, Gesthimani; Konofagou, Elisa E.

    2014-01-01

    The most challenging aspect of intravenously-administered drugs currently developed to treat central nervous system (CNS) diseases is their impermeability through the blood–brain barrier (BBB), a specialized vasculature system protecting the brain microenvironment. Focused ultrasound (FUS) in conjunction with systemically administered microbubbles has been shown to open the BBB locally, noninvasively, and reversibly. The objective of this study was to investigate the effect of FUS (center frequency: 1.5 MHz) pulse length (PL), ranging here from 67 µs to 6.7 ms, on the physiology of the FUS-induced BBB opening. Dynamic contrast-enhanced (DCE) and T1-weighted magnetic resonance imaging (MRI) were used to quantify the permeability changes using transfer rate (Ktrans) mapping, the volume of BBB opening (VBBB) and the reversibility timeline of the FUS-induced BBB opening, with the systemic administration of microbubbles at different acoustic pressures, ranging from 0.30 to 0.60 MPa. Permeability and volume of opening were both found to increase with the acoustic pressure and pulse length. At 67-µs PL, the opening pressure threshold was 0.45 MPa, with BBB opening characteristics similar to those induced with 0.60 MPa at the same PL, as well as with 0.67-ms PL/0.30 MPa. On average, these cases had Ktrans = 0.0049 ± 0.0014 min?1 and VBBB = 3.7 ± 4.3 mm3, and closing occurred within 8 h. The 6.7-ms PL/0.30 MPa induced similar opening with 0.67-ms PL/0.45 MPa, and a closing timeline of 24 to 48 h. On average, Ktrans was 0.0091 ± 0.0029 min?1 and VBBB was 14.13 ± 7.7 mm3 in these cases. Also, there were no significant differences between the 6.7-ms PL/0.45 MPa, 0.67-ms PL/0.60 MPa and 6.7-ms PL/0.60 MPa cases, yielding on average a Ktrans of 0.0100 ± 0.0023 min?1 and VBBB equal to 20.1 ± 5.7 mm3. Closing occurred within 48 to 72 h in these cases. Stacked histograms of the Ktrans provided further insight to the non-uniform spatial distribution of permeability changes and revealed a correlation with the closing timeline. These results also suggest a beneficial complementary relationship between the elongation of the PL and the decrease of the peak negative acoustic pressures, and vice versa. Linear regression between Ktrans and VBBB showed a good correlation fit. Also, the time required for closing linearly increased with VBBB. The volume rate of decrease was measured to be 11.4 ± 4.0 mm3 per day, suggesting that the closing timeline could be predicted from the initial volume of opening. Finally, no histological damage was detected in any of the cases 7 d post-FUS, indicating the safety of the methodology and parameters used. PMID:24158283

  19. Dependence of the reversibility of focused- ultrasound-induced blood-brain barrier opening on pressure and pulse length in vivo.

    PubMed

    Samiotaki, Gesthimani; Konofagou, Elisa E

    2013-11-01

    The most challenging aspect of intravenously-administered drugs currently developed to treat central nervous system (CNS) diseases is their impermeability through the blood-brain barrier (BBB), a specialized vasculature system protecting the brain microenvironment. Focused ultrasound (FUS) in conjunction with systemically administered microbubbles has been shown to open the BBB locally, noninvasively, and reversibly. The objective of this study was to investigate the effect of FUS (center frequency: 1.5 MHz) pulse length (PL), ranging here from 67 ?s to 6.7 ms, on the physiology of the FUS-induced BBB opening. Dynamic contrast-enhanced (DCE) and T1-weighted magnetic resonance imaging (MRI) were used to quantify the permeability changes using transfer rate (Ktrans) mapping, the volume of BBB opening (VBBB) and the reversibility timeline of the FUS-induced BBB opening, with the systemic administration of microbubbles at different acoustic pressures, ranging from 0.30 to 0.60 MPa. Permeability and volume of opening were both found to increase with the acoustic pressure and pulse length. At 67-?s PL, the opening pressure threshold was 0.45 MPa, with BBB opening characteristics similar to those induced with 0.60 MPa at the same PL, as well as with 0.67-ms PL/0.30 MPa. On average, these cases had Ktrans = 0.0049 ± 0.0014 min-1 and VBBB = 3.7 ± 4.3 mm(3), and closing occurred within 8 h. The 6.7-ms PL/0.30 MPa induced similar opening with 0.67-ms PL/0.45 MPa, and a closing timeline of 24 to 48 h. On average, Ktrans was 0.0091 ± 0.0029 min-1 and VBBB was 14.13 ± 7.7 mm(3) in these cases. Also, there were no significant differences between the 6.7-ms PL/0.45 MPa, 0.67-ms PL/0.60 MPa and 6.7-ms PL/0.60 MPa cases, yielding on average a Ktrans of 0.0100 ± 0.0023 min-1 and VBBB equal to 20.1 ± 5.7 mm(3). Closing occurred within 48 to 72 h in these cases. Stacked histograms of the Ktrans provided further insight to the nonuniform spatial distribution of permeability changes and revealed a correlation with the closing timeline. These results also suggest a beneficial complementary relationship between the elongation of the PL and the decrease of the peak negative acoustic pressures, and vice versa. Linear regression between Ktrans and VBBB showed a good correlation fit. Also, the time required for closing linearly increased with VBBB. The volume rate of decrease was measured to be 11.4 ± 4.0 mm3 per day, suggesting that the closing timeline could be predicted from the initial volume of opening. Finally, no histological damage was detected in any of the cases 7 d post-FUS, indicating the safety of the methodology and parameters used. PMID:24158283

  20. Jet formation and shock wave emission during collapse of ultrasound-induced cavitation bubbles and their role in the therapeutic applications of high-intensity focused ultrasound

    Microsoft Academic Search

    T. Ikeda; Y. Matsumoto

    2005-01-01

    The dynamics of inertial cavitation bubbles produced by short pulses of high-intensity focused ultrasound near a rigid boundary are studied to get a better understanding of the role of jet formation and shock wave emission during bubble collapse in the therapeutic applications of ultrasound. The bubble dynamics are investigated by high-speed photography with up to 2 million frames\\/s and acoustic

  1. Jet formation and shock wave emission during collapse of ultrasound-induced cavitation bubbles and their role in the therapeutic applications of high-intensity focused ultrasound.

    PubMed

    Brujan, E A; Ikeda, T; Matsumoto, Y

    2005-10-21

    The dynamics of inertial cavitation bubbles produced by short pulses of high-intensity focused ultrasound near a rigid boundary are studied to get a better understanding of the role of jet formation and shock wave emission during bubble collapse in the therapeutic applications of ultrasound. The bubble dynamics are investigated by high-speed photography with up to 2 million frames/s and acoustic measurements, as well as by numerical calculations. The significant parameter of this study is the dimensionless stand-off, gamma, which is defined as the distance of the bubble centre at its maximum expansion scaled by the maximum bubble radius. High-speed photography is applied to observe the bubble motion and the velocity of the liquid jet formed during bubble collapse. Hydrophone measurements are used to determine the pressure and the duration of the shock wave emitted during bubble rebound. Calculations yield the variation with time of the bubble wall, the maximum velocity and the kinetic energy of the re-entrant jet. The comparisons between experimental and numerical data are favourable with regard to both shape history and translational motion of the bubble. The acoustic energy constitutes the largest individual amount in the energy balance of bubble collapse. The ratio of the shock wave energy, measured at 10 mm from the emission centre, to the cavitation bubble energy was 1:2.4 at gamma = 1.55 and 1:3.5 at gamma = 1. At this distance, the shock wave pressure ranges from 0.122 MPa, at gamma = 1, to 0.162 MPa, at gamma = 1.55, and the temporal duration at the half maximum level is 87 ns. The maximum jet velocity ranges from 27 m s(-1), at gamma = 1, to 36 m s(-1), at gamma = 1.55. For gamma < 1.2, the re-entrant jet can generate an impact pressure on the nearby boundary larger than 50 MPa. We discuss the implications of the results for the therapeutic applications of high-intensity focused ultrasound. PMID:16204873

  2. Jet formation and shock wave emission during collapse of ultrasound-induced cavitation bubbles and their role in the therapeutic applications of high-intensity focused ultrasound

    NASA Astrophysics Data System (ADS)

    Brujan, E. A.; Ikeda, T.; Matsumoto, Y.

    2005-10-01

    The dynamics of inertial cavitation bubbles produced by short pulses of high-intensity focused ultrasound near a rigid boundary are studied to get a better understanding of the role of jet formation and shock wave emission during bubble collapse in the therapeutic applications of ultrasound. The bubble dynamics are investigated by high-speed photography with up to 2 million frames/s and acoustic measurements, as well as by numerical calculations. The significant parameter of this study is the dimensionless stand-off, ?, which is defined as the distance of the bubble centre at its maximum expansion scaled by the maximum bubble radius. High-speed photography is applied to observe the bubble motion and the velocity of the liquid jet formed during bubble collapse. Hydrophone measurements are used to determine the pressure and the duration of the shock wave emitted during bubble rebound. Calculations yield the variation with time of the bubble wall, the maximum velocity and the kinetic energy of the re-entrant jet. The comparisons between experimental and numerical data are favourable with regard to both shape history and translational motion of the bubble. The acoustic energy constitutes the largest individual amount in the energy balance of bubble collapse. The ratio of the shock wave energy, measured at 10 mm from the emission centre, to the cavitation bubble energy was 1:2.4 at ? = 1.55 and 1:3.5 at ? = 1. At this distance, the shock wave pressure ranges from 0.122 MPa, at ? = 1, to 0.162 MPa, at ? = 1.55, and the temporal duration at the half maximum level is 87 ns. The maximum jet velocity ranges from 27 m s-1, at ? = 1, to 36 m s-1, at ? = 1.55. For ? < 1.2, the re-entrant jet can generate an impact pressure on the nearby boundary larger than 50 MPa. We discuss the implications of the results for the therapeutic applications of high-intensity focused ultrasound.

  3. High-intensity focused ultrasound-induced, localized mild hyperthermia to enhance anti-cancer efficacy of systemic doxorubicin: an experimental study.

    PubMed

    Chae, Sun Young; Kim, Young-sun; Park, Min Jung; Yang, Jehoon; Park, Hajan; Namgung, Mi-Sun; Rhim, Hyunchul; Lim, Hyo Keun

    2014-07-01

    The aim of this study was to evaluate the enhancement of the efficacy of systemic doxorubicin by pulsed high-intensity focused ultrasound (HIFU)-induced, localized mild hyperthermia. For the in vitro study, the intranuclear uptake of doxorubicin by squamous cell carcinoma (SCC)-7 cells incubated at different temperatures was compared. For the in vivo study, mice with SCC-7 tumors were assigned to either the control, conventional hyperthermia, HIFU hyperthermia, doxorubicin-alone, conventional hyperthermia + doxorubicin or HIFU hyperthermia + doxorubicin group. Conventional hyperthermia was induced by immersing the tumor in warm water (42.5°C), and HIFU hyperthermia was induced by HIFU after optimizing the parameters with direct temperature measurements (frequency = 1 MHz, pulse repetition frequency = 5 Hz, power = 12 W, duty cycle = 50%). In the in vitro study, fluorescence was more intense at 42°C than at 37°C and was time dependent. In the in vivo study, tumor growth in the HIFU hyperthermia + doxorubicin group was most prominently suppressed with the highest apoptotic index compared with all other groups (p < 0.05). Pulsed HIFU-induced localized mild hyperthermia enhanced the anti-cancer efficacy of systemic doxorubicin more than conventional mild hyperthermia. PMID:24642222

  4. Noninvasive localized delivery of Herceptin to the mouse brain by MRI-guided focused ultrasound-induced blood-brain barrier disruption

    NASA Astrophysics Data System (ADS)

    Kinoshita, Manabu; McDannold, Nathan; Jolesz, Ferenc A.; Hynynen, Kullervo

    2006-08-01

    Antibody-based anticancer agents are promising chemotherapeutic agents. Among these agents, Herceptin (trastuzumab), a humanized anti-human epidermal growth factor receptor 2 (HER2/c-erbB2) monoclonal antibody, has been used successfully in patients with breast cancer. However, in patients with brain metastasis, the blood-brain barrier limits its use, and a different delivery method is needed to treat these patients. Here, we report that Herceptin can be delivered locally and noninvasively into the mouse central nervous system through the blood-brain barrier under image guidance by using an MRI-guided focused ultrasound blood-brain barrier disruption technique. The amount of Herceptin delivered to the target tissue was correlated with the extent of the MRI-monitored barrier opening, making it possible to estimate indirectly the amount of Herceptin delivered. Histological changes attributable to this procedure were minimal. This method may represent a powerful technique for the delivery of macromolecular agents such as antibodies to treat patients with diseases of the central nervous system. brain tumor | microbubble

  5. Drug delivery to the brain by focused ultrasound induced blood-brain barrier disruption: quantitative evaluation of enhanced permeability of cerebral vasculature using two-photon microscopy.

    PubMed

    Nhan, Tam; Burgess, Alison; Cho, Eunice E; Stefanovic, Bojana; Lilge, Lothar; Hynynen, Kullervo

    2013-11-28

    Reversible and localized blood-brain barrier disruption (BBBD) using focused ultrasound (FUS) in combination with intravascularly administered microbubbles (MBs) has been established as a non-invasive method for drug delivery to the brain. Using two-photon fluorescence microscopy (2 PFM), we imaged the cerebral vasculature during BBBD and observed the extravasation of fluorescent dye in real-time in vivo. We measured the enhanced permeability upon BBBD for both 10 kDa and 70 kDa dextran conjugated Texas Red (TR) at the acoustic pressure range of 0.2-0.8 MPa and found that permeability constants of TR10 kDa and TR70 kDa vary from 0.0006 to 0.0359 min(-1) and from 0.0003 to 0.0231 min(-1), respectively. For both substances, a linear regression was applied on the permeability constant against the acoustic pressure and the slope from best-fit was found to be 0.039 ± 0.005 min(-1)/MPa and 0.018 ± 0.005 min(-1)/MPa, respectively. In addition, the pressure threshold for successfully induced BBBD was confirmed to be 0.4-0.6MPa. Finally, we identified two types of leakage kinetics (fast and slow) that exhibit distinct permeability constants and temporal disruption onsets, as well as demonstrated their correlations with the applied acoustic pressure and vessel diameter. Direct assessment of vascular permeability and insights on its dependency on acoustic pressure, vessel size and leakage kinetics are important for treatment strategies of BBBD-based drug delivery. PMID:24008151

  6. Real-time prediction of the reversibility of the ultrasound-induced blood-brain barrier opening using passive cavitation detection with MRI validation

    E-print Network

    Konofagou, Elisa E.

    using passive cavitation detection with MRI validation Tao Sun1 , Gesthimani Samiotaki1 and Elisa E, represented by the cavitation dose, as monitored during BBB opening to the reversibility of BBB opening). A single-element, pulse-echo ultrasound transducer served as a passive cavitation detector was used

  7. Prediction of the reversibility of the ultrasound-induced blood-brain barrier opening using passive cavitation detection with magnetic resonance imaging

    E-print Network

    Konofagou, Elisa E.

    cavitation detection with magnetic resonance imaging validation Tao Sun1 , Gesthimani Samiotaki1 and Elisa E (diameters: 1-2, 4-5, or 6-8 m). A 10-MHz passive cavitation detector was used to acquire cavitation signals that the stable cavitation dose increased with the number of days required for closing while it reached a plateau

  8. Ultrasound-Induced Disruption of Amphiphilic Block Copolymer Micelles

    E-print Network

    Zhao, Yue

    Ultrasound-Induced Disruption of Amphiphilic Block Copolymer Micelles Juan Xuan, Maxime Pelletier study,[7] we found that micelles of an amphiphilic poly(ethylene oxide)-block-poly(2-tetrahydro- pyranyl

  9. Controlled Ultrasound-Induced Blood-Brain Barrier Disruption Using Passive Acoustic Emissions Monitoring

    PubMed Central

    Arvanitis, Costas D.; Livingstone, Margaret S.; Vykhodtseva, Natalia; McDannold, Nathan

    2012-01-01

    The ability of ultrasonically-induced oscillations of circulating microbubbles to permeabilize vascular barriers such as the blood-brain barrier (BBB) holds great promise for noninvasive targeted drug delivery. A major issue has been a lack of control over the procedure to ensure both safe and effective treatment. Here, we evaluated the use of passively-recorded acoustic emissions as a means to achieve this control. An acoustic emissions monitoring system was constructed and integrated into a clinical transcranial MRI-guided focused ultrasound system. Recordings were analyzed using a spectroscopic method that isolates the acoustic emissions caused by the microbubbles during sonication. This analysis characterized and quantified harmonic oscillations that occur when the BBB is disrupted, and broadband emissions that occur when tissue damage occurs. After validating the system's performance in pilot studies that explored a wide range of exposure levels, the measurements were used to control the ultrasound exposure level during transcranial sonications at 104 volumes over 22 weekly sessions in four macaques. We found that increasing the exposure level until a large harmonic emissions signal was observed was an effective means to ensure BBB disruption without broadband emissions. We had a success rate of 96% in inducing BBB disruption as measured by in contrast-enhanced MRI, and we detected broadband emissions in less than 0.2% of the applied bursts. The magnitude of the harmonic emissions signals was significantly (P<0.001) larger for sonications where BBB disruption was detected, and it correlated with BBB permeabilization as indicated by the magnitude of the MRI signal enhancement after MRI contrast administration (R2?=?0.78). Overall, the results indicate that harmonic emissions can be a used to control focused ultrasound-induced BBB disruption. These results are promising for clinical translation of this technology. PMID:23029240

  10. Improved astigmatic focus error detection method

    NASA Technical Reports Server (NTRS)

    Bernacki, Bruce E.

    1992-01-01

    All easy-to-implement focus- and track-error detection methods presently used in magneto-optical (MO) disk drives using pre-grooved media suffer from a side effect known as feedthrough. Feedthrough is the unwanted focus error signal (FES) produced when the optical head is seeking a new track, and light refracted from the pre-grooved disk produces an erroneous FES. Some focus and track-error detection methods are more resistant to feedthrough, but tend to be complicated and/or difficult to keep in alignment as a result of environmental insults. The astigmatic focus/push-pull tracking method is an elegant, easy-to-align focus- and track-error detection method. Unfortunately, it is also highly susceptible to feedthrough when astigmatism is present, with the worst effects caused by astigmatism oriented such that the tangential and sagittal foci are at 45 deg to the track direction. This disclosure outlines a method to nearly completely eliminate the worst-case form of feedthrough due to astigmatism oriented 45 deg to the track direction. Feedthrough due to other primary aberrations is not improved, but performance is identical to the unimproved astigmatic method.

  11. Improved astigmatic focus error detection method

    NASA Astrophysics Data System (ADS)

    Bernacki, Bruce E.

    1992-03-01

    All easy-to-implement focus- and track-error detection methods presently used in magneto-optical (MO) disk drives using pre-grooved media suffer from a side effect known as feedthrough. Feedthrough is the unwanted focus error signal (FES) produced when the optical head is seeking a new track, and light refracted from the pre-grooved disk produces an erroneous FES. Some focus and track-error detection methods are more resistant to feedthrough, but tend to be complicated and/or difficult to keep in alignment as a result of environmental insults. The astigmatic focus/push-pull tracking method is an elegant, easy-to-align focus- and track-error detection method. Unfortunately, it is also highly susceptible to feedthrough when astigmatism is present, with the worst effects caused by astigmatism oriented such that the tangential and sagittal foci are at 45 deg to the track direction. This disclosure outlines a method to nearly completely eliminate the worst-case form of feedthrough due to astigmatism oriented 45 deg to the track direction. Feedthrough due to other primary aberrations is not improved, but performance is identical to the unimproved astigmatic method.

  12. Magnetoresistive flux focusing eddy current flaw detection

    NASA Technical Reports Server (NTRS)

    Wincheski, Russell A. (Inventor); Namkung, Min (Inventor); Simpson, John W. (Inventor)

    2005-01-01

    A giant magnetoresistive flux focusing eddy current device effectively detects deep flaws in thick multilayer conductive materials. The probe uses an excitation coil to induce eddy currents in conducting material perpendicularly oriented to the coil's longitudinal axis. A giant magnetoresistive (GMR) sensor, surrounded by the excitation coil, is used to detect generated fields. Between the excitation coil and GMR sensor is a highly permeable flux focusing lens which magnetically separates the GMR sensor and excitation coil and produces high flux density at the outer edge of the GMR sensor. The use of feedback inside the flux focusing lens enables complete cancellation of the leakage fields at the GMR sensor location and biasing of the GMR sensor to a location of high magnetic field sensitivity. In an alternate embodiment, a permanent magnet is positioned adjacent to the GMR sensor to accomplish the biasing. Experimental results have demonstrated identification of flaws up to 1 cm deep in aluminum alloy structures. To detect deep flaws about circular fasteners or inhomogeneities in thick multilayer conductive materials, the device is mounted in a hand-held rotating probe assembly that is connected to a computer for system control, data acquisition, processing and storage.

  13. Feasibility of using Nakagami distribution in evaluating the formation of ultrasound-induced thermal lesions.

    PubMed

    Zhang, Siyuan; Zhou, Fanyu; Wan, Mingxi; Wei, Min; Fu, Quanyou; Wang, Xing; Wang, Supin

    2012-06-01

    The acoustic posterior shadowing effects of bubbles influence the accuracy for defining the location and range of ablated thermal lesions during focused ultrasound surgery when using ultrasonic monitoring imaging. This paper explored the feasibility of using Nakagami distribution to evaluate the ablated region induced by focused ultrasound exposures at different acoustic power levels in transparent tissue-mimicking phantoms. The mean value of the Nakagami parameter m was about 0.5 in the cavitation region and increased to around 1 in the ablated region. Nakagami images were not subject to significant shadowing effects of bubbles. Ultrasound-induced thermal lesions observed in the photos and Nakagami images were overshadowed by bubbles in the B-mode images. The lesion size predicted in the Nakagami images was smaller than that predicted in the photos due to the sub resolvable effect of Nakagami imaging at the interface. This preliminary study on tissue-mimicking phantom suggested that the Nakagami parameter m may have the potential use in evaluating the formation of ultrasound-induced thermal lesion when the shadowing effect of bubbles is strong while the thermal lesion was small. Further studies in vivo and in vitro will be needed to evaluate the potential application. PMID:22712954

  14. Ultrasound induced by CW laser cavitation bubbles

    NASA Astrophysics Data System (ADS)

    Korneev, N.; Rodriguez Montero, P.; Ramos-García, R.; Ramirez-San-Juan, J. C.; Padilla-Martinez, J. P.

    2011-01-01

    The generation of ultrasound by a collapsing single cavitation bubble in a strongly absorbing liquid illuminated with a moderate power CW laser is described. The ultrasound shock wave is detected with hydrophone and interferometric device. To obtain a stronger pulse it is necessary to adjust a liquid absorption and a beam diameter. Their influence can be qualitatively understood with a simple model.

  15. Ultrasound-induced lung hemorrhage is not caused by inertial cavitation

    E-print Network

    Illinois at Urbana-Champaign, University of

    Ultrasound-induced lung hemorrhage is not caused by inertial cavitation William D. O'Brien, Jr to an inertial cavitation mechanism. The purpose of this article is to report the results of two experiments that directly contradict the hypothesis that ultrasound-induced lung hemorrhage is caused by inertial cavitation

  16. Comment on ``Ultrasound-induced lung hemorrhage is not caused by inertial cavitation''

    E-print Network

    Illinois at Urbana-Champaign, University of

    Comment on ``Ultrasound-induced lung hemorrhage is not caused by inertial cavitation'' [J. Acoust­1297 2000 that ultrasound-induced lung hemorrhage is not caused by inertial cavitation. An argument is provided that illustrates how cavitation inception conditions in the lungs of animals are not altered

  17. Hard x-ray focusing optics for concealed object detection

    NASA Astrophysics Data System (ADS)

    Jannson, Tomasz; Gertsenshteyn, Michael

    2006-05-01

    In this paper, we discuss hard x-ray optics, in general, and lobster-eye focusing optics, in particular, for concealed object detection, at longer distances. The longer distance (~50m) scenario is important for Improvised Explosives Detection (IED), "seeing through walls," "seeing objects under ground," and related applications.

  18. Visualization of ultrasound induced cavitation bubbles using the synchrotron x-ray Analyzer Based Imaging technique.

    PubMed

    Izadifar, Zahra; Belev, George; Izadifar, Mohammad; Izadifar, Zohreh; Chapman, Dean

    2014-12-01

    Observing cavitation bubbles deep within tissue is very difficult. The development of a method for probing cavitation, irrespective of its location in tissues, would improve the efficiency and application of ultrasound in the clinic. A synchrotron x-ray imaging technique, which is capable of detecting cavitation bubbles induced in water by a sonochemistry system, is reported here; this could possibly be extended to the study of therapeutic ultrasound in tissues. The two different x-ray imaging techniques of Analyzer Based Imaging (ABI) and phase contrast imaging (PCI) were examined in order to detect ultrasound induced cavitation bubbles. Cavitation was not observed by PCI, however it was detectable with ABI. Acoustic cavitation was imaged at six different acoustic power levels and six different locations through the acoustic beam in water at a fixed power level. The results indicate the potential utility of this technique for cavitation studies in tissues, but it is time consuming. This may be improved by optimizing the imaging method. PMID:25401957

  19. Comparison of ultrasound-induced bioeffects in glass catfish after injection with optison and liquid perflourocarbon droplets

    NASA Astrophysics Data System (ADS)

    Maruvada, Subha; Hynynen, Kullervo

    2003-04-01

    This work is an investigation of ultrasound-induced bioeffects in vivo. Glass catfish were used for these experiments because they are optically transparent. Anaesthetized fish were injected with either optison (OPT) or liquid perflourocarbon droplets (LPD), using microinjection techniques. Shortly after injection, the fish were insonified with one of two single element focused transducers (1.091 MHz and 0.747 MHz). An inverted microscope combined with a digital camera was used to optically monitor ultrasound interaction with the blood vessels in the tail of the fish at 200x magnification. The entire interaction was videotaped and digitized. The fish were insonified at power levels between 1-80 W, which translated into acoustic pressures from 0.45-15 MPa. Sonications were pulsed with burst lengths of 10 ms and 100 ms and a repetition frequency of 1 Hz. The entire length of one sonication at a specific pressure was 20 seconds. The effects of the sonication were analyzed at each pressure level. The ultrasound-induced bioeffects due to OPT and LPD were compared. Threshold values for damage were lower after OPT injection than after LPD injection, especially at lower frequencies.

  20. Attention focusing and anomaly detection in systems monitoring

    NASA Technical Reports Server (NTRS)

    Doyle, Richard J.

    1994-01-01

    Any attempt to introduce automation into the monitoring of complex physical systems must start from a robust anomaly detection capability. This task is far from straightforward, for a single definition of what constitutes an anomaly is difficult to come by. In addition, to make the monitoring process efficient, and to avoid the potential for information overload on human operators, attention focusing must also be addressed. When an anomaly occurs, more often than not several sensors are affected, and the partially redundant information they provide can be confusing, particularly in a crisis situation where a response is needed quickly. The focus of this paper is a new technique for attention focusing. The technique involves reasoning about the distance between two frequency distributions, and is used to detect both anomalous system parameters and 'broken' causal dependencies. These two forms of information together isolate the locus of anomalous behavior in the system being monitored.

  1. Preface to the Focus Issue: chaos detection methods and predictability.

    PubMed

    Gottwald, Georg A; Skokos, Charalampos

    2014-06-01

    This Focus Issue presents a collection of papers originating from the workshop Methods of Chaos Detection and Predictability: Theory and Applications held at the Max Planck Institute for the Physics of Complex Systems in Dresden, June 17-21, 2013. The main aim of this interdisciplinary workshop was to review comprehensively the theory and numerical implementation of the existing methods of chaos detection and predictability, as well as to report recent applications of these techniques to different scientific fields. The collection of twelve papers in this Focus Issue represents the wide range of applications, spanning mathematics, physics, astronomy, particle accelerator physics, meteorology and medical research. This Preface surveys the papers of this Issue. PMID:24985454

  2. Response to ``Comment on `Ultrasound-induced lung hemorrhage is not caused by inertial cavitation'''

    E-print Network

    Illinois at Urbana-Champaign, University of

    Response to ``Comment on `Ultrasound-induced lung hemorrhage is not caused by inertial cavitation cavitation nuclei in lung versus other tissues such that overpressure does not affect the inertial cavitation this question, let us first be clear as to what we believe would and would not constitute inertial cavitation

  3. Automated focusing in bright-field microscopy for tuberculosis detection

    PubMed Central

    OSIBOTE, O.A.; DENDERE, R.; KRISHNAN, S.; DOUGLAS, T.S.

    2010-01-01

    Summary Automated microscopy to detect Mycobacterium tuberculosis in sputum smear slides would enable laboratories in countries with a high tuberculosis burden to cope efficiently with large numbers of smears. Focusing is a core component of automated microscopy, and successful autofocusing depends on selection of an appropriate focus algorithm for a specific task. We examined autofocusing algorithms for bright-field microscopy of Ziehl–Neelsen stained sputum smears. Six focus measures, defined in the spatial domain, were examined with respect to accuracy, execution time, range, full width at half maximum of the peak and the presence of local maxima. Curve fitting around an estimate of the focal plane was found to produce good results and is therefore an acceptable strategy to reduce the number of images captured for focusing and the processing time. Vollath's F4 measure performed best for full z-stacks, with a mean difference of 0.27 ?m between manually and automatically determined focal positions, whereas it is jointly ranked best with the Brenner gradient for curve fitting. PMID:20946382

  4. Rotating flux-focusing eddy current probe for flaw detection

    NASA Technical Reports Server (NTRS)

    Wincheski, Russell A. (Inventor); Fulton, James P. (Inventor); Nath, Shridhar C. (Inventor); Simpson, John W. (Inventor); Namkung, Min (Inventor)

    1997-01-01

    A flux-focusing electromagnetic sensor which uses a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks about circular fasteners and other circular inhomogeneities in high conductivity material. The unique feature of the device is the ferrous shield isolating a high-turn pick-up coil from an excitation coil, The use of the magnetic shield is shown to produce a null voltage output across the receiving coil in the presence of an unflawed sample. A redistribution of the current flow in the sample caused by the presence of flaws, however, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal. By rotating the probe in a path around a circular fastener such as a rivet while maintaining a constant distance between the probe and the center of a rivet, the signal due to current flow about the rivet can be held constant. Any further changes in the current distribution, such as due to a fatigue crack at the rivet joint, can be detected as an increase in the output voltage above that due to the flow about the rivet head.

  5. Ultrasound-Induced Blood-Brain Barrier Opening

    PubMed Central

    Konofagou, Elisa E.; Tung, Yao-Sheng; Choi, James; Deffieux, Thomas; Baseri, Babak; Vlachos, Fotios

    2014-01-01

    Over 4 million U.S. men and women suffer from Alzheimer's disease; 1 million from Parkinson's disease; 350,000 from multiple sclerosis (MS); and 20,000 from amyotrophic lateral sclerosis (ALS). Worldwide, these four diseases account for more than 20 million patients. In addition, aging greatly increases the risk of neurodegenerative disease. Although great progress has been made in recent years toward understanding of these diseases, few effective treatments and no cures are currently available. This is mainly due to the impermeability of the blood-brain barrier (BBB) that allows only 5% of the 7000 small-molecule drugs available to treat only a tiny fraction of these diseases. On the other hand, safe and localized opening of the BBB has been proven to present a significant challenge. Of the methods used for BBB disruption shown to be effective, Focused Ultrasound (FUS), in conjunction with microbubbles, is the only technique that can induce localized BBB opening noninvasively and regionally. FUS may thus have a huge impact in trans-BBB brain drug delivery. The primary objective in this paper is to elucidate the interactions between ultrasound, microbubbles and the local microenvironment during BBB opening with FUS, which are responsible for inducing the BBB disruption. The mechanism of the BBB opening in vivo is monitored through the MRI and passive cavitation detection (PCD), and the safety of BBB disruption is assessed using H&E histology at distinct pressures, pulse lengths and microbubble diameters. It is hereby shown that the BBB can be disrupted safely and transiently under specific acoustic pressures (under 0.45 MPa) and microbubble (diameter under 8 ?m) conditions. PMID:22201586

  6. 7C-6 Motion Artifact Reduction by ECG Gating in Ultrasound Induced Thermal Strain Imaging

    Microsoft Academic Search

    K. Kim; S.-W. Huang; R. Olafsson; C. Jia; R. S. Witte; M. O'Donnell

    2007-01-01

    Cardiac motion related artifact in ultrasound induced thermal strain imaging (TSI) was reduced in-vitro and in-vivo using ECG gating. Tissue motion due to the heart beat is a major challenge for in-vivo TSI application, especially for cardiovascular systems. Temporal variation of the relative position between the transducer and the artery will induce decorrelation in speckle tracking. Tissue deformation produces mechanical

  7. Ultrasonic Sensitivity of Strain-Insensitive Fiber Bragg Grating Sensors and Evaluation of Ultrasound-Induced Strain

    PubMed Central

    Tsuda, Hiroshi; Kumakura, Kenji; Ogihara, Shinji

    2010-01-01

    In conventional ultrasound detection in structures, a fiber Bragg grating (FBG) is glued on or embedded in the structure. However, application of strain to the structure can influence the sensitivity of the FBG toward ultrasound and can prevent its effective detection. An FBG can work as a strain-insensitive ultrasound sensor when it is not directly glued to the monitored structure, but is instead applied to a small thin plate to form a mobile sensor. Another possible configuration is to affix an FBG-inscribed optical fiber without the grating section attached to the monitored structure. In the present study, sensitivity to ultrasound propagated through an aluminum plate was compared for a strain-insensitive FBG sensor and an FBG sensor installed in a conventional manner. Strains induced by ultrasound from a piezoelectric transducer and by quasi-acoustic emission of a pencil lead break were also quantitatively evaluated from the response amplitude of the FBG sensor. Experimental results showed that the reduction in the signal-to-noise ratio for ultrasound detection with strain-insensitive FBG sensors, relative to traditionally-installed FBG sensors, was only 6 dB, and the ultrasound-induced strain varied within a range of sub-micron strains. PMID:22163523

  8. Focal Delivery of AAV2/1-transgenes Into the Rat Brain by Localized Ultrasound-induced BBB Opening

    PubMed Central

    Alonso, Angelika; Reinz, Eileen; Leuchs, Barbara; Kleinschmidt, Jürgen; Fatar, Marc; Geers, Bart; Lentacker, Ine; Hennerici, Michael G.; de Smedt, Stefaan C.; Meairs, Stephen

    2013-01-01

    Delivery of drugs and macromolecules to the central nervous system (CNS) is hindered by the blood–brain barrier (BBB). Several approaches have been used to overcome this hindrance to facilitate the treatment of various CNS diseases. We now present results showing that chimeric adeno-associated virus 2/1 (AAV2/1) particles containing the coding region for the LacZ gene are efficiently delivered into the rat brain upon intravenous (IV) administration after BBB opening by focused ultrasound in the presence of vascular acoustic resonators. We show that the transgene is correctly and efficiently expressed in cells located in the neighborhood of the insonated focus, especially in the vicinity of small vessels and capillaries. Histochemical LacZ staining allows the identification of large amounts of cells expressing the enzymatically active protein. Using double immunofluorescence (IF) with antibodies against tubulinIII and bacterial LacZ, we identified these cells to be mostly neurons. A small proportion of the transduced cells was recognized as glial cells, reacting positive in the IF with antibodies against astrocytic markers. These results demonstrate that our approach allows a very specific, localized, and efficient expression of intravenously administered transgenes in the brain of rats upon ultrasound-induced BBB opening. PMID:23423361

  9. Focal Delivery of AAV2/1-transgenes Into the Rat Brain by Localized Ultrasound-induced BBB Opening.

    PubMed

    Alonso, Angelika; Reinz, Eileen; Leuchs, Barbara; Kleinschmidt, Jürgen; Fatar, Marc; Geers, Bart; Lentacker, Ine; Hennerici, Michael G; de Smedt, Stefaan C; Meairs, Stephen

    2013-01-01

    Delivery of drugs and macromolecules to the central nervous system (CNS) is hindered by the blood-brain barrier (BBB). Several approaches have been used to overcome this hindrance to facilitate the treatment of various CNS diseases. We now present results showing that chimeric adeno-associated virus 2/1 (AAV2/1) particles containing the coding region for the LacZ gene are efficiently delivered into the rat brain upon intravenous (IV) administration after BBB opening by focused ultrasound in the presence of vascular acoustic resonators. We show that the transgene is correctly and efficiently expressed in cells located in the neighborhood of the insonated focus, especially in the vicinity of small vessels and capillaries. Histochemical LacZ staining allows the identification of large amounts of cells expressing the enzymatically active protein. Using double immunofluorescence (IF) with antibodies against tubulinIII and bacterial LacZ, we identified these cells to be mostly neurons. A small proportion of the transduced cells was recognized as glial cells, reacting positive in the IF with antibodies against astrocytic markers. These results demonstrate that our approach allows a very specific, localized, and efficient expression of intravenously administered transgenes in the brain of rats upon ultrasound-induced BBB opening.Molecular Therapy - Nucleic Acids (2013) 2, e73; doi:10.1038/mtna.2012.64; published online 19 February 2013. PMID:23423361

  10. Ultrasound induced improvement in optical coherence tomography (OCT) resolution

    Microsoft Academic Search

    John O. Schenk; Mark E. Brezinski

    2002-01-01

    Optical coherence tomography (OCT) is a rapidly emerging technology for high-resolution biomedical imaging. The axial resolution of this technology is determined by the bandwidth of the source. Commercial sources generally provide resolutions of 10-20 mum whereas laboratory-based solid state lasers have resolutions of 4 mum. The resolution in tissue depends almost exclusively on detecting single scattered events. However, the phenomenon

  11. Ultrasound induced improvement in optical coherence tomography (OCT) resolution

    PubMed Central

    Schenk, John O.; Brezinski, Mark E.

    2002-01-01

    Optical coherence tomography (OCT) is a rapidly emerging technology for high-resolution biomedical imaging. The axial resolution of this technology is determined by the bandwidth of the source. Commercial sources generally provide resolutions of 10–20 ?m whereas laboratory-based solid state lasers have resolutions of ?4 ?m. The resolution in tissue depends almost exclusively on detecting single scattered events. However, the phenomenon known as multiple scattering results in a deterioration of resolution as a function of depth. In this study, OCT was combined with ultrasound in an attempt to reduce the effect of multiple scattering. The theory is that, with parallel ultrasound and OCT beams, multiply scattered light with a momentum component significantly perpendicular to the OCT beam will be reduced because the light is Doppler shifted outside the bandpass filter of the OCT detection electronics. A 7.5-MHz ultrasound transducer was used to introduce the photon/phonon interaction. A reflecting metal plate was placed within biological tissue, and the point spread function (PSF) was assessed off the reflector. The PSF was determined in the presence of no ultrasound, pulsed ultrasound, and continuous-wave (CW) ultrasound. CW ultrasound resulted in a 17% improvement (P < 0.001) in resolution and pulsed ultrasound resulted in 8% (P < 0.01). Image noise reduction could also be noted. Combining OCT with a parallel ultrasound beam results in an improvement in resolution through a reduced effect of multiple scattering due to photon/phonon interaction. With higher frequencies, better control of the acoustical beam, and tests in media with higher rates of multiple scattering, improved results are anticipated. PMID:12119391

  12. Ultrasound induced improvement in optical coherence tomography (OCT) resolution.

    PubMed

    Schenk, John O; Brezinski, Mark E

    2002-07-23

    Optical coherence tomography (OCT) is a rapidly emerging technology for high-resolution biomedical imaging. The axial resolution of this technology is determined by the bandwidth of the source. Commercial sources generally provide resolutions of 10-20 microm whereas laboratory-based solid state lasers have resolutions of approximately 4 microm. The resolution in tissue depends almost exclusively on detecting single scattered events. However, the phenomenon known as multiple scattering results in a deterioration of resolution as a function of depth. In this study, OCT was combined with ultrasound in an attempt to reduce the effect of multiple scattering. The theory is that, with parallel ultrasound and OCT beams, multiply scattered light with a momentum component significantly perpendicular to the OCT beam will be reduced because the light is Doppler shifted outside the bandpass filter of the OCT detection electronics. A 7.5-MHz ultrasound transducer was used to introduce the photon/phonon interaction. A reflecting metal plate was placed within biological tissue, and the point spread function (PSF) was assessed off the reflector. The PSF was determined in the presence of no ultrasound, pulsed ultrasound, and continuous-wave (CW) ultrasound. CW ultrasound resulted in a 17% improvement (P < 0.001) in resolution and pulsed ultrasound resulted in 8% (P < 0.01). Image noise reduction could also be noted. Combining OCT with a parallel ultrasound beam results in an improvement in resolution through a reduced effect of multiple scattering due to photon/phonon interaction. With higher frequencies, better control of the acoustical beam, and tests in media with higher rates of multiple scattering, improved results are anticipated. PMID:12119391

  13. Optical monitoring of ultrasound-induced bioeffects in glass catfish.

    PubMed

    Maruvada, Subha; Hynynen, Kullervo

    2004-01-01

    This study is an investigation of the therapeutic ultrasound (US) effects on the blood vessels of optically transparent fish in vivo. Although many investigators have characterized cavitation in vivo using remote-sensing methods (i.e., measuring the acoustic emissions caused by oscillating bubbles) very few have made direct observations of cavitation-induced damage. Anesthetized glass catfish, which are optically transparent, was injected with the contrast agent, Optison, and then insonified at pressures that ranged from 0.5-10 MPa (peak negative pressures). Two focused transducers were used in these experiments to cover a frequency range of 0.7-3.3 MHz. Sonications were pulsed with pulse durations of 100, 10, 1, 0.1 and 0.01 ms and a pulse repetition frequency (PRF) of 1 Hz. The entire length of one sonication at a specific pressure level was 20 s. An inverted microscope combined with a digital camera and video monitor were used optically to monitor and record US interaction with the blood vessels in the tail of the anesthetized fish at 200x magnification. The effects of the burst sonication were analyzed visually at each pressure level. For the 1.091-MHz sonications, the first type of damage that occurred due to the US interaction was structural damage to the cartilage rods that comprise the tail of the fish, and was characterized by a disintegration of the lining of the rod. Damage to the rods occurred, starting at 3.5 MPa, 3.1 MPa, 4.1 MPa and 5.5 MPa for the 100-ms, 10-ms, 1-ms and 100-micros sonications, respectively. The formation of large gas bubbles was observed in the blood vessels of the fish at threshold values of 3.8 MPa, 3.8 MPa and 5.3 MPa, for the 100-ms, 10-ms and 1-ms sonications, respectively. Neither gas bubble formation nor hemorrhaging was observed during 100-micros sonications. Bubble formation was always accompanied by an increase of damage to the rods at the area surrounding the bubble. At 1.091 MHz, petechial hemorrhage thresholds were observed at 4.1 MPa, 4.1 MPa and 6.1 MPa, respectively, for the three pulse durations. The thresholds for damage were the lowest for the 0.747-MHz sonications: they were 2.6 MPa for damage to the rods, 3.7 MPa for gas bubble formation and 2.4 MPa for hemorrhaging. PMID:14962610

  14. Underground focusing spotlight synthetic aperture radar for tunnel detection applications

    Microsoft Academic Search

    Jose A. Martinez-Lorenzo; Carey Rappaport

    2009-01-01

    This work studies the concept of a underground focusing plane-based synthetic aperture radar (UF-SL-SAR) by analyzing two different scenarios. The first scenario is a sandy, non-dispersive, homogeneous and rough soil. In this case successful underground focusing can be performed and the scattered field produced by the tunnel just above the rough surface dominates that of by the rough ground surface

  15. Metal array fabrication based on ultrasound-induced self-assembly of metalated dipeptides.

    PubMed

    Isozaki, Katsuhiro; Haga, Yusuke; Ogata, Kazuki; Naota, Takeshi; Takaya, Hikaru

    2013-12-01

    Pd- and Pt-bound bis-metalated peptides were synthesised by the condensation of Pd- or Pt-aldimine-complex-bound glutamic acids to afford the four possible metal isomers of bis-Pd and bis-Pt-homometalated dipeptides and PdPt- and PtPd-heterometalated dipeptides without metal disproportionation. Ultrasound-induced self-assembly of these bis-metalated peptides proceeded effectively to afford supramolecular gels that displayed well-ordered metal arrays. The formation of parallel ?-sheet type aggregates through interpeptide amide-amide hydrogen bonding was confirmed by IR, scanning electron microscopy (SEM), and synchrotron X-ray diffraction analyses (WAXS and SAXS). The mechanism of the ultrasound-induced self-assembly of the metalated dipeptides was elucidated via kinetic and association experiments by (1)H NMR, in which ultrasound-triggered dissociation of intramolecular hydrogen bonds between the chloride ligands of the Pd- and Pt-complexes and amides initially occurred. This was followed by the formation of intermolecular amide-amide hydrogen bonds, which afforded the corresponding oligomeric peptide self-assembly as the nucleus for supramolecular aggregation. The observed first-order relationship of the gelation rate versus the sonication frequency suggested that the microcavitation generated under sonication conditions acted as a crucial trigger and provided a reaction field for efficient self-assembly. PMID:23963158

  16. JAFFA: High sensitivity transcriptome-focused fusion gene detection.

    PubMed

    Davidson, Nadia M; Majewski, Ian J; Oshlack, Alicia

    2015-01-01

    Genomic instability is a hallmark of cancer and, as such, structural alterations and fusion genes are common events in the cancer landscape. RNA sequencing (RNA-Seq) is a powerful method for profiling cancers, but current methods for identifying fusion genes are optimised for short reads. JAFFA (https://github.com/Oshlack/JAFFA/wiki) is a sensitive fusion detection method that outperforms other methods with reads of 100 bp or greater. JAFFA compares a cancer transcriptome to the reference transcriptome, rather than the genome, where the cancer transcriptome is inferred using long reads directly or by de novo assembling short reads. PMID:26019724

  17. A fast silver staining method for protein detection after isoelectric focusing in agarose gels.

    PubMed

    Lasne, F; Benzerara, O; Lasne, Y

    1983-07-15

    A sensitive staining method was developed for detecting proteins in agarose gels after isoelectric focusing. Its sensitivity is about 20 times that of the Coomassie blue R-250 staining technique, and the time required is only 10 min. PMID:6194715

  18. IMAGE MATCHING ERROR DETECTION WITH FOCUS ON MATCHING OF SAR AND OPTICAL IMAGES

    E-print Network

    Schindler, Konrad

    IMAGE MATCHING ERROR DETECTION WITH FOCUS ON MATCHING OF SAR AND OPTICAL IMAGES Soukal Peter, Optical, SAR, Matching, Least Squares Matching, Matching Quality Characterisation, Matching Error Detection ABSTRACT: In this paper, we present matching of multitemporal optical and SAR (Synthetic Aperture

  19. A Detection Theoretic Approach to Digital Fingerprinting With Focused Receivers Under Uniform Linear Averaging Gaussian Attacks

    Microsoft Academic Search

    Ozgur Dalkilic; Ersen Ekrem; Suphi Eray Varlik; Mehmet Kivanç Mihçak

    2010-01-01

    We consider the digital fingerprinting problem where colluders apply uniform linear averaging followed by AWGN. For each user, the receiver computes the correlation between the attacked signal and that user's fingerprint, and performs thresholding (focused detection). We model the finger- printing problem as a multi-user communications problem and develop a detection theoretic framework. Assuming independent colluders, we derive generic exact

  20. Ultrasound-induced heart rate decrease: role of the vagus nerve.

    PubMed

    Coiado, Olivia; Buiochi, Elaine; O'Brien, William

    2015-02-01

    The goal of this study is to investigate the role of the vagus nerve (VN) in the ultrasound (US)-induced negative chronotropic effect (deceased heart rate). One of the functions of the VN is to mediate lowering of the heart rate. A previous study showed a decrease of ~20% in the heart rate but the mechanism of the effect was not investigated. Sprague Dawley rats (n = 20) were exposed transthoracically to ultrasonic pulses at an approximate duty factor of 1% with sequentially 2.0, 2.5, and 3.0 MPa peak rarefactional pressure amplitudes (PRPAs). The ultrasonic exposure parameters herein were chosen to match those of the previous study to have confidence that an ultrasound-induced negative chronotropic effect would occur. For each of the three PRPA sequences, the pulse repetition frequency (PRF) started slightly greater than the rat's heart rate and then was decreased sequentially in 1-Hz steps every 10 s (i.e., 6, 5, and 4 Hz for a total duration of 30 s). The experiments were organized in a standard (2 × 2) factorial design with VN (cut versus intact) as one factor and US (on versus off) as another factor. VN (intact/cut) and US (on/off) groups were divided into four groups each consisting of 5 animals: 1) VN intact-US off, 2) VN intact-US on, 3) VN cut-US off, and 4) VN cut-US on. Two-way analysis of variance for repeated measures was used to compare heart rate, cardiac output, systolic volume, ejection fraction, end-diastolic volume, end-systolic volume, respiratory rate, and arterial pressure before and after ultrasound stimulation. In this study, the heart rate decreased ~4% for the non-vagotomy and vagotomy groups. The ultrasound effect was significant for heart rate (p = 0.02) and cardiac output (p = 0.005) at 3 min post US exposure; the vagotomy effect was not significant. For heart rate, the Bonferroni test showed no differences between the four groups. The vagotomy group showed similar ultrasound-induced cardiac effects compared with the non-vagotomy group, suggesting that the vagus nerve is not influenced by the ultrasound exposure procedures. The US application caused a negative chronotropic effect of the rat heart without affecting the hemodynamic conditions. The results at this point are suggestive for an alternative cardiac pacing capability. PMID:25643082

  1. Comparison of signal and gap-detection thresholds for focused and broad cochlear implant electrode configurations.

    PubMed

    Bierer, Julie Arenberg; Deeks, John M; Billig, Alexander J; Carlyon, Robert P

    2015-04-01

    Cochlear implant (CI) users usually exhibit marked across-electrode differences in detection thresholds with "focused" modes of stimulation, such as partial-tripolar (pTP) mode. This may reflect differences either in local neural survival or in the distance of the electrodes from the modiolus. To shed light on these two explanations, we compared stimulus-detection thresholds and gap-detection thresholds (GDTs) at comfortably loud levels for at least four electrodes in each of ten Advanced Bionics CI users, using 1031-pps pulse trains. The electrodes selected for each user had a wide range of stimulus-detection thresholds in pTP mode. We also measured across-electrode variations in both stimulus-detection and gap-detection tasks in monopolar (MP) mode. Both stimulus-detection and gap-detection thresholds correlated across modes. However, there was no significant correlation between stimulus-detection and gap-detection thresholds in either mode. Hence, gap-detection thresholds likely tap a source of across-electrode variation additional to, or different from, that revealed by stimulus-detection thresholds. Stimulus-detection thresholds were significantly lower for apical than for basal electrodes in both modes; this was only true for gap detection in pTP mode. Finally, although the across-electrode standard deviation in stimulus-detection thresholds was greater in pTP than in MP mode, the reliability of these differences--assessed by dividing the across-electrode standard deviation by the standard deviation across adaptive runs for each electrode--was similar for the two modes; this metric was also similar across modes for gap detection. Hence across-electrode differences can be revealed using clinically available MP stimulation, with a reliability comparable to that observed with focused stimulation. PMID:25644786

  2. Histological and Ultrastructural Effects of Ultrasound-induced Cavitation on Human Skin Adipose Tissue

    PubMed Central

    Li, Alessandro Quattrini; Freschi, Giancarlo; Russo, Giulia Lo

    2013-01-01

    Background: In aesthetic medicine, the most promising techniques for noninvasive body sculpturing purposes are based on ultrasound-induced fat cavitation. Liporeductive ultrasound devices afford clinically relevant subcutaneous fat pad reduction without significant adverse reactions. This study aims at evaluating the histological and ultrastructural changes induced by ultrasound cavitation on the different cell components of human skin. Methods: Control and ultrasound-treated ex vivo abdominal full-thickness skin samples and skin biopsies from patients pretreated with or without ultrasound cavitation were studied histologically, morphometrically, and ultrastructurally to evaluate possible changes in adipocyte size and morphology. Adipocyte apoptosis and triglyceride release were also assayed. Clinical evaluation of the effects of 4 weekly ultrasound vs sham treatments was performed by plicometry. Results: Compared with the sham-treated control samples, ultrasound cavitation induced a statistically significant reduction in the size of the adipocytes (P < 0.001), the appearance of micropores and triglyceride leakage and release in the conditioned medium (P < 0.05 at 15 min), or adipose tissue interstitium, without appreciable changes in microvascular, stromal, and epidermal components and in the number of apoptotic adipocytes. Clinically, the ultrasound treatment caused a significant reduction of abdominal fat. Conclusions: This study further strengthens the current notion that noninvasive transcutaneous ultrasound cavitation is a promising and safe technology for localized reduction of fat and provides experimental evidence for its specific mechanism of action on the adipocytes. PMID:25289235

  3. Physical Limitations on Detecting Tunnels using Underground Focusing Spotlight Synthetic Aperture Radar

    Microsoft Academic Search

    Carey M. Rappaport; Jose Angel Martinez Lorenzo

    2009-01-01

    This work studies the concept of Underground Focusing Spotlight Synthetic Aperture Radar (UF-SL-SAR) systems for tunnel detection applications. A general formulation for generating UF-SL-SAR imaging in realistic, randomly rough ground is developed by focusing in space and frequency at subsurface points by considering rays refraction at the nominal ground surface. Imaging results are presented for two soil scenarios: dry sand

  4. Feasibility of tunnel detection under rough ground surfaces using Underground Focusing Spotlight Synthetic Aperture Radar

    Microsoft Academic Search

    Fernando Quivira; Kristen Fassbender; Jose A. Martinez-Lorenzo; Carey M. Rappaport

    2010-01-01

    Detecting and imaging the presence of illicit tunnels in any given volume of soil is occasionally possible because the air that fills them is materially quite different from anything else underground. The Underground Focusing Spotlight Synthetic Aperture Radar (UF-SL-SAR) concept has been suggested for sub-surface tunnel detection due to its ability to scan large areas of terrain in a short

  5. Experimental verification for detection of damage of sensor-arrayed truss domes using a focusing strategy

    NASA Astrophysics Data System (ADS)

    Hamamoto, T.

