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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

High Intensity Focused Ultrasound induced Gene Activation in Solid Tumors  

NASA Astrophysics Data System (ADS)

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

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

2006-05-01

3

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

Photoacoustic micro-imaging of focused ultrasound induced blood-brain-barrier opening in a rat model  

NASA Astrophysics Data System (ADS)

Blood brain barrier (BBB) prevents most of the drug from transmitting into the brain tissue and decreases the treatment performance for brain disease. One of the methods to overcome the difficulty of drug delivery is to locally increase the permeability of BBB with high-intensity focused ultrasound. In this study, we have investigated the feasibility of photoacoustic microscopy of focused-ultrasound induced BBB opening in a rat model in vivo with gold nanorods (AuNRs) as a contrast agent. This study takes advantage of the strong near-infrared absorption of AuNRs and their extravasation tendency from BBB opening foci due to their nano-scale size. Before the experiments, craniotomy was performed on rats to provide a path for focused ultrasound beam. Localized BBB opening at the depth of about 3 mm from left cortex of rat brains was achieved by delivering 1.5 MHz focused ultrasound energy into brain tissue in the presence of microbubbles. PEGylated AuNRs with a peak optical absorption at ~800 nm were then intravenously administered. Pre-scan prior to BBB disruption and AuNR injection was taken to mark the signal background. After injection, the distribution of AuNRs in rat brains was monitored up to 2 hours. Experimental results show that imaging AuNRs reveals BBB disruption area in left brains while there are no changes observed in the right brains. From our results, photoacoustic imaging plus AuNRs shows the promise as a novel monitoring strategy in identifying the location and variation of focused-ultrasound BBB-opening in a rat model.

Wang, Po-Hsun; Hsu, Po-Hung; Liu, Hao-Li; Wang, Churng-Ren Chris; Li, Meng-Lin

2010-02-01

5

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

NASA Astrophysics Data System (ADS)

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

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

2005-11-01

6

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

PubMed

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/cm 2 . 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. PMID:25354118

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

2014-10-01

7

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

8

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

9

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

10

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

PubMed

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

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

2014-02-21

11

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

12

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

NASA Astrophysics Data System (ADS)

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

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

2010-03-01

13

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

PubMed Central

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

14

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

15

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

PubMed Central

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

Samiotaki, Gesthimani; Konofagou, Elisa E.

2014-01-01

16

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

PubMed

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

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

2005-10-21

17

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

18

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

19

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

20

Efficient Focusing and Face Detection  

Microsoft Academic Search

We present an algorithm for shape detection and apply it to frontal views of faces in stillgrey level images with arbitrary backgrounds. Detection is done in two stages: (i) "focusing,"during which a relatively small number of regions-of-interest are identified, minimizing computationand false negatives at the (temporary) expense of false positives; and (ii) "intensiveclassification," during which a selected region-of-interest is labeled

Bruno Jedynak; Donald Geman

1998-01-01

21

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

22

Ultrasound-Induced Disruption of Amphiphilic Block Copolymer Micelles  

E-print Network

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

Zhao, Yue

23

Improved astigmatic focus error detection method  

NASA Technical Reports Server (NTRS)

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

Bernacki, Bruce E.

1992-01-01

24

Landing airplanes, detecting traffic, and dark focus.  

PubMed

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

Roscoe, S N

1982-10-01

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 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

26

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

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

Ultrasound-induced release of micropallets with cells  

PubMed Central

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

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

2012-01-01

29

d Original Contribution EFFECTIVE PARAMETERS FOR ULTRASOUND-INDUCED IN VIVO  

E-print Network

d Original Contribution EFFECTIVE PARAMETERS FOR ULTRASOUND-INDUCED IN VIVO NEUROSTIMULATION RANDY of Bioengineering, Stanford University, Stanford, CA, USA; y Howard Hughes Medical Institute, Stanford, CA, USA; z) Abstract--Ultrasound-induced neurostimulation has recently gained increasing attention, but little is known

Newsome, William

30

Detection of Inclusion in Molten Metal by Focused Ultrasonic Wave  

Microsoft Academic Search

An attempt for detecting impurity particles suspended in molten zinc at 650°C has been made using a focused ultrasonic pulse-echo technique with a clad metallic buffer rod. The focused ultrasonic waves are generated by a spherical acoustic lens which is fabricated at the end of the buffer rod. An experiment is carried out at 10 MHz. The result shows that

Ikuo Ihara; Cheng-Kuei Jen; Demartonne Ramos França

2000-01-01

31

Preface to the Focus Issue: Chaos Detection Methods and Predictability  

NASA Astrophysics Data System (ADS)

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

Gottwald, Georg A.; Skokos, Charalampos

2014-06-01

32

Improving web servers focused DoS attacks detection  

Microsoft Academic Search

On the Internet, web servers are often the main interface between companies or individuals and the rest of the world. As a result they represent valuable targets for attackers. Although several types of attacks are possible against web server we focus in this paper on flooding based denial of service attacks. We explore the detection of saturation attacks against web

Olivier Paul

33

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

34

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

PubMed

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

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

2014-12-01

35

Localization of ultrasound-induced in vivo neurostimulation in the mouse model.  

PubMed

Developments in the use of ultrasound to stimulate and modulate neural activity have raised the possibility of using ultrasound as a new investigative and therapeutic tool in brain research. Although the phenomenon of ultrasound-induced neurostimulation has a long history dating back many decades, until now there has been little evidence of a clearly localized effect in the brain, a necessary requirement for the technique to become genuinely useful. Here we report clearly distinguishable effects in sonicating rostral and caudal regions of the mouse motor cortex. Motor responses measured by normalized electromyography in the neck and tail regions changed significantly when sonicating the two different areas of motor cortex. Response latencies varied significantly according to sonication location, suggesting that different neural circuits are activated depending on the precise focus of the ultrasound beam. Taken together, our findings present good evidence of the ability to target selective parts of the motor cortex with ultrasound neurostimulation in the mouse, an advance that should help to set the stage for developing new applications in larger animal models, including humans. PMID:24642220

King, Randy L; Brown, Julian R; Pauly, Kim Butts

2014-07-01

36

Computer-assisted detection of epileptiform focuses on SPECT images  

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

37

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

38

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

39

Underground focusing spotlight synthetic aperture radar for tunnel detection applications  

Microsoft Academic Search

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

Jose A. Martinez-Lorenzo; Carey Rappaport

2009-01-01

40

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."

41

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

42

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

43

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

44

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

Microsoft Academic Search

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

Carey M. Rappaport; Jose Angel Martinez Lorenzo

2009-01-01

45

Modeling and simulation of a detecting method for segmented mirror co-focus  

NASA Astrophysics Data System (ADS)

Segmented mirror method is widely adopted in large optical telescopes nowadays in the world. Using segmented mirrors to make up a large mirror requires the segmented mirrors co-focus. It needs corresponding co-focus detecting methods to measure the co-focus errors. In China this kind of research is insufficient nowadays. In the paper, Zernike polynomial is used as Optical-Mechanical Interface, with the help of the engineering softwares, such as UG, Patran, Matlab, and the optical software CODE V to model and simulate the widely used Shack-Hartmann method. The relationship between S-H measurement and segmented mirror co-focus is found. Finally, a computer aided design method for optical measuring of segmented mirror co-focus is proposed.

Luo, Yong; Wang, Jing; Sun, Shengli; Chen, Guilin

2006-02-01

46

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

Microsoft Academic Search

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

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

2010-01-01

47

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

48

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

NASA Astrophysics Data System (ADS)

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

Domené, E. A.; Martínez, O. E.

2013-01-01

49

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

50

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

51

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

52

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

53

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

54

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

55

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

56

Magnetic focusing immunosensor for the detection of Salmonella typhimurium in foods  

NASA Astrophysics Data System (ADS)

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

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

1999-01-01

57

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

NASA Astrophysics Data System (ADS)

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

Baac, Hyoung Won

58

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

59

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

60

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

PubMed

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

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

2014-11-28

61

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

62

Ultrasoft (C,N,O) x-ray fluorescence detection: Proportional counters, focusing multilayer mirrors, and scattered light systematics  

SciTech Connect

Ultrasoft x-ray detection is discussed as applied to the fluorescence yield near edge spectroscopy (FYNES) technique. We describe a progression of improved ultra-high vacuum compatible soft x-ray proportional counters for FYNES measurements. The importance of energy dispersive detection is discussed and examples shown. Scattered light background problems are quantified and compared for several real samples. Finally, focusing multilayer mirror collection is introduced for reducing scattered light background and improved elemental differentiation in the fluorescence signal.

Fischer, D. A.; Colbert, J.; Gland, J. L.

1989-07-01

63

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

64

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

65

Ultrasound-induced blood-brain barrier opening for drug delivery.  

PubMed

Treatment of central nervous system (CNS) diseases is highly limited due to the presence of the blood-brain barrier (BBB), which prevents the entry of approximately 99% of potential therapeutic agents into the CNS. Focused ultrasound (FUS) in combination with microbubbles can lead to a transient and focal opening of the BBB, thus enabling the passage of therapeutic agents across the BBB. Mechanical ultrasound effects, such as stable and inertial cavitation, contribute to BBB opening, possibly via transient disintegration of tight junctions. Facilitation of transcellular passage through vesicle transport may also be influenced. FUS-induced BBB opening can be performed without tissue damage, given an optimal set of ultrasound parameters. However, the risk of parenchymal damage or microhaemorrhage increases with increasing acoustic energy. To date, several therapeutic substances, such as chemotherapeutics, antibodies, plasmids and viral vectors, have successfully been delivered to the CNS by FUS-induced BBB opening in animal models, including non-human primates. Translation to a clinical application is pending. © 2015 S. Karger AG, Basel. PMID:25531667

Alonso, Angelika

2015-01-01

66

Optimization of the Ultrasound-Induced Blood-Brain Barrier Opening  

PubMed Central

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

Konofagou, Elisa E.

2012-01-01

67

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

68

Detection of measles, mumps and rubella viruses by immuno-colorimetric assay and its application in focus reduction neutralization tests.  

PubMed

Measles, mumps and rubella are vaccine-preventable diseases; however limited epidemiological data are available from low-income or developing countries. Thus, it is important to investigate the transmission of these viruses in different geographical regions. In this context, a cell culture-based rapid and reliable immuno-colorimetric assay (ICA) was established and its utility studied. Twenty-three measles, six mumps and six rubella virus isolates and three vaccine strains were studied. Detection by ICA was compared with plaque and RT-PCR assays. In addition, ICA was used to detect viruses in throat swabs (n?=?24) collected from patients with suspected measles or mumps. Similarly, ICA was used in a focus reduction neutralization test (FRNT) and the results compared with those obtained by a commercial IgG enzyme immuno assay. Measles and mumps virus were detected 2 days post-infection in Vero or Vero-human signaling lymphocytic activation molecule cells, whereas rubella virus was detected 3 days post-infection in Vero cells. The blue stained viral foci were visible by the naked eye or through a magnifying glass. In conclusion, ICA was successfully used on 35 virus isolates, three vaccine strains and clinical specimens collected from suspected cases of measles and mumps. Furthermore, an application of ICA in a neutralization test (i.e., FRNT) was documented; this may be useful for sero-epidemiological, cross-neutralization and pre/post-vaccine studies. PMID:25244651

Vaidya, Sunil R; Kumbhar, Neelakshi S; Bhide, Vandana S

2014-12-01

69

Mass spectrometry detection and imaging of inorganic and organic explosive device signatures using desorption electro-flow focusing ionization.  

PubMed

We demonstrate the coupling of desorption electro-flow focusing ionization (DEFFI) with in-source collision induced dissociation (CID) for the mass spectrometric (MS) detection and imaging of explosive device components, including both inorganic and organic explosives and energetic materials. We utilize in-source CID to enhance ion collisions with atmospheric gas, thereby reducing adducts and minimizing organic contaminants. Optimization of the MS signal response as a function of in-source CID potential demonstrated contrasting trends for the detection of inorganic and organic explosive device components. DEFFI-MS and in-source CID enabled isotopic and molecular speciation of inorganic components, providing further physicochemical information. The developed system facilitated the direct detection and chemical mapping of trace analytes collected with Nomex swabs and spatially resolved distributions within artificial fingerprints from forensic lift tape. The results presented here provide the forensic and security sectors a powerful tool for the detection, chemical imaging, and inorganic speciation of explosives device signatures. PMID:24968206

Forbes, Thomas P; Sisco, Edward

2014-08-01

70

Fibre-optic focus-detection system for non-contact, high-resolution thickness measurement of transparent tissues  

NASA Astrophysics Data System (ADS)

A low-cost, high-resolution, fibre optic system for non-contact thickness measurement of ocular tissues in cadaver eyes was developed. The optical system uses direct modulation at 100 kHz of a 670 nm laser diode delivered to a single-mode fibre coupler. The output of the fibre coupler is focused onto the tissue using a high numerical aperture aspheric lens mounted on a motorized translation stage. Light reflected from the sample is collected by the fibre coupler and sent to a photoreceiver. Peaks in the power signal are detected when the focal point of the aspheric lens coincides with the tissue boundaries. The thickness is proportional to the distance between successive peaks. The optical system has a sensitivity of 52 dB, which corresponds to a detectable change in the refractive index of 0.005 at a boundary-assuming specular reflection. With a focusing numerical aperture of 0.68, the resolution is 4.0 µm and the precision is ± 0.2 µm. The optical system was used to measure the corneal layers and lens capsule thickness of cadaver monkeys eyes. The system was able to measure the thickness of the epithelium, stroma and Descemet's membrane of the cornea, as well as the lens capsule and lens epithelial cell layer.

Ziebarth, Noël; Manns, Fabrice; Parel, Jean-Marie

2005-08-01

71

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

72

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

73

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

74

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

75

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

PubMed

F 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 (\\(\\uplambda_{\\textsc{ex}}\\sim\\) nm, \\(\\uplambda_{\\textsc{em}}\\sim\\) 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 proteinlocal environment, which, in addition to fluorescence quenching, has been applied to study protein conformational changes. Intrinsic F 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

76

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

77

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

78

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

PubMed Central

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

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

2011-01-01

79

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

PubMed Central

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

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

2013-01-01

80

Detection of unlabeled particles in the low micrometer size range using light scattering and hydrodynamic 3D focusing in a microfluidic system.  

PubMed

In this paper, we describe a microfluidic device composed of integrated microoptical elements and a two-layer microchannel structure for highly sensitive light scattering detection of micro/submicrometer-sized particles. In the two-layer microfluidic system, a sample flow stream is first constrained in the out-of-plane direction into a narrow sheet, and then focused in-plane into a small core region, obtaining on-chip three-dimensional (3D) hydrodynamic focusing. All the microoptical elements, including waveguides, microlens, and fiber-to-waveguide couplers, and the in-plane focusing channels are fabricated in one SU-8 layer by standard photolithography. The channels for out-of-plane focusing are made in a polydimethylsiloxane (PDMS) layer by a single cast using a SU-8 master. Numerical and experimental results indicate that the device can realize 3D hydrodynamic focusing reliably over a wide range of Reynolds numbers (0.5 < Re < 20). Polystyrene particles of three sizes (2, 1, and 0.5 ?m) were measured in the microfluidic device with integrated optics, demonstrating the feasibility of this approach to detect particles in the low micrometer size range by light scattering detection. PMID:22740459

Zhuang, Guisheng; Jensen, Thomas G; Kutter, Jörg P

2012-07-01

81

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

2015-01-20

82

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

83

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

E-print Network

examined by off-axis electron holography David Cooper,1,a Pierrette Rivallin,1 Jean-Michel Hartmann,1 Amal p-n junctions have been prepared for examination by off-axis electron holography using focused ion, techniques that are under develop- ment for dopant profiling include off-axis electron holography,2 scanning

Dunin-Borkowski, Rafal E.

84

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

PubMed

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

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

2014-09-01

85

J. Wu and N. Islam, Integration of In-situ Nano-Particle Focusing with Cantilever Detection 1 Abstract--Real-time detection of low-concentration  

E-print Network

sensitivity is achieved through time-consuming culturing or sophisticated processing, often unfeasible under and bacteria, is important in real-time detection. The paper reports integration on microcantilevers

Wu, Jayne

86

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

87

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

88

Detection  

E-print Network

In this work, we focus on the mainly detection of buildings.. As input data, we use LIDAR data and multispectral aerial images of two different test sites. One is from Zurich airport and the other one is from Vaihingen region close to Stuttgart. Quality assessment has been performed by comparing our results with existing reference data which are generated using commercial photogrammetric software and manual stereo measurement. 1.

unknown authors

89

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

PubMed

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

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

2014-06-01

90

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

91

A focal cortical dysplasia case whose seizure focuses were detected using interhemispheric grid electrode: a technical case report.  

PubMed

We report an 18-year-old boy who presented with seizures at the age of 12 years. He had 3 different kinds of seizures, occurring 4 to 5 times a week, despite adequate antiepileptic treatment. Magnetic resonance imaging (MRI) showed deep paramedian focal cortical dysplasia in the left parietal lobe. Ictal video-EEG demonstrated 5 seizures originating from the left parietal lobe, left hemisphere and right hemisphere. He was submitted to invasive recordings with two frontal strips and an interhemispherical grid that was advanced to the corpus callosum. The lesion and other seizure focuses were resected subpially down to the corpus callosum approximately 1 cm posterior to the motor area. His seizures resumed after three years of quiescence. Postoperative MRI investigation revealed remnants of dysplastic tissue deep in the interhemispheric region, which were silent during the invasive EEG monitorization. We want to re-emphasize that each patient with cortical dysplasia who is a candidate for epilepsy surgery should undergo detailed neuroradiological investigations as well as EEG monitorization, whereas complete resection of the lesion on the basis of findings that are obtained from neuroradiological examination might have a superior effect on the postoperative seizure outcome compared to the findings obtained from EEG recordings. PMID:19263356

Erdem, Atilla; Açik, Vedat; Levento?lu, Alev; Sarilar, Caner; Cansu, Ali

2009-01-01

92

Homogeneous immunoglobulins in the sera of lung carcinoma patients receiving cytotoxic chemotherapy--detection with the use of isoelectric focusing and immunoblotting.  

