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Sample records for active pixel matrix

  1. Monolithic Active Pixel Matrix with Binary Counters (MAMBO) ASIC

    SciTech Connect

    Khalid, Farah F.; Deptuch, Grzegorz; Shenai, Alpana; Yarema, Raymond J.; /Fermilab

    2010-11-01

    Monolithic Active Matrix with Binary Counters (MAMBO) is a counting ASIC designed for detecting and measuring low energy X-rays from 6-12 keV. Each pixel contains analogue functionality implemented with a charge preamplifier, CR-RC{sup 2} shaper and a baseline restorer. It also contains a window comparator which can be trimmed by 4 bit DACs to remove systematic offsets. The hits are registered by a 12 bit ripple counter which is reconfigured as a shift register to serially output the data from the entire ASIC. Each pixel can be tested individually. Two diverse approaches have been used to prevent coupling between the detector and electronics in MAMBO III and MAMBO IV. MAMBO III is a 3D ASIC, the bottom ASIC consists of diodes which are connected to the top ASIC using {mu}-bump bonds. The detector is decoupled from the electronics by physically separating them on two tiers and using several metal layers as a shield. MAMBO IV is a monolithic structure which uses a nested well approach to isolate the detector from the electronics. The ASICs are being fabricated using the SOI 0.2 {micro}m OKI process, MAMBO III is 3D bonded at T-Micro and MAMBO IV nested well structure was developed in collaboration between OKI and Fermilab.

  2. Energy-recycling pixel for active-matrix organic light-emitting diode display

    NASA Astrophysics Data System (ADS)

    Yang, Che-Yu; Cho, Ting-Yi; Chen, Yen-Yu; Yang, Chih-Jen; Meng, Chao-Yu; Yang, Chieh-Hung; Yang, Po-Chuan; Chang, Hsu-Yu; Hsueh, Chun-Yuan; Wu, Chung-Chih; Lee, Si-Chen

    2007-06-01

    The authors report a pixel structure for active-matrix organic light-emitting diode (OLED) displays that has a hydrogenated amorphous silicon solar cell inserted between the driving polycrystalline Si thin-film transistor and the pixel OLED. Such an active-matrix OLED pixel structure not only exhibits a reduced reflection (and thus improved contrast) compared to conventional OLEDs but also is capable of recycling both incident photon energies and internally generated OLED radiation. Such a feature of energy recycling may be of use for portable/mobile electronics, which are particularly power aware.

  3. MONOLITHIC ACTIVE PIXEL MATRIX WITH BINARY COUNTERS IN AN SOI PROCESS.

    SciTech Connect

    DUPTUCH,G.; YAREMA, R.

    2007-06-07

    The design of a Prototype monolithic active pixel matrix, designed in a 0.15 {micro}m CMOS SOI Process, is presented. The process allowed connection between the electronics and the silicon volume under the layer of buried oxide (BOX). The small size vias traversing through the BOX and implantation of small p-type islands in the n-type bulk result in a monolithic imager. During the acquisition time, all pixels register individual radiation events incrementing the counters. The counting rate is up to 1 MHz per pixel. The contents of counters are shifted out during the readout phase. The designed prototype is an array of 64 x 64 pixels and the pixel size is 26 x 26 {micro}m{sup 2}.

  4. Low Temperature Polycrystalline Silicon Thin Film Transistor Pixel Circuits for Active Matrix Organic Light Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Fan, Ching-Lin; Lin, Yu-Sheng; Liu, Yan-Wei

    A new pixel design and driving method for active matrix organic light emitting diode (AMOLED) displays that use low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) with a voltage programming method are proposed and verified using the SPICE simulator. We had employed an appropriate TFT model in SPICE simulation to demonstrate the performance of the pixel circuit. The OLED anode voltage variation error rates are below 0.35% under driving TFT threshold voltage deviation (Δ Vth =± 0.33V). The OLED current non-uniformity caused by the OLED threshold voltage degradation (Δ VTO =+0.33V) is significantly reduced (below 6%). The simulation results show that the pixel design can improve the display image non-uniformity by compensating for the threshold voltage deviation in the driving TFT and the OLED threshold voltage degradation at the same time.

  5. Monolithic Active Pixel Matrix with Binary Counters ASIC with nested wells

    NASA Astrophysics Data System (ADS)

    Fahim, F.; Deptuch, G.; Holm, S.; Shenai, A.; Lipton, R.

    2013-04-01

    Monolithic Active Matrix with Binary Counters (MAMBO) V ASIC has been designed for detecting and measuring low energy X-rays. A nested well structure with a buried n-well (BNW) and a deeper buried p-well (BPW) is used to electrically isolate the detector from the electronics. BNW acts as an AC ground to electrical signals and behaves as a shield. BPW allows for a homogenous electric field in the entire detector volume. The ASIC consists of a matrix of 50 × 52 pixels, each of 105x105μm2. Each pixel contains analog functionality accomplished by a charge preamplifier, CR-RC2 shaper and a baseline restorer. It also contains a window comparator with Upper and Lower thresholds which can be individually trimmed by 4 bit DACs to remove systematic offsets. The hits are registered by a 12 bit counter which is reconfigured as a shift register to serially output the data from the entire ASIC.

  6. Enhanced Pixel-Driving Circuits for Active-Matrix Organic-Light-Emitting Diode Displays with Large Sizes

    NASA Astrophysics Data System (ADS)

    Yu, Sang Ho; Choi, Sung Wook; Shin, Hong Jae; Kwack, Kae Dal; Kim, Tae Whan

    2005-03-01

    Enhanced pixel-driving circuits for active-matrix organic-light-emitting diode (AM-OLED) displays with large sizes and highly uniform brightnesses were designed for system on panel. The driving method used the pre-charge functions of the data for a highly uniform brightness during a short time to program the current. The currents of the designed pixel-driving circuits were not significantly affected by variations in the threshold voltages, or by the mobilities of the driving thin-film transistors. These results indicate that the proposed pixel-driving circuits hold promise for potential applications in AM-OLED displays with large sizes and highly uniform brightnesses.

  7. A New Low Temperature Polycrystalline Silicon Thin Film Transistor Pixel Circuit for Active Matrix Organic Light Emitting Diode

    NASA Astrophysics Data System (ADS)

    Ching-Lin Fan,; Yi-Yan Lin,; Jyu-Yu Chang,; Bo-Jhang Sun,; Yan-Wei Liu,

    2010-06-01

    This study presents one novel compensation pixel design and driving method for active matrix organic light-emitting diode (AMOLED) displays that use low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) with a voltage feed-back method and the simulation results are proposed and verified by SPICE simulator. The measurement and simulation of LTPS TFT characteristics demonstrate the good fitting result. The proposed circuit consists of four TFTs and two capacitors with an additional signal line. The error rates of OLED anode voltage variation are below 0.3% under the threshold voltage deviation of driving TFT (Δ VTH = ± 0.33 V). The simulation results show that the pixel design can improve the display image non-uniformity by compensating the threshold voltage deviation of driving TFT and the degradation of OLED threshold voltage at the same time.

  8. A New Low Temperature Polycrystalline Silicon Thin Film Transistor Pixel Circuit for Active Matrix Organic Light Emitting Diode

    NASA Astrophysics Data System (ADS)

    Fan, Ching-Lin; Lin, Yi-Yan; Chang, Jyu-Yu; Sun, Bo-Jhang; Liu, Yan-Wei

    2010-06-01

    This study presents one novel compensation pixel design and driving method for active matrix organic light-emitting diode (AMOLED) displays that use low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) with a voltage feed-back method and the simulation results are proposed and verified by SPICE simulator. The measurement and simulation of LTPS TFT characteristics demonstrate the good fitting result. The proposed circuit consists of four TFTs and two capacitors with an additional signal line. The error rates of OLED anode voltage variation are below 0.3% under the threshold voltage deviation of driving TFT (ΔVTH = ±0.33 V). The simulation results show that the pixel design can improve the display image non-uniformity by compensating the threshold voltage deviation of driving TFT and the degradation of OLED threshold voltage at the same time.

  9. High-Sensitivity X-ray Polarimetry with Amorphous Silicon Active-Matrix Pixel Proportional Counters

    NASA Technical Reports Server (NTRS)

    Black, J. K.; Deines-Jones, P.; Jahoda, K.; Ready, S. E.; Street, R. A.

    2003-01-01

    Photoelectric X-ray polarimeters based on pixel micropattern gas detectors (MPGDs) offer order-of-magnitude improvement in sensitivity over more traditional techniques based on X-ray scattering. This new technique places some of the most interesting astronomical observations within reach of even a small, dedicated mission. The most sensitive instrument would be a photoelectric polarimeter at the focus of 2 a very large mirror, such as the planned XEUS. Our efforts are focused on a smaller pathfinder mission, which would achieve its greatest sensitivity with large-area, low-background, collimated polarimeters. We have recently demonstrated a MPGD polarimeter using amorphous silicon thin-film transistor (TFT) readout suitable for the focal plane of an X-ray telescope. All the technologies used in the demonstration polarimeter are scalable to the areas required for a high-sensitivity collimated polarimeter. Leywords: X-ray polarimetry, particle tracking, proportional counter, GEM, pixel readout

  10. An investigation of signal performance enhancements achieved through innovative pixel design across several generations of indirect detection, active matrix, flat-panel arrays

    SciTech Connect

    Antonuk, Larry E.; Zhao Qihua; El-Mohri, Youcef; Du Hong; Wang Yi; Street, Robert A.; Ho, Jackson; Weisfield, Richard; Yao, William

    2009-07-15

    Active matrix flat-panel imager (AMFPI) technology is being employed for an increasing variety of imaging applications. An important element in the adoption of this technology has been significant ongoing improvements in optical signal collection achieved through innovations in indirect detection array pixel design. Such improvements have a particularly beneficial effect on performance in applications involving low exposures and/or high spatial frequencies, where detective quantum efficiency is strongly reduced due to the relatively high level of additive electronic noise compared to signal levels of AMFPI devices. In this article, an examination of various signal properties, as determined through measurements and calculations related to novel array designs, is reported in the context of the evolution of AMFPI pixel design. For these studies, dark, optical, and radiation signal measurements were performed on prototype imagers incorporating a variety of increasingly sophisticated array designs, with pixel pitches ranging from 75 to 127 {mu}m. For each design, detailed measurements of fundamental pixel-level properties conducted under radiographic and fluoroscopic operating conditions are reported and the results are compared. A series of 127 {mu}m pitch arrays employing discrete photodiodes culminated in a novel design providing an optical fill factor of {approx}80% (thereby assuring improved x-ray sensitivity), and demonstrating low dark current, very low charge trapping and charge release, and a large range of linear signal response. In two of the designs having 75 and 90 {mu}m pitches, a novel continuous photodiode structure was found to provide fill factors that approach the theoretical maximum of 100%. Both sets of novel designs achieved large fill factors by employing architectures in which some, or all of the photodiode structure was elevated above the plane of the pixel addressing transistor. Generally, enhancement of the fill factor in either discrete or

  11. An investigation of signal performance enhancements achieved through innovative pixel design across several generations of indirect detection, active matrix, flat-panel arrays

    PubMed Central

    Antonuk, Larry E.; Zhao, Qihua; El-Mohri, Youcef; Du, Hong; Wang, Yi; Street, Robert A.; Ho, Jackson; Weisfield, Richard; Yao, William

    2009-01-01

    Active matrix flat-panel imager (AMFPI) technology is being employed for an increasing variety of imaging applications. An important element in the adoption of this technology has been significant ongoing improvements in optical signal collection achieved through innovations in indirect detection array pixel design. Such improvements have a particularly beneficial effect on performance in applications involving low exposures and∕or high spatial frequencies, where detective quantum efficiency is strongly reduced due to the relatively high level of additive electronic noise compared to signal levels of AMFPI devices. In this article, an examination of various signal properties, as determined through measurements and calculations related to novel array designs, is reported in the context of the evolution of AMFPI pixel design. For these studies, dark, optical, and radiation signal measurements were performed on prototype imagers incorporating a variety of increasingly sophisticated array designs, with pixel pitches ranging from 75 to 127 μm. For each design, detailed measurements of fundamental pixel-level properties conducted under radiographic and fluoroscopic operating conditions are reported and the results are compared. A series of 127 μm pitch arrays employing discrete photodiodes culminated in a novel design providing an optical fill factor of ∼80% (thereby assuring improved x-ray sensitivity), and demonstrating low dark current, very low charge trapping and charge release, and a large range of linear signal response. In two of the designs having 75 and 90 μm pitches, a novel continuous photodiode structure was found to provide fill factors that approach the theoretical maximum of 100%. Both sets of novel designs achieved large fill factors by employing architectures in which some, or all of the photodiode structure was elevated above the plane of the pixel addressing transistor. Generally, enhancement of the fill factor in either discrete or continuous

  12. Active-Matrix Organic Light Emission Diode Pixel Circuit for Suppressing and Compensating for the Threshold Voltage Degradation of Hydrogenated Amorphous Silicon Thin Film Transistors

    NASA Astrophysics Data System (ADS)

    Shin, Hee-Sun; Lee, Won-Kyu; Park, Sang-Guen; Kuk, Seung-Hee; Han, Min-Koo

    2009-03-01

    A new hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) pixel circuit for active-matrix organic light emission diodes (AM-OLEDs), which significantly compensates the OLED current degradation by memorizing the threshold voltage of driving TFT and suppresses the threshold voltage shift of a-Si:H TFTs by negative bias annealing, is proposed and fabricated. During the first half of each frame, the driving TFT of the proposed pixel circuit supplies current to the OLED, which is determined by modified data voltage in the compensation scheme. The proposed pixel circuit was able to compensate the threshold voltage shift of the driving TFT as well as the OLED. During the remaining half of each frame, the proposed pixel circuit induces the recovery of the threshold voltage degradation of a-Si:H TFTs owing to the negative bias annealing. The experimental results show that the proposed pixel circuit was able to successfully compensate for the OLED current degradation and suppress the threshold voltage degradation of the driving TFT.

  13. Amorphous In-Ga-Zn-O Thin Film Transistor Current-Scaling Pixel Electrode Circuit for Active-Matrix Organic Light-Emitting Displays

    NASA Astrophysics Data System (ADS)

    Chen, Charlene; Abe, Katsumi; Fung, Tze-Ching; Kumomi, Hideya; Kanicki, Jerzy

    2009-03-01

    In this paper, we analyze application of amorphous In-Ga-Zn-O thin film transistors (a-InGaZnO TFTs) to current-scaling pixel electrode circuit that could be used for 3-in. quarter video graphics array (QVGA) full color active-matrix organic light-emitting displays (AM-OLEDs). Simulation results, based on a-InGaZnO TFT and OLED experimental data, show that both device sizes and operational voltages can be reduced when compare to the same circuit using hydrogenated amorphous silicon (a-Si:H) TFTs. Moreover, the a-InGaZnO TFT pixel circuit can compensate for the drive TFT threshold voltage variation (ΔVT) within acceptable operating error range.

  14. Source Driver Channel Reduction Schemes Employing Corresponding Pixel Alignments for Current Programming Active-Matrix Organic Light-Emitting Diode Displays

    NASA Astrophysics Data System (ADS)

    Hong, Soon-Kwang; Oh, Du-Hwan; Jeong, Seok-Hee; Park, Young-Ju; Kim, Byeong-Koo; Ha, Yong-Min; Jang, Jin

    2008-03-01

    We propose two types of novel scheme for reducing the number of output channels of driver-integrated circuit (D-IC) for the current programming compensation pixel structures of active-matrix organic light-emitting diodes (AMOLEDs). One is a 2:1 data demultiplexing technique that can reduce the number of output channels of D-IC by half. The proposed second scheme is a vertically aligned red (R), green (G), and blue (B) subpixel scheme instead of a horizontally aligned R-G-B subpixel one, which is regarded as the conventional pixel alignment scheme. We have also successfully implemented these schemes in a 2.4-in.-sized QCIF + (176 × RGB × 220) AMOLED using p-type excimer laser annealing (ELA) low-temperature polycrystalline silicon (LTPS) technology and evaluated key performance characteristics.

  15. Transparent Pixel Circuit with Threshold Voltage Compensation Using ZnO Thin-Film Transistors for Active-Matrix Organic Light Emitting Diode Displays

    NASA Astrophysics Data System (ADS)

    Yang, Ik-Seok; Kwon, Oh-Kyong

    2009-03-01

    A transparent pixel circuit with a threshold voltage compensating scheme using ZnO thin-film transistors (TFTs) for active-matrix organic light emitting diode (AMOLED) displays is proposed. This circuit consists of five n-type ZnO TFTs and two capacitors and can compensate for the threshold voltage variation of ZnO TFTs in real time. From simulation results, the maximum deviation of the emission current of the pixel circuit with a threshold voltage variation of ±1 V is determined to be less than 10 nA. From measurement results, it is verified that the maximum deviation of measured emission currents with measurement position in a glass substrate is less than 15 nA in a higher current range, and the deviation of emission current with time is less than 3%.

  16. Pixel-Level Digital-to-Analog Conversion Scheme with Compensation of Thin-Film-Transistor Variations for Compact Integrated Data Drivers of Active Matrix Organic Light Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Wook; Park, Sang-Gyu; Choi, Byong-Deok

    2011-03-01

    The previous pixel-level digital-to-analog-conversion (DAC) scheme that implements a part of a DAC in a pixel circuit turned out to be very efficient for reducing the peripheral area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs). However, how the pixel-level DAC can be compatible with the existing pixel circuits including compensation schemes of TFT variations and IR drops on supply rails, which is of primary importance for active matrix organic light emitting diodes (AMOLEDs) is an issue in this scheme, because LTPS TFTs suffer from random variations in their characteristics. In this paper, we show that the pixel-level DAC scheme can be successfully used with the previous compensation schemes by giving two examples of voltage- and current-programming pixels. The previous pixel-level DAC schemes require additional two TFTs and one capacitor, but for these newly proposed pixel circuits, the overhead is no more than two TFTs by utilizing the already existing capacitor. In addition, through a detailed analysis, it has been shown that the pixel-level DAC can be expanded to a 4-bit resolution, or be applied together with 1:2 demultiplexing driving for 6- to 8-in. diagonal XGA AMOLED display panels.

  17. Pixel structures to compensate nonuniform threshold voltage and mobility of polycrystalline silicon thin-film transistors using subthreshold current for large-size active matrix organic light-emitting diode displays

    NASA Astrophysics Data System (ADS)

    Na, Jun-Seok; Kwon, Oh-Kyong

    2014-01-01

    We propose pixel structures for large-size and high-resolution active matrix organic light-emitting diode (AMOLED) displays using a polycrystalline silicon (poly-Si) thin-film transistor (TFT) backplane. The proposed pixel structures compensate the variations of the threshold voltage and mobility of the driving TFT using the subthreshold current. The simulated results show that the emission current error of the proposed pixel structure B ranges from -2.25 to 2.02 least significant bit (LSB) when the variations of the threshold voltage and mobility of the driving TFT are ±0.5 V and ±10%, respectively.

  18. Imaging by photon counting with 256x256 pixel matrix

    NASA Astrophysics Data System (ADS)

    Tlustos, Lukas; Campbell, Michael; Heijne, Erik H. M.; Llopart, Xavier

    2004-09-01

    Using 0.25µm standard CMOS we have developed 2-D semiconductor matrix detectors with sophisticated functionality integrated inside each pixel of a hybrid sensor module. One of these sensor modules is a matrix of 256x256 square 55µm pixels intended for X-ray imaging. This device is called 'Medipix2' and features a fast amplifier and two-level discrimination for signals between 1000 and 100000 equivalent electrons, with overall signal noise ~150 e- rms. Signal polarity and comparator thresholds are programmable. A maximum count rate of nearly 1 MHz per pixel can be achieved, which corresponds to an average flux of 3x10exp10 photons per cm2. The selected signals can be accumulated in each pixel in a 13-bit register. The serial readout takes 5-10 ms. A parallel readout of ~300 µs could also be used. Housekeeping functions such as local dark current compensation, test pulse generation, silencing of noisy pixels and threshold tuning in each pixel contribute to the homogeneous response over a large sensor area. The sensor material can be adapted to the energy of the X-rays. Best results have been obtained with high-resistivity silicon detectors, but also CdTe and GaAs detectors have been used. The lowest detectable X-ray energy was about 4 keV. Background measurements have been made, as well as measurements of the uniformity of imaging by photon counting. Very low photon count rates are feasible and noise-free at room temperature. The readout matrix can be used also with visible photons if an energy or charge intensifier structure is interposed such as a gaseous amplification layer or a microchannel plate or acceleration field in vacuum.

  19. Pixel-Level Digital-to-Analog Conversion Scheme for Compact Data Drivers of Active Matrix Organic Light-Emitting Diodes with Low-Temperature Polycrystalline Silicon Thin-Film Transistors

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Wook; Choi, Byong-Deok

    2010-03-01

    This paper shows that a part of a digital-to-analog conversion (DAC) function can be included in a pixel circuit to save the circuit area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). Because the pixel-level DAC can be constructed by two TFTs and one small capacitor, the pixel circuit does not become markedly complex. The design of an 8-bit DAC, which combines a 6-bit resistor-string-based DAC and a 2-bit pixel-level DAC for a 4-in. diagonal VGA format active matrix organic light-emitting diode (AMOLED), is shown in detail. In addition, analysis results are presented, revealing that the 8-bit DAC scheme including a 2-bit pixel-level DAC with 1:3 demultiplexing can be applied to very high video formats, such as XGA, for a 3 to 4-in. diagonal AMOLED. Even for a 9- to 12-in. diagonal AMOLED, the proposed scheme can still be applied to the XGA format, even though no demultiplexing is allowed. The total height of the proposed 8-bit DAC is approximately 960 µm, which is almost one-half of that of the previous 6-bit resistor-string-based DAC.

  20. Pixel-Level Digital-to-Analog Conversion Scheme for Compact Data Drivers of Active Matrix Organic Light-Emitting Diodes with Low-Temperature Polycrystalline Silicon Thin-Film Transistors

    NASA Astrophysics Data System (ADS)

    Tae-Wook Kim,; Byong-Deok Choi,

    2010-03-01

    This paper shows that a part of a digital-to-analog conversion (DAC) function can be included in a pixel circuit to save the circuit area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). Because the pixel-level DAC can be constructed by two TFTs and one small capacitor, the pixel circuit does not become markedly complex. The design of an 8-bit DAC, which combines a 6-bit resistor-string-based DAC and a 2-bit pixel-level DAC for a 4-in. diagonal VGA format active matrix organic light-emitting diode (AMOLED), is shown in detail. In addition, analysis results are presented, revealing that the 8-bit DAC scheme including a 2-bit pixel-level DAC with 1:3 demultiplexing can be applied to very high video formats, such as XGA, for a 3 to 4-in. diagonal AMOLED. Even for a 9- to 12-in. diagonal AMOLED, the proposed scheme can still be applied to the XGA format, even though no demultiplexing is allowed. The total height of the proposed 8-bit DAC is approximately 960 μm, which is almost one-half of that of the previous 6-bit resistor-string-based DAC.

  1. Active Pixel Sensors: Are CCD's Dinosaurs?

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.

    1993-01-01

    Charge-coupled devices (CCD's) are presently the technology of choice for most imaging applications. In the 23 years since their invention in 1970, they have evolved to a sophisticated level of performance. However, as with all technologies, we can be certain that they will be supplanted someday. In this paper, the Active Pixel Sensor (APS) technology is explored as a possible successor to the CCD. An active pixel is defined as a detector array technology that has at least one active transistor within the pixel unit cell. The APS eliminates the need for nearly perfect charge transfer -- the Achilles' heel of CCDs. This perfect charge transfer makes CCD's radiation 'soft,' difficult to use under low light conditions, difficult to manufacture in large array sizes, difficult to integrate with on-chip electronics, difficult to use at low temperatures, difficult to use at high frame rates, and difficult to manufacture in non-silicon materials that extend wavelength response.

  2. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    2004-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  3. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    2003-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  4. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    1995-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  5. Active pixel sensor array with electronic shuttering

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor)

    2002-01-01

    An active pixel cell includes electronic shuttering capability. The cell can be shuttered to prevent additional charge accumulation. One mode transfers the current charge to a storage node that is blocked against accumulation of optical radiation. The charge is sampled from a floating node. Since the charge is stored, the node can be sampled at the beginning and the end of every cycle. Another aspect allows charge to spill out of the well whenever the charge amount gets higher than some amount, thereby providing anti blooming.

  6. CMOS Active Pixel Sensor Technology and Reliability Characterization Methodology

    NASA Technical Reports Server (NTRS)

    Chen, Yuan; Guertin, Steven M.; Pain, Bedabrata; Kayaii, Sammy

    2006-01-01

    This paper describes the technology, design features and reliability characterization methodology of a CMOS Active Pixel Sensor. Both overall chip reliability and pixel reliability are projected for the imagers.

  7. Geometrical modulation transfer function for different pixel active area shapes

    NASA Astrophysics Data System (ADS)

    Yadid-Pecht, Orly

    2000-04-01

    In this work we consider the effect of the pixel active area geometrical shape on the modulation transfer function (MTF) of an image sensor. When designing a CMOS Active Pixel Sensor, or a CCD or CID sensor for this matter, the active area of the pixel would have a certain geometrical shape which might not cover the whole pixel area. To improve the device performance, it is important to understand the effect this has on the pixel sensitivity and on the resulting MTF. We perform a theoretical analysis of the MTF for the active area shape and derive explicit formulas for the transfer function for pixel arrays with a square, a rectangular and an L shaped active area (most commonly used), and generalize for any connected active area shape. Preliminary experimental results of subpixel scanning sensitivity maps and the corresponding MTFs have also bee obtained, which confirm the theoretical derivations. Both the simulation results and the MTF calculated from the point spread function measurements of the actual pixel arrays show that the active area shape contributes significantly to the behavior of the overall MTF. The results also indicate that for any potential pixel active area shape, the effect of its diversion from the square pixel could be calculated, so that tradeoff between the conflicting requirements, such as SNR and MTF, could be compared per each pixel design for better overall sensor performance.

  8. Active-Pixel Cosmic-Ray Sensor

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.; Cunningham, Thomas J.; Holtzman, Melinda J.

    1994-01-01

    Cosmic-ray sensor comprises planar rectangular array of lateral bipolar npn floating-base transistors each of which defines pixel. Collector contacts of all transistors in each row connected to same X (column) line conductor; emitter contacts of all transistors in each column connected to same Y (row) line conductor; and current in each row and column line sensed by amplifier, output of which fed to signal-processing circuits.

  9. Active pixel imagers incorporating pixel-level amplifiers based on polycrystalline-silicon thin-film transistors.

    PubMed

    El-Mohri, Youcef; Antonuk, Larry E; Koniczek, Martin; Zhao, Qihua; Li, Yixin; Street, Robert A; Lu, Jeng-Ping

    2009-07-01

    Active matrix, flat-panel imagers (AMFPIs) employing a 2D matrix of a-Si addressing TFTs have become ubiquitous in many x-ray imaging applications due to their numerous advantages. However, under conditions of low exposures and/or high spatial resolution, their signal-to-noise performance is constrained by the modest system gain relative to the electronic additive noise. In this article, a strategy for overcoming this limitation through the incorporation of in-pixel amplification circuits, referred to as active pixel (AP) architectures, using polycrystalline-silicon (poly-Si) TFTs is reported. Compared to a-Si, poly-Si offers substantially higher mobilities, enabling higher TFT currents and the possibility of sophisticated AP designs based on both n- and p-channel TFTs. Three prototype indirect detection arrays employing poly-Si TFTs and a continuous a-Si photodiode structure were characterized. The prototypes consist of an array (PSI-1) that employs a pixel architecture with a single TFT, as well as two arrays (PSI-2 and PSI-3) that employ AP architectures based on three and five TFTs, respectively. While PSI-1 serves as a reference with a design similar to that of conventional AMFPI arrays, PSI-2 and PSI-3 incorporate additional in-pixel amplification circuitry. Compared to PSI-1, results of x-ray sensitivity demonstrate signal gains of approximately 10.7 and 20.9 for PSI-2 and PSI-3, respectively. These values are in reasonable agreement with design expectations, demonstrating that poly-Si AP circuits can be tailored to provide a desired level of signal gain. PSI-2 exhibits the same high levels of charge trapping as those observed for PSI-1 and other conventional arrays employing a continuous photodiode structure. For PSI-3, charge trapping was found to be significantly lower and largely independent of the bias voltage applied across the photodiode. MTF results indicate that the use of a continuous photodiode structure in PSI-1, PSI-2, and PSI-3 results in

  10. Active pixel imagers incorporating pixel-level amplifiers based on polycrystalline-silicon thin-film transistors

    SciTech Connect

    El-Mohri, Youcef; Antonuk, Larry E.; Koniczek, Martin; Zhao Qihua; Li Yixin; Street, Robert A.; Lu Jengping

    2009-07-15

    Active matrix, flat-panel imagers (AMFPIs) employing a 2D matrix of a-Si addressing TFTs have become ubiquitous in many x-ray imaging applications due to their numerous advantages. However, under conditions of low exposures and/or high spatial resolution, their signal-to-noise performance is constrained by the modest system gain relative to the electronic additive noise. In this article, a strategy for overcoming this limitation through the incorporation of in-pixel amplification circuits, referred to as active pixel (AP) architectures, using polycrystalline-silicon (poly-Si) TFTs is reported. Compared to a-Si, poly-Si offers substantially higher mobilities, enabling higher TFT currents and the possibility of sophisticated AP designs based on both n- and p-channel TFTs. Three prototype indirect detection arrays employing poly-Si TFTs and a continuous a-Si photodiode structure were characterized. The prototypes consist of an array (PSI-1) that employs a pixel architecture with a single TFT, as well as two arrays (PSI-2 and PSI-3) that employ AP architectures based on three and five TFTs, respectively. While PSI-1 serves as a reference with a design similar to that of conventional AMFPI arrays, PSI-2 and PSI-3 incorporate additional in-pixel amplification circuitry. Compared to PSI-1, results of x-ray sensitivity demonstrate signal gains of {approx}10.7 and 20.9 for PSI-2 and PSI-3, respectively. These values are in reasonable agreement with design expectations, demonstrating that poly-Si AP circuits can be tailored to provide a desired level of signal gain. PSI-2 exhibits the same high levels of charge trapping as those observed for PSI-1 and other conventional arrays employing a continuous photodiode structure. For PSI-3, charge trapping was found to be significantly lower and largely independent of the bias voltage applied across the photodiode. MTF results indicate that the use of a continuous photodiode structure in PSI-1, PSI-2, and PSI-3 results in optical

  11. Active pixel imagers incorporating pixel-level amplifiers based on polycrystalline-silicon thin-film transistors

    PubMed Central

    El-Mohri, Youcef; Antonuk, Larry E.; Koniczek, Martin; Zhao, Qihua; Li, Yixin; Street, Robert A.; Lu, Jeng-Ping

    2009-01-01

    Active matrix, flat-panel imagers (AMFPIs) employing a 2D matrix of a-Si addressing TFTs have become ubiquitous in many x-ray imaging applications due to their numerous advantages. However, under conditions of low exposures and∕or high spatial resolution, their signal-to-noise performance is constrained by the modest system gain relative to the electronic additive noise. In this article, a strategy for overcoming this limitation through the incorporation of in-pixel amplification circuits, referred to as active pixel (AP) architectures, using polycrystalline-silicon (poly-Si) TFTs is reported. Compared to a-Si, poly-Si offers substantially higher mobilities, enabling higher TFT currents and the possibility of sophisticated AP designs based on both n- and p-channel TFTs. Three prototype indirect detection arrays employing poly-Si TFTs and a continuous a-Si photodiode structure were characterized. The prototypes consist of an array (PSI-1) that employs a pixel architecture with a single TFT, as well as two arrays (PSI-2 and PSI-3) that employ AP architectures based on three and five TFTs, respectively. While PSI-1 serves as a reference with a design similar to that of conventional AMFPI arrays, PSI-2 and PSI-3 incorporate additional in-pixel amplification circuitry. Compared to PSI-1, results of x-ray sensitivity demonstrate signal gains of ∼10.7 and 20.9 for PSI-2 and PSI-3, respectively. These values are in reasonable agreement with design expectations, demonstrating that poly-Si AP circuits can be tailored to provide a desired level of signal gain. PSI-2 exhibits the same high levels of charge trapping as those observed for PSI-1 and other conventional arrays employing a continuous photodiode structure. For PSI-3, charge trapping was found to be significantly lower and largely independent of the bias voltage applied across the photodiode. MTF results indicate that the use of a continuous photodiode structure in PSI-1, PSI-2, and PSI-3 results in optical fill

  12. Using an Active Pixel Sensor In A Vertex Detector

    SciTech Connect

    Matis, Howard S.; Bieser, Fred; Chen, Yandong; Gareus, Robin; Kleinfelder, Stuart; Oldenburg, Markus; Retiere, Fabrice; Ritter, HansGeorg; Wieman, Howard H.; Wurzel, Samuel E.; Yamamoto, Eugene

    2004-04-22

    Research has shown that Active Pixel CMOS sensors can detect charged particles. We have been studying whether this process can be used in a collider environment. In particular, we studied the effect of radiation with 55 MeV protons. These results show that a fluence of about 2 x 10{sup 12} protons/cm{sup 2} reduces the signal by a factor of two while the noise increases by 25%. A measurement 6 months after exposure shows that the silicon lattice naturally repairs itself. Heating the silicon to 100 C reduced the shot noise and increased the collected charge. CMOS sensors have a reduced signal to noise ratio per pixel because charge diffuses to neighboring pixels. We have constructed a photogate to see if this structure can collect more charge per pixel. Results show that a photogate does collect charge in fewer pixels, but it takes about 15 ms to collect all of the electrons produced by a pulse of light.

  13. Active pixel sensors with substantially planarized color filtering elements

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Kemeny, Sabrina E. (Inventor)

    1999-01-01

    A semiconductor imaging system preferably having an active pixel sensor array compatible with a CMOS fabrication process. Color-filtering elements such as polymer filters and wavelength-converting phosphors can be integrated with the image sensor.

  14. Active pixel sensor array with multiresolution readout

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Kemeny, Sabrina E. (Inventor); Pain, Bedabrata (Inventor)

    1999-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node. There is also a readout circuit, part of which can be disposed at the bottom of each column of cells and be common to all the cells in the column. The imaging device can also include an electronic shutter formed on the substrate adjacent the photogate, and/or a storage section to allow for simultaneous integration. In addition, the imaging device can include a multiresolution imaging circuit to provide images of varying resolution. The multiresolution circuit could also be employed in an array where the photosensitive portion of each pixel cell is a photodiode. This latter embodiment could further be modified to facilitate low light imaging.

  15. Pixel response function experimental techniques and analysis of active pixel sensor star cameras

    NASA Astrophysics Data System (ADS)

    Fumo, Patrick; Waldron, Erik; Laine, Juha-Pekka; Evans, Gary

    2015-04-01

    The pixel response function (PRF) of a pixel within a focal plane is defined as the pixel intensity with respect to the position of a point source within the pixel. One of its main applications is in the field of astrometry, which is a branch of astronomy that deals with positioning data of a celestial body for tracking movement or adjusting the attitude of a spacecraft. Complementary metal oxide semiconductor (CMOS) image sensors generally offer better radiation tolerance to protons and heavy ions than CCDs making them ideal candidates for space applications aboard satellites, but like all image sensors they are limited by their spatial frequency response, better known as the modulation transfer function. Having a well-calibrated PRF allows us to eliminate some of the uncertainty in the spatial response of the system providing better resolution and a more accurate centroid estimation. This paper describes the experimental setup for determining the PRF of a CMOS image sensor and analyzes the effect on the oversampled point spread function (PSF) of an image intensifier, as well as the effects due to the wavelength of light used as a point source. It was found that using electron bombarded active pixel sensor (EBAPS) intensification technology had a significant impact on the PRF of the camera being tested as a result of an increase in the amount of carrier diffusion between collection sites generated by the intensification process. Taking the full width at half maximum (FWHM) of the resulting data, it was found that the intensified version of a CMOS camera exhibited a PSF roughly 16.42% larger than its nonintensified counterpart.

  16. CMOS Active Pixel Sensor (APS) Imager for Scientific Applications

    NASA Astrophysics Data System (ADS)

    Ay, Suat U.; Lesser, Michael P.; Fossum, Eric R.

    2002-12-01

    A 512×512 CMOS Active Pixel Sensor (APS) imager has been designed, fabricate, and tested for frontside illumination suitable for use in astronomy specifically in telescope guider systems as a replacement of CCD chips. The imager features a high-speed differential analog readout, 15 μm pixel pitch, 75 % fill factor (FF), 62 dB dynamic range, 315Ke- pixel capacity, less than 0.25% fixed pattern noise (FPN), 45 dB signal to noise ratio (SNR) and frame rate of up to 40 FPS. Design was implemented in a standard 0.5 μm CMOS process technology consuming less than 200mWatts on a single 5 Volt power supply. CMOS Active Pixel Sensor (APS) imager was developed with pixel structure suitable for both frontside and backside illumination holding large number of electron in relatively small pixel pitch of 15 μm. High-speed readout and signal processing circuits were designed to achieve low fixed pattern noise (FPN) and non-uniformity to provide CCD-like analog outputs. Target spectrum range of operation for the imager is in near ultraviolet (300-400 nm) with high quantum efficiency. This device is going to be used as a test vehicle to develop backside-thinning process.

  17. Matrix light and pixel light: optical system architecture and requirements to the light source

    NASA Astrophysics Data System (ADS)

    Spinger, Benno; Timinger, Andreas L.

    2015-09-01

    Modern Automotive headlamps enable improved functionality for more driving comfort and safety. Matrix or Pixel light headlamps are not restricted to either pure low beam functionality or pure high beam. Light in direction of oncoming traffic is selectively switched of, potential hazard can be marked via an isolated beam and the illumination on the road can even follow a bend. The optical architectures that enable these advanced functionalities are diverse. Electromechanical shutters and lens units moved by electric motors were the first ways to realize these systems. Switching multiple LED light sources is a more elegant and mechanically robust solution. While many basic functionalities can already be realized with a limited number of LEDs, an increasing number of pixels will lead to more driving comfort and better visibility. The required optical system needs not only to generate a desired beam distribution with a high angular dynamic, but also needs to guarantee minimal stray light and cross talk between the different pixels. The direct projection of the LED array via a lens is a simple but not very efficient optical system. We discuss different optical elements for pre-collimating the light with minimal cross talk and improved contrast between neighboring pixels. Depending on the selected optical system, we derive the basic light source requirements: luminance, surface area, contrast, flux and color homogeneity.

  18. Preliminary investigations of active pixel sensors in Nuclear Medicine imaging

    NASA Astrophysics Data System (ADS)

    Ott, Robert; Evans, Noel; Evans, Phil; Osmond, J.; Clark, A.; Turchetta, R.

    2009-06-01

    Three CMOS active pixel sensors have been investigated for their application to Nuclear Medicine imaging. Startracker with 525×525 25 μm square pixels has been coupled via a fibre optic stud to a 2 mm thick segmented CsI(Tl) crystal. Imaging tests were performed using 99mTc sources, which emit 140 keV gamma rays. The system was interfaced to a PC via FPGA-based DAQ and optical link enabling imaging rates of 10 f/s. System noise was measured to be >100e and it was shown that the majority of this noise was fixed pattern in nature. The intrinsic spatial resolution was measured to be ˜80 μm and the system spatial resolution measured with a slit was ˜450 μm. The second sensor, On Pixel Intelligent CMOS (OPIC), had 64×72 40 μm pixels and was used to evaluate noise characteristics and to develop a method of differentiation between fixed pattern and statistical noise. The third sensor, Vanilla, had 520×520 25 μm pixels and a measured system noise of ˜25e. This sensor was coupled directly to the segmented phosphor. Imaging results show that even at this lower level of noise the signal from 140 keV gamma rays is small as the light from the phosphor is spread over a large number of pixels. Suggestions for the 'ideal' sensor are made.

  19. ALPIDE, the Monolithic Active Pixel Sensor for the ALICE ITS upgrade

    NASA Astrophysics Data System (ADS)

    Mager, M.

    2016-07-01

    A new 10 m2 inner tracking system based on seven concentric layers of Monolithic Active Pixel Sensors will be installed in the ALICE experiment during the second long shutdown of LHC in 2019-2020. The monolithic pixel sensors will be fabricated in the 180 nm CMOS Imaging Sensor process of TowerJazz. The ALPIDE design takes full advantage of a particular process feature, the deep p-well, which allows for full CMOS circuitry within the pixel matrix, while at the same time retaining the full charge collection efficiency. Together with the small feature size and the availability of six metal layers, this allowed a continuously active low-power front-end to be placed into each pixel and an in-matrix sparsification circuit to be used that sends only the addresses of hit pixels to the periphery. This approach led to a power consumption of less than 40 mWcm-2, a spatial resolution of around 5 μm, a peaking time of around 2 μs, while being radiation hard to some 1013 1 MeVneq /cm2, fulfilling or exceeding the ALICE requirements. Over the last years of R & D, several prototype circuits have been used to verify radiation hardness, and to optimize pixel geometry and in-pixel front-end circuitry. The positive results led to a submission of full-scale (3 cm×1.5 cm) sensor prototypes in 2014. They are being characterized in a comprehensive campaign that also involves several irradiation and beam tests. A summary of the results obtained and prospects towards the final sensor to instrument the ALICE Inner Tracking System are given.

  20. Fabrication of LED full-color display matrix with small pixel

    NASA Astrophysics Data System (ADS)

    Li, Jing; Xue, Bin; Yang, Hua; Liu, Lili; Xie, Haizhong; Pei, Yanrong; Lu, Pengzhi; Wang, Guohong; Wang, Junxi; Li, Jinmin

    2015-09-01

    With the development in material growth, device fabrication and packaging of LEDs, emission spectral of LED is able to cover the visible spectrum. In addition to the well-known lighting applications of LED, display is also one of the important applications of LED. In contrast with LCD, LEDs display has better contrast ratio, higher response rate, etc., which makes LEDs along with other self-illumination technologies an ideal candidate in making display panel. With the popularization of HD and Ultra HD standard, display panel with better image quality is needed. The number of pixels of the panel needs to be increased and the size of each pixel needs to be minimized. In this paper, we prepared a LED full-color display panel based on a 32×32 LED matrix with typical pixel size of 0.5mm. LED full-color display array with small pixel was obtained by mounting red LEDs, green LEDs and blue LEDs directly onto an isolating substrate such as sapphire . In addition, the substrate has metalized pads and connection before the matrix was connected to control unit. The control line and the column data line are prepared on the substrate, and there is an effective electrical insulation layers between them. The isolation layers consists of a SiO2 layer of 1000nm and polyimide layer of 3000nm. Polyimide as an important electrical insulating layer, we study some properties of it, such as :PI amination rate as a function of the curing temperature, PI resistivity as a function of the curing temperature and the punction electric field intensity of PI as a function of the film thickness of PI.

  1. CMOS VLSI Active-Pixel Sensor for Tracking

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata; Sun, Chao; Yang, Guang; Heynssens, Julie

    2004-01-01

    An architecture for a proposed active-pixel sensor (APS) and a design to implement the architecture in a complementary metal oxide semiconductor (CMOS) very-large-scale integrated (VLSI) circuit provide for some advanced features that are expected to be especially desirable for tracking pointlike features of stars. The architecture would also make this APS suitable for robotic- vision and general pointing and tracking applications. CMOS imagers in general are well suited for pointing and tracking because they can be configured for random access to selected pixels and to provide readout from windows of interest within their fields of view. However, until now, the architectures of CMOS imagers have not supported multiwindow operation or low-noise data collection. Moreover, smearing and motion artifacts in collected images have made prior CMOS imagers unsuitable for tracking applications. The proposed CMOS imager (see figure) would include an array of 1,024 by 1,024 pixels containing high-performance photodiode-based APS circuitry. The pixel pitch would be 9 m. The operations of the pixel circuits would be sequenced and otherwise controlled by an on-chip timing and control block, which would enable the collection of image data, during a single frame period, from either the full frame (that is, all 1,024 1,024 pixels) or from within as many as 8 different arbitrarily placed windows as large as 8 by 8 pixels each. A typical prior CMOS APS operates in a row-at-a-time ( grolling-shutter h) readout mode, which gives rise to exposure skew. In contrast, the proposed APS would operate in a sample-first/readlater mode, suppressing rolling-shutter effects. In this mode, the analog readout signals from the pixels corresponding to the windows of the interest (which windows, in the star-tracking application, would presumably contain guide stars) would be sampled rapidly by routing them through a programmable diagonal switch array to an on-chip parallel analog memory array. The

  2. Transversal-readout CMOS active pixel image sensor

    NASA Astrophysics Data System (ADS)

    Miyatake, Shigehiro; Ishida, Kouichi; Morimoto, Takashi; Masaki, Yasuo; Tanabe, Hideki

    2001-05-01

    This paper presents a CMOS active pixel image sensor (APS) with a transversal readout architecture that eliminates the vertically striped fixed pattern noise (FPN). There are two kinds of FPNs for CMOS APSs. One originates form the pixel- to-pixel variation in dark current and source-follower threshold voltage, and the other from the column-to-column variation in column readout structures. The former may become invisible in the future due to process improvements. However, the latter, which result sin a vertically striped FPN, is and will be conspicuous without some subtraction because of the correlation in the vertical direction. The pixel consists of a photodiode, a row- and a column-reset transistor, a source follower input transistor, and a column-select transistor instead of the row-select transistor in conventional CMOS APSs. The column-select transistor is connected to a signal line, which runs horizontally instead of vertically. Every horizontal signal line is merged into a single vertical signal line via a row- select transistor, which can be made large enough to make its on-resistence variation negligible because of its low driving frequency. Therefore, the sensor has neither a vertical nor horizontal stripe FPN.

  3. Monolithic active pixel sensors (MAPS) in a VLSI CMOS technology

    NASA Astrophysics Data System (ADS)

    Turchetta, R.; French, M.; Manolopoulos, S.; Tyndel, M.; Allport, P.; Bates, R.; O'Shea, V.; Hall, G.; Raymond, M.

    2003-03-01

    Monolithic Active Pixel Sensors (MAPS) designed in a standard VLSI CMOS technology have recently been proposed as a compact pixel detector for the detection of high-energy charged particle in vertex/tracking applications. MAPS, also named CMOS sensors, are already extensively used in visible light applications. With respect to other competing imaging technologies, CMOS sensors have several potential advantages in terms of low cost, low power, lower noise at higher speed, random access of pixels which allows windowing of region of interest, ability to integrate several functions on the same chip. This brings altogether to the concept of 'camera-on-a-chip'. In this paper, we review the use of CMOS sensors for particle physics and we analyse their performances in term of the efficiency (fill factor), signal generation, noise, readout speed and sensor area. In most of high-energy physics applications, data reduction is needed in the sensor at an early stage of the data processing before transfer of the data to tape. Because of the large number of pixels, data reduction is needed on the sensor itself or just outside. This brings in stringent requirements on the temporal noise as well as to the sensor uniformity, expressed as a Fixed Pattern Noise (FPN). A pixel architecture with an additional transistor is proposed. This architecture, coupled to correlated double sampling of the signal will allow cancellation of the two dominant noise sources, namely the reset or kTC noise and the FPN. A prototype has been designed in a standard 0.25 μm CMOS technology. It has also a structure for electrical calibration of the sensor. The prototype is functional and detailed tests are under way.

  4. Bonding techniques for hybrid active pixel sensors (HAPS)

    NASA Astrophysics Data System (ADS)

    Bigas, M.; Cabruja, E.; Lozano, M.

    2007-05-01

    A hybrid active pixel sensor (HAPS) consists of an array of sensing elements which is connected to an electronic read-out unit. The most used way to connect these two different devices is bump bonding. This interconnection technique is very suitable for these systems because it allows a very fine pitch and a high number of I/Os. However, there are other interconnection techniques available such as direct bonding. This paper, as a continuation of a review [M. Lozano, E. Cabruja, A. Collado, J. Santander, M. Ullan, Nucl. Instr. and Meth. A 473 (1-2) (2001) 95-101] published in 2001, presents an update of the different advanced bonding techniques available for manufacturing a hybrid active pixel detector.

  5. 3D monolithically stacked CMOS Active Pixel Sensors for particle position and direction measurements

    NASA Astrophysics Data System (ADS)

    Servoli, L.; Passeri, D.; Morozzi, A.; Magalotti, D.; Piperku, L.

    2015-01-01

    In this work we propose a 3D monolithically stacked, multi-layer detectors based on CMOS Active Pixel Sensors (APS) layers which allows at the same time accurate estimation of the impact point and of the incidence angle an ionizing particle. The whole system features two fully-functional CMOS APS matrix detectors, including both sensing area and control/signal elaboration circuitry, stacked in a monolithic device by means of Through Silicon Via (TSV) connections thanks to the capabilities of the CMOS vertical scale integration (3D-IC) 130 nm Chartered/Tezzaron technology. In order to evaluate the suitability of the two layer monolithic active pixel sensor system to reconstruct particle tracks, tests with proton beams have been carried out at the INFN LABEC laboratories in Florence (Italy) with 3 MeV proton beam.

  6. Active pixel sensor pixel having a photodetector whose output is coupled to an output transistor gate

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Nakamura, Junichi (Inventor); Kemeny, Sabrina E. (Inventor)

    2005-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node. There is also a readout circuit, part of which can be disposed at the bottom of each column of cells and be common to all the cells in the column. A Simple Floating Gate (SFG) pixel structure could also be employed in the imager to provide a non-destructive readout and smaller pixel sizes.

  7. A CMOS Active Pixel Sensor for Charged Particle Detection

    SciTech Connect

    Matis, Howard S.; Bieser, Fred; Kleinfelder, Stuart; Rai, Gulshan; Retiere, Fabrice; Ritter, Hans George; Singh, Kunal; Wurzel, Samuel E.; Wieman, Howard; Yamamoto, Eugene

    2002-12-02

    Active Pixel Sensor (APS) technology has shown promise for next-generation vertex detectors. This paper discusses the design and testing of two generations of APS chips. Both are arrays of 128 by 128 pixels, each 20 by 20 {micro}m. Each array is divided into sub-arrays in which different sensor structures (4 in the first version and 16 in the second) and/or readout circuits are employed. Measurements of several of these structures under Fe{sup 55} exposure are reported. The sensors have also been irradiated by 55 MeV protons to test for radiation damage. The radiation increased the noise and reduced the signal. The noise can be explained by shot noise from the increased leakage current and the reduction in signal is due to charge being trapped in the epi layer. Nevertheless, the radiation effect is small for the expected exposures at RHIC and RHIC II. Finally, we describe our concept for mechanically supporting a thin silicon wafer in an actual detector.

  8. Evaluation of a single-pixel one-transistor active pixel sensor for fingerprint imaging

    NASA Astrophysics Data System (ADS)

    Xu, Man; Ou, Hai; Chen, Jun; Wang, Kai

    2015-08-01

    Since it first appeared in iPhone 5S in 2013, fingerprint identification (ID) has rapidly gained popularity among consumers. Current fingerprint-enabled smartphones unanimously consists of a discrete sensor to perform fingerprint ID. This architecture not only incurs higher material and manufacturing cost, but also provides only static identification and limited authentication. Hence as the demand for a thinner, lighter, and more secure handset grows, we propose a novel pixel architecture that is a photosensitive device embedded in a display pixel and detects the reflected light from the finger touch for high resolution, high fidelity and dynamic biometrics. To this purpose, an amorphous silicon (a-Si:H) dual-gate photo TFT working in both fingerprint-imaging mode and display-driving mode will be developed.

  9. CMOS Monolithic Active Pixel Sensors (MAPS): Developments and future outlook

    NASA Astrophysics Data System (ADS)

    Turchetta, R.; Fant, A.; Gasiorek, P.; Esbrand, C.; Griffiths, J. A.; Metaxas, M. G.; Royle, G. J.; Speller, R.; Venanzi, C.; van der Stelt, P. F.; Verheij, H.; Li, G.; Theodoridis, S.; Georgiou, H.; Cavouras, D.; Hall, G.; Noy, M.; Jones, J.; Leaver, J.; Machin, D.; Greenwood, S.; Khaleeq, M.; Schulerud, H.; Østby, J. M.; Triantis, F.; Asimidis, A.; Bolanakis, D.; Manthos, N.; Longo, R.; Bergamaschi, A.

    2007-12-01

    Re-invented in the early 1990s, on both sides of the Atlantic, Monolithic Active Pixel Sensors (MAPS) in a CMOS technology are today the most sold solid-state imaging devices, overtaking the traditional technology of Charge-Coupled Devices (CCD). The slow uptake of CMOS MAPS started with low-end applications, for example web-cams, and is slowly pervading the high-end applications, for example in prosumer digital cameras. Higher specifications are required for scientific applications: very low noise, high speed, high dynamic range, large format and radiation hardness are some of these requirements. This paper will present a brief overview of the CMOS Image Sensor technology and of the requirements for scientific applications. As an example, a sensor for X-ray imaging will be presented. This sensor was developed within a European FP6 Consortium, intelligent imaging sensors (I-ImaS).

  10. Monolithic active pixel radiation detector with shielding techniques

    DOEpatents

    Deptuch, Grzegorz W.

    2016-09-06

    A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

  11. Active pixel sensor having intra-pixel charge transfer with analog-to-digital converter

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra K. (Inventor); Pain, Bedabrata (Inventor); Nixon, Robert H. (Inventor); Zhou, Zhimin (Inventor)

    2003-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node and an analog-to-digital converter formed in the substrate connected to the output of the readout circuit.

  12. Active pixel sensor having intra-pixel charge transfer with analog-to-digital converter

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra K. (Inventor); Pain, Bedabrata (Inventor); Nixon, Robert H. (Inventor); Zhou, Zhimin (Inventor)

    2000-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor Integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node and an analog-to-digital converter formed in the substrate connected to the output of the readout circuit.

  13. 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.

  14. Thin film transistor circuits for active matrix liquid crystal displays

    NASA Astrophysics Data System (ADS)

    Edwards, Martin John

    The demand for a high quality flat panel video display device for use in consumer and professional products has led to the rapid development of Active Matrix Liquid Crystal Displays (AMLCD). The majority of these displays use Thin Film Transistors (TFTs) as the active devices and improvements in the performance of these transistors is creating the opportunity to integrate increasingly sophisticated circuits onto the glass substrates of the displays. This thesis describes a number of aspects of the use of thin film transistor circuits for active matrix liquid crystal displays. The electrical characteristics of TFTs differ in a number of respects from those of conventional MOS devices. This is illustrated with measurements of transistors and simple circuits fabricated using two different low temperature poly-Si TFT technologies. At present the key application for TFT circuits is integration of the row and column drive circuits for active matrix liquid crystal displays. The issues which arise in the design of TFT drive circuits are discussed and the design and operation of a prototype display with integrated drive circuits is described. The availability of high mobility TFTs makes it possible to integrate signal processing functions within the pixels of a display. A novel technique employing digital to analogue conversion of the video data within the pixels of a display is presented. This technique allows the display to be addressed with digital column drive waveforms simplifying the column drive circuit. Operation of the pixel data converters has been demonstrated by the design and measurement of small arrays of test pixels.

  15. Characteristics of Monolithically Integrated InGaAs Active Pixel Image Array

    NASA Technical Reports Server (NTRS)

    Kim, Q.; Cunningham, T. J.; Pain, B.; Lange, M. J.; Olsen, G. H.

    1999-01-01

    Switching and amplifying characteristics of a newly developed monolithic InGaAs Active Pixel Imager Array are presented. The sensor array is fabricated from InGaAs material epitaxially deposited on an InP substrate.

  16. Center of mass detection via an active pixel sensor

    NASA Technical Reports Server (NTRS)

    Yadid-Pecht, Orly (Inventor); Minch, Brad (Inventor); Pain, Bedabrata (Inventor); Fossum, Eric (Inventor)

    2002-01-01

    An imaging system for identifying the location of the center of mass (COM) in an image. In one aspect, an imaging system includes a plurality of photosensitive elements arranged in a matrix. A center of mass circuit coupled to the photosensitive elements includes a resistive network and a normalization circuit including at least one bipolar transistor. The center of mass circuit identifies a center of mass location in the matrix and includes: a row circuit, where the row circuit identifies a center of mass row value in each row of the matrix and identifies a row intensity for each row; a horizontal circuit, where the horizontal circuit identifies a center of mass horizontal value; and a vertical circuit, where the vertical circuit identifies a center of mass vertical value. The horizontal and vertical center of mass values indicate the coordinates of the center of mass location for the image.

  17. Center of mass detection via an active pixel sensor

    NASA Technical Reports Server (NTRS)

    Yadid-Pecht, Orly (Inventor); Minch, Brad (Inventor); Pain, Bedabrara (Inventor); Fossum, Eric (Inventor)

    2006-01-01

    An imaging system for identifying the location of the center of mass (COM) in an image. In one aspect, an imaging system includes a plurality of photosensitive elements arranged in a matrix. A center of mass circuit coupled to the photosensitive elements includes a resistive network and a normalization circuit including at least one bipolar transistor. The center of mass circuit identifies a center of mass location in the matrix and includes: a row circuit, where the row circuit identifies a center of mass row value in each row of the matrix and identifies a row intensity for each row; a horizontal circuit, where the horizontal circuit identifies a center of mass horizontal value; and a vertical circuit, where the vertical circuit identifies a center of mass vertical value. The horizontal and vertical center of mass values indicate the coordinates of the center of mass location for the image.

  18. Center of mass detection via an active pixel sensor

    NASA Technical Reports Server (NTRS)

    Yadid-Pecht, Orly (Inventor); Minch, Brad (Inventor); Pain, Bedabrata (Inventor); Fossum, Eric (Inventor)

    2005-01-01

    An imaging system for identifying the location of the center of mass (COM) in an image. In one aspect, an imaging system includes a plurality of photosensitive elements arranged in a matrix. A center of mass circuit coupled to the photosensitive elements includes a resistive network and a normalization circuit including at least one bipolar transistor. The center of mass circuit identifies a center of mass location in the matrix and includes: a row circuit, where the row circuit identifies a center of mass row value in each row of the matrix and identifies a row intensity for each row; a horizontal circuit, where the horizontal circuit identifies a center of mass horizontal value; and a vertical circuit, where the vertical circuit identifies a center of mass vertical value. The horizontal and vertical center of mass values indicate the coordinates of the center of mass location for the image.

  19. Laminated active matrix organic light-emitting devices

    NASA Astrophysics Data System (ADS)

    Liu, Hongyu; Sun, Runguang

    2008-02-01

    Laminated active matrix organic light-emitting device (AMOLED) realizing top emission by using bottom-emitting organic light-emitting diode (OLED) structure was proposed. The multilayer structure of OLED deposited in the conventional sequence is not on the thin film transistor (TFT) backplane but on the OLED plane. The contact between the indium tin oxide (ITO) electrode of TFT backplane and metal cathode of OLED plane is implemented by using transfer electrode. The stringent pixel design for aperture ratio of the bottom-emitting AMOLED, as well as special technology for the top ITO electrode of top-emitting AMOLED, is unnecessary in the laminated AMOLED.

  20. Pixel-level multisensor image fusion based on matrix completion and robust principal component analysis

    NASA Astrophysics Data System (ADS)

    Wang, Zhuozheng; Deller, J. R.; Fleet, Blair D.

    2016-01-01

    Acquired digital images are often corrupted by a lack of camera focus, faulty illumination, or missing data. An algorithm is presented for fusion of multiple corrupted images of a scene using the lifting wavelet transform. The method employs adaptive fusion arithmetic based on matrix completion and self-adaptive regional variance estimation. Characteristics of the wavelet coefficients are used to adaptively select fusion rules. Robust principal component analysis is applied to low-frequency image components, and regional variance estimation is applied to high-frequency components. Experiments reveal that the method is effective for multifocus, visible-light, and infrared image fusion. Compared with traditional algorithms, the new algorithm not only increases the amount of preserved information and clarity but also improves robustness.

  1. Recent progress in the development of a B-factory monolithic active pixel detector

    NASA Astrophysics Data System (ADS)

    Stanič, S.; Aihara, H.; Barbero, M.; Bozek, A.; Browder, T.; Hazumi, M.; Kennedy, J.; Kent, N.; Olsen, S.; Palka, H.; Rosen, M.; Ruckman, L.; Trabelsi, K.; Tsuboyama, T.; Uchida, K.; Varner, G.; Yang, Q.

    2006-11-01

    Due to the need for precise vertexing at future higher luminosity B-factories with the expectedly increasing track densities and radiation exposures, upgrade of present silicon strip detectors with thin, radiation resistant pixel detectors is highly desired. Considerable progress in the technological development of thin CMOS based Monolithic Active Pixel Sensors (MAPS) in the last years makes them a realistic upgrade option and the feasibility studies of their application in Belle are actively pursued. The most serious concerns are their radiation hardness and their read-out speed. To address them, several prototypes denoted as Continuous Acquisition Pixel (CAP) sensors have been developed and tested. The latest of the CAP sensor prototypes is CAP3, designed in the TSMC 0.25 μm process with a 5-deep sample pair pipeline in each pixel. A setup with several CAP3 sensors will be used to assess the performance of a full scale pixel read-out system running at realistic read-out speed. The results and plans for the next stages of R&D towards a full Pixel Vertex Detector (PVD) are presented.

  2. Active Matrix OLED Test Report

    NASA Technical Reports Server (NTRS)

    Salazar, George

    2013-01-01

    This report focuses on the limited environmental testing of the AMOLED display performed as an engineering evaluation by The NASA Johnson Space Center (JSC)-specifically. EMI. Thermal Vac, and radiation tests. The AMOLED display is an active-matrix Organic Light Emitting Diode (OLED) technology. The testing provided an initial understanding of the technology and its suitability for space applications. Relative to light emitting diode (LED) displays or liquid crystal displays (LCDs), AMOLED displays provide a superior viewing experience even though they are much lighter and smaller, produce higher contrast ratio and richer colors, and require less power to operate than LCDs. However, AMOLED technology has not been demonstrated in a space environment. Therefore, some risks with the technology must be addressed before they can be seriously considered for human spaceflight. The environmental tests provided preliminary performance data on the ability of the display technology to handle some of the simulated induced space/spacecraft environments that an AMOLED display will see during a spacecraft certification test program. This engineering evaluation is part of a Space Act Agreement (SM) between The NASA/JSC and Honeywell International (HI) as a collaborative effort to evaluate the potential use of AMOLED technology for future human spaceflight missions- both government-led and commercial. Under this SM, HI is responsible for doing optical performance evaluation, as well as temperature and touch screen studies. The NASA/JSC is responsible for performing environmental testing comprised of EMI, Thermal Vac, and radiation tests. Additionally, as part of the testing, limited optical data was acquired to assess performance as the display was subjected to the induced environments. The NASA will benefit from this engineering evaluation by understanding AMOLED suitability for future use in space as well as becoming a smarter buyer (or developer) of the technology. HI benefits

  3. Heavy Ion Transient Characterization of a Photobit Hardened-by-Design Active Pixel Sensor Array

    NASA Technical Reports Server (NTRS)

    Marshall, Paul W.; Byers, Wheaton B.; Conger, Christopher; Eid, El-Sayed; Gee, George; Jones, Michael R.; Marshall, Cheryl J.; Reed, Robert; Pickel, Jim; Kniffin, Scott

    2002-01-01

    This paper presents heavy ion data on the single event transient (SET) response of a Photobit active pixel sensor (APS) four quadrant test chip with different radiation tolerant designs in a standard 0.35 micron CMOS process. The physical design techniques of enclosed geometry and P-channel guard rings are used to design the four N-type active photodiode pixels as described in a previous paper. Argon transient measurements on the 256 x 256 chip array as a function of incident angle show a significant variation in the amount of charge collected as well as the charge spreading dependent on the pixel type. The results are correlated with processing and design information provided by Photobit. In addition, there is a large degree of statistical variability between individual ion strikes. No latch-up is observed up to an LET of 106 MeV/mg/sq cm.

  4. Characterisation of Vanilla—A novel active pixel sensor for radiation detection

    NASA Astrophysics Data System (ADS)

    Blue, A.; Bates, R.; Laing, A.; Maneuski, D.; O'Shea, V.; Clark, A.; Prydderch, M.; Turchetta, R.; Arvanitis, C.; Bohndiek, S.

    2007-10-01

    Novel features of a new monolithic active pixel sensor, Vanilla, with 520×520 pixels ( 25 μm square) has been characterised for the first time. Optimisation of the sensor operation was made through variation of frame rates, integration times and on-chip biases and voltages. Features such as flushed reset operation, ROI capturing and readout modes have been fully tested. Stability measurements were performed to test its suitablility for long-term applications. These results suggest the Vanilla sensor—along with bio-medical and space applications—is suitable for use in particle physics experiments.

  5. Front end optimization for the monolithic active pixel sensor of the ALICE Inner Tracking System upgrade

    NASA Astrophysics Data System (ADS)

    Kim, D.; Aglieri Rinella, G.; Cavicchioli, C.; Chanlek, N.; Collu, A.; Degerli, Y.; Dorokhov, A.; Flouzat, C.; Gajanana, D.; Gao, C.; Guilloux, F.; Hillemanns, H.; Hristozkov, S.; Junique, A.; Keil, M.; Kofarago, M.; Kugathasan, T.; Kwon, Y.; Lattuca, A.; Mager, M.; Sielewicz, K. M.; Marin Tobon, C. A.; Marras, D.; Martinengo, P.; Mazza, G.; Mugnier, H.; Musa, L.; Pham, T. H.; Puggioni, C.; Reidt, F.; Riedler, P.; Rousset, J.; Siddhanta, S.; Snoeys, W.; Song, M.; Usai, G.; Van Hoorne, J. W.; Yang, P.

    2016-02-01

    ALICE plans to replace its Inner Tracking System during the second long shut down of the LHC in 2019 with a new 10 m2 tracker constructed entirely with monolithic active pixel sensors. The TowerJazz 180 nm CMOS imaging Sensor process has been selected to produce the sensor as it offers a deep pwell allowing full CMOS in-pixel circuitry and different starting materials. First full-scale prototypes have been fabricated and tested. Radiation tolerance has also been verified. In this paper the development of the charge sensitive front end and in particular its optimization for uniformity of charge threshold and time response will be presented.

  6. Interpixel crosstalk in a 3D-integrated active pixel sensor for x-ray detection

    NASA Astrophysics Data System (ADS)

    LaMarr, Beverly; Bautz, Mark; Foster, Rick; Kissel, Steve; Prigozhin, Gregory; Suntharalingam, Vyshnavi

    2010-07-01

    MIT Lincoln Laboratories and MIT Kavli Institute for Astrophysics and Space Research have developed an active pixel sensor for use as a photon counting device for imaging spectroscopy in the soft X-ray band. A silicon-on-insulator (SOI) readout circuit was integrated with a high-resistivity silicon diode detector array using a per-pixel 3D integration technique developed at Lincoln Laboratory. We have tested these devices at 5.9 keV and 1.5 keV. Here we examine the interpixel cross-talk measured with 5.9 keV X-rays.

  7. Autonomous star tracker based on active pixel sensors (APS)

    NASA Astrophysics Data System (ADS)

    Schmidt, U.

    2004-06-01

    Star trackers are opto-electronic sensors used onboard of satellites for the autonomous inertial attitude determination. During the last years, star trackers became more and more important in the field of the attitude and orbit control system (AOCS) sensors. High performance star trackers are based up today on charge coupled device (CCD) optical camera heads. The Jena-Optronik GmbH is active in the field of opto-electronic sensors like star trackers since the early 80-ties. Today, with the product family ASTRO5, ASTRO10 and ASTRO15, all marked segments like earth observation, scientific applications and geo-telecom are supplied to European and Overseas customers. A new generation of star trackers can be designed based on the APS detector technical features. The measurement performance of the current CCD based star trackers can be maintained, the star tracker functionality, reliability and robustness can be increased while the unit costs are saved.

  8. Development of radiation hard CMOS active pixel sensors for HL-LHC

    NASA Astrophysics Data System (ADS)

    Pernegger, Heinz

    2016-07-01

    New pixel detectors, based on commercial high voltage and/or high resistivity full CMOS processes, hold promise as next-generation active pixel sensors for inner and intermediate layers of the upgraded ATLAS tracker. The use of commercial CMOS processes allow cost-effective detector construction and simpler hybridisation techniques. The paper gives an overview of the results obtained on AMS-produced CMOS sensors coupled to the ATLAS Pixel FE-I4 readout chips. The SOI (silicon-on-insulator) produced sensors by XFAB hold great promise as radiation hard SOI-CMOS sensors due to their combination of partially depleted SOI transistors reducing back-gate effects. The test results include pre-/post-irradiation comparison, measurements of charge collection regions as well as test beam results.

  9. [High-Performance Active Pixel X-Ray Sensors for X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Bautz, Mark; Suntharalingam, Vyshnavi

    2005-01-01

    The subject grants support development of High-Performance Active Pixel Sensors for X-ray Astronomy at the Massachusetts Institute of Technology (MIT) Center for Space Research and at MIT's Lincoln Laboratory. This memo reports our progress in the second year of the project, from April, 2004 through the present.

  10. Heavily irradiated N-in-p thin planar pixel sensors with and without active edges

    NASA Astrophysics Data System (ADS)

    Terzo, S.; Andricek, L.; Macchiolo, A.; Moser, H. G.; Nisius, R.; Richter, R. H.; Weigell, P.

    2014-05-01

    We present the results of the characterization of silicon pixel modules employing n-in-p planar sensors with an active thickness of 150 μm, produced at MPP/HLL, and 100-200 μm thin active edge sensor devices, produced at VTT in Finland. These thin sensors are designed as candidates for the ATLAS pixel detector upgrade to be operated at the HL-LHC, as they ensure radiation hardness at high fluences. They are interconnected to the ATLAS FE-I3 and FE-I4 read-out chips. Moreover, the n-in-p technology only requires a single side processing and thereby it is a cost-effective alternative to the n-in-n pixel technology presently employed in the LHC experiments. High precision beam test measurements of the hit efficiency have been performed on these devices both at the CERN SpS and at DESY, Hamburg. We studied the behavior of these sensors at different bias voltages and different beam incident angles up to the maximum one expected for the new Insertable B-Layer of ATLAS and for HL-LHC detectors. Results obtained with 150 μm thin sensors, assembled with the new ATLAS FE-I4 chip and irradiated up to a fluence of 4 × 1015 neq/cm2, show that they are excellent candidates for larger radii of the silicon pixel tracker in the upgrade of the ATLAS detector at HL-LHC. In addition, the active edge technology of the VTT devices maximizes the active area of the sensor and reduces the material budget to suit the requirements for the innermost layers. The edge pixel performance of VTT modules has been investigated at beam test experiments and the analysis after irradiation up to a fluence of 5 × 1015 neq/cm2 has been performed using radioactive sources in the laboratory.

  11. Spectral characterisation and noise performance of Vanilla—an active pixel sensor

    NASA Astrophysics Data System (ADS)

    Blue, Andrew; Bates, R.; Bohndiek, S. E.; Clark, A.; Arvanitis, Costas D.; Greenshaw, T.; Laing, A.; Maneuski, D.; Turchetta, R.; O'Shea, V.

    2008-06-01

    This work will report on the characterisation of a new active pixel sensor, Vanilla. The Vanilla comprises of 512×512 (25μm 2) pixels. The sensor has a 12 bit digital output for full-frame mode, although it can also be readout in analogue mode, whereby it can also be read in a fully programmable region-of-interest (ROI) mode. In full frame, the sensor can operate at a readout rate of more than 100 frames per second (fps), while in ROI mode, the speed depends on the size, shape and number of ROIs. For example, an ROI of 6×6 pixels can be read at 20,000 fps in analogue mode. Using photon transfer curve (PTC) measurements allowed for the calculation of the read noise, shot noise, full-well capacity and camera gain constant of the sensor. Spectral response measurements detailed the quantum efficiency (QE) of the detector through the UV and visible region. Analysis of the ROI readout mode was also performed. Such measurements suggest that the Vanilla APS (active pixel sensor) will be suitable for a wide range of applications including particle physics and medical imaging.

  12. Depleted Monolithic Active Pixel Sensors (DMAPS) implemented in LF-150 nm CMOS technology

    NASA Astrophysics Data System (ADS)

    Kishishita, T.; Hemperek, T.; Krüger, H.; Wermes, N.

    2015-03-01

    We present the recent development of Depleted Monolithic Active Pixel Sensors (DMAPS), implemented with an LFoundry (LF) 150 nm CMOS process. MAPS detectors based on an epi-layer have been matured in recent years and have attractive features in terms of reducing material budget and handling cost compared to conventional hybrid pixel detectors. However, the obtained signal is relatively small (~1000 e-) due to the thin epi-layer, and charge collection time is relatively slow, e.g., in the order of 100 ns, because charges are mainly collected by diffusion. Modern commercial CMOS technology, however, offers advanced process options to overcome such difficulties and enable truly monolithic devices as an alternative to hybrid pixel sensors and charge coupled devices. Unlike in the case of the standard MAPS technologies with epi-layers, the LF process provides a high-resistivity substrate that enables large signal and fast charge collection by drift in a ~50 μm thick depleted layer. Since this process also enables the use of deep n- and p-wells to isolate the collection electrode from the thin active device layer, PMOS and NMOS transistors are available for the readout electronics in each pixel cell. In order to evaluate the sensor and transistor characteristics, several collection electrodes variants and readout architectures have been implemented. In this report, we focus on its design aspect of the LF-DMAPS prototype chip.

  13. ACTIVE-EYES: an adaptive pixel-by-pixel image-segmentation sensor architecture for high-dynamic-range hyperspectral imaging.

    PubMed

    Christensen, Marc P; Euliss, Gary W; McFadden, Michael J; Coyle, Kevin M; Milojkovic, Predrag; Haney, Michael W; van der Gracht, Joeseph; Athale, Ravindra A

    2002-10-10

    The ACTIVE-EYES (adaptive control for thermal imagers via electro-optic elements to yield an enhanced sensor) architecture, an adaptive image-segmentation and processing architecture, based on digital micromirror (DMD) array technology, is described. The concept provides efficient front-end processing of multispectral image data by adaptively segmenting and routing portions of the scene data concurrently to an imager and a spectrometer. The goal is to provide a large reduction in the amount of data required to be sensed in a multispectral imager by means of preprocessing the data to extract the most useful spatial and spectral information during detection. The DMD array provides the flexibility to perform a wide range of spatial and spectral analyses on the scene data. The spatial and spectral processing for different portions of the input scene can be tailored in real time to achieve a variety of preprocessing functions. Since the detected intensity of individual pixels may be controlled, the spatial image can be analyzed with gain varied on a pixel-by-pixel basis to enhance dynamic range. Coarse or fine spectral resolution can be achieved in the spectrometer by use of dynamically controllable or addressable dispersion elements. An experimental prototype, which demonstrated the segmentation between an imager and a grating spectrometer, was demonstrated and shown to achieve programmable pixelated intensity control. An information theoretic analysis of the dynamic-range control aspect was conducted to predict the performance enhancements that might be achieved with this architecture. The results indicate that, with a properly configured algorithm, the concept achieves the greatest relative information recovery from a detected image when the scene is made up of a relatively large area of moderate-dynamic-range pixels and a relatively smaller area of strong pixels that would tend to saturate a conventional sensor. PMID:12389978

  14. Characterisation of a PERCIVAL monolithic active pixel prototype using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Correa, J.; Bayer, M.; Göttlicher, P.; Lange, S.; Marras, A.; Niemann, M.; Reza, S.; Shevyakov, I.; Smoljanin, S.; Tennert, M.; Xia, Q.; Viti, M.; Wunderer, C. B.; Zimmer, M.; Dipayan, D.; Guerrini, N.; Marsh, B.; Sedgwick, I.; Turchetta, R.; Cautero, G.; Giuressi, D.; Khromova, A.; Pinaroli, G.; Menk, R.; Stebel, L.; Fan, R.; Marchal, J.; Pedersen, U.; Rees, N.; Steadman, P.; Sussmuth, M.; Tartoni, N.; Yousef, H.; Hyun, H. J.; Kim, K.; Rah, S.; Graafsma, H.

    2016-02-01

    PERCIVAL ("Pixelated Energy Resolving CMOS Imager, Versatile And Large") is a monolithic active pixel sensor (MAPS) based on CMOS technology. Is being developed by DESY, RAL/STFC, Elettra, DLS, and PAL to address the various requirements of detectors at synchrotron radiation sources and Free Electron Lasers (FELs) in the soft X-ray regime. These requirements include high frame rates and FELs base-rate compatibility, large dynamic range, single-photon counting capability with low probability of false positives, high quantum efficiency (QE), and (multi-)megapixel arrangements with good spatial resolution. Small-scale back-side-illuminated (BSI) prototype systems are undergoing detailed testing with X-rays and optical photons, in preparation of submission of a larger sensor. A first BSI processed prototype was tested in 2014 and a preliminary result—first detection of 350eV photons with some pixel types of PERCIVAL—reported at this meeting a year ago. Subsequent more detailed analysis revealed a very low QE and pointed to contamination as a possible cause. In the past year, BSI-processed chips on two more wafers were tested and their response to soft X-ray evaluated. We report here the improved charge collection efficiency (CCE) of different PERCIVAL pixel types for 400eV soft X-rays together with Airy patterns, response to a flat field, and noise performance for such a newly BSI-processed prototype sensor.

  15. Characterisation of a CMOS active pixel sensor for use in the TEAM microscope

    NASA Astrophysics Data System (ADS)

    Battaglia, Marco; Contarato, Devis; Denes, Peter; Doering, Dionisio; Duden, Thomas; Krieger, Brad; Giubilato, Piero; Gnani, Dario; Radmilovic, Velimir

    2010-10-01

    A 1M- and a 4M-pixel monolithic CMOS active pixel sensor with 9.5×9.5 μm2 pixels have been developed for direct imaging in transmission electron microscopy as part of the TEAM project. We present the design and a full characterisation of the detector. Data collected with electron beams at various energies of interest in electron microscopy are used to determine the detector response. Data are compared to predictions of simulation. The line spread function measured with 80 and 300 keV electrons is (12.1±0.7) and (7.4±0.6) μm, respectively, in good agreement with our simulation. We measure the detection quantum efficiency to be 0.78±0.04 at 80 keV and 0.74±0.03 at 300 keV. Using a new imaging technique, based on single electron reconstruction, the line spread function for 80 and 300 keV electrons becomes (6.7±0.3) and (2.4±0.2) μm, respectively. The radiation tolerance of the pixels has been tested up to 5 Mrad and the detector is still functional with a decrease of dynamic range by ≃30%, corresponding to a reduction in full-well depth from ˜39 to ˜27 primary 300 keV electrons, due to leakage current increase, but identical line spread function performance.

