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1

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

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

2

A comparison of shock wave and sinusoidal-focused ultrasound-induced localized transfection of HeLa cells.  

PubMed

Both shock waves and sinusoidal continuous wave ultrasound can mediate DNA transfer into cells. The relative transfection efficiencies of different ultrasound modalities are unclear. The purpose of this paper is to compare the transfection efficiency of lithotripter shock waves and focused sinusoidal ultrasound in vitro. HeLa cells were transfected with beta-galactosidase and luciferase plasmid DNA reporter. Shock waves were generated by an electromagnetic sound source. Sixty to 360 pulses at 1 Hz pulse frequency were administered at 13, 16 or 19 kV capacitor voltage. Sinusoidal focused ultrasound was generated by a single focus piezoceramic air-backed disk transducer at a carrier frequency of 1.18 MHz operated in a pulsed mode. Compared to cells mixed with DNA only, shock waves induced up to eightfold more transfected cells at a cell viability of 5%, while sinusoidal-focused ultrasound induced up to 80-fold more transfected cells at a cell viability of 45%. The corresponding transfection efficiencies of the HeLa cells were 0.08% for shock waves and 3% for focused ultrasound. These results may contribute to the selection of the ultrasound modality as a localized, noninvasive and safe tool to mediate gene transfer. PMID:10626634

Huber, P E; Jenne, J; Debus, J; Wannenmacher, M F; Pfisterer, P

1999-11-01

3

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

E-print Network

.e. transdermal and transcranial) cavitation detection during BBB opening. After the intravenous administration a formidable challenge in drug delivery. The blood­brain barrier (BBB) prevents most neurological drugs from

Konofagou, Elisa E.

4

Microbubble-Size Dependence of Focused Ultrasound-Induced Blood–Brain Barrier Opening in Mice In Vivo  

Microsoft Academic Search

The therapeutic efficacy of neurological agents is severely limited, because large compounds do not cross the blood-brain barrier (BBB). Focused ultrasound (FUS) sonication in the presence of microbubbles has been shown to temporarily open the BBB, allowing systemically administered agents into the brain. Until now, polydispersed microbubbles (1-10 ??m in diameter) were used, and, therefore, the bubble sizes better suited

James J. Choi; Jameel A. Feshitan; Babak Baseri; Shougang Wang; Yao-Sheng Tung; Mark A. Borden

2010-01-01

5

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

NASA Astrophysics Data System (ADS)

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.

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

2010-03-01

6

Permeability assessment of the focused ultrasound-induced blood-brain barrier opening using dynamic contrast-enhanced MRI  

PubMed Central

Focused ultrasound (FUS) in conjunction with microbubbles has been shown to successfully open the blood–brain barrier (BBB) in the mouse brain. In this study, we compute the BBB permeability after opening in vivo. The spatial permeability of the BBB-opened region was assessed using dynamic contrast-enhanced MRI (DCE-MRI). The DCE-MR images were post-processed using the general kinetic model (GKM) and the reference region model (RRM). Permeability maps were generated and the Ktrans values were calculated for a predefined volume of interest in the sonicated and the control area for each mouse. The results demonstrated that Ktrans in the BBB-opened region (0.02 ± 0.0123 for GKM and 0.03 ± 0.0167 min?1 for RRM) was at least two orders of magnitude higher when compared to the contra-lateral (control) side (0 and 8.5 × 10?4 ± 12 × 10?4 min?1, respectively). The permeability values obtained with the two models showed statistically significant agreement and excellent correlation (R2 = 0.97). At histological examination, it was concluded that no macroscopic damage was induced. This study thus constitutes the first permeability assessment of FUS-induced BBB opening using DCE-MRI, supporting the fact that the aforementioned technique may constitute a safe, non-invasive and efficacious drug delivery method. PMID:20736501

Vlachos, F; Tung, Y-S; Konofagou, E E

2014-01-01

7

Microbubble-Size Dependence of Focused Ultrasound-Induced Blood-Brain Barrier Opening in Mice In Vivo  

PubMed Central

The therapeutic efficacy of neurological agents is severely limited, because large compounds do not cross the blood–brain barrier (BBB). Focused ultrasound (FUS) sonication in the presence of microbubbles has been shown to temporarily open the BBB, allowing systemically administered agents into the brain. Until now, polydispersed microbubbles (1–10 ?m in diameter) were used, and, therefore, the bubble sizes better suited for inducing the opening remain unknown. Here, the FUS-induced BBB opening dependence on microbubble size is investigated. Bubbles at 1–2 and 4–5 ?m in diameter were separately size-isolated using differential centrifugation before being systemically administered in mice (n = 28). The BBB opening pressure threshold was identified by varying the peak-rarefactional pressure amplitude. BBB opening was determined by fluorescence enhancement due to systemically administered, fluorescent-tagged, 3-kDa dextran. The identified threshold fell between 0.30 and 0.46 MPa in the case of 1–2 ?m bubbles and between 0.15 and 0.30 MPa in the 4–5 ?m case. At every pressure studied, the fluorescence was greater with the 4–5 ?m than with the 1–2 ?m bubbles. At 0.61 MPa, in the 1–2 ?m bubble case, the fluorescence amount and area were greater in the thalamus than in the hippocampus. In conclusion, it was determined that the FUS-induced BBB opening was dependent on both the size distribution in the injected microbubble volume and the brain region targeted. PMID:19846365

Choi, James J.; Feshitan, Jameel A.; Baseri, Babak; Wang, Shougang; Tung, Yao-Sheng; Borden, Mark A.; Konofagou, Elisa E.

2014-01-01

8

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

NASA Astrophysics Data System (ADS)

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.

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

2010-10-01

9

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

PubMed Central

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

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

2011-01-01

10

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

PubMed Central

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

Samiotaki, Gesthimani; Konofagou, Elisa E.

2014-01-01

11

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

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

T. Ikeda; Y. Matsumoto

2005-01-01

12

Gold-nanorod contrast-enhanced photoacoustic micro-imaging of focused-ultrasound induced blood-brain-barrier opening in a rat model  

NASA Astrophysics Data System (ADS)

In this study, we develop a novel photoacoustic imaging technique based on gold nanorods (AuNRs) for quantitatively monitoring focused-ultrasound (FUS) induced blood-brain barrier (BBB) opening in a rat model in vivo. This study takes advantage of the strong near-infrared absorption (peak at ~800 nm) of AuNRs and the extravasation tendency from BBB opening foci due to their nano-scale size to passively label the BBB disruption area. Experimental results show that AuNR contrast-enhanced photoacoustic microscopy (PAM) successfully reveals the spatial distribution and temporal response of BBB disruption area in the rat brains. The quantitative measurement of contrast enhancement has potential to estimate the local concentration of AuNRs and even the dosage of therapeutic molecules when AuNRs are further used as nano-carrier for drug delivery or photothermal therapy. The photoacoustic results also provide complementary information to MRI, being helpful to discover more details about FUS induced BBB opening in small animal models.

Wang, Po-Hsun; Liu, Hao-Li; Hsu, Po-Hung; Lin, Chia-Yu; Chris Wang, Churng-Ren; Chen, Pin-Yuan; Wei, Kuo-Chen; Yen, Tzu-Chen; Li, Meng-Lin

2012-06-01

13

Permeability dependence study of the focused ultrasound-induced blood-brain barrier opening at distinct pressures and microbubble diameters using DCE-MRI  

PubMed Central

Blood-brain barrier (BBB) opening using focused ultrasound (FUS) and microbubbles has been experimentally established as a non-invasive and localized brain drug delivery technique. In this study, the permeability of the opening is assessed in the murine hippocampus after the application of FUS at three different acoustic pressures and microbubble sizes. Using DCE-MRI, the transfer rates were estimated, yielding permeability maps and quantitative Ktrans values for a predefined region of interest. The volume of BBB opening according to the Ktrans maps was proportional to both the pressure and the microbubble diameter. A Ktrans plateau of approximately 0.05 min?1 was reached at higher pressures (0.45 and 0.60 MPa) for the larger-sized bubbles (4–5 and 6–8 µm), which was on the same order as the Ktrans of the epicranial muscle (no barrier). Smaller bubbles (1–2 µm) yielded significantly lower permeability values. A small percentage (7.5%) of mice showed signs of damage under histological examination, but no correlation with permeability was established. The assessment of the BBB permeability properties and their dependence on both the pressure and the microbubble diameter suggests that Ktrans maps may constitute an in vivo tool for the quantification of the efficacy of the FUS-induced BBB opening. PMID:21465543

Vlachos, Fotios; Tung, Yao-Sheng; Konofagou, Elisa

2013-01-01

14

Analysis of focused ultrasound-induced blood-brain barrier permeability in a mouse model of Alzheimer's disease using two-photon microscopy.  

PubMed

Transcranial focused ultrasound (FUS) can cause temporary, localized increases in blood-brain barrier (BBB) permeability for effective drug delivery to the brain. In pre-clinical models of Alzheimer's disease, FUS has successfully been used to deliver therapeutic agents and endogenous therapeutic molecules to the brain leading to plaque reduction and improved behavior. However, prior to moving to clinic, questions regarding how the compromised vasculature in Alzheimer's disease responds to FUS need to be addressed. Here, we used two-photon microscopy to study changes in FUS-mediated BBB permeability in transgenic (TgCRND8) mice and their non-transgenic littermates. A custom-built ultrasound transducer was attached to the skull, covering a cranial window. Methoxy-X04 was used to visualize amyloid deposits in vivo. Fluorescent intravascular dyes were used to identify leakage from the vasculature after the application of FUS. Dye leakage occurred in both transgenic and non-transgenic mice at similar acoustic pressures but exhibited different leakage kinetics. Calculation of the permeability constant demonstrated that the vasculature in the transgenic mice was much less permeable after FUS than the non-transgenic littermates. Further analysis demonstrated that the change in vessel diameter following FUS was lessened in amyloid coated vessels. These data suggest that changes in vessel diameter may be directly related to permeability and the presence of amyloid plaque may reduce the permeability of a vessel after FUS. This study indicates that the FUS parameters used for the delivery of therapeutic agents to the brain may need to be adjusted for application in Alzheimer's disease. PMID:25107692

Burgess, Alison; Nhan, Tam; Moffatt, Clare; Klibanov, A L; Hynynen, Kullervo

2014-10-28

15

Magnetic-resonance imaging for kinetic analysis of permeability changes during focused ultrasound-induced blood-brain barrier opening and brain drug delivery.  

PubMed

Focused ultrasound (FUS) with the presence of microbubbles has been shown to induce transient and local opening of the blood-brain barrier (BBB) for the delivery of therapeutic molecules which normally cannot penetrate into the brain. The success of FUS brain-drug delivery relies on its integration with in-vivo imaging to monitor kinetic change of therapeutic molecules into the brain. In this study, we developed a dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) technique for kinetic analysis of delivered molecules during FUS-BBB opening. Three kinetic parameters (Ktrans, Ve, Kep) were characterized dynamically to describe BBB-permeability at two FUS exposure conditions (0.4 or 0.8MPa) over 24h. Ktrans, defined as the influx volume transfer constant from plasma to EES, and Ve, the EES volume fraction, were both found to be pressure-dependent. Ktrans and Ve showed a peak increase of 0.0086-0.0131min(-1) (for 0.4-0.8MPa pressure), and 0.0431-0.0692, respectively, immediately after FUS exposure. Both parameters subsequently decreased exponentially as a function of time, with estimated half-lives of decay of 2.89-5.3 and 2.2-4.93h, respectively. The kinetics of Kep, defined as the efflux rate constant from the extracellular extravascular space (EES) to the plasma, were complementary to Ktrans, with an initial decrease from 0.2010 to 0.1901min(-1) followed by a significantly longer recovery time (half-life of 17.39-99.92h). Our observations strongly supported the existence of imbalanced and mismatched kinetics of influx (Ktrans) and efflux (Kep) between the plasma and EES, indicating the existence of directional permeability during FUS-BBB opening. We further showed that kinetic change determined by DCE-MRI correlated well with the concentration of Evans Blue (EB)-albumin (coefficient of 0.74-0.89). These findings suggest that MRI kinetic monitoring may serve as an alternative method for in-vivo monitoring of pharmacokinetics and pharmacodynamics (PK/PD) change of therapeutic agents during drug delivery to the brain, and provide useful information for future optimization of FUS-BBB opening. PMID:24969355

Chai, Wen-Yen; Chu, Po-Chun; Tsai, Meng-Yen; Lin, Yu-Chun; Wang, Jiun-Jie; Wei, Kuo-Chen; Wai, Yau-Yau; Liu, Hao-Li

2014-10-28

16

Improved astigmatic focus error detection method  

NASA Technical Reports Server (NTRS)

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.

Bernacki, Bruce E.

1992-01-01

17

Magnetoresistive flux focusing eddy current flaw detection  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

18

Magnetoresistive Flux Focusing Eddy Current Flaw Detection  

NASA Technical Reports Server (NTRS)

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 multi-layer 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.

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

2005-01-01

19

A Feed-forward Neural Network Algorithm to Detect Thermal Lesions Induced by High Intensity Focused Ultrasound in Tissue  

PubMed Central

Non-invasive ultrasound surgeries such as high intensity focused ultrasound have been developed to treat tumors or to stop bleeding. In this technique, incorporation of a suitable imaging modality to monitor and control the treatments is essential so several imaging methods such as X-ray, Magnetic resonance imaging and ultrasound imaging have been proposed to monitor the induced thermal lesions. Currently, the only ultrasound imaging technique that is clinically used for monitoring this treatment is standard pulse-echo B-mode ultrasound imaging. This paper describes a novel method for detecting high intensity focused ultrasound-induced thermal lesions using a feed forward neural-network. This study was carried on in vitro animal tissue samples. Backscattered radio frequency signals were acquired in real-time during treatment in order to detect induced thermal lesions. Changes in various tissue properties including tissue's attenuation coefficient, integrated backscatter, scaling parameter of Nakagami distribution, frequency dependent scatterer amplitudes and tissue vibration derived from the backscattered radio frequency data acquired 10 minutes after treatment regarding to before treatment were used in this study. These estimated parameters were used as features of the neural network. Estimated parameters of two sample tissues including two thermal lesions and their segmented B-mode images were used along with the pathological results as training data for the neural network. The results of the study shows that the trained feed forward neural network could effectively detect thermal lesions in vitro. Comparing the estimated size of the thermal lesion (9.6 mm × 8.5 mm) using neural network with the actual size of that from physical examination (10.1 mm × 9 mm) shows that we could detect high intensity focused ultrasound thermal lesions with the difference of 0.5 mm × 0.5 mm. PMID:23724369

Rangraz, Parisa; Behnam, Hamid; Shakhssalim, Naser; Tavakkoli, Jahan

2012-01-01

20

Ultrasound-induced release of micropallets with cells  

PubMed Central

Separation of selected adherent live cells attached on an array of microelements, termed micropallets, from a mixed population is an important process in biomedical research. We demonstrated that adherent cells can be safely, selectively, and rapidly released from the glass substrate together with micropallets using an ultrasound wave. A 3.3-MHz ultrasound transducer was used to release micropallets (500??m?×?500??m?×?300??m) with attached HeLa cells, and a cell viability of 92% was obtained after ultrasound release. The ultrasound-induced release process was recorded by a high-speed camera, revealing a proximate velocity of ?0.5?m/s. PMID:23152640

Guo, Sijia; Wang, Yuli; Allbritton, Nancy; Jiang, Xiaoning

2012-01-01

21

Preface to the Focus Issue: Chaos Detection Methods and Predictability  

NASA Astrophysics Data System (ADS)

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.

Gottwald, Georg A.; Skokos, Charalampos

2014-06-01

22

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

PubMed

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

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

2014-12-01

23

Complete Inhibition Of Ultrasound Induced Cytolysis In The Presence Of Inertial Cavitation  

NASA Astrophysics Data System (ADS)

The investigation of ultrasound for biotechnological applications including non-invasive surgery (HIFU), drug/gene delivery to cells (sonoporation) or through the skin (sonophoresis) and ultrasound assisted bioreactors has focused mainly on the physical effects of ultrasound. The beneficial effects of ultrasound rely on a number of application-dependent mechanisms, and may include tissue heating, acoustic streaming or cavitation. Although acoustic cavitation is necessary in some systems, cavitation bubbles simultaneously result in uncontrollable cell damage and cytolysis. Thus, the development of a number of biotechnological uses of ultrasound has been hampered by the necessity to constrain exposure parameters in order to prevent the occurrence of acoustic cavitation or to at least limit the detrimental effects of cavitation. The current study shows that non-toxic concentrations of specific n-alkyl solutes completely inhibit ultrasound induced cytolysis of in vitro suspensions of human leukemia cells (HL-60). Protection of the whole cell population from cytolysis is achieved even under extreme ultrasound exposure conditions that result in cytolysis of 100 % of the cell population in the absence of the n-alkyl solutes. Furthermore, the n-alkyl solutes did not hinder the process of inertial cavitation. This method may allow utilization of beneficial effects of ultrasound and cavitation while protecting cells from cavitation induced cytolysis and thereby presents new possibilities for ultrasound in medicine and biology.

Sostaric, Joe Z.; Miyoshi, Norio; Riesz, Peter; De Graff, William G.; Mitchell, James B.

2006-05-01

24

Computer-assisted detection of epileptiform focuses on SPECT images  

NASA Astrophysics Data System (ADS)

Epilepsy is a common nervous system disease often related to consciousness disturbances and muscular spasm which affects about 1% of the human population. Despite major technological advances done in medicine in the last years there was no sufficient progress towards overcoming it. Application of advanced statistical methods and computer image analysis offers the hope for accurate detection and later removal of an epileptiform focuses which are the cause of some types of epilepsy. The aim of this work was to create a computer system that would help to find and diagnose disorders of blood circulation in the brain This may be helpful for the diagnosis of the epileptic seizures onset in the brain.

Grzegorczyk, Dawid; Dunin-W?sowicz, Dorota; Mulawka, Jan J.

2010-09-01

25

Microchip UV absorbance detection applied to isoelectric focusing of proteins.  

PubMed

Isoelectric focusing (IEF) is considered as an attractive separation technique for biologically amphoteric compounds (e.g., proteins and peptides) based on their isoelectric point (pI). With the advancement in micromachining technology, microchip format IEF has attracted significant attention. Both single-point and whole column imaging detection (WCID) methods have been employed for analyzing the separation performance in a microchip. WCID is more favorable than single-point detection because the latter requires the focused bands to be mobilized and thus adds more complexity to the design and operation of such microchips. Fluorescence- and UV absorbance-based WCID have been successfully adapted in glass and PDMS microchips. We have developed polydimethylsiloxane (PDMS) microchips for IEF applications where UV-WCID is employed for evaluating the separation performance. The chips are designed for use in the iCE280 analyzer (Convergent Bioscience Inc., Toronto), for capillary-based IEF where UV-WCID is employed for analyzing the separation performance. Three kinds of microchips that have been successfully developed using standard soft lithography technology are described in detail. PMID:23329463

Ou, Junjie; Ren, Carolyn L

2013-01-01

26

Rotating flux-focusing eddy current probe for flaw detection  

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

27

Ultrasound-Induced Blood-Brain Barrier Opening  

PubMed Central

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

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

2014-01-01

28

A robust eyelash detection based on iris focus assessment  

Microsoft Academic Search

For accurate iris recognition, it is essential to detect eyelash regions and remove them for iris code generation, since eyelashes act as noise factors in the iris recognition. In addition, eyelash positions can be changed for enrollment and recognition and this may cause FR (false rejection). To overcome these problems, we propose a new method for detecting eyelashes in this

Byung Jun Kang; Kang Ryoung Park

2007-01-01

29

Determination of threshold energy dose for ultrasound-induced transdermal drug transport  

Microsoft Academic Search

Low-frequency (20 kHz) ultrasound has been shown to enhance transdermal transport of drugs, a phenomenon referred to as sonophoresis. In this paper, we report the threshold energy dose for ultrasound-induced transdermal drug transport. The threshold was determined by in vitro measurements of the dependence of sonophoretic enhancement on ultrasound parameters, including intensity, duty cycle, and exposure time. While the enhancement

Samir Mitragotri; Joanne Farrell; Hua Tang; Takaaki Terahara; Joseph Kost; Robert Langer

2000-01-01

30

Ultrasonic sensitivity of strain-insensitive fiber Bragg grating sensors and evaluation of ultrasound-induced strain.  

PubMed

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

Tsuda, Hiroshi; Kumakura, Kenji; Ogihara, Shinji

2010-01-01

31

Salient Region Detection by UFO: Uniqueness, Focusness and Objectness Peng Jiang 1  

E-print Network

Salient Region Detection by UFO: Uniqueness, Focusness and Objectness Peng Jiang 1 Haibin Ling 2 three important visual cues namely uniqueness, focusness and objectness (UFO). In particular, uniqueness, named UFO saliency, which

Ling, Haibin

32

Ultrasound-induced cellular uptake of plasmonic gold nanorods  

NASA Astrophysics Data System (ADS)

Delivery of contrast agents and their interaction with cells is emerging as an important tool in cancer imaging and therapy. An alternative to traditional molecular targeting schemes that induce endocytotic uptake of contrast agents in cells is presented here. Specifically, the application of high-intensity, focused ultrasound (HIFU) was used to enhance uptake of gold nanorods in pancreatic cancer cells in vitro. A significant increase was observed in gold nanorod uptake when cells were incubated with nanorods and treated with HIFU. Additionally, inclusion of liquid-filled, perfluorocarbon (PFC) microdroplets in cell samples incubated with nanorods and treated with HIFU exhibited greater uptake of gold over those samples exposed to HIFU without microdroplets. Furthermore, the level of acoustic pressure required to increase nanoparticle uptake did not significantly decrease cell viability. Therefore, improved intracellular delivery of nanoparticle contrast agents is possible using HIFU without compromising cell viability. Since nanoparticle delivery is mechanically induced, this method can apply to a broad range of cancer imaging and therapy applications.

Hannah, Alexander; Wilson, Katheryne; Homan, Kimberly; Emelianov, Stanislav

2011-03-01

33

Detection of liquid hazardous molecules using linearly focused Raman spectroscopy  

NASA Astrophysics Data System (ADS)

In security, it is an important issue to analyze hazardous materials in sealed bottles. Particularly, prompt nondestructive checking of sealed liquid bottles in a very short time at the checkpoints of crowded malls, stadiums, or airports is of particular importance to prevent probable terrorist attack using liquid explosives. Aiming to design and fabricate a detector for liquid explosives, we have used linearly focused Raman spectroscopy to analyze liquid materials in transparent or semi-transparent bottles without opening their caps. Continuous lasers with 532 nm wavelength and 58 mW/130 mW beam energy have been used for the Raman spectroscopy. Various hazardous materials including flammable liquids and explosive materials have successfully been distinguished and identified within a couple of seconds. We believe that our technique will be one of suitable methods for fast screening of liquid materials in sealed bottles.

Cho, Soo Gyeong; Chung, Jin Hyuk

2013-05-01

34

Optical monitoring of ultrasound-induced bioeffects in glass catfish.  

PubMed

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

Maruvada, Subha; Hynynen, Kullervo

2004-01-01

35

A phantom for visualization of three-dimensional drug release by ultrasound-induced mild hyperthermia  

PubMed Central

Purpose: Ultrasound-induced mild hyperthermia has advantages for noninvasive, localized and controlled drug delivery. In this study, a tissue-mimicking agarose-based phantom with a thermally sensitive indicator was developed for studying the spatial drug delivery profile using ultrasound-induced mild hyperthermia. Methods: Agarose powder, regular evaporated milk, Dulbecco's phosphate-buffered saline (DPBS), n-propanol, and silicon carbide powder were homogeneously mixed with low temperature sensitive liposomes (LTSLs) loaded with a self-quenched near-infrared (NIR) fluorescent dye. A dual-mode linear array ultrasound transducer was used for insonation at 1.54 MHz with a total acoustic power and acoustic pressure of 2.0 W and 1.5 MPa, respectively. After insonation, the dye release pattern in the phantom was quantified based on optical images, and the three-dimensional release profile was reconstructed and analyzed. A finite-difference time-domain-based algorithm was developed to simulate both the temperature distribution and spatial dye diffusion as a function of time. Finally, the simulated dye diffusion patterns were compared to experimental measurements. Results: Self-quenching of the fluorescent dye in DPBS was substantial at a concentration of 6.25 × 10?2 mM or greater. The transition temperature of LTSLs in the phantom was 35?°C, and the release reached 90% at 37?°C. The simulated temperature for hyperthermia correlated with the thermocouple measurements with a mean error between 0.03 ± 0.01 and 0.06 ± 0.02?°C. The R2 value between the experimental and simulated spatial extent of the dye diffusion, defined by the half-peak level in the elevation, lateral and depth directions, was 0.99 (slope = 1.08), 0.95 (slope = 0.99), and 0.80 (slope = 1.04), respectively, indicating the experimental and simulated dye release profiles were similar. Conclusions: The combination of LTSLs encapsulating a fluorescent dye and an optically transparent phantom is useful for visualizing and modeling drug release in vitro following ultrasound-induced mild hyperthermia. The coupled temperature simulation and dye-diffusion simulation tools were validated with the experimental system and can be used to optimize the thermal dose and spatial and temporal dye release pattern. PMID:23927360

Lai, Chun-Yen; Kruse, Dustin; Seo, Jai Woong; Kheirolomoom, Azadeh; Ferrara, Katherine W.

2013-01-01

36

Improving photoacoustic-guided optical focusing in scattering media by spectrally filtered detection  

NASA Astrophysics Data System (ADS)

We experimentally and numerically study the potential of photoacoustic-guiding for light focusing through scattering samples via wavefront-shaping and iterative optimization. We experimentally demonstrate that the focusing efficiency on an extended absorber can be improved by iterative optimization of the high frequency components of the broadband photoacoustic signal detected with a spherically focused transducer. We demonstrate more than 8-fold increase in the photoacoustic signal generated by a 30 microns wire using a narrow frequency band around 60MHz. We numerically confirm that such optimization leads to a smaller optical focus than using the low frequency content of the photoacoustic feedback.

Chaigne, Thomas; Gateau, Jérôme; Katz, Ori; Boccara, Claude; Gigan, Sylvain; Bossy, Emmanuel

2014-10-01

37

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

Microsoft Academic Search

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

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

2010-01-01

38

Kinematic and aerodynamic aspects of ultrasound-induced negative phonotaxis in flying Australian field crickets ( Teleogryllus oceanicus )  

Microsoft Academic Search

Negative phonotaxis is elicited in flying Australian field crickets,Teleogryllus oceanicus, by ultrasonic stimuli. Using upright tethered flying crickets, we quantitatively examined several kinematic and aerodynamic factors which accompany ultrasound-induced negative phonotactic behavior. These factors included three kinematic effects (hindwing wingbeat frequency, hindwing elevation and depression, and forewing tilt) and two aerodynamic effects (pitch and roll).1.Within two cycles following a 20

Michael L. May; Peter D. Brodfuehrer; Ronald R. Hoy

1988-01-01

39

Superthreshold behavior and threshold estimation of ultrasound-induced lung hemorrhage in pigs: Role of age dependency  

Microsoft Academic Search

Age-dependent threshold and superthreshold behavior of ultrasound-induced lung hemorrhage were investigated with 116 2.1 ± 0.3-kg neonate crossbred pigs (4.9 ± 1.6 days old), 103 10 ± 1.1-kg crossbred pigs (39 ± 5 days old), and 104 20 ± 1.2-kg crossbred pigs (58 ± 5 days old). Exposure conditions were: 3.1 MHz, 10-s exposure duration, 1-kHz pulse repetition frequency (PRF),

William D. O'Brien; Douglas G. Simpson; Moon-Ho Ho; Rita J. Miller; Leon A. Frizzell; James F. Zachary

2003-01-01

40

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

PubMed Central

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.

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

2013-01-01

41

Isoelectric Focusing, Blotting and Probing Methods for Detection and Identification of Monoclonal Proteins  

PubMed Central

Isoelectric focusing (IEF) is a technique of exquisite resolution and high sensitivity. When applied to human biological fluids using conventional protein stains it is capable of detecting down to about 100 mg of protein/L. When combined with blotting and probing techniques it can get down to less than 1 mg/L. The exquisite resolution enables a greater discrimination between the various immunoglobulin abnormalities encountered in the clinical laboratory. PMID:19841695

Cornell, Findley N

2009-01-01

42

Focused bulk ultrasonic waves generated by ring-shaped laser illumination and application to flaw detection  

NASA Astrophysics Data System (ADS)

Focused bulk ultrasonic waves have been generated in aluminum plates by surface irradiation with ring-shaped laser light. The waves are detected by a piezoelectric transducer. Compression and shear peak amplitudes drop quickly when the detector is moved away from the epicenter. This shows that strong focusing exists at the epicenter as the result of constructive interference of the waves generated by different parts of the ring. The focusing persists when the radius of the laser light is scanned over a large range, indicating that the elastic disturbance concentrates in depth along the ring's central axis. Numerical simulations are presented for comparison. The ``pencil-like'' acoustic wave structure is used to observe a sample plate with an artificial flaw. Strong new features including compress-shear mode conversion at the site of the flaw are observed. These features are used to locate the flaw within the sample.

Wang, Xiao; Littman, Michael G.; McManus, John B.; Tadi, Mohsen; Kim, Young Sik; Askar, Attila; Rabitz, Herschel

1996-10-01

43

Effect of Gravitational Focusing on Annual Modulation in Dark-Matter Direct-Detection Experiments  

NASA Astrophysics Data System (ADS)

The scattering rate in dark-matter direct-detection experiments should modulate annually due to Earth's orbit around the Sun. The rate is typically thought to be extremized around June 1, when the relative velocity of Earth with respect to the dark-matter wind is maximal. We point out that gravitational focusing can alter this modulation phase. Unbound dark-matter particles are focused by the Sun's gravitational potential, affecting their phase-space density in the lab frame. Gravitational focusing can result in a significant overall shift in the annual-modulation phase, which is most relevant for dark matter with low scattering speeds. The induced phase shift for light O(10) GeV dark matter may also be significant, depending on the threshold energy of the experiment.

Lee, Samuel K.; Lisanti, Mariangela; Peter, Annika H. G.; Safdi, Benjamin R.

2014-01-01

44

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

NASA Technical Reports Server (NTRS)

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).

Bernacki, Bruce E.; Mansuripur, M.

1992-01-01

45

Targeted drug delivery with focused ultrasound-induced blood-brain barrier opening using acoustically-activated nanodroplets  

E-print Network

University, New York 10027, NY, USA b Joint Department of Biomedical Engineering, University of North, Columbia University, New York, NY 10032, USA a b s t r a c ta r t i c l e i n f o Article history: Received Alzheimer's [1], Huntington's [2] and Parkinson's [3] diseases as well as brain cancers [4,5]. Various

Konofagou, Elisa E.

46

Neuronavigation-guided focused ultrasound-induced blood-brain barrier opening: A preliminary study in swine  

NASA Astrophysics Data System (ADS)

FUS-induced BBB opening is a promising technique for noninvasive and local delivery of drugs into the brain. Here we propose the novel use of a neuronavigation system to guide the FUS-induced BBB opening procedure, and investigate its feasibility in vivo in large animals. We developed an interface between the neuronavigator and FUS to allow guidance of the focal energy produced by the FUS transducer. The system was tested in 29 pigs by more than 40 sonication procedures and evaluated by MRI. Gd-DTPA concentration was quantitated in vivo by MRI R1 relaxometry and compared by ICP-OES assay. Brain histology after FUS exposure was investigated by HE and TUNEL staining. Neuronavigation could successfully guide the focal beam with comparable precision to neurosurgical stereotactic procedures (2.3 +/- 0.9 mm). FUS pressure of 0.43 MPa resulted in consistent BBB-opening. Neuronavigation-guided BBB-opening increased Gd-DTPA deposition by up to 1.83 mM (140% increase). MR relaxometry demonstrated high correlation to ICP-OES measurements (r2 = 0.822), suggesting that Gd-DTPA deposition can be directly measured by imaging. Neuronavigation could provide sufficient precision for guiding FUS to temporally and locally open the BBB. Gd-DTPA deposition in the brain could be quantified by MR relaxometry, providing a potential tool for the in vivo quantification of therapeutic agents in CNS disease treatment.

Liu, Hao-Li; Tsai, Hong-Chieh; Lu, Yu-Jen; Wei, Kuo-Chen

2012-11-01

47

3D topographic correction of the BSR heat flow and detection of focused fluid flow  

NASA Astrophysics Data System (ADS)

The bottom-simulating reflector (BSR) is a seismic indicator of the bottom of a gas hydrate stability zone. Its depth can be used to calculate the seafloor surface heat flow. The calculated BSR heat flow variations include disturbances from two important factors: (1) seafloor topography, which focuses the heat flow over regions of concave topography and defocuses it over regions of convex topography, and (2) the focused warm fluid flow within the accretionary prism coming from depths deeper than BSR. The focused fluid flow can be detected if the contribution of the topography to the BSR heat flow is removed. However, the analytical equation cannot solve the topographic effect at complex seafloor regions. We prove that 3D finite element method can model the topographic effect on the regional background heat flow with high accuracy, which can then be used to correct the topographic effect and obtain the BSR heat flow under the condition of perfectly flat topography. By comparing the corrected BSR heat flow with the regional background heat flow, focused fluid flow regions can be detected that are originally too small and cannot be detected using present-day equipment. This method was successfully applied to the midslope region of northern Cascadia subducting margin. The results suggest that the Cucumber Ridge and its neighboring area are positive heat flow anomalies, about 10%-20% higher than the background heat flow after 3D topographic correction. Moreover, the seismic imaging associated the positive heat flow anomaly areas with seabed fracture-cavity systems. This suggests flow of warm gas-carrying fluids along these high-permeability pathways, which could result in higher gas hydrate concentrations.