PubMed Central

Using isoelectric focusing (IEF) with immunoblotting, we have analysed serum immunoglobulins of 15 lung cancer patients on cytotoxic chemotherapy. In five of the patients homogeneous immunoglobulins were found which appeared between 9 and 18 months after beginning of treatment and were monoclonal in two and oligoclonal in three cases. These abnormalities were only partially shown by zonal electrophoresis with immunofixation and not detected by immune electrophoresis. Examination of 10 normal and 10 myeloma sera by the three techniques in parallel confirmed the competence and sensitivity of IEF with immunoblotting in detecting homogeneous immunoglobulins. Thus, this method provides a valuable tool for investigating an abnormal regulation of the immunoglobulin synthesis. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:3325203

Haas, H; Lange, A; Schlaak, M

1987-01-01

93

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

94

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

95

Tsunami focusing  

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

96

Semantic Focus and Sentence Comprehension.  

ERIC Educational Resources Information Center

Reaction time to detect a phoneme target in a sentence was faster when the target-containing word formed part of the semantic focus of the sentence. Sentence understanding was facilitated by rapid identification of focused information. Active search for accented words can be interpreted as a search for semantic focus. (Author/RD)

Cutler, Anne; Fodor, Jerry A.

1979-01-01

97

On-line focusing of 5-hydroxy-tryptamine type 3 receptor antagonists via the combination of field-enhanced sample injection and dynamic pH junction in capillary electrophoresis with amperometric detection.  

PubMed

In the present work, an on-line dual focusing technique based on field-enhance sample injection (FASI) and dynamic pH junction (DypH) was developed for the analysis of two 5-hydroxy-tryptamine type 3 receptor (5-HT3) antagonists ondansetron (Ond) and tropisetron (Tro) by capillary electrophoresis with amperometric detection (CE-AD) system. By preparing the sample in a lower conductivity (FASI condition) and lower pH value (DypH condition) matrix relative to the background electrolyte (BGE) solution, a simple and effective dual focusing approach, FASI-DypH was achieved. In this stacking mode, a large amount of analytes could be electrokinetically injected into the capillary and stacked at the boundary of the sample and the BGE zone as a result of deprotonation and decrease in the electric field. Effects of separation, detection and FASI-DypH focusing conditions were investigated in detail. Under the optimum conditions, good separation for Ond and Tro was achieved within 8min. In comparison with the conventional CE-AD analysis method, the present dual focusing technique enabled the enhancement factors in terms of peak heights to reach 357-fold and 345-fold for Ond and Tro, respectively. The limits of detection (LODs) (S/N=3) for Ond and Tro were 2nM and 5nM, respectively. The intraday and interday repeatabilities (RSDs) were less than 4.5% and 2.9% for peak height and migration time, respectively. The proposed method was successfully applied for the analysis of Ond and Tro in human urine sample. PMID:24461640

Li, Libo; Xu, Lei; Huang, Jianshe; You, Tianyan

2014-02-28

98

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

99

A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse  

NASA Astrophysics Data System (ADS)

Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity (?E/E~1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 108-109 2.45 MeV and 1010-1011 14 MeV neutrons per pulse with pulse duration ~10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation—1 litre bottles with methanol (CH3OH), phosphoric (H2PO4) and nitric (HNO3) acids as well as a long object—a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

Gribkov, V. A.; Latyshev, S. V.; Miklaszewski, R. A.; Chernyshova, M.; Drozdowicz, K.; Wi?cek, U.; Tomaszewski, K.; Lemeshko, B. D.

2010-03-01

100

Adaptive focusing - The likelihood ratio  

NASA Astrophysics Data System (ADS)

The problem of detecting a certain non-Gaussian random acoustic signal field in a spatially white Gaussian noise field is solved within the formalism of classical detection theory. Two solutions of the problem are compared: the maximum-likelihood or adaptive-focusing receiver and the Neyman-Pearson or adaptive focusing optimal (AFO) receiver. Based on two criteria for comparison, it is found that the two receivers differ only slightly in performance, with the AFO, of course, being the better. One of the criteria is based on the signal deflection ratio, and the other is the receiver operating characteristic curve. The comparisons are done for a Monte Carlo simulation.

Labianca, F. M.; Lloyd, S. P.

1981-08-01

101

"Only" and Focus.  

ERIC Educational Resources Information Center

The relationship of the word "only," one of a class of words known as scalar particles, focus adverbs, focus inducers, or focus-sensitive particles, with the "focus" of the sentence is examined. It is suggested, based on analysis of discourse structure, that this "association with focus" is not an inherent property of this scalar particle. The…

Vallduvi, Enric

102

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

103

Focus Sensitive Coordination  

E-print Network

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

Hulsey, Sarah McNearney

2008-01-01

104

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

105

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."

106

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

107

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.

108

Agreement, Shells, and Focus.  

ERIC Educational Resources Information Center

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

Simpson, Andrew; Wu, Zoe

2002-01-01

109

Focus, 2000-2001.  

ERIC Educational Resources Information Center

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

Focus, 2001

2001-01-01

110

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

Microsoft Academic Search

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

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

2011-01-01

111

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

112

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.

113

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

114

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

115

STRATEGIC FOCUS: Sustainable Systems  

E-print Network

in solar power generation, controls, and management as well as in alternate and new energy re- sources1010 STRATEGIC FOCUS: Sustainable Systems Biology doctoral student Tanya Lubansky uses quan and quantitative ecologists. Sustainable Systems in NJIT's Educational Programs Educational offerings

116

Facility Focus: Food Service.  

ERIC Educational Resources Information Center

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

College Planning & Management, 2002

2002-01-01

117

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

118

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

119

Portable thermal lens spectrometer with focusing system.  

PubMed

A portable thermal lens spectrometer with a precise focusing system was developed. Astigmatism of the reflected excitation beam from the microchip was used for depth direction focusing. For width direction focusing, the scattering effect of the transmitted probe beam by a microchannel edge was used. The focusing system was evaluated with a 250 microm wide x 50 microm deep microchannel. Focusing resolutions for depth and width directions were 1 and 10 microm, respectively. The repeatability of the thermal lens signal (40 microM xylenecyanol solution) was proved to be approximately 1% coefficient of variance when using these focusing methods. The limit of detection for a xylenecyanol solution was 30 nM, and the absorbance was 4.7 x 10(-6) AU. The sensitivity was 20-100 times higher than that obtained by spectrophotometry. In consequence, a practical thermal lens spectrometer was realized. PMID:15649072

Mawatari, Kazuma; Naganuma, Yoshiaki; Shimoide, Koji

2005-01-15

120

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

121

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

PubMed Central

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

2013-01-01

122

NICMOS focus monitor  

NASA Astrophysics Data System (ADS)

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

Schneider, Glenn

1997-07-01

123

Temporal focusing microscopy.  

PubMed

Axial localization of multiphoton excitation to a single plane is achieved by temporal focusing of an ultrafast pulsed excitation. We take advantage of geometrical dispersion in an extremely simple experimental setup, where an ultrashort pulse is temporally stretched and hence its peak intensity is lowered outside the focal plane of the microscope. Using this strategy, out-of-focus multiphoton excitation is dramatically reduced, and the achieved axial resolution is comparable to line-scanning multiphoton microscopy for wide-field excitation and to point-scanning multiphoton microscopy for line excitation. In this introduction, we provide a detailed description of the considerations in choosing the experimental parameters, as well as the alignment of a temporal focusing add-on to a multiphoton microscope. We also review current advances and applications for this technique. PMID:25646508

Oron, Dan; Silberberg, Yaron

2015-01-01

124

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

125

Sagittal focusing Laue monochromator  

DOEpatents

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

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

2009-03-24

126

Divergent flow isoelectric focusing.  

PubMed

Continuous-flow isoelectric focusing (IEF) has the potential to be an important method in proteome analysis. The current devices do not fully use the advantages of IEF, because they do not utilize all its important features including changes in background conductivity during the focusing. A novel continuous-flow IEF method has been developed based on planar divergent flow and control of local electric field by conductivity of electrode electrolytes. A hydrophilized polypropylene nonwoven fabric was used for creation of flow and electric manifold, making the assembled device cheap, flexible and easy to set up and operate. By using the colored low-molecular-weight pI markers we demonstrated much higher speed of focusing in the new designed channel in comparison with a channel based on currently used rectangular geometry. The developed divergent-flow IEF combines the speed of micro flow channels with the separation efficiency and sample load capacity of preparative devices. PMID:18494026

Slais, Karel

2008-06-01

127

Focus: International Economics.  

ERIC Educational Resources Information Center

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

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

128

Homework. Focus On  

ERIC Educational Resources Information Center

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

Rahal, Michelle Layer

2010-01-01

129

Focus on Speaking.  

ERIC Educational Resources Information Center

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

Burns, Anne; Joyce, Helen

130

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

131

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

132

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

133

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

134

Focus on the President.  

ERIC Educational Resources Information Center

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

Optometric Education, 1996

1996-01-01

135

Conservation Focus and Executive  

E-print Network

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

136

[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

137

Education Policy. IDRA Focus.  

ERIC Educational Resources Information Center

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

IDRA Newsletter, 1998

1998-01-01

138

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

139

Quality-Focused Management.  

ERIC Educational Resources Information Center

Presents the quality-focused management (QFM) system and explains the departure QFM makes from established community college management practices. Describes the system's self-directed teams engaged in a continuous improvement process driven by customer demand and long-term commitment to quality and cost control. (13 references.) (MAB)

Needham, Robbie Lee

1993-01-01

140

.: Optics & Photonics Focus  

E-print Network

in Time Day-to-day life common sense often does not apply in science. But sometimes it works better than's commercial cameras is limited by the use of solid lenses and rigid detector chips. Biologically a system that can focus just like the eye -- using only a small, flexible lens and a curved detector

Rogers, John A.

141

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

142

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

143

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

144

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

145

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

146

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

147

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

148

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

149

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

150

Focus Issue: Drug Discovery  

NSDL National Science Digital Library

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

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

2005-08-02

151

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

152

SecurityFocus  

NSDL National Science Digital Library

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

1999-01-01

153

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

154

Regadenoson: a focused update.  

PubMed

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

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

2013-04-01

155

In Focus: The Tree  

NSDL National Science Digital Library

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

156

Focusing on customer service.  

PubMed

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

1996-01-01

157

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

158

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.

159

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.

160

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

161

Embedded Hardware Face Detection  

Microsoft Academic Search

Face detection is the first step towards face recognition and is a vital task in surveillance and security applications. Current software implementations of face detection algorithms lack the computational ability to support detection in real time video streams. Consequently, this work focuses on the design of special-purpose hardware for performing rotation invariant face detection. The synthesized design using 160nm technology

Theo Theocharides; Greg M. Link; Narayanan Vijaykrishnan; Mary Jane Irwin; Wayne Wolf

2004-01-01

162

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

163

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

164

Focusators for laser-branding  

NASA Astrophysics Data System (ADS)

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

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

165

Remote lensless focusing of a light beam  

E-print Network

Remote focusing of light in a graded-index medium via mode interference is demonstrated using exact analytical solutions of the wave equation. Strong focusing of light occurs at extremely long distances and it revivals periodically with distance due to mode interference. High efficiency transfer of a strongly focused subwavelength spot through optical waveguide over large distances takes place with a period of revival. Super-oscillatory hot-spots with the sizes which are beyond the conventional Abbe diffraction limit can be observed at large distances from the source. This can provide the possibility to detect optical super-resolution information in the far-field without any evanescent waves. Far-field super-resolution imaging capabilities of a graded-index waveguide are also analyzed.

Petrov, Nikolai I

2015-01-01

166

The theory of ionospheric focused heating  

NASA Technical Reports Server (NTRS)

Ionospheric modification by high power radio waves and by chemical releases are combined in a theoretical study of ionospheric focused heating. The release of materials which promote electron-ion recombination creates a hole in the bottomside ionosphere. The ionospheric hole focuses high power radio waves from a ground-based transmitter to give a 20 dB or greater enhancement in power density. The intense radio beam excites atomic oxygen by collisions with accelerated electrons. Airglow from the excited oxygen provides a visible trace of the focused beam. The large increase in the intensity of the radio beam stimulates new wave-plasma interactions. Numerical simulations show that the threshold for the two-plasmon decay instability is exceeded. The interaction of the pump electromagnetic wave with the backward plasmon produces a scattered electromagnetic wave at 3/2 the pump frequency. The scattered wave provides a unique signature of the two-plasmon decay process for ground-based detection.

Bernhardt, P. A.; Duncan, L. M.

1987-01-01

167

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

168

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

169

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

170

Hyperkähler metric and GMN ansatz on focus-focus fibrations  

NASA Astrophysics Data System (ADS)

In this paper, we study the hyperkähler metric and practise GMN's construction of hyperkähler metric on focus-focus fibrations. We explicitly compute the action-angle coordinates on the local model of focus-focus fibrations, and show its semi-global invariant should be harmonic to admit a compatible holomorphic 2-form. Then we study the canonical semi-flat metric on it. After the instanton correction, finally we are able to get a reconstruction of the generalized Ooguri-Vafa metric.

Zhao, Jie

2015-01-01

171

Longitudinal seam weld characterization by focused ultrasonics  

NASA Astrophysics Data System (ADS)

Increasingly, the detectability limits placed on inspection methodologies applied to the assessment of critical high energy components in fossil fuelled power plants are being forced to lower values. Most notably, recent events involving longitudinal seam welded piping have raised the question of lowering the detectibility limit for ultrasonics to a level necessary for resolving incipient creep damage. Historically, several testing methods were required for the detection of defects over the range of anticipated flaw sizes in an economically and technically acceptable manner. However, unyielding limitations exist for several of these currently used methods. While accepting that the detection of isolated creep cavities is not technically feasible with current conventional ultrasonic methods, the detection of high density cavitation sheets or zones prior to microcrack initiation has been demonstrated and successfully applied to field inspection of critical welds using focused ultrasonics. This paper describes the equipment and verification process used to extend the detectability limit of a field ultrasonic systems for longitudinal seam weld evaluations to approaching that of an acoustic microscope for the identification of incipient creep cavitation.

Bisbee, Laney H.; Nottingham, Lawrence

1996-11-01

172

Mirror alignment and focus of point-focus solar concentrators  

SciTech Connect

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

Diver, R.B.

1994-11-01

173

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

174

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

PubMed

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

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

2014-12-01

175

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

PubMed

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

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

2011-08-15

176

Self-focusing in microemulsions  

NASA Astrophysics Data System (ADS)

We study the self-focusing of the gaussian beam given by the Te00 mode of an Ar+ laser by a thin film of a water in oil microemulsions. As microemulsion we use WAD (AOT/water/decane). First experimental results are presented here for beam self-focusing in a WAD film above and under the percolation line.

Vicari, Luciano R. M.

1999-07-01

177

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

178

Focusing light using negative refraction  

Microsoft Academic Search

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

J. B. Pendry; S. Anantha Ramakrishna

2003-01-01

179

CTE's Focus on Continuous Improvement  

ERIC Educational Resources Information Center

Just one of the ways career and technical education (CTE) is revamping its image is through increased attention to data-driven instructional techniques as a means of improving and focusing instruction on what matters most. Accountability and data have increasingly become a core focus of research, news, and commentary about education in recent…

Foster, John; Kelley, Patricia; Pritz, Sandy; Hodes, Carol

2011-01-01

180

DNA Focusing Using Microfabricated Electrode Arrays  

NASA Astrophysics Data System (ADS)

Focusing methods are a key component in many miniaturized DNA analysis systems because they enable dilute samples to be concentrated to detectable levels while being simultaneously confined within a specified volume inside the microchannel. In this chapter, we describe a focusing method based on a device design incorporating arrays of addressable on-chip microfabricated electrodes that can locally increase the concentration of DNA in solution by electrophoretically sweeping it along the length of a microchannel. By applying a low voltage (1-2 V) between successive pairs of neighboring electrodes, the intrinsically negatively charged DNA fragments are induced to migrate toward and collect at each anode, thereby allowing the quantity of accumulated DNA to be precisely metered. We have characterized the kinetics of this process, and found the response to be robust over a range of different sample compositions and buffer environments.

Shaikh, Faisal A.; Ugaz, Victor M.

181

Camera correlation focus: an image-based focusing technique  

Microsoft Academic Search

Determining the focal position of an overlay target with respect to an objective lens is an important prerequisite of overlay metrology. At best, an out-of-focus image will provide less than optimal information for metrology; focal depth for a high-NA imaging system at the required magnification is of the order of 5 microns. In most cases poor focus will lead to

Greg Reynolds; Mike Hammond; Lewis A. Binns

2005-01-01

182

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

183

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

NASA Astrophysics Data System (ADS)

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

Huang, Jinlan

184

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

185

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

186

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

187

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

188

Oculometer focus and mirror control  

NASA Technical Reports Server (NTRS)

An automatic focusing system designed around an ultrasonic range measurement is described. Besides maintaining the focus, subject distance is a by-product which could lighten the NOVA computational effort. An automatic head tracking unit is also discussed. It is intended to reduce the search time required when track is lost. An X-Y ultrasonic measurement is also made in this design to control the deflection mirrors.

Guy, W. J.