  16. Direct electron imaging in electron microscopy with monolithic active pixel sensors.

    PubMed

    Deptuch, G; Besson, A; Rehak, P; Szelezniak, M; Wall, J; Winter, M; Zhu, Y

    2007-08-01

    A new imaging device for dynamic electron microscopy is in great demand. The detector should provide the experimenter with images having sufficient spatial resolution at high speed. Immunity to radiation damage, accumulated during exposures, is critical. Photographic film, a traditional medium, is not adequate for studies that require large volumes of data or rapid recording and charge coupled device (CCD) cameras have limited resolution, due to phosphor screen coupling. CCD chips are not suitable for direct recording due to their extreme sensitivity to radiation damage. This paper discusses characterization of monolithic active pixel sensors (MAPS) in a scanning electron microscope (SEM) as well as in a transmission electron microscope (TEM). The tested devices were two versions of the MIMOSA V (MV) chip. This 1M pixel device features pixel size of 17 x 17 microm(2) and was designed in a 0.6 microm CMOS process. The active layer for detection is a thin (less than 20 microm) epitaxial layer, limiting the broadening of the electron beam. The first version of the detector was a standard imager with electronics, passivation and interconnection layers on top of the active region; the second one was bottom-thinned, reaching the epitaxial layer from the bottom. The electron energies used range from a few keV to 30 keV for SEM and from 40 to 400 keV for TEM. Deterioration of the image resolution due to backscattering was quantified for different energies and both detector versions. PMID:17346890

  17. Characteristics of Monolithically Integrated InGaAs Active Pixel Imager Array

    NASA Technical Reports Server (NTRS)

    Kim, Q.; Cunningham, T. J.; Pain, B.; Lange, M. J.; Olsen, G. H.

    2000-01-01

    Switching and amplifying characteristics of a newly developed monolithic InGaAs Active Pixel Imager Array are presented. The sensor array is fabricated from InGaAs material epitaxially deposited on an InP substrate. It consists of an InGaAs photodiode connected to InP depletion-mode junction field effect transistors (JFETs) for low leakage, low power, and fast control of circuit signal amplifying, buffering, selection, and reset. This monolithically integrated active pixel sensor configuration eliminates the need for hybridization with silicon multiplexer. In addition, the configuration allows the sensor to be front illuminated, making it sensitive to visible as well as near infrared signal radiation. Adapting the existing 1.55 micrometer fiber optical communication technology, this integration will be an ideal system of optoelectronic integration for dual band (Visible/IR) applications near room temperature, for use in atmospheric gas sensing in space, and for target identification on earth. In this paper, two different types of small 4 x 1 test arrays will be described. The effectiveness of switching and amplifying circuits will be discussed in terms of circuit effectiveness (leakage, operating frequency, and temperature) in preparation for the second phase demonstration of integrated, two-dimensional monolithic InGaAs active pixel sensor arrays for applications in transportable shipboard surveillance, night vision, and emission spectroscopy.

  18. Development of active edge pixel sensors and four-side buttable modules using vertical integration technologies

    NASA Astrophysics Data System (ADS)

    Macchiolo, A.; Andricek, L.; Moser, H.-G.; Nisius, R.; Richter, R. H.; Terzo, S.; Weigell, P.

    2014-11-01

    We present an R&D activity focused on the development of novel modules for the upgrade of the ATLAS pixel system at the High Luminosity LHC (HL-LHC). The modules consist of n-in-p pixel sensors, 100 or 200 μm thick, produced at VTT (Finland) with an active edge technology, which considerably reduces the dead area at the periphery of the device. The sensors are interconnected with solder bump-bonding to the ATLAS FE-I3 and FE-I4 read-out chips, and characterised with radioactive sources and beam tests at the CERN-SPS and DESY. The results of these measurements will be discussed for devices before and after irradiation up to a fluence of 5 ×1015neq /cm2. We will also report on the R&D activity to obtain Inter Chip Vias (ICVs) on the ATLAS read-out chip in collaboration with the Fraunhofer Institute EMFT. This step is meant to prove the feasibility of the signal transport to the newly created readout pads on the backside of the chips allowing for four side buttable devices without the presently used cantilever for wire bonding. The read-out chips with ICVs will be interconnected to thin pixel sensors, 75 μm and 150 μm thick, with the Solid Liquid Interdiffusion (SLID) technology, which is an alternative to the standard solder bump-bonding.

  19. Characterization of Depleted Monolithic Active Pixel detectors implemented with a high-resistive CMOS technology

    NASA Astrophysics Data System (ADS)

    Kishishita, T.; Hemperek, T.; Rymaszewski, P.; Hirono, T.; Krüger, H.; Wermes, N.

    2016-07-01

    We present the recent development of DMAPS (Depleted Monolithic Active Pixel Sensor), implemented with a Toshiba 130 nm CMOS process. Unlike in the case of standard MAPS technologies which are based on an epi-layer, this process provides a high-resistive substrate that enables larger signal and faster charge collection by drift in a 50 - 300 μm thick depleted layer. Since this process also enables the use of deep n-wells to isolate the collection electrodes from the thin active device layer, NMOS and PMOS transistors are available for the readout electronics in each pixel cell. In order to characterize the technology, we implemented a simple three transistor readout with a variety of pixel pitches and input FET sizes. This layout variety gives us a clue on sensor characteristics for future optimization, such as the input detector capacitance or leakage current. In the initial measurement, the radiation spectra were obtained from 55Fe with an energy resolution of 770 eV (FWHM) and 90Sr with the MVP of 4165 e-.

  20. CMOS Active Pixel Sensors as energy-range detectors for proton Computed Tomography

    NASA Astrophysics Data System (ADS)

    Esposito, M.; Anaxagoras, T.; Evans, P. M.; Green, S.; Manolopoulos, S.; Nieto-Camero, J.; Parker, D. J.; Poludniowski, G.; Price, T.; Waltham, C.; Allinson, N. M.

    2015-06-01

    Since the first proof of concept in the early 70s, a number of technologies has been proposed to perform proton CT (pCT), as a means of mapping tissue stopping power for accurate treatment planning in proton therapy. Previous prototypes of energy-range detectors for pCT have been mainly based on the use of scintillator-based calorimeters, to measure proton residual energy after passing through the patient. However, such an approach is limited by the need for only a single proton passing through the energy-range detector in a read-out cycle. A novel approach to this problem could be the use of pixelated detectors, where the independent read-out of each pixel allows to measure simultaneously the residual energy of a number of protons in the same read-out cycle, facilitating a faster and more efficient pCT scan. This paper investigates the suitability of CMOS Active Pixel Sensors (APSs) to track individual protons as they go through a number of CMOS layers, forming an energy-range telescope. Measurements performed at the iThemba Laboratories will be presented and analysed in terms of correlation, to confirm capability of proton tracking for CMOS APSs.

  1. Monolithic active pixel sensor development for the upgrade of the ALICE inner tracking system

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    ALICE plans an upgrade of its Inner Tracking System for 2018. The development of a monolithic active pixel sensor for this upgrade is described. The TowerJazz 180 nm CMOS imaging sensor process has been chosen as it is possible to use full CMOS in the pixel due to the offering of a deep pwell and also to use different starting materials. The ALPIDE development is an alternative to approaches based on a rolling shutter architecture, and aims to reduce power consumption and integration time by an order of magnitude below the ALICE specifications, which would be quite beneficial in terms of material budget and background. The approach is based on an in-pixel binary front-end combined with a hit-driven architecture. Several prototypes have already been designed, submitted for fabrication and some of them tested with X-ray sources and particles in a beam. Analog power consumption has been limited by optimizing the Q/C of the sensor using Explorer chips. Promising but preliminary first results have also been obtained with a prototype ALPIDE. Radiation tolerance up to the ALICE requirements has also been verified.

  2. Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging.

    PubMed

    Esposito, M; Anaxagoras, T; Konstantinidis, A C; Zheng, Y; Speller, R D; Evans, P M; Allinson, N M; Wells, K

    2014-07-01

    Recently CMOS active pixels sensors (APSs) have become a valuable alternative to amorphous silicon and selenium flat panel imagers (FPIs) in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However, despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Non-uniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uniformity and regional variations of a wafer scale stitched CMOS APS. For the first time a per-pixel analysis of the electro-optical performance of a wafer CMOS APS is presented, to address inhomogeneity issues arising from the stitching techniques used to manufacture wafer scale sensors. A complete model of the signal generation in the pixel array has been provided and proved capable of accounting for noise and gain variations across the pixel array. This novel analysis leads to readout noise and conversion gain being evaluated at pixel level, stitching block level and in regions of interest, resulting in a coefficient of variation ⩽1.9%. The uniformity of the image quality performance has been further investigated in a typical x-ray application, i.e. mammography, showing a uniformity in terms of CNR among the highest when compared with mammography detectors commonly used in clinical practice. Finally, in order to compare the detection capability of this novel APS with the technology currently used (i.e. FPIs), theoretical evaluation of the detection quantum efficiency (DQE) at zero-frequency has been performed, resulting in a higher DQE for this

  3. Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging

    NASA Astrophysics Data System (ADS)

    Esposito, M.; Anaxagoras, T.; Konstantinidis, A. C.; Zheng, Y.; Speller, R. D.; Evans, P. M.; Allinson, N. M.; Wells, K.

    2014-07-01

    Recently CMOS active pixels sensors (APSs) have become a valuable alternative to amorphous silicon and selenium flat panel imagers (FPIs) in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However, despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Non-uniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uniformity and regional variations of a wafer scale stitched CMOS APS. For the first time a per-pixel analysis of the electro-optical performance of a wafer CMOS APS is presented, to address inhomogeneity issues arising from the stitching techniques used to manufacture wafer scale sensors. A complete model of the signal generation in the pixel array has been provided and proved capable of accounting for noise and gain variations across the pixel array. This novel analysis leads to readout noise and conversion gain being evaluated at pixel level, stitching block level and in regions of interest, resulting in a coefficient of variation ⩽1.9%. The uniformity of the image quality performance has been further investigated in a typical x-ray application, i.e. mammography, showing a uniformity in terms of CNR among the highest when compared with mammography detectors commonly used in clinical practice. Finally, in order to compare the detection capability of this novel APS with the technology currently used (i.e. FPIs), theoretical evaluation of the detection quantum efficiency (DQE) at zero-frequency has been performed, resulting in a higher DQE for this

  4. Development of CMOS Active Pixel Image Sensors for Low Cost Commercial Applications

    NASA Technical Reports Server (NTRS)

    Gee, R.; Kemeny, S.; Kim, Q.; Mendis, S.; Nakamura, J.; Nixon, R.; Ortiz, M.; Pain, B.; Staller, C.; Zhou, Z; Fossum, E.

    1994-01-01

    JPL, under sponsorship from the NASA Office of Advanced Concepts and Technology, has been developing a second-generation solid-state image sensor technology. Charge-coupled devices (CCD) are a well-established first generation image sensor technology. For both commercial and NASA applications, CCDs have numerous shortcomings. In response, the active pixel sensor (APS) technology has been under research. The major advantages of APS technology are the ability to integrate on-chip timing, control, signal-processing and analog-to-digital converter functions, reduced sensitivity to radiation effects, low power operation, and random access readout.

  5. Optical and electrical characterization of a back-thinned CMOS active pixel sensor

    NASA Astrophysics Data System (ADS)

    Blue, Andrew; Clark, A.; Houston, S.; Laing, A.; Maneuski, D.; Prydderch, M.; Turchetta, R.; O'Shea, V.

    2009-06-01

    This work will report on the first work on the characterization of a back-thinned Vanilla-a 512×512 (25 μm squared) active pixel sensor (APS). Characterization of the detectors was carried out through the analysis of photon transfer curves to yield a measurement of full well capacity, noise levels, gain constants and linearity. Spectral characterization of the sensors was also performed in the visible and UV regions. A full comparison against non-back-thinned front illuminated Vanilla sensors is included. Such measurements suggest that the Vanilla APS will be suitable for a wide range of applications, including particle physics and biomedical imaging.

  6. Development of CMOS Active Pixel Image Sensors for Low Cost Commercial Applications

    NASA Technical Reports Server (NTRS)

    Fossum, E.; Gee, R.; Kemeny, S.; Kim, Q.; Mendis, S.; Nakamura, J.; Nixon, R.; Ortiz, M.; Pain, B.; Zhou, Z.; Ackland, B.; Dickinson, A.; Eid, E.; Inglis, D.

    1994-01-01

    This paper describes ongoing research and development of CMOS active pixel image sensors for low cost commercial applications. A number of sensor designs have been fabricated and tested in both p-well and n-well technologies. Major elements in the development of the sensor include on-chip analog signal processing circuits for the reduction of fixed pattern noise, on-chip timing and control circuits and on-chip analog-to-digital conversion (ADC). Recent results and continuing efforts in these areas will be presented.

  7. Improved Design of Active Pixel CMOS Sensors for Charged Particle Detection

    SciTech Connect

    Deptuch, Grzegorz

    2007-11-12

    The Department of Energy (DOE) nuclear physics program requires developments in detector instrumentation electronics with improved energy, position and timing resolution, sensitivity, rate capability, stability, dynamic range, and background suppression. The current Phase-I project was focused on analysis of standard-CMOS photogate Active Pixel Sensors (APS) as an efficient solution to this challenge. The advantages of the CMOS APS over traditional hybrid approaches (i.e., separate detection regions bump-bonded to readout circuits) include greatly reduced cost, low power and the potential for vastly larger pixel counts and densities. However, challenges remain in terms of the signal-to-noise ratio (SNR) and readout speed (currently on the order of milliseconds), which is the major problem for this technology. Recent work has shown that the long readout time for photogate APS is due to the presence of (interface) traps at the semiconductor-oxide interface. This Phase-I work yielded useful results in two areas: (a) Advanced three-dimensional (3D) physics-based simulation models and simulation-based analysis of the impact of interface trap density on the transient charge collection characteristics of existing APS structures; and (b) Preliminary analysis of the feasibility of an improved photogate pixel structure (i.e., new APS design) with an induced electric field under the charge collecting electrode to enhance charge collection. Significant effort was dedicated in Phase-I to the critical task of implementing accurate interface trap models in CFDRC's NanoTCAD 3D semiconductor device-physics simulator. This resulted in validation of the new NanoTCAD models and simulation results against experimental (published) data, within the margin of uncertainty associated with obtaining device geometry, material properties, and experimentation details. Analyses of the new, proposed photogate APS design demonstrated several promising trends.

  8. TFT-Based Active Pixel Sensors for Large Area Thermal Neutron Detection

    NASA Astrophysics Data System (ADS)

    Kunnen, George

    Due to diminishing availability of 3He, which is the critical component of neutron detecting proportional counters, large area flexible arrays are being considered as a potential replacement for neutron detection. A large area flexible array, utilizing semiconductors for both charged particle detection and pixel readout, ensures a large detection surface area in a light weight rugged form. Such a neutron detector could be suitable for deployment at ports of entry. The specific approach used in this research, uses a neutron converter layer which captures incident thermal neutrons, and then emits ionizing charged particles. These ionizing particles cause electron-hole pair generation within a single pixel's integrated sensing diode. The resulting charge is then amplified via a low-noise amplifier. This document begins by discussing the current state of the art in neutron detection and the associated challenges. Then, for the purpose of resolving some of these issues, recent design and modeling efforts towards developing an improved neutron detection system are described. Also presented is a low-noise active pixel sensor (APS) design capable of being implemented in low temperature indium gallium zinc oxide (InGaZnO) or amorphous silicon (a-Si:H) thin film transistor process compatible with plastic substrates. The low gain and limited scalability of this design are improved upon by implementing a new multi-stage self-resetting APS. For each APS design, successful radiation measurements are also presented using PiN diodes for charged particle detection. Next, detection array readout methodologies are modeled and analyzed, and use of a matched filter readout circuit is described as well. Finally, this document discusses detection diode integration with the designed TFT-based APSs.

  9. Method of fabrication of display pixels driven by silicon thin film transistors

    DOEpatents

    Carey, Paul G.; Smith, Patrick M.

    1999-01-01

    Display pixels driven by silicon thin film transistors are fabricated on plastic substrates for use in active matrix displays, such as flat panel displays. The process for forming the pixels involves a prior method for forming individual silicon thin film transistors on low-temperature plastic substrates. Low-temperature substrates are generally considered as being incapable of withstanding sustained processing temperatures greater than about 200.degree. C. The pixel formation process results in a complete pixel and active matrix pixel array. A pixel (or picture element) in an active matrix display consists of a silicon thin film transistor (TFT) and a large electrode, which may control a liquid crystal light valve, an emissive material (such as a light emitting diode or LED), or some other light emitting or attenuating material. The pixels can be connected in arrays wherein rows of pixels contain common gate electrodes and columns of pixels contain common drain electrodes. The source electrode of each pixel TFT is connected to its pixel electrode, and is electrically isolated from every other circuit element in the pixel array.

  10. 50 μm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Zhao, C.; Konstantinidis, A. C.; Zheng, Y.; Anaxagoras, T.; Speller, R. D.; Kanicki, J.

    2015-12-01

    Wafer-scale CMOS active pixel sensors (APSs) have been developed recently for x-ray imaging applications. The small pixel pitch and low noise are very promising properties for medical imaging applications such as digital breast tomosynthesis (DBT). In this work, we evaluated experimentally and through modeling the imaging properties of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). A modified cascaded system model was developed for CMOS APS x-ray detectors by taking into account the device nonlinear signal and noise properties. The imaging properties such as modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were extracted from both measurements and the nonlinear cascaded system analysis. The results show that the DynAMITe x-ray detector achieves a high spatial resolution of 10 mm-1 and a DQE of around 0.5 at spatial frequencies  <1 mm-1. In addition, the modeling results were used to calculate the image signal-to-noise ratio (SNRi) of microcalcifications at various mean glandular dose (MGD). For an average breast (5 cm thickness, 50% glandular fraction), 165 μm microcalcifications can be distinguished at a MGD of 27% lower than the clinical value (~1.3 mGy). To detect 100 μm microcalcifications, further optimizations of the CMOS APS x-ray detector, image aquisition geometry and image reconstruction techniques should be considered.

  11. 50 μm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis.

    PubMed

    Zhao, C; Konstantinidis, A C; Zheng, Y; Anaxagoras, T; Speller, R D; Kanicki, J

    2015-12-01

    Wafer-scale CMOS active pixel sensors (APSs) have been developed recently for x-ray imaging applications. The small pixel pitch and low noise are very promising properties for medical imaging applications such as digital breast tomosynthesis (DBT). In this work, we evaluated experimentally and through modeling the imaging properties of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). A modified cascaded system model was developed for CMOS APS x-ray detectors by taking into account the device nonlinear signal and noise properties. The imaging properties such as modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were extracted from both measurements and the nonlinear cascaded system analysis. The results show that the DynAMITe x-ray detector achieves a high spatial resolution of 10 mm(-1) and a DQE of around 0.5 at spatial frequencies  <1 mm(-1). In addition, the modeling results were used to calculate the image signal-to-noise ratio (SNRi) of microcalcifications at various mean glandular dose (MGD). For an average breast (5 cm thickness, 50% glandular fraction), 165 μm microcalcifications can be distinguished at a MGD of 27% lower than the clinical value (~1.3 mGy). To detect 100 μm microcalcifications, further optimizations of the CMOS APS x-ray detector, image aquisition geometry and image reconstruction techniques should be considered. PMID:26540090

  12. Silicon-on-insulator (SOI) active pixel sensors with the photosite implemented in the substrate

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor); Zheng, Xinyu (Inventor)

    2002-01-01

    Active pixel sensors for a high quality imager are fabricated using a silicon-on-insulator (SOI) process by integrating the photodetectors on the SOI substrate and forming pixel readout transistors on the SOI thin-film. The technique can include forming silicon islands on a buried insulator layer disposed on a silicon substrate and selectively etching away the buried insulator layer over a region of the substrate to define a photodetector area. Dopants of a first conductivity type are implanted to form a signal node in the photodetector area and to form simultaneously drain/source regions for a first transistor in at least a first one of the silicon islands. Dopants of a second conductivity type are implanted to form drain/source regions for a second transistor in at least a second one of the silicon islands. Isolation rings around the photodetector also can be formed when dopants of the second conductivity type are implanted. Interconnections among the transistors and the photodetector are provided to allow signals sensed by the photodetector to be read out via the transistors formed on the silicon islands.

  13. Silicon-on-insulator (SOI) active pixel sensors with the photosite implemented in the substrate

    NASA Technical Reports Server (NTRS)

    Zheng, Xinyu (Inventor); Pain, Bedabrata (Inventor)

    2005-01-01

    Active pixel sensors for a high quality imager are fabricated using a silicon-on-insulator (SOI) process by integrating the photodetectors on the SOI substrate and forming pixel readout transistors on the SOI thin-film. The technique can include forming silicon islands on a buried insulator layer disposed on a silicon substrate and selectively etching away the buried insulator layer over a region of the substrate to define a photodetector area. Dopants of a first conductivity type are implanted to form a signal node in the photodetector area and to form simultaneously drain/source regions for a first transistor in at least a first one of the silicon islands. Dopants of a second conductivity type are implanted to form drain/source regions for a second transistor in at least a second one of the silicon islands. Isolation rings around the photodetector also can be formed when dopants of the second conductivity type are implanted. Interconnections among the transistors and the photodetector are provided to allow signals sensed by the photodetector to be read out via the transistors formed on the silicon islands.

  14. Direct tests of a pixelated microchannel plate as the active element of a shower maximum detector

    NASA Astrophysics Data System (ADS)

    Apresyan, A.; Los, S.; Pena, C.; Presutti, F.; Ronzhin, A.; Spiropulu, M.; Xie, S.

    2016-08-01

    One possibility to make a fast and radiation resistant shower maximum detector is to use a secondary emitter as an active element. We report our studies of microchannel plate photomultipliers (MCPs) as the active element of a shower-maximum detector. We present test beam results obtained using Photonis XP85011 to detect secondary particles of an electromagnetic shower. We focus on the use of the multiple pixels on the Photonis MCP in order to find a transverse two-dimensional shower distribution. A spatial resolution of 0.8 mm was obtained with an 8 GeV electron beam. A method for measuring the arrival time resolution for electromagnetic showers is presented, and we show that time resolution better than 40 ps can be achieved.

  15. Direct tests of a pixelated microchannel plate as the active element of a shower maximum detector

    DOE PAGES

    Apresyan, A.; Los, S.; Pena, C.; Presutti, F.; Ronzhin, A.; Spiropulu, M.; Xie, S.

    2016-05-07

    One possibility to make a fast and radiation resistant shower maximum detector is to use a secondary emitter as an active element. We report our studies of microchannel plate photomultipliers (MCPs) as the active element of a shower-maximum detector. We present test beam results obtained using Photonis XP85011 to detect secondary particles of an electromagnetic shower. We focus on the use of the multiple pixels on the Photonis MCP in order to find a transverse two-dimensional shower distribution. A spatial resolution of 0.8 mm was obtained with an 8 GeV electron beam. As a result, a method for measuring themore » arrival time resolution for electromagnetic showers is presented, and we show that time resolution better than 40 ps can be achieved.« less

  16. Impact of Substrate Bias on Fixed-Pattern-Noise in Active Pixel Sensor Cells

    NASA Astrophysics Data System (ADS)

    Terauchi, Mamoru

    2007-11-01

    The effect of substrate (body) bias on fixed-pattern-noise (FPN) in active pixel sensor (APS) cells is studied. Through measuring test devices consisting of two metal-oxide-semiconductor field-effect transistors (MOSFETs) connected in series with each of the transistors located in the same well region, it has been revealed that substrate bias, which is inevitably applied in a normal circuit configuration in conventional APS cells, worsens the characteristics fluctuation in source-follower amplifiers in APS cells, leading to FPN that cannot be mitigated by conventional correction methods such as correlated double sampling. In addition it has been confirmed that the current-voltage characteristics of logarithmic converters, each of which is realized using a MOSFET with gate and drain terminals connected together, are also affected by substrate bias, resulting in increased characteristics fluctuation as compared with the case with no substrate bias.

  17. Characterization of a photon-counting intensified active pixel sensor (PC-IAPS): preliminary results

    NASA Astrophysics Data System (ADS)

    Uslenghi, Michela C.; Bonanno, Giovanni; Belluso, Massimiliano; Modica, Angelo; Bergamini, Paolo

    2001-12-01

    We report about preliminary results of the characterization of a new kind of MCP-based detector: a Photon Counting Intensified Active Pixel Sensor (APS). PC-IAPS appears as the natural evolution of the Intensified CCD, maintaining the basic characteristics, but with improved performance in terms of dynamic range, along with some other appealing properties: higher radiation hardness, more compact design, lower requirements on the external electronics, low power consumption. The prototype we realized is currently in an early stage of development. Nevertheless, it allows us to demonstrate the feasibility of the photon counter and to measure some of the basic parameters. Some of the characteristics of the APS, relevant to the use in intensified systems, are analyzed and compared with the CCD ones, demonstrating the potentiality of the new device and allowing us to set the basis of future development.

  18. Intelligent error correction method applied on an active pixel sensor based star tracker

    NASA Astrophysics Data System (ADS)

    Schmidt, Uwe

    2005-10-01

    Star trackers are opto-electronic sensors used on-board of satellites for the autonomous inertial attitude determination. During the last years star trackers became more and more important in the field of the attitude and orbit control system (AOCS) sensors. High performance star trackers are based up today on charge coupled device (CCD) optical camera heads. The active pixel sensor (APS) technology, introduced in the early 90-ties, allows now the beneficial replacement of CCD detectors by APS detectors with respect to performance, reliability, power, mass and cost. The company's heritage in star tracker design started in the early 80-ties with the launch of the worldwide first fully autonomous star tracker system ASTRO1 to the Russian MIR space station. Jena-Optronik recently developed an active pixel sensor based autonomous star tracker "ASTRO APS" as successor of the CCD based star tracker product series ASTRO1, ASTRO5, ASTRO10 and ASTRO15. Key features of the APS detector technology are, a true xy-address random access, the multiple windowing read out and the on-chip signal processing including the analogue to digital conversion. These features can be used for robust star tracking at high slew rates and under worse conditions like stray light and solar flare induced single event upsets. A special algorithm have been developed to manage the typical APS detector error contributors like fixed pattern noise (FPN), dark signal non-uniformity (DSNU) and white spots. The algorithm works fully autonomous and adapts to e.g. increasing DSNU and up-coming white spots automatically without ground maintenance or re-calibration. In contrast to conventional correction methods the described algorithm does not need calibration data memory like full image sized calibration data sets. The application of the presented algorithm managing the typical APS detector error contributors is a key element for the design of star trackers for long term satellite applications like

  19. Neutrophil activator of matrix metalloproteinase-2 (NAM).

    PubMed

    Rollo, Ellen E; Hymowitz, Michelle; Schmidt, Cathleen E; Montana, Steve; Foda, Hussein; Zucker, Stanley

    2006-01-01

    We have isolated a novel soluble factor(s), neutrophil activator of matrix metalloproteinases (NAM), secreted by unstimulated normal human peripheral blood neutrophils that causes the activation of cell secreted promatrix metalloproteinase-2 (proMMP-2). Partially purified preparations of NAM have been isolated from the conditioned media of neutrophils employing gelatin-Sepharose chromatography and differential membrane filter centrifugation. NAM activity, as assessed by exposing primary human umbilical vein endothelial cells (HUVEC) or HT1080 cells to NAM followed by gelatin zymography, was seen within one hour. Tissue inhibitor of metalloproteinase-2 (TIMP-2) and hydroxamic acid derived inhibitors of MMPs (CT1746 and BB94) abrogated the activation of proMMP-2 by NAM, while inhibitors of serine and cysteine proteases showed no effect. NAM also produced an increase in TIMP-2 binding to HUVEC and HT1080 cell surfaces that was inhibited by TIMP-2, CT1746, and BB94. Time-dependent increases in MT1-MMP protein and mRNA were seen following the addition of NAM to cells. These data support a role for NAM in cancer dissemination.

  20. Voltage Drop Compensation Method for Active Matrix Organic Light Emitting Diode Displays

    NASA Astrophysics Data System (ADS)

    Choi, Sang-moo; Ryu, Do-hyung; Kim, Keum-nam; Choi, Jae-beom; Kim, Byung-hee; Berkeley, Brian

    2011-03-01

    In this paper, the conventional voltage drop compensation methods are reviewed and the novel design and driving scheme, the advanced power de-coupled (aPDC) driving method, is proposed to effectively compensate the voltage IR drop of active matrix light emitting diode (AMOLED) displays. The advanced PDC driving scheme can be applied to general AMOLED pixel circuits that have been developed with only minor modification or without requiring modification in pixel circuit. A 14-in. AMOLED panel with the aPDC driving scheme was fabricated. Long range uniformity (LRU) of the 14-in. AMOLED panel was improved from 43% without the aPDC driving scheme, to over 87% at the same brightness by using the scheme and the layout complexity of the panel with new design scheme is less than that of the panel with the conventional design scheme.

  1. Three-dimensional display utilizing a diffractive optical element and an active matrix liquid crystal display

    NASA Astrophysics Data System (ADS)

    Nordin, Gregory P.; Jones, Michael W.; Kulick, Jeffrey H.; Lindquist, Robert G.; Kowel, Stephen T.

    1996-12-01

    We describe the design, construction, and performance of the first real-time autostereoscopic 3D display based on the partial pixel 3D display architecture. The primary optical components of the 3D display are an active-matrix liquid crystal display and a diffractive optical element (DOE). The display operates at video frame rates and is driven with a conventional VGA signal. 3D animations with horizontal motion parallax are readily viewable as sets of stereo images. Formation of the virtual viewing slits by diffraction from the partial pixel apertures is experimentally verified. The measured contrast and perceived brightness of the display are excellent, but there are minor flaws in image quality due to secondary images. The source of these images and how they may be eliminated is discussed. The effects of manufacturing-related systematic errors in the DOE are also analyzed.

  2. Integrated X-ray and charged particle active pixel CMOS sensor arrays using an epitaxial silicon sensitive region

    SciTech Connect

    Kleinfelder, Stuart; Bichsel, Hans; Bieser, Fred; Matis, Howard S.; Rai, Gulshan; Retiere, Fabrice; Weiman, Howard; Yamamoto, Eugene

    2002-07-01

    Integrated CMOS Active Pixel Sensor (APS) arrays have been fabricated and tested using X-ray and electron sources. The 128 by 128 pixel arrays, designed in a standard 0.25 micron process, use a {approx}10 micron epitaxial silicon layer as a deep detection region. The epitaxial layer has a much greater thickness than the surface features used by standard CMOS APS, leading to stronger signals and potentially better signal-to-noise ratio (SNR). On the other hand, minority carriers confined within the epitaxial region may diffuse to neighboring pixels, blur images and reduce peak signal intensity. But for low-rate, sparse-event images, centroid analysis of this diffusion may be used to increase position resolution. Careful trade-offs involving pixel size and sense-node area verses capacitance must be made to optimize overall performance. The prototype sensor arrays, therefore, include a range of different pixel designs, including different APS circuits and a range of different epitaxial layer contact structures. The fabricated arrays were tested with 1.5 GeV electrons and Fe-55 X-ray sources, yielding a measured noise of 13 electrons RMS and an SNR for single Fe-55 X-rays of greater than 38.

  3. A Monolithic Active Pixel Sensor for ionizing radiation using a 180 nm HV-SOI process

    NASA Astrophysics Data System (ADS)

    Hemperek, Tomasz; Kishishita, Tetsuichi; Krüger, Hans; Wermes, Norbert

    2015-10-01

    An improved SOI-MAPS (Silicon On Insulator Monolithic Active Pixel Sensor) for ionizing radiation based on thick-film High Voltage SOI technology (HV-SOI) has been developed. Similar to existing Fully Depleted SOI-based (FD-SOI) MAPS, a buried silicon oxide inter-dielectric (BOX) layer is used to separate the CMOS electronics from the handle wafer which is used as a depleted charge collection layer. FD-SOI MAPS suffers from radiation damage such as transistor threshold voltage shifts due to charge traps in the oxide layers and charge states created at the silicon oxide boundaries (back gate effect). The X-FAB 180-nm HV-SOI technology offers an additional isolation by deep non-depleted implant between the BOX layer and the active circuitry which mitigates this problem. Therefore we see in this technology a high potential to implement radiation-tolerant MAPS with fast charge collection property. The design and measurement results from a first prototype are presented including charge collection in neutron irradiated samples.

  4. Active pixel image sensor with a winner-take-all mode of operation

    NASA Technical Reports Server (NTRS)

    Yadid-Pecht, Orly (Inventor); Fossum, Eric R. (Inventor); Mead, Carver (Inventor)

    2003-01-01

    An integrated CMOS semiconductor imaging device having two modes of operation that can be performed simultaneously to produce an output image and provide information of a brightest or darkest pixel in the image.

  5. A novel source-drain follower for monolithic active pixel sensors

    NASA Astrophysics Data System (ADS)

    Gao, C.; Aglieri, G.; Hillemanns, H.; Huang, G.; Junique, A.; Keil, M.; Kim, D.; Kofarago, M.; Kugathasan, T.; Mager, M.; Marin Tobon, C. A.; Martinengo, P.; Mugnier, H.; Musa, L.; Lee, S.; Reidt, F.; Riedler, P.; Rousset, J.; Sielewicz, K. M.; Snoeys, W.; Sun, X.; Van Hoorne, J. W.; Yang, P.

    2016-09-01

    Monolithic active pixel sensors (MAPS) receive interest in tracking applications in high energy physics as they integrate sensor and readout electronics in one silicon die with potential for lower material budget and cost, and better performance. Source followers (SFs) are widely used for MAPS readout: they increase charge conversion gain 1/Ceff or decrease the effective sensing node capacitance Ceff because the follower action compensates part of the input capacitance. Charge conversion gain is critical for analog power consumption and therefore for material budget in tracking applications, and also has direct system impact. This paper presents a novel source-drain follower (SDF), where both source and drain follow the gate potential improving charge conversion gain. For the inner tracking system (ITS) upgrade of the ALICE experiment at CERN, low material budget is a primary requirement. The SDF circuit was studied as part of the effort to optimize the effective capacitance of the sensing node. The collection electrode, input transistor and routing metal all contribute to Ceff. Reverse sensor bias reduces the collection electrode capacitance. The novel SDF circuit eliminates the contribution of the input transistor to Ceff, reduces the routing contribution if additional shielding is introduced, provides a way to estimate the capacitance of the sensor itself, and has a voltage gain closer to unity than the standard SF. The SDF circuit has a somewhat larger area with a somewhat smaller bandwidth, but this is acceptable in most cases. A test chip, manufactured in a 180 nm CMOS image sensor process, implements small prototype pixel matrices in different flavors to compare the standard SF to the novel SF and to the novel SF with additional shielding. The effective sensing node capacitance was measured using a 55Fe source. Increasing reverse substrate bias from -1 V to -6 V reduces Ceff by 38% and the equivalent noise charge (ENC) by 22% for the standard SF. The SDF

  6. Towards real-time VMAT verification using a prototype, high-speed CMOS active pixel sensor

    NASA Astrophysics Data System (ADS)

    Zin, Hafiz M.; Harris, Emma J.; Osmond, John P. F.; Allinson, Nigel M.; Evans, Philip M.

    2013-05-01

    This work investigates the feasibility of using a prototype complementary metal oxide semiconductor active pixel sensor (CMOS APS) for real-time verification of volumetric modulated arc therapy (VMAT) treatment. The prototype CMOS APS used region of interest read out on the chip to allow fast imaging of up to 403.6 frames per second (f/s). The sensor was made larger (5.4 cm × 5.4 cm) using recent advances in photolithographic technique but retains fast imaging speed with the sensor's regional read out. There is a paradigm shift in radiotherapy treatment verification with the advent of advanced treatment techniques such as VMAT. This work has demonstrated that the APS can track multi leaf collimator (MLC) leaves moving at 18 mm s-1 with an automatic edge tracking algorithm at accuracy better than 1.0 mm even at the fastest imaging speed. Evaluation of the measured fluence distribution for an example VMAT delivery sampled at 50.4 f/s was shown to agree well with the planned fluence distribution, with an average gamma pass rate of 96% at 3%/3 mm. The MLC leaves motion and linac pulse rate variation delivered throughout the VMAT treatment can also be measured. The results demonstrate the potential of CMOS APS technology as a real-time radiotherapy dosimeter for delivery of complex treatments such as VMAT.

  7. Next-generation CMOS active pixel sensors for satellite hybrid optical communications/imaging sensor systems

    NASA Astrophysics Data System (ADS)

    Stirbl, Robert C.; Pain, Bedabrata; Cunningham, Thomas J.; Hancock, Bruce R.; McCarty, Kenneth P.

    1998-12-01

    Given the current choices of (1) an ever increasing population of large numbers of satellites in low-earth orbit (LEO) constellations for commercial and military global coverage systems, or (2) the alternative of smaller count geosynchronous satellite system constellations in high-earth (HEO), of higher cost and complexity, a number of commercial communications and military operations satellite systems designers are investigating the potential advantages and issues of operating in the mid-earth orbit altitudes (MEO) (between LEO and HEO). At these MEO altitudes both total dose and displacement damage can be traded against the system advantages of fewer satellites required. With growing demand for higher bandwidth communication for real-time earth observing satellite sensor systems, and NASA's interplanetary and deep space virtual unmanned exploration missions in stressing radiation environments, JPL is developing the next generation of smart sensors to address these new requirements of: low-cost, high bandwidth, miniaturization, ultra low-power and mission environment ruggedness. Radiation hardened/tolerant Active Pixel Sensor CMOS imagers that can be adaptively windowed with low power, on-chip control, timing, digital output and provide data-channel efficient on-chip compression, high bandwidth optical communications links are being designed and investigated to reduce size, weight and cost for common optics/hybrid architectures.

  8. Characterization study of an intensified complementary metal-oxide-semiconductor active pixel sensor

    NASA Astrophysics Data System (ADS)

    Griffiths, J. A.; Chen, D.; Turchetta, R.; Royle, G. J.

    2011-03-01

    An intensified CMOS active pixel sensor (APS) has been constructed for operation in low-light-level applications: a high-gain, fast-light decay image intensifier has been coupled via a fiber optic stud to a prototype "VANILLA" APS, developed by the UK based MI3 consortium. The sensor is capable of high frame rates and sparse readout. This paper presents a study of the performance parameters of the intensified VANILLA APS system over a range of image intensifier gain levels when uniformly illuminated with 520 nm green light. Mean-variance analysis shows the APS saturating around 3050 Digital Units (DU), with the maximum variance increasing with increasing image intensifier gain. The system's quantum efficiency varies in an exponential manner from 260 at an intensifier gain of 7.45 × 103 to 1.6 at a gain of 3.93 × 101. The usable dynamic range of the system is 60 dB for intensifier gains below 1.8 × 103, dropping to around 40 dB at high gains. The conclusion is that the system shows suitability for the desired application.

  9. First evidence of phase-contrast imaging with laboratory sources and active pixel sensors

    NASA Astrophysics Data System (ADS)

    Olivo, A.; Arvanitis, C. D.; Bohndiek, S. E.; Clark, A. T.; Prydderch, M.; Turchetta, R.; Speller, R. D.

    2007-11-01

    The aim of the present work is to achieve a first step towards combining the advantages of an innovative X-ray imaging technique—phase-contrast imaging (XPCi)—with those of a new class of sensors, i.e. CMOS-based active pixel sensors (APSs). The advantages of XPCi are well known and include increased image quality and detection of details invisible to conventional techniques, with potential application fields encompassing the medical, biological, industrial and security areas. Vanilla, one of the APSs developed by the MI-3 collaboration (see http://mi3.shef.ac.uk), was thoroughly characterised and an appropriate scintillator was selected to provide X-ray sensitivity. During this process, a set of phase-contrast images of different biological samples was acquired by means of the well-established free-space propagation XPCi technique. The obtained results are very encouraging and are in optimum agreement with the predictions of a simulation recently developed by some of the authors thus further supporting its reliability. This paper presents these preliminary results in detail and discusses in brief both the background to this work and its future developments.

  10. Fabrication issues for silicon backplane active matrix miniature liquid crystal display

    NASA Astrophysics Data System (ADS)

    Underwood, Ian; Burns, D. C.; Rankine, I. D.; Bennett, D. J.; Gourlay, James D.; O'Hara, Anthony; Vass, David G.

    1995-09-01

    We describe a new technology which is appropriate for the production of lightweight, highly compact displays. It is based upon a thin layer of ferroelectric liquid crystal (FLC) on top of, and directly driven by, an active matrix backplane fabricated on single crystal silicon. While devices can be produced using fairly standard techniques, we have developed custon fabrication and packaging techniques, required for optimization of optical quality and performance. We have successfully developed the technology for spatial light modulators for use in applications such as optical correlators and programmable holograms. The FLC is configured in the binary surface stabilized configuration: the CMOS circuits are digital in nature. The device operates in reflection with each pixel having an aluminium pad which acts as a mirror to reflect light and as an electorde to control the state of the overlying FLC. The technology also shows promise as a display technology so we have demonstrated the devices as displays capable of displaying both grey scale and color. We have built FLC devices upon commercially fabricated wafers but have found it advantageous to carry out custom post processing order to improve performance. The main thrust to date has been the use of ECR oxide deposition followed by chemical mechanical polishing to provide an optically flat substrate for mirror deposition. This allows the deposition of flat mirrors which fill almost all of the pixel area; it also allows optimization of the mirror deposition for high optical quality and good FLC alignment. Work is also well advanced on a technique to fill the vias connecting to the mirror layer and on packaging devices to reduce bowing of the silicon and increase the thickness uniformity of the FLC layer. Recent results are demonstrated on LCDs fabricated above two silicon backplanes containing 176 X 176 pixels and 256 X 256 pixels respectively, the former having dynamic signal storage at each pixel, the latter static

  11. Time-Domain Quaternary-Weighted Pulse Width Modulation Driving Method for Active Matrix Organic Light-Emitting Diode Displays

    NASA Astrophysics Data System (ADS)

    Park, Hyun-Sang; Kuk, Seung-Hee; Han, Min-Koo

    2008-03-01

    We proposed a new digital driving method and its pixel structure for active matrix organic light-emitting diode (AMOLED) displays employing time-domain quaternary-weighted pulse width modulation. In the new digital driving method, the luminance of AMOLED displays is accurately determined by averaging photon flux to the desired level over a frame period. The proposed pixel was verified by spice simulation and the output linearity between the grayscale and the OLED current was successfully achieved. In the proposed digital driving pixel, the timing margin was increased and the effect on luminance of AMOLED displays by the troublesome variation of the thin-film transistors (TFTs) was suppressed without additional compensation schemes.

  12. STIS CCD Hot Pixel Annealing

    NASA Astrophysics Data System (ADS)

    Hernandez, Svea

    2013-10-01

    This purpose of this activity is to repair radiation induced hot pixel damage to theSTIS CCD by warming the CCD to the ambient instrument temperature and annealing radiation damaged pixels. Radiation damage creates hot pixels in the STIS CCD Detector. Many of these hot pixels can be repaired by warming the CCD from its normal operating temperature near-83 C to the ambient instrument temperature { +5 C} for several hours. The number of hot pixels repaired is a function of annealing temperature. The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects.

  13. Simulation of active-edge pixelated CdTe radiation detectors

    NASA Astrophysics Data System (ADS)

    Duarte, D. D.; Lipp, J. D.; Schneider, A.; Seller, P.; Veale, M. C.; Wilson, M. D.; Baker, M. A.; Sellin, P. J.

    2016-01-01

    The edge surfaces of single crystal CdTe play an important role in the electronic properties and performance of this material as an X-ray and γ-ray radiation detector. Edge effects have previously been reported to reduce the spectroscopic performance of the edge pixels in pixelated CdTe radiation detectors without guard bands. A novel Technology Computer Aided Design (TCAD) model based on experimental data has been developed to investigate these effects. The results presented in this paper show how localized low resistivity surfaces modify the internal electric field of CdTe creating potential wells. These result in a reduction of charge collection efficiency of the edge pixels, which compares well with experimental data.

  14. Smart pixels

    NASA Astrophysics Data System (ADS)

    Seitz, Peter

    2004-09-01

    Semiconductor technology progresses at a relentless pace, making it possible to provide image sensors and each pixel with an increasing amount of custom analog and digital functionality. As experience with such photosensor functionality grows, an increasing variety of modular building blocks become available for smart pixels, single-chip digital cameras and functional image sensors. Examples include a non-linear pixel response circuit for high-dynamic range imaging with a dynamic range exceeding 180 dB, low-noise amplifiers and avalanche-effect pixels for high-sensitivity detection performance approaching single-photoelectron resolution, lock-in pixels for optical time-of-flight range cameras with sub-centimeter distance resolution and in-pixel demodulation circuits for optical coherence tomography imaging. The future is seen in system-on-a-chip machine vision cameras ("seeing chips"), post-processing with non-silicon materials for the extension of the detection range to the X-ray, ultraviolet and infrared spectrum, the use of organic semiconductors for low-cost large-area photonic microsystems, as well as imaging of fields other than electromagnetic radiation.

  15. Thin n-in-p planar pixel sensors and active edge sensors for the ATLAS upgrade at HL-LHC

    NASA Astrophysics Data System (ADS)

    Terzo, S.; Macchiolo, A.; Nisius, R.; Paschen, B.

    2014-12-01

    Silicon pixel modules employing n-in-p planar sensors with an active thickness of 200 μm, produced at CiS, and 100-200 μm thin active/slim edge sensor devices, produced at VTT in Finland have been interconnected to ATLAS FE-I3 and FE-I4 read-out chips. The thin sensors are designed for high energy physics collider experiments to ensure radiation hardness at high fluences. Moreover, the active edge technology of the VTT production maximizes the sensitive region of the assembly, allowing for a reduced overlap of the modules in the pixel layer close to the beam pipe. The CiS production includes also four chip sensors according to the module geometry planned for the outer layers of the upgraded ATLAS pixel detector to be operated at the HL-LHC. The modules have been characterized using radioactive sources in the laboratory and with high precision measurements at beam tests to investigate the hit efficiency and charge collection properties at different bias voltages and particle incidence angles. The performance of the different sensor thicknesses and edge designs are compared before and after irradiation up to a fluence of 1.4 × 1016 neq/cm2.

  16. PIXEL PUSHER

    NASA Technical Reports Server (NTRS)

    Stanfill, D. F.

    1994-01-01

    Pixel Pusher is a Macintosh application used for viewing and performing minor enhancements on imagery. It will read image files in JPL's two primary image formats- VICAR and PDS - as well as the Macintosh PICT format. VICAR (NPO-18076) handles an array of image processing capabilities which may be used for a variety of applications including biomedical image processing, cartography, earth resources, and geological exploration. Pixel Pusher can also import VICAR format color lookup tables for viewing images in pseudocolor (256 colors). This program currently supports only eight bit images but will work on monitors with any number of colors. Arbitrarily large image files may be viewed in a normal Macintosh window. Color and contrast enhancement can be performed with a graphical "stretch" editor (as in contrast stretch). In addition, VICAR images may be saved as Macintosh PICT files for exporting into other Macintosh programs, and individual pixels can be queried to determine their locations and actual data values. Pixel Pusher is written in Symantec's Think C and was developed for use on a Macintosh SE30, LC, or II series computer running System Software 6.0.3 or later and 32 bit QuickDraw. Pixel Pusher will only run on a Macintosh which supports color (whether a color monitor is being used or not). The standard distribution medium for this program is a set of three 3.5 inch Macintosh format diskettes. The program price includes documentation. Pixel Pusher was developed in 1991 and is a copyrighted work with all copyright vested in NASA. Think C is a trademark of Symantec Corporation. Macintosh is a registered trademark of Apple Computer, Inc.

  17. A Real-time Auto-detection Method for Random Telegraph Signal (RTS) Noise Detection in CMOS Active pixel sensors

    NASA Astrophysics Data System (ADS)

    Zheng, R.; Zhao, R.; Ma, Y.; Li, B.; Wei, X.; Wang, J.; Gao, W.; Wei, T.; Gao, D.; Hu, Y.

    2015-07-01

    CMOS Active pixel sensors (CMOS APS) are attractive for use in the innermost layers of charged particle trackers, due to their good tradeoffs among the key performances. However, CMOS APS can be greatly influenced by random telegraph signal (RTS) noise, which can cause particle tracking or energy calculation failures. In-depth research of pixels' RTS behavior stimulates the interest of the methods for RTS noise detection, reconstruction and parameters extraction. In this paper, a real-time auto-detection method is proposed, using real-time Gaussian noise standard deviation as the detection threshold. Experimental results show that, compared with current methods using signal standard deviation as the thresholds, the proposed method is more sensitive in multi-level RTS detection and more effective in the case of RTS noise degradation.

  18. Thin active region, type II superlattice photodiode arrays: Single-pixel and focal plane array characterization

    NASA Astrophysics Data System (ADS)

    Little, J. W.; Svensson, S. P.; Beck, W. A.; Goldberg, A. C.; Kennerly, S. W.; Hongsmatip, T.; Winn, M.; Uppal, P.

    2007-02-01

    We have measured the radiometric properties of two midwave infrared photodiode arrays (320×256pixel2 format) fabricated from the same wafer comprising a thin (0.24μm), not intentionally doped InAs /GaSb superlattice between a p-doped GaSb layer and a n-doped InAs layer. One of the arrays was indium bump bonded to a silicon fanout chip to allow for the measurement of properties of individual pixels, and one was bonded to a readout integrated circuit to enable array-scale measurements and infrared imaging. The superlattice layer is thin enough that it is fully depleted at zero bias, and the collection efficiency of photogenerated carriers in the intrinsic region is close to unity. This simplifies the interpretation of photocurrent data as compared with previous measurements made on thick superlattices with complex doping profiles. Superlattice absorption coefficient curves, obtained from measurements of the external quantum efficiency using two different assumptions for optical coupling into the chip, bracket values calculated using an eight-band k •p model. Measurements of the quantum efficiency map of the focal plane array were in good agreement with the single-pixel measurements. Imagery obtained with this focal plane array demonstrates the high uniformity and crystal quality of the type II superlattice material.

  19. Pixel Paradise

    NASA Technical Reports Server (NTRS)

    1998-01-01

    PixelVision, Inc., has developed a series of integrated imaging engines capable of high-resolution image capture at dynamic speeds. This technology was used originally at Jet Propulsion Laboratory in a series of imaging engines for a NASA mission to Pluto. By producing this integrated package, Charge-Coupled Device (CCD) technology has been made accessible to a wide range of users.

  20. Imaging of moving fiducial markers during radiotherapy using a fast, efficient active pixel sensor based EPID

    SciTech Connect

    Osmond, John P. F.; Zin, Hafiz M.; Harris, Emma J.; Lupica, Giovanni; Allinson, Nigel M.; Evans, Philip M.

    2011-11-15

    Purpose: The purpose of this work was to investigate the use of an experimental complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) for tracking of moving fiducial markers during radiotherapy. Methods: The APS has an active area of 5.4 x 5.4 cm and maximum full frame read-out rate of 20 frame s{sup -1}, with the option to read out a region-of-interest (ROI) at an increased rate. It was coupled to a 4 mm thick ZnWO4 scintillator which provided a quantum efficiency (QE) of 8% for a 6 MV x-ray treatment beam. The APS was compared with a standard iViewGT flat panel amorphous Silicon (a-Si) electronic portal imaging device (EPID), with a QE of 0.34% and a frame-rate of 2.5 frame s{sup -1}. To investigate the ability of the two systems to image markers, four gold cylinders of length 8 mm and diameter 0.8, 1.2, 1.6, and 2 mm were placed on a motion-platform. Images of the stationary markers were acquired using the APS at a frame-rate of 20 frame s{sup -1}, and a dose-rate of 143 MU min{sup -1} to avoid saturation. EPID images were acquired at the maximum frame-rate of 2.5 frame s{sup -1}, and a reduced dose-rate of 19 MU min{sup -1} to provide a similar dose per frame to the APS. Signal-to-noise ratio (SNR) of the background signal and contrast-to-noise ratio (CNR) of the marker signal relative to the background were evaluated for both imagers at doses of 0.125 to 2 MU. Results: Image quality and marker visibility was found to be greater in the APS with SNR {approx}5 times greater than in the EPID and CNR up to an order of magnitude greater for all four markers. To investigate the ability to image and track moving markers the motion-platform was moved to simulate a breathing cycle with period 6 s, amplitude 20 mm and maximum speed 13.2 mm s{sup -1}. At the minimum integration time of 50 ms a tracking algorithm applied to the APS data found all four markers with a success rate of {>=}92% and positional error {<=}90 {mu}m. At an integration time of 400

  1. Equivalence of a Bit Pixel Image to a Quantum Pixel Image

    NASA Astrophysics Data System (ADS)

    Ortega, Laurel Carlos; Dong, Shi-Hai; Cruz-Irisson, M.

    2015-11-01

    We propose a new method to transform a pixel image to the corresponding quantum-pixel using a qubit per pixel to represent each pixels classical weight in a quantum image matrix weight. All qubits are linear superposition, changing the coefficients level by level to the entire longitude of the gray scale with respect to the base states of the qubit. Classically, these states are just bytes represented in a binary matrix, having code combinations of 1 or 0 at all pixel locations. This method introduces a qubit-pixel image representation of images captured by classical optoelectronic methods. Supported partially by the project 20150964-SIP-IPN, Mexico

  2. Active pixel sensors in AMS H18/H35 HV-CMOS technology for the ATLAS HL-LHC upgrade

    NASA Astrophysics Data System (ADS)

    Ristic, Branislav

    2016-09-01

    Deep sub micron HV-CMOS processes offer the opportunity for sensors built by industry standard techniques while being HV tolerant, making them good candidates for drift-based, fast collecting, thus radiation-hard pixel detectors. For the upgrade of the ATLAS Pixel Detector towards the HL-LHC requirements, active pixel sensors in HV-CMOS technology were investigated. These implement signal processing electronics in deep n-wells, which also act as collecting electrodes. The deep n-wells allow for bias voltages up to 150 V leading to a depletion depth of several 10 μm. Prototype sensors in the AMS H18 180 nm and H35 350 nm HV-CMOS processes were thoroughly tested in lab measurements as well as in testbeam experiments. Irradiations with X-rays and protons revealed a tolerance to ionizing doses of 1 Grad while Edge-TCT studies assessed the effects of radiation on the charge collection. The sensors showed high detection efficiencies after neutron irradiation to 1015neq cm-2 in testbeam experiments. A full reticle size demonstrator chip, implemented in the H35 process is being submitted to prove the large scale feasibility of the HV-CMOS concept.

  3. Pixel Perfect

    SciTech Connect

    Perrine, Kenneth A.; Hopkins, Derek F.; Lamarche, Brian L.; Sowa, Marianne B.

    2005-09-01

    Biologists and computer engineers at Pacific Northwest National Laboratory have specified, designed, and implemented a hardware/software system for performing real-time, multispectral image processing on a confocal microscope. This solution is intended to extend the capabilities of the microscope, enabling scientists to conduct advanced experiments on cell signaling and other kinds of protein interactions. FRET (fluorescence resonance energy transfer) techniques are used to locate and monitor protein activity. In FRET, it is critical that spectral images be precisely aligned with each other despite disturbances in the physical imaging path caused by imperfections in lenses and cameras, and expansion and contraction of materials due to temperature changes. The central importance of this work is therefore automatic image registration. This runs in a framework that guarantees real-time performance (processing pairs of 1024x1024, 8-bit images at 15 frames per second) and enables the addition of other types of advanced image processing algorithms such as image feature characterization. The supporting system architecture consists of a Visual Basic front-end containing a series of on-screen interfaces for controlling various aspects of the microscope and a script engine for automation. One of the controls is an ActiveX component written in C++ for handling the control and transfer of images. This component interfaces with a pair of LVDS image capture boards and a PCI board containing a 6-million gate Xilinx Virtex-II FPGA. Several types of image processing are performed on the FPGA in a pipelined fashion, including the image registration. The FPGA offloads work that would otherwise need to be performed by the main CPU and has a guaranteed real-time throughput. Image registration is performed in the FPGA by applying a cubic warp on one image to precisely align it with the other image. Before each experiment, an automated calibration procedure is run in order to set up the

  4. Non-linear responsivity characterisation of a CMOS Active Pixel Sensor for high resolution imaging of the Jovian system

    NASA Astrophysics Data System (ADS)

    Soman, M.; Stefanov, K.; Weatherill, D.; Holland, A.; Gow, J.; Leese, M.

    2015-02-01

    The Jovian system is the subject of study for the Jupiter Icy Moon Explorer (JUICE), an ESA mission which is planned to launch in 2022. The scientific payload is designed for both characterisation of the magnetosphere and radiation environment local to the spacecraft, as well as remote characterisation of Jupiter and its satellites. A key instrument on JUICE is the high resolution and wide angle camera, JANUS, whose main science goals include detailed characterisation and study phases of three of the Galilean satellites, Ganymede, Callisto and Europa, as well as studies of other moons, the ring system, and irregular satellites. The CIS115 is a CMOS Active Pixel Sensor from e2v technologies selected for the JANUS camera. It is fabricated using 0.18 μ m CMOS imaging sensor process, with an imaging area of 2000 × 1504 pixels, each 7 μ m square. A 4T pixel architecture allows for efficient correlated double sampling, improving the readout noise to better than 8 electrons rms, whilst the sensor is operated in a rolling shutter mode, sampling at up to 10 Mpixel/s at each of the four parallel outputs.A primary parameter to characterise for an imaging device is the relationship that converts the sensor's voltage output back to the corresponding number of electrons that were detected in a pixel, known as the Charge to Voltage Factor (CVF). In modern CMOS sensors with small feature sizes, the CVF is known to be non-linear with signal level, therefore a signal-dependent measurement of the CIS115's CVF has been undertaken and is presented here. The CVF is well modelled as a quadratic function leading to a measurement of the maximum charge handling capacity of the CIS115 to be 3.4 × 104 electrons. If the CIS115's response is assumed linear, its CVF is 21.1 electrons per mV (1/47.5 μ V per electron).

  5. The RD50 activity in the context of future pixel detector systems

    NASA Astrophysics Data System (ADS)

    Casse, G.

    2015-05-01

    The CERN/RD50 collaboration is dedicated to the radiation hardening of semiconductor sensors for future super-collider needs. The findings of this collaboration are therefore especially relevant to the pixel devices for the LHC experiment upgrades. A considerable amount of results on the enhancement of the radiation tolerance of silicon sensors has been found within RD50. The research towards radiation hardening has highlighted, and increased the knowledge on properties of sensors that are relevant to other applications. For example radiation hardening relies on the speed of signal collection in irradiated devices. As a consequence, the methods envisaged for increasing this collection speed turn out to be promising for significantly improving the performance of time resolved, high spatial resolution systems. A new type of device processing strongly emerging for production of future pixel sensor systems is the HV-CMOS technology. The RD50 research methodology provides the tools for characterising the behaviour of the deep collecting electrode (deep n-well) for this type of device after irradiation and the optimal framework for comparing the performance of the new devices with the current state of the art.

  6. A High-Speed, Event-Driven, Active Pixel Sensor Readout for Photon-Counting Microchannel Plate Detectors

    NASA Technical Reports Server (NTRS)

    Kimble, Randy A.; Pain, Bedabrata; Norton, Timothy J.; Haas, J. Patrick; Oegerle, William R. (Technical Monitor)

    2002-01-01

    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 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 of 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.

  7. 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.

  8. Planarization coating for polyimide substrates used in roll-to-roll fabrication of active matrix backplanes for flexible displays

    NASA Astrophysics Data System (ADS)

    Almanza-Workman, A. Marcia; Jeans, Albert; Braymen, Steve; Elder, Richard E.; Garcia, Robert A.; de la Fuente Vornbrock, Alejandro; Hauschildt, Jason; Holland, Edward; Jackson, Warren; Jam, Mehrban; Jeffrey, Frank; Junge, Kelly; Kim, Han-Jun; Kwon, Ohseung; Larson, Don; Luo, Hao; Maltabes, John; Mei, Ping; Perlov, Craig; Smith, Mark; Stieler, Dan; Taussig, Carl P.; Trovinger, Steve; Zhao, Lihua

    2012-03-01

    Good surface quality of plastic substrates is essential to reduce pixel defects during roll-to-roll fabrication of flexible display active matrix backplanes. Standard polyimide substrates have a high density of "bumps" from fillers and belt marks and other defects from dust and surface scratching. Some of these defects could be the source of shunts in dielectrics. The gate dielectric must prevent shorts between the source/drain and the gate in the transistors, resist shorts in the hold capacitor and stop shorts in the data/gate line crossovers in active matrix backplanes fabricated by self-aligned imprint lithography (SAIL) roll-to-roll processes. Otherwise data and gate lines will become shorted creating line or pixel defects. In this paper, we discuss the development of a proprietary UV curable planarization material that can be coated by roll-to-roll processes. This material was engineered to have low shrinkage, excellent adhesion to polyimide, high dry etch resistance, and great chemical and thermal stability. Results from PECVD deposition of an amorphous silicon stack on the planarized polyimide and compatibility with roll-to-roll processes to fabricate active matrix backplanes are also discussed. The effect of the planarization on defects in the stack, shunts in the dielectric and curvature of finished arrays will also be described.

  9. Low-Voltage, Low-Power, Organic Light-Emitting Transistors for Active Matrix Displays

    NASA Astrophysics Data System (ADS)

    McCarthy, M. A.; Liu, B.; Donoghue, E. P.; Kravchenko, I.; Kim, D. Y.; So, F.; Rinzler, A. G.

    2011-04-01

    Intrinsic nonuniformity in the polycrystalline-silicon backplane transistors of active matrix organic light-emitting diode displays severely limits display size. Organic semiconductors might provide an alternative, but their mobility remains too low to be useful in the conventional thin-film transistor design. Here we demonstrate an organic channel light-emitting transistor operating at low voltage, with low power dissipation, and high aperture ratio, in the three primary colors. The high level of performance is enabled by a single-wall carbon nanotube network source electrode that permits integration of the drive transistor and the light emitter into an efficient single stacked device. The performance demonstrated is comparable to that of polycrystalline-silicon backplane transistor-driven display pixels.

  10. ZnO:H indium-free transparent conductive electrodes for active-matrix display applications

    NASA Astrophysics Data System (ADS)

    Chen, Shuming; Wang, Sisi

    2014-12-01

    Transparent conductive electrodes based on hydrogen (H)-doped zinc oxide (ZnO) have been proposed for active-matrix (AM) display applications. When fabricated with optimal H plasma power and optimal plasma treatment time, the resulting ZnO:H films exhibit low sheet resistance of 200 Ω/◻ and high average transmission of 85% at a film thickness of 150 nm. The demonstrated transparent conductive ZnO:H films can potentially replace indium-tin-oxide and serve as pixel electrodes for organic light-emitting diodes as well as source/drain electrodes for ZnO-based thin-film transistors. Use of the proposed ZnO:H electrodes means that two photomask stages can be removed from the fabrication process flow for ZnO-based AM backplanes.

  11. ZnO:H indium-free transparent conductive electrodes for active-matrix display applications

    SciTech Connect

    Chen, Shuming Wang, Sisi

    2014-12-01

    Transparent conductive electrodes based on hydrogen (H)-doped zinc oxide (ZnO) have been proposed for active-matrix (AM) display applications. When fabricated with optimal H plasma power and optimal plasma treatment time, the resulting ZnO:H films exhibit low sheet resistance of 200 Ω/◻ and high average transmission of 85% at a film thickness of 150 nm. The demonstrated transparent conductive ZnO:H films can potentially replace indium-tin-oxide and serve as pixel electrodes for organic light-emitting diodes as well as source/drain electrodes for ZnO-based thin-film transistors. Use of the proposed ZnO:H electrodes means that two photomask stages can be removed from the fabrication process flow for ZnO-based AM backplanes.

  12. Synchrotron based planar imaging and digital tomosynthesis of breast and biopsy phantoms using a CMOS active pixel sensor.

    PubMed

    Szafraniec, Magdalena B; Konstantinidis, Anastasios C; Tromba, Giuliana; Dreossi, Diego; Vecchio, Sara; Rigon, Luigi; Sodini, Nicola; Naday, Steve; Gunn, Spencer; McArthur, Alan; Olivo, Alessandro

    2015-03-01

    The SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline at Elettra is performing the first mammography study on human patients using free-space propagation phase contrast imaging. The stricter spatial resolution requirements of this method currently force the use of conventional films or specialized computed radiography (CR) systems. This also prevents the implementation of three-dimensional (3D) approaches. This paper explores the use of an X-ray detector based on complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology as a possible alternative, for acquisitions both in planar and tomosynthesis geometry. Results indicate higher quality of the images acquired with the synchrotron set-up in both geometries. This improvement can be partly ascribed to the use of parallel, collimated and monochromatic synchrotron radiation (resulting in scatter rejection, no penumbra-induced blurring and optimized X-ray energy), and partly to phase contrast effects. Even though the pixel size of the used detector is still too large - and thus suboptimal - for free-space propagation phase contrast imaging, a degree of phase-induced edge enhancement can clearly be observed in the images. PMID:25498332

  13. Performance of a-Si:H photodiode technology-based advanced CMOS active pixel sensor imagers

    NASA Astrophysics Data System (ADS)

    Theil, Jeremy A.; Haddad, Homayoon; Snyder, Rick D.; Zelman, Mike; Hula, David; Lindahl, Kirk A.

    2001-12-01

    Amorphous silicon photodiode technology is a very attractive option for image array integrated circuits because it enables large die-size reduction and higher light collection efficiency than c-Si arrays. The concept behind the technology is to place the photosensing element directly above the rest of the circuit, thus eliminating the need to make areal tradeoffs between photodiode and pixel circuit. We have developed an photodiode array technology that is fully compatible with a 0.35 um CMOS process to produce image sensors arrays with 10-bit dynamic range that are 30% smaller than comparable c-Si photodiode arrays. The work presented here will discuss performance issues and solutions to lend itself to cost-effective high-volume manufacturing. The various methods of interconnection of the diode to the array and their advantages will be presented. The effect of doped layer thickness and concentration on quantum efficiency, and the effect of a-Si:H defect concentration on diode performance will be discussed. The photodiode dark leakage current density is about 80 pA/cm2, and its absolute quantum efficiency peaks about 85% at 550 nm. These sensors have 50% higher sensitivity, and 2x lower dark current when compared to bulk silicon sensors of the same design. The cell utilizes a 3 FET design, but allows for 100% photodiode area due to the elevated nature of the design. The VGA (640 X 480), array demonstrated here uses common intrinsic and p-type contact layers, and makes reliable contact to those layers by use of a monolithic transparent conductor strap tied to vias in the interconnect.

  14. Cellular contractility and extracellular matrix stiffness regulate matrix metalloproteinase activity in pancreatic cancer cells.

    PubMed

    Haage, Amanda; Schneider, Ian C

    2014-08-01

    The pathogenesis of cancer is often driven by local invasion and metastasis. Recently, mechanical properties of the tumor microenvironment have been identified as potent regulators of invasion and metastasis, while matrix metalloproteinases (MMPs) are classically known as significant enhancers of cancer cell migration and invasion. Here we have been able to sensitively measure MMP activity changes in response to specific extracellular matrix (ECM) environments and cell contractility states. Cells of a pancreatic cancer cell line, Panc-1, up-regulate MMP activities between 3- and 10-fold with increased cell contractility. Conversely, they down-regulate MMP activities when contractility is blocked to levels seen with pan-MMP activity inhibitors. Similar, albeit attenuated, responses are seen in other pancreatic cancer cell lines, BxPC-3 and AsPC-1. In addition, MMP activity was modulated by substrate stiffness, collagen gel concentration, and the degree of collagen cross-linking, when cells were plated on collagen gels ranging from 0.5 to 5 mg/ml that span the physiological range of substrate stiffness (50-2000 Pa). Panc-1 cells showed enhanced MMP activity on stiffer substrates, whereas BxPC-3 and AsPC-1 cells showed diminished MMP activity. In addition, eliminating heparan sulfate proteoglycans using heparinase completely abrogated the mechanical induction of MMP activity. These results demonstrate the first functional link between MMP activity, contractility, and ECM stiffness and provide an explanation as to why stiffer environments result in enhanced cell migration and invasion.

  15. Google matrix of the world network of economic activities

    NASA Astrophysics Data System (ADS)

    Kandiah, Vivek; Escaith, Hubert; Shepelyansky, Dima L.

    2015-07-01

    Using the new data from the OECD-WTO world network of economic activities we construct the Google matrix G of this directed network and perform its detailed analysis. The network contains 58 countries and 37 activity sectors for years 1995 and 2008. The construction of G, based on Markov chain transitions, treats all countries on equal democratic grounds while the contribution of activity sectors is proportional to their exchange monetary volume. The Google matrix analysis allows to obtain reliable ranking of countries and activity sectors and to determine the sensitivity of CheiRank-PageRank commercial balance of countries in respect to price variations and labor cost in various countries. We demonstrate that the developed approach takes into account multiplicity of network links with economy interactions between countries and activity sectors thus being more efficient compared to the usual export-import analysis. The spectrum and eigenstates of G are also analyzed being related to specific activity communities of countries.

  16. Imaging properties of pixellated scintillators with deep pixels

    NASA Astrophysics Data System (ADS)

    Barber, H. Bradford; Fastje, David; Lemieux, Daniel; Grim, Gary P.; Furenlid, Lars R.; Miller, Brian W.; Parkhurst, Philip; Nagarkar, Vivek V.

    2014-09-01

    We have investigated the light-transport properties of scintillator arrays with long, thin pixels (deep pixels) for use in high-energy gamma-ray imaging. We compared 10x10 pixel arrays of YSO:Ce, LYSO:Ce and BGO (1mm x 1mm x 20 mm pixels) made by Proteus, Inc. with similar 10x10 arrays of LSO:Ce and BGO (1mm x 1mm x 15mm pixels) loaned to us by Saint-Gobain. The imaging and spectroscopic behaviors of these scintillator arrays are strongly affected by the choice of a reflector used as an inter-pixel spacer (3M ESR in the case of the Proteus arrays and white, diffuse-reflector for the Saint-Gobain arrays). We have constructed a 3700-pixel LYSO:Ce Prototype NIF Gamma-Ray Imager for use in diagnosing target compression in inertial confinement fusion. This system was tested at the OMEGA Laser and exhibited significant optical, inter-pixel cross-talk that was traced to the use of a single-layer of ESR film as an inter-pixel spacer. We show how the optical cross-talk can be mapped, and discuss correction procedures. We demonstrate a 10x10 YSO:Ce array as part of an iQID (formerly BazookaSPECT) imager and discuss issues related to the internal activity of 176Lu in LSO:Ce and LYSO:Ce detectors.

  17. A data parallel digitizer for a time-based simulation of CMOS Monolithic Active Pixel Sensors with FairRoot

    NASA Astrophysics Data System (ADS)

    Sitzmann, P.; Amar-Youcef, S.; Doering, D.; Deveaux, M.; Fröhlich, I.; Koziel, M.; Krebs, E.; Linnik, B.; Michel, J.; Milanovic, B.; Müntz, C.; Li, Q.; Stroth, J.; Tischler, T.

    2014-06-01

    CMOS Monolithic Active Pixel Sensors (MAPS) demonstrated excellent performances in the field of charged particle tracking. They feature an excellent single point resolution of few μm, a light material budget of 0.05% Xo in combination with a good radiation tolerance and time resolution. This makes the sensors a valuable technology for micro vertex detectors (MVD) of various experiments in heavy ion and particle physics like STAR and CBM. State of the art MAPS are equipped with a rolling shutter readout. Therefore, the data of one individual event is typically found in more than one data train generated by the sensor. This paper presents a concept to introduce this feature in both simulation and data analysis, taking profit of the sensor topology of the MVD. This topology allows to use for massive parallel data streaming and handling strategies within the FairRoot framework.

  18. First use of a high-sensitivity active pixel sensor array as a detector for electron microscopy

    NASA Astrophysics Data System (ADS)

    Xuong, Nguyen-Huu; Milazzo, Anna-Clare; LeBlanc, Philippe; Duttweiler, Fred; Bouwer, James; Peltier, Steve; Ellisman, Mark; Denes, Peter; Bieser, Fred; Matis, Howard S.; Wieman, Howard; Kleinfelder, Stuart

    2004-06-01

    There is an urgent need to replace film and CCD cameras as recording instruments for transmission electron microscopy (TEM). Film is too cumbersome to process and CCD cameras have low resolution, marginal to poor signal-to-noise ratio for single electron detection and high spatial distortion. To find a replacement device, we have tested a high sensitivity active pixel sensor (APS) array currently being developed for nuclear physics. The tests were done at 120 keV in a JEOL 1200 electron microscope. At this energy, each electron produced on average a signal-tonoise ratio about 20/1. The spatial resolution was also excellent with the full width at half maximum (FWHM) about 20 microns. Since it is very radiation tolerant and has almost no spatial distortion, the above tests showed that a high sensitivity CMOS APS array holds great promise as a direct detection device for electron microscopy.

  19. Active hyperspectral imaging using a quantum cascade laser (QCL) array and digital-pixel focal plane array (DFPA) camera.

    PubMed

    Goyal, Anish; Myers, Travis; Wang, Christine A; Kelly, Michael; Tyrrell, Brian; Gokden, B; Sanchez, Antonio; Turner, George; Capasso, Federico

    2014-06-16

    We demonstrate active hyperspectral imaging using a quantum-cascade laser (QCL) array as the illumination source and a digital-pixel focal-plane-array (DFPA) camera as the receiver. The multi-wavelength QCL array used in this work comprises 15 individually addressable QCLs in which the beams from all lasers are spatially overlapped using wavelength beam combining (WBC). The DFPA camera was configured to integrate the laser light reflected from the sample and to perform on-chip subtraction of the passive thermal background. A 27-frame hyperspectral image was acquired of a liquid contaminant on a diffuse gold surface at a range of 5 meters. The measured spectral reflectance closely matches the calculated reflectance. Furthermore, the high-speed capabilities of the system were demonstrated by capturing differential reflectance images of sand and KClO3 particles that were moving at speeds of up to 10 m/s.

  20. Measurements and simulations of MAPS (Monolithic Active Pixel Sensors) response to charged particles - a study towards a vertex detector at the ILC

    NASA Astrophysics Data System (ADS)

    Maczewski, Lukasz

    2010-05-01

    The International Linear Collider (ILC) is a project of an electron-positron (e+e-) linear collider with the centre-of-mass energy of 200-500 GeV. Monolithic Active Pixel Sensors (MAPS) are one of the proposed silicon pixel detector concepts for the ILC vertex detector (VTX). Basic characteristics of two MAPS pixel matrices MIMOSA-5 (17 μm pixel pitch) and MIMOSA-18 (10 μm pixel pitch) are studied and compared (pedestals, noises, calibration of the ADC-to-electron conversion gain, detector efficiency and charge collection properties). The e+e- collisions at the ILC will be accompanied by intense beamsstrahlung background of electrons and positrons hitting inner planes of the vertex detector. Tracks of this origin leave elongated clusters contrary to those of secondary hadrons. Cluster characteristics and orientation with respect to the pixels netting are studied for perpendicular and inclined tracks. Elongation and precision of determining the cluster orientation as a function of the angle of incidence were measured. A simple model of signal formation (based on charge diffusion) is proposed and tested using the collected data.

  1. Sparse matrix approximation method for an active optical control system

    NASA Astrophysics Data System (ADS)

    Murphy, Timothy P.; Lyon, Richard G.; Dorband, John E.; Hollis, Jan M.

    2001-12-01

    We develop a sparse matrix approximation method to decompose a wave front into a basis set of actuator influence functions for an active optical system consisting of a deformable mirror and a segmented primary mirror. The wave front used is constructed by Zernike polynomials to simulate the output of a phase-retrieval algorithm. Results of a Monte Carlo simulation of the optical control loop are compared with the standard, nonsparse approach in terms of accuracy and precision, as well as computational speed and memory. The sparse matrix approximation method can yield more than a 50-fold increase in the speed and a 20-fold-reduction in matrix size and a commensurate decrease in required memory, with less than 10% degradation in solution accuracy. Our method is also shown to be better than when elements are selected for the sparse matrix on a magnitude basis alone. We show that the method developed is a viable alternative to use of the full control matrix in a phase-retrieval-based active optical control system.

  2. Sparse matrix approximation method for an active optical control system.

    PubMed

    Murphy, T P; Lyon, R G; Dorband, J E; Hollis, J M

    2001-12-10

    We develop a sparse matrix approximation method to decompose a wave front into a basis set of actuator influence functions for an active optical system consisting of a deformable mirror and a segmented primary mirror. The wave front used is constructed by Zernike polynomials to simulate the output of a phase-retrieval algorithm. Results of a Monte Carlo simulation of the optical control loop are compared with the standard, nonsparse approach in terms of accuracy and precision, as well as computational speed and memory. The sparse matrix approximation method can yield more than a 50-fold increase in the speed and a 20-fold reduction in matrix size and a commensurate decrease in required memory, with less than 10% degradation in solution accuracy. Our method is also shown to be better than when elements are selected for the sparse matrix on a magnitude basis alone. We show that the method developed is a viable alternative to use of the full control matrix in a phase-retrieval-based active optical control system. PMID:18364958

  3. Current-Sensing and Voltage-Feedback Driving Method for Large-Area High-Resolution Active Matrix Organic Light Emitting Diodes

    NASA Astrophysics Data System (ADS)

    In, Hai‑Jung; Choi, Byong‑Deok; Chung, Ho‑Kyoon; Kwon, Oh‑Kyong

    2006-05-01

    There is the problem of picture quality nonuniformity due to thin film transistor (TFT) characteristic variations throughout a panel of large-area high-resolution active matrix organic light emitting diodes. The current programming method could solve this issue, but it also requires very long charging time of a data line at low gray shades. Therefore, we propose a new driving method and a pixel circuit with emission-current sensing and feedback operation in order to resolve these problems. The proposed driving method and pixel circuit successfully compensate threshold voltage and mobility variations of TFTs and overcome the data line charging problem. Simulation results show that emission current deviations of the proposed driving method are less than 1.7% with ± 10.0% mobility and ± 0.3 V threshold voltage variations of pixel-driving TFTs, which means the proposed driving method is applicable to large-area high-resolution applications.

