An Angular Method with Position Control for Block Mesh Squareness Improvement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, J.; Stillman, D.

We optimize a target function de ned by angular properties with a position control term for a basic stencil with a block-structured mesh, to improve element squareness in 2D and 3D. Comparison with the condition number method shows that besides a similar mesh quality regarding orthogonality can be achieved as the former does, the new method converges faster and provides a more uniform global mesh spacing in our numerical tests.

A Study of a Mini-Drift GEM Tracking Detector

NASA Astrophysics Data System (ADS)

Azmoun, B.; DiRuzza, B.; Franz, A.; Kiselev, A.; Pak, R.; Phipps, M.; Purschke, M. L.; Woody, C.

2016-06-01

A GEM tracking detector with an extended drift region has been studied as part of an effort to develop new tracking detectors for future experiments at RHIC and for the Electron Ion Collider that is being planned for BNL or JLAB. The detector consists of a triple GEM stack with a 1.6 cm drift region that was operated in a mini TPC type configuration. Both the position and arrival time of the charge deposited in the drift region were measured on the readout plane which allowed the reconstruction of a short vector for the track traversing the chamber. The resulting position and angle information from the vector could then be used to improve the position resolution of the detector for larger angle tracks, which deteriorates rapidly with increasing angle for conventional GEM tracking detectors using only charge centroid information. Two types of readout planes were studied. One was a COMPASS style readout plane with 400 μm pitch XY strips and the other consisted of 2 × 10 mm2 chevron pads. The detector was studied in test beams at Fermilab and CERN, along with additional measurements in the lab, in order to determine its position and angular resolution for incident track angles up to 45 degrees. Several algorithms were studied for reconstructing the vector using the position and timing information in order to optimize the position and angular resolution of the detector for the different readout planes. Applications for large angle tracking detectors at RHIC and EIC are also discussed.

Position Sensitive Proximity Charge Sensing Readout of HPGe Detectors

NASA Astrophysics Data System (ADS)

Priest, Anders Peterson

Electrode segmentation is a necessity to achieve position sensitivity in semicon- ductor radiation detectors. Traditional segmentation requires decreasing electrode sizes while increasing channel numbers to achieve very fine position resolution. These electrodes can be complicated to fabricate, and many electrodes with individual electronic channels are required to instrument large detector areas. To simplify the fabrication process, we have moved the readout electrodes onto a printed circuit board that is positioned above the ionization type detection material. In this scheme, charge from radiation interactions will be shared amongst several electrodes, allowing for position interpolation. Because events can be reconstructed in between electrodes, fewer electrodes are needed to instrument large detector areas. The proximity charge sensing method of readout promises to simplify detector fabrication while maintaining the position resolution that is required by fields such as homeland security, astrophysics, environmental remediation, nuclear physics, and medical imaging. We performed scanning measurements on a proof of principle detector that we fabricated at Lawrence Berkeley National Laboratory (LBNL). These measurements showed that position resolution much finer than the strip pitch was achievable using the proximity charge readout method. We performed analytic calculations and Monte Carlo modeling to optimize the readout electrode geometry for a larger detector to test the limits of this technology. We achieved an average position resolution of 288 microm with eight proximity electrodes at a 5 mm pitch and 1 mm strip width, set 100 microm away from the detector surface by a Kapton spacer. To achieve this resolution using standard technologies, 300 microm pitch strips are necessary, and would require 100 channels to instrument the same area. Through our optimization calculations, we found that there is a trade-off between position resolution and energy resolution, and this system provided comparatively poor energy resolution by HPGe standards, with 4.7 keV FWHM at 59.5 keV. With another electrode geometry, we were able to achieve 2.9 keV FWHM at 59.5 keV. This dissertation describes the work we completed to achieve these results.

Time and position sensitive single photon detector for scintillator read-out

NASA Astrophysics Data System (ADS)

Schössler, S.; Bromberger, B.; Brandis, M.; Schmidt, L. Ph H.; Tittelmeier, K.; Czasch, A.; Dangendorf, V.; Jagutzki, O.

2012-02-01

We have developed a photon counting detector system for combined neutron and γ radiography which can determine position, time and intensity of a secondary photon flash created by a high-energy particle or photon within a scintillator screen. The system is based on a micro-channel plate photomultiplier concept utilizing image charge coupling to a position- and time-sensitive read-out anode placed outside the vacuum tube in air, aided by a standard photomultiplier and very fast pulse-height analyzing electronics. Due to the low dead time of all system components it can cope with the high throughput demands of a proposed combined fast neutron and dual discrete energy γ radiography method (FNDDER). We show tests with different types of delay-line read-out anodes and present a novel pulse-height-to-time converter circuit with its potential to discriminate γ energies for the projected FNDDER devices for an automated cargo container inspection system (ACCIS).

A Study of a Mini-Drift GEM Tracking Detector

DOE PAGES

Azmoun, B.; DiRuzza, B.; Franz, A.; ...

2016-06-22

In this paper, a GEM tracking detector with an extended drift region has been studied as part of an effort to develop new tracking detectors for future experiments at RHIC and for the Electron Ion Collider that is being planned for BNL or JLAB. The detector consists of a triple GEM stack with a 1.6 cm drift region that was operated in a mini TPC type configuration. Both the position and arrival time of the charge deposited in the drift region were measured on the readout plane which allowed the reconstruction of a short vector for the track traversing themore » chamber. The resulting position and angle information from the vector could then be used to improve the position resolution of the detector for larger angle tracks, which deteriorates rapidly with increasing angle for conventional GEM tracking detectors using only charge centroid information. Two types of readout planes were studied. One was a COMPASS style readout plane with 400 μm pitch XY strips and the other consisted of 2 × 10 mm 2 chevron pads. The detector was studied in test beams at Fermilab and CERN, along with additional measurements in the lab, in order to determine its position and angular resolution for incident track angles up to 45 degrees. Several algorithms were studied for reconstructing the vector using the position and timing information in order to optimize the position and angular resolution of the detector for the different readout planes. Finally, applications for large angle tracking detectors at RHIC and EIC are also discussed.« less

A Study of a Mini-Drift GEM Tracking Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azmoun, B.; DiRuzza, B.; Franz, A.

In this paper, a GEM tracking detector with an extended drift region has been studied as part of an effort to develop new tracking detectors for future experiments at RHIC and for the Electron Ion Collider that is being planned for BNL or JLAB. The detector consists of a triple GEM stack with a 1.6 cm drift region that was operated in a mini TPC type configuration. Both the position and arrival time of the charge deposited in the drift region were measured on the readout plane which allowed the reconstruction of a short vector for the track traversing themore » chamber. The resulting position and angle information from the vector could then be used to improve the position resolution of the detector for larger angle tracks, which deteriorates rapidly with increasing angle for conventional GEM tracking detectors using only charge centroid information. Two types of readout planes were studied. One was a COMPASS style readout plane with 400 μm pitch XY strips and the other consisted of 2 × 10 mm 2 chevron pads. The detector was studied in test beams at Fermilab and CERN, along with additional measurements in the lab, in order to determine its position and angular resolution for incident track angles up to 45 degrees. Several algorithms were studied for reconstructing the vector using the position and timing information in order to optimize the position and angular resolution of the detector for the different readout planes. Finally, applications for large angle tracking detectors at RHIC and EIC are also discussed.« less

Non-woven PGA/PVA fibrous mesh as an appropriate scaffold for chondrocyte proliferation.

PubMed

Rampichová, M; Koštáková, E; Filová, E; Prosecká, E; Plencner, M; Ocheretná, L; Lytvynets, A; Lukáš, D; Amler, E

2010-01-01

Non-woven textile mesh from polyglycolic acid (PGA) was found as a proper material for chondrocyte adhesion but worse for their proliferation. Neither hyaluronic acid nor chitosan nor polyvinyl alcohol (PVA) increased chondrocyte adhesion. However, chondrocyte proliferation suffered from acidic byproducts of PGA degradation. However, the addition of PVA and/or chitosan into a wet-laid non-woven textile mesh from PGA improved chondrocyte proliferation seeded in vitro on the PGA-based composite scaffold namely due to a diminished acidification of their microenvironment. This PVA/PGA composite mesh used in combination with a proper hydrogel minimized the negative effect of PGA degradation without dropping positive parameters of the PGA wet-laid non-woven textile mesh. In fact, presence of PVA and/or chitosan in the PGA-based wet-laid non-woven textile mesh even advanced the PGA-based wet-laid non-woven textile mesh for chondrocyte seeding and artificial cartilage production due to a positive effect of PVA in such a scaffold on chondrocyte proliferation.

The Role of Chronic Mesh Infection in Delayed-Onset Vaginal Mesh Complications or Recurrent Urinary Tract Infections: Results From Explanted Mesh Cultures.

PubMed

Mellano, Erin M; Nakamura, Leah Y; Choi, Judy M; Kang, Diana C; Grisales, Tamara; Raz, Shlomo; Rodriguez, Larissa V

2016-01-01

Vaginal mesh complications necessitating excision are increasingly prevalent. We aim to study whether subclinical chronically infected mesh contributes to the development of delayed-onset mesh complications or recurrent urinary tract infections (UTIs). Women undergoing mesh removal from August 2013 through May 2014 were identified by surgical code for vaginal mesh removal. Only women undergoing removal of anti-incontinence mesh were included. Exclusion criteria included any women undergoing simultaneous prolapse mesh removal. We abstracted preoperative and postoperative information from the medical record and compared mesh culture results from patients with and without mesh extrusion, de novo recurrent UTIs, and delayed-onset pain. One hundred seven women with only anti-incontinence mesh removed were included in the analysis. Onset of complications after mesh placement was within the first 6 months in 70 (65%) of 107 and delayed (≥6 months) in 37 (35%) of 107. A positive culture from the explanted mesh was obtained from 82 (77%) of 107 patients, and 40 (37%) of 107 were positive with potential pathogens. There were no significant differences in culture results when comparing patients with delayed-onset versus immediate pain, extrusion with no extrusion, and de novo recurrent UTIs with no infections. In this large cohort of patients with mesh removed for a diverse array of complications, cultures of the explanted vaginal mesh demonstrate frequent low-density bacterial colonization. We found no differences in culture results from women with delayed-onset pain versus acute pain, vaginal mesh extrusions versus no extrusions, or recurrent UTIs using standard culture methods. Chronic prosthetic infections in other areas of medicine are associated with bacterial biofilms, which are resistant to typical culture techniques. Further studies using culture-independent methods are needed to investigate the potential role of chronic bacterial infections in delayed vaginal mesh complications.

Segmented AC-coupled readout from continuous collection electrodes in semiconductor sensors

DOEpatents

Sadrozinski, Hartmut F. W.; Seiden, Abraham; Cartiglia, Nicolo

2017-04-04

Position sensitive radiation detection is provided using a continuous electrode in a semiconductor radiation detector, as opposed to the conventional use of a segmented electrode. Time constants relating to AC coupling between the continuous electrode and segmented contacts to the electrode are selected to provide position resolution from the resulting configurations. The resulting detectors advantageously have a more uniform electric field than conventional detectors having segmented electrodes, and are expected to have much lower cost of production and of integration with readout electronics.

A New Approach to an Old Technique-The S.U.T.R. First Technique.

PubMed

Jones, Frank; Lewis, Catherine; Knight, Darryl; Bacon, Louise; Patel, Vijay; Moore, Carolyn

2018-04-01

Ventral and incisional hernias of the abdominal wall are common problems treated by surgeons around the globe. Incisional hernias are common postoperative complications of abdominal laparotomies with a reported incidence of up to 20 per cent. The increasing use of prosthetic mesh in open ventral hernia repairs necessitated the development of different operative techniques used in the repairs. It also required that surgeons become facile with placement of the mesh in different anatomical positions on the abdominal wall. One of the most common locations is placement of the mesh in the underlay position. Many surgeons who use the underlay technique have expressed significant concerns. Among these are fear of an inadvertent bowel injury while placing the mesh, poor visualization during mesh placement, and the inability to use the underlay technique for difficult hernias. We present a very useful, if not, novel technique of open hernia repair using mesh in the underlay position that helps to 1) prevent complications, 2) facilitate easier mesh fixation, 3) simplify open repair of atypical ventral hernias, and 4) reduce total operative time while still adhering to the important fundamental principles of a tension-free hernia repair. This technique as we describe it has been compared with the old parachute technique, but we think this is a significant improvement of that seldom used technique. We believe the use of this technique for the underlay position makes open ventral hernia repair safer, faster, and easier; however, our goal for this article is to describe the procedure in detail. In addition, we recently have started using this technique to fix the mesh when doing the retrorectus approach as well.

Large-area PSPMT based gamma-ray imager with edge reclamation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ziock, K-P; Nakae, L

2000-09-21

We describe a coded aperture, gamma-ray imager which uses a CsI(Na) scintillator coupled to an Hamamatsu R3292 position-sensitive photomultiplier tube (PSPMT) as the position-sensitive detector. We have modified the normal resistor divider readout of the PSPMT to allow use of nearly the full 10 cm diameter active area of the PSPMT with a single scintillator crystal one centimeter thick. This is a significant performance improvement over that obtained with the standard readout technique where the linearity and position resolution start to degrade at radii as small as 3.5 cm with a crystal 0.75 crn thick. This represents a recovery ofmore » over 60% of the PSPMT active area. The performance increase allows the construction of an imager with a field of view 20 resolution elements in diameter with useful quantum efficiency from 60-700 keV. In this paper we describe the readout technique, its implementation in a coded aperture imager and the performance of that imager.« less

A reconfigurable image tube using an external electronic image readout

NASA Astrophysics Data System (ADS)

Lapington, J. S.; Howorth, J. R.; Milnes, J. S.

2005-08-01

We have designed and built a sealed tube microchannel plate (MCP) intensifier for optical/NUV photon counting applications suitable for 18, 25 and 40 mm diameter formats. The intensifier uses an electronic image readout to provide direct conversion of event position into electronic signals, without the drawbacks associated with phosphor screens and subsequent optical detection. The Image Charge technique is used to remove the readout from the intensifier vacuum enclosure, obviating the requirement for additional electrical vacuum feedthroughs and for the readout pattern to be UHV compatible. The charge signal from an MCP intensifier is capacitively coupled via a thin dielectric vacuum window to the electronic image readout, which is external to the sealed intensifier tube. The readout pattern is a separate item held in proximity to the dielectric window and can be easily detached, making the system easily reconfigurable. Since the readout pattern detects induced charge and is external to the tube, it can be constructed as a multilayer, eliminating the requirement for narrow insulator gaps and allowing it to be constructed using standard PCB manufacturing tolerances. We describe two readout patterns, the tetra wedge anode (TWA), an optimized 4 electrode device similar to the wedge and strip anode (WSA) but with a factor 2 improvement in resolution, and an 8 channel high speed 50 ohm device, both manufactured as multilayer PCBs. We present results of the detector imaging performance, image resolution, linearity and stability, and discuss the development of an integrated readout and electronics device based on these designs.

A rack-mounted precision waveguide-below-cutoff attenuator with an absolute electronic readout

NASA Technical Reports Server (NTRS)

Cook, C. C.

1974-01-01

A coaxial precision waveguide-below-cutoff attenuator is described which uses an absolute (unambiguous) electronic digital readout of displacement in inches in addition to the usual gear driven mechanical counter-dial readout in decibels. The attenuator is rack-mountable and has the input and output RF connectors in a fixed position. The attenuation rate for 55, 50, and 30 MHz operation is given along with a discussion of sources of errors. In addition, information is included to aid the user in making adjustments on the attenuator should it be damaged or disassembled for any reason.

Event-related potential indices of workload in a single task paradigm

NASA Technical Reports Server (NTRS)

Horst, R. L.; Munson, R. C.; Ruchkin, D. S.

1984-01-01

Many previous studies of both behavioral and physiological correlates of cognitive workload have burdened subjects with a contrived secondary task in order to assess the workload of a primary task. The present study investigated event-related potential (ERP) indices of workload in a single task paradigm. Subjects monitored changing digital readouts for values that went 'out-of-bounds'. The amplitude of a long-latency positivity in the ERPs elicited by readout changes increased with the number of readouts being monitored. This effect of workload on ERPs is reported, along with plans for additional analyses to address theoretical implications.

Development of a multiplexed readout with high position resolution for positron emission tomography

NASA Astrophysics Data System (ADS)

Lee, Sangwon; Choi, Yong; Kang, Jihoon; Jung, Jin Ho

2017-04-01

Detector signals for positron emission tomography (PET) are commonly multiplexed to reduce the number of digital processing channels so that the system can remain cost effective while also maintaining imaging performance. In this work, a multiplexed readout combining Anger position estimation algorithm and position decoder circuit (PDC) was developed to reduce the number of readout channels by a factor of 24, 96-to-4. The data acquisition module consisted of a TDC (50 ps resolution), 4-channel ADCs (12 bit, 105 MHz sampling rate), 2 GB SDRAM and USB3.0. The performance of the multiplexed readout was assessed with a high-resolution PET detector block composed of 2×3 detector modules, each consisting of an 8×8 array of 1.52×1.52×6 mm3 LYSO, a 4×4 array of 3×3 mm2 silicon photomultiplier (SiPM) and 13.4×13.4 mm2 light guide with 0.7 mm thickness. The acquired flood histogram showed that all 384 crystals could be resolved. The average energy resolution at 511 keV was 13.7±1.6% full-width-at-half-maximum (FWHM) and the peak-to-valley ratios of the flood histogram on the horizontal and vertical lines were 18.8±0.8 and 22.8±1.3, respectively. The coincidence resolving time of a pair of detector blocks was 6.2 ns FWHM. The reconstructed phantom image showed that rods down to a diameter of 1.6 mm could be resolved. The results of this study indicate that the multiplexed readout would be useful in developing a PET with a spatial resolution less than the pixel size of the photosensor, such as a SiPM array.

Studies on fast triggering and high precision tracking with Resistive Plate Chambers

NASA Astrophysics Data System (ADS)

Aielli, G.; Ball, R.; Bilki, B.; Chapman, J. W.; Cardarelli, R.; Dai, T.; Diehl, E.; Dubbert, J.; Ferretti, C.; Feng, H.; Francis, K.; Guan, L.; Han, L.; Hou, S.; Levin, D.; Li, B.; Liu, L.; Paolozzi, L.; Repond, J.; Roloff, J.; Santonico, R.; Song, H. Y.; Wang, X. L.; Wu, Y.; Xia, L.; Xu, L.; Zhao, T.; Zhao, Z.; Zhou, B.; Zhu, J.

2013-06-01

We report on studies of fast triggering and high precision tracking using Resistive Plate Chambers (RPCs). Two beam tests were carried out with the 180 GeV/c muon beam at CERN using glass RPCs with gas gaps of 1.15 mm and equipped with readout strips with 1.27 mm pitch. This is the first beam test of RPCs with fine-pitch readout strips that explores precision tracking and triggering capabilities. RPC signals were acquired with precision timing and charge integrating readout electronics at both ends of the strips. The time resolution was measured to be better than 600 ps and the average spatial resolution was found to be 220 μm using charge information and 287 μm only using signal arrival time information. The dual-ended readout allows the determination of the average and the difference of the signal arrival times. The average time was found to be independent of the incident particle position along the strip and is useful for triggering purposes. The time difference yielded a determination of the hit position with a precision of 7.5 mm along the strip. These results demonstrate the feasibility using RPCs for fast and high-resolution triggering and tracking.

A GEM readout with radial zigzag strips and linear charge-sharing response

DOE PAGES

Zhang, Aiwu; Hohlmann, Marcus; Azmoun, Babak; ...

2018-01-10

Here, we study the position sensitivity of radial zigzag strips intended to read out large GEM detectors for tracking at future experiments. Zigzag strips can cover a readout area with fewer strips than regular straight strips while maintaining good spatial resolution. Consequently, they can reduce the number of required electronic channels and related cost for large-area GEM detector systems. A non-linear relation between incident particle position and hit position measured from charge sharing among zigzag strips was observed in a previous study. We significantly reduce this non-linearity by improving the interleaving of adjacent physical zigzag strips. Zigzag readout structures aremore » implemented on PCBs and on a flexible foil and are tested using a 10 cm × 10 cm triple-GEM detector scanned with a strongly collimated X-ray gun on a 2D motorized stage. Lastly, angular resolutions of 60–84 μrad are achieved with a 1.37 mrad angular strip pitch at a radius of 784 mm. On a linear scale this corresponds to resolutions below 100 μm.« less

A GEM readout with radial zigzag strips and linear charge-sharing response

NASA Astrophysics Data System (ADS)

Zhang, Aiwu; Hohlmann, Marcus; Azmoun, Babak; Purschke, Martin L.; Woody, Craig

2018-04-01

We study the position sensitivity of radial zigzag strips intended to read out large GEM detectors for tracking at future experiments. Zigzag strips can cover a readout area with fewer strips than regular straight strips while maintaining good spatial resolution. Consequently, they can reduce the number of required electronic channels and related cost for large-area GEM detector systems. A non-linear relation between incident particle position and hit position measured from charge sharing among zigzag strips was observed in a previous study. We significantly reduce this non-linearity by improving the interleaving of adjacent physical zigzag strips. Zigzag readout structures are implemented on PCBs and on a flexible foil and are tested using a 10 cm × 10 cm triple-GEM detector scanned with a strongly collimated X-ray gun on a 2D motorized stage. Angular resolutions of 60-84 μrad are achieved with a 1.37 mrad angular strip pitch at a radius of 784 mm. On a linear scale this corresponds to resolutions below 100 μm.

AXAF VETA-I mirror encircled energy measurements and data reduction

NASA Technical Reports Server (NTRS)

Zhao, Ping; Freeman, Mark D.; Hughes, John P.; Kellogg, Edwin M.; Nguyen, Dan T.; Joy, Marshall; Kolodziejczak, Jeffery J.

1992-01-01

The AXAF VETA-I mirror encircled energy was measured with a series of apertures and two flow gas proportional counters at five X-ray energies ranging from 0.28 to 2.3 keV. The proportional counter has a thin plastic window with an opaque wire mesh supporting grid. Depending on the counter position, this mesh can cause the X-ray transmission to vary as much as +/-9 percent, which directly translates into an error in the encircled energy. In order to correct this wire mesh effect, window scan measurements were made, in which the counter was scanned in both horizontal (Y) and vertical (Z) directions with the aperture fixed. Post VETA measurement of the VXDS setup were made to determine the exact geometry and position of the mesh grid. Computer models of the window mesh were developed to simulate the X-ray transmission based on this measurement. The window scan data were fitted to such mesh models and corrections were made. After this study, the mesh effect was well understood and the final results of the encircled energy were obtained with an uncertainty of less than 0.8 percent.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snyder, L.; Manning, B.; Bowden, N. S.

The MICROMEGAS (MICRO-MEsh GAseous Structure) charge amplification structure has found wide use in many detection applications, especially as a gain stage for the charge readout of Time Projection Chambers (TPCs). We report on the behavior of a MICROMEGAS TPC when operated in a high-energy (up to 800 MeV) neutron beam. It is found that neutron-induced reactions can cause discharges in some drift gas mixtures that are stable in the absence of the neutron beam. The discharges result from recoil ions close to the MICROMEGAS that deposit high specific ionization density and have a limited diffusion time. And for a binarymore » drift gas, increasing the percentage of the molecular component (quench gas) relative to the noble component and operating at lower pressures generally improves stability.« less

A weak Galerkin least-squares finite element method for div-curl systems

NASA Astrophysics Data System (ADS)

Li, Jichun; Ye, Xiu; Zhang, Shangyou

2018-06-01

In this paper, we introduce a weak Galerkin least-squares method for solving div-curl problem. This finite element method leads to a symmetric positive definite system and has the flexibility to work with general meshes such as hybrid mesh, polytopal mesh and mesh with hanging nodes. Error estimates of the finite element solution are derived. The numerical examples demonstrate the robustness and flexibility of the proposed method.

Theoretical Noise Analysis on a Position-sensitive Metallic Magnetic Calorimeter

NASA Technical Reports Server (NTRS)

Smith, Stephen J.

2007-01-01

We report on the theoretical noise analysis for a position-sensitive Metallic Magnetic Calorimeter (MMC), consisting of MMC read-out at both ends of a large X-ray absorber. Such devices are under consideration as alternatives to other cryogenic technologies for future X-ray astronomy missions. We use a finite-element model (FEM) to numerically calculate the signal and noise response at the detector outputs and investigate the correlations between the noise measured at each MMC coupled by the absorber. We then calculate, using the optimal filter concept, the theoretical energy and position resolution across the detector and discuss the trade-offs involved in optimizing the detector design for energy resolution, position resolution and count rate. The results show, theoretically, the position-sensitive MMC concept offers impressive spectral and spatial resolving capabilities compared to pixel arrays and similar position-sensitive cryogenic technologies using Transition Edge Sensor (TES) read-out.

The impact of hydrophobic hernia mesh coating by omega fatty acid on atraumatic fibrin sealant fixation.

PubMed

Gruber-Blum, S; Brand, J; Keibl, C; Redl, H; Fortelny, R H; May, C; Petter-Puchner, A H

2015-08-01

Fibrin sealant (FS) is a safe and efficient fixation method in open intraperitoneal hernia repair. While favourable results have been achieved with hydrophilic meshes, hydrophobic (such as Omega fatty acid coated) meshes (OFM) have not been specifically assessed so far. Atrium C-qur lite(®) mesh was tested in rats in models of open onlay and intraperitoneal hernia repair. 44 meshes (2 × 2 cm) were implanted in 30 male Sprague-Dawley rats in open (n = 2 meshes per animal) and intraperitoneal technique (IPOM; n = 1 mesh per animal). Animals were randomised to four groups: onlay and IPOM sutured vs. sealed. Follow-up was 6 weeks, sutured groups serving as controls. Evaluation criteria were mesh dislocation, adhesions and foreign body reaction. FS provided a reliable fixation in onlay technique, whereas OFM meshes dislocated in the IPOM position when sealed only. FS mesh fixation was safe with OFM meshes in open onlay repair. Intraperitoneal placement of hydrophobic meshes requires additional fixation and cannot be achieved with FS alone.

The use of workflows in the design and implementation of complex experiments in macromolecular crystallography.

PubMed

Brockhauser, Sandor; Svensson, Olof; Bowler, Matthew W; Nanao, Max; Gordon, Elspeth; Leal, Ricardo M F; Popov, Alexander; Gerring, Matthew; McCarthy, Andrew A; Gotz, Andy

2012-08-01

The automation of beam delivery, sample handling and data analysis, together with increasing photon flux, diminishing focal spot size and the appearance of fast-readout detectors on synchrotron beamlines, have changed the way that many macromolecular crystallography experiments are planned and executed. Screening for the best diffracting crystal, or even the best diffracting part of a selected crystal, has been enabled by the development of microfocus beams, precise goniometers and fast-readout detectors that all require rapid feedback from the initial processing of images in order to be effective. All of these advances require the coupling of data feedback to the experimental control system and depend on immediate online data-analysis results during the experiment. To facilitate this, a Data Analysis WorkBench (DAWB) for the flexible creation of complex automated protocols has been developed. Here, example workflows designed and implemented using DAWB are presented for enhanced multi-step crystal characterizations, experiments involving crystal reorientation with kappa goniometers, crystal-burning experiments for empirically determining the radiation sensitivity of a crystal system and the application of mesh scans to find the best location of a crystal to obtain the highest diffraction quality. Beamline users interact with the prepared workflows through a specific brick within the beamline-control GUI MXCuBE.

Stretchable Mesh for Cavity Noise Reduction

NASA Technical Reports Server (NTRS)

Khorrami, Mehdi R. (Inventor)

2017-01-01

A stretchable mesh material extends across the opening of a cavity of the landing gear of an aircraft when the landing gear is in the deployed position. The mesh material alters the flow of air across the opening of the landing gear cavity and significantly reduces the amount of noise produced by the wheel well at low-to-mid frequencies.

Single Crystal Diamond Beam Position Monitors with Radiofrequency Electronic Readout

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solar, B.; Graafsma, H.; Potdevin, G.

2010-06-23

Over the energy range 5{approx}30 keV a suitably contacted, thin ({approx}100 {mu}m) diamond plate can be operated in situ as a continuous monitor of X-ray beam intensity and position as the diamond absorbs only a small percentage of the incident beam. Single crystal diamond is a completely homogeneous material showing fast (ns), spatially uniform signal response and negligible (

Test beam studies of the light yield, time and coordinate resolutions of scintillator strips with WLS fibers and SiPM readout

DOE PAGES

Denisov, Dmitri; Evdokimov, Valery; Lukic, Strahinja; ...

2016-12-24

Prototype scintilator+WLS strips with SiPM readout for large muon detection systems were tested in the muon beam of the Fermilab Test Beam Facility. Furthermore, light yield of up to 137 photoelectrons per muon per strip has been observed, as well as time resolution of 330 ps and position resolution along the strip of 5.4 cm.

Dispersive Readout of Adiabatic Phases

NASA Astrophysics Data System (ADS)

Kohler, Sigmund

2017-11-01

We propose a protocol for the measurement of adiabatic phases of periodically driven quantum systems coupled to an open cavity that enables dispersive readout. It turns out that the cavity transmission exhibits peaks at frequencies determined by a resonance condition that involves the dynamical and the geometric phase. Since these phases scale differently with the driving frequency, one can determine them by fitting the peak positions to the theoretically expected behavior. For the derivation of the resonance condition and for a numerical study, we develop a Floquet theory for the dispersive readout of ac driven quantum systems. The feasibility is demonstrated for two test cases that generalize Landau-Zener-Stückelberg-Majorana interference to two-parameter driving.

CCD image sensor induced error in PIV applications

NASA Astrophysics Data System (ADS)

Legrand, M.; Nogueira, J.; Vargas, A. A.; Ventas, R.; Rodríguez-Hidalgo, M. C.

2014-06-01

The readout procedure of charge-coupled device (CCD) cameras is known to generate some image degradation in different scientific imaging fields, especially in astrophysics. In the particular field of particle image velocimetry (PIV), widely extended in the scientific community, the readout procedure of the interline CCD sensor induces a bias in the registered position of particle images. This work proposes simple procedures to predict the magnitude of the associated measurement error. Generally, there are differences in the position bias for the different images of a certain particle at each PIV frame. This leads to a substantial bias error in the PIV velocity measurement (˜0.1 pixels). This is the order of magnitude that other typical PIV errors such as peak-locking may reach. Based on modern CCD technology and architecture, this work offers a description of the readout phenomenon and proposes a modeling for the CCD readout bias error magnitude. This bias, in turn, generates a velocity measurement bias error when there is an illumination difference between two successive PIV exposures. The model predictions match the experiments performed with two 12-bit-depth interline CCD cameras (MegaPlus ES 4.0/E incorporating the Kodak KAI-4000M CCD sensor with 4 megapixels). For different cameras, only two constant values are needed to fit the proposed calibration model and predict the error from the readout procedure. Tests by different researchers using different cameras would allow verification of the model, that can be used to optimize acquisition setups. Simple procedures to obtain these two calibration values are also described.

Technique for positioning hologram for balancing large data capacity with fast readout

NASA Astrophysics Data System (ADS)

Shimada, Ken-ichi; Hosaka, Makoto; Yamazaki, Kazuyoshi; Onoe, Shinsuke; Ide, Tatsuro

2017-09-01

The technical difficulty of balancing large data capacity with a high data transfer rate in holographic data storage systems (HDSSs) is significantly high because of tight tolerances for physical perturbation. From a system margin perspective in terabyte-class HDSSs, the positioning error of a holographic disc should be within about 10 µm to ensure high readout quality. Furthermore, fine control of the positioning should be accomplished within a time frame of about 10 ms for a high data transfer rate of the Gbps class, while a conventional method based on servo control of spindle or sled motors can rarely satisfy the requirement. In this study, a new compensation method for the effect of positioning error, which precisely controls the positioning of a Nyquist aperture instead of a holographic disc, has been developed. The method relaxes the markedly low positional tolerance of a holographic disc. Moreover, owing to the markedly light weight of the aperture, positioning control within the required time frame becomes feasible.

A heterodyne interferometer for high resolution translation and tilt measurement as optical readout for the LISA inertial sensor

NASA Astrophysics Data System (ADS)

Schuldt, Thilo; Kraus, Hans-Jürgen; Weise, Dennis; Braxmaier, Claus; Peters, Achim; Johann, Ulrich

2017-11-01

The space-based gravitational wave detector LISA (Laser Interferometer Space Antenna) requires a high performance position sensor in order to measure the translation and tilt of the free flying test mass with respect to the LISA optical bench. Here, we present a mechanically highly stable and compact setup of a heterodyne interferometer combined with differential wavefront sensing for the tilt measurement which serves as a demonstrator for an optical readout of the LISA test mass position. First results show noise levels below 1 nm/√Hz and 1 μrad/√Hz, respectively, for frequencies < 10-3 Hz.

Hit Dexter: A Machine-Learning Model for the Prediction of Frequent Hitters.

PubMed

Stork, Conrad; Wagner, Johannes; Friedrich, Nils-Ole; de Bruyn Kops, Christina; Šícho, Martin; Kirchmair, Johannes

2018-03-20

False-positive assay readouts caused by badly behaving compounds-frequent hitters, pan-assay interference compounds (PAINS), aggregators, and others-continue to pose a major challenge to experimental screening. There are only a few in silico methods that allow the prediction of such problematic compounds. We report the development of Hit Dexter, two extremely randomized trees classifiers for the prediction of compounds likely to trigger positive assay readouts either by true promiscuity or by assay interference. The models were trained on a well-prepared dataset extracted from the PubChem Bioassay database, consisting of approximately 311 000 compounds tested for activity on at least 50 proteins. Hit Dexter reached MCC and AUC values of up to 0.67 and 0.96 on an independent test set, respectively. The models are expected to be of high value, in particular to medicinal chemists and biochemists who can use Hit Dexter to identify compounds for which extra caution should be exercised with positive assay readouts. Hit Dexter is available as a free web service at http://hitdexter.zbh. uni-hamburg.de. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mesh morphing for finite element analysis of implant positioning in cementless total hip replacements.

PubMed

Bah, Mamadou T; Nair, Prasanth B; Browne, Martin

2009-12-01

Finite element (FE) analysis of the effect of implant positioning on the performance of cementless total hip replacements (THRs) requires the generation of multiple meshes to account for positioning variability. This process can be labour intensive and time consuming as CAD operations are needed each time a specific orientation is to be analysed. In the present work, a mesh morphing technique is developed to automate the model generation process. The volume mesh of a baseline femur with the implant in a nominal position is deformed as the prosthesis location is varied. A virtual deformation field, obtained by solving a linear elasticity problem with appropriate boundary conditions, is applied. The effectiveness of the technique is evaluated using two metrics: the percentages of morphed elements exceeding an aspect ratio of 20 and an angle of 165 degrees between the adjacent edges of each tetrahedron. Results show that for 100 different implant positions, the first and second metrics never exceed 3% and 3.5%, respectively. To further validate the proposed technique, FE contact analyses are conducted using three selected morphed models to predict the strain distribution in the bone and the implant micromotion under joint and muscle loading. The entire bone strain distribution is well captured and both percentages of bone volume with strain exceeding 0.7% and bone average strains are accurately computed. The results generated from the morphed mesh models correlate well with those for models generated from scratch, increasing confidence in the methodology. This morphing technique forms an accurate and efficient basis for FE based implant orientation and stability analysis of cementless hip replacements.

Integrated starting and running amalgam assembly for an electrodeless fluorescent lamp

DOEpatents

Borowiec, Joseph Christopher; Cocoma, John Paul; Roberts, Victor David

1998-01-01

An integrated starting and running amalgam assembly for an electrodeless SEF fluorescent lamp includes a wire mesh amalgam support constructed to jointly optimize positions of a starting amalgam and a running amalgam in the lamp, thereby optimizing mercury vapor pressure in the lamp during both starting and steady-state operation in order to rapidly achieve and maintain high light output. The wire mesh amalgam support is constructed to support the starting amalgam toward one end thereof and the running amalgam toward the other end thereof, and the wire mesh is rolled for friction-fitting within the exhaust tube of the lamp. The positions of the starting and running amalgams on the wire mesh are jointly optimized such that high light output is achieved quickly and maintained, while avoiding any significant reduction in light output between starting and running operation.

Performance of a MICROMEGAS-based TPC in a high-energy neutron beam

NASA Astrophysics Data System (ADS)

Snyder, L.; Manning, B.; Bowden, N. S.; Bundgaard, J.; Casperson, R. J.; Cebra, D. A.; Classen, T.; Duke, D. L.; Gearhart, J.; Greife, U.; Hagmann, C.; Heffner, M.; Hensle, D.; Higgins, D.; Isenhower, D.; King, J.; Klay, J. L.; Geppert-Kleinrath, V.; Loveland, W.; Magee, J. A.; Mendenhall, M. P.; Sangiorgio, S.; Seilhan, B.; Schmitt, K. T.; Tovesson, F.; Towell, R. S.; Walsh, N.; Watson, S.; Yao, L.; Younes, W.

2018-02-01

The MICROMEGAS (MICRO-MEsh GAseous Structure) charge amplification structure has found wide use in many detection applications, especially as a gain stage for the charge readout of Time Projection Chambers (TPCs). Here we report on the behavior of a MICROMEGAS TPC when operated in a high-energy (up to 800 MeV) neutron beam. It is found that neutron-induced reactions can cause discharges in some drift gas mixtures that are stable in the absence of the neutron beam. The discharges result from recoil ions close to the MICROMEGAS that deposit high specific ionization density and have a limited diffusion time. For a binary drift gas, increasing the percentage of the molecular component (quench gas) relative to the noble component and operating at lower pressures generally improves stability.

Analysis of de-noising methods to improve the precision of the ILSF BPM electronic readout system

NASA Astrophysics Data System (ADS)

Shafiee, M.; Feghhi, S. A. H.; Rahighi, J.

2016-12-01

In order to have optimum operation and precise control system at particle accelerators, it is required to measure the beam position with the precision of sub-μm. We developed a BPM electronic readout system at Iranian Light Source Facility and it has been experimentally tested at ALBA accelerator facility. The results show the precision of 0.54 μm in beam position measurements. To improve the precision of this beam position monitoring system to sub-μm level, we have studied different de-noising methods such as principal component analysis, wavelet transforms, filtering by FIR, and direct averaging method. An evaluation of the noise reduction was given to testify the ability of these methods. The results show that the noise reduction based on Daubechies wavelet transform is better than other algorithms, and the method is suitable for signal noise reduction in beam position monitoring system.

Highly multiplexed signal readout for a time-of-flight positron emission tomography detector based on silicon photomultipliers.

PubMed

Cates, Joshua W; Bieniosek, Matthew F; Levin, Craig S

2017-01-01

Maintaining excellent timing resolution in the generation of silicon photomultiplier (SiPM)-based time-of-flight positron emission tomography (TOF-PET) systems requires a large number of high-speed, high-bandwidth electronic channels and components. To minimize the cost and complexity of a system's back-end architecture and data acquisition, many analog signals are often multiplexed to fewer channels using techniques that encode timing, energy, and position information. With progress in the development SiPMs having lower dark noise, after pulsing, and cross talk along with higher photodetection efficiency, a coincidence timing resolution (CTR) well below 200 ps FWHM is now easily achievable in single pixel, bench-top setups using 20-mm length, lutetium-based inorganic scintillators. However, multiplexing the output of many SiPMs to a single channel will significantly degrade CTR without appropriate signal processing. We test the performance of a PET detector readout concept that multiplexes 16 SiPMs to two channels. One channel provides timing information with fast comparators, and the second channel encodes both position and energy information in a time-over-threshold-based pulse sequence. This multiplexing readout concept was constructed with discrete components to process signals from a [Formula: see text] array of SensL MicroFC-30035 SiPMs coupled to [Formula: see text] Lu 1.8 Gd 0.2 SiO 5 (LGSO):Ce (0.025 mol. %) scintillators. This readout method yielded a calibrated, global energy resolution of 15.3% FWHM at 511 keV with a CTR of [Formula: see text] FWHM between the 16-pixel multiplexed detector array and a [Formula: see text] LGSO-SiPM reference detector. In summary, results indicate this multiplexing scheme is a scalable readout technique that provides excellent coincidence timing performance.

Characterization of an ultraviolet imaging detector with high event rate ROIC (HEROIC) readout

NASA Astrophysics Data System (ADS)

Nell, Nicholas; France, Kevin; Harwit, Alex; Bradley, Scott; Franka, Steve; Freymiller, Ed; Ebbets, Dennis

2016-07-01

We present characterization results from a photon counting imaging detector consisting of one microchannel plate (MCP) and an array of two readout integrated circuits (ROIC) that record photon position. The ROICs used in the position readout are the high event rate ROIC (HEROIC) devices designed to handle event rates up to 1 MHz per pixel, recently developed by the Ball Aerospace and Technologies Corporation in collaboration with the University of Colorado. An opaque cesium iodide (CsI) photocathode sensitive in the far-ultraviolet (FUV; 122-200 nm), is deposited on the upper surface of the MCP. The detector is characterized in a chamber developed by CU Boulder that is capable of illumination with vacuum-ultraviolet (VUV) monochromatic light and measurement of absolute ux with a calibrated photodiode. Testing includes investigation of the effects of adjustment of internal settings of the HEROIC devices including charge threshold, gain, and amplifier bias. The detector response to high count rates is tested. We report initial results including background, uniformity, and quantum detection efficiency (QDE) as a function of wavelength.

Absolute Position Encoders With Vertical Image Binning

NASA Technical Reports Server (NTRS)

Leviton, Douglas B.

2005-01-01

Improved optoelectronic patternrecognition encoders that measure rotary and linear 1-dimensional positions at conversion rates (numbers of readings per unit time) exceeding 20 kHz have been invented. Heretofore, optoelectronic pattern-recognition absoluteposition encoders have been limited to conversion rates <15 Hz -- too low for emerging industrial applications in which conversion rates ranging from 1 kHz to as much as 100 kHz are required. The high conversion rates of the improved encoders are made possible, in part, by use of vertically compressible or binnable (as described below) scale patterns in combination with modified readout sequences of the image sensors [charge-coupled devices (CCDs)] used to read the scale patterns. The modified readout sequences and the processing of the images thus read out are amenable to implementation by use of modern, high-speed, ultra-compact microprocessors and digital signal processors or field-programmable gate arrays. This combination of improvements makes it possible to greatly increase conversion rates through substantial reductions in all three components of conversion time: exposure time, image-readout time, and image-processing time.

Pixel electronic noise as a function of position in an active matrix flat panel imaging array

NASA Astrophysics Data System (ADS)

Yazdandoost, Mohammad Y.; Wu, Dali; Karim, Karim S.

2010-04-01

We present an analysis of output referred pixel electronic noise as a function of position in the active matrix array for both active and passive pixel architectures. Three different noise sources for Active Pixel Sensor (APS) arrays are considered: readout period noise, reset period noise and leakage current noise of the reset TFT during readout. For the state-of-the-art Passive Pixel Sensor (PPS) array, the readout noise of the TFT switch is considered. Measured noise results are obtained by modeling the array connections with RC ladders on a small in-house fabricated prototype. The results indicate that the pixels in the rows located in the middle part of the array have less random electronic noise at the output of the off-panel charge amplifier compared to the ones in rows at the two edges of the array. These results can help optimize for clearer images as well as help define the region-of-interest with the best signal-to-noise ratio in an active matrix digital flat panel imaging array.

Tracking performance of a single-crystal and a polycrystalline diamond pixel-detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menasce, D.; et al.

2013-06-01

We present a comparative characterization of the performance of a single-crystal and a polycrystalline diamond pixel-detector employing the standard CMS pixel readout chips. Measurements were carried out at the Fermilab Test Beam Facility, FTBF, using protons of momentum 120 GeV/c tracked by a high-resolution pixel telescope. Particular attention was directed to the study of the charge-collection, the charge-sharing among adjacent pixels and the achievable position resolution. The performance of the single-crystal detector was excellent and comparable to the best available silicon pixel-detectors. The measured average detection-efficiency was near unity, ε = 0.99860±0.00006, and the position-resolution for shared hits was aboutmore » 6 μm. On the other hand, the performance of the polycrystalline detector was hampered by its lower charge collection distance and the readout chip threshold. A new readout chip, capable of operating at much lower threshold (around 1 ke $-$), would be required to fully exploit the potential performance of the polycrystalline diamond pixel-detector.« less

Theory and Development of Position-Sensitive Quantum Calorimeters. Degree awarded by Stanford Univ.

NASA Technical Reports Server (NTRS)

Figueroa-Feliciano, Enectali; White, Nicholas E. (Technical Monitor)

2001-01-01

Quantum calorimeters are being developed as imaging spectrometers for future X-ray astrophysics observatories. Much of the science to be done by these instruments could benefit greatly from larger focal-plane coverage of the detector (without increasing pixel size). An order of magnitude more area will greatly increase the science throughput of these future instruments. One of the main deterrents to achieving this goal is the complexity of the readout schemes involved. We have devised a way to increase the number of pixels from the current baseline designs by an order of magnitude without increasing the number of channels required for readout. The instrument is a high energy resolution, distributed-readout imaging spectrometer called a Position-Sensitive Transition-Edge Sensor (POST). A POST is a quantum calorimeter consisting of two Transition-Edge Sensors (TESS) on the ends of a long absorber capable of one-dimensional imaging spectroscopy. Comparing rise time and energy information from the two TESS, the position of the event in the POST is determined. The energy of the event is inferred from the sum of the two pulses. We have developed a generalized theoretical formalism for distributed-readout calorimeters and apply it to our devices. We derive the noise theory and calculate the theoretical energy resolution of a POST. Our calculations show that a 7-pixel POST with 6 keV saturation energy can achieve 2.3 eV resolution, making this a competitive design for future quantum calorimeter instruments. For this thesis we fabricated 7- and 15-pixel POSTS using Mo/Au TESs and gold absorbers, and moved from concept drawings on scraps of napkins to a 32 eV energy resolution at 1.5 keV, 7-pixel POST calorimeter.

Analysis of the readout of a high rate MWPC

NASA Astrophysics Data System (ADS)

Camerini, P.; Grion, N.; Rui, R.; Sheffer, G.; Openshaw, R.

1990-06-01

An analytical method to reduce the raw data supplied by a high-speed multiwire proportional chamber (MWPC) is presented. The results obtained with the MWPC and the associated readout system, LeCroy PCOS III, when monitoring a high-intensity flux of positive pions delivered by the M11 channel at TRIUMF are discussed. The method allows the flux intensity, the beam envelope and the detector efficiency to be determined with little uncertainty (few %) at intense particle beams ( > 10 7 particles/s).

Readout characteristics of a minute aperture-mounted optical head slider flying above a submicron wide metal patterned medium track

NASA Astrophysics Data System (ADS)

Ohkubo, Toshifumi; Hirota, Terunao; Oumi, Manabu; Hirata, Masakazu; Nakajima, Kunio

2004-10-01

Advances in a digital network society require both higher densities and higher transfer rates in all sorts of storage devices. In optical recording, the trend toward higher recording density and larger storage capacity requires novel surface recording technologies that would drastically improve recording density. To satisfy these severe requirements, we have already proposed a compact integrated optical head slider assembly for proximity optical recording based on the "near field principle". Using the optical head slider, we have successfully demonstrated readout signals from 200 to 150-nm-long bit patterns at frequency bands up to approximately 10 MHz. However, from the practical point of view, it is quite necessary to evaluate readout signals from patterns of smaller (sub-micron to sub-sub-micron) track width in order to prove high-density recording potential. In this paper, we have investigated tracking accuracy characteristics utilizing sub-micron sized alternate patterns of 1-mm length formed in a straight line in the circumferential direction of the medium. Arranging precisely the head's relative position to these recorded patterns, we have successfully obtained readout signals just crossing the sub-micron line-and-space pattern's boundaries. Assuming that an aperture runs along an accurate trajectory of the arc of a circle, readout signal amplitude variations when crossing the pattern edge at a right angle have precisely predicted. Also, the influences of track width on maximum readout signal intensity and tracking sensitivity are discussed in detail.

Pitfalls in retromuscular mesh repair for incisional hernia: the importance of the "fatty triangle".

PubMed

Conze, J; Prescher, A; Klinge, U; Saklak, M; Schumpelick, V

2004-08-01

Open retromuscular mesh repair has become a standard procedure in incisional hernia repair. This technique led to a significant decrease of recurrences. Recurrences after this technique typically occur at the upper mesh border and are a result of the technical complexity of reaching the postulated underlay of 5 cm in the region of the linea alba. We performed an anatomical study in human corpses to investigate the abdominal wall with its different structures, with emphasis on the overlap of the mesh under the linea alba. The overlap can be achieved by incision of the posterior lamina of the rectus sheath, on both sides close to the linea alba. The incision opens the preperitoneal space and appears in the shape of a "fatty triangle". The anterior lamina of the rectus sheath above the hernia defect remains intact and facilitates a sufficient thrust bearing for a retromuscular mesh implantation. Knowledge of the anatomy and preparation of the "fatty triangle" enables a mesh positioning according to the principles of retromuscular mesh repair.

Performance of a MICROMEGAS-based TPC in a high-energy neutron beam

DOE PAGES

Snyder, L.; Manning, B.; Bowden, N. S.; ...

2017-11-01

The MICROMEGAS (MICRO-MEsh GAseous Structure) charge amplification structure has found wide use in many detection applications, especially as a gain stage for the charge readout of Time Projection Chambers (TPCs). We report on the behavior of a MICROMEGAS TPC when operated in a high-energy (up to 800 MeV) neutron beam. It is found that neutron-induced reactions can cause discharges in some drift gas mixtures that are stable in the absence of the neutron beam. The discharges result from recoil ions close to the MICROMEGAS that deposit high specific ionization density and have a limited diffusion time. And for a binarymore » drift gas, increasing the percentage of the molecular component (quench gas) relative to the noble component and operating at lower pressures generally improves stability.« less

The continuing challenge of parastomal hernia: failure of a novel polypropylene mesh repair.

PubMed Central

Morris-Stiff, G.; Hughes, L. E.

1998-01-01

In an attempt to reduce the high recurrence rate after repair of parastomal hernia, a technique was devised in which non-absorbable mesh was used to provide a permanent closure of the gap between the emerging bowel and abdominal wall. Seven patients were treated during the period 1990-1992. Five-year follow-up has given disappointing results, with recurrent hernia in 29% of cases and serious complications, including obstruction and dense adhesions to the intra-abdominal mesh, in 57% and a mesh-related abscess in 15% of cases. This study highlights a dual problem--failure of a carefully sutured mesh to maintain an occlusive position, and complications of the mesh itself. The poor results obtained with this technique together with the disappointing results with other methods described in the literature confirms that parastomal hernia presents a continuing challenge. Images Figure 1 Figure 2 PMID:9682640

Fast readout algorithm for cylindrical beam position monitors providing good accuracy for particle bunches with large offsets

NASA Astrophysics Data System (ADS)

Thieberger, P.; Gassner, D.; Hulsart, R.; Michnoff, R.; Miller, T.; Minty, M.; Sorrell, Z.; Bartnik, A.

2018-04-01

A simple, analytically correct algorithm is developed for calculating "pencil" relativistic beam coordinates using the signals from an ideal cylindrical particle beam position monitor (BPM) with four pickup electrodes (PUEs) of infinitesimal widths. The algorithm is then applied to simulations of realistic BPMs with finite width PUEs. Surprisingly small deviations are found. Simple empirically determined correction terms reduce the deviations even further. The algorithm is then tested with simulations for non-relativistic beams. As an example of the data acquisition speed advantage, a Field Programmable Gate Array-based BPM readout implementation of the new algorithm has been developed and characterized. Finally, the algorithm is tested with BPM data from the Cornell Preinjector.

Fast readout algorithm for cylindrical beam position monitors providing good accuracy for particle bunches with large offsets

DOE PAGES

Thieberger, Peter; Gassner, D.; Hulsart, R.; ...

2018-04-25

Here, a simple, analytically correct algorithm is developed for calculating “pencil” relativistic beam coordinates using the signals from an ideal cylindrical particle beam position monitor (BPM) with four pickup electrodes (PUEs) of infinitesimal widths. The algorithm is then applied to simulations of realistic BPMs with finite width PUEs. Surprisingly small deviations are found. Simple empirically determined correction terms reduce the deviations even further. The algorithm is then tested with simulations for non-relativistic beams. As an example of the data acquisition speed advantage, a FPGA-based BPM readout implementation of the new algorithm has been developed and characterized. Lastly, the algorithm ismore » tested with BPM data from the Cornell Preinjector.« less

Fast readout algorithm for cylindrical beam position monitors providing good accuracy for particle bunches with large offsets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thieberger, Peter; Gassner, D.; Hulsart, R.

Here, a simple, analytically correct algorithm is developed for calculating “pencil” relativistic beam coordinates using the signals from an ideal cylindrical particle beam position monitor (BPM) with four pickup electrodes (PUEs) of infinitesimal widths. The algorithm is then applied to simulations of realistic BPMs with finite width PUEs. Surprisingly small deviations are found. Simple empirically determined correction terms reduce the deviations even further. The algorithm is then tested with simulations for non-relativistic beams. As an example of the data acquisition speed advantage, a FPGA-based BPM readout implementation of the new algorithm has been developed and characterized. Lastly, the algorithm ismore » tested with BPM data from the Cornell Preinjector.« less

Fast readout algorithm for cylindrical beam position monitors providing good accuracy for particle bunches with large offsets.

PubMed

Thieberger, P; Gassner, D; Hulsart, R; Michnoff, R; Miller, T; Minty, M; Sorrell, Z; Bartnik, A

2018-04-01

A simple, analytically correct algorithm is developed for calculating "pencil" relativistic beam coordinates using the signals from an ideal cylindrical particle beam position monitor (BPM) with four pickup electrodes (PUEs) of infinitesimal widths. The algorithm is then applied to simulations of realistic BPMs with finite width PUEs. Surprisingly small deviations are found. Simple empirically determined correction terms reduce the deviations even further. The algorithm is then tested with simulations for non-relativistic beams. As an example of the data acquisition speed advantage, a Field Programmable Gate Array-based BPM readout implementation of the new algorithm has been developed and characterized. Finally, the algorithm is tested with BPM data from the Cornell Preinjector.

The performance of a wire mesh collimator SPECT camera for different breast volumes in prone position

NASA Astrophysics Data System (ADS)

Roslan, R. E.; Saad, W. H. Mohd; Saripan, M. I.; Hashim, S.; Choong, W.-S.

2010-07-01

The multihole collimator is the most commonly used collimator in conventional SPECT cameras for general purpose imaging. However, there are some limitations with this collimator, which includes the lack of sensitivity as a trade-off for obtaining better spatial resolution. This paper looks at the performance of a wire mesh collimator that was introduced recently in order to improve the ability of SPECT cameras in mapping breast cancer cells, utilizing the Technetium-99 m 140 keV radiotracer. In this work, various volumes of breast are modelled and simulated using Monte Carlo N-Particle (MCNP5) code, derived based on the real cup sizes and volumes in prone position. The size of tumour is 1 cm in diameter with tumour to background ratios (TBRs) ranging between TBR from 1:1 to TBR 20:1, and located 2 cm inside breast skin. The results show that wire mesh collimator 1 (WM-1) has the highest sensitivity and signal to noise ratio (SNR) in comparison with wire mesh collimator 2 (WM-2) and the multihole collimator (MHC). This indicates the potential of using a wire mesh collimator for early mapping of breast cancer cells.

Polypropylene Mesh Sling for Stress Urinary Incontinence: Does Memory Shaping of the Polypropylene Mesh Matter?

PubMed

Doering, Andrew; Azadi, Ali; Doering, David; Ostergard, Donald R

2017-12-22

We report a case of a mid-urethral sling (Advantage Fit™, Boston Scientific Corporation, Marlborough, Massachusetts) freshly removed from its original package. Upon removal from the packaging, the sling was noted to have a deformation in positioning at the midpoint, with curvature opposite the natural curve of the sling in the body. The images show the comparison to a sling with the desired positioning. Mid-urethral slings are commonly made from polypropylene mesh which has memory properties. It is important that manufacturers ensure that any steps in the processing or packaging of slings do not result in changes in the shape of the sling that may have unknown impacts on its clinical outcome.

Bone resorption analysis of platelet-derived growth factor type BB application on collagen for bone grafts secured by titanium mesh over a pig jaw defect model

PubMed Central

Herford, Alan Scott; Cicciù, Marco

2012-01-01

Purpose: The aim of this investigation was to evaluate whether the addition of the platelet derived growth factor type BB (PDGF-BB) to a collagen matrix applied on a titanium mesh would favor healing and resorption onto the grafted bone. A histologic and radiographic study of two different groups (test and control) was performed. Designs: A surgical procedure was performed on 8 pigs to obtain 16 bilateral mandibular alveolar defects. All the defects were then reconstructed with a mixture of autogenous bovine bone using titanium mesh positioning. Two groups, with a total of 16 defects were created: The first to study collagen sponge and PDGF-BB and the second to control collagen only. The collagen matrix was positioned directly over the mesh and soft tissue was closed without tensions onto both groups without attempting to obtain primary closure. Possible exposure of the titanium mesh as well as the height and volume of the new bone was recorded. Results: New bone formation averaged about 6.68 mm in the test group studied; the control group had less regenerated bone at 4.62 mm. Conclusion: PDGF-BB addition to the collagen matrix induced a strong increase in hard and soft tissue healing and favored bone formation, reducing bone resorption even if the mesh was exposed. PMID:23833493

Universal ventricular coordinates: A generic framework for describing position within the heart and transferring data.

PubMed

Bayer, Jason; Prassl, Anton J; Pashaei, Ali; Gomez, Juan F; Frontera, Antonio; Neic, Aurel; Plank, Gernot; Vigmond, Edward J

2018-04-01

Being able to map a particular set of cardiac ventricles to a generic topologically equivalent representation has many applications, including facilitating comparison of different hearts, as well as mapping quantities and structures of interest between them. In this paper we describe Universal Ventricular Coordinates (UVC), which can be used to describe position within any biventricular heart. UVC comprise four unique coordinates that we have chosen to be intuitive, well defined, and relevant for physiological descriptions. We describe how to determine these coordinates for any volumetric mesh by illustrating how to properly assign boundary conditions and utilize solutions to Laplace's equation. Using UVC, we transferred scalar, vector, and tensor data between four unstructured ventricular meshes from three different species. Performing the mappings was very fast, on the order of a few minutes, since mesh nodes were searched in a KD tree. Distance errors in mapping mesh nodes back and forth between meshes were less than the size of an element. Analytically derived fiber directions were also mapped across meshes and compared, showing  < 5° difference over most of the ventricles. The ability to transfer gradients was also demonstrated. Topologically variable structures, like papillary muscles, required further definition outside of the UVC framework. In conclusion, UVC can aid in transferring many types of data between different biventricular geometries. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

Biomechanical properties of synthetic surgical meshes for pelvic prolapse repair.

PubMed

Todros, S; Pavan, P G; Natali, A N

2015-03-01

Synthetic meshes are widely used for surgical repair of different kind of prolapses. In the light of the experience of abdominal wall repair, similar prostheses are currently used in the pelvic region, to restore physiological anatomy after organ prolapse into the vaginal wall, that represent a recurrent dysfunction. For this purpose, synthetic meshes are surgically positioned in contact with the anterior and/or posterior vaginal wall, to inferiorly support prolapsed organs. Nonetheless, while mesh implantation restores physiological anatomy, it is often associated with different complications in the vaginal region. These potentially dangerous effects induce the surgical community to reconsider the safety and efficacy of mesh transvaginal placement. For this purpose, the evaluation of state-of-the-art research may provide the basis for a comprehensive analysis of mesh compatibility and functionality. The aim of this work is to review synthetic surgical meshes for pelvic organs prolapse repair, taking into account the mechanics of mesh material and structure, and to relate them with pelvic and vaginal tissue biomechanics. Synthetic meshes are currently available in different chemical composition, fiber and textile conformations. Material and structural properties are key factors in determining mesh biochemical and mechanical compatibility in vivo. The most significant results on vaginal tissue and surgical meshes mechanical characterization are here reported and discussed. Moreover, computational models of the pelvic region, which could support the surgeon in the evaluation of mesh performances in physiological conditions, are recalled. Copyright © 2015 Elsevier Ltd. All rights reserved.

Construction and quality assurance of large area resistive strip Micromegas for the upgrade of the ATLAS Muon Spectrometer at LHC/CERN

NASA Astrophysics Data System (ADS)

Lösel, P.

2017-06-01

Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. To cope with increasing background rates, associated with the steadily increasing luminosity of LHC to 10 times design luminosity, the present detector technology in the current innermost stations of the muon endcap system of the ATLAS experiment (the Small Wheel), will be replaced in 2019/2020 by resistive strip Micromegas and small strip TGC detectors. Both technologies will provide tracking and trigger information. In the "New Small Wheel" the Micromegas will be arranged in eight detection layers built of trapezoidally shaped quadruplets of four different sizes covering in total about 1200 m2 of detection plane. In order to achieve 15 % transverse momentum resolution for 1 TeV muons, a challenging mechanical precision is required in the construction of each active plane, with an alignment of the readout strips at the level of 30 μm RMS along the precision coordinate and 80 μm RMS perpendicular to the plane. Each individual Micromegas plane must achieve a spatial resolution better than 100 μm at background rates up to 15 kHz/cm2 while being operated in an inhomogeneous magnetic field (B <= 0.3 T). The required mechanical precision for the production of the components and their assembly, on such large area detectors, is a key point and must be controlled during construction and integration. Particularly the alignment of the readout strips within a quadruplet appears to be demanding. The readout strips are etched on PCB boards using photolithographic processes. Depending on the type of the module, 3 or 5 PCB boards need to be joined and precisely aligned to form a full readout plane. The precision in the alignment is reached either by use of precision mechanical holes or by optical masks, both referenced to the strip patterns. Assembly procedures have been developed to build the single panels with the required mechanical precision and to assemble them in a module including the four metallic micro-meshes. Methods to confirm the precision of components and assembly are based on precise optical devices and X-ray or cosmic muon investigations. We will report on the construction procedures for the Micromegas quadruplets, on the quality control procedures and results, and on the assembly and calibration methods.

An electrostatic Particle-In-Cell code on multi-block structured meshes

NASA Astrophysics Data System (ADS)

Meierbachtol, Collin S.; Svyatskiy, Daniil; Delzanno, Gian Luca; Vernon, Louis J.; Moulton, J. David

2017-12-01

We present an electrostatic Particle-In-Cell (PIC) code on multi-block, locally structured, curvilinear meshes called Curvilinear PIC (CPIC). Multi-block meshes are essential to capture complex geometries accurately and with good mesh quality, something that would not be possible with single-block structured meshes that are often used in PIC and for which CPIC was initially developed. Despite the structured nature of the individual blocks, multi-block meshes resemble unstructured meshes in a global sense and introduce several new challenges, such as the presence of discontinuities in the mesh properties and coordinate orientation changes across adjacent blocks, and polyjunction points where an arbitrary number of blocks meet. In CPIC, these challenges have been met by an approach that features: (1) a curvilinear formulation of the PIC method: each mesh block is mapped from the physical space, where the mesh is curvilinear and arbitrarily distorted, to the logical space, where the mesh is uniform and Cartesian on the unit cube; (2) a mimetic discretization of Poisson's equation suitable for multi-block meshes; and (3) a hybrid (logical-space position/physical-space velocity), asynchronous particle mover that mitigates the performance degradation created by the necessity to track particles as they move across blocks. The numerical accuracy of CPIC was verified using two standard plasma-material interaction tests, which demonstrate good agreement with the corresponding analytic solutions. Compared to PIC codes on unstructured meshes, which have also been used for their flexibility in handling complex geometries but whose performance suffers from issues associated with data locality and indirect data access patterns, PIC codes on multi-block structured meshes may offer the best compromise for capturing complex geometries while also maintaining solution accuracy and computational efficiency.

An electrostatic Particle-In-Cell code on multi-block structured meshes

DOE PAGES

Meierbachtol, Collin S.; Svyatskiy, Daniil; Delzanno, Gian Luca; ...

2017-09-14

We present an electrostatic Particle-In-Cell (PIC) code on multi-block, locally structured, curvilinear meshes called Curvilinear PIC (CPIC). Multi-block meshes are essential to capture complex geometries accurately and with good mesh quality, something that would not be possible with single-block structured meshes that are often used in PIC and for which CPIC was initially developed. In spite of the structured nature of the individual blocks, multi-block meshes resemble unstructured meshes in a global sense and introduce several new challenges, such as the presence of discontinuities in the mesh properties and coordinate orientation changes across adjacent blocks, and polyjunction points where anmore » arbitrary number of blocks meet. In CPIC, these challenges have been met by an approach that features: (1) a curvilinear formulation of the PIC method: each mesh block is mapped from the physical space, where the mesh is curvilinear and arbitrarily distorted, to the logical space, where the mesh is uniform and Cartesian on the unit cube; (2) a mimetic discretization of Poisson's equation suitable for multi-block meshes; and (3) a hybrid (logical-space position/physical-space velocity), asynchronous particle mover that mitigates the performance degradation created by the necessity to track particles as they move across blocks. The numerical accuracy of CPIC was verified using two standard plasma–material interaction tests, which demonstrate good agreement with the corresponding analytic solutions. And compared to PIC codes on unstructured meshes, which have also been used for their flexibility in handling complex geometries but whose performance suffers from issues associated with data locality and indirect data access patterns, PIC codes on multi-block structured meshes may offer the best compromise for capturing complex geometries while also maintaining solution accuracy and computational efficiency.« less

An electrostatic Particle-In-Cell code on multi-block structured meshes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meierbachtol, Collin S.; Svyatskiy, Daniil; Delzanno, Gian Luca

We present an electrostatic Particle-In-Cell (PIC) code on multi-block, locally structured, curvilinear meshes called Curvilinear PIC (CPIC). Multi-block meshes are essential to capture complex geometries accurately and with good mesh quality, something that would not be possible with single-block structured meshes that are often used in PIC and for which CPIC was initially developed. In spite of the structured nature of the individual blocks, multi-block meshes resemble unstructured meshes in a global sense and introduce several new challenges, such as the presence of discontinuities in the mesh properties and coordinate orientation changes across adjacent blocks, and polyjunction points where anmore » arbitrary number of blocks meet. In CPIC, these challenges have been met by an approach that features: (1) a curvilinear formulation of the PIC method: each mesh block is mapped from the physical space, where the mesh is curvilinear and arbitrarily distorted, to the logical space, where the mesh is uniform and Cartesian on the unit cube; (2) a mimetic discretization of Poisson's equation suitable for multi-block meshes; and (3) a hybrid (logical-space position/physical-space velocity), asynchronous particle mover that mitigates the performance degradation created by the necessity to track particles as they move across blocks. The numerical accuracy of CPIC was verified using two standard plasma–material interaction tests, which demonstrate good agreement with the corresponding analytic solutions. And compared to PIC codes on unstructured meshes, which have also been used for their flexibility in handling complex geometries but whose performance suffers from issues associated with data locality and indirect data access patterns, PIC codes on multi-block structured meshes may offer the best compromise for capturing complex geometries while also maintaining solution accuracy and computational efficiency.« less

[The ultrasound semiotics of uncomplicated wound healing after inguinal mesh plastics].

PubMed

Kharitonov, S V; Ziniakova, M V

2012-01-01

Dynamic ultrasound (US) investigation was performed in 89 patients operated on inguinal hernia with the use of meshes of various type. The US scanning proved to be a highly informative means of visualization, allowing the objective postoperative assessment of muscular and aponeurotic structures as well as the implant form and position. The study showed, that the mesh implantation was always accompanied by the exudative tissue reaction, which was determined by the physico-chemical characteristics of the implant.

Polycaprolactone electrospun mesh conjugated with an MSC affinity peptide for MSC homing in vivo.

PubMed

Shao, Zhenxing; Zhang, Xin; Pi, Yanbin; Wang, Xiaokun; Jia, Zhuqing; Zhu, Jingxian; Dai, Linghui; Chen, Wenqing; Yin, Ling; Chen, Haifeng; Zhou, Chunyan; Ao, Yingfang

2012-04-01

Mesenchymal stem cell (MSC) is a promising cell source candidate in tissue engineering (TE) and regenerative medicine. However, the inability to target MSCs in tissues of interest with high efficiency and engraftment has become a significant barrier for MSC-based therapies. The mobilization and transfer of MSCs to defective/damaged sites in tissues or organs in vivo with high efficacy and efficiency has been a major concern. In the present study, we identified a peptide sequence (E7) with seven amino acids through phage display technology, which has a high specific affinity to bone marrow-derived MSCs. Subsequent analysis suggested that the peptide could efficiently interact specifically with MSCs without any species specificity. Thereafter, E7 was covalently conjugated onto polycaprolactone (PCL) electrospun meshes to construct an "MSC-homing device" for the recruitment of MSCs both in vitro and in vivo. The E7-conjugated PCL electrospun meshes were implanted into a cartilage defect site of rat knee joints, combined with a microfracture procedure to mobilize the endogenous MSCs. After 7 d of implantation, immunofluorescence staining showed that the cells grown into the E7-conjugated PCL electrospun meshes yielded a high positive rate for specific MSC surface markers (CD44, CD90, and CD105) compared with those in arginine-glycine-aspartic acid (RGD)-conjugated PCL electrospun meshes (63.67% vs. 3.03%; 59.37% vs. 2.98%; and 61.45% vs. 3.82%, respectively). Furthermore, the percentage of CD68 positive cells in the E7-conjugated PCL electrospun meshes was much lower than that in the RGD-conjugated PCL electrospun meshes (5.57% vs. 53.43%). This result indicates that E7-conjugated PCL electrospun meshes absorb much less inflammatory cells in vivo than RGD-conjugated PCL electrospun meshes. The results of the present study suggest that the identified E7 peptide sequence has a high specific affinity to MSCs. Covalently conjugating this peptide on the synthetic PCL mesh significantly enhanced the MSC recruitment of PCL in vivo. This method provides a wide range of potential applications in TE. Copyright © 2012 Elsevier Ltd. All rights reserved.

Imaging Demonstration of a Glass Gas Electron Multiplier with Electronic Charge Readout

NASA Astrophysics Data System (ADS)

Mitsuya, Yuki; Thuiner, Patrik; Oliveri, Eraldo; Resnati, Filippo; Stenis, Miranda van; Fujiwara, Takeshi; Takahashi, Hiroyuki; Ropelewski, Leszek

2018-02-01

We have developed a Glass Gas Electron Multiplier (Glass GEM, G-GEM), which is composed of two copper electrodes separated by a photosensitive etchable glass substrate having holes arranged in a hexagonal pattern. In this paper, we report the result of imaging using a G-GEM combined with a 2D electronic charge readout. We used a crystallized photosensitive etchable glass as the G-GEM substrate. A precise X-ray image of a small mammal was successfully obtained with position resolutions of approximately 110 to 140 μm in RMS.

C2D8: An eight channel CCD readout electronics dedicated to low energy neutron detection

NASA Astrophysics Data System (ADS)

Bourrion, O.; Clement, B.; Tourres, D.; Pignol, G.; Xi, Y.; Rebreyend, D.; Nesvizhevsky, V. V.

2018-02-01

Position-sensitive detectors for cold and ultra-cold neutrons (UCN) are in use in fundamental research. In particular, measuring the properties of the quantum states of bouncing neutrons requires micro-metric spatial resolution. To this end, a Charge Coupled Device (CCD) coated with a thin conversion layer that allows a real time detection of neutron hits is under development at LPSC. In this paper, we present the design and performance of a dedicated electronic board designed to read-out eight CCDs simultaneously and operating under vacuum.

Development of a distributed read-out imaging TES X-ray microcalorimeter

NASA Astrophysics Data System (ADS)

Trowell, S.; Holland, A. D.; Fraser, G. W.; Goldie, D.; Gu, E.

2002-02-01

We report on the development of a linear absorber detector for one-dimensional imaging spectroscopy, read-out by two Transition Edge Sensors (TESs). The TESs, based on a single layer of iridium, demonstrate stable and controllable superconducting-to-normal transitions in the region of 130 mK. Results from Monte Carlo simulations are presented indicating that the device configuration is capable of detecting photon positions to better than 200 μm, thereby meeting the resolution specification for missions such as XEUS of ~250 μm. .

Scalable L-infinite coding of meshes.

PubMed

Munteanu, Adrian; Cernea, Dan C; Alecu, Alin; Cornelis, Jan; Schelkens, Peter

2010-01-01

The paper investigates the novel concept of local-error control in mesh geometry encoding. In contrast to traditional mesh-coding systems that use the mean-square error as target distortion metric, this paper proposes a new L-infinite mesh-coding approach, for which the target distortion metric is the L-infinite distortion. In this context, a novel wavelet-based L-infinite-constrained coding approach for meshes is proposed, which ensures that the maximum error between the vertex positions in the original and decoded meshes is lower than a given upper bound. Furthermore, the proposed system achieves scalability in L-infinite sense, that is, any decoding of the input stream will correspond to a perfectly predictable L-infinite distortion upper bound. An instantiation of the proposed L-infinite-coding approach is demonstrated for MESHGRID, which is a scalable 3D object encoding system, part of MPEG-4 AFX. In this context, the advantages of scalable L-infinite coding over L-2-oriented coding are experimentally demonstrated. One concludes that the proposed L-infinite mesh-coding approach guarantees an upper bound on the local error in the decoded mesh, it enables a fast real-time implementation of the rate allocation, and it preserves all the scalability features and animation capabilities of the employed scalable mesh codec.

Modelling atmospheric flows with adaptive moving meshes

NASA Astrophysics Data System (ADS)

Kühnlein, Christian; Smolarkiewicz, Piotr K.; Dörnbrack, Andreas

2012-04-01

An anelastic atmospheric flow solver has been developed that combines semi-implicit non-oscillatory forward-in-time numerics with a solution-adaptive mesh capability. A key feature of the solver is the unification of a mesh adaptation apparatus, based on moving mesh partial differential equations (PDEs), with the rigorous formulation of the governing anelastic PDEs in generalised time-dependent curvilinear coordinates. The solver development includes an enhancement of the flux-form multidimensional positive definite advection transport algorithm (MPDATA) - employed in the integration of the underlying anelastic PDEs - that ensures full compatibility with mass continuity under moving meshes. In addition, to satisfy the geometric conservation law (GCL) tensor identity under general moving meshes, a diagnostic approach is proposed based on the treatment of the GCL as an elliptic problem. The benefits of the solution-adaptive moving mesh technique for the simulation of multiscale atmospheric flows are demonstrated. The developed solver is verified for two idealised flow problems with distinct levels of complexity: passive scalar advection in a prescribed deformational flow, and the life cycle of a large-scale atmospheric baroclinic wave instability showing fine-scale phenomena of fronts and internal gravity waves.

Highly multiplexed signal readout for a time-of-flight positron emission tomography detector based on silicon photomultipliers

PubMed Central

Cates, Joshua W.; Bieniosek, Matthew F.; Levin, Craig S.

2017-01-01

Abstract. Maintaining excellent timing resolution in the generation of silicon photomultiplier (SiPM)-based time-of-flight positron emission tomography (TOF-PET) systems requires a large number of high-speed, high-bandwidth electronic channels and components. To minimize the cost and complexity of a system’s back-end architecture and data acquisition, many analog signals are often multiplexed to fewer channels using techniques that encode timing, energy, and position information. With progress in the development SiPMs having lower dark noise, after pulsing, and cross talk along with higher photodetection efficiency, a coincidence timing resolution (CTR) well below 200 ps FWHM is now easily achievable in single pixel, bench-top setups using 20-mm length, lutetium-based inorganic scintillators. However, multiplexing the output of many SiPMs to a single channel will significantly degrade CTR without appropriate signal processing. We test the performance of a PET detector readout concept that multiplexes 16 SiPMs to two channels. One channel provides timing information with fast comparators, and the second channel encodes both position and energy information in a time-over-threshold-based pulse sequence. This multiplexing readout concept was constructed with discrete components to process signals from a 4×4 array of SensL MicroFC-30035 SiPMs coupled to 2.9×2.9×20  mm3 Lu1.8Gd0.2SiO5 (LGSO):Ce (0.025 mol. %) scintillators. This readout method yielded a calibrated, global energy resolution of 15.3% FWHM at 511 keV with a CTR of 198±2  ps FWHM between the 16-pixel multiplexed detector array and a 2.9×2.9×20  mm3 LGSO-SiPM reference detector. In summary, results indicate this multiplexing scheme is a scalable readout technique that provides excellent coincidence timing performance. PMID:28382312

Are patient specific meshes required for EIT head imaging?

PubMed

Jehl, Markus; Aristovich, Kirill; Faulkner, Mayo; Holder, David

2016-06-01

Head imaging with electrical impedance tomography (EIT) is usually done with time-differential measurements, to reduce time-invariant modelling errors. Previous research suggested that more accurate head models improved image quality, but no thorough analysis has been done on the required accuracy. We propose a novel pipeline for creation of precise head meshes from magnetic resonance imaging and computed tomography scans, which was applied to four different heads. Voltages were simulated on all four heads for perturbations of different magnitude, haemorrhage and ischaemia, in five different positions and for three levels of instrumentation noise. Statistical analysis showed that reconstructions on the correct mesh were on average 25% better than on the other meshes. However, the stroke detection rates were not improved. We conclude that a generic head mesh is sufficient for monitoring patients for secondary strokes following head trauma.

A versatile localization system for microscopic multiparametric analysis of cells.

PubMed

Thaw, H H; Rundquist, I; Johansson, U; Svensson, I; Collins, V P

1983-03-01

A new, simple and relatively inexpensive electronic digital position readout (DPRO) system which can be applied to the rapid localization and recovery of microscopic material is described. It is based upon a commercially available digital position readout system which is routinely utilized by industry for small machine tools and measuring equipment. This has been mounted onto the stage of various microscopic instrumentation to provide X and Y coordinates relative to an arbitrary reference point. The integration of small computers interfaced to scanning interferometric, microdensitometric and fluorescence microscopes were used to demonstrate the reliability, versatility and ease of application of this system to problems of multiparametric measurements and analysis of cultured cells. The system may be expanded and applied to clinical material to obtain automatized, multiparametric measurements of cells in haematology and clinical cytology.

Numerical calculation of listener-specific head-related transfer functions and sound localization: Microphone model and mesh discretization

PubMed Central

Ziegelwanger, Harald; Majdak, Piotr; Kreuzer, Wolfgang

2015-01-01

Head-related transfer functions (HRTFs) can be numerically calculated by applying the boundary element method on the geometry of a listener’s head and pinnae. The calculation results are defined by geometrical, numerical, and acoustical parameters like the microphone used in acoustic measurements. The scope of this study was to estimate requirements on the size and position of the microphone model and on the discretization of the boundary geometry as triangular polygon mesh for accurate sound localization. The evaluation involved the analysis of localization errors predicted by a sagittal-plane localization model, the comparison of equivalent head radii estimated by a time-of-arrival model, and the analysis of actual localization errors obtained in a sound-localization experiment. While the average edge length (AEL) of the mesh had a negligible effect on localization performance in the lateral dimension, the localization performance in sagittal planes, however, degraded for larger AELs with the geometrical error as dominant factor. A microphone position at an arbitrary position at the entrance of the ear canal, a microphone size of 1 mm radius, and a mesh with 1 mm AEL yielded a localization performance similar to or better than observed with acoustically measured HRTFs. PMID:26233020

Mesh repair of umbilical hernia without a visible abdominal scar.

PubMed

Kurpiewski, Waldemar; Kiliańczyk, Michał; Szynkarczuk, Rafał; Tenderenda, Michał

2014-02-01

Experience in the use of Single Incision Laparoscopic Surgery procedures and the persistent urge to improve the cosmetic effect have contributed to the introduction of mesh repair of an umbilical hernia by means of a small incision in the natural position of the umbilicus. The aim of the study was to present the surgical technique and assess its postoperative results. During the period between 24.08.2011 and 01.01.2013, twenty-three umbilical hernia repair operations with the use of a polypropylene mesh by means of a small incision in the natural position of the umbilicus were performed. The synthetic material was placed in the preperitoneal space. The wound was closed and the umbilicus was reconstructed simultaneously, in order to make the scar invisible. Cutaneous stitches were not used. The average duration of the operation was 49 minutes. In one case of an obese patient with coexisting linea alba dehiscence, hernia recurrence was observed. All wounds healed without complications. The cosmetic effect was very good. Based on the presented experience mesh repair of the umbilical hernia by means of a small incision in the natural position of the umbilicus contributes essential benefits, such as a very good cosmetic effect without consecutive increasing costs, as compared to standard treatment by means of an infraumbilical incision.

Nickel nanowires mesh fabricated by ion beam irradiation-induced nanoscale welding for transparent conducting electrodes

NASA Astrophysics Data System (ADS)

Honey, S.; Ahmad, I.; Madhuku, M.; Naseem, S.; Maaza, M.; Kennedy, J. V.

2017-07-01

In this report, random nickel nanowires (Ni-NWs) meshes are fabricated by ions beam irradiation-induced nanoscale welding of NWs on intersecting positions. Ni-NWs are exposed to beam of 50 KeV Argon (Ar+) ions at various fluencies in the range ~1015 ions cm-2 to 1016 ions cm-2 at room temperature. Ni-NWs are welded due to accumulation of Ar+ ions beam irradiation-induced sputtered atoms on crossing positions. Ar+ ions irradiated Ni-NWs meshes are optically transparent and optical transparency is enhanced with increase in beam fluence of Ar+ ions. Ar+ ions beam irradiation-induced welded and optically transparent mesh is then exposed to 2.75 MeV hydrogen (H+) ions at fluencies 1  ×  1015 ions cm-2, 3  ×  1015 ions cm-2 and 1  ×  1016 ions cm-2 at room temperature. MeV H+ ions irradiation-induced local heat cause melting and fusion of NWs on intersecting points and eventually lead to reduce contact resistance between Ni-NWs. Electrical conductivity is enhanced with increase in beam fluence of H+ ions. These welded highly transparent and electrically conductive Ni-NWs meshes can be employed as transparent conducting electrodes in optoelectronic devices.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poels, Kenneth, E-mail: kenneth.poels@uzbrussel.be; Verellen, Dirk; Van de Vondel, Iwein

Purpose: Because frame rates on current clinical available electronic portal imaging devices (EPID’s) are limited to 7.5 Hz, a new commercially available PerkinElmer EPID (XRD 1642 AP19) with a maximum frame rate of 30 Hz and a new scintillator (Kyokko PI200) with improved sensitivity (light output) for megavolt (MV) irradiation was evaluated. In this work, the influence of MV pulse artifacts and pulsing artifact suppression techniques on fiducial marker and marker-less detection of a lung lesion was investigated, because target localization is an important component of uncertainty in geometrical verification of real-time tumor tracking. Methods: Visicoil™ markers with a diametermore » of 0.05 and 0.075 cm were used for MV marker tracking with a frame rate of, respectively, 7.5, 15, and 30 Hz. A 30 Hz readout of the detector was obtained by a 2 × 2 pixel binning, reducing spatial resolution. Static marker detection was conducted in function of increasing phantom thickness. Additionally, marker-less tracking was conducted and compared with the ground-truth fiducial marker motion. Performance of MV target detection was investigated by comparing the least-square sine wave fit of the detected marker positions with the predefined sine wave motion. For fiducial marker detection, a Laplacian-of-Gaussian enhancement was applied after which normalized cross correlation was used to find the most probable marker position. Marker-less detection was performed by using the scale and orientation adaptive mean shift tracking algorithm. For each MV fluoroscopy, a free running (FR-nF) (ignoring MV pulsing during readout) acquisition mode was compared with two acquisition modes intending to reduce MV pulsing artifacts, i.e., combined wavelet-FFT filtering (FR-wF) and electronic readout synchronized with respect to MV pulses. Results: A 0.05 cm Visicoil marker resulted in an unacceptable root-mean square error (RMSE) > 0.2 cm with a maximum frame rate of 30 Hz during FR-nF readout. With a 30 Hz synchronized readout (S-nF) and during 15 Hz readout (independent of readout mode), RMSE was submillimeter for a static 0.05 cm Visicoil. A dynamic 0.05 cm Visicoil was not detectable on the XRD 1642 AP19, despite a fast synchronized readout. For a 0.075 cm Visicoil, deviations of sine wave motion were submillimeter (RMSE < 0.08 cm), independent of the acquisition mode (FR, S). For marker-less tumor detection, FR-nF images resulted in RMSE > 0.3 cm, while for MV fluoroscopy in S-mode RMSE < 0.1 cm for 15 Hz and RMSE < 0.16 cm for 30 Hz. Largest consistency in target localization was experienced during 15 Hz S-nF readout. Conclusions: In general, marker contrast decreased in function of higher frame rates, which was detrimental for marker detection success. In this work, Visicoils with a thickness of 0.075 cm were showing best results for a 15 Hz frame rate, while non-MV compatible 0.05 cm Visicoil markers were not visible on the new EPID with improved sensitivity compared to EPID models based on a Kodak Lanex Fast scintillator. No noticeable influence of pulsing artifacts on the detection of a 0.075 cm Visicoil was observed, while a synchronized readout provided most reliable detection of a marker-less soft-tissue structure.« less

Prevention of parastomal herniation with biologic/composite prosthetic mesh: a systematic review and meta-analysis of randomized controlled trials.

PubMed

Wijeyekoon, Sanjaya Prabhath; Gurusamy, Kurinchi; El-Gendy, Khalid; Chan, Christopher L

2010-11-01

Parastomal herniation is a frequent complication of stoma formation and can be difficult to repair satisfactorily, making it a recognized cause of significant morbidity. A systematic review with meta-analysis of randomized clinical trials was performed to determine the benefits and risks of mesh reinforcement versus conventional stoma formation in preventing parastomal herniation. Trials were identified from The Cochrane Library trials register, Medline, Embase, Science Citation Index Expanded, and reference lists. The primary outcome was the incidence of parastomal herniation. The secondary outcomes were the incidence of parastomal herniation requiring surgical repair, postoperative morbidity, and mortality. Meta-analysis was performed using a random-effects model. The risk ratio (RR) was estimated with 95% confidence intervals (CI) based on an intention-to-treat analysis. Three trials with 129 patients were included. Composite or biologic mesh was used in either the preperitoneal or sublay position. Mesh reinforcement was associated with a reduction in parastomal herniation versus conventional stoma formation (RR 0.23, 95%CI 0.06 to 0.81; p = 0.02), and a reduction in the percentage of parastomal hernias requiring surgical treatment (RR 0.13, 95%CI 0.02 to 1.02; p = 0.05). There was no difference between groups in stoma-related morbidity (2 of 58, 3.4% in the mesh group versus 2 of 57, 3.5% in the conventional group; p = 0.97), nor was there any mortality related to the placement of mesh. Composite or biologic mesh reinforcement of stomas in the preperitoneal/sublay position is associated with a reduced incidence of parastomal herniation with no excess morbidity. Mesh reinforcement also demonstrates a trend toward a decreased incidence of parastomal herniation requiring surgical repair. Copyright © 2010 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

A novel method to calibrate DOI function of a PET detector with a dual-ended-scintillator readout.

PubMed

Shao, Yiping; Yao, Rutao; Ma, Tianyu

2008-12-01

The detection of depth-of-interaction (DOI) is a critical detector capability to improve the PET spatial resolution uniformity across the field-of-view and will significantly enhance, in particular, small bore system performance for brain, breast, and small animal imaging. One promising technique of DOI detection is to use dual-ended-scintillator readout that uses two photon sensors to detect scintillation light from both ends of a scintillator array and estimate DOI based on the ratio of signals (similar to Anger logic). This approach needs a careful DOI function calibration to establish accurate relationship between DOI and signal ratios, and to recalibrate if the detection condition is shifted due to the drift of sensor gain, bias variations, or degraded optical coupling, etc. However, the current calibration method that uses coincident events to locate interaction positions inside a single scintillator crystal has severe drawbacks, such as complicated setup, long and repetitive measurements, and being prone to errors from various possible misalignments among the source and detector components. This method is also not practically suitable to calibrate multiple DOI functions of a crystal array. To solve these problems, a new method has been developed that requires only a uniform flood source to irradiate a crystal array without the need to locate the interaction positions, and calculates DOI functions based solely on the uniform probability distribution of interactions over DOI positions without knowledge or assumption of detector responses. Simulation and experiment have been studied to validate the new method, and the results show that the new method, with a simple setup and one single measurement, can provide consistent and accurate DOI functions for the entire array of multiple scintillator crystals. This will enable an accurate, simple, and practical DOI function calibration for the PET detectors based on the design of dual-ended-scintillator readout. In addition, the new method can be generally applied to calibrating other types of detectors that use the similar dual-ended readout to acquire the radiation interaction position.

A novel method to calibrate DOI function of a PET detector with a dual-ended-scintillator readout

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shao Yiping; Yao Rutao; Ma Tianyu

The detection of depth-of-interaction (DOI) is a critical detector capability to improve the PET spatial resolution uniformity across the field-of-view and will significantly enhance, in particular, small bore system performance for brain, breast, and small animal imaging. One promising technique of DOI detection is to use dual-ended-scintillator readout that uses two photon sensors to detect scintillation light from both ends of a scintillator array and estimate DOI based on the ratio of signals (similar to Anger logic). This approach needs a careful DOI function calibration to establish accurate relationship between DOI and signal ratios, and to recalibrate if the detectionmore » condition is shifted due to the drift of sensor gain, bias variations, or degraded optical coupling, etc. However, the current calibration method that uses coincident events to locate interaction positions inside a single scintillator crystal has severe drawbacks, such as complicated setup, long and repetitive measurements, and being prone to errors from various possible misalignments among the source and detector components. This method is also not practically suitable to calibrate multiple DOI functions of a crystal array. To solve these problems, a new method has been developed that requires only a uniform flood source to irradiate a crystal array without the need to locate the interaction positions, and calculates DOI functions based solely on the uniform probability distribution of interactions over DOI positions without knowledge or assumption of detector responses. Simulation and experiment have been studied to validate the new method, and the results show that the new method, with a simple setup and one single measurement, can provide consistent and accurate DOI functions for the entire array of multiple scintillator crystals. This will enable an accurate, simple, and practical DOI function calibration for the PET detectors based on the design of dual-ended-scintillator readout. In addition, the new method can be generally applied to calibrating other types of detectors that use the similar dual-ended readout to acquire the radiation interaction position.« less

A cylindrical SPECT camera with de-centralized readout scheme

NASA Astrophysics Data System (ADS)

Habte, F.; Stenström, P.; Rillbert, A.; Bousselham, A.; Bohm, C.; Larsson, S. A.

2001-09-01

An optimized brain single photon emission computed tomograph (SPECT) camera is being designed at Stockholm University and Karolinska Hospital. The design goal is to achieve high sensitivity, high-count rate and high spatial resolution. The sensitivity is achieved by using a cylindrical crystal, which gives a closed geometry with large solid angles. A de-centralized readout scheme where only a local environment around the light excitation is readout supports high-count rates. The high resolution is achieved by using an optimized crystal configuration. A 12 mm crystal plus 12 mm light guide combination gave an intrinsic spatial resolution better than 3.5 mm (140 keV) in a prototype system. Simulations show that a modified configuration can improve this value. A cylindrical configuration with a rotating collimator significantly simplifies the mechanical design of the gantry. The data acquisition and control system uses early digitization and subsequent digital signal processing to extract timing and amplitude information, and monitors the position of the collimator. The readout system consists of 12 or more modules each based on programmable logic and a digital signal processor. The modules send data to a PC file server-reconstruction engine via a Firewire (IEEE-1394) network.

"DNA Origami Traffic Lights" with a Split Aptamer Sensor for a Bicolor Fluorescence Readout.

PubMed

Walter, Heidi-Kristin; Bauer, Jens; Steinmeyer, Jeannine; Kuzuya, Akinori; Niemeyer, Christof M; Wagenknecht, Hans-Achim

2017-04-12

A split aptamer for adenosine triphosphate (ATP) was embedded as a recognition unit into two levers of a nanomechanical DNA origami construct by extension and modification of selected staple strands. An additional optical module in the stem of the split aptamer comprised two different cyanine-styryl dyes that underwent an energy transfer from green (donor) to red (acceptor) emission if two ATP molecules were bound as target molecule to the recognition module and thereby brought the dyes in close proximity. As a result, the ATP as a target triggered the DNA origami shape transition and yielded a fluorescence color change from green to red as readout. Conventional atomic force microscopy (AFM) images confirmed the topology change from the open form of the DNA origami in the absence of ATP into the closed form in the presence of the target molecule. The obtained closed/open ratios in the absence and presence of target molecules tracked well with the fluorescence color ratios and thereby validated the bicolor fluorescence readout. The correct positioning of the split aptamer as the functional unit farthest away from the fulcrum of the DNA origami was crucial for the aptasensing by fluorescence readout. The fluorescence color change allowed additionally to follow the topology change of the DNA origami aptasensor in real time in solution. The concepts of fluorescence energy transfer for bicolor readout in a split aptamer in solution, and AFM on surfaces, were successfully combined in a single DNA origami construct to obtain a bimodal readout. These results are important for future custom DNA devices for chemical-biological and bioanalytical purposes because they are not only working as simple aptamers but are also visible by AFM on the single-molecule level.

Gas reservoir and a method to supply gas to plasma tubes

DOEpatents

Stautner, Ernst Wolfgang; Michael, Joseph Darryl

2017-01-31

A reservoir for storing and supplying a portion of a reservoir gas into a gas-filled tube is presented. The reservoir includes a first vessel having a thermally conductive surface, a meshed vessel having a lid, and placed inside the first vessel to form a cavity between the meshed vessel and the first vessel, at least one tray placed inside the meshed vessel to divide an inner space of the meshed vessel into a plurality of compartments, a sorbent material placed inside the plurality of compartments in the meshed vessel, a temperature control device positioned such that a first portion of the temperature control device is in physical contact with at least a portion of the thermally conductive surface, and a change in the temperature of the temperature control device changes the temperature of the sorbent material, wherein the reservoir gas is retained by the sorbent material at the storage temperature.

Mechanical response of the herniated human abdomen to the placement of different prostheses.

PubMed

Hernández-Gascón, Belén; Peña, Estefanía; Grasa, Jorge; Pascual, Gemma; Bellón, Juan M; Calvo, Begoña

2013-05-01

This paper describes a method designed to model the repaired herniated human abdomen just after surgery and examine its static mechanical response to the maximum intra-abdominal pressure provoked by a physiological movement (standing cough). The model is based on the real geometry of the human abdomen bearing a large incisional hernia with several anatomical structures differentiated by MRI. To analyze the outcome of hernia repair, the surgical procedure was simulated by modeling a prosthesis placed over the hernia. Three surgical meshes with different mechanical properties were considered: an isotropic heavy-weight mesh (Surgipro®), a slightly anisotropic light-weight mesh (Optilene®), and a highly anisotropic medium-weight mesh (Infinit®). Our findings confirm that anisotropic implants need to be positioned such that the most compliant axis of the mesh coincides with the craneo-caudal direction of the body.

Self-locking telescoping manipulator arm

NASA Technical Reports Server (NTRS)

Nesmith, M. F. (Inventor)

1985-01-01

A telescoping manipulator arm and pivotable finger assembly are disclosed. The telescoping arm assembly includes a generally T-shaped arm having three outwardly extending fingers guided on grooved roller guides to compensate for environmental variations. The pivotable finger assembly includes four pivoting fingers. Arcuate teeth are formed on the ends of the fingers. A rack having teeth on four sides meshes with each one of the fingers. One surface of the rack includes teeth along its entire surface which mesh with teeth of one of the fingers. The teeth at the remote end of the rack engage teeth of a gear wheel. The wheel includes a worm which meshes with a worn drive shaft of the drive motor providing a ninety degree self-locking drive for locking the fingers in a desired position. A similar drive provides a self-locking drive for positioning the telescoping arm.

Optimization-based mesh correction with volume and convexity constraints

DOE PAGES

D'Elia, Marta; Ridzal, Denis; Peterson, Kara J.; ...

2016-02-24

In this study, we consider the problem of finding a mesh such that 1) it is the closest, with respect to a suitable metric, to a given source mesh having the same connectivity, and 2) the volumes of its cells match a set of prescribed positive values that are not necessarily equal to the cell volumes in the source mesh. This volume correction problem arises in important simulation contexts, such as satisfying a discrete geometric conservation law and solving transport equations by incremental remapping or similar semi-Lagrangian transport schemes. In this paper we formulate volume correction as a constrained optimizationmore » problem in which the distance to the source mesh defines an optimization objective, while the prescribed cell volumes, mesh validity and/or cell convexity specify the constraints. We solve this problem numerically using a sequential quadratic programming (SQP) method whose performance scales with the mesh size. To achieve scalable performance we develop a specialized multigrid-based preconditioner for optimality systems that arise in the application of the SQP method to the volume correction problem. Numerical examples illustrate the importance of volume correction, and showcase the accuracy, robustness and scalability of our approach.« less

Design and Optimization of Multi-Pixel Transition-Edge Sensors for X-Ray Astronomy Applications

NASA Technical Reports Server (NTRS)

Smith, Stephen J.; Adams, Joseph S.; Bandler, Simon R.; Chervenak, James A.; Datesman, Aaron Michael; Eckart, Megan E.; Ewin, Audrey J.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline A.;

Biologic meshes are not superior to synthetic meshes in ventral hernia repair: an experimental study with long-term follow-up evaluation.

PubMed

Ditzel, M; Deerenberg, E B; Grotenhuis, N; Harlaar, J J; Monkhorst, K; Bastiaansen-Jenniskens, Y M; Jeekel, J; Lange, J F

2013-10-01

In laparoscopic incisional hernia repair, direct contact between the prosthesis and the abdominal viscera is inevitable, which may lead to an inflammatory reaction resulting in abdominal adhesion formation. This study compared five different synthetic and biologic meshes in terms of adhesion formation, shrinkage, incorporation, and histologic characteristics after a period of 30 and 90 days. In 85 rats, a mesh was positioned intraperitoneally in direct contact with the viscera. Five different meshes were implanted: Prolene (polypropylene), Parietex composite (collagen-coated polyester), Strattice (porcine dermis, non-cross-linked), Surgisis (porcine small intestine submucosa, non-cross-linked), and Permacol (porcine dermis, cross-linked). The meshes were tested in terms of adhesion formation, shrinkage, and incorporation after a period of 30 and 90 days. Additionally, collagen formation after 90 days was determined. Significantly less adhesion formation was observed with Parietex composite (5 %; interquartile range [IQR], 2-5 %) and Strattice (5 %; IQR, 4-10 %) in the long term. In contrast, organs were attached to Permacol with four of seven meshes (57 %), and adhesion coverage of Surgisis mesh was present in 66 % (IQR, 0-100 %) of the cases. After 90 days, the best incorporation was seen with the Parietex composite mesh (79 %; IQR, 61-83 %). After 90 days, major alterations in adhesion formation were seen compared with 30 days. Histologically, Strattice and Parietex composite showed a new mesothelial layer on the visceral side of the mesh. Microscopic degradation and new collagen formation were seen in the Surgisis group. Parietex composite mesh demonstrated the best long-term results compared with all the other meshes. The biologic non-cross-linked mesh, Strattice, showed little adhesion formation and moderate shrinkage but poor incorporation. Biologic meshes are promising, but varying results require a more detailed investigation and demonstrate that biologic meshes are not necessarily superior to synthetic meshes. The significant changes that take place between 30 and 90 days should lead to careful interpretation of short-term experimental results.

An efficient coding theory for a dynamic trajectory predicts non-uniform allocation of entorhinal grid cells to modules.

PubMed

Mosheiff, Noga; Agmon, Haggai; Moriel, Avraham; Burak, Yoram

2017-06-01

Grid cells in the entorhinal cortex encode the position of an animal in its environment with spatially periodic tuning curves with different periodicities. Recent experiments established that these cells are functionally organized in discrete modules with uniform grid spacing. Here we develop a theory for efficient coding of position, which takes into account the temporal statistics of the animal's motion. The theory predicts a sharp decrease of module population sizes with grid spacing, in agreement with the trend seen in the experimental data. We identify a simple scheme for readout of the grid cell code by neural circuitry, that can match in accuracy the optimal Bayesian decoder. This readout scheme requires persistence over different timescales, depending on the grid cell module. Thus, we propose that the brain may employ an efficient representation of position which takes advantage of the spatiotemporal statistics of the encoded variable, in similarity to the principles that govern early sensory processing.

An efficient coding theory for a dynamic trajectory predicts non-uniform allocation of entorhinal grid cells to modules

PubMed Central

Mosheiff, Noga; Agmon, Haggai; Moriel, Avraham

2017-01-01

Grid cells in the entorhinal cortex encode the position of an animal in its environment with spatially periodic tuning curves with different periodicities. Recent experiments established that these cells are functionally organized in discrete modules with uniform grid spacing. Here we develop a theory for efficient coding of position, which takes into account the temporal statistics of the animal’s motion. The theory predicts a sharp decrease of module population sizes with grid spacing, in agreement with the trend seen in the experimental data. We identify a simple scheme for readout of the grid cell code by neural circuitry, that can match in accuracy the optimal Bayesian decoder. This readout scheme requires persistence over different timescales, depending on the grid cell module. Thus, we propose that the brain may employ an efficient representation of position which takes advantage of the spatiotemporal statistics of the encoded variable, in similarity to the principles that govern early sensory processing. PMID:28628647

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Aiwu; Hohlmann, Marcus; Azmoun, Babak

Here, we study the position sensitivity of radial zigzag strips intended to read out large GEM detectors for tracking at future experiments. Zigzag strips can cover a readout area with fewer strips than regular straight strips while maintaining good spatial resolution. Consequently, they can reduce the number of required electronic channels and related cost for large-area GEM detector systems. A non-linear relation between incident particle position and hit position measured from charge sharing among zigzag strips was observed in a previous study. We significantly reduce this non-linearity by improving the interleaving of adjacent physical zigzag strips. Zigzag readout structures aremore » implemented on PCBs and on a flexible foil and are tested using a 10 cm × 10 cm triple-GEM detector scanned with a strongly collimated X-ray gun on a 2D motorized stage. Lastly, angular resolutions of 60–84 μrad are achieved with a 1.37 mrad angular strip pitch at a radius of 784 mm. On a linear scale this corresponds to resolutions below 100 μm.« less

Prevention of parastomal hernia with a preperitoneal polypropelene mesh.

PubMed

Valdés-Hernández, Javier; Díaz Milanés, Juan Antonio; Capitán Morales, Luis Cristóbal; Del Río la Fuente, Francisco Javier; Torres Arcos, Cristina; Cañete Gómez, Jesús; Oliva Mompeán, Fernando; Padillo Ruiz, Javier

2015-01-01

To show our results with the use of a polypropylene mesh at the stoma site, as prophylaxis of parastomal hernias in patients with rectal cancer when a terminal colostomy is performed. From January 2010 until March 2014, 45 consecutive patients with rectal cancer, underwent surgical treatment with the need of a terminal colostomy. A prophylactic mesh was placed in a sublay position at the stoma site in all cases. We analyze Demographics, technical issues and effectiveness of the procedure, as well as subsequent complications. A prophylactic mesh was placed in 45 patients, 35 male and 10 females, mean age of 66.2 (47-88) and Body Mass Index 29.19 (20.4-40.6). A total of 7 middle rectal carcinoma, 36 low rectal carcinoma, one rectal melanoma and one squamous cell anal carcinoma were electively treated with identical protocol. Abdominoperineal resection was performed in 38 patients, and low anterior resection with terminal colostomy in 7. An open approach was elected in 39 patients and laparoscopy in 6, with 2 conversions to open surgery. Medium follow up was 22 months (2.1-53). Overall, 3 parastomal hernias (6.66%) were found, one of which was a radiological finding with no clinical significance. No complications related to the mesh or the colostomy were found. The use of a prophylactic polypropylene mesh placed in a sublay position at the stoma site is a safe and feasible technique. It lowers the incidence of parastomal hernias with no increased morbidity. Copyright © 2014 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

Prevention of parastomal hernias with 3D funnel meshes in intraperitoneal onlay position by placement during initial stoma formation.

PubMed

Köhler, G; Hofmann, A; Lechner, M; Mayer, F; Wundsam, H; Emmanuel, K; Fortelny, R H

2016-02-01

In patients with terminal ostomies, parastomal hernias (PSHs) occur on a frequent basis. They are commonly associated with various degrees of complaints and occasionally lead to life-threatening complications. Various strategies and measures have been tested and evaluated, but to date there is a lack of published evidence with regard to the best surgical technique for the prevention of PSH development. We conducted a retrospective analysis of prospectively collected data of eighty patients, who underwent elective permanent ostomy formation between 2009 and 2014 by means of prophylactic implantation of a three-dimensional (3D) funnel mesh in intraperitoneal onlay (IPOM) position. PSH developed in three patients (3.75%). No mesh-related complications were encountered and none of the implants had to be removed. Ostomy-related complications had to be noted in seven (8.75%) cases. No manifestation of ostomy prolapse occurred. Follow-up time was a median 21 (range 3-47) months. The prophylactical implantation of a specially shaped, 3D mesh implant in IPOM technique during initial formation of a terminal enterostomy is safe, highly efficient and comparatively easy to perform. As opposed to what can be achieved with flat or keyhole meshes, the inner boundary areas of the ostomy itself can be well covered and protected from the surging viscera with the 3D implants. At the same time, the vertical, tunnel-shaped part of the mesh provides sufficient protection from an ostomy prolapse. Further studies will be needed to compare the efficacy of various known approaches to PSH prevention.

Automatic readout micrometer

DOEpatents

Lauritzen, Ted

1982-01-01

A measuring system is disclosed for surveying and very accurately positioning objects with respect to a reference line. A principal use of this surveying system is for accurately aligning the electromagnets which direct a particle beam emitted from a particle accelerator. Prior art surveying systems require highly skilled surveyors. Prior art systems include, for example, optical surveying systems which are susceptible to operator reading errors, and celestial navigation-type surveying systems, with their inherent complexities. The present invention provides an automatic readout micrometer which can very accurately measure distances. The invention has a simplicity of operation which practically eliminates the possibilities of operator optical reading error, owning to the elimination of traditional optical alignments for making measurements. The invention has an extendable arm which carries a laser surveying target. The extendable arm can be continuously positioned over its entire length of travel by either a coarse or fine adjustment without having the fine adjustment outrun the coarse adjustment until a reference laser beam is centered on the target as indicated by a digital readout. The length of the micrometer can then be accurately and automatically read by a computer and compared with a standardized set of alignment measurements. Due to its construction, the micrometer eliminates any errors due to temperature changes when the system is operated within a standard operating temperature range.

Automatic readout micrometer

DOEpatents

Lauritzen, T.

A measuring system is described for surveying and very accurately positioning objects with respect to a reference line. A principle use of this surveying system is for accurately aligning the electromagnets which direct a particle beam emitted from a particle accelerator. Prior art surveying systems require highly skilled surveyors. Prior art systems include, for example, optical surveying systems which are susceptible to operator reading errors, and celestial navigation-type surveying systems, with their inherent complexities. The present invention provides an automatic readout micrometer which can very accurately measure distances. The invention has a simplicity of operation which practically eliminates the possibilities of operator optical reading error, owning to the elimination of traditional optical alignments for making measurements. The invention has an extendable arm which carries a laser surveying target. The extendable arm can be continuously positioned over its entire length of travel by either a coarse of fine adjustment without having the fine adjustment outrun the coarse adjustment until a reference laser beam is centered on the target as indicated by a digital readout. The length of the micrometer can then be accurately and automatically read by a computer and compared with a standardized set of alignment measurements. Due to its construction, the micrometer eliminates any errors due to temperature changes when the system is operated within a standard operating temperature range.

Full-Carpet Design of a Low-Boom Demonstrator Concept

NASA Technical Reports Server (NTRS)

Ordaz, Irian; Wintzer, Mathias; Rallabhandi, Sriram K.

2015-01-01

The Cart3D adjoint-based design framework is used to mitigate the undesirable o -track sonic boom properties of a demonstrator concept designed for low-boom directly under the flight path. First, the requirements of a Cart3D design mesh are determined using a high-fidelity mesh adapted to minimize the discretization error of the CFD analysis. Low-boom equivalent area targets are then generated at the under-track and one off-track azimuthal position for the baseline configuration. The under-track target is generated using a trim- feasible low-boom target generation process, ensuring that the final design is not only low-boom, but also trimmed at the specified flight condition. The o -track equivalent area target is generated by minimizing the A-weighted loudness using an efficient adjoint-based approach. The configuration outer mold line is then parameterized and optimized to match the off-body pressure distributions prescribed by the low-boom targets. The numerical optimizer uses design gradients which are calculated using the Cart3D adjoint- based design capability. Optimization constraints are placed on the geometry to satisfy structural feasibility. The low-boom properties of the final design are verified using the adaptive meshing approach. This analysis quantifies the error associated with the CFD mesh that is used for design. Finally, an alternate mesh construction and target positioning approach offering greater computational efficiency is demonstrated and verified.

Transvaginal single-incision mesh reconstruction for recurrent or advanced anterior vaginal wall prolapse.

PubMed

Marschke, J; Hengst, L; Schwertner-Tiepelmann, N; Beilecke, K; Tunn, R

2015-05-01

Single-incision transvaginal mesh for reconstruction of Level I and II prolapses in women with recurrent or advanced prolapse. We evaluated functional, anatomical, sonomorphological and quality-of-life outcome. Data were collected retrospectively for preoperative parameters and at follow-up visits. Anatomical cure was assessed with vaginal examination using the ICS-POP-Q system; introital-ultrasound scan for postvoidal residual and description of mesh characteristics was performed. We applied a visual analogue scale (VAS) and the German Pelvic Floor Questionnaire to assess quality-of-life. Seventy women with cystocele (III: 61.3%/IV: 16%), all post-hysterectomy and in majority (81.4%) after previous cystocele repair, were operated using a single-incision transvaginal technique. Overall anatomical success rate was 95.7% with significant improvement in quality-of-life (p < 0.0001). Mesh erosion occurred in 5.7%, one patient presented symptomatic vaginal vault prolapse. Postvoidal residual declined significantly (58 vs. 2.9%). Sonographic mesh length was 55.7% of implanted mesh with a wide range of mesh position, but no signs of mesh dislocation. There was no de novo dyspareunia reported, one case of preoperative existing dyspareunia worsened. No severe adverse event was observed. We hereby present a trial of a high-risk group of patients requiring reconstruction of anterior and apical vaginal wall in mostly recurrent prolapse situation. Our data support the hypothesis of improved anatomical and functional results and less mesh shrinkage caused by the single-incision technique with fixation in sacrospinous ligament in combination with modification in mesh quality compared to former multi-incision techniques.

Unitary Shaft-Angle and Shaft-Speed Sensor Assemblies

NASA Technical Reports Server (NTRS)

Alhorn, Dean C.; Howard, David E.; Smith, Dennis A.

2006-01-01

The figure depicts a unit that contains a rotary-position or a rotary-speed sensor, plus electronic circuitry necessary for its operation, all enclosed in a single housing with a shaft for coupling to an external rotary machine. This rotation sensor unit is complete: when its shaft is mechanically connected to that of the rotary machine and it is supplied with electric power, it generates an output signal directly indicative of the rotary position or speed, without need for additional processing by other circuitry. The incorporation of all of the necessary excitatory and readout circuitry into the housing (in contradistinction to using externally located excitatory and/or readout circuitry) in a compact arrangement is the major difference between this unit and prior rotation-sensor units. The sensor assembly inside the housing includes excitatory and readout integrated circuits mounted on a circular printed-circuit board. In a typical case in which the angle or speed transducer(s) utilize electromagnetic induction, the assembly also includes another circular printed-circuit board on which the transducer windings are mounted. A sheet of high-magnetic permeability metal ("mu metal") is placed between the winding board and the electronic-circuit board to prevent spurious coupling of excitatory signals from the transducer windings to the readout circuits. The housing and most of the other mechanical hardware can be common to a variety of different sensor designs. Hence, the unit can be configured to generate any of variety of outputs by changing the interior sensor assembly. For example, the sensor assembly could contain an analog tachometer circuit that generates an output proportional (in both magnitude and sign or in magnitude only) to the speed of rotation.

Method for making an elastomeric member with end pieces

DOEpatents

Hoppie, L.O.; McNinch, J.H. Jr.; Nowell, G.C.

1984-10-23

A molding process is described for molding an elongated elastomeric member with wire mesh sleeves bonded to the ends. A molding preform of elastomeric material is positioned within a seamless mold cylinder, and the open ends of the wire mesh sleeves are mounted to end plug assemblies slidably received into the mold cylinder and positioned against the ends of the preform. A specialized profile is formed into surfaces of the respective end plug assemblies and by heating of the mold, the ends of the elastomeric preform are molded to the profile, as well as bonded to the reinforcing wire mesh sleeves. Vacuum is applied to the interior of the mold to draw outgassing vapors through relief spaces there through. The completed elastomeric member is removed from the mold cylinder by stretching, the consequent reduction in diameter enabling ready separation from the mold cylinder and removal thereof. 9 figs.

Front tracking based modeling of the solid grain growth on the adaptive control volume grid

NASA Astrophysics Data System (ADS)

Seredyński, Mirosław; Łapka, Piotr

2017-07-01

The paper presents the micro-scale model of unconstrained solidification of the grain immersed in under-cooled liquid, based on the front tracking approach. For this length scale, the interface tracked through the domain is meant as the solid-liquid boundary. To prevent generation of huge meshes the energy transport equation is discretized on the adaptive control volume (c.v.) mesh. The coupling of dynamically changing mesh and moving front position is addressed. Preliminary results of simulation of a test case, the growth of single grain, are presented and discussed.

Nonlinear Dynamics and Strong Cavity Cooling of Levitated Nanoparticles.

PubMed

Fonseca, P Z G; Aranas, E B; Millen, J; Monteiro, T S; Barker, P F

2016-10-21

Optomechanical systems explore and exploit the coupling between light and the mechanical motion of macroscopic matter. A nonlinear coupling offers rich new physics, in both quantum and classical regimes. We investigate a dynamic, as opposed to the usually studied static, nonlinear optomechanical system, comprising a nanosphere levitated in a hybrid electro-optical trap. The cavity offers readout of both linear-in-position and quadratic-in-position (nonlinear) light-matter coupling, while simultaneously cooling the nanosphere, for indefinite periods of time and in high vacuum. We observe the cooling dynamics via both linear and nonlinear coupling. As the background gas pressure was lowered, we observed a greater than 1000-fold reduction in temperature before temperatures fell below readout sensitivity in the present setup. This Letter opens the way to strongly coupled quantum dynamics between a cavity and a nanoparticle largely decoupled from its environment.

Nonlinear Dynamics and Strong Cavity Cooling of Levitated Nanoparticles

NASA Astrophysics Data System (ADS)

Fonseca, P. Z. G.; Aranas, E. B.; Millen, J.; Monteiro, T. S.; Barker, P. F.

2016-10-01

Optomechanical systems explore and exploit the coupling between light and the mechanical motion of macroscopic matter. A nonlinear coupling offers rich new physics, in both quantum and classical regimes. We investigate a dynamic, as opposed to the usually studied static, nonlinear optomechanical system, comprising a nanosphere levitated in a hybrid electro-optical trap. The cavity offers readout of both linear-in-position and quadratic-in-position (nonlinear) light-matter coupling, while simultaneously cooling the nanosphere, for indefinite periods of time and in high vacuum. We observe the cooling dynamics via both linear and nonlinear coupling. As the background gas pressure was lowered, we observed a greater than 1000-fold reduction in temperature before temperatures fell below readout sensitivity in the present setup. This Letter opens the way to strongly coupled quantum dynamics between a cavity and a nanoparticle largely decoupled from its environment.

Probing the limits to positional information

PubMed Central

Gregor, Thomas; Tank, David W.; Wieschaus, Eric F.; Bialek, William

2008-01-01

The reproducibility and precision of biological patterning is limited by the accuracy with which concentration profiles of morphogen molecules can be established and read out by their targets. We consider four measures of precision for the Bicoid morphogen in the Drosophila embryo: The concentration differences that distinguish neighboring cells, the limits set by the random arrival of Bicoid molecules at their targets (which depends on absolute concentration), the noise in readout of Bicoid by the activation of Hunchback, and the reproducibility of Bicoid concentration at corresponding positions in multiple embryos. We show, through a combination of different experiments, that all of these quantities are ~10%. This agreement among different measures of accuracy indicates that the embryo is not faced with noisy input signals and readout mechanisms; rather the system exerts precise control over absolute concentrations and responds reliably to small concentration differences, approaching the limits set by basic physical principles. PMID:17632062

An asynchronous data-driven readout prototype for CEPC vertex detector

NASA Astrophysics Data System (ADS)

Yang, Ping; Sun, Xiangming; Huang, Guangming; Xiao, Le; Gao, Chaosong; Huang, Xing; Zhou, Wei; Ren, Weiping; Li, Yashu; Liu, Jianchao; You, Bihui; Zhang, Li

2017-12-01

The Circular Electron Positron Collider (CEPC) is proposed as a Higgs boson and/or Z boson factory for high-precision measurements on the Higgs boson. The precision of secondary vertex impact parameter plays an important role in such measurements which typically rely on flavor-tagging. Thus silicon CMOS Pixel Sensors (CPS) are the most promising technology candidate for a CEPC vertex detector, which can most likely feature a high position resolution, a low power consumption and a fast readout simultaneously. For the R&D of the CEPC vertex detector, we have developed a prototype MIC4 in the Towerjazz 180 nm CMOS Image Sensor (CIS) process. We have proposed and implemented a new architecture of asynchronous zero-suppression data-driven readout inside the matrix combined with a binary front-end inside the pixel. The matrix contains 128 rows and 64 columns with a small pixel pitch of 25 μm. The readout architecture has implemented the traditional OR-gate chain inside a super pixel combined with a priority arbiter tree between the super pixels, only reading out relevant pixels. The MIC4 architecture will be introduced in more detail in this paper. It will be taped out in May and will be characterized when the chip comes back.

Comparison between various densities of pore titanium meshes and e-polytetrafluoroethylene (ePTFE) membrane regarding bone regeneration induced by low intensity pulsed ultrasound (LIPUS) in rabbit nasal bone.

PubMed

Higuchi, Masatoshi; Moroi, Akinori; Yoshizawa, Kunio; Kosaka, Akihiko; Ikawa, Hiroumi; Iguchi, Ran; Saida, Yuriko; Hotta, Asami; Tsutsui, Takamitsu; Ueki, Koichiro

2016-09-01

The purpose of this study was to compare bone regenerative capability following use of polytetrafluoroethylene (ePTFE) membrane against that when various densities of pore titanium meshes are used with and without low intensity pulsed ultrasound (LIPUS). Adult male white rabbits were divided into 8 groups. In 4 groups, after incising along the nasal bone, four 3 × 8 mm bone defects were made in both sides and covered by an ePTFE membrane (group E: n = 15), a high density pore titanium mesh (group H: n = 15), a low density pore titanium mesh (group L: n = 15), and no mesh (control) (group C: n = 15). Furthermore, LIPUS was irradiated after surgery in 4 groups (groups EL, HL, LL and CL, in each n = 15). The rabbits were sacrificed at 1, 2 and 8 weeks postoperative, and formalin-fixed specimens were embedded in acrylic resin. The specimens were stained with hematoxylin and eosin. For immunohistochemical analysis, the specimens were treated with bone morphogenetic protein (BMP)-2 antibody. Group H had significantly higher values than groups L, E, and C regarding bone area ratio and labeling index of BMP-2 positive cells (P < 0.05). Furthermore, Group HL also had significantly higher values than the other groups regarding bone area ratio and labeling index of BMP-2 positive cells at 1, 2 and 8 weeks postoperative (P < 0.05). The results suggested that high density pore titanium mesh could induce new bone regeneration more than low density pore titanium mesh and ePTFE membrane. New bone formation may increase following LIPUS application. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Practical Considerations for Optimizing Position Sensitivity in Arrays of Position-sensitive TES's

NASA Technical Reports Server (NTRS)

Smith, Stephen J.; Bandler, Simon R.; Figueroa-Feliciano, Encetali; Iyomoto, Naoko; Kelley, Richard L.; Kilbourne, Caroline A.; Porder, Frederick S.; Sadleir, John E.

2007-01-01

We are developing Position-Sensitive Transitions-Edge Sensors (PoST's) for future X-ray astronomy missions such as NASA's Constellation-X. The PoST consists of one or more Transitions Edge Sensors (TES's) thermally connected to a large X-ray absorber, which through heat diffusion, gives rise to position dependence. The development of PoST's is motivated by the desire to achieve the largest the focal-plan coverage with the fewest number of readout channels. In order to develop a practical array, consisting of an inner pixellated core with an outer array of large absorber PoST's, we must be able to simultaneously read out all (-1800) channels in the array. This is achievable using time division multiplexing (TDM), but does set stringent slew rate requirements on the array. Typically, we must damp the pulses to reduce the slew rate of the input signal to the TDM. This is achieved by applying a low-pass analog filter with large inductance to the signal. This attenuates the high frequency components of the signal, essential for position discrimination in PoST's, relative to the white noise of the readout chain and degrades the position sensitivity. Using numerically simulated data, we investigate the position sensing ability of typical PoST designs under such high inductance conditions. We investigate signal-processing techniques for optimal determination of the event position and discuss the practical considerations for real-time implementation.

Sub-micron accurate track navigation method ``Navi'' for the analysis of Nuclear Emulsion

NASA Astrophysics Data System (ADS)

Yoshioka, T.; Yoshida, J.; Kodama, K.

2011-03-01

Sub-micron accurate track navigation in Nuclear Emulsion is realized by using low energy signals detected by automated Nuclear Emulsion read-out systems. Using those much dense ``noise'', about 104 times larger than the real tracks, the accuracy of the track position navigation reaches to be sub micron only by using the information of a microscope field of view, 200 micron times 200 micron. This method is applied to OPERA analysis in Japan, i.e. support of human eye checks of the candidate tracks, confirmation of neutrino interaction vertexes and to embed missing track segments to the track data read-out by automated systems.

Effects of polyglactin mesh combined with resorbable calcium carbonate or replamineform hydroxyapatite on periodontal repair in dogs.

PubMed

Moon, I S; Chai, J K; Cho, K S; Wikesjö, U M; Kim, C K

1996-10-01

This study evaluates periodontal repair and biomaterial reaction following implantation of a polyglactin mesh with or without porous resorbable calcium carbonate (RCC) or porous replamineform hydroxyapatite (RHA) in conjunction with reconstructive surgery. Ligature- and surgically-induced interproximal periodontal defects of left and right mandibular premolar teeth in 7 dogs were used. Bilaterally, mesial defects of the 2nd, 3rd and 4th premolar teeth were treated with polyglactin mesh, polyglactin mesh and RHA, or polyglactin mesh and RCC, respectively. The polyglactin mesh, shaped according to the contour of the defect, was adapted to the experimental teeth; its coronal margin positioned immediately apical to the cemento-enamel junction. Gingival flap margins were adapted and sutured to cover the polyglactin mesh completely. Clinical healing was generally uneventful. The dogs were sacrificed to provide block sections for histologic evaluation at 1, 3, 6, 12, 26, 32 and 56 weeks following wound closure. Generally, cementum regeneration was observed beginning at week 6 in all groups. Bone regeneration was observed from week 3 in polyglactin mesh-treated groups, and from week 6 in polyglactin mesh+RCC or polyglactin mesh+RHA treated groups. Bone regeneration appeared enhanced in polyglactin mesh+RCC or polyglactin mesh+RHA treated defects at week 12 and 26, with little difference between the three experimental conditions at week 56. Polyglactin mesh degradation was observed at week 3 and appeared complete at week 12. The RHA did not appear to resorb, while the RCC was gradually replaced by bone from week 3. Within limitations of the study conditions, periodontal regeneration was observed following implantation of a polyglactin mesh with or without RCC or RHA in conjunction with reconstructive surgery. As a conclusion, there seems to be no significant difference in periodontal regeneration after 12 months of healing between the group treated with the membrane only, and the group treated with the membrane and the bone substitution material. Changes in connective fiber orientation over the 1st 12 weeks of healing may suggest that "fibrous encapsulation" observed in earlier studies may only represent a transient stage in periodontal regeneration.

Development of 3He LPSDs and read-out system for the SANS spectrometer at CPHS

NASA Astrophysics Data System (ADS)

Huang, T. C.; Gong, H.; Shao, B. B.; Wang, X. W.; Zhang, Y.; Pang, B. B.

2014-01-01

The Compact Pulsed Hadron Source (CPHS) is a 13-MeV proton-linac-driven neutron source under construction in Tsinghua University. Time-of-flight (TOF) small-angle neutron scattering (SANS) spectrometer is one of the first instruments to be built. It is designed to use linear position-sensitive detectors (LPSDs) of 3He gas proportional counters to cover a 1 m×1 m area. Prototypical LPSDs (Φ = 12 mm, L=1 m) have been made and read-out system is developed based on charge division. This work describes the in-house fabrication of the prototypical LPSDs and design of the read-out system including front-end electronics and data acquisition (DAQ) system. Key factors of the front-end electronics are studied and optimized with PSPICE simulation. DAQ system is designed based on VME bus architecture and FPGA Mezzanine Card (FMC) standard with high flexibility and extendibility. Preliminary experiments are carried out and the results are present and discussed.

Evaluation of rapid readout biological indicators for 132 degrees C gravity and 132 degrees C vacuum-assisted steam sterilization cycles using a new automated fluorescent reader.

PubMed

Alfa, Michelle J; Olson, Nancy; DeGagne, Pat; Jackson, Michele

2002-07-01

The primary objective of this study was to evaluate fluorescent readout results of Attest 1291 Biological Indicators (BIs) (3M Health Care, St. Paul, MN) and Attest 1296 BI test packs (containing Attest 1292 BIs) using full and fractional cycles compared with the growth data when prolonged incubation (7 days) was included. Gravity displacement and vacuum-assisted steam sterilization cycles were evaluated. A secondary objective of this study was to evaluate the new automated rapid fluorescent reader (Attest 290 Auto Reader). The rapid readout BIs for gravity displacement and vacuum-assisted steam autoclave cycles at 132 degrees C were processed using full (4 minutes) and four fractional cycles that provided 30% to 80% positive results for growth after 24 hours of incubation (48 hours of incubation for Attest 1292 BIs from the Attest 1296 test packs). Sixty of each type of BI were tested for each cycle (300 of each BI type in total). For all full steam sterilization cycles, results of the rapid fluorescent readout and the 24-hour, 48-hour, and 7-day growth tests were negative for all Attest 1291 and 1292 BIs tested. For all fractional cycles, the 24- and 48-hour growth results for the Attest 1291 and 1292 BIs, respectively, were the same as the 7-day growth results. The fractional cycle data indicated that fluorescent rapid readout was a more sensitive indicator than growth. There were rare (0.9%) false-negative results for BIs under fractional cycle conditions and these all correlated with short fractional cycle exposure times. The fluorescent rapid readout results of the 1291 BIs and 1296 BI test packs reliably predict both 24- and 48-hour and 7-day growth. These data support the value of rapid readout BIs for sterilizer monitoring for both the vacuum-assisted and the gravity displacement steam sterilization cycles. The new automated reader requires less manipulation of the BI and makes monitoring user friendly and less prone to user errors.

A custom readout electronics for the BESIII CGEM detector

NASA Astrophysics Data System (ADS)

Da Rocha Rolo, M.; Alexeev, M.; Amoroso, A.; Baldini Ferroli, R.; Bertani, M.; Bettoni, D.; Bianchi, F.; Bugalho, R.; Calcaterra, A.; Canale, N.; Capodiferro, M.; Carassiti, V.; Cerioni, S.; Chai, J. Y.; Chiozzi, S.; Cibinetto, G.; Cossio, F.; Cotta Ramusino, A.; De Mori, F.; Destefanis, M.; Di Francesco, A.; Dong, J.; Evangelisti, F.; Farinelli, R.; Fava, L.; Felici, G.; Fioravanti, E.; Garzia, I.; Gatta, M.; Greco, M.; Lavezzi, L.; Leng, C. Y.; Li, H.; Maggiora, M.; Malaguti, R.; Marcello, S.; Marciniewski, P.; Melchiorri, M.; Mezzadri, G.; Mignone, M.; Morello, G.; Pacetti, S.; Patteri, P.; Pellegrino, J.; Pelosi, A.; Rivetti, A.; Savrié, M.; Scodeggio, M.; Soldani, E.; Sosio, S.; Spataro, S.; Tskhadadze, E.; Varela, J.; Verma, S.; Wheadon, R.; Yan, L.

2017-07-01

For the upgrade of the inner tracker of the BESIII spectrometer, planned for 2018, a lightweight tracker based on an innovative Cylindrical Gas Electron Multiplier (CGEM) detector is now under development. The analogue readout of the CGEM enables the use of a charge centroid algorithm to improve the spatial resolution to better than 130 μm while loosening the pitch strip to 650 μm, which allows to reduce the total number of channels to about 10 000. The channels are readout by 160 dedicated integrated 64-channel front-end ASICs, providing a time and charge measurement and featuring a fully-digital output. The energy measurement is extracted either from the time-over-threshold (ToT) or the 10-bit digitisation of the peak amplitude of the signal. The time of the event is generated by quad-buffered low-power TDCs, allowing for rates in excess of 60 kHz per channel. The TDCs are based on analogue interpolation techniques and produce a time stamp (or two, if working in ToT mode) of the event with a time resolution better than 50 ps. The front-end noise, based on a CSA and a two-stage complex conjugated pole shapers, dominate the channel intrinsic time jitter, which is less than 5 ns r.m.s. The time information of the hit can be used to reconstruct the track path, operating the detector as a small TPC and hence improving the position resolution when the distribution of the cloud, due to large incident angle or magnetic field, is very broad. Event data is collected by an off-detector motherboard, where each GEM-ROC readout card handles 4 ASIC carrier FEBs (512 channels). Configuration upload and data readout between the off-detector electronics and the VME-based data collector cards are managed by bi-directional fibre optical links. This paper covers the design of a custom front-end electronics for the readout of the new inner tracker of the BESIII experiment, addressing the relevant design aspects of the detector electronics and the front-end ASIC for the CGEM readout, and reviewing the first silicon results of the chip prototype.

Reusable conductimetric array of interdigitated microelectrodes for the readout of low-density microarrays.

PubMed

Mallén, Maria; Díaz-González, María; Bonilla, Diana; Salvador, Juan P; Marco, María P; Baldi, Antoni; Fernández-Sánchez, César

2014-06-17

Low-density protein microarrays are emerging tools in diagnostics whose deployment could be primarily limited by the cost of fluorescence detection schemes. This paper describes an electrical readout system of microarrays comprising an array of gold interdigitated microelectrodes and an array of polydimethylsiloxane microwells, which enabled multiplexed detection of up to thirty six biological events on the same substrate. Similarly to fluorescent readout counterparts, the microarray can be developed on disposable glass slide substrates. However, unlike them, the presented approach is compact and requires a simple and inexpensive instrumentation. The system makes use of urease labeled affinity reagents for developing the microarrays and is based on detection of conductivity changes taking place when ionic species are generated in solution due to the catalytic hydrolysis of urea. The use of a polydimethylsiloxane microwell array facilitates the positioning of the measurement solution on every spot of the microarray. Also, it ensures the liquid tightness and isolation from the surrounding ones during the microarray readout process, thereby avoiding evaporation and chemical cross-talk effects that were shown to affect the sensitivity and reliability of the system. The performance of the system is demonstrated by carrying out the readout of a microarray for boldenone anabolic androgenic steroid hormone. Analytical results are comparable to those obtained by fluorescent scanner detection approaches. The estimated detection limit is 4.0 ng mL(-1), this being below the threshold value set by the World Anti-Doping Agency and the European Community. Copyright © 2014 Elsevier B.V. All rights reserved.

Zero suppression logic of the ALICE muon forward tracker pixel chip prototype PIXAM and associated readout electronics development

NASA Astrophysics Data System (ADS)

Flouzat, C.; Değerli, Y.; Guilloux, F.; Orsini, F.; Venault, P.

2015-05-01

In the framework of the ALICE experiment upgrade at HL-LHC, a new forward tracking detector, the Muon Forward Tracker (MFT), is foreseen to overcome the intrinsic limitations of the present Muon Spectrometer and will perform new measurements of general interest for the whole ALICE physics. To fulfill the new detector requirements, CMOS Monolithic Active Pixel Sensors (MAPS) provide an attractive trade-off between readout speed, spatial resolution, radiation hardness, granularity, power consumption and material budget. This technology has been chosen to equip the Muon Forward Tracker and also the vertex detector: the Inner Tracking System (ITS). Since few years, an intensive R&D program has been performed on the design of MAPS in the 0.18 μ m CMOS Image Sensor (CIS) process. In order to avoid pile up effects in the experiment, the classical rolling shutter readout system of MAPS has been improved to overcome the readout speed limitation. A zero suppression algorithm, based on a 3 by 3 cluster finding (position and data), has been chosen for the MFT. This algorithm allows adequate data compression for the sensor. This paper presents the large size prototype PIXAM, which represents 1/3 of the final chip, and will focus specially on the zero suppression block architecture. This chip is designed and under fabrication in the 0.18 μ m CIS process. Finally, the readout electronics principle to send out the compressed data flow is also presented taking into account the cluster occupancy per MFT plane for a single central Pb-Pb collision.

Extended focal-plane array development for the International X-ray Observatory

NASA Astrophysics Data System (ADS)

Smith, Stephen J.; Bandler, Simon R.; Beyer, Joern; Chervenak, James A.; Drung, Dietmar; Eckart, Megan E.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline A.; Scott Porter, F.; Sadleir, John E.

2009-12-01

We are developing arrays of transition-edge sensors (TES's) for the International X-ray observatory (IXO). The IXO microcalorimeter array will consist of a central 40×40 core of 300 μm pitch pixels with a resolution of 2.5 eV from 0.3-10 keV. To maximize the science return from the mission, an outer extended array is also required. This 52×52 array (2304 elements surrounding the core) of 600 μm pitch pixels increases the field-of-view from 2' to 5.4' with a resolution of 10 eV. However, significantly increasing the number of readout channels is unfavorable due to the increase in mass and power of the readout chain as well as adding complexity at the focal plane. Consequently, we are developing position-sensitive devices which maintain the same plate scale but at a reduced number of readout channels. One option is to use multiple absorber elements with different thermal conductances to a single TES. Position discrimination is achieved from differences in the pulse rise-time. Another new option is to inductively couple several TES's to a single SQUID. Position discrimination can be achieved by using different combinations of coupling polarity, inductive couplings and heat sink conductances. We present first results demonstrating <9 eV across four 500 μm pixels coupled to a single SQUID. A further possibility is to increase the number of channels to be time-division multiplexed in a single column at some expense in resolution. In this paper we discuss experimental results and trade-offs for these extended array options.

A neurosurgical simulation of skull base tumors using a 3D printed rapid prototyping model containing mesh structures.

PubMed

Kondo, Kosuke; Harada, Naoyuki; Masuda, Hiroyuki; Sugo, Nobuo; Terazono, Sayaka; Okonogi, Shinichi; Sakaeyama, Yuki; Fuchinoue, Yutaka; Ando, Syunpei; Fukushima, Daisuke; Nomoto, Jun; Nemoto, Masaaki

2016-06-01

Deep regions are not visible in three-dimensional (3D) printed rapid prototyping (RP) models prepared from opaque materials, which is not the case with translucent images. The objectives of this study were to develop an RP model in which a skull base tumor was simulated using mesh, and to investigate its usefulness for surgical simulations by evaluating the visibility of its deep regions. A 3D printer that employs binder jetting and is mainly used to prepare plaster models was used. RP models containing a solid tumor, no tumor, and a mesh tumor were prepared based on computed tomography, magnetic resonance imaging, and angiographic data for four cases of petroclival tumor. Twelve neurosurgeons graded the three types of RP model into the following four categories: 'clearly visible,' 'visible,' 'difficult to see,' and 'invisible,' based on the visibility of the internal carotid artery, basilar artery, and brain stem through a craniotomy performed via the combined transpetrosal approach. In addition, the 3D positional relationships between these structures and the tumor were assessed. The internal carotid artery, basilar artery, and brain stem and the positional relationships of these structures with the tumor were significantly more visible in the RP models with mesh tumors than in the RP models with solid or no tumors. The deep regions of PR models containing mesh skull base tumors were easy to visualize. This 3D printing-based method might be applicable to various surgical simulations.

Pulmonary Drug Delivery Following Continuous Vibrating Mesh Nebulization and Inspiratory Synchronized Vibrating Mesh Nebulization During Noninvasive Ventilation in Healthy Volunteers.

PubMed

Michotte, Jean-Bernard; Staderini, Enrico; Aubriot, Anne-Sophie; Jossen, Emilie; Dugernier, Jonathan; Liistro, Giuseppe; Reychler, Gregory

2018-02-01

A breath-synchronized nebulization option that could potentially improve drug delivery during noninvasive positive pressure ventilation (NIPPV) is currently not available on single-limb circuit bilevel ventilators. The aim of this study was to compare urinary excretion of amikacin following aerosol delivery with a vibrating mesh nebulizer coupled to a single-limb circuit bilevel ventilator, using conventional continuous (Conti-Neb) and experimental inspiratory synchronized (Inspi-Neb) nebulization modes. A crossover clinical trial involving 6 noninvasive ventilated healthy volunteers (mean age of 32.3 ± 9.5 y) randomly assigned to both vibrating mesh nebulization modes was conducted: Inspi-Neb delivered aerosol during only the whole inspiratory phase, whereas Conti-Neb delivered aerosol continuously. All subjects inhaled amikacin solution (500 mg/4 mL) during NIPPV using a single-limb bilevel ventilator (inspiratory positive airway pressure: 12 cm H 2 O, and expiratory positive airway pressure: 5 cm H 2 O). Pulmonary drug delivery of amikacin following both nebulization modes was compared by urinary excretion of drug for 24 hours post-inhalation. The total daily amount of amikacin excreted in the urine was significantly higher with Inspi-Neb (median: 44.72 mg; interquartile range [IQR]: 40.50-65.13) than with Conti-Neb (median: 40.07 mg; IQR: 31.00-43.73), (p = 0.02). The elimination rate constant of amikacin (indirect measure of the depth of drug penetration into the lungs) was significantly higher with Inspi-Neb (median: 0.137; IQR: 0.113-0.146) than with Conti-Neb (median: 0.116; IQR: 0.105-0.130), (p = 0.02). However, the mean pulmonary drug delivery rate, expressed as the ratio between total daily urinary amount of amikacin and nebulization time, was significantly higher with Conti-Neb (2.03 mg/min) than with Inspi-Neb (1.09 mg/min) (p < 0.01). During NIPPV with a single-limb circuit bilevel ventilator, the use of inspiratory synchronized vibrating mesh nebulization may improve pulmonary drug delivery compared with conventional continuous vibrating mesh nebulization.

Tests of Scintillator+WLS Strips for Muon System at Future Colliders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denisov, Dmitri; Evdokimov, Valery; Lukić, Strahinja

2015-10-11

Prototype scintilator+WLS strips with SiPM readout for muon system at future colliders were tested for light yield, time resolution and position resolution. Depending on the configuration, light yield of up to 36 photoelectrons per muon per SiPM has been achieved, as well as time resolution of 0.5 ns and position resolution of ~ 7 cm.

Evaluation of a new rapid readout biological indicator for use in 132°C and 135°C vacuum-assisted steam sterilization cycles.

PubMed

Schneider, Philip M

2014-02-01

Sterilization is a process that cannot be inspected or tested in a practical manner to assure that all microorganisms have been inactivated. The process must therefore be validated for all of the specific items processed or monitored on a per cycle basis. A new, faster rapid readout biological indicator (RRBI) has been developed for use in 132°C and 135°C vacuum-assisted steam sterilization cycles. The aim of this study was to evaluate the performance of this new 1-hour readout RRBI at 132°C in side-by-side testing with an existing 3-hour readout RRBI and also evaluate the performance of the new RRBI in 135°C cycles. Readout responses of 1 hour (fluorescent) and 48 hours and 7 days (growth) of the new RRBI were compared with 3-hour, 48-hour, and 7-day readouts of the 3-hour RRBI following exposures in 132°C cycles using a highly controlled test vessel, ie, a steam resistometer. Additional testing of the 1-hour RRBIs was also performed in 135°C cycles. The number and percentage of fluorescent-positive 1-hour RRBIs were virtually identical to those of the 3-hour RRBIs after 1 and 3 hours of incubation, respectively. Testing of the 1-hour RRBI in 135°C cycles paralleled the results of the testing at 132°C but with the expected shorter exposure times. The results of this study suggest that the 1-hour RRBI is equivalent to the 3-hour RRBI and would be suitable for use in monitoring dynamic air removal steam sterilization cycles at both 132°C and 135°C per recommended practice guidelines. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Time and position resolution of the scintillator strips for a muon system at future colliders

DOE PAGES

Denisov, Dmitri; Evdokimov, Valery; Lukic, Strahinja

2016-03-31

In this study, prototype scintilator+WLS strips with SiPM readout for a muon system at future colliders were tested for light yield, time resolution and position resolution. Depending on the configuration, light yield of up to 36 photoelectrons per muon per SiPM has been observed, as well as time resolution of 0.45 ns and position resolution along the strip of 7.7 cm.

Polypropylene-based composite mesh versus standard polypropylene mesh in the reconstruction of complicated large abdominal wall hernias: a prospective randomized study.

PubMed

Kassem, M I; El-Haddad, H M

2016-10-01

To compare polypropylene mesh positioned onlay supported by omentum and/or peritoneum versus inlay implantation of polypropylene-based composite mesh in patients with complicated wide-defect ventral hernias. This was a prospective randomized study carried out on 60 patients presenting with complicated large ventral hernia in the period from January 2012 to January 2016 in the department of Gastrointestinal Surgery unit and Surgical Emergency of the Main Alexandria University Hospital, Egypt. Large hernia had an abdominal wall defect that could not be closed. Patients were divided into two groups of 30 patients according to the type of mesh used to deal with the large abdominal wall defect. The study included 38 women (63.3 %) and 22 men (37.7 %); their mean age was 46.5 years (range, 25-70). Complicated incisional hernia was the commonest presentation (56.7 %).The operative and mesh fixation times were longer in the polypropylene group. Seven wound infections and two recurrences were encountered in the propylene group. Mean follow-up was 28.7 months (2-48 months). Composite mesh provided, in one session, satisfactory results in patients with complicated large ventral hernia. The procedure is safe and effective in lowering operative time with a trend of low wound complication and recurrence rates.

Brown class III maxillectomy defects reconstruction with prefabricated titanium mesh and soft tissue free flap.

PubMed

Dediol, Emil; Uglešić, Vedran; Zubčić, Vedran; Knežević, Predrag

2013-07-01

Midface reconstruction is one of the most challenging tasks for the reconstructive surgeon. We present a technique for the reconstruction of the midface after total maxillectomy with preservation of orbital contents. Skeletal reconstruction is achieved with a preoperatively bent titanium sheet mesh on a universal skeletal model. The alveolar ridge, the anterior wall of the maxillary sinus, the zygomatic prominence, the lower orbital rim, and the orbital floor are reconstructed with a titanium mesh. A soft tissue free flap, preferably anterolateral thigh free flap, is harvested as well. A part of the flap is deepithelized and put in front of the mesh to prevent exposure, and the other part is used for palatal reconstruction. Four male and 1 female patients were reconstructed with titanium mesh. Four free flaps were raised: 3 anterolateral thigh and 1 latissimus dorsi. All free flaps survived. All patients received postoperative irradiation with 64 Gy. Median follow-up was 12 months; no major complications occurred. Mesh was exposed in only 1 case, which was managed successfully with resuspension of the heavy latissimus dorsi myocutaneous flap. Midface projection and height, globe position, ocular movements, and vision where satisfactory in all cases. Midface reconstruction with titanium mesh and soft tissue free flap is a reliable and safe method for functional and aesthetic reconstruction after maxillectomy.

Terahertz wave techniques using a metal mesh for evaluating the components of the stratum corneum.

PubMed

Mizukoshi, Koji; Yonekura, Kazuki; Ogura, Hidehiro; Guan, Yu; Kawase, Kodo

2013-02-01

Terahertz waves are located in the region of the spectrum between milliwaves and infrared. We analyzed the feasibility of terahertz spectroscopy to inspect the compositional variations of the stratum corneum (SC). We used a terahertz time-domain spectroscopy system with the metal mesh technique. To investigate whether terahertz can inspect compositional variation of SC, we measured the terahertz frequency spectra of the SC sheet that was treated with chloroform-methanol, lipid mixture, a denaturation agent, and heating with hot air. The chloroform-methanol treatment of the SC shifted the dip position, which represents a convex downward shape of the spectra, to a higher frequency. This dip shift was reversed to an untreated position by the dose-dependent application of a lipid mixture. The heating treatment of the SC shifted the dip position to a higher frequency. The same dip shift was also induced by the application of a denaturation agent to the SC. The technique using terahertz waves with a metal mesh is effective because of its simplicity and its high degree of accuracy in detecting the amount of lipid and the protein conformation state. © 2012 John Wiley & Sons A/S.

Method for making an elastomeric member with end pieces

DOEpatents

Hoppie, Lyle O.; McNinch, Jr., Joseph H.; Nowell, Gregory C.

1984-01-01

A molding process for molding an elongated elastomeric member (60) with wire mesh sleeves (16) bonded to the ends (14). A molding preform (10) of elastomeric material is positioned within a seamless mold cylinder (26), and the open ends of the wire mesh sleeves (16) are mounted to end plug assemblies (30) slidably received into the mold cylinder (26) and positioned against the ends (14) of the preform (10). A specialized profile is formed into surfaces (44) of the respective end plug assemblies (30) and by heating of the mold (26), the ends (14) of the elastomeric preform (10) are molded to the profile, as well as bonded to the reinforcing wire mesh sleeves (16). Vacuum is applied to the interior of the mold to draw outgassing vapors through relief spaces therethrough. The completed elastomeric member (60) is removed from the mold cylinder (26) by stretching, the consequent reduction in diameter enabling ready separation from the mold cylinder (26) and removal thereof.

Effective algal harvesting by using mesh membrane for enhanced energy recovery in an innovative integrated photobioelectrochemical system.

PubMed

Luo, Shuai; Sai Shankar Sampara, Pranav; He, Zhen

2018-04-01

In this work, an innovative design of integrated photobioelectrochemcial system (IPB) and an algal harvesting method based on polyester-mesh membrane (MM) were investigated. The algal growth/harvesting period of 6 days led to the highest surface biomass productivity (SBP) of 0.88 g m -2  day -1 and the highest energy generation of 0.157 ± 0.001 kJ day -1 . The harvesting frequency of 3 times in an operational cycle (with three pieces of MM) enhanced the SBP to 1.14 g m -2  day -1 . The catholyte recirculation for catholyte mixing resulted in a positive net energy production (NEP) of 0.227 ± 0.025 kJ day -1 . Those results have demonstrated the benefits of both using mesh membrane and the new reactor design for algal collection with positive effects on improving IPB performance. Copyright © 2018 Elsevier Ltd. All rights reserved.