1982-01-01

189

A continuous plasma final focus  

SciTech Connect

Scaling laws are set down for a plasma cell used for transport, focusing and current neutralization of fine, intense, relativistic electron beams. It is found that there exists a minimum beam spot size, {sigma}{sub min} {approximately} {epsilon}{sub n}(I{sub A}/{gamma}I){sup 1/2}, in such a focusing system. Propagation issues, including channel formation, synchrotron radiation, beam ionization and instabilities, are discussed. Three numerical examples are considered. 38 refs., 2 figs., 1 tab.

Whittum, D.H.

1990-02-01

190

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

191

A Generalized Focused Transport Equation  

NASA Astrophysics Data System (ADS)

In recent years interest has developed in using focused transport theory to model the acceleration of energetic charged particles at heliospheric shocks in more detail than possible with the standard Parker transport equation. However, this equation has some limitations when applied to nearly perpendicular shocks related to the assumption of nearly gyrotropic particle phase-angle distributions. Here we present the outline of a derivation of a more general form of the standard focused transport equation and discuss its features.

le Roux, J. A.; Webb, G. M.; Ye, J.

2014-05-01

192

AXAF SIM focus mechanism study  

NASA Astrophysics Data System (ADS)

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

Tananbaum, H. D.; Whitbeck, E.

1994-02-01

193

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

194

Focus, Focus, Focus. Do It Or Die. Entrepreneurs are a creative lot with a  

E-print Network

required to establish a successful company. Brian is Managing Partner at Alpha Sprouts. How to Focus Presented by David Ochi & Brian Dao Managing Partners of Alpha Sprouts When Tuesday, May 20, 2014 11:30 am

Kheradvar, Arash

195

Capillary Isoelectric Focusing of Individual Mitochondria  

PubMed Central

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

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

2011-01-01

196

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

197

Experience with newborn screening using isoelectric focusing.  

PubMed

Electrophoretic techniques are used for hemoglobinopathy diagnosis. Confirmation of the hemoglobin variants is necessary. Currently, citrate agar electrophoresis is the most available, but high performance liquid chromatography is highly recommended in a reference laboratory. Thin layer isoelectric focusing is an excellent technique that can be easily adapted for large-scale newborn hemoglobinopathy screening. Although the initial instrument cost can be about twice as much as the cost for standard electrophoretic equipment, cost-effectiveness for newborn screening is considerable because repeat analysis for uninterpretable results is not necessary. Resolution of hemoglobins is much better with thin layer isoelectric focusing than for any of the other electrophoretic methods currently available, and thin layer isoelectric focusing is the best method to use to establish a definitive diagnosis using newborn blood samples. Cord blood samples may be contaminated with maternal blood, and evaluation of Hb A2 levels in such samples can serve as the method to detect contamination. Follow-up testing is required regardless of the method of blood collection. PMID:2717314

Kleman, K M; Vichinsky, E; Lubin, B H

1989-05-01

198

Magnetically focused liquid drop radiator  

DOEpatents

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

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

1984-12-10

199

Magnetically focused liquid drop radiator  

DOEpatents

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

Botts, Thomas E. (Fairfax, VA); Powell, James R. (Shoreham, NY); Lenard, Roger (Redondo Beach, CA)

1986-01-01

200

Development of an immunofluorescence focus assay for Ebola virus.  

PubMed Central

A 48-h indirect immunofluorescence focus assay for the quantitation of Ebola virus was developed, utilizing HeLa-229 cell monolayers. The dose dependency and the sensitivity of this assay as compared with conventional assays are reported. This indirect immunofluorescence focus assay can be used as a rapid, quantitative test for the detection of Ebola virus, an agent from Africa known to cause hemorrhagic fever. Images PMID:6352735

Truant, A L; Regnery, R L; Kiley, M P

1983-01-01

201

Beam dynamics in the SLC final focus system  

SciTech Connect

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

Bambade, P.S.

1987-06-01

202

Nuclear fusion - Focus on Tokamak  

Microsoft Academic Search

An overview of nuclear fusion engineering is presented covering: basic fusion technology, magnetic and inertial confinement schemes, fusion fuel, tritium breeding, blankets, tritium containment and disposal, fusion process waste management, power generation costs, environmental impact, and safety. Attention is focused on closed magnetic confinement systems, specifically Tokamak systems. The outlook for pulsed\\/batch or continuous Tokamak operation is assessed. Power supplies

D. Steiner

1977-01-01

203

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

204

Focus Article Maintenance and differentiation  

E-print Network

-renewable, multipotent neural stem cells (NSCs) that are responsible for neurogenesis and plasticity in specific regions-renewal and the multipotent state of these cells. This intricate and well-tuned signaling network regulates the tranFocus Article Maintenance and differentiation of neural stem cells Katlin B. Massirer,1 Cassiano

Bellugi, Ursula

205

Student Focused Math Content Coaching  

NSDL National Science Digital Library

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

Foster, David

2012-02-01

206

Focus Issue: Signals to Neurodegeneration  

NSDL National Science Digital Library

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

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

2009-07-21

207

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

208

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

209

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

210

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... guide is located at: http://www.intute.ac.uk/supportdocs/focuson/farming.pdf Date of issue March 2008

Miranda, Eduardo Reck

211

Reader-Focused Text Evaluation.  

ERIC Educational Resources Information Center

Presents a review of the literature on reader-focused text evaluation. Gives an account of the document characteristics that can be evaluated and considers the possible functions of evaluations making a distinction between verifying, troubleshooting, and choice-supporting research. Presents an overview of methods appropriate for the various…

DeJong, Menno; Jan Schellens, Peter

1997-01-01

212

Master of Education focusing on  

E-print Network

.0 Issues in Digital Technology in Education The Graduate Program in Education: Language, CultureMaster of Education focusing on Urban Aboriginal Education A Collaborative Initiative between the Faculty of Education, York University and the TDSB Aboriginal Education Centre In response to the need

213

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.

214

Performance Cements Focus on Sustainability  

E-print Network

. Production and quality control of limestone cements Limestone grinds more easily than clinker OverallPerformance Cements Focus on Sustainability Tim Cost, P.E. Senior Technical Service Engineer tim.cost@holcim.com NCC Meeting Baton Rouge April 9, 2008 #12;2 High Limestone Cements 5/21/08 Cost Holcim (US) Inc

215

Zoonotic Focus of Plague, Algeria  

PubMed Central

After an outbreak of human plague, 95 Xenopsylla cheopis fleas from Algeria were tested for Yersinia pestis with PCR methods. Nine fleas were definitively confirmed to be infected with Y. pestis biovar orientalis. Our results demonstrate the persistence of a zoonotic focus of Y. pestis in Algeria. PMID:17326957

Bitam, Idir; Baziz, Belkacem; Rolain, Jean-Marc; Belkaid, Miloud

2006-01-01

216

Video: Focusing a Compound Microscope  

NSDL National Science Digital Library

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

2013-07-01

217

Standards and Assessment. IDRA Focus.  

ERIC Educational Resources Information Center

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

IDRA Newsletter, 1997

1997-01-01

218

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

219

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

220

Detecting Uncommon Trajectories  

Microsoft Academic Search

An effective video surveillance system relies on detection of suspicious activities. In recent times, there has been an increasing focus on detecting anomalies in human behaviour using surveillance cameras as they provide a clue to preventing breaches in security. Human behaviour can be termed as suspicious when it is uncommon in occurrences and deviates from commonly understood behaviour within a

Arnold Wiliem; Vamsi Krishna Madasu; Wageeh Boles; Prasad K. D. V. Yarlagadda

2008-01-01

221

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

222

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

223

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

224

Dynamically focused fuzzy learning control.  

PubMed

A "learning system" possesses the capability to improve its performance over time by interacting with its environment. A learning control system is designed so that its "learning controller" has the ability to improve the performance of the closed-loop system by generating command inputs to the plant and utilizing feedback information from the plant. Learning controllers are often designed to mimic the manner in which a human in the control loop would learn how to control a system while it operates. Some characteristics of this human learning process may include: (i) a natural tendency for the human to focus their learning by paying particular attention to the current operating conditions of the system since these may be most relevant to determining how to enhance performance; (ii) after learning how to control the plant for some operating condition, if the operating conditions change, then the best way to control the system may have to be re-learned; and (iii) a human with a significant amount of experience at controlling the system in one operating region should not forget this experience if the operating condition changes. To mimic these types of human learning behavior, we introduce three strategies that can be used to dynamically focus a learning controller onto the current operating region of the system. We show how the subsequent "dynamically focused learning" (DFL) can be used to enhance the performance of the "fuzzy model reference learning controller" (FMRLC) and furthermore we perform comparative analysis with a conventional adaptive control technique. A magnetic ball suspension system is used throughout the paper to perform the comparative analyses, and to illustrate the concept of dynamically focused fuzzy learning control. PMID:18263006

Kwong, W A; Passino, K M

1996-01-01

225

Focusing of Relativistic Cooling Jets  

NASA Astrophysics Data System (ADS)

The confinement of a relativistic cooling jet by the pressure and inertia of a surrounding matter is considered. It is demonstrated that, under certain conditions, even modest radiative losses behind the reconfinement shock can lead to a substantial focusing of the jet. The applications to blazars and M87 are discussed. Emphasize is given to the possibility that these recollimation nozzles may be the sources of the highly variable radiation observed in those objects.

Bromberg, Omer; Levinson, Amir

2008-12-01

226

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

227

Focused ion beam direct deposition of gold  

NASA Astrophysics Data System (ADS)

Focused ion beam direct deposition has been developed as a new technique for making patterned metal film directly on substrates. The 20 keV Au(+) ion beam is focused, deflected, and finally decelerated to 30-200 eV between the objective lens and substrate. The decelerated beam is deposited on the substrate at room temperature. The beam diameter can be tuned between 0.5 and 8 microns, and the beam current varies from 40 pA to 10 nA, corresponding to the beam diameter. Current density was about 20 mA/sq cm, so that the deposition rate in the beam spot was estimated about 0.02 micron/s. The purity of gold film was measured with Auger electron spectroscopy, and contents of carbon and oxygen, undesirable impurities, were below detection limits. The resistivity was constant at 3.7 +/- 0.1 microohm cm for deposition over the ion energy range of 34-194 eV.

Nagamachi, Shinji; Yamakage, Yasuhiro; Maruno, Hiromasa; Ueda, Masahiro; Sugimoto, Seiji; Asari, Masatoshi; Ishikawa, Junzo

1993-04-01

228

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

229

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

230

Career Pathways: Focus on Biotechnology  

NSDL National Science Digital Library

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

2009-11-24

231

The quest for customer focus.  

PubMed

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

Gulati, Ranjay; Oldroyd, James B

2005-04-01

232

Line-focus sun trackers  

SciTech Connect

Sun trackers have been a troublesome component for line-focus concentrating collector systems. The problems have included poor accuracy, component failures, false locks on clouds, and restricted tracker operating ranges. In response to these tracking difficulties, a variety of improved sun trackers have been developed. A testing program is underway at SERI to determine the tracking accuracy of this new generation of sun trackers. The three major types of trackers are defined, some recent sun tracker developments are described, and the testing that is underway is outlined.

Gee, R.

1980-05-01

233

Focus Issue: Uncovering Immunological Secrets  

NSDL National Science Digital Library

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

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

2007-08-07

234

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

235

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.

236

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

237

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

238

Plutonium focus area. Technology summary  

SciTech Connect

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

NONE

1997-09-01

239

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

240

Isoelectric focusing technology quantifies protein signaling in 25 cells  

PubMed Central

A previously undescribed isoelectric focusing technology allows cell signaling to be quantitatively assessed in <25 cells. High-resolution capillary isoelectric focusing allows isoforms and individual phosphorylation forms to be resolved, often to baseline, in a 400-nl capillary. Key to the method is photochemical capture of the resolved protein forms. Once immobilized, the proteins can be probed with specific antibodies flowed through the capillary. Antibodies bound to their targets are detected by chemiluminescence. Because chemiluminescent substrates are flowed through the capillary during detection, localized substrate depletion is overcome, giving excellent linearity of response across several orders of magnitude. By analyzing pan-specific antibody signals from individual resolved forms of a protein, each of these can be quantified, without the problems associated with using multiple antibodies with different binding avidities to detect individual protein forms. PMID:17053065

O'Neill, Roger A.; Bhamidipati, Arunashree; Bi, Xiahui; Deb-Basu, Debabrita; Cahill, Linda; Ferrante, Jason; Gentalen, Erik; Glazer, Marc; Gossett, John; Hacker, Kevin; Kirby, Celeste; Knittle, James; Loder, Robert; Mastroieni, Catherine; MacLaren, Michael; Mills, Thomas; Nguyen, Uyen; Parker, Nineveh; Rice, Audie; Roach, David; Suich, Daniel; Voehringer, David; Voss, Karl; Yang, Jade; Yang, Tom; Vander Horn, Peter B.

2006-01-01

241

Micron-focused ion beamlets  

SciTech Connect

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

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

2010-05-15

242

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

243

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.

Aljaz Godec; Ralf Metzler

2015-01-13

244

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

245

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

246

EDITORIAL: Focus on Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

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

2003-09-01

247

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

248

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

249

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

250

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

251

Table detection in heterogeneous documents  

Microsoft Academic Search

Detecting tables in document images is important since not only do tables contain important information, but also most of the layout analysis methods fail in the presence of tables in the document image. Existing approaches for table detection mainly focus on detecting tables in single columns of text and do not work reliably on documents with varying layouts. This paper

Faisal Shafait; Ray Smith

2010-01-01

252

Driver Fatigue Detection: A Survey  

Microsoft Academic Search

Driver fatigue is an important factor in a large number of accidents. There has been much work done in driver fatigue detection. This paper presents a comprehensive survey of research on driver fatigue detection and provides structural categories for the methods which have been proposed. The methods of fatigue detection mainly focused on measures of the driver's state, driver performance

Qiong Wang; Jingyu Yang; Mingwu Ren; Yujie Zheng

2006-01-01

253

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

254

On-chip pumping for pressure mobilization of the focused zones following microchip isoelectric focusing.  

PubMed

Isoelectric focusing (IEF), traditionally accomplished in slab or tube gels, has also been performed extensively in capillary and, more recently, in microchip formats. IEF separations performed in microchips typically use electroosmotic flow (EOF) or chemical treatment to mobilize the focused zones past the detection point. This report describes the development and optimization of a microchip IEF method in a hybrid PDMS-glass device capable of controlling the mobilization of the focused zones past the detector using on-chip diaphragm pumping. The microchip design consisted of a glass fluid layer (separation channels), a PDMS layer and a glass valve layer (pressure connections and valve seats). Pressure mobilization was achieved on-chip using a diaphragm pump consisting of a series of reversible elastomeric valves, where a central diaphragm valve determined the volume of solution displaced while the gate valves on either side imparted directionality. The pumping rate could be adjusted to control the mobilization flow rate by varying the actuation times and pressure applied to the PDMS to actuate the valves. In order to compare the separation obtained using the chip with that obtained in a capillary, a serpentine channel design was used to match the separation length of the capillary, thereby evaluating the effect of diaphragm pumping itself on the overall separation quality. The optimized mIEF method was applied to the separation of labeled amino acids. PMID:17180213

Guillo, Christelle; Karlinsey, James M; Landers, James P

2007-01-01

255

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

256

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

257

The Unfocused Focus Group: Benefit or Bane?  

ERIC Educational Resources Information Center

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

Franz, Nancy K.

2011-01-01

258

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

259

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

260

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

261

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

262

Focusing on Cause or Cure?  

PubMed Central

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

Milner, Lauren C.; Cho, Mildred K.

2013-01-01

263

Motion estimation in ISAR focusing  

NASA Astrophysics Data System (ADS)

Inverse-synthetic aperture radar (ISAR) processing algorithms require an explicit or implicit model of the motion of the target, since this information is not measurable at the sensor. A major unsolved problem is whether it is better to develop a deterministic model of the motion or to fit the observations to a mathematical model which may be ambiguous with a wide range of physical target motions. This question is particularly important for the imaging of small targets in ground clutter since the available information on the target motion may be very limited. By contrast, the imaging of large ships in sea clutter yields a wealth of information of the motion of the body. This paper explores the effectiveness of models of the second kind by testing a set of motion estimation algorithms against motor vehicle targets imaged by a high-frequency SAR at long range and low grazing angle. The algorithms attempt to estimate the bulk motion of the vehicle and its rotation about its mean position by fitting many small pieces of information gathered from low quality or short duration scatterers detected in either the raw range- compressed signal history or in the complex image. In forming the motion model, the algorithm avoids undue reliance on particular bright or narrow-Doppler targets in favor of a global fit to many partially resolved or glinting features. The algorithm is demonstrated for 0.3 meter resolution SAR data of a Winnebago van from a Ku-band radar.

Bennett, John R.; Brown, David S.; Schade, Barton P.; McGlynn, John D.

1997-09-01

264

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

265

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

266

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

267

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

268

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

269

AREA OF FOCUS PETITION Revelle College  

E-print Network

noncontiguous to the major, focused in one department, or focused on one topic from different departments Chemistry & Biochemistry Engineering Mathematics Physics SIO (Earth/Marine Science Minor) Anthropology Minor California Cultures Minor Cognitive Science Critical Gender Studies Environmental Studies Minor

Russell, Lynn

270

Probing nonperturbative QED with optimally focused laser pulses.  

PubMed

We study nonperturbative pair production in intense, focused laser fields called e-dipole pulses. We address the conditions required, such as the quality of the vacuum, for reaching high intensities without initiating beam-depleting cascades, the number of pairs which can be created, and experimental detection of the created pairs. We find that e-dipole pulses offer an optimal method of investigating nonperturbative QED. PMID:23971542

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

2013-08-01

271

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

272

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

273

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

274

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

PubMed Central

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

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

2009-01-01

275

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

PubMed

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

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

2009-10-01

276

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

277

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

278

Do focus measures apply to retinal images?  