    2005-06-01

    A damage detection scheme using a focusing strategy, developed for the purpose of maintaining structural integrity of truss domes during their service life, that estimates the location and extent of damage on the basis of vibration monitoring and system identification is presented. The main idea of the focusing strategy is to reduce the number of unknown physical parameters as much as possible by shifting from global to local damage detection gradually. The scheme is divided into three stages: global, intermediate and local damage detection. In the global damage detection, the central concern is whether the damage occurs in the superstructure or substructure. In the intermediate damage detection, possible damaged regions are located in the superstructure. In the local damage detection, damaged members or joints are located in the damaged regions. Finally, the extent of member, joint or support damage is quantified in terms of member stiffness reduction ratios. Depending on the damage detection levels, different probing forces are used and different damage indices are defined. To verify the overall damage detection scheme, a series of shaking table, vibration generator and impact hammer tests have been carried out for a small-scale experimental model. On the basis of the damage identification results, the effectiveness and limitations of the proposed scheme are discussed.

  6. DETECTION AND FOCUSED IMAGING OF MOVING OBJECTS EVALUATING A SEQUENCE OF SINGLE--LOOK SAR IMAGES *

    E-print Network

    DETECTION AND FOCUSED IMAGING OF MOVING OBJECTS EVALUATING A SEQUENCE OF SINGLE--LOOK SAR IMAGES: kirscht@tnt.uni--hannover.de ABSTRACT In multilook synthetic aperture radar (SAR) images moving objects of single--look SAR images. These images are processed using different look center frequencies and therefore

  7. Controlled trial of serum isoelectric focusing in the detection of the cystic fibrosis gene

    Microsoft Academic Search

    David J. H. Brock; Caroline Hayward; Maurice Super

    1982-01-01

    Three independent observers assessed the discriminating power of serum isoelectric focusing in detecting the presence of the cystic fibrosis gene. On the basis of average scores, four out of 23 cystic fibrosis patients, six out of 22 heterozygotes, and three out of 16 controls were misclassified. However, the mean scores for the cystic fibrosis and heterozygote groups were significantly different

  8. A Distance Measure for Attention Focusing and Anomaly Detection in Systems Monitoring

    NASA Technical Reports Server (NTRS)

    Doyle, R.

    1994-01-01

    Any attempt to introduce automation into the monitoring of complex physical systems must start from a robust anomaly detection capability. This task is far from straightforward, for a single definition of what constitutes an anomaly is difficult to come by. In addition, to make the monitoring process efficient, and to avoid the potential for information overload on human operators, attention focusing must also be addressed. When an anomaly occurs, more often than not several sensors are affected, and the partially redundant information they provide can be confusing, particularly in a crisis situation where a response is needed quickly. Previous results on extending traditional anomaly detection techniques are summarized. The focus of this paper is a new technique for attention focusing.

  9. Diffraction analysis and evaluation of several focus- and track-error detection schemes for magneto-optical disk systems

    NASA Technical Reports Server (NTRS)

    Bernacki, Bruce E.; Mansuripur, M.

    1992-01-01

    A commonly used tracking method on pre-grooved magneto-optical (MO) media is the push-pull technique, and the astigmatic method is a popular focus-error detection approach. These two methods are analyzed using DIFFRACT, a general-purpose scalar diffraction modeling program, to observe the effects on the error signals due to focusing lens misalignment, Seidel aberrations, and optical crosstalk (feedthrough) between the focusing and tracking servos. Using the results of the astigmatic/push-pull system as a basis for comparison, a novel focus/track-error detection technique that utilizes a ring toric lens is evaluated as well as the obscuration method (focus error detection only).

  10. Defect detection around rebars in concrete using focused ultrasound and reverse time migration.

    PubMed

    Beniwal, Surendra; Ganguli, Abhijit

    2015-09-01

    Experimental and numerical investigations have been performed to assess the feasibility of damage detection around rebars in concrete using focused ultrasound and a Reverse Time Migration (RTM) based subsurface imaging algorithm. Since concrete is heterogeneous, an unfocused ultrasonic field will be randomly scattered by the aggregates, thereby masking information about damage(s). A focused ultrasonic field, on the other hand, increases the possibility of detection of an anomaly due to enhanced amplitude of the incident field in the focal region. Further, the RTM based reconstruction using scattered focused field data is capable of creating clear images of the inspected region of interest. Since scattering of a focused field by a damaged rebar differs qualitatively from that of an undamaged rebar, distinct images of damaged and undamaged situations are obtained in the RTM generated images. This is demonstrated with both numerical and experimental investigations. The total scattered field, acquired on the surface of the concrete medium, is used as input for the RTM algorithm to generate the subsurface image that helps to identify the damage. The proposed technique, therefore, has some advantage since knowledge about the undamaged scenario for the concrete medium is not necessary to assess its integrity. PMID:26032923

  11. Detection of sub-horizontal flaws in concrete using the synthetic aperture focusing technique

    NASA Astrophysics Data System (ADS)

    Hosseini, Zahra

    Concrete deteriorates over time due to environmental changes and/or poor construction processes which can eventually lead to partial or total failure of a structure. Deterioration in concrete manifests itself in different forms such as: freeze and thaw, chemical attack, surface and internal flaws. Concrete and shotcrete linings are widely used as support systems in underground excavations. Surprisingly, a fragmented, damaged shotcrete support system can actually create a less stable environment than the unsupported rock mass. Detection of internal flaws remains a difficult task as they are not always observable on the surface. Yet, the potential to expand and cause damage to the structure is omnipresent. The focus of this work is to locate and characterize two main and common features in concrete structures, (1) sub-horizontal cracks; (2) rock-concrete interfaces. Traditionally, this has been difficult to detect by currently available NDT methods. To obtain high resolution images of cracks in concrete, an extension of the ultrasonic nondestructive technique known as Synthetic Aperture Focusing Technique (SAFT) has been used. However, in order to achieve our research objective, we developed a modified SAFT code in this work. The results of this study demonstrate that the resolving power of our modified 3D SAFT algorithm can provide an accurate profile of both a rock-concrete interface and/or cracks with angles varying from 5 to 15 degrees within concrete slabs having thicknesses of up to twenty centimetres.

  12. Capillary isoelectric focusing of proteins and microorganisms in dynamically modified fused silica with UV detection.

    PubMed

    Horká, Marie; R?zicka, Filip; Horký, Jaroslav; Holá, Veronika; Slais, Karel

    2006-09-01

    We suggest a method for the reproducible and efficient capillary isoelectric focusing of proteins and microorganisms in the pH gradient 3-10. The method involves the segmental injection of the simple ampholytes, the solution of the selected electrolytes, and the sample mixture of bioanalytes and carrier ampholytes to the fused silica capillaries dynamically modified by poly(ethylene glycol), PEG 4000, which is added to the catholyte, the anolyte and injected solutions. In order to receive the reproducible results, the capillaries were rinsed by the mixture of acetone/ethanol between analyses. For the tracing of the pH gradients the low-molecular-mass pI markers were used. The simple proteins and the mixed cultures of microorganisms, Saccharomyces cerevisiae CCM 8191, Escherichia coli CCM 3954, Candida albicans CCM 8180, Candida parapsilosis, Candida krusei, Staphylococcus aureus, Streptococcus agalactiae CCM 6187, Enterococcus faecalis CCM 4224, Staphylococcus epidermidis CCM 4418 and Stenotrophomonas maltophilia, were focused and separated by the method suggested. The minimum detectable number of microbial cells was 5x10(2) to 1x10(3) with on-column UV detection at 280 nm. PMID:16765111

  13. Improved digital SEM of cancellous bone: scanning direction of detection, through focus for in-focus and sample orientation.

    PubMed

    Boyde, Alan

    2003-02-01

    Three-dimensional (3D) study of cancellous bone tissue organization is necessary to understand how modelling and remodelling processes regulate bone structure and connectivity. It requires imaging methods that have both sufficient resolution power and width and depth of field. Since clinical imaging methods fall far short of the first requirement, we can only study prepared tissue in isolation from the body. Scanning electron microscopy (SEM) of macerated plane parallel slices is the most productive method, but we meet special technical problems in imaging porous bone because samples need to be relatively thick to maintain both continuity and context. Problems due to charging under the electron beam can be controlled by imaging with only high-energy backscattered electrons (BSE). This gives an important additional benefit that the direction of apparent illumination can be manipulated by positioning the detector, and multiple detector positions can be employed strategically to generate images in which colour is used to help in coding surface morphology. However, we next confront the difficulty of the limited depth of field. This can be improved by taking series of images, moving the sample along the electron optic axis, and combining these to generate a single extended-focus image. SEM imaging geometry gives a change in magnification with change of working distance, and it is shown that this must be corrected for each image of the through-focus sequence. Colour coding the lighting direction and increasing the depth of field are approaches that can be combined, and are well matched to the possibilities offered by communication by digital data projection. Finally, the latter means also offer another powerful technique for 3D representation through the display of through tilt image sequences. The novel routines considered here are generally applicable to all classes of microanatomical SEM sample. PMID:12647868

  14. Optical Generation and Detection of High-Frequency Focused Ultrasound and Associated Nonlinear Effects

    NASA Astrophysics Data System (ADS)

    Baac, Hyoung Won

    In this thesis, optical generation and detection of high-frequency ultrasound are presented. On the generation side, high-efficiency optical transmitters have been devised and developed which can generate high-frequency and high-amplitude pressure. Conventional optoacoustic transmitters have suffered from poor optoacoustic energy conversion efficiency (10-7˜10-8). Therefore, pressure amplitudes were usually weak for long-range imaging (several cm) and too weak to induce any therapeutic effects. Here, far beyond such traditional regime, therapeutic pressure amplitudes of tens of MPa were achieved optoacoustically. First, high-efficiency optoacoustic sources were developed in planar geometries by using carbon nanotubepolymer composites. The planar transmitters could generate 18-fold stronger pressure than thin metallic films used as references, together with providing broadband and high-frequency spectra over 120 MHz. Then, the thin-film transmitters were formed on concave substrates to generate and simultaneously focus the ultrasound. Unprecedented optoacoustic pressure was achieved at lens focus: >50 MPa in positive and >20 MPa in negative peaks. These amplitudes were sufficient to induce strong shock waves and acoustic cavitation. Due to the high-frequency operation, such therapeutic pressure and the induced effects were tightly localized onto focal widths of 75microm in lateral and 400 microm in axial directions, which are an order of magnitude smaller than those of traditional piezoelectric transducers. The shock waves and the cavitation effects were investigated in various ways. High focal gains and short distances for shock formation were suggested as main features. The optoacoustic approach is expected to open numerous opportunities for a broad range of biomedical applications demanding high-accuracy treatment with minimal damage volumes around focal zones. For optical detection of ultrasound, optical microring resonators have been used due to their broadband frequency responses (˜100 MHz) and high sensitivity. However, their spatial responses due to the particular ring shape have not been investigated especially for high-frequency ranges. Here, the microring responses were characterized in this regime. As a final subject, the microrings were used to detect focused ultrasound and realize novel optoacoustic 4f imaging systems which have capabilities of fast 3-D imaging without requiring mathematical reconstruction steps. High-resolution performances were demonstrated by resolving polymer microspheres of 100-microm diameter.

  15. Detection and differentiation of microbial siderophores by isoelectric focusing and chrome azurol S overlay.

    PubMed

    Koedam, N; Wittouck, E; Gaballa, A; Gillis, A; Höfte, M; Cornelis, P

    1994-10-01

    Siderophores are microbial, low molecular weight iron-chelating compounds. Fluorescent Pseudomonads produce different, strain-specific fluorescent siderophores (pyoverdines) as well as non-fluorescent siderophores in response to low iron conditions. We present an isoelectric focusing method applicable to unpurified as well as to purified pyoverdine samples where the fluorescent siderophores are visualized under UV illumination. Siderophores from different Pseudomonas sp., amongst which are P. aeruginosa, P. fluorescens and P. putida, including egg yolk, rhizospheric and clinical isolates as well as some derived Tn5 mutants were separated by this technique. Different patterns could be observed for strains known to produce different siderophores. The application of the chrome azurol S assay as a gel overlay further allows immediate detection of non-fluorescent siderophores or possibly degradation products with residual siderophore activity. The method was also applied to other microbial siderophores such as deferrioxamine B. PMID:7812113

  16. Along-Track Focusing of Airborne Radar Sounding Data From West Antarctica for Improving Basal Reflection Analysis and Layer Detection

    Microsoft Academic Search

    Matthew E. Peters; Donald D. Blankenship; Sasha P. Carter; Scott D. Kempf; Duncan A. Young; John W. Holt

    2007-01-01

    This paper presents focused synthetic aperture radar (SAR) processing of airborne radar sounding data acquired with the High-Capability Radar Sounder system at 60 MHz. The motivation is to improve basal reflection analysis for water detection and to improve layer detection and tracking. The processing and reflection analyses are applied to data from Kamb Ice Stream, West Antarctica. The SAR processor

  17. SEIS/INSIGHT and Mars seismology: Development status and focus on the Impact detection

    NASA Astrophysics Data System (ADS)

    Lognonne, Philippe; Banerdt, William; Pike, Tom; Giardini, Domenico; Christensen, Ulli; Banfield, Don; Mimoun, David; Laudet, Philippe; de Raucourt, Sebastien; Bierwirth, Marco; Zweifel, Peter; Calcutt, Simon; Hurst, Ken; Bruce, Carl

    2014-05-01

    The INSIGHT NASA Discovery mission will deploy in September 2016 a 3 axis Very Broad band seismometer and a 3 axis SP seismometer, as well as other instruments enabling the installation of a complete geophysical observatory recording seismic, heat flow, magnetic and geodetic signals, in addition to atmospheric wind, pressure and temperature. We first present the science goals status of the SEIS experiment and its development status. The SEIS sensor assembly, which contains both the VBB and SP seismometer, will be deployed on the Martian ground by a robotic arm from a Phoenix-type lander platform and protected by a wind and thermal shield. The wind and thermal shield, a vacuum sphere for VBBs and a passive compensation system will achieve a very high protection of the seismometers against temperature and pressure variations, allowing the sensor to operate in the rough Martian thermal environment while reaching a detection threshold below 10^(-9) m/s/s Hz^(-1/2) in the VBB bandwidth and 10^(-8) m/s/s Hz^(-1/2) for the SP. A levelling system will allow the VBB to operate, while providing to both seismometer the best possible mechanical coupling with the ground motion. The SEIS instrument will be provided by CNES, which will coordinate a wide set of international contributors from the Institut de Physique du Globe de Paris, the Imperial College from London and the Open University, the Max-Planck Insitute of Lindau, the École polytechnique fédérale de Zurich (ETHZ), the Jet Propulsion Laboratory and the Institut de l'Aéronautique et de l'Espace from Toulouse. We then illustrate the science goals by a focus on the capability of INSIGHT to detect either seismic or acoustic signals from impacts, with both the seismometers and the pressure sensor, and present both amplitude and occurrence expectation, based on comparative modeling between Mars, Earth and the Moon.

  18. Detection of thyroglobulin in antithyroglobulin antibody-positive sera by isoelectric focusing.

    PubMed

    Malvoisin, Etienne; Makhloufi, Djamila; Livrozet, Jean-Michel

    2015-07-20

    Circulating antibodies have the potential to interfere with the measurement of thyroglobulin (Tg) in sera of patients. Here, we determined Tg concentration by isoelectric focusing (IEF) on agarose gel using for detection a rabbit antiserum to human Tg termed FLX. Tg was determined in sera of thyroid patients and HIV-infected patients under antiviral therapy. We showed that Tg IEF was not affected by the presence of anti-Tg antibodies (TgAb). Tg concentrations measured by IEF in TgAb-negative sera were in most of the cases, similar to those obtained by IRMA (immunoradiometric assay). However, in 5 of the 96 thyroid patients, and none of the 46 healthy subjects, Tg was undetectable by antiserum FLX and measurable by IRMA. In HIV-infected patients (64 men and 60 women), Tg was not recognized by FLX in 23 men and 9 women and this was related to abnormal CD4. We hypothesize that the decreased binding of FLX to Tg may be the result of conformational change on the Tg molecule, a phenomenon apparently related to immunodeficiency in HIV-infected patients. For thyroid patients, Tg IEF may be very useful for the interpretation of results when Tg measurements by IRMA and automated immunoassays are affected by interferences. PMID:25998693

  19. Capillary isoelectric focusing and fluorometric detection of proteins and microorganisms dynamically modified by poly(ethylene glycol) pyrenebutanoate.

    PubMed

    Horka, Marie; Ruzicka, Filip; Horký, Jaroslav; Holá, Veronika; Slais, Karel

    2006-12-15

    The nonionogenic pyrene-based tenside, poly(ethylene glycol) pyrenebutanoate, was prepared and applied in capillary isoelectric focusing with fluorometric detection. This dye was used here as a buffer additive in capillary isoelectric focusing for a dynamic modification of the sample of proteins and microorganisms. The values of the isoelectric points of the labeled bioanalytes were calculated with use of the fluorescent pI markers and were found comparable with pI of the native compounds. The mixed cultures of proteins and microorganisms, Escherichia coli CCM 3954, Staphylococcus epidermidis CCM 4418, Proteus vulgaris, Enterococcus faecalis CCM 4224, and Stenotrophomonas maltophilia, the strains of the yeast cells, Candida albicans CCM 8180, Candida krusei, Candida parapsilosis, Candida glabrata, Candida tropicalis, and Saccharomyces cerevisiae were reproducibly focused and separated by the suggested technique. Using UV excitation for the on-column fluorometric detection, the minimum detectable amount was down to 10 cells injected on the separation capillary. PMID:17165837

  20. Focused Screening and Treatment (FSAT): A PCR-Based Strategy to Detect Malaria Parasite Carriers and Contain

    E-print Network

    Paris-Sud XI, Université de

    Focused Screening and Treatment (FSAT): A PCR-Based Strategy to Detect Malaria Parasite Carriers'Immunologie Mole´culaire des Parasites, Institut Pasteur, Paris, France, 8 Malaria Centre, London School of Hygiene malaria parasites in Pailin province, along the border between Thailand and Cambodia, have become

  1. Sol-gel column technology for capillary isoelectric focusing of microorganisms and biopolymers with UV or fluorometric detection.

    PubMed

    Horká, Marie; Planeta, Josef; R?zicka, Filip; Slais, Karel

    2003-05-01

    The sol-gel surface modification is used for capillary isoelectric focusing of microorganisms and biopolymers. The coating strongly decreases the electroosmotic flow so that it enables the use of the short capillaries down to 100 mm in the separation length. The examples of capillary isoelectric focusing of the low-molecular-mass pI markers and mixed cultures of microbial populations of Escherichia coli, Candida albicans, Staphylococcus epidermidis, and Enteroccocus faecalis with UV detection are shown. It is possible to quantify bacterial cells according to their peak areas; the minimum detectable number of microbial cells was 5 x 10(2)-1 x 10(3). The compatibility of sol-gel capillaries with sensitive fluorometric detection of fluorescent pI markers together with fluorescein labeled proteins is demonstrated. PMID:12731023

  2. Learning to Detect Conversation Focus of Threaded Discussions Donghui Feng Erin Shaw Jihie Kim Eduard Hovy

    E-print Network

    Kim, Jihie

    link generation functions. It is the first quantitative study to analyze hu- man conversation focus is popular in virtual cyber communities and has applications in areas such as customer support, community

  3. Buried target detection based on time reversal focusing with a probe source

    Microsoft Academic Search

    Jianlong Li; Xiang Pan; Hangfang Zhao

    2009-01-01

    Buried target detection under the background of strong reverberation in shallow water is a complicated problem. As the target is buried, the echo of the active sonar is very weak and the echo-to-reverberation ratio (ERR) is quite low. In the paper, the technique of time reversal (TR) with a probe source is discussed to detect a buried target. By TR

  4. Optimization of the Ultrasound-Induced Blood-Brain Barrier Opening

    PubMed Central

    Konofagou, Elisa E.

    2012-01-01

    Current treatments of neurological and neurodegenerative diseases are limited due to the lack of a truly non-invasive, transient, and regionally selective brain drug delivery method. The brain is particularly difficult to deliver drugs to because of the blood-brain barrier (BBB). The impermeability of the BBB is due to the tight junctions connecting adjacent endothelial cells and highly regulatory transport systems of the endothelial cell membranes. The main function of the BBB is ion and volume regulation to ensure conditions necessary for proper synaptic and axonal signaling. However, the same permeability properties that keep the brain healthy also constitute the cause of the tremendous obstacles posed in its pharmacological treatment. The BBB prevents most neurologically active drugs from entering the brain and, as a result, has been isolated as the rate-limiting factor in brain drug delivery. Until a solution to the trans-BBB delivery problem is found, treatments of neurological diseases will remain impeded. Over the past decade, methods that combine Focused Ultrasound (FUS) and microbubbles have been shown to offer the unique capability of noninvasively, locally and transiently open the BBB so as to treat central nervous system (CNS) diseases. Four of the main challenges that have been taken on by our group and discussed in this paper are: 1) assess its safety profile, 2) unveil the mechanism by which the BBB opens and closes, 3) control and predict the opened BBB properties and duration of the opening and 4) assess its premise in brain drug delivery. All these challenges will be discussed, findings in both small (mice) and large (non-human primates) animals are shown and finally the clinical potential for this technique is shown. PMID:23382778

  5. Ultrasonic imaging, particle detection, and V(z) measurements in molten zinc using focused clad buffer rods

    NASA Astrophysics Data System (ADS)

    Ihara, I.; Jen, C.-K.; Ramos França, D.

    2000-09-01

    Ultrasonic imaging, particle detection, and V(z) measurements have been performed using focused clad buffer rods in molten zinc at temperature more than 600 °C. The focused ultrasonic waves are generated by a spherical or cylindrical acoustic lens which is fabricated at the end of the clad buffer rod. In order to evaluate its focusing ability, several experiments are carried out at 10 MHz in a pulse-echo mode. The lateral resolution at the focus of the spherical acoustic lens in molten zinc is quantitatively examined and compared with that in water using a thin stainless wire with a diameter of 380 ?m. High resolution ultrasonic imaging is carried out by the common C-scan technique. The signal-to-noise ratio of the reflected signals from the flat sample surface at the focus is better than 35 dB. Ultrasonic images are obtained from the amplitude and time delay variations of the reflected signals. An attempt has also been made to detect particles suspended in molten zinc. Backscattered signals from particles are clearly visible at the focal region of the lens. For quantitative materials evaluation, V(z) curve measurements are performed using both spherical and cylindrical surface lenses and the leaky surface acoustic wave velocity of a ceramic (SiC) plate immersed in molten zinc is successfully determined.

  6. Ultrasound-induced DNA damage and signal transductions indicated by gammaH2AX

    NASA Astrophysics Data System (ADS)

    Furusawa, Yukihiro; Fujiwara, Yoshisada; Zhao, Qing-Li; Hassan, Mariame Ali; Ogawa, Ryohei; Tabuchi, Yoshiaki; Takasaki, Ichiro; Takahashi, Akihisa; Ohnishi, Takeo; Kondo, Takashi

    2011-09-01

    Ultrasound (US) has been shown to induce cancer cell death via different forms including apoptosis. Here, we report the potential of low-intensity pulsed US (LIPUS) to induce genomic DNA damage and subsequent DNA damage response. Using the ionizing radiation-induced DNA double-strand breaks (DSBs) as the positive control, we were able to observe the induction of DSBs (as neutral comet tails) and the subsequent formation of gammaH2AX-positive foci (by immunofluorescence detection) in human leukemia cells following exposure to LIPUS. The LIPUS-induced DNA damage arose most likely from the mechanical, but not sonochemical, effect of cavitation, based on our observation that the suppression of inertial cavitation abrogated the gammH2AX foci formation, whereas scavenging of free radical formation (e.g., hydroxyl radical) had no protective effect on it. Treatment with the specific kinase inhibitor of ATM or DNA-PKcs, which can phosphorylate H2AX Ser139, revealed that US-induced gammaH2AX was inhibited more effectively by the DNA-PK inhibitor than ATM kinase inhibitor. Notably, these inhibitor effects were opposite to those with radiation-induced gammH2AX. In conclusion, we report, for the first time that US can induce DNA damage and the DNA damage response as indicated by gammaH2AX was triggered by the cavitational mechanical effects. Thus, it is expected that the data shown here may provide a better understanding of the cellular responses to US.

  7. Modelling ultrasound-induced mild hyperthermia of hyperplasia in vascular grafts

    PubMed Central

    2011-01-01

    Background Expanded polytetrafluoroethylene (ePTFE) vascular grafts frequently develop occlusive neointimal hyperplasia as a result of myofibroblast over-growth, leading to graft failure. ePTFE exhibits higher ultrasound attenuation than native soft tissues. We modelled the selective absorption of ultrasound by ePTFE, and explored the feasibility of preventing hyperplasia in ePTFE grafts by ultrasound heating. Specifically, we simulated the temperature profiles of implanted grafts and nearby soft tissues and blood under ultrasound exposure. The goal was to determine whether ultrasound exposure of an ePTFE graft can generate temperatures sufficient to prevent cell growth on the graft without damaging nearby soft tissues and blood. Methods Ultrasound beams from two transducers (1.5 and 3.2 MHz) were simulated in two graft/tissue models, with and without an intra-graft cellular layer mimicking hyperplasia, using the finite-difference time-domain (FDTD) method. The resulting power deposition patterns were used as a heat source for the Pennes bioheat equation in a COMSOL® Multiphysics heat transfer model. 50°C is known to cause cell death and therefore the transducer powers were adjusted to produce a 13°C temperature rise from 37°C in the ePTFE. Results Simulations showed that both the frequency of the transducers and the presence of hyperplasia significantly affect the power deposition patterns and subsequent temperature profiles on the grafts and nearby tissues. While neither transducer significantly raised the temperature of the blood, the 1.5-MHz transducer was less focused and heated larger volumes of the graft and nearby soft tissues than the 3.2-MHz transducer. The presence of hyperplasia had little effect on the blood's temperature, but further increased the temperature of the graft and nearby soft tissues in response to either transducer. Skin cooling and blood flow play a significant role in preventing overheating of the native tissues. Conclusions Modelling shows that ultrasound can selectively heat ePTFE grafts and produce temperatures that cause cell death on the graft. The temperature increase in blood is negligible and that in the adjacent soft tissues may be minimized by skin cooling and using appropriate transducers. Therefore, ultrasound heating may have the potential to reduce neointimal hyperplasia and failure of ePTFE vascular grafts. PMID:22054016

  8. Ultrasound-induced thermal therapy of hyperplasia in ringed expanded polytetrafluoroethylene (eptfe) access grafts

    NASA Astrophysics Data System (ADS)

    Query, Michael Earl

    Hemodialysis vascular access, the interface between a dialysis patient and a dialysis machine, is quite literally the lifeblood of a patient's health. Vascular access dysfunction is the leading cause of hospitalization in hemodialysis patients. The occlusive growth of neointimal hyperplasia (NH) in expanded polytetrafluoroethylene (ePTFE) ringed grafts is the primary cause of failure. To further develop a proposed thermal ultrasound treatment to reduce or prevent NH in arteriovenous vascular grafts, the acoustic properties of ePTFE were studied in water and alcohol solutions. Previous reports of ePTFE acoustic properties are critiqued. It was found that the acoustic transmission and attenuation through ePTFE, and therefore the potential for an ultrasound-based therapy for NH, are heavily dependent on the medium in which the graft is immersed, suggesting that the acoustic properties of implanted grafts will change as grafts mature in vivo. The acoustic impedance and attenuation of water-soaked ePTFE were 0.478 +/- 1.43 x 10-2 MRayl and 1.78 +/- 0.111 Np/cm*MHz, respectively, while the acoustic impedance and attenuation of ePTFE in alcohol were 1.49 +/- 0.149 MRayl and 0.77 +/- 1.1 x 10-2 Np/cm*MHz, respectively. The use of focused ultrasound to heat implanted ringed ePTFE grafts was numerically modeled from 1.35- and 1.443-MHz transducers for in vitro geometries. Power deposition and heating, in turn, differed by an order of magnitude between various graft acoustic properties. Graft rings were predicted to be substantial absorbing and scattering features. In vitro phantom models were constructed: one with and one without thermocouples. At 1 W of acoustic power, the maximum temperature rise was 8? C. The thermocouple model containing a water-soaked graft did not experience heating in the far graft wall. The MRTI model confirmed that the graft rings are an absorbing/scattering feature. Heating was not prevented in the presence of water flow through the graft. Water was not heated significantly. Overall, results suggest ultrasound exposure can be used to generate temperature rises corresponding with the potential prevention or inhibition of NH in ringed ePTFE vascular grafts. A hybrid therapeutic/diagnostic transducer design with a therapeutic semi-annular array surrounding a diagnostic linear array is presented. Compared to a solid transducer of the same dimensions, there were only marginal aberrations in the focal plane. Numerical optimization of the element drive configuration indicated that the least distorted focal plane was produced by uniform phase and magnitude at each element.

  9. A Distance Measure for Attention Focusing and Anaomaly Detection in Systems Monitoring

    NASA Technical Reports Server (NTRS)

    Doyle, R. J.

    1994-01-01

    Any attempt to introduce automation into the monitoring of complex physical systems must start from a robust anomaly detection capability. This task is far from straightforward, for a single definition of what constitutes an anomaly is difficult to come by.

  10. Capillary isoelectric focusing--useful tool for detection of the biofilm formation in Staphylococcus epidermidis.

    PubMed

    Ruzicka, Filip; Horka, Marie; Hola, Veronika; Votava, Miroslav

    2007-03-01

    The biofilm formation is an important factor of S. epidermidis virulence. Biofilm-positive strains might be clinically more important than biofilm-negative ones. Unlike biofilm-negative staphylococci, biofilm-positive staphylococci are surrounded with an extracellular polysaccharide substance. The presence of this substance on the surface can affect physico-chemical properties of the bacterial cell, including surface charge. 73 S. epidermidis strains were examined for the presence of ica operon, for the ability to form biofilm by Christensen test tube method and for the production of slime by Congo red agar method. Isoelectric points (pI) of these strains were determined by means of Capillary Isoelectric Focusing. The biofilm negative strains focused near pI value 2.3, while the pI values of the biofilm positive strains were near 2.6. Isoelectric point is a useful criterion for the differentiation between biofilm-positive and biofilm-negative S. epidermidis strains. PMID:17157942

  11. Multimodal Focus Attention and Stress Detection and feedback in an Augmented Driver Simulator

    Microsoft Academic Search

    Alexandre Benoit; Laurent Bonnaud; Alice Caplier; Phillipe Ngo; Lionel Lawson; Daniela G. Trevisan; Vjekoslav Levacic; Céline Mancas; Guillaume Chanel

    2006-01-01

    This paper presents a driver simulator, which takes into account information about the user's state of mind (level of attention, fatigue state, stress state). The user's state of mind analysis is based on video data and biological signals. Facial movements such as eyes blinking, yawning, head rotations… are detected on video data: they are used in order to evaluate the

  12. Detection and differentiation of microbial siderophores by isoelectric focusing and chrome azurol S overlay

    Microsoft Academic Search

    Nico Koedam; Etienne Wittouck; Ahmed Gaballa; Anja Gillis; Monica Höfte; Pierre Cornelis

    1994-01-01

    Siderophores are microbial, low molecular weight iron-chelating compounds. Fluorescent Pseudomonads produce different, strain-specific fluorescent siderophores (pyoverdines) as well as non-fluorescent siderophores in response to low iron conditions. We present an isoelectric focusing method applicable to unpurified as well as to purified pyoverdine samples where the fluorescent siderophores are visualized under UV illumination. Siderophores from different Pseudomonas sp., amongst which are

  13. Capillary isoelectric focusing of proteins and microorganisms in dynamically modified fused silica with UV detection

    Microsoft Academic Search

    Marie Horká; Filip R?ži?ka; Jaroslav Horký; Veronika Holá; Karel Šlais

    2006-01-01

    We suggest a method for the reproducible and efficient capillary isoelectric focusing of proteins and microorganisms in the pH gradient 3–10. The method involves the segmental injection of the simple ampholytes, the solution of the selected electrolytes, and the sample mixture of bioanalytes and carrier ampholytes to the fused silica capillaries dynamically modified by poly(ethylene glycol), PEG 4000, which is

  14. An integrated dielectrophoretic chip for continuous bioparticle filtering, focusing, sorting, trapping, and detecting

    PubMed Central

    Cheng, I-Fang; Chang, Hsien-Chang; Hou, Diana; Chang, Hsueh-Chia

    2007-01-01

    Multi-target pathogen detection using heterogeneous medical samples require continuous filtering, sorting, and trapping of debris, bioparticles, and immunocolloids within a diagnostic chip. We present an integrated AC dielectrophoretic (DEP) microfluidic platform based on planar electrodes that form three-dimensional (3D) DEP gates. This platform can continuously perform these tasks with a throughput of 3 ?L?min. Mixtures of latex particles, Escherichia coli Nissle, Lactobacillus, and Candida albicans are sorted and concentrated by these 3D DEP gates. Surface enhanced Raman scattering is used as an on-chip detection method on the concentrated bacteria. A processing rate of 500 bacteria was estimated when 100 ?l of a heterogeneous colony of 107 colony forming units ?ml was processed in a single pass within 30 min. PMID:19693376

  15. Multimodal focus attention and stress detection and feedback in an augmented driver simulator

    Microsoft Academic Search

    Alexandre Benoit; Laurent Bonnaud; Alice Caplier; Phillipe Ngo; Lionel Lawson; Daniela G. Trevisan; Vjekoslav Levacic; Céline Mancas; Guillaume Chanel

    2009-01-01

    This paper presents a driver simulator, which takes into account the information about the user’s state of mind (level of\\u000a attention, fatigue state, stress state). The user’s state of mind analysis is based on video data and biological signals.\\u000a Facial movements such as eyes blinking, yawning, head rotations, etc., are detected on video data: they are used in order\\u000a to

  16. Agroterrorism targeting livestock: a review with a focus on early detection systems.

    PubMed

    Elbers, Armin; Knutsson, Rickard

    2013-09-01

    Agroterrorism targeting livestock can be described as the intentional introduction of an animal disease agent against livestock with the purpose of causing economic damage, disrupting socioeconomic stability of a country, and creating panic and distress. This type of terrorism can be alluring to terrorists because animal disease agents are easily available. This review addresses the vulnerabilities of the livestock industry to agroterrorism. However, we also show that early detection systems have recently been developed for agroterrorism and deliberate spread of animal pathogens in livestock, including an agroterrorism intelligence cycle, syndromic surveillance programs, and computer-based clinical decision support systems that can be used for early detection of notifiable animal diseases. The development of DIVA-vaccines in the past 10 to 15 years has created, in principle, an excellent response instrument to counter intentional animal disease outbreaks. These developments have made our animal agriculture less vulnerable to agroterrorism. But we cannot relax; there are still many challenges, in particular with respect to integration of first line of defense, law enforcement, and early detection systems for animal diseases. PMID:23971814

  17. PLLA nanofibrous paper-based plasmonic substrate with tailored hydrophilicity for focusing SERS detection.

    PubMed

    Shao, Jundong; Tong, Liping; Tang, Siying; Guo, Zhinan; Zhang, Han; Li, Penghui; Wang, Huaiyu; Du, Chang; Yu, Xue-Feng

    2015-03-11

    We report a new paper-based surface enhanced Raman scattering (SERS) substrate platform contributed by a poly(l-lactic acid) (PLLA) nanofibrous paper adsorbed with plasmonic nanostructures, which can circumvent many challenges of the existing SERS substrates. This PLLA nanofibrous paper has three-dimensional porous structure, extremely clean surface with good hydrophobicity (contact angle is as high as 133.4°), and negligible background interference under Raman laser excitation. Due to the strong electrostatic interaction between PLLA nanofiber and cetyltrimethylammonium bromide (CTAB) molecules, the CTAB-coated gold nanorods (GNRs) are efficiently immobilized onto the fibers. Such a hydrophobic paper substrate with locally hydrophilic SERS-active area can confine analyte molecules and prevent the random spreading of molecules. The confinement leads to focusing effect and the GNRs-PLLA SERS substrate is found to be highly sensitive (0.1 nM Rhodamine 6G and malachite green) and exhibit excellent reproducibility (?8% relative standard deviation (RSD)) and long-term stability. Furthermore, it is also cost-efficient, with simple fabrication methodology, and demonstrates high sample collection efficiency. All of these benefits ensure that this GNRs-PLLA substrate is a really perfect choice for a variety of SERS applications. PMID:25697378

  18. Characterization of single ?-tracks by photoresist detection and AFM analysis-focus on biomedical science and technology

    NASA Astrophysics Data System (ADS)

    Falzone, Nadia; Myhra, Sverre; Chakalova, Radka; Hill, Mark A.; Thomson, James; Vallis, Katherine A.

    2013-11-01

    The interactions between energetic ions and biological and/or organic target materials have recently attracted theoretical and experimental attention, due to their implications for detector and device technologies, and for therapeutic applications. Most of the attention has focused on detection of the primary ionization tracks, and their effects, while recoil target atom tracks remain largely unexplored. Detection of tracks by a negative tone photoresist (SU-8), followed by standard development, in combination with analysis by atomic force microscopy, shows that both primary and recoil tracks are revealed as conical spikes, and can be characterized at high spatial resolution. The methodology has the potential to provide detailed information about single impact events, which may lead to more effective and informative detector technologies and advanced therapeutic procedures. In comparison with current characterization methods the advantageous features include: greater spatial resolution by an order of magnitude (20 nm) detection of single primary and associated recoil tracks; increased range of fluence (to 2.5 × 109 cm-2) sensitivity to impacts at grazing angle incidence; and better definition of the lateral interaction volume in target materials.

  19. Nanocrystalline tin oxide nanofibers deposited by a novel focused electrospinning method. Application to the detection of TATP precursors.

    PubMed

    Santos, José Pedro; Fernández, Maria Jesús; Fontecha, José Luis; Matatagui, Daniel; Sayago, Isabel; Horrillo, Maria Carmen; Gracia, Isabel

    2014-01-01

    A new method of depositing tin dioxide nanofibers in order to develop chemical sensors is presented. It involves an electrospinning process with in-plane electrostatic focusing over micromechanized substrates. It is a fast and reproducible method. After an annealing process, which can be performed by the substrate heaters, it is observed that the fibers are intertwined forming porous networks that are randomly distributed on the substrate. The fiber diameters oscillate from 100 nm to 200 nm and fiber lengths reach several tens of microns. Each fiber has a polycrystalline structure with multiple nano-grains. The sensors have been tested for the detection of acetone and hydrogen peroxide (precursors of the explosive triacetone triperoxide, TATP) in air in the ppm range. High and fast responses to these gases have been obtained. PMID:25521384

  20. Rapid Focused Sequencing: A Multiplexed Assay for Simultaneous Detection and Strain Typing of Bacillus anthracis, Francisella tularensis, and Yersinia pestis

    PubMed Central

    Zolotova, Anna; Tan, Eugene; Selden, Richard F.

    2013-01-01

    Background The intentional release of Bacillus anthracis in the United States in 2001 has heightened concern about the use of pathogenic microorganisms in bioterrorism attacks. Many of the deadliest bacteria, including the Class A Select Agents Bacillus anthracis, Francisella tularensis, and Yersinia pestis, are highly infectious via the pulmonary route when released in aerosolized form. Hence, rapid, sensitive, and reliable methods for detection of these biothreats and characterization of their potential impact on the exposed population are of critical importance to initiate and support rapid military, public health, and clinical responses. Methodology/Principal Findings We have developed microfluidic multiplexed PCR and sequencing assays based on the simultaneous interrogation of three pathogens per assay and ten loci per pathogen. Microfluidic separation of amplified fluorescently labeled fragments generated characteristic electrophoretic signatures for identification of each agent. The three sets of primers allowed significant strain typing and discrimination from non-pathogenic closely-related species and environmental background strains based on amplicon sizes alone. Furthermore, sequencing of the 10 amplicons per pathogen, termed “Rapid Focused Sequencing,” allowed an even greater degree of strain discrimination and, in some cases, can be used to determine virulence. Both amplification and sequencing assays were performed in microfluidic biochips developed for fast thermal cycling and requiring 7 µL per reaction. The 30-plex sequencing assay resulted in genotypic resolution of 84 representative strains belonging to each of the three biothreat species. Conclusions/Significance The microfluidic multiplexed assays allowed identification and strain differentiation of the biothreat agents Bacillus anthracis, Francisella tularensis, and Yersinia pestis and clear discrimination from closely-related species and several environmental background strains. The assays may be extended to detect a large number of pathogens, are applicable to the evaluation of both environmental and clinical samples, and have the potential to be applied in military, public health, and clinical diagnostic settings. PMID:23418519

  1. The Dense Plasma Focus Opportunities in Detection of Hidden Objects by Using Nanosecond Impulse Neutron Inspection System (NINIS)

    NASA Astrophysics Data System (ADS)

    Gribkov, V.; Dubrovsky, A.; Karpi?ski, L.; Miklaszewski, R.; Paduch, M.; Scholz, M.; Strzy?ewski, P.; Tomaszewski, K.

    2006-12-01

    Dense Plasma Focus device is proposed for use as a neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration. Our devices PF-6, recently put into operation at the Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland, and PF-10 belonging to the Institute for Theoretical and Experimental Physics, Moscow, Russia, have energy storages in its capacitor banks 7.4 kJ and 13 kJ as a maximum. Operated with the DPF chambers of a special design they have a current maximum up to ˜760 kA with a quarter period of the discharge equal to 1 microsecond. They generate circa 109 of 2.5-MeV neutrons in one pulse of ? 10-ns duration when working with deuterium, what permit to expect 1011 14-MeV neutrons at their operation with DT-mixture. This feature gives a principal possibility to create a "single-shot detection system" for interrogation of hidden objects. It means that all necessary information will be received during a single bright pulse of neutrons having duration in a nanosecond range by means of the time-of-flight technique with a short flight base. It might be a base for the creation of the Nanosecond Impulse Neutron Inspection System (NINIS). These characteristics of the neutron source open a number of opportunities while interrogation time in this case would now depend only on the data-processing system.

  2. Detection of Nitro-Based and Peroxide-Based Explosives by Fast Polarity-Switchable Ion Mobility Spectrometer with Ion Focusing in Vicinity of Faraday Detector

    PubMed Central

    Zhou, Qinghua; Peng, Liying; Jiang, Dandan; Wang, Xin; Wang, Haiyan; Li, Haiyang

    2015-01-01

    Ion mobility spectrometer (IMS) has been widely deployed for on-site detection of explosives. The common nitro-based explosives are usually detected by negative IMS while the emerging peroxide-based explosives are better detected by positive IMS. In this study, a fast polarity-switchable IMS was constructed to detect these two explosive species in a single measurement. As the large traditional Faraday detector would cause a trailing reactant ion peak (RIP), a Faraday detector with ion focusing in vicinity was developed by reducing the detector radius to 3.3?mm and increasing the voltage difference between aperture grid and its front guard ring to 591?V, which could remove trailing peaks from RIP without loss of signal intensity. This fast polarity-switchable IMS with ion focusing in vicinity of Faraday detector was employed to detect a mixture of 10?ng 2,4,6-trinitrotoluene (TNT) and 50?ng hexamethylene triperoxide diamine (HMTD) by polarity-switching, and the result suggested that [TNT-H]? and [HMTD+H]+ could be detected in a single measurement. Furthermore, the removal of trailing peaks from RIP by the Faraday detector with ion focusing in vicinity also promised the accurate identification of KClO4, KNO3 and S in common inorganic explosives, whose product ion peaks were fairly adjacent to RIP. PMID:26021282

  3. Magnetic resonance thermometry at 7T for real-time monitoring and correction of ultrasound induced mild hyperthermia.

    PubMed

    Fite, Brett Z; Liu, Yu; Kruse, Dustin E; Caskey, Charles F; Walton, Jeffrey H; Lai, Chun-Yen; Mahakian, Lisa M; Larrat, Benoit; Dumont, Erik; Ferrara, Katherine W

    2012-01-01

    While Magnetic Resonance Thermometry (MRT) has been extensively utilized for non-invasive temperature measurement, there is limited data on the use of high field (?7T) scanners for this purpose. MR-guided Focused Ultrasound (MRgFUS) is a promising non-invasive method for localized hyperthermia and drug delivery. MRT based on the temperature sensitivity of the proton resonance frequency (PRF) has been implemented in both a tissue phantom and in vivo in a mouse Met-1 tumor model, using partial parallel imaging (PPI) to speed acquisition. An MRgFUS system capable of delivering a controlled 3D acoustic dose during real time MRT with proportional, integral, and derivative (PID) feedback control was developed and validated. Real-time MRT was validated in a tofu phantom with fluoroptic temperature measurements, and acoustic heating simulations were in good agreement with MR temperature maps. In an in vivo Met-1 mouse tumor, the real-time PID feedback control is capable of maintaining the desired temperature with high accuracy. We found that real time MR control of hyperthermia is feasible at high field, and k-space based PPI techniques may be implemented for increasing temporal resolution while maintaining temperature accuracy on the order of 1°C. PMID:22536396

  4. In Vitro Investigation of the Individual Contributions of Ultrasound-Induced Stable and Inertial Cavitation in Targeted Drug Delivery.

    PubMed

    Gourevich, Dana; Volovick, Alexander; Dogadkin, Osnat; Wang, Lijun; Mulvana, Helen; Medan, Yoav; Melzer, Andreas; Cochran, Sandy

    2015-07-01

    Ultrasound-mediated targeted drug delivery is a therapeutic modality under development with the potential to treat cancer. Its ability to produce local hyperthermia and cell poration through cavitation non-invasively makes it a candidate to trigger drug delivery. Hyperthermia offers greater potential for control, particularly with magnetic resonance imaging temperature measurement. However, cavitation may offer reduced treatment times, with real-time measurement of ultrasonic spectra indicating drug dose and treatment success. Here, a clinical magnetic resonance imaging-guided focused ultrasound surgery system was used to study ultrasound-mediated targeted drug delivery in vitro. Drug uptake into breast cancer cells in the vicinity of ultrasound contrast agent was correlated with occurrence and quantity of stable and inertial cavitation, classified according to subharmonic spectra. During stable cavitation, intracellular drug uptake increased by a factor up to 3.2 compared with the control. Reported here are the value of cavitation monitoring with a clinical system and its subsequent employment for dose optimization. PMID:25887690

  5. Two-dimensional FDTD analysis of a pulsed microwave confocal system for breast cancer detection: fixed-focus and antenna-array sensors

    Microsoft Academic Search

    Susan C. Hagness; Allen Taflove; Jack E. Bridges

    1998-01-01

    A novel focused active microwave system is investigated for detecting tumors in the breast. In contrast to X-ray and ultrasound modalities, the method reviewed here exploits the breast-tissue physical properties unique to the microwave spectrum, namely, the translucent nature of normal breast tissues and the high dielectric contrast between malignant tumors and surrounding lesion-free normal breast tissues. The system uses

  6. A new multichannel time reversal focusing method for circumferential Lamb waves and its applications for defect detection in thick-walled pipe with large-diameter.

    PubMed

    Liu, Zenghua; Xu, Qinglong; Gong, Yu; He, Cunfu; Wu, Bin

    2014-09-01

    This paper proposes a new multichannel time reversal focusing (MTRF) method for circumferential Lamb waves which is based on modified time reversal algorithm and applies this method for detecting different kinds of defects in thick-walled pipe with large-diameter. The principle of time reversal of circumferential Lamb waves in pipe is presented along with the influence from multiple guided wave modes and propagation paths. Experimental study is carried out in a thick-walled and large-diameter pipe with three artificial defects, namely two axial notches on its inner and outer surface respectively, and a corrosion-like defect on its outer surface. By using the proposed MTRF method, the multichannel signals focus at the defects, leading to the amplitude improvement of the defect scattered signal. Besides, another energy focus arises in the direct signal due to the partial compensation of dispersion and multimode of circumferential Lamb waves, alongside the multichannel focusing, during MTRF process. By taking the direct focus as a time base, accurate defect localization is implemented. Secondly, a new phenomenon is exhibited in this paper that defect scattered wave packet appears just before the right boundary of truncation window after time reversal, and to which two feasible explanations are given. Moreover, this phenomenon can be used as the theoretical basis in the determination of defect scattered waves in time reversal response signal. At last, in order to detect defects without prior knowing their exact position, a large-range truncation window is used in the proposed method. As a result, the experimental operation of MTRF method is simplified and defect detection and localization are well accomplished. PMID:24877582

  7. MRI-guided targeted blood-brain barrier disruption with focused ultrasound: histological findings in rabbits.

    PubMed

    McDannold, Nathan; Vykhodtseva, Natalia; Raymond, Scott; Jolesz, Ferenc A; Hynynen, Kullervo

    2005-11-01

    Focused ultrasound offers a method to disrupt the blood-brain barrier (BBB) noninvasively and reversibly at targeted locations. The purpose of this study was to test the safety of this method by searching for ischemia and apoptosis in areas with BBB disruption induced by pulsed ultrasound in the presence of preformed gas bubbles and by looking for delayed effects up to one month after sonication. Pulsed ultrasound exposures (sonications) were performed in the brains of 24 rabbits under monitoring by magnetic resonance imaging (MRI) (ultrasound: frequency = 1.63 MHz, burst length = 100 ms, PRF = 1 Hz, duration = 20 s, pressure amplitude 0.7 to 1.0 MPa). Before sonication, an ultrasound contrast agent (Optison, GE Healthcare, Milwaukee, WI, USA) was injected IV. BBB disruption was confirmed with contrast-enhanced MR images. Whole brain histologic examination was performed using haematoxylin and eosin staining for general histology, vanadium acid fuchsin-toluidine blue staining for ischemic neurons and TUNEL staining for apoptosis. The main effects observed were tiny regions of extravasated red blood cells scattered around the sonicated locations, indicating affected capillaries. Despite these vasculature effects, only a few cells in some of the sonicated areas showed evidence for apoptosis or ischemia. No ischemic or apoptotic regions were detected that would indicate a compromised blood supply was induced by the sonications. No delayed effects were observed either by MRI or histology up to 4 wk after sonication. Ultrasound-induced BBB disruption is possible without inducing substantial vascular damage that would result in ischemic or apoptotic death to neurons. These findings indicate that this method is safe for targeted drug delivery, at least when compared with the currently available invasive methods. PMID:16286030

  8. Windows of detection of lorazepam in urine, oral fluid and hair, with a special focus on drug-facilitated crimes

    Microsoft Academic Search

    Pascal Kintz; Marion Villain; Vincent Cirimele; Gilbert Pépin; Bertrand Ludes

    2004-01-01

    The purported lowering of sex opposition, coupled with a possible abrupt unconsciousness-inducing effect and ease of administration in spiked drinks have resulted in the use of hypnotics in cases of drug-facilitated offense. Among these compounds, lorazepam possesses amnesic properties and can impair an individual rapidly.The chances to detect this substance increase if the most sensitive methods are used and if

  9. New pediatric vision screener employing polarization-modulated, retinal-birefringence-scanning-based strabismus detection and bull's eye focus detection with an improved target system: opto-mechanical design and operation.