He, Tao; Li, Hong-Lin; Zou, Chang-Chun

2014-06-01

48

Detection of Cracks at Welds in Steel Tubing Using Flux Focusing Electromagnetic Probe  

NASA Technical Reports Server (NTRS)

The inspection of weldments in critical pressure vessel joints is a major concern in the nuclear power industry. Corrosive environments can speed the fatigue process and access to the critical area is often limited. Eddy current techniques have begun to be used to help overcome these obstacles [1]. As direct contact and couplants are not required, remote areas can be inspected by simply snaking an eddy current coil into the intake tube of the vessel. The drawback of the eddy current method has been the high sensitivity to small changes in the conductivity and permeability of the test piece which are known to vary at weldments [1]. The flaw detection mechanism of the flux focusing electromagnetic probe can help alleviate these difficulties and provide a unique capability for detecting longitudinal fatigue cracks in critical tube structures. The Flux Focusing Electromagnetic Flaw Detector, originally invented for the detection of fatigue and corrosion damage in aluminum plates [2-3], has been adapted for use in testing steel tubing for longitudinal fatigue cracks. The modified design allows for the probe to be placed axisymmetrically into the tubing, inducing eddy currents in the tube wall. The pickup coil of the probe is fixed slightly below the primary windings and is rotated 90 so that its axis is normal to the tube wall. The magnetic flux of the primary coil is focused through the use of ferromagnetic material so that in the absence of fatigue damage there will be no flux linkage with the pickup coil. The presence of a longitudinal fatigue crack will cause the eddy currents induced in the tube wall to flow around the flaw and directly under the pickup coil. The magnetic field associated with these currents will then link the pickup coil and an unambiguous increase in the output voltage of the probe will be measured. The use of the flux focusing electromagnetic probe is especially suited for the detection of flaws originating at or near tube welds. The probe is shown to discriminate against signals due solely to the weld joint so that flaw signals are not hidden in the background in these locations. Experimental and finite element modeling results are presented for the flaw detection capabilities of the probe in stainless steel tubes.

Wincheski, Buzz; Fulton, Jim; Nath, Shridhar; Simpson, John; Namkung, Min

1994-01-01

49

Flexible integration of high-imaging-resolution and high-power arrays for ultrasound-induced thermal strain imaging (US-TSI).  

PubMed

Ultrasound-induced thermal strain imaging (USTSI) for carotid artery plaque detection requires both high imaging resolution (<100 ?m) and sufficient US-induced heating to elevate the tissue temperature (~1°C to 3°C within 1 to 3 cardiac cycles) to produce a noticeable change in sound speed in the targeted tissues. Because the optimization of both imaging and heating in a monolithic array design is particularly expensive and inflexible, a new integrated approach is presented which utilizes independent ultrasound arrays to meet the requirements for this particular application. This work demonstrates a new approach in dual-array construction. A 3-D printed manifold was built to support both a high-resolution 20 MHz commercial imaging array and 6 custom heating elements operating in the 3.5 to 4 MHz range. For the application of US-TSI in carotid plaque characterization, the tissue target site is 20 to 30 mm deep, with a typical target volume of 2 mm (elevation) × 8 mm (azimuthal) × 5 mm (depth). The custom heating array performance was fully characterized for two design variants (flat and spherical apertures), and can easily deliver 30 W of total acoustic power to produce intensities greater than 15 W/cm(2) in the tissue target region. PMID:24297029

Stephens, Douglas N; Mahmoud, Ahmed M; Ding, Xuan; Lucero, Steven; Dutta, Debaditya; Yu, Francois T H; Chen, Xucai; Kim, Kang

2013-12-01

50

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

PubMed

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

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

2006-09-01

51

Focused bulk ultrasonic waves generated by ring-shaped laser illumination and application to flaw detection  

SciTech Connect

Focused bulk ultrasonic waves have been generated in aluminum plates by surface irradiation with ring-shaped laser light. The waves are detected by a piezoelectric transducer. Compression and shear peak amplitudes drop quickly when the detector is moved away from the epicenter. This shows that strong focusing exists at the epicenter as the result of constructive interference of the waves generated by different parts of the ring. The focusing persists when the radius of the laser light is scanned over a large range, indicating that the elastic disturbance concentrates in depth along the ring{close_quote}s central axis. Numerical simulations are presented for comparison. The {open_quote}{open_quote}pencil-like{close_quote}{close_quote} acoustic wave structure is used to observe a sample plate with an artificial flaw. Strong new features including compress-shear mode conversion at the site of the flaw are observed. These features are used to locate the flaw within the sample. {copyright} {ital 1996 American Institute of Physics.}

Wang, X.; Littman, M.G. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)] [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); McManus, J.B. [Aerodyne Research, Inc., Billerica, Massachusetts 01821-3976 (United States)] [Aerodyne Research, Inc., Billerica, Massachusetts 01821-3976 (United States); Tadi, M.; Kim, Y.S.; Askar, A.; Rabitz, H. [Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)] [Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)

1996-10-01

52

Radially Focused Eddy Current Sensor for Detection of Longitudinal Flaws in Metallic Tubes  

NASA Technical Reports Server (NTRS)

A radially focused eddy current sensor detects longitudinal flaws in a metal tube. A drive coil induces eddy currents within the wall of the metal tube. A pick-up cod is spaced apart from the drive coil along the length of the metal tube. The pick@up coil is positioned with one end thereof lying adjacent the wall of the metal tube such that the pick-up coil's longitudinal axis is perpendicular to the wall of the metal tube. To isolate the pick-up coil from the magnetic flux of the drive coil and the flux from the induced eddy currents. except the eddy currents diverted by a longitudinal flaw. an electrically conducting material high in magnetic permeability surrounds all of the pick-up coil except its one end that is adjacent the walls of the metal tube. The electrically conducting material can extend into and through the drive coil in a coaxial relationship therewith.

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

1999-01-01

53

Femtomolar concentration detection limit and zeptomole mass detection limit for protein separation by capillary isoelectric focusing and laser-induced fluorescence detection.  

PubMed

Fluorescence tends to produce the lowest detection limits for most forms of capillary electrophoresis. Two issues have discouraged its use in capillary isoelectric focusing. The first issue is fluorescent labeling of proteins. Most labeling reagents react with lysine residues and convert the cationic residue to a neutral or anionic product. At best, these reagents perturb the isoelectric point of the protein. At worse, they convert each protein into hundreds of different fluorescent products that confound analysis. The second issue is the large background signal generated by impurities within commercial ampholytes. This background signal is particularly strong when excited in the blue portion of the spectrum, which is required by many common fluorescent labeling reagents. This paper addresses these issues. For labeling, we employ Chromeo P540, which is a fluorogenic reagent that converts cationic lysine residues to cationic fluorescent products. The reaction products are excited in the green, which reduces the background signal generated by impurities present within the ampholytes. To further reduce the background signal, we photobleach ampholytes with high-power photodiodes. Photobleaching reduced the noise in the ampholyte blank by an order of magnitude. Isoelectric focusing performed with photobleached pH 3-10 ampholytes produced concentration detection limits of 270 +/- 25 fM and mass detection limits of 150 +/- 15 zmol for Chromeo P540 labeled beta-lactoglobulin. Concentration detection limits were 520 +/- 40 fM and mass detection limits were 310 +/- 30 zmol with pH 4-8 ampholytes. A homogenate was prepared from a Barrett's esophagus cell line and separated by capillary isoelectric focusing, reproducibly generating dozens of peaks. The sample taken for the separation was equal to the labeled protein homogenate from three cells. PMID:19206532

Ramsay, Lauren M; Dickerson, Jane A; Dada, Oluwatosin; Dovichi, Norman J

2009-03-01

54

Corrosion Detection in Airframes Using a New Flux-Focusing Eddy Current Probe  

NASA Technical Reports Server (NTRS)

A new flux-focusing eddy current probe was recently developed at NASA Langley Research Center. The new probe is similar in design to a reflection type eddy current probe, but is unique in that it does not require the use of an impedance bridge for balancing. The device monitors the RMS output voltage of a pickup coil and, as a result, is easier to operate and interpret than traditional eddy current instruments. The unique design feature of the probe is a ferromagnetic cylinder, typically 1020 steel, which separates a concentrically positioned drive and pickup coil. The increased permeability of the steel causes the magnetic flux produced by the drive coil to be focused in a ring around the pickup coil. At high frequencies the eddy currents induced in both the sample and the cylinder allow little or no flux to link with the pickup coil. This results in a self-nulling condition which has been shown to be useful for the unambiguous detection of cracks in conducting materials. As the frequency is lowered the flux produced by the drive coil begins to link with the pickup coil causing an output which, among other things, is proportional to the thickness of the test specimen. This enables highly accurate measurements of the thickness of conducting materials and helps to facilitate the monitoring of thickness variations in a conducting structure such as an aircraft fuselage. Under ideal laboratory conditions the probe can sense thickness changes on the order of 1% as illustrated. However, this is highly dependent upon the thickness, and the geometric complexity of the sample being tested and for practical problems the sensitivity is usually much less. In this presentation we highlight some of the advantages and limitations in using the probe to inspect aircraft panels for corrosion and other types of material nonuniformities. In particular, we present preliminary results which illustrate the probes capabilities for detecting first and second layer corrosion in aircraft panels which may contain air gaps between the layers. Since the probe utilized eddy currents its corrosion detection capabilities are similar to convectional eddy current techniques, but the new probe is much easier to use.

Fulton, James P.; Wincheski, Buzz; Nath, Shridhar; Namkung, Min

1994-01-01

55

The role of heating, cavitation and acoustic streaming in mediating ultrasound-induced changes of TGF-beta gene expression in bone cells  

NASA Astrophysics Data System (ADS)

This paper relates ultrasound-induced changes in bone cell function to quantitative data assessing the level of several interaction mechanisms within the exposure environment. Characterisation of ultrasound fields in terms of resultant levels of heating, cavitation and acoustic streaming may provide a novel means of accurately assessing the likelihood of biological effects in vitro.

Harle, J.; Mayia, F.

2004-01-01

56

Ultrasound-induced controllable morphology and growth dimension in a dihydrazide-based self-assembly system.  

PubMed

We have demonstrated ultrasound-induced organogels based on twin-tapered dihydrazide derivatives, oxalyl acid N,N-di(3,4,5-trialkoxybenzoyl)hydrazide (FH-Tn). Ultrasound irradiation has been proved to influence gel properties at micro-levels. Different self-assembled structures from entangled fibers to tube-like structures and nanoparticles can be easily manipulated by tuning irradiation time and water bath temperature. FT-IR spectra exhibit weakened hydrogen bonding interactions, and XRD studies showed different packing modes before and after sonication. In addition, ultrasound can have effects on gel properties at macro-levels. Gels obtained from ultrasound treatment possess different wetting properties, relatively worse rheological properties and thermo-stability. Kinetic studies based on dynamic fluorescence spectra, rheological studies and theoretical calculations suggest that molecular aggregation mode differed from one-dimension to two-dimension for the gel after sonication. PMID:25283797

Zhang, Yan; Ding, Hao; Wu, Yangfang; Zhang, Chunxue; Bai, Binglian; Wang, Haitao; Li, Min

2014-10-23

57

Computer-aided tissue characterization using ultrasound-induced thermal effects: analytical formulation and in-vitro animal study  

NASA Astrophysics Data System (ADS)

Ultrasound radio-frequency (RF) time series analysis provides an effective tissue characterization method to differentiate between healthy and cancerous prostate tissues. In this paper, an analytical model is presented that partially describes the variations in tissue acoustic properties that accompany ultrasound RF time series acquisition procedures. These ultrasound-induced effects, which depend on tissue mechanical and thermophysical properties, are hypothesized to be among the major contributors to the tissue typing capabilities of the RF time series analysis. The model is used to derive two tissue characterization features. The two features are used with a support vector machine classifier to characterize three animal tissue types: chicken breast, bovine liver, and bovine steak. Accuracy values as high as 90% are achieved when the proposed features are employed to differentiate these tissue types. The proposed model may provide a framework to optimize the ultrasound RF time series analysis for future clinical procedures.

Daoud, Mohammad I.; Mousavi, Parvin; Imani, Farhad; Rohling, Robert; Abolmaesumi, Purang

2011-03-01

58

Hand-held forward-looking focused array mine detection with plane wave excitation  

NASA Astrophysics Data System (ADS)

A novel handheld time-domain array GPR antipersonnel mine detection system prototype has been developed. Using an offset paraboloidal reflector antenna to collimate rays form an ultra-wideband feed, the transmitted microwave impulse is concentrated forward, in front of the antenna structure. The resulting wave is a non-uniform plane wave over the portion of ground be investigated, and is incident at 45 degrees to normal. As such, much of the ground reflect wave is directed further forward, away from the operator, the reflector, and the receiving antennas, thereby reducing clutter. However, the wave transmitted into the ground, which interacts with the target, tends to have significant backscatter returning toward the receiving antennas. These receiving antennas are configured in a 2 by 2 array to provide spatial focusing in both along and cross-track directions. This is accomplished by measuring and comparing the backscattered signal at each receiver in the narrow time window between the times when the ground reflected wave passes the receiver and before this wave re-reflects from the reflector components. 2D FDTD simulation of this parabolic reflector transmitter indicates that it generates a beam with a non-uniform planar wavefront, which scatters form rough ground primarily in the forward direction. The wave transmitted into the ground is also planar, propagating at the angle of refraction, and scattering fairly isotropically from a small penetrable target. This system has been built and tested at LLNL, using a very narrow pulse shape. LLNL's Micro-Impulse Radar (MIR) and custom-built wideband antenna elements operate in the 1.5 to 5 GHz range. One particular advantage of using the MIR module is its low cost: an important feature for mine detectors used in developing countries. Preliminary measured data indicates that the surface clutter is indeed reduced relative to the target signal, and that small non-metallic anti-personnel mines can be reliably detected at burial depths as shallow as 1 inch in both dry.

Rappaport, Carey M.; Azevedo, Stephen G.; Rosenbury, Tom; Gough, Jamie; Jin, Dongping

2000-08-01

59

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

PubMed

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

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

2006-12-15

60

Sensitive detection of transglycosylating activity of xyloglucan endotransglycosylase\\/hydrolase (XTH) after isoelectric focusing in polyacrylamide gels  

Microsoft Academic Search

The paper describes a sensitive and rapid zymogram technique for detection of transglycosylating activity (XET) of xyloglucan endotransglycosylase\\/hydrolase (XTH; EC 2.4.1.207) in polyacrylamide isoelectric focusing gels. After the electrophoresis, the separating gel was overlaid and incubated with an agarose detection gel containing XET substrates: tamarind-seed xyloglucan as the glycosyl donor and sulphorhodamine-labeled xyloglucan-derived oligosaccharides (XGO-SRs) as the glycosyl acceptors. The

Vladimír Farkaš; Fairouz Ait-Mohand; Eva Stratilová

2005-01-01

61

Auditory helicopter detection and localization; a literature review focusing on search for helicopters  

Microsoft Academic Search

About 300 references on auditory localization were reviewed. Detection of low frequency sound is discussed. Literature shows that man's ability to localize sounds by auditory detection is good. Vision may also assist the auditory localization. A helicopter approaching at a great height (1500 feet) is easier to localize than a low flying one (200 feet), and a helicopter heading into

C. Weikert

1986-01-01

62

PHYSICAL REVIEW E 88, 023006 (2013) Ultrasound-induced acoustophoretic motion of microparticles in three dimensions  

E-print Network

-induced drag force. In contrast to the classical theory of Rayleigh streaming in shallow, infinite, parallel-plate microchannels, instead the focus has been on the idealized parallel-plate geometry [9­14] or single-wall systems, rectangular microchannel actuated in one of its transverse standing ultrasound-wave resonance modes with one

63

A New Approach for Detecting Attenuation Changes During High-Intensity Focused  

E-print Network

-invasive treatment modality. Despite the many advantages of HIFU for thermal therapy, obstacles remain in translating characterization in general, and is needed for planning of High-Intensity Focused Ultrasound (HIFU) therapy potentially be used for both monitoring and assessment of HIFU therapy. This approach compares the signal

Illinois at Urbana-Champaign, University of

64

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

PubMed

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

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

2007-03-01

65

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

Microsoft Academic Search

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

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

2006-01-01

66

Detection of Silver Nanoparticles inside Marine Diatom Thalassiosira pseudonana by Electron Microscopy and Focused Ion Beam  

PubMed Central

In the following article an electron/ion microscopy study will be presented which investigates the uptake of silver nanoparticles (AgNPs) by the marine diatom Thalassiosira pseudonana, a primary producer aquatic species. This organism has a characteristic silica exoskeleton that may represent a barrier for the uptake of some chemical pollutants, including nanoparticles (NPs), but that presents a technical challenge when attempting to use electron-microscopy (EM) methods to study NP uptake. Here we present a convenient method to detect the NPs interacting with the diatom cell. It is based on a fixation procedure involving critical point drying which, without prior slicing of the cell, allows its inspection using transmission electron microscopy. Employing a combination of electron and ion microscopy techniques to selectively cut the cell where the NPs were detected, we are able to demonstrate and visualize for the first time the presence of AgNPs inside the cell membrane. PMID:24797958

Pascual Garcia, Cesar; Burchardt, Alina D.; Carvalho, Raquel N.; Gilliland, Douglas; C. Antonio, Diana; Rossi, Francois; Lettieri, Teresa

2014-01-01

67

Improved detection of malnutrition by medical housestaff following focused-teaching intervention.  

PubMed

We examined the influence of a brief, small group teaching intervention, which used current patients as examples, on the detection of malnutrition by medical housestaff. We reviewed 100 consecutive patient admissions before and 61 admissions 1 month after the intervention for any mention of malnutrition in admitting, progress, or discharge notes and compared the result with the number of patients diagnosed as malnourished by dietitians. Before the intervention, interns correctly identified 4 (14%) of 28 malnourished patients. After the intervention, the same interns correctly identified 15 (94%) of 16 malnourished patients (p = .0004). We conclude that this brief teaching intervention was effective in increasing the awareness and detection of malnutrition by interns. PMID:8905506

Cheskin, L J; Fontaine, K R; Lasner, L A; Stridiron, C; Katz, P O

1996-09-01

68

Detection of silver nanoparticles inside marine diatom Thalassiosira pseudonana by electron microscopy and focused ion beam.  

PubMed

In the following article an electron/ion microscopy study will be presented which investigates the uptake of silver nanoparticles (AgNPs) by the marine diatom Thalassiosira pseudonana, a primary producer aquatic species. This organism has a characteristic silica exoskeleton that may represent a barrier for the uptake of some chemical pollutants, including nanoparticles (NPs), but that presents a technical challenge when attempting to use electron-microscopy (EM) methods to study NP uptake. Here we present a convenient method to detect the NPs interacting with the diatom cell. It is based on a fixation procedure involving critical point drying which, without prior slicing of the cell, allows its inspection using transmission electron microscopy. Employing a combination of electron and ion microscopy techniques to selectively cut the cell where the NPs were detected, we are able to demonstrate and visualize for the first time the presence of AgNPs inside the cell membrane. PMID:24797958

García, César Pascual; Burchardt, Alina D; Carvalho, Raquel N; Gilliland, Douglas; António, Diana C; Rossi, François; Lettieri, Teresa

2014-01-01

69

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

PubMed

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

Elbers, Armin; Knutsson, Rickard

2013-09-01

70

Detection theory applied to high intensity focused ultrasound (HIFU) treatment evaluation  

NASA Astrophysics Data System (ADS)

The aim of this work is to develop a HIFU treatment evaluation algorithm based on 1-D pulse/echo (P/E) ultrasound data taken during HIFU exposures. The algorithm is applicable to large treatment volumes resulting from several overlapping elementary exposures. Treatments consisted of multiple HIFU exposures with an on-time of 3 seconds each, spaced 3 mm apart, and an off-time of 6 seconds in between HIFU exposures. The HIFU was paused for approximately 70 milliseconds every 0.5 seconds, while P/E data was acquired along the beam axis, using a confocal imaging transducer. Data was collected from multiple in vitro and in vivo tissue treatments, including shams. The cumulative energy change in the P/E data was found for every HIFU exposure, as a function of depth. Subsequently, a likelihood ratio test with a fixed false alarm rate was used to derive a positive or negative lesion creation decision for that position. For false alarm rates less than 5%, positive treatment outcomes were consistently detected for better than 90% of the HIFU exposures. In addition, the algorithm outcome correlated to the applied HIFU intensity level. Lesion formation was therefore successfully detected as a function of dosage. [Work supported by NIH SBIR Grant 2 R 44 CA 83244-02.

Sanghvi, Narendra; Wunderlich, Adam; Seip, Ralf; Tavakkoli, Jahangir; Dines, Kris; Baily, Michael; Crum, Lawrence

2003-04-01

71

Optimization of the Ultrasound-Induced Blood-Brain Barrier Opening  

PubMed Central

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

Konofagou, Elisa E.

2012-01-01

72

Ultrasound-induced DNA damage and signal transductions indicated by gammaH2AX  

NASA Astrophysics Data System (ADS)

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.

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

73

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

NASA Astrophysics Data System (ADS)

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.

Query, Michael Earl

74

Modelling ultrasound-induced mild hyperthermia of hyperplasia in vascular grafts  

PubMed Central

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

2011-01-01

75

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

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

76

Two-dimensional capillary electrophoresis: capillary isoelectric focusing and capillary zone electrophoresis with laser-induced fluorescence detection  

PubMed Central

Capillary isoelectric focusing and capillary zone electrophoresis are coupled with laser-induced fluorescence detection to create an ultrasensitive two-dimensional separation method for proteins. In this method, two capillaries are joined through a buffer filled interface. Separate power supplies control the potential at the injection end of the first capillary and at the interface; the detector is held at ground potential. Proteins are labeled with the fluorogenic reagent Chromeo P503, which preserves the isoelectric point of the labeled protein. The labeled proteins were mixed with ampholytes and injected into the first dimension capillary. A focusing step was performed with the injection end of the capillary at high pH and the interface at low pH. To mobilize components, the interface was filled with a high pH buffer, which was compatible with the second dimension separation. A fraction was transferred to the second dimension capillary for separation. The process of fraction transfer and second dimension separation was repeated two dozen times. The separation produced a spot capacity of 125. PMID:20603830

Dickerson, Jane A.; Ramsay, Lauren M.; Dada, Oluwatosin O.; Cermak, Nathan

2011-01-01

77

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

PubMed Central

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

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

2013-01-01

78

Evaluation of Prognostic Integrin ?2?1 PET Tracer and Concurrent Targeting Delivery Using Focused Ultrasound for Brain Glioma Detection.  

PubMed

The ability to early detect and assess the treatment response of recurrent and/or disseminated metastatic glioblastoma is critical for the effective management of this group of patients. Accumulating experimental evidence indicates that integrin ?2?1 might be a prognostic biomarker for advanced phenotype of cancers. In this study, a novel (68)Ga-labeled integrin ?2?1-targeted PET tracer (68)Ga-NOTA-PEG4-cyclo (GDGEAyK) ((68)Ga-A2B1) was designed and evaluated for the potential prognostic imaging of glioblastoma tumor in preclinical model. To prospectively verify the prognostic value of integrin ?2?1, the in vitro Western blot and flow cytometry studies were performed to validate the integrin expression level of human glioblastoma (U87MG) cells. Extremely high expression level of integrin ?2?1 justifies its role as a potential targeting marker. Thus, (68)Ga-A2B1 positron emission tomography was performed in subcutaneous U87MG tumor bearing athymic mice at 15 min postinjection after injection of 7-8MBq tracers. The receptor targeting specificity was confirmed in a competition blocking experiment. The tumor uptake of (68)Ga-A2B1 in the control and blockage groups was 1.57 ± 0.13 %ID/g (n = 3) and 0.96 ± 0.23 %ID/g** (n = 3), respectively. However, because of the quick renal washout rate and labile nature of peptide tracers in circulation conditions, the focus ultrasound (FUS) mediated delivery method was adopted to enhance tumor uptake and retention of tracers. To test the FUS delivery efficacy in vivo, three experimental arms were designed as follows: tumor bearing mice were administrated with (68)Ga-A2B1 only or microbubbles (MBs) with FUS treatment ((68)Ga-A2B1 + FUS + MBs) or embedded (68)Ga-A2B1-microbubbles ((68)Ga-A2B1-MBs + FUS) followed with FUS sonication. The average radioactivity accumulation within a tumor was quantified from the multiple region of interest volumes using the %ID/g value and was analyzed in accordance with the ex vivo autoradiographic and pathologic data. The significant tumor uptake in (68)Ga-A2B1 + FUS +MBs group (n = 6) and (68)Ga-A2B1-MBs + FUS group (n = 4) following FUS treatment were calculated as 2.25 ± 0.50 %ID/g* and 2.6 ± 0.49 %ID/g**, comparing with (68)Ga-A2B1 only group 1.48 ± 0.42 %ID/g (n = 10). These results suggest that there is significant difference in (68)Ga-A2B1 tumor uptake by FUS treatment either with or without tracer integration with microbubbles, which demonstrate a promising delivery strategy and critical multimodal setting for phenotyping imaging of aggressive glioma tumor. In conclusion, (68)Ga labeled (68)Ga-A2B1 allows noninvasive imaging of tumor-associated ?2?1 expression and can be embedded in MB lipid shell for enhanced delivery and controlled release by sonoporation. PMID:25153169

Chung, Yi-Hsiu; Hsu, Po-Hung; Huang, Chiun-Wei; Hsieh, Wen-Chuan; Huang, Feng-Ting; Chang, Wen-Chi; Chiu, Han; Hsu, Shih-Ting; Yen, Tzu-Chen

2014-11-01

79

High-precision topography measurement through accurate in-focus plane detection with hybrid digital holographic microscope and white light interferometer module.  

PubMed

High-precision topography measurement of micro-objects using interferometric and holographic techniques can be realized provided that the in-focus plane of an imaging system is very accurately determined. Therefore, in this paper we propose an accurate technique for in-focus plane determination, which is based on coherent and incoherent light. The proposed method consists of two major steps. First, a calibration of the imaging system with an amplitude object is performed with a common autofocusing method using coherent illumination, which allows for accurate localization of the in-focus plane position. In the second step, the position of the detected in-focus plane with respect to the imaging system is measured with white light interferometry. The obtained distance is used to accurately adjust a sample with the precision required for the measurement. The experimental validation of the proposed method is given for measurement of high-numerical-aperture microlenses with subwavelength accuracy. PMID:24787417

Li?ewski, Kamil; Tomczewski, S?awomir; Kozacki, Tomasz; Kostencka, Julianna

2014-04-10

80

Qualitative and Quantitative Analysis of Molecular Delivery Through the Ultrasound-Induced Blood-Brain Barrier Opening in Mice  

NASA Astrophysics Data System (ADS)

Recent studies have proven that focused ultrasound (FUS) in the presence of microbubbles can deliver large molecules across the blood-brain barrier (BBB) locally, transiently and non-invasively. In this study, the cellular effects, the size estimation of the opening and the amount delivered were inferred through qualitative and quantitative analysis of molecular delivery to the brain parenchyma in a murine model. The ultimate purpose was to build the foundation for future ultrasound-facilitated neurodegenerative disease treatment in humans. A bolus of microbubbles at 1 ?l/g body weight concentration was intravenously injected. Pulsed FUS was applied to the left hippocampus through the intact skin and skull followed by intravenously administration of fluorescence-conjugated dextran at 3 kDa, 10 kDa and 70 kDa. The brain were either sectioned for fluorescence imaging or homogenized for quantitative analysis. The concentration of 3 kDa, 10 kDa and 70 kDa dextrans delivered to the left brain hemisphere was quantified to be 7.9±4.9 ?g/g, 2.4±1.3 ?g/g and 0.9±0.47 ?g/g of brain weight. Smooth muscle cells engulfing the arterioles exhibited higher fluorescence in the case of 70 kDa dextran, compared to the 3 kDa dextran, demonstrating that fluorescence imaging can help with the understanding of the type of mechanism of molecular uptake by different brain cells.

Wang, Shougang; Baseri, Babak; Choi, James J.; Tung, Yao-Sheng; Morrison, Barclay; Konofagou, Elisa E.

2009-04-01

81

Magnetic Resonance Thermometry at 7T for Real-Time Monitoring and Correction of Ultrasound Induced Mild Hyperthermia  

PubMed Central

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

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

82

Pharmacokinetics of BPA in Gliomas with Ultrasound Induced Blood-Brain Barrier Disruption as Measured by Microdialysis  

PubMed Central

The blood-brain barrier (BBB) can be transiently disrupted by focused ultrasound (FUS) in the presence of microbubbles for targeted drug delivery. Previous studies have illustrated the pharmacokinetics of drug delivery across the BBB after sonication using indirect visualization techniques. In this study, we investigated the in vivo extracellular kinetics of boronophenylalanine-fructose (BPA-f) in glioma-bearing rats with FUS-induced BBB disruption by microdialysis. After simultaneous intravenous administration of BPA and FUS exposure, the boron concentration in the treated brains was quantified by inductively coupled plasma mass spectroscopy. With FUS, the mean peak concentration of BPA-f in the glioma dialysate was 3.6 times greater than without FUS, and the area under the concentration-time curve was 2.1 times greater. This study demonstrates that intracerebral microdialysis can be used to assess local BBB transport profiles of drugs in a sonicated site. Applying microdialysis to the study of metabolism and pharmacokinetics is useful for obtaining selective information within a specific brain site after FUS-induced BBB disruption. PMID:24936788

Yang, Feng-Yi; Lin, Yi-Li; Chou, Fong-In; Lin, Yu-Chuan; Hsueh Liu, Yen-Wan; Chang, Lun-Wei; Hsieh, Yu-Ling

2014-01-01

83

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

PubMed

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

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

84

Molecules of various pharmacologically-relevant sizes can cross the ultrasound-induced blood-brain barrier opening in vivo  

PubMed Central

Focused ultrasound (FUS) is hereby shown to noninvasively and selectively deliver compounds at pharmacologically relevant molecular weights through the opened blood-brain barrier (BBB). A complete examination on the size of the FUS-induced BBB opening, the spatial distribution of the delivered agents and its dependence on the agent's molecular weight were imaged and quantified using fluorescence microscopy. BBB opening in mice (n=13) was achieved in vivo after systemic administration of microbubbles and subsequent application of pulsed FUS (frequency: 1.525 MHz, peak-rarefactional pressure in situ: 569 kPa) to the left murine hippocampus through the intact skin and skull. BBB-impermeant, fluorescent-tagged dextrans at three distinct molecular weights spanning over several orders of magnitude were systemically administered and acted as model therapeutic compounds. First, dextrans of 3 and 70 kDa were delivered trans-BBB while 2000 kDa dextran was not. Second, compared to 70 kDa dextran, a higher concentration of 3 kDa dextran was delivered through the opened BBB. Third, the 3 and 70 kDa dextrans were both diffusely distributed throughout the targeted brain region. However, high concentrations of 70 kDa dextran appeared more punctated throughout the targeted region. In conclusion, FUS combined with microbubbles opened the BBB sufficiently to allow passage of compounds of at least 70 kDa, but not greater than 2000 kDa, into the brain parenchyma. This noninvasive and localized BBB opening technique could thus provide a unique means for the delivery of compounds of several magnitudes of kDa that include agents with shown therapeutic promise in vitro, but whose in vivo translation has been hampered by their associated BBB impermeability. PMID:19900750

Choi, James J.; Wang, Shougang; Tung, Yao-Sheng; Morrison, Barclay; Konofagou, Elisa E.

2009-01-01

85

Geoscientific Applications of Particle Detection and Imaging Techniques withSpecial Focus on the Monitoring Clay Mineral Reactions  

NASA Astrophysics Data System (ADS)

The combined use of focused X-ray, electron, and ion beams offers a diverse range of analytical capabilities for characterizing nanoscale mineral reactions that occur in hydrous environments. Improved image and microanalytical techniques (e.g., electron diffraction and energy-dispersive X-ray spectroscopy), in combination with controlled sample environments, are currently leading to new advances in the understanding of fluid-mineral reactions in the Earth Sciences. One group of minerals playing a key role in the containment of radioactive waste and the underground storage of CO2 is the clay minerals: these small, expandable, and highly adsorbent hydrous phyllosilicates form important low-permeable geological barriers by which waste can be safely deposited. In this article we summarize some of the state-of-the-art particle and imaging techniques employed to predict the behavior of both engineered and natural clay mineral seals in proposed storage sites. Particular attention is given to two types of low-permeability geomaterials: engineered bentonite backfill and natural shale in the subsurface. These materials have contrasting swelling properties and degrees of chemical stability that require detailed analytical study for developing suitable disposal or storage solutions.

Warr, Laurence N.; Grathoff, Georg H.

86

Attention focusing in a sit-and-wait forager: a spider controls its prey-detection ability in different web sectors by adjusting thread tension  

PubMed Central

Focusing attention is a way for animals to search for and to obtain food efficiently. This study examines whether a sit-and-wait forager, the orb-web spider Cyclosa octotuberculata, focuses its attention on limited foraging areas. Video records of foraging activity revealed that the spiders detected prey trapped in the west and east sectors of their web less frequently than prey trapped in the north and south sectors. Comparison of photos of the web hub area with and without spiders present revealed that the spiders pulled radii towards the centre when waiting for prey. Radius pulling is stronger in the north and south web sectors than in the west and east sectors, possibly causing more tension in radii running vertically. Experimental manipulation indicated that the spiders responded to prey quicker when thread tension was increased. The results suggest that C. octotuberculata focus their attention on the web areas above and below the spider by adjusting the tension in web threads; and this causes higher prey detection rates in these areas. PMID:19812081

Nakata, Kensuke

2010-01-01

87

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

NASA Astrophysics Data System (ADS)

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.

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

2011-05-01

88

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)

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.

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

2014-06-01

89

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

PubMed

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

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

2006-07-01

90

Detection of Leishmania infantum and identification of blood meals in Phlebotomus perniciosus from a focus of human leishmaniasis in Madrid, Spain.  

PubMed

Since 2010, the number of cases of both human visceral leishmaniasis and cutaneous leishmaniasis in southwestern Madrid region (Spain) and more specifically in the town of Fuenlabrada has increased. Direct xenodiagnosis of leishmaniasis proved that hares (Lepus granatensis) from this focus are able to infect with Leishmania infantum colonized Phlebotomus perniciosus. To a better understanding of this focus of leishmaniasis, we conducted an entomological survey using CDC light traps, at the end of the seasonal transmission period of 2011 before the beginning of control measures of the disease, to study the phlebotomine sand flies species involved. Detection of Leishmania DNA in the sand flies captured was studied by kDNA-PCR and cpb-PCR. In addition, blood fed and gravid female P. perniciosus were analysed by a PCR based in vertebrate cytochrome b (cyt b) gene. Taxonomic identification of captured sand flies (n = 174) as P. perniciosus (n = 171) and Sergentomyia minuta (n = 3) together with the analysis of blood feeding in ten sand flies that shows a high preference for hares (n = 6), followed by humans (n = 3), and cats (n = 1) confirm a strong association between P. perniciosus hares and humans in the focus. Moreover, 79 out of 135 (58.5 %) P. perniciosus were positive to L. infantum by PCR approaches. These data support the increase of human leishmaniasis cases in the area and the existence of an unusual sylvatic cycle alternative to the classical domestic one, where the dog is the main reservoir of L. infantum. PMID:23535889

Jiménez, Maribel; González, Estela; Iriso, Andrés; Marco, Elisa; Alegret, Ana; Fúster, Fernando; Molina, Ricardo

2013-07-01

91

Multispectral photoacoustic imaging of tissue denaturation induced by high-intensity focused ultrasound treatment  

NASA Astrophysics Data System (ADS)

This paper presents an ex vivo study in imaging high-intensity focused ultrasound induced tissue denaturation with multispectral photoacoustic approach. Beef tissues treated by both water bath and high-intensity focused ultrasound were imaged and evaluated by photoacoustic imaging method, where light in multiple optical wavelengths between 700nm and 900nm is applied. Tissue denaturation after being treated by water bath and high-intensity focused ultrasound has been observed in multispectral photoacoustic images. The denaturation is more striking in relatively shorter optical wavelength photoacoustic images than in relatively longer optical wavelength photoacoustic images. This study suggests that multispectral photoacoustic imaging method is promising in the evaluation of tissue denaturation induced by high- intensity focused ultrasound treatment.

Sun, Yao; Li, King C. P.; O'Neill, Brian

2013-03-01

92

In-line silica capillary tube all-silica fiber-optic Fabry-Perot interferometric sensor for detecting high intensity focused ultrasound fields.  

PubMed

Aiming at detecting high intensity focused ultrasound (HIFU) fields, this letter reports on a novel in-line silica capillary tube all-silica fiber-optic Fabry-Perot (ILSCT-ASFP) interferometric sensor fabricated by splicing a commercially available silica capillary tube to two single-mode fibers. The experimental results show that such a novel ILSCT-ASFP interferometric sensor with a cavity length of ?60.76 ?m has an excellent fringe visibility of up to ?20 dB, and the fringe visibility is still good when the cavity length extends up to ?1031.07 ?m. The measured wavelength-temperature sensitivity of 0.000858 nm/°C shows that the wavelength drift of the fabricated ILSCT-ASFP interferometric sensor towards temperature is extremely low. Meanwhile, the measurement of HIFU fields by this novel sensor is demonstrated, and the experimental results indicate that the signal-to-noise ratio of the sensing system for sensing a 0.93 MHz HIFU field with a pressure of 2.69 MPa in the focus area can reach 42.8 dB. The corresponding noise equivalent pressure is 0.0194 MPa, and the calculated acoustic sensitivity is 65.4 mV/MPa over a 2.5 MHz measurement bandwidth. PMID:22660116

Wang, D H; Wang, S J; Jia, P G

2012-06-01

93

Focused Screening and Treatment (FSAT): A PCR-Based Strategy to Detect Malaria Parasite Carriers and Contain Drug Resistant P. falciparum, Pailin, Cambodia  

PubMed Central

Recent studies have shown that Plasmodium falciparum malaria parasites in Pailin province, along the border between Thailand and Cambodia, have become resistant to artemisinin derivatives. To better define the epidemiology of P. falciparum populations and to assess the risk of the possible spread of these parasites outside Pailin, a new epidemiological tool named “Focused Screening and Treatment” (FSAT), based on active molecular detection of asymptomatic parasite carriers was introduced in 2010. Cross-sectional malariometric surveys using PCR were carried out in 20 out of 109 villages in Pailin province. Individuals detected as P. falciparum carriers were treated with atovaquone-proguanil combination plus a single dose of primaquine if the patient was non-G6PD deficient. Interviews were conducted to elicit history of cross-border travel that might contribute to the spread of artemisinin-resistant parasites. After directly observed treatment, patients were followed up and re-examined on day 7 and day 28. Among 6931 individuals screened, prevalence of P. falciparum carriers was less than 1%, of whom 96% were asymptomatic. Only 1.6% of the individuals had a travel history or plans to go outside Cambodia, with none of those tested being positive for P. falciparum. Retrospective analysis, using 2010 routine surveillance data, showed significant differences in the prevalence of asymptomatic carriers discovered by FSAT between villages classified as “high risk” and “low risk” based on malaria incidence data. All positive individuals treated and followed-up until day 28 were cured. No mutant-type allele related to atovaquone resistance was found. FSAT is a potentially useful tool to detect, treat and track clusters of asymptomatic carriers of P. falciparum along with providing valuable epidemiological information regarding cross-border movements of potential malaria parasite carriers and parasite gene flow. PMID:23049687

Hoyer, Stefan; Nguon, Sokomar; Kim, Saorin; Habib, Najibullah; Khim, Nimol; Sum, Sarorn; Christophel, Eva-Maria; Bjorge, Steven; Thomson, Andrew; Kheng, Sim; Chea, Nguon; Yok, Sovann; Top, Samphornarann; Ros, Seyha; Sophal, Uth; Thompson, Michelle M.; Mellor, Steve; Ariey, Frederic; Witkowski, Benoit; Yeang, Chhiang; Yeung, Shunmay; Duong, Socheat; Newman, Robert D.; Menard, Didier

2012-01-01

94

Performance assessment of HIFU lesion detection by Harmonic Motion Imaging for Focused Ultrasound (HMIFU): A 3D finite-element-based framework with experimental validation  

PubMed Central

Harmonic Motion Imaging for Focused Ultrasound (HMIFU) is a novel high-intensity focused ultrasound (HIFU) therapy monitoring method with feasibilities demonstrated in vitro, ex vivo and in vivo. Its principle is based on Amplitude-modulated (AM) - Harmonic Motion Imaging (HMI), an oscillatory radiation force used for imaging the tissue mechanical response during thermal ablation. In this study, a theoretical framework of HMIFU is presented, comprising a customized nonlinear wave propagation model, a finite-element (FE) analysis module, and an image-formation model. The objective of this study is to develop such a framework in order to 1) assess the fundamental performance of HMIFU in detecting HIFU lesions based on the change in tissue apparent elasticity, i.e., the increasing Young's modulus, and the HIFU lesion size with respect to the HIFU exposure time and 2) validate the simulation findings ex vivo. The same HMI and HMIFU parameters as in the experimental studies were used, i.e., 4.5-MHz HIFU frequency and 25 Hz AM frequency. For a lesion-to-background Young's modulus ratio of 3, 6, and 9, the FE and estimated HMI displacement ratios were equal to 1.83, 3.69, 5.39 and 1.65, 3.19, 4.59, respectively. In experiments, the HMI displacement followed a similar increasing trend of 1.19, 1.28, and 1.78 at 10-s, 20-s, and 30-s HIFU exposure, respectively. In addition, moderate agreement in lesion size growth was also found in both simulations (16.2, 73.1 and 334.7 mm2) and experiments (26.2, 94.2 and 206.2 mm2). Therefore, the feasibility of HMIFU for HIFU lesion detection based on the underlying tissue elasticity changes was verified through the developed theoretical framework, i.e., validation of the fundamental performance of the HMIFU system for lesion detection, localization and quantification, was demonstrated both theoretically and ex vivo. PMID:22036637

Hou, Gary Y.; Luo, Jianwen; Marquet, Fabrice; Maleke, Caroline; Vappou, Jonathan; Konofagou, Elisa E.

2014-01-01

95

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

PubMed Central

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

2014-01-01

96

Determination of total homocysteine in human serum by capillary gas chromatography with sulfur-specific detection by double focusing ICP-MS.  

PubMed

A selective and sensitive method for determination of total homocysteine (Hcy) in human serum, by gas chromatography coupled to ICP-MS(HR), has been developed. After reduction of the sample with sodium borohydride the liberated Hcy and other aminothiols, such as cysteine (Cys) and methionine (Met), were converted to their N-trifluoroacetyl (TFA)- O-isopropyl derivatives and these were injected into a gas chromatograph equipped with an HP-5 capillary column. Detection was carried out by means of a double-focusing inductively coupled plasma mass spectrometer (DF-ICP-MS) monitoring (32)S at m/Delta m (resolving power)=3000. The transfer line used to transport the analytes from the GC column to the ICP-MS had previously been developed in our laboratory. The different parameters affecting the derivatisation process were optimised, as were the instrumental operating conditions. This optimised GC-ICP-MS(HR) method was successfully applied to the determination of total homocysteine in human serum-values obtained were in agreement with data reported in the literature. Quantitative recoveries and good precision were obtained for spiked human serum, demonstrating the suitability of the method for quantitative determination of total homocysteine in serum. PMID:12844208

de la Flor St Rèmy, R R; Montes-Bayón, M; Sanz-Medel, A

2003-09-01

97

Multiple treatments with liposomal doxorubicin and ultrasound-induced disruption of blood-tumor and blood-brain barriers improve outcomes in a rat glioma model.  

PubMed

The blood-brain-barrier (BBB) prevents the transport of most anticancer agents to the central nervous system and restricts delivery to infiltrating brain tumors. The heterogeneous vascular permeability in tumor vessels, along with several other factors, creates additional barriers for drug treatment of brain tumors. Focused ultrasound (FUS), when combined with circulating microbubbles, is an emerging noninvasive method to temporarily permeabilize the BBB and the "blood-tumor barrier". Here, we tested the impact of three weekly sessions of FUS and liposomal doxorubicin (DOX) in 9L rat glioma tumors. Animals that received FUS+DOX (N=8) had a median survival time that was increased significantly (P<0.001) compared to animals who received DOX only (N=6), FUS only (N=8), or no treatment (N=7). Median survival for animals that received FUS+DOX was increased by 100% relative to untreated controls, whereas animals who received DOX alone had only a 16% improvement. Animals who received only FUS showed no improvement. No tumor cells were found in histology in 4/8 animals in the FUS+DOX group, and in two animals, only a few tumor cells were detected. Adverse events in the treatment group included skin toxicity, impaired activity, damage to surrounding brain tissue, and tissue loss at the tumor site. In one animal, intratumoral hemorrhage was observed. These events are largely consistent with known side effects of doxorubicin and with an extensive tumor burden. Overall this work demonstrates that multiple sessions using this FUS technique to enhance the delivery of liposomal doxorubicin have a pronounced therapeutic effect in this rat glioma model. PMID:23603615

Aryal, Muna; Vykhodtseva, Natalia; Zhang, Yong-Zhi; Park, Juyoung; McDannold, Nathan

2013-07-10

98

An enhancer variant of Moloney murine leukemia virus defective in leukemogenesis does not generate detectable mink cell focus-inducing virus in vivo.  

PubMed Central

Moloney murine leukemia virus (Mo-MuLV) induces T-cell lymphoma when inoculated into neonatal mice. This is a multistep process. Early events observed in infected mice include generalized hematopoietic hyperplasia in the spleen and appearance of mink cell focus-inducing (MCF) recombinants; end-stage tumors are characterized by insertional proviral activation of protooncogenes. We previously showed that an Mo-MuLV enhancer variant, Mo+PyF101 Mo-MuLV, has greatly reduced leukemogenicity and is deficient in induction of preleukemic hyperplasia. In this report, we have examined Mo+PyF101 Mo-MuLV-inoculated mice for the presence of MCF recombinants. In contrast to wild-type Mo-MuLV-inoculated mice, Mo+PyF101 Mo-MuLV-inoculated mice did not generate detectable MCF recombinants. This failure was at least partly due to an inability of the MCF virus to propagate in vivo, since a molecularly cloned infectious Mo+PyF101 MCF virus did not replicate, even when inoculated as a Mo+PyF101 Mo-MuLV pseudotype. These results show that the leukemogenic defect of Mo+PyF101 Mo-MuLV is associated with its inability to generate MCF recombinants capable of replication in vivo. This, in turn, is consistent with the view that MCF recombinants play a significant role in Mo-MuLV-induced disease and, in particular, may play a role early in the disease process. Images PMID:2006167

Brightman, B K; Rein, A; Trepp, D J; Fan, H

1991-01-01

99

Tsunami focusing  

NASA Astrophysics Data System (ADS)

Tsunamis are long waves generated by impulsive disturbances of the seafloor or coastal topography caused by earthquakes, submarine/subaerial mass failures. They evolve substantially through three dimensional - 2 spatial+1 temporal - spreading as the initial surface deformation propagates. This is referred to as its directivity and focusing. A directivity function was first defined by Ben-Menahem (1961, Bull. Seismol. Soc. Am. 51, 401-435) using the source length and the rupture velocity. Okal (2003, Pure Appl. Geophys. 160, 2189-2221) discussed the details of the analysis of Ben-Menahem (1961) and demonstrated the distinct difference between the directivity patterns of landslide and earthquake generated tsunamis. Marchuk and Titov (1989, Proc. IUGG/IOC International Tsunami Symposium, July 31 - August 3, 1989, Novosibirsk, USSR. p.11-17) described the process of tsunami focusing for a rectangular initial deformation combining positive and negative surface displacements. They showed the existence of a focusing point where abnormal tsunami wave height can be registered. Here, first, we describe and quantify numerically tsunami focusing processes for a combined positive and negative - N-wave type - strip source representing the 17 July 1998 Papua New Guinea and 17 July 2006 Java events. Specifically, considering field observations and tsunami focusing, we propose a source mechanism for the 17 July 2006 Java event. Then, we introduce a new analytical solution for a strip source propagating over a flat bottom using the linear shallow-water wave equation. The analytical solution of Carrier and Yeh (2005, Computer Modeling In Engineering & Sciences, 10(2), 113-121) appears to have two drawbacks. One, the solution involves singular complete elliptic integral of the first kind which results in a self-similar approximate solution for the far-field at large times. Two, only the propagation of Gaussian shaped finite-crest wave profiles can be modeled. Our solution is not only exact but also more general and allows the use of realistic initial waveform such as N-waves defined by Tadepalli and Synolakis (1994, Proc. R. Soc. Lond. A 445, 99-112). We explore parametric dependence of the focusing height and distance on the initial wave parameters through the analytical solution.

Spillane, M. C.; Titov, V. V.; Moore, C. W.; Aydin, B.; Kanoglu, U.; Synolakis, C. E.

2010-12-01

100

Electrophoretic Focusing  

NASA Technical Reports Server (NTRS)

Electrophoretic focusing is a new method of continuous flow electrophoresis that introduces precision flow control to achieve high resolution separations. The electric field is applied perpendicular to an incoming sample lamina and buffer but also perpendicular to the broad faces of the thin rectangular chamber. A uniform fluid cross-flow then enters and exits the separation chamber through the same broad faces which are porous. A balance is achieved by adjusting either the electric field or the cross-flow so the desired sample fraction with its specific migration velocity encounters an opposing flow of the same velocity. Applying an electric field transverse to the incoming sample lamina and opposing this field with a carefully configured buffer flow, a sample constituent can be selected and focused into a narrow stream for subsequent analysis. Monotonically changing either electric field or buffer cross-flow will yield a scan of all constituents of the sample. Stopping the scan increases the collection time for minor constituents to improve their analysis. Using the high voltage gradients and/or cross-flow to rapidly deflect extraneous sample through the porous screens and into either of the side (purge) chambers, the selected sample is focused in the center plane of the separation chamber and collected without contact or interaction with the separation chamber walls. Results will be presented on the separation of a range of materials including dyes, proteins, and monodisperse polystyrene latexes. Sources of sample dispersion inherent in other electrokinetic techniques will be shown to be negligible for a variety of sample concentrations, buffer properties and operating conditions.

Snyder, Robert S.

2001-01-01

101

Scanning temperature gradient focusing.  

PubMed

Temperature gradient focusing (TGF) is a recently developed technique for the simultaneous concentration and electrophoretic separation of ionic analytes in microfluidic channels. One drawback to TGF as it has previously been described is the limited peak capacity; only a small number of analyte peaks (approximately 2-3) can be simultaneously focused and separated. In this paper, we report on a variation of the TGF method whereby the bulk flow rate is varied over time so that a large number of analytes can be sequentially focused, moved past a fixed detection point, and flushed to waste. In addition to improved peak capacity, the detection limits of the scanning TGF method can be adjusted on-the-fly, as needed for different samples. Finally, scanning TGF provides a technique by which high-resolution, high-peak-capacity electrophoretic separations can be performed in simple, straight, and short microfluidic channels. PMID:17037919

Hoebel, Stacey J; Balss, Karin M; Jones, Barbara J; Malliaris, Constantin D; Munson, Matthew S; Vreeland, Wyatt N; Ross, David

2006-10-15

102

Noninvasive and Transient Blood-Brain Barrier Opening in the Hippocampus of Alzheimer's Double Transgenic Mice Using Focused Ultrasound  

PubMed Central

The spatio-temporal nature of focused ultrasound-induced blood-brain barrier (BBB) opening as a brain drug delivery method was investigated in Alzheimer's disease model mice. The left hippocampus of transgenic (APP/PS1, n = 3) and nontransgenic (n = 3) mice was sonicated (frequency: 1.525 MHz, peak-negative pressure: 600 kPa, pulse length: 20 ms, duty cycle: 20%, duration: 1 min) in vivo, through their intact skin and skull, after intravenous injection of microbubbles (SonoVue®; 25 ?l). Sequential, high-field MR images (9.4 Tesla) were acquired before and after injection of gadolinium (Omniscan™; 0.75 ml, molecular weight: 573.7 Da) on two separate days for each mouse. Gadolinium deposits through the ultrasound-induced BBB opening in the left hippocampus revealed significant contrast-enhancement in the MRI. On the following day, MRI revealed significant BBB closure within the same region. However, the BBB opening extent and BBB closing timeline varied in different regions within the same sonicated location. This indicates that opening and closing were dependent on the brain region targeted. No significant difference in BBB opening or closing behaviors was observed between the APP/PS1 and the nontransgenic mice. In conclusion, a BBB-impermeable molecule was noninvasively, transiently and reproducibly delivered to the hippocampus of Alzheimer's APP/PS1 mice. PMID:19149463

Choi, James J.; Wang, Shougang; Brown, Truman R.; Small, Scott A.; Duff, Karen E. K.; Konofagou, Elisa E.

2009-01-01

103

Theoretical and experimental study on temperature elevation behind ribs caused by weakly focused ultrasound  

PubMed Central

Temperature distribution in tissues behind ribs produced by weakly focused ultrasound had been calculated using Pennes bioheat equation, and the validity of the theoretical model was experimentally confirmed in vitro using porcine live. We found that the position of the maximum temperature in tissue is strongly influenced by the distance between the transducer and ribs, while the gap between ribs is the determining factor for the maximum achievable temperature. Within the focal length, when the distance between the transducer and ribs increases, the maximum temperature increases and its position shifts away from the transducer. The rib width has little effect on the position of the maximum temperature but affects the achievable peak temperature. Our results provide useful information for treating liver cancers using ultrasound induced hyperthermia. PMID:20800959

Liu, Xiaozhou; Yin, Chang; Gong, Xiufen; Cao, Wenwu

2010-01-01

104

Evaluation of in vitro methods for detecting the effects of various chemicals on the human progesterone receptor, with a focus on pyrethroid insecticides  

Microsoft Academic Search

The progesterone receptor (PR) is associated with physiological events such as implantation and the maintenance of pregnancy. Recently, it has become a social concern that chemicals may exert agonistic or antagonistic effects on hormone receptors. Therefore, we examined the effects of various chemicals on the human PR, with a focus on pyrethroid insecticides, using three in vitro methods. Eight pyrethroid

Kayo Sumida; Koichi Saito; Norihisa Ooe; Naohiko Isobe; Hideo Kaneko; Iwao Nakatsuka

2001-01-01

105

Genetic and Ecological Correlates of Intraspecific Variation in Pitviper Venom Composition Detected Using Matrix-Assisted Laser Desorption Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) and Isoelectric Focusing  

Microsoft Academic Search

The ability to detect biochemical diversity in animal venoms has wide-ranging implications for a diverse array of scientific disciplines. Matrix-assisted laser desorption time-of-flight mass spectrometry (and, for comparative purposes, isoelectric focusing) were used to characterize venoms from a geographically diverse sample of Trimeresurus stejnegeri (n 2 isoforms (PLA2) and in whole venom profiles. Geographic variation in venom was primarily between

Simon Creer; Anita Malhotra; Roger S. Thorpe; Reto S. Stöcklin; Philippe S. Favreau; Wen S. Hao Chou

2003-01-01

106

Evaluation of in vitro methods for detecting the effects of various chemicals on the human progesterone receptor, with a focus on pyrethroid insecticides.  

PubMed

The progesterone receptor (PR) is associated with physiological events such as implantation and the maintenance of pregnancy. Recently, it has become a social concern that chemicals may exert agonistic or antagonistic effects on hormone receptors. Therefore, we examined the effects of various chemicals on the human PR, with a focus on pyrethroid insecticides, using three in vitro methods. Eight pyrethroid insecticides (fenvalerate, d-allethrin, d-phenothrin, prallethrin, empenthrin, permethrin, cypermethrin and imiprothrin), examples of environmental pollutants and positive control chemicals were subjected to a reporter gene assay (luciferase assay) using human breast cancer T-47D cells, a two-hybrid assay and a binding assay using the same whole cells or receptors (cell-free). In none of these did the eight pyrethroid insecticides show any binding to the PR, agonistic or antagonistic effects. PMID:11137321

Sumida, K; Saito, K; Ooe, N; Isobe, N; Kaneko, H; Nakatsuka, I

2001-01-01

107

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

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

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

2013-01-01

108

Ultrasound induces aging in granular materials.  

PubMed

Aging and rejuvenation have been identified as the general mechanisms that rule the time evolution of granular materials subjected to some external confinement pressure. In creep experiments performed in a triaxial configuration, we obtained evidence that relatively high intensity ultrasound waves propagating through the material induce both weakening and significant plasticity. In the framework of glassy materials, it is shown that the effect of ultrasound can be simply accounted for by a general variable, the fluidity, whose dynamics are described by an effective aging parameter that strongly decreases with sound amplitude and vanishes at the yield stress limit. The response from step perturbations in ultrasound intensity provided a method to assess the effective-viscosity jumps which are direct evidence of acoustic fluidization. PMID:23102371

Espíndola, David; Galaz, Belfor; Melo, Francisco

2012-10-12

109

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

PubMed Central

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

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

2008-01-01

110

Focus Sensitive Coordination  

E-print Network

This thesis investigates the role of the Focus Sensitive Operators (FSOs) even and also when found inside of a coordination. Coordinations of this form are called Focus Sensitive Coordinations (FSC) and include or even, ...

Hulsey, Sarah McNearney

2008-01-01

111

Focus Training Manual; A Focus Dissemination Project.  

ERIC Educational Resources Information Center

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…

Human Resource Associates, Inc., Hastings, Minn.

112

Kinematic of focusing regions  

NASA Astrophysics Data System (ADS)

We describe the interaction between focusing regions and analyze the resulting physical features. The study is supported by the fact that focusing regions exhibit particle-like behavior and the interaction among these presents features similar to inelastic collision. When focusing regions are generated in a medium with random refractive index, the irradiance distribution along the focusing regions changes according to the diffusion process and the collision between them generates vortex-like effects. This study was implemented by solving the irradiance transport equation. Experimental results are in good agreement with the theoretical model performed.

Martínez-Niconoff, G.; De los Santos G, S. I.; Silva-Barranco, J.; Martínez-Martínez, J. A.; Martínez-Vara, P.; Ramírez-San-Juan, J. C.

2014-08-01

113

Focus, 2000-2001.  

ERIC Educational Resources Information Center

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…

Focus, 2001

2001-01-01

114

Robust focus ranging  

Microsoft Academic Search

Depth maps obtained from focus ranging can have numerous errors and distortions due to edge bleeding, feature shifts, image noise, and field curvature. An improved algorithm that examines an initial high depth-of-field image of the scene to identify regions susceptible to edge bleeding and image noise is given. Focus evaluation windows are adapted to local image content and optimize the

Hari N. Nair; Charles V. Stewart

1992-01-01

115

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.

116

A miniature focus sensor  

Microsoft Academic Search

The ability to rapidly measure the focus of images acquired by optical systems is important in many applications. Itek Optical Systems, building on its extensive wavefront sensing and adaptive optics capability, has developed an electro-optic focus sensor directly mounted to a Nikon Camera. The sensor operates by measuring the relative position of the image formed by two halves of the

A. J. MacGovern

1984-01-01

117

Emotionally Focused Couple Therapy  

Microsoft Academic Search

Working with couples who are both survivors of emotional abuse and are currently in an emotionally abusive relationship can be particularly challenging for the clinician. This article focuses on Emotionally Focused Couple Therapy as a recommended practice approach for clients who are caught in emotionally abusive patterns with one another. The article reviews relevant literature on this approach and illustrates

Nancy L. Beckerman; Michele Sarracco

2002-01-01

118

Flat focusing mirror.  

PubMed

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

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

2014-01-01

119

Final focus test beam  

SciTech Connect

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.

Not Available

1991-03-01

120

Current focusing and steering  

PubMed Central

Current steering and current focusing are stimulation techniques designed to increase the number of distinct perceptual channels available to cochlear implant (CI) users by adjusting currents applied simultaneously to multiple CI electrodes. Previous studies exploring current steering and current focusing stimulation strategies are reviewed, including results of research using computational models, animal neurophysiology, and human psychophysics. Preliminary results of additional neurophysiological and human psychophysical studies are presented that demonstrate the success of current steering strategies in stimulating auditory nerve regions lying between physical CI electrodes, as well as current focusing strategies that excite regions narrower than those stimulated using monopolar configurations. These results are interpreted in the context of perception and speech reception by CI users. Disparities between results of physiological and psychophysical studies are discussed. The differences in stimulation used for physiological and psychophysical studies are hypothesized to contribute to these disparities. Finally, application of current steering and focusing strategies to other types of auditory prostheses is also discussed. PMID:18501539

Bonham, Ben H.; Litvak, Leonid M.

2008-01-01

121

STRATEGIC FOCUS: Sustainable Systems  

E-print Network

to apply sustain- ability principles to building and design, transportation and other fields, to green1010 STRATEGIC FOCUS: Sustainable Systems Biology doctoral student Tanya Lubansky uses quan and quantitative ecologists. Sustainable Systems in NJIT's Educational Programs Educational offerings

122

Inertial focusing in microfluidics.  

PubMed

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

Martel, Joseph M; Toner, Mehmet

2014-07-11

123

Focusing corner cube  

DOEpatents

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.

Monjes, J.A.

1985-09-12

124

Patient-focused care.  

PubMed

The trend away from a departmental focus and toward "patient-focused" care in hospitals is described; advantages of and barriers to such a change and its effects on pharmacy are discussed. Patient-focused care is characterized by decentralization of services, cross-training of personnel from different departments to provide basic care, interdisciplinary collaboration, various degrees of organizational restructuring, use of "clinical pathways"--recommended components of care for patients with a particular diagnosis, simplification and redesign of work to eliminate steps and save time (e.g., providing care according to predetermined protocols and charting only exceptions to the protocol), and increased involvement of patients in their own care. Its objectives are to use nonclinical and clinical staff more effectively and to improve patients' perceptions of the quality of care and staff members' job satisfaction. It is unrealistic to expect quick reductions in hospital costs through patient-focused care, and workers will worry about job security if an institution overemphasizes this aspect. A 1993 survey of 311 hospitals found that almost half had or planned to have patient-focused care projects. Adoption of patient-focused care projects may be slowed by workers' fear of new responsibilities and new reporting relationships. However, not all patient-focused care models involve radical organizational changes, and reorganizations can be such that pharmacy staff members are still connected to the pharmacy department even if they are supervised by a nonpharmacist. In some institutions patient-focused care projects have given pharmacy its first opportunity for decentralization.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8266955

Vogel, D P

1993-11-01

125

Plutonium focus area  

SciTech Connect

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.

NONE

1996-08-01

126

New molecular identifiers for Simulium limbatum and Simulium incrustatum s.l. and the detection of genetic substructure with potential implications for onchocerciasis epidemiology in the Amazonia focus of Brazil.  

PubMed

The Amazonia onchocerciasis focus of southern Venezuela and northern Brazil is the larger of the two remaining Latin American onchocerciasis foci where disease transmission still occurs and is often regarded as the most challenging of all the Latin American foci to eliminate onchocerciasis. The site is home to a population of over 20,000 semi-nomadic, hunter-gatherer Yanomami people and is made-up of a mosaic of rainforest and savannah ecologies, which are influenced by the area's undulating terrain and rich geological diversity. At least six blackfly vectors have been implicated in onchocerciasis transmission in this focus; however, because of the difficulty in their routine identification the relative importance of each has been obscured. Simulium limbatum and Simulium incrustatum s.l. have both been recorded as vectors in the Amazonia focus, but they are difficult to discriminate morphologically and thus the ecological range of these species, and indeed the presence of S. limbatum in the Amazonia focus at all, have remained controversial. In the work described here, we report 15 S. incrustatum s.l. CO1 sequences and 27 S. limbatum sequences obtained from field-caught adult female blackflies collected from forest and savannah localities, inside and just outside the Amazonia focus. Phylogenetic analysis with the sequences generated in this study, showed that both the S. limbatum and the S. incrustatum s.l. CO1 sequences obtained (even from specimens living in sympatry) all fell into discrete species-specific bootstrap-supported monophyletic groups and thus confirmed the utility of the CO1 gene for identifying both these species inside the Amazonia focus. As the S. limbatum-exclusive cluster included CO1 sequences obtained from forest-caught and morphologically identified specimens these results provide the clearest evidence yet of the presence of S. limbatum inside the Amazonia focus. The question, however, of whether S. limbatum is actually a vector in the focus still remains unanswered as the data presented here also suggest that S. limbatum found in the savannahs adjacent to, but outside the Amazonia focus (and which represent the only S. limbatum population to be unambiguously incriminated as a host of Onchocerca volvulus), are genetically distinct from those living inside the focus. These findings highlight the need for a clearer picture of the vector taxonomy inside the Amazonia onchocerciasis focus. PMID:23545131

Conceição, Priscila A; Crainey, James L; Almeida, Tatiana P; Shelley, Anthony J; Luz, Sergio L B

2013-08-01

127

Decontamination & decommissioning focus area  

SciTech Connect

In January 1994, the US Department of Energy Office of Environmental Management (DOE EM) formally introduced its new approach to managing DOE`s environmental research and technology development activities. The goal of the new approach is to conduct research and development in critical areas of interest to DOE, utilizing the best talent in the Department and in the national science community. To facilitate this solutions-oriented approach, the Office of Science and Technology (EM-50, formerly the Office of Technology Development) formed five Focus AReas to stimulate the required basic research, development, and demonstration efforts to seek new, innovative cleanup methods. In February 1995, EM-50 selected the DOE Morgantown Energy Technology Center (METC) to lead implementation of one of these Focus Areas: the Decontamination and Decommissioning (D & D) Focus Area.

NONE

1996-08-01

128

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.

129

Sagittal focusing Laue monochromator  

SciTech Connect

An x-ray focusing device generally includes a slide pivotable about a pivot point defined at a forward end thereof, a rail unit fixed with respect to the pivotable slide, a forward crystal for focusing x-rays disposed at the forward end of the pivotable slide and a rearward crystal for focusing x-rays movably coupled to the pivotable slide and the fixed rail unit at a distance rearward from the forward crystal. The forward and rearward crystals define reciprocal angles of incidence with respect to the pivot point, wherein pivoting of the slide about the pivot point changes the incidence angles of the forward and rearward crystals while simultaneously changing the distance between the forward and rearward crystals.

Zhong; Zhong (Stony Brook, NY), Hanson; Jonathan (Wading River, NY), Hastings; Jerome (Stanford, CA), Kao; Chi-Chang (Setauket, NY), Lenhard; Anthony (Medford, NY), Siddons; David Peter (Cutchogue, NY), Zhong; Hui (Coram, NY)

2009-03-24

130

A miniature focus sensor  

NASA Astrophysics Data System (ADS)

The ability to rapidly measure the focus of images acquired by optical systems is important in many applications. Itek Optical Systems, building on its extensive wavefront sensing and adaptive optics capability, has developed an electro-optic focus sensor directly mounted to a Nikon Camera. The sensor operates by measuring the relative position of the image formed by two halves of the optical aperture. The measurement is performed using a scanning technique and a processing algorithm implemented by digital electronics. Details of the sensor design with results of its operation are presented.

MacGovern, A. J.

1984-01-01

131

Focus on Rashomon.  

ERIC Educational Resources Information Center

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,…

Richie, Donald S., Ed.

132

Bilingual Education. IDRA Focus.  

ERIC Educational Resources Information Center

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…

IDRA Newsletter, 1998

1998-01-01

133

Public Engagement. IDRA Focus.  

ERIC Educational Resources Information Center

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…

IDRA Newsletter, 1996

1996-01-01

134

Education Policy. IDRA Focus.  

ERIC Educational Resources Information Center

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…

IDRA Newsletter, 1998

1998-01-01

135

Focus on Basics, 1997.  

ERIC Educational Resources Information Center

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…

Focus on Basics, 1997

1997-01-01

136

Becoming Solution-Focused  

Microsoft Academic Search

This preliminary paper addresses how therapists, students, and professionals go about the business of learning to accept the concepts and philosophy of becoming brief, solution-focused therapists. What is it that “clicks” for them to make that paradigmatic shift? This paper is a beginning exploration to this overarching question as we research therapists' experiences in moving from one model of therapy

Lee Shuts; Kaisha A. Thomas

2005-01-01

137

Utilization-focused Evaluation  

Microsoft Academic Search

The results of any particular effort cannot be guaranteed. Each evaluation being a blend of unique ingredients, no standardized recipe can assure the outcome. We have only principles, premises, and utilization-focused processes to guide us, and we have much yet to learn. But, the potential benefits merit the efforts and risks involved. At stake is improving the effectiveness of programs

Michael Patton

138

Focusing on the Invisible  

ERIC Educational Resources Information Center

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…

Haley, Tim R.

2008-01-01

139

Focusing in Plan Recognition  

Microsoft Academic Search

A plan recognition architecture is presented which exploits application-specific heuristic knowledge to quickly focus the search to a small set of plausible plan interpretations from the very large set of possible interpretations. The heuristic knowledge is formalized for use in a truth maintenance system where interpretation assumptions and their heuristic justifications are recorded. By formalizing this knowledge, the system is

Norman Carver; Victor R. Lesser; Daniel L. Mccue

1984-01-01

140

Focus: International Economics.  

ERIC Educational Resources Information Center

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…

Lynch, Gerald J.; Watts, Michael W.; Wentworth, Donald R.

141

Children in Focus  

Microsoft Academic Search

Presents new findings in the field of nutrition research from the conference, Children in Focus, organized by the National Dairy Council. Expert speakers address vital issues on how children feel and learn about food and how to persuade them to improve their diets.

Dilys Wells

1994-01-01

142

Focus Article Nuclear winter  

E-print Network

Focus Article Nuclear winter Alan Robock Nuclear winter is the term for a theory describing the climatic effects of nuclear war. Smoke from the fires started by nuclear weapons, especially the black of these indirect effects. Nuclear proliferation is now expanding the threat. A nuclear war between India

Robock, Alan

143

Homework. Focus On  

ERIC Educational Resources Information Center

Homework has been an integral part of the educational system for over 100 years. What likely began as simple memorization tasks has evolved into complex projects and sparked an increasingly heated debate over the purpose and value of homework assignments. This "Focus On" examines the purpose of homework, how to create homework that has value,…

Rahal, Michelle Layer

2010-01-01

144

Focus: Economic Systems.  