Deterioration in biomechanical properties of the vagina following implantation of a high-stiffness prolapse mesh.

PubMed

Feola, A; Abramowitch, S; Jallah, Z; Stein, S; Barone, W; Palcsey, S; Moalli, P

2013-01-01

To define the impact of prolapse mesh on the biomechanical properties of the vagina by comparing the prototype Gynemesh PS (Ethicon) to two new-generation lower stiffness meshes, SmartMesh (Coloplast) and UltraPro (Ethicon). A study employing a nonhuman primate model. University of Pittsburgh, PA, USA. Forty-five parous rhesus macaques. Meshes were implanted via sacrocolpopexy after hysterectomy and compared with sham. Because its stiffness is highly directional, UltraPro was implanted in two directions: UltraPro Perpendicular (less stiff) and UltraPro Parallel (more stiff), with the indicated direction referring to the position of the blue orientation lines relative to the longitudinal axis of the vagina. The mesh-vaginal complex (MVC) was excised in toto after 3 months. Active mechanical properties were quantified as the contractile force generated in the presence of 120 mmol/l KCl. Passive mechanical properties (a tissue's ability to resist an applied force) were measured using a multiaxial protocol. Vaginal contractility decreased by 80% following implantation with the Gynemesh PS (P = 0.001), 48% after SmartMesh (P = 0.001), 68% after UltraPro Parallel (P = 0.001) and was highly variable after UltraPro Perpendicular (P = 0.16). The tissue contribution to the passive mechanical behaviour of the MVC was drastically reduced for Gynemesh PS (P = 0.003), but not for SmartMesh (P = 0.9) or UltraPro independent of the direction of implantation (P = 0.68 and P = 0.66, respectively). Deterioration of the mechanical properties of the vagina was highest following implantation with the stiffest mesh, Gynemesh PS. Such a decrease associated with implantation of a device of increased stiffness is consistent with findings from other systems employing prostheses for support. © 2013 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2013 RCOG.

Analysis of the vibratory excitation arising from spiral bevel gears

NASA Technical Reports Server (NTRS)

Mark, William D.

1987-01-01

Tools required to understand and predict in terms of its underlying causes the vibratory excitation arising from meshing spiral bevel gears are developed. A generalized three component transmission error of meshing spiral bevel gears is defined. Equations are derived that yield the three components of the generalized transmission error in terms of deviations of tooth running surfaces from equispaced perfect spherical involute surfaces and tooth/gearbody elastic deformations arising from the three components of the generalized force transmitted by the meshing gears. A method for incorporating these equations into the equations of motion of a gear system is described. Equations are derived for the three components of the generalized force transmitted by the gears which are valid whenever inertial effects of the meshing gears and their supports are negligible. Bearing offsets from the positions occupied by the shaft centerlines of perfect spherical involute bevel gears and bearing/bearing support flexibilities enter into the computation of these forces.

SU-E-T-176: Clinical Experience of Brass Mesh Bolus: Patient-Specific Parameters as Predictors of Measured Dosimetric Effect

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yock, A; Manger, R; Einck, J

2015-06-15

Purpose: Increasingly, brass mesh bolus is used to insure dosimetric coverage of the skin for patients treated post-mastectomy for breast cancer. Contribution of photoelectrons from interactions between the bolus and the primary beam increases dose superficially without affecting dose at greater depths. We present our experience using brass mesh bolus – including patients for whom the bolus was dosimetrically inadequate – along with analysis of relevant patient-specific parameters. Methods: Optically-stimulated luminescent dosimeters (OSLDs) were used to determine the effect of the bolus for 15 patients. They were positioned beneath the bolus within the tangent fields at three positions: 1.5–3cm insidemore » the medial and lateral field edges, and midway between the two. All OSLDs were midfield in the cranial-caudal direction. The measurements were compared with patient-specific parameters including separation, chest wall/breast tissue thickness, beam angle incidence, and planned surface dose. Results: The average OSLD measurement at the medial field edge, midfield, and lateral field edge position was 86.8%, 101.8%, and 92.8% of the prescription dose, respectively. A measurement for one patient was low enough (77.0%) to warrant a switch to an alternative type of bolus. Anatomic parameters were analyzed to investigate the low dose in this case, not observed in the planning system. The patient was observed to have a thin chest wall and very oblique beam angles. A second patient was also switched to an alternative type of bolus due to her being high risk and treated with an electron patch that extended onto the breast. Conclusion: Brass mesh bolus increases dose superficially while leaving dose at greater depths unaffected. However, our results suggest that this effect may be insufficient in patients with a thin chest wall or very oblique beam angles. More data and analysis is necessary to proactively identify patients for whom brass mesh bolus is effective.« less

Transport of phase space densities through tetrahedral meshes using discrete flow mapping

NASA Astrophysics Data System (ADS)

Bajars, Janis; Chappell, David J.; Søndergaard, Niels; Tanner, Gregor

2017-01-01

Discrete flow mapping was recently introduced as an efficient ray based method determining wave energy distributions in complex built up structures. Wave energy densities are transported along ray trajectories through polygonal mesh elements using a finite dimensional approximation of a ray transfer operator. In this way the method can be viewed as a smoothed ray tracing method defined over meshed surfaces. Many applications require the resolution of wave energy distributions in three-dimensional domains, such as in room acoustics, underwater acoustics and for electromagnetic cavity problems. In this work we extend discrete flow mapping to three-dimensional domains by propagating wave energy densities through tetrahedral meshes. The geometric simplicity of the tetrahedral mesh elements is utilised to efficiently compute the ray transfer operator using a mixture of analytic and spectrally accurate numerical integration. The important issue of how to choose a suitable basis approximation in phase space whilst maintaining a reasonable computational cost is addressed via low order local approximations on tetrahedral faces in the position coordinate and high order orthogonal polynomial expansions in momentum space.

Local mesh adaptation technique for front tracking problems

NASA Astrophysics Data System (ADS)

Lock, N.; Jaeger, M.; Medale, M.; Occelli, R.

1998-09-01

A numerical model is developed for the simulation of moving interfaces in viscous incompressible flows. The model is based on the finite element method with a pseudo-concentration technique to track the front. Since a Eulerian approach is chosen, the interface is advected by the flow through a fixed mesh. Therefore, material discontinuity across the interface cannot be described accurately. To remedy this problem, the model has been supplemented with a local mesh adaptation technique. This latter consists in updating the mesh at each time step to the interface position, such that element boundaries lie along the front. It has been implemented for unstructured triangular finite element meshes. The outcome of this technique is that it allows an accurate treatment of material discontinuity across the interface and, if necessary, a modelling of interface phenomena such as surface tension by using specific boundary elements. For illustration, two examples are computed and presented in this paper: the broken dam problem and the Rayleigh-Taylor instability. Good agreement has been obtained in the comparison of the numerical results with theory or available experimental data.

Laparoscopic transabdominal preperitoneal approach for umbilical hernia with rectus diastasis.

PubMed

Capitano, Sante

2017-08-01

Rectus diastasis, when coexistent with umbilical hernia, can benefit from mesh-based repair of the midline. Laparoscopic correction of an umbilical hernia involves the placement of a mesh in the peritoneal cavity, but this comes with the risk of bowel complications. However, newly developed dual-sided composite meshes have helped to reduce this risk. Four men and three women with umbilical hernia and rectus diastasis were treated with laparoscopic transabdominal preperitoneal repair. Composite mesh with a hydrophilic 3-D polyester textile on the parietal side and an absorbable collagen barrier on the peritoneal side were placed in the preperitoneal pocket after hernial sac reduction. Mean hernia size was 2.5 cm, and no recurrences were observed during the mean follow-up period of 9.2 months. The laparoscopic transabdominal preperitoneal approach for umbilical hernia and rectus diastasis may be a safe surgical option when trying to avoid potential complications related to intra-abdominal mesh positioning. © 2017 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.

Integration of the ATLAS FE-I4 Pixel Chip in the Mini Time Projection Chamber

NASA Astrophysics Data System (ADS)

Lopez-Thibodeaux, Mayra; Garcia-Sciveres, Maurice; Kadyk, John; Oliver-Mallory, Kelsey

2013-04-01

This project deals with development of readout for a Time Projection Chamber (TPC) prototype. This is a type of detector proposed for direct detection of dark matter (WIMPS) with direction information. The TPC is a gaseous charged particle tracking detector composed of a field cage and a gas avalanche detector. The latter is made of two Gas Electron Multipliers in series, illuminating a pixel readout integrated circuit, which measures the distribution in position and time of the output charge. We are testing the TPC prototype, filled with ArCO2 gas, using a Fe-55 x-ray source and cosmic rays. The present prototype uses an FE-I3 chip for readout. This chip was developed about 10 years ago and is presently in use within the ATLAS pixel detector at the LHC. The aim of this work is to upgrade the TPC prototype to use an FE-I4 chip. The FE-I4 has an active area of 336 mm^2 and 26880 pixels, over nine times the number of pixels in the FE-I3 chip, and an active area about six times as much. The FE-I4 chip represents the state of the art of pixel detector readout, and is presently being used to build an upgrade of the ATLAS pixel detector.

Prototype readout system for a multi Mpixels UV single-photon imaging detector capable of space flight operation

NASA Astrophysics Data System (ADS)

Seljak, A.; Cumming, H. S.; Varner, G.; Vallerga, J.; Raffanti, R.; Virta, V.

2018-02-01

Our collaboration works on the development of a large aperture, high resolution, UV single-photon imaging detector, funded through NASA's Strategic Astrophysics Technology (SAT) program. The detector uses a microchannel plate for charge multiplication, and orthogonal cross strip (XS) anodes for charge readout. Our target is to make an advancement in the technology readiness level (TRL), which enables real scale prototypes to be tested for future NASA missions. The baseline detector has an aperture of 50×50 mm and requires 160 low-noise charge-sensitive channels, in order to extrapolate the incoming photon position with a spatial resolution of about 20 μm FWHM. Technologies involving space flight require highly integrated electronic systems operating at very low power. We have designed two ASICs which enable the construction of such readout system. First, a charge sensitive amplifier (CSAv3) ASIC provides an equivalent noise charge (ENC) of around 600 e-, and a baseline gain of 10 mV/fC. The second, a Giga Sample per Second (GSPS) ASIC, called HalfGRAPH, is a 12-bit analog to digital converter. Its architecture is based on waveform sampling capacitor arrays and has about 8 μs of analog storage memory per channel. Both chips encapsulate 16 measurement channels. Using these chips, a small scale prototype readout system has been constructed on a FPGA Mezzanine Board (FMC), equipped with 32 measurement channels for system evaluation. We describe the construction of HalfGRAPH ASIC, detector's readout system concept and obtained results from the prototype system. As part of the space flight qualification, these chips were irradiated with a Cobalt gamma-ray source, to verify functional operation under ionizing radiation exposure.

Advanced X-ray Imaging Crystal Spectrometer for Magnetic Fusion Tokamak Devices

NASA Astrophysics Data System (ADS)

Lee, S. G.; Bak, J. G.; Bog, M. G.; Nam, U. W.; Moon, M. K.; Cheon, J. K.

2008-03-01

An advanced X-ray imaging crystal spectrometer is currently under development using a segmented position sensitive detector and time-to-digital converter (TDC) based delay-line readout electronics for burning plasma diagnostics. The proposed advanced XICS utilizes an eight-segmented position sensitive multi-wire proportional counter and supporting electronics to increase the spectrometer performance includes the photon count-rate capability and spatial resolution.

Readout for phase qubits without Josephson junctions

NASA Astrophysics Data System (ADS)

Steffen, Matthias; Kumar, Shwetank; DiVincenzo, David; Keefe, George; Ketchen, Mark; Rothwell, Mary Beth; Rozen, Jim

2010-03-01

We present a readout scheme for phase qubits which eliminates the read-out superconducting quantum interference device so that the entire qubit and measurement circuitry only require a single Josephson junction. Our scheme capacitively couples the phase qubit directly to a transmission line and detects its state after the measurement pulse by determining a frequency shift observable in the forward scattering parameter of the readout microwaves. This readout is extendable to multiple phase qubits coupled to a common readout line and can in principle be used for other flux biased qubits having two quasistable readout configurations.

Comparison of three different methods for effective introduction of platelet-rich plasma on PLGA woven mesh.

PubMed

Lee, Ji-Hye; Nam, Jinwoo; Kim, Hee Joong; Yoo, Jeong Joon

2015-03-11

For successful tissue regeneration, effective cell delivery to defect site is very important. Various types of polymer biomaterials have been developed and applied for effective cell delivery. PLGA (poly lactic-co-glycolic acid), a synthetic polymer, is a commercially available and FDA approved material. Platelet-rich plasma (PRP) is an autologous growth factor cocktail containing various growth factors including PDGF, TGFβ-1 and BMPs, and has shown positive effects on cell behaviors. We hypothesized that PRP pretreatment on PLGA mesh using different methods would cause different patterns of platelet adhesion and stages which would modulate cell adhesion and proliferation on the PLGA mesh. In this study, we pretreated PRP on PLGA using three different methods including simple dripping (SD), dynamic oscillation (DO) and centrifugation (CE), then observed the amount of adhered platelets and their activation stage distribution. The highest amount of platelets was observed on CE mesh and calcium treated CE mesh. Moreover, calcium addition after PRP coating triggered dramatic activation of platelets which showed large and flat morphologies of platelets with rich fibrin networks. Human chondrocytes (hCs) and human bone marrow stromal cells (hBMSCs) were next cultured on PRP-pretreated PLGA meshes using different preparation methods. CE mesh showed a significant increase in the initial cell adhesion of hCs and proliferation of hBMSCs compared with SD and DO meshes. The results demonstrated that the centrifugation method can be considered as a promising coating method to introduce PRP on PLGA polymeric material which could improve cell-material interaction using a simple method.

Influence of Basalt Mesh Induced Increase of Heterogeneity of Cement Composites with Dispersed Fibers on Its Resistance under Near-Field Blast

NASA Astrophysics Data System (ADS)

Zíma, J.; Foglar, M.

2017-09-01

This paper describes the influence of multiple basalt meshes in the cement composite specimens on the damage induced by near-field blast. Experimental measurements performed in the Boletice military area in 2014 and 2015 are evaluated by numerical simulations. The evaluation of the results is mainly focused on the stress propagation in the cement composite with dispersed fibers, the propagation of the overpressure caused by the blast and velocity of the ejected parts from the specimen. The influence of the presence and position of the basalt meshes in the specimen on its damage induced by delamination is also examined.

Single transmission-line readout method for silicon photomultiplier based time-of-flight and depth-of-interaction PET

NASA Astrophysics Data System (ADS)

Ko, Guen Bae; Lee, Jae Sung

2017-03-01

We propose a novel single transmission-line readout method for whole-body time-of-flight positron emission tomography applications, without compromising on performance. The basic idea of the proposed multiplexing method is the addition of a specially prepared tag signal ahead of the scintillation pulse. The tag signal is a square pulse that encodes photon arrival time and channel information. The 2D position of a silicon photomultiplier (SiPM) array is encoded by the specific width and height of the tag signal. A summing amplifier merges the tag and scintillation signals of each channel, and the final output signal can be acquired with a one-channel digitizer. The feasibility and performance of the proposed method were evaluated using a 1:1 coupled detector consisting of 4  ×  4 array of LGSO crystals and 16 channel SiPM. The sixteen 3 mm LGSO crystals were clearly separated in the crystal-positioning map with high reliability. The average energy resolution and coincidence resolving time were 11.31  ±  0.55% and 264.7  ±  10.7 ps, respectively. We also proved that the proposed method does not degrade timing performance with increasing multiplexing ratio. The two types of LGSO crystals (L0.95GSO and L0.20GSO) in phoswich detector were also clearly identified with the high-reliability using pulse shape discrimination, thanks to the well-preserved pulse shape information. In conclusion, the proposed multiplexing method allows decoding of the 3D interaction position of gamma rays in the scintillation detector with single-line readout.

Single transmission-line readout method for silicon photomultiplier based time-of-flight and depth-of-interaction PET.

PubMed

Ko, Guen Bae; Lee, Jae Sung

2017-03-21

We propose a novel single transmission-line readout method for whole-body time-of-flight positron emission tomography applications, without compromising on performance. The basic idea of the proposed multiplexing method is the addition of a specially prepared tag signal ahead of the scintillation pulse. The tag signal is a square pulse that encodes photon arrival time and channel information. The 2D position of a silicon photomultiplier (SiPM) array is encoded by the specific width and height of the tag signal. A summing amplifier merges the tag and scintillation signals of each channel, and the final output signal can be acquired with a one-channel digitizer. The feasibility and performance of the proposed method were evaluated using a 1:1 coupled detector consisting of 4  ×  4 array of LGSO crystals and 16 channel SiPM. The sixteen 3 mm LGSO crystals were clearly separated in the crystal-positioning map with high reliability. The average energy resolution and coincidence resolving time were 11.31  ±  0.55% and 264.7  ±  10.7 ps, respectively. We also proved that the proposed method does not degrade timing performance with increasing multiplexing ratio. The two types of LGSO crystals (L 0.95 GSO and L 0.20 GSO) in phoswich detector were also clearly identified with the high-reliability using pulse shape discrimination, thanks to the well-preserved pulse shape information. In conclusion, the proposed multiplexing method allows decoding of the 3D interaction position of gamma rays in the scintillation detector with single-line readout.

Retrofascial mesh repair of ventral incisional hernias.

PubMed

Le, Hamilton; Bender, Jeffrey S

2005-03-01

Recurrence rates after ventral incisional hernia repair are reported to be as high as 33% and are associated with considerable morbidity and lost time. The purpose of this study was to determine if retrofascial mesh placement reduces the incidence of recurrence as well as the severity of wound infections. A prospective database covering the period from January 1995 to June 2003 was maintained. All patients underwent a standardized technique by a single surgeon. Polypropylene mesh was placed between the fascia and the peritoneum with the fascia closed over the mesh. There were 150 patients (126 women, 24 men) with a mean age of 55 years. Their average weight was 88 kg, with an average body mass index of 32. Sixty-three (42%) of the hernias were recurrences of a previous repair. The average size of the hernia was 8 x 14 cm. There was 1 postoperative mortality. There was a 9% postoperative infection rate with 2 patients (1%) requiring mesh removal. Long-term follow-up evaluation has revealed 3 recurrences (2%) and 3 readmissions for bowel obstruction with 1 patient requiring surgical release. There were no fistulas noted. Incisional hernia repair with mesh placed in the retrofascial position decreases both the risk for recurrence and the severity of wound infection without significant problems from bowel obstruction or enteric fistula.

Implementation of non-axisymmetric mesh system in the gyrokinetic PIC code (XGC) for Stellarators

NASA Astrophysics Data System (ADS)

Moritaka, Toseo; Hager, Robert; Cole, Micheal; Chang, Choong-Seock; Lazerson, Samuel; Ku, Seung-Hoe; Ishiguro, Seiji

2017-10-01

Gyrokinetic simulation is a powerful tool to investigate turbulent and neoclassical transports based on the first-principles of plasma kinetics. The gyrokinetic PIC code XGC has been developed for integrated simulations that cover the entire region of Tokamaks. Complicated field line and boundary structures should be taken into account to demonstrate edge plasma dynamics under the influence of X-point and vessel components. XGC employs gyrokinetic Poisson solver on unstructured triangle mesh to deal with this difficulty. We introduce numerical schemes newly developed for XGC simulation in non-axisymmetric Stellarator geometry. Triangle meshes in each poloidal plane are defined by PEST poloidal angle in the VMEC equilibrium so that they have the same regular structure in the straight field line coordinate. Electric charge of marker particle is distributed to the triangles specified by the field-following projection to the neighbor poloidal planes. 3D spline interpolation in a cylindrical mesh is also used to obtain equilibrium magnetic field at the particle position. These schemes capture the anisotropic plasma dynamics and resulting potential structure with high accuracy. The triangle meshes can smoothly connect to unstructured meshes in the edge region. We will present the validation test in the core region of Large Helical Device and discuss about future challenges toward edge simulations.

Direct metal laser sintering (DMLS) of a customized titanium mesh for prosthetically guided bone regeneration of atrophic maxillary arches.

PubMed

Ciocca, L; Fantini, M; De Crescenzio, F; Corinaldesi, G; Scotti, R

2011-11-01

This study describes a protocol for the direct manufacturing of a customized titanium mesh using CAD-CAM procedures and rapid prototyping to augment maxillary bone and minimize surgery when severe atrophy or post-oncological deformities are present. Titanium mesh and particulate autogenous plus bovine demineralised bone were planned for patient rehabilitation. Bone augmentation planning was performed using the pre-op CT data set in relation to the prosthetic demands, minimizing the bone volume to augment at the minimum necessary for implants. The containment mesh design was used to prototype the 0.6 mm thickness customized titanium mesh, by direct metal laser sintering. The levels of regenerated bone were calculated using the post-op CT data set, through comparison with the pre-op CT data set. The mean vertical height difference of the crestal bone was 2.57 mm, while the mean buccal-palatal dimension of thickness difference was 3.41 mm. All planned implants were positioned after an 8 month healing period using two-step implant surgery, and finally restored with a partial fixed prosthesis. We present a viable and reproducible method to determine the correct bone augmentation prior to implant placement and CAD-CAM to produce a customized direct laser-sintered titanium mesh that can be used for bone regeneration.

Performance of a Micro-Strip Gas Chamber for event wise, high rate thermal neutron detection with accurate 2D position determination

NASA Astrophysics Data System (ADS)

Mindur, B.; Alimov, S.; Fiutowski, T.; Schulz, C.; Wilpert, T.

2014-12-01

A two-dimensional (2D) position sensitive detector for neutron scattering applications based on low-pressure gas amplification and micro-strip technology was built and tested with an innovative readout electronics and data acquisition system. This detector contains a thin solid neutron converter and was developed for time- and thus wavelength-resolved neutron detection in single-event counting mode, which improves the image contrast in comparison with integrating detectors. The prototype detector of a Micro-Strip Gas Chamber (MSGC) was built with a solid natGd/CsI thermal neutron converter for spatial resolutions of about 100 μm and counting rates up to 107 neutrons/s. For attaining very high spatial resolutions and counting rates via micro-strip readout with centre-of-gravity evaluation of the signal amplitude distributions, a fast, channel-wise, self-triggering ASIC was developed. The front-end chips (MSGCROCs), which are very first signal processing components, are read out into powerful ADC-FPGA boards for on-line data processing and thereafter via Gigabit Ethernet link into the data receiving PC. The workstation PC is controlled by a modular, high performance dedicated software suite. Such a fast and accurate system is crucial for efficient radiography/tomography, diffraction or imaging applications based on high flux thermal neutron beam. In this paper a brief description of the detector concept with its operation principles, readout electronics requirements and design together with the signals processing stages performed in hardware and software are presented. In more detail the neutron test beam conditions and measurement results are reported. The focus of this paper is on the system integration, two dimensional spatial resolution, the time resolution of the readout system and the imaging capabilities of the overall setup. The detection efficiency of the detector prototype is estimated as well.

Sensitivity encoded silicon photomultiplier--a new sensor for high-resolution PET-MRI.

PubMed

Schulz, Volkmar; Berker, Yannick; Berneking, Arne; Omidvari, Negar; Kiessling, Fabian; Gola, Alberto; Piemonte, Claudio

2013-07-21

Detectors for simultaneous positron emission tomography and magnetic resonance imaging in particular with sub-mm spatial resolution are commonly composed of scintillator crystal arrays, readout via arrays of solid state sensors, such as avalanche photo diodes (APDs) or silicon photomultipliers (SiPMs). Usually a light guide between the crystals and the sensor is used to enable the identification of crystals which are smaller than the sensor elements. However, this complicates crystal identification at the gaps and edges of the sensor arrays. A solution is to use as many sensors as crystals with a direct coupling, which unfortunately increases the complexity and power consumption of the readout electronics. Since 1997, position-sensitive APDs have been successfully used to identify sub-mm crystals. Unfortunately, these devices show a limitation in their time resolution and a degradation of spatial resolution when placed in higher magnetic fields. To overcome these limitations, this paper presents a new sensor concept that extends conventional SiPMs by adding position information via the spatial encoding of the channel sensitivity. The concept allows a direct coupling of high-resolution crystal arrays to the sensor with a reduced amount of readout channels. The theory of sensitivity encoding is detailed and linked to compressed sensing to compute unique sparse solutions. Two devices have been designed using one- and two-dimensional linear sensitivity encoding with eight and four readout channels, respectively. Flood histograms of both devices show the capability to precisely identify all 4 × 4 LYSO crystals with dimensions of 0.93 × 0.93 × 10 mm(3). For these crystals, the energy and time resolution (MV ± SD) of the devices with one (two)-dimensional encoding have been measured to be 12.3 · (1 ± 0.047)% (13.7 · (1 ± 0.047)%) around 511 keV with a paired coincidence time resolution (full width at half maximum) of 462 · (1 ± 0.054) ps (452 · (1 ± 0.078) ps).

Sensitivity encoded silicon photomultiplier—a new sensor for high-resolution PET-MRI

NASA Astrophysics Data System (ADS)

Schulz, Volkmar; Berker, Yannick; Berneking, Arne; Omidvari, Negar; Kiessling, Fabian; Gola, Alberto; Piemonte, Claudio

2013-07-01

Detectors for simultaneous positron emission tomography and magnetic resonance imaging in particular with sub-mm spatial resolution are commonly composed of scintillator crystal arrays, readout via arrays of solid state sensors, such as avalanche photo diodes (APDs) or silicon photomultipliers (SiPMs). Usually a light guide between the crystals and the sensor is used to enable the identification of crystals which are smaller than the sensor elements. However, this complicates crystal identification at the gaps and edges of the sensor arrays. A solution is to use as many sensors as crystals with a direct coupling, which unfortunately increases the complexity and power consumption of the readout electronics. Since 1997, position-sensitive APDs have been successfully used to identify sub-mm crystals. Unfortunately, these devices show a limitation in their time resolution and a degradation of spatial resolution when placed in higher magnetic fields. To overcome these limitations, this paper presents a new sensor concept that extends conventional SiPMs by adding position information via the spatial encoding of the channel sensitivity. The concept allows a direct coupling of high-resolution crystal arrays to the sensor with a reduced amount of readout channels. The theory of sensitivity encoding is detailed and linked to compressed sensing to compute unique sparse solutions. Two devices have been designed using one- and two-dimensional linear sensitivity encoding with eight and four readout channels, respectively. Flood histograms of both devices show the capability to precisely identify all 4 × 4 LYSO crystals with dimensions of 0.93 × 0.93 × 10 mm3. For these crystals, the energy and time resolution (MV ± SD) of the devices with one (two)-dimensional encoding have been measured to be 12.3 · (1 ± 0.047)% (13.7 · (1 ± 0.047)%) around 511 keV with a paired coincidence time resolution (full width at half maximum) of 462 · (1 ± 0.054) ps (452 · (1 ± 0.078) ps).

Precision star-tracking telescope

NASA Technical Reports Server (NTRS)

Fairbank, W. M.; Everitt, C. W. F.

1972-01-01

The design, construction, and preliminary testing of a new high accuracy star tracking telescope for the laboratory model of the Stanford gyro relativity experiment are described. The function of the telescope in the final flight experiment is to define (by reference to a suitable star) a direction in space for comparison with the relativistic precession of a group of gyroscopes. The design of the telescope has been strongly affected by designs for other portions of the overall experiments, for example the gyroscopes, the attitude control system of the satellite, and the instrumentation system used in processing relativity data. Main goals for the star tracker are: (1) independent readout of angular position in two planes; (2) absolute null stability over a one year period of mechanical parts; (3) readout linear to 0.001 arc-seconds over + or - 0.05 arc-second; (4) noise performance leading to a resolution of 0.05 arc-second in 0.1 second observation time of the chosen reference star; and (5) provision for automatic gain control capable of matching the gains of the gyroscopes and telescope readouts to 1% or better.

Development of X-ray CCD camera based X-ray micro-CT system

NASA Astrophysics Data System (ADS)

Sarkar, Partha S.; Ray, N. K.; Pal, Manoj K.; Baribaddala, Ravi; Agrawal, Ashish; Kashyap, Y.; Sinha, A.; Gadkari, S. C.

2017-02-01

Availability of microfocus X-ray sources and high resolution X-ray area detectors has made it possible for high resolution microtomography studies to be performed outside the purview of synchrotron. In this paper, we present the work towards the use of an external shutter on a high resolution microtomography system using X-ray CCD camera as a detector. During micro computed tomography experiments, the X-ray source is continuously ON and owing to the readout mechanism of the CCD detector electronics, the detector registers photons reaching it during the read-out period too. This introduces a shadow like pattern in the image known as smear whose direction is defined by the vertical shift register. To resolve this issue, the developed system has been incorporated with a synchronized shutter just in front of the X-ray source. This is positioned in the X-ray beam path during the image readout period and out of the beam path during the image acquisition period. This technique has resulted in improved data quality and hence the same is reflected in the reconstructed images.

Triroc: A Multi-Channel SiPM Read-Out ASIC for PET/PET-ToF Application

NASA Astrophysics Data System (ADS)

Ahmad, Salleh; Fleury, Julien; de la Taille, Christophe; Seguin-Moreau, Nathalie; Dulucq, Frederic; Martin-Chassard, Gisele; Callier, Stephane; Thienpont, Damien; Raux, Ludovic

2015-06-01

Triroc is the latest addition to SiPM readout ASICs family developed at Weeroc, a start-up company from the Omega microelectronics group of IN2P3/CNRS. This chip is developed under the framework TRIMAGE European project which is aimed for building a cost effective tri-modal PET/MR/EEG brain scan. To ensure the flexibility and compatibility with any SiPM in the market, the ASIC is designed to be capable of accepting negative and positive polarity input signals. This 64-channel ASIC, is suitable for SiPM readout which requires high accuracy timing and charge measurements. Targeted applications would be PET prototyping with time-of-flight capability. Main features of Triroc includes high dynamic range ADC up to 2500 photoelectrons and TDC fine time binning of 40 ps. Triroc requires very minimal external components which means it is a good contender for compact multichannel PET prototyping. Triroc is designed by using AMS 0.35 μm SiGe technology and it was submitted in March 2014. The detail design of this chip will be presented.

Improved charge injection device and a focal plane interface electronics board for stellar tracking

NASA Technical Reports Server (NTRS)

Michon, G. J.; Burke, H. K.

1984-01-01

An improved Charge Injection Device (CID) stellar tracking sensor and an operating sensor in a control/readout electronics board were developed. The sensor consists of a shift register scanned, 256x256 CID array organized for readout of 4x4 subarrays. The 4x4 subarrays can be positioned anywhere within the 256x256 array with a 2 pixel resolution. This allows continuous tracking of a number of stars simultaneously since nine pixels (3x3) centered on any star can always be read out. Organization and operation of this sensor and the improvements in design and semiconductor processing are described. A hermetic package incorporating an internal thermoelectric cooler assembled using low temperature solders was developed. The electronics board, which contains the sensor drivers, amplifiers, sample hold circuits, multiplexer, analog to digital converter, and the sensor temperature control circuits, is also described. Packaged sensors were evaluated for readout efficiency, spectral quantum efficiency, temporal noise, fixed pattern noise, and dark current. Eight sensors along with two tracker electronics boards were completed, evaluated, and delivered.

High Speed Large Format Photon Counting Microchannel Plate Imaging Sensors

NASA Astrophysics Data System (ADS)

Siegmund, O.; Ertley, C.; Vallerga, J.; Craven, C.; Popecki, M.; O'Mahony, A.; Minot, M.

The development of a new class of microchannel plate technology, using atomic layer deposition (ALD) techniques applied to a borosilicate microcapillary array is enabling the implementation of larger, more stable detectors for Astronomy and remote sensing. Sealed tubes with MCPs with SuperGenII, bialkali, GaAs and GaN photocathodes have been developed to cover a wide range of optical/UV sensing applications. Formats of 18mm and 25mm circular, and 50mm (Planacon) and 20cm square have been constructed for uses from night time remote reconnaissance and biological single-molecule fluorescence lifetime imaging microscopy, to large area focal plane imagers for Astronomy, neutron detection and ring imaging Cherenkov detection. The large focal plane areas were previously unattainable, but the new developments in construction of ALD microchannel plates allow implementation of formats of 20cm or more. Continuing developments in ALD microchannel plates offer improved overall sealed tube lifetime and gain stability, and furthermore show reduced levels of radiation induced background. High time resolution astronomical and remote sensing applications can be addressed with microchannel plate based imaging, photon time tagging detector sealed tube schemes. Photon counting imaging readouts for these devices vary from cross strip (XS), cross delay line (XDL), to stripline anodes, and pad arrays depending on the intended application. The XS and XDL readouts have been implemented in formats from 22mm, and 50mm to 20cm. Both use MCP charge signals detected on two orthogonal layers of conductive fingers to encode event X-Y positions. XDL readout uses signal propagation delay to encode positions while XS readout uses charge cloud centroiding. Spatial resolution readout of XS detectors can be better than 20 microns FWHM, with good image linearity while using low gain (<10^6), allowing high local counting rates and longer overall tube lifetime. XS tubes with electronics can encode event rates of >5 MHz and event timing accuracy of ~100ps. We will discuss how we are applying these detector system developments for devices in formats of 18mm and 25mm circular, and 50mm and 20cm square. The performance characteristics will be demonstrated along with lifetest data taken over the last year. Implications for ground based instruments to study transient and variable astronomical objects, as well as implementation in satellite instruments for earth atmospheric, planetary and solar observations will be discussed.

CFD simulation of a screw compressor including leakage flows and rotor heating

NASA Astrophysics Data System (ADS)

Spille-Kohoff, Andreas, Dr.; Hesse, Jan; El Shorbagy, Ahmed

2015-08-01

Computational Fluid Dynamics (CFD) simulations have promising potential to become an important part in the development process of positive displacement (PD) machines. CFD delivers deep insights into the flow and thermodynamic behaviour of PD machines. However, the numerical simulation of such machines is more complex compared to dynamic pumps like turbines or fans. The fluid transport in size-changing chambers with very small clearances between the rotors, and between rotors and casing, demands complex meshes that change with each time step. Additionally, the losses due to leakage flows and the heat transfer to the rotors need high-quality meshes so that automatic remeshing is almost impossible. In this paper, setup steps and results for the simulation of a dry screw compressor are shown. The rotating parts are meshed with TwinMesh, a special hexahedral meshing program for gear pumps, gerotors, lobe pumps and screw compressors. In particular, these meshes include axial and radial clearances between housing and rotors, and beside the fluid volume the rotor solids are also meshed. The CFD simulation accounts for gas flow with compressibility and turbulence effects, heat transfer between gas and rotors, and leakage flows through the clearances. We show time- resolved results for torques, forces, interlobe pressure, mass flow, and heat flow between gas and rotors, as well as time- and space-resolved results for pressure, velocity, temperature etc. for different discharge ports and working points of the screw compressor. These results are also used as thermal loads for deformation simulations of the rotors.

ICE: A Scalable, Low-Cost FPGA-Based Telescope Signal Processing and Networking System

NASA Astrophysics Data System (ADS)

Bandura, K.; Bender, A. N.; Cliche, J. F.; de Haan, T.; Dobbs, M. A.; Gilbert, A. J.; Griffin, S.; Hsyu, G.; Ittah, D.; Parra, J. Mena; Montgomery, J.; Pinsonneault-Marotte, T.; Siegel, S.; Smecher, G.; Tang, Q. Y.; Vanderlinde, K.; Whitehorn, N.

2016-03-01

We present an overview of the ‘ICE’ hardware and software framework that implements large arrays of interconnected field-programmable gate array (FPGA)-based data acquisition, signal processing and networking nodes economically. The system was conceived for application to radio, millimeter and sub-millimeter telescope readout systems that have requirements beyond typical off-the-shelf processing systems, such as careful control of interference signals produced by the digital electronics, and clocking of all elements in the system from a single precise observatory-derived oscillator. A new generation of telescopes operating at these frequency bands and designed with a vastly increased emphasis on digital signal processing to support their detector multiplexing technology or high-bandwidth correlators — data rates exceeding a terabyte per second — are becoming common. The ICE system is built around a custom FPGA motherboard that makes use of an Xilinx Kintex-7 FPGA and ARM-based co-processor. The system is specialized for specific applications through software, firmware and custom mezzanine daughter boards that interface to the FPGA through the industry-standard FPGA mezzanine card (FMC) specifications. For high density applications, the motherboards are packaged in 16-slot crates with ICE backplanes that implement a low-cost passive full-mesh network between the motherboards in a crate, allow high bandwidth interconnection between crates and enable data offload to a computer cluster. A Python-based control software library automatically detects and operates the hardware in the array. Examples of specific telescope applications of the ICE framework are presented, namely the frequency-multiplexed bolometer readout systems used for the South Pole Telescope (SPT) and Simons Array and the digitizer, F-engine, and networking engine for the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) radio interferometers.

Multi-Absorber Transition-Edge Sensors for X-Ray Astronomy Applications

NASA Technical Reports Server (NTRS)

Smith, S. J.; Adams, J. S.; Bandler, S. R.; Busch, S. E.; Chervenak, J. A.; Eckart, M. E.; Ewin, A. J.; Finkbeiner, F. M.; Kelley, R. L.; Kelly, D. P.;

Development of a Multiplexed Microsphere PCR for Culture-Free Detection and Gram-Typing of Bacteria in Human Blood Samples.

PubMed

Liang, Fang; Browne, Daniel J; Gray, Megan J; Gartlan, Kate H; Smith, David D; Barnard, Ross T; Hill, Geoffrey R; Corrie, Simon R; Markey, Kate A

2018-05-11

Bloodstream infection is a significant clinical problem, particularly in vulnerable patient groups such as those undergoing chemotherapy and bone marrow transplantation. Clinical diagnostics for suspected bloodstream infection remain centered around blood culture (highly variable timing, in the order of hours to days to become positive), and empiric use of broad-spectrum antibiotics is therefore employed for patients presenting with febrile neutropenia. Gram-typing provides the first opportunity to target therapy (e.g., combinations containing vancomycin or teicoplanin for Gram-positives; piperacillin-tazobactam or a carbapenem for Gram-negatives); however, current approaches require blood culture. In this study, we describe a multiplexed microsphere-PCR assay with flow cytometry readout, which can distinguish Gram-positive from Gram-negative bacterial DNA in a 3.5 h time period. The combination of a simple assay design (amplicon-dependent release of Gram-type specific Cy3-labeled oligonucleotides) and the Luminex-based readout (for quantifying each specific Cy3-labeled sequence) opens opportunities for further multiplexing. We demonstrate the feasibility of detecting common Gram-positive and Gram-negative organisms after spiking whole bacteria into healthy human blood prior to DNA extraction. Further development of DNA extraction methods is required to reach detection limits comparable to blood culture.

Technique for Calculating Solution Derivatives With Respect to Geometry Parameters in a CFD Code

NASA Technical Reports Server (NTRS)

Mathur, Sanjay

2011-01-01

A solution has been developed to the challenges of computation of derivatives with respect to geometry, which is not straightforward because these are not typically direct inputs to the computational fluid dynamics (CFD) solver. To overcome these issues, a procedure has been devised that can be used without having access to the mesh generator, while still being applicable to all types of meshes. The basic approach is inspired by the mesh motion algorithms used to deform the interior mesh nodes in a smooth manner when the surface nodes, for example, are in a fluid structure interaction problem. The general idea is to model the mesh edges and nodes as constituting a spring-mass system. Changes to boundary node locations are propagated to interior nodes by allowing them to assume their new equilibrium positions, for instance, one where the forces on each node are in balance. The main advantage of the technique is that it is independent of the volumetric mesh generator, and can be applied to structured, unstructured, single- and multi-block meshes. It essentially reduces the problem down to defining the surface mesh node derivatives with respect to the geometry parameters of interest. For analytical geometries, this is quite straightforward. In the more general case, one would need to be able to interrogate the underlying parametric CAD (computer aided design) model and to evaluate the derivatives either analytically, or by a finite difference technique. Because the technique is based on a partial differential equation (PDE), it is applicable not only to forward mode problems (where derivatives of all the output quantities are computed with respect to a single input), but it could also be extended to the adjoint problem, either by using an analytical adjoint of the PDE or a discrete analog.

Study of the counting efficiency of a WBC setup by using a computational 3D human body library in sitting position based on polygonal mesh surfaces.

PubMed

Fonseca, T C Ferreira; Bogaerts, R; Lebacq, A L; Mihailescu, C L; Vanhavere, F

2014-04-01

A realistic computational 3D human body library, called MaMP and FeMP (Male and Female Mesh Phantoms), based on polygonal mesh surface geometry, has been created to be used for numerical calibration of the whole body counter (WBC) system of the nuclear power plant (NPP) in Doel, Belgium. The main objective was to create flexible computational models varying in gender, body height, and mass for studying the morphology-induced variation of the detector counting efficiency (CE) and reducing the measurement uncertainties. First, the counting room and an HPGe detector were modeled using MCNPX (Monte Carlo radiation transport code). The validation of the model was carried out for different sample-detector geometries with point sources and a physical phantom. Second, CE values were calculated for a total of 36 different mesh phantoms in a seated position using the validated Monte Carlo model. This paper reports on the validation process of the in vivo whole body system and the CE calculated for different body heights and weights. The results reveal that the CE is strongly dependent on the individual body shape, size, and gender and may vary by a factor of 1.5 to 3 depending on the morphology aspects of the individual to be measured.

Improving Control of Two Motor Controllers

NASA Technical Reports Server (NTRS)

Toland, Ronald W.

2004-01-01

A computer program controls motors that drive translation stages in a metrology system that consists of a pair of two-axis cathetometers. This program is specific to Compumotor Gemini (or equivalent) motors and the Compumotor 6K-series (or equivalent) motor controller. Relative to the software supplied with the controller, this program affords more capabilities and is easier to use. Written as a Virtual Instrument in the LabVIEW software system, the program presents an imitation control panel that the user can manipulate by use of a keyboard and mouse. There are three modes of operation: command, movement, and joystick. In command mode, single commands are sent to the controller for troubleshooting. In movement mode, distance, speed, and/or acceleration commands are sent to the controller. Position readouts from the motors and from position encoders on the translation stages are displayed in marked fields. At any time, the position readouts can be recorded in a file named by the user. In joystick mode, the program yields control of the motors to a joystick. The program sends commands to, and receives data from, the controller via a serial cable connection, using the serial-communication portion of the software supplied with the controller.

Compact pulse width modulation circuitry for silicon photomultiplier readout.

PubMed

Bieniosek, M F; Olcott, P D; Levin, C S

2013-08-07

The adoption of solid-state photodetectors for positron emission tomography (PET) system design and the interest in 3D interaction information from PET detectors has lead to an increasing number of readout channels in PET systems. To handle these additional readout channels, PET readout electronics should be simplified to reduce the power consumption, cost, and size of the electronics for a single channel. Pulse-width modulation (PWM), where detector pulses are converted to digital pulses with width proportional to the detected photon energy, promises to simplify PET readout by converting the signals to digital form at the beginning of the processing chain, and allowing a single time-to-digital converter to perform the data acquisition for many channels rather than routing many analogue channels and digitizing in the back end. Integrator based PWM systems, also known as charge-to-time converters (QTCs), are especially compact, reducing the front-end electronics to an op-amp integrator with a resistor discharge, and a comparator. QTCs, however, have a long dead-time during which dark count noise is integrated, reducing the output signal-to-noise ratio. This work presents a QTC based PWM circuit with a gated integrator that shows performance improvements over existing QTC based PWM. By opening and closing an analogue switch on the input of the integrator, the circuit can be controlled to integrate only the portions of the signal with a high signal-to-noise ratio. It also allows for multiplexing different detectors into the same PWM circuit while avoiding uncorrelated noise propagation between photodetector channels. Four gated integrator PWM circuits were built to readout the spatial channels of two position sensitive solid-state photomultiplier (PS-SSPM). Results show a 4 × 4 array 0.9 mm × 0.9 mm × 15 mm of LYSO crystals being identified on the 5 mm × 5 mm PS-SSPM at room temperature with no degradation for twofold multiplexing. In principle, much larger multiplexing ratios are possible, limited only by count rate issues.

Side readout of long scintillation crystal elements with digital SiPM for TOF-DOI PET.

PubMed

Yeom, Jung Yeol; Vinke, Ruud; Levin, Craig S

2014-12-01

Side readout of scintillation light from crystal elements in positron emission tomography (PET) is an alternative to conventional end-readout configurations, with the benefit of being able to provide accurate depth-of-interaction (DOI) information and good energy resolution while achieving excellent timing resolution required for time-of-flight PET. This paper explores different readout geometries of scintillation crystal elements with the goal of achieving a detector that simultaneously achieves excellent timing resolution, energy resolution, spatial resolution, and photon sensitivity. The performance of discrete LYSO scintillation elements of different lengths read out from the end/side with digital silicon photomultipliers (dSiPMs) has been assessed. Compared to 3 × 3 × 20 mm(3) LYSO crystals read out from their ends with a coincidence resolving time (CRT) of 162 ± 6 ps FWHM and saturated energy spectra, a side-readout configuration achieved an excellent CRT of 144 ± 2 ps FWHM after correcting for timing skews within the dSiPM and an energy resolution of 11.8% ± 0.2% without requiring energy saturation correction. Using a maximum likelihood estimation method on individual dSiPM pixel response that corresponds to different 511 keV photon interaction positions, the DOI resolution of this 3 × 3 × 20 mm(3) crystal side-readout configuration was computed to be 0.8 mm FWHM with negligible artifacts at the crystal ends. On the other hand, with smaller 3 × 3 × 5 mm(3) LYSO crystals that can also be tiled/stacked to provide DOI information, a timing resolution of 134 ± 6 ps was attained but produced highly saturated energy spectra. The energy, timing, and DOI resolution information extracted from the side of long scintillation crystal elements coupled to dSiPM have been acquired for the first time. The authors conclude in this proof of concept study that such detector configuration has the potential to enable outstanding detector performance in terms of timing, energy, and DOI resolution.

Side readout of long scintillation crystal elements with digital SiPM for TOF-DOI PET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeom, Jung Yeol, E-mail: yeomjy@kumoh.ac.kr, E-mail: cslevin@stanford.edu; Vinke, Ruud; Levin, Craig S., E-mail: yeomjy@kumoh.ac.kr, E-mail: cslevin@stanford.edu

Purpose: Side readout of scintillation light from crystal elements in positron emission tomography (PET) is an alternative to conventional end-readout configurations, with the benefit of being able to provide accurate depth-of-interaction (DOI) information and good energy resolution while achieving excellent timing resolution required for time-of-flight PET. This paper explores different readout geometries of scintillation crystal elements with the goal of achieving a detector that simultaneously achieves excellent timing resolution, energy resolution, spatial resolution, and photon sensitivity. Methods: The performance of discrete LYSO scintillation elements of different lengths read out from the end/side with digital silicon photomultipliers (dSiPMs) has been assessed.more » Results: Compared to 3 × 3 × 20 mm{sup 3} LYSO crystals read out from their ends with a coincidence resolving time (CRT) of 162 ± 6 ps FWHM and saturated energy spectra, a side-readout configuration achieved an excellent CRT of 144 ± 2 ps FWHM after correcting for timing skews within the dSiPM and an energy resolution of 11.8% ± 0.2% without requiring energy saturation correction. Using a maximum likelihood estimation method on individual dSiPM pixel response that corresponds to different 511 keV photon interaction positions, the DOI resolution of this 3 × 3 × 20 mm{sup 3} crystal side-readout configuration was computed to be 0.8 mm FWHM with negligible artifacts at the crystal ends. On the other hand, with smaller 3 × 3 × 5 mm{sup 3} LYSO crystals that can also be tiled/stacked to provide DOI information, a timing resolution of 134 ± 6 ps was attained but produced highly saturated energy spectra. Conclusions: The energy, timing, and DOI resolution information extracted from the side of long scintillation crystal elements coupled to dSiPM have been acquired for the first time. The authors conclude in this proof of concept study that such detector configuration has the potential to enable outstanding detector performance in terms of timing, energy, and DOI resolution.« less

Trends and topics in eye disease research in PubMed from 2010 to 2014.

PubMed

Boudry, Christophe; Denion, Eric; Mortemousque, Bruno; Mouriaux, Fréderic

2016-01-01

The purpose of this study is to provide a report on scientific production during the period 2010-2014 in order to identify the major topics as well as the predominant actors (journals, countries, continents) involved in the field of eye disease. A PubMed search was carried out to extract articles related to eye diseases during the period 2010-2014. Data were downloaded and processed through developed PHP scripts for further analysis. A total of 62,123 articles were retrieved. A total of 3,368 different journals were found, and 19 journals were identified as "core journals" according to Braford's law. English was by far the predominant language. A total of 853,182 MeSH terms were found, representing an average of 13.73 (SD = 4.98) MeSH terms per article. Among these 853,182 MeSH terms, 14,689 different MeSH terms were identified. Vision Disorders, Glaucoma, Diabetic Retinopathy, Macular Degeneration, and Cataract were the most frequent five MeSH terms related to eye diseases. The analysis of the total number of publications showed that Europe and Asia were the most productive continents, and the USA and China the most productive countries. Interestingly, using the mean Five-Year Impact Factor, the two most productive continents were North America and Oceania. After adjustment for population, the overall ranking positions changed in favor of smaller countries (i.e. Iceland, Switzerland, Denmark, and New Zealand), while after adjustment for Gross Domestic Product (GDP), the overall ranking positions changed in favor of some developing countries (Malawi, Guatemala, Singapore). Due to the large number of articles included and the numerous parameters analyzed, this study provides a wide view of scientific productivity related to eye diseases during the period 2010-2014 and allows us to better understand this field.

Effects of Schwann cell alignment along the oriented electrospun chitosan nanofibers on nerve regeneration.

PubMed

Wang, Wei; Itoh, Soichiro; Konno, Katsumi; Kikkawa, Takeshi; Ichinose, Shizuko; Sakai, Katsuyoshi; Ohkuma, Tsuneo; Watabe, Kazuhiko

2009-12-15

We have constructed a chitosan nonwoven nanofiber mesh tube consisting of oriented fibers by the electrospinning method. The efficacy of oriented nanofibers on Schwann cell alignment and positive effect of this tube on peripheral nerve regeneration were confirmed. The physical properties of the chitosan nanofiber mesh sheets prepared by electrospinning with or without fiber orientation were characterized. Then, immortalized Schwann cells were cultured on these sheets. Furthermore, the chitosan nanofiber mesh tubes with or without orientation, and bilayered chitosan mesh tube with an inner layer of oriented nanofibers and an outer layer of randomized nanofibers were bridgegrafted into rat sciatic nerve defect. As a result of fiber orientation, the tensile strength along the axis of the sheet increased. Because Schwann cells aligned along the nanofibers, oriented fibrous sheets could exhibit a Schwann cell column. Functional recovery and electrophysiological recovery occurred in time in the oriented group as well as in the bilayered group, and approximately matched those in the isograft. Furthermore, histological analysis revealed that the sprouting of myelinated axons occurred vigorously followed by axonal maturation in the isograft, oriented, and bilayered group in the order. The oriented chitosan nanofiber mesh tube may be a promising substitute for autogenous nerve graft.

Grating droplets with a mesh

NASA Astrophysics Data System (ADS)

Soto, Dan; Le Helloco, Antoine; Clanet, Cristophe; Quere, David; Varanasi, Kripa

2016-11-01

A drop thrown against a mesh can pass through its holes if impacting with enough inertia. As a result, although part of the droplet may remain on one side of the sieve, the rest will end up grated through the other side. This inexpensive method to break up millimetric droplets into micrometric ones may be of particular interest in a wide variety of applications: enhancing evaporation of droplets launched from the top of an evaporative cooling tower or preventing drift of pesticides sprayed above crops by increasing their initial size and atomizing them at the very last moment with a mesh. In order to understand how much liquid will be grated we propose in this presentation to start first by studying a simpler situation: a drop impacting a plate pierced with a single off centered hole. The study of the role of natural parameters such as the radius drop and speed or the hole position, size and thickness allows us to discuss then the more general situation of a plate pierced with multiple holes: the mesh.

Alveolar Ridge Reconstruction with Titanium Meshes and Simultaneous Implant Placement: A Retrospective, Multicenter Clinical Study

PubMed Central

Paraud Freixas, Andres; Han, Chang-Hun; Bechara, Sohueil; Tawil, Isaac

2016-01-01

Objective. To evaluate horizontal bone gain and implant survival and complication rates in patients treated with titanium meshes placed simultaneously with dental implants and fixed over them. Methods. Twenty-five patients treated with 40 implants and simultaneous guided bone regeneration with titanium meshes (i–Gen®, MegaGen, Gyeongbuk, Republic of Korea) were selected for inclusion in the present retrospective multicenter study. Primary outcomes were horizontal bone gain and implant survival; secondary outcomes were biological and prosthetic complications. Results. After the removal of titanium meshes, the CBCT evaluation revealed a mean horizontal bone gain of 3.67 mm (±0.89). The most frequent complications were mild postoperative edema (12/25 patients: 48%) and discomfort after surgery (10/25 patients: 40%); these complications were resolved within one week. Titanium mesh exposure occurred in 6 patients (6/25 : 24%): one of these suffered partial loss of the graft and another experienced complete graft loss and implant failure. An implant survival rate of 97.5% (implant-based) and a peri-implant marginal bone loss of 0.43 mm (±0.15) were recorded after 1 year. Conclusions. The horizontal ridge reconstruction with titanium meshes placed simultaneously with dental implants achieved predictable satisfactory results. Prospective randomized controlled trials on a larger sample of patients are required to validate these positive outcomes. PMID:27999799

Tuning fork enhanced interferometric photoacoustic spectroscopy: a new method for trace gas analysis

NASA Astrophysics Data System (ADS)

Köhring, M.; Pohlkötter, A.; Willer, U.; Angelmahr, M.; Schade, W.

2011-01-01

A photoacoustic trace gas sensor based on an optical read-out method of a quartz tuning fork is shown. Instead of conventional piezoelectric signal read-out, as applied in well-known quartz-enhanced photoacoustic spectroscopy (QEPAS), an interferometric read-out method for measurement of the tuning fork's oscillation is presented. To demonstrate the potential of the optical read-out of tuning forks in photoacoustics, a comparison between the performances of a sensor with interferometric read-out and conventional QEPAS with piezoelectric read-out is reported. The two sensors show similar characteristics. The detection limit (L) for the optical read-out is determined to be L opt=(2598±84) ppm (1 σ) compared to L elec=(2579±78) ppm (1 σ) for piezoelectric read-out. In both cases the detection limit is defined by the thermal noise of the tuning fork.

Axial-Centrifugal Compressor Program

DTIC Science & Technology

1975-10-01

chip detector, but they were not large enough to trigger the alarm circuit. These chips we-e analyzed as M50 bearing material, which was a positive...but an analysis of these particles indicated M50 bearing material and positively identified a thrust bearing problem. 50 ’ ! i VI Figure 18. Load Cel...load cell readout became erratic and the vehicle was shut down. An inspection showed that the aft bearing sump chip detector contained M50 bearing

Fast, high-fidelity readout of multiple qubits

NASA Astrophysics Data System (ADS)

Bronn, N. T.; Abdo, B.; Inoue, K.; Lekuch, S.; Córcoles, A. D.; Hertzberg, J. B.; Takita, M.; Bishop, L. S.; Gambetta, J. M.; Chow, J. M.

2017-05-01

Quantum computing requires a delicate balance between coupling quantum systems to external instruments for control and readout, while providing enough isolation from sources of decoherence. Circuit quantum electrodynamics has been a successful method for protecting superconducting qubits, while maintaining the ability to perform readout [1, 2]. Here, we discuss improvements to this method that allow for fast, high-fidelity readout. Specifically, the integration of a Purcell filter, which allows us to increase the resonator bandwidth for fast readout, the incorporation of a Josephson parametric converter, which enables us to perform high-fidelity readout by amplifying the readout signal while adding the minimum amount of noise required by quantum mechanics, and custom control electronics, which provide us with the capability of fast decision and control.

Combining spray nozzle simulators with meshes: characterization of rainfall intensity and drop properties

NASA Astrophysics Data System (ADS)

Carvalho, Sílvia C. P.; de Lima, João L. M. P.; de Lima, M. Isabel P.

2013-04-01

Rainfall simulators can be a powerful tool to increase our understanding of hydrological and geomorphological processes. Nevertheless, rainfall simulators' design and operation might be rather demanding, for achieving specific rainfall intensity distributions and drop characteristics. The pressurized simulators have some advantages over the non-pressurized simulators: drops do not rely on gravity to reach terminal velocity, but are sprayed out under pressure; pressurized simulators also yield a broad range of drop sizes in comparison with drop-formers simulators. The main purpose of this study was to explore in the laboratory the potential of combining spray nozzle simulators with meshes in order to change rainfall characteristics (rainfall intensity and diameters and fall speed of drops). Different types of spray nozzles were tested, such as single full-cone and multiple full-cone nozzles. The impact of the meshes on the simulated rain was studied by testing different materials (i.e. plastic and steel meshes), square apertures and wire thicknesses, and different vertical distances between the nozzle and the meshes underneath. The diameter and fall speed of the rain drops were measured using a Laser Precipitation Monitor (Thies Clima). The rainfall intensity range and coefficients of uniformity of the sprays and the drop size distribution, fall speed and kinetic energy were analysed. Results show that when meshes intercept drop trajectories the spatial distribution of rainfall intensity and the drop size distribution are affected. As the spray nozzles generate typically small drop sizes and narrow drop size distributions, meshes can be used to promote the formation of bigger drops and random their landing positions.

THz near-field spectral encoding imaging using a rainbow metasurface.

PubMed

Lee, Kanghee; Choi, Hyun Joo; Son, Jaehyeon; Park, Hyun-Sung; Ahn, Jaewook; Min, Bumki

2015-09-24

We demonstrate a fast image acquisition technique in the terahertz range via spectral encoding using a metasurface. The metasurface is composed of spatially varying units of mesh filters that exhibit bandpass features. Each mesh filter is arranged such that the centre frequencies of the mesh filters are proportional to their position within the metasurface, similar to a rainbow. For imaging, the object is placed in front of the rainbow metasurface, and the image is reconstructed by measuring the transmitted broadband THz pulses through both the metasurface and the object. The 1D image information regarding the object is linearly mapped into the spectrum of the transmitted wave of the rainbow metasurface. Thus, 2D images can be successfully reconstructed using simple 1D data acquisition processes.

Compact laser interferometer for translation and tilt measurement as optical readout for the LISA inertial sensor

NASA Astrophysics Data System (ADS)

Schuldt, Thilo; Gohlke, Martin; Weise, Dennis; Johann, Ulrich; Peters, Achim; Braxmaier, Claus

2007-10-01

The space mission LISA (Laser Interferometer Space Antenna) aims at detecting gravitational waves in the frequency range 30 μ Hz to 1Hz. Free flying proof masses inside the satellites act as inertial sensors and represent the end mirrors of the interferometer. In the current baseline design, LISA utilizes an optical readout of the position and tilt of the proof mass with respect to the satellite housing. This readout must have ~ 5pm/√Hz sensitivity for the translation measurement (for frequencies above 2.8mHz with an ƒ -2 relaxation down to 30 μHz) and ~ 10 nrad/√Hz sensitivity for the tilt measurement (for frequencies above 0.1mHz with an ƒ -1 relaxation down to 30 μHz). The University of Applied Sciences Konstanz (HTWG) - in collaboration with Astrium GmbH, Friedrichshafen, and the Humboldt-University Berlin - therefore develops a highly symmetric heterodyne interferometer implementing differential wavefront sensing for the tilt measurement. We realized a mechanically highly stable and compact setup. In a second, improved setup we measured initial noise levels below 5 pm/√Hz and 10 nrad/√Hz, respectively, for frequencies above 10mHz.

Present and Future Applications of Digital Electronics in Nuclear Science - a Commercial Prospective

NASA Astrophysics Data System (ADS)

Tan, Hui

2011-10-01

Digital readout electronics instrumenting radiation detectors have experienced significant advancements in the last decade or so. This on one hand can be attributed to the steady improvements in commercial digital processing components such as analog-to-digital converters (ADCs), digital-to-analog converters (DACs), field-programmable-gate-arrays (FPGAs), and digital-signal-processors (DSPs), and on the other hand can also be attributed to the increasing needs for improved time, position, and energy resolution in nuclear physics experiments, which have spurred the rapid development of commercial off-the-shelf high speed, high resolution digitizers or spectrometers. Absent from conventional analog electronics, the capability to record fast decaying pulses from radiation detectors in digital readout electronics has profoundly benefited nuclear physics researchers since they now can perform detailed pulse processing for applications such as gamma-ray tracking and decay-event selection and reconstruction. In this talk, present state-of-the-art digital readout electronics and its applications in a variety of nuclear science fields will be discussed, and future directions in hardware development for digital electronics will also be outlined, all from the prospective of a commercial manufacturer of digital electronics.

Single-shot EPI with Nyquist ghost compensation: Interleaved Dual-Echo with Acceleration (IDEA) EPI

PubMed Central

Poser, Benedikt A; Barth, Markus; Goa, Pål-Erik; Deng, Weiran; Stenger, V Andrew

2012-01-01

Echo planar imaging is most commonly used for BOLD fMRI, owing to its sensitivity and acquisition speed. A major problem with EPI is Nyquist (N/2) ghosting, most notably at high field. EPI data are acquired under an oscillating readout gradient and hence vulnerable to gradient imperfections such as eddy current delays and off-resonance effects, as these cause inconsistencies between odd and even k-space lines after time reversal. We propose a straightforward and pragmatic method herein termed Interleaved Dual Echo with Acceleration (IDEA) EPI: Two k-spaces (echoes) are acquired under the positive and negative readout lobes, respectively, by performing phase blips only before alternate readout gradients. From these two k-spaces, two almost entirely ghost free images per shot can be constructed, without need for phase correction. The doubled echo train length can be compensated by parallel imaging and/or partial Fourier acquisition. The two k-spaces can either be complex-averaged during reconstruction, which results in near-perfect cancellation of residual phase errors, or reconstructed into separate images. We demonstrate the efficacy of IDEA EPI and show phantom and in vivo images at both 3 and 7 Tesla. PMID:22411762

Optical elements design of optical pick-up with characteristics of read-out spot for high density optical storage

NASA Astrophysics Data System (ADS)

Li, Lihua; Ma, Jianshe; Liu, Lin; Pan, Longfa; Zhang, Jianyong; Lu, Junhui

2005-09-01

It is well known that the optical pick-up (OPU) plays a very important role in optical storage system. And the quality of OPU can be measured by the characteristics of OPU read-out spot for high density optical storage. Therefore this paper mainly designs an OPU model for high density optical storage to study the characteristics of OPU read-out spot. Firstly it analyses the optical read-out principle in OPU and contrives an optical read-out system based on the hereinbefore theory. In this step it chiefly designs the grating, splitter, collimator lens and objective lens. Secondly based on the aberrations analysis and theory involved by the splitter, the collimator lens and the optical lens, the paper uses the software CODE V to calculate the aberrations and to optimize the optical read-out system. Then the author can receive an ideal OPU read-out spot for high density optical storage and obtain the characteristics of the ideal OPU read-out spot. At the same time this paper analyses some influence factors which can directly affect the characteristics of the OPU read-out spot. Thirdly according to the up data the author practically manufactures a real optical pick-up to validate the hereinbefore designed optical read-out system. And it uses the Optical Spot Analyzer to get the image of the read-out spot. Comparing the ideal image to the actual image of the designed optical read-out system, the author finds out that the upwards analyses and design is suitable for high density storage and can be used in the actual production. And the author also receives the conclusion that the mostly influences on characteristics of OPU read-out spot for high density optical storage factors is not only the process of designing the grating, splitter, collimator lens and objective lens, but also the assembling work precision

Luciferase-Specific Coelenterazine Analogues for Optical Contamination-Free Bioassays.

PubMed

Nishihara, Ryo; Abe, Masahiro; Nishiyama, Shigeru; Citterio, Daniel; Suzuki, Koji; Kim, Sung Bae

2017-04-19

Spectral overlaps among the multiple optical readouts commonly cause optical contamination in fluorescence and bioluminescence. To tackle this issue, we created five-different lineages of coelenterazine (CTZ) analogues designed to selectively illuminate a specific luciferase with unique luciferase selectivity. In the attempt, we found that CTZ analogues with ethynyl or styryl groups display dramatically biased bioluminescence to specific luciferases and pHs by modifying the functional groups at the C-2 and C-6 positions of the imidazopyradinone backbone of CTZ. The optical contamination-free feature was exemplified with the luciferase-specific CTZ analogues, which illuminated anti-estrogenic and rapamycin activities in a mixture of optical probes. This unique bioluminescence platform has great potential for specific and high throughput imaging of multiple optical readouts in bioassays without optical contamination.

Colour-barcoded magnetic microparticles for multiplexed bioassays.

PubMed

Lee, Howon; Kim, Junhoi; Kim, Hyoki; Kim, Jiyun; Kwon, Sunghoon

2010-09-01

Encoded particles have a demonstrated value for multiplexed high-throughput bioassays such as drug discovery and clinical diagnostics. In diverse samples, the ability to use a large number of distinct identification codes on assay particles is important to increase throughput. Proper handling schemes are also needed to readout these codes on free-floating probe microparticles. Here we create vivid, free-floating structural coloured particles with multi-axis rotational control using a colour-tunable magnetic material and a new printing method. Our colour-barcoded magnetic microparticles offer a coding capacity easily into the billions with distinct magnetic handling capabilities including active positioning for code readouts and active stirring for improved reaction kinetics in microscale environments. A DNA hybridization assay is done using the colour-barcoded magnetic microparticles to demonstrate multiplexing capabilities.

Quantum memory receiver for superadditive communication using binary coherent states

NASA Astrophysics Data System (ADS)

Klimek, Aleksandra; Jachura, Michał; Wasilewski, Wojciech; Banaszek, Konrad

2016-11-01

We propose a simple architecture based on multimode quantum memories for collective readout of classical information keyed using a pair coherent states, exemplified by the well-known binary phase shift keying format. Such a configuration enables demonstration of the superadditivity effect in classical communication over quantum channels, where the transmission rate becomes enhanced through joint detection applied to multiple channel uses. The proposed scheme relies on the recently introduced idea to prepare Hadamard sequences of input symbols that are mapped by a linear optical transformation onto the pulse position modulation format [Guha, S. Phys. Rev. Lett. 2011, 106, 240502]. We analyze two versions of readout based on direct detection and an optional Dolinar receiver which implements the minimum-error measurement for individual detection of a binary coherent state alphabet.

Quantum memory receiver for superadditive communication using binary coherent states.

PubMed

Klimek, Aleksandra; Jachura, Michał; Wasilewski, Wojciech; Banaszek, Konrad

2016-11-12

We propose a simple architecture based on multimode quantum memories for collective readout of classical information keyed using a pair coherent states, exemplified by the well-known binary phase shift keying format. Such a configuration enables demonstration of the superadditivity effect in classical communication over quantum channels, where the transmission rate becomes enhanced through joint detection applied to multiple channel uses. The proposed scheme relies on the recently introduced idea to prepare Hadamard sequences of input symbols that are mapped by a linear optical transformation onto the pulse position modulation format [Guha, S. Phys. Rev. Lett. 2011 , 106 , 240502]. We analyze two versions of readout based on direct detection and an optional Dolinar receiver which implements the minimum-error measurement for individual detection of a binary coherent state alphabet.

Particle tracking with a Timepix based triple GEM detector

NASA Astrophysics Data System (ADS)

George, S. P.; Murtas, F.; Alozy, J.; Curioni, A.; Rosenfeld, A. B.; Silari, M.

2015-11-01

This paper details the response of a triple GEM detector with a 55 μmetre pitch pixelated ASIC for readout. The detector is operated as a micro TPC with 9.5 cm3 sensitive volume and characterized with a mixed beam of 120 GeV protons and positive pions. A process for reconstruction of incident particle tracks from individual ionization clusters is described and scans of the gain and drift fields are performed. The angular resolution of the measured tracks is characterized. Also, the readout was operated in a mixed mode where some pixels measure drift time and others charge. This was used to measure the energy deposition in the detector and the charge cloud size as a function of interaction depth. The future uses of the device, including in microdosimetry are discussed.

Developing LAr Scintillation Light Collection Ideas in the Short Baseline Neutrino Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szelc, A. M.

2016-02-08

Scintillation light is becoming the most rapidly developing feature of Liquid Argon Time Projection Chamber (LArTPC) neutrino detectors due to its capability to enhance and expand their physics reach traditionally based on charge readout. The SBND detector, set to be built on the Booster Neutrino Beam Line at Fermilab, is in a unique position to test novel liquid argon scintillation light readout systems in a detector with physics neutrino events. The different ideas under consideration by the collaboration are described, including an array of PMTs detecting direct light, SiPM coupled lightguide bars and a setup which uses PMTs/SiPMS and wavelengthmore » shifter covered reflector foils, as well as their respective strengths and physics foci and the benchmarks used to compare them.« less

Performance study of large area encoding readout MRPC

NASA Astrophysics Data System (ADS)

Chen, X. L.; Wang, Y.; Chen, G.; Han, D.; Wang, X.; Zeng, M.; Zeng, Z.; Zhao, Z.; Guo, B.

2018-02-01

Muon tomography system built by the 2-D readout high spatial resolution Multi-gap Resistive Plate Chamber (MRPC) detector is a project of Tsinghua University. An encoding readout method based on the fine-fine configuration has been used to minimize the number of the readout electronic channels resulting in reducing the complexity and the cost of the system. In this paper, we provide a systematic comparison of the MRPC detector performance with and without fine-fine encoding readout. Our results suggest that the application of the fine-fine encoding readout leads us to achieve a detecting system with slightly worse spatial resolution but dramatically reduce the number of electronic channels.

[Evaluation of Image Quality of Readout Segmented EPI with Readout Partial Fourier Technique].

PubMed

Yoshimura, Yuuki; Suzuki, Daisuke; Miyahara, Kanae

Readout segmented EPI (readout segmentation of long variable echo-trains: RESOLVE) segmented k-space in the readout direction. By using the partial Fourier method in the readout direction, the imaging time was shortened. However, the influence on image quality due to insufficient data sampling is concerned. The setting of the partial Fourier method in the readout direction in each segment was changed. Then, we examined signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and distortion ratio for changes in image quality due to differences in data sampling. As the number of sampling segments decreased, SNR and CNR showed a low value. In addition, the distortion ratio did not change. The image quality of minimum sampling segments is greatly different from full data sampling, and caution is required when using it.

Infrared readout electronics; Proceedings of the Meeting, Orlando, FL, Apr. 21, 22, 1992

NASA Technical Reports Server (NTRS)

Fossum, Eric R. (Editor)

1992-01-01

The present volume on IR readout electronics discusses cryogenic readout using silicon devices, cryogenic readout using III-V and LTS devices, multiplexers for higher temperatures, and focal-plane signal processing electronics. Attention is given to the optimization of cryogenic CMOS processes for sub-10-K applications, cryogenic measurements of aerojet GaAs n-JFETs, inP-based heterostructure device technology for ultracold readout applications, and a three-terminal semiconductor-superconductor transimpedance amplifier. Topics addressed include unfulfilled needs in IR astronomy focal-plane readout electronics, IR readout integrated circuit technology for tactical missile systems, and radiation-hardened 10-bit A/D for FPA signal processing. Also discussed are the implementation of a noise reduction circuit for spaceflight IR spectrometers, a real-time processor for staring receivers, and a fiber-optic link design for INMOS transputers.

High-Fidelity Rapid Initialization and Read-Out of an Electron Spin via the Single Donor D(-) Charge State.

PubMed

Watson, T F; Weber, B; House, M G; Büch, H; Simmons, M Y

2015-10-16

We demonstrate high-fidelity electron spin read-out of a precision placed single donor in silicon via spin selective tunneling to either the D(+) or D(-) charge state of the donor. By performing read-out at the stable two electron D(0)↔D(-) charge transition we can increase the tunnel rates to a nearby single electron transistor charge sensor by nearly 2 orders of magnitude, allowing faster qubit read-out (1 ms) with minimum loss in read-out fidelity (98.4%) compared to read-out at the D(+)↔D(0) transition (99.6%). Furthermore, we show that read-out via the D(-) charge state can be used to rapidly initialize the electron spin qubit in its ground state with a fidelity of F(I)=99.8%.

An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras.

PubMed

Bolotnikov, A E; Ackley, K; Camarda, G S; Cherches, C; Cui, Y; De Geronimo, G; Fried, J; Hodges, D; Hossain, A; Lee, W; Mahler, G; Maritato, M; Petryk, M; Roy, U; Salwen, C; Vernon, E; Yang, G; James, R B

2015-07-01

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm(3) detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays' performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

Improved Airborne System for Sensing Wildfires

NASA Technical Reports Server (NTRS)

McKeown, Donald; Richardson, Michael

2008-01-01

The Wildfire Airborne Sensing Program (WASP) is engaged in a continuing effort to develop an improved airborne instrumentation system for sensing wildfires. The system could also be used for other aerial-imaging applications, including mapping and military surveillance. Unlike prior airborne fire-detection instrumentation systems, the WASP system would not be based on custom-made multispectral line scanners and associated custom- made complex optomechanical servomechanisms, sensors, readout circuitry, and packaging. Instead, the WASP system would be based on commercial off-the-shelf (COTS) equipment that would include (1) three or four electronic cameras (one for each of three or four wavelength bands) instead of a multispectral line scanner; (2) all associated drive and readout electronics; (3) a camera-pointing gimbal; (4) an inertial measurement unit (IMU) and a Global Positioning System (GPS) receiver for measuring the position, velocity, and orientation of the aircraft; and (5) a data-acquisition subsystem. It would be necessary to custom-develop an integrated sensor optical-bench assembly, a sensor-management subsystem, and software. The use of mostly COTS equipment is intended to reduce development time and cost, relative to those of prior systems.

