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Sample records for chemically amplified resist

  1. New polysiloxanes for chemically amplified resist applications

    NARCIS (Netherlands)

    vandeGrampel, JC; Puyenbroek, R; Meetsma, A; Rousseeuw, BAC; vanderDrift, EWJM; Reichmanis, E; Ober, CK; MacDonald, SA; Iwayanagi, T; Nishikubo, T

    1995-01-01

    New polymers have been developed for application in bilayer resist systems. The products are sensitive for e-beam and DW exposure via chemical amplification and contain both silicon and acid-labile groups. Incorporation of silicon, necessary for a high resistance to reactive ion etching (RIE) in

  2. High sensitivity chemically amplified EUV resists through enhanced EUV absorption

    Science.gov (United States)

    Ongayi, Owendi; Christianson, Matthew; Meyer, Matthew; Coley, Suzanne; Valeri, David; Kwok, Amy; Wagner, Mike; Cameron, Jim; Thackeray, Jim

    2012-03-01

    Resolution, line edge roughness, sensitivity and low outgassing are the key focus points for extreme ultraviolet (EUV) resist materials. Sensitivity has become increasingly important so as to address throughput concerns in device manufacturing and compensate for the low power of EUV sources. Recent studies have shown that increasing the polymer linear absorption absorption coefficient in EUV resists translates to higher acid generation efficiency and good pattern formation. In this study, novel high absorbing polymer platforms are evaluated. The contributing effect of the novel absorbing chromophore to the resultant chemically amplified photoresist is evaluated and compared with a standard methacrylate PAG Bound Polymer (PBP) platform. We report that by increasing EUV absorption, we cleanly resolved 17 nm 1:1 line space can be achieved at a sensitivity of 14.5 mJ/cm2, which is consistent with dose requirements dictated by the ITRS roadmap. We also probe the effect of fluorinated small molecule additives on acid yield generation (Dil C) at EUV of a PBP platform.

  3. Stochastic effects in 11 nm imaging of extreme ultraviolet lithography with chemically amplified resists

    Science.gov (United States)

    Kozawa, Takahiro; Santillan, Julius Joseph; Itani, Toshiro

    2014-03-01

    The resolution of extreme ultraviolet (EUV) lithography with chemically amplified resist processes has reached 16 nm (half-pitch). The development of chemically amplified resists is ongoing toward the 11 nm node. However, the stochastic effects are increasingly becoming a significant concern with the continuing shrinkage of features. In this study, the fluctuation of protected unit distribution caused by the stochastic effects during image formation was investigated assuming line-and-space patterns with 11 nm half-pitch. Contrary to expectations, the standard deviation of the number of protected units connected to a polymer after postexposure baking (PEB) did not differ from that for 16 nm half-pitch. The standard deviation after PEB increased with the effective reaction radius for deprotection and the initial standard deviation before PEB. Because of the severe requirements for resist processes, the stochastic effects in chemical reactions should be taken into account in the design of next-generation resists.

  4. Tailoring of a photoactive compound for non-chemically amplified 248-nm resist formulations

    Science.gov (United States)

    Leeson, Michael J.; Pawloski, Adam R.; Levering, Vrad; Yueh, Wang; Willson, C. Grant

    1997-07-01

    Several approaches toward the design of non-chemically amplified deep UV resists have been reported using different photoactive compounds and resins. Diazo-dione chromophores are particularly attractive for this application, but the keto- ketenes derived from their photolysis are more reactive than those derived from the analogous diazonaphthoquinones. Specifically, the 30-diazo-4-ketocoumarin chromophore has been identified as a promising candidate around which to design a non-chemically amplified 248 nm resist. In order to optimize the design of this system, the influence of both electronic and steric influences on the rate of reaction of the ketene with novolac resin has been studied. These experiments were carried out using a low temperature matrix isolation FT-IR technique similar to that previously reported. The reaction of the ketene with the resin hydroxyl group follows pseudo first order kinetics and the rate constant is dependent on the substituents and the substitution pattern on the coumarin.

  5. Continuous evolution of lithographic films through process steps: an example with 193 chemically amplified resists

    Science.gov (United States)

    Derrough, Samir; Tiron, Raluca; Perret, Damien; Thackeray, James W.; Sourd, Claire; Paniez, Patrick

    2010-04-01

    Chemically Amplified resists are complex systems. If the main mechanisms implied have already been described, the challenge to even better control and model these formulations remains important as performance requirements become more and more stringent and critical dimensions get smaller and smaller. This paper tries to assess and deconvolute some of the main potential mechanisms involved during the process of a 193 nm chemically amplified resist, before correlating them with the final lithographic results obtained. A formulation was selected in order to offer a large range of film physical properties, thus allowing the resist film to switch from non-annealing to annealing conditions. The use of thermal analysis as the main characterization technique allowed correlation between the variations in physico-chemical properties and process conditions. This investigation also included a study of the behavior of some additives during bake steps. In so doing, it became possible to correlate the variations of the resist properties under different bake conditions to the changes in its final lithographic performance, i.e. contrast, sensitivity and line edge roughness.

  6. Progress in resolution, sensitivity, and critical dimensional uniformity of EUV chemically amplified resists

    Science.gov (United States)

    Thackeray, James; Cameron, James; Jain, Vipul; LaBeaume, Paul; Coley, Suzanne; Ongayi, Owendi; Wagner, Mike; Rachford, Aaron; Biafore, John

    2013-03-01

    This paper will discuss further progress obtained at Dow for the improvement of the Resolution, Contact critical dimension uniformity(CDU), and Sensitivity of EUV chemically amplified resists. For resolution, we have employed the use of polymer-bound photoacid generator (PBP) concept to reduce the intrinsic acid diffusion that limits the ultimate resolving capability of CA resists. For CDU, we have focused on intrinsic dissolution contrast and have found that the photo-decomposable base (PDB) concept can be successfully employed. With the use of a PDB, we can reduce CDU variation at a lower exposure energy. For sensitivity, we have focused on more efficient EUV photon capture through increased EUV absorption, as well as more highly efficient PAGs for greater acid generating efficiency. The formulation concepts will be confirmed using Prolith stochastic resist modeling. For the 26nm hp contact holes, we get excellent overall process window with over 280nm depth of focus for a 10% exposure latitude Process window. The 1sigma Critical dimension uniformity [CDU] is 1.1 nm. We also obtain 20nm hp contact resolution in one of our new EUV resists.

  7. Dry etching of chrome for photomasks for 100-nm technology using chemically amplified resist

    Science.gov (United States)

    Mueller, Mark; Komarov, Serguie; Baik, Ki-Ho

    2002-07-01

    Photo mask etching for the 100nm technology node places new requirements on dry etching processes. As the minimum-size features on the mask, such as assist bars and optical proximity correction (OPC) patterns, shrink down to 100nm, it is necessary to produce etch CD biases of below 20nm in order to reproduce minimum resist features into chrome with good pattern fidelity. In addition, vertical profiles are necessary. In previous generations of photomask technology, footing and sidewall profile slope were tolerated, since this dry etch profile was an improvement from wet etching. However, as feature sizes shrink, it is extremely important to select etch processes which do not generate a foot, because this will affect etch linearity and also limit the smallest etched feature size. Chemically amplified resist (CAR) from TOK is patterned with a 50keV MEBES eXara e-beam writer, allowing for patterning of small features with vertical resist profiles. This resist is developed for raster scan 50 kV e-beam systems. It has high contrast, good coating characteristics, good dry etch selectivity, and high environmental stability. Chrome etch process development has been performed using Design of Experiments to optimize parameters such as sidewall profile, etch CD bias, etch CD linearity for varying sizes of line/space patterns, etch CD linearity for varying sizes of isolated lines and spaces, loading effects, and application to contact etching.

  8. High-resolution etching of MoSi using electron beam patterned chemically amplified resist

    Science.gov (United States)

    Mueller, Mark; Komarov, Serguei; Baik, Ki-Ho

    2003-08-01

    High resolution etching of MoSi for photomask processing places new requirements on etching processes. As resist features are sized to 100 nm and below, it is first necessary to duplicate these features first into a chrome over-layer. After resist is stripped, this chrome over-layer is used for etching MoSi. Both chrome and MoSi etched profiles require near-vertical sidewalls, good CD (critical dimension) uniformity, good linearity, and CD mean-to-target (MTT). Additional requirements of etched MoSi include minimal roughness on exposed quartz, selectivity to chrome and quartz, phase angle target and phase angle uniformity, etch depth global uniformity, and etch depth uniformity as a function of feature size. An ETEC integrated process is used for the application of resist, patterning, and all subsequent processing. Chemically amplified resist is patterned with the 50 kV MEBES Quadra or MEBES eXara raster scan electron beam writer, allowing for patterning of small features with vertical resist profiles. Plates are etched in a Tetra photomask etch system for projecting resist images into chrome and MoSi. Etch processes have been developed specifically for etching small features in order to meet the requirements of 65 nm node lithography. An optimized etch process window is capable of patterning MoSi features below 100 nm sizes with near-vertical sidewall, 1 um. Excellent CD uniformity and CD etch loading performance are demonstrated. Micro-profilometry is employed to measure the MoSi etch depths of features of varying sizes, and to quantify the effect of loading on MoSi etch depth. SEM micrographs illustrate sidewall profiles resulting from small feature etching.

  9. Chemically amplified i-line positive resist for next-generation flat panel display

    Science.gov (United States)

    Lee, Hsing-Chieh; Lu, Ying-Hao; Huang, Shin-Yih; Lan, Wei-Jen; Hanabata, Makoto

    2017-03-01

    Traditional diazonaphthoquinone (DNQ) positive photoresists are widely used for TFT-LCD array process. Current LTPS technology has more than 600ppi resolution is required for small or middle-sized TFT liquid crystal display panels. One of the ways to enhance resolution is to apply i-line single exposure system instead of traditional g/h/ibroadband exposure system. We have been developing i-line chemically amplified photoresist ECA 200 series for the next generation flat panel display (FPD). ECA 200 consists of three components: a phenol resin, a photo acid generator and dissolution enhancer. We applied two different types of dissolution enhancers with two different kinds of protected groups to our resist materials. As a result, we achieved higher sensitivity, higher resolution, less footing of the resist profile and reduced standing wave effect compared with traditional DNQ photoresists. In addition, we have found further property of photoresist that does not need post exposure bake (PEB) process. This resist has a great advantage at most of current panel plants without PEB process.

  10. Sub-50 nm metrology on extreme ultra violet chemically amplified resist--A systematic assessment.

    Science.gov (United States)

    Maas, D J; Fliervoet, T; Herfst, R; van Veldhoven, E; Meessen, J; Vaenkatesan, V; Sadeghian, H

    2015-10-01

    With lithographic patterning dimensions decreasing well below 50 nm, it is of high importance to understand metrology at such small scales. This paper presents results obtained from dense arrays of contact holes (CHs) with various Critical Dimension (CD) between 15 and 50 nm, as patterned in a chemically amplified resist using an ASML EUV scanner and measured at ASML and TNO. To determine the differences between various (local) CD metrology techniques, we conducted an experiment using optical scatterometry, CD-Scanning Electron Microscopy (CD-SEM), Helium ion Microscopy (HIM), and Atomic Force Microscopy (AFM). CD-SEM requires advanced beam scan strategies to mitigate sample charging; the other tools did not need that. We discuss the observed main similarities and differences between the various techniques. To this end, we assessed the spatial frequency content in the raw images for SEM, HIM, and AFM. HIM and AFM resolve the highest spatial frequencies, which are attributed to the more localized probe-sample interaction for these techniques. Furthermore, the SEM, HIM, and AFM waveforms are analyzed in detail. All techniques show good mutual correlation, albeit the reported CD values systematically differ significantly. HIM systematically reports a 25% higher CD uniformity number than CD-SEM for the same arrays of CHs, probably because HIM has a higher resolution than the CD-SEM used in this assessment. A significant speed boost for HIM and AFM is required before these techniques are to serve the demanding industrial metrology applications like optical critical dimension and CD-SEM do nowadays.

  11. Heavy metal incorporated helium ion active hybrid non-chemically amplified resists: Nano-patterning with low line edge roughness

    Science.gov (United States)

    Reddy, Pulikanti Guruprasad; Thakur, Neha; Lee, Chien-Lin; Chien, Sheng-Wei; Pradeep, Chullikkattil P.; Ghosh, Subrata; Tsai, Kuen-Yu; Gonsalves, Kenneth E.

    2017-08-01

    Helium (He) ion lithography is being considered as one of the most promising and emerging technology for the manufacturing of next generation integrated circuits (ICs) at nanolevel. However, He-ion active resists are rarely reported. In this context, we are introducing a new non-chemically amplified hybrid resist (n-CAR), MAPDSA-MAPDST, for high resolution He-ion beam lithography (HBL) applications. In the resist architecture, 2.15 % antimony is incorporated as heavy metal in the form of antimonate. This newly developed resists has successfully used for patterning 20 nm negative tone features at a dose of 60 μC/cm2. The resist offered very low line edge roughness (1.27±0.31 nm) for 20 nm line features. To our knowledge, this is the first He-ion active hybrid resist for nanopatterning. The contrast (γ) and sensitivity (E0) of this resist were calculated from the contrast curve as 0.73 and 7.2 μC/cm2, respectively.

  12. Heavy metal incorporated helium ion active hybrid non-chemically amplified resists: Nano-patterning with low line edge roughness

    Directory of Open Access Journals (Sweden)

    Pulikanti Guruprasad Reddy

    2017-08-01

    Full Text Available Helium (He ion lithography is being considered as one of the most promising and emerging technology for the manufacturing of next generation integrated circuits (ICs at nanolevel. However, He-ion active resists are rarely reported. In this context, we are introducing a new non-chemically amplified hybrid resist (n-CAR, MAPDSA-MAPDST, for high resolution He-ion beam lithography (HBL applications. In the resist architecture, 2.15 % antimony is incorporated as heavy metal in the form of antimonate. This newly developed resists has successfully used for patterning 20 nm negative tone features at a dose of 60 μC/cm2. The resist offered very low line edge roughness (1.27±0.31 nm for 20 nm line features. To our knowledge, this is the first He-ion active hybrid resist for nanopatterning. The contrast (γ and sensitivity (E0 of this resist were calculated from the contrast curve as 0.73 and 7.2 μC/cm2, respectively.

  13. Real Time Monitoring of NH3 Concentration Using Diffusion Scrubber Sampling Technique and Result of Application to the Processing of Chemically Amplified Resists

    Science.gov (United States)

    Park, Jungchul; Bae, Eunyoung; Park, Chungeun; Han, Woosung; Koh, Youngbum; Lee, Moonyoung; Lee, Jonggil

    1995-12-01

    The application of chemically amplified resist is known to cause a problem in the accurate measurement of the concentration of basic gas species ( NH3, N-methylpyrrolidone (NMP)) in a clean room environment because it is sensitive to its environment. Among various methods of measurement, diffusion scrubber sampling method was selected and tested. The environmental sensitivity of a commercial chemically amplified resist, APEX-E, was also tested. For the concentration measurement, the method proved to be suitable for automation and good for measuring NH3 concentration as low as the sub ppb level (limit of detection ˜0.08 ppb). Some measurement results concerning various aspects of application are presented. Test results of the environmental stability of chemically amplified resists showed that NH3 concentration should be controlled to at least under 7.5 ppb for maintaining the process stability.

  14. New non-chemically amplified molecular resist design with switchable sensitivity for multi-lithography applications and nanopatterning

    Science.gov (United States)

    Thakur, Neha; Guruprasad Reddy, Pulikanti; Nandi, Santu; Yogesh, Midathala; Sharma, Satinder K.; Pradeep, Chullikkattil P.; Ghosh, Subrata; Gonsalves, Kenneth E.

    2017-12-01

    The development of new photoresist materials for multi-lithography applications is crucial but a challenging task for semiconductor industries. During the last few decades, given the need for new resists to meet the requirements of semiconductor industries, several research groups have developed different resist materials for specific lithography applications. In this context, we have successfully synthesized a new molecular non-chemically amplified resist (n-CAR) (C3) based on the functionalization of aromatic hydroxyl core (4,4‧-(9H-fluorene-9,9-diyl)diphenol) with radiation sensitive sulfonium triflates for various lithography applications. While, micron scale features have been developed using i-line (365 nm) and DUVL (254 nm) exposure tools, electron beam studies on C3 thin films enabled us to pattern 20 nm line features with L/3S (line/space) characteristics on the silicon substrate. The sensitivity and contrast were calculated from the contrast curve analysis as 280 µC cm‑2 and 0.025 respectively. Being an important parameter for any newly developed resists, the line edge roughness (LER) of 30 nm (L/5S) features were calculated, using SUMMIT metrology package, to be 3.66  ±  0.3 nm and found to be within the acceptable range. AFM analysis further confirmed 20 nm line width with smooth pattern wall. No deformation of patterned features was observed during AFM analysis which indicated good adhesion property between patterned resists and silicon substrates.

  15. Implementing chemically amplified resist to 10kV raster e-beam process in photomask manufacturing

    Science.gov (United States)

    Kim, Sook-Kyeong; Kim, Byung-Gook; Moon, Seong-Yong; Choi, Sung-Woon; Han, Woo-Sung

    2005-06-01

    CAR(Chemically amplified resist) is widely used in 50keV VSB (Variable Shaped Beam) e-beam process in photomask manufacturing due to its advantage of high sensitivity which gives to reduced writing time compared to non-CAR. The 10kV raster e-beam system, however, is spread out already worldwide and plays a important role till now in middle grade mask-making. Conventionally the non-CAR like ZEP7000 has been applied to the 10kV raster e-beam system and it gives good performance for raster scan e-beam system. In mass production, sometimes, maintaining two kinds of resist simultaneously of CAR and non-CAR are inefficient strategy to the mask house which has limited resources. This situation makes the authors to apply CAR to the 10kV raster e-beam process. Generally, the grid of 10kV raster e-beam(MEBES) is large and limited compared to the current VSB grid. Historically, many layout data is designed already based on the large limited grid and this gives to limited sizing value. Moreover, it is difficult to control exposure dose in raster e-beam system and control bias with develop time in CAR process. These situations make more difficult CAR application to raster e-beam system under the simple mask data preparation strategy. In this paper, some critical problems will be discussed in isofocal process making for raster scan e-beam system. Advantage and disadvantage will be also discussed through the comparison of basic parameters such as dose margin, develop margin, and the fogging effect between the CAR and non-CAR process in 10kV raster e-beam process.

  16. Photosensitized Chemically Amplified Resist (PSCAR) 2.0 for high-throughput and high-resolution EUV lithography: dual photosensitization of acid generation and quencher decomposition by flood exposure

    Science.gov (United States)

    Nagahara, Seiji; Carcasi, Michael; Shiraishi, Gosuke; Nakagawa, Hisashi; Dei, Satoshi; Shiozawa, Takahiro; Nafus, Kathleen; De Simone, Danilo; Vandenberghe, Geert; Stock, Hans-Jürgen; Küchler, Bernd; Hori, Masafumi; Naruoka, Takehiko; Nagai, Tomoki; Minekawa, Yukie; Iseki, Tomohiro; Kondo, Yoshihiro; Yoshihara, Kosuke; Kamei, Yuya; Tomono, Masaru; Shimada, Ryo; Biesemans, Serge; Nakashima, Hideo; Foubert, Philippe; Buitrago, Elizabeth; Vockenhuber, Michaela; Ekinci, Yasin; Oshima, Akihiro; Tagawa, Seiichi

    2017-03-01

    A new type of Photosensitized Chemically Amplified Resist (PSCAR) **: "PSCAR 2.0," is introduced in this paper. PSCAR 2.0 is composed of a protected polymer, a "photo acid generator which can be photosensitized" (PS-PAG), a "photo decomposable base (quencher) which can be photosensitized" (PS-PDB) and a photosensitizer precursor (PP). With this PSCAR 2.0, a photosensitizer (PS) is generated by an extreme ultra-violet (EUV) pattern exposure. Then, during a subsequent flood exposure, PS selectively photosensitizes the EUV exposed areas by the decomposition of a PS-PDB in addition to the decomposition of PS-PAG. As these pattern-exposed areas have the additional acid and reduced quencher concentration, the initial quencher loading in PSCAR 2.0 can be increased in order to get the same target critical dimensions (CD). The quencher loading is to be optimized simultaneously with a UV flood exposure dose to achieve the best lithographic performance and resolution. In this work, the PSCAR performance when different quenchers are used is examined by simulation and exposure experiments with the 16 nm half-pitch (HP) line/space (L/S, 1:1) patterns. According to our simulation results among resists with the different quencher types, the best performance was achieved by PSCAR 2.0 using PS-PDB with the highest possible chemical gradient resulting in the lowest line width roughness (LWR). PSCAR 2.0 performance has furthermore been confirmed on ASML's NXE:3300 with TEL's standalone pre-alpha flood exposure tool at imec. The initial PSCAR 2.0 patterning results on NXE:3300 showed the accelerated photosensitization performance with PS-PDB. From these results, we concluded that the dual sensitization of PS-PAG and PS-PDB in PSCAR 2.0 have a potential to realize a significantly improved resist performance in EUV lithography.

  17. Chemical Countermeasures for Antibiotic Resistance

    Science.gov (United States)

    2015-01-01

    New Antibacterial Discover and Development, Lucca Italy, April 15-20, 2012. • Poster: Small Molecule Suppression of Oxacillin Resistance in MRSA...1 Award Number: W81XWH-11-2-0115 TITLE: Chemical Countermeasures for Antibiotic Resistance PRINCIPAL INVESTIGATOR: Christian Melander...Countermeasures for Antibiotic Resistance 5a. CONTRACT NUMBER W81XWH-11-2-0115 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER

  18. Evaluation of the resistance to progressive collapse of monolithic reinforced concrete frame buildingswith separate amplified floors

    Directory of Open Access Journals (Sweden)

    Domarova Ekaterina Vladimirovna

    2014-02-01

    Full Text Available In the article the authors propose a simplified method of dynamic analysis of the resistance to progressive collapse of a fragment of the building bearing system with amplified floors. This method is based on representing the building bearing system as a dynamic model with a denumerable number of degrees of freedom, in which the resistance of the system is provided mainly by the behavior of the columns. The degrees of freedom number is determined by the number of floors «hanging» to amplified floors. Thecontribution of slabs in the total system resistance is not taken into account. Stress-strain state of the columns is determined by the non-linear resistance diagram, including three stages: elastic, elastic with cracks and plastic stage connected with plastic yield in the steel of the columns. The criterion of sustainability to the progressive collapse is relative strain of steel of the undestroyed columns. A numerical example of the calculation of the building resistance to progressive collapse in case of sudden destruction of one vertical element based on proposed theoretical method is offered. A model with two numbers of degrees was considered. The suggested method allows estimating the strength, deformability and stability of monolithic reinforced concrete frame buildings with separate amplified floors. In the future it is intended to complicate the model by the accounting for the influence of deformation and constructive solution of the slabs on the stiffness characteristics of the model as a system with a finite number of degrees of freedom.

  19. Rapid identification of rice blast resistance gene by specific length amplified fragment sequencing

    Directory of Open Access Journals (Sweden)

    Shen Chen

    2016-05-01

    Full Text Available Excavation of resistance genes is one of the most effective and environment-friendly measures to control the devastating rice disease caused by Magnaporthe oryzae. Many resistance genes have been mapped and characterized in the last century. Nevertheless, only a few of the total resistance genes could be really applied in the rice breeding program. Huazhan (HZ is a new native rice restorer line developed in China and widely used in hybrid rice in recent years. HZ and its crossed combinations usually show a broad spectrum of resistance against rice blast in different rice ecosystems in China. Dissection of the genetic background of HZ is very useful for its further application. In this study, a combined method based on bulked segregation analysis (BSA and specific length amplified fragment sequencing (SLAF-seq was used to identify blast resistance gene(s in HZ. A total of 56,187 SLAFs labels were captured and 9051 polymorphic SLAFs markers were analysed and procured in this study. One trait associated with candidate resistance genes region on chromosome 12 overlapping 10.2–17.6 Mb has been identified, in which 10 NBS-LRR (nucleotide-binding site-leucine-rich repeat coding genes were used as resistance gene candidates. Our result indicated that SLAF-seq with BSA is a rapid and effective method for initial identification of blast resistance genes. The identification of resistance gene in HZ will improve its molecular breeding and resistance variety application.

  20. On Demand Realization of Input and Output Resistances of MOSFET Amplifier

    Science.gov (United States)

    Singh, Meena; Roy, Sanjay; Singh, B. P.

    2011-12-01

    A novel circuit to realize both very high positive as well as negative resistances at its input and output terminals of the MOSFET amplifier is presented. The floating admittance matrix (FAM) approach is one of the neat methods of mathematical modeling of electronic devices and its uses in circuits. The zero sum property of the floating admittance matrix provides a check to the worker to proceed further or to reobserve the first equation itself. All transfer functions are represented as cofactors of the floating admittance matrix of the circuit.

  1. From chemical mixtures to antibiotic resistance.

    Science.gov (United States)

    Ye, Jun; Rensing, Christopher; Su, Jianqiang; Zhu, Yong-Guan

    2017-12-01

    In real environment, it is unlikely that contaminants exist singly; environmental contamination with chemical mixtures is a norm. However, the impacts of chemical mixtures on environmental quality and ecosystem health have been overlooked in the past. Among the complex interactions between different contaminants, their relationship with the rise of antibiotic resistance (AR) is an emerging environmental concern. In this paper, we review recent progresses on how chemicals or chemical mixtures promote AR. We propose that, through co-selection, agents causing stress to bacteria may induce AR. The mechanisms for chemical mixtures to promote AR are also discussed. We also propose that, mechanistic understanding of co-selection of chemical mixtures for AR should be a future research priority in environmental health research. Copyright © 2017. Published by Elsevier B.V.

  2. Chemical Composition, Resistant, Total Starch Content and ...

    African Journals Online (AJOL)

    This study is aimed at the potential use of cowpea starch (CS) as resistant starch in the production of noodle as a functional food and its overall acceptability. Alkaline noodle was prepared from a mixture of 100% wheat flour and varying substitution of wheat flour (2, 4% and 6%) with cowpea starch (CS). Chemical analysis ...

  3. Comparison of Power Supply Pumping of Switch-Mode Audio Power Amplifiers with Resistive Loads and Loudspeakers as Loads

    DEFF Research Database (Denmark)

    Knott, Arnold; Petersen, Lars Press

    2013-01-01

    Power supply pumping is generated by switch-mode audio power amplifiers in half-bridge configuration, when they are driving energy back into their source. This leads in most designs to a rising rail voltage and can be destructive for either the decoupling capacitors, the rectifier diodes...... waveforms and extends the model to loudspeaker loads. Measurements verify, that the amount of supply pumping is reduced by a factor of 4 when comparing the nominal resistive load to a loudspeaker. A simplified and more accurate model is proposed and the influence of supply pumping on the audio performance...... in the power supply or the power stage of the amplifier. Therefore precautions are taken by the amplifier and power supply designer to avoid those effects. Existing power supply pumping models are based on an ohmic load attached to the amplifier. This paper shows the analytical derivation of the resulting...

  4. Switched-Capacitor Filter Optimization with Respect to Switch On-State Resistance and Features of Real Operational Amplifiers

    Directory of Open Access Journals (Sweden)

    J. Hospodka

    2007-06-01

    Full Text Available The optimization of a switched-capacitor filter, which implements a biquadratic section, is described in this paper. The aim of the optimization is to obtain a required magnitude frequency response of the filter. The optimization takes into account both one of the features of real switches - their on-state resistance, and the features of real operational amplifiers - finite voltage gain and finite unity-gain bandwidth. An optimal dynamic range is to be achieved as well. The differential evolution - a kind of evolutionary algorithms - is employed for the optimization. The filter is designed by the usual way with ideal switches and ideal operational amplifiers at first. The analysis of this filter with real switches and real operational amplifiers proves that there is a significant difference between its magnitude frequency response and the one with ideal components. Hence, the optimization is applied for finding component values so that the magnitude frequency response is as similar to the one with ideal components as possible. As for other main real features of operational amplifiers - input and output resistance - it is shown that their effect is small.

  5. High temperature chemically resistant polymer concrete

    Science.gov (United States)

    Sugama, T.; Kukacka, L.E.

    High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

  6. Organization of amplified metallothionein (MT) genes in cadmium-resistant Chinese hamster cells

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrand, C.; Grady, D.; Meincke, L.; Clark, L.; Qui, X.; Fehrenbach, S.; Brown, N.; Jones, M.; Longmire, J.; Moyzis, R.

    1987-05-01

    In the parental, cadmium-sensitive, CHO cells, two MT genes (MT-I and II) have been cloned and shown to encompass approx.9 Kb of DNA. Both genes demonstrate the canonical intron-exon organization observed for other mammalian MT genes. Chromosome walking has been employed to study the organization of the MT genes in amplified cell lines. Using DNA from a highly-amplified cell line, Cd/sup r/ 200 T1, a genomic library was constructed in lambda Ch35 by standard procedures. Recombinants containing sequences complementary to a MT-II cDNA probe were isolated and characterized. Restriction enzyme analyses of these recombinants have extended the map of the MT-I and II gene region to encompass approx.35 Kb of DNA and indicate stability of the amplified genome over this region. A single SacII restriction site has been identified at the extreme 3' end of the cloned region. Since SacII is an infrequently-cutting restriction enzyme, accelerated long-range restriction mapping of the amplified MT gene region will be possible by combining chromosome walking in the MT gene region with large fragment separation using field-in-version gel electrophoresis.

  7. Low noise tuned amplifier

    Science.gov (United States)

    Kleinberg, L. L. (Inventor)

    1984-01-01

    A bandpass amplifier employing a field effect transistor amplifier first stage is described with a resistive load either a.c. or directly coupled to the non-inverting input of an operational amplifier second stage which is loaded in a Wien Bridge configuration. The bandpass amplifier may be operated with a signal injected into the gate terminal of the field effect transistor and the signal output taken from the output terminal of the operational amplifier. The operational amplifier stage appears as an inductive reactance, capacitive reactance and negative resistance at the non-inverting input of the operational amplifier, all of which appear in parallel with the resistive load of the field effect transistor.

  8. Fiber Amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten

    2017-01-01

    The chapter provides a discussion of optical fiber amplifiers and through three sections provides a detailed treatment of three types of optical fiber amplifiers, erbium doped fiber amplifiers (EDFA), Raman amplifiers, and parametric amplifiers. Each section comprises the fundamentals including...... the basic physics and relevant in-depth theoretical modeling, amplifiers characteristics and performance data as a function of specific operation parameters. Typical applications in fiber optic communication systems and the improvement achievable through the use of fiber amplifiers are illustrated....

  9. Corrosion and chemical resistant masonry materials handbook

    National Research Council Canada - National Science Library

    Sheppard, Walter Lee

    1986-01-01

    ... and other equipment. But few other than chemists and chemical engineers identify "corrosion" as chemical degradation or destruction of a material, and therefore, something that can happen to nonmetals (concrete, plastics, brick, timber, etc.) as well as to nletals. The National Association of Corrosion Engineers so defined "corrosion" over thirty years ago but this f...

  10. BI-LAYER HYBRID BIOCOMPOSITES: CHEMICAL RESISTANT AND PHYSICAL PROPERTIES

    OpenAIRE

    Mohammad Jawaid,; H. P. S. Abdul Khalil,; Azman Hassan,; Elgorban Abdallah

    2012-01-01

    Bi-layer hybrid biocomposites were fabricated by hand lay-up technique by reinforcing oil palm empty fruit bunch (EFB) and jute fibre mats with epoxy matrix. Hybrid composites were prepared by varying the relative weight fraction of the two fibres. The physical (void content, density, dimensional stability), and chemical resistant properties of hybrid composites were evaluated. When the jute fibre loading increased in hybrid composites, physical and chemical resistant properties of hybrid com...

  11. A microcontroller-based lock-in amplifier for sub-milliohm resistance measurements.

    Science.gov (United States)

    Bengtsson, Lars E

    2012-07-01

    This paper presents a novel approach to the design of a digital ohmmeter with a resolution of microcontroller and a high-impedance instrumentation amplifier only. The design uses two digital I/O-pins to alternate the current through the sample resistor and combined with a proper firmware routine, the design is a lock-in detector that discriminates any signal that is out of phase/frequency with the reference signal. This makes it possible to selectively detect the μV drop across sample resistors down to 55.6 μΩ using only the current that can be supplied by the digital output pins of a microcontroller. This is achieved without the need for an external reference signal generator and does not rely on the computing processing power of a digital signal processor.

  12. Performance of a resistive plate chamber equipped with a new prototype of amplified front-end electronics

    CERN Document Server

    Marchisone, Massimiliano

    2016-01-01

    ALICE is the LHC experiment dedicated to the study of heavy-ion collisions. At forward rapidity a muon spectrometer detects muons from low mass mesons, quarkonia, open heavy-flavor hadrons as well as weak bosons. A muon selection based on transverse momentum is made by a trigger system composed of 72 resistive plate chambers (RPCs). For the LHC Run 1 and the ongoing Run 2 the RPCs have been equipped with a non-amplified FEE called ADULT. However, in view of an increase in luminosity expected for Run 3 (2021-2023) the possibility to use an amplified FEE has been explored in order to improve the counting rate limitation and to prevent the aging of the detector, by reducing the charge per hit. A prototype of this new electronics (FEERIC) has been developed and tested first with cosmic rays before equipping one RPC in the ALICE cavern with it. In this talk the most important performance indicators - efficiency, dark current, dark rate, cluster size and total charge - of an RPC equipped with this new FEE will be r...

  13. HER2-amplified breast cancer: mechanisms of trastuzumab resistance and novel targeted therapies

    Science.gov (United States)

    Gajria, Devika; Chandarlapaty, Sarat

    2011-01-01

    HER2 amplification is seen in up to 20% of breast cancers and is associated with an aggressive phenotype. Trastuzumab, a monoclonal antibody to HER2, accrues significant clinical benefit in the metastatic and adjuvant settings. However, some patients suffer disease recurrence despite adjuvant trastuzumab therapy, and many patients with metastatic disease do not respond to therapy or develop refractory disease within 1 year of treatment. Given the increased recognition of de novo and acquired resistance to therapy, considerable research has been dedicated to understanding the molecular mechanisms of trastuzumab resistance. Here, we highlight putative models of resistance, including activation of the downstream PI3K-signaling pathway, accumulation of a constitutively active form of HER2, and crosstalk of HER2 with other growth factor receptors. The identification of these specific mechanisms of trastuzumab resistance has provided a rationale for the development of several novel HER2-targeted agents as the mechanisms have largely suggested a continued tumor dependence on HER2 signaling. We explore the emerging data for the treatment of trastuzumab-refractory disease with novel agents including lapatinib, neratinib, pertuzumab, trastuzumab-DM1, HSP90 and PI3K pathway inhibitors, and the future potential for these inhibitors which, if combined with reliable biomarkers of resistance, may ultimately usher in a new era of personalized medicine for this disease. PMID:21342044

  14. Chemically amplified negative-tone photoresist for sub-half-micron device and mask fabrication

    Science.gov (United States)

    Conley, Will; Dundatscheck, Robert; Gelorme, Jeffrey D.; Horvat, John; Martino, Ronald M.; Murphy, Elizabeth; Petrosky, Anne; Spinillo, Gary T.; Stewart, Kevin J.; Wilbarg, Robert; Wood, Robert L.

    1991-06-01

    In this paper we discuss a new alkaline soluble negative acting photoresist which incorporates a phenolic based resin, urea/formaldehyde prepolymer as a crosslinking agent and an organic acid-generating sensitizer. This system, dubbed 'EBX' (Electron Beam/X-ray) resist has demonstrated excellent lithographic properties in various exposure modes. Discussion will center on imaging characteristics in the deep and mid ultraviolet using Micrascan I and I-line (365 nm) steppers; electron-beam imaging with MEBES 10 kV mask maker and IBM's EL-4 50 kV electron beam exposure system; and XRAY imaging with point source soft x-ray and synchotron hard x-ray lithography.

  15. A single electrode voltage, current- and patch-clamp amplifier with complete stable series resistance compensation.

    Science.gov (United States)

    Strickholm, A

    1995-01-01

    An input headstage for single electrode voltage and current clamping is described which permits selecting desired operational modes during an experiment. These include cell attached or whole cell patch clamping, single micro-electrode voltage or current clamping, potential recording, iontophoresis and voltammetry. Input electrode series resistance with the electrode inserted in a cell or during whole cell patch clamping can be measured at any time. The unique circuitry allows complete compensation of the series resistance with high frequency response. The input series electrode resistance can also vary considerably around an initially set 100% compensation with intrinsic stability. An accelerator 'supercharger' or 'booster circuit' is included which can shorten the rise time of membrane potential to the command potential by a hundredfold. This improves the recording of early ion channel currents. Feedback resistors are selected remotely for the specific experimental need. Signal resolution in patch clamping is that expected from the thermal noise of the feedback resistor and electrode to membrane seal resistance. This headstage circuitry design thus allows interchangeable modes of operation and parameters during an experiment to obtain optimal conditions for signal detection and frequency response.

  16. Chemical suppressors of mlo-mediated powdery mildew resistance.

    Science.gov (United States)

    Wu, Hongpo; Kwaaitaal, Mark; Strugala, Roxana; Schaffrath, Ulrich; Bednarek, Paweł; Panstruga, Ralph

    2017-12-22

    Loss-of-function of barley mildew locus o (Mlo) confers durable broad-spectrum penetration resistance to the barley powdery mildew pathogen, Blumeria graminis f. sp. hordei (Bgh). Given the importance of mlo mutants in agriculture, surprisingly few molecular components have been identified to be required for this type of resistance in barley. With the aim to identify novel cellular factors contributing to mlo-based resistance, we devised a pharmacological inhibitor screen. Of the 41 rationally chosen compounds tested, five caused a partial suppression of mlo resistance in barley, indicated by increased levels of Bgh host cell entry. These chemicals comprise brefeldin A (BFA), 2',3'-dideoxyadenosine (DDA), 2-deoxy-d-glucose, spermidine, and 1-aminobenzotriazole. Further inhibitor analysis corroborated a key role for both anterograde and retrograde endomembrane trafficking in mlo resistance. In addition, all four ribonucleosides, some ribonucleoside derivatives, two of the five nucleobases (guanine and uracil), some guanine derivatives as well as various polyamines partially suppress mlo resistance in barley via yet unknown mechanisms. Most of the chemicals identified to be effective in partially relieving mlo resistance in barley also to some extent compromised powdery mildew resistance in an Arabidopsis mlo2 mlo6 double mutant. In summary, our study identified novel suppressors of mlo resistance that may serve as valuable probes to unravel further the molecular processes underlying this unusual type of disease resistance. © 2017 The Author(s).

  17. Metal nano-film resistivity chemical sensor.

    Science.gov (United States)

    Podešva, Pavel; Foret, František

    2016-02-01

    In this work, we present a study on reusable thin metal film resistivity-based sensor for direct measurement of binding of thiol containing molecules in liquid samples. While in bulk conductors the DC current is not influenced by the surface events to a measureable degree in a thin metal layer the electrons close to the surface conduct a significant part of electricity and are influenced by the surface interactions. In this study, the thickness of the gold layer was kept below 100 nm resulting in easily measureable resistivity changes of the metal element upon a surface SH-groups binding. No further surface modifications were necessary. Thin film gold layers deposited on a glass substrate by vacuum sputtering were photolithographically structured into four sensing elements arranged in a Wheatstone bridge to compensate for resistance fluctuations due to the temperature changes. Concentrations as low 100 pM provided measureable signals. The surface after the measurement could be electrolytically regenerated for next measurements. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Comparison of Mediterranean Pistacia lentiscus genotypes by random amplified polymorphic DNA, chemical, and morphological analyses.

    Science.gov (United States)

    Barazani, Oz; Dudai, Nativ; Golan-Goldhirsh, Avi

    2003-08-01

    Characterization of the genetic variability of Mediterranean Pistacia lentiscus genotypes by RAPD, composition of essential oils, and morphology is presented. High polymorphism in morphological parameters was found among accessions, with no significant differences in relation to geographical origin, or to gender. GC-MS analysis of leaves extracted by t-butyl methyl ether, showed 12 monoterpenes, seven sesquiterpenes, and one linear nonterpenic compound. Cluster analysis divided the accessions into two main groups according to the relative content of the major compounds, with no relation to their geographical origin. In contrast, a dendrogram based on RAPD analysis gave two main clusters according to their geographical origins. Low correlation was found between genetic and essential oil content matrices. High morphological and chemical variability on one hand, and genotypic polymorphism on the other, provide ecological advantages that might explain the distribution of Pistacia lentiscus over a wide range of habitats. The plants under study were grown together in the same climatic and environmental conditions, thus pointing to the plausible genetic basis of the observed phenotypic differences.

  19. Optimizing chemically induced resistance in tomato against Botrytis cinerea

    DEFF Research Database (Denmark)

    Luna, Estrella; Beardon, Emily G; Ravnskov, Sabine

    2016-01-01

    Resistance-inducing chemicals can offer broad-spectrum disease protection in crops, but can also affect plant growth and interactions with plant-beneficial microbes. We have evaluated different application methods of ß-aminobutyric acid (BABA) and jasmonic acid (JA) for long-lasting induced...... resistance in tomato against Botrytis cinerea. In addition, we have studied non-target effects on plant growth and root colonization by arbuscular mycorrhizal fungi (AMF). Germinating seeds for one week in BABA- or JA-containing solutions promoted seed germination efficiency, did not affect plant growth......, and induced resistance in 4 week-old plants. When formulating BABA and JA in carboxymethyl cellulose seed coating, only BABA was able to induce resistance in 4 week-old plants. Root treatment of 1 week-old seedlings with BABA or JA also induced resistance in 4 week-old plants. However, this seedling treatment...

  20. Novel gap filling BARC with high chemical resistance

    Science.gov (United States)

    Ogata, Hiroto; Hashimoto, Yuto; Usui, Yuki; Tamura, Mamoru; Ohashi, Tomoya; Sakaida, Yasushi; Kishioka, Takahiro

    2017-03-01

    In the recent of the semiconductor manufacturing process, variety of properties (narrow gap-filling and planarity etc.) are required to organic BARC in addition to the conventional requirements. Moreover, SC-1 resistance is also needed because BARC is often used as a wet etching mask when TiN processing. But conventional BARC which include crosslinker doesn't have enough SC-1 resistance, and we found that it is also difficult to obtain good gap-filling and good planarity because of outgassing and film shrinkage derived from the crosslinker. In this study, we have developed the new self-crosslinking BARC. The new crosslinking system shows low outgassing and film shrinkage because of not including crosslinker. So, novel BARC has better gap filling property and planarity and over 3 times higher SC-1 resistance than that of conventional BARC. Moreover, by adding the low molecular weight additive which has high adhesive unit to TiN surface, the novel BARC has over 10 times higher SC-1 resistance than that of conventional BARC. And this novel BARC can be applied both ArF and KrF lithography process because of broad absorbance, high etching rate, chemical resistance (SC-1, SC-2, DHF, and others) and good film thickness uniformity. In this paper, we will discuss the detail of new self-crosslinking BARC in excellent total performance and our approach to achieve high chemical resistance.

  1. Characterizing acid diffusion lengths in chemically amplified resists from measurements of deprotection kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Abhijit A. [University of Houston, Department of Chemical and Biomolecular Engineering, 4800 Calhoun Road, Houston, Texas 77204, United States; Pandey, Yogendra Narayan [University of Houston, Department of Chemical and Biomolecular Engineering, 4800 Calhoun Road, Houston, Texas 77204, United States; Doxastakis, Manolis [Institute for Molecular Engineering, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States; Stein, Gila E. [University of Houston, Department of Chemical and Biomolecular Engineering, 4800 Calhoun Road, Houston, Texas 77204, United States

    2014-10-01

    The acid-catalyzed deprotection of glassy poly(4-hydroxystyrene-co-tertbutyl acrylate) films was studied with infrared absorbance spectroscopy and stochastic simulations. Experimental data were interpreted with a simple description of subdiffusive acid transport coupled to second-order acid loss. This model predicts key attributes of observed deprotection rates, such as fast reaction at short times, slow reaction at long times, and a nonlinear dependence on acid loading. Fickian diffusion is approached by increasing the post-exposure bake temperature or adding plasticizing agents to the polymer resin. These findings demonstrate that acid mobility and overall deprotection kinetics are coupled to glassy matrix dynamics. To complement the analysis of bulk kinetics, acid diffusion lengths were calculated from the anomalous transport model and compared with nanopattern line widths. The consistent scaling between experiments and simulations suggests that the anomalous diffusion model could be further developed into a predictive lithography tool.

  2. Photomask defect tracing, analysis, and reduction with chemically amplified resist process

    Science.gov (United States)

    Lin, Cheng-ming; Lai, Rick; Huang, W. H.; Wang, B. C.; Chen, C. Y.; Kung, C. H.; Yoo, Chue-San; Chen, Jieh-Jang; Lee, Sheng-Cha

    2003-08-01

    The features of optical proximity correction are becoming very aggressive as production technology migrates into 90nm/130 nm regime. The complicated optical proximity correction (OPC) patterns often result in un-repairable defects, a major yield loss mechanisms in a mask production line. Defect control is increasingly important. A methodology for identifying defect sources and reduction is demonstrated in this paper. The mechanisms and causes of defect formation could be determined with corresponding process step on the strength of sequence inspections. The cause of half-etched opaque defect on negative CAR process was found from PR fragment contamination of e-beam exposure step. After clean-up of e-beam chamber, yield was increased over 20%. Big pinhole defect and contact of AttPSM positive process was found on ADI step. The possible cause was poor CAR adhesion. These two type defects were decreased by modification of developing recipe, special on rinse step. Design experiment with Taguchi method was used to optimize the interactive recipe of plasma descum and rinse step on developing step of implanted layer. Average defect density was decreased from 0.99 to 0.27, and percentage of zero defect rate has been increased from 29.5 to 63.3%.

  3. Anatomical and chemical characteristics associated with lodging resistance in wheat

    Directory of Open Access Journals (Sweden)

    Eryan Kong

    2013-10-01

    Full Text Available Anatomical and chemical characteristics of stems affect lodging in wheat (Triticum aestivum L. cultivars. Traits associated with lodging resistance, such as plant height, stem strength, culm wall thickness, pith diameter, and stem diameter, were extensively investigated in earlier studies. However, the solid stem trait was rarely considered. In this study, we measured a range of anatomical and chemical characteristics on solid and hollow stemmed wheat cultivars. Significant correlations were detected between resistance to lodging and several anatomical features, including width of mechanical tissue, weight of low internodes, and width of stem walls. Morphological features that gave the best indication of improved lodging resistance were increased stem width, width of mechanical tissue layer, and stem density. Multiple linear regression analysis showed that 99% of the variation in lodging resistance could be explained by the width of the mechanical tissue layer, suggesting that solid stemmed wheat has several anatomical features for increasing resistance to lodging. In addition, microsatellite markers GWM247 and GWM340 were linked to a single solid stem QTL on chromosome 3BL in a population derived from the cross Xinongshixin (solid stem/Line 3159 (hollow stem. These markers should be valuable in breeding wheat for solid stem.

  4. Human Genetic Marker for Resistance to Radiation and Chemicals

    Energy Technology Data Exchange (ETDEWEB)

    DR. Howard B. Lieberman

    2001-05-11

    TO characterize the human HRDAD9 gene and evaluate its potential as a biomarker to predict susceptibility to the deleterious health effects potentially caused by exposure to radiations or chemicals present at DOE hazardous waste cleanup sites. HRAD9 is a human gene that is highly conserved throughout evolution. Related genes have been isolated from yeasts and mice, underscoring its biological significance. Most of our previous work involved characterization of the yeast gene cognate, wherein it was determined that the corresponding protein plays a significant role in promoting resistance of cells to radiations and chemicals, and in particular, controlling cell growth in response to DNA damage.

  5. Low-Noise Band-Pass Amplifier

    Science.gov (United States)

    Kleinberg, L.

    1982-01-01

    Circuit uses standard components to overcome common limitation of JFET amplifiers. Low-noise band-pass amplifier employs JFET and operational amplifier. High gain and band-pass characteristics are achieved with suitable choice of resistances and capacitances. Circuit should find use as low-noise amplifier, for example as first stage instrumentation systems.

  6. Operational amplifiers

    CERN Document Server

    Dostal, Jiri

    1993-01-01

    This book provides the reader with the practical knowledge necessary to select and use operational amplifier devices. It presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits.Provides the reader with practical knowledge necessary to select and use operational amplifier devices. Presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits

  7. Identification of amplified fragment length polymorphism (AFLP ...

    African Journals Online (AJOL)

    Identification of amplified fragment length polymorphism (AFLP) fragments linked to soybean mosaic virus resistance gene in Glycine soja and conversion to a sequence characterized amplified regions (SCAR) marker for rapid selection.

  8. Chemical products induce resistance to Xanthomonas perforans in tomato

    Directory of Open Access Journals (Sweden)

    Adriana Terumi Itako

    2015-09-01

    Full Text Available The bacterial spot of tomato, caused by Xanthomonas spp., is a very important disease, especially in the hot and humid periods of the year. The chemical control of the disease has not been very effective for a number of reasons. This study aimed to evaluate, under greenhouse conditions, the efficacy of leaf-spraying chemicals (acibenzolar-S-methyl (ASM (0.025 g.L−1, fluazinam (0.25 g.L−1, pyraclostrobin (0.08 g.L−1, pyraclostrobin + methiran (0.02 g.L−1 + 2.2 g.L−1, copper oxychloride (1.50 g.L−1, mancozeb + copper oxychloride (0.88 g.L−1 + 0.60 g.L−1, and oxytetracycline (0.40 g.L−1 on control of bacterial spot. Tomatoes Santa Clara and Gisele cultivars were pulverized 3 days before inoculation with Xanthomonas perforans. The production of enzymes associated with resistance induction (peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, and protease was quantified from leaf samples collected 24 hours before and 24 hours after chemical spraying and at 1, 2, 4, 6, and 8 days after bacterial inoculation. All products tested controlled bacterial spot, but only ASM, pyraclostrobin, and pyraclostrobin + metiram increased the production of peroxidase in the leaves of the two tomato cultivars, and increased the production of polyphenol oxidase and β-1,3-glucanase in the Santa Clara cultivar.

  9. Chemical products induce resistance to Xanthomonas perforans in tomato.

    Science.gov (United States)

    Itako, Adriana Terumi; Tolentino Júnior, João Batista; Silva Júnior, Tadeu Antônio Fernandes da; Soman, José Marcelo; Maringoni, Antonio Carlos

    2015-01-01

    The bacterial spot of tomato, caused by Xanthomonas spp., is a very important disease, especially in the hot and humid periods of the year. The chemical control of the disease has not been very effective for a number of reasons. This study aimed to evaluate, under greenhouse conditions, the efficacy of leaf-spraying chemicals (acibenzolar-S-methyl (ASM) (0.025 g.L(-1)), fluazinam (0.25 g.L(-1)), pyraclostrobin (0.08 g.L(-1)), pyraclostrobin + methiran (0.02 g.L(-1) + 2.2 g.L(-1)), copper oxychloride (1.50 g.L(-1)), mancozeb + copper oxychloride (0.88 g.L(-1) + 0.60 g.L(-1)), and oxytetracycline (0.40 g.L(-1))) on control of bacterial spot. Tomatoes Santa Clara and Gisele cultivars were pulverized 3 days before inoculation with Xanthomonas perforans. The production of enzymes associated with resistance induction (peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, and protease) was quantified from leaf samples collected 24 hours before and 24 hours after chemical spraying and at 1, 2, 4, 6, and 8 days after bacterial inoculation. All products tested controlled bacterial spot, but only ASM, pyraclostrobin, and pyraclostrobin + metiram increased the production of peroxidase in the leaves of the two tomato cultivars, and increased the production of polyphenol oxidase and β-1,3-glucanase in the Santa Clara cultivar.

  10. Development of dominant sequence characterized amplified region (SCAR marker linked with plume moth (Exelastis atomosa Walsingham 1886 resistance in pigeon-pea

    Directory of Open Access Journals (Sweden)

    Ramya R Mishra

    2015-12-01

    Full Text Available The mode of gene action governing resistance to plume moth (Exelastis atomosa Walsingham 1886 derived from pigeon-pea (Cajanus scarabaeoides (L. Thouars accession ICPW-94 has been determined and the resistance alleles have been designated as PPM1. The progenies of F2 population and F3 families derived from an interspecific cross C. cajan (L. Huth ('ICP-26' x C. scarabaeoides (accession ICPW-94 revealed monogenic gene action for resistance to plume moth, and the dominant control by single locus or cluster of tightly linked alleles. Bulked segregant analysis (BSA of 116 F2 progenies by using 143 parental polymorphic RAPD primers could identify a fragment OPA09(910 associated with plume moth resistance in coupling phase of linkage. Further single plant analysis of the 116 F2 mapping population revealed OPA09(910 was linked to PPMi locus conferring host resistance to plume moth with recombination fraction (rf value of 0.125 (12.7 cM of Kosambi function. The resistance specific fragment OPA09(910 was cloned, sequenced and converted into a sequence characterized amplified region (SCAR marker, SCOPA09(942, which was also closely associated (10.3 cM with the locus PPMl with rf value 0.102. BLAST analysis with pigeon-pea genome sequence also confirmed its occurrence in CcLG02 (Scafseq.LG_V5.0fa and contig 01597 (AFSP01.fsa1. This SCAR marker showed reasonable screening efficiency in the F2, F3, and BC1F1 lines, thus it can be used as genetic handle in marker-assisted introgression of the genomic fragment conferring plume moth resistance and screening of breeding lines in pigeon-pea.

  11. Transcriptome Profiling and Genetic Study Reveal Amplified Carboxylesterase Genes Implicated in Temephos Resistance, in the Asian Tiger Mosquito Aedes albopictus

    Science.gov (United States)

    Grigoraki, Linda; Lagnel, Jacques; Kioulos, Ilias; Kampouraki, Anastasia; Morou, Evangelia; Labbé, Pierrick; Weill, Mylene; Vontas, John

    2015-01-01

    Background The control of Aedes albopictus, a major vector for viral diseases, such as dengue fever and chikungunya, has been largely reliant on the use of the larvicide temephos for many decades. This insecticide remains a primary control tool for several countries and it is a potential reliable reserve, for emergency epidemics or new invasion cases, in regions such as Europe which have banned its use. Resistance to temephos has been detected in some regions, but the mechanism responsible for the trait has not been investigated. Principal findings Temephos resistance was identified in an Aedes albopictus population isolated from Greece, and subsequently selected in the laboratory for a few generations. Biochemical assays suggested the association of elevated carboxylesterases (CCE), but not target site resistance (altered AChE), with this phenotype. Illumina transcriptomic analysis revealed the up-regulation of three transcripts encoding CCE genes in the temephos resistant strain. CCEae3a and CCEae6a showed the most striking up-regulation (27- and 12-folds respectively, compared to the reference susceptible strain); these genes have been previously shown to be involved in temephos resistance also in Ae. aegypti. Gene amplification was associated with elevated transcription levels of both CCEae6a and CCEae3a genes. Genetic crosses confirmed the genetic link between CCEae6a and CCEae3a amplification and temephos resistance, by demonstrating a strong association between survival to temephos exposure and gene copy numbers in the F2 generation. Other transcripts, encoding cytochrome P450s, UDP-glycosyltransferases (UGTs), cuticle and lipid biosynthesis proteins, were upregulated in resistant mosquitoes, indicating that the co-evolution of multiple mechanisms might contribute to resistance. Significance The identification of specific genes associated with insecticide resistance in Ae. albopictus for the first time is an important pre-requirement for insecticide

  12. Amplified Policymaking

    Science.gov (United States)

    Prince, Katherine; Woempner, Carolyn

    2010-01-01

    This brief examines the policy implications of two drivers of change presented in the "2020 Forecast: Creating the Future of Learning"-- Pattern Recognition and Amplified Organization. These drivers point toward a series of cultural shifts and illuminate how we are developing new ways of organizing, constructing, and managing knowledge.…

  13. Resistance to Increasing Chemical Classes of Fungicides by Virtue of "Selection by Association" in Botrytis cinerea.

    Science.gov (United States)

    Hu, Meng-Jun; Cox, Kerik D; Schnabel, Guido

    2016-12-01

    Previous research has shown that Botrytis cinerea isolates with resistance to multiple chemical classes of fungicides exist in eastern strawberry fields. In this study, the fungicide resistance profiles of 2,130 isolates from flowers of commercial strawberry fields located in multiple states was determined over four consecutive strawberry production seasons. Producers were asked to alternate single-site fungicides that were considered low risk in their specific location based on resistance monitoring results in their fields. This recommendation led to an increase of chemical class diversity used in the spray programs. Results indicated that simultaneous resistance in individual isolates to two, three, four, five, six, and seven classes of fungicides increased over time. The increase in chemical class resistances within isolates was likely due to a process we termed "selection by association", where fungicide resistance traits were often linked to the trait being selected rather than the selectable trait itself. Data analysis also indicated that the odds were highest for isolates resistant to one chemical class (1CCR) to be resistant to thiophanate-methyl; for 2CCR isolates to be resistant to thiophanate-methyl and pyraclostrobin; and for 3CCR isolates to be resistant to thiophanate-methyl, pyraclostrobin, and either cyprodinil or fenhexamid. We hypothesize that the more chemical classes are used in a spray program, the faster isolates will be selected with increasing numbers of chemical class resistances by virtue of selection by association if such isolates preexist in the population.

  14. Natural selection drives chemical resistance of Datura stramonium

    Directory of Open Access Journals (Sweden)

    Adán Miranda-Pérez

    2016-04-01

    Full Text Available Plant resistance to herbivores involves physical and chemical plant traits that prevent or diminish damage by herbivores, and hence may promote coevolutionary arm-races between interacting species. Although Datura stramonium’s concentration of tropane alkaloids is under selection by leaf beetles, it is not known whether chemical defense reduces seed predation by the specialist weevil, Trichobaris soror, and if it is evolving by natural selection. We measured infestation by T. soror as well as the concentration of the plants’ two main tropane alkaloids in 278 D. stramonium plants belonging to 31 populations in central Mexico. We assessed whether the seed predator exerted preferences on the levels of both alkaloids and whether they affect plant fitness. Results show great variation across populations in the concentration of scopolamine and atropine in both leaves and seeds of plants of D. stramonium, as well as in the intensity of infestation and the proportion of infested fruits by T. soror. The concentration of scopolamine in seeds and leaves are negatively associated across populations. We found that scopolamine concentration increases plant fitness. Our major finding was the detection of a positive relationship between the population average concentrations of scopolamine with the selection differentials of scopolamine. Such spatial variation in the direction and intensity of selection on scopolamine may represent a coevolutionary selective mosaic. Our results support the view that variation in the concentration of scopolamine among-populations of D. stramonium in central Mexico is being driven, in part, by selection exerted by T. soror, pointing an adaptive role of tropane alkaloids in this plant species.

  15. Natural selection drives chemical resistance of Datura stramonium.

    Science.gov (United States)

    Miranda-Pérez, Adán; Castillo, Guillermo; Hernández-Cumplido, Johnattan; Valverde, Pedro L; Borbolla, María; Cruz, Laura L; Tapia-López, Rosalinda; Fornoni, Juan; Flores-Ortiz, César M; Núñez-Farfán, Juan

    2016-01-01

    Plant resistance to herbivores involves physical and chemical plant traits that prevent or diminish damage by herbivores, and hence may promote coevolutionary arm-races between interacting species. Although Datura stramonium's concentration of tropane alkaloids is under selection by leaf beetles, it is not known whether chemical defense reduces seed predation by the specialist weevil, Trichobaris soror, and if it is evolving by natural selection. We measured infestation by T. soror as well as the concentration of the plants' two main tropane alkaloids in 278 D. stramonium plants belonging to 31 populations in central Mexico. We assessed whether the seed predator exerted preferences on the levels of both alkaloids and whether they affect plant fitness. Results show great variation across populations in the concentration of scopolamine and atropine in both leaves and seeds of plants of D. stramonium, as well as in the intensity of infestation and the proportion of infested fruits by T. soror. The concentration of scopolamine in seeds and leaves are negatively associated across populations. We found that scopolamine concentration increases plant fitness. Our major finding was the detection of a positive relationship between the population average concentrations of scopolamine with the selection differentials of scopolamine. Such spatial variation in the direction and intensity of selection on scopolamine may represent a coevolutionary selective mosaic. Our results support the view that variation in the concentration of scopolamine among-populations of D. stramonium in central Mexico is being driven, in part, by selection exerted by T. soror, pointing an adaptive role of tropane alkaloids in this plant species.

  16. HER2-Overexpressing Breast Cancers Amplify FGFR Signaling upon Acquisition of Resistance to Dual Therapeutic Blockade of HER2.

    Science.gov (United States)

    Hanker, Ariella B; Garrett, Joan T; Estrada, Mónica Valeria; Moore, Preston D; Ericsson, Paula González; Koch, James P; Langley, Emma; Singh, Sharat; Kim, Phillip S; Frampton, Garrett M; Sanford, Eric; Owens, Philip; Becker, Jennifer; Groseclose, M Reid; Castellino, Stephen; Joensuu, Heikki; Huober, Jens; Brase, Jan C; Majjaj, Samira; Brohée, Sylvain; Venet, David; Brown, David; Baselga, José; Piccart, Martine; Sotiriou, Christos; Arteaga, Carlos L

    2017-08-01

    Purpose: Dual blockade of HER2 with trastuzumab and lapatinib or pertuzumab has been shown to be superior to single-agent trastuzumab. However, a significant fraction of HER2-overexpressing (HER2+) breast cancers escape from these drug combinations. In this study, we sought to discover the mechanisms of acquired resistance to the combination of lapatinib + trastuzumab.Experimental Design: HER2+ BT474 xenografts were treated with lapatinib + trastuzumab long-term until resistance developed. Potential mechanisms of acquired resistance were evaluated in lapatinib + trastuzumab-resistant (LTR) tumors by targeted capture next-generation sequencing. In vitro experiments were performed to corroborate these findings, and a novel drug combination was tested against LTR xenografts. Gene expression and copy-number analyses were performed to corroborate our findings in clinical samples.Results: LTR tumors exhibited an increase in FGF3/4/19 copy number, together with an increase in FGFR phosphorylation, marked stromal changes in the tumor microenvironment, and reduced tumor uptake of lapatinib. Stimulation of BT474 cells with FGF4 promoted resistance to lapatinib + trastuzumab in vitro Treatment with FGFR tyrosine kinase inhibitors reversed these changes and overcame resistance to lapatinib + trastuzumab. High expression of FGFR1 correlated with a statistically shorter progression-free survival in patients with HER2+ early breast cancer treated with adjuvant trastuzumab. Finally, FGFR1 and/or FGF3 gene amplification correlated with a lower pathologic complete response in patients with HER2+ early breast cancer treated with neoadjuvant anti-HER2 therapy.Conclusions: Amplification of FGFR signaling promotes resistance to HER2 inhibition, which can be diminished by the combination of HER2 and FGFR inhibitors. Clin Cancer Res; 23(15); 4323-34. ©2017 AACR. ©2017 American Association for Cancer Research.

  17. Development of Chemically Amplified Optical Sensors for Continuous Blood Glucose Monitoring Final Report CRADA No. TSB-1162-95

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Stephen M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of California, Livermore, CA (United States); Mastrototaro, John J. [Minimed Technologies, Inc., Sylmar, CA (United States)

    2018-01-22

    Diabetes is a chronic disease that affects 14 million people in the U.S. and more than 110 million people worldwide. Each year in this country 27,000 diabetic patients become blind, 15,000 have kidney failure, and over 54,000 have peripheral limb amputations. In 1992, total healthcare costs in the U.S. for diabetes were more than $105 billion, approximately 15% of our healthcare budget. Conventional therapy for the most severe form of diabetes, insulin-dependent diabetes mellitus (IDDM) or Type I diabetes, is to administer one or two injections per day of various forms of insulin while monitoring blood glucose levels twice or three times daily with commercial glucometers that require blood samples. Near normal blood sugar levels (glycemic control) is difficult to achieve with conventional therapy. In the fall of 1993, the results of the 10-year $165 million Diabetes Control and Complications Trial (DCCT) were published which showed that intensive insulin management would lead to dramatically fewer cases of retinopathy (which leads to blindness), nephropathy (which leads to kidney failure), and neuropathy (which can lead to limb amputations) [New England Journal of Medicine, Vo1239, No.14 977-986 (1993)]. If existing commercial insulin pumps could be combined with a continuous glucose sensor, a more physiological and fine-tuned therapy could be provided - in effect, an artificial biomechanical pancreas would be available. Existing research suggested that such a development would dramatically improve glucose control, thus greatly reducing morbidity and mortality from this disease. MiniMed Technologies in Sylmar, CA, identified a number of optically based sensor strategies as well as candidate chemical reactions that could be used to implement a minimally invasive opto-chemical glucose sensor. LLNL evaluated these sensor strategies and chemical reactions. These evaluations were the first steps leading to development of a sensor of considerable importance that could

  18. Random amplified polymorphic DNA markers tightly linked to a gene for resistance to white pine blister rust in sugar pine

    Science.gov (United States)

    Michael E. Devey; Annette Delfino-Mix1; Bohun B. Kinloch; David B. NEALEt

    1995-01-01

    We have genetically mapped a gene for resistance to white pine blister rust (Cronartium ribicola Fisch.) in sugar pine (Pinus lambertiana Dougl.) by using an approach which relies on three factors: (i) the ability to assay for genetic markers in the haploid stage of the host's life cycle, using...

  19. Influence of Variation in Physical and Chemical Properties of Southern Red Oak Lumber on Decay Resistance

    Science.gov (United States)

    E. Richard Toole; W. N. Darwin

    1970-01-01

    Although differences in decay resistance of the heartwood of various oak species have long been recognized, the effect of changes in physical and chemical wood properties on this decay resistance have not been well defined. Scheffer et al (5) studied the decay resistance of seven native oaks. They found that, within the species of the red oak group studied, there were...

  20. Composite-Material Tanks with Chemically Resistant Liners

    Science.gov (United States)

    DeLay, Thomas K.

    2004-01-01

    Lightweight composite-material tanks with chemically resistant liners have been developed for storage of chemically reactive and/or unstable fluids . especially hydrogen peroxide. These tanks are similar, in some respects, to the ones described in gLightweight Composite-Material Tanks for Cryogenic Liquids h (MFS-31379), NASA Tech Briefs, Vol. 25, No. 1 (January, 2001), page 58; however, the present tanks are fabricated by a different procedure and they do not incorporate insulation that would be needed to prevent boil-off of cryogenic fluids. The manufacture of a tank of this type begins with the fabrication of a reusable multisegmented aluminum mandrel in the shape and size of the desired interior volume. One or more segments of the mandrel can be aluminum bosses that will be incorporated into the tank as end fittings. The mandrel is coated with a mold-release material. The mandrel is then heated to a temperature of about 400 F (approximately equal to 200 C) and coated with a thermoplastic liner material to the desired thickness [typically approxiamtely equal to 15 mils (approximately equal to 0.38 mm)] by thermal spraying. In the thermal-spraying process, the liner material in powder form is sprayed and heated to the melting temperature by a propane torch and the molten particles land on the mandrel. The sprayed liner and mandrel are allowed to cool, then the outer surface of the liner is chemically and/or mechanically etched to enhance bonding of a composite overwrap. The etched liner is wrapped with multiple layers of an epoxy resin reinforced with graphite fibers; the wrapping can be done either by manual application of epoxy-impregnated graphite cloth or by winding of epoxy-impregnated filaments. The entire assembly is heated in an autoclave to cure the epoxy. After the curing process, the multisegmented mandrel is disassembled and removed from inside, leaving the finished tank. If the tank is to be used for storing hydrogen peroxide, then the liner material

  1. Fluorescent amplified fragment length polymorphism (FAFLP genotyping demonstrates the role of biofilm-producing methicillin-resistant periocular Staphylococcus epidermidis strains in postoperative endophthalmitis

    Directory of Open Access Journals (Sweden)

    Hasnain Seyed E

    2006-01-01

    Full Text Available Abstract Background An observational case series was used to study the virulence characteristics and genotypes of paired Staphylococcus epidermidis isolates cultured from intraocular samples and from periocular environment of patients with postcataract surgery endophthalmitis. Methods Eight S. epidermidis isolates were obtained from three patients (2 from patients #1 and 2 and 4 from patient #3 whose vitreous and/or anterior chamber (AC specimens and preoperative lid/conjunctiva samples were culture positive. Cultures were identified by API-Staph phenotypic identification system and genotypically characterized by Fluorescent Amplified Fragment Length Polymorphism (FAFLP and checked for their antimicrobial susceptibility. The isolates were tested for biofilm-production and methicillin-resistance (MR by PCR amplification of icaAB and mecA gene respectively. Results Four out of eight S. epidermidis strains showed multiple drug resistance (MDR. All the eight strains were PCR positive for mecA gene whereas seven out of eight strains were positive for icaAB genes. In all three patients FAFLP typing established vitreous isolates of S. epidermidis strains to be indistinguishable from the strains isolated from the patient's conjunctival swabs. However, from patient number three there was one isolate (1030b from lid swab, which appeared to be nonpathogenic and ancestral having minor but significant differences from other three strains from the same patient. This strain also lacked icaAB gene. In silico analysis indicated possible evolution of other strains from this strain in the patient. Conclusion Methicillin-resistant biofilm positive S. epidermidis strains colonizing the conjunctiva and eyelid were responsible for postoperative endophthalmitis (POE.

  2. Influence of metakaolin on chemical resistance of concrete

    Science.gov (United States)

    Mlinárik, L.; Kopecskó, K.

    2013-12-01

    Nowadays the most suitable and widely used construction material is concrete. We could develop concrete for every request in connection with the properties of fresh concrete and the quality of hardened concrete, too. The demand is rising in application of special concretes, like high performance and ultra high performance concretes (HPC, UHPC). These are usable in extreme natural circumstances or in very corrosive surroundings (for example: sewage farm, sewer, cooling tower, biogas factories). The pH value of the commercial sewage is between 7-8, but this value is often around 4 or less. The concrete pipes, which transport the sewage, are under corrosion, because above the liquid level sulphuric acid occurs due to microbes. Acidic surroundings could start the corrosion of concrete. When the pH value reduces, the influence of the acids will increase. The most significant influence has the sulphuric acid. The pH value of sulphuric acid is about 1, or less. Earlier in the cooling towers of coal thermal power stations used special coating on the concrete wall. Recently application of high performance concrete without polymeric coating is more general. Cementitious supplementary materials are widely used to protect the concrete from these corrosive surroundings. Usually used cementitious supplementary materials are ground granulated blastfurnace slag (GGBS), flying ash (FA) or silica fume (SF). In the last years there has been a growing interest in the application of metakaolin. Metakaolin is made by heat treatment, calcinations of a natural clay mineral, kaolinite. In our present research the chemical resistance of mortars in different corrosive surroundings (pH=1 sulphuric acid; pH=3 acetic acid) and the chloride ion migration were studied on series of mortar samples using rapid chloride migration test. Cement paste and mortar samples were made with 17% metakaolin replacement or without metakaolin. The following cements were used: CEM II/A-S 42.5 N, CEM I 42.5 N-S. We

  3. Inhibitor of Apoptosis (IAP) survivin is indispensable for survival of HER2 gene-amplified breast cancer cells with primary resistance to HER1/2-targeted therapies

    Energy Technology Data Exchange (ETDEWEB)

    Oliveras-Ferraros, Cristina; Vazquez-Martin, Alejandro; Cufi, Silvia; Torres-Garcia, Violeta Zenobia [Unit of Translational Research, Catalan Institute of Oncology-Girona, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Girona Biomedical Research Institute, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Sauri-Nadal, Tamara; Barco, Sonia Del [Girona Biomedical Research Institute, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Medical Oncology, Catalan Institute of Oncology-Girona, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Lopez-Bonet, Eugeni [Girona Biomedical Research Institute, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Department of Anatomical Pathology, Dr. Josep Trueta University Hospital, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Brunet, Joan [Girona Biomedical Research Institute, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Medical Oncology, Catalan Institute of Oncology-Girona, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Martin-Castillo, Begona [Girona Biomedical Research Institute, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Unit of Clinical Research, Catalan Institute of Oncology-Girona, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Menendez, Javier A., E-mail: jmenendez@idibgi.org [Unit of Translational Research, Catalan Institute of Oncology-Girona, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain); Girona Biomedical Research Institute, Avenida de Francia S/N, E-17007 Girona, Catalonia (Spain)

    2011-04-08

    Highlights: {yields} Intrinsic trastuzumab resistance occurs in {approx}70% of metastatic HER2 + breast carcinomas (BC). {yields} Approximately 15% of early HER2 + BC relapse in spite of treatment with trastuzumab-based therapies. {yields} HER2-independent downstream pro-survival pathways might underlie trastuzumab refractoriness. {yields} Survivin is indispensable for proliferation and survival of HER2 + BC unresponsive to HER2-targeted therapies ab initio. {yields} Survivin antagonists may clinically circumvent the occurrence of de novo resistance to HER2-directed drugs. -- Abstract: Primary resistance of HER2 gene-amplified breast carcinomas (BC) to HER-targeted therapies can be explained in terms of overactive HER2-independent downstream pro-survival pathways. We here confirm that constitutive overexpression of Inhibitor of Apoptosis (IAP) survivin is indispensable for survival of HER2-positive BC cells with intrinsic cross-resistance to multiple HER1/2 inhibitors. The IC{sub 50} values for the HER1/2 Tyrosine Kinase Inhibitors (TKIs) gefitinib, erlotinib and lapatinib were up to 40-fold higher in trastuzumab-unresponsive JIMT-1 cells than in trastuzumab-naive SKBR3 cells. ELISA-based and immunoblotting assays demonstrated that trastuzumab-refractory JIMT-1 cells constitutively expressed {approx}4 times more survivin protein than trastuzumab-responsive SKBR3 cells. In response to trastuzumab, JIMT-1 cells accumulated {approx}10 times more survivin than SKBR3 cells. HER1/2 TKIs failed to down-regulate survivin expression in JIMT-1 cells whereas equimolar doses of HER1/HER2 TKIs drastically depleted survivin protein in SKBR3 cells. ELISA-based detection of histone-associated DNA fragments confirmed that trastuzumab-refractory JIMT-1 cells were intrinsically protected against the apoptotic effects of HER1/2 TKIs. Of note, when we knocked-down survivin expression using siRNA and then added trastuzumab, cell proliferation and colony formation were completely

  4. Thermally stable and chemically resistant polymer membranes : aromatic polyoxadiazoles and polytriazoles

    NARCIS (Netherlands)

    Gebben, Bert

    1988-01-01

    This thesis concerns the preparation of membranes from thermally stable and chemically resistant polymers. Two polymer families from the category of heterocyclic and aromatic polymers have been selected for investigation, the polyoxadiazoles and the polytriazoles, respectively. A major problem

  5. Propolis chemical composition and honeybee resistance against Varroa destructor.

    Science.gov (United States)

    Popova, M; Reyes, M; Le Conte, Y; Bankova, V

    2014-01-01

    Propolis is known as honeybee chemical defence against infections and parasites. Its chemical composition is variable and depends on the specificity of the local flora. However, there are no data concerning the relationship between propolis chemical composition and honeybee colony health. We tried to answer this question, studying the chemical composition of propolis of bee colonies from an apiary near Avignon, which are tolerant to Varroa destructor, comparing it with colonies from the same apiary which are non-tolerant to the mites. The results indicated that non-tolerant colonies collected more resin than the tolerant ones. The percentage of four biologically active compounds - caffeic acid and pentenyl caffeates - was higher in propolis from tolerant colonies. The results of this study pave the way to understanding the effect of propolis in individual and social immunity of the honeybees. Further studies are needed to clarify the relationship between propolis chemical composition and honeybee colony health.

  6. CURRENT ISSUES REGARDING ENDOCRINE DISRUPTING CHEMICALS AND ANTIBIOTIC RESISTANCE

    Science.gov (United States)

    Recently public concern has increased regarding industrial and environmental substances that may have adverse hormonal effects in human and wildlife populations. This concern has also been expanded to include antibiotic-resistant bacteria and the presence of various antibiotics a...

  7. Dual HER2\\PIK3CA targeting overcomes single-agent acquired resistance in HER2 amplified uterine serous carcinoma cell lines in vitro and in vivo

    Science.gov (United States)

    Lopez, Salvatore; Cocco, Emiliano; Black, Jonathan; Bellone, Stefania; Bonazzoli, Elena; Predolini, Federica; Ferrari, Francesca; Schwab, Carlton L.; English, Diana P.; Ratner, Elena; Silasi, Dan-Arin; Azodi, Masoud; Schwartz, Peter E.; Terranova, Corrado; Angioli, Roberto; Santin, Alessandro D.

    2015-01-01

    HER2/neu gene amplification and PIK3CA driver mutations are common in uterine serous carcinoma (USC), and may represent ideal therapeutic targets against this aggressive variant of endometrial cancer. We examined the sensitivity to neratinib, taselisib and the combination of the two compounds in in vitro and in vivo experiments using PIK3CA mutated and PIK3CA-wild type HER2/neu amplified USC cell lines. Cell viability and cell cycle distribution were assessed using flow-cytometry assays. Downstream signaling was assessed by immunoblotting. Preclinical efficacy of single versus dual inhibition was evaluated in vivo using two USC-xenografts. We found both single agent neratinib and taselisib to be active but only transiently effective in controlling the in vivo growth of USC xenografts harboring HER2/neu gene amplification with or without oncogenic PIK3CA mutations. In contrast, the combination of the two inhibitors caused a stronger and long lasting growth inhibition in both USC xenografts when compared to single agent therapy. Combined targeting of HER2 and PIK3CA was associated with a significant and dose-dependent increase in the percentage of cells in the G0/G1 phase of the cell cycle and a dose-dependent decline in the phosphorylation of S6. Importantly, dual inhibition therapy initiated after tumor progression in single agent-treated mice was still remarkably effective at inducing tumor regression in both large PIK3CA or pan-ErbB inhibitor-resistant USC xenografts. Dual HER2/PIK3CA blockade may represent a novel therapeutic option for USC patients harboring tumors with HER2/neu gene amplification and mutated or wild type PIK3CA resistant to chemotherapy. PMID:26333383

  8. Heat stress in chemical protective clothing: Porosity and vapour resistance

    NARCIS (Netherlands)

    Havenith, G.; Hartog, E.A. den; Martini, S.

    2011-01-01

    Heat strain in chemical protective clothing is an important factor in industrial and military practice. Various improvements to the clothing to alleviate strain while maintaining protection have been attempted. More recently, selectively permeable membranes have been introduced to improve

  9. Lincosamides: Chemical structure, biosynthesis, mechanism of action, resistance, and applications

    Czech Academy of Sciences Publication Activity Database

    Spížek, Jaroslav; Řezanka, Tomáš

    2017-01-01

    Roč. 133, June 1 SI (2017), s. 20-28 ISSN 0006-2952 Institutional support: RVO:61388971 Keywords : Lincosamides * Chemical structure * Biosynthesis and mechanism of action Subject RIV: EE - Microbiology, Virology Impact factor: 4.581, year: 2016

  10. Conversion of the random amplified polymorphic DNA (RAPD ...

    African Journals Online (AJOL)

    Conversion of the random amplified polymorphic DNA (RAPD) marker UBC#116 linked to Fusarium crown and root rot resistance gene (Frl) into a co-dominant sequence characterized amplified region (SCAR) marker for marker-assisted selection of tomato.

  11. Evolutionary and biochemical aspects of chemical stress resistance in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Thiago Motta Venancio

    2012-03-01

    Full Text Available Large-scale chemical genetics screens (chemogenomics in yeast have been widely used to find drug targets, understand the mechanism-of-action of compounds, and unravel the biochemistry of drug resistance. Chemogenomics is based on the comparison of growth of gene deletants in the presence and absence of a chemical substance. Such studies showed that more than 90% of the yeast genes are required for growth in the presence of at least one chemical. Analysis of these data, using computational approaches, has revealed non-trivial features of the natural chemical tolerance systems. As a result two non-overlapping sets of genes are seen to respectively impart robustness and evolvability in the context of natural chemical resistance. The former is composed of multidrug resistance genes, whereas the latter comprises genes sharing chemical genetic profiles with many others. Recent publications showing the potential applications chemogenomics in studying the pharmacological basis of various drugs are discussed, as well as the expansion of chemogenomics to other organisms. Finally, integration of chemogenomics with sensitive sequence analysis and ubiquitination/phosphorylation data led to the discovery of a new conserved domain and important post-translational modification pathways involved in stress resistance.

  12. Compressive Strength, Chloride Permeability, and Freeze-Thaw Resistance of MWNT Concretes under Different Chemical Treatments

    Directory of Open Access Journals (Sweden)

    Xingang Wang

    2014-01-01

    Full Text Available This study investigated compressive strength, chloride penetration, and freeze-thaw resistance of multiwalled carbon nanotube (MWNT concrete. More than 100 cylindrical specimens were used to assess test variables during sensitivity observations, including water-cement ratios (0.75, 0.5, and 0.4 and exposure to chemical agents (including gum arabic, propanol, ethanol, sodium polyacrylate, methylcellulose, sodium dodecyl sulfate, and silane. To determine the adequate sonication time for MWNT dispersal in water, the compressive strengths of MWNT concrete cylinders were measured after sonication times ranging from 2 to 24 minutes. The results demonstrated that the addition of MWNT can increase the compressive strength of concrete by up to 108%. However, without chemical treatment, MWNT concretes tend to have poor freeze-thaw resistance. Among the different chemical treatments, MWNT concrete treated with sodium polyacrylate has the best compressive strength, chloride resistance, and freeze-thaw durability.

  13. Compressive strength, chloride permeability, and freeze-thaw resistance of MWNT concretes under different chemical treatments.

    Science.gov (United States)

    Wang, Xingang; Rhee, Inkyu; Wang, Yao; Xi, Yunping

    2014-01-01

    This study investigated compressive strength, chloride penetration, and freeze-thaw resistance of multiwalled carbon nanotube (MWNT) concrete. More than 100 cylindrical specimens were used to assess test variables during sensitivity observations, including water-cement ratios (0.75, 0.5, and 0.4) and exposure to chemical agents (including gum arabic, propanol, ethanol, sodium polyacrylate, methylcellulose, sodium dodecyl sulfate, and silane). To determine the adequate sonication time for MWNT dispersal in water, the compressive strengths of MWNT concrete cylinders were measured after sonication times ranging from 2 to 24 minutes. The results demonstrated that the addition of MWNT can increase the compressive strength of concrete by up to 108%. However, without chemical treatment, MWNT concretes tend to have poor freeze-thaw resistance. Among the different chemical treatments, MWNT concrete treated with sodium polyacrylate has the best compressive strength, chloride resistance, and freeze-thaw durability.

  14. Chemical resistance/thermal and mechanical properties of unsaturated polyester-based nanocomposites

    Science.gov (United States)

    Jaya Vinse Ruban, Y.; Ginil Mon, S.; Vetha Roy, D.

    2013-01-01

    Nanocomposites were synthesized using unsaturated polyester as the matrix and organically modified montmorillonite (CA-MMT) as the reinforcing agent. XRD pattern of the modified montmorillonite showed that the interlayer spacing expanded from 1.21 to 1.9 nm, indicating intercalation. TGA and DTA show loss of organic surfactant from interlayer galleries. