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1

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

SciTech Connect

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

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

2014-05-15

2

Contrast-Enhanced Ultrasound Imaging for the Detection of Focused Ultrasound-Induced Blood-Brain Barrier Opening  

PubMed Central

The blood-brain barrier (BBB) can be transiently and locally opened by focused ultrasound (FUS) in the presence of microbubbles (MBs). Various imaging modalities and contrast agents have been used to monitor this process. Unfortunately, direct ultrasound imaging of BBB opening with MBs as contrast agent is not feasible, due to the inability of MBs to penetrate brain parenchyma. However, FUS-induced BBB opening is accompanied by changes in blood flow and perfusion, suggesting the possibility of perfusion-based ultrasound imaging. Here we evaluated the use of MB destruction-replenishment, which was originally developed for analysis of ultrasound perfusion kinetics, for verifying and quantifying FUS-induced BBB opening. MBs were intravenously injected and the BBB was disrupted by 2 MHz FUS with burst-tone exposure at 0.5-0.7 MPa. A perfusion kinetic map was estimated by MB destruction-replenishment time-intensity curve analysis. Our results showed that the scale and distribution of FUS-induced BBB opening could be determined at high resolution by ultrasound perfusion kinetic analysis. The accuracy and sensitivity of this approach was validated by dynamic contrast-enhanced MRI. Our successful demonstration of ultrasound imaging to monitor FUS-induced BBB opening provides a new approach to assess FUS-dependent brain drug delivery, with the benefit of high temporal resolution and convenient integration with the FUS device. PMID:25161701

Fan, Ching-Hsiang; Lin, Wun-Hao; Ting, Chien-Yu; Chai, Wen-Yen; Yen, Tzu-Chen; Liu, Hao-Li; Yeh, Chih-Kuang

2014-01-01

3

Microbubble type and distribution dependence of focused ultrasound-induced blood-brain barrier opening.  

PubMed

Focused ultrasound, in the presence of microbubbles, has been used non-invasively to induce reversible blood-brain barrier (BBB) opening in both rodents and non-human primates. This study was aimed at identifying the dependence of BBB opening properties on polydisperse microbubble (all clinically approved microbubbles are polydisperse) type and distribution by using a clinically approved ultrasound contrast agent (Definity microbubbles) and in-house prepared polydisperse (IHP) microbubbles in mice. A total of 18 C57 BL/6 mice (n = 3) were used in this study, and each mouse was injected with either Definity or IHP microbubbles via the tail vein. The concentration and size distribution of activated Definity and IHP microbubbles were measured, and the microbubbles were diluted to 6 × 10(8)/mL before injection. Immediately after microbubble administration, mice were subjected to focused ultrasound with the following parameters: frequency = 1.5 MHz, pulse repetition frequency = 10 Hz, 1000 cycles, in situ peak rarefactional acoustic pressures = 0.3, 0.45 and 0.6 MPa for a sonication duration of 60 s. Contrast-enhanced magnetic resonance imaging was used to confirm BBB opening and allowed for image-based analysis. Permeability of the treated region and volume of BBB opening did not significantly differ between the two types of microbubbles (p > 0.05) at peak rarefractional acoustic pressures of 0.45 and 0.6 MPa, whereas IHP microbubbles had significantly higher permeability and opening volume (p < 0.05) at the relatively lower pressure of 0.3 MPa. The results from this study indicate that microbubble type and distribution could have significant effects on focused ultrasound-induced BBB opening at lower pressures, but less important effects at higher pressures, possibly because of the stable cavitation that governs the former. This difference may have become less significant at higher pressures, where inertial cavitation typically occurs. PMID:24239362

Wang, Shutao; Samiotaki, Gesthimani; Olumolade, Oluyemi; Feshitan, Jameel A; Konofagou, Elisa E

2014-01-01

4

Pulsed focused ultrasound-induced displacements in confined in vitro blood clots.  

PubMed

Ultrasound has been shown to potentiate the effects of tissue plasminogen activator to improve clot lysis in a range of in vitro and in vivo studies as well as in clinical trials. One possible mechanism of action is acoustic radiation force-induced clot displacements. In this study, we investigate the temporal and spatial dynamics of clot displacements and strain initiated by focused ultrasound pulses. Displacements were produced by a 1.51 MHz f-number 1 transducer over a range of acoustic powers (1-85 W) in clots constrained within an agar vessel phantom channel. Displacements were tracked during and after a 5.45 ms therapy pulse using a 20 MHz high-frequency ultrasound imaging probe. Peak thrombus displacements were found to be linear as a function of acoustic power up to 60 W before leveling off near 128 ?m for the highest transmit powers. The time to peak displacement and recovery time of blood clots was largely independent of acoustic powers with measured values near 2 ms. A linear relationship between peak axial strain and transmit power was observed, reaching a peak value of 11% at 35 W. The peak strain occurred ~0.75 mm from the focal zone for all powers investigated in both lateral and axial directions. These results indicate that substantial displacements can be induced by focused ultrasound in confined blood clots, and that the spatial and temporal displacement patterns are complex and highly dependent on exposure conditions, which has implications for future work investigating their link to clot lysis and for developing approaches to exploit these effects. PMID:22194235

Wright, Cameron C; Hynynen, Kullervo; Goertz, David E

2012-03-01

5

Feasibility study on photoacoustic guidance for high-intensity focused ultrasound-induced hemostasis  

NASA Astrophysics Data System (ADS)

The feasibility of photoacoustic imaging (PAI) application was evaluated to map punctured blood vessels thermally treated by high-intensity focused ultrasound (HIFU) for hemostasis. A single-element HIFU transducer with a central frequency of 2.0 MHz, was used to induce thermal hemostasis on the punctured arteries. The HIFU-treated lesion was imaged and localized by high-contrast PAI guidance. The results showed that complete hemostasis was achieved after treatment of the damaged blood vessels within 25 to 52 s at the acoustic intensity of 3600 W/cm2. The coagulation time for the animal artery was ˜20% longer than that of the phantom possibly due to a lower Young's modulus. The reconstructed PA images were able to distinguish the treated area from the surrounding tissue in terms of augmented signal amplitudes (up to three times). Spectroscopic studies demonstrated that the optimal imaging wavelength was found to be 700 nm in order to reconstruct high-contrast photoacoustic images on HIFU-treated lesions. The proposed PAI integrated with HIFU treatment can be a feasible application to obtain safe and rapid hemostasis for acute arterial bleeding.

Nguyen, Van Phuc; Kim, Jeehyun; Ha, Kang-lyeol; Oh, Junghwan; Kang, Hyun Wook

2014-10-01

6

Microbubble Type and Distribution Dependence of Focused Ultrasound Induced Blood Brain Barrier Opening  

PubMed Central

Focused Ultrasound (FUS) in the presence of microbubbles has been used to non-invasively induce reversible blood brain barrier (BBB) opening in both rodents and non-human primates. This study aims at identifying the dependence of the BBB opening properties on the polydisperse microbubble (since all clinically approved microbubbles are polydisperse) type and distribution by using clinically approved UCA (Definity®) and in-house made polydisperse microbubbles (IHP) in mice. A total of 18 C57BL/6 mice (n = 3) were used in this study, and each mouse received either Definity® or IHP microbubbles via tail vein injection. The concentration and size distribution of both the activated Definity® and IHP microbubbles were measured and diluted to 6×108/ml prior to injection. Immediately after the microbubble administration, FUS sonications were carried out with the following parameters: frequency of 1.5 MHz, pulse repetition frequency of 10 Hz, 1000 cycles, in situ peak rarefactional acoustic pressures of 0.3 MPa, 0.45 MPa, and 0.6 MPa for a sonication duration of 60 s. Contrast-enhanced magnetic resonance imaging (MRI) was used to confirm the BBB opening and allowed for image-based analysis. The permeability of the treated region and volumes of BBB opening using the two types of microbubbles did not show significant difference (P > 0.05) for PRPs of 0.45 MPa and 0.6 MPa, while IHP microbubbles showed significantly higher permeability and volume of opening (P < 0.05) at the relatively lower pressure of 0.3 MPa. The results from this study indicate that the microbubble type and distribution could have significant effects on the FUS-induced BBB opening at lower, but less important at higher, pressure levels, possibly due to the stable cavitation that governs the former. This difference may have become less significant at higher FUS pressure levels where inertial cavitation typically occurs. PMID:24239362

Wang, Shutao; Samiotaki, Gesthimani; Olumolade, Oluyemi; Feshitan, Jameel A.; Konofagou, Elisa E.

2014-01-01

7

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

8

Effects of acoustic parameters and ultrasound contrast agent dose on focused-ultrasound induced blood-brain barrier disruption  

PubMed Central

Previously, it was shown that low-intensity focused ultrasound pulses applied along with an ultrasound contrast agent results in temporary blood-brain barrier (BBB) disruption. This effect could be used for targeted drug delivery in the central nervous system. This study examined the effects of burst length, pulse repetition frequency (PRF), and ultrasound contrast agent dose on the resulting BBB disruption. One hundred non-overlapping brain locations were sonicated through a craniotomy in experiments in rabbits (ultrasound frequency: 0.69 MHz, burst: 0.1, 1, 10 ms, PRF: 0.5, 1, 2, 5 Hz, duration: 20s, peak negative pressure amplitude: 0.1–1.5 MPa, Optison dosage 50, 100, 250 µl/kg). For each sonication, BBB disruption was evaluated using contrast-enhanced magnetic resonance imaging. The BBB disruption threshold (the pressure amplitude yielding a 50% probability for BBB disruption) was determined using probit regression for the three burst lengths tested. Tissue effects were examined in light microscopy for representative locations with similar amounts of contrast enhancement from each group. While changing the PRF or the Optison dosage did not result in a significant difference in the magnitude of the BBB disruption (P>0.05), reducing the burst length resulted in significantly less contrast enhancement (P<0.01). The BBB disruption thresholds were estimated to be 0.69, 0.47, and 0.36 MPa for 0.1, 1, and 10 ms bursts respectively. No difference was detected in histology between any experimental group. This data suggests that over the range of parameters tested, BBB disruption is not affected by PRF or ultrasound contrast agent dose. However, both the BBB disruption magnitude and its threshold depend on the burst length. PMID:18294757

McDannold, Nathan; Vykhodtseva, Natalia; Hynynen, Kullervo

2008-01-01

9

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

PubMed Central

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

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

2013-01-01

10

Nakagami imaging for detecting thermal lesions induced by high-intensity focused ultrasound in tissue.  

PubMed

High-intensity focused ultrasound induces focalized tissue coagulation by increasing the tissue temperature in a tight focal region. Several methods have been proposed to monitor high-intensity focused ultrasound-induced thermal lesions. Currently, ultrasound imaging techniques that are clinically used for monitoring high-intensity focused ultrasound treatment are standard pulse-echo B-mode ultrasound imaging, ultrasound temperature estimation, and elastography-based methods. On the contrary, the efficacy of two-dimensional Nakagami parametric imaging based on the distribution of the ultrasound backscattered signals to quantify properties of soft tissue has recently been evaluated. In this study, ultrasound radio frequency echo signals from ex vivo tissue samples were acquired before and after high-intensity focused ultrasound exposures and then their Nakagami parameter and scaling parameter of Nakagami distribution were estimated. These parameters were used to detect high-intensity focused ultrasound-induced thermal lesions. Also, the effects of changing the acoustic power of the high-intensity focused ultrasound transducer on the Nakagami parameters were studied. The results obtained suggest that the Nakagami distribution's scaling and Nakagami parameters can effectively be used to detect high-intensity focused ultrasound-induced thermal lesions in tissue ex vivo. These parameters can also be used to understand the degree of change in tissue caused by high-intensity focused ultrasound exposures, which could be interpreted as a measure of degree of variability in scatterer concentration in various parts of the high-intensity focused ultrasound lesion. PMID:24264647

Rangraz, Parisa; Behnam, Hamid; Tavakkoli, Jahan

2014-01-01

11

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

Microsoft Academic Search

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

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

2010-01-01

12

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

PubMed

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

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

2010-01-01

13

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

14

Quantitative observation of focused-ultrasound-induced vascular leakage and deformation via fluorescein angiography and optical coherence tomography.  

PubMed

Focused ultrasound (FUS) is a recently discovered noninvasive technique for local and temporal enhancement of vascular permeability, which facilitates drug delivery from the vessels into the surrounding tissue. However, exposure to FUS at a high intensity may cause permanent damage. To investigate the effects of the FUS treatment on blood vessels, we propose to use fluorescein angiography (FA) and optical coherence tomography (OCT) for real-time observation of the diffusion of fluorescence dye from blood vessels and to evaluate the morphological changes of the vessels in vivo. With time-resolved FA imaging, the relationship between the exposed power and the improved permeability of the vessels can be assessed according to the enhancement of the fluorescent intensity due to the dye leakage. Furthermore, the variation of the time-resolved fluorescent intensities can be used to identify the occurrence of dye leakage. In contrast, OCT can be implemented for the reconstruction of tissue microstructures. To quantitatively evaluate the morphological changes of the vessels after the FUS exposure with OCT, a new algorithm was proposed to estimate the vessel area based on the comparison of backscattering properties resulting from the tissue and vascular structures. Results showed that the vessel area increased as the exposed power increased, and the area became significantly larger at a higher FUS exposure power of 10 W. In conclusion, integrated FA and OCT observation can be potentially effective for monitoring the outcome and investigating the effects of FUS treatment. PMID:23812607

Tsai, Meng-Tsan; Lee, Cheng-Kuang; Lin, Kung-Min; Lin, Yu-Xiang; Lin, Tzu-Han; Chang, Ting-Chia; Lee, Jiann-Der; Liu, Hao-Li

2013-10-01

15

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

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

16

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

17

Ultrasound-inducible fluorescent particles for internal tattooing  

Microsoft Academic Search

Our objective is to selectively and non-invasively deposits markers under image guidance for internal tattooing. This study describes the production of ultrasound-inducible particles carrying large payloads of fluorescent markers and the in vivo proof of concept of their remote deposit via focused ultrasound. The particles are double emulsions produced in a microfluidic system, consisting of aqueous fluorescein in perfluorocarbon in

O. Couture; N. Pannacci; A. Babataheri; P. Tabeling; M. Fink; M. Tanter; V. Servois

2009-01-01

18

Multiple Low-Pressure Sonications to Improve Safety of Focused-Ultrasound Induced Blood-Brain Barrier Disruption: In a 1.5MHz Transducer Setup  

Microsoft Academic Search

Burst-mode driven high intensity focused ultrasound (HIFU) with the presence of ultrasound micro bubbles has been proven to\\u000a be capable of locally and reversibly increasing the permeability of blood-brain barrier (BBB). However, the use of excessive\\u000a acoustic pressure usually accompanied with intracerebral hemorrhage, which is considered a deterred side effect, especially\\u000a when in applications such as drug delivery. The purpose

P. H. Hsu; J. J. Wang; K. J. Lin; J. C. Chen; H. L. Liu

19

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

20

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

PubMed

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

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

2014-07-01

21

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

NASA Astrophysics Data System (ADS)

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

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

2006-08-01

22

Pharmacodynamic and Therapeutic Investigation of Focused Ultrasound-Induced Blood-Brain Barrier Opening for Enhanced Temozolomide Delivery in Glioma Treatment  

PubMed Central

Focused ultrasound (FUS) exposure with the presence of microbubbles has been shown to transiently open the blood-brain barrier (BBB), and thus has potential to enhance the delivery of various kinds of therapeutic agents into brain tumors. The purpose of this study was to assess the preclinical therapeutic efficacy of FUS-BBB opening for enhanced temozolomide (TMZ) delivery in glioma treatment. FUS exposure with microbubbles was delivered to open the BBB of nude mice that were either normal or implanted with U87 human glioma cells. Different TMZ dose regimens were tested, ranging from 2.5 to 25 mg/kg. Plasma and brain samples were obtained at different time-points ranging from 0.5 to 4 hours, and the TMZ concentration within samples was quantitated via a developed LC-MS/MS procedure. Tumor progression was followed with T2-MRI, and animal survival and brain tissue histology were conducted. Results demonstrated that FUS-BBB opening caused the local TMZ accumulation in the brain to increase from 6.98 to 19 ng/mg. TMZ degradation time in the tumor core was found to increase from 1.02 to 1.56 hours. Improved tumor progression and animal survival were found at different TMZ doses (up to 15% and 30%, respectively). In conclusion, this study provides preclinical evidence that FUS-BBB opening increases the local concentration of TMZ to improve the control of tumor progression and animal survival, suggesting the potential for clinical application to improve current brain tumor treatment. PMID:25490097

Liu, Hao-Li; Huang, Chiung-Yin; Chen, Ju-Yu; Wang, Hay-Yan Jack; Chen, Pin-Yuan; Wei, Kuo-Chen

2014-01-01

23

The role of acoustic cavitation in enhanced ultrasound- induced heating in a tissue-mimicking phantom  

Microsoft Academic Search

A complete understanding of high-intensity focused ultrasound-induced temperature changes in tissue requires insight into all potential mechanisms for heat deposition. Applications of therapeutic ultrasound often utilize acoustic pressures capable of producing cavitation activity. Recognizing the ability of bubbles to transfer acoustic energy into heat generation, a study of the role bubbles play in tissue hyperthermia becomes necessary. These bubbles are

Patrick Lee Edson

2001-01-01

24

Magnetoresistive Flux Focusing Eddy Current Flaw Detection  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

25

Magnetoresistive flux focusing eddy current flaw detection  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

26

Ultrasound-Induced Disruption of Amphiphilic Block Copolymer Micelles  

E-print Network

Ultrasound-Induced Disruption of Amphiphilic Block Copolymer Micelles Juan Xuan, Maxime Pelletier (BCP) micelles for controlled delivery applications, to date the use of ultrasound[1] as an external stimulus has been less explored than the use of pH,[2] temperature,[3] or even light.[4] And yet ultrasound

Zhao, Yue

27

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

PubMed

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

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

2012-06-01

28

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

PubMed Central

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

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

2012-01-01

29

Multifocus image fusion scheme using focused region detection and multiresolution  

NASA Astrophysics Data System (ADS)

To solve the fusion problem of the multifocus images of the same scene, a novel algorithm based on focused region detection and multiresolution is proposed. In order to integrate the advantages of spatial domain-based fusion methods and transformed domain-based fusion methods, we use a technique of focused region detection and a new fusion method of multiscale transform (MST) to guide pixel combination. Firstly, the initial fused image is acquired with a novel multiresolution image fusion method. The pixels of the original images, which are similar to the corresponding initial fused image pixels, are considered to be located in the sharply focused regions. By this method, the initial focused regions can be determined, and the techniques of morphological opening and closing are employed for post-processing. Then the pixels within the focused regions in each source image are selected as the pixels of the fused image; meanwhile, the initial fused image pixels which are located at the focused border regions are retained as the pixels of the final fused image. The fused image is then obtained. The experimental results show that the proposed fusion approach is effective and performs better in fusing multi-focus images than some current methods.

Chai, Yi; Li, Huafeng; Li, Zhaofei

2011-09-01

30

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

31

Attention focusing and anomaly detection in systems monitoring  

NASA Technical Reports Server (NTRS)

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

Doyle, Richard J.

1994-01-01

32

The origin of ultrasound-induced friction reduction in microscopic mechanical contacts.  

