Note: This page contains sample records for the topic detecting focused ultrasound-induced from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Hemorrhage Detection During Focused-Ultrasound Induced Blood-Brain-Barrier Opening by Using Susceptibility-Weighted Magnetic Resonance Imaging  

Microsoft Academic Search

High-intensity focused ultrasound has been discovered to be able to locally and reversibly increase the permeability of the blood–brain barrier (BBB), which can be detected using magnetic resonance imaging (MRI). However, side effects such as microhemorrhage, erythrocyte extravasations or even extensive hemorrhage may also occur. Although current contrast-enhanced T1-weighted MRI can be used to detect the changes in BBB permeability,

Hao-Li Liu; Yau-Yau Wai; Wen-Shiang Chen; Jin-Chung Chen; Po-Hong Hsu; Xin-Yu Wu; Wen-Cheng Huang; Tzu-Chen Yen; Jiun-Jie Wang

2008-01-01

2

High Intensity Focused Ultrasound induced Gene Activation in Solid Tumors  

NASA Astrophysics Data System (ADS)

In this work, the feasibility of using high intensity focused ultrasound (HIFU) to activate trans-gene expression in a mouse tumor model was investigated. 4T1 cancer cells were implanted subcutaneously in the hind limbs of Balb/C mice and adenovirus luciferase gene vectors under the control of heat shock protein 70B promoter (Adeno-hsp70B-Luc) were injected intratumoraly for gene transfection. One day following the virus injection, the transfected tumors were heated to a peak temperature of 55, 65, 75, and 85°C, respectively, in 10s at multiple sites around the center of the tumor using a HIFU transducer operated at either 1.1-MHz (fundamental) or 3.3-MHz (3rd harmonic) frequency. Inducible luciferase gene expression was found to vary from 15-fold to 120-fold of the control group following 1.1-MHz HIFU exposure. The maximum gene activation was produced at a peak temperature of 65~75°C one day following HIFU exposure and decayed gradually to baseline level within 7 days. The inducible gene activation produced by 3.3-MHz HIFU exposure (75°C-10s) was found to be comparable to that produced by hyperthermia (42°C-30min). Altogether, these results demonstrate the feasibility of using HIFU as a simple and versatile physical means to regulate trans-gene expression in vivo. This unique feature may be explored in the future for a synergistic combination of HIFU-induced thermal ablation with heat-induced gene therapy for improved cancer therapy.

Liu, Yunbo; Kon, Takashi; Li, Chuanyuan; Zhong, Pei

2006-05-01

3

P0-3 Focused Ultrasound-Induced Molecular Delivery through the Blood-Brain Barrier  

Microsoft Academic Search

The delivery of gadolinium through the ultrasound- induced blood-brain barrier (BBB) openings of mice was investigated. The left hippocampus of mice (n=13) was sonicated (frequency: 1.525 MHz, pressure amplitude: 0.64 MPa, duty cycle: 20%, duration: 1 minute) in vivo through the intact skin and skull after the injection of pre-formed microbubbles (SonoVuereg; 25-30 mul). The BBB opening in mice was

James J. Choi; Shougang Wang; Barclay Morrison; Elisa E. Konofagou

2007-01-01

4

Transcranial MRI-guided focused ultrasound-induced blood-brain barrier opening in rats  

Microsoft Academic Search

The use of cavitation-enhanced MRI-guided focused ultrasound (FUS) to disrupt the blood-brain barrier (BBB) locally and enhance drug delivery to the brain was investigated in rats with an intact skull. Contrast-enhanced MR images of 50 rat brains exposed in multiple locations to FUS in the presence of microbubbles were analyzed to determine the minimum focal pressure amplitude needed to achieve

Lisa H. Treat; Nathan McDannold; Natalia Vykhodtseva; Kullervo Hynynen

2004-01-01

5

High intensity focused ultrasound-induced gene activation in sublethally injured tumor cells in vitro  

NASA Astrophysics Data System (ADS)

Cultured human cervical cancer (HeLa) and rat mammary carcinoma (R3230Ac) cells were transfected with vectors encoding green fluorescent protein (GFP) under the control of hsp70B promoter. Aliquots of 10-?l transfected cells (5×107 cells/ml) were placed in 0.2-ml thin-wall polymerase chain reaction tubes and exposed to 1.1-MHz high intensity focused ultrasound (HIFU) at a peak negative pressure P-=2.68 MPa. By adjusting the duty cycle of the HIFU transducer, the cell suspensions were heated to a peak temperature from 50 to 70 °C in 1-10 s. Exposure dependent cell viability and gene activation were evaluated. For a 5-s HIFU exposure, cell viability dropped from 95% at 50 °C to 13% at 70 °C. Concomitantly, gene activation in sublethally injured tumor cells increased from 4% at 50 °C to 41% at 70 °C. A similar trend was observed at 60 °C peak temperature as the exposure time increased from 1 to 5 s. Further increase of exposure duration to 10 s led to significantly reduced cell viability and lower overall gene activation in exposed cells. Altogether, maximum HIFU-induced gene activation was achieved at 60 °C in 5 s. Under these experimental conditions, HIFU-induced gene activation was found to be produced primarily by thermal rather than mechanical stresses.

Liu, Yunbo; Kon, Takashi; Li, Chuanyuan; Zhong, Pei

2005-11-01

6

Focused ultrasound induced blood-brain barrier disruption to enhance chemotherapeutic drugs (BCNU) delivery for glioblastoma treatment  

NASA Astrophysics Data System (ADS)

Focused ultrasound has been recently found to capable of temporally and reversibly disrupt local blood-brain barrier (BBB) and opens new frontier in delivering varies type of drugs into brain for central nerve system (CNS) disorder treatment. In this study, we aim to investigate the feasibility of delivering 1, 3-bits (2-chloroethyl) -1-nitrosourea (BCNU) to treat glioblastoma in animal models and evaluate whether this approach would gain treatment efficacy. Under the presence of microbubbles administration, a 400-kHz focused ultrasound was employed to deliver burst-tone ultrasonic energy stimulation to disrupt BBB in animal brains transcranially, and in-vivo monitored by magnetic-resonance imaging (MRI). C6-glioma cells were cultured and implanted into Sprague-Dawley rats as the brain-tumor model. BCNU deposited in brain was quantified by using high-performance liquid chromatography (HPLC), and brain tissues were examined histologically. MRI was employed to longitudinal evaluate the brain tumor treatment including the analysis of tumor progression and animal survival. We confirmed that the focused ultrasound, under the secure ultrasonic energy level, can significantly enhance the BCNU penetration through BBB over 300% than control without cause hemorrhage. Apparent improvement of treatment efficacy achieved by combining focused ultrasound with BCNU delivery, including significant suppression of tumor growth and a prolonged animal survival. This study highly support that this treatment strategy could be clinically-relevant and may help to provide another potential strategy in increasing local chemotherapeutic drugs for brain-tumor treatment.

Liu, Hao-Li; Hua, Mu-Yi; Chen, Pin-Yuan; Huang, Chiung-Yin; Wang, Jiun-Jie; Wei, Kuo-Chen

2010-03-01

7

Focused ultrasound induced blood-brain barrier disruption to enhance chemotherapeutic drugs (BCNU) delivery for glioblastoma treatment  

Microsoft Academic Search

Focused ultrasound has been recently found to capable of temporally and reversibly disrupt local blood-brain barrier (BBB) and opens new frontier in delivering varies type of drugs into brain for central nerve system (CNS) disorder treatment. In this study, we aim to investigate the feasibility of delivering 1, 3-bits (2-chloroethyl) -1-nitrosourea (BCNU) to treat glioblastoma in animal models and evaluate

Hao-Li Liu; Mu-Yi Hua; Pin-Yuan Chen; Chiung-Yin Huang; Jiun-Jie Wang; Kuo-Chen Wei

2010-01-01

8

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

NASA Astrophysics Data System (ADS)

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.

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

2010-09-01

9

Focused ultrasound-induced blood-brain barrier opening to enhance temozolomide delivery for glioblastoma treatment: a preclinical study.  

PubMed

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

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

2013-03-19

10

Paramagnetic perfluorocarbon-filled albumin-(Gd-DTPA) microbubbles for the induction of focused-ultrasound-induced blood-brain barrier opening and concurrent MR and ultrasound imaging  

NASA Astrophysics Data System (ADS)

This paper presents new albumin-shelled Gd-DTPA microbubbles (MBs) that can concurrently serve as a dual-modality contrast agent for ultrasound (US) imaging and magnetic resonance (MR) imaging to assist blood-brain barrier (BBB) opening and detect intracerebral hemorrhage (ICH) during focused ultrasound brain drug delivery. Perfluorocarbon-filled albumin-(Gd-DTPA) MBs were prepared with a mean diameter of 2320 nm and concentration of 2.903×109 MBs ml-1 using albumin-(Gd-DTPA) and by sonication with perfluorocarbon (C3F8) gas. The albumin-(Gd-DTPA) MBs were then centrifuged and the procedure was repeated until the free Gd3+ ions were eliminated (which were detected by the xylenol orange sodium salt solution). The albumin-(Gd-DTPA) MBs were also characterized and evaluated both in vitro and in vivo by US and MR imaging. Focused US was used with the albumin-(Gd-DTPA) MBs to induce disruption of the BBB in 18 rats. BBB disruption was confirmed with contrast-enhanced T1-weighted turbo-spin-echo sequence MR imaging. Heavy T2*-weighted 3D fast low-angle shot sequence MR imaging was used to detect ICH. In vitro US imaging experiments showed that albumin-(Gd-DTPA) MBs can significantly enhance the US contrast in T1-, T2- and T2*-weighted MR images. The r1 and r2 relaxivities for Gd-DTPA were 7.69 and 21.35 s-1mM-1, respectively, indicating that the MBs represent a positive contrast agent in T1-weighted images. In vivo MR imaging experiments on 18 rats showed that focused US combined with albumin-(Gd-DTPA) MBs can be used to both induce disruption of the BBB and detect ICH. To compare the signal intensity change between pure BBB opening and BBB opening accompanying ICH, albumin-(Gd-DTPA) MB imaging can provide a ratio of 5.14 with significant difference (p = 0.026), whereas Gd-DTPA imaging only provides a ratio of 2.13 and without significant difference (p = 0.108). The results indicate that albumin-(Gd-DTPA) MBs have potential as a US/MR dual-modality contrast agent for BBB opening and differentiating focused-US-induced BBB opening from ICH, and can monitor the focused ultrasound brain drug delivery process.

Liao, Ai-Ho; Liu, Hao-Li; Su, Chia-Hao; Hua, Mu-Yi; Yang, Hung-Wei; Weng, Yu-Ting; Hsu, Po-Hung; Huang, Sheng-Min; Wu, Shih-Yen; Wang, Hsin-Ell; Yen, Tzu-Chen; Li, Pai-Chi

2012-05-01

11

Automated detection of ocular focus.  

PubMed

We characterize objectively the state of focus of the human eye, utilizing a bull's eye photodetector to detect the double-pass blur produced from a point source of light. A point fixation source of light illuminates the eye. Fundus-reflected light is focused by the optical system of the eye onto a bull's eye photodetector [consisting of an annulus (A) and a center (C) of approximately equal active area]. To generate focus curves, C/A is measured with a range of trial lenses in the light path. Three human eyes and a model eye are studied. In the model eye, the focus curve showed a sharp peak with a full width at half maximum (FWHM) of +/-0.25 D. In human eyes, the ratio C/A was >4 at best focus in all cases, with a FWHM of +/-1 D. The optical apparatus detects ocular focus (as opposed to refractive error) in real time. A device that can assess focus rapidly and objectively will make it possible to perform low-cost, mass screening for focusing problems such as may exist in children at risk for amblyopia. PMID:15447031

Hunter, David G; Nusz, Kevin J; Gandhi, Nainesh K; Quraishi, Imran H; Gramatikov, Boris I; Guyton, David L

12

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

NASA Astrophysics Data System (ADS)

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

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

2005-10-01

13

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

PubMed

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. PMID:22734752

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

2012-06-01

14

Pharmacodynamic Analysis of Magnetic Resonance Imaging-Monitored Focused Ultrasound-Induced Blood-Brain Barrier Opening for Drug Delivery to Brain Tumors  

PubMed Central

Microbubble-enhanced focused ultrasound (FUS) can enhance the delivery of therapeutic agents into the brain for brain tumor treatment. The purpose of this study was to investigate the influence of brain tumor conditions on the distribution and dynamics of small molecule leakage into targeted regions of the brain after FUS-BBB opening. A total of 34 animals were used, and the process was monitored by 7T-MRI. Evans blue (EB) dye as well as Gd-DTPA served as small molecule substitutes for evaluation of drug behavior. EB was quantified spectrophotometrically. Spin-spin (R1) relaxometry and area under curve (AUC) were measured by MRI to quantify Gd-DTPA. We found that FUS-BBB opening provided a more significant increase in permeability with small tumors. In contrast, accumulation was much higher in large tumors, independent of FUS. The AUC values of Gd-DTPA were well correlated with EB delivery, suggesting that Gd-DTPA was a good indicator of total small-molecule accumulation in the target region. The peripheral regions of large tumors exhibited similar dynamics of small-molecule leakage after FUS-BBB opening as small tumors, suggesting that FUS-BBB opening may have the most significant permeability-enhancing effect on tumor peripheral. This study provides useful information toward designing an optimized FUS-BBB opening strategy to deliver small-molecule therapeutic agents into brain tumors.

Chu, Po-Chun; Chai, Wen-Yen; Hsieh, Han-Yi; Wang, Jiun-Jie; Wey, Shiaw-Pyng; Huang, Chiung-Yin; Wei, Kuo-Chen; Liu, Hao-Li

2013-01-01

15

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

16

Pharmacodynamic analysis of magnetic resonance imaging-monitored focused ultrasound-induced blood-brain barrier opening for drug delivery to brain tumors.  

PubMed

Microbubble-enhanced focused ultrasound (FUS) can enhance the delivery of therapeutic agents into the brain for brain tumor treatment. The purpose of this study was to investigate the influence of brain tumor conditions on the distribution and dynamics of small molecule leakage into targeted regions of the brain after FUS-BBB opening. A total of 34 animals were used, and the process was monitored by 7T-MRI. Evans blue (EB) dye as well as Gd-DTPA served as small molecule substitutes for evaluation of drug behavior. EB was quantified spectrophotometrically. Spin-spin (R1) relaxometry and area under curve (AUC) were measured by MRI to quantify Gd-DTPA. We found that FUS-BBB opening provided a more significant increase in permeability with small tumors. In contrast, accumulation was much higher in large tumors, independent of FUS. The AUC values of Gd-DTPA were well correlated with EB delivery, suggesting that Gd-DTPA was a good indicator of total small-molecule accumulation in the target region. The peripheral regions of large tumors exhibited similar dynamics of small-molecule leakage after FUS-BBB opening as small tumors, suggesting that FUS-BBB opening may have the most significant permeability-enhancing effect on tumor peripheral. This study provides useful information toward designing an optimized FUS-BBB opening strategy to deliver small-molecule therapeutic agents into brain tumors. PMID:23607093

Chu, Po-Chun; Chai, Wen-Yen; Hsieh, Han-Yi; Wang, Jiun-Jie; Wey, Shiaw-Pyng; Huang, Chiung-Yin; Wei, Kuo-Chen; Liu, Hao-Li

2013-03-31

17

Ultrasound-induced fluorescence (UIF):sonofluorescence (SF)  

Microsoft Academic Search

12 According to the principle of the multibubble cavitation oxidation and chemiluminescence of the luminol in aqueous alkaline solution, this paper introduces an ultrasound- induced fluorescence: sonofluorescence (SF) and designs its experimental set-up. Using the set-up, the authors detect the SF emission of the aqueous luminol-NaOH solution, take the pictures of the SF of the cavitating aqueous luminol- NaOH and

Huamao Li; Andong Xie; Ruo Feng; Yaojun Wan

2001-01-01

18

Landing airplanes, detecting traffic, and dark focus.  

PubMed

Misjudgments of position in flight and failures to detect other airborne traffic are casualties of the eternal tug-of-war between visible texture and the pilot's dark focus. The eye is lazy and resists the pull of a distant stimulus, preferring to rest at a relatively short focal distance, as it does in the dark or when looking at the sky. Judgments of apparent size are highly correlated with visual accommodation distance, and the difficulty of detecting airplanes on stationary collision courses is greatly aggravated when focus is trapped by structure close to the eyes. Subject, cockpit design, task, and environment variables all interact to determine what we think we see. PMID:7150159

Roscoe, S N

1982-10-01

19

Ultrasound-induced fluorescence (UIF):sonofluorescence (SF)  

NASA Astrophysics Data System (ADS)

12 According to the principle of the multibubble cavitation oxidation and chemiluminescence of the luminol in aqueous alkaline solution, this paper introduces an ultrasound- induced fluorescence: sonofluorescence (SF) and designs its experimental set-up. Using the set-up, the authors detect the SF emission of the aqueous luminol-NaOH solution, take the pictures of the SF of the cavitating aqueous luminol- NaOH and -NaHCO3 solutions and observe the impacts of Cu2+ on the SF spectra of the aqueous solutions of luminol-NaOH, -Ca(OH)2 and -Na2CO3. Finally, the authors discuss the experimental SF and its potential applications.

Li, Huamao; Xie, Andong; Feng, Ruo; Wan, Yaojun

2001-02-01

20

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

PubMed Central

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

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

2012-01-01

21

Effect of modulated ultrasound parameters on ultrasound-induced thrombolysis  

NASA Astrophysics Data System (ADS)

The potential of ultrasound to enhance enzyme-mediated thrombolysis by application of constant operating parameters (COP) has been widely demonstrated. In this study, the effect of ultrasound with modulated operating parameters (MOP) on enzyme-mediated thrombolysis was investigated. The MOP protocol was applied to an in vitro model of thrombolysis. The results were compared to a COP with the equivalent soft tissue thermal index (TIS) over the duration of ultrasound exposure of 30 min (p < 0.14). To explore potential differences in the mechanism responsible for ultrasound-induced thrombolysis, a perfusion model was used to measure changes in average fibrin pore size of clot before, after and during exposure to MOP and COP protocols and cavitational activity was monitored in real time for both protocols using a passive cavitation detection system. The relative lysis enhancement by each COP and MOP protocol compared to alteplase alone yielded values of 33.69 ± 12.09% and 63.89 ± 15.02% in a thrombolysis model, respectively (p < 0.007). Both COP and MOP protocols caused an equivalent significant increase in average clot pore size of 2.09 × 10-2 ± 0.01 µm and 1.99 × 10-2 ± 0.004 µm, respectively (p < 0.74). No signatures of inertial or stable cavitation were observed for either acoustic protocol. In conclusion, due to mechanisms other than cavitation, application of ultrasound with modulated operating parameters has the potential to significantly enhance the relative lysis enhancement compared to application of ultrasound with constant operating parameters.

Soltani, Azita; Volz, Kim R.; Hansmann, Doulas R.

2008-12-01

22

Biocompatible silicon quantum dots by ultrasound-induced solution route  

NASA Astrophysics Data System (ADS)

The water-soluble silicon quantum dots (QDs) of average diameter ~3 nm were prepared in organic solvent by ultrasound-induced solution route. This speedy rout produces the silicon QDs in the size range from 2 nm to 4 nm at room temperature and ambient pressure. The product yield of QDs was estimated to be higher than 60 % based on the initial NaSi weight. The surfaces of QDs were terminated with organic molecules including biocompatible ending groups (hydroxyl, amine and carboxyl) during simple preparation. Covalent attached molecules were characterized by FT-IR spectroscopy. These water-soluble passivation of QDs has just a little effect on the optical properties of original QDs.

Lee, Soojin; Cho, Woon-Jo

2004-10-01

23

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

NASA Astrophysics Data System (ADS)

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

Maruvada, Subha; Hynynen, Kullervo

2003-04-01

24

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

25

Enhancement of detecting defects in pipes with focusing techniques  

Microsoft Academic Search

Ultrasonic guided waves have been widely utilized for long range inspection of structures such as oil and petrochemical pipes. However, weldments, support, insulation, and attenuation make it difficult to examine pipe-like structures. In order to overcome such difficulties, it is desired to focus ultrasonic guided wave at the area under interrogation. In this paper, we discuss two focusing techniques: angular

To Kang; Dong-Hoon Lee; Sung-Jin Song; Hak-Joon Kim; Young-Do Jo; Hyun-Joon Cho

2011-01-01

26

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

27

Quantitative methods in pharmacovigilance: focus on signal detection.  

PubMed

Pharmacovigilance serves to detect previously unrecognised adverse events associated with the use of medicines. The simplest method for detecting signals of such events is crude inspection of lists of spontaneously reported drug-event combinations. Quantitative and automated numerator-based methods such as Bayesian data mining can supplement or supplant these methods. The theoretical basis and limitations of these methods should be understood by drug safety professionals, and automated methods should not be automatically accepted. Published evaluations of these techniques are mainly limited to large regulatory databases, and performance characteristics may differ in smaller safety databases of drug developers. Head-to-head comparisons of the major techniques have not been published. Regardless of previous statistical training, pharmacovigilance practitioners should understand how these methods work. The mathematical basis of these techniques should not obscure the numerous confounders and biases inherent in the data. This article seeks to make automated signal detection methods transparent to drug safety professionals of various backgrounds. This is accomplished by first providing a brief overview of the evolution of signal detection followed by a series of sections devoted to the methods with the greatest utilisation and evidentiary support: proportional reporting rations, the Bayesian Confidence Propagation Neural Network and empirical Bayes screening. Sophisticated yet intuitive explanations are provided for each method, supported by figures in which the underlying statistical concepts are explored. Finally the strengths, limitations, pitfalls and outstanding unresolved issues are discussed. Pharmacovigilance specialists should not be intimidated by the mathematics. Understanding the theoretical basis of these methods should enhance the effective assessment and possible implementation of these techniques by drug safety professionals. PMID:12580646

Hauben, Manfred; Zhou, Xiaofeng

2003-01-01

28

A public health focus on infertility prevention, detection, and management.  

PubMed

In 2002, 2 million American women of reproductive age were infertile. Infertility is also common among men. The Centers for Disease Control and Prevention (CDC) conducts surveillance and research on the causes of infertility, monitors the safety and efficacy of infertility treatment, and sponsors national prevention programs. A CDC-wide working group found that, despite this effort, considerable gaps and opportunities exist in surveillance, research, communication, and program and policy development. We intend to consult with other federal agencies, professional and consumer organizations, the scientific community, the health care community, industry, and other stakeholders, and participate in the development of a national public health plan for the prevention, detection, and management of infertility. PMID:18992879

Macaluso, Maurizio; Wright-Schnapp, Tracie J; Chandra, Anjani; Johnson, Robert; Satterwhite, Catherine L; Pulver, Amy; Berman, Stuart M; Wang, Richard Y; Farr, Sherry L; Pollack, Lori A

2008-11-06

29

Focus detection criterion for refocusing in multi-wavelength digital holography  

NASA Astrophysics Data System (ADS)

The majority of focus detection criteria reported is based on amplitude contrast. Due to phase wrapping, phase contrast was previously reported unsuitable for focus finding tasks. By taking the advantage of multi-wavelength digital holography, we propose a new focus detection criterion based on phase contrast. Experimental results are presented to prove the feasibility of the developed criterion. Possible applications of the developed technology include inspecting machined surfaces in the auto industry.

Xu, Li; Mater, Mike; Ni, Jun

2011-08-01

30

In Vitro localized release of thermosensitive liposomes with ultrasound-induced hyperthermia.  

PubMed

Localized drug delivery with ultrasound-induced hyperthermia can enhance the therapeutic index of chemotherapeutic drugs by improving efficacy and reducing systemic toxicity. A novel in vitro method for the activation of drug-loaded thermosensitive liposomes is described. In particular, a dual-compartment, acoustically transparent container is used in which thermosensitive liposomes suspended in cell culture medium are immersed in a thermally absorptive medium, glycerol. Hyperthermia is induced with ultrasound in the glycerol, which in turn heats the culture medium by thermal conduction. The method approximately mimics the in vivo scenario of thermosensitive liposomes collected in the interstitial spaces of tumors, where ultrasound induces hyperthermia in the tumor tissue, which in turn heats the thermosensitive liposomes by conduction and induces release of the encapsulated drug. The acoustic conditions for the desired hyperthermia are derived theoretically and validated experimentally. Eighty percent release of doxorubicin from thermosensitive liposomes is achieved. PMID:23972488

Mannaris, Christophoros; Efthymiou, Eleni; Meyre, Marie-Edith; Averkiou, Michalakis A

2013-08-22

31

Flux-focusing eddy current probe and rotating probe method for flaw detection  

Microsoft Academic Search

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

Buzz A. Wincheski; James P. Fulton; Shridhar C. Nath; John W. Simpson; Min Namkung

1994-01-01

32

Application of a focus formation assay for detection and titration of porcine epidemic diarrhea virus  

Microsoft Academic Search

A focus formation assay (FFA) for detection and titration of porcine epidemic diarrhea virus (PEDV) in a micro-culture system using Vero cells and PAP staining technique was evaluated. A linear correlation between the virus dilution and virus titer determined by FFA was observed between the range of 10 and 30 foci per well. Comparative analysis between FFA and plaque assay

Deu John M. Cruz; Hyun-Jin Shin

2007-01-01

33

Note: Focus error detection device for thermal expansion-recovery microscopy (ThERM)  

NASA Astrophysics Data System (ADS)

An innovative focus error detection method is presented that is only sensitive to surface curvature variations, canceling both thermoreflectance and photodefelection effects. The detection scheme consists of an astigmatic probe laser and a four-quadrant detector. Nonlinear curve fitting of the defocusing signal allows the retrieval of a cutoff frequency, which only depends on the thermal diffusivity of the sample and the pump beam size. Therefore, a straightforward retrieval of the thermal diffusivity of the sample is possible with microscopic lateral resolution and high axial resolution (~100 pm).

Domené, E. A.; Martínez, O. E.

2013-01-01

34

Detection of protein kinase substrates in tissue extracts after separation by isoelectric focusing.  

PubMed

Here we report a simple and useful method to detect endogenous substrates of protein kinases. When crude tissue extracts were resolved by liquid-phase isoelectric focusing (MicroRotofor) and the separated protein fractions were phosphorylated by protein kinases such as Ca(2+)/calmodulin-dependent protein kinase I or cAMP-dependent protein kinase, various proteins in the different fractions were efficiently phosphorylated. Since a higher number of substrates could significantly be detected using the resolved fractions by MicroRotofor as compared to direct analysis of the original tissue extracts, our present method will be applicable to the screening of endogenous substrates for various protein kinases. PMID:20807496

Senga, Yukako; Nagamine, Tadashi; Sekiguchi, Mari; Kaneko, Keisuke; Sueyoshi, Noriyuki; Kameshita, Isamu

2010-08-31

35

Magnetic focusing immunosensor for the detection of Salmonella typhimurium in foods  

NASA Astrophysics Data System (ADS)

From 1988 through 1992 Salmonellosis accounted for 27% of the total reported foodborne disease outbreaks and 57% of the outbreaks in which the pathogen was identified. The prevalence of Salmonellosis and the new requirements to monitor the organism as a marker in pathogen reduction programs will drive the need for rapid, on-site testing. A compact fiber optic fluorometer using a red diode laser as an excitation source and fiber probes for analyte detection has been constructed and used to measure Salmonella. The organisms were isolated with anti-Salmonella magnetic beads and were labeled with a secondary antibody conjugated to a red fluorescent dye. The response of the system was proportional to the concentration of Salmonella typhimurium from 3.2 X 105 colony forming units (CFU)/ml to 1.6 X 107 CFU/ml. The system was developed to utilize a fiber-optic magnetic focusing problem that attracted the magnetic microspheres to the surface of a sample chamber directly in front of the excitation and emission fibers. The signal obtained from a homogenous suspension of fluorescent magnetic microspheres was 9 to 10 picowatts. After focusing, the signal from the fluorescent labeled magnetic microspheres increased to 200 picowatts, approximately 20 times greater than the homogeneous suspension. The magnetic focusing assay detected 1.59 X 105 colony forming units/ml of Salmonella typhimurium cultured in growth media. The process of magnetic focusing in front of the fibers has the potential to reduce the background fluorescence from unbound secondary antibodies, eliminating several rinsing steps, resulting in a simple rapid assay.

Pivarnik, Philip E.; Cao, He; Letcher, Stephen V.; Pierson, Arthur H.; Rand, Arthur G.

1999-01-01

36

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

PubMed

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

Boyde, Alan

2003-02-01

37

Experimental demonstration of time-reversed reverberation focusing in a rough waveguide. Application to target detection  

NASA Astrophysics Data System (ADS)

For most shallow-water waveguides, the backscattered energy measured in a monostatic configuration is dominated by ocean bottom reverberation. A selected time-gated portion of the measured reverberation signals is used to provide a transfer function between a time-reversing array and a corresponding range interval on the bottom. Ultrasonic and at-sea experiments demonstrate focusing capabilities along the rough bottom interface of a time-reversing array using these reverberation signals only. The iterative time-reversal technique facilitates robust focusing along the ocean bottom, with little signal-processing effort involved and a priori information on the environment, and the enhancement of detection and localization of proud or buried targets in complex shallow-water environments. A passive implementation of the iterative time-reversal processing is used to construct reflectivity maps, similar to a sonar map, but with an enhanced contrast for the strongest reflectors (or scatterers), at the water-bottom interface. Ultrasonic and at-sea experiments show that targets lying on the seafloor located up to 400 wavelengths from the time-reversing array were detected over the bottom reverberation.

Sabra, Karim G.; Roux, Philippe; Song, Hee-Chun; Hodgkiss, William; Kuperman, William A.; Akal, Tuncay; Stevenson, Mark R.