  4. Large area CMOS active pixel sensor x-ray imager for digital breast tomosynthesis: Analysis, modeling, and characterization

    SciTech Connect

    Zhao, Chumin; Kanicki, Jerzy; Konstantinidis, Anastasios C.; Patel, Tushita

    2015-11-15

    Purpose: Large area x-ray imagers based on complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology have been proposed for various medical imaging applications including digital breast tomosynthesis (DBT). The low electronic noise (50–300 e{sup −}) of CMOS APS x-ray imagers provides a possible route to shrink the pixel pitch to smaller than 75 μm for microcalcification detection and possible reduction of the DBT mean glandular dose (MGD). Methods: In this study, imaging performance of a large area (29 × 23 cm{sup 2}) CMOS APS x-ray imager [Dexela 2923 MAM (PerkinElmer, London)] with a pixel pitch of 75 μm was characterized and modeled. The authors developed a cascaded system model for CMOS APS x-ray imagers using both a broadband x-ray radiation and monochromatic synchrotron radiation. The experimental data including modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE) were theoretically described using the proposed cascaded system model with satisfactory consistency to experimental results. Both high full well and low full well (LFW) modes of the Dexela 2923 MAM CMOS APS x-ray imager were characterized and modeled. The cascaded system analysis results were further used to extract the contrast-to-noise ratio (CNR) for microcalcifications with sizes of 165–400 μm at various MGDs. The impact of electronic noise on CNR was also evaluated. Results: The LFW mode shows better DQE at low air kerma (K{sub a} < 10 μGy) and should be used for DBT. At current DBT applications, air kerma (K{sub a} ∼ 10 μGy, broadband radiation of 28 kVp), DQE of more than 0.7 and ∼0.3 was achieved using the LFW mode at spatial frequency of 0.5 line pairs per millimeter (lp/mm) and Nyquist frequency ∼6.7 lp/mm, respectively. It is shown that microcalcifications of 165–400 μm in size can be resolved using a MGD range of 0.3–1 mGy, respectively. In comparison to a General Electric GEN2 prototype DBT system (at

  5. A 70μm × 70μm CMOS digital active pixel sensor for digital mammography and X-ray imaging

    NASA Astrophysics Data System (ADS)

    Sabadell, J.; Figueras, R.; Margarit, J. M.; Martín, E.; Terès, L.; Serra-Graells, F.

    2011-03-01

    This work presents an architecture for CMOS active pixel sensors (APS) based on a novel lossless charge integration method, proposed for X-ray imagers in general but specifically optimized for full-field digital mammography. The objective is to provide all the required functionality inside the pixel, so to use full digital control and read-out signals only, therefore avoiding crosstalk between analog lines over large pixel arrays. It includes a novel lossless A/D conversion scheme besides a self-calibrating dark current cancellation circuit, a self-biasing circuitry, biphasic current sensing for the collection of electrons (e-) or holes (h+) and built-in test. Furthermore, FPN compensation is available by individually addressing the pixel's internal DAC controlling the gain. Implemented in a 0.18μm 1P6M CMOS technology with MiM capacitors, everything fits into a 70μm by 70μm due to the extensive reuse of available blocks and aggressive layout techniques. Also, thanks to the MOSFET subthreshold operation, the average power consumption is as low as 8μW/pixel.

  6. Extracellular Matrix Stiffness Regulates Osteogenic Differentiation through MAPK Activation

    PubMed Central

    Hwang, Jun-Ha; Byun, Mi Ran; Kim, A. Rum; Kim, Kyung Min; Cho, Hang Jun; Lee, Yo Han; Kim, Juwon; Jeong, Mi Gyeong; Hwang, Eun Sook; Hong, Jeong-Ho

    2015-01-01

    Mesenchymal stem cell (MSC) differentiation is regulated by the extracellular matrix (ECM) through activation of intracellular signaling mediators. The stiffness of the ECM was shown to be an important regulatory factor for MSC differentiation, and transcriptional coactivator with PDZ-binding motif (TAZ) was identified as an effector protein for MSC differentiation. However, the detailed underlying mechanism regarding the role of ECM stiffness and TAZ in MSC differentiation is not yet fully understood. In this report, we showed that ECM stiffness regulates MSC fate through ERK or JNK activation. Specifically, a stiff hydrogel matrix stimulates osteogenic differentiation concomitant with increased nuclear localization of TAZ, but inhibits adipogenic differentiation. ERK and JNK activity was significantly increased in cells cultured on a stiff hydrogel. TAZ activation was induced by ERK or JNK activation on a stiff hydrogel because exposure to an ERK or JNK inhibitor significantly decreased the nuclear localization of TAZ, indicating that ECM stiffness-induced ERK or JNK activation is important for TAZ-driven osteogenic differentiation. Taken together, these results suggest that ECM stiffness regulates MSC differentiation through ERK or JNK activation. PMID:26262877

  7. Extracellular Matrix Stiffness Regulates Osteogenic Differentiation through MAPK Activation.

    PubMed

    Hwang, Jun-Ha; Byun, Mi Ran; Kim, A Rum; Kim, Kyung Min; Cho, Hang Jun; Lee, Yo Han; Kim, Juwon; Jeong, Mi Gyeong; Hwang, Eun Sook; Hong, Jeong-Ho

    2015-01-01

    Mesenchymal stem cell (MSC) differentiation is regulated by the extracellular matrix (ECM) through activation of intracellular signaling mediators. The stiffness of the ECM was shown to be an important regulatory factor for MSC differentiation, and transcriptional coactivator with PDZ-binding motif (TAZ) was identified as an effector protein for MSC differentiation. However, the detailed underlying mechanism regarding the role of ECM stiffness and TAZ in MSC differentiation is not yet fully understood. In this report, we showed that ECM stiffness regulates MSC fate through ERK or JNK activation. Specifically, a stiff hydrogel matrix stimulates osteogenic differentiation concomitant with increased nuclear localization of TAZ, but inhibits adipogenic differentiation. ERK and JNK activity was significantly increased in cells cultured on a stiff hydrogel. TAZ activation was induced by ERK or JNK activation on a stiff hydrogel because exposure to an ERK or JNK inhibitor significantly decreased the nuclear localization of TAZ, indicating that ECM stiffness-induced ERK or JNK activation is important for TAZ-driven osteogenic differentiation. Taken together, these results suggest that ECM stiffness regulates MSC differentiation through ERK or JNK activation.

  8. High Matrix Metalloproteinase Activity is a Hallmark of Periapical Granulomas

    PubMed Central

    de Paula e Silva, Francisco Wanderley Garcia; D'Silva, Nisha J.; da Silva, Léa Assed Bezerra; Kapila, Yvonne Lorraine

    2009-01-01

    Introduction Inability to distinguish periapical cysts from granulomas prior to performing root canal treatment leads to uncertainty in treatment outcomes, because cysts have lower healing rates. Searching for differential expression of molecules within cysts or granulomas could provide information with regard to the identity of the lesion or suggest mechanistic differences that may form the basis for future therapeutic intervention. Thus, we investigated whether granulomas and cysts exhibit differential expression of extracellular matrix (ECM) molecules. Methods Human periapical granulomas, periapical cysts, and healthy periodontal ligament tissues were used to investigate the differential expression of ECM molecules by microarray analysis. Since matrix metalloproteinases (MMP) showed the highest differential expression in the microarray analysis, MMPs were further examined by in situ zymography and immunohistochemistry. Data were analyzed using one-way ANOVA followed by Tukey test. Results We observed that cysts and granulomas differentially expressed several ECM molecules, especially those from the matrix metalloproteinase (MMP) family. Compared to cysts, granulomas exhibited higher MMP enzymatic activity in areas stained for MMP-9. These areas were composed of polymorphonuclear cells (PMNs), in contrast to cysts. Similarly, MMP-13 was expressed by a greater number of cells in granulomas compared to cysts. Conclusion Our findings indicate that high enzymatic MMP activity in PMNs together with MMP-9 and MMP-13 stained cells could be a molecular signature of granulomas, unlike periapical cysts. PMID:19720222

  9. Electrochemical Proteolytic Beacon for Detection of Matrix Metalloproteinase Activities

    SciTech Connect

    Liu, Guodong; Wang, Jun; Wunschel, David S.; Lin, Yuehe

    2006-09-27

    This communication describes a novel method for detecting of matrix metalloproteinase-7 activity using a peptide substrate labeled with a ferrocene reporter. The substrate serves as a selective ‘electrochemical proteolytic beacon’ (EPB) for this metalloproteinase. The EPB is immobilized on a gold electrode surface to enable ‘on-off’ electrochemical signaling capability for uncleaved and cleaved events. The EPB is efficiently and selectively cleaved by MMP-7 as measured by the rate of decrease in redox current of ferrocene. Direct transduction of a signal corresponding to peptide cleavage events into an electronic signal thus provides a simple, sensitive route for detecting the MMP activity. The new method allows for identification of the activity of MMP-7 in concentrations as low as 3.4 pM. The concept can be extended to design multiple peptide substrate labeled with different electroactive reporters for assaying multiple MMPs activities.

  10. Electrochemical proteolytic beacon for detection of matrix metalloproteinase activities.

    PubMed

    Liu, Guodong; Wang, Jun; Wunschel, David S; Lin, Yuehe

    2006-09-27

    This communication describes a novel method for detecting matrix metalloproteinase-7 activity using a peptide substrate labeled with a ferrocene reporter. The substrate serves as a selective "electrochemical proteolytic beacon" (EPB) for this metalloproteinase. The EPB is immobilized on a gold electrode surface to enable "on-off" electrochemical signaling capability for uncleaved and cleaved events. The EPB is efficiently and selectively cleaved by MMP-7 as measured by the rate of decrease in redox current of ferrocene. Direct transduction of a signal corresponding to peptide cleavage events into an electronic signal thus provides a simple, sensitive route for detecting the MMP activity. The new method allows for identification of the activity of MMP-7 in concentrations as low as 3.4 pM. The concept can be extended to design a multiple peptide substrate labeled with different electroactive reporters for assaying multiple MMPs activities.

  11. CMOS digital pixel sensors: technology and applications

    NASA Astrophysics Data System (ADS)

    Skorka, Orit; Joseph, Dileepan

    2014-04-01

    CMOS active pixel sensor technology, which is widely used these days for digital imaging, is based on analog pixels. Transition to digital pixel sensors can boost signal-to-noise ratios and enhance image quality, but can increase pixel area to dimensions that are impractical for the high-volume market of consumer electronic devices. There are two main approaches to digital pixel design. The first uses digitization methods that largely rely on photodetector properties and so are unique to imaging. The second is based on adaptation of a classical analog-to-digital converter (ADC) for in-pixel data conversion. Imaging systems for medical, industrial, and security applications are emerging lower-volume markets that can benefit from these in-pixel ADCs. With these applications, larger pixels are typically acceptable, and imaging may be done in invisible spectral bands.

  12. Development of silicon micropattern pixel detectors

    NASA Astrophysics Data System (ADS)

    Heijne, E. H. M.; Antinori, F.; Beker, H.; Batignani, G.; Beusch, W.; Bonvicini, V.; Bosisio, L.; Boutonnet, C.; Burger, P.; Campbell, M.; Cantoni, P.; Catanesi, M. G.; Chesi, E.; Claeys, C.; Clemens, J. C.; Cohen Solal, M.; Darbo, G.; Da Via, C.; Debusschere, I.; Delpierre, P.; Di Bari, D.; Di Liberto, S.; Dierickx, B.; Enz, C. C.; Focardi, E.; Forti, F.; Gally, Y.; Glaser, M.; Gys, T.; Habrard, M. C.; Hallewell, G.; Hermans, L.; Heuser, J.; Hurst, R.; Inzani, P.; Jæger, J. J.; Jarron, P.; Karttaavi, T.; Kersten, S.; Krummenacher, F.; Leitner, R.; Lemeilleur, F.; Lenti, V.; Letheren, M.; Lokajicek, M.; Loukas, D.; Macdermott, M.; Maggi, G.; Manzari, V.; Martinengo, P.; Meddeler, G.; Meddi, F.; Mekkaoui, A.; Menetrey, A.; Middelkamp, P.; Morando, M.; Munns, A.; Musico, P.; Nava, P.; Navach, F.; Neyer, C.; Pellegrini, F.; Pengg, F.; Perego, R.; Pindo, M.; Pospisil, S.; Potheau, R.; Quercigh, E.; Redaelli, N.; Ridky, J.; Rossi, L.; Sauvage, D.; Segato, G.; Simone, S.; Sopko, B.; Stefanini, G.; Strakos, V.; Tempesta, P.; Tonelli, G.; Vegni, G.; Verweij, H.; Viertel, G. M.; Vrba, V.; Waisbard, J.; CERN RD19 Collaboration

    1994-09-01

    Successive versions of high speed, active silicon pixel detectors with integrated readout electronics have been developed for particle physics experiments using monolithic and hybrid technologies. Various matrices with binary output as well as a linear detector with analog output have been made. The hybrid binary matrix with 1024 cells (dimension 75 μm×500 μm) can capture events at ˜5 MHz and a selected event can then be read out in < 10 μs. In different beam tests at CERN a precision of 25 μm has been achieved and the efficiency was better than 99.2%. Detector thicknesses of 300 μm and 150 μm of silicon have been used. In a test with a 109Cd source a noise level of 170 e - r.m.s. (1.4 keV fwhm) has been measured with a threshold non-uniformity of 750 e - r.m.s. Objectives of the development work are the increase of the size of detecting area without loss of efficiency, the design of an appropriate readout architecture for collider operation, the reduction of material thickness in the detector, understanding of the threshold non-uniformity, study of the sensitivity of the pixel matrices to light and low energy electrons for scintillating fiber detector readout and last but not least, the optimization of cost and yield of the pixel detectors in production.

  13. The Belle II DEPFET pixel detector

    NASA Astrophysics Data System (ADS)

    Moser, Hans-Günther

    2016-09-01

    The Belle II experiment at KEK (Tsukuba, Japan) will explore heavy flavour physics (B, charm and tau) at the starting of 2018 with unprecedented precision. Charged particles are tracked by a two-layer DEPFET pixel device (PXD), a four-layer silicon strip detector (SVD) and the central drift chamber (CDC). The PXD will consist of two layers at radii of 14 mm and 22 mm with 8 and 12 ladders, respectively. The pixel sizes will vary, between 50 μm×(55-60) μm in the first layer and between 50 μm×(70-85) μm in the second layer, to optimize the charge sharing efficiency. These innermost layers have to cope with high background occupancy, high radiation and must have minimal material to reduce multiple scattering. These challenges are met using the DEPFET technology. Each pixel is a FET integrated on a fully depleted silicon bulk. The signal charge collected in the 'internal gate' modulates the FET current resulting in a first stage amplification and therefore very low noise. This allows very thin sensors (75 μm) reducing the overall material budget of the detector (0.21% X0). Four fold multiplexing of the column parallel readout allows read out a full frame of the pixel matrix in only 20 μs while keeping the power consumption low enough for air cooling. Only the active electronics outside the detector acceptance has to be cooled actively with a two phase CO2 system. Furthermore the DEPFET technology offers the unique feature of an electronic shutter which allows the detector to operate efficiently in the continuous injection mode of superKEKB.

  14. The ALICE Pixel Detector

    NASA Astrophysics Data System (ADS)

    Mercado-Perez, Jorge

    2002-07-01

    The present document is a brief summary of the performed activities during the 2001 Summer Student Programme at CERN under the Scientific Summer at Foreign Laboratories Program organized by the Particles and Fields Division of the Mexican Physical Society (Sociedad Mexicana de Fisica). In this case, the activities were related with the ALICE Pixel Group of the EP-AIT Division, under the supervision of Jeroen van Hunen, research fellow in this group. First, I give an introduction and overview to the ALICE experiment; followed by a description of wafer probing. A brief summary of the test beam that we had from July 13th to July 25th is given as well.

  15. Heterogeneity of serum activities of matrix metalloproteinases in chronic endometritis.

    PubMed

    Sukhikh, G T; Soboleva, G M; Silantyeva, E S; Shagerbieva, E A; Serov, V N

    2007-04-01

    Matrix metalloproteinases belong to the key molecules of tissue remodeling involved in physiological and pathological processes of the female reproductive system. Adequate levels of their expression in the endometrium are essential for effective implantation and uneventful pregnancy. Chronic inflammatory process in the endometrium is associated with low tissue expression of metalloproteinase-9. Histologically verified chronic endometritis is associated with low serum activities of metalloproteinases 2 and 9, which are restored after combined etiotropic therapy. We measured serum levels of metalloproteinases in patients with chronic endometritis concomitant with sterility and its changes during the first days after magnetotherapy. PMID:18214304

  16. Lumican: a new inhibitor of matrix metalloproteinase-14 activity.

    PubMed

    Pietraszek, Katarzyna; Chatron-Colliet, Aurore; Brézillon, Stéphane; Perreau, Corinne; Jakubiak-Augustyn, Anna; Krotkiewski, Hubert; Maquart, François-Xavier; Wegrowski, Yanusz

    2014-11-28

    We previously showed that lumican regulates MMP-14 expression. The aim of this study was to compare the effect of lumican and decorin on MMP-14 activity. In contrast to decorin, the glycosylated form of lumican was able to significantly decrease MMP-14 activity in B16F1 melanoma cells. Our results suggest that a direct interaction occurs between lumican and MMP-14. Lumican behaves as a competitive inhibitor which leads to a complete blocking of the activity of MMP-14. It binds to the catalytic domain of MMP-14 with moderate affinity (KD∼275 nM). Lumican may protect collagen against MMP-14 proteolysis, thus influencing cell-matrix interaction in tumor progression. PMID:25304424

  17. Analysis and Enhancement of Low-Light-Level Performance of Photodiode-Type CMOS Active Pixel Images Operated with Sub-Threshold Reset

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata; Yang, Guang; Ortiz, Monico; Wrigley, Christopher; Hancock, Bruce; Cunningham, Thomas

    2000-01-01

    Noise in photodiode-type CMOS active pixel sensors (APS) is primarily due to the reset (kTC) noise at the sense node, since it is difficult to implement in-pixel correlated double sampling for a 2-D array. Signal integrated on the photodiode sense node (SENSE) is calculated by measuring difference between the voltage on the column bus (COL) - before and after the reset (RST) is pulsed. Lower than kTC noise can be achieved with photodiode-type pixels by employing "softreset" technique. Soft-reset refers to resetting with both drain and gate of the n-channel reset transistor kept at the same potential, causing the sense node to be reset using sub-threshold MOSFET current. However, lowering of noise is achieved only at the expense higher image lag and low-light-level non-linearity. In this paper, we present an analysis to explain the noise behavior, show evidence of degraded performance under low-light levels, and describe new pixels that eliminate non-linearity and lag without compromising noise.

  18. Modeling mechanophore activation within a crosslinked glassy matrix

    NASA Astrophysics Data System (ADS)

    Silberstein, Meredith N.; Min, Kyoungmin; Cremar, Lee D.; Degen, Cassandra M.; Martinez, Todd J.; Aluru, Narayana R.; White, Scott R.; Sottos, Nancy R.

    2013-07-01

    Mechanically induced reactivity is a promising means for designing self-reporting materials. Mechanically sensitive chemical groups called mechanophores are covalently linked into polymers in order to trigger specific chemical reactions upon mechanical loading. These mechanophores can be linked either within the backbone or as crosslinks between backbone segments. Mechanophore response is sensitive to both the matrix properties and placement within the matrix, providing two avenues for material design. A model framework is developed to describe reactivity of mechanophores located as crosslinks in a glassy polymer matrix. Simulations are conducted at the molecular and macromolecular scales in order to develop macroscale constitutive relations. The model is developed specifically for the case of spiropyran (SP) in lightly crosslinked polymethylmethacrylate (PMMA). This optically trackable mechanophore (fluorescent when activated) allows the model to be assessed in terms of observed experimental behavior. The force modified potential energy surface (FMPES) framework is used in conjunction with ab initio steered molecular dynamics (MD) simulations of SP to determine the mechanophore kinetics. MD simulations of the crosslinked PMMA structure under shear deformation are used to determine the relationship between macroscale stress and local force on the crosslinks. A continuum model implemented in a finite element framework synthesizes these mechanochemical relations with the mechanical behavior. The continuum model with parameters taken directly from the FMPES and MD analyses under predicts stress-driven activation relative to experimental data. The continuum model, with the physically motivated modification of force fluctuations, provides an accurate prediction for monotonic loading across three decades of strain rate and creep loading, suggesting that the fundamental physics are captured.

  19. Matrix metalloproteinase-1 inhibitory activity of Kaempferia pandurata Roxb.

    PubMed

    Shim, Jae-Seok; Choi, Eun-Jung; Lee, Chan-Woo; Kim, Han-Sung; Hwang, Jae-Kwan

    2009-06-01

    Matrix metalloproteinase (MMP)-1 is a superfamily of zinc-dependent endopeptidases that are capable of degrading all components of the extracellular matrix. Kaempferia pandurata extract (0.01-0.5 microg/mL) significantly reduced the expression of MMP-1 and induced the expression of type 1 procollagen at the protein and mRNA levels in a dose-dependent manner. Ultraviolet (UV)-induced MMP-1 initiates cleavage of fibrillar collagen. Once cleaved by MMP-1, collagen can be further degraded by elevated levels of MMP-3 and MMP-9. It was found that increased MMP-1 expression due to UV irradiation was mediated by activation of mitogen-activated protein kinases such as extracellular-regulated kinase (ERK), Jun N-terminal kinase (JNK), and p38 kinase. Treatment of K. pandurata extract in the range of 0.01-0.5 microg/mL inhibited the UV-induced phosphorylations of ERK, JNK, and p38, respectively. Moreover, inhibition of phosphorylated ERK, JNK, and p38 by K. pandurata extract resulted in decreased c-Fos expression and c-Jun phosphorylation induced by UV light. The results strongly suggest that K. pandurata is potentially useful for the prevention and treatment of skin aging.

  20. Organic thin-film transistor arrays for active-matrix organic light emitting diode

    NASA Astrophysics Data System (ADS)

    Lee, Sangyun; Moon, Hyunsik; Kim, Do H.; Koo, Bon-Won; Jeong, Eun-Jeong; Lee, Bang-Lin; Kim, Joo-Young; Lee, Eunkyung; Hahn, Kook-Min; Han, Jeong-Seok; Park, Jung-Il; Seon, Jong-Baek; Kim, Jung-Woo; Chun, Young-Tea; Kim, Sangyeol; Kang, Sung K.

    2007-09-01

    We developed an active matrix organic light-emitting diodes (AMOLEDs) on a glass using two organic thin-film transistors (OTFTs) and a capacitor in a pixel. OTFTs switching-arrays with 64 scan lines and 64 (RGB) data lines were designed and fabricated to drive OLED arrays. In this study, OTFT devices have bottom contact structures with an ink-jet printed polymer semiconductor and an organic insulator as a gate dielectric. The width and length of the switching OTFT is 500μm and 10μm, respectively and the driving OTFT has 900μm channel width with the same channel length. The characteristics of the OTFTs were examined using test cells around display area. On/off ratio, mobility, on-current of switching OTFT and on-current of driving OTFT were 10 6, 0.1 cm2/V-sec, order of 8μA and over 70 μA respectively. These properties were enough to drive the AMOLEDs over 60 Hz frame rate. AMOLEDs composed of the OTFT switching arrays and OLEDs made by deposition of small molecule materials were fabricated and driven to make moving images, successfully.

  1. Separated Carbon Nanotube Macroelectronics for Active Matrix Organic Light-Emitting Diode Displays

    NASA Astrophysics Data System (ADS)

    Fu, Yue; Zhang, Jialu; Wang, Chuan; Chen, Pochiang; Zhou, Chongwu

    2012-02-01

    Active matrix organic light-emitting diode (AMOLED) display holds great potential for the next generation visual technologies due to its high light efficiency, flexibility, lightweight, and low-temperature processing. However, suitable thin-film transistors (TFTs) are required to realize the advantages of AMOLED. Pre-separated, semiconducting enriched carbon nanotubes are excellent candidates for this purpose because of their excellent mobility, high percentage of semiconducting nanotubes, and room-temperature processing compatibility. Here we report, for the first time, the demonstration of AMOLED displays driven by separated nanotube thin-film transistors (SN-TFTs) including key technology components such as large-scale high-yield fabrication of devices with superior performance, carbon nanotube film density optimization, bilayer gate dielectric for improved substrate adhesion to the deposited nanotube film, and the demonstration of monolithically integrated AMOLED display elements with 500 pixels driven by 1000 SN-TFTs. Our approach can serve as the critical foundation for future nanotube-based thin-film display electronics.

  2. Plastic substrates for active matrix liquid crystal display incapable of withstanding processing temperature of over 200 C and method of fabrication

    DOEpatents

    Carey, P.G.; Smith, P.M.; Havens, J.H.; Jones, P.

    1999-01-05

    Bright-polarizer-free, active-matrix liquid crystal displays (AMLCDs) are formed on plastic substrates. The primary components of the display are a pixel circuit fabricated on one plastic substrate, an intervening liquid-crystal material, and a counter electrode on a second plastic substrate. The-pixel circuit contains one or more thin-film transistors (TFTs) and either a transparent or reflective pixel electrode manufactured at sufficiently low temperatures to avoid damage to the plastic substrate. Fabrication of the TFTs can be carried out at temperatures less than 100 C. The liquid crystal material is a commercially made nematic curvilinear aligned phase (NCAP) film. The counter electrode is comprised of a plastic substrate coated with a transparent conductor, such as indium-doped tin oxide (ITO). By coupling the active matrix with NCAP, a high-information content can be provided in a bright, fully plastic package. Applications include any low cost portable electronics containing flat displays where ruggedization of the display is desired. 12 figs.

  3. Plastic substrates for active matrix liquid crystal display incapable of withstanding processing temperature of over 200.degree. C and method of fabrication

    DOEpatents

    Carey, Paul G.; Smith, Patrick M.; Havens, John; Jones, Phil

    1999-01-01

    Bright-polarizer-free, active-matrix liquid crystal displays (AMLCDs) are formed on plastic substrates. The primary components of the display are a pixel circuit fabricated on one plastic substrate, an intervening liquid-crystal material, and a counter electrode on a second plastic substrate. The-pixel circuit contains one or more thin-film transistors (TFTs) and either a transparent or reflective pixel electrode manufactured at sufficiently low temperatures to avoid damage to the plastic substrate. Fabrication of the TFTs can be carried out at temperatures less than 100.degree. C. The liquid crystal material is a commercially made nematic curvilinear aligned phase (NCAP) film. The counter electrode is comprised of a plastic substrate coated with a transparent conductor, such as indium-doped tin oxide (ITO). By coupling the active matrix with NCAP, a high-information content can be provided in a bright, fully plastic package. Applications include any low cost portable electronics containing flat displays where ruggedization of the display is desired.

  4. Residual matrix from different separation techniques impacts exosome biological activity

    PubMed Central

    Paolini, Lucia; Zendrini, Andrea; Noto, Giuseppe Di; Busatto, Sara; Lottini, Elisabetta; Radeghieri, Annalisa; Dossi, Alessandra; Caneschi, Andrea; Ricotta, Doris; Bergese, Paolo

    2016-01-01

    Exosomes are gaining a prominent role in research due to their intriguing biology and several therapeutic opportunities. However, their accurate purification from body fluids and detailed physicochemical characterization remain open issues. We isolated exosomes from serum of patients with Multiple Myeloma by four of the most popular purification methods and assessed the presence of residual contaminants in the preparations through an ad hoc combination of biochemical and biophysical techniques - including Western Blot, colloidal nanoplasmonics, atomic force microscopy (AFM) and scanning helium ion microscopy (HIM). The preparations obtained by iodixanol and sucrose gradients were highly pure. To the contrary, those achieved with limited processing (serial centrifugation or one step precipitation kit) resulted contaminated by a residual matrix, embedding the exosomes. The contaminated preparations showed lower ability to induce NfkB nuclear translocation in endothelial cells with respect to the pure ones, probably because the matrix prevents the interaction and fusion of the exosomes with the cell membrane. These findings suggest that exosome preparation purity must be carefully assessed since it may interfere with exosome biological activity. Contaminants can be reliably probed only by an integrated characterization approach aimed at both the molecular and the colloidal length scales. PMID:27009329

  5. Embedded Touch Sensing Circuit Using Mutual Capacitance for Active-Matrix Organic Light-Emitting Diode Display

    NASA Astrophysics Data System (ADS)

    Park, Young-Ju; Seok, Su-Jeong; Park, Sang-Ho; Kim, Ohyun

    2011-03-01

    We propose and simulate an embedded touch sensing circuit for active-matrix organic light-emitting diode (AMOLED) displays. The circuit consists of three thin-film transistors (TFTs), one fixed capacitor, and one variable capacitor. AMOLED displays do not have a variable capacitance characteristic, so we realized a variable capacitor to detect touches in the sensing pixel by exploiting the change in the mutual capacitance between two electrodes that is caused by touch. When a dielectric substance approaches two electrodes, the electric field is shunted so that the mutual capacitance decreases. We use the existing TFT process to form the variable capacitor, so no additional process is needed. We use advanced solid-phase-crystallization TFTs because of their stability and uniformity. The proposed circuit detects multi-touch points by a scanning process.

  6. Noise Characterization of Polycrystalline Silicon Thin Film Transistors for X-ray Imagers Based on Active Pixel Architectures.

    PubMed

    Antonuk, L E; Koniczek, M; McDonald, J; El-Mohri, Y; Zhao, Q; Behravan, M

    2008-01-01

    An examination of the noise of polycrystalline silicon thin film transistors, in the context of flat panel x-ray imager development, is reported. The study was conducted in the spirit of exploring how the 1/f, shot and thermal noise components of poly-Si TFTs, determined from current noise power spectral density measurements, as well as through calculation, can be used to assist in the development of imagers incorporating pixel amplification circuits based on such transistors. PMID:20862269

  7. Driving Method Compensating for the Hysteresis of Polycrystalline Silicon Thin-Film Transistors for Active-Matrix Organic Light-Emitting Diode Displays

    NASA Astrophysics Data System (ADS)

    Jung, Myoung-Hoon; Kim, Ohyun; Kim, Byeong-Koo; Chung, Hoon-Ju

    2009-05-01

    A new driving method for active-matrix organic light-emitting diode displays is proposed and evaluated. The pixel structure of the proposed driving method is composed of three thin-film transistors (TFTs) and one capacitor. It inserts black data into display images to reset driving TFTs for the purpose of maintaining constant electrical characteristics of driving TFTs. The proposed driving scheme is less sensitive to the hysteresis of low-temperature polycrystalline silicon (LTPS) TFTs than the conventional pixel structure with two TFTs and one capacitor, and this scheme can virtually eliminate the recoverable residual image that occurs owing to the hysteresis characteristics of LTPS TFTs. In the proposed driving scheme, black data are inserted into displayed images so that the motion image quality is improved.

  8. New Driving Scheme to Improve Hysteresis Characteristics of Organic Thin Film Transistor-Driven Active-Matrix Organic Light Emitting Diode Display

    NASA Astrophysics Data System (ADS)

    Yamamoto, Toshihiro; Nakajima, Yoshiki; Takei, Tatsuya; Fujisaki, Yoshihide; Fukagawa, Hirohiko; Suzuki, Mitsunori; Motomura, Genichi; Sato, Hiroto; Tokito, Shizuo; Fujikake, Hideo

    2011-02-01

    A new driving scheme for an active-matrix organic light emitting diode (AMOLED) display was developed to prevent the picture quality degradation caused by the hysteresis characteristics of organic thin film transistors (OTFTs). In this driving scheme, the gate electrode voltage of a driving-OTFT is directly controlled through the storage capacitor so that the operating point for the driving-OTFT is on the same hysteresis curve for every pixel after signal data are stored in the storage capacitor. Although the number of OTFTs in each pixel for the AMOLED display is restricted because OTFT size should be large enough to drive organic light emitting diodes (OLEDs) due to their small carrier mobility, it can improve the picture quality for an OTFT-driven flexible OLED display with the basic two transistor-one capacitor circuitry.

  9. A flexible organic active matrix circuit fabricated using novel organic thin film transistors and organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Heredia, G.; González, L. A.; Alshareef, H. N.; Gnade, B. E.; Quevedo-López, M.

    2010-11-01

    We present an active matrix circuit fabricated on plastic (polyethylene naphthalene, PEN) and glass substrates using organic thin film transistors and organic capacitors to control organic light-emitting diodes (OLEDs). The basic circuit is fabricated using two pentacene-based transistors and a capacitor using a novel aluminum oxide/parylene stack (Al2O3/parylene) as the dielectric for both the transistor and the capacitor. We report that our circuit can deliver up to 15 µA to each OLED pixel. To achieve 200 cd m-2 of brightness a 10 µA current is needed; therefore, our approach can initially deliver 1.5× the required current to drive a single pixel. In contrast to parylene-only devices, the Al2O3/parylene stack does not fail after stressing at a field of 1.7 MV cm-1 for >10 000 s, whereas 'parylene only' devices show breakdown at approximately 1000 s. Details of the integration scheme are presented.

  10. Calcium-Oxidant Signaling Network Regulates AMP-activated Protein Kinase (AMPK) Activation upon Matrix Deprivation*

    PubMed Central

    Sundararaman, Ananthalakshmy; Amirtham, Usha; Rangarajan, Annapoorni

    2016-01-01

    The AMP-activated protein kinase (AMPK) has recently been implicated in anoikis resistance. However, the molecular mechanisms that activate AMPK upon matrix detachment remain unexplored. In this study, we show that AMPK activation is a rapid and sustained phenomenon upon matrix deprivation, whereas re-attachment to the matrix leads to its dephosphorylation and inactivation. Because matrix detachment leads to loss of integrin signaling, we investigated whether integrin signaling negatively regulates AMPK activation. However, modulation of focal adhesion kinase or Src, the major downstream components of integrin signaling, failed to cause a corresponding change in AMPK signaling. Further investigations revealed that the upstream AMPK kinases liver kinase B1 (LKB1) and Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ) contribute to AMPK activation upon detachment. In LKB1-deficient cells, we found AMPK activation to be predominantly dependent on CaMKKβ. We observed no change in ATP levels under detached conditions at early time points suggesting that rapid AMPK activation upon detachment was not triggered by energy stress. We demonstrate that matrix deprivation leads to a spike in intracellular calcium as well as oxidant signaling, and both these intracellular messengers contribute to rapid AMPK activation upon detachment. We further show that endoplasmic reticulum calcium release-induced store-operated calcium entry contributes to intracellular calcium increase, leading to reactive oxygen species production, and AMPK activation. We additionally show that the LKB1/CaMKK-AMPK axis and intracellular calcium levels play a critical role in anchorage-independent cancer sphere formation. Thus, the Ca2+/reactive oxygen species-triggered LKB1/CaMKK-AMPK signaling cascade may provide a quick, adaptable switch to promote survival of metastasizing cancer cells. PMID:27226623

  11. Amorphous In–Ga–Zn–O thin-film transistor active pixel sensor x-ray imager for digital breast tomosynthesis

    SciTech Connect

    Zhao, Chumin; Kanicki, Jerzy

    2014-09-15

    Purpose: The breast cancer detection rate for digital breast tomosynthesis (DBT) is limited by the x-ray image quality. The limiting Nyquist frequency for current DBT systems is around 5 lp/mm, while the fine image details contained in the high spatial frequency region (>5 lp/mm) are lost. Also today the tomosynthesis patient dose is high (0.67–3.52 mGy). To address current issues, in this paper, for the first time, a high-resolution low-dose organic photodetector/amorphous In–Ga–Zn–O thin-film transistor (a-IGZO TFT) active pixel sensor (APS) x-ray imager is proposed for next generation DBT systems. Methods: The indirect x-ray detector is based on a combination of a novel low-cost organic photodiode (OPD) and a cesium iodide-based (CsI:Tl) scintillator. The proposed APS x-ray imager overcomes the difficulty of weak signal detection, when small pixel size and low exposure conditions are used, by an on-pixel signal amplification with a significant charge gain. The electrical performance of a-IGZO TFT APS pixel circuit is investigated by SPICE simulation using modified Rensselaer Polytechnic Institute amorphous silicon (a-Si:H) TFT model. Finally, the noise, detective quantum efficiency (DQE), and resolvability of the complete system are modeled using the cascaded system formalism. Results: The result demonstrates that a large charge gain of 31–122 is achieved for the proposed high-mobility (5–20 cm{sup 2}/V s) amorphous metal-oxide TFT APS. The charge gain is sufficient to eliminate the TFT thermal noise, flicker noise as well as the external readout circuit noise. Moreover, the low TFT (<10{sup −13} A) and OPD (<10{sup −8} A/cm{sup 2}) leakage currents can further reduce the APS noise. Cascaded system analysis shows that the proposed APS imager with a 75 μm pixel pitch can effectively resolve the Nyquist frequency of 6.67 lp/mm, which can be further improved to ∼10 lp/mm if the pixel pitch is reduced to 50 μm. Moreover, the

  12. Collagenolytic Matrix Metalloproteinase Activities toward Peptomeric Triple-Helical Substrates.

    PubMed

    Stawikowski, Maciej J; Stawikowska, Roma; Fields, Gregg B

    2015-05-19

    Although collagenolytic matrix metalloproteinases (MMPs) possess common domain organizations, there are subtle differences in their processing of collagenous triple-helical substrates. In this study, we have incorporated peptoid residues into collagen model triple-helical peptides and examined MMP activities toward these peptomeric chimeras. Several different peptoid residues were incorporated into triple-helical substrates at subsites P3, P1, P1', and P10' individually or in combination, and the effects of the peptoid residues were evaluated on the activities of full-length MMP-1, MMP-8, MMP-13, and MMP-14/MT1-MMP. Most peptomers showed little discrimination between MMPs. However, a peptomer containing N-methyl Gly (sarcosine) in the P1' subsite and N-isobutyl Gly (NLeu) in the P10' subsite was hydrolyzed efficiently only by MMP-13 [nomenclature relative to the α1(I)772-786 sequence]. Cleavage site analysis showed hydrolysis at the Gly-Gln bond, indicating a shifted binding of the triple helix compared to the parent sequence. Favorable hydrolysis by MMP-13 was not due to sequence specificity or instability of the substrate triple helix but rather was based on the specific interactions of the P7' peptoid residue with the MMP-13 hemopexin-like domain. A fluorescence resonance energy transfer triple-helical peptomer was constructed and found to be readily processed by MMP-13, not cleaved by MMP-1 and MMP-8, and weakly hydrolyzed by MT1-MMP. The influence of the triple-helical structure containing peptoid residues on the interaction between MMP subsites and individual substrate residues may provide additional information about the mechanism of collagenolysis, the understanding of collagen specificity, and the design of selective MMP probes.

  13. Performance of a direct-detection active matrix flat panel dosimeter (AMFPD) for IMRT measurements

    SciTech Connect

    Chen Yu; Moran, Jean M.; Roberts, Donald A.; El-Mohri, Youcef; Antonuk, Larry E.; Fraass, Benedick A.

    2007-12-15

    The dosimetric performance of a direct-detection active matrix flat panel dosimeter (AMFPD) is reported for intensity modulated radiation therapy (IMRT) measurements. The AMFPD consists of a-Si:H photodiodes and thin-film transistors deposited on a glass substrate with no overlying scintillator screen or metal plate. The device is operated at 0.8 frames per second in a continuous acquisition or fluoroscopic mode. The effect of the applied bias voltage across the photodiodes on the response of the AMFPD was evaluated because this parameter affects dark signal, lag contributions, and pixel sensitivity. In addition, the AMPFD response was evaluated as a function of dose, dose rate, and energy, for static fields at 10 cm depth. In continuous acquisition mode, the AMFPD maintained a linear dose response (r{sup 2}>0.99999) up to at least 1040 cGy. In order to obtain reliable integrated dose results for IMRT fields, the effects of lag on the radiation signal were minimized by operating the system at the highest frame rate and at an appropriate reverse bias voltage. Segmental MLC and dynamic MLC IMRT fields were measured with the AMFPD, and the results were compared to film, using standard methods for reliable film dosimetry. Both AMFPD and film measurements were independently converted to dose in cGy. {gamma} and {chi} values were calculated as indices of agreement. The results from the AMFPD were in excellent agreement with those from film. When 2% of D{sub max} and 2 mm of distance to agreement were used as the criteria, 98% of the region of interest (defined as the region where dose is greater than 5% of D{sub max}) satisfied |{chi}|{<=}1 on average across the cases that were tested.

  14. PixelLearn

    NASA Technical Reports Server (NTRS)

    Mazzoni, Dominic; Wagstaff, Kiri; Bornstein, Benjamin; Tang, Nghia; Roden, Joseph

    2006-01-01

    PixelLearn is an integrated user-interface computer program for classifying pixels in scientific images. Heretofore, training a machine-learning algorithm to classify pixels in images has been tedious and difficult. PixelLearn provides a graphical user interface that makes it faster and more intuitive, leading to more interactive exploration of image data sets. PixelLearn also provides image-enhancement controls to make it easier to see subtle details in images. PixelLearn opens images or sets of images in a variety of common scientific file formats and enables the user to interact with several supervised or unsupervised machine-learning pixel-classifying algorithms while the user continues to browse through the images. The machinelearning algorithms in PixelLearn use advanced clustering and classification methods that enable accuracy much higher than is achievable by most other software previously available for this purpose. PixelLearn is written in portable C++ and runs natively on computers running Linux, Windows, or Mac OS X.

  15. Pixelated filters for spatial imaging

    NASA Astrophysics Data System (ADS)

    Mathieu, Karine; Lequime, Michel; Lumeau, Julien; Abel-Tiberini, Laetitia; Savin De Larclause, Isabelle; Berthon, Jacques

    2015-10-01

    Small satellites are often used by spatial agencies to meet scientific spatial mission requirements. Their payloads are composed of various instruments collecting an increasing amount of data, as well as respecting the growing constraints relative to volume and mass; So small-sized integrated camera have taken a favored place among these instruments. To ensure scene specific color information sensing, pixelated filters seem to be more attractive than filter wheels. The work presented here, in collaboration with Institut Fresnel, deals with the manufacturing of this kind of component, based on thin film technologies and photolithography processes. CCD detectors with a pixel pitch about 30 μm were considered. In the configuration where the matrix filters are positioned the closest to the detector, the matrix filters are composed of 2x2 macro pixels (e.g. 4 filters). These 4 filters have a bandwidth about 40 nm and are respectively centered at 550, 700, 770 and 840 nm with a specific rejection rate defined on the visible spectral range [500 - 900 nm]. After an intense design step, 4 thin-film structures have been elaborated with a maximum thickness of 5 μm. A run of tests has allowed us to choose the optimal micro-structuration parameters. The 100x100 matrix filters prototypes have been successfully manufactured with lift-off and ion assisted deposition processes. High spatial and spectral characterization, with a dedicated metrology bench, showed that initial specifications and simulations were globally met. These excellent performances knock down the technological barriers for high-end integrated specific multi spectral imaging.

  16. Active matrix metalloproteinase-7 is associated with invasion in buccal squamous cell carcinoma.

    PubMed

    Chuang, Hui-Ching; Su, Chih-Ying; Huang, Hsuang-Ying; Huang, Chao-Cheng; Chien, Chih-Yen; Du, Yung-Ying; Chuang, Jiin-Haur

    2008-12-01

    Protein microarrays have shown that matrix metalloproteinase-7 is upregulated in head and neck squamous cell carcinomas, but its role in local tissue invasion is still uncertain. We investigated the expression of active matrix metalloproteinase-7, using tissue microarray, immunohistochemistry, and western blotting, in oral tissues from 24 patients with buccal squamous cell carcinoma, and correlated the findings with clinicopathological features. Normal buccal tissue samples from the same patients, obtained at sites at least 1 cm from tumor tissue, served as normal controls. Total matrix metalloproteinase-7 was detected on western blots in 9 of 15 (60%) tumor tissue samples and in 2 of 15 (13%) normal mucosal samples; this difference was significant (P=0.008). Moreover, the active matrix metalloproteinase-7 was expressed only in eight of the nine (89%) tumor samples that expressed matrix metalloproteinase-7, and in none of the normal tissue samples, regardless of the expression status of the pro-matrix metalloproteinase-7. Immunostaining of matrix metalloproteinase-7 was observed histologically in both tumor and nonneoplastic epithelium, but immunostaining of active matrix metalloproteinase-7 was present only in tumor nests. Expression of active matrix metalloproteinase-7 was associated with larger tumor size (P=0.022) and was significantly higher in buccal squamous cell carcinoma with adjacent skin or bone invasion (P=0.036). In conclusion, active matrix metalloproteinase-7 expression was associated with more aggressive buccal squamous cell carcinomas. PMID:18931651

  17. Automatic repair in active-matrix liquid crystal display (AMLCD)

    NASA Astrophysics Data System (ADS)

    Qiu, Hongjie; Sheng, King C.; Lam, Joseph K.; Knuth, Tim; Miller, Mike; Addiego, Ginetto

    1994-04-01

    This paper presents an automatic AMLCD repair system utilizing real-time video, image processing and analysis, pattern recognition, and artificial intelligence. The system fundamentally includes automatic optical focus, automatic alignment, defect detection, defect analysis and identification, repair point and path definition, and automatic metal removal and addition (cutting, ablating, and metal deposition). Automatic alignment includes mark alignment as well AMLCD pixel alignment. The features (area, centroid, slope, perimeter, length, width and relative location between objects of interest) are measured for defect analysis. A least cost criterion is employed for defect detection and classification. The choice of repair process is determined by two defect types, either `Open' or `Short'. The repair point and path definition is made from the material structure type such as Data line, Gate line, and ITO area, defect position, and repair rules. The rules are generated from the global and local knowledge. In the automatic repair process, the system automatically performs optical focus, mark and pixel alignment, defect detection and classification, and laser writing or cutting.

  18. Sub-pixel mapping of water boundaries using pixel swapping algorithm (case study: Tagliamento River, Italy)

    NASA Astrophysics Data System (ADS)

    Niroumand-Jadidi, Milad; Vitti, Alfonso

    2015-10-01

    Taking the advantages of remotely sensed data for mapping and monitoring of water boundaries is of particular importance in many different management and conservation activities. Imagery data are classified using automatic techniques to produce maps entering the water bodies' analysis chain in several and different points. Very commonly, medium or coarse spatial resolution imagery is used in studies of large water bodies. Data of this kind is affected by the presence of mixed pixels leading to very outstanding problems, in particular when dealing with boundary pixels. A considerable amount of uncertainty inescapably occurs when conventional hard classifiers (e.g., maximum likelihood) are applied on mixed pixels. In this study, Linear Spectral Mixture Model (LSMM) is used to estimate the proportion of water in boundary pixels. Firstly by applying an unsupervised clustering, the water body is identified approximately and a buffer area considered ensuring the selection of entire boundary pixels. Then LSMM is applied on this buffer region to estimate the fractional maps. However, resultant output of LSMM does not provide a sub-pixel map corresponding to water abundances. To tackle with this problem, Pixel Swapping (PS) algorithm is used to allocate sub-pixels within mixed pixels in such a way to maximize the spatial proximity of sub-pixels and pixels in the neighborhood. The water area of two segments of Tagliamento River (Italy) are mapped in sub-pixel resolution (10m) using a 30m Landsat image. To evaluate the proficiency of the proposed approach for sub-pixel boundary mapping, the image is also classified using a conventional hard classifier. A high resolution image of the same area is also classified and used as a reference for accuracy assessment. According to the results, sub-pixel map shows in average about 8 percent higher overall accuracy than hard classification and fits very well in the boundaries with the reference map.

  19. Active Matrix Organic Light Emitting Diode (AMOLED) Environmental Test Report

    NASA Technical Reports Server (NTRS)

    Salazar, George A.

    2013-01-01

    This report focuses on the limited environmental testing of the AMOLED display performed as an engineering evaluation by The NASA Johnson Space Center (JSC)-specifically. EMI. Thermal Vac, and radiation tests. The AMOLED display is an active-matrix Organic Light Emitting Diode (OLED) technology. The testing provided an initial understanding of the technology and its suitability for space applications. Relative to light emitting diode (LED) displays or liquid crystal displays (LCDs), AMOLED displays provide a superior viewing experience even though they are much lighter and smaller, produce higher contrast ratio and richer colors, and require less power to operate than LCDs. However, AMOLED technology has not been demonstrated in a space environment. Therefore, some risks with the technology must be addressed before they can be seriously considered for human spaceflight. The environmental tests provided preliminary performance data on the ability of the display technology to handle some of the simulated induced space/spacecraft environments that an AMOLED display will see during a spacecraft certification test program. This engineering evaluation is part of a Space Act Agreement (SM) between The NASA/JSC and Honeywell International (HI) as a collaborative effort to evaluate the potential use of AMOLED technology for future human spaceflight missions- both government-led and commercial. Under this SM, HI is responsible for doing optical performance evaluation, as well as temperature and touch screen studies. The NASA/JSC is responsible for performing environmental testing comprised of EMI, Thermal Vac, and radiation tests. Additionally, as part of the testing, limited optical data was acquired to assess performance as the display was subjected to the induced environments. The NASA will benefit from this engineering evaluation by understanding AMOLED suitability for future use in space as well as becoming a smarter buyer (or developer) of the technology. HI benefits

  20. High density pixel array

    NASA Technical Reports Server (NTRS)

    Wiener-Avnear, Eliezer (Inventor); McFall, James Earl (Inventor)

    2004-01-01

    A pixel array device is fabricated by a laser micro-milling method under strict process control conditions. The device has an array of pixels bonded together with an adhesive filling the grooves between adjacent pixels. The array is fabricated by moving a substrate relative to a laser beam of predetermined intensity at a controlled, constant velocity along a predetermined path defining a set of grooves between adjacent pixels so that a predetermined laser flux per unit area is applied to the material, and repeating the movement for a plurality of passes of the laser beam until the grooves are ablated to a desired depth. The substrate is of an ultrasonic transducer material in one example for fabrication of a 2D ultrasonic phase array transducer. A substrate of phosphor material is used to fabricate an X-ray focal plane array detector.

  1. Matrix viscoplasticity and its shielding by active mechanics in microtissue models: experiments and mathematical modeling

    NASA Astrophysics Data System (ADS)

    Liu, Alan S.; Wang, Hailong; Copeland, Craig R.; Chen, Christopher S.; Shenoy, Vivek B.; Reich, Daniel H.

    2016-09-01

    The biomechanical behavior of tissues under mechanical stimulation is critically important to physiological function. We report a combined experimental and modeling study of bioengineered 3D smooth muscle microtissues that reveals a previously unappreciated interaction between active cell mechanics and the viscoplastic properties of the extracellular matrix. The microtissues’ response to stretch/unstretch actuations, as probed by microcantilever force sensors, was dominated by cellular actomyosin dynamics. However, cell lysis revealed a viscoplastic response of the underlying model collagen/fibrin matrix. A model coupling Hill-type actomyosin dynamics with a plastic perfectly viscoplastic description of the matrix quantitatively accounts for the microtissue dynamics, including notably the cells’ shielding of the matrix plasticity. Stretch measurements of single cells confirmed the active cell dynamics, and were well described by a single-cell version of our model. These results reveal the need for new focus on matrix plasticity and its interactions with active cell mechanics in describing tissue dynamics.

  2. Matrix viscoplasticity and its shielding by active mechanics in microtissue models: experiments and mathematical modeling

    PubMed Central

    Liu, Alan S.; Wang, Hailong; Copeland, Craig R.; Chen, Christopher S.; Shenoy, Vivek B.; Reich, Daniel H.

    2016-01-01

    The biomechanical behavior of tissues under mechanical stimulation is critically important to physiological function. We report a combined experimental and modeling study of bioengineered 3D smooth muscle microtissues that reveals a previously unappreciated interaction between active cell mechanics and the viscoplastic properties of the extracellular matrix. The microtissues’ response to stretch/unstretch actuations, as probed by microcantilever force sensors, was dominated by cellular actomyosin dynamics. However, cell lysis revealed a viscoplastic response of the underlying model collagen/fibrin matrix. A model coupling Hill-type actomyosin dynamics with a plastic perfectly viscoplastic description of the matrix quantitatively accounts for the microtissue dynamics, including notably the cells’ shielding of the matrix plasticity. Stretch measurements of single cells confirmed the active cell dynamics, and were well described by a single-cell version of our model. These results reveal the need for new focus on matrix plasticity and its interactions with active cell mechanics in describing tissue dynamics. PMID:27671239

  3. Performance of capacitively coupled active pixel sensors in 180 nm HV-CMOS technology after irradiation to HL-LHC fluences

    NASA Astrophysics Data System (ADS)

    Feigl, S.

    2014-03-01

    In this ATLAS upgrade R&D project, we explore the concept of using a deep-submicron HV-CMOS process to produce a drop-in replacement for traditional radiation-hard silicon sensors. Such active sensors contain simple circuits, e.g. amplifiers and discriminators, but still require a traditional (pixel or strip) readout chip. This approach yields most advantages of MAPS (improved resolution, reduced cost and material budget, etc.), without the complication of full integration on a single chip. After outlining the basic design of the HV2FEI4 test ASIC, results after irradiation with X-rays to 862 Mrad and neutrons up to 1016(1 MeV neq)/cm2 will be presented. Finally, a brief outlook on further development plans is given.

  4. Follow-up: Prospective compound design using the 'SAR Matrix' method and matrix-derived conditional probabilities of activity.

    PubMed

    Gupta-Ostermann, Disha; Hirose, Yoichiro; Odagami, Takenao; Kouji, Hiroyuki; Bajorath, Jürgen

    2015-01-01

    In a previous Method Article, we have presented the 'Structure-Activity Relationship (SAR) Matrix' (SARM) approach. The SARM methodology is designed to systematically extract structurally related compound series from screening or chemical optimization data and organize these series and associated SAR information in matrices reminiscent of R-group tables. SARM calculations also yield many virtual candidate compounds that form a "chemical space envelope" around related series. To further extend the SARM approach, different methods are developed to predict the activity of virtual compounds. In this follow-up contribution, we describe an activity prediction method that derives conditional probabilities of activity from SARMs and report representative results of first prospective applications of this approach. PMID:25949808

  5. TIME-RESOLVED EMISSION FROM BRIGHT HOT PIXELS OF AN ACTIVE REGION OBSERVED IN THE EUV BAND WITH SDO/AIA AND MULTI-STRANDED LOOP MODELING

    SciTech Connect

    Tajfirouze, E.; Reale, F.; Petralia, A.; Testa, P.

    2016-01-01

    Evidence of small amounts of very hot plasma has been found in active regions and might be an indication of impulsive heating released at spatial scales smaller than the cross-section of a single loop. We investigate the heating and substructure of coronal loops in the core of one such active region by analyzing the light curves in the smallest resolution elements of solar observations in two EUV channels (94 and 335 Å) from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. We model the evolution of a bundle of strands heated by a storm of nanoflares by means of a hydrodynamic 0D loop model (EBTEL). The light curves obtained from a random combination of those of single strands are compared to the observed light curves either in a single pixel or in a row of pixels, simultaneously in the two channels, and using two independent methods: an artificial intelligent system (Probabilistic Neural Network) and a simple cross-correlation technique. We explore the space of the parameters to constrain the distribution of the heat pulses, their duration, their spatial size, and, as a feedback on the data, their signatures on the light curves. From both methods the best agreement is obtained for a relatively large population of events (1000) with a short duration (less than 1 minute) and a relatively shallow distribution (power law with index 1.5) in a limited energy range (1.5 decades). The feedback on the data indicates that bumps in the light curves, especially in the 94 Å channel, are signatures of a heating excess that occurred a few minutes before.

  6. Time-resolved Emission from Bright Hot Pixels of an Active Region Observed in the EUV Band with SDO/AIA and Multi-stranded Loop Modeling

    NASA Astrophysics Data System (ADS)

    Tajfirouze, E.; Reale, F.; Petralia, A.; Testa, P.

    2016-01-01

    Evidence of small amounts of very hot plasma has been found in active regions and might be an indication of impulsive heating released at spatial scales smaller than the cross-section of a single loop. We investigate the heating and substructure of coronal loops in the core of one such active region by analyzing the light curves in the smallest resolution elements of solar observations in two EUV channels (94 and 335 Å) from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. We model the evolution of a bundle of strands heated by a storm of nanoflares by means of a hydrodynamic 0D loop model (EBTEL). The light curves obtained from a random combination of those of single strands are compared to the observed light curves either in a single pixel or in a row of pixels, simultaneously in the two channels, and using two independent methods: an artificial intelligent system (Probabilistic Neural Network) and a simple cross-correlation technique. We explore the space of the parameters to constrain the distribution of the heat pulses, their duration, their spatial size, and, as a feedback on the data, their signatures on the light curves. From both methods the best agreement is obtained for a relatively large population of events (1000) with a short duration (less than 1 minute) and a relatively shallow distribution (power law with index 1.5) in a limited energy range (1.5 decades). The feedback on the data indicates that bumps in the light curves, especially in the 94 Å channel, are signatures of a heating excess that occurred a few minutes before.

  7. Protease induced plasticity: matrix metalloproteinase-1 promotes neurostructural changes through activation of protease activated receptor 1

    PubMed Central

    Allen, Megan; Ghosh, Suhasini; Ahern, Gerard P.; Villapol, Sonia; Maguire-Zeiss, Kathleen A.; Conant, Katherine

    2016-01-01

    Matrix metalloproteinases (MMPs) are a family of secreted endopeptidases expressed by neurons and glia. Regulated MMP activity contributes to physiological synaptic plasticity, while dysregulated activity can stimulate injury. Disentangling the role individual MMPs play in synaptic plasticity is difficult due to overlapping structure and function as well as cell-type specific expression. Here, we develop a novel system to investigate the selective overexpression of a single MMP driven by GFAP expressing cells in vivo. We show that MMP-1 induces cellular and behavioral phenotypes consistent with enhanced signaling through the G-protein coupled protease activated receptor 1 (PAR1). Application of exogenous MMP-1, in vitro, stimulates PAR1 dependent increases in intracellular Ca2+ concentration and dendritic arborization. Overexpression of MMP-1, in vivo, increases dendritic complexity and induces biochemical and behavioral endpoints consistent with increased GPCR signaling. These data are exciting because we demonstrate that an astrocyte-derived protease can influence neuronal plasticity through an extracellular matrix independent mechanism. PMID:27762280

  8. Analytical Model of Water Flow in Coal with Active Matrix

    NASA Astrophysics Data System (ADS)

    Siemek, Jakub; Stopa, Jerzy

    2014-12-01

    This paper presents new analytical model of gas-water flow in coal seams in one dimension with emphasis on interactions between water flowing in cleats and coal matrix. Coal as a flowing system, can be viewed as a solid organic material consisting of two flow subsystems: a microporous matrix and a system of interconnected macropores and fractures. Most of gas is accumulated in the microporous matrix, where the primary flow mechanism is diffusion. Fractures and cleats existing in coal play an important role as a transportation system for macro scale flow of water and gas governed by Darcy's law. The coal matrix can imbibe water under capillary forces leading to exchange of mass between fractures and coal matrix. In this paper new partial differential equation for water saturation in fractures has been formulated, respecting mass exchange between coal matrix and fractures. Exact analytical solution has been obtained using the method of characteristics. The final solution has very simple form that may be useful for practical engineering calculations. It was observed that the rate of exchange of mass between the fractures and the coal matrix is governed by an expression which is analogous to the Newton cooling law known from theory of heat exchange, but in present case the mass transfer coefficient depends not only on coal and fluid properties but also on time and position. The constant term of mass transfer coefficient depends on relation between micro porosity and macro porosity of coal, capillary forces, and microporous structure of coal matrix. This term can be expressed theoretically or obtained experimentally. W artykule zaprezentowano nowy model matematyczny przepływu wody i gazu w jednowymiarowej warstwie węglowej z uwzględnieniem wymiany masy między systemem szczelin i matrycą węglową. Węgiel jako system przepływowy traktowany jest jako układ o podwójnej porowatości i przepuszczalności, składający się z mikroporowatej matrycy węglowej oraz z

  9. Activity of matrix metalloproteinases during antimycobacterial therapy in mice with simulated tuberculous inflammation.

    PubMed

    Sumenkova, D V; Russkikh, G S; Poteryaeva, O N; Polyakov, L M; Panin, L E

    2013-05-01

    Matrix metalloproteinases are shown to be involved in the pathogenesis of tuberculosis inflammation. In the early stages of BCG-granuloma formation in mouse liver and lungs, the serum levels of matrix metalloproteinases 2 and 7 increased by 4.5 times and remained unchanged while the pathology developed. Antimycobacterial therapy with isoniazid reduced enzyme activity almost to the level of intact control. The decrease in activity of matrix metalloproteinases 2 and 7 that play the most prominent role in the development of destructive forms of tuberculosis is of great therapeutic importance.

  10. Selecting Pixels for Kepler Downlink

    NASA Technical Reports Server (NTRS)

    Bryson, Stephen T.; Jenkins, Jon M.; Klaus, Todd C.; Cote, Miles T.; Quintana, Elisa V.; Hall, Jennifer R.; Ibrahim, Khadeejah; Chandrasekaran, Hema; Caldwell, Douglas A.; Van Cleve, Jeffrey E.; Haas, Michael R.

    2010-01-01

    The Kepler mission monitors > 100,000 stellar targets using 42 2200 1024 pixel CCDs. Bandwidth constraints prevent the downlink of all 96 million pixels per 30-minute cadence, so the Kepler spacecraft downlinks a specified collection of pixels for each target. These pixels are selected by considering the object brightness, background and the signal-to-noise of each pixel, and are optimized to maximize the signal-to-noise ratio of the target. This paper describes pixel selection, creation of spacecraft apertures that efficiently capture selected pixels, and aperture assignment to a target. Diagnostic apertures, short-cadence targets and custom specified shapes are discussed.

  11. Activation of Matrix Metalloproteinase-3 is altered at the frog neuromuscular junction following changes in synaptic activity.

    PubMed

    VanSaun, M; Humburg, B C; Arnett, M G; Pence, M; Werle, M J

    2007-09-15

    The extracellular matrix surrounding the neuromuscular junction is a highly specialized and dynamic structure. Matrix Metalloproteinases are enzymes that sculpt the extracellular matrix. Since synaptic activity is critical to the structure and function of this synapse, we investigated whether changes in synaptic activity levels could alter the activity of Matrix Metalloproteinases at the neuromuscular junction. In particular, we focused on Matrix Metalloproteinase 3 (MMP3), since antibodies to MMP3 recognize molecules at the frog neuromuscular junction, and MMP3 cleaves a number of synaptic basal lamina molecules, including agrin. Here we show that the fluorogenic compound (M2300) can be used to perform in vivo proteolytic imaging of the frog neuromuscular junction to directly measure the activity state of MMP3. Application of this compound reveals that active MMP3 is concentrated at the normal frog neuromuscular junction, and is tightly associated with the terminal Schwann cell. Blocking presynaptic activity via denervation, or TTX nerve blockade, results in a decreased level of active MMP3 at the neuromuscular junction. The loss of active MMP3 at the neuromuscular junction in denervated muscles can result from decreased activation of pro-MMP3, or it could result from increased inhibition of MMP3. These results support the hypothesis that changes in synaptic activity can alter the level of active MMP3 at the neuromuscular junction. PMID:17525979

  12. ASTM and VAMAS activities in titanium matrix composites test methods development

    NASA Technical Reports Server (NTRS)

    Johnson, W. S.; Harmon, D. M.; Bartolotta, P. A.; Russ, S. M.

    1994-01-01

    Titanium matrix composites (TMC's) are being considered for a number of aerospace applications ranging from high performance engine components to airframe structures in areas that require high stiffness to weight ratios at temperatures up to 400 C. TMC's exhibit unique mechanical behavior due to fiber-matrix interface failures, matrix cracks bridged by fibers, thermo-viscoplastic behavior of the matrix at elevated temperatures, and the development of significant thermal residual stresses in the composite due to fabrication. Standard testing methodology must be developed to reflect the uniqueness of this type of material systems. The purpose of this paper is to review the current activities in ASTM and Versailles Project on Advanced Materials and Standards (VAMAS) that are directed toward the development of standard test methodology for titanium matrix composites.

  13. pH-Sensitive Microparticles with Matrix-Dispersed Active Agent

    NASA Technical Reports Server (NTRS)

    Li, Wenyan (Inventor); Buhrow, Jerry W. (Inventor); Jolley, Scott T. (Inventor); Calle, Luz M. (Inventor)

    2014-01-01

    Methods to produce pH-sensitive microparticles that have an active agent dispersed in a polymer matrix have certain advantages over microcapsules with an active agent encapsulated in an interior compartment/core inside of a polymer wall. The current invention relates to pH-sensitive microparticles that have a corrosion-detecting or corrosion-inhibiting active agent or active agents dispersed within a polymer matrix of the microparticles. The pH-sensitive microparticles can be used in various coating compositions on metal objects for corrosion detecting and/or inhibiting.

  14. Planar slim-edge pixel sensors for the ATLAS upgrades

    NASA Astrophysics Data System (ADS)

    Altenheiner, S.; Goessling, C.; Jentzsch, J.; Klingenberg, R.; Lapsien, T.; Muenstermann, D.; Rummler, A.; Troska, G.; Wittig, T.

    2012-02-01

    The ATLAS detector at CERN is a general-purpose experiment at the Large Hadron Collider (LHC). The ATLAS Pixel Detector is the innermost tracking detector of ATLAS and requires a sufficient level of hermeticity to achieve superb track reconstruction performance. The current planar n-type pixel sensors feature a pixel matrix of n+-implantations which is (on the opposite p-side) surrounded by so-called guard rings to reduce the high voltage stepwise towards the cutting edge and an additional safety margin. Because of the inactive region around the active area, the sensor modules have been shingled on top of each other's edge which limits the thermal performance and adds complexity in the present detector. The first upgrade phase of the ATLAS pixel detector will consist of the insertable b-layer (IBL), an additional b-layer which will be inserted into the present detector in 2013. Several changes in the sensor design with respect to the existing detector had to be applied to comply with the IBL's specifications and are described in detail. A key issue for the ATLAS upgrades is a flat arrangement of the sensors. To maintain the required level of hermeticity in the detector, the inactive sensor edges have to be reduced to minimize the dead space between the adjacent detector modules. Unirradiated and irradiated sensors with the IBL design have been operated in test beams to study the efficiency performance in the sensor edge region and it was found that the inactive edge width could be reduced from 1100 μm to less than 250 μm.

  15. Improvement in Brightness Uniformity by Compensating for the Threshold Voltages of Both the Driving Thin-Film Transistor and the Organic Light-Emitting Diode for Active-Matrix Organic Light-Emitting Diode Displays

    NASA Astrophysics Data System (ADS)

    Fan, Ching-Lin; Lai, Hui-Lung; Chang, Jyu-Yu

    2010-05-01

    In this paper, we propose a novel pixel design and driving method for active-matrix organic light-emitting diode (AM-OLED) displays using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). The proposed threshold voltage compensation circuit, which comprised five transistors and two capacitors, has been verified to supply uniform output current by simulation work using the automatic integrated circuit modeling simulation program with integrated circuit emphasis (AIM-SPICE) simulator. The driving scheme of this voltage programming method includes four periods: precharging, compensation, data input, and emission. The simulated results demonstrate excellent properties such as low error rate of OLED anode voltage variation (<1%) and high output current. The proposed pixel circuit shows high immunity to the threshold voltage deviation characteristics of both the driving poly-Si TFT and the OLED.

  16. Novel Driving Method for Two-Dimensional and Three-Dimensional Switchable Active Matrix Organic Light-Emitting Diode Displays for Emission and Programming Time Extension

    NASA Astrophysics Data System (ADS)

    In, Hai-Jung; Kwon, Oh-Kyong

    2012-03-01

    A novel driving method for two-dimensional (2D) and three-dimensional (3D) switchable active matrix organic light-emitting diode (AMOLED) displays is proposed to extend emission time and data programming time during 3D display operation. The proposed pixel consists of six thin-film transistors (TFTs) and two capacitors, and the aperture ratio of the pixel is 45.8% under 40-in. full-high-definition television condition. By increasing emission time and programming time, the flicker problem can be reduced and the lifetime of AMOLED displays can be extended owing to the decrease in emission current density. Simulation results show that the emission current error range from -0.4 to 1.6% is achieved when the threshold voltage variation of driving TFTs is in the range from -1.0 to 1.0 V, and the emission current error is 1.0% when the power line IR-drop is 2.0 V.

  17. Matrix Rigidity Activates Wnt Signaling through Down-regulation of Dickkopf-1 Protein*

    PubMed Central

    Barbolina, Maria V.; Liu, Yiuying; Gurler, Hilal; Kim, Mijung; Kajdacsy-Balla, Andre A.; Rooper, Lisa; Shepard, Jaclyn; Weiss, Michael; Shea, Lonnie D.; Penzes, Peter; Ravosa, Matthew J.; Stack, M. Sharon

    2013-01-01

    Cells respond to changes in the physical properties of the extracellular matrix with altered behavior and gene expression, highlighting the important role of the microenvironment in the regulation of cell function. In the current study, culture of epithelial ovarian cancer cells on three-dimensional collagen I gels led to a dramatic down-regulation of the Wnt signaling inhibitor dickkopf-1 with a concomitant increase in nuclear β-catenin and enhanced β-catenin/Tcf/Lef transcriptional activity. Increased three-dimensional collagen gel invasion was accompanied by transcriptional up-regulation of the membrane-tethered collagenase membrane type 1 matrix metalloproteinase, and an inverse relationship between dickkopf-1 and membrane type 1 matrix metalloproteinase was observed in human epithelial ovarian cancer specimens. Similar results were obtained in other tissue-invasive cells such as vascular endothelial cells, suggesting a novel mechanism for functional coupling of matrix adhesion with Wnt signaling. PMID:23152495

  18. Responsibility modulates pain-matrix activation elicited by the expressions of others in pain.

    PubMed

    Cui, Fang; Abdelgabar, Abdel-Rahman; Keysers, Christian; Gazzola, Valeria

    2015-07-01

    Here we examine whether brain responses to dynamic facial expressions of pain are influenced by our responsibility for the observed pain. Participants played a flanker task with a confederate. Whenever either erred, the confederate was seen to receive a noxious shock. Using functional magnetic resonance imaging, we found that regions of the functionally localized pain-matrix of the participants (the anterior insula in particular) were activated most strongly when seeing the confederate receive a noxious shock when only the participant had erred (and hence had full responsibility). When both or only the confederate had erred (i.e. participant's shared or no responsibility), significantly weaker vicarious pain-matrix activations were measured.

  19. Method and apparatus of high dynamic range image sensor with individual pixel reset

    NASA Technical Reports Server (NTRS)

    Yadid-Pecht, Orly (Inventor); Pain, Bedabrata (Inventor); Fossum, Eric R. (Inventor)

    2001-01-01

    A wide dynamic range image sensor provides individual pixel reset to vary the integration time of individual pixels. The integration time of each pixel is controlled by column and row reset control signals which activate a logical reset transistor only when both signals coincide for a given pixel.

  20. Matrix fibronectin disruption and altered endothelial cell adhesion induced by activated leukocytes

    SciTech Connect

    Vincent, P.; Richards, P.; Saba, T.; DelVecchio, P.

    1986-03-01

    Sequestration of activated leukocytes (PMN) within the lung may contribute to pulmonary vascular injury following trauma, sepsis, or intravascular coagulation. Monolayers of cultured rat endothelial cells were utilized to evaluate the effect of activated PMNs on endothelial cell attachment and the extracellular fibronectin matrix over a 4 hr incubation interval. Rat endothelial cells were identified by immunofluorescent staining of Factor VIII R:Ag. Endothelial cells were labeled with /sup 51/Cr in order to establish a cell injury assay in which the release of pelletable (cell associated) or non-pelletable activity was measured in the media. PMN activation was verified by chemiluminescence activity. Following phorbol myristate acetate (PMA) the leukocytes aggregated, chemiluminesced, and caused detachment of /sup 51/Cr endothelial cells. Endothelial detachment increased as a function of time with a plateau by 3 hrs. Immunofluorescent analysis of extracellular fibronectin in endothelial cell cultures revealed disruption of the fibrillar matrix fibronectin in association with endothelial cell disadhesion. Matrix fibronectin disruption was not seen with PMNs or PMA alone. Thus, disruption of the fibronectin matrix by released proteases may contribute to endothelial cell detachment.

  1. From hybrid to CMOS pixels ... a possibility for LHC's pixel future?

    NASA Astrophysics Data System (ADS)

    Wermes, N.

    2015-12-01

    Hybrid pixel detectors have been invented for the LHC to make tracking and vertexing possible at all in LHC's radiation intense environment. The LHC pixel detectors have meanwhile very successfully fulfilled their promises and R&D for the planned HL-LHC upgrade is in full swing, targeting even higher ionising doses and non-ionising fluences. In terms of rate and radiation tolerance hybrid pixels are unrivaled. But they have disadvantages as well, most notably material thickness, production complexity, and cost. Meanwhile also active pixel sensors (DEPFET, MAPS) have become real pixel detectors but they would by far not stand the rates and radiation faced from HL-LHC. New MAPS developments, so-called DMAPS (depleted MAPS) which are full CMOS-pixel structures with charge collection in a depleted region have come in the R&D focus for pixels at high rate/radiation levels. This goal can perhaps be realised exploiting HV technologies, high ohmic substrates and/or SOI based technologies. The paper covers the main ideas and some encouraging results from prototyping R&D, not hiding the difficulties.

  2. Nobiletin metabolites: synthesis and inhibitory activity against matrix metalloproteinase-9 production.

    PubMed

    Oshitari, Tetsuta; Okuyama, Yuji; Miyata, Yoshiki; Kosano, Hiroshi; Takahashi, Hideyo; Natsugari, Hideaki

    2011-08-01

    A divergent synthesis of nobiletin metabolites was developed through highly oxygenated acetophenone derivative. We used commercially available methyl 3,4,5-trimethoxybenzoate as a starting material for concise preparation of the key intermediate, 2'-hydroxy-3',4',5',6'-tetramethoxyacetophenone (I). These metabolites showed strong inhibitory activity against matrix metalloproteinase-9 production in human lens epithelial cells.

  3. Pixel Dynamics Analysis of Photospheric Spectral Data

    NASA Astrophysics Data System (ADS)

    Rasca, Anthony P.; Chen, James; Pevtsov, Alexei A.

    2015-04-01

    Recent advances in solar observations have led to higher-resolution surface (photosphere) images that reveal bipolar magnetic features operating near the resolution limit during emerging flux events. Further improvements in resolution are expected to reveal even smaller dynamic features. Such photospheric features provide observable indications of what is happening before, during, and after flux emergence, eruptions in the corona, and other phenomena. Visible changes in photospheric active regions also play a major role in predicting eruptions that are responsible for geomagnetic plasma disturbances. A new method has been developed to extract physical information from photospheric data (e.g., SOLIS Stokes parameters) based on the statistics of pixel-by-pixel variations in spectral (absorption or emission) line quantities such as line profile Doppler shift, width, asymmetry, and flatness. Such properties are determined by the last interaction between detected photons and optically thick photospheric plasmas, and may contain extractable information on local plasma properties at sub-pixel scales. Applying the method to photospheric data with high spectral resolution, our pixel-by-pixel analysis is performed for various regions on the solar disk, ranging from quiet-Sun regions to active regions exhibiting eruptions, characterizing photospheric dynamics using spectral profiles. In particular, the method quantitatively characterizes the time profile of changes in spectral properties in photospheric features and provides improved physical constraints on observed quantities.

  4. Bacterial lipopolysaccharides induce in vitro degradation of cartilage matrix through chondrocyte activation.

    PubMed

    Jasin, H E

    1983-12-01

    The present studies demonstrate that bacterial lipopolysaccharides (LPS) induce cartilage matrix degradation in live explants in organ culture. Quintuplicate bovine nasal fibrocartilage explants cultured for 8 d with three different purified LPS preparations derived from Escherichia coli and Salmonella typhosa at concentrations ranging from 1.0 to 25.0 micrograms/ml resulted in matrix proteoglycan depletion of 33.3 +/- 5.8 to 92.5 +/- 2.0% (medium control depletion 17.7 +/- 0.7 to 32.4 +/- 1.4%). Matrix degradation depended on the presence of live chondrocytes because frozen-thawed explants incubated with LPS failed to show any proteoglycan release. Moreover, the addition of Polymyxin B (25 micrograms/ml) to live explants incubated with LPS abolished matrix release, whereas Polymyxin B had no effect on the matrix-degrading activity provided by blood mononuclear cell factors. A highly purified Lipid A preparation induced matrix degradation at a concentration of 0.01 micrograms/ml. Cartilage matrix collagen and proteoglycan depletion also occurred with porcine articular cartilage explants (collagen release: 18.3 +/- 3.5%, medium control: 2.1 +/- 0.5%; proteoglycan release: 79.0 +/- 5.9%, medium control: 28.8 +/- 4.8%). Histochemical analysis of the cultured explants confirmed the results described above. Gel chromatography of the proteoglycans released in culture indicated that LPS induced significant degradation of the high molecular weight chondroitin sulfate-containing aggregates. These findings suggest that bacterial products may induce cartilage damage by direct stimulation of chondrocytes. This pathogenic mechanism may play a role in joint damage in septic arthritis and in arthropathies resulting from the presence of bacterial products derived from the gastrointestinal tract.

  5. Commissioning of the ATLAS pixel detector

    SciTech Connect

    ATLAS Collaboration; Golling, Tobias

    2008-09-01

    The ATLAS pixel detector is a high precision silicon tracking device located closest to the LHC interaction point. It belongs to the first generation of its kind in a hadron collider experiment. It will provide crucial pattern recognition information and will largely determine the ability of ATLAS to precisely track particle trajectories and find secondary vertices. It was the last detector to be installed in ATLAS in June 2007, has been fully connected and tested in-situ during spring and summer 2008, and is ready for the imminent LHC turn-on. The highlights of the past and future commissioning activities of the ATLAS pixel system are presented.