PubMed

We present a study of the origin of ultrasound-induced friction reduction in microscopic mechanical contacts. The effect of friction reduction caused by Rayleigh-type surface acoustic waves (SAWs) is demonstrated for propagating and two-dimensional, standing wave fields using lateral force microscopy (LFM). It is shown that with increasing wave amplitude, friction is completely suppressed. To detect and distinguish between the effect of lateral and vertical surface oscillation components on the cantilever movement, we employed multimode scanning acoustic force microscopy (SAFM). We found that the friction reduction effect is only due to the vertical oscillation component. Because this effect does not appear for purely in-plane polarized Love waves, we concluded that the mechanical diode effect is most probably responsible for the SAW-induced lubrication. This explanation is also supported by vertical and longitudinal SAFM measurements, which show that, in areas where friction is completely suppressed, low frequency vertical cantilever oscillations can still be observed, whereas lateral or torsional oscillations are no longer excited. PMID:12322886

Hesjedal, Thorsten; Behme, Gerd

2002-03-01

33

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

PubMed

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

Gottwald, Georg A; Skokos, Charalampos

2014-06-01

34

Automated focusing in bright-field microscopy for tuberculosis detection  

PubMed Central

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

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

2010-01-01

35

Rotating flux-focusing eddy current probe for flaw detection  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

36

Ultrasound-induced lung hemorrhage: Role of acoustic boundary conditions at the pleural surface  

E-print Network

Ultrasound-induced lung hemorrhage: Role of acoustic boundary conditions at the pleural surface intercostal tissue and lung was evaluated as a possible explanation for the enhanced lung damage the volume of air inspired and expired. The acoustic impedance difference between intercostal tissue and lung

Illinois at Urbana-Champaign, University of

37

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

E-print Network

, therefore, do no penetrate the BBB. As a result, only 5% of the current drugs treat Central Nervous System]. Many of the current brain drug delivery systems being developed open the BBB either locally, transiently, and locally. These studies were demonstrated in rabbits [3, 4], mice [5-8], and rats [9

Konofagou, Elisa E.

38

Pulsed Focused Ultrasound-Induced Displacements in Confined In Vitro Blood Clots  

Microsoft Academic Search

Ultrasound has been shown to potentiate the effects of tissue plasminogen activator to improve clot lysis in a range of in vitro and in vivo studies as well as in clinical trials. One possible mechanism of action is acoustic radiation force-induced clot displacements. In this study, we investigate the temporal and spatial dynamics of clot displacements and strain initiated by

Cameron C. Wright; Kullervo Hynynen; David E. Goertz

2012-01-01

39

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

PubMed Central

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

Tsuda, Hiroshi; Kumakura, Kenji; Ogihara, Shinji

2010-01-01

40

Ultrasound-induced cellular uptake of plasmonic gold nanorods  

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

41

Focus  

NSDL National Science Digital Library

The Institute for Research on Poverty at University of Wisconsin-Madison held a welfare reform conference in March 1997. Both the summary and full proceedings of the conference are available. Note that the summary is available in Focus. The Personal Responsibility and Work Opportunity Reconciliation Act of 1996 was passed on August 22, 1996. The Act "changed the nation's welfare system into one that requires work in exchange for time-limited assistance."

42

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

E-print Network

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

Ling, Haibin

43

Mechanism of the protective effects of long chain n-alkyl glucopyranosides against ultrasound-induced cytolysis of HL-60 cells  

PubMed Central

Recently it has been shown that long chain (C5 to C8) n-alkyl glucopyranosides completely inhibit ultrasound-induced cytolysis [1]. This protective effect has possible applications in HIFU (high intensity focused ultrasound) for tumor treatment, and in ultrasound assisted drug delivery and gene therapy. n-Alkyl glucopyranosides with hexyl (5mM), heptyl (3mM), octyl (2mM) n-alkyl chains protected 100% of HL-60 cells in-vitro from 1.057 MHz ultrasound induced cytolysis under a range of conditions that resulted in 35% to 100% cytolysis in the absence of glucopyranosides. However the hydrophilic methyl-?-D-glucopyranoside did not protect cells. The surface active n-alkyl glucopyranosides accumulate at the gas-liquid interface of cavitation bubbles. The OH radicals and H atoms formed in collapsing cavitation bubbles react by H-atom abstraction from either the n-alkyl chain or the glucose moiety of the n-alkyl glucopyranosides. Owing to the high concentration of the long chain surfactants at the gas-liquid interface of cavitation bubbles, the initially formed carbon radicals on the alkyl chains are transferred to the glucose moieties to yield radicals which react with oxygen leading to the formation of hydrogen peroxide. In this work we find that the sonochemically produced hydrogen peroxide yields from oxygen-saturated solutions of long chain (hexyl, octyl) n-alkyl glucopyranosides at 614 kHz and 1.057 MHz ultrasound increase with increasing n-alkyl glucopyranoside concentration but are independent of concentration for methyl-?-D-glucopyranoside. These results are consistent with the previously proposed mechanism of sonoprotection [1]. This sequence of events prevents sonodynamic cell killing by initiation of lipid peroxidation chain reactions in cellular membranes by peroxyl and/or alkoxyl radicals [2]. PMID:17224298

Cheng, Jason Y.; Riesz, Peter

2007-01-01

44

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

PubMed Central

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

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

2013-01-01

45

Macromolecular crowding conditions enhance glycation and oxidation of whey proteins in ultrasound-induced Maillard reaction.  

PubMed

High intensity ultrasound (HIUS) can promote Maillard reaction (MR). Macromolecular crowding conditions accelerate reactions and stabilise protein structure. The aim of this study was to investigate if combined application of ultrasound and macromolecular crowding can improve efficiency of MR. The presence of crowding agent (polyethylene glycol) significantly increased ultrasound-induced whey protein (WP) glycation by arabinose. An increase in glycation efficiency results only in slight change of WP structure. Macromolecular crowding intensifies oxidative modifications of WP, as well as formation of amyloid-like structures by enhancement of MR. Solubility at different pH, thermal stability and antioxidative capacity of glycated WP were increased, especially in the presence of crowding agent, compared to sonicated nonglycated proteins. The application of HIUS under crowding conditions can be a new approach for enhancement of reactions in general, enabling short processing time and mild conditions, while preserving protein structure and minimising protein aggregation. PMID:25660883

Perusko, Marija; Al-Hanish, Ayah; Cirkovic Velickovic, Tanja; Stanic-Vucinic, Dragana

2015-06-15

46

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

PubMed

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

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

2015-04-01

47

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

Microsoft Academic Search

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

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

1988-01-01

48

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

PubMed Central

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

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

2013-01-01

49

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

50

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

51

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

E-print Network

IMAGE MATCHING ERROR DETECTION WITH FOCUS ON MATCHING OF SAR AND OPTICAL IMAGES Soukal Peter Radar) images of various spatial resolutions and naturally different bands. The aims of such matching could be various, like image co-registration, needed for various applications, where a combination

Schindler, Konrad

52

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

NASA Technical Reports Server (NTRS)

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

Doyle, R.

1994-01-01

53

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

NASA Technical Reports Server (NTRS)

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

Bernacki, Bruce E.; Mansuripur, M.

1992-01-01

54

Effect of gravitational focusing on annual modulation in dark-matter direct-detection experiments.  

PubMed

The scattering rate in dark-matter direct-detection experiments should modulate annually due to Earth's orbit around the Sun. The rate is typically thought to be extremized around June 1, when the relative velocity of Earth with respect to the dark-matter wind is maximal. We point out that gravitational focusing can alter this modulation phase. Unbound dark-matter particles are focused by the Sun's gravitational potential, affecting their phase-space density in the lab frame. Gravitational focusing can result in a significant overall shift in the annual-modulation phase, which is most relevant for dark matter with low scattering speeds. The induced phase shift for light O(10)??GeV dark matter may also be significant, depending on the threshold energy of the experiment. PMID:24483881

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

2014-01-10

55

Flexible Integration of Both High Imaging Resolution and High Power Arrays for Ultrasound-Induced Thermal Strain Imaging (US-TSI)  

PubMed Central

Ultrasound-induced thermal strain imaging (US-TSI) for carotid artery plaque detection requires both high imaging resolution (<100 ?m) and sufficient US induced heating to elevate the tissue temperature (~1-3°C within 1-3 cardiac cycles) in order to produce a noticeable change in sound speed in the targeted tissues. Since the optimization of both imaging and heating in a monolithic array design is particularly expensive and inflexible, a new integrated approach is presented that utilizes independent ultrasound arrays to meet the requirements for this particular application. This work demonstrates a new approach in dual-array construction. A 3D printed manifold was built to support both a high resolution 20 MHz commercial imaging array and 6 custom heating elements operating in the 3.5-4 MHz range. For the application of US-TSI on carotid plaque characterization, the tissue target site is 20 to 30 mm deep, with a typical target volume of 2 mm (elevation) × 8 mm (azimuthal) × 5 mm (depth). The custom heating array performance was fully characterized for two design variants (flat and spherical apertures), and can easily deliver 30 W of total acoustic power to produce intensities greater than 15 W/cm2 in tissue target region. PMID:24297029

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

2013-01-01

56

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

PubMed

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

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

2013-12-01

57

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

E-print Network

Alzheimer's [1], Huntington's [2] and Parkinson's [3] diseases as well as brain cancers [4,5]. Various therapeutic agents, including antibodies [6], neural stem cells [7], siRNA [2], chemotherapeutic molecules [8 of therapeutic agents in the brain for the treatment of central nervous system diseases. Currently, microbubbles

Konofagou, Elisa E.

58

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

59

Isoelectric focusing and ELISA for detecting adulteration of donkey milk with cow milk.  

PubMed

Donkey milk has been recently revalued intensely due to its nutritional properties. Moreover, donkey milk has been proposed as an effective alternative food for some infants with cow milk allergy. Two fast analytical methods were proposed to detect the fraudulent practice of blending cow milk to donkey milk. Detection of cow ?s1-casein bands along the profiles of experimental donkey-cow milk mixtures analyzed by isoelectric focusing was adequate to estimate cow milk used as adulterant of donkey milk starting from 5% (v/v). An ELISA-based method using the antipeptide antibodies raised against the 1-28 sequence stretch of cow ?-casein was also developed for an accurate definition of composition of donkey-cow milk mixtures. The presence of cow milk at levels as low as 0.5% (v/v) was detected in donkey-cow milk mixtures prepared at laboratory scale and assayed by ELISA. PMID:24892189

Pizzano, Rosa; Salimei, Elisabetta

2014-06-25

60

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

61

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

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

62

Optimization of micro-HPLC peak focusing for the detection and quantification of low hepcidin concentrations.  

PubMed

Micro-high-performance liquid chromatography is a miniaturized, economic and ecological chromatographic system allowing the use of reduced size chromatographic columns. Coupled with electrospray ionization tandem mass spectrometry, this technique can be used to detect and quantify low concentrations of peptides. In this study, hepcidin was used as the model compound and analysed using octadecylsilica stationary phase by means of a gradient elution mode at a flow rate of 4??L/min. Several parameters were studied to optimize peak focusing. Using the methodology of experimental design, the mobile-phase gradient conditions and the sample composition were optimized in order to maximize the sensitivity and minimize retention time. Stability of the target peptide in solution was also demonstrated. PMID:21721124

Mansion, François; Chiap, Patrice; Houbart, Virginie; Crommen, Jacques; Servais, Anne-Catherine; Fillet, Marianne

2011-08-01

63

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

64

Detecting electrical and hydraulic heterogeneities using seismic focusing and seismoelectric conversions  

NASA Astrophysics Data System (ADS)

When a seismic wave propagates through a porous material and encounters a discontinuity in hydraulic or electrical properties, part of its energy is converted into an electromagnetic signal. Recording and interpreting this signal can be used to infer properties of the subsurface such as electrical conductivity, porosity, permeability, and saturation. However, a major issue of this method is that the amplitude of the converted electromagnetic signal is usually quite low and difficult to measure directly in the field. Sava & Revil recently proposed a seismic focusing technique (which will be referred to as "beamforming"), where multiple seismic sources located around the area of interest (usually placed in boreholes) are used to concentrate seismic energy at a desired location and time. If the focus point is located at a heterogeneity, a seismoelectric conversion will take place with a much greater amplitude than if a unique source had been used, making the converted signal easier to detect. So far, this new technique has only been tested on a simple case study and further investigations are needed to assess its strengths, weaknesses, and future potential applications. In this thesis, I develop a finite-element numerical model for the beamforming technique (coupled with seismoelectric conversions) in the frequency domain. I then perform a set of important numerical tests to assess the properties of the converted electromagnetic signals generated by the beamforming technique. Finally, the numerical beamforming model is successfully applied to track the location of a water saturation front inside an oil reservoir undergoing a water flooding process.

Barnier, Guillaume

65

Application of capillary isoelectric focusing with absorption imaging detection to the analysis of proteins.  

PubMed

A capillary isoelectric focusing instrument with an on-line optical absorption imaging detector was used to analyse protein samples. The separation column was a 4 cm x 100 microns I.D. capillary. The light source of the imaging detector was a argon ion laser. The light beam from the laser was focused into the capillary by a cylindrical lens. An 1024-pixel charge-coupled device (CCD) measured intensity of light beam passing through the capillary. The optical alignment of the detector was optimized to eliminate interference produced by the refractive index gradient created by sample zones inside the capillary. The signal-to-noise ratio of the detector was enhanced by averaging 30 scans of the CCD every 3 s. The on-line imaging detector allows simultaneous separation and detection so that the analysis time for a sample is only 2-4 min. Several protein samples were analyzed by the instrument, including human hemoglobin variants, cytochrome c, myoglobin and transferrin. PMID:7952097

Wu, J; Pawliszyn, J

1994-07-15

66

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

67

Determination of cabergoline by electrospray ionization tandem mass spectrometry: picogram detection via column focusing sample introduction.  

PubMed

An electrospray ionization tandem mass spectrometric method was developed for low-picogram detection of an ergot alkaloid, cabergoline, in coyote plasma extracts. Cabergoline is under investigation as an abortifacient in canid species. Central to the successful development of this method was the ability to introduce relatively large sample volumes into the mass spectrometer. This was achieved by focusing the analyte on a conventional high-performance liquid chromatography guard column prior to elution into the spectrometer. Volumes up to at least 900 microL could be injected onto the guard column using a 100% aqueous mobile phase. Cabergoline retained on the column was eluted as a discreet band into the mass spectrometer by the rapid addition of methanol (30%) to the mobile phase. As compared to flow injection sample introduction, the ability to inject larger sample volumes led to a greatly lowered detection limit. Using this technique and a modification of a previously reported extraction procedure, cabergoline could be determined in coyote plasma at concentrations as low as 9 pg of cabergoline/mL of plasma. PMID:11681474

Kimball, B A; DeLiberto, T J; Johnston, J J

2001-10-15

68

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

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

69

Ultrasound-induced hyperthermia for the spatio-temporal control of gene expression in bone repair  

NASA Astrophysics Data System (ADS)

Spatial and temporal control over the expression of growth/differentiation factors is of great interest for regeneration of bone, but technologies capable of providing tight and active control over gene expression remain elusive. We propose the use of focused ultrasound for the targeted activation of heat shock-sensitive expression systems in engineered bone. We report in vitro results with cells that express firefly luciferase (fLuc) under the control of a heat shock protein promoter. Cells were embedded in fibrin scaffolds and exposed to focused ultrasound, using a custom 3.3MHz transducer (focal length 4", f-number 1.33", focal dimension 1.2mm lateral FWHM) in CW mode for 2-20 minutes at intensities ISPTA=120-440 W/cm2. The kinetics of ultrasound-mediated activation of the cells was compared with that of strictly thermal activation. Bioluminescence imaging revealed fLuc expression in an area ?2.5mm in diameter at the position of the ultrasound focus, and the diameter and intensity of the signal increased with the amplitude of the acoustic energy. We also found that ultrasound activated fLuc expression with substantially shorter exposures than thermal activation. Our results demonstrate the potential for focused ultrasound to selectively activate the expression of a gene of interest in an engineered tissue and suggest that focused ultrasound activates the heat shock pathway by a combination of thermal and non-thermal mechanisms.

Wilson, Christopher; Padilla, Frédéric; Zhang, Man; Vilaboa, Nuria; Kripfgans, Oliver; Fowlkes, Brian; Franceschi, Renny

2012-10-01

70

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

E-print Network

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

Paris-Sud XI, Université de

71

This paper focuses on solving the failure detection and isolation (FDI) problem by developing a model-based  

E-print Network

respects: (1) a novel transformation matrix computation is presented that enhances the isolation properties is exposed. In section 4 a novel calculation of the transformation matrix is proposed to improve isolationAbstract This paper focuses on solving the failure detection and isolation (FDI) problem

Taylor, James H.

72

Skull surface detection algorithm to optimize time reversal focusing through a human skull  

Microsoft Academic Search

Ultrasound has two main medical applications: imaging and therapy. Echographic imaging is particularly suited for soft tissues, such as liver, kidney or fetus. Treatment trials mainly concern liver, prostate, and bladder. In order to develop clinical applications dedicated to the human brain, one has to precisely focus ultrasound through the skull. The human skull induces both phase and amplitude aberrations.

Jean-Francois Aubry; Didier Cassereau; Mickael Tanter; Thomas Pellegrini; Mathias Fink

2002-01-01

73

Diagnostic Ultrasound Induced Inertial Cavitation to Non-Invasively Restore Coronary and Microvascular Flow in Acute Myocardial Infarction  

PubMed Central

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.

2013-01-01

74

Alpha2-HS-Glycoprotein Polymorphism Detected in Human Urine by Isoelectric Focusing and Immunoblotting  

Microsoft Academic Search

Polymorphism of ?2-HS-glycoprotein (AHSG) was revealed in human urine by isoelectric focusing and immunoblotting on polyacrylamide gels. More than 200 urine samples were examined in this manner and correct AHSG typing of the urine samples was achieved, in comparison with the results of direct grouping for plasma. Three phenotypes, AHSG 1,2–1 and 2, were observed and found to be determined

K. Kishi; T. Yasuda; Y. Ikehara

1988-01-01

75

Modelling ultrasound-induced mild hyperthermia of hyperplasia in vascular grafts  

PubMed Central

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

2011-01-01

76

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

NASA Astrophysics Data System (ADS)

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

Query, Michael Earl

77

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

PubMed

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

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

2014-01-01

78

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

PubMed Central

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

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

2014-01-01

79

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. PMID:19693376

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

2007-01-01

80

PLLA Nanofibrous Paper-Based Plasmonic Substrate with Tailored Hydrophilicity for Focusing SERS Detection.  

PubMed

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

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

2015-03-11

81

Detection of clandestine tunnels in complex environments using a mobile focused-source electromagnetic data measurement and processing unit  

NASA Astrophysics Data System (ADS)

We have developed a new technology for detecting underground tunnels - the Tunnel Detection Focused-Source Electromagnetic (TD-FSEM) method. It uses four horizontal electric dipole transmitters and a five-electrode grounded quadrupole receiver to measure the transient EM field. Such a setup directs the current under the receiver vertically, increasing the sensitivity of the measurement system to a relatively narrow column of subsurface media directly below the receiver. Our previously published feasibility modeling results allowed us to prove the concept by showing that the method provides data sufficient for reliable detection of clandestine tunnels embedded in a homogeneous subsurface. In this paper, we present a 3D EM modeling results showing that our method can be efficiently used in presence of near-surface conductive or resistive obstructions. We present comparisons of GPR, conventional dipole-dipole Controlled-Source EM (CSEM), and our TD-FSEM methods and show that the TD-FSEM, unlike conventional GPR and CSEM, allows for removal of unwanted shallow/near-surface masking effects. The TD-FSEM acquisition and processing unit can be mounted on a vehicle performing large-scale regional and local operations.

Davydycheva, Sofia; Frenkel, Michael

2012-06-01

82

Genetic analysis of dobrava-belgrade virus from Western serbia - a newly detected focus in the balkan peninsula.  