    PubMed

    Irsch, Kristina; Gramatikov, Boris I; Wu, Yi-Kai; Guyton, David L

    2014-06-01

    Amblyopia ("lazy eye") is a major public health problem, caused by misalignment of the eyes (strabismus) or defocus. If detected early in childhood, there is an excellent response to therapy, yet most children are detected too late to be treated effectively. Commercially available vision screening devices that test for amblyopia's primary causes can detect strabismus only indirectly and inaccurately via assessment of the positions of external light reflections from the cornea, but they cannot detect the anatomical feature of the eyes where fixation actually occurs (the fovea). Our laboratory has been developing technology to detect true foveal fixation, by exploiting the birefringence of the uniquely arranged Henle fibers delineating the fovea using retinal birefringence scanning (RBS), and we recently described a polarization-modulated approach to RBS that enables entirely direct and reliable detection of true foveal fixation, with greatly enhanced signal-to-noise ratio and essentially independent of corneal birefringence (a confounding variable with all polarization-sensitive ophthalmic technology). Here, we describe the design and operation of a new pediatric vision screener that employs polarization-modulated, RBS-based strabismus detection and bull's eye focus detection with an improved target system, and demonstrate the feasibility of this new approach. PMID:24911020

  10. New pediatric vision screener employing polarization-modulated, retinal-birefringence-scanning-based strabismus detection and bull's eye focus detection with an improved target system: opto-mechanical design and operation

    NASA Astrophysics Data System (ADS)

    Irsch, Kristina; Gramatikov, Boris I.; Wu, Yi-Kai; Guyton, David L.

    2014-06-01

    Amblyopia ("lazy eye") is a major public health problem, caused by misalignment of the eyes (strabismus) or defocus. If detected early in childhood, there is an excellent response to therapy, yet most children are detected too late to be treated effectively. Commercially available vision screening devices that test for amblyopia's primary causes can detect strabismus only indirectly and inaccurately via assessment of the positions of external light reflections from the cornea, but they cannot detect the anatomical feature of the eyes where fixation actually occurs (the fovea). Our laboratory has been developing technology to detect true foveal fixation, by exploiting the birefringence of the uniquely arranged Henle fibers delineating the fovea using retinal birefringence scanning (RBS), and we recently described a polarization-modulated approach to RBS that enables entirely direct and reliable detection of true foveal fixation, with greatly enhanced signal-to-noise ratio and essentially independent of corneal birefringence (a confounding variable with all polarization-sensitive ophthalmic technology). Here, we describe the design and operation of a new pediatric vision screener that employs polarization-modulated, RBS-based strabismus detection and bull's eye focus detection with an improved target system, and demonstrate the feasibility of this new approach.

  11. Detection of ultrasound-modulated photons in diffuse media using the photorefractive effect

    Microsoft Academic Search

    Todd W. Murray; Lei Sui; Gopi Maguluri; Ronald A. Roy; Alex Nieva; Florian Blonigen; Charles A. Dimarzio

    2004-01-01

    Ultrasound-modulated optical tomography is a dual-wave sensing technique in which diffusive light in a turbid medium interacts with an imposed acoustic field. A phase-modulated photon field emanates from the interaction region and carries with it information about the optomechanical properties of the medium. We present a technique for detection of ultrasound-induced optical phase modulation using an adaptive, photorefractive-crystal-based interferometry system.

  12. Focused ion beam-fabricated Au micro/nanostructures used as a surface enhanced Raman scattering-active substrate for trace detection of molecules and influenza virus.

    PubMed

    Lin, Ying-Yi; Liao, Jiunn-Der; Ju, Yu-Hung; Chang, Chia-Wei; Shiau, Ai-Li

    2011-05-01

    The focused ion beam (FIB) technique was used to precisely fabricate patterned Au micro/nanostructures (fibAu). The effects of surface enhanced Raman scattering (SERS) on the fibAu samples were investigated by adjusting the geometrical, dimensional, and spacing factors. The SERS mechanism was evaluated using low-concentration rhodamine 6G (R6G) molecules, physically adsorbed or suspended on/within the micro/nanostructures. The results indicated that for detecting R6G molecules, hexagon-like micro/nanostructures induced a higher electromagnetic mechanism (EM) due to the availability of multiple edges and small curvature. By decreasing the dimensions from 300 to 150 nm, the laser-focused area contained an increasing number of micro/nanostructures and therefore intensified the excitation of SERS signals. Moreover, with an optimized geometry and dimensions of the micro/nanostructures, the relative intensity/surface area value reached a maximum as the spacing was 22 nm. An exponential decrease was found as the spacing was increased, which most probably resulted from the loss of EM. The spacing between the micro/nanostructures upon the fibAu was consequently regarded as the dominant factor for the detection of R6G molecules. By taking an optimized fibAu to detect low-concentration influenza virus, the amino acids from the outermost surface of the virus can be well distinguished through the SERS mechanism. PMID:21427472

  13. Predicting focus through prominence structure 

    E-print Network

    Calhoun, Sasha

    2007-01-01

    Focus is central to our control of information flow in dialogue. Spoken language understanding systems therefore need to be able to detect focus automatically. It is well known that prominence is a key marker of focus ...

  14. Analysis of global Terrestrial Gamma Ray Flashes distribution and special focus on AGILE detections over South America

    NASA Astrophysics Data System (ADS)

    Fabró, Ferran; Montanyà, Joan; Marisaldi, Martino; van der Velde, Oscar A.; Fuschino, Fabio

    2015-03-01

    Global distribution of the Terrestrial Gamma-ray Flashes (TGFs) detected by AGILE and RHESSI for the period from March 2009 to July 2012 has been analysed. A fourth TGF production region has been distinguished over the Pacific. It is confirmed that TGF occurrence follows the Intertropical Convergence Zone (ITCZ) seasonal migration and prefers afternoons. TGF/lightning ratio appears to be lower over America than other regions suggesting that meteorological regional differences are important for the TGF production. Diurnal cycle of TGFs peaks in the afternoon suggesting that Convective Available Potential Energy (CAPE) and convection are important for TGF production. Moreover all AGILE passages over South America in the same period have been analysed to find meteorological preferences for TGF occurrence. In each passage the analysis of Cloud Top Altitude (CTA), CAPE, number of strokes, number of storms and coverage area of clouds with temperatures below -70 °C (Cloud Top Coverage area, CTC) are computed. On average, AGILE has been exposed to 19,100 strokes between each TGF representing ?68 h of exposure over active storms. High CAPE values, high cloud tops and high stroke occurrence suggest that meteorological conditions conducive to vigorous and electrically active storms are important for TGF production. It is shown that a high number of thunderstorms is preferable for TGF production which may be explained by a greater chance of the presence of a thunderstorm in the best development stage for TGF production. High tropopause altitude seems to be important but not primordial for TGF production.

  15. Capillary isoelectric focusing of microorganisms in the pH range 2-5 in a dynamically modified FS capillary with UV detection.

    PubMed

    Horká, Marie; R?zicka, Filip; Holá, Veronika; Slais, Karel

    2006-07-01

    The isoelectric points of many microbial cells lie within the pH range spanning from 1.5 to 4.5. In this work, we suggest a CIEF method for the separation of cells according to their isoelectric points in the pH range of 2-5. It includes the segmental injection of the sample pulse composed of the segment of the selected simple ampholytes, the segment of the bioanalytes and the segment of carrier ampholytes into fused silica capillaries dynamically modified by poly(ethylene glycole). This polymer dissolved in the catholyte, in the anolyte and in the injected sample pulse was used for a prevention of the bioanalyte adsorption on the capillary surface and for the reduction of the electroosmotic flow. Between each focusing run, the capillaries were washed with the mixture of acetone/ethanol to achieve the reproducible and efficient CIEF. In order to trace of pH gradients, low-molecular-mass pI markers were used. The mixed cultures of microorganisms, Escherichia coli CCM 3954, Candida albicans CCM 8180, Candida parapsilosis, Candida krusei, Candida glabrata, Candida tropicalis, CCM 8223, Proteus vulgaris, Klebsiela pneumoniae, Staphylococcus aureus CCM 3953, Streptococcus agalactiae CCM 6187, Enterococcus faecalis CCM 4224 and Staphylococcus epidermidis CCM 4418, were focused and separated by the CIEF method suggested here. This CIEF method enables the separation and detection of the microbes from the mixed cultures within several minutes. The minimum detectable number of microbial cells was less than 10(3). PMID:16791563

  16. Nested Polymerase Chain Reaction and Sequence- Based Detection of Leishmania Infection of Sand Flies in Recently Emerged Endemic Focus of Zoonotic Cutaneous Leishmaniasis, Southern Iran

    PubMed Central

    Azizi, Kourosh; Badzohreh, Abdollah; Sarkari, Bahador; Fakoorziba, Mohammad Reza; Kalantari, Mohsen; Moemenbellah-Fard, Mohammad Djaefar; Ali-Akbarpour, Mohsen

    2013-01-01

    Background: Geographical distribution of zoonotic cutaneous leishmaniasis (ZCL) has continuously been extended in recent years in Iran. The Beiza District is one of the newly-emerged endemic foci of ZCL in southern Iran. The main aim of the present study was to detect the vector(s) of ZCL in this area. Methods: To detect the fauna and vectors of ZCL in this district, sand flies were caught using sticky papers. Seventy randomly selected female sand flies out of 730 were molecularly investigated for Leishmania infection using species-specific nested polymerase chain reaction (PCR) assay between April and October 2010. Results: A total of 2543 sand flies were caught. The fauna was identified as 10 species (five Phlebotomus spp. and five Sergentomyia spp.). Phlebotomus papatasi was the most dominant species both indoors and outdoors (37.55% and 16.35 %, respectively). L. major was detected in 5 out of 48 investigated Phlebotomus papatasi (10.41%). Sequence-based characterization was carried out to confirm the PCR findings. The positive samples were shown to have 75-88% similarity with L. major sequences in GenBank. Conclusion: According to the findings of the present study, similar to the other foci of ZCL in Iran, P. papatasi is the proven and primary vector of CL. This study could be drawn upon for future strategy planning in this newly emerged endemic focus. PMID:24031105

  17. FindFoci: A Focus Detection Algorithm with Automated Parameter Training That Closely Matches Human Assignments, Reduces Human Inconsistencies and Increases Speed of Analysis

    PubMed Central

    Herbert, Alex D.; Carr, Antony M.; Hoffmann, Eva

    2014-01-01

    Accurate and reproducible quantification of the accumulation of proteins into foci in cells is essential for data interpretation and for biological inferences. To improve reproducibility, much emphasis has been placed on the preparation of samples, but less attention has been given to reporting and standardizing the quantification of foci. The current standard to quantitate foci in open-source software is to manually determine a range of parameters based on the outcome of one or a few representative images and then apply the parameter combination to the analysis of a larger dataset. Here, we demonstrate the power and utility of using machine learning to train a new algorithm (FindFoci) to determine optimal parameters. FindFoci closely matches human assignments and allows rapid automated exploration of parameter space. Thus, individuals can train the algorithm to mirror their own assignments and then automate focus counting using the same parameters across a large number of images. Using the training algorithm to match human assignments of foci, we demonstrate that applying an optimal parameter combination from a single image is not broadly applicable to analysis of other images scored by the same experimenter or by other experimenters. Our analysis thus reveals wide variation in human assignment of foci and their quantification. To overcome this, we developed training on multiple images, which reduces the inconsistency of using a single or a few images to set parameters for focus detection. FindFoci is provided as an open-source plugin for ImageJ. PMID:25478967

  18. Prostatic cancer surveillance following whole-gland high-intensity focused ultrasound: comparison of MRI and prostate-specific antigen for detection of residual or recurrent disease

    PubMed Central

    Punwani, S; Emberton, M; Walkden, M; Sohaib, A; Freeman, A; Ahmed, H; Allen, C; Kirkham, A

    2012-01-01

    Objective This retrospective study compares dynamic contrast-enhanced (DCE) MRI with the serial prostate-specific antigen (PSA) measurement for detection of residual disease following whole-gland high-intensity focused ultrasound (HIFU) therapy of prostate cancer. Methods Patients in whom post-HIFU DCE-MRI was followed within 3 months by ultrasound-guided transrectal biopsy were selected from a local database. 26 patients met the study inclusion criteria. Serial PSA levels following HIFU and post-HIFU follow-up MRI were retrieved for each patient. Three radiologists unaware of other investigative results independently assessed post-HIFU MRI studies for the presence of cancer, scoring on a four-point scale (1, no disease; 2, probably no disease; 3, probably residual disease; and 4, residual disease). Sensitivity, specificity and receiver operating characteristic (ROC) analysis were performed for each reader, post-HIFU PSA nadir and pre-biopsy PSA level thresholds of >0.2 and >0.5 ng ml?1. Results The sensitivity of DCE-MRI for detection of residual disease for the three readers ranged between 73% and 87%, and the specificity between 73% and 82%. There was good agreement between readers (?=0.69–0.77). The sensitivity and specificity of PSA thresholds was 60–87% and 73–100%, respectively. The area under the ROC curve was greatest for pre-biopsy PSA (0.95). Conclusion DCE-MRI performed following whole-gland HIFU has similar sensitivity and specificity and ROC performance to serial PSA measurements for detection of residual or recurrent disease. PMID:22253342

  19. Particle focusing in microfluidic devices

    Microsoft Academic Search

    Xiangchun Xuan; Junjie Zhu; Christopher Church

    2010-01-01

    Focusing particles (both biological and synthetic) into a tight stream is usually a necessary step prior to counting, detecting,\\u000a and sorting them. The various particle focusing approaches in microfluidic devices may be conveniently classified as sheath\\u000a flow focusing and sheathless focusing. Sheath flow focusers use one or more sheath fluids to pinch the particle suspension\\u000a and thus focus the suspended

  20. Molecular detection and identification of Leishmania infection in naturally infected sand flies in a focus of cutaneous leishmaniasis in northern Morocco

    PubMed Central

    2014-01-01

    Background Cutaneous leishmaniasis is an infectious disease caused by various species of the flagellate protozoan Leishmania. During the past 20 years, cutaneous leishmaniasis has emerged as a major public health threat in Morocco. The main objective of this study was to study the occurrence of Leishmania infection in vectors and to identify sand fly blood meal sources in an endemic locality of cutaneous leishmaniasis within Sefrou province, where the vectors of leishmaniasis were still unknown. Methods 2650 sand flies were collected using CDC miniature light traps and identified morphologically. The identified sand flies were tested for Leishmania infection by nested PCR. The source of blood meal of 10 freshly engorged females: 6 Phlebotomus longicuspis and 4 Phlebotomus sergenti, was determined using the Cyt b sequence. Results The collected sand flies consisted of 10 species, seven of which belonged to the genus Phlebotomus and three to the genus Sergentomyia. The most abundant species was P. longicuspis, accounting for 72% of the total sand flies collected. In females of three P. longicuspis and four P. sergenti, Leishmania infantum and Leishmania tropica DNA was detected, respectively. The source of blood meal of engorged females showed that all sand flies tested fed on humans. Conclusions We report for the first time the natural infection of P. longicuspis with L. infantum in Morocco. The high frequency of this species in this region, in addition to its anthropophilic character make P. longicuspis the putative vector of L. infantum in this cutaneous leishmaniasis focus where L. tropica is confirmed as the causative agent of the disease and P. sergenti as its vector. The presence of L. infantum, and its presumed vector in this area, makes this a site of high risk of visceral leishmaniasis, mostly because of the proximity of a focus of human and canine visceral leishmaniasis. PMID:24990497

  1. A Focus on Focus Groups.

    ERIC Educational Resources Information Center

    Quible, Zane K.

    1998-01-01

    Argues that focus groups provide users with valuable qualitative data not readily obtained with any other data-collection technique. Describes the focus-group process, including participant selection, moderator role, phases of the process, and advantages and disadvantages. Suggests ways that business communication instructors can incorporate the…

  2. Faculty Focus

    NSDL National Science Digital Library

    Faculty Focus, a frequently updated, multifaceted blog from Magna Publications, is a must read for college educators who want to stay up on trends, resources, and teaching techniques. With almost two-dozen carefully chosen topics listed on the homepage, academics are sure to find something to pique their interest and stretch their knowledge. Check out App of the Week for tips on education-friendly applications for your phone, tablet, and computer. Next, take a look at the Online Education section, penned by professors experimenting with web-based formats. Creating a free account with the site allows readers to access Free Reports, a compendium of dozens of reports on topics relevant to higher education, each packed with ten to twelve citations for further investigation. The White Papers section is another excellent resource that examines some of the most important issues in academia; however, this service is available for a fee.

  3. Fast detection of Candida albicans and/or bacteria in blood plasma by "sample-self-focusing" using capillary electrophoresis-laser-induced fluorescence.

    PubMed

    Tong, Man-Yung; Jiang, Chunxia; Armstrong, Daniel W

    2010-09-21

    Detection of microbial contamination in blood plasma is critical and necessary in different medical and research fields. Most of the current standard procedures for the detection of bacteria and fungi can be time-consuming, for example, direct inoculation methods of microbial cultures in respective growth media can take a few days to several weeks. A fast analysis method with high sensitivity output such as CE-laser-induced fluorescence becomes an attractive alternative. Previously, a spacer-injection method with the use of zwitterionic surfactant (SB3-10) as a blocking agent to negate the cells' mobility, induce aggregation and single microbial peak formation in a buffer solution was reported. Here, a fast, simple direct method for microbial detection in blood plasma without using the spacer and blocking agent is reported. To compensate for the natural electrophoretic heterogeneity of microbes, a CTAB additive was used to sweep all microbial cells towards the plasma peak where a single sharp microbial peak is formed and detected. With the use of BacLight Green bacterial stain, the microbial peak, generally, can be detected within 10 min in front of the plasma peak using capillary electrophoresis coupled with laser-induced fluorescence detection. The LOD of microbes detectable were 5 cells per injection. This technique provides a great advantage over traditional, time-consuming microbial inoculation methods. PMID:20363575

  4. Impact of multiple biopsy cores on predicting final tumor volume in prostate cancer detected by a single microscopic focus of cancer on biopsy

    Microsoft Academic Search

    Thomas J. Guzzo; Manish Vira; Wei-Ting Hwang; Anthony D’amico; John Tomaszewski; Richard Whittington; Alan J. Wein; Keith Vanarsdalen; S. Bruce Malkowicz

    2005-01-01

    ObjectivesTo compare the impact that the number of biopsy cores have on final pathologic findings when minimal disease is detected at biopsy. Discordance has been noted between transrectal ultrasound-guided biopsy results and tumor volume even when minimal amounts of tumor are found on biopsy.

  5. Synthesis of grafted phosphorylcholine polymer layers as specific recognition ligands for C-reactive protein focused on grafting density and thickness to achieve highly sensitive detection.

    PubMed

    Kamon, Yuri; Kitayama, Yukiya; Itakura, Akiko N; Fukazawa, Kyoko; Ishihara, Kazuhiko; Takeuchi, Toshifumi

    2015-04-21

    We studied the effects of layer thickness and grafting density of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) thin layers as specific ligands for the highly sensitive binding of C-reactive protein (CRP). PMPC layer thickness was controlled by surface-initiated activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP). PMPC grafting density was controlled by utilizing mixed self-assembled monolayers with different incorporation ratios of the bis[2-(2-bromoisobutyryloxy)undecyl] disulfide ATRP initiator, as modulated by altering the feed molar ratio with (11-mercaptoundecyl)tetra(ethylene glycol). X-ray photoelectron spectroscopy and ellipsometry measurements were used to characterize the modified surfaces. PMPC grafting densities were estimated from polymer thickness and the molecular weight obtained from sacrificial initiator during surface-initiated AGET ATRP. The effects of thickness and grafting density of the obtained PMPC layers on CRP binding performance were investigated using surface plasmon resonance employing a 10 mM Tris-HCl running buffer containing 140 mM NaCl and 2 mM CaCl2 (pH 7.4). Furthermore, the non-specific binding properties of the obtained layers were investigated using human serum albumin (HSA) as a reference protein. The PMPC layer which has 4.6 nm of thickness and 1.27 chains per nm(2) of grafting density showed highly sensitive CRP detection (limit of detection: 4.4 ng mL(-1)) with low non-specific HSA adsorption, which was improved 10 times than our previous report of 50 ng mL(-1). PMID:25783194

  6. Chromosome-Directed PCR-Based Detection and Quantification of Bacillus cereus Group Members with Focus on B. thuringiensis Serovar israelensis Active against Nematoceran Larvae.

    PubMed

    Schneider, Salome; Hendriksen, Niels B; Melin, Petter; Lundström, Jan O; Sundh, Ingvar

    2015-08-01

    Bacillus thuringiensis serovar israelensis is a wide-spread soil bacterium affiliated with the B. cereus group (Bcg) and is widely used in biocontrol products applied against mosquito and black fly larvae. For monitoring and quantification of applied B. thuringiensis serovar israelensis and its effect on indigenous B. thuringiensis serovar israelensis and Bcg assemblages, efficient and reliable tools are essential. The abundance and properties of B. thuringiensis serovar israelensis strains in the environment traditionally have been investigated with cultivation-dependent techniques, which are hampered by low sensitivity and the morphological similarity between B. cereus and B. thuringiensis. Currently available PCR-based detection and quantification tools target markers located on plasmids. In this study, a new cultivation-independent PCR-based method for efficient and specific quantification of B. thuringiensis serovar israelensis and Bcg is presented, utilizing two sets of PCR primers targeting the bacterial chromosome. Sequence database searches and empirical tests performed on target and nontarget species, as well as on bulk soil DNA samples, demonstrated that this diagnostic tool is specific for B. thuringiensis serovar israelensis and Bcg. The method will be useful for comparisons of Bcg and B. thuringiensis serovar israelensis abundances in the same samples. Moreover, the effect of B. thuringiensis serovar israelensis-based insecticide application on the total Bcg assemblages, including indigenous populations, can be investigated. This type of information is valuable in risk assessment and policy making for use of B. thuringiensis serovar israelensis in the environment. PMID:25979887

  7. Molecular Phylogeny of the Lactuca Alliance (Cichorieae Subtribe Lactucinae, Asteraceae) with Focus on Their Chinese Centre of Diversity Detects Potential Events of Reticulation and Chloroplast Capture

    PubMed Central

    Wang, Ze-Huan; Peng, Hua; Kilian, Norbert

    2013-01-01

    The first comprehensive molecular phylogenetic reconstruction of the Cichorieae subtribe Lactucinae is provided. Sequences for two datasets, one of the nuclear rDNA ITS region, the other of five concatenated non-coding chloroplast DNA markers including the petD region and the psbA-trnH, 5?trnL(UAA)-trnF, rpl32-trnL(UAG) and trnQ(UUG)-5?rps16 spacers, were, with few exceptions, newly generated for 130 samples of 78 species. The sampling spans the entire subtribe Lactucinae while focusing on its Chinese centre of diversity; more than 3/4 of the Chinese Lactucinae species are represented. The nuclear and plastid phylogenies inferred from the two independent datasets show various hard topological incongruences. They concern the internal topology of major lineages, in one case the placement of taxa in major lineages, the relationships between major lineages and even the circumscription of the subtribe, indicating potential events of ancient as well as of more recent reticulation and chloroplast capture in the evolution of the subtribe. The core of the subtribe is clearly monophyletic, consisting of the six lineages, Cicerbita, Cicerbita II, Lactuca, Melanoseris, Notoseris and Paraprenanthes. The Faberia lineage and the monospecific Prenanthes purpurea lineage are part of a monophyletic subtribe Lactucinae only in the nuclear or plastid phylogeny, respectively. Morphological and karyological support for their placement is considered. In the light of the molecular phylogenetic reconstruction and of additional morphological data, the conflicting taxonomies of the Chinese Lactuca alliance are discussed and it is concluded that the major lineages revealed are best treated at generic rank. An improved species level taxonomy of the Chinese Lactucinae is outlined; new synonymies and some new combinations are provided. PMID:24376566

  8. Acoustic characterization of high intensity focused ultrasound fields: a combined measurement and modeling approach.

    PubMed

    Canney, Michael S; Bailey, Michael R; Crum, Lawrence A; Khokhlova, Vera A; Sapozhnikov, Oleg A

    2008-10-01

    Acoustic characterization of high intensity focused ultrasound (HIFU) fields is important both for the accurate prediction of ultrasound induced bioeffects in tissues and for the development of regulatory standards for clinical HIFU devices. In this paper, a method to determine HIFU field parameters at and around the focus is proposed. Nonlinear pressure waveforms were measured and modeled in water and in a tissue-mimicking gel phantom for a 2 MHz transducer with an aperture and focal length of 4.4 cm. Measurements were performed with a fiber optic probe hydrophone at intensity levels up to 24,000 W/cm(2). The inputs to a Khokhlov-Zabolotskaya-Kuznetsov-type numerical model were determined based on experimental low amplitude beam plots. Strongly asymmetric waveforms with peak positive pressures up to 80 MPa and peak negative pressures up to 15 MPa were obtained both numerically and experimentally. Numerical simulations and experimental measurements agreed well; however, when steep shocks were present in the waveform at focal intensity levels higher than 6000 W/cm(2), lower values of the peak positive pressure were observed in the measured waveforms. This underrepresentation was attributed mainly to the limited hydrophone bandwidth of 100 MHz. It is shown that a combination of measurements and modeling is necessary to enable accurate characterization of HIFU fields. PMID:19062878

  9. Acoustic characterization of high intensity focused ultrasound fields: A combined measurement and modeling approach

    PubMed Central

    Canney, Michael S.; Bailey, Michael R.; Crum, Lawrence A.; Khokhlova, Vera A.; Sapozhnikov, Oleg A.

    2008-01-01

    Acoustic characterization of high intensity focused ultrasound (HIFU) fields is important both for the accurate prediction of ultrasound induced bioeffects in tissues and for the development of regulatory standards for clinical HIFU devices. In this paper, a method to determine HIFU field parameters at and around the focus is proposed. Nonlinear pressure waveforms were measured and modeled in water and in a tissue-mimicking gel phantom for a 2 MHz transducer with an aperture and focal length of 4.4 cm. Measurements were performed with a fiber optic probe hydrophone at intensity levels up to 24 000 W?cm2. The inputs to a Khokhlov–Zabolotskaya–Kuznetsov-type numerical model were determined based on experimental low amplitude beam plots. Strongly asymmetric waveforms with peak positive pressures up to 80 MPa and peak negative pressures up to 15 MPa were obtained both numerically and experimentally. Numerical simulations and experimental measurements agreed well; however, when steep shocks were present in the waveform at focal intensity levels higher than 6000 W?cm2, lower values of the peak positive pressure were observed in the measured waveforms. This underrepresentation was attributed mainly to the limited hydrophone bandwidth of 100 MHz. It is shown that a combination of measurements and modeling is necessary to enable accurate characterization of HIFU fields. PMID:19062878

  10. Movement out of focus

    E-print Network

    Erlewine, Michael Yoshitaka

    2014-01-01

    This dissertation investigates the consequences of overt and covert movement on association with focus. The interpretation of focus-sensitive operators such as only and even depends on the presence of a focused constituent ...

  11. Alternating phase focused linacs

    DOEpatents

    Swenson, Donald A. (Los Alamos, NM)

    1980-01-01

    A heavy particle linear accelerator employing rf fields for transverse and ongitudinal focusing as well as acceleration. Drift tube length and gap positions in a standing wave drift tube loaded structure are arranged so that particles are subject to acceleration and succession of focusing and defocusing forces which contain the beam without additional magnetic or electric focusing fields.

  12. Focus Training Manual; A Focus Dissemination Project.

    ERIC Educational Resources Information Center

    Human Resource Associates, Inc., Hastings, Minn.

    This training manual is for use in preparing staff members to use the Focus Model, which is a "school within a school" for disaffected high school students. The material is designed to be used as a resource aid following participation in an in-service workshop. The first section presents general and administrative preadoption material, including a…

  13. Detection of non-cavitated approximal caries lesions in digital images from seven solid-state receptors with particular focus on task-specific enhancement filters. An ex vivo study in human teeth.

    PubMed

    Haiter-Neto, Francisco; dos Anjos Pontual, Andrea; Frydenberg, Morten; Wenzel, Ann

    2008-09-01

    The aim of this study was to compare detection of non-cavitated approximal caries lesions in images from seven solid-state intraoral digital receptors, with particular focus on two task-specific enhancement filters. One hundred and sixty approximal non-cavitated surfaces were radiographed under standardized conditions using the following seven intraoral solid-state digital receptors: two CMOS systems, Schick CDR-APS, and Kodak RVGui; and five CCD systems: Visualix, VistaRay, Dixi2, Sidexis, and Dr. Suni Plus. The Kodak RVGui digital images were captured with two task-specific, predefined enhancement filters ("dento-enamel" and "periodontal"). Eight observers examined the digital images for the presence or absence of approximal carious lesions. The teeth were subsequently sectioned for histological analysis, which served as the "gold standard" for the radiographic examination and allowed for a calculation of sensitivity, specificity, and overall accuracy. Both RVG modalities obtained the highest sensitivity values, which were significantly higher than with Visualix, Sidexis, and VistaRay images (all P0.05). PMID:18210170

  14. Use of ionic liquid aggregates of 1-hexadecyl-3-butyl imidazolium bromide in a focused-microwave assisted extraction method followed by high-performance liquid chromatography with ultraviolet and fluorescence detection to determine the 15 + 1 EU priority PAHs in toasted cereals (“gofios”)

    Microsoft Academic Search

    Mónica Germán-Hernández; Verónica Pino; Jared L. Anderson; Ana M. Afonso

    2011-01-01

    A focused-microwave assisted extraction method using aggregates of the ionic liquid (IL) 1-hexadecyl-3-butylimidazolium bromide (HDBIm-Br) followed by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection and single-channel fluorescence detection (FLD) has been developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in toasted cereals (“gofios”) of different nature (wheat, barley, rye, and maize corn) from the Canary Islands, Spain. The

  15. Controlling Electron-Beam-Weld Focus

    NASA Technical Reports Server (NTRS)

    Coate, F. M.

    1982-01-01

    Control loop measures weld-spot temperature to regulate focus current. Square-wave generator modulates current in electron-beam focus coil so that focal point is varied between points slightly above and below surface of weld. Sensor detects intensity of light emitted by weld, proportional to fourth power of temperature at hottest part of weld spot. Sensor signal is detected by chopper demodulator synchronized by square-wave generator, to determine whether average position of focal point is higher than, coincident with, or lower than optimum point; and focus coil current is adjusted accordingly.

  16. Foreign Policy In Focus

    NSDL National Science Digital Library

    Foreign Policy In Focus (FPIF), a cooperative project of two independent foreign policy research and analysis institutions--the Interhemispheric Resource Center and the Institute for Policy Studies, aims to provide the public and policy-makers with "recommendations for a more responsible and visionary US foreign policy." The FPIF project publishes a series of In Focus policy briefs as well as an electronic newsletter entitled The Progressive Response, which summarizes the In Focus briefs and informs readers about new developments in policy issues. Recent In Focus briefs include "US Russia Security Relations," "Aid to Russia," "Drug Certification," and "Democratizing the Trade Debate."

  17. Agreement, Shells, and Focus.

    ERIC Educational Resources Information Center

    Simpson, Andrew; Wu, Zoe

    2002-01-01

    Reconsiders development and licensing of agreement as a syntactic projection and argues for a productive developmental relation between agreement and the category of focus. Suggests that focus projections are initially selected by a variety of functional heads with real semantic content, then, over time decays into a simple concord shell. Upon…

  18. Focus, 2000-2001.

    ERIC Educational Resources Information Center

    Focus, 2001

    2001-01-01

    These three issues of 2000-2001 "Focus" present a collection of papers focusing on issues related to poverty. The first issue discusses child support enforcement policy and low-income families, highlighting such issues as fragile families and child wellbeing; low-income families and the child support enforcement system; child support enforcement…

  19. OECD Focus Hot File

    NSDL National Science Digital Library

    In each issue of the Organization for Economic Co-operation and Development (OECD)'s Focus Hot File, recent books and government reports of interest are listed with summaries and contact information. Past listings may be browsed by country in the Focus Compendium, and related publications are hyperlinked throughout.

  20. Microfabricated particle focusing device

    DOEpatents

    Ravula, Surendra K.; Arrington, Christian L.; Sigman, Jennifer K.; Branch, Darren W.; Brener, Igal; Clem, Paul G.; James, Conrad D.; Hill, Martyn; Boltryk, Rosemary June

    2013-04-23

    A microfabricated particle focusing device comprises an acoustic portion to preconcentrate particles over large spatial dimensions into particle streams and a dielectrophoretic portion for finer particle focusing into single-file columns. The device can be used for high throughput assays for which it is necessary to isolate and investigate small bundles of particles and single particles.

  1. STRATEGIC FOCUS: Digital `Everyware'

    E-print Network

    network mapping tools to help women researchers locate potential research collaborators. I Mathematics Professor Eliza Michalopoulou uses mathematical modeling and signal processing to help the Navy detect

  2. Flat focusing mirror.

    PubMed

    Cheng, Y C; Kicas, S; Trull, J; Peckus, M; Cojocaru, C; Vilaseca, R; Drazdys, R; Staliunas, K

    2014-01-01

    The control of spatial propagation properties of narrow light beams such as divergence, focusing or imaging are main objectives in optics and photonics. In this letter, we propose and demonstrate experimentally a flat focusing mirror, based on an especially designed dielectric structure without any optical axis. More generally, it also enables imaging any light pattern in reflection. The flat focusing mirror with a transversal invariance can largely increase the applicability of structured photonic materials for light beam propagation control in small-dimension photonic circuits. PMID:25228358

  3. Conservation Focus and Executive

    E-print Network

    Northwest Power and Conservation Council Focus and Executive Summary Background Power Committee Walla Walla May 12, 2009 #12;Northwest Power and Conservation Council Conditions Facing the Region and Conservation Council Resource Alternatives · Increased cost-effective efficiency potential ­ Technological

  4. Facility Focus: Food Service.

    ERIC Educational Resources Information Center

    College Planning & Management, 2002

    2002-01-01

    Describes the Hawthorn Court Community Center at Iowa State University, Ames, and the HUB-Robeson Center at Pennsylvania State University. Focuses on the food service offered in these new student-life buildings. Includes photographs. (EV)

  5. Inertial Focusing in Microfluidics

    PubMed Central

    Martel, Joseph M.; Toner, Mehmet

    2015-01-01

    When Segré and Silberberg in 1961 witnessed particles in a laminar pipe flow congregating at an annulus in the pipe, scientists were perplexed and spent decades learning why such behavior occurred, finally understanding that it was caused by previously unknown forces on particles in an inertial flow. The advent of microfluidics opened a new realm of possibilities for inertial focusing in the processing of biological fluids and cellular suspensions and created a field that is now rapidly expanding. Over the past five years, inertial focusing has enabled high-throughput, simple, and precise manipulation of bodily fluids for a myriad of applications in point-of-care and clinical diagnostics. This review describes the theoretical developments that have made the field of inertial focusing what it is today and presents the key applications that will make inertial focusing a mainstream technology in the future. PMID:24905880

  6. Final focus nomenclature

    SciTech Connect

    Erickson, R.

    1986-08-08

    The formal names and common names for all devices in the final focus system of the SLC are listed. The formal names consist of a device type designator, microprocessor designator, and a four-digit unit number. (LEW)

  7. Focusing corner cube

    DOEpatents

    Monjes, J.A.

    1985-09-12

    This invention retortreflects and focuses a beam of light. The invention comprises a modified corner cube reflector wherein one reflective surface is planar, a second reflective surface is spherical, and the third reflective surface may be planar or convex cylindrical.

  8. Final focus test beam

    SciTech Connect

    Not Available

    1991-03-01

    This report discusses the following: the Final Focus Test Beam Project; optical design; magnets; instrumentation; magnetic measurement and BPM calibration; mechanical alignment and stabilization; vacuum system; power supplies; control system; radiation shielding and personnel protection; infrastructure; and administration.

  9. Focus of an Earthquake

    NSDL National Science Digital Library

    McGraw-Hill

    This simple Flash animation by McGraw-Hill shows the relationship between earthquake focus and earthquake epicenter which is found directly above the focus. Also displayed in the animation are the fault plane, fault scarp, and fault trace. The animation is part of a collection of animations and movies related to Physical Geology published by McGraw-Hill. http://highered.mcgraw-hill.com/sites/0072402466/student_view0/chapter16/animations_and_movies.html

  10. Plutonium focus area

    SciTech Connect

    NONE

    1996-08-01

    To ensure research and development programs focus on the most pressing environmental restoration and waste management problems at the U.S. Department of Energy (DOE), the Assistant Secretary for the Office of Environmental Management (EM) established a working group in August 1993 to implement a new approach to research and technology development. As part of this new approach, EM developed a management structure and principles that led to the creation of specific Focus Areas. These organizations were designed to focus the scientific and technical talent throughout DOE and the national scientific community on the major environmental restoration and waste management problems facing DOE. The Focus Area approach provides the framework for intersite cooperation and leveraging of resources on common problems. After the original establishment of five major Focus Areas within the Office of Technology Development (EM-50, now called the Office of Science and Technology), the Nuclear Materials Stabilization Task Group (EM-66) followed the structure already in place in EM-50 and chartered the Plutonium Focus Area (PFA). The following information outlines the scope and mission of the EM, EM-60, and EM-66 organizations as related to the PFA organizational structure.

  11. EDITORIAL: Focus on Plasmonics FOCUS ON PLASMONICS

    NASA Astrophysics Data System (ADS)

    Bozhevolnyi, Sergey; García-Vidal, Francisco

    2008-10-01

    Plasmonics is an emerging field in optics dealing with the so-called surface plasmons whose extraordinary properties are being both analyzed from a fundamental point of view and exploited for numerous technological applications. Surface plasmons associated with surface electron density oscillations decorating metal dielectric interfaces were discovered by Rufus Ritchie in the 1950s. Since the seventies, the subwavelength confinement of electromagnetic fields as well as their enhancement inherent to the surface plasmon excitation has been widely used for spectroscopic purposes. Recent advances in nano-fabrication, characterization and modelling techniques have allowed unique properties of these surface electromagnetic modes to be explored with respect to subwavelength field localization and waveguiding, opening the path to truly nanoscale plasmonic optical devices. This area of investigation also has interesting links with research on photonic band gap materials and the field of optical metamaterials. Nowadays, plasmonics can be seen as a mature interdisciplinary area of research in which scientists coming from different backgrounds (chemistry, physics, optics and engineering) strive to discover and exploit new and exciting phenomena associated with surface plasmons. The already made and forthcoming discoveries will have impacts in many fields of science and technology, including not only photonics and materials science but also computation, biology and medicine, among others. This focus issue of New Journal of Physics is intended to cover all the aforementioned capabilities of surface plasmons by presenting a current overview of state-of-the-art advances achieved by the leading groups in this field of research. Focus on Plasmonics Contents Directional coupling between dielectric and long-range plasmon waveguides Aloyse Degiron, Sang-Yeon Cho, Talmage Tyler, Nan Marie Jokerst and David R Smith Nanoantenna array-induced fluorescence enhancement and reduced lifetimes Reuben M Bakker, Vladimir P Drachev, Zhengtong Liu, Hsiao-Kuan Yuan, Rasmus H Pedersen, Alexandra Boltasseva, Jiji Chen, Joseph Irudayaraj, Alexander V Kildishev and Vladimir M Shalaev Confinement and propagation characteristics of subwavelength plasmonic modes R F Oulton, G Bartal, D F P Pile and X Zhang Theory on the scattering of light and surface plasmon polaritons by arrays of holes and dimples in a metal film F de León-Pérez, G Brucoli, F J García-Vidal and L Martín-Moreno Shaping and manipulation of light fields with bottom-up plasmonic structures C Girard, E Dujardin, G Baffou and R Quidant Gold nanorods and nanospheroids for enhancing spontaneous emission A Mohammadi, V Sandoghdar and M Agio Generation of surface plasmons at single subwavelength slits: from slit to ridge plasmon J-Y Laluet, A Drezet, C Genet and T W Ebbesen Mode mapping of plasmonic stars using TPL microscopy P Ghenuche, S Cherukulappurath and R Quidant Controlling optical transmission through magneto-plasmonic crystals with an external magnetic field G A Wurtz, W Hendren, R Pollard, R Atkinson, L Le Guyader, A Kirilyuk, Th Rasing, I I Smolyaninov and A V Zayats Nanoplasmonic renormalization and enhancement of Coulomb interactions M Durach, A Rusina, V I Klimov and M I Stockman Bulk and surface sensitivities of surface plasmon waveguides Pierre Berini Mapping plasmons in nanoantennas via cathodoluminescence R Gómez-Medina, N Yamamoto, M Nakano and F J García de Abajo Theoretical analysis of gold nano-strip gap plasmon resonators T Søndergaard, J Jung, S I Bozhevolnyi and G Della Valle Surface plasmon polariton-mediated enhancement of the emission of dye molecules on metallic gratings J Gómez Rivas, G Vecchi and V Giannini Nanoshells to nanoeggs to nanocups: optical properties of reduced symmetry core shell nanoparticles beyond the quasistatic limit Mark W Knight and Naomi J Halas Single emitters coupled to plasmonic nano-antennas: angular emission and collection efficiency T H Taminiau, F D Stefani and N F van Hulst Green's tensor calculations of plasmon resonances of single ho

  12. NICMOS focus monitor

    NASA Astrophysics Data System (ADS)

    Schneider, Glenn

    1997-07-01

    This proposal is used to determine and monitor the optimal focus and tilt settings for all three NICMOS cameras. It is derived from SM2/NIC 7041, but is structurally quite a bit different. This proposal is built to run NIC1/2 focus sweeps on a weekly basis, and NIC3 focus sweeps twice a week during SMOV {following the "interim" runs of the 7150}. 7043 will run for as long as it is deemed necessary to keep track of the camera focii and to monitor the dewar anomaly. After the discussion on 20/3/96, this proposal is written to run 4 complete 1-week iterations starting 3 days after the last run of the 7150 {NICMOS COARSE OPTICAL ALIGNMENT, PART 2}.

  13. Tate Online: In Focus

    NSDL National Science Digital Library

    The Tate Gallery in London has received numerous accolades for its fine online educational resources, including archived public presentations and lectures. The In Focus website is yet another one of these types of Internet resources, and allows those with an interest in art to hone in on various subjects in greater detail. By looking through their "In Focus" series, visitors may learn about landscape painting in America, the "pop art" movement of the 1960s, and surrealism. A real treat on the site is the "Works in Focus" section, which allows visitors close and contextual appraisals of a number of modern installations, such as Damien Hirst's provocative "Pharmacy" and that most famous painting, "Ophelia" by John Everett Millais. The Millais feature is also notable as it includes a fine interactive timeline of Millais's life, along with a detailed look at the materials and techniques deployed in the creation of this powerful and popular piece of craftsmanship.

  14. Focus on Efficient Management.

    ERIC Educational Resources Information Center

    Kentucky State Dept. of Education, Frankfort. Office of Resource Management.

    Compiled as a workshop handbook, this guide presents information to help food service program administrators comply with federal regulations and evaluate and upgrade their operations. Part I discusses requirements of the National School Lunch Program, focusing on the "offer versus serve" method of service enacted in 1976 to reduce waste. After an…

  15. Education Policy. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1998

    1998-01-01

    This theme issue includes five articles that focus on educational policy in the Texas legislature in relation to student retention, Internet access, and sexual harassment. "1999 Texas Legislative Session--End of an Era?" (Albert Cortez, Maria Robledo Montecel) examines educational equity issues facing legislators: school funding, including the…

  16. Equity. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1998

    1998-01-01

    This theme issue focuses on equity in children's literature, public funding for private schools, women in educational fields, female dropouts, and the relationship between school violence and family and community violence. "Violence in Our Schools" (Bradley Scott) explores reasons for school violence (media violence, isolation from family, racial…

  17. Public Engagement. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1996

    1996-01-01

    This newsletter includes six articles that examine key issues facing public schools and communities related to accountability, bilingual education, immigrant education, school finance, and school choice. In addressing these issues, articles focus on the importance of community involvement and input in local school reform efforts aimed at achieving…

  18. Policy Update. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1995

    1995-01-01

    This theme issue focuses on the drastic revision of the Texas education code undertaken during the 1995 state legislative session. "Education Policy Reform: Key Points for Districts" (Albert Cortez, Mikki Symonds) outlines critical issues in the legislation that have an impact on educational quality: charter schools exempt from state regulations;…

  19. Instructional Technology. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1997

    1997-01-01

    This theme issue includes five articles that focus on implementing instructional technology in ways that benefit all students, including limited-English-proficient, minority, economically disadvantaged, and at-risk students. "Cruising the Web with English Language Learners" (Laura Chris Green) presents three scenarios using the World Wide Web in…

  20. School Reform. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1998

    1998-01-01

    This theme issue addresses school reform, focusing on accountability, attrition, public-supported private education, equitable education, and schoolwide reform. "School-Student Performance and Accountability" (Jose A. Cardenas) discusses what constitutes good performance in school; the shifting emphasis among the input, output, and process of…

  1. Bilingual Education. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1998

    1998-01-01

    This theme issue focuses on instructional practices, evaluation, and the state of bilingual education. "Effective Implementation of Bilingual Programs: Reflections from the Field" (Abelardo Villarreal, Adela Solis) describes the key characteristics of successful bilingual programs: vision and goals; program leadership; linkage to central office…

  2. Focus: Economic Systems.

    ERIC Educational Resources Information Center

    McCorkle, Sarapage; Meszaros, Bonnie T.; Odorzynski, Sandra J.; Schug, Mark C.; Watts, Michael

    The "Focus" series, part of the National Council on Economic Education's (NCEE) EconomicsAmerica program, uses economics to enhance learning in subjects such as history, geography, civics, and personal finance, as well as economics. Activities are interactive, reflecting the belief that students learn best through active, highly personalized…

  3. Neocortical focus: experimental view.

    PubMed

    Timofeev, Igor; Chauvette, Sylvain; Soltani, Sara

    2014-01-01

    All brain normal or pathological activities occur in one of the states of vigilance: wake, slow-wave sleep, or REM sleep. Neocortical seizures preferentially occur during slow-wave sleep. We provide a description of neuronal behavior and mechanisms mediating such a behavior within neocortex taking place in natural states of vigilance as well as during seizures pointing to similarities and differences exhibited during sleep and seizures. A concept of epileptic focus is described using a model of cortical undercut, because in that model, the borders of the focus are well defined. In this model, as in other models of acquired epilepsy, the main factor altering excitability is deafferentation, which upregulates neuronal excitability that promotes generation of seizures. Periods of disfacilitation recorded during slow-wave sleep further upregulate neuronal excitability. It appears that the state of neurons and neuronal network in the epileptic focus produced by deafferentation are such that seizures cannot be generated there. Instead, seizures always start around the perimeter of the undercut cortex. Therefore, we define these areas as the seizure focus. In this zone, neuronal connectivity and excitability are moderately enhanced, lowering the threshold for seizure generation. PMID:25078497

  4. Focusing educational initiatives

    NASA Technical Reports Server (NTRS)

    Parks, George K.

    1990-01-01

    The United States will soon be facing a critical shortage of aerospace scientists and engineers. To address this problem, Space Grant Colleges can assist in focusing interest in existing educational initiatives and in creating new educational opportunities, particularly for women and underrepresented minorities.

  5. Open focus attention training.

    PubMed

    Fehmi, Lester G; Shor, Susan B

    2013-03-01

    This article describes the role of attention training and brainwave synchrony training in the resolution of stress- and pain-related symptoms. It describes the origin of Open Focus attention training as it was distilled from observations of space-generated brain wave activity. It provides a map of the various attentional styles and associated EEG activity. PMID:23538084

  6. ENC Focus Review.

    ERIC Educational Resources Information Center

    Thorson, Annette, Ed.

    The mission of the Eisenhower National Clearinghouse (ENC) is to identify effective curriculum resources, create high-quality professional development materials, and disseminate useful information and products to improve K-12 mathematics and science teaching and learning. This issue of "ENC Focus" contains articles related to mathematics teaching…

  7. Youth Leadership. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1995

    1995-01-01

    This theme issue focuses on motivating young people to learn by providing leadership opportunities in school. "Coca-Cola Valued Youth Program: Assessing Progress" (Josie Danini Supik) examines the program's success. This program, which trains high-risk middle and high school students as tutors of younger children, has dramatically lowered dropout…

  8. Curriculum Mapping. Focus On

    ERIC Educational Resources Information Center

    Molineaux, Rebecca

    2008-01-01

    This "Focus On" discusses curriculum mapping, a process that allows educators to align the curriculum both within and across grades and to ensure that the curriculum is in line with school, local, and state standards. It outlines the steps of the curriculum mapping process from planning the mapping initiative to creating and editing curriculum…

  9. Focus on Rashomon.

    ERIC Educational Resources Information Center

    Richie, Donald S., Ed.

    This Film Focus series is a collection of reviews, essays, and commentaries on the Japanese film Rashomon. The plot consists of an attack, a rape, and a robbery, all of which probably occurred during the Middle Ages. Each character relates his own version of what happened, or might have happened, revealing the outward and inner driving forces,…

  10. Focus on Basics, 1997.

    ERIC Educational Resources Information Center

    Focus on Basics, 1997

    1997-01-01

    Together, these four newsletters contain 36 articles devoted to adult literacy research and practice and the relationship between them. The following articles are included: "A Productive Partnership" (Richard J. Murnane, Bob Bickerton); "Welcome to 'Focus on Basics'" (Barbara Garner); "Applying Research on the Last Frontier" (Karen Backlund, Kathy…

  11. Focus Article Electrophysiological models

    E-print Network

    Nelson, Mark E.