  6. Activity-based labeling of matrix metalloproteinases in living vertebrate embryos.

    PubMed

    Keow, Jonathan Y; Pond, Eric D; Cisar, Justin S; Cravatt, Benjamin F; Crawford, Bryan D

    2012-01-01

    Extracellular matrix (ECM) remodeling is a physiologically and developmentally essential process mediated by a family of zinc-dependent extracellular proteases called matrix metalloproteinases (MMPs). In addition to complex transcriptional control, MMPs are subject to extensive post-translational regulation. Because of this, classical biochemical, molecular and histological techniques that detect the expression of specific gene products provide useful but limited data regarding the biologically relevant activity of MMPs. Using benzophenone-bearing hydroxamate-based probes that interact with the catalytic zinc ion in MMPs, active proteases can be covalently 'tagged' by UV cross-linking. This approach has been successfully used to tag MMP-2 in vitro in tissue culture supernatants, and we show here that this probe tags proteins with mobilities consistent with known MMPs and detectable gelatinolytic activity in homogenates of zebrafish embryos. Furthermore, because of the transparency of the zebrafish embryo, UV-photocroslinking can be accomplished in vivo, and rhodamated benzophenone probe is detected in striking spatial patterns consistent with known distributions of active matrix remodeling in embryos. Finally, in metamorphosing Xenopus tadpoles, this probe can be used to biotinylate active MMP-2 by injecting it and cross-linking it in vivo, allowing the protein to be subsequently extracted and biochemically identified. PMID:22952682

  7. Synovial fluid matrix metalloproteinase-2 and -9 activities in dogs suffering from joint disorders

    PubMed Central

    MURAKAMI, Kohei; MAEDA, Shingo; YONEZAWA, Tomohiro; MATSUKI, Naoaki

    2016-01-01

    The activity of matrix metalloproteinase (MMP)-2 and MMP-9 in synovial fluids (SF) sampled from dogs with joint disorders was investigated by gelatin zymography and densitometry. Pro-MMP-2 showed similar activity levels in dogs with idiopathic polyarthritis (IPA; n=17) or canine rheumatoid arthritis (cRA; n=4), and healthy controls (n=10). However, dogs with cranial cruciate ligament rupture (CCLR; n=5) presented significantly higher pro-MMP-2 activity than IPA and healthy dogs. Meanwhile, dogs with IPA exhibited significantly higher activity of pro- and active MMP-9 than other groups. Activity levels in pro- and active MMP-9 in cRA and CCLR dogs were not significantly different from those in healthy controls. Different patterns of MMP-2 and MMP-9 activity may reflect the differences in the underlying pathological processes. PMID:26902805

  8. Pixelation Effects in Weak Lensing

    NASA Astrophysics Data System (ADS)

    High, F. William; Rhodes, Jason; Massey, Richard; Ellis, Richard

    2007-11-01

    Weak gravitational lensing can be used to investigate both dark matter and dark energy but requires accurate measurements of the shapes of faint, distant galaxies. Such measurements are hindered by the finite resolution and pixel scale of digital cameras. We investigate the optimum choice of pixel scale for a space-based mission, using the engineering model and survey strategy of the proposed Supernova Acceleration Probe as a baseline. We do this by simulating realistic astronomical images containing a known input shear signal and then attempting to recover the signal using the Rhodes, Refregier, & Groth algorithm. We find that the quality of shear measurement is always improved by smaller pixels. However, in practice, telescopes are usually limited to a finite number of pixels and operational life span, so the total area of a survey increases with pixel size. We therefore fix the survey lifetime and the number of pixels in the focal plane while varying the pixel scale, thereby effectively varying the survey size. In a pure trade-off for image resolution versus survey area, we find that measurements of the matter power spectrum would have minimum statistical error with a pixel scale of 0.09" for a 0.14" FWHM point-spread function (PSF). The pixel scale could be increased to ~0.16" if images dithered by exactly half-pixel offsets were always available. Some of our results do depend on our adopted shape measurement method and should be regarded as an upper limit: future pipelines may require smaller pixels to overcome systematic floors not yet accessible, and, in certain circumstances, measuring the shape of the PSF might be more difficult than those of galaxies. However, the relative trends in our analysis are robust, especially those of the surface density of resolved galaxies. Our approach thus provides a snapshot of potential in available technology, and a practical counterpart to analytic studies of pixelation, which necessarily assume an idealized shape

  9. Design of a silicon avalanche photodiode pixel with integrated laser diode using back-illuminated crystallographically etched silicon-on-sapphire with monolithically integrated microlens for dual-mode passive and active imaging arrays

    NASA Astrophysics Data System (ADS)

    Stern, Alvin G.

    2010-08-01

    There is a growing need in scientific research applications for dual-mode, passive and active 2D and 3D LADAR imaging methods. To fill this need, an advanced back-illuminated silicon avalanche photodiode (APD) design is presented using a novel silicon-on-sapphire substrate incorporating a crystalline aluminum nitride (AlN) antireflective layer between the silicon and R-plane sapphire. This allows integration of a high quantum efficiency silicon APD with a gallium nitride (GaN) laser diode in each pixel. The pixel design enables single photon sensitive, solid-state focal plane arrays (FPAs) with wide dynamic range, supporting passive and active imaging capability in a single FPA. When (100) silicon is properly etched with TMAH solution, square based pyramidal frustum or mesa arrays result with the four mesa sidewalls of the APD formed by (111) silicon planes that intersect the (100) planes at a crystallographic angle, φ c = 54.7°. The APD device is fabricated in the mesa using conventional silicon processing technology. The GaN laser diode is fabricated by epitaxial growth inside of an inverted, etched cavity in the silicon mesa. Microlenses are fabricated in the thinned, and AR-coated sapphire substrate. The APDs share a common, front-side anode contact, and laser diodes share a common cathode. A low resistance (Al) or (Cu) metal anode grid fills the space between pixels and also inhibits optical crosstalk. SOS-APD arrays are flip-chip bump-bonded to CMOS readout ICs to produce hybrid FPAs. The square 27 μm emitter-detector pixel achieves SNR > 1 in active detection mode for Lambert surfaces at 1,000 meters.

  10. Angiostatin inhibits endothelial and melanoma cellular invasion by blocking matrix-enhanced plasminogen activation.

    PubMed Central

    Stack, M S; Gately, S; Bafetti, L M; Enghild, J J; Soff, G A

    1999-01-01

    Angiostatin, a kringle-containing fragment of plasminogen, is a potent inhibitor of angiogenesis. The mechanism(s) responsible for the anti-angiogenic properties of angiostatin are unknown. We now report that human angiostatin blocks plasmin(ogen)-enhanced in vitro invasion of tissue plasminogen activator (t-PA)-producing endothelial and melanoma cells. Kinetic analyses demonstrated that angiostatin functions as a non-competitive inhibitor of extracellular-matrix (ECM)-enhanced, t-PA-catalysed plasminogen activation, with a Ki of 0.9+/-0.03 microM. This mechanism suggests that t-PA has a binding site for the inhibitor angiostatin, as well as for its substrate plasminogen that, when occupied, prevents ternary complex formation between t-PA, plasminogen and matrix protein. Direct binding experiments confirmed that angiostatin bound to t-PA with an apparent Kd [Kd(app)] of 6.7+/-0.7 nM, but did not bind with high affinity to ECM proteins. Together, these data suggest that angiostatin in the cellular micro-environment can inhibit matrix-enhanced plasminogen activation, resulting in reduced invasive activity, and suggest a biochemical mechanism whereby angiostatin-mediated regulation of plasmin formation could influence cellular migration and invasion. PMID:10229661

  11. Involvement of matrix metalloproteinase activity in hormone-induced mammary tumor regression.

    PubMed

    Simian, Marina; Molinolo, Alfredo; Lanari, Claudia

    2006-01-01

    Proteolytic activity and remodeling of the extracellular matrix are important players in tumor progression. However, to date the role of the extracellular matrix in tumor regression remains unresolved. To address this, we used a progesterone-dependent in vivo mouse mammary tumor line, C4-HD, which regresses in response to hormone therapy. Within the first 72 hours of treatment, massive apoptosis was accompanied by changes in the staining patterns of laminin and collagens I, III, and IV. We thus hypothesized that an increase in matrix metalloproteinase (MMP) activity could be involved in this process. This indeed was the case as the activities of MMP-2, -9, and -3 increased in regressing tumors, coinciding with the peak of apoptosis. Moreover, cell-cell interactions were disrupted during early hours of regression with E-cadherin levels reduced and fragmentation products detected during regression. Analysis of beta-catenin revealed that although total levels within the tissue did not change, this molecule switched from being involved in cell-cell adhesion in the growing tumor to being expressed in the reactive stroma during regression. Our data provide a novel role for proteolytic activity in tumor regression and question the underlying principle for using MMP inhibitors in cancer treatment. PMID:16400029

  12. Communication: Active space decomposition with multiple sites: Density matrix renormalization group algorithm

    SciTech Connect

    Parker, Shane M.; Shiozaki, Toru

    2014-12-07

    We extend the active space decomposition method, recently developed by us, to more than two active sites using the density matrix renormalization group algorithm. The fragment wave functions are described by complete or restricted active-space wave functions. Numerical results are shown on a benzene pentamer and a perylene diimide trimer. It is found that the truncation errors in our method decrease almost exponentially with respect to the number of renormalization states M, allowing for numerically exact calculations (to a few μE{sub h} or less) with M = 128 in both cases. This rapid convergence is because the renormalization steps are used only for the interfragment electron correlation.

  13. Activation of AMPK Prevents Monocrotaline-Induced Extracellular Matrix Remodeling of Pulmonary Artery

    PubMed Central

    Li, Shaojun; Han, Dong; Zhang, Yonghong; Xie, Xinming; Ke, Rui; Zhu, Yanting; Liu, Lu; Song, Yang; Yang, Lan; Li, Manxiang

    2016-01-01

    Background The current study was performed to investigate the effect of adenosine monophosphate (AMP) – activated protein kinase (AMPK) activation on the extracellular matrix (ECM) remodeling of pulmonary arteries in pulmonary arterial hypertension (PAH) and to address its potential mechanisms. Material/Methods PAH was induced by a single intraperitoneal injection of monocrotaline (MCT) into Sprague-Dawley rats. Metformin (MET) was administered to activate AMPK. Immunoblotting was used to determine the phosphorylation and expression of AMPK and expression of tissue inhibitor of metalloproteinase-1 (TIMP-1). Gelatin zymography was performed to determine the activity of matrix metalloproteinase-2 (MMP-2) and MMP-9. Results Activation of AMPK by MET significantly reduced the right ventricle systolic pressure and the right ventricular hypertrophy in MCT-induced rat PAH model, and partially inhibited the ECM remodeling of pulmonary arteries. These effects were coupled with the decrease of MMP-2/9 activity and TIMP-1 expression. Conclusions This study suggests that activation of AMPK benefits PAH by inhibiting ECM remodeling of pulmonary arteries. Enhancing AMPK activity might have potential value in clinical treatment of PAH. PMID:26978596

  14. Urinary matrix metalloproteinase activities: biomarkers for plaque angiogenesis and nephropathy in diabetes.

    PubMed

    McKittrick, Ian B; Bogaert, Yolanda; Nadeau, Kristen; Snell-Bergeon, Janet; Hull, Amber; Jiang, Tao; Wang, Xiaoxin; Levi, Moshe; Moulton, Karen S

    2011-12-01

    Diabetic complications of nephropathy and accelerated atherosclerosis are associated with vascular remodeling and dysregulated angiogenesis. Matrix metalloproteinases (MMP) modify extracellular matrix during vascular remodeling and are excreted in urine of patients with vascular malformation or tumor angiogenesis. We hypothesized that urinary MMP activities would be sensitive biomarkers for vascular remodeling in diabetic complications. Activities of MMP-2, MMP-9, and its complex with neutrophil gelatinase-associated lipocalin (NGAL/MMP-9) were measured by substrate gel zymography in urine from nondiabetic (ND) and type 1 diabetic (T1D) rodents that were susceptible to both T1D-induced plaque angiogenesis and nephropathy, or nephropathy alone. Additionally, these urine activities were measured in ND and T1D adolescents. Urinary MMP-9, MMP-2, and NGAL/MMP-9 activities were increased and more prevalent in T1D compared with ND controls. Urinary MMP-2 activity was detected in mice with T1D-induced plaque neovascularization. In nephropathy models, urinary NGAL/MMP-9 and MMP-9 activities appeared before onset of albuminuria, whereas MMP-2 was absent or delayed. Finally, urinary MMP activities were increased in adolescents with early stages of T1D. Urinary MMP activities may be sensitive, noninvasive, and clinically useful biomarkers for predicting vascular remodeling in diabetic renal and vascular complications. PMID:21921021

  15. Urinary matrix metalloproteinase activities: biomarkers for plaque angiogenesis and nephropathy in diabetes

    PubMed Central

    McKittrick, Ian B.; Bogaert, Yolanda; Nadeau, Kristen; Snell-Bergeon, Janet; Hull, Amber; Jiang, Tao; Wang, Xiaoxin; Levi, Moshe

    2011-01-01

    Diabetic complications of nephropathy and accelerated atherosclerosis are associated with vascular remodeling and dysregulated angiogenesis. Matrix metalloproteinases (MMP) modify extracellular matrix during vascular remodeling and are excreted in urine of patients with vascular malformation or tumor angiogenesis. We hypothesized that urinary MMP activities would be sensitive biomarkers for vascular remodeling in diabetic complications. Activities of MMP-2, MMP-9, and its complex with neutrophil gelatinase-associated lipocalin (NGAL/MMP-9) were measured by substrate gel zymography in urine from nondiabetic (ND) and type 1 diabetic (T1D) rodents that were susceptible to both T1D-induced plaque angiogenesis and nephropathy, or nephropathy alone. Additionally, these urine activities were measured in ND and T1D adolescents. Urinary MMP-9, MMP-2, and NGAL/MMP-9 activities were increased and more prevalent in T1D compared with ND controls. Urinary MMP-2 activity was detected in mice with T1D-induced plaque neovascularization. In nephropathy models, urinary NGAL/MMP-9 and MMP-9 activities appeared before onset of albuminuria, whereas MMP-2 was absent or delayed. Finally, urinary MMP activities were increased in adolescents with early stages of T1D. Urinary MMP activities may be sensitive, noninvasive, and clinically useful biomarkers for predicting vascular remodeling in diabetic renal and vascular complications. PMID:21921021

  16. In vivo detecting matrix metalloproteinase (MMP) activity by a genetically engineered fluorescent probe

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Zhang, Zhihong; Su, Ting; Luo, Qingming

    2007-02-01

    Degradation of the extracellular matrix (ECM) by matrix metalloproteinases (MMPs) enhances tumor invasion and metastasis. To monitor MMP activity, we constructed plasmid that encoded a fluorescent sensor DC, in which an MMP substrate site (MSS) is sandwiched between DsRed2 and ECFP. MMPs are secretory proteins, only acting on the outside of cells; hence, an expressing vector was used that displayed the fluorescent sensor on the cellular surface. The DC was expressed in cells with high secretory MMP, so MSS was cleaved by MMP. Also, GM6001, an MMP inhibitor, causes DsRed2 signals to increase in living cells and on the chick embryo chorioallantoic membrane (CAM). Thus, this fluorescent sensor was able to sensitively monitor MMP activation in vivo. Potential applications for this sensor include high-throughput screening for MMP inhibitors for anti-cancer research, and detailed analysis of the effects of MMP inhibitors.

  17. Design methodology: edgeless 3D ASICs with complex in-pixel processing for pixel detectors

    SciTech Connect

    Fahim Farah, Fahim Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

    2015-08-28

    The design methodology for the development of 3D integrated edgeless pixel detectors with in-pixel processing using Electronic Design Automation (EDA) tools is presented. A large area 3 tier 3D detector with one sensor layer and two ASIC layers containing one analog and one digital tier, is built for x-ray photon time of arrival measurement and imaging. A full custom analog pixel is 65μm x 65μm. It is connected to a sensor pixel of the same size on one side, and on the other side it has approximately 40 connections to the digital pixel. A 32 x 32 edgeless array without any peripheral functional blocks constitutes a sub-chip. The sub-chip is an indivisible unit, which is further arranged in a 6 x 6 array to create the entire 1.248cm x 1.248cm ASIC. Each chip has 720 bump-bond I/O connections, on the back of the digital tier to the ceramic PCB. All the analog tier power and biasing is conveyed through the digital tier from the PCB. The assembly has no peripheral functional blocks, and hence the active area extends to the edge of the detector. This was achieved by using a few flavors of almost identical analog pixels (minimal variation in layout) to allow for peripheral biasing blocks to be placed within pixels. The 1024 pixels within a digital sub-chip array have a variety of full custom, semi-custom and automated timing driven functional blocks placed together. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout. The methodology uses the Cadence design platform, however it is not limited to this tool.

  18. Proton Channel Activity of Influenza A Virus Matrix Protein 2 Contributes to Autophagy Arrest

    PubMed Central

    Ren, Yizhong; Feng, Liqiang; Pan, Weiqi; Li, Liang; Wang, Qian; Li, Jiashun; Li, Na; Han, Ling; Zheng, Xuehua; Niu, Xuefeng; Sun, Caijun

    2015-01-01

    Influenza A virus infection can arrest autophagy, as evidenced by autophagosome accumulation in infected cells. Here, we report that this autophagosome accumulation can be inhibited by amantadine, an antiviral proton channel inhibitor, in amantadine-sensitive virus infected cells or cells expressing influenza A virus matrix protein 2 (M2). Thus, M2 proton channel activity plays a role in blocking the fusion of autophagosomes with lysosomes, which might be a key mechanism for arresting autophagy. PMID:26468520

  19. Implementation of advanced matrix corrections for active interrogation of waste drums using the CTEN instrument

    SciTech Connect

    Melton, S.; Estep, R.; Hollas, C.

    1998-12-31

    The combined thermal/epithermal neutron instrument (CTEN) was designed at Los Alamos to improve measurement accuracy and mitigate self shielding effects inherent in the differential dieaway technique (DDT). A major goal in this research effort has been the development of a calibration technique that incorporates recently developed matrix and self-shielding corrections using data generated from additional detectors and new acquisition techniques. A comprehensive data set containing both active and passive measurements was generated using 26 different matrices and comprising a total of 1,400 measurements. In all, 31 flux-and-matrix-dependent parameters, 24 positional parameters, two dieaway times, and a correlated ratio were determined from each of the over 1,400 measurements. A reduced list of matrix indicators, prioritized using the alternating conditional expectation (ACE) algorithm, was used to train a neural network using a generalized regression technique (GRNN) to determine matrix- and position-corrected calibration factors. This paper describes the experimental, analytical, and empirical techniques used to determine the corrected calibration factor for an unknown waste drum. Results from a range of cases are compared with those obtained using a mobile DDT instrument and traditional DDT algorithms.

  20. Active-matrix organic light-emitting diode displays on flexible metal foil substrates

    NASA Astrophysics Data System (ADS)

    Chuang, Ta-Ko

    This dissertation presents the research efforts that deal with the development of polysilicon thin film transistors (TFTs) on stainless-steel-foil substrates, the implementation of high-resolution flexible active-matrix backplanes, and the integration of the flexible polysilicon TFT backplanes with polymer light-emitting diodes. This research investigated the preparation of the steel foil substrates, the fabrication of flexible polysilicon TFT backplanes and polymer light emitting diodes (PLEDs), and the encapsulation of the flexible Active Matrix Polymer Light Emitting Diode displays. The first successful integration of polysilicon TFT backplane with PLEDs onto light-weight, robust, and flexible stainless-steel-foil substrates is presented. A top-emitting, monochrome active-matrix polymer light-emitting diode (AM-PLED) display, having the VGA (640x480) format and a 230 dpi resolution, is demonstrated for the first time on flexible stainless-steel-foil substrates. This work validates the compatibility of the polysilicon technology for high-resolution flexible AM-PLED displays. Furthermore, this work shows that a variety of other large-area microelectronics could also be implemented onto flexible metal foils, benefiting by the metal oil dimensional stability and ability to withstand high process temperature. In conclusion, the polysilicon TFT technology combining with metal-foil substrates opens up a new road for flexible displays as well as large-area flexible electronic applications.

  1. Matrix stiffness modulates formation and activity of neuronal networks of controlled architectures.

    PubMed

    Lantoine, Joséphine; Grevesse, Thomas; Villers, Agnès; Delhaye, Geoffrey; Mestdagh, Camille; Versaevel, Marie; Mohammed, Danahe; Bruyère, Céline; Alaimo, Laura; Lacour, Stéphanie P; Ris, Laurence; Gabriele, Sylvain

    2016-05-01

    The ability to construct easily in vitro networks of primary neurons organized with imposed topologies is required for neural tissue engineering as well as for the development of neuronal interfaces with desirable characteristics. However, accumulating evidence suggests that the mechanical properties of the culture matrix can modulate important neuronal functions such as growth, extension, branching and activity. Here we designed robust and reproducible laminin-polylysine grid micropatterns on cell culture substrates that have similar biochemical properties but a 100-fold difference in Young's modulus to investigate the role of the matrix rigidity on the formation and activity of cortical neuronal networks. We found that cell bodies of primary cortical neurons gradually accumulate in circular islands, whereas axonal extensions spread on linear tracks to connect circular islands. Our findings indicate that migration of cortical neurons is enhanced on soft substrates, leading to a faster formation of neuronal networks. Furthermore, the pre-synaptic density was two times higher on stiff substrates and consistently the number of action potentials and miniature synaptic currents was enhanced on stiff substrates. Taken together, our results provide compelling evidence to indicate that matrix stiffness is a key parameter to modulate the growth dynamics, synaptic density and electrophysiological activity of cortical neuronal networks, thus providing useful information on scaffold design for neural tissue engineering.

  2. THE KEPLER PIXEL RESPONSE FUNCTION

    SciTech Connect

    Bryson, Stephen T.; Haas, Michael R.; Dotson, Jessie L.; Koch, David G.; Borucki, William J.; Tenenbaum, Peter; Jenkins, Jon M.; Chandrasekaran, Hema; Caldwell, Douglas A.; Klaus, Todd; Gilliland, Ronald L.

    2010-04-20

    Kepler seeks to detect sequences of transits of Earth-size exoplanets orbiting solar-like stars. Such transit signals are on the order of 100 ppm. The high photometric precision demanded by Kepler requires detailed knowledge of how the Kepler pixels respond to starlight during a nominal observation. This information is provided by the Kepler pixel response function (PRF), defined as the composite of Kepler's optical point-spread function, integrated spacecraft pointing jitter during a nominal cadence and other systematic effects. To provide sub-pixel resolution, the PRF is represented as a piecewise-continuous polynomial on a sub-pixel mesh. This continuous representation allows the prediction of a star's flux value on any pixel given the star's pixel position. The advantages and difficulties of this polynomial representation are discussed, including characterization of spatial variation in the PRF and the smoothing of discontinuities between sub-pixel polynomial patches. On-orbit super-resolution measurements of the PRF across the Kepler field of view are described. Two uses of the PRF are presented: the selection of pixels for each star that maximizes the photometric signal-to-noise ratio for that star, and PRF-fitted centroids which provide robust and accurate stellar positions on the CCD, primarily used for attitude and plate scale tracking. Good knowledge of the PRF has been a critical component for the successful collection of high-precision photometry by Kepler.

  3. Distribution fitting-based pixel labeling for histology image segmentation

    NASA Astrophysics Data System (ADS)

    He, Lei; Long, L. Rodney; Antani, Sameer; Thoma, George

    2011-03-01

    This paper presents a new pixel labeling algorithm for complex histology image segmentation. For each image pixel, a Gaussian mixture model is applied to estimate its neighborhood intensity distributions. With this local distribution fitting, a set of pixels having a full set of source classes (e.g. nuclei, stroma, connective tissue, and background) in their neighborhoods are identified as the seeds for pixel labeling. A seed pixel is labeled by measuring its intensity distance to each of its neighborhood distributions, and the one with the shortest distance is selected to label the seed. For non-seed pixels, we propose two different labeling schemes: global voting and local clustering. In global voting each seed classifies a non-seed pixel into one of the seed's local distributions, i.e., it casts one vote; the final label for the non-seed pixel is the class which gets the most votes, across all the seeds. In local clustering, each non-seed pixel is labeled by one of its own neighborhood distributions. Because the local distributions in a non-seed pixel neighborhood do not necessarily correspond to distinct source classes (i.e., two or more local distributions may be produced by the same source class), we first identify the "true" source class of each local distribution by using the source classes of the seed pixels and a minimum distance criterion to determine the closest source class. The pixel can then be labeled as belonging to this class. With both labeling schemes, experiments on a set of uterine cervix histology images show encouraging performance of our algorithm when compared with traditional multithresholding and K-means clustering, as well as state-of-the-art mean shift clustering, multiphase active contours, and Markov random field-based algorithms.

  4. The PixFEL project: development of advanced X-ray pixel detectors for application at future FEL facilities

    NASA Astrophysics Data System (ADS)

    Rizzo, G.; Comotti, D.; Fabris, L.; Grassi, M.; Lodola, L.; Malcovati, P.; Manghisoni, M.; Ratti, L.; Re, V.; Traversi, G.; Vacchi, C.; Batignani, G.; Bettarini, S.; Casarosa, G.; Forti, F.; Morsani, F.; Paladino, A.; Paoloni, E.; Dalla Betta, G.-F.; Pancheri, L.; Verzellesi, G.; Xu, H.; Mendicino, R.; Benkechkache, M. A.

    2015-02-01

    The PixFEL project aims to develop an advanced X-ray camera for imaging suited for the demanding requirements of next generation free electron laser (FEL) facilities. New technologies can be deployed to boost the performance of imaging detectors as well as future pixel devices for tracking. In the first phase of the PixFEL project, approved by the INFN, the focus will be on the development of the microelectronic building blocks, carried out with a 65 nm CMOS technology, implementing a low noise analog front-end channel with high dynamic range and compression features, a low power ADC and high density memory. At the same time PixFEL will investigate and implement some of the enabling technologies to assembly a seamless large area X-ray camera composed by a matrix of multilayer four-side buttable tiles. A pixel matrix with active edge will be developed to minimize the dead area of the sensor layer. Vertical interconnection of two CMOS tiers will be explored to build a four-side buttable readout chip with small pixel pitch and all the on-board required functionalities. The ambitious target requirements of the new pixel device are: single photon resolution, 1 to 104 photons @ 1 keV to 10 keV input dynamic range, 10-bit analog to digital conversion up to 5 MHz, 1 kevent in-pixel memory and 100 μm pixel pitch. The long term goal of PixFEL will be the development of a versatile X-ray camera to be operated either in burst mode (European XFEL), or in continuous mode to cope with the high frame rates foreseen for the upgrade phase of the LCLS-II at SLAC.

  5. The quartz hazard: effects of surface and matrix on inflammogenic activity.

    PubMed

    Donaldson, K; Stone, V; Duffin, R; Clouter, A; Schins, R; Borm, P

    2001-01-01

    Modification of the quartz surface during the history of the particle is a powerful idea in understanding the variability of the quartz hazard. Interactions between quartz and other minerals are likely to occur in sediments, during industrial processing, or in matrix-bound quartz. We discuss new evidence regarding the basis of changes in the quartz surface that relate to changes in its ability to cause inflammation. Different samples of quartz were subjected to various biological assays. Endpoints included instillation of quartz into the tracheobronchial tree and measurement of PMN numbers in bronchoalveolar lavage (BAL) and in lung tissue, levels of the chemokine MIP-2 in BAL, and nuclear translocation of the transcription factor NF-kappaB in BAL cells. In vitro biological assays included cytotoxicity to epithelial cells, hemolytic activity, and radical activity of the particle surface as measured by electron spin resonance. Treatment of quartz with aluminium lactate impaired its ability to cause PMN recruitment, chemokine release, and NF-kappaB nuclear translocation in BAL. Workplace quartzes had no proinflammatory activity, which correlated with their ability to cause hemolysis but not their electron spin resonance (ESR) activity. Quartz in a matrix with coalmine dust or fly-ash showed different effects. In fly-ash, the toxicity was masked, but coalmine dusts were more toxic to epithelial cells than pure quartz in vitro; however, after instillation, the long-term inflammation was not related to the in vitro activity. Amelioration of quartz surface activity can occur in workplace samples of quartz and quartz samples whose surface is protected, to the extent that they have very little inflammogenic activity and display an inability to activate key subcellular pathways that lead to inflammation. Quartz from a workplace whose surface has been affected, or in a matrix such as coalmine dust or fly-ash, can have its toxicity modulated. These effects are due to minerals

  6. Matrix metalloproteinase expression and activity in trophoblast-decidual tissues at organogenesis in CF-1 mouse.

    PubMed

    Fontana, Vanina; Coll, Tamara A; Sobarzo, Cristian M A; Tito, Leticia Perez; Calvo, Juan Carlos; Cebral, Elisa

    2012-10-01

    During early placentation, matrix metalloproteinases (MMPs) play important roles in decidualization, trophoblast migration, invasion, angiogenesis, vascularization and extracellular matrix (ECM) remodeling of the endometrium. The aim of our study was to analyze the localization, distribution and differential expression of MMP-2 and -9 in the organogenic implantation site and to evaluate in vivo and in vitro decidual MMP-2 and -9 activities on day 10 of gestation in CF-1 mouse. Whole extracts for Western blotting of organogenic E10-decidua expressed MMP-2 and -9 isoforms. MMP-2 immunoreactivity was found in a granular and discrete pattern in ECM of mesometrial decidua (MD) near maternal blood vessels and slightly in non-decidualized endometrium (NDE). Immunoexpression of MMP-9 was also detected in NDE, in cytoplasm of decidual cells and ECM of vascular MD, in trophoblastic area and in growing antimesometrial deciduum. Gelatin zymography showed that MMP-9 activity was significantly lower in CM compared to the active form of direct (not cultured) and cultured decidua. The decidual active MMP-9 was significantly higher than the active MMP-2. These results show differential localization, protein expression and enzymatic activation of MMPs, suggesting specific roles for MMP-2 and MMP-9 in decidual and trophoblast tissues related to organogenic ECM remodeling and vascularization during early establishment of mouse placentation. PMID:22714107

  7. Direct measurement of matrix metalloproteinase activity in 3D cellular microenvironments using a fluorogenic peptide substrate

    PubMed Central

    Leight, Jennifer L.; Alge, Daniel L.; Maier, Andrew J.; Anseth, Kristi S.

    2014-01-01

    Incorporation of degradable moieties into synthetic hydrogels has greatly increased the utility of these three-dimensional matrices for in vitro cell culture as well as tissue engineering applications. A common method for introducing degradability is the inclusion of oligopeptides sensitive to cleavage by matrix metalloproteinases (MMPs), enabling cell-mediated remodeling and migration within the material. While this strategy has been effective, characterization and measurement of cell-mediated degradation in these materials has remained challenging. There are 20+ MMP family members whose activity is regulated in space and time by a number of biochemical and biophysical cues. Thus, the typical approach of characterizing cleavage of degradable moieties in solution with recombinant enzymes does not easily translate to three dimensional cell-mediated matrix remodeling. To address this challenge, we report here the synthesis of a cell-laden hydrogel matrix functionalized with a fluorogenic peptide substrate to provide real-time, quantitative monitoring of global MMP activity. Using this system, stimulation of MMP activity was observed with growth factor treatment in mammary epithelial cells and compared to classical zymography results. Further, the effect of biophysical cues on MMP activity of human mesenchymal stem cells was also investigated where more rigid hydrogels were observed to increase MMP activity. The regulation of MMP activity by these biochemical and biophysical cues highlights the need for in situ, real time measurement of hydrogel degradation, and use of these functionalized hydrogels will aid in future rational design of degradable synthetic hydrogels for in vitro cell studies and tissue engineering applications. PMID:23830581

  8. Charge Resolution of the Silicon Matrix of the ATIC Experiment

    NASA Technical Reports Server (NTRS)

    Zatsepin, V. I.; Adams, J. H., Jr.; Ahn, H. S.; Bashindzhagyan, G. L.; Batkov, K. E.; Case, G.; Christl, M.; Ganel, O.; Fazely, A. R.; Ganel, O.; Six, N. Frank (Technical Monitor)

    2002-01-01

    ATIC (Advanced Thin Ionization Calorimeter) is a balloon borne experiment designed to measure the cosmic ray composition for elements from hydrogen to iron and their energy spectra from approx.50 GeV to near 100 TeV. It consists of a Si-matrix detector to determine the charge of a CRT particle, a scintillator hodoscope for tracking, carbon interaction targets and a fully active BGO calorimeter. ATIC had its first flight from McMurdo, Antarctica from 28/12/2000 to 13/01/2001. The ATIC flight collected approximately 25 million events. The silicon matrix of the ATIC spectrometer is designed to resolve individual elements from proton to iron. To provide this resolution careful calibration of each pixel of the silicon matrix is required. Firstly, for each electronic channel of the matrix the pedestal value was subtracted taking into account its drift during the flight. The muon calibration made before the flight was used then to convert electric signals (in ADC channel number) to energy deposits in each pixel. However, the preflight muon calibration was not accurate enough for the purpose, because of lack of statistics in each pixel. To improve charge resolution the correction was done for the position of Helium peak in each pixel during the flight . The other way to set electric signals in electronics channels of the Si-matrix to one scale was correction for electric channel gains accurately measured in laboratory. In these measurements it was found that small different nonlinearities for different channels are present in the region of charge Z > 20. The correction for these non-linearities was not done yet. In linear approximation the method provides practically the same resolution as muon calibration plus He-peak correction. For searching a pixel with the signal of primary particle an indication from the cascade in the calorimeter was used. For this purpose a trajectory was reconstructed using weight centers of energy deposits in BGO layers. The point of intersection

  9. PIXELS: Using field-based learning to investigate students' concepts of pixels and sense of scale

    NASA Astrophysics Data System (ADS)

    Pope, A.; Tinigin, L.; Petcovic, H. L.; Ormand, C. J.; LaDue, N.

    2015-12-01

    Empirical work over the past decade supports the notion that a high level of spatial thinking skill is critical to success in the geosciences. Spatial thinking incorporates a host of sub-skills such as mentally rotating an object, imagining the inside of a 3D object based on outside patterns, unfolding a landscape, and disembedding critical patterns from background noise. In this study, we focus on sense of scale, which refers to how an individual quantified space, and is thought to develop through kinesthetic experiences. Remote sensing data are increasingly being used for wide-reaching and high impact research. A sense of scale is critical to many areas of the geosciences, including understanding and interpreting remotely sensed imagery. In this exploratory study, students (N=17) attending the Juneau Icefield Research Program participated in a 3-hour exercise designed to study how a field-based activity might impact their sense of scale and their conceptions of pixels in remotely sensed imagery. Prior to the activity, students had an introductory remote sensing lecture and completed the Sense of Scale inventory. Students walked and/or skied the perimeter of several pixel types, including a 1 m square (representing a WorldView sensor's pixel), a 30 m square (a Landsat pixel) and a 500 m square (a MODIS pixel). The group took reflectance measurements using a field radiometer as they physically traced out the pixel. The exercise was repeated in two different areas, one with homogenous reflectance, and another with heterogeneous reflectance. After the exercise, students again completed the Sense of Scale instrument and a demographic survey. This presentation will share the effects and efficacy of the field-based intervention to teach remote sensing concepts and to investigate potential relationships between students' concepts of pixels and sense of scale.

  10. Activation of matrix metalloproteinase-2 and -9 by 2- and 4-hydroxyestradiol.

    PubMed

    Paquette, Benoit; Bisson, Martine; Therriault, Hélène; Lemay, Rosalie; Paré, Mélanie; Banville, Pascale; Cantin, André M

    2003-10-01

    Breast cancer patients frequently develop metastases. This process requires the degradation of extracellular matrix proteins which act as a barrier to tumour cell passage. These proteins can be degraded by proteases, mainly the matrix metalloproteinases (MMPs). MMP-2 and -9 which are frequently detected in breast cancer tissues. ProMMPs are released from cancer cells, and their activation is considered to be a crucial step in metastases development. In breast cancer, estrogen metabolism is altered favouring the accumulation of 2- and 4-hydroxyestradiol (2- and 4-OHE(2)). These estradiol metabolites can generate free radicals. Since reactive species are known activators of proMMPs, this study was designed to determine if the free radicals generated by 2- and 4-OHE(2) can activate proMMP-2 and -9. Activation of MMPs by hydroxyestradiol was determined by monitoring the cleavage of a fluorogenic peptide and by zymography analysis. Both estradiol metabolites activated the MMP-2 and -9. 4-OHE(2) was a more potent activator than 2-OHE(2), which reflects its higher capacity to generate free radicals. ProMMPs activation was mainly mediated through O(2)*-, although the free radical HO* also activated the proMMPs but to a lesser extent. ProMMPs activation was not observed with estrogens that cannot generate free radicals, i.e. estradiol, estrone, 2- and 4-methoxyestradiol, and 16alpha-hydroxyestrone. These results demonstrate that 2- and 4-OHE(2) at a concentration as low as 10(-8)M can activate the proMMP-2 and -9 and might play an important role in the invasion of breast cancer cells.

  11. Active compensation of wavefront aberrations by controllable heating of lens with electric film heater matrix.

    PubMed

    Chen, Hua; Hou, Lv; Zhou, Xinglin

    2016-08-20

    We present a new apparatus for active compensation of wavefront aberrations by controllable heating of a lens using a film heater matrix. The annular electric film heater matrix, comprising 24 individual heaters, is attached to the periphery of a lens. Utilizing the linear superposition, and wavefront change proportional to the heating energy properties induced by heating, a controllable wavefront can be defined by solving a linear function. The two properties of wavefront change of a lens have been confirmed through a specially designed experiment. The feasibility of the compensation method is validated by compensating the wavefront of a plate lens. The results show that the wavefront of the lens changes from 12.52 to 2.95 nm rms after compensation. With a more precise electric controlling board, better results could be achieved. PMID:27556982

  12. Synthesis of In-situ Aluminum Matrix Composite Using a New Activated Powder Injection Method

    NASA Astrophysics Data System (ADS)

    Maleki, A.; Meratian, M.; Niroumand, B.; Gupta, M.

    2008-12-01

    In the present study, in-situ Al matrix composites containing alumina particles were synthesized by a new method that involved injection of an activated powder mixture into the molten aluminum, which was subsequently squeeze cast to minimize its porosity. The activated powder mixture was prepared by milling of powders of commercially pure aluminum and zinc oxide for a predetermined time. Milling for 60 minutes led to optimum activation of the reactant powders. Such activation reduced the reaction temperature from above 1000 °C to about 640 °C. Microstructural characterization studies revealed the formation of submicron size alumina particles with near equiaxed morphology and good particle/matrix interface. The composite specimen synthesized using the activated powder injection (API) method exhibited higher hardness, greater yield and tensile strengths, and lower elongation when compared to the monolithic specimen of similar composition. This article places particular emphasis on explaining the uniqueness of the processing methodology used in this study for synthesis of in-situ Al/Al2O3 composites.

  13. The modulation of platelet adhesion and activation by chitosan through plasma and extracellular matrix proteins.

    PubMed

    Lord, Megan S; Cheng, Bill; McCarthy, Simon J; Jung, MoonSun; Whitelock, John M

    2011-10-01

    Chitosan has been shown to promote initial wound closure events to prevent blood loss. Platelet adhesion and activation are crucial early events in these processes after traumatic bleeding leading to thrombus formation. Platelet adhesion to chitosan was found to be enhanced in the presence of adsorbed plasma and extracellular matrix proteins and was found to be primarily mediated by α(IIb)β(3) integrins, while α(2)β(1) integrins were found to be involved in platelet adhesion to collagen and perlecan. Platelets were found to be activated by chitosan, as shown by an increase in the expression of α(IIb)β(3) integrins and P-selectin, while the extent of activation was modulated by the presence of proteins including perlecan and fibrinogen. Collagen-coated chitosan was found to activate platelets to the same extent as either chitosan or collagen alone. These data support the role of plasma and extracellular matrix proteins in promoting chitosan mediated platelet adhesion and activation supporting the hypothesis that chitosan promotes wound healing via these interactions.

  14. From Pixels to Planets

    NASA Technical Reports Server (NTRS)

    Brownston, Lee; Jenkins, Jon M.

    2015-01-01

    The Kepler Mission was launched in 2009 as NASAs first mission capable of finding Earth-size planets in the habitable zone of Sun-like stars. Its telescope consists of a 1.5-m primary mirror and a 0.95-m aperture. The 42 charge-coupled devices in its focal plane are read out every half hour, compressed, and then downlinked monthly. After four years, the second of four reaction wheels failed, ending the original mission. Back on earth, the Science Operations Center developed the Science Pipeline to analyze about 200,000 target stars in Keplers field of view, looking for evidence of periodic dimming suggesting that one or more planets had crossed the face of its host star. The Pipeline comprises several steps, from pixel-level calibration, through noise and artifact removal, to detection of transit-like signals and the construction of a suite of diagnostic tests to guard against false positives. The Kepler Science Pipeline consists of a pipeline infrastructure written in the Java programming language, which marshals data input to and output from MATLAB applications that are executed as external processes. The pipeline modules, which underwent continuous development and refinement even after data started arriving, employ several analytic techniques, many developed for the Kepler Project. Because of the large number of targets, the large amount of data per target and the complexity of the pipeline algorithms, the processing demands are daunting. Some pipeline modules require days to weeks to process all of their targets, even when run on NASA's 128-node Pleiades supercomputer. The software developers are still seeking ways to increase the throughput. To date, the Kepler project has discovered more than 4000 planetary candidates, of which more than 1000 have been independently confirmed or validated to be exoplanets. Funding for this mission is provided by NASAs Science Mission Directorate.

  15. Novel integrated CMOS pixel structures for vertex detectors

    SciTech Connect

    Kleinfelder, Stuart; Bieser, Fred; Chen, Yandong; Gareus, Robin; Matis, Howard S.; Oldenburg, Markus; Retiere, Fabrice; Ritter, Hans Georg; Wieman, Howard H.; Yamamoto, Eugene

    2003-10-29

    Novel CMOS active pixel structures for vertex detector applications have been designed and tested. The overriding goal of this work is to increase the signal to noise ratio of the sensors and readout circuits. A large-area native epitaxial silicon photogate was designed with the aim of increasing the charge collected per struck pixel and to reduce charge diffusion to neighboring pixels. The photogate then transfers the charge to a low capacitance readout node to maintain a high charge to voltage conversion gain. Two techniques for noise reduction are also presented. The first is a per-pixel kT/C noise reduction circuit that produces results similar to traditional correlated double sampling (CDS). It has the advantage of requiring only one read, as compared to two for CDS, and no external storage or subtraction is needed. The technique reduced input-referred temporal noise by a factor of 2.5, to 12.8 e{sup -}. Finally, a column-level active reset technique is explored that suppresses kT/C noise during pixel reset. In tests, noise was reduced by a factor of 7.6 times, to an estimated 5.1 e{sup -} input-referred noise. The technique also dramatically reduces fixed pattern (pedestal) noise, by up to a factor of 21 in our tests. The latter feature may possibly reduce pixel-by-pixel pedestal differences to levels low enough to permit sparse data scan without per-pixel offset corrections.

  16. Aging enhances a mechanically-induced reduction in tendon strength by an active process involving matrix metalloproteinase activity.

    PubMed

    Dudhia, Jayesh; Scott, Charlotte M; Draper, Edward R C; Heinegård, Dick; Pitsillides, Andrew A; Smith, Roger K

    2007-08-01

    Age-associated and degenerative loss of functional integrity in soft tissues develops from effects of cumulative and subtle changes in their extracellular matrix (ECM). The highly ordered tendon ECM provides the tissue with its tensile strength during loading. As age and exercise collide in the high incidence of tendinopathies, we hypothesized that aged tendons fail due to cumulative damage resulting from a combination of diminished matrix repair and fragmentation of ECM proteins induced by prolonged cyclical loading, and that this is an active cell-mediated process. We developed an equine tendon explant model to examine the effect of age on the influence of prolonged cyclical loading at physiologically relevant strain rates (5% strain, 1 Hz for 24 h) on tissue mechanical properties, loss of ECM protein and matrix metalloproteinase (MMP) expression. We show significantly diminished mechanical strength of cyclically loaded tissue compared to controls (39.7 +/- 12%, P activity. Furthermore, tendon from older specimens was more susceptible to weakening (11-30 years, 50%P matrix protein, an integral ECM protein, an effect that could be mimicked by culture with fibronectin fragments. These findings indicate prolonged cyclical loading of physiological magnitude decreases tendon tensile strength by an active process, and that MMPs may contribute to loss of functional competence, exaggerated by age, via load-induced proteolytic disruption of the ECM.

  17. Distribution and activity levels of matrix metalloproteinase 2 and 9 in canine and feline osteosarcoma.

    PubMed

    Gebhard, Christiane; Fuchs-Baumgartinger, Andrea; Razzazi-Fazeli, Ebrahim; Miller, Ingrid; Walter, Ingrid

    2016-01-01

    Overexpression of matrix metalloproteinases (MMPs) has been associated with increased tumor aggressiveness and metastasis dissemination. We investigated whether the contrasting metastatic behavior of feline and canine osteosarcoma is related to levels and activities of MMP2 and MMP9. Zymography and immunohistochemistry were used to determine expression levels of MMP2 and MMP9 in canine and feline osteosarcoma. Using immunohistochemistry, increased MMP9 levels were identified in most canine osteosarcomas, whereas cat samples more often displayed moderate levels. High levels of pro-MMP9, pro-MMP2, and active MMP2 were detected by gelatin zymography in both species, with significantly higher values for active MMP2 in canine osteosarcoma. These findings indicate that MMP2 is probably involved in canine and feline osteosarcoma and their expression and activity could be associated with the different metastatic behavior of canine and feline osteosarcoma. PMID:26733734

  18. The parasite Entamoeba histolytica exploits the activities of human matrix metalloproteinases to invade colonic tissue.

    PubMed

    Thibeaux, Roman; Avé, Patrick; Bernier, Michèle; Morcelet, Marie; Frileux, Pascal; Guillén, Nancy; Labruyère, Elisabeth

    2014-10-07

    Intestinal invasion by the protozoan parasite Entamoeba histolytica is characterized by remodelling of the extracellular matrix (ECM). The parasite cysteine proteinase A5 (CP-A5) is thought to cooperate with human matrix metalloproteinases (MMPs) involved in ECM degradation. Here, we investigate the role CP-A5 plays in the regulation of MMPs upon mucosal invasion. We use human colon explants to determine whether CP-A5 activates human MMPs. Inhibition of the MMPs' proteolytic activities abolishes remodelling of the fibrillar collagen structure and prevents trophozoite invasion of the mucosa. In the presence of trophozoites, MMPs-1 and -3 are overexpressed and are associated with fibrillar collagen remodelling. In vitro, CP-A5 performs the catalytic cleavage needed to activate pro-MMP-3, which in turn activates pro-MMP-1. Ex vivo, incubation with recombinant CP-A5 was enough to rescue CP-A5-defective trophozoites. Our results suggest that MMP-3 and/or CP-A5 inhibitors may be of value in further studies aiming to treat intestinal amoebiasis.

  19. A novel CMOS sensor with in-pixel auto-zeroed discrimination for charged particle tracking

    NASA Astrophysics Data System (ADS)

    Degerli, Y.; Guilloux, F.; Orsini, F.

    2014-05-01

    With the aim of developing fast and granular Monolithic Active Pixels Sensors (MAPS) as new charged particle tracking detectors for high energy physics experiments, a new rolling shutter binary pixel architecture concept (RSBPix) with in-pixel correlated double sampling, amplification and discrimination is presented. The discriminator features auto-zeroing in order to compensate process-related transistor mismatches. In order to validate the pixel, a first monolithic CMOS sensor prototype, including a pixel array of 96 × 64 pixels, has been designed and fabricated in the Tower-Jazz 0.18 μm CMOS Image Sensor (CIS) process. Results of laboratory tests are presented.

  20. Indirect flat-panel detector with avalanche gain: Fundamental feasibility investigation for SHARP-AMFPI (scintillator HARP active matrix flat panel imager)

    SciTech Connect

    Zhao Wei; Li Dan; Reznik, Alla; Lui, B.J.M.; Hunt, D.C.; Rowlands, J.A.; Ohkawa, Yuji; Tanioka, Kenkichi

    2005-09-15

    An indirect flat-panel imager (FPI) with avalanche gain is being investigated for low-dose x-ray imaging. It is made by optically coupling a structured x-ray scintillator CsI(Tl) to an amorphous selenium (a-Se) avalanche photoconductor called HARP (high-gain avalanche rushing photoconductor). The final electronic image is read out using an active matrix array of thin film transistors (TFT). We call the proposed detector SHARP-AMFPI (scintillator HARP active matrix flat panel imager). The advantage of the SHARP-AMFPI is its programmable gain, which can be turned on during low dose fluoroscopy to overcome electronic noise, and turned off during high dose radiography to avoid pixel saturation. The purpose of this paper is to investigate the important design considerations for SHARP-AMFPI such as avalanche gain, which depends on both the thickness d{sub Se} and the applied electric field E{sub Se} of the HARP layer. To determine the optimal design parameter and operational conditions for HARP, we measured the E{sub Se} dependence of both avalanche gain and optical quantum efficiency of an 8 {mu}m HARP layer. The results were used in a physical model of HARP as well as a linear cascaded model of the FPI to determine the following x-ray imaging properties in both the avalanche and nonavalanche modes as a function of E{sub Se}: (1) total gain (which is the product of avalanche gain and optical quantum efficiency); (2) linearity; (3) dynamic range; (4) gain nonuniformity resulting from thickness nonuniformity; and (5) effects of direct x-ray interaction in HARP. Our results showed that a HARP layer thickness of 8 {mu}m can provide adequate avalanche gain and sufficient dynamic range for x-ray imaging applications to permit quantum limited operation over the range of exposures needed for radiography and fluoroscopy.

  1. Lung Matrix Metalloproteinase Activation following Partial Hepatic Ischemia/Reperfusion Injury in Rats

    PubMed Central

    Ferrigno, Andrea; Rizzo, Vittoria; Tarantola, Eleonora

    2014-01-01

    Purpose. Warm hepatic ischemia-reperfusion (I/R) injury can lead to multiorgan dysfunction. The aim of the present study was to investigate whether acute liver I/R does affect the function and/or structure of remote organs such as lung, kidney, and heart via modulation of extracellular matrix remodelling. Methods. Male Sprague-Dawley rats were subjected to 30 min partial hepatic ischemia by clamping the hepatic artery and the portal vein. After a 60 min reperfusion, liver, lung, kidney, and heart biopsies and blood samples were collected. Serum hepatic enzymes, creatinine, urea, Troponin I and TNF-alpha, and tissue matrix metalloproteinases (MMP-2, MMP-9), myeloperoxidase (MPO), malondialdehyde (MDA), and morphology were monitored. Results. Serum levels of hepatic enzymes and TNF-alpha were concomitantly increased during hepatic I/R. An increase in hepatic MMP-2 and MMP-9 activities was substantiated by tissue morphology alterations. Notably, acute hepatic I/R affect the lung inasmuch as MMP-9 activity and MPO levels were increased. No difference in MMPs and MPO was observed in kidney and heart. Conclusions. Although the underlying mechanism needs further investigation, this is the first study in which the MMP activation in a distant organ is reported; this event is probably TNF-alpha-mediated and the lung appears as the first remote organ to be involved in hepatic I/R injury. PMID:24592193

  2. Phloroglucinol Reduces Photodamage in Hairless Mice via Matrix Metalloproteinase Activity Through MAPK Pathway.

    PubMed

    Im, A-Rang; Nam, Kung-Woo; Hyun, Jin Won; Chae, Sungwook

    2016-01-01

    We investigated the photoprotective activity of phloroglucinol on ultraviolet B (UVB)-induced deleterious effects in hairless mice in vivo. To assess the photoprotective effect of phloroglucinol, phloroglucinol-treated HR-1 hairless male mice were exposed to UVB irradiation. The inhibitory activity of phloroglucinol on wrinkle formation was determined by analysis of skin replicas, epidermal thickness based on histological examination and collagen damage. Matrix metalloproteinase-1 (MMP-1), matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase (TIMP) mRNA levels were measured by real-time PCR. UVB induced transcription of proinflammatory cytokines, including interleukin-1 beta (IL-1β, IL-6) and IL-8 (IL-8). The protective effects of phloroglucinol on UVB-induced skin photoaging were examined by measuring protein levels of MMPs and mitogen-activated protein (MAP) kinases. The results of these experiments suggest that phloroglucinol has a significant beneficial effect on the barrier function of the skin. In hairless mice, signs of photoaging and photodamage, including coarse wrinkle formation, epidermal thickness and elastic fiber degeneration, were reduced in severity by phloroglucinol application. The phloroglucinol-treated group showed remarkably decreased mRNA levels of MMP-1, MMP-9 and inflammatory cytokines in comparison with those of the UVB-induced group. Oral administration of phloroglucinol attenuated phosphorylation of MAP kinases, including extracellular signal-regulated kinase, c-Jun N-terminal kinase and p38. PMID:26537624

  3. CMS Pixel Data Quality Monitoring

    NASA Astrophysics Data System (ADS)

    Merkel, Petra

    2010-05-01

    We present the CMS Pixel Data Quality Monitoring (DQM) system. The concept and architecture are discussed. The monitored quantities are introduced, and the methods on how to ensure that the detector takes high-quality data with large efficiency are explained. Finally we describe the automated data certification scheme, which is used to certify and classify the data from the Pixel detector for physics analyses.

  4. Hybrid Pixel Detectors for gamma/X-ray imaging

    NASA Astrophysics Data System (ADS)

    Hatzistratis, D.; Theodoratos, G.; Zografos, V.; Kazas, I.; Loukas, D.; Lambropoulos, C. P.

    2015-09-01

    Hybrid pixel detectors are made by direct converting high-Z semi-insulating single crystalline material coupled to complementary-metal-oxide semiconductor (CMOS) readout electronics. They are attractive because direct conversion exterminates all the problems of spatial localization related to light diffusion, energy resolution, is far superior from the combination of scintillation crystals and photomultipliers and lithography can be used to pattern electrodes with very fine pitch. We are developing 2-D pixel CMOS ASICs, connect them to pixilated CdTe crystals with the flip chip and bump bonding method and characterize the hybrids. We have designed a series of circuits, whose latest member consists of a 50×25 pixel array with 400um pitch and an embedded controller. In every pixel a full spectroscopic channel with time tagging information has been implemented. The detectors are targeting Compton scatter imaging and they can be used for coded aperture imaging too. Hybridization using CMOS can overcome the limit put on pixel circuit complexity by the use of thin film transistors (TFT) in large flat panels. Hybrid active pixel sensors are used in dental imaging and other applications (e.g. industrial CT etc.). Thus X-ray imaging can benefit from the work done on dynamic range enhancement methods developed initially for visible and infrared CMOS pixel sensors. A 2-D CMOS ASIC with 100um pixel pitch to demonstrate the feasibility of such methods in the context of X-ray imaging has been designed.

  5. High frame rate measurements of semiconductor pixel detector readout IC

    NASA Astrophysics Data System (ADS)

    Szczygiel, R.; Grybos, P.; Maj, P.

    2012-07-01

    We report on high count rate and high frame rate measurements of a prototype IC named FPDR90, designed for readouts of hybrid pixel semiconductor detectors used for X-ray imaging applications. The FPDR90 is constructed in 90 nm CMOS technology and has dimensions of 4 mm×4 mm. Its main part is a matrix of 40×32 pixels with 100 μm×100 μm pixel size. The chip works in the single photon counting mode with two discriminators and two 16-bit ripple counters per pixel. The count rate per pixel depends on the effective CSA feedback resistance and can be set up to 6 Mcps. The FPDR90 can operate in the continuous readout mode, with zero dead time. Due to the architecture of digital blocks in pixel, one can select the number of bits read out from each counter from 1 to 16. Because in the FPDR90 prototype only one data output is available, the frame rate is 9 kfps and 72 kfps for 16 bits and 1 bit readout, respectively (with nominal clock frequency of 200 MHz).

  6. Stimulation of Periodontal Ligament Stem Cells by Dentin Matrix Protein 1 Activates Mitogen-Activated Protein Kinase and Osteoblast Differentiation

    PubMed Central

    Chandrasekaran, Sangeetha; Ramachandran, Amsaveni; Eapen, Asha; George, Anne

    2013-01-01

    Background Periodontitis can ultimately result in tooth loss. Many natural and synthetic materials have been tried to achieve periodontal regeneration, but the results remain variable and unpredictable. We hypothesized that exogenous treatment with dentin matrix protein 1 (DMP1) activates specific genes and results in phenotypic and functional changes in human periodontal ligament stem cells (hPDLSCs). Methods hPDLSCs were isolated from extracted teeth and cultured in the presence or absence of DMP1. Quantitative polymerase chain reactions were performed to analyze the expression of several genes involved in periodontal regeneration. hPDLSCs were also processed for immunocytochemical and Western blot analysis using phosphorylated extracellular signal-regulated kinase (pERK) and ERK antibodies. Alkaline phosphatase and von Kossa staining were performed to characterize the differentiation of hPDLSCs into osteoblasts. Field emission scanning electron microscopic analysis of the treated and control cell cultures were also performed. Results Treatment with DMP1 resulted in the upregulation of genes, such as matrix metalloproteinase-2, alkaline phosphatase, and transforming growth factor β1. Activation of ERK mitogen-activated protein kinase signaling pathway and translocation of pERK from the cytoplasm to the nucleus was observed. Overall, DMP1-treated cells showed increased expression of alkaline phosphatase, increased matrix, and mineralized nodule formation when compared with untreated controls. Conclusion DMP1 can orchestrate a coordinated expression of genes and phenotypic changes in hPDLSCs by activation of the ERK signaling pathway, which may provide a valuable strategy for tissue engineering approaches in periodontal regeneration. PMID:22612367

  7. Matrix metalloproteinase and elastase activities in LPS-induced acute lung injury in guinea pigs.

    PubMed

    D'Ortho, M P; Jarreau, P H; Delacourt, C; Macquin-Mavier, I; Levame, M; Pezet, S; Harf, A; Lafuma, C

    1994-03-01

    Matrix metalloproteinases (MMPs) and elastase are proteolytic enzymes specifically directed against extracellular matrix (ECM) components. They are secreted by inflammatory cells and may consequently contribute to the lesions of the ECM observed during acute pulmonary edema. We therefore evaluated the MMP and elastase activities, which are secreted by cultured alveolar macrophages (AMACs) and polymorphonuclear neutrophils (PMNs) and present in the bronchoalveolar lavage (BAL) fluid in a guinea pig model of acute lung injury induced by intratracheal instillation of lipopolysaccharide (LPS). The control group was given 0.9% NaCl. 24 h after instillation, a BAL was performed, the BAL fluid was separated from the cells by centrifugation, and AMACs and PMNs were separately cultured for 24 h. In BAL fluid from LPS-treated guinea pigs, we found 1) an increase in free gelatinase activity, tested on [3H]gelatin (0.7 +/- 0.2 micrograms.200 microliters BAL fluid-1.48 h-1 vs. 0.2 +/- 0.1 in controls, P < 0.05), and 2) increased total gelatinase activities, as assessed by zymography. The molecular masses of the major gelatinase species found in BAL fluid by zymography were 92 and 68 kDa. The 92-kDa gelatinase was secreted by both AMACs and PMNs, as demonstrated by zymography of their respective culture media. When tested on [3H]elastin, the elastase activity of BAL fluid of LPS-treated animals exhibited no increase, but when tested on a synthetic peptidic substrate [N-succinyl-(L-alanine)3-p-nitro anilide (SLAPN)], increased elastase-like activity was observed (from 17 +/- 4 nmol of SLAPN.200 microliters BAL fluid-1.24 h-1 in control group to 34 +/- 8 in LPS group, P < 0.05). This increase was attributable to the activity of a metalloendopeptidase that was inhibited by the metal chelator EDTA but not by the specific tissue inhibitor of MMPs.

  8. Matrix metalloproteinase expression and activity following prostaglandin F(2 alpha)-induced luteolysis.

    PubMed

    Ricke, William A; Smith, George W; Smith, Michael F

    2002-03-01

    Luteal tissue contains matrix metalloproteinases (MMPs) that cleave specific components of the extracellular matrix (ECM) and are inhibited by tissue inhibitors of metalloproteinases (TIMPs). We previously reported a decrease in luteal TIMP-1 within 15 min of prostaglandin F(2 alpha) (PGF(2 alpha))-induced luteolysis. An increase in the MMP:TIMP ratio may promote ECM degradation and apoptosis, as observed in other tissues that undergo involution. The objectives of these experiments were to determine whether 1) PGF(2 alpha) affects expression of mRNA encoding fibrillar collagenases (MMP-1 and -13), gelatinases A and B (MMP-2 and -9), membrane type (mt)-1 MMP (MMP-14), stromelysin (MMP-3), and matrilysin (MMP-7), and 2) PGF(2 alpha) increases MMP activity during PGF(2 alpha)-induced luteolysis in sheep. Corpora lutea (n = 3-10/time point) were collected at 0, 15, and 30 min and 1, 2, 4, 6, 12, 24, and 48 h after PGF(2 alpha) administration. Northern blot analysis confirmed the presence of all MMPs except MMP-9. Expression of mRNA for the above MMPs (except MMP-2) increased significantly (P < 0.05) by 30 min, and all MMPs increased significantly (P < 0.05) by 6 h after PGF(2 alpha) administration. Expression of MMP-14 mRNA increased significantly (P < 0.05) by 15 min post-PGF(2 alpha) and remained elevated through 48 h. MMP activity in luteal homogenates (following proenzyme activation and inactivation of inhibitors) was increased significantly (P < 0.05) by 15 min and remained elevated through 48 h post-PGF(2 alpha). MMP activity was localized (in situ zymography) to the pericellular area of various cell types in the 0-h group and was markedly increased by 30 min post-PGF(2 alpha). MMP mRNA expression and activity were significantly increased following PGF(2 alpha) treatment. Increased MMP activity may promote ECM degradation during luteolysis.

  9. Local Pixel Bundles: Bringing the Pixels to the People

    NASA Astrophysics Data System (ADS)

    Anderson, Jay

    2014-12-01

    The automated galaxy-based alignment software package developed for the Frontier Fields program (hst2galign, see Anderson & Ogaz 2014 and http://www.stsci.edu/hst/campaigns/frontier-fields/) produces a direct mapping from the pixels of the flt frame of each science exposure into a common master frame. We can use these mappings to extract the flt-pixels in the vicinity of a source of interest and package them into a convenient "bundle". In addition to the pixels, this data bundle can also contain "meta" information that will allow users to transform positions from the flt pixels to the reference frame and vice-versa. Since the un-resampled pixels in the flt frames are the only true constraints we have on the astronomical scene, the ability to inter-relate these pixels will enable many high-precision studies, such as: point-source-fitting and deconvolution with accurate PSFs, easy exploration of different image-combining algorithms, and accurate faint-source finding and photometry. The data products introduced in this ISR are a very early attempt to provide the flt-level pixel constraints in a package that is accessible to more than the handful of experts in HST astrometry. The hope is that users in the community might begin using them and will provide feedback as to what information they might want to see in the bundles and what general analysis packages they might find useful. For that reason, this document is somewhat informally written, since I know that it will be modified and updated as the products and tools are optimized.

  10. Collagen-binding VEGF mimetic peptide: Structure, matrix interaction, and endothelial cell activation

    NASA Astrophysics Data System (ADS)

    Chan, Tania R.

    Long term survival of artificial tissue constructs depends greatly on proper vascularization. In nature, differentiation of endothelial cells and formation of vasculature are directed by dynamic spatio-temporal cues in the extracellular matrix that are difficult to reproduce in vitro. In this dissertation, we present a novel bifunctional peptide that mimics matrix-bound vascular endothelial growth factor (VEGF), which can be used to encode spatially controlled angiogenic signals in collagen-based scaffolds. The peptide, QKCMP, contains a collagen mimetic domain (CMP) that binds to type I collagen by a unique triple helix hybridization mechanism and a VEGF mimetic domain (QK) with pro-angiogenic activity. We demonstrate QKCMP's ability to hybridize with native and heat denatured collagens through a series of binding studies on collagen and gelatin substrates. Circular dichroism experiments show that the peptide retains the triple helical structure vital for collagen binding, and surface plasmon resonance study confirms the molecular interaction between the peptide and collagen strands. Cell culture studies demonstrate QKCMP's ability to induce endothelial cell morphogenesis and network formation as a matrix-bound factor in 2D and 3D collagen scaffolds. We also show that the peptide can be used to spatially modify collagen-based substrates to promote localized endothelial cell activation and network formation. To probe the biological events that govern these angiogenic cellular responses, we investigated the cell signaling pathways activated by collagen-bound QKCMP and determined short and long-term endothelial cell response profiles for p38, ERK1/2, and Akt signal transduction cascades. Finally, we present our efforts to translate the peptide's in vitro bioactivity to an in vivo burn injury animal model. When implanted at the wound site, QKCMP functionalized biodegradable hydrogels induce enhanced neovascularization in the granulation tissue. The results show QKCMP

  11. THE DIFFERENTIAL REGULATION OF CELL MOTILE ACTIVITY THROUGH MATRIX STIFFNESS AND POROSITY IN THREE DIMENSIONAL COLLAGEN MATRICES

    PubMed Central

    Miron-Mendoza, Miguel; Seemann, Joachim; Grinnell, Frederick

    2010-01-01

    In three dimensional collagen matrices, cell motile activity results in collagen translocation, cell spreading and cell migration. Cells can penetrate into the matrix as well as spread and migrate along its surface. In the current studies, we quantitatively characterize collagen translocation, cell spreading and cell migration in relationship to collagen matrix stiffness and porosity. Collagen matrices prepared with 1 to 4 mg/ml collagen exhibited matrix stiffness (storage modulus measured by oscillating rheometry) increasing from 4 to 60 Pa and matrix porosity (measured by scanning electron microscopy) decreasing from 4 to 1 μm2. Over this collagen concentration range, the consequences of cell motile activity changed markedly. As collagen concentration increased, cells no longer were able to cause translocation of collagen fibrils. Cell migration increased and cell spreading changed from dendritic to more flattened and polarized morphology depending on location of cells within or on the surface of the matrix. Collagen translocation appeared to depend primarily on matrix stiffness, whereas cell spreading and migration were less dependent on matrix stiffness and more dependent on collagen matrix porosity. PMID:20537378

  12. Chromium liquid waste inertization in an inorganic alkali activated matrix: leaching and NMR multinuclear approach.

    PubMed

    Ponzoni, Chiara; Lancellotti, Isabella; Barbieri, Luisa; Spinella, Alberto; Saladino, Maria Luisa; Martino, Delia Chillura; Caponetti, Eugenio; Armetta, Francesco; Leonelli, Cristina

    2015-04-01

    A class of inorganic binders, also known as geopolymers, can be obtained by alkali activation of aluminosilicate powders at room temperature. The process is affected by many parameters (curing time, curing temperature, relative humidity etc.) and leads to a resistant matrix usable for inertization of hazardous waste. In this study an industrial liquid waste containing a high amount of chromium (≈ 2.3 wt%) in the form of metalorganic salts is inertized into a metakaolin based geopolymer matrix. One of the innovative aspects is the exploitation of the water contained in the waste for the geopolymerization process. This avoided any drying treatment, a common step in the management of liquid hazardous waste. The evolution of the process--from the precursor dissolution to the final geopolymer matrix hardening--of different geopolymers containing a waste amount ranging from 3 to 20%wt and their capability to inertize chromium cations were studied by: i) the leaching tests, according to the EN 12,457 regulation, at different curing times (15, 28, 90 and 540 days) monitoring releases of chromium ions (Cr(III) and Cr(VI)) and the cations constituting the aluminosilicate matrix (Na, Si, Al); ii) the humidity variation for different curing times (15 and 540 days); iii) SEM characterization at different curing times (28 and 540 days); iv) the trend of the solution conductivity and pH during the leaching test; v) the characterization of the short-range ordering in terms of TOT bonds (where T is Al or Si) by (29)Si and (27)Al solid state magic-angle spinning nuclear magnetic resonance (ss MAS NMR) for geopolymers containing high amounts of waste (10-20%wt). The results show the formation of a stable matrix after only 15 days independently on the waste amount introduced; the longer curing times increase the matrices stabilities and their ability to immobilize chromium cations. The maximum amount of waste that can be inertized is around 10 wt% after a curing time of 28 days.

  13. Plasma Membrane Factor XIIIA Transglutaminase Activity Regulates Osteoblast Matrix Secretion and Deposition by Affecting Microtubule Dynamics

    PubMed Central

    Al-Jallad, Hadil F.; Myneni, Vamsee D.; Piercy-Kotb, Sarah A.; Chabot, Nicolas; Mulani, Amina; Keillor, Jeffrey W.; Kaartinen, Mari T.

    2011-01-01

    Transglutaminase activity, arising potentially from transglutaminase 2 (TG2) and Factor XIIIA (FXIIIA), has been linked to osteoblast differentiation where it is required for type I collagen and fibronectin matrix deposition. In this study we have used an irreversible TG-inhibitor to ‘block –and-track’ enzyme(s) targeted during osteoblast differentiation. We show that the irreversible TG-inhibitor is highly potent in inhibiting osteoblast differentiation and mineralization and reduces secretion of both fibronectin and type I collagen and their release from the cell surface. Tracking of the dansyl probe by Western blotting and immunofluorescence microscopy demonstrated that the inhibitor targets plasma membrane-associated FXIIIA. TG2 appears not to contribute to crosslinking activity on the osteoblast surface. Inhibition of FXIIIA with NC9 resulted in defective secretory vesicle delivery to the plasma membrane which was attributable to a disorganized microtubule network and decreased microtubule association with the plasma membrane. NC9 inhibition of FXIIIA resulted in destabilization of microtubules as assessed by cellular Glu-tubulin levels. Furthermore, NC9 blocked modification of Glu-tubulin into 150 kDa high-molecular weight Glu-tubulin form which was specifically localized to the plasma membrane. FXIIIA enzyme and its crosslinking activity were colocalized with plasma membrane-associated tubulin, and thus, it appears that FXIIIA crosslinking activity is directed towards stabilizing the interaction of microtubules with the plasma membrane. Our work provides the first mechanistic cues as to how transglutaminase activity could affect protein secretion and matrix deposition in osteoblasts and suggests a novel function for plasma membrane FXIIIA in microtubule dynamics. PMID:21283799

  14. Method to evaluate the proliferation of activated lymphocytes in a three-dimensional collagen matrix.

    PubMed

    Davidova, Natalya V; Gorlina, Natalia K; Sharova, Svetlana V; Cheredeev, Anatoly N; Kozlov, Ivan G

    2002-12-01

    It is well known that the enhancement of the cell-matrix interactions represents one of the early steps in the process of lymphocyte activation. However, the information regarding the role of these interactions in the late stages of lymphocyte activation (in particular, the proliferation) is still controversial. This is basically due to the absence of adequate experimental models. In the present work we carried out a step-by-step modification of a well-studied model of mitogen-stimulated lymphocyte activation, adjusting it to the conditions of a three-dimensional collagen matrix (3D-CM). All the changes added to the standard procedure in the process of this modification were rigorously controlled using various experimental models. The final version of the method includes the following steps: (i) 24-h lymphocyte (lymphocyte fraction from mouse spleen) preincubation with mitogens (Con A or LPS) with a subsequent cell wash (parameters being controlled: irreversible lymphocyte activation, independence of the proliferation from cell-cell interactions); (ii) transfer of the activated lymphocytes to (3)H-thymidine containing 3D-CM and incubation for 48 h (controlled parameters: distribution of the radioactive label within the 3D-CM and its biological accessibility to lymphocytes); (iii) degradation of the 3D-CM with bacterial collagenase and cell transfer onto glass fiber filters (controlled parameters: cell viability after cultivation in the 3D-CM and treatment with the collagenase). With this method we found that the proliferation of the Con A- and LPS-stimulated lymphocytes in 3D-CM was dramatically inhibited (by 66.5 +/- 14.9% and by 88.1 +/- 10.2%, respectively). The discovered inhibition of the lymphocyte proliferation was not a consequence of either the ineffectiveness of the mitogens, the disruption of the cell-cell interactions, an insufficient inclusion of the radioactive label into cells, or of a decreased cell viability.

  15. Aryl hydrocarbon receptor activation impairs extracellular matrix remodeling during zebra fish fin regeneration.

    PubMed

    Andreasen, Eric A; Mathew, Lijoy K; Löhr, Christiane V; Hasson, Rachelle; Tanguay, Robert L

    2007-01-01

    Adult zebra fish completely regenerate their caudal (tail) fin following partial amputation. Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) inhibits this regenerative process. Proper regulation of transcription, innervation, vascularization, and extracellular matrix (ECM) composition is essential for complete fin regeneration. Previous microarray studies suggest that genes involved in ECM regulation are misexpressed following activation of the aryl hydrocarbon receptor. To investigate whether TCDD blocks regeneration by impairing ECM remodeling, male zebra fish were i.p. injected with 50 ng/g TCDD or vehicle, and caudal fins were amputated. By 3 days postamputation (dpa), the vascular network in the regenerating fin of TCDD-exposed fish was disorganized compared to vehicle-exposed animals. Furthermore, immunohistochemical staining revealed that axonal outgrowth was impacted by TCDD as early as 3 dpa. Histological analysis demonstrated that TCDD exposure leads to an accumulation of collagen at the end of the fin ray just distal to the amputation site by 3 dpa. Mature lepidotrichial-forming cells (fin ray-forming cells) were not observed in the fins of TCDD-treated fish. The capacity to metabolize ECM was also altered by TCDD exposure. Quantitative real-time PCR studies revealed that the aryl hydrocarbon pathway is active and that matrix-remodeling genes are expressed in the regenerate following TCDD exposure.

  16. Gelatinase activity of matrix metalloproteinases in the cerebrospinal fluid of various patient populations.

    PubMed

    Valenzuela, M A; Cartier, L; Collados, L; Kettlun, A M; Araya, F; Concha, C; Flores, L; Wolf, M E; Mosnaim, A D

    1999-01-01

    We have studied the enzymatic gelatinolytic activity of matrix metalloproteinases (MMPs) present in cerebrospinal fluid (CSF) of samples obtained from 67 individuals, twenty-one nonneurological patients (considered controls) and 46 subjects with various neurological disorders e.g., vascular lesions, demyelination, inflammatory, degenerative and prion diseases. Biochemical characterization of MMPs, a family of neutral proteolytic enzymes involved in extracellular matrix modeling, included determination of substrate specificity and Ca+2 dependency, as well as the effects of protease inactivators, carboxylic and His (histidine) residue modifiers, and antibiotics. Whereas all CSF samples expressed MMP-2 (gelatinase A) activity, it corresponded in most cases (normal and pathological samples) to its latent form (proenzyme; pMMP-2). In general, inflammatory neurological diseases (especially meningitis and neurocisticercosis) were associated with the presence of a second enzyme, MMP-9 (or gelatinase B). Whereas MMP-9 was found in the CSF of every tropical spastic paraparesis patient studied, its presence in samples from individuals with vascular lesions was uncommon. Patients blood-brain barrier damage was ascertained by determining total CSF protein content using both, the conventional polyacrylamide gel electrophoresis procedure under denaturing conditions and capillary zone electrophoresis.

  17. Design of a 3D-IC multi-resolution digital pixel sensor

    NASA Astrophysics Data System (ADS)

    Brochard, N.; Nebhen, J.; Dubois, J.; Ginhac, D.

    2016-04-01

    This paper presents a digital pixel sensor (DPS) integrating a sigma-delta analog-to-digital converter (ADC) at pixel level. The digital pixel includes a photodiode, a delta-sigma modulation and a digital decimation filter. It features adaptive dynamic range and multiple resolutions (up to 10-bit) with a high linearity. A specific row decoder and column decoder are also designed to permit to read a specific pixel chosen in the matrix and its neighborhood of 4 x 4. Finally, a complete design with the CMOS 130 nm 3D-IC FaStack Tezzaron technology is also described, revealing a high fill-factor of about 80%.

  18. Wound fluids from human pressure ulcers contain elevated matrix metalloproteinase levels and activity compared to surgical wound fluids.

    PubMed

    Yager, D R; Zhang, L Y; Liang, H X; Diegelmann, R F; Cohen, I K

    1996-11-01

    Fluid from acute surgical wounds and from nonhealing pressure ulcers was examined for the presence of several matrix metalloproteinases. Gelatin zymography demonstrated the presence of two major gelatinases with apparent molecular masses of 72 kDa and 92 kDa and two minor gelatinases with apparent mobilities of 68 kDa and 125 kDa. Antigen-specific sera identified the 72-kDa protein as matrix melloproteinase-2. The same sera also reacted with the 68-kDa protein, which is consistent with it being an activated form of matrix metalloproteinase-2. Antigen-specific sera identified the 92-kDa and 125-kDa proteins as matrix metalloproteinase-9. Levels of matrix metalloproteinase-2 and matrix metalloproteinase-9 were elevated more than 10-fold and 25-fold, respectively, in fluids from pressure ulcers compared with fluids from healing wounds. Examination of total potential and actual collagenolytic activity revealed that fluid from pressure ulcers contained significantly greater levels of both total and active collagenase compared with that of acute surgical wounds. In addition, an enzyme-linked immunosorbent assay demonstrated that fluids from pressure ulcers contained significantly more collagenase complexed with the inhibitor, tissue inhibitor of metalloproteinases. Together, these observations suggest that an imbalance exists between levels of matrix metalloproteinases and their inhibitors in the fluids of pressure ulcers and that this is primarily the result of elevated levels of the matrix metalloproteinases. The presence of excessive levels of activated forms of matrix-degrading enzymes at the wound surface of pressure ulcers may impede the healing of these wounds and may be relevant to the development of new rationales for treatment.

  19. High-performance single-crystalline arsenic-doped indium oxide nanowires for transparent thin-film transistors and active matrix organic light-emitting diode displays.