PubMed

Dobrava-Belgrade virus (DOBV) is a hantavirus species that causes the most severe form of haemorrhagic fever with renal syndrome (HFRS) in Europe. DOBV has been detected in three Apodemus rodents: A. flavicollis, A. agrarius and A. ponticus. These emerging viruses appear throughout the Balkan Peninsula including Serbia as its central part. In this study, we examined the seroprevalence, molecular epidemiology and phylogenetics of DOBV from A. flavicollis captured at six Serbian localities. Furthermore, we applied microsatellite typing of host animal genome to analyse the role of host kinship in DOBV animal transmission. The overall IgG seropositivity rate over 3 years (2008-2010) was 11.9% (22/185). All seropositive samples were subjected to RT-PCR and DNA sequencing for S and L genome segments (pos. 291-1079 nt and 2999-3316 nt, respectively). DOBV was genetically detected in three samples from mountain Tara in western Serbia, a newly detected DOBV focus in the Balkans. No sequence data from human cases from Serbia are available for the studied period. However, collected DOBV isolates in this work phylogenetically clustered together with isolates from Serbian human cases dating from 2002, with 1.9% nucleotide divergence. We determined the level of kinship between seropositive and seronegative animal groups and found no significant difference, suggesting that horizontal virus transmission in the studied population was the same within and among the hatches. Our findings are the first genetic detection of DOBV in rodents in Serbia. We confirm wide and continuous hantavirus presence in the examined parts of the Balkans, underlying the necessity of continual monitoring of hantavirus circulation in A. flavicollis. PMID:24867363

Stamenkovi?, G; Nikoli?, V; Blagojevi?, J; Bugarski-Stanojevi?, V; Adna?evi?, T; Stanojevi?, M; Vujoševi?, M

2015-03-01

83

Intrinsic Tryptophan Fluorescence in the Detection and Analysis of Proteins: A Focus on Förster Resonance Energy Transfer Techniques  

PubMed Central

Förster resonance energy transfer (FRET) occurs when the distance between a donor fluorophore and an acceptor is within 10 nm, and its application often necessitates fluorescent labeling of biological targets. However, covalent modification of biomolecules can inadvertently give rise to conformational and/or functional changes. This review describes the application of intrinsic protein fluorescence, predominantly derived from tryptophan (?EX ? 280 nm, ?EM ? 350 nm), in protein-related research and mainly focuses on label-free FRET techniques. In terms of wavelength and intensity, tryptophan fluorescence is strongly influenced by its (or the protein’s) local environment, which, in addition to fluorescence quenching, has been applied to study protein conformational changes. Intrinsic Förster resonance energy transfer (iFRET), a recently developed technique, utilizes the intrinsic fluorescence of tryptophan in conjunction with target-specific fluorescent probes as FRET donors and acceptors, respectively, for real time detection of native proteins. PMID:25490136

Ghisaidoobe, Amar B. T.; Chung, Sang J.

2014-01-01

84

Nanocrystalline Tin Oxide Nanofibers Deposited by a Novel Focused Electrospinning Method. Application to the Detection of TATP Precursors  

PubMed Central

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

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

2014-01-01

85

Optical imaging of high-frequency focused ultrasonic field using a Nomarski interferometer coupled with multichannel lock-in detection  

NASA Astrophysics Data System (ADS)

We present a nondestructive optical technique for quantitatively imaging a focused ultrasonic field in continuous-wave mode within clear media. We used a Nomarski interferometer configuration coupled with a couple charge device array and multichannel lock-in detection. A two-dimensional full-field image of pressure amplitude can be obtained in only one acquisition. This method was experimentally demonstrated with a high-frequency ultrasonic transducer and experimental measurements of acoustic pressure obtained at 27 MHz. This technique is very interesting because it does not introduce any disturbance in the ultrasonic field and does not need any scanning mechanisms to acquire images. It can be useful for probing high-frequency acoustic fields and for calibrating HF-piezo-electric transducers.

Baït, Lyès; Femmam, Smain; Claude Boccara, A.; Roger, Jean Paul

2012-07-01

86

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

PubMed

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

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

2014-01-01

87

In vivo multispectral, multiparameter, photoacoustic lymph flow cytometry with natural cell focusing, label-free detection and multicolor nanoparticle probes.  

PubMed

Compared with blood tests, cell assessment in lymphatics is not well-established. The goal of this work was to develop in vivo lymph tests using the principles of flow cytometry. Cells in living animals were counted by laser (420-2,300 nm) generation of photoacoustic (PA) signals in individual cells hydrodynamically focused by lymph valves into a single file flow, and using endogenous absorption as intrinsic cell-specific markers, or gold nanorods, nanoshells, and carbon nanotubes as multicolor probes. PA data were verified by high-speed transmission, photothermal, and fluorescent imaging. Counting of melanoma and immune-related cells in normal, apoptotic, and necrotic states in lymphatics in vivo was demonstrated to have the unprecedented sensitivity as one metastatic cell among millions of white blood cells. The time-resolved PA spectral identification of flowing cells was achieved using multicolor labels and laser pulses of different wavelengths and time delays. Multiparameter, noninvasive, portable flow cytometer can be used for preclinical studies on animals with the potential of translation to humans for in vivo PA mapping of colorless lymph vessels and sentinel nodes with simultaneous single cell detection and metastasis assessment without labeling or use of contrast dyes and/or novel low-toxic multicolor probes with different absorption spectra. PMID:18677768

Galanzha, Ekaterina I; Shashkov, Evgeny V; Tuchin, Valery V; Zharov, Vladimir P

2008-10-01

88

Ion creation, ion focusing, ion/molecule reactions, ion separation, and ion detection in the open air in a small plastic device.  

PubMed

A method is presented in which ions are generated and manipulated in the ambient environment using polymeric electrodes produced with a consumer-grade 3D printer. The ability to focus, separate, react, and detect ions in the ambient environment is demonstrated and the data agree well with simulated ion behaviour. PMID:25475256

Baird, Zane; Wei, Pu; Cooks, R Graham

2015-02-01

89

Saving cells from ultrasound-induced apoptosis: quantification of cell death and uptake following sonication and effects of targeted calcium chelation  

PubMed Central

Applications of ultrasound for non-invasive drug and gene delivery have been limited by associated cell death due to sonication. In this study, we sought to quantify the distribution of cellular bioeffects caused by low-frequency ultrasound (24 kHz) and test the hypothesis that Ca2+ chelation after sonication can shift this distribution by saving cells from death by apoptosis. Using flow cytometry, we quantitatively categorized sonicated cells among four populations: (1) cells that appear largely unaffected, (2) cells reversibly permeabilized, (3) cells rendered nonviable during sonication and (4) cells that appear to be viable shortly after sonication, but later undergo apoptosis and die. By monitoring cells for 6 h after ultrasound exposure, we found that up to 15% of intact cells fell into this final category. Those apoptotic cells initially had the highest levels of uptake of a marker compound, calcein; also had highly elevated levels of intracellular Ca2+; and contained an estimated plasma membrane wound radius of 100 – 300 nm. Finally, we showed that chelation of intracellular Ca2+ after sonication reduced apoptosis by up to 44%, thereby providing a strategy to save cells. We conclude that cells can be saved from ultrasound-induced death by appropriate selection of ultrasound conditions and Ca2+ chelation after sonication. PMID:20447754

Hutcheson, J.D.; Schlicher, R.K.; Hicks, H.K.; Prausnitz, M.R.

2010-01-01

90

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

91

???????????????????????????????????????????????????????????????????????????????? THE MEASUREMENT OF PLASMA ELECTRONS TEMPERATURE IN A SMALL PLASMA FOCUS DEVICE BY X-RAY DETECTION TECHNIQUE  

Microsoft Academic Search

??? ???????????????????????????????????????????????????? 3-4 ??????????? ????????????? ????????????????????????????????????????????????????? ????????????????????????????????????????? ????????????????????????????? ???????????????????????????????????????????????????????????????? ??????????????????????????????? ????????????????????????????????????????????????????????? ?????????????????????????????????????????????????????????????????? ? ????????????????????? ???? ??????? ???? ??????? ???? ??????????????? ????? ??????? ?????????????????????????? ?????????????????? ???????????????????????????????????????? ???????????????????????? ??? ???? ???????????????????????????? 5 ???? ???????????????????????????????????????????????????? ????????????????????????????????????????????????????????????????????????????????????????? ????????????? ??????????????????????????????? 1.5 keV ??? 10 keV Abstract: A small plasma focus device with a 3.3 kJ energy operating at 15 kV is a source of intense

Titisak Kulkoulprakar; Rattachat Mongkolnavin

92

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 1 dm(3) high-pressure reactor at 30 °C/80 bar. A view cell positioned in-line with the sonic vessel allowed observation of a turbid emulsion which lasted approximately 30 min 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 95 W cm(-2)) were obtained with those reported for a 87 cm(3) reactor (1.8±0.2×10(-3) s(-1) at 105 W cm(-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

2014-01-01

93

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

PubMed Central

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

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

2012-01-01

94

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

PubMed

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

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

2012-01-01

95

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

PubMed Central

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

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

2014-01-01

96

Exploring recruitment barriers and facilitators in early cancer detection trials: the use of pre-trial focus groups  

PubMed Central

Background Recruiting to randomized controlled trials is fraught with challenges; with less than one third recruiting to their original target. In preparation for a trial evaluating the effectiveness of a blood test to screen for lung cancer (the ECLS trial), we conducted a qualitative study to explore the potential barriers and facilitators that would impact recruitment. Methods Thirty two people recruited from community settings took part in four focus groups in Glasgow and Dundee (UK). Thematic analysis was used to code the data and develop themes. Results Three sub-themes were developed under the larger theme of recruitment strategies. The first of these themes, recruitment options, considered that participants largely felt that the invitation to participate letter should come from GPs, with postal reminders and face-to-face reminders during primary care contacts. The second theme dealt with understanding randomization and issues related to the control group (where bloods were taken but not tested). Some participants struggled with the concept or need for randomization, or for the need for a control group. Some reported that they would not consider taking part if allocated to the control group, but others were motivated to take part even if allocated to the control group by altruism. The final theme considered perceived barriers to participation and included practical barriers (such as flexible appointments and reimbursement of travel expenses) and psychosocial barriers (such as feeling stigmatized because of their smoking status and worries about being coerced into stopping smoking). Conclusions Focus groups provided useful information which resulted in numerous changes to proposed trial documentation and processes. This was in order to address participants information needs, improve comprehension of the trial documentation, enhance facilitators and remove barriers to participation. The modifications made in light of these findings may enhance trial recruitment and future trials may wish to consider use of pretrial focus groups. PMID:24678918

2014-01-01

97

Extending the detection limit of dopants for focused ion beam prepared semiconductor specimens examined by off-axis electron holography  

NASA Astrophysics Data System (ADS)

Silicon specimens containing p-n junctions have been prepared for examination by off-axis electron holography using focused ion beam (FIB) milling. FIB milling modifies the surfaces of the specimens due to gallium implantation and the creation of defects which has the effect of reducing the active dopant concentration measured during electrical characterization. Here we show that although this damage can be removed by using low temperature annealing, the presence of surface charge will modify the electrical potentials in the specimens and limit the dopant concentration that can be measured.

Cooper, David; Rivallin, Pierrette; Hartmann, Jean-Michel; Chabli, Amal; Dunin-Borkowski, Rafal E.

2009-09-01

98

Molecular Detection of Leishmania in Phlebotomine Sand Flies (Diptera: Psychodidae) from a Cutaneous Leishmaniasis Focus at Xakriabá Indigenous Reserve, Brazil  

PubMed Central

Autochthonous cases of American cutaneous leishmaniasis (ACL) have been reported since 2001 in the Xakriabá Indigenous Reserve located in the municipality of São João das Missões in northern Minas Gerais state, Brazil. In order to study the presence of Leishmania DNA in phlebotomine sand flies, six entomological collections were carried out from July 2008 through July 2009, using 40 light traps placed in peridomicile areas of 20 randomly selected houses. From October 2011 through August 2012, another six collections were carried out with 20 light traps distributed among four trails (five traps per trail) selected for a previous study of wild and synanthropic hosts of Leishmania. A total of 4,760 phlebotomine specimens were collected belonging to ten genera and twenty-three species. Single female specimens or pools with up to ten specimens of the same locality, species and date, for Leishmania detection by molecular methods. Species identification of parasites was performed with ITS1 PCR-RFLP using HaeIII enzyme and genetic sequencing for SSU rRNA target. The presence of Leishmania DNA was detected in eleven samples from peridomicile areas: Lu. longipalpis (two), Nyssomyia intermedia (four), Lu. renei (two), Lu. ischnacantha, Micropygomyia goiana and Evandromyia lenti (one pool of each specie). The presence of Leishmania DNA was detected in twelve samples from among the trails: Martinsmyia minasensis (six), Ny. intermedia (three), Mi. peresi (two) and Ev. lenti (one). The presence of Leishmania infantum DNA in Lu. longipalpis and Leishmania braziliensis DNA in Ny. intermediasupport the epidemiological importance of these species of sand flies in the cycle of visceral and cutaneous leishmaniasis, respectively. The results also found other species associated with Leishmania DNA, such as Mt. minasensis and Ev. lenti, which may participate in a wild and/or synanthropic cycle of Leishmania transmission in the studied area. PMID:25853254

Rêgo, Felipe Dutra; Rugani, Jeronimo Marteleto Nunes; Shimabukuro, Paloma Helena Fernandes; Tonelli, Gabriel Barbosa; Quaresma, Patrícia Flávia; Gontijo, Célia Maria Ferreira

2015-01-01

99

State-of-the-art of imaging detecting endoleaks post-EVAR with special focus on low-flow endoleaks.  

PubMed

Endovascular aortic repair (EVAR) necessitates lifelong surveillance for the patient, in order to detect complications timely. Endoleaks (ELs) are among the most common complications of EVAR. Especially type II ELs can have a very unpredictable clinical course and this can range from spontaneous sealing to aortic rupture. Subgroups of this type of EL need to be identified in order to make a proper risk stratification. Aim of this review is to describe the existing imaging techniques, including their advantages and disadvantages in the context of post-EVAR surveillance with a particular emphasis on low-flow ELs. Low flow ELs cause pressurization of the aortic aneurysm sac with a low velocity filling, leading to difficulty of detection by routine imaging protocols for EVAR surveillance, e.g. bi- or triphasic multislice computed tomographic angiography, magnetic resonance imaging and contrast enhanced ultrasound. In this article, we review the imaging possibilities of ELs and discuss the different imaging strategies available for depicting low flow ELs. PMID:24975736

Von Tengg-Kobligk, H; Correa Londono, M; Von Allmen, R; Heverhagen, J T; Van Den Berg, J C

2014-10-01

100

Selenium speciation by coupling vesicle mediated HPLC with off-line ETAAS and on-line focused microwave digestion HG-AAS detection.  

PubMed

A novel High Performance Liquid Chromatography (HPLC) method for the separation of selenium species with specific detection by off-line Electrothermal Atomization Atomic Absorption Spectrometry (ETAAS) or on-line focused microwave digestion (MW) Hydride Generation Atomic Absorption Spectrometry (HG-AAS) is described. Vesicular mobile phases of the cationic surfactant didodecyldimethylammonium bromide (DDAB) have been evaluated for the liquid chromatographic separation of inorganic selenium (selenite and selenate) and different selenoaminoacids (selenocystine, selenomethionine and selenoethionine) on a C(18) reversed-phase column modified by DDAB molecules. The effects of different parameters (pH, buffer and vesicle concentrations) of the mobile phase on the retention times have been determined. The detection limit for selenium with the proposed off-line HPLC-ETAAS method has been found to be 5 microg/L of Se. The detection limit using HPLC-"on line" focused microwave digestion-HG-AAS has been found to be 1 microg/L of Se, with a precision (repeatability) better than +/- 5%. The latter proved to be an exceptional on-line real-time chromatographic detector for selenium speciation purposes. PMID:15045326

Marchante-Gayón, J M; González, J M; Fernández, M L; Blanco, E; Sanz-Medel, A

1996-06-01

101

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

102

Detection efficiency vs. cathode and anode separation in cylindrical vacuum photodiodes used for measuring x-rays from plasma focus device.  

PubMed

A qualitative study on the performance of cylindrical vacuum photodiodes (VPDs) for x-ray detection in plasma focus device has been carried out. Various parameters of VPD such as electrode's diameter, electrode's separation, and its sensitivity are experimentally tested in plasma focus environment. For the first time it is found experimentally that the electrode-separation in the lateral direction of the two coaxial electrodes of cylindrical VPD also plays an important role to increase the efficiency of the detector. The efficiency is found to be highest for the detector with smaller cathode-anode lateral gap (1.5 mm) with smaller photo cathode diameter (10 mm). A comparison between our VPD with PIN (BPX-65) diode as an x-ray detector has also been made. PMID:22047294

Borthakur, T K; Talukdar, N; Neog, N K; Rao, C V S; Shyam, A

2011-10-01

103

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. PMID:24075350

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

104

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

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

105

AuGa2 on focused Ga ion beam-fabricated Au nanorod array for trace detection of melamine cyanurate in milk solution  

NASA Astrophysics Data System (ADS)

Au nanorod arrays were fabricated using a focused gallium (Ga) ion beam (fibAu_NRs) with various levels of Ga ion energy. The formation of AuGa2 on fibAu_NRs was controlled by adjusting the level of Ga ion energy and subsequent heat treatment in order to increase the effect of surface-enhanced Raman scattering (SERS). The SERS enhancement factor of the substrates was evaluated using crystal violet as a molecular test probe. The results show that low-density AuGa2 formation on fibAu_NRs increases the SERS effect, which is likely due to the interjunction charge transfer between Au and AuGa2. An optimized AuGa2 on fibAu_NRs was applied to the trace detection of melamine cyanurate in milk solution with high measured sensitivity.

Sivashanmugan, Kundan; Liao, Jiunn-Der; Haochih Liu, Bernard; Chieh Yu, Li

2015-01-01

106

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

PubMed

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

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

2012-06-01

107

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

PubMed Central

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

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

2012-01-01

108

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

PubMed Central

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

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

2014-01-01

109

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

PubMed Central

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

2014-01-01

110

Detection and molecular typing of Leishmania tropica from Phlebotomus sergenti and lesions of cutaneous leishmaniasis in an emerging focus of Morocco  

PubMed Central

Background Cutaneous leishmaniasis is an infectious disease caused by flagellate protozoa of the genus Leishmania. In Morocco, anthroponotic cutaneous leishmaniasis due to Leishmania tropica is considered as a public health problem, but its epidemiology has not been fully elucidated. The main objective of this study was to detect Leishmania infection in the vector, Phlebotomus sergenti and in human skin samples, in the El Hanchane locality, an emerging focus of cutaneous leishmaniasis in central Morocco. Methods A total of 643 sand flies were collected using CDC miniature light traps and identified morphologically. Leishmania species were characterized by ITS1 PCR-RFLP and ITS1-5.8S rRNA gene nested-PCR of samples from 123 females of Phlebotomus sergenti and 7 cutaneous leishmaniasis patients. Results The sand flies collected consisted of 9 species, 7 of which belonged to the genus Phlebotomus and two to the genus Sergentomyia. Phlebotomus sergenti was the most predominant (76.67%). By ITS1 PCR-RFLP Leishmania tropica was found in three Phlebotomus sergenti females and four patients (4/7). Using nested PCR Leishmania tropica was identified in the same three Phlebotomus sergenti females and all the 7 patients. The sequencing of the nested PCR products recognized 7 haplotypes, of which 6 have never been described. Conclusions This is the first molecular detection and identification of Leishmania tropica in human skin samples and Phlebotomus sergenti in support of its vector status in El Hanchane. The finding of seven Leishmania tropica haplotypes underscores heterogeneity of this species at a high level in Morocco. PMID:23890256

2013-01-01

111

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

PubMed Central

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

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

2010-01-01

112

Indefinite focusing  

NASA Astrophysics Data System (ADS)

It is shown that a modulated Gaussian beam undergoes negative refraction at the interface between a positive and negative refractive index material. While the refraction of the beam is clearly negative, the modulation interference fronts are not normal to the group velocity, and thus exhibit a sideways motion relative to the beam---an effect due to the inherent frequency dispersion associated with the negative index medium. A slab of negative index media has been shown to focus both the far-field and the near-field of an electromagnetic source and form an image with resolution better than what is possible with diffraction limited, conventional optics. However, deviations from the ideal material properties, such as dissipation, limit the image resolution. A wide range of the material property parameter space is studied, demonstrating the limits of resolution with numerical results and approximate analytical formulas. The effects of a finite aperture on the imaging are also examined. Wave propagation in materials for which not all of the principle elements of the permeability and permittivity tensors have the same sign is studied. These tensors are neither positive nor negative definite. It is found that a wide variety of effects can be realized in such media, including negative refraction, near-field focusing and high impedance surface reflection. A new type of near field focusing device is analyzed that consists of a bilayer of media with indefinite electromagnetic material property tensors. The dispersion of the media supports propagating waves for any transverse wave vector, which results in a weaker dependence of spatial bandwidth on media lossiness. We show how bilayers of media with negative electromagnetic property tensor elements can be used to construct low, high and band pass spatial filters. These filters possess sharp adjustable roll offs and can operate in the near and far field regimes to select specific spatial variation components or beam angles.