NASA Astrophysics Data System (ADS)

The diverse needs for digital auto-focusing systems have driven the development of a variety of focus measures. The purpose of the current study was to investigate whether any of these focus measures are biologically plausible; specifically whether they are applicable to retinal images from which defocus information is extracted in the operation of accommodation and emmetropization, two ocular auto-focusing mechanisms. Ten representative focus measures were chosen for analysis, 6 in the spatial domain and 4 transform-based. Their performance was examined for combinations of non-defocus aberrations and positive and negative defocus. For each combination, a wavefront was reconstructed, the corresponding point spread function (PSF) computed using Fast Fourier Transform (FFT), and then the blurred image obtained as the convolution of the PSF and a perfect image. For each blurred image, a focus measure curve was derived for each focus measure. Aberration data were either collected from 22 real eyes or randomly generated data based on Gaussian parameters describing data from a published large scale human study (n>100). For the latter data set, analyses made use of distributed computing on a small inhomogeneous computer cluster. In the presence of small amounts of nondefocus aberrations, all focus measures showed monotonic changes with positive or negative defocus, and their curves generally remained unimodal, although there were large differences in their variability, sensitivity to defocus and effective ranges. However, the performance of a number of these focus measures became unacceptable when nondefocus aberrations exceed a certain level.

Tian, Yibin; Shieh, Kevin; Wildsoet, Christine F.

2007-02-01

279

Evaluating Exercise Adherence: A Solution Focused Approach .  

E-print Network

??ABSTRACT EVALUATING EXERCISE ADHERENCE: A SOLUTION FOCUSED APPROACH by Jonathan S. Schneider Master of Arts in Psychology: Psychological Science Option California State University, Chico Spring… (more)

Schneider, Jonathan

2011-01-01

280

Outlier-preserving focus+context visualization in parallel coordinates.  

PubMed

Focus+context visualization integrates a visually accentuated representation of selected data items in focus (more details, more opacity, etc.) with a visually deemphasized representation of the rest of the data, i.e., the context. The role of context visualization is to provide an overview of the data for improved user orientation and improved navigation. A good overview comprises the representation of both outliers and trends. Up to now, however, context visualization not really treated outliers sufficiently. In this paper we present a new approach to focus+context visualization in parallel coordinates which is truthful to outliers in the sense that small-scale features are detected before visualization and then treated specially during context visualization. Generally, we present a solution which enables context visualization at several levels of abstraction, both for the representation of outliers and trends. We introduce outlier detection and context generation to parallel coordinates on the basis of a binned data representation. This leads to an output-oriented visualization approach which means that only those parts of the visualization process are executed which actually affect the final rendering. Accordingly, the performance of this solution is much more dependent on the visualization size than on the data size which makes it especially interesting for large datasets. Previous approaches are outperformed, the new solution was successfully applied to datasets with up to 3 million data records and up to 50 dimensions. PMID:17080814

Novotný, Matej; Hauser, Helwig

2006-01-01

281

Auto focus and image registration techniques for infrared imaging of microelectronic devices  

NASA Astrophysics Data System (ADS)

An infrared (IR) microscope camera system is used to measure the temperature distribution of power devices during electrical stress pulses. A calibration is required to correlate the target temperature to the corresponding raw data of the IR camera. The IR microscope camera system contains a fixed lens; this means that the whole camera has to be moved to detect focus images. During the heating up or cooling down process, the thermo-mechanical expansion influences the measurement results. For the calibration of the power device, focus images and a pixel-by-pixel registration of individual images are required. In this paper, methods are discussed to prepare the images for the calibration process. The issues concerning finding the focus image and guaranteeing a pixel-by-pixel overlap in the image sequence are solved and evaluated by the proposed auto focus and the image correlation algorithms. An IR camera equipped with a fixed focus lens is used to perform the measurements; hence, no geometrical distortion occurs. To detect the focus position and corresponding focus image, the principle of passive focusing is used, where a focus curve is recorded. Different methods are discussed to compute the focus value. Image registration is applied to compute the distortion between the images and guarantee a pixel-by-pixel overlap. In our case, the most significant parameter is the displacement; hence, the SIFT algorithm of Lowe and a simple image correlation algorithm are implemented and compared.

Florian, Daniela; Köck, Helmut; Plankensteiner, Kathrin; Glavanovics, Michael

2013-07-01

282

Prostate focused ultrasound focal therapy--imaging for the future.  

PubMed

Treatment of prostate cancer using high-intensity focused ultrasound (HIFU) focal therapy will become a reliable treatment option only if several conditions are fulfilled. These conditions concern patient selection, assessment of the tumour location and aggressiveness, evaluation of target tissue destruction, and detection of local recurrence or appearance of new tumours. Regarding patient selection, standard transrectal biopsies are not accurate enough and, although perineal template biopsies can detect tumours, they are invasive, expensive procedures, and there is a risk of incidental detection of insignificant cancers. In turn, multiparametric MRI is accurate for detecting and localizing high-grade (Gleason score ?7) cancers and may provide non-invasive assessment of tumour aggressiveness. Moreover, contrast-enhanced imaging-ultrasonography or MRI-can assess post-HIFU tissue destruction and provide accurate detection of tumour recurrence, which is a key element for follow up. This Perspectives article will assess whether our current methods for cancer diagnosis, tissue targeting, and treatment follow up are accurate enough to allow the design of robust HIFU focal therapy protocols. PMID:22910682

Rouvière, Olivier; Gelet, Albert; Crouzet, Sébastien; Chapelon, Jean-Yves

2012-12-01

283

Harm reduction and individually focused alcohol prevention  

Microsoft Academic Search

This paper provides a brief overview of harm reduction and individually focused alcohol prevention strategies. Universal, selective, and indicated prevention strategies are described for several populations including elementary and secondary schools, colleges, and medical settings. This paper primarily reviews individually focused alcohol prevention efforts in the United States (US), where harm reduction has been less well received in comparison to

Clayton Neighbors; Mary E. Larimer; Ty W. Lostutter; Briana A. Woods

2006-01-01

284

Focused Monitoring. Alliance Action Information Sheets  

ERIC Educational Resources Information Center

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

Technical Assistance ALLIANCE for Parent Centers, 2005

2005-01-01

285

Seismic Migration For Sar Focusing: Interferometrical Applications  

Microsoft Academic Search

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

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

1990-01-01

286

Angelo Tsagarakis Business Academic focus International Marketing  

E-print Network

Academic achievement Pac-10 All-Academic squad,honorable mention > Volunteerism and leadership MotivationalAngelo Tsagarakis Business Academic focus International Marketing "I use basketball as a metaphor focused The music of French rapper Booba and other hip-hop artists helps me visualize and get in the zone

Escher, Christine

287

Teaching Focus Group Interviewing: Benefits and Challenges  

ERIC Educational Resources Information Center

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

George, Molly

2013-01-01

288

Focus Group Research: Procedures and Pitfalls.  

ERIC Educational Resources Information Center

Focus group research, which involves the exploration of a carefully selected research question by a group of homogeneous subjects, is a qualitative research tool which seems to be a quick and easy means of staying abreast of the educational needs and expectations of community colleges. However, it is difficult to moderate focus groups and…

Cohen, Marlene C.; Engleberg, Isa N.

289

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

290

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

291

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

292

Inclusive Focus Particles in English and Korean  

ERIC Educational Resources Information Center

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

Kang, Sang-gu

2011-01-01

293

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

294

Focusing One's Microscope By Daniel Pauly  

E-print Network

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

Pauly, Daniel

295

Attentional Focusing Instructions and Force Production  

PubMed Central

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

Marchant, David C.

2010-01-01

296

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

297

Fusing images with different focuses using support vector machines.  

PubMed

Many vision-related processing tasks, such as edge detection, image segmentation and stereo matching, can be performed more easily when all objects in the scene are in good focus. However, in practice, this may not be always feasible as optical lenses, especially those with long focal lengths, only have a limited depth of field. One common approach to recover an everywhere-in-focus image is to use wavelet-based image fusion. First, several source images with different focuses of the same scene are taken and processed with the discrete wavelet transform (DWT). Among these wavelet decompositions, the wavelet coefficient with the largest magnitude is selected at each pixel location. Finally, the fused image can be recovered by performing the inverse DWT. In this paper, we improve this fusion procedure by applying the discrete wavelet frame transform (DWFT) and the support vector machines (SVM). Unlike DWT, DWFT yields a translation-invariant signal representation. Using features extracted from the DWFT coefficients, a SVM is trained to select the source image that has the best focus at each pixel location, and the corresponding DWFT coefficients are then incorporated into the composite wavelet representation. Experimental results show that the proposed method outperforms the traditional approach both visually and quantitatively. PMID:15565781

Li, Shutao; Kwok, James Tin-Yau; Tsang, Ivor Wai-Hung; Wang, Yaonan

2004-11-01

298

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

299

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

NASA Astrophysics Data System (ADS)

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

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

2008-02-01

300

Laser focus compensating sensing and imaging device  

DOEpatents

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

Vann, Charles S. (Fremont, CA)

1993-01-01

301

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

302

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

303

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

304

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

305

Focused Ion beam source method and Apparatus  

SciTech Connect

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.; Lykke, Keith R.; Lill, Thorsten B.

1998-08-17

306

Focused auditory attention and frequency selectivity  

Microsoft Academic Search

The probe-signal method (Greenberg & Larkin, 1968) was used to determine the percentage of trials in which unpracticed subjects\\u000a detected (two-interval, forced-choice) a soft, expected sound as compared with an unexpected sound. Pure tones at or near\\u000a an expected frequency were detected in about 90% of the trials. Tones more than one-half critical band away were detected\\u000a near chance (50%).

Bertram Scharf; S. Quigley; C. Aoki; N. Peachey; A. Reeves

1987-01-01

307

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

308

Periodic magnetic focusing of sheet electron beams  

SciTech Connect

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

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

1994-05-01

309

Focusing Internet Searches for World Music Resources  

ERIC Educational Resources Information Center

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

Mishra, Jennifer

2004-01-01

310

The plasma focus as a thruster  

E-print Network

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

Hardy, Richard Lee

2005-02-17

311

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

312

Nonlinear electrophoretic focusing of DNA macromolecules.  

PubMed

A new approach to focusing DNA molecules in a nonuniform electric field based on nonlinear mobility (L. L. Frumin, S. E. Peltek, S. Bukshpan, V. V. Chasovskikh and G. V. Zilberstein, PhysChemComm, 2000, 11) is proposed. The focusing is carried out in an alternating nonuniform electric field, created by using a wedge gel with hyperbolic boundaries. Methods of the theory of analytical functions were used to demonstrate that the fractions separated electrophoretically in such a wedge retain their rectilinear shape. Solutions for the focusing points for the case of mere velocity cubic nonlinearity were obtained as well as for the square velocity nonlinearity, suggested in a number of modern approaches. Gel electrophoresis experiments supported the possibility of a pronounced nonlinear focusing of DNA molecules. This nonlinear separation technique presents encouraging prospects for preparative isolation of long DNA fragments and development of new separation methods for bacterial fingerprinting. PMID:11394292

Frumin, L L; Peltek, S E; Zilberstein, G V

2001-05-01

313

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

314

Raman self-focusing at maximum coherence  

NASA Astrophysics Data System (ADS)

We demonstrate a type of Raman self-focusing and -defocusing that is inherent in operation at maximum coherence. In this regime the two-photon detuning from the Raman resonance controls the refractive index of the medium.

Walker, D. R.; Yavuz, D. D.; Shverdin, M. Y.; Yin, G. Y.; Sokolov, A. V.; Harris, S. E.

2002-12-01

315

Hydrodynamic focusing of a particle flux  

SciTech Connect

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

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

1995-12-01

316

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

317

Focus group research and "the patient's view".  

PubMed

A clear emphasis on the patient's view is discernible in the health services research literature of the past decades. Such a switch to patients' perspectives has been greatly facilitated by a wider acceptance and use of qualitative methods. In particular, focus groups are often used to uncover the range and depth of experiences of health services users and chronically ill individuals. Although this method contributes to a better understanding of patients' perspectives and practices, a number of analytical considerations have been overlooked. The aim of this paper is to consider how to conceptualise and analyse interactions in focus group research. We argue that focus groups are social spaces in which participants co-construct the "patient's view" by sharing, contesting and acquiring knowledge. Focus groups conducted with home care patients in Quebec, Canada (on antibiotic intravenous therapy, parenteral nutrition, peritoneal dialysis and oxygen therapy) are used to illustrate three interactive processes at work in focus groups: (1) establishing oneself as experienced and knowledgeable; (2) establishing oneself as in search of information and advice; and (3) validating or challenging one another's knowledge claims. We develop an analytical template focused on the subtle dynamics underpinning the various and at times competing claims of patients. This template acknowledges the processes through which participants attribute authority to the claims of others, including the focus group moderator. We find that focus group research does not derive epistemological authority simply from the identity of its participants. Rather, an emerging consensus about what constitutes the patient's view is the result of context-dependent social interactions that need to be scrutinised. PMID:16797811

Lehoux, Pascale; Poland, Blake; Daudelin, Genevieve

2006-10-01

318

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

319

Integrated micro focusing and tracking sensor  

NASA Astrophysics Data System (ADS)

We have developed an integrated optical tracking and focusing sensor, which is a chip 1 mm by 0.5 mm. It can travel along guide patterns keeping a certain gap between itself and the guide pattern. It consists of a laser diode, monolithically fabricated photodiodes and microlenses having a graded refractive index distribution in the thickness direction. Experimental results showed that this integrated sensor can be used as a focusing and tracking sensor with sub-micron accuracy.

Sawada, R.; Shimada, J.; Higurashi, E.; Ito, T.

1999-03-01

320

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

321

EXPLOSIVES DETECTION: A Challenge for Physical Chemistry  

Microsoft Academic Search

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

Jeffrey I. Steinfeld; Jody Wormhoudt

1998-01-01

322

The DEMIAN system approach to intrusion detection  

Microsoft Academic Search

This paper presents a small multi-agent system for intrusion detection, the DE- MIAN system, which contributes with a new knowledge specification approach to model the be- haviour and the communication of intrusion detection agents. A new detection language, with special focus on simplicity, usability and maintenance, was specified to model DEMIAN moni- toring agents. A new correlation language, with a

João Carlos Gluz; Rosa Maria Viccari; Josué Klafke Sperb

2003-01-01

323

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

ERIC Educational Resources Information Center

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

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

2011-01-01

324

Focus-distance-controlled 3D TV  

NASA Astrophysics Data System (ADS)

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

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

1996-09-01

325

Focus-distance-controlled 3D TV  

NASA Astrophysics Data System (ADS)

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

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

1997-05-01

326

Detective Fiction  

E-print Network

Broadcast Transcript: Detective fiction in the West celebrates its 100th anniversary this year. Of course, the detective genre has been around for way longer here in China. The Casebook of Judge Dee was written about 300 ...

Hacker, Randi; Schrock, John Richard; Tsutsui, William

2006-07-12

327

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

328

High-efficiency capillary isoelectric focusing of peptides.  

PubMed

Several approaches are presently being developed for global proteome characterization that are based upon the analysis of polypeptide mixtures resulting from digestion of (often complex) mixtures of proteins. Improved methods for peptide analysis are needed that provide for sample concentration, higher resolution separations, and direct compatibility with mass spectrometry. In this work, methods for the high-efficiency capillary isoelectric focusing (CIEF) separation of peptides have been developed that provide for simultaneous sample concentration and separation according to peptide isoelectric point. Under typical nondenaturing CIEF conditions, peptides are concentrated approximately 500-fold, and peptides present at < 1 ng/ microL were detectable using conventional UV detection. CIEF separations of peptides provided much faster measurements of isoelectric points compared with conventional isoelectric focusing in gels. Very small differences in peptide isoelectric points (deltapI approximately 0.01) could be resolved, High-efficiency CIEF separations for complex peptide mixtures from tryptic digestion of yeast cytosol fractions were obtained and showed significant improvement over those obtained using capillary zone electrophoresis and packed capillary reversed-phase liquid chromatography. PMID:10815979

Shen, Y; Berger, S J; Anderson, G A; Smith, R D

2000-05-01

329

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

330

Capillary isoelectric focusing-electrospray mass spectrometry for protein analysis  

SciTech Connect

On-line combination of capillary isoelectric focusing (CIEF) with electrospray mass spectrometry (ESMS) as a two-dimensional separation system is demonstrated. Mixtures of model proteins including cytochrome c (horse heart), myoglobin (horse heart), and carbonic anhydrase II (bovine erythrocyte) are focused and cathodically mobilized in a polyacrylamide-coated capillary. At the end of CIEF capillary, the mobilized protein zones are analyzed by mass spectrometry coupled on-line to an electrospray interface with a coaxial sheath flow configuration. The effects of carrier ampholyte concentration on the CIEF separation and the protein electrospray ionization mass spectra are presented and discussed. In this study, the focusing effect of CIEF permits analysis of very dilute protein samples. A typical concentration factor of 50-100 times is observed. The concentration detection limit of myoglobin for a full-scan CIEF-ESMS analysis is in the range of 10{sup -7} M, 2 orders of magnitude over that possible with normal capillary zone electrophoresis ESMS. 35 refs., 5 figs., 2 tabs.