    Focus Article Electrophysiological models of neural processing Mark E. Nelson The brain modeling and computer simulation techniques have become essential tools in understanding diverse aspects capabilities of individual neurons lie at the core of these models, with the emphasis shifting upward

  12. Theme: Focus on Teaching.

    ERIC Educational Resources Information Center

    Connors, James J.; And Others

    1996-01-01

    Includes "The More Things Change..." (Connors); "Students--Bored of Education?" (Earle); "Yesterday, Today and Tomorrow" (Wesch et al.); "Attitude and the Value of Environment" (Foster); "Fins, Feathers and Fur" (Crank); "Greenhouse as a Focus for Agriscience" (Hurst); and "Agricultural and Environmental Education at Milton Hershey School"…

  13. Focus on First Graders.

    ERIC Educational Resources Information Center

    Schwartz, Shari S.

    The result of a collaboration between the El Paso, Texas, school district and community agencies, the Focus on First Graders program provides early intervention and prevention using a comprehensive approach to providing a variety of services at the school to at-risk first graders from low income families. Teachers and parents were surveyed to…

  14. Focusing on the Invisible

    ERIC Educational Resources Information Center

    Haley, Tim R.

    2008-01-01

    This article seeks to answer the question of whether or not the design and development of an educational laboratory really changes when the focus is on nanotechnology. It explores current laboratory building trends and the added considerations for building a nanotechnology laboratory. The author leaves the reader with additional points to consider…

  15. Focus: DNA probes

    SciTech Connect

    Not Available

    1986-11-01

    Progress in the development of DNA probes for the identification and quantitation of specific genetic sequences in biological samples is reviewed. Current research efforts in the development of DNA probes for the diagnosis of a wide variety of bacterial, viral, and other infectious diseases, such as herpes simplex and cytomegalovirus, and inherited genetic diseases such as cystic fibrosis and sickle cell anemia are discussed. Progress in development of DNA probe assays for cancer diagnosis, detection of Salmonella food poisoning, tissue typing (detection of histocompatibility antigens), mutagen screening, and animal diseases, among other applications is included.

  16. Comparative study of temperature measurements in ex vivo swine muscle and a tissue-mimicking material during high intensity focused ultrasound exposures

    NASA Astrophysics Data System (ADS)

    Maruvada, S.; Liu, Y.; Pritchard, W. F.; Herman, B. A.; Harris, G. R.

    2012-01-01

    Tissue-mimicking materials (TMMs) can provide a convenient, stable, and reproducible means for testing high intensity focused ultrasound (HIFU) devices. When TMMs containing thermal sensors are used to measure ultrasound-induced temperature rise, it is important that measurement results reasonably represent those that occur in biological tissue. Therefore the aim of this paper is to compare the thermal behavior of the TMM under HIFU exposure to that of ex vivo tissue. This was accomplished using both a previously developed TMM and fresh ex vivo swine muscle that were instrumented with bare 50 µm thin wire thermocouples. HIFU at 825 kHz was focused at the thermocouple junction. 30 s exposures of increasing peak negative pressure (1 to 5 MPa) were applied and the temperature profile during and after sonication was recorded. B-mode imaging was used to monitor bubble activity during sonication. If bubble formation was noted during the sonication, the sonication was repeated at the same pressure levels two more times at 20 min intervals. Temperature traces obtained at various pressure levels demonstrated similar types of heating profiles in both the tissue and TMM, the exact nature of which depended on whether bubbles formed during the HIFU exposure. The onset of bubble activity occurred at lower ultrasonic pressures in the TMM, but the basic temperature rise features due to HIFU exposure were essentially the same for both materials.

  17. Focused ion beam system

    DOEpatents

    Leung, Ka-Ngo (Hercules, CA); Gough, Richard A. (Kensington, CA); Ji, Qing (Berkeley, CA); Lee, Yung-Hee Yvette (Berkeley, CA)

    1999-01-01

    A focused ion beam (FIB) system produces a final beam spot size down to 0.1 .mu.m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 .mu.m or less.

  18. Focused ion beam system

    DOEpatents

    Leung, K.; Gough, R.A.; Ji, Q.; Lee, Y.Y.

    1999-08-31

    A focused ion beam (FIB) system produces a final beam spot size down to 0.1 {mu}m or less and an ion beam output current on the order of microamps. The FIB system increases ion source brightness by properly configuring the first (plasma) and second (extraction) electrodes. The first electrode is configured to have a high aperture diameter to electrode thickness aspect ratio. Additional accelerator and focusing electrodes are used to produce the final beam. As few as five electrodes can be used, providing a very compact FIB system with a length down to only 20 mm. Multibeamlet arrangements with a single ion source can be produced to increase throughput. The FIB system can be used for nanolithography and doping applications for fabrication of semiconductor devices with minimum feature sizes of 0.1 m or less. 13 figs.

  19. Microwave spherical focusing systems

    Microsoft Academic Search

    S. S. Vinogradov

    2007-01-01

    Microwave focusing systems of spherical shape (constant K-lens, Luneberg lens and spherical reflector antenna) are investigated. The corresponding wave scattering problems are treated as classical boundary value problems for Maxwell's equations. The systems are illuminated by an electromagnetic plane wave (receiving) and by a complex-point huy-gens source producing a Gaussian beam-like radiation (transmitting). In the case of a spherical lens

  20. Focus Issue: Drug Discovery

    NSDL National Science Digital Library

    Nancy R. Gough (American Association for the Advancement of Science; Science's STKE REV)

    2005-08-02

    This week’s issues of Science and Science’s STKE focus on issues related to the development of therapeutics, including new methods for identifying drug targets and the goal of personalized medicine based on an individual's genetics. STKE specifically looks at the roles the RNAi can play in the drug target identification process, how understanding the genetics behind disease can lead to new options for therapeutic intervention, and how analysis of the signaling network may provide insight for personalized medicine.

  1. Globalization in Focus

    NSDL National Science Digital Library

    2001-01-01

    This site comes to the Web courtesy of Foreign Policy in Focus (FPIF, see the September 8, 1998 Scout Report for Social Sciences). Here users will find a more critical look at the WTO as well as the World Bank and the International Monetary Fund (IMF). FPIF here collects links to articles, event announcements, reports, and other resources. Be sure to scroll down the page to see all of the offerings.

  2. Focus Issue: Plant Communication

    NSDL National Science Digital Library

    Nancy R. Gough (American Association for the Advancement of Science; Science's STKE REV)

    2006-02-14

    This week’s issues of Science and Science’s STKE focus on plant signaling with an emphasis on volatile organic compounds. Science emphasizes the chemistry of and information encoded by plant volatiles and how plants, plant pathogens, or humans utilize this aromatic information. Articles and resources at STKE highlight the evolution of olfactory signal transduction, describe the biosynthetic and signaling pathways of the plant hormone jasmonate, and provide an animated overview of how the plant hormone auxin regulates gene expression.

  3. Asking questions with focus

    NASA Astrophysics Data System (ADS)

    Liu, Fang; Xu, Yi

    2001-05-01

    This study investigates how different interrogative meanings interact with focus in determining the overall F0 profile of a question. We recorded eight native speakers of Mandarin producing statements, yes-no questions with and without a question particle, wh questions, incredulous questions, and confirmation questions. In each sentence, either the initial, medial, final, or no word was focused. The tonal components of the sentences are all high, all rising, all low, or all falling. F0 contours were extracted by measuring every complete vocal period in the initial, medial, and final disyllabic words in each sentence. Preliminary results show that in both statements and questions, the pitch range of the focused words is expanded and that of the postfocus words suppressed (compressed and lowered). However, postfocus pitch-range suppression seems less extensive in questions than in statements, and in some question types than in others. Finally, an extra F0 rise is often observed in the final syllable of a question unless the syllable is the question particle which has the neutral tone. This is indicative of a high or rising boundary tone associated with the interrogative meaning, which seems to be superimposed on the tone of the sentence-final syllable. [Work supported by NIDCD DC03902.

  4. Focus Issue: Measurement on a Small Scale

    NSDL National Science Digital Library

    Nancy R. Gough (American Association for the Advancement of Science; Managing Editor of Science's STKE REV)

    2006-03-21

    This week’s issues of Science and Science’s STKE focus on how instrumentation is advancing investigation of biological questions. Science highlights how advances in detection methods are revealing the chemical aspects of biology, and STKE addresses techniques for single-molecule tracking and approaches to better understanding the interaction of cells with nanoparticles.

  5. Flux focusing eddy current probe

    NASA Technical Reports Server (NTRS)

    Simpson, John W. (Inventor); Clendenin, C. Gerald (Inventor); Fulton, James P. (Inventor); Wincheski, Russell A. (Inventor); Todhunter, Ronald G. (Inventor); Namkung, Min (Inventor); Nath, Shridhar C. (Inventor)

    1997-01-01

    A flux-focusing electromagnetic sensor which uses a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks and material loss in high conductivity material. The unique feature of the device is the ferrous shield isolating a high-turn pick-up coil from an excitation coil. The use of the magnetic shield is shown to produce a null voltage output across the receiving coil in the presence of an unflawed sample. A redistribution of the current flow in the sample caused by the presence of flaws, however, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal. The maximum sensor output is obtained when positioned symmetrically above the crack. Hence, by obtaining the position of the maximum sensor output, it is possible to track the fault and locate the area surrounding its tip. The accuracy of tip location is enhanced by two unique features of the sensor; a very high signal-to-noise ratio of the probe's output which results in an extremely smooth signal peak across the fault, and a rapidly decaying sensor output outside a small area surrounding the crack tip which enables the region for searching to be clearly defined. Under low frequency operation, material thinning due to corrosion damage causes an incomplete shielding of the pick-up coil. The low frequency output voltage of the probe is therefore a direct indicator of the thickness of the test sample.

  6. Development of Nanometer Resolution Focus Detector in Vacuum for Extreme Ultraviolet Microscope

    NASA Astrophysics Data System (ADS)

    Tanaka, Yuzuru; Watanabe, Takeo; Hamamoto, Kazuhiro; Kinoshita, Hiroo

    2006-09-01

    We have developed a focus detection system for an extreme ultraviolet (EUV) mask inspection system with a high numerical aperture (NA) of 0.3. This system operates in a vacuum environment and needs a high resolution for focus detection, because the depth of focus (DOF) of optics with 0.3 NA becomes ± 100 nm or less. The focus detection system of the glancing-incidence type developed consists of a laser diode, a focusing lens, pinholes, and a dual-segmented photodiode. We achieved a focus sensor resolution of less than 20 nm. Furthermore, using our focus detection system, a vacuum pressure of 1× 10-5 Pa was achieved.

  7. SecurityFocus

    NSDL National Science Digital Library

    This news service from SecurityFocus is an excellent resource to learn about important computer security warnings and alerts. The Web site keeps track of many widely used software applications, while reporting known vulnerabilities as they are found. Viruses and worms are another key topic that receives significant attention. Several columns offer expert advice and tips to efficiently use and understand software for different platforms. Government security is covered in the news section, discussing federal practices and legislation related to the national network infrastructure. Because the articles have such a broad scope, the material can be useful for both home and business users.

  8. Physical Review Focus

    NSDL National Science Digital Library

    An online service from the American Physical Society (APS) (mentioned in the September 30, 1994 issue of the Scout Report), Physical Review Focus publishes selective research papers from Physical Review Letters (PRL) to provide "educational value and intrinsic interest to non-specialists" and physicists. Each story is accompanied by a link to the research paper abstract in PRL while subscribers (membership is not free) to PRL online have access to the full-text article. In addition, links to Physical News Update and Physics News Preview from the American Institute of Physics are also provided. Users have access to articles published since March 1998.

  9. Obesity in focus.

    PubMed

    Pavlik, V; Fajfrova, J

    2011-01-01

    Obesity has become the most frequent metabolic disease as a result of life conditions and lifestyle which have resulted in a positive energetic balance. However, at the end of the 20th century it reached the dimension of the global epidemic as a result of constantly increasing energy intake without an adequate increase in energy expenditure. The article describes the 11th International Congress on Obesity which took place in Stockholm in July 2010. The delegates discussed recommended diagnostics and treatments in obesitology. A large number of presentations were focused on nutrition and dietary management. The Congress showed that it is necessary to keep paying obesity due attention. PMID:21452768

  10. Focus in Ecuadorian Quechua

    E-print Network

    Shireman, Joshua

    2012-12-11

    ), the adverb utkata, “quickly,” is unfocused. In (4), it is focused. (3) njuka utkata at?ku-ta kati-rka-ni. 1sg quickly dog-ACC chase-PAST-1sg “I quickly chased the dog.” (4) njuka utkata-mi at?ku-ta kati-rka-ni. 1sg quickly-FOC dog...-ACC chase-PAST-1sg “I quickly chased the dog.” 1 I would like to acknowledge our Quechua consultant Rosa-Maria Masaquiza along with Dr. Harold Torrence and our Field Methods class in the spring...

  11. Transverse field focused system

    DOEpatents

    Anderson, Oscar A. (Berkeley, CA)

    1986-01-01

    A transverse field focused (TFF) system for transport or acceleration of an intense sheet beam of negative ions in which a serial arrangement of a plurality of pairs of concentric cylindrical-arc electrodes is provided. Acceleration of the sheet beam can be achieved by progressively increasing the mean electrode voltage of successive electrode pairs. Because the beam is curved by the electrodes, the system can be designed to transport the beam through a maze passage which is baffled to prevent line of sight therethrough. Edge containment of the beam can be achieved by shaping the side edges of the electrodes to produce an electric force vector directed inwardly from the electrode edges.

  12. Dielectrophoretic columnar focusing device

    DOEpatents

    James, Conrad D. (Albuquerque, NM); Galambos, Paul C. (Albuquerque, NM); Derzon, Mark S. (Tijeras, NM)

    2010-05-11

    A dielectrophoretic columnar focusing device uses interdigitated microelectrodes to provide a spatially non-uniform electric field in a fluid that generates a dipole within particles in the fluid. The electric field causes the particles to either be attracted to or repelled from regions where the electric field gradient is large, depending on whether the particles are more or less polarizable than the fluid. The particles can thereby be forced into well defined stable paths along the interdigitated microelectrodes. The device can be used for flow cytometry, particle control, and other process applications, including cell counting or other types of particle counting, and for separations in material control.

  13. Laser focusing of particle beams

    SciTech Connect

    Channell, P.J.; Elliott, C.J. (Los Alamos National Lab., NM (United States)); Fontana, J.R. (California Univ., Santa Barbara, CA (United States). Dept. of Electrical and Computer Engineering)

    1991-01-01

    We propose a scheme using the Inverse Cerenkov effect to focus particle beams with the potential of high focusing gradients ({approximately}200 kG/cm) and rapid, accurate control of the focusing element. 6 refs.

  14. Isoelectric focusing in space

    NASA Technical Reports Server (NTRS)

    Bier, M.; Egen, N. B.; Mosher, R. A.; Twitty, G. E.

    1982-01-01

    The potential of space electrophoresis is conditioned by the fact that all electrophoretic techniques require the suppression of gravity-caused convection. Isoelectric focusing (IEF) is a powerful variant of electrophoresis, in which amphoteric substances are separated in a pH gradient according to their isoelectric points. A new apparatus for large scale IEF, utilizing a recycling principle, has been developed. In the ground-based prototype, laminar flow is provided by a series of parallel filter elements. The operation of the apparatus is monitored by an automated array of pH and ultraviolet absorption sensors under control of a desk-top computer. The apparatus has proven to be useful for the purification of a variety of enzymes, snake venom proteins, peptide hormones, and other biologicals, including interferon produced by genetic engineering techniques. In planning for a possible space apparatus, a crucial question regarding electroosmosis needs to be addressed To solve this problem, simple focusing test modules are planned for inclusion in an early Shuttle flight.

  15. Retroreflection Focusing Schlieren System

    NASA Technical Reports Server (NTRS)

    Heineck, James T. (Inventor)

    1996-01-01

    A retroreflective type focusing schlieren system which permits the light source to be positioned on the optic side of the system is introduced. The system includes an extended light source, as opposed to a point source, located adjacent to a beam splitter which projects light through the flow field onto a reflecting grating in the form of a grid which generates sheets of light that are directed back through the flow field and the beam splitter onto a primary lens behind which is located a cut-off grid having a grid pattern which corresponds to the grid pattern of the reflecting grating. The cut-off grid is adjustably positioned behind the primary lens and an image plane for imaging the turbulence is adjustably located behind the cut-off grid.

  16. [Transference focused psychotherapy].

    PubMed

    Yeomans, Frank; Delaney, Jill C; Renaud, André

    2007-01-01

    Transference focused psychotherapy is a version of psychodynamic psychotherapy that is modified and specialized for patients with borderline personality disorder. It is based on psychoanalytic principles with an emphasis on object relations theory. A fundamental concept in this model is that the organization of an individual's psyche is structured around internalized versions of interpersonal relations. The relationship experiences that are internalized involve a specific representation of the self, a specific representation of the other (the object of the libidinal or aggressive drive) and an intense affect that links them. However, this movement toward integration of the internal representational world does not take place in individuals with borderline personality, who continue to experience life in a way that is based on rigid and extreme views of self and others. The goal of transference focused psychotherapy is to help individuals advance to an integrated internal world through the analysis of the patient's ongoing experience of his or her relationship with the therapist. It is assumed that the analysis of this relationship will bring to light the internal representations of self and other, and the corresponding affects, that are related to unconscious desires and motivations, and that underlie the individual's extreme and discontinuous experience in life. The therapy begins with a specific diagnostic interview and the establishment of a treatment contract with the patient before the psychotherapeutic work begins. The first goal of the therapy is to engage the patient in the process of observing and gaining awareness of the representations of self and other that guide his or her perceptions of the world. The therapy then helps the patient to understand the internal forces that have kept theses representations segregated from each other and to integrate them into a more mature and coherent sense of self and others. PMID:18253659

  17. Focusing on customer service.

    PubMed

    1996-01-01

    This booklet is devoted to a consideration of how good customer service in family planning programs can generate demand for products and services, bring customers back, and reduce costs. Customer service is defined as increasing client satisfaction through continuous concern for client preferences, staff accountability to clients, and respect for the rights of clients. Issues discussed include the introduction of a customer service approach and gaining staff commitment. The experience of PROSALUD in Bolivia in recruiting appropriate staff, supervising staff, soliciting client feedback, and marketing services is offered as an example of a successful customer service approach. The key customer service functions are described as 1) establishing a welcoming atmosphere, 2) streamlining client flow, 3) personalizing client services, and 4) organizing and providing clear information to clients. The role of the manager in developing procedures is explored, and the COPE (Client-Oriented Provider-Efficient) process is presented as a good way to begin to make improvements. Techniques in staff training in customer service include brainstorming, role playing, using case studies (examples of which are provided), and engaging in practice sessions. Training also leads to the development of effective customer service attitudes, and the differences between these and organizational/staff-focused attitudes are illustrated in a chart. The use of communication skills (asking open-ended questions, helping clients express their concerns, engaging in active listening, and handling difficult situations) is considered. Good recovery skills are important when things go wrong. Gathering and using client feedback is the next topic considered. This involves identifying, recording, and discussing customer service issues as well as taking action on these issues and evaluating the results. The booklet ends by providing a sample of customer service indicators, considering the maintenance of a customer service focus, and reporting comments from the reviewers of the booklet. PMID:12320174

  18. Isoelectric focusing of proteins and peptides

    NASA Technical Reports Server (NTRS)

    Egen, N.

    1979-01-01

    Egg-white solution was chosen as the reference solution in order to assess the effects of operational parameters (voltage, flow rate, ampholine pH range and concentration, and protein concentration) of the RIEF apparatus on protein resolution. Topics of discussion include: (1) comparison of RIEF apparatus to conventional IEF techniques (column and PAG) with respect to resolution and throughput; (2) peptide and protein separation (AHF, Thymosin - Fraction 5, vasoactive peptide, L-asparaginase and ACP); and (3) detection of peptides - dansyl derivatives of amino acids and peptides, post-focusing fluorescent labeling of amino acids, peptides and proteins, and ampholine extraction from focused gels.

  19. COMPRENDO: Focus and approach.

    PubMed

    Schulte-Oehlmann, Ulrike; Albanis, Triantafyllos; Allera, Axel; Bachmann, Jean; Berntsson, Pia; Beresford, Nicola; Carnevali, Daniela Candia; Ciceri, Francesca; Dagnac, Thierry; Falandysz, Jerzy; Galassi, Silvana; Hala, David; Janer, Gemma; Jeannot, Roger; Jobling, Susan; King, Isabella; Klingmüller, Dietrich; Kloas, Werner; Kusk, Kresten Ole; Levada, Ramon; Lo, Susan; Lutz, Ilka; Oehlmann, Jörg; Oredsson, Stina; Porte, Cinta; Rand-Weaver, Marian; Sakkas, Vasilis; Sugni, Michela; Tyler, Charles; van Aerle, Ronny; van Ballegoy, Christoph; Wollenberger, Leah

    2006-04-01

    Tens of thousands of man-made chemicals are in regular use and discharged into the environment. Many of them are known to interfere with the hormonal systems in humans and wildlife. Given the complexity of endocrine systems, there are many ways in which endocrine-disrupting chemicals (EDCs) can affect the body's signaling system, and this makes unraveling the mechanisms of action of these chemicals difficult. A major concern is that some of these EDCs appear to be biologically active at extremely low concentrations. There is growing evidence to indicate that the guiding principle of traditional toxicology that "the dose makes the poison" may not always be the case because some EDCs do not induce the classical dose-response relationships. The European Union project COMPRENDO (Comparative Research on Endocrine Disrupters--Phylogenetic Approach and Common Principles focussing on Androgenic/Antiandrogenic Compounds) therefore aims to develop an understanding of potential health problems posed by androgenic and antiandrogenic compounds (AACs) to wildlife and humans by focusing on the commonalities and differences in responses to AACs across the animal kingdom (from invertebrates to vertebrates) . PMID:16818253

  20. EDITORIAL: Focus on Graphene

    NASA Astrophysics Data System (ADS)

    Peres, N. M. R.; Ribeiro, Ricardo M.

    2009-09-01

    Graphene physics is currently one of the most active research areas in condensed matter physics. Countless theoretical and experimental studies have already been performed, targeting electronic, magnetic, thermal, optical, structural and vibrational properties. Also, studies that modify pristine graphene, aiming at finding new physics and possible new applications, have been considered. These include patterning nanoribbons and quantum dots, exposing graphene's surface to different chemical species, studying multilayer systems, and inducing strain and curvature (modifying in this way graphene's electronic properties). This focus issue includes many of the latest developments on graphene research. Focus on Graphene Contents Electronic properties of graphene and graphene nanoribbons with 'pseudo-Rashba' spin-orbit coupling Tobias Stauber and John Schliemann Strained graphene: tight-binding and density functional calculations R M Ribeiro, Vitor M Pereira, N M R Peres, P R Briddon and A H Castro Neto The effect of sublattice symmetry breaking on the electronic properties of doped graphene A Qaiumzadeh and R Asgari Interfaces within graphene nanoribbons J Wurm, M Wimmer, I Adagideli, K Richter and H U Baranger Weak localization and transport gap in graphene antidot lattices J Eroms and D Weiss Electronic properties of graphene antidot lattices J A Fürst, J G Pedersen, C Flindt, N A Mortensen, M Brandbyge, T G Pedersen and A-P Jauho Splitting of critical energies in the n=0 Landau level of graphene Ana L C Pereira Double-gated graphene-based devices S Russo, M F Craciun, M Yamamoto, S Tarucha and A F Morpurgo Pinning and switching of magnetic moments in bilayer graphene Eduardo V Castro, M P López-Sancho and M A H Vozmediano Electronic transport properties of graphene nanoribbons Katsunori Wakabayashi, Yositake Takane, Masayuki Yamamoto and Manfred Sigrist Many-body effects on out-of-plane phonons in graphene J González and E Perfetto Graphene zigzag ribbons, square lattice models and quantum spin chains Mahdi Zarea and Nancy Sandler On the universal ac optical background in graphene V P Gusynin, S G Sharapov and J P Carbotte Heat conduction in graphene: experimental study and theoretical interpretation S Ghosh, D L Nika, E P Pokatilov and A A Balandin Calculation of the Raman G peak intensity in monolayer graphene: role of Ward identities D M Basko Electronic transport in bilayer graphene Mikito Koshino Magnetic Kronig-Penney model for Dirac electrons in single-layer graphene M Ramezani Masir, P Vasilopoulos and F M Peeters Electrical transport in high-quality graphene pnp junctions Jairo Velasco Jr, Gang Liu, Wenzhong Bao and Chun Ning Lau Local density of states and scanning tunneling currents in graphene N M R Peres, Ling Yang and Shan-Wen Tsai Gaps and tails in graphene and graphane B Dóra and K Ziegler Quasi-ferromagnet spintronics in the graphene nanodisc-lead system Motohiko Ezawa Range and correlation effects in edge disordered graphene nanoribbons Alessandro Cresti and Stephan Roche Remarks on the tight-binding model of graphene Cristina Bena and Gilles Montambaux

  1. A study on the flip angle for an optimal T1-weighted image based on the 3D-THRIVE MRI technique: Focusing on the detection of a hepatocellular carcinoma (HCC)

    NASA Astrophysics Data System (ADS)

    Dong, Kyung-Rae; Goo, Eun-Hoe; Lee, Jae-Seung; Chung, Woon-Kwan; Kim, Young-Jae

    2014-04-01

    This study examined the optimal flip angle (FA) for a T1-weighted image in the detection of a hepatocellular carcinoma (HCC). A 3D-T1-weighted high-resolution isotropic volume examination (THRIVE) technique was used to determine the dependence of the signal to noise ratio (SNR) and the contrast-to-noise ratio (CNR) on the change in FA. This study targeted 40 liver cancer patients (25 men and 15 women aged 50 to 70 years with a mean age of 60.32 ± 6.2 years) who visited this hospital to undergo an abdominal MRI examination from January to June 2013. A 3.0 Tesla MRI machine (Philips, Medical System, Achieva) and a MRI receiver coil for data reception with a 16-channel multicoil were used in this study. The THRIVE (repetition time (TR): 8.1 ms, echo time (TE): 3.7 ms, matrix: 172 × 172, slice thickness: 4 mm, gap: 2 mm, field of view (FOV): 350 mm, and band width (BW): 380.1 Hz) technique was applied as a pulse sequence. The time required for the examination was 19 seconds, and the breath-hold technique was used. Axial images were obtained at five FAs: 5, 10, 15, 20 and 25°. The signal intensities of the liver, the lesion and the background noise were measured based on the acquired images before the SNR and the CNR were calculated. To evaluate the image at the FA, we used SPSS for Windows ver. 17.0 to conduct a one-way ANOVA test. A Bonferroni test was conducted as a post-hoc test. The SNRs of the hemorrhagic HCC in the 3D-THRIVE technique were 35.50 ± 4.12, 97.00 ± 10.24, 66.09 ± 7.29, 53.84 ± 5.43, and 42.92 ± 5.11 for FAs of 5, 10, 15, 20, and 25°, respectively (p = 0.0430), whereas the corresponding CNRs were 30.50 ± 3.84, 43.00 ± 5.42, 36.54 ± 4.09, 32.30 ± 2.79, and 31.69 ± 3.21 (p = 0.0003). At a small FA of 10, the SNR and the CNR showed the highest values. As the FA was increased, the SNR and the CNR values showed a decreasing tendency. In conclusion, the optimal T1-weighted image FA should be set to 10° to detect a HCC by using the 3D-THRIVE abdominal MRI technique.

  2. Frequency-dependent ultrasound-induced transformation in E. coli.

    PubMed

    Deeks, Jeremy; Windmill, James; Agbeze-Onuma, Maduka; Kalin, Robert M; Argondizza, Peter; Knapp, Charles W

    2014-12-01

    Ultrasound-enhanced gene transfer (UEGT) is continuing to gain interest across many disciplines; however, very few studies investigate UEGT efficiency across a range of frequencies. Using a variable frequency generator, UEGT was tested in E. coli at six ultrasonic frequencies. Results indicate frequency can significantly influence UEGT efficiency positively and negatively. A frequency of 61 kHz improved UEGT efficiency by ~70 % higher, but 99 kHz impeded UEGT to an extent worse than no ultrasound exposure. The other four frequencies (26, 133, 174, and 190 kHz) enhanced transformation compared to no ultrasound, but efficiencies did not vary. The influence of frequency on UEGT efficiency was observed across a range of operating frequencies. It is plausible that frequency-dependent dynamics of mechanical and chemical energies released during cavitational-bubble collapse (CBC) are responsible for observed UEGT efficiencies. PMID:25048242

  3. Ultrasound-induced acoustophoretic motion of microparticles in three dimensions

    E-print Network

    Muller, Peter B; Marin, Alvaro G; Barnkob, Rune; Augustsson, Per; Laurell, Thomas; Kaehler, Christian J; Bruus, Henrik

    2013-01-01

    We derive analytical expressions for the three-dimensional (3D) acoustophoretic motion of spherical microparticles in rectangular microchannels. The motion is generated by the acoustic radiation force and the acoustic streaming-induced drag force. In contrast to the classical theory of Rayleigh streaming in shallow, infinite, parallel-plate channels, our theory does include the effect of the microchannel side walls. The resulting predictions agree well with numerics and experimental measurements of the acoustophoretic motion of polystyrene spheres with nominal diameters of 0.537 um and 5.33 um. The 3D particle motion was recorded using astigmatism particle tracking velocimetry under controlled thermal and acoustic conditions in a long, straight, rectangular microchannel actuated in one of its transverse standing ultrasound-wave resonance modes with one or two half-wavelengths. The acoustic energy density is calibrated in situ based on measurements of the radiation dominated motion of large 5-um-diam particles...

  4. Optical monitoring of ultrasound-induced bioeffects in glass catfish

    Microsoft Academic Search

    Subha Maruvada; Kullervo Hynynen

    2004-01-01

    This study is an investigation of the therapeutic ultrasound (US) effects on the blood vessels of optically transparent fish in vivo. Although many investigators have characterized cavitation in vivo using remote-sensing methods (i.e., measuring the acoustic emissions caused by oscillating bubbles) very few have made direct observations of cavitation-induced damage. Anesthetized glass catfish, which are optically transparent, was injected with

  5. Cable Diagnostic Focused Initiative

    SciTech Connect

    Hartlein, R.A.; Hampton, R.N.

    2010-12-30

    This report summarizes an extensive effort made to understand how to effectively use the various diagnostic technologies to establish the condition of medium voltage underground cable circuits. These circuits make up an extensive portion of the electric delivery infrastructure in the United States. Much of this infrastructure is old and experiencing unacceptable failure rates. By deploying efficient diagnostic testing programs, electric utilities can replace or repair circuits that are about to fail, providing an optimal approach to improving electric system reliability. This is an intrinsically complex topic. Underground cable systems are not homogeneous. Cable circuits often contain multiple branches with different cable designs and a range of insulation materials. In addition, each insulation material ages differently as a function of time, temperature and operating environment. To complicate matters further, there are a wide variety of diagnostic technologies available for assessing the condition of cable circuits with a diversity of claims about the effectiveness of each approach. As a result, the benefits of deploying cable diagnostic testing programs have been difficult to establish, leading many utilities to avoid the their use altogether. This project was designed to help address these issues. The information provided is the result of a collaborative effort between Georgia Tech NEETRAC staff, Georgia Tech academic faculty, electric utility industry participants, as well as cable system diagnostic testing service providers and test equipment providers. Report topics include: •How cable systems age and fail, •The various technologies available for detecting potential failure sites, •The advantages and disadvantages of different diagnostic technologies, •Different approaches for utilities to employ cable system diagnostics. The primary deliverables of this project are this report, a Cable Diagnostic Handbook (a subset of this report) and an online knowledge based system (KBS) that helps utilities select the most effective diagnostic technologies for a given cable circuit and circuit conditions.

  6. Suprathermal microwave emission from the plasma focus

    Microsoft Academic Search

    G. Herziger; H. Krompholz; L. Michel; K. Schoenbach

    1977-01-01

    Time-resolved microwave measurements were performed at a 1 kG plasma focus. Radiation within the frequency ranges (0.26-1.8) times 10 to the 10th power Hz and (2.65-4.0) times 10 to the 10th power Hz was detected along with a two-peak soft X-ray pulse at pinch. The maximum output of the lower frequency radiation corresponded in time to the first peak in

  7. Hydrodynamic focusing – a versatile tool

    PubMed Central

    Golden, Joel P.; Justin, Gusphyl A.; Nasir, Mansoor; Ligler, Frances S.

    2011-01-01

    The control of hydrodynamic focusing in a microchannel has inspired new approaches for microfluidic mixing, separations, sensors, cell analysis and microfabrication. Achieving a flat interface between the focusing and focused fluids is dependent on Reynolds number and device geometry, and many hydrodynamic focusing systems can benefit from this understanding. For applications where a specific cross-sectional shape is desired for the focused flow, advection generated by grooved structures in the channel walls can be used to define the shape of the focused flow. Relative flow rates of the focused flow and focusing streams can be manipulated to control the crosssectional area of the focused flows. This manuscript discusses the principles for defining the shape of the interface between the focused and focusing fluids and provides examples from our lab that use hydrodynamic focusing for impedance-based sensors, flow cytometry, and microfabrication to illustrate the breadth of opportunities for introducing new capabilities into microfluidic systems. We evaluate each example for the advantages and limitations integral to utilization of hydrodynamic focusing for that particular application. PMID:21952728

  8. Range from focus-error

    Microsoft Academic Search

    M. W. Siegel; M. L. Leary

    We derive theoretically and demonstrate experimentally an approach to range-from-focus with an important improvement over all previous methods. Previous methods rely on subjective measures of sharpness to focus a selected locale of the image. Our method uses measured physical features of the optical signal to generate an objective focus-error distance map. To compute range-from-focus-error distance it is not necessary to

  9. AADD-FOCUSED Mailing List

    NSDL National Science Digital Library

    The AADD-FOCUSED mailing list is an unmoderated focused discussion list for adults who have ADD (Attention Deficit Disorder). Although there are other forums available for discussion of ADD-related topics, they are often too broadly defined and receive many postings not having to do with Adult ADD. Therefore AADD-FOCUSED has been created specifically for those who wish to read fewer, more focused messages per day on the subject of Adult ADD.

  10. Focus in graphical user interfaces

    Microsoft Academic Search

    Manuel A. Pérez-Quiñones; John L. Sibert

    1993-01-01

    Focus in natural language processing is used to keep track of the attentional space of the participants in the dialogue. Graphical interfaces have still to benefit from the use of this level of communication. We discuss a graphical interface counter part called a focus space. Focus spaces can be used to combine multiple interaction styles (e.g. natural language with graphical

  11. Focusing Electron Beams at SLAC.

    ERIC Educational Resources Information Center

    Taylor, Richard L.

    1993-01-01

    Describes the development of a set of magnets that focus high-energy electron and positron beams causing them to collide, annihilate each other, and generate new particles. Explains how dipoles bend the beam, how quadrupoles focus the beam, how the focal length is calculated, and the superconducting final focus. (MDH)

  12. EDITORIAL: Focus on Quantum Control

    NASA Astrophysics Data System (ADS)

    Rabitz, Herschel

    2009-10-01

    Control of quantum phenomena has grown from a dream to a burgeoning field encompassing wide-ranging experimental and theoretical activities. Theoretical research in this area primarily concerns identification of the principles for controlling quantum phenomena, the exploration of new experimental applications and the development of associated operational algorithms to guide such experiments. Recent experiments with adaptive feedback control span many applications including selective excitation, wave packet engineering and control in the presence of complex environments. Practical procedures are also being developed to execute real-time feedback control considering the resultant back action on the quantum system. This focus issue includes papers covering many of the latest advances in the field. Focus on Quantum Control Contents Control of quantum phenomena: past, present and future Constantin Brif, Raj Chakrabarti and Herschel Rabitz Biologically inspired molecular machines driven by light. Optimal control of a unidirectional rotor Guillermo Pérez-Hernández, Adam Pelzer, Leticia González and Tamar Seideman Simulating quantum search algorithm using vibronic states of I2 manipulated by optimally designed gate pulses Yukiyoshi Ohtsuki Efficient coherent control by sequences of pulses of finite duration Götz S Uhrig and Stefano Pasini Control by decoherence: weak field control of an excited state objective Gil Katz, Mark A Ratner and Ronnie Kosloff Multi-qubit compensation sequences Y Tomita, J T Merrill and K R Brown Environment-invariant measure of distance between evolutions of an open quantum system Matthew D Grace, Jason Dominy, Robert L Kosut, Constantin Brif and Herschel Rabitz Simplified quantum process tomography M P A Branderhorst, J Nunn, I A Walmsley and R L Kosut Achieving 'perfect' molecular discrimination via coherent control and stimulated emission Stephen D Clow, Uvo C Holscher and Thomas C Weinacht A convenient method to simulate and visually represent two-photon power spectra of arbitrarily and adaptively shaped broadband laser pulses M A Montgomery and N H Damrauer Accurate and efficient implementation of the von Neumann representation for laser pulses with discrete and finite spectra Frank Dimler, Susanne Fechner, Alexander Rodenberg, Tobias Brixner and David J Tannor Coherent strong-field control of multiple states by a single chirped femtosecond laser pulse M Krug, T Bayer, M Wollenhaupt, C Sarpe-Tudoran, T Baumert, S S Ivanov and N V Vitanov Quantum-state measurement of ionic Rydberg wavepackets X Zhang and R R Jones On the paradigm of coherent control: the phase-dependent light-matter interaction in the shaping window Tiago Buckup, Jurgen Hauer and Marcus Motzkus Use of the spatial phase of a focused laser beam to yield mechanistic information about photo-induced chemical reactions V J Barge, Z Hu and R J Gordon Coherent control of multiple vibrational excitations for optimal detection S D McGrane, R J Scharff, M Greenfield and D S Moore Mode selectivity with polarization shaping in the mid-IR David B Strasfeld, Chris T Middleton and Martin T Zanni Laser-guided relativistic quantum dynamics Chengpu Liu, Markus C Kohler, Karen Z Hatsagortsyan, Carsten Muller and Christoph H Keitel Continuous quantum error correction as classical hybrid control Hideo Mabuchi Quantum filter reduction for measurement-feedback control via unsupervised manifold learning Anne E B Nielsen, Asa S Hopkins and Hideo Mabuchi Control of the temporal profile of the local electromagnetic field near metallic nanostructures Ilya Grigorenko and Anatoly Efimov Laser-assisted molecular orientation in gaseous media: new possibilities and applications Dmitry V Zhdanov and Victor N Zadkov Optimization of laser field-free orientation of a state-selected NO molecular sample Arnaud Rouzee, Arjan Gijsbertsen, Omair Ghafur, Ofer M Shir, Thomas Back, Steven Stolte and Marc J J Vrakking Controlling the sense of molecular rotation Sharly Fleischer, Yuri Khodorkovsky, Yehiam Prior and Ilya Sh Averbukh Optimal control of interacting particles: a

  13. Mirror alignment and focus of point-focus solar concentrators

    Microsoft Academic Search

    Richard B. Diver

    1994-01-01

    Distributed point-focusing solar concentrators are being developed for dish-Stirling systems and other applications. Many of these concentrators make use of faceted mirrors that have to be accurately aligned. Some of the solar concentrator designs use stretched-membrane facets that also require focusing. Accurate mirror alignment and focus of faceted solar concentrators have two benefits. First, the concentration ratio of the concentrator\\/receiver

  14. Use of ionic liquid aggregates of 1-hexadecyl-3-butyl imidazolium bromide in a focused-microwave assisted extraction method followed by high-performance liquid chromatography with ultraviolet and fluorescence detection to determine the 15+1 EU priority PAHs in toasted cereals ("gofios").

    PubMed

    Germán-Hernández, Mónica; Pino, Verónica; Anderson, Jared L; Afonso, Ana M

    2011-08-15

    A focused-microwave assisted extraction method using aggregates of the ionic liquid (IL) 1-hexadecyl-3-butylimidazolium bromide (HDBIm-Br) followed by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection and single-channel fluorescence detection (FLD) has been developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in toasted cereals ("gofios") of different nature (wheat, barley, rye, and maize corn) from the Canary Islands, Spain. The optimized HPLC-UV-vis/single-channel FLD method takes 40 min for the chromatographic run with limits of detection varying between 0.02 and 4.01 ng mL(-1) for the fluorescent PAHs from the European Union (EU) priority list in foods, and 20.5 ng mL(-1) for the non-fluorescent PAH cyclopenta[c,d]pyrene (CPP). The optimized microwave step presented extractions recoveries ranging from 70.1 to 109% and precision values lower than 12.6% (as relative standard deviation), using an extraction time of 14 min. The extraction method also utilizes low amounts of sample (0.1g), and low amounts of IL (77 mg), avoiding completely the use of organic solvents. PMID:21726759

  15. Mirror alignment and focus of point-focus solar concentrators

    NASA Astrophysics Data System (ADS)

    Diver, Richard B.

    Distributed point-focusing solar concentrators are being developed for dish-Stirling systems and other applications. Many of these concentrators make use of faceted mirrors that have to be accurately aligned. Some of the solar concentrator designs use stretched-membrane facets that also require focusing. Accurate mirror alignment and focus of faceted solar concentrators have two benefits. First, the concentration ratio of the concentrator/receiver (collector) system is improved with accurate alignment and focus. The receiver aperture diameter can therefore be smaller, thereby reducing thermal losses from the receiver and improving the overall efficiency of the collector. Second, and perhaps more importantly, flux intensities on the receiver can be sensitive to facet alignment and focus. In this paper, the theory and practical application of an alignment and focusing technique are presented. In the technique, light from an artificial source is reflected from the concentrator's facets to a target. From basic geometric principles, the shape and location of the reflected light on the target can be predicted. Alignment is accomplished by adjusting the facets' aim so that the reflected image falls on the predetermined location. To focus a stretched-membrane facet, the reflected image size is adjusted to match that of the target. The governing equations used to draw the alignment targets are developed and the practical application of the technique to the alignment and focus of the Cummins Power Generation, Inc. CPG-460 are presented. Alignment uncertainty associated with this technique on the CPG-460 is also discussed.

  16. Mirror alignment and focus of point-focus solar concentrators

    SciTech Connect

    Diver, R.B.

    1994-11-01

    Distributed point-focusing solar concentrators are being developed for dish-Stirling systems and other applications. Many of these concentrators make use of faceted mirrors that have to be accurately aligned. Some of the solar concentrator designs use stretched-membrane facets that also require focusing. Accurate mirror alignment and focus of faceted solar concentrators have two benefits. First, the concentration ratio of the concentrator/receiver (collector) system is improved with accurate alignment and focus. The receiver aperture diameter can therefore be smaller, thereby reducing thermal losses from the receiver and improving the overall efficiency of the collector. Second, and perhaps more importantly, flux intensities on the receiver can be sensitive to facet alignment and focus. In this paper, the theory and practical application of an alignment and focusing technique are presented. In the technique, light from an artificial source is reflected from the concentrator`s facets to a target. From basic geometric principles, the shape and location of the reflected light on the target can be predicted. Alignment is accomplished by adjusting the facets aim so that the reflected image falls on the predetermined location. To focus a stretched-membrane facet, the reflected image size is adjusted to match that of the target. The governing equations used to draw the alignment targets are developed and the practical application of the technique to the alignment and focus of the Cummins Power Generation, Inc. CPG-460 are presented. Alignment uncertainty associated with this technique on the CPG-460 is also discussed.

  17. Focus On.... Biodiversity and Conservation

    E-print Network

    Miranda, Eduardo Reck

    Focus On.... Biodiversity and Conservation This resource guide aims to provide useful, detailed, high quality sources of information on biodiversity and conservation for students in Higher and Further at http://www.intute.ac.uk/biologicalsciences/ This Focus On... guide is located at: http://www.intute.ac.uk/supportdocs/focuson/biodiversity

  18. Focused ultrasound for early detection of tooth decay

    Microsoft Academic Search

    David A. Hughes; John M. Girkin; Simon Poland; Chris Longbottom; Sandy Cochran

    2009-01-01

    Ultrasound is a well-established tool for medical imaging but it has yet to emerge in routine use in dental diagnostics. Nevertheless, it was shown in the late 1970s that ultrasound can be used to probe the internal structures of teeth, and more recently to observe surface changes due to caries and acid erosion.

  19. Wideband focused transducer array for optoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Simonova, V. A.; Khokhlova, T. D.; Karabutov, A. A.

    2009-11-01

    The calculation procedure of the parameters of a multielement transducer array for the optoacoustic tomography of biological objects with high spatial resolution values is proposed. A multielement transducer with given spatial resolution values in three dimensions has been developed based on the proposed procedure for the early detection of breast cancer. The transducer array consists of a set of 8 linear PVDF piezoelectric films located on a plane and a focusing cylindrical acoustic lens. A map of the transducer’s focal area and point spread function have been measured using the constructed transducer array. Spatial resolutions of the transducer array obtained experimentally are in agreement with their calculated values.

  20. Design of Automatic Focusing Glasses for Presbyopia variable focusing lens

    E-print Network

    Fujita, Toyomi

    -sensitive device (DSD) compound eye miniaturized light source we pro- posed previously .5)The DSD consists of multiple mini- aturized PSDs and lenses (Fig.3). The distance to focus For older persons, decreased visual

  1. Prime focus instrument of prime focus spectrograph for Subaru telescope

    NASA Astrophysics Data System (ADS)

    Wang, Shiang-Yu; Braun, David F.; Schwochert, Mark A.; Huang, Pin-Jie; Kimura, Masahiko; Chen, Hsin-Yo; Reiley, Daniel J.; Mao, Peter; Fisher, Charles D.; Tamura, Naoyuki; Chang, Yin-Chang; Hu, Yen-Sang; Ling, Hung-Hsu; Wen, Chih-Yi; Chou, Richard C.-Y.; Takato, Naruhisa; Sugai, Hajime; Ohyama, Youichi; Karoji, Hiroshi; Shimono, Atsushi; Ueda, Akitoshi

    2014-07-01

    The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph design for the prime focus of the 8.2m Subaru telescope. PFS will cover 1.3 degree diameter field with 2394 fibers to complement the imaging capability of Hyper SuprimeCam (HSC). The prime focus unit of PFS called Prime Focus Instrument (PFI) provides the interface with the top structure of Subaru telescope and also accommodates the optical bench in which Cobra fiber positioners are located. In addition, the acquisition and guiding (AG) cameras, the optical fiber positioner system, the cable wrapper, the fiducial fibers, illuminator, and viewer, the field element, and the telemetry system are located inside the PFI. The mechanical structure of the PFI was designed with special care such that its deflections sufficiently match those of the HSC's Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations within the required accuracy.

  2. Plutonium focus area: Technology summary

    SciTech Connect

    NONE

    1996-03-01

    To ensure research and development programs focus on the most pressing environmental restoration and waste management problems at the U.S. Department of Energy (DOE), the Assistant Secretary for the Office of Environmental Management (EM) established a working group in August 1993 to implement a new approach to research and technology development. As part of this approach, EM developed a management structure and principles that led to creation of specific focus areas. These organizations were designed to focus scientific and technical talent throughout DOE and the national scientific community on major environmental restoration and waste management problems facing DOE. The focus area approach provides the framework for inter-site cooperation and leveraging of resources on common problems. After the original establishment of five major focus areas within the Office of Technology Development (EM-50), the Nuclear Materials Stabilization Task Group (NMSTG, EM-66) followed EM-50`s structure and chartered the Plutonium Focus Area (PFA). NMSTG`s charter to the PFA, described in detail later in this book, plays a major role in meeting the EM-66 commitments to the Defense Nuclear Facilities Safety Board (DNFSB). The PFA is a new program for FY96 and as such, the primary focus of revision 0 of this Technology Summary is an introduction to the Focus Area; its history, development, and management structure, including summaries of selected technologies being developed. Revision 1 to the Plutonium Focus Area Technology Summary is slated to include details on all technologies being developed, and is currently planned for release in August 1996. The following report outlines the scope and mission of the Office of Environmental Management, EM-60, and EM-66 organizations as related to the PFA organizational structure.

  3. Compact electron beam focusing column

    SciTech Connect

    Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani

    2001-07-13

    A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2-D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.

  4. Statistical Mechanics with focus on

    E-print Network

    Johannesson, Henrik

    Statistical Mechanics with focus on Liquids, Solutions and Colloidal Systems Course contents A. Foundations of statistical mechanics Classical dynamics ­ Hamilton's and Liouville's equations The concept thermodynamics and statistical mechanics. B. Liquid state theory; Equilibrium statistical mechanics for liquids

  5. Nature Web Focus: Ocean Genomics

    NSDL National Science Digital Library

    2003-01-01

    The August 28, 2003 issue of the journal Nature presented a collection of reports that, "along with other analysis of key components of the ocean's food web, highlights the significance of genome sequences from the sea." This Web Focus provides access to these reports free of charge to any reader. The reports focus particularly on marine phytoplankton. The site also includes links to related articles from the Nature archives, but viewing these reports requires a paid subscription.

  6. Generalizing Focus+Context Visualization

    Microsoft Academic Search

    Helwig Hauser

    Focus+context visualization is well-known from information visualization: cer- tain data subsets of special interest are shown in more detail (locally enlarged) whereas the rest of the data is provided as context (in reduced space) to sup- port user orientation and navigation. The key point of this work is a generalized denition of focus+context vi- sualization which extends its applicability also

  7. Qualitative research. Introducing focus groups.

    PubMed Central

    Kitzinger, J.

    1995-01-01

    This paper introduces focus group methodology, gives advice on group composition, running the groups, and analysing the results. Focus groups have advantages for researchers in the field of health and medicine: they do not discriminate against people who cannot read or write and they can encourage participation from people reluctant to be interviewed on their own or who feel they have nothing to say. Images p301-a PMID:7633241

  8. Unnatural language detection

    Microsoft Academic Search

    Thomas Lavergne

    2006-01-01

    In the context of web search engines, the escalation between ranking techniques and spamdexing techniques has led to the appearance of faked contents in web pages. If random sequences of keywords are easily detectable, web pages produced by dedicated content genera- tors are a lot more difficult to detect. Motivated by search engines applications, we will focus on the problem

  9. Craters detection on lunar

    Microsoft Academic Search

    Nur Diyana Kamarudin; Siti Noormiza Makhtar; Hizrin Dayana M. Hidzir

    2011-01-01

    This project focuses on identification of craters in terms of its characteristics and detection of these visual features of the moon to determine a safe landing site for a lunar Lander. Cheng et al. proposed using craters as landmarks for navigation purposes because this geometric model grants a robust detection under different lighting conditions. Moreover, craters appear in enough density

  10. Towards Fraud Detection Methodologies

    Microsoft Academic Search

    Tareq Allan; Justin Zhan

    2010-01-01

    Fraud and abuse have led to significant additional expense in the banking and financial system of the United States. This paper aims to provide a comprehensive survey of the statistical methods applied to banking and financial fraud detection, with focuses on classifying fraudulent behaviors, identifying the major sources and characteristics of the data based on which fraud detection has been

  11. Capillary isoelectric focusing of individual mitochondria.

    PubMed

    Wolken, Gregory G; Kostal, Vratislav; Arriaga, Edgar A

    2011-01-15

    Mitochondria are highly heterogeneous organelles that likely have unique isoelectric points (pI), which are related to their surface compositions and could be exploited in their purification and isolation. Previous methods to determine pI of mitochondria report an average pI. This article is the first report of the determination of the isoelectric points of individual mitochondria by capillary isoelectric focusing (cIEF). In this method, mitochondria labeled with the mitochondrial-specific probe 10-N-nonyl acridine orange (NAO) are injected into a fused-silica capillary in a solution of carrier ampholytes at physiological pH and osmolarity, where they are focused then chemically mobilized and detected by laser-induced fluorescence (LIF). Fluorescein-derived pI markers are used as internal standards to assign a pI value to each individually detected mitochondrial event, and a mitochondrial pI distribution is determined. This method provides reproducible distributions of individual mitochondrial pI, accurate determination of the pI of individual mitochondria by the use of internal standards, and resolution of 0.03 pH units between individual mitochondria. This method could also be applied to investigate or design separations of organelle subtypes (e.g., subsarcolemmal and interfibrillar skeletal muscle mitochondria) and to determine the pIs of other biological or nonbiological particles. PMID:21192658

  12. Intrusion detection system elements

    SciTech Connect

    Eaton, M.J.; Mangan, D.L.