Schurig, David Alan

113

Faculty Focus  

NSDL National Science Digital Library

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

114

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. PMID:21307152

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

115

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

116

Gas chromatography–electron capture detection determination of Dacthal and its diacid metabolite in soil after ultrasound-assisted extraction and in situ focused microwave-assisted derivatization  

Microsoft Academic Search

A quantitative method for the determination of Dacthal and its di-acid metabolite in soil has been developed by coupling ultrasound-assisted\\u000a extraction and microwave-assisted derivatization of the analytes prior to gas chromatography–electron capture detection for\\u000a individual separation and measurement. The main factors affecting both extraction efficiency and derivatization were optimized\\u000a by experimental design methodology. The proposed approach allows extraction of these

A. Caballo-López; M. D. Luque de Castro

2006-01-01

117

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

PubMed Central

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

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

2013-01-01

118

Phlebotomus sergenti in a Cutaneous Leishmaniasis Focus in Azilal Province (High Atlas, Morocco): Molecular Detection and Genotyping of Leishmania tropica, and Feeding Behavior  

PubMed Central

Background Phlebotomus (Paraphlebotomus) sergenti is at least one of the confirmed vectors for the transmission of cutaneous leishmaniasis caused by Leishmania tropica and distributed widely in Morocco. This form of leishmaniasis is considered largely as anthroponotic, although dogs were found infected with Leishmania tropica, suggestive of zoonosis in some rural areas. Methodology and Findings This survey aimed at (i) studying the presence of Leishmania in field caught Phlebotomus sergenti, (ii) investigating genetic diversity within Leishmania tropica and (iii) identifying the host-blood feeding preferences of Phlebotomus sergenti. A total of 4,407 sand flies were collected in three rural areas of Azilal province, using CDC miniature light traps. Samples collected were found to consist of 13 species: Phlebotomus spp. and 3 Sergentomyia spp. The most abundant species was Phlebotomus sergenti, accounting for 45.75 % of the total. 965 female Phlebotomus sergenti were screened for the presence of Leishmania by ITS1-PCR-RFLP, giving a positive rate of 5.7% (55/965), all being identified as Leishmania tropica. Nucleotide heterogeneity of PCR-amplified ITS1-5.8S rRNA gene-ITS2 was noted. Analyses of 31 sequences obtained segregated them into 16 haplotypes, of which 7 contain superimposed peaks at certain nucleotide positions, suggestive of heterozygosity. Phlebotomus sergenti collected were found to feed on a large variety of vertebrate hosts, as determined by Cytochrome b sequencing of the DNA from the blood meals of 64 engorged females. Conclusion Our findings supported the notion that Phlebotomus sergenti is the primary vector of Leishmania tropica in this focus, and that the latter is genetically very heterogeneous. Furthermore, our results might be suggestive of a certain level of heterozygosity in Leishmania tropica population. This finding, as well as the feeding of the vectors on different animals are of interest for further investigation. PMID:25826399

Ajaoud, Malika; Es-Sette, Nargys; Charrel, Rémi N; Laamrani-Idrissi, Abderahmane; Nhammi, Haddou; Riyad, Myriam; Lemrani, Meryem

2015-01-01

119

Comprehensive two-dimensional separation system by coupling capillary reverse-phase liquid chromatography to capillary isoelectric focusing for peptide and protein mapping with laser-induced fluorescence detection.  

PubMed

A comprehensive two-dimensional (2-D) separation system, coupling capillary reverse-phase liquid chromatography (cRPLC) to capillary isoelectric focusing (CIEF), is described for protein and peptide mapping. cRPLC, the first dimension, provided high-resolution separations for salt-free proteins. CIEF, the second dimension with an orthogonal mechanism to cRPLC afforded excellent resolution capability for proteins with efficient protein enrichment. Since all sample fractions in cRPLC effluents could be transferred to the CIEF dimensions, the combination of the two high-efficiency separations resulted in maximal separation capabilities of each dimension. Separation effectiveness of this approach was demonstrated using complex protein/peptide samples, such as yeast cytosol and a BSA tryptic digest. A peak capacity of more than 10 000 had been achieved. A laser-induced fluorescence (LIF) detector, developed for this system, allowed for high-sensitive detection, with a fmol level of peptide detection for the BSA digest. FITC and BODIPY maleimide were used to tag the proteins, and the latter was found better both for separation and detection in our 2-D system. PMID:14518059

Mao, Yu; Zhang, Xiangmin

2003-09-01

120

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

121

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

PubMed Central

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

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

2008-01-01

122

Movement out of focus  

E-print Network

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

Erlewine, Michael Yoshitaka

2014-01-01

123

Alternating phase focused linacs  

DOEpatents

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

Swenson, Donald A. (Los Alamos, NM)

1980-01-01

124

Shock wave focusing phenomena  

Microsoft Academic Search

A review is presented of recent studies of the focusing of concave shock waves in gases, fluids and solids by curved boundaries. Various shock wave focusing apparatus that have been tested are described, including a detonation chamber, a setup for focusing weak blast waves and a configuration for obtaining time-stepped shadowgraphs of converging cylindrical shocks. Sample velocity profile data are

H. Groenig

1986-01-01

125

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

126

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."

127

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

PubMed

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 10(7) 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. PMID:22087933

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

2011-11-01

128

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.

129

Focus: Teaching by Genre.  

ERIC Educational Resources Information Center

The focus of this bulletin is teaching the various literary genres in the secondary English class. Contents include "The Song Within: An Approach to Teaching Poetry,""Teaching Folk-Rock,""Approaches to Teaching Poetry,""Focus on an Elective Program: Twentieth Century Lyrical Poetry,""Hoffman and Poe: Masters of the Grotesque,""Plays: Shared and…

Wimer, Frances N., Ed.

1974-01-01

130

Microfabricated particle focusing device  

DOEpatents

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

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

2013-04-23

131

Flat Focusing Mirror  

PubMed Central

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

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

2014-01-01

132

Wideband plasmonic focusing metasurfaces  

NASA Astrophysics Data System (ADS)

We present a technique for designing wideband focusing metasurfaces. The proposed metasurface consists of unit cells of nanoparticle-based spatial phase shifters distributed over a planar surface. The topology of each spatial phase shifter is based on the design of plasmonic frequency selective surfaces. A true ab-initio design procedure for the proposed reflectarray is also proposed for the desired bandwidth and center frequency. A reflectarray for focusing the entire red spectrum (75 nm) is designed, with full-wave simulation results demonstrating desired focusing.

Saeidi, Chiya; Weide, Daniel van der

2014-08-01

133

MetroFocus  

NSDL National Science Digital Library

Metro Focus is a multi-platform news magazine focusing on the New York region. The program includes commentary on current events, in-depth reporting, and news updates on areas such as education, transportation, and poverty. Visitors can look around at the organization's programs via the Topics tab at the top of the page and also just scroll through recent episodes which cover everything from the history of Brooklyn, the state of affordable health care in New York, and solutions to assist the chronically homeless. The Watch MetroFocus area affords access to hundreds of complete episodes.

134

Final focus test beam  

SciTech Connect

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

Not Available

1991-03-01

135

Inertial focusing in microfluidics.  

PubMed

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

Martel, Joseph M; Toner, Mehmet

2014-07-11

136

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

137

Time focusing of nutrons  

Microsoft Academic Search

The possibility of time focusing for very slow neutrons is considered. This focusing may prove very useful in solving the\\u000a problem of accumulating ultracold neutrons in a trap that are generated by a pulsed source. Diffraction at a phase grating\\u000a moving across a beam or resonance neutron-spin flip is proposed to implement time-controlled changes in the neutron energy.

A. I. Frank; R. Gähler

2000-01-01

138

Focus of an Earthquake  

NSDL National Science Digital Library

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

McGraw-Hill

139

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

140

EDITORIAL: Focus on Plasmonics FOCUS ON PLASMONICS  

NASA Astrophysics Data System (ADS)

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

Bozhevolnyi, Sergey; García-Vidal, Francisco

2008-10-01

141

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

142

Tate Online: In Focus  

NSDL National Science Digital Library

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

143

Sagittal focusing Laue monochromator  

SciTech Connect

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

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

2009-03-24

144

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

145

Focus on the President.  

ERIC Educational Resources Information Center

An interview with the new president of the Association of Schools and Colleges of Optometry, John Schoessler, considers issues the president wishes to focus on during his presidency, changes in optometry students over the years, people who influenced his educational ideas, and research currently being conducted at Ohio State University College of…

Optometric Education, 2000

2000-01-01

146

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

147

Theme: Focus on Teaching.  

ERIC Educational Resources Information Center

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

Connors, James J.; And Others

1996-01-01

148

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

149

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

150

Video controlled FLIR focus  

Microsoft Academic Search

The objective of the program was to invent, design, breadboard and demonstrate an automatic focusing device and a dynamic range expansion system to be used with FLIR sensors. The scene analysis, breadboard implementation and test results of both tasks are covered.

E. Elwell; J. Lewis; K. Stelzenmuller

1976-01-01

151

Immigrant Education. IDRA Focus.  

ERIC Educational Resources Information Center

This newsletter includes five articles on immigrant education that focus on successful school programs and educational policy issues. In "Immigrant Education from the Administrators' Perspective" (Pam McCollum, Juanita Garcia), three principals of south Texas secondary schools with successful immigrant programs discuss their views on the adequacy…

IDRA Newsletter, 1996

1996-01-01

152

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

153

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

154

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

155

[Focus: Family Communication].  

ERIC Educational Resources Information Center

This issue of the "Journal of the Wisconsin Communication Association" focuses on family communication and contains the following articles: "Marital Typologies: An Alternative Approach to the Study of Communication in Enduring Relations" by Mary Anne Fitzpatrick, "Intimate Communication and the Family" by Marilyn D. LaCourt, and "A Study in…

Barnes, Richard E., Ed.

1977-01-01

156

Instructional Technology. IDRA Focus.  

ERIC Educational Resources Information Center

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

IDRA Newsletter, 1997

1997-01-01

157

Faculty Focus: Alumni Update  

E-print Network

about how ocean acidification will impact marine biota and whether ecosystems will be able to adapt. I fellows, and staff conduct cutting-edge research on critical issues such as ocean acidification, which1 1 From the Director Faculty Focus: Gordon Holtgrieve Alumni Update Consider a Gift Ocean

Washington at Seattle, University of

158

REPRODUCTIONREVIEW Focus on Meiosis  

E-print Network

REPRODUCTIONREVIEW Focus on Meiosis Stops and starts in mammalian oocytes: recent advances grow and undergo meiosis within ovarian follicles. Oocytes are arrested at the first meiotic prophase stimulates the immature oocyte to resume meiosis. Meiotic arrest depends on a high level of cAMP within

Terasaki, Mark

159

REPRODUCTIONREVIEW Focus on Meiosis  

E-print Network

REPRODUCTIONREVIEW Focus on Meiosis Not all germ cells are created equal: Aspects of sexual dimorphism in mammalian meiosis Meisha A Morelli and Paula E Cohen Department of Biomedical Sciences, Cornell.edu Abstract The study of mammalian meiosis is complicated by the timing of meiotic events in females

Cohen, Paula

160

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

161

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

162

Focusing educational initiatives  

NASA Technical Reports Server (NTRS)

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

Parks, George K.

1990-01-01

163

Outbound Intrusion Detection  

Microsoft Academic Search

This paper describes a variation to the traditional intrusion detection approach motivated by longstanding challenges and recent trends in information security. Intrusion detection systems have historically focused on the protection of local resources by identifying signs of malicious activity that may help administrators prevent a break-in and limit its effects. Outbound intrusion detection focuses, not on preventing a host from

Salvador Mandujano; Arturo Galv

164

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

165

Focus on quantum efficiency  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

166

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

167

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

168

Recent plasma focus research  

Microsoft Academic Search

The paper shows that the recently reported high pressure limit for the operation of Mather-type plasma focus devices makes discrimination difficult between the scaling laws proposed for the neutron yield. Experimental results are examined, and it is suggested that this limit may explain some well-known contingencies in neutron production. Finally, attention is given to the interpretation of X-ray anisotropy measurements

A. Banuelos; H. Bruzzone; R. Delellis; J. Gratton; R. Gratton; H. Kelly; M. Milanese; J. Pouzo; F. R. Trelles

1979-01-01

169

Bring it into Focus  

NSDL National Science Digital Library

In this activity (page 2 of PDF), learners play with a lens and a piece of paper to focus an image on the paper. Learners look at different things, and see how the lenses affect the image. The "Going Further" section includes some background info about how this lens is similar to how a camera lens works, and how our eye works. The fact that the image is upside down is compensated in our eye by our brain!

OMSI

2004-01-01

170

Nature Web Focus: SARS  

NSDL National Science Digital Library

The journal Nature offers this free Web focus on Severe Acute Respiratory Syndrome (SARS), in which Nature's reporters pose key questions about the outbreak, and assess our preparedness to deal with future viral threats. Reader will find dozens of articles, including editorials, Science Updates, and Brief Communications from the journal. The articles trace the chronology of the SARS epidemic, and the section titled What Have We Learned? offers an excellent overview of what we know and what remains to be seen.

2007-12-12

171

Globalization in Focus  

NSDL National Science Digital Library

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

2001-01-01

172

Fedgazette Focus: Hog Markets  

NSDL National Science Digital Library

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

1999-01-01

173

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

174

Focused on Robert E  

NASA Technical Reports Server (NTRS)

This image, taken by the microscopic imager on the Mars Exploration Rover Opportunity, shows a geological feature dubbed 'Robert E.' Light from the top is illuminating the feature, which is located within the rock outcrop at Meridiani Planum, Mars. Several images, each showing a different part of 'Robert E' in good focus, were merged to produce this view. The area in this image, taken on Sol 15 of the Opportunity mission, is 2.2 centimeters (0.8 inches) across.

2004-01-01

175

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

176

Flux focusing eddy current probe  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

177

6A-4 Focused Ultrasound Potential to Initiate Spreading Depression for Disruption of Blood Brain Barrier  

Microsoft Academic Search

Blood-brain barrier (BBB) has long been known to impede the delivery of therapeutic and diagnostic agents into the central nervous system. Although ultrasound with microbubbles has been shown to disrupt the BBB, we presently examine another ultrasound-induced mechanism for opening of the BBB: ultrasound induction of spreading depression. In this process, local physical changes induced by the ultrasound pressure field,

Natalia Vykhodtseva; Irina Konopatskaya

2007-01-01

178

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

179

SecurityFocus  

NSDL National Science Digital Library

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

180

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

181

Nutrition News Focus  

NSDL National Science Digital Library

Written by David M. Klurfeld, Professor and Chairman of the Department of Nutrition and Food Science at Wayne State University in Detroit, this free, daily newsletter offers concise nutrition tips and analyses of breaking nutrition news. Nutrition News Focus aims at delivering information that ordinary people can use and understand, with a minimum of jargon and no tolerance for "mumbo-jumbo." Users can subscribe to the newsletter at the site. Subscribers receive one short mailing per day, with the topic briefly described and followed by analysis. Old newsletters are added to the archive two weeks after publication, and users can browse the archive by issue date or topic.

182

Transverse field focused system  

DOEpatents

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

Anderson, Oscar A. (Berkeley, CA)

1986-01-01

183

Isoelectric focusing in space  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

184

Micro-focused ultrasonic solid-liquid extraction (muFUSLE) combined with HPLC and fluorescence detection for PAHs determination in sediments: optimization and linking with the analytical minimalism concept.  

PubMed

Analytical minimalism is a concept that deals with the optimization of all stages of an analytical procedure so that it becomes less time, cost, sample, reagent and energy consuming. The guide-lines provided in the USEPA extraction method 3550B recommend the use of focused ultrasound (FU), i.e., probe sonication, for the solid-liquid extraction of Polycyclic Aromatic Hydrocarbons, PAHs, but ignore the principle of analytical minimalism. The problems related with the dead sonication zones, often present when high volumes are sonicated with probe, are also not addressed. In this work, we demonstrate that successful extraction and quantification of PAHs from sediments can be done with low sample mass (0.125g), low reagent volume (4ml), short sonication time (3min) and low sonication amplitude (40%). Two variables are here particularly taken into account for total extraction: (i) the design of the extraction vessel and (ii) the solvent used to carry out the extraction. Results showed PAHs recoveries (EPA priority list) ranged between 77 and 101%, accounting for more than 95% for most of the PAHs here studied, as compared with the values obtained after soxhlet extraction. Taking into account the results reported in this work we recommend a revision of the EPA guidelines for PAHs extraction from solid matrices with focused ultrasound, so that these match the analytical minimalism concept. PMID:18970118

Capelo, J L; Galesio, M M; Felisberto, G M; Vaz, C; Pessoa, J Costa

2005-06-15

185

Alliance-Focused Training.  

PubMed

Alliance-focused training (AFT) aims to increase therapists' ability to recognize, tolerate, and negotiate alliance ruptures by increasing the therapeutic skills of self-awareness, affect regulation, and interpersonal sensitivity. In AFT, therapists are encouraged to draw on these skills when metacommunicating about ruptures with patients. In this article, we present the 3 main supervisory tasks of AFT: videotape analysis of rupture moments, awareness-oriented role-plays, and mindfulness training. We describe the theoretical and empirical support for each supervisory task, provide examples based on actual supervision sessions, and present feedback about the usefulness of the techniques from trainees in our program. We also note some of the challenges involved in conducting AFT and the importance of maintaining a strong supervisory alliance when using this training approach. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:25150677

Eubanks-Carter, Catherine; Christopher Muran, J; Safran, Jeremy D

2014-08-25

186

In Focus: The Tree  

NSDL National Science Digital Library

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

187

Highly Focused Supersonic Microjets  

NASA Astrophysics Data System (ADS)

This paper describes the production of thin, focused microjets with velocities of up to 850m/s by the rapid vaporization of a small mass of liquid in an open liquid-filled capillary. The vaporization is caused by the absorption of a low-energy laser pulse. A likely explanation of the observed phenomenon is based on the impingement of the shock wave caused by the nearly instantaneous vaporization on the free surface of the liquid. We conduct an experimental study of the dependence of the jet velocity on several parameters and develop a semiempirical relation for its prediction. The coherence of the jets and their high velocity, good reproducibility, and controllability are unique features of the system. A possible application is to development of needle-free drug-injection systems that would be of great importance for health care worldwide.

Tagawa, Yoshiyuki; Oudalov, Nikolai; Visser, Claas Willem; Peters, Ivo R.; van der Meer, Devaraj; Sun, Chao; Prosperetti, Andrea; Lohse, Detlef

2012-07-01

188

Retroreflection Focusing Schlieren System  

NASA Technical Reports Server (NTRS)

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

Heineck, James T. (Inventor)

1996-01-01

189

Science in Focus  

NSDL National Science Digital Library

Sumanas Inc.'s website offers a wide range of material, such as animations of scientific processes, for a range of scientific disciplines, but here visitors will find their "Science in Focus" section of the website. Some of the topics that are brought to life with animating technology are antibiotic resistance, stem cell research, malaria, anthrax, gene therapy, and peptic ulcers. Click on "Go to Presentation" next to your topic of choice, and you'll be taken to a page that has the animation ready to play, but also has several links to outside sources of information. When you're ready to view the animation, click on the link "Click to view animation" and you'll be shown a simple player that will allow you to listen to the narration while viewing the animation, or read the text while viewing the animation. Visitors shouldn't miss the Malaria Parasite animation for an explanation of how humans, mosquitoes, and the Plasmodium parasite all have to be involved to successfully pass on malaria.

190

Latin-Focus  

NSDL National Science Digital Library

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

191

COMPRENDO: Focus and Approach  

PubMed Central

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

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

2006-01-01

192

Isoelectric focusing of proteins and peptides  

NASA Technical Reports Server (NTRS)

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

Egen, N.

1979-01-01

193

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

194

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

195

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

196

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

197

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. PMID:23571670

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

2013-01-01

198

Microflow cytometers with integrated hydrodynamic focusing.  

PubMed

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

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

2013-01-01

199

A New Adaptive Focus Measure for Shape From Focus  

Microsoft Academic Search

This paper proposes a new focus measure operator for Shape From Focus to recover a dense depth map of a scene. The method can handle depth discon- tinuities effectively by using adaptively shaped and weighted support win- dows. The support window shapes and weights are determined from the im- age characteristics of the all-focused image of the scene. Similar and

Tarkan Aydin; Yusuf Sinan Akgul

2008-01-01

200

Hydrodynamic focusing – a versatile tool  

PubMed Central

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

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

2011-01-01

201

Combination of high-intensity focused ultrasound irradiation and hydroxyapatite nanoparticle injection to injure normal goat liver tissue in vivo without costal bone incision.  