Tang, Q.; Harrata, A.K.; Lee, C.S. [Ames Lab., IA (United States)

1995-10-01

331

High Resolution Double-Focusing Isotope Ratio Mass Spectrometry  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

332

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

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

333

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

334

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

335

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

336

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

337

Tightly focused, ultrafast TM01 laser pulses  

NASA Astrophysics Data System (ADS)

Nowadays, the generation of laser pulses focused to a spot size comparable to the wavelength and whose duration is only a few optical cycles of the electric field is achievable. Moreover, TM01 laser pulses are of considerable interest, among other things, because of their remarkable focusing properties. In order to describe theoretically the spatiotemporal behaviour of such nonparaxial, ultrashort TM01 pulses, one needs expressions of their electromagnetic fields. To obtain these expressions, Maxwell's equations must be solved rigorously. The method of the Hertz potential, the complex-source/sink model, and the use of a Poisson-like spectrum are exploited to solve the vectorial wave equation. Closed-form expressions for the electric and the magnetic fields of an isodiffracting TM01 pulse are presented and they can be used to study the behaviour of tightly focused, ultrafast TM pulses.

April, Alexandre

2009-06-01

338

Focus issue introduction: space-division multiplexing.  

PubMed

Since the publication of the first focus issue [Opt. Express 19(11), 2011], single-fiber transmission capacity has eclipsed the 1 Pb/s mark. All aspects related to space-division multiplexing including fiber, passive components [(de)multiplexer, couplers], active components (EDFA and Raman amplifiers), switching and routing elements (ROADM and WSS), as well as transmission and networking have progressed rapidly. This focus issue is intended to bring together the most up-to-date research in space-division multiplexing, including fibers, passive and active components, transmission systems and networking. PMID:25607215

Li, Guifang; Karlsson, Magnus; Liu, Xiang; Quiquempois, Yves

2014-12-29

339

A novel microfluidic flow focusing method.  

PubMed

A new microfluidic method that allows hydrodynamic focusing in a microchannel with two sheath flows is demonstrated. The microchannel network consists of a T-shaped main channel and two T-shaped branch channels. The flows of the sample stream and the sheath streams in the microchannel are generated by electroosmotic flow-induced pressure gradients. In comparison with other flow focusing methods, this novel method does not expose the sample to electrical field, and does not need any external pumps, tubing, and valves. PMID:25538810

Jiang, Hai; Weng, Xuan; Li, Dongqing

2014-09-01

340

Automation support of patient-focused care.  

PubMed

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

Thielke, T S

1994-04-01

341

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

342

Fast isoelectric focusing of milk proteins on small ultrathin polyacrylamide gels containing urea.  

PubMed

The preparation of 0.45 mm thin polyacrylamide gels, containing urea, for horizontal micro isoelectric focusing of milk proteins with PhastSystem is described. Isoelectric focusing in the small gels, stained either with Coomassie Brilliant Blue R-250 or with the more sensitive silver stain, affords a fast and sensitive procedure for an analysis of milk and cheese proteins. The procedure can be effectively exploited in detecting adulteration in ovine cheese with bovine milk. PMID:2776737

Moio, L; Di Luccia, A; Addeo, F

1989-07-01

343

[Cavitation and boiling of bubbles at the focal region during high intensity focused ultrasound exposure].  

PubMed

High intensity focused ultrasound (HIFU) is a very complex transient process and can cause tissue coagulation necrosis. The cavitation and boiling behaviour of bubbles in the focal region play very important roles throughout an injury process. This paper reviews the research done by domestic and foreign scholars on behaviours of bubbles in HIFU irradiation process and summarizes in the focal region bubble cavitation and boiling generation, related detective means and relationships with hyperecho, temperature rise of the focus and injury shape. PMID:23198445

Zhong, Mingsong; Ai, Huijian; Li, Faqi

2012-10-01

344

3D face detection using curvature analysis  

Microsoft Academic Search

Face detection is a crucial preliminary in many applications. Most of the approaches to face detection have focused on the use of two-dimensional images. We present an innovative method that combines a feature-based approach with a holistic one for three-dimensional (3D) face detection. Salient face features, such as the eyes and nose, are detected through an analysis of the curvature

Alessandro Colombo; Claudio Cusano; Raimondo Schettini

2006-01-01

345

Flat dielectric grating reflectors with focusing abilities  

E-print Network

mirrors have been used to replace the top dielectric stacks in vertical-cavity surface-emitting lasersFlat dielectric grating reflectors with focusing abilities David Fattal*, Jingjing Li, Zhen Peng laser cavities to CD/DVD read/write heads. Resonant effects in dielectric gratings were first clearly

Li, Jingjing

346

Focusing Solenoids for the Mice Cooling Channel  

SciTech Connect

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

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

2004-06-23

347

Generating Alternatives: Interpreting Focus in Discourse  

ERIC Educational Resources Information Center

This dissertation investigates a class of context-dependent expressions--focus-sensitive particles--as a way of addressing how language users draw on contextual information to interpret expressions whose meanings are underdetermined by their forms. While the problem of context dependence has been widely studied, the question of precisely what…

Kim, Christina S.

2012-01-01

348

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

349

Focus on the Question for Intermediate Algebra.  

ERIC Educational Resources Information Center

Focusing on the question that is being discussed in a mathematics lesson is suggested as an approach to teaching developmental mathematics at the college level. Ways in which students can be involved with the question are described. First, some contagious cliches that are used by students are given. Then a few antidotal aphorisms and educational…

Feldman, Leonard

350

A focusing gas scintillation proportional counter  

NASA Technical Reports Server (NTRS)

An improved large-area gas scintillation proportional counter has been built, suitable for use in X-ray astronomy. This counter employs electron focusing in a drift region to achieve uniform response. It is shown that a window area of 60 sq cm and a spectral resolution of 10% fwhm or better at 5.9 keV can be obtained.

Anderson, D. F.; Bodine, O. H.; Novick, R.; Wolff, R. S.

1977-01-01

351

Practitioner-Focused Degrees in Politics  

ERIC Educational Resources Information Center

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

Craig, John

2010-01-01

352

SAR data focusing using seismic migration techniques  

Microsoft Academic Search

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

Ciro Cafforio; Claudio Prati; Fabio Rocca

1991-01-01

353

California Program Focuses on School Readiness  

ERIC Educational Resources Information Center

California State University, Long Beach, in collaboration with Long Beach Unified School District's Head Start and Child Development Centers, and the community childcare agency Young Horizons implemented an intervention and evaluation program to improve children's school readiness. The focus of Readiness and Early Activities for Children from the…

Stanley, M. Sue

2004-01-01

354

Beam hysteresis via reorientational self-focusing.  

PubMed

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

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

2014-10-15

355

NURSE ROSTERING Focus on models or  

E-print Network

NURSE ROSTERING Focus on models or algorithms? Greet Vanden Berghe KU Leuven CHOIR in Practice, 22 November 2013 Greet Vanden Berghe - Nurse rostering 1/53 #12;Taxonomy personnel rostering A.T. Ernst et al), Personnel scheduling: A literature review Greet Vanden Berghe - Nurse rostering 2/53 #12;Definition Nurse

Al Hanbali, Ahmad

356

Focus Issue: Signals for Gene Expression  

NSDL National Science Digital Library

This Focus Issue of Science Signaling complements the Science Special Issue on Epigenetics (http://www.sciencemag.org/special/epigenetics/) with articles describing gene regulatory events. Highlights include signaling pathways that alter epigenetic patterning, transcriptional network organization, and posttranscriptional regulation of signaling molecules by microRNAs.

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

2010-11-02

357

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

358

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

359

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

360

Conceptions of Limited Attention and Discourse Focus  

Microsoft Academic Search

Walker (1996) presents a cache model of the operation of attention in the processing of discourse as an alternative to the focus space stack that was proposed previously by Grosz and Sidner (Grosz 1977a; Grosz and Sidner 1986). In this squib, we present a critical analysis of the cache model and of Walker's supporting evidence from anaphora in discourses with

Barbara J. Grosz; Peter C. Gordon

1999-01-01

361

External Resource: Earth Science: Focus Areas  

NSDL National Science Digital Library

This resource provides links to the focus areas of the presence of carbon-based life; water in multiple, interacting phases; a fluid atmosphere and ocean that redistribute heat over the planetary surface; an oxidizing and protective atmosphere; a solid bu

1900-01-01

362

Focusing antennas usage in locating acoustic sources  

Microsoft Academic Search

The signal treatment techniques and performance data for a focusing antenna composed of a linear array of acoustic elements used to localize acoustic sources in a wind tunnel are described. It is assumed that the sound waves propagate in a spherical mode, and account is taken of the effects of refraction and convection. The model assumes a monopolar source, and

G. Elias; C. Malarmey

1983-01-01

363

Automatic dynamic depth focusing for NDT  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

364

Focusing of Rayleigh waves: simulation and experiments.  

PubMed

A linear array of surface wave transducers has been developed to generate focused surface wave motion. A novel theoretical approach, whereby time-harmonic surface wave motion is represented by a carrier wave that satisfies a reduced wave equation on the surface of the body and supports the subsurface motion, is used to model the beam generated by a single element of the array. Comparison of theoretical and experimental results show that, for a single element, the opening angle of the beam is about 20 degrees and its cross-section can be represented by a Gaussian distribution of the normal displacements. For an eight-element array, the focused beam is subsequently obtained by superposition considerations. For the focused beam comparisons of theoretical and experimental results, in which the latter have been obtained by the use of a laser interferometer, show excellent agreement both for the normal displacements along a radial line and across the width of the beam. The array can be used for self-focusing of surface waves on a surface defect. PMID:18238429

Deutsch, W K; Cheng, A; Achenbach, J D

1999-01-01

365

Focus: Composition: Old Problems, New Alternatives.  

ERIC Educational Resources Information Center

The three articles in this journal issue focus on composition problems and alternatives. The topics discussed are compositional invention, composition based on students' experiences, and an oral technique for teaching basic composition. The issue also contains reviews of recent publications in the field of composition. (FL)

Stewart, Donald, Ed.

1978-01-01

366

Research Focus Stress hormones and mate choice  

E-print Network

the interactions among glucocor- ticoid stress hormones, sex steroids and body condition. Stress hormones during periods when stress could affect sexually selected traits. In birds, the stress response canResearch Focus Stress hormones and mate choice Jerry F. Husak and Ignacio T. Moore Department

Husak, Jerry F.

367

FOCUS REVIEW Control of extracellular microenvironments using  

E-print Network

microenvironment (Scheme 1).1 The extracellular microenvironment is a hydrated protein and proteoglycan-based ECM of substrates such as mica and glass into aqueous solutions of positively and negatively charged polymersFOCUS REVIEW Control of extracellular microenvironments using polymer/protein nanofilms

Cai, Long

368

Content-Focused Coaching: Transforming Mathematics Lessons.  

ERIC Educational Resources Information Center

Content-Focused Coaching (CFC) is a long-range professional development practice in which coaches work individually or with groups of classroom teachers to design, implement, and reflect on rigorous, standards-based lessons that promote student learning. This book is for K-8 staff developers, teacher leaders, administrators, and others interested…

West, Lucy; Staub, Fritz C.

369

Focus Issue: Getting Excited About Glia  

NSDL National Science Digital Library

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

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

2010-11-09

370

TECHNICAL INTEGRATION ENVIRONMENTAL MANAGEMENT FOCUS AREAS  

Microsoft Academic Search

This contract involved a team of companies led by WPI (formerly the Waste Policy Institute). In addition to WPI, the team included four subcontractors--TRW (formerly BDM Federal), SAIC, Energetics, and the University of North Dakota Energy and Environmental Research Center (EERC). The team of companies functioned as a ''seamless team'' assembled to support the Environmental Management Program Focus Areas. Staff

Carey R. Butler

2001-01-01

371

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

372

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

373

Focus Article Beetle horns and horned beetles  

E-print Network

Focus Article Beetle horns and horned beetles: emerging models in developmental evolution of horned beetles and beetle horns as study systems amenable to the integration of a wide range evolution. For each question we discuss how work on horned beetles is contributing to our current

Moczek, Armin P.

374

Focus Article Linking genome to epigenome  

E-print Network

Focus 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-resolution maps of the entire epigenome which can be compared to gain functional insights. Significant differences

Yuan, Guo-Cheng "GC"

375

What is ANTS? Focuses on those students  

E-print Network

What is ANTS? · Focuses on those students: · Returning to college after an interruption · Starting their college education later in life · Pursuing a career change · Juggling the demands of work- smoking facility. 3. No sleeping overnight or otherwise living in the office space is allowed. 4

New Mexico, University of

376

Policy message A narrow focus on conventional  

E-print Network

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

Richner, Heinz

377

IN-FOCUSIN-FOCUS Letters&Science  

E-print Network

as an art lover and passionate advocate for art education and appreciation." Mathis began collecting art2012August IN-FOCUSIN-FOCUS Letters&Science A multimillion-dollar gift to the UWM Art Collection that will benefit both students and the community will be celebrated September 6 with the opening of "Rembrandt

Saldin, Dilano

378

Children's Comprehension of Sentences with Focus Particles.  

ERIC Educational Resources Information Center

Three studies investigated the comprehension of sentences containing the focus particle "only" by children and adults. Contrary to previous findings, two of the studies found that young children made errors predominantly by failing to process contrast information rather than errors in which they failed to use syntactic information to restrict the…

Paterson, Kevin B.; Liversedge, Simon P.; Rowland, Caroline; Filik, Ruth

2003-01-01

379

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

380

SPECIAL FOCUS CURRENT SCIENCE, 2013 7  

E-print Network

on drought seldom move the focus away from the human tragedy to the hydrology of the region. Travel writing impact imme- diate. A better gadget, a new health treatment, an environment-friendly car, a robot that can cook. The products of technology ­ no matter how outlandish ­ are guaranteed human interest

Joshi, Yogesh Moreshwar

381

Focus. Volume 26, Number 2, Fall 2009  

ERIC Educational Resources Information Center

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

Caspar, Emma, Ed.

2009-01-01

382

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

383

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

384

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

385

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

386

Customer-focused planning: Demonstration project summaries  

SciTech Connect

To succeed in the increasingly competitive and dynamic markets in which they operate, electric utilities are focusing ever greater attention on understanding and meeting customer needs. EPRI's Customer Focused Planning (CFP) project was established to develop concepts and tools that will help utilities enhance their commitment to customer service. The project team conducted a series of interviews and meetings with participating utilities to collaboratively implement crucial steps in the CFP process. Although there is no unique set of tools or single management approach for improving product and service delivery, customer-focused companies have at least five ideals in common. They (1) define goals and objectives in concrete terms, (2) extend the planning boundaries of the organization to include all members of the energy services infrastructure, (3) painstakingly link functional activities directly to customer needs, (4) incorporate the customer's voice in new product/ service design, and (5) align performance measures with customer needs. In addition, customer-focused companies use a variety of methods to improve customer satisfaction and company performance. These methods include conducting market research, developing market processes such as demand-side management contracting or bidding to reveal customer preferences, and involving customers more directly in the planning process. This report summarizes two brief demonstration projects conducted as part of EPRI's CFP project, one at Commonwealth Edison Company (CECo) and one at PSI Energy. The CECo project emphasized developing customer-focused performance measures for telephone inquiries. The PSI Energy project involved a one-day workshop underscoring two important CFP elements-understanding customer wants and explicitly linking those wants to utility activities.

George, S.S. (Putnam, Hayes and Bartlett, Inc., San Francisco, CA (United States))

1992-12-01

387

Comprehensive volumetric confocal microscopy with adaptive focusing  

PubMed Central

Comprehensive microscopy of distal esophagus could greatly improve the screening and surveillance of esophageal diseases such as Barrett’s esophagus by providing histomorphologic information over the entire region at risk. Spectrally encoded confocal microscopy (SECM) is a high-speed reflectance confocal microscopy technology that can be configured to image the entire distal esophagus by helically scanning the beam using optics within a balloon-centering probe. It is challenging to image the human esophagus in vivo with balloon-based SECM, however, because patient motion and anatomic tissue surface irregularities decenter the optics, making it difficult to keep the focus at a predetermined location within the tissue as the beam is scanned. In this paper, we present a SECM probe equipped with an adaptive focusing mechanism that can compensate for tissue surface irregularity and dynamic focal variation. A tilted arrangement of the objective lens is employed in the SECM probe to provide feedback signals to an adaptive focusing mechanism. The tilted configuration also allows the probe to obtain reflectance confocal data from multiple depth levels, enabling the acquisition of three-dimensional volumetric data during a single scan of the probe. A tissue phantom with a surface area of 12.6 cm2 was imaged using the new SECM probe, and 8 large-area reflectance confocal microscopy images were acquired over the depth range of 56 ?m in 20 minutes. Large-area SECM images of excised swine small intestine tissue were also acquired, enabling the visualization of villous architecture, epithelium, and lamina propria. The adaptive focusing mechanism was demonstrated to enable acquisition of in-focus images even when the probe was not centered and the tissue surface was irregular. PMID:21698005

Kang, DongKyun; Yoo, Hongki; Jillella, Priyanka; Bouma, Brett E.; Tearney, Guillermo J.

2011-01-01

388

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

PubMed

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

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

1992-01-01

389

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

390

Micro flow cytometer with self-aligned 3D hydrodynamic focusing  

PubMed Central

A micro flow cytometer with a single step 3D hydrodynamic flow focusing has been developed. The proposed design is capable to create a single-file particle stream that is self-aligned with an integrated optical fiber-based detection system, regardless of the flow rate ratio between the focusing and core liquids. The design approach provides the ability to adjust the stream size while keeping the position of the focused stream centered with respect to the focusing channel. The device has been fabricated by direct micro milling of PMMA sheets. Experimental validation of the hydrodynamic sheath focusing effect has been presented and sample stream with tuneable size from about 18 to 50 ?m was measured. Flow cytometry measurements have been performed by using 10-23 ?m fluorescent particles. From the analysis of the signals collected at each transit event we can confirm that the device was capable to align and measure microparticles with a good coefficient of variance.