2005-09-01

38

Flux-focusing eddy current probe and rotating probe method for flaw detection  

NASA Astrophysics Data System (ADS)

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, Buzz A.; Fulton, James P.; Nath, Shridhar C.; Simpson, John W.; Namkung, Min

1994-11-01

39

Dynamics of ultrasound-induced cavitation bubbles in non-Newtonian liquids and near a rigid boundary  

Microsoft Academic Search

The dynamics of ultrasound-induced cavitation bubbles situated in non-Newtonian liquids and near a rigid boundary are investigated experimentally by acoustic measurements and high-speed photography with up to 4 million frames\\/s. The non-Newtonian liquids consist of a 0.5% polyacrylamide (PAM) aqueous solution with a strong elastic component and a 0.5% carboxymethylcellulose aqueous solution with a weak elastic component. The maximum velocity

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

2004-01-01

40

Ultrasound-induced cavitation enhances the delivery and therapeutic efficacy of an oncolytic virus in an in vitro model  

Microsoft Academic Search

We investigated whether ultrasound-induced cavitation at 0.5MHz could improve the extravasation and distribution of a potent breast cancer-selective oncolytic adenovirus, AdEHE2F-Luc, to tumour regions that are remote from blood vessels. We developed a novel tumour-mimicking model consisting of a gel matrix containing human breast cancer cells traversed by a fluid channel simulating a tumour blood vessel, through which the virus

Miriam Bazan-Peregrino; Costas D. Arvanitis; Bassel Rifai; Leonard W. Seymour; Constantin-C. Coussios

41

Ultrasound-Induced Mild Hyperthermia as a Novel Approach to Increase Drug Uptake in Brain Microvessel Endothelial Cells  

Microsoft Academic Search

Purpose. Drug delivery to the central nervous system (CNS) is limited by the blood-brain barrier (BBB). Thus, a noninvasive and reversible method to enhance BBB permeation of drugs is highly desirable. In the present work, we studied if ultrasound-induced mild hyperthermia (USHT, 0.4 watts (W)\\/cm2 at 41°C) can enhance drug absorption in BBB endothelial cells, and we elucidated the mechanism

Cheong-Weon Cho; Yang Liu; Wesley N. Cobb; Thomas K. Henthorn; Kevin Lillehei; Uwe Christians; Ka-Yun Ng

2002-01-01

42

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

PubMed

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 varies linearly with ultrasound intensity and exposure times, it is independent of the duty cycle in the range of parameters studied. The enhancement is also directly proportional to the ultrasound energy density once the threshold value is crossed. For full thickness pig skin, the threshold value is about 222 J/cm(2). The overall dependence of transport enhancement on ultrasound parameters is similar to that of cavitation measured in a model system, pitting of aluminum foil. Specifically, the extent of pitting is proportional to ultrasound intensity and exposure time and is independent of duty cycle. Furthermore, the extent of pitting is also proportional to the ultrasound energy density. The similarity between the parametric dependence of transport enhancement and cavitation is consistent with previous findings that cavitation plays the dominant role in sonophoresis. PMID:10640579

Mitragotri, S; Farrell, J; Tang, H; Terahara, T; Kost, J; Langer, R

2000-01-01

43

Effect of contrast agent on the incidence of ultrasound-induced lung hemorrhage in rats  

NASA Astrophysics Data System (ADS)

The objective is to test further the hypothesis that if inertial cavitation in the vasculature of the lung is the physical mechanism responsible for ultrasound-induced lung hemorrhage, then the addition of cavitation nuclei to the blood will enhance the occurrence of lung hemorrhage. A factorial design was used to study the effects of two types of injected agents (IA; 0.25 mL per rat of saline or Optison given intravenously) and two levels of pulsed ultrasound exposure (UE; in situ peak rarefactional pressures of 2.74 and 5.86 MPa) on the incidence and size of lung lesions. Ten 10-to-11-week-old Sprague-Dawley rats were exposed at each of the four combinations of IA and UE at 3.1 MHz for 10 s (1-kHz PRF, 1.2-microns PD). Rats administered contrast agent prior to exposure did not have an increase in lesion occurrence or size compared to rats that received saline with no contrast agent. These results provide further evidence that the mechanism of lung hemorrhage is not inertial cavitation. These findings are consistent with another group's results from another species (mouse) showing no increase in the area of lung hemorrhage using a different contrast agent (Albunex) when exposed to pulsed ultrasound. [Work supported by NIH Grant No. R01EB02641.

O'Brien, William D.; Simpson, Douglas G.; Frizzell, Leon A.; Zachary, James F.

2003-10-01

44

Focused attention and the detectability of weak gustatory stimuli. Empirical measurement and computer simulations.  

PubMed

Attentional processes can modulate the detectability of weak stimuli; for example, the detectability of visual or auditory signals can depend on whether attention is allocated to the appropriate spatial location (vision) or acoustic frequency (hearing). Earlier attempts in the first author's laboratory to find analogous effects of focused attention on the detectability of taste stimuli were equivocal, in part it seems because human gustatory sensitivity can fluctuate substantially over time, a serious problem when using procedures that track sensitivity (d') to a constant stimulus concentration. To circumvent this problem, we adopted an adaptive psychophysical procedure, the transformed up-down method, using a 3-down/1-up rule to determine how the threshold to detect weak concentrations of sucrose and citric acid depended on whether the stimulus presented in a given two-alternative, forced-choice trial was expected or unexpected. The results showed threshold sensitivity to be slightly but consistently poorer when the test stimulus was unexpected (e.g., sucrose presented when citric acid was expected) than it was when the test stimulus was expected (e.g., sucrose presented when sucrose was expected). In this attentional paradigm, the unexpected stimulus must perforce be presented on only a small fraction of the trials. In selecting a procedure, we chose a 3-down/1-up adaptive rule rather than the more popular 2-down/1-up rule, a choice that turned out to be in line with results of Monte Carlo computer simulations. These simulations suggest that across a wide range of conditions (starting stimulus concentrations, step sizes), the variability in threshold measurements can be smaller with a 3-down/1-up rule than with a 2-down/1-up rule, even when the total number of trials is the same and not very great. PMID:9929665

Marks, L E; Wheeler, M E

1998-11-30

45

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

46

Development of a Focus-Reduction Neutralizing test for Detecting Equine Herpesvirus Type-1-Neutralizing Antibodies.  

PubMed

Virus-neutralizing (VN) testing is essential for evaluating virus-specific immunity in equine herpesvirus type-1 (EHV-1) infection. We developed a focus-reduction neutralization test (FRNT) for EHV-1 using 96-well plates for faster large-scale testing with sufficient sensitivity. We used an overlay medium containing Avicel (FMC Biopolymer), a microcrystalline cellulose with lower viscosity than the methylcellulose. The foci were visualized by immuno-staining with anti-EHV-1 gp14 monoclonal antibody. The FRNT successfully detected seroconversion in horses experimentally infected with EHV-1 (n=3) and in those infected naturally (n=16). The FRNT for EHV-1 was high-throughput and time saving. The FRNT can be used in large-scale seroepidemiological studies of EHV-1 and in evaluating vaccine efficacy. PMID:23595119

Bannai, Hiroshi; Nemoto, Manabu; Tsujimura, Koji; Yamanaka, Takashi; Kondo, Takashi; Matsumura, Tomio

2013-04-16

47

Flux-focusing eddy current probe and method for flaw detection  

NASA Astrophysics Data System (ADS)

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 is presented. 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.; Clendenin, C. Gerald

1993-10-01

48

Determination of arsenic in seafood by focused microwave digestion and hydride generation-atomic fluorescence detection.  

PubMed

A new method was developed for total arsenic determination in seafood products such as oysters, mussels, tuna fish, and algae. Matrix decomposition and oxidation to arsenate of all the arsenic compounds in the product were completed in 25 min by using a 3-step program of focused microwaves (40-120 W) with nitric and sulfuric acids. Quantitation was performed by hydride generation-atomic fluorescence detection (HG-AFS). Results of method optimization are presented and discussed. A detection limit <125 microg/kg arsenic was obtained; the quantitation limit was close to 400 microg/kg, with repeatability and reproducibility <5% relative standard deviation. Validation was performed by analyzing 4Reference Materials (arsenic concentration expressed as mg/kg): The National Institute of Standards and Technology SRM 1566a Oyster tissue (14.0 +/- 1.2); the Bureau Community of Reference (now Standard Measurements & Testing Program) CRM 278 Mussel tissue (5.9 +/- 0.2) and CRM 627 Tuna fish (4.8 +/- 0.3); and the International Atomic Energy Agency RM 140 Fucus sample (44.3 +/- 2.1). PMID:11324624

Vilanó, M; Rubio, R

49

High-efficiency molecular counting in solution: Single-molecule detection in electrodynamically focused microdroplet streams  

SciTech Connect

We report fluorescence detection of individual rhodamine 6G molecules using a linear quadrupole to focus streams of microdroplets through the waist of a counterpropagating cw Ar{sup +} laser. Since the terminal velocity scales as the square of the droplet diameter, the droplet-laser interaction time was `tunable` between 5 and 200 ms by using water samples spiked with a small, variable (2-5% v/v) amount of glycerol. Fluorescence bursts from droplets containing single molecules were clearly distinguished from the blanks in real time with an average signal-to-noise ratio of about 10, limited primarily by photobleaching and droplet size fluctuations (<1%). The volume throughput rates associated with this approach (approx. 10 pL/s) are roughly 10{sup 3} higher than those associated with particle levitation techniques, with minimal sacrifice in sensitivity. Total molecular detection efficiencies of about 80% (at >99% confidence) were obtained for 100 and 15 fM rhodamine 6G solutions, in good agreement with detailed theoretical calculations and statistical limitations. 39 refs., 7 figs., 1 tab.

Lermer, N.; Barnes, M.D.; Kung, C.Y.; Whitten, W.B.; Ramsey, J.M. [Oak Ridge National Lab., TN (United States)

1997-06-01

50

Isoelectric point determination of live polioviruses by capillary isoelectric focusing with whole column imaging detection.  

PubMed

Using a capillary isoelectric focusing-whole column imaging detection (CIEF-WCID) method, the isoelectric points (pI) of complete intact polioviruses were determined. The polioviruses that were analyzed are the commonly used viruses for the production of inactivated polio vaccines (IPV)-Mahoney (type 1), MEF (type 2), and Saukett (type 3)-as well as for attenuated oral polio vaccines (OPV) and Sabin types 1, 2, and 3. A method for analyzing biological hazardous components (biological safety level 2) was set up for the CIEF-WCID analyzer used. This method is based on closed circuits. The determined pI's were 6.2 for Mahoney, 6.7 for MEF-1, and 5.8 for Saukett. The pI's of Sabin types 1, 2, and 3 viruses were 7.4, 7.2, and 6.3, respectively. Resolution of the virus peaks was shown to be reproducible. Using this adjusted CIEF-WCID technique, the pI of biologically hazardous components like toxins or viruses can be determined, which is beneficial for the development of vaccine production methods among others. PMID:23672432

Thomassen, Yvonne E; van Eikenhorst, Gerco; van der Pol, Leo A; Bakker, Wilfried A M

2013-05-28

51

On the detection of functional and structural enzyme mutants by coordinated affinity chromatography and isoelectric focusing  

Microsoft Academic Search

A method of studying structural and functional heterogeneity of enzymes has been developed and tested on chymotrypsin. The enzyme, prepared from single mouse pancreata, has been fractionated with respect to function and charge content by a combination of affinity chromatography and isoelectric focusing. By comparing chymotrypsin isolated from isogenic strains, chymotrypsinogen of strains A\\/Sn and NZB was found to be

Herman Amnéus

1976-01-01

52

Dynamics of ultrasound-induced cavitation bubbles in non-Newtonian liquids and near a rigid boundary  

NASA Astrophysics Data System (ADS)

The dynamics of ultrasound-induced cavitation bubbles situated in non-Newtonian liquids and near a rigid boundary are investigated experimentally by acoustic measurements and high-speed photography with up to 4 million frames/s. The non-Newtonian liquids consist of a 0.5% polyacrylamide (PAM) aqueous solution with a strong elastic component and a 0.5% carboxymethylcellulose aqueous solution with a weak elastic component. The maximum velocity of the re-entrant liquid jet and the pressure amplitude of the acoustic transients emitted during first bubble collapse are diminished by the polymer additives. The most significant reduction was found in the elastic PAM solution. It might be caused by an increased resistance to extensional flow which is conferred upon the liquid by the polymer additive. The results are discussed with respect to the mechanisms of cavitation erosion of rigid materials. The material presented may also be useful for comparison with future numerical work.

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

2004-07-01

53

Radiation force imaging for detection of irreversible changescaused by high intensity focused ultrasound therapy  

Microsoft Academic Search

Therapy monitoring based on echo-time-shift imaging during high intensity focused ultrasound (HIFU) treatment was described. The echo shift estimated by radio frequency (RF) correlation between adjacent frames is potentially useful for mapping coagulation and tissue temperature. B-mode images are also useful for real-time monitoring, but cannot show the denatured region formed below the boiling point. Echo-shift images are, however, can.

Takashi Azuma; Kazuaki Sasaki; Ken-ichi Kawabata; Shin-ichiro Umemura

2005-01-01

54

Focused Ion Beam Deposited Mass Detection using Piezoelectrically- actuated Active Probes  

Microsoft Academic Search

Using focused ion beam deposition, small masses in order of pico-gram are added or removed from piezoelectrically-actuated Active Probes. Active Probes are being increasingly utilized as an attractive alternative to bulky laser-based or piezoresistive-based transduction techniques. Along this line, this study undertakes the frequency response analysis of this system in order to determine the amount of mass on the probe.

Calvin Bradley; S. Nima Mahmoodi; Nader Jalili; Maren Mueller; Ruediger Berger

55

Unsolved problems in early breast cancer detection: Focus on the underserved  

Microsoft Academic Search

Summary In the last decade, numerous research and programmatic efforts have attempted to improve cancer screening practices among women from diverse race\\/ethnic backgrounds on the assumption that observed differences in breast cancer survival were largely due to differences in early detection practices. Recent data from the 1992 National Health Interview Survey and a 1992 survey in San Francisco Bay Area

Robert A. Hiatt; Rena J. Pasick

1996-01-01

56

Real-Time Detection Of Multiple Lesions During High Intensity Focused Ultrasound (HIFU) Treatments  

Microsoft Academic Search

This work describes the development of a non-invasive real-time technique to detect changes in tissue caused by the production of multiple lesions during a HIFU treatment sequence. It is based on estimation of relative changes in tissue properties derived from backscattered RF data, such as speed of sound, density, absorption coefficient, backscattering power, etc., as a function of HIFU exposure.

Ralf Seip; Jahangir Tavakkoli; Adam Wunderlich; Narendra T. Sanghvi; Kris A. Dines; Lawrence A. Crum

2002-01-01

57

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

PubMed Central

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

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

2007-01-01

58

Capillary Array Isoelectric Focusing With Laser Induced Fluorescence Detection: Milli-pH Unit Resolution and Yoctomole Mass Detection Limits in a 32 Channel System  

PubMed Central

We report a multiplexed capillary electrophoresis system employing an array of 32 capillaries with a micromachined sheath flow cuvette as the detection chamber. The sample streams were simultaneously excited with a 473 nm laser beam, and the fluorescence emission was imaged on a CCD camera with a pair of doublet achromat lens. The instrument produced mass detection limits of 380 ± 120 yoctomoles for fluorescein in zone electrophoresis. Capillary isoelectric focusing of fluorescent standards produced peaks with an average width of 0.0029 ± 0.0008 pH. Capillary coating stability limits the reproducibility of the analysis.

Dada, Oluwatosin O.; Ramsay, Lauren M.; Dickerson, Jane A.; Cermak, Nathan; Jiang, Rong; Zhu, Cuiru; Dovichi, Norman J.

2011-01-01

59

Ultrasound-induced cavitation enhances the delivery and therapeutic efficacy of an oncolytic virus in an in vitro model.  

PubMed

We investigated whether ultrasound-induced cavitation at 0.5 MHz could improve the extravasation and distribution of a potent breast cancer-selective oncolytic adenovirus, AdEHE2F-Luc, to tumour regions that are remote from blood vessels. We developed a novel tumour-mimicking model consisting of a gel matrix containing human breast cancer cells traversed by a fluid channel simulating a tumour blood vessel, through which the virus and microbubbles could be made to flow. Ultrasonic pressures were chosen to maximize either broadband emissions, associated with inertial cavitation, or ultraharmonic emissions, associated with stable cavitation, while varying duty cycle to keep the total acoustic energy delivered constant for comparison across exposures. None of the exposure conditions tested affected cell viability in the absence of the adenovirus. When AdEHE2F-Luc was delivered via the vessel, inertial cavitation increased transgene expression in tumour cells by up to 200 times. This increase was not observed in the absence of Coxsackie and Adenovirus Receptor cell expression, discounting sonoporation as the mechanism of action. In the presence of inertial cavitation, AdEHE2F-Luc distribution was greatly improved in the matrix surrounding the vessel, particularly in the direction of the ultrasound beam; this enabled AdEHE2F-Luc to kill up to 80% of cancer cells within the ultrasound focal volume in the gel 24 hours after delivery, compared to 0% in the absence of cavitation. PMID:21982902

Bazan-Peregrino, Miriam; Arvanitis, Costas D; Rifai, Bassel; Seymour, Leonard W; Coussios, Constantin-C

2011-10-01

60

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

PubMed

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 × 10(9) cm(-2)); sensitivity to impacts at grazing angle incidence; and better definition of the lateral interaction volume in target materials. PMID:24113400

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

2013-10-11

61

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

62

A tissue phantom for visualization and measurement of ultrasound-induced cavitation damage  

PubMed Central

Many ultrasound studies involve the use of tissue-mimicking materials to research phenomena in-vitro and predict in-vivo bioeffects. We have developed a tissue phantom to study cavitation-induced damage to tissue. The phantom consists of red blood cells suspended in an agarose hydrogel. The acoustic and mechanical properties of the gel phantom were found to be similar to soft tissue properties. The phantom’s response to cavitation was evaluated using histotripsy. Histotripsy causes breakdown of tissue structures by generation of controlled cavitation using short, focused, high-intensity ultrasound pulses. Histotripsy lesions were generated in the phantom and kidney tissue using a spherically focused 1-MHz transducer generating 15 cycle pulses at a pulse repetition frequency of 100 Hz with a peak negative pressure of 14 MPa. Damage appeared clearly as increased optical transparency of the phantom due to rupture of individual red blood cells. The morphology of lesions generated in the phantom was very similar to that generated in kidney tissue, at both macroscopic and cellular levels. Additionally, lesions in the phantom could be visualized as hypoechoic regions on a B-Mode ultrasound image, similar to histotripsy lesions in tissue. High speed imaging of the optically-transparent phantom was used to show that damage coincides with the presence of cavitation. These results indicate that the phantom can accurately mimic the response of soft tissue to cavitation and provide a useful tool for studying damage induced by acoustic cavitation.

Maxwell, Adam D.; Wang, Tzu-Yin; Yuan, Lingqian; Duryea, Alexander P.; Xu, Zhen; Cain, Charles A.

2010-01-01

63

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.

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

2011-01-01

64

Threshold Estimation and Superthreshold Behavior of Ultrasound-induced Lung Hemorrhage in Rats: Role of Age Dependency  

PubMed Central

Age-dependent threshold and superthreshold behaviors of ultrasound-induced lung hemorrhage were investigated with one hundred ten 12.6±0.8-day-old rats, one hundred ten 22.9±0.8-day-old rats, and one hundred 57.7±3.9-day-old rats. Exposure conditions were: 2.8 MHz, 10-s exposure duration, 1-kHz pulse repetition frequency and 1.3-?s pulse duration. The in situ (at the pleural surface) peak rarefactional pressure (pr(insitu)) ranged between 1.4 and 10.8 MPa for which there were either 9 or 10 acoustic pressure groups for each of the three rat ages (10 rats/exposure group). For each of the three rat ages there were also shams; there were no lesions in the shams. The pr(insitu) levels were randomized within each age group; rat age was not randomized. Individuals involved in animal handling, exposure, and lesion scoring were blinded to the exposure condition. In addition, one hundred fifty six 72-day-old rats were included from three completed studies (same experimental conditions) to provide a fourth age group for the analysis. Probit regression analysis was used to examine the dependence of the occurrence of lesions on pr(insitu) in the four age groups. Likewise, lesion depth and lesion root surface area were analyzed using Gaussian tobit regression analysis. Although pr(insitu) was a significant variable, no significant age dependence of the pr(insitu) effect was found. Furthermore, age had no significant effect on either the rate of occurrence or the depth of lesions. Given the occurrence of a lesion, a weak age dependence was found for the median surface area of the induced lesion (p-value = 0.037).

O'Brien, William D.; Yang, Yan; Simpson, Douglas G.

2012-01-01

65

Diagnostic ultrasound induced inertial cavitation to non-invasively restore coronary and microvascular flow in acute myocardial infarction.  

PubMed

Ultrasound induced cavitation has been explored as a method of dissolving intravascular and microvascular thrombi in acute myocardial infarction. The purpose of this study was to determine the type of cavitation required for success, and whether longer pulse duration therapeutic impulses (sustaining the duration of cavitation) could restore both microvascular and epicardial flow with this technique. Accordingly, in 36 hyperlipidemic atherosclerotic pigs, thrombotic occlusions were induced in the mid-left anterior descending artery. Pigs were then randomized to either a) ½ dose tissue plasminogen activator (0.5 mg/kg) alone; or same dose plasminogen activator and an intravenous microbubble infusion with either b) guided high mechanical index short pulse (2.0 MI; 5 usec) therapeutic ultrasound impulses; or c) guided 1.0 mechanical index long pulse (20 usec) impulses. Passive cavitation detectors indicated the high mechanical index impulses (both long and short pulse duration) induced inertial cavitation within the microvasculature. Epicardial recanalization rates following randomized treatments were highest in pigs treated with the long pulse duration therapeutic impulses (83% versus 59% for short pulse, and 49% for tissue plasminogen activator alone; p<0.05). Even without epicardial recanalization, however, early microvascular recovery occurred with both short and long pulse therapeutic impulses (p<0.005 compared to tissue plasminogen activator alone), and wall thickening improved within the risk area only in pigs treated with ultrasound and microbubbles. We conclude that although short pulse duration guided therapeutic impulses from a diagnostic transducer transiently improve microvascular flow, long pulse duration therapeutic impulses produce sustained epicardial and microvascular re-flow in acute myocardial infarction. PMID:23922797

Xie, Feng; Gao, Shunji; Wu, Juefei; Lof, John; Radio, Stanley; Vignon, Francois; Shi, William; Powers, Jeffry; Unger, Evan; Everbach, E Carr; Liu, Jinjin; Porter, Thomas R

2013-07-29

66

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.

2011-01-01

67

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

68

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.

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

2013-01-01

69

Detection systems for mass spectrometry imaging: a perspective on novel developments with a focus on active pixel detectors.  

PubMed

Instrumental developments for imaging and individual particle detection for biomolecular mass spectrometry (imaging) and fundamental atomic and molecular physics studies are reviewed. Ion-counting detectors, array detection systems and high mass detectors for mass spectrometry (imaging) are treated. State-of-the-art detection systems for multi-dimensional ion, electron and photon detection are highlighted. Their application and performance in three different imaging modes--integrated, selected and spectral image detection--are described. Electro-optical and microchannel-plate-based systems are contrasted. The analytical capabilities of solid-state pixel detectors--both charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS) chips--are introduced. The Medipix/Timepix detector family is described as an example of a CMOS hybrid active pixel sensor. Alternative imaging methods for particle detection and their potential for future applications are investigated. PMID:23239313

Jungmann, Julia H; Heeren, Ron M A

2013-01-15

70

Detection of imaging acoustic signals for synchronizing a commercial ultrasound imager with a high intensity focused ultrasound therapy system  

Microsoft Academic Search

Transcutaneous surgical procedures performed with a high intensity focused ultrasound (HIFU) therapy system can be monitored in real-time with an ultrasound imaging system if the HIFU is gated appropriately. Without synchronization, gated or continuous HIFU saturates the imaging system and interference occludes the image. If a gating signal is synchronized with the imaging cycle from any commercial imager, the location

Neil R. Owen; Michael R. Bailey; Peter J. Kaczkowski; Wayne Kreider; Lawrence A. Crum

2004-01-01

71

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

Microsoft Academic Search

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

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

1998-01-01

72

Studies on a Heat-Labile Variola Virus Inhibitor in Normal Sera. I. Detection by the Variola Focus Reduction Assay and its General Characteristics  

Microsoft Academic Search

Summary A heat-labile inhibitor (HLI) capable of neutralizing the infectivity of variola virus, as measured by reduction of focus-forming and plaque-forming activity, was detected in normal human, guinea pig, rabbit and monkey sera. HLI lost its activity on incubation at 56° for 30 min, and showed different behaviors from complement in heat inactivation curves as well as in specific absorption

Takashi Kitamura; Yoshiko Miyagawa; Yukië Tanaka

1973-01-01

73

Detection of a high-endemic focus of Echinococcus multilocularis in red foxes in southern Denmark, January 2013.  

PubMed

The Danish surveillance programme for Echinococcus multilocularis was initiated in September 2011, and so far 679 wild carnivores have been examined. In April 2012, one infected fox was detected in Højer near the Danish-German border, and in January 2013 three additional foxes from the same area were found infected. Local prevalence in the area was 31% (four of 13 foxes) which is a new epidemiological situation calling for reevaluation of the national risk management. PMID:23515060

Enemark, H L; Al-Sabi, M N; Knapp, J; Staahl, M; Chríel, M

2013-03-07

74

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

Microsoft Academic Search

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

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

2004-01-01

75

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.

76

First detection of Leishmania infantum DNA in wild caught Phlebotomus papatasi in endemic focus of cutaneous leishmaniasis, South of Iran  

PubMed Central

Objective To identify the vectors and reservoirs of cutaneous leishmaniasis in the endemic focus of Farashband, Fars Province, South of Iran. Methods Sticky papers and Sherman trap were used for collection of sand flies and rodents, respectively. Polymerase chain reaction (PCR) of kDNA, ITS1-rDNA were used for identification of Leishmania parasite in sand flies as well as rodents. Results Totally 2?010 sand flies were collected and the species of Phlebotomus papatasi Scopoli was the common specimen in outdoors and indoors places. PCR technique was employed on 130 females of Phlebotomus papatasi. One of them (0.76%) was positive to parasite Leishmania major (L. major) and one specimen (0.76%) was positive to Leishmania infantum. Microscopic investigation on blood smear of the animal reservoirs for amastigote parasites revealed 16 (44%) infected Tatera indica. Infection of them to L. major was confirmed by PCR against kDNA loci of the parasite. Conclusions The results indicated that Phlebotomus papatasi was the dominant species circulating two species of parasites including L. major and Leishmania infantum among human and reservoirs. Furthermore, Tatera indica is the only main host reservoir for maintenance of the parasite source in the area.

Yavar, Rassi; Hadi, Karami; Reza, Abai Mohammad; Mohebali, M; Hasan, Bakshi; Ali, Oshaghi Mohammad; Sina, Rafizadeh; Habib, Bagherpoor Hagigi; Abodolrahim, Hosseini; Manuchehr, Gholami

2013-01-01

77

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

Microsoft Academic Search

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

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

2012-01-01

78

Enhancement effect of ultrasound-induced microbubble cavitation on branched polyethylenimine-mediated VEGF(165) transfection with varied N/P ratio.  

PubMed

One isoform of the vascular endothelial growth factor, VEGF(165), has been reported to be a dominant mediator and regulator of angiogenic process, which plays an important role in treating cardiovascular diseases and chronically ischemic wounds. Branched polyethylenimine (bPEI) has been widely used as a non-viral delivery vector for gene therapy. Although bPEI-mediated DNA transfection efficiency can be raised by increasing the PEI nitrogen:DNA phosphate (N/P) ratio, cytotoxicity increases as well. In this study, the enhancement effect of microbubble inertial cavitation (IC) on bPEI-mediated VEGF(165) transfection was investigated, in an effort to optimize transfection efficiency using low N/P ratios. HEK 293T cells, mixed with bPEI:VEGF(165) complexes, were exposed to 1-MHz ultrasound pulses. The results show that: (1) IC activity induced by microbubble destruction can be quantified as an IC "dose" (ICD) and will increase with increasing acoustic driving pressure; (2) larger sonoporation pores can be generated by increasing ICD; (3) the transfection efficiency can be enhanced by increasing ICD until reaching a saturation level; and (4) microbubble IC activity has less cytotoxicity than bPEI, although a combinatorial effect of microbubble IC activity and bPEI could be observed on cell viability. The results suggest that, with appropriate ultrasound parameters, it is possible to optimize bPEI-mediated VEGF transfection efficiency using relatively low N/P ratios by employing ultrasound-induced microbubble inertial cavitation. PMID:23141903

Zhang, Chun-Bing; Cao, Hui-Lin; Li, Qian; Tu, Juan; Guo, Xiasheng; Liu, Zheng; Zhang, Dong

2012-11-08

79

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

2013-03-28

80

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

PubMed Central

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

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

2013-01-01

81

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

82

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.

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

83

The Dependence of the Ultrasound-Induced Blood-Brain Barrier Opening Characteristics on Microbubble Size In Vivo  

NASA Astrophysics Data System (ADS)

Recent neuropharmaceutical developments have led to potent disease-modifying drugs. In spite of these advancements, most agents cannot traverse the blood-brain barrier (BBB) and deposit in the brain. Focused ultrasound (FUS) with microbubbles has been shown to induce noninvasive, localized, and transient BBB opening. Although promising, safety and efficacy concerns still remain. Previously reported experiments used conventional imaging contrast agents that have a wide size distribution. In this study, we hypothesize that BBB opening characteristics are dependent on bubble diameter. A 25 ?l bolus of in-house manufactured, lipid-shelled bubbles with either 1-2 or 4-5 ?m diameter ranges was injected intravenously. Pulsed FUS (frequency: 1.5 MHz, peak-negative pressure: 146-607 kPa, duty cycle: 20%, duration: 1-min) was then applied to the left hippocampus of mice (n = 16) in vivo through the intact skin and skull. MRI or fluorescence microscopy was used to determine BBB opening. Contrast-enhanced (Omniscan™ 0.75 mL; molecular weight: 574 Da) MRI (9.4-T) was acquired on multiple days after sonication to determine BBB opening and closing. Fluorescence microscopy was also used to determine the feasibility of delivering large, 3 kDa dextran compounds through the BBB. The BBB opening acoustic pressure threshold for the 4-5?m bubbles was in the 146-304 kPa range while the threshold for the 1-2?m bubbles was higher. In conclusion, FUS-induced BBB opening and closing was shown to be dependent on the bubble diameter indicating the possibility of specifically designing bubbles to enhance this therapeutic application.