ERIC Educational Resources Information Center

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…

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

145

Policy Update. IDRA Focus.  

ERIC Educational Resources Information Center

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;…

IDRA Newsletter, 1995

1995-01-01

146

Neocortical focus: experimental view.  

PubMed

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

Timofeev, Igor; Chauvette, Sylvain; Soltani, Sara

2014-01-01

147

Focus on Understanding.  

ERIC Educational Resources Information Center

Discussion of the tension between students and teachers regarding understanding in information tasks focuses on the role the teacher-librarian can take to help boost student achievement and to help teachers create information tasks. Topics include curriculum goals; integrating information literacy skills; facets of understanding; and the…

Koechlin, Carol; Zwaan, Sandi

2002-01-01

148

Equity. IDRA Focus.  

ERIC Educational Resources Information Center

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…

IDRA Newsletter, 1998

1998-01-01

149

Enhanced Tumor Uptake and Penetration of Virotherapy Using Polymer Stealthing and Focused Ultrasound  

PubMed Central

Background Oncolytic viruses are among the most powerful and selective cancer therapeutics under development and are showing robust activity in clinical trials, particularly when administered directly into tumor nodules. However, their intravenous administration to treat metastatic disease has been stymied by unfavorable pharmacokinetics and inefficient accumulation in and penetration through tumors. Methods Adenovirus (Ad) was “stealthed” with a new N-(2-hydroxypropyl)methacrylamide polymer, and circulation kinetics were characterized in Balb/C SCID mice (n = 8 per group) bearing human ZR-75-1 xenograft tumors. Then, to noninvasively increase extravasation of the circulating polymer-coated Ad into the tumor, it was coinjected with gas microbubbles and the tumor was exposed to 0.5 MHz focused ultrasound at peak rarefactional pressure of 1.2MPa. These ultrasound exposure conditions were designed to trigger inertial cavitation, an acoustic phenomenon that produces shock waves and can be remotely monitored in real-time. Groups were compared with Student t test or one-way analysis of variance with Tukey correction where groups were greater than two. All statistical tests were two-sided. Results Polymer-coating of Ad reduced hepatic sequestration, infection (>8000-fold; P < .001), and toxicity and improved circulation half-life (>50-fold; P = .001). Combination of polymer-coated Ad, gas bubbles, and focused ultrasound enhanced tumor infection >30-fold; (4×106 photons/sec/cm2; standard deviation = 3×106 with ultrasound vs 1.3×105; standard deviation = 1×105 without ultrasound; P = .03) and penetration, enabling kill of cells more than 100 microns from the nearest blood vessel. This led to substantial and statistically significant retardation of tumor growth and increased survival. Conclusions Combining drug stealthing and ultrasound-induced cavitation may ultimately enhance the efficacy of a range of powerful therapeutics, thereby improving the treatment of metastatic cancer. PMID:24168971

2013-01-01

150

Focus on quantum efficiency  

NASA Astrophysics Data System (ADS)

Technologies which convert light into energy, and vice versa, rely on complex, microscopic transport processes in the condensed phase, which obey the laws of quantum mechanics, but hitherto lack systematic analysis and modeling. Given our much improved understanding of multicomponent, disordered, highly structured, open quantum systems, this ‘focus on’ collection collects cutting-edge research on theoretical and experimental aspects of quantum transport in truly complex systems as defined, e.g., by the macromolecular functional complexes at the heart of photosynthesis, by organic quantum wires, or even photovoltaic devices. To what extent microscopic quantum coherence effects can (be made to) impact on macroscopic transport behavior is an equally challenging and controversial question, and this ‘focus on’ collection provides a setting for the present state of affairs, as well as for the ‘quantum opportunities’ on the horizon.

Buchleitner, Andreas; Burghardt, Irene; Cheng, Yuan-Chung; Scholes, Gregory D.; Schwarz, Ulrich T.; Weber-Bargioni, Alexander; Wellens, Thomas

2014-10-01

151

Fedgazette Focus: Hog Markets  

NSDL National Science Digital Library

This January 1999 issue of Fedgazette from the Federal Reserve Bank of Minneapolis focuses on the recent downward spiral of hog prices to historic lows in the Midwest. Over ten articles explore pork prices, agricultural finance, and whether or not "agriculture is in crisis" across the nation. Additional links to maps, charts and economic statistics offer other educational resources on the issue from the Ninth Federal Reserve District site.

1999-01-01

152

Globalization in Focus  

NSDL National Science Digital Library

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.

2001-01-01

153

Subsurface contaminants focus area  

SciTech Connect

The US Department of Enregy (DOE) Subsurface Contaminants Focus Area is developing technologies to address environmental problems associated with hazardous and radioactive contaminants in soil and groundwater that exist throughout the DOE complex, including radionuclides, heavy metals; and dense non-aqueous phase liquids (DNAPLs). More than 5,700 known DOE groundwater plumes have contaminated over 600 billion gallons of water and 200 million cubic meters of soil. Migration of these plumes threatens local and regional water sources, and in some cases has already adversely impacted off-site rsources. In addition, the Subsurface Contaminants Focus Area is responsible for supplying technologies for the remediation of numerous landfills at DOE facilities. These landfills are estimated to contain over 3 million cubic meters of radioactive and hazardous buried Technology developed within this specialty area will provide efective methods to contain contaminant plumes and new or alternative technologies for development of in situ technologies to minimize waste disposal costs and potential worker exposure by treating plumes in place. While addressing contaminant plumes emanating from DOE landfills, the Subsurface Contaminants Focus Area is also working to develop new or alternative technologies for the in situ stabilization, and nonintrusive characterization of these disposal sites.

NONE

1996-08-01

154

Modeling localized delivery of Doxorubicin to the brain following focused ultrasound enhanced blood-brain barrier permeability  

NASA Astrophysics Data System (ADS)

Doxorubicin (Dox) is a well-established chemotherapeutic agent, however it has limited efficacy in treating brain malignancies due to the presence of the blood-brain barrier (BBB). Recent preclinical studies have demonstrated that focused ultrasound induced BBB disruption (BBBD) enables efficient delivery of Dox to the brain. For future treatment planning of BBBD-based drug delivery, it is crucial to establish a mathematical framework to predict the effect of transient BBB permeability enhancement on the spatiotemporal distribution of Dox at the targeted area. The constructed model considers Dox concentrations within three compartments (plasma, extracellular, intracellular) that are governed by various transport processes (e.g. diffusion in interstitial space, exchange across vessel wall, clearance by cerebral spinal fluid, uptake by brain cells). By examining several clinical treatment aspects (e.g. sonication scheme, permeability enhancement, injection mode), our simulation results support the experimental findings of optimal interval delay between two consecutive sonications and therapeutically-sufficient intracellular concentration with respect to transfer constant Ktrans range of 0.01–0.03 min−1. Finally, the model suggests that infusion over a short duration (20–60 min) should be employed along with single-sonication or multiple-sonication at 10 min interval to ensure maximum delivery to the intracellular compartment while attaining minimal cardiotoxicity via suppressing peak plasma concentration.

Nhan, Tam; Burgess, Alison; Lilge, Lothar; Hynynen, Kullervo

2014-10-01

155

Modeling localized delivery of Doxorubicin to the brain following focused ultrasound enhanced blood-brain barrier permeability.  

PubMed

Doxorubicin (Dox) is a well-established chemotherapeutic agent, however it has limited efficacy in treating brain malignancies due to the presence of the blood-brain barrier (BBB). Recent preclinical studies have demonstrated that focused ultrasound induced BBB disruption (BBBD) enables efficient delivery of Dox to the brain. For future treatment planning of BBBD-based drug delivery, it is crucial to establish a mathematical framework to predict the effect of transient BBB permeability enhancement on the spatiotemporal distribution of Dox at the targeted area. The constructed model considers Dox concentrations within three compartments (plasma, extracellular, intracellular) that are governed by various transport processes (e.g. diffusion in interstitial space, exchange across vessel wall, clearance by cerebral spinal fluid, uptake by brain cells). By examining several clinical treatment aspects (e.g. sonication scheme, permeability enhancement, injection mode), our simulation results support the experimental findings of optimal interval delay between two consecutive sonications and therapeutically-sufficient intracellular concentration with respect to transfer constant Ktrans range of 0.01-0.03?min(-1). Finally, the model suggests that infusion over a short duration (20-60?min) should be employed along with single-sonication or multiple-sonication at 10?min interval to ensure maximum delivery to the intracellular compartment while attaining minimal cardiotoxicity via suppressing peak plasma concentration. PMID:25230100

Nhan, Tam; Burgess, Alison; Lilge, Lothar; Hynynen, Kullervo

2014-10-21

156

Evaluation of focus measures in multi-focus image fusion  

Microsoft Academic Search

Several focus measures were studied in this paper as the measures of image clarity, in the field of multi-focus image fusion. All these focus measures are defined in the spatial domain and can be implemented in real-time fusion systems with fast response and robustness. This paper proposed a method to assess focus measures according to focus measures’ capability of distinguishing

Wei Huang; Zhongliang Jing

2007-01-01

157

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.

1999-01-01

158

Flux focusing eddy current probe  

NASA Technical Reports Server (NTRS)

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.

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

159

Isoelectric focusing in space  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

160

|Research Focus Seeing patterns in the noise  

E-print Network

to statistical sampling error) (Fig. 2b). Conversely, if these response-triggered distributions do not match|Research Focus Seeing patterns in the noise Eero P. Simoncelli Howard Hughes Medical Institute responsible for the detection and identification of a specific visual target. What is it that allows us

Simoncelli, Eero

161

Focus on granular segregation  

NASA Astrophysics Data System (ADS)

Ordinary fluids mix themselves through thermal motions, or can be even more efficiently mixed by stirring. In contrast, granular materials such as sand often unmix when they are stirred, shaken or sheared. This granular segregation is both a practical means to separate materials in industry, and a persistent challenge to uniformly mixing them. While segregation phenomena are ubiquitous, a large number of different mechanisms have been identified and the underlying physics remains the subject of much inquiry. Particle size, shape, density and even surface roughness can play significant roles. The aim of this focus issue is to provide a snapshot of the current state of the science, covering a wide range of packing densities and driving mechanisms, from thermal-like dilute systems to dense flows.

Daniels, Karen E.; Schröter, Matthias

2013-03-01

162

In Focus: The Tree  

NSDL National Science Digital Library

In Focus: The Tree, is a Getty Museum exhibition of 41 images inspired by trees. On the exhibition's website visitors can see five images of trees, from Myoung Ho Lee, William Henry Fox Talbot, Darius Kinsey, Rhea Garen, and Simryn Gill, most accompanied by audio of curators or the artists discussing their work. Curator FranÃÂçoise Reynaud explains how early photographer Talbot may have created his 1842 salt print showing a bare oak tree in winter; living artist Rheas Garen discusses her picture "Treehouse", which shows a backyard where a tree dwarfs the house, taken with a large format camera in 1993. The associated book, The Tree in Photographs, compiled by Reynaud, includes eighty-one images selected from the Museum's permanent collection.

163

Focusing on customer service.  

PubMed

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

1996-01-01

164

Comparative analysis of different focusators focusing into a segment  

Microsoft Academic Search

Computer generated diffractive optical elements, known as ‘focusators’, provide very complicated focal intensity distributions. The manufacture of such elements is very expensive and must be preceded by computer simulation of their performance. A computational experiment, with laser beam focusators focusing into a segment, is described in this paper. Estimations of power efficiency and focal line quality for various focusator phase

L. L. Doskolovich; N. L. Kazanskiy; V. A. Soifer

1995-01-01

165

COMPRENDO: Focus and Approach  

PubMed Central

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

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; Klingmuller, Dietrich; Kloas, Werner; Kusk, Kresten Ole; Levada, Ramon; Lo, Susan; Lutz, Ilka; Oehlmann, Jorg; Oredsson, Stina; Porte, Cinta; Rand-Weaver, Marian; Sakkas, Vasilis; Sugni, Michela; Tyler, Charles; van Aerle, Ronny; van Ballegoy, Christoph; Wollenberger, Leah

2006-01-01

166

Focus Point Supersymmetry Redux  

E-print Network

Recent results from Higgs boson and supersymmetry searches at the Large Hadron Collider provide strong new motivations for supersymmetric theories with heavy superpartners. We reconsider focus point supersymmetry (FP SUSY), in which all squarks and sleptons may have multi-TeV masses without introducing fine-tuning in the weak scale with respect to variations in the fundamental SUSY-breaking parameters. We examine both FP SUSY and its familiar special case, the FP region of mSUGRA/CMSSM, and show that they are beautifully consistent with all particle, astroparticle, and cosmological data, including Higgs boson mass limits, null results from SUSY searches, electric dipole moments, b -> s gamma, B_s -> mu^+ mu^-, the thermal relic density of neutralinos, and dark matter searches. The observed deviation of the muon's anomalous magnetic moment from its standard model value may also be explained in FP SUSY, although not in the FP region of mSUGRA/CMSSM. In light of recent data, we advocate refined searches for FP SUSY and related scenarios with heavy squarks and sleptons, and we present a simplified parameter space to aid such analyses.

Jonathan L. Feng; Konstantin T. Matchev; David Sanford

2011-12-13

167

Focus Point Supersymmetry Redux  

E-print Network

Recent results from Higgs boson and supersymmetry searches at the Large Hadron Collider provide strong new motivations for supersymmetric theories with heavy superpartners. We reconsider focus point supersymmetry (FP SUSY), in which all squarks and sleptons may have multi-TeV masses without introducing fine-tuning in the weak scale with respect to variations in the fundamental SUSY-breaking parameters. We examine both FP SUSY and its familiar special case, the FP region of mSUGRA/CMSSM, and show that they are beautifully consistent with all particle, astroparticle, and cosmological data, including Higgs boson mass limits, null results from SUSY searches, electric dipole moments, b -> s gamma, B_s -> mu^+ mu^-, the thermal relic density of neutralinos, and dark matter searches. The observed deviation of the muon's anomalous magnetic moment from its standard model value may also be explained in FP SUSY, although not in the FP region of mSUGRA/CMSSM. In light of recent data, we advocate refined searches for FP S...

Feng, Jonathan L; Sanford, David

2012-01-01

168

Latin-Focus  

NSDL National Science Digital Library

Launched in 1998, Latin-Focus "enables executives and research analysts alike to find the latest available data from government sources, economic forecasts, market analysis covering economic performance, political risk assessments and financial market developments" in Latin American countries. The front page of the site offers current data as well as daily news and commentary. In the News and Commentary section, the title and source of the article are given, along with the subject country and language. Past articles are archived by date, although the site does note that news briefs may have expired. News may also be searched by country. Along the left side of the screen, eight countries, including Argentina, Brazil, Mexico, and Venezuela, are highlighted. Clicking on one of these countries will bring up a menu consisting of Economic Indicators, Economic Forecasts, Release Calendar, Economic Briefing, Fact Sheet, and Web Directory. Each of these topics links to further subtopics or a variety of short online reports and graphs. This well-designed site offers clear, basic information for those studying economic issues in Latin America.

169

Focus point supersymmetry redux  

NASA Astrophysics Data System (ADS)

Recent results from Higgs boson and supersymmetry searches at the Large Hadron Collider provide strong new motivations for supersymmetric theories with heavy superpartners. We reconsider focus point supersymmetry (FP SUSY), in which all squarks and sleptons may have multi-TeV masses without introducing fine-tuning in the weak scale with respect to variations in the fundamental SUSY-breaking parameters. We examine both FP SUSY and its familiar special case, the FP region of minimal supergravity, also known as the constrained minimal supersymmetric standard model (mSUGRA/CMSSM), and show that they are beautifully consistent with all particle, astroparticle, and cosmological data, including Higgs boson mass limits, null results from SUSY searches, electric dipole moments, b?s?, Bs??+?-, the thermal relic density of neutralinos, and dark matter searches. The observed deviation of the muon’s anomalous magnetic moment from its standard model value may also be explained in FP SUSY, although not in the FP region of mSUGRA/CMSSM. In light of recent data, we advocate refined searches for FP SUSY and related scenarios with heavy squarks and sleptons, and we present a simplified parameter space within mSUGRA/CMSSM to aid such analyses.

Feng, Jonathan L.; Matchev, Konstantin T.; Sanford, David

2012-04-01

170

Ion Motion inthe Adiabatic Focuser  

SciTech Connect

In this paper we numerically study the effect of ion motion in an adiabatic focuser, motivated by a recent suggestion that ion motion in an adiabatic focuser might be significant and even preclude operation of the focuser as previously envisioned. It is shown that despite ion motion the adiabatic focuser should work as well as originally envisioned.

Henestroza, E.; Sessler, A.M.; Yu, S.S.

2006-06-10

171

Stress wave focusing transducers  

SciTech Connect

Conversion of laser radiation to mechanical energy is the fundamental process behind many medical laser procedures, particularly those involving tissue destruction and removal. Stress waves can be generated with laser radiation in several ways: creation of a plasma and subsequent launch of a shock wave, thermoelastic expansion of the target tissue, vapor bubble collapse, and ablation recoil. Thermoelastic generation of stress waves generally requires short laser pulse durations and high energy density. Thermoelastic stress waves can be formed when the laser pulse duration is shorter than the acoustic transit time of the material: {tau}{sub c} = d/c{sub s} where d = absorption depth or spot diameter, whichever is smaller, and c{sub s} = sound speed in the material. The stress wave due to thermoelastic expansion travels at the sound speed (approximately 1500 m/s in tissue) and leaves the site of irradiation well before subsequent thermal events can be initiated. These stress waves, often evolving into shock waves, can be used to disrupt tissue. Shock waves are used in ophthalmology to perform intraocular microsurgery and photodisruptive procedures as well as in lithotripsy to fragment stones. We have explored a variety of transducers that can efficiently convert optical to mechanical energy. One such class of transducers allows a shock wave to be focused within a material such that the stress magnitude can be greatly increased compared to conventional geometries. Some transducer tips could be made to operate regardless of the absorption properties of the ambient media. The size and nature of the devices enable easy delivery, potentially minimally-invasive procedures, and precise tissue- targeting while limiting thermal loading. The transducer tips may have applications in lithotripsy, ophthalmology, drug delivery, and cardiology.

Visuri, S.R., LLNL

1998-05-15

172

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)

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.

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

2014-04-01

173

Cable Diagnostic Focused Initiative  

SciTech Connect

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.

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

2010-12-30

174

Focus Point Supersymmetry in Extended Gauge Mediation  

E-print Network

We propose a small extenion of the minimal gauge mediation through the combination of extended gauge mediation and conformal sequestering. We show that the focus point supersymmetry can be realized naturally, and the ?ne-tuning is signifcantly reduced compared to the minimal gauge mediation and extended gauge mediation without focus point. The Higgs boson mass is around 125 GeV, the gauginos remain light, and the gluino is likely to be detected at the next run of the LHC. However, the multi-TeV squarks is out of the reach of the LHC. The numerical calculation for ?netuning shows that this model remains natural.

Ran Ding; Tianjun Li; Florian Staub; Bin Zhu

2013-12-19

175

Hydrodynamic focusing - a versatile tool  

PubMed Central

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

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

2011-01-01

176

Focusators for laser-branding  

NASA Astrophysics Data System (ADS)

A new method is investigated for synthesis of computer-generated optical elements: focusators that are able to focus the radial-symmetrical laser beam into complex focal contours, in particular into alphanumeric symbols. The method is based on decomposition of the focal contour into segments of straight lines and semi-circles, following corresponding spacing out of the focusator on elementary segments (concentric rings or sectors) and solution of the inverse task of focusing from focusator segments into corresponding elements of the focal contour. The results of numerical computing of the field from synthesized focusators into the letters are presented. The theoretical efficiency of the focusators discussed is no less than 85%. The amplitude masks and the results of operational studies of synthesized focusators are presented.

Doskolovich, L. L.; Kazanskiy, N. L.; Kharitonov, S. I.; Uspleniev, G. V.

177

Microflow cytometers with integrated hydrodynamic focusing.  

PubMed

This study demonstrates the suitability of microfluidic structures for high throughput blood cell analysis. The microfluidic chips exploit fully integrated hydrodynamic focusing based on two different concepts: Two-stage cascade focusing and spin focusing (vortex) principle. The sample--A suspension of micro particles or blood cells--is injected into a sheath fluid streaming at a substantially higher flow rate, which assures positioning of the particles in the center of the flow channel. Particle velocities of a few m/s are achieved as required for high throughput blood cell analysis. The stability of hydrodynamic particle positioning was evaluated by measuring the pulse heights distributions of fluorescence signals from calibration beads. Quantitative assessment based on coefficient of variation for the fluorescence intensity distributions resulted in a value of about 3% determined for the micro-device exploiting cascade hydrodynamic focusing. For the spin focusing approach similar values were achieved for sample flow rates being 1.5 times lower. Our results indicate that the performances of both variants of hydrodynamic focusing suit for blood cell differentiation and counting. The potential of the micro flow cytometer is demonstrated by detecting immunologically labeled CD3 positive and CD4 positive T-lymphocytes in blood. PMID:23571670

Frankowski, Marcin; Theisen, Janko; Kummrow, Andreas; Simon, Peter; Ragusch, Hülya; Bock, Nicole; Schmidt, Martin; Neukammer, Jörg

2013-01-01

178

Feedback through Focus Group Interviews.  

ERIC Educational Resources Information Center

Describes use of focus group interviews in evaluating college career planning and placement services. Discusses components (moderator, group participants, site and equipment, report) of focus group interview and then provides an actual application of the focus group interview in a career center setting. (ABL)

Hartman, Richard I., Arora, Raj

1988-01-01

179

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

PubMed

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

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

2014-12-01

180

Ultrasound-induced calcein release from eLiposomes.  

PubMed

Ultrasound is explored as a method of inducing the release of encapsulated materials from eLiposomes, defined as liposomes containing emulsion droplets. Emulsions were formed using perfluorohexane and perfluoropentane. eLiposomes were formed by folding interdigitated lipid sheets into closed vesicles around the emulsion droplets. Cryogenic transmission electron microscopy was used to verify droplet encapsulation. Self-quenched calcein was also encapsulated inside the vesicles. A fluorometer was used to measure baseline fluorescence, calcein release after ultrasound exposure, and total release from the vesicles. eLiposome samples released 3 to 5 times more of the encapsulated calcein than did controls when exposed to 20-kHz ultrasound. Calcein release increased with exposure time and intensity of ultrasound. eLiposomes with large (400 nm) droplets produced more calcein release than small (100 nm) droplets. These observations suggest that the emulsions are vaporized by ultrasound and that the Laplace pressure in the emulsions has an effect on droplet vaporization. PMID:23062373

Lattin, James R; Pitt, William G; Belnap, David M; Husseini, Ghaleb A

2012-12-01

181

Quantification of the ultrasound induced sedimentation of Microcystis aeruginosa.  

PubMed

It has been known for more than 40 years that vacuolate organisms can be induced to sediment with ultrasound. However, robust indicators are still needed to compare the efficacy of different treatments. A repeatable index is proposed that makes it possible to quantify the ultrasonic induced sedimentation. The procedure is used to monitor the long term sedimentation of Microcystis aeruginosa after sonication. Results reveal that the sedimentation process continues after gas vesicles have fully recovered, although at a slower rate. PMID:24636363

Rodriguez-Molares, Alfonso; Dickson, Sandy; Hobson, Peter; Howard, Carl; Zander, Anthony; Burch, Mike

2014-07-01

182

Ultrasound-induced acoustophoretic motion of microparticles in three dimensions  

NASA Astrophysics Data System (ADS)

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 and 5.33 ?m. 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-?m-diameter particles, allowing for quantitative comparison between theoretical predictions and measurements of the streaming-induced motion of small 0.5-?m-diameter particles.

Muller, P. B.; Rossi, M.; Marín, Á. G.; Barnkob, R.; Augustsson, P.; Laurell, T.; Kähler, C. J.; Bruus, H.

2013-08-01

183

EDITORIAL: Focus on Quantum Control  

NASA Astrophysics Data System (ADS)

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

Rabitz, Herschel

2009-10-01

184

Best focus shift issues from focusing system of ASML PAS-5000/50 steppers  

NASA Astrophysics Data System (ADS)

The best focus shift problem was observed on PAS-5000/50 I- line system. The best focus shift could induce poor resist profile in back-end lithography exposure processes, and caused blind via-holes or damage on conductor lines after plasma etch. The effects of topography change, pattern layout and focus laser spot position on the best focus determination were proved related to the focusing system design, single point focus detection with small size probe beam. of PAS-5000/50 steppers. In the main paper, the weak points of the design are pointed out, i.e. the unwanted information due to its dependence on step topography and layout may be collected and cause defocused resist profile during focusing. Though the application of dark-tone digitized scribe line design on dielectric layers reduces step topography discrepancy between main cell and scribe line and partially solves the problems; however, the complete solutions rely on the fundamental improvements on the stepper focusing algorithm.

Tseng, Ming-Huei; Lai, Feng-Liang; Turn, Li-Kong

1999-04-01

185

Ground-penetrating synthetic aperture radar focusing algorithm  

SciTech Connect

This paper presents an algorithm for image reconstruction of ground-penetrating synthetic aperture radar that can be implemented in real time. The algorithm permits underground focusing. The algorithm was successfully demonstrated at scale using a Ka-band radar in the laboratory that has 1 cm range resolution. The equipment utilized objects on the surface and at depths of 7.5 and 15 cm. With the imaging set for focus at the surface, the buried objects were not detected. The buried objects were detected and resolved to the theoretical limits with the focus appropriately set, with the surface object detected but blurred. Thus, the algorithm provides better detection and resolution of underground objects than algorithms sans underground focus, and also permits an estimate of the depth.

Cribbs, R.W. [Folsom Research, Inc., Folsom, CA (United States)

1994-12-31

186

Initiative for Explosives Detection  

E-print Network

Initiative for Explosives Detection Highly Concealed Bulk Explosives Detection This focus area emphasizes the detection of explosives or IEDs hidden in vehicles, buildings or various types of containers of highly concealed explosives include the development of enhanced energy sources, improved electronics

187

Dynamic isoelectric focusing for proteomics.  

PubMed

Dynamic isoelectric focusing is a new technique that is related to capillary isoelectric focusing but uses additional high-voltage power supplies to provide control over the shape of the electric field within the capillary. Manipulation of the electric field changes the pH gradient, enabling both the location and width of the focused protein bands to be controlled. The proteins can be migrated to a designated sampling point while remaining focused, where they can be collected for further analysis. This ability to collect and isolate the protein bands while maintaining a high peak capacity demonstrates that dynamic isoelectric focusing has great potential as a first dimension in a multidimensional separation system. Dynamic isoelectric focusing can achieve a peak capacity of over 1000, as shown by both mass spectrometry analysis and direct imaging. PMID:16970328

Montgomery, Robbie; Jia, Xuegang; Tolley, Luke

2006-09-15

188

Focused ultrasound for early detection of tooth decay  

Microsoft Academic Search

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.

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

2009-01-01

189

Focusing light using negative refraction  

Microsoft Academic Search

A slab of negatively refracting material, thickness d, can focus an image at a distance 2d from the object. The negative slab cancels an equal thickness of positive space. This result is a special case of a much wider class of focusing: any medium can be optically cancelled by an equal thickness of material constructed to be an inverted mirror

J. B. Pendry; S. Anantha Ramakrishna

2003-01-01

190

Depression, regulatory focus, and motivation  

Microsoft Academic Search

The present study examined relationships between chronic regulatory focus and motivation to improve upon academic outcomes in a sample of individuals varying in degree of hopelessness depression (HD) symptoms. Participants recalled a recent negative academic outcome, completed a measure of regulatory focus, reported their subsequent motivation to improve upon future academic outcomes, and then indicated whether their grades on examinations,

Audrey K. Miller; Keith D. Markman

2007-01-01

191

Focusing linear arrays operating in a sequential mode  

Microsoft Academic Search

The authors describe multiple target detection using a linear array, operated in the sequential mode. In this approach, the firing of the elements is sequential: one element is transmitting with all the elements receiving. A novel processing technique is presented which allows multiple target detection without tapering or phase shifting hardware, and which includes focusing at any range. Three examples

J. G. Kim; B. R. Mahafza; R. J. Polge

1989-01-01

192

Prime focus instrument of prime focus spectrograph for Subaru telescope  

NASA Astrophysics Data System (ADS)

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.

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

193

Child-Focused Versus School-Focused Sociometrics  

Microsoft Academic Search

We explored the feasibility and usefulness of collecting peer sociometric data on a sample of children from across southeastern New England who were being followed in a community-based longitudinal study. Applying what has typically been a school-focused research methodology to this child-focused follow-up highlighted challenges faced by applied researchers wanting to make use of this powerful method for assessing social

Audrey L. Zakriski; Ronald Seifer; R. Christopher Sheldrick; Mitchell J. Prinstein; Susan Dickstein; Arnold J. Sameroff

1999-01-01

194

Plutonium focus area: Technology summary  

SciTech Connect

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.

NONE

1996-03-01

195

Wideband focused transducer array for optoacoustic tomography  

NASA Astrophysics Data System (ADS)

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.

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

2009-11-01

196

Focusing liquid microjets with nozzles  

NASA Astrophysics Data System (ADS)

The stability of flow focusing taking place in a converging-diverging nozzle, as well as the size of the resulting microjets, is examined experimentally in this paper. The results obtained in most aspects of the problem are similar to those of the classical plate-orifice configuration. There is, however, a notable difference between flow focusing in nozzles and in the plate-orifice configuration. In the former case, the liquid meniscus oscillates laterally (global whipping) for a significant area of the control parameter plane, a phenomenon never observed when focusing with the plate-orifice configuration. Global whipping may constitute an important drawback of flow focusing with nozzles because it reduces the robustness of the technique.

Acero, A. J.; Ferrera, C.; Montanero, J. M.; Gañán-Calvo, A. M.

2012-06-01

197

Wayside Teaching: Focusing on Relationships  

NSDL National Science Digital Library

Wayside teaching focuses on building and maintaining positive relationships with students. Teachers can implement certain wayside teaching practices to end the year in a positive way and begin preparing for the next school year.

Powell, Sara D.

2011-05-01

198

Wolter Optics for Neutron Focusing  

NASA Technical Reports Server (NTRS)

Focusing optics based on Wolter optical geometries developed for x-ray grazing incidence beams can be designed for neutron beams. Wolter optics are formed by grazing incidence reflections from two concentric conic sections (for example, a paraboloid and a hyperboloid). This has transformed observational X-ray astronomy by increasing the sensitivity by many orders of magnitude for research in astrophysics and cosmology. To increase the collection area, many reflecting mirrors of different diameters are nested with a common focal plane. These mirrors are fabricated using nickel-electroformed replication techniques. We apply these ideas to neutron focusing using nickel mirrors. We show an initial test of a conical mirror using a beam of cold neutrons. key words: electroformed nickel replication, focusing optics, grazing angle incidence, mirror reflection, neutron focusing, Wolter optics

Mildner, D. F. R.; Gubarev, M. V.

2010-01-01

199

Focusing light through living tissue  

NASA Astrophysics Data System (ADS)

Tissues such as skin, fat or cuticle are non-transparent because inhomogeneities in the tissue scatter light. We demonstrate experimentally that light can be focused through turbid layers of living tissue, in spite of scattering. Our method is based on the fact that coherent light forms an interference pattern, even after hundreds of scattering events. By spatially shaping the wavefront of the incident laser beam, this interference pattern was modified to make the scattered light converge to a focus. In contrast to earlier experiments, where light was focused through solid objects, we focused light through living pupae of Drosophila melanogaster. We discuss a dynamic wavefront shaping algorithm that follows changes due to microscopic movements of scattering particles in real time. We relate the performance of the algorithm to the measured timescale of the changes in the speckle pattern and analyze our experiment in the light of Laser Doppler flowmetry. Applications in particle tracking, imaging, and optical manipulation are discussed.

Vellekoop, I. M.; Aegerter, C. M.

2010-02-01

200

Focus On.... Organic Farming and  

E-print Network

and standards........................................................... 9 Organic food and organisations concerned with organic farming that have been indexed in the Agriculture, Food and ForestryFocus On.... Organic Farming and Agriculture This resource guide aims to provide useful, detailed

Miranda, Eduardo Reck

201

Statistical Mechanics with focus on  

E-print Network

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

Johannesson, Henrik

202

Focus and VP Ellipsis1  

PubMed Central

In spoken English, pitch accents can convey the focus associated with new or contrasted constituents. Two listening experiments were conducted to determine whether accenting a subject makes its predicate a more tempting antecedent for an elided verb phrase, presumably because the accent helps focus the subject of the antecedent clause, increasing its likelihood of contrasting with the subject of the elided clause. The results of Experiment 1 supported the predictions of this “contrasted remnant hypothesis” but in principle could also be caused by listeners avoiding antecedents containing a focused (F-marked) constituent. Experiment 2 disconfirmed the hypothesis that listeners avoid antecedents containing a focused constituent, although pitch accents within a potential antecedent VP affected ellipsis resolution. PMID:17518101

Frazier, Lyn; Clifton, Charles; Carlson, Katy

2006-01-01

203

Wayside Teaching: Focusing on Relationships  

ERIC Educational Resources Information Center

Wayside teaching focuses on building and maintaining positive relationships with students. Teachers can implement certain wayside teaching practices to end the year in a positive way and begin preparing for the next school year.

Powell, Sara Davis

2011-01-01

204

Nature Web Focus: Ocean Genomics  

NSDL National Science Digital Library

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.

2003-01-01

205

Focusators at letters diffraction design  

Microsoft Academic Search

A new method is investigated for synthesis of computer-generated optical elements to focusate the radial-symmetrical laser beam into the complex focal contours--in particular, into the alphabetical-digital symbols. The method is based on decomposition of the focal contour by segments of the straight lines and half-circumferences, following corresponding spacing out of the focusator on elementary segments with a ring shape and

Mikhail A. Golub; Leonid L. Doskolovich; Nikolay L. Kazanskiy; Sergey I. Kharitonov; Iosif N. Sisakian; Viktor A. Soifer

1991-01-01

206

A continuous plasma final focus  

SciTech Connect

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} {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. Three numerical examples are considered. 38 refs., 2 figs., 1 tab.

Whittum, D.H.

1990-02-01

207

Depth perception by controlling focus  

NASA Astrophysics Data System (ADS)

Vision systems are a possible choice to obtain sensorial data about the world in robotic systems. To obtain three-dimensional information using vision we can use different computer vision techniques such as stereo, motion, or focus. In particular, this work explores focus to obtain depth or structure perception of the world. In practice, focusing can be obtained by displacing the sensor plate with respect to the image plane, by moving the lens, or by moving the object with respect to the optical system. Moving the lens or sensor plate with respect to each other causes changes of the magnification and corresponding changes on the object coordinates. In order to overcome these problems, we propose varying the degree of focusing by moving the camera with respect to the object position. In our case, the camera is attached to the tool of a manipulator in a hand-eye configuration, with the position of the camera always known. This approach ensures that the focused areas of the image are always subjected to the same magnification. To measure the focus quality we use operators to evaluate the quantity of high-frequency components on the image. Different types of these operators were tested and the results compared.