Testa, Genni; Persichetti, Gianluca; Bernini, Romeo

2014-01-01

391

Editorial Focus What Makes Whiskers Shake? Focus on "Current Flow in Vibrissa Motor  

E-print Network

-pattern-generator" (Gao et al. 2001). Finally, earlier unit-recording studies in vibrissa motor cortex (Carvell et alEditorial Focus What Makes Whiskers Shake? Focus on "Current Flow in Vibrissa Motor Cortex Can. Such simplicity makes whisking an attractive model for the study of motor control. In this issue (p. 1700

Kleinfeld, David

392

EDITORIAL: Focus on the neural interface Focus on the neural interface  

NASA Astrophysics Data System (ADS)

The possibility of an effective connection between neural tissue and computers has inspired scientists and engineers to develop new ways of controlling and obtaining information from the nervous system. These applications range from `brain hacking' to neural control of artificial limbs with brain signals. Notwithstanding the significant advances in neural prosthetics in the last few decades and the success of some stimulation devices such as cochlear prosthesis, neurotechnology remains below its potential for restoring neural function in patients with nervous system disorders. One of the reasons for this limited impact can be found at the neural interface and close attention to the integration between electrodes and tissue should improve the possibility of successful outcomes. The neural interfaces research community consists of investigators working in areas such as deep brain stimulation, functional neuromuscular/electrical stimulation, auditory prostheses, cortical prostheses, neuromodulation, microelectrode array technology, brain-computer/machine interfaces. Following the success of previous neuroprostheses and neural interfaces workshops, funding (from NIH) was obtained to establish a biennial conference in the area of neural interfaces. The first Neural Interfaces Conference took place in Cleveland, OH in 2008 and several topics from this conference have been selected for publication in this special section of the Journal of Neural Engineering. Three `perspectives' review the areas of neural regeneration (Corredor and Goldberg), cochlear implants (O'Leary et al) and neural prostheses (Anderson). Seven articles focus on various aspects of neural interfacing. One of the most popular of these areas is the field of brain-computer interfaces. Fraser et al, report on a method to generate robust control with simple signal processing algorithms of signals obtained with electrodes implanted in the brain. One problem with implanted electrode arrays, however, is that they can fail to record reliably neural signals for long periods of time. McConnell et al show that by measuring the impedance of the tissue, one can evaluate the extent of the tissue response to the presence of the electrode. Another problem with the neural interface is the mismatch of the mechanical properties between electrode and tissue. Basinger et al use finite element modeling to analyze this mismatch in retinal prostheses and guide the design of new implantable devices. Electrical stimulation has been the method of choice to activate externally the nervous system. However, Zhang et al show that a novel dual hybrid device integrating electrical and optical stimulation can provide an effective interface for simultaneous recording and stimulation. By interfacing an EMG recording system and a movement detection system, Johnson and Fuglevand develop a model capable of predicting muscle activity during movement that could be important for the development of motor prostheses. Sensory restoration is another unsolved problem in neural prostheses. By developing a novel interface between the dorsal root ganglia and electrodes arrays, Gaunt et al show that it is possible to recruit afferent fibers for sensory substitution. Finally, by interfacing directly with muscles, Jung and colleagues show that stimulation of muscles involved in locomotion following spinal cord damage in rats can provide an effective treatment modality for incomplete spinal cord injury. This series of articles clearly shows that the interface is indeed one of the keys to successful therapeutic neural devices. The next Neural Interfaces Conference will take place in Los Angeles, CA in June 2010 and one can expect to see new developments in neural engineering obtained by focusing on the neural interface.

Durand, Dominique M.

2009-10-01

393

Focused fluid flow in passive continental margins.  

PubMed

Passive continental margins such as the Atlantic seaboard of Europe are important for society as they contain large energy resources, and they sustain ecosystems that are the basis for the commercial fish stock. The margin sediments are very dynamic environments. Fluids are expelled from compacting sediments, bottom water temperature changes cause gas hydrate systems to change their locations and occasionally large magmatic intrusions boil the pore water within the sedimentary basins, which is then expelled to the surface. The fluids that seep through the seabed at the tops of focused fluid flow systems have a crucial role for seabed ecology, and study of such fluid flow systems can also help in predicting the distribution of hydrocarbons in the subsurface and deciphering the climate record. Therefore, the study of focused fluid flow will become one of the most important fields in marine geology in the future. PMID:16286294

Berndt, Christian

2005-12-15

394

Atomic focusing by quantum fields: Entanglement properties  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

395

Focused-laser interferometric position sensor  

SciTech Connect

We describe a simple method to measure the position shifts of an object with a range of tens of micrometers using a focused-laser (FL) interferometric position sensor. In this article we examine the effects of mechanical vibration on FL and Michelson interferometers. We tested both interferometers using vibration amplitudes ranging from 0 to 20 {mu}m. Our FL interferometer has a resolution much better than the diffraction grating periodicities of 10 and 14 {mu}m used in our experiments. A FL interferometer provides improved mechanical stability at the expense of spatial resolution. Our experimental results show that Michelson interferometers cannot be used when the vibration amplitude is more than an optical wavelength. The main purpose of this article is to demonstrate that a focused-laser interferometric position sensor can be used to measure the position shifts of an object on a less sensitive, micrometer scale when the vibration amplitude is too large to use a Michelson interferometer.

Friedman, Stephen J.; Barwick, Brett; Batelaan, Herman [Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0111 (United States)

2005-12-15

396

Respect redefined: focus group insights from Singapore.  

PubMed

This article re-examines the meaning of the concept of respect within the context of a fast modernizing Asian multicultural society-Singapore. Two key findings emerge. First, the meaning of respect both from the perspective of the aged and the middle-aged generation has shifted from obedience to courteous behavior. Second, in the majority of focus groups members concurred that the degree of respect accorded to elders has in general decreased. The focus group methodology was used in this research. Bearing in mind the limited sample size (88 participants) these findings alert us to the need for social scientists to monitor perceptual shifts in meaning of concepts critical in the sphere of interpersonal relationships. The findings throw light on the subjective views of intergenerational relations within the family as well as the community. As such, they would be valuable to counselors, social workers, and family therapists. PMID:9248879

Mehta, K

1997-01-01

397

Subdiffraction Focusing Enabled by a Fano Resonance  

NASA Astrophysics Data System (ADS)

Radiationless electromagnetic interference (REI) has been used to achieve focusing below Abbe's diffraction limit. Here, we demonstrate an approach to REI that uses the Fano resonance of subwavelength slits to achieve subdiffraction focusing. Two main features of the Fano resonance are critical: (1) The Fano resonance suppresses radiation by destructive interference, thereby allowing for REI, and (2) the Fano resonance creates a resonant field enhancement allowing one to overcome evanescent decay, which is different from past approaches to REI. An analytic theory is introduced to explain these results. While the analytic theory is formulated for a perfect electric conductor, comprehensive numerical simulations show the applicability in the visible regime, where losses and plasmonic effects play a role.

Chen, Shuwen; Jin, Shilong; Gordon, Reuven

2014-07-01

398

Hormone purification by isoelectric focusing in space  

NASA Technical Reports Server (NTRS)

The objective of the program was the definition and development of optimal methods for electrophoretic separations in microgravity. The approach is based on a triad consisting of ground based experiments, mathematical modeling and experiments in microgravity. Zone electrophoresis is a rate process, where separation is achieved in uniform buffers on the basis of differences in electrophoretic mobilities. Optimization and modeling of continuous flow electrophoresis mainly concern the hydrodynamics of the flow process, including gravity dependent fluid convection due to density gradients and gravity independent electroosmosis. Optimization of focusing requires a more complex model describing the molecular transport processes involved in electrophoresis of interacting systems. Three different focusing instruments were designed, embodying novel principles of fluid stabilization. Fluid stability was achieved by: (1) flow streamlining by means of membrane elements in combination with rapid fluid recycling; (2) apparatus rotation in combination with said membrane elements; and (3) shear stress induced by rapid recycling through a narrow gap channel.

Bier, M.

1988-01-01

399

Person-focused care at Kaiser Permanente.  

PubMed

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

Bellows, Jim; Young, Scott; Chase, Alide

2014-01-01

400

Mixed waste characterization, treatment & disposal focus area  

SciTech Connect

The mission of the Mixed Waste Characterization, Treatment, and Disposal Focus Area (referred to as the Mixed Waste Focus Area or MWFA) is to provide treatment systems capable of treating DOE`s mixed waste in partnership with users, and with continual participation of stakeholders, tribal governments, and regulators. The MWFA deals with the problem of eliminating mixed waste from current and future storage in the DOE complex. Mixed waste is waste that contains both hazardous chemical components, subject to the requirements of the Resource Conservation and Recovery Act (RCRA), and radioactive components, subject to the requirements of the Atomic Energy Act. The radioactive components include transuranic (TRU) and low-level waste (LLW). TRU waste primarily comes from the reprocessing of spent fuel and the use of plutonium in the fabrication of nuclear weapons. LLW includes radioactive waste other than uranium mill tailings, TRU, and high-level waste, including spent fuel.

NONE

1996-08-01

401

Long Distance Pronominalisation and Global Focus  

Microsoft Academic Search

Our corpus of descriptive text contains a significant number of long-distance pronominal references (8.4% of the total). In order to account for how these pronouns are intepreted, we re-examine Grosz and Sidner's theory of the attentional state, and in particular the use of the global focus to supplement centering theory. Our corpus evidence concerning these long-distance pronominal references, as well

Janet Hitzeman; Massimo Poesio

1998-01-01

402

Preservation of Earth's resources focus for forum  

Microsoft Academic Search

A more efficient use of the Earth’s resources to preserve the environment for future generations was the focus of a forum held on climate change at Notre Dame’s Fremantle Campus in October.\\u000aDr Lucy Morris, Chief Executive Officer of Baptistcare; Jim Smith, Project Manager Western Australia of Catholic Earthcare Australia and Dr Michael O’Leary, Lecturer in Geography at The University

Leigh Dawson

2011-01-01

403

Borescope With Large Depth Of Focus  

NASA Technical Reports Server (NTRS)

Modification of commercial borescope yields clear, glare-free images of defects on inside of tube. Used to examine diverging wall of tube. Wall illuminated by light from fiber distinct from fused-fiber cable used for viewing. Viewing cable holds right-angle mirror at tip so it can look sideways. Image appears, magnified, on monitor. Instrument offers large depth of focus and therefore used in tubes of varying inside diameter.

Guirguis, Kamal S.

1990-01-01

404

Focus Issue: RNA, A Multifunctional Molecule  

NSDL National Science Digital Library

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

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

2005-09-06

405

Focus on high energy density physics  

NASA Astrophysics Data System (ADS)

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

Drake, R. Paul; Norreys, Peter

2014-06-01

406

Permanent magnet focused X-band photoinjector  

DOEpatents

A compact high energy photoelectron injector integrates the photocathode directly into a multicell linear accelerator with no drift space between the injection and the linac. High electron beam brightness is achieved by accelerating a tightly focused electron beam in an integrated, multi-cell, X-band rf linear accelerator (linac). The photoelectron linac employs a Plane-Wave-Transformer (PWT) design which provides strong cell-to-cell coupling, easing manufacturing tolerances and costs.

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

2002-09-10

407

Focus Issue: Regulation of Lymphocyte Function  

NSDL National Science Digital Library

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

Ernesto Andrianantoandro (American Association for the Advancement of Science; Science Signaling REV)

2012-07-31

408

STEM Focus in Innoventure Competition Theme  

SciTech Connect

This report documents the inclusion of the STEM focus in the annual competition theme for the Innoventure youth project. The STEM concepts have always played a part in the selection of the theme. However, this year, STEM is intentionally mentioned in the description of the theme to emphasize the importance of these concepts. This work is a part of the National Security Preparedness Project (NSPP), being performed under a Department of Energy (DOE)/National Nuclear Security Administration (NNSA) grant.

None

2010-03-31

409

Consumer Evaluation of Dual Focus Mutual Aid  

Microsoft Academic Search

Double Trouble in Recovery (DTR) is a “dual focus,” 12 step-based mutual aid program tailored to assist recovery from co-occurring substance use and psychiatric disorders. Objective: To determine consumers' perceptions of DTR's usefulness for their recoveries and the relationships between perceived DTR usefulness and self-help processes, self-efficacy to cope with problems in recovery, and changes in behaviors conducive to dual

Stephen Magura; Cherie L. Villano; Andrew Rosenblum; Howard S. Vogel; Thomas Betzler

2008-01-01

410

Animation of Gas Chromatography Solvent Focusing  

NSDL National Science Digital Library

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

411

Temporal focusing with spatially modulated excitation.  

PubMed

Temporal focusing of ultrashort pulses has been shown to enable wide-field depth-resolved two-photon fluorescence microscopy. In this process, an entire plane in the sample is selectively excited by introduction of geometrical dispersion to an ultrashort pulse. Many applications, such as multiphoton lithography, uncaging or region-of-interest imaging, require, however, illumination patterns which significantly differ from homogeneous excitation of an entire plane in the sample. Here we consider the effects of such spatial modulation of a temporally focused excitation pattern on both the generated excitation pattern and on its axial confinement. The transition in the axial response between line illumination and wide-field illumination is characterized both theoretically and experimentally. For 2D patterning, we show that in the case of amplitude-only modulation the axial response is generally similar to that of wide-field illumination, while for phase-and-amplitude modulation the axial response slightly deteriorates when the phase variation is rapid, a regime which is shown to be relevant to excitation by beams shaped using spatial light modulators. Finally, general guidelines for the use of spatially modulated temporally focused excitation are presented. PMID:19333304

Papagiakoumou, Eirini; de Sars, Vincent; Emiliani, Valentina; Oron, Dan

2009-03-30

412

TECHNICAL INTEGRATION ENVIRONMENTAL MANAGEMENT FOCUS AREAS  

SciTech Connect

This contract involved a team of companies led by WPI (formerly the Waste Policy Institute). In addition to WPI, the team included four subcontractors--TRW (formerly BDM Federal), SAIC, Energetics, and the University of North Dakota Energy and Environmental Research Center (EERC). The team of companies functioned as a ''seamless team'' assembled to support the Environmental Management Program Focus Areas. Staff resources were applied in the following offices: Richland, Washington, Idaho Falls, Idaho, Morgantown, West Virginia, Grand Forks, North Dakota, Aiken, South Carolina, Gaithersburg, Maryland, and Blacksburg, Virginia. These locations represented a mixture of site support offices at the field focus area locations and central staff to support across the focus areas. The management of this dispersed resource base relied on electronic communication links to allow the team to function as a ''virtual office'' to address tasks with the best qualified staff matched to the task assignments. A variety of tasks were assigned and successfully completed throughout the life of the contract that involved program planning and analysis, program execution, program information management and communication and data transmission.

Carey R. Butler

2001-10-01

413

Automatic Focus Adjustment of a Microscope  

NASA Technical Reports Server (NTRS)

AUTOFOCUS is a computer program for use in a control system that automatically adjusts the position of an instrument arm that carries a microscope equipped with an electronic camera. In the original intended application of AUTOFOCUS, the imaging microscope would be carried by an exploratory robotic vehicle on a remote planet, but AUTOFOCUS could also be adapted to similar applications on Earth. Initially control software other than AUTOFOCUS brings the microscope to a position above a target to be imaged. Then the instrument arm is moved to lower the microscope toward the target: nominally, the target is approached from a starting distance of 3 cm in 10 steps of 3 mm each. After each step, the image in the camera is subjected to a wavelet transform, which is used to evaluate the texture in the image at multiple scales to determine whether and by how much the microscope is approaching focus. A focus measure is derived from the transform and used to guide the arm to bring the microscope to the focal height. When the analysis reveals that the microscope is in focus, image data are recorded and transmitted.

Huntsberger, Terrance

2005-01-01

414

Focus Issue: Reactive Oxygen Species--Friend or Foe?  

NSDL National Science Digital Library

Science’s STKE focuses on the signaling pathways activated in response to pathological accumulation of reactive oxygen species (ROS), as well as on mechanisms by which cells have harnessed these reactive molecules as active participants in signaling that leads to a desirable cellular response. ROS are chemically reactive because they contain unpaired electrons and, depending on the location of their production and the molecules with which they interact, they can cause cellular damage or trigger specific signaling events. Indeed, kinases and phosphatases are now recognized as key molecules that can be modified by interaction with ROS, and the Protocol by Wu and Terada describes a method for detecting oxidatively modified protein tyrosine phosphatases. In a Perspective, Michel et al. discuss how susceptibility to elevated ROS contributes to death of specific neurons and in a Review, Storz discusses the signaling pathways activated to detoxify ROS and how mitochondrial ROS may contribute to aging.

Nancy R. Gough (DC; American Association for the Advancement of Science, Washington REV)

2006-04-25

415

Upgrade of the proximity focusing RICH at Jlab  

SciTech Connect

The Hall A RICH at Jefferson Lab is undergoing an upgrade to adapt to the higher momentum kinematics of the neutron spin structure Transversity experiments planned to run in 2008. The JLab RICH is a proximity focusing detector using liquid C6F14 as Cherenkov radiator, a thin layer of CsI as photon converter, evaporated on segmented pad panels of a proportional chamber. The original RICH had a superior hadron identification up to 2 GeV/c with pion/kaon rejection at the level of 1:1000 at ~ similar90% intrinsic efficiency. The upgrade will extend this performance above 2.4 GeV/c by means of a larger photon detector (a multiwire-multipad proportional chamber) and a longer proximity gap which will improve the photon detection geometrical efficiency and the angular resolution, respectively.