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

2009-04-01

84

Ultrasound-induced emulsification of subcritical carbon dioxide/water with and without surfactant as a strategy for enhanced mass transport.  

PubMed

Pulsed ultrasound was used to disperse a biphasic mixture of CO2/H2O in a 1dm(3) high-pressure reactor at 30°C/80bar. A view cell positioned in-line with the sonic vessel allowed observation of a turbid emulsion which lasted approximately 30min after ceasing sonication. Within the ultrasound reactor, simultaneous CO2-continuous and H2O-continuous environments were identified. The hydrolysis of benzoyl chloride was employed to show that at similar power intensities, comparable initial rates (1.6±0.3×10(-3)s(-1) at 95Wcm(-2)) were obtained with those reported for a 87cm(3) reactor (1.8±0.2×10(-3)s(-1) at 105Wcm(-2)), demonstrating the conservation of the physical effects of ultrasound in high-pressure systems (emulsification induced by the action of acoustic forces near an interface). A comparison of benzoyl chloride hydrolysis rates and benzaldehyde mass transport relative to the non-sonicated, 'silent' cases confirmed that the application of ultrasound achieved reaction rates which were over 200 times faster, by reducing the mass transport resistance between CO2 and H2O. The versatility of the system was further demonstrated by ultrasound-induced hydrolysis in the presence of the polysorbate surfactant, Tween, which formed a more uniform CO2/H2O emulsion that significantly increased benzoyl chloride hydrolysis rates. Finally, pulse rate was employed as a means of slowing down the rate of hydrolysis, further illustrating how ultrasound can be used as a valuable tool for controlling reactions in CO2/H2O solvent mixtures. PMID:23791428

Cenci, Steven M; Cox, Liam R; Leeke, Gary A

2013-06-03

85

Focus marking and focus interpretation  

Microsoft Academic Search

The languages of the world exhibit a range of formal phenomena (e.g. accenting, syntactic reordering and morphological marking) that are commonly linked to the information-structural notion of focus. Crucially, there does not seem to be a one-to-one mapping between particular formal features (focus marking devices) and focus, neither from a cross-linguistic perspective, nor within individual languages. This raises the question

Malte Zimmermann; Edgar Onea

2011-01-01

86

Performance assessment of HIFU lesion detection by harmonic motion imaging for focused ultrasound (HMIFU): a 3-D finite-element-based framework with experimental validation.  

PubMed

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 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 and 5.39 and 1.65, 3.19 and 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 found in both simulations (16.2, 73.1 and 334.7 mm(2)) and experiments (26.2, 94.2 and 206.2 mm(2)). 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

2011-10-27

87

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.

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

88

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

89

Particle focusing in microfluidic devices  

Microsoft Academic Search

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

Xiangchun Xuan; Junjie Zhu; Christopher Church

2010-01-01

90

Investigations into ultrasound induced atomization.  

PubMed

The present work deals with measurements of the droplet size distribution in an ultrasonic atomizer using photographic analysis with an objective of understanding the effect of different equipment parameters such as the operating frequency, power dissipation and the operating parameters such as the flow rate and liquid properties on the droplet size distribution. Mechanistic details about the atomization phenomena have also been established using photographic analysis based on the capture of the growth of the instability and sudden ejection of droplets with high velocity. Velocity of these droplets has been measured by capturing the motion of droplets as streaks. It has been observed that the droplet size decreases with an increase in the frequency of atomizer. Droplet size distribution was found to change from the narrow to wider range with an increase in the intensity of ultrasound. The drop size was found to decrease with an increase in the fluid viscosity. The current work has clearly highlighted the approach for the selection of operating parameters for achieving a desired droplet size distribution using ultrasonic atomization and has also established the controlling mechanisms for the formation of droplet. An empirical correlation for the prediction of the droplet size has been developed based on the liquid and equipment operating properties. PMID:22672979

Ramisetty, Kiran A; Pandit, Aniruddha B; Gogate, Parag R

2012-05-11

91

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

92

Focusing techniques  

Microsoft Academic Search

We use the paraxial geometric optics model of image formation to derive a set of camera focusing techniques. These techniques do not require calibration of cameras but involve a search of the camera parameter space. The techniques are proved to be theoretically sound under weak assumptions. They include energy maximization of unfiltered, low-pass-filtered, high-pass-filtered, and bandpass-filtered images. It is shown

Murali Subbarao; Tae S. Choi; Arman Nikzad

1993-01-01

93

Evaluation of PCR procedures for detecting and quantifying Leishmania donovani DNA in large numbers of dried human blood samples from a visceral leishmaniasis focus in Northern Ethiopia  

PubMed Central

Background Visceral Leishmaniasis (VL) is a disseminated protozoan infection caused by Leishmania donovani parasites which affects almost half a million persons annually. Most of these are from the Indian sub-continent, East Africa and Brazil. Our study was designed to elucidate the role of symptomatic and asymptomatic Leishmania donovani infected persons in the epidemiology of VL in Northern Ethiopia. Methods The efficacy of quantitative real-time kinetoplast DNA/PCR (qRT-kDNA PCR) for detecting Leishmania donovani in dried-blood samples was assessed in volunteers living in an endemic focus. Results Of 4,757 samples, 680 (14.3%) were found positive for Leishmania k-DNA but most of those (69%) had less than 10 parasites/ml of blood. Samples were re-tested using identical protocols and only 59.3% of the samples with 10 parasite/ml or less were qRT-kDNA PCR positive the second time. Furthermore, 10.8% of the PCR negative samples were positive in the second test. Most samples with higher parasitemias remained positive upon re-examination (55/59 =93%). We also compared three different methods for DNA preparation. Phenol-chloroform was more efficient than sodium hydroxide or potassium acetate. DNA sequencing of ITS1 PCR products showed that 20/22 samples were Leishmania donovani while two had ITS1 sequences homologous to Leishmania major. Conclusions Although qRT-kDNA PCR is a highly sensitive test, the dependability of low positives remains questionable. It is crucial to correlate between PCR parasitemia and infectivity to sand flies. While optimal sensitivity is achieved by targeting k-DNA, it is important to validate the causative species of VL by DNA sequencing.

2013-01-01

94

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

95

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

Microsoft Academic Search

The aim of this study was to compare detection of non-cavitated approximal caries lesions in images from seven solid-state\\u000a intraoral digital receptors, with particular focus on two task-specific enhancement filters. One hundred and sixty approximal\\u000a non-cavitated surfaces were radiographed under standardized conditions using the following seven intraoral solid-state digital\\u000a receptors: two CMOS systems, Schick CDR-APS, and Kodak RVGui; and five

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

2008-01-01

96

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

97

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

PubMed

Reducing the capacity of a victim to react against sexual assault, coupled with a possible abrupt unconsciousness-inducing effect and ease of administration in spiked drinks, have resulted in the use of sedative agents in cases of drug-facilitated offence. Among these compounds, tetrazepam may impair an individual rapidly. The chances of detecting this substance increase if the most sensitive methods are used and if the biologic matrix that allows the longest possible detection time is available. To document the window of detection of tetrazepam, 50 mg of the drug was administered orally to 2 volunteers, and the following samples were collected: oral fluid (n = 1) over 515 minutes, urine (n = 2) over 236-240 hours, hair (n = 2) 4 weeks after exposure, and beard (n = 1) over 34 days. Tetrazepam was analyzed by LC-MS/MS (Micromass Quattro Micro) after alkalinization and extraction by dichloromethane/diethyl ether in the presence of diazepam-d5, used as internal standard. Reversed-phase separation on an XTerra MS C18 column was achieved in 12 minutes, under gradient conditions. Pseudo-molecular ions selected were m/z 289.2 and 290.2 for tetrazepam and the internal standard (IS), respectively, and the corresponding daughter ions selected were m/z 225.2 and 253.2 for tetrazepam and m/z 154.1 and 198.3 for the IS. Urine tested positive for tetrazepam over 236-240 hours (14-13 ng/mL). Oral fluid tested positive for tetrazepam over 515 minutes (2.5 ng/mL). Tetrazepam was detected in beard over 27 days (6.5 pg/mg). A single tetrazepam dose was detected in hair 4 weeks after intake (123-175 pg/mg). Tetrazepam tested positive over the studied time intervals but would be expected to be detectable for a considerably longer time. Therefore, in cases of drug-facilitated crimes in which tetrazepam is involved, hair and beard analyses can be an important complement to urine analyses to document exposure, particularly if LC-MS/MS is used. PMID:16175127

Concheiro, Marta; Villain, Marion; Bouchet, Stéphane; Ludes, Bertrand; López-Rivadulla, Manuel; Kintz, Pascal

2005-10-01

98

Performance of the Focus HerpeSelect-2 EIA for the detection of herpes simplex virus type 2 antibodies in seven African countries  

PubMed Central

Objective To compare the performance of the Focus HerpeSelect-2 enzyme immunoassay (EIA) to the gold standard HSV-2 Western blot, among HIV-1 uninfected men and women in East and Southern Africa. Methods 3399 HIV-1 uninfected women and men from 7 countries in East and Southern Africa were tested for HSV-2 antibody using Focus HerpeSelect-2 EIA. The performance of the HerpesSelect-2 EIA was compared with the gold standard HSV-2 specific Western blot. Results Two-thirds (2294/3399) of participants were male and two-thirds (2242/3399) were from East Africa. By Western blot testing, HSV-2 prevalence was 68%, 59% in men and 85% in women. At the manufacturer’s recommended cut-off value of greater than 1.1, the HerpeSelect-2 EIA had a sensitivity of 98.3% and specificity 80.3%. Receiver operating characteristic (ROC) plot analysis indicated that the optimum cut-off was 2.1 or greater with sensitivity 93.9% and specificity 90.5%. Diagnostic accuracy was modestly higher for Southern Africa (AUC=0.979, 95% CI: 0.970-0.988) compared with East Africa (AUC=0.954, 95% CI: 0.942-0.965; p<0.001 for Southern vs. East Africa). Conclusions The Focus HerpeSelect-2 EIA has acceptable diagnostic accuracy for determination of HSV-2 serostatus in African HIV-1 uninfected adults. An assay cut-off value of 2.1 or greater results in approximately 90% sensitivity and specificity, against a gold standard HSV-2 Western blot. Diagnostic accuracy differed slightly by geographical region.

Mujugira, Andrew; Morrow, Rhoda Ashley; Celum, Connie; Lingappa, Jairam; Delany-Moretlwe, Sinead; Fife, Kenneth H.; Heffron, Renee; De Bruyn, Guy; Homawoo, Brigitte; Karita, Etienne; Mugo, Nelly; Vwalika, Bellington; Baeten, Jared M.

2011-01-01

99

Determination of BAY 12-8039, a new 8-methoxyquinolone, in human body fluids by high-performance liquid chromatography with fluorescence detection using on-column focusing  

Microsoft Academic Search

A reversed-phase (RP) high-performance liquid chromatographic (HPLC) method with fluorescence detection allowing the sensitive and specific quantification of BAY 12-8039, a new antimicrobially active 8-methoxyquinolone, in biological fluids is described. The method is compared to a microbiological assay (bioassay) based on B. subtilis test strain with a limit of quantification of approximately 60 ?g\\/l. Following dilution and centrifugation, plasma, saliva

H. Stass; A. Dalhoff

1997-01-01

100

Detecting \\  

Microsoft Academic Search

This paper investigates the effects of observing windows on detecting\\u000atransiting planets by calculating the fraction of planets with a given period\\u000athat have zero, one (single), two (double), or $\\\\ge$3 (multiple) transits\\u000aoccurring while observations are being taken. We also investigate the effects\\u000aof collaboration by performing the same calculations with combined observing\\u000atimes from two wide-field transit survey

S. W. Fleming; S. R. Kane; P. R. McCullough; F. R. Chromey

2008-01-01

101

Science In Focus: Energy  

NSDL National Science Digital Library

The interviewee comments on Jimmy Carter's speech which equated energy conservation with deprivation. The interviewee disagrees and believes that energy conservation does not require one to do without, but rather to do smartly. He gives some specific examples, including hybrid cars, and hotel key cards in China that enable the outlets and lights (and disable the outlets and lights when you leave with your key.) He goes on to explain three types of energy efficiency: conventional (ex. using more efficient light bulbs), operational efficiency (ex. using a sensor to detect if a person is in the room and needs light), and behavioral efficiency (ex. person deciding to turn off the light). Lastly, he provides a specific example of behavior efficiency operating on a statewide level, a 5% drop in electricity use in California following the energy crisis of 2001. This segment focuses on the first half of the benchmark.

Astrophysics, Harvard-Smithsonian C.

102

Usefulness of the rK39-Immunochromatographic Test, Direct Agglutination Test, and Leishmanin Skin Test for Detecting Asymptomatic Leishmania Infection in Children in a New Visceral Leishmaniasis Focus in Amhara State, Ethiopia  

PubMed Central

In areas where visceral leishmaniasis is anthroponotic, asymptomatically infected patients may play a role in transmission. Additionally, the number of asymptomatic patients in a disease-endemic area will also provide information on transmission dynamics. Libo Kemkem and Fogera districts (Amhara State, Ethiopia) are now considered newly established areas to which visceral leishmaniasis is endemic. In selected villages in these districts, we conducted a study to assess the usefulness of different approaches to estimate the asymptomatic infection rate. Of 605 participants, the rK39 immunochromatographic test was able to detect asymptomatic infection in 1.5% (9 of 605), direct agglutination test in 5.3% (32 of 605), and leishmanin skin test in 5.6% (33 of 589); the combined use of serologic methods and leishmanin skin test enabled detecting asymptomatic infection in 10.1% (61 of 605). We conclude that the best option to detect asymptomatic infection in this new visceral leishmaniasis–endemic focus is the combined use of the direct agglutination test and the leishmanin skin test.

Gadisa, Endalamaw; Custodio, Estefania; Canavate, Carmen; Sordo, Luis; Abebe, Zelalem; Nieto, Javier; Chicharro, Carmen; Aseffa, Abraham; Yamuah, Lawrence; Engers, Howard; Moreno, Javier; Cruz, Israel

2012-01-01

103

Laser-2 focus velocimetry  

NASA Astrophysics Data System (ADS)

A review is given of various publications about L2F-velocimetry. Main emphasis is placed upon the important new advances of this technique. The manner of statistical data analysis of turbulent flows including the simplified version which enables a time-saving measuring procedure is described in some detail. The influence of beam diameter - beam separation ratio on the measuring accuracy and on the measuring time is treated. The capability of the L2F-system at close-to-wall measurements could be further improved. Results of measurements in a very small flow channel and in a small turbocharger compressor rotor are presented. The 3-D version of the L2F-system was successfully operated recently. The principle, the optical set-up and the signal processing are described and some first results are presented. A comparison between Laser Doppler (LD) - and Laser 2 Focus (L2F) velocimeters gives answers about such signal properties as amplitude and rate, the smallest detectable particles and about the measuring time needed, based on the probe volume dimensions.

Schodl, R.

1986-11-01

104

Focus group workshop  

Microsoft Academic Search

This highly interactive workshop reviews the theory and practice of focus group methods, and shows how technical communicators can use focus groups to understand the issues and needs of audiences, users, and customers. The workshop covers focus group theory, design considerations, capturing and analyzing data, and validating data through member checking.

James Conklin; George Hayhoe

2010-01-01

105

Focusing solar heat collector  

SciTech Connect

A focusing solar heat collector comprises a light reflective corrugated base surface, a plurality of spaced apart, lighttransmitting conduits positioned in the corrugations of the reflective surface so that light reflected by the reflective surface is focused on the conduits, and an organic black liquid of high boiling point circulated through the conduits to receive the focused solar light.

Fries, J.E.

1982-04-20

106

Using Focus Group Interviews.  

ERIC Educational Resources Information Center

|Examines focus groups from a performance technology perspective, describes the focus group process, and discusses uses and misuses. Suggests that due to the depth and accuracy of insights revealed, focus groups have potential to aid performance technologists in their analyses of performance deficiencies as well as their formative and summative…

Subramony, Deepak Prem; Lindsay, Nathan; Middlebrook, Rebecca H.; Fosse, Chuck

2002-01-01

107

Ultrasound-induced nanofragmentation of bubbles  

NASA Astrophysics Data System (ADS)

Micron-sized bubbles are of considerable interest for use in biomedical imaging and drug delivery. Lipid-coated bubbles have been reported to rapidly shrink in the presence of short (3 ?s) ultrasound pulses, purportedly by shedding of the coat during compression. Loss of coat would increase the internal pressure, enhancing diffusive gas loss long after the pulse. Note that during such a short pulse, diffusive gas loss is insignificant. If lipid-shedding is the mechanism for bubble shrinkage, a coated bubble in ultrasound may shrink no faster than a quiescent uncoated bubble; the shrinkage rate is entirely dominated by diffusive loss between pulses. Remarkably, we find that most insonated lipid-coated bubbles do shrink faster than quiescent uncoated bubbles. If bubbles cannot shrink by diffusive gas loss, they must fragment, though no fragmentation was observed. The results are consistent with ``nanofragmentation,'' where sub-micron fragments (which entrap gas) are lost from the bubble. Entrapment of gas in fragments may have important consequences for their efficacy in ultrasound-mediated drug delivery, and could affect their ability to transfer drugs to cells.

Cox, Debra; Thomas, James

2011-10-01

108

Use of stationary focused ultrasound fields for characterization of tissue and localized tissue ablation  

NASA Astrophysics Data System (ADS)

Ultrasound-induced blood stasis has been observed for more than 30 years. The physical understanding of the phenomenon has not been fully explored. Analytical descriptions of the acoustic interaction with spheres in suspension have been derived but the physical implications and limitations have not been demonstrated. The analytical expressions will be tested against physical observations using numerical simulations. The simulations will begin with stationary spheres and continue with the inclusion of moving spheres and a moving suspending fluid. To date, experimental observations of acoustically induced blood stasis have been either in vitro or invasive. We demonstrate ultrasound-induced blood stasis in murine normal leg muscle versus tumor-bearing legs, observed through noninvasive measurements of optical spectroscopy, and discuss possible diagnostic uses for this effect of ultrasound. We derive the optimal optical wavelengths for measuring the effects of the ultrasound at small source detector separations. Using optical oximetry performed at the optimal wavelengths, we demonstrate that effects of ultrasound can be used to differentiate tumor from normal leg muscle tissue in mice. To provide a statistical analysis of the experiments, we propose a novel diagnostic algorithm that quantitatively differentiates tumor from nontumor with maximum specificity 0.83, maximum sensitivity 0.79, and area under receiver-operating-characteristics curve 0.90. Ultrasound has long been known to cause tissue heating when applied in high intensities. More recently, interest has arisen in the area of High Intensity Focused Ultrasound (HIFU) for localized tissue heating effects, specifically thermal ablation. All present techniques employ focused traveling high intensity acoustic waves to create a region of elevated temperature. Such high intensity traveling waves can be damaging to normal tissue in the vicinity of the focal region, and have demonstrated surface burns and caused patient discomfort in certain clinical trials. Use of lower intensity ultrasound can minimize the side-effects presented by HIFU. We demonstrate the use of low intensity multiple beam ultrasound resulting in stationary acoustic fields which are capable of heating a very small and more precisely located region of tissue. We simulate the fields formed by traveling waves and stationary waves created by two opposing sources and two orthogonal sources. The simulations are compared to experimental results where the intensity of the individual ultrasound beams is within FDA diagnostic ultrasound limits (0.720 W/cm2). Temperature elevation that would cause cell death was achieved in tissue-mimicking phantoms after short exposures to the acoustic field in the region of beam overlap.

Winey, Brian Andrew

109

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

PubMed

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

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

2008-10-01

110

Foreign Policy In Focus  

NSDL National Science Digital Library

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

111

Happy mood decreases self-focused attention  

Microsoft Academic Search

Research addressing the inè uence of happy mood on self-focused attention has yielded inconsistent results. Some studies found that happy mood decreased self-focus relative to sad mood. Other studies did not detect a signié cant difference between happy and neutral mood, and still other studies found that happy mood, relative to neutral mood, increased self-focus. These investigations have potential shortcomings,

Jeffrey D. Green; Constantine Sedikides; Judith A. Saltzberg; Joanne V. Wood; Lori-Ann B. Forzano

2003-01-01

112

Virtual Synchronous Focus Groups  

Microsoft Academic Search

Background: Traditionally, focus groups have been held as face-to-face meetings with a carefully selected group of participants and a moderator to discuss a topic. With the increasing use of the Internet, message boards, and chat rooms, synchronous and asynchronous virtual focus groups can provide opportunities to collect qualitative information. Objectives: The purpose of this paper is to describe how traditional

Deborah K. Mayer; Stefanie Jeruss; Susan K. Parsons

113

Agreement, Shells, and Focus.  

ERIC Educational Resources Information Center

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

Simpson, Andrew; Wu, Zoe

2002-01-01

114

Focused and distributed attention  

Microsoft Academic Search

Recent studies on attention have emphasized distinctions between focused and distributed attention. Distributed attention has been shown to play a key role in obtaining statistical information or processing global aspects of a scene. In addition to differences in information processing, focused and distributed attention differ in terms of the way they interact with emotions. We review findings that indicate close

Narayanan Srinivasan; Priyanka Srivastava; Monika Lohani; Shruti Baijal

2009-01-01

115

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

116

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

117

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.

118

NICMOS Focus Monitoring  

NASA Astrophysics Data System (ADS)

This program is a version of the standard focus sweep used since cycle 7. It has been modified to go deeper and uses more narrow filters for improved focus determination. For Cycle14 a new source has been added in order to accomodate 2-gyro mode: the open cluster NGC1850. The old target, the open cluster NGC3603, will be used whenever available and the new target used to fill the periods when NGC3603 is not visible. Steps: a Use refined target field positions as determined from cycle 7 calibrations b Use MULTIACCUM sequences of sufficient dynamic range to account for defocus c Do a 17-point focus sweep, +/- 8mm about the PAM mechanical zeropoint for each cameras 1 and 2, in 1.0mm steps. d Use PAM X/Y tilt and OTA offset slew compensations refined from previous focus monitoring/optical alignment activities

Wiklind, Tommy

2006-07-01

119

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

120

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

121

Fast focus field calculations  

NASA Astrophysics Data System (ADS)

We present a method for fast calculation of the electromagnetic field near the focus of an objective with a high numerical aperture (NA). Instead of direct integration, the vectorial Debye diffraction integral is evaluated with the fast Fourier transform for calculating the electromagnetic field in the entire focal region. We generalize this concept with the chirp z transform for obtaining a flexible sampling grid and an additional gain in computation speed. Under the conditions for the validity of the Debye integral representation, our method yields the amplitude, phase and polarization of the focus field for an arbitrary paraxial input field in the aperture of the objective. Our fast calculation method is particularly useful for engineering the point-spread function or for fast image deconvolution. We present several case studies by calculating the focus fields of high NA oil immersion objectives for various amplitude, polarization and phase distributions of the input field. In addition, the calculation of an extended polychromatic focus field generated by a Bessel beam is presented. This extended focus field is of particular interest for Fourier domain optical coherence tomography because it preserves a lateral resolution of a few micrometers over an axial distance in the millimeter range.

Leutenegger, Marcel; Geissbuehler, Matthias; Märki, Iwan; Leitgeb, Rainer A.; Lasser, Theo

2008-02-01

122

NICMOS FOM Focus Test  

NASA Astrophysics Data System (ADS)

This proposal is built to run a NIC3 focus sweep at absolute FOMY positions of 20 and 24 arcsec: given that the default FOM is now 16 arcsec, the FOM mechanism will be moved an additional 4 arcseconds in the first sweep {visit 1}, and an additional 8 arcseconds in the second sweep {visit 2}. The sweeps will move the PAM mechanism from +6.5mm to -9.5mm {The PAM nominal position must first be moved to mechanical 0.0 from it's default mechanical PAM3 setting of -9.5mm to avoid exceeding PAM travel limits of + and - 9664 steps}. A tilt grid sweep will be performed in Visit 3. The PAM will be tilted by +/-8 steps in 2 diagonally-offset 3x3 grids around the PAM "best tilt" position in NIC3 at PAM focus -9.5mm and FOMY position 24 arcsec. The quality of the stellar psf's will be checked to determine optimal PAM tilt values for this FOM and focus setting. This proposal should be scheduled to run AS SOON AS POSSIBLE before 21-MAR-98. Objectives: a} Cover sufficient region of PAM focus space to ensure the optimal locations are included. {NIC3 encircled energy and phase retrieval will be done.} b} Measure image quality at different FOM positions. c} Determine best xtilt, ytilt for FOMY 24 arcsec at current best PAM focus of -9.5mm.

Noll, Keith

1997-12-01

123

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

2013-03-30

124

Fast focus field calculations  

NASA Astrophysics Data System (ADS)

We present a fast calculation of the electromagnetic field near the focus of an objective with a high numerical aperture (NA). Instead of direct integration, the vectorial Debye diffraction integral is evaluated with the fast Fourier transform for calculating the electromagnetic field in the entire focal region. We generalize this concept with the chirp z transform for obtaining a flexible sampling grid and an additional gain in computation speed. Under the conditions for the validity of the Debye integral representation, our method yields the amplitude, phase and polarization of the focus field for an arbitrary paraxial input field on the objective. We present two case studies by calculating the focus fields of a 40 × 1.20 NA water immersion objective for different amplitude distributions of the input field, and a 100 × 1.45 NA oil immersion objective containing evanescent field contributions for both linearly and radially polarized input fields.

Leutenegger, Marcel; Rao, Ramachandra; Leitgeb, Rainer A.; Lasser, Theo

2006-11-01

125

Fast focus field calculations.  

PubMed

We present a fast calculation of the electromagnetic field near the focus of an objective with a high numerical aperture (NA). Instead of direct integration, the vectorial Debye diffraction integral is evaluated with the fast Fourier transform for calculating the electromagnetic field in the entire focal region. We generalize this concept with the chirp z transform for obtaining a flexible sampling grid and an additional gain in computation speed. Under the conditions for the validity of the Debye integral representation, our method yields the amplitude, phase and polarization of the focus field for an arbitrary paraxial input field on the objective. We present two case studies by calculating the focus fields of a 40 x 1.20 NA water immersion objective for different amplitude distributions of the input field, and a 100 x 1.45 NA oil immersion objective containing evanescent field contributions for both linearly and radially polarized input fields. PMID:19529543

Leutenegger, Marcel; Rao, Ramachandra; Leitgeb, Rainer A; Lasser, Theo

2006-11-13

126

Sagittal focusing Laue monochromator  

DOEpatents

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

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

Laser two focus techniques  

NASA Astrophysics Data System (ADS)

The development of the laser two focus velocimetry are reviewed. The fundamentals of this nonintrusive fluid flow velocity measurement technique are described. Emphasis is placed upon the advances of this technique. Results of measurements in a very small flow channel and in a small turbocharger compressor rotor are presented. The influence of beam diameter - beam separation ratio on the measuring accuracy and on the measuring time is treated. A multicolor two dimensional system with selectable beam separation is presented. The laser Doppler and the laser two focus techniques are compared.

Schodl, R.

129

NICMOS Focus Monitoring  

NASA Astrophysics Data System (ADS)

This proposal is used to determine and monitor the optimal focus and tilt settings for all three NICMOS cameras. This proposal is build to run NIC1/2/3 sweeps on a 2-weeks basis. This proposal will start to be executed first week in June and will continue through the entire cycle 7. Objectives: a} Cover sufficient region of PAM focus space to insure the optimal locations are included b} Allow sufficient time {7-10 days} to analyze data and uplink changes when required

Suchkov, Anatoly

1997-12-01

130

Young Children. IDRA Focus.  

ERIC Educational Resources Information Center

This theme issue includes five articles that focus on educational, cognitive, and brain research with implications for early childhood educators, including those who work with limited-English-proficient, minority, and economically disadvantaged children. "Coming to Grips with Reading Instruction at the Early Grades" (Christie L. Goodman) reports…

IDRA Newsletter, 1998

1998-01-01

131

Open focus attention training.  

PubMed

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

Fehmi, Lester G; Shor, Susan B

2013-03-01

132

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.

133

Road to Focused Logistics.  

National Technical Information Service (NTIS)

The Revolution in Military Logistics (RML) and Focused Logistics requires us to view sustainment needs and requirements in a new perspective. Gone are the days when brute force and the sheer mass of materiel and numbers of soldiers can be counted on to ov...

A. C. Harvey

2001-01-01

134

Focus on the President.  

ERIC Educational Resources Information Center

In an interview, the incoming president of the Association of Schools and Colleges of Optometry (ASCO), Thomas L. Lewis, discusses his goals for the association, the challenges facing optometric education in the next decade, cooperation between ASCO and other professional organizations in optometry, his mentors in the profession, his focus as a…

Optometric Education, 1996

1996-01-01

135

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.

136

Focus on Efficient Management.  

ERIC Educational Resources Information Center

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

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

137

Focusing of Macroparticle Projectiles  

Microsoft Academic Search

The electrostatic acceleration of small particles to hyper-velocities is a way to get high temperatures by hypervelocity impact. In order to get fusion these particles should be bunched together in order to check the Lawson criterion. The longitudinal focusing of a beam of macroparticles is discussed in analogy with klystron theory. An ideal potential law and a sinusoidal potential law

Alexandre E. Pozwolski; K. Shinsky; D. A. Phelps; H. Fleischmann; D. M. Woodall; R. V. Lovelace; R. A. Meger

1984-01-01

138

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

139

Strongly Focused Gravitational Waves  

NASA Astrophysics Data System (ADS)

This paper contains a new proof of the formation of trapped spheres, in vacuum spacetimes, by the focusing of gravitational waves, from generic data. The first such result was obtained by Christodoulou (Zurich: Eur Math Soc, 2009). We exploit the same physical mechanism, but give a logically independent construction of these spacetimes.