    PubMed

    Chen, Po-Chiang; Shen, Guozhen; Chen, Haitian; Ha, Young-geun; Wu, Chao; Sukcharoenchoke, Saowalak; Fu, Yue; Liu, Jun; Facchetti, Antonio; Marks, Tobin J; Thompson, Mark E; Zhou, Chongwu

    2009-11-24

    We report high-performance arsenic (As)-doped indium oxide (In(2)O(3)) nanowires for transparent electronics, including their implementation in transparent thin-film transistors (TTFTs) and transparent active-matrix organic light-emitting diode (AMOLED) displays. The As-doped In(2)O(3) nanowires were synthesized using a laser ablation process and then fabricated into TTFTs with indium-tin oxide (ITO) as the source, drain, and gate electrodes. The nanowire TTFTs on glass substrates exhibit very high device mobilities (approximately 1490 cm(2) V(-1) s(-1)), current on/off ratios (5.7 x 10(6)), steep subthreshold slopes (88 mV/dec), and a saturation current of 60 microA for a single nanowire. By using a self-assembled nanodielectric (SAND) as the gate dielectric, the device mobilities and saturation current can be further improved up to 2560 cm(2) V(-1) s(-1) and 160 microA, respectively. All devices exhibit good optical transparency (approximately 81% on average) in the visible spectral range. In addition, the nanowire TTFTs were utilized to control green OLEDs with varied intensities. Furthermore, a fully integrated seven-segment AMOLED display was fabricated with a good transparency of 40% and with each pixel controlled by two nanowire transistors. This work demonstrates that the performance enhancement possible by combining nanowire doping and self-assembled nanodielectrics enables silicon-free electronic circuitry for low power consumption, optically transparent, high-frequency devices assembled near room temperature.

  20. Using Video-Enhanced Activity Schedules and Matrix Training to Teach Sociodramatic Play to a Child with Autism

    ERIC Educational Resources Information Center

    Dauphin, Melissa; Kinney, Elisabeth M.; Stromer, Robert; Koegel, R. L.

    2004-01-01

    We evaluated an intervention package for teaching generative sociodramatic play activities to a young boy with an autism spectrum disorder. In Phase 1, the boy learned computer activity schedules that featured embedded video models of what to say and do. A 3 x 3 instructional matrix defined 9 activities to be performed involving combinations of 3…

  1. The matrix-binding domain of microfibril-associated glycoprotein-1 targets active connective tissue growth factor to a fibroblast-produced extracellular matrix.

    PubMed

    Weinbaum, Justin S; Tranquillo, Robert T; Mecham, Robert P

    2010-11-10

    It is advantageous to use biomaterials in tissue engineering that stimulate extracellular matrix (ECM) production by the cellular component. Connective tissue growth factor (CTGF) stimulates type I collagen (COL1A1) transcription, but is functionally limited as a free molecule. Using a matrix-binding domain (MBD) from microfibril-associated glycoprotein-1, the fusion protein MBD-CTGF was targeted to the ECM and tested for COL1A1 transcriptional activation. MBD-CTGF produced by the ECM-synthesizing fibroblasts, or provided exogenously, localized to the elastic fiber ECM. MBD-CTGF, but not CTGF alone, led to a two-fold enhancement of COL1A1 expression. This study introduces a targeting technology that can be used to elevate collagen transcription in engineered tissues and thereby improve tissue mechanics.

  2. [Regulation of biochar on matrix enzyme activities and microorganisms around cucumber roots under continuous cropping].

    PubMed

    Zou, Chun-jiao; Zhang, Yong-yong; Zhang, Yi-ming; Guo, Xiao-ou; Li, Ming-jing; Li, Tian-lai

    2015-06-01

    The effects of addition of biochar on the matrix enzymes activity, microorganisms population and microbial community structure were evaluated under cucumber continuous cropping for 6 years (11 rotations). Cucumbers were grown in pots in greenhouse with 5% or 3% of medium (by mass) substituted with biochar. The control consisted of medium alone without biochar. The results showed that the activity of peroxidase was significantly improved to the level of the first rotation crop form 30 to 120 d after planting in both biochar treatments, with the effect of 5% biochar being more significant than that of 3% biochar. However, the neutral phosphatase activity was markedly reduced after biochar treatment. The addition of 5% biochar had significant regulation effect on the activities of invertase and urease from 30 to 90 d after planting, while the addition of 3% biochar had little effect. The populations of bacteria and actinomycetes were increased and the fungi population was reduced in both biochar treatments from 30 to 90 d after planting, and the effect of 5% biochar was more significant than that of 3% biochar. Meanwhile, the addition of biochar significantly increased the diversity of the bacterial community structure. In summary, biochar had obvious regulation effect on soil enzyme activity, microorganism quantity and microbial community in continuous cropping nutrition medium. PMID:26572031

  3. Optical imaging of matrix metalloproteinase-7 activity in vivo using a proteolytic nanobeacon

    PubMed Central

    Scherer, Randy L.; VanSaun, Michael N.; McIntyre, Oliver; Matrisian, Lynn M.

    2009-01-01

    Matrix metalloproteinases (MMPs) are extracellular proteolytic enzymes involved in tumor progression. We present the in vivo detection and quantitation of MMP7 activity using a specific near-infrared polymer-based proteolytic beacon, PB-M7NIR. PB-M7NIR is a pegylated polyamidoamine PAMAM-Generation 4 dendrimer core covalently coupled to a Cy5.5 labeled peptide representing a selective substrate that monitors MMP7 activity (S, sensor), and AF750 as an internal reference to monitor relative substrate concentration (R, reference). In vivo imaging of tumors expressing MMP7 had a median S/R ratio 2.2-fold higher than a bilateral control tumor. Ex-vivo imaging of intestines of multiple intestinal neoplasia (APCMin) mice injected systemically with PB-M7NIR revealed a 6-fold increase in S/R in the adenomas of APCMin mice compared to control intestinal tissue or adenomas from MMP7-null Min mice. PB-M7NIR detected tumor sizes as small as 0.01cm2, and S/R was independent of tumor size. Histological sectioning of xenograft tumors localized the proteolytic signal to the extracellular matrix; MMP7-overexpressing tumors displayed an approximately 300-fold enhancement in S/R compared to non-expressing tumor cells. In APCMin adenomas, the proteolytic signal co-localized with the endogenously-expressed MMP7 protein with S/R ratios approximately 6-fold greater than that of normal intestinal epithelium. PB-M7NIR provides a useful reagent for the in vivo and ex-vivo quantitation and localization of MMP-selective proteolytic activity. PMID:19123982

  4. Optical imaging of matrix metalloproteinase-7 activity in vivo using a proteolytic nanobeacon.

    PubMed

    Scherer, Randy L; VanSaun, Michael N; McIntyre, J Oliver; Matrisian, Lynn M

    2008-01-01

    Matrix metalloproteinases (MMPs) are extracellular proteolytic enzymes involved in tumor progression. We present the in vivo detection and quantitation of MMP7 activity using a specific near-infrared polymer-based proteolytic beacon, PB-M7NIR. PB-M7NIR is a pegylated polyamidoamine PAMAM-Generation 4 dendrimer core covalently coupled to a Cy5.5-labeled peptide representing a selective substrate that monitors MMP7 activity (sensor) and AF750 as an internal reference to monitor relative substrate concentration (reference). In vivo imaging of tumors expressing MMP7 had a median sensor to reference ratio 2.2-fold higher than a that of a bilateral control tumor. Ex vivo imaging of intestines of multiple intestinal neoplasia (APC Min) mice injected systemically with PB-M7NIR revealed a sixfold increase in the sensor to reference ratio in the adenomas of APC Min mice compared with control intestinal tissue or adenomas from MMP7-null Min mice. PB-M7NIR detected tumor sizes as small as 0.01 cm2, and the sensor to reference ratio was independent of tumor size. Histologic sectioning of xenograft tumors localized the proteolytic signal to the extracellular matrix; MMP7-overexpressing tumors displayed an approximately 300-fold enhancement in the sensor to reference ratio compared with nonexpressing tumor cells. In APC Min adenomas, the proteolytic signal colocalized with the endogenously expressed MMP7 protein, with sensor to reference ratios approximately sixfold greater than that of normal intestinal epithelium. PB-M7NIR provides a useful reagent for the in vivo and ex vivo quantitation and localization of MMP-selective proteolytic activity.

  5. Small-Scale Readout Systems Prototype for the STAR PIXEL Detector

    SciTech Connect

    Szelezniak, Michal A.; Besson, Auguste; Colledani, Claude; Dorokhov, Andrei; Dulinski, Wojciech; Greiner, Leo C.; Himmi, Abdelkader; Hu, Christine; Matis, Howard S.; Ritter, Hans Georg; Rose, Andrew; Shabetai, Alexandre; Stezelberger, Thorsten; Sun, Xiangming; Thomas, Jim H.; Valin, Isabelle; Vu, Chinh Q.; Wieman, Howard H.; Winter, Marc

    2008-10-01

    A prototype readout system for the STAR PIXEL detector in the Heavy Flavor Tracker (HFT) vertex detector upgrade is presented. The PIXEL detector is a Monolithic Active Pixel Sensor (MAPS) based silicon pixel vertex detector fabricated in a commercial CMOS process that integrates the detector and front-end electronics layers in one silicon die. Two generations ofMAPS prototypes designed specifically for the PIXEL are discussed. We have constructed a prototype telescope system consisting of three small MAPS sensors arranged in three parallel and coaxial planes with a readout system based on the readout architecture for PIXEL. This proposed readout architecture is simple and scales to the size required to readout the final detector. The real-time hit finding algorithm necessary for data rate reduction in the 400 million pixel detector is described, and aspects of the PIXEL system integration into the existing STAR framework are addressed. The complete system has been recently tested and shown to be fully functional.

  6. The CMS pixel luminosity telescope

    NASA Astrophysics Data System (ADS)

    Kornmayer, A.

    2016-07-01

    The Pixel Luminosity Telescope (PLT) is a new complement to the CMS detector for the LHC Run II data taking period. It consists of eight 3-layer telescopes based on silicon pixel detectors that are placed around the beam pipe on each end of CMS viewing the interaction point at small angle. A fast 3-fold coincidence of the pixel planes in each telescope will provide a bunch-by-bunch measurement of the luminosity. Particle tracking allows collision products to be distinguished from beam background, provides a self-alignment of the detectors, and a continuous in-time monitoring of the efficiency of each telescope plane. The PLT is an independent luminometer, essential to enhance the robustness on the measurement of the delivered luminosity and to reduce its systematic uncertainties. This will allow to determine production cross-sections, and hence couplings, with high precision and to set more stringent limits on new particle production.

  7. Physical activity of children: a global matrix of grades comparing 15 countries.

    PubMed

    Tremblay, Mark S; Gray, Casey E; Akinroye, Kingsley; Harrington, Dierdre M; Katzmarzyk, Peter T; Lambert, Estelle V; Liukkonen, Jarmo; Maddison, Ralph; Ocansey, Reginald T; Onywera, Vincent O; Prista, Antonio; Reilly, John J; Rodríguez Martínez, María Pilar; Sarmiento Duenas, Olga L; Standage, Martyn; Tomkinson, Grant

    2014-05-01

    The Active Healthy Kids Canada (AHKC) Report Card on Physical Activity for Children and Youth has been effective in powering the movement to get kids moving by influencing priorities, policies, and practice in Canada. The AHKC Report Card process was replicated in 14 additional countries from 5 continents using 9 common indicators (Overall Physical Activity, Organized Sport Participation, Active Play, Active Transportation, Sedentary Behavior, Family and Peers, School, Community and Built Environment, and Government Strategies and Investments), a harmonized process and a standardized grading framework. The 15 Report Cards were presented at the Global Summit on the Physical Activity of Children in Toronto on May 20, 2014. The consolidated findings are summarized here in the form of a global matrix of grades. There is a large spread in grades across countries for most indicators. Countries that lead in certain indicators lag in others. Overall, the grades for indicators of physical activity (PA) around the world are low/poor. Many countries have insufficient information to assign a grade, particularly for the Active Play and Family and Peers indicators. Grades for Sedentary Behaviors are, in general, better in low income countries. The Community and Built Environment indicator received high grades in high income countries and notably lower grades in low income countries. There was a pattern of higher PA and lower sedentary behavior in countries reporting poorer infrastructure, and lower PA and higher sedentary behavior in countries reporting better infrastructure, which presents an interesting paradox. Many surveillance and research gaps and weaknesses were apparent. International cooperation and cross-fertilization is encouraged to tackle existing challenges, understand underlying mechanisms, derive innovative solutions, and overcome the expanding childhood inactivity crisis. PMID:25426906

  8. Toward Active-Matrix Lab-On-A-Chip: Programmable Electrofluidic control Enaled by Arrayed Oxide Thin Film Transistors

    SciTech Connect

    Noh, Joo Hyon; Noh, Jiyong; Kreit, Eric; Heikenfeld, Jason; Rack, Philip D

    2012-01-01

    Agile micro- and nano-fluidic control is critical to numerous life science and chemical science synthesis as well as kinetic and thermodynamic studies. To this end, we have demonstrated the use of thin film transistor arrays as an active matrix addressing method to control an electrofluidic array. Because the active matrix method minimizes the number of control lines necessary (m + n lines for the m x n element array), the active matrix addressing method integrated with an electrofluidic platform can be a significant breakthrough for complex electrofluidic arrays (increased size or resolution) with enhanced function, agility and programmability. An amorphous indium gallium zinc oxide (a-IGZO) semiconductor active layer is used because of its high mobility of 1-15 cm{sup 2} V{sup -1} s{sup -1}, low-temperature processing and transparency for potential spectroscopy and imaging. Several electrofluidic functionalities are demonstrated using a simple 2 x 5 electrode array connected to a 2 x 5 IGZO thin film transistor array with the semiconductor channel width of 50 {mu}m and mobility of 6.3 cm{sup 2} V{sup -1} s{sup -1}. Additionally, using the TFT device characteristics, active matrix addressing schemes are discussed as the geometry of the electrode array can be tailored to act as a storage capacitor element. Finally, requisite material and device parameters are discussed in context with a VGA scale active matrix addressed electrofluidic platform.

  9. Coherence experiments in single-pixel digital holography.

    PubMed

    Liu, Jung-Ping; Guo, Chia-Hao; Hsiao, Wei-Jen; Poon, Ting-Chung; Tsang, Peter

    2015-05-15

    In optical scanning holography (OSH), the coherence properties of the acquired holograms depend on the single-pixel size, i.e., the active area of the photodetector. For the first time, to the best of our knowledge, we have demonstrated coherent, partial coherent, and incoherent three-dimensional (3D) imaging by experiment in such a single-pixel digital holographic recording system. We have found, for the incoherent mode of OSH, in which the detector of the largest active area is applied, the 3D location of a diffusely reflecting object can be successfully retrieved without speckle noise. For the partial coherent mode employing a smaller pixel size of the detector, significant speckles and randomly distributed bright spots appear among the reconstructed images. For the coherent mode of OSH when the size of the pixel is vanishingly small, the bright spots disappear. However, the speckle remains and the signal-to-noise ratio is low. PMID:26393741

  10. Stellar photometry with big pixels

    SciTech Connect

    Buonanno, R.; Iannicola, G.; European Southern Observatory, Garching )

    1989-03-01

    A new software for stellar photometry in crowded fields is presented. This software overcomes the limitations present in a traditional package like ROMAFOT when the pixel size of the detector is comparable to the scale length of point images. This is the case, for instance, with the Hubble Space Telescope-Wide Field Camera and, partially, with the Planetary Camera. The numerical solution presented here is compared to the technical solution of obtaining more exposures of the same field, each shifted by a fraction of pixel. This software will be available in MIDAS. 11 refs.

  11. Density-matrix renormalization group algorithm with multi-level active space.

    PubMed

    Ma, Yingjin; Wen, Jing; Ma, Haibo

    2015-07-21

    The density-matrix renormalization group (DMRG) method, which can deal with a large active space composed of tens of orbitals, is nowadays widely used as an efficient addition to traditional complete active space (CAS)-based approaches. In this paper, we present the DMRG algorithm with a multi-level (ML) control of the active space based on chemical intuition-based hierarchical orbital ordering, which is called as ML-DMRG with its self-consistent field (SCF) variant ML-DMRG-SCF. Ground and excited state calculations of H2O, N2, indole, and Cr2 with comparisons to DMRG references using fixed number of kept states (M) illustrate that ML-type DMRG calculations can obtain noticeable efficiency gains. It is also shown that the orbital re-ordering based on hierarchical multiple active subspaces may be beneficial for reducing computational time for not only ML-DMRG calculations but also DMRG ones with fixed M values. PMID:26203012

  12. [Regulation of cell activity by the extracellular matrix: the concept of matrikines].

    PubMed

    Maquart, F X; Siméon, A; Pasco, S; Monboisse, J C

    1999-01-01

    The activity of connective tissue cells is modulated by a number of factors present in their environment. In addition to the soluble factors such as hormones, cytokines or growth factors, cells also receive signals from the surrounding extracellular matrix (ECM) macromolecules. Moreover, they may degrade the ECM proteins and liberate peptides which may by themselves constitute new signals for the surrounding cells. Therefore, an actual regulation loop exists in connective tissue, constituted by peptides generated by ECM degradation and connective tissue cells. The term of "matrikine" has been proposed to designate such ECM-derived peptides able to regulate cell activity. In this review, we summarize some data obtained in our laboratory with two different matrikines: the tripeptide glycyl-histidyl-lysine (GHK) and the heptapeptide cysteinyl-asparaginyl-tyrosyl-tyrosyl-seryl-asparaginyl-serine (CNYYSNS). GHK is a potent activator of ECM synthesis and remodeling, whereas CNYYSNS is able to inhibit polymorphonuclear leukocytes activation and decrease the invasive capacities of cancer cells. PMID:10689625

  13. Pixel Analysis and Plasma Dynamics Characterized by Photospheric Spectral Data

    NASA Astrophysics Data System (ADS)

    Rasca, A.; Chen, J.; Pevtsov, A. A.

    2015-12-01

    Continued advances in solar observations have led to higher-resolution magnetograms and surface (photospheric) images, revealing bipolar magnetic features operating near the resolution limit during emerging flux events and other phenomena used to predict solar eruptions responsible for geomagnetic plasma disturbances. However, line of sight (LOS) magnetogram pixels only contain the net uncanceled magnetic flux, which is expected to increase for fixed regions as resolution limits improve. A pixel dynamics model utilizing Stokes I spectral profiles was previously-used to quantify changes in the Doppler shift, width, asymmetry, and tail flatness of Fe I lines at 6301.5 and 6302.5 Å and used pixel-by-pixel line profile fluctuations to characterize quiet and active regions on the Sun. We use this pixel dynamics model with circularly polarized photospheric data (e.g., SOLIS data) to estimate plasma dynamic properties at a sub-pixel level. The analysis can be extended to include the full Stokes parameters and study signatures of magnetic fields and coupled plasma properties on sub-pixel scales.

  14. Matrix metalloproteinase-2 of human carotid atherosclerotic plaques promotes platelet activation. Correlation with ischaemic events.

    PubMed

    Lenti, Massimo; Falcinelli, Emanuela; Pompili, Marcella; de Rango, Paola; Conti, Valentina; Guglielmini, Giuseppe; Momi, Stefania; Corazzi, Teresa; Giordano, Giuseppe; Gresele, Paolo

    2014-06-01

    Purified active matrix metalloproteinase-2 (MMP-2) is able to promote platelet aggregation. We aimed to assess the role of MMP-2 expressed in atherosclerotic plaques in the platelet-activating potential of human carotid plaques and its correlation with ischaemic events. Carotid plaques from 81 patients undergoing endarterectomy were tested for pro-MMP-2 and TIMP-2 content by zymography and ELISA. Plaque extracts were incubated with gel-filtered platelets from healthy volunteers for 2 minutes before the addition of a subthreshold concentration of thrombin receptor activating peptide-6 (TRAP-6) and aggregation was assessed. Moreover, platelet deposition on plaque extracts immobilised on plastic coverslips under high shear-rate flow conditions was measured. Forty-three plaque extracts (53%) potentiated platelet aggregation (+233 ± 26.8%), an effect prevented by three different specific MMP-2 inhibitors (inhibitor II, TIMP-2, moAb anti-MMP-2). The pro-MMP-2/TIMP-2 ratio of plaques potentiating platelet aggregation was significantly higher than that of plaques not potentiating it (3.67 ± 1.21 vs 1.01 ± 0.43, p<0.05). Moreover, the platelet aggregation-potentiating effect, the active-MMP-2 content and the active MMP-2/pro-MMP-2 ratio of plaque extracts were significantly higher in plaques from patients who developed a subsequent major cardiovascular event. In conclusion, atherosclerotic plaques exert a prothrombotic effect by potentiating platelet activation due to their content of MMP-2; an elevated MMP-2 activity in plaques is associated with a higher rate of subsequent ischaemic cerebrovascular events. PMID:24499865

  15. The matrix effect of blueberry, oat meal and milk on polyphenols, antioxidant activity and potential bioavailability.

    PubMed

    Cebeci, Fatma; Şahin-Yeşilçubuk, Neşe

    2014-02-01

    In recent years, ready-to eat breakfast cereals prepared with fruit ingredients have gained particular attention due to their polyphenolic contents and health promoting effects. In this study, the matrix effect of blueberry, oat meal, whole milk or skimmed milk on polyphenols, antioxidative potential as well as their potential bioavailability were investigated. The phenolic properties of whole milk, skimmed milk, blueberry and oat meal were investigated and the changes in combinations of the ingredients were determined. Milk addition decreased the total phenolic, flavonoid and anthocyanin content of samples statistically and had negative effect on antioxidant activity showing differences among different methods. According to HPLC results, it was not possible to detect catechin in mixtures due to milk addition. In vitro digestion method was used to determine potential bioavailability of phenolic compounds. According to in vitro digestion procedure results, whole or skimmed milk did not affect the total phenolic content of the proportion passing to the blood from intestine.

  16. Novel Digital Driving Method Using Dual Scan for Active Matrix Organic Light-Emitting Diode Displays

    NASA Astrophysics Data System (ADS)

    Jung, Myoung Hoon; Choi, Inho; Chung, Hoon-Ju; Kim, Ohyun

    2008-11-01

    A new digital driving method has been developed for low-temperature polycrystalline silicon, transistor-driven, active-matrix organic light-emitting diode (AM-OLED) displays by time-ratio gray-scale expression. This driving method effectively increases the emission ratio and the number of subfields by inserting another subfield set into nondisplay periods in the conventional digital driving method. By employing the proposed modified gravity center coding, this method can be used to effectively compensate for dynamic false contour noise. The operation and performance were verified by current measurement and image simulation. The simulation results using eight test images show that the proposed approach improves the average peak signal-to-noise ratio by 2.61 dB, and the emission ratio by 20.5%, compared with the conventional digital driving method.

  17. Driving technology for improving motion quality of active-matrix organic light-emitting diode display

    NASA Astrophysics Data System (ADS)

    Kim, Jongbin; Kim, Minkoo; Kim, Jong-Man; Kim, Seung-Ryeol; Lee, Seung-Woo

    2014-09-01

    This paper reports transient response characteristics of active-matrix organic light emitting diode (AMOLED) displays for mobile applications. This work reports that the rising responses look like saw-tooth waveform and are not always faster than those of liquid crystal displays. Thus, a driving technology is proposed to improve the rising transient responses of AMOLED based on the overdrive (OD) technology. We modified the OD technology by combining it with a dithering method because the conventional OD method cannot successfully enhance all the rising responses. Our method can improve all the transitions of AMOLED without modifying the conventional gamma architecture of drivers. A new artifact is found when OD is applied to certain transitions. We propose an optimum OD selection method to mitigate the artifact. The implementation results show the proposed technology can successfully improve motion quality of scrolling texts as well as moving pictures in AMOLED displays.

  18. Density-matrix renormalization-group study of current and activity fluctuations near nonequilibrium phase transitions.

    PubMed

    Gorissen, Mieke; Hooyberghs, Jef; Vanderzande, Carlo

    2009-02-01

    Cumulants of a fluctuating current can be obtained from a free-energy-like generating function, which for Markov processes equals the largest eigenvalue of a generalized generator. We determine this eigenvalue with the density-matrix renormalization group for stochastic systems. We calculate the variance of the current in the different phases, and at the phase transitions, of the totally asymmetric exclusion process. Our results can be described in the terms of a scaling ansatz that involves the dynamical exponent z . We also calculate the generating function of the dynamical activity (total number of configuration changes) near the absorbing-state transition of the contact process. Its scaling properties can be expressed in terms of known critical exponents. PMID:19391693

  19. High performance organic transistor active-matrix driver developed on paper substrate

    NASA Astrophysics Data System (ADS)

    Peng, Boyu; Ren, Xiaochen; Wang, Zongrong; Wang, Xinyu; Roberts, Robert C.; Chan, Paddy K. L.

    2014-09-01

    The fabrication of electronic circuits on unconventional substrates largely broadens their application areas. For example, green electronics achieved through utilization of biodegradable or recyclable substrates, can mitigate the solid waste problems that arise at the end of their lifespan. Here, we combine screen-printing, high precision laser drilling and thermal evaporation, to fabricate organic field effect transistor (OFET) active-matrix (AM) arrays onto standard printer paper. The devices show a mobility and on/off ratio as high as 0.56 cm2V-1s-1 and 109 respectively. Small electrode overlap gives rise to a cut-off frequency of 39 kHz, which supports that our AM array is suitable for novel practical applications. We demonstrate an 8 × 8 AM light emitting diode (LED) driver with programmable scanning and information display functions. The AM array structure has excellent potential for scaling up.

  20. Matrix metalloproteinases 2 and 9 and MMP9/NGAL complex activity in women with PCOS.

    PubMed

    Ranjbaran, Javad; Farimani, Marzieh; Tavilani, Heidar; Ghorbani, Marzieh; Karimi, Jamshid; Poormonsefi, Faranak; Khodadadi, Iraj

    2016-04-01

    It is believed that matrix metalloproteinases (MMPs) play important roles in follicular development and pathogenesis of polycystic ovary syndrome (PCOS). However, conflicting results are available about the alteration of MMP2 and MMP9 concentrations or activities in PCOS. In fact, there is no study entirely investigating both concentration and activity of these MMPs and serum levels of their tissue inhibitors TIMP2 and TIMP1, as well as lipocalin-bound form of MMP9 (MMP9/NGAL). Therefore, the thoroughness of previous studies is questionable. This study was conducted to determine circulatory concentration of MMP2, MMP9, MMP9/NGAL complex, TIMP1 and TIMP2 as well as gelatinase activities of MMP2, MMP9 and MMP9/NGAL complex in women with PCOS and controls. Mean age and BMI as well as serum levels of total cholesterol, triacylglycerol, HDL-C, LDL-C, fasting blood sugar (FBS), insulin, estradiol and sex hormone-binding globulin did not differ between groups, whereas a marked decrease in FSH and significant increases in LH, LH/FSH ratio, testosterone and free androgen index were observed. Women with PCOS and controls showed closed concentrations of MMP2, MMP9, MMP9/NGAL, TIMP1 and TIMP2. Gelatinase activity of MMP9 was found significantly higher in PCOS than in controls (64.53±15.32 vs 44.61±18.95 respectively) while patients and healthy subjects showed similar activities of MMP2 and MMP9/NGAL complex. Additionally, PCOS patients showed a higher MMP9/TIMP1 ratio compared with control women. Direct correlations were also observed between circulatory MMP9 level and the concentration and activity of MMP9/NGAL complex. In conclusion, based on the results of present study, we believe that MMP9 may be involved in the pathogenesis of PCOS.

  1. Edge pixel response studies of edgeless silicon sensor technology for pixellated imaging detectors

    NASA Astrophysics Data System (ADS)

    Maneuski, D.; Bates, R.; Blue, A.; Buttar, C.; Doonan, K.; Eklund, L.; Gimenez, E. N.; Hynds, D.; Kachkanov, S.; Kalliopuska, J.; McMullen, T.; O'Shea, V.; Tartoni, N.; Plackett, R.; Vahanen, S.; Wraight, K.

    2015-03-01

    Silicon sensor technologies with reduced dead area at the sensor's perimeter are under development at a number of institutes. Several fabrication methods for sensors which are sensitive close to the physical edge of the device are under investigation utilising techniques such as active-edges, passivated edges and current-terminating rings. Such technologies offer the goal of a seamlessly tiled detection surface with minimum dead space between the individual modules. In order to quantify the performance of different geometries and different bulk and implant types, characterisation of several sensors fabricated using active-edge technology were performed at the B16 beam line of the Diamond Light Source. The sensors were fabricated by VTT and bump-bonded to Timepix ROICs. They were 100 and 200 μ m thick sensors, with the last pixel-to-edge distance of either 50 or 100 μ m. The sensors were fabricated as either n-on-n or n-on-p type devices. Using 15 keV monochromatic X-rays with a beam spot of 2.5 μ m, the performance at the outer edge and corners pixels of the sensors was evaluated at three bias voltages. The results indicate a significant change in the charge collection properties between the edge and 5th (up to 275 μ m) from edge pixel for the 200 μ m thick n-on-n sensor. The edge pixel performance of the 100 μ m thick n-on-p sensors is affected only for the last two pixels (up to 110 μ m) subject to biasing conditions. Imaging characteristics of all sensor types investigated are stable over time and the non-uniformities can be minimised by flat-field corrections. The results from the synchrotron tests combined with lab measurements are presented along with an explanation of the observed effects.

  2. Multimodal imaging reveals temporal and spatial microglia and matrix metalloproteinase activity after experimental stroke

    PubMed Central

    Zinnhardt, Bastian; Viel, Thomas; Wachsmuth, Lydia; Vrachimis, Alexis; Wagner, Stefan; Breyholz, Hans-Jörg; Faust, Andreas; Hermann, Sven; Kopka, Klaus; Faber, Cornelius; Dollé, Frédéric; Pappata, Sabina; Planas, Anna M; Tavitian, Bertrand; Schäfers, Michael; Sorokin, Lydia M; Kuhlmann, Michael T; Jacobs, Andreas H

    2015-01-01

    Stroke is the most common cause of death and disability from neurologic disease in humans. Activation of microglia and matrix metalloproteinases (MMPs) is involved in positively and negatively affecting stroke outcome. Novel, noninvasive, multimodal imaging methods visualizing microglial and MMP alterations were employed. The spatio-temporal dynamics of these parameters were studied in relation to blood flow changes. Micro positron emission tomography (μPET) using [18F]BR-351 showed MMP activity within the first days after transient middle cerebral artery occlusion (tMCAo), followed by increased [18F]DPA-714 uptake as a marker for microglia activation with a maximum at 14 days after tMCAo. The inflammatory response was spatially located in the infarct core and in adjacent (penumbral) tissue. For the first time, multimodal imaging based on PET, single photon emission computed tomography, and magnetic resonance imaging revealed insight into the spatio-temporal distribution of critical parameters of poststroke inflammation. This allows further evaluation of novel treatment paradigms targeting the postischemic inflammation. PMID:26126867

  3. A Matrix Metalloproteinase-1/Protease Activated Receptor-1 signaling axis promotes melanoma invasion and metastasis

    PubMed Central

    Blackburn, Jessica S.; Liu, Ingrid; Coon, Charles I.; Brinckerhoff, Constance E.

    2009-01-01

    Hallmarks of malignant melanoma are its propensity to metastasize and its resistance to treatment, giving patients with advanced disease a poor prognosis. The transition of melanoma from non-invasive radial growth phase (RGP) to invasive and metastatically competent vertical growth phase (VGP) is a major step in tumor progression, yet the mechanisms governing this transformation are unknown. Matrix Metalloproteinase-1 (MMP-1) is highly expressed by VGP melanomas, and is thought to contribute to melanoma progression by degrading type I collagen within the skin to facilitate melanoma invasion. Protease activated receptor-1 (PAR-1) is activated by MMP-1, and is also expressed by VGP melanomas. However, the effects MMP-1 signaling through PAR-1 have not been examined in melanoma. Here, we demonstrate that an MMP-1/PAR-1 signaling axis exists in VGP melanoma, and is necessary for melanoma invasion. Introduction of MMP-1 into RGP melanoma cells induced gene expression associated with tumor progression and promoted invasion in vitro, and enhanced tumor growth and conferred metastatic capability in vivo. This study demonstrates that both the type I collagenase and PAR-1 activating functions of MMP-1 are required for melanoma progression, and suggests that MMP-1 may be a major contributor to the transformation of melanoma from non-invasive to malignant disease. PMID:19734937

  4. Proliferative effects of apical, but not basal, matrix metalloproteinase-7 activity in polarized MDCK cells

    SciTech Connect

    Harrell, Permila C.; McCawley, Lisa J.; Fingleton, Barbara; McIntyre, J. Oliver; Matrisian, Lynn M. . E-mail: lynn.matrisian@vanderbilt.edu

    2005-02-15

    Matrix metalloproteinase-7 (MMP-7) is primarily expressed in glandular epithelium. Therefore, its mechanism of action may be influenced by its regulated vectorial release to either the apical and/or basolateral compartments, where it would act on its various substrates. To gain a better understanding of where MMP-7 is released in polarized epithelium, we have analyzed its pattern of secretion in polarized MDCK cells expressing stably transfected human MMP-7 (MDCK-MMP-7), and HCA-7 and Caco2 human colon cancer cell lines. In all cell lines, latent MMP-7 was secreted to both cellular compartments, but was 1.5- to 3-fold more abundant in the basolateral compartment as compared to the apical. However, studies in the MDCK system demonstrated that MMP-7 activity was 2-fold greater in the apical compartment of MDCK-MMP-7{sup HIGH}-polarized monolayers, which suggests the apical co-release of an MMP-7 activator. In functional assays, MMP-7 over-expression increased cell saturation density as a result of increased cell proliferation with no effect on apoptosis. Apical MMP-7 activity was shown to be responsible for the proliferative effect, which occurred, as demonstrated by media transfer experiments, through cleavage of an apical substrate and not through the generation of a soluble factor. Taken together, our findings demonstrate the importance of MMP-7 secretion in relation to its mechanism of action when expressed in a polarized epithelium.

  5. Pyrophosphate Stimulates Differentiation, Matrix Gene Expression and Alkaline Phosphatase Activity in Osteoblasts

    PubMed Central

    Pujari-Palmer, Michael; Pujari-Palmer, Shiuli; Lu, Xi; Lind, Thomas; Melhus, Håkan; Engstrand, Thomas; Karlsson-Ott, Marjam; Engqvist, Hakan

    2016-01-01

    Pyrophosphate is a potent mitogen, capable of stimulating proliferation in multiple cell types, and a critical participant in bone mineralization. Pyrophosphate can also affect the resorption rate and bioactivity of orthopedic ceramics. The present study investigated whether calcium pyrophosphate affected proliferation, differentiation and gene expression in early (MC3T3 pre-osteoblast) and late stage (SAOS-2 osteosarcoma) osteoblasts. Pyrophosphate stimulated peak alkaline phosphatase activity by 50% and 150% at 100μM and 0.1μM in MC3T3, and by 40% in SAOS-2. The expression of differentiation markers collagen 1 (COL1), alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN) were increased by an average of 1.5, 2, 2 and 3 fold, by high concentrations of sodium pyrophosphate (100μM) after 7 days of exposure in MC3T3. COX-2 and ANK expression did not differ significantly from controls in either treatment group. Though both high and low concentrations of pyrophosphate stimulate ALP activity, only high concentrations (100μM) stimulated osteogenic gene expression. Pyrophosphate did not affect proliferation in either cell type. The results of this study confirm that chronic exposure to pyrophosphate exerts a physiological effect upon osteoblast differentiation and ALP activity, specifically by stimulating osteoblast differentiation markers and extracellular matrix gene expression. PMID:27701417

  6. Computational characterization of ketone-ketal transformations at the active site of matrix metalloproteinases.

    PubMed

    Khrenova, Maria G; Nemukhin, Alexander V; Savitsky, Alexander P

    2014-04-24

    We modeled the first steps of hydrolysis reactions of a natural oligopeptide substrate of matrix metalloproteinase MMP-2 as well as of a substrate analogue. In the latter, the scissile amide group is substituted by a ketomethylene group which can be transformed to the ketal group upon binding of this compound to the enzyme active site. According to our quantum mechanical-molecular mechanical (QM/MM) calculations, the reaction of the ketone-ketal transformation proceeds with a low energy barrier (3.4 kcal/mol) and a high equilibrium constant (10(4)). The reaction product with the ketal group formed directly at the active site of the enzyme works as an inhibitor that chelates the zinc ion. On the other hand, the oligopeptide mimetic retains molecular groups responsible for binding of this compound to the enzyme active site. This example illustrates a strategy to design MMP inhibitors in situ by using data on binding specificity of substrates to a particular type of MMP and details of the reaction mechanism. PMID:24684684

  7. Activity of lung neutrophils and matrix metalloproteinases in cyclophosphamide-treated mice with experimental sepsis

    PubMed Central

    Hirsh, Mark; Carmel, Julie; Kaplan, Viktoria; Livne, Erella; Krausz, Michael M

    2004-01-01

    Sepsis in patients receiving chemotherapy may result in acute respiratory distress syndrome, despite decreased number of blood neutrophils [polymorphonuclear neutrophils (PMNs)]. In the present study, we investigated the correlation of cyclophosphamide (CY)-induced neutropenia with the destructive potential of lung PMN in respect to formation of septic acute lung injury (ALI). Mice were treated with 250 mg/kg of CY or saline (control) and subjected to cecal ligation and puncture (CLP) or sham operation. ALI was verified by histological examination. Lung PMNs and matrix metalloproteinases (MMPs) were assessed by flow cytometry and gelatin zymography. CLP in CY-treated mice induced a typical lung injury. Despite profound neutropenia, CY treatment did not attenuate CLP-induced ALI. This might relate to only a partial suppression of PMN: CY has significantly reduced PMN influx into the lungs (P = 0.008) and suppressed their oxidative metabolism, but had no suppressive effect on degranulation (P = 0.227) and even induced MMP-9 activity (P = 0.0003). In CY-untreated animals, peak of CLP-induced ALI coincided with massive PMN influx (P = 0.013), their maximal degranulation (P = 0.014) and activation of lung MMP-9 (P = 0.002). These findings may indicate an important role of the residual lung PMN and activation of MMP-9 in septic lung injury during CY chemotherapy. PMID:15255968

  8. Dentin phosphophoryn in the matrix activates AKT and mTOR signaling pathway to promote preodontoblast survival and differentiation

    PubMed Central

    Eapen, Asha; George, Anne

    2015-01-01

    Dentin phosphophoryn (DPP) is an extracellular matrix protein synthesized by odontoblasts. It is highly acidic and the phosphorylated protein possesses a strong affinity for calcium ions. Therefore, DPP in the extracellular matrix can promote hydroxyapatite nucleation and can regulate the size of the growing crystal. Besides its calcium binding property, DPP can initiate signaling functions from the ECM (Extracellular matrix). The signals that promote the cytodifferentiation of preodontoblasts to fully functional odontoblasts are not known. In this study, we demonstrate that preodontoblasts on a DPP matrix, generates mechanical and biochemical signals. This is initiated by the ligation of the integrins with the RGD containing DPP. The downstream biochemical response observed is the activation of the AKT(protein kinase B) and mTOR (mammalian target of rapamycin) signaling pathways leading to the activation of the transcription factor NF-κB (Nuclear factor κB). Terminal differentiation of the preodontoblasts was assessed by identifying phosphate and calcium deposits in the matrix using von Kossa and Alizarin red staining respectively. Identifying the signaling pathways initiated by DPP in the dentin matrix would help in devising strategies for dentin tissue engineering. PMID:26300786

  9. PPAR{gamma} agonist pioglitazone reduces matrix metalloproteinase-9 activity and neuronal damage after focal cerebral ischemia

    SciTech Connect

    Lee, Seong-Ryong; Kim, Hahn-Young; Hong, Jung-Suk; Baek, Won-Ki; Park, Jong-Wook

    2009-02-27

    Pioglitazone, a peroxisome proliferator-activated receptor gamma (PPAR{gamma}) agonist, has shown protective effects against ischemic insult in various tissues. Pioglitazone is also reported to reduce matrix metalloproteinase (MMP) activity. MMPs can remodel extracellular matrix components in many pathological conditions. The current study was designed to investigate whether the neuroprotection of pioglitazone is related to its MMP inhibition in focal cerebral ischemia. Mice were subjected to 90 min focal ischemia and reperfusion. In gel zymography, pioglitazone reduced the upregulation of active form of MMP-9 after ischemia. In in situ zymograms, pioglitazone also reduced the gelatinase activity induced by ischemia. After co-incubation with pioglitazone, in situ gelatinase activity was directly reduced. Pioglitazone reduced the infarct volume significantly compared with controls. These results demonstrate that pioglitazone may reduce MMP-9 activity and neuronal damage following focal ischemia. The reduction of MMP-9 activity may have a possible therapeutic effect for the management of brain injury after focal ischemia.

  10. The role of valvular endothelial cell paracrine signaling and matrix elasticity on valvular interstitial cell activation.

    PubMed

    Gould, Sarah T; Matherly, Emily E; Smith, Jennifer N; Heistad, Donald D; Anseth, Kristi S

    2014-04-01

    The effects of valvular endothelial cell (VlvEC) paracrine signaling on VIC phenotype and nodule formation were tested using a co-culture platform with physiologically relevant matrix elasticities and diffusion distance. 100 μm thin poly(ethylene glycol) (PEG) hydrogels of 3-27 kPa Young's moduli were fabricated in transwell inserts. VICs were cultured on the gels, as VIC phenotype is known to change significantly within this range, while VlvECs lined the underside of the membrane. Co-culture with VlvECs significantly reduced VIC activation to the myofibroblast phenotype on all gels with the largest percent decrease on the 3 kPa gels (~70%), while stiffer gels resulted in approximately 20-30% decrease. Additionally, VlvECs significantly reduced αSMA protein expression (~2 fold lower) on both 3 and 27 kPa gels, as well as the number (~2 fold lower) of nodules formed on the 27 kPa gels. Effects of VlvECs were prevented when nitric oxide (NO) release was inhibited with l-NAME, suggesting that VlvEC produced NO inhibits VIC activation. Withdrawal of l-NAME after 3, 5, and 7 days with restoration of VlvEC NO production for 2 additional days led to a partial reversal of VIC activation (~25% decrease). A potential mechanism by which VlvEC produced NO reduced VIC activation was studied by inhibiting initial and mid-stage cGMP pathway molecules. Inhibition of soluble guanylyl cyclase (sGC) with ODQ or protein kinase G (PKG) with RBrcGMP or stimulation of Rho kinase (ROCK) with LPA, abolished VlvEC effects on VIC activation. This work contributes substantially to the understanding of the valve endothelium's role in preventing VIC functions associated with aortic valve stenosis initiation and progression.

  11. Distribution and relative activity of matrix metalloproteinase-2 in human coronal dentin

    PubMed Central

    Boushell, Lee W; Kaku, Masaru; Mochida, Yoshiyuki; Yamauchi, Mitsuo

    2011-01-01

    The presence of matrix metalloproteinase-2 (MMP-2) in dentin has been reported, but its distribution and activity level in mature human coronal dentin are not well understood. The purpose of this study was to determine the MMP-2 distribution and relative activity in demineralized dentin. Crowns of twenty eight human molars were sectioned into inner (ID), middle (MD), and outer dentin (OD) regions and demineralized. MMP-2 was extracted with 0.33 mol·L−1 EDTA/2 mol·L−1 guanidine-HCl, pH 7.4, and MMP-2 concentration was estimated with enzyme-linked immunoabsorbant assay (ELISA). Further characterization was accomplished by Western blotting analysis and gelatin zymography. The mean concentrations of MMP-2 per mg dentin protein in the dentin regions were significantly different (P=0.043): 0.9 ng (ID), 0.4 ng (MD), and 2.2 ng (OD), respectively. The pattern of MMP-2 concentration was OD>ID>MD. Western blotting analysis detected ∼66 and ∼72 kDa immunopositive proteins corresponding to pro- and mature MMP-2, respectively, in the ID and MD, and a ∼66 kDa protein in the OD. Gelatinolytic activity consistent with MMP-2 was detected in all regions. Interestingly, the pattern of levels of Western blot immunodetection and gelatinolytic activity was MD>ID>OD. The concentration of MMP-2 in human coronal dentin was highest in the region of dentin that contains the dentinoenamel junction and least in the middle region of dentin. However, levels of Western blot immunodetection and gelatinolytic activity did not correlate with the estimated regional concentrations of MMP-2, potentially indicating region specific protein interactions. PMID:22010577

  12. Osteoblast-released Matrix Vesicles, Regulation of Activity and Composition by Sulfated and Non-sulfated Glycosaminoglycans.

    PubMed

    Schmidt, Johannes R; Kliemt, Stefanie; Preissler, Carolin; Moeller, Stephanie; von Bergen, Martin; Hempel, Ute; Kalkhof, Stefan

    2016-02-01

    Our aging population has to deal with the increasing threat of age-related diseases that impair bone healing. One promising therapeutic approach involves the coating of implants with modified glycosaminoglycans (GAGs) that mimic the native bone environment and actively facilitate skeletogenesis. In previous studies, we reported that coatings containing GAGs, such as hyaluronic acid (HA) and its synthetically sulfated derivative (sHA1) as well as the naturally low-sulfated GAG chondroitin sulfate (CS1), reduce the activity of bone-resorbing osteoclasts, but they also induce functions of the bone-forming cells, the osteoblasts. However, it remained open whether GAGs influence the osteoblasts alone or whether they also directly affect the formation, composition, activity, and distribution of osteoblast-released matrix vesicles (MV), which are supposed to be the active machinery for bone formation. Here, we studied the molecular effects of sHA1, HA, and CS1 on MV activity and on the distribution of marker proteins. Furthermore, we used comparative proteomic methods to study the relative protein compositions of isolated MVs and MV-releasing osteoblasts. The MV proteome is much more strongly regulated by GAGs than the cellular proteome. GAGs, especially sHA1, were found to severely impact vesicle-extracellular matrix interaction and matrix vesicle activity, leading to stronger extracellular matrix formation and mineralization. This study shows that the regulation of MV activity is one important mode of action of GAGs and provides information on underlying molecular mechanisms.

  13. Osteoblast-released Matrix Vesicles, Regulation of Activity and Composition by Sulfated and Non-sulfated Glycosaminoglycans.

    PubMed

    Schmidt, Johannes R; Kliemt, Stefanie; Preissler, Carolin; Moeller, Stephanie; von Bergen, Martin; Hempel, Ute; Kalkhof, Stefan

    2016-02-01

    Our aging population has to deal with the increasing threat of age-related diseases that impair bone healing. One promising therapeutic approach involves the coating of implants with modified glycosaminoglycans (GAGs) that mimic the native bone environment and actively facilitate skeletogenesis. In previous studies, we reported that coatings containing GAGs, such as hyaluronic acid (HA) and its synthetically sulfated derivative (sHA1) as well as the naturally low-sulfated GAG chondroitin sulfate (CS1), reduce the activity of bone-resorbing osteoclasts, but they also induce functions of the bone-forming cells, the osteoblasts. However, it remained open whether GAGs influence the osteoblasts alone or whether they also directly affect the formation, composition, activity, and distribution of osteoblast-released matrix vesicles (MV), which are supposed to be the active machinery for bone formation. Here, we studied the molecular effects of sHA1, HA, and CS1 on MV activity and on the distribution of marker proteins. Furthermore, we used comparative proteomic methods to study the relative protein compositions of isolated MVs and MV-releasing osteoblasts. The MV proteome is much more strongly regulated by GAGs than the cellular proteome. GAGs, especially sHA1, were found to severely impact vesicle-extracellular matrix interaction and matrix vesicle activity, leading to stronger extracellular matrix formation and mineralization. This study shows that the regulation of MV activity is one important mode of action of GAGs and provides information on underlying molecular mechanisms. PMID:26598647

  14. Matrix rigidity regulates spatiotemporal dynamics of Cdc42 activity and vacuole formation kinetics of endothelial colony forming cells.

    PubMed

    Kim, Seung Joon; Wan, Qiaoqiao; Cho, Eunhye; Han, Bumsoo; Yoder, Mervin C; Voytik-Harbin, Sherry L; Na, Sungsoo

    2014-01-24

    Recent evidence has shown that endothelial colony forming cells (ECFCs) may serve as a cell therapy for improving blood vessel formation in subjects with vascular injury, largely due to their robust vasculogenic potential. The Rho family GTPase Cdc42 is known to play a primary role in this vasculogenesis process, but little is known about how extracellular matrix (ECM) rigidity affects Cdc42 activity during the process. In this study, we addressed two questions: Does matrix rigidity affect Cdc42 activity in ECFC undergoing early vacuole formation? How is the spatiotemporal activation of Cdc42 related to ECFC vacuole formation? A fluorescence resonance energy transfer (FRET)-based Cdc42 biosensor was used to examine the effects of the rigidity of three-dimensional (3D) collagen matrices on spatiotemporal activity of Cdc42 in ECFCs. Collagen matrix stiffness was modulated by varying the collagen concentration and therefore fibril density. The results showed that soft (150 Pa) matrices induced an increased level of Cdc42 activity compared to stiff (1 kPa) matrices. Time-course imaging and colocalization analysis of Cdc42 activity and vacuole formation revealed that Cdc42 activity was colocalized to the periphery of cytoplasmic vacuoles. Moreover, soft matrices generated faster and larger vacuoles than stiff matrices. The matrix-driven vacuole formation was enhanced by a constitutively active Cdc42 mutant, but significantly inhibited by a dominant-negative Cdc42 mutant. Collectively, the results suggest that matrix rigidity is a strong regulator of Cdc42 activity and vacuole formation kinetics, and that enhanced activity of Cdc42 is an important step in early vacuole formation in ECFCs.

  15. Neutrophil bactericidal activity against Staphylococcus aureus adherent on biological surfaces. Surface-bound extracellular matrix proteins activate intracellular killing by oxygen-dependent and -independent mechanisms.

    PubMed Central

    Hermann, M; Jaconi, M E; Dahlgren, C; Waldvogel, F A; Stendahl, O; Lew, D P

    1990-01-01

    The activation patterns of surface adherent neutrophils are modulated via interaction of extracellular matrix proteins with neutrophil integrins. To evaluate neutrophil bactericidal activity, Staphylococcus aureus adherent to biological surfaces were incubated with neutrophils and serum, and the survival of surface bacteria was determined. When compared to albumin-coated surfaces, the bactericidal activity of neutrophils adherent to purified human extracellular matrix was markedly enhanced (mean survival: 34.2% +/- 9.0% of albumin, P less than 0.0001) despite similar efficient ingestion of extracellular bacteria. Enhancement of killing was observed when surfaces were coated with purified constituents of extracellular matrix, i.e., fibronectin, fibrinogen, laminin, vitronectin, or type IV collagen. In addition to matrix proteins, the tetrapeptide RGDS (the sequence recognized by integrins) crosslinked to surface bound albumin was also active (survival: 74.5% +/- 5.5% of albumin, P less than 0.02), and fibronectin-increased killing was inhibited by soluble RGDS. Chemiluminescence measurements and experiments with CGD neutrophils revealed that both oxygen-dependent and -independent bactericidal mechanisms are involved. In conclusion, matrix proteins enhance intracellular bactericidal activity of adherent neutrophils, presumably by integrin recognition of RGDS-containing ligands. These results indicate a role for extracellular matrix proteins in the enhancement of the host defense against pyogenic infections. Images PMID:2394841

  16. Biomimetic Mineralization of the Alginate/Gelatin/Calcium Oxalate Matrix for Immobilization of Pectinase: Influence of Matrix on the Pectinolytic Activity.

    PubMed

    Bustamante-Vargas, Cindy Elena; de Oliveira, Débora; Valduga, Eunice; Venquiaruto, Luciana Dornelles; Paroul, Natalia; Backes, Geciane Toniazzo; Dallago, Rogério Marcos

    2016-07-01

    Pectinases catalyze the degradation of pectic substances and are used in several processes, mainly in food and textile industries. In this study, a biomimetic matrix of alginate/gelatin/calcium oxalate (AGOCa) was synthesized for the in situ immobilization via encapsulation of crude pectinase from Aspergillus niger ATCC 9642, obtaining an immobilization efficiency of about 61.7 %. To determine the performance of AGOCa matrix, this was compared to control matrices of alginate/calcium oxalate (AOxal) and alginate/water (ACa). By the evaluation of pH and temperature effects on the enzyme activity, it was observed an increase on pectinolytic activity for both three tested matrices with an increase on pH and temperature. The kinetic parameters for pectinase immobilized in the three matrices were determined using citric pectin as substrate. Values of K m of 0.003, 0.0013, and 0.0022 g mL(-1) and V max of 3.85, 4.32, and 3.17 μmol min(-1) g(-1) for AGOCa, AOxal, and ACa matrices were obtained, respectively. After 33 days of storage, the pectinase immobilized in the three different matrices kept its initial activity, but that immobilized in AGOCa presented high stability to the storage with a relative activity of about 160 %. The enzyme immobilized in AGOCa, AOxal, and ACa could be used in 10, 8, and 7 cycles, respectively, keeping 40 % of its initial activity.

  17. Differential expression of matrix metalloproteinases in activated c-ras-Ha-transfected immortalized human keratinocytes.

    PubMed Central

    Meade-Tollin, L. C.; Boukamp, P.; Fusenig, N. E.; Bowen, C. P.; Tsang, T. C.; Bowden, G. T.

    1998-01-01

    Elevated expression of matrix metalloproteinases (MMPs), a family of secreted proteinases that degrade matrix components of basement membranes and connective tissues, is strongly correlated with malignant expression in various human epithelial cancers and epithelial cancer cell lines. We have tested whether elevated levels of MMP expression are also associated with malignant progression in human cutaneous squamous cell carcinoma. Constitutive levels of expression of steady-state mRNA and of secreted protein encoded by three MMP genes (matrilysin, gelatinases A and B) were compared in a unique in vitro model of human skin carcinogenesis. This model is composed of the parental immortalized non-tumorigenic human keratinocyte line (HaCaT), and three activated c-Harvey-ras-oncogene transfected variants (A-4, I-7 and II-4). Although clone A-4 is non-tumorigenic, clones I-7 and II-4 exhibit benign and malignant tumorigenic phenotypes, respectively, after subcutaneous injection into athymic nude mice. Northern blot, Western blot, and zymogram analyses revealed three MMP-specific patterns of expression. Constitutive matrilysin mRNA expression was markedly increased in the I-7 cells compared with HaCaT, A-4 or II-4 cells. Secreted promatrilysin was distinctly increased in the tumorigenic I-7 and II-4 cells compared with the non-tumorigenic HaCaT and A-4 cells. Gelatinase A mRNA and secreted gelatinase A protein levels were increased in each transfectant compared with HaCaT. Both active and inactive forms of gelatinase A were detected. Gelatinase B transcripts were not detected, but an EDTA-inhibitable gelatinase activity comigrating with gelatinase B was moderately enhanced in both tumorigenic variants compared with the non-tumorigenic cells. Because promatrilysin and 92-kDa gelatinase secretion were increased in both benign and malignant tumorigenic cells, and not related to invasiveness in this model, it is concluded that enhanced constitutive expression of these two MMPs

  18. Human retinal pigment epithelial lysis of extracellular matrix: functional urokinase plasminogen activator receptor, collagenase, and elastase.

    PubMed Central

    Elner, Susan G

    2002-01-01

    PURPOSE: To show (1) human retinal pigment epithelial (HRPE) expression of functional urokinase plasminogen activator receptor (uPAR; CD87), (2) HRPE secretion of collagenase and elastase, (3) uPAR-dependent HRPE migration, and (4) uPAR expression in diseased human retinal tissue. METHODS: Immunohistochemistry for uPAR was performed on cultured HRPE cells and in sections of human retina. Double-immunofluorescent staining of live human RPE cells with anti-CR3 antibody (CD11b) was performed to demonstrate the physical proximity of this beta 2 integrin with uPAR and determine whether associations were dependent on RPE confluence and polarity. Extracellular proteolysis by HRPE uPAR was evaluated using fluorescent bodipy-BSA and assessed for specificity by plasminogen activator inhibitor-1 (PAI-1) inhibition. The effect of interleukin-1 beta (IL-1 beta) on uPAR expression was assessed. Collagenase and elastase secretion by unstimulated and IL-1-stimulated HRPE cells was measured by 3H-labelled collagen and elastin cleavage. HRPE-associated collagenase was also assessed by cleavage of fluorescent DQ-collagen and inhibited by phenanthroline. Using an extracellular matrix assay, the roles of uPAR and collagenase in HRPE migration were assessed. RESULTS: Immunoreactive uPAR was detected on cultured HRPE cells and increased by IL-1. On elongated, live HRPE cells, uPAR dissociated from CD11b (CR3) and translocated to anterior poles of migrating cells. Extracellular proteolysis was concentrated at sites of uPAR expression and specifically inhibited by PAI-1. Cultured HRPE cells secreted substantial, functional collagenase and elastase. IL-1 upregulated uPAR, collagenase, and elastase activities. Specific inhibition of uPAR, and to a lesser degree collagenase, reduced HRPE migration in matrix/gel assays. Immunoreactive uPAR was present along the HRPE basolateral membrane in retinal sections and in sections of diseased retinal tissue. CONCLUSIONS: HRPE cells express functional u

  19. Dexamethasone-Mediated Activation of Fibronectin Matrix Assembly Reduces Dispersal of Primary Human Glioblastoma Cells

    PubMed Central

    Shannon, Stephen; Vaca, Connan; Jia, Dongxuan; Entersz, Ildiko; Schaer, Andrew; Carcione, Jonathan; Weaver, Michael; Avidar, Yoav; Pettit, Ryan; Nair, Mohan; Khan, Atif; Foty, Ramsey A.

    2015-01-01

    Despite resection and adjuvant therapy, the 5-year survival for patients with Glioblastoma multiforme (GBM) is less than 10%. This poor outcome is largely attributed to rapid tumor growth and early dispersal of cells, factors that contribute to a high recurrence rate and poor prognosis. An understanding of the cellular and molecular machinery that drive growth and dispersal is essential if we are to impact long-term survival. Our previous studies utilizing a series of immortalized GBM cell lines established a functional causation between activation of fibronectin matrix assembly (FNMA), increased tumor cohesion, and decreased dispersal. Activation of FNMA was accomplished by treatment with Dexamethasone (Dex), a drug routinely used to treat brain tumor related edema. Here, we utilize a broad range of qualitative and quantitative assays and the use of a human GBM tissue microarray and freshly-isolated primary human GBM cells grown both as conventional 2D cultures and as 3D spheroids to explore the role of Dex and FNMA in modulating various parameters that can significantly influence tumor cell dispersal. We show that the expression and processing of fibronectin in a human GBM tissue-microarray is variable, with 90% of tumors displaying some abnormality or lack in capacity to secrete fibronectin or assemble it into a matrix. We also show that low-passage primary GBM cells vary in their capacity for FNMA and that Dex treatment reactivates this process. Activation of FNMA effectively “glues” cells together and prevents cells from detaching from the primary mass. Dex treatment also significantly increases the strength of cell-ECM adhesion and decreases motility. The combination of increased cohesion and decreased motility discourages in vitro and ex vivo dispersal. By increasing cell-cell cohesion, Dex also decreases growth rate of 3D spheroids. These effects could all be reversed by an inhibitor of FNMA and by the glucocorticoid receptor antagonist, RU-486. Our

  20. Bilayer Membrane Modulation of Membrane Type 1 Matrix Metalloproteinase (MT1-MMP) Structure and Proteolytic Activity.

    PubMed

    Cerofolini, Linda; Amar, Sabrina; Lauer, Janelle L; Martelli, Tommaso; Fragai, Marco; Luchinat, Claudio; Fields, Gregg B

    2016-01-01

    Cell surface proteolysis is an integral yet poorly understood physiological process. The present study has examined how the pericellular collagenase membrane-type 1 matrix metalloproteinase (MT1-MMP) and membrane-mimicking environments interplay in substrate binding and processing. NMR derived structural models indicate that MT1-MMP transiently associates with bicelles and cells through distinct residues in blades III and IV of its hemopexin-like domain, while binding of collagen-like triple-helices occurs within blades I and II of this domain. Examination of simultaneous membrane interaction and triple-helix binding revealed a possible regulation of proteolysis due to steric effects of the membrane. At bicelle concentrations of 1%, enzymatic activity towards triple-helices was increased 1.5-fold. A single mutation in the putative membrane interaction region of MT1-MMP (Ser466Pro) resulted in lower enzyme activation by bicelles. An initial structural framework has thus been developed to define the role(s) of cell membranes in modulating proteolysis. PMID:27405411

  1. Sustained activation of neutrophils in the course of Kawasaki disease: an association with matrix metalloproteinases.

    PubMed

    Biezeveld, M H; van Mierlo, G; Lutter, R; Kuipers, I M; Dekker, T; Hack, C E; Newburger, J W; Kuijpers, T W

    2005-07-01

    Kawasaki disease (KD) is an acute febrile syndrome of childhood, characterized by vasculitis of the medium-sized arteries. White blood cell counts and the inflammatory parameter C-reactive protein (CRP) are known to be elevated in the acute phase of the disease. In this study we investigated the course of inflammatory cell type-specific parameters in KD over a longer period of time. Plasma levels of human neutrophil elastase (HNE), matrix metalloproteinases-2 and -9 (MMP2, MMP9), and neutrophil gelatinase-associated lipocalin (NGAL), macrophage neopterin and CRP were measured. Plasma samples were collected in the acute, subacute and early convalescent stage, and three months after the onset of disease. Median CRP and neopterin normalized within two weeks. In contrast, six weeks and three months after onset of disease, levels of HNE were still elevated, with median values of 163 ng/ml and 156 ng/ml, respectively (control children median < 50 ng/ml; for all time-points P < 0.0001). Values of NGAL correlated with the levels of HNE (r = 0.39, P = 0.013). These results demonstrate a longer state of neutrophil activation in KD than was previously assumed. The potential relationship between this prolonged neutrophil activation, coronary artery lesion formation and their persistence, as well as the risk of premature atherosclerosis warrants further evaluation.

  2. Influence of neutron activation factors on matrix tablets for site specific delivery to the colon.

    PubMed

    Ahrabi, S F; Heinämäki, J; Sande, S A; Graffner, C

    2000-05-01

    The impact of the neutron activation procedure, i.e. incorporation of samarium oxide (Sm(2)O(3)) and neutron irradiation, on the compression properties (including the crushing strength) and in vitro dissolution of potential colonic delivery systems based on matrix tablets of amidated pectin (Am.P) or two types of hydroxypropyl methylcellulose (HPMC) was investigated. The neutron activation factors did not influence the compression properties of the tablets. Replacement of magnesium stearate with samarium stearate in directly compressed Am.P tablets to achieve both radiolabelling and lubrication resulted in a greater extent of concentration-dependent reduction of the crushing strength. Dissolution tests demonstrated that irradiation increased the release of the model drug ropivacaine from the tablets. The extent of this increase was unexpectedly low considering the previously observed degradation of the polymer expressed as an irradiation-induced viscosity reduction in solutions prepared from the polymers. Delayed-release coating with Eudragit L 100 protected the HPMC tablets against the release-increasing effect of irradiation until the late phases of release. Sm(2)O(3) retarded the release to a varying extent depending on particle characteristics. Incorporation of Sm(2)O(3) in the coating layer did not influence the release. However, one-third of the radioactivity leached from the coating within 60 min in 0.1 M HCl. PMID:10767600

  3. Augmented expression of urokinase plasminogen activator and extracellular matrix proteins associates with multiple myeloma progression.

    PubMed

    Khan, Rehan; Gupta, Nidhi; Kumar, Raman; Sharma, Manoj; Kumar, Lalit; Sharma, Alpana

    2014-06-01

    Multiple myeloma (MM) represents a B cell malignancy, characterized by a monoclonal proliferation of malignant plasma cells. Interactions between tumor cells and extracellular matrix (ECM) are of importance for tumor invasion and metastasis. Protein levels of urokinase plasminogen activator (uPA) and fibulin 1, nidogen and laminin in plasma and serum respectively and mRNA levels of these molecules in peripheral blood mononuclear cells were determined in 80 subjects by using ELISA and quantitative PCR and data was analyzed with severity of disease. Pearson correlation was determined to observe interrelationship between different molecules. A statistical significant increase for ECM proteins (laminin, nidogen and fibulin 1) and uPA at circulatory level as well as at mRNA level was observed compared to healthy controls. The levels of these molecules in serum might be utilized as a marker of active disease. Significant positive correlation of all ECM proteins with uPA was found and data also correlates with severity of disease. Strong association found between ECM proteins and uPA in this study supports that there might be interplay between these molecules which can be targeted. This study on these molecules may help to gain insight into processes of growth, spread, and clinical behavior of MM.

  4. Antimicrobial activities of silver used as a polymerization catalyst for a wound-healing matrix

    PubMed Central

    Babu, Ranjith; Zhang, Jianying; Beckman, Eric J.; Virji, Mohammed; Pasculle, William A.; Wells, Alan

    2007-01-01

    Wound healing is a complex and orchestrated process that re-establishes the barrier and other functions of the skin. While wound healing proceeds apace in healthy individual, bacterial overgrowth and infection disrupts this process with significant morbidity and mortality. As such, any artificial matrix to promote wound healing must also control infecting microbes. We had earlier developed a two-part space-conforming gel backbone based on polyethyleneglycol (PEG) or lactose, which used ionic silver as the catalyst for gelation. As silver is widely used as an in vitro antimicrobial, use of silver as a catalyst for gelation provided the opportunity to assess its function as an anti-microbial agent in the gels. We found that these gels show bacteriostatic and bactericidal activity for a range of Gram-negative and Gram-positive organisms, including aerobic as well as anaerobic bacteria. This activity lasted for days, as silver leached out of the formed gels over a day in the manner of second-order decay. Importantly the gels did not limit either cell growth or viability, though cell migration was affected. Adding collagen I fragments to the gels corrected this effect on cell migration. We also found that the PEG gel did not interfere with hemostasis. These observations provide the basis for use of the gel backbones for incorporation of anesthetic agents and factors that promote wound repair. In conclusion, silver ions can serve dual functions of catalyzing gelation and providing anti-microbial properties to a biocompatible polymer. PMID:16635526

  5. Bilayer Membrane Modulation of Membrane Type 1 Matrix Metalloproteinase (MT1-MMP) Structure and Proteolytic Activity

    PubMed Central

    Cerofolini, Linda; Amar, Sabrina; Lauer, Janelle L.; Martelli, Tommaso; Fragai, Marco; Luchinat, Claudio; Fields, Gregg B.

    2016-01-01

    Cell surface proteolysis is an integral yet poorly understood physiological process. The present study has examined how the pericellular collagenase membrane-type 1 matrix metalloproteinase (MT1-MMP) and membrane-mimicking environments interplay in substrate binding and processing. NMR derived structural models indicate that MT1-MMP transiently associates with bicelles and cells through distinct residues in blades III and IV of its hemopexin-like domain, while binding of collagen-like triple-helices occurs within blades I and II of this domain. Examination of simultaneous membrane interaction and triple-helix binding revealed a possible regulation of proteolysis due to steric effects of the membrane. At bicelle concentrations of 1%, enzymatic activity towards triple-helices was increased 1.5-fold. A single mutation in the putative membrane interaction region of MT1-MMP (Ser466Pro) resulted in lower enzyme activation by bicelles. An initial structural framework has thus been developed to define the role(s) of cell membranes in modulating proteolysis. PMID:27405411

  6. A genetic fiber modification to achieve matrix-metalloprotease-activated infectivity of oncolytic adenovirus.

    PubMed

    José, Anabel; Rovira-Rigau, Maria; Luna, Jeroni; Giménez-Alejandre, Marta; Vaquero, Eva; García de la Torre, Beatriz; Andreu, David; Alemany, Ramon; Fillat, Cristina

    2014-10-28

    Selective tumor targeting of oncolytic adenovirus at the level of cell entry remains a major challenge to improve efficacy and safety. Matrix metalloproteases (MMPs) are overexpressed in a variety of tumors and in particular in pancreatic cancer. In the current work, we have exploited the expression of MMPs together with the penetration capabilities of a TAT-like peptide to engineer tumor selective adenoviruses. We have generated adenoviruses containing CAR-binding ablated fibers further modified with a C-terminus TAT-like peptide linked to a blocking domain by an MMP-cleavable sequence. This linker resulted in a MMP-dependent cell transduction of the reporter MMP-activatable virus AdTATMMP and in efficient transduction of neoplastic cells and cancer-associated fibroblasts. Intravenous and intraductal administration of AdTATMMP into mice showed very low AdTATMMP activity in the normal pancreas, whereas increased transduction was observed in pancreatic tumors of transgenic Ela-myc mice. Intraductal administration of AdTATMMP into mice bearing orthotopic tumors led to a 25-fold increase in tumor targeting compared to the wild type fiber control. A replication competent adenovirus, Ad(RC)MMP, with the MMP-activatable fiber showed oncolytic efficacy and increased antitumor activity compared to Adwt in a pancreatic orthotopic model. Reduced local and distant metastases were observed in Ad(RC)MMP treated-mice. Moreover, no signs of pancreatic toxicity were detected. We conclude that MMP-activatable adenovirus may be beneficial for pancreatic cancer treatment.

  7. Withaferin A inhibits matrix metalloproteinase-9 activity by suppressing the Akt signaling pathway.

    PubMed

    Lee, Dae Hyung; Lim, In-Hye; Sung, Eon-Gi; Kim, Joo-Young; Song, In-Hwan; Park, Yoon Ki; Lee, Tae-Jin

    2013-08-01

    Withaferin A (Wit A), a steroidal lactone isolated from Withania somnifera, exhibits anti-inflammatory, immuno-modulatory and anti-angiogenic properties and antitumor activities. In the present study, we investigated the effects of Wit A on protease-mediated invasiveness of the human metastatic cancer cell lines Caski and SK-Hep1. We found that treatment with Wit A resulted in marked inhibition of the TGF‑β‑induced increase in expression and activity of matrix metalloproteinase (MMP)‑9 in Caski cell line. These effects of Wit A were dose-dependent and showed a correlation with suppression of MMP‑9 mRNA expression levels. Treatment with Wit A resulted in an ~1.6-fold induction of MMP-9 promoter activity, which was also suppressed by treatment with Wit A in Caski cells. We found that treatment with Wit A resulted in inhibition of TGF‑β‑induced phosphorylation of Akt, which was involved in the downregulation of expression of MMP-9 at the protein level. Introduction with constitutively active (CA)‑Akt resulted in a partial increase in the secretion of TGF-β-induced MMP-9 blocked by treatment with Wit A in Caski cells. According to these results, Wit A may inhibit the invasive and migratory abilities of Caski cells through a reduction in MMP-9 expression through suppression of the pAkt signaling pathway. These findings indicate that use of Wit A may be an effective strategy for control of metastasis and invasiveness of tumors.

  8. Acrolein activates matrix metalloproteinases by increasing reactive oxygen species in macrophages

    SciTech Connect

    O'Toole, Timothy E. Zheng Yuting; Hellmann, Jason; Conklin, Daniel J.; Barski, Oleg; Bhatnagar, Aruni

    2009-04-15

    Acrolein is a ubiquitous component of environmental pollutants such as automobile exhaust, cigarette, wood, and coal smoke. It is also a natural constituent of several foods and is generated endogenously during inflammation or oxidation of unsaturated lipids. Because increased inflammation and episodic exposure to acrolein-rich pollutants such as traffic emissions or cigarette smoke have been linked to acute myocardial infarction, we examined the effects of acrolein on matrix metalloproteinases (MMPs), which destabilize atherosclerotic plaques. Our studies show that exposure to acrolein resulted in the secretion of MMP-9 from differentiated THP-1 macrophages. Acrolein-treatment of macrophages also led to an increase in reactive oxygen species (ROS), free intracellular calcium ([Ca{sup 2+}]{sub i}), and xanthine oxidase (XO) activity. ROS production was prevented by allopurinol, but not by rotenone or apocynin and by buffering changes in [Ca{sup 2+}]{sub I} with BAPTA-AM. The increase in MMP production was abolished by pre-treatment with the antioxidants Tiron and N-acetyl cysteine (NAC) or with the xanthine oxidase inhibitors allopurinol or oxypurinol. Finally, MMP activity was significantly stimulated in aortic sections from apoE-null mice containing advanced atherosclerotic lesions after exposure to acrolein ex vivo. These observations suggest that acrolein exposure results in MMP secretion from macrophages via a mechanism that involves an increase in [Ca{sup 2+}]{sub I}, leading to xanthine oxidase activation and an increase in ROS production. ROS-dependent activation of MMPs by acrolein could destabilize atherosclerotic lesions during brief episodes of inflammation or pollutant exposure.

  9. Sync Matrix

    2004-12-31

    Sync Matrix provides a graphic display of the relationships among all of the response activities of each jurisdiction. This is accomplished through software that organizes and displays the activities by jurisdiction, function, and time for easy review and analysis. The software can also integrate the displays of multiple jurisdictions to allow examination of the total response.

  10. Atmospheric-Pressure Cold Plasmas Used to Embed Bioactive Compounds in Matrix Material for Active Packaging of Fruits and Vegetables

    NASA Astrophysics Data System (ADS)

    Fernandez, Sulmer; Pedrow, Patrick; Powers, Joseph; Pitts, Marvin

    2009-10-01

    Active thin film packaging is a technology with the potential to provide consumers with new fruit and vegetable products-if the film can be applied without deactivating bioactive compounds.Atmospheric pressure cold plasma (APCP) processing can be used to activate monomer with concomitant deposition of an organic plasma polymerized matrix material and to immobilize a bioactive compound all at or below room temperature.Aims of this work include: 1) immobilize an antimicrobial in the matrix; 2) determine if the antimicrobial retains its functionality and 3) optimize the reactor design.The plasma zone will be obtained by increasing the voltage on an electrode structure until the electric field in the feed material (argon + monomer) yields electron avalanches. Results will be described using Red Delicious apples.Prospective matrix precursors are vanillin and cinnamic acid.A prospective bioactive compound is benzoic acid.

  11. Airway mucus obstruction triggers macrophage activation and matrix metalloproteinase 12-dependent emphysema.

    PubMed

    Trojanek, Joanna B; Cobos-Correa, Amanda; Diemer, Stefanie; Kormann, Michael; Schubert, Susanne C; Zhou-Suckow, Zhe; Agrawal, Raman; Duerr, Julia; Wagner, Claudius J; Schatterny, Jolanthe; Hirtz, Stephanie; Sommerburg, Olaf; Hartl, Dominik; Schultz, Carsten; Mall, Marcus A

    2014-11-01

    Whereas cigarette smoking remains the main risk factor for emphysema, recent studies in β-epithelial Na(+) channel-transgenic (βENaC-Tg) mice demonstrated that airway surface dehydration, a key pathophysiological mechanism in cystic fibrosis (CF), caused emphysema in the absence of cigarette smoke exposure. However, the underlying mechanisms remain unknown. The aim of this study was to elucidate mechanisms of emphysema formation triggered by airway surface dehydration. We therefore used expression profiling, genetic and pharmacological inhibition, Foerster resonance energy transfer (FRET)-based activity assays, and genetic association studies to identify and validate emphysema candidate genes in βENaC-Tg mice and patients with CF. We identified matrix metalloproteinase 12 (Mmp12) as a highly up-regulated gene in lungs from βENaC-Tg mice, and demonstrate that elevated Mmp12 expression was associated with progressive emphysema formation, which was reduced by genetic deletion and pharmacological inhibition of MMP12 in vivo. By using FRET reporters, we show that MMP12 activity was elevated on the surface of airway macrophages in bronchoalveolar lavage from βENaC-Tg mice and patients with CF. Furthermore, we demonstrate that a functional polymorphism in MMP12 (rs2276109) was associated with severity of lung disease in CF. Our results suggest that MMP12 released by macrophages activated on dehydrated airway surfaces may play an important role in emphysema formation in the absence of cigarette smoke exposure, and may serve as a therapeutic target in CF and potentially other chronic lung diseases associated with airway mucus dehydration and obstruction. PMID:24828142

  12. Single-pixel polarimetric imaging.

    PubMed

    Durán, Vicente; Clemente, Pere; Fernández-Alonso, Mercedes; Tajahuerce, Enrique; Lancis, Jesús

    2012-03-01

    We present an optical system that performs Stokes polarimetric imaging with a single-pixel detector. This fact is possible by applying the theory of compressive sampling to the data acquired by a commercial polarimeter without spatial resolution. The measurement process is governed by a spatial light modulator, which sequentially generates a set of preprogrammed light intensity patterns. Experimental results are presented and discussed for an object that provides an inhomogeneous polarization distribution. PMID:22378406

  13. Representing SAR complex image pixels

    NASA Astrophysics Data System (ADS)

    Doerry, A. W.

    2016-05-01

    Synthetic Aperture Radar (SAR) images are often complex-valued to facilitate specific exploitation modes. Furthermore, these pixel values are typically represented with either real/imaginary (also known as I/Q) values, or as Magnitude/Phase values, with constituent components comprised of integers with limited number of bits. For clutter energy well below full-scale, Magnitude/Phase offers lower quantization noise than I/Q representation. Further improvement can be had with companding of the Magnitude value.

  14. SAR Image Complex Pixel Representations

    SciTech Connect

    Doerry, Armin W.

    2015-03-01

    Complex pixel values for Synthetic Aperture Radar (SAR) images of uniform distributed clutter can be represented as either real/imaginary (also known as I/Q) values, or as Magnitude/Phase values. Generally, these component values are integers with limited number of bits. For clutter energy well below full-scale, Magnitude/Phase offers lower quantization noise than I/Q representation. Further improvement can be had with companding of the Magnitude value.

  15. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Seshadri, Suresh (Inventor); Cole, David (Inventor); Smith, Roger M (Inventor); Hancock, Bruce R. (Inventor)

    2013-01-01

    The effects of inter pixel capacitance in a pixilated array may be measured by first resetting all pixels in the array to a first voltage, where a first image is read out, followed by resetting only a subset of pixels in the array to a second voltage, where a second image is read out, where the difference in the first and second images provide information about the inter pixel capacitance. Other embodiments are described and claimed.

  16. Piezoelectric properties of the new generation active matrix hybrid (micro-nano) composites

    NASA Astrophysics Data System (ADS)

    Parali, Levent; Şabikoğlu, İsrafil; Kurbanov, Mirza A.