    1980-09-01

    This report highlights elements required for an intrusion detection system and discusses problems which can be encountered in attempting to make the elements effective. Topics discussed include: sensors, both for exterior detection and interior detection; alarm assessment systems, with the discussion focused on video assessment; and alarm reporting systems, including alarm communication systems and dislay/console considerations. Guidance on careful planning and design of a new or to-be-improved system is presented.

  13. Experimental Phased Array Focusing in Pipe Using Ultrasonic Guided Waves

    NASA Astrophysics Data System (ADS)

    Gavigan, B. J.; Zhang, L.; Sun, Z.; Rose, J. L.

    2005-04-01

    The phased array focusing technique is being developed with the intent to inspect hundreds of feet of pipeline from a single array position. The single array position is beneficial if access to a pipe is limited, e.g. steam pipes onboard U.S. Naval ships, nuclear power plants, oil and gas pipelines, etc. From a single array position, ultrasonic guided waves propagate down the length of the pipe and return information about potential defects. Focusing the ultrasonic energy at a predetermined location along the length of the pipe enhances the ability to detect defects that current state of the art inspection systems cannot detect. In this paper, theoretical time delays are used to focus torsional ultrasonic guided waves in the frequency ranges of 30 to 130 kHz and 200 to 800 kHz. Results of the focusing experiments are presented along with some concluding remarks and future work.

  14. Multi-focus cluster labeling.

    PubMed

    Eikvil, Line; Jenssen, Tor-Kristian; Holden, Marit

    2015-06-01

    Document collections resulting from searches in the biomedical literature, for instance, in PubMed, are often so large that some organization of the returned information is necessary. Clustering is an efficient tool for organizing search results. To help the user to decide how to continue the search for relevant documents, the content of each cluster can be characterized by a set of representative keywords or cluster labels. As different users may have different interests, it can be desirable with solutions that make it possible to produce labels from a selection of different topical categories. We therefore introduce the concept of multi-focus cluster labeling to give users the possibility to get an overview of the contents through labels from multiple viewpoints. The concept for multi-focus cluster labeling has been established and has been demonstrated on three different document collections. We illustrate that multi-focus visualizations can give an overview of clusters along axes that general labels are not able to convey. The approach is generic and should be applicable to any biomedical (or other) domain with any selection of foci where appropriate focus vocabularies can be established. A user evaluation also indicates that such a multi-focus concept is useful. PMID:25869415

  15. Focused electron beam in pyroelectric electron probe microanalyzer.

    PubMed

    Imashuku, Susumu; Imanishi, Akira; Kawai, Jun

    2013-07-01

    We report a method to focus the electron beam generated using a pyroelectric crystal. An electron beam with a spot size of 100 ?m was achieved by applying an electrical field to an electroconductive needle tip set on a pyroelectric crystal. When the focused electron beam bombarded a sample, characteristic X-rays of the sample were only detected due to the production of an electric field between the needle tip and the sample. PMID:23902048

  16. A continuous plasma final focus

    SciTech Connect

    Whittum, D.H.

    1989-11-01

    Scaling laws are set down for a plasma cell used for transport, focusing and current neutralization of fine, intense, relativistic electron beams. It is found that there exists a minimum beam spot size, {sigma}{sub min} {approximately} {var epsilon}{sub n}(I{sub A}/{gamma}I){sup 1/2}, in such a focusing system. Propagation issues, including channel formation, synchrotron radiation, beam ionization and instabilities, are discussed. Numerical examples are given for a proof-of-principle experiment at KEK, an application for luminosity enhancement at the SLC, and a hypothetical TeV electron-positron collider. For a TeV collider, it is found that the effect of ion-motion on focusing, and the effect of Buneman instability on current neutralization must be considered. 3 figs., 1 tab.

  17. Magnetically focused liquid drop radiator

    NASA Astrophysics Data System (ADS)

    Botts, T. E.; Powell, J. R.; Lenard, R.

    1984-12-01

    A magnetically focused liquid drop radiator for application in rejecting energy from a spacecraft is described. It is characterized by a magnetizable liquid or slurry disposed in operative relationship within the liquid droplet generator and its fluid delivery system, in combination with magnetic means disposed in operative relationship around a liquid droplet collector of the LDR. The magnetic means are effective to focus streams of droplets directed from the generator toward the collector, thereby to assure that essentially all of the droplets are directed into the collector, even though some of the streams may be misdirected as they leave the generator. The magnetic focusing means is also effective to suppress splashing of liquid when the droplets impinge on the collector.

  18. Electronic focusing in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Häberle, Patricio; Hevia, Samuel; Segura, Rodrigo

    2010-03-01

    Slow electrons traveling close to a surface exhibit modifications of their trajectories due to the polarization charge they induce on the surface. This image charge interaction, in the case of carbon nanotubes (CNTs), is responsible for focusing electrons traveling in the vicinity of a nanotube. The consequences of this effect on the electronic trajectories are more significant for both low kinetic energies and small tube diameters. Numerical calculations indicate low energy electron spectroscopies are especially sensitive to this phenomenon. We have observed evidence of this electronic focusing in inverse photoemission spectroscopy from different CNTs samples.

  19. Speeding chemical reactions by focusing

    E-print Network

    A. M. Lacasta; L. Ramirez-Piscina; J. M. Sancho; K. Lindenberg

    2012-12-13

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate (t to the power -1/2) to very close to the perfect mixing rate, (t to the power -1).

  20. Speeding chemical reactions by focusing

    E-print Network

    Lacasta, A M; Sancho, J M; Lindenberg, K

    2012-01-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate (t to the power -1/2) to very close to the perfect mixing rate, (t to the power -1).

  1. Winter 2010 EVENTS FOCUS: RUSSIA

    E-print Network

    Eustice, Ryan

    Winter 2010 EVENTS FOCUS: RUSSIA Tue, Jan 12, 4-5:30 pm WCED/CREES/Ford School Lecture. "U.S.-Russia Relations: Status of the `Reset'." John Beyrle, U.S. Ambassador to Russia. Co-sponsors: International Policy and literature, Oberlin College. Wed, Feb 3, 12-1:30 pm CREES Brown Bag. "Nostalgia in Post-Socialist Russia

  2. Standards and Assessment. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1997

    1997-01-01

    This newsletter includes three articles, two of which focus on standards for student evaluation and for admission to higher education. "A Measuring Stick for Standards and TEKS: Meeting the Needs of Second Language Learners" (Laura Chris Green, Adela Solis) examines beliefs embodied in the notion of standards; defines content, performance, and…

  3. Technology for Education. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1998

    1998-01-01

    This theme issue includes five articles that focus on technology for education to benefit all students, including limited-English-proficient, minority, economically disadvantaged, and at-risk students. "Coca-Cola Valued Youth Program Students Meet Peers Via Video Conference" (Linda Cantu, Leticia Lopez-De La Garza) describes how at-risk student…

  4. REGULATORY FOCUS AND ENTREPRENEURIAL FREEDOM

    Microsoft Academic Search

    Peter Bryant

    Entrepreneurs are typically motivated by a desire for freedom, which is here defined in terms of the acquisition and exercise of capabilities in the pursuit of valued outcomes. At the same time, evidence suggests that entrepreneurs are more strongly motivated by promotion focus, which refers to the fundamental self-regulatory orientation towards positive attainment goals. This theoretical paper unites these two

  5. World History. Focus on Economics.

    ERIC Educational Resources Information Center

    Caldwell, Jean; Clark, James; Herscher, Walter

    This book opens with an exploration of the first economic revolution, which set the stage for the dramatic unfolding of the role economics has played in world history. The lessons focus on two topics: (1) why some economies grew and prospered while others remained stagnant or declined; and (2) what causes people to make choices that help or hinder…

  6. The ionospheric focused heating experiment

    SciTech Connect

    Bernhardt, P.A.; Siefring, C.L.; Rodriguez, P. [Naval Research Lab., Washington, DC (United States)] [and others] [Naval Research Lab., Washington, DC (United States); and others

    1995-09-01

    The Ionospheric Focused Heating rocket was launched on May 30, 1992. The sounding rocket carried an instrument and chemical payload along a trajectory that crossed the intersection of the beams from the 430-MHz incoherent scatter radar and the 5.1-MHz high-power radio wave facility near Arecibo. The release of 30 kg of CF{sub 3}Br into the F region at 285 km altitude produced an ionospheric hole that acted like a convergent lens to focus the HF transmission. The power density inside the radio beam was raised by 12 dB immediately after the release. A wide range of new processes were recorded by in situ and ground-based instruments. Measurements by instruments flying through the modified ionosphere show small-scale microcavities (< 1 m) and downshifted electron plasma (Langmuir) waves inside the artificial cavity, electron density spikes at the edge of the cavity, and Langmuir waves coincident with ion gyroradius (4 m) cavities near the radio wave reflection altitude. The Arecibo incoherent scatter radar showed 20 dB or greater enhancements in ion acoustic and Langmuir wave turbulence after the 5.1-MHz radio beam was focused by the artificial lens. Enhancements in airglow from chemical reactions and, possibly, electron acceleration were recorded with optical instruments. The Ionospheric Focused Heating experiment verified some of the preflight predictions and demonstrated the value of active experiments that combine high-power radio waves with chemical releases. 30 refs., 14 figs., 1 tab.

  7. Non-Imaging, Focusing Heliostat

    Microsoft Academic Search

    Y. T. Chen; K. K. Chong; T. P. Bligh; L. C. Chen; Jasmy Yunus; K. S. Kannan; B. H. Lim; C. S. Lim; M. A. Alias; Noriah Bidin; Omar Aliman; Sahar Salehan; Shk. Abd. Rezan S. A. H; C. M. Tam; K. K. Tan

    2001-01-01

    A non-imaging focusing heliostat for effective use of thermal solar energy is proposed. The heliostat consists of a number of grouped slave mirrors, which are able to move according to a proposed formula to eliminate the first order aberration. The master mirror tracks the sun by a proposed rotation-elevation mode to project solar rays together with the rest of slave

  8. Staying in School. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1996

    1996-01-01

    This theme issue focuses on issues related to high Texas dropout rates among Hispanic and other minority group students and on dropout prevention strategies. "School Finance Inequities Mean Schools Are Not Ready To Teach" (Maria Robledo Montecel) deplores the recent Texas Supreme Court ruling that state educational funding is constitutional,…

  9. Student Focused Math Content Coaching

    NSDL National Science Digital Library

    David Foster

    This 8-page PDF details strategies used by math coaches in the Silicon Valley Mathematics Initiative where the focus is on students’ thinking and on their work products. This document includes various approaches that coaches may use with teachers to gain trust and important pre-observation and post observation questioning and reflection techniques.

  10. Video: Focusing a Compound Microscope

    NSDL National Science Digital Library

    This video from CUNY Kingsborough Community College describes how to focus a compound microscope. The brief clip, available for viewing on YouTube, would be most useful for students with a basic understanding of the parts of a compound microscope and how to use it. Running time for the video is 0:55.

  11. your position is our focus

    E-print Network

    Berns, Hans-Gerd

    !fundamentals! · u-blox!ANTARIS!GPS!technology! · System!design!and!layout!considerations! · Product!handling!and!production!testing! your position is our focus ANTARIS EvalKit GPS Evaluation Kit ANTARIS ® Positioning Engine ! ! ! The ANTARIS EvalKit is a ready-to-go starter kit that allows fast and easy evaluation of the ANTARIS GPS

  12. Focus Issue on Metamaterials INTRODUCTION

    E-print Network

    Shalaev, Vladimir M.

    Focus Issue on Metamaterials INTRODUCTION Within the past five years, metamaterials has become one of metamaterials, i.e., artificial materials with properties not available in nature, originated in the microwave and subwavelength imaging techniques. Metamateri- als are expected to open a new gateway to unprecedented

  13. Board Focus, 1997-1998.

    ERIC Educational Resources Information Center

    Giles, Ray, Ed.

    1998-01-01

    These four consecutive issues of the quarterly newsletter, "Board Focus," distributed by the Community College League of California, are dated spring, summer and fall 1997, and spring 1998. The spring 1997 issue discusses the "town vs. gown" conflict, which entails trustees balancing their obligations to operate the college on behalf of the…

  14. ERS Focus On: Educating Boys

    ERIC Educational Resources Information Center

    Clarke, Suzanne

    2007-01-01

    This issue of "Focus On" examines where boys are underachieving and some possible reasons for their under-achievement, including biological and environmental factors. It also offers strategies that teachers can employ in their classrooms in order to address the educational needs of boys. Books in Brief; Web Resources; and Related ERS Resources are…

  15. FOREWORD: Focus on Advanced Ceramics Focus on Advanced Ceramics

    NASA Astrophysics Data System (ADS)

    Ohashi, Naoki

    2011-06-01

    Much research has been devoted recently to developing technologies for renewable energy and improving the efficiency of the processes and devices used in industry and everyday life. Efficient solutions have been found using novel materials such as platinum and palladium-based catalysts for car exhaust systems, samarium-cobalt and neodymium-iron-boron permanent magnets for electrical motors, and so on. However, their realization has resulted in an increasing demand for rare elements and in their deficit, the development of new materials based on more abundant elements and new functionalities of traditional materials. Moreover, increasing environmental and health concerns demand substitution of toxic or hazardous substances with nature-friendly alternatives. In this context, this focus issue on advanced ceramics aims to review current trends in ceramics science and technology. It is related to the International Conference on Science and Technology of Advanced Ceramics (STAC) held annually to discuss the emerging issues in the field of ceramics. An important direction of ceramic science is the collaboration between experimental and theoretical sciences. Recent developments in density functional theory and computer technology have enabled the prediction of physical and chemical properties of ceramics, thereby assisting the design of new materials. Therefore, this focus issue includes articles devoted to theory and advanced characterization techniques. As mentioned above, the potential shortage of rare elements is becoming critical to the industry and has resulted in a Japanese government initiative called the 'Ubiquitous Element Strategy'. This focus issue also includes articles related to this strategy and to the associated topics of energy conversion, such as phosphors for high-efficiency lighting and photocatalysts for solar-energy harvesting. We hope that this focus issue will provide a timely overview of current trends and problems in ceramics science and technology and promote new research and development in this field.

  16. In vivo detection of ultrasonically induced cavitation by a fibre-optic technique.

    PubMed

    Huber, P; Debus, J; Peschke, P; Hahn, E W; Lorenz, W J

    1994-01-01

    The measurement of cavitation events in tissue in vivo would greatly assist us to better understand how pulsed high energy ultrasound (PHEUS) interacts with living tissues, especially with regard to cancer therapy. To accomplish this, we designed and built a fibre-optic hydrophone. The principle was to couple the light of a laser diode into a lightfibre and to register the ultrasound induced modification of the refractive index in tissue. In this manner, the cavitation event could be quantitatively investigated both in water and in vivo. The structure of the bubble dynamic is in reasonable agreement with theoretical predictions, and in vitro measurements. With the fibre-optic set-up, the pressure signal can also be detected. PHEUS was generated by an electromagnetic source adapted from a commercial lithotripter (Lithostar Siemens). As biological tissue we used the experimental R3327-AT1 Dunning prostate tumor growing subcutaneously in the thigh of male Copenhagen rats. The lifetime of the cavitation bubble in water increased with the energy level of the ultrasonic pulse from 250 microseconds at 13 kV capacitor voltage to 750 microseconds at 21 kV, while the lifetime inside the tumor tissue in vivo increased only from 100 microseconds at 13 kV to 220 microseconds at 21 kV capacitor voltage. PMID:7863570

  17. Graph-based anomaly detection

    Microsoft Academic Search

    Caleb C. Noble; Diane J. Cook

    2003-01-01

    Anomaly detection is an area that has received much attention in recent years. It has a wide variety of applications, including fraud detection and network intrusion detection. A good deal of research has been performed in this area, often using strings or attribute-value data as the medium from which anomalies are to be extracted. Little work, however, has focused on

  18. GRAVITATIONALLY FOCUSED DARK MATTER AROUND COMPACT STARS

    SciTech Connect

    Bromley, Benjamin C., E-mail: bromley@physics.utah.edu [Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Room 201, Salt Lake City, UT 84112 (United States)

    2011-12-01

    If dark matter self-annihilates then it may produce an observable signal when its density is high. The details depend on the intrinsic properties of dark matter and how it clusters in space. For example, the density profile of some dark matter candidates may rise steeply enough toward the Galactic Center that self-annihilation may produce detectable {gamma}-ray emission. Here, we discuss the possibility that an annihilation signal arises near a compact object (e.g., neutron star or black hole) even when the density of dark matter in the neighborhood of the object is uniform. Gravitational focusing produces a local enhancement of density with a profile that falls off approximately as the inverse square-root of distance from the compact star. While geometric dilution may overwhelm the annihilation signal from this local enhancement, magnetic fields tied to the compact object can increase the signal's contrast relative to the background.

  19. Focus Issue: Rendering Resistance Futile

    NSDL National Science Digital Library

    Elizabeth M. Adler (American Association for the Advancement of Science; Senior Editor of Science Signaling REV)

    2011-03-29

    In conjunction with the Science special issue on cancer (http://www.sciencemag.org/special/cancer2011/), this issue of Science Signaling focuses on mechanisms whereby cancer cells become resistant to antineoplastic therapy. This issue explores mechanisms whereby cancer cells can become resistant to classical chemotherapy drugs aimed at rapidly proliferating cells or to newer agents that depend on specific inhibition of oncogenic kinases or downstream components of aberrantly activated signaling pathways.

  20. Flow focusing with viscoelastic liquids

    NASA Astrophysics Data System (ADS)

    Derzsi, Ladislav; Kasprzyk, Marta; Plog, Jan Philip; Garstecki, Piotr

    2013-09-01

    We present an experimental comparative study of the effect of elasticity of the continuous liquid in generation of droplets in microfluidic flow focusing devices. For a wide range of values of dynamic viscosity of the Newtonian droplet phase we compare the dynamics of the formation of droplets in three different Newtonian and non-Newtonian, viscoelastic (Boger) fluid pairs of the same (and nearly constant) shear viscosities. In both Newtonian and viscoelastic systems we find similar regimes of operation of the system: (i) dripping without satellites, (ii) dripping with single satellites, (iii) formation of multiple satellites, and (iv) jetting. We find that the elasticity of the focusing liquid stabilizes the jets facilitating formation of smaller droplets, and leads to transitions between various regimes at lower ratios of flow and at lower values of the capillary numbers in comparison to the Newtonian focusing liquids. We also show that the polydispersity of Newtonian droplets produced in non-Newtonian continuous phases depend significantly on the viscosity of the droplet phase while this dependence is minor when the continuous liquid is Newtonian.

  1. Blue diode spectroscopy in a plasma focus device

    Microsoft Academic Search

    M. Mathuthu; T. G. Zengeni

    2004-01-01

    Summary form only given. The 405 nm blue diode has found many applications in medicine as a diagnostic tool for skin cancer. It has also been used to detect fluorescence from living plants, oils, paints etc. In this work, we report on the application of this laser as a diagnostic tool in a Plasma Focus Device (PFD). The PFD is

  2. Visual information foraging in a focus + context visualization

    Microsoft Academic Search

    Peter Pirolli; Stuart K. Card; Mija M. Van Der Wege

    2001-01-01

    Eye tracking studies of the Hyperbolic Tree browser [10] suggest that visual search in focus+context displays is highly affected by information scent (i.e., local cues, such as text summaries, used to assess and navigate toward distal information sources). When users detected a strong information scent, they were able to reach their goal faster with the Hyperbolic Tree browser than with

  3. Targeted therapy using nanotechnology: focus on cancer

    PubMed Central

    Sanna, Vanna; Pala, Nicolino; Sechi, Mario

    2014-01-01

    Recent advances in nanotechnology and biotechnology have contributed to the development of engineered nanoscale materials as innovative prototypes to be used for biomedical applications and optimized therapy. Due to their unique features, including a large surface area, structural properties, and a long circulation time in blood compared with small molecules, a plethora of nanomaterials has been developed, with the potential to revolutionize the diagnosis and treatment of several diseases, in particular by improving the sensitivity and recognition ability of imaging contrast agents and by selectively directing bioactive agents to biological targets. Focusing on cancer, promising nanoprototypes have been designed to overcome the lack of specificity of conventional chemotherapeutic agents, as well as for early detection of precancerous and malignant lesions. However, several obstacles, including difficulty in achieving the optimal combination of physicochemical parameters for tumor targeting, evading particle clearance mechanisms, and controlling drug release, prevent the translation of nanomedicines into therapy. In spite of this, recent efforts have been focused on developing functionalized nanoparticles for delivery of therapeutic agents to specific molecular targets overexpressed on different cancer cells. In particular, the combination of targeted and controlled-release polymer nanotechnologies has resulted in a new programmable nanotherapeutic formulation of docetaxel, namely BIND-014, which recently entered Phase II clinical testing for patients with solid tumors. BIND-014 has been developed to overcome the limitations facing delivery of nanoparticles to many neoplasms, and represents a validated example of targeted nanosystems with the optimal biophysicochemical properties needed for successful tumor eradication. PMID:24531078

  4. Multinode acoustic focusing for parallel flow cytometry

    PubMed Central

    Piyasena, Menake E.; Suthanthiraraj, Pearlson P. Austin; Applegate, Robert W.; Goumas, Andrew M.; Woods, Travis A.; López, Gabriel P.; Graves, Steven W.

    2012-01-01

    Flow cytometry can simultaneously measure and analyze multiple properties of single cells or particles with high sensitivity and precision. Yet, conventional flow cytometers have fundamental limitations with regards to analyzing particles larger than about 70 microns, analyzing at flow rates greater than a few hundred microliters per minute, and providing analysis rates greater than 50,000 per second. To overcome these limits, we have developed multi-node acoustic focusing flow cells that can position particles (as small as a red blood cell and as large as 107 microns in diameter) into as many as 37 parallel flow streams. We demonstrate the potential of such flow cells for the development of high throughput, parallel flow cytometers by precision focusing of flow cytometry alignment microspheres, red blood cells, and the analysis of CD4+ cellular immunophenotyping assay. This approach will have significant impact towards the creation of high throughput flow cytometers for rare cell detection applications (e.g. circulating tumor cells), applications requiring large particle analysis, and high volume flow cytometry. PMID:22239072

  5. Career Pathways: Focus on Biotechnology

    NSDL National Science Digital Library

    Career Pathways: Focus on Biotechnology is a students' guide to biotechnology careers in North Carolina. North Carolina has made biotechnology a central part of its economic development strategy and is home to over 350 bioscience companies who offer a wide variety of career opportunities. North Carolina has committed to programs at community colleges and universities that are industry-focused and provide hands-on training for an industry that places enormous value on the scientific and technical training of its employees. To support this industry, we want to assure that potential employees know about the opportunities available in biotechnology and the preparation required in high school and at the community college and university levels to make career choices in this field. Career pathways offer an approach to education that links what happens in the schools with opportunities in the real-world economy. At the high school level, career pathways group careers in related fields and indicate the courses students will need to succeed in any one of the careers. A career pathway is a course of study, focused on subjects related to a particular group of careers, which prepares students for their next steps in education. The North Carolina Department of Public Instruction has made a commitment to support the biotechnology industry. This guide defines the biotechnology industry by grouping related careers, describing the careers, and identifying courses students need in high school to choose careers in their area of interest. By linking education and the world of work, particularly the specific opportunities and workforce needs in biotechnology, schools can target instruction to fit students? needs, inspire students to build their own futures, and help create a workforce that meets the needs of the state economy.

  6. P-band focus problem

    NASA Astrophysics Data System (ADS)

    Mansfield, Arthur W.; Rais, Houra

    1997-06-01

    For the problem of finding downed aircraft in forested areas, the NASA Search and Rescue Project has developed a system based on using fully polarimetric L-Band and P-Band synthetic aperture radar (SAR). Because of the resolution of the sensor and the size of the target, single-look imagery must be used. The problem of focusing the SAR imagery is a difficult one, especially at P-Band. An approach has been implemented with considerable success, based on a variant of the phase gradient autofocus algorithm, which provides the higher-order-than- quadratic phase correction needed.

  7. Research Focus in Palliative Care

    PubMed Central

    Mohanti, Bidhu K

    2011-01-01

    This brief article on pre-conference CME topic ‘How to plan Research in Palliative Care’ is aimed to provide an overview of the background, concept, domains, present research activities and the future prospect for research opportunities. Advances in Palliative Care are made with a focus to address the quality of medical practice and ‘quality of death’, in those patients who have advanced stage diseases where cure may or may not be possible. The issues which can improve the palliative care delivery and the areas where evidence of practice is still weak can be identified by forming network and collaborative groups for the application of study and research methods in India. PMID:21811378

  8. Random Focusing of Tsunami Waves

    NASA Astrophysics Data System (ADS)

    Degueldre, Henri-Philippe; Metzger, Jakob J.; Fleischmann, Ragnar; Geisel, Theo

    2015-03-01

    When waves propagate through a weakly scattering, correlated random medium, the consecutive effects of small focusing events give rise to the phenomenon called branched flow, producing patterns of high intensity fluctuations. As tsunamis are deflected by underwater structures in the depth profile of the ocean floor, we investigate how it affects tsunami propagation and derive the typical length scale on which the highest waves are to be expected. We show that as a consequence of this effect the inaccuracies in the current knowledge of the ocean floor topography can prevent reliable tsunami forecasts on medium to large length scales.

  9. Focus Issue: Uncovering Immunological Secrets

    NSDL National Science Digital Library

    John F. Foley (American Association for the Advancement of Science; Associate Editors of Science's STKE REV)

    2007-08-07

    This Focus Issue of Science’s STKE complements a Special Issue of Science, which features a collection of Perspectives that describe obstacles to attaining a more complete understanding of the immune system. Taking stock of where the field now stands, the authors identify areas that warrant further investigation and speculate on the likely clinical benefits of achieving a deeper understanding of immune function. Articles in Science’s STKE highlight molecular challenges that immunologists have overcome, new questions that have arisen from their studies, and cutting-edge techniques that will enable immunologists to tackle these problems.

  10. Rotating apparatus for isoelectric focusing

    NASA Technical Reports Server (NTRS)

    Bier, Milan (Inventor)

    1986-01-01

    This disclosure is directed to an isoelectric focusing apparatus, wherein stabilization of the fluid containing the isolated proteins is achieved by carrying out the separation in a rotating cylinder with the separation cavity of the cylinder being segmented by means of filter elements. The filter elements are constituted of a material offering some degree of resistance to fluid convection, but allowing relatively free and unhindered passage of current and transport of proteins. The combined effect of segmentation and rotation has been found to be superior to either segmentation or rotation alone in maintaining the stability of the migrated fractions.

  11. EDITORIAL: Focus on Cloud Physics FOCUS ON CLOUD PHYSICS

    NASA Astrophysics Data System (ADS)

    Falkovich, Gregory; Malinowski, Szymon P.

    2008-07-01

    Cloud physics has for a long time been an important segment of atmospheric science. It is common knowledge that clouds are crucial for our understanding of weather and climate. Clouds are also interesting by themselves (not to mention that they are beautiful). Complexity is hidden behind the common picture of these beautiful and interesting objects. The typical school textbook definition that a cloud is 'a set of droplets or particles suspended in the atmosphere' is not adequate. Clouds are complicated phenomena in which dynamics, turbulence, microphysics, thermodynamics and radiative transfer interact on a wide range of scales, from sub-micron to kilometres. Some of these interactions are subtle and others are more straightforward. Large and small-scale motions lead to activation of cloud condensation nuclei, condensational growth and collisions; small changes in composition and concentration of atmospheric aerosol lead to significant differences in radiative properties of the clouds and influence rainfall formation. It is justified to look at a cloud as a composite, nonlinear system which involves many interactions and feedback. This system is actively linked into a web of atmospheric, oceanic and even cosmic interactions. Due to the complexity of the cloud system, present-day descriptions of clouds suffer from simplifications, inadequate parameterizations, and omissions. Sometimes the most fundamental physics hidden behind these simplifications and parameterizations is not known, and a wide scope of view can sometimes prevent a 'microscopic', deep insight into the detail. Only the expertise offered by scientists focused on particular elementary processes involved in this complicated pattern of interactions allows us to shape elements of the puzzle from which a general picture of clouds can be created. To be useful, every element of the puzzle must be shaped precisely. This often creates problems in communication between the sciences responsible for shaping elements of the puzzle, and those which combine them. Scales, assumptions and the conditions used in order to describe a particular single process of interest must be consistent with the conditions in clouds. The papers in this focus issue of New Journal of Physics collectively demonstrate (i) the variation in scientific approaches towards investigating cloud processes, (ii) the various stages of shaping elements of the puzzle, and (iii) some attempts to put the pieces together. These papers present just a small subset of loosely arranged elements in an initial stage of puzzle creation. Addressed by this issue is one of the important problems in our understanding of cloud processes—the interaction between cloud particles and turbulence. There is currently a gap between the cloud physics community and scientists working in wind tunnels, on turbulence theory and particle interactions. This collection is intended to narrow this gap by bringing together work by theoreticians, modelers, laboratory experimentalists and those who measure and observe actual processes in clouds. It forms a collage of contributions showing various approaches to cloud processes including: • theoretical works with possible applications to clouds (Bistagnino and Boffetta, Gustavsson et al), • an attempt to construct a phenomenological description of clouds and rain (Lovejoy and Schertzer), • simplified models designed to parameterize turbulence micro- and macro-effects (Celani et al, Derevyanko et al), • focused theoretical research aimed at particular cloud processes (Ayala et al, parts I and II, Wang et al), • laboratory and modeling studies of complex cloud processes (Malinowski et al). This collage is far from being complete but, hopefully, should give the reader a representative impression of the current state of knowledge in the field. We hope it will be useful to all scientists whose work is inspired by cloud processes. Focus on Cloud Physics Contents The development of ice in a cumulus cloud over southwest England Yahui Huang, Alan M Blyth, Philip R A Brown, Tom W Choularton,

  12. Future focus for professional development.

    PubMed

    Roberts, Nicole K; Coplit, Lisa D

    2013-01-01

    Professional development has evolved from individually focused sabbaticals and professional leaves to institutionally focused programs with an interest in developing faculty members' ability to teach in various environments as well as to succeed in the many endeavors they undertake. We address various issues related to professional development in the medical school arena. Professional development in medical school takes place in a context where faculty are stretched to engage in research and service not only for their own sake but also to financially support their institutions. This obligates professional developers to acknowledge and address the environments in which teaching faculty work, and to use approaches to professional development that honor the time and efforts of teaching faculty. These approaches may be brief interventions that make use of principles of education, and may include online offerings. Professional development will be most effective when professional developers acknowledge that most faculty members aspire to excellence in teaching, but they do so in an environment that pushes them to address competing concerns. Offering professional development opportunities that fit within the workplace environment, take little time, and build upon faculty's existing knowledge will assist in enhancing faculty success. PMID:24246108

  13. Plutonium focus area. Technology summary

    SciTech Connect

    NONE

    1997-09-01

    The Assistant Secretary for the Office of Environmental Management (EM) at the U.S. Department of Energy (DOE) chartered the Plutonium Focus Area (PFA) in October 1995. The PFA {open_quotes}...provides for peer and technical reviews of research and development in plutonium stabilization activities...{close_quotes} In addition, the PFA identifies and develops relevant research and technology. The purpose of this document is to focus attention on the requirements used to develop research and technology for stabilization, storage, and preparation for disposition of nuclear materials. The PFA Technology Summary presents the approach the PFA uses to identify, recommend, and review research. It lists research requirements, research being conducted, and gaps where research is needed. It also summarizes research performed by the PFA in the traditional research summary format. This document encourages researchers and commercial enterprises to do business with PFA by submitting research proposals or {open_quotes}white papers.{close_quotes} In addition, it suggests ways to increase the likelihood that PFA will recommend proposed research to the Nuclear Materials Stabilization Task Group (NMSTG) of DOE.

  14. Focus on the Rashba effect

    NASA Astrophysics Data System (ADS)

    Bihlmayer, G.; Rader, O.; Winkler, R.

    2015-05-01

    The Rashba effect, discovered in 1959, continues to supply fertile ground for fundamental research and applications. It provided the basis for the proposal of the spin transistor by Datta and Das in 1990, which has largely inspired the broad and dynamic field of spintronics. More recent developments include new materials for the Rashba effect such as metal surfaces, interfaces and bulk materials. It has also given rise to new phenomena such as spin currents and the spin Hall effect, including its quantized version, which has led to the very active field of topological insulators. The Rashba effect plays a crucial role in yet more exotic fields of physics such as the search for Majorana fermions at semiconductor-superconductor interfaces and the interaction of ultracold atomic Bose and Fermi gases. Advances in our understanding of Rashba-type spin-orbit couplings, both qualitatively and quantitatively, can be obtained in many different ways. This focus issue brings together the wide range of research activities on Rashba physics to further promote the development of our physical pictures and concepts in this field. The present Editorial gives a brief account on the history of the Rashba effect including material that was previously not easily accessible before summarizing the key results of the present focus issue as a guidance to the reader.

  15. Antipodal focusing of seismic waves observed with the USArray

    PubMed Central

    Retailleau, L.; Shapiro, N. M.; Guilbert, J.; Campillo, M.; Roux, P.

    2014-01-01

    We present an analysis of the Mw = 5.3 earthquake that occurred in the Southeast Indian Ridge on 2010 February 11 using USArray data. The epicentre of this event is antipodal to the USArray, providing us with an opportunity to observe in details the antipodal focusing of seismic waves in space and time. We compare the observed signals with synthetic seismograms computed for a spherically symmetric earth model (PREM). A beamforming analysis is performed over the different seismic phases detected at antipodal distances. Direct spatial snapshots of the signals and the beamforming results show that the focusing is well predicted for the first P-wave phases such as PKP or PP. However, converted phases (SKSP, PPS) show a deviation of the energy focusing to the south, likely caused by the Earth's heterogeneity. Focusing of multiple S-wave phases strongly deteriorates and is barely observable.

  16. Antipodal focusing of seismic waves observed with the USArray

    NASA Astrophysics Data System (ADS)

    Retailleau, L.; Shapiro, N. M.; Guilbert, J.; Campillo, M.; Roux, P.

    2014-11-01

    We present an analysis of the Mw = 5.3 earthquake that occurred in the Southeast Indian Ridge on 2010 February 11 using USArray data. The epicentre of this event is antipodal to the USArray, providing us with an opportunity to observe in details the antipodal focusing of seismic waves in space and time. We compare the observed signals with synthetic seismograms computed for a spherically symmetric earth model (PREM). A beamforming analysis is performed over the different seismic phases detected at antipodal distances. Direct spatial snapshots of the signals and the beamforming results show that the focusing is well predicted for the first P-wave phases such as PKP or PP. However, converted phases (SKSP, PPS) show a deviation of the energy focusing to the south, likely caused by the Earth's heterogeneity. Focusing of multiple S-wave phases strongly deteriorates and is barely observable.

  17. Ballistic Focusing of Polyenergetic Protons Driven by Petawatt Laser Pulses

    NASA Astrophysics Data System (ADS)

    Kar, S.; Markey, K.; Borghesi, M.; Carroll, D. C.; McKenna, P.; Neely, D.; Quinn, M. N.; Zepf, M.

    2011-06-01

    By using a thick (250?m) target with 350?m radius of curvature, the intense proton beam driven by a petawatt laser is focused at a distance of ˜1mm from the target for all detectable energies up to ˜25MeV. The thickness of the foil facilitates beam focusing as it suppresses the dynamic evolution of the beam divergence caused by peaked electron flux distribution at the target rear side. In addition, reduction in inherent beam divergence due to the target thickness relaxes the curvature requirement for short-range focusing. Energy resolved mapping of the proton beam trajectories from mesh radiographs infers the focusing and the data agree with a simple geometrical modeling based on ballistic beam propagation.

  18. Focused ultrasound treatment of abscesses induced by methicillin resistant Staphylococcus aureus: Feasibility study in a mouse model

    SciTech Connect

    Rieck, Birgit [Thunder Bay Regional Research Institute, Thunder Bay, Ontario P7B6V4 (Canada)] [Thunder Bay Regional Research Institute, Thunder Bay, Ontario P7B6V4 (Canada); Bates, David; Pichardo, Samuel, E-mail: spichard@lakeheadu.ca, E-mail: lcuriel@lakeheadu.ca; Curiel, Laura, E-mail: spichard@lakeheadu.ca, E-mail: lcuriel@lakeheadu.ca [Thunder Bay Regional Research Institute, Thunder Bay, Ontario P7B6V4, Canada and Lakehead University, Thunder Bay, Ontario P7B6V4 (Canada)] [Thunder Bay Regional Research Institute, Thunder Bay, Ontario P7B6V4, Canada and Lakehead University, Thunder Bay, Ontario P7B6V4 (Canada); Zhang, Kunyan [Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta T2N 1N4 (Canada)] [Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Escott, Nicholas [Department of Pathology, Thunder Bay Regional Health Sciences Centre, Thunder Bay, Ontario P7B 6V4 (Canada)] [Department of Pathology, Thunder Bay Regional Health Sciences Centre, Thunder Bay, Ontario P7B 6V4 (Canada); Mougenot, Charles [Philips Healthcare, Ontario L6C 2S3 (Canada)] [Philips Healthcare, Ontario L6C 2S3 (Canada)

    2014-06-15

    Purpose: To study the therapeutic effect of focused ultrasound on abscesses induced by methicillin-resistantStaphylococcus aureus (MRSA). MRSA is a major nosocomial pathogen where immunocompromised patients are prone to develop infections that are less and less responsive to regular treatments. Because of its capability to induce a rise of temperature at a very precise location, the use of focused ultrasound represents a considerable opportunity for therapy of localized MRSA-related infections. Methods: 50?l of MRSA strain USA400 bacteria suspension at a concentration of 1.32 ± 0.5 × 10{sup 5} colony forming units (cfu)/?l was injected subcutaneously in the left flank of BALB/c mice. An abscess of 6 ± 2 mm in diameter formed after 48 h. A transducer operating at 3 MHz with a focal length of 50 mm and diameter of 32 mm was used to treat the abscess. The focal point was positioned 2 mm under the skin at the abscess center. Forty-eight hours after injection four ultrasound exposures of 9 s each were applied to each abscess under magnetic resonance imaging guidance. Each exposure was followed by a 1 min pause. These parameters were based on preliminary experiments to ensure repetitive accurate heating of the abscess. Real-time estimation of change of temperature was done using water-proton resonance frequency and a communication toolbox (matMRI) developed inhouse. Three experimental groups of animals each were tested: control, moderate temperature (MT), and high temperature (HT). MT and HT groups reached, respectively, 52.3 ± 5.1 and 63.8 ± 7.5?°C at the end of exposure. Effectiveness of the treatment was assessed by evaluating the bacteria amount of the treated abscess 1 and 4 days after treatment. Myeloperoxidase (MPO) assay evaluating the neutrophil amount was performed to assess the local neutrophil recruitment and the white blood cell count was used to evaluate the systemic inflammatory response after focused ultrasound treatment. Results: Macroscopic evaluation of treated abscess indicated a diminution of external size of abscess 1 day after treatment. Treatment did not cause open wounds. The median (lower to upper quartile) bacterial count 1 day after treatment was 6.18 × 10{sup 3} (0.76 × 10{sup 3}–11.18 × 10{sup 3}), 2.86 × 10{sup 3} (1.22 × 10{sup 3}–7.07 × 10{sup 3}), and 3.52 × 10{sup 3} (1.18 × 10{sup 3}–6.72 × 10{sup 3}) cfu/100 ?l for control, MT and HT groups, respectively; for the 4-day end point, the count was 1.37 × 10{sup 3} (0.67 × 10{sup 3}–2.89 × 10{sup 3}), 1.35 × 10{sup 3} (0.09 × 10{sup 3}–2.96 × 10{sup 3}), and 0.07 × 10{sup 3} (0.03 × 10{sup 3}–0.36 × 10{sup 3}) cfu/100 ?l for control, MT and HT, showing a significant reduction (p = 0.002) on the bacterial load four days after focused ultrasound treatment when treating at high temperature (HT). The MPO amount remained unchanged between groups and days, indicating no change on local neutrophil recruitment in the abscess caused by the treatment. The white blood cell count remained unchanged between groups and days indicating that no systemic inflammatory response was caused by the treatment. Conclusions: Focused ultrasound induces a therapeutic effect in abscesses induced by MRSA. This effect is observed as a reduction of the number bacteria without significantly altering the amount of MPO at the site of a MRSA-induced abscess. These initial results suggest that focused ultrasound is a viable option for the treatment of localized MRSA-related infections.

  19. Signal focusing through active transport

    E-print Network

    Aljaz Godec; Ralf Metzler

    2015-01-13

    In biological cells and novel diagnostic devices biochemical receptors need to be sensitive to extremely small concentration changes of signaling molecules. The accuracy of such molecular signaling is ultimately limited by the counting noise imposed by the thermal diffusion of molecules. Many macromolecules and organelles transiently bind to molecular motors and are then actively transported. We here show that a random albeit directed delivery of signaling molecules to within a typical diffusion distance to the receptor reduces the correlation time of the counting noise, effecting an improved sensing precision. The conditions for this active focusing are indeed compatible with observations in living cells. Our results are relevant for a better understanding of molecular cellular signaling and the design of novel diagnostic devices.

  20. Signal focusing through active transport

    E-print Network

    Godec, Aljaz

    2015-01-01

    In biological cells and novel diagnostic devices biochemical receptors need to be sensitive to extremely small concentration changes of signaling molecules. The accuracy of such molecular signaling is ultimately limited by the counting noise imposed by the thermal diffusion of molecules. Many macromolecules and organelles transiently bind to molecular motors and are then actively transported. We here show that a random albeit directed delivery of signaling molecules to within a typical diffusion distance to the receptor reduces the correlation time of the counting noise, effecting an improved sensing precision. The conditions for this active focusing are indeed compatible with observations in living cells. Our results are relevant for a better understanding of molecular cellular signaling and the design of novel diagnostic devices.

  1. Non-focusing active warhead

    DOEpatents

    Hornig, Howard C. (Castro Valley, CA)

    1998-01-01

    A non-nuclear, non-focusing, active warhead that comprises a high explosive charge contained within a casing of reactive metal. When the high explosive is detonated, the reactive metal is dispersed and reacts with the air, which significantly increases the explosive yield of the warhead. The active warhead produces therefore much higher blast effects with significantly reduced weight compared to conventional munitions. The warhead is highly effective against such targets as aircraft which typically have thin fuselages, for example. The explosiveness of this warhead can be enhanced further by elevating the temperature and therefore the reactivity of the reactive metal before or during the explosion. New methods of enhancing the reactivity of the metal are also taught.

  2. ESPERE Project: Focus on Agronomy

    NASA Astrophysics Data System (ADS)

    de La Osa, J.; Iglesias, A.

    2003-04-01

    ESPERE (Environmental Science Published for Everybody Round the Earth) aims to bring the current scientific knowledge of the climate system and its impacts to schools. The Spanish partner (IAMZ) is responsible for: (1) delivering peer-reviewed, reliable information on the impacts, vulnerability and adaptation of agriculture to climate; (2) promoting the interactive cooperation among scientists and non-scientists in the Spanish Educational System; and (3) working in the Spanish language; and (4) revising the content of the other focus areas for their adequacy in the education system of Spain. The presentation will discuss the approach taken in each of the four actions of IAMZ based on past experience and results, present the progress on cooperation with a Pilot School District, and provide the documents produced in Spanish as initial stages of capacity building and outreach.

  3. Rotating Apparatus for Isoelectric Focusing

    NASA Technical Reports Server (NTRS)

    Bier, M.

    1986-01-01

    Remixing of separated fractions prevented. Improved isoelectric focusing apparatus helps to prevent electro-osmosis and convection, both of which cause remixing of separated fractions. Fractionating column segmented and rotated about horizontal axis: Only combined effects of both features fully effective in making good separations. Improved apparatus slowly rotated continuously or rocked (at rotational amplitude of at least 180 degrees) about its horizontal axis so average gravitational vector experienced by fluid is zero and convection is therefore suppressed. Electro-osmosis suppressed and convection further suppressed by separating column into disklike compartments along its length with filters. Experiments have shown dimensions of apparatus not critical. Typical compartment and column volumes are 2 and 40 ml, respectively. Rotation speeds lie between 3 and 30 rpm.

  4. EDITORIAL: Focus on Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    2003-09-01

    The study of carbon nanotubes, since their discovery by Iijima in 1991, has become a full research field with significant contributions from all areas of research in solid-state and molecular physics and also from chemistry. This Focus Issue in New Journal of Physics reflects this active research, and presents articles detailing significant advances in the production of carbon nanotubes, the study of their mechanical and vibrational properties, electronic properties and optical transitions, and electrical and transport properties. Fundamental research, both theoretical and experimental, represents part of this progress. The potential applications of nanotubes will rely on the progress made in understanding their fundamental physics and chemistry, as presented here. We believe this Focus Issue will be an excellent guide for both beginners and experts in the research field of carbon nanotubes. It has been a great pleasure to edit the many excellent contributions from Europe, Japan, and the US, as well from a number of other countries, and to witness the remarkable effort put into the manuscripts by the contributors. We thank all the authors and referees involved in the process. In particular, we would like to express our gratitude to Alexander Bradshaw, who invited us put together this Focus Issue, and to Tim Smith and the New Journal of Physics staff for their extremely efficient handling of the manuscripts. Focus on Carbon Nanotubes Contents <;A article="1367-2630/5/1/117">Transport theory of carbon nanotube Y junctions R Egger, B Trauzettel, S Chen and F Siano The tubular conical helix of graphitic boron nitride F F Xu, Y Bando and D Golberg Formation pathways for single-wall carbon nanotube multiterminal junctions Inna Ponomareva, Leonid A Chernozatonskii, Antonis N Andriotis and Madhu Menon Synthesis and manipulation of carbon nanotubes J W Seo, E Couteau, P Umek, K Hernadi, P Marcoux, B Lukic, Cs Mikó, M Milas, R Gaál and L Forró Transitional behaviour in the transformation from active end planes to stable loops caused by annealing M Endo, B J Lee, Y A Kim, Y J Kim, H Muramatsu, T Yanagisawa, T Hayashi, M Terrones and M S Dresselhaus Energetics and electronic structure of C70-peapods and one-dimensional chains of C70 Susumu Okada, Minoru Otani and Atsushi Oshiyama Theoretical characterization of several models of nanoporous carbon F Valencia, A H Romero, E Hernández, M Terrones and H Terrones First-principles molecular dynamics study of the stretching frequencies of hydrogen molecules in carbon nanotubes Gabriel Canto, Pablo Ordejón, Cheng Hansong, Alan C Cooper and Guido P Pez The geometry and the radial breathing mode of carbon nanotubes: beyond the ideal behaviour Jeno Kürti, Viktor Zólyomi, Miklos Kertesz and Sun Guangyu Curved nanostructured materials Humberto Terrones and Mauricio Terrones A one-dimensional Ising model for C70 molecular ordering in C70-peapods Yutaka Maniwa, Hiromichi Kataura, Kazuyuki Matsuda and Yutaka Okabe Nanoengineering of carbon nanotubes for nanotools Yoshikazu Nakayama and Seiji Akita Narrow diameter double-wall carbon nanotubes: synthesis, electron microscopy and inelastic light scattering R R Bacsa, E Flahaut, Ch Laurent, A Peigney, S Aloni, P Puech and W S Bacsa Sensitivity of sin

  5. Dark focus measured in Navy jet tactical fighter pilots.

    PubMed

    Temme, L A; Ricks, E; Morris, A

    1988-02-01

    Visual accommodation was measured with the laser-Badal optometer in 98 U.S. Navy fighter pilots who were in a dark environment without visual stimuli. The average dark focus of the pilots was 0.25 diopters of myopia; 40% were either emmetropic or hyperopic in the dark. Only 4% had as much dark myopia as 50% of a sample of 220 college students. Although the jet fighter pilots, as a population, differed from college students in terms of dark focus, it remains to be determined whether the remarkable dark focus of the pilots was a function of training or selection. The dark focus measurements of the pilots were compared to their mean night carrier landing scores and their mean target detection slant range scores--the distance at which an adversary aircraft is first sighted during an air combat maneuver training engagement. Neither the night carrier landing scores nor the target detection slant range scores correlated significantly with dark focus measurements. PMID:3345175

  6. The Unfocused Focus Group: Benefit or Bane?

    ERIC Educational Resources Information Center

    Franz, Nancy K.

    2011-01-01

    Facilitating successful focus groups requires both science and art. One element that can fully challenge focus group facilitators includes how to handle the unfocused focus group. This article describes "unfocus" and the benefits and disadvantages of unfocus in focus groups. Lessons learned from and approaches taken on this journey are shared to…

  7. EDITORIAL: Focus on Attosecond Physics

    NASA Astrophysics Data System (ADS)

    Bandrauk, André D.; Krausz, Ferenc; Starace, Anthony F.

    2008-02-01

    Investigations of light matter interactions and motion in the microcosm have entered a new temporal regime, the regime of attosecond physics. It is a main 'spin-off' of strong field (i.e., intense laser) physics, in which nonperturbative effects are fundamental. Attosecond pulses open up new avenues for time-domain studies of multi-electron dynamics in atoms, molecules, plasmas, and solids on their natural, quantum mechanical time scale and at dimensions shorter than molecular and even atomic scales. These capabilities promise a revolution in our microscopic knowledge and understanding of matter. The recent development of intense, phase-stabilized femtosecond (10-15 s) lasers has allowed unparalleled temporal control of electrons from ionizing atoms, permitting for the first time the generation and measurement of isolated light pulses as well as trains of pulses on the attosecond (1 as = 10-18 s) time scale, the natural time scale of the electron itself (e.g., the orbital period of an electron in the ground state of the H atom is 152 as). This development is facilitating (and even catalyzing) a new class of ultrashort time domain studies in photobiology, photochemistry, and photophysics. These new coherent, sub-fs pulses carried at frequencies in the extreme ultraviolet and soft-x-ray spectral regions, along with their intense, synchronized near-infrared driver waveforms and novel metrology based on sub-fs control of electron light interactions, are spawning the new science of attosecond physics, whose aims are to monitor, to visualize, and, ultimately, to control electrons on their own time and spatial scales, i.e., the attosecond time scale and the sub-nanometre (Ångstrom) spatial scale typical of atoms and molecules. Additional goals for experiment are to advance the enabling technologies for producing attosecond pulses at higher intensities and shorter durations. According to theoretical predictions, novel methods for intense attosecond pulse generation may in future involve using overdense plasmas. Electronic processes on sub-atomic spatio-temporal scales are the basis of chemical physics, atomic, molecular, and optical physics, materials science, and even some life science processes. Research in these areas using the new attosecond tools will advance together with the ability to control electrons themselves. Indeed, we expect that developments will advance in a way that is similar to advances that have occurred on the femtosecond time scale, in which much previous experimental and theoretical work on the interaction of coherent light sources has led to the development of means for 'coherent control' of nuclear motion in molecules. This focus issue of New Journal of Physics is centered on experimental and theoretical advances in the development of new methodologies and tools for electron control on the attosecond time scale. Topics such as the efficient generation of harmonics; the generation of attosecond pulses, including those having only a few cycles and those produced from overdense plasmas; the description of various nonlinear, nonperturbative laser matter interactions, including many-electron effects and few-cycle pulse effects; the analysis of ultrashort propagation effects in atomic and molecular media; and the development of inversion methods for electron tomography, as well as many other topics, are addressed in the current focus issue dedicated to the new field of 'Attosecond Physics'. Focus on Attosecond Physics Contents Observing the attosecond dynamics of nuclear wavepackets in molecules by using high harmonic generation in mixed gases Tsuneto Kanai, Eiji J Takahashi, Yasuo Nabekawa and Katsumi Midorikawa Core-polarization effects in molecular high harmonic generation G Jordan and A Scrinzi Interferometric autocorrelation of an attosecond pulse train calculated using feasible formulae Y Nabekawa and K Midorikawa Attosecond pulse generation from aligned molecules—dynamics and propagation in H2+ E Lorin, S Chelkowski and A D Bandrauk Broadband generation in a Raman crystal driven by a pair of time-de

  8. The MINDS - Minnesota Intrusion Detection System

    Microsoft Academic Search

    Levent Ert; Eric Eilertson; Pang-Ning Tan; Vipin Kumar; Jaideep Srivastava

    This paper introduces the Minnesota Intrusion Detection System (MINDS), which uses a suite of data mining techniques to automatically detect attacks against computer net- works and systems. While the long-term objective of MINDS is to address all aspects of intrusion detection, in this paper we focus on two specic contributions. First, we show how the behavior-based anomaly detection approach of

  9. Mood as a determinant of attentional focus

    Microsoft Academic Search

    Constantine Sedikides

    1992-01-01

    Three experiments examined the effects of mood on self-focused versus external-focused attention. The results demonstrated that sad mood (compared to neutral and happy mood) tends to induce self-focused attention, whereas happy mood (compared to sad mood) tends to elicit external-focused attention. The effects of mood on attention were independent of the self-focusing nature of the mood-inducing event. A model is

  10. Findings: LANL outsourcing focus groups

    SciTech Connect

    Jannotta, M.J.; McCabe, V.B.