Reiterer, Michael; Trubowitz, Eugene

2011-10-01

140

Focus on Bilingual Education.  

ERIC Educational Resources Information Center

|This collection of essays focuses on issues in bilingual education. First, Elizabeth Flynn examines different kinds of bilingual programs; efforts made towards cultural pluralism in a number of countries; national benefits to be derived from bilingualism; the needs of American ethnic groups, new immigrants, and foreign students; and the pros and…

Mayo, Donald S., Ed.

1982-01-01

141

Theme: Focus on Teaching.  

ERIC Educational Resources Information Center

|The theme focuses on the importance of teaching in vocational agriculture. Includes 10 articles on effective teaching, essential elements of the problem solving approach in teaching vocational agriculture, establishing a classroom climate for success, the economics of agriculture, dealing with student behavior problems, the importance of…

Cox, David E.; And Others

1989-01-01

142

Focus on Speaking.  

ERIC Educational Resources Information Center

This introductory text is designed to prepare teachers of English as a Second Language to teach speech skills. The first three chapters explore general issues in relation to spoken language and speech instruction. The first chapter examines the nature of spoken language, and why and how we learn our native language. The second focuses on…

Burns, Anne; Joyce, Helen

143

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

144

ENC Focus Review.  

ERIC Educational Resources Information Center

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

Thorson, Annette, Ed.

145

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

146

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

147

Focus on Phase Electives.  

ERIC Educational Resources Information Center

In this thematic issue, articles focus on the use of phase electives in the English classroom. Discussions include "Death in the Classroom,""Soapbox Operas in the English Classroom,""Language and History in Phase-Elective Programs,""Phase Electives and the Problem of Composition," and "Phase Electives and College Preparation.""Phase Electives Are…

Jones, Victor H., Ed.

1976-01-01

148

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

149

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

150

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

151

Youth Leadership. IDRA Focus.  

ERIC Educational Resources Information Center

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

IDRA Newsletter, 1995

1995-01-01

152

Focus on Dark Matter  

Microsoft Academic Search

This `Focus on Dark Matter' cluster of articles is the very first in a series of featured topics to appear in New Journal of Physics that will be of great interest to the physics community. The idea is to bring together contributions from leading researchers in topical fields to provide insights into the key issues for both experts and non-specialists

Klaus Pretzl

2000-01-01

153

Curriculum Mapping. Focus On  

ERIC Educational Resources Information Center

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

Molineaux, Rebecca

2008-01-01

154

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

155

Curriculum Mapping. Focus On  

ERIC Educational Resources Information Center

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

Molineaux, Rebecca

2008-01-01

156

Focused ion beam system  

DOEpatents

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

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

1999-08-31

157

Focused ion beam system  

DOEpatents

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

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

1999-01-01

158

Focus: DNA probes  

SciTech Connect

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

Not Available

1986-11-01

159

Generator powered plasma focus  

SciTech Connect

An earlier set of experiments will be described briefly, in which plate flux compression generators were used to power a Plasma Focus. Currents, voltages and 'rundown times' obtained in these experiments are shown to agree well with a simple model. This same model is then used to show how dramatic operational improvements could be obtained with use of an appropriate fuse, provided the model remained valid.

Fowler, C. M.

2002-01-01

160

Adaptive Focused Crawling  

Microsoft Academic Search

The large amount of available information on the Web makes it hard for users to locate resources about particular topics of\\u000a interest. Traditional search tools, e.g., search engines, do not always successfully cope with this problem, that is, helping\\u000a users to seek the right information. In the personalized search domain, focused crawlers are receiving increasing attention,\\u000a as a well-founded alternative

Alessandro Micarelli; Fabio Gasparetti

2007-01-01

161

Focused Attention in Toddlers  

PubMed Central

This longitudinal study examined individual differences and correlates of focused attention when toddlers were approximately 18 months old (T1; n = 256) and a year later (T2; n = 230). Toddlers’ attention and negative emotionality were reported by mothers and non-parental caregivers and rated globally by observers. Toddlers’ focused attention also was observed during two mother-child interactions and an independent play task. Measures of maternal emotional support and control were obtained via self-report and observation. Some contemporaneous relations among indices of toddlers’ attention were obtained, particularly for observed measures. Moreover, all measures of attention demonstrated stability across time. Negative emotionality was negatively related to toddlers’ observed attention at both ages, whereas maternal praise had positive concurrent associations. Maternal control was negatively related to observed observed attention at T2 and also predicted longitudinally, but only for children who initially had low or moderate attention. The findings suggest that individual differences in focused attention evidence stability early in life but can be influenced by adult socialization.

Gaertner, Bridget M.; Spinrad, Tracy L.; Eisenberg, Nancy

2008-01-01

162

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

163

The mechanism of interaction between focused ultrasound and microbubbles in blood-brain barrier opening in mice  

PubMed Central

The activation of bubbles by an acoustic field has been shown to temporarily open the blood-brain barrier (BBB), but the trigger cause responsible for the physiological effects involved in the process of BBB opening remains unknown. Here, the trigger cause (i.e., physical mechanism) of the focused ultrasound-induced BBB opening with monodispersed microbubbles is identified. Sixty-seven mice were injected intravenously with bubbles of 1–2, 4–5, or 6–8??m in diameter and the concentration of 107 numbers/ml. The right hippocampus of each mouse was then sonicated using focused ultrasound (1.5?MHz frequency, 100 cycles pulse length, 10?Hz pulse repetition frequency, 1?min duration). Peak-rarefactional pressures of 0.15, 0.30, 0.45, or 0.60?MPa were applied to identify the threshold of BBB opening and inertial cavitation (IC). Our results suggest that the BBB opens with nonlinear bubble oscillation when the bubble diameter is similar to the capillary diameter and with inertial cavitation when it is not. The bubble may thus have to be in contact with the capillary wall to induce BBB opening without IC. BBB opening was shown capable of being induced safely with nonlinear bubble oscillation at the pressure threshold and its volume was highly dependent on both the acoustic pressure and bubble diameter.

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

2011-01-01

164

Focus Issue: Plant Communication  

NSDL National Science Digital Library

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

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

2006-02-14

165

Dielectrophoretic columnar focusing device  

DOEpatents

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

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

2010-05-11

166

Regadenoson: a focused update.  

PubMed

Since its approval by the Food and Drug Administration in 2008, regadenoson has become the most commonly used vasodilator in the United States. Previous reviews have summarized the pre-clinical and clinical data on the use of regadenoson for myocardial perfusion imaging (MPI). Since then, data have emerged on the safety of this agent in special groups of patients such as those with chronic kidney disease, airway disease (asthma and chronic obstructive pulmonary disease), and liver disease. There has also been recent interest in the use of regadenoson in hybrid protocols with exercise as a way to improve patient tolerance and image quality. Finally, although regadenoson was approved for clinical use based on the agreement rate of regadenoson MPI and adenosine MPI with regards to perfusion abnormalities, data are now available on the prognostic data derived from regadenoson MPI. We will briefly summarize these recent reports here in a focused update on the use of regadenoson for MPI. PMID:23229649

Ghimire, Gopal; Hage, Fadi G; Heo, Jaekyeong; Iskandrian, Ami E

2013-04-01

167

Focus Issue: Measurement on a Small Scale  

NSDL National Science Digital Library

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

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

2006-03-21

168

Focusing on Focus Group Use in Educational Research.  

ERIC Educational Resources Information Center

|This paper gives a brief overview of the focus group method, its history, and usefulness for educational researchers and outlines the essential steps to a successful focus group. An example of the use of focus groups is given. The focus group originated in the 1920s in the social sciences, developed further in market research, and is undergoing a…

Jarrell, Michele G.

169

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).

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

170

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

171

Focusing on flu  

PubMed Central

School-located immunization programs (SLIP) will only be successful if parents consent to their children's participation. It is critical to understand parent perspectives regarding the factors that make them more or less likely to provide that consent. Organizations creating SLIPs will be able to capitalize on the aspects of SLIPs that parents appreciate, and address and correct issues that may give rise to parent concerns. This study involved five focus groups among the parents of school students in a large, urban school district. Findings highlight the broad range of concepts important to parents when considering participation in a SLIP. The safety and trust issues regarding vaccines in general that are so important to parents are also important to parents when considering participation in a SLIP. Effective communication strategies that include assurances regarding tracking of information and the competence and experience of immunizers will be helpful when addressing parents regarding SLIPs. In addition, parents were very cognizant of and positive regarding the public health benefits associated with SLIPs. Further study among larger populations of parents will further refine these ideas and aid in the development of successful influenza vaccine SLIPs that directly address and communicate with parents about the issues most important to them.

Middleman, Amy B.; Short, Mary B.; Doak, Jean S.

2012-01-01

172

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

173

Corporate focus and stock returns  

Microsoft Academic Search

Greater corporate focus is consistent with shareholder wealth maximization. Diseconomies of scope in the 1980s are confirmed by a trend towards focus or specialization, a positive relation between stock returns and focus increases, and the failure of diversified firms to exploit financial economies of scope (coinsurance of debt or reliance on internal capital markets). Large focused firms were less likely

Gregg A. Jarrell

1995-01-01

174

EDITORIAL: Focus on Graphene  

NASA Astrophysics Data System (ADS)

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

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

2009-09-01

175

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

176

Recent developments in capillary isoelectric focusing.  

PubMed

The developments in capillary isoelectric focusing (cIEF) over the period 2003-2007 are reviewed. With the focus on technological aspects, cIEF papers published in the fields of methodology, new techniques, detection, multidimensional systems, miniaturization and applications are summarized. The methodology section covers recent research in ampholytes composition, detergents and other additives, carrier ampholyte free cIEF, coatings and other capillary modifications. In the section on new systems adjustments to the technique (e.g. dynamic IEF), different applications of cIEF (e.g. as injection system) and new devices are reported. Systems focusing on whole column imaging, fluorescence and chemiluminescence detection and coupling to mass spectrometers are discussed in the section on detection. Interfacing cIEF with MS via RPLC systems and hyphenation of cIEF with capillary electrochromatography and other capillary electrophoresis modes are also summarized. Papers focusing on miniaturization are reviewed in the section on microfluidic devices. The section on applications will show analysis of biopharmaceutical compounds and isolated proteins for metabolomic studies. For the analysis of complex biological matrices, generally multidimensional systems are needed, which are mentioned throughout this review. PMID:18565533

Silvertand, L H H; Toraño, J Sastre; van Bennekom, W P; de Jong, G J

2008-05-27

177

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

178

Focus control system for laser welding.  

PubMed

We describe a focus control system for Nd:YAG laser welding based on an optical sensor incorporated into the fiber delivery system to detect light generated by the process. This broadband light is separated into two wavelength bands, and simple electronic processing gives a signal proportional to focal error as a result of chromatic aberrations in the optical delivery system. Focus control is demonstrated for bead-on-plate welds in different thicknesses of titanium alloy, aluminum alloy, mild steel, and stainless steel. The control system works for both pulsed and continuous laser radiation. PMID:18259340

Haran, F M; Hand, D P; Peters, C; Jones, J D

1997-07-20

179

Study of focusing aid techniques.  

National Technical Information Service (NTIS)

The study of focusing aid techniques was conducted to evaluate the performance and convenience of the split image, projection, and ground glass techniques used for focusing oscilloscope cameras. Specifically, the study was intended (1) to determine the us...

J. C. Champeny P. H. Zavattaro

1966-01-01

180

Microflow Cytometers with Integrated Hydrodynamic Focusing  

PubMed Central

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.

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

2013-01-01

181

Focusing Electron Beams at SLAC.  

ERIC Educational Resources Information Center

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

Taylor, Richard L.

1993-01-01

182

Electromagnetic focusing in biological tissues  

Microsoft Academic Search

In this work we assess the feasibility of focused electromagnetic ablation of breast cancer. In our approach we consider two degrees of freedom, namely the bolus permittivity and the operational frequency. The electric fi elds in at wo- dimensional configuration are computed per source using the iterative conjugate gradient method. The fields are subsequently focused in two lesions. The focusing

W. M. Brink; I. E. Lager; B. J. Kooij

2011-01-01

183

Mirror alignment and focus of point-focus solar concentrators  

Microsoft Academic Search

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

Richard B. Diver

1994-01-01

184

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

PubMed

Tissue-mimicking materials (TMMs) can provide a convenient, stable, and reproducible means for testing high intensity focused ultrasound (HIFU) devices. When TMMs containing thermal sensors are used to measure ultrasound-induced temperature rise, it is important that measurement results reasonably represent those that occur in biological tissue. Therefore the aim of this paper is to compare the thermal behavior of the TMM under HIFU exposure to that of ex vivo tissue. This was accomplished using both a previously developed TMM and fresh ex vivo swine muscle that were instrumented with bare 50 µm thin wire thermocouples. HIFU at 825 kHz was focused at the thermocouple junction. 30 s exposures of increasing peak negative pressure (1 to 5 MPa) were applied and the temperature profile during and after sonication was recorded. B-mode imaging was used to monitor bubble activity during sonication. If bubble formation was noted during the sonication, the sonication was repeated at the same pressure levels two more times at 20 min intervals. Temperature traces obtained at various pressure levels demonstrated similar types of heating profiles in both the tissue and TMM, the exact nature of which depended on whether bubbles formed during the HIFU exposure. The onset of bubble activity occurred at lower ultrasonic pressures in the TMM, but the basic temperature rise features due to HIFU exposure were essentially the same for both materials. PMID:22127191

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

2011-11-29

185

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

186

NICMOS Intermediate Focus/Alignment  

NASA Astrophysics Data System (ADS)

# The purpose of this activity is to perform a series of iterative adjustments of the NICMOS pupil alignment mechanism to establish the initial optical alignment in focus and tilt for all three cameras. This proposal has been broken down into 4 sub-proposals to make implementation easier. The four phases of the NICMOS Focus/Alignment activity are: # 1} Pre-Alignment Check-out {prop 7134} 2} Coarse Optical Alignment {Initial Focus Sweep} {prop 7041} 3} Intermediate Focus/Alignment {prop 7135} 4} Fine Optical Alignment {prop 7042} # This is proposal 7135; Intermediate Focus/Alignment -------------------------- Objectives: a} Estimate PAM focus and X/Y tilt for each camera b} Check performance over camera fields of view c} Allow sufficient time for dewar temperatures to equilibrate before next activity

Schneider, Glenn

1997-12-01

187

Focus  

Microsoft Academic Search

\\u000a In our understanding, a project is defined to be a job in its most general meaning with certain characteristics:\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a It is unique. The job has to be done once. An identical project has never been done before. That means, it is no routine job.\\u000a It may well be that similar jobs have been performed before.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a It is complex.

Alf Kimms

188

Mirror alignment and focus of point-focus solar concentrators  

SciTech Connect

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

Diver, R.B.

1994-11-01

189

Mirror alignment and focus of point-focus solar concentrators  

NASA Astrophysics Data System (ADS)

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

Diver, Richard B.

190

Focus Groups Help To Focus the Marketing Strategy.  

ERIC Educational Resources Information Center

|A university-based degree completion program for adults conducted focus group research to refine market positioning and promotion. Focus groups averaged five current students and recent graduates who reflected, demographically, the current student population. Results gave insight into reasons for selecting the university, aspects of the program…

Ashar, Hanna; Lane, Maureen

1996-01-01

191

Focus Groups Help To Focus the Marketing Strategy.  

ERIC Educational Resources Information Center

A university-based degree completion program for adults conducted focus group research to refine market positioning and promotion. Focus groups averaged five current students and recent graduates who reflected, demographically, the current student population. Results gave insight into reasons for selecting the university, aspects of the program…

Ashar, Hanna; Lane, Maureen

1996-01-01

192

Pediatric Focused Safety Review: Intuniv  

Center for Biologics Evaluation and Research (CBER)

Text Version... Pediatric Focused Safety Review: INTUNIV® (guanfacine hydrochloride XR) ... Background Drug Information (continued) INTUNIV® (guanfacine XR) ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

193

Depths from Focusing and Defocusing.  

National Technical Information Service (NTIS)

This paper studies the problem of obtaining depth information from focusing and defocusing, which have long been noticed as important sources of depth information for human and machine vision. In depth from focusing, we try to eliminate the local maxima p...

N. Muscettola

1993-01-01

194

Mirror alignment and focus of point-focus solar concentrators.  

National Technical Information Service (NTIS)

Distributed point-focusing solar concentrators are being developed for dish-Stirling systems and other applications. Many of these concentrators make use of faceted mirrors that have to be accurately aligned. Some of the solar concentrator designs use str...

R. B. Diver

1994-01-01

195

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

196

Focusing device for concentrating radiation  

SciTech Connect

A focusing device for concentrating radiation, such as sunlight, and producing a prescribed distribution of energy over a target surface is disclosed. The principles of the device have both photovoltaic and photothermal applications, and can be embodied in either a lens or a mirror, having a plurality of discrete focusing surfaces for redirecting radiation onto a target surface. The angle for each of the respective focusing surfaces, relative to the direction of the radiation being received, is selected to redirect an increment of such radiation to a unique portion of the target surface, whereby a superposition of the radiation increments redirected by all of the focusing surfaces produces the prescribed distribution of energy on the target. In one embodiment, a plurality of focusing segments is provided each having a plurality of the focusing surfaces for irradiating the target surface with a prescribed energy distribution. Apparatus is provided for selectively masking predetermined ones of the focusing segments for controllably adjusting the magnitude of light energy concentrated upon the target surface in a plurality of known and discrete steps.

Holdridge, D.W.

1982-01-26

197

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

198

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

199

Pediatric Focused Safety Review: Valganciclovir ...  

Center for Biologics Evaluation and Research (CBER)

Text VersionPage 1. 1 Pediatric Focused Safety Review: Valganciclovir Hydrochloride (Valcyte) Pediatric Advisory Committee Meeting May 2011 ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

200

Plutonium focus area: Technology summary.  

National Technical Information Service (NTIS)

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 wo...

1996-01-01

201

Isoelectric Focusing in a Drop  

PubMed Central

A novel approach to molecular separations is investigated using a technique termed droplet-based isoelectric focusing. Drops are manipulated discretely on a superhydrophobic surface, subjected to low voltages for isoelectric focusing, and split—resulting in a preparative separation. A universal indicator dye demonstrates the generation of stable, reversible pH gradients (3–10) in ampholyte buffers and these gradients lead to protein focusing within the drop length. Focusing was visually characterized, spectroscopically verified, and assessed quantitatively by non-invasive light scattering measurements. It was found to correlate with a quantitative model based on 1D steady state theory. This work illustrates that molecular separations can be deployed within a single open drop and the differential fractions can be separated into new discrete liquid elements.

Weiss, Noah G.; Hayes, Mark A.; Garcia, Antonio A.; Ansari, Rafat R.

2010-01-01

202

Developing a Focused Research Effort.  

ERIC Educational Resources Information Center

The author discusses a method to produce a cluster of focused nursing research projects. Her method includes (1) focal topic identification, (2) development, (3) communication, (4) integration, (5) collaboration, and (6) balance. (CH)

Lenz, Elizabeth R.

1987-01-01

203

Focusing on Contact Lens Safety  

MedlinePLUS

... regulates contact lenses—including those intended for vision correction and for decorative purposes—as prescription devices, and ... ability to focus. It's primarily used for the correction of nearsightedness. The most common type is overnight ...

204

NICMOS Focus Field Variations (FFV) and Focus Centering±  

NASA Astrophysics Data System (ADS)

NICMOS foci are known to vary across detector’s field of view. These variations must be taken into account when determining "best" focus from a particular stellar image. Focus field variations (FFV) may introduce substantial positional dependence in aperture corrections, thus they may also be important for high precision stellar photometry. In this report, we present empirical results of a study of time dependence as well as PAM setting dependence of FFV for the NICMOS cameras. Although the results are not easy to interprete because of substantial errors, they still suggest that some amount of both time and PAM position dependence of FFV is consistent with the cameras 2 and 3 data. There is a preliminary understanding of why FFV should depend on PAM setting and may change with time. However a detailed interpretation of the actual FFV time and PAM dependence is beyond the scope of this report and is left for future analysis. As a practical result, we present the coefficients of the second order surface fit to the FFV data averaged over time and PAM positions. They are recommended for use in the NICMOS focus monitoring program to reduce focus to the detector center (focus "centering").

Suchkov, A.; Galas, G.

1998-03-01

205

NICMOS Focus Field Variations (FFV) and Focus Centering  

NASA Astrophysics Data System (ADS)

NICMOS foci are known to vary across detector's field of view. These variations must be taken into account when determining ``best'' focus from a particular stellar image. Focus field variations (FFV) may introduce substantial positional dependence in aperture cor- rections, thus they may also be important for high precision stellar photometry. In this report, we present empirical results of a study of time dependence as well as PAM setting dependence of FFV for the NICMOS cameras. Although the results are not easy to inter- prete because of substantial errors, they still suggest that some amount of both time and PAM position dependence of FFV is consistent with the cameras 2 and 3 data. There is a preliminary understanding of why FFV should depend on PAM setting and may change with time. However a detailed interpretation of the actual FFV time and PAM dependence is beyond the scope of this report and is left for future analysis. As a practical result, we present the coefficients of the second order surface fit to the FFV data averaged over time and PAM positions. They are recommended for use in the NICMOS focus monitoring pro- gram to reduce focus to the detector center (focus "centering").

Galas, G.; Suchkov, A.

1998-09-01

206

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

207

Focusing and leveling in dual stage lithographic system  

NASA Astrophysics Data System (ADS)

As a key technology in lithographic system, the wafer stage is a six-degree of freedom and long stroke movement platform whose movement and positioning accuracy are up to nano-scale, and it involves precision machinery, precision measurement, automation and materials science in one complex system. In the lithography process, the function of the stage includes: wafer transmission, alignment, focusing and leveling, scanning exposure and so on. Positioning accuracy of the stage directly affects the alignment accuracy, as well as focusing accuracy, thus affecting the improvement of lithographic resolution as a whole. For the rapid increasing in chip integration, the chip makers acquire higher throughput of the lithographic system, under the demand, there has been dual-stage technology, i.e., in one lithographic system, there are two wafer stages, which separately locates at measurement position and exposure location. They run independently and in parallel, when the measurement and the exposure are completed, the two stages exchange their positions and functions. The dual stage technology not only significantly increases the yield, but also improves the measurement accuracy in focus detection. Focusing and leveling in dual stage is different from that in single stage. In this paper, combination of grating-based focus detection and dual stage technology is used to introduce leveling and focusing in dual-stage system. The principle of focus detection, the way for height information transforming to the wafer leveling data, as well as the servo of focusing and leveling at exposure location are carried out in detail.

Li, Jinlong; Zhao, Lixin; Hu, Song; Zhou, Shaolin

2010-05-01

208

Direct model for thin wetting film focusing  

NASA Astrophysics Data System (ADS)

We demonstrated that the use of thin wetting film focusing allows detection of single micrometer-size objects with 24 mm2 lensfree imaging. In order to refine the technique and push the detection limit down to the nanometer scale, a deep insight in the imaging mechanisms is necessary. We constructed a model based on wetting film microfluidics and Fresnel diffraction of light. This model properly fits the intensity measurements acquired on micro-particles with our lensfree imaging setup. When the particle diameter is 1 µm, a microlens is formed by a liquid surface deformation of about 100 nm in height over few microns radial distance. The measured point spread function of the light deflected by such microlens presents a constant beam intensity over a long range, between 50 µm and 250 µm from the object plane. This is very similar to what is obtained by illuminating an axicon with a Gaussian beam, i.e. the central beam propagates for several Rayleigh ranges without appreciable divergences. In the lensfree imaging setup, the detector plane is far apart from the object (?500 µm). Thus, it is a true advantage to form axicon lens that can propagate strong intensity beams up to the detector plane. Most important, our model predicts that the detection of smaller objetcs needs thinner films. These results are important for further detecting viruses with lensfree imaging techniques.

Migliozzi, D.; Allier, C. P.; Hennequin, Y.; Coutard, J.-C.; Dinten, J.-M.

2013-02-01

209

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

210

New charm results from FOCUS  

SciTech Connect

New results from the photoproduction experiment FOCUS are reported: Dalitz plot analysis, semileptonic form factor ratios and excited meson spectroscopy. The author reports on three new results from the photoproduction experiment FOCUS: the first Dalitz plot analysis of charm meson decays using the K-matrix approach[ 1], new measurements of the D{sub s}{sup +} {yields} {delta}(1020) {mu}{sup +}{nu} form factor ratios [2], and new measurements on L=1 excited meson spectroscopy [3], i.e., precise measurements of the masses and widths of the D*{sub 2}{sup +} and D*{sub 2}{sup 0} mesons, and evidence for broad states decaying to D{sup +}{pi}{sup -}, D{sup 0}{pi}{sup +} (the first such evidence in D{sup 0}{pi}{sup +}). The data for this paper were collected in the Wideband photoproduction experiment FOCUS during the Fermilab 1996-1997 fixed-target run.

Bianco, Stefano; /Frascati

2004-12-01

211

Focused OCT and LIF endoscope  

NASA Astrophysics Data System (ADS)

A new focused OCT-LIF endoscope has been constructed for high resolution imaging between 325 nm and 1300 nm. This endoscope is 2 mm in diameter for non-destructive imaging in vivo. A reflective design ball lens is employed that eliminates the difficulty of operating achromatically over a large range, while taking advantage of TIR at two faces and coating a third mirror face internally to focus the beams downwards. It is a 1:1 imaging system that obtains a theoretical diffraction-limited resolution for both the OCT (800-1300 nm) and LIF (greater than 325 nm) channels.

Wall, R. Andrew; Bonnema, Garret T.; Barton, Jennifer K.

2010-02-01

212

Speeding chemical reactions by focusing  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

213

Finding beam focus errors automatically  

SciTech Connect

An automated method for finding beam focus errors using an optimization program called COMFORT-PLUS. The steps involved in finding the correction factors using COMFORT-PLUS has been used to find the beam focus errors for two damping rings at the SLAC Linear Collider. The program is to be used as an off-line program to analyze actual measured data for any SLC system. A limitation on the application of this procedure is found to be that it depends on the magnitude of the machine errors. Another is that the program is not totally automated since the user must decide a priori where to look for errors. (LEW)

Lee, M.J.; Clearwater, S.H.; Kleban, S.D.

1987-01-01

214

NICMOS Optimum Coronagraphic Focus Determinaton  

NASA Astrophysics Data System (ADS)

As originally designed the NICMOS coronagraph had two focii at conjugate points in the optical path with the coronagraphic hole at the f/24 focus of the input OTA beam, and the detector at the reimaged f/45 focus in Camera 2. Because of the forward displacement of the cold optical bench holding the Camera 2 detector, as a result of the larger-than-expected expansion of the solid N2 cryogen {as described and documented by the 'Dewar Anomoly Review Board'}, the two focii are now aconjugate. For direct imaging this is of little concern, and the HST/NICMOS Camera 2 focus interface is established by co-locating the f/45 image plane on the detector. This is done by de-spacing the relayed focus through a translative motion {with compensating comal tilt correction} of the Pupil Alignment Mechanism {PAM}. The mirror which this mechanism drives is upstream of the field divider mirror upon which the coronagraphic hole resides. Therefore, achieving a "best" focus at the detector results in a "soft" focus {in the f/24 image plane} at the coronagraphic hole. This leads to a wavelength-dependent increase in the diffracted energy in the now-defocused unocculted wings of a PSF from a target placed inside of the coronagraphic hole {as the f/24 image plane will fall behind the surface of the camera 2 field divider mirror} increasing the scattered and diffracted background around the target and lowering the field contrast at the detector image plane. In principal the coronagraphic stray light rejection would be most efficient by minimizing the spot size of an input PSF in the hole. This, however, is traded against a small degree of defocus at the detector. Ultimately, the best coronagraphic performance is achieved where the image contrast between an unocculted target and the residual background from an occulted source {both affected differently by focus and subsequent scattering} is maximized. The purpose of this test is to find the optimum PAM position to maximize the coronagraphic image:background contrast ratio. Further details and background information may be found in the SMOV/7157 test report "NICMOS Optimal Coronagraphic Focus Determination" available from the NICMOS IDT.

Schneider, Glenn

2001-07-01

215

Capillary Isoelectric Focusing of Individual Mitochondria  

PubMed Central

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

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

2011-01-01

216

EUV Focus Sensor: Design and Modeling  

SciTech Connect

We describe performance modeling and design optimization of a prototype EUV focus sensor (FS) designed for use with existing 0.3-NA EUV projection-lithography tools. At 0.3-NA and 13.5-nm wavelength, the depth of focus shrinks to 150 nm increasing the importance of high-sensitivity focal-plane detection tools. The FS is a free-standing Ni grating structure that works in concert with a simple mask pattern of regular lines and spaces at constant pitch. The FS pitch matches that of the image-plane aerial-image intensity: it transmits the light with high efficiency when the grating is aligned with the aerial image laterally and longitudinally. Using a single-element photodetector, to detect the transmitted flux, the FS is scanned laterally and longitudinally so the plane of peak aerial-image contrast can be found. The design under consideration has a fixed image-plane pitch of 80-nm, with aperture widths of 12-40-nm (1-3 wavelengths), and aspect ratios of 2-8. TEMPEST-3D is used to model the light transmission. Careful attention is paid to the annular, partially coherent, unpolarized illumination and to the annular pupil of the Micro-Exposure Tool (MET) optics for which the FS is designed. The system design balances the opposing needs of high sensitivity and high throughput optimizing the signal-to-noise ratio in the measured intensity contrast.

Goldberg, Kenneth A.; Teyssier, Maureen E.; Liddle, J. Alexander

2005-05-01

217

Electrically tunable transverse magnetic focusing in graphene  

NASA Astrophysics Data System (ADS)

Electrons in a periodic lattice can propagate without scattering for macroscopic distances despite the presence of the non-uniform Coulomb potential due to the nuclei. Such ballistic motion of electrons allows the use of a transverse magnetic field to focus electrons. This phenomenon, known as transverse magnetic focusing (TMF), has been used to study the Fermi surface of metals and semiconductor heterostructures, as well as to investigate Andreev reflection and spin-orbit interaction, and to detect composite fermions. Here we report on the experimental observation of TMF in high-mobility mono-, bi- and tri-layer graphene devices. The ability to tune the graphene carrier density enables us to investigate TMF continuously from the hole to the electron regime and analyse the resulting focusing fan. Moreover, by applying a transverse electric field to tri-layer graphene, we use TMF as a ballistic electron spectroscopy method to investigate controlled changes in the electronic structure of a material. Finally, we demonstrate that TMF survives in graphene up to 300 K, by far the highest temperature reported for any system, opening the door to new room-temperature applications based on electron-optics.