    2014-11-01

    A hybrid piezoelectric composite structure is obtained by addition of nano-sized BaTiO3, SiO2 to the micro-sized PZT and polymers composition. Although the PZT material itself has excellent piezoelectric properties, PZT-based composite variety is limited. Piezoelectric properties of PZT materials can be varied with an acceptor or a donor added to the material. In addition, varieties of PZT-based sensors can be increased with doping polymers which have physical-mechanical, electrophysical, thermophysical and photoelectrical properties. The active matrix hybrid structure occurs when bringing together the unique piezoelectric properties of micro-sized PZT with electron trapping properties of nano-sized insulators (BaTiO3 or SiO2), and their piezoelectric, mechanic and electromechanic properties significantly change. In this study, the relationship between the piezoelectric constant and the coupling factor values of microstructure (PZT-PVDF) and the hybrid structure (PZT-PVDF-BaTiO3) composite are compared. The d33 value and the coupling factor of the hybrid structure have shown an average of 54 and 62% increase according to microstructure composite, respectively. In addition, the d33 value and the coupling factor of the hybrid structure (PZT-HDPE-SiO2) have exhibited about 68 and 52% increase according to microstructure composite (PZT-HDPE), respectively.

  17. Stretchable active-matrix organic light-emitting diode display using printable elastic conductors

    NASA Astrophysics Data System (ADS)

    Sekitani, Tsuyoshi; Nakajima, Hiroyoshi; Maeda, Hiroki; Fukushima, Takanori; Aida, Takuzo; Hata, Kenji; Someya, Takao

    2009-06-01

    Stretchability will significantly expand the applications scope of electronics, particularly for large-area electronic displays, sensors and actuators. Unlike for conventional devices, stretchable electronics can cover arbitrary surfaces and movable parts. However, a large hurdle is the manufacture of large-area highly stretchable electrical wirings with high conductivity. Here, we describe the manufacture of printable elastic conductors comprising single-walled carbon nanotubes (SWNTs) uniformly dispersed in a fluorinated rubber. Using an ionic liquid and jet-milling, we produce long and fine SWNT bundles that can form well-developed conducting networks in the rubber. Conductivity of more than 100Scm-1 and stretchability of more than 100% are obtained. Making full use of this extraordinary conductivity, we constructed a rubber-like stretchable active-matrix display comprising integrated printed elastic conductors, organic transistors and organic light-emitting diodes. The display could be stretched by 30-50% and spread over a hemisphere without any mechanical or electrical damage.

  18. Active matrix organic light emitting diode (OLED)-XL life test results

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Wood, Michael V.; Hastings, Arthur R., Jr.; Ghosh, Amalkumar P.; Prache, Olivier

    2008-04-01

    OLED displays have been known to exhibit high levels of performance with regards to contrast, response time, uniformity, and viewing angle, but a lifetime improvement has been perceived to be essential for broadening the applications of OLED's in the military and in the commercial market. As a result of this need, the US Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to improve the lifetime of OLED displays. In 2006, eMagin Corporation developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications, and RDECOM CERDEC NVESD ran life tests on these displays, finding over 200% lifetime improvement for the XL devices over the standard displays. Early results were published at the 2007 SPIE Defense and Security Symposium. Further life testing of XL and standard devices at ambient conditions and at high temperatures will be presented this year along with a recap of previous data. This should result in a better understanding of the applicability of AMOLEDs in military and commercial head mounted systems: where good fits are made, and where further development might be needed. This is a continuation of the paper "Life test results of OLED-XL long-life devices for use in active matrix organic light emitting diode (AMOLED) displays for head mounted applications" presented at SPIE DSS in 2007.

  19. Trivalent metal ions based on inorganic compounds with in vitro inhibitory activity of matrix metalloproteinase 13.

    PubMed

    Wen, Hanyu; Qin, Yuan; Zhong, Weilong; Li, Cong; Liu, Xiang; Shen, Yehua

    2016-10-01

    Collagenase-3 (MMP-13) inhibitors have attracted considerable attention in recent years and have been developed as a therapeutic target for a variety of diseases, including cancer. Matrix metalloproteinases (MMPs) can be inhibited by a multitude of compounds, including hydroxamic acids. Studies have shown that materials and compounds containing trivalent metal ions, particularly potassium hexacyanoferrate (III) (K3[Fe(CN)6]), exhibit cdMMP-13 inhibitory potential with a half maximal inhibitory concentration (IC50) of 1.3μM. The target protein was obtained by refolding the recombinant histidine-tagged cdMMP-13 using size exclusion chromatography (SEC). The secondary structures of the refolded cdMMP-13 with or without metal ions were further analyzed via circular dichroism and the results indicate that upon binding with metal ions, an altered structure with increased domain stability was obtained. Furthermore, isothermal titration calorimetry (ITC) experiments demonstrated that K3[Fe(CN)6]is able to bind to MMP-13 and endothelial cell tube formation tests provide further evidence for this interaction to exhibit anti-angiogenesis potential. To the best of our knowledge, no previous report of an inorganic compound featuring a MMP-13 inhibitory activity has ever been reported in the literature. Our results demonstrate that K3[Fe(CN)6] is useful as a new effective and specific inhibitor for cdMMP-13 which may be of great potential for future drug screening applications. PMID:27542739

  20. Estimating nonnegative matrix model activations with deep neural networks to increase perceptual speech quality.

    PubMed

    Williamson, Donald S; Wang, Yuxuan; Wang, DeLiang

    2015-09-01

    As a means of speech separation, time-frequency masking applies a gain function to the time-frequency representation of noisy speech. On the other hand, nonnegative matrix factorization (NMF) addresses separation by linearly combining basis vectors from speech and noise models to approximate noisy speech. This paper presents an approach for improving the perceptual quality of speech separated from background noise at low signal-to-noise ratios. An ideal ratio mask is estimated, which separates speech from noise with reasonable sound quality. A deep neural network then approximates clean speech by estimating activation weights from the ratio-masked speech, where the weights linearly combine elements from a NMF speech model. Systematic comparisons using objective metrics, including the perceptual evaluation of speech quality, show that the proposed algorithm achieves higher speech quality than related masking and NMF methods. In addition, a listening test was performed and its results show that the output of the proposed algorithm is preferred over the comparison systems in terms of speech quality. PMID:26428778

  1. Probing matrix and tumor mechanics with in situ calibrated optical trap based active microrheology

    NASA Astrophysics Data System (ADS)

    Staunton, Jack Rory; Vieira, Wilfred; Tanner, Kandice; Tissue Morphodynamics Unit Team

    Aberrant extracellular matrix deposition and vascularization, concomitant with proliferation and phenotypic changes undergone by cancer cells, alter mechanical properties in the tumor microenvironment during cancer progression. Tumor mechanics conversely influence progression, and the identification of physical biomarkers promise improved diagnostic and prognostic power. Optical trap based active microrheology enables measurement of forces up to 0.5 mm within a sample, allowing interrogation of in vitro biomaterials, ex vivo tissue sections, and small organisms in vivo. We fabricated collagen I hydrogels exhibiting distinct structural properties by tuning polymerization temperature Tp, and measured their shear storage and loss moduli at frequencies 1-15k Hz at multiple amplitudes. Lower Tp gels, with larger pore size but thicker, longer fibers, were stiffer than higher Tp gels; decreasing strain increased loss moduli and decreased storage moduli at low frequencies. We subcutanously injected probes with metastatic murine melanoma cells into mice. The excised tumors displayed storage and loss moduli 40 Pa and 10 Pa at 1 Hz, increasing to 500 Pa and 1 kPa at 15 kHz, respectively.

  2. Alternatives to low-temperature poly-Si technology in active matrix displays

    NASA Astrophysics Data System (ADS)

    Flores, James S.

    2001-04-01

    Incorporating low temperature poly-Si (LTPS) technology as an active matrix (AM) in flat panel displays (FPDs) has been a struggle and remains costly. The situation motivates companies to investigate alternative AM technologies. Some projects try to relieve the low temperature constraint by switching the substrate material to a metal foil. Some companies try simply to make the most out of a-Si:H technology. Another strategy is to replace silicons as the TFT channel material. Examples include CdSe and even an organic material like pentacene. When crystalline silicon is considered best, engineers consider how to replace excimer laser annealing (ELA) and its cost. A prominent example is the effort at MIT, which printed devices with a kind of 'semiconductor ink'. The best prospects for inexpensive AM backplanes may be plastic transistors and c-Si block assembly. Current leaders of AM technology, a-Si:H and ELA- LTPS, might still end up offering better overall performance, but their costs will probably be higher.

  3. Biosensing of matrix metalloproteinase activity with Cd-free quantum dots

    NASA Astrophysics Data System (ADS)

    Plumley, John Bryan

    Quantum dots (QDs) have become attractive in the biomedical field on account of their superior optical properties and stability, in comparison to traditional fluorophores. QDs also have properties which make them ideal for complex in vivo conditions. However, toxicity has been a chief concern in the eventual implementation of QDs for in vivo applications such as biosensing and tumor imaging. Commercially available QDs contain a notoriously noxious Cd component and therefore continuous research has gone into developing QDs without toxic heavy metals, generally Cd, that would still yield comparable performance in terms of their optical properties. Nonetheless, even in the case of Cd-free QDs, toxicity should be evaluated on a case by case basis, as other properties such as size, coating, stability, and charge can affect toxicity of nanomaterials as well, making it a very complex issue. With the high promise of QDs in the field of biomedical development as a motivation, this work strives to develop the efficient and repeatable synthesis of Cd-free QDs with high stability and luminescence, with proven low toxicity, and the ability to detect active matrix metalloproteinase (MMP) in a biosensing system, designed to identify direct biomarkers for pathological conditions, which in turn would enable early disease diagnosis and better treatment development. In this work, highly luminescent ZnSe:Mn/ZnS QDs have been synthesized, characterized, and modified with peptides with a bioconjugation procedure that utilized thiol-metal affinity. Experiments aiming at MMP detection were conducted using the peptide/QD conjugates. In addition, the ApoTox-Glo(TM) Triplex assay was utilized to evaluate cytotoxicity, and a safe concentration below 0.125 microM was identified for peptide-coated ZnSe:Mn/ZnS QDs in water. Finally, in contribution to developing an in vivo fiberoptic system for sensing MMP activity, the QDs were successfully tethered to silica and MMP detection was demonstrated

  4. Development and characterization of the latest X-ray SOI pixel sensor for a future astronomical mission

    NASA Astrophysics Data System (ADS)

    Nakashima, Shinya; Gando Ryu, Syukyo; Tanaka, Takaaki; Go Tsuru, Takeshi; Takeda, Ayaki; Arai, Yasuo; Imamura, Toshifumi; Ohmoto, Takafumi; Iwata, Atsushi

    2013-12-01

    We have been developing active pixel sensors based on silicon-on-insulator technology for future X-ray astronomy missions. Recently we fabricated the new prototype named “XRPIX2”, and investigated its spectroscopic performance. For comparison and evaluation of different chip designs, XRPIX2 consists of 3 pixel types: Small Pixel, Large Pixel 1, and Large Pixel 2. In Small Pixel, we found that the gains of the 68% pixels are within 1.4% of the mean value, and the energy resolution is 656 eV (FWHM) for 8 keV X-rays, which is the best spectroscopic performance in our development. The pixel pitch of Large Pixel 1 and Large Pixel 2 is twice as large as that of Small Pixel. Charge sharing events are successfully reduced for Large Pixel 1. Moreover Large Pixel 2 has multiple nodes for charge collection in a pixel. We confirmed that the multi-nodes structure is effective to increase charge collection efficiency.

  5. Perineuronal nets of extracellular matrix around hippocampal interneurons resist destruction by activated microglia in trimethyltin-treated rats.

    PubMed

    Schüppel, Karin; Brauer, Kurt; Härtig, Wolfgang; Grosche, Jens; Earley, Bernadette; Leonard, Brian E; Brückner, Gert

    2002-12-27

    The destruction of the extracellular matrix by inflammatory processes may induce neuronal dysfunction and accelerate neurodegeneration. We describe that chondroitin sulphate proteoglycan-immunoreactive perineuronal nets and the enwrapped interneurons persisted 2 weeks after trimethyltin intoxication of rats (TMT, 8 mg/kg, i.p.) in all regions of the severely affected hippocampus and dentate gyrus, whereas the diffuse immunoreactivity around the CA2 pyramidal cells was reduced. Fluoro-Jade staining of degenerating neurons and staining of microglia by Griffonia simplicifolia agglutinin showed that net-associated neurons survived in the vicinity of damaged pyramidal cells and that perineuronal nets were not removed by activated microglia. We conclude that the extracellular matrix of perineuronal nets resists destruction after TMT treatment in the inflamed neural tissue. A permanent reconstitution of matrix components may be one of the factors that may support the viability of distinct types of neurons during neurodegenerative diseases.

  6. Design and TCAD simulation of planar p-on-n active-edge pixel sensors for the next generation of FELs

    NASA Astrophysics Data System (ADS)

    Dalla Betta, G.-F.; Batignani, G.; Benkechkache, M. A.; Bettarini, S.; Casarosa, G.; Comotti, D.; Fabris, L.; Forti, F.; Grassi, M.; Latreche, S.; Lodola, L.; Malcovati, P.; Manghisoni, M.; Mendicino, R.; Morsani, F.; Paladino, A.; Pancheri, L.; Paoloni, E.; Ratti, L.; Re, V.; Rizzo, G.; Traversi, G.; Vacchi, C.; Verzellesi, G.; Xu, H.

    2016-07-01

    We report on the design and TCAD simulations of planar p-on-n sensors with active edge aimed at a four-side buttable X-ray detector module for future FEL applications. Edge terminations with different number of guard rings were designed to find the best trade-off between breakdown voltage and border gap size. The methodology of the sensor design, the optimization of the most relevant parameters to maximize the breakdown voltage and the final layout are described.

  7. Determination of fission neutron transmission through waste matrix material using neutron signal correlation from active assay of {sup 239}Pu

    SciTech Connect

    Hollas, C.L.; Arnone, G.; Brunson, G.; Coop, K.

    1996-09-01

    The accuracy of TRU (transuranic) waste assay using the differential die-away technique depends upon significant corrections to compensate for the effects of the matrix material in which the TRU waste is located. The authors have used a new instrument, the Combined Thermal/Epithermal Neutron (CTEN) instrument for the assay of TRU waste, to develop methods to improve the accuracy of these corrections. Neutrons from a pulsed 14-MeV neutron generator are moderated in the walls of the CTEN cavity and induce fission in the TRU material. The prompt neutrons from these fission events are detected in cadmium-wrapped {sup 3}He neutron detectors. They report new methods of data acquisition and analysis to extract correlation in the neutron signals resulting form fission during active interrogation. They use the correlation information in conjunction with the total number of neutrons to determine the fraction of fission neutrons transmitted through the matrix material into the {sup 3}He detectors. This determination allows them to cleanly separate the matrix effects into two processes: matrix modification upon the neutron interrogating flux and matrix modification upon the fraction of fission neutrons transmitted to the neutron detectors. This transmission information is also directly applied in a neutron multiplicity analysis in the passive assay of {sup 240}Pu.

  8. Active matrix organic light emitting diode (AMOLED) performance and life test results

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Botkin, Michael E.; Draper, Russell S.; Coletta, Jason

    2013-05-01

    The U.S. Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to characterize the ongoing improvements in the lifetime of OLED displays. This CRADA also called for the evaluation of OLED performance as the need arises, especially when new products are developed or when a previously untested parameter needs to be understood. In 2006, eMagin Corporation developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications. Through Research and Development programs from 2007 to 2012 with the U.S. Government, eMagin made additional improvements in OLED life and developed the first SXGA (1280 X 1024 with triad pixels) and WUXGA (1920 X 1200 with triad pixels) OLED microdisplays. US Army RDECOM CERDEC NVESD conducted life and performance tests on these displays, publishing results at the 2012, 2011, 2010, 2009, 2008, and 2007 SPIE Defense, Security and Sensing Symposia. Life and performance tests have continued through 2013, and this data will be presented along with a comparison to previous data. This should result in a better understanding of the applicability of AMOLEDs in military and commercial head mounted systems, where good fits are made, and where further development might be desirable.

  9. Proanthocyanidins from the American Cranberry (Vaccinium macrocarpon) inhibit matrix metalloproteinase-2 and matrix metalloproteinase-9 activity in human prostate cancer cells via alterations in multiple cellular signalling pathways.

    PubMed

    Déziel, Bob A; Patel, Kunal; Neto, Catherine; Gottschall-Pass, Katherine; Hurta, Robert A R

    2010-10-15

    Prostate cancer is one of the most common cancers in the Western world, and it is believed that an individual's diet affects his risk of developing cancer. There has been an interest in examining phytochemicals, the secondary metabolites of plants, in order to determine their potential anti-cancer activities in vitro and in vivo. In this study we document the effects of proanthocyanidins (PACs) from the American Cranberry (Vaccinium macrocarpon) on matrix metalloproteinase (MMP) activity in DU145 human prostate cancer cells. Cranberry PACs decreased cellular viability of DU145 cells at a concentration of 25 µg/ml by 30% after 6 h of treatment. Treatment of DU145 cells with PACs resulted in an inhibition of both MMPs 2 and 9 activity. PACs increased the expression of TIMP-2, a known inhibitor of MMP activity, and decreased the expression of EMMPRIN, an inducer of MMP expression. PACs decreased the expression of PI-3 kinase and AKT proteins, and increased the phosphorylation of both p38 and ERK1/2. Cranberry PACs also decreased the translocation of the NF-κB p65 protein to the nucleus. Cranberry PACs increased c-jun and decreased c-fos protein levels. These results suggest that cranberry PACs decreases MMP activity through the induction and/or inhibition of specific temporal MMP regulators, and by affecting either the phosphorylation status and/or expression of MAP kinase, PI-3 kinase, NF-κB and AP-1 pathway proteins. This study further demonstrates that cranberry PACs are a strong candidate for further research as novel anti-cancer agents.

  10. Expression and activation of matrix metalloproteinases in wounds: modulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+.

    PubMed

    Siméon, A; Monier, F; Emonard, H; Gillery, P; Birembaut, P; Hornebeck, W; Maquart, F X

    1999-06-01

    We investigated the expression and activation of matrix metalloproteinases in a model of experimental wounds in rats, and their modulation by glycyl-L-histidyl-L-lysine-Cu(II), a potent activator of wound repair. Wound chambers were inserted under the skin of Sprague-Dawley rats and received serial injections of either 2 mg glycyl-L-histidyl-L-lysine-Cu(II) or the same volume of saline. The wound fluid and the neosynthetized connective tissue deposited in the chambers were collected and analyzed for matrix metalloproteinase expression and/or activity. Interstitial collagenase increased progressively in the wound fluid throughout the experiment. Glycyl-L-histidyl-L-lysine-Cu(II) treatment did not alter its activity. Matrix metalloproteinase-9 (gelatinase B) and matrix metalloproteinase-2 (gelatinase A) were the two main gelatinolytic activities expressed during the healing process. Pro-matrix metalloproteinase (pro-form of matrix metalloproteinase)-9 was strongly expressed during the early stages of wound healing (day 3). In the wound fluid, it decreased rapidly and disappeared after day 18, whereas in the wound tissue, matrix metalloproteinase-9 expression persisted in the glycyl-L-histidyl-L-lysine-Cu(II) injected chamber until day 22. Pro-matrix metalloproteinase-2 was expressed at low levels at the beginning of the healing process, increased progressively until day 7, then decreased until day 18. Activated matrix metalloproteinase-2 was present in wound fluid and wound tissue. It increased until day 12, then decreased progressively. Glycyl-L-histidyl-L-lysine-Cu(II) injections increased pro-matrix metalloproteinase-2 and activated matrix metalloproteinase-2 during the later stages of healing (days 18 and/or 22). These results demonstrate that various types of matrix metalloproteinases are selectively expressed or activated at the various periods of wound healing. Glycyl-L-histidyl-L-lysine-Cu(II) is able to modulate their expression and might significantly alter

  11. Flax Fiber Hydrophobic Extract Inhibits Human Skin Cells Inflammation and Causes Remodeling of Extracellular Matrix and Wound Closure Activation

    PubMed Central

    Styrczewska, Monika; Kostyn, Anna; Kulma, Anna; Majkowska-Skrobek, Grazyna; Augustyniak, Daria; Prescha, Anna; Czuj, Tadeusz; Szopa, Jan

    2015-01-01

    Inflammation is the basis of many diseases, with chronic wounds amongst them, limiting cell proliferation and tissue regeneration. Our previous preclinical study of flax fiber applied as a wound dressing and analysis of its components impact on the fibroblast transcriptome suggested flax fiber hydrophobic extract use as an anti-inflammatory and wound healing preparation. The extract contains cannabidiol (CBD), phytosterols, and unsaturated fatty acids, showing great promise in wound healing. In in vitro proliferation and wound closure tests the extract activated cell migration and proliferation. The activity of matrix metalloproteinases in skin cells was increased, suggesting activation of extracellular components remodeling. The expression of cytokines was diminished by the extract in a cannabidiol-dependent manner, but β-sitosterol can act synergistically with CBD in inflammation inhibition. Extracellular matrix related genes were also analyzed, considering their importance in further stages of wound healing. The extract activated skin cell matrix remodeling, but the changes were only partially cannabidiol- and β-sitosterol-dependent. The possible role of fatty acids also present in the extract is suggested. The study shows the hydrophobic flax fiber components as wound healing activators, with anti-inflammatory cannabidiol acting in synergy with sterols, and migration and proliferation promoting agents, some of which still require experimental identification. PMID:26347154

  12. Flax Fiber Hydrophobic Extract Inhibits Human Skin Cells Inflammation and Causes Remodeling of Extracellular Matrix and Wound Closure Activation.

    PubMed

    Styrczewska, Monika; Kostyn, Anna; Kulma, Anna; Majkowska-Skrobek, Grazyna; Augustyniak, Daria; Prescha, Anna; Czuj, Tadeusz; Szopa, Jan

    2015-01-01

    Inflammation is the basis of many diseases, with chronic wounds amongst them, limiting cell proliferation and tissue regeneration. Our previous preclinical study of flax fiber applied as a wound dressing and analysis of its components impact on the fibroblast transcriptome suggested flax fiber hydrophobic extract use as an anti-inflammatory and wound healing preparation. The extract contains cannabidiol (CBD), phytosterols, and unsaturated fatty acids, showing great promise in wound healing. In in vitro proliferation and wound closure tests the extract activated cell migration and proliferation. The activity of matrix metalloproteinases in skin cells was increased, suggesting activation of extracellular components remodeling. The expression of cytokines was diminished by the extract in a cannabidiol-dependent manner, but β-sitosterol can act synergistically with CBD in inflammation inhibition. Extracellular matrix related genes were also analyzed, considering their importance in further stages of wound healing. The extract activated skin cell matrix remodeling, but the changes were only partially cannabidiol- and β-sitosterol-dependent. The possible role of fatty acids also present in the extract is suggested. The study shows the hydrophobic flax fiber components as wound healing activators, with anti-inflammatory cannabidiol acting in synergy with sterols, and migration and proliferation promoting agents, some of which still require experimental identification. PMID:26347154

  13. Flax Fiber Hydrophobic Extract Inhibits Human Skin Cells Inflammation and Causes Remodeling of Extracellular Matrix and Wound Closure Activation.

    PubMed

    Styrczewska, Monika; Kostyn, Anna; Kulma, Anna; Majkowska-Skrobek, Grazyna; Augustyniak, Daria; Prescha, Anna; Czuj, Tadeusz; Szopa, Jan

    2015-01-01

    Inflammation is the basis of many diseases, with chronic wounds amongst them, limiting cell proliferation and tissue regeneration. Our previous preclinical study of flax fiber applied as a wound dressing and analysis of its components impact on the fibroblast transcriptome suggested flax fiber hydrophobic extract use as an anti-inflammatory and wound healing preparation. The extract contains cannabidiol (CBD), phytosterols, and unsaturated fatty acids, showing great promise in wound healing. In in vitro proliferation and wound closure tests the extract activated cell migration and proliferation. The activity of matrix metalloproteinases in skin cells was increased, suggesting activation of extracellular components remodeling. The expression of cytokines was diminished by the extract in a cannabidiol-dependent manner, but β-sitosterol can act synergistically with CBD in inflammation inhibition. Extracellular matrix related genes were also analyzed, considering their importance in further stages of wound healing. The extract activated skin cell matrix remodeling, but the changes were only partially cannabidiol- and β-sitosterol-dependent. The possible role of fatty acids also present in the extract is suggested. The study shows the hydrophobic flax fiber components as wound healing activators, with anti-inflammatory cannabidiol acting in synergy with sterols, and migration and proliferation promoting agents, some of which still require experimental identification.

  14. Food matrix and processing influence on carotenoid bioaccessibility and lipophilic antioxidant activity of fruit juice-based beverages.

    PubMed

    Rodríguez-Roque, María Janeth; de Ancos, Begoña; Sánchez-Vega, Rogelio; Sánchez-Moreno, Concepción; Cano, M Pilar; Elez-Martínez, Pedro; Martín-Belloso, Olga

    2016-01-01

    The biological activity of carotenoids depends on their bioaccessibility and solubilization in the gastrointestinal tract. These compounds are poorly dispersed in the aqueous media of the digestive tract due to their lipophilic nature. Thus, it is important to analyze the extent to which some factors, such as the food matrix and food processing, may improve their bioaccessibility. Beverages formulated with a blend of fruit juices and water (WB), milk (MB) or soymilk (SB) were treated by high-intensity pulsed electric fields (HIPEF) (35 kV cm(-1) with 4 μs bipolar pulses at 200 Hz for 1800 μs), high-pressure processing (HPP) (400 MPa at 40 °C for 5 min) or thermal treatment (TT) (90 °C for 1 min) in order to evaluate the influence of food matrix and processing on the bioaccessibility of carotenoids and on the lipophilic antioxidant activity (LAA). The bioaccessibility of these compounds diminished after applying any treatment (HIPEF, HPP and TT), with the exception of cis-violaxanthin + neoxanthin, which increased by 79% in HIPEF and HPP beverages. The lowest carotenoid bioaccessibility was always obtained in TT beverages (losses up to 63%). MB was the best food matrix for improving the bioaccessibility of carotenoids, as well as the LAA. The results demonstrate that treatment and food matrix modulated the bioaccessibility of carotenoids as well as the lipophilic antioxidant potential of beverages. Additionally, HIPEF and HPP could be considered as promising technologies to obtain highly nutritional and functional beverages.

  15. Development activities of a CdTe/CdZnTe pixel detector for gamma-ray spectrometry with imaging and polarimetry capability in astrophysics

    NASA Astrophysics Data System (ADS)

    Gálvez, J. L.; Hernanz, M.; Álvarez, J. M.; Álvarez, L.; La Torre, M.; Caroli, E.; Lozano, M.; Pellegrini, G.; Ullán, M.; Cabruja, E.; Martínez, R.; Chmeissani, M.; Puigdengoles, C.

    2013-05-01

    In the last few years we have been working on feasibility studies of future instruments in the gamma-ray range, from several keV up to a few MeV, in collaboration with other research institutes. High sensitivities are essential to perform detailed studies of cosmic explosions and cosmic accelerators, e.g., Supernovae, Classical Novae, Supernova Remnants (SNRs), Gamma-Ray Bursts (GRBs), Pulsars, Active Galactic Nuclei (AGN).Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) are very attractive materials for gamma-ray detection, since they have already demonstrated their great performance onboard current space missions, such as IBIS/INTEGRAL and BAT/SWIFT, and future projects like ASIM onboard the ISS. However, the energy coverage of these instruments is limited up to a few hundred keV, and there has not been yet a dedicated instrument for polarimetry.Our research and development activities aim to study a gamma-ray imaging spectrometer in the MeV range based on CdTe detectors, suited either for the focal plane of a focusing mission or as a calorimeter for a Compton camera. In addition, our undergoing detector design is proposed as the baseline for the payload of a balloon-borne experiment dedicated to hard X- and soft gamma-ray polarimetry, currently under study and called CμSP (CZT μ-Spectrometer Polarimeter). Other research institutes such as INAF-IASF, DTU Space, LIP, INEM/CNR, CEA, are involved in this proposal. We will report on the main features of the prototype we are developing at the Institute of Space Sciences, a gamma-ray detector with imaging and polarimetry capabilities in order to fulfil the combined requirement of high detection efficiency with good spatial and energy resolution driven by the science.

  16. A novel peptide-modified and gene-activated biomimetic bone matrix accelerating bone regeneration.

    PubMed

    Pan, Haitao; Zheng, Qixin; Yang, Shuhua; Guo, Xiaodong; Wu, Bin; Zou, Zhenwei; Duan, Zhixia

    2014-08-01

    The osteogenic differentiation of bone marrow stromal cells (BMSCs) can be regulated by systemic or local growth factor, especially by transforming growth factor beta 1 (TGF-β1). However, how to maintain the bioactivity of exogenous TGF-β1 is a great challenge due to its short half-life time. The most promising solution is to transfer TGF-β1 gene into seed cells through transgenic technology and then transgenic cells to continuously secret endogenous TGF-β1 protein via gene expression. In this study, a novel non-viral vector (K)16GRGDSPC was chemically linked to bioactive bone matrices PLGA-[ASP-PEG]n using cross-linker to construct a novel non-viral gene transfer system. TGF-β1 gene was incubated with this system and subsequently rabbit-derived BMSCs were co-cultured with this gene-activated PLGA-[ASP-PEG]n, while co-cultured with PLGA-[ASP-PEG]n modified with (K)16GRGDSPC only and original PLGA-[ASP-PEG]n as control. Thus we fabricated three kinds of composites: Group A (BMSCs-TGF-β1DNA-(K)16GRGDSPC-PLGA-[ASP-PEG]n composite); Group B (BMSCs-(K)16GRGDSPC-PLGA-[ASP-PEG]n composite); and Group C (BMSCs-PLGA-[ASP-PEG]n composite). TGF-β1 and other osteogenic phenotype markers of alkaline phosphatase, osteocalcin, osteopontin and type I collagen in Group A were all significantly higher than the other two groups ex vivo. In vivo, 15-mm long segmental rabbit bone defects were created and randomly implanted the aforementioned composites separately, and then fixed with plate-screws. The results demonstrated that the implants in Group A significantly accelerated bone regeneration compared with the other implants based on X-rays, histological and biomechanical examinations. Therefore, we conclude this novel peptide-modified and gene-activated biomimetic bone matrix of TGF-β1DNA-(K)16GRGDSPC-PLGA-[ASP-PEG]n is a very promising scaffold biomaterial for accelerating bone regeneration. PMID:24115366

  17. Proceedings of PIXEL98 -- International pixel detector workshop

    SciTech Connect

    Anderson, D.F.; Kwan, S.

    1998-08-01

    Experiments around the globe face new challenges of more precision in the face of higher interaction rates, greater track densities, and higher radiation doses, as they look for rarer and rarer processes, leading many to incorporate pixelated solid-state detectors into their plans. The highest-readout rate devices require new technologies for implementation. This workshop reviewed recent, significant progress in meeting these technical challenges. Participants presented many new results; many of them from the weeks--even days--just before the workshop. Brand new at this workshop were results on cryogenic operation of radiation-damaged silicon detectors (dubbed the Lazarus effect). Other new work included a diamond sensor with 280-micron collection distance; new results on breakdown in p-type silicon detectors; testing of the latest versions of read-out chip and interconnection designs; and the radiation hardness of deep-submicron processes.

  18. Serial Pixel Analog-to-Digital Converter

    SciTech Connect

    Larson, E D

    2010-02-01

    This method reduces the data path from the counter to the pixel register of the analog-to-digital converter (ADC) from as many as 10 bits to a single bit. The reduction in data path width is accomplished by using a coded serial data stream similar to a pseudo random number (PRN) generator. The resulting encoded pixel data is then decoded into a standard hexadecimal format before storage. The high-speed serial pixel ADC concept is based on the single-slope integrating pixel ADC architecture. Previous work has described a massively parallel pixel readout of a similar architecture. The serial ADC connection is similar to the state-of-the art method with the exception that the pixel ADC register is a shift register and the data path is a single bit. A state-of-the-art individual-pixel ADC uses a single-slope charge integration converter architecture with integral registers and “one-hot” counters. This implies that parallel data bits are routed among the counter and the individual on-chip pixel ADC registers. The data path bit-width to the pixel is therefore equivalent to the pixel ADC bit resolution.

  19. A Novel Intracellular Isoform of Matrix Metalloproteinase-2 Induced by Oxidative Stress Activates Innate Immunity

    PubMed Central

    Lovett, David H.; Mahimkar, Rajeev; Raffai, Robert L.; Cape, Leslie; Maklashina, Elena; Cecchini, Gary; Karliner, Joel S.

    2012-01-01

    Background Experimental and clinical evidence has pinpointed a critical role for matrix metalloproteinase-2 (MMP-2) in ischemic ventricular remodeling and systolic heart failure. Prior studies have demonstrated that transgenic expression of the full-length, 68 kDa, secreted form of MMP-2 induces severe systolic failure. These mice also had unexpected and severe mitochondrial structural abnormalities and dysfunction. We hypothesized that an additional intracellular isoform of MMP-2, which affects mitochondrial function is induced under conditions of systolic failure-associated oxidative stress. Methodology and Principal Findings Western blots of cardiac mitochondria from the full length MMP-2 transgenics, ageing mice and a model of accelerated atherogenesis revealed a smaller 65 kDa MMP-2 isoform. Cultured cardiomyoblasts subjected to transient oxidative stress generated the 65 kDa MMP-2 isoform. The 65 kDa MMP-2 isoform was also induced by hypoxic culture of cardiomyoblasts. Genomic database analysis of the MMP-2 gene mapped transcriptional start sites and RNA transcripts induced by hypoxia or epigenetic modifiers within the first intron of the MMP-2 gene. Translation of these transcripts yields a 65 kDa N-terminal truncated isoform beginning at M77, thereby deleting the signal sequence and inhibitory prodomain. Cellular trafficking studies demonstrated that the 65 kDa MMP-2 isoform is not secreted and is present in cytosolic and mitochondrial fractions, while the full length 68 kDa isoform was found only in the extracellular space. Expression of the 65 kDa MMP-2 isoform induced mitochondrial-nuclear stress signaling with activation of the pro-inflammatory NF-κB, NFAT and IRF transcriptional pathways. By microarray, the 65 kDa MMP-2 induces an innate immunity transcriptome, including viral stress response genes, innate immunity transcription factor IRF7, chemokines and pro-apoptosis genes. Conclusion A novel N-terminal truncated intracellular isoform of MMP-2 is

  20. Penrose Pixels for Super-Resolution.

    PubMed

    Ben-Ezra, M; Lin, Zhouchen; Wilburn, Bennett; Zhang, Wei

    2011-07-01

    We present a novel approach to reconstruction-based super-resolution that uses aperiodic pixel tilings, such as a Penrose tiling or a biological retina, for improved performance. To this aim, we develop a new variant of the well-known error back projection super-resolution algorithm that makes use of the exact detector model in its back projection operator for better accuracy. Pixels in our model can vary in shape and size, and there may be gaps between adjacent pixels. The algorithm applies equally well to periodic or aperiodic pixel tilings. We present analysis and extensive tests using synthetic and real images to show that our approach using aperiodic layouts substantially outperforms existing reconstruction-based algorithms for regular pixel arrays. We close with a discussion of the feasibility of manufacturing CMOS or CCD chips with pixels arranged in Penrose tilings.

  1. Dead pixel replacement in LWIR microgrid polarimeters.

    PubMed

    Ratliff, Bradley M; Tyo, J Scott; Boger, James K; Black, Wiley T; Bowers, David L; Fetrow, Matthew P

    2007-06-11

    LWIR imaging arrays are often affected by nonresponsive pixels, or "dead pixels." These dead pixels can severely degrade the quality of imagery and often have to be replaced before subsequent image processing and display of the imagery data. For LWIR arrays that are integrated with arrays of micropolarizers, the problem of dead pixels is amplified. Conventional dead pixel replacement (DPR) strategies cannot be employed since neighboring pixels are of different polarizations. In this paper we present two DPR schemes. The first is a modified nearest-neighbor replacement method. The second is a method based on redundancy in the polarization measurements.We find that the redundancy-based DPR scheme provides an order-of-magnitude better performance for typical LWIR polarimetric data. PMID:19547086

  2. Virus based Full Colour Pixels using a Microheater.

    PubMed

    Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

    2015-01-01

    Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature's inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future. PMID:26334322

  3. Virus based Full Colour Pixels using a Microheater

    NASA Astrophysics Data System (ADS)

    Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

    2015-09-01

    Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature’s inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future.

  4. Virus based Full Colour Pixels using a Microheater

    PubMed Central

    Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

    2015-01-01

    Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature’s inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future. PMID:26334322

  5. Remote Sensing Classification Uncertainty: Validating Probabilistic Pixel Level Classification

    NASA Astrophysics Data System (ADS)

    Vrettas, Michail; Cornford, Dan; Bastin, Lucy; Pons, Xavier; Sevillano, Eva; Moré, Gerard; Serra, Pere; Ninyerola, Miquel

    2013-04-01

    There already exists an extensive literature on classification of remotely sensed imagery, and indeed classification more widely, that considers a wide range of probabilistic and non-probabilistic classification methodologies. Although for many probabilistic classification methodologies posterior class probabilities are produced per pixel (observation) these are often not communicated at the pixel level, and typically not validated at the pixel level. Most often the probabilistic classification in converted into a hard classification (of the most probable class) and the accuracy of the resulting classification is reported in terms of a global confusion matrix, or some score derived from this. For applications where classification accuracy is spatially variable and where pixel level estimates of uncertainty can be meaningfully exploited in workflows that propagate uncertainty validating and communicating the pixel level uncertainty opens opportunities for more refined and accountable modelling. In this work we describe our recent work applying and validation of a range of probabilistic classifiers. Using a multi-temporal Landsat data set of the Ebro Delta in Catalonia, which has been carefully radiometrically and geometrically corrected, we present a range of Bayesian classifiers from simple Bayesian linear discriminant analysis to a complex variational Gaussian process based classifier. Field study derived labelled data, classified into 8 classes, which primarily consider land use and the degree of flooding in what is a rice growing region, are used to train the pixel level classifiers. Our focus is not so much on the classification accuracy, but rather the validation of the probabilistic classification made by all methods. We present a range of validation plots and scores, many of which are used for probabilistic weather forecast verification, but are new to remote sensing classification including of course the standard measures of misclassification, but also

  6. [Hadamard transform spectrometer mixed pixels' unmixing method].

    PubMed

    Yan, Peng; Hu, Bing-Liang; Liu, Xue-Bin; Sun, Wei; Li, Li-Bo; Feng, Yu-Tao; Liu, Yong-Zheng

    2011-10-01

    Hadamard transform imaging spectrometer is a multi-channel digital transform spectrometer detection technology, this paper based on digital micromirror array device (DMD) of the Hadamard transform spectrometer working principle and instrument structure, obtained by the imaging sensor mixed pixel were analyzed, theory derived the solution of pixel aliasing hybrid method, simulation results show that the method is simple and effective to improve the accuracy of mixed pixel spectrum more than 10% recovery. PMID:22250574

  7. Method for fabricating pixelated silicon device cells

    SciTech Connect

    Nielson, Gregory N.; Okandan, Murat; Cruz-Campa, Jose Luis; Nelson, Jeffrey S.; Anderson, Benjamin John

    2015-08-18

    A method, apparatus and system for flexible, ultra-thin, and high efficiency pixelated silicon or other semiconductor photovoltaic solar cell array fabrication is disclosed. A structure and method of creation for a pixelated silicon or other semiconductor photovoltaic solar cell array with interconnects is described using a manufacturing method that is simplified compared to previous versions of pixelated silicon photovoltaic cells that require more microfabrication steps.

  8. High responsivity CMOS imager pixel implemented in SOI technology

    NASA Technical Reports Server (NTRS)

    Zheng, X.; Wrigley, C.; Yang, G.; Pain, B.

    2000-01-01

    Availability of mature sub-micron CMOS technology and the advent of the new low noise active pixel sensor (APS) concept have enabled the development of low power, miniature, single-chip, CMOS digital imagers in the decade of the 1990's.

  9. Pixel Analysis and Plasma Dynamics Characterized by Photospheric Spectral Data

    NASA Astrophysics Data System (ADS)

    Rasca, Anthony P.; Chen, James; Pevtsov, Alexei A.

    2016-05-01

    Recent observations of the photosphere using high spatial and temporal resolutions show small dynamic features at the resolving limit during emerging flux events. However, line-of-sight (LOS) magnetogram pixels only contain the net uncanceled magnetic flux, which is expected to increase for fixed regions as resolution limits improve. A new pixel dynamics method uses spectrographic images to characterize photospheric absorption line profiles by variations in line displacement, width, asymmetry, and peakedness and is applied to quiet-sun regions, active regions with no eruption, and an active region with an ongoing eruption. Using Stokes I images from SOLIS/VSM on 2012 March 13, variations in line width and peakedness of Fe I 6301.5 Å are shown to have a strong spatial and temporal relationship with an M7.9 X-ray flare originating from NOAA 11429. This relationship is observed as a flattening in the line profile as the X-ray flare approaches peak intensity and was not present in area scans of a non-eruptive active region on 2011 April 14. These results are used to estimate dynamic plasma properties on sub-pixel scales and provide both spatial and temporal information of sub-pixel activity at the photosphere. The analysis can be extended to include the full Stokes parameters and study signatures of magnetic fields and coupled plasma properties.

  10. Roles of mitogen activated protein kinases and EGF receptor in arsenite-stimulated matrix metalloproteinase-9 production

    SciTech Connect

    Cooper, Karen L.; Myers, Terrance Alix; Rosenberg, Martina; Chavez, Miquella; Hudson, Laurie G. . E-mail: lghudson@unm.edu

    2004-11-01

    The dermatotoxicity of arsenic is well established and epidemiological studies identify an increased incidence of keratinocytic tumors (basal cell and squamous cell carcinoma) associated with arsenic exposure. Little is known about the underlying mechanisms of arsenic-mediated skin carcinogenesis, but activation of mitogen-activated protein (MAP) kinases and subsequent regulation of downstream target genes may contribute to tumor promotion and progression. In this study, we investigated activation of the extracellular signal regulated kinase (ERK) and the stress-associated kinase p38 by arsenite in HaCat cells, a spontaneously immortalized human keratinocyte cell line. Arsenite concentrations {>=}100 {mu}M stimulate rapid activation of p38 and ERK MAP kinases. However, upon extended exposure (24 h), persistent stimulation of p38 and ERK MAP kinases was detected at low micromolar concentrations of arsenite. Although ERK and p38 were activated with similar time and concentration dependence, the mechanism of activation differed for these two MAP kinases. ERK activation by arsenite was fully dependent on the catalytic activity of the epidermal growth factor (EGF) receptor and partially dependent on Src-family kinase activity. In contrast, p38 activation was independent of EGF receptor or Src-family kinase activity. Arsenite-stimulated MAP kinase signal transduction resulted in increased production of matrix metalloproteinase (MMP)-9, an AP-1 regulated gene product. MMP-9 induction by arsenite was prevented when EGF receptor or MAP kinase signaling was inhibited. These studies indicate that EGF receptor activation is a component of arsenite-mediated signal transduction and gene expression in keratinocytes and that low micromolar concentrations of arsenite stimulate key signaling pathways upon extended exposure. Stimulation of MAP kinase cascades by arsenic and subsequent regulation of genes including c-fos, c-jun, and the matrix degrading proteases may play an important

  11. Commissioning of the CMS Forward Pixel Detector

    SciTech Connect

    Kumar, Ashish; /SUNY, Buffalo

    2008-12-01

    The Compact Muon Solenoid (CMS) experiment is scheduled for physics data taking in summer 2009 after the commissioning of high energy proton-proton collisions at Large Hadron Collider (LHC). At the core of the CMS all-silicon tracker is the silicon pixel detector, comprising three barrel layers and two pixel disks in the forward and backward regions, accounting for a total of 66 million channels. The pixel detector will provide high-resolution, 3D tracking points, essential for pattern recognition and precise vertexing, while being embedded in a hostile radiation environment. The end disks of the pixel detector, known as the Forward Pixel detector, has been assembled and tested at Fermilab, USA. It has 18 million pixel cells with dimension 100 x 150 {micro}m{sup 2}. The complete forward pixel detector was shipped to CERN in December 2007, where it underwent extensive system tests for commissioning prior to the installation. The pixel system was put in its final place inside the CMS following the installation and bake out of the LHC beam pipe in July 2008. It has been integrated with other sub-detectors in the readout since September 2008 and participated in the cosmic data taking. This report covers the strategy and results from commissioning of CMS forward pixel detector at CERN.

  12. Matrix metallopeptidase 2 activity in tendon regions: effects of mechanical loading exercise associated to anabolic-androgenic steroids.

    PubMed

    Marqueti, Rita C; Prestes, Jonato; Paschoal, Milena; Ramos, Oscar H P; Perez, Sérgio E A; Carvalho, Hernandes F; Selistre-de-Araujo, Heloisa S

    2008-12-01

    Matrix metallopeptidases (MMPs) are responsible for degradation of the extracellular matrix components and tissue remodeling. To achieve a better understanding of AAS effects in rat tendon, MMP-2 activity in the proximal and distal regions of the calcanear tendon (CT) and proximal, intermediate and distal region of superficial (SFT) and deep flexor tendons (DFT) after mechanical load exercise associated with AAS was investigated. Animals were grouped into four groups: sedentary animals (S); sedentary animals with ASS supplementation (S + A); trained animals (T) and trained animals with AAS supplementation (T + A). Analysis of MMP activity in tendon extracts was done by gelatin zymography. Both proximal and distal regions of the calcanear tendon showed the lowest MMP-2 concentration and the highest proportion in MMP-2 active form. The intermediate region of the SFT differed (P < 0.01) from the proximal and distal regions with higher % of active MMP-2 in the sedentary group. The proportion of active MMP-2 decreased in the proximal region of the CT. AAS treatment strongly decreased both MMP-2 concentration and active form in the three regions of the SFT and on the proximal region of the CT, but not on the DFT. The differences in the response to exercise and AAS treatment are a result of distinct metabolism and recruitment of these tendon regions in the exercise program employed in this study.

  13. Aryl Hydrocarbon Receptor Activation by TCDD Modulates Expression of Extracellular Matrix Remodeling Genes during Experimental Liver Fibrosis

    PubMed Central

    Lamb, Cheri L.; Cholico, Giovan N.; Perkins, Daniel E.; Fewkes, Michael T.; Oxford, Julia Thom; Lujan, Trevor J.; Morrill, Erica E.

    2016-01-01

    The aryl hydrocarbon receptor (AhR) is a soluble, ligand-activated transcription factor that mediates the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Increasing evidence implicates the AhR in regulating extracellular matrix (ECM) homeostasis. We recently reported that TCDD increased necroinflammation and myofibroblast activation during liver injury elicited by carbon tetrachloride (CCl4). However, TCDD did not increase collagen deposition or exacerbate fibrosis in CCl4-treated mice, which raises the possibility that TCDD may enhance ECM turnover. The goal of this study was to determine how TCDD impacts ECM remodeling gene expression in the liver. Male C57BL/6 mice were treated for 8 weeks with 0.5 mL/kg CCl4, and TCDD (20 μg/kg) was administered during the last two weeks. Results indicate that TCDD increased mRNA levels of procollagen types I, III, IV, and VI and the collagen processing molecules HSP47 and lysyl oxidase. TCDD also increased gelatinase activity and mRNA levels of matrix metalloproteinase- (MMP-) 3, MMP-8, MMP-9, and MMP-13. Furthermore, TCDD modulated expression of genes in the plasminogen activator/plasmin system, which regulates MMP activation, and it also increased TIMP1 gene expression. These findings support the notion that AhR activation by TCDD dysregulates ECM remodeling gene expression and may facilitate ECM metabolism despite increased liver injury.

  14. Aryl Hydrocarbon Receptor Activation by TCDD Modulates Expression of Extracellular Matrix Remodeling Genes during Experimental Liver Fibrosis

    PubMed Central

    Lamb, Cheri L.; Cholico, Giovan N.; Perkins, Daniel E.; Fewkes, Michael T.; Oxford, Julia Thom; Lujan, Trevor J.; Morrill, Erica E.

    2016-01-01

    The aryl hydrocarbon receptor (AhR) is a soluble, ligand-activated transcription factor that mediates the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Increasing evidence implicates the AhR in regulating extracellular matrix (ECM) homeostasis. We recently reported that TCDD increased necroinflammation and myofibroblast activation during liver injury elicited by carbon tetrachloride (CCl4). However, TCDD did not increase collagen deposition or exacerbate fibrosis in CCl4-treated mice, which raises the possibility that TCDD may enhance ECM turnover. The goal of this study was to determine how TCDD impacts ECM remodeling gene expression in the liver. Male C57BL/6 mice were treated for 8 weeks with 0.5 mL/kg CCl4, and TCDD (20 μg/kg) was administered during the last two weeks. Results indicate that TCDD increased mRNA levels of procollagen types I, III, IV, and VI and the collagen processing molecules HSP47 and lysyl oxidase. TCDD also increased gelatinase activity and mRNA levels of matrix metalloproteinase- (MMP-) 3, MMP-8, MMP-9, and MMP-13. Furthermore, TCDD modulated expression of genes in the plasminogen activator/plasmin system, which regulates MMP activation, and it also increased TIMP1 gene expression. These findings support the notion that AhR activation by TCDD dysregulates ECM remodeling gene expression and may facilitate ECM metabolism despite increased liver injury. PMID:27672655

  15. Implementation of TDI based digital pixel ROIC with 15μm pixel pitch

    NASA Astrophysics Data System (ADS)

    Ceylan, Omer; Shafique, Atia; Burak, A.; Caliskan, Can; Abbasi, Shahbaz; Yazici, Melik; Gurbuz, Yasar

    2016-05-01

    A 15um pixel pitch digital pixel for LWIR time delay integration (TDI) applications is implemented which occupies one fourth of pixel area compared to previous digital TDI implementation. TDI is implemented on 8 pixels with oversampling rate of 2. ROIC provides 16 bits output with 8 bits of MSB and 8 bits of LSB. Pixel can store 75 M electrons with a quantization noise of 500 electrons. Digital pixel TDI implementation is advantageous over analog counterparts considering power consumption, chip area and signal-to-noise ratio. Digital pixel TDI ROIC is fabricated with 0.18um CMOS process. In digital pixel TDI implementation photocurrent is integrated on a capacitor in pixel and converted to digital data in pixel. This digital data triggers the summation counters which implements TDI addition. After all pixels in a row contribute, the summed data is divided to the number of TDI pixels(N) to have the actual output which is square root of N improved version of a single pixel output in terms of signal-to-noise-ratio (SNR).

  16. Single chip camera active pixel sensor

    NASA Technical Reports Server (NTRS)

    Shaw, Timothy (Inventor); Pain, Bedabrata (Inventor); Olson, Brita (Inventor); Nixon, Robert H. (Inventor); Fossum, Eric R. (Inventor); Panicacci, Roger A. (Inventor); Mansoorian, Barmak (Inventor)

    2003-01-01

    A totally digital single chip camera includes communications to operate most of its structure in serial communication mode. The digital single chip camera include a D/A converter for converting an input digital word into an analog reference signal. The chip includes all of the necessary circuitry for operating the chip using a single pin.

  17. Active Pixel Sensors for electron microscopy

    NASA Astrophysics Data System (ADS)

    Denes, P.; Bussat, J.-M.; Lee, Z.; Radmillovic, V.

    2007-09-01

    The technology used for monolithic CMOS imagers, popular for cell phone cameras and other photographic applications, has been explored for charged particle tracking by the high-energy physics community for several years. This technology also lends itself to certain imaging detector applications in electron microscopy. We have been developing such detectors for several years at Lawrence Berkeley National Laboratory, and we and others have shown that this technology can offer excellent point-spread function, direct detection and high readout speed. In this paper, we describe some of the design constraints peculiar to electron microscopy and summarize where such detectors could play a useful role.

  18. Active matrix organic light emitting diode (AMOLED)-XL performance and life test results

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Wood, Michael V.; Hastings, Arthur R., Jr.; Draper, Russell S.; Lum, Alden K.; Ghosh, Amalkumar P.; Prache, Olivier; Wacyk, Ihor

    2009-05-01

    The US Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to characterize the ongoing improvements in the lifetime of OLED displays. This CRADA also called for the evaluation of OLED performance as the need arises, especially when new products are developed or when a previously untested parameter needs to be understood. In 2006, eMagin Corporation developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications. RDECOM CERDEC NVESD conducted life tests on these displays, finding over 200% lifetime improvement for the OLED-XL devices over the standard OLED displays, publishing results at the 2007 and 2008 SPIE Defense and Security Symposia1,2. In 2008, eMagin Corporation made additional improvements on the lifetime of their displays and developed the first SXGA (1280 × 1024 triad pixels) OLED microdisplay. A summary of the life and performance tests run at CERDEC NVESD will be presented along with a recap of previous data. This should result in a better understanding of the applicability of AMOLEDs in military and commercial head mounted systems: where good fits are made, and where further development might be desirable.

  19. Active matrix organic light emitting diode (AMOLED) performance and life test results

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Wood, Michael V.; Hastings, Arthur R., Jr.; Draper, Russell S.; Lum, Alden K.; Ghosh, Amalkumar P.; Prache, Olivier; Wacyk, Ihor

    2010-04-01

    The US Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to characterize the ongoing improvements in the lifetime of OLED displays. This CRADA also called for the evaluation of OLED performance as the need arises, especially when new products are developed or when a previously untested parameter needs to be understood. In 2006, eMagin Corporation developed long-life OLED-XLTM devices for use in their AMOLED microdisplays for head-worn applications. Through Research and Development programs from 2007 to 2009 with the US Government, eMagin made additional improvements in OLED life and developed the first SXGA (1280 × 1024 triad pixels) OLED microdisplay. US Army RDECOM CERDEC NVESD conducted life and performance tests on these displays, publishing results at the 2007, 2008, and 2009 SPIE Defense and Security Symposia1,2,3. Life and performance tests have continued through 2009, and this data will be presented along with a recap of previous data. This should result in a better understanding of the applicability of AMOLEDs in military and commercial head mounted systems: where good fits are made, and where further development might be desirable.

  20. Active matrix organic light emitting diode (AMOLED) performance and life test results

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Wood, Michael V.; Hastings, Arthur R., Jr.; Draper, Russell S.; Ghosh, Amalkumar; Prache, Olivier; Wacyk, Ihor

    2012-06-01

    The US Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to characterize the ongoing improvements in the lifetime of OLED displays. This CRADA also called for the evaluation of OLED performance as the need arises, especially when new products are developed or when a previously untested parameter needs to be understood. In 2006, eMagin Corporation developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications. Through Research and Development programs from 2007 to 2011 with the US Government, eMagin made additional improvements in OLED life and developed the first SXGA (1280 X 1024 triad pixels) and WUXGA (1920 X 1200) OLED microdisplays. US Army RDECOM CERDEC NVESD conducted life and performance tests on these displays, publishing results at the 2011, 2010, 2009, 2008, and 2007 SPIE Defense, Security and Sensing Symposia1,2,3,4,5. Life and performance tests have continued through 2012, and this data will be presented along with a recap of previous data. This should result in a better understanding of the applicability of AMOLEDs in military and commercial head mounted systems by determining where good fits are made and where further development might be desirable.

  1. Active matrix organic light-emitting diode (AMOLED) performance and life test results

    NASA Astrophysics Data System (ADS)

    Fellowes, David A.; Wood, Michael V.; Hastings, Arthur R., Jr.; Draper, Russell S.; Ghosh, Amalkumar; Prache, Olivier; Wacyk, Ihor; Ali, Tariq; Khayrullin, Ilyas

    2011-06-01

    The US Army and eMagin Corporation established a Cooperative Research and Development Agreement (CRADA) to characterize the ongoing improvements in the lifetime of OLED displays. This CRADA also called for the evaluation of OLED performance as the need arises, especially when new products are developed or when a previously untested parameter needs to be understood. In 2006, eMagin Corporation developed long-life OLED-XL devices for use in their AMOLED microdisplays for head-worn applications. Through research and development programs from 2007 to 2010 with the US Government, eMagin made additional improvements in OLED life and developed the first SXGA (1280 X 1024 triad pixels) OLED microdisplay. US Army RDECOM CERDEC NVESD conducted life and performance tests on these displays, publishing results at the 2007, 2008, 2009, and 2010 SPIE Defense and Security Symposia1,2,3,4. Life and performance tests have continued through 2010, and this data will be presented along with a recap of previous data. This should result in a better understanding of the applicability of AMOLEDs in military and commercial head mounted systems: where good fits are made, and where further development might be desirable.

  2. Matrix-M™ Adjuvant Induces Local Recruitment, Activation and Maturation of Central Immune Cells in Absence of Antigen

    PubMed Central

    Reimer, Jenny M.; Karlsson, Karin H.; Lövgren-Bengtsson, Karin; Magnusson, Sofia E.; Fuentes, Alexis; Stertman, Linda

    2012-01-01

    Saponin-based adjuvants are widely used to enhance humoral and cellular immune responses towards vaccine antigens, although it is not yet completely known how they mediate their stimulatory effects. The aim of this study was to elucidate the mechanism of action of adjuvant Matrix-M™ without antigen and Alum was used as reference adjuvant. Adjuvant Matrix-M™ is comprised of 40 nm nanoparticles composed of Quillaja saponins, cholesterol and phospholipid. BALB/c mice were subcutaneously injected once with, 3, 12 or 30 µg of Matrix-M™, resulting in recruitment of leukocytes to draining lymph nodes (dLNs) and spleen 48 h post treatment. Flow cytometry analysis identified CD11b+ Gr-1high granulocytes as the cell population increasing most in dLNs and spleen. Additionally, dendritic cells, F4/80int cells, T-, B- and NK-cells were recruited to dLNs and in spleen the number of F4/80int cells, and to some extent, B cells and dendritic cells, increased. Elevated levels of early activation marker CD69 were detected on T-, B- and NK-cells, CD11b+ Gr-1high cells, F4/80int cells and dendritic cells in dLNs. In spleen CD69 was mainly up-regulated on NK cells. B cells and dendritic cells in dLNs and spleen showed an increased expression of the co-stimulatory molecule CD86 and dendritic cells in dLNs expressed elevated levels of MHC class II. The high-dose (30 µg) of Matrix-M™ induced detectable serum levels of IL-6 and MIP-1β 4 h post administration, most likely representing spillover of locally produced cytokines. A lesser increase of IL-6 in serum after administration of 12 µg Matrix-M™ was also observed. In conclusion, early immunostimulatory properties were demonstrated by Matrix-M™ alone, as therapeutic doses resulted in a local transient immune response with recruitment and activation of central immune cells to dLNs. These effects may play a role in enhancing uptake and presentation of vaccine antigens to elicit a competent immune response. PMID:22844480

  3. Inducible Nitric Oxide Synthase Deficiency Impairs Matrix Metalloproteinase-9 Activity and Disrupts Leukocyte Migration in Hepatic Ischemia/Reperfusion Injury

    PubMed Central

    Hamada, Takashi; Duarte, Sergio; Tsuchihashi, Seiichiro; Busuttil, Ronald W.; Coito, Ana J.

    2009-01-01

    Matrix metalloproteinase 9 (MMP-9) is a critical mediator of leukocyte migration in hepatic ischemia/reperfusion (I/R) injury. To test the relevance of inducible nitric oxide synthase (iNOS) expression on the regulation of MMP-9 activity in liver I/R injury, our experiments included both iNOS-deficient mice and mice treated with ONO-1714, a specific iNOS inhibitor. The inability of iNOS-deficient mice to generate iNOS-derived nitric oxide (NO) profoundly inhibited MMP-9 activity and depressed leukocyte migration in livers after I/R injury. While macrophages expressed both iNOS and MMP-9 in damaged wild-type livers, neutrophils expressed MMP-9 and were virtually negative for iNOS; however, exposure of isolated murine neutrophils and macrophages to exogenous NO increased MMP-9 activity in both cell types, suggesting that NO may activate MMP-9 in leukocytes by either autocrine or paracrine mechanisms. Furthermore, macrophage NO production through the induction of iNOS was capable of promoting neutrophil transmigration across fibronectin in a MMP-9-dependent manner. iNOS expression in liver I/R injury was also linked to liver apoptosis, which was reduced in the absence of MMP-9. These results suggest that MMP-9 activity induced by iNOS-derived NO may also lead to detachment of hepatocytes from the extracellular matrix and cell death, in addition to regulating leukocyte migration across extracellular matrix barriers. These data provide evidence for a novel mechanism by which MMP-9 can mediate iNOS-induced liver I/R injury. PMID:19443702

  4. How, with whom and when: an overview of CD147-mediated regulatory networks influencing matrix metalloproteinase activity

    PubMed Central

    Grass, G. Daniel; Toole, Bryan P.

    2015-01-01

    Matrix metalloproteinases (MMPs) comprise a family of 23 zinc-dependent enzymes involved in various pathologic and physiologic processes. In cancer, MMPs contribute to processes from tumour initiation to establishment of distant metastases. Complex signalling and protein transport networks regulate MMP synthesis, cell surface presentation and release. Earlier attempts to disrupt MMP activity in patients have proven to be intolerable and with underwhelming clinical efficacy; thus targeting ancillary proteins that regulate MMP activity may be a useful therapeutic approach. Extracellular matrix metalloproteinase inducer (EMMPRIN) was originally characterized as a factor present on lung cancer cells, which stimulated collagenase (MMP-1) production in fibroblasts. Subsequent studies demonstrated that EMMPRIN was identical with several other protein factors, including basigin (Bsg), all of which are now commonly termed CD147. CD147 modulates the synthesis and activity of soluble and membrane-bound [membrane-type MMPs (MT-MMPs)] in various contexts via homophilic/heterophilic cell interactions, vesicular shedding or cell-autonomous processes. CD147 also participates in inflammation, nutrient and drug transporter activity, microbial pathology and developmental processes. Despite the hundreds of manuscripts demonstrating CD147-mediated MMP regulation, the molecular underpinnings governing this process have not been fully elucidated. The present review summarizes our present knowledge of the complex regulatory systems influencing CD147 biology and provides a framework to understand how CD147 may influence MMP activity. PMID:26604323

  5. Biochemical and toxicological evaluation of nano-heparins in cell functional properties, proteasome activation and expression of key matrix molecules.

    PubMed

    Piperigkou, Zoi; Karamanou, Konstantina; Afratis, Nikolaos A; Bouris, Panagiotis; Gialeli, Chrysostomi; Belmiro, Celso L R; Pavão, Mauro S G; Vynios, Dimitrios H; Tsatsakis, Aristidis M

    2016-01-01

    The glycosaminoglycan heparin and its derivatives act strongly on blood coagulation, controlling the activity of serine protease inhibitors in plasma. Nonetheless, there is accumulating evidence highlighting different anticancer activities of these molecules in numerous types of cancer. Nano-heparins may have great biological significance since they can inhibit cell proliferation and invasion as well as inhibiting proteasome activation. Moreover, they can cause alterations in the expression of major modulators of the tumor microenvironment, regulating cancer cell behavior. In the present study, we evaluated the effects of two nano-heparin formulations: one isolated from porcine intestine and the other from the sea squirt Styela plicata, on a breast cancer cell model. We determined whether these nano-heparins are able to affect cell proliferation, apoptosis and invasion, as well as proteasome activity and the expression of extracellular matrix molecules. Specifically, we observed that nano-Styela compared to nano-Mammalian analogue has higher inhibitory role on cell proliferation, invasion and proteasome activity. Moreover, nano-Styela regulates cell apoptosis, expression of inflammatory molecules, such as IL-6 and IL-8 and reduces the expression levels of extracellular matrix macromolecules, such as the proteolytic enzymes MT1-MMP, uPA and the cell surface proteoglycans syndecan-1 and -2, but not on syndecan-4. The observations reported in the present article indicate that nano-heparins and especially ascidian heparin are effective agents for heparin-induced effects in critical cancer cell functions, providing an important possibility in pharmacological targeting.

  6. Supplemental Immobilization of Hanford Low-Activity Waste: Cast Stone Augmented Formulation Matrix Tests

    SciTech Connect

    Cozzi, A.; Crawford, C.; Fox, K.; Hansen, E.; Roberts, K.

    2015-07-20

    More than 56 million gallons of radioactive and hazardous waste are stored in 177 underground storage tanks at the U.S. Department of Energy’s (DOE’s) Hanford Site in Washington State. The HLW will be vitrified in the HLW facility for ultimate disposal at an offsite federal repository. A portion (~35%) of the LAW will be vitrified in the LAW vitrification facility for disposal onsite at the Integrated Disposal Facility (IDF). The pretreatment and HLW vitrification facilities will have the capacity to treat and immobilize all of the wastes destined for those facilities. However, a second facility will be needed for the expected volume of LAW requiring immobilization. Cast Stone, a cementitious waste form, is being considered to provide the required additional LAW immobilization capacity. The Cast Stone waste form must be acceptable for disposal in the IDF. The Cast Stone waste form and immobilization process must be tested to demonstrate that the final Cast Stone waste form can comply with the waste acceptance criteria for the disposal facility and that the immobilization processes can be controlled to consistently provide an acceptable waste form product. A testing program was developed in fiscal year (FY) 2012 describing in detail the work needed to develop and qualify Cast Stone as a waste form for the solidification of Hanford LAW. A statistically designed test matrix was used to evaluate the effects of key parameters on the properties of the Cast Stone as it is initially prepared and after curing. For the processing properties, the water-to-dry-blend mix ratio was the most significant parameter in affecting the range of values observed for each property. The single shell tank (SST) Blend simulant also showed differences in measured properties compared to the other three simulants tested. A review of the testing matrix and results indicated that an additional set of tests would be beneficial to improve the understanding of the impacts noted in the Screening

  7. Smart-pixel spatial light modulator for incorporation in an optoelectronic neural network.

    PubMed

    Bar-Tana, I; Sharpe, J P; McKnight, D J; Johnson, K M

    1995-02-01

    We present the design, fabrication, and testing of a novel liquid-crystal-on-silicon optically addressed spatial light modulator for use as a weight matrix in an ART-1 optoelectronic neural processor. Each pixel in the 50 x 83 element array occupies 75 microm x 75 microm and consists of a photodetector, a threshold circuit, a 1-bit (flip-flop) memory element, and a liquid-crystal modulating mirror. The array is designed to switch all the pixels initially to the ON state. Subsequently each pixel is independently switched to the OFF state if a superthreshold amount of light falls upon the pixel's photodetector. The device has a contrast ratio of 20:1, a switch-on time (10-90% rise time) of 500 micros, and a switch-off time of ~500 micros (depending on the externally set threshold). Measured device uniformities and interpixel coupling are also described. PMID:19859168

  8. Modulation of Active Site Electronic Structure by the Protein Matrix to Control [NiFe] Hydrogenase Reactivity

    SciTech Connect

    Smith, Dayle MA; Raugei, Simone; Squier, Thomas C.

    2014-09-30

    Control of the reactivity of the nickel center of the [NiFe] hydrogenase and other metalloproteins commonly involves outer coordination sphere ligands that act to modify the geometry and physical properties of the active site metal centers. We carried out a combined set of classical molecular dynamics and quantum/classical mechanics calculations to provide quantitative estimates of how dynamic fluctuations of the active site within the protein matrix modulate the electronic structure at the catalytic center. Specifically we focused on the dynamics of the inner and outer coordination spheres of the cysteinate-bound Ni–Fe cluster in the catalytically active Ni-C state. There are correlated movements of the cysteinate ligands and the surrounding hydrogen-bonding network, which modulate the electron affinity at the active site and the proton affinity of a terminal cysteinate. On the basis of these findings, we hypothesize a coupling between protein dynamics and electron and proton transfer reactions critical to dihydrogen production.

  9. High stroke pixel for a deformable mirror

    DOEpatents

    Miles, Robin R.; Papavasiliou, Alexandros P.

    2005-09-20

    A mirror pixel that can be fabricated using standard MEMS methods for a deformable mirror. The pixel is electrostatically actuated and is capable of the high deflections needed for spaced-based mirror applications. In one embodiment, the mirror comprises three layers, a top or mirror layer, a middle layer which consists of flexures, and a comb drive layer, with the flexures of the middle layer attached to the mirror layer and to the comb drive layer. The comb drives are attached to a frame via spring flexures. A number of these mirror pixels can be used to construct a large mirror assembly. The actuator for the mirror pixel may be configured as a crenellated beam with one end fixedly secured, or configured as a scissor jack. The mirror pixels may be used in various applications requiring high stroke adaptive optics.

  10. Vascular smooth muscle cells from injured rat aortas display elevated matrix production associated with transforming growth factor-beta activity.

    PubMed Central

    Rasmussen, L. M.; Wolf, Y. G.; Ruoslahti, E.

    1995-01-01

    The arterial response to injury is characterized by a short period of increased proliferation and migration of vascular smooth muscle cells, followed by an extended period of extracellular matrix accumulation in the intima. Transforming growth factor-beta (TGF-beta) has been implicated as a causative factor in the formation of extracellular matrix in this process, which leads to progressive thickening of the intima, known as intimal hyperplasia. In vitro analysis of vascular smooth muscle cells harvested from normal rat aortas and from aortas injured 14 days earlier showed that both types of cells attached equally well to culture dishes but that the initial spreading of the cells was increased in cells derived from injured vessels. Cells from the injured arteries produced more fibronectin and proteoglycans into the culture medium than the cells from normal arteries and contained more TGF-beta 1 mRNA. TGF-beta 1 increased proteoglycan synthesis by normal smooth muscle cells, and the presence of a neutralizing anti-TGF-beta 1 antibody reduced proteoglycan synthesis by the cells from injured arteries in culture. Fibronectin synthesis was not altered by these treatments. These results indicate that the accumulation of extracellular matrix components in neointimal lesions is at least partially caused by autocrine TGF-beta activity in vascular smooth muscle cells. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:7573349

  11. MicroRNA-375 Suppresses Extracellular Matrix Degradation and Invadopodial Activity in Head and Neck Squamous Cell Carcinoma

    PubMed Central

    Jimenez, Lizandra; Sharma, Ved P.; Condeelis, John; Harris, Thomas; Ow, Thomas J.; Prystowsky, Michael B.; Childs, Geoffrey; Segall, Jeffrey E.

    2015-01-01

    Context Head and neck squamous cell carcinoma (HNSCC) is a highly invasive cancer with an association with locoregional recurrence and lymph node metastasis. We have previously reported that low microRNA-375 (miR-375) expression levels correlate with poor patient survival, increased locoregional recurrence, and distant metastasis. Increasing miR-375 expression in HNSCC cell lines to levels found in normal cells results in suppressed invasive properties. HNSCC invasion is mediated in part by invadopodia-associated degradation of the extracellular matrix. Objective To determine whether elevated miR-375 expression in HNSCC cell lines also affects invadopodia formation and activity. Design For evaluation of the matrix degradation properties of the HNSCC lines, an invadopodial matrix degradation assay was used. The total protein levels of invadopodia-associated proteins were measured by Western blot analyses. Immunoprecipitation experiments were conducted to evaluate the tyrosine phosphorylation state of cortactin. Human Protease Arrays were used for the detection of the secreted proteases. Quantitative real time–polymerase chain reaction measurements were used to evaluate the messenger RNA (mRNA) expression of the commonly regulated proteases. Results Increased miR-375 expression in HNSCC cells suppresses extracellular matrix degradation and reduces the number of mature invadopodia. Higher miR-375 expression does not reduce cellular levels of selected invadopodia-associated proteins, nor is tyrosine phosphorylation of cortactin altered. However, HNSCC cells with higher miR-375 expression had significant reductions in the mRNA expression levels and secreted levels of specific proteases. Conclusions MicroRNA-375 regulates invadopodia maturation and function potentially by suppressing the expression and secretion of proteases. PMID:26172508

  12. Smart-Pixel Array Processors Based on Optimal Cellular Neural Networks for Space Sensor Applications

    NASA Technical Reports Server (NTRS)

    Fang, Wai-Chi; Sheu, Bing J.; Venus, Holger; Sandau, Rainer

    1997-01-01

    A smart-pixel cellular neural network (CNN) with hardware annealing capability, digitally programmable synaptic weights, and multisensor parallel interface has been under development for advanced space sensor applications. The smart-pixel CNN architecture is a programmable multi-dimensional array of optoelectronic neurons which are locally connected with their local neurons and associated active-pixel sensors. Integration of the neuroprocessor in each processor node of a scalable multiprocessor system offers orders-of-magnitude computing performance enhancements for on-board real-time intelligent multisensor processing and control tasks of advanced small satellites. The smart-pixel CNN operation theory, architecture, design and implementation, and system applications are investigated in detail. The VLSI (Very Large Scale Integration) implementation feasibility was illustrated by a prototype smart-pixel 5x5 neuroprocessor array chip of active dimensions 1380 micron x 746 micron in a 2-micron CMOS technology.

  13. The extracellular matrix proteins laminin and fibronectin contain binding domains for human plasminogen and tissue plasminogen activator.

    PubMed

    Moser, T L; Enghild, J J; Pizzo, S V; Stack, M S

    1993-09-01

    This study describes the binding of plasminogen and tissue-type plasminogen activator (t-PA) to the extracellular matrix proteins fibronectin and laminin. Plasminogen bound specifically and saturably to both fibronectin and laminin immobilized on microtiter wells, with Kd(app) values of 115 and 18 nM, respectively. Limited proteolysis by endoproteinase V8 coupled with ligand blotting analysis showed that both plasminogen and t-PA preferentially bind to a 55-kDa fibronectin fragment and a 38-kDa laminin fragment. Amino acid sequence analysis demonstrated that the 5-kDa fragment originates with the fibronectin amino terminus whereas the laminin fragment was derived from the carboxyl-terminal globular domain of the laminin A chain. Ligand blotting experiments using isolated plasminogen domains were also used to identify distinct regions of the plasminogen molecule involved in fibronectin and laminin binding. Solution phase fibronectin binding to immobilized plasminogen was mediated primarily via lysine binding site-dependent interactions with plasminogen kringles 1-4. Lysine binding site-dependent binding of soluble laminin to immobilized plasminogen kringles 1-5 as well as an additional lysine binding site-independent interaction between mini-plasminogen and the 38-kDa laminin A chain fragment were also observed. These studies demonstrate binding of plasminogen and tissue-type plasminogen activator to specific regions of the extracellular matrix glycoproteins laminin and fibronectin and provide further insight into the mechanism of regulation of plasminogen activation by components of the extracellular matrix. PMID:8360181

  14. Solution-Processed Organic Thin-Film Transistor Array for Active-Matrix Organic Light-Emitting Diode

    NASA Astrophysics Data System (ADS)

    Harada, Chihiro; Hata, Takuya; Chuman, Takashi; Ishizuka, Shinichi; Yoshizawa, Atsushi

    2013-05-01

    We developed a 3-in. organic thin-film transistor (OTFT) array with an ink-jetted organic semiconductor. All layers except electrodes were fabricated by solution processes. The OTFT performed well without hysteresis, and the field-effect mobility in the saturation region was 0.45 cm2 V-1 s-1, the threshold voltage was 3.3 V, and the on/off current ratio was more than 106. We demonstrated a 3-in. active-matrix organic light-emitting diode (AMOLED) display driven by the OTFT array. The display could provide clear moving images. The peak luminance of the display was 170 cd/m2.

  15. Low Power, Red, Green and Blue Carbon Nanotube Enabled Vertical Organic Light Emitting Transistors for Active Matrix OLED Displays

    SciTech Connect

    McCarthy, M. A.; Liu, B.; Donoghue, E. P.; Kravchenko, Ivan I; Kim, D. Y.; So, Franky; Rinzler, A. G.

    2011-01-01

    Organic semiconductors are potential alternatives to polycrystalline silicon as the semiconductor used in the backplane of active matrix organic light emitting diode displays. Demonstrated here is a light-emitting transistor with an organic channel, operating with low power dissipation at low voltage, and high aperture ratio, in three colors: red, green and blue. The single-wall carbon nanotube network source electrode is responsible for the high level of performance demonstrated. A major benefit enabled by this architecture is the integration of the drive transistor, storage capacitor and light emitter into a single device. Performance comparable to commercialized polycrystalline-silicon TFT driven OLEDs is demonstrated.

  16. Ras activation mediates WISP-1-induced increases in cell motility and matrix metalloproteinase expression in human osteosarcoma.

    PubMed

    Wu, Chien-Lin; Tsai, Hsiao-Chi; Chen, Zhen-Wei; Wu, Chi-Ming; Li, Te-Mao; Fong, Yi-Chin; Tang, Chih-Hsin

    2013-12-01

    WISP-1 is a cysteine-rich protein that belongs to the CCN (Cyr61, CTGF, Nov) family of matrix cellular proteins. Osteosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. However, the effect of WISP-1 on migration activity in human osteosarcoma cells is mostly unknown. In this study, we first found that the expression of WISP-1 in osteosarcoma patients was significantly higher than that in normal bone and corrected with tumor stage. Exogenous treatment of osteosarcoma cells with WISP-1 promoted cell motility and matrix metalloproteinase (MMP)-2 and MMP-9 expression. In addition, the Ras and Raf-1 inhibitor or siRNA abolished WISP-1-induced cell migration and MMP expression. On the other hand, activation of the Ras, Raf-1, MEK, ERK, and NF-κB signaling pathway after WISP-1 treatment was demonstrated, and WISP-1-induced expression of MMPs and migration activity were inhibited by the specific inhibitor, and mutant of MEK, ERK, and NF-κB cascades. Taken together, our results indicated that WISP-1 enhances the migration of osteosarcoma cells by increasing MMP-2 and MMP-9 expression through the integrin receptor, Ras, Raf-1, MEK, ERK, and NF-κB signal transduction pathway.

  17. Broccoli and watercress suppress matrix metalloproteinase-9 activity and invasiveness of human MDA-MB-231 breast cancer cells.