    1996-12-31

    In March 1996, a series of 24 3-hour dialog focus groups were held with randomly selected Laboratory employees and contractors to gain their perceptions regarding potentials and problems for privatization and consolidation. A secondary goal was to educate and inform the workforce about potentials and issues in privatization and consolidation. Two hundred and thirty-six participants engaged in a learning session and structured input exercises resulting in 2,768 usable comments. Comments were categorized using standard qualitative methods; resulting categories included positive and negative comments on four models (consolidation, spin offs, outsourcing, and corporate partnering) and implications for the workforce, the Laboratory, and the local economy. Categories were in the areas of increasing/decreasing jobs, expertise, opportunity/salary/benefits, quality/efficiency, and effect on the local area and economy. An additional concern was losing Laboratory culture and history. Data were gathered and categorized on employee opinion regarding elements of successful transition to the four models, and issues emerged in the areas of terms and conditions of employment; communication; involvement; sound business planning; ethics and fairness; community infrastructure. From the aggregated opinion of the participants, it is recommended that decision-makers: Plan using sound business principles and continually communicate plans to the workforce; Respect workforce investments in the Laboratory; Tell the workforce exactly what is going on at all times; Understand that economic growth in Northern New Mexico is not universally viewed as positive; and Establish dialog with stakeholders on growth issues.

  11. Prime Focus Spectrograph - Subaru's future -

    E-print Network

    Sugai, Hajime; Takato, Naruhisa; Tamura, Naoyuki; Shimono, Atsushi; Ohyama, Youichi; Ueda, Akitoshi; Ling, Hung-Hsu; de Arruda, Marcio Vital; Barkhouser, Robert H; Bennett, Charles L; Bickerton, Steve; Braun, David F; Bruno, Robin J; Carr, Michael A; Oliveira, João Batista de Carvalho; Chang, Yin-Chang; Chen, Hsin-Yo; Dekany, Richard G; Dominici, Tania Pereira; Ellis, Richard S; Fisher, Charles D; Gunn, James E; Heckman, Timothy M; Ho, Paul T P; Hu, Yen-Shan; Jaquet, Marc; Karr, Jennifer; Kimura, Masahiko; Fèvre, Olivier Le; Mignant, David Le; Loomis, Craig; Lupton, Robert H; Madec, Fabrice; Marrara, Lucas Souza; Martin, Laurent; Murayama, Hitoshi; de Oliveira, Antonio Cesar; de Oliveira, Claudia Mendes; de Oliveira, Ligia Souza; Orndorff, Joe D; Vilaça, Rodrigo de Paiva; Macanhan, Vanessa Bawden de Paula; Prieto, Eric; Santos, Jesulino Bispo dos; Seiffert, Michael D; Smee, Stephen A; Smith, Roger M; Sodré, Laerte; Spergel, David N; Surace, Christian; Vives, Sebastien; Wang, Shiang-Yu; Yan, Chi-Hung

    2012-01-01

    The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project has been endorsed by Japanese community as one of the main future instruments of the Subaru 8.2-meter telescope at Mauna Kea, Hawaii. This optical/near-infrared multi-fiber spectrograph targets cosmology with galaxy surveys, Galactic archaeology, and studies of galaxy/AGN evolution. Taking advantage of Subaru's wide field of view, which is further extended with the recently completed Wide Field Corrector, PFS will enable us to carry out multi-fiber spectroscopy of 2400 targets within 1.3 degree diameter. A microlens is attached at each fiber entrance for F-ratio transformation into a larger one so that difficulties of spectrograph design are eased. Fibers are accurately placed onto target positions by positioners, each of which consists of two stages of piezo-electric rotary motors, through iterations by using back-illuminated fiber position measurements with a wide-field metrology camera. Fibers then carry l...

  12. Focused electron beam induced deposition: A perspective

    PubMed Central

    Porrati, Fabrizio; Schwalb, Christian; Winhold, Marcel; Sachser, Roland; Dukic, Maja; Adams, Jonathan; Fantner, Georg

    2012-01-01

    Summary Background: Focused electron beam induced deposition (FEBID) is a direct-writing technique with nanometer resolution, which has received strongly increasing attention within the last decade. In FEBID a precursor previously adsorbed on a substrate surface is dissociated in the focus of an electron beam. After 20 years of continuous development FEBID has reached a stage at which this technique is now particularly attractive for several areas in both, basic and applied research. The present topical review addresses selected examples that highlight this development in the areas of charge-transport regimes in nanogranular metals close to an insulator-to-metal transition, the use of these materials for strain- and magnetic-field sensing, and the prospect of extending FEBID to multicomponent systems, such as binary alloys and intermetallic compounds with cooperative ground states. Results: After a brief introduction to the technique, recent work concerning FEBID of Pt–Si alloys and (hard-magnetic) Co–Pt intermetallic compounds on the nanometer scale is reviewed. The growth process in the presence of two precursors, whose flux is independently controlled, is analyzed within a continuum model of FEBID that employs rate equations. Predictions are made for the tunability of the composition of the Co–Pt system by simply changing the dwell time of the electron beam during the writing process. The charge-transport regimes of nanogranular metals are reviewed next with a focus on recent theoretical advancements in the field. As a case study the transport properties of Pt–C nanogranular FEBID structures are discussed. It is shown that by means of a post-growth electron-irradiation treatment the electronic intergrain-coupling strength can be continuously tuned over a wide range. This provides unique access to the transport properties of this material close to the insulator-to-metal transition. In the last part of the review, recent developments in mechanical strain-sensing and the detection of small, inhomogeneous magnetic fields by employing nanogranular FEBID structures are highlighted. Conclusion: FEBID has now reached a state of maturity that allows a shift of the focus towards the development of new application fields, be it in basic research or applied. This is shown for selected examples in the present review. At the same time, when seen from a broader perspective, FEBID still has to live up to the original idea of providing a tool for electron-controlled chemistry on the nanometer scale. This has to be understood in the sense that, by providing a suitable environment during the FEBID process, the outcome of the electron-induced reactions can be steered in a controlled way towards yielding the desired composition of the products. The development of a FEBID-specialized surface chemistry is mostly still in its infancy. Next to application development, it is this aspect that will likely be a guiding light for the future development of the field of focused electron beam induced deposition. PMID:23019557

  13. [Treatment of refractory glaucoma with high density focused ultrasonics].

    PubMed

    Valtot, F; Kopel, J; Petit, E; Moulin, F; Haut, J

    1995-01-01

    The efficacy of therapeutic ultrasound was retrospectively assessed in 456 patients who presented with uncontrolled glaucoma refractory to maximal medical therapy and filtration surgery from April 1987 to January 1992. Treatment was performed under local anaesthesia in ambulatory outpatients. Therapeutic ultrasound induced local destruction of the ciliary epithelium and a thickening of the sclera. A 47% decrease in intraocular pressure (IOP) was obtained from the mean preoperative (33.8 mmHg) and the mean postoperative (18.2 mm Hg) values. After a 33-month mean follow-up, 65% of treated eyes had an IOP less than or egal to 20 mmHg. Therapeutic ultrasound was effective in most of the glaucomas, especially in open angle, closed angle, aphakic, pseudophakic and post-silicone oil glaucoma. The main complications were immediate ocular hypertension and corneoscleral alterations. Phtysis bulbi occurred in 5.7% of the eyes. The therapeutic interest of ultrasound were compared with those of the other cyclodestruction techniques. PMID:7738293

  14. Molecular collisions coming into focus.

    PubMed

    Onvlee, Jolijn; Vogels, Sjoerd N; von Zastrow, Alexander; Parker, David H; van de Meerakker, Sebastiaan Y T

    2014-08-14

    The Stark deceleration method exploits the concepts of charged particle accelerator physics to produce beams of neutral polar molecules with an almost perfect quantum state purity, a tunable velocity and a narrow velocity distribution. These monochromatic molecular beams offer interesting perspectives for precise studies of molecular scattering processes, in particular when used in conjunction with state-of-the-art laser-based detection techniques such as velocity map imaging. Here, we describe crossed beam scattering experiments in which the Stark deceleration method is combined with the velocity map imaging technique. The narrow velocity spread of Stark-decelerated molecular beams results in scattering images with unprecedented velocity and angular resolution. We demonstrate this by resolving quantum diffraction oscillations in state-to-state inelastic differential scattering cross sections for collisions between NO radicals and rare gas atoms. We describe the future prospects of this "best-of-two-worlds" combination, ranging from scattering studies at low collision energies to bimolecular scattering using two decelerators, and discuss the challenges that lie ahead to achieve these goals. PMID:24967721

  15. Focusing on Cause or Cure?

    PubMed Central

    Milner, Lauren C.; Cho, Mildred K.

    2013-01-01

    Background Biomedical research is influenced by many factors, including the involvement of stakeholder groups invested in research outcomes. Stakeholder involvement in research efforts raise questions of justice as their specific interests and motivations play a role in directing research resources that ultimately produce knowledge shaping how different conditions (and affected individuals) are understood and treated by society. This issue is highly relevant to child psychiatry research where diagnostic criteria and treatment strategies are often controversial. Biological similarities and stakeholder differences between attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) provide an opportunity to explore this issue by comparing research foci and stakeholder involvement in these conditions. Methods A subset of ADHD and ASD research articles published between 1970-2010 were randomly selected from the PubMed database and coded for research focus, funding source(s), and author-reported conflicts of interest (COIs). Chi-square analyses were performed to identify differences between and within ADHD and ASD research across time. Results The proportion of ADHD research dedicated to basic, description, and treatment research was roughly similar and remained stable over time, while ASD research showed a significant increase in basic research over the past decade. Government was the primary research funder for both conditions, but for-profit funders were a notable presence in ADHD research, while joint-funding efforts between non-profit and government funders were a notable presence in ASD research. Lastly, COIs were noted more frequently in ADHD than in ASD research. Conclusions Our study shows significant differences in research foci and funding sources between the conditions, and identifies the specific involvement of for-profit and non-profit groups in ADHD and ASD, respectively. Our findings highlight the relationship between stakeholders outside the research community and research trajectories and suggest that examinations of these relationships must be included in broader considerations of biomedical research ethics. PMID:24729931

  16. Prime focus spectrograph: Subaru's future

    NASA Astrophysics Data System (ADS)

    Sugai, Hajime; Karoji, Hiroshi; Takato, Naruhisa; Tamura, Naoyuki; Shimono, Atsushi; Ohyama, Youichi; Ueda, Akitoshi; Ling, Hung-Hsu; Vital de Arruda, Marcio; Barkhouser, Robert H.; Bennett, Charles L.; Bickerton, Steve; Braun, David F.; Bruno, Robin J.; Carr, Michael A.; Batista de Carvalho Oliveira, João.; Chang, Yin-Chang; Chen, Hsin-Yo; Dekany, Richard G.; Pereira Dominici, Tania; Ellis, Richard S.; Fisher, Charles D.; Gunn, James E.; Heckman, Timothy; Ho, Paul T. P.; Hu, Yen-Shan; Jaquet, Marc; Karr, Jennifer; Kimura, Masahiko; Le Fèvre, Olivier C.; Le Mignant, David; Loomis, Craig; Lupton, Robert H.; Madec, Fabrice; Marrara, Lucas; Martin, Laurent; Murayama, Hitoshi; Cesar de Oliveira, Antonio; Mendes de Oliveira, Claudia; Souza de Oliveira, Ligia; Orndorff, Joseph D.; de Paiva Vilaça, Rodrigo M. P.; Macanhan, Vanessa B. d. P.; Prieto, Eric; Bispo dos Santos, Jesulino; Seiffert, Michael; Smee, Stephen A.; Smith, Roger M.; Sodré, Laerte; Spergel, David N.; Surace, Christian; Vives, Sebastien; Wang, Shiang-Yu; Yan, Chi-Hung

    2012-09-01

    The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project has been endorsed by Japanese community as one of the main future instruments of the Subaru 8.2-meter telescope at Mauna Kea, Hawaii. This optical/near-infrared multi-fiber spectrograph targets cosmology with galaxy surveys, Galactic archaeology, and studies of galaxy/AGN evolution. Taking advantage of Subaru's wide field of view, which is further extended with the recently completed Wide Field Corrector, PFS will enable us to carry out multi-fiber spectroscopy of 2400 targets within 1.3 degree diameter. A microlens is attached at each fiber entrance for F-ratio transformation into a larger one so that difficulties of spectrograph design are eased. Fibers are accurately placed onto target positions by positioners, each of which consists of two stages of piezo-electric rotary motors, through iterations by using back-illuminated fiber position measurements with a widefield metrology camera. Fibers then carry light to a set of four identical fast-Schmidt spectrographs with three color arms each: the wavelength ranges from 0.38 ?m to 1.3 ?m will be simultaneously observed with an average resolving power of 3000. Before and during the era of extremely large telescopes, PFS will provide the unique capability of obtaining spectra of 2400 cosmological/astrophysical targets simultaneously with an 8-10 meter class telescope. The PFS collaboration, led by IPMU, consists of USP/LNA in Brazil, Caltech/JPL, Princeton, and JHU in USA, LAM in France, ASIAA in Taiwan, and NAOJ/Subaru.

  17. AXAF VETA-I mirror ring focus measurements

    NASA Technical Reports Server (NTRS)

    Tananbaum, H. D.; Zhao, P.

    1994-01-01

    The AXAF VETA-I mirror ring focus measurements were made with an HRI (microchannel plate) X-ray detector. The ring focus is a sharply focused ring formed by X-rays before they reach the VEAT-I focal plane. It is caused by spherical aberrations due to the finite source distance and the despace in the VETA-I test. The ring focus test reveals some aspects fo the test system distortions and the mirror surface figure which are difficult or impossible to detect at the focal plane. The test results show periodic modulations of the ring radius and width which could be caused by gravity, thermal, and/or epoxy shrinkage distortions. The strongest component of the modulation had a 12-fold symmetry, because these distortions were exerted on the mirror through 12 flexures of the VETA-I mount. Ring focus models were developed to simulate the ring image. The models were compared with the data to understand the test system distortions and the mirror glass imperfection. Further studies will be done to complete this work. The ring focus measurement is a very powerful test. We expect that a similar test for the finally assembled mirror of AXAD-I will be highly valuable.

  18. AUTOMATIC SECTION THICKNESS DETERMINATION USING AN ABSOLUTE GRADIENT FOCUS FUNCTION

    PubMed Central

    Elozory, Daniel T.; Kramer, Kurt A.; Chaudhuri, Baishali; Bonam, Om P.; Goldgof, Dmitry B.; Hall, Lawrence O.; Mouton, Peter R.

    2015-01-01

    Quantitative analysis of microstructures using computerized stereology systems is an essential tool in many disciplines of bioscience research. Section thickness determination in current non-automated approaches requires manual location of upper and lower surfaces of tissue sections. In contrast to conventional autofocus functions that locate the optimally focused optical plane using the global maximum on a focus curve, the present study identified by two sharp “knees” on the focus curve as the transition from unfocused to focused optical planes. Analysis of fourteen gray-scale focus functions showed, the thresholded absolute gradient function, was best for finding detectable bends that closely correspond to the bounding optical planes at the upper and lower tissue surfaces. Modifications to this function generated four novel functions that outperformed the original. The “modified absolute gradient count” function outperformed all others with an average error of 0.56 ?m on a test set of images similar to the training set; and, an average error of 0.39 ?m on a test set comprised of images captured from a different case, i.e., different staining methods on a different brain region from a different subject rat. We describe a novel algorithm that allows for automatic section thickness determination based on just out-of-focus planes, a prerequisite for fully automatic computerized stereology. PMID:23078150

  19. Trapping cavitation bubbles with a self-focused laser beam

    Microsoft Academic Search

    Jing Yong Ye; Guoqing Chang; Theodore B. Norris; Christine Tse; Marwa J. Zohdy; Kyle W. Hollman; Matthew O'Donnell; James R. Baker Jr.

    2004-01-01

    We observed that laser-induced cavitation bubbles in water can be trapped in a self-focused laser beam. Both optical imaging and acoustic detection have been utilized to confirm bubble trapping. Transverse and longitudinal trapping forces were measured to be as large as 87 and 11 pN, respectively. This result is contrary to conventional wisdom, since the mechanism of trapping in conventional

  20. Detection of a Novel Mechanism of Acousto-Optic Modulation of Incoherent Light

    PubMed Central

    Jarrett, Christopher W.; Caskey, Charles F.; Gore, John C.

    2014-01-01

    A novel form of acoustic modulation of light from an incoherent source has been detected in water as well as in turbid media. We demonstrate that patterns of modulated light intensity appear to propagate as the optical shadow of the density variations caused by ultrasound within an illuminated ultrasonic focal zone. This pattern differs from previous reports of acousto-optical interactions that produce diffraction effects that rely on phase shifts and changes in light directions caused by the acoustic modulation. Moreover, previous studies of acousto-optic interactions have mainly reported the effects of sound on coherent light sources via photon tagging, and/or the production of diffraction phenomena from phase effects that give rise to discrete sidebands. We aimed to assess whether the effects of ultrasound modulation of the intensity of light from an incoherent light source could be detected directly, and how the acoustically modulated (AOM) light signal depended on experimental parameters. Our observations suggest that ultrasound at moderate intensities can induce sufficiently large density variations within a uniform medium to cause measurable modulation of the intensity of an incoherent light source by absorption. Light passing through a region of high intensity ultrasound then produces a pattern that is the projection of the density variations within the region of their interaction. The patterns exhibit distinct maxima and minima that are observed at locations much different from those predicted by Raman-Nath, Bragg, or other diffraction theory. The observed patterns scaled appropriately with the geometrical magnification and sound wavelength. We conclude that these observed patterns are simple projections of the ultrasound induced density changes which cause spatial and temporal variations of the optical absorption within the illuminated sound field. These effects potentially provide a novel method for visualizing sound fields and may assist the interpretation of other hybrid imaging methods. PMID:25105880

  1. Techniques For Focusing In Zone Electrophoresis

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Twitty, Garland E.; Sammons, David W.

    1994-01-01

    In two techniques for focusing in zone electrophoresis, force of applied electrical field in each charged particle balanced by restoring force of electro-osmosis. Two techniques: velocity-gradient focusing (VGF), suitable for rectangular electrophoresis chambers; and field-gradient focusing (FGF), suitable for step-shaped electrophoresis chambers.

  2. Electrostatic focusing of unlabelled DNA into nanoscale pores using a salt gradient

    E-print Network

    Electrostatic focusing of unlabelled DNA into nanoscale pores using a salt gradient Meni Wanunu1 of a 20-fold salt gradient allows the detection of picomolar DNA concentrations at high throughput. The salt gradients enhance the electric field, focusing more molecules into the pore, thereby advancing

  3. Focused echocardiographic evaluation in life support and peri-resuscitation of emergency patients: A prospective trial

    Microsoft Academic Search

    Raoul Breitkreutz; Susanna Price; Holger V. Steiger; Florian H. Seeger; Hendrik Ilper; Hanns Ackermann; Marcus Rudolph; Shahana Uddin; Markus A. Weigand; Edgar Müller; Felix Walcher

    2010-01-01

    Purpose of the studyFocused ultrasound is increasingly used in the emergency setting, with an ALS-compliant focused echocardiography algorithm proposed as an adjunct in peri-resuscitation care (FEEL). The purpose of this study was to evaluate the feasibility of FEEL in pre-hospital resuscitation, the incidence of potentially treatable conditions detected, and the influence on patient management.

  4. Performance Improvement of Algorithms Based on the Synthetic Aperture Focusing Technique

    NASA Astrophysics Data System (ADS)

    Acevedo, P.; Sotomayor, A.; Moreno, E.

    An analysis to improve the performance of the ultrasonic synthetic aperture focusing technique (SAFT) on a PC platform is presented in this paper. Some useful processing techniques like apodization, dynamic focusing, envelope detection and image composition are used to improve the quality of the image. Finally, results of the algorithm implemented using MATLAB and C/C++ and the respective images are presented

  5. Analysis of flexural mode focusing by a semianalytical finite element method

    Microsoft Academic Search

    Zongqi Sun; Joseph L. Roseb; Joseph L. Rose

    2003-01-01

    Focusing is one of the most promising techniques for the detection of small defects in pipe works, in which guided waves including longitudinal and flexural modes are tuned so that ultrasonic energy can be focused at a target point in a pipe, and analysis of reflected waves gives information on defects such as location and size. In this paper, the

  6. Quantitative results from the focusing schlieren technique

    NASA Technical Reports Server (NTRS)

    Cook, S. P.; Chokani, Ndaona

    1993-01-01

    An iterative theoretical approach to obtain quantitative density data from the focusing schlieren technique is proposed. The approach is based on an approximate modeling of the focusing action in a focusing schlieren system, and an estimation of an appropriate focal plane thickness. The theoretical approach is incorporated in a computer program, and results obtained from a supersonic wind tunnel experiment evaluated by comparison with CFD data. The density distributions compared favorably with CFD predictions. However, improvements to the system are required in order to reduce noise in the data, to improve specifications of a depth of focus, and to refine the modeling of the focusing action.

  7. Focused Ultrasound and Microbubbles for Enhanced Extravasation

    PubMed Central

    Böhmer, M. R.; Chlon, C. H. T.; Raju, B. I.; Chin, C. T.; Shevchenko, T.; Klibanov, A. L.

    2010-01-01

    The permeability of blood vessels for albumin can be altered by using ultrasound and polymer or lipid-shelled microbubbles. The region in which the microbubbles were destroyed with focused ultrasound was quantified in gel phantoms as a function of pressure, number of cycles and type of microbubble. At 2 MPa the destruction took place in a fairly wide area for a lipid-shelled agent, while for polymer-shelled agents at this setting, distinct destruction spots with a radius of only 1 mm were obtained. When microbubbles with a thicker shell were used, the pressure above which the bubbles were destroyed shifts to higher values. In vivo both lipid and polymer microbubbles increased the extravasation of the albumin binding dye Evans Blue, especially in muscle leading to about 6–8% of the injected dose to extravasate per gram muscle tissue 30 minutes after start of the treatment, while no Evans Blue could be detected in muscle in the absence of microbubbles. Variation in the time between ultrasound treatment and Evans Blue injection, demonstrated that the time window for promoting extravasation is at least an hour at the settings used. In MC38 tumors, extravasation already occurred without ultrasound and only a trend towards enhancement with about a factor 2 could be established with a maximum percentage injected dose per gram of 3%. Ultrasound mediated microbubble destruction especially enhances the extravasation in the highly vascularized outer part of the MC38 tumor and adjacent muscle and would, therefore, be most useful for release of, for instance, anti-angiogenic drugs. PMID:20600402

  8. Persistent High Self-Focus After Failure and Low Self-Focus After Success: The Depressive Self-Focusing Style

    Microsoft Academic Search

    Jeff Greenberg; Tom Pyszczynski

    1986-01-01

    Two studies were conducted to assess the spontaneous self-focusing tendencies of depressed and nondepressed individuals after success and failure. Based on a self-regulatory perseveration theory of depression, it was expected that depressed individuals would be especially high in self-focus after failure and low in self-focus after success. The results of Experiment 1 suggested that immediately after an outcome, both depressed

  9. Real-time new event detection for video streams

    Microsoft Academic Search

    Gang Luo; Rong Yan; Philip S. Yu

    2008-01-01

    Online detection of video clips that present previously unseen events in a video stream is still an open challenge to date. For this online new event detection (ONED) task, existing studies mainly focus on optimizing the detection accuracy instead of the detection efficiency. As a result, it is difficult for existing systems to detect new events in real time, especially

  10. Needs of Non Energy-Focused Contractors

    SciTech Connect

    Liaukus, C.

    2012-12-01

    To better understand the informational needs of non energy-focused contractors, including what information they need to motivate them to become energy-focused, the BARA team studied the type of information provided by the national programs, trade associations, and manufacturers that were researched for the related technical report: Effective Communication of Energy Efficiency. While that report focused on the delivery method, format, and strategy of the information, this study examines the content being put forward.

  11. A Probabilistic Framework for Aircraft Conflict Detection

    Microsoft Academic Search

    Maria Prandini; John Lygeros; Arnab Nilim; Shankar Sastry

    1999-01-01

    In this paper we describe a general conflict detection\\/resolution scheme for a pair of aircraftflying at the same altitude, focusing on the conflict detection component. The proposed approachis formulated in a probabilistic framework, thus allowing uncertainty in the aircraft positions tobe explicitly taken into account when detecting a potential conflict. The computational issuesinvolved in the application of the proposed conflict

  12. EXPLOSIVES DETECTION: A Challenge for Physical Chemistry

    Microsoft Academic Search

    Jeffrey I. Steinfeld; Jody Wormhoudt

    1998-01-01

    The detection of explosives, energetic materials, and their associated compounds for security screening, demining, detection of unexploded ordnance, and pollution monitoring is an active area of research. A wide variety of detection methods and an even wider range of physical chemistry issues are involved in this very challenging area. This review focuses on techniques such as optical and mass spectrometry

  13. Focus-of-attention for human activity recognition from UAVs

    NASA Astrophysics Data System (ADS)

    Burghouts, G. J.; van Eekeren, A. W. M.; Dijk, J.

    2014-10-01

    This paper presents a system to extract metadata about human activities from full-motion video recorded from a UAV. The pipeline consists of these components: tracking, motion features, representation of the tracks in terms of their motion features, and classification of each track as one of the human activities of interest. We consider these activities: walk, run, throw, dig, wave. Our contribution is that we show how a robust system can be constructed for human activity recognition from UAVs, and that focus-of-attention is needed. We find that tracking and human detection are essential for robust human activity recognition from UAVs. Without tracking, the human activity recognition deteriorates. The combination of tracking and human detection is needed to focus the attention on the relevant tracks. The best performing system includes tracking, human detection and a per-track analysis of the five human activities. This system achieves an average accuracy of 93%. A graphical user interface is proposed to aid the operator or analyst during the task of retrieving the relevant parts of video that contain particular human activities. Our demo is available on YouTube.

  14. Best focus shift mechanism for thick masks

    NASA Astrophysics Data System (ADS)

    Burkhardt, Martin; Raghunathan, Ananthan

    2015-03-01

    The best focus shift due to thick mask effects is well known, both in ArF, and more importantly in EUV, where the shorter wavelength is small compared to both mask openings and absorber height. While the effect is stronger in opaque features in clear field masks, the best focus shift is visible in dark field masks as well, and it becomes even more pronounced when scattering bars are added to non-dense features. This pattern dependent focus variation can be predicted in both exact EMF simulations and fast image calculations that are used for optical proximity correction (OPC). Even though this focus shift can be predicted and patterns can be corrected in OPC, we would like to understand the mechanism that causes this focus shift. This can help us understand if, in addition to best focus shift, the image quality is further deteriorated due to the thick mask effects. The best focus shift is found to be an interplay of the complex diffraction coefficient due to thick mask effects and the direction of the light that is incident on the mask, or coherence value ?. A change in focus adds a phase term to each of the complex diffraction coefficients, causing their rotation in a phasor diagram. Best focus is found when the phasors have an angle of 0 or 180 degrees to each other and depending on which diffracted orders are caught in the pupil and contribute to imaging. We investigate the effect of partial coherence, mask thickness, and assist feature placement on best focus shift. We observe a waveguide effect in the absorber gaps because of the reduced real index of refraction in the absorber layer, making vacuum the optically dense medium. We suggest ways to lessen the best focus shifts through assist feature placement or the use of alternative absorbers that are closer matched to the dielectric index of vacuum.

  15. Viscoelastic effects on electrokinetic particle focusing in a constricted microchannel.

    PubMed

    Lu, Xinyu; DuBose, John; Joo, Sang Woo; Qian, Shizhi; Xuan, Xiangchun

    2015-01-01

    Focusing suspended particles in a fluid into a single file is often necessary prior to continuous-flow detection, analysis, and separation. Electrokinetic particle focusing has been demonstrated in constricted microchannels by the use of the constriction-induced dielectrophoresis. However, previous studies on this subject have been limited to Newtonian fluids only. We report in this paper an experimental investigation of the viscoelastic effects on electrokinetic particle focusing in non-Newtonian polyethylene oxide solutions through a constricted microchannel. The width of the focused particle stream is found NOT to decrease with the increase in DC electric field, which is different from that in Newtonian fluids. Moreover, particle aggregations are observed at relatively high electric fields to first form inside the constriction. They can then either move forward and exit the constriction in an explosive mode or roll back to the constriction entrance for further accumulations. These unexpected phenomena are distinct from the findings in our earlier paper [Lu et al., Biomicrofluidics 8, 021802 (2014)], where particles are observed to oscillate inside the constriction and not to pass through until a chain of sufficient length is formed. They are speculated to be a consequence of the fluid viscoelasticity effects. PMID:25713690

  16. Improved 3D cellular imaging by multispectral focus assessment

    NASA Astrophysics Data System (ADS)

    Zhao, Tong; Xiong, Yizhi; Chung, Alice P.; Wachman, Elliot S.; Farkas, Daniel L.

    2005-03-01

    Biological specimens are three-dimensional structures. However, when capturing their images through a microscope, there is only one plane in the field of view that is in focus, and out-of-focus portions of the specimen affect image quality in the in-focus plane. It is well-established that the microscope"s point spread function (PSF) can be used for blur quantitation, for the restoration of real images. However, this is an ill-posed problem, with no unique solution and with high computational complexity. In this work, instead of estimating and using the PSF, we studied focus quantitation in multi-spectral image sets. A gradient map we designed was used to evaluate the sharpness degree of each pixel, in order to identify blurred areas not to be considered. Experiments with realistic multi-spectral Pap smear images showed that measurement of their sharp gradients can provide depth information roughly comparable to human perception (through a microscope), while avoiding PSF estimation. Spectrum and morphometrics-based statistical analysis for abnormal cell detection can then be implemented in an image database where the axial structure has been refined.

  17. Design of micromachined self-focusing piezoelectric composite ultrasound transducer.

    PubMed

    Xiaohua Jian; Yongjia Xiang; Zhile Han; Zhangjian Li; Yaoyao Cui

    2014-08-01

    Based on the Fresnel half-wave band interference, a micromachined self-focusing piezoelectric composite ultrasound transducer was proposed in this paper. The theoretical analysis was deduced based on the concept of constructive interference of acoustic waves and electromechanical response of piezoelectric composites. The calculated and simulation results showed that it combined the advantages of composite transducer and plate self-focusing transducer, and can achieve high electromechanical coupling coefficient, low acoustic impedance, high intensity, short focal length and micro size. Because it was based on the micro-electromechanical systems, the fabrication process was accurate and controllable, which made it have good potential for interventional ultrasound imaging, cellular microstructure imaging, skin cancer detection and industrial nondestructive testing applications. PMID:25570018

  18. Perspectives on Focus Group Participation and Remuneration

    Microsoft Academic Search

    Maghboeba Mosavel; Catherine Oakar

    2009-01-01

    Recruiting participants from underserved and marginalized communities for behavioral research is an essential yet challenging task. We examined participants' motivation to participate in a focus group about health communication and their beliefs about appropriate remuneration for participation. Twelve focus groups were conducted with low-income African American and Latina adolescent girls and African American women. We utilized a grounded theory approach

  19. Workforce Competencies: Focus on Urban Public Libraries

    Microsoft Academic Search

    Maria E. Gonzalez

    2010-01-01

    :Urban library leaders convened in 2008 to explore gaps between essential organizational competencies and the individual competencies of professionals entering the field. The 2008 Urban Libraries Summit aimed to focus collective wisdom in shaping suitable curricula for the education and training of future library professionals. This article examines the results of focus groups undertaken at that time, which identified current

  20. Out of Focus: Children's Conceptions of AIDS.

    ERIC Educational Resources Information Center

    Brown, Larry K.; And Others

    1994-01-01

    Reports a study that used focus group discussions to evaluate fifth graders' understanding of human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome before receiving HIV education. Results indicated students' conceptions about HIV were more naive than expected. The focus groups were effective in evaluating students' process of…

  1. Optimizing ultrasound focus distributions for hyperthermia

    Microsoft Academic Search

    Ronald J. Lalonde; John W. Hunt

    1995-01-01

    A method is described for generating ultrasound focus patterns for ultrasound hyperthermia treatment planning for steady state and transient hyperthermia. The solution for placement and intensity of ultrasound focus points is based on two types of temperature constraints: 1) equality constraints on the tumor boundary (temperature is held at maximum safe level), and 2) inequality constraints in the tumor interior

  2. Solution-Focused Therapy in Prison

    Microsoft Academic Search

    Lotta Lindforss; Dan Magnusson

    1997-01-01

    This is a report on a combined therapy and research project conducted with a seriously criminal population in Swedish prisons and using a Solution-Focused Brief Therapy approach with a focus on networks. Recidivism was significantly lower and less serious among experimental group participants. A case study is included.

  3. Using Focus Group Research in Public Relations.

    ERIC Educational Resources Information Center

    Grunig, Larissa A.

    1990-01-01

    Analyzes a recent instance of focus group research applied to a public relations case (rather than a marketing case). Reviews the advantages and disadvantages of this qualitative method, and describes the case of a county department of mental health relying on focus group research to help plan a program aimed at reducing the stigma of mental…

  4. Focused tsunami waves BY M. V. BERRY

    E-print Network

    Berry, Michael Victor

    Focused tsunami waves BY M. V. BERRY H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UK Shallower regions in the oceans can act as lenses, focusing the energy of tsunamis, typically of a tsunami wave propagating through a cusp. The wave elevation depends on position, time and two main

  5. Focused Monitoring. Alliance Action Information Sheets

    ERIC Educational Resources Information Center

    Technical Assistance ALLIANCE for Parent Centers, 2005

    2005-01-01

    During this era of increased accountability and enhanced educational expectations for infants, toddlers and students with disabilities, the U.S. Department of Education, Office of Special Education Programs (OSEP) is using a new compliance and technical assistance model- focused monitoring. Focused monitoring is part of the Continuous Improvement…

  6. Teaching Focus Group Interviewing: Benefits and Challenges

    ERIC Educational Resources Information Center

    George, Molly

    2013-01-01

    Focus group interviewing is widely used by academic and applied researchers. Given the popularity and strengths of this method, it is surprising how rarely focus group interviewing is taught in the undergraduate classroom and how few resources exist to support instructors who wish to train students to use this technique. This article fills the gap…

  7. Focusing One's Microscope By Daniel Pauly

    E-print Network

    Pauly, Daniel

    The Lead Focusing One's Microscope By Daniel Pauly Sea Around Us Project, Fisheries Centre discoveries are often a matter of focusing one's microscope -- actual or virtual -- and so rules have emerged's Microscope. The Science Chronicles (The Nature Conservancy), January 2011: 4-7. #12;! Establishing

  8. Accuracy of Information Processing under Focused Attention.

    ERIC Educational Resources Information Center

    Bastick, Tony

    This paper reports the results of an experiment on the accuracy of information processing during attention focused arousal under two conditions: single estimation and double estimation. The attention of 187 college students was focused by a task requiring high level competition for a monetary prize ($10) under severely limited time conditions. The…

  9. Identifying Information Focuses in Listening Comprehension

    ERIC Educational Resources Information Center

    Zhang, Hong-yan

    2011-01-01

    The study explains the process of learners' listening comprehension within Halliday's information theory in functional grammar, including the skills of identifying focuses while listening in college English teaching. Identifying information focuses in listening is proved to improve the students' communicative listening ability by the means of a…

  10. Seismic Migration For Sar Focusing: Interferometrical Applications

    Microsoft Academic Search

    Claudio Prati; FABIO ROCCA; A. M. Guarnieri; Elvio Damonti

    1990-01-01

    Conventional techniques for Synthetic Aperture Radar (SAR) image focusing use the matched filter concept and convolve the data with a reference phase signal which changes with range. The re- sulting algorithm is space-variant and its frequency-domain implemen- tation is cumbersome. SAR data, however, can be focused using mi- gration techniques identical to those used in seismic qignal processing for oil

  11. Inclusive Focus Particles in English and Korean

    ERIC Educational Resources Information Center

    Kang, Sang-gu

    2011-01-01

    When discussing focus particles, it has been common practice to rely on the dichotomy of inclusive vs. exclusive particles, "a la" Konig (1991). Inclusive focus particles are often further divided into scalar particles, such as "also", "too", and "either", and non-scalar particles, such as "even". In this thesis, I advance a comparative analysis…

  12. On FOCUS: Photographs and Writings by Students.

    ERIC Educational Resources Information Center

    Strohmeyer, Beatriz; McGrail, Loren

    Project FOCUS is aimed at enhancing literacy education for non-native speakers of English through the use of photography. It was offered as an elective course within a family literacy program for Hispanic adults. This collection of writings and photographs originated in the program. The collection begins with an overview of Project FOCUS, personal…

  13. Optimum annular focusing by a phase plate

    E-print Network

    Arrizón, Victor; Aguirre-Olivas, Dilia; Mellado-Villaseñor, Gabriel

    2015-01-01

    Conventional light focusing, i. e. concentration of an extended optical field within a small area around a point, is a frequently used process in Optics. An important extension to conventional focusing is the generation of the annular focal field of an optical beam. We discuss a simple optical setup that achieves this kind of focusing employing a phase plate as unique optical component. We first establish the class of beams that being transmitted through the phase plate can be focused into an annular field with topological charge of arbitrary integer order q. Then, for each beam in this class we determine the plate transmittance that generates the focal field with the maximum possible peak intensity. In particular, we discuss and implement experimentally the optimum annular focusing of a Gaussian beam. The attributes of optimum annular focal fields, namely the high peak intensity, intensity gradient and narrow annular section, are advantageous for different applications of such structured fields.

  14. Detection and handling of occlusion in an object detection system

    NASA Astrophysics Data System (ADS)

    Op het Veld, R. M. G.; Wijnhoven, R. G. J.; Bondarev, Y.; de With, Peter H. N.

    2015-03-01

    Object detection is an important technique for video surveillance applications. Although different detection algorithms were proposed, they all have problems in detecting occluded objects. In this paper, we propose a novel system for occlusion handling and integrate this in a sliding-window detection framework using HOG features and linear classification. The occlusion handling is obtained by applying multiple classifiers, each covering a different level of occlusion and focusing on the non-occluded object parts. Experiments show that our approach based on 17 classifiers, obtains an increase of 8% in detection performance. To limit computational complexity, we propose a cascaded implementation that only increases the computational cost by 3.4%. Although the paper presents results for pedestrian detection, our approach is not limited to this object class. Finally, our system does not need an additional dataset for training, covering all possible types of occlusions.

  15. Focusing on moving targets through scattering samples

    PubMed Central

    Zhou, Edward Haojiang; Ruan, Haowen; Yang, Changhuei; Judkewitz, Benjamin

    2014-01-01

    Focusing light through scattering media has been a longstanding goal of biomedical optics. While wavefront shaping and optical time-reversal techniques can in principle be used to focus light across scattering media, achieving this within a scattering medium with a noninvasive and efficient reference beacon, or guide star, remains an important challenge. Here, we show optical time-reversal focusing using a new technique termed Time Reversal by Analysis of Changing wavefronts from Kinetic targets (TRACK). By taking the difference between time-varying scattering fields caused by a moving object and applying optical time reversal, light can be focused back to the location previously occupied by the object. We demonstrate this approach with discretely moved objects as well as with particles in an aqueous flow, and obtain a focal peak-to-background strength of 204 in our demonstration experiments. We further demonstrate that the generated focus can be used to noninvasively count particles in a flow-cytometry configuration—even when the particles are hidden behind a strong diffuser. By achieving optical time reversal and focusing noninvasively without any external guide stars, using just the intrinsic characteristics of the sample, this work paves the way to a range of scattering media imaging applications, including underwater and atmospheric focusing as well as noninvasive in vivo flow cytometry. PMID:25621302

  16. Particle focusing mechanisms in curving confined flows.

    PubMed

    Gossett, Daniel R; Di Carlo, Dino

    2009-10-15

    Particles in finite-inertia confined channel flows are known to segregate and focus to equilibrium positions whose number corresponds with the fold of symmetry of the channel's cross section. The addition of curvature into channels presumably modifies these equilibrium inertial focusing positions, because of the secondary flow induced in curved channels. Here, we identify the critical interaction of the secondary flow field with inertial lift forces to create complex sets of particle focusing positions that vary with the channel Reynolds number (Re(C)) and the inertial force ratio, which is a new dimensionless parameter that is based on the ratio of inertial lift to drag forces from the secondary flow. We use these results to identify microfluidic channel geometries to focus particles at rates an order of magnitude higher than previously shown (channel Reynolds number, Re(C) = 270) and develop design criteria for the focusing of potentially arbitrary-sized particles. In addition, our results indicate that channel curvature can lead to microfluidic designs with reduced fluidic resistance, useful for lower power inertial focusing or separation. These results will enable design of practical particle/cell separation, filtration, and focusing systems for critical applications in biomedicine and environmental cleanup. PMID:19761190

  17. EDITORIAL: Focus on Micro- and Nanofluidics FOCUS ON MICRO- AND NANOFLUIDICS

    NASA Astrophysics Data System (ADS)

    Ajdari, Armand; Stone, Howard A.

    2009-07-01

    This focus issue of New Journal of Physics concentrates on recent developments in microfluidics, and related small-scale flow themes. This subject touches on many areas with the common element that they are engaged with understanding, measuring or manipulating flows at the scale of a few hundred microns or smaller. Microfluidics is of interest to many scientists and engineers from many disciplines because it is a toolbox from which they can investigate basic questions in their respective fields. In particular, the field has led to new studies of small-scale fluid flows, especially those dominated by surface effects, which is crucial for understanding electrokinetics, chemical reactions and phase changes, and multiphase systems, including those involving dispersed liquid and gas phases, suspended particles, cells, vesicles, capsules, etc. The lower length scale of these kinds of flows concerns nanoscale manipulation of objects such as DNA or nanoparticles, nanofabrication of surfaces, studies of the flow within nanometers of substrates, etc. Microfluidics has also given rise to technologies because it enables design and implementation of new devices for sensing, detection, measurement, materials characterization, combinatorial discovery, cellular-scale manipulation, miniaturization of reactors, etc. The fact that these systems are small, cheap, physically flexible, portable, multifunctional, and, when they are working, produce measurements quickly, offers many new avenues for innovation. In this issue we highlight contributions from around the world that explore research directions inspired by the manifold possibilities of microfluidics. In particular, the papers include reports of single-phase flows that are driven by electrical fields, so-called electrokinetics. Although the field has its origins in the 19th century, if not even earlier, new theoretical ideas are required to understand dynamics close to charged surfaces, and new applications of the basic ideas are being introduced for driving flows and manipulating suspended particles (e.g. DNA). In addition, the subject of mixing and the study of transport processes coupling diffusion and convection is a necessary component of many studies aimed at lab-on-a-chip environments. At the other extreme from mixing there is interest in the precise placement of particles in microfluidic flows. Although the majority of microfluidic studies focus on the consequences of low Reynolds number motions, the flows can frequently have large enough particle-scale Reynolds numbers that inertial effects can appear. Also, chemical gradients, via osmotic effects, can be significant, and, where surface effects are significant, particle deposition can occur. Multiphase flows constitute another major area of microfluidic research. For example, there has been great interest in using drops as individual containers since both the chemical composition inside and outside the drop can be controlled. Also, the interface between the two phases provides both a natural chemical barrier (surfactants are generally added to reduce the probability of coalescence between drops) as well as potentially being the site for reactions or localized organization of particles suspended in solution. Thus, there is interest in both the controlled breakup of liquid threads, the dynamics of such a thread, which can fold or buckle, and application of these processes to fabricating new materials. Not surprisingly the themes mentioned in this short summary are just a small window into the myriad of ideas being investigated in the research world of small-scale flows that is the playground of micro- and nanofluidics. We are grateful to all of the contributors for their efforts and to the referees, whose feedback has added value to every contribution. We hope you, as readers, will find benefit in the many ideas discussed in this Focus on Micro- and Nanofluidics, which represents a sampling of current activity, including experiment, simulation and theory, in this rapidly developing field. Focus on Micro- and Nanofluidics Content

  18. A sharp-focusing schlieren optical deflectometer

    NASA Technical Reports Server (NTRS)

    Alvi, F. S.; Settles, G. S.; Weinstein, L. M.

    1993-01-01

    A new instrument capable of localized, nonintrusive turbulence measurements is developed by combining a focusing schlieren system with an optical deflectometer. This instrument records the fluctuating light intensity at a point in the focused schlieren image. Its capability is verified by making benchmark measurements of Kelvin-Helmholtz vortices produced in a low-speed axisymmetric mixing layer. The sharp-focusing effect is demonstrated both visually and quantitatively. The results show that the instrument is capable of optical turbulence measurements within a 4 mm depth-of-field.

  19. Designing focusing solenoids for superconducting RF accelerators

    SciTech Connect

    Davis, G.; Kashikhin, V.V.; Page, T.; Terechkine, I.; Tompkins, J.; Wokas, T.; /Fermilab

    2006-08-01

    The design of a focusing solenoid for use in a superconducting RF linac requires resolving a range of problems with conflicting requirements. Providing the required focusing strength contradicts the goal of minimizing the stray field on the surfaces of adjacent superconducting RF cavities. The requirement of a compact solenoid, able to fit into a gap between cavities, contradicts the need of mechanical support necessary to restrain electromagnetic forces that can result in coil motion and subsequent quenching. In this report we will attempt to address these and other issues arising during the development of focusing solenoids. Some relevant test data will also be presented.

  20. Focused ion beam source method and apparatus

    DOEpatents

    Pellin, Michael J. (Naperville, IL); Lykke, Keith R. (Gaithersburg, MD); Lill, Thorsten B. (Sunnyvale, CA)

    2000-01-01

    A focused ion beam having a cross section of submicron diameter, a high ion current, and a narrow energy range is generated from a target comprised of particle source material by laser ablation. The method involves directing a laser beam having a cross section of critical diameter onto the target, producing a cloud of laser ablated particles having unique characteristics, and extracting and focusing a charged particle beam from the laser ablated cloud. The method is especially suited for producing focused ion beams for semiconductor device analysis and modification.

  1. Aerodynamic Focusing Of High-Density Aerosols

    SciTech Connect

    Ruiz, D. E.; Fisch, Nathaniel

    2014-02-24

    High-density micron-sized particle aerosols might form the basis for a number of applications in which a material target with a particular shape might be quickly ionized to form a cylindrical or sheet shaped plasma. A simple experimental device was built in order to study the properties of high-density aerosol focusing for 1#22; m silica spheres. Preliminary results recover previous findings on aerodynamic focusing at low densities. At higher densities, it is demonstrated that the focusing properties change in a way which is consistent with a density dependent Stokes number.

  2. Self-focusing of a focused femtosecond laser pulse in air

    Microsoft Academic Search

    Y. E. Geints; A. A. Zemlyanov

    2010-01-01

    The regularities of self-focusing and filamentation of spatially focused ultra-short laser radiation in air are theoretically\\u000a considered. The relationship between beam focusing sharpness and effective characteristics of the filamentation zone is investigated.\\u000a The formation of ‘narrow’ and ‘wide’ light filaments compared to that of collimated radiation filamentation, upon high-power\\u000a focused laser pulse propagation, is established.

  3. Angelo Tsagarakis Business Academic focus International Marketing

    E-print Network

    Escher, Christine

    Academic achievement Pac-10 All-Academic squad,honorable mention > Volunteerism and leadership MotivationalAngelo Tsagarakis Business Academic focus International Marketing "I use basketball as a metaphor

  4. Attention: feedback focuses a wandering mind

    PubMed Central

    Awh, Edward; Vogel, Edward K

    2015-01-01

    Neurofeedback that tracks attentional focus in real time using fMRI and alerts subjects to impending lapses by modulating the difficulty of the task itself has been demonstrated to improve behavioral performance. PMID:25710832

  5. The plasma focus as a thruster 

    E-print Network

    Hardy, Richard Lee

    2005-02-17

    The need for low propellant weight, high efficiency propulsion systems is a glaring need for various space missions. This thesis presents the thrust modeling of the Dense Plasma Focus plasma motion phases. It also contrasts some of the engineering...

  6. Focusing Internet Searches for World Music Resources

    ERIC Educational Resources Information Center

    Mishra, Jennifer

    2004-01-01

    Discusses the importance of focusing Internet searches for world music resources. Importance of teaching about music from various cultures; Benefits of identifying a characteristic instrument by name or stylistic terms; Types of music web sites.

  7. Micro free-flow isoelectric focusing

    E-print Network

    Albrecht, Jacob William

    2008-01-01

    To unravel the complexity of cellular systems, protein prefractionation tools can be used to reduce cell lysate complexity and increase assay sensitivity. Rapid free flow isoelectric focusing (FF-IEF) is achieved in a ...

  8. HST Cycle 21 Focus and Optical Monitor

    NASA Astrophysics Data System (ADS)

    Cox, Colin

    2013-10-01

    This program is the Cycle 21 implementation of the HST Optical Monitoring Program. The 9 orbits comprising this proposal will utilize ACS {Wide Field channel} and WFC3 {UVIS channel} to observe stellar cluster members in parallel with multiple exposures over an orbit. Phase retrieval performed on the PSF in each image will be used to measure primarily focus, with the ability to explore apparent coma, astigmatism, and third order spherical changes in WFC3. The goals of this program are to:1.} monitor the overall OTA focal length for the purposes of maintaining focus within science tolerances.2.} gain experience with the relative effectiveness of phase retrieval on WFC3/UVIS PSFs.3.} determine focus offset between the imagers and identify any SI-specific focus behavior and dependencies.If need is determined, future visits will be modified to interleave WFC3/IR channel and STIS/CCD focii measurements.

  9. HST Cycle 19 Focus and Optical Monitor

    NASA Astrophysics Data System (ADS)

    Cox, Colin

    2011-10-01

    This program is the Cycle 18 implementation of the HST Optical Monitoring Program. The 12 orbits comprising this proposal will utilize ACS {Wide Field channel} and WFC3 {UVIS channel} to observe stellar cluster members in parallel with multiple exposures over an orbit. Phase retrieval performed on the PSF in each image will be used to measure primarily focus, with the ability to explore apparent coma, astigmatism, and third order spherical changes in WFC3. The goals of this program are to:1.} monitor the overall OTA focal length for the purposes of maintaining focus within science tolerances.2.} gain experience with the relative effectiveness of phase retrieval on WFC3/UVIS PSFs.3.} determine focus offset between the imagers and identify any SI-specific focus behavior and dependencies.If need is determined, future visits will be modified to interleave WFC3/IR channel and STIS/CCD focii measurements.