Taychatanapat, Thiti; Watanabe, Kenji; Taniguchi, Takashi; Jarillo-Herrero, Pablo

2013-04-01

218

Focused OCT and LIF endoscope  

Microsoft Academic Search

A new focused OCT-LIF endoscope has been constructed for high resolution imaging between 325 nm and 1300 nm. This endoscope is 2 mm in diameter for non-destructive imaging in vivo. A reflective design ball lens is employed that eliminates the difficulty of operating achromatically over a large range, while taking advantage of TIR at two faces and coating a third

R. Andrew Wall; Garret T. Bonnema; Jennifer K. Barton

2010-01-01

219

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

220

NASA Budget Focuses on Exploration  

Microsoft Academic Search

NASA has decided to rebalance its priorities following several years of healthy growth for science, turning its focus instead towards expanding support for manned space exploration, explained NASA Administrator Michael Griffin at a 16 February hearing before the U.S. House of Representatives Committee on Science. The Bush Administration has requested $16.8 billion for NASA in Fiscal Year 2007, an increase

Sarah Zielinski

2006-01-01

221

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

222

NICMOS Focus Monitoring Cycle 16  

NASA Astrophysics Data System (ADS)

This program is a version of the standard focus sweep used since cycle 7. It has been modified to go deeper and uses more narrow filters for improved focus determination. A new source was added in Cycle 14 in order to accomodate 2-gyro mode: the open cluster NGC1850. This source is part of the current proposal. The old target, the open cluster NGC3603, will be used whenever available and the new target used to fill the periods when NGC3603 is not visible. Steps: a Use refined target field positions as determined from cycle 7 calibrations b Use MULTIACCUM sequences of sufficient dynamic range to account for defocus c Do a 17-point focus sweep, +/- 8mm about the PAM mechanical zeropoint for each cameras 1 and 2, in 1.0mm steps. For NIC3 we step from -0.5mm to -9.5mm relative to mechanical zero, in steps of 1.0mm. d Use PAM X/Y tilt and OTA offset slew compensations refined from previous focus monitoring/optical alignment activities;

Wiklind, Tommy

2007-07-01

223

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

224

Wolter optics for neutron focusing  

Microsoft Academic Search

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.

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

2011-01-01

225

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

226

Non-Imaging, Focusing Heliostat  

Microsoft Academic Search

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

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

2001-01-01

227

Student Focused Math Content Coaching  

NSDL National Science Digital Library

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

Foster, David

2012-02-01

228

Evaluating Pragmatics-Focused Materials  

ERIC Educational Resources Information Center

Learners often find the area of pragmatics (that is, using speech acts such as requesting, inviting, and complimenting) problematic. Teachers are urged to teach pragmatic aspects of language, and make use of authentic samples of spoken discourse to do so. However, information about the effectiveness of pragmatics-focused instruction of this nature…

Crandall, Elizabeth; Basturkmen, Helen

2004-01-01

229

Assigning geographical focus to documents  

Microsoft Academic Search

Geographical information becomes a kind of very important attribute for web documents, considering the fact that a large proportion of documents on the web contain geographical information. GIR (Geographical information retrieval) systems can identify those geographical information and extract the geographical focus in the documents automatically, hence supporting geo-related queries for information retrieval. Therefore, GIR has become a hot topic

Min Chen; Xing Lin; Yi Zhang; Xingguang Wang; Hao Yu

2010-01-01

230

Some facts about “weapon focus  

Microsoft Academic Search

“Weapon focus” refers to the concentration of acrime witness's attention on a weapon, and the resultant reduction in ability to remember other details of the crime. We examined this phenomenon by presenting subject-witnesses with a series of slides depicting an event in a fast-food restaurant. Half of the subjects saw a customer point a gun at the cashier; the other

Elizabeth F. Loftus; Geoffrey R. Loftus; Jane Messot

1987-01-01

231

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

232

Staying in School. IDRA Focus.  

ERIC Educational Resources Information Center

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

IDRA Newsletter, 1996

1996-01-01

233

Spatio-temporal analysis of molecular delivery through the blood brain barrier using focused ultrasound  

Microsoft Academic Search

The deposition of gadolinium through ultrasound-induced blood-brain barrier (BBB) openings in the murine hippocampus was investigated. First, wave propagation simulations through the intact mouse skull revealed minimal beam distortion while thermal deposition simulations, at the same sonication parameters used to induce BBB opening in vivo, revealed temperature increases lower than 0.5 °C. The simulation results were validated experimentally in ex

J. J. Choi; M. Pernot; T. R. Brown; S. A. Small; E. E. Konofagou

2007-01-01

234

Ultrasound-induced acoustophoretic motion of microparticles in three dimensions.  

PubMed

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. PMID:24032923

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

2013-08-08

235

EDITORIAL: Focus on Gravitational Lensing  

NASA Astrophysics Data System (ADS)

Gravitational lensing emerged as an observational field following the 1979 discovery of a doubly imaged quasar lensed by a foreground galaxy. In the 1980s and '90s dozens of other multiply imaged systems were observed, as well as time delay measurements, weak and strong lensing by galaxies and galaxy clusters, and the discovery of microlensing in our galaxy. The rapid pace of advances has continued into the new century. Lensing is currently one of best techniques for finding and mapping dark matter over a wide range of scales, and also addresses broader cosmological questions such as understanding the nature of dark energy. This focus issue of New Journal of Physics presents a snapshot of current research in some of the exciting areas of lensing. It provides an occasion to look back at the advances of the last decade and ahead to the potential of the coming years. Just about a decade ago, microlensing was discovered through the magnification of stars in our galaxy by invisible objects with masses between that of Jupiter and a tenth the mass of the Sun. Thus a new component of the mass of our galaxy, dubbed MACHOs, was established (though a diffuse, cold dark matter-like component is still needed to make up most of the galaxy mass). More recently, microlensing led to another exciting discovery—of extra-solar planets with masses ranging from about five times that of Earth to that of Neptune. We can expect many more planets to be discovered through ongoing surveys. Microlensing is the best technique for finding Earth mass planets, though it is not as productive overall as other methods and does not allow for follow up observations. Beyond planet hunting, microlensing has enabled us to observe previously inaccessible systems, ranging from the surfaces of other stars to the accretion disks around the black holes powering distant quasars. Galaxies and galaxy clusters at cosmological distances can produce dramatic lensing effects: multiple images of background galaxies or quasars which are strongly magnified and sheared. In the last decade, double and quadruply imaged systems due to galactic lenses have been studied with optical and radio observations. An interesting result obtained from the flux ratio 'anomalies' of quadruply imaged systems is the statistical detection of dark sub-clumps in galaxy halos. More broadly, while we have learned a lot about the mass distribution in lens galaxies and improved time delay constraints on the Hubble constant, the limitations of cosmological studies with strong lensing due to uncertainties in lens mass models have also come to be appreciated. That said, progress will no doubt continue with qualitative advances in observations such as astrometric counterparts to the flux anomalies, clever ideas such as the use of spectroscopic signatures to assemble the SLACS lens sample, and combining optical imaging, spectroscopy and radio data to continue the quest for a set of golden lenses to measure the Hubble constant. Galaxy clusters are a fascinating arena for studying the distribution of dark and baryonic matter. Weak and strong lensing information can be combined with dynamical information from the spectroscopic measurements of member galaxies and x-ray/Sunyaev Zeldovich measurements of the hot ionized gas. Hubble Space Telescope observations have yielded spectacular images of clusters, such as Abell 1689, which has over a hundred multiply imaged arcs. Mass measurements have progressed to the level of 10 percent accuracy for several clusters. Unfortunately, it is unclear if one can do much better for individual clusters given inherent limitations such as unknown projection effects. The statistical study of clusters is likely to remain a promising way to study dark matter, gravity theories, and cosmology. Techniques to combine weak and strong lensing information to obtain the mass distribution of clusters have also advanced, and work continues on parameter-free techniques that are agnostic to the relation of cluster light and mass. An interesting twist in cluster lensing was provided by the pos

Jain, Bhuvnesh

2007-11-01

236

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

237

Heating in vascular tissue and flow-through tissue phantoms induced by focused ultrasound  

NASA Astrophysics Data System (ADS)

High intensity focused ultrasound (HIFU) can be used to control bleeding, both from individual blood vessels as well as from gross damage to the capillary bed. This process, called acoustic hemostasis, is being studied in the hope that such a method would ultimately provide a lifesaving treatment during the so-called "golden hour", a brief grace period after a severe trauma in which prompt therapy can save the life of an injured person. Thermal effects play a major role in occlusion of small vessels and also appear to contribute to the sealing of punctures in major blood vessels. However, aggressive ultrasound-induced tissue heating can also impact healthy tissue and can lead to deleterious mechanical bioeffects. Moreover, the presence of vascularity can limit one's ability to elevate the temperature of blood vessel walls owing to convective heat transport. In an effort to better understand the heating process in tissues with vascular structure we have developed a numerical simulation that couples models for ultrasound propagation, acoustic streaming, ultrasound heating and blood cooling in Newtonian viscous media. The 3-D simulation allows for the study of complicated biological structures and insonation geometries. We have also undertaken a series of in vitro experiments, in non-uniform flow-through tissue phantoms, designed to provide a ground truth verification of the model predictions. The calculated and measured results were compared over a range of values for insonation pressure, insonation time, and flow rate; we show good agreement between predictions and measurements. We then conducted a series of simulations that address two limiting problems of interest: hemostasis in small and large vessels. We employed realistic human tissue properties and considered more complex geometries. Results show that the heating pattern in and around a blood vessel is different for different vessel sizes, flow rates and for varying beam orientations relative to the flow axis. Complete occlusion and wall-puncture sealing are both possible depending on the exposure conditions. These results concur with prior clinical observations and may prove useful for planning of a more effective procedure in HIFU treatments.

Huang, Jinlan

238

The ionospheric focused heating experiment  

Microsoft Academic Search

The Ionospheric Focused Heating rocket was launched on May 30, 1992. The sounding rocket carried an instrument and chemical payload along a trajectory that crossed the intersection of the beams from the 430-MHz incoherent scatter radar and the 5.1-MHz high-power radio wave facility near Arecibo. The release of 30 kg of CFâBr into the F region at 285 km altitude

P.A. Bernhardt; C. L. Siefring; P. Rodriguez; D. G. Haas; M. M. Baumback; H. A. Romero; D. A. Solin; F. T. Djuth; L. M. Duncan; D. E. Hunton; C. J. Pollock; M. P. Sulzer; C. A. Tepley; L. S. Wagner; J. A. Goldstein

1995-01-01

239

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

240

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

241

Focus on phosphoaspartate and phosphoglutamate  

Microsoft Academic Search

Protein phosphorylation is a common signalling mechanism in both prokaryotic and eukaryotic organisms. Whilst the focus of\\u000a protein phosphorylation research has primarily been on protein serine\\/threonine or tyrosine phosphorylation, there are other\\u000a phosphoamino acids that are also biologically important. Two of the phosphoamino acids that are functionally involved in the\\u000a biochemistry of protein phosphorylation and signalling pathways are phosphoaspartate and

P. V. Attwood; P. G. Besant; Matthew J. Piggott

2011-01-01

242

Focused electron beam in pyroelectric electron probe microanalyzer.  

PubMed

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

Imashuku, Susumu; Imanishi, Akira; Kawai, Jun

2013-07-01

243

Flow focusing with viscoelastic liquids  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

244

INT prime focus mosaic camera  

NASA Astrophysics Data System (ADS)

The INT Prime Focus Mosaic Camera (INT PFC) is designed to provide a large field survey and supernovae search capability for the prime focus of the 2.5 m Isaac Newton Telescope (INT). It is a joint collaboration between the Royal Greenwich Observatory (UK), Kapteyn Sterrenwacht Werkgroep (Netherlands), and the Lawrence Berkeley Laboratories (USA). The INT PFC consists of a 4 chip mosaic utilizing thinned and anti-reflection coated CCDs. These are LORAL devices of the LICK3 design. They will be operated cryogenically in a purpose built camera assembly. A fifth CCD, of the same type, is co-mounted with the science array in the cryostat to provide autoguider functions. This cryostat then mounts to the main camera assembly at the prime focus. This assembly will include standard filters and a novel shutter wheel which has been specifically designed for this application. The camera will have an unvignetted field of 40 arcminutes and a focal ratio of f/3.3. This results in a very tight mechanical specification for co-planarity and flatness of the array of CCDs and also quite stringent flexure tolerance of the camera assembly. A method of characterizing the co- planarity and flatness of the array will be described. The overall system architecture will also be described. One of the main requirements is to read the whole array out within 100s, with less than 10e rms. noise and very low CCD cross talk.

Ives, Derek J.; Tulloch, Simon; Churchill, John

1996-03-01

245

Vehicle detection from aerial imagery  

Microsoft Academic Search

Vehicle detection from aerial images is becoming an increasingly important research topic in surveillance, traffic monitoring and military applications. The system described in this paper focuses on vehicle detection in rural environments and its applications to oil and gas pipeline threat detection. Automatic vehicle detection by unmanned aerial vehicles (UAV) will replace current pipeline patrol services that rely on pilot

Joshua Gleason; Ara V. Nefian; Xavier Bouyssounousse; Terry Fong; George Bebis

2011-01-01

246

Laser focus accelerator by relativistic self-focusing and high electric fields in double layers of nonlinear force produced cavitons  

Microsoft Academic Search

The laser focus accelerator with relativistic self-focusing for achieving Z-separated heavy ions of energies beyond 10 GeV was studied experimentally, in detailed numerical work and estimations on intense muon sources, heavy nuclear collisions and generation of new isotopes are on the way. The recently detected inverted double layers in the nonlinear (ponderomotive) force produced cavitons with 109 V\\/cm nearly static

P. J. Clark; S. Eliezer; F. J. M. Farley; M. P. Goldsworthy; F. Green; H. Hora; J. C. Kelly; P. Lalousis; B. Luther-Davies; R. J. Stening; Wang Jin-Cheng

1985-01-01

247

Remote focusing for programmable multi-layer differential multiphoton microscopy  

PubMed Central

We present the application of remote focusing to multiphoton laser scanning microscopy and utilize this technology to demonstrate simultaneous, programmable multi-layer imaging. Remote focusing is used to independently control the axial location of multiple focal planes that can be simultaneously imaged with single element detection. This facilitates volumetric multiphoton imaging in scattering specimens and can be practically scaled to a large number of focal planes. Further, it is demonstrated that the remote focusing control can be synchronized with the lateral scan directions, enabling imaging in orthogonal scan planes.

Hoover, Erich E.; Young, Michael D.; Chandler, Eric V.; Luo, Anding; Field, Jeffrey J.; Sheetz, Kraig E.; Sylvester, Anne W.; Squier, Jeff A.

2010-01-01

248

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

249

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

250

Tanks focus area. Annual report  

SciTech Connect

The U.S. Department of Energy Office of Environmental Management is tasked with a major remediation project to treat and dispose of radioactive waste in hundreds of underground storage tanks. These tanks contain about 90,000,000 gallons of high-level and transuranic wastes. We have 68 known or assumed leaking tanks, that have allowed waste to migrate into the soil surrounding the tank. In some cases, the tank contents have reacted to form flammable gases, introducing additional safety risks. These tanks must be maintained in the safest possible condition until their eventual remediation to reduce the risk of waste migration and exposure to workers, the public, and the environment. Science and technology development for safer, more efficient, and cost-effective waste treatment methods will speed up progress toward the final remediation of these tanks. The DOE Office of Environmental Management established the Tanks Focus Area to serve as the DOE-EM`s technology development program for radioactive waste tank remediation in partnership with the Offices of Waste Management and Environmental Restoration. The Tanks Focus Area is responsible for leading, coordinating, and facilitating science and technology development to support remediation at DOE`s four major tank sites: the Hanford Site in Washington State, Idaho National Engineering and Environmental Laboratory in Idaho, Oak Ridge Reservation in Tennessee, and the Savannah River Site in South Carolina. The technical scope covers the major functions that comprise a complete tank remediation system: waste retrieval, waste pretreatment, waste immobilization, tank closure, and characterization of both the waste and tank. Safety is integrated across all the functions and is a key component of the Tanks Focus Area program.

Frey, J.

1997-12-31

251

Innovative point focus solar concentrator  

SciTech Connect

Acurex Corporation has a Cooperative Agreement with the United States Department of Energy (DOE) to design, build and test a 15-meter diameter Innovative Point Focus Solar Concentrator. This report presents the results of the Phase I prototype reflective panel optical test. The approach selected for this test was a quick, simple, and relatively inexpensive evaluation of the first outer reflective panel produced. This approach represented a tradeoff between extent of results and test costs. The test measured the focal quality of the panel, and this result was then related to the focal quality of the complete dish assembly.

Not Available

1986-02-01

252

EDITORIAL Focus on Advanced Nanomaterials Focus on Advanced Nanomaterials  

NASA Astrophysics Data System (ADS)

The Nobel Prize in Physics 2010 was awarded to Andre Geim and Konstantin Novoselov 'for groundbreaking experiments regarding the two-dimensional material graphene'. This award acknowledged the growing importance of graphene, as well as of nanomaterials and surface phenomena at the nanoscale in general. Graphene, carbon nanotubes and many other nanostructures have already demonstrated their remarkable physical properties and a wealth of quantum phenomena. However, much work has to be done to apply these properties in practical devices and technological processes. This focus issue overviews some recent advances in this direction. It includes a foreword and eight articles on nanomaterials investigation carried out at International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science. The foreword is written by Heinrich Rohrer, who received the Nobel Prize in Physics in 1986 for the design of the scanning tunneling microscope (STM)—one of the most successful tools in the characterization and manipulation of various nanomaterials, including graphene. Professor Rohrer presents his perspectives on the trends in the past, present and future developments of nanoscience and nanotechnology. Graphene and carbon nanomaterials dominate the topics of this focus issue. Rao et al review the synthesis and characterization of the surface, magnetic and electrical properties of carbon structures containing one to several graphene layers. Moriyama et al present their recent results on the fabrication of electrical quantum-dot devices in a graphene-based two-dimensional system. By applying a nanofabrication process to graphene flakes, they fabricated a device comprising two lateral quantum dots coupled in series. Wakabayashi et al review the theoretical treatment of graphene nanoribbons and present their own recent achievements in this area. Graphene is closely related to carbon nanotubes, and their applications largely rely on the possibility of controllable functionalization. Gautam et al review an elegant method of such functionalization, namely the encapsulation of inorganic elements and compounds into carbon nanotubes. Functionalization of metal surfaces is another important topic of this focus issue. Nagao et al overview the fundamental properties of plasmons in materials with various dimensionalities. In particular, they consider antenna resonances of plasmon polariton in some widely used nanometer-scale structures and atomic-scale wires, along with their applications. Komeda et al present their molecule-resolved STM analysis of bonding metal-free phthalocyanine to gold surfaces. Such organic-inorganic interfaces have a variety of potential applications to catalysis and sensors. Nagasaki describes another organic nanotechnology related topic, namely engineering of poly(ethylene glycol) tethered chain surfaces for high-performance bionanoparticles. Finally, Fabbri et al review the role of interfaces in ionic conductivity in oxide hetero-structures, aimed at improving the design of micro-ionic devices. We hope that this focus issue will provide a valuable update on some topics in current nanomaterials research.

Tanaka, Takaho; Iakoubovskii, Konstantin

2010-10-01

253

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

254

EDITORIAL: Focus on Cloud Physics FOCUS ON CLOUD PHYSICS  

NASA Astrophysics Data System (ADS)

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

Falkovich, Gregory; Malinowski, Szymon P.

2008-07-01

255

Detecting Illegal Arms Trade  

Microsoft Academic Search

Illegal arms are responsible for thousands of deaths in civil wars every year. Yet, their trade is very hard to detect. We propose a method to statistically detect illegal arms trade based on the investor knowledge embedded in financial markets. We focus on eight countries under UN arms embargo in the period 1990-2005, and analyze eighteen events during the embargo

Stefano DellaVigna; Eliana La Ferrara

2007-01-01

256

Variable-focusing microlens with microfluidic chip  

NASA Astrophysics Data System (ADS)

A new polymer microlens with variable focusing properties is designed and fabricated. The microlens consists of a thin diaphragm with 3D convex lens, chamber and microchannel, which are made of polydimethyl-siloxane (PDMS). A novel fabrication approach has been developed to cast the PDMS microlens film using a PDMS mold. The elastomeric PDMS microlens film acts as a diaphragm. The flexible PDMS microlens and diaphragm are integrated on a microfluidic chip. By varying the pressure in the microfluidic chamber, which produces a shift in the microlens' focal plane, this can change the back focal length of lens. The new fabrication method provides easy fabrication, low-cost production and precise dimension control. Measurement with an atomic force microscope reveals that the surface roughness of the lens is 18.6 nm, and real-time contact-angle measurements show the back focus length tuning range is from 3.8 mm to 10.6 mm. The variable focal length of the microlens is critical to increase the efficiency of the light detection in optical or biophotonic applications. In this paper, the fabrication processing, mechanical and optical property testing, and simulation results are presented in detail.

Chen, Jackie; Wang, Weisong; Fang, Ji; Varahramyan, Kody

2004-05-01

257

NICMOS Optimum Coronagraphic Focus Determinaton  

NASA Astrophysics Data System (ADS)

This test will ascertain the optimum position of the PAM for maximizing the local contrast ratios in coronagraphic images. Because of the forward motion of the NICMOS optical bench and dewar, the nominal operational position for the PAM is set {for each camera} to achieve diffraction limited focus at the image plane formed at the detector. As a result of the forward motion of the camera 2 detector, hard images are no longer formed coincidentally at the field divider mirror surface {where the coronagraphic hole is located} and at the detector. This will lead to an increase in the diffracted energy in the wings of a PSF from a target placed inside of the coronagraphic hole as the image plane will fall behind the surface of the FDA mirror. The contrast in a coronagraphic image might be enhanced by placing the focus to form an image at either image planes {FDA or detector} or at a place in-between. This is highly dependent on scattering and must be ascertained by direct measurement.

Schneider, Glenn

1997-12-01

258

The paradox of moral focus.  

PubMed

When we evaluate moral agents, we consider many factors, including whether the agent acted freely, or under duress or coercion. In turn, moral evaluations have been shown to influence our (non-moral) evaluations of these same factors. For example, when we judge an agent to have acted immorally, we are subsequently more likely to judge the agent to have acted freely, not under force. Here, we investigate the cognitive signatures of this effect in interpersonal situations, in which one agent ("forcer") forces another agent ("forcee") to act either immorally or morally. The structure of this relationship allowed us to ask questions about both the "forcer" and the "forcee." Paradoxically, participants judged that the "forcer" forced the "forcee" to act immorally (i.e. X forced Y), but that the "forcee" was not forced to act immorally (i.e. Y was not forced by X). This pattern obtained only for human agents who acted intentionally. Directly changing participants' focus from one agent to another (forcer versus forcee) also changed the target of moral evaluation and therefore force attributions. The full pattern of judgments may provide a window into motivated moral reasoning and focusing bias more generally; participants may have been motivated to attribute greater force to the immoral forcer and greater freedom to the immoral forcee. PMID:21315324

Young, Liane; Phillips, Jonathan

2011-02-18

259

Argument Structure and Focus Projection in Korean  

Microsoft Academic Search

It has been claimed that syntactic structures and the argument types (e.g. theme, oblique) can determine the domain of focus: focus on a particular type of internal argument may project its focus domain to a larger syntactic constituent than the focused item. It is also known that focus often has prosodic reflections through the manipulations of prosodic phrasing, prominence relation

Hee-Sun Kim; Sun-Ah Jun; Hyuck-Joon Lee; Jong-Bok Kim

2006-01-01

260

Non-focusing active warhead  

SciTech Connect

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

Hornig, Howard C. (Castro Valley, CA)

1998-01-01

261

EDITORIAL: Focus on Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

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

2003-09-01

262

NASA Budget Focuses on Exploration  

NASA Astrophysics Data System (ADS)

NASA has decided to rebalance its priorities following several years of healthy growth for science, turning its focus instead towards expanding support for manned space exploration, explained NASA Administrator Michael Griffin at a 16 February hearing before the U.S. House of Representatives Committee on Science. The Bush Administration has requested $16.8 billion for NASA in Fiscal Year 2007, an increase of 3.2 percent over the previous year. Most of the benefit would go to the exploration program, which would get a 55 percent increase in funding-for a total of $3.9 billion-primarily for the development of the new Crew Exploration Vehicle and Crew Launch Vehicle. The science budget would grow by 1.5 percent in FY2007-to $5.3 billion-and then is projected to grow by just one percent per year in 2008-2011.

Zielinski, Sarah

2006-02-01

263

Focusing ecological research for conservation.  

PubMed

Ecologists are increasingly actively involved in conservation. We identify five key topics from a broad sweep of ecology that merit research attention to meet conservation needs. We examine questions from landscape ecology, behavioral ecology, ecosystem dynamics, community ecology, and nutrient cycling related to key topics. Based on literature review and publication trend assessment, consultation with colleagues, and roundtable discussions at the 24th International Congress for Conservation Biology, focused research on the following topics could benefit conservation while advancing ecological understanding: 1. Carbon sequestration, requiring increased linkages to biodiversity conservation; 2. Ecological invasiveness, challenging our ability to find solutions to ecological aliens; 3. Individual variation, having applications in the conservation of rare species; 4. Movement of organisms, integrating ecological processes across landscapes and scales and addressing habitat fragmentation; and 5. Trophic-level interactions, driving ecological dynamics at the ecosystem-level. Addressing these will require cross-disciplinary research under the overarching framework of conservation ecology. PMID:23609103

Cristescu, Bogdan; Boyce, Mark S

2013-04-23

264

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

265

Focus on integrated quantum optics  

NASA Astrophysics Data System (ADS)

A key goal of research into quantum information processing is the development of technologies that are scaleable in complexity while allowing the mass manufacture of devices that promise transformative effects on information science. The demonstration that integrated photonics circuits could be made to perform operations that exploit the quantum nature of the photon has turned them into leading candidates for practical quantum information processing technologies. To fully achieve their promise, however, requires research from diverse fields. This focus issue provides a snapshot of some of the areas in which key advances have been made. We are grateful for the contributions from leading teams based around the globe and hope that the degree of progress being made in a challenging and exciting field is apparent from the papers published here.

O'Brien, Jeremy; Patton, Brian; Sasaki, Masahide; Vu?kovi?, Jelena

2013-03-01

266

Focus Issue: A Sharp Focus on Cell Signaling  

NSDL National Science Digital Library

Among the techniques used to study signal transduction, imaging and microscopy have the undeniable appeal of allowing the experimentalist to see cellular structures and--with the advent of new techniques in live-cell light microscopy--to visualize dynamic interactions among molecules in cell signaling pathways. This week's Science and Science's STKE collate material on imaging techniques in cell biology to bring this dynamic area into a sharp focus. Two Reviews in Science provide fundamental information on live-cell imaging. In an overview of live-cell imaging techniques, Stephens and Allan provide advice for researchers considering fluorescence microscopy and discuss such approaches as total internal reflection fluorescence microscopy (TIRFM), fluorescence resonance energy transfer (FRET), and photobleaching and photoactivation. In a complementary Review, Lippincott-Schwartz and Patterson trace the development and applications of green fluorescent protein (GFP) and its variants, which can be used to create chimeric proteins that can be expressed in cells and used to monitor protein localization and protein-protein interactions.

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

2003-04-08

267

An auto-focusing system for white light microscopic measurement  

Microsoft Academic Search

With the rapid development of semiconductor technology the demand for high resolution measuring system is evolving at an ever-increasing pace. Microscope was initially used to detect the defect by connecting charge couple device (CCD) as an auxiliary device. In general, for microscopic measurement human eyes are used to focus on the sample. The adjustment depends on the operator's astute measurement

Ming Chang; Juti Rani Deka; Pei Jung Chen; Yu Kuan Chen; Changcai Cui

2008-01-01

268

SWCX Emission from the Helium Focusing Cone - Preliminary Results.  

National Technical Information Service (NTIS)

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(s...

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

2008-01-01

269

Fine particle counting with aerodynamic particle focusing and corona charging  

Microsoft Academic Search

The conceptual design and evaluation of a fine particle sizing and counting instrument are introduced in this paper. A corresponding laboratory prototype was developed by coupling aerodynamic particle focusing with corona charging techniques that could detect particle sizes down to 25nm in diameter. Comparison between the prototype and a condensation particle counter (CPC) using identical monodisperse particles showed that the

Z. C. Tan; A. S. Wexler

2007-01-01

270

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

271

EDITORIAL: Focus on Attosecond Physics  

NASA Astrophysics Data System (ADS)

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

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

2008-02-01

272

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

273

SIAM Workshop: Focus on Diversity  

SciTech Connect

The Fourth SlAM Graduate Student Focus on Diversity workshop was held on July 12, 2000 at the Westin Rio Mar Hotel in Rio Grande, Puerto Rico. The Department of Energy provided partial support for this event. The day-long workshop consisted of several different activities. The meeting opened with a discussion of some data collected by the American Mathematical Society on Ph.D.'s awarded in the U.S. to citizens and non-citizens, further classified as blacks, latinos, asians and native americans. The activity continued with nine technical talks by underrepresented minority graduate students, informal luncheon and pizza breaks to foster social interaction, and an evening forum chaired by Dr. Richard Tapia (Rice University) in which issues related to the participation of minorities in national meetings and proposal writing where discussed. These sessions were open to the entire SIAM community and served to highlight the progress, achievements, and aspirations of the workshop participants. The students attended as well the three SlAM plenary talks during the day and the community lecture in the evening. The activity had a lively participation of students and representatives from various academic institutions and sponsoring agencies. In particular, we had the participation of 24 undergraduate students from the Mathematics REU program of the University of Puerto Rico at Humacao.