Experimental study of boron-coated straws with a neutron source

NASA Astrophysics Data System (ADS)

Xie, Zhaoyang; Zhou, Jianrong; Song, Yushou; Lacy, Jeffrey L.; Sun, Liang; Sun, Zhijia; Hu, Bitao; Chen, Yuanbo

2018-04-01

Multiple types of high quality neutron detectors are proposed for the first phase of the China Spallation Neutron Source (CSNS), which will be commissioned in 2018. Considering the shortage of 3He supply, a detector module composed of 49 boron-coated straws (BCS) was developed by Proportional Technologies Inc. (PTI). Each straw has a length of 1000 mm and a diameter of 7.5 mm. Seven straws are tightly packed in a tube, and seven tubes are organized in a row to form a detector module. The charge division method is used for longitudinal positioning. A specific readout system was utilized to output the signal and simultaneously encode each straw. The performance of this detector module was studied using a moderated 252Cf source at the Institute of High Energy Physics (IHEP). The signal amplitude spectrum indicates its n-gamma discrimination capability. Despite the complex readout method, a longitudinal resolution of FWHM=6.1 ± 0.5 mm was obtained. The three-dimensional positioning ability qualifies this BCS detector module as a promising detector for small angle neutron scattering.

A multiplexed TOF and DOI capable PET detector using a binary position sensitive network.

PubMed

Bieniosek, M F; Cates, J W; Levin, C S

2016-11-07

Time of flight (TOF) and depth of interaction (DOI) capabilities can significantly enhance the quality and uniformity of positron emission tomography (PET) images. Many proposed TOF/DOI PET detectors require complex readout systems using additional photosensors, active cooling, or waveform sampling. This work describes a high performance, low complexity, room temperature TOF/DOI PET module. The module uses multiplexed timing channels to significantly reduce the electronic readout complexity of the PET detector while maintaining excellent timing, energy, and position resolution. DOI was determined using a two layer light sharing scintillation crystal array with a novel binary position sensitive network. A 20 mm effective thickness LYSO crystal array with four 3 mm  ×  3 mm silicon photomultipliers (SiPM) read out by a single timing channel, one energy channel and two position channels achieved a full width half maximum (FWHM) coincidence time resolution of 180  ±  2 ps with 10 mm of DOI resolution and 11% energy resolution. With sixteen 3 mm  ×  3 mm SiPMs read out by a single timing channel, one energy channel and four position channels a coincidence time resolution 204  ±  1 ps was achieved with 10 mm of DOI resolution and 15% energy resolution. The methods presented here could significantly simplify the construction of high performance TOF/DOI PET detectors.

Data Processing for a High Resolution Preclinical PET Detector Based on Philips DPC Digital SiPMs

NASA Astrophysics Data System (ADS)

Schug, David; Wehner, Jakob; Goldschmidt, Benjamin; Lerche, Christoph; Dueppenbecker, Peter Michael; Hallen, Patrick; Weissler, Bjoern; Gebhardt, Pierre; Kiessling, Fabian; Schulz, Volkmar

2015-06-01

In positron emission tomography (PET) systems, light sharing techniques are commonly used to readout scintillator arrays consisting of scintillation elements, which are smaller than the optical sensors. The scintillating element is then identified evaluating the signal heights in the readout channels using statistical algorithms, the center of gravity (COG) algorithm being the simplest and mostly used one. We propose a COG algorithm with a fixed number of input channels in order to guarantee a stable calculation of the position. The algorithm is implemented and tested with the raw detector data obtained with the Hyperion-II D preclinical PET insert which uses Philips Digital Photon Counting's (PDPC) digitial SiPMs. The gamma detectors use LYSO scintillator arrays with 30 ×30 crystals of 1 ×1 ×12 mm3 in size coupled to 4 ×4 PDPC DPC 3200-22 sensors (DPC) via a 2-mm-thick light guide. These self-triggering sensors are made up of 2 ×2 pixels resulting in a total of 64 readout channels. We restrict the COG calculation to a main pixel, which captures most of the scintillation light from a crystal, and its (direct and diagonal) neighboring pixels and reject single events in which this data is not fully available. This results in stable COG positions for a crystal element and enables high spatial image resolution. Due to the sensor layout, for some crystals it is very likely that a single diagonal neighbor pixel is missing as a result of the low light level on the corresponding DPC. This leads to a loss of sensitivity, if these events are rejected. An enhancement of the COG algorithm is proposed which handles the potentially missing pixel separately both for the crystal identification and the energy calculation. Using this advancement, we show that the sensitivity of the Hyperion-II D insert using the described scintillator configuration can be improved by 20-100% for practical useful readout thresholds of a single DPC pixel ranging from 17-52 photons. Furthermore, we show that the energy resolution of the scanner is superior for all readout thresholds if singles with a single missing pixel are accepted and correctly handled compared to the COG method only accepting singles with all neighbors present by 0-1.6% (relative difference). The presented methods can not only be applied to gamma detectors employing DPC sensors, but can be generalized to other similarly structured and self-triggering detectors, using light sharing techniques, as well.

Orbital Reconstruction: Patient-Specific Orbital Floor Reconstruction Using a Mirroring Technique and a Customized Titanium Mesh.

PubMed

Tarsitano, Achille; Badiali, Giovanni; Pizzigallo, Angelo; Marchetti, Claudio

2016-10-01

Enophthalmos is a severe complication of primary reconstruction of orbital floor fractures. The goal of secondary reconstruction procedures is to restore symmetrical globe positions to recover function and aesthetics. The authors propose a new method of orbital floor reconstruction using a mirroring technique and a customized titanium mesh, printed using a direct metal laser-sintering method. This reconstructive protocol involves 4 steps: mirroring of the healthy orbit at the affected site, virtual design of a patient-specific orbital floor mesh, CAM procedures for direct laser-sintering of the customized titanium mesh, and surgical insertion of the device. Using a computed tomography data set, the normal, uninjured side of the craniofacial skeleton was reflected onto the contralateral injured side, and a reconstructive orbital floor mesh was designed virtually on the mirrored orbital bone surface. The solid-to-layer files of the mesh were then manufactured using direct metal laser sintering, which resolves the shaping and bending biases inherent in the indirect method. An intraoperative navigation system ensured accuracy of the entire procedure. Clinical outcomes were assessed using 3dMD photogrammetry and computed tomography data in 7 treated patients. The technique described here appears to be a viable method to correct complex orbital floor defects needing delayed reconstruction. This study represents the first step in the development of a wider experimental protocol for orbital floor reconstruction using computer-assisted design-computer-assisted manufacturing technology.

An unstructured-mesh finite-volume MPDATA for compressible atmospheric dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kühnlein, Christian, E-mail: christian.kuehnlein@ecmwf.int; Smolarkiewicz, Piotr K., E-mail: piotr.smolarkiewicz@ecmwf.int

An advancement of the unstructured-mesh finite-volume MPDATA (Multidimensional Positive Definite Advection Transport Algorithm) is presented that formulates the error-compensative pseudo-velocity of the scheme to rely only on face-normal advective fluxes to the dual cells, in contrast to the full vector employed in previous implementations. This is essentially achieved by expressing the temporal truncation error underlying the pseudo-velocity in a form consistent with the flux-divergence of the governing conservation law. The development is especially important for integrating fluid dynamics equations on non-rectilinear meshes whenever face-normal advective mass fluxes are employed for transport compatible with mass continuity—the latter being essential for flux-formmore » schemes. In particular, the proposed formulation enables large-time-step semi-implicit finite-volume integration of the compressible Euler equations using MPDATA on arbitrary hybrid computational meshes. Furthermore, it facilitates multiple error-compensative iterations of the finite-volume MPDATA and improved overall accuracy. The advancement combines straightforwardly with earlier developments, such as the nonoscillatory option, the infinite-gauge variant, and moving curvilinear meshes. A comprehensive description of the scheme is provided for a hybrid horizontally-unstructured vertically-structured computational mesh for efficient global atmospheric flow modelling. The proposed finite-volume MPDATA is verified using selected 3D global atmospheric benchmark simulations, representative of hydrostatic and non-hydrostatic flow regimes. Besides the added capabilities, the scheme retains fully the efficacy of established finite-volume MPDATA formulations.« less

A family of position- and orientation-independent embedded boundary methods for viscous flow and fluid-structure interaction problems

NASA Astrophysics Data System (ADS)

Huang, Daniel Z.; De Santis, Dante; Farhat, Charbel

2018-07-01

The Finite Volume method with Exact two-material Riemann Problems (FIVER) is both a computational framework for multi-material flows characterized by large density jumps, and an Embedded Boundary Method (EBM) for computational fluid dynamics and highly nonlinear Fluid-Structure Interaction (FSI) problems. This paper deals with the EBM aspect of FIVER. For FSI problems, this EBM has already demonstrated the ability to address viscous effects along wall boundaries, and large deformations and topological changes of such boundaries. However, like for most EBMs - also known as immersed boundary methods - the performance of FIVER in the vicinity of a wall boundary can be sensitive with respect to the position and orientation of this boundary relative to the embedding mesh. This is mainly due to ill-conditioning issues that arise when an embedded interface becomes too close to a node of the embedding mesh, which may lead to spurious oscillations in the computed solution gradients at the wall boundary. This paper resolves these issues by introducing an alternative definition of the active/inactive status of a mesh node that leads to the removal of all sources of potential ill-conditioning from all spatial approximations performed by FIVER in the vicinity of a fluid-structure interface. It also makes two additional contributions. The first one is a new procedure for constructing the fluid-structure half Riemann problem underlying the semi-discretization by FIVER of the convective fluxes. This procedure eliminates one extrapolation from the conventional treatment of the wall boundary conditions and replaces it by an interpolation, which improves robustness. The second contribution is a post-processing algorithm for computing quantities of interest at the wall that achieves smoothness in the computed solution and its gradients. Lessons learned from these enhancements and contributions that are triggered by the new definition of the status of a mesh node are then generalized and exploited to eliminate from the original version of the FIVER method its sensitivities with respect to both of the position and orientation of the wall boundary relative to the embedding mesh, while maintaining the original definition of the status of a mesh node. This leads to a family of second-generation FIVER methods whose performance is illustrated in this paper for several flow and FSI problems. These include a challenging flow problem over a bird wing characterized by a feather-induced surface roughness, and a complex flexible flapping wing problem for which experimental data is available.

A new third order finite volume weighted essentially non-oscillatory scheme on tetrahedral meshes

NASA Astrophysics Data System (ADS)

Zhu, Jun; Qiu, Jianxian

2017-11-01

In this paper a third order finite volume weighted essentially non-oscillatory scheme is designed for solving hyperbolic conservation laws on tetrahedral meshes. Comparing with other finite volume WENO schemes designed on tetrahedral meshes, the crucial advantages of such new WENO scheme are its simplicity and compactness with the application of only six unequal size spatial stencils for reconstructing unequal degree polynomials in the WENO type spatial procedures, and easy choice of the positive linear weights without considering the topology of the meshes. The original innovation of such scheme is to use a quadratic polynomial defined on a big central spatial stencil for obtaining third order numerical approximation at any points inside the target tetrahedral cell in smooth region and switch to at least one of five linear polynomials defined on small biased/central spatial stencils for sustaining sharp shock transitions and keeping essentially non-oscillatory property simultaneously. By performing such new procedures in spatial reconstructions and adopting a third order TVD Runge-Kutta time discretization method for solving the ordinary differential equation (ODE), the new scheme's memory occupancy is decreased and the computing efficiency is increased. So it is suitable for large scale engineering requirements on tetrahedral meshes. Some numerical results are provided to illustrate the good performance of such scheme.

Structural Analysis and Application of n-Alkyl Cyanoacrylate Surgical Adhesives to the Fixation of Meshes for Hernia Repair.

PubMed

Fernández-Gutiérrez, Mar; Rodriguez-Mancheño, Marta; Pérez-Köhler, Bárbara; Pascual, Gemma; Bellón, Juan Manuel; Román, Julio San

2016-12-01

The article deals with a comparative analysis of the parameters of the polymerization in physiological conditions of three commercially available alkyl cyanoacrylates, n-butyl cyanoacrylate (GLUBRAN 2), n-hexyl cyanoacrylate (IFABOND), and n-octyl cyanoacrylate (EVOBOND), the cell behavior of the corresponding polymers and the application of these adhesives in the fixation of surgical polypropylene meshes for hernia repair in an animal model of rabbits. The results obtained demonstrate that the curing process depends on the nature of the alkyl residue of the ester group of cyanoacrylate molecules, being the heat of polymerization lower for the octyl derivative in comparison with the hexyl and butyl, and reaching a maximum temperature of 35 °C after a time of mixing with physiological fluids of 60-70 s. The cell behavior demonstrates that the three systems do not present toxicity for fibroblasts and low adhesion of cells, which is a positive result for application as tissue adhesives, especially for the fixation of abdominal polypropylene meshes for hernia repair. The animal experimentation indicates the excellent tolerance of the meshes fixed with the cyanoacrylic adhesives, during at least a period of 90 d, and guarantees a good adhesion for the application of hernia repair meshes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Temperature Stabilization of the NIFFTE Time Projection Chamber

NASA Astrophysics Data System (ADS)

Hicks, Caleb

2017-09-01

The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) is a collaboration measuring nuclear fission cross sections for use in advanced nuclear reactors. A neutron beam incident on targets of Uranium-235, Uranium-238, and Plutonium-239 is used to measure the neutron induced fission cross sections for these isotopes. A Time Projection Chamber (TPC) is used to record these reactions. Significant heat is generated by the readout cards mounted on the TPC, which are cooled by fans. One proposed measurement of the experiment is to compare the cross sections of the target to a proton target of gaseous hydrogen. A constant temperature inside the TPC's pressure vessel is desirable to maintain a constant number of hydrogen target atoms. In addition, a constant temperature minimizes the strain and wrinkles on an amplifying mesh inside the TPC. This poster describes the successful work to develop, build, and install a fan controller using a Raspberry Pi, an Arduino, and a custom circuit board to implement an algorithm called Proportional-Integral-Derivative control. This research was supported by US DOE MENP Grant DE-FG02-03ER41243.

Development of a one-dimensional Position Sensitive Detector for tracking applications

NASA Astrophysics Data System (ADS)

Lydecker, Leigh Kent, IV

Optical Position Sensitive Detectors (PSDs) are a non-contact method of tracking the location of a light spot. Silicon-based versions of such sensors are fabricated with standard CMOS processing, are inexpensive and provide a real-time, analog signal output corresponding to the position of the light spot. Because they are non-contact, they do not degrade over time from surface friction due to repetitive sliding motion associated with standard full contact sliding potentiometers. This results in long, reliable device lifetimes. In this work, an innovative PSD was developed to replace the linear hard contact potentiometer currently being used in a human-computer interface architecture. First, a basic lateral effect PSD was developed to provide real-time positioning of the mouthpiece used in the interface architecture which tracks along a single axis. During the course of this work, multiple device geometries were fabricated and analyzed resulting in a down selection of a final design. This final device design was then characterized in terms of resolution and responsivity and produced in larger quantities as initial prototypes for the test product integration. Finally, an electronic readout circuit was developed in order to interface the dual- line lateral effect PSD developed in this thesis with specifications required for product integration. To simplify position sensing, an innovative type of optical position sensor was developed using a linear photodiodes with back-to-back connections. This so- called Self-Balancing Position Sensitive Detector (SBPSD) requires significantly fewer processing steps than the basic lateral effect position sensitive detector discussed above and eliminates the need for external readout circuitry entirely. Prototype devices were fabricated in this work, and the performance characteristics of these devices were established paving the way for ultimate integration into the target product as well as additional applications.

Influence of local meshing size on stress intensity factor of orthopedic lag screw

NASA Astrophysics Data System (ADS)

Husain, M. N.; Daud, R.; Basaruddin, K. S.; Mat, F.; Bajuri, M. Y.; Arifin, A. K.

2017-09-01

Linear elastic fracture mechanics (LEFM) concept is generally used to study the influence of crack on the performance of structures. In order to study the LEFM concept on damaged structure, the usage of finite element analysis software is implemented to do the simulation of the structure. Mesh generation is one of the most crucial procedures in finite element method. For the structure that crack or damaged, it is very important to determine the accurate local meshing size at the crack tip of the crack itself in order to get the accurate value of stress intensity factor, KI. Pre crack will be introduced to the lag screw based on the von mises' stress result that had been performed in previous research. This paper shows the influence of local mesh arrangement on numerical value of the stress intensity factor, KI obtained by the displacement method. This study aims to simulate the effect of local meshing which is the singularity region on stress intensity factor, KI to the critical point of failure in screw. Five different set of wedges meshing size are introduced during the simulation of finite element analysis. The number of wedges used to simulate this research is 8, 10, 14, 16 and 20. There are three set of numerical equations used to validate the results which are brown and srawley, gross and brown and Tada equation. The result obtained from the finite element software (ANSYS APDL) has a positive agreement with the numerical analysis which is Brown and Srawley compared to other numerical formula. Radius of first row size of 0.014 and singularity element with 14 numbers of wedges is proved to be the best local meshing for this study.

Ventral incisional hernia (VIH) repair after liver transplantation (OLT) with a biological mesh: experience in 3 cases.

PubMed

Schaffellner, S; Sereinigg, M; Wagner, D; Jakoby, E; Kniepeiss, D; Stiegler, P; Haybäck, J; Müller, H

2016-05-01

Hernias after orthotopic liver transplant (OLT) occur in about 30 % of cases. Predisposing factors in liver cirrhotic patients of cases are ascites, low abdominal muscle mass and cachexia before and immunosuppression after OLT. Standard operative transplant-technique even in small hernias is to implant a mesh. For patients after liver transplantation a porcine non-cross linked biological patch being less immunogenic than synthetic and cross-linked meshes is chosen for ventral incisional hernia repair. 3 patients (1 female, 2 male), OLT indications Hepatitis C, exogenous- toxic cirrhosis, median-age 53 (51 - 56) and median time to hernia occurrence after OLT were 10 month (6 - 18 m) are documented. 2 patients suffered from diabetes, 2 from chronic-obstructive lung disease. Maintenance immunosuppressions were Everolimus in 1 patient, Everolimus + MMF in the second and Everolimus +Tacrolimus in the third patient. The biological was chosen for hernia repair due to the preexisting risk- factors. Meshes, 10 × 16 cm were placed, in IPOM (Intra-Peritonel-Onlay-Mesh) -position by relaparatomy. Insolvable, monofile, interrupted sutures were used. All patients recovered primarily, and were dismissed within 10 d post OP. No wound healing disorders or signs of postoperative infections occurred. All are free of hernia recurrence in a mean observation time of 22 month (10 - 36). The usage of porcine non-cross-linked biological patches seems feasible for incisional hernia repair after OLT. Wound infections in these patients have been observed with other meshes. Further investigation is needed to prove potential superiority of this biological to the other meshes. © Georg Thieme Verlag KG Stuttgart · New York.

Half-State Readout In Vertical-Bloch-Line Memory

NASA Technical Reports Server (NTRS)

Katti, Romney R.; Wu, Jiin-Chuan; Stadler, Henry L.

1994-01-01

Potentially narrow margins of chirality-based chopping of magnetic stripes avoided. Half-state readout is experimental method of readout in Vertical-Bloch-Line (VBL) memory. Based on differential deflections of magnetic stripe domains in which data bits stored. To give meaning to explanation of half-state readout, see "Vertical-Bloch-Line Memory" (NPO-18467).

46 CFR 154.1375 - Readout for temperature measuring device: Marking.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Readout for temperature measuring device: Marking. 154..., Construction and Equipment Instrumentation § 154.1375 Readout for temperature measuring device: Marking. Each readout under § 154.1340 for a device that measures temperature in a cargo tank must be marked with the...

46 CFR 154.1375 - Readout for temperature measuring device: Marking.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Readout for temperature measuring device: Marking. 154..., Construction and Equipment Instrumentation § 154.1375 Readout for temperature measuring device: Marking. Each readout under § 154.1340 for a device that measures temperature in a cargo tank must be marked with the...

46 CFR 154.1375 - Readout for temperature measuring device: Marking.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Readout for temperature measuring device: Marking. 154..., Construction and Equipment Instrumentation § 154.1375 Readout for temperature measuring device: Marking. Each readout under § 154.1340 for a device that measures temperature in a cargo tank must be marked with the...

46 CFR 154.1375 - Readout for temperature measuring device: Marking.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Readout for temperature measuring device: Marking. 154..., Construction and Equipment Instrumentation § 154.1375 Readout for temperature measuring device: Marking. Each readout under § 154.1340 for a device that measures temperature in a cargo tank must be marked with the...

46 CFR 154.1375 - Readout for temperature measuring device: Marking.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Readout for temperature measuring device: Marking. 154..., Construction and Equipment Instrumentation § 154.1375 Readout for temperature measuring device: Marking. Each readout under § 154.1340 for a device that measures temperature in a cargo tank must be marked with the...

The Background-Limited Infrared Submillimeter Spectrograph (BLISS) for SPICA: A Design Study

NASA Astrophysics Data System (ADS)

Bradford, Charles; BLISS-SPICA Study Team

2010-05-01

The far-IR waveband carries half of the photon energy ever produced in galaxies and quasars, evidence of the major role of dust-obscured processes in bringing about the modern Universe. The bulk of this appears to have occurred in the first half of the Universe's history (z>1). We are developing the Background-Limited Infrared-Submillimeter Spectrograph (BLISS) to capitalize on SPICA's cold telescope and provide a breakthrough far-IR spectroscopy capability. BLISS-SPICA is 6 orders of magnitude faster than the spectrometers on Herschel and SOFIA in obtaining full-band spectra, and will observe dust-obscured galaxies at all epochs back to the first billion years after the Big Bang (redshift 6), BLISS-SPICA thus probes the complete history of dust-obscured star formation and black-hole growth. It will also be extremely powerful for studying ice-giant planet formation in protoplanetary disks, with its sensitivity to very small amounts of gas. BLISS covers the 38-433 micron range in five grating-spectrometer bands, with two simultaneous sky positions. The detector package is 4224 silicon-nitride micro-mesh leg-isolated bolometers with superconducting transition-edge-sensed (TES) thermistors, read out with a cryogenic time-domain multiplexer, all cooled to 50mK for optimal sensitivity. All technical elements of BLISS have heritage in mature scientific instruments, and many have flown. We report on our design study in which we are optimizing performance while accommodating SPICA's constraints, including the stringent cryogenic mass budget. We present the science case for BLISS, as well as our progress in all key technical aspects: 1) opto-mechanical instrument architecture, 2) detector and readout approach, and 3) sub-K cooling approach. We thank the NASA for support of the BLISS study.

An RBF-based reparameterization method for constrained texture mapping.

PubMed

Yu, Hongchuan; Lee, Tong-Yee; Yeh, I-Cheng; Yang, Xiaosong; Li, Wenxi; Zhang, Jian J

2012-07-01

Texture mapping has long been used in computer graphics to enhance the realism of virtual scenes. However, to match the 3D model feature points with the corresponding pixels in a texture image, surface parameterization must satisfy specific positional constraints. However, despite numerous research efforts, the construction of a mathematically robust, foldover-free parameterization that is subject to positional constraints continues to be a challenge. In the present paper, this foldover problem is addressed by developing radial basis function (RBF)-based reparameterization. Given initial 2D embedding of a 3D surface, the proposed method can reparameterize 2D embedding into a foldover-free 2D mesh, satisfying a set of user-specified constraint points. In addition, this approach is mesh free. Therefore, generating smooth texture mapping results is possible without extra smoothing optimization.

Ozone production of hollow-needle-to-mesh negative corona discharge enhanced by dielectric tube on the needle electrode

NASA Astrophysics Data System (ADS)

Pekárek, Stanislav

2014-12-01

For the hollow-needle-to-mesh negative corona discharge in air, we studied the effect of placing the dielectric tube on the needle electrode and the effect of various positions of the end of this tube with respect to the tip of the needle electrode on the concentration of ozone produced by the discharge, the ozone production yield and the discharge V-A characteristics. We found that the placement of the dielectric tube on the needle electrode with a suitable position of this tube end with respect to the tip of the needle electrode for a particular discharge power led to a more than fourfold increase in the concentration of ozone produced by the discharge and also, for a constant airflow, the ozone production yield.

Dense mesh sampling for video-based facial animation

NASA Astrophysics Data System (ADS)

Peszor, Damian; Wojciechowska, Marzena

2016-06-01

The paper describes an approach for selection of feature points on three-dimensional, triangle mesh obtained using various techniques from several video footages. This approach has a dual purpose. First, it allows to minimize the data stored for the purpose of facial animation, so that instead of storing position of each vertex in each frame, one could store only a small subset of vertices for each frame and calculate positions of others based on the subset. Second purpose is to select feature points that could be used for anthropometry-based retargeting of recorded mimicry to another model, with sampling density beyond that which can be achieved using marker-based performance capture techniques. Developed approach was successfully tested on artificial models, models constructed using structured light scanner, and models constructed from video footages using stereophotogrammetry.

Emerging CFD technologies and aerospace vehicle design

NASA Technical Reports Server (NTRS)

Aftosmis, Michael J.

1995-01-01

With the recent focus on the needs of design and applications CFD, research groups have begun to address the traditional bottlenecks of grid generation and surface modeling. Now, a host of emerging technologies promise to shortcut or dramatically simplify the simulation process. This paper discusses the current status of these emerging technologies. It will argue that some tools are already available which can have positive impact on portions of the design cycle. However, in most cases, these tools need to be integrated into specific engineering systems and process cycles to be used effectively. The rapidly maturing status of unstructured and Cartesian approaches for inviscid simulations makes suggests the possibility of highly automated Euler-boundary layer simulations with application to loads estimation and even preliminary design. Similarly, technology is available to link block structured mesh generation algorithms with topology libraries to avoid tedious re-meshing of topologically similar configurations. Work in algorithmic based auto-blocking suggests that domain decomposition and point placement operations in multi-block mesh generation may be properly posed as problems in Computational Geometry, and following this approach may lead to robust algorithmic processes for automatic mesh generation.

A simple finite element method for non-divergence form elliptic equation

DOE PAGES

Mu, Lin; Ye, Xiu

2017-03-01

Here, we develop a simple finite element method for solving second order elliptic equations in non-divergence form by combining least squares concept with discontinuous approximations. This simple method has a symmetric and positive definite system and can be easily analyzed and implemented. We could have also used general meshes with polytopal element and hanging node in the method. We prove that our finite element solution approaches to the true solution when the mesh size approaches to zero. Numerical examples are tested that demonstrate the robustness and flexibility of the method.

A simple finite element method for non-divergence form elliptic equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Lin; Ye, Xiu

Here, we develop a simple finite element method for solving second order elliptic equations in non-divergence form by combining least squares concept with discontinuous approximations. This simple method has a symmetric and positive definite system and can be easily analyzed and implemented. We could have also used general meshes with polytopal element and hanging node in the method. We prove that our finite element solution approaches to the true solution when the mesh size approaches to zero. Numerical examples are tested that demonstrate the robustness and flexibility of the method.

Report of the sensor readout electronics panel

NASA Technical Reports Server (NTRS)

Fossum, Eric R.; Carson, J.; Kleinhans, W.; Kosonocky, W.; Kozlowski, L.; Pecsalski, A.; Silver, A.; Spieler, H.; Woolaway, J.

1991-01-01

The findings of the Sensor Readout Electronics Panel are summarized in regard to technology assessment and recommended development plans. In addition to two specific readout issues, cryogenic readouts and sub-electron noise, the panel considered three advanced technology areas that impact the ability to achieve large format sensor arrays. These are mega-pixel focal plane packaging issues, focal plane to data processing module interfaces, and event driven readout architectures. Development in each of these five areas was judged to have significant impact in enabling the sensor performance desired for the Astrotech 21 mission set. Other readout issues, such as focal plane signal processing or other high volume data acquisition applications important for Eos-type mapping, were determined not to be relevant for astrophysics science goals.

Performance simulation of BaBar DIRC bar boxes in TORCH

NASA Astrophysics Data System (ADS)

Föhl, K.; Brook, N.; Castillo García, L.; Cussans, D.; Forty, R.; Frei, C.; Gao, R.; Gys, T.; Harnew, N.; Piedigrossi, D.; Rademacker, J.; Ros García, A.; van Dijk, M.

2017-12-01

TORCH is a large-area precision time-of-flight detector based on the DIRC principle. The DIRC bar boxes of the BaBar experiment at SLAC could possibly be reused to form a part of the TORCH detector time-of-flight wall area, proposed to provide positive particle identification of low momentum kaons in the LHCb experiment at CERN. For a potential integration of BaBar bar boxes into TORCH, new imaging readout optics are required. From the several designs of readout optics that have been considered, two are used in this paper to study the effect of BaBar bar optical imperfections on the detector reconstruction performance. The kaon-pion separation powers obtained from analysing simulated photon hit patterns show the performance reduction for a BaBar bar of non-square geometry compared to a perfectly rectangular cross section.

Compact multiwire proportional counters for the detection of fission fragments

NASA Astrophysics Data System (ADS)

Jhingan, Akhil; Sugathan, P.; Golda, K. S.; Singh, R. P.; Varughese, T.; Singh, Hardev; Behera, B. R.; Mandal, S. K.

2009-12-01

Two large area multistep position sensitive (two dimensional) multiwire proportional counters have been developed for experiments involving study of fission dynamics using general purpose scattering chamber facility at IUAC. Both detectors have an active area of 20×10 cm2 and provide position signals in horizontal (X) and vertical (Y) planes, timing signal for time of flight measurements and energy signal giving the differential energy loss in the active volume. The design features are optimized for the detection of low energy heavy ions at very low gas pressures. Special care was taken in setting up the readout electronics, constant fraction discriminators for position signals in particular, to get optimum position and timing resolutions along with high count rate handling capability of low energy heavy ions. A custom made charge sensitive preamplifier, having lower gain and shorter decay time, has been developed for extracting the differential energy loss signal. The position and time resolutions of the detectors were determined to be 1.1 mm full width at half maximum (FWHM) and 1.7 ns FWHM, respectively. The detector could handle heavy ion count rates exceeding 20 kHz without any breakdown. Time of flight signal in combination with differential energy loss signal gives a clean separation of fission fragments from projectile and target like particles. The timing and position signals of the detectors are used for fission coincidence measurements and subsequent extraction of their mass, angular, and total kinetic energy distributions. This article describes systematic study of these fission counters in terms of efficiency, time resolution, count rate handling capability, position resolution, and the readout electronics. The detector has been operated with both five electrode geometry and four electrode geometry, and a comparison has been made in their performances.

In Vitro Comparison of a Vibrating Mesh Nebulizer Operating in Inspiratory Synchronized and Continuous Nebulization Modes During Noninvasive Ventilation.

PubMed

Michotte, Jean-Bernard; Staderini, Enrico; Le Pennec, Deborah; Dugernier, Jonathan; Rusu, Rares; Roeseler, Jean; Vecellio, Laurent; Liistro, Giuseppe; Reychler, Grégory

2016-08-01

Backround: Coupling nebulization with noninvasive ventilation (NIV) has been shown to be effective in patients with respiratory diseases. However, a breath-synchronized nebulization option that could potentially improve drug delivery by limiting drug loss during exhalation is currently not available on bilevel ventilators. The aim of this in vitro study was to compare aerosol delivery of amikacin with a vibrating mesh nebulizer coupled to a single-limb circuit bilevel ventilator, using conventional continuous (Conti-Neb) and experimental inspiratory synchronized (Inspi-Neb) nebulization modes. Using an adult lung bench model of NIV, we tested a vibrating mesh device coupled with a bilevel ventilator in both nebulization modes. Inspi-Neb delivered aerosol only during the whole inspiratory phase, whereas Conti-Neb delivered aerosol continuously. The nebulizer was charged with amikacin solution (250 mg/3 mL) and placed at two different positions: between the lung and exhalation port and between the ventilator and exhalation port. Inhaled, expiratory wasted and circuit lost doses were assessed by residual gravimetric method. Particle size distribution of aerosol delivered at the outlet of the ventilator circuit during both nebulization modes was measured by laser diffraction method. Regardless of the nebulizer position, Inspi-Neb produced higher inhaled dose (p < 0.01; +6.3% to +16.8% of the nominal dose), lower expiratory wasted dose (p < 0.05; -2.7% to -42.6% of the nominal dose), and greater respirable dose (p < 0.01; +8.4% to +15.2% of the nominal dose) than Conti-Neb. The highest respirable dose was found with the nebulizer placed between the lung and exhalation port (48.7% ± 0.3% of the nominal dose). During simulated NIV with a single-limb circuit bilevel ventilator, the use of inspiratory synchronized vibrating mesh nebulization improves respirable dose and reduces drug loss of amikacin compared with continuous vibrating mesh nebulization.

FASH and MASH: female and male adult human phantoms based on polygon mesh surfaces: I. Development of the anatomy

NASA Astrophysics Data System (ADS)

Cassola, V. F.; de Melo Lima, V. J.; Kramer, R.; Khoury, H. J.

2010-01-01

Among computational models, voxel phantoms based on computer tomographic (CT), nuclear magnetic resonance (NMR) or colour photographic images of patients, volunteers or cadavers have become popular in recent years. Although being true to nature representations of scanned individuals, voxel phantoms have limitations, especially when walled organs have to be segmented or when volumes of organs or body tissues, like adipose, have to be changed. Additionally, the scanning of patients or volunteers is usually made in supine position, which causes a shift of internal organs towards the ribcage, a compression of the lungs and a reduction of the sagittal diameter especially in the abdominal region compared to the regular anatomy of a person in the upright position, which in turn can influence organ and tissue absorbed or equivalent dose estimates. This study applies tools developed recently in the areas of computer graphics and animated films to the creation and modelling of 3D human organs, tissues, skeletons and bodies based on polygon mesh surfaces. Female and male adult human phantoms, called FASH (Female Adult meSH) and MASH (Male Adult meSH), have been designed using software, such as MakeHuman, Blender, Binvox and ImageJ, based on anatomical atlases, observing at the same time organ masses recommended by the International Commission on Radiological Protection for the male and female reference adult in report no 89. 113 organs, bones and tissues have been modelled in the FASH and the MASH phantoms representing locations for adults in standing posture. Most organ and tissue masses of the voxelized versions agree with corresponding data from ICRP89 within a margin of 2.6%. Comparison with the mesh-based male RPI_AM and female RPI_AF phantoms shows differences with respect to the material used, to the software and concepts applied, and to the anatomies created.

Sexual function before and 1 year after laparoscopic sacrocolpopexy.

PubMed

Salamon, Charbel G; Lewis, Christa M; Priestley, Jennifer; Culligan, Patrick J

2014-01-01

This study aimed to compare sexual function before and 1 year after laparoscopic sacrocolpopexy using a porcine dermis or a polypropylene mesh material. This was a secondary analysis of sexual function measured before and 1 year after laparoscopic sacrocolpopexy in a group of 81 sexually active women participating in a randomized controlled trial comparing porcine dermis and polypropylene mesh. Sexual function was assessed using the short form of the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12). Responses to individual questions from the physical domain of the PISQ-12 were also analyzed. Additional information included the type of mesh material used and whether a concomitant suburethral sling or perineorrhaphy was performed. There was a significant postoperative improvement in total PISQ-12 scores for the entire cohort (33.2 vs 38.3, P < 0.01). Similarly, PISQ-12 scores were significantly improved in both groups (33.2 preoperative vs 37.4 one year postoperative in the porcine dermis, P < 0.01 and 33.2 vs 39.2 in the polypropylene mesh, P < 0.01). There were no differences between the 2 graft material groups. Preoperatively, 63.0% (48/76) of women reported avoiding sexual intercourse because of bulging in vagina (PISQ12-question #8), at 1 year postoperatively only 4% (3/76) had a positive response (P < 0.01). We observed a significant decrease in the number of women who reported pain during intercourse at 12 months as evidenced by the responses to the PISQ12-question #5, 47.4% (36/76) versus 26.3% (20/76) (P < 0.01). The addition of a suburethral sling or a perineorrhaphy did not negatively impact sexual function at 1 year. Laparoscopic sacrocolpopexy had a positive impact on sexual function at 1 year regardless of whether a porcine dermis or a polypropylene mesh material was used.

Feasibility study using MRI and two optical CT scanners for readout of polymer gel and PresageTM

NASA Astrophysics Data System (ADS)

Svensson, H.; Skyt, P. S.; Ceberg, S.; Doran, S.; Muren, L. P.; Balling, P.; Petersen, J. B. B.; Bäck, S. Å. J.

2013-06-01

The aim of this study was to compare the conventional combination of three-dimensional dosimeter (nPAG gel) and readout method (MRI) with other combinations of three-dimensional dosimeters (nPAG gel/PresageTM) and readout methods (optical CT scanners). In the first experiment, the dose readout of a gel irradiated with a four field-box technique was performed with both an Octopus IQ scanner and MRI. It was seen that the MRI readout agreed slightly better to the TPS. In another experiment, a gel and a PresageTM sample were irradiated with a VMAT field and read out using MRI and a fast laser scanner, respectively. A comparison between the TPS and the volumes revealed that the MRI/gel readout had closer resemblance to the TPS than the optical CT/PresageTM readout. There are clearly potential in the evaluated optical CT scanners, but more time has to be invested in the particular scanning scenario than was possible in this study.

A pixelated charge readout for Liquid Argon Time Projection Chambers

NASA Astrophysics Data System (ADS)

Asaadi, J.; Auger, M.; Ereditato, A.; Goeldi, D.; Hänni, R.; Kose, U.; Kreslo, I.; Lorca, D.; Luethi, M.; von Rohr, C. Rudolf; Sinclair, J.; Stocker, F.; Tognina, C.; Weber, M.

2018-02-01

Liquid Argon Time Projection Chambers (LArTPCs) are ideally suited to perform long-baseline neutrino experiments aiming to measure CP violation in the lepton sector, and determine the ordering of the three neutrino mass eigenstates. LArTPCs have used projective wire readouts for charge detection since their conception in 1977. However, wire readouts are notoriously fragile and therefore a limiting factor in the design of any large mass detectors. Furthermore, a wire readout also introduces intrinsic ambiguities in event reconstruction. Within the ArgonCube concept—the liquid argon component of the DUNE near detector—we are developing a pixelated charge readout for LArTPCs. Pixelated charge readout systems represent the single largest advancement in the sensitivity of LArTPCs. They are mechanically robust and provide direct 3D readout, serving to minimise reconstruction ambiguities, enabling more advanced triggers, further reducing event pile-up and improving background rejection. This article presents first results from a pixelated LArTPC prototype built and operated in Bern.

Development of a large area microstructure photomultiplier assembly (LAMPA)

NASA Astrophysics Data System (ADS)

Clifford, E. T. H.; Dick, M.; Facina, M.; Wakeford, D.; Andrews, H. R.; Ing, H.; Best, D.; Baginski, M. J.

2017-05-01

Large area (> m2) position-sensitive readout of scintillators is important for passive/active gamma and neutron imaging for counter-terrorism applications. The goal of the LAMPA project is to provide a novel, affordable, large-area photodetector (8" x 8") by replacing the conventional dynodes of photomultiplier tubes (PMTs) with electron multiplier microstructure boards (MSBs) that can be produced using industrial manufacturing techniques. The square, planar format of the LAMPA assemblies enables tiling of multiple units to support large area applications. The LAMPA performance objectives include comparable gain, noise, timing, and energy resolution relative to conventional PMTs, as well as spatial resolution in the few mm range. The current LAMPA prototype is a stack of 8" x 8" MSBs made commercially by chemical etching of a molybdenum substrate and coated with hydrogen-terminated boron-doped diamond for high secondary emission yield (SEY). The layers of MSBs are electrically isolated using ceramic standoffs. Field-shaping grids are located between adjacent boards to achieve good transmission of electrons from one board to the next. The spacing between layers and the design of the microstructure pattern and grids were guided by simulations performed using an electro-optics code. A position sensitive anode board at the back of the stack of MSBs provides 2-D readout. This presentation discusses the trade studies performed in the design of the MSBs, the measurements of SEY from various electro-emissive materials, the electro-optics simulations conducted, the design of the 2-D readout, and the mechanical aspects of the LAMPA design, in order to achieve a gain of > 104 in an 8-stage stack of MSBs, suitable for use with various scintillators when coupled to an appropriate photocathode.

A High Resolution Monolithic Crystal, DOI, MR Compatible, PET Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robert S Miyaoka

The principle objective of this proposal is to develop a positron emission tomography (PET) detector with depth-of-interaction (DOI) positioning capability that will achieve state of the art spatial resolution and sensitivity performance for small animal PET imaging. When arranged in a ring or box detector geometry, the proposed detector module will support <1 mm3 image resolution and >15% absolute detection efficiency. The detector will also be compatible with operation in a MR scanner to support simultaneous multi-modality imaging. The detector design will utilize a thick, monolithic crystal scintillator readout by a two-dimensional array of silicon photomultiplier (SiPM) devices using amore » novel sensor on the entrance surface (SES) design. Our hypothesis is that our single-ended readout SES design will provide an effective DOI positioning performance equivalent to more expensive dual-ended readout techniques and at a significantly lower cost. Our monolithic crystal design will also lead to a significantly lower cost system. It is our goal to design a detector with state of the art performance but at a price point that is affordable so the technology can be disseminated to many laboratories. A second hypothesis is that using SiPM arrays, the detector will be able to operate in a MR scanner without any degradation in performance to support simultaneous PET/MR imaging. Having a co-registered MR image will assist in radiotracer localization and may also be used for partial volume corrections to improve radiotracer uptake quantitation. The far reaching goal of this research is to develop technology for medical research that will lead to improvements in human health care.« less

The Effectiveness of Shrouding on Reducing Meshed Spur Gear Power Loss - Test Results

NASA Technical Reports Server (NTRS)

Delgado, I. R.; Hurrell, M. J.

2017-01-01

Gearbox efficiency is reduced at high rotational speeds due to windage drag and viscous effects on rotating, meshed gear components. A goal of NASA aeronautics rotorcraft research is aimed at propulsion technologies that improve efficiency while minimizing vehicle weight. Specifically, reducing power losses to rotorcraft gearboxes would allow gains in areas such as vehicle payload, range, mission type, and fuel consumption. To that end, a gear windage rig has been commissioned at NASA Glenn Research Center to measure windage drag on gears and to test methodologies to mitigate windage power losses. One method used in rotorcraft gearbox design attempts to reduce gear windage power loss by utilizing close clearance walls to enclose the gears in both the axial and radial directions. The close clearance shrouds result in reduced drag on the gear teeth, and reduced power loss. For meshed spur gears, the shrouding takes the form of metal side plates and circumferential metal sectors. Variably positioned axial and radial shrouds are incorporated in the NASA rig to study the effect of shroud clearance on gearbox power loss. A number of researchers have given experimental and analytical results for single spur gears, with and without shrouding. Shrouded meshed spur gear test results are sparse in the literature. Windage tests were run at NASA Glenn using meshed spur gears at four shroud configurations: unshrouded, shrouded (max. axial, max radial), and two intermediate shrouding conditions. Results are compared to available meshed spur gear power loss data analyses as well as single spur gear data/analyses. Recommendations are made for future work.

The Effectiveness of Shrouding on Reducing Meshed Spur Gear Power Loss Test Results

NASA Technical Reports Server (NTRS)

Delgado, I. R.; Hurrell, M. J.

2017-01-01

Gearbox efficiency is reduced at high rotational speeds due to windage drag and viscous effects on rotating, meshed gear components. A goal of NASA aeronautics rotorcraft research is aimed at propulsion technologies that improve efficiency while minimizing vehicle weight. Specifically, reducing power losses to rotorcraft gearboxes would allow gains in areas such as vehicle payload, range, mission type, and fuel consumption. To that end, a gear windage rig has been commissioned at NASA Glenn Research Center to measure windage drag on gears and to test methodologies to mitigate windage power losses. One method used in rotorcraft gearbox design attempts to reduce gear windage power loss by utilizing close clearance walls to enclose the gears in both the axial and radial directions. The close clearance shrouds result in reduced drag on the gear teeth and reduced power loss. For meshed spur gears, the shrouding takes the form of metal side plates and circumferential metal sectors. Variably positioned axial and radial shrouds are incorporated in the NASA rig to study the effect of shroud clearance on gearbox power loss. A number of researchers have given experimental and analytical results for single spur gears, with and without shrouding. Shrouded meshed spur gear test results are sparse in the literature. Windage tests were run at NASA Glenn using meshed spur gears at four shroud configurations: unshrouded, shrouded (max. axial, max. radial), and two intermediate shrouding conditions. Results are compared to available meshed spur gear power loss data analyses as well as single spur gear data analyses.

Using virtual ridge augmentation and 3D printing to fabricate a titanium mesh positioning device: A novel technique letter.

PubMed

Al-Ardah, Aladdin; Alqahtani, Nasser; AlHelal, Abdulaziz; Goodacre, Brian; Swamidass, Rajesh; Garbacea, Antoanela; Lozada, Jaime

2018-05-02

This technique describes a novel approach for planning and augmenting a large bony defect using a titanium mesh (TiMe). A 3-dimensional (3D) surgical model was virtually created from a cone beam computed tomography (CBCT) and wax-pattern of the final prosthetic outcome. The required bone volume (horizontally and vertically) was digitally augmented and then 3D printed to create a bone model. The 3D model was then used to contour the TiMe in accordance with the digital augmentation. With the contoured / preformed TiMe on the 3D printed model a positioning jig was made to aid the placement of the TiMe as planned during surgery. Although this technique does not impact the final outcome of the augmentation procedure, it allows the clinician to virtually design the augmentation, preform and contour the TiMe, and create a positioning jig reducing surgical time and error.

Silicon oxynitride-on-glass waveguide array refractometer with wide sensing range and integrated read-out (Conference Presentation)

NASA Astrophysics Data System (ADS)

Viegas, Jaime; Mayeh, Mona; Srinivasan, Pradeep; Johnson, Eric G.; Marques, Paulo V. S.; Farahi, Faramarz

2017-02-01

In this work, a silicon oxynitride-on-silica refractometer is presented, based on sub-wavelength coupled arrayed waveguide interference, and capable of low-cost, high resolution, large scale deployment. The sensor has an experimental spectral sensitivity as high as 3200 nm/RIU, covering refractive indices ranging from 1 (air) up to 1.43 (oils). The sensor readout can be performed by standard spectrometers techniques of by pattern projection onto a camera, followed by optical pattern recognition. Positive identification of the refractive index of an unknown species is obtained by pattern cross-correlation with a look-up calibration table based algorithm. Given the lower contrast between core and cladding in such devices, higher mode overlap with single mode fiber is achieved, leading to a larger coupling efficiency and more relaxed alignment requirements as compared to silicon photonics platform. Also, the optical transparency of the sensor in the visible range allows the operation with light sources and camera detectors in the visible range, of much lower capital costs for a complete sensor system. Furthermore, the choice of refractive indices of core and cladding in the sensor head with integrated readout, allows the fabrication of the same device in polymers, for mass-production replication of disposable sensors.

Sequence-dependent DNA deformability studied using molecular dynamics simulations.

PubMed

Fujii, Satoshi; Kono, Hidetoshi; Takenaka, Shigeori; Go, Nobuhiro; Sarai, Akinori

2007-01-01

Proteins recognize specific DNA sequences not only through direct contact between amino acids and bases, but also indirectly based on the sequence-dependent conformation and deformability of the DNA (indirect readout). We used molecular dynamics simulations to analyze the sequence-dependent DNA conformations of all 136 possible tetrameric sequences sandwiched between CGCG sequences. The deformability of dimeric steps obtained by the simulations is consistent with that by the crystal structures. The simulation results further showed that the conformation and deformability of the tetramers can highly depend on the flanking base pairs. The conformations of xATx tetramers show the most rigidity and are not affected by the flanking base pairs and the xYRx show by contrast the greatest flexibility and change their conformations depending on the base pairs at both ends, suggesting tetramers with the same central dimer can show different deformabilities. These results suggest that analysis of dimeric steps alone may overlook some conformational features of DNA and provide insight into the mechanism of indirect readout during protein-DNA recognition. Moreover, the sequence dependence of DNA conformation and deformability may be used to estimate the contribution of indirect readout to the specificity of protein-DNA recognition as well as nucleosome positioning and large-scale behavior of nucleic acids.

The XGS instrument on-board THESEUS

NASA Astrophysics Data System (ADS)

Fuschino, F.; Campana, R.; Labanti, C.; Marisaldi, M.; Amati, L.; Fiorini, M.; Uslenghi, M.; Baldazzi, G.; Evangelista, Y.; Elmi, I.; Feroci, M.; Frontera, F.; Rachevski, A.; Rignanese, L. P.; Vacchi, A.; Zampa, G.; Zampa, N.; Rashevskaya, I.; Bellutti, P.; Piemonte, C.

2016-10-01

Consolidated techniques used for space-borne X-ray and gamma-ray instruments are based on the use of scintillators coupled to Silicon photo-detectors. This technology associated with modern very low noise read-out electronics allows the design of innovative architectures able to reduce drastically the system complexity and power consumption, also with a moderate-to-high number of channels. These detector architectures can be exploited in the design of space instrumentation for gamma-spectroscopy with the benefit of possible smart background rejection strategies. We describe a detector prototype with 3D imaging capabilities to be employed in future gamma-ray and particle space missions in the 0.002-100 MeV energy range. The instrument is based on a stack of scintillating bars read out by Silicon Drift Detectors (SDDs) at both ends. The spatial segmentation and the crystal double-side readout allow a 3D position reconstruction with ∼3 mm accuracy within the full active volume, using a 2D readout along the two external faces of the detector. Furthermore, one of the side of SDDs can be used simultaneously to detect X-rays in the 2-30 keV energy range. The characteristics of this instrument make it suitable in next generation gamma-ray and particle space missions for Earth or outer space observations, and it will be briefly illustrated.

Monitoring the Deterioration of Stone at Mindener MUSEUM'S Lapidarium

NASA Astrophysics Data System (ADS)

Pomaska, G.

2013-07-01

Mindener Museum's Lapidarium incorporates a collection of stone work like reliefs, sculptures and inscriptions from different time epochs as advices of the city's history. These gems must be protected against environmental influences and deterioration. In advance of the measures a 3D reconstruction and detailed documentation has to be taken. The framework to establish hard- and software must match the museum's infrastructure. Two major question will be answered. Are low-cost scanning devices like depth cameras and digital of the shelf cameras suitable for the data acquisition? Does the functionality of open source and freeware covers the demand on investigation and analysis in this application? The working chain described in this contribution covers the structure from motion method and the reconstruction with RGB-D cameras. Mesh processing such as cleaning, smoothing, poisson surface reconstruction and texturing will be accomplished with MeshLab. Data acquisition and modelling continues in structure analysis. Therefore the focus lies as well on latest software developments related to 3D printing technologies. Repairing and finishing of meshes is a task for MeshMixer. Netfabb as a tool for positioning, dimensioning and slicing enables virtual handling of the items. On the Sketchfab web site one can publish and share 3D objects with integration into web pages supported by WebGL. Finally if a prototype is needed, the mesh can be uploaded to a 3D printing device provided by an online service.

Clinical observation of a modified surgical method: posterior vaginal mesh suspension of female rectocele with intractable constipation.

PubMed

Hong, Ling; Li, Huai-Fang; Sun, Jing; Zhu, Jian-Long; Ai, Gui-hai; Li, Li; Zhang, Bo; Chi, Feng-li; Tong, Xiao-Wen

2012-01-01

To explore the feasibility and effectiveness of a modified posterior vaginal mesh suspension method in treating female rectocele with intractable constipation. Descriptive study (Canadian Task Force classification II-3). The study was performed in the Study Center for Female Pelvic Dysfunction Disease, Department of Obstetrics and Gynecology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China. The Study Center includes 15 physicians, most of whom have received advanced training in pelvic floor dysfunctional disease and can skillfully perform many types of operations in patients with such disease. Almost 1500 operations to treat pelvic floor dysfunctional disease are performed every year at the center. Thirty-six women with rectocele with intractable constipation. Posterior vaginal mesh suspension. All patients were followed up for 15 to 36 months. In 29 patients, the condition was cured completely; in 5 patients it had improved; and in 2 patients, the intervention had no effect. Insofar as recovery and improved results, the overall effectiveness rate was 94.4%. Posterior vaginal mesh suspension is an effective, harmless, and convenient method for treatment of female rectocele with intractable constipation. It has positive short-term curative effects, with few complications and sequelae. However, the long-term effects of posterior vaginal mesh suspension should be evaluated. Copyright © 2012 AAGL. Published by Elsevier Inc. All rights reserved.

Development of a hip joint model for finite volume simulations.

PubMed

Cardiff, P; Karač, A; FitzPatrick, D; Ivanković, A

2014-01-01

This paper establishes a procedure for numerical analysis of a hip joint using the finite volume method. Patient-specific hip joint geometry is segmented directly from computed tomography and magnetic resonance imaging datasets and the resulting bone surfaces are processed into a form suitable for volume meshing. A high resolution continuum tetrahedral mesh has been generated, where a sandwich model approach is adopted; the bones are represented as a stiffer cortical shells surrounding more flexible cancellous cores. Cartilage is included as a uniform thickness extruded layer and the effect of layer thickness is investigated. To realistically position the bones, gait analysis has been performed giving the 3D positions of the bones for the full gait cycle. Three phases of the gait cycle are examined using a finite volume based custom structural contact solver implemented in open-source software OpenFOAM.

An optical fiber-based flexible readout system for micro-pattern gas detectors

NASA Astrophysics Data System (ADS)

Li, C.; Feng, C. Q.; Zhu, D. Y.; Liu, S. B.; An, Q.

2018-04-01

This paper presents an optical fiber-based readout system that is intended to provide a general purpose multi-channel readout solution for various Micro-Pattern Gas Detectors (MPGDs). The proposed readout system is composed of several front-end cards (FECs) and a data collection module (DCM). The FEC exploits the capability of an existing 64-channel generic TPC readout ASIC chip, named AGET, to implement 256 channels readout. AGET offers FEC a large flexibility in gain range (4 options from 120 fC to 10 pC), peaking time (16 options from 50 ns to 1 us) and sampling freqency (100 MHz max.). The DCM contains multiple 1 Gbps optical fiber serial link interfaces that allow the system scaling up to 1536 channels with 6 FECs and 1 DCM. Further scaling up is possible through cascading of multiple DCMs, by configuring one DCM as a master while other DCMs in slave mode. This design offers a rapid readout solution for different application senario. Tests indicate that the nonlinearity of each channel is less than 1%, and the equivalent input noise charge is typically around 0.7 fC in RMS (root mean square), with a noise slope of about 0.01 fC/pF. The system level trigger rate limit is about 700 Hz in all channel readout mode. When in hit channel readout mode, supposing that typically 10 percent of channels are fired, trigger rate can go up to about 7 kHz. This system has been tested with Micromegas detector and GEM detector, confirming its capability in MPGD readout. Details of hardware and FPGA firmware design, as well as system performances, are described in the paper.

Simulation of stochastic diffusion via first exit times

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lötstedt, Per, E-mail: perl@it.uu.se; Meinecke, Lina, E-mail: lina.meinecke@it.uu.se

2015-11-01

In molecular biology it is of interest to simulate diffusion stochastically. In the mesoscopic model we partition a biological cell into unstructured subvolumes. In each subvolume the number of molecules is recorded at each time step and molecules can jump between neighboring subvolumes to model diffusion. The jump rates can be computed by discretizing the diffusion equation on that unstructured mesh. If the mesh is of poor quality, due to a complicated cell geometry, standard discretization methods can generate negative jump coefficients, which no longer allows the interpretation as the probability to jump between the subvolumes. We propose a methodmore » based on the mean first exit time of a molecule from a subvolume, which guarantees positive jump coefficients. Two approaches to exit times, a global and a local one, are presented and tested in simulations on meshes of different quality in two and three dimensions.« less

A multi-purpose method for analysis of spur gear tooth loading

NASA Technical Reports Server (NTRS)

Kasuba, R.; Evans, J. W.; August, R.; Frater, J. L.

1981-01-01

A large digitized approach was developed for the static and dynamic load analysis of spur gearing. An iterative procedure was used to calculate directly the "variable-variable" gear mesh stiffness as a function of transmitted load, gear tooth profile errors, gear tooth deflections and gear hub torsional deformation, and position of contacting profile points. The developed approach can be used to analyze the loads, Hertz stresses, and PV for the normal and high contrast ratio gearing, presently the modeling is limited to the condition that for a given gear all teeth have identical spacing and profiles (with or without surface imperfections). Certain types of simulated sinusoidal profile errors and pitting can cause interruptions of the gear mesh stiffness function and, thus, increase the dynamic loads in spur gearing. In addition, a finite element stress and mesh subprogram was developed for future introduction into the main program for calculating the gear tooth bending stresses under dynamic loads.

Simulation of stochastic diffusion via first exit times

PubMed Central

Lötstedt, Per; Meinecke, Lina

2015-01-01

In molecular biology it is of interest to simulate diffusion stochastically. In the mesoscopic model we partition a biological cell into unstructured subvolumes. In each subvolume the number of molecules is recorded at each time step and molecules can jump between neighboring subvolumes to model diffusion. The jump rates can be computed by discretizing the diffusion equation on that unstructured mesh. If the mesh is of poor quality, due to a complicated cell geometry, standard discretization methods can generate negative jump coefficients, which no longer allows the interpretation as the probability to jump between the subvolumes. We propose a method based on the mean first exit time of a molecule from a subvolume, which guarantees positive jump coefficients. Two approaches to exit times, a global and a local one, are presented and tested in simulations on meshes of different quality in two and three dimensions. PMID:26600600

The lowest-order weak Galerkin finite element method for the Darcy equation on quadrilateral and hybrid meshes

NASA Astrophysics Data System (ADS)

Liu, Jiangguo; Tavener, Simon; Wang, Zhuoran

2018-04-01

This paper investigates the lowest-order weak Galerkin finite element method for solving the Darcy equation on quadrilateral and hybrid meshes consisting of quadrilaterals and triangles. In this approach, the pressure is approximated by constants in element interiors and on edges. The discrete weak gradients of these constant basis functions are specified in local Raviart-Thomas spaces, specifically RT0 for triangles and unmapped RT[0] for quadrilaterals. These discrete weak gradients are used to approximate the classical gradient when solving the Darcy equation. The method produces continuous normal fluxes and is locally mass-conservative, regardless of mesh quality, and has optimal order convergence in pressure, velocity, and normal flux, when the quadrilaterals are asymptotically parallelograms. Implementation is straightforward and results in symmetric positive-definite discrete linear systems. We present numerical experiments and comparisons with other existing methods.

Low-power priority Address-Encoder and Reset-Decoder data-driven readout for Monolithic Active Pixel Sensors for tracker system

NASA Astrophysics Data System (ADS)

Yang, P.; Aglieri, G.; Cavicchioli, C.; Chalmet, P. L.; Chanlek, N.; Collu, A.; Gao, C.; Hillemanns, H.; Junique, A.; Kofarago, M.; Keil, M.; Kugathasan, T.; Kim, D.; Kim, J.; Lattuca, A.; Marin Tobon, C. A.; Marras, D.; Mager, M.; Martinengo, P.; Mazza, G.; Mugnier, H.; Musa, L.; Puggioni, C.; Rousset, J.; Reidt, F.; Riedler, P.; Snoeys, W.; Siddhanta, S.; Usai, G.; van Hoorne, J. W.; Yi, J.

2015-06-01

Active Pixel Sensors used in High Energy Particle Physics require low power consumption to reduce the detector material budget, low integration time to reduce the possibilities of pile-up and fast readout to improve the detector data capability. To satisfy these requirements, a novel Address-Encoder and Reset-Decoder (AERD) asynchronous circuit for a fast readout of a pixel matrix has been developed. The AERD data-driven readout architecture operates the address encoding and reset decoding based on an arbitration tree, and allows us to readout only the hit pixels. Compared to the traditional readout structure of the rolling shutter scheme in Monolithic Active Pixel Sensors (MAPS), AERD can achieve a low readout time and a low power consumption especially for low hit occupancies. The readout is controlled at the chip periphery with a signal synchronous with the clock, allows a good digital and analogue signal separation in the matrix and a reduction of the power consumption. The AERD circuit has been implemented in the TowerJazz 180 nm CMOS Imaging Sensor (CIS) process with full complementary CMOS logic in the pixel. It works at 10 MHz with a matrix height of 15 mm. The energy consumed to read out one pixel is around 72 pJ. A scheme to boost the readout speed to 40 MHz is also discussed. The sensor chip equipped with AERD has been produced and characterised. Test results including electrical beam measurement are presented.

Optically Addressable, Ferroelectric Memory With NDRO

NASA Technical Reports Server (NTRS)

Thakoor, Sarita

1994-01-01

For readout, memory cells addressed via on-chip semiconductor lasers. Proposed thin-film ferroelectric memory device features nonvolatile storage, optically addressable, nondestructive readout (NDRO) with fast access, and low vulnerability to damage by ionizing radiation. Polarization switched during recording and erasure, but not during readout. As result, readout would not destroy contents of memory, and operating life in specific "read-intensive" applications increased up to estimated 10 to the 16th power cycles.

A multiball read-out for the spherical proportional counter

NASA Astrophysics Data System (ADS)

Giganon, A.; Giomataris, I.; Gros, M.; Katsioulas, I.; Navick, X. F.; Tsiledakis, G.; Savvidis, I.; Dastgheibi-Fard, A.; Brossard, A.

2017-12-01

We present a novel concept of proportional gas amplification for the read-out of the spherical proportional counter. The standard single-ball read-out presents limitations for large diameter spherical detectors and high-pressure operations. We have developed a multi-ball read-out system which consists of several balls placed at a fixed distance from the center of the spherical vessel. Such a module can tune the volume electric field at the desired value and can also provide detector segmentation with individual ball read-out. In the latter case, the large volume of the vessel becomes a spherical time projection chamber with 3D capabilities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rebay, S.

This work is devoted to the description of an efficient unstructured mesh generation method entirely based on the Delaunay triangulation. The distinctive characteristic of the proposed method is that point positions and connections are computed simultaneously. This result is achieved by taking advantage of the sequential way in which the Bowyer-Watson algorithm computes the Delaunay triangulation. Two methods are proposed which have great geometrical flexibility, in that they allow us to treat domains of arbitrary shape and topology and to generate arbitrarily nonuniform meshes. The methods are computationally efficient and are applicable both in two and three dimensions. 11 refs.,more » 20 figs., 1 tab.« less

Defect images by planar ECT probe of meander-mesh coils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamada, Sotoshi; Katou, Masaki; Iwahara, Masayoshi

1996-09-01

This paper presents results pertaining to image data obtained from a planar meander-mesh coupled coil type ECT probe. The image data makes it possible to detect not only the existence of a defect but also to extract detailed information regarding the nature of the defect, such as its position, shape, length, and direction. In order to recognize a defect distinctly, the authors have fabricated the high sensitive planar coil which can be used to image a 2-D representation of the ECT signal. The relationships between the image pattern and defect shape are discussed.

Accounting for Dark Current Accumulated during Readout of Hubble's ACS/WFC Detectors

NASA Astrophysics Data System (ADS)

Ryon, Jenna E.; Grogin, Norman A.; Coe, Dan A.; ACS Team

2018-06-01

We investigate the properties of excess dark current accumulated during the 100-second full-frame readout of the Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) detectors. This excess dark current, called "readout dark", gives rise to ambient background gradients and hot columns in each ACS/WFC image. While readout dark signal is removed from science images during the bias correction step in CALACS, the additional noise from the readout dark is currently not taken into account. We develop a method to estimate the readout dark noise properties in ACS/WFC observations. We update the error (ERR) extensions of superbias images to include the appropriate noise from the ambient readout dark gradient and stable hot columns. In recent data, this amounts to about 5 e-/pixel added variance in the rows farthest from the WFC serial registers, and about 7 to 30 e-/pixel added variance along the stable hot columns. We also flag unstable hot columns in the superbias data quality (DQ) extensions. The new reference file pipeline for ACS/WFC implements these updates to our superbias creation process.

High-Order Methods for Computational Physics

DTIC Science & Technology

1999-03-01

computation is running in 278 Ronald D. Henderson parallel. Instead we use the concept of a voxel database (VDB) of geometric positions in the mesh [85...processor 0 Fig. 4.19. Connectivity and communications axe established by building a voxel database (VDB) of positions. A VDB maps each position to a...studies such as the highly accurate stability computations considered help expand the database for this benchmark problem. The two-dimensional linear

Implicit mesh discontinuous Galerkin methods and interfacial gauge methods for high-order accurate interface dynamics, with applications to surface tension dynamics, rigid body fluid-structure interaction, and free surface flow: Part I

NASA Astrophysics Data System (ADS)

Saye, Robert

2017-09-01

In this two-part paper, a high-order accurate implicit mesh discontinuous Galerkin (dG) framework is developed for fluid interface dynamics, facilitating precise computation of interfacial fluid flow in evolving geometries. The framework uses implicitly defined meshes-wherein a reference quadtree or octree grid is combined with an implicit representation of evolving interfaces and moving domain boundaries-and allows physically prescribed interfacial jump conditions to be imposed or captured with high-order accuracy. Part one discusses the design of the framework, including: (i) high-order quadrature for implicitly defined elements and faces; (ii) high-order accurate discretisation of scalar and vector-valued elliptic partial differential equations with interfacial jumps in ellipticity coefficient, leading to optimal-order accuracy in the maximum norm and discrete linear systems that are symmetric positive (semi)definite; (iii) the design of incompressible fluid flow projection operators, which except for the influence of small penalty parameters, are discretely idempotent; and (iv) the design of geometric multigrid methods for elliptic interface problems on implicitly defined meshes and their use as preconditioners for the conjugate gradient method. Also discussed is a variety of aspects relating to moving interfaces, including: (v) dG discretisations of the level set method on implicitly defined meshes; (vi) transferring state between evolving implicit meshes; (vii) preserving mesh topology to accurately compute temporal derivatives; (viii) high-order accurate reinitialisation of level set functions; and (ix) the integration of adaptive mesh refinement. In part two, several applications of the implicit mesh dG framework in two and three dimensions are presented, including examples of single phase flow in nontrivial geometry, surface tension-driven two phase flow with phase-dependent fluid density and viscosity, rigid body fluid-structure interaction, and free surface flow. A class of techniques known as interfacial gauge methods is adopted to solve the corresponding incompressible Navier-Stokes equations, which, compared to archetypical projection methods, have a weaker coupling between fluid velocity, pressure, and interface position, and allow high-order accurate numerical methods to be developed more easily. Convergence analyses conducted throughout the work demonstrate high-order accuracy in the maximum norm for all of the applications considered; for example, fourth-order spatial accuracy in fluid velocity, pressure, and interface location is demonstrated for surface tension-driven two phase flow in 2D and 3D. Specific application examples include: vortex shedding in nontrivial geometry, capillary wave dynamics revealing fine-scale flow features, falling rigid bodies tumbling in unsteady flow, and free surface flow over a submersed obstacle, as well as high Reynolds number soap bubble oscillation dynamics and vortex shedding induced by a type of Plateau-Rayleigh instability in water ripple free surface flow. These last two examples compare numerical results with experimental data and serve as an additional means of validation; they also reveal physical phenomena not visible in the experiments, highlight how small-scale interfacial features develop and affect macroscopic dynamics, and demonstrate the wide range of spatial scales often at play in interfacial fluid flow.

Implicit mesh discontinuous Galerkin methods and interfacial gauge methods for high-order accurate interface dynamics, with applications to surface tension dynamics, rigid body fluid-structure interaction, and free surface flow: Part II

NASA Astrophysics Data System (ADS)

Saye, Robert

2017-09-01

In this two-part paper, a high-order accurate implicit mesh discontinuous Galerkin (dG) framework is developed for fluid interface dynamics, facilitating precise computation of interfacial fluid flow in evolving geometries. The framework uses implicitly defined meshes-wherein a reference quadtree or octree grid is combined with an implicit representation of evolving interfaces and moving domain boundaries-and allows physically prescribed interfacial jump conditions to be imposed or captured with high-order accuracy. Part one discusses the design of the framework, including: (i) high-order quadrature for implicitly defined elements and faces; (ii) high-order accurate discretisation of scalar and vector-valued elliptic partial differential equations with interfacial jumps in ellipticity coefficient, leading to optimal-order accuracy in the maximum norm and discrete linear systems that are symmetric positive (semi)definite; (iii) the design of incompressible fluid flow projection operators, which except for the influence of small penalty parameters, are discretely idempotent; and (iv) the design of geometric multigrid methods for elliptic interface problems on implicitly defined meshes and their use as preconditioners for the conjugate gradient method. Also discussed is a variety of aspects relating to moving interfaces, including: (v) dG discretisations of the level set method on implicitly defined meshes; (vi) transferring state between evolving implicit meshes; (vii) preserving mesh topology to accurately compute temporal derivatives; (viii) high-order accurate reinitialisation of level set functions; and (ix) the integration of adaptive mesh refinement. In part two, several applications of the implicit mesh dG framework in two and three dimensions are presented, including examples of single phase flow in nontrivial geometry, surface tension-driven two phase flow with phase-dependent fluid density and viscosity, rigid body fluid-structure interaction, and free surface flow. A class of techniques known as interfacial gauge methods is adopted to solve the corresponding incompressible Navier-Stokes equations, which, compared to archetypical projection methods, have a weaker coupling between fluid velocity, pressure, and interface position, and allow high-order accurate numerical methods to be developed more easily. Convergence analyses conducted throughout the work demonstrate high-order accuracy in the maximum norm for all of the applications considered; for example, fourth-order spatial accuracy in fluid velocity, pressure, and interface location is demonstrated for surface tension-driven two phase flow in 2D and 3D. Specific application examples include: vortex shedding in nontrivial geometry, capillary wave dynamics revealing fine-scale flow features, falling rigid bodies tumbling in unsteady flow, and free surface flow over a submersed obstacle, as well as high Reynolds number soap bubble oscillation dynamics and vortex shedding induced by a type of Plateau-Rayleigh instability in water ripple free surface flow. These last two examples compare numerical results with experimental data and serve as an additional means of validation; they also reveal physical phenomena not visible in the experiments, highlight how small-scale interfacial features develop and affect macroscopic dynamics, and demonstrate the wide range of spatial scales often at play in interfacial fluid flow.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolotnikov, A. E., E-mail: bolotnik@bnl.gov; Ackley, K.; Camarda, G. S.

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm{sup 3} detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We presentmore » the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays’ performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.« less

Three-dimensional cross point readout detector design for including depth information

NASA Astrophysics Data System (ADS)

Lee, Seung-Jae; Baek, Cheol-Ha

2018-04-01

We designed a depth-encoding positron emission tomography (PET) detector using a cross point readout method with wavelength-shifting (WLS) fibers. To evaluate the characteristics of the novel detector module and the PET system, we used the DETECT2000 to perform optical photon transport in the crystal array. The GATE was also used. The detector module is made up of four layers of scintillator arrays, the five layers of WLS fiber arrays, and two sensor arrays. The WLS fiber arrays in each layer cross each other to transport light to each sensor array. The two sensor arrays are coupled to the forward and left sides of the WLS fiber array, respectively. The identification of three-dimensional pixels was determined using a digital positioning algorithm. All pixels were well decoded, with the system resolution ranging from 2.11 mm to 2.29 mm at full width at half maximum (FWHM).

Two-dimensional ultrahigh-density X-ray optical memory.

PubMed

Bezirganyan, Hakob P; Bezirganyan, Siranush E; Bezirganyan, Hayk H; Bezirganyan, Petros H

2007-01-01

Most important aspect of nanotechnology applications in the information ultrahigh storage is the miniaturization of data carrier elements of the storage media with emphasis on the long-term stability. Proposed two-dimensional ultrahigh-density X-ray optical memory, named X-ROM, with long-term stability is an information carrier basically destined for digital data archiving. X-ROM is a semiconductor wafer, in which the high-reflectivity nanosized X-ray mirrors are embedded. Data are encoded due to certain positions of the mirrors. Ultrahigh-density data recording procedure can e.g., be performed via mask-less zone-plate-array lithography (ZPAL), spatial-phase-locked electron-beam lithography (SPLEBL), or focused ion-beam lithography (FIB). X-ROM manufactured by nanolithography technique is a write-once memory useful for terabit-scale memory applications, if the surface area of the smallest recording pits is less than 100 nm2. In this case the X-ROM surface-storage capacity of a square centimetre becomes by two orders of magnitude higher than the volumetric data density really achieved for three-dimensional optical data storage medium. Digital data read-out procedure from proposed X-ROM can e.g., be performed via glancing-angle incident X-ray micro beam (GIX) using the well-developed X-ray reflectometry technique. In presented theoretical paper the crystal-analyser operating like an image magnifier is added to the set-up of X-ROM data handling system for the purpose analogous to case of application the higher numerical aperture objective in optical data read-out system. We also propose the set-up of the X-ROM readout system based on more the one incident X-ray micro beam. Presented scheme of two-beam data handling system, which operates on two mutually perpendicular well-collimated monochromatic incident X-ray micro beams, essentially increases the reliability of the digital information read-out procedure. According the graphs of characteristic functions presented in paper, one may choose optimally the incident radiation wavelength, as well as the angle of incidence of X-ray micro beams, appropriate for proposed digital data read-out procedure.