Dias, Jorge M.; Araujo, Helder; Batista, Joao E.; de Almeida, Anibal T.

1992-04-01

208

Experimental verification of theoretical in vivo ultrasound heating using cobalt detected magnetic resonance  

Microsoft Academic Search

Conventional methods of measuring heating in vivo are invasive and therefore interfere with heat propagation. For the first time, ultrasound-induced temperature increases in living specimens have been estimated theoretically and measured experimentally using a noninvasive technique. In vivo ultrasound-induced temperature increases in the livers of rats show consistent results between: (1) a theoretical ultrasound point-source solution for a measured ultrasound

Nadine Barrie Smith; Andrew G. Webb; D. Scott Ellis; Lisa J. Wilmes; William D. O'Brien Jr

1995-01-01

209

CCD Detection System User Manual  

E-print Network

SYNAPSE CCD Detection System User Manual Part Number 81100 ­ Revision 2 #12;ii Copyright © November-up......................................................................................................................... 19 CCD Focus and Alignment on the Spectrograph

Rubloff, Gary W.

210

Early Detection Research Worldwide  

Cancer.gov

Genetic research on cancer has grown tremendously in the last decade, and the increase in the number of published research articles has been truly phenomenal. However, molecular and genetic research focusing on the early detection of cancer is still lagging.

211

AXAF SIM focus mechanism study  

NASA Technical Reports Server (NTRS)

The design requirements and initial design concept for the AXAF-I Science Instrument Module (SIM) were reviewed at Ball on September 29, 1993. The concept design SIM focus mechanism utilizes a planetary gearset, with redundant motors, to drive a large ring (called 'main housing bearing') via a spur gearset. This large drive ring actuates three tangent bar links (called 'push rods'), which in turn actuate three levers (called 'pin levers'). Each of the three pin levers rotates an 'eccentric pin,' which in turn moves the base of a bipod flexure in both the radial (normal to optical axis) and axial (focus along optical axis) directions. Three bipod flexures are employed, equally spaced at 120 degrees apart, the base of each being translated in the two directions as described above. A focus adjustment is made by rotating the drive ring, which drives the push rods and therefore the pin levers, which in turn rotate the eccentric pins, finally imparting the two motions to the base of each of the bipod flexures. The axial translation (focus adjustment) of the focused structure is the sum of the direct axial motion plus axial motion which comes from uniformly squeezing the three bipod bases radially inward. SAO documented the following concerns regarding the focus mechanism in memo WAP-FY94-001, dated October 7, 1993: (1) The focus adjustment depends, in large part, on the structural properties (stiffnesses and end fixities) of the bipod flexures, push rods, pin levers and eccentric pins. If these properties are not matched very well, then lateral translations as well as unwanted rotations of the focussed structure will accompany focus motion. In addition, the stackup of linkage tolerances and any nonuniform wear in the linkages will result in the same unwanted motions. Thermal gradients will also affect these motions. At the review Ball did not present supporting analyses to support their choice of this design concept. (2) The proposed 'primary' method of measuring focus is by counting motor steps. The 'backup' method is by a pot mounted on the drive ring. Neither method provides for a direct measurement of the quantity desired (focus position). This is of concern because of the long and indirect relationship between focus and the sensed quantity (drive ring rotation). There are three sinusoidal relationships and structural stiffness in the path, and the resulting calibration is likely to be highly nonlinear. These methods would require an accurate ground calibration. (3) Ground calibration (and verification) of focus vs. drive position must be done in 1-g on the ground. This calibration will be complicated by both the structural characteristics of the bipods and the fact that the CG of the translating portion of the SIM is not on the optical axis (thereby causing unwated rotations and changing the focus position vs. motor step and pot readout relationships). The SIM translating weight could be offloaded, but the calibration then becomes sensitive to any errors in offloading (both magnitude and direction). There are concerns as to whether a calibration to the required accuracy can be accomplished on the ground. (4) The choice of a potentiometer as the focus position sensor is questionable in terms of reliability for a five year mission. The results of SAO's study of items 1, 2 and 3 described above are presented in this report.

Tananbaum, H. D.; Whitbeck, E.

1994-01-01

212

AXAF SIM focus mechanism study  

NASA Astrophysics Data System (ADS)

The design requirements and initial design concept for the AXAF-I Science Instrument Module (SIM) were reviewed at Ball on September 29, 1993. The concept design SIM focus mechanism utilizes a planetary gearset, with redundant motors, to drive a large ring (called 'main housing bearing') via a spur gearset. This large drive ring actuates three tangent bar links (called 'push rods'), which in turn actuate three levers (called 'pin levers'). Each of the three pin levers rotates an 'eccentric pin,' which in turn moves the base of a bipod flexure in both the radial (normal to optical axis) and axial (focus along optical axis) directions. Three bipod flexures are employed, equally spaced at 120 degrees apart, the base of each being translated in the two directions as described above. A focus adjustment is made by rotating the drive ring, which drives the push rods and therefore the pin levers, which in turn rotate the eccentric pins, finally imparting the two motions to the base of each of the bipod flexures. The axial translation (focus adjustment) of the focused structure is the sum of the direct axial motion plus axial motion which comes from uniformly squeezing the three bipod bases radially inward. SAO documented the following concerns regarding the focus mechanism in memo WAP-FY94-001, dated October 7, 1993: (1) The focus adjustment depends, in large part, on the structural properties (stiffnesses and end fixities) of the bipod flexures, push rods, pin levers and eccentric pins. If these properties are not matched very well, then lateral translations as well as unwanted rotations of the focussed structure will accompany focus motion. In addition, the stackup of linkage tolerances and any nonuniform wear in the linkages will result in the same unwanted motions. Thermal gradients will also affect these motions. At the review Ball did not present supporting analyses to support their choice of this design concept. (2) The proposed 'primary' method of measuring focus is by counting motor steps. The 'backup' method is by a pot mounted on the drive ring. Neither method provides for a direct measurement of the quantity desired (focus position). This is of concern because of the long and indirect relationship between focus and the sensed quantity (drive ring rotation). There are three sinusoidal relationships and structural stiffness in the path, and the resulting calibration is likely to be highly nonlinear. These methods would require an accurate ground calibration. (3) Ground calibration (and verification) of focus vs. drive position must be done in 1-g on the ground. This calibration will be complicated by both the structural characteristics of the bipods and the fact that the CG of the translating portion of the SIM is not on the optical axis (thereby causing unwanted rotations and changing the focus position vs. motor step and pot readout relationships). focus position sensor is questionable in terms of reliability for a five year mission. The results of SAO's study of items 1, 2 and 3 described above are presented in this report.

Tananbaum, H. D.; Whitbeck, E.

1994-02-01

213

Focus cues affect perceived depth  

PubMed Central

Depth information from focus cues—accommodation and the gradient of retinal blur—is typically incorrect in three-dimensional (3-D) displays because the light comes from a planar display surface. If the visual system incorporates information from focus cues into its calculation of 3-D scene parameters, this could cause distortions in perceived depth even when the 2-D retinal images are geometrically correct. In Experiment 1 we measured the direct contribution of focus cues to perceived slant by varying independently the physical slant of the display surface and the slant of a simulated surface specified by binocular disparity (binocular viewing) or perspective/texture (monocular viewing). In the binocular condition, slant estimates were unaffected by display slant. In the monocular condition, display slant had a systematic effect on slant estimates. Estimates were consistent with a weighted average of slant from focus cues and slant from disparity/texture, where the cue weights are determined by the reliability of each cue. In Experiment 2, we examined whether focus cues also have an indirect effect on perceived slant via the distance estimate used in disparity scaling. We varied independently the simulated distance and the focal distance to a disparity-defined 3-D stimulus. Perceived slant was systematically affected by changes in focal distance. Accordingly, depth constancy (with respect to simulated distance) was significantly reduced when focal distance was held constant compared to when it varied appropriately with the simulated distance to the stimulus. The results of both experiments show that focus cues can contribute to estimates of 3-D scene parameters. Inappropriate focus cues in typical 3-D displays may therefore contribute to distortions in perceived space. PMID:16441189

Watt, Simon J.; Akeley, Kurt; Ernst, Marc O.; Banks, Martin S.

2007-01-01

214

Fast and precise continuous focusing with focus tunable lenses  

NASA Astrophysics Data System (ADS)

Focusing in milliseconds without translational mechanics involved is possible with electrically tunable lenses. Fast shape-changing lenses enable fast imaging systems which can focus at distances from infinity to a few centimeters with a high optical quality. Furthermore, rapid laser processing in three dimensions is realized without mechanical translation of the focusing lens or the sample. With tunable lenses the entire optics can be made compact, robust and abrasion-free. Different configurations are discussed, how to integrate the tunable lens in the optical path. For machine vision applications, the achievable optical quality depends on the chosen combination of the tunable lens with a fixed focal length lens and a camera. It is recommended to use a fixed focus lens with a short distance between the stop position and the front of the lens. Furthermore, important points are presented how to achieve optimal performance in laser processing applications such as orientation and position of the tunable lens and the diameter of the beam incident on the lens. Additionally, different approaches will be discussed for monitoring the focal length of the tunable lens. The focal length of the tunable lens is sensitive to temperature changes, as the lens material is a fluid. However, in contrast to conventional lenses, the focal length of the tunable lens can be corrected electrically. For that purpose, the tunable lens exhibits an integrated temperature sensor for temperature compensation. Also optical feedback solutions will be presented for applications requiring highest precision and tracking of the absolute focal length value.

Casutt, Selina; Bueeler, Michael; Blum, Mark; Aschwanden, Manuel

2014-03-01

215

Prime Focus Instrument of Prime Focus Spectrograph for Subaru Telescope  

E-print Network

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 (A&G) 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 Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations within the required accuracy.

Wang, Shiang-Yu; Schwochert, Mark A; Huang, Pin-Jie; Kimura, Masahiko; Chen, Hsin-Yo; Reiley, Dan 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

2014-01-01

216

Magnetically focused liquid drop radiator  

DOEpatents

A magnetically focused liquid drop radiator for application in rejecting energy from a spacecraft, 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.

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

1984-12-10

217

A continuous plasma final focus  

SciTech Connect

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.

Whittum, D.H.

1989-11-01

218

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.

2013-07-01

219

Focused X-ray source  

DOEpatents

Disclosed is an intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator. 8 figs.

Piestrup, M.A.; Boyers, D.G.; Pincus, C.I.; Maccagno, P.

1990-08-21

220

Standards and Assessment. IDRA Focus.  

ERIC Educational Resources Information Center

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…

IDRA Newsletter, 1997

1997-01-01

221

Master of Education focusing on  

E-print Network

Master of Education focusing on Urban Aboriginal Education A Collaborative Initiative between the Faculty of Education, York University and the TDSB Aboriginal Education Centre In response to the need, the Faculty of Education at York University in collaboration with the TDSB Aboriginal Education Centre

222

your position is our focus  

E-print Network

! chips! comprise! a! complete! GPS! solution! from! antenna! input! to! navigation! data! output.! The! ATR0620! contains! the! integrated! ARM7TDMI,! ROM! for! the! GPS! firmware! and! on-chip! RAM.! ! No! ! your position is our focus ATR GPS Receiver Chipset ANTARIS ® Positioning Engine

Berns, Hans-Gerd

223

focusing on research still growing  

E-print Network

of pharmaceutical anD pharmacological sciences PSYCHOLOGY Department of philosophy, sociology, eDucation anD applieD49 focusing on research still growing SOCIAL SCIENCES AND HUMANITIES ECONOMICS AND STATISTICS Department of economics anD management Department of statistical sciences HISTORY, PHILOSOPHY AND PEDAGOGY

Cesare, Bernardo

224

SALT prime focus payload development  

Microsoft Academic Search

The Southern African Large Telescope (SALT), currently being erected in Sutherland, South Africa, will be the largest single optical telescope in the southern hemisphere, and the 4th largest telescope in the world, when it is completed in late 2004. The SALT design is based on the Hobby-Eberly Telescope. The prime focus payload design presented structural and layout challenges, since four

Schalk W. P. Esterhuyse; Janus D. Brink; Cornelius J. A. Nel; Arek Swat

2004-01-01

225

Focused X-ray source  

DOEpatents

An intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator.

Piestrup, Melvin A. (Woodside, CA); Boyers, David G. (Mountain View, CA); Pincus, Cary I. (Sunnyvale, CA); Maccagno, Pierre (Stanford, CA)

1990-01-01

226

Focus Issue: Signals to Neurodegeneration  

NSDL National Science Digital Library

Neurodegenerative diseases exact a tremendous toll on afflicted individuals and their families. Understanding the underlying signaling cascades that are perturbed by or contribute to neurodegeneration may identify new therapeutic targets or improve current therapies. The pieces in this Focus Issue of Science Signaling discuss molecular mechanisms and signaling pathways implicated in the pathologies of Parkinson's, Alzheimer's, and Huntington's diseases.

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

2009-07-21

227

Undergraduate Research Symposium focusing on  

E-print Network

ability to harness energy from ocean waves and tides, the capability to produce power from wind turbines and to implement alternative and renewable forms of energy in the 21st century. There is hope for our generationUndergraduate Research Symposium focusing on Energy and Climate Change Tuesday, November 16 5

Jiang, Huiqiang

228

Focus Issue on Metamaterials INTRODUCTION  

E-print Network

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

Shalaev, Vladimir M.

229

Research Focus Engineering regulatory RNAs  

E-print Network

as a passive messenger between the genome and the proteome to actively controlling the expression patternsResearch Focus Engineering regulatory RNAs Eric A. Davidson1 and Andrew D. Ellington1,2 1 Institute of conformation-switching riboswitches in the 50 untranslated regions (UTRs) of genes that control transcription

Collins, James J.

230

Changing Focus: Women's Perimenopausal Journey  

Microsoft Academic Search

In this article I revisit the results of research completed in the mid-1990s and recently reviewed with women's updated input. The basic social process named “changing focus” that women use as they negotiate the perimenopausal transition is discussed. This process consists of five parts: monitoring the voice of the woman within, listening to the voices of others, integrating the wisdom,

Cynthia Ricci McCloskey

2012-01-01

231

Research Focus Glutamate receptors: variation  

E-print Network

Research Focus Glutamate receptors: variation in structure­function coupling Anders S. Kristensen1 transmission in the CNS relies almost entirely on the neurotransmitter glutamate and its family of ion channel different mechanisms to translate agonist binding into channel opening. Working hypotheses for glutamate

Traynelis, Stephen F.

232

World History. Focus on Economics.  

ERIC Educational Resources Information Center

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…

Caldwell, Jean; Clark, James; Herscher, Walter

233

FOCUS ON CAREERS GLOBAL STUDIES  

E-print Network

and media culture and globalization diplomacy economic development English-language teaching foreign serviceFOCUS ON CAREERS GLOBAL STUDIES Brandeis University Graduate School of Arts and Sciences LOBAL STUDIES graduate study at Brandeis provides a broad perspective of global institutions, critical issues

Snider, Barry B.

234

Creating Wave-Focusing Materials  

E-print Network

Basic ideas for creating wave-focusing materials by injecting small particles in a given material are described. The number of small particles to be injected around any point is calculated. Inverse scattering problem with fixed wavenumber and fixed incident direction of the plane acoustic wave is formulated and solved.

A. G. Ramm

2008-05-16

235

Comparison of plasma focus calculations  

Microsoft Academic Search

A simple model for the current history of plasma focus experiments is presented. The presence of a leak current which does not pass through the plasma sheath is allowed. Results are found to compare quite well with those of much more sophisticated two-dimensional magnetohydrodynamic calculations. For the Frascati experiment, which has detailed current measurements, computed results do not agree with

P. G. Eltgroth

1982-01-01

236

Technology for Education. IDRA Focus.  

ERIC Educational Resources Information Center

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…

IDRA Newsletter, 1998

1998-01-01

237

Winter 2010 EVENTS FOCUS: RUSSIA  

E-print Network

and Property Rights in Late Imperial Russia." Ekaterina Pravilova, assistant professor of history, PrincetonWinter 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

Eustice, Ryan

238

Tsunami Amplification due to Focusing  

NASA Astrophysics Data System (ADS)

Tsunami runup measurements over the periphery of the Pacific Ocean after the devastating Great Japan tsunami of 11 March 2011 showed considerable variation in far-field and near-field impact. This variation of tsunami impact have been attributed to either directivity of the source or by local topographic effects. Directivity arguments alone, however, cannot explain the complexity of the radiated patterns in oceans with trenches and seamounts. Berry (2007, Proc. R. Soc. Lond. A 463, 3055-3071) discovered how such underwater features may concentrate tsunamis into cusped caustics and thus cause large local amplifications at specific focal points. Here, we examine focusing and local amplification, not by considering the effects of underwater diffractive lenses, but by considering the details of the dipole nature of the initial profile, and propose that certain regions of coastline are more at-risk, not simply because of directivity but because typical tsunami deformations create focal regions where abnormal tsunami wave height can be registered (Marchuk and Titov, 1989, Proc. IUGG/IOC International Tsunami Symposium, Novosibirsk, USSR). In this work, we present a new general analytical solution of the linear shallow-water wave equation for the propagation of a finite-crest-length source over a constant depth without any restriction on the initial profile. Unlike the analytical solution of Carrier and Yeh (2005, Comp. Mod. Eng. & Sci. 10(2), 113-121) which was restricted to initial conditions with Gaussian profiles and involved approximation, our solution is not only exact, but also general and allows the use of realistic initial waveform such as N-waves as defined by Tadepalli and Synolakis (1994, Proc. R. Soc. Lond. A 445, 99-112). We then verify our analytical solution for several typical wave profiles, both with the NOAA tsunami forecast model MOST (Titov and Synolakis, 1998, J. Waterw. Port Coast. Ocean Eng. 124(4), 157-171) which is validated and verified through (Synolakis et al., 2008, Pure Appl. Geophys. 165(11-12), 2197-2228), and with a Boussinesq model, to illustrate the role focusing can play for different initial conditions, and to show the robust nature of focusing with respect to dispersion. We also show how the focusing effect might have played a role in the 17 July 1998 Papua New Guinea and 17 July 2006 Java events, and also the 11 March 2011 Great Japan earthquake and tsunami. Our results strongly imply that focusing increases the shoreline amplification of the tsunami.; Schematic of focusing; initial displacement (upper left), wave evolution (upper right, lower left), maximum wave amplitude with focusing (lower right).

Moore, C. W.; Kanoglu, U.; Titov, V. V.; Aydin, B.; Spillane, M. C.; Synolakis, C. E.

2012-12-01

239

FOREWORD: Focus on Advanced Ceramics Focus on Advanced Ceramics  

NASA Astrophysics Data System (ADS)

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.

Ohashi, Naoki

2011-06-01

240

Sensor noise fault detection  

Microsoft Academic Search

Current sensor FDIR (fault detection, isolation, & recovery) generally focuses on sensor bias and drift anomalies, which require models. However, dead sensors and excessive noise faults are more common in practice. The latter two faults are interesting in that they can be detected using only the measurements from each sensor. The objective of this paper is to show a few

Steve Rogers

2003-01-01

241

Experimental Phased Array Focusing in Pipe Using Ultrasonic Guided Waves  

NASA Astrophysics Data System (ADS)

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.

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

2005-04-01

242

Beam dynamics in the SLC final focus system  

SciTech Connect

The SLC luminosity is reached by colliding beams focused to about 2 ..mu..m transverse sizes. The Final Focus System (FFS) must enable, beyond its basic optical design, the detection and correction of errors accumulated in the system. In this paper, after summarizing the design, we review the sensitivity to such errors and the ability to correct them. The overall tuning strategy involves three phases: single beam spot minimization, steering the beams in collision and luminosity optimization with beam-beam effects.

Bambade, P.S.

1987-06-01

243

Fusing images with different focuses using support vector machines  

Microsoft Academic Search

Many vision-related processing tasks, such as edge detection, image segmentation and stereo matching, can be performed more easily when all objects in the scene are in good focus. However, in practice, this may not be always feasible as optical lenses, especially those with long focal lengths, only have a limited depth of field. One common approach to recover an everywhere-in-focus

Shutao Li; James T. Kwok; Ivor W. Tsang; Yaonan Wang

2004-01-01

244

Focused electron beam in pyroelectric electron probe microanalyzer  

SciTech Connect

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.

Imashuku, Susumu; Imanishi, Akira; Kawai, Jun [Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan)] [Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan)

2013-07-15

245

Focus Issue: Signaling Across Membranes  

NSDL National Science Digital Library

This week’s issues of Science and Science’s STKE focus on movement of molecules and information across cellular membranes. Science highlights the mechanisms by which proteins, ions, and DNA cross the membranes of eukaryotic and prokaryotic cells. STKE addresses how information is transmitted across cell membranes to allow cells to communicate with each other and to respond to signals in their environments.

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

2005-12-06

246

Focused Observation: Recording A Hike  

NSDL National Science Digital Library

Students will learn how to focus their observations during a nature hike. The children record their observations on a sheet of paper which has been horizontally divided into thirds. Alongside the divisions is a stick figure with the top of the head touching the top line and the knees directly touching the bottom line. This way the paper is divided to record things observed above a student's head, below the student's knees and in between the student's head and knees.

Lisa Arcand ,Battle Creek Elementary School, St. Paul, Mn

2012-03-18

247

Faculty Focus: Robert J. Naiman  

E-print Network

1 1 From the Director Faculty Focus: Robert J. Naiman Alumni Update Consider a Gift The Alaska t u n i v e r S i t y o f W A S h i n g t o n #12;2 Courtesy of Robert Naiman Editor's note Bioenergetics of herbivorous pupfish population (Cyprinodon) and its algal food supply in a thermal stream en.wikipedia.org/wiki/Robert_J._Naiman

Washington at Seattle, University of

248

Focus Issue: Rendering Resistance Futile  

NSDL National Science Digital Library

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.

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

2011-03-29

249

Focusing properties of small lenses  

NASA Astrophysics Data System (ADS)

The potential use of small substrate lenses for coupling to antennas at millimeter wave frequencies is investigated by analyzing the focusing properties of dielectric spheres with quarter-wave matching layers. The fields and the power density are calculated at various points within the sphere to learn how the focusing deteriorates as the lens is made smaller. The absorption loss of the lens is also calculated. The calculations show that quartz spheres with quarter-wave matching layers can exhibit good focusing properties down to a radius of about half a free space wavelength. This minimum radius was found to increase almost linearly with the refractive index of the lens. The calculations also indicate that at 94 GHz the absorption losses of fused quartz, silicon and gallium arsenide lenses, with radii of one free space wavelength or less, are less than 0.2 dB. As the minimum diameter or a quartz lens is comparable with the spot size in free space, it should be possible to build an imaging lens array in which each lens will act as a separate imaging element.

Kasilingam, Dayalan; Rutledge, David

1986-10-01

250

Gravitationally Focused Dark Matter around Compact Stars  

NASA Astrophysics Data System (ADS)

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 ?-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.

Bromley, Benjamin C.

2011-12-01

251

The quest for customer focus.  

PubMed

Companies have poured enormous amounts of money into customer relationship management, but in many cases the investment hasn't really paid off. That's because getting closer to customers isn't about building an information technology system. It's a learning journey-one that unfolds over four stages, requiring people and business units to coordinate in progressively more sophisticated ways. The journey begins with the creation of a companywide repository containing each interaction a customer has with the company, organized not by product, purchase, or location, but by customer. Communal coordination is what's called for at this stage, as each group contributes its information to the data pool separately from the others and then taps into it as needed. In the second stage, one-way serial coordination from centralized IT through analytical units and out to the operating units allows companies to go beyond just assembling data to drawing inferences. In stage three, companies shift their focus from past relationships to future behavior. Through symbiotic coordination, information flows back and forth between central analytic units and various organizational units like marketing, sales, and operations, as together they seek answers to questions like "How can we prevent customers from switching to a competitor?" and "Who would be most likely to buy a new product in the future"? In stage four, firms begin to move past discrete, formal initiatives and, through integral coordination, bring an increasingly sophisticated understanding oftheir customers to bear in all day-to-day operations. Skipping stages denies organizations the sure foundation they need to build a lasting customer-focused mind-set. Those that recognize this will invest their customer relationship dollars much more wisely-and will see their customer-focusing efforts pay offon the bottom line. PMID:15807042

Gulati, Ranjay; Oldroyd, James B

2005-04-01

252

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.

2009-11-24

253

Focus Issue: Uncovering Immunological Secrets  

NSDL National Science Digital Library

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.

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

2007-08-07

254

Focus on topological quantum computation  

NASA Astrophysics Data System (ADS)

Topological quantum computation started as a niche area of research aimed at employing particles with exotic statistics, called anyons, for performing quantum computation. Soon it evolved to include a wide variety of disciplines. Advances in the understanding of anyon properties inspired new quantum algorithms and helped in the characterization of topological phases of matter and their experimental realization. The conceptual appeal of topological systems as well as their promise for building fault-tolerant quantum technologies fuelled the fascination in this field. This ‘focus on’ collection brings together several of the latest developments in the field and facilitates the synergy between different approaches.

Pachos, Jiannis K.; Simon, Steven H.

2014-06-01

255

Focus on topological quantum computation  

E-print Network

Topological quantum computation started as a niche area of research aimed at employing particles with exotic statistics, called anyons, for performing quantum computation. Soon it evolved to include a wide variety of disciplines. Advances in the understanding of anyon properties inspired new quantum algorithms and helped in the characterisation of topological phases of matter and their experimental realisation. The conceptual appeal of topological systems as well as their promise for building fault-tolerant quantum technologies fuelled the fascination in this field. This `focus on' brings together several of the latest developments in the field and facilitates the synergy between different approaches.

Jiannis K. Pachos; Steven H. Simon

2014-06-11

256

Rotating apparatus for isoelectric focusing  

NASA Technical Reports Server (NTRS)

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.

Bier, Milan (Inventor)

1986-01-01

257

Focusing properties of mushroom microlenses  

E-print Network

Focusing properties of a novel type photoresist microlens are studied. A specific character of the microlens is its mushroom shape. Recently it was predicted and experimentally revealed that such a lens integrated with a light-emitting diode is capable of enhancing its output efficiency and directivity. In our paper we describe the true electromagnetic performance of a mushroom lens by applying a mathematically rigorous method of boundary integral equations. Numerical results are presented for the mushroom lens illuminated with a plane E-polarized wave and include figures describing the evolution of the lens focal spot and near field maps.

Boriskin, A V; Benson, T; Sewell, P; Nosich, A I

2010-01-01

258

[Fulguration of extrasystolic ventricular focus].  

PubMed

A case is presented of symptomatic premature ventricular contractions refractory to drug therapy with right bundle branch block QRS morphology and left axis deviation in a 68-year-old female without structural heart disease. Endocardial mapping localized the extrasystolic focus at meso-inferoapical region of the left ventricular septum suggesting an origin from the Purkinje network of the left posterior fascicle. Catheter ablation with direct-current energy abolished extrasystolic complexes, without complications. The patient remained asymptomatic over a follow-up of 3 months. PMID:7543744

Velázquez Rodríguez, E; Rosas, F; Frank, R; Fontaine, G; Tonet, J; Lascault, G; Gallais, Y

1995-01-01

259

Micellar affinity gradient focusing: a new method for electrokinetic focusing.  

PubMed

This report describes a new method for the concentration and separation of neutral and/or hydrophobic analytes based on a combination of the analytes' electrophoretic mobility, and affinity for partitioning into a micellar phase. Micellar affinity gradient focusing (MAGF) works by creating a gradient in the micellar retention factor. An electric field is applied along the channel to cause the (negatively charged) micelles to move from the region of high retention to the region of low retention, and the mobile phase is forced to move from the region of low retention to the region of high retention. Consequently, the analyte moves into the gradient region from both directions where it is concentrated at a point where its total velocity is zero. Different analytes, which interact differently with the micelles, will have zero total velocity at different points along the gradient, and will thereby be simultaneously concentrated and separated. PMID:14971917

Balss, Karin M; Vreeland, Wyatt N; Howell, Peter B; Henry, Alyssa C; Ross, David

2004-02-25

260

Future focus for professional development.  

PubMed

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

Roberts, Nicole K; Coplit, Lisa D

2013-01-01

261

Focusing Telescopes in Nuclear Astrophysics  

NASA Astrophysics Data System (ADS)

This volume is the first of its kind on focusing gamma-ray telescopes. Forty-eight refereed papers provide a comprehensive overview of the scientific potential and technical challenges of this nascent tool for nuclear astrophysics. The book features articles dealing with pivotal technologies such as grazing incident mirrors, multilayer coatings, Laue- and Fresnel-lenses - and even an optic using the curvature of space-time. The volume also presents an overview of detectors matching the ambitious objectives of gamma ray optics, and facilities for operating such systems on the ground and in space. The extraordinary scientific potential of focusing gamma-ray telescopes for the study of the most powerful sources and the most violent events in the Universe is emphasized in a series of introductory articles. Practicing professionals, and students interested in experimental high-energy astrophysics, will find this book a useful reference Link: http://www.springer.com/east/home/generic/search/results?SGWID=5-40109-22-173670274-0

von Ballmoos, Peter

2006-12-01

262

Plutonium focus area. Technology summary  

SciTech Connect

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.

NONE

1997-09-01

263

Development of a Focusing DIRC  

SciTech Connect

Benefiting from the recent introduction of new fast vacuum-based photon detectors with a transit time spread of {sigma}{sub TTS} {approx} 30-150 ps, we are developing a novel RICH detector capable of correcting the chromatic error through good time measurements; we believe that this is the first time such a technique has been demonstrated. We have built and successfully tested a particle identification detector called ''Focusing DIRC''. The concept of the prototype is based on the BaBar DIRC, with several important improvements: (a) much faster pixelated photon detectors based on Burle MCP-PMTs and Hamamatsu MaPMTs, (b) a focusing mirror which allows the photon detector to be smaller and less sensitive to background in future applications, (c) electronics allowing the measurement of single photon timing to better than {sigma} {approx} 100-200ps, which allows a correction of the chromatic error. The detector was tested in a SLAC 10GeV/c electron test beam. This detector concept could be used for particle identification at Super B-factory, ILC, GlueX, Panda, etc.

Benitez, J.; Bedajanek, I.; Leith, D.W.G.S.; Mazaheri, G.; Ratcliff, B.; Suzuki, K.; Schwiening, J.; Uher, J.; Va'vra, J.; /SLAC

2006-12-12

264

Automatic focus control for facsimile camera  

NASA Technical Reports Server (NTRS)

Focus control performs function of automatically focusing facsimile camera throughout object field being scanned. It does this by determining and adjusting focus of imaging sensor accordingly. Since facsimile camera images a scene by scanning discrete strips, it is possible to have entire three-dimensional scene in perfect focus at point of imaging by use of focus control.

Sinclair, A. R.; Katzberg, S. J.; Burcher, E. E.

1973-01-01

265

Visual information foraging in a focus + context visualization  

Microsoft Academic Search

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

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

2001-01-01

266

Hormone Purification by Isoelectric Focusing  

NASA Technical Reports Server (NTRS)

Various ground-based research approaches are being applied to a more definitive evaluation of the natures and degrees of electroosmosis effects on the separation capabilities of the Isoelectric Focusing (IEF) process. A primary instrumental system for this work involves rotationally stabilized, horizontal electrophoretic columns specially adapted for the IEF process. Representative adaptations include segmentation, baffles/screens, and surface coatings. Comparative performance and development testing are pursued against the type of column or cell established as an engineering model. Previously developed computer simulation capabilities are used to predict low-gravity behavior patterns and performance for IEF apparatus geometries of direct project interest. Three existing mathematical models plus potential new routines for particular aspects of simulating instrument fluid patterns with varied wall electroosmosis influences are being exercised.

Bier, M.

1985-01-01

267

Focus on artificial frustrated systems  

NASA Astrophysics Data System (ADS)

Frustration in physics is the inability of a system to simultaneously satisfy all the competing pairwise interactions within it. The past decade has seen an explosion of activity involving engineering frustration in artificial systems built using nanotechnology. The most common are the artificial spin ices that comprise arrays of nanomagnets with competing magnetostatic interactions. As well as being physical embodiments of idealized statistical mechanical models in which properties can be tuned by design, artificial spin ices can be studied using magnetic microscopy, allowing all the details of the microstates of these systems to be interrogated, both in equilibrium and when perturbed away from it. This ‘focus on’ collection brings together reports on the latest results from leading groups around the globe in this fascinating and fast-moving field.

Cumings, J.; Heyderman, L. J.; Marrows, C. H.; Stamps, R. L.

2014-07-01

268

Micron-focused ion beamlets  

SciTech Connect

A multiple beam electrode system (MBES) is used to provide focused ion beamlets of elements from a compact microwave plasma. In this study, a honeycomb patterned plasma electrode with micron size apertures for extracting ion beamlets is investigated. The performance of the MBES is evaluated with the help of two widely adopted and commercially available beam simulation tools, AXCEL-INP and SIMION, where the input parameters are obtained from our experiments. A simple theoretical model based upon electrostatic ray optics is employed to compare the results of the simulations. It is found that the results for the beam focal length agree reasonably well. Different geometries are used to optimize the beam spot size and a beam spot {approx}5-10 {mu}m is obtained. The multiple ion beamlets will be used to produce microfunctional surfaces on soft matter like polymers. Additionally, the experimental set-up and plans are presented in the light of above applications.

Chowdhury, Abhishek; Bhattacharjee, Sudeep [Department of Physics, Indian Institute of Technology, Kanpur 208016 (India)

2010-05-15

269

Tank Focus Area pretreatment activities  

SciTech Connect

Plans call for the high-level wastes to be retrieved from the tanks and immobilized in a stable waste form suitable for long-term isolation. Chemistry and chemical engineering operations are required to retrieve the wastes, to condition the wastes for subsequent steps, and to reduce the costs of the waste management enterprise. Pretreatment includes those processes between retrieval and immobilization, and includes preparation of suitable feed material for immobilization and separations to partition the waste into streams that yield lower life-cycle costs. Some of the technologies being developed by the Tank Focus Area (TFA) to process these wastes are described. These technologies fall roughly into three areas: (1) solid/liquid separation (SLS), (2) sludge pretreatment, and (3) supernate pretreatment.

McGinnis, C.P.; Welch, T.D. [Oak Ridge National Lab., TN (United States); Manke, K.L. [Pacific Northwest National Lab., Richland, WA (United States)

1997-03-01

270

ESPERE Project: Focus on Agronomy  

NASA Astrophysics Data System (ADS)

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.

de La Osa, J.; Iglesias, A.