None

2000-07-12

274

Focus+context metro maps.  

PubMed

We introduce a focus+context method to visualize a complicated metro map of a modern city on a small displaying area. The context of our work is with regard the popularity of mobile devices. The best route to the destination, which can be obtained from the arrival time of trains, is highlighted. The stations on the route enjoy larger spaces, whereas the other stations are rendered smaller and closer to fit the whole map into a screen. To simplify the navigation and route planning for visitors, we formulate various map characteristics such as octilinear transportation lines and regular station distances into energy terms. We then solve for the optimal layout in a least squares sense. In addition, we label the names of stations that are on the route of a passenger according to human preferences, occlusions, and consistencies of label positions using the graph cuts method. Our system achieves real-time performance by being able to report instant information because of the carefully designed energy terms. We apply our method to layout a number of metro maps and show the results and timing statistics to demonstrate the feasibility of our technique. PMID:22034374

Wang, Yu-Shuen; Chi, Ming-Te

2011-12-01

275

Ballistic Focusing of Polyenergetic Protons Driven by Petawatt Laser Pulses  

SciTech Connect

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

Kar, S.; Borghesi, M.; Zepf, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN (United Kingdom); Markey, K. [Centre for Plasma Physics, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN (United Kingdom); Central Laser Facility, Rutherford Appleton Laboratory, OX11 0QX (United Kingdom); Carroll, D. C; McKenna, P.; Quinn, M. N. [SUPA, Department of Physics, University of Strathclyde, Glasgow, G4 0NG (United Kingdom); Neely, D. [Central Laser Facility, Rutherford Appleton Laboratory, OX11 0QX (United Kingdom)

2011-06-03

276

The Unfocused Focus Group: Benefit or Bane?  

ERIC Educational Resources Information Center

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

Franz, Nancy K.

2011-01-01

277

Fredholm's equations for subwavelength focusing  

NASA Astrophysics Data System (ADS)

Subwavelength focusing (SF) is a very useful tool that can be carried out with the use of left hand materials for optics that involve the range of the microwaves. Many recent works have described a successful alternative procedure using time reversal methods. The advantage is that we do not need devices which require the complicated manufacture of left-hand materials; nevertheless, the theoretical mathematical bases are far from complete because before now we lacked an adequate easy-to-apply frame. In this work we give, for a broad class of discrete systems, a solid support for the theory of electromagnetic SF that can be applied to communications and nanotechnology. The very central procedure is the development of vector-matrix formalism (VMF) based on exploiting both the inhomogeneous and homogeneous Fredholm's integral equations in cases where the last two kinds of integral equations are applied to some selected discrete systems. To this end, we first establish a generalized Newmann series for the Fourier transform of the Green's function in the inhomogeneous Fredholm's equation of the problem. Then we go from an integral operator equation to a vector-matrix algebraic one. In this way we explore the inhomogeneous case and later on also the very interesting one about the homogeneous equation. Thus, on the one hand we can relate in a simple manner the arriving electromagnetic signals with those at their sources and we can use them to perform a SF. On the other hand, we analyze the homogeneous version of the equations, finding resonant solutions that have analogous properties to their counterparts in quantum mechanical scattering, that can be used in a proposed very powerful way in communications. Also we recover quantum mechanical operator relations that are identical for classical electromagnetics. Finally, we prove two theorems that formalize the relation between the theory of Fredholm's integral equations and the VMF we present here.

Velázquez-Arcos, J. M.

2012-10-01

278

EDITORIAL: Focus on Molecular Electronics FOCUS ON MOLECULAR ELECTRONICS  

NASA Astrophysics Data System (ADS)

The notion 'molecular electronics' has been used more frequently since the 1970s and summarizes a series of physical phenomena and ideas for their application in connection with organic molecules, oligomers, polymers, organic aggregates and solids. The properties studied in this field were connected to optical and electrical phenomena, such as optical absorption, fluorescence, nonlinear optics, energy transport, charge transfer, electrical conductance, and electron and nuclear spin-resonance. The final goal was and is to build devices which can compete or surpass some aspects of inorganic semiconductor devices. For example, on the basis of organic molecules there exist rectifiers, transistors, molecular wires, organic light emitting diodes, elements for photovoltaics, and displays. With respect to applications, one aspect of the organic materials is their broad variability and the lower effort and costs for their processability. The step from microstructures to the investigation of nanostructures is a big challenge also in this field and has lead to what nowadays is called molecular electronics in its narrow sense. In this field the subjects of the studies are often single molecules, e.g. single molecule optical spectroscopy, electrical conductance, i.e. charge transport through a single molecule, the influence of vibrational degrees of freedom, etc. A challenge here is to provide the techniques for addressing in a reproducible way the molecular scale. In another approach small molecular ensembles are studied in order to avoid artefacts from particular contact situations. The recent development of the field is presented in [1 8]. In this Focus Issue we present new results in the field of 'molecular electronics', both in its broad and specialized sense. One of the basic questions is the distribution of the energy levels responsible for optical absorption on the one hand and for the transport of charge on the other. A still unanswered question is whether the Wannier exciton model applies in which the excitation is distributed over several molecules or whether a good description is given by the Frenkel exciton model with the electron and the whole being localized at the same molecular unit. In organic semiconductors the charge transport usually occurs on the basis of holes because of the presence of many defects giving rise to a localization of the electrons. It is therefore a challenge to produce materials with both positive and negative mobile charge carriers. In the 1990s V M Agranovich introduced the idea of hybrid excitons, i.e. of nanostructured materials consisting of both organic and inorganic semiconductors. At the interface between the organic and inorganic parts new excitons can appear, being a superposition of both Frenkel and Wannier excitons and having both the high oscillator strength of the Frenkel and the large optical nonlinearity of the Wannier exciton. The problem is to find optimum combinations of the organic and inorganic parts to enable the hybrid structure concept to work. Micro-cavities also play an important role in the investigation of organic materials resulting in a new state (polariton) as the superposition of a photon and an exciton because of the large exciton photon interaction. A similar excitation arises because of the interaction between plasmons and photons. A special geometrical shape of a nano-cavity increases the interaction between the electromagnetic radiation and a dipole sitting in the cavity. The interaction between vibronic degrees of freedom and electronic excitations plays an important role for various phenomena such as nonlinear processes, the question of coherence, information on the shape of a potential hypersurface, etc. With the help of femtosecond laser pulses, detailed information on such vibrations can be obtained. Also of great importance is the investigation of the energy transfer in artificial light-harvesting systems, e.g. in dendrimers. Finally the combination of experimental and theoretical investigations allows for a comparison of the spectra of two molecules wi

Scheer, Elke; Reineker, Peter

2008-06-01

279

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

280

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

281

Dark focus measured in Navy jet tactical fighter pilots.  

PubMed

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

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

1988-02-01

282

Cold Neutron Focusing with a Wolter Type-I Mirror  

NASA Astrophysics Data System (ADS)

A cold neutron beam from a research reactor was focused using a Wolter type-I mirror which was originally designed for X-ray imaging. The optical system was installed at JRR-3 of Japan Atomic Energy Agency (JAEA). Focused neutron images were taken at wavelengths of 0.6 nm to about 1 nm and they were detected by an imaging plate. The spatial resolution obtained at the focal plane was about 100 ?m, which was limited mainly by the pixel size of the imaging plate.

Aoki, Sadao; Yamamoto, Tsuyoshi; Furukawa, Jun

2012-02-01

283

Space charge effects with periodic focusing  

SciTech Connect

The dielectric response of a charged particle beam to a periodic focusing field enhances the effective focusing strength of the channel, reducing the matched beam radius and affecting the motion of halo particles. The dielectric response depends on the shape of the beam, the type of focusing and the ratio of the plasma frequency of the beam to the frequency of the focusing. TRACE 3-D is used to find the change in the effective focusing strength for a uniform-density beam in a quadrupole channel, showing agreement with theory for enhancements in the effective focusing strength of up to about 10{percent}. {copyright} {ital 1997 American Institute of Physics.}

Brown, N. [G. H. Gillespie Associates, Inc. P.O. Box 2961, Del Mar, California 92014 (United States)

1997-02-01

284

Space charge effects with periodic focusing  

SciTech Connect

The dielectric response of a charged particle beam to a periodic focusing field enhances the effective focusing strength of the channel, reducing the matched beam radius and affecting the motion of halo particles. The dielectric response depends on the shape of the beam, the type of focusing and the ratio of the plasma frequency of the beam to the frequency of the focusing. TRACE 3-D is used to find the change in the effective focusing strength for a uniform-density beam in a quadrupole channel, showing agreement with theory for enhancements in the effective focusing strength of up to about 10%.

Brown, Nathan [G. H. Gillespie Associates, Inc. P.O. Box 2961, Del Mar, California 92014 (United States)

1997-02-01

285

Sensors for process control Focus Team report  

SciTech Connect

At the Semiconductor Technology Workshop, held in November 1992, the Semiconductor Industry Association (SIA) convened 179 semiconductor technology experts to assess the 15-year outlook for the semiconductor manufacturing industry. The output of the Workshop, a document entitled ``Semiconductor Technology: Workshop Working Group Reports,`` contained an overall roadmap for the technology characteristics envisioned in integrated circuits (ICs) for the period 1992--2007. In addition, the document contained individual roadmaps for numerous key areas in IC manufacturing, such as film deposition, thermal processing, manufacturing systems, exposure technology, etc. The SIA Report did not contain a separate roadmap for contamination free manufacturing (CFM). A key component of CFM for the next 15 years is the use of sensors for (1) defect reduction, (2) improved product quality, (3) improved yield, (4) improved tool utilization through contamination reduction, and (5) real time process control in semiconductor fabrication. The objective of this Focus Team is to generate a Sensors for Process Control Roadmap. Implicit in this objective is the identification of gaps in current sensor technology so that research and development activity in the sensor industry can be stimulated to develop sensor systems capable of meeting the projected roadmap needs. Sensor performance features of interest include detection limit, specificity, sensitivity, ease of installation and maintenance, range, response time, accuracy, precision, ease and frequency of calibration, degree of automation, and adaptability to in-line process control applications.

Not Available

1993-09-01

286

Mapping of focused Laguerre-Gauss beams  

NASA Astrophysics Data System (ADS)

We study the detection of propagating optical fields bearing axial symmetry in the situation of an extreme focusing, when the paraxial approximation no longer holds. The results, obtained by general arguments based upon the vectorial nature of electromagnetic fields, show the rapid spatial variations of fields with ``complicated'' spatial structure [1]. Laguerre-Gauss beam, notably beams bearing a l = 2 orbital angular momentum for which a magnetic field and a gradient of the electric field are present on axis have been examined in their behavior upon an atomic size light detector sensitive to quadrupole electric transitions as well as to magnetic dipole transitions. nd apply it to the case of a Laguerre-Gauss beam.We detail how the mapping of such a beam depends on the nature and on the specific orientation of the detector. We also show that the interplay of mixing of polarization and topological charge, respectively associated to spin and orbital momentum when the paraxial polarization holds, modifies the apparent size of the beam in the focal plane.[0pt] [1]. V. Klimov, M. Ducloy, D. Bloch and JR Rios Leite, Phys. Rev. A 85, 053834 (2012).

Rios Leite, Jose R.; Klimov, Vasily; Ducloy, Martial; Bloch, Daniel

2013-03-01

287

Status of dark matter detection  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

288

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – When you first read the label, would you say your attention was focused ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

289

Researching Lifelong Learning Through Focus Groups  

Microsoft Academic Search

Focus group research is becoming a seriously hot topic. As a research method, the focused group interview is well established in the social sciences, dating back to Robert Merton's pioneering investigation of audience reactions to government information films during the Second World War. More recently, though, focus groups have been largely associated with market research. Among their many reported achievements,

John Field

2000-01-01

290

School-focused Inservice: Descriptions and Discussion.  

ERIC Educational Resources Information Center

|The characteristics and structures of school-focused inservice teacher education are explored by educators and researchers in 16 essays. An introductory article gives the rationale for more and better school-focused inservice education, particularly because of the Education for All Handicapped Children Act (Public Law 94-142). School-focused

Howey, Kenneth R., Ed.; And Others

291

Zoom lens without focus-breathing phenomena  

Microsoft Academic Search

Assuming that exit pupil position is fixed, it is presented a zoom lens having a focusing mechanism which does not give rise to any changes in the angular field of view. A frontal part set in front of the zooming part consists of two movable components for focusing. The paraxial condition in which no focus breathing phenomena exist is, in

Kazuo Tanaka

2001-01-01

292

Focus Groups: A Qualitative Opportunity for Researchers  

Microsoft Academic Search

This essay outlines focus groups as a relatively new method of research for the com munication and organizational researcher. The needs for this type of research, essen tial ingredients of a quality focus group session, and the advantages and disadvantages of the method are discussed. A theoretical framework is established and specific instances of the application of focus groups in

Peggy Yuhas Byers; James R. Wilcox

1991-01-01

293

FOCUS GROUP RESEARCH IN THE COMMUNITY COLLEGE  

Microsoft Academic Search

Focus group research is a qualitative research tool well suited for community colleges. Focus group research appears to be a quick and easy means of staying abreast of the educational needs and expectations of the college community. To be successful and avoid inherent pitfalls, however, focus group research should follow three guidelines: (1) College?wide administrative procedures should be established; (2)

Isa N. Engleberg; Marlene C. Cohen

1989-01-01

294

Evaluation of focusing solar energy collectors  

Microsoft Academic Search

An introductory presentation is made concerning means of evaluating the performance of focusing solar energy collectors, with emphasis on common features among different focusing collectors. Term definitions, the advantages of focusing collectors, over flat-plate collectors methods of concentration, an illustrative example, and an economic evaluation criterion are discussed. It is concluded that the key information necessary to evaluate a collector

F. Kreith

1975-01-01

295

Using Focus Groups To Explore Student Opinion.  

ERIC Educational Resources Information Center

This paper discusses the use of focus groups to investigate criteria used by college students to determine their satisfaction with higher education, and presents the results of a pilot study. It reviews research on the use of focus groups, discusses the development of a focus group guide for the current study, and examines problems associated with…

Franklin, Kathy Kramer; Knight, W. Hal

296

High intensity focused ultrasound lithotripsy with cavitating microbubbles  

Microsoft Academic Search

In the medical ultrasound field, microbubbles have recently been the subject of much interest. Controlling actively the effect\\u000a of the microbubbles, a novel therapeutic method has been investigated. In this paper, our works on high intensity focused\\u000a ultrasound (HIFU) lithotripsy with cavitating microbubbles are reviewed and the cavitation detection method to optimize the\\u000a HIFU intensity is investigated. In the HIFU

Shin Yoshizawa; Teiichiro Ikeda; Akira Ito; Ryuhei Ota; Shu Takagi; Yoichiro Matsumoto

2009-01-01

297

Probing Nonperturbative QED with Optimally Focused Laser Pulses  

NASA Astrophysics Data System (ADS)

We study nonperturbative pair production in intense, focused laser fields called e-dipole pulses. We address the conditions required, such as the quality of the vacuum, for reaching high intensities without initiating beam-depleting cascades, the number of pairs which can be created, and experimental detection of the created pairs. We find that e-dipole pulses offer an optimal method of investigating nonperturbative QED.

Gonoskov, A.; Gonoskov, I.; Harvey, C.; Ilderton, A.; Kim, A.; Marklund, M.; Mourou, G.; Sergeev, A.

2013-08-01

298

Nonthermal ablation with microbubble-enhanced focused ultrasound close to the optic tract without affecting nerve function.  

PubMed

Object Tumors at the skull base are challenging for both resection and radiosurgery given the presence of critical adjacent structures, such as cranial nerves, blood vessels, and brainstem. Magnetic resonance imaging-guided thermal ablation via laser or other methods has been evaluated as a minimally invasive alternative to these techniques in the brain. Focused ultrasound (FUS) offers a noninvasive method of thermal ablation; however, skull heating limits currently available technology to ablation at regions distant from the skull bone. Here, the authors evaluated a method that circumvents this problem by combining the FUS exposures with injected microbubble-based ultrasound contrast agent. These microbubbles concentrate the ultrasound-induced effects on the vasculature, enabling an ablation method that does not cause significant heating of the brain or skull. Methods In 29 rats, a 525-kHz FUS transducer was used to ablate tissue structures at the skull base that were centered on or adjacent to the optic tract or chiasm. Low-intensity, low-duty-cycle ultrasound exposures (sonications) were applied for 5 minutes after intravenous injection of an ultrasound contrast agent (Definity, Lantheus Medical Imaging Inc.). Using histological analysis and visual evoked potential (VEP) measurements, the authors determined whether structural or functional damage was induced in the optic tract or chiasm. Results Overall, while the sonications produced a well-defined lesion in the gray matter targets, the adjacent tract and chiasm had comparatively little or no damage. No significant changes (p > 0.05) were found in the magnitude or latency of the VEP recordings, either immediately after sonication or at later times up to 4 weeks after sonication, and no delayed effects were evident in the histological features of the optic nerve and retina. Conclusions This technique, which selectively targets the intravascular microbubbles, appears to be a promising method of noninvasively producing sharply demarcated lesions in deep brain structures while preserving function in adjacent nerves. Because of low vascularity-and thus a low microbubble concentration-some large white matter tracts appear to have some natural resistance to this type of ablation compared with gray matter. While future work is needed to develop methods of monitoring the procedure and establishing its safety at deep brain targets, the technique does appear to be a potential solution that allows FUS ablation of deep brain targets while sparing adjacent nerve structures. PMID:24010975

McDannold, Nathan; Zhang, Yong-Zhi; Power, Chanikarn; Jolesz, Ferenc; Vykhodtseva, Natalia

2013-09-06

299

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.

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

2009-01-01

300

Detective Fiction.  

ERIC Educational Resources Information Center

Intended for reluctant readers as well as for readers with a special interest in detective stories, this high school English course consists of the following eight units: the history of detective fiction, the psychology of violent crime, crime and society, the procedures of crime detection, the mind of the detective, analysis of the detective

Morris Hills Regional School District, Rockaway, NJ.

301

Automatic focusing techniques for infrared sensors  

NASA Astrophysics Data System (ADS)

In this paper we study passive focusing techniques for infrared sensors. We present a survey of existing focus measures, i.e. functionals that give an estimate of the quality of focus as a function of the lens position. We synthesize the material proposed in the literature and show that all the approaches exploit the same general layout differing only for the choice of the filtering technique used to extract the image details. We present and discuss experimental results obtained on real infrared data taken in many operating conditions. The experimental analysis aims at comparing the quality of the focus measures and at evaluating their impact of the subsequent algorithm that searches the best focus position of the lens. For this purpose, we propose a comparative analysis based on three important properties of the focus measure: symmetry, smoothness and peakdness.

Masini, Andrea; Diani, Marco; Corsini, Giovanni; Porta, Antonio; Romagnoli, Marco

2007-11-01

302

Focusing effects in predecisional information acquisition.  

PubMed

Legrenzi et al. [Legrenzi, P., Girotto, V., & Johnson-Laird, P. N. (1993). Focusing in reasoning and decision making. Cognition, 49, 37-66] showed that when a single option is proposed for consideration the decision makers limit their information acquisition to this one option, failing to take into account potential alternatives. Unfortunately, the evidence supporting this focusing effect is weak and its determinants are largely unknown. In three experiments, we provided stronger support for the reality of the focusing effect and we identified two significant determinants of this phenomenon. The results show that both representational and value-related manipulations are able to reduce the effect. Results also suggest the need to distinguish between two different types of focusing: representational focusing and search-related focusing. PMID:16919591

Del Missier, Fabio; Ferrante, Donatella; Costantini, Erica

2006-08-21

303

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

304

[The notion of task in focus groups].  

PubMed

The aim of this paper is to revisit the concept of task in light of Pichon-Riviére's referential and to discuss its application in research with focus groups. Focus groups are understood as a research technique which proposes to investigate a topic in depth, allowing the construction of new ideas and answers on the subject in focus. The presuppositions of operative groups were used to support the research practice with focus groups. In these, the notion of task has a key strategic position from which it seeks to intervene in society through dialogue and collective construction, unlike simple data collecting PMID:22737812

Dall'Agnol, Clarice Maria; de Magalhães, Ana Maria Müller; Mano, Gustavo Caetano de Mattos; Olschowsky, Agnes; da Silva, Flávia Pacheco

2012-03-01

305

Manipulating Regulatory Focus in Cigarette Smokers  

PubMed Central

Regulatory focus theory (RFT; Higgins, 1997) may help to address the issue of motivation in cigarette smoking cessation. RFT suggests that individuals may be motivated to approach desired end-states (e.g., improved lung capacity) and/or avoid undesired end-states (e.g., illness). These motivations are referred to as promotion focus, in which people attempt to achieve their aspirations, and prevention focus, in which people are motivated to live up to responsibilities. According to RFT, smoking-related messages framed to match an individual's regulatory focus should be more effective than those that do not match. The current study attempted to prime promotion and prevention focus in a sample of cigarette smokers, to determine if priming impacts memory for smoking-related narratives. We expected that participants in the promotion-focus condition would outperform those in the prevention-focus condition on recall of materials reflecting approach strategies, whereas those in the prevention-focus condition would score better on recall of vignettes depicting avoidance. This hypothesis was not supported. There was, however, a significant interaction between participants' recall of vignettes depicting smoking vs. abstaining and approach vs. avoidance strategies, such that participants recalled smoking vignettes better when the described-person's goal was smoking to avoid an undesired state and recalled abstaining vignettes better when the target's goal was to approach a desired state. Further research into how regulatory focus theory may apply to adult cigarette smokers is warranted.

Friedman-Wheeler, Dara G.; Rizzo-Busack, Hilda; McIntosh, Elizabeth; Ahrens, Anthony H.; Haaga, David A. F.

2010-01-01

306

IMAGING: Focusing light in scattering media  

PubMed Central

Combining ultrasonic modulation and optical phase conjugation allows light to be tightly focused in a scattering medium, providing benefits for studies of photophysical, photochemical and photobiological processes

Konecky, Soren D.; Tromberg, Bruce J.

2011-01-01

307

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – Remember the warnings. Statistics. N. ... Remember the warnings. Frequency. ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

308

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – Time spent reading ... Time spent reading food label (seconds). Frequency. ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

309

Focusing polychromatic light through strongly scattering media.  

PubMed

We demonstrate feedback-optimized focusing of spatially coherent polychromatic light after transmission through strongly scattering media, and describe the relationship between optimized focus intensity and initial far-field speckle contrast. Optimization is performed using a MEMS spatial light modulator with camera-based or spectrometer-based feedback. We observe that the spectral bandwidth of the optimized focus depends on characteristics of the feedback signal. We interpret this dependence as a modification in the number of independent frequency components, or spectral correlations, transmitted by the sample, and introduce a simple model for polychromatic focus enhancement that is corroborated by experiment with calibrated samples. PMID:23938576

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

2013-07-15

310

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – Recognize any adverse (bad) reactions. Statistics. N. Valid. Missing. ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

311

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

Microsoft Academic Search

Three-dimensional (3D) study of cancellous bone tissue organization is necessary to understand how modelling and remodelling processes regulate bone structure and connectivity. It requires imaging methods that have both suf- ficient resolution power and width and depth of field. Since clinical imaging methods fall far short of the first requirement, we can only study prepared tissue in isolation from the

Alan Boyde

2003-01-01

312

Pedestrian Detection.  

National Technical Information Service (NTIS)

Pedestrian detection has been an active topic for several years. Many types of sensors and algorithms have been explored to improve pedestrian detection with varying levels of success. Currently, the pedestrian detection program within the Intelligent Sys...

M. Del Rose P. Frederick

2005-01-01

313

Voltage-controlled separation of proteins by electromobility focusing in a dialysis hollow fiber  

Microsoft Academic Search

Electromobility focusing (EMF) is a relatively new protein separation technique that utilizes an electric field gradient and a hydrodynamic flow. Proteins are focused in order of electrophoretic mobility at points where their electrophoretic migration velocities balance the hydrodynamic flow velocity. Steady state bands are formed along the separation channel when equilibrium is reached. Further separation and detection can be easily

Qinggang Wang; Shu-Ling Lin; Karl F. Warnick; H. Dennis Tolley; Milton L. Lee

2003-01-01

314

Focus Issue: From Input to Output--Are All Paths Equal?  

NSDL National Science Digital Library

Science and Science Signaling team up to explore the properties of signaling networks. Science focuses on feedback loops, new techniques for detecting such processes, and how these influence signaling outcomes (http://www.sciencemag.org/cellsignaling08/). Science Signaling focuses on systems-level understanding of signaling networks with an emphasis on explaining how input signals are interpreted to generate various responses.

Nancy R. Gough (American Association for the Advancement of Science;Science Signaling REV)

2008-10-21

315

Vertical focusing device utilizing dielectrophoretic force and its application on microflow cytometer  

Microsoft Academic Search

Focusing of particles\\/cells in the vertical direction inside a micromachined flow cytometer is a critical issue while using an embedded optical detection system aligned with microchannels. Even if the particles\\/cells have been focused centrally in the horizontal direction using coplanar sheath flows, appreciable errors may still arise if they are randomly distributed in the vertical direction. This work presents a

Che-Hsin Lin; Gwo-Bin Lee; Lung-Ming Fu; Bao-Herng Hwey

2004-01-01

316

Haptoglobin phenotyping by polyacrylamide gel isoelectric focusing and its application to simultaneous typing of serum proteins  

Microsoft Academic Search

A simple isoelectric focusing method for haptoglobin (HP) typing is described. Serum was pretreated first with C. perfringens neuraminidase (CPN) and then with dithiothreitol (DTT). The treated serum was subjected to polyacrylamide gel isoelectric focusing (PAGIF), and the band patterns were detected by immunoblotting. The method could be successfully applied to HP typing of bloodstains as old as 2 months.

M. Fukuda; Y. Tamaki; T. Kishida

1988-01-01

317

Study of electron focusing in thick GEM based photon detectors using semitransparent photocathodes  

NASA Astrophysics Data System (ADS)

The detection efficiency of a GEM based UV sensitive gaseous photomultiplier (GPM) depends on the focusing of electrons from the drift gap to the GEM aperture. We have studied the effect of drift parameters on the efficiency of electron focusing into Thick GEM (THGEM) holes in a GPM with semitransparent UV photoconverter. This study comprises simulation of electron focusing into THGEM holes using GARFIELD for different Ar and Ne based gas mixtures and experimental investigations of the same with P10 gas mixture.

Baishali, G.; Radhakrishna, V.; Koushal, V.; Rakhee, K.; Rajanna, K.

2013-11-01

318

Second-order focusing parallel electron energy magnetic sector analyzer designs  

Microsoft Academic Search

This paper presents parallel magnetic sector analyzer designs that are predicted to have second-order or better focusing properties. Simulation results indicate that by reducing the gap between excitation plates in a compact parallel energy magnetic sector box design, second-order focusing regions in the detected energy spectrum can be obtained. A method for combining a first-order focusing magnetic box sector unit

Anjam Khursheed

2011-01-01

319

A new method of target focused sound  

Microsoft Academic Search

In this paper, a new method of using advance beamforming algorithm is proposed to control target focused found. The advance beamforming algorithm that adjusts the timing of sound waves emitted from each speaker in an array. As a result, sound waves cancel each other out in some parts of space, and amplify each other in others, effectively creating a focused

Daguang Jiang; Junkai Yi; Gaohui Bian

2011-01-01

320

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…

Saban, Kenneth A.

321

Saved by focused echo evaluation in resuscitation.  

PubMed

A 74-year-old woman received thrombolysis for pericarditis. She subsequently developed shock and cardiac arrest. The case report describes the events of how a simple immediate bedside focused echo proved to be a life saving assessment. Current availability and training issues in focused transthoracic echo are discussed. PMID:22002526

Hollister, N; Bond, R; Donovan, A; Nicholls, B

2011-11-01

322

Saved by focused echo evaluation in resuscitation.  

PubMed

A 74-year-old woman received thrombolysis for pericarditis. She subsequently developed shock and cardiac arrest. The case report describes the events of how a simple immediate bedside focused echo proved to be a life saving assessment. Current availability and training issues in focused transthoracic echo are discussed. PMID:22707666

Hollister, N; Bond, R; Donovan, A; Nicholls, B

2011-03-08

323

THE FOCUS GROUP A QUALITATIVE RESEARCH METHOD  

Microsoft Academic Search

Abstract The Focus Group ( FG) has been actually employed by marketing, and is becoming importanct also in other areas; such as, education, health, management, decision-making, and information systems, among others. Depending on the research objective, the Focus Groupcan be used alone or in conjunction with other methods. The results obtained from the FGapplication are particularly effective in supplying information

Henrique Freitas; Mírian Oliveira; Civil Engineer; Milton Jenkins; Oveta Popjoy

324

Methods in safety pharmacology in focus  

Microsoft Academic Search

This focused issue of the Journal of Pharmacological and Toxicological Methods is the fifth to highlight Methods in Safety Pharmacology and includes a number of articles from the 7th Annual Safety Pharmacology Society (SPS) meeting that was held in Edinburgh, Scotland, September 19–21, 2007. However, unlike issues of the past, in which content predominantly focused on cardiovascular issues (specifically QT

Michael K. Pugsley; David J. Gallacher; Rob Towart; Simon Authier; Michael J. Curtis

2008-01-01

325

New Focus, New Challenge [From the Editor  

Microsoft Academic Search

Rapid advancement of our information society necessitates prompt update and expansion of the technical scope and focus of interest of our IEEE Signal Processing Society (SPS). Compared with just some years ago, the current focus of signal processing as an enabling technology has been significantly broadened. Now it encompasses theories, architectures, algorithms, implementations, and applications for the transformation of information

Li Deng

2010-01-01

326

Focus Group Interview in Family Practice Research  

PubMed Central

Focus group interviews, described as a qualitative research method with good potential in family medicine, are traced from their origins in market research to their growing role in sociology and medicine. Features of this method are described, including design, conduct, and analysis. Both proven and potential areas for primary care research using focus groups are outlined.

Wood, Marjorie L.

1992-01-01

327

Final Focus Test Facility ATF2 Status  

Microsoft Academic Search

ATF2 is a final-focus test beam line which aims to focus the low emittance beam from the ATF damping ring to a vertical size of about 37 nm and to demonstrate nanometre level beam stability. Several advanced beam diagnostics and feedback tools are used. In December 2008, construction and installation were completed and beam commissioning started, supported by an international

P. Bambade; A. Seryi; T. Tauchi

2012-01-01

328

An auto-focusing CCD camera mount  

NASA Astrophysics Data System (ADS)

The traditional methods of focusing a CCD camera are either time consuming, difficult or, more importantly, indecisive. This paper describes a device designed to allow the observer to be confident that the camera will always be properly focused by sensing a selected star image and automatically adjusting the camera's focal position.

Arbour, R. W.

1994-08-01

329

Attentional Focus Effects in Balance Acrobats  

ERIC Educational Resources Information Center

|Performing and learning motor skills has been shown to be enhanced if the performer adopts an external relative to internal focus (or no focus) of attention (Wulf, 2007). The present study examined the generalizability of this effect to top-level performers (balance acrobats). Participants performed a balance task (standing on an inflated rubber…

Wulf, Gabriele

2008-01-01

330

Revising Safety Instructions with Focus Groups  

Microsoft Academic Search

This article analyzes the use of focus groups for the evaluation of a safety manual. To avoid one of the possible disadvantages of using focus groups, namely, sequencing or dominance problems, the method was combined with a troubleshooting text evaluation method: the plus-minus method. The combined approach produced valuable information about complex acceptance and relevance problems—information that could not easily

RIEN ELLING

1997-01-01

331

On FOCUS: Photographs and Writings by Students.  

ERIC Educational Resources Information Center

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

Strohmeyer, Beatriz; McGrail, Loren

332

Focused force angioplasty Theory and application  

SciTech Connect

Focused force angioplasty is a technique in which the forces resulting from inflating an angioplasty balloon in a stenosis are concentrated and focused at one or more locations within the stenosis. While the technique has been shown to be useful in resolving resistant stenoses, its real value may be in minimizing the vascular trauma associated with balloon angioplasty and subsequently improving the outcome.

Solar, Ronald J.; Ischinger, Thomas A

2003-03-01

333

Interactive data visualization using focusing and linking  

Microsoft Academic Search

This paper discusses two basic principles for interactive visualization of high dimensional data: focusing and linking. The paper and the accompanying video give examples of how graphical data analysis methods based on focusing and linking are used in applications including linguistics, geographic information systems, time series analysis, of multi-channel images arising in radiology and remote sensing.

Andreas Buja; John Alan McDonald; John Michalak; Werner Stuetzle

1991-01-01

334

Focus groups in nursing research: methodological perspectives.  

PubMed

Focus groups have been increasingly used as a data collection method in nursing research. The key feature of focus groups is the active interaction among participants to explore their views and opinions. In this respect, focus groups are distinct from other methods such as Delphi groups, nominal groups, brainstorming, and consensus panels, which seek to determine a consensus between participants. Compared with other data collection methods, it can be concluded that the real strength of focus groups is not simply in exploring what participants have to say, but in providing insights into the sources of complex behaviors and motivations. The aim of this paper is to present an overview of the focus group as a research tool in nursing research, particularly in nursing education. PMID:22464693

Jayasekara, Rasika S

2012-03-29

335

An auto-focusing system for white light microscopic measurement  

NASA Astrophysics Data System (ADS)

With the rapid development of semiconductor technology the demand for high resolution measuring system is evolving at an ever-increasing pace. Microscope was initially used to detect the defect by connecting charge couple device (CCD) as an auxiliary device. In general, for microscopic measurement human eyes are used to focus on the sample. The adjustment depends on the operator's astute measurement ability, which affected the repeatability and accuracy of the readings. There is a need of high-speed microscope auto focusing system for industrial applications. The present investigation describes about the development of an autofocus system to carry out microscopic measurement more precisely and accurately with less time. The measurement system consists of a light source, two beam splitters, a movable sample stage and a Mirau's interferometer, a photo-detector and 8051 microcontroller (MCU89C51). The light reflected from the sample surface interferes with the light reflected from the reference and produce an interference pattern, which is imaged onto a CCD array. In the setup developed for the autofocus one extra beam splitter is placed in the path of interfered beam to the CCD. The beam splitter is placed at equal distances from the CCD and the photodetector. The focus position is determined from the voltage developed in the photo-detector due to the movement of sample stage of the microscope. The maximum voltage that obtained at the focus position is confirmed with the CCD image. Microcontroller is used to stop the controller at the focus position immediately once the sample stage reaches it. Software is developed to locate the maximum intensity position. The design may autofocus the interferometer within 4mm distance in 1 second. The auto-focusing not only provides enhanced repeatability and accuracy of the results at a faster rate but also minimizes operator involvement.

Chang, Ming; Deka, Juti Rani; Chen, Pei Jung; Chen, Yu Kuan; Cui, Changcai

2008-12-01

336

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

337

NICMOS Focus and PAM Grid Tilt Tests  

NASA Astrophysics Data System (ADS)

The purpose of this proposal is determine the PAM settings corresponding to best focus for NIC1 and NIC2. A test will aslo be done on NIC3 in order to establish that the nominal PAM position of -9.5mm relative to mechanical zero results in an acceptable focus. The program consists of: Visit 01: Focus sweep using NIC1 Visit 02: Focus sweep using NIC2 Visit 03: Focus sweep using NIC3 Visit 04: Uplink of revised PAM settings {if needed} Visit 05: PAM X/Y grid tilt for NIC1 Visit 06: PAM X/Y grid tilt for NIC2 Visit 07: PAM X/Y grid tilt for NIC3 Visit 08: Uplink of revised PAM X/Y parameters {if needed} The focus sweeps are based on the normal focus monitoring proposal 11320. The tilt grid measurements are based on proposal 8977 {NIC1} and 9645 {NIC2 and NIC3}. The activity ID is NICMOS-05.;

Wiklind, Tommy

2008-07-01

338

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, Charles S. (Fremont, CA)

1993-01-01

339

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

340

Regulatory focus and attitudes to migrants.  

PubMed

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 gains. On the other hand, prevention-focused self-regulation is concerned with security needs and is directed at meeting duties and obligations. As such, it results in sensitivity to negative outcome and relative pain from losses. In Study 1, as predicted, the extent of promotion focus (i.e., a concern with accomplishment and the pursuit of ideals) predicted more positive attitudes to culturally similar and economically beneficial migrants, whereas the extent of prevention focus (i.e., concern with security and meeting obligations) predicted more negative attitudes to migrants who are culturally dissimilar. In Study 2 we replicated and extended these findings, showing that the extent of promotion focus and a lack of concern with threats predicted positive attitudes to both culturally similar and economically beneficial migrants, which, in the case of the latter group, was mediated by a focus on the benefits these migrants provide. In the case of culturally dissimilar migrants, the extent of promotion focus and a concern with gains predicted more positive attitudes. However, for economically less beneficial migrants, neither the extent of promotion nor prevention focus was a predictor. Only lower concerns with threat predicted more positive attitudes to this migrant group. The results are discussed with respect to other determinants of attitudes to migrants and the implications for migration and asylum-seeker policy. PMID:22043932

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

2010-06-01

341

Three-dimensional hydrodynamic focusing in a microfluidic Coulter counter  

NASA Astrophysics Data System (ADS)

Electrical impedance-based particle detection or Coulter counting, offers a lab-on-chip compatible method for flow cytometry. Developments in this area will produce devices with greater portability, lower cost, and lower power requirements than fluorescence-based flow cytometry. Because conventional Coulter apertures are prone to clogging, hydrodynamic focusing improves the device by creating fluid-walled channels with variable width to increase sensitivity without the associated risk of blocking the channel. We describe a device that focuses the sample in three dimensions, creating a narrow sample stream on the floor of the channel for close interaction with sensing electrodes. The key to this design is a stepped outlet channel fabricated in a single layer with soft lithography. In contrast to previous impedance-based designs, the new design requires minimal alignment with the substrate. Three-dimensional focusing maximizes the sensitivity of the device to cell-size particles within much larger channels. Impedance-based particle sensing experiments within this device show an increase in percentage conductivity change by a factor of 2.5 over devices that only focus the sample in the horizontal direction.

Scott, R.; Sethu, P.; Harnett, C. K.

2008-04-01

342

Isoelectric focusing in a microfluidically defined electrophoresis channel.  

PubMed

A new form of microchip isoelectric focusing that allows efficient coupling with pretreatment processes is reported. The sample is conveyed in a carrier ampholyte solution to the separation channel that is connected at both ends by two V-shaped lead channels, which supply electrode solutions to the connection point and complete the electrical connection to off-chip electrodes. The relatively high electric conductivity of the electrode solutions compared with that of the pH gradient enables focusing with a 2% loss of applied voltage at the electrodes using the lead channels. A glass microchip was constructed specifically for this configuration. The channel wall was coated with polydimethylacrylamide, and the IEF chip was operated in a chip holder equipped with on-chip connector valves. A plug of fluorescence-labeled peptide p I markers with p I values ranging from 3.64 to 9.56 with carrier ampholyte solution (pH 3-10) was introduced into the separation channel. When the plug reached the channel segment (24 mm in length) between the connection points with the electrolyte lead channels, isoelectric focusing was started after filling the lead channels with electrolyte solutions. The peptide markers were observed using scanning fluorescence detection. The entire range of the pH gradient was established in the segment after approximately 2 min. Isoelectric focusing of three consecutively injected sample plugs containing different p I markers was demonstrated. PMID:18407668

Shimura, Kiyohito; Takahashi, Katsuyoshi; Koyama, Yutaka; Sato, Kae; Kitamori, Takehiko

2008-04-12

343

Focused ion beam source method and apparatus  

DOEpatents

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

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

2000-01-01

344

Integration of Single Ion Implantation Method in Focused Ion Beam System for Nanofabrication  

Microsoft Academic Search

A method of single ion implantation based on the online detection of individual ion impacts on a pure silicon substrate has been implemented in a focused ion beam (FIB) system. The optimized silicon detector integrated with a state-of-art low noise electronic system and operated at a low temperature makes it possible to achieve single ion detection with a minimum energy

Changyi Yang; David N. Jamieson; Sean Hearne; Toby Hopf; Chris Pakes; S teven Prawer; Søren E. Andresen; Andrew Dzurak; E. Gauja; F. E. Hudson; R. G. Clark

2006-01-01

345

Energy analysis of fast ions from plasma focus discharges  

NASA Astrophysics Data System (ADS)

A Thomson parabola spectrometer was developed and used for energy and mass analysis of the fast ions emitted by a plasma focus. The design of the spectrometer, the detection system using cellulose nitrate films error analysis, and the calibration and test procedure are described. Besides deuterons, results reveal the presence in the emitted flux of highly ionized impurity ions which attain energies up to 18 MeV. Their energy distribution is consistent with acceleration in an electric field reaching 4 MV/mm. The deuteron distribution is shown to depend on the filling pressure. Besides use as an intense neutron source, the plasma focus can be used as a heavy ion accelerator provided the heavy ion yield can be increased.

Mozer, A.

1980-09-01

346

Pediatric Focused Safety Review: Ofirmev (acetaminophen ...  

Center for Biologics Evaluation and Research (CBER)

Text VersionPage 1. 1 Pediatric Focused Safety Review: OfirmevTM (acetaminophen injection) ... Page 24. 24 Intravenous Acetaminophen Medication Errors ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

347

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – This product may make ulcers worse. ... This product may make ulcers worse. ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

348

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – People with stomach ulcers can use this product. Statistics. N. Valid. Missing ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

349

Hydrodynamic focusing of a particle flux  

SciTech Connect

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

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

1995-12-01

350

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – Means a lot to me. Statistics. N. ... Means a lot to me, 303, 0. Means a lot to me. ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

351

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – Imagine you have a child, age 15. ... 303, 0. Imagine you have a child, age 15. ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

352

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

353

Focus Issue: A Niche of One's Own  

NSDL National Science Digital Library

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

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

2008-05-27

354

Family Preservation (Family Focus Research Project).  

National Technical Information Service (NTIS)

The Family Focus Research project provided a comprehensive evaluation of home-based crisis intervention strategies for families with children at risk of placement into substitute care. It examined the relative costs and benefits of three types of brief, i...

J. R. Taplin C. Rowland

1983-01-01

355

Periodic magnetic focusing of sheet electron beams  

SciTech Connect

Sheet electron beams focused by periodically cusped magnetic (PCM) fields are stable against low-frequency velocity-shear instabilities (such as the diocotron mode). This is in contrast to the more familiar unstable behavior in uniform solenoidal magnetic fields. A period-averaged analytic model shows that a PCM-focused beam is stabilized by ponderomotive forces for short PCM periods. Numerical particle simulations for a semi-infinite sheet beam verify this prediction and also indicate diocotron stability for long PCM periods is less constraining than providing for space-charge confinement and trajectory stability in the PCM focusing system. In this article the issue of beam matching and side focusing for sheet beams of finite width is also discussed. A review of past and present theoretical and experimental investigations of sheet-beam transport is presented.

Booske, J.H.; Basten, M.A.; Kumbasar, A.H. (Electrical and Computer Engineering, University of Wisconsin---Madison, Madison, Wisconsin 53706 (United States)); Antonsen, T.M. Jr.; Bidwell, S.W.; Carmel, Y.; Destler, W.W.; Granatstein, V.L.; Radack, D.J. (Laboratory for Plasma Research, University of Maryland, College Park, Maryland 20742-3511 (United States))

1994-05-01

356

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

357

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – Know when to stop taking the drug. ... Know when to stop taking the drug. ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

358

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – How much do you like the format or layout of the label? Statistics. N. Valid. ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

359

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Reliever Questionnaire Items: Focused Attention – What about a person who is considering taking this product but is under a doctor's care for high ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

360

Frequencies for Pain Reliever Questionnaire Items: Focused ...  

Center for Drug Evaluation (CDER)

... Frequencies for Pain Reliever Questionnaire Items: Focused Attention – People taking medications for high blood pressure should ask a doctor ... More results from www.fda.gov/drugs/developmentapprovalprocess/developmentresources

361

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

362

Generation of arbitrarily focused images by using multiple differently focused images  

NASA Astrophysics Data System (ADS)

In the paper, we propose a novel method of arbitrarily focused image acquisition using multiple differently focused images. First, we describe our previous select-and-merge method for all-focused image acquisition. We can get god results by using this method but it's not easy to extend this method for generating arbitrarily focused images. Then, based on the assumption that depth of the scene changes stepwise, we derive a formula for reconstruction between the desired arbitrarily focused image and multiple acquired images; we can reconstruct the arbitrarily focused image by iterative use of the formula. We also introduce coarse-to- fine estimation of PSFs of the acquired images. We show we can reconstruct arbitrarily focused images for a natural scene. In other words, we can simulate virtual cameras and synthesize images focused on arbitrarily depths.

Kodama, Kazuya; Aizawa, Kiyoharu; Hatori, Mitsutoshi

1997-01-01

363

Market-focused sustainability: market orientation plus!  

Microsoft Academic Search

The concept of sustainability is increasingly being addressed theoretically by scholars and practically by managers and policymakers.\\u000a With this growing focus on sustainability efforts, marketing is in a unique position to elevate its focus from managing relationships\\u000a with customers to strategically managing a broader set of marketplace issues. Overall, an organization achieves market-based\\u000a sustainability to the extent that it strategically

G. Tomas M. Hult; M. Hult

2011-01-01

364

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

365

Plasma Lenses for Heavy Ion Beam Focusing  

Microsoft Academic Search

At the German heavy-ion accelerator facility SIS\\/ESR at GSI in Darmstsdt intense heavy-ion beams are used to achieve high-energy deposition power in matter. For cffi- cient use of available beam power, beams have to be fo- cused to small spot sizes on the target. One key prob- lem is the fine-focusing of heavy-ion beams in order to achieve a focus

E. Boggasch; K.-G. Dietrich; A. Tauschwitz; D. H. H. Hoffmann; W. Laux; H. Wahl GSI-Darmstadt; Darmstadt R. Tkotz; M. Stetter

366

Point-focus solar concentrator technology  

Microsoft Academic Search

Acurex Corporation is developing state-of-the-art and advanced technology point-focus solar concentrators. The concentrators are intended for use in a modular, distributed solar thermal system capable of generating electricity or providing thermal power for small community, industrial, and isolated applications. The overall point-focus concentrator design is summarized and both state-of-the-art and advanced technology reflective panel design approaches are detailed. Test results

R. Bedard; P. Overly; D. Bell

1981-01-01

367

Focused force angioplasty: theory and application.  

PubMed

Focused force angioplasty is a technique in which the forces resulting from inflating an angioplasty balloon in a stenosis are concentrated and focused at one or more locations within the stenosis. While the technique has been shown to be useful in resolving resistant stenoses, its real value may be in minimizing the vascular trauma associated with balloon angioplasty and subsequently improving the outcome. PMID:12892774

Solar, Ronald J; Ischinger, Thomas A

368

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

369

Focus-distance-controlled 3D TV  

NASA Astrophysics Data System (ADS)

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

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

1996-09-01

370

Focus-distance-controlled 3D TV  

NASA Astrophysics Data System (ADS)

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

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

1997-05-01

371

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

372

Fast and Adaptive Auto-focusing Microscope  

NASA Astrophysics Data System (ADS)

Optical microscopes are widely used in biological and medical researches. By using the microscope, we can observe cellular movements including intracellular ions and molecules tagged with fluorescent dyes at a high magnification. However, a freely motile cell easily escapes from a 3D field of view of the typical microscope. Therefore, we propose a novel auto-focusing algorithm and develop a auto-focusing and tracking microscope. XYZ positions of a microscopic stage are feedback controlled to focus and track the cell automatically. A bright-field image is used to estimate a cellular position. XY centroids are used to estimate XY positions of the tracked cell. To estimate Z position, we use a diffraction pattern around the cell membrane. This estimation method is so-called Depth from Diffraction (DFDi). However, this method is not robust for individual differences between cells because the diffraction pattern depends on each cellular shape. Therefore, in this study, we propose a real-time correction of DFDi by using 2D Laplacian of an intracellular area as a goodness of the focus. To evaluate the performance of our developed algorithm and microscope, we auto-focus and track a freely moving paramecium. In this experimental result, the paramecium is auto-focused and kept inside the scope of the microscope during 45s. The evaluated focal error is within 5µm, while a length and a thickness of the paramecium are about 200µm and 50µm, respectively.

Obara, Takeshi; Igarashi, Yasunobu; Hashimoto, Koichi

373

Trapping cavitation bubbles with a self-focused laser beam  

NASA Astrophysics Data System (ADS)

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

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

2004-09-01

374

Trapping cavitation bubbles with a self-focused laser beam.  

PubMed

We observed that laser-induced cavitation bubbles in water can be trapped in a self-focused laser beam. Both optical imaging and acoustic detection have been utilized to confirm bubble trapping. Transverse and longitudinal trapping forces were measured to be as large as 87 and 11 pN, respectively. This result is contrary to conventional wisdom, since the mechanism of trapping in conventional optical tweezers implies that a low-index particle (a bubble being the limiting case) should be antitrapped. PMID:15460881

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

2004-09-15

375

Fully digital auto-focusing system with automatic focusing region selection and point spread function estimation  

Microsoft Academic Search

We present a fully digital auto-focusing (FDAF) system with automatic focusing region selection and a priori estimated dataset of circularly symmetric point-spread functions (PSFs). The proposed approach provides realistic, unsupervised PSF estimation by analyzing the entropy and edge information in the automatically selected focusing region. The main advantage of the proposed system is the fast and robust estimation of a

Jaehwan Jeon; Inhye Yoon; Donggyun Kim; Jinhee Lee; Joonki Paik

2010-01-01

376

Study on focusing performance of the twice reflecting laser focusing system  

Microsoft Academic Search

Laser thrusters characterized by feasible application perspective all possess the twice reflecting laser focusing system. Nonetheless, studies on its focusing performance are imperative for the research of flight route of the thruster and haven't been developed yet. Under three different focusing design modes, assisted with optical design software ZEMAX which employing Monte Carlo ray tracing, performance of twice reflecting laser

Fu Qiang Cheng; Zhi Guo Dou

2011-01-01

377

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

ERIC Educational Resources Information Center

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

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

2011-01-01

378

Laser focus accelerator by relativistic self-focusing and high electric fields in double layers of nonlinear force produced cavitons  

SciTech Connect

The laser focus accelerator with relativistic self-focusing for achieving Z-separated heavy ions of energies beyond 10 GeV was studied experimentally, in detailed numerical work and estimations on intense muon sources, heavy nuclear collisions and generation of new isotopes are on the way. The recently detected inverted double layers in the nonlinear (ponderomotive) force produced cavitons with 10/sup 9/ V/cm nearly static field can be used for electron acceleration. An upgraded present days Antares system with 20 phase-optimized steps should arrive at TeV electrons. The spontaneous high magnetic fields should produce highly directed non-Z-separated ion bunches where the E x B mechanism of Forslund and Brackbill with thermally created electric fields can be improved drastically by nonlinear force generated fields. Further studies were on acceleration by relativistic Doppler shift and by the transverse free electron laser.

Clark, P.J.; Eliezer, S.; Farley, F.J.M.; Goldsworthy, M.P.; Green, F.; Hora, H.; Kelly, J.C.; Lalousis, P.; Luther-Davies, B.; Stening, R.J.

1985-07-15

379

Laser focus accelerator by relativistic self-focusing and high electric fields in double layers of nonlinear force produced cavitons  

NASA Astrophysics Data System (ADS)

The laser focus accelerator with relativistic self-focusing for achieving Z-separated heavy ions of energies beyond 10 GeV was studied experimentally, in detailed numerical work and estimations on intense muon sources, heavy nuclear collisions and generation of new isotopes are on the way. The recently detected inverted double layers in the nonlinear (ponderomotive) force produced cavitons with 109 V/cm nearly static field can be used for electron acceleration. An upgraded present days Antares system with 20 phase-optimized steps should arrive at TeV electrons. The spontaneous high magnetic fields should produce highly directed non-Z-separated ion bunches where the E×B mechanism of Forslund and Brackbill with thermally created electric fields can be improved drastically by nonlinear force generated fields. Further studies were on acceleration by relativistic Doppler shift and by the transverse free electron laser.

Clark, P. J.; Eliezer, S.; Farley, F. J. M.; Goldsworthy, M. P.; Green, F.; Hora, H.; Kelly, J. C.; Lalousis, P.; Luther-Davies, B.; Stening, R. J.; Jin-Cheng, Wang

1985-07-01

380

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

381

Extending focus of optical microscopy and application  

NASA Astrophysics Data System (ADS)

With the development of modern science and techology, MEMS becomes an important branch. The micro operating system becomes an interested spot. During the micromanipulation process, observing the micro components by optical microscope is a crucial technology. Limited by the optical parameters, focus of the optical microscope is small. For example, focus of 10x object lens is about 10 micron. The observation of some bigger micro objects, which size is tens or hundreds of times of 10 micron, are certainly impossibe by one time imaging. Some researchers had tried to extend the focus by improving the structure of microscopy, but the results are not satisfying. The optical microscope has CCD sensor as detector. Moving the object carrier, series adjusted focus images can be given. As the distance between CCD sensor and object lens is fixed, these images are with the same amplification ration. We can use computer to analysis these images for extending the focus. Through series images to extend focus, core of this method is analyzing and processing these series images, and at last composing one image, which is clear at each vertical depth. On this image, the position of each micro object can be measured easily. Sub-pixel processing technique makes the measure precision achieve micron degree. The distance, which is recorded while adjusting the object carrier, can help to locate the vertical position of micro object, experiments show that the locating precision could up to micron degree also. Using this method avoids changing optical system hardware, and is easy achieved. Clear image can be got in the adjustable range of object carrier. The range of focus is extended. The precision can be up to micron degree on 3D direction. So the method is useful on observing and measuring of micro object, has theoretical and practical value.

Wang, Jinjiang; Liu, Wenyao; Cai, Huaiyu; Liu, Ming; Li, Rei

2003-09-01

382

Focusing Hard X Rays to Nanometer Dimensions by Adiabatically Focusing Lenses  

NASA Astrophysics Data System (ADS)

We address the question of what is the smallest spot size that hard x rays can be focused to using refractive optics. A thick refractive x-ray lens is considered, whose aperture is gradually (adiabatically) adapted to the size of the beam as it converges to the focus. These adiabatically focusing lenses are shown to have a relatively large numerical aperture, focusing hard x rays down to a lateral size of 2 nm (FWHM), well below the theoretical limit for focusing with waveguides [C. Bergemannet al., Phys. Rev. Lett.912003204801].

Schroer, C. G.; Lengeler, B.

2005-02-01

383

Localized Harmonic Motion Imaging for Focused Ultrasound Surgery Targeting  

PubMed Central

Recently, an in vivo real-time ultrasound-based monitoring technique that uses localized harmonic motion (LHM) to detect changes in tissues during focused ultrasound surgery (FUS) has been proposed to control the exposure. This technique can potentially be used as well for targeting imaging. In the present study we evaluated the potential of using LHM to detect changes in stiffness and the feasibility of using it for imaging purposes in phantoms and in vivo tumor detection. A single-element FUS transducer (80 mm focal length, 100 mm diameter, 1.485 MHz) was used for inducing a localized harmonic motion and a separate ultrasound diagnostic transducer excited by a pulser/receiver (5 kHz PRF, 5 MHz) was used to track motion. The motion was estimated using cross-correlation techniques on the acquired RF signal. Silicon phantom studies were performed in order to determine the size of inclusion that was possible to detect using this technique. Inclusions were discerned from the surroundings as a reduction on LHM amplitude and it was possible to depict inclusions as small as 4 mm. The amplitude of the induced LHM was always lower at the inclusions as compared with the one obtained at the surroundings. Ten New Zealand rabbits had VX2 tumors implanted on their thighs and LHM was induced and measured at the tumor region. Tumors (as small as 10 mm in length and 4 mm in width) were discerned from the surroundings as a reduction on LHM amplitude.

Curiel, Laura; Hynynen, Kullervo

2011-01-01

384

Fundamentals of inertial focusing in microchannels.  

PubMed

Inertial microfluidics has been attracting considerable interest in recent years due to immensely promising applications in cell biology. Despite the intense attention, the primary focus has been on development of inertial microfluidic devices with less emphasis paid to elucidation of the inertial focusing mechanics. The incomplete understanding, and sometimes confusing experimental results that indicate a different number of focusing positions in square or rectangular microchannels under similar flow conditions, have led to poor guidelines and difficulties in design of inertial microfluidic systems. In this work, we describe and experimentally validate a two-stage model inertial focusing in microchannels. Our analysis and experimental results show that not only the well-accepted shear-induced and wall-induced lift forces act on particles within flow causing equilibration near microchannel sidewalls, but the rotation-induced lift force influences the position of these equilibria. In addition, for the first time, we experimentally measure lift coefficients, which previously could only be obtained from numerical simulations. More importantly, insights offered by our two-stage model of inertial focusing are broadly applicable to cross-sectional geometries beyond rectangular. With elucidation of the equilibration mechanism, we envision better guidelines for the inertial microfluidics community, ultimately leading to improved performance and broader acceptance of the inertial microfluidic devices in a wide range of applications, from filtration to cell separations. PMID:23353899

Zhou, Jian; Papautsky, Ian

2013-03-21

385

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

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

1998-07-28

386

Focusing upgrade for sectors 11 through 19  

SciTech Connect

In order to transport high current, single bunch beams to the SLC positron source for spring 1986 testing, it will be necessary to augment the strength of available focusing in sectors 11 through 19. We have decided to replace the sector doublet type QB quadrupoles with stronger type QE magnets. In conjunction with new Vax controlled power supplies, this sector 11 through 19 doublet lattice can be run at optimal settings for beam energies of several GeV up to the full SLC energy of 32 GeV by sector 19. Installation of the temporary stronger focusing is planned for summer 1985; full SLC FODO array focusing is scheduled for the following summer. This note presents the intermediate solution for sectors 11 through 19. In addition, the sector 10 quadrupole strengths required for matching beams into the doublet array are given. 1 figure, 4 tables.

Sheppard, J.C.

1985-01-25

387

Quasi In-Focus Optical Coherence Tomography  

NASA Astrophysics Data System (ADS)

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

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

2004-02-01

388

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

389

Focusing light with a flame lens.  

PubMed

The lens is a well-understood optical component used for focusing light, but is almost exclusively made in the solid-state form and, thus, suffers from optical damage at high powers. Attempts to overcome this through the use of non-solid graded-index media for lensing, for example, heated gasses, have found limited application owing to their long focal lengths. Here we describe the first flame lens, which produces a sharp focus with very little stray light and has a fourfold increase in focal power per unit length over previous gas lenses. Such gas devices remain topical due to their inherent ability to deliver high-power laser beams: our flame lens has a 'damage' threshold that is several orders of magnitude higher than that of most conventional lenses and is immediately repaired after damage for reuse, and thus will be of use in focusing high-irradiance laser beams. PMID:23695663

Michaelis, Max M; Mafusire, Cosmas; Grobler, Jan-Hendrik; Forbes, Andrew

2013-01-01

390

NICMOS Focus Sweep at 2 FOM positions  

NASA Astrophysics Data System (ADS)

This proposal is built to run a NIC3 focus sweep from -1.5mm to -9.5mm given that the mechanical PAM default setting is -9.5mm. The FOM will then be moved +18 arcsec in Y to an offset position where another focus sweep will be executed in the same manner to determine where image quality is the best. Thermal background images will be taken at both the current FOM position, and then at offset FOM positions to check that vignetting is reduced. This proposal should be scheduled to run AS SOON AS POSSIBLE before 27-SEP-97 as part of calibration to support the NIC3 campaign. Objectives: a} Cover sufficient region of PAM focus space to ensure the optimal locations are included b} Measure vignetting and image quality at different FOM positions

Noll, Keith

1997-12-01

391

NICMOS Post-Campaign Focus Monitoring  

NASA Astrophysics Data System (ADS)

This proposal is used to determine and monitor the optimal focus and tilt settings for all three NICMOS cameras after the first NIC3 observing campaign. This proposal is built to run a NIC3 sweep every 28 days, and run NIC1 or NIC2 sweeps alternately, every 56 days, with the non-prime camera in parallel for free. This proposal will begin execution 2 weeks following the execution of the last visit of proposal 7608 {i.e. Feb 16, 1998}, and should run through the remaining cryogen lifetime. There are enough visits in this proposal {1 every 28 days} to run through Feb 1999. Objectives: a} Cover sufficient region of PAM focus space to insure the optimal locations are included b} Allow sufficient time {7-10 days} to analyze data and uplink changes when required c} reduce the number of PAM cycles by 75 cycles/month over the current NICMOS focus monitor {7608}.

Suchkov, Anatoly

1997-12-01

392

Final-focus systems in linear colliders  

NASA Astrophysics Data System (ADS)

In colliding-beam facilities, the ``final-focus system'' must demagnify the beams to attain the very small spot sizes required at the interaction points. The first final-focus system with local chromatic correction was developed for the Stanford Linear Collider, where very large demagnifications were desired. This same conceptual design has been adopted by all of the future linear collider designs as well as the Superconducting Super Collider, the Stanford and KEK B Factories, and the proposed Muon Collider. In this paper, the overall layout, physics constraints, and optimization techniques relevant to the design of final-focus systems for high-energy electron-positron linear colliders are reviewed. Finally, advanced concepts to avoid some of the limitations of these systems are discussed.

Raubenheimer, T. O.; Zimmermann, F.

2000-01-01

393

Task-focused modeling in automated agriculture  

NASA Astrophysics Data System (ADS)

Machine vision systems analyze image data to carry out automation tasks. Our interest is in machine vision systems that rely on models to achieve their designed task. When the model is interrogated from an a priori menu of questions, the model need not be complete. Instead, the machine vision system can use a partial model that contains a large amount of information in regions of interest and less information elsewhere. We propose an adaptive modeling scheme for machine vision, called task-focused modeling, which constructs a model having just sufficient detail to carry out the specified task. The model is detailed in regions of interest to the task and is less detailed elsewhere. This focusing effect saves time and reduces the computational effort expended by the machine vision system. We illustrate task-focused modeling by an example involving real-time micropropagation of plants in automated agriculture.

Vriesenga, Mark R.; Peleg, K.; Sklansky, Jack

1993-01-01

394

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

395

EDITORIAL: Focus issue on string cosmology Focus issue on string cosmology  

NASA Astrophysics Data System (ADS)

String cosmology is a grand opportunity. The field involves elements of a promising framework, string theory, that brings together gravity and quantum mechanics and attempts to unify all the interactions. Confirming the concepts of string theory is presently beyond the reach of ground-based laboratories but the heavens may provide a setting for testing the string theoretic framework. Specifically, as cosmology develops into a rigorous, data-driven scientific discipline, windows into earlier epochs and higher energies are becoming available. If string theory controlled the evolution of the very early universe it is conceivable that it might have left imprints that are still detectable today. With this possibility in mind, this focus issue of Classical and Quantum Gravity appraises recent applications of string-theoretic and string-inspired ideas to the cosmos. The contents of this issue span the following areas: (1) Inflationary scenarios within different kinds of string-theoretic sectors (C P Burgess and L McAllister; M Cicoli and F Quevedo) (2) Alternatives to conventional inflation and dark matter/energy models with novel dynamics or matter content (J-L Lehners; M Trodden and K Hinterbichler) (3) Cosmic scenarios arising from the landscape of string vacua (M Kleban; B Freivogel) (4) Dynamical mechanisms determining the number of dimensions and resolving cosmic singularities (R H Brandenberger; B Craps and O Evnin) (5) Possible subsequent consequences of an early stringy phase (E J Copeland, L Pogosian and T Vachaspati; A Mazumdar) (6) Whether an observational `window' might be accessible (D J Mulryne and J Ward). The articles in this issue also survey a number of potentially promising directions for the future.

Balasubramanian, V.; Moniz, P. R. L. V.

2011-08-01

396

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

397

Relativistic self-focusing in underdense plasma  

SciTech Connect

In the present paper, we discuss light self-focusing in underdense (nfocusing including ion dynamics will be presented in second part of the paper. In particular, we will demonstrate the formation of empty, wide channels in underdense plasma in the wake of the laser pulse. we discuss the applicability of our results to real situations and possible consequences for the ``Fast Ignitor`` project.

Feit, M.D.; Garrison, J.C.; Komashko, A.; Musher, J.L.; Rubenchik, A.M.; Turistsyn, S.K.

1997-04-24

398

Scenario development can focus the future.  

PubMed

Health care is not a focused business. No one can define it precisely. If you see your organization as being involved in health care, you'll be battered by the winds of fortune. What business are you in? People looking after people? A regional organization that focuses the physician on the patient in need? Alternative health care network? Teaching hospital? Vendor/supplier to the health care industry? If you are going to build a plan, it's important to know who you are. If you don't, you can't know wh ere you want to go. PMID:10312414

Meller, G C

399

Point-focus solar concentrator technology  

SciTech Connect

Acurex Corporation is developing state-of-the-art and advanced technology point-focus solar concentrators. The concentrators are intended for use in a modular, distributed solar thermal system capable of generating electricity or providing thermal power for small community, industrial, and isolated applications. The overall point-focus concentrator design is summarized and both state-of-the-art and advanced technology reflective panel design approaches are detailed. Test results of developmental panels are also presented. Finally, predicted thermal performance and production costs are provided.

Bedard, R.; Overly, P.; Bell, D.

1981-01-01

400

Plasma focus: Present status and potential applications  

SciTech Connect

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

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

1997-12-01

401

Automation support of patient-focused care.  

PubMed

The use of automation in hospital pharmacies is essential to support the concept of patient-focused care. Patient-focused care principles are defined, and the positive effect automation can have on supporting these principles is discussed. Automated technologies supporting drug distribution, sterile product production, prescription filling, and point of care information systems are summarized. Drug distribution technologies include distribution to and from the patient care area, distribution of medication to the patient, inventory control, controlled substance systems, and documentation of medication administration. Finally, a comprehensive automated technology system at a university teaching hospital is described. PMID:10133560

Thielke, T S

1994-04-01

402

Spatially Shifted Beam Approach to Subwavelength Focusing  

NASA Astrophysics Data System (ADS)

Although negative-refractive-index metamaterials have successfully achieved subwavelength focusing, image resolution is limited by the presence of losses. In this Letter, a metal transmission screen with subwavelength spaced slots is proposed that focuses the near-field beyond the diffraction limit and, furthermore, is easily scaled from microwave frequencies to the optical regime. An analytical model based on the superposition of shifted-beam patterns is developed that agrees very well with full-wave simulations and is corroborated by experimental results at microwave frequencies.

Markley, Loïc; Wong, Alex M. H.; Wang, Yan; Eleftheriades, George V.

2008-09-01

403

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

404

Waveguiding by axicon-focused laser beams  

SciTech Connect

We propose a method for formation of a long plasma waveguide based on axicon focusing of a radially polarized CO{sub 2} laser pulse into a uniform, low density discharge plasma. simulations demonstrate that an extended cylindrical plasma channel with a wall height {Delta}N{sub e} = 1.5 {times} 10{sup 16}cm{sup {minus}3} will be produced in a DC or RF discharge in 0.17 atm of hydrogen after axicon-focusing of a nanosecond 1-GW/cm{sup 2} CO{sub 2} laser pulse.

Pogorelsky, I.V. [Brookhaven National Lab., Upton, NY (United States); Kimura, W.D. [STI Optronics, Inc., Bellevue, WA (United States); Liu, Y. [California Univ., Los Angeles, CA (United States). Dept. of Physics

1994-06-12

405

Galaxy formation: The cosmic web in focus  

NASA Astrophysics Data System (ADS)

Detection of the trace neutral fraction of hydrogen gas that stretches between the nearby Andromeda and Triangulum galaxies has allowed resolved spectral imaging of this elusive intergalactic medium. See Letter p.224

Braun, Robert

2013-05-01

406

Focusing of HF radio-waves by ionospheric ducts  

NASA Astrophysics Data System (ADS)

This paper presents the first direct observations of HF focusing induced by natural and artificial ionospheric ducts along with a simple theoretical model. The experiments were conducted by injecting HF radio-waves using the Ionospheric Research Instrument of the High Frequency Active Auroral Research Program located in Gakona, Alaska and detecting them with instruments on the overflying French micro-satellite DEMETER. The latter observed a multiple frequency band structure, which is characteristic of a strong HF signal exceeding the detector's saturation level. Analysis of the O+ density measured by DEMETER along its orbit shows that the strong radio signal coincides with the presence of a “negative” duct in the ionosphere. “Negative” refers to the presence of a plasma density depletion with the peak depletion located near the center of the duct. Such ducts induce changes in the index of refraction leading to the focusing of HF waves in a manner equivalent to a “thick” plasma lens. Examination of the data along with a simple plasma lens model indicates the presence of focal node(s) in the vicinity of the overflying satellite. Two examples, one corresponding to focusing by a natural duct and one by an artificial one are presented.

Milikh, G. M.; Vartanyan, A.; Papadopoulos, K.; Parrot, M.

2011-08-01

407

Early Detection and Intervention in Schizophrenia: Research  

Microsoft Academic Search

The data supporting early detection and intervention are preliminary but suggestive enough to warrant further research. Overall, we need to focus greater attention on the early course of schizophrenia, including defining and describing early course, detecting cases early at onset or in the prodrome, testing whether early detection and treatment enhances treatment response and prognosis, and predicting at-risk cases early

Thomas H. McGlashan

1996-01-01

408

Capillary isoelectric focusing of haemoglobin variants in the clinical laboratory.  

PubMed

For capillary isoelectric focusing (CIEF) to be accepted in the clinical laboratory, it must be reproducible and cost effective. The advent of polyAAEE coated capillaries (Bio-Rad Laboratories, Hercules, CA, USA) has provided the means of obtaining over 100 runs per capillary, something which previously had not always been possible with coated capillaries. Using the Clinical Data Management computer program on the BioFocus 2000 Capillary Electrophoresis System (Bio-Rad Laboratories), we have used a one-step salt mobilization to achieve focusing of haemoglobin variants. Washed red cells are diluted, haemolyzed and separated in the capillary at 8 kV using 1.3% Pharmalyte ampholytes (pH 6.6-7.7/pH 6-8 2:1) in 0.40% methylcellulose. The separated haemoglobins were detected by adsorption at 280 nm. Using published values of haemoglobin variants, we investigated the use of pI markers to confirm the pI of haemoglobin variants detected. CIEF, though more expensive than capillary electrophoretic separations of haemoglobin variants, has greater resolution due to the fact that the separation of variants from pI 6.95 to 7.42 occurs over 4 min, whereas the electrophoretic separation is over 60 s. CIEF is quicker than gel IEF, and shows real-time results as the sample is being processed. The potential for CIEF in the clinical laboratory is not limited to haemoglobin variants, and the technique should become increasingly popular in the near future. PMID:10556659

Jenkins, M A; Ratnaike, S

1999-11-01

409

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

410

Project-Based Learning. Focus On  

ERIC Educational Resources Information Center

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

Clarke, Suzanne

2009-01-01

411

International Education--Focus: Soviet Union.  

ERIC Educational Resources Information Center

From March 8 to March 11, 1989, student schedules at Lake Region High School in Bridgton, Maine were replaced by Soviet Union culture and history classes. The project was called "Focus: Soviet Union," and was intended as only the first of a series of International Education Days designed to increase United States understanding of other cultures…

LaFerriere, Jake; Broyles, India

412

Focusing Surface Plasmons with a Plasmonic Lens  

Microsoft Academic Search

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

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

2005-01-01

413

Simple focus monitoring by eccentric illumination aperture  

NASA Astrophysics Data System (ADS)

Simple focus monitoring method has been successfully developed by application of a special illumination aperture, which generates oblique illumination beam. By this method, very high sensitive focus monitoring has been achieved in a current stepper. In the stop of the illumination aperture, an opening is located at eccentric position near pupil edge. Then, illumination beam obliquely incidents to mark pattern on mask. Because of this configuration of illumination beam, imaging is carried out with oblique beams on wafer. As a result, imaging becomes non-telecentric. That is, image formed by this illumination laterally shifts almost proportional to focal deviation. To measure the lateral pattern shift, box-in-box mark is formed by double exposure. Inner box is formed by the oblique illumination in the first exposure and outer box is formed by conventional low coherent illumination in the second exposure overlaying inner box by stepping of wafer. Then, relative displacement of inner box to outer box is measured by commercially available overlay measurement system. Since sine of landing angle of imaging beams is approximately NA*sigma, which is over approximately 0.50 in a current stepper, the focus sensitivity, which is defined by a ratio of lateral pattern shift per unit defocus, may become approximately 0.50. Because resolution of lateral pattern shift is approximately 2 nm in current overlay measurement, the resolution of focus sensing becomes very high of approximately several nm.

Nakao, Shuji; Maejima, Shinroku; Tamada, Naohisa; Yamashita, Shigenori; Ueno, Atsushi; Miyazaki, Junji; Tokui, Akira; Tsujita, Kouichirou; Arimoto, Ichiriou

2002-07-01

414

Task-focused Summarization of Email  

Microsoft Academic Search

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

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

2004-01-01

415

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

416

Focused Laser Beams to Assist Rock Excavation.  

National Technical Information Service (NTIS)

A study was performed to assess the feasibility of using a focused CO2 laser beam to cut the gage of a hard-rock tunnel being excavated by a continuous tunnel-boring machine. Laser rock-kerfing tests were conducted on isolated samples of granite, diabase ...

B. R. Jurewicz L. E. Greenwald C. O. Brown

1974-01-01

417

Focus on Spintronics in Reduced Dimensions  

Microsoft Academic Search

In the past ten years or so 'Spintronics' has evolved into a central part of solid state physics that addresses the intimate relation of electron charge and spin transport. To date, it is a huge field covering topics that range from applied micromagnetics to quantum computing. This invited focus issue of New Journal of Physics has become possible only by

Gerrit E W Bauer; Laurens W Molenkamp

2007-01-01

418

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

419

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

420

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

421

Microjetting from wave focusing on oscillating drops  

Microsoft Academic Search

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

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

2007-01-01

422

Performance evaluation of line-focus collectors  

SciTech Connect

An east-west aligned line-focus collector was tested under varying flow and ambient conditions. An efficiency correlation for using beam radiation was determined under steady state operation. The peak fluid temperatures observed in the receiver tubes were on the order of 120/sup 0/C.

Puri, V.M.; Okos, M.R.

1982-12-01

423

An Environmentally Focused General Chemistry Laboratory  

ERIC Educational Resources Information Center

|The environmentally focused general chemistry laboratory provides a format for teaching the concepts of the mainstream laboratory within an environmental context. The capstone integrated exercise emerged as the overwhelming favorite part of this laboratory and the experiment gave students an opportunity to do a self-directed project, using the…

Mihok, Morgan; Keiser, Joseph T.; Bortiatynski, Jacqueline M.; Mallouk, Thomas E.

2006-01-01

424

Focus. Volume 27, Number 2, Winter 2010  

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) Progress toward Improving the U.S. Poverty Measure:…

Caspar, Emma, Ed.

2010-01-01

425

Focused ion beam technologies for lithographic applications  

Microsoft Academic Search

Focused ion beam (FIB) technologies have the advantages of high resolution and maskless fabrication, which play an important role in the lithographic process for the development of advanced semiconductor devices. FIB lithography has the added advantage of obtaining a T-shaped edge profile for the fabrication of a ``mushroom gate'' of GaAs FETs by the use of different ion species. A

Tadao Kato; Akihiko Yasuoka; Kyoichiro Fujikawa

1989-01-01

426

High throughput-per-footprint inertial focusing.  

PubMed

Matching the scale of microfluidic flow systems with that of microelectronic chips for realizing monolithically integrated systems still needs to be accomplished. However, this is appealing only if such re-scaling does not compromise the fluidic throughput. This is related to the fact that the cost of microelectronic circuits primarily depends on the layout footprint, while the performance of many microfluidic systems, like flow cytometers, is measured by the throughput. The simple operation of inertial particle focusing makes it a promising technique for use in such integrated flow cytometer applications, however, microfluidic footprints demonstrated so far preclude monolithic integration. Here, the scaling limits of throughput-per-footprint (TPFP) in using inertial focusing are explored by studying the interplay between theory, the effect of channel Reynolds numbers up to 1500 on focusing, the entry length for the laminar flow to develop, and pressure resistance of the microchannels. Inertial particle focusing is demonstrated with a TPFP up to 0.3 L/(min cm(2) ) in high aspect-ratio rectangular microfluidic channels that are readily fabricated with a post-CMOS integratable process, suggesting at least a 100-fold improvement compared to previously demonstrated techniques. Not only can this be an enabling technology for realizing cost-effective monolithically integrated flow cytometry devices, but the methodology represented here can also open perspectives for miniaturization of many biomedical microfluidic applications requiring monolithic integration with microelectronics without compromising the throughput. PMID:23420756

Ciftlik, Ata Tuna; Ettori, Maxime; Gijs, Martin A M

2013-02-18

427

Focus on Basics, 2001-2002.  

ERIC Educational Resources Information Center

|This volume of newsletters focuses on connecting research and practice in adult literacy programs. Issue A of August 2001 includes: "Techniques for Teaching Beginning-Level Reading to Adults" (Ashley Hager); "Beginning ESOL Learners' Advice to Their Teachers" (MaryAnn Cunningham Florez); "The Neurobiology of Reading and Dyslexia" (Sally E.…

Garner, Barbara, Ed.

2002-01-01

428

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

429

Restructuring Education in Conyers, Georgia In Focus  

Microsoft Academic Search

In the fall of 1991, Salem High School in Conyers, Georgia opened its doors for the first time. It opened with ninth grade and will add the remaining grades in upcoming years. Salem is a pilot school with its focus on restructuring education. It is a member of the Coalition of Essential Schools (Coalition), a project based at Brown University

Christy E. Lancaster

430

Energy Distribution in the Plasma Focus  

Microsoft Academic Search

The paper studies the distribution of kinetic energy in shocked gas, work done by magnetic piston, magnetic energy and electrical energy input in a numerically optimized plasma focus using the 3-phase model of Lee (1991). Results reveal that the axial phase is made up of two distinct regions namely (i) Initial breakdown and inverse pinch region that lasts for about

M. A. Alabraba

431

Focusers of obliquely incident laser radiation  

NASA Astrophysics Data System (ADS)

Focusing obliquely incident laser radiation along a given line in space with a given intensity distribution is treated as a problem of synthesizing a mirror surface. The intricate shape of such a surface, characterized by a function z= z (u,v) in the approximation of geometrical optics, is determined from the equation phi (u,v,z) - phi O(u,v,z)=O, which expresses that the incident field and the reflected field have identical eikonals. Further calculations are facilitated by replacing continuous mirror with a more easily manufactured piecewise continuous one. The problem is solved for the simple case of a plane incident wave with a typical iconal phi O(u,v,z)= -z cos0 at a large angle to a focus mirror in the z-plane region. Mirrors constructed on the basis of the theoretical solution were tested in an experiment with a CO2 laser. A light beam with Gaussian intensity distribution was, upon incidence at a 45 deg angle, focused into a circle or into an ellipse with uniform intensity distribution. Improvements in amplitudinal masking and selective tanning technology should reduce energy losses at the surface which results in efficient laser focusing mirrors.

Goncharskiy, A. V.; Danilov, V. A.; Popov, V. V.; Prokhorov, A. M.; Sisakyan, I. N.; Sayfer, V. A.; Stepanov, V. V.

1984-08-01

432

Medically Uninsured: Special Focus on Workers.  

National Technical Information Service (NTIS)

The study focuses on three groups of workers: those without any employer-group health insurance, those with employer-group coverage, but not from their own employer, and self-employed workers. According to the study, the uninsured as a portion of the tota...

K. Swartz

1989-01-01

433

Focus Control System for Solar Thermal Propulsion.  

National Technical Information Service (NTIS)

Solar thermal propulsion (STP) uses a parabolic concentrator like a large magnifying glass to focus the sun's energy and heat a working fluid such as hydrogen to very high temperatures (3,000 K). The hydrogen is then expelled through a nozzle to produce t...

S. R. Wassom

2000-01-01

434

Asset sales and increase in focus  

Microsoft Academic Search

We find that asset sales lead to an improvement in the operating performance of the seller's remaining assets in each of the three years following the asset sale. The improvement in performance occurs primarily in firms that increase their focus; this change in operating performance is positively related to the seller's stock return at the divestiture announcement. The announcement stock

Kose John; Eli Ofek

1995-01-01

435

Welding characteristics with lasers of high focusability  

Microsoft Academic Search

The extremely good focusability of thin disk lasers provides many advantages regarding the process as well as system aspects. Using commercially achievable devices up to 6 kW, considerable improvements in welding performance are demonstrated. At very small spot diameters, it was found that, in addition to the spot diameter itself, the divergence angle of the focussed beam is deciding for

J. Weberpals; F. Dausinger; H. Hügel

2007-01-01

436

Focus on Law Studies, 1990-91.  

ERIC Educational Resources Information Center

|The fall 1990 issue includes essays that recapture some of the presentations and thinking of the 1990 American Bar Association annual conference on higher education, entitled "American Citizenship and the Constitution." The idea of community was a recurring theme of the conference, and is the focus of three essays included in the Fall 1990 issue:…

Focus on Law Studies, 1991

1991-01-01

437

Focused ion beam micromilling and articles therefrom  

DOEpatents

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

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

1998-06-30

438

Nominal grouping sessions vs focus groups  

Microsoft Academic Search

These empirical results provide new and strong support for Langford’s 1994 quantitative demonstration that the qualitative results of nominal grouping sessions (NGS) are highly reliable and valid. We also show that NGS produces responses in greater depth and breadth than many years of research have demonstrated for focus groups. Since the NGS procedure provides broad, deep, reliable and valid results

Barry E. Langford; Gerald Schoenfeld; George Izzo

2002-01-01

439

Focus: Foreign Affairs Under the Constitution  

Microsoft Academic Search

Events during the bicentennial year of the United States Constitution focused America's attention on the way in which that document both authorizes and structures an ongoing institutional struggle for dominance in the realm of foreign affairs. As the year progressed, constitutional clashes between the President and Congress spilled across the spectrum of U.S. foreign policymaking-covert operations, warmaking, arms control, foreign

Harold Hongju Koh

1988-01-01

440

Effects of Aging on Visual Attentional Focusing  

Microsoft Academic Search

Background: Visual attentional performance is affected by aging, but there are methodological barriers to the understanding of this phenomenon that are due, above all, to the concomitant deterioration of sensory or central factors such as visual acuity and information processing speed. Objective: The aim of the present study was to verify the effects of aging on visual attentional focusing by

Caterina Pesce; Laura Guidetti; Carlo Baldari; Antonio Tessitore; Laura Capranica

2005-01-01

441

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

442

Variable-focusing microlens with microfluidic chip  

Microsoft Academic Search

A new polymer microlens with variable focusing properties is designed and fabricated. The microlens consists of a thin diaphragm with 3D convex lens, chamber and microchannel, which are made of polydimethyl-siloxane (PDMS). A novel fabrication approach has been developed to cast the PDMS microlens film using a PDMS mold. The elastomeric PDMS microlens film acts as a diaphragm. The flexible

Jackie Chen; Weisong Wang; Ji Fang; Kody Varahramyan

2004-01-01

443

Dropout Prevention & Attrition Rates. IDRA Focus.  

ERIC Educational Resources Information Center

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

IDRA Newsletter, 1994

1994-01-01

444

Prenatal Cocaine Exposure and Prolonged Focus Attention  

Microsoft Academic Search

In experimental models, prenatal cocaine exposure has been found to perturb monoaminergic development of systems implicated in modulating attention. To determine whether prenatal cocaine exposure affects infant attention, we assessed visual recognition memory and focused attention during free play. We enrolled at birth 380 infants, 113 cocaine exposed, using multiple biomarkers to assess drug exposure. Behavior was videotaped and coded

Claudia A. Chiriboga; Denise Starr; Louise Kuhn; Gail A. Wasserman

2009-01-01

445

Planetary cones of focused interstellar gases  

Microsoft Academic Search

It is noted that neutral interstellar hydrogen and helium within the solar system are focused into cones by the sun and planets. Conditions are investigated under which the problem of determining the orbit of an interstellar atom in the gravitational fields of both the sun and a planet can be reduced to a two-body problem involving just the planet and

H. J. Fahr; G. Lay; P. W. Blum

1976-01-01

446

Focused ion beam micromilling and articles therefrom  

DOEpatents

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

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

1998-01-01

447

Family-focused pediatric home care.  

PubMed

Family-focused home care is a way to bring medically fragile children home to familiar surroundings and provide them with quality medical care. But the family unit has to make a number of not-so-simple adjustments for this mode of care to work. PMID:10180146

Chapman, D J

1998-05-01

448

Notes on Early Self-Focusing Papers  

NASA Astrophysics Data System (ADS)

These notes were written in August 30, 2006, about the history of two papers in Physical Review by I.W.G. Wagner, H.A. Haus, J.H. Marburger [1]; II. E.L. Dawes, J.H. Marburger [2] and the author's review paper of the year 1975 "Self-focusing: theory" [3], which is reprinted in the present book.

Marburger, John H.

449

Optimal design of focused experiments and surveys  

NASA Astrophysics Data System (ADS)

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

Curtis, Andrew

1999-10-01

450

Focusing on Staff Development and Administrative Issues.  

ERIC Educational Resources Information Center

These four conference papers from the Biennial Conference on Postsecondary Education for Persons who are Deaf or Hard of Hearing focus on staff development and administrative issues for postsecondary personnel working with students with deafness or who are hard of hearing. The first paper, "Mentorship for the Working Interpreter" (Caroline…

Kolvitz, Marcia, Ed.

451

Field Manual. Project ROME--FOCUS.  

ERIC Educational Resources Information Center

|The program described in this manual is Project ROME-FOCUS--a field-oriented, competency-based instructional program for school administrators pursuing the sixth-year degree at Valdosta State College, Georgia. It is designed to help principals work more effectively with teachers in solving school problems. The manual is intended for use by both…

Licata, Joseph W.; Ellis, Elmer C.

452

Prescribing sensate focus without proscribing intercourse  

Microsoft Academic Search

This paper challenges the need in sex therapy to routinely proscribe or forbid intercourse, viewing it as an excessive restriction for many couples, with side effects frequently causing a flight from treatment and other treatment failures. An alternative, more moderate proposal is presented which emphasizes the couple's doing sensate focus not as a prelude to orgasm or intercourse and not

Steven H. Lipsius

1987-01-01

453

Revitalize Electrical Program with Renewable Energy Focus  

ERIC Educational Resources Information Center

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

Karns, Robert J.

2012-01-01

454

Variable phaseplates for focus invariant optical systems  

Microsoft Academic Search

Depth of focus can be enhanced with cubic phaseplates located at the exit pupil of an optical system without significant loss of resolution. The enhancement factor is proportional to the strength of the phaseplate. The digital image is inversely filtered. The stronger the phaseplate is the stronger the inverse filter function must be. This causes increasing noise for high spatial

T. Hellmuth; A. Bich; R. Börret; A. Holschbach; A. Kelm

2005-01-01

455

Project-Based Learning. Focus On  

ERIC Educational Resources Information Center

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

Clarke, Suzanne

2009-01-01

456

Influence of attentional focus on skilled motor performance: Performance decrement under unfamiliar focus conditions.  

PubMed

Recent studies have demonstrated that the direction of attentional focus exerts a substantial influence on motor performance. We argue that in well-learned skills, this variable might be confounded with athletes' familiarity with focus conditions. We studied the effect of familiarity and the direction of attentional focus on performance in two experiments using 2 (familiarity)×2 (direction) within-subject designs. A significant main effect of familiarity-that is, better performance under familiar compared with unfamiliar focus conditions-confirmed the influence of familiarity on motor performance. Results are consistent with existing concepts, but lead to different consequences when applied to sport and exercise. PMID:23830490

Maurer, Heiko; Munzert, Jörn

2013-07-02

457

Field-amplified sample stacking and focusing in nanofluidic channels  

SciTech Connect

Nanofluidic technology is gaining popularity for bioanalytical applications due to advances in both nanofabrication and design. One major obstacle in the widespread adoption of such technology for bioanalytical systems is efficient detection of samples due to the inherently low analyte concentrations present in such systems. This problem is exacerbated by the push for electronic detection, which requires an even higher sensor-local sample concentration than optical detection. This paper explores one of the most common preconcentration techniques, field-amplified sample stacking, in nanofluidic systems in efforts to alleviate this obstacle. Holding the ratio of background electrolyte concentrations constant, the parameters of channel height, strength of electric field, and concentration are varied. Although in micron scale systems, these parameters have little or no effect on the final concentration enhancement achieved, nanofluidic experiments show strong dependencies on each of these parameters. Further, nanofluidic systems demonstrate an increased concentration enhancement over what is predicted and realized in microscale counterparts. Accordingly, a depth-averaged theoretical model is developed that explains these observations and furthermore predicts a novel focusing mechanism that can explain the increased concentration enhancement achieved. Specifically, when the electric double layer is sufficient in size relative to the channel height, negatively charged analyte ions are repelled from negatively charged walls, and thus prefer to inhabit the centerline of the channels. The resulting induced pressure gradients formed due to the high and low electrical conductivity fluids in the channel force the ions to move at a slower velocity in the low-conductivity region, and a faster velocity in the high-conductivity region, leading to focusing. A simple single-channel model is capable of predicting key experimental observations, while a model that incorporates the details of the fluid inlet and outlet ports allows for more detailed comparisons between model and experiment.

Sustarich, Jess M.; Pennathur, Sumita [Department of Mechanical Engineering, University of California, Santa Barbara, California 93106 (United States); Storey, Brian D. [Franklin W. Olin College of Engineering, Needham, Massachusetts 02492 (United States)