Cisbani, Evaristo; Colilli, Stefano; Cusanno, Francesco; Fratoni, Rolando; Frullani, Salvatore; Garibaldi, Franco; Giuliani, Fausto; Gricia, Massimo; Lucentini, Maurizio; Santavenere, Fabio; Urciuoli, Guido; Iodice, Mauro; Argentieri, A.; de Cataldo, Giacinto; De Leo, Raffaele; Lagamba, Luigi; Marrone, Stefano; Nappi, E.; Camsonne, Alexandre; Kross, Brian; Michaels, Robert; Reitz, Bodo; Segal, John; Wojtsekhowski, Bogdan; Zorn, Carl; Monno, E.; Breuer, Herbert

2009-09-01

416

Isoelectric focusing of bovine major histocompatibility complex class I molecules.  

PubMed

The products of the major histocompatibility complex (MHC) loci regulate an individual's immune response to pathogens. Cattle provide an important model to study the relationship between disease susceptibility and MHC haplotype since large half-sibling families are common. The definitive demonstration, however, of a firm relationship between MHC phenotype and disease susceptibility in cattle will require a precise definition of the bovine MHC allelic products. Available reagents for serological characterization of the bovine MHC gene products have not been adequate for these purposes. We have shown that existing mouse monoclonal antibodies and rabbit anti-human antisera precipitate bovine class I molecules, that these structures separate well by one-dimensional isoelectric focusing (1-D IEF), and that immunoprecipitation followed by 1-D IEF allows the detection of bovine class I MHC allelic products. Through this technique, we have identified previously undetected class I products. This approach will facilitate a detailed characterization of the bovine MHC class I gene products. PMID:2614073

Watkins, D I; Shadduck, J A; Stone, M E; Lewin, H A; Letvin, N L

1989-06-01

417

A Statistical Framework for Intrusion Detection in Ad Hoc Networks  

Microsoft Academic Search

We focus on detecting intrusions in ad hoc networks using the misuse detection technique. We allow for detection modules that periodically fail to detect attacks and also generate false positives. Combining theories of hypothesis testing and approximation algorithms, we develop a framework to counter different threats while minimizing the resource consumption. We obtain computationally simple optimal rules for aggregating and

Dhanant Subhadrabandhu; Saswati Sarkar; Farooq Anjum

2006-01-01

418

F.I.D.O. Focused Integration for Debris Observation  

NASA Astrophysics Data System (ADS)

The fact that satellites play a growing role in our day-to-day live, contributes to the overall assessment that these assets must be protected. As more and more objects enter space and begin to clutter this apparently endless vacuum, we begin to realize that these objects and associated debris become a potential and recurring threat. The space surveillance community routinely attempts to catalog debris through broad area search collection profiles, hoping to detect and track smaller and smaller objects. There are technical limitations to each collection system, we propose there may be new ways to increase the detection capability, effectively "Teaching an old dog (FIDO), new tricks." Far too often, we are justly criticized for never "stepping out of the box". The philosophy of "if it's not broke, don't fix it" works great if you assume that we are not broke. The assumption that in order to "Find" new space junk we need to increase our surveillance windows and try to cover as much space as possible may be appropriate for Missile Defense, but inappropriate for finding small space debris. Currently, our Phased Array Early Warning Systems support this yearly search program to try to acquire and track space small debris. A phased array can electronically scan the horizons very quickly, but the radar does have limitations. There is a closed-loop resource management equation that must be satisfied. By increasing search volume, we effectively reduce our instantaneous sensitivity which will directly impact our ability to find smaller and smaller space debris. Our proposal will be to focus on increasing sensitivity by reducing the search volume to statistically high probability of detection volumes in space. There are two phases to this proposal, a theoretical and empirical. Theoretical: The first phase will be to investigate the current space catalog and use existing ephemeris data on all satellites in the Space Surveillance Catalog to identify volumes of space with a high likelihood of encountering transiting satellite. Also during this phase, candidate radar systems will be characterized to determine sensitivity levels necessary to detect certain sized objects. Data integration plays a critical role in lowering the noise floor of the collection area in order to detect smaller and smaller objects. Reducing the search volume to these high probability of intercept areas will allow the use of data integration to increase the likelihood of detection of small Radar Cross Section objects. Empirical: The next phase is to employ this technique using a legacy collection system. The collection community may choose any collection system. The goal will be to demonstrate how focusing on a very specific area and employing data integration will increase the likelihood of detection of smaller objects. This will result in the creation of an Inter Range Vector (IRV), which can be handed-off to downrange collection systems for additional tracking. The goal of FIDO will be demonstrate how these legacy systems can be better employed to help find smaller and smaller debris.

Ploschnitznig, J.

2013-09-01

419

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

Microsoft Academic Search

This study examined anxiety development in median- (n = 74) and high-anxious children (n = 183) aged 8–13, the effect of parent- and child-focused preventive interventions on child\\/parental anxiety, and the effect of parental anxiety on child anxiety. High-anxious children were randomized into a parent-focused (n = 69), child-focused (n = 58) or non-intervention (n = 56) group. Families completed a pretest and 1- and 2-year follow-ups. Children selected as

Ellin Simon; Susan Maria Bögels; Jannie Marisol Voncken

2011-01-01

420

Acceleration of surface-based hybridization reactions using isotachophoretic focusing.  

PubMed

We present a theoretical model and experimental demonstration of a novel method for acceleration of surface-based reactions using isotachophoresis (ITP). We use ITP to focus a sample of interest and deliver a high concentration target to a prefunctionalized surface, thus enabling rapid reaction at the sensor site. The concentration of the focused analyte is bound in space by the ITP interface and, upon reaction with the surface, continues electromigrating downstream, removing any contamination or reacted sample molecules from the surface. This constitutes a one-step react-and-wash assay which can be performed in a simple channel and does not require flow control elements or moving parts. We designed a novel microfluidic chip where reaction surfaces are formed by paramagnetic beads, immobilized at desired sites by an external magnetic field. Using this chip, we compared ITP-based surface hybridization to standard continuous flow-based hybridization and experimentally demonstrated a 2 orders of magnitude improvement in limit of detection (LoD) in a 3 min nucleic acid hybridization assay. The simple analytical model we present allows prediction of the rate of surface reaction under ITP and can be used to design and optimize such assays as a function of the physical properties of the system, including buffer chemistry, applied voltage, analyte mobility, analyte concentration, probe density, and surface length. The method, model, and experimental setup can be applied to various forms or surface reactions and may serve as the basis for highly genetic analysis and immunoassays. PMID:24517175

Karsenty, Merav; Rubin, Shimon; Bercovici, Moran

2014-03-18

421

Dark Matter: Direct Detection  

SciTech Connect

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

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

2009-12-16

422

Early Detection  

Cancer.gov

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

423

Multiphoton microscopic imaging of fibrotic focus in invasive ductal carcinoma of the breast  

NASA Astrophysics Data System (ADS)

During the proliferation of breast cancer, the desmoplastic can evoke a fibrosis response by invading healthy tissue. Fibrotic focus (FF) in invasive ductal carcinoma (IDC) of the breast had been reported to be associated with significantly poorer survival rate than IDC without FF. As an important prognosis indicator, it's difficult to obtain the exact fibrotic information from traditional detection method such as mammography. Multiphoton imaging based on two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG) has been recently employed for microscopic examination of unstained tissue. In this study, multiphoton microscopy (MPM) was used to image the fibrotic focus in invasive ductal carcinoma tissue. The morphology and distribution of collagen in fibrotic focus can be demonstrated by the SHG signal. Variation of collagen between IDC with and without FF will be examined and further characterized, which may be greatly related to the metastasis of breast cancer. Our result suggested that the MPM can be efficient in identifying and locating the fibrotic focus in IDC. Combining with the pathology analysis and other detecting methods, MPM owns potential in becoming an advanced histological tool for detecting the fibrotic focus in IDC and collecting prognosis information, which may guide the subsequent surgery option and therapy procedure for patients.

Chen, Sijia; Nie, Yuting; Lian, Yuane; Wu, Yan; Fu, Fangmeng; Wang, Chuan; Zhuo, Shuangmu; Chen, Jianxin

2014-11-01

424

Plasma focus ion beam-scaling laws  

NASA Astrophysics Data System (ADS)

Measurements on plasma focus ion beams include various advanced techniques producing a variety of data which has yet to produce benchmark numbers. Recent numerical experiments using an extended version of the Lee Code has produced reference numbers and scaling trends for number and energy fluence of deuteron beams as functions of stored energy E0. At the pinch exit the ion number fluence (ions m-2) and energy fluence (J m-2) computed as 2.4-7.8×1020 and 2.2-33×106 respectively were found to be independent of E0 from 0.4 - 486 kJ. This work was extended to the ion beams for various gases. The results show that, for a given plasma focus, the fluence, flux, ion number and ion current decrease from the lightest to the heaviest gas except for trend-breaking higher values for Ar fluence and flux. The energy fluence, energy flux, power flow and damage factors are relatively constant from H2 to N2 but increase for Ne, Ar, Kr and Xe due to radiative cooling and collapse effects. This paper reviews this work and in a concluding section attempts to put the accumulating large amounts of data into the form of a scaling law of beam energy Ebeam versus storage energy E0 taking the form for deuteron as: {Ebeam} = 18.2{E}01.23; where Ebeam is in J and E0 is in kJ. It is hoped that the establishment of such scaling laws places on a firm footing the reference quantitative ideas for plasma focus ion beams.

Saw, S. H.

2014-08-01

425

Detection Technology  

Cancer.gov

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

426

Plasma focus based repetitive source of fusion neutrons and hard x-rays  

Microsoft Academic Search

A plasma focus device capable of operating at 0.2 pulses per second during several minutes is used as a source of hard x-rays and fast neutrons. An experimental demonstration of the use of the neutrons emissions for radiation probing of hydrogenated substances is presented, showing a particular application in detecting water concentrations differences in the proximity of the device by

V. Raspa; F Di Lorenzo; P. Knoblauch; A. Lazarte; A. Tartaglione; A. Clausse; C. Moreno

2008-01-01

427

Impact of the wave number estimation in Underground Focusing SAR images  

Microsoft Academic Search

This work studies the impact estimating soil wave number in Underground Focusing SAR imaging for tunnel detection applications. It is demonstrated that poor underground imaging results when wave refraction at the ground surface is neglected, but that incorporating refraction with sufficiently high estimates of soil dielectric constant produce clear target images. Using a wrong wave number for the soil incorrectly

Fernando Quivira; Jose Angel Martinez Lorenzo; Carey M. Rappaport

2010-01-01

428

Nanoscintillators for radiation detection  

NASA Astrophysics Data System (ADS)

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

Hall, Ryan Gregory

429

Perfectly monodisperse microbubbling by capillary flow focusing.  

PubMed

Here we report a simple microfluidics phenomenon which allows the efficient mass production of micron size gas bubbles with a perfectly monodisperse and controllable diameter. It resorts on a self-excited breakup phenomenon (which locks at a certain frequency) of a short gas microligament coflowing in a focused liquid stream. In this work, we describe the physics of the phenomenon and obtain closed expressions for the bubble diameter as a function of the liquid and gas properties, geometry, and flow parameters, from a large set of experimental results. PMID:11800883

Gañán-Calvo, A M; Gordillo, J M

2001-12-31

430

Analytical modeling of line focus solar collectors  

SciTech Connect

Solar thermal electric power generation systems and industrial process heat systems generating steam through flash vaporization require a constant outlet temperature from the collector field. This constant temperature is most efficiently maintained by adjusting the circulating fluid flow rate. Successful design of analog controllers for this regulation requires knowledge of system dynamics and the nonlinear nature of the system parameters. Simplified models relating deviations in outlet temperature to changes in inlet temperature, insolation, and fluid flow rate illustrate the basic responses and the distributed-parameter nature of line focus collectors. Detailed models are used to develop transfer functions and frequency response curves useful for design.

Wright, J.D.

1980-04-01

431

Focus point from direct gauge mediation  

NASA Astrophysics Data System (ADS)

This paperis devoted to the reconciliation of the tension between the theoretic expectation from naturalness and the present LHC limits on the superpartner mass bounds. We argue that in supersymmetry models of direct gauge mediation the focusing phenomenon appears, which dramatically reduces the fine tuning associated to the 126 GeV Higgs boson. This type of model is highly predictive as regards the mass spectrum, with a multi-TeV third generation, the term of order 1 TeV, gluino mass above LHC mass bound, and the light neutralinos and charginos below 1 TeV.

Zheng, Sibo

2015-01-01

432

Focus Issue: Systems Analysis of Protein Phosphorylation  

NSDL National Science Digital Library

Kinases and phosphatases are key regulatory molecules that participate in most cell signaling pathways. Systems-level analyses are providing new insights into phosphorylation sites and kinase specificity, and phosphoproteomic analyses are creating not just a wealth of data, but are also revealing rich revelations about cellular behavior, cellular responses to changing environmental conditions, and mechanisms of disease. Phosphatases are not merely signal terminators, but play active roles in signal transduction and are especially important in redox signaling. In this Focus Issue, Science Signaling highlights protein phosphorylation as the center of the signaling universe.

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

2010-08-31

433

Deep focus earthquakes in the laboratory  

NASA Astrophysics Data System (ADS)

While the existence of deep earthquakes have been known since the 1920's, the essential mechanical process responsible for them is still poorly understood and remained one of the outstanding unsolved problems of geophysics and rock mechanics. Indeed, deep focus earthquake occur in an environment fundamentally different from that of shallow (<100 km) earthquakes. As pressure and temperature increase with depth however, intra-crystalline plasticity starts to dominate the deformation regime so that rocks yield by plastic flow rather than by brittle fracturing. Olivine phase transitions have provided an attractive alternative mechanism for deep focus earthquakes. Indeed, the Earth mantle transition zone (410-700km) is the locus of the two successive polymorphic transitions of olivine. Such scenario, however, runs into the conceptual barrier of initiating failure in a pressure (P) and temperature (T) regime where deviatoric stress relaxation is expected to be achieved through plastic flow. Here, we performed laboratory deformation experiments on Germanium olivine (Mg2GeO4) under differential stress at high pressure (P=2-5GPa) and within a narrow temperature range (T=1000-1250K). We find that fractures nucleate at the onset of the olivine to spinel transition. These fractures propagate dynamically (i.e. at a non-negligible fraction of the shear wave velocity) so that intense acoustic emissions are generated. Similar to deep-focus earthquakes, these acoustic emissions arise from pure shear sources, and obey the Gutenberg-Richter law without following Omori's law. Microstructural observations prove that dynamic weakening likely involves superplasticity of the nanocrystalline spinel reaction product at seismic strain rates. Although in our experiments the absolute stress value remains high compared to stresses expected within the cold core of subducted slabs, the observed stress drops are broadly consistent with those calculated for deep earthquakes. Constant differential stress conditions at failure over a wide range of confinement (2-5GPa) strongly suggest that transformational faulting is largely independent of normal stress and thus involves non-frictional processes. We suggest that rupture nucleation is controlled by dislocation density and spinel nucleation kinetics, while propagation is controlled by superplastic flow. High stress and high dislocation density conditions can be met in a cold subducting slab full of metastable olivine, due to stress concentrations at the micro and mesoscopic scales because of buckling, folding, and/or inherited fractures. This is particularly true in the Tonga-Kermadec region for instance, for which the largest catalog of deep focus earthquake is available.

Schubnel, Alexandre; Brunet, Fabrice; Hilairet, Nadège; Gasc, Julien; Wang, Yanbin; Green, Harry W., II

2014-05-01

434

Focus Issue: Understanding Mechanisms of Inflammation  

NSDL National Science Digital Library

This Focus Issue of Science Signaling, which complements the Science Special Issue on Inflammation, includes research that reveals regulators of a receptor implicated in an inflammatory bowel disease, as well as the contribution of a matrix metalloproteinase to skin inflammation. Perspectives discuss the role of proinflammatory cytokines in brain inflammatory disorders and the regulation of multiple types of cell death in tissues in response to proinflammatory factors. Together with content from the Science Signaling Archives, these articles underline the importance of understanding the basis of inflammatory responses that can both protect and harm the host.

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

2013-01-15

435

Polarization singularities of focused, radially polarized fields  

NASA Astrophysics Data System (ADS)

The state of polarization of strongly focused, radially polarized electromagnetic fields is examined. It is found that several types of polarization singularities exist. Their relationship is investigated, and it is demonstrated that on smoothly varying a system parameter, such as the aperture angle of the lens, different polarization singularities can annihilate each other. For example, the evolution of a lemon into a monstar and its subsequent annihilation with a star is studied. Also, the quite rare collision of a C-line and an L -line, resulting in a V-point, is observed.

Schoonover, R. W.; Visser, T. D.

2006-06-01

436

Cascaded Free-flow Isoelectric Focusing for Improved Focusing Speed and Resolution  

PubMed Central

This work presents the first implementation of cascaded stages for a microfabricated free-flow isoelectric focusing device. Both analytical and computational models for IEF suggest device performance will be improved by utilizing multiple stages to reduce device residence time. These models are shown to be applicable by using focusing of small IEF markers as a demonstration. We also show focusing of fluorescently tagged proteins under different channel geometries, with the most efficient focusing occurring in the cascaded design, as predicted by theory. An additional aim of this work is to demonstrate the compatibility of cascaded FF-IEF with common bioanalytical tools. As an example, outlet fractions from cascaded FF-IEF were analyzed by SDS-PAGE. Processing of whole cell lysate followed by immunoblotting for cell signaling markers demonstrates the reduction of albumin from samples, as well as the enrichment of apoptotic markers. PMID:17994708

Albrecht, Jacob W.; El-Ali, Jamil; Jensen, Klavs F.