2003-04-01

271

Non-focusing active warhead  

DOEpatents

A non-nuclear, non-focusing, active warhead that comprises a high explosive charge contained within a casing of reactive metal is disclosed. 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. 4 figs.

Hornig, H.C.

1998-12-22

272

Focusing X-Ray Telescopes  

NASA Technical Reports Server (NTRS)

During the half-century history of x-ray astronomy, focusing x-ray telescopes, through increased effective area and finer angular resolution, have improved sensitivity by 8 orders of magnitude. Here, we review previous and current x-ray-telescope missions. Next, we describe the planned next-generation x-ray-astronomy facility, the International X-ray Observatory (IXO). We conclude with an overview of a concept for the next next-generation facility, Generation X. Its scientific objectives will require very large areas (about 10,000 sq m) of highly-nested, lightweight grazing-incidence mirrors, with exceptional (about 0.1-arcsec) resolution. Achieving this angular resolution with lightweight mirrors will likely require on-orbit adjustment of alignment and figure.

O'Dell, Stephen; Brissenden, Roger; Davis, William; Elsner, Ronald; Elvis, Martin; Freeman, Mark; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhall; Jerlus, Diab; Juda, Michael; Kolodziejczak, Jeffrey; Murray, Stephen; Petre, Robert; Podgorski, William; Ramsey, Brian; Reid, Paul; Saha, Timo; Wolk, Scott; Troller-McKinstry, Susan; Weisskopf, Martin; Wilke, Rudeger; Zhang, William

2010-01-01

273

Aerosol beam-focus laser-induced plasma spectrometer device  

DOEpatents

An apparatus for detecting elements in an aerosol includes an aerosol beam focuser for concentrating aerosol into an aerosol beam; a laser for directing a laser beam into the aerosol beam to form a plasma; a detection device that detects a wavelength of a light emission caused by the formation of the plasma. The detection device can be a spectrometer having at least one grating and a gated intensified charge-coupled device. The apparatus may also include a processor that correlates the wavelength of the light emission caused by the formation of the plasma with an identity of an element that corresponds to the wavelength. Furthermore, the apparatus can also include an aerosol generator for forming an aerosol beam from bulk materials. A method for detecting elements in an aerosol is also disclosed.

Cheng, Meng-Dawn (Oak Ridge, TN)

2002-01-01

274

RESEARCH PAPER Diamagnetic particle focusing using ferromicrofluidics  

E-print Network

RESEARCH PAPER Diamagnetic particle focusing using ferromicrofluidics with a single magnet Litao particle stream flowing near the bottom channel wall. Such three- dimensional diamagnetic particle focusing

Xuan, Xiangchun "Schwann"

275

Status of Dark Matter Detection  

E-print Network

The detection of dark matter has made great progresses in recent years. We give a brief review on the status and progress in dark matter detection, including the progresses in direct detection, collider detection at LHC and focus on the indirect detection. The results from PAMELA, ATIC, Fermi-LAT and relevant studies on these results are introduced. Then we give the progress on indirect detection of gamma rays from Fermi-LAT and ground based Cerenkov telescopes. Finally the detection of neutrinos and constraints on the nature of dark matter are reviewed briefly.

Xiao-Jun Bi; Peng-Fei Yin; Qiang Yuan

2014-09-16

276

Focus on quantum Einstein gravity Focus on quantum Einstein gravity  

NASA Astrophysics Data System (ADS)

The gravitational asymptotic safety program summarizes the attempts to construct a consistent and predictive quantum theory of gravity within Wilson's generalized framework of renormalization. Its key ingredient is a non-Gaussian fixed point of the renormalization group flow which controls the behavior of the theory at trans-Planckian energies and renders gravity safe from unphysical divergences. Provided that the fixed point comes with a finite number of ultraviolet-attractive (relevant) directions, this construction gives rise to a consistent quantum field theory which is as predictive as an ordinary, perturbatively renormalizable one. This opens up the exciting possibility of establishing quantum Einstein gravity as a fundamental theory of gravity, without introducing supersymmetry or extra dimensions, and solely based on quantization techniques that are known to work well for the other fundamental forces of nature. While the idea of gravity being asymptotically safe was proposed by Steven Weinberg more than 30 years ago [1], the technical tools for investigating this scenario only emerged during the last decade. Here a key role is played by the exact functional renormalization group equation for gravity, which allows the construction of non-perturbative approximate solutions for the RG-flow of the gravitational couplings. Most remarkably, all solutions constructed to date exhibit a suitable non-Gaussian fixed point, lending strong support to the asymptotic safety conjecture. Moreover, the functional renormalization group also provides indications that the central idea of a non-Gaussian fixed point providing a safe ultraviolet completion also carries over to more realistic scenarios where gravity is coupled to a suitable matter sector like the standard model. These theoretical successes also triggered a wealth of studies focusing on the consequences of asymptotic safety in a wide range of phenomenological applications covering the physics of black holes, early time cosmology and the big bang, as well as TeV-scale gravity models testable at the Large Hadron Collider. On different grounds, Monte-Carlo studies of the gravitational partition function based on the discrete causal dynamical triangulations approach provide an a priori independent avenue towards unveiling the non-perturbative features of gravity. As a highlight, detailed simulations established that the phase diagram underlying causal dynamical triangulations contains a phase where the triangulations naturally give rise to four-dimensional, macroscopic universes. Moreover, there are indications for a second-order phase transition that naturally forms the discrete analog of the non-Gaussian fixed point seen in the continuum computations. Thus there is a good chance that the discrete and continuum computations will converge to the same fundamental physics. This focus issue collects a series of papers that outline the current frontiers of the gravitational asymptotic safety program. We hope that readers get an impression of the depth and variety of this research area as well as our excitement about the new and ongoing developments. References [1] Weinberg S 1979 General Relativity, an Einstein Centenary Survey ed S W Hawking and W Israel (Cambridge: Cambridge University Press)

Ambjorn, Jan; Reuter, Martin; Saueressig, Frank

2012-09-01

277

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

PubMed

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

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

1994-01-01

278

Antipodal focusing of seismic waves observed with the USArray  

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

279

Hydrodynamic focusing of conducting fluids for conductivity-based biosensors.  

PubMed

Hydrodynamic focusing of a conducting fluid by a non-conducting fluid to form a constricted current path between two sensing electrodes is implemented in order to enhance the sensitivity of a 4-electrode conductance-based biosensor. The sensor has a simple two-inlet T-junction design and performs four-point conductivity measurements to detect particles immobilized between the sensing electrode pair. Computational simulations conducted in conjunction with experimental flow studies using confocal microscopy show that a flat profile for the focused layer is dependent on the Reynolds number for the chosen flow parameters. The results also indicate that a flat focused layer is desirable for both increased sensitivity as well as surface-binding efficiency. Proof of concept for conductance measurements in a hydrodynamically focused conducting fluid was demonstrated with entrapped magnetic beads. PMID:19932019

Nasir, Mansoor; Ateya, Daniel A; Burk, Diana; Golden, Joel P; Ligler, Frances S

2010-02-15

280

Focused electron beam induced deposition: A perspective  

PubMed Central

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

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

2012-01-01

281

Focus groups reveal consumer ambivalence.  

PubMed

According to qualitative research, Salvadoreans are ambivalent about the use of contraceptives. Since complete responsibility for management of the CSM project was accepted by the Association Demografica Salvadorena (ADS), the agency which operates the contraceptive social marketing project in El Salvador, in November 1980, the need for decisions in such areas as product price increases, introduction of new condom brands, promotion of the vaginal foaming tablet, and assessment of product sales performance had arisen. The ICSMP funded market research, completed during 1983, was intended to provide the data on which such decisions by ADS could be based. The qualitative research involved 8 focus groups, comprised of men and women, aged 18-45, contraceptive users and nonusers, from the middle and lower socioeconomic strata of the city of San Salvador and other suburban areas. In each group a moderator led discussion of family planning and probed respondents for specific attitudes, knowledge, and behavior regarding the use of contraceptives. To assess attitudes at a more emotional level, moderators asked respondents to "draw" their ideas on certain issues. A marked discrepancy was revealed between respondents' intellectual responses to the issues raised in group discussion, as opposed to their feelings expressed in the drawings. Intellectually, participants responded very positively to family planning practice, but when they were asked to draw their perceptions, ambivalent feelings emerged. Drawings of both the user and the nonuser convey primarily negative aspects for either choice. The user is tense and moody toward her children; the nonuser loses her attractiveness and "dies." Figures also show drawings of some of the attitudes of single and married male participants. 1 drawing shows an incomplete and a complete circle, symbolizing a sterilized man (incomplete) and a nonsterilized man (complete). Another picture depicts a chained man who has lost his freedom (sterilized) versus a world of abundance and strength enjoyed by a nonsterilized man. The results of the projective drawings are only a small part of the total market research effort in El Salvador, yet they seem to indicate that the development of a CSM project communications strategy is critically important to product sales and continued product use. New advertising messages will need to be carefully tested and much communication expertise will be required to develop a message that will contribute to resolving consumer ambivalences toward product use. PMID:12279792

1983-01-01

282

Focus Issue: Building Signaling Connections  

NSDL National Science Digital Library

The STKE Connections Maps database continues to flourish, with new canonical and specific pathways being added throughout the year, and the existing pathways being updated continuously. This year's Special Issue, published in conjunction with a series of Viewpoints in Science, highlights new canonical pathways in immunology [Interleukin 4 (IL-4) and IL-13 Pathways by Kelly-Welch et al. and the Toll-Like Receptor (TLR) Pathway by Barton and Medzhitov], as well as new canonical and specific pathways in neurobiology (Circadian Rhythm Pathways by Van Gelder and Granule Cell Survival Pathway by Leuillet et al.). In addition, the seven transmembrane family of receptors, which most often couple to heterotrimeric guanine nucleotide-binding proteins (G proteins) and are therefore best known as G protein-coupled receptors (GPCRs), are represented with new pathways and Viewpoints. These new pathways, which complement the existing Gαi, Gαs, Gαq, Gα12, and Gα13 seven transmembrane receptor signaling pathways by Iyengar and colleagues, include examples of G protein-independent signaling, as well as signaling pathways mediated by G proteins. Both a canonical and a specific pathway by Kimmel and Parent focus attention on the persistence of signaling from seven transmembrane adenosine 3′,5′ monophosphate (cAMP) receptors even in Dictyostelium discoidium deficient in various G protein genes. Kimmel and Parent also provide a pathway describing the D. discoidium G protein-mediated chemotactic response to cAMP. The seven transmembrane receptor signaling pathways also include a new pathway for Wnt signaling that describes emerging evidence that certain isoforms of Frizzled receptors--best known for their G protein-independent regulation of β-catenin stability and activation of β-catenin as a transcriptional regulator in response to Wnt--can also signal through G proteins to regulate intracellular calcium and guanosine 3′,5′-monophosphate (cGMP) concentrations. Finally, adrenoreceptor signaling, which has important clinical implications in heart disease, is featured in canonical and myocyte-specific pathways by Xiang and Kobilka.

Nancy R. Gough (American Association for the Advancement of Science;Managing Editor of Science's STKE REV); Elizabeth M. Adler (American Association for the Advancement of Science;Associate Editor of Science's STKE REV); L. Bryan Ray (American Association for the Advancement of Science;Editor of Science's STKE and Senior Editor of Science REV)

2003-06-10

283

EDITORIAL: Focus on Plasma Medicine  

NASA Astrophysics Data System (ADS)

'Plasma Healthcare' is an emerging interdisciplinary research topic of rapidly growing importance, exploring considerable opportunities at the interface of plasma physics, chemistry and engineering with life sciences. Some of the scientific discoveries reported so far have already demonstrated clear benefits for healthcare in areas of medicine, food safety, environmental hygiene, and cosmetics. Examples include ongoing studies of prion inactivation, chronic wound treatment and plasma-mediated cancer therapy. Current research ranges from basic physical processes, plasma chemical design, to the interaction of plasmas with (i) eukaryotic (mammalian) cells; (ii) prokaryotic (bacteria) cells, viruses, spores and fungi; (iii) DNA, lipids, proteins and cell membranes; and (iv) living human, animal and plant tissues in the presence of biofluids. Of diverse interests in this new field is the need for hospital disinfection, in particular with respect to the alarming increase in bacterial resistance to antibiotics, the concomitant needs in private practices, nursing homes etc, the applications in personal hygiene—and the enticing possibility to 'design' plasmas as possible pharmaceutical products, employing ionic as well as molecular agents for medical treatment. The 'delivery' of the reactive plasma agents occurs at the gaseous level, which means that there is no need for a carrier medium and access to the treatment surface is optimal. This focus issue provides a close look at the current state of the art in Plasma Medicine with a number of forefront research articles as well as an introductory review. Focus on Plasma Medicine Contents Application of epifluorescence scanning for monitoring the efficacy of protein removal by RF gas-plasma decontamination Helen C Baxter, Patricia R Richardson, Gaynor A Campbell, Valeri I Kovalev, Robert Maier, James S Barton, Anita C Jones, Greg DeLarge, Mark Casey and Robert L Baxter Inactivation factors of spore-forming bacteria using low-pressure microwave plasmas in an N2 and O2 gas mixture M K Singh, A Ogino and M Nagatsu Degradation of adhesion molecules of G361 melanoma cells by a non-thermal atmospheric pressure microplasma H J Lee, C H Shon, Y S Kim, S Kim, G C Kim and M G Kong The acidification of lipid film surfaces by non-thermal DBD at atmospheric pressure in air A Helmke, D Hoffmeister, N Mertens, S Emmert, J Schuette and W Vioel Reduction and degradation of amyloid aggregates by a pulsed radio-frequency cold atmospheric plasma jet D L Bayliss, J L Walsh, G Shama, F Iza and M G Kong The effect of low-temperature plasma on bacteria as observed by repeated AFM imaging René Pompl, Ferdinand Jamitzky, Tetsuji Shimizu, Bernd Steffes, Wolfram Bunk, Hans-Ulrich Schmidt, Matthias Georgi, Katrin Ramrath, Wilhelm Stolz, Robert W Stark, Takuya Urayama, Shuitsu Fujii and Gregor Eugen Morfill Removal and sterilization of biofilms and planktonic bacteria by microwave-induced argon plasma at atmospheric pressure Mi Hee Lee, Bong Joo Park, Soo Chang Jin, Dohyun Kim, Inho Han, Jungsung Kim, Soon O Hyun, Kie-Hyung Chung and Jong-Chul Park Cell permeabilization using a non-thermal plasma M Leduc, D Guay, R L Leask and S Coulombe Physical and biological mechanisms of direct plasma interaction with living tissue Danil Dobrynin, Gregory Fridman, Gary Friedman and Alexander Fridman Nosocomial infections-a new approach towards preventive medicine using plasmas G E Morfill, T Shimizu, B Steffes and H-U Schmidt Generation and transport mechanisms of chemical species by a post-discharge flow for inactivation of bacteria Takehiko Sato, Shiroh Ochiai and Takuya Urayama Low pressure plasma discharges for the sterilization and decontamination of surfaces F Rossi, O Kylián, H Rauscher, M Hasiwa and D Gilliland Contribution of a portable air plasma torch to rapid blood coagulation as a method of preventing bleeding S P Kuo, O Tarasenko, J Chang, S Popovic, C Y Chen, H W Fan, A Scott, M Lahiani, P Alusta, J D Drake and M Nikolic A two-dimensional cold atmospheric plasma jet array for uniform treatment of large-area

Morfill, G. E.; Kong, M. G.; Zimmermann, J. L.

2009-11-01

284

AXAF VETA-I mirror ring focus measurements  

NASA Technical Reports Server (NTRS)

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.

Tananbaum, H. D.; Zhao, P.

1994-01-01

285

Uniform-density, spherical electron focus  

NASA Astrophysics Data System (ADS)

An equilibrium electron distribution is exhibited which forms a uniform electron density focus within a spherical system. Such a focus may be used to form a spherical, harmonic well for ion focusing as previously discussed. A self-consistent density and space-charge potential are calculated and the optimum focus radius is determined. Nonideal effects on electron and ion motion in the resulting electrostatic well are briefly discussed and strategies for their minimization are derived.

Barnes, D. C.

1999-12-01

286

Focus Groups as an Evaluation Tool.  

ERIC Educational Resources Information Center

This abstract and outline for a workshop explore the use of focus groups in evaluation. Cerritos College in Norwalk (California) conducted a series of focus groups to evaluate a new matriculation program. A focus group is a technique often used in marketing research to explore a specific topic. It is a group interview conducted in a casual setting…

Creason, Paul

287

Introduction to the Focused Issue on Entrepreneurship  

Microsoft Academic Search

This article is an introduction to the focused issue on entrepreneurship. It provides motivation for greater scholarly investigation of the phenomenon of entrepreneurship, explains the evolution of the focused issue, offers an overview of the seven papers in the issue, and offers the editor's thoughts on the relationship of the papers in the focused issue to research on entrepreneurship in

Scott Shane

2006-01-01

288

Focusing surface waves using an axicon  

Microsoft Academic Search

Axicons are generators of waves which focus on a line. They are used in various imaging and nondestructive testing applications as bulk wave focusing devices with a very long depth of focus. In this letter, a new type of conical axicon is introduced and it is shown that this axicon, immersed in a liquid, insonifying a plane solid surface can

Hayrettin Köymen; Abdullah Atalar

1985-01-01

289

Optofluidic variable-focus lenses for light manipulation.  

PubMed

This paper presents a planar optofluidic lens for light manipulation utilizing a combination of optofluidic biconvex lens with micromixer. Three light manipulation techniques including tunable optical diverging, collimating and focusing are realized by altering the refractive index of the optofluidic variable-focus lenses formed by solid polydimethylsiloxane (PDMS) walls and tunable liquid lens body. The optical power from the laser input can be increased or decreased with the tuning of the variable-focus lenses' refractive indexes. The optical power adjustment capabilities are demonstrated and characterized. The combinations of benefits of all lens' optical manipulation capabilities, greater mechanical stability, significant increase of optofluidic device's life time and seamless integration with other lab-on-a-chip functionalities provide a promising and versatile optofluidic compartment to integrate with lab-on-a-chip excitation and sensing applications. Optofluidic lens-including system for tunable fluorescence sensing is demonstrated showing 186% increase in detected fluorescence intensity. PMID:22885654

Seow, Y C; Lim, S P; Lee, H P

2012-10-01

290

Quantitative results from the focusing schlieren technique  

NASA Technical Reports Server (NTRS)

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.

Cook, S. P.; Chokani, Ndaona

1993-01-01

291

Intelligent agents for intrusion detection  

Microsoft Academic Search

The paper focuses on intrusion detection and countermeasures with respect to widely-used operating systems and networks. The design and architecture of an intrusion detection system built from distributed agents is proposed to implement an intelligent system on which data mining can be performed to provide global, temporal views of an entire networked system. A starting point for agent intelligence in

Guy G. Helmer; Johnny S. K. Wong; Vasant Honavar; Les Miller

1998-01-01

292

Focus and dose characterization of immersion photoclusters  

NASA Astrophysics Data System (ADS)

The process window for state of the art chip manufacturing continues to decrease, driven by higher NA exposure tools and lower k1 values. The benefits of immersion lithography for Depth of Focus (DoF) are well known. Yet even with this immersion boost, NA=1.35 tools can push DoF into sub-100nm territory. In addition, immersion processes are subject to new sources of dose and focus variation. In order to realize the full potential of immersion lithography, it is necessary to characterize, understand and attack all sources of process variation. Previous work has established our dose/focus metrology capability1, in which we expose Process Monitor Grating (PMG) targets with high sensitivity to focus, measure the PMGs using scatterometry, and use the Ausschnitt dose/focus deconvolution approach to determine focus errors to within a few nm and dose errors to within 0.1%. In this paper, we concentrate on applying this capability to the detailed measurements of immersion photoclusters utilizing ASML exposure tools. Results will include: • comparison of Twinscan 1700i and 1900i focus capability • effectiveness of the Reticle Shape Correction (RSC) for non-flat reticles • visualization of non-flat wafer chucks, tilted image planes, and other systematic focus error components • tracking of tool trends over time, using automated monitor wafer flows The highly systematic nature of the observed focus errors suggest potential for future improvements in focus capability.

Brunner, T. A.; Corliss, D.; Wiltshire, T.; Ausschnitt, C. P.

2009-03-01

293

Characterization of optical microring ultrasound detector by using a high frequency focused photoacoustic transmitter  

PubMed Central

We characterize a response of optical microring resonator to high frequency focused ultrasound. To properly evaluate the response over high frequency and broadband spectrum, we use a photoacoustic concave transmitter generating and subsequently focusing the ultrasound. A detected focused profile reveals two types of spatial peaks due to the special ring-shaped detector geometry interacting with the high frequency focused ultrasound. Spectral analysis shows that those peaks are contributed by the main and the side lobes of focused ultrasound, respectively. Experimental focal widths agree with theoretical values within ±2 ?m error, which can be attributed to the narrow width of waveguide. PMID:19902003

Won Baac, Hyoung; Ling, Tao; Huang, Sheng-Wen; Ashkenazi, Shai; Guo, L. Jay

2009-01-01

294

Subwavelength Focusing Technique Using a Plasmonic Lens  

NASA Astrophysics Data System (ADS)

A plasmonic lens (PL) is the one of the promising photonic devices utilizing the surface plasmon wave. For example, the surface plasmon wave can be focused by the use of a PL structure consisting of only a single annular subwavelength slit milled into a metal thin film on a glass substrate. We fabricated a PL structure for 532 nm wavelength and evaluated its beam focusing characteristics using a near-field scanning microscope (NSOM). We confirmed that a plasmonic lens with only several micron size can produce a subwavelength focusing spot not only in the near-field, but also in the quasi far-field region. Moreover, we found that the PL generates a tightly focused beam through several microns with a low divergence angle, keeping a high intensity level. These unique beam focusing characteristics with adequate long working distance and depth of focus will offer many applications, such as optical memories, nanolithography, and biochemical sensing.

Takeda, Minoru; Nakatani, Suguru

2012-08-01

295

Non-scanning x-ray backscattering inspection systems based on x-ray focusing  

Microsoft Academic Search

Non-invasive real-time detection and identification of high explosives and improvised explosive devices, illicit materials hidden inside suitcases, vehicles, containers or behind metal and non-metal walls become critically important for safety and security worldwide. In this paper we will discuss non-scanning, portable real-time detection X-ray backscattering system based on novel Lobster-Eye X-ray focusing optics, which focuses backscatter photons from fully obscured

V. Grubsky; M. Gertsenshteyn; T. Jannson; G. Savant

2007-01-01

296

Needs of Non Energy-Focused Contractors  

SciTech Connect

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.

Liaukus, C.

2012-12-01

297

Mood-Induced Self-Focused Attention  

Microsoft Academic Search

The influence of mood on self-focused attention was explored in 2 experiments involving the induction of moods in the laboratory. Experiment 1 tested the hypothesis that mood states, whether pleasant or unpleasant, induce self-focused attention. This hypothesis was supported using a sentence completion task as the measure of self-focus. Experiment 2 replicated Experiment 1 results using a measure of self-complexity

Peter Salovey

1992-01-01

298

Low voltage operation of plasma focus.  

PubMed

Plasma foci of compact sizes and operating with low energies (from tens of joules to few hundred joules) have found application in recent years and have attracted plasma-physics scientists and engineers for research in this direction. We are presenting a low energy and miniature plasma focus which operates from a capacitor bank of 8.4 muF capacity, charged at 4.2-4.3 kV and delivering approximately 52 kA peak current at approximately 60 nH calculated circuit inductance. The total circuit inductance includes the plasma focus inductance. The reported plasma focus operates at the lowest voltage among all reported plasma foci so far. Moreover the cost of capacitor bank used for plasma focus is nearly 20 U.S. dollars making it very cheap. At low voltage operation of plasma focus, the initial breakdown mechanism becomes important for operation of plasma focus. The quartz glass tube is used as insulator and breakdown initiation is done on its surface. The total energy of the plasma focus is approximately 75 J. The plasma focus system is made compact and the switching of capacitor bank energy is done by manual operating switch. The focus is operated with hydrogen and deuterium filled at 1-2 mbar. PMID:20815602

Shukla, Rohit; Sharma, S K; Banerjee, P; Das, R; Deb, P; Prabahar, T; Das, B K; Adhikary, B; Shyam, A

2010-08-01

299

Detective científica  

NASA Video Gallery

La NASA posee muchos detectives que buscan pistas para resolver un misterio como la "detective científica" Monsi Roman. Se asegura de que el agua y el aire a bordo de la Estación Espacial Internaci...

300

Seismic Migration For Sar Focusing: Interferometrical Applications  

Microsoft Academic Search

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

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

1990-01-01

301

Focusing One's Microscope By Daniel Pauly  

E-print Network

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

Pauly, Daniel

302

How I Learned to Conduct Focus Groups  

ERIC Educational Resources Information Center

The use of focus groups may provide researchers with important insights into research questions via participant discussion and interaction. As a human services practitioner and researcher, I became interested in learning how to conduct focus groups in order to apply these steps to my research and gain valuable insights about the human experience…

Del Rio-Roberts, Maribel

2011-01-01

303

Techniques for Analyzing Focus Group Data  

Microsoft Academic Search

Focus groups are widely used in the field of public health as a quick, low-cost means of obtaining information from selected groups in the target population for programmatic purposes. Much has been written about techniques for conducting focus groups, but there is limited practical information on systematic analysis of the results. The current article outlines three methods of recording information

Jane T. Bertrand; Judith E. Brown; Victoria M. Ward

1992-01-01

304

Identifying Information Focuses in Listening Comprehension  

ERIC Educational Resources Information Center

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…

Zhang, Hong-yan

2011-01-01

305

Results from the scaled final focus experiment  

Microsoft Academic Search

Vacuum ballistic focusing is the straightforward method to obtain a heavy-ion beam spot size necessary to drive an inertial confinement fusion target. The beam is first expanded then focused to obtain the desired convergence angles at the exit of the last element. This is done in an attempt to achieve a focal spot size in which emittance is the limiting

S. A. MacLaren; M. de Hoon; A. Faltens; W. Ghiorso; P. Seidl

2001-01-01

306

Results from the Scaled Final Focus Experiment.  

National Technical Information Service (NTIS)

Vacuum ballistic focusing is the straightforward method to obtain a heavy ion beam spot size necessary to drive an inertial confinement fusion target. The beam is first expanded then focused to obtain the desired convergence angles at the exit of the last...

S. A. MacLaren, M. J. L. de Hoon, A. Falten, W. Ghiorso, P. Seidl

2000-01-01

307

Results from the Scaled Final Focus Experiment  

Microsoft Academic Search

Vacuum ballistic focusing is the straightforward method to obtain a heavy ion beam spot size necessary to drive an inertial confinement fusion target. The beam is first expanded then focused to obtain the desired convergence angles at the exit of the last element. This is done in an attempt to achieve a focal spot size in which emittance is the

S. A. MacLaren; M. J. L. de Hoon; A. Falten; W. Ghiorso; P. Seidl

2000-01-01

308

FEMP/NTDP Technology Focus New Technology  

E-print Network

FEMP/NTDP Technology Focus New Technology Demonstration Program Technology Focus FEMPFederal Energy Management Program Trends in Energy Management Technology: BCS Integration Technologies ­ Open Communications into a complete EMCIS. The first article [1] covered enabling technologies for emerging energy management systems

309

Conducting the Computer-Mediated Focus Group.  

ERIC Educational Resources Information Center

The growing popularity of focus group measurements can be traced to any one of four factors: (1) the economics associated with focus groups; (2) the speed at which data can now be collected; (3) the need to understand customer motivations; and (4) the desire to improve subsequent qualitative research activities and programs. Market researchers are…

Saban, Kenneth A.

310

Focusing polychromatic light through strongly scattering media  

E-print Network

the relationship between optimized focus intensity and initial far-field speckle contrast. Optimization. Mosk, "Phase control algorithms for focusing light through turbid media," Opt. Commun. 281(11), 3071 at visible wavelengths," Nat Commun 3, 889 (2012). 16. J. W. Goodman, Speckle Phenomena in Optics (Roberts

311

Becoming an Emotionally Focused Couple Therapist  

Microsoft Academic Search

This article provides a beginning exploration of the pro cess involved in becoming an emotionally focused therapist. The under lying assumptions of emotionally focused therapy (EFT) are identified and examined in relation to how the theory affects therapeutic practice with couples and families. A number of themes are outlined including fit between the therapist and EFT, the challenges of working

Gail Palmer; Susan Johnsonm

2002-01-01

312

Inclusive Focus Particles in English and Korean  

ERIC Educational Resources Information Center

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…

Kang, Sang-gu

2011-01-01

313

Correctional Health Curriculum Enhancement Through Focus Groups  

Microsoft Academic Search

Background: Little has been published describing curricular experiences in correctional health (CH). Purposes: Our goal is to articulate a curriculum cognizant of the special needs of the correctional health care worker. Methods: We conducted focus groups with nurses, nurse practitioners, physician assistants, and physicians focused on content crucial to prepare competent medical professionals committed to careers in correctional health. Results:

Heather-Lyn Haley; Warren Ferguson; Arthur Brewer; Janet Hale

2009-01-01

314

Final focus systems for linear colliders  

SciTech Connect

The final focus system of a linear collider must perform two primary functions, it must focus the two opposing beams so that their transverse dimensions at the interaction point are small enough to yield acceptable luminosity, and it must steer the beams together to maintain collisions. In addition, the final focus system must transport the outgoing beams to a location where they can be recycled or safely dumped. Elementary optical considerations for linear collider final focus systems are discussed, followed by chromatic aberrations. The design of the final focus system of the SLAC Linear Collider (SLC) is described. Tuning and diagnostics and steering to collision are discussed. Most of the examples illustrating the concepts covered are drawn from the SLC, but the principles and conclusions are said to be generally applicable to other linear collider designs as well. 26 refs., 17 figs. (LEW)

Erickson, R.A.

1987-11-01

315

Attentional Focusing Instructions and Force Production  

PubMed Central

Research progress assessing the role of attentional focusing instructions on skill acquisition and performance has lead researchers to apply this approach to force production tasks. Initial converging evidence indicates that force production tasks are sensitive to verbal instruction; externally focused instructions (onto movement outcomes, or onto the object force is being exerted against) are shown to be more beneficial than internally focused instructions (focusing attention onto the movements being executed). These benefits are observed for maximal and accurate force production, as well as the maintenance of force production in prolonged tasks. A range of mechanisms are identified supporting the proposal that an external focus promotes movement efficiency in line with energy and effort conservation. Future research is required to assess how this developing body of work interacts with the broader understanding of psychological and physiological factors implicated in the effective production, maintenance, and limitation of maximal or sub-maximal forces. PMID:21833266

Marchant, David C.

2010-01-01

316

Detection of a novel mechanism of acousto-optic modulation of incoherent light.  

PubMed

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

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

2014-01-01

317

Tanks Focus Area annual report FY2000  

SciTech Connect

The U.S. Department of Energy (DOE) continues to face a major radioactive waste tank remediation effort with tanks containing hazardous and radioactive waste resulting from the production of nuclear materials. With some 90 million gallons of waste in the form of solid, sludge, liquid, and gas stored in 287 tanks across the DOE complex, containing approximately 650 million curies, radioactive waste storage tank remediation is the nation's highest cleanup priority. Differing waste types and unique technical issues require specialized science and technology to achieve tank cleanup in an environmentally acceptable manner. Some of the waste has been stored for over 50 years in tanks that have exceeded their design lives. The challenge is to characterize and maintain these contents in a safe condition and continue to remediate and close each tank to minimize the risks of waste migration and exposure to workers, the public, and the environment. In 1994, the DOE's Office of Environmental Management (EM) created a group of integrated, multiorganizational teams focusing on specific areas of the EM cleanup mission. These teams have evolved into five focus areas managed within EM's Office of Science and Technology (OST): Tanks Focus Area (TFA); Deactivation and Decommissioning Focus Area; Nuclear Materials Focus Area; Subsurface Contaminants Focus Area; and Transuranic and Mixed Waste Focus Area.

None

2000-12-01

318

Deep-Focusing Time-Distance Helioseismology  

NASA Technical Reports Server (NTRS)

Much progress has been made by measuring the travel times of solar acoustic waves from a central surface location to points at equal arc distance away. Depth information is obtained from the range of arc distances examined, with the larger distances revealing the deeper layers. This method we will call surface-focusing, as the common point, or focus, is at the surface. To obtain a clearer picture of the subsurface region, it would, no doubt, be better to focus on points below the surface. Our first attempt to do this used the ray theory to pick surface location pairs that would focus on a particular subsurface point. This is not the ideal procedure, as Born approximation kernels suggest that this focus should have zero sensitivity to sound speed inhomogeneities. However, the sensitivity is concentrated below the surface in a much better way than the old surface-focusing method, and so we expect the deep-focusing method to be more sensitive. A large sunspot group was studied by both methods. Inversions based on both methods will be compared.

Duvall, T. L., Jr.; Jensen, J. M.; Kosovichev, A. G.; Birch, A. C.; Fisher, Richard R. (Technical Monitor)

2001-01-01

319

Laser focus compensating sensing and imaging device  

DOEpatents

A laser focus compensating sensing and imaging device permits the focus of a single focal point of different frequency laser beams emanating from the same source point. In particular it allows the focusing of laser beam originating from the same laser device but having differing intensities so that a low intensity beam will not convert to a higher frequency when passing through a conversion crystal associated with the laser generating device. The laser focus compensating sensing and imaging device uses a Cassegrain system to fold the lower frequency, low intensity beam back upon itself so that it will focus at the same focal point as a high intensity beam. An angular tilt compensating lens is mounted about the secondary mirror of the Cassegrain system to assist in alignment. In addition cameras or CCD's are mounted with the primary mirror to sense the focused image. A convex lens is positioned co-axial with the Cassegrain system on the side of the primary mirror distal of the secondary for use in aligning a target with the laser beam. A first alternate embodiment includes a Cassegrain system using a series of shutters and an internally mounted dichroic mirror. A second alternate embodiment uses two laser focus compensating sensing and imaging devices for aligning a moving tool with a work piece.

Vann, C.S.

1993-08-31

320

Line-focus concentrating collector program  

NASA Astrophysics Data System (ADS)

The Line-Focus Concentrating Collector Program has emphasized the development and dissemination of concentrating solar technology in which the reflected sunlight is focused onto a linear or line receiver. Although a number of different types of line-focus concentrators were developed, the parabolic trough has gained the widest acceptance and utilization within the industrial and applications sectors. The trough is best applied for application scenarios which require temperatures between 140 and 600 F. Another concept, the bowl, is investigated for applications which may require temperatures in the range between 600 and 1200 F. Current technology emphases are upon the reduction of system installation cost and the implementation of production oriented engineering.