Gear Mesh Loss-of-Lubrication Experiments and Analytical Simulation

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Polly, Joseph; Morales, Wilfredo

2011-01-01

An experimental program to determine the loss-of-lubrication (LOL) characteristics of spur gears in an aerospace simulation test facility has been completed. Tests were conducted using two different emergency lubricant types: (1) an oil mist system (two different misted lubricants) and (2) a grease injection system (two different grease types). Tests were conducted using a NASA Glenn test facility normally used for conducting contact fatigue. Tests were run at rotational speeds up to 10000 rpm using two different gear designs and two different gear materials. For the tests conducted using an air-oil misting system, a minimum lubricant injection rate was determined to permit the gear mesh to operate without failure for at least 1 hr. The tests allowed an elevated steady state temperature to be established. A basic 2-D heat transfer simulation has been developed to investigate temperatures of a simulated gear as a function of frictional behavior. The friction (heat generation source) between the meshing surfaces is related to the position in the meshing cycle, the load applied, and the amount of lubricant in the contact. Experimental conditions will be compared to those from the 2-D simulation.

Capillary Liquid Acquisition Device Heat Entrapment

NASA Technical Reports Server (NTRS)

Bolshinskiy, L. G.; Hastings, L. J.; Statham, G.; Turpin, J. B.

2007-01-01

Cryogenic liquid acquisition devices (LADs) for space-based propulsion interface directly with the feed system, which can be a significant heat leak source. Further, the accumulation of thermal energy within LAD channels can lead to the loss of subcooled propellant conditions and result in feed system cavitation during propellant outflow. Therefore, the fundamental question addressed by this program was: To what degree is natural convection in a cryogenic liquid constrained by the capillary screen meshes envisioned for LADs? Testing was first conducted with water as the test fluid, followed by LN2 tests. In either case, the basic experimental approach was to heat the bottom of a cylindrical column of test fluid to establish stratification patterns measured by temperature sensors located above and below a horizontal screen barrier position. Experimentation was performed without barriers, with screens, and with a solid barrier. The two screen meshes tested were those typically used by LAD designers, 200x1400 and 325x2300, both with Twill Dutch Weave. Upon consideration of both the water and LN2 data, it was concluded that heat transfer across the screen meshes was dependent upon barrier thermal conductivity and that the capillary screen meshes were impervious to natural convection currents.

Cryogenic Capillary Screen Heat Entrapment

NASA Technical Reports Server (NTRS)

Bolshinskiy, L.G.; Hastings, L.J.; Stathman, G.

2007-01-01

Cryogenic liquid acquisition devices (LADs) for space-based propulsion interface directly with the feed system, which can be a significant heat leak source. Further, the accumulation of thermal energy within LAD channels can lead to the loss of sub-cooled propellant conditions and result in feed system cavitation during propellant outflow. Therefore, the fundamental question addressed by this program was: "To what degree is natural convection in a cryogenic liquid constrained by the capillary screen meshes envisioned for LADs.?"Testing was first conducted with water as the test fluid, followed by LN2 tests. In either case, the basic experimental approach was to heat the bottom of a cylindrical column of test fluid to establish stratification patterns measured by temperature sensors located above and below a horizontal screen barrier position. Experimentation was performed without barriers, with screens, and with a solid barrier. The two screen meshes tested were those typically used by LAD designers, "200x1400" and "325x2300", both with Twill Dutch Weave. Upon consideration of both the water and LN2 data it was concluded that heat transfer across the screen meshes was dependent upon barrier thermal conductivity and that the capillary screen meshes were impervious to natural convection currents.

MuTRiG: a mixed signal Silicon Photomultiplier readout ASIC with high timing resolution and gigabit data link

NASA Astrophysics Data System (ADS)

Chen, H.; Briggl, K.; Eckert, P.; Harion, T.; Munwes, Y.; Shen, W.; Stankova, V.; Schultz-Coulon, H. C.

2017-01-01

MuTRiG is a mixed signal Silicon Photomultiplier readout ASIC designed in UMC 180 nm CMOS technology for precise timing and high event rate applications in high energy physics experiments and medical imaging. It is dedicated to the readout of the scintillating fiber detector and the scintillating tile detector of the Mu3e experiment. The MuTRiG chip extends the excellent timing performance of the STiCv3 chip with a fast digital readout for high rate applications. The high timing performance of the fully differential SiPM readout channels and 50 ps time binning TDCs are complemented by an upgraded digital readout logic and a 1.28 Gbps LVDS serial data link. The design of the chip and the characterization results of the analog front-end, TDC and the LVDS data link are presented.

DIODE STEERED MANGETIC-CORE MEMORY

DOEpatents

Melmed, A.S.; Shevlin, R.T.; Laupheimer, R.

1962-09-18

A word-arranged magnetic-core memory is designed for use in a digital computer utilizing the reverse or back current property of the semi-conductor diodes to restore the information in the memory after read-out. In order to ob tain a read-out signal from a magnetic core storage unit, it is necessary to change the states of some of the magnetic cores. In order to retain the information in the memory after read-out it is then necessary to provide a means to return the switched cores to their states before read-out. A rewrite driver passes a pulse back through each row of cores in which some switching has taken place. This pulse combines with the reverse current pulses of diodes for each column in which a core is switched during read-out to cause the particular cores to be switched back into their states prior to read-out. (AEC)

Hydrodynamic Modeling of Air Blast Propagation from the Humble Redwood Chemical High Explosive Detonations Using GEODYN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chipman, V D

Two-dimensional axisymmetric hydrodynamic models were developed using GEODYN to simulate the propagation of air blasts resulting from a series of high explosive detonations conducted at Kirtland Air Force Base in August and September of 2007. Dubbed Humble Redwood I (HR-1), these near-surface chemical high explosive detonations consisted of seven shots of varying height or depth of burst. Each shot was simulated numerically using GEODYN. An adaptive mesh refinement scheme based on air pressure gradients was employed such that the mesh refinement tracked the advancing shock front where sharp discontinuities existed in the state variables, but allowed the mesh to sufficientlymore » relax behind the shock front for runtime efficiency. Comparisons of overpressure, sound speed, and positive phase impulse from the GEODYN simulations were made to the recorded data taken from each HR-1 shot. Where the detonations occurred above ground or were shallowly buried (no deeper than 1 m), the GEODYN model was able to simulate the sound speeds, peak overpressures, and positive phase impulses to within approximately 1%, 23%, and 6%, respectively, of the actual recorded data, supporting the use of numerical simulation of the air blast as a forensic tool in determining the yield of an otherwise unknown explosion.« less

Irregular-regular mode oscillations inside plasma bubble and its fractal analysis in glow discharge magnetized plasma

NASA Astrophysics Data System (ADS)

Megalingam, Mariammal; Hari Prakash, N.; Solomon, Infant; Sarma, Arun; Sarma, Bornali

2017-04-01

Experimental evidence of different kinds of oscillations in floating potential fluctuations of glow discharge magnetized plasma is being reported. A spherical gridded cage is inserted into the ambient plasma volume for creating plasma bubbles. Plasma is produced between a spherical mesh grid and chamber. The spherical mesh grid of 80% optical transparency is connected to the positive terminal of power supply and considered as anode. Two Langmuir probes are kept in the ambient plasma to measure the floating potential fluctuations in different positions within the system, viz., inside and outside the spherical mesh grid. At certain conditions of discharge voltage (Vd) and magnetic field, irregular to regular mode appears, and it shows chronological changes with respect to magnetic field. Further various nonlinear analyses such as Recurrence Plot, Hurst exponent, and Lyapunov exponent have been carried out to investigate the dynamics of oscillation at a range of discharge voltages and external magnetic fields. Determinism, entropy, and Lmax are important measures of Recurrence Quantification Analysis which indicate an irregular to regular transition in the dynamics of the fluctuations. Furthermore, behavior of the plasma oscillation is characterized by the technique called multifractal detrended fluctuation analysis to explore the nature of the fluctuations. It reveals that it has a multifractal nature and behaves as a long range correlated process.

Optimization of multiple turbine arrays in a channel with tidally reversing flow by numerical modelling with adaptive mesh.

PubMed

Divett, T; Vennell, R; Stevens, C

2013-02-28

At tidal energy sites, large arrays of hundreds of turbines will be required to generate economically significant amounts of energy. Owing to wake effects within the array, the placement of turbines within will be vital to capturing the maximum energy from the resource. This study presents preliminary results using Gerris, an adaptive mesh flow solver, to investigate the flow through four different arrays of 15 turbines each. The goal is to optimize the position of turbines within an array in an idealized channel. The turbines are represented as areas of increased bottom friction in an adaptive mesh model so that the flow and power capture in tidally reversing flow through large arrays can be studied. The effect of oscillating tides is studied, with interesting dynamics generated as the tidal current reverses direction, forcing turbulent flow through the array. The energy removed from the flow by each of the four arrays is compared over a tidal cycle. A staggered array is found to extract 54 per cent more energy than a non-staggered array. Furthermore, an array positioned to one side of the channel is found to remove a similar amount of energy compared with an array in the centre of the channel.

Development of a Massive, Highly Multiplexible, Phonon-Mediated Particle Detector Using Kinetic Inductance Detectors

NASA Astrophysics Data System (ADS)

Chang, Y.-Y.; Cornell, B.; Aralis, T.; Bumble, B.; Golwala, S. R.

2018-04-01

We present a status update on the development of a phonon-mediated particle detector using kinetic inductance detector (KID). The design is intended for O(1) kg substrate, using O(102) KIDs on a single readout line, to image the athermal phonon distribution at < 1 mm position resolution and O(10) eV energy resolution. The design specification is set by the need to improve position reconstruction fidelity while maintaining low energy threshold for future rare-event searches such as for low-mass dark matter. We report on the design, which shows negligible crosstalk and > 95% inductor current uniformity, using the coplanar waveguide feedline, ground shield, and a new class of KIDs with symmetric coplanar stripline (sCPS) inductor. The multiplexing is designed upon the frequency-geometry relation we develop for the sCPS KIDs. We introduce the fabrications of the Nb RF assessment prototypes and the high phonon collection efficiency Al-Nb devices. We achieve ≲ 0.07% frequency displacement on a 80-KID RF assessment prototype, and the result indicates that we may place more than 180 resonances in our 0.4 GHz readout band with minimal frequency misordering. The coupling quality factors are ˜ 105 as designed. Finally, we update our work in progress in fabricating the O(102) KID, bi-material, O(1) kg detectors, and the expected position and energy resolutions.

Minimal Invasive Linea Alba Reconstruction for the Treatment of Umbilical and Epigastric Hernias with Coexisting Rectus Abdominis Diastasis.

PubMed

Köhler, Gernot; Fischer, Ines; Kaltenböck, Richard; Schrittwieser, Rudolf

2018-04-05

Patients with umbilical or epigastric hernias benefit from mesh- based repairs, and even more so if a concomitant rectus diastasis (RD) is present. The ideal technique is, however, still under debate. In this study we introduce the minimal invasive linea alba reconstruction (MILAR) with the supraaponeurotic placement of a fully absorbable synthetic mesh. Midline reconstruction with anterior rectus sheath repair and mesh augmentation by an open approach is a well-known surgical technique for ventral hernia repair. Between December 1, 2016, and November 30, 2017, 20 patients with symptomatic umbilical and/or epigastric hernias, and coexisting RD underwent a minimally invasive complete reconstruction of the midline through a small access route. The inner part of both incised and medialized anterior rectus sheaths was replaced by a fully absorbable synthetic mesh placed in a supraaponeurotic position. Patients were hospitalized for an average of 4 days and the mean operating time was 79 minutes. The mean hernia defect size was 1.5 cm in diameter and the mean mesh size was recorded as 15.8 cm in length and 5.2 cm in width. Two patients sustained surgical postoperative complications in terms of symptomatic seroma occurrences with successful interventional treatment.The early results (mean follow-up period of 5 months) showed no recurrences and only 1 patient reported occasional pain following exertion without rest. MILAR is a modification of the recently published endoscopic linea alba reconstruction restoring the normal anatomy of the abdominal wall. A new linea alba is formed with augmentation of autologous tissue consisting of the plicated anterior rectus sheaths. Supraaponeurotic placement of a fully absorbable synthetic mesh eliminates potential long-term mesh-associated complications. Regarding MILAR, there is no need for endoscopic equipment due to the uniquely designed flexible lighted retractors, meaning one assistant less is required.

Laparoscopic repair of inguinal hernias using an intraperitoneal onlay mesh technique and a Parietex composite mesh fixed with fibrin glue (Tissucol). Personal technique and preliminary results.

PubMed

Olmi, Stefano; Scaini, Alberto; Erba, Luigi; Bertolini, Aimone; Croce, Enrico

2007-11-01

Laparoscopic repair of inguinal hernias is usually achieved by totally extraperitoneal (TEP) or transabdominal preperitoneal (TAPP) techniques. The intraperitoneal onlay mesh (IPOM) could be an interesting alternative as it is much easier to perform and faster to execute. This technique is subject to correct selection of indications and to demonstration of its safety. From January 2003 to January 2006 we performed 61 laparoscopic hernia procedures on 60 selected patients (60 males with a mean age of 60 and mean weight of 76 kg) with an IPOM technique combining the Parietex composite mesh (12 cm circular model) and a fibrin glue (Tissucol) for its fixation. The glue was diluted to increase fixation time and applied to the mesh prior to positioning on the hernia defect. Mean operative time was 10 minutes. Mean hernia diameter was 2.5 cm (+/- 0.8 cm). 10 hernias were direct, 51 were indirect and 10 out of 61 were recurrent. We did not convert any of the laparoscopic procedures. Mean hospital stay was one day; mean recovery time for working and general physical activities was five days. Patients were checked after one week, 1-3-6 months and 1-2 years. Average follow up time was 23.7 months. 1.6 % of patients showed short-term complications: one trocar site haematoma. No additional complications were reported; particularly, we had no recurrence, no seroma, no mesh migration, and no bowel obstruction or fistula. Results of this study show intraperitoneal (IP) tolerance to this kind of mesh and the safety of its fixation with Tissucol. The absence of recurrence and complications could be a good reason to extend the indication of IPOM hernia repair. However, these preliminary results should be confirmed by longer follow-up.

Theme trends and knowledge structure on choroidal neovascularization: a quantitative and co-word analysis.

PubMed

Zhao, Fangkun; Shi, Bei; Liu, Ruixin; Zhou, Wenkai; Shi, Dong; Zhang, Jinsong

2018-04-03

The distribution pattern and knowledge structure of choroidal neovascularization (CNV) was surveyed based on literatures in PubMed. Published scientific papers about CNV were retrieved from Jan 1st, 2012 to May 31st, 2017. Extracted MeSH terms were analyzed quantitatively by using Bibliographic Item Co-Occurrence Matrix Builder (BICOMB) and high-frequency MeSH terms were identified. Hierarchical cluster analysis was conducted by SPSS 19.0 according to the MeSH term-source article matrix. High-frequency MeSH terms co-occurrence matrix was constructed to support strategic diagram and social network analysis (SNA). According to the searching strategy, all together 2366 papers were included, and the number of annual papers changed slightly from Jan 1st, 2012 to May 31st, 2017. Among all the extracted MeSH terms, 44 high-frequency MeSH terms were identified and hotspots were clustered into 6 categories. In the strategic diagram, clinical drug therapy, pathology and diagnosis related researches of CNV were well developed. In contrast, the metabolism, etiology, complications, prevention and control of CNV in animal models, and genetics related researches of CNV were relatively immature, which offers potential research space for future study. As for the SNA result, the position status of each component was described by the centrality values. The studies on CNV are relatively divergent and the 6 research categories concluded from this study could reflect the publication trends on CNV to some extent. By providing a quantitative bibliometric research across a 5-year span, it could help to depict an overall command of the latest topics and provide some hints for researchers when launching new projects.

Repositioning the knee joint in human body FE models using a graphics-based technique.

PubMed

Jani, Dhaval; Chawla, Anoop; Mukherjee, Sudipto; Goyal, Rahul; Vusirikala, Nataraju; Jayaraman, Suresh

2012-01-01

Human body finite element models (FE-HBMs) are available in standard occupant or pedestrian postures. There is a need to have FE-HBMs in the same posture as a crash victim or to be configured in varying postures. Developing FE models for all possible positions is not practically viable. The current work aims at obtaining a posture-specific human lower extremity model by reconfiguring an existing one. A graphics-based technique was developed to reposition the lower extremity of an FE-HBM by specifying the flexion-extension angle. Elements of the model were segregated into rigid (bones) and deformable components (soft tissues). The bones were rotated about the flexion-extension axis followed by rotation about the longitudinal axis to capture the twisting of the tibia. The desired knee joint movement was thus achieved. Geometric heuristics were then used to reposition the skin. A mapping defined over the space between bones and the skin was used to regenerate the soft tissues. Mesh smoothing was then done to augment mesh quality. The developed method permits control over the kinematics of the joint and maintains the initial mesh quality of the model. For some critical areas (in the joint vicinity) where element distortion is large, mesh smoothing is done to improve mesh quality. A method to reposition the knee joint of a human body FE model was developed. Repositions of a model from 9 degrees of flexion to 90 degrees of flexion in just a few seconds without subjective interventions was demonstrated. Because the mesh quality of the repositioned model was maintained to a predefined level (typically to the level of a well-made model in the initial configuration), the model was suitable for subsequent simulations.

High-Fidelity Single-Shot Readout for a Spin Qubit via an Enhanced Latching Mechanism

NASA Astrophysics Data System (ADS)

Harvey-Collard, Patrick; D'Anjou, Benjamin; Rudolph, Martin; Jacobson, N. Tobias; Dominguez, Jason; Ten Eyck, Gregory A.; Wendt, Joel R.; Pluym, Tammy; Lilly, Michael P.; Coish, William A.; Pioro-Ladrière, Michel; Carroll, Malcolm S.

2018-04-01

The readout of semiconductor spin qubits based on spin blockade is fast but suffers from a small charge signal. Previous work suggested large benefits from additional charge mapping processes; however, uncertainties remain about the underlying mechanisms and achievable fidelity. In this work, we study the single-shot fidelity and limiting mechanisms for two variations of an enhanced latching readout. We achieve average single-shot readout fidelities greater than 99.3% and 99.86% for the conventional and enhanced readout, respectively, the latter being the highest to date for spin blockade. The signal amplitude is enhanced to a full one-electron signal while preserving the readout speed. Furthermore, layout constraints are relaxed because the charge sensor signal is no longer dependent on being aligned with the conventional (2,0)-(1,1) charge dipole. Silicon donor-quantum-dot qubits are used for this study, for which the dipole insensitivity substantially relaxes donor placement requirements. One of the readout variations also benefits from a parametric lifetime enhancement by replacing the spin-relaxation process with a charge-metastable one. This provides opportunities to further increase the fidelity. The relaxation mechanisms in the different regimes are investigated. This work demonstrates a readout that is fast, has a one-electron signal, and results in higher fidelity. It further predicts that going beyond 99.9% fidelity in a few microseconds of measurement time is within reach.

The transmission of stress to grafted bone inside a titanium mesh cage used in anterior column reconstruction after total spondylectomy: a finite-element analysis.

PubMed

Akamaru, Tomoyuki; Kawahara, Norio; Sakamoto, Jiro; Yoshida, Akira; Murakami, Hideki; Hato, Taizo; Awamori, Serina; Oda, Juhachi; Tomita, Katsuro

2005-12-15

A finite-element study of posterior alone or anterior/posterior combined instrumentation following total spondylectomy and replacement with a titanium mesh cage used as an anterior strut. To compare the effect of posterior instrumentation versus anterior/posterior instrumentation on transmission of the stress to grafted bone inside a titanium mesh cage following total spondylectomy. The most recent reconstruction techniques following total spondylectomy for malignant spinal tumor include a titanium mesh cage filled with autologous bone as an anterior strut. The need for additional anterior instrumentation with posterior pedicle screws and rods is controversial. Transmission of the mechanical stress to grafted bone inside a titanium mesh cage is important for fusion and remodeling. To our knowledge, there are no published reports comparing the load-sharing properties of the different reconstruction methods following total spondylectomy. A 3-dimensional finite-element model of the reconstructed spine (T10-L4) following total spondylectomy at T12 was constructed. A Harms titanium mesh cage (DePuy Spine, Raynham, MA) was positioned as an anterior replacement, and 3 types of the reconstruction methods were compared: (1) multilevel posterior instrumentation (MPI) (i.e., posterior pedicle screws and rods at T10-L2 without anterior instrumentation); (2) MPI with anterior instrumentation (MPAI) (i.e., MPAI [Kaneda SR; DePuy Spine] at T11-L1); and (3) short posterior and anterior instrumentation (SPAI) (i.e., posterior pedicle screws and rods with anterior instrumentation at T11-L1). The mechanical energy stress distribution exerted inside the titanium mesh cage was evaluated and compared by finite-element analysis for the 3 different reconstruction methods. Simulated forces were applied to give axial compression, flexion, extension, and lateral bending. In flexion mode, the energy stress distribution in MPI was higher than 3.0 x 10 MPa in 73.0% of the total volume inside the titanium mesh cage, while 38.0% in MPAI, and 43.3% in SPAI. In axial compression and extension modes, there were no remarkable differences for each reconstruction method. In left-bending mode, there was little stress energy in the cancellous bone inside the titanium mesh cage in MPAI and SPAI. This experiment shows that from the viewpoint of stress shielding, the reconstruction method, using additional anterior instrumentation with posterior pedicle screws (MPAI and SPAI), stress shields the cancellous bone inside the titanium mesh cage to a higher degree than does the system using posterior pedicle screw fixation alone (MPI). Thus, a reconstruction method with no anterior fixation should be better at allowing stress for remodeling of the bone graft inside the titanium mesh cage.

MRI Guided Brain Stimulation without the Use of a Neuronavigation System

PubMed Central

Vaghefi, Ehsan; Byblow, Winston D.; Stinear, Cathy M.; Thompson, Benjamin

2015-01-01

A key issue in the field of noninvasive brain stimulation (NIBS) is the accurate localization of scalp positions that correspond to targeted cortical areas. The current gold standard is to combine structural and functional brain imaging with a commercially available “neuronavigation” system. However, neuronavigation systems are not commonplace outside of specialized research environments. Here we describe a technique that allows for the use of participant-specific functional and structural MRI data to guide NIBS without a neuronavigation system. Surface mesh representations of the head were generated using Brain Voyager and vectors linking key anatomical landmarks were drawn on the mesh. Our technique was then used to calculate the precise distances on the scalp corresponding to these vectors. These calculations were verified using actual measurements of the head and the technique was used to identify a scalp position corresponding to a brain area localized using functional MRI. PMID:26413537

General-purpose readout electronics for white neutron source at China Spallation Neutron Source

NASA Astrophysics Data System (ADS)

Wang, Q.; Cao, P.; Qi, X.; Yu, T.; Ji, X.; Xie, L.; An, Q.

2018-01-01

The under-construction White Neutron Source (WNS) at China Spallation Neutron Source is a facility for accurate measurements of neutron-induced cross section. Seven spectrometers are planned at WNS. As the physical objectives of each spectrometer are different, the requirements for readout electronics are not the same. In order to simplify the development of the readout electronics, this paper presents a general method for detector signal readout. This method has advantages of expansibility and flexibility, which makes it adaptable to most detectors at WNS. In the WNS general-purpose readout electronics, signals from any kinds of detectors are conditioned by a dedicated signal conditioning module corresponding to this detector, and then digitized by a common waveform digitizer with high speed and high precision (1 GSPS at 12-bit) to obtain the full waveform data. The waveform digitizer uses a field programmable gate array chip to process the data stream and trigger information in real time. PXI Express platform is used to support the functionalities of data readout, clock distribution, and trigger information exchange between digitizers and trigger modules. Test results show that the performance of the WNS general-purpose readout electronics can meet the requirements of the WNS spectrometers.

Medical gamma ray imaging

DOEpatents

Osborne, Louis S.; Lanza, Richard C.

1984-01-01

A method and apparatus for determining the distribution of a position-emitting radioisotope into an object, the apparatus consisting of a wire mesh radiation converter, an ionizable gas for propagating ionization events caused by electrodes released by the converter, a drift field, a spatial position detector and signal processing circuitry for correlating near-simultaneous ionization events and determining their time differences, whereby the position sources of back-to-back collinear radiation can be located and a distribution image constructed.

Control of nanoparticle size and amount by using the mesh grid and applying DC-bias to the substrate in silane ICP-CVD process

NASA Astrophysics Data System (ADS)

Yoo, Seung-Wan; Hwang, Nong-Moon; You, Shin-Jae; Kim, Jung-Hyung; Seong, Dae-Jin

2017-11-01

The effect of applying a bias to the substrate on the size and amount of charged crystalline silicon nanoparticles deposited on the substrate was investigated in the inductively coupled plasma chemical vapor deposition process. By inserting the grounded grid with meshes above the substrate, the region just above the substrate was separated from the plasma. Thereby, crystalline Si nanoparticles formed by the gas-phase reaction in the plasma could be deposited directly on the substrate, successfully avoiding the formation of a film. Moreover, the size and the amount of deposited nanoparticles could be changed by applying direct current bias to the substrate. When the grid of 1 × 1-mm-sized mesh was used, the nanoparticle flux was increased as the negative substrate bias increased from 0 to - 50 V. On the other hand, when a positive bias was applied to the substrate, Si nanoparticles were not deposited at all. Regardless of substrate bias voltages, the most frequently observed nanoparticles synthesized with the grid of 1 × 1-mm-sized mesh had the size range of 10-12 nm in common. When the square mesh grid of 2-mm size was used, as the substrate bias was increased from - 50 to 50 V, the size of the nanoparticles observed most frequently increased from the range of 8-10 to 40-45 nm but the amount that was deposited on the substrate decreased.

LDEF Experiment P0006 Linear Energy Transfer Spectrum Measurement (LETSME) quick look report

NASA Technical Reports Server (NTRS)

1990-01-01

A preliminary analysis of the various passive radiation detector materials included in the P0006 LETSME experiment flown on LDEF (Long Duration Exposure Facility) is presented. It consists of four tasks: (1) readout and analysis of thermoluminescent detectors (TLD); (2) readout and analysis of fission foil/mica detectors; (3) readout and analysis of (6)LiF/CR-39 detectors; and (4) preliminary processing and readout of CR-39 and polycarbonate plastic nuclear track detectors (PNTD).

Cherenkov radiation-based three-dimensional position-sensitive PET detector: A Monte Carlo study.

PubMed

Ota, Ryosuke; Yamada, Ryoko; Moriya, Takahiro; Hasegawa, Tomoyuki

2018-05-01

Cherenkov radiation has recently received attention due to its prompt emission phenomenon, which has the potential to improve the timing performance of radiation detectors dedicated to positron emission tomography (PET). In this study, a Cherenkov-based three-dimensional (3D) position-sensitive radiation detector was proposed, which is composed of a monolithic lead fluoride (PbF 2 ) crystal and a photodetector array of which the signals can be readout independently. Monte Carlo simulations were performed to estimate the performance of the proposed detector. The position- and time resolution were evaluated under various practical conditions. The radiator size and various properties of the photodetector, e.g., readout pitch and single photon timing resolution (SPTR), were parameterized. The single photon time response of the photodetector was assumed to be a single Gaussian for the simplification. The photo detection efficiency of the photodetector was ideally 100% for all wavelengths. Compton scattering was included in simulations, but partly analyzed. To estimate the position at which a γ-ray interacted in the Cherenkov radiator, the center-of-gravity (COG) method was employed. In addition, to estimate the depth-of-interaction (DOI) principal component analysis (PCA), which is a multivariate analysis method and has been used to identify the patterns in data, was employed. The time-space distribution of Cherenkov photons was quantified to perform PCA. To evaluate coincidence time resolution (CTR), the time difference of two independent γ-ray events was calculated. The detection time was defined as the first photon time after the SPTR of the photodetector was taken into account. The position resolution on the photodetector plane could be estimated with high accuracy, by using a small number of Cherenkov photons. Moreover, PCA showed an ability to estimate the DOI. The position resolution heavily depends on the pitch of the photodetector array and the radiator thickness. If the readout pitch were ideally 0 and practically 3 mm, a full-width at half-maximum (FWHM) of 0.348 and 1.92 mm was achievable with a 10-mm-thick PbF 2 crystal, respectively. Furthermore, first-order correlation could be observed between the primary principal component and the true DOI. To obtain a coincidence timing resolution better than 100-ps FWHM with a 20-mm-thick PbF 2 crystal, a photodetector with SPTR of better than σ = 30 ps was necessary. From these results, the improvement of SPTR allows us to achieve CTR better than 100-ps FWHM, even in the case where a 20-mm-thick radiator is used. Our proposed detector has the potential to estimate the 3D interaction position of γ-rays in the radiator, using only time and space information of Cherenkov photons. © 2018 American Association of Physicists in Medicine.

Digital radiography using amorphous selenium: photoconductively activated switch (PAS) readout system.

PubMed

Reznik, Nikita; Komljenovic, Philip T; Germann, Stephen; Rowlands, John A

2008-03-01

A new amorphous selenium (a-Se) digital radiography detector is introduced. The proposed detector generates a charge image in the a-Se layer in a conventional manner, which is stored on electrode pixels at the surface of the a-Se layer. A novel method, called photoconductively activated switch (PAS), is used to read out the latent x-ray charge image. The PAS readout method uses lateral photoconduction at the a-Se surface which is a revolutionary modification of the bulk photoinduced discharge (PID) methods. The PAS method addresses and eliminates the fundamental weaknesses of the PID methods--long readout times and high readout noise--while maintaining the structural simplicity and high resolution for which PID optical readout systems are noted. The photoconduction properties of the a-Se surface were investigated and the geometrical design for the electrode pixels for a PAS radiography system was determined. This design was implemented in a single pixel PAS evaluation system. The results show that the PAS x-ray induced output charge signal was reproducible and depended linearly on the x-ray exposure in the diagnostic exposure range. Furthermore, the readout was reasonably rapid (10 ms for pixel discharge). The proposed detector allows readout of half a pixel row at a time (odd pixels followed by even pixels), thus permitting the readout of a complete image in 30 s for a 40 cm x 40 cm detector with the potential of reducing that time by using greater readout light intensity. This demonstrates that a-Se based x-ray detectors using photoconductively activated switches could form a basis for a practical integrated digital radiography system.

Continuously-Variable Positive-Mesh Power Transmission

NASA Technical Reports Server (NTRS)

Johnson, J. L.

1982-01-01

Proposed transmission with continuously-variable speed ratio couples two mechanical trigonometric-function generators. Transmission is expected to handle higher loads than conventional variable-pulley drives; and, unlike variable pulley, positive traction through entire drive train with no reliance on friction to transmit power. Able to vary speed continuously through zero and into reverse. Possible applications in instrumentation where drive-train slippage cannot be tolerated.

Progress on the FDM Development at SRON: Toward 160 Pixels

NASA Astrophysics Data System (ADS)

den Hartog, R. H.; Bruijn, M. P.; Clenet, A.; Gottardi, L.; Hijmering, R.; Jackson, B. D.; van der Kuur, J.; van Leeuwen, B. J.; van der Linden, A. J.; van Loon, D.; Nieuwenhuizen, A.; Ridder, M.; van Winden, P.

2014-08-01

SRON is developing the electronic read-out for arrays of transition edge sensors using frequency domain multiplexing in combination with base-band feedback. The astronomical applications of this system are the read-out of soft X-ray micro-calorimeters in a potential instrument on the European X-ray mission-under-study Athena+ and far-IR bolometers for the Safari instrument on the Japanese mission SPICA. In this paper we demonstrate the simultaneous read-out of 38 bolometer pixels at a 12 aW/Hz dark NEP level. The stability of the read-out is assessed over 400 s. time spans. Although some 1/f noise is present, there are several bolometers for which 1/f-free read-out can be demonstrated.

Simulation of dental collisions and occlusal dynamics in the virtual environment.

PubMed

Stavness, I K; Hannam, A G; Tobias, D L; Zhang, X

2016-04-01

Semi-adjustable articulators have often been used to simulate occlusal dynamics, but advances in intra-oral scanning and computer software now enable dynamics to be modelled mathematically. Computer simulation of occlusal dynamics requires accurate virtual casts, records to register them and methods to handle mesh collisions during movement. Here, physical casts in a semi-adjustable articulator were scanned with a conventional clinical intra-oral scanner. A coordinate measuring machine was used to index their positions in intercuspation, protrusion, right and left laterotrusion, and to model features of the articulator. Penetrations between the indexed meshes were identified and resolved using restitution forces, and the final registrations were verified by distance measurements between dental landmarks at multiple sites. These sites were confirmed as closely approximating via measurements made from homologous transilluminated vinylpolysiloxane interocclusal impressions in the mounted casts. Movements between the indexed positions were simulated with two models in a custom biomechanical software platform. In model DENTAL, 6 degree-of-freedom movements were made to minimise deviation from a straight line path and also shaped by dynamic mesh collisions detected and resolved mathematically. In model ARTIC, the paths were further constrained by surfaces matching the control settings of the articulator. Despite these differences, the lower mid-incisor point paths were very similar in both models. The study suggests that mathematical simulation utilising interocclusal 'bite' registrations can closely replicate the primary movements of casts mounted in a semi-adjustable articulator. Additional indexing positions and appropriate software could, in some situations, replace the need for mechanical semi-adjustable articulation and/or its virtual representation. © 2015 John Wiley & Sons Ltd.

Compact and portable X-ray imager system using Medipix3RX

NASA Astrophysics Data System (ADS)

Garcia-Nathan, T. B.; Kachatkou, A.; Jiang, C.; Omar, D.; Marchal, J.; Changani, H.; Tartoni, N.; van Silfhout, R. G.

2017-10-01

In this paper the design and implementation of a novel portable X-ray imager system is presented. The design features a direct X-ray detection scheme by making use of a hybrid detector (Medipix3RX). Taking advantages of the capabilities of the Medipix3RX, like a high resolution, zero dead-time, single photon detection and charge-sharing mode, the imager has a better resolution and higher sensitivity compared to using traditional indirect detection schemes. A detailed description of the system is presented, which consists of a vacuum chamber containing the sensor, an electronic board for temperature management, conditioning and readout of the sensor and a data processing unit which also handles network connection and allow communication with clients by acting as a server. A field programmable gate array (FPGA) device is used to implement the readout protocol for the Medipix3RX, apart from the readout the FPGA can perform complex image processing functions such as feature extraction, histogram, profiling and image compression at high speeds. The temperature of the sensor is monitored and controlled through a PID algorithm making use of a Peltier cooler, improving the energy resolution and response stability of the sensor. Without implementing data compression techniques, the system is capable of transferring 680 profiles/s or 240 images/s in a continuous mode. Implementation of equalization procedures and tests on colour mode are presented in this paper. For the experimental measurements the Medipix3RX sensor was used with a Silicon layer. One of the tested applications of the system is as an X-ray beam position monitor (XBPM) device for synchrotron applications. The XBPM allows a non-destructive real time measurement of the beam position, size and intensity. A Kapton foil is placed in the beam path scattering radiation towards a pinhole camera setup that allows the sensor to obtain an image of the beam. By using profiles of the synchrotron X-ray beam, high frequency movement of the beam position can be studied, up to 340 Hz. The system is capable of realizing an independent energy measure of the beam by using the Medipix3RX variable energy threshold feature.

X-ray imaging using amorphous selenium: photoinduced discharge (PID) readout for digital general radiography.

PubMed

Rowlands, J A; Hunter, D M

1995-12-01

Digital radiographic systems based on photoconductive layers with the latent charge image readout by photoinduced discharge (PID) are investigated theoretically. Previously, a number of different systems have been proposed using sandwiched photoconductor and insulator layers and readout using a scanning laser beam. These systems are shown to have the general property of being very closely coupled (i.e., optimization of one imaging characteristic usually impacts negatively on others). The presence of a condensed state insulator between the photoconductor surface and the readout electrode does, however, confer a great advantage over systems using air gaps with their relatively low breakdown field. The greater breakdown field of condensed state dielectrics permits the modification of the electric field during the period between image formation and image readout. The trade-off between readout speed and noise makes this system suitable for instant general radiography and even rapid sequence radiography, however, the system is unsuitable for the low exposure rates used in fluoroscopy.

Investigation of Readout RF Pulse Impact on the Chemical Exchange Saturation Transfer Spectrum

PubMed Central

Huang, Sheng-Min; Jan, Meei-Ling; Liang, Hsin-Chin; Chang, Chia-Hao; Wu, Yi-Chun; Tsai, Shang-Yueh; Wang, Fu-Nien

2015-01-01

Chemical exchange saturation transfer magnetic resonance imaging (CEST-MRI) is capable of both microenvironment and molecular imaging. The optimization of scanning parameters is important since the CEST effect is sensitive to factors such as saturation power and field homogeneity. The aim of this study was to determine if the CEST effect would be altered by changing the length of readout RF pulses. Both theoretical computer simulation and phantom experiments were performed to examine the influence of readout RF pulses. Our results showed that the length of readout RF pulses has unremarkable impact on the Z-spectrum and CEST effect in both computer simulation and phantom experiment. Moreover, we demonstrated that multiple refocusing RF pulses used in rapid acquisition with relaxation enhancement (RARE) sequence induced no obvious saturation transfer contrast. Therefore, readout RF pulse has negligible effect on CEST Z-spectrum and the optimization of readout RF pulse length can be disregarded in CEST imaging protocol. PMID:26455576

Image charge multi-role and function detectors

NASA Astrophysics Data System (ADS)

Milnes, James; Lapington, Jon S.; Jagutzki, Ottmar; Howorth, Jon

2009-06-01

The image charge technique used with microchannel plate imaging tubes provides several operational and practical benefits by serving to isolate the electronic image readout from the detector. The simple dielectric interface between detector and readout provides vacuum isolation and no vacuum electrical feed-throughs are required. Since the readout is mechanically separate from the detector, an image tube of generic design can be simply optimised for various applications by attaching it to different readout devices and electronics. We present imaging performance results using a single image tube with a variety of readout devices suited to differing applications: (a) A four electrode charge division tetra wedge anode, optimised for best spatial resolution in photon counting mode. (b) A cross delay line anode, enabling higher count rate, and the possibility of discriminating near co-incident events, and an event timing resolution of better than 1 ns. (c) A multi-anode readout connected, either to a multi-channel oscilloscope for analogue measurements of fast optical pulses, or alternately, to a multi-channel time correlated single photon counting (TCSPC) card.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dragone, A; /SLAC; Pratte, J.F.

An ASIC for the readout of signals from X-ray Active Matrix Pixel Sensor (XAMPS) detectors to be used at the Linac Coherent Light Source (LCLS) is presented. The X-ray Pump Probe (XPP) instrument, for which the ASIC has been designed, requires a large input dynamic range on the order of 104 photons at 8 keV with a resolution of half a photon FWHM. Due to the size of the pixel and the length of the readout line, large input capacitance is expected, leading to stringent requirement on the noise optimization. Furthermore, the large number of pixels needed for a goodmore » position resolution and the fixed LCLS beam period impose limitations on the time available for the single pixel readout. Considering the periodic nature of the LCLS beam, the ASIC developed for this application is a time-variant system providing low-noise charge integration, filtering and correlated double sampling. In order to cope with the large input dynamic range a charge pump scheme implementing a zero-balance measurement method has been introduced. It provides an on chip 3-bit coarse digital conversion of the integrated charge. The residual charge is sampled using correlated double sampling into analog memory and measured with the required resolution. The first 64 channel prototype of the ASIC has been fabricated in TSMC CMOS 0.25 {micro}m technology. In this paper, the ASIC architecture and performances are presented.« less

Optical tomographic memories: algorithms for the efficient information readout

NASA Astrophysics Data System (ADS)

Pantelic, Dejan V.

1990-07-01

Tomographic alogithms are modified in order to reconstruct the inf ormation previously stored by focusing laser radiation in a volume of photosensitive media. Apriori information about the position of bits of inf ormation is used. 1. THE PRINCIPLES OF TOMOGRAPHIC MEMORIES Tomographic principles can be used to store and reconstruct the inf ormation artificially stored in a bulk of a photosensitive media 1 The information is stored by changing some characteristics of a memory material (e. g. refractive index). Radiation from the two independent light sources (e. g. lasers) is f ocused inside the memory material. In this way the intensity of the light is above the threshold only in the localized point where the light rays intersect. By scanning the material the information can be stored in binary or nary format. When the information is stored it can be read by tomographic methods. However the situation is quite different from the classical tomographic problem. Here a lot of apriori information is present regarding the p0- sitions of the bits of information profile representing single bit and a mode of operation (binary or n-ary). 2. ALGORITHMS FOR THE READOUT OF THE TOMOGRAPHIC MEMORIES Apriori information enables efficient reconstruction of the memory contents. In this paper a few methods for the information readout together with the simulation results will be presented. Special attention will be given to the noise considerations. Two different

Splitter board for steamer tube readout at the SLD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bacchetta, N.; Bisello, D.; Castro, A.

1989-10-01

This paper presents a controller board designed as a part of the data acquisition system for the readout of limited streamer tube strips in the warm iron calorimeter for the SLD detector. The board controls the data readout and allows for remote setting and diagnostic of the system.

InSb arrays with CCD readout for 1.0- to 5.5-microns infrared applications

NASA Technical Reports Server (NTRS)

Phillips, J. D.; Scorso, J. B.; Thom, R. D.

1976-01-01

There were two approaches for fabricating indium antimonide (InSb) arrays with CCD readout discussed. The hybrid approach integrated InSb detectors and silicon CCDs in a modular assembly via an advanced interconnection technology. In the monolithic approach, the InSb infrared detectors and the CCD readout were integrated on the same InSb chip. Both approaches utilized intrinsic (band-to-band) photodetection with the attendant advantages over extrinsic detectors. The status of each of these detector readout concepts, with pertinent performance characteristics, was presented.

The IBL readout system

NASA Astrophysics Data System (ADS)

Dopke, J.; Falchieri, D.; Flick, T.; Gabrielli, A.; Kugel, A.; Mättig, P.; Morettini, P.; Polini, A.; Schroer, N.

2011-01-01

The first upgrade for the ATLAS Pixel Detector will be an additional layer, which is called IBL (Insertable B-Layer). To readout this new layer, built from new electronics, an update of the readout electronics is necessary. The aim is to develop a system which is capable to read out at a higher bandwidth, but also compatible with the existing system to be integrated into it. This paper describes the necessary development to reach a new readout system, concentrating on the requirements of a newly designed Back of Crate card as the optical interface in the counting room.

An encoding readout method used for Multi-gap Resistive Plate Chambers (MRPCs) for muon tomography

NASA Astrophysics Data System (ADS)

Yue, X.; Zeng, M.; Wang, Y.; Wang, X.; Zeng, Z.; Zhao, Z.; Cheng, J.

2014-09-01

A muon tomography facility has been built in Tsinghua University. Because of the low flux of cosmic muon, an encoding readout method, based on the fine-fine configuration, was implemented for the 2880 channels induced signals from the Multi-gap Resistive Plate Chamber (MRPC) detectors. With the encoding method, the number of the readout electronics was dramatically reduced and thus the complexity and the cost of the facility was reduced, too. In this paper, the details of the encoding method, and the overall readout system setup in the muon tomography facility are described. With the commissioning of the facility, the readout method works well. The spatial resolution of all MRPC detectors are measured with cosmic muon and the preliminary imaging result are also given.

Ionisation density effects following optical excitation in LiF:Mg, Ti (TLD-100).

PubMed

Weiss, D; Horowitz, Y; Oster, L

2007-01-01

The TL signal following 5 eV photon excitation of previously irradiated and readout material has been studied as a function of ionisation density and various experimental parameters: (i) maximum temperature of the first readout; (ii) photon fluence; (iii) photon energy and (iv) beta ray dose. Following alpha particle irradiation, the ratio of the second-readout to first-readout TL signal, epsilon(alpha,) has been found to be 10-20 times higher than that following beta irradiation, indicative of the possibility of using the double ratio epsilon(alpha)/epsilon(beta) as a mixed-field discriminator. The beginning of an attempt to explain this unusual effect is offered in the framework of the track structure theory and kinetic modelling of the beta ray dose-response of the first and second readouts.

Detuned surface plasmon resonance scattering of gold nanorods for continuous wave multilayered optical recording and readout.

PubMed

Taylor, Adam B; Kim, Jooho; Chon, James W M

2012-02-27

In a multilayered structure of absorptive optical recording media, continuous-wave laser operation is highly disadvantageous due to heavy beam extinction. For a gold nanorod based recording medium, the narrow surface plasmon resonance (SPR) profile of gold nanorods enables the variation of extinction through mulilayers by a simple detuning of the readout wavelength from the SPR peak. The level of signal extinction through the layers can then be greatly reduced, resulting more efficient readout at deeper layers. The scattering signal strength may be decreased at the detuned wavelength, but balancing these two factors results an optimal scattering peak wavelength that is specific to each layer. In this paper, we propose to use detuned SPR scattering from gold nanorods as a new mechanism for continuous-wave readout scheme on gold nanorod based multilayered optical storage. Using this detuned scattering method, readout using continuous-wave laser is demonstrated on a 16 layer optical recording medium doped with heavily distributed, randomly oriented gold nanorods. Compared to SPR on-resonant readout, this method reduced the required readout power more than one order of magnitude, with only 60 nm detuning from SPR peak. The proposed method will be highly beneficial to multilayered optical storage applications as well as applications using a continuous medium doped heavily with plasmonic nanoparticles.

Recent developments for the upgrade of the LHCb readout system

NASA Astrophysics Data System (ADS)

Cachemiche, J. P.; Y Duval, P.; Hachon, F.; Le Gac, R.; Réthoré, F.

2013-02-01

The upgraded LHCb readout system aims at a trigger-free readout of the entire detector at the bunch-crossing rate. This implies a major architectural change for the readout system that must capture the data at 40 MHz instead of 1 MHz. One of the key components of this upgrade system is the readout board. The LHCb collaboration has chosen to evaluate the ATCA architecture as form-factor for the readout board. The readout system architecture relies on a unique board able to satisfy all the requirements for data transmission, timing and fast control as well as experiment control system. A generic ATCA carrier board has been developped. It is equipped with four dense AMC mezzanines able to interface a total of 144 bidirectional optical links at up to 10 Gbits/s. This board embeds 4 high end Stratix V GX devices for data processing and a programmable set of commutation functions allowing to reconfigure the connectivity of the system in a flexible way. The overall architecture will be presented and how the cards map over each functionality. First results and measurements will be described in particular those related to the use of new highly integrated optical devices. At last we will present the incremental development methodology used in this project.

High accuracy position response calibration method for a micro-channel plate ion detector

NASA Astrophysics Data System (ADS)

Hong, R.; Leredde, A.; Bagdasarova, Y.; Fléchard, X.; García, A.; Müller, P.; Knecht, A.; Liénard, E.; Kossin, M.; Sternberg, M. G.; Swanson, H. E.; Zumwalt, D. W.

2016-11-01

We have developed a position response calibration method for a micro-channel plate (MCP) detector with a delay-line anode position readout scheme. Using an in situ calibration mask, an accuracy of 8 μm and a resolution of 85 μm (FWHM) have been achieved for MeV-scale α particles and ions with energies of ∼10 keV. At this level of accuracy, the difference between the MCP position responses to high-energy α particles and low-energy ions is significant. The improved performance of the MCP detector can find applications in many fields of AMO and nuclear physics. In our case, it helps reducing systematic uncertainties in a high-precision nuclear β-decay experiment.

Transfer and alignment of random single-walled carbon nanotube films by contact printing.

PubMed

Liu, Huaping; Takagi, Daisuke; Chiashi, Shohei; Homma, Yoshikazu

2010-02-23

We present a simple method to transfer large-area random single-walled carbon nanotube (SWCNT) films grown on SiO(2) substrates onto another surface through a simple contact printing process. The transferred random SWCNT films can be assembled into highly ordered, dense regular arrays with high uniformity and reproducibility by sliding the growth substrate during the transfer process. The position of the transferred SWCNT film can be controlled by predefined patterns on the receiver substrates. The process is compatible with a variety of substrates, and even metal meshes for transmission electron microscopy (TEM) can be used as receiver substrates. Thus, suspended web-like SWCNT networks and aligned SWCNT arrays can be formed over the grids of TEM meshes, so that the structures of the transferred SWCNTs can be directly observed by TEM. This simple technique can be used to controllably transfer SWCNTs for property studies, for the fabrication of devices, or even as support films for TEM meshes.

EMPHASIS/Nevada UTDEM user guide. Version 2.0.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, C. David; Seidel, David Bruce; Pasik, Michael Francis

The Unstructured Time-Domain ElectroMagnetics (UTDEM) portion of the EMPHASIS suite solves Maxwell's equations using finite-element techniques on unstructured meshes. This document provides user-specific information to facilitate the use of the code for applications of interest. UTDEM is a general-purpose code for solving Maxwell's equations on arbitrary, unstructured tetrahedral meshes. The geometries and the meshes thereof are limited only by the patience of the user in meshing and by the available computing resources for the solution. UTDEM solves Maxwell's equations using finite-element method (FEM) techniques on tetrahedral elements using vector, edge-conforming basis functions. EMPHASIS/Nevada Unstructured Time-Domain ElectroMagnetic Particle-In-Cell (UTDEM PIC) ismore » a superset of the capabilities found in UTDEM. It adds the capability to simulate systems in which the effects of free charge are important and need to be treated in a self-consistent manner. This is done by integrating the equations of motion for macroparticles (a macroparticle is an object that represents a large number of real physical particles, all with the same position and momentum) being accelerated by the electromagnetic forces upon the particle (Lorentz force). The motion of these particles results in a current, which is a source for the fields in Maxwell's equations.« less

Hiatal hernia repair with gore bio-a tissue reinforcement: our experience.

PubMed

Antonino, Agrusa; Giorgio, Romano; Giuseppe, Frazzetta; Giovanni, De Vita; Silvia, Di Giovanni; Daniela, Chianetta; Giuseppe, Di Buono; Vincenzo, Sorce; Gaspare, Gulotta

2014-01-01

Type I hiatal hernia is associated with gastroesophageal reflux disease (GERD) in 50-90% of cases. Several trials strongly support surgery as an effective alternative to medical therapy. Today, laparoscopic fundoplication is considered as the procedure of choice. However, primary laparoscopic hiatal hernia repair is associated with upto 42% recurrence rate. Mesh reinforcement of the crural closure decreases the recurrence but can lead to complications, above all nonabsorbable ones. We experiment a new totally absorbable mesh by Gore. Case. We present a case of a 65-year-old female patient with a 6-year classic history of GERD. Endoscopy revealed a large hiatal hernia and esophagitis. pH study was positive for acid reflux; esophageal manometry revealed LES intrathoracic dislocation. With laparoscopic approach, the hiatal hernia defect was identified and primarily repaired, by crural closure. Gore Bio-A Tissue Reinforcement was trimmed to fit the defect accommodating the esophagus. Nissen fundoplication was performed. Result. Bio-A mesh was easily placed laparoscopically. It has good handling and could be cut and tailored intraoperatively for optimal adaptation. There were no short-term complications. Conclusion. Crural closure reinforcement can be done readily with this new totally absorbable mesh replaced by soft tissue over six months. However, further data and studies are needed to evaluate long-term outcomes.

Hiatal Hernia Repair with Gore Bio-A Tissue Reinforcement: Our Experience

PubMed Central

Antonino, Agrusa; Giorgio, Romano; Giuseppe, Frazzetta; Giovanni, De Vita; Silvia, Di Giovanni; Daniela, Chianetta; Giuseppe, Di Buono; Vincenzo, Sorce; Gaspare, Gulotta

2014-01-01

Type I hiatal hernia is associated with gastroesophageal reflux disease (GERD) in 50–90% of cases. Several trials strongly support surgery as an effective alternative to medical therapy. Today, laparoscopic fundoplication is considered as the procedure of choice. However, primary laparoscopic hiatal hernia repair is associated with upto 42% recurrence rate. Mesh reinforcement of the crural closure decreases the recurrence but can lead to complications, above all nonabsorbable ones. We experiment a new totally absorbable mesh by Gore. Case. We present a case of a 65-year-old female patient with a 6-year classic history of GERD. Endoscopy revealed a large hiatal hernia and esophagitis. pH study was positive for acid reflux; esophageal manometry revealed LES intrathoracic dislocation. With laparoscopic approach, the hiatal hernia defect was identified and primarily repaired, by crural closure. Gore Bio-A Tissue Reinforcement was trimmed to fit the defect accommodating the esophagus. Nissen fundoplication was performed. Result. Bio-A mesh was easily placed laparoscopically. It has good handling and could be cut and tailored intraoperatively for optimal adaptation. There were no short-term complications. Conclusion. Crural closure reinforcement can be done readily with this new totally absorbable mesh replaced by soft tissue over six months. However, further data and studies are needed to evaluate long-term outcomes. PMID:24864221

Multi-dimensional Upwind Fluctuation Splitting Scheme with Mesh Adaption for Hypersonic Viscous Flow. Degree awarded by Virginia Polytechnic Inst. and State Univ., 9 Nov. 2001

NASA Technical Reports Server (NTRS)

Wood, William A., III

2002-01-01

A multi-dimensional upwind fluctuation splitting scheme is developed and implemented for two-dimensional and axisymmetric formulations of the Navier-Stokes equations on unstructured meshes. Key features of the scheme are the compact stencil, full upwinding, and non-linear discretization which allow for second-order accuracy with enforced positivity. Throughout, the fluctuation splitting scheme is compared to a current state-of-the-art finite volume approach, a second-order, dual mesh upwind flux difference splitting scheme (DMFDSFV), and is shown to produce more accurate results using fewer computer resources for a wide range of test cases. A Blasius flat plate viscous validation case reveals a more accurate upsilon-velocity profile for fluctuation splitting, and the reduced artificial dissipation production is shown relative to DMFDSFV. Remarkably, the fluctuation splitting scheme shows grid converged skin friction coefficients with only five points in the boundary layer for this case. The second half of the report develops a local, compact, anisotropic unstructured mesh adaptation scheme in conjunction with the multi-dimensional upwind solver, exhibiting a characteristic alignment behavior for scalar problems. The adaptation strategy is extended to the two-dimensional and axisymmetric Navier-Stokes equations of motion through the concept of fluctuation minimization.

Design issues of a low cost lock-in amplifier readout circuit for an infrared detector

NASA Astrophysics Data System (ADS)

Scheepers, L.; Schoeman, J.

2014-06-01

In the past, high resolution thermal sensors required expensive cooling techniques making the early thermal imagers expensive to operate and cumbersome to transport, limiting them mainly to military applications. However, the introduction of uncooled microbolometers has overcome many of earlier problems and now shows great potential for commercial optoelectric applications. The structure of uncooled microbolometer sensors, especially their smaller size, makes them attractive in low cost commercial applications requiring high production numbers with relatively low performance requirements. However, the biasing requirements of these microbolometers cause these sensors to generate a substantial amount of noise on the output measurements due to self-heating. Different techniques to reduce this noise component have been attempted, such as pulsed biasing currents and the use of blind bolometers as common mode reference. These techniques proved to either limit the performance of the microbolometer or increase the cost of their implementation. The development of a low cost lock-in amplifier provides a readout technique to potentially overcome these challenges. High performance commercial lock-in amplifiers are very expensive. Using this as a readout circuit for a microbolometer will take away from the low manufacturing cost of the detector array. Thus, the purpose of this work was to develop a low cost readout circuit using the technique of phase sensitive detection and customizing this as a readout circuit for microbolometers. The hardware and software of the readout circuit was designed and tested for improvement of the signal-to-noise ratio (SNR) of the microbolometer signal. An optical modulation system was also developed in order to effectively identify the desired signal from the noise with the use of the readout circuit. A data acquisition and graphical user interface sub system was added in order to display the signal recovered by the readout circuit. The readout circuit was able to enhance the SNR of the microbolometer signal significantly. It was shown that the quality of the phase sensitive detector plays a significant role in the effectiveness of the readout circuit to improve the SNR.

Treatment of calvarial defects by resorbable and non-resorbable sonic activated polymer pins and mouldable titanium mesh in two dogs: a case report.

PubMed

Langer, Pierre; Black, Cameron; Egan, Padraig; Fitzpatrick, Noel

2018-06-22

To date, calvarial defects in dogs have traditionally been addressed with different types of implants including bone allograft, polymethylmethacrylate and titanium mesh secured with conventional metallic fixation methods. This report describes the use of an absorbable and non absorbable novel polymer fixation method, Bonewelding® technology, in combination with titanium mesh for the repair of calvarial defects in two dogs. The clinical outcomes and comparative complication using resorbable and non-resorbable thermoplastic pins were compared. This report of two cases documents the repair of a traumatic calvarial fracture in an adult male Greyhound and a cranioplasty following frontal bone tumor resection in an adult female Cavalier King Charles Spaniel with the use of a commercially available titanium mesh secured with an innovative thermoplastic polymer screw system (Bonewelding®). The treatment combination aimed to restore cranial structure, sinus integrity and cosmetic appearance. A mouldable titanium mesh was cut to fit the bone defect of the frontal bone and secured with either resorbable or non-resorbable polymer pins using Bonewelding® technology. Gentamycin-impregnated collagen sponge was used intraoperatively to assist with sealing of the frontal sinuses. Calvarial fracture and post-operative implant positioning were advised using computed tomography. A satisfactory restoration of skull integrity and cosmetic result was achieved, and long term clinical outcome was deemed clinically adequate with good patient quality of life. Postoperative complications including rostral mesh uplift with minor associated clinical signs were encountered when resorbable pins were used. No postoperative complications were experienced in non-resorbable pins at 7 months follow-up, by contrast mesh uplift was noted 3 weeks post-procedure in the case treated using absorbable pins. The report demonstrates the innovative use of sonic-activated polymer pins (Bonewelding® technology) alongside titanium mesh is a suitable alternative technique for skull defect repair in dogs. The use of Bonewelding® may offer advantages in reduction of surgical time. Further, ultrasonic pin application may be less invasive than alternative metallic fixation and potentially reduces bone trauma. Polymer systems may offer enhanced mesh-bone integration when compared to traditional metallic implants. The use of polymer pins demonstrates initial potential as a fixation method in cranioplasty. Initial findings in a single case comparison indicate a possible advantage in the use of non-absorbable over the absorbable systems to circumvent complications associated with variable polymer degradation, further long term studies with higher patient numbers are required before reliable conclusions can be made.

CMOS Active-Pixel Image Sensor With Intensity-Driven Readout

NASA Technical Reports Server (NTRS)

Langenbacher, Harry T.; Fossum, Eric R.; Kemeny, Sabrina

1996-01-01

Proposed complementary metal oxide/semiconductor (CMOS) integrated-circuit image sensor automatically provides readouts from pixels in order of decreasing illumination intensity. Sensor operated in integration mode. Particularly useful in number of image-sensing tasks, including diffractive laser range-finding, three-dimensional imaging, event-driven readout of sparse sensor arrays, and star tracking.

Comparison of two optimized readout chains for low light CIS

NASA Astrophysics Data System (ADS)

Boukhayma, A.; Peizerat, A.; Dupret, A.; Enz, C.

2014-03-01

We compare the noise performance of two optimized readout chains that are based on 4T pixels and featuring the same bandwidth of 265kHz (enough to read 1Megapixel with 50frame/s). Both chains contain a 4T pixel, a column amplifier and a single slope analog-to-digital converter operating a CDS. In one case, the pixel operates in source follower configuration, and in common source configuration in the other case. Based on analytical noise calculation of both readout chains, an optimization methodology is presented. Analytical results are confirmed by transient simulations using 130nm process. A total input referred noise bellow 0.4 electrons RMS is reached for a simulated conversion gain of 160μV/e-. Both optimized readout chains show the same input referred 1/f noise. The common source based readout chain shows better performance for thermal noise and requires smaller silicon area. We discuss the possible drawbacks of the common source configuration and provide the reader with a comparative table between the two readout chains. The table contains several variants (column amplifier gain, in-pixel transistor sizes and type).

RF Single Electron Transistor Readout Amplifiers for Superconducting Astronomical Detectors for X-Ray to Sub-mm Wavelengths

NASA Technical Reports Server (NTRS)

Stevenson, Thomas; Aassime, Abdelhanin; Delsing, Per; Frunzio, Luigi; Li, Li-Qun; Prober, Daniel; Schoelkopf, Robert; Segall, Ken; Wilson, Chris; Stahle, Carl

2000-01-01

We report progress on using a new type of amplifier, the Radio-Frequency Single-Electron Transistor (RF-SET), to develop multi-channel sensor readout systems for fast and sensitive readout of high impedance cryogenic photodetectors such as Superconducting Tunnel Junctions and Single Quasiparticle Photon Counters. Although cryogenic, these detectors are desirable because of capabilities not other-wise attainable. However, high impedances and low output levels make low-noise, high-speed readouts challenging, and large format arrays would be facilitated by compact, low-power, on-chip integrated amplifiers. Well-suited for this application are RF-SETs, very high performance electrometers which use an rf readout technique to provide 100 MHz bandwidth. Small size, low power, and cryogenic operation allow direct integration with detectors, and using multiple rf carrier frequencies permits simultaneous readout of 20-50 amplifiers with a common electrical connection. We describe both the first 2-channel demonstration of this wavelength division multiplexing technique for RF-SETs, and Charge-Locked-Loop operation with 100 kHz of closed-loop bandwidth.

Light-Sharing Interface for dMiCE Detectors Using Sub-Surface Laser Engraving

PubMed Central

Hunter, William C. J.; Miyaoka, Robert S.; MacDonald, Lawrence; McDougald, Wendy; Lewellen, Thomas K.

2015-01-01

We have previously reported on dMiCE, a method of resolving depth or interaction (DOI) in a pair of discrete crystals by encoding light sharing properties as a function of depth in the interface of a crystal-element pair. A challenge for this method is the cost and repeatability of interface treatment for each crystal pair. In this work, we report our preliminary results on using sub-surface laser engraving (SSLE) as a means of forming this depth-dependent interface in a dMiCE detector. A surplus first-generation SSLE system was used to create a partially reflective layer 100-microns thick at the boundary between two halves of a 1.4-by-2.9-by-20 mm3 LYSO crystal. The boundary of these paired crystal elements was positioned between two 3-mm wide Silicon photomultiplier arrays. The responses of these two photodetectors were acquired for an ensemble of 511-keV photons collimated to interact at a fixed depth in just one crystal element. Interaction position was then varied to measure detector response as a function of depth, which was then used to maximum-likelihood positions. Despite use of sub-optimal SSLE processing we found an average DOI resolution of 3.4 mm for front-sided readout and 3.9 mm for back-sided readout while obtaining energy resolutions on the order of 10%. We expect DOI resolution can be improved significantly by optimizing the SSLE process and pattern. PMID:25914421

Light-Sharing Interface for dMiCE Detectors using Sub-Surface Laser Engraving.

PubMed

Hunter, William C J; Miyaoka, Robert S; MacDonald, Lawrence; McDougald, Wendy; Lewellen, Thomas K

2013-10-01

We have previously reported on dMiCE, a method of resolving depth or interaction (DOI) in a pair of discrete crystals by encoding light sharing properties as a function of depth in the interface of this crystal-element pair. A challenge for this method is the cost and repeatability of interface treatment for a crystal pair. In this work, we report our preliminary results on using sub-surface laser engraving (SSLE) as a means of forming this depth-dependent interface in a dMiCE detector. A surplus first-generation SSLE system was used to create a partially reflective layer 100-microns thick at the boundary between two halves of a 1.4-by-2.9-by-20 mmˆ3 LYSO crystal. The boundary of these paired crystal elements was positioned between two 3-mm wide Geiger-Müller avalanche photodiodes from Hamamatsu. The responses of these two photodetectors were acquired for an ensemble of 511-keV photons collimated to interact at a fixed depth in just one crystal element. Interaction position was then varied to measure detector response as a function of depth, which was then used to maximum-likelihood positions events. Despite use of sub-optimal SSLE processing we found an average DOI resolution of 3.4 mm for front-sided readout and 3.9 mm for back-sided readout. We expect DOI resolution can be improved significantly by optimizing the SSLE process and pattern.

Light-Sharing Interface for dMiCE Detectors using Sub-Surface Laser Engraving

PubMed Central

Hunter, William C.J.; Miyaoka, Robert S.; MacDonald, Lawrence; McDougald, Wendy; Lewellen, Thomas K.

2014-01-01

We have previously reported on dMiCE, a method of resolving depth or interaction (DOI) in a pair of discrete crystals by encoding light sharing properties as a function of depth in the interface of this crystal-element pair. A challenge for this method is the cost and repeatability of interface treatment for a crystal pair. In this work, we report our preliminary results on using sub-surface laser engraving (SSLE) as a means of forming this depth-dependent interface in a dMiCE detector. A surplus first-generation SSLE system was used to create a partially reflective layer 100-microns thick at the boundary between two halves of a 1.4-by-2.9-by-20 mmˆ3 LYSO crystal. The boundary of these paired crystal elements was positioned between two 3-mm wide Geiger-Müller avalanche photodiodes from Hamamatsu. The responses of these two photodetectors were acquired for an ensemble of 511-keV photons collimated to interact at a fixed depth in just one crystal element. Interaction position was then varied to measure detector response as a function of depth, which was then used to maximum-likelihood positions events. Despite use of sub-optimal SSLE processing we found an average DOI resolution of 3.4 mm for front-sided readout and 3.9 mm for back-sided readout. We expect DOI resolution can be improved significantly by optimizing the SSLE process and pattern. PMID:25506194

Light-Sharing Interface for dMiCE Detectors Using Sub-Surface Laser Engraving.

PubMed

Hunter, William C J; Miyaoka, Robert S; MacDonald, Lawrence; McDougald, Wendy; Lewellen, Thomas K

2015-02-06

We have previously reported on dMiCE, a method of resolving depth or interaction (DOI) in a pair of discrete crystals by encoding light sharing properties as a function of depth in the interface of a crystal-element pair. A challenge for this method is the cost and repeatability of interface treatment for each crystal pair. In this work, we report our preliminary results on using sub-surface laser engraving (SSLE) as a means of forming this depth-dependent interface in a dMiCE detector. A surplus first-generation SSLE system was used to create a partially reflective layer 100-microns thick at the boundary between two halves of a 1.4-by-2.9-by-20 mm 3 LYSO crystal. The boundary of these paired crystal elements was positioned between two 3-mm wide Silicon photomultiplier arrays. The responses of these two photodetectors were acquired for an ensemble of 511-keV photons collimated to interact at a fixed depth in just one crystal element. Interaction position was then varied to measure detector response as a function of depth, which was then used to maximum-likelihood positions. Despite use of sub-optimal SSLE processing we found an average DOI resolution of 3.4 mm for front-sided readout and 3.9 mm for back-sided readout while obtaining energy resolutions on the order of 10%. We expect DOI resolution can be improved significantly by optimizing the SSLE process and pattern.

An FPGA-Based Real-Time Maximum Likelihood 3D Position Estimation for a Continuous Crystal PET Detector

NASA Astrophysics Data System (ADS)

Wang, Yonggang; Xiao, Yong; Cheng, Xinyi; Li, Deng; Wang, Liwei

2016-02-01

For the continuous crystal-based positron emission tomography (PET) detector built in our lab, a maximum likelihood algorithm adapted for implementation on a field programmable gate array (FPGA) is proposed to estimate the three-dimensional (3D) coordinate of interaction position with the single-end detected scintillation light response. The row-sum and column-sum readout scheme organizes the 64 channels of photomultiplier (PMT) into eight row signals and eight column signals to be readout for X- and Y-coordinates estimation independently. By the reference events irradiated in a known oblique angle, the probability density function (PDF) for each depth-of-interaction (DOI) segment is generated, by which the reference events in perpendicular irradiation are assigned to DOI segments for generating the PDFs for X and Y estimation in each DOI layer. Evaluated by the experimental data, the algorithm achieves an average X resolution of 1.69 mm along the central X-axis, and DOI resolution of 3.70 mm over the whole thickness (0-10 mm) of crystal. The performance improvements from 2D estimation to the 3D algorithm are also presented. Benefiting from abundant resources of FPGA and a hierarchical storage arrangement, the whole algorithm can be implemented into a middle-scale FPGA. By a parallel structure in pipelines, the 3D position estimator on the FPGA can achieve a processing throughput of 15 M events/s, which is sufficient for the requirement of real-time PET imaging.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giraldo, L. Ocampo; Bolotnikov, A. E.; Camarda, G. S.

For this study, we evaluated the X-Y position resolution achievable in 3D pixelated detectors by processing the signal waveforms readout from neighboring pixels. In these measurements we used a focused light beam, down to 10 μm, generated by a ~1 mW pulsed laser (650 nm) to carry out raster scans over selected 3×3 pixel areas, while recording the charge signals from the 9 pixels and the cathode using two synchronized digital oscilloscopes.

Scanning instrumentation for measuring magnetic field trapping in high Tc superconductors

NASA Technical Reports Server (NTRS)

Sisk, R. C.; Helton, A. J.

1993-01-01

Computerized scanning instrumentation measures and displays trapped magnetic fields across the surface of high Tc superconductors at 77 K. Data are acquired in the form of a raster scan image utilizing stepping motor stages for positioning and a cryogenic Hall probe for magnetic field readout. Flat areas up to 45 mm in diameter are scanned with 0.5-mm resolution and displayed as false color images.

The ATLAS Liquid Argon Electromagnetic Calorimeter

NASA Astrophysics Data System (ADS)

Carminati, L.

2005-10-01

The construction of the ATLAS Liquid Argon Electromagnetic calorimeter has been completed and commissioning is in progress. After a brief description of the detector layout, readout electronics and calibration, a review of the present status of the integration and the detector qualification is reported. Finally a selection of performance results obtained during several test beams will be presented with particular attention to linearity, uniformity, position reconstruction and γ/π0 separation.

ClotChip: A Microfluidic Dielectric Sensor for Point-of-Care Assessment of Hemostasis.

PubMed

Maji, Debnath; Suster, Michael A; Kucukal, Erdem; Sekhon, Ujjal D S; Gupta, Anirban Sen; Gurkan, Umut A; Stavrou, Evi X; Mohseni, Pedram

2017-12-01

This paper describes the design, fabrication, and testing of a microfluidic sensor for dielectric spectroscopy of human whole blood during coagulation. The sensor, termed ClotChip, employs a three-dimensional, parallel-plate, capacitive sensing structure with a floating electrode integrated into a microfluidic channel. Interfaced with an impedance analyzer, the ClotChip measures the complex relative dielectric permittivity, ϵ r , of human whole blood in the frequency range of 40 Hz to 100 MHz. The temporal variation in the real part of the blood dielectric permittivity at 1 MHz features a time to reach a permittivity peak, , as well as a maximum change in permittivity after the peak, , as two distinct parameters of ClotChip readout. The ClotChip performance was benchmarked against rotational thromboelastometry (ROTEM) to evaluate the clinical utility of its readout parameters in capturing the clotting dynamics arising from coagulation factors and platelet activity. exhibited a very strong positive correlation ( r = 0.99, p < 0.0001) with the ROTEM clotting time parameter, whereas exhibited a strong positive correlation (r = 0.85,  p < 0.001) with the ROTEM maximum clot firmness parameter. This paper demonstrates the ClotChip potential as a point-of-care platform to assess the complete hemostatic process using <10 μL of human whole blood.

Direct measurement of the Goos-Hänchen shift using a scanning quadrant detector and a polarization maintaining fiber.

PubMed

Yallapragada, Venkata Jayasurya; Mulay, Gajendra L; Rao, Ch N; Ravishankar, Ajith P; Achanta, Venu Gopal

2016-10-01

High precision measurements of optical beam shifts are important in various fields including sensing, atomic force microscopy, and measuring beam shifts at interfaces. Sub-micron shifts are generally measured by indirect techniques such as weak measurements. We demonstrate a straightforward and robust measurement scheme for the shift, based on a scanning quadrant photodiode (QPD) that is biased using a low noise electronic circuit. The shift is measured with respect to a reference beam that is co-propagating with the signal beam. Thus, the shift of the signal beam is readout directly as the difference between the x-intercepts of the QPD scan plot of the signal and reference beams versus the position of the detector. To measure the beam shift, we use polarization multiplexing scheme where the p-polarized signal and s-polarized reference beams are modulated at two different frequencies and co-launched into a polarization-maintaining fiber. Both the signal and reference beam positions are readout by two lock-in amplifiers simultaneously. In order to demonstrate the utility of this method, we perform a direct measurement of Goos-Hänchen shift of a beam that is reflected from a plane gold surface. Accuracy of 150 nm is achieved using this technique.

Direct measurement of the Goos-Hänchen shift using a scanning quadrant detector and a polarization maintaining fiber

NASA Astrophysics Data System (ADS)

Yallapragada, Venkata Jayasurya; Mulay, Gajendra L.; Rao, Ch. N.; Ravishankar, Ajith P.; Achanta, Venu Gopal

2016-10-01

High precision measurements of optical beam shifts are important in various fields including sensing, atomic force microscopy, and measuring beam shifts at interfaces. Sub-micron shifts are generally measured by indirect techniques such as weak measurements. We demonstrate a straightforward and robust measurement scheme for the shift, based on a scanning quadrant photodiode (QPD) that is biased using a low noise electronic circuit. The shift is measured with respect to a reference beam that is co-propagating with the signal beam. Thus, the shift of the signal beam is readout directly as the difference between the x-intercepts of the QPD scan plot of the signal and reference beams versus the position of the detector. To measure the beam shift, we use polarization multiplexing scheme where the p-polarized signal and s-polarized reference beams are modulated at two different frequencies and co-launched into a polarization-maintaining fiber. Both the signal and reference beam positions are readout by two lock-in amplifiers simultaneously. In order to demonstrate the utility of this method, we perform a direct measurement of Goos-Hänchen shift of a beam that is reflected from a plane gold surface. Accuracy of 150 nm is achieved using this technique.

Development of new anatomy reconstruction software to localize cardiac isochrones to the cardiac surface from the 12 lead ECG.