  10. HST Cycle 20 Focus and Optical Monitor

    NASA Astrophysics Data System (ADS)

    Cox, Colin

    2012-10-01

    TBDThis program is the Cycle 20 implementation of the HST Optical Monitoring Program. The 11 orbits comprising this proposal will utilize ACS {Wide Field channel} and WFC3 {UVIS channel} to observe stellar cluster members in parallel with multiple exposures over an orbit. Phase retrieval performed on the PSF in each image will be used to measure primarily focus, with the ability to explore apparent coma, astigmatism, and third order spherical changes in WFC3. The goals of this program are to:1.} monitor the overall OTA focal length for the purposes of maintaining focus within science tolerances.2.} gain experience with the relative effectiveness of phase retrieval on WFC3/UVIS PSFs.3.} determine focus offset between the imagers and identify any SI-specific focus behavior and dependencies.If need is determined, future visits will be modified to interleave WFC3/IR channel and STIS/CCD focii measurements.

  11. HST Cycle 18 Focus and Optical Monitor

    NASA Astrophysics Data System (ADS)

    Cox, Colin

    2010-09-01

    This program is the Cycle 18 implementation of the HST Optical Monitoring Program. The 12 orbits comprising this proposal will utilize ACS {Wide Field channel} and WFC3 {UVIS channel} to observe stellar cluster members in parallel with multiple exposures over an orbit. Phase retrieval performed on the PSF in each image will be used to measure primarily focus, with the ability to explore apparent coma, astigmatism, and third order spherical changes in WFC3. The goals of this program are to:1.} monitor the overall OTA focal length for the purposes of maintaining focus within science tolerances.2.} gain experience with the relative effectiveness of phase retrieval on WFC3/UVIS PSFs.3.} determine focus offset between the imagers and identify any SI-specific focus behavior and dependencies.If need is determined, future visits will be modified to interleave WFC3/IR channel and STIS/CCD focii measurements.

  12. Focus Issue: A Niche of One's Own

    NSDL National Science Digital Library

    Elizabeth M. Adler (American Association for the Advancement of Science; Science Signaling REV)

    2008-05-27

    In this Focus Issue of Science Signaling, which complements the Science Special Issue on Microbial Ecology (http://www.sciencemag.org/microbialecology/), we explore signaling mechanisms whereby microbes—both benign and pathogenic—interact with their hosts.

  13. A Week-Long Focus on Development.

    ERIC Educational Resources Information Center

    Miller, Stuart; Ross, Judy

    1999-01-01

    Presents a way to dispel common misconceptions about the Third World by organizing a schoolwide event that focuses on the successes of people in developing nations, and the lessons students can learn from their experiences and achievements. (CCM)

  14. Hydrodynamic focusing of a particle flux

    SciTech Connect

    Makhviladze, G.M.; Melikhov, O.I.; Nikolova, I.P. [Institute of Mechanics and Biomechanics, Sofia (Bulgaria)

    1995-12-01

    Based on numerical integration of the equations of mechanics of multiphase media, an effect of focusing of a particle flux generated by a source located on the upper wall of a closed vessel has been revealed and investigated.

  15. Regulatory focus and attitudes to migrants

    Microsoft Academic Search

    Jennifer Whelan; Simon M. Laham; Kim Peters; Jennifer Boldero; Yoshihisa Kashima

    2010-01-01

    In two studies we examined the role of two regulatory foci (i.e., prevention and promotion) in predicting Australian's attitudes to different types of migrants. According to regulatory focus theory, promotion-focused self-regulation is concerned with nurturance and accomplishment needs and involves the pursuit of wishes and aspirations. As such, it results in sensitivity to positive outcomes and to relative pleasure from

  16. Depression and self-focused attention

    Microsoft Academic Search

    Timothy W. Smith; Jeff Greenberg

    1981-01-01

    Recent research on self-focused attention has indicated effects that parallel several cognitive and affective phenomena associated with depression. Specifically, discrepancies between perceived real and ideal self, increased affective response, self-attribution for negative events, and accurate self-reports occur both in depression and as a result of self-focused attention. A study is reported that investigated the relationship between depression and a measure

  17. A figure of merit for focusing metasurfaces

    NASA Astrophysics Data System (ADS)

    Saeidi, Chiya; van der Weide, Daniel

    2015-03-01

    We propose and define a figure of merit (FoM) for designing focusing metasurfaces by establishing a reference case. We emphasize the important role of the focal point concept for obtaining the desired functionality. We suggest several design considerations along with the FoM for a careful design and performance evaluation of the prototype, without which the focusing property of a designed metasurface may be only slightly better than that of a planar scattering surface.

  18. Acoustically Focused Oceanographic Sampling in Coastal Environments

    Microsoft Academic Search

    Henrik Schmidt; James G. Bellingham; Pierre Elisseeff

    1997-01-01

    A new oceanographic measurement concept, AcousticallyFocused Ocean Sampling - AFOS, is presented,combining a tomographic network with small autonomousunderwater vehicles. Using wireless local area networktechnology, the acoustic tomography data are recordedand processed in real time for achieving a low-resolutionestimate of oceanographic parameters. The results areused to focus direct measurements by a network of smallAUV's in areas of high spatial and temporal

  19. A Framework for Focus+Context Visualization

    Microsoft Academic Search

    Staffan Björk; Lars Erik Holmquist; Johan Redström

    1999-01-01

    Focus+context visualization techniques aim to give users integrated visual access to both details and overview of a data set. This paper gives a systematic account of such visualization techniques. We introduce the notion that there are different levels of information visualization, with focus+context being a second-level visualization, and illustrate this with examples. We then provide a formal framework for describing

  20. The final focus test beam project

    SciTech Connect

    Burke, D.

    1991-05-01

    An overview is given of the Final Focus Test Beam (FFTB) that is being constructed as a prototype final focus system for a future electron-positron linear collider. This beam line will use as input the 50 GeV electron beam from the SLC linac, and is designed to reduce the transverse dimensions of the beam spot at the focal point to 1 {mu}m. 5 refs., 2 figs., 1 tab.

  1. Efficacy of Child-Focused and Parent-Focused Interventions in a Child Anxiety Prevention Study

    ERIC Educational Resources Information Center

    Simon, Ellin; Bogels, Susan Maria; Voncken, Jannie Marisol

    2011-01-01

    This study examined anxiety development in median- (n = 74) and high-anxious children (n = 183) aged 8-13, the effect of parent- and child-focused preventive interventions on child/parental anxiety, and the effect of parental anxiety on child anxiety. High-anxious children were randomized into a parent-focused (n = 69), child-focused (n = 58) or…

  2. Focus-distance-controlled 3D TV

    NASA Astrophysics Data System (ADS)

    Yanagisawa, Nobuaki; Kim, Kyung-tae; Son, Jung-Young; Murata, Tatsuya; Orima, Takatoshi

    1997-05-01

    There is a phenomenon that a 3D image appears in proportion to a focus distance when something is watched through a convex lens. An adjustable focus lens which can control the focus distance of the convex lens is contrived and applied to 3D TV. We can watch 3D TV without eyeglasses. The 3D TV image meets the NTSC standard. A parallax data and a focus data about the image can be accommodated at the same time. A continuous image method realizes much wider views. An anti 3D image effect can be avoided by using this method. At present, an analysis of proto-type lens and experiment are being carried out. As a result, a phantom effect and a viewing area can be improved. It is possible to watch the 3D TV at any distance. Distance data are triangulated by two cameras. A plan of AVI proto type using ten thousands lenses is discussed. This method is compared with four major conventional methods. As a result, it is revealed that this method can make the efficient use of integral photography and varifocal type method. In the case of integral photography, a miniaturization of this system is possible. But it is difficult to get actual focus. In the case of varifocal type method, there is no problem with focusing, but the miniaturization is impossible. The theory investigated in this paper makes it possible to solve these problems.

  3. Focus-distance-controlled 3D TV

    NASA Astrophysics Data System (ADS)

    Yanagisawa, Nobuaki; Kim, Kyung-tae; Son, Jung-Young; Murata, Tatsuya; Orima, Takatoshi

    1996-09-01

    There is a phenomenon that a 3D image appears in proportion to a focus distance when something is watched through a convex lens. An adjustable focus lens which can control the focus distance of the convex lens is contrived and applied to 3D TV. We can watch 3D TV without eyeglasses. The 3D TV image meets the NTSC standard. A parallax data and a focus data about the image can be accommodated at the same time. A continuous image method realizes much wider views. An anti 3D image effect can be avoided by using this method. At present, an analysis of proto-type lens and experiment are being carried out. As a result, a phantom effect and a viewing area can be improved. It is possible to watch the 3D TV at any distance. Distance data are triangulated by two cameras. A plan of AVI photo type using ten thousand lenses is discussed. This method is compared with four major conventional methods. As a result, it is revealed that this method can make the efficient use of Integral Photography and Varifocal type method. In the case of Integral Photography, a miniaturization of this system is possible. But it is difficult to get actual focus. In the case of varifocal type method, there is no problem with focusing, but the miniaturization is impossible. The theory investigated in this paper makes it possible to solve these problems.

  4. Capillary isoelectric focusing of native and inactivated microorganisms.

    PubMed

    Horká, M; Kubícek, O; R?zicka, F; Holá, V; Malinovská, I; Slais, K

    2007-07-01

    The research of microorganisms includes the development of methods for the inactivation of viruses and other microbes. It also means to efficiently eliminate the infectivity of microorganisms without damage of their integrity and structure. According to the results of the last 5 years the capillary electromigration techniques appear to be very perspective for the comparison of the methods applicable for inactivation in the diagnostics and study of the pathogens. In this paper we suggest the capillary isoelectric focusing of the model microorganisms, Escherichia coli, Staphylococcus epidermidis, Candida albicans and bacteriophage PhiX 174, native or inactivated by different procedures. UV detection and fluorometric detection for the dynamically modified microbes by pyrenebutanoate on the basis of the non-ionogenic tenside were used here. Isoelectric points of native and/or dynamically modified microorganisms and other properties were compared with those obtained after microorganisms inactivation. The segmental injection of the sample pulse enabled the reproducible and efficient capillary isoelectric focusing in different pH gradients. The low-molecular-weight pI markers were used for tracing of the pH gradient. PMID:17328903

  5. Onset Detection in Musical Audio Signals

    Microsoft Academic Search

    Stephen Hainsworth; Malcolm Macleod

    2003-01-01

    This paper presents work on changepoint detection in musi- cal audio signals, focusing on the case where there are note changes with low associated energy variation. Several meth- ods are described and results of the best are presented.

  6. Word Detectives.

    ERIC Educational Resources Information Center

    Ainslie, Dodie

    2001-01-01

    Outlines a vocabulary strategy that transforms students into "word detectives," while immersing them in reading and encouraging them to find out the meaning of unknown words. Describes how "lead detectives" use graphic organizers, briefings on word "suspects," and notes several extensions to this activity. (SR)

  7. Fingerprint detection

    Microsoft Academic Search

    George C

    1992-01-01

    A method for detection and visualization of latent fingerprints is provided and includes contacting a substrate containing a latent print thereon with a colloidal metal composition for time sufficient to allow reaction of said colloidal metal composition with said latent print, and preserving or recording the observable print. Further, the method for detection and visualization of latent fingerprints can include

  8. Bat Detective

    NSDL National Science Digital Library

    2014-05-14

    Bat Detective is an online citizen science project which allows visitors to the website to take part in wildlife conservation by listening out for bat calls in recordings collected all over the world. By sorting the sounds in the recordings into insect and bat calls, bat detectives will help biologists learn how to reliably distinguish bat 'tweets' to develop new automatic identification tools.

  9. Avalanche photodiode detection statistics for direct detection laser radar

    Microsoft Academic Search

    Douglas G. Youmans

    1992-01-01

    The detection statistics of avalanche photodiode detectors when used in laser radar systems are examined. In the laser radar systems considered here, a diffuse hard target is illuminated by a transmitted laser beam and the photons subtended by the receiving aperture and focused onto the detector obey negative-binomial statistics. The specific negative-binomial distribution is determined by the coherence length of

  10. (Aerodynamic focusing of particles and heavy molecules)

    SciTech Connect

    de la Mora, J.F.

    1990-01-08

    By accelerating a gas containing suspended particles or large molecules through a converging nozzle, the suspended species may be focused and therefore used to write fine lines on a surface. Our objective was to study the limits on how narrow this focal region could be as a function of particle size. We find that, for monodisperse particles with masses m{sub p} some 3.6 {times} 10{sup 5} times larger than the molecular mass m of the carrier gas (diameters above some 100{angstrom}), there is no fundamental obstacle to directly write submicron features. However, this conclusion has been verified experimentally only with particles larger than 0.1 {mu}m. Experimental, theoretical and numerical studies on the defocusing role of Brownian motion for very small particles or heavy molecules have shown that high resolution (purely aerodynamic) focusing is impossible with volatile molecules whose masses are typically smaller than 1000 Dalton. For these, the minimal focal diameter after optimization appears to be 5{radical}(m/m{sub p}) times the nozzle diameter d{sub n}. But combinations of focused lasers and aerodynamic focusing appear as promising for direct writing with molecular precursors. Theoretical and numerical schemes capable of predicting the evolution of the focusing beam, including Brownian motion effects, have been developed, although further numerical work would be desirable. 11 refs.

  11. An Rf Focused Interdigital Ion Accelerating Structure

    SciTech Connect

    Swenson, D.A. [Linac Systems, Albuquerque, NM 87122 (United States)

    2003-08-26

    An Rf Focused Interdigital (RFI) ion accelerating structure will be described. It represents an effective combination of the Wideroee (or interdigital) linac structure, used for many low frequency, heavy ion applications, and the rf electric quadrupole focusing used in the RFQ and RFD linac structures. As in the RFD linac structure, rf focusing is introduced into the RFI linac structure by configuring the drift tubes as two independent pieces operating at different electrical potentials as determined by the rf fields of the linac structure. Each piece (or electrode) of the RFI drift tube supports two fingers pointed inwards towards the opposite end of the drift tube forming a four-finger geometry that produces an rf quadrupole field along the axis of the linac for focusing the beam. However, because of the differences in the rf field configuration along the axis, the scheme for introducing rf focusing into the interdigital linac structure is quite different from that adopted for the RFD linac structure. The RFI linac structure promises to have significant size, efficiency, performance, and cost advantages over existing linac structures for the acceleration of low energy ion beams of all masses (light to heavy). These advantages will be reviewed. A 'cold model' of this new linac structure has been fabricated and the results of rf cavity measurements on this cold model will be presented.

  12. Anomaly Detection over Noisy Data using Learned Probability Distributions

    Microsoft Academic Search

    Eleazar Eskin

    2000-01-01

    Traditional anomaly detection techniques focus on detecting anomalies in new data after training on normal (or clean) data. In this paper we present a technique for detecting anomalies without training on normal data. We present a method for detecting anomalies within a data set that contains a large number of normal elements and relatively few anomalies. We present a mixture

  13. Optimal detection and control strategies for invasive species management

    Microsoft Academic Search

    Shefali V. Mehta; Robert G. Haight; Frances R. Homans; Stephen Polasky; Robert C. Venette

    2007-01-01

    The increasing economic and environmental losses caused by non-native invasive species amplify the value of identifying and implementing optimal management options to prevent, detect, and control invasive species. Previous literature has focused largely on preventing introductions of invasive species and post-detection control activities; few have addressed the role of detection. By increasing resources to detect invasive species, managers may increase

  14. Car detection using Markov random fields on geometric features

    Microsoft Academic Search

    Xingzhi Chang; Liqun Gao

    2007-01-01

    Car detection is widely used in many vehicle management systems. Most of the car detection methods are focused on the top (aerial) or side images. Usually these methods are supervised detection which is complicated and need to use different kinds of classifiers and training data sets. This paper introduces a new unsupervised approach to provide fast car detection from rear

  15. Moving target focusing and parameter estimation based on ROI of multi-channel UWB SAR images

    Microsoft Academic Search

    Chang Yu-lin; Zhou Hong; Huang Xiao-tao; Zhou Zhi-min

    2008-01-01

    Image domain GMTI methods are very suitable for the multi-channel UWB SAR system. However, present image domain GMTI methods are mainly on the moving target detection and 1D range velocity estimation, but seldom refer to moving target focusing and 2D velocity\\/position parameter estimation. This paper proposes a new method for moving target focusing and parameter estimation based on the ROI

  16. EDITORIAL: Focus on High Energy Particle Astronomy FOCUS ON HIGH ENERGY PARTICLE ASTRONOMY

    NASA Astrophysics Data System (ADS)

    Ong, Rene A.; Covault, Corbin E.

    2009-05-01

    Astrophysics as a sub-discipline provides both unique opportunities and unique challenges relative to other fields of physics. On the one hand, the scope of astrophysics is literally universal, and we are free to examine the most interesting and exotic phenomena to be found anywhere. On the other hand, our access to the universe is limited to only those bits of information that nature happens to provide to us here on Earth. As astrophysicists, we have no direct control over our subject of study. We cannot conduct experiments to arrange stars in galaxies to our liking. We cannot initiate supernovas at specific times and places just to test our hypotheses. What we can do is to squeeze whatever information possible out of the the tiny particles that have traveled across vast distances to act as messengers to Earth from space. Fortunately, we are getting quite good at building a picture of the universe from the available astrophysical information. Nearly a decade into the millennium, scientists have deployed an impressive collection of sensitive observatories that are especially capable of unlocking the secrets of some of the most persistent astrophysical puzzles. In particular, in the fields of high-energy astrophysics corresponding to gamma-ray, cosmic ray and neutrino detection, we are moving to a new generation of experimental techniques that are dramatically more sensitive than prior efforts. These new instruments have two key properties: (1) increased collection area, which is critical for the low fluxes corresponding to high-energy messenger particles, and (2) precision directional reconstructions which allow observers to trace back the paths of these messengers to the originating astrophysical objects. Furthermore, as observational techniques mature, results from these complementary instruments provide an increasingly comprehensive picture of some of the more elusive astrophysical subjects. Each photon, cosmic ray, and neutrino result reported represents another clue to understanding the nature of high-energy objects both within and outside our galaxy. And yet, along with new understandings, we are also faced with new puzzles. Each of the papers in this focus issue presents the field of high-energy particle astronomy from the perspective of a given instrumental approach, corresponding to the current state-of-the-art for a particular class of messenger particle in a given energy range. For gamma-ray astronomy, we have a excellent report by R Johnson and R Mukherjee on results from space-borne telescopes, first from the Compton Gamma Ray Observatory and then from the recently commissioned Fermi Gamma-Ray Space Telescope. The detailed paper by J Hinton describes a wealth of results from several ground-based gamma-ray telescopes using the atmospheric Cherenokov technique. Gamma-ray results and the prospects from air-shower detectors which can provide all-sky monitoring are very well described in a paper by G Sinnis. Larger plans for the future of ground-based gamma-ray astronomy are summarized in a paper by F Krennrich (in preparation). We also include two papers for 'non-photon' particle detection, a summary of the exciting new results for cosmic ray physics by P Sommers and S Westerhoff and an article by K Hoffman describing the astrophysics and capabilities of truly remarkable, large-volume neutrino detectors. For both cosmic rays and neutrinos, the fields seem to be on the threshold of doing astronomy—that is, associating specific detected particles with particular astrophysical objects. Together, the fully operational space- and ground-based gamma-ray observatories and the new large-area experiments for cosmic ray and neutrino detection represent a new era in astronomy. We can be confident that the field of high-energy particle astronomy will continue to rapidly develop as more exciting results from these instruments are reported in the future. Focus on High Energy Particle Astronomy Contents Gamma ray astronomy with atmospheric Cherenkov telescopes: the future Frank Krennrich GeV telescopes: results and prospects

  17. High-intensity focused ultrasound monitoring using harmonic motion imaging for focused ultrasound (HMIFU) under boiling or slow denaturation conditions.

    PubMed

    Hou, Gary Y; Marquet, Fabrice; Wang, Shutao; Apostolakis, Iason-Zacharias; Konofagou, Elisa E

    2015-07-01

    Harmonic motion imaging for focused ultrasound (HMIFU) is a recently developed high-intensity focused ultrasound (HIFU) treatment monitoring method that utilizes an amplitude-modulated therapeutic ultrasound beam to induce an oscillatory radiation force at the HIFU focus and estimates the focal tissue displacement to monitor the HIFU thermal treatment. In this study, the performance of HMIFU under acoustic, thermal, and mechanical effects was investigated. The performance of HMIFU was assessed in ex vivo canine liver specimens (n = 13) under slow denaturation or boiling regimes. A passive cavitation detector (PCD) was used to assess the acoustic cavitation activity, and a bare-wire thermocouple was used to monitor the focal temperature change. During lesioning with slow denaturation, high quality displacements (correlation coefficient above 0.97) were observed under minimum cavitation noise, indicating the tissue initial-softeningthen- stiffening property change. During HIFU with boiling, HMIFU monitored a consistent change in lesion-to-background displacement contrast (0.46 ± 0.37) despite the presence of strong cavitation noise due to boiling during lesion formation. Therefore, HMIFU effectively monitored softening-then-stiffening during lesioning under slow denaturation, and detected lesioning under boiling with a distinct change in displacement contrast under boiling in the presence of cavitation. In conclusion, HMIFU was shown under both boiling and slow denaturation regimes to be effective in HIFU monitoring and lesioning identification without being significantly affected by cavitation noise. PMID:26168177

  18. Quasi In-Focus Optical Coherence Tomography

    NASA Astrophysics Data System (ADS)

    Ohmi, Masato; Kurata, Takayuki; Sekimoto, Mitsugu; Haruna, Masamitsu

    2004-02-01

    We propose here a unique method for in-focus imaging over the entire cross-sectional area of interest. This is the so-called quasi in-focus optical coherence tomography (OCT) or multiple OCT in which OCT images are obtained by shifting the focal plane of an objective, followed by piling up of these OCT images. A preliminary experiment was made using chicken tissue as a sample; as a result, a stripe pattern of fibrous muscle was clearly observed over a depth of more than 3 mm. In in-vitro tomographic imaging of the human stomach wall, quasi in-focus OCT can provide a very clear image of the muscularis mucosae, which is a bending film like tissue of a few tens of microns thickness, showing that our method is useful for the early-stage diagnosis of stomach cancer.

  19. Focused plasmonic trapping of metallic particles

    PubMed Central

    Min, Changjun; Shen, Zhe; Shen, Junfeng; Zhang, Yuquan; Fang, Hui; Yuan, Guanghui; Du, Luping; Zhu, Siwei; Lei, Ting; Yuan, Xiaocong

    2013-01-01

    Scattering forces in focused light beams push away metallic particles. Thus, trapping metallic particles with conventional optical tweezers, especially those of Mie particle size, is difficult. Here we investigate a mechanism by which metallic particles are attracted and trapped by plasmonic tweezers when surface plasmons are excited and focused by a radially polarized beam in a high-numerical-aperture microscopic configuration. This contrasts the repulsion exerted in optical tweezers with the same configuration. We believe that different types of forces exerted on particles are responsible for this contrary trapping behaviour. Further, trapping with plasmonic tweezers is found not to be due to a gradient force balancing an opposing scattering force but results from the sum of both gradient and scattering forces acting in the same direction established by the strong coupling between the metallic particle and the highly focused plasmonic field. Theoretical analysis and simulations yield good agreement with experimental results. PMID:24305554

  20. Remote adjustable focus Raman spectroscopy probe

    DOEpatents

    Schmucker, John E. (Hurt, VA); Blasi, Raymond J. (Harrison City, PA); Archer, William B. (Bethel Park, PA)

    1999-01-01

    A remote adjustable focus Raman spectroscopy probe allows for analyzing Raman scattered light from a point of interest external probe. An environmental barrier including at least one window separates the probe from the point of interest. An optical tube is disposed adjacent to the environmental barrier and includes a long working length compound lens objective next to the window. A beam splitter and a mirror are at the other end. A mechanical means is used to translated the prove body in the X, Y, and Z directions resulting in a variable focus optical apparatus. Laser light is reflected by the beam splitter and directed toward the compound lens objective, then through the window and focused on the point of interest. Raman scattered light is then collected by the compound lens objective and directed through the beam splitter to a mirror. A device for analyzing the light, such as a monochrometer, is coupled to the mirror.

  1. Attentional focus in complex skill learning.

    PubMed

    Wulf, G; McNevin, N H; Fuchs, T; Ritter, F; Toole, T

    2000-09-01

    Experiment 1 examined whether it is more advantageous to direct learners' attention to the external effects of their movements relative to other external cues. Two groups of participants hit tennis balls at a target, with one group focusing on the ball coming toward them (antecedent) and the other group focusing on the ball leaving the racket (effect). The effect group demonstrated more effective learning. Experiment 2 examined whether it is more beneficial if the movement effect is related to the movement technique, relative to other movement effects (e.g., outcome). Two groups of participants hit golf balls at a target. The attention of these groups was directed to the club or the ball trajectory, respectively. The club group showed more effective learning than the target group, suggesting that focusing on technique-related effects is more effective. PMID:10999260

  2. Remote Adjustable focus Raman Spectroscopy Probe

    SciTech Connect

    Schmucker, John E.; Blasi, Raymond J.; Archer, William B.

    1998-07-28

    A remote adjustable focus Raman spectroscopy probe allows for analyzing Raman scattered light from a point of interest external to the probe. An environmental barrier including at least one window separates the probe from the point of interest. An optical tube is disposed adjacent to the environmental barrier and includes along working length compound lens objective next to the window. A beam splitter and a mirror are at the other end. A mechanical means is used to translate the probe body in the X, Y, and Z directions resulting in a variable focus optical apparatus. Laser light is reflected by the beam splitter and directed toward the compound lens objective, then through the window and focused on the point of interest. Raman scattered light is then collected by the compound lens objective and directed through the beam splitter to a mirror. A device for analyzing the light, such as a monochrometer, is coupled to the mirror.

  3. [Identification of a new focus of schistosoma mansoni. (Municipality of Nova Lima, MG, Brazil].

    PubMed

    Guerra, H L; Guimarães, C T; França, M A; Rocha, R S; Katz, N

    1991-01-01

    The detection of a new transmission focus of schistosomiasis in Nova Lima town, Minas Gerais State, Brazil, is reported. The search of snail intermediate hosts in Banqueta do Bananal a small locality of Boa Vista neighbourhood detected 356 specimens of Biomphalaria glabrata, with a infection rate of 8.4%. In hundred-sixty-two patients stool examinations (Kato-Katz method) were done, showing ninety-one patients with eggs of Schistosoma mansoni in their feces. The integrated action of local residents and the local administration resulted in the elimination of the focus. PMID:1842844

  4. Capillary Isoelectric Focusing Immunoassay for Fat Cell Differentiation Proteomics

    PubMed Central

    Johlfs, Mary G.; Gorjala, Priyatham; Urasaki, Yasuyo; Le, Thuc T.; Fiscus, Ronald R.

    2015-01-01

    Profiling cellular proteome is critical to understanding signal integration during cell fate determination. In this study, the capability of capillary isoelectric focusing (cIEF) immunoassays to detect post-translational modifications (PTM) of protein isoforms is demonstrated. cIEF immunoassays exhibit protein detection sensitivity at up to 5 orders of magnitude higher than traditional methods. This detection ultra-sensitivity permits proteomic profiling of several nanograms of tissue samples. cIEF immunoassays are employed to simultaneously profile three protein kinases during fat cell differentiation: cGMP-dependent protein kinase type I (PKG-I) of the nitric oxide (NO) signaling pathway, protein kinase B (Akt) of the insulin signaling pathway, and extracellular signal-regulated kinase (ERK) of the mitogen-activated protein kinase (MAPK) signaling pathway. Interestingly, a switch in the expression level of PKG- isoforms is observed during fat cell differentiation. While both PKG-I? and PKG-I? isoforms are present in preadipocytes, only PKG-I? isoform is expressed in adipocytes. On the other hand, the phosphorylation level increases for Akt while decreases for ERK1 and ERK2 following the maturation of preadipocytes into adipocytes. Taken together, cIEF immunoassay provides a highly sensitive means to study fat cell differentiation proteomics. cIEF immunoassay should be a powerful proteomics tool to study complex protein signal integration in biological systems. PMID:26132171

  5. Crystal diffraction lens telescope for focusing nuclear gamma rays

    SciTech Connect

    Smither, R.K.; Fernandez, P.B.; Graber, T. [Argonne National Lab., IL (United States). Advanced Photon Source; Ballmoos, P. von; Naya, J.; Albernhe, F.; Vedrenne, G. [Centre d`Etude Spatiale des Rayonnements, Toulouse (France); Faiz, M. [KFUPM, Dhahran (Saudi Arabia). Physics Dept.

    1996-08-01

    A crystal diffraction lens was constructed at Argonne National Laboratory for use as a telescope to focus nuclear gamma rays. It consisted of 600 single crystals of germanium arranged in 8 concentric rings. The mounted angle of each crystal was adjusted to intercept and diffract the incoming gamma rays with an accuracy of a few arc sec. The performance of the lens was tested in two ways. In one case, the gamma rays were focused on a single medium size germanium detector. In the second case, the gamma rays were focused on the central germanium detector of a 3 x 3 matrix of small germanium detectors. The efficiency, image concentration and image quality, and shape were measured. The tests performed with the 3 x 3 matrix detector system were particularly interesting. The wanted radiation was concentrated in the central detector. The 8 other detectors were used to detect the Compton scattered radiation, and their energy was summed with coincident events in the central detector. This resulted in a detector with the efficiency of a large detector (all 9 elements) and the background of a small detector (only the central element). The use of the 3 x 3 detector matrix makes it possible to tell if the source is off axis and, if so, to tell in which direction. The crystal lens acts very much like a simple convex lens for visible light. Thus if the source is off to the left then the image will focus off to the right illuminating the detector on the right side: telling one in which direction to point the telescope. Possible applications of this type of crystal lens to balloon and satellite experiments will be discussed.

  6. Improved Large-Field Focusing Schlieren System

    NASA Technical Reports Server (NTRS)

    Weinstein, Leonard M.

    1993-01-01

    System used to examine complicated two- and three-dimensional flows. High-brightness large-field focusing schlieren system incorporates Fresnel lens instead of glass diffuser. In system with large field of view, image may also be very large. Relay optical subsystem minifies large image while retaining all of light. Facilities candidates for use of focusing schlieren include low-speed wind and water tunnels. Heated or cooled flow tracers or injected low- or high-density tracers used to make flows visible for photographic recording.

  7. Light focusing in the Anderson Regime

    E-print Network

    Leonetti, Marco; Mafi, Arash; Conti, Claudio

    2014-01-01

    Anderson localization is a regime in which diffusion is inhibited and waves (also electromagnetic waves) get localized. Here we exploit adaptive optics to achieve focusing in disordered optical fibers in the Anderson regime. By wavefront shaping and optimization, we observe the generation of a propagation invariant beam, where light is trapped transversally by disorder, and show that Anderson localizations can be also excited by extended speckled beams. We demonstrate that disordered fibers allow a more efficient focusing action with respect to standard fibers in a way independent of their length, because of the propagation invariant features and cooperative action of transverse localizations.

  8. Light focusing in the Anderson regime

    NASA Astrophysics Data System (ADS)

    Leonetti, Marco; Karbasi, Salman; Mafi, Arash; Conti, Claudio

    2014-07-01

    Anderson localization is a regime in which diffusion is inhibited and waves (also electromagnetic waves) get localized. Here we exploit adaptive optics to achieve focusing in disordered optical fibres in the Anderson regime. By wavefront shaping and optimization, we observe the generation of a propagation-invariant beam, where light is trapped transversally by disorder, and show that Anderson localizations can be also excited by extended speckled beams. We demonstrate that disordered fibres allow a more efficient focusing action with respect to standard fibres in a way independent of their length, because of the propagation-invariant features and cooperative action of transverse localizations.

  9. Focusing Ultrasound with Acoustic Metamaterial Network

    E-print Network

    Zhang, Shu; Fang, Nicholas

    2009-01-01

    We present the first experimental demonstration of focusing ultrasound waves through a flat acoustic metamaterial lens composed of a planar network of subwavelength Helmholtz resonators. We observed a tight focus of half-wavelength in width at 60.5 KHz by imaging a point source. This result is in excellent agreement with the numerical simulation by transmission line model in which we derived the effective mass density and compressibility. This metamaterial lens also displays variable focal length at different frequencies. Our experiment shows the promise of designing compact and light-weight ultrasound imaging elements.

  10. Photoelectric automatic focusing system based on interference

    NASA Astrophysics Data System (ADS)

    Liu, T. G.; Cai, H. Y.; Zhang, F. L.; Lessard, R. A.; Zhang, Y. M.

    2001-10-01

    The principle and the method of a new automatic focusing system are presented in this paper. The system is constructed relying on the relationship between laser wave interference patterns and defocusing displacement. A CCD linear array receives interference patterns in the form of light intensity, which are converted into digital signals afterwards. Then the computer controls a stepping motor to complete auto-focusing process according to the digital results. The system has been applied in a kind of film resolution testing instrument and it shows that it has the advantage of high accuracy, high speed and wide applications.

  11. Ion heating in a plasma focus

    NASA Technical Reports Server (NTRS)

    Hohl, F.; Gary, S. P.

    1974-01-01

    Ion acceleration and heating in a plasma focus were investigated by the numerical integration of the three-dimensional equations of motion. The electric and magnetic fields given were derived from experimental data. The results obtained show that during the collapse phase of focus formation, ions are efficiently heated to temperatures of several keV. During the phase of rapid current reduction, ions are accelerated to large velocities in the axial direction. The results obtained with the model are in general agreement with experimental results.

  12. Plasma focus: Present status and potential applications

    SciTech Connect

    Brzosko, J.S.; Nardi, V.; Powell, C. [Avogadro Energy Systems, Inc., Staten Island, NY (United States)

    1997-12-01

    Initially, dense plasma focus (DPF) machines were constructed independently by Filippov in Moscow and Mather in Los Alamos at the end of the 1950s. Since then, more than 30 laboratories have carried vigorous DPF programs, oriented mainly toward the studies of physics of ion acceleration and trapping in the plasma focus environment. Applications of the DPF as intense neutron and X-ray sources have been recognized since its discovery but not implemented for various reasons. Recently, some groups (including AES) addressed the issue of DPF applications, and some of them are briefly discussed in this paper.

  13. Final Focus Test Stand final report

    E-print Network

    Jeremie, A; Burrows, P

    2013-01-01

    Future Linear colliders will need particle beam sizes in the nanometre range. The beam also needs to be stable all along the beam line and especially at the Final Focus section. A dedicated Final Focus test stand has been used for this study and is comprised of several sub-parts. First there is the Stabilisation/Isolation system with sensors and actuators stabilizing down to sub-nanometre level. Then the Magnet itself needs to comply with very specific design constraints. In addition to the mechanical items, the beam can be stabilized acting on the trajectory directly and Beam-based controls have been developed and tested on different accelerator facilities.

  14. The changing focus of marine mammal conservation.

    PubMed

    Hofman, R J

    1995-11-01

    Overexploitation has been the principal focus of marine mammal conservation. Less attention has been paid to bycatch in commercial fisheries; entanglement in lost and discarded fishing gear; food shortages owing to climate change and/or overharvesting of essential prey; point and non-point source pollution; and diseases. Also, relatively little attention has been paid to situations where marine mammals pose threats to the existence and human uses of other marine species. As overexploitation is addressed, focus must be shifted to these problems that are no less significant. PMID:21237105

  15. Methods and Strategies: Concept-Focused Teaching

    NSDL National Science Digital Library

    Joanne K. Olson

    2008-12-01

    One of the main problems we face in science teaching is that students are learning isolated facts and missing central concepts. For instance, consider what you know about life cycles. Chances are that you remember something about butterflies and stages, such as egg, larva, pupa, adult. But what's the take-home idea that we should have learned about life cycles? Do students really need to know "egg, larva, pupa, adult?" An important way to address this is to remain focused on the central concept--i.e., the big ideas--rather than topic-focused teaching.

  16. SKEW QUADRUPOLE FOCUSING LATTICES AND APPLICATIONS.

    SciTech Connect

    PARKER,B.

    2001-06-18

    In this paper we revisit using skew quadrupole fields in place of traditional normal upright quadrupole fields to make beam focusing structures. We illustrate by example skew lattice decoupling, dispersion suppression and chromatic correction using the neutrino factory Study-II muon storage ring design. Ongoing BNL investigation of flat coil magnet structures that allow building a very compact muon storage ring arc and other flat coil configurations that might bring significant magnet cost reduction to a VLHC motivate our study of skew focusing.

  17. Ionospheric Estimation and Integrity Threat Detection

    E-print Network

    Stanford University

    Ionospheric Estimation and Integrity Threat Detection Andrew J. Hansen Todd Walter Y.C. Chao Per is focused on ionospheric estimation using tomographic inversion and integrity monitoring of WAAS ionospheric currently focuses on the study of GPS dual-frequency measure- ment calibration, WAAS ionospheric modeling

  18. Ovulation Detection

    MedlinePLUS

    ... URL www.asrm.org PATIENT’S FACT SHEET Ovulation Detection Ovulation, the release of an egg from its ... cycles, an ovulatory problem may be present. Transvaginal Ultrasound. Follicular growth can be measured with ultrasound, a ...

  19. Quality control of murine monoclonal antibodies using isoelectric focusing affinity immunoblot analysis

    NASA Technical Reports Server (NTRS)

    Hamilton, Robert G.; Rodkey, L. Scott; Reimer, Charles B.

    1987-01-01

    The quality control of murine hybridoma secretory products has been performed using two approaches for isoelectric focusing affinity immunoblot analysis: (1) a method in which antigen-coated nitrocellulose is placed on top of an acrylamide gel containing isoelectrically focused ascites to bind the antigen specific monoclonal antibody; and (2) a method in which focused ascite proteins were passively blotted onto nitrocellulose and specific monoclonal antibodies were detected with enzyme-conjugated antigen. Analysis by both methods of batches of ascites containing antihuman IgG antibodies that were produced by six hybridomas permitted effective monitoring of immunoreactive antibodies for pI microheterogeneity.

  20. Dark Matter: Direct Detection

    SciTech Connect

    Chardin, G. [CSNSM, CNRS/IN2P3 and Universite Paris-Sud, Orsay (France)

    2009-12-16

    The identification of Dark Matter is an outstanding question of contemporary physics. I summarize the main experimental strategies developed to answer this question, focusing on cryogenic detectors and comparing these detectors to their double-phase xenon and argon competitors. I discuss in particular the main developments in charge-phonon (CDMS, EDELWEISS) and light-phonon detectors (CRESST, ROSEBUD). Finally, I discuss the prospects of WIMP detection within the next few years by the CDMS, CRESST, EDELWEISS and XENON experiments, and their successors EURECA, GEODM and XENON-1 ton.

  1. Draft Detectives

    NSDL National Science Digital Library

    Sciencenter

    2010-01-01

    In this two part activity, learners become draft detectives by constructing their own draft catchers to detect drafts around windows or doors. Next, they make draft stoppers to reduce air flow and conserve energy. This activity helps learners understand the importance of reducing drafts and preventing heat or cold air loss. Note: the second part of this activity requires the use of a sewing machine (not included in cost of materials).

  2. Focusing polychromatic light through strongly scattering media

    E-print Network

    . Lu, J. Moore, S. Hoffman, R. Paxman, K. Toussaint, and T. Bifano, "Focusing through dynamic. Toussaint, Jr., "Vector transmission matrix for the polarization behavior of light propagation in highly at visible wavelengths," Nat Commun 3, 889 (2012). 16. J. W. Goodman, Speckle Phenomena in Optics (Roberts

  3. Using Machine Learning to Focus Iterative Optimization

    Microsoft Academic Search

    Felix V. Agakov; Edwin V. Bonilla; John Cavazos; Björn Franke; Grigori Fursin; Michael F. P. O'boyle; John Thomson; Marc Toussaint; Christopher K. I. Williams

    2006-01-01

    Iterative compiler optimization has been shown to out- perform static approaches. This, however, is at the cost of large numbers of evaluations of the program. This paper de- velops a new methodology to reduce this number and hence speed up iterative optimization. It uses predictive modelling from the domain of machine learning to automatically focus search on those areas likely

  4. Dropout Prevention & Attrition Rates. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1994

    1994-01-01

    This newsletter contains six articles focusing on dropouts, potential dropouts, dropout rates, and dropout prevention, particularly in Texas and among Hispanics and other minority groups. "Improving Student Performance: Study Identifies Better Approach" (Maria Robledo Montecel, Josie Danini Supik, and Jose A. Cardenas) correlates student…

  5. Focused ion beam micromilling and articles therefrom

    DOEpatents

    Lamartine, B.C.; Stutz, R.A.

    1998-06-30

    An ultrahigh vacuum focused ion beam micromilling apparatus and process are disclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters. 6 figs.

  6. Revitalize Electrical Program with Renewable Energy Focus

    ERIC Educational Resources Information Center

    Karns, Robert J.

    2012-01-01

    Starting a renewable energy technology (RET) program can be as simple as shifting the teaching and learning focus of a traditional electricity program toward energy production and energy control systems. Redirecting curriculum content and delivery to address photovoltaic solar (PV solar) technology and small wind generation systems is a natural…

  7. Properties of Electromagnetic Field Focusing Probe

    Microsoft Academic Search

    William S. Yamanashi; Nabil A. Yassa; Deborah L. Hill; Angelo A. Patil; Patrick D. Lester

    1988-01-01

    The electromagnetic field focusing (EFF) apparatus consists of a radio fre quency generator, solenoidal coil, and a hand-held or catheter probe. Applica tions such as aneurysm treatment, angioplasty, and neurosurgery in various models have been reported. The probe is operated in the near field (within one wavelength of an electromagnetic field source) of a coil inducing eddy currents in biological

  8. Optimal design of focused experiments and surveys

    NASA Astrophysics Data System (ADS)

    Curtis, Andrew

    1999-10-01

    Experiments and surveys are often performed to obtain data that constrain some previously underconstrained model. Often, constraints are most desired in a particular subspace of model space. Experiment design optimization requires that the quality of any particular design can be both quantified and then maximized. This study shows how the quality can be defined such that it depends on the amount of information that is focused in the particular subspace of interest. In addition, algorithms are presented which allow one particular focused quality measure (from the class of focused measures) to be evaluated efficiently. A subclass of focused quality measures is also related to the standard variance and resolution measures from linearized inverse theory. The theory presented here requires that the relationship between model parameters and data can be linearized around a reference model without significant loss of information. Physical and financial constraints define the space of possible experiment designs. Cross-well tomographic examples are presented, plus a strategy for survey design to maximize information about linear combinations of parameters such as bulk modulus, ? =?+ 2?/3.

  9. Our Focus is on YOUR Future

    E-print Network

    Eustice, Ryan

    Cybernet Systems Corp. Ford Motor Company General Dynamics General Electric (Aviation Systems, Energy, personal computers, automotive electronics, and bioelectrical devices are all the work of electricalOur Focus is on YOUR Future The Electrical Engineering program at Michigan is one of the highest

  10. Focused ion beam manufacturing of magnetic nanostructures

    Microsoft Academic Search

    Andrey Lavrenov

    2007-01-01

    A number of patterning methods including conventional photo-lithography and E-beam lithography have been employed to pattern devices with critical dimensions of submicrometer levels. The methods of device fabrication by lithography and multilevel processing are usually specific to the chemical and physical properties of the etchants and materials used, and require a number of processing steps. As an alternative, focused ion

  11. Beam hysteresis via reorientational self-focusing.

    PubMed

    Alberucci, Alessandro; Piccardi, Armando; Kravets, Nina; Assanto, Gaetano

    2014-10-15

    We theoretically investigate light self-trapping in nonlinear dielectrics with a reorientational response subject to threshold, specifically nematic liquid crystals. Beyond a finite excitation, two solitary waves exist for any given power, with an hysteretic dynamics due to feedback between beam size, self-focusing and the nonlinear threshold. Soliton stability is discussed on the basis of the system free energy. PMID:25361096

  12. Focus on Form in Live Chats

    ERIC Educational Resources Information Center

    Chen, Wen-Chun; Eslami, Zohreh

    2013-01-01

    This study investigated the effectiveness of incidental focus on form in promoting second language development in text-based live chats. Sixteen college-level Taiwanese English language learners were partnered with American college students to complete two communicative tasks via synchronous chats on Instant Messenger. Language-related episodes…

  13. Math and Science Education. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1996

    1996-01-01

    This newsletter focuses on efforts to make math and science more attractive, relevant, and accessible to students, especially limited-English-proficient, minority, economically disadvantaged, female, and at-risk students. "TAAS Math Performance" (Linda Cantu) outlines recent statewide results for the controversial Texas Assessment of Academic…

  14. Focus. Volume 26, Number 2, Fall 2009

    ERIC Educational Resources Information Center

    Caspar, Emma, Ed.

    2009-01-01

    The purpose of "Focus" is to provide coverage of poverty-related research, events, and issues, and to acquaint a large audience with the work of the Institute for Research on Poverty by means of short essays on selected pieces of research. This issue contains the following articles: (1) Changing poverty and changing antipoverty policies (Maria…

  15. FOCUS on Promising Practices. Final Report.

    ERIC Educational Resources Information Center

    Royce, Sherry

    A newsletter titled "Focus" was published to disseminate significant current or previous Section 353 special demonstration projects in Pennsylvania. The project involved a review of previous exemplary projects, validation of 49 significant projects, and dissemination of them. Twenty special projects from Pennsylvania and the nation were selected…

  16. International Focus: Highlighting APPA Members Worldwide

    ERIC Educational Resources Information Center

    Glazner, Steve, Comp.

    2011-01-01

    While most APPA member institutions are located in the United States and Canada, there are also 45 of member institutions located internationally--from Australia and New Zealand to Southeast Asia to the Middle East to Europe. This article focuses on four of its international members: (1) American University of Kuwait (AUK); (2) American University…

  17. Focus Issue: Getting Excited About Glia

    NSDL National Science Digital Library

    Elizabeth M. Adler (American Association for the Advancement of Science; Science Signaling REV)

    2010-11-09

    This Focus Issue of Science Signaling complements the Science Special Issue and highlights glial cell function, development, and disease. This issue draws attention to the molecular mechanisms of drug resistance of a cancer of glial origin, and to signaling between glia and neurons. Although glia may not be excitable, they are clearly an exciting group of cells.

  18. Project-Based Learning. Focus On

    ERIC Educational Resources Information Center

    Clarke, Suzanne

    2009-01-01

    Project-Based Learning (PBL) connects standards-based content to real-world scenarios through the use of projects to improve student achievement. By engaging students in authentic problems that do not have a predetermined solution, students learn both subject matter and critical 21st-century skills. This "Focus On" addresses what separates PBL…

  19. Reading Motivation: A Focus on English Learners

    ERIC Educational Resources Information Center

    Protacio, Maria Selena

    2012-01-01

    Because of the numerous challenges that ELs face, such as having to concurrently learn the curriculum and the English language, it is critical to focus on motivation. However, little attention has been given to ELs' motivation to read in English. Based on an interview study, results indicate that ELs may be motivated to read in English to learn…

  20. Task-focused Summarization of Email

    Microsoft Academic Search

    Simon Corston-Oliver; Eric Ringger; Michael Gamon; Richard Campbell

    2004-01-01

    We describe SmartMail, a prototype system for automatically identifying action items (tasks) in email messages. SmartMail presents the user with a task-focused summary of a message. The summary consists of a list of action items extracted from the message. The user can add these action items to their \\

  1. 1 Focus on Energy 3 Dean's Corner

    E-print Network

    Crawford, T. Daniel

    is forecast to be more than 25% higher than the annual demand in 2008 when oil prices reached $150 per barrel for the electrical utilities sector. Together, these two sectors account for more than 80% of US primary energy useINSIDE 1 Focus on Energy 3 Dean's Corner 4 Director's Corner 5 Facilities Update 6 Biomass to Fuels

  2. Focus Issue: Coping with Cellular Stress

    NSDL National Science Digital Library

    Wei Wong (American Association for the Advancement of Science; Science Signaling REV)

    2009-11-10

    Organisms constantly face potential damage from internal and external sources, thus necessitating signaling cascades that couple specific cellular stresses to the appropriate responses. This Focus Issue of Science Signaling highlights the signaling pathways that are activated by and that mediate responses to diverse types of stresses.

  3. Practitioner-Focused Degrees in Politics

    ERIC Educational Resources Information Center

    Craig, John

    2010-01-01

    This article aims to explore practitioner-focused degrees in politics. It begins by defining the term and outlining the key features in comparison to other politics degrees. The underlying pedagogical principles that inform the design of teaching, learning, and assessment are then explored, before the article moves on to discuss the development of…

  4. Focusing Surface Plasmons with a Plasmonic Lens

    Microsoft Academic Search

    Zhaowei Liu; Jennifer M. Steele; Werayut Srituravanich; Yuri Pikus; Cheng Sun; Xiang Zhang

    2005-01-01

    We report the focusing of surface plasmon polaritons by circular and elliptical structures milled into optically thick metallic films or plasmonic lenses. Both theoretical and experimental data for the electromagnetic nearfield is presented. The nearfield is mapped experimentally using nearfield scanning optical microscopy and plasmonic lithography. We find that the intensity at the focal points of the plasmonic lenses increases

  5. Focused ion beam micromilling and articles therefrom

    DOEpatents

    Lamartine, Bruce C. (Los Alamos, NM); Stutz, Roger A. (Los Alamos, NM)

    1998-01-01

    An ultrahigh vacuum focused ion beam micromilling apparatus and process are isclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters.

  6. Interoceptive Focus Shapes the Experience of Time

    PubMed Central

    Pollatos, Olga; Laubrock, Jochen; Wittmann, Marc

    2014-01-01

    The perception of time is a fundamental part of human experience. Recent research suggests that the experience of time emerges from emotional and interoceptive (bodily) states as processed in the insular cortex. Whether there is an interaction between the conscious awareness of interoceptive states and time distortions induced by emotions has rarely been investigated so far. We aimed to address this question by the use of a retrospective time estimation task comparing two groups of participants. One group had a focus on interoceptive states and one had a focus on exteroceptive information while watching film clips depicting fear, amusement and neutral content. Main results were that attention to interoceptive processes significantly affected subjective time experience. Fear was accompanied with subjective time dilation that was more pronounced in the group with interoceptive focus, while amusement led to a quicker passage of time which was also increased by interoceptive focus. We conclude that retrospective temporal distortions are directly influenced by attention to bodily responses. These effects might crucially interact with arousal levels. Sympathetic nervous system activation affecting memory build-up might be the decisive factor influencing retrospective time judgments. Our data substantially extend former research findings underscoring the relevance of interoception for the effects of emotional states on subjective time experience. PMID:24489807

  7. Focus of Attention and Putting Performance.

    ERIC Educational Resources Information Center

    Boutcher, Stephen H.; Crews, Debra J.

    The effect of a preshot attentional/behavioral routine on putting performance was investigated. Subjects were randomly assigned to four groups: (1) Male Routine (MR); (2) Female Routine (FR); (3) Male Control (MC); and (4) Female Control (FC). Subjects in the FR and MR groups were given individualized putting routines which focused on specific…

  8. Gifted and Talented Students. IDRA Focus.

    ERIC Educational Resources Information Center

    IDRA Newsletter, 1998

    1998-01-01

    This theme issue includes five articles that focus on issues surrounding gifted and talented students, especially as they relate to poor, minority, or limited-English-proficient children. "Traditional Methods of Identifying Gifted Students Overlooks Many" (Linda Cantu) presents findings from the National Educational Longitudinal Study that…

  9. Quality? Is it Allowed? FACTC Focus, 2006

    ERIC Educational Resources Information Center

    Doerr, Mark, Ed.