Dugan, V. L.

1980-05-01

321

Modeling techniques for target detection  

NASA Astrophysics Data System (ADS)

To better study hyperspectral imaging sensors and remote sensing system performance, different parts of the remote sensing system can be modeled. Here, a scientific overview of recent modeling techniques is presented to come up with an appropriate approach for modeling of a target detection system. In particular, this study focuses on the development in modeling of scene, sensors, and processing algorithms. Moreover, the parallelization of the detection methods is emphasized for which the process of target detection accelerates. In conclusion, an appropriate model to evaluate a target detection system can be a hybrid model in which hyperspectral sensors, radars, and local sensors have been modeled.

Attapattu, Jeevake; Sharifahmadian, Ershad; Latifi, Shahram

2014-06-01

322

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

NASA Astrophysics Data System (ADS)

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

Ajdari, Armand; Stone, Howard A.

2009-07-01

323

Micro free-flow isoelectric focusing  

E-print Network

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 ...

Albrecht, Jacob William

2008-01-01

324

Focusing on ADHD - Attention Deficit Hyperactivity Disorder  

MedlinePLUS

... review our exit disclaimer . Subscribe Focusing on ADHD Attention Deficit Hyperactivity Disorder Most children get restless, rowdy, or distracted at ... might be signs of a developmental disorder called attention deficit hyperactivity disorder, or ADHD. ADHD is a common brain condition ...

325

Apparatus for focusing flowing gas streams  

DOEpatents

Apparatus for focusing gas streams. The principle of hydrodynamic focusing is applied to flowing gas streams in order to provide sample concentration for improved photon and sample utilization in resonance ionization mass spectrometric analysis. In a concentric nozzle system, gas samples introduced from the inner nozzle into the converging section of the outer nozzle are focused to streams 50-250-..mu..m in diameter. In some cases diameters of approximately 100-..mu..m are maintained over distances of several centimeters downstream from the exit orifice of the outer nozzle. The sheath gas employed has been observed to further provide a protective covering around the flowing gas sample, thereby isolating the flowing gas sample from possible unwanted reactions with nearby surfaces. A single nozzle variation of the apparatus for achieving hydrodynamic focusing of gas samples is also described.

Nogar, N.S.; Keller, R.A.

1985-05-20

326

Clinical Focus Identifying Residual Speech Sound  

E-print Network

AJSLP Clinical Focus Identifying Residual Speech Sound Disorders in Bilingual Children: A Japanese speech sound disorders (SSDs) in bilinguals by distinguishing speech patterns associated with second understanding of a client's strengths and needs. Key Words: bilingualism, articulation, residual speech sound

327

Focusing Internet Searches for World Music Resources  

ERIC Educational Resources Information Center

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.

Mishra, Jennifer

2004-01-01

328

FOCUS > National Prominence LSU's National Flagship Agenda  

E-print Network

, and shows no sign of stopping. Having witnessed many of yesterday's possi- bilities become tangible;2 FOCUS > A Shared Vision An aerial view of Marsh Island Refuge and Game Preserve off the Louisiana coast

329

Synthetic Aperture Focusing Technique for the Ultrasonic Evaluation of Friction Stir Welds  

NASA Astrophysics Data System (ADS)

An ultrasonic technique using numerical focusing and processing is presented in this paper for the detection of different types of flaws in friction stir welds (FSW). The data is acquired using immersion ultrasonic technique or laser ultrasonics, while the Synthetic Aperture Focusing Technique (SAFT) is used for numerical focusing. Measurements on the top and far sides of the weld for both lap and butt joints of thin aluminum sheets are investigated. Discontinuities such as wormholes, hooking, lack of penetration and voids are found to be easily detected. The limit of detectability and a comparison with mechanical properties are discussed. Also, the detection of joint line remnants or kissing bonds due to entrapped oxide layers seems possible in lap joint structures using high frequency laser-ultrasonics.

Lévesque, D.; Dubourg, L.; Mandache, C.; Kruger, S. E.; Lord, M.; Merati, A.; Jahazi, M.; Monchalin, J.-P.

2008-02-01

330

Regulatory focus and attitudes to migrants  

Microsoft Academic Search

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

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

2010-01-01

331

Superconducting quadrupoles for the SLC final focus  

SciTech Connect

The final focus system of the SLC will be upgraded by replacing the final quadrupoles with higher gradient superconducting magnets positioned closer to the interaction point. The parameters of the new system have been chosen to be compatible with the experimental detectors with a minimum of changes to other final focus components. These parameter choices are discussed along with the expected improvement in SLC performance.

Erickson, R.; Fieguth, T.; Murray, J.J.

1987-01-01

332

Focus Writer 1.3.5.2  

NSDL National Science Digital Library

In a media-rich environment with a wide range of entertainment on-demand, it can be hard to focus for more than a few minutes at a time. Focus Writer provides a simple, distraction-free writing environment. The program utilizes a hide-away interface that users access by moving their mouse to the edges of the screen, and it's quite helpful. This version is compatible with all operating systems, including Linux.

Gott, Graeme

2012-04-20

333

Focusing surface plasmons by a plasmonic lens  

NASA Astrophysics Data System (ADS)

Surface plasmons have been launched from free space optical beams (at an excitation wavelength of 700 nm) and focused in the plane using concentric curved gratings (or plasmonic lenses) etched into 30 nm-thick gold films. The performance of these devices was studied with numerical simulation and verified by near-field scanning optical microscopy experiments. These plasmonic lenses have been demonstrated to focus the launched surface plasmons effectively to a high intensity focal spot.

Vo, Thanh Phong; Maleki, Alireza; Downes, James E.; Coutts, David W.; Dawes, Judith M.

2014-09-01

334

How to focus a Cherenkov telescope  

E-print Network

Cherenkov telescopes image the Cherenkov emission from air showers. A priori, it is not obvious if the `best' images are achieved by measuring Cherenkov photon angles, i.e. focusing the telescope at infinity, or by considering the air shower as an object to be imaged, in which case one might focus the telescope on the central region of the shower. The issue is addressed using shower simulations.

Werner Hofmann

2001-01-03

335

Bringing a large computer network into FOCUS  

SciTech Connect

The development and implementation of the Facility for Operations Control and Utilization Statistics (FOCUS), a new centralized node in the Integrated Computing Network of the Los Alamos National Laboratory is described. FOCUS consists of production control, performance measurement, and network information subsystems. The software engineering practices on which the development was based are discussed, with emphasis on the application of those practices to network systems development.

Morse, N.R.; Thompson, J.L.

1982-01-01

336

Focused ranking in a vertical search engine  

Microsoft Academic Search

Since the debut of PageRank and HITS, hyperlink-induced Web document ranking has come a long way. The Web has become increasingly vast and topically diverse. Such vastness has led many into the area of topic-sensitive ranking and its variants. We address the high dimensionality of the Web by providing tools for focused search. A focused search engine is one which

Philip O'brien; Tony Abou-assaleh

2007-01-01

337

Focused Page Rank in Scientific Papers Ranking  

Microsoft Academic Search

We propose Focused Page Rank (FPR) algorithm adaptation for the problem of scientific papers ranking. FPR is based on the\\u000a Focused Surfer model, where the probability to follow the reference in a paper is proportional to its citation count. Evaluation\\u000a on Citeseer autonomous digital library content showed that proposed model is a tradeoff between traditional citation count\\u000a and basic Page

Mikalai Krapivin; Maurizio Marchese

2008-01-01

338

Depression and self-focused attention  

Microsoft Academic Search

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

Timothy W. Smith; Jeff Greenberg

1981-01-01

339

Focusing Characteristics of a Spiral Plasmonic Lens  

NASA Astrophysics Data System (ADS)

A plasmonic lens (PL) is one of the promising photonic devices utilizing the surface plasmon wave. The surface plasmon wave can be focused using a PL structure consisting of only a single annular subwavelength slit milled into a metal film on a glass substrate. Recently, we have evaluated the beam focusing characteristics of a PL for 532 nm wavelength, which consists of a circular slit aperture of 4 µm diameter, using near-field scanning optical microscopy (NSOM), and confirmed that subwavelength focusing was attained at the center axis of the PL in both the near-field and far-field regions. However, for a PL with a circular slit, finite-difference time-domain (FDTD) simulations show that the focusing of the surface plasmon induced electric field into a single solid spot at the center cannot be achieved using circularly or linearly polarized light owing to the destructive interference between counter propagating surface plasmon waves from opposite circle slit points. In this study, we designed and fabricated a new PL with a spiral slit for 405 nm wavelength to produce a single solid focal spot due to the constructive interference at the nominal center of the PL. We measured the focusing characteristics of the PL and attained a tightly focused beam with a subwavelength spot size (?330 nm) at 3.5 µm above the PL surface.

Takeda, Minoru; Okuda, Shinpei; Inoue, Tsutomu; Aizawa, Kento

2013-09-01

340

Results from the scaled final focus experiment  

NASA Astrophysics Data System (ADS)

Vacuum ballistic focusing is the straightforward method to obtain a heavy-ion beam spot size necessary to drive an inertial confinement fusion target. The beam is first expanded then focused to obtain the desired convergence angles at the exit of the last element. This is done in an attempt to achieve a focal spot size in which emittance is the limiting factor; however, aberrations and space charge will influence the spot radius. Proper scaling of particle energy, mass, beam current, beam emittance, and magnetic field replicates the dynamics of a full driver beam at the focus in a small laboratory experiment. By scaling the beam current to ˜100 A, 160 keV Cs + has been used to study experimentally a proposed driver design at one-tenth scale. Once a nominal focal spot is achieved, the magnet strengths are deliberately de-tuned to simulate the effect of an off-momentum slice of the beam. Additionally, several methods will be used to inject electrons into beam following the last focusing element in order to study the neutralization of space charge and its effect on the focus. Transverse phase space and beam current density measurements at various stages of the focus will be presented as well spot size measurements from the various trials. This data will be compared to the results of a PIC model of the experiment.

MacLaren, S. A.; de Hoon, M.; Faltens, A.; Ghiorso, W.; Seidl, P.

2001-05-01

341

Results from the Scaled Final Focus Experiment  

SciTech Connect

Vacuum ballistic focusing is the straightforward method to obtain a heavy ion beam spot size necessary to drive an inertial confinement fusion target. The beam is first expanded then focused to obtain the desired convergence angles at the exit of the last element. This is done in an attempt to achieve a focal spot size in which emittance is the limiting factor; however, aberrations and space charge will influence the spot radius. Proper scaling of particle energy, mass, beam current, beam emittance, and magnetic field replicates the dynamics of a full driver beam at the focus in a small laboratory experiment. By scaling the beam current to {approximately}100 {mu}A, 160 keV Cs+ has been used to study experimentally a proposed driver design at one-tenth scale. Once a nominal focal spot is achieved, the magnet strengths are deliberately de-tuned to simulate the effect of an off-momentum slice of the beam. Additionally, several methods will be used to inject electrons into beam following the last focusing element in order to study the neutralization of space charge and its effect on the focus. Transverse phase space and beam current density measurements at various stages of the focus will be presented as well spot size measurements from the various trials. This data will be compared to the results of a PIC model of the experiment.

MacLaren, S.A.; de Hoon, M.J.L.; Falten, A.; Ghiorso, W.; Seidl, P.

2000-09-15

342

Efficacy of Emotion-Focused and Problem-Focused Group Therapies for Women with Fertility Problems  

Microsoft Academic Search

Competing positions exist in the literature regarding whether problem-focused or emotion-focused coping is more useful when one confronts a chronic health-related problem. In this study, 29 infertile women, who on average had been attempting conception for almost 4 years, were assigned to six sessions of training in problem- or emotion-focused coping or to a no-treatment control condition. Problem-focused training produced

Debra A. McQueeney; Annette L. Stanton; Sandra Sigmon

1997-01-01

343

Abnormal haemoglobins: detection & characterization  

PubMed Central

Haemoglobin (Hb) abnormalities though quite frequent, are generally detected in populations during surveys and programmes run for prevention of Hb disorders. Several methods are now available for detection of Hb abnormalities. In this review, the following are discussed: (i) the methods used for characterization of haemoglobin disorders; (ii) the problems linked to diagnosis of thalassaemic trait; (iii) the strategy for detection of common Hb variants; and (iv) the difficulties in identification of rare variants. The differences between developing and industrialized countries for the strategies employed in the diagnosis of abnormal haemoglobins are considered. We mention the limits and pitfalls for each approach and the necessity to characterize the abnormalities using at least two different methods. The recommended strategy is to use a combination of cation-exchange high performance chromatography (CE-HPLC), capillary electrophoresis (CE) and when possible isoelectric focusing (IEF). Difficult cases may demand further investigations requiring specialized protein and/or molecular biology techniques. PMID:22089618

Wajcman, Henri; Moradkhani, Kamran

2011-01-01

344

Characterizing the performance of automatic road detection using error propagation  

Microsoft Academic Search

A methodology is introduced to predict the performance of automatic road detection using image examples of typical road types. In contrast to previous work on road detection, the focus is on characterizing the detection performance to achieve reliable performance measures of the detection. It is studied how noise, like road markings, shadows, trees and buildings, influences the detection of road.

Sidharta Gautama; Werner Goeman; Johan D'haeyer; Wilfried Philips

2006-01-01

345

Bat Detective  

NSDL National Science Digital Library

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.

Zooniverse

2014-05-14

346

PROGRESS AND PROBLEMS IN THE APPLICATION OF FOCUSED ULTRASOUND FOR BLOOD-BRAIN BARRIER DISRUPTION  

PubMed Central

Advances in neuroscience have resulted in the development of new diagnostic and therapeutic agents for potential use in the central nervous system (CNS). However, the ability to deliver the majority of these agents to the brain is limited by the blood–brain barrier (BBB), a specialized structure of the blood vessel wall that hampers transport and diffusion from the blood to the brain. Many CNS disorders could be treated with drugs, enzymes, genes, or large-molecule biotechnological products such as recombinant proteins, if they could cross the BBB. This article reviews the problems of the BBB presence in treating the vast majority of CNS diseases and the efforts to circumvent the BBB through the design of new drugs and the development of more sophisticated delivery methods. Recent advances in the development of noninvasive, targeted drug delivery by MRI-guided ultrasound-induced BBB disruption are also summarized. PMID:18511095

Vykhodtseva, Natalia; McDannold, Nathan; Hynynen, Kullervo

2008-01-01

347

(Aerodynamic focusing of particles and heavy molecules)  

SciTech Connect

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.

de la Mora, J.F.

1990-01-08

348

Keeping the Hubble Space Telescope in focus  

NASA Astrophysics Data System (ADS)

The Hubble Space Telescope is a Ritchie-Chrétien optical design with a main primary concave mirror followed by a convex secondary. The focus is determined by the position of each of these two mirrors. The truss containing them is made of graphite epoxy which has very low thermal expansion. Nevertheless, temperature variations do cause the mirror separation to vary by several microns within an orbit. Additionally, outgassing of water vapor causes a long-term shrinkage which soon after launch in 1990 varied by more than 2 microns per month. This necessitated adjusting the position of the secondary mirror every few months. Currently this rate is greatly reduced and adjustments are needed less than once per year. The focus is monitored monthly to continually assess the need for such adjustments. The measurements have been used to develop models to predict the focus at times between measurements to assist in the analysis of observations. Detailed focus knowledge is of value in photometry, coronagraphy and image deconvolution. The various focus models that have been applied so far are described with an evaluation of their performance. Continuing attempts to refine the model will be discussed.

Cox, Colin; Lallo, Matthew

2012-09-01

349

Capillary isoelectric focusing of native and inactivated microorganisms.  

PubMed

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

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

2007-07-01

350

DNA-based highly tunable particle focuser  

NASA Astrophysics Data System (ADS)

DNA is distinguished by both long length and structural rigidity. Classical polymer theories predict that DNA enhances the non-Newtonian elastic properties of its dilute solution more significantly than common synthetic flexible polymers because of its larger size and longer relaxation time. Here we exploit this property to report that under Poiseuille microflow, rigid spherical particles laterally migrate and form a tightly focused stream in an extremely dilute DNA solution (0.0005 (w/v)%). By the use of the DNA solution, we achieve highly efficient focusing (>99.5%) over an unprecedented wide range of flow rates (ratio of maximum to minimum flow rates ~400). This highly tunable particle-focusing technique can be used in the design of cost-effective portable flow cytometers, high-throughput cell analysis and also for cell sorting by size. We demonstrate that DNA is an efficient elasticity enhancer, which originates from its unique structural properties.

Kang, Kyowon; Lee, Sung Sik; Hyun, Kyu; Lee, Seong Jae; Kim, Ju Min

2013-10-01

351

Focused plasmonic trapping of metallic particles  

PubMed Central

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

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

2013-01-01

352

Remote adjustable focus Raman spectroscopy probe  

DOEpatents

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.

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

1999-01-01

353

Laser-induced anisotropy near a focus  

NASA Astrophysics Data System (ADS)

Optically isotropic materials may become anisotropic when illuminated by a strong laser beam. The induced anisotropy is proportional to the beam intensity, and it produces a depolarization of the laser beam. If the material is placed near the beam focus, usually the induced depolarization is strong due to the high beam intensity. We observed that in terbium gallium garnet, however, the induced depolarization is reduced sharply near the focus. It presents a minimal dip at this position. This phenomenon was not observed previously. In our analysis, we show that the refractive index variations in both transverse and longitudinal directions contribute to the phase shift responsible for the depolarization. As a result, the observed dip is closely related to the beam divergence. The competition between these two contributions plays a key role in the polarization changes near the focus.

Chen, X.; Berger, H.

1999-09-01

354

Methods and Strategies: Concept-Focused Teaching  

NSDL National Science Digital Library

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.

Olson, Joanne K.

2008-12-01

355

Focusing and energy deposition inside random media.  

PubMed

The degree of control over waves transmitted through random media is determined by characteristics of the singular values of the transmission matrix. This Letter explores focusing and energy deposition in the interior of disordered samples and shows that these are determined by the singular values of the matrix relating the field channels inside a medium to the incident channels. Through calculations and simulations, we discovered that the variation with depth of the maximal energy density and the contrast in optimal focusing are determined by the participation number M(z) of the energy density eigenvalues, while its inverse gives the variance of the energy density at z in a single configuration. PMID:25361345

Cheng, Xiaojun; Genack, Azriel Z

2014-11-01

356

Light focusing in the Anderson regime.  

PubMed

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. PMID:25072204

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

2014-01-01

357

Focusing of light by random scattering  

E-print Network

Random scattering of light is what makes materials such as white paint, clouds and biological tissue opaque. We show that although light propagating in these media is diffuse, a high degree of control is possible as phase information is not irreversibly lost. Opaque objects such as eggshell or white paint focus coherent light as sharply as a lens when illuminated with a wavefront that inverts the wave diffusion. We demonstrate the construction of such wavefronts using feedback, achieving a focus that is 1000 times brighter than the diffusely transmitted light. Our results are explained quantitatively by a universal relation based on statistical optics.

I. M. Vellekoop; A. P. Mosk

2006-04-10

358

Optimization of the NLC final focus system  

SciTech Connect

An optimization scheme for final focus systems is discussed and applied to the NLC design. The optical functions at the defocusing sextupoles, the sextupole strength, and the length of the system must obey eight conditions that are imposed by the spot size increase due to higher-order aberrations, the effects of synchrotron radiation in the bending magnets, power supply ripple, magnet vibration tolerances, and the estimated orbit stability at the sextupoles. These eight conditions determine the minimum optimum length of the system. The NLC final focus design was shortened to this optimum.

Zimmermann, F.; Helm, R.; Irwin, J.

1995-06-01

359

Enhancement of filamentation postcompression by astigmatic focusing.  

PubMed

The energy scaling up of pulse postcompression is still an open issue. In this work we analyze the use of astigmatic focusing to improve the output pulses in a filamentation based postcompression setup. Unlike spherical conditions, astigmatic focusing enhances the output energy and the spectral broadening of the filament. This is due to the increase of critical power, allowing a considerable improvement of the postcompression energy and stability in a simple way. We demonstrated compression from FWHM 100 fs, 10 nm, 3 mJ input pulses to 13 fs, 142 nm, near 1 mJ pulses. PMID:21964124

Alonso, Benjamín; Borrego-Varillas, Rocío; Sola, Íñigo J; Varela, Óscar; Villamarín, Ayalid; Collados, M Victoria; Román, Julio San; Bueno, Juan M; Roso, Luis

2011-10-01

360

Focusing polychromatic light through scattering media  

NASA Astrophysics Data System (ADS)

We demonstrate enhanced focusing of polychromatic light through strongly scattering media. The experimental results validate a theoretical relationship among source bandwidth, sample bandwidth, and initial contrast of a far-field speckle. For various combinations of source bandwidth and sample bandwidth, we optimize far-field focal intensity enhancement using a MEMS spatial light modulator to modulate the source beam prior to its propagation through the medium. We achieve focus optimization using a sequential coordinate descent algorithm and Hadamard basis functions to control the spatial phase of the modulator. Enhancement, the ratio of optimized focal intensity to initial speckle mean intensity, is shown to vary monotonically with initial contrast.

Paudel, Hari P.; Stockbridge, Chris; Mertz, Jerome; Bifano, Thomas

2013-03-01

361

The "Best Worst" Field Optimization and Focusing  

NASA Technical Reports Server (NTRS)

A simple algorithm for optimizing and focusing lens designs is presented. The goal of the algorithm is to simultaneously create the best and most uniform image quality over the field of view. Rather than relatively weighting multiple field points, only the image quality from the worst field point is considered. When optimizing a lens design, iterations are made to make this worst field point better until such a time as a different field point becomes worse. The same technique is used to determine focus position. The algorithm works with all the various image quality metrics. It works with both symmetrical and asymmetrical systems. It works with theoretical models and real hardware.

Vaughnn, David; Moore, Ken; Bock, Noah; Zhou, Wei; Ming, Liang; Wilson, Mark

2008-01-01

362

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

NASA Astrophysics Data System (ADS)

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

Ong, Rene A.; Covault, Corbin E.

2009-05-01

363

SWCX Emission from the Helium Focusing Cone - Preliminary Results  

NASA Technical Reports Server (NTRS)

Preliminary results from an XMM-Newton campaign to study solar wind charge exchange (SWCX) emission from the heliospheric focusing cone of interstellar helium are presented. The detections of enhanced O VII and O VIII emission from the cone are at the 2(sigma) and 4(sigma) levels. The solar wind charge exchange (SWCX) emission in the heliosphere not associated with distinct objects (e.g., comets and planets including exospheric material in and near Earth s magnetosheath) is proportional to the flux of the solar wind and the space density of neutral material. The neutral material originates in the interstellar medium (ISM) and passes through the solar system due to the relative motion of the Sun and the ISM. The flow of the neutral material through the solar system is strongly perturbed by the Sun both by gravity and by radiation pressure. Because of the relative radiative scattering cross sections and the effect of solar gravitation the density of interstellar hydrogen near the Sun is reduced while interstellar helium is gravitationally focused. This creates a helium focusing cone downstream of the Sun [e.g., 1, and references therein].

Snowden, S. L.; Kuntz, K. D.; Collier, M. R.

2008-01-01

364

High Resolution Double-Focusing Isotope Ratio Mass Spectrometry  

NASA Astrophysics Data System (ADS)

In recent years isotope ratio mass spectrometry has extended to the capability of quantifying very small isotope signatures related with low abundances and simultaneously detecting molecular masses such as isotopomers and isotopologues containing clumped isotopes. Some of those applications are limited by molecular interferences like different gas molecules with the same nominal mass, e.g. Ar/O2, adducts of the same molecule or of different molecules, and very small isotope abundances. The Thermo Scientific MAT 253 ULTRA is the next generation of high precision gas isotope ratio mass spectrometry, which combines a 10 KV gas ionization source (Thermo Scientific MAT 253) with a double focusing multi-collector mass analyzer (Thermo Scientific Neptune) and reduces those limitations by measuring isotope ratios on a larger dynamic range with high precision. Small ion beam requirements and high sensitivity are achieved by signal-to-noise improvements through enhanced ion beam amplification in faraday cups and ion counters. Interfering backgrounds, e.g. interfering isotopologues or isobaric ions of contaminants, are dramatically decreased by a dynamic range increase combined with high evacuation leading to undisturbed ion transmission through the double-focusing analyser. Furthermore, automated gain calibration for mathematical baseline corrections, switchable detector arrays, ion source control, analyser focusing and full data export is controlled under Isodat data control. New reference/sample strategies are under investigation besides incorporation of the continuous-flow technique and its versatile inlet devices. We are presenting first results and applications of the MAT 253 Ultra.

Radke, J.; Deerberg, M.; Hilkert, A.; Schlüter, H.-J.; Schwieters, J.

2012-04-01

365

Monocular Precrash Vehicle Detection: Features and Classifiers  

Microsoft Academic Search

Robust and reliable vehicle detection from images ac- quired by a moving vehicle (i.e., on-road vehicle detection) is an im- portant problem with applications to driver assistance systems and autonomous, self-guided vehicles. The focus of this work is on the issues of feature extraction and classification for rear-view vehicle detection. Specifically, by treating the problem of vehicle detection as a

Zehang Sun; George Bebis; Ronald Miller

2006-01-01

366

Early Detection  

Cancer.gov

This group identifies and ascertains the effectiveness of both the operating characteristics and the impacts on mortality, and immediate and downstream risks of molecular and imaging cancer detection technologies and practices. It systematically assesses

367

Draft Detectives  

NSDL National Science Digital Library

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).

Sciencenter

2010-01-01

368

Detection Technology  

Cancer.gov

Our ability to detect, diagnose and treat cancer will most likely be based on the molecular changes that distinguish cancer cells from their normal counterpart. Having reliable detection technologies to identify tumors early is therefore crucial before they become invasive. Development of technologies to quantitate molecular changes at all levels of gene expression, and to integrate the information is needed to identify molecular alterations that are selectively expressed in pre-invasive lesions, and correlated with tumor aggression.

369

SAR data focusing using seismic migration techniques  

Microsoft Academic Search

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

Ciro Cafforio; Claudio Prati; Fabio Rocca

1991-01-01

370

X-ray catastrophe focusing with ferroelectrics  

NASA Astrophysics Data System (ADS)

Familiar ripple patterns reflected from water waves and the characteristic cusp of light seen in the bottom of a coffee cup are examples of “catastrophe” optics, where focusing occurs without need for highly engineered optical elements; catastrophe theory provides the mathematical tools needed to describe the stability and topology of the caustics that produce these effects. We have discovered catastrophe focusing in the diffraction of hard x-rays from crystalline wafers of ferroelectric lithium niobate, by diffracting monochromated synchrotron undulator radiation from surface planes while applying a voltage across the thin crystal. The presence of anti-phase ferroelectric domains causes a rippling of the surface that produces focusing at an x-ray CCD camera a half meter away. The catastrophe focusing pattern can be uniquely controlled by the applied voltage. These results suggest possible applications of catastrophe optics to x-ray microfocusing, and to the use of voltage-controlled patterned ferroelectrics as a new concept in x-ray optical devices.

Durbin, Stephen; Jach, Terrence; Kim, Sungwon; Gopalan, Venkatraman

2006-03-01

371

Standards of conduct: new focus, new challenges  

SciTech Connect

The new Standards apply to fewer employees and require less information, implying a lesser regulatory burden. However, when the Standards of Conduct are coupled with tough enforcement standards and other laws and regulations intended to level the playing field, Order No. 717 may not have lowered the barriers but rather merely adjusted them. Transmission providers must focus and toughen their compliance programs accordingly. (author)

Attanasio, Donna M.; O'Donnell, Earle H.

2009-03-15

372

July 2010 | Issue 18 Focus on nutrition  

E-print Network

- myths or miracles? 3 Fellowship honours research benefactor 3 Liggins researcher wins animal welfare comments 14 Take a fresh look at our institute 14 Liggins researcher wins animal welfare award pg4. Increasingly, attention is focusing on how individual components of our diet act at a molecular level

Auckland, University of

373

Focus Issue: Decisions, Great and Small  

NSDL National Science Digital Library

This Focus Issue of Science’s STKE concerns cellular "decision-making" in the nervous system, with Perspectives on how diet affects the "decision" of a neuron to fire and on the "decision" of progenitor cells to become neurons or glia.

Elizabeth M. Adler (American Association for the Advancement of Science;Associate Editor of Science's STKE REV); Nancy R. Gough (American Association for the Advancement of Science;Editor of Science's STKE REV)

2007-10-30

374

Thagard Website Focus Groups Variable M (SD)  

E-print Network

1 Thagard Website Focus Groups June 2010 Variable M (SD) (M=13) Range n % Age 21.92 19-28 13 Sex) · Adopt look and simplicity of current FSU web pages Format · Clean website (like Google) · ". . As far a clinician (6) · My only issue is that might . . . get the cut and paste message . . . it can get generic

Weston, Ken

375

Focusing Solenoids for the Mice Cooling Channel  

SciTech Connect

This report describes a design for focusing solenoids for the low beta sections for the proposed Muon Ionization Cooling Experiment (MICE). There are three focusing solenoid pairs that will be around the muon absorbers for MICE. The two solenoid coils have an inside diameter of 510 mm, a length of 180 mm, and a thickness of 100 mm. A distance of 260 mm separates the two coils in the pair. The coils are designed to operate at opposite polarity, in order to create a gradient field in the low beta sections of the MICE cooling channel. As result, the force pushing the coil pair apart approaches 270 metric tons when the coils operate close to the short sample current for the superconductor. The forces between the coils will be carried by a support structure that is both on the inside and the outside the coils. During some modes of operation for MICE, the coils may operate at the same polarity, which means that the force between the coils pushes them together. The focusing magnet must be designed for both modes of operation. This support structure for the coils will be part of the focusing magnet quench protection system.

Green, M.A. [Lawrence Berkeley National Laboratory, Berkeley CA 94720 (United States); Baynham, E.; Rochford, J.H. [Rutherford Appleton Laboratory, Chilton-Ditcot, OX11 0QX (United Kingdom); Barr, G.; Lau, W.; Yang, S. [Oxford University, Oxford, OX12JD (United Kingdom)

2004-06-23

376

Astellas' Drug Discovery Strategy: Focus on Oncology  

PubMed Central

Based on the goal of delivering innovative and reliable pharmaceutical products to cancer patients for whom no effective treatments exist, Astellas is focusing its efforts on a strategy of precision medicine in its drug discovery which is carried out at three research sites with diversity in their research platforms and research styles. PMID:22457362

Yanagita, Yutaka; Takenaka, Toichi

2012-01-01

377

Subaru Prime Focus Camera -- Suprime-Cam  

Microsoft Academic Search

We have built an 80-mega pixels (10240 × 8192) mosaic CCD camera, called Suprime-Cam, for the wide-field prime focus of the 8.2m Subaru telescope. Suprime-Cam covers a field of view 34' × 27', a unique facility among the 8-10m class telescopes, with a resolution of 0\\

Satoshi Miyazaki; Yutaka Komiyama; Maki Sekiguchi; Sadanori Okamura; Mamoru Doi; Hisanori Furusawa; Masaru Hamabe; Katsumi Imi; Masahiko Kimura; Fumiaki Nakata; Norio Okada; Masami Ouchi; Kazuhiro Shimasaku; Masafumi Yagi; Naoki Yasuda

2002-01-01

378

MEA BREAKOUT GROUP FOCUSED ON CCMs  

E-print Network

MEA BREAKOUT GROUP #12;TOPICS FOCUSED ON CCMs · IONOMER · CATALYST LAYER · PERFORMANCE · DEGRADATION · FUNDAMENTAL STUDIES #12;IONOMER · DEVELOP IMPROVED IONOMERS: PERFLUORINATED IONOMERS (O2 FOR ANODE/CATHODE ­ IONOMER CHEMISTRY · IONOMER/CATALYST INTERACTION · CL / MEMBRANE INTERACTION · IMPROVED

379

Environmental Flux and Locally Focused College Writing  

ERIC Educational Resources Information Center

This article reviews insights from place-based education and ecological models of writing to show how these theories can work together to shape locally focused composition pedagogies. From place-based education, the researcher takes an emphasis on physical specificity, and from ecological models of writing, the researcher takes an emphasis on…

Shepley, Nathan

2014-01-01

380

Simple focus assay for Encephalitozoon cuniculi  

Microsoft Academic Search

Summary In this in vitro infectivity assay for Encephalitozoon cuniculi, lesions due to the organism appeared as macroscopically distinct foci. The number of such foci was used as a direct measure of the number of infectious units in the original sample. The expected correlation between focus-forming units and 50% infectious doses was observed in limit dilution experiments. Encephalitozoon cuniculi (Microsporida,

D. Pye; J. C. Cox

1979-01-01

381

Automatic dynamic depth focusing for NDT  

NASA Astrophysics Data System (ADS)

Automatic Dynamic Depth Focusing (ADDF) is a function currently not available in state of the art phased array NDT instruments. However, it would be a valuable tool to inspect arbitrarily shaped parts or when the part-array geometry is not accurately known. ADDF will avoid the burden of computing and programming focal laws, the complications of CAD-based geometry descriptions and is an effective tool to adapt to changes in the probe-part geometry during the inspection. Furthermore, the dynamic depth focusing feature will yield the best possible image quality with phased array technology. This work proposes an ADDF technique based on a procedure that automatically obtains the array-part geometry and sets up all the required focusing parameters. The array-part geometry is estimated from the first echo time of arrival using a few trigger shots. A virtual array that operates in the second medium only allows computing the initial values for a real-time dynamic depth focusing hardware. This technique is well adapted to inspect parts of unknown or variable geometry, or when the distance and/or the alignment of the array probe with the part changes during the inspection. The overall procedure is relatively fast (about 2 seconds using standard computers), even faster than currently available geometry-based focal law calculators.

Camacho, Jorge; Cruza, Jorge F.; Fritsch, Carlos; Moreno, José M.

2014-02-01

382

Focus: The Communication Arts. Virginia English Bulletin.  

ERIC Educational Resources Information Center

Focusing on the communication arts, the articles in this volume include "Communication: The Echo in the Lives of Your Students"; "Communication through Interacting Curriculum Design"; "American Studies Provide Opportunity for Communication"; "Humanities-Oriented Independent Study"; "Composing for Real"; "The Editorial: A Teaching Device for…

Wimer, Frances N., Ed.

1973-01-01

383

Research Focus Stress hormones and mate choice  

E-print Network

Research Focus Stress hormones and mate choice Jerry F. Husak and Ignacio T. Moore Department suggested that glucocorticoid stress hormones can play a role in sexual selection. In terms of mate choice glucocorticoid levels. This appears to occur because stress hormones can be key mediators of many condition

Husak, Jerry F.