    PubMed

    Rose, Peter; Huang, Qing; Ong, Choon Nam; Whiteman, Matt

    2005-12-01

    A high dietary intake of cruciferous vegetables has been associated with a reduction in numerous human pathologies particularly cancer. In the current study, we examined the inhibitory effects of broccoli (Brassica oleracea var. italica) and watercress (Rorripa nasturtium aquaticum) extracts on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cancer cell invasion and matrix metalloproteinase-9 activity using human MDA-MB-231 breast cancer cells. Aberrant overexpression of matrix metalloproteinases, including metalloproteinase-9, is associated with increased invasive potential in cancer cell lines. Our results demonstrate that extracts of broccoli and Rorripa suppressed TPA-induced MMP-9 activity and invasiveness in a concentration dependent manner as determined by zymographic analysis. Furthermore, fractionation of individual extracts followed by liquid chromatography mass spectroscopy analysis (LC-MS) revealed that the inhibitory effects of each vegetable were associated with the presence of 4-methysulfinylbutyl (sulforaphane) and 7-methylsulphinylheptyl isothiocyanates. Taken together, our data indicate that isothiocyanates derived form broccoli and Rorripa inhibit metalloproteinase 9 activities and also suppress the invasive potential of human MDA-MB-231 breast cancer cells in vitro. The inhibitory effects observed in the current study may contribute to the suppression of carcinogenesis by diets high in cruciferous vegetables.

  18. Broccoli and watercress suppress matrix metalloproteinase-9 activity and invasiveness of human MDA-MB-231 breast cancer cells

    SciTech Connect

    Rose, Peter . E-mail: bchpcr@nus.edu.sg; Huang, Qing; Ong, Choon Nam; Whiteman, Matt

    2005-12-01

    A high dietary intake of cruciferous vegetables has been associated with a reduction in numerous human pathologies particularly cancer. In the current study, we examined the inhibitory effects of broccoli (Brassica oleracea var. italica) and watercress (Rorripa nasturtium aquaticum) extracts on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cancer cell invasion and matrix metalloproteinase-9 activity using human MDA-MB-231 breast cancer cells. Aberrant overexpression of matrix metalloproteinases, including metalloproteinase-9, is associated with increased invasive potential in cancer cell lines. Our results demonstrate that extracts of broccoli and Rorripa suppressed TPA-induced MMP-9 activity and invasiveness in a concentration dependant manner as determined by zymographic analysis. Furthermore, fractionation of individual extracts followed by liquid chromatography mass spectroscopy analysis (LC-MS) revealed that the inhibitory effects of each vegetable were associated with the presence of 4-methysulfinylbutyl (sulforaphane) and 7-methylsulphinylheptyl isothiocyanates. Taken together, our data indicate that isothiocyanates derived form broccoli and Rorripa inhibit metalloproteinase 9 activities and also suppress the invasive potential of human MDA-MB-231 breast cancer cells in vitro. The inhibitory effects observed in the current study may contribute to the suppression of carcinogenesis by diets high in cruciferous vegetables.

  19. Back-side-illuminated 1.4μm pixel with a vertically pinned photodiode based on hole collection, PMOS readout chain and active side-wall passivation

    NASA Astrophysics Data System (ADS)

    Mamdy, Bastien; Roy, François; Ahmed, Nayera; Lu, Guo-Neng

    2015-10-01

    To further improve the characteristics of CMOS image sensors (CIS), we propose a back-side illuminated pixel integrating a vertically pinned and P-type photodiode (which collects holes) and PMOS readout circuitry. It has been designed in a 1.4μm-pitch, a two-transistor (2T) shared readout architecture and fabricated in a combined 65nm and 90nm technology. The vertically pinned photodiode takes up almost the entire volume of the pixel, allowing a full well capacity (FWC) exceeding 7000h+. With a conversion factor around 120μV/h+, the output swing approaching 1V is achieved on the column voltage. The pixel also integrates capacitive deep trench isolation (CDTI) to tackle electrical and optical crosstalk issues. The effective passivation of trench interface by CDTI bias control is demonstrated for a hole-based pixel. As expected, PMOS transistors have much lower trapping noise compared to NMOS counterparts. The PMOS source follower has an average temporal noise of 195μV, mainly dominated by thermal noise contribution.

  20. The Matrix Metalloproteinase Gene GmMMP2 Is Activated in Response to Pathogenic Infections in Soybean1

    PubMed Central

    Liu, Yongqing; Dammann, Christian; Bhattacharyya, Madan K.

    2001-01-01

    Matrix metalloproteinases (MMPs) play an important role in host defense responses against pathogens in mammals where their activities lead to the production of antimicrobial peptides. We have identified a novel soybean (Glycine max) metalloproteinase gene, GmMMP2, that is transcriptionally up-regulated in infected tissues. The deduced amino acid sequence indicates that this gene belongs to the MMP family. It is a preproprotein containing an N-terminal signal peptide, a cysteine switch, a zinc-binding catalytic motif, and a C-terminal transmembrane domain. The GmMMP2 expressed in and purified from Escherichia coli exhibited an in vitro enzymatic activity in digesting myelin basic protein. All plant metalloproteinases reported so far have no known functions. However, they have been suggested to be involved in extracellular cell matrix degradation during development or senescence. Our investigations demonstrate that the GmMMP2 transcript levels were rapidly increased in compatible and incompatible interactions of soybean tissues with the oomycete pathogen Phytophthora sojae or the bacterial pathogen Pseudomonas syringae pv. glycinea. In agreement with the GmMMP2 activation, a metalloproteinase activity was gradually increased in suspension-cultured cells following the bacterial infection. GmMMP2 was also activated in response to wounding and dehydration. However, GmMMP2 activation did not correlate with the oxidative burst leading to the hypersensitive response cell death or the tissue senescence progress that involves programmed cell death. Our investigations suggest that GmMMP2 may be involved in a novel defense response of soybean against pathogenic infections. PMID:11743122

  1. Pixel multichip module development at Fermilab

    SciTech Connect

    Turqueti, M A; Cardoso, G; Andresen, J; Appel, J A; Christian, D C; Kwan, S W; Prosser, A; Uplegger, L

    2005-10-01

    At Fermilab, there is an ongoing pixel detector R&D effort for High Energy Physics with the objective of developing high performance vertex detectors suitable for the next generation of HEP experiments. The pixel module presented here is a direct result of work undertaken for the canceled BTeV experiment. It is a very mature piece of hardware, having many characteristics of high performance, low mass and radiation hardness driven by the requirements of the BTeV experiment. The detector presented in this paper consists of three basic devices; the readout integrated circuit (IC) FPIX2A [2][5], the pixel sensor (TESLA p-spray) [6] and the high density interconnect (HDI) flex circuit [1][3] that is capable of supporting eight readout ICs. The characterization of the pixel multichip module prototype as well as the baseline design of the eight chip pixel module and its capabilities are presented. These prototypes were characterized for threshold and noise dispersion. The bump-bonds of the pixel module were examined using an X-ray inspection system. Furthermore, the connectivity of the bump-bonds was tested using a radioactive source ({sup 90}Sr), while the absolute calibration of the modules was achieved using an X-ray source. This paper provides a view of the integration of the three components that together comprise the pixel multichip module.

  2. Micro-Pixel Image Position Sensing Testbed

    NASA Technical Reports Server (NTRS)

    Nemati, Bijan; Shao, Michael; Zhai, Chengxing; Erlig, Hernan; Wang, Xu; Goullioud, Renaud

    2011-01-01

    The search for Earth-mass planets in the habitable zones of nearby Sun-like stars is an important goal of astrophysics. This search is not feasible with the current slate of astronomical instruments. We propose a new concept for microarcsecond astrometry which uses a simplified instrument and hence promises to be low cost. The concept employs a telescope with only a primary, laser metrology applied to the focal plane array, and new algorithms for measuring image position and displacement on the focal plane. The required level of accuracy in both the metrology and image position sensing is at a few micro-pixels. We have begun a detailed investigation of the feasibility of our approach using simulations and a micro-pixel image position sensing testbed called MCT. So far we have been able to demonstrate that the pixel-to-pixel distances in a focal plane can be measured with a precision of 20 micro-pixels and image-to-image distances with a precision of 30 micro-pixels. We have also shown using simulations that our image position algorithm can achieve accuracy of 4 micro-pixels in the presence of lambda/20 wavefront errors.

  3. It's not the pixel count, you fool

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    2012-01-01

    The first thing a "marketing guy" asks the digital camera engineer is "how many pixels does it have, for we need as many mega pixels as possible since the other guys are killing us with their "umpteen" mega pixel pocket sized digital cameras. And so it goes until the pixels get smaller and smaller in order to inflate the pixel count in the never-ending pixel-wars. These small pixels just are not very good. The truth of the matter is that the most important feature of digital cameras in the last five years is the automatic motion control to stabilize the image on the sensor along with some very sophisticated image processing. All the rest has been hype and some "cool" design. What is the future for digital imaging and what will drive growth of camera sales (not counting the cell phone cameras which totally dominate the market in terms of camera sales) and more importantly after sales profits? Well sit in on the Dark Side of Color and find out what is being done to increase the after sales profits and don't be surprised if has been done long ago in some basement lab of a photographic company and of course, before its time.

  4. Activation of matrix metalloproteinase-26 by HOXA10 promotes embryo adhesion in vitro.

    PubMed

    Jiang, Yue; Yan, Guijun; Zhang, Hui; Shan, Huizhi; Kong, Chengcai; Yan, Qiang; Xue, Bai; Diao, Zhenyu; Hu, Yali; Sun, Haixiang

    2014-03-14

    Successful embryonic implantation requires an effective maternal-embryonic molecular dialogue. However, the detailed mechanisms of epithelial-embryo adhesion remain poorly understood. Here, we report that matrix metalloproteinase-26 (MMP-26) is a novel downstream target gene of homeobox a 10 (HOXA10) in human endometrial cells. HOXA10 binds directly to a conserved TTAT unit (-442 to -439) located within the 5' regulatory region of the MMP-26 gene and regulates the expression and secretion of MMP-26 in a concentration-dependent manner. Moreover, the adenovirus-mediated overexpression of MMP-26 in Ishikawa cells markedly increased BeWo spheroid adhesion. An antibody blocking assay further demonstrated that the promotion of BeWo spheroid adhesion by HOXA10 and MMP-26 was significantly inhibited by pre-treatment with a specific antibody against MMP-26. These results demonstrate that the HOXA10-mediated expression of MMP-26 promotes embryo adhesion during the process of embryonic implantation. PMID:24565841

  5. Photovoltaic Pixels for Neural Stimulation: Circuit Models and Performance.

    PubMed

    Boinagrov, David; Lei, Xin; Goetz, Georges; Kamins, Theodore I; Mathieson, Keith; Galambos, Ludwig; Harris, James S; Palanker, Daniel

    2016-02-01

    Photovoltaic conversion of pulsed light into pulsed electric current enables optically-activated neural stimulation with miniature wireless implants. In photovoltaic retinal prostheses, patterns of near-infrared light projected from video goggles onto subretinal arrays of photovoltaic pixels are converted into patterns of current to stimulate the inner retinal neurons. We describe a model of these devices and evaluate the performance of photovoltaic circuits, including the electrode-electrolyte interface. Characteristics of the electrodes measured in saline with various voltages, pulse durations, and polarities were modeled as voltage-dependent capacitances and Faradaic resistances. The resulting mathematical model of the circuit yielded dynamics of the electric current generated by the photovoltaic pixels illuminated by pulsed light. Voltages measured in saline with a pipette electrode above the pixel closely matched results of the model. Using the circuit model, our pixel design was optimized for maximum charge injection under various lighting conditions and for different stimulation thresholds. To speed discharge of the electrodes between the pulses of light, a shunt resistor was introduced and optimized for high frequency stimulation.

  6. Active mechanical coupling between the nucleus, cytoskeleton and the extracellular matrix, and the implications for perinuclear actomyosin organization.

    PubMed

    Zemel, Assaf

    2015-03-28

    Experimental and theoretical studies have demonstrated that the polarization of actomyosin forces in the cytoskeleton of adherent cells is governed by local elastic stresses. Based on this phenomenon, and the established observation that the nucleus is mechanically connected to the extracellular matrix (ECM) via the cytoskeleton, we theoretically analyze here the active mechanical coupling between the nucleus, cytoskeleton and the ECM. The cell is modeled as an active spherical inclusion, containing a round nucleus at its center, and embedded in a 3D elastic matrix. We investigate three sources of cellular stress: spreading-induced stress, actomyosin contractility and chromatin entropic forces. Formulating the coupling of actomyosin contractility to the local stress we predict the consequences that the nucleus, cytoskeleton and ECM mechanical properties may have on the overall force-balance in the cell and the perinuclear acto-myosin polarization. We demonstrate that the presence of the nucleus induces symmetry breaking of the elastic stress that, we predict, elastically tends to orient actomyosin alignment tangentially around the nucleus; the softer the nucleus or the matrix, the stronger is the preference for tangential alignment. Spreading induced stresses may induce radial actomyosin alignment near stiff nuclei. In addition, we show that in regions of high actomyosin density myosin motors have an elastic tendency to orient tangentially as often occurs near the cell periphery. These conclusions highlight the role of the nucleus in the regulation of cytoskeleton organization and may provide new insight into the mechanics of stem cell differentiation involving few fold increase in nucleus stiffness. PMID:25652010

  7. LISe pixel detector for neutron imaging

    NASA Astrophysics Data System (ADS)

    Herrera, Elan; Hamm, Daniel; Wiggins, Brenden; Milburn, Rob; Burger, Arnold; Bilheux, Hassina; Santodonato, Louis; Chvala, Ondrej; Stowe, Ashley; Lukosi, Eric

    2016-10-01

    Semiconducting lithium indium diselenide, 6LiInSe2 or LISe, has promising characteristics for neutron detection applications. The 95% isotopic enrichment of 6Li results in a highly efficient thermal neutron-sensitive material. In this study, we report on a proof-of-principle investigation of a semiconducting LISe pixel detector to demonstrate its potential as an efficient neutron imager. The LISe pixel detector had a 4×4 of pixels with a 550 μm pitch on a 5×5×0.56 mm3 LISe substrate. An experimentally verified spatial resolution of 300 μm was observed utilizing a super-sampling technique.

  8. Per-Pixel Lighting Data Analysis

    SciTech Connect

    Inanici, Mehlika

    2005-08-01

    This report presents a framework for per-pixel analysis of the qualitative and quantitative aspects of luminous environments. Recognizing the need for better lighting analysis capabilities and appreciating the new measurement abilities developed within the LBNL Lighting Measurement and Simulation Toolbox, ''Per-pixel Lighting Data Analysis'' project demonstrates several techniques for analyzing luminance distribution patterns, luminance ratios, adaptation luminance and glare assessment. The techniques are the syntheses of the current practices in lighting design and the unique practices that can be done with per-pixel data availability. Demonstrated analysis techniques are applicable to both computer-generated and digitally captured images (physically-based renderings and High Dynamic Range photographs).

  9. Factor H-related protein 5 interacts with pentraxin 3 and the extracellular matrix and modulates complement activation.

    PubMed

    Csincsi, Ádám I; Kopp, Anne; Zöldi, Miklós; Bánlaki, Zsófia; Uzonyi, Barbara; Hebecker, Mario; Caesar, Joseph J E; Pickering, Matthew C; Daigo, Kenji; Hamakubo, Takao; Lea, Susan M; Goicoechea de Jorge, Elena; Józsi, Mihály

    2015-05-15

    The physiological roles of the factor H (FH)-related proteins are controversial and poorly understood. Based on genetic studies, FH-related protein 5 (CFHR5) is implicated in glomerular diseases, such as atypical hemolytic uremic syndrome, dense deposit disease, and CFHR5 nephropathy. CFHR5 was also identified in glomerular immune deposits at the protein level. For CFHR5, weak complement regulatory activity and competition for C3b binding with the plasma complement inhibitor FH have been reported, but its function remains elusive. In this study, we identify pentraxin 3 (PTX3) as a novel ligand of CFHR5. Binding of native CFHR5 to PTX3 was detected in human plasma and the interaction was characterized using recombinant proteins. The binding of PTX3 to CFHR5 is of ∼2-fold higher affinity compared with that of FH. CFHR5 dose-dependently inhibited FH binding to PTX3 and also to the monomeric, denatured form of the short pentraxin C-reactive protein. Binding of PTX3 to CFHR5 resulted in increased C1q binding. Additionally, CFHR5 bound to extracellular matrix in vitro in a dose-dependent manner and competed with FH for binding. Altogether, CFHR5 reduced FH binding and its cofactor activity on pentraxins and the extracellular matrix, while at the same time allowed for enhanced C1q binding. Furthermore, CFHR5 allowed formation of the alternative pathway C3 convertase and supported complement activation. Thus, CFHR5 may locally enhance complement activation via interference with the complement-inhibiting function of FH, by enhancement of C1q binding, and by activating complement, thereby contributing to glomerular disease.

  10. A program of cell death and extracellular matrix degradation is activated in the amnion before the onset of labor.

    PubMed Central

    Lei, H; Furth, E E; Kalluri, R; Chiou, T; Tilly, K I; Tilly, J L; Elkon, K B; Jeffrey, J J; Strauss, J F

    1996-01-01

    Fetal membranes usually rupture during the process of labor. Premature fetal membrane rupture occurs not infrequently and is associated with significant fetal and maternal morbidity. The mechanisms of normal and pathologic fetal membrane rupture are not well understood. We have examined structural and biochemical changes in the rat amnion as labor approaches in order to characterize this process in normal pregnancy. Here we report that before the onset of active labor the amnion epithelial cells undergo apoptotic cell death which encompasses degradation of 28S ribosomal subunit RNA and associated P proteins and fragmentation of nuclear DNA. Concurrent with these cellular changes, the amnion type I collagen matrix is degraded with the accumulation of three-quarter length type I collagen fragments in extraembryonic fluid, characteristic of the cleavage of fibrillar collagen by interstitial collagenase. Western blot and immunohistochemical analyses confirmed that interstitial collagenase protein appears in association with the loss of amnion type I collagen. We conclude that amnion epithelial cells undergo a process of programmed cell death associated with orchestrated extracellular matrix degradation which begins before the onset of active labor. Thus, fetal membrane rupture is likely to be the result of biochemical changes as well as physical forces. PMID:8903315

  11. Approach to In- Situ Producing Reinforcing Phase Within an Active-Transient Liquid Phase Bond Seam for Aluminum Matrix Composite

    NASA Astrophysics Data System (ADS)

    Zhang, Guifeng; Liao, Xianjin; Chen, Bo; Zhang, Linjie; Zhang, Jianxun

    2015-06-01

    To optimize the braze composition design route for aluminum matrix composite, the feasibility of in situ producing reinforcing phase within the transient liquid phase bond seam matrix, by adding active melting point increaser (MPI, e.g., Ti) together with general melting point depressant (MPD, e.g., Cu) into the interlayer, was demonstrated. For SiC p /A356 composite, by comparing the wettability, joint microstructure, joint shear strength, and fracture path for the developed Al-19Cu-1Ti, Al-19Cu, Al-33Cu-1Ti, Al-33Cu (wt pct), and commercial Cu foils as interlayer, the feasibility of in situ producing reinforcing phase within the bond seam by adding Ti was demonstrated. Especially for Al-19Cu-1Ti active braze, small and dispersed ternary aluminide of Al-Si-Ti phase was obtained within the bond seam as in situ reinforcement, leading to a favorable fracture path within SiC p /A356, not along the initial interface or within the bond seam. For the formation mechanism of the in situ reinforcing phase of MPI-containing intermetallic compound within the bond seam, a model of repeating concentration-precipitation-termination-engulfment during isothermal solidification is proposed.

  12. Characterization of Xenopus Tissue Inhibitor of Metalloproteinases-2: A Role in Regulating Matrix Metalloproteinase Activity during Development

    PubMed Central

    Fiorentino, Maria; Shi, Yun-Bo

    2012-01-01

    Background Frog metamorphosis is totally dependent on thyroid hormone (T3) and mimics the postembryonic period around birth in mammals. It is an excellent model to study the molecular basis of postembryonic development in vertebrate. We and others have shown that many, if not all, matrix metalloproteinases (MMPs), which cleave proteins of the extracellular matrix as well as other substrates, are induced by T3 and important for metamorphosis. MMP activity can be inhibited by tissue inhibitors of metalloproteinase (TIMPs). There are 4 TIMPs in vertebrates and their roles in postembryonic development are poorly studied. Methodology/Principal Findings We analyzed the TIMP2 genes in Xenopus laevis and the highly related species Xenopus tropicalis and discovered that TIMP2 is a single copy gene in Xenopus tropicalis as in mammals but is duplicated in Xenopus laevis. Furthermore, the TIMP2 locus in Xenopus tropicalis genome is different from that in human, suggesting an evolutionary reorganization of the locus. More importantly, we found that the duplicated TIMP2 genes were similarly regulated in the developing limb, remodeling intestine, resorbing tail during metamorphosis. Unexpectedly, like its MMP target genes, the TIMP2 genes were upregulated by T3 during both natural and T3-induced metamorphosis. Conclusions/Significance Our results indicate that TIMP2 is highly conserved among vertebrates and that the TIMP2 locus underwent a chromosomal reorganization during evolution. Furthermore, the unexpected upregulation of TIMP2 genes during metamorphosis suggests that proper balance of MMP activity is important for metamorphosis. PMID:22693555

  13. Tumor necrosis factor-alpha induced expression of matrix metalloproteinase-9 through p21-activated Kinase-1

    PubMed Central

    Zhou, Ling; Yan, Chunli; Gieling, Roben G; Kida, Yujiro; Garner, Warren; Li, Wei; Han, Yuan-Ping

    2009-01-01

    Background Expressed in embryonic development, matrix metalloprotein-9 (MMP-9) is absent in most of developed adult tissues, but recurs in inflammation during tissue injury, wound healing, tumor formation and metastasis. Expression of MMP-9 is tightly controlled by extracellular cues including pro-inflammatory cytokines and extracellular matrix (ECM). While the pathologic functions of MMP-9 are evident, the intracellular signaling pathways to control its expression are not fully understood. In this study we investigated mechanism of cytokine induced MMP-9 with particular emphasis on the role of p21-activated-kinase-1 (PAK1) and the down stream signaling. Results In response to TNF-alpha or IL-1alpha, PAK1 was promptly activated, as characterized by a sequential phosphorylation, initiated at threonine-212 followed by at threonine-423 in the activation loop of the kinase, in human skin keratinocytes, dermal fibroblasts, and rat hepatic stellate cells. Ectopic expression of PAK1 variants, but not p38 MAP kinase, impaired the TNF-alpha-induced MMP-9 expression, while other MMPs such as MMP-2, -3 and -14 were not affected. Activation of Jun N-terminal kinase (JNK) and NF-kappaB has been demonstrated to be essential for MMP-9 expression. Expression of inactive PAK1 variants impaired JNK but not NF-kappaB activation, which consequently suppressed the 5'-promoter activities of the MMP-9 gene. After the cytokine-induced phosphorylation, both ectopically expressed and endogenous PAK1 proteins were promptly accumulated even in the condition of suppressing protein synthesis, suggesting the PAK1 protein is stabilized upon TNF-alpha stimulation. Stabilization of PAK1 protein by TNF-alpha treatment is independent of the kinase catalytic activity and p21 GTPase binding capacities. In contrast to epithelial cells, mesenchymal cells require 3-dimensional type-I collagen in response to TNF-alpha to massively express MMP-9. The collagen effect is mediated, in part, by boost JNK

  14. Influenza matrix protein 2 alters CFTR expression and function through its ion channel activity.

    PubMed

    Londino, James D; Lazrak, Ahmed; Jurkuvenaite, Asta; Collawn, James F; Noah, James W; Matalon, Sadis

    2013-05-01

    The human cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-activated chloride (Cl(-)) channel in the lung epithelium that helps regulate the thickness and composition of the lung epithelial lining fluid. We investigated whether influenza M2 protein, a pH-activated proton (H(+)) channel that traffics to the plasma membrane of infected cells, altered CFTR expression and function. M2 decreased CFTR activity in 1) Xenopus oocytes injected with human CFTR, 2) epithelial cells (HEK-293) stably transfected with CFTR, and 3) human bronchial epithelial cells (16HBE14o-) expressing native CFTR. This inhibition was partially reversed by an inhibitor of the ubiquitin-activating enzyme E1. Next we investigated whether the M2 inhibition of CFTR activity was due to an increase of secretory organelle pH by M2. Incubation of Xenopus oocytes expressing CFTR with ammonium chloride or concanamycin A, two agents that alkalinize the secretory pathway, inhibited CFTR activity in a dose-dependent manner. Treatment of M2- and CFTR-expressing oocytes with the M2 ion channel inhibitor amantadine prevented the loss in CFTR expression and activity; in addition, M2 mutants, lacking the ability to transport H(+), did not alter CFTR activity in Xenopus oocytes and HEK cells. Expression of an M2 mutant retained in the endoplasmic reticulum also failed to alter CFTR activity. In summary, our data show that M2 decreases CFTR activity by increasing secretory organelle pH, which targets CFTR for destruction by the ubiquitin system. Alteration of CFTR activity has important consequences for fluid regulation and may potentially modify the immune response to viral infection.

  15. Influenza matrix protein 2 alters CFTR expression and function through its ion channel activity

    PubMed Central

    Londino, James D.; Lazrak, Ahmed; Jurkuvenaite, Asta; Collawn, James F.; Noah, James W.

    2013-01-01

    The human cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-activated chloride (Cl−) channel in the lung epithelium that helps regulate the thickness and composition of the lung epithelial lining fluid. We investigated whether influenza M2 protein, a pH-activated proton (H+) channel that traffics to the plasma membrane of infected cells, altered CFTR expression and function. M2 decreased CFTR activity in 1) Xenopus oocytes injected with human CFTR, 2) epithelial cells (HEK-293) stably transfected with CFTR, and 3) human bronchial epithelial cells (16HBE14o−) expressing native CFTR. This inhibition was partially reversed by an inhibitor of the ubiquitin-activating enzyme E1. Next we investigated whether the M2 inhibition of CFTR activity was due to an increase of secretory organelle pH by M2. Incubation of Xenopus oocytes expressing CFTR with ammonium chloride or concanamycin A, two agents that alkalinize the secretory pathway, inhibited CFTR activity in a dose-dependent manner. Treatment of M2- and CFTR-expressing oocytes with the M2 ion channel inhibitor amantadine prevented the loss in CFTR expression and activity; in addition, M2 mutants, lacking the ability to transport H+, did not alter CFTR activity in Xenopus oocytes and HEK cells. Expression of an M2 mutant retained in the endoplasmic reticulum also failed to alter CFTR activity. In summary, our data show that M2 decreases CFTR activity by increasing secretory organelle pH, which targets CFTR for destruction by the ubiquitin system. Alteration of CFTR activity has important consequences for fluid regulation and may potentially modify the immune response to viral infection. PMID:23457187

  16. Activation of toll-like receptor-2 by endogenous matrix metalloproteinase-2 modulates dendritic-cell-mediated inflammatory responses.

    PubMed

    Godefroy, Emmanuelle; Gallois, Anne; Idoyaga, Juliana; Merad, Miriam; Tung, Navpreet; Monu, Ngozi; Saenger, Yvonne; Fu, Yichun; Ravindran, Rajesh; Pulendran, Bali; Jotereau, Francine; Trombetta, Sergio; Bhardwaj, Nina

    2014-12-11

    Matrix metalloproteinase-2 (MMP-2) is involved in several physiological mechanisms, including wound healing and tumor progression. We show that MMP-2 directly stimulates dendritic cells (DCs) to both upregulate OX40L on the cell surface and secrete inflammatory cytokines. The mechanism underlying DC activation includes physical association with Toll-like receptor-2 (TLR2), leading to NF-κB activation, OX40L upregulation on DCs, and ensuing TH2 differentiation. Significantly, MMP-2 polarizes T cells toward type 2 responses in vivo, in a TLR2-dependent manner. MMP-2-dependent type 2 polarization may represent a key immune regulatory mechanism for protection against a broad array of disorders, such as inflammatory, infectious, and autoimmune diseases, which can be hijacked by tumors to evade immunity.

  17. Activation of Toll-like receptor-2 by endogenous matrix metalloproteinase-2 modulates dendritic cell-mediated inflammatory responses

    PubMed Central

    Godefroy, Emmanuelle; Gallois, Anne; Idoyaga, Juliana; Merad, Miriam; Tung, Navpreet; Monu, Ngozi; Saenger, Yvonne; Fu, Yichun; Nair, Rajesh; Pulendran, Bali; Jotereau, Francine; Trombetta, Sergio; Bhardwaj, Nina

    2015-01-01

    SUMMARY Matrix metalloproteinase-2 (MMP-2) is involved in several physiological mechanisms, including wound healing and tumor progression. We show that MMP-2 directly stimulates dendritic cells (DCs) to both up-regulate OX40L on the cell surface and secrete inflammatory cytokines. The mechanism underlying DC activation includes physical association with Toll-like receptor-2 (TLR2), leading to NF-κB activation, OX40L up-regulation on DCs and ensuing TH2 differentiation. Significantly, MMP-2 polarizes T cells towards type-2 responses in vivo, in a TLR2-dependent manner. MMP-2-dependent type-2 polarization may represent a key immune regulatory mechanism to protect against a broad array of disorders, such as inflammatory, infectious and autoimmune diseases, which can be hijacked by tumors to evade immunity. PMID:25466255

  18. An 8-bit Data Driving Scheme Based on Two-Step Digital-to-Analog Conversion for Integrated Data Drivers of Active-Matrix Organic Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Wook; Choi, Byong-Deok

    2012-03-01

    The two-step digital-to-analog conversion (DAC) scheme has been reported to be very area-efficient for thin-film transistor-liquid crystal display (TFT-LCD) data driver ICs, but it is not as well suited as it is for polycrystalline silicon (poly-Si) TFT integrated circuits. The charge redistribution in the two-step DAC process requires an operational amplifier in principle, which is most challenging for poly-Si TFT circuits. The proposed two-step DAC for active-matrix organic light-emitting diodes (AMOLEDs) makes the operational amplifier unnecessary by appropriately exploiting the preexisting capacitors in the pixel to compensate for the characteristic variations of TFTs. Moreover, the second-step DAC occurs at the same time as threshold voltage compensation, and it does not require additional time. By thoroughly analyzing area efficiency depending on the resolution decomposition between the first- and second-step DACs, we found that 5-bit coarse plus 3-bit fine DACs are best in terms of circuit area. When we designed a layout of the proposed 8-bit DAC on the basis of the 4 µm design rules, the DAC circuit area is no more than 72×637 µm2, which, to the best of our knowledge, is the most compact to date.

  19. Ratio of Active Matrix Metalloproteinases and Proenzymes during Growth and Metastasizing of Mouse Lewis Lung Adenocarcinoma.

    PubMed

    Kisarova, Ya A; Kaledin, V I; Bogdanova, L A; Korolenko, T A

    2015-08-01

    Ratio between proMMP and active MMP was studied in the dynamics of growth of the Lewis lung adenocarcinoma with lung metastasis. It was shown that tumor growth is associated with an increase in the content of proMMP (day 20; terminal stage), but the level of active MMP in tumor tissue did not signifi cantly change. The development of lung metastasis was accompanied by accumulation of active MMP (days 7, 15, and 20) and a decrease in the content of pro-MMP (days 7, and 20) in comparison with the control. In the spleen of these mice (metastasis-free organ), an increase in the levels of proMMP (day 20) and especially active MMP (days 7, 15, and 20) were found. The results suggest that tumor development shifts the proportion between active MMP and proenzymes in the tumor, lungs with metastasis, and spleen without metastasis. PMID:26392281

  20. Ratio of Active Matrix Metalloproteinases and Proenzymes during Growth and Metastasizing of Mouse Lewis Lung Adenocarcinoma.

    PubMed

    Kisarova, Ya A; Kaledin, V I; Bogdanova, L A; Korolenko, T A

    2015-08-01

    Ratio between proMMP and active MMP was studied in the dynamics of growth of the Lewis lung adenocarcinoma with lung metastasis. It was shown that tumor growth is associated with an increase in the content of proMMP (day 20; terminal stage), but the level of active MMP in tumor tissue did not signifi cantly change. The development of lung metastasis was accompanied by accumulation of active MMP (days 7, 15, and 20) and a decrease in the content of pro-MMP (days 7, and 20) in comparison with the control. In the spleen of these mice (metastasis-free organ), an increase in the levels of proMMP (day 20) and especially active MMP (days 7, 15, and 20) were found. The results suggest that tumor development shifts the proportion between active MMP and proenzymes in the tumor, lungs with metastasis, and spleen without metastasis.

  1. Pixels, Imagers and Related Fabrication Methods

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

    2016-01-01

    Pixels, imagers and related fabrication methods are described. The described methods result in cross-talk reduction in imagers and related devices by generating depletion regions. The devices can also be used with electronic circuits for imaging applications.

  2. Pixels, Imagers and Related Fabrication Methods

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

    2014-01-01

    Pixels, imagers and related fabrication methods are described. The described methods result in cross-talk reduction in imagers and related devices by generating depletion regions. The devices can also be used with electronic circuits for imaging applications.

  3. Design of the small pixel pitch ROIC

    NASA Astrophysics Data System (ADS)

    Liang, Qinghua; Jiang, Dazhao; Chen, Honglei; Zhai, Yongcheng; Gao, Lei; Ding, Ruijun

    2014-11-01

    Since the technology trend of the third generation IRFPA towards resolution enhancing has steadily progressed,the pixel pitch of IRFPA has been greatly reduced.A 640×512 readout integrated circuit(ROIC) of IRFPA with 15μm pixel pitch is presented in this paper.The 15μm pixel pitch ROIC design will face many challenges.As we all known,the integrating capacitor is a key performance parameter when considering pixel area,charge capacity and dynamic range,so we adopt the effective method of 2 by 2 pixels sharing an integrating capacitor to solve this problem.The input unit cell architecture will contain two paralleled sample and hold parts,which not only allow the FPA to be operated in full frame snapshot mode but also save relatively unit circuit area.Different applications need more matching input unit circuits. Because the dimension of 2×2 pixels is 30μm×30μm, an input stage based on direct injection (DI) which has medium injection ratio and small layout area is proved to be suitable for middle wave (MW) while BDI with three-transistor cascode amplifier for long wave(LW). By adopting the 0.35μm 2P4M mixed signal process, the circuit architecture can make the effective charge capacity of 7.8Me- per pixel with 2.2V output range for MW and 7.3 Me- per pixel with 2.6V output range for LW. According to the simulation results, this circuit works well under 5V power supply and achieves less than 0.1% nonlinearity.

  4. Simulation on the Charged Particle Response of the STAR Heavy Flavor Tracker Pixel Detector

    NASA Astrophysics Data System (ADS)

    Cimaroli, Alex; Li, Xin

    2009-10-01

    The main task of the STAR experiment, located at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, is to study the quark-gluon plasma (QGP), which is believed to have been created a few microseconds after the ``Big Bang.'' Heavy quarks are ideal tools for studying the properties of QGP. The Heavy Flavor Tracker (HFT) is the central part of the STAR future heavy flavor physics program and will enable STAR to directly measure heavy flavor mesons. The core of HFT is a pixel detector (PIXEL) using CMOS Active PIXEL Sensor. This poster will describe the development of a detailed simulation of the pixel detector response to charged particles and the corresponding fast simulation that dramatically enhances the simulation speed with little sacrifice in accuracy. The full simulation randomly generates ionized electrons along an incoming track and diffuses the electrons inside the pixel array until they are collected by the electronics or recombined inside a pixel. With the same result, the fast simulation, which quickens processing time from one hour to 5 seconds, generates a grid inside a single pixel and create a map of probability distribution functions for a single ionized electron generated from a grid point. We will also discuss the study of pixel detector position resolution using a simple clustering algorithm.

  5. Recent development of ultra small pixel uncooled focal plane arrays at DRS

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Skidmore, George D.; Howard, Christopher; Han, C. J.; Wood, Lewis; Peysha, Doug; Williams, Eric; Trujillo, Carlos; Emmett, Jeff; Robas, Gary; Jardine, Daniel; Wan, C.-F.; Clarke, Elwood

    2007-04-01

    DRS is a major supplier of the 25μm pixel pitch 640x480 and 320x240 infrared uncooled focal plane arrays (UFPAs) and camera products for commercial and military markets. The state-of-the-art 25μm pixel focal plane arrays currently in production provide excellent performance for soldier thermal weapon sights (TWS), vehicle driver vision enhancers (DVE), and aerial surveillance and industrial thermograph applications. To further improve sensor resolution and reduce the sensor system size, weight and cost, it is highly desired to reduce the UFPA pixel size. However, the 17μm pixel FPA presents significant design and fabrication challenges as compared with 25μm pixel FPAs. The design objectives, engineering trade-offs, and performance goals will be discussed. This paper presents an overview of the 17μm microblometer uncooled focal plane arrays and sensor electronics production and development activities at DRS. The 17 μm pixel performance data from several initial fabrication lots will be summarized. Relevant 25μm pixel performance data are provided for comparison. Thermal images and video from the 17μm pixel 640x480 UFPA will also be presented.

  6. 18k Channels single photon counting readout circuit for hybrid pixel detector

    NASA Astrophysics Data System (ADS)

    Maj, P.; Grybos, P.; Szczygiel, R.; Zoladz, M.; Sakumura, T.; Tsuji, Y.

    2013-01-01

    We have performed measurements of an integrated circuit named PXD18k designed for hybrid pixel semiconductor detectors used in X-ray imaging applications. The PXD18k integrated circuit, fabricated in CMOS 180 nm technology, has dimensions of 9.64 mm×20 mm and contains approximately 26 million transistors. The core of the IC is a matrix of 96×192 pixels with 100 μm×100 μm pixel size. Each pixel works in a single photon counting mode. A single pixel contains two charge sensitive amplifiers with Krummenacher feedback scheme, two shapers, two discriminators (with independent thresholds A and B) and two 16-bit ripple counters. The data are read out via eight low voltage differential signaling (LVDS) outputs with 100 Mbps rate. The power consumption is dominated by analog blocks and it is about 23 μW/pixel. The effective peaking time at the discriminator input is 30 ns and is mainly determined by the time constants of the charge sensitive amplifier (CSA). The gain is equal to 42.5 μV/e- and the equivalent noise charge is 168 e- rms (with bump-bonded silicon pixel detector). Thanks to the use of trim DACs in each pixel, the effective threshold spread at the discriminator input is only 1.79 mV. The dead time of the front end electronics for a standard setting is 172 ns (paralyzable model). In the standard readout mode (when the data collection time is separated from the time necessary to readout data from the chip) the PXD18k IC works with two energy thresholds per pixel. The PXD18k can also be operated in the continuous readout mode (with a zero dead time) where one can select the number of bits readout from each pixel to optimize the PXD18k frame rate. For example, for reading out 16 bits/pixel the frame rate is 2.7 kHz and for 4 bits/pixel it rises to 7.1 kHz.

  7. Characterisation of crystal matrices and single pixels for nuclear medicine applications

    NASA Astrophysics Data System (ADS)

    Herbert, D. J.; Belcari, N.; Camarda, M.; Guerra, A. Del; Vaiano, A.

    2005-01-01

    Commercially constructed crystal matrices are characterised for use with PSPMT detectors for PET system developments and other nuclear medicine applications. The matrices of different scintillation materials were specified with pixel dimensions of 1.5×1.5 mm2 in cross-section and a length corresponding to one gamma ray interaction length at 511 keV. The materials used in this study were BGO, LSO, LYSO, YSO and CsI(Na). Each matrix was constructed using a white TiO loaded epoxy that forms a 0.2 mm septa between each pixel. The white epoxy is not the optimum choice in terms of the reflective properties, but represents a good compromise between cost and the need for optical isolation between pixels. We also tested a YAP matrix that consisted of pixels of the same size specification but was manufactured by a different company, who instead of white epoxy, used a thin aluminium reflective layer for optical isolation that resulted in a septal thickness of just 0.01 mm, resulting in a much higher packing fraction. The characteristics of the scintillation materials, such as the light output and energy resolution, were first studied in the form of individual crystal elements by using a single pixel HPD. A comparison of individual pixels with and without the epoxy/dielectric coatings was also performed. Then the matrices themselves were coupled to a PSPMT in order to study the imaging performance. In particular, the system pixel resolution and the peak to valley ratio were measured at 511 and 122 keV.

  8. The Dosepix detector—an energy-resolving photon-counting pixel detector for spectrometric measurements

    NASA Astrophysics Data System (ADS)

    Zang, A.; Anton, G.; Ballabriga, R.; Bisello, F.; Campbell, M.; Celi, J. C.; Fauler, A.; Fiederle, M.; Jensch, M.; Kochanski, N.; Llopart, X.; Michel, N.; Mollenhauer, U.; Ritter, I.; Tennert, F.; Wölfel, S.; Wong, W.; Michel, T.

    2015-04-01

    The Dosepix detector is a hybrid photon-counting pixel detector based on ideas of the Medipix and Timepix detector family. 1 mm thick cadmium telluride and 300 μm thick silicon were used as sensor material. The pixel matrix of the Dosepix consists of 16 x 16 square pixels with 12 rows of (200 μm)2 and 4 rows of (55 μm)2 sensitive area for the silicon sensor layer and 16 rows of pixels with 220 μm pixel pitch for CdTe. Besides digital energy integration and photon-counting mode, a novel concept of energy binning is included in the pixel electronics, allowing energy-resolved measurements in 16 energy bins within one acquisition. The possibilities of this detector concept range from applications in personal dosimetry and energy-resolved imaging to quality assurance of medical X-ray sources by analysis of the emitted photon spectrum. In this contribution the Dosepix detector, its response to X-rays as well as spectrum measurements with Si and CdTe sensor layer are presented. Furthermore, a first evaluation was carried out to use the Dosepix detector as a kVp-meter, that means to determine the applied acceleration voltage from measured X-ray tubes spectra.

  9. Steganography based on pixel intensity value decomposition

    NASA Astrophysics Data System (ADS)

    Abdulla, Alan Anwar; Sellahewa, Harin; Jassim, Sabah A.

    2014-05-01

    This paper focuses on steganography based on pixel intensity value decomposition. A number of existing schemes such as binary, Fibonacci, Prime, Natural, Lucas, and Catalan-Fibonacci (CF) are evaluated in terms of payload capacity and stego quality. A new technique based on a specific representation is proposed to decompose pixel intensity values into 16 (virtual) bit-planes suitable for embedding purposes. The proposed decomposition has a desirable property whereby the sum of all bit-planes does not exceed the maximum pixel intensity value, i.e. 255. Experimental results demonstrate that the proposed technique offers an effective compromise between payload capacity and stego quality of existing embedding techniques based on pixel intensity value decomposition. Its capacity is equal to that of binary and Lucas, while it offers a higher capacity than Fibonacci, Prime, Natural, and CF when the secret bits are embedded in 1st Least Significant Bit (LSB). When the secret bits are embedded in higher bit-planes, i.e., 2nd LSB to 8th Most Significant Bit (MSB), the proposed scheme has more capacity than Natural numbers based embedding. However, from the 6th bit-plane onwards, the proposed scheme offers better stego quality. In general, the proposed decomposition scheme has less effect in terms of quality on pixel value when compared to most existing pixel intensity value decomposition techniques when embedding messages in higher bit-planes.

  10. Sensor development for the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Bolla, G.; Bortoletto, D.; Horisberger, R.; Kaufmann, R.; Rohe, T.; Roy, A.

    2002-06-01

    The CMS experiment which is currently under construction at the Large Hadron Collider (LHC) at CERN (Geneva, Switzerland) will contain a pixel detector which provides in its final configuration three space points per track close to the interaction point of the colliding beams. Because of the harsh radiation environment of the LHC, the technical realization of the pixel detector is extremely challenging. The readout chip as the most damageable part of the system is believed to survive a particle fluence of 6×10 14 neq/ cm2 (All fluences are normalized to 1 MeV neutrons and therefore all components of the hybrid pixel detector have to perform well up to at least this fluence. As this requires a partially depleted operation of the silicon sensors after irradiation-induced type inversion of the substrate, an "n in n" concept has been chosen. In order to perform IV-tests on wafer level and to hold accidentally unconnected pixels close to ground potential, a resistive path between the pixels has been implemented by the openings in the p-stop implants surrounding every pixel cell. A prototype of such sensors has been produced by two different companies and especially the properties of these resistors have extensively been tested before and after irradiation.

  11. Small pixel oversampled IR focal plane arrays

    NASA Astrophysics Data System (ADS)

    Caulfield, John; Curzan, Jon; Lewis, Jay; Dhar, Nibir

    2015-06-01

    We report on a new high definition high charge capacity 2.1 Mpixel MWIR Infrared Focal Plane Array. This high definition (HD) FPA utilizes a small 5 um pitch pixel size which is below the Nyquist limit imposed by the optical systems Point Spread Function (PSF). These smaller sub diffraction limited pixels allow spatial oversampling of the image. We show that oversampling IRFPAs enables improved fidelity in imaging including resolution improvements, advanced pixel correlation processing to reduce false alarm rates, improved detection ranges, and an improved ability to track closely spaced objects. Small pixel HD arrays are viewed as the key component enabling lower size, power and weight of the IR Sensor System. Small pixels enables a reduction in the size of the systems components from the smaller detector and ROIC array, the reduced optics focal length and overall lens size, resulting in an overall compactness in the sensor package, cooling and associated electronics. The highly sensitive MWIR small pixel HD FPA has the capability to detect dimmer signals at longer ranges than previously demonstrated.

  12. Focal plane array with modular pixel array components for scalability

    DOEpatents

    Kay, Randolph R; Campbell, David V; Shinde, Subhash L; Rienstra, Jeffrey L; Serkland, Darwin K; Holmes, Michael L

    2014-12-09

    A modular, scalable focal plane array is provided as an array of integrated circuit dice, wherein each die includes a given amount of modular pixel array circuitry. The array of dice effectively multiplies the amount of modular pixel array circuitry to produce a larger pixel array without increasing die size. Desired pixel pitch across the enlarged pixel array is preserved by forming die stacks with each pixel array circuitry die stacked on a separate die that contains the corresponding signal processing circuitry. Techniques for die stack interconnections and die stack placement are implemented to ensure that the desired pixel pitch is preserved across the enlarged pixel array.

  13. Evolution of a supercooled Ice Shelf Water plume with an actively growing subice platelet matrix

    NASA Astrophysics Data System (ADS)

    Robinson, Natalie J.; Williams, Michael J. M.; Stevens, Craig L.; Langhorne, Patricia J.; Haskell, Timothy G.

    2014-06-01

    We use new observations in Western McMurdo Sound, combined with longitudinal hydrographic transects of the sound, to identify a northward-flowing Ice Shelf Water (ISW) plume exiting the cavity of the McMurdo-Ross Ice Shelf. We estimate the plume's net northward transport at 0.4 ± 0.1 Sv, carving out a corridor approximately 35 km wide aligned with the Victoria Land Coast. Basal topography of the McMurdo Ice Shelf is such that the plume is delivered to the surface without mixing with overlying warmer water, and is therefore able to remain below the surface freezing temperature at the point of observation beneath first-year ice. Thus, the upper ocean was supercooled, by up to 50 mK at the surface, due to pressure relief from recent rapid ascent of the steep basal slope. The 70 m thick supercooled layer supports the growth and maintenance of a thick, semirigid, and porous matrix of platelet ice, which is trapped by buoyancy at the ice-ocean interface. Continued growth of individual platelets in supercooled water creates significant brine rejection at the top of the water column which resulted in convection over the upper 200 m thick, homogeneous layer. By examining the diffusive nature of the intermediate water between layers of ISW and High Salinity Shelf Water, we conclude that the ISW plume must have originated beneath the Ross Ice Shelf and demonstrate that it is likely to expand eastward across McMurdo Sound with the progression of winter.

  14. Matrix Domain Modulates HIV-1 Gag's Nucleic Acid Chaperone Activity via Inositol Phosphate Binding ▿

    PubMed Central

    Jones, Christopher P.; Datta, Siddhartha A. K.; Rein, Alan; Rouzina, Ioulia; Musier-Forsyth, Karin

    2011-01-01

    Retroviruses replicate by reverse transcribing their single-stranded RNA genomes into double-stranded DNA using specific cellular tRNAs to prime cDNA synthesis. In HIV-1, human tRNA3Lys serves as the primer and is packaged into virions during assembly. The viral Gag protein is believed to chaperone tRNA3Lys placement onto the genomic RNA primer binding site; however, the timing and possible regulation of this event are currently unknown. Composed of the matrix (MA), capsid (CA), nucleocapsid (NC), and p6 domains, the multifunctional HIV-1 Gag polyprotein orchestrates the highly coordinated process of virion assembly, but the contribution of these domains to tRNA3Lys annealing is unclear. Here, we show that NC is absolutely essential for annealing and that the MA domain inhibits Gag's tRNA annealing capability. During assembly, MA specifically interacts with inositol phosphate (IP)-containing lipids in the plasma membrane (PM). Surprisingly, we find that IPs stimulate Gag-facilitated tRNA annealing but do not stimulate annealing in Gag variants lacking the MA domain or containing point mutations involved in PM binding. Moreover, we find that IPs prevent MA from binding to nucleic acids but have little effect on NC or Gag. We propose that Gag binds to RNA either with both NC and MA domains or with NC alone and that MA-IP interactions alter Gag's binding mode. We propose that MA's interactions with the PM trigger the switch between these two binding modes and stimulate Gag's chaperone function, which may be important for the regulation of events such as tRNA primer annealing. PMID:21123373

  15. Hexagonal Pixels and Indexing Scheme for Binary Images

    NASA Technical Reports Server (NTRS)

    Johnson, Gordon G.

    2004-01-01

    A scheme for resampling binaryimage data from a rectangular grid to a regular hexagonal grid and an associated tree-structured pixel-indexing scheme keyed to the level of resolution have been devised. This scheme could be utilized in conjunction with appropriate image-data-processing algorithms to enable automated retrieval and/or recognition of images. For some purposes, this scheme is superior to a prior scheme that relies on rectangular pixels: one example of such a purpose is recognition of fingerprints, which can be approximated more closely by use of line segments along hexagonal axes than by line segments along rectangular axes. This scheme could also be combined with algorithms for query-image-based retrieval of images via the Internet. A binary image on a rectangular grid is generated by raster scanning or by sampling on a stationary grid of rectangular pixels. In either case, each pixel (each cell in the rectangular grid) is denoted as either bright or dark, depending on whether the light level in the pixel is above or below a prescribed threshold. The binary data on such an image are stored in a matrix form that lends itself readily to searches of line segments aligned with either or both of the perpendicular coordinate axes. The first step in resampling onto a regular hexagonal grid is to make the resolution of the hexagonal grid fine enough to capture all the binaryimage detail from the rectangular grid. In practice, this amounts to choosing a hexagonal-cell width equal to or less than a third of the rectangular- cell width. Once the data have been resampled onto the hexagonal grid, the image can readily be checked for line segments aligned with the hexagonal coordinate axes, which typically lie at angles of 30deg, 90deg, and 150deg with respect to say, the horizontal rectangular coordinate axis. Optionally, one can then rotate the rectangular image by 90deg, then again sample onto the hexagonal grid and check for line segments at angles of 0deg, 60deg

  16. Modeling of Pixelated Detector in SPECT Pinhole Reconstruction

    PubMed Central

    Feng, Bing; Zeng, Gengsheng L.

    2014-01-01

    A challenge for the pixelated detector is that the detector response of a gamma-ray photon varies with the incident angle and the incident location within a crystal. The normalization map obtained by measuring the flood of a point-source at a large distance can lead to artifacts in reconstructed images. In this work, we investigated a method of generating normalization maps by ray-tracing through the pixelated detector based on the imaging geometry and the photo-peak energy for the specific isotope. The normalization is defined for each pinhole as the normalized detector response for a point-source placed at the focal point of the pinhole. Ray-tracing is used to generate the ideal flood image for a point-source. Each crystal pitch area on the back of the detector is divided into 60 × 60 sub-pixels. Lines are obtained by connecting between a point-source and the centers of sub-pixels inside each crystal pitch area. For each line ray-tracing starts from the entrance point at the detector face and ends at the center of a sub-pixel on the back of the detector. Only the attenuation by NaI(Tl) crystals along each ray is assumed to contribute directly to the flood image. The attenuation by the silica (SiO2) reflector is also included in the ray-tracing. To calculate the normalization for a pinhole, we need to calculate the ideal flood for a point-source at 360 mm distance (where the point-source was placed for the regular flood measurement) and the ideal flood image for the point-source at the pinhole focal point, together with the flood measurement at 360 mm distance. The normalizations are incorporated in the iterative OSEM reconstruction as a component of the projection matrix. Applications to single-pinhole and multi-pinhole imaging showed that this method greatly reduced the reconstruction artifacts. PMID:25574058

  17. Activities of matrix metalloproteinases and tissue inhibitor of metalloproteinase-2 in idiopathic hemotympanum and otitis media with effusion

    PubMed Central

    Moon, Sung K.; Linthicum, Fred H.; Yang, Hae Dong; Lee, Seung Joo; Park, Keehyun

    2008-01-01

    Conclusion The expression profile of matrix metalloproteinases (MMP) and tissue inhibitor of metalloproteinase-2 (TIMP-2) was specific to the type of middle ear effusion. Further studies are necessary for elucidating its correlation with the sequelae of otitis media with effusion (OME) and idiopathic hemotympanum. Objectives We aimed to investigate the relative activities of gelatinases (MMP-2 and 9), stromelysin-1 (MMP-3), matrilysin-1 (MMP-7) as well as measuring TIMP-2 levels in the serous and mucous effusions of OME and hemorrhagic effusion of the idiopathic hemotympanum. Method Middle ear effusions were collected from patients with OME and idiopathic hemotympanum, and were classified as mucoid, serous or hemorrhagic. MMP activity in the effusion samples was examined by gelatin and casein zymography. Levels of TIMP-2 were measured by ELISA. Human temporal bones sections, with and without otitis media (OM), were examined histologically. Results One case showed tympanic membrane thinning in the OM group, but none in the control group. While MMP-2 was present in all effusions, the active form of MMP-2 was found only in mucous effusions. MMP-3 and MMP-7 activity was detected only in the mucous effusions. MMP-9 exhibited activity in all effusions, with the highest levels in mucous effusions. TIMP-2 levels were markedly elevated in serous effusions. PMID:17851959

  18. Growth-inhibiting extracellular matrix proteins also inhibit electrical activity by reducing calcium and increasing potassium conductances.

    PubMed

    Vargas, J; De-Miguel, F F

    2009-01-23

    Inhibitionof neurite sprouting and electrical activity by extracellular matrix (ECM) glycoproteins was studied during neurite regeneration by using anterior pagoda (AP) neurons of the leech. Adult isolated neurons were plated in culture inside ganglion capsules, which among many ECM proteins, contain a group of inhibitory peanut lectin- (PNA) binding glycoproteins. These proteins inhibit neurite production and contribute to the formation of a bipolar outgrowth pattern by AP neurons. Addition of PNA lectin to the culture medium to block the inhibitory effects of ECM glycoproteins induced an increase of neurite sprouting, the loss of the bipolar pattern, and also an increase in the amplitude and duration of action potentials evoked by intracellular current injection. PNA lectin had independent effects on neurite sprouting and electrical activity, since there was no correlation between the total neurite length and the amplitude of the action potentials. Moreover, action potentials were increased by the presence of PNA lectin even in neurons that did not grow. The changes induced by PNA lectin on the active conductances underlying the action potentials were estimated by quantitative model simulations. We predict that the increases in the amplitude and duration of the action potential induced by PNA lectin were due to an increase in a calcium conductance and a reduction in the delayed rectifier potassium conductance. Our results suggest that inhibitory ECM glycoproteins may use independent signaling pathways to inhibit neurite sprouting and electrical activity. These proteins affect the action potential by changing the proportion of inward and outward active conductances. PMID:18976697

  19. Interfacial Engineering of Bimetallic Ag/Pt Nanoparticles on Reduced Graphene Oxide Matrix for Enhanced Antimicrobial Activity.

    PubMed

    Zhang, Mei; Zhao, Yanhua; Yan, Li; Peltier, Raoul; Hui, Wenli; Yao, Xi; Cui, Yali; Chen, Xianfeng; Sun, Hongyan; Wang, Zuankai

    2016-04-01

    Environmental biofouling caused by the formation of biofilm has been one of the most urgent global concerns. Silver nanoparticles (NPs), owing to their wide-spectrum antimicrobial property, have been widely explored to combat biofilm, but their extensive use has raised growing concern because they persist in the environment. Here we report a novel hybrid nanocomposite that imparts enhanced antimicrobial activity and low cytotoxicity yet with the advantage of reduced silver loading. The nanocomposite consists of Pt/Ag bimetallic NPs (BNPs) decorated on the porous reduced graphene oxide (rGO) nanosheets. We demonstrate that the enhanced antimicrobial property against Escherichia coli is ascribed to the intricate control of the interfaces between metal compositions, rGO matrix, and bacteria, where the BNPs lead to a rapid release of silver ions, and the trapping of bacteria by the porous rGO matrix further provides high concentration silver ion sites for efficient bacteria-bactericide interaction. We envision that our facile approach significantly expands the design space for the creation of silver-based antimicrobial materials to achieve a wide spectrum of functionalities. PMID:27007980

  20. Regulation of Matrix Metalloproteinase-2 Activity by COX-2-PGE2-pAKT Axis Promotes Angiogenesis in Endometriosis

    PubMed Central

    Ray, Amlan K.; DasMahapatra, Pramathes; Swarnakar, Snehasikta

    2016-01-01

    Endometriosis is characterized by the ectopic development of the endometrium which relies on angiogenesis. Although studies have identified the involvement of different matrix metalloproteinases (MMPs) in endometriosis, no study has yet investigated the role of MMP-2 in endometriosis-associated angiogenesis. The present study aims to understand the regulation of MMP-2 activity in endothelial cells and on angiogenesis during progression of ovarian endometriosis. Histological and biochemical data showed increased expressions of vascular endothelial growth factor (VEGF), VEGF receptor-2, cycloxygenase (COX)-2, von Willebrand factor along with angiogenesis during endometriosis progression. Women with endometriosis showed decreased MMP-2 activity in eutopic endometrium as compared to women without endometriosis. However, ectopic ovarian endometrioma showed significantly elevated MMP-2 activity with disease severity. In addition, increased MT1MMP and decreased tissue inhibitors of metalloproteinases (TIMP)-2 expressions were found in the late stages of endometriosis indicating more MMP-2 activation with disease progression. In vitro study using human endothelial cells showed that prostaglandin E2 (PGE2) significantly increased MMP-2 activity as well as tube formation. Inhibition of COX-2 and/or phosphorylated AKT suppressed MMP-2 activity and endothelial tube formation suggesting involvement of PGE2 in regulation of MMP-2 activity during angiogenesis. Moreover, specific inhibition of MMP-2 by chemical inhibitor significantly reduced cellular migration, invasion and tube formation. In ovo assay showed decreased angiogenic branching upon MMP-2 inhibition. Furthermore, a significant reduction of lesion numbers was observed upon inhibition of MMP-2 and COX-2 in mouse model of endometriosis. In conclusion, our study establishes the involvement of MMP-2 activity via COX-2-PGE2-pAKT axis in promoting angiogenesis during endometriosis progression. PMID:27695098

  1. Conformable, flexible, large-area networks of pressure and thermal sensors with organic transistor active matrixes

    NASA Astrophysics Data System (ADS)

    Someya, Takao; Kato, Yusaku; Sekitani, Tsuyoshi; Iba, Shingo; Noguchi, Yoshiaki; Murase, Yousuke; Kawaguchi, Hiroshi; Sakurai, Takayasu

    2005-08-01

    Skin-like sensitivity, or the capability to recognize tactile information, will be an essential feature of future generations of robots, enabling them to operate in unstructured environments. Recently developed large-area pressure sensors made with organic transistors have been proposed for electronic artificial skin (E-skin) applications. These sensors are bendable down to a 2-mm radius, a size that is sufficiently small for the fabrication of human-sized robot fingers. Natural human skin, however, is far more complex than the transistor-based imitations demonstrated so far. It performs other functions, including thermal sensing. Furthermore, without conformability, the application of E-skin on three-dimensional surfaces is impossible. In this work, we have successfully developed conformable, flexible, large-area networks of thermal and pressure sensors based on an organic semiconductor. A plastic film with organic transistor-based electronic circuits is processed to form a net-shaped structure, which allows the E-skin films to be extended by 25%. The net-shaped pressure sensor matrix was attached to the surface of an egg, and pressure images were successfully obtained in this configuration. Then, a similar network of thermal sensors was developed with organic semiconductors. Next, the possible implementation of both pressure and thermal sensors on the surfaces is presented, and, by means of laminated sensor networks, the distributions of pressure and temperature are simultaneously obtained. Author contributions: T. Someya designed research; T. Someya, Y.K., T. Sekitani, S.I., Y.N., Y.M., H.K., and T. Sakurai performed research; and T. Someya wrote the paper.This paper was submitted directly (Track II) to the PNAS office.Freely available online through the PNAS open access option.Abbreviations: E-skin, electronic artificial skin; IDS, source-drain current; PTCDI, 3,4,9,10-perylene-tetracarboxylic-diimide; parylene, polychloro-para-xylylene; CuPc, copper

  2. Spatial clustering of pixels of a multispectral image

    SciTech Connect

    Conger, James Lynn

    2014-08-19

    A method and system for clustering the pixels of a multispectral image is provided. A clustering system computes a maximum spectral similarity score for each pixel that indicates the similarity between that pixel and the most similar neighboring. To determine the maximum similarity score for a pixel, the clustering system generates a similarity score between that pixel and each of its neighboring pixels and then selects the similarity score that represents the highest similarity as the maximum similarity score. The clustering system may apply a filtering criterion based on the maximum similarity score so that pixels with similarity scores below a minimum threshold are not clustered. The clustering system changes the current pixel values of the pixels in a cluster based on an averaging of the original pixel values of the pixels in the cluster.

  3. Progesterone-induced blocking factor differentially regulates trophoblast and tumor invasion by altering matrix metalloproteinase activity.

    PubMed

    Halasz, Melinda; Polgar, Beata; Berta, Gergely; Czimbalek, Livia; Szekeres-Bartho, Julia

    2013-12-01

    Invasiveness is a common feature of trophoblast and tumors; however, while tumor invasion is uncontrolled, trophoblast invasion is strictly regulated. Both trophoblast and tumor cells express high levels of the immunomodulatory progesterone-induced blocking factor (PIBF), therefore, we aimed to test the possibility that PIBF might be involved in invasion. To this aim, we used PIBF-silenced or PIBF-treated trophoblast (HTR8/Svneo, and primary trophoblast) and tumor (HT-1080, A549, HCT116, PC3) cell lines. Silencing of PIBF increased invasiveness as well as MMP-2,-9 secretion of HTR8/SVneo, and decreased those of HT-1080 cells. PIBF induced immediate STAT6 activation in both cell lines. Silencing of IL-4Rα abrogated all the above effects of PIBF, suggesting that invasion-related signaling by PIBF is initiated through the IL-4Rα/PIBF-receptor complex. In HTR-8/SVneo, PIBF induced fast, but transient Akt and ERK phosphorylation, whereas in tumor cells, PIBF triggered sustained Akt, ERK, and late STAT3 activation. The late signaling events might be due to indirect action of PIBF. PIBF induced the expression of EGF and HB-EGF in HT-1080 cells. The STAT3-activating effect of PIBF was reduced in HB-EGF-deficient HT-1080 cells, suggesting that PIBF-induced HB-EGF contributes to late STAT3 activation. PIBF binds to the promoters of IL-6, EGF, and HB-EGF; however, the protein profile of the protein/DNA complex is different in the two cell lines. We conclude that in tumor cells, PIBF induces proteins, which activate invasion signaling, while-based on our previous data-PIBF might control trophoblast invasion by suppressing proinvasive genes.

  4. α-Solanine inhibits human melanoma cell migration and invasion by reducing matrix metalloproteinase-2/9 activities.

    PubMed

    Lu, Ming-Kun; Shih, Yuan-Wei; Chang Chien, Tzu-Tsung; Fang, Li-Heng; Huang, Hsiang-Ching; Chen, Pin-Shern

    2010-01-01

    α-Solanine, a naturally occurring steroidal glycoalkaloid in potato sprouts, was found to possess anti-carcinogenic properties, such as inhibiting proliferation and inducing apoptosis of tumor cells. However, the effect of α-solanine on cancer metastasis remains unclear. In the present study, we examined the effect of α-solanine on metastasis in vitro. Data demonstrated that α-solanine inhibited proliferation of human melanoma cell line A2058 in a dose-dependent manner. When treated with non-toxic doses of α-solanine, cell migration and invasion were markedly suppressed. Furthermore, α-solanine reduced the activity of matrix metalloproteinase-2 (MMP-2) and MMP-9, which are involved in the migration and invasion of cancer cells. Our biochemical assays indicated that α-solanine potently suppressed the phosphorylation of c-Jun N-terminal kinase (JNK), phosphatidylinositide-3 kinase (PI3K) and Akt, while it did not affect phosphorylation of extracellular signal regulating kinase (ERK). In addition, α-solanine significantly decreased the nuclear level of nuclear factor kappa B (NF-κB), suggesting that α-solanine inhibited NF-κB activity. Taken together, the results suggested that α-solanine inhibited migration and invasion of A2058 cells by reducing MMP-2/9 activities. It also inhibited JNK and PI3K/Akt signaling pathways as well as NF-κB activity. These findings reveal new therapeutic potential for α-solanine in anti-metastatic therapy.

  5. Performance evaluation of nonnegative matrix factorization algorithms to estimate task-related neuronal activities from fMRI data.

    PubMed

    Ding, Xiaoyu; Lee, Jong-Hwan; Lee, Seong-Whan

    2013-04-01

    Nonnegative matrix factorization (NMF) is a blind source separation (BSS) algorithm which is based on the distinct constraint of nonnegativity of the estimated parameters as well as on the measured data. In this study, according to the potential feasibility of NMF for fMRI data, the four most popular NMF algorithms, corresponding to the following two types of (1) least-squares based update [i.e., alternating least-squares NMF (ALSNMF) and projected gradient descent NMF] and (2) multiplicative update (i.e., NMF based on Euclidean distance and NMF based on divergence cost function), were investigated by using them to estimate task-related neuronal activities. These algorithms were applied firstly to individual data from a single subject and, subsequently, to group data sets from multiple subjects. On the single-subject level, although all four algorithms detected task-related activation from simulated data, the performance of multiplicative update NMFs was significantly deteriorated when evaluated using visuomotor task fMRI data, for which they failed in estimating any task-related neuronal activities. In group-level analysis on both simulated data and real fMRI data, ALSNMF outperformed the other three algorithms. The presented findings may suggest that ALSNMF appears to be the most promising option among the tested NMF algorithms to extract task-related neuronal activities from fMRI data.

  6. Large-Scale Variational Two-Electron Reduced-Density-Matrix-Driven Complete Active Space Self-Consistent Field Methods.

    PubMed

    Fosso-Tande, Jacob; Nguyen, Truong-Son; Gidofalvi, Gergely; DePrince, A Eugene

    2016-05-10

    A large-scale implementation of the complete active space self-consistent field (CASSCF) method is presented. The active space is described using the variational two-electron reduced-density-matrix (v2RDM) approach, and the algorithm is applicable to much larger active spaces than can be treated using configuration-interaction-driven methods. Density fitting or Cholesky decomposition approximations to the electron repulsion integral tensor allow for the simultaneous optimization of large numbers of external orbitals. We have tested the implementation by evaluating singlet-triplet energy gaps in the linear polyacene series and two dinitrene biradical compounds. For the acene series, we report computations that involve active spaces consisting of as many as 50 electrons in 50 orbitals and the simultaneous optimization of 1892 orbitals. For the dinitrene compounds, we find that the singlet-triplet gaps obtained from v2RDM-driven CASSCF with partial three-electron N-representability conditions agree with those obtained from configuration-interaction-driven approaches to within one-third of 1 kcal mol(-1). When enforcing only the two-electron N-representability conditions, v2RDM-driven CASSCF yields less accurate singlet-triplet energy gaps in these systems, but the quality of the results is still far superior to those obtained from standard single-reference approaches. PMID:27065086

  7. Estimating neighborhood variability with a binary comparison matrix.

    USGS Publications Warehouse

    Murphy, D.L.

    1985-01-01

    A technique which utilizes a binary comparison matrix has been developed to implement a neighborhood function for a raster format data base. The technique assigns an index value to the center pixel of 3- by 3-pixel neighborhoods. The binary comparison matrix provides additional information not found in two other neighborhood variability statistics; the function is sensitive to both the number of classes within the neighborhood and the frequency of pixel occurrence in each of the classes. Application of the function to a spatial data base from the Kenai National Wildlife Refuge, Alaska, demonstrates 1) the numerical distribution of the index values, and 2) the spatial patterns exhibited by the numerical values. -Author

  8. DETECTORS AND EXPERIMENTAL METHODS: Study of the characteristics of a scintillation array and single pixels for nuclear medicine imaging applications

    NASA Astrophysics Data System (ADS)

    Zhu, Jie; Ma, Hong-Guang; Ma, Wen-Yan; Zeng, Hui; Wang, Zhao-Min; Xu, Zi-Zong

    2009-04-01

    By using a pixelized Nal(Tl) crystal array coupled to a R2486 PSPMT, the characteristics of the array and of a single pixel, such as the light output, energy resolution, peak-to-valley ratio (P/V) and imaging performance of the detector were studied. The pixel size of the NaI(TI) scintillation pixel array is 2 mm×2 mm×5 mm. There are in total 484 pixels in a 22 × 22 matrix. In the pixel spectrum an average peak-to-valley ratio (P/V) of 16 was obtained. In the image of all the pixels, good values for the Peak-to-Valley ratios could be achieved, namely a mean of 17, a maximum of 45 and the average peak FWHM (the average value of intrinsic spatial resolution) of 2.3 mm. However, the PSPMT non-uniform response and the scintillation pixels array inhomogeneities degrade the imaging performance of the detector.

  9. Increased expression and activation of gelatinolytic matrix metalloproteinases is associated with the progression and recurrence of human cervical cancer.

    PubMed

    Sheu, Bor-Ching; Lien, Huang-Chun; Ho, Hong-Nerng; Lin, Ho-Hsiung; Chow, Song-Nan; Huang, Su-Cheng; Hsu, Su-Ming

    2003-10-01

    Cancer-derived matrix metalloproteinases (MMPs) are proposed to be essential for tumor stromal invasion and subsequent metastasis. To explore the role of MMPs in cancer progression, we examined the expression of various MMPs and tissue inhibitors of MMPs in precancerous and cancerous lesions of the uterine cervix. Immunohistochemical studies demonstrated that MMP-2 and MMP-9 were expressed in >90% of squamous cell carcinomas (SCC) and 83-100% of high-grade squamous intraepithelial lesions (HSIL), but were less frequently expressed in low-grade squamous intraepithelial lesions and normal squamous epithelium (13%). MMP-1, MMP-14, and MMP-15 were detected in 55-81% of SCC cases, and MMP-1 was detected in 39% of HSIL. The tissue inhibitors of MMPs were weakly expressed in SCC (10-61%). By direct analysis of enzyme activities in microdissected specimens, we found that the gelatinolytic activity of MMP-9 was significantly higher in HSIL and SCC than in normal cervix (P < 0.01). The levels of active-form MMP-2 increased progressively from HSIL to SCC of stage I and more advanced stages (P < 0.01). The gelatinolytic activity of MMP-9 and active-form MMP-2 in SCC were strongly correlated with lymphovascular permeation and subsequent lymph node metastasis (P < 0.02). Moreover, the gelatinolytic activity and immunoreactive percentage of both MMP-2 and MMP-9 were significantly higher in SCC cases who had a recurrence than in those who remained free of disease (P < 0.001). Thus, our data demonstrate progressively up-regulated expression of MMP-2 and MMP-9 with SCC progression, and significant associations among their gelatinolytic activity and stage, nodal metastasis, and recurrence.

  10. Electret film-enhanced triboelectric nanogenerator matrix for self-powered instantaneous tactile imaging.

    PubMed

    Yang, Ya; Zhang, Hulin; Zhong, Xiandai; Yi, Fang; Yu, Ruomeng; Zhang, Yue; Wang, Zhong Lin

    2014-03-12

    We report the first self-powered electronic skin that consists of light-emitting diode (LED) and triboelectric nanogenerator (TENG) arrays that can be utilized for spatially mapping applied instantaneous-touch events and tracking the movement location of the target object by recording the electroluminescent signals of the LEDs without external power sources. The electret film-based TENG can deliver an open-circuit voltage of about -1070 V, a short-circuit current density of 10 mA/m(2), and a power density of 288 mW/m(2) on an external load of 100 MΩ. The LEDs can be turned on locally when the back surface of the active matrix is touched, and the intensity of the emitted light depends on the magnitude of the applied local pressure on the device. A constructed active matrix of the LED-TENG array (8 × 7 pixels) can achieve self-powered, visual, and high-resolution tactile sensing by recording the electroluminescent signals from all of the pixels, where the active size of each pixel can be decreased to 10 mm(2). This work is a significant step forward in self-powered tactile-mapping visualization technology, with a wide range of potential applications in touchpad technology, personal signatures, smart wallpapers, robotics, and safety-monitoring devices.

  11. A signal processing approach for enhanced Acoustic Emission data analysis in high activity systems: Application to organic matrix composites

    NASA Astrophysics Data System (ADS)

    Kharrat, M.; Ramasso, E.; Placet, V.; Boubakar, M. L.

    2016-03-01

    Structural elements made of Organic Matrix Composites (OMC) under complex loading may suffer from high Acoustic Emission (AE) activity caused by the emergence of different emission sources at high rates with high noise level, which finally engender continuous emissions. The detection of hits in this situation becomes a challenge particularly during fatigue tests. This work suggests an approach based on the Discrete Wavelet Transform (DWT) denoising applied on signal segments. A particular attention is paid to the adjustment of the denoising parameters based on pencil lead breaks and their influence on the quality of the denoised AE signals. The validation of the proposed approach is performed on a ring-shaped Carbon Fiber Reinforced Plastics (CFRP) under in-service-like conditions involving continuous emissions with superimposed damage-related transients. It is demonstrated that errors in hit detection are greatly reduced leading to a better identification of the natural damage scenario based on AE signals.

  12. Sequestration of nanoparticles by an EPS matrix reduces the particle-specific bactericidal activity

    PubMed Central

    Wang, Qian; Kang, Fuxing; Gao, Yanzheng; Mao, Xuewei; Hu, Xiaojie

    2016-01-01

    Most artificial nanomaterials are known to exhibit broad-spectrum bactericidal activity; however, the defence mechanisms that bacteria use based on extracellular polymeric substances (EPS) to detoxify nanoparticles (NPs) are not well known. We ruled out the possibility of ion-specific bactericidal activity by showing the lack of equivalent dissolved zinc and silicon toxicity and determined the particle-specific toxicity of ZnO and SiO2 nanoparticles (ZnONPs/SiO2NPs) through dialysis isolation experiments. Surprisingly, the manipulation of the E. coli EPS (i.e., no EPS manipulation or EPS removal by sonication/centrifugation) showed that their particle-specific bactericidal activity could be antagonized by NP-EPS sequestration. The survival rates of pristine E. coli (no EPS manipulation) reached 65% (ZnONPs, 500 mg L−1) and 79% (SiO2NPs, 500 mg L−1), whereas survival rates following EPS removal by sonication/centrifugation were 11% and 63%, respectively. Transmission electron microscopy (TEM) combined with fluorescence micro-titration analysis and Fourier-transform infrared spectroscopy (FTIR) showed that protein-like substances (N-H and C-N in amide II) and secondary carbonyl groups (C=O) in the carboxylic acids of EPS acted as important binding sites that were involved in NP sequestration. Accordingly, the amount and composition of EPS produced by bacteria have important implications for the bactericidal efficacy and potential environmental effects of NPs. PMID:26856606

  13. Activation and localization of matrix metalloproteinase-2 and -9 in the skeletal muscle of the muscular dystrophy dog (CXMDJ)

    PubMed Central

    Fukushima, Kazuhiro; Nakamura, Akinori; Ueda, Hideho; Yuasa, Katsutoshi; Yoshida, Kunihiro; Takeda, Shin'ichi; Ikeda, Shu-ichi

    2007-01-01

    Background Matrix metalloproteinases (MMPs) are key regulatory molecules in the formation, remodeling and degradation of all extracellular matrix (ECM) components in both physiological and pathological processes in various tissues. The aim of this study was to examine the involvement of gelatinase MMP family members, MMP-2 and MMP-9, in dystrophin-deficient skeletal muscle. Towards this aim, we made use of the canine X-linked muscular dystrophy in Japan (CXMDJ) model, a suitable animal model for Duchenne muscular dystrophy. Methods We used surgically biopsied tibialis cranialis muscles of normal male dogs (n = 3) and CXMDJ dogs (n = 3) at 4, 5 and 6 months of age. Muscle sections were analyzed by conventional morphological methods and in situ zymography to identify the localization of MMP-2 and MMP-9. MMP-2 and MMP-9 activity was examined by gelatin zymography and the levels of the respective mRNAs in addition to those of regulatory molecules, including MT1-MMP, TIMP-1, TIMP-2, and RECK, were analyzed by semi-quantitative RT-PCR. Results In CXMDJ skeletal muscle, multiple foci of both degenerating and regenerating muscle fibers were associated with gelatinolytic MMP activity derived from MMP-2 and/or MMP-9. In CXMDJ muscle, MMP-9 immunoreactivity localized to degenerated fibers with inflammatory cells. Weak and disconnected immunoreactivity of basal lamina components was seen in MMP-9-immunoreactive necrotic fibers of CXMDJ muscle. Gelatinolytic MMP activity observed in the endomysium of groups of regenerating fibers in CXMDJ did not co-localize with MMP-9 immunoreactivity, suggesting that it was due to the presence of MMP-2. We observed increased activities of pro MMP-2, MMP-2 and pro MMP-9, and levels of the mRNAs encoding MMP-2, MMP-9 and the regulatory molecules, MT1-MMP, TIMP-1, TIMP-2, and RECK in the skeletal muscle of CXMDJ dogs compared to the levels observed in normal controls. Conclusion MMP-2 and MMP-9 are likely involved in the pathology of dystrophin

  14. Measurement results of DIPIX pixel sensor developed in SOI technology

    NASA Astrophysics Data System (ADS)

    Ahmed, Mohammed Imran; Arai, Yasuo; Idzik, Marek; Kapusta, Piotr; Miyoshi, Toshinobu; Turala, Michal

    2013-08-01

    The development of integration type pixel detectors presents interest for physics communities because it brings optimization of design, simplicity of production-which means smaller cost, and reduction of detector material budget. During the last decade a lot of research and development activities took place in the field of CMOS Silicon-On-Insulator (SOI) technology resulting in improvement in wafer size, wafer resistivity and MIM capacitance. Several ideas have been tested successfully and are gradually entering into the application phase. Some of the novel concepts exploring SOI technology are pursued at KEK; several prototypes of dual mode integration type pixel (DIPIX) have been recently produced and described. This report presents initial test results of some of the prototypes including tests obtained with the infrared laser beams and Americium (Am-241) source. The Equivalent Noise Charge (ENC) of 86 e - has been measured. The measured performance demonstrates that SOI technology is a feasible choice for future applications.