PubMed

The aims of this study were to evaluate the in vivo safety of intravenous nano-hydroxyapatite (nano-HA), to explore how nano-HA might influence the effects of high-intensity focused ultrasound (HIFU) on normal liver tissue, and to investigate whether intravenous nano-HA could enhance HIFU for hepatocellular carcinoma ablation in a goat model. The present study, for the first time, indicated that the delivery of abundant nano-HA into the body over short periods of time could be assembled by the hepatic reticuloendothelial system, subsequently leading to a rapid rise of ultrasound-induced overheating, and ultimately resulting in enlargement of the coagulation necrotic area for ablated hepatocellular carcinoma in goats both in vivo and ex vivo. On the other hand, therapeutic doses of nano-HA were much lower than the lethal dose, and consequently presented transient and mild abnormalities of hepatic enzymes and renal function during the first 24 h after nano-HA injection. These results suggested that the combined application of nano-HA and HIFU is potentially a more effective alternative option compared to surgery for hepatocellular carcinoma local ablation in a safe and feasible manner. PMID:25366724

Liu, L; Xiao, Z; Xiao, Y; Wang, Z; Li, F; Li, M; Peng, X

2014-01-01

202

Dual focus diffractive optical element with extended depth of focus  

NASA Astrophysics Data System (ADS)

A dual focus property and an extended depth of focus were verified by a new type of diffractive lens displaying on liquid crystal on silicon (LCoS) devices. This type of lens is useful to read information on multilayer optical discs and tilted discs. The radial undulation of the phase groove on the diffractive lens gave the dual focus nature. The focal extension was performed by combining the dual focus lens with the axilens that was invented for expanding the depth of focus. The number of undulations did not affect the intensity along the optical axis but the central spot of the diffraction pattern.

Uno, Katsuhiro; Shimizu, Isao

2014-09-01

203

Focus On.... Organic Farming and  

E-print Network

Focus On.... Organic Farming and Agriculture This resource guide aims to provide useful, detailed, high quality sources of information on organic farming and agriculture for students in Higher;Focus on Organic Farming/Agriculture Introduction

Miranda, Eduardo Reck

204

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

205

Pyramid based depth from focus  

Microsoft Academic Search

A method is presented for depth recovery through the analysis of scene sharpness across changing focus position. Modeling a defocused image as the application of a low pass-filter on a properly focused image of the same scene, the authors can compare the high spatial frequency content of regions in each image and determine the correct focus position. Recovering depth in

Trevor Darrell; Kwangyoen Wohn

1988-01-01

206

Community Gardens Focus Group Report  

E-print Network

Community Gardens Focus Group Report Produced for Auckland City Council July 2002 Auckland University of Technology #12;Community Gardens Focus Groups A series of 3 focus groups were conducted over 2 Council regarding Community Gardens. The groups consisted of 6-8 people in each with the following

207

Ultrasound-induced acoustophoretic motion of microparticles in three dimensions  

E-print Network

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

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

2013-01-01

208

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

209

Shape from focus using fast discrete curvelet transform  

Microsoft Academic Search

A new method for focus measure computation is proposed to reconstruct 3D shape using image sequence acquired under varying focus plane. Adaptive histogram equalization is applied to enhance varying contrast across different image regions for better detection of sharp intensity variations. Fast discrete curvelet transform (FDCT) is employed for enhanced representation of singularities along curves in an input image followed

Rashid Minhas; Abdul Adeel Mohammed; Q. M. Jonathan Wu

2011-01-01

210

Ultrasonic inspection apparatus and method using a focused wave device  

DOEpatents

An ultrasonic pulse echo inspection apparatus and method for detecting structural failures. A focus lens is coupled to the transducer to focus the ultrasonic signal on an area to be inspected and a stop is placed in the focus lens to block selected ultrasonic waves. Other waves are not blocked and are transmitted through the structure to arrive at interfaces therein concurrently to produce an echo response with significantly less distortion.

Gieske, John H. (Albuquerque, NM); Roach, Dennis P. (Albuquerque, NM); Walkington, Phillip D. (Albuquerque, NM)

2001-01-01

211

Shifting focus: Assessing cataloging service through focus groups  

Microsoft Academic Search

Focus groups are a valuable research tool for evaluating library services but they are overlooked as a means of analyzing the performance of internal library units like technical services. In this study, focus group meetings were held with departmental library personnel to gather data related to the perception of centralized cataloging services in the decentralized library system at the University

K. C. Elhard; Qiang Jin

2004-01-01

212

A theory of focus interpretation  

Microsoft Academic Search

According to the alternative semantics for focus, the semantic reflec of intonational focus is a second semantic value, which\\u000a in the case of a sentence is a set of propositions. We examine a range of semantic and pragmatic applications of the theory,\\u000a and extract a unitary principle specifying how the focus semantic value interacts with semantic and pragmatic processes. A

Mats Rooth; Maria Bittner; Peter Blok; Gemraro Chier; Irene Heim; Julia Hirschberg; Manfred Pinkal

1992-01-01

213

Pharmacometrics: Focus on the Patient  

PubMed Central

Pharmacometrics, whether using simple or complex models, has contributed to rational and efficient drug development,1–3 with the main focus on early drug development.4 This article describes why opportunities more directly focused on the patient abound in late stage development, illustrating the concept with three innovative examples which focus on benefits to patients, enabling drugs that are truly efficacious to reach the market faster in diseases with high unmet medical needs, while maintaining adequate safety.

Dumitrescu, T Pene; Fossler, MJ; Schmith, VD

2015-01-01

214

Focus in Relative Clause Construal.  

ERIC Educational Resources Information Center

Discusses two auditory comprehension studies that investigated the role of focus, as conveyed by a pitch accent, in the comprehension of relative clauses preceded by a complex noun phrase. Findings include focus attracts modifiers, and pitch accents for new phrases differ acoustically from pitch accents for contrastive phrases. (46 references)…

Schafer, Amy; And Others

1996-01-01

215

Focus On.... Biodiversity and Conservation  

E-print Network

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

Miranda, Eduardo Reck

216

Focused Crawling Using Context Graphs  

Microsoft Academic Search

Maintaining currency of search engine indices by exhaustive crawling is rapidly becoming impossi- ble due to the increasing size and dynamic content of the web. Focused crawlers aim to search only the subset of the web related to a specific cate- gory, and offer a potential solution to the currency problem. The major problem in focused crawl- ing is performing

Michelangelo Diligenti; Frans Coetzee; Steve Lawrence; C. Lee Giles; Marco Gori

2000-01-01

217

Depth from focusing and defocusing  

Microsoft Academic Search

The problem of obtaining depth information from focusing and defocusing is studied. In depth from focusing, instead of the Fibonacci search, which is often trapped in local maxima, the combination of Fibonacci search and curve fitting is proposed. This combination leads to an unprecedentedly accurate result. A model of the blurring effect that takes geometric blurring as well as imaging

Yalin Xiong; Steven A. Shafer

1993-01-01

218

Doing Focus-on-Form.  

ERIC Educational Resources Information Center

Considers the rationale for using a focus on form approach to teaching form as opposed to the more traditional focus on forms approach where linguistic features are treated sequentially. Describes methodological options for attending to form in communication. (Author/VWL)

Ellis, Rod; Basturkmen, Helen; Loewen, Shawn

2002-01-01

219

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

2010-10-01

220

Prime focus instrument of prime focus spectrograph for Subaru telescope  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

221

Early Detection Research Worldwide  

Cancer.gov

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

222

Compact electron beam focusing column  

SciTech Connect

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

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

2001-07-13

223

Wayside Teaching: Focusing on Relationships  

NSDL National Science Digital Library

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

Sara Davis Powell

224

Wolter Optics for Neutron Focusing  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

225

Statistical Mechanics with focus on  

E-print Network

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

Johannesson, Henrik

226

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

227

Wayside Teaching: Focusing on Relationships  

ERIC Educational Resources Information Center

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

Powell, Sara Davis

2011-01-01

228

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. PMID:21117663

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

2010-01-01

229

Nature Web Focus: Ocean Genomics  

NSDL National Science Digital Library

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

2003-01-01

230

Focused Multi-pinhole SPECT  

Microsoft Academic Search

This thesis describes the development and validation of image acquisition methods and reconstruction techniques of focused small animal multi-pinhole Single Photon Emission Computed Tomography (SPECT). Multi-pinhole SPECT can achieve sub-half-millimeter resolution with very high sensitivity by employing collimators with multiple pinholes that are focused at the same centrally located region. The U-SPECT-II, a small-animal SPECT scanner developed at UMC Utrecht,

W. J. Branderhorst

2011-01-01

231

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

232

AXAF SIM focus mechanism study  

NASA Technical Reports Server (NTRS)

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

Tananbaum, H. D.; Whitbeck, E.

1994-01-01

233

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

234

SCIENCE-WEEK Focus Reports  

NSDL National Science Digital Library

SCIENCE-WEEK (described in the June 27, 1997 Scout Report) is an online weekly digest of the news of science, now published by Spectrum Press Inc. Formerly a completely free service, SCIENCE-WEEK now charges a nominal fee for its current awareness services. However, several Focus Reports are currently available on-site for free (visitors may also wish to browse the table of contents for past SCIENCE-WEEK issues). Focus Reports explain and summarize (in clear language!) cutting-edge science and provide syntheses of current research, including the date and source of recent publication. Publication sources generally include Science, Nature, Scientific American, and Proc. Natl. Acad. Sci., among other reputable journals. Current Focus Reports cover topics as varied as Astrophysics, Evolution, and the Biology of Cancer. For those with a strong interest in scientific advances or for those seeking examples of clear but uncompromised scientific explanations, this is an excellent resource.

235

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

236

Speeding chemical reactions by focusing  

E-print Network

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

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

2012-12-13

237

Ballistic dispersion in temperature gradient focusing  

E-print Network

Ballistic dispersion in temperature gradient focusing BY DAVID E. HUBER* AND JUAN G. SANTIAGO systems. Keywords: microfluidics; temperature gradient focusing; kinematic dispersion; Taylor, in particular, microfluidic temperature gradient focusing. Temperature gradient focusing, hereafter `TGF' (Ross

Santiago, Juan G.

238

FINDYOUR FOCUS. 184 degree programs  

E-print Network

FINDYOUR FOCUS. #12;184 degree programs Including: mechanical engineering (Travis's choice-published research journalfor undergraduates. STEM SURE is a summer undergraduate research experience. Selected. ALUMNUS #12;More than 800 students traveled to another country for study abroad courses in 2011-12. WVU

Mohaghegh, Shahab

239

Focus Issue on Metamaterials INTRODUCTION  

E-print Network

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

Shalaev, Vladimir M.

240

Teaching and Learning. IDRA Focus.  

ERIC Educational Resources Information Center

This theme issue includes four articles that focus on teaching and learning strategies to benefit all students, including limited-English-proficient, minority, economically disadvantaged, and at-risk students. "Would You Read Me a Story?: In Search of Reading Strategies That Work for the Early Childhood Classroom" (Hilaria Bauer) discusses how…

IDRA Newsletter, 1997

1997-01-01

241

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

242

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

243

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

244

Axiom directed Focusing long version  

E-print Network

Axiom directed Focusing long version Cl´ement Houtmann Universit´e Henri Poincar´e Nancy 1 & LORIA of computational and reasoning axioms. Although soundness is ensured, using superdeduction and deduction modulo that some hypotheses on the synchrony of reasoning axioms are verified. It implies that cut- elimination

Paris-Sud XI, Université de

245

Creating Wave-Focusing Materials  

E-print Network

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

A. G. Ramm

2008-05-16

246

Undergraduate Research Symposium focusing on  

E-print Network

and to implement alternative and renewable forms of energy in the 21st century. There is hope for our generationUndergraduate Research Symposium focusing on Energy and Climate Change Tuesday, November 16 5 to environmental change and energy use. Climate and Energy Campus Week, a project launched via the initiative

Jiang, Huiqiang

247

Focused Inference Romer E. Rosales+  

E-print Network

Focused Inference R´omer E. Rosales+ and Tommi S. Jaakkola Computer Science and Artificial Intelligence Lab., MIT. Cambridge, MA 02139 + Computer-Aided Diagnosis and Therapy, Siemens Medical Solutions, with the singular exception of [18], do not pro- vide bounds, nor are necessarily guaranteed to con- verge without

Goldwasser, Shafi

248

Focused X-ray source  

DOEpatents

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

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

1990-01-01

249

Math Fair: Focus on Fractions  

ERIC Educational Resources Information Center

This article depicts the rewarding experience of creating mathematical environments for kindergarten and elementary students by focusing on one of the most important and often difficult-to-grasp concepts (fractions) through play methods incorporated into a math fair. The basic concept of a math fair is threefold: (1) to create preplanned,…

Mokashi, Neelima A.

2009-01-01

250

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 students’ thinking and on their work products. This document includes various approaches that coaches may use with teachers to gain trust and important pre-observation and post observation questioning and reflection techniques.

David Foster

251

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

252

Strategy and Focus: Teaching Literature.  

ERIC Educational Resources Information Center

The six articles in this focused journal issue are concerned with literature teaching on the secondary and college level. The titles and authors of the articles are as follows: (1) "Aesthetic Reading and Teaching: 'Candide' Revisited" (Michael G. Gauthier); (2) "Discovery: The Role of Subjective Response in Initiating the Literature Discussion"…

Karolides, Nicholas J., Ed.

1983-01-01

253

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

254

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

255

Tsunami Amplification due to Focusing  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

256

FOREWORD: Focus on Advanced Ceramics Focus on Advanced Ceramics  

NASA Astrophysics Data System (ADS)

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

Ohashi, Naoki

2011-06-01

257

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. PMID:21326641

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

258

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

259

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

260

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)

2011-03-29

261

Focused Observation: Recording A Hike  

NSDL National Science Digital Library

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

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

2012-03-18

262

What is a seizure focus?  

PubMed

The seizure focus is the site in the brain from which the seizure originated and is most likely equivalent to the epileptogenic zone, defined as the area of cerebral cortex indispensable for the generation of clinical seizures. The boundaries of this region cannot be defined at present by any diagnostic test. Imaging and EEG recording can define regions of functional deficit during the interictal period, regions that generate interictal spikes, regions responsible for the ictal symptoms, regions from which the seizure is triggered, and regions of structural damage. However, these regions define the epileptogenic zone only when they are spatially concordant. The frequent discrepancies suggest the essential involvement of synaptically connected regions, that is a distributive focus, in the origination of most seizures. Here we review supporting evidence from animal studies and studies of persons undergoing surgical resection for medically-intractable epilepsy. We conclude that very few of the common seizures are truly local, but rather depend on nodal interactions that permit spontaneous network excitability and behavioral expression. Recognition of the distributive focus underlying most seizures has motivated many surgical programs to upgrade their intracranial studies to capture activity in as much of the network as possible. PMID:25012366

Nadler, J Victor; Spencer, Dennis D

2014-01-01

263

Targeted therapy using nanotechnology: focus on cancer  

PubMed Central

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

Sanna, Vanna; Pala, Nicolino; Sechi, Mario

2014-01-01

264

The focusing DIRC: An innovative PID detector  

NASA Astrophysics Data System (ADS)

The FDIRC (Focusing Detector of Internally Reflected Cherenkov light) is a new concept of PID (Particle IDentification) detector aimed at separating kaons from pions up to a few GeV/c. It is the successor of the BABAR DIRC and benefits from the knowledge accumulated with a first FDIRC prototype built and operated at SLAC. The FDIRC is intended to be used in an environment with a luminosity 100 times higher than for BABAR and Belle. Backgrounds will be higher as well; yet, the FDIRC has been designed to perform at least as well as the BABAR DIRC. The main improvement is a complete redesign of the photon camera, moving from a huge tank of ultra-pure water to much smaller focusing cameras with solid fused-silica optics. Furthermore, the detection chain will be 10 times faster than in BABAR to reject more background and to measure more accurately Cherenkov angles. This is achieved using H-8500 MaPMTs and a new front-end electronics (FEE) with significantly improved timing precision, higher hit rate capability, and small dead time. A full-scale FDIRC prototype covering 1/12th of the barrel azimuth is installed at SLAC and has just started recording cosmic-ray data. In this paper, we summarize the FDIRC design, present the status of the prototype test at SLAC and review the ongoing work to analyse the data.

Borsato, M.; Arnaud, N.; Dey, B.; Nishimura, K.; Leith, D. W. G. S.; Roberts, D.; Ratcliff, B.; Va'vra, J.; Varner, G. S.

2013-12-01

265

Blue diode spectroscopy in a plasma focus device  

Microsoft Academic Search

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

M. Mathuthu; T. G. Zengeni

2004-01-01

266

Recent advances in microfluidic detection systems  

PubMed Central

There are numerous detection methods available for methods are being put to use for detection on these miniaturized systems, with the analyte of interest driving the choice of detection method. In this article, we summarize microfluidic 2 years. More focus is given to unconventional approaches to detection routes and novel strategies for performing high-sensitivity detection. PMID:20414455

Baker, Christopher A; Duong, Cindy T; Grimley, Alix; Roper, Michael G

2009-01-01

267

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.

268

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

269

Focus Issue: Uncovering Immunological Secrets  

NSDL National Science Digital Library

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

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

2007-08-07

270

Rotating apparatus for isoelectric focusing  

NASA Technical Reports Server (NTRS)

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

Bier, Milan (Inventor)

1986-01-01

271

Pain pharmacology: focus on opioids  

PubMed Central

Summary The incidence of chronic pain is estimated to be 20–25% worldwide. Although major improvements in pain control have been obtained, more than 50% of the patients reports inadequate relief. It is accepted that chronic pain, if not adequately and rapidly treated, can become a disease in itself, often intractable and maybe irreversible. This is mainly due to neuroplasticity of pain pathways. In the present review I will discuss about pain depicting the rational for the principal pharmacological interventions and finally focusing on opioids, that represent a primary class of drug to treat pain. PMID:25568646

Fornasari, Diego

2014-01-01

272

FOCUS - Office of Cancer Survivorship  

Cancer.gov

As cancer survivors live longer, and as awareness continues to grow of the potential risks for lingering and late-occurring adverse effects of cancer and its treatment, attention is shifting to the need for a better understanding of the medical follow-up care received by long-term survivors. The Follow-up Care Use Among Survivors (FOCUS) survey was initiated to address this gap in our knowledge and to help identify areas where improvements are needed in quality of post-treatment care.

273

MAMA Spectroscopic Sensitivity and Focus Monitor Cycle 19  

NASA Astrophysics Data System (ADS)

Monitor sensitivity of each MAMA grating mode to detect any change due tocontamination or other causes. Also monitor the STIS focus in a spectroscopic and animaging mode.Obtain exposures in each of the 2 low-resolution MAMA spectroscopic modes every 4 months, in each of the 2 medium-resolution modes once a year, and in each of the 4 echelle modes every 3 months,using unique calibration standards for each mode, and ratio the results to the firstobservations to detect any trends. In addition, each L-mode sequence will be preceded by twospectroscopic ACQ/PEAKs with the CCD/G230LB and crossed linear patterns, with the purpose of measuringthe focus {PSF across the dispersion as a function of UV wavelength}; and each M-mode sequence will be preceded by aCCD/F28X50OII direct image also to monitor the focus.Whenever possible, obtain parallel airglow spectra with COS.

Bostroem, Azalee

2011-10-01

274

MAMA Spectroscopic Sensitivity and Focus Monitor Cycle 21  

NASA Astrophysics Data System (ADS)

Monitor sensitivity of each MAMA grating mode to detect any change due tocontamination or other causes. Also monitor the STIS focus in a spectroscopic and animaging mode.Obtain exposures in each of the 2 low-resolution MAMA spectroscopic modes every 4 months, in each of the 2 medium-resolution modes once a year, and in each of the 4 echelle modes every 3 months,using unique calibration standards for each mode, and ratio the results to the firstobservations to detect any trends. In addition, each L-mode sequence will be preceded by twospectroscopic ACQ/PEAKs with the CCD/G230LB and crossed linear patterns, with the purpose of measuringthe focus {PSF across the dispersion as a function of UV wavelength}; and each M-mode sequence will be preceded by aCCD/F28X50OII direct image also to monitor the focus.Whenever possible, obtain parallel airglow spectra with COS.