PubMed

van Dam, Peter M; Gordon, Jeffrey P; Laks, Michael M; Boyle, Noel G

2015-01-01

Non-invasive electrocardiographic imaging (ECGI) of the cardiac muscle can help the pre-procedure planning of the ablation of ventricular arrhythmias by reducing the time to localize the origin. Our non-invasive ECGI system, the cardiac isochrone positioning system (CIPS), requires non-intersecting meshes of the heart, lungs and torso. However, software to reconstruct the meshes of the heart, lungs and torso with the capability to check and prevent these intersections is currently lacking. Consequently the reconstruction of a patient specific model with realistic atrial and ventricular wall thickness and incorporating blood cavities, lungs and torso usually requires additional several days of manual work. Therefore new software was developed that checks and prevents any intersections, and thus enables the use of accurate reconstructed anatomical models within CIPS. In this preliminary study we investigated the accuracy of the created patient specific anatomical models from MRI or CT. During the manual segmentation of the MRI data the boundaries of the relevant tissues are determined. The resulting contour lines are used to automatically morph reference meshes of the heart, lungs or torso to match the boundaries of the morphed tissue. Five patients were included in the study; models of the heart, lungs and torso were reconstructed from standard cardiac MRI images. The accuracy was determined by computing the distance between the segmentation contours and the morphed meshes. The average accuracy of the reconstructed cardiac geometry was within 2mm with respect to the manual segmentation contours on the MRI images. Derived wall volumes and left ventricular wall thickness were within the range reported in literature. For each reconstructed heart model the anatomical heart axis was computed using the automatically determined anatomical landmarks of the left apex and the mitral valve. The accuracy of the reconstructed heart models was well within the accuracy of the used medical image data (pixel size <1.5mm). For the lungs and torso the number of triangles in the mesh was reduced, thus decreasing the accuracy of the reconstructed mesh. A novel software tool has been introduced, which is able to reconstruct accurate cardiac anatomical models from MRI or CT within only a few hours. This new anatomical reconstruction tool might reduce the modeling errors within the cardiac isochrone positioning system and thus enable the clinical application of CIPS to localize the PVC/VT focus to the ventricular myocardium from only the standard 12 lead ECG. Copyright © 2015 Elsevier Inc. All rights reserved.

Using a pulsed laser beam to investigate the feasibility of sub-pixel position resolution with time-correlated transient signals in 3D pixelated CdZnTe detectors

DOE PAGES

Giraldo, L. Ocampo; Bolotnikov, A. E.; Camarda, G. S.; ...

2017-04-20

For this study, we evaluated the X-Y position resolution achievable in 3D pixelated detectors by processing the signal waveforms readout from neighboring pixels. In these measurements we used a focused light beam, down to 10 μm, generated by a ~1 mW pulsed laser (650 nm) to carry out raster scans over selected 3×3 pixel areas, while recording the charge signals from the 9 pixels and the cathode using two synchronized digital oscilloscopes.

A radiation-tolerant electronic readout system for portal imaging

NASA Astrophysics Data System (ADS)

Östling, J.; Brahme, A.; Danielsson, M.; Iacobaeus, C.; Peskov, V.

2004-06-01

A new electronic portal imaging device, EPID, is under development at the Karolinska Institutet and the Royal Institute of Technology. Due to considerable demands on radiation tolerance in the radiotherapy environment, a dedicated electronic readout system has been designed. The most interesting aspect of the readout system is that it allows to read out ˜1000 pixels in parallel, with all electronics placed outside the radiation beam—making the detector more radiation resistant. In this work we are presenting the function of a small prototype (6×100 pixels) of the electronic readout board that has been tested. Tests were made with continuous X-rays (10-60 keV) and with α particles. The results show that, without using an optimised gas mixture and with an early prototype only, the electronic readout system still works very well.

On the Stiffness of the Mesh and Urethral Mobility: A Finite Element Analysis.

PubMed

Brandão, Sofia; Parente, Marco; Da Roza, Thuane Huyer; Silva, Elisabete; Ramos, Isabel Maria; Mascarenhas, Teresa; Natal Jorge, Renato Manuel

2017-08-01

Midurethral slings are used to correct urethral hypermobility in female stress urinary incontinence (SUI), defined as the complaint of involuntary urine leakage when the intra-abdominal pressure (IAP) is increased. Structural and thermal features influence their mechanical properties, which may explain postoperative complications, e.g., erosion and urethral obstruction. We studied the effect of the mesh stiffness on urethral mobility at Valsalva maneuver, under impairment of the supporting structures (levator ani and/or ligaments), by using a numerical model. For that purpose, we modeled a sling with "lower" versus "higher" stiffness and evaluated the mobility of the bladder and urethra, that of the urethrovesical junction (the α-angle), and the force exerted at the fixation of the sling. The effect of impaired levator ani or pubourethral ligaments (PUL) alone on the organs displacement and α-angle opening was similar, showing their important role together on urethral stabilization. When the levator ani and all the ligaments were simulated as impaired, the descent of the bladder and urethra went up to 25.02 mm, that of the bladder neck was 14.57 mm, and the α-angle was 129.7 deg, in the range of what was found in women with SUI. Both meshes allowed returning to normal positioning, although at the cost of higher force exerted by the mesh with higher stiffness (3.4 N against 2.3 N), which can relate to tissue erosion. This finite element analysis allowed mimicking the biomechanical response of the pelvic structures in response to changing a material property of the midurethral synthetic mesh.

Fibrin sealant for mesh fixation in laparoscopic umbilical hernia repair: 1-year results of a randomized controlled double-blinded study.

PubMed

Eriksen, J R; Bisgaard, T; Assaadzadeh, S; Jorgensen, L N; Rosenberg, J

2013-08-01

Fibrin sealant for mesh fixation has significant positive effects on early outcome after laparoscopic ventral hernia repair (LVHR) compared with titanium tacks. Whether fibrin sealant fixation also results in better long-term outcome is unknown. We performed a randomized controlled trial including patients with umbilical hernia defects from 1.5 to 5 cm at three Danish hernia centres. We used a 12 cm circular mesh. Participants were randomized to fibrin sealant or titanium tack fixation. Patients were seen in the outpatient clinic at 1 and 12 months follow-up. Forty patients were included of whom 34 were available for intention to treat analysis after 1 year. There were no significant differences in pain, discomfort, fatigue, satisfaction or quality of life between the two groups at the 1-year follow-up. Five patients (26 %) in the fibrin sealant group and one (6 %) in the tack group were diagnosed with a recurrence at the 1-year follow-up (p = 0.182) (overall recurrence rate 17 %). Hernia defects in patients with recurrence were significantly larger than in those without recurrence (median 4.0 vs. 2.8 cm, p = 0.009). Patients with larger hernia defects and fibrin sealant mesh fixation had higher recurrence rates than expected, although the study was not powered for assessment of recurrence. There was no significant difference between groups in any parameters after the 1-year follow-up. The beneficial effects of mesh fixation with fibrin sealant on early outcome warrant further studies on optimization of the surgical technique to prevent recurrence.

Note: Readout of a micromechanical magnetometer for the ITER fusion reactor.

PubMed

Rimminen, H; Kyynäräinen, J

2013-05-01

We present readout instrumentation for a MEMS magnetometer, placed 30 m away from the MEMS element. This is particularly useful when sensing is performed in high-radiation environment, where the semiconductors in the readout cannot survive. High bandwidth transimpedance amplifiers are used to cancel the cable capacitances of several nanofarads. A frequency doubling readout scheme is used for crosstalk elimination. Signal-to-noise ratio in the range of 60 dB was achieved and with sub-percent nonlinearity. The presented instrument is intended for the steady-state magnetic field measurements in the ITER fusion reactor.

ALICE inner tracking system readout electronics prototype testing with the CERN "Giga Bit Transceiver''

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schambach, Joachim; Rossewij, M. J.; Sielewicz, K. M.

The ALICE Collaboration is preparing a major detector upgrade for the LHC Run 3, which includes the construction of a new silicon pixel based Inner Tracking System (ITS). The ITS readout system consists of 192 readout boards to control the sensors and their power system, receive triggers, and deliver sensor data to the DAQ. To prototype various aspects of this readout system, an FPGA based carrier board and an associated FMC daughter card containing the CERN Gigabit Transceiver (GBT) chipset have been developed. Furthermore, this contribution describes laboratory and radiation testing results with this prototype board set.

ALICE inner tracking system readout electronics prototype testing with the CERN "Giga Bit Transceiver''

DOE PAGES

Schambach, Joachim; Rossewij, M. J.; Sielewicz, K. M.; ...

2016-12-28

The ALICE Collaboration is preparing a major detector upgrade for the LHC Run 3, which includes the construction of a new silicon pixel based Inner Tracking System (ITS). The ITS readout system consists of 192 readout boards to control the sensors and their power system, receive triggers, and deliver sensor data to the DAQ. To prototype various aspects of this readout system, an FPGA based carrier board and an associated FMC daughter card containing the CERN Gigabit Transceiver (GBT) chipset have been developed. Furthermore, this contribution describes laboratory and radiation testing results with this prototype board set.

Prototype readout electronics and silicon strip detector study for the silicon tracking system at compressed baryonic matter experiment

NASA Astrophysics Data System (ADS)

Kasiński, Krzysztof; Szczygieł, Robert; Gryboś, Paweł

2011-10-01

This paper presents the prototype detector readout electronics for the STS (Silicon Tracking System) at CBM (Compressed Baryonic Matter) experiment at FAIR, GSI (Helmholtzzentrum fuer Schwerionenforschung GmbH) in Germany. The emphasis has been put on the strip detector readout chip and its interconnectivity with detector. Paper discusses the impact of the silicon strip detector and interconnection cable construction on the overall noise of the system and architecture of the TOT02 readout ASIC. The idea and problems of the double-sided silicon detector usage are also presented.

Cavity-Enhanced Optical Readout of a Single Solid-State Spin

NASA Astrophysics Data System (ADS)

Sun, Shuo; Kim, Hyochul; Solomon, Glenn S.; Waks, Edo

2018-05-01

We demonstrate optical readout of a single spin using cavity quantum electrodynamics. The spin is based on a single trapped electron in a quantum dot that has a poor branching ratio of 0.43. Selectively coupling one of the optical transitions of the quantum dot to the cavity mode results in a spin-dependent cavity reflectivity that enables spin readout by monitoring the reflected intensity of an incident optical field. Using this approach, we demonstrate spin-readout fidelity of 0.61. Achieving this fidelity using resonance fluorescence from a bare dot would require 43 times improvement in photon collection efficiency.

Simultaneous single-shot readout of multi-qubit circuits using a traveling-wave parametric amplifier

NASA Astrophysics Data System (ADS)

O'Brien, Kevin

Observing and controlling the state of ever larger quantum systems is critical for advancing quantum computation. Utilizing a Josephson traveling wave parametric amplifier (JTWPA), we demonstrate simultaneous multiplexed single shot readout of 10 transmon qubits in a planar architecture. We employ digital image sideband rejection to eliminate noise at the image frequencies. We quantify crosstalk and infidelity due to simultaneous readout and control of multiple qubits. Based on current amplifier technology, this approach can scale to simultaneous readout of at least 20 qubits. This work was supported by the Army Research Office.

ALICE inner tracking system readout electronics prototype testing with the CERN ``Giga Bit Transceiver''

NASA Astrophysics Data System (ADS)

Schambach, J.; Rossewij, M. J.; Sielewicz, K. M.; Aglieri Rinella, G.; Bonora, M.; Ferencei, J.; Giubilato, P.; Vanat, T.

2016-12-01

The ALICE Collaboration is preparing a major detector upgrade for the LHC Run 3, which includes the construction of a new silicon pixel based Inner Tracking System (ITS). The ITS readout system consists of 192 readout boards to control the sensors and their power system, receive triggers, and deliver sensor data to the DAQ. To prototype various aspects of this readout system, an FPGA based carrier board and an associated FMC daughter card containing the CERN Gigabit Transceiver (GBT) chipset have been developed. This contribution describes laboratory and radiation testing results with this prototype board set.

University of Florida Torsion Pendulum for Testing Key LISA Technology

NASA Astrophysics Data System (ADS)

Apple, Stephen; Chilton, Andrew; Olatunde, Taiwo Janet; Hillsberry, Daniel; Parry, Samantha; Ciani, Giacomo; Wass, Peter; Mueller, Guido; Conklin, John

2018-01-01

This presentation will describe the design and performance of a new torsion pendulum at the University of Florida used for testing inertial sensors and associated technologies for use in space – based gravitational wave observatories and geodesy missions. In particular this new torsion pendulum facility is testing inertial sensors and associated technology for the upcoming LISA (laser interferometer space antenna) space-based gravitational wave observatory mission. The torsion pendulum apparatus is comprised of a suspended cross bar assembly that has LISA test mass mockups at each of its ends. Two of the test mass mockups are enclosed by capacitive sensors which provide actuation and position sensing. The entire assembly is housed in a vacuum chamber. The pendulum cross-bar converts rotational motion of the test masses about the suspension fiber axis into translational motion. The 22 cm cross bar arm length along with the extremely small torsional spring constant of the suspension fiber results in a near free fall condition in the translational degree-of-freedom orthogonal to both the member and the suspension fiber. The test masses are electrically isolated from the pendulum assembly and their charge is controlled via photoemission using fiber coupled UV LEDS. Position of the test masses is measured using both capacitive and interferometric readout. The broadband sensitivity of the capacitive readout and laser interferometer readout is 30 nm/√Hz and 0.5 nm/√Hz respectively. The performance of the pendulum measured in equivalent acceleration noise acting on a LISA test mass is approximately 3 × 10-13 ms-2/√Hz at 2 mHz. This presentation will also discuss the design and fabrication of a flight-like gravitational reference sensor that will soon be integrated into the torsion pendulum facility. This flight-like GRS will allow for noise performance measurements in a more LISA-like configuration.

Calibration of large area Micromegas detectors using cosmic rays

NASA Astrophysics Data System (ADS)

Biebel, O.; Flierl, B.; Herrmann, M.; Hertenberger, R.; Klitzner, F.; Lösel, P.; Müller, R.; Valderanis, C.; Zibell, A.

2017-06-01

Currently m2-sized micropattern detectors with spatial resolution better than 100 μm and online trigger capability are of big interest for many experiments. Large size in combination with superb spatial resolution and trigger capability implicates that the construction of these detectors is highly sophisticated and imposes strict mechanical tolerances. We developed a method to survey assembled and working detectors on potential deviations of the micro pattern readout structures from design value as well as deformations of the whole detector, using cosmic muons in a tracking facility. The LMU Cosmic Ray Facility consists of two 8 m2 ATLAS Monitored Drift Tube chambers (MDT) for precision muon reference tracking and two segmented trigger hodoscopes with sub-ns time-resolution and additional 10 cm position information along the wires of the MDTs. It provides information on homogeneity in efficiency and pulse height of one or several micropattern detectors installed in between the MDTs. With an angular acceptance of -30° to +30° the comparison of the reference muon tracking with centroidal position determination or time projection chamber like track reconstruction in the micropattern detector allows for calibration in three dimensions. We present results of a m2-sized one-dimensional resistive strip Micromegas detector consisting of two readout boards with in total 2048 strips, read out by 16 APV25 front-end boards. This 16-fold segmentation along the precision direction in combination with a 10-fold segmentation in orthogonal direction by the resolution of the trigger hodoscope, allows for very detailed analysis of the 1 m2 detector under study by subdivision into 160 partitions, each being analyzed separately. We are able to disentangle deviations from the readout strip straightness and global deformation due to the small overpressure caused by the Ar:CO2 (93:7) gas mixture flux. We introduce the alignment and calibration procedure, report on homogeneity in efficiency and pulse height and present results on deformation and performance of the m2-sized Micromegas.

First human use of hybrid synthetic/biologic mesh in ventral hernia repair: a multicenter trial.

PubMed

Bittner, James G; El-Hayek, Kevin; Strong, Andrew T; LaPinska, Melissa Phillips; Yoo, Jin S; Pauli, Eric M; Kroh, Matthew

2018-03-01

Mesh options for reinforcement of ventral/incisional hernia (VIH) repair include synthetic or biologic materials. While each material has known advantages and disadvantages, little is understood about outcomes when these materials are used in combination. This multicenter study reports on the first human use of a novel synthetic/biologic hybrid mesh (Zenapro ® Hybrid Hernia Repair Device) for VIH repair. This prospective, multicenter post-market clinical trial enrolled consecutive adults who underwent elective VIH repair with hybrid mesh placed in the intraperitoneal or retromuscular/preperitoneal position. Patients were classified as Ventral Hernia Working Group (VHWG) grades 1-3 and had clean or clean-contaminated wounds. Outcomes of ventral and incisional hernia were compared using appropriate parametric tests. In all, 63 patients underwent VIH repair with hybrid mesh. Most were females (54.0%), had a mean age of 54.8 ± 10.9 years and mean body mass index of 34.5 ± 7.8 kg/m 2 , and classified as VHWG grade 2 (87.3%). Most defects were midline (92.1%) with a mean area of 106 ± 155 cm 2 . Cases were commonly classified as clean (92.1%) and were performed laparoscopically (60.3%). Primary fascial closure was achieved in 82.5% with 28.2% requiring component separation. Mesh location was frequently intraperitoneal (69.8%). Overall, 39% of patients available for follow-up at 12 months suffered surgical site events, which were generally more frequent after incisional hernia repair. Of these, seroma (23.7%) was most common, but few (8.5%) required procedural intervention. Other surgical site events that required procedural intervention included hematoma (1.7%), wound dehiscence (1.7%), and surgical site infection (3.4%). Recurrence rate was 6.8% (95% CI 2.2-16.6%) at 12-months postoperatively. Zenapro ® Hybrid Hernia Repair Device is safe and effective in VHWG grade 1-2 patients with clean wounds out to 12 months. Short-term outcomes and recurrence rate are acceptable. This hybrid mesh represents a novel option for reinforcement during VIH repair.

Design and evaluation of a SiPM-based large-area detector module for positron emission imaging

NASA Astrophysics Data System (ADS)

Alva-Sánchez, H.; Murrieta-Rodríguez, T.; Calva-Coraza, E.; Martínez-Dávalos, A.; Rodríguez-Villafuerte, M.

2018-03-01

The design and evaluation of a large-area detector module for positron emission imaging applications, is presented. The module features a SensL ArrayC-60035-64P-PCB solid state detector (8×8 array of tileable silicon photomultipliers by SensL, 7.2 mm pitch) covering a total area of 57.4×57.4 mm2. The detector module was formed using a pixelated array of 40×40 lutetium-yttrium oxyorthosilicate (LYSO) scintillator crystal elements with 1.43 mm pitch. A 7 mm thick coupling light guide was used to allow light sharing between adjacent SiPM. A 16-channel symmetric charge division (SCD) readout board was designed to multiplex the number of signals from 64 to 16 (8 columns and 8 rows) and a center-of-gravity algorithm to identify the position. Data acquisition and digitization was accomplished using a custom-made system based on FPGAs boards. Crystal maps were obtained using 18F-positron sources and Voronoi diagrams were used to correct for geometric distortions and to generate a non-uniformity correction matrix. All measurements were taken at a controlled room temperature of 22oC. The crystal maps showed minor distortion, 90% of the 1600 total crystal elements could be identified, a mean peak-to-valley ratio of 4.3 was obtained and a 10.8% mean energy resolution for 511 keV annihilation photons was determined. The performance of the detector using our own readout board was compared to that using two different commercially readout boards using the same detector module arrangement. We show that these large-area SiPM arrays, combined with a 16-channel SCD readout board, can offer high spatial resolution, excellent energy resolution and detector uniformity and thus, can be used for positron emission imaging applications.

Read-out electronics for DC squid magnetic measurements

DOEpatents

Ganther, Jr., Kenneth R.; Snapp, Lowell D.

2002-01-01

Read-out electronics for DC SQUID sensor systems, the read-out electronics incorporating low Johnson noise radio-frequency flux-locked loop circuitry and digital signal processing algorithms in order to improve upon the prior art by a factor of at least ten, thereby alleviating problems caused by magnetic interference when operating DC SQUID sensor systems in magnetically unshielded environments.

Quantum nondemolition readout using a Josephson bifurcation amplifier

NASA Astrophysics Data System (ADS)

Boulant, N.; Ithier, G.; Meeson, P.; Nguyen, F.; Vion, D.; Esteve, D.; Siddiqi, I.; Vijay, R.; Rigetti, C.; Pierre, F.; Devoret, M.

2007-07-01

We report an experiment on the determination of the quantum nondemolition (QND) nature of a readout scheme of a quantum electrical circuit. The circuit is a superconducting quantum bit measured by microwave reflectometry using a Josephson bifurcation amplifier. We perform a series of two subsequent measurements, record their values and correlation, and quantify the QND character of this readout.

Readout systems for inner detectors at the LHC and SLHC

NASA Astrophysics Data System (ADS)

Issever, Cigdem

2006-12-01

A general overview of the optoelectronic readout and control systems of the ATLAS and CMS inner detectors is given. The talk will also cover challenges and issues of future optoelectronic readout systems at the upgraded LHC (SLHC). First results of radiation tests of VCSELs and optical fibres which were irradiated up to SLHC fluences will be presented.

Time-gated detection of protein-protein interactions with transcriptional readout

PubMed Central

Sanchez, Mateo I; Coukos, Robert; von Zastrow, Mark

2017-01-01

Transcriptional assays, such as yeast two-hybrid and TANGO, that convert transient protein-protein interactions (PPIs) into stable expression of transgenes are powerful tools for PPI discovery, screens, and analysis of cell populations. However, such assays often have high background and lose information about PPI dynamics. We have developed SPARK (Specific Protein Association tool giving transcriptional Readout with rapid Kinetics), in which proteolytic release of a membrane-tethered transcription factor (TF) requires both a PPI to deliver a protease proximal to its cleavage peptide and blue light to uncage the cleavage site. SPARK was used to detect 12 different PPIs in mammalian cells, with 5 min temporal resolution and signal ratios up to 37. By shifting the light window, we could reconstruct PPI time-courses. Combined with FACS, SPARK enabled 51 fold enrichment of PPI-positive over PPI-negative cells. Due to its high specificity and sensitivity, SPARK has the potential to advance PPI analysis and discovery. PMID:29189201

Tri-linear color multi-linescan sensor with 200 kHz line rate

NASA Astrophysics Data System (ADS)

Schrey, Olaf; Brockherde, Werner; Nitta, Christian; Bechen, Benjamin; Bodenstorfer, Ernst; Brodersen, Jörg; Mayer, Konrad J.

2016-11-01

In this paper we present a newly developed linear CMOS high-speed line-scanning sensor realized in a 0.35 μm CMOS OPTO process for line-scan with 200 kHz true RGB and 600 kHz monochrome line rate, respectively. In total, 60 lines are integrated in the sensor allowing for electronic position adjustment. The lines are read out in rolling shutter manner. The high readout speed is achieved by a column-wise organization of the readout chain. At full speed, the sensor provides RGB color images with a spatial resolution down to 50 μm. This feature enables a variety of applications like quality assurance in print inspection, real-time surveillance of railroad tracks, in-line monitoring in flat panel fabrication lines and many more. The sensor has a fill-factor close to 100%, preventing aliasing and color artefacts. Hence the tri-linear technology is robust against aliasing ensuring better inspection quality and thus less waste in production lines.

Coupling a single electron spin to a microwave resonator: Part I: controlling transverse and longitudinal couplings

NASA Astrophysics Data System (ADS)

Lachance-Quirion, Dany; Beaudoin, Félix; Camirand Lemyre, Julien; Coish, William A.; Pioro-Ladrière, Michel

Novel quantum technologies can be combined within hybrid systems to benefit from the complementary capabilities of individual components. For example, microwave-frequency superconducting resonators are ideally suited to perform qubit readout and to mediate two-qubit gates, while spin qubits offer long coherence times and high-fidelity single-qubit gates. In this talk, we consider strong coupling between a microwave resonator and an electron-spin qubit in a double quantum dot due to an inhomogeneous magnetic field generated by a nearby nanomagnet.. Considering realistic parameters, we estimate spin-resonator couplings of order 1 MHz. Further, we show that the position of the double dot relative to the nanomagnet allows us to select between purely longitudinal and transverse couplings. While the transverse coupling may be used for quantum state transfer between the spin qubit and the resonator, the longitudinal coupling could be used in a new qubit readout scheme recently introduced for superconducting qubits.

A split band-Cholesky equation solving strategy for finite element analysis of transient field problems. [in fluid mechanics

NASA Technical Reports Server (NTRS)

Cooke, C. H.

1978-01-01

The paper describes the split-Cholesky strategy for banded matrices arising from the large systems of equations in certain fluid mechanics problems. The basic idea is that for a banded matrix the computation can be carried out in pieces, with only a small portion of the matrix residing in core. Mesh considerations are discussed by demonstrating the manner in which the assembly of finite element equations proceeds for linear trial functions on a triangular mesh. The FORTRAN code which implements the out-of-core decomposition strategy for banded symmetric positive definite matrices (mass matrices) of a coupled initial value problem is given.

Unification of some advection schemes in two dimensions

NASA Technical Reports Server (NTRS)

Sidilkover, D.; Roe, P. L.

1995-01-01

The relationship between two approaches towards construction of genuinely two-dimensional upwind advection schemes is established. One of these approaches is of the control volume type applicable on structured cartesian meshes. It resulted in the compact high resolution schemes capable of maintaining second order accuracy in both homogeneous and inhomogeneous cases. Another one is the fluctuation splitting approach, which is well suited for triangular (and possibly) unstructured meshes. Understanding the relationship between these two approaches allows us to formulate here a new fluctuation splitting high resolution (i.e. possible use of artificial compression, while maintaining positivity property) scheme. This scheme is shown to be linearity preserving in inhomogeneous as well as homogeneous cases.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sackett, S.J.

JASON solves general electrostatics problems having either slab or cylindrical symmetry. More specifically, it solves the self-adjoint elliptic equation, div . (KgradV) - ..gamma..V + rho = 0 in an aritrary two-dimensional domain. For electrostatics, V is the electrostatic potential, K is the dielectric tensor, and rho is the free-charge density. The parameter ..gamma.. is identically zero for electrostatics but may have a positive nonzero value in other cases (e.g., capillary surface problems with gravity loading). The system of algebraic equations used in JASON is generated by the finite element method. Four-node quadrilateral elements are used for most of themore » mesh. Triangular elements, however, are occasionally used on boundaries to avoid severe mesh distortions. 15 figures. (RWR)« less

The earliest herbivorous marine reptile and its remarkable jaw apparatus.

PubMed

Chun, Li; Rieppel, Olivier; Long, Cheng; Fraser, Nicholas C

2016-05-01

Newly discovered fossils of the Middle Triassic reptile Atopodentatus unicus call for a radical reassessment of its feeding behavior. The skull displays a pronounced hammerhead shape that was hitherto unknown. The long, straight anterior edges of both upper and lower jaws were lined with batteries of chisel-shaped teeth, whereas the remaining parts of the jaw rami supported densely packed needle-shaped teeth forming a mesh. The evidence indicates a novel feeding mechanism wherein the chisel-shaped teeth were used to scrape algae off the substrate, and the plant matter that was loosened was filtered from the water column through the more posteriorly positioned tooth mesh. This is the oldest record of herbivory within marine reptiles.

Primary task event-related potentials related to different aspects of information processing

NASA Technical Reports Server (NTRS)

Munson, Robert C.; Horst, Richard L.; Mahaffey, David L.

1988-01-01

The results of two studies which investigated the relationships between cognitive processing and components of transient event-related potentials (ERPs) are presented in a task in which mental workload was manipulated. The task involved the monitoring of an array of discrete readouts for values that went out of bounds, and was somewhat analogous to tasks performed in cockpits. The ERPs elicited by the changing readouts varied with the number of readouts being monitored, the number of monitored readouts that were close to going out of bounds, and whether or not the change took a monitored readout out of bounds. Moreover, different regions of the waveform differentially reflected these effects. The results confirm the sensitivity of scalp-recorded ERPs to the cognitive processes affected by mental workload and suggest the possibility of extracting useful ERP indices of primary task performance in a wide range of man-machine settings.

TES Detector Noise Limited Readout Using SQUID Multiplexers

NASA Technical Reports Server (NTRS)

Staguhn, J. G.; Benford, D. J.; Chervenak, J. A.; Khan, S. A.; Moseley, S. H.; Shafer, R. A.; Deiker, S.; Grossman, E. N.; Hilton, G. C.; Irwin, K. D.

2004-01-01

The availability of superconducting Transition Edge Sensors (TES) with large numbers of individual detector pixels requires multiplexers for efficient readout. The use of multiplexers reduces the number of wires needed between the cryogenic electronics and the room temperature electronics and cuts the number of required cryogenic amplifiers. We are using an 8 channel SQUID multiplexer to read out one-dimensional TES arrays which are used for submillimeter astronomical observations. We present results from test measurements which show that the low noise level of the SQUID multiplexers allows accurate measurements of the TES Johnson noise, and that in operation, the readout noise is dominated by the detector noise. Multiplexers for large number of channels require a large bandwidth for the multiplexed readout signal. We discuss the resulting implications for the noise performance of these multiplexers which will be used for the readout of two dimensional TES arrays in next generation instruments.

Microwave SQUID Multiplexer for the Readout of Metallic Magnetic Calorimeters

NASA Astrophysics Data System (ADS)

Kempf, S.; Gastaldo, L.; Fleischmann, A.; Enss, C.

2014-06-01

We have realized a frequency-domain multiplexing technique for the readout of large metallic magnetic calorimeter detector arrays. It is based on non-hysteretic single-junction SQUIDs and allows for a simultaneous readout of hundreds or thousands of detectors by using a single cryogenic high electron mobility transistor amplifier and two coaxial cables that are routed from room-temperature to the detector array. We discuss the working principle of the multiplexer and present details about our prototype multiplexer design. We show that fabricated devices are fully operational and that characteristic SQUID parameters such as the input sensitivity of the SQUID or the resonance frequency of the readout circuit can be predicted with confidence. Our best device so far has shown a magnetic flux white noise level of 1.4 m which can in future be reduced by an optimization of the fabrication processes as well as an improved microwave readout system.

Focal plane infrared readout circuit with automatic background suppression

NASA Technical Reports Server (NTRS)

Pain, Bedabrata (Inventor); Yang, Guang (Inventor); Sun, Chao (Inventor); Shaw, Timothy J. (Inventor); Wrigley, Chris J. (Inventor)

2002-01-01

A circuit for reading out a signal from an infrared detector includes a current-mode background-signal subtracting circuit having a current memory which can be enabled to sample and store a dark level signal from the infrared detector during a calibration phase. The signal stored by the current memory is subtracted from a signal received from the infrared detector during an imaging phase. The circuit also includes a buffered direct injection input circuit and a differential voltage readout section. By performing most of the background signal estimation and subtraction in a current mode, a low gain can be provided by the buffered direct injection input circuit to keep the gain of the background signal relatively small, while a higher gain is provided by the differential voltage readout circuit. An array of such readout circuits can be used in an imager having an array of infrared detectors. The readout circuits can provide a high effective handling capacity.

On the dynamic readout characteristic of nonlinear super-resolution optical storage

NASA Astrophysics Data System (ADS)

Wei, Jingsong

2013-03-01

Researchers have developed nonlinear super-resolution optical storage for the past twenty years. However, several concerns remain, including (1) the presence of readout threshold power; (2) the increase of threshold power with the reduction of the mark size, and (3) the increase of the carrier-to-noise ratio (CNR) at the initial stage and then decrease with the increase of readout laser power or laser irradiation time. The present work calculates and analyzes the super-resolution spot formed by the thin film masks and the readout threshold power characteristic according to the derived formula and based on the nonlinear saturable absorption characteristic and threshold of structural change. The obtained theoretical calculation and experimental data answer the concerns regarding the dynamic readout threshold characteristic and CNR dependence on laser power and irradiation time. The near-field optical spot scanning experiment further verifies the super-resolution spot formation produced through the nonlinear thin film masks.

A PCIe Gen3 based readout for the LHCb upgrade

NASA Astrophysics Data System (ADS)

Bellato, M.; Collazuol, G.; D'Antone, I.; Durante, P.; Galli, D.; Jost, B.; Lax, I.; Liu, G.; Marconi, U.; Neufeld, N.; Schwemmer, R.; Vagnoni, V.

2014-06-01

The architecture of the data acquisition system foreseen for the LHCb upgrade, to be installed by 2018, is devised to readout events trigger-less, synchronously with the LHC bunch crossing rate at 40 MHz. Within this approach the readout boards act as a bridge between the front-end electronics and the High Level Trigger (HLT) computing farm. The baseline design for the LHCb readout is an ATCA board requiring dedicated crates. A local area standard network protocol is implemented in the on-board FPGAs to read out the data. The alternative solution proposed here consists in building the readout boards as PCIe peripherals of the event-builder servers. The main architectural advantage is that protocol and link-technology of the event-builder can be left open until very late, to profit from the most cost-effective industry technology available at the time of the LHC LS2.

Analysis of read-out heating rate effects on the glow peaks of TLD-100 using WinGCF software

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauk, Sabar, E-mail: sabar@usm.my; Hussin, Siti Fatimah; Alam, Md. Shah

This study was done to analyze the effects of the read-out heating rate on the LiF:Mg,Ti (TLD-100) thermoluminescent dosimeters (TLD) glow peaks using WinGCF computer software. The TLDs were exposed to X-ray photons with a potential difference of 72 kVp and 200 mAs in air and were read-out using a Harshaw 3500 TLD reader. The TLDs were read-out using four read-out heating rates at 10, 7, 4 and 1 °C s{sup −1}. It was observed that lowering the heating rate could separate more glow peaks. The activation energy for peak 5 was found to be lower than that for peakmore » 4. The peak maximum temperature and the integral value of the main peak decreased as the heating rate decreases.« less

Grid Effects on LES Thermo-Acoustic Limit-Cycle of a Full Annular Aeronautical Engine

NASA Astrophysics Data System (ADS)

Wolf, Pierre; Gicquel, Laurent Y. M.; Staffelbach, Gabriel; Poinsot, Thierry

Recent developments in large scale computer architectures allow Large Eddy Simulation (LES) to be considered for the prediction of turbulent reacting flows in geometries encountered in industry. To do so, various difficulties must be overcome and the first one is to ensure that proper meshes can be used for LES. Indeed, the quality of meshes is known to be a critical factor in LES of reacting flows. This issue becomes even more crucial when LES is used to compute large configurations such as full annular combustion chambers. Various analysis of mesh effects on LES results have been published before but all are limited to single-sector computational domains. However, real annular gas-turbine engines contain ten to twenty of such sectors and LES must also be used in such full chambers for the study of ignition or azimuthal thermo-acoustic interactions. Instabilities (mostly azimuthal modes involving the full annular geometry) remain a critical issue to aeronautical or power-generation industries and LES seems to be a promising path to properly apprehend such complex unsteady couplings. Based on these observations, mesh effects on LES in a full annular gas-turbine combustion chamber (including its casing) is studied here in the context of its azimuthal thermo-acoustic response. To do so, a fully compressible, multi-species reacting LES is used on two meshes yielding two fully unsteady turbulent reacting predictions of the same configuration. The two tetrahedra meshes contain respectively 38 and 93 millions cells. Limit-cycles as obtained by the two LES are gauged against each other for various flow quantities such as mean velocity profiles, flame position and temperature fields. The thermo-acoustic limit-cycles are observed to be relatively indepedent of the grid resolution which comforts the use of LES tools to provide insights and understanding of the mechanisms triggering the coupling between the system acoustic eigenmodes and combustion.

Assessment of adhesion formation to intra-abdominal polypropylene mesh and polytetrafluoroethylene mesh.

PubMed

Matthews, Brent D; Pratt, Broc L; Pollinger, Harrison S; Backus, Charles L; Kercher, Kent W; Sing, R F; Heniford, B Todd

2003-10-01

The development of intra-abdominal adhesions, bowel obstruction, and enterocutaneous fistulas are potentially severe complications related to the intraperitoneal placement of prosthetic biomaterials. The purpose of this study was to determine the natural history of adhesion formation to polypropylene mesh and two types of polytetrafluoroethylene (ePTFE) mesh when placed intraperitoneally in a rabbit model that simulates laparoscopic ventral hernia repair. Thirty New Zealand white rabbits were used for this study. A 10-cm midline incision was performed for intra-abdominal access and a 2 cm x 2 cm piece of mesh (n = 60) was sewn to an intact peritoneum on each side of the midline. Two types of ePTFE mesh (Dual Mesh and modified Dual Mesh, W.L. Gore & Assoc., Flagstaff, AZ) and polypropylene mesh were compared. The rate of adhesion formation was evaluated by direct visualization using microlaparoscopy (2-mm endoscope/trocar) at 7 days, 3 weeks, 9 weeks, and 16 weeks after mesh implantation. Adhesions to the prosthetic mesh were scored for extent (%) using the Modified Diamond Scale (0 = 0%, 1 50%). At necropsy the mesh was excised en bloc with the anterior abdominal wall for histological evaluation of mesothelial layer growth. The mean adhesion score for the polypropylene mesh was significantly greater (P < 0.05) than Dual Mesh at 9 weeks and 16 weeks and modified Dual Mesh at 7 days, 9 weeks, and 16 weeks. Fifty-five percent (n = 11) of the polypropylene mesh had adhesions to small intestine or omentum at necropsy compared to 30% (n = 6) of the Dual Mesh and 20% (n = 4) of the modified Dual Mesh. There was a significantly greater percentage (P < 0.003) of ePTFE mesh mesothelialized at explant (modified Dual Mesh 44.2%; Dual Mesh 55.8%) compared to the polypropylene mesh (12.9%). Serial microlaparoscopic evaluation of intraperitoneally implanted polypropylene mesh and ePTFE mesh in a rabbit model revealed a progression of adhesions to polypropylene mesh over a 16 week period. The pore size of mesh is critical in the development and maintenance of abdominal adhesions and tissue ingrowth. The macroporous polypropylene mesh promoted adhesion formation, while the microporous nature of the visceral side of the ePTFE served as a barrier to adhesions.

Which drugs are risk factors for the development of gastroesophageal reflux disease?

PubMed

Mungan, Zeynel; Pınarbaşı Şimşek, Binnur

2017-12-01

Gastroesophageal reflux disease (GERD), which is common in many communities, is associated with structural factors, eating habits, and the use of certain drugs. The use of such drugs can lead to the emergence of GERD and can also exacerbate existing reflux symptoms. These drugs can contribute to GERD by directly causing mucosal damage, by reducing lower esophageal sphincter pressure (LESP), or by affecting esophagogastric motility. In this article, we report our investigation of the relationships between GERD and medications within the scope of the "Turkish GERD Consensus Group." For the medication groups for which sufficient data were obtained (Figure 1), a systematic literature review in English was conducted using the keywords "gastroesophageal reflux" [MeSH Terms] and "anti-inflammatory agents, non-steroidal" [MeSH Terms], "gastroesophageal reflux" [MeSH Terms] and "acetylsalicylic acid" [MeSH Terms], "gastroesophageal reflux" [All Fields] and "estrogenic agents" [All Fields], "gastroesophageal reflux" [All Fields] and "progesterones" [All Fields], "gastroesophageal reflux" [All Fields] and "hormone replacement therapy" [All Fields], "gastroesophageal reflux" [MeSH Terms] and "diphosphonates" [MeSH Terms] OR "diphosphonates" [All Fields], "calcium channel blockers" [MeSH Terms] and "gastroesophageal reflux" [MeSH Terms], "gastroesophageal reflux" [MeSH Terms] and "nitrates" [MeSH Terms], "gastroesophageal reflux" [MeSH Terms] and "antidepressive agents" [MeSH Terms], "gastroesophageal reflux" [MeSH Terms] and "benzodiazepines" [MeSH Terms] and "hypnotic drugs" [MeSH Terms], "gastroesophageal reflux" [MeSH Terms] and "cholinergic antagonists" [MeSH Terms], "gastroesophageal reflux" [MeSH Terms] and "theophylline" [MeSH Terms], and "gastroesophageal reflux [MeSH Terms] AND "anti-asthmatic agents" [MeSH Terms]. The studies were analyzed and the results are presented here.

New Position Algorithms for the 3-D CZT Drift Detector

NASA Astrophysics Data System (ADS)

Budtz-Jørgensen, C.; Kuvvetli, I.

2017-06-01

The 3-D position sensitive CZT detector for high-energy astrophysics developed at DTU has been investigated with a digitizer readout system. The 3-D CZT detector is based on the CZT drift-strip detector principle and was fabricated using a REDLEN CZT crystal (20 mm × 20 mm × 5 mm). The detector contains 12 drift cells, each comprising one collecting anode strip with four drift strips, biased such that the electrons are focused and collected by the anode strips. Three-dimensional position determination is achieved using the anode strip signals, the drift-strip signals, and the signals from ten cathode strips. For the characterization work, we used a DAQ system with a 16 channels 250-MHz 14-b digitizer, SIS3316. It allowed us to analyze the pulse shapes of the signals from four detector cells at a time. The 3-D CZT setup was characterized with a finely collimated radioactive source of 137Cs at 662 keV. The analysis required development of novel position determination algorithms which are the subject of this paper. Using the digitizer readout, we demonstrate improved position determination compared to the previous read out system based on analog electronics. Position resolutions of 0.4-mm full width at half maximum (FWHM) in the x-, y-, and z-directions were achieved and the energy resolution was 7.2-keV FWHM at 662 keV. The timing information allows identification of multiple interaction events within one detector cell, e.g., Compton scattering followed by photoelectric absorption. These characteristics are very important for a high-energy spectral-imager suitable for use in advanced Compton telescopes, or as focal detector for new hard X-ray and soft γ-ray focusing telescopes or in polarimeter instrumentation. CZT detectors are attractive for these applications since they offer relatively high-quantum efficiency. From a technical point of view it is advantageous that their cooling requirements are modest.

Three point lead screw positioning apparatus for a cavity tuning plate

NASA Technical Reports Server (NTRS)

Calco, Frank S. (Inventor)

1993-01-01

Three lead screws are provided for adjusting the position of a traversing plate. Each of the three lead screws is threaded through a collar that is press fitted through the center of one of three pinion gears. A sun gear meshes with all three pinion gears and transversely moves the three lead screws upon actuation of a drive gear. The drive gear meshes with the sun gear and is driven by a handle or servomotor. When the handle or servomotor rotates the drive gear, the sun gear rotates causing the three pinion gears to rotate, thus, causing transverse movement of the three lead screws and, accordingly, transverse movement of the transversing plate. When the drive gear rotates, the traversing plate is driven in and out of a microwave cavity. Thus, the length or size of the cavity can be tuned while maintaining the traversing plate in an exact parallel relationship with an opposing plate on another end of the cavity.

Three point lead screw positioning apparatus for a cavity tuning plate

NASA Astrophysics Data System (ADS)

Calco, Frank S.

1993-09-01

Three lead screws are provided for adjusting the position of a traversing plate. Each of the three lead screws is threaded through a collar that is press fitted through the center of one of three pinion gears. A sun gear meshes with all three pinion gears and transversely moves the three lead screws upon actuation of a drive gear. The drive gear meshes with the sun gear and is driven by a handle or servomotor. When the handle or servomotor rotates the drive gear, the sun gear rotates causing the three pinion gears to rotate, thus, causing transverse movement of the three lead screws and, accordingly, transverse movement of the transversing plate. When the drive gear rotates, the traversing plate is driven in and out of a microwave cavity. Thus, the length or size of the cavity can be tuned while maintaining the traversing plate in an exact parallel relationship with an opposing plate on another end of the cavity.

Preparations for the Advanced Scintillator Compton Telescope (ASCOT) balloon flight

NASA Astrophysics Data System (ADS)

Sharma, T.; Bloser, P. F.; Legere, J. S.; Bancroft, C. M.; McConnell, M. L.; Ryan, J. M.; Wright, A. M.

2017-08-01

We describe our ongoing work to develop a new medium-energy gamma-ray Compton telescope using advanced scintillator materials combined with silicon photomultiplier readouts and fly it on a scientific balloon. There is a need in high-energy astronomy for a medium-energy gamma-ray mission covering the energy range from approximately 0.4 - 20 MeV to follow the success of the COMPTEL instrument on CGRO. We believe that directly building on the legacy of COMPTEL, using relatively robust, low-cost, off-the-shelf technologies, is the most promising path for such a mission. Fortunately, high-performance scintillators, such as Cerium Bromide (CeBr3) and p-terphenyl, and compact readout devices, such as silicon photomultipliers (SiPMs), are already commercially available and capable of meeting this need. We are now constructing an Advanced Scintillator Compton Telescope (ASCOT) with SiPM readout, with the goal of imaging the Crab Nebula at MeV energies from a high-altitude balloon flight. We expect a 4-sigma detection at 1 MeV in a single transit. We present calibration results of the detector modules, and updated simulations of the balloon instrument sensitivity. If successful, this project will demonstrate that the energy, timing, and position resolution of this technology are sufficient to achieve an order of magnitude improvement in sensitivity in the medium-energy gamma-ray band, were it to be applied to a 1 cubic meter instrument on a long-duration balloon or Explorer platform.

A feasibility study of a data acquisition system for a silicon strip detector with a digital readout scheme

NASA Astrophysics Data System (ADS)

Ikeda, Hirokazu; Ikeda, Mitsuo; Inaba, Susumu; Tanaka, Manobu

1993-06-01

We describe a prototype data acquisition system for a silicon strip detector, which has been developed in terms of a digital readout scheme. The system consists of a master timing generator, readout controller, and a detector emulator card on which we use custom VLSI shift registers with operating clock frequency of 30 MHz.

Optical Neural Interfaces

PubMed Central

Warden, Melissa R.; Cardin, Jessica A.; Deisseroth, Karl

2014-01-01

Genetically encoded optical actuators and indicators have changed the landscape of neuroscience, enabling targetable control and readout of specific components of intact neural circuits in behaving animals. Here, we review the development of optical neural interfaces, focusing on hardware designed for optical control of neural activity, integrated optical control and electrical readout, and optical readout of population and single-cell neural activity in freely moving mammals. PMID:25014785

Frequency division multiplexed readout of TES detectors with baseband feedback

NASA Astrophysics Data System (ADS)

den Hartog, R.; Audley, M. D.; Beyer, J.; Bruijn, M. P.; de Korte, P.; Gottardi, L.; Hijmering, R.; Jackson, B.; Nieuwenhuizen, A.; van der Kuur, J.; van Leeuwen, B.-J.; Van Loon, D.

2012-09-01

SRON is developing an electronic system for the multiplexed read-out of an array of transition edge sensors (TES) by combining the techniques of frequency domain multiplexing (FDM) with base-band feedback (BBFB). The astronomical applications are the read-out of soft X-ray microcalorimeters and the far-infrared bolometers for the SAFARI instrument on the Japanese mission SPICA. In this paper we derive the requirements for the read-out system regarding noise and dynamic range in the context of the SAFARI instrument, and demonstrate that the current experimental prototype is capable of simultaneously locking 57 channels and complies with these requirements.

X-ray imaging using amorphous selenium: a photoinduced discharge readout method for digital mammography.

PubMed

Rowlands, J A; Hunter, D M; Araj, N

1991-01-01

A new digital image readout method for electrostatic charge images on photoconductive plates is described. The method can be used to read out images on selenium plates similar to those used in xeromammography. The readout method, called the air-gap photoinduced discharge method (PID), discharges the latent image pixel by pixel and measures the charge. The PID readout method, like electrometer methods, is linear. However, the PID method permits much better resolution than scanning electrometers while maintaining quantum limited performance at high radiation exposure levels. Thus the air-gap PID method appears to be uniquely superior for high-resolution digital imaging tasks such as mammography.

General method for extracting the quantum efficiency of dispersive qubit readout in circuit QED

NASA Astrophysics Data System (ADS)

Bultink, C. C.; Tarasinski, B.; Haandbæk, N.; Poletto, S.; Haider, N.; Michalak, D. J.; Bruno, A.; DiCarlo, L.

2018-02-01

We present and demonstrate a general three-step method for extracting the quantum efficiency of dispersive qubit readout in circuit QED. We use active depletion of post-measurement photons and optimal integration weight functions on two quadratures to maximize the signal-to-noise ratio of the non-steady-state homodyne measurement. We derive analytically and demonstrate experimentally that the method robustly extracts the quantum efficiency for arbitrary readout conditions in the linear regime. We use the proven method to optimally bias a Josephson traveling-wave parametric amplifier and to quantify different noise contributions in the readout amplification chain.

Design of a Multi-Channel Low-Noise Readout ASIC for CdZnTe-Based X-Ray and γ-Ray Spectrum Analyzer

NASA Astrophysics Data System (ADS)

Gan, B.; Wei, T.; Gao, W.; Zheng, R.; Hu, Y.

2015-10-01

In this paper, we report on the recent development of a 32-channel low-noise front-end readout ASIC for cadmium zinc telluride (CdZnTe) X-ray and γ-ray detectors. Each readout channel includes a charge sensitive amplifier, a CR-RC shaping amplifier and an analog output buffer. The readout ASIC is implemented using TSMC 0.35 - μm mixed-signal CMOS technology, the die size of the prototype chip is 2.2 mm ×4.8 mm. At room temperature, the equivalent noise level of a typical channel reaches 133 e- (rms) with the input parasitic capacitance of 0 pF for the average power consumption of 2.8 mW per channel. The linearity error is less than ±2% and the input energy dynamic range of the readout ASIC is from 10 keV to 1 MeV. The crosstalk between the channels is less than 0.4%. By connecting the readout ASIC to a CdZnTe detector, we obtained a γ-ray spectrum, the energy resolution is 1.8% at the 662-keV line of 137Cs source.

An energy-efficient readout circuit for resonant sensors based on ring-down measurement

NASA Astrophysics Data System (ADS)

Zeng, Z.; Pertijs, M. A. P.; Karabacak, D. M.

2013-02-01

This paper presents an energy-efficient readout circuit for resonant sensors that operates based on a transient measurement method. The resonant sensor is driven at a frequency close to its resonance frequency by an excitation source that can be intermittently disconnected, causing the sensor to oscillate at its resonance frequency with exponentially decaying amplitude. By counting the zero crossings of this ring-down response, the interface circuit can detect the resonance frequency. In contrast with oscillator-based readout, the presented readout circuit is readily able to detect quality factor (Q) of the resonator from the envelope of the ring-down response, and can be used even in the presence of large parasitic capacitors. A prototype of the readout circuit has been integrated in 0.35 μm CMOS technology, and consumes only 36 μA from a 3.3 V supply during a measurement time of 2 ms. The resonance frequency and quality factor of a micro-machined SiN resonator obtained using this prototype are in good agreement with results obtained using impedance analysis. Furthermore, a clear transient response is observed to ethanol flow using the presented readout, demonstrating the use of this technique in sensing applications.

Combined in vivo and ex vivo analysis of mesh mechanics in a porcine hernia model.

PubMed

Kahan, Lindsey G; Lake, Spencer P; McAllister, Jared M; Tan, Wen Hui; Yu, Jennifer; Thompson, Dominic; Brunt, L Michael; Blatnik, Jeffrey A

2018-02-01

Hernia meshes exhibit variability in mechanical properties, and their mechanical match to tissue has not been comprehensively studied. We used an innovative imaging model of in vivo strain tracking and ex vivo mechanical analysis to assess effects of mesh properties on repaired abdominal walls in a porcine model. We hypothesized that meshes with dissimilar mechanical properties compared to native tissue would alter abdominal wall mechanics more than better-matched meshes. Seven mini-pigs underwent ventral hernia creation and subsequent open repair with one of two heavyweight polypropylene meshes. Following mesh implantation with attached radio-opaque beads, fluoroscopic images were taken at insufflation pressures from 5 to 30 mmHg on postoperative days 0, 7, and 28. At 28 days, animals were euthanized and ex vivo mechanical testing performed on full-thickness samples across repaired abdominal walls. Testing was conducted on 13 mini-pig controls, and on meshes separately. Stiffness and anisotropy (the ratio of stiffness in the transverse versus craniocaudal directions) were assessed. 3D reconstructions of repaired abdominal walls showed stretch patterns. As pressure increased, both meshes expanded, with no differences between groups. Over time, meshes contracted 17.65% (Mesh A) and 0.12% (Mesh B; p = 0.06). Mesh mechanics showed that Mesh A deviated from anisotropic native tissue more than Mesh B. Compared to native tissue, Mesh A was stiffer both transversely and craniocaudally. Explanted repaired abdominal walls of both treatment groups were stiffer than native tissue. Repaired tissue became less anisotropic over time, as mesh properties prevailed over native abdominal wall properties. This technique assessed 3D stretch at the mesh level in vivo in a porcine model. While the abdominal wall expanded, mesh-ingrown areas contracted, potentially indicating stresses at mesh edges. Ex vivo mechanics demonstrate that repaired tissue adopts mesh properties, suggesting that a better-matched mesh could reduce changes to abdominal wall mechanics.

Mesh fixation in laparoscopic incisional hernia repair: glue fixation provides attachment strength similar to absorbable tacks but differs substantially in different meshes.

PubMed

Rieder, Erwin; Stoiber, Martin; Scheikl, Verena; Poglitsch, Marcus; Dal Borgo, Andrea; Prager, Gerhard; Schima, Heinrich

2011-01-01

Laparoscopic ventral hernia repair has gained popularity among minimally invasive surgeons. However, mesh fixation remains a matter of discussion. This study was designed to compare noninvasive fibrin-glue attachment with tack fixation of meshes developed primarily for intra-abdominal use. It was hypothesized that particular mesh structures would substantially influence detachment force. For initial evaluation, specimens of laminated polypropylene/polydioxanone meshes were anchored to porcine abdominal walls by either helical titanium tacks or absorbable tacks in vitro. A universal tensile-testing machine was used to measure tangential detachment forces (TF). For subsequent experiments of glue fixation, polypropylene/polydioxanone mesh and 4 additional meshes with diverse particular mesh structure, ie, polyvinylidene fluoride/polypropylene mesh, a titanium-coated polypropylene mesh, a polyester mesh bonded with a resorbable collagen, and a macroporous condensed PTFE mesh were evaluated. TF tests revealed that fibrin-glue attachment was not substantially different from that achieved with absorbable tacks (median TF 7.8 Newton [N], range 1.3 to 15.8 N), but only when certain open porous meshes (polyvinylidene fluoride/polypropylene mesh: median 6.2 N, range 3.4 to 10.3 N; titanium-coated polypropylene mesh: median 5.2 N, range 2.1 to 11.7 N) were used. Meshes coated by an anti-adhesive barrier (polypropylene/polydioxanone mesh: median 3.1 N, range 1.7 to 5.8 N; polyester mesh bonded with a resorbable collagen: median 1.3 N, range 0.5 to 1.9 N), or the condensed PTFE mesh (median 3.1 N, range 2.1 to 7.0 N) provided a significantly lower TF (p < 0.01). Fibrin glue appears to be an appealing noninvasive option for mesh fixation in laparoscopic ventral hernia repair, but only if appropriate meshes are used. Glue can also serve as an adjunct to mechanical fixation to reduce the number of invasive tacks. Copyright © 2010 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

The PANDA Endcap Disc DIRC

NASA Astrophysics Data System (ADS)

Föhl, K.; Ali, A.; Belias, A.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Kalicy, G.; Krebs, M.; Lehmann, D.; Nerling, F.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Böhm, M.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Düren, M.; Etzelmüller, E.; Hayrapetyan, A.; Kreutzfeld, K.; Merle, O.; Rieke, J.; Schmidt, M.; Wasem, T.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Schlimme, S.; Sfienti, C.; Thiel, M.

2018-02-01

Positively identifying charged kaons in the PANDA forward endcap solid angle range can be achieved with the Endcap Disc DIRC, allowing kaon-pion separation from 1 up to 4 GeV/c with a separation power of at least 3 standard deviations. Design, performance, and components of this DIRC are given, including the recently introduced TOFPET-ASIC based read-out. Results of a prototype operated in a test beam at DESY in 2016 are shown.

Longitudinal Assessment of Disease Sites by Attachment Level Changes and Bone Density Loss by Digital Image Analysis

DTIC Science & Technology

1989-04-01

subtraction readout (Klein 1967). This technique was used to investigate the early formation of periapical lesions prior to diagnosis by clinical...have investigated the diagnostic sensitivity of radiographs by determining the size, shape and position of bony lesions that can be visualized in...radiographs. Several studies using created defects in dried skulls have reported that interproximal lesions were not visible as long as the cortical plates

Implementation and assessment of diffusion-weighted partial Fourier readout-segmented echo-planar imaging.

PubMed

Frost, Robert; Porter, David A; Miller, Karla L; Jezzard, Peter

2012-08-01

Single-shot echo-planar imaging has been used widely in diffusion magnetic resonance imaging due to the difficulties in correcting motion-induced phase corruption in multishot data. Readout-segmented EPI has addressed the multishot problem by introducing a two-dimensional nonlinear navigator correction with online reacquisition of uncorrectable data to enable acquisition of high-resolution diffusion data with reduced susceptibility artifact and T*(2) blurring. The primary shortcoming of readout-segmented EPI in its current form is its long acquisition time (longer than similar resolution single-shot echo-planar imaging protocols by approximately the number of readout segments), which limits the number of diffusion directions. By omitting readout segments at one side of k-space and using partial Fourier reconstruction, readout-segmented EPI imaging times could be reduced. In this study, the effects of homodyne and projection onto convex sets reconstructions on estimates of the fractional anisotropy, mean diffusivity, and diffusion orientation in fiber tracts and raw T(2)- and trace-weighted signal are compared, along with signal-to-noise ratio results. It is found that projections onto convex sets reconstruction with 3/5 segments in a 2 mm isotropic diffusion tensor image acquisition and 9/13 segments in a 0.9 × 0.9 × 4.0 mm(3) diffusion-weighted image acquisition provide good fidelity relative to the full k-space parameters. This allows application of readout-segmented EPI to tractography studies, and clinical stroke and oncology protocols. Copyright © 2011 Wiley-Liss, Inc.

[Laparoscopic promontofixation technique].

PubMed

Mugnier, C; Gaston, R; Hoepffner, J L; Piéchaud, T

2005-11-01

Laparoscopic promontofixation often remains possible whatever the previous history of pelvic surgery, including the placing of prosthetic material. Preoperative care is standardized and is accompanied by antibiotic prophylaxis, preventive antithrombotic treatment and in the event of a history of pelvic surgery, a digestive preparation. Positioning of the patient must plan a 30 degrees Trendelenbourg position. After the introduction of trocars, initial surgery comprises interrectovaginal dissection to free the whole posterior surface of the vagina. This is followed by the installation of a posterior mesh pre-cut in an arch. The anterior face of the promontory is then freed after incision of the posterior peritoneum with the patient placed beforehand in a Trendelenbourg position. After intervesical vaginal dissection, the anterior prosthesis comprising a precut polyester mesh is fixed avoiding excess traction. The end of the surgery involves careful reperitonization of all the prosthetic parts. Possible specific surgical complications are vascular and visceral wounds. Postoperative secondary haemorrhage and gastrointestinal occlusion may occur. Occurrence of an inflammatory syndrome and low back pain suggests spondylodicitis and MRI should be performed. Vaginal erosion on the prosthesis (1.6 to 10% depending on the series) may occur after several months and seems relatively independent of the prosthetic material used.

Method and system for mesh network embedded devices

NASA Technical Reports Server (NTRS)

Wang, Ray (Inventor)

2009-01-01

A method and system for managing mesh network devices. A mesh network device with integrated features creates an N-way mesh network with a full mesh network topology or a partial mesh network topology.

Experimental demonstration of the optical multi-mesh hypercube: scaleable interconnection network for multiprocessors and multicomputers.

PubMed

Louri, A; Furlonge, S; Neocleous, C

1996-12-10

A prototype of a novel topology for scaleable optical interconnection networks called the optical multi-mesh hypercube (OMMH) is experimentally demonstrated to as high as a 150-Mbit/s data rate (2(7) - 1 nonreturn-to-zero pseudo-random data pattern) at a bit error rate of 10(-13)/link by the use of commercially available devices. OMMH is a scaleable network [Appl. Opt. 33, 7558 (1994); J. Lightwave Technol. 12, 704 (1994)] architecture that combines the positive features of the hypercube (small diameter, connectivity, symmetry, simple routing, and fault tolerance) and the mesh (constant node degree and size scaleability). The optical implementation method is divided into two levels: high-density local connections for the hypercube modules, and high-bit-rate, low-density, long connections for the mesh links connecting the hypercube modules. Free-space imaging systems utilizing vertical-cavity surface-emitting laser (VCSEL) arrays, lenslet arrays, space-invariant holographic techniques, and photodiode arrays are demonstrated for the local connections. Optobus fiber interconnects from Motorola are used for the long-distance connections. The OMMH was optimized to operate at the data rate of Motorola's Optobus (10-bit-wide, VCSEL-based bidirectional data interconnects at 150 Mbits/s). Difficulties encountered included the varying fan-out efficiencies of the different orders of the hologram, misalignment sensitivity of the free-space links, low power (1 mW) of the individual VCSEL's, and noise.

Carotenoids as Potential Antioxidant Agents in Stroke Prevention: A Systematic Review

PubMed Central

Bahonar, Ahmad; Saadatnia, Mohammad; Khorvash, Fariborz; Maracy, Mohammadreza; Khosravi, Alireza

2017-01-01

Stroke and other cerebrovascular diseases are among the most common causes of death worldwide. Prevention of modifiable risk factors is a cost-effective approach to decrease the risk of stroke. Oxidative stress is regarded as the major flexible operative agent in ischemic brain damage. This review presents recent scientific advances in understanding the role of carotenoids as antioxidants in lowering stroke risk based on observational studies. We searched Medline using the following terms: (Carotenoids [MeSH] OR Carotenes [tiab] OR Carotene [tiab] OR “lycopene [Supplementary Concept]” [MeSH] OR lycopene [tiab] OR beta-Carotene [tiab]) AND (stroke [MeSH] OR stroke [tiab] OR “Cerebrovascular Accident” [tiab] OR “Cerebrovascular Apoplexy” [tiab] OR “Brain Vascular Accident” [tiab] OR “Cerebrovascular Stroke” [tiab]) AND (“oxidative stress” [MeSH] OR “oxidative stress”[tiab]). This search considered papers that had been published between 2000 and 2017. Recent studies indicated that high dietary intake of six main carotenoids (i.e., lycopene, <- and®-carotene, lutein, zeaxanthin, and astaxanthin) was associated with reduced risk of stroke and other cardiovascular outcomes. However, the main mechanism of the action of these nutrients was not identified, and multiple mechanisms except antioxidant activity were suggested to be involved in the observed beneficial effects. The dietary intake of six major carotenoids should be promoted as this may have a substantial positive effect on stroke prevention and stroke mortality reduction. PMID:28983399

Convergence study of global meshing on enamel-cement-bracket finite element model

NASA Astrophysics Data System (ADS)

Samshuri, S. F.; Daud, R.; Rojan, M. A.; Basaruddin, K. S.; Abdullah, A. B.; Ariffin, A. K.

2017-09-01

This paper presents on meshing convergence analysis of finite element (FE) model to simulate enamel-cement-bracket fracture. Three different materials used in this study involving interface fracture are concerned. Complex behavior ofinterface fracture due to stress concentration is the reason to have a well-constructed meshing strategy. In FE analysis, meshing size is a critical factor that influenced the accuracy and computational time of analysis. The convergence study meshing scheme involving critical area (CA) and non-critical area (NCA) to ensure an optimum meshing sizes are acquired for this FE model. For NCA meshing, the area of interest are at the back of enamel, bracket ligature groove and bracket wing. For CA meshing, area of interest are enamel area close to cement layer, the cement layer and bracket base. The value of constant NCA meshing tested are meshing size 1 and 0.4. The value constant CA meshing tested are 0.4 and 0.1. Manipulative variables are randomly selected and must abide the rule of NCA must be higher than CA. This study employed first principle stresses due to brittle failure nature of the materials used. Best meshing size are selected according to convergence error analysis. Results show that, constant CA are more stable compare to constant NCA meshing. Then, 0.05 constant CA meshing are tested to test the accuracy of smaller meshing. However, unpromising result obtained as the errors are increasing. Thus, constant CA 0.1 with NCA mesh of 0.15 until 0.3 are the most stable meshing as the error in this region are lowest. Convergence test was conducted on three selected coarse, medium and fine meshes at the range of NCA mesh of 0.15 until 3 and CA mesh area stay constant at 0.1. The result shows that, at coarse mesh 0.3, the error are 0.0003% compare to 3% acceptable error. Hence, the global meshing are converge as the meshing size at CA 0.1 and NCA 0.15 for this model.

Method and apparatus for connecting finite element meshes and performing simulations therewith

DOEpatents

Dohrmann, Clark R.; Key, Samuel W.; Heinstein, Martin W.

2003-05-06

The present invention provides a method of connecting dissimilar finite element meshes. A first mesh, designated the master mesh, and a second mesh, designated the slave mesh, each have interface surfaces proximal the other. Each interface surface has a corresponding interface mesh comprising a plurality of interface nodes. Each slave interface node is assigned new coordinates locating the interface node on the interface surface of the master mesh. The slave interface surface is further redefined to be the projection of the slave interface mesh onto the master interface surface.

Deploy production sliding mesh capability with linear solver benchmarking.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Domino, Stefan P.; Thomas, Stephen; Barone, Matthew F.

Wind applications require the ability to simulate rotating blades. To support this use-case, a novel design-order sliding mesh algorithm has been developed and deployed. The hybrid method combines the control volume finite element methodology (CVFEM) with concepts found within a discontinuous Galerkin (DG) finite element method (FEM) to manage a sliding mesh. The method has been demonstrated to be design-order for the tested polynomial basis (P=1 and P=2) and has been deployed to provide production simulation capability for a Vestas V27 (225 kW) wind turbine. Other stationary and canonical rotating ow simulations are also presented. As the majority of wind-energymore » applications are driving extensive usage of hybrid meshes, a foundational study that outlines near-wall numerical behavior for a variety of element topologies is presented. Results indicate that the proposed nonlinear stabilization operator (NSO) is an effective stabilization methodology to control Gibbs phenomena at large cell Peclet numbers. The study also provides practical mesh resolution guidelines for future analysis efforts. Application-driven performance and algorithmic improvements have been carried out to increase robustness of the scheme on hybrid production wind energy meshes. Specifically, the Kokkos-based Nalu Kernel construct outlined in the FY17/Q4 ExaWind milestone has been transitioned to the hybrid mesh regime. This code base is exercised within a full V27 production run. Simulation timings for parallel search and custom ghosting are presented. As the low-Mach application space requires implicit matrix solves, the cost of matrix reinitialization has been evaluated on a variety of production meshes. Results indicate that at low element counts, i.e., fewer than 100 million elements, matrix graph initialization and preconditioner setup times are small. However, as mesh sizes increase, e.g., 500 million elements, simulation time associated with \\setup-up" costs can increase to nearly 50% of overall simulation time when using the full Tpetra solver stack and nearly 35% when using a mixed Tpetra- Hypre-based solver stack. The report also highlights the project achievement of surpassing the 1 billion element mesh scale for a production V27 hybrid mesh. A detailed timing breakdown is presented that again suggests work to be done in the setup events associated with the linear system. In order to mitigate these initialization costs, several application paths have been explored, all of which are designed to reduce the frequency of matrix reinitialization. Methods such as removing Jacobian entries on the dynamic matrix columns (in concert with increased inner equation iterations), and lagging of Jacobian entries have reduced setup times at the cost of numerical stability. Artificially increasing, or bloating, the matrix stencil to ensure that full Jacobians are included is developed with results suggesting that this methodology is useful in decreasing reinitialization events without loss of matrix contributions. With the above foundational advances in computational capability, the project is well positioned to begin scientific inquiry on a variety of wind-farm physics such as turbine/turbine wake interactions.« less

A methodology for quadrilateral finite element mesh coarsening

DOE PAGES

Staten, Matthew L.; Benzley, Steven; Scott, Michael

2008-03-27

High fidelity finite element modeling of continuum mechanics problems often requires using all quadrilateral or all hexahedral meshes. The efficiency of such models is often dependent upon the ability to adapt a mesh to the physics of the phenomena. Adapting a mesh requires the ability to both refine and/or coarsen the mesh. The algorithms available to refine and coarsen triangular and tetrahedral meshes are very robust and efficient. However, the ability to locally and conformally refine or coarsen all quadrilateral and all hexahedral meshes presents many difficulties. Some research has been done on localized conformal refinement of quadrilateral and hexahedralmore » meshes. However, little work has been done on localized conformal coarsening of quadrilateral and hexahedral meshes. A general method which provides both localized conformal coarsening and refinement for quadrilateral meshes is presented in this paper. This method is based on restructuring the mesh with simplex manipulations to the dual of the mesh. Finally, this method appears to be extensible to hexahedral meshes in three dimensions.« less

Adaptive Skin Meshes Coarsening for Biomolecular Simulation

PubMed Central

Shi, Xinwei; Koehl, Patrice

2011-01-01

In this paper, we present efficient algorithms for generating hierarchical molecular skin meshes with decreasing size and guaranteed quality. Our algorithms generate a sequence of coarse meshes for both the surfaces and the bounded volumes. Each coarser surface mesh is adaptive to the surface curvature and maintains the topology of the skin surface with guaranteed mesh quality. The corresponding tetrahedral mesh is conforming to the interface surface mesh and contains high quality tetrahedral that decompose both the interior of the molecule and the surrounding region (enclosed in a sphere). Our hierarchical tetrahedral meshes have a number of advantages that will facilitate fast and accurate multigrid PDE solvers. Firstly, the quality of both the surface triangulations and tetrahedral meshes is guaranteed. Secondly, the interface in the tetrahedral mesh is an accurate approximation of the molecular boundary. In particular, all the boundary points lie on the skin surface. Thirdly, our meshes are Delaunay meshes. Finally, the meshes are adaptive to the geometry. PMID:21779137

The Background-Limited Infrared Submillimeter Spectrograph (BLISS) for SPICA

NASA Astrophysics Data System (ADS)

Bradford, Charles; BLISS-SPICA Study Team

2011-05-01

The far-IR waveband carries half of the photon energy ever produced in galaxies and quasars, evidence of the major role of dust-obscured star formation and black-hole growth had in bringing about the modern Universe. The bulk of this dust-obscured activity appears to have occurred in the first half of the Universe's history (z>1). We are developing the Background-Limited Infrared-Submillimeter Spectrograph (BLISS) to capitalize on SPICA's cold telescope and provide a breakthrough far-IR spectroscopy capability. BLISS-SPICA is 6 orders of magnitude faster than the spectrometers on Herschel and SOFIA in obtaining full-band spectra, and offer the capability to overcome the spatial confusion limit with spectroscopic capability. BLISS-SPICA will observe dust-obscured galaxies at all epochs back to the first billion years after the Big Bang (redshift 6), thereby probing the complete history of dust-obscured star formation and black-hole growth. It will also be extremely powerful for studying ice-giant planet formation in protoplanetary disks, with its sensitivity to very small amounts of gas. Given its enormous potential, BLISS has been recommended by Astro2010 as an example US contribution to SPICA. BLISS covers the 38-433 micron range in six grating-spectrometer bands, with two simultaneous sky positions. The baseline detector package is 4224 silicon-nitride micro-mesh leg-isolated bolometers with superconducting transition-edge-sensed (TES) thermistors, read out with a cryogenic time-domain multiplexer. All spectrometers and detector arrays are cooled to 50mK for optimal sensitivity. All technical elements of BLISS have heritage in mature scientific instruments, and many have flown. We present the science case for BLISS, as well as our progress in the key technical aspects: 1) detector and readout performance demonstration, 2) opto-mechanical instrument configuration, and 3) sub-K cooling and cryogenic system approach.

Radiation imaging with optically read out GEM-based detectors

NASA Astrophysics Data System (ADS)

Brunbauer, F. M.; Lupberger, M.; Oliveri, E.; Resnati, F.; Ropelewski, L.; Streli, C.; Thuiner, P.; van Stenis, M.

2018-02-01

Modern imaging sensors allow for high granularity optical readout of radiation detectors such as MicroPattern Gaseous Detectors (MPGDs). Taking advantage of the high signal amplification factors achievable by MPGD technologies such as Gaseous Electron Multipliers (GEMs), highly sensitive detectors can be realised and employing gas mixtures with strong scintillation yield in the visible wavelength regime, optical readout of such detectors can provide high-resolution event representations. Applications from X-ray imaging to fluoroscopy and tomography profit from the good spatial resolution of optical readout and the possibility to obtain images without the need for extensive reconstruction. Sensitivity to low-energy X-rays and energy resolution permit energy resolved imaging and material distinction in X-ray fluorescence measurements. Additionally, the low material budget of gaseous detectors and the possibility to couple scintillation light to imaging sensors via fibres or mirrors makes optically read out GEMs an ideal candidate for beam monitoring detectors in high energy physics as well as radiotherapy. We present applications and achievements of optically read out GEM-based detectors including high spatial resolution imaging and X-ray fluorescence measurements as an alternative readout approach for MPGDs. A detector concept for low intensity applications such as X-ray crystallography, which maximises detection efficiency with a thick conversion region but mitigates parallax-induced broadening is presented and beam monitoring capabilities of optical readout are explored. Augmenting high resolution 2D projections of particle tracks obtained with optical readout with timing information from fast photon detectors or transparent anodes for charge readout, 3D reconstruction of particle trajectories can be performed and permits the realisation of optically read out time projection chambers. Combining readily available high performance imaging sensors with compatible scintillating gases and the strong signal amplification factors achieved by MPGDs makes optical readout an attractive alternative to the common concept of electronic readout of radiation detectors. Outstanding signal-to-noise ratios and robustness against electronic noise allow unprecedented imaging capabilities for various applications in fields ranging from high energy physics to medical instrumentation.