  15. Development of thin edgeless silicon pixel sensors on epitaxial wafers

    NASA Astrophysics Data System (ADS)

    Boscardin, M.; Bosisio, L.; Contin, G.; Giacomini, G.; Manzari, V.; Orzan, G.; Rashevskaya, I.; Ronchin, S.; Zorzi, N.

    2014-09-01

    The paper reports on the development of novel p-on-n thin edgeless planar pixel sensors, compatible with ALICE front-end electronics, fabricated by FBK on epitaxial material. The focus of the activity is the minimization of the material budget required for hybrid pixel detectors. This goal has been addressed in two different stages. In the first one, planar pixel detectors fabricated on epitaxial wafers have been thinned and bonded to the readout chips. The second stage is described by the present paper: the `active edge' concept has been studied for the reduction of the dead area at the periphery of the devices. An overview of the key technological steps and of the electrical characterization of the fabricated sensors is given. In addition, the preliminary results on the static behavior of test sensors after neutron irradiation at different fluences (up to 2.5 × 1015 1 MeV-neq/cm2) are reported. The results demonstrate that these kinds of devices are a viable solution for the reduction of the material budget while maintaining the typical electrical characteristics expected from radiation silicon sensors.

  16. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Seshadri, S.; Cole, D. M.; Hancock, B. R.; Smith, R. M.

    2008-01-01

    Electronic coupling effects such as Inter-Pixel Capacitance (IPC) affect the quantitative interpretation of image data from CMOS, hybrid visible and infrared imagers alike. Existing methods of characterizing IPC do not provide a map of the spatial variation of IPC over all pixels. We demonstrate a deterministic method that provides a direct quantitative map of the crosstalk across an imager. The approach requires only the ability to reset single pixels to an arbitrary voltage, different from the rest of the imager. No illumination source is required. Mapping IPC independently for each pixel is also made practical by the greater S/N ratio achievable for an electrical stimulus than for an optical stimulus, which is subject to both Poisson statistics and diffusion effects of photo-generated charge. The data we present illustrates a more complex picture of IPC in Teledyne HgCdTe and HyViSi focal plane arrays than is presently understood, including the presence of a newly discovered, long range IPC in the HyViSi FPA that extends tens of pixels in distance, likely stemming from extended field effects in the fully depleted substrate. The sensitivity of the measurement approach has been shown to be good enough to distinguish spatial structure in IPC of the order of 0.1%.

  17. Porous poly(DL-lactic acid) matrix film with antimicrobial activities for wound dressing application.

    PubMed

    Chitrattha, Sasiprapa; Phaechamud, Thawatchai

    2016-01-01

    Poly(lactic acid) (PLA) is polymeric biomaterial that has been used for wound dressing due to its biodegradability and biocompatibility. However, PLA has some limitations including poor toughness, low degradation rate and high hydrophobicity. The aim of this study is to develop an antibiotic drug-loaded PLA porous film as wound dressing with antibacterial activity. PLA porous film was fabricated by temperature change technique using solvent casting method. Polyethylene glycol (PEG) 400 was added for improving the pore interconnectivity of film. Gentamicin sulfate (GS) or metronidazole (MZ) was incorporated into PLA porous films. PLA containing PEG 400 exhibited the more amorphous form than plain PLA film and contained 55.31 ± 2.85% porosity and 20 μm of the pore size which significantly improved the water vapor transmission rate, oxygen transmission rate, degradation rate and percentage of drug release, respectively. Drug-loaded porous films efficiently inhibited the bacteria growth. GS-loaded film inhibited Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa, whereas MZ-loaded film inhibited Bacteroides fragilis and the sustainable antibacterial activity was attained for 7 days.

  18. Generation of biologically active endostatin fragments from human collagen XVIII by distinct matrix metalloproteases

    SciTech Connect

    Heljasvaara, Ritva; Nyberg, Pia; Luostarinen, Jani; Parikka, Mataleena; Heikkilae, Pia; Rehn, Marko; Sorsa, Timo; Salo, Tuula; Pihlajaniemi, Taina . E-mail: taina.pihlajaniemi@oulu.fi

    2005-07-15

    Endostatin, a potent inhibitor of endothelial cell proliferation, migration, angiogenesis and tumor growth, is proteolytically cleaved from the C-terminal noncollagenous NC1 domain of type XVIII collagen. We investigated the endostatin formation from human collagen XVIII by several MMPs in vitro. The generation of endostatin fragments differing in molecular size (24-30 kDa) and in N-terminal sequences was identified in the cases of MMP-3, -7, -9, -13 and -20. The cleavage sites were located in the protease-sensitive hinge region between the trimerization and endostatin domains of NC1. MMP-1, -2, -8 and -12 did not show any significant activity against the C-terminus of collagen XVIII. The anti-proliferative effect of the 20-kDa endostatin, three longer endostatin-containing fragments generated in vitro by distinct MMPs and the entire NC1 domain, on bFGF-stimulated human umbilical vein endothelial cells was established. The anti-migratory potential of some of these fragments was also studied. In addition, production of endostatin fragments between 24-30 kDa by human hepatoblastoma cells was shown to be due to MMP action on type XVIII collagen. Our results indicate that certain, especially cancer-related, MMP family members can generate biologically active endostatin-containing polypeptides from collagen XVIII and thus, by releasing endostatin fragments, may participate in the inhibition of endothelial cell proliferation, migration and angiogenesis.

  19. Porous poly(DL-lactic acid) matrix film with antimicrobial activities for wound dressing application.

    PubMed

    Chitrattha, Sasiprapa; Phaechamud, Thawatchai

    2016-01-01

    Poly(lactic acid) (PLA) is polymeric biomaterial that has been used for wound dressing due to its biodegradability and biocompatibility. However, PLA has some limitations including poor toughness, low degradation rate and high hydrophobicity. The aim of this study is to develop an antibiotic drug-loaded PLA porous film as wound dressing with antibacterial activity. PLA porous film was fabricated by temperature change technique using solvent casting method. Polyethylene glycol (PEG) 400 was added for improving the pore interconnectivity of film. Gentamicin sulfate (GS) or metronidazole (MZ) was incorporated into PLA porous films. PLA containing PEG 400 exhibited the more amorphous form than plain PLA film and contained 55.31 ± 2.85% porosity and 20 μm of the pore size which significantly improved the water vapor transmission rate, oxygen transmission rate, degradation rate and percentage of drug release, respectively. Drug-loaded porous films efficiently inhibited the bacteria growth. GS-loaded film inhibited Staphylococcus aureus, Proteus mirabilis, Pseudomonas aeruginosa, whereas MZ-loaded film inhibited Bacteroides fragilis and the sustainable antibacterial activity was attained for 7 days. PMID:26478412

  20. Pixels, Blocks of Pixels, and Polygons: Choosing a Spatial Unit for Thematic Accuracy Assessment

    EPA Science Inventory

    Pixels, polygons, and blocks of pixels are all potentially viable spatial assessment units for conducting an accuracy assessment. We develop a statistical population-based framework to examine how the spatial unit chosen affects the outcome of an accuracy assessment. The populati...

  1. Uncooled infrared detectors toward smaller pixel pitch with newly proposed pixel structure

    NASA Astrophysics Data System (ADS)

    Tohyama, Shigeru; Sasaki, Tokuhito; Endoh, Tsutomu; Sano, Masahiko; Katoh, Kouji; Kurashina, Seiji; Miyoshi, Masaru; Yamazaki, Takao; Ueno, Munetaka; Katayama, Haruyoshi; Imai, Tadashi

    2011-06-01

    Since authors have successfully demonstrated uncooled infrared (IR) focal plane array (FPA) with 23.5 um pixel pitch, it has been widely utilized for commercial applications such as thermography, security camera and so on. One of the key issues for uncooled IR detector technology is to shrink the pixel size. The smaller the pixel pitch, the more the IR camera products become compact and the less cost. This paper proposes a new pixel structure with a diaphragm and beams which are placed in different level, to realize an uncooled IRFPA with smaller pixel pitch )<=17 μm). The upper level consists of diaphragm with VOx bolometer and IR absorber layers, while the lower level consists of the two beams, which are designed to place on the adjacent pixels. The test devices of this pixel design with 12 um, 15 um and 17 um pitch have been fabricated on the Si ROIC of QVGA (320 × 240) with 23.5 um pitch. Their performances reveal nearly equal to the IRFPA with 23.5 um pitch. For example, noise equivalent temperature difference (NETD) of 12 μm pixel is 63.1 mK with thermal time constant of 14.5 msec. In addition, this new structure is expected to be more effective for the existing IRFPA with 23.5 um pitch in order to improve the IR responsivity.

  2. Melatonin inhibits TPA-induced oral cancer cell migration by suppressing matrix metalloproteinase-9 activation through the histone acetylation

    PubMed Central

    Yeh, Chia-Ming; Lin, Chiao-Wen; Yang, Jia-Sin; Yang, Wei-En; Su, Shih-Chi; Yang, Shun-Fa

    2016-01-01

    Melatonin exerts antimetastatic effects on liver and breast cancer and also inhibits matrix metalloproteinase (MMP) activity. However, the detailed impacts and underlying mechanisms of melatonin on oral cancer cell metastasis are still unclear. This study showed that melatonin attenuated the 12-O-tetradecanoylphorbol-13-acetate-induced migration of oral cancer cell lines, HSC-3 and OECM-1. Zymography, quantitative real-time PCR, and Western blotting analyses revealed that melatonin lessened MMP-9 enzyme activity as well as the expression of MMP-9 mRNA and protein. Furthermore, melatonin suppressed the phosphorylation of the ERK1/2 signalling pathway, which dampened MMP-9 gene transcription by affecting the expression of transcriptional coactivators, such as CREB-binding protein (CREBBP) and E1A binding protein p300 (EP300), and decreasing histone acetylation in HSC-3 and OECM-1 cells. Examinations on clinical samples exhibited that MMP-9, CREBBP, and EP300 were significantly increased in oral cancer tissues. Moreover, the relative level of CREBBP was positively correlated with the expression of MMP-9 and EP300. In conclusion, we demonstrated that melatonin inhibits the motility of HSC-3 and OECM-1 cells in vitro through a molecular mechanism that involves attenuation of MMP-9 expression and activity mediated by decreased histone acetylation. PMID:26980735

  3. Optimal level activity of matrix metalloproteinases is critical for adult visual plasticity in the healthy and stroke-affected brain

    PubMed Central

    Pielecka-Fortuna, Justyna; Kalogeraki, Evgenia; Fortuna, Michal G; Löwel, Siegrid

    2015-01-01

    The ability of the adult brain to undergo plastic changes is of particular interest in medicine, especially regarding recovery from injuries or improving learning and cognition. Matrix metalloproteinases (MMPs) have been associated with juvenile experience-dependent primary visual cortex (V1) plasticity, yet little is known about their role in this process in the adult V1. Activation of MMPs is a crucial step facilitating structural changes in a healthy brain; however, upon brain injury, upregulated MMPs promote the spread of a lesion and impair recovery. To clarify these seemingly opposing outcomes of MMP-activation, we examined the effects of MMP-inhibition on experience-induced plasticity in healthy and stoke-affected adult mice. In healthy animals, 7-day application of MMP-inhibitor prevented visual plasticity. Additionally, treatment with MMP-inhibitor once but not twice following stroke rescued plasticity, normally lost under these conditions. Our data imply that an optimal level of MMP-activity is crucial for adult visual plasticity to occur. DOI: http://dx.doi.org/10.7554/eLife.11290.001 PMID:26609811

  4. Anti-photoaging activity and inhibition of matrix metalloproteinase (MMP) by marine red alga, Corallina pilulifera methanol extract

    NASA Astrophysics Data System (ADS)

    Ryu, BoMi; Qian, Zhong-Ji; Kim, Moon-Moo; Nam, Ki Wan; Kim, Se-Kwon

    2009-02-01

    Matrix metalloproteinases (MMPs), a key component in photoaging of the skin due to exposure to ultraviolet A, appear to be increased by UV-irradiation-associated generation of reactive oxygen species (ROS). In this study, the alga Corallina pilulifera methanol (CPM) extract has been shown to exert a potent antioxidant activity and protective effect on UVA-induced oxidative stress of human dermal fibroblast (HDF) cell. Antioxidant evaluated by various antioxidant assays. These include reducing power, total antioxidant, DPPH radical scavenging, hydroxyl radical scavenging and protective effect on DNA damage caused by hydroxyl radicals generated. Further, the ROS level was detected using a fluorescence probe, 2',7'-dichlorofluorescein diacetate (DCFH-DA), which could be converted to highly fluorescent dichlorofluorescein (DCF) with the presence of intracellular ROS on HT-1080 cells. Those various antioxidant activities were compared to standard antioxidants such as α-tocopherol. In addition, the in vitro activities of MMP-2 and MMP-9 in HDF cell were inhibited by C. pilulifera methanol extract dose dependently by using gelatin zymography method. The results obtained in the present study suggested that the C. pilulifera methanol extract may be a potential source of natural anti-photoaging.

  5. Melatonin inhibits TPA-induced oral cancer cell migration by suppressing matrix metalloproteinase-9 activation through the histone acetylation.

    PubMed

    Yeh, Chia-Ming; Lin, Chiao-Wen; Yang, Jia-Sin; Yang, Wei-En; Su, Shih-Chi; Yang, Shun-Fa

    2016-04-19

    Melatonin exerts antimetastatic effects on liver and breast cancer and also inhibits matrix metalloproteinase (MMP) activity. However, the detailed impacts and underlying mechanisms of melatonin on oral cancer cell metastasis are still unclear. This study showed that melatonin attenuated the 12-O-tetradecanoylphorbol-13-acetate-induced migration of oral cancer cell lines, HSC-3 and OECM-1. Zymography, quantitative real-time PCR, and Western blotting analyses revealed that melatonin lessened MMP-9 enzyme activity as well as the expression of MMP-9 mRNA and protein. Furthermore, melatonin suppressed the phosphorylation of the ERK1/2 signalling pathway, which dampened MMP-9 gene transcription by affecting the expression of transcriptional coactivators, such as CREB-binding protein (CREBBP) and E1A binding protein p300 (EP300), and decreasing histone acetylation in HSC-3 and OECM-1 cells. Examinations on clinical samples exhibited that MMP-9, CREBBP, and EP300 were significantly increased in oral cancer tissues. Moreover, the relative level of CREBBP was positively correlated with the expression of MMP-9 and EP300. In conclusion, we demonstrated that melatonin inhibits the motility of HSC-3 and OECM-1 cells in vitro through a molecular mechanism that involves attenuation of MMP-9 expression and activity mediated by decreased histone acetylation. PMID:26980735

  6. TIMP-2 promotes activation of progelatinase A by membrane-type 1 matrix metalloproteinase immobilized on agarose beads.

    PubMed

    Kinoshita, T; Sato, H; Okada, A; Ohuchi, E; Imai, K; Okada, Y; Seiki, M

    1998-06-26

    Membrane-type 1 matrix metalloproteinase (MT1-MMP)/MMP-14 is the activator of progelatinase A (proGelA)/proMMP-2 on the cell surface. However, it was a paradox that a tissue inhibitor of metalloproteinase-2 (TIMP-2), which is an inhibitor of MT1-MMP, is required for proGelA activation by the cells expressing MT1-MMP. In this study, a truncated MT1-MMP having a FLAG-tag sequence at the C terminus (MT1-F) was immobilized onto agarose beads (MT1-F/B) and used to analyze the role of TIMP-2. The proteolytic activity of MT1-F/B against a synthetic peptide substrate was inhibited by TIMP-2 in a dose-dependent manner. In contrast, TIMP-2 promoted the processing of proGelA by MT1-F/B at low concentrations and inhibited it at higher concentrations. TIMP-2 promoted the binding of proGelA to the MT1-F on the beads by forming a trimolecular complex, which was followed by processing of proGelA. A stimulatory effect of TIMP-2 was observed under conditions in which unoccupied MT1-F was still available. Thus, the ternary complex is thought to act as a means to concentrate the substrate to the bead surface and to present it to the neighboring free MT1-F.

  7. VEGF increases the fibrinolytic activity of endothelial cells within fibrin matrices: involvement of VEGFR-2, tissue type plasminogen activator and matrix metalloproteinases.

    PubMed

    Ratel, David; Mihoubi, Samira; Beaulieu, Edith; Durocher, Yves; Rivard, Georges-Etienne; Gingras, Denis; Béliveau, Richard

    2007-01-01

    Proteolysis of fibrin matrices by endothelial cells plays essential roles in the migratory and morphogenic differentiation processes underlying angiogenesis. Using an in vitro fibrinolysis model consisting of human umbilical vein endothelial cells (HUVECs) embedded in a three dimensional fibrin matrix, we show that VEGF, an angiogenic cytokine that plays a crucial role in the onset of angiogenesis, is a potent activator of HUVEC-mediated fibrinolysis. This VEGF-dependent fibrin degradation was completely abrogated by inhibitors of either the plasminogen activator/plasmin or matrix metalloproteinases (MMP) proteolytic systems, suggesting the involvement of both classes of proteases in fibrin degradation. Accordingly, VEGF-induced fibrinolysis correlated with an increase in the expression of tPA and of some MMPs, such as MT2-MMP and was completely blocked by a neutralizing antibody against tPA. Overall, these results indicate that efficient proteolysis of three dimensional fibrin matrices during VEGF-mediated angiogenesis involves a complex interplay between the MMP and plasmin-mediated proteolytic systems. PMID:17512973

  8. Development of CMOS Pixel Sensors with digital pixel dedicated to future particle physics experiments

    NASA Astrophysics Data System (ADS)

    Zhao, W.; Wang, T.; Pham, H.; Hu-Guo, C.; Dorokhov, A.; Hu, Y.

    2014-02-01

    Two prototypes of CMOS pixel sensor with in-pixel analog to digital conversion have been developed in a 0.18 μm CIS process. The first design integrates a discriminator into each pixel within an area of 22 × 33 μm2 in order to meet the requirements of the ALICE inner tracking system (ALICE-ITS) upgrade. The second design features 3-bit charge encoding inside a 35 × 35 μm2 pixel which is motivated by the specifications of the outer layers of the ILD vertex detector (ILD-VXD). This work aims to validate the concept of in-pixel digitization which offers higher readout speed, lower power consumption and less dead zone compared with the column-level charge encoding.

  9. Optical links for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stucci, Stefania

    2016-07-01

    With the expected increase in the instantaneous luminosity of the LHC in the next few years, the off-detector optical read-out system of the outer two layers of the Pixel Detector of the ATLAS experiment will reach its bandwidth limits. The bandwidth will be increased with new optical receivers, which had to be redesigned since commercial solutions could not be used. The new design allows for a wider operational range in terms of data frequency and input optical power to match the on-detector transmitters of the present Pixel Detector. We report on the design and testing of prototypes of these components and the plans for the installation in the Pixel Detector read-out chain in 2015.

  10. Power Studies for the CMS Pixel Tracker

    SciTech Connect

    Todri, A.; Turqueti, M.; Rivera, R.; Kwan, S.; /Fermilab

    2009-01-01

    The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory is carrying out R&D investigations for the upgrade of the power distribution system of the Compact Muon Solenoid (CMS) Pixel Tracker at the Large Hadron Collider (LHC). Among the goals of this effort is that of analyzing the feasibility of alternative powering schemes for the forward tracker, including DC to DC voltage conversion techniques using commercially available and custom switching regulator circuits. Tests of these approaches are performed using the PSI46 pixel readout chip currently in use at the CMS Tracker. Performance measures of the detector electronics will include pixel noise and threshold dispersion results. Issues related to susceptibility to switching noise will be studied and presented. In this paper, we describe the current power distribution network of the CMS Tracker, study the implications of the proposed upgrade with DC-DC converters powering scheme and perform noise susceptibility analysis.

  11. Vivid, full-color aluminum plasmonic pixels

    PubMed Central

    Olson, Jana; Manjavacas, Alejandro; Liu, Lifei; Chang, Wei-Shun; Foerster, Benjamin; King, Nicholas S.; Knight, Mark W.; Nordlander, Peter; Halas, Naomi J.; Link, Stephan

    2014-01-01

    Aluminum is abundant, low in cost, compatible with complementary metal-oxide semiconductor manufacturing methods, and capable of supporting tunable plasmon resonance structures that span the entire visible spectrum. However, the use of Al for color displays has been limited by its intrinsically broad spectral features. Here we show that vivid, highly polarized, and broadly tunable color pixels can be produced from periodic patterns of oriented Al nanorods. Whereas the nanorod longitudinal plasmon resonance is largely responsible for pixel color, far-field diffractive coupling is used to narrow the plasmon linewidth, enabling monochromatic coloration and significantly enhancing the far-field scattering intensity of the individual nanorod elements. The bright coloration can be observed with p-polarized white light excitation, consistent with the use of this approach in display devices. The resulting color pixels are constructed with a simple design, are compatible with scalable fabrication methods, and provide contrast ratios exceeding 100:1. PMID:25225385

  12. Novel effects of sphingosylphosphorylcholine on invasion of breast cancer: Involvement of matrix metalloproteinase-3 secretion leading to WNT activation.

    PubMed

    Kim, Hyun Ji; Kang, Gyeoung Jin; Kim, Eun Ji; Park, Mi Kyung; Byun, Hyun Jung; Nam, Seungyoon; Lee, Ho; Lee, Chang Hoon

    2016-09-01

    Sphingosylphosphorylcholine (SPC) participates in several cellular processes including metastasis. SPC induces keratin reorganization and regulates the viscoelasticity of metastatic cancer cells including PANC-1 cancer cells leading to enhanced migration and invasion. The role of SPC and the relevant mechanism in invasion of breast cell are as yet unknown. SPC dose-dependently induces invasion of breast cancer cells or breast immortalized cells. Reverse transcription polymerase chain reaction and Western blot analyses of MCF10A and ZR-75-1 cells indicated that SPC induces expression and secretion of matrix metalloproteinase-3 (MMP3). From online KMPLOT, relapse free survival is high in patients having low MMP3 expressed basal breast cancer (n=581, p=0.032). UK370106 (MMP3 inhibitor) or gene silencing of MMP3 markedly inhibited the SPC-induced invasion of MCF10A cells. An extracellular signal-regulated kinase (ERK) inhibitor, PD98059, significantly suppressed the secretion and the gelatinolytic activity of MMP3, and invasion in MCF10A cells. Over-expression of ERK1 and ERK2 promoted both the expression and secretion of MMP3. In contrast, gene silencing of ERK1 and ERK2 attenuated the secretion of MMP3 in MCF10A cells. The effects of SPC-induced MMP3 secretion on β-catenin and TCF/lymphoid enhancer factor (LEF) promoter activity were examined since MMP3 indirectly activates canonical Wnt signaling. SPC induced translocation of β-catenin to nucleus and increased TCF/LEF promoter activity. These events were suppressed by UK370106 or PD98059. Wnt inhibitor, FH535 inhibited SPC-induced MMP3 secretion and invasion. Taken together, these results suggest that SPC induces MMP3 expression and secretion via ERK leading to Wnt activation. PMID:27216977

  13. An osteopontin-NADPH oxidase signaling cascade promotes pro-matrix metalloproteinase 9 activation in aortic mesenchymal cells.

    PubMed

    Lai, Chung-Fang; Seshadri, Venkat; Huang, Kane; Shao, Jian-Su; Cai, Jun; Vattikuti, Radhika; Schumacher, Arwyn; Loewy, Arleen P; Denhardt, David T; Rittling, Susan R; Towler, Dwight A

    2006-06-23

    Osteopontin (OPN) is a cytokine upregulated in diabetic vascular disease. To better understand its role in vascular remodeling, we assessed how OPN controls metalloproteinase (MMP) activation in aortic adventitial myofibroblasts (AMFs) and A7r5 vascular smooth muscle cells (VSMCs). By zymography, OPN and tumor necrosis factor (TNF)-alpha preferentially upregulate pro-matrix metalloproteinase 9 (pro-MMP9) activity. TNF-alpha upregulated pro-MMP9 in AMFs isolated from wild-type (OPN(+/+)) mice, but pro-MMP9 induction was abrogated in AMFs from OPN(-/-) mice. OPN treatment of VSMCs enhanced pro-MMP9 activity, and TNF-alpha induction of pro-MMP9 was inhibited by anti-OPN antibody and apocynin. Superoxide and the oxylipid product 8-isoprostaglandin F(2) alpha-isoprostane (8-IsoP) were increased by OPN treatment, and anti-OPN antibody suppressed 8-IsoP production. Like OPN and TNF-alpha, 8-IsoP preferentially activated pro-MMP9. Superoxide, 8-IsoP, and NADPH oxidase 2 (Nox2) subunits were reduced in OPN(-/-) AMFs. Treatment of A7r5 VSMCs with OPN upregulated NADPH oxidase subunit accumulation. OPN structure/function studies mapped these activities to the SVVYGLR heptapeptide motif in the thrombin-liberated human OPN N-terminal domain (SLAYGLR in mouse OPN). Treatment of aortic VSMCs with SVVYGLR upregulated pro-MMP9 activity and restored TNF-alpha activation of pro-MMP9 in OPN(-/-) AMFs. Injection of OPN-deficient OPN(+/-) mice with SVVYGLR peptide upregulated pro-MMP9 activity, 8-IsoP levels, and Nox2 protein levels in aorta and increased panmural superoxide production (dihydroethidium staining). At equivalent hyperglycemia and dyslipidemia, 8-IsoP levels and aortic pro-MMP9 were reduced with complete OPN deficiency in a model of diet-induced diabetes, achieved by comparing OPN(-/-)/LDLR(-/-) versus OPN(+/-)/LDLR(-/-) siblings. Thus, OPN provides a paracrine signal that augments vascular pro-MMP9 activity, mediated in part via superoxide generation and oxylipid

  14. Transcript-activated collagen matrix as sustained mRNA delivery system for bone regeneration.

    PubMed

    Badieyan, Zohreh Sadat; Berezhanskyy, Taras; Utzinger, Maximilian; Aneja, Manish Kumar; Emrich, Daniela; Erben, Reinhold; Schüler, Christiane; Altpeter, Philipp; Ferizi, Mehrije; Hasenpusch, Günther; Rudolph, Carsten; Plank, Christian

    2016-10-10

    Transcript therapies using chemically modified messenger RNAs (cmRNAs) are emerging as safe and promising alternatives for gene and recombinant protein therapies. However, their applications have been limited due to transient translation and relatively low stability of cmRNAs compared to DNA. Here we show that vacuum-dried cmRNA-loaded collagen sponges, termed transcript activated matrices (TAMs), can serve as depots for sustained delivery of cmRNA. TAMs provide steady state protein production for up to six days, and substantial residual expression until 11days post transfection. Another advantage of this technology was nearly 100% transfection efficiency as well as low toxicity in vitro. TAMs were stable for at least 6months at room temperature. Human BMP-2-encoding TAMs induced osteogenic differentiation of MC3T3-E1 cells in vitro and bone regeneration in a non-critical rat femoral bone defect model in vivo. In summary, TAMs are a promising tool for bone regeneration and potentially also for other applications in regenerative medicine and tissue engineering. PMID:27586186

  15. Studying the cytolytic activity of gas plasma with self-signalling phospholipid vesicles dispersed within a gelatin matrix

    NASA Astrophysics Data System (ADS)

    Marshall, Serena E.; Jenkins, A. Toby A.; Al-Bataineh, Sameer A.; Short, Robert D.; Hong, Sung-Ha; Thet, Naing T.; Oh, Jun-Seok; Bradley, James W.; Szili, Endre J.

    2013-05-01

    A synthetic biological sensor was developed to monitor the interaction of plasma with soft, hydrated biological material. It comprises phospholipid vesicles in a hydrated proteinaceous environment comprising 5% (w/v) gelatin. The vesicles contained a self-quenched dye, which was activated by vesicle destruction giving a clear fluorescent switch on. The interaction of bacterial toxins with the sensor was measured in a proof of principle experiment, then the effect of atmospheric plasma jets with the sensor, was studied in order to assess the cytolytic effect of plasma jets in biological systems. When the plasma contacted the gelatin surface perpendicular to the surface, the treatment resulted in the formation of a star-shaped pattern of microchannels that radiated out from the centre of the treatment area within the gelatin matrix, and locally damaged vesicles within the microchannels at a depth of 150 µm below the gelatin surface. Plasma jets applied in parallel to the surface of the matrix resulted in the formation of a single microchannel with damage to the vesicles only evident at the walls of the channel, and a much reduced penetration depth within the gelatin. Our data show that the effects of plasma can be deep in the gelatin material and that the angle of treatment significantly influenced the nature and level of damage to the gelatin and vesicles. Potentially this gelatin model can be used to unravel the roles of different plasma species and the direct effect of whole plasma contact, from those of primary and secondary species—i.e. primary, those emanating directly from the plasma and secondary, those species created in the ‘target’ tissue. This type of insight could be useful in the future development of safe and effective plasma medical technologies.

  16. Development of a CMOS SOI Pixel Detector

    SciTech Connect

    Arai, Y.; Hazumi, M.; Ikegami, Y.; Kohriki, T.; Tajima, O.; Terada, S.; Tsuboyama, T.; Unno, Y.; Ushiroda, Y.; Ikeda, H.; Hara, K.; Ishino, H.; Kawasaki, T.; Miyake, H.; Martin, E.; Varner, G.; Tajima, H.; Ohno, M.; Fukuda, K.; Komatsubara, H.; Ida, J.; /NONE - OKI ELECTR INDUST TOKYO

    2008-08-19

    We have developed a monolithic radiation pixel detector using silicon on insulator (SOI) with a commercial 0.15 {micro}m fully-depleted-SOI technology and a Czochralski high resistivity silicon substrate in place of a handle wafer. The SOI TEG (Test Element Group) chips with a size of 2.5 x 2.5 mm{sup 2} consisting of 20 x 20 {micro}m{sup 2} pixels have been designed and manufactured. Performance tests with a laser light illumination and a {beta} ray radioactive source indicate successful operation of the detector. We also briefly discuss the back gate effect as well as the simulation study.

  17. Design, optimization and evaluation of a "smart" pixel sensor array for low-dose digital radiography

    NASA Astrophysics Data System (ADS)

    Wang, Kai; Liu, Xinghui; Ou, Hai; Chen, Jun

    2016-04-01

    Amorphous silicon (a-Si:H) thin-film transistors (TFTs) have been widely used to build flat-panel X-ray detectors for digital radiography (DR). As the demand for low-dose X-ray imaging grows, a detector with high signal-to-noise-ratio (SNR) pixel architecture emerges. "Smart" pixel is intended to use a dual-gate photosensitive TFT for sensing, storage, and switch. It differs from a conventional passive pixel sensor (PPS) and active pixel sensor (APS) in that all these three functions are combined into one device instead of three separate units in a pixel. Thus, it is expected to have high fill factor and high spatial resolution. In addition, it utilizes the amplification effect of the dual-gate photosensitive TFT to form a one-transistor APS that leads to a potentially high SNR. This paper addresses the design, optimization and evaluation of the smart pixel sensor and array for low-dose DR. We will design and optimize the smart pixel from the scintillator to TFT levels and validate it through optical and electrical simulation and experiments of a 4x4 sensor array.

  18. Matrix metalloprotease activity shapes the magnitude of EPSPs and spike plasticity within the hippocampal CA3 network.

    PubMed

    Wójtowicz, Tomasz; Mozrzymas, Jerzy W

    2014-02-01

    Matrix metalloproteases (MMP) play a pivotal role in long-term synaptic plasticity, learning, and memory. The roles of different MMP subtypes are emerging, but the proteolytic activity of certain MMPs was shown to support these processes through the structural and functional modification of hippocampal Schaeffer collateral and mossy fiber (MF) synapses. However, certain patterns of synaptic activity are additionally associated with non-synaptic changes, such as the scaling of neuronal excitability. However, the extent to which MMPs affect this process remains unknown. We determined whether MMP activity interferes with excitatory post-synaptic potential EPSP-to-spike (E-S) coupling under conditions of varying synaptic activity. We evoked short- and long-term synaptic plasticity at associational/commissural (A/C) synapses of CA3 pyramidal neurons and simultaneously recorded population spikes (PSs) and EPSPs in acute rat (P30-60) brain slices in the presence of various MMP inhibitors. We found that MMP inhibition significantly reduced E-S coupling and shortened the PS latency associated with 4× 100 Hz stimulation or paired burst activity of MF-CA3 and A/C synapses. Moreover, MMP inhibition interfered with the scaling of amplitude of measured signals during high-frequency trains, thus affecting the induction of long-term potentiation (LTP). The inhibition of L-type voltage-gated calcium channels with 20 µM nifedipine or GABA-A receptors with 1-30 µM picrotoxin did not occlude the effects of MMP inhibitors. However, MMP inhibition significantly reduced the LTP of NMDA receptor-mediated EPSPs. Finally, the analysis of LTP saturation with multiple single (1× 100 Hz) or packed (4× 100 Hz) trains indicated that MMPs support E-S coupling evoked by selected synaptic activity patterns and set the ceiling for tetanically evoked E-S LTP. In conclusion, the activity of MMPs, particularly MMP-3, regulated the magnitude of EPSPs and spike plasticity in the CA3 network and may

  19. Matrix metalloproteinase-1 inhibitory activities of Morinda citrifolia seed extract and its constituents in UVA-irradiated human dermal fibroblasts.

    PubMed

    Masuda, Megumi; Murata, Kazuya; Naruto, Shunsuke; Uwaya, Akemi; Isami, Fumiyuki; Matsuda, Hideaki

    2012-01-01

    The objective of this study was to examine whether a 50% ethanolic extract (MCS-ext) of the seeds of Morinda citrifolia (noni) and its constituents have matrix metalloproteinase-1 (MMP-1) inhibitory activity in UVA-irradiated normal human dermal fibroblasts (NHDFs). The MCS-ext (10 μg/mL) inhibited MMP-1 secretion from UVA-irradiated NHDFs, without cytotoxic effects, at 48 h after UV exposure. The ethyl acetate-soluble fraction of MCS-ext was the most potent inhibitor of MMP-1 secretion. Among the constituents of the fraction, a lignan, 3,3'-bisdemethylpinoresinol (1), inhibited the MMP-1 secretion at a concentration of 0.3 μM without cytotoxic effects. Furthermore, 1 (0.3 μM) reduced the level of intracellular MMP-1 expression. Other constituents, namely americanin A (2), quercetin (3) and ursolic acid (4), were inactive. To elucidate inhibition mechanisms of MMP-1 expression and secretion, the effect of 1 on mitogen-activated protein kinases (MAPKs) phosphorylation was examined. Western blot analysis revealed that 1 (0.3 μM) reduced the phosphorylations of p38 and c-Jun-N-terminal kinase (JNK). These results suggested that 1 suppresses intracellular MMP-1 expression, and consequent secretion from UVA-irradiated NHDFs, by down-regulation of MAPKs phosphorylation.

  20. Matrix-addressable, active electrode arrays for neural stimulation using organic semiconductors—cytotoxicity and pilot experiments in vivo

    NASA Astrophysics Data System (ADS)

    Feili, Dara; Schuettler, Martin; Stieglitz, Thomas

    2008-03-01

    Organic field effect transistors can be integrated into micromachined polyimide-based neural stimulation electrode arrays in order to build active switching matrices. With this approach, a matrix of N × M electrode contacts requires only N + M interconnects to a stimulator when active switching elements are used instead of N × M interconnects. In this paper, we demonstrated that pentacene-based organic field effect transistors (OFETs) can be used to drive stimulation currents through neural electrodes in a physiological-like environment. In order to prove the general applicability as an implant material, the cytotoxicity of pentacene was evaluated with respect to potential effects on cell viability. The results of these tests indicate that extracts from pentacene inhibit neither proliferation nor metabolism of the tested mouse fibroblasts. However, some effect on cell spreading was observed when cells were in direct contact to pentacene for 48 h. In pilot experiments it was demonstrated for the very first time that pentacene transistors can be used as switching elements, acting as voltage-controlled current sources, capable of driving currents suitable for electrical stimulation of a peripheral nerve via a tripolar cuff electrode.

  1. Fumigaclavine C, an fungal metabolite, improves experimental colitis in mice via downregulating Th1 cytokine production and matrix metalloproteinase activity.

    PubMed

    Wu, Xue-Feng; Fei, Ming-Jian; Shu, Ren-Geng; Tan, Ren-Xiang; Xu, Qiang

    2005-09-01

    In the present paper, the effect of Fumigaclavine C, a fungal metabolite, on experimental colitis was examined. Fumigaclavine C, when administered intraperitoneally once a day, significantly reduced the weight loss and mortality rate of mice with experimental colitis induced by intrarectally injection of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS). This compound also markedly alleviated the macroscopic and microscopic appearances of colitis. Furthermore, Fumigaclavine C, given both in vivo and in vitro, showed a marked inhibition on the expression of several inflammatory cytokines, including IL-1beta, IL-2, IL-12alpha, IFN-gamma, TNF-alpha as well as MMP-9 in sacral lymph node cells, colonic patch lymphocytes and colitis tissues from the TNBS colitis mice. Meanwhile, the compound caused a dose-dependent reduction in IL-2 and IFN-gamma from the lymphocytes at the protein level and MMP-9 activity. These results suggest that Fumigaclavine C may alleviate experimental colitis mainly via down-regulating the production of Th1 cytokines and the activity of matrix metalloproteinase. PMID:16023606

  2. Fluid Shear Stress Regulates the Invasive Potential of Glioma Cells via Modulation of Migratory Activity and Matrix Metalloproteinase Expression

    PubMed Central

    Qazi, Henry; Shi, Zhong-Dong; Tarbell, John M.

    2011-01-01

    Background Glioma cells are exposed to elevated interstitial fluid flow during the onset of angiogenesis, at the tumor periphery while invading normal parenchyma, within white matter tracts, and during vascular normalization therapy. Glioma cell lines that have been exposed to fluid flow forces in vivo have much lower invasive potentials than in vitro cell motility assays without flow would indicate. Methodology/Principal Findings A 3D Modified Boyden chamber (Darcy flow through collagen/cell suspension) model was designed to mimic the fluid dynamic microenvironment to study the effects of fluid shear stress on the migratory activity of glioma cells. Novel methods for gel compaction and isolation of chemotactic migration from flow stimulation were utilized for three glioma cell lines: U87, CNS-1, and U251. All physiologic levels of fluid shear stress suppressed the migratory activity of U87 and CNS-1 cell lines. U251 motility remained unaltered within the 3D interstitial flow model. Matrix Metalloproteinase (MMP) inhibition experiments and assays demonstrated that the glioma cells depended on MMP activity to invade, and suppression in motility correlated with downregulation of MMP-1 and MMP-2 levels. This was confirmed by RT-PCR and with the aid of MMP-1 and MMP-2 shRNA constructs. Conclusions/Significance Fluid shear stress in the tumor microenvironment may explain reduced glioma invasion through modulation of cell motility and MMP levels. The flow-induced migration trends were consistent with reported invasive potentials of implanted gliomas. The models developed for this study imply that flow-modulated motility involves mechanotransduction of fluid shear stress affecting MMP activation and expression. These models should be useful for the continued study of interstitial flow effects on processes that affect tumor progression. PMID:21637818

  3. Hybrid matrix amplifier

    DOEpatents

    Martens, J.S.; Hietala, V.M.; Plut, T.A.

    1995-01-03

    The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N[times]M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise. 6 figures.

  4. Hybrid matrix amplifier

    DOEpatents

    Martens, Jon S.; Hietala, Vincent M.; Plut, Thomas A.

    1995-01-01

    The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N.times.M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise.

  5. Fully 3D-Integrated Pixel Detectors for X-Rays

    SciTech Connect

    Deptuch, Grzegorz W.; Gabriella, Carini; Enquist, Paul; Grybos, Pawel; Holm, Scott; Lipton, Ronald; Maj, Piotr; Patti, Robert; Siddons, David Peter; Szczygiel, Robert; Yarema, Raymond

    2016-01-01

    The vertically integrated photon imaging chip (VIPIC1) pixel detector is a stack consisting of a 500-μm-thick silicon sensor, a two-tier 34-μm-thick integrated circuit, and a host printed circuit board (PCB). The integrated circuit tiers were bonded using the direct bonding technology with copper, and each tier features 1-μm-diameter through-silicon vias that were used for connections to the sensor on one side, and to the host PCB on the other side. The 80-μm-pixel-pitch sensor was the direct bonding technology with nickel bonded to the integrated circuit. The stack was mounted on the board using Sn–Pb balls placed on a 320-μm pitch, yielding an entirely wire-bond-less structure. The analog front-end features a pulse response peaking at below 250 ns, and the power consumption per pixel is 25 μW. We successful completed the 3-D integration and have reported here. Additionally, all pixels in the matrix of 64 × 64 pixels were responding on well-bonded devices. Correct operation of the sparsified readout, allowing a single 153-ns bunch timing resolution, was confirmed in the tests on a synchrotron beam of 10-keV X-rays. An equivalent noise charge of 36.2 e- rms and a conversion gain of 69.5 μV/e- with 2.6 e- rms and 2.7 μV/e- rms pixel-to-pixel variations, respectively, were measured.

  6. Uncooled infrared detectors toward smaller pixel pitch with newly proposed pixel structure

    NASA Astrophysics Data System (ADS)

    Tohyama, Shigeru; Sasaki, Tokuhito; Endoh, Tsutomu; Sano, Masahiko; Kato, Koji; Kurashina, Seiji; Miyoshi, Masaru; Yamazaki, Takao; Ueno, Munetaka; Katayama, Haruyoshi; Imai, Tadashi

    2013-12-01

    An uncooled infrared (IR) focal plane array (FPA) with 23.5 μm pixel pitch has been successfully demonstrated and has found wide commercial applications in the areas of thermography, security cameras, and other applications. One of the key issues for uncooled IRFPA technology is to shrink the pixel pitch because the size of the pixel pitch determines the overall size of the FPA, which, in turn, determines the cost of the IR camera products. This paper proposes an innovative pixel structure with a diaphragm and beams placed in different levels to realize an uncooled IRFPA with smaller pixel pitch (≦17 μm). The upper level consists of a diaphragm with VOx bolometer and IR absorber layers, while the lower level consists of the two beams, which are designed to be placed on the adjacent pixels. The test devices of this pixel design with 12, 15, and 17 μm pitch have been fabricated on the Si read-out integrated circuit (ROIC) of quarter video graphics array (QVGA) (320×240) with 23.5 μm pitch. Their performances are nearly equal to those of the IRFPA with 23.5 μm pitch. For example, a noise equivalent temperature difference of 12 μm pixel is 63.1 mK for F/1 optics with the thermal time constant of 14.5 ms. Then, the proposed structure is shown to be effective for the existing IRFPA with 23.5 μm pitch because of the improvements in IR sensitivity. Furthermore, the advanced pixel structure that has the beams composed of two levels are demonstrated to be realizable.

  7. STIS CCD Hot Pixel Annealing Cycle 11

    NASA Astrophysics Data System (ADS)

    Proffitt, Charles

    2002-07-01

    The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects. In addition CTE performance is examined by looking for traps in a low signal level flat. Follows on from proposal 8906.

  8. STIS CCD Hot Pixel Annealing Cycle 12

    NASA Astrophysics Data System (ADS)

    Maiz Apellaniz, Jesus

    2003-07-01

    The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects. In addition CTE performance is examined by looking for traps in a low signal level flat. Follows on from proposal 9612.

  9. Digital-pixel focal plane array development

    NASA Astrophysics Data System (ADS)

    Brown, Matthew G.; Baker, Justin; Colonero, Curtis; Costa, Joe; Gardner, Tom; Kelly, Mike; Schultz, Ken; Tyrrell, Brian; Wey, Jim

    2010-01-01

    Since 2006, MIT Lincoln Laboratory has been developing Digital-pixel Focal Plane Array (DFPA) readout integrated circuits (ROICs). To date, four 256 × 256 30 μm pitch DFPA designs with in-pixel analog to digital conversion have been fabricated using IBM 90 nm CMOS processes. The DFPA ROICs are compatible with a wide range of detector materials and cutoff wavelengths; HgCdTe, QWIP, and InGaAs photo-detectors with cutoff wavelengths ranging from 1.6 to 14.5 μm have been hybridized to the same digital-pixel readout. The digital-pixel readout architecture offers high dynamic range, A/C or D/C coupled integration, and on-chip image processing with low power orthogonal transfer operations. The newest ROIC designs support two-color operation with a single Indium bump connection. Development and characterization of the two-color DFPA designs is presented along with applications for this new digital readout technology.

  10. Activated hepatic stellate cells are dependent on self-collagen, cleaved by membrane type 1 matrix metalloproteinase for their growth.

    PubMed

    Birukawa, Naoko Kubo; Murase, Kazuyuki; Sato, Yasushi; Kosaka, Akemi; Yoneda, Akihiro; Nishita, Hiroki; Fujita, Ryosuke; Nishimura, Miyuki; Ninomiya, Takafumi; Kajiwara, Keiko; Miyazaki, Miyono; Nakashima, Yusuke; Ota, Sigenori; Murakami, Yuya; Tanaka, Yasunobu; Minomi, Kenjiro; Tamura, Yasuaki; Niitsu, Yoshiro

    2014-07-18

    Stellate cells are distributed throughout organs, where, upon chronic damage, they become activated and proliferate to secrete collagen, which results in organ fibrosis. An intriguing property of hepatic stellate cells (HSCs) is that they undergo apoptosis when collagen is resolved by stopping tissue damage or by treatment, even though the mechanisms are unknown. Here we disclose the fact that HSCs, normal diploid cells, acquired dependence on collagen for their growth during the transition from quiescent to active states. The intramolecular RGD motifs of collagen were exposed by cleavage with their own membrane type 1 matrix metalloproteinase (MT1-MMP). The following evidence supports this conclusion. When rat activated HSCs (aHSCs) were transduced with siRNA against the collagen-specific chaperone gp46 to inhibit collagen secretion, the cells underwent autophagy followed by apoptosis. Concomitantly, the growth of aHSCs was suppressed, whereas that of quiescent HSCs was not. These in vitro results are compatible with the in vivo observation that apoptosis of aHSCs was induced in cirrhotic livers of rats treated with siRNAgp46. siRNA against MT1-MMP and addition of tissue inhibitor of metalloproteinase 2 (TIMP-2), which mainly inhibits MT1-MMP, also significantly suppressed the growth of aHSCs in vitro. The RGD inhibitors echistatin and GRGDS peptide and siRNA against the RGD receptor αVβ1 resulted in the inhibition of aHSCs growth. Transduction of siRNAs against gp46, αVβ1, and MT1-MMP to aHSCs inhibited the survival signal of PI3K/AKT/IκB. These results could provide novel antifibrosis strategies.

  11. Neovibsanin B increases extracellular matrix proteins in optic nerve head cells via activation of Smad signalling pathway.

    PubMed

    Wang, Zhen; Xu, Wei; Rong, Ao; Lin, Yan; Qiu, Xu-Ling; Qu, Shen; Lan, Xian-Hai

    2015-01-01

    The present study demonstrates the effect of neovibsanin B on the synthesis and deposition of ECM proteins and the signalling pathways used in optic nerve head (ONH) astrocytes and lamina cribrosa (LC) cells. For investigation of the signalling pathway used by neovibsanin B, ONH cells were treated with neovibsanin B. Western blot and immunostaining analyses were used to examine the phosphorylation of proteins involved in Smad and non-Smad signalling pathway. The results revealed that ONH cells on treatment with neovibsanin B showed enhanced synthesis of extracellular matrix (ECM) proteins. Neovibsanin B induced phosphorylation of canonical signalling proteins, Smad2/3. However phosphorylation of non-canonical signalling proteins, extracellular signal-regulated kinases, p38, and c-Jun N-terminal kinases (JNK) 1/2 remained unaffected. There was also increase in co-localization of pSmad2/3 with Co-Smad4 in the nucleus of ONH astrocytes and LC cells indicating activation of the canonical Smad signalling pathway. Treatment of ONH cells with SIS3, inhibitor of Smad3 phosphorylation reversed the neovibsanin B stimulated ECM expression as well as activation of canonical pathway signalling molecules. In addition, inhibition of Smad2 or Smad3 using small interfering RNA (siRNA) also suppressed neovibsanin B stimulated ECM protein synthesis in ONH astrocytes and LC cells. Thus neovibsanin B utilizes the canonical Smad signalling pathway to stimulate ECM synthesis in human ONH cells. The neovibsanin B induced ECM synthesis and activation of the canonical Smad signalling pathway may be due to its effect on transforming growth factor-β2 (TGF-β2). However, further studies are under process to understand the mechanism.

  12. Demonstration of a low-voltage three-transistor-per-pixel CMOS imager based on a pulse-width-modulation readout scheme employed with a one-transistor in-pixel comparator

    NASA Astrophysics Data System (ADS)

    Shishido, S.; Nagahata, I.; Sasaki, T.; Kagawa, K.; Nunoshita, M.; Ohta, J.

    2007-02-01

    To realize a low-voltage CMOS imager with a small pixel size, we have proposed a new pixel structure composed of only three transistors without any circuit sharing technique. The pixel has a gate-common transistor that compares a photodiode voltage on the gate node with a ramp signal on the source node to perform a single-slope A/D conversion based on a pulse-width-modulation pixel-reading scheme. The large gain of the in-pixel comparator contribute to the small input-referred noise and surpress column-to-column fixed-pattern-noise (FPN). Pixel-to-pixel FPN is suppressed by a feedback reset. Our CMOS imager can lower the operating voltage with less degradation of the dynamic range than that of ordinary active pixel sensors. We have fabricated a 128×96-pixel prototype sensor with an on-chip ramp generator and bootstrap circuits in a 0.35-μm CMOS technology, and successfully demonstrated its operations with a 1.5-V single power-supply voltage.

  13. Interleukin-1{beta} regulates cell proliferation and activity of extracellular matrix remodelling enzymes in cultured primary pig heart cells

    SciTech Connect

    Zitta, Karina; Brandt, Berenice; Wuensch, Annegret; Meybohm, Patrick; Bein, Berthold; Steinfath, Markus; Scholz, Jens; Albrecht, Martin

    2010-09-03

    Research highlights: {yields} Levels of IL-1{beta} are increased in the pig myocardium after infarction. {yields} Cultured pig heart cells possess IL-1 receptors. {yields} IL-1{beta} increases cell proliferation of pig heart cells in-vitro. {yields} IL-1{beta} increases MMP-2 and MMP-9 activity in pig heart cells in-vitro. {yields} IL-1{beta} may be important for tissue remodelling events after myocardial infarction. -- Abstract: After myocardial infarction, elevated levels of interleukins (ILs) are found within the myocardial tissue and IL-1{beta} is considered to play a major role in tissue remodelling events throughout the body. In the study presented, we have established a cell culture model of primary pig heart cells to evaluate the effects of different concentrations of IL-1{beta} on cell proliferation as well as expression and activity of enzymes typically involved in tissue remodelling. Primary pig heart cell cultures were derived from three different animals and stimulated with recombinant pig IL-1{beta}. RNA expression was detected by RT-PCR, protein levels were evaluated by Western blotting, activity of matrix metalloproteinases (MMPs) was quantified by gelatine zymography and cell proliferation was measured using colorimetric MTS assays. Pig heart cells express receptors for IL-1 and application of IL-1{beta} resulted in a dose-dependent increase of cell proliferation (P < 0.05 vs. control; 100 ng/ml; 24 h). Gene expression of caspase-3 was increased by IL-1{beta} (P < 0.05 vs. control; 100 ng/ml; 3 h), and pro-caspase-3 but not active caspase was detected in lysates of pig heart cells by Western blotting. MMP-2 gene expression as well as enzymatic activities of MMP-2 and MMP-9 were increased by IL-1{beta} (P < 0.05 vs. control; 100 ng/ml; 3 h for gene expression, 48 and 72 h for enzymatic activities of MMP-2 and MMP-9, respectively). Our in vitro data suggest that IL-1{beta} plays a major role in the events of tissue remodelling in the heart. Combined

  14. A 2D 4×4 Channel Readout ASIC for Pixelated CdTe Detectors for Medical Imaging Applications

    PubMed Central

    Macias-Montero, Jose-Gabriel; Sarraj, Maher; Chmeissani, Mokhtar; Martínez, Ricardo; Puigdengoles, Carles

    2015-01-01

    We present a 16-channel readout integrated circuit (ROIC) with nanosecond-resolution time to digital converter (TDC) for pixelated Cadmium Telluride (CdTe) gamma-ray detectors. The 4 × 4 pixel array ROIC is the proof of concept of the 10 × 10 pixel array readout ASIC for positron-emission tomography (PET) scanner, positron-emission mammography (PEM) scanner, and Compton gamma camera. The electronics of each individual pixel integrates an analog front-end with switchable gain, an analog to digital converter (ADC), configuration registers, and a 4-state digital controller. For every detected photon, the pixel electronics provides the energy deposited in the detector with 10-bit resolution, and a fast trigger signal for time stamp. The ASIC contains the 16-pixel matrix electronics, a digital controller, five global voltage references, a TDC, a temperature sensor, and a band-gap based current reference. The ASIC has been fabricated with TSMC 0.25 μm mixed-signal CMOS technology and occupies an area of 5.3 mm × 6.8 mm. The TDC shows a resolution of 95.5 ps, a precision of 600 ps at full width half maximum (FWHM), and a power consumption of 130 μW. In acquisition mode, the total power consumption of every pixel is 200 μW. An equivalent noise charge (ENC) of 160 e−RMS at maximum gain and negative polarity conditions has been measured at room temperature. PMID:26744545

  15. HEPS-BPIX, a single photon counting pixel detector with a high frame rate for the HEPS project

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Zhang, Jie; Ning, Zhe; Lu, Yunpeng; Fan, Lei; Li, Huaishen; Jiang, Xiaoshan; Lan, Allan K.; Ouyang, Qun; Wang, Zheng; Zhu, Kejun; Chen, Yuanbo; Liu, Peng

    2016-11-01

    China's next generation light source, named the High Energy Photon Source (HEPS), is currently under construction. HEPS-BPIX (HEPS-Beijing PIXel) is a dedicated pixel readout chip that operates in single photon counting mode for X-ray applications in HEPS. Designed using CMOS 0.13 μm technology, the chip contains a matrix of 104×72 pixels. Each pixel measures 150 μm×150 μm and has a counting depth of 20 bits. A bump-bonded prototyping detector module with a 300-μm thick silicon sensor was tested in the beamline of Beijing Synchrotron Radiation Facility. A fast stream of X-ray images was demonstrated, and a frame rate of 1.2 kHz was proven, with a negligible dead time. The test results showed an equivalent noise charge of 115 e- rms after bump bonding and a threshold dispersion of 55 e- rms after calibration.

  16. Adaptive bad pixel correction algorithm for IRFPA based on PCNN

    NASA Astrophysics Data System (ADS)

    Leng, Hanbing; Zhou, Zuofeng; Cao, Jianzhong; Yi, Bo; Yan, Aqi; Zhang, Jian

    2013-10-01

    Bad pixels and response non-uniformity are the primary obstacles when IRFPA is used in different thermal imaging systems. The bad pixels of IRFPA include fixed bad pixels and random bad pixels. The former is caused by material or manufacture defect and their positions are always fixed, the latter is caused by temperature drift and their positions are always changing. Traditional radiometric calibration-based bad pixel detection and compensation algorithm is only valid to the fixed bad pixels. Scene-based bad pixel correction algorithm is the effective way to eliminate these two kinds of bad pixels. Currently, the most used scene-based bad pixel correction algorithm is based on adaptive median filter (AMF). In this algorithm, bad pixels are regarded as image noise and then be replaced by filtered value. However, missed correction and false correction often happens when AMF is used to handle complex infrared scenes. To solve this problem, a new adaptive bad pixel correction algorithm based on pulse coupled neural networks (PCNN) is proposed. Potential bad pixels are detected by PCNN in the first step, then image sequences are used periodically to confirm the real bad pixels and exclude the false one, finally bad pixels are replaced by the filtered result. With the real infrared images obtained from a camera, the experiment results show the effectiveness of the proposed algorithm.

  17. Red Grape Skin Polyphenols Blunt Matrix Metalloproteinase-2 and -9 Activity and Expression in Cell Models of Vascular Inflammation: Protective Role in Degenerative and Inflammatory Diseases.

    PubMed

    Calabriso, Nadia; Massaro, Marika; Scoditti, Egeria; Pellegrino, Mariangela; Ingrosso, Ilaria; Giovinazzo, Giovanna; Carluccio, Maria Annunziata

    2016-08-29

    Matrix metalloproteinases (MMPs) are endopeptidases responsible for the hydrolysis of various components of extracellular matrix. MMPs, namely gelatinases MMP-2 and MMP-9, contribute to the progression of chronic and degenerative diseases. Since gelatinases' activity and expression are regulated by oxidative stress, we sought to evaluate whether supplementation with polyphenol-rich red grape skin extracts modulated the matrix-degrading capacity in cell models of vascular inflammation. Human endothelial and monocytic cells were incubated with increasing concentrations (0.5-25 μg/mL) of Negroamaro and Primitivo red grape skin polyphenolic extracts (NSPE and PSPE, respectively) or their specific components (0.5-25 μmol/L), before stimulation with inflammatory challenge. NSPE and PSPE inhibited, in a concentration-dependent manner, endothelial invasion as well as the MMP-9 and MMP-2 release in stimulated endothelial cells, and MMP-9 production in inflamed monocytes, without affecting tissue inhibitor of metalloproteinases (TIMP)-1 and TIMP-2. The matrix degrading inhibitory capacity was the same for both NSPE and PSPE, despite their different polyphenolic profiles. Among the main polyphenols of grape skin extracts, trans-resveratrol, trans-piceid, kaempferol and quercetin exhibited the most significant inhibitory effects on matrix-degrading enzyme activities. Our findings appreciate the grape skins as rich source of polyphenols able to prevent the dysregulation of vascular remodelling affecting degenerative and inflammatory diseases.

  18. Red Grape Skin Polyphenols Blunt Matrix Metalloproteinase-2 and -9 Activity and Expression in Cell Models of Vascular Inflammation: Protective Role in Degenerative and Inflammatory Diseases.

    PubMed

    Calabriso, Nadia; Massaro, Marika; Scoditti, Egeria; Pellegrino, Mariangela; Ingrosso, Ilaria; Giovinazzo, Giovanna; Carluccio, Maria Annunziata

    2016-01-01

    Matrix metalloproteinases (MMPs) are endopeptidases responsible for the hydrolysis of various components of extracellular matrix. MMPs, namely gelatinases MMP-2 and MMP-9, contribute to the progression of chronic and degenerative diseases. Since gelatinases' activity and expression are regulated by oxidative stress, we sought to evaluate whether supplementation with polyphenol-rich red grape skin extracts modulated the matrix-degrading capacity in cell models of vascular inflammation. Human endothelial and monocytic cells were incubated with increasing concentrations (0.5-25 μg/mL) of Negroamaro and Primitivo red grape skin polyphenolic extracts (NSPE and PSPE, respectively) or their specific components (0.5-25 μmol/L), before stimulation with inflammatory challenge. NSPE and PSPE inhibited, in a concentration-dependent manner, endothelial invasion as well as the MMP-9 and MMP-2 release in stimulated endothelial cells, and MMP-9 production in inflamed monocytes, without affecting tissue inhibitor of metalloproteinases (TIMP)-1 and TIMP-2. The matrix degrading inhibitory capacity was the same for both NSPE and PSPE, despite their different polyphenolic profiles. Among the main polyphenols of grape skin extracts, trans-resveratrol, trans-piceid, kaempferol and quercetin exhibited the most significant inhibitory effects on matrix-degrading enzyme activities. Our findings appreciate the grape skins as rich source of polyphenols able to prevent the dysregulation of vascular remodelling affecting degenerative and inflammatory diseases. PMID:27589705

  19. 4.3 μm quantum cascade detector in pixel configuration.

    PubMed

    Harrer, A; Schwarz, B; Schuler, S; Reininger, P; Wirthmüller, A; Detz, H; MacFarland, D; Zederbauer, T; Andrews, A M; Rothermund, M; Oppermann, H; Schrenk, W; Strasser, G

    2016-07-25

    We present the design simulation and characterization of a quantum cascade detector operating at 4.3μm wavelength. Array integration and packaging processes were investigated. The device operates in the 4.3μm CO2 absorption region and consists of 64 pixels. The detector is designed fully compatible to standard processing and material growth methods for scalability to large pixel counts. The detector design is optimized for a high device resistance at elevated temperatures. A QCD simulation model was enhanced for resistance and responsivity optimization. The substrate illuminated pixels utilize a two dimensional Au diffraction grating to couple the light to the active region. A single pixel responsivity of 16mA/W at room temperature with a specific detectivity D* of 5⋅107 cmHz/W was measured. PMID:27464155

  20. Structural Characterization of Sputtered Silicon Thin Films after Rapid Thermal Annealing for Active-Matrix Organic Light Emitting Diode

    NASA Astrophysics Data System (ADS)

    Mugiraneza, Jean de Dieu; Miyahira, Tomoyuki; Sakamoto, Akinori; Chen, Yi; Okada, Tatsuya; Noguchi, Takashi; Itoh, Taketsugu

    2010-12-01

    The microcrystalline phase obtained by adopting a two-step rapid thermal annealing (RTA) process for rf-sputtered silicon films deposited on thermally durable glass was characterized. The optical properties, surface morphology, and internal stress of the annealed Si films are investigated. As the thermally durable glass substrate allows heating of the deposited films at high temperatures, micro-polycrystalline silicon (micro-poly-Si) films of uniform grain size with a smooth surface and a low internal stress could be obtained after annealing at 750 °C. The thermal stress in the Si films was 100 times lower than that found in the films deposited on conventional glass. Uniform grains with an average grain size of 30 nm were observed by transmission electron microscopy (TEM) in the films annealed at 800 °C. These micro-poly-Si films have potential application for fabrication of uniform and reliable thin film transistors (TFTs) for large scale active-matrix organic light emitting diode (AMOLED) displays.

  1. 3.4-Inch Quarter High Definition Flexible Active Matrix Organic Light Emitting Display with Oxide Thin Film Transistor

    NASA Astrophysics Data System (ADS)

    Hatano, Kaoru; Chida, Akihiro; Okano, Tatsuya; Sugisawa, Nozomu; Inoue, Tatsunori; Seo, Satoshi; Suzuki, Kunihiko; Oikawa, Yoshiaki; Miyake, Hiroyuki; Koyama, Jun; Yamazaki, Shunpei; Eguchi, Shingo; Katayama, Masahiro; Sakakura, Masayuki

    2011-03-01

    In this paper, we report a 3.4-in. flexible active matrix organic light emitting display (AMOLED) display with remarkably high definition (quarter high definition: QHD) in which oxide thin film transistors (TFTs) are used. We have developed a transfer technology in which a TFT array formed on a glass substrate is separated from the substrate by physical force and then attached to a flexible plastic substrate. Unlike a normal process in which a TFT array is directly fabricated on a thin plastic substrate, our transfer technology permits a high integration of high performance TFTs, such as low-temperature polycrystalline silicon TFTs (LTPS TFTs) and oxide TFTs, on a plastic substrate, because a flat, rigid, and thermally-stable glass substrate can be used in the TFT fabrication process in our transfer technology. As a result, this technology realized an oxide TFT array for an AMOLED on a plastic substrate. Furthermore, in order to achieve a high-definition AMOLED, color filters were incorporated in the TFT array and a white organic light-emitting diode (OLED) was combined. One of the features of this device is that the whole body of the device can be bent freely because a source driver and a gate driver can be integrated on the substrate due to the high mobility of an oxide TFT. This feature means “true” flexibility.

  2. A High-Performance Current-Mode Source Driver IC for Mobile Active Matrix Organic Light Emitting Diode Displays

    NASA Astrophysics Data System (ADS)

    Jeong, Il-Hun; Kwon, Oh-Kyong

    2008-03-01

    In this paper, we describe two types of 8-bit current-mode driver ICs with a small area and good performance for applications high accuracy current-mode digital-to-analog converters (DACs), and improved channel-to-channel uniformity for active matrix organic light-emitting diode (AMOLED) displays. One uses the proposed current steering DAC (type A), which is an improved architecture of a binary-weighted DAC, and the other uses a DAC that is a combination of a thermometer-decoded of the DAC and a binary-weighted type. The measured results show that the peak integral nonlinearity (INL) is within ±0.5 the least significant bit (LSB), the peak differential nonlinearity (DNL) is within ±0.5 LSB, and the nonuniformity of output current among channels and chips is within ±0.5 LSB. The size of the driver IC is 15,820 ×1,500 µm2 and the total power consumption of the current-mode driver IC is less than 9 mW when the display has full-white pattern with a luminance of 150 cd/m2. The chip area and power consumption with the proposed current DAC are reduced by 26 and 10%, respectively, compared with those of conventional driver ICs with a fully binary-weighted DAC.

  3. Investigation of Pattern-Induced Brightness Non-uniformity in Active-Matrix Organic Light-Emitting Diode Displays

    NASA Astrophysics Data System (ADS)

    Kim, Kyoung-Bo; Park, Hye-Hyang; Kwon, Ohseob; Kim, Moojin; Lee, Ki-Yong; Park, Yongwoo; Choi, JongHyun; Yu, CheolHo; Kim, Hye-Dong; Kim, Sung Chul; Chung, Ho-Kyoon

    2008-01-01

    We recently improved the brightness non-uniformity in active-matrix organic light-emitting diode (AMOLED) regarding non-uniform laser energy distribution by applying a “shot mixing” technique in sequential lateral solidification (SLS) method. Although the new SLS technique was employed, another brightness non-uniformity that appeared as oblique lines on AMOLED panels became a crucial issue. In this work, we attempted to investigate the origins of the non-uniformity. Our systematic analysis on the oblique lines revealed that the line type non-uniformity was attributed to both the SLS process and the thin-film transistor (TFT) fabrication processes. In particular, we found that such oblique patterns might be related to moiré patterns that appear when primary grain boundaries aligned in a repetitive pattern is placed over other repetitive TFT patterns such as metal lines. We adopted a method to diminish the moiré pattern type non-uniformity by applying top emission TFT structure.

  4. Optimal Topology and Experimental Evaluation of Piezoelectric Materials for Actively Shunted General Electric Polymer Matrix Fiber Composite Blades

    NASA Technical Reports Server (NTRS)

    Choi, Benjamin B.; Duffy, Kirsten; Kauffman, Jeffrey L.; Kray, Nicholas

    2012-01-01

    NASA Glenn Research Center, in collaboration with GE Aviation, has begun the development of a smart adaptive structure system with piezoelectric (PE) transducers to improve composite fan blade damping at resonances. Traditional resonant damping approaches may not be realistic for rotating frame applications such as engine blades. The limited space in which the blades reside in the engine makes it impossible to accommodate the circuit size required to implement passive resonant damping. Thus, a novel digital shunt scheme has been developed to replace the conventional electric passive shunt circuits. The digital shunt dissipates strain energy through the load resistor on a power amplifier. General Electric (GE) designed and fabricated a variety of polymer matrix fiber composite (PMFC) test specimens. Investigating the optimal topology of PE sensors and actuators for each test specimen has revealed the best PE transducer location for each target mode. Also a variety of flexible patches, which can conform to the blade surface, have been tested to identify the best performing PE patch. The active damping control achieved significant performance at target modes. This work has been highlighted by successful spin testing up to 5000 rpm of subscale GEnx composite blades in Glenn s Dynamic Spin Rig.

  5. Active site specificity profiling datasets of matrix metalloproteinases (MMPs) 1, 2, 3, 7, 8, 9, 12, 13 and 14

    PubMed Central

    Eckhard, Ulrich; Huesgen, Pitter F.; Schilling, Oliver; Bellac, Caroline L.; Butler, Georgina S.; Cox, Jennifer H.; Dufour, Antoine; Goebeler, Verena; Kappelhoff, Reinhild; auf dem Keller, Ulrich; Klein, Theo; Lange, Philipp F.; Marino, Giada; Morrison, Charlotte J.; Prudova, Anna; Rodriguez, David; Starr, Amanda E.; Wang, Yili; Overall, Christopher M.

    2016-01-01

    The data described provide a comprehensive resource for the family-wide active site specificity portrayal of the human matrix metalloproteinase family. We used the high-throughput proteomic technique PICS (Proteomic Identification of protease Cleavage Sites) to comprehensively assay 9 different MMPs. We identified more than 4300 peptide cleavage sites, spanning both the prime and non-prime sides of the scissile peptide bond allowing detailed subsite cooperativity analysis. The proteomic cleavage data were expanded by kinetic analysis using a set of 6 quenched-fluorescent peptide substrates designed using these results. These datasets represent one of the largest specificity profiling efforts with subsequent structural follow up for any protease family and put the spotlight on the specificity similarities and differences of the MMP family. A detailed analysis of this data may be found in Eckhard et al. (2015) [1]. The raw mass spectrometry data and the corresponding metadata have been deposited in PRIDE/ProteomeXchange with the accession number PXD002265. PMID:26981551

  6. Activated matrix metalloproteinase-8 in saliva as diagnostic test for periodontal disease? A case-control study.

    PubMed

    Izadi Borujeni, Susan; Mayer, Matthias; Eickholz, Peter

    2015-12-01

    Untreated periodontal disease may influence general health. However, how may a physician, who is not trained in periodontal probing, detect untreated periodontitis? Activated matrix metalloproteinase-8 (aMMP-8) in saliva correlates with periodontal probing parameters. Thus, sensitivity and specificity of a chair-side test for aMMP-8 to detect periodontitis were evaluated. Thirty cases [untreated chronic periodontitis (ChP); 15 generalized moderate and 15 generalized severe] and 30 controls [probing depths (PD) ≤3 mm, vertical probing attachment level (PAL-V) ≤2 mm at <30 % of sites) were examined periodontally (PD, PAL-V, bleeding on probing). Subsequently, the aMMP-8 test was performed. The test kit becomes positive with ≥25 ng/ml aMMP-8 in the sample. The aMMP-8 test was positive in 87 % of ChP and in 40 % of controls. That corresponds to a sensitivity of 87 % and a specificity of 60 %. The sensitivity to detect generalized severe ChP was 93 % (60 % specificity). Backward stepwise logistic regression analysis to explain positive aMMP-8 tests identified exclusively ChP with an odds ratio of 9.8 (p < 0.001). Positive results of the aMMP-8 test significantly correlate with generalized ChP. The aMMP-8 test may be used by physicians to detect periodontitis in their patients.

  7. Orally administered betaine reduces photodamage caused by UVB irradiation through the regulation of matrix metalloproteinase-9 activity in hairless mice.

    PubMed

    Im, A-Rang; Lee, Hee Jeong; Youn, Ui Joung; Hyun, Jin Won; Chae, Sungwook

    2016-01-01

    Betaine is widely distributed in plants, microorganisms, in several types of food and in medical herbs, including Lycium chinense. The administration of 100 mg betaine/kg body weight/day is an effective strategy for preventing ultraviolet irradiation‑induced skin damage. The present study aimed to determine the preventive effects of betaine on ultraviolet B (UVB) irradiation‑induced skin damage in hairless mice. The mice were divided into three groups: Control (n=5), UVB‑treated vehicle (n=5) and UVB‑treated betaine (n=5) groups. The level of irradiation was progressively increased between 60 mJ/cm2 per exposure at week 1 (one minimal erythematous dose = 60 mJ/cm2) and 90 mJ/cm2 per exposure at week 7. The formation of wrinkles significantly increased following UVB exposure in the UVB‑treated vehicle group. However, treatment with betaine suppressed UVB‑induced wrinkle formation, as determined by the mean length, mean depth, number, epidermal thickness and collagen damage. Furthermore, oral administration of betaine also inhibited the UVB‑induced expression of mitogen‑activated protein kinase kinase (MEK), extracellular signal‑regulated kinase (ERK), and matrix metalloproteinase‑9 (MMP‑9). These findings suggested that betaine inhibits UVB‑induced skin damage by suppressing increased expression of MMP‑9 through the inhibition of MEK and ERK.

  8. Optimal topology and experimental evaluation of PE materials for actively shunted GE polymer matrix fiber composite blades

    NASA Astrophysics Data System (ADS)

    Choi, Benjamin B.; Duffy, Kirsten; Kauffman, Jeffrey L.; Kray, Nicholas

    2012-04-01

    NASA Glenn Research Center (GRC), in collaboration with GE Aviation, has begun the development of a smart adaptive structure system with piezoelectric transducers to improve composite fan blade damping at resonances. Traditional resonant damping approaches may not be realistic for rotating frame applications such as engine blades. The limited space in which the blades reside in the engine makes it impossible to accommodate the circuit size required to implement passive resonant damping. Thus, we have developed a novel digital shunt scheme to replace the conventional electric passive shunt circuits. The digital shunt dissipates strain energy through the load capacitor on a power amplifier. GE designed and fabricated a variety of polymer matrix fiber composite (PMFC) test specimens. We investigated the optimal topology of PE sensors and actuators for each test specimen to discover the best PE transducer location for each target mode. Also a variety of flexible patches, which can conform to the blade surface, have been tested to identify the best performing piezoelectric patch. The active damping control achieved significant performance at target modes. This work has been highlighted by successful spin testing up to 5,000 rpm of subscale GEnx composite blades in GRC's Dynamic Spin Rig.

  9. Pesticide-Exposure Matrix

    Cancer.gov

    The "Pesticide-exposure Matrix" was developed to help epidemiologists and other researchers identify the active ingredients to which people were likely exposed when their homes and gardens were treated for pests in past years.

  10. Design Methodology: ASICs with complex in-pixel processing for Pixel Detectors

    SciTech Connect

    Fahim, Farah

    2014-10-31

    The development of Application Specific Integrated Circuits (ASIC) for pixel detectors with complex in-pixel processing using Computer Aided Design (CAD) tools that are, themselves, mainly developed for the design of conventional digital circuits requires a specialized approach. Mixed signal pixels often require parasitically aware detailed analog front-ends and extremely compact digital back-ends with more than 1000 transistors in small areas below 100μm x 100μm. These pixels are tiled to create large arrays, which have the same clock distribution and data readout speed constraints as in, for example, micro-processors. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout.

  11. Reading a GEM with a VLSI pixel ASIC used as a direct charge collecting anode

    NASA Astrophysics Data System (ADS)

    Bellazzini, R.; Angelini, F.; Baldini, L.; Bitti, F.; Brez, A.; Ceccanti, M.; Latronico, L.; Massai, M. M.; Minuti, M.; Omodei, N.; Razzano, M.; Sgro, C.; Spandre, G.; Costa, E.; Soffitta, P.

    2004-12-01

    In MicroPattern Gas Detectors (MPGD) when the pixel size is below 100 micron and the number of pixels is large (above 1000) it is virtually impossible to use the conventional PCB read-out approach to bring the signal charge from the individual pixel to the external electronics chain. For this reason a custom CMOS array of 2101 active pixels with 80 micron pitch, directly used as the charge collecting anode of a GEM amplifying structure, has been developed and built. Each charge collecting pad, hexagonally shaped, realized using the top metal layer of a deep submicron VLSI technology is individually connected to a full electronics chain (pre-amplifier, shaping-amplifier, sample and hold, multiplexer) which is built immediately below it by using the remaining five active layers. The GEM and the drift electrode window are assembled directly over the chip so the ASIC itself becomes the pixelized anode of a MicroPattern Gas Detector. With this approach, for the first time, gas detectors have reached the level of integration and resolution typical of solid state pixel detectors. Results from the first tests of this new read-out concept are presented. An Astronomical X-Ray Polarimetry application is also discussed.

  12. Exploring the limits of identifying sub-pixel thermal features using ASTER TIR data

    USGS Publications Warehouse

    Vaughan, R.G.; Keszthelyi, L.P.; Davies, A.G.; Schneider, D.J.; Jaworowski, C.; Heasler, H.

    2010-01-01

    Understanding the characteristics of volcanic thermal emissions and how they change with time is important for forecasting and monitoring volcanic activity and potential hazards. Satellite instruments view volcanic thermal features across the globe at various temporal and spatial resolutions. Thermal features that may be a precursor to a major eruption, or indicative of important changes in an on-going eruption can be subtle, making them challenging to reliably identify with satellite instruments. The goal of this study was to explore the limits of the types and magnitudes of thermal anomalies that could be detected using satellite thermal infrared (TIR) data. Specifically, the characterization of sub-pixel thermal features with a wide range of temperatures is considered using ASTER multispectral TIR data. First, theoretical calculations were made to define a "thermal mixing detection threshold" for ASTER, which quantifies the limits of ASTER's ability to resolve sub-pixel thermal mixing over a range of hot target temperatures and % pixel areas. Then, ASTER TIR data were used to model sub-pixel thermal features at the Yellowstone National Park geothermal area (hot spring pools with temperatures from 40 to 90 ??C) and at Mount Erebus Volcano, Antarctica (an active lava lake with temperatures from 200 to 800 ??C). Finally, various sources of uncertainty in sub-pixel thermal calculations were quantified for these empirical measurements, including pixel resampling, atmospheric correction, and background temperature and emissivity assumptions.

  13. Transdermal delivery of Diltiazem HCl from matrix film: Effect of penetration enhancers and study of antihypertensive activity in rabbit model

    PubMed Central

    Parhi, Rabinarayan; Suresh, Padilam

    2015-01-01

    The present investigation focused on the development of Diltiazem HCl (DTH) matrix film and its characterization by in-vitro, ex-vivo and in-vivo methods. Films were prepared by solvent casting method by taking different ratios of hydroxypropyl methylcellulose K4M (HPMC K4M) and Eudragit RS100. Various parameters o