Sana, Hugues

2013-10-01

275

MAMA Spectroscopic Sensitivity and Focus Monitor Cycle 20  

NASA Astrophysics Data System (ADS)

Monitor sensitivity of each MAMA grating mode to detect any change due tocontamination or other causes. Also monitor the STIS focus in a spectroscopic and animaging mode.Obtain exposures in each of the 2 low-resolution MAMA spectroscopic modes every 4 months, in each of the 2 medium-resolution modes once a year, and in each of the 4 echelle modes every 3 months,using unique calibration standards for each mode, and ratio the results to the firstobservations to detect any trends. In addition, each L-mode sequence will be preceded by twospectroscopic ACQ/PEAKs with the CCD/G230LB and crossed linear patterns, with the purpose of measuringthe focus {PSF across the dispersion as a function of UV wavelength}; and each M-mode sequence will be preceded by aCCD/F28X50OII direct image also to monitor the focus.Whenever possible, obtain parallel airglow spectra with COS.

Holland, Stephen

2012-10-01

276

MAMA Spectroscopic Sensitivity and Focus Monitor Cycle 18  

NASA Astrophysics Data System (ADS)

Monitor sensitivity of each MAMA grating mode to detect any change due tocontamination or other causes. Also monitor the STIS focus in a spectroscopic and animaging mode.Obtain exposures in each of the 2 low-resolution MAMA spectroscopic modes every 4 months, in each of the 2 medium-resolution modes once a year, and in each of the 4 echelle modes every 3 months,using unique calibration standards for each mode, and ratio the results to the firstobservations to detect any trends. In addition, each L-mode sequence will be preceded by twospectroscopic ACQ/PEAKs with the CCD/G230LB and crossed linear patterns, with the purpose of measuringthe focus {PSF across the dispersion as a function of UV wavelength}; and each M-mode sequence will be preceded by aCCD/F28X50OII direct image also to monitor the focus.Whenever possible, obtain parallel airglow spectra with COS.

Osten, Rachel

2010-09-01

277

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

278

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

279

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

PubMed

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

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

1994-01-01

280

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

281

Development of a Focusing DIRC  

SciTech Connect

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

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

2006-12-12

282

Antipodal focusing of seismic waves observed with the USArray  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

283

Megaloblastic anemia: back in focus.  

PubMed

Megaloblastic anemia (MA), in most instances in developing countries, results from deficiency of vitamin B(12) or folic acid. Over the last two to three decades, incidence of MA seems to be increasing. Of the two micronutrients, folic acid deficiency contributed to MA in a large majority of cases. Now deficiency of B(12) is far more common. In addition to anemia, occurrence of neutropenia and/or thrombocytopenia is increasingly being reported. Among cases presenting with pancytopenia, MA stands out as an important (commonest cause in some series) cause. This article focuses on these and certain other aspects of MA. Possible causes of increasing incidence of MA are discussed. Observations on other clinical features like neurocognitive dysfunction, associated hyperhomocysteinemeia and occurrence of tremors and thrombocytosis during treatment are highlighted. PMID:20589460

Chandra, Jagdish

2010-07-01

284

Signal focusing through active transport  

E-print Network

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

Godec, Aljaz

2015-01-01

285

Rotating Apparatus for Isoelectric Focusing  

NASA Technical Reports Server (NTRS)

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

Bier, M.

1986-01-01

286

Hormone Purification by Isoelectric Focusing  

NASA Technical Reports Server (NTRS)

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

Bier, M.

1985-01-01

287

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

288

Non-focusing active warhead  

DOEpatents

A non-nuclear, non-focusing, active warhead that comprises a high explosive charge contained within a casing of reactive metal is disclosed. When the high explosive is detonated, the reactive metal is dispersed and reacts with the air, which significantly increases the explosive yield of the warhead. The active warhead produces therefore much higher blast effects with significantly reduced weight compared to conventional munitions. The warhead is highly effective against such targets as aircraft which typically have thin fuselages, for example. The explosiveness of this warhead can be enhanced further by elevating the temperature and therefore the reactivity of the reactive metal before or during the explosion. New methods of enhancing the reactivity of the metal are also taught. 4 figs.

Hornig, H.C.

1998-12-22

289

Non-focusing active warhead  

DOEpatents

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

290

Clinical focus: infections in pregnancy.  

PubMed

Pregnant women are particularly susceptible to a number of infectious diseases, such as influenza, hepatitis E, malaria, and tuberculosis. The management of many other infections-including urinary tract infections, human immunodeficiency virus, and sexually transmitted diseases-is also made more complex by pregnancy; even if some infections do not pose a great risk to the expectant mother, they can impact fetal and neonatal development, thus posing a treatment challenge to physicians. By focusing on the most important diseases that physicians may encounter in pregnant patients, this review outlines the challenges associated with managing important infectious diseases in the pregnant population and references the most recent evidence and international treatment guidelines. PMID:24769790

Adler, Hugh; Lambert, John S

2014-04-01

291

Tank Focus Area pretreatment activities  

SciTech Connect

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

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

1997-03-01

292

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

PubMed Central

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

2014-01-01

293

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)

2003-04-08

294

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

SciTech Connect

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

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

2014-06-15

295

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

296

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

297

Knowledge focus via software agents  

NASA Astrophysics Data System (ADS)

The essence of military Command and Control (C2) is making knowledge intensive decisions in a limited amount of time using uncertain, incorrect, or outdated information. It is essential to provide tools to decision-makers that provide: * Management of friendly forces by treating the "friendly resources as a system". * Rapid assessment of effects of military actions againt the "enemy as a system". * Assessment of how an enemy should, can, and could react to friendly military activities. Software agents in the form of mission agents, target agents, maintenance agents, and logistics agents can meet this information challenge. The role of each agent is to know all the details about its assigned mission, target, maintenance, or logistics entity. The Mission Agent would fight for mission resources based on the mission priority and analyze the effect that a proposed mission's results would have on the enemy. The Target Agent (TA) communicates with other targets to determine its role in the system of targets. A system of TAs would be able to inform a planner or analyst of the status of a system of targets, the effect of that status, adn the effect of attacks on that system. The system of TAs would also be able to analyze possible enemy reactions to attack by determining ways to minimize the effect of attack, such as rerouting traffic or using deception. The Maintenance Agent would scheudle maintenance events and notify the maintenance unit. The Logistics Agent would manage shipment and delivery of supplies to maintain appropriate levels of weapons, fuel and spare parts. The central idea underlying this case of software agents is knowledge focus. Software agents are createad automatically to focus their attention on individual real-world entities (e.g., missions, targets) and view the world from that entities perspective. The agent autonomously monitors the entity, identifies problems/opportunities, formulates solutions, and informs the decision-maker. The agent must be able to communicate to receive and disseminate information and provide the decision-maker with assistance via focused knowledge. THe agent must also be able to monitor the state of its own environment and make decisions necessary to carry out its delegated tasks. Agents bring three elements to the C2 domain that offer to improve decision-making. First, they provide higher-quality feedback and provide it more often. In doing so, the feedback loop becomes nearly continuous, reducing or eliminating delays in situation updates to decision-makers. Working with the most current information possible improves the control process, thus enabling effects based operations. Second, the agents accept delegation of actions and perform those actions following an established process. Agents' consistent actions reduce the variability of human input and stabilize the control process. Third, through the delegation of actions, agents ensure 100 percent consideration of plan details.

Henager, Donald E.

2001-09-01

298

FOCUS GROUPS A GUIDE TO LEARNING  

E-print Network

are also not appropriate for "go/no go" decisions or making statistical projections. Focus groups are ideal efforts, are called "focus groups". Focus groups are used increasingly in higher education as a form communication which is at the core of any great organization. Definition The focus group consists of six

Shapiro, Vadim

299

An occlusion insensitive adaptive focus measurement method.  

PubMed

This paper proposes a new focus measurement method for Depth From Focus to recover depth of scenes. The method employs an all-focused image of the scene to address the focus measure ambiguity problem of the existing focus measures in the presence of occlusions. Depth discontinuities are handled effectively by using adaptively shaped and weighted support windows. The size of the support window can be increased conveniently for more robust depth estimation without introducing any window size related Depth From Focus problems. The experiments on the real and synthetically refocused images show that the introduced focus measurement method works effectively and efficiently in real world applications. PMID:20588555

Aydin, Tarkan; Akgul, Yusuf S

2010-06-21

300

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

301

Findings: LANL outsourcing focus groups  

SciTech Connect

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

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

1996-12-31

302

Prime Focus Spectrograph - Subaru's future -  

E-print Network

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

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

2012-01-01

303

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

304

Focused electron beam induced deposition: A perspective  

PubMed Central

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

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

2012-01-01

305

Ultrasound-mediated Optical Imaging and Focusing in Scattering Media  

NASA Astrophysics Data System (ADS)

Because of its non-ionizing and molecular sensing nature, light has been an attractive tool in biomedicine. Scanning an optical focus allows not only high-resolution imaging but also manipulation and therapy. However, due to multiple photon scattering events, conventional optical focusing using an ordinary lens is limited to shallow depths of one transport mean free path (lt'), which corresponds to approximately 1 mm in human tissue. To overcome this limitation, ultrasonic modulation (or encoding ) of diffuse light inside scattering media has enabled us to develop both deep-tissue optical imaging and focusing techniques, namely, ultrasound-modulated optical tomography (UOT) and time-reversed ultrasonically encoded (TRUE) optical focusing. While UOT measures the power of the encoded light to obtain an image, TRUE focusing generates a time-reversed (or phase-conjugated) copy of the encoded light, using a phase-conjugate mirror to focus light inside scattering media beyond 1 lt'. However, despite extensive progress in both UOT and TRUE focusing, the low signal-to-noise ratio in encoded-light detection remains a challenge to meeting both the speed and depth requirements for in vivo applications. This dissertation describes technological advancements of both UOT and TRUE focusing, in terms of their signal detection sensitivities, operational depths, and operational speeds. The first part of this dissertation describes sensitivity improvements of encoded-light detection in UOT, achieved by using a large area (˜5 cm x 5 cm) photorefractive polymer. The photorefractive polymer allowed us to improve the detection etendue by more than 10 times that of previous detection schemes. It has enabled us to resolve absorbing objects embedded inside diffused media thicker than 80 lt', using moderate light power and short ultrasound pulses. The second part of this dissertation describes energy enhancement and fluorescent excitation using TRUE focusing in turbid media, using photorefractive materials as the phase-conjugate mirrors. By using a large-area photorefractive polymer as the phase-conjugate mirror, we boosted the focused optical energy by ~40 times over the output of a previously used photorefractive Bi 12SiO20 crystal. Furthermore, using both a photorefractive polymer and a Bi12SiO20 crystal as the phase-conjugate mirrors, we show direct visualization and dynamic control of TRUE focus, and demonstrate fluorescence imaging in a thick turbid medium. The last part of this dissertation describes improvements in the scanning speed of a TRUE focus, using digital phase-conjugate mirrors in both transmission and reflection modes. By employing a multiplex recording of ultrasonically encoded wavefronts in transmission mode, we have accelerated the generation of multiple TRUE foci, using frequency sweeping of both ultrasound and light. With this technique, we obtained a 2-D image of a fluorescent target centered inside a turbid sample having a thickness of 2.4 lt'. Also, by gradually moving the focal position in reflection mode, we show that the TRUE focal intensity is improved, and can be continuously scanned to image fluorescent targets in a shorter time.

Suzuki, Yuta

306

Molecular collisions coming into focus.  

PubMed

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

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

2014-08-14

307

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

308

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

309

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 G?i, G?s, G?q, G?12, and G?13 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 ?-catenin stability and activation of ?-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)

2003-06-10

310

Protein detection Proteomics  

E-print Network

Keywords Protein detection Proteomics Peptide Synthesis Alzheimer´s Disease Huntington´s Disease » Dr. Thole Zuchner The Ultrasensitive Protein Detec- tion Unit (USPDU) focuses on the development of new techniques, which allow the specific detec- tion of proteins in the zeptomole range (1021 mole

Schüler, Axel

311

WIMP direct detection overview  

E-print Network

This review on weakly interacting massive particle (WIMP) dark matter direct detection focuses on experimental approaches and the corresponding physics basics. The presentation is intended to provide a quick and concise introduction for non-specialists to this fast evolving topic of astroparticle physics.

Y. Ramachers

2002-11-22

312

AXAF VETA-I mirror ring focus measurements  

NASA Technical Reports Server (NTRS)

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

Tananbaum, H. D.; Zhao, P.

1994-01-01

313

The MINDS - Minnesota Intrusion Detection System  

Microsoft Academic Search

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

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

314

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

315

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.

316

Auto-focusing method for remote gaze tracking camera  

NASA Astrophysics Data System (ADS)

Gaze tracking determines what a user is looking at; the key challenge is to obtain well-focused eye images. This is not easy because the human eye is very small, whereas the required resolution of the image should be large enough for accurate detection of the pupil center. In addition, capturing a user's eye image by a remote gaze tracking system within a large working volume at a long Z distance requires a panning/tilting mechanism with a zoom lens, which makes it more difficult to acquire focused eye images. To solve this problem, a new auto-focusing method for remote gaze tracking is proposed. The proposed approach is novel in the following four ways: First, it is the first research on an auto-focusing method for a remote gaze tracking system. Second by using user-dependent calibration at initial stage, the weakness of the previous methods that use facial width in captured image to estimate Z distance between a user and camera, wherein each person has the individual variation of facial width, is solved. Third, the parameters of the modeled formula for estimating the Z distance are adaptively updated using the least squares regression method. Therefore, the focus becomes more accurate over time. Fourth, the relationship between the parameters and the face width is fitted locally according to the Z distance instead of by global fitting, which can enhance the accuracy of Z distance estimation. The results of an experiment with 10,000 images of 10 persons showed that the mean absolute error between the ground-truth Z distance measured by a Polhemus Patriot device and that estimated by the proposed method was 4.84 cm. A total of 95.61% of the images obtained by the proposed method were focused and could be used for gaze detection.

Lee, Won Oh; Lee, Hyeon Chang; Cho, Chul Woo; Gwon, Su Yeong; Park, Kang Ryoung; Lee, Heekyung; Cha, Jihun

2012-06-01

317

Parent Leadership and Family Involvement (Special Focus).  

ERIC Educational Resources Information Center

This "Special Focus" issue of "America's Family Support Magazine," focuses on parent leadership and family involvement. Articles pertaining to this focus include: (1) "Forging Equal Partnerships" (Ahsan); (2) "Who Best Represents the Voice of Parents?" (Foster); (3) "Parent Leadership Training Programs" (Baum); (4) "Parents as Family Support…

Wolf, Kathy Goetz, Ed.; Lalley, Jacqueline, Ed.

1999-01-01

318

Techniques For Focusing In Zone Electrophoresis  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

319

The Development of Change Detection  

ERIC Educational Resources Information Center

Changes to a scene often go unnoticed if the objects of the change are unattended, making change detection an index of where attention is focused during scene perception. We measured change detection in school-age children and young adults by repeatedly alternating two versions of an image. To provide an age-fair assessment we used a bimanual…

Shore, David I.; Burack, Jacob A.; Miller, Danny; Joseph, Shari; Enns, James T.

2006-01-01

320

Acoustic focusing by metal circular ring structure  

NASA Astrophysics Data System (ADS)

We report an exotic acoustic focusing effect through a simple brass circular ring structure immersed in water. The acoustic waves can be focused on a prefect point at the centre of the ring structure. This exotic acoustic focusing phenomenon arises from the intrinsic modes in the ring structure at some special eigenfrequencies, which is essentially distinct from the previous studies originating from the negative refraction. The focusing effect is closely related to the size and shape of the ring structure. Interesting applications of the focusing mechanism in black box detectors in the sea and medical ultrasound treatment are further discussed.

Xia, Jian-Ping; Sun, Hong-Xiang

2015-02-01

321

Quantitative results from the focusing schlieren technique  

NASA Technical Reports Server (NTRS)

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

Cook, S. P.; Chokani, Ndaona

1993-01-01

322

Simfit and Focus Diversity: methods for determining the focus of the SIRTF telescope in space without a focus slew  

NASA Astrophysics Data System (ADS)

Because of concern over possible failure of the SIRTF cryogenic focus mechanism in space, the SIRTF Project Office has directed that the focus should be set before launch so that the telescope arrives in orbit as close to optimum focus as possible. Then focus evaluation and determination of any required focus change to achieve best focus must be carried out without the conventional approach of a focus slew. For these tasks we have created two methods: Simfit and Focus Diversity. Simfit is a procedure for comparing an observed stellar image with a family of simulated point-source images with a range of focus settings. With a sufficiently accurate as-built telescope model for creating the simulated images, the focus offset and direction can be accurately and unambiguously determined because of the change in image appearance with defocus. Focus diversity takes advantage of the variation of best-focus setting over the instrument's focal plane due to focal plane curvature and tilt and offsets between different instrument channels. By plotting an image quality parameter, such as noise-pixels, for observed stars at several positions on the focal plane versus a defocus variable, the focus error and direction can be determined. We have developed an efficient program for carrying out these procedures. The validity of this program has been successfully confirmed using point-source images observed with three bands of the IRAC camera during a double-pass optical test of SIRTF in a Ball Aerospace cryogenic test chamber. The two procedures are described and are illustrated with these results

Hoffmann, William F.; Hora, Joseph L.; Mentzell, J. Eric; Marx, Catherine; Eisenhardt, Peter

2003-03-01

323

Tests of a proximity focusing RICH with aerogel as radiator  

E-print Network

Using aerogel as radiator and multianode PMTs for photon detection, a proximity focusing Cherenkov ring imaging detector has been constructed and tested in the KEK $\\pi$2 beam. The aim is to experimentally study the basic parameters such as resolution of the single photon Cherenkov angle and number of detected photons per ring. The resolution obtained is well approximated by estimates of contributions from pixel size and emission point uncertainty. The number of detected photons per Cherenkov ring is in good agreement with estimates based on aerogel and detector characteristics. The values obtained turn out to be rather low, mainly due to Rayleigh scattering and to the relatively large dead space between the photocathodes. A light collection system or a higher fraction of the photomultiplier active area, together with better quality aerogels are expected to improve the situation. The reduction of Cherenkov yield, for charged particle impact in the vicinity of the aerogel tile side wall, has also been measured.

I. Adachi; I. Bizjak; A. Gorisek; T. Iijima; M. Iwamoto; S. Korpar; P. Krizan; R. Pestotnik; M. Staric; A. Stanovnik; T. Sumiyoshi; K. Suzuki; T. Tabata

2003-03-25

324

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

E-print Network

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

325

Approximation to the Fisher-Rao Metric for the Focus of Expansion  

E-print Network

Approximation to the Fisher-Rao Metric for the Focus of Expansion S.J. Maybank 10 April 2007 School@dcs.bbk.ac.uk Abstract. The Fisher-Rao metric for the focus of expansion is approximated, under the assumption in turn to see if it is supported by the image correspondences. Keywords: false detection; Fisher-Rao

Maybank, Steve

326

Focus and dose characterization of immersion photoclusters  

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

327

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

PubMed

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

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

2014-01-01

328

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

PubMed Central

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

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

2014-01-01

329

Focus-of-attention for human activity recognition from UAVs  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

330

Using Focus Group Research in Public Relations.  

ERIC Educational Resources Information Center

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

Grunig, Larissa A.