    2006-01-01

    "FACTC Focus" is a publication of Faculty Association of Community and Technical Colleges (FACTC) with the purpose of presenting diverse views on faculty issues. Included in this issue are: (1) Shooting In The Dark: Evaluating Distance Learning Instruction (Stephanie Delaney); (2) Trust Who? - Trust and Learning: Crafting a Conversation That…

  10. Presentational Focus in Heritage and Monolingual Spanish

    ERIC Educational Resources Information Center

    Hoot, Bradley

    2012-01-01

    In Spanish, it is most commonly claimed that constituents in narrow presentational focus appear rightmost, where they also get main stress (1a), while stress in situ (1b) is infelicitous. (1) [Context: Who bought a car?]. a. Compró un carro mi [mamá][subscript F]. bought a car my mom. b. Mi [mamá ][subscript F] compró un carro. However, some…

  11. SAR data focusing using seismic migration techniques

    Microsoft Academic Search

    Ciro Cafforio; Claudio Prati; Fabio Rocca

    1991-01-01

    The focusing of synthetic-aperture-radar (SAR) data using migration techniques quite similar to those used in geophysics is treated. The algorithm presented works in the ?-kx domain. Because time delays can be easily accommodated with phase shifts that increase linearly with ?, range migration poses no problem. The algorithm is described in plane geometry first, where range migration and phase history

  12. Focusing of synchrotron radiation with polycapillary optics

    Microsoft Academic Search

    F. A. Hofmann; C. A. Freinberg-Trufas; S. M. Owens; S. D. Padiyar; C. A. MacDonald

    1997-01-01

    Polycapillary optics are arrays of thousands of hollow capillary tubes. Focal spots are produced from the overlap of outputs from multiple channels at distances of 10–100 mm from the output of the optic. Synchrotron focusing was performed with two polycapillary X-ray optics. The spot size for the monolithic optic was 80 ?m, which yielded a measured gain in photon flux

  13. Focusing of synchrotron radiation with polycapillary optics

    Microsoft Academic Search

    F. A. Hofmann; C. A. Freinberg-Trufas; S. M. Owens; S. D. Padiyar; C. A. MacDonald

    1997-01-01

    Polycapillary optics are arrays of thousands of hollow capillary tubes. Focal spots are produced from the overlap of outputs from multiple channels at distances of 10-100 mm from the output of the optic. Synchrotron focusing was performed with two polycapillary X-ray optics. The spot size for the monolithic optic was 80 mum, which yielded a measured gain in photon flux

  14. Time Reversal Focusing Applied to Lithotripsy

    Microsoft Academic Search

    Jean-Louis Thomas; François Wu; Mathias Fink

    1996-01-01

    Time reversal of ultrasonic field allows a very efficient approach to focusing pulsed ultrasonic waves through lossless inhomogeneous media. Time reversal mirrors (TRM) are made of large transducer arrays, allowing the incident acoustic field to be sampled, time reversed and re-emitted. Time reversal processing permits a choice of any temporal window to be time reversed, allowing operation in an iterative

  15. Charm Hadronic Decays from Focus: Lessons Learnt

    NASA Astrophysics Data System (ADS)

    Bianco, Stefano; Pedrini, Daniele; Reis, Alberto

    The FOCUS photoproduction experiment took data in the ninenties and produced a wealth of results in charm physics. Some of the studies were seminal for contemporary experiments, and even paved the way for the technology of many charm and beauty analysis tools.

  16. Focusing and shadowing of ELF signals

    Microsoft Academic Search

    E. C. Field; C. R. Warber; R. G. Joiner

    1986-01-01

    Phase velocity transitions in the earth-ionosphere waveguide can focus or shadow ELF signals and give rise to anomalies less than a megameter in extent. This paper develops a hybrid method to calculate those effects: it uses full-wave theory to determine local TEM mode parameters, but traces rays to describe the signal's lateral structure. The method is applied to models of

  17. |Research Focus Tits, noise and urban bioacoustics

    E-print Network

    Katti, Madhusudan

    |Research Focus Tits, noise and urban bioacoustics Madhusudan Katti and Paige S. Warren Center respond to elevated background noise by altering their songs. They found that urban great tits Parus major recorded the songs of male great tits and the background noise in their territories whilst they were

  18. Expanding the Focus of Career Assessment.

    ERIC Educational Resources Information Center

    Lock, Jared D.; Hogan, Robert

    2000-01-01

    Issues affecting career assessment include change in the focus and definition of career, emphasis on quality of work life, expansion of career paths, increased amount of career information available on the Internet, and questionable quality of online assessment. An expanded model of career assessment now includes technical fit, personal fit,…

  19. Focused Recharge in a Theoretical Raingarden

    Microsoft Academic Search

    A. R. Dussaillant; K. W. Potter; C. Wu

    2001-01-01

    Traditional stormwater management, which relies heavily on detention, does not mitigate groundwater depletion resulting from groundwater pumping and loss of groundwater recharge. In recent years there has been increasing interest in the use of practices, such as raingardens, that encourage infiltration of stormwater as a means of mitigating groundwater impacts. These can be particularly effective when infiltration is focused in

  20. Observation of Cumulative Spatial Focusing of Atoms

    Microsoft Academic Search

    Windell H. Oskay; Daniel A. Steck; Mark G. Raizen

    2002-01-01

    We report an experimental study of the spatial distribution of ultracold cesium atoms exposed to a series of kicks from a standing wave of light. We observe cumulative focusing, leading to a spatial array of atoms which is of interest for atomic lithography. To observe the spatial distribution, we developed a free-space measurement technique that enables the reconstruction of the

  1. The changing focus of marine mammal conservation

    Microsoft Academic Search

    Robert J. Hofman

    1995-01-01

    Overexploitation has been the principal focus of marine mammal conservation. Less attention has been paid to bycatch in commercial fisheries; entanglement in lost and discarded fishing gear; food shortages owing to climate change and\\/or overharvesting of essential prey; point and non-point source pollution; and diseases. Also, relatively little attention has been paid to situations where marine mammals pose threats to

  2. Has the AAMC Lost Its Focus?

    ERIC Educational Resources Information Center

    Robinson, John A.

    2002-01-01

    It seems that the Association of American Medical Colleges has bought, at least partly, into the fads that undermine education at lower levels. This is a problem for Dr. Robinson, who writes that the training needed to focus a multitude of modern technological resources on the diagnosis and treatment of individual patients is an intense process…

  3. With national attention focused on the massive

    E-print Network

    With national attention focused on the massive oil spill in the Gulf of Mexico, the Applied Science spill response by Stennis and its resident agencies. ASTPO manages the agency's Gulf of Mexico and barrier islands, or environmental parameters, such as water quality. So far, the projects study sites have

  4. Focus Article Beetle horns and horned beetles

    E-print Network

    Moczek, Armin P.

    within the Scarabaeidae, the Dynastinae (rhinoceros beetles) and Scarabaeinae (true dung beetles).1Focus Article Beetle horns and horned beetles: emerging models in developmental evolution of horned beetles and beetle horns as study systems amenable to the integration of a wide range

  5. Focus on Seat Belt Use in China

    Microsoft Academic Search

    Virginia Routley; Joan Ozanne-Smith; Min Yu; Jianyue Wang; Ming Wu; Junhe Zhang; Yu Qin; Ming Zhao

    2010-01-01

    Objective: To explain low seat belt use prevalence results of observation and interview surveys in Nanjing, Jiangsu Province, and Zhoushan, Zhejiang Province, and to extend knowledge on associated seat belt use determinants.Method: Ten focus groups comprising professional, owner, and taxi drivers; passengers; van drivers (Nanjing); or police (Zhoushan) were conducted to capture a range of experiences, attitudes, and opinions.Results: There

  6. Radiation Reaction in a Continuous Focusing Channel

    Microsoft Academic Search

    Zhirong Huang; Pisin Chen; Ronald D. Ruth

    1995-01-01

    We show that the radiation damping rate of the transverse action of a particle in a straight, continuous focusing system is independent of the particle energy, and that no quantum excitation is induced. This absolute damping effect leads to the existence of a transverse ground state to which the particle inevitably decays and yields the minimum beam emittance that one

  7. FOCUS: MALDI Exploring Infrared Wavelength Matrix-

    E-print Network

    Chait, Brian T.

    FOCUS: MALDI Exploring Infrared Wavelength Matrix- Assisted Laser Desorption/Ionization of Proteins) to infrared-wavelength matrix-assisted time-of-flight mass spectrometry (IR-MALDI-TOF-MS) of proteins. The shapes of the spectral peaks obtained with DE-IR-MALDI-MS are compared with those obtained from the same

  8. Course Focus HORT 225: Landscape Graphics I

    E-print Network

    Dyer, Bill

    in this course's syllabus are "Be fearless." This course is the introductory course to the Landscape Design major that the landscape design field encompasses and the design process that landscape designers utilize. The majority a landscape designer. HORT 225 Landscape Graphics I focuses on hand graphics, while HORT 226 Landscape

  9. Ballistic dispersion in temperature gradient focusing

    E-print Network

    Santiago, Juan G.

    Ballistic dispersion in temperature gradient focusing BY DAVID E. HUBER* AND JUAN G. SANTIAGO kinematic (or ballistic) dispersion. In most microfluidic systems, this dispersion regime is transient­Aris; ballistic; electroosmotic flow 1. Introduction Dispersion, the natural tendency for ordered molecules

  10. Focused Local Search for Random 3Satisfiability

    Microsoft Academic Search

    Sakari Seitz; Mikko Alava; Pekka Orponen

    2005-01-01

    A local search algorithm solving an NP-complete optimisation problem can be viewed as a stochastic process moving in an 'energy landscape' towards eventually finding an optimal solution. For the random 3-satisfiability problem, the heuristic of focusing the local moves on the presently unsatisfied clauses is known to be very effective: the time to solution has been observed to grow only

  11. Focused RF hyperthermia using magnetic fluids

    PubMed Central

    Tasci, T. Onur; Vargel, Ibrahim; Arat, Anil; Guzel, Elif; Korkusuz, Petek; Atalar, Ergin

    2009-01-01

    Heat therapies such as hyperthermia and thermoablation are very promising approaches in the treatment of cancer. Compared with available hyperthermia modalities, magnetic fluid hyperthermia (MFH) yields better results in uniform heating of the deeply situated tumors. In this approach, fluid consisting of superparamagnetic particles (magnetic fluid) is delivered to the tumor. An alternating (ac) magnetic field is then used to heat the particles and the corresponding tumor, thereby ablating it. However, one of the most serious shortcomings of this technique is the unwanted heating of the healthy tissues. This results from the magnetic fluid diffusion from the tumor to the surrounding tissues or from incorrect localization of the fluids in the target tumor area. In this study, the authors demonstrated that by depositing appropriate static (dc) magnetic field gradients on the alternating (ac) magnetic fields, focused heating of the magnetic particles can be achieved. A focused hyperthermia system was implemented by using two types of coils: dc and ac coils. The ac coil generated the alternating magnetic field responsible for the heating of the magnetic particles; the dc coil was used to superimpose a static magnetic field gradient on the alternating magnetic field. In this way, focused heating of the particles was obtained in the regions where the static field was dominated by the alternating magnetic field. In vitro experiments showed that as the magnitude of the dc solenoid currents was increased from 0 to 1.8 A, the specific absorption rate (SAR) of the superparamagnetic particles 2 cm apart from the ac solenoid center decreased by a factor of 4.5, while the SAR of the particles at the center was unchanged. This demonstrates that the hyperthermia system is capable of precisely focusing the heat at the center. Additionally, with this approach, shifting of the heat focus can be achieved by applying different amounts of currents to individual dc solenoids. In vivo experiments were performed with adult rats, where magnetic fluids were injected percutaneously into the tails (with homogeneous fluid distribution inside the tails). Histological examination showed that, as we increased the dc solenoid current from 0.5 to 1.8 A, the total burned volume decreased from 1.6 to 0.2 cm3 verifying the focusing capability of the system. The authors believe that the studies conducted in this work show that MFH can be a much more effective method with better heat localization and focusing abilities. PMID:19544810

  12. Feasibility of noninvasive cavitation-guided blood-brain barrier opening using focused ultrasound and microbubbles in nonhuman

    E-print Network

    Konofagou, Elisa E.

    Feasibility of noninvasive cavitation-guided blood-brain barrier opening using focused ultrasound://apl.aip.org/about/rights_and_permissions #12;Feasibility of noninvasive cavitation-guided blood-brain barrier opening using focused ultrasound 2011; published online 20 April 2011 In vivo transcranial and noninvasive cavitation detection

  13. Model-based simulation of focused beam fields produced by a phased array ultrasonic transducer in dissimilar metal welds

    Microsoft Academic Search

    Jing Ye; Hak-Joon Kim; Sung-Jin Song; Sung-Sik Kang; Kyungcho Kim; Myung-Ho Song

    2011-01-01

    Phased array ultrasound testing (PAUT) can produce steerable and tightly focused ultrasonic beams, so it is widely used for detecting flaws. However, inspection of dissimilar metal welds (DMWs) using phased array ultrasound is not easy at all, since ultrasonic beams are skewed and distorted severely in the welds that are anisotropic and inhomogeneous elastic media. So, to increase focusing efficiency

  14. Non?traditional explosives: Potential detection problems

    Microsoft Academic Search

    Jimmie C. Oxley

    1993-01-01

    Most explosive detection technologies have been focused on nitro?based military explosives because, indeed, they have figured in international terrorist incidents Not only are they readily available through purchase or theft or from sponsoring states, but methods for home synthesis of TNT, PETN and RDX are widely available. Presently substantial resources are being committed to developing explosive detection technologies to protect

  15. MACHINE LEARNING SYSTEMS FOR DETECTING DRIVER DROWSINESS

    Microsoft Academic Search

    Esra Vural; Müjdat Çetin; Aytül Erçil

    The advance of computing technology has provided the means for building intelligent vehicle systems. Drowsy driver detection system is one of the potential applications of intelligent vehicle systems. Previous approaches to drowsiness detection primarily make pre-assumptions about the relevant behavior, focusing on blink rate, eye closure, and yawning. Here we employ machine learning to data-mine actual human behavior during drowsiness

  16. Quantum dots in molecular detection of disease

    Microsoft Academic Search

    V. J. Bailey; C. M. Puleo; Y. P. Ho; H. C. Yeh; T. H. Wang

    2009-01-01

    The unique photophysical properties of semiconductor quantum dots (QDs) have made them ideal for use as spectral labels and luminescent probes. In this review, applications are presented in which QDs function as active participants in nanoscale biosensor assemblies, where replacing traditional molecular fluorophores results in improved assay performance. Specific focus is on disease detection with applications including multiplexed target detection,

  17. Fast Fight Detection

    PubMed Central

    Serrano Gracia, Ismael; Deniz Suarez, Oscar; Bueno Garcia, Gloria; Kim, Tae-Kyun

    2015-01-01

    Action recognition has become a hot topic within computer vision. However, the action recognition community has focused mainly on relatively simple actions like clapping, walking, jogging, etc. The detection of specific events with direct practical use such as fights or in general aggressive behavior has been comparatively less studied. Such capability may be extremely useful in some video surveillance scenarios like prisons, psychiatric centers or even embedded in camera phones. As a consequence, there is growing interest in developing violence detection algorithms. Recent work considered the well-known Bag-of-Words framework for the specific problem of fight detection. Under this framework, spatio-temporal features are extracted from the video sequences and used for classification. Despite encouraging results in which high accuracy rates were achieved, the computational cost of extracting such features is prohibitive for practical applications. This work proposes a novel method to detect violence sequences. Features extracted from motion blobs are used to discriminate fight and non-fight sequences. Although the method is outperformed in accuracy by state of the art, it has a significantly faster computation time thus making it amenable for real-time applications. PMID:25860667

  18. Automatic EEG spike detection.

    PubMed

    Harner, Richard

    2009-10-01

    Since the 1970s advances in science and technology during each succeeding decade have renewed the expectation of efficient, reliable automatic epileptiform spike detection (AESD). But even when reinforced with better, faster tools, clinically reliable unsupervised spike detection remains beyond our reach. Expert-selected spike parameters were the first and still most widely used for AESD. Thresholds for amplitude, duration, sharpness, rise-time, fall-time, after-coming slow waves, background frequency, and more have been used. It is still unclear which of these wave parameters are essential, beyond peak-peak amplitude and duration. Wavelet parameters are very appropriate to AESD but need to be combined with other parameters to achieve desired levels of spike detection efficiency. Artificial Neural Network (ANN) and expert-system methods may have reached peak efficiency. Support Vector Machine (SVM) technology focuses on outliers rather than centroids of spike and nonspike data clusters and should improve AESD efficiency. An exemplary spike/nonspike database is suggested as a tool for assessing parameters and methods for AESD and is available in CSV or Matlab formats from the author at brainvue@gmail.com. Exploratory Data Analysis (EDA) is presented as a graphic method for finding better spike parameters and for the step-wise evaluation of the spike detection process. PMID:19780347

  19. Fast fight detection.

    PubMed

    Serrano Gracia, Ismael; Deniz Suarez, Oscar; Bueno Garcia, Gloria; Kim, Tae-Kyun

    2015-01-01

    Action recognition has become a hot topic within computer vision. However, the action recognition community has focused mainly on relatively simple actions like clapping, walking, jogging, etc. The detection of specific events with direct practical use such as fights or in general aggressive behavior has been comparatively less studied. Such capability may be extremely useful in some video surveillance scenarios like prisons, psychiatric centers or even embedded in camera phones. As a consequence, there is growing interest in developing violence detection algorithms. Recent work considered the well-known Bag-of-Words framework for the specific problem of fight detection. Under this framework, spatio-temporal features are extracted from the video sequences and used for classification. Despite encouraging results in which high accuracy rates were achieved, the computational cost of extracting such features is prohibitive for practical applications. This work proposes a novel method to detect violence sequences. Features extracted from motion blobs are used to discriminate fight and non-fight sequences. Although the method is outperformed in accuracy by state of the art, it has a significantly faster computation time thus making it amenable for real-time applications. PMID:25860667

  20. Multisource oil spill detection

    NASA Astrophysics Data System (ADS)

    Salberg, Arnt B.; Larsen, Siri O.; Zortea, Maciel

    2013-10-01

    In this paper we discuss how multisource data (wind, ocean-current, optical, bathymetric, automatic identification systems (AIS)) may be used to improve oil spill detection in SAR images, with emphasis on the use of automatic oil spill detection algorithms. We focus particularly on AIS, optical, and bathymetric data. For the AIS data we propose an algorithm for integrating AIS ship tracks into automatic oil spill detection in order to improve the confidence estimate of a potential oil spill. We demonstrate the use of ancillary data on a set of SAR images. Regarding the use of optical data, we did not observe a clear correspondence between high chlorophyll values (estimated from products derived from optical data) and observed slicks in the SAR image. Bathymetric data was shown to be a good data source for removing false detections caused by e.g. sand banks on low tide. For the AIS data we observed that a polluter could be identified for some dark slicks, however, a precise oil drift model is needed in order to identify the polluter with high certainty.

  1. Numerical study of thermoviscous effects in ultrasound-induced acoustic streaming in microchannels

    NASA Astrophysics Data System (ADS)

    Muller, Peter Barkholt; Bruus, Henrik

    2014-10-01

    We present a numerical study of thermoviscous effects on the acoustic streaming flow generated by an ultrasound standing-wave resonance in a long straight microfluidic channel containing a Newtonian fluid. These effects enter primarily through the temperature and density dependence of the fluid viscosity. The resulting magnitude of the streaming flow is calculated and characterized numerically, and we find that even for thin acoustic boundary layers, the channel height affects the magnitude of the streaming flow. For the special case of a sufficiently large channel height, we have successfully validated our numerics with analytical results from 2011 by Rednikov and Sadhal for a single planar wall. We analyzed the time-averaged energy transport in the system and the time-averaged second-order temperature perturbation of the fluid. Finally, we have made three main changes in our previously published numerical scheme to improve the numerical performance: (i) The time-averaged products of first-order variables in the time-averaged second-order equations have been recast as flux densities instead of as body forces. (ii) The order of the finite-element basis functions has been increased in an optimal manner. (iii) Based on the International Association for the Properties of Water and Steam (IAPWS 1995, 2008, and 2011), we provide accurate polynomial fits in temperature for all relevant thermodynamic and transport parameters of water in the temperature range from 10 to 50 ?C.

  2. A fast and switchable microfluidic mixer based on ultrasound-induced vaporization of perfluorocarbon.

    PubMed

    Bezagu, Marine; Arseniyadis, Stellios; Cossy, Janine; Couture, Olivier; Tanter, Mickael; Monti, Fabrice; Tabeling, Patrick

    2015-04-21

    Mixing two fluids together within a microfluidic device still remains a challenging operation today. In order to achieve this goal, a number of effective micromixers have been developed over the years based on the use of either passive or active systems. Typically, passive mixers require no external energy, are more robust, and are easy to manufacture albeit they are poorly flexible. Active mixers, on the other hand, rely on external disturbance and are thus more difficult to use but are proven to have greater efficacy. Here, we report a particularly effective, remotely induced and switchable microfluidic mixer, which relies on the concomitant use of ultrasound and a perfluorocarbon (PFC) phase, with the latter benefiting from its immiscibility with most fluids and its low boiling point. More specifically, our approach is based on localized vaporization of a PFC phase at the focal zone of a transducer leading to efficient mixing of two adjacent fluids. The results show that mixing occurs ~100 ms following the delivery of the acoustic pulse, while a laminar flow is re-established on roughly the same time scale. Overall, this method is simple and effective, does not require tailored channel geometries, is compatible with both hydrophilic and hydrophobic microfluidic systems, and is applicable to a wide range of Reynolds numbers (10(-4) < Re < 2.10(0)), and the PFC phase can be easily separated from the mixed phase at the end of the run. PMID:25778877

  3. Numerical study of thermoviscous effects in ultrasound-induced acoustic streaming in microchannels.

    PubMed

    Muller, Peter Barkholt; Bruus, Henrik

    2014-10-01

    We present a numerical study of thermoviscous effects on the acoustic streaming flow generated by an ultrasound standing-wave resonance in a long straight microfluidic channel containing a Newtonian fluid. These effects enter primarily through the temperature and density dependence of the fluid viscosity. The resulting magnitude of the streaming flow is calculated and characterized numerically, and we find that even for thin acoustic boundary layers, the channel height affects the magnitude of the streaming flow. For the special case of a sufficiently large channel height, we have successfully validated our numerics with analytical results from 2011 by Rednikov and Sadhal for a single planar wall. We analyzed the time-averaged energy transport in the system and the time-averaged second-order temperature perturbation of the fluid. Finally, we have made three main changes in our previously published numerical scheme to improve the numerical performance: (i) The time-averaged products of first-order variables in the time-averaged second-order equations have been recast as flux densities instead of as body forces. (ii) The order of the finite-element basis functions has been increased in an optimal manner. (iii) Based on the International Association for the Properties of Water and Steam (IAPWS 1995, 2008, and 2011), we provide accurate polynomial fits in temperature for all relevant thermodynamic and transport parameters of water in the temperature range from 10 to 50 °C. PMID:25375602

  4. Ultrasound-induced modulation of cardiac rhythm in neonatal rat ventricular cardiomyocytes.

    PubMed

    Fleischman, Andrew; Vecchio, Christopher; Sunny, Youhan; Bawiec, Christopher R; Lewin, Peter A; Kresh, J Yasha; Kohut, Andrew R

    2015-06-01

    Isolated neonatal rat ventricular cardiomyocytes were used to study the influence of ultrasound on the chronotropic response in a tissue culture model. The beat frequency of the cells, varying from 40 to 90 beats/min, was measured based upon the translocation of the nuclear membrane captured by a high-speed camera. Ultrasound pulses (frequency = 2.5 MHz) were delivered at 300-ms intervals [3.33 Hz pulse repetition frequency (PRF)], in turn corresponding to 200 pulses/min. The intensity of acoustic energy and pulse duration were made variable, 0.02-0.87 W/cm(2) and 1-5 ms, respectively. In 57 of 99 trials, there was a noted average increase in beat frequency of 25% with 8-s exposures to ultrasonic pulses. Applied ultrasound energy with a spatial peak time average acoustic intensity (Ispta) of 0.02 W/cm(2) and pulse duration of 1 ms effectively increased the contraction rate of cardiomyocytes (P < 0.05). Of the acoustic power tested, the lowest level of acoustic intensity and shortest pulse duration proved most effective at increasing the electrophysiological responsiveness and beat frequency of cardiomyocytes. Determining the optimal conditions for delivery of ultrasound will be essential to developing new models for understanding mechanoelectrical coupling (MEC) and understanding novel nonelectrical pacing modalities for clinical applications. PMID:25858493

  5. Influence of Lipid Shell Physicochemical Properties on Ultrasound-Induced Microbubble Destruction

    PubMed Central

    Borden, Mark A.; Kruse, Dustin E.; Caskey, Charles F.; Zhao, Shukui; Dayton, Paul A.; Ferrara, Katherine W.

    2006-01-01

    We present the first study of the effects of monolayer shell physicochemical properties on the destruction of lipid-coated microbubbles during insonification with single, one-cycle pulses at 2.25 MHz and low-duty cycles. Shell cohesiveness was changed by varying phospholipid and emulsifier composition, and shell microstructure was controlled by postproduction processing. Individual microbubbles with initial resting diameters between 1 and 10 ?m were isolated and recorded during pulsing with bright-field and fluorescence video microscopy. Microbubble destruction occurred through two modes: acoustic dissolution at 400 and 600 kPa and fragmentation at 800 kPa peak negative pressure. Lipid composition significantly impacted the acoustic dissolution rate, fragmentation propensity, and mechanism of excess lipid shedding. Less cohesive shells resulted in micron-scale or smaller particles of excess lipid material that shed either spontaneously or on the next pulse. Conversely, more cohesive shells resulted in the buildup of shell-associated lipid strands and globular aggregates of several microns in size; the latter showed a significant increase in total shell surface area and lability. Lipid-coated microbubbles were observed to reach a stable size over many pulses at intermediate acoustic pressures. Observations of shell microstructure between pulses allowed interpretation of the state of the shell during oscillation. We briefly discuss the implications of these results for therapeutic and diagnostic applications involving lipid-coated microbubbles as ultrasound contrast agents and drug/gene delivery vehicles. PMID:16422411

  6. The focus group method: Insights from focus group interviews on sexual health with adolescents

    Microsoft Academic Search

    Abbey Hyde; Etaoine Howlett; Dympna Brady; Jonathan Drennan

    2005-01-01

    This article concerns the manner in which group interaction during focus groups impacted upon the data generated in a study of adolescent sexual health. Twenty-nine group interviews were conducted with secondary school pupils in Ireland, and data were subjected to a qualitative analysis. In exploring the relationship between method and theory generation, we begin by focusing on the ethnographic potential

  7. Selecting the Optimal Focus Measure for Autofocusing and DepthfromFocus

    E-print Network

    Subbarao, Murali "Rao"

    . The method is based on two new metrics that have been defined for estimating the noise­sensitivity to AUM. AUM and ARMS error metrics are based on a theoretical noise sensitivity analysis of focus and simulation experiments. For a given camera, the optimally accurate focus measure may change from one object

  8. Editorial Focus Fish Smell. Focus on "Odorant Specificity of Single Olfactory Bulb Neurons

    E-print Network

    Stephens, Jacqueline

    Editorial Focus Fish Smell. Focus on "Odorant Specificity of Single Olfactory Bulb Neurons to Amino bulb, or antennal lobe. The precise nature of these odor features is yet to be determined for the most of this type in the fish, precise subclasses of olfactory bulb neurons for coding biologically significant

  9. Focus Issue: Reactive Oxygen Species--Friend or Foe?

    NSDL National Science Digital Library

    Nancy R. Gough (DC; American Association for the Advancement of Science, Washington REV)

    2006-04-25

    Science’s STKE focuses on the signaling pathways activated in response to pathological accumulation of reactive oxygen species (ROS), as well as on mechanisms by which cells have harnessed these reactive molecules as active participants in signaling that leads to a desirable cellular response. ROS are chemically reactive because they contain unpaired electrons and, depending on the location of their production and the molecules with which they interact, they can cause cellular damage or trigger specific signaling events. Indeed, kinases and phosphatases are now recognized as key molecules that can be modified by interaction with ROS, and the Protocol by Wu and Terada describes a method for detecting oxidatively modified protein tyrosine phosphatases. In a Perspective, Michel et al. discuss how susceptibility to elevated ROS contributes to death of specific neurons and in a Review, Storz discusses the signaling pathways activated to detoxify ROS and how mitochondrial ROS may contribute to aging.

  10. Mixed waste characterization, treatment & disposal focus area

    SciTech Connect

    NONE

    1996-08-01

    The mission of the Mixed Waste Characterization, Treatment, and Disposal Focus Area (referred to as the Mixed Waste Focus Area or MWFA) is to provide treatment systems capable of treating DOE`s mixed waste in partnership with users, and with continual participation of stakeholders, tribal governments, and regulators. The MWFA deals with the problem of eliminating mixed waste from current and future storage in the DOE complex. Mixed waste is waste that contains both hazardous chemical components, subject to the requirements of the Resource Conservation and Recovery Act (RCRA), and radioactive components, subject to the requirements of the Atomic Energy Act. The radioactive components include transuranic (TRU) and low-level waste (LLW). TRU waste primarily comes from the reprocessing of spent fuel and the use of plutonium in the fabrication of nuclear weapons. LLW includes radioactive waste other than uranium mill tailings, TRU, and high-level waste, including spent fuel.

  11. Focused electron and ion beam systems

    DOEpatents

    Leung, Ka-Ngo; Reijonen, Jani; Persaud, Arun; Ji, Qing; Jiang, Ximan

    2004-07-27

    An electron beam system is based on a plasma generator in a plasma ion source with an accelerator column. The electrons are extracted from a plasma cathode in a plasma ion source, e.g. a multicusp plasma ion source. The beam can be scanned in both the x and y directions, and the system can be operated with multiple beamlets. A compact focused ion or electron beam system has a plasma ion source and an all-electrostatic beam acceleration and focusing column. The ion source is a small chamber with the plasma produced by radio-frequency (RF) induction discharge. The RF antenna is wound outside the chamber and connected to an RF supply. Ions or electrons can be extracted from the source. A multi-beam system has several sources of different species and an electron beam source.

  12. Radio frequency focused interdigital linear accelerator

    DOEpatents

    Swenson, Donald A.; Starling, W. Joel

    2006-08-29

    An interdigital (Wideroe) linear accelerator employing drift tubes, and associated support stems that couple to both the longitudinal and support stem electromagnetic fields of the linac, creating rf quadrupole fields along the axis of the linac to provide transverse focusing for the particle beam. Each drift tube comprises two separate electrodes operating at different electrical potentials as determined by cavity rf fields. Each electrode supports two fingers, pointing towards the opposite end of the drift tube, forming a four-finger geometry that produces an rf quadrupole field distribution along its axis. The fundamental periodicity of the structure is equal to one half of the particle wavelength .beta..lamda., where .beta. is the particle velocity in units of the velocity of light and .lamda. is the free space wavelength of the rf. Particles are accelerated in the gaps between drift tubes. The particle beam is focused in regions inside the drift tubes.

  13. Self-focusing of whistler waves

    NASA Technical Reports Server (NTRS)

    Karpman, V. I.; Kaufman, R. N.; Shagalov, A. G.

    1992-01-01

    The theory of axially symmetric self-focusing of whistler waves, based on the full system of Maxwell equations, is developed. The plasma is described by the magnetohydrodynamic equations including the ponderomotive force from RF field. The nonlinear Schrodinger equations (NSE) for arbitrary azimuthal modes of whistler waves are derived. It is shown that they differ from the NSE for a scalar field; this is connected with an intrinsic angular momentum due to the rotating polarization of whistlers. It is shown that the self-focusing, as described by the NSE, differs in its final stage from the results following the full set of Maxwell equations. The latter gives defocusing after sufficient narrowing of the initial wave beam, due to transformation of the trapped wave into a nontrapped branch which is not contained in the NSE description. The oscillatory character of the defocusing is demonstrated.

  14. Hormone purification by isoelectric focusing in space

    NASA Technical Reports Server (NTRS)

    Bier, M.

    1988-01-01

    The objective of the program was the definition and development of optimal methods for electrophoretic separations in microgravity. The approach is based on a triad consisting of ground based experiments, mathematical modeling and experiments in microgravity. Zone electrophoresis is a rate process, where separation is achieved in uniform buffers on the basis of differences in electrophoretic mobilities. Optimization and modeling of continuous flow electrophoresis mainly concern the hydrodynamics of the flow process, including gravity dependent fluid convection due to density gradients and gravity independent electroosmosis. Optimization of focusing requires a more complex model describing the molecular transport processes involved in electrophoresis of interacting systems. Three different focusing instruments were designed, embodying novel principles of fluid stabilization. Fluid stability was achieved by: (1) flow streamlining by means of membrane elements in combination with rapid fluid recycling; (2) apparatus rotation in combination with said membrane elements; and (3) shear stress induced by rapid recycling through a narrow gap channel.

  15. REPRODUCTIONEDITORIAL Focus on determinants of male fertility

    E-print Network

    Museo Nacional de Ciencias Naturales

    division, and fitness cost to the host. We conducted a series of experiments (both in vivo and in vitro cost on the host bacteria both in vitro (0.095 to 0.25) and in vivo (dairy calf model). Long). The blaCMY-2 genes have also been detected in E. coli and Salmonella isolates from ground meat (54). The

  16. Behavior profiling for robust anomaly detection

    Microsoft Academic Search

    Shun-Wen Hsiao; Yeali S. Sun; Meng Chang Chen; Hui Zhang

    2010-01-01

    Internet attacks are evolving using evasion techniques such as polymorphism and stealth scanning. Conventional detection systems using signature-based and\\/or rule-based anomaly detection techniques no longer suffice. It is difficult to predict what form the next malware attack will take and these pose a great challenge to the design of a robust intrusion detection system. We focus on the anomalous behavioral

  17. Consumer Evaluation of Dual Focus Mutual Aid

    Microsoft Academic Search

    Stephen Magura; Cherie L. Villano; Andrew Rosenblum; Howard S. Vogel; Thomas Betzler

    2008-01-01

    Double Trouble in Recovery (DTR) is a “dual focus,” 12 step-based mutual aid program tailored to assist recovery from co-occurring substance use and psychiatric disorders. Objective: To determine consumers' perceptions of DTR's usefulness for their recoveries and the relationships between perceived DTR usefulness and self-help processes, self-efficacy to cope with problems in recovery, and changes in behaviors conducive to dual

  18. Permanent magnet focused X-band photoinjector

    DOEpatents

    Yu, David U. L. (Rancho Palos Verdes, CA); Rosenzweig, James (Los Angeles, CA)

    2002-09-10

    A compact high energy photoelectron injector integrates the photocathode directly into a multicell linear accelerator with no drift space between the injection and the linac. High electron beam brightness is achieved by accelerating a tightly focused electron beam in an integrated, multi-cell, X-band rf linear accelerator (linac). The photoelectron linac employs a Plane-Wave-Transformer (PWT) design which provides strong cell-to-cell coupling, easing manufacturing tolerances and costs.

  19. Focused beam scatterometry for deep subwavelength metrology

    NASA Astrophysics Data System (ADS)

    Brown, Thomas G.; Alonso, Miguel A.; Vella, Anthony; Theisen, Michael J.; Head, Stephen T.; Gillmer, Steven R.; Ellis, Jonathan D.

    2014-03-01

    It is known that far-field scattered light requires a priori sample information in order to reconstruct nm-scale information such as is required in semiconductor metrology. We describe an approach to scatterometry that uses unconventional polarization states in the pupil of a high NA objective lens. We call this focused beam scatterometry; we will discuss the sensitivity limits to this approach and how it relates to micro-ellipsometry as well as low-NA scatterometry.

  20. Photoacoustic cell using elliptical acoustic focusing

    NASA Technical Reports Server (NTRS)

    Heritier, J.-M.; Fouquet, J. E.; Siegman, A. E.

    1982-01-01

    A photoacoustic cell has been developed in the form of an elliptical cylinder in which essentially all the acoustic energy generated by a laser beam passing down one axis is focused onto a cylindrical acoustic tranducer located along the other axis. Preliminary measurements on a liquid-filled cell of this design show high sensitivity and a notably clean impulse response. A similar design may be useful for photoacoustic measurements in vapors as well.

  1. Focus on thermoelectric effects in nanostructures

    NASA Astrophysics Data System (ADS)

    Sánchez, David; Linke, Heiner

    2014-11-01

    The field of nanoscale thermoelectrics began with a clear motivation for better performances of waste heat recovery processes by lowering the system dimensionality. Although this original inspiration still drives many recent developments, the field has also evolved to address fundamental questions on charge and energy transport across quantum conductors in the presence of both voltage and temperature differences. This ‘focus on’ collection provides new perspectives in the field and reports on the latest developments, both theoretically and experimentally.

  2. Focus Issue: Computational Approaches in Signal Transduction

    NSDL National Science Digital Library

    L. Bryan Ray (American Association for the Advancement of Science; Senior Editor of Science and Science's STKE REV)

    2004-02-10

    This STKE Focus Issue describes the STKE contribution to a coordinated effort by Science and Science's Online products to bring together a series of resources highlighting the importance and application of mathematics in biology. In addition to several articles on the topic, STKE will host a Forum that will allow users to discuss modeling and simulation environments available for analysis of cellular signaling processes with the authors of the articles.

  3. STEM Focus in Innoventure Competition Theme

    SciTech Connect

    None

    2010-03-31

    This report documents the inclusion of the STEM focus in the annual competition theme for the Innoventure youth project. The STEM concepts have always played a part in the selection of the theme. However, this year, STEM is intentionally mentioned in the description of the theme to emphasize the importance of these concepts. This work is a part of the National Security Preparedness Project (NSPP), being performed under a Department of Energy (DOE)/National Nuclear Security Administration (NNSA) grant.

  4. School Focused Utility Programs in Texas 

    E-print Network

    Santos, B.; Negley, M.

    2012-01-01

    ? 2011 CLEAResult ? All rights reserved. School Focused Utility Programs in Texas ? 2011 CLEAResult ? All rights reserved. School and Local Government programs on behalf of: ? 2011 CLEAResult ? All rights reserved. Overview ? Tagos... and CLEAResult ? energy efficiency program implementers for utilities in Texas ? Who we are and what we do ? Energy Efficiency (EE) opportunities in schools ? Eligible EE Measures ? Ineligible EE measures ? Resources to help ? Educational Facilities...

  5. Breaking Bullseye's Symmetry for Axial Field Focusing

    NASA Astrophysics Data System (ADS)

    Armand, Damien; Hironaka, Yoshiyuki; Kanazawa, Syuta; Tominaga, Yoriko; Kadoya, Yutaka; Tanaka, Tomoko; Tanaka, Koichiro

    2015-05-01

    We propose a bullseye type device capable of coupling the incident linearly polarized THz waves and focusing the axial electric field component. In order to avoid the destructive interference of the axial field occurring at the center of classic bullseyes, we introduce a spatial ?-phase shift on half part of it. The device is a simpler alternative than the use of classic bullseyes illuminated by a radially polarized incidence wave for the generation of axial field.

  6. Neonatal necrotizing enterocolitis: a focus on.

    PubMed

    Pellegrini, M; Lagrasta, N; Garcìa Garcìa, C; Campos Serna, J; Zicari, E; Marzocca, G

    2002-01-01

    Necrotizing enterocolitis (NEC) is a multifactorial worldwide problem, representing the most frequent gastrointestinal emergency in neonates. Extremely common in preterm infants, it is also registered in fullterm low birth weight neonates. Despite extensive research, its etiopathogenesis is not completely understood and this neonatal disease remains associated with high morbidity and mortality rates. This review proposes an interdisciplinary focus on recent developments in NEC etiopathogenesis, diagnosis and management. PMID:12608653

  7. Isoelectric Focusing of Camel Milk Proteins

    Microsoft Academic Search

    J. Wangoh; Z. Farah; Z. Puhan

    1998-01-01

    The procedure for phenotyping of most genetic variants in cow milk was optimised for iso-elctric focusing (IEF) of camel milk proteins and milk from individual camels of different breeds was screened. The caseins obtained from IEF bands were also investigated by N-terminal sequencing. Camel milk casein was separated at different pH and the proteins in the whey obtained were then

  8. Focusing DIRC Design for Super B

    SciTech Connect

    Va'Vra, J.; /SLAC

    2009-12-17

    In this paper we present a new design of the Focusing DIRC for the Barrel PID to be used at the proposed Super-B factory. The new imaging optics is made of a solid Fused Silica block with a double folded optics using two mirrors, one cylindrical and one flat, focusing photons on a detector plane conveniently accessible for the detector access. The design assumes that the BaBar bar boxes are re-used without any modification, including the wedges and windows. Each bar box will have its own focusing block, which will contain 40 H-9500 (or H-8500) MaPMTs according to present thinking. There are 12 bar boxes in the entire detector, so the entire SuperB FDIRC system would have 480 MaPMTs. The design is very compact and therefore reduces sensitivity to the background. The chosen MaPMTs are fast enough to be able both to reject the background and to perform the chromatic correction. The 3D optics simulation is coded with the Mathematica program. The work in this paper was a basis of the LDRD proposal made to SLAC in 2009 [1].

  9. Nozzleless droplet formation with focused acoustic beams

    NASA Astrophysics Data System (ADS)

    Elrod, S. A.; Hadimioglu, B.; Khuri-Yakub, B. T.; Rawson, E. G.; Richley, E.

    1989-05-01

    The use of focused acoustic beams to eject discrete droplets of controlled diameter and velocity from a free-liquid surface is reported. No nozzles are involved. Droplet formation has been experimentally demonstrated over the frequency range of 5-300 MHz, with corresponding droplet diameters from 300 to 5 microns. For acoustic focusing elements having similar geometries, droplet diameter has been found to scale inversely with the acoustic frequency. A simple model is used to obtain analytical expressions for the key parameters of droplet formation and their scaling with acoustic frequency. Also reported is a more detailed theory which includes the linear propagation of the focused acoustic wave, the coupling of the acoustic fields to the initial surface velocity potential, and the subsequent dynamics of droplet formation. This latter phase is modeled numerically as an incompressible, irrotational process using a boundary integral vortex method. For simulations at 5 MHz, this numerical model is very successful in predicting the key features of droplet formation.

  10. Nozzleless droplets formation with focused acoustic beams

    NASA Astrophysics Data System (ADS)

    Elrod, S. A.; Hadimioglu, B.; Khuri-Yakub, B. T.; Rawson, E. G.; Quate, C. F.; Mansour, N. N.; Lundgren, T. S.

    1990-01-01

    We report the use of focused acoustic beams to eject discrete droplets of controlled diameter and velocity and from a free liquid surface. No nozzles are involved. Droplet formation has been experimentally demonstrated over the frequency range of 5 to 300 MHz, with corresponding droplet diameters from 300 to 5 microns. The physics of droplet formation is essentially unchanged over this frequency range. For acoustic focusing elements having similar geometries, droplet diameter has been found to scale inversely with acoustic frequency. We summarize the results of a simple model which is used to obtain analytical expressions for the key parameters of droplet formation and their scaling with acoustic frequency. We also describe a more detailed theory which includes the linear propagation of the focused acoustic wave and the subsequent non-linear hydrodynamics of droplet formation. This latter phase is modeled numerically as an incompressible, irrotational process using a boundary integral vortex method. For simulations at 5 MHz, this numerical model is very successful in predicting the key features of droplet formation.

  11. Carbonitriding of silicon using plasma focus device

    SciTech Connect

    Jabbar, S.; Khan, I. A.; Ahmad, R.; Zakaullah, M.; Pan, J. S. [Department of Physics, GC University, 54000 Lahore (Pakistan); Department of Physics, Plasma Physics Laboratory, Quaid-i-Azam University, Islamabad 45230 (Pakistan); Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A-STAR), 3 Research Link, Singapore 117602 (Singapore)

    2009-03-15

    Carbonitride thin films have been deposited on silicon substrate by the irradiation of energetic nitrogen ions emanated from dense plasma focus device. The carbon ions are ablated by the irradiation of relativistic electrons from the insert material (graphite) placed at the anode tip. The x-ray diffraction analysis demonstrates that a polycrystalline thin film consisting of various compounds such as Si{sub 3}N{sub 4}, SiC, and C{sub 3}N{sub 4} is formed on the silicon (100) substrate. Crystallinity of different compounds decreases with the increase in angular positions (0 deg., 10 deg., and 20 deg. ). Raman spectroscopy shows the appearance of graphitic and disordered bands with silicon nitride and silicon carbide indicating the formation of carbonitride. Raman spectra also indicate that broadening of bands increases with the increase in focus deposition shots, leading to the amorphization of the thin film. The amorphization of the thin films depends on the ion energy flux as well as on the sample angular position. The scanning electron microscopy exhibits the damaging of the substrate surface at 0 deg. angular position. The microstructure shows the tubular shape for higher ion dose (40 focus shots). At 10 deg. angular position, a two phase phenomenon is observed with the ordered phase in the solid solution. A smooth and uniform surface morphology showing a small cluster is observed for the 20 deg. angular position.

  12. TECHNICAL INTEGRATION ENVIRONMENTAL MANAGEMENT FOCUS AREAS

    SciTech Connect

    Carey R. Butler

    2001-10-01

    This contract involved a team of companies led by WPI (formerly the Waste Policy Institute). In addition to WPI, the team included four subcontractors--TRW (formerly BDM Federal), SAIC, Energetics, and the University of North Dakota Energy and Environmental Research Center (EERC). The team of companies functioned as a ''seamless team'' assembled to support the Environmental Management Program Focus Areas. Staff resources were applied in the following offices: Richland, Washington, Idaho Falls, Idaho, Morgantown, West Virginia, Grand Forks, North Dakota, Aiken, South Carolina, Gaithersburg, Maryland, and Blacksburg, Virginia. These locations represented a mixture of site support offices at the field focus area locations and central staff to support across the focus areas. The management of this dispersed resource base relied on electronic communication links to allow the team to function as a ''virtual office'' to address tasks with the best qualified staff matched to the task assignments. A variety of tasks were assigned and successfully completed throughout the life of the contract that involved program planning and analysis, program execution, program information management and communication and data transmission.

  13. Automatic Focus Adjustment of a Microscope

    NASA Technical Reports Server (NTRS)

    Huntsberger, Terrance

    2005-01-01

    AUTOFOCUS is a computer program for use in a control system that automatically adjusts the position of an instrument arm that carries a microscope equipped with an electronic camera. In the original intended application of AUTOFOCUS, the imaging microscope would be carried by an exploratory robotic vehicle on a remote planet, but AUTOFOCUS could also be adapted to similar applications on Earth. Initially control software other than AUTOFOCUS brings the microscope to a position above a target to be imaged. Then the instrument arm is moved to lower the microscope toward the target: nominally, the target is approached from a starting distance of 3 cm in 10 steps of 3 mm each. After each step, the image in the camera is subjected to a wavelet transform, which is used to evaluate the texture in the image at multiple scales to determine whether and by how much the microscope is approaching focus. A focus measure is derived from the transform and used to guide the arm to bring the microscope to the focal height. When the analysis reveals that the microscope is in focus, image data are recorded and transmitted.

  14. Impact of the wave number estimation in Underground Focusing SAR images

    Microsoft Academic Search

    Fernando Quivira; Jose Angel Martinez Lorenzo; Carey M. Rappaport

    2010-01-01

    This work studies the impact estimating soil wave number in Underground Focusing SAR imaging for tunnel detection applications. It is demonstrated that poor underground imaging results when wave refraction at the ground surface is neglected, but that incorporating refraction with sufficiently high estimates of soil dielectric constant produce clear target images. Using a wrong wave number for the soil incorrectly

  15. SYNTHETICALLY FOCUSED IMAGING TECHNIQUES IN SIMULATED AUSTENITIC STEEL WELDS USING AN ULTRASONIC PHASED ARRAY

    Microsoft Academic Search

    G. D. Connolly; M. J. S. Lowe; S. I. Rokhlin; J. A. G. Temple

    2010-01-01

    In austenitic steel welds employed in safety-critical applications, detection of defects that may propagate during service or may have occurred during welding is particularly important. In this study, synthetically focused imaging techniques are applied to the echoes received by phased arrays in order to reconstruct images of the interior of a simulated austenitic steel weld, with application to sizing and

  16. Synthetically Focused Imaging Techniques in Simulated Austenitic Steel Welds Using AN Ultrasonic Phased Array

    Microsoft Academic Search

    G. D. Connolly; M. J. S. Lowe; S. I. Rokhlin; J. A. G. Temple

    2010-01-01

    In austenitic steel welds employed in safety-critical applications, detection of defects that may propagate during service or may have occurred during welding is particularly important. In this study, synthetically focused imaging techniques are applied to the echoes received by phased arrays in order to reconstruct images of the interior of a simulated austenitic steel weld, with application to sizing and

  17. Fingerprint detection

    DOEpatents

    Saunders, George C. (Rt. 1, Box 428B, Espanola, NM 87532)

    1992-01-01

    A method for detection and visualization of latent fingerprints is provided and includes contacting a substrate containing a latent print thereon with a colloidal metal composition for time sufficient to allow reaction of said colloidal metal composition with said latent print, and preserving or recording the observable print. Further, the method for detection and visualization of latent fingerprints can include contacting the metal composition-latent print reaction product with a secondary metal-containing solution for time sufficient to allow precipitation of said secondary metal thereby enhancing the visibility of the latent print, and preserving or recording the observable print.

  18. Ovulation detection.

    PubMed

    Moghissi, K S

    1992-03-01

    Despite major achievements in elucidating many details of the physiologic processes of human reproduction during the past 2 decades, a simple, reliable, and inexpensive method for the prediction and detection of the time of ovulation is still not available. For clinical purposes, studies of BBT and biophysical and biochemical constituents of cervical mucus appear to be the most practical methods of ovulation detection. The development of rapid and easy-to-use urinary LH assays and steroid assay kits for measurement of urinary and salivary estrogen and progesterone or their metabolites may further improve the precision of ovulation timing. PMID:1576982

  19. Arteriosclerosis Detection

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The Veterans Administration Hospital used computer image-processing techniques to detect arteriosclerosis. Originally developed by Goddard Space Flight Center engineers to enhance spacecraft pictures, this device replaced the previous testing for this disease which was extremely painful and time consuming. With this instrument, computer detected edges are shown along with an estimate of location of pre-arteriosclerosis vessel wall. The difference between the two represents the relative amount of disease in the blood vessel. Instrumentation will be expanded again in 1976 to analyze the coronary arteries and the blood vessels of the retina.

  20. Emerging technology of synthetic aperture focusing for ultrasonic testing

    NASA Astrophysics Data System (ADS)

    Busse, L. J.; Doctor, S. R.; Collins, H. D.

    1984-06-01

    The capabilities of synthetic aperture focusing techniques for ultrasonic testing (SAFT-UT) as a nondestructive testing technique are presented. SAFT-UT is a digital ultrasonic imaging method, which can be adapted to many different materials, specimen geometries, and wave propagation modes. The process allows each point within the inspected volume to be focused upon by mathematically simulating the action of a lens, specifically formed for imaging that point in the volume. All points are therefore imaged at the maximum available resolution. The PNL effort in SAFT-UT is a continuation of a program started earlier by the NRC at the University of Michigan. The objectives of the present program are: (1) to engineer and evaluate a real-time flaw detection and imaging system based on SAFT-UT for inservice inspection of all required LWR components; (2) to establish calibration and field test procedures; (3) to demonstrate and validate the system through field reactor inspections, and (4) to gain ASME Code acceptance of the real-time SAFT-UT technique.