2008-01-01

437

Nanomechanics of biomolecules: focus on DNA  

Microsoft Academic Search

Nano-mechanical measurements and manipulations at the single-cell and single-molecular levels using the atomic force microscope\\u000a (AFM) and optical tweezers are presenting fascinating opportunities to the researchers in bioscience and biotechnology. Single\\u000a molecule biophysics technologies, due to their capability to detect transient states of molecules and biomolecular complexes,\\u000a are the methods of choice for studies in DNA structure and dynamics, DNA-DNA

Y. Eugene Pak; Dae Shick Kim; Mohana Marimuthu; Sanghyo Kim

2009-01-01

438

Performance in attentional tasks following meditative focusing and focusing without meditation  

PubMed Central

Background/Aims: Ancient Indian yoga texts have described four mental states. These are caïcalatä (random thinking), ek?grat? (focusing without meditation), dh?ra?? (meditative focusing), and dhy?na (defocused meditative expansiveness). A previous study compared the performance in a cancellation task at the beginning and end of each of the four mental states (practiced for 20 minutes each, on four separate days) showed an increase in the scores after dh?ra?? Hence, the present study was designed to assess the effects of dh?ra?? (meditative focusing) and ek?grat? (focusing without meditation) on two attention tasks (i) d2 test of attention and (ii) digit symbol substitution test. Materials and Methods: Sixty normal healthy male volunteers with ages ranging from 17 to 38 years (group mean age ± S.D., 24.87 ± 4.95) were studied. Assessments were made before and after the practice of ek?grat? and dh?ra?? on two separate days. Results: After both types of focusing, there was a significant improvement in all measures of the d2 test of attention (TN, E, TN-E, E%, and CP). However, the performance in the digit symbol substitution test was better after dh?ra?? but did not change after ek?grat?. Conclusions: Hence, in summary, dh?ra?? (meditative focusing) and ek?grat? (focusing without meditation) produce nearly comparable results though dh?ra?? (meditative focusing) results in better incidental learning and better accuracy (as assessed by the substitution task). PMID:23929995

Raghavendra, B. R.; Telles, Shirley

2012-01-01

439

Nongynecologic findings on pelvic ultrasound: focus on gastrointestinal diseases.  

PubMed

Ultrasound (US) is considered the first-line imaging modality of choice in women presenting with pelvic complaints. Although imaging is focused on detecting abnormalities of the uterus and adnexa, occasionally nongynecologic findings are detected, which may or may not explain the patient's symptoms. Many of these findings are related to the gastrointestinal (GI) tract. Although most of these GI abnormalities are better diagnosed with computed tomography (CT), symptoms are often nonspecific and US may be the first imaging modality requested by referring clinicians. Sonographers should be aware of the possibility of nongynecologic diseases in patients with pelvic symptoms, particularly if US evaluation of the female reproductive tract does not provide an answer to the clinical question. Careful attention to the bowel when performing a pelvic US may allow the sonographer to diagnose GI pelvic diseases such as appendicitis, diverticulitis, colitis, bowel obstruction, mesenteric adenitis, epiploic appendagitis, Crohn disease, and even GI malignancy. As concerns grow regarding the radiation dose of pelvic CT, the use of iodinated contrast material, and imaging costs, US examination may be increasingly requested as an initial imaging study in patients in whom GI diseases is primarily suspected in the pelvis, and familiarity with the various sonographic manifestations will aid considerably in establishing the correct diagnosis. PMID:22634768

Baltarowich, Oksana H; Scoutt, Leslie M; Hamper, Ulrike M

2012-06-01

440

Development, Testing, and Findings of a Pediatric Focused Trigger Tool to Identify Medication-Related Harm in US Children's Hospitals  

Microsoft Academic Search

OBJECTIVES. The purposes of this study were to develop a pediatric-focused tool for adverse drug event detection and describe the incidence and characteristics of ad- verse drug events in children's hospitals identified by this tool. METHODS. A pediatric-specific trigger tool for adverse drug event detection was devel- oped and tested. Eighty patients from each site were randomly selected for retro-

Glenn S. Takata; Wilbert Mason; Carol Taketomo; Tina Logsdon; Paul J. Sharek

2009-01-01

441

Nature Detectives  

ERIC Educational Resources Information Center

Richard Louv's "Last Child in the Woods" (2008) added to a growing consensus to get children outside and experiencing nature. Using ideas from place-based education, the authors present a simple year-long project that brings science, nature, and other curriculum standards to life right in your school yard. With a focus on journaling, this project…

Harr, Natalie; Lee, Richard E.; Jr.

2010-01-01

442

Development of a Tissue-Mimicking Phantom for Evaluating the Focusing Performance of High Intensity Focused Ultrasound  

SciTech Connect

Objectives: To develop a tissue mimicking phantom which can be used to evaluate the focusing performance of the HIFU transducer, and the phantom should has the same acoustic characteristic and thermotics characteristic as the biological tissue. Materials and methods: The tissue mimicking phantom was made from water, gelatin, fresh biologic tissue Its ultrasonic parameters (attenuation coefficient) of the phantom was measured by the method of radiation pressure, and thermotics parameters of the phantom, including thermal conductivity, specific heat/fusion point et al were tested under the Measurement meter. The HIFU biological effect of the phantom was evaluated under the Model JC focused ultrasound tumor therapeutic system, developed and produced by Chongqing HIFU Technology Co. Ltd (working frequency: 0.7MHz; acoustic power: 200W; focal distance: 135mm; Acoustic focal region: 3x3x25 cubic mm). Results: The self-made phantom is sable, has smooth and glossy appearance, well-distributed construction, and good elasticity. We measured the followed values for acoustic and thermal properties: density 1049{+-}2 kg/m3; attenuation 0.532{+-}0.017 dB/cm (0.8 MHz), 0.612{+-}0.021 dB/cm (1.0 MHz); thermal conductivity 0.76{+-}0.08 W/m/- deg. C; specific heat 3653{+-}143 J/kg- deg. C; fusion point154{+-}8 deg. C. The BFR induced in the phantom after HIFU exposure was stable in its size and appearance. Conclusion: We produced and improved one tissue mimicking phantom successfully which had semblable ultrasound and thermphysical properties like the soft tissue, and can replace the bovine liver to investigate the HIFU biological effect and to detect the focusing performance of the HIFU energy transducer. The research was supported by Chongqing University of Medical Science (CX200320)

Jing Zongyu; Li Faqi; Zou Jiangzhong; Wang Zhibiao [Institute of Ultrasound Engineering in Medicine, Biomedical Engineering Dept., Chongqing University of Medical Sciences, Chongqing 400016 (China)

2006-05-08

443

[Pseudo color method for the infrared thermogram display of local breast focus tissue].  

PubMed

An infrared thermogram which reflects the human body surface temperature distribution can be obtained through detecting the infrared thermal radiation from each point on the human body surface. When a malignant tumor occurs in a breast, it will cause an increase in the prominent temperature in the breast surface focus region due to the abnormal blood transmission state of local focus tissue. Breast cancer can be detected through the visual analysis of the focus regions by physicians. In order to help physicians better find these focus regions, the present paper improved the traditional pseudo color display method by introducing visual effect factor and made the focus regions have a better display effect. The efficacy of this method was verified in the breast infrared thermograms of 47 breast cancer patients. The result from visual analysis of the focus region in infrared thermogram by this method can also be compared with the tissue blood transmission state from near infrared spectroscopy (NIRS) and other methods. It will be helpful to obtain more accurate diagnostic information. PMID:19455784

Tang, Xian-Wu; Ding, Hai-Shu; Teng, Yi-Chao

2009-03-01

444

Art exhibit focuses on African astronomy  

NASA Astrophysics Data System (ADS)

Connections between Africans and astronomy are the focus of a new exhibition in the National Museum of African Art in Washington, D. C. “African Cosmos: Stellar Arts,” which includes artwork, cultural items, and scientific displays from ancient to contemporary times, is the first major exhibit “that brings together arts and science focused on Africa's contribution to keen observations of the heavens over time,” curator Christine Mullen Kreamer said at a 20 June news briefing. Among the exhibit's nearly 100 objects are an ancient Egyptian mummy board that includes a representation of the sky goddess Nut, sculptures by the Dogon people of Mali depicting figures in relation to the cosmos, a video that uses data from two square degrees of the Hubble Space Telescope Cosmic Evolution Survey, and a nearly floor-to-ceiling “Rainbow Serpent” constructed of plastic containers by Benin artist Hazoume. An untitled acrylic painting (Figure 1) by South African Gavin Jantjes evokes a myth of the Khoi San people of southern Africa, as it portrays a girl throwing evening fire embers into the night sky, where they remained as the Milky Way.

Showstack, Randy

2012-07-01

445

MRI guidance for focused ultrasound surgery  

NASA Astrophysics Data System (ADS)

Magnetic resonance imaging (MRI) based monitoring has been shown in recent years to enhance the effectiveness of minimally or noninvasive thermal therapy techniques, such as focused ultrasound surgery. MR imaging's unique soft tissue contrast and ability to image in three dimensions and in any orientation make it extremely useful for treatment planning and for imaging the tissue response to the therapy. The temperature sensitivity of several intrinsic parameters enables MRI to visualize and quantify the progress an ongoing thermal treatment. The most useful temperature-sensitive parameter appears to be the proton resonant frequency, which allows for precise and accurate temperature measurements in water-based tissues. By acquiring a time series of quantitative temperature images, it is possible to monitor the accumulated thermal dose delivered to the target tissue and accurately predict the areas that are thermally ablated, while at the same time ensuring nearby critical structures are not heated. The method is currently used in an FDA approved focused ultrasound device for the treatment of uterine fibroids. Our research and clinical experience with these techniques will be reviewed.

McDannold, Nathan; Hynynen, Kullervo

2005-09-01

446

Scanning focused refractive-index microscopy.  

PubMed

We present a novel scanning focused refractive-index microscopy (SFRIM) technique to obtain the refractive index (RI) profiles of objects. The method uses a focused laser as the light source, and combines the derivative total reflection method (DTRM), projection magnification, and scanning technique together. SFRIM is able to determine RIs with an accuracy of 0.002, and the central spatial resolution achieved is 1 µm, which is smaller than the size of the focal spot. The results of measurements carried out on cedar oil and a gradient-refractive-index (GRIN) lens agree well with theoretical expectations, verifying the accuracy of SFRIM. Furthermore, using SFRIM, to the best of our knowledge we have extracted for the first time the RI profile of a periodically modulated photosensitive gelatin sample. SFRIM is the first RI profile-resolved reflected light microscopy technique that can be applied to scattering and absorbing samples. SFRIM enables the possibility of performing RI profile measurements in a variety of applications, including optical waveguides, photosensitive materials and devices, photorefractive effect studies, and RI imaging in biomedical fields. PMID:25008374

Sun, Teng-Qian; Ye, Qing; Wang, Xiao-Wan; Wang, Jin; Deng, Zhi-Chao; Mei, Jian-Chun; Zhou, Wen-Yuan; Zhang, Chun-Ping; Tian, Jian-Guo

2014-01-01

447

Scanning focused refractive-index microscopy  

NASA Astrophysics Data System (ADS)

We present a novel scanning focused refractive-index microscopy (SFRIM) technique to obtain the refractive index (RI) profiles of objects. The method uses a focused laser as the light source, and combines the derivative total reflection method (DTRM), projection magnification, and scanning technique together. SFRIM is able to determine RIs with an accuracy of 0.002, and the central spatial resolution achieved is 1 µm, which is smaller than the size of the focal spot. The results of measurements carried out on cedar oil and a gradient-refractive-index (GRIN) lens agree well with theoretical expectations, verifying the accuracy of SFRIM. Furthermore, using SFRIM, to the best of our knowledge we have extracted for the first time the RI profile of a periodically modulated photosensitive gelatin sample. SFRIM is the first RI profile-resolved reflected light microscopy technique that can be applied to scattering and absorbing samples. SFRIM enables the possibility of performing RI profile measurements in a variety of applications, including optical waveguides, photosensitive materials and devices, photorefractive effect studies, and RI imaging in biomedical fields.

Sun, Teng-Qian; Ye, Qing; Wang, Xiao-Wan; Wang, Jin; Deng, Zhi-Chao; Mei, Jian-Chun; Zhou, Wen-Yuan; Zhang, Chun-Ping; Tian, Jian-Guo

2014-07-01

448

Planar Holographic Metasurfaces for Terahertz Focusing  

NASA Astrophysics Data System (ADS)

Scientists and laymen alike have always been fascinated by the ability of lenses and mirrors to control light. Now, with the advent of metamaterials and their two-dimensional counterpart metasurfaces, such components can be miniaturized and designed with additional functionalities, holding promise for system integration. To demonstrate this potential, here ultrathin reflection metasurfaces (also called metamirrors) designed for focusing terahertz radiation into a single spot and four spaced spots are proposed and experimentally investigated at the frequency of 0.35 THz. Each metasurface is designed using a computer-generated spatial distribution of the reflection phase. The phase variation within 360 deg is achieved via a topological morphing of the metasurface pattern from metallic patches to U-shaped and split-ring resonator elements, whose spectral response is derived from full-wave electromagnetic simulations. The proposed approach demonstrates a high-performance solution for creating low-cost and lightweight beam-shaping and beam-focusing devices for the terahertz band.

Kuznetsov, Sergei A.; Astafev, Mikhail A.; Beruete, Miguel; Navarro-Cía, Miguel

2015-01-01

449

Focus of attention and automaticity in handwriting.  

PubMed

This study investigated the nature of automaticity in everyday tasks by testing handwriting performance under single and dual-task conditions. Item familiarity and hand dominance were also manipulated to understand both cognitive and motor components of the task. In line with previous literature, performance was superior in an extraneous focus of attention condition compared to two different skill focus conditions. This effect was found only when writing with the dominant hand. In addition, performance was superior for high familiarity compared to low familiarity items. These findings indicate that motor and cognitive familiarity are related to the degree of automaticity of motor skills and can be manipulated to produce different performance outcomes. The findings also imply that the progression of skill acquisition from novel to novice to expert levels can be traced using different dual-task conditions. The separation of motor and cognitive familiarity is a new approach in the handwriting domain, and provides insight into the nature of attentional demands during performance. PMID:24423388

MacMahon, Clare; Charness, Neil

2014-04-01

450

Scanning focused refractive-index microscopy  

PubMed Central

We present a novel scanning focused refractive-index microscopy (SFRIM) technique to obtain the refractive index (RI) profiles of objects. The method uses a focused laser as the light source, and combines the derivative total reflection method (DTRM), projection magnification, and scanning technique together. SFRIM is able to determine RIs with an accuracy of 0.002, and the central spatial resolution achieved is 1?µm, which is smaller than the size of the focal spot. The results of measurements carried out on cedar oil and a gradient-refractive-index (GRIN) lens agree well with theoretical expectations, verifying the accuracy of SFRIM. Furthermore, using SFRIM, to the best of our knowledge we have extracted for the first time the RI profile of a periodically modulated photosensitive gelatin sample. SFRIM is the first RI profile-resolved reflected light microscopy technique that can be applied to scattering and absorbing samples. SFRIM enables the possibility of performing RI profile measurements in a variety of applications, including optical waveguides, photosensitive materials and devices, photorefractive effect studies, and RI imaging in biomedical fields. PMID:25008374

Sun, Teng-Qian; Ye, Qing; Wang, Xiao-Wan; Wang, Jin; Deng, Zhi-Chao; Mei, Jian-Chun; Zhou, Wen-Yuan; Zhang, Chun-Ping; Tian, Jian-Guo

2014-01-01

451

Planar holographic metasurfaces for terahertz focusing.  

PubMed

Scientists and laymen alike have always been fascinated by the ability of lenses and mirrors to control light. Now, with the advent of metamaterials and their two-dimensional counterpart metasurfaces, such components can be miniaturized and designed with additional functionalities, holding promise for system integration. To demonstrate this potential, here ultrathin reflection metasurfaces (also called metamirrors) designed for focusing terahertz radiation into a single spot and four spaced spots are proposed and experimentally investigated at the frequency of 0.35 THz. Each metasurface is designed using a computer-generated spatial distribution of the reflection phase. The phase variation within 360 deg is achieved via a topological morphing of the metasurface pattern from metallic patches to U-shaped and split-ring resonator elements, whose spectral response is derived from full-wave electromagnetic simulations. The proposed approach demonstrates a high-performance solution for creating low-cost and lightweight beam-shaping and beam-focusing devices for the terahertz band. PMID:25583565

Kuznetsov, Sergei A; Astafev, Mikhail A; Beruete, Miguel; Navarro-Cía, Miguel

2015-01-01

452

SIAM Workshop: Focus on Diversity 2001  

SciTech Connect

The Society for Industrial and Applied Mathematics (SIAM) held a workshop focused on underrepresented minorities--graduate and undergraduate students, postdocs, and recent Ph.D's--in the mathematical and computational sciences on July 11, 2001, as part of the SIAM Annual Meeting in San Diego, California. The workshop was intended to accomplish several goals: (1) to a provide workshop focused on careers for and retention of minority students in the mathematical and computational sciences; (2) to bring together a mixture of people from different levels of professional experience, ranging from undergraduate students to senior scientists in an informal setting in order to share career experiences and options; (3) to provide an opportunity for minority graduate students, postdocs, and recent Ph.D's to present their research at an international meeting; (4) to expose undergraduate students to the many professional opportunities resulting from graduate degrees in science and mathematics; and (5) to encourage undergraduate and graduate students to speak frankly with each other about personal issues and experiences associated with pursuing a scientific career.

None

2001-01-01