User Manual for the PROTEUS Mesh Tools

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Micheal A.; Shemon, Emily R.

2015-06-01

This report describes the various mesh tools that are provided with the PROTEUS code giving both descriptions of the input and output. In many cases the examples are provided with a regression test of the mesh tools. The most important mesh tools for any user to consider using are the MT_MeshToMesh.x and the MT_RadialLattice.x codes. The former allows the conversion between most mesh types handled by PROTEUS while the second allows the merging of multiple (assembly) meshes into a radial structured grid. Note that the mesh generation process is recursive in nature and that each input specific for a givenmore » mesh tool (such as .axial or .merge) can be used as “mesh” input for any of the mesh tools discussed in this manual.« less

Prosthetic mesh hernioplasty during laparoscopic radical prostatectomy.

PubMed

Teber, Dogu; Erdogru, Tibet; Zukosky, Derek; Frede, Thomas; Rassweiler, Jens

2005-06-01

To evaluate the role of simultaneous laparoscopic mesh prosthetic hernioplasty during laparoscopic radical prostatectomy (LRP), because 5% to 10% of candidates for radical prostatectomy present with a detectable inguinal hernia at their preoperative physical examination. Moreover, data have suggested a greater incidence of inguinal hernia after open radical prostatectomy. During 1035 LRP procedures, 50 laparoscopic mesh prosthetic hernioplasty procedures were performed in 37 patients (3.6%) for 13 bilateral and 24 unilateral inguinal hernias. We compared the outcome of LRP with simultaneous laparoscopic inguinal hernioplasty (group 1) with that of 37 match-paired patients treated by LRP alone (group 2). Both groups were matched according to age, prostate-specific antigen level, prostate volume, pathologic stage, and Gleason score. Perioperative parameters (ie, operative time, analgesic requirements) and postoperative results were analyzed. The patient age was 64.1 +/- 6.4 years versus 62.8 +/- 4.9 years old and had a body mass of 26.5 +/- 3.0 versus 27.4 +/- 3.2 kg/m2 in groups 1 and 2 (with and without laparoscopic hernioplasty), respectively. The mean operating time (221.9 versus 191.2 minutes, P = 0.011) and the total amount of narcotic analgesic requirements (26.8 mg versus 17.5 mg, P = 0.026) was significantly increased in the patients who underwent simultaneous laparoscopic inguinal hernia mesh repair. No statistically significant difference was found in the complication rate (4% versus 2%), median catheter time (7 days), and positive surgical margins (21.8%). Simultaneous repair of inguinal hernia during LRP using prosthetic mesh is feasible without adverse effects on surgical and functional parameters. Neither the transperitoneal nor extraperitoneal approach is associated with an increase in complications or morbidity. However, an extraperitoneal access allows an easier repair without the refixation of the peritoneum.

Tevatron beam position monitor upgrade

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolbers, Stephen; Banerjee, B.; Barker, B.

2005-05-01

The Tevatron Beam Position Monitor (BPM) readout electronics and software have been upgraded to improve measurement precision, functionality and reliability. The original system, designed and built in the early 1980's, became inadequate for current and future operations of the Tevatron. The upgraded system consists of 960 channels of new electronics to process analog signals from 240 BPMs, new front-end software, new online and controls software, and modified applications to take advantage of the improved measurements and support the new functionality. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiprotonmore » position measurements. Measurements using the new system are presented that demonstrate its improved resolution and overall performance.« less

Constrained CVT meshes and a comparison of triangular mesh generators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Hoa; Burkardt, John; Gunzburger, Max

2009-01-01

Mesh generation in regions in Euclidean space is a central task in computational science, and especially for commonly used numerical methods for the solution of partial differential equations, e.g., finite element and finite volume methods. We focus on the uniform Delaunay triangulation of planar regions and, in particular, on how one selects the positions of the vertices of the triangulation. We discuss a recently developed method, based on the centroidal Voronoi tessellation (CVT) concept, for effecting such triangulations and present two algorithms, including one new one, for CVT-based grid generation. We also compare several methods, including CVT-based methods, for triangulatingmore » planar domains. To this end, we define several quantitative measures of the quality of uniform grids. We then generate triangulations of several planar regions, including some having complexities that are representative of what one may encounter in practice. We subject the resulting grids to visual and quantitative comparisons and conclude that all the methods considered produce high-quality uniform grids and that the CVT-based grids are at least as good as any of the others.« less

Digital relief generation from 3D models

NASA Astrophysics Data System (ADS)

Wang, Meili; Sun, Yu; Zhang, Hongming; Qian, Kun; Chang, Jian; He, Dongjian

2016-09-01

It is difficult to extend image-based relief generation to high-relief generation, as the images contain insufficient height information. To generate reliefs from three-dimensional (3D) models, it is necessary to extract the height fields from the model, but this can only generate bas-reliefs. To overcome this problem, an efficient method is proposed to generate bas-reliefs and high-reliefs directly from 3D meshes. To produce relief features that are visually appropriate, the 3D meshes are first scaled. 3D unsharp masking is used to enhance the visual features in the 3D mesh, and average smoothing and Laplacian smoothing are implemented to achieve better smoothing results. A nonlinear variable scaling scheme is then employed to generate the final bas-reliefs and high-reliefs. Using the proposed method, relief models can be generated from arbitrary viewing positions with different gestures and combinations of multiple 3D models. The generated relief models can be printed by 3D printers. The proposed method provides a means of generating both high-reliefs and bas-reliefs in an efficient and effective way under the appropriate scaling factors.

Adaptive mesh optimization and nonrigid motion recovery based image registration for wide-field-of-view ultrasound imaging.

PubMed

Tan, Chaowei; Wang, Bo; Liu, Paul; Liu, Dong

2008-01-01

Wide field of view (WFOV) imaging mode obtains an ultrasound image over an area much larger than the real time window normally available. As the probe is moved over the region of interest, new image frames are combined with prior frames to form a panorama image. Image registration techniques are used to recover the probe motion, eliminating the need for a position sensor. Speckle patterns, which are inherent in ultrasound imaging, change, or become decorrelated, as the scan plane moves, so we pre-smooth the image to reduce the effects of speckle in registration, as well as reducing effects from thermal noise. Because we wish to track the movement of features such as structural boundaries, we use an adaptive mesh over the entire smoothed image to home in on areas with feature. Motion estimation using blocks centered at the individual mesh nodes generates a field of motion vectors. After angular correction of motion vectors, we model the overall movement between frames as a nonrigid deformation. The polygon filling algorithm for precise, persistence-based spatial compounding constructs the final speckle reduced WFOV image.

Airborne Tactical Data Network Gateways: Evaluating EPLRS’ Ability to Integrate With Wireless Meshed Networks

DTIC Science & Technology

2005-09-01

Computer Memory Card International Association PHY Physical PLI Position Location Information PLRS Position Location Reporting System PoP Point of...it is widely acknowledged that the JTRS program will not be providing any sustentative operational capability prior to FY’09. This reality has...Figure 5, and a man-packed antenna (AS- 3448/PSQ-4). Back-up (cryptographic key) memory is maintained by a traditional 9v 24

User Manual for the PROTEUS Mesh Tools

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Micheal A.; Shemon, Emily R

2016-09-19

PROTEUS is built around a finite element representation of the geometry for visualization. In addition, the PROTEUS-SN solver was built to solve the even-parity transport equation on a finite element mesh provided as input. Similarly, PROTEUS-MOC and PROTEUS-NEMO were built to apply the method of characteristics on unstructured finite element meshes. Given the complexity of real world problems, experience has shown that using commercial mesh generator to create rather simple input geometries is overly complex and slow. As a consequence, significant effort has been put into place to create multiple codes that help assist in the mesh generation and manipulation.more » There are three input means to create a mesh in PROTEUS: UFMESH, GRID, and NEMESH. At present, the UFMESH is a simple way to generate two-dimensional Cartesian and hexagonal fuel assembly geometries. The UFmesh input allows for simple assembly mesh generation while the GRID input allows the generation of Cartesian, hexagonal, and regular triangular structured grid geometry options. The NEMESH is a way for the user to create their own mesh or convert another mesh file format into a PROTEUS input format. Given that one has an input mesh format acceptable for PROTEUS, we have constructed several tools which allow further mesh and geometry construction (i.e. mesh extrusion and merging). This report describes the various mesh tools that are provided with the PROTEUS code giving both descriptions of the input and output. In many cases the examples are provided with a regression test of the mesh tools. The most important mesh tools for any user to consider using are the MT_MeshToMesh.x and the MT_RadialLattice.x codes. The former allows the conversion between most mesh types handled by PROTEUS while the second allows the merging of multiple (assembly) meshes into a radial structured grid. Note that the mesh generation process is recursive in nature and that each input specific for a given mesh tool (such as .axial or .merge) can be used as “mesh” input for any of the mesh tools discussed in this manual.« less

A microfabricated fringing field capacitive pH sensor with an integrated readout circuit

NASA Astrophysics Data System (ADS)

Arefin, Md Shamsul; Bulut Coskun, M.; Alan, Tuncay; Redoute, Jean-Michel; Neild, Adrian; Rasit Yuce, Mehmet

2014-06-01

This work presents a microfabricated fringe-field capacitive pH sensor using interdigitated electrodes and an integrated modulation-based readout circuit. The changes in capacitance of the sensor result from the permittivity changes due to pH variations and are converted to frequency shifts using a crossed-coupled voltage controlled oscillator readout circuit. The shift in resonant frequency of the readout circuit is 30.96 MHz for a change in pH of 1.0-5.0. The sensor can be used for the measurement of low pH levels, such as gastric acid, and can be integrated with electronic pills. The measurement results show high repeatability, low noise, and a stable output.

Image sensor with high dynamic range linear output

NASA Technical Reports Server (NTRS)

Yadid-Pecht, Orly (Inventor); Fossum, Eric R. (Inventor)

2007-01-01

Designs and operational methods to increase the dynamic range of image sensors and APS devices in particular by achieving more than one integration times for each pixel thereof. An APS system with more than one column-parallel signal chains for readout are described for maintaining a high frame rate in readout. Each active pixel is sampled for multiple times during a single frame readout, thus resulting in multiple integration times. The operation methods can also be used to obtain multiple integration times for each pixel with an APS design having a single column-parallel signal chain for readout. Furthermore, analog-to-digital conversion of high speed and high resolution can be implemented.

Crosstalk-free operation of multielement superconducting nanowire single-photon detector array integrated with single-flux-quantum circuit in a 0.1 W Gifford-McMahon cryocooler.

PubMed

Yamashita, Taro; Miki, Shigehito; Terai, Hirotaka; Makise, Kazumasa; Wang, Zhen

2012-07-15

We demonstrate the successful operation of a multielement superconducting nanowire single-photon detector (SSPD) array integrated with a single-flux-quantum (SFQ) readout circuit in a compact 0.1 W Gifford-McMahon cryocooler. A time-resolved readout technique, where output signals from each element enter the SFQ readout circuit with finite time intervals, revealed crosstalk-free operation of the four-element SSPD array connected with the SFQ readout circuit. The timing jitter and the system detection efficiency were measured to be 50 ps and 11.4%, respectively, which were comparable to the performance of practical single-pixel SSPD systems.

Focal plane infrared readout circuit

NASA Technical Reports Server (NTRS)

Pain, Bedabrata (Inventor)

2002-01-01

An infrared imager, such as a spectrometer, includes multiple infrared photodetectors and readout circuits for reading out signals from the photodetectors. Each readout circuit includes a buffered direct injection input circuit including a differential amplifier with active feedback provided through an injection transistor. The differential amplifier includes a pair of input transistors, a pair of cascode transistors and a current mirror load. Photocurrent from a photodetector can be injected onto an integration capacitor in the readout circuit with high injection efficiency at high speed. A high speed, low noise, wide dynamic range linear infrared multiplexer array for reading out infrared detectors with large capacitances can be achieved even when short exposure times are used. The effect of image lag can be reduced.

First case of mesh infection due to Coccidioides spp. and literature review of fungal mesh infections after hernia repair.

PubMed

Forrester, Joseph D; Gomez, Carlos A; Forrester, Jared A; Nguyen, Mike; Gregg, David; Deresinski, Stan; Banaei, Niaz; Weiser, Thomas G

2015-10-01

Fungal mesh infections are a rare complication of hernia repairs with mesh. The first case of Coccidioides spp. mesh infection is described, and a systematic literature review of all known fungal mesh infections was performed. Nine cases of fungal mesh infection are reviewed. Female and male patients are equally represented, median age is 49.5 years, and critical illness and preinfection antibiotic use were common. Fungal mesh infections are rare, but potentially fatal, complications of hernias repaired with mesh. © 2015 Blackwell Verlag GmbH.

Intra-oral soft tissue expansion and volume stability of onlay bone grafts.

PubMed

Abrahamsson, Peter

2011-01-01

Insufficient regeneration of missing bone and soft-tissue may present aesthetic or functional problems in patients indicated for dental implant surgery. Several techniques such as bone grafts, bone substitutes and guided tissue regeneration (GTR) have been described to rebuild a compromised alveolar ridge. Adequate soft-tissue coverage of grafted bone and titanium-mesh is important to avoid exposure which may result in loss of the bone graft. The general aim of this thesis was to evaluate use of an osmotic tissue expander for expanding intra-oral soft tissue--creating a surplus of soft tissue-- in preparation for onlay bone grafting. An experimental rabbit model was used in studies (I), (II) and (III). In (I) an osmotic soft-tissue expander was placed bilaterally on the lateral wall of the mandible via an extra-oral approach. After two weeks of expansion the rabbits were killed and specimens were collected for histology. No inflammatory reaction and no resorbtion of the cortical bone occured. The periosteum was expanded and new bone formation was seen in the edges of the expander. In (II) and (III) the expander was placed under the periosteum in the same way as in (I): bilaterally in 13 rabbits in (II) and unilaterally in 11 rabbits in (III). After two weeks of expansion the expander was identified and removed. In (II) particulated bone was placed at the recipient site protected by a titanium mesh in one site and a bio-resorbable mesh on the other site. In (III), DBBM particles and bone particles collected from the lateral border of the mandible separated by a collagen membrane was placed at the recipient site. The graft was protected by a pre-bent titanium mesh covered by a collagen membrane. After a healing period of 3 months specimens were collected for histological and SEM examination. New bone was growing in direct contact with the titanium mesh and bio resorbable mesh. The newly formed bone had the same calcium content as the mature bone in the base of the mandible. In the clinical study (IV) 20 patients were consecutively recruited and randomised into two groups. The experimental group (ten patients) had an osmotic soft tissue expander implanted. After two weeks of expansion the expander was removed and a particulated bone graft protected by a titanium mesh and a collagen membrane was fixed to the recipient site. Titanium implants were installed after a healing period of 6 months. The patients in the reference group had a bone block grafted from the anterior ramus fixated to the recipient site with one or two titanium mini screws. Implants were installed after a healing period of 6 months. A three dimensional optical measuring device was used to measure alterations in the soft tissue profile before each surgical procedure. The three-dimensional changes were then analysed on a PC. The results from the clinical study in patients confirmed the results from the experimental rabbit studies. The osmotic tissue expander expanded the soft tissue. Expander perforations of the soft tissue occurred in two patients. The optical measurements demonstrated a positive volume gain after soft tissue expansion and bone grafting. The expanded tissue could be used to cover a bone graft. There still was a risk of mesh exposure, even after soft tissue expansion, which occurred in two patients. In both groups, implants could be installed in the grafted bone in positions that would allow the crowns to fit aesthetically into the dental arch.

Hand-Held Electronic Gap-Measuring Tools

NASA Technical Reports Server (NTRS)

Sugg, F. E.; Thompson, F. W.; Aragon, L. A.; Harrington, D. B.

1985-01-01

Repetitive measurements simplified by tool based on LVDT operation. With fingers in open position, Gap-measuring tool rests on digital readout instrument. With fingers inserted in gap, separation alters inductance of linear variable-differential transformer in plastic handle. Originally developed for measuring gaps between surface tiles of Space Shuttle orbiter, tool reduces measurement time from 20 minutes per tile to 2 minutes. Also reduces possibility of damage to tiles during measurement. Tool has potential applications in mass production; helps ensure proper gap dimensions in assembly of refrigerator and car doors and also used to measure dimensions of components and to verify positional accuracy of components during progressive assembly operations.

Quadrant anode image sensor

NASA Technical Reports Server (NTRS)

Lampton, M.; Malina, R. F.

1976-01-01

A position-sensitive event-counting electronic readout system for microchannel plates (MCPs) is described that offers the advantages of high spatial resolution and fast time resolution. The technique relies upon a four-quadrant electron-collecting anode located behind the output face of the microchannel plate, so that the electron cloud from each detected event is partly intercepted by each of the four quadrants. The relative amounts of charge collected by each quadrant depend on event position, permitting each event to be localized with two ratio circuits. A prototype quadrant anode system for ion, electron, and extreme ultraviolet imaging is described. The spatial resolution achieved, about 10 microns, allows individual MCP channels to be distinguished.

An Adaptive Mesh Algorithm: Mapping the Mesh Variables

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scannapieco, Anthony J.

2016-07-25

Both thermodynamic and kinematic variables must be mapped. The kinematic variables are defined on a separate kinematic mesh; it is the duel mesh to the thermodynamic mesh. The map of the kinematic variables is done by calculating the contributions of kinematic variables on the old thermodynamic mesh, mapping the kinematic variable contributions onto the new thermodynamic mesh and then synthesizing the mapped kinematic variables on the new kinematic mesh. In this document the map of the thermodynamic variables will be described.

A discrete component low-noise preamplifier readout for a linear (1×16) SiC photodiode array

NASA Astrophysics Data System (ADS)

Kahle, Duncan; Aslam, Shahid; Herrero, Federico A.; Waczynski, Augustyn

2016-09-01

A compact, low-noise and inexpensive preamplifier circuit has been designed and fabricated to optimally readout a common cathode (1×16) channel 4H-SiC Schottky photodiode array for use in ultraviolet experiments. The readout uses an operational amplifier with 10 pF capacitor in the feedback loop in parallel with a low leakage switch for each of the channels. This circuit configuration allows for reiterative sample, integrate and reset. A sampling technique is given to remove Johnson noise, enabling a femtoampere level readout noise performance. Commercial-off-the-shelf acquisition electronics are used to digitize the preamplifier analog signals. The data logging acquisition electronics has a different integration circuit, which allows the bandwidth and gain to be independently adjusted. Using this readout, photoresponse measurements across the array between spectral wavelengths 200 nm and 370 nm are made to establish the array pixels external quantum efficiency, current responsivity and noise equivalent power.

Lithographed Superconducting Resonator Development for Next-Generation Frequency Multiplexing Readout of Transition-Edge Sensors

NASA Astrophysics Data System (ADS)

Faramarzi, F.; De Haan, T.; Kusaka, A.; Lee, A.; Neuhauser, B.; Plambeck, R.; Raum, C.; Suzuki, A.; Westbrook, B.

2018-03-01

Ground-based cosmic microwave background (CMB) experiments are undergoing a period of exponential growth. Current experiments are observing with 1000-10,000 detectors, and the next-generation experiment (CMB stage 4) is proposing to deploy approximately 500,000 detectors. This order of magnitude increase in detector count will require a new approach for readout electronics. We have developed superconducting resonators for next-generation frequency-domain multiplexing (fMUX) readout architecture. Our goal is to reduce the physical size of resonators, such that resonators and detectors can eventually be integrated on a single wafer. To reduce the size of these resonators, we have designed spiral inductors and interdigitated capacitors that resonate around 10-100 MHz, an order of magnitude higher frequency compared to current fMUX readout systems. The higher frequency leads to a wider bandwidth and would enable higher multiplexing factor than the current ˜ 50 detectors per readout channel. We will report on the simulation, fabrication method, characterization technique, and measurement of quality factor of these resonators.

Development of a front-end analog circuit for multi-channel SiPM readout and performance verification for various PET detector designs

NASA Astrophysics Data System (ADS)

Ko, Guen Bae; Yoon, Hyun Suk; Kwon, Sun Il; Lee, Chan Mi; Ito, Mikiko; Hong, Seong Jong; Lee, Dong Soo; Lee, Jae Sung

2013-03-01

Silicon photomultipliers (SiPMs) are outstanding photosensors for the development of compact imaging devices and hybrid imaging systems such as positron emission tomography (PET)/ magnetic resonance (MR) scanners because of their small size and MR compatibility. The wide use of this sensor for various types of scintillation detector modules is being accelerated by recent developments in tileable multichannel SiPM arrays. In this work, we present the development of a front-end readout module for multi-channel SiPMs. This readout module is easily extendable to yield a wider detection area by the use of a resistive charge division network (RCN). We applied this readout module to various PET detectors designed for use in small animal PET/MR, optical fiber PET/MR, and double layer depth of interaction (DOI) PET. The basic characteristics of these detector modules were also investigated. The results demonstrate that the PET block detectors developed using the readout module and tileable multi-channel SiPMs had reasonable performance.

A Discrete Component Low-Noise Preamplifier Readout for a Linear (1x16) SiC Photodiode Array

NASA Technical Reports Server (NTRS)

Kahle, Duncan; Aslam, Shahid; Herrero, Frederico A.; Waczynski, Augustyn

2016-01-01

A compact, low-noise and inexpensive preamplifier circuit has been designed and fabricated to optimally readout a common cathode (1x16) channel 4H-SiC Schottky photodiode array for use in ultraviolet experiments. The readout uses an operational amplifier with 10 pF capacitor in the feedback loop in parallel with a low leakage switch for each of the channels. This circuit configuration allows for reiterative sample, integrate and reset. A sampling technique is given to remove Johnson noise, enabling a femtoampere level readout noise performance. Commercial-off-the-shelf acquisition electronics are used to digitize the preamplifier analogue signals. The data logging acquisition electronics has a different integration circuit, which allows the bandwidth and gain to be independently adjusted. Using this readout, photoresponse measurements across the array between spectral wavelengths 200 nm and 370 nm are made to establish the array pixels external quantum efficiency, current responsivity and noise equivalent power.

Enabling Large Focal Plane Arrays Through Mosaic Hybridization

NASA Technical Reports Server (NTRS)

Miller, TImothy M.; Jhabvala, Christine A.; Leong, Edward; Costen, Nicholas P.; Sharp, Elmer; Adachi, Tomoko; Benford, Dominic

2012-01-01

We have demonstrated advances in mosaic hybridization that will enable very large format far-infrared detectors. Specifically we have produced electrical detector models via mosaic hybridization yielding superconducting circuit paths by hybridizing separately fabricated sub-units onto a single detector unit. The detector model was made on a 100mm diameter wafer while four model readout quadrant chips were made from a separate 100mm wafer. The individually fabricated parts were hybridized using a flip-chip bonder to assemble the detector-readout stack. Once all of the hybridized readouts were in place, a single, large and thick silicon substrate was placed on the stack and attached with permanent epoxy to provide strength and a Coefficient of Thermal Expansion match to the silicon components underneath. Wirebond pads on the readout chips connect circuits to warm readout electronics; and were used to validate the successful superconducting electrical interconnection of the model mosaic-hybrid detector. This demonstration is directly scalable to 150 mm diameter wafers, enabling pixel areas over ten times the area currently available.

Data acquisition and processing in the ATLAS tile calorimeter phase-II upgrade demonstrator

NASA Astrophysics Data System (ADS)

Valero, A.; Tile Calorimeter System, ATLAS

2017-10-01

The LHC has planned a series of upgrades culminating in the High Luminosity LHC which will have an average luminosity 5-7 times larger than the nominal Run 2 value. The ATLAS Tile Calorimeter will undergo an upgrade to accommodate the HL-LHC parameters. The TileCal readout electronics will be redesigned, introducing a new readout strategy. A Demonstrator program has been developed to evaluate the new proposed readout architecture and prototypes of all the components. In the Demonstrator, the detector data received in the Tile PreProcessors (PPr) are stored in pipeline buffers and upon the reception of an external trigger signal the data events are processed, packed and readout in parallel through the legacy ROD system, the new Front-End Link eXchange system and an ethernet connection for monitoring purposes. This contribution describes in detail the data processing and the hardware, firmware and software components of the TileCal Demonstrator readout system.

Enabling Large Focal Plane Arrays through Mosaic Hybridization

NASA Technical Reports Server (NTRS)

Miller, Timothy M.; Jhabvala, Christine A.; Costen, Nick; Benford, Dominic J.

2012-01-01

We have demonstrated the hybridization of large mosaics of far-infrared detectors, joining separately fabricated sub-units into a single unit on a single, large substrate. We produced a single detector mockup on a 100mm diameter wafer and four mockup readout quadrant chips from a separate 100mm wafer. The individually fabricated parts were hybridized using a Suss FC150 flip chip bonder to assemble the detector-readout stack. Once all of the hybridized readouts were in place, a single, large and thick silicon substrate was placed on the stack and attached with permanent epoxy to provide strength and a Coefficient of Thermal Expansion (CTE) match to the silicon components underneath. Wirebond pads on the readout chips connect circuits to warm readout electronics; and were used to validate the successful superconducting electrical interconnection of the mockup mosaic-hybridized detector. This demonstration is directly scalable to 150 mm diameter wafers, enabling pixel areas over ten times the area currently demonstrated.

Evaluation on Compressive Characteristics of Medical Stents Applied by Mesh Structures

NASA Astrophysics Data System (ADS)

Hirayama, Kazuki; He, Jianmei

2017-11-01

There are concerns about strength reduction and fatigue fracture due to stress concentration in currently used medical stents. To address these problems, meshed stents applied by mesh structures were interested for achieving long life and high strength perfromance of medical stents. The purpose of this study is to design basic mesh shapes to obatin three dimensional (3D) meshed stent models for mechanical property evaluation. The influence of introduced design variables on compressive characteristics of meshed stent models are evaluated through finite element analysis using ANSYS Workbench code. From the analytical results, the compressive stiffness are changed periodically with compressive directions, average results need to be introduced as the mean value of compressive stiffness of meshed stents. Secondly, compressive flexibility of meshed stents can be improved by increasing the angle proportional to the arm length of the mesh basic shape. By increasing the number of basic mesh shapes arranged in stent’s circumferential direction, compressive rigidity of meshed stent tends to be increased. Finaly reducing the mesh line width is found effective to improve compressive flexibility of meshed stents.

Protective constriction of coronary vein grafts with knitted nitinol

PubMed Central

Moodley, Loven; Franz, Thomas; Human, Paul; Wolf, Michael F.; Bezuidenhout, Deon; Scherman, Jacques; Zilla, Peter

2013-01-01

OBJECTIVES Different flow patterns and shear forces were shown to cause significantly more luminal narrowing and neointimal tissue proliferation in coronary than in infrainguinal vein grafts. As constrictive external mesh support of vein grafts led to the complete suppression of intimal hyperplasia (IH) in infrainguinal grafts, we investigated whether mesh constriction is equally effective in the coronary position. METHODS Eighteen senescent Chacma baboons (28.8 ± 3.6 kg) received aorto-coronary bypass grafts to the left anterior descending artery (LAD). Three groups of saphenous vein grafts were compared: untreated controls (CO); fibrin sealant-sprayed controls (CO + FS) and nitinol mesh-constricted grafts (ME + FS). Meshes consisted of pulse-compliant, knitted nitinol (eight needles; 50 μm wire thickness; 3.4 mm resting inner diameter, ID) spray attached to the vein grafts with FS. After 180 days of implantation, luminal dimensions and IH were analysed using post-explant angiography and macroscopic and histological image analysis. RESULTS At implantation, the calibre mismatch between control grafts and the LAD expressed as cross-sectional quotient (Qc) was pronounced [Qc = 0.21 ± 0.07 (CO) and 0.18 ± 0.05 (CO + FS)]. Mesh constriction resulted in a 29 ± 7% reduction of the outer diameter of the vein grafts from 5.23 ± 0.51 to 3.68 ± 0 mm, significantly reducing the calibre discrepancy to a Qc of 0.41 ± 0.17 (P < 0.02). After 6 months of implantation, explant angiography showed distinct luminal irregularities in control grafts (ID difference between widest and narrowest segment 74 ± 45%), while diameter variations were mild in mesh-constricted grafts. In all control grafts, thick neointimal tissue was present [600 ± 63 μm (CO); 627 ± 204 μm (CO + FS)] as opposed to thin, eccentric layers of 249 ± 83 μm in mesh-constricted grafts (ME + FS; P < 0.002). The total wall thickness had increased by 363 ± 39% (P < 0.00001) in CO and 312 ± 61% (P < 0.00001) in CO + FS vs 82 ± 61% in ME + FS (P < 0.007). CONCLUSIONS In a senescent non-human primate model for coronary artery bypass grafts, constrictive, external mesh support of saphenous veins with knitted nitinol prevented focal, irregular graft narrowing and suppressed neointimal tissue proliferation by a factor of 2.5. The lower degree of suppression of IH compared with previous infrainguinal grafts coincided with a lesser reduction of calibre mismatch in the coronary grafts. PMID:23295444

Mesh control information of windmill designed by Solidwork program

NASA Astrophysics Data System (ADS)

Mulyana, T.; Sebayang, D.; Rafsanjani, A. M. D.; Adani, J. H. D.; Muhyiddin, Y. S.

2017-12-01

This paper presents the mesh control information imposed on the windmill already designed. The accuracy of Simulation results is influenced by the quality of the created mesh. However, compared to the quality of the mesh is made, the simulation time running will be done software also increases. The smaller the size of the elements created when making the mesh, the better the mesh quality will be generated. When adjusting the mesh size, there is a slider that acts as the density regulator of the element. SolidWorks Simulation also has Mesh Control facility. Features that can adjust mesh density only in the desired part. The best results of mesh control obtained for both static and thermal simulation have ratio 1.5.

Optoelectronic associative recall using motionless-head parallel readout optical disk

NASA Astrophysics Data System (ADS)

Marchand, P. J.; Krishnamoorthy, A. V.; Ambs, P.; Esener, S. C.

1990-12-01

High data rates, low retrieval times, and simple implementation are presently shown to be obtainable by means of a motionless-head 2D parallel-readout system for optical disks. Since the optical disk obviates mechanical head motions for access, focusing, and tracking, addressing is performed exclusively through the disk's rotation. Attention is given to a high-performance associative memory system configuration which employs a parallel readout disk.

A charge- and energy-conserving implicit, electrostatic particle-in-cell algorithm on mapped computational meshes

NASA Astrophysics Data System (ADS)

Chacón, L.; Chen, G.; Barnes, D. C.

2013-01-01

We describe the extension of the recent charge- and energy-conserving one-dimensional electrostatic particle-in-cell algorithm in Ref. [G. Chen, L. Chacón, D.C. Barnes, An energy- and charge-conserving, implicit electrostatic particle-in-cell algorithm, Journal of Computational Physics 230 (2011) 7018-7036] to mapped (body-fitted) computational meshes. The approach maintains exact charge and energy conservation properties. Key to the algorithm is a hybrid push, where particle positions are updated in logical space, while velocities are updated in physical space. The effectiveness of the approach is demonstrated with a challenging numerical test case, the ion acoustic shock wave. The generalization of the approach to multiple dimensions is outlined.

Construction and temporal behaviour study of multi RLC intense light pulses for dermatological applications.

PubMed

Hamoudi, Walid K; Ismail, Raid A; Shakir, Hussein A

2017-10-01

Driving a flash lamp in an intense pulsed light system requires a high-voltage DC power supply, capacitive energy storage and a flash lamp triggering unit. Single, double, triple and quadruple-mesh discharge and triggering circuits were constructed to provide intense light pulses of variable energy and time durations. The system was treated as [Formula: see text] circuit in some cases and [Formula: see text] circuit in others with a light pulse profile following the temporal behaviour of the exciting current pulse. Distributing the energy delivered to one lamp onto a number of LC meshes permitted longer current pulses, and consequently increased the light pulse length. Positive results were obtained when using the system to treat skin wrinkles.

The earliest herbivorous marine reptile and its remarkable jaw apparatus

PubMed Central

Chun, Li; Rieppel, Olivier; Long, Cheng; Fraser, Nicholas C.

2016-01-01

Newly discovered fossils of the Middle Triassic reptile Atopodentatus unicus call for a radical reassessment of its feeding behavior. The skull displays a pronounced hammerhead shape that was hitherto unknown. The long, straight anterior edges of both upper and lower jaws were lined with batteries of chisel-shaped teeth, whereas the remaining parts of the jaw rami supported densely packed needle-shaped teeth forming a mesh. The evidence indicates a novel feeding mechanism wherein the chisel-shaped teeth were used to scrape algae off the substrate, and the plant matter that was loosened was filtered from the water column through the more posteriorly positioned tooth mesh. This is the oldest record of herbivory within marine reptiles. PMID:27386529

Central FPGA-based destination and load control in the LHCb MHz event readout

NASA Astrophysics Data System (ADS)

Jacobsson, R.

2012-10-01

The readout strategy of the LHCb experiment is based on complete event readout at 1 MHz. A set of 320 sub-detector readout boards transmit event fragments at total rate of 24.6 MHz at a bandwidth usage of up to 70 GB/s over a commercial switching network based on Gigabit Ethernet to a distributed event building and high-level trigger processing farm with 1470 individual multi-core computer nodes. In the original specifications, the readout was based on a pure push protocol. This paper describes the proposal, implementation, and experience of a non-conventional mixture of a push and a pull protocol, akin to credit-based flow control. An FPGA-based central master module, partly operating at the LHC bunch clock frequency of 40.08 MHz and partly at a double clock speed, is in charge of the entire trigger and readout control from the front-end electronics up to the high-level trigger farm. One FPGA is dedicated to controlling the event fragment packing in the readout boards, the assignment of the farm node destination for each event, and controls the farm load based on an asynchronous pull mechanism from each farm node. This dynamic readout scheme relies on generic event requests and the concept of node credit allowing load control and trigger rate regulation as a function of the global farm load. It also allows the vital task of fast central monitoring and automatic recovery in-flight of failing nodes while maintaining dead-time and event loss at a minimum. This paper demonstrates the strength and suitability of implementing this real-time task for a very large distributed system in an FPGA where no random delays are introduced, and where extreme reliability and accurate event accounting are fundamental requirements. It was in use during the entire commissioning phase of LHCb and has been in faultless operation during the first two years of physics luminosity data taking.

Changes in pelvic organ prolapse mesh mechanical properties following implantation in rats.

PubMed

Ulrich, Daniela; Edwards, Sharon L; Alexander, David L J; Rosamilia, Anna; Werkmeister, Jerome A; Gargett, Caroline E; Letouzey, Vincent

2016-02-01

Pelvic organ prolapse (POP) is a multifactorial disease that manifests as the herniation of the pelvic organs into the vagina. Surgical methods for prolapse repair involve the use of a synthetic polypropylene mesh. The use of this mesh has led to significantly higher anatomical success rates compared with native tissue repairs, and therefore, despite recent warnings by the Food and Drug Administration regarding the use of vaginal mesh, the number of POP mesh surgeries has increased over the last few years. However, mesh implantation is associated with higher postsurgery complications, including pain and erosion, with higher consecutive rates of reoperation when placed vaginally. Little is known on how the mechanical properties of the implanted mesh itself change in vivo. It is assumed that the mechanical properties of these meshes remain unchanged, with any differences in mechanical properties of the formed mesh-tissue complex attributed to the attached tissue alone. It is likely that any changes in mesh mechanical properties that do occur in vivo will have an impact on the biomechanical properties of the formed mesh-tissue complex. The objective of the study was to assess changes in the multiaxial mechanical properties of synthetic clinical prolapse meshes implanted abdominally for up to 90 days, using a rat model. Another objective of the study was to assess the biomechanical properties of the formed mesh-tissue complex following implantation. Three nondegradable polypropylene clinical synthetic mesh types for prolapse repair (Gynemesh PS, Polyform Lite, and Restorelle) and a partially degradable polypropylene/polyglecaprone mesh (UltraPro) were mechanically assessed before and after implantation (n = 5/ mesh type) in Sprague Dawley rats for 30 (Gynemesh PS, Polyform Lite, and Restorelle) and 90 (UltraPro and Polyform Lite) days. Stiffness and permanent extension following cyclic loading, and breaking load, of the preimplanted mesh types, explanted mesh-tissue complexes, and explanted meshes were assessed using a multi-axial (ball-burst) method. The 4 clinical meshes varied from each other in weight, thickness, porosity, and pore size and showed significant differences in stiffness and breaking load before implantation. Following 30 days of implantation, the mechanical properties of some mesh types altered, with significant decreases in mesh stiffness and breaking load, and increased permanent extension. After 90 days these changes were more obvious, with significant decreases in stiffness and breaking load and increased permanent extension. Similar biomechanical properties of formed mesh-tissue complexes were observed for mesh types of different preimplant stiffness and structure after 90 days implantation. This is the first study to report on intrinsic changes in the mechanical properties of implanted meshes and how these changes have an impact on the estimated tissue contribution of the formed mesh-tissue complex. Decreased mesh stiffness, strength, and increased permanent extension following 90 days of implantation increase the biomechanical contribution of the attached tissue of the formed mesh-tissue complex more than previously thought. This needs to be considered when using meshes for prolapse repair. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Radial cold trap

DOEpatents

Grundy, Brian R.

1981-01-01

The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume.

Radial cold trap

DOEpatents

Grundy, B.R.

1981-09-29

The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume. 2 figs.

Association Between the Amount of Vaginal Mesh Used With Mesh Erosions and Repeated Surgery After Repairing Pelvic Organ Prolapse and Stress Urinary Incontinence.

PubMed

Chughtai, Bilal; Barber, Matthew D; Mao, Jialin; Forde, James C; Normand, Sharon-Lise T; Sedrakyan, Art

2017-03-01

Mesh, a synthetic graft, has been used in pelvic organ prolapse (POP) repair and stress urinary incontinence (SUI) to augment and strengthen weakened tissue. Polypropylene mesh has come under scrutiny by the US Food and Drug Administration. To examine the rates of mesh complications and invasive reintervention after the placement of vaginal mesh for POP repair or SUI surgery. This investigation was an observational cohort study at inpatient and ambulatory surgery settings in New York State. Participants were women who underwent transvaginal repair for POP or SUI with mesh between January 1, 2008, and December 31, 2012, and were followed up through December 31, 2013. They were divided into the following 4 groups based on the amount of mesh exposure: transvaginal POP repair surgery with mesh and concurrent sling use (vaginal mesh plus sling group), transvaginal POP repair with mesh and no concurrent sling use (vaginal mesh group), transvaginal POP repair without mesh but concurrent sling use for SUI (POP sling group), and sling for SUI alone (SUI sling group). The primary outcome was the occurrence of mesh complications and repeated invasive intervention within 1 year after the initial mesh implantation. A time-to-event analysis was performed to examine the occurrence of mesh erosions and subsequent reintervention. Secondary analyses of an age association (<65 vs ≥65 years) were conducted. The study identified 41 604 women who underwent 1 of the 4 procedures. The mean (SD) age of women at their initial mesh implantation was 56.2 (13.0) years. The highest risk of erosions was found in the vaginal mesh plus sling group (2.72%; 95% CI, 2.31%-3.21%) and the lowest in the SUI sling group (1.57%; 95% CI, 1.41%-1.74%). The risk of repeated surgery with concomitant erosion diagnosis was also the highest in the vaginal mesh plus sling group (2.13%; 95% CI, 1.76%-2.56%) and the lowest in the SUI sling group (1.16%; 95% CI, 1.03%-1.31%). The combined use of POP mesh and SUI mesh sling was associated with the highest erosion and repeated intervention risk, while mesh sling alone had the lowest erosion and repeated intervention risk. There is evidence for a dose-response relationship between the amount of mesh used and subsequent mesh erosions, complications, and invasive repeated intervention.

Design and Measurement of a Low-Noise 64-Channels Front-End Readout ASIC for CdZnTe Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gan, Bo; Wei, Tingcun; Gao, Wu

Cadmium zinc telluride (CdZnTe) detectors, as one of the principal detectors for the next-generation X-ray and γ-ray imagers, have high energy resolution and supporting electrode patterning in the radiation environment at room-temperature. In the present, a number of internationally renowned research institutions and universities are actively using these detector systems to carry out researches of energy spectrum analysis, medical imaging, materials characterization, high-energy physics, nuclear plant monitoring, and astrophysics. As the most important part of the readout system for the CdZnTe detector, the front-end readout application specific integrated circuit (ASIC) would have an important impact on the performances of themore » whole detector system. In order to ensure the small signal to noise ratio (SNR) and sufficient range of the output signal, it is necessary to design a front-end readout ASIC with very low noise and very high dynamic range. In addition, radiation hardness should be considered when the detectors are utilized in the space applications and high energy physics experiments. In this paper, we present measurements and performances of a novel multi-channel radiation-hardness low-noise front-end readout ASIC for CdZnTe detectors. The readout circuits in each channel consist of charge sensitive amplifier, leakage current compensation circuit (LCC), CR-RC shaper, S-K filter, inverse proportional amplifier, peak detect and hold circuit (PDH), discriminator and trigger logic, time sequence control circuit and driving buffer. All of 64 readout channels' outputs enter corresponding inputs of a 64 channel multiplexer. The output of the mux goes directly out of the chip via the output buffer. The 64-channel readout ASIC is implemented using the TSMC 0.35 μm mixed-signal CMOS technology. The die size of the prototype chip is 2.7 mm x 8 mm. At room temperature, the equivalent noise level of a typical channel reaches 66 e{sup -} (rms) at zero farad for a power consumption of 8 mW per channel. The linearity error is lower than 1% and the overall gain of the readout channel is 165 V/pC. The crosstalk between the channels is less than 3%. By connecting the readout ASIC to a CdZnTe detector, we obtained a γ-ray spectrum, the energy resolution is 5.1% at the 59.5-keV line of {sup 241}Am source. (authors)« less

Documentation for MeshKit - Reactor Geometry (&mesh) Generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jain, Rajeev; Mahadevan, Vijay

2015-09-30

This report gives documentation for using MeshKit’s Reactor Geometry (and mesh) Generator (RGG) GUI and also briefly documents other algorithms and tools available in MeshKit. RGG is a program designed to aid in modeling and meshing of complex/large hexagonal and rectilinear reactor cores. RGG uses Argonne’s SIGMA interfaces, Qt and VTK to produce an intuitive user interface. By integrating a 3D view of the reactor with the meshing tools and combining them into one user interface, RGG streamlines the task of preparing a simulation mesh and enables real-time feedback that reduces accidental scripting mistakes that could waste hours of meshing.more » RGG interfaces with MeshKit tools to consolidate the meshing process, meaning that going from model to mesh is as easy as a button click. This report is designed to explain RGG v 2.0 interface and provide users with the knowledge and skills to pilot RGG successfully. Brief documentation of MeshKit source code, tools and other algorithms available are also presented for developers to extend and add new algorithms to MeshKit. RGG tools work in serial and parallel and have been used to model complex reactor core models consisting of conical pins, load pads, several thousands of axially varying material properties of instrumentation pins and other interstices meshes.« less

The Detector System for the Stratospheric Kinetic Inductance Polarimeter ( Skip)

NASA Astrophysics Data System (ADS)

Johnson, B. R.; Ade, P. A. R.; Araujo, D.; Bradford, K. J.; Chapman, D.; Day, P. K.; Didier, J.; Doyle, S.; Eriksen, H. K.; Flanigan, D.; Groppi, C.; Hillbrand, S.; Jones, G.; Limon, M.; Mauskopf, P.; McCarrick, H.; Miller, A.; Mroczkowski, T.; Reichborn-Kjennerud, B.; Smiley, B.; Sobrin, J.; Wehus, I. K.; Zmuidzinas, J.

2014-09-01

The stratospheric kinetic inductance polarimeter is a proposed balloon-borne experiment designed to study the cosmic microwave background, the cosmic infrared background and Galactic dust emission by observing 1,133 deg of sky in the Northern Hemisphere with launches from Kiruna, Sweden. The instrument contains 2,317 single-polarization, horn-coupled, aluminum lumped-element kinetic inductance detectors ( Lekids). The Lekids will be maintained at 100 mK with an adiabatic demagnetization refrigerator. The polarimeter operates in two configurations, one sensitive to a spectral band centered on 150 GHz and the other sensitive to 260 and 350 GHz bands. The detector readout system is based on the ROACH-1 board, and the detectors will be biased below 300 MHz. The detector array is fed by an F/2.4 crossed-Dragone telescope with a 500 mm aperture yielding a 15 arcmin FWHM beam at 150 GHz. To minimize detector loading and maximize sensitivity, the entire optical system will be cooled to 1 K. Linearly polarized sky signals will be modulated with a metal-mesh half-wave plate that is mounted at the telescope aperture and rotated by a superconducting magnetic bearing. The observation program consists of at least two, 5-day flights beginning with the 150 GHz observations.

The Stratospheric Kinetic Inductance Polarimeter (SKIP)

NASA Astrophysics Data System (ADS)

Flanigan, Daniel; Ade, P.; Araujo, D.; Bradford, K. J.; Chapman, D.; Che, G.; Day, P.; Didier, J.; Doyle, S.; Eriksen, H.; Groppi, C. E.; Hillbrand, S. N.; Johnson, B.; Jones, G.; Limon, M.; Mauskopf, P.; McCarrick, H.; Miller, A. D.; Mroczkowski, T.; Reichborn-Kjennerud, B.; Smiley, B.; Sobrin, J.; Wehus, I. K.; Zmuidzinas, J.

2014-01-01

We discuss the Stratospheric Kinetic Inductance Polarimeter (SKIP). SKIP is a proposed balloon-borne experiment designed to study the cosmic microwave background, the cosmic infrared background, and Galactic dust emission by observing 1100 square degrees of sky in the Northern Hemisphere with launches from Kiruna, Sweden. The instrument contains 2317 single-polarization, horn-coupled, aluminum lumped-element kinetic inductance detectors (LEKIDs), which will be maintained at 100 mK by an adiabatic demagnetization refrigerator. The polarimeter will operate in two configurations, one sensitive to a spectral band centered on 150 GHz and the other sensitive to 260 and 350 GHz bands. The detector readout system is based on the ROACH-1 board, and the detectors will be biased below 300 MHz. The detector array is fed by an F/2.4 crossed-Dragone telescope with a 500 mm aperture yielding a 15 arcminute full-width half-maximum beam at 150 GHz. To minimize detector loading and maximize sensitivity, the entire optical system will be cooled to 1 K. Linearly polarized sky signals will be modulated with a metal-mesh half-wave plate that is mounted at the telescope aperture and is rotated on a superconducting magnetic bearing. The observation program consists of two or more five-day flights, and 150 GHz observations are planned to begin in 2017.

A novel fast-neutron detector concept for energy-selective imaging and imaging spectroscopy.

PubMed

Cortesi, M; Dangendorf, V; Zboray, R; Prasser, H-M

2014-07-01

We present and discuss the operational principle of a new fast-neutron detector concept suitable for either energy-selective imaging or for imaging spectroscopy. The detector is comprised of a series of energy-selective stacks of converter foils immersed in a noble-gas based mixture, coupled to a position-sensitive charge readout. Each foil in the various stacks is made of two layers of different thicknesses, fastened together: a hydrogen-rich (plastic) layer for neutron-to-proton conversion, and a hydrogen-free coating to selectively stop/absorb the recoil protons below a certain energy cut-off. The neutron-induced recoil protons, that escape the converter foils, release ionization electrons in the gas gaps between consecutive foils. The electrons are then drifted towards and localized by a position-sensitive charge amplification and readout stage. Comparison of the images detected by stacks with different energy cut-offs allows energy-selective imaging. Neutron energy spectrometry is realized by analyzing the responses of a sufficient large number of stacks of different energy response and unfolding techniques. In this paper, we present the results of computer simulation studies and discuss the expected performance of the new detector concept. Potential applications in various fields are also briefly discussed, in particularly, the application of energy-selective fast-neutron imaging for nuclear safeguards application, with the aim of determining the plutonium content in Mixed Oxide (MOX) fuels.

A combined time-of-flight and depth-of-interaction detector for total-body positron emission tomography.

PubMed

Berg, Eric; Roncali, Emilie; Kapusta, Maciej; Du, Junwei; Cherry, Simon R

2016-02-01

In support of a project to build a total-body PET scanner with an axial field-of-view of 2 m, the authors are developing simple, cost-effective block detectors with combined time-of-flight (TOF) and depth-of-interaction (DOI) capabilities. This work focuses on investigating the potential of phosphor-coated crystals with conventional PMT-based block detector readout to provide DOI information while preserving timing resolution. The authors explored a variety of phosphor-coating configurations with single crystals and crystal arrays. Several pulse shape discrimination techniques were investigated, including decay time, delayed charge integration (DCI), and average signal shapes. Pulse shape discrimination based on DCI provided the lowest DOI positioning error: 2 mm DOI positioning error was obtained with single phosphor-coated crystals while 3-3.5 mm DOI error was measured with the block detector module. Minimal timing resolution degradation was observed with single phosphor-coated crystals compared to uncoated crystals, and a timing resolution of 442 ps was obtained with phosphor-coated crystals in the block detector compared to 404 ps without phosphor coating. Flood maps showed a slight degradation in crystal resolvability with phosphor-coated crystals; however, all crystals could be resolved. Energy resolution was degraded by 3%-7% with phosphor-coated crystals compared to uncoated crystals. These results demonstrate the feasibility of obtaining TOF-DOI capabilities with simple block detector readout using phosphor-coated crystals.

Development and characterization of high-resolution neutron pixel detectors based on Timepix read-out chips

NASA Astrophysics Data System (ADS)

Krejci, F.; Zemlicka, J.; Jakubek, J.; Dudak, J.; Vavrik, D.; Köster, U.; Atkins, D.; Kaestner, A.; Soltes, J.; Viererbl, L.; Vacik, J.; Tomandl, I.

2016-12-01

Using a suitable isotope such as 6Li and 10B semiconductor hybrid pixel detectors can be successfully adapted for position sensitive detection of thermal and cold neutrons via conversion into energetic light ions. The adapted devices then typically provides spatial resolution at the level comparable to the pixel pitch (55 μm) and sensitive area of about few cm2. In this contribution, we describe further progress in neutron imaging performance based on the development of a large-area hybrid pixel detector providing practically continuous neutron sensitive area of 71 × 57 mm2. The measurements characterising the detector performance at the cold neutron imaging instrument ICON at PSI and high-flux imaging beam-line Neutrograph at ILL are presented. At both facilities, high-resolution high-contrast neutron radiography with the newly developed detector has been successfully applied for objects which imaging were previously difficult with hybrid pixel technology (such as various composite materials, objects of cultural heritage etc.). Further, a significant improvement in the spatial resolution of neutron radiography with hybrid semiconductor pixel detector based on the fast read-out Timepix-based detector is presented. The system is equipped with a thin planar 6LiF convertor operated effectively in the event-by-event mode enabling position sensitive detection with spatial resolution better than 10 μm.

Comparative analysis of histopathologic effects of synthetic meshes based on material, weight, and pore size in mice.

PubMed

Orenstein, Sean B; Saberski, Ean R; Kreutzer, Donald L; Novitsky, Yuri W

2012-08-01

While synthetic prosthetics have essentially become mandatory for hernia repair, mesh-induced chronic inflammation and scarring can lead to chronic pain and limited mobility. Mesh propensity to induce such adverse effects is likely related to the prosthetic's material, weight, and/or pore size. We aimed to compare histopathologic responses to various synthetic meshes after short- and long-term implantations in mice. Samples of macroporous polyester (Parietex [PX]), heavyweight microporous polypropylene (Trelex[TX]), midweight microporous polypropylene (ProLite[PL]), lightweight macroporous polypropylene (Ultrapro[UP]), and expanded polytetrafluoroethylene (DualMesh[DM]) were implanted subcutaneously in mice. Four and 12 wk post-implantation, meshes were assessed for inflammation, foreign body reaction (FBR), and fibrosis. All meshes induced varying levels of inflammatory responses. PX induced the greatest inflammatory response and marked FBR. DM induced moderate FBR and a strong fibrotic response with mesh encapsulation at 12 wk. UP and PL had the lowest FBR, however, UP induced a significant chronic inflammatory response. Although inflammation decreased slightly for TX, marked FBR was present throughout the study. Of the three polypropylene meshes, fibrosis was greatest for TX and slightly reduced for PL and UP. For UP and PL, there was limited fibrosis within each mesh pore. Polyester mesh induced the greatest FBR and lasting chronic inflammatory response. Likewise, marked fibrosis and encapsulation was seen surrounding ePTFE. Heavier polypropylene meshes displayed greater early and persistent fibrosis; the reduced-weight polypropylene meshes were associated with the least amount of fibrosis. Mesh pore size was inversely proportional to bridging fibrosis. Moreover, reduced-weight polypropylene meshes demonstrated the smallest FBR throughout the study. Overall, we demonstrated that macroporous, reduced-weight polypropylene mesh exhibited the highest degree of biocompatibility at sites of mesh implantation. Copyright © 2012 Elsevier Inc. All rights reserved.

Proposal to upgrade the MIPP data acquisition system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, W.; Carey, D.; Johnstone, C.

2005-03-01

The MIPP TPC is the largest contributor to the MIPP event size by far. Its readout system and electronics were designed in the 1990's and limit it to a readout rate of 60 Hz in simple events and {approx} 20 Hz in complicated events. With the readout chips designed for the ALICE collaboration at the LHC, we propose a low cost effective scheme of upgrading the MIPP data acquisition speed to 3000 Hz.

An application specific integrated circuit based multi-anode microchannel array readout system

NASA Technical Reports Server (NTRS)

Smeins, Larry G.; Stechman, John M.; Cole, Edward H.

1991-01-01

Size reduction of two new multi-anode microchannel array (MAMA) readout systems is described. The systems are based on two analog and one digital application specific integrated circuits (ASICs). The new readout systems reduce volume over previous discrete designs by 80 percent while improving electrical performance on virtually every significant parameter. Emphasis is made on the packaging used to achieve the volume reduction. Surface mount technology (SMT) is combined with modular construction for the analog portion of the readout. SMT reliability concerns and the board area impact of MIL SPEC SMT components is addressed. Package selection for the analog ASIC is discussed. Future sytems will require even denser packaging and the volume reduction progression is shown.

Ionization Readout Electronics for SuperCDMS SNOLAB Employing a HEMT Front-End

NASA Astrophysics Data System (ADS)

Partridge, R.

2014-09-01

The SuperCDMS SNOLAB experiment seeks to deploy 200 kg of cryogenic Ge detectors employing phonon and ionization readout to identify dark matter interactions. One of the design challenges for the experiment is to provide amplification of the high impedance ionization signal while minimizing power dissipation and noise. This paper describes the design and expected performance of the ionization readout being developed for an engineering model of the SuperCDMS SNOLAB Ge Tower System. The readout features the use of a low-noise HEMT front end transistor operating at 4 K to achieve a power dissipation of 100 W per channel, local grounding to minimize noise injection, and biasing circuitry that allows precise control of the HEMT operating point.

What is the evidence for the use of biologic or biosynthetic meshes in abdominal wall reconstruction?

PubMed

Köckerling, F; Alam, N N; Antoniou, S A; Daniels, I R; Famiglietti, F; Fortelny, R H; Heiss, M M; Kallinowski, F; Kyle-Leinhase, I; Mayer, F; Miserez, M; Montgomery, A; Morales-Conde, S; Muysoms, F; Narang, S K; Petter-Puchner, A; Reinpold, W; Scheuerlein, H; Smietanski, M; Stechemesser, B; Strey, C; Woeste, G; Smart, N J

2018-04-01

Although many surgeons have adopted the use of biologic and biosynthetic meshes in complex abdominal wall hernia repair, others have questioned the use of these products. Criticism is addressed in several review articles on the poor standard of studies reporting on the use of biologic meshes for different abdominal wall repairs. The aim of this consensus review is to conduct an evidence-based analysis of the efficacy of biologic and biosynthetic meshes in predefined clinical situations. A European working group, "BioMesh Study Group", composed of invited surgeons with a special interest in surgical meshes, formulated key questions, and forwarded them for processing in subgroups. In January 2016, a workshop was held in Berlin where the findings were presented, discussed, and voted on for consensus. Findings were set out in writing by the subgroups followed by consensus being reached. For the review, 114 studies and background analyses were used. The cumulative data regarding biologic mesh under contaminated conditions do not support the claim that it is better than synthetic mesh. Biologic mesh use should be avoided when bridging is needed. In inguinal hernia repair biologic and biosynthetic meshes do not have a clear advantage over the synthetic meshes. For prevention of incisional or parastomal hernias, there is no evidence to support the use of biologic/biosynthetic meshes. In complex abdominal wall hernia repairs (incarcerated hernia, parastomal hernia, infected mesh, open abdomen, enterocutaneous fistula, and component separation technique), biologic and biosynthetic meshes do not provide a superior alternative to synthetic meshes. The routine use of biologic and biosynthetic meshes cannot be recommended.

Toward An Unstructured Mesh Database

NASA Astrophysics Data System (ADS)

Rezaei Mahdiraji, Alireza; Baumann, Peter Peter

2014-05-01

Unstructured meshes are used in several application domains such as earth sciences (e.g., seismology), medicine, oceanography, cli- mate modeling, GIS as approximate representations of physical objects. Meshes subdivide a domain into smaller geometric elements (called cells) which are glued together by incidence relationships. The subdivision of a domain allows computational manipulation of complicated physical structures. For instance, seismologists model earthquakes using elastic wave propagation solvers on hexahedral meshes. The hexahedral con- tains several hundred millions of grid points and millions of hexahedral cells. Each vertex node in the hexahedrals stores a multitude of data fields. To run simulation on such meshes, one needs to iterate over all the cells, iterate over incident cells to a given cell, retrieve coordinates of cells, assign data values to cells, etc. Although meshes are used in many application domains, to the best of our knowledge there is no database vendor that support unstructured mesh features. Currently, the main tool for querying and manipulating unstructured meshes are mesh libraries, e.g., CGAL and GRAL. Mesh li- braries are dedicated libraries which includes mesh algorithms and can be run on mesh representations. The libraries do not scale with dataset size, do not have declarative query language, and need deep C++ knowledge for query implementations. Furthermore, due to high coupling between the implementations and input file structure, the implementations are less reusable and costly to maintain. A dedicated mesh database offers the following advantages: 1) declarative querying, 2) ease of maintenance, 3) hiding mesh storage structure from applications, and 4) transparent query optimization. To design a mesh database, the first challenge is to define a suitable generic data model for unstructured meshes. We proposed ImG-Complexes data model as a generic topological mesh data model which extends incidence graph model to multi-incidence relationships. We instrument ImG model with sets of optional and application-specific constraints which can be used to check validity of meshes for a specific class of object such as manifold, pseudo-manifold, and simplicial manifold. We conducted experiments to measure the performance of the graph database solution in processing mesh queries and compare it with GrAL mesh library and PostgreSQL database on synthetic and real mesh datasets. The experiments show that each system perform well on specific types of mesh queries, e.g., graph databases perform well on global path-intensive queries. In the future, we investigate database operations for the ImG model and design a mesh query language.

Preparation and biocompatibility evaluation of polypropylene mesh coated with electrospinning membrane for pelvic defects repair.

PubMed

Lu, Yao; Fu, Shaoju; Zhou, Shuanglin; Chen, Ge; Zhu, Chaoting; Li, Nannan; Ma, Ying

2018-05-01

Composite mesh with different materials composition could compensate for the drawbacks brought by single component mesh. Coating a membrane layer on the surface of macroporous mesh is a common method for preparing composite medical mesh. Electrospinning and dipping methods were introduced to form the two kinds of membrane-coated PP meshes (electro-mesh and dip-mesh); several properties were measured based on subcutaneous implantation model in rat. The results revealed that continuous tissue ingrowth could be observed for electro-mesh only with evidences of strength increase (electro-mesh: 0 week - 13.1 ± 0.88 N, 2 week - 16.87 ± 1.39 N, 4 week - 22.04 ± 2.05 N) and thickness increase (electro-mesh: 0 week - 0.437 ± 0.023 mm, 2 week - 0.488 ± 0.025 mm, 4 week - 0.576 ± 0.028 mm). However, no tissues were observed for dip-mesh in the first 2 weeks, both on macroscopic level and microscopic level, proved by strength data (dip-mesh: 0 week - 13.36 ± 1.06 N, 2 week - 13.4 ± 1.33 N, 4 week - 18.61 ± 1.89 N) and thickness data (dip-mesh: 0 week - 0.439 ± 0.018 mm, 2 week - 0.439 ± 0.019 mm, 4 week - 0.502 ± 0.032 mm). Electro-mesh had larger surface area decrease (10.74 ± 1.22%) than that of dip-mesh (2.78 ± 0.52%). The adhesion level of electro-mesh (medium adhesion) was also higher than that of dip-mesh (mild adhesion). Even if showing differences in several properties, both meshes were similar under histological observation, with the ability to support fresh tissues ingrowth. Considering operation environment, electro-mesh seems more suitable than dip-mesh with a rapid tissue growing, medium adhesion rate for repairing pelvic floor defects. Copyright © 2018 Elsevier Ltd. All rights reserved.

Method of and apparatus for modeling interactions

DOEpatents

Budge, Kent G.

2004-01-13

A method and apparatus for modeling interactions can accurately model tribological and other properties and accommodate topological disruptions. Two portions of a problem space are represented, a first with a Lagrangian mesh and a second with an ALE mesh. The ALE and Lagrangian meshes are constructed so that each node on the surface of the Lagrangian mesh is in a known correspondence with adjacent nodes in the ALE mesh. The interaction can be predicted for a time interval. Material flow within the ALE mesh can accurately model complex interactions such as bifurcation. After prediction, nodes in the ALE mesh in correspondence with nodes on the surface of the Lagrangian mesh can be mapped so that they are once again adjacent to their corresponding Lagrangian mesh nodes. The ALE mesh can then be smoothed to reduce mesh distortion that might reduce the accuracy or efficiency of subsequent prediction steps. The process, from prediction through mapping and smoothing, can be repeated until a terminal condition is reached.

Biocompatibility and tissue integration of a novel shape memory surgical mesh for ventral hernia: In vivo animal studies

PubMed Central

Zimkowski, Michael M.; Rentschler, Mark E.; Schoen, Jonathan A.; Mandava, Nageswara; Shandas, Robin

2014-01-01

Approximately 400,000 ventral hernia repair surgeries are performed each year in the United States. Many of these procedures are performed using laparoscopic minimally invasive techniques and employ the use of surgical mesh. The use of surgical mesh has been shown to reduce recurrence rates compared to standard suture repairs. The placement of surgical mesh in a ventral hernia repair procedure can be challenging, and may even complicate the procedure. Others have attempted to provide commercial solutions to the problems of mesh placement, but these have not been well accepted by the clinical community. In this article, two versions of shape memory polymer (SMP)-modified surgical mesh, and unmodified surgical mesh, were compared by performing laparoscopic manipulation in an acute porcine model. Also, SMP-integrated polyester surgical meshes were implanted in four rats for 30–33 days to evaluate chronic biocompatibility and capacity for tissue integration. Porcine results show that the modified mesh provides a controlled, temperature-activated, automated deployment when compared to an unmodified mesh. In rats, results indicate that implanted SMP-modified meshes exhibit exceptional biocompatibility and excellent integration with surrounding tissue with no noticeable differences from the unmodified counterpart. This article provides further evidence that an SMP-modified surgical mesh promises reduction in surgical placement time and that such a mesh is not substantially different from unmodified meshes in chronic biocompatibility. PMID:24327401

The effect of fabric structure on the mechanical properties of warp knitted surgical mesh for hernia repair.

PubMed

Mirjavan, Mohammad; Asayesh, Azita; Asgharian Jeddi, Ali Asghar

2017-02-01

Surgical mesh is being used for healing hernia, pelvic organ prolapse, skull injuries and urinary incontinence. In this research the effect of fabric structure on the mechanical properties of warp knitted surgical meshes in comparison to abdominal fascia has been investigated. For this purpose, warp knitted surgical mesh with five different structures (Tricot, Pin-hole-net, quasi-Sandfly, Sandfly and quasi-Marquissite) were produced using polypropylene monofilament. Thereafter, their mechanical properties such as uniaxial tensile behavior in various directions (wale-wise (90°), course-wise (0°) and diagonal (45°)), bending resistance and crease recovery were analyzed. The meshes demonstrated different elastic modulus in various directions, which can be attributed to the pore shape (pore angle) and underlap angle in the structure of mesh. Except Pin-hole-net mesh, other produced meshes exhibited better level of orthotropy in comparison to abdominal fascia. The most flexible mesh in both wale-wise and course-wise directions was quasi-Sandfly and thereafter quasi-Marquissite. Tricot and Pin-hole-net manifested the highest crease recovery in wale-wise and coursewise directions respectively. The most desirable mesh in terms of porosity was quasi-Marquissite mesh. Overall, the quasi-Marquissite mesh was selected as the most suitable surgical mesh considering all advantages and disadvantages of each produced mesh in this study. Copyright © 2016 Elsevier Ltd. All rights reserved.

Highly Symmetric and Congruently Tiled Meshes for Shells and Domes

PubMed Central

Rasheed, Muhibur; Bajaj, Chandrajit

2016-01-01

We describe the generation of all possible shell and dome shapes that can be uniquely meshed (tiled) using a single type of mesh face (tile), and following a single meshing (tiling) rule that governs the mesh (tile) arrangement with maximal vertex, edge and face symmetries. Such tiling arrangements or congruently tiled meshed shapes, are frequently found in chemical forms (fullerenes or Bucky balls, crystals, quasi-crystals, virus nano shells or capsids), and synthetic shapes (cages, sports domes, modern architectural facades). Congruently tiled meshes are both aesthetic and complete, as they support maximal mesh symmetries with minimal complexity and possess simple generation rules. Here, we generate congruent tilings and meshed shape layouts that satisfy these optimality conditions. Further, the congruent meshes are uniquely mappable to an almost regular 3D polyhedron (or its dual polyhedron) and which exhibits face-transitive (and edge-transitive) congruency with at most two types of vertices (each type transitive to the other). The family of all such congruently meshed polyhedra create a new class of meshed shapes, beyond the well-studied regular, semi-regular and quasi-regular classes, and their duals (platonic, Catalan and Johnson). While our new mesh class is infinite, we prove that there exists a unique mesh parametrization, where each member of the class can be represented by two integer lattice variables, and moreover efficiently constructable. PMID:27563368

Sirolimus-coated, poly(L-lactic acid)-modified polypropylene mesh with minimal intra-peritoneal adhesion formation in a rat model.

PubMed

Lu, S; Hu, W; Zhang, Z; Ji, Z; Zhang, T

2018-05-18

This study evaluated the manufacturing method and anti-adhesion properties of a new composite mesh in the rat model, which was made from sirolimus (SRL) grafts on a poly(L-lactic acid) (PLLA)-modified polypropylene (PP) hernia mesh. PLLA was first grafted onto argon-plasma-treated native PP mesh through catalysis of stannous chloride. SRL was grafted onto the surface of PP-PLLA meshes using catalysis of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 4-dimethylaminopyridine (DMAP) in a CH 2 Cl 2 solvent. Sprague-Dawley female rats received either SRL-coated meshes, PP-PLLA meshes, or native PP meshes to repair abdominal wall defects. At different intervals, rats were euthanized by a lethal dose of chloral hydrate and adhesion area and tenacity were evaluated. Sections of the mesh with adjacent tissues were assessed histologically. Attenuated total reflection Fourier transformed infrared (ATR-FTIR) spectroscopy indicated the existence of a C=O group absorption peak (1724.1 cm -1 ), and scanning electron microscope morphological analysis indicated that the surface of the PP mesh was covered with SRL. Compared to the native PP meshes and PP-PLLA meshes, SRL-coated meshes demonstrated the greatest ability to decrease the formation of adhesions (P < 0.05) and inflammation. The SRL-coated composite mesh showed minimal formation of intra-abdominal adhesions in a rat model of abdominal wall defect repair.

SU-E-T-592: OSL Response of Al2O3:C Detectors Exposed to Therapeutic Proton Beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Granville, DA; Flint, DB; Sawakuchi, GO

Purpose: To characterize the response of Al{sub 2}O{sub 3}:C optically stimulated luminescence (OSL) detectors (OSLDs) exposed to therapeutic proton beams of differing beam quality. Methods: We prepared Al{sub 2}O{sub 3}:C OSLDs from the same material as commercially available nanoDot dosimeters (Landauer, Inc). We irradiated the OSLDs in modulated proton beams of varying quality, as defined by the residual range. An absorbed dose to water of 0.2 Gy was delivered to all OSLDs with the residual range values varying from 0.5 to 23.5 cm (average LET in water from ∼0.5 to 2.5 keV/µm). To investigate the beam quality dependence of differentmore » emission bands within the OSL spectrum, we performed OSLD readouts using both continuous-wave stimulation (CW-OSL) and pulsed stimulation (P-OSL) with two sets of optical filters (Hoya U-340 and Kopp 5113). For all readout modes, the relative absorbed dose sensitivity ( S{sub rel}) for each beam quality was calculated using OSLDs irradiated in a 6 MV photon beam as a reference. Results: We found that the relative absorbed dose sensitivity was highly dependent on both readout mode and integration time of the OSL signal. For CW-OSL signals containing only the blue emission band, S{sub rel} was between 0.85 and 0.94 for 1 s readouts and between 0.82 and 0.93 for 10 s readouts. Similarly, for P-OSL readouts containing only the blue emission band S{sub rel} ranged from 0.86 to 0.91, and 0.82 to 0.93 for 1 s and 10 s readouts, respectively. For OSLD signals containing only the UV emission band, S{sub rel} ranged from 1.00 to 1.46, and 0.97 to 1.30 for P-OSL readouts of 1 s and 10 s, respectively. Conclusion: For measurements of absorbed dose using Al{sub 2}O{sub 3}:C OSLDs in therapeutic proton beams, dependence on beam quality was smallest for readout protocols that selected the blue emission band with small integration times. DA Granville received financial support from the Natural Sciences and Engineering Research Council of Canada.« less

Specificity of a protein-protein interface: local dynamics direct substrate recognition of effector caspases.

PubMed

Fuchs, Julian E; von Grafenstein, Susanne; Huber, Roland G; Wallnoefer, Hannes G; Liedl, Klaus R

2014-04-01

Proteases are prototypes of multispecific protein-protein interfaces. Proteases recognize and cleave protein and peptide substrates at a well-defined position in a substrate binding groove and a plethora of experimental techniques provide insights into their substrate recognition. We investigate the caspase family of cysteine proteases playing a key role in programmed cell death and inflammation, turning caspases into interesting drug targets. Specific ligand binding to one particular caspase is difficult to achieve, as substrate specificities of caspase isoforms are highly similar. In an effort to rationalize substrate specificity of two closely related caspases, we investigate the substrate promiscuity of the effector Caspases 3 and 7 by data mining (cleavage entropy) and by molecular dynamics simulations. We find a strong correlation between binding site rigidity and substrate readout for individual caspase subpockets explaining more stringent substrate readout of Caspase 7 via its narrower conformational space. Caspase 3 subpockets S3 and S4 show elevated local flexibility explaining the more unspecific substrate readout of that isoform in comparison to Caspase 7. We show by in silico exchange mutations in the S3 pocket of the proteases that a proline residue in Caspase 7 contributes to the narrowed conformational space of the binding site. These findings explain the substrate specificities of caspases via a mechanism of conformational selection and highlight the crucial importance of binding site local dynamics in substrate recognition of proteases. Proteins 2014; 82:546-555. © 2013 Wiley Periodicals, Inc. Copyright © 2013 The Authors Proteins: Structure, Function, and Bioinformatics Published by Wiley Periodicals, Inc.

Sensory Gain Outperforms Efficient Readout Mechanisms in Predicting Attention-Related Improvements in Behavior

PubMed Central

Ester, Edward F.; Deering, Sean

2014-01-01

Spatial attention has been postulated to facilitate perceptual processing via several different mechanisms. For instance, attention can amplify neural responses in sensory areas (sensory gain), mediate neural variability (noise modulation), or alter the manner in which sensory signals are selectively read out by postsensory decision mechanisms (efficient readout). Even in the context of simple behavioral tasks, it is unclear how well each of these mechanisms can account for the relationship between attention-modulated changes in behavior and neural activity because few studies have systematically mapped changes between stimulus intensity, attentional focus, neural activity, and behavioral performance. Here, we used a combination of psychophysics, event-related potentials (ERPs), and quantitative modeling to explicitly link attention-related changes in perceptual sensitivity with changes in the ERP amplitudes recorded from human observers. Spatial attention led to a multiplicative increase in the amplitude of an early sensory ERP component (the P1, peaking ∼80–130 ms poststimulus) and in the amplitude of the late positive deflection component (peaking ∼230–330 ms poststimulus). A simple model based on signal detection theory demonstrates that these multiplicative gain changes were sufficient to account for attention-related improvements in perceptual sensitivity, without a need to invoke noise modulation. Moreover, combining the observed multiplicative gain with a postsensory readout mechanism resulted in a significantly poorer description of the observed behavioral data. We conclude that, at least in the context of relatively simple visual discrimination tasks, spatial attention modulates perceptual sensitivity primarily by modulating the gain of neural responses during early sensory processing PMID:25274817

Concurrent 3-D sonifications enable the head-up monitoring of two interrelated aircraft navigation instruments.