384

Focus of Attention and Putting Performance.  

ERIC Educational Resources Information Center

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…

Boutcher, Stephen H.; Crews, Debra J.

385

Focus Issue: Getting Excited About Glia  

NSDL National Science Digital Library

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.

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

2010-11-09

386

Controlled Spatiotemporal Focusing Through Turbid Media  

E-print Network

We apply adaptive beam shaping for the simultaneous spatial focusing and temporal compression of ultrashort pulses propagating through turbid media, in the context of nonlinear microscopy. We find that by optimizing a nonlinear two-photon signal, controlled temporal shaping is attainable using only the spatial degrees of control.

Katz, Ori; Small, Eran; Silberberg, Yaron

2010-01-01

387

Policy message A narrow focus on conventional  

E-print Network

Policy message n A narrow focus on conventional sanitation technologies and top- down planning often prevents improvement of sanitation in poor settlements. n Simple, affordable, effective tech studies featured here were conducted in: Lao PDR, Tanzania, and Nepal Local solutions for sanitation Urban

Richner, Heinz

388

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 to track and monitor the extent of the oil spill on a daily basis. Addi- tional airborne flights to observe not been affected by the oil spill, but the See OIL SPILL, page 2 Volume 5 Issue 6 www

389

Latinos and the Media. Focus "En Foco".  

ERIC Educational Resources Information Center

This issue focuses on Latin Americans and the media, with emphasis on portrayal of the Latin American in United States mass media. "Puerto Ricans and the Media: A Personal Statement" (B. Vasquez) recalls the author's experiences as a young girl in the New York City public schools and in an urban college. The critical importance of the media in…

Vasquez, Blanca, Ed.

1990-01-01

390

Expanding the Focus of Career Assessment.  

ERIC Educational Resources Information Center

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,…

Lock, Jared D.; Hogan, Robert

2000-01-01

391

Focus of NASA's Spaceliner 100 Investment Area  

NASA Technical Reports Server (NTRS)

This presentation discuss the goals and objectives of the SL100 Technology Focus. Some of the Technology objectives were to: increase system performance margin; drive down operations costs; drive down manufacturing and production costs; and drive down development test and evaluation costs.

Hueter, Uwe; Lyles, Garry (Technical Monitor)

2000-01-01

392

Superintendent Leadership: Focusing on District Culture  

ERIC Educational Resources Information Center

This report describes a problem-based learning project focusing on superintendent leadership and stakeholder influence of school district culture. Current research findings suggest the importance of superintendent leadership in assessing, influencing, and enhancing school district culture. Multiple scholars wrote literature in the area of…

Donnelly, Tanya A.; Adams, Jeffery S.; Smith, Dwayne E.

2012-01-01

393

Practitioner-Focused Degrees in Politics  

ERIC Educational Resources Information Center

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…

Craig, John

2010-01-01

394

Quality? Is it Allowed? FACTC Focus, 2006  

ERIC Educational Resources Information Center

"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…

Doerr, Mark, Ed.

2006-01-01

395

Weapon focus, arousal, and eyewitness memory  

Microsoft Academic Search

Weapon focus refers to the decreased ability to give an accurate description of the perpetrator of a crime by an eyewitness because of attention to a weapon present during that crime. In the first experiment, subjects viewed a mock crime scene in which a weapon was either highly visible or mostly hidden from view. Subjects in the highly visible weapon

Thomas H. Kramer; Robert Buckhout; Paul Eugeniot

1990-01-01

396

Changing Focus: Women's Peri-menopausal Journey  

Microsoft Academic Search

In this article I revisit results of research completed in the mid 1990s, & recently reviewed with women's updated input. The basic social process named “Changing Focus” that women use as they negotiate the perimenopausal transition is discussed. This process consists of five parts: Monitoring the voice of the woman within, Listening to the voices of others, Integrating the wisdom,

Cynthia R. McCloskey

2012-01-01

397

Family Life Education: Focus on Student Involvement.  

ERIC Educational Resources Information Center

This booklet presents many ideas for involving students in family life education programs. Designed primarily for use by family life educators, it includes such topics as the use of cognitive and affective objectives in family life education, organizing family studies content by generalizations, and focusing on the student as an active learner. It…

Green, Kinsey B.

398

Focus Issue: Coping with Cellular Stress  

NSDL National Science Digital Library

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.

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

2009-11-10

399

Implementation of a Focused Social Networking Crawler  

Microsoft Academic Search

Social networking sites are becoming more and more popular and thus there is increased value in attacking and exploiting them. The amount of users on them is attractive in terms of the information they make available. We implement a focused social networking crawler on the popular site, Facebook, in order to exploit user profile information and identify aspects of computer

Alice Leung; Roven Lin; Jesse Ng; Philip Szeto

400

A multicollector, cycloidal focusing, magnetic mass spectrometer  

Microsoft Academic Search

The design and appraisal of a mass spectrometer, based on the focusing properties of mutually perpendicular electric and magnetic fields, is described. This field geometry spatially separates ions as a linear function of mass along a focal plane. This allows the spectrometer to be used in applications requiring the simultaneous monitoring of many ion species of independently varying intensities, such

N. G. Adams; D. Smith

1974-01-01

401

Laser-induced anisotropy near a focus  

Microsoft Academic Search

Optically isotropic materials may become anisotropic when illuminated by a strong laser beam. The induced anisotropy is proportional to the beam intensity, and it produces a depolarization of the laser beam. If the material is placed near the beam focus, usually the induced depolarization is strong due to the high beam intensity. We observed that in terbium gallium garnet, however,

X. Chen; H. Berger

1999-01-01

402

Ballistic dispersion in temperature gradient focusing  

E-print Network

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

Santiago, Juan G.

403

Reframing Retention Strategy: A Focus on Process  

ERIC Educational Resources Information Center

When institutions engage in discussions regarding improving retention and graduation rates, invariably the conversation focuses on entering student characteristics, especially ACT and SAT scores and high school grades. Clearly, attracting and enrolling well-prepared and motivated high-ability students will certainly improve institutional measures…

Schroeder, Charles C.

2013-01-01

404

Focus Issue: Moving in the Right Direction  

NSDL National Science Digital Library

Cells interpret environmental cues to extend processes in the appropriate direction, descend upon sources of inflammation or necrosis, or determine the best path to the correct position in a developing organism. This Focus Issue of Science Signaling highlights the signaling pathways and mechanisms that enable cells to sense external signals and direct their movement accordingly.

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

2011-04-26

405

FOCUS: MALDI Exploring Infrared Wavelength Matrix-  

E-print Network

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 MALDI-mass spectrometry (MS) measurements of proteins make use of ultraviolet (UV) wavelength laser

Chait, Brian T.

406

Focus. Volume 26, Number 2, Fall 2009  

ERIC Educational Resources Information Center

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…

Caspar, Emma, Ed.

2009-01-01

407

EMOTIONALLY FOCUSED MARITAL THERAPY: AN OVERVIEW  

Microsoft Academic Search

The purpose of this article is to present a recently articulated approach to marital therapy in terms of theory, clinical strategies, and outcome research. The treatment assumes that the most appropriate model for adult intimacy is that of an emotional bond and integrates systemic and experiential change strategies, focusing particularly on resynthesizing the emotions underlying interactional positions.

Susan M. Johnson; Leslie S. Greenberg

1987-01-01

408

Focus Questions: The Engines of Lessons.  

ERIC Educational Resources Information Center

Argues that teachers can easily structure social studies lessons to enhance students' thinking skills by using carefully structured focus questions. States that such questions--often beginning with such words as "is,""could,""should," does," and "can,"--go beyond asking for simple recall of facts or shallow explanation, to requesting the solution…

Killoran, James

1987-01-01

409

Semantic Focusing Allows Fully Automated Single-Layer Slide Scanning of Cervical Cytology Slides  

PubMed Central

Liquid-based cytology (LBC) in conjunction with Whole-Slide Imaging (WSI) enables the objective and sensitive and quantitative evaluation of biomarkers in cytology. However, the complex three-dimensional distribution of cells on LBC slides requires manual focusing, long scanning-times, and multi-layer scanning. Here, we present a solution that overcomes these limitations in two steps: first, we make sure that focus points are only set on cells. Secondly, we check the total slide focus quality. From a first analysis we detected that superficial dust can be separated from the cell layer (thin layer of cells on the glass slide) itself. Then we analyzed 2,295 individual focus points from 51 LBC slides stained for p16 and Ki67. Using the number of edges in a focus point image, specific color values and size-inclusion filters, focus points detecting cells could be distinguished from focus points on artifacts (accuracy 98.6%). Sharpness as total focus quality of a virtual LBC slide is computed from 5 sharpness features. We trained a multi-parameter SVM classifier on 1,600 images. On an independent validation set of 3,232 cell images we achieved an accuracy of 94.8% for classifying images as focused. Our results show that single-layer scanning of LBC slides is possible and how it can be achieved. We assembled focus point analysis and sharpness classification into a fully automatic, iterative workflow, free of user intervention, which performs repetitive slide scanning as necessary. On 400 LBC slides we achieved a scanning-time of 13.9±10.1 min with 29.1±15.5 focus points. In summary, the integration of semantic focus information into whole-slide imaging allows automatic high-quality imaging of LBC slides and subsequent biomarker analysis. PMID:23585899

Lahrmann, Bernd; Valous, Nektarios A.; Eisenmann, Urs; Wentzensen, Nicolas; Grabe, Niels

2013-01-01

410

Numerical experimentation on focusing time and neutron yield in GN1 plasma focus machine  

NASA Astrophysics Data System (ADS)

In this paper, we have shown how we have fitted Lee's six phase model code to analyze the current waveform of the GN1 plasma focus machine working in deuterium gas. The Lee's 6-phase model codes was later configured to work between 0.5 to 6 Torr and the results of both focusing time and neutron yield was than compared with the published experimental results. The final results indicate that Lee's code, gives realistic plasma dynamics and focus properties together with a realistic neutron yield for GN1 plasma focus, without the need of any adjustable parameters, needing only to fit the computed current trace to a measured current trace.

Singh, Arwinder; Lee, Sing; Saw, Sor Heoh

2014-08-01

411

Characteristics of focused ion beam nanoscale Josephson devices  

NASA Astrophysics Data System (ADS)

The requirements of quantum metrology and nanoscience are driving the need for single-particle detection capability across a wide variety of physics areas, including quantum information processing, single-photon detection, nanoelectromechanical systems, nanomagnetism and spintronics. The single particles to be detected include atoms, molecules, photons, spins and even phonons, in the future. Nanoscale superconducting quantum interference devices (nanoSQUIDs) represent a new manifestation of an old but exciting superconducting technology which addresses some of these requirements. In this paper we describe a straightforward approach to fabricating Nb microbridge weak links using combined optical lithography and focused ion beams which may be used to fabricate nanoSQUIDs. The devices show non-hysteretic current-voltage characteristics and demonstrate very low noise, even at operating temperatures above 4.2 K. To improve our understanding of the superconducting properties of the Josephson microbridge/nanobridge junctions which have proved very successful in realizing low noise nanoSQUIDs we have carried out a combination of investigations. These include cryogenic resistance versus temperature (R(T)) and current-voltage characteristic measurements, atomic force microscope scans, controlled gallium (Ga) ion milling and implantation, and ion beam track modelling of these Josephson devices and Nb thin films.

Hao, L.; Cox, D. C.; Gallop, J. C.

2009-06-01

412

Detecting Earthquakes--Part 2.  

ERIC Educational Resources Information Center

Basic concepts associated with seismic wave propagation through the earth and the location of seismic events were explained in part 1 (appeared in January 1983 issue). This part focuses on the construction of a student seismometer for detecting earthquakes and underground nuclear explosions anywhere on the earth's surface. (Author/JN)

Isenberg, C.; And Others

1983-01-01

413

Person-Focused Care at Kaiser Permanente  

PubMed Central

Patient-focused care has been described as an extension of patient-centered care, recognizing that patients’ medical needs are best understood and addressed in the context of their entire lives, including their life goals and social, economic, emotional, and spiritual functioning. Kaiser Permanente is expanding its ability to care for members as whole persons, not just as patients, with sensitivity to nonmedical factors in planning and delivering care. We describe emerging examples in several areas: interdisciplinary care planning, behavior change, social care, patient-reported outcome measures, and Total Health. Realizing the vision of person-focused care requires taking every opportunity to fully recognizing that each patient we serve is first and foremost a person. PMID:24626077

Bellows, Jim; Young, Scott; Chase, Alide

2014-01-01

414

Atomic Focusing by Quantum Fields: Entanglement Properties  

E-print Network

The coherent manipulation of the atomic matter waves is of great interest both in science and technology. In order to study how an atom optic device alters the coherence of an atomic beam, we consider the quantum lens proposed by Averbukh et al [1] to show the discrete nature of the electromagnetic field. We extend the analysis of this quantum lens to the study of another essentially quantum property present in the focusing process, i.e., the atom-field entanglement, and show how the initial atomic coherence and purity are affected by the entanglement. The dynamics of this process is obtained in closed form. We calculate the beam quality factor and the trace of the square of the reduced density matrix as a function of the average photon number in order to analyze the coherence and purity of the atomic beam during the focusing process.

I. G. da Paz; H. M. Frazão; M. C. Nemes; J. G. Peixoto de Faria

2014-06-16

415

Self-focusing of whistler waves  

NASA Technical Reports Server (NTRS)

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.

Karpman, V. I.; Kaufman, R. N.; Shagalov, A. G.

1992-01-01

416

Mixed waste characterization, treatment & disposal focus area  

SciTech Connect

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.

NONE

1996-08-01

417

Plasma devices for focusing extreme light pulses  

NASA Astrophysics Data System (ADS)

Since the inception of the laser, there has been a constant push toward increasing the laser peak intensity, as this has lead to opening the exploration of new territories, and the production of compact sources of particles and radiation with unprecedented characteristics. However, increasing the peak laser intensity is usually performed by enhancing the produced laser properties, either by lowering its duration or increasing its energy, which involves a great level of complexity for the laser chain, or comes at great cost. Focusing tightly is another possibility to increase the laser intensity, but this comes at the risk of damaging the optics with target debris, as it requires their placement in close proximity to the interaction region. Plasma devices are an attractive, compact alternative to tightly focus extreme light pulses and further increase the final laser intensity.

Fuchs, J.; Gonoskov, A. A.; Nakatsutsumi, M.; Nazarov, W.; Quéré, F.; Sergeev, A. M.; Yan, X. Q.

2014-05-01

418

A comparison-based approach to mispronunciation detection  

E-print Network

This thesis focuses on the problem of detecting word-level mispronunciations in nonnative speech. Conventional automatic speech recognition-based mispronunciation detection systems have the disadvantage of requiring a large ...

Lee, Ann, S.M. Massachusetts Institute of Technology

2012-01-01

419

Multi-focus Image Fusion Based on Salient Edge Information within Adaptive Focus-Measuring Windows  

Microsoft Academic Search

In this paper, we propose a new fusion scheme for multi-focus images based on some special edge information called discriminative edge points. A new focus measure is also proposed in this paper to identify which pixels in the source images will be included in the resultant image by evaluating the sum of neighborhood energy of the discriminative edge points within

Cheng I. Chen; Po-Whei Huang; Phen-Lan Lin

2009-01-01

420

The indirect approach of semi-focused groups : Expanding focus group research through role-playing  

Microsoft Academic Search

Purpose – The purpose of this paper is to present an alternative way of using focus groups in research – a role-play-enhanced focus group method – in which participants are presented with the challenge of dealing with a specific task while playing a familiar but nevertheless fictive role. Design\\/methodology\\/approach – The research is performed through an experimental approach in which

Frederic Bill; Lena Olaison

2009-01-01

421

Process of focusing mental effort on  

E-print Network

... · Male vs. Female · Speech vs. Buzzing · Listeners are bad at detecting meaning info ­ couldn't identify into working memory (short-term store) ­ Selection occurs "early", before info enters working memory Studies) Other channel no longer processed after filtering... short term memory meaning extracted here on after

Coulson, Seana

422

Small-Scale Self-focusing  

NASA Astrophysics Data System (ADS)

At high enough power, a beam propagating in a positive n 2 material will spontaneously break up into multiple filaments as a result of a transverse modulational instability. This chapter briefly surveys the essential physics, presents a linearized theory and summarizes experimental examples illustrating the dependence between optimal spatial frequency, gain coefficient, self-focusing length, beam intensity, and beam shape. A number of applications are discussed as well as the impact of this field on other scientific disciplines.

Campillo, Anthony J.

423

Animation of Gas Chromatography Solvent Focusing  

NSDL National Science Digital Library

This site has very good animations related to separations. It deals specifically with solvent focusing in gas chromatography. The animations are short (one to two minutes) and can easily be shown in class as part of a lecture. They are extremely helpful in illustrating key components and concepts of chromatographic systems. Users are encouraged to explore the site and the other brief animations as well. Separate links to other simulations by the same company (TRSL) are also listed on ASDL.

2011-05-09

424

Permanent magnet focused X-band photoinjector  

DOEpatents

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.

Yu, David U. L. (Rancho Palos Verdes, CA); Rosenzweig, James (Los Angeles, CA)

2002-09-10

425

Sound focusing by gradient index sonic lenses  

E-print Network

Gradient index sonic lenses based on two-dimensional sonic crystals are here designed, fabricated and characterized. The index-gradient is achieved in these type of flat lenses by a gradual modification of the sonic crystal filling fraction along the direction perpendicular to the lens axis. The focusing performance is well described by an analytical model based on ray theory as well as by numerical simulations based on the multiple-scattering theory.

Alfonso Climente; Daniel Torrent; Jose Sanchez-Dehesa

2010-06-14

426

Sound focusing by gradient index sonic lenses  

E-print Network

Gradient index sonic lenses based on two-dimensional sonic crystals are here designed, fabricated and characterized. The index-gradient is achieved in these type of flat lenses by a gradual modification of the sonic crystal filling fraction along the direction perpendicular to the lens axis. The focusing performance is well described by an analytical model based on ray theory as well as by numerical simulations based on the multiple-scattering theory.

Climente, Alfonso; Sanchez-Dehesa, Jose

2010-01-01

427

Sound focusing by gradient index sonic lenses  

NASA Astrophysics Data System (ADS)

Gradient index sonic lenses based on two-dimensional sonic crystals are here designed, fabricated, and characterized. The index-gradient is achieved in these type of flat lenses by a gradual modification of the sonic crystal filling fraction along the direction perpendicular to the lens axis. The focusing performance is well described by an analytical model based on ray theory as well as by numerical simulations based on the multiple-scattering theory.

Climente, Alfonso; Torrent, Daniel; Sánchez-Dehesa, José

2010-09-01

428

Focus and dose characterization of immersion photoclusters  

Microsoft Academic Search

The process window for state of the art chip manufacturing continues to decrease, driven by higher NA exposure tools and lower k1 values. The benefits of immersion lithography for Depth of Focus (DoF) are well known. Yet even with this immersion boost, NA=1.35 tools can push DoF into sub-100nm territory. In addition, immersion processes are subject to new sources of

T. A. Brunner; D. Corliss; T. Wiltshire; C. P. Ausschnitt

2009-01-01

429

Focused beam scatterometry for deep subwavelength metrology  

NASA Astrophysics Data System (ADS)

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.

Brown, Thomas G.; Alonso, Miguel A.; Vella, Anthony; Theisen, Michael J.; Head, Stephen T.; Gillmer, Steven R.; Ellis, Jonathan D.

2014-03-01

430

Automatic focus control for facsimile cameras  

NASA Technical Reports Server (NTRS)

An electronic circuit for controlling the focus of facsimile cameras is described. The circuit consists of balanced a.c. amplifiers, two square law function generators, and a differential amplifier and power drive. The invention includes a method for maintaining the imaging sensor at the expected location of the focal plane as the facsimile camera scans a scene or terrain. A block diagram of the electronic circuitry is provided.

Sinclair, A. R.; Burcher, E. E.; Katzberg, S. J. (inventors)

1974-01-01

431

ION BEAM FOCUSING BY PLASMA GUN  

Microsoft Academic Search

Focusing of proton beam of energy 5 MeV, current 10 mA, pulse duration 30 s, obtained on the accelerator «Ural-5» by means of plasma has been investigated. The parameters of the plasma flow produced by a coaxial plasma gun are the followings: plasma density 10 11-1015 cm-3, temperature 1-3 eV, velocity 10 7 cm\\/s, time duration 500 s. Magnetic field

V. Belan; V. Butenko; B. Ivanov; V. Kiselev; A. Kitsenko; A. Linnik; V. Maslov; V. Ognivenko; I. Onischenko; V. Prishchepov; A. Yegorov

432

Microjetting from wave focusing on oscillating drops  

NASA Astrophysics Data System (ADS)

We present experimental observations of microjetting from an oscillating drop. The jet is generated by the focusing of axisymmetric capillary waves that overturn and collide at an apex of the drop. These jets are up to two orders of magnitude smaller than the original drops. We present two widely different configurations that produce such microjets. The first occurs on a satellite drop, produced by the pinch-off of a water drop from a vertical nozzle. The large oscillations following the contraction of the satellite bridge focus waves at the bottom, sending out a 30?m jet at 9.9m/s. The second jet arises when a water drop, containing surfactants, falls onto and passes through a hemispherical soap film. The gentle deformation of the drop creates a surface wave that focuses at its top, shooting out a tiny jet and entrapping a small bubble inside the drop. This jet is 16±5?m in diameter and emerges at 6.3m/s. In this configuration, the soap film wraps around the drop and acts as a sensor of the air flow, revealing that the liquid jet is preceded by a localized faster-moving air jet. The jetting in both configurations is quite robust and occurs even for slightly asymmetric conditions. These microjets appear for much lower values of the Reynolds and Weber numbers than previously observed, suggesting that free-surface jetting is not limited to the inviscid capillary-inertial regime, which has been the focus of much of the theoretical work.

Thoroddsen, S. T.; Etoh, T. G.; Takehara, K.

2007-05-01

433

Focused phosphorus ion beam implantation into silicon  

Microsoft Academic Search

Phosphorus implantation into (100) silicon using a 32-keV focused ion beam is investigated from the standpoints of electrical properties and damage to the implanted layers. Phosphorus ions are extracted from the Pt-P-Sb alloy liguid-metal-ion source. Electrical properties are measured by isochronal annealing with Hall measurements and radiation damage is evaluated using a transmission electron microscope. Compared with the conventional implantation

Y. Madokoro; S. Shukuri; K. Umemura; M. Tamura

1989-01-01

434

A review of focused ion beam sputtering  

Microsoft Academic Search

This paper reviews the applications of focused ion beam (FIB) sputtering for micro\\/nano fabrication. Basic principles of FIB\\u000a were briefly discussed, and then empirical and fundamental models for sputtering yield, material removal rate, and surface\\u000a roughness were presented and compared. The empirical models were more useful for application compared to fundamental models.\\u000a Fabrication of various micro and nano structures was

Mohammad Yeakub Ali; Wayne Hung; Fu Yongqi

2010-01-01

435

The weapon focus effect in child eyewitnesses  

Microsoft Academic Search

The present study investigated whether children would exhibit the weapon focus effect that has been demonstrated with adult eyewitnesses. Participants (4- and 5-year-olds, 7- and 8-year-olds, and adults) watched a videotape in which a target individual portraying one of two schema roles and holding either a weapon or a neutral object steals some money. Witnesses of all ages described the

Kerri L. Pickel; Dana B. Narter; Molly M. Jameson; Thomas T. Lenhardt

2008-01-01

436

Focus Issue: Regulation of Lymphocyte Function  

NSDL National Science Digital Library

During the month of July, Science Signaling has highlighted mechanisms by which lymphocytes of the innate and adaptive immune responses are regulated to promote effective immunity and prevent inappropriate and damaging responses. Research Articles and Perspectives in this series and the Archives focus on the mechanisms by which the functions of T cells, B cells, and natural killer cells are regulated and the therapeutic implications of understanding the regulation of these cells.

Ernesto Andrianantoandro (American Association for the Advancement of Science;Science Signaling REV); John F. Foley (American Association for the Advancement of Science;Science Signaling REV)

2012-07-31

437

Focus on high energy density physics  

NASA Astrophysics Data System (ADS)

High-energy-density physics concerns the behavior of systems at high pressure, often involving the interplay of plasma, relativistic, quantum mechanical and electromagnetic effects. The field is growing rapidly in its scope of activity thanks to advances in experimental, laser and computational technologies. This ‘focus on’ collection presents papers discussing forefront research that spans the field, providing a sense of its breadth and of the interlinking of its parts.

Drake, R. Paul; Norreys, Peter

2014-06-01

438

STEM Focus in Innoventure Competition Theme  

SciTech Connect

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.

None

2010-03-31

439

Emotion-Focused Therapy: A Synopsis  

Microsoft Academic Search

The basic principles of an emotion-focused approach to therapy (EFT) are presented. In this view, emotion is seen as foundational in the construction of the self and is a key determinant of self-organization. As well as simply having emotion, people also live in a constant process of making sense of their emotions. Personal meaning emerges by the self-organization and explication

Leslie Greenberg

2006-01-01

440

Focus on thermoelectric effects in nanostructures  

NASA Astrophysics Data System (ADS)

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.

Sánchez, David; Linke, Heiner

2014-11-01

441

Plasma focus characteristics using stainless steel anode  

Microsoft Academic Search

In a low energy (2.3 kJ) Mather-type plasma focus with stainless steel anode, neutron and x-ray emission is investigated by employing time-integrated and time resolved detectors. A neutron yield of 3.5 × 108 is observed, which is almost double the yield when a copper anode is used. It is speculated that a low sputtering yield of the anode material lowers

M. Zakaulah; Imtiaz Ahmad; M. Shafique; Salma Khanam; A. R. Omar; M. Mathuthu; G. Murtaza; M. M. Beg

1997-01-01

442

Focus Issue: RNA, A Multifunctional Molecule  

NSDL National Science Digital Library

This week’s issues of Science, Science’s STKE, and SAGE KE (www.sciencemag.org/sciext/rna/) focus on the increasing complexity that RNA brings to cellular biology. STKE resources include Reviews, Perspectives, and Teaching Resources. STKE specifically looks at the roles for small RNAs in regulation of gene expression and how mRNAs can be selectively activated from cytoplasmic macromolecular structures, RNA granules, to contribute to such processes as synaptic plasticity.

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

2005-09-06

443

Focusing DIRC Design for Super B  

SciTech Connect

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].

Va'Vra, J.; /SLAC

2009-12-17

444

Carbonitriding of silicon using plasma focus device  

SciTech Connect

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.

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

445

Manganese Neurotoxicity: A Focus on the Neonate  

PubMed Central

Manganese (Mn) is an essential trace metal found in all tissues, and it is required for normal amino acid, lipid, protein, and carbohydrate metabolism. While Mn deficiency is extremely rare in humans, toxicity due to overexposure of Mn is more prevalent. The brain appears to be especially vulnerable. Mn neurotoxicity is most commonly associated with occupational exposure to aerosols or dusts that contain extremely high levels (> 1-5 mg Mn/m3) of Mn, consumption of contaminated well water, or parenteral nutrition therapy in patients with liver disease or immature hepatic functioning such as the neonate. This review will focus primarily on the neurotoxicity of Mn in the neonate. We will discuss putative transporters of the metal in the neonatal brain and then focus on the implications of high Mn exposure to the neonate focusing on typical exposure modes (e.g., dietary and parenteral). Although Mn exposure via parenteral nutrition is uncommon in adults, in premature infants, it is more prevalent, so this mode of exposure becomes salient in this population. We will briefly review some of the mechanisms of Mn neurotoxicity and conclude with a discussion of ripe areas for research in this underreported area of neurotoxicity. PMID:17084903

Erikson, Keith M.; Thompson, Khristy; Aschner, Judy; Aschner, Michael

2007-01-01

446

Nanoscintillators for radiation detection  

NASA Astrophysics Data System (ADS)

In the search for faster, more effective methods for detection of and protection against radiological weapons, advances in materials for radiation detection are a critical component of any successful strategy. This work focuses on producing inexpensive, but highly sensitive, nanoparticle alternatives to existing single-crystal installations. Attention is given to particular types of promising inorganic scintillators: LaF3, yttrium-aluminum-garnet (YAG), and SrF2, each one an inorganic host doped with additional elements that encourage luminescent decay and increase effective Z-value. I examine the possible routes to synthesize these compounds, and the difficulties and benefits of each method. After synthesizing these materials, testing was performed to determine comparative performance against each other and commercial solutions, identify structural and compositional characteristics, and explore routes for fixing the scintillators into a detector assembly. The unifying goal is to develop a scintillating material suitable for consistent dosimetry and radio-isotope identification applications.

Hall, Ryan Gregory

447

Neural correlates of the perception of contrastive prosodic focus in French: a functional magnetic resonance imaging study.  

PubMed

This functional magnetic resonance imaging (fMRI) study aimed at examining the cerebral regions involved in the auditory perception of prosodic focus using a natural focus detection task. Two conditions testing the processing of simple utterances in French were explored, narrow-focused versus broad-focused. Participants performed a correction detection task. The utterances in both conditions had exactly the same segmental, lexical, and syntactic contents, and only differed in their prosodic realization. The comparison between the two conditions therefore allowed us to examine processes strictly associated with prosodic focus processing. To assess the specific effect of pitch on hemispheric specialization, a parametric analysis was conducted using a parameter reflecting pitch variations specifically related to focus. The comparison between the two conditions reveals that brain regions recruited during the detection of contrastive prosodic focus can be described as a right-hemisphere dominant dual network consisting of (a) ventral regions which include the right posterosuperior temporal and bilateral middle temporal gyri and (b) dorsal regions including the bilateral inferior frontal, inferior parietal and left superior parietal gyri. Our results argue for a dual stream model of focus perception compatible with the asymmetric sampling in time hypothesis. They suggest that the detection of prosodic focus involves an interplay between the right and left hemispheres, in which the computation of slowly changing prosodic cues in the right hemisphere dynamically feeds an internal model concurrently used by the left hemisphere, which carries out computations over shorter temporal windows. PMID:22488985

Perrone-Bertolotti, Marcela; Dohen, Marion; Lœvenbruck, Hélène; Sato, Marc; Pichat, Cédric; Baciu, Monica

2013-10-01

448

Fingerprint detection  

DOEpatents

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.

Saunders, George C. (Rt. 1, Box 428B, Espanola, NM 87532)

1992-01-01

449

[Current recrudescence of human trypanosomiasis in the Sangha focus (basin) in the Congo].  

PubMed

In the Congo the Sangha focus of sleeping sickness caused more than 500,000 deaths in the early 20th century. Despite many years of quiescence many new cases have been detected since the early eighties. In 1987 an investigation found 43 infected patients within 5 villages (during the same year, 74 cases were detected from both investigation and passive detection). In December 1989 our further investigation found 96 new documented cases (115 for the whole year). The prevalence is increasing and the proportion of early stage in comparison with later stage is decreasing. The age diagram resembles that of the early 20th century. Despite the fact that the survey in 1989, extracted twice as many patients as in 1987 passive detection detected 99 infected patients in 1990, three times as many cases as in 1988, and places the "Sangha focus" in IId place in the Congo, after the "Bouenza focus". As only river transport is available to have access to that focus, the Congo will be faced with considerable difficulties in the future. PMID:1596955

Jannin, J; Penchenier, L; Eozenou, P; Ventrou, P; Mialebama, J; Louya, F; Bobenda, T; Samba, F; Coddy Zitsamele, R

1992-01-01

450

Optical Range-Finding from Image Focus  

NASA Astrophysics Data System (ADS)

Scope of the study. Much of the labor-intensive work in agriculture consists of reaching out, grasping an object, and then placing the object in a desired position. This repetitious work exploits the unsurpassed hand-eye coordination in human beings. Substitution of machines for manual labor will require simulation of human hand-eye coordination. Most robots in agricultural applications will need the ability to recognize and manipulate three-dimensional objects. With present technology, this requirement makes agricultural robotic systems uneconomical, except for special applications. A method for gauging the distance from a video camera to an object of interest was investigated. By using a calibrated camera-lens system, range was related to focus. Optimum focus of the image was determined by maximizing the high -frequency content of the Fourier transform of the object image. The Walsh-Hadamard transform was investigated as an alternative focusing function. Software was developed to determine optimum image focus and control a motorized camera lens. Findings and conclusions. Range values from the video camera to target objects were calculated by the system. Calculated values were compared with measured distances. Differences between calculated and actual distance averaged less than 0.5%. The Walsh-Hadamard transform provided focus information comparable to the Fourier transform. Using double precision floating-point arithmetic, the Walsh-Hadamard transform executed more than three times faster than the Fourier transform. Distance values calculated using the Walsh -Hadamard transform differed from values calculated with the Fourier transform by less than 1%. This system used a passive, non-triangulation technique to obtain the distance from the machine vision camera to the object of interest. A passive non-triangulation system was the simplest image acquisition requirements, since it does not require a second camera, structured lighting, camera movement, or time-of-flight measurement equipment. This simplicity must be balanced against the limited information obtained from a monocular view of the scene. For range measurement, this method should provide adequate information for robot arm guidance. The simple hardware requirements are also an advantage when designing a rugged, cost-effective system for use in agricultural applications.

Weckler, Paul Reese

451

Detection device  

DOEpatents

The present invention is directed to a detection device comprising: (1) an entrance chamber, (2) a central chamber, and (3) an exit chamber. The central chamber includes an ionizing gas, anode, and means for connecting the anode with an external power supply and pulse counter.

Smith, Jay E. (Pittsburgh, PA)

1984-01-01

452

Detection device  

DOEpatents

The present invention is directed to a detection device comprising: (1) an entrance chamber; (2) a central chamber; and (3) an exit chamber. The central chamber includes an ionizing gas, anode, and means for connecting the anode with an external power supply and pulse counter.

Smith, J.E.

1981-02-27

453

Fingerprint detection  

SciTech Connect

This patent describes a method for detection and visualization of latent fingerprints. It comprises contacting a substrate containing a latent print thereon the a colloidal metal composition at a pH from about 2.5 to about 4.0 for time sufficient to allow reaction of the colloidal metal composition with the latent print; and, preserving or recording the observable print.

Saunders, G.C.

1992-01-07

454

Measuring communicative participation using the FOCUS©1: Focus on the Outcomes of Communication Under Six  

PubMed Central

Background The FOCUS© is a new outcome tool for use by both parents and clinicians that measures changes in the communicative participation skills of preschool children. Changes in communicative participation skills as measured by the FOCUS were compared across three groups of children: those with speech impairments only (SI), those with language impairments only (LI) and those with both speech and language impairments (S/LI). Methods Participating families (n = 112, 75 male children) were recruited through 13 Canadian organizations. Children ranged from 10 months to 6 years 0 months (mean = 2.11 years; SD = 1.18 years) and attended speech-language