1990-01-01

331

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

332

Focused tsunami waves BY M. V. BERRY  

E-print Network

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

Berry, Michael Victor

333

Peer Led Focus Groups and Young People  

ERIC Educational Resources Information Center

Peer led focus groups, a qualitative social science research method, and their use with young people are examined. The paper outlines three developments that have contributed to their emergence, namely: traditional focus groups, peer education and participatory research. Drawing on a study in progress, the advantages and challenges associated with…

Murray, Cathy

2006-01-01

334

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

335

Identifying Information Focuses in Listening Comprehension  

ERIC Educational Resources Information Center

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

Zhang, Hong-yan

2011-01-01

336

A line focus segmented mirror concentrator  

Microsoft Academic Search

A solar concentrator system is described which is based on the use of a long array of east-west mounted focusing reflectors. Each of the reflective segments projects a line image of the sun into the entrance aperture of a stationary receiver through which a working fluid flows. Typically, ten segments in parallel are initially aligned to focus on the same

D. E. Anderson; R. A. Stickley

1977-01-01

337

How I Learned to Conduct Focus Groups  

ERIC Educational Resources Information Center

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

Del Rio-Roberts, Maribel

2011-01-01

338

Focus on Life Science in Lbeck  

E-print Network

Focus on Life Science in Lübeck #12;#12;What distinguishes us from others is that although we and engineering. The common element among these is their focus on life sciences, which is also mirrored by our, computational life science, molecular life science and medical engineering science. We initiated a master

Lübeck, Universität zu

339

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

340

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

341

Laser-induced focused ultrasound for nondestructive testing and evaluation  

NASA Astrophysics Data System (ADS)

Focused ultrasound pulses generated by photoacoustic transformation at a metal surface immersed in water possess a pronounced compression phase on the nanosecond time scale. For 8 ns laser pump pulses, the spectrum of the initially generated ultrasonic pulse covered a frequency range between 0.1 and 150 MHz. A concave spherical geometry of the light-absorbing metal surface can be used to achieve focusing. In the present experiments a conical ultrasound beam was directed at a solid glass plate or silicon wafer, where the tilt of the normal of the metal mirror defined the efficiency of mode conversion at the water-solid interface. Depending on the configuration, focused bulk waves as well as Rayleigh and Lamb waves could be launched in the sample with this setup. The laser probe-beam-deflection method was employed for local detection of elastic disturbances at the sample surface. Due to the nonlinear elastic response of water and harmonics generation, frequencies >100 MHz were realized, despite a strong attenuation in this frequency range. Gradual increase of the laser power density from 5 to 14 MW/cm2 led to shock formation in the compressive pressure pulse in water and shortening of the Rayleigh pulse induced at the surface of the glass plate. The observed transient surface profiles were highly sensitive to nearby mechanical discontinuities such as a microcrack in glass or an edge discontinuity in silicon. Therefore, laser-induced focused ultrasound seems to be a very promising method of accomplishing diverse tasks of nondestructive evaluation.

Kozhushko, Victor V.; Hess, Peter

2008-06-01

342

Viscoelastic effects on electrokinetic particle focusing in a constricted microchannel.  

PubMed

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

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

2015-01-01

343

Fraud Detection in Healthcare  

SciTech Connect

We discuss the problem of fraud detection in healthcare in this chapter. Given the recent scrutiny of the ineciencies in the US healthcare system, identifying fraud has been on the forefront of the eorts towards reducing the healthcare costs. In this chapter we will focus on understanding the issue of healthcare fraud in detail, and review methods that have been proposed in the literature to combat this issue using data driven approach.

Chandola, Varun [ORNL; Schryver, Jack C [ORNL; Sukumar, Sreenivas R [ORNL

2015-01-01

344

Design of micromachined self-focusing piezoelectric composite ultrasound transducer.  

PubMed

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

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

2014-08-01

345

Ovulation Detection  

MedlinePLUS

... URL www.asrm.org PATIENT’S FACT SHEET Ovulation Detection Ovulation, the release of an egg from its ... their physicians to decide which method of ovulation detection is best for them. If these tests indicate ...

346

Superpixel Analysis for Object Detection and Tracking  

E-print Network

Superpixel Analysis for Object Detection and Tracking with Application to UAV Imagery Christopher (under 500 m). There are many possible image processing tasks for UAVs; we focus on horizon detection introduce a framework for object detection and tracking in video of natural outdoor scenes based on fast per

Rasmussen, Christopher

347

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

348

Focusing on moving targets through scattering samples  

PubMed Central

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

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

2014-01-01

349

Deep-Focusing Time-Distance Helioseismology  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

350

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

351

Aerodynamic Focusing Of High-Density Aerosols  

SciTech Connect

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

Ruiz, D. E.; Fisch, Nathaniel

2014-02-24

352

Self-focusing in multicore fibers.  

PubMed

Self-focusing is the ultimate power limit of single mode fiber amplifiers. As fiber technology is approaching this limit, ways to mitigate self-focusing are becoming more and more important. Here we show a theoretical analysis of this limitation in coupled multicore fibers. Significant scaling of the self-focusing limit is possible even for coupled multicore fibers if the out-of-phase mode is chosen. On the other hand the in-phase mode can - depending on the coupling strength - be prone to instabilities. PMID:25836111

Tünnermann, Henrik; Shirakawa, Akira

2015-02-01

353

Line-focus concentrating collector program  

NASA Astrophysics Data System (ADS)

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

Dugan, V. L.

1980-05-01

354

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

355

A sharp-focusing schlieren optical deflectometer  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

356

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

357

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

358

Focusing on ADHD - Attention Deficit Hyperactivity Disorder  

MedlinePLUS

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

359

Focus Issue: A Cell's Sense of Direction  

NSDL National Science Digital Library

The process by which cells orient their movement according to external gradients plays important roles in physiological and pathological processes. This Focus Issue of Science Signaling highlights the interplay between molecules, signaling pathways, and mechanisms that enable directional movement.

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

2012-02-28

360

Prediction of sonic boom at a focus  

NASA Technical Reports Server (NTRS)

The behavior of sonic boom at a focus has been reviewed for the purpose of extending present sonic boom computational methods to include focal zones. The geometry of a focal zone - whether a smooth caustic, a cusped caustic, or a perfect focus to a point - determines the character of focused signatures. The seeming contradiction of various experimental data can be resolved by noting these differences. A ray acoustic analysis has been developed for quantitative determination of caustic geometry. The only reliable theory presently available for signatures at a focus is for a smooth caustic. There has been some controversy between theoretical and experimental values of a constant in the scaling law for this case. It has been found that this discrepancy can be resolved by accounting for the finite thickness of real sonic boom shock waves. These findings have been incorporated into an existing sonic boom computer program.

Plotkin, K. J.; Cantril, J. M.

1976-01-01

361

Micro free-flow isoelectric focusing  

E-print Network

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

Albrecht, Jacob William

2008-01-01

362

Social Work Intervention Focused on Transitions  

ClinicalTrials.gov

Study Focus: 30-day Rehospitalizations Among At-risk Older Adults Randomized to a Social Work-driven Care Transitions Intervention; Heart Disease; Diabetes; Hypertension; Cancer; Depression; Asthma; Chronic Heart Failure; Chronic Obstructive Pulmonary Disease; Stroke

2014-09-04

363

Determination of Spitzer Space Telescope focus from IRAC images without a focus slew  

NASA Astrophysics Data System (ADS)

Prior to launch, the Spitzer Space Telescope (SST) secondary focus mechanism was set to a predicted desired in-orbit focus value. This predicted setting, determined from double-pass cold chamber measurements and calculated ground-to-orbit corrections, had an uncertainty greater than the required in-orbit focus accuracy. Because of concern about the potential for failure in a cryogenic mechanism affecting all Spitzer instruments, it was required that any focus correction be made in a set of moves directly from the initial to the desired setting. The task of determining the required focus moves fell to IRAC (Infrared Array Camera), the instrument most affected by and sensitive to defocus. To determine the focus directly from examining images at a fixed focus, we developed two methods, "Simfit" and "Focus Diversity" (W. F. Hoffmann, et. al.1). Simfit finds the focus by obtaining the best match between observed images and families of simulated images at a range of focus settings. Focus Diversity utilizes the focal plane curvature to find the best fit of the varied image blur over the focal plane to a model defocus curve. Observations of a single star at many field locations in each of the four IRAC bands were analyzed before and during the refocus activity. The resulting refocus moves brought the focus close to the specified requirement of within 0.3 mm from the desired IRAC optimum focus. This is less than a "Diffraction Focus Unit" (?x(f/2)) of 0.52 mm at the SST focus at the shortest IRAC band (3.58 microns). The improvement in focus is apparent in both the appearance and the calculated noise-pixels of star images.

Hoffmann, William F.; Hora, Joseph L.; Mentzell, John E.; Marx, Catherine T.; Eisenhardt, Peter R.; Carey, Sean J.; Megeath, S. T.; Schwenker, John P.

2004-10-01

364

Two-axis sagittal focusing monochromator  

DOEpatents

An x-ray focusing device and method for adjustably focusing x-rays in two orthogonal directions simultaneously. The device and method can be operated remotely using two pairs of orthogonal benders mounted on a rigid, open frame such that x-rays may pass through the opening in the frame. The added x-ray flux allows significantly higher brightness from the same x-ray source.

Haas, Edwin G; Stelmach, Christopher; Zhong, Zhong

2014-05-13

365

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

366

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

367

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

PubMed Central

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

Vykhodtseva, Natalia; McDannold, Nathan; Hynynen, Kullervo

2008-01-01

368

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

369

Determination of the SIRTF Focus from IRAC Images without a Focus Slew  

NASA Astrophysics Data System (ADS)

Prior to launch, the SIRTF secondary focus mechanism was set to a predicted desired in-orbit focus value. This predicted setting, determined from double-pass cold chamber measurements and calculated ground-to-orbit corrections, had an uncertainty greater than the required on-orbit focus accuracy. Because of concern about the potential for failure in a cryogenic mechanism affecting all SIRTF instruments, it was required that any focus correction be made in a set of moves directly from the initial to the desired setting. The task of determining the required focus moves fell to IRAC, the instrument most affected by and sensitive to defocus. To determine the focus directly from examining images at a fixed focus, we developed two methods, "Simfit" and "Focus Diversity" (Hoffmann W. F., et. al., 2003, SPIE, 4850, 428). Simfit finds the focus by obtaining the best match between observed images and families of simulated images at a range of focus settings. Focus Diversity utilizes the focal plane curvature to find the best fit of the varied image blur over the focal plane to a model defocus curve. Observations of a single star at many field locations in each of the four IRAC channels were analyzed before and during the refocus activity. The resulting refocus moves brought the focus to well within the specified requirement of 0.3 mm from the desired IRAC optimum focus. This is substantially less than a "Diffraction Focus Unit" (wavelength times focal ratio squared) of 0.48 mm at the shortest IRAC band (3.6 microns). The improvement in focus is apparent in both the appearance and the calculated noise-pixels of star images.

Hoffmann, W. F.; Hora, J. L.; Mentzell, J. E.; Marx, C. T.; Eisenhardt, P. R.; Carey, S. J.; Megeath, S. T.

2003-12-01

370

Focusing hard x rays to nanometer dimensions by adiabatically focusing lenses.  

PubMed

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. Bergemann, Phys. Rev. Lett.912003204801]. PMID:15783651

Schroer, C G; Lengeler, B

2005-02-11

371

Focus and alignment using out-of-focus stellar images at the Dark Energy Camera  

NASA Astrophysics Data System (ADS)

The focus and alignment system of the prime focus Dark Energy Camera (DECam), for the Dark Energy Survey at the CTIO 4 meter Blanco telescope, is described. DECam includes eight 2K by 2K CCDs placed 1.5mm extra- and intra-focally for active control of focus and alignment, as well as for wavefront measurement. We describe an algorithm for out-of-focus star (donut) image analysis and present results on the use of donuts for focus and alignment. Results will be presented for both simulated DECam images and for images taken at the Blanco 4 meter with the current MosaicII camera.

Roodman, Aaron

2010-07-01

372

Topicality and Impact in Social Media: Diverse Messages, Focused Messengers  

PubMed Central

We have a limited understanding of the factors that make people influential and topics popular in social media. Are users who comment on a variety of matters more likely to achieve high influence than those who stay focused? Do general subjects tend to be more popular than specific ones? Questions like these demand a way to detect the topics hidden behind messages associated with an individual or a keyword, and a gauge of similarity among these topics. Here we develop such an approach to identify clusters of similar hashtags in Twitter by detecting communities in the hashtag co-occurrence network. Then the topical diversity of a user’s interests is quantified by the entropy of her hashtags across different topic clusters. A similar measure is applied to hashtags, based on co-occurring tags. We find that high topical diversity of early adopters or co-occurring tags implies high future popularity of hashtags. In contrast, low diversity helps an individual accumulate social influence. In short, diverse messages and focused messengers are more likely to gain impact. PMID:25710685

Weng, Lilian; Menczer, Filippo

2015-01-01

373

Topicality and impact in social media: diverse messages, focused messengers.  

PubMed

We have a limited understanding of the factors that make people influential and topics popular in social media. Are users who comment on a variety of matters more likely to achieve high influence than those who stay focused? Do general subjects tend to be more popular than specific ones? Questions like these demand a way to detect the topics hidden behind messages associated with an individual or a keyword, and a gauge of similarity among these topics. Here we develop such an approach to identify clusters of similar hashtags in Twitter by detecting communities in the hashtag co-occurrence network. Then the topical diversity of a user's interests is quantified by the entropy of her hashtags across different topic clusters. A similar measure is applied to hashtags, based on co-occurring tags. We find that high topical diversity of early adopters or co-occurring tags implies high future popularity of hashtags. In contrast, low diversity helps an individual accumulate social influence. In short, diverse messages and focused messengers are more likely to gain impact. PMID:25710685

Weng, Lilian; Menczer, Filippo

2015-01-01

374

Topicality and Social Impact: Diverse Messages but Focused Messengers  

E-print Network

Are users who comment on a variety of matters more likely to achieve high influence than those who delve into one focused field? Do general Twitter hashtags, such as #lol, tend to be more popular than novel ones, such as #instantlyinlove? Questions like these demand a way to detect topics hidden behind messages associated with an individual or a hashtag, and a gauge of similarity among these topics. Here we develop such an approach to identify clusters of similar hashtags by detecting communities in the hashtag co-occurrence network. Then the topical diversity of a user's interests is quantified by the entropy of her hashtags across different topic clusters. A similar measure is applied to hashtags, based on co-occurring tags. We find that high topical diversity of early adopters or co-occurring tags implies high future popularity of hashtags. In contrast, low diversity helps an individual accumulate social influence. In short, diverse messages and focused messengers are more likely to gain impact.

Weng, Lilian

2014-01-01

375

MUSIC algorithms for rebar detection  

NASA Astrophysics Data System (ADS)

The MUSIC (MUltiple SIgnal Classification) algorithm is employed to detect and localize an unknown number of scattering objects which are small in size as compared to the wavelength. The ensemble of objects to be detected consists of both strong and weak scatterers. This represents a scattering environment challenging for detection purposes as strong scatterers tend to mask the weak ones. Consequently, the detection of more weakly scattering objects is not always guaranteed and can be completely impaired when the noise corrupting data is of a relatively high level. To overcome this drawback, here a new technique is proposed, starting from the idea of applying a two-stage MUSIC algorithm. In the first stage strong scatterers are detected. Then, information concerning their number and location is employed in the second stage focusing only on the weak scatterers. The role of an adequate scattering model is emphasized to improve drastically detection performance in realistic scenarios.

Solimene, Raffaele; Leone, Giovanni; Dell'Aversano, Angela

2013-12-01

376

Dialogue Sequence Detection in Movies  

Microsoft Academic Search

\\u000a Dialogue sequences constitute an important part of any movie or television program and their successful detection is an essential\\u000a step in any movie summarisation\\/indexing system. The focus of this paper is to detect sequences of dialogue, rather than complete scenes. We argue that these shorter sequences are more desirable as retrieval units than\\u000a temporally long scenes. This paper combines various

Bart Lehane; Noel E. O'connor; Noel Murphy

2005-01-01

377

Measurement of focused ultrasonic fields using a scanning laser vibrometer.  

PubMed

With the development of optical techniques, scanning laser vibrometers have been applied successfully in measuring particle velocities and distributions in ultrasonic fields. In this paper, to develop the optical interferometry in measuring focused fields with small amplitude, the "effective" refractive index used for plane waves and extended for spherical waves is presented, the piezo-optic effect as a function of the incident angle of the laser beam is simulated, and the ultrasonic field produced by a concave spherical transducer is calculated numerically around its focal region. To verify the feasibility of the optical method in detecting focused ultrasonic fields, a measurement system was set up that utilized both a scanning laser vibrometer and a membrane hydrophone. Measurements were made in different zones of a focusing transducer, and good results were acquired from the optical interferometry in regions where acoustic waves travel in plane form or spherical form. The data obtained from the optical method are used to reconstruct acoustic fields, and it is found that the focal plane, the maximum pressure, and the beamwidth of the transducer can be forecasted accurately. PMID:17550161

Wang, Yuebing; Tyrer, John; Zhihong, Ping; Shiquan, Wang

2007-05-01

378

Focused ultrasound guided relocation of kidney stones  

PubMed Central

Purpose: Complete removal of all fragments is the goal of any intervention for urinary stones. This is more important in lower pole stones where gravity and spatial orientation of lower pole infundibulum may hinder spontaneous passage of fragments. Various adjuvant therapies (inversion, diuresis, percussion, oral citrate, etc.) are described to enhance stone-free rate but are not widely accepted. Focused ultrasound-guided relocation of fragments is a recently described technique aimed at improving results of intervention for stone disease. Purpose of this review is to discuss development of this technology and its potential clinical applications. Materials and Methods: Pubmed search was made using key words “Focused ultrasound” and “kidney stone”. All English language articles were reviewed by title. Relevant studies describing development and application of focused ultrasound in renal stones were selected for review. Results: Focused ultrasound has proven its efficacy in successfully relocating up to 8 mm stone fragments in vitro and in pigs. Relocation is independent of stone composition. The latest model allows imaging and therapy with a single handheld probe facilitating its use by single operator. The acoustic energy delivered by the new prototype is even less than that used for extracorporeal shock wave lithotripsy. Therapeutic exposure has not caused thermal injury in pig kidneys. Conclusion: Focused ultrasound-guided relocation of stones is feasible. Though it is safe in application in pigs, technology is awaiting approval for clinical testing in human beings. This technology has many potential clinical applications in the management of stone disease. PMID:25624572

Abrol, Nitin; Kekre, Nitin S.

2015-01-01

379

An Experimental Near-Field Focusing Plate  

NASA Astrophysics Data System (ADS)

Using a patterned grating-like surface, which we refer to as a near-field plate [1], we experimentally demonstrate focusing of 1.027 GHz radiation well beyond the diffraction limit. A near-field plate is a finely structured surface that acts as a modulated surface reactance [2]. Its ability to provide subwavelength resolution relies on the strong near-field coupling that exists between the reactive surface elements of the plate. This coupling sets up a highly oscillatory electromagnetic field at the plate surface which can focus in the near-field. The plate consists of an array of interdigitated capacitors printed on an electrically thin dielectric substrate. It focuses microwaves emanating from an S-polarized cylindrical source (vertical line current) to a focus with a null-to-null beamwidth equal to one-tenth of the wavelength. Passive surfaces that can focus electromagnetic energy to extreme subwavelength dimensions offer an advantage with respect to slabs in that they obviate the need for the 3D fabrication techniques. Applications in antennas, beam-shaping devices, wireless non-radiative power transfer systems, microscopy and lithography will be discussed. [1] R. Merlin, Science 317, 927 (2007). [2] A. Grbic and R. Merlin, arXiv:0708.0049.

Grbic, A.; Jiang, L.; Merlin, R.

2008-03-01

380

Efficient OPC model generation and verification for focus variation  

NASA Astrophysics Data System (ADS)

As the k1 factor of lithography process goes lower, model-based optical proximity correction (OPC) has become the most important step of post-tape-out data preparation for critical mask levels. To apply model-based OPC, a lithographic model with optical and resist parameters usually generated by a regression is required. It takes significant turn-around-time (TAT) to obtain the OPC model, normally more than 1 day per mask level. In this paper, we present an automatic and effective OPC model extraction method using the adaptive simulated annealing (ASA) algorithm. By applying this algorithm to extract the optimal model parameter values, we reduced the model parameter fitting time to less than 1 hour. We confirm the reliability and accuracy of the model generated by this method. With this newly developed automatic modeling method, we present a methodology to detect the critical failure on the wafer effectively that can occur by the focus variation during the lithography process. Generally, we sample only one set of measurement CD data taken under a controlled process condition with the best focus. Based on measurement data at the best focus, the in-house lithography simulator, FAITH TM, can generate simulated CD data for the multiple defocus levels without measurement data at the variable defocus levels. The multiple defocus models are built based on the simulated CD data and the automatic OPC modeling method makes the model buildings very fast. Finally, through the simulation of OPC result according to the multiple defocus models, we can verify or forecast the defocus effect before realistic patterning on wafers efficiently. We show the capability of weak point detection by this methodology on the 80nm DRAM devices with ArF photolithography.