PubMed

Towers, John; Burgess-Limerick, Robin; Riek, Stephan

2014-12-01

The aim of this study was to enable the head-up monitoring of two interrelated aircraft navigation instruments by developing a 3-D auditory display that encodes this navigation information within two spatially discrete sonifications. Head-up monitoring of aircraft navigation information utilizing 3-D audio displays, particularly involving concurrently presented sonifications, requires additional research. A flight simulator's head-down waypoint bearing and course deviation instrument readouts were conveyed to participants via a 3-D auditory display. Both readouts were separately represented by a colocated pair of continuous sounds, one fixed and the other varying in pitch, which together encoded the instrument value's deviation from the norm. Each sound pair's position in the listening space indicated the left/right parameter of its instrument's readout. Participants' accuracy in navigating a predetermined flight plan was evaluated while performing a head-up task involving the detection of visual flares in the out-of-cockpit scene. The auditory display significantly improved aircraft heading and course deviation accuracy, head-up time, and flare detections. Head tracking did not improve performance by providing participants with the ability to orient potentially conflicting sounds, suggesting that the use of integrated localizing cues was successful. Conclusion: A supplementary 3-D auditory display enabled effective head-up monitoring of interrelated navigation information normally attended to through a head-down display. Pilots operating aircraft, such as helicopters and unmanned aerial vehicles, may benefit from a supplementary auditory display because they navigate in two dimensions while performing head-up, out-of-aircraft, visual tasks.

A High-Speed, Event-Driven, Active Pixel Sensor Readout for Photon-Counting Microchannel Plate Detectors

NASA Technical Reports Server (NTRS)

Kimble, Randy A.; Pain, B.; Norton, T. J.; Haas, P.; Fisher, Richard R. (Technical Monitor)

2001-01-01

Silicon array readouts for microchannel plate intensifiers offer several attractive features. In this class of detector, the electron cloud output of the MCP intensifier is converted to visible light by a phosphor; that light is then fiber-optically coupled to the silicon array. In photon-counting mode, the resulting light splashes on the silicon array are recognized and centroided to fractional pixel accuracy by off-chip electronics. This process can result in very high (MCP-limited) spatial resolution for the readout while operating at a modest MCP gain (desirable for dynamic range and long term stability). The principal limitation of intensified CCD systems of this type is their severely limited local dynamic range, as accurate photon counting is achieved only if there are not overlapping event splashes within the frame time of the device. This problem can be ameliorated somewhat by processing events only in pre-selected windows of interest or by using an addressable charge injection device (CID) for the readout array. We are currently pursuing the development of an intriguing alternative readout concept based on using an event-driven CMOS Active Pixel Sensor. APS technology permits the incorporation of discriminator circuitry within each pixel. When coupled with suitable CMOS logic outside the array area, the discriminator circuitry can be used to trigger the readout of small sub-array windows only when and where an event splash has been detected, completely eliminating the local dynamic range problem, while achieving a high global count rate capability and maintaining high spatial resolution. We elaborate on this concept and present our progress toward implementing an event-driven APS readout.

Surgical meshes coated with mesenchymal stem cells provide an anti-inflammatory environment by a M2 macrophage polarization.

PubMed

Blázquez, Rebeca; Sánchez-Margallo, Francisco Miguel; Álvarez, Verónica; Usón, Alejandra; Casado, Javier G

2016-02-01

Surgical meshes are widely used in clinics to reinforce soft tissue's defects, and to give support to prolapsed organs. However, the implantation of surgical meshes is commonly related with an inflammatory response being difficult to eradicate without removing the mesh. Here we hypothesize that the combined use of surgical meshes and mesenchymal stem cells (MSCs) could be a useful tool to reduce the inflammatory reaction secondary to mesh implantation. In vitro determinations of viability, metabolic activity and immunomodulation assays were performed on MSCs-coated meshes. Magnetic resonance imaging, evaluation by laparoscopic optical system and histology were performed for safety assessment. Finally, flow cytometry and qRT-PCR were used to elucidate the mechanism of action of MSCs-coated meshes. Our results demonstrate the feasibility to obtain MSCs-coated surgical meshes and their cryopreservability to be used as an 'off the shelf' product. These biological meshes fulfill the safety aspects as non-adverse effects were observed when compared to controls. Moreover, both in vitro and in vivo studies demonstrated that, local immunomodulation of implanted meshes is mediated by a macrophage polarization towards an anti-inflammatory phenotype. In conclusion, the combined usage of surgical meshes with MSCs fulfills the safety requirements for a future clinical application, providing an anti-inflammatory environment that could reduce the inflammatory processes commonly observed after surgical mesh implantation. Surgical meshes are medical devices widely used in clinics to resolve hernias and organs' prolapses, among other disorders. However, the implantation of surgical meshes is commonly related with an inflammatory response being difficult to eradicate without removing the mesh, causing pain and discomfort in the patient. Previously, the anti-inflammatory, immunomodulatory and pro-regenerative ability of mesenchymal stem cells (MSCs) have been described. To our knowledge, this is the first report where the anti-inflammatory and pro-regenerative ability of MSCs have been successfully applied in combination with surgical meshes, reducing the inflammatory processes commonly observed after mesh implantation. Moreover, our in vitro and in vivo results highlight the safety and efficacy of these bioactive meshes as a 'ready to use' medical product. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Bone Marrow–Derived Mesenchymal Stem Cells Enhance Bacterial Clearance and Preserve Bioprosthetic Integrity in a Model of Mesh Infection

PubMed Central

Criman, Erik T.; Kurata, Wendy E.; Matsumoto, Karen W.; Aubin, Harry T.; Campbell, Carmen E.

2016-01-01

Background: The reported incidence of mesh infection in contaminated operative fields is as high as 30% regardless of the material used. Recently, mesenchymal stem cells (MSCs) have been shown to possess favorable immunomodulatory properties and improve tissue incorporation when seeded onto bioprosthetics. The aim of this study was to evaluate whether seeding noncrosslinked bovine pericardium (Veritas Collagen Matrix) with allogeneic bone marrow–derived MSCs improves infection resistance in vivo after inoculation with Escherichia coli (E. coli). Methods: Rat bone marrow–derived MSCs at passage 3 were seeded onto bovine pericardium and cultured for 7 days before implantation. Additional rats (n = 24) were implanted subcutaneously with MSC-seeded or unseeded mesh and inoculated with 7 × 105 colony-forming units of E. coli or saline before wound closure (group 1, unseeded mesh/saline; group 2, unseeded mesh/E. coli; group 3, MSC-seeded mesh/E. coli; 8 rats per group). Meshes were explanted at 4 weeks and underwent microbiologic and histologic analyses. Results: MSC-seeded meshes inoculated with E. coli demonstrated superior bacterial clearance and preservation of mesh integrity compared with E. coli–inoculated unseeded meshes (87.5% versus 0% clearance; p = 0.001). Complete mesh degradation concurrent with abscess formation was observed in 100% of rats in the unseeded/E. coli group, which is in contrast to 12.5% of rats in the MSC-seeded/E. coli group. Histologic evaluation determined that remodeling characteristics of E. coli–inoculated MSC-seeded meshes were similar to those of uninfected meshes 4 weeks after implantation. Conclusions: Augmenting a bioprosthetic material with stem cells seems to markedly enhance resistance to bacterial infection in vivo and preserve mesh integrity. PMID:27482490

An adaptive mesh-moving and refinement procedure for one-dimensional conservation laws

NASA Technical Reports Server (NTRS)

Biswas, Rupak; Flaherty, Joseph E.; Arney, David C.

1993-01-01

We examine the performance of an adaptive mesh-moving and /or local mesh refinement procedure for the finite difference solution of one-dimensional hyperbolic systems of conservation laws. Adaptive motion of a base mesh is designed to isolate spatially distinct phenomena, and recursive local refinement of the time step and cells of the stationary or moving base mesh is performed in regions where a refinement indicator exceeds a prescribed tolerance. These adaptive procedures are incorporated into a computer code that includes a MacCormack finite difference scheme wih Davis' artificial viscosity model and a discretization error estimate based on Richardson's extrapolation. Experiments are conducted on three problems in order to qualify the advantages of adaptive techniques relative to uniform mesh computations and the relative benefits of mesh moving and refinement. Key results indicate that local mesh refinement, with and without mesh moving, can provide reliable solutions at much lower computational cost than possible on uniform meshes; that mesh motion can be used to improve the results of uniform mesh solutions for a modest computational effort; that the cost of managing the tree data structure associated with refinement is small; and that a combination of mesh motion and refinement reliably produces solutions for the least cost per unit accuracy.

Introducing a distributed unstructured mesh into gyrokinetic particle-in-cell code, XGC

NASA Astrophysics Data System (ADS)

Yoon, Eisung; Shephard, Mark; Seol, E. Seegyoung; Kalyanaraman, Kaushik

2017-10-01

XGC has shown good scalability for large leadership supercomputers. The current production version uses a copy of the entire unstructured finite element mesh on every MPI rank. Although an obvious scalability issue if the mesh sizes are to be dramatically increased, the current approach is also not optimal with respect to data locality of particles and mesh information. To address these issues we have initiated the development of a distributed mesh PIC method. This approach directly addresses the base scalability issue with respect to mesh size and, through the use of a mesh entity centric view of the particle mesh relationship, provides opportunities to address data locality needs of many core and GPU supported heterogeneous systems. The parallel mesh PIC capabilities are being built on the Parallel Unstructured Mesh Infrastructure (PUMI). The presentation will first overview the form of mesh distribution used and indicate the structures and functions used to support the mesh, the particles and their interaction. Attention will then focus on the node-level optimizations being carried out to ensure performant operation of all PIC operations on the distributed mesh. Partnership for Edge Physics Simulation (EPSI) Grant No. DE-SC0008449 and Center for Extended Magnetohydrodynamic Modeling (CEMM) Grant No. DE-SC0006618.

The PAUCam readout electronics system

NASA Astrophysics Data System (ADS)

Jiménez, Jorge; Illa, José M.; Cardiel-Sas, Laia; de Vicente, Juan; Castilla, Javier; Casas, Ricard

2016-08-01

The PAUCam is an optical camera with a wide field of view of 1 deg x 1 deg and up to 46 narrow and broad band filters. The camera is already installed on the William Herschel Telescope (WHT) in the Canary Islands, Spain and successfully commissioned during the first period of 2015. The paper presents the main results from the readout electronics commissioning tests and include an overview of the whole readout electronics system, its configuration and current performance.

The Philosophy and Feasibility of Dual Readout Calorimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hauptman, John

2006-10-27

I will discuss the general physical ideas behind dual-readout calorimetry, their implementation in DREAM (Dual REAdout Module) with exact separation of scintillation and Cerenkov light, implementation with mixed light in DREAM fibers, anticipated implementation in PbWO4 crystals with applications to the 4th Concept detector and to CMS, use in high energy gamma-ray and cosmic ray astrophysics with Cerenkov and N2 fluorescent light, and implementation in the 4th Concept detector for muon identification.

Readout and DAQ for Pixel Detectors

NASA Astrophysics Data System (ADS)

Platkevic, Michal

2010-01-01

Data readout and acquisition control of pixel detectors demand the transfer of significantly a large amounts of bits between the detector and the computer. For this purpose dedicated interfaces are used which are designed with focus on features like speed, small dimensions or flexibility of use such as digital signal processors, field-programmable gate arrays (FPGA) and USB communication ports. This work summarizes the readout and DAQ system built for state-of-the-art pixel detectors of the Medipix family.

Hyper Suprime-Cam: development of the CCD readout electronics

NASA Astrophysics Data System (ADS)

Nakaya, Hidehiko; Uchida, Tomohisa; Miyatake, Hironao; Fujimori, Hiroki; Mineo, Sogo; Aihara, Hiroaki; Furusawa, Hisanori; Kamata, Yukiko; Karoji, Hiroshi; Kawanomoto, Satoshi; Komiyama, Yutaka; Miyazaki, Satoshi; Morokuma, Tomoki; Obuchi, Yoshiyuki; Okura, Yuki; Tanaka, Manobu; Tanaka, Yoko; Uraguchi, Fumihiro; Utsumi, Yosuke

2010-07-01

Hyper Suprime-Cam (HSC) employs 116 of 2k×4k CCDs with 464 signal outputs in total. The image size exceeds 2 GBytes, and the data can be readout every 10 seconds which results in the data rate of 210 Mbytes / sec. The data is digitized to 16-bit. The readout noise of the electronics at the readout time of 20 seconds is ~0.9 ADU, and the one with CCD is ~1.5 ADU which corresponds to ~4.5 e. The linearity error fits within +/- 0.5 % up to 150,000 e. The CCD readout electronics for HSC was newly developed based on the electronics for Suprime-Cam. The frontend electronics (FEE) is placed in the vacuum dewar, and the backend electronics (BEE) is mounted on the outside of the dewar on the prime focus unit. The FEE boards were designed to minimize the outgas and to maximize the heat transfer efficiency to keep the vacuum of the dewar. The BEE boards were designed to be simple and small as long as to achieve the readout time within 10 seconds. The production of the system has been finished, and the full set of the boards are being tested with several CCDs installed in the HSC dewar. We will show the system design, performance, and the current status of the development.

CMOS SiPM with integrated amplifier

NASA Astrophysics Data System (ADS)

Schwinger, Alexander; Brockherde, Werner; Hosticka, Bedrich J.; Vogt, Holger

2017-02-01

The integration of silicon photomultiplier (SiPM) and frontend electronics in a suitable optoelectronic CMOS process is a promising approach to increase the versatility of single-photon avalanche diode (SPAD)-based singlephoton detectors. By integrating readout amplifiers, the device output capacitance can be reduced to minimize the waveform tail, which is especially important for large area detectors (>10 × 10mm2). Possible architectures include a single readout amplifier for the whole detector, which reduces the output capacitance to 1:1 pF at minimal reduction in detector active area. On the other hand, including a readout amplifier in every SiPM cell would greatly improve the total output capacitance by minimizing the influence of metal routing parasitic capacitance, but requiring a prohibitive amount of detector area. As tradeoff, the proposed detector features one readout amplifier for each column of the detector matrix to allow for a moderate reduction in output capacitance while allowing the electronics to be placed in the periphery of the active detector area. The presented detector with a total size of 1.7 ♢ 1.0mm2 features 400 cells with a 50 μm pitch, where the signal of each column of 20 SiPM cells is summed in a readout channel. The 20 readout channels are subsequently summed into one output channel, to allow the device to be used as a drop-in replacement for commonly used analog SiPMs.

Single-Shot Charge Readout Using a Cryogenic Heterojunction Bipolar Transistor Preamplifier Inline with a Silicon Single Electron Transistor at Millikelvin Temperatures

NASA Astrophysics Data System (ADS)

Curry, Matthew; England, Troy; Wendt, Joel; Pluym, Tammy; Lilly, Michael; Carr, Stephen; Carroll, Malcolm

Single-shot readout is a requirement for many implementations of quantum information processing. The single-shot readout fidelity is dependent on the signal-to-noise-ratio (SNR) and bandwidth of the readout detection technique. Several different approaches are being pursued to enhance read-out including RF-reflectometry, RF-transmission, parametric amplification, and transistor-based cryogenic preamplification. The transistor-based cryogenic preamplifier is attractive in part because of the reduced experimental complexity compared with the RF techniques. Here we present single-shot charge readout using a cryogenic Heterojunction-Bipolar-Transistor (HBT) inline with a silicon SET charge-sensor at millikelvin temperatures. For the relevant range of HBT DC-biasing, the current gain is 100 to 2000 and the power dissipation is 50 nW to 5 μW, with the microfabricated SET and discrete HBT in an integrated package mounted to the mixing chamber stage of a dilution refrigerator. We experimentally demonstrate a SNR of up to 10 with a bandwidth of 1 MHz, corresponding to a single-shot time-domain charge-sensitivity of approximately 10-4 e / √Hz. This measured charge-sensitivity is comparable to the values reported using the RF techniques. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

Hexahedral Mesh Untangling

DOE Office of Scientific and Technical Information (OSTI.GOV)

KNUPP,PATRICK

2000-12-13

We investigate a well-motivated mesh untangling objective function whose optimization automatically produces non-inverted elements when possible. Examples show the procedure is highly effective on simplicial meshes and on non-simplicial (e.g., hexahedral) meshes constructed via mapping or sweeping algorithms. The current whisker-weaving (WW) algorithm in CUBIT usually produces hexahedral meshes that are unsuitable for analyses due to inverted elements. The majority of these meshes cannot be untangled using the new objective function. The most likely source of the difficulty is poor mesh topology.

Method of modifying a volume mesh using sheet extraction

DOEpatents

Borden, Michael J [Albuquerque, NM; Shepherd, Jason F [Albuquerque, NM

2007-02-20

A method and machine-readable medium provide a technique to modify a hexahedral finite element volume mesh using dual generation and sheet extraction. After generating a dual of a volume stack (mesh), a predetermined algorithm may be followed to modify the volume mesh of hexahedral elements. The predetermined algorithm may include the steps of determining a sheet of hexahedral mesh elements, generating nodes for merging, and merging the nodes to delete the sheet of hexahedral mesh elements and modify the volume mesh.

Investigation of different simulation approaches on a high-head Francis turbine and comparison with model test data: Francis-99

NASA Astrophysics Data System (ADS)

Mössinger, Peter; Jester-Zürker, Roland; Jung, Alexander

2015-01-01

Numerical investigations of hydraulic turbo machines under steady-state conditions are state of the art in current product development processes. Nevertheless allow increasing computational resources refined discretization methods, more sophisticated turbulence models and therefore better predictions of results as well as the quantification of existing uncertainties. Single stage investigations are done using in-house tools for meshing and set-up procedure. Beside different model domains and a mesh study to reduce mesh dependencies, the variation of several eddy viscosity and Reynolds stress turbulence models are investigated. All obtained results are compared with available model test data. In addition to global values, measured magnitudes in the vaneless space, at runner blade and draft tube positions in term of pressure and velocity are considered. From there it is possible to estimate the influence and relevance of various model domains depending on different operating points and numerical variations. Good agreement can be found for pressure and velocity measurements with all model configurations and, except the BSL-RSM model, all turbulence models. At part load, deviations in hydraulic efficiency are at a large magnitude, whereas at best efficiency and high load operating point efficiencies are close to the measurement. A consideration of the runner side gap geometry as well as a refined mesh is able to improve the results either in relation to hydraulic efficiency or velocity distribution with the drawbacks of less stable numerics and increasing computational time.

New approaches to virtual environment surgery

NASA Technical Reports Server (NTRS)

Ross, M. D.; Twombly, A.; Lee, A. W.; Cheng, R.; Senger, S.

1999-01-01

This research focused on two main problems: 1) low cost, high fidelity stereoscopic imaging of complex tissues and organs; and 2) virtual cutting of tissue. A further objective was to develop these images and virtual tissue cutting methods for use in a telemedicine project that would connect remote sites using the Next Generation Internet. For goal one we used a CT scan of a human heart, a desktop PC with an OpenGL graphics accelerator card, and LCD stereoscopic glasses. Use of multiresolution meshes ranging from approximately 1,000,000 to 20,000 polygons speeded interactive rendering rates enormously while retaining general topography of the dataset. For goal two, we used a CT scan of an infant skull with premature closure of the right coronal suture, a Silicon Graphics Onyx workstation, a Fakespace Immersive WorkBench and CrystalEyes LCD glasses. The high fidelity mesh of the skull was reduced from one million to 50,000 polygons. The cut path was automatically calculated as the shortest distance along the mesh between a small number of hand selected vertices. The region outlined by the cut path was then separated from the skull and translated/rotated to assume a new position. The results indicate that widespread high fidelity imaging in virtual environment is possible using ordinary PC capabilities if appropriate mesh reduction methods are employed. The software cutting tool is applicable to heart and other organs for surgery planning, for training surgeons in a virtual environment, and for telemedicine purposes.

Chi-square-based scoring function for categorization of MEDLINE citations.

PubMed

Kastrin, A; Peterlin, B; Hristovski, D

2010-01-01

Text categorization has been used in biomedical informatics for identifying documents containing relevant topics of interest. We developed a simple method that uses a chi-square-based scoring function to determine the likelihood of MEDLINE citations containing genetic relevant topic. Our procedure requires construction of a genetic and a nongenetic domain document corpus. We used MeSH descriptors assigned to MEDLINE citations for this categorization task. We compared frequencies of MeSH descriptors between two corpora applying chi-square test. A MeSH descriptor was considered to be a positive indicator if its relative observed frequency in the genetic domain corpus was greater than its relative observed frequency in the nongenetic domain corpus. The output of the proposed method is a list of scores for all the citations, with the highest score given to those citations containing MeSH descriptors typical for the genetic domain. Validation was done on a set of 734 manually annotated MEDLINE citations. It achieved predictive accuracy of 0.87 with 0.69 recall and 0.64 precision. We evaluated the method by comparing it to three machine-learning algorithms (support vector machines, decision trees, naïve Bayes). Although the differences were not statistically significantly different, results showed that our chi-square scoring performs as good as compared machine-learning algorithms. We suggest that the chi-square scoring is an effective solution to help categorize MEDLINE citations. The algorithm is implemented in the BITOLA literature-based discovery support system as a preprocessor for gene symbol disambiguation process.

A general gridding, discretization, and coarsening methodology for modeling flow in porous formations with discrete geological features

NASA Astrophysics Data System (ADS)

Karimi-Fard, M.; Durlofsky, L. J.

2016-10-01

A comprehensive framework for modeling flow in porous media containing thin, discrete features, which could be high-permeability fractures or low-permeability deformation bands, is presented. The key steps of the methodology are mesh generation, fine-grid discretization, upscaling, and coarse-grid discretization. Our specialized gridding technique combines a set of intersecting triangulated surfaces by constructing approximate intersections using existing edges. This procedure creates a conforming mesh of all surfaces, which defines the internal boundaries for the volumetric mesh. The flow equations are discretized on this conforming fine mesh using an optimized two-point flux finite-volume approximation. The resulting discrete model is represented by a list of control-volumes with associated positions and pore-volumes, and a list of cell-to-cell connections with associated transmissibilities. Coarse models are then constructed by the aggregation of fine-grid cells, and the transmissibilities between adjacent coarse cells are obtained using flow-based upscaling procedures. Through appropriate computation of fracture-matrix transmissibilities, a dual-continuum representation is obtained on the coarse scale in regions with connected fracture networks. The fine and coarse discrete models generated within the framework are compatible with any connectivity-based simulator. The applicability of the methodology is illustrated for several two- and three-dimensional examples. In particular, we consider gas production from naturally fractured low-permeability formations, and transport through complex fracture networks. In all cases, highly accurate solutions are obtained with significant model reduction.

Noise and spectroscopic performance of DEPMOSFET matrix devices for XEUS

NASA Astrophysics Data System (ADS)

Treis, J.; Fischer, P.; Hälker, O.; Herrmann, S.; Kohrs, R.; Krüger, H.; Lechner, P.; Lutz, G.; Peric, I.; Porro, M.; Richter, R. H.; Strüder, L.; Trimpl, M.; Wermes, N.; Wölfel, S.

2005-08-01

DEPMOSFET based Active Pixel Sensor (APS) matrix devices, originally developed to cope with the challenging requirements of the XEUS Wide Field Imager, have proven to be a promising new imager concept for a variety of future X-ray imaging and spectroscopy missions like Simbol-X. The devices combine excellent energy resolution, high speed readout and low power consumption with the attractive feature of random accessibility of pixels. A production of sensor prototypes with 64 x 64 pixels with a size of 75 μm x 75 μm each has recently been finished at the MPI semiconductor laboratory in Munich. The devices are built for row-wise readout and require dedicated control and signal processing electronics of the CAMEX type, which is integrated together with the sensor onto a readout hybrid. A number of hybrids incorporating the most promising sensor design variants has been built, and their performance has been studied in detail. A spectroscopic resolution of 131 eV has been measured, the readout noise is as low as 3.5 e- ENC. Here, the dependence of readout noise and spectroscopic resolution on the device temperature is presented.

Alternative Post-Processing on a CMOS Chip to Fabricate a Planar Microelectrode Array

PubMed Central

López-Huerta, Francisco; Herrera-May, Agustín L.; Estrada-López, Johan J.; Zuñiga-Islas, Carlos; Cervantes-Sanchez, Blanca; Soto, Enrique; Soto-Cruz, Blanca S.

2011-01-01

We present an alternative post-processing on a CMOS chip to release a planar microelectrode array (pMEA) integrated with its signal readout circuit, which can be used for monitoring the neuronal activity of vestibular ganglion neurons in newborn Wistar strain rats. This chip is fabricated through a 0.6 μm CMOS standard process and it has 12 pMEA through a 4 × 3 electrodes matrix. The alternative CMOS post-process includes the development of masks to protect the readout circuit and the power supply pads. A wet etching process eliminates the aluminum located on the surface of the p+-type silicon. This silicon is used as transducer for recording the neuronal activity and as interface between the readout circuit and neurons. The readout circuit is composed of an amplifier and tunable bandpass filter, which is placed on a 0.015 mm2 silicon area. The tunable bandpass filter has a bandwidth of 98 kHz and a common mode rejection ratio (CMRR) of 87 dB. These characteristics of the readout circuit are appropriate for neuronal recording applications. PMID:22346681

Fast Readout Architectures for Large Arrays of Digital Pixels: Examples and Applications

PubMed Central

Gabrielli, A.

2014-01-01

Modern pixel detectors, particularly those designed and constructed for applications and experiments for high-energy physics, are commonly built implementing general readout architectures, not specifically optimized in terms of speed. High-energy physics experiments use bidimensional matrices of sensitive elements located on a silicon die. Sensors are read out via other integrated circuits bump bonded over the sensor dies. The speed of the readout electronics can significantly increase the overall performance of the system, and so here novel forms of readout architectures are studied and described. These circuits have been investigated in terms of speed and are particularly suited for large monolithic, low-pitch pixel detectors. The idea is to have a small simple structure that may be expanded to fit large matrices without affecting the layout complexity of the chip, while maintaining a reasonably high readout speed. The solutions might be applied to devices for applications not only in physics but also to general-purpose pixel detectors whenever online fast data sparsification is required. The paper presents also simulations on the efficiencies of the systems as proof of concept for the proposed ideas. PMID:24778588

Development of readout electronics for POLARBEAR-2 cosmic microwave background experiment

DOE PAGES

Hattori, K.; Akiba, Y.; Arnold, K.; ...

2016-01-06

The readout of transition-edge sensor (TES) bolometers with a large multiplexing factor is key for the next generation cosmic microwave background (CMB) experiment, Polarbear-2, having 7588 TES bolometers. To enable the large arrays, we have been developing a readout system with a multiplexing factor of 40 in the frequency domain. Extending that architecture to 40 bolometers requires an increase in the bandwidth of the SQUID electronics, above 4 MHz. This paper focuses on cryogenic readout and shows how it affects cross talk and the responsivity of the TES bolometers. A series resistance, such as equivalent series resistance of capacitors formore » LC filters, leads to non-linear response of the bolometers. A wiring inductance modulates a voltage across the bolometers and causes cross talk. They should be controlled well to reduce systematic errors in CMB observations. As a result, we have been developing a cryogenic readout with a low series impedance and have tuned bolometers in the middle of their transition at a high frequency (>3 MHz).« less

Alternative post-processing on a CMOS chip to fabricate a planar microelectrode array.

PubMed

López-Huerta, Francisco; Herrera-May, Agustín L; Estrada-López, Johan J; Zuñiga-Islas, Carlos; Cervantes-Sanchez, Blanca; Soto, Enrique; Soto-Cruz, Blanca S

2011-01-01

We present an alternative post-processing on a CMOS chip to release a planar microelectrode array (pMEA) integrated with its signal readout circuit, which can be used for monitoring the neuronal activity of vestibular ganglion neurons in newborn Wistar strain rats. This chip is fabricated through a 0.6 μm CMOS standard process and it has 12 pMEA through a 4 × 3 electrodes matrix. The alternative CMOS post-process includes the development of masks to protect the readout circuit and the power supply pads. A wet etching process eliminates the aluminum located on the surface of the p+ -type silicon. This silicon is used as transducer for recording the neuronal activity and as interface between the readout circuit and neurons. The readout circuit is composed of an amplifier and tunable bandpass filter, which is placed on a 0.015 mm2 silicon area. The tunable bandpass filter has a bandwidth of 98 kHz and a common mode rejection ratio (CMRR) of 87 dB. These characteristics of the readout circuit are appropriate for neuronal recording applications.

The Phase-2 electronics upgrade of the ATLAS liquid argon calorimeter system

NASA Astrophysics Data System (ADS)

Vachon, B.

2018-03-01

The LHC high-luminosity upgrade in 2024-2026 requires the associated detectors to operate at luminosities about 5-7 times larger than assumed in their original design. The pile-up is expected to increase to up to 200 events per proton bunch-crossing. The current readout of the ATLAS liquid argon calorimeters does not provide sufficient buffering and bandwidth capabilities to accommodate the hardware triggers requirements imposed by these harsh conditions. Furthermore, the expected total radiation doses are beyond the qualification range of the current front-end electronics. For these reasons an almost complete replacement of the front-end and off-detector readout system is foreseen for the 182,468 readout channels. The new readout system will be based on a free-running architecture, where calorimeter signals are amplified, shaped and digitized by on-detector electronics, then sent at 40 MHz to the off-detector electronics for further processing. Results from the design studies on the performance of the components of the readout system are presented, as well as the results of the tests of the first prototypes.

Room temperature 1040fps, 1 megapixel photon-counting image sensor with 1.1um pixel pitch

NASA Astrophysics Data System (ADS)

Masoodian, S.; Ma, J.; Starkey, D.; Wang, T. J.; Yamashita, Y.; Fossum, E. R.

2017-05-01

A 1Mjot single-bit quanta image sensor (QIS) implemented in a stacked backside-illuminated (BSI) process is presented. This is the first work to report a megapixel photon-counting CMOS-type image sensor to the best of our knowledge. A QIS with 1.1μm pitch tapered-pump-gate jots is implemented with cluster-parallel readout, where each cluster of jots is associated with its own dedicated readout electronics stacked under the cluster. Power dissipation is reduced with this cluster readout because of the reduced column bus parasitic capacitance, which is important for the development of 1Gjot arrays. The QIS functions at 1040fps with binary readout and dissipates only 17.6mW, including I/O pads. The readout signal chain uses a fully differential charge-transfer amplifier (CTA) gain stage before a 1b-ADC to achieve an energy/bit FOM of 16.1pJ/b and 6.9pJ/b for the whole sensor and gain stage+ADC, respectively. Analog outputs with on-chip gain are implemented for pixel characterization purposes.

Enabling Large Focal Plane Arrays Through Mosaic Hybridization

NASA Technical Reports Server (NTRS)

Miller, Timothy M.; Jhabvala, Christine A.; Leong, Edward; Costen, Nick P.; Sharp, Elmer; Adachi, Tomoko; Benford, Dominic J.

2012-01-01

We have demonstrated advances in mosaic hybridization that will enable very large format far-infrared detectors. Specifically we have produced electrical detector models via mosaic hybridization yielding superconducting circuit patbs by hybridizing separately fabricated sub-units onto a single detector unit. The detector model was made on a 100mm diameter wafer while four model readout quadrant chips were made from a separate 100mm wafer. The individually fabric.ted parts were hybridized using a Suss FCI50 flip chip bonder to assemble the detector-readout stack. Once all of the hybridized readouts were in place, a single, large and thick silicon substrate was placed on the stack and attached with permanent epoxy to provide strength and a Coefficient of Thermal Expansion match to the silicon components underneath. Wirebond pads on the readout chips connect circuits to warm readout electronics; and were used to validate the successful superconducting electrical interconnection of the model mosaic-hybrid detector. This demonstration is directly scalable to 150 mm diameter wafers, enabling pixel areas over ten times the area currently available.

Comparison of the fracture resistances of glass fiber mesh- and metal mesh-reinforced maxillary complete denture under dynamic fatigue loading.

PubMed

Im, So-Min; Huh, Yoon-Hyuk; Cho, Lee-Ra; Park, Chan-Jin

2017-02-01

The aim of this study was to investigate the effect of reinforcing materials on the fracture resistances of glass fiber mesh- and Cr-Co metal mesh-reinforced maxillary complete dentures under fatigue loading. Glass fiber mesh- and Cr-Co mesh-reinforced maxillary complete dentures were fabricated using silicone molds and acrylic resin. A control group was prepared with no reinforcement (n = 15 per group). After fatigue loading was applied using a chewing simulator, fracture resistance was measured by a universal testing machine. The fracture patterns were analyzed and the fractured surfaces were observed by scanning electron microscopy. After cyclic loading, none of the dentures showed cracks or fractures. During fracture resistance testing, all unreinforced dentures experienced complete fracture. The mesh-reinforced dentures primarily showed posterior framework fracture. Deformation of the all-metal framework caused the metal mesh-reinforced denture to exhibit the highest fracture resistance, followed by the glass fiber mesh-reinforced denture ( P <.05) and the control group ( P <.05). The glass fiber mesh-reinforced denture primarily maintained its original shape with unbroken fibers. River line pattern of the control group, dimples and interdendritic fractures of the metal mesh group, and radial fracture lines of the glass fiber group were observed on the fractured surfaces. The glass fiber mesh-reinforced denture exhibits a fracture resistance higher than that of the unreinforced denture, but lower than that of the metal mesh-reinforced denture because of the deformation of the metal mesh. The glass fiber mesh-reinforced denture maintains its shape even after fracture, indicating the possibility of easier repair.

Transparent ceramic garnet scintillator optimization via composition and co-doping for high-energy resolution gamma spectrometers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Cherepy, Nerine J.; Payne, Stephen A.; Seeley, Zachary M.; Beck, Patrick R.; Swanberg, Erik L.; Hunter, Steven L.

2016-09-01

Breakthrough energy resolution, R(662keV) <4%, has been achieved with an oxide scintillator, Cerium-doped Gadolinium Yttrium Gallium Aluminum Garnet, or GYGAG(Ce), by optimizing fabrication conditions. Here we describe the dependence of scintillation light yield and energy resolution on several variables: (1) Stoichiometry, in particular Gd/Y and Ga/Al ratios which modify the bandgap energy, (2) Processing methods, including vacuum vs. oxygen sintering, and (3) Trace co-dopants that influence the formation of Ce4+ and modify the intra-bandgap trap distribution. To learn about how chemical composition influences the scintillation properties of transparent ceramic garnet scintillators, we have measured: scintillation decay component amplitudes; intensity and duration of afterglow; thermoluminescence glow curve peak positions and amplitudes; integrated light yield; light yield non-proportionality, as measured in the Scintillator Light Yield Non-Proportionality Characterization Instrument (SLYNCI); and energy resolution for gamma spectroscopy. Optimized GYGAG(Ce) provides R(662 keV) =3.0%, for 0.05 cm3 size ceramics with Silicon photodiode readout, and R(662 keV) =4.6%, at 2 in3 size with PMT readout.

NaNet3: The on-shore readout and slow-control board for the KM3NeT-Italia underwater neutrino telescope

NASA Astrophysics Data System (ADS)

Ammendola, R.; Biagioni, A.; Frezza, O.; Lo Cicero, F.; Martinelli, M.; Paolucci, P. S.; Pontisso, L.; Simula, F.; Vicini, P.; Ameli, F.; Nicolau, C. A.; Pastorelli, E.; Simeone, F.; Tosoratto, L.; Lonardo, A.

2016-04-01

The KM3NeT-Italia underwater neutrino detection unit, the tower, consists of 14 floors. Each floor supports 6 Optical Modules containing front-end electronics needed to digitize the PMT signal, format and transmit the data and 2 hydrophones that reconstruct in real-time the position of Optical Modules, for a maximum tower throughput of more than 600 MB/s. All floor data are collected by the Floor Control Module (FCM) board and transmitted by optical bidirectional virtual point-to-point connections to the on-shore laboratory, each FCM needing an on-shore counterpart as communication endpoint. In this contribution we present NaNet3, an on-shore readout board based on Altera Stratix V GX FPGA able to manage multiple FCM data channels with a capability of 800 Mbps each. The design is a NaNet customization for the KM3NeT-Italia experiment, adding support in its I/O interface for a synchronous link protocol with deterministic latency at physical level and for a Time Division Multiplexing protocol at data level.

Method of modifying a volume mesh using sheet insertion

DOEpatents

Borden, Michael J [Albuquerque, NM; Shepherd, Jason F [Albuquerque, NM

2006-08-29

A method and machine-readable medium provide a technique to modify a hexahedral finite element volume mesh using dual generation and sheet insertion. After generating a dual of a volume stack (mesh), a predetermined algorithm may be followed to modify (refine) the volume mesh of hexahedral elements. The predetermined algorithm may include the steps of locating a sheet of hexahedral mesh elements, determining a plurality of hexahedral elements within the sheet to refine, shrinking the plurality of elements, and inserting a new sheet of hexahedral elements adjacently to modify the volume mesh. Additionally, another predetermined algorithm using mesh cutting may be followed to modify a volume mesh.

Predicting mesh density for adaptive modelling of the global atmosphere.

PubMed

Weller, Hilary

2009-11-28

The shallow water equations are solved using a mesh of polygons on the sphere, which adapts infrequently to the predicted future solution. Infrequent mesh adaptation reduces the cost of adaptation and load-balancing and will thus allow for more accurate mapping on adaptation. We simulate the growth of a barotropically unstable jet adapting the mesh every 12 h. Using an adaptation criterion based largely on the gradient of the vorticity leads to a mesh with around 20 per cent of the cells of a uniform mesh that gives equivalent results. This is a similar proportion to previous studies of the same test case with mesh adaptation every 1-20 min. The prediction of the mesh density involves solving the shallow water equations on a coarse mesh in advance of the locally refined mesh in order to estimate where features requiring higher resolution will grow, decay or move to. The adaptation criterion consists of two parts: that resolved on the coarse mesh, and that which is not resolved and so is passively advected on the coarse mesh. This combination leads to a balance between resolving features controlled by the large-scale dynamics and maintaining fine-scale features.

MeSH Now: automatic MeSH indexing at PubMed scale via learning to rank.

PubMed

Mao, Yuqing; Lu, Zhiyong

2017-04-17

MeSH indexing is the task of assigning relevant MeSH terms based on a manual reading of scholarly publications by human indexers. The task is highly important for improving literature retrieval and many other scientific investigations in biomedical research. Unfortunately, given its manual nature, the process of MeSH indexing is both time-consuming (new articles are not immediately indexed until 2 or 3 months later) and costly (approximately ten dollars per article). In response, automatic indexing by computers has been previously proposed and attempted but remains challenging. In order to advance the state of the art in automatic MeSH indexing, a community-wide shared task called BioASQ was recently organized. We propose MeSH Now, an integrated approach that first uses multiple strategies to generate a combined list of candidate MeSH terms for a target article. Through a novel learning-to-rank framework, MeSH Now then ranks the list of candidate terms based on their relevance to the target article. Finally, MeSH Now selects the highest-ranked MeSH terms via a post-processing module. We assessed MeSH Now on two separate benchmarking datasets using traditional precision, recall and F 1 -score metrics. In both evaluations, MeSH Now consistently achieved over 0.60 in F-score, ranging from 0.610 to 0.612. Furthermore, additional experiments show that MeSH Now can be optimized by parallel computing in order to process MEDLINE documents on a large scale. We conclude that MeSH Now is a robust approach with state-of-the-art performance for automatic MeSH indexing and that MeSH Now is capable of processing PubMed scale documents within a reasonable time frame. http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/Demo/MeSHNow/ .

Indium phosphide-based monolithically integrated PIN waveguide photodiode readout for resonant cantilever sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siwak, N. P.; Laboratory for the Physical Sciences, 8050 Greenmead Drive, College Park, Maryland 20740; Fan, X. Z.

2014-10-06

An integrated photodiode displacement readout scheme for a microelectromechanical cantilever waveguide resonator sensing platform is presented. III-V semiconductors are used to enable the monolithic integration of passive waveguides with active optical components. This work builds upon previously demonstrated results by measuring the displacement of cantilever waveguide resonators with on-chip waveguide PIN photodiodes. The on-chip integration of the readout provides an additional 70% improvement in mass sensitivity compared to off-chip photodetector designs due to measurement stability and minimized coupling loss. In addition to increased measurement stability, reduced packaging complexity is achieved due to the simplicity of the readout design. We havemore » fabricated cantilever waveguides with integrated photodetectors and experimentally characterized these cantilever sensors with monolithically integrated PIN photodiodes.« less

Performance of 20:1 multiplexer for large area charge readouts in directional dark matter TPC detectors

NASA Astrophysics Data System (ADS)

Ezeribe, A. C.; Robinson, M.; Robinson, N.; Scarff, A.; Spooner, N. J. C.; Yuriev, L.

2018-02-01

More target mass is required in current TPC based directional dark matter detectors for improved detector sensitivity. This can be achieved by scaling up the detector volumes, but this results in the need for more analogue signal channels. A possible solution to reducing the overall cost of the charge readout electronics is to multiplex the signal readout channels. Here, we present a multiplexer system in expanded mode based on LMH6574 chips produced by Texas Instruments, originally designed for video processing. The setup has a capability of reducing the number of readouts in such TPC detectors by a factor of 20. Results indicate that the important charge distribution asymmetry along an ionization track is retained after multiplexed signals are demultiplexed.

The front-end data conversion and readout electronics for the CMS ECAL upgrade

NASA Astrophysics Data System (ADS)

Mazza, G.; Cometti, S.

2018-03-01

The High Luminosity LHC (HL-LHC) will require a significant upgrade of the readout electronics for the CMS Electromagnetic Calorimeter (ECAL). The Very Front-End (VFE) output signal will be sampled at 160 MS/s (i.e. four times the current sampling rate) with a 13 bits resolution. Therefore, a high-speed, high-resolution ADC is required. Moreover, each readout channel will produce 2.08 Gb/s, thus requiring a fast data transmission circuitry. A new readout architecture, based on two 12 bit, 160 MS/s ADCs, lossless data compression algorithms and fast serial links have been developed for the ECAL upgrade. These functions will be integrated in a single ASIC which is currently under design in a commercial CMOS 65 nm technology using radiation damage mitigation techniques.

Recent Results with CVD Diamond Trackers

NASA Astrophysics Data System (ADS)

Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K. K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knöpfle, K. T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P. F.; Manfredotti, C.; Marshall, R. D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L. S.; Palmieri, V. G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J. L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R. J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; White, C.; Ziock, H.; Zoeller, M.; RD42 Collaboration

1999-08-01

We present recent results on the use of Chemical Vapor Deposition (CVD) diamond microstrip detectors for charged particle tracking. A series of detectors was fabricated using 1 x 1 cm 2 diamonds. Good signal-to-noise ratios were observed using both slow and fast readout electronics. For slow readout electronics, 2 μs shaping time, the most probable signal-to-noise ratio was 50 to 1. For fast readout electronics, 25 ns peaking time, the most probable signal-to-noise ratio was 7 to 1. Using the first 2 x 4 cm 2 diamond from a production CVD reactor with slow readout electronics, the most probable signal-to-noise ratio was 23 to 1. The spatial resolution achieved for the detectors was consistent with the digital resolution expected from the detector pitch.

Design of an optimised readout architecture for phase-change probe memory using Ge2Sb2Te5 media

NASA Astrophysics Data System (ADS)

Wang, Lei; Wright, C. David; Aziz, Mustafa M.; Yang, Ci-Hui; Yang, Guo-Wei

2014-02-01

Phase-change probe memory has recently received considerable attention on its writing performance, while its readout performance is rarely evaluated. Therefore, a three-dimensional readout model has been developed for the first time to calculate the reading contrast by varying the electrical conductivities and the thickness of the capping and under layers as well as the thickness of the Ge2Sb2Te5 layer. It is found that a phase-change probe architecture, consisting of a 10 nm Ge2Sb2Te5 layer sandwiched by a 2 nm, 50 Ω-1 m-1 capping layer and a 40 nm, 5 × 106 Ω-1 m-1 under layer, has the capability of providing the optimal readout performance.

Quantum Algorithmic Readout in Multi-Ion Clocks.

PubMed

Schulte, M; Lörch, N; Leroux, I D; Schmidt, P O; Hammerer, K

2016-01-08

Optical clocks based on ensembles of trapped ions promise record frequency accuracy with good short-term stability. Most suitable ion species lack closed transitions, so the clock signal must be read out indirectly by transferring the quantum state of the clock ions to cotrapped logic ions of a different species. Existing methods of quantum logic readout require a linear overhead in either time or the number of logic ions. Here we describe a quantum algorithmic readout whose overhead scales logarithmically with the number of clock ions in both of these respects. The scheme allows a quantum nondemolition readout of the number of excited clock ions using a single multispecies gate operation which can also be used in other areas of ion trap technology such as quantum information processing, quantum simulations, metrology, and precision spectroscopy.

Effect of particle size on mixing degree in dispensation.

PubMed

Nakamura, Hitoshi; Yanagihara, Yoshitsugu; Sekiguchi, Hiroko; Ohtani, Michiteru; Kariya, Satoru; Uchino, Katsuyoshi; Suzuki, Hiroshi; Iga, Tatsuji

2004-03-01

By using lactose colored with erythrocin, we examined the effect of particle size on mixing degree during the preparation of triturations with a mortar and pestle. We used powders with different distributions of particle sizes, i.e., powder that passed through 32-mesh but was trapped on a 42-mesh sieve (32/42-mesh powder), powder that passed through a 42-mesh sieve but was trapped on a 60-mesh sieve (42/60-mesh powder), powder that passed through a 60-mesh sieve but was trapped on a 100-mesh sieve (60/100-mesh powder), and powder that passes through a 100-mesh sieve (> 100-mesh powder). The mixing degree of colored powder and non-colored powder whose distribution of particle sizes was the same as that of the colored powder was excellent. The coefficient of variation (CV) value of the mixing degree was 6.08% after 40 rotations when colored powder was mixed with non-colored powder that both passed through a 100-mesh sieve. The CV value of the mixing degree was low in the case of mixing of colored and non-colored powders with different particle size distributions. After mixing, about 50% of 42/60-mesh powder had become smaller particles, whereas the distribution of particle sizes was not influenced by the mixing of 60/100-mesh powder. It was suggested that the mixing degree is affected by distribution of particle sizes. It may be important to determine the mixing degrees for drugs with narrow therapeutic ranges.

An efficient and robust 3D mesh compression based on 3D watermarking and wavelet transform

NASA Astrophysics Data System (ADS)

Zagrouba, Ezzeddine; Ben Jabra, Saoussen; Didi, Yosra

2011-06-01

The compression and watermarking of 3D meshes are very important in many areas of activity including digital cinematography, virtual reality as well as CAD design. However, most studies on 3D watermarking and 3D compression are done independently. To verify a good trade-off between protection and a fast transfer of 3D meshes, this paper proposes a new approach which combines 3D mesh compression with mesh watermarking. This combination is based on a wavelet transformation. In fact, the used compression method is decomposed to two stages: geometric encoding and topologic encoding. The proposed approach consists to insert a signature between these two stages. First, the wavelet transformation is applied to the original mesh to obtain two components: wavelets coefficients and a coarse mesh. Then, the geometric encoding is done on these two components. The obtained coarse mesh will be marked using a robust mesh watermarking scheme. This insertion into coarse mesh allows obtaining high robustness to several attacks. Finally, the topologic encoding is applied to the marked coarse mesh to obtain the compressed mesh. The combination of compression and watermarking permits to detect the presence of signature after a compression of the marked mesh. In plus, it allows transferring protected 3D meshes with the minimum size. The experiments and evaluations show that the proposed approach presents efficient results in terms of compression gain, invisibility and robustness of the signature against of many attacks.

EFFECTS OF ETHYLENE OXIDE RESTERILISATION AND IN-VITRO DEGRADATION ON MECHANICAL PROPERTIES OF PARTIALLY ABSORBABLE COMPOSITE HERNIA MESHES.

PubMed

Endogan, T; Ozyaylali, I; Kulacoglu, H; Serbetci, K; Kiyak, G; Hasirci, N

2013-06-01

Prosthetic mesh repair for abdominal wall hernias is widely used because of its technical simplicity and low hernia recurrence rates. The most commonly used material is pure polypropylene mesh, however newer composite materials are recommended by some centers because of their advantages. However, these meshes are more expensive than pure polypropylene meshes. Resterilisation of a pure polypropylene mesh has been shown to be quite safe, and many centers prefer slicing a large mesh into smaller pieces that suitable for hernia type or defect size. Nevertheless there is no data about the safety after resterilisation of the composite meshes. To search the effects of resterilisation and In vitro degradation in phosphate buffered saline solution on the physical structure and the mechanical properties of partially absorbable lightweigth meshes. Laboratory-based research. Two composite meshes were used in the study: One mesh is consisted of monofilament polypropylene and monofilament polyglecaprone--a copolymer of glycolide and epsilon (ε)-caprolactone--(Ultrapro®, 28 g/m2, Ethicon, Hamburg, Germany),andthe otherone consisted of multifilamentpolypropyleneandmultifilament polyglactine (Vypro II®, 30 g/m2,Ethicon, Hamburg, Germany). Two large meshes were cut into rectangular specimens sized 50x20 mm for mechanical testing and 20x20 mm for In vitro degradation experiments. Meshes were divided into control group with no resterilisation and gas resterilisation. Ethylene oxide gas sterilisation was performed at 55°C for 4.5 hours. In vitro degradation in 0.01 M phosphate buffered saline (PBS, pH 7.4) solution at 37 ± 1°C for 8 weeks was applied to one subgroup in each mesh group. Tensiometric measurements and scanning electron microscopyic evaluations were completed for control and resterilisation specimens. Regardless of resterilisation, when meshes were exposed to In vitro degradation, all mechanical parameters decreased significantly. Highest reduction in mechanical properties was observed for Ultrapro due to the degradation of absorbable polyglecaprone and polyglactin parts of these meshes. It was observed that resterilisation by ethylene oxide did not have significant difference on the degradation characteristics and almost similar physical structures were observed for resterilised and non-resterilised meshes. For Vypro II meshes, no significant mechanical difference was observedbetweenresterilised andnon-resterilised meshes after degradationwhile resterilised Ultrapro meshes exhibited stronger characteristics than non-resterilised counterparts, after degradation. Resterilisation with ethylene oxide did not affect the mechanical properties of partially absorbable composite meshes. No important surface changeswere observed in scanning electron microscopy after resterilisation.

Large Format CMOS-based Detectors for Diffraction Studies

NASA Astrophysics Data System (ADS)

Thompson, A. C.; Nix, J. C.; Achterkirchen, T. G.; Westbrook, E. M.

2013-03-01

Complementary Metal Oxide Semiconductor (CMOS) devices are rapidly replacing CCD devices in many commercial and medical applications. Recent developments in CMOS fabrication have improved their radiation hardness, device linearity, readout noise and thermal noise, making them suitable for x-ray crystallography detectors. Large-format (e.g. 10 cm × 15 cm) CMOS devices with a pixel size of 100 μm × 100 μm are now becoming available that can be butted together on three sides so that very large area detector can be made with no dead regions. Like CCD systems our CMOS systems use a GdOS:Tb scintillator plate to convert stopping x-rays into visible light which is then transferred with a fiber-optic plate to the sensitive surface of the CMOS sensor. The amount of light per x-ray on the sensor is much higher in the CMOS system than a CCD system because the fiber optic plate is only 3 mm thick while on a CCD system it is highly tapered and much longer. A CMOS sensor is an active pixel matrix such that every pixel is controlled and readout independently of all other pixels. This allows these devices to be readout while the sensor is collecting charge in all the other pixels. For x-ray diffraction detectors this is a major advantage since image frames can be collected continuously at up 20 Hz while the crystal is rotated. A complete diffraction dataset can be collected over five times faster than with CCD systems with lower radiation exposure to the crystal. In addition, since the data is taken fine-phi slice mode the 3D angular position of diffraction peaks is improved. We have developed a cooled 6 sensor CMOS detector with an active area of 28.2 × 29.5 cm with 100 μm × 100 μm pixels and a readout rate of 20 Hz. The detective quantum efficiency exceeds 60% over the range 8-12 keV. One, two and twelve sensor systems are also being developed for a variety of scientific applications. Since the sensors are butt able on three sides, even larger systems could be built at reasonable cost.

Improving radiation hardness in space-based Charge-Coupled Devices through the narrowing of the charge transfer channel

NASA Astrophysics Data System (ADS)

Hall, D. J.; Skottfelt, J.; Soman, M. R.; Bush, N.; Holland, A.

2017-12-01

Charge-Coupled Devices (CCDs) have been the detector of choice for imaging and spectroscopy in space missions for several decades, such as those being used for the Euclid VIS instrument and baselined for the SMILE SXI. Despite the many positive properties of CCDs, such as the high quantum efficiency and low noise, when used in a space environment the detectors suffer damage from the often-harsh radiation environment. High energy particles can create defects in the silicon lattice which act to trap the signal electrons being transferred through the device, reducing the signal measured and effectively increasing the noise. We can reduce the impact of radiation on the devices through four key methods: increased radiation shielding, device design considerations, optimisation of operating conditions, and image correction. Here, we concentrate on device design operations, investigating the impact of narrowing the charge-transfer channel in the device with the aim of minimising the impact of traps during readout. Previous studies for the Euclid VIS instrument considered two devices, the e2v CCD204 and CCD273, the serial register of the former having a 50 μm channel and the latter having a 20 μm channel. The reduction in channel width was previously modelled to give an approximate 1.6× reduction in charge storage volume, verified experimentally to have a reduction in charge transfer inefficiency of 1.7×. The methods used to simulate the reduction approximated the charge cloud to a sharp-edged volume within which the probability of capture by traps was 100%. For high signals and slow readout speeds, this is a reasonable approximation. However, for low signals and higher readout speeds, the approximation falls short. Here we discuss a new method of simulating and calculating charge storage variations with device design changes, considering the absolute probability of capture across the pixel, bringing validity to all signal sizes and readout speeds. Using this method, we can optimise the device design to suffer minimum impact from radiation damage effects, here using detector development for the SMILE mission to demonstrate the process.

Optimization of an ultralow-dose high-resolution pediatric PET scanner design based on monolithic scintillators with dual-sided digital SiPM readout: a simulation study

NASA Astrophysics Data System (ADS)

Mikhaylova, Ekaterina; Tabacchini, Valerio; Borghi, Giacomo; Mollet, Pieter; D'Hoe, Ester; Schaart, Dennis R.; Vandenberghe, Stefaan

2017-11-01

The goal of this simulation study is the performance evaluation and comparison of six potential designs for a time-of-flight PET scanner for pediatric patients of up to about 12 years of age. It is designed to have a high sensitivity and provide high-contrast and high-resolution images. The simulated pediatric PET is a full ring scanner, consisting of 32  ×  32 mm2 monolithic LYSO:Ce crystals coupled to digital silicon photomultiplier arrays. The six considered designs differ in axial lengths (27.2 cm, 54.4 cm and 102 cm) and crystal thicknesses (22 mm and 11 mm). The simulations are based on measured detector response data. We study two possible detector arrangements: 22 mm-thick crystals with dual-sided readout and 11 mm-thick crystals with back-sided readout. The six designs are simulated by means of the GEANT4 application for tomographic emission software, using the measured spatial, energy and time response of the monolithic scintillator detectors as input. The performance of the six designs is compared on the basis of four studies: (1) spatial resolution; (2) NEMA NU2-2012 sensitivity and scatter fraction (SF) tests; (3) non-prewhitening signal-to-noise ratio observer study; and (4) receiver operating characteristics analysis. Based on the results, two designs are identified as cost-effective solutions for fast and efficient imaging of children: one with 54.4 cm axial field-of-view (FOV) and 22 mm-thick crystals, and another one with 102 cm axial FOV and 11 cm-thick crystals. The first one has a higher center point sensitivity than the second one, but requires dual-sided readout. The second design has the advantage of allowing a whole-body scan in a single bed position acquisition. Both designs have the potential to provide an excellent spatial resolution (˜2 mm) and an ultra-high sensitivity (>100 cps kBq-1 ).

MO-F-CAMPUS-J-03: Development of a Human Brain PET for On-Line Proton Beam-Range Verification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shao, Yiping

Purpose: To develop a prototype PET for verifying proton beam-range before each fractionated therapy that will enable on-line re-planning proton therapy. Methods: Latest “edge-less” silicon photomultiplier arrays and customized ASIC readout electronics were used to develop PET detectors with depth-of-interaction (DOI) measurement capability. Each detector consists of one LYSO array with each end coupled to a SiPM array. Multiple detectors can be seamlessly tiled together to form a large detector panel. Detectors with 1.5×1.5 and 2.0×2.0 mm crystals at 20 or 30 mm lengths were studied. Readout of individual SiPM or signal multiplexing was used to transfer 3D interaction position-codedmore » analog signals through flexible-print-circuit cables or PCB board to dedicated ASIC front-end electronics to output digital timing pulses that encode interaction information. These digital pulses can be transferred to, through standard LVDS cables, and decoded by a FPGA-based data acquisition of coincidence events and data transfer. The modular detector and scalable electronics/data acquisition will enable flexible PET system configuration for different imaging geometry. Results: Initial detector performance measurement shows excellent crystal identification even with 30 mm long crystals, ∼18% and 2.8 ns energy and timing resolutions, and around 2–3 mm DOI resolution. A small prototype PET scanner with one detector ring has been built and evaluated, validating the technology and design. A large size detector panel has been fabricated by scaling up from modular detectors. Different designs of resistor and capacitor based signal multiplexing boards were tested and selected based on optimal crystal identification and timing performance. Stackable readout electronics boards and FPGA-based data acquisition boards were developed and tested. A brain PET is under construction. Conclusion: Technology of large-size DOI detector based on SiPM array and advanced readout has been developed. PET imaging performance and initial phantom studies of on-line proton beam-range measurement will be conducted and reported. NIH grant R21CA187717; Cancer Prevention and Research Institute of Texas grant RP120326.« less

Minimizing finite-volume discretization errors on polyhedral meshes

NASA Astrophysics Data System (ADS)

Mouly, Quentin; Evrard, Fabien; van Wachem, Berend; Denner, Fabian

2017-11-01

Tetrahedral meshes are widely used in CFD to simulate flows in and around complex geometries, as automatic generation tools now allow tetrahedral meshes to represent arbitrary domains in a relatively accessible manner. Polyhedral meshes, however, are an increasingly popular alternative. While tetrahedron have at most four neighbours, the higher number of neighbours per polyhedral cell leads to a more accurate evaluation of gradients, essential for the numerical resolution of PDEs. The use of polyhedral meshes, nonetheless, introduces discretization errors for finite-volume methods: skewness and non-orthogonality, which occur with all sorts of unstructured meshes, as well as errors due to non-planar faces, specific to polygonal faces with more than three vertices. Indeed, polyhedral mesh generation algorithms cannot, in general, guarantee to produce meshes free of non-planar faces. The presented work focuses on the quantification and optimization of discretization errors on polyhedral meshes in the context of finite-volume methods. A quasi-Newton method is employed to optimize the relevant mesh quality measures. Various meshes are optimized and CFD results of cases with known solutions are presented to assess the improvements the optimization approach can provide.

LBMD : a layer-based mesh data structure tailored for generic API infrastructures.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebeida, Mohamed S.; Knupp, Patrick Michael

2010-11-01

A new mesh data structure is introduced for the purpose of mesh processing in Application Programming Interface (API) infrastructures. This data structure utilizes a reduced mesh representation to increase its ability to handle significantly larger meshes compared to full mesh representation. In spite of the reduced representation, each mesh entity (vertex, edge, face, and region) is represented using a unique handle, with no extra storage cost, which is a crucial requirement in most API libraries. The concept of mesh layers makes the data structure more flexible for mesh generation and mesh modification operations. This flexibility can have a favorable impactmore » in solver based queries of finite volume and multigrid methods. The capabilities of LBMD make it even more attractive for parallel implementations using Message Passing Interface (MPI) or Graphics Processing Units (GPUs). The data structure is associated with a new classification method to relate mesh entities to their corresponding geometrical entities. The classification technique stores the related information at the node level without introducing any ambiguities. Several examples are presented to illustrate the strength of this new data structure.« less

Improved quality of intrafraction kilovoltage images by triggered readout of unexposed frames

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poulsen, Per Rugaard, E-mail: per.poulsen@rm.dk; Jonassen, Johnny; Jensen, Carsten

2015-11-15

Purpose: The gantry-mounted kilovoltage (kV) imager of modern linear accelerators can be used for real-time tumor localization during radiation treatment delivery. However, the kV image quality often suffers from cross-scatter from the megavoltage (MV) treatment beam. This study investigates readout of unexposed kV frames as a means to improve the kV image quality in a series of experiments and a theoretical model of the observed image quality improvements. Methods: A series of fluoroscopic images were acquired of a solid water phantom with an embedded gold marker and an air cavity with and without simultaneous radiation of the phantom with amore » 6 MV beam delivered perpendicular to the kV beam with 300 and 600 monitor units per minute (MU/min). An in-house built device triggered readout of zero, one, or multiple unexposed frames between the kV exposures. The unexposed frames contained part of the MV scatter, consequently reducing the amount of MV scatter accumulated in the exposed frames. The image quality with and without unexposed frame readout was quantified as the contrast-to-noise ratio (CNR) of the gold marker and air cavity for a range of imaging frequencies from 1 to 15 Hz. To gain more insight into the observed CNR changes, the image lag of the kV imager was measured and used as input in a simple model that describes the CNR with unexposed frame readout in terms of the contrast, kV noise, and MV noise measured without readout of unexposed frames. Results: Without readout of unexposed kV frames, the quality of intratreatment kV images decreased dramatically with reduced kV frequencies due to MV scatter. The gold marker was only visible for imaging frequencies ≥3 Hz at 300 MU/min and ≥5 Hz for 600 MU/min. Visibility of the air cavity required even higher imaging frequencies. Readout of multiple unexposed frames ensured visibility of both structures at all imaging frequencies and a CNR that was independent of the kV frame rate. The image lag was 12.2%, 2.2%, and 0.9% in the first, second, and third frame after an exposure. The CNR model predicted the CNR with triggered image readout with a mean absolute error of 2.0% for the gold marker. Conclusions: A device that triggers readout of unexposed frames during kV fluoroscopy was built and shown to greatly improve the quality of intratreatment kV images. A simple theoretical model successfully described the CNR improvements with the device.« less

Anterior pelvic organ prolapse repair using synthetic mesh.

PubMed

Patel, Bhavin N; Lucioni, Alvaro; Kobashi, Kathleen C

2012-06-01

Since the U.S. Food and Drug Administration (FDA) statement on mesh in July of 2011, there has been controversy regarding synthetic mesh repairs for vaginal prolapse. In this article, we review the biochemical basis for the use of synthetic mesh in prolapse repair as well as clinical results of anterior compartment prolapse repair with synthetic mesh. Finally, we discuss the FDA warning regarding mesh.

Quality of pharmacy-specific Medical Subject Headings (MeSH) assignment in pharmacy journals indexed in MEDLINE.

PubMed

Minguet, Fernando; Salgado, Teresa M; van den Boogerd, Lucienne; Fernandez-Llimos, Fernando

2015-01-01

The Medical Subject Headings (MeSH) is the National Library of Medicine (NLM) controlled vocabulary for indexing articles. Inaccuracies in the MeSH thesaurus have been reported for several areas including pharmacy. To assess the quality of pharmacy-specific MeSH assignment to articles indexed in pharmacy journals. The 10 journals containing the highest number of articles published in 2012 indexed under the MeSH 'Pharmacists' were identified. All articles published over a 5-year period (2008-2012) in the 10 previously selected journals were retrieved from PubMed. MeSH terms used to index these articles were extracted and pharmacy-specific MeSH terms were identified. The frequency of use of pharmacy-specific MeSH terms was calculated across journals. A total of 6989 articles were retrieved from the 10 pharmacy journals, of which 328 (4.7%) were articles not fully indexed and therefore did not contain any MeSH terms assigned. Among the 6661 articles fully indexed, the mean number of MeSH terms was 10.1 (SD = 4.0), being 1.0 (SD = 1.3) considered as Major MeSH. Both values significantly varied across journals. The mean number of pharmacy-specific MeSH terms per article was 0.9 (SD = 1.2). A total of 3490 (52.4%) of the 6661 articles were indexed in pharmacy journals without a single pharmacy-specific MeSH. Of the total 67193 MeSH terms assigned to articles, on average 10.5% (SD = 13.9) were pharmacy-specific MeSH. A statistically significant different pattern of pharmacy-specific MeSH assignment was identified across journals (Kruskal-Wallis P < 0.001). The quality of assignment of the existing pharmacy-specific MeSH terms to articles indexed in pharmacy journals can be improved to further enhance evidence gathering in pharmacy. Over half of the articles published in the top-10 journals publishing pharmacy literature were indexed without a single pharmacy-specific MeSH. Copyright © 2015 Elsevier Inc. All rights reserved.

Design and Strength check of Large Blow Molding Machine Rack

NASA Astrophysics Data System (ADS)

Fei-fei, GU; Zhi-song, ZHU; Xiao-zhao, YAN; Yi-min, ZHU

Design procedure of large blow moulding machine rack is discussed in the article. A strength checking method is presented. Finite element analysis is conducted in the design procedure by ANSYS software. The actual situation of the rack load bearing is fully considered. The necessary means to simplify the model are done. The dimensional linear element Beam 188 is analyzed. MESH200 is used to mesh. Therefore, it simplifies the analysis process and improves computational efficiency. The maximum deformation of rack is 8.037 mm: it is occurred in the position of accumulator head. The result states: it meets the national standard curvature which is not greater than 0.3% of the total channel length; it also meets strength requirement that the maximum stress was 54.112 MPa.

Tissue response to collagen containing polypropylene meshes in an ovine vaginal repair model.

PubMed

Darzi, Saeedeh; Urbankova, Iva; Su, Kai; White, Jacinta; Lo, Camden; Alexander, David; Werkmeister, Jerome A; Gargett, Caroline E; Deprest, Jan

2016-07-15

Pelvic Organ Prolapse (POP) is the herniation of pelvic organs into the vagina. Despite broad acceptance of mesh use in POP surgical repair, the complication rate is unacceptable. We hypothesized that collagen-containing polypropylene (PP) mesh types could modulate mesh-tissue integration and reduce long-term inflammation, thereby reducing mesh-associated complications. This study compared the long-term tissue response to an unmodified PP mesh and two collagen containing meshes in an ovine model which has similar pelvic anatomy and vaginal size to human. Three commercially available macroporous PP meshes, uncoated PP mesh (Avaulta Solo) (PP), the same textile PP mesh layered with a sheet of cross-linked porcine acellular matrix (Avaulta Plus) (PP-ACM) and a different yet also macroporous PP (Sofradim) mesh coated with solubilized atelocollagen (Ugytex) (PP-sCOL) were implanted in the ovine vagina and tissue explanted after 60 and 180days. The macrophage phenotype and response to implanted meshes, and vascularity were quantified by immunostaining and morphometry. We quantified changes in extracellular matrix composition biochemically and collagen organisation and percentage area around the interface of the mesh implants by Sirius Red birefringence and morphometry. PP-ACM induced a more sustained inflammatory response, indicated by similar CD45(+) leukocytes but reduced CD163(+) M2 macrophages at 60days (P<0.05). PP-sCOL increased Von Willebrand Factor (vWF)-immunoreactive vessel profiles after 60days. At the micro-molecular level, collagen birefringence quantification revealed significantly fewer mature collagen fibrils (red, thick fibrils) at the mesh-tissue interface than control tissue for all mesh types (P<0.001) but still significantly greater than the proportion of immature (green thin fibrils) at 60days (P<0.05). The proportion of mature collagen fibrils increased with time around the mesh filaments, particularly those containing collagen. The total collagen percent area at the mesh interface was greatest around the PP-ACM mesh at 60days (P<0.05). By 180days the total mature and immature collagen fibres at the interface of the mesh filaments resembled that of native tissue. In particular, these results suggest that both meshes containing collagen evoke different types of tissue responses at different times during the healing response yet both ultimately lead to physiological tissue formation approaching that of normal tissue. Pelvic organ prolapse (POP) is the descent of the pelvic organs to the vagina. POP affects more than 25% of all women and the lifetime risk of undergoing POP surgery is 19%. Although synthetic polypropylene (PP) meshes have improved the outcome of the surgical treatment for POP, there was an unacceptable rate of adverse events including mesh exposure and contracture. It is hypothesized that coating the PP meshes with collagen would provide a protective effect by preventing severe mesh adhesions to the wound, resulting in a better controlled initial inflammatory response, and diminished risk of exposure. In this study we assessed the effect of two collagen-containing PP meshes on the long-term vaginal tissue response using new techniques to quantify these tissue responses. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effect of boundary representation on viscous, separated flows in a discontinuous-Galerkin Navier-Stokes solver

NASA Astrophysics Data System (ADS)

Nelson, Daniel A.; Jacobs, Gustaaf B.; Kopriva, David A.

2016-08-01

The effect of curved-boundary representation on the physics of the separated flow over a NACA 65(1)-412 airfoil is thoroughly investigated. A method is presented to approximate curved boundaries with a high-order discontinuous-Galerkin spectral element method for the solution of the Navier-Stokes equations. Multiblock quadrilateral element meshes are constructed with the grid generation software GridPro. The boundary of a NACA 65(1)-412 airfoil, defined by a cubic natural spline, is piecewise-approximated by isoparametric polynomial interpolants that represent the edges of boundary-fitted elements. Direct numerical simulation of the airfoil is performed on a coarse mesh and fine mesh with polynomial orders ranging from four to twelve. The accuracy of the curve fitting is investigated by comparing the flows computed on curved-sided meshes with those given by straight-sided meshes. Straight-sided meshes yield irregular wakes, whereas curved-sided meshes produce a regular Karman street wake. Straight-sided meshes also produce lower lift and higher viscous drag as compared with curved-sided meshes. When the mesh is refined by reducing the sizes of the elements, the lift decrease and viscous drag increase are less pronounced. The differences in the aerodynamic performance between the straight-sided meshes and the curved-sided meshes are concluded to be the result of artificial surface roughness introduced by the piecewise-linear boundary approximation provided by the straight-sided meshes.

Design and simulation of a novel method for determining depth-of-interaction in a PET scintillation crystal array using a single-ended readout by a multi-anode PMT

NASA Astrophysics Data System (ADS)

Ito, Mikiko; Lee, Jae Sung; Park, Min-Jae; Sim, Kwang-Souk; Jong Hong, Seong

2010-07-01

PET detectors with depth-of-interaction (DOI) encoding capability allow high spatial resolution and high sensitivity to be achieved simultaneously. To obtain DOI information from a mono-layer array of scintillation crystals using a single-ended readout, the authors devised a method based on light spreading within a crystal array and performed Monte Carlo simulations with individual scintillation photon tracking to prove the concept. A scintillation crystal array model was constructed using a grid method. Conventional grids are constructed using comb-shaped reflector strips with rectangular teeth to isolate scintillation crystals optically. However, the authors propose the use of triangularly shaped teeth, such that scintillation photons spread only in the x-direction in the upper halves of crystals and in the y-direction in lower halves. DOI positions can be estimated by considering the extent of two-dimensional light dispersion, which can be determined from the multiple anode outputs of a position-sensitive PMT placed under the crystal array. In the main simulation, a crystal block consisting of a 29 × 29 array of 1.5 mm × 1.5 mm × 20 mm crystals and a multi-anode PMT with 16 × 16 pixels were used. The effects of crystal size and non-uniform PMT output gain were also explored by simulation. The DOI resolution estimated for 1.5 × 1.5 × 20 mm3 crystals was 2.16 mm on average. Although the flood map was depth dependent, each crystal was well identified at all depths when a corner of the crystal array was irradiated with 511 keV gamma rays (peak-to-valley ratio ~9:1). DOI resolution was better than 3 mm up to a crystal length of 28 mm with a 1.5 × 1.5 mm2 or 2.0 × 2.0 mm2 crystal surface area. The devised light-sharing method allowed excellent DOI resolutions to be obtained without the use of dual-ended readout or multiple crystal arrays.

Development of a Crosstalk Suppression Algorithm for KID Readout

NASA Astrophysics Data System (ADS)

Lee, Kyungmin; Ishitsuka, H.; Oguri, S.; Suzuki, J.; Tajima, O.; Tomita, N.; Won, Eunil; Yoshida, M.

2018-06-01

The GroundBIRD telescope aims to detect B-mode polarization of the cosmic microwave background radiation using the kinetic inductance detector array as a polarimeter. For the readout of the signal from detector array, we have developed a frequency division multiplexing readout system based on a digital down converter method. These techniques in general have the leakage problems caused by the crosstalks. The window function was applied in the field programmable gate arrays to mitigate the effect of these problems and tested it in algorithm level.

Tunneling Statistics for Analysis of Spin-Readout Fidelity

NASA Astrophysics Data System (ADS)

Gorman, S. K.; He, Y.; House, M. G.; Keizer, J. G.; Keith, D.; Fricke, L.; Hile, S. J.; Broome, M. A.; Simmons, M. Y.

2017-09-01

We investigate spin and charge dynamics of a quantum dot of phosphorus atoms coupled to a radio-frequency single-electron transistor (SET) using full counting statistics. We show how the magnetic field plays a role in determining the bunching or antibunching tunneling statistics of the donor dot and SET system. Using the counting statistics, we show how to determine the lowest magnetic field where spin readout is possible. We then show how such a measurement can be used to investigate and optimize single-electron spin-readout fidelity.

Superconducting thin-film gyroscope readout for Gravity Probe-B

NASA Technical Reports Server (NTRS)

Lockhart, James M.; Cheung, W. Stephen; Gill, Dale K.

1987-01-01

The high-resolution gyroscope readout system for the Stanford Gravity Probe-B experiment, whose purpose is to measure two general relativistic precessions of gyroscopes in earth orbit, is described. In order to achieve the required resolution in angle (0.001 arcsec), the readout system combines high-precision mechanical fabrication and measurement techniques with superconducting thin-film technology, ultralow magnetic fields, and SQUID detectors. The system design, performance limits achievable with current technology, and the results of fabrication and laboratory testing to date are discussed.