Park, Yong-Hee; Ban, Yong-Chan; Hur, Duck-Hyung; Kim, Dong-Hyun; Hong, Ji-Suk; Yoo, Moon-Hyun; Kong, Jeong-Taek

2006-03-01

381

Remote Adjustable focus Raman Spectroscopy Probe  

SciTech Connect

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

382

Inertial focusing dynamics in spiral microchannels  

PubMed Central

This report details a comprehensive study of inertial focusing dynamics and particle behavior in low aspect ratio (h/w ? 1/1 to 1/8) spiral microchannels. A continuum of particle streak behavior is shown with longitudinal, cross-sectional, and velocity resolution, yielding a large analyzed parameter space. The dataset is then summarized and compared to prior results from both straight microchannels and other low aspect ratio spiral microchannel designs. Breakdown of focusing into a primary and secondary fluorescent streak is observed in the lowest aspect ratio channels at high average downstream velocities. Streak movement away from the theoretically predicted near inner wall equilibrium position towards the center of the channel at high average downstream velocities is also detailed as a precursor to breakdown. State diagrams detail the overall performance of each device including values of the required channel lengths and the range of velocities over which quality focusing can be achieved. PMID:22454556

Martel, Joseph M.; Toner, Mehmet

2012-01-01

383

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

384

Focused plasmonic trapping of metallic particles  

PubMed Central

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

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

2013-01-01

385

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

386

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

387

Planar microlens relay optics utilizing lateral focusing.  

PubMed

We have proposed a novel concept of planar microlens relay optics with the goal of realizing alignment-free and multifunctional integrated optical subsystems. Since the planar microlens is one of its key elements, its lateral focusing characteristics were examined. The measured focusing spot size was 3 microm x 7 microm, which is comparable with the core of single-mode optical fibers. By measuring the refractive-index distribution, we found that the planar microlens produced by the electromigration method has a desirable index distribution that resembles that of a Luneburg lens. Thus we conclude that planar microlens relay optics may be facilitated when the lateral focusing property of planar microlenses is used. PMID:20733703

Intani, D; Baba, T; Iga, K

1992-09-01

388

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

389

Measurements of the thermal focus of an experimental focused ultrasound thermotherapy system.  

PubMed

The thermal focus of an experimental thermotherapy equipment based on high energy focused ultrasound has been investigated. The in-house built equipment has a treatment head of seven separate focused transducers arranged in a semispherical fixture with a common focus at 100 mm from the transducer surfaces. Each transducer has a diameter of 50 mm and operates at 0.5 MHz. The ultrasound field of this seven-transducer arrangement, as well as of a single transducer of the same type as the ones in the arrangement, has been investigated in terms of temperature distribution evolved by absorption in castor oil. The results of the single transducer measurements show an ellipsoid-shaped focus displaced from the geometrical focus towards the transducer, whereas the measurements of the treatment head show a thermal focus which practically coincides with the geometrical one. Differences in location and shape of the thermal focuses depend on differences in the focusing action and the absorption in the media. Pilot investigations on tissue lesioning in vitro on pig muscle samples and in vivo on pig thigh were also carried out. Well discriminated local lesions with ellipsoid shape were obtained in the experiments in vitro and in vivo. Temperatures of up to 80 degrees C were measured in tissue at the focus in vitro. The results show that the equipment is well suited for thermotherapy applications. PMID:9690150

Barkman, C A; Kirkhorn, T; Almquist, L O; Holmer, N G

1998-01-01

390

Bat Detective  

NSDL National Science Digital Library

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

Zooniverse

2014-05-14

391

Detecting Collusion  

Microsoft Academic Search

Detection and deterrence of collusion are longstanding antitrust problems, made difficult because collusive arrangements are usually surreptitious. In this paper, I discuss factors that facilitate or inhibit collusive schemes, as well as circumstances where detection \\u000ais possible. I describe how industrial organization economists diagnose collusion (both explicit and tacit) among firms.

Robert H. Porter

2005-01-01

392

A comparison-based approach to mispronunciation detection  

E-print Network

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

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

2012-01-01

393

Gearbox Typical Failure Modes, Detection, and Mitigation Methods (Presentation)  

SciTech Connect

This presentation was given at the AWEA Operations & Maintenance and Safety Seminar and focused on what the typical gearbox failure modes are, how to detect them using detection techniques, and strategies that help mitigate these failures.

Sheng, S.

2014-01-01

394

Detection and localization of aerosol releases from sparse sensor measurements  

E-print Network

In this thesis we focus on addressing two aspects pertinent to biological release detection. The first is that of detecting and localizing an aerosolized particle release using a sparse array of sensors. The problem is ...

Fox, Emily Beth

2005-01-01

395

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

396

Aspherical lens shapes for focusing synchrotron beams.  

PubMed

Aspherical surfaces required for focusing collimated and divergent synchrotron beams using a single refractive element (lens) are reviewed. The Cartesian oval, a lens shape that produces perfect point-to-point focusing for monochromatic radiation, is studied in the context of X-ray beamlines. Optical surfaces that approximate ideal shapes are compared. Results are supported by ray-tracing simulations. Elliptical lenses, rather than parabolic, are preferred for nanofocusing X-rays because of the higher peak and lower tails in the intensity distribution. Cartesian ovals will improve the gain when using high-demagnification lenses of high numerical aperture. PMID:22514171

Sanchez del Rio, Manuel; Alianelli, Lucia

2012-05-01

397

Light focusing in the Anderson regime.  

PubMed

Anderson localization is a regime in which diffusion is inhibited and waves (also electromagnetic waves) get localized. Here we exploit adaptive optics to achieve focusing in disordered optical fibres in the Anderson regime. By wavefront shaping and optimization, we observe the generation of a propagation-invariant beam, where light is trapped transversally by disorder, and show that Anderson localizations can be also excited by extended speckled beams. We demonstrate that disordered fibres allow a more efficient focusing action with respect to standard fibres in a way independent of their length, because of the propagation-invariant features and cooperative action of transverse localizations. PMID:25072204

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

2014-01-01

398

Ion heating in a plasma focus  

NASA Technical Reports Server (NTRS)

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

Hohl, F.; Gary, S. P.

1974-01-01

399

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.

Joanne K. Olson

2008-12-01

400

Hormone purification by isoelectric focusing in space  

NASA Technical Reports Server (NTRS)

The performance of a ground-prototype of an apparatus for recycling isoelectric focusing was evaluated in an effort to provide technology for large scale purification of peptide hormones, proteins, and other biologicals. Special emphasis was given to the effects of gravity on the function of the apparatus and to the determination of potential advantages deriveable from its use in a microgravity environment. A theoretical model of isoelectric focusing sing chemically defined buffer systems for the establishment of the pH gradients was developed. The model was transformed to a form suitable for computer simulations and was used extensively for the design of experimental buffers.

Bier, M.

1982-01-01

401

Optimization of the NLC final focus system  

SciTech Connect

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

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

1995-06-01

402

Focusing Ultrasound with an Acoustic Metamaterial Network  

NASA Astrophysics Data System (ADS)

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

Zhang, Shu; Yin, Leilei; Fang, Nicholas

2009-05-01

403

The changing focus of marine mammal conservation.  

PubMed

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

Hofman, R J

1995-11-01

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

Optimal spatiotemporal focusing through complex scattering media.  

PubMed

We present an alternative approach for spatiotemporal focusing through complex scattering media by wave front shaping. Using a nonlinear feedback signal to shape the incident pulsed wave front, we show that the limit of a spatiotemporal matched filter can be achieved; i.e., the wave amplitude at the intended time and focus position is maximized for a given input energy. It is exactly what is also achieved with time reversal. Demonstrated with ultrasound experiments, our method is generally applicable to all types of waves. PMID:22400693

Aulbach, Jochen; Bretagne, Alice; Fink, Mathias; Tanter, Mickaël; Tourin, Arnaud

2012-01-01

406

Improved Large-Field Focusing Schlieren System  

NASA Technical Reports Server (NTRS)

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

Weinstein, Leonard M.

1993-01-01

407

Wide and narrow dual image guidance system for ground vehicle on fast focusing and stereo matching operation  

NASA Astrophysics Data System (ADS)

We have developed the wide and narrow dual image guidance system for ground vehicle on fast focusing and stereo matching operation. The fast focusing catches the distance information of outside world. The stereo matching operation on the focused two wide images finds the characteristic position to detect the fine distance information through the fast focusing using the narrow images due to the camera with the long focal length. Our fast focusing algorithm works precisely on the differential image such as the Daubechies wavelet transformed high pass image, the Roberts image, Prewitt image, Sobel image and the Laplacian image. After the stereo matching operation on the focused wide images, the two cameras serves the narrow image focusing operation. This procedure establishes the reliability of the detection of the object and gives the fine image information of the object. The pointing operation of the long focal length camera of the narrow image uses the related pixel address information due to the stereo matching and the 2 axes gimbal equipment of the precise resolution. We experimented the detection of the object by stereo matching and ranging the fine distance by narrow image focusing. The experiment gives the appropriate detection and fine pointing of the narrow image focusing to meet the guidance capability of the ground vehicle.

Akiyama, Akira; Kobayashi, Nobuaki; Mutoh, Eiichiro; Kumagai, Hideo; Ishii, Hiromitsu

2011-10-01

408

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

PubMed

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

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

2013-10-01

409

Consonant landmark detection for speech recognition  

E-print Network

This thesis focuses on the detection of abrupt acoustic discontinuities in the speech signal, which constitute landmarks for consonant sounds. Because a large amount of phonetic information is concentrated near acoustic ...

Park, Chi-youn, 1981-

2008-01-01

410

Crystal diffraction lens telescope for focusing nuclear gamma rays  

SciTech Connect

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

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

1996-08-01

411

Focus and alignment of the Dark Energy Camera using out-of-focus stars  

NASA Astrophysics Data System (ADS)

The active optics system of the Dark Energy Camera (DECam) at the CTIO 4 meter Blanco telescope, built for the Dark Energy Survey, uses out-of-focus stars (donuts) to determine the camera's focus and alignment, as well as provide a measure of the wavefront. In this paper, we describe the donut analysis algorithm and present results on focus, alignment, and wavefront from a donut campaign conducted at the Blanco from 2010 to 2012, using the previous wide-field camera.

Roodman, Aaron

2012-09-01

412

Exploring the Focus-morphology interface: Morpho-syntactic aspects of nonprosodic Focus  

E-print Network

Exploring the Focus-morphology interface: Morpho-syntactic aspects of non- prosodic Focus? María Carmen Parafita Couto and Michael Putnam Kenyon College/Bangor University and Carson-Newman College 1. Introduction This paper claims that a constraint... this hypothesis. Point in case, Parafita (2005) demonstrates that Galician permits rightward movement of the Focused subject in inflected infinitival constructions, as illustrated in (7) below. (7) a. Para ir-es ó partido ti, tiñan que ser as entradas ben baratas...

Parafita Couto, Marí a Carmen; Putnam, Michael

2008-01-01

413

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)

2007-10-30

414

Research Focus Stress hormones and mate choice  

E-print Network

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

Husak, Jerry F.

415

2012November IN-FOCUSIN-FOCUS  

E-print Network

Building Council. "Schools that have a good Green Rating will put graduates a step ahead of the competition2012November IN-FOCUSIN-FOCUS Letters&Science "But hands-on experience and skill- building are very and the interdisciplinary CES framework also encourage individualism and entrepreneurism. There's a thriving "green jobs

Saldin, Dilano

416

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

417

SPECIAL FOCUS CURRENT SCIENCE, 2013 1  

E-print Network

and Bhutan and Nepal facing future melting glaciers. In Bangladesh, for example, until about 2000, hardly anySPECIAL FOCUS CURRENT SCIENCE, 2013 1 Science journalism in South Asia ­ untapped potential T. V. Padma When I was to take over as the South Asia news editor and regional coordina- tor at Sci

Joshi, Yogesh Moreshwar

418

Focusing magnets for HIF based on racetracks  

Microsoft Academic Search

Heavy ion fusion (HIF) is considered a promising path to a practical fusion reactor. A driver for a HIF reactor will require a large number of quadrupole arrays to focus heavy ion beams. A conceptual design, and trade off studies of the quadrupole array based on racetracks are presented. A comparison with a conventional shell magnet is given and advantages

Nicolai N. Martovetsky; Robert R. Manahan

2001-01-01

419

The plasma focus as a thruster  

E-print Network

for the degree of MASTER OF SCIENCE Approved as to style and content by: _____________________ Bruce Freeman (Chair of Committee) _____________________ Wayne Saslow (Member) _____________________ James Rock (Member...) _____________________ William Burchill (Head of Department) December 2004 Major Subject: Nuclear Engineering iii ABSTRACT The Plasma Focus as a Thruster. (December 2004) Richard Lee Hardy, B.S., Texas A&M University Chair of Advisory Committee: Dr. Bruce L...

Hardy, Richard Lee

2005-02-17

420

National Ignition Facility design focuses on optics  

Microsoft Academic Search

Sometime in the year 2002, scientists at the National Ignition Facility (NIF) will focus 192 separate high-power ultraviolet laser beams onto a tiny capsule of deuterium and tritium, heating and compressing the material until it ignites and burns with a burst of fusion energy. The mission of NIF, which will contain the largest laser in the world, is to obtain

W. J. Hogan; L. J. Atherton; J. A. Paisner

1996-01-01

421

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

422

Presentational Focus in Heritage and Monolingual Spanish  

ERIC Educational Resources Information Center

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

Hoot, Bradley

2012-01-01

423

Sonoluminescence and other energy focusing phenomena  

Microsoft Academic Search

Fluids and solids that are driven off equilibrium do not return smoothly to the equilibrium state. Instead they can display a wide range of energy focusing phenomena. In sonoluminescence a sound wave passing through a fluid has its energy concentrated by 12 orders of magnitude to create ultraviolet picosecond flashes of light. For 30KHz sound waves the spectrum is a

Seth Putterman

2005-01-01

424

Focus of NASA's Spaceliner 100 Investment Area  

NASA Technical Reports Server (NTRS)

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

Hueter, Uwe; Lyles, Garry (Technical Monitor)

2000-01-01

425

Focus Article Linking genome to epigenome  

E-print Network

-resolution maps of the entire epigenome which can be compared to gain functional insights. Significant differencesFocus Article Linking genome to epigenome Guo-Cheng Yuan1,2 Recent epigenomic studies have of epigenetic patterns among different cell types. The epigenome is maintained by the complex network of a large

Yuan, Guo-Cheng "GC"

426

Focusing and shadowing of ELF signals  

Microsoft Academic Search

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

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

1986-01-01

427

Family Life Education: Focus on Student Involvement.  

ERIC Educational Resources Information Center

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

Green, Kinsey B.

428

Teaching Introductory Physics with an Environmental Focus  

ERIC Educational Resources Information Center

Throughout North America the curriculum of introductory physics courses is nearly standardized. In 1992, Tobias wrote that four texts dominate 90% of the introductory physics market and current physics education research is focusing on how to sustain educational reforms. The instructional team at the University of British Columbia (UBC) recently…

Martinuk, Mathew; Moll, Rachel F.; Kotlicki, Andrzej

2010-01-01

429

Report From Project Focus: Strategies for Change.  

ERIC Educational Resources Information Center

This report is a product of Project Focus which was initiated as a study effort by the American Association of Junior Colleges to determine the long-range goals of the nation's community and junior colleges. Data gathered from questionnaires administered to a cross-sectional sample of students, faculty, presidents, and institutions are presented…

Bushnell, David S.; Zagaris, Ivars

430

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

431

Regional Focus on GM Crop Regulation  

E-print Network

for com- mercial genetically modified (GM) crops in both the scientific and regulatory arena. The release for genetically modified crops," Economist, 20 Nov. 2004, p. 65. 2. J. Huang et al., Science 308, 688 (2005). 3. CRegional Focus on GM Crop Regulation THE RECENT MEDIA COVERAGE OF THE DEVEL- opments in Brazil

Church, George M.

432

Reading Motivation: A Focus on English Learners  

ERIC Educational Resources Information Center

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

Protacio, Maria Selena

2012-01-01

433

Superintendent Leadership: Focusing on District Culture  

ERIC Educational Resources Information Center

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

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

2012-01-01

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

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

436

100 Area burial grounds focused feasibility study  

SciTech Connect

This document provides the results of a focused feasibility study that was conducted to evaluate alternatives for the remediation of 45 burial grounds located in the 100 Areas of the Hanford Site. The burial grounds were used for near-surface disposal of solid wastes containing radioactive and hazardous substances generated during operation of the Hanford Site's nine former plutonium production reactors.

Dronen, V.R.

2000-03-06

437

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

438

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.

439

Self-focusing hidden bar code  

Microsoft Academic Search

A new type of diffractive optical bar code produced by computer-generated holographic technology is proposed. The message in the proposed bar code is hidden in the diffracted light of the bar code element and can be read from the first diffraction order. In contrast to the conventional hidden bar code, which needs a lens to focus the diffracted light, the

Zhiqiang Zhong; Jianping Ding; Zhou Jin; Peiying Liang; Gao Wenqi

2002-01-01

440

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

441

Subsidies in automotive industry CEOP in focus  

Microsoft Academic Search

In my essay I am going to examine the experiences of the National Development Plan I. This scheme is a document that concerns the development strategy of Hungary for the first three years' planning after joining the European Union (2004-2006). I concentrate on the short period e ects on economy, and I focus on the specific purposes of a more

Nóra Kemenczei

2007-01-01

442

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

443

Controlled Spatiotemporal Focusing Through Turbid Media  

E-print Network

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

Katz, Ori; Small, Eran; Silberberg, Yaron

2010-01-01

444

International Focus: Highlighting APPA Members Worldwide  

ERIC Educational Resources Information Center

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

Glazner, Steve, Comp.

2011-01-01

445

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

446

Gifted and Talented Students. IDRA Focus.  

ERIC Educational Resources Information Center

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

IDRA Newsletter, 1998

1998-01-01

447

Analytical modeling of line focus solar collectors  

NASA Astrophysics Data System (ADS)

Simplified models relating deviations in outlet temperature to changes in inlet temperature, insolation, and fluid flow rate are illustrated. The basic responses and the distributed parameter nature of line focus collectors are described. Detailed models were used to develop transfer functions and frequency response curves useful for design.

Wright, J. D.

1980-04-01

448

Quality? Is it Allowed? FACTC Focus, 2006  

ERIC Educational Resources Information Center

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

Doerr, Mark, Ed.

2006-01-01

449

REPRODUCTIONEDITORIAL Focus on determinants of male fertility  

E-print Network

in vitro (e.g. by in vitro fertilization) or in vivo (e.g. by artificial insemination). The latterREPRODUCTIONEDITORIAL Focus on determinants of male fertility E R S Roldan Reproductive Ecology the main determinants of male fertility would allow us to advance our knowledge of male reproductive

Museo Nacional de Ciencias Naturales

450

Reframing Retention Strategy: A Focus on Process  

ERIC Educational Resources Information Center

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

Schroeder, Charles C.

2013-01-01

451

FOCUS: MARINE GEOMORPHOLOGY AS A DETERMINANT FOR  

E-print Network

FOCUS: MARINE GEOMORPHOLOGY AS A DETERMINANT FOR ESSENTIAL LIFE HABITAT AND MARINE PROTECTED AREA DESIGN Marine Geomorphology in the Design of Marine Reserve Networks William D. Heyman Texas A Geographer explores the development of marine reserve networks based on geomorphology, fish biology

Wright, Dawn Jeannine

452

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

453

Detecting Earthquakes--Part 2.  

ERIC Educational Resources Information Center

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

Isenberg, C.; And Others

1983-01-01

454

Optimal detection and control strategies for invasive species management  

Microsoft Academic Search

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

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

2007-01-01

455

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

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

456

Early Detection  

Cancer.gov

This group identifies and ascertains the effectiveness of both the operating characteristics and the impacts on mortality, and immediate and downstream risks of molecular and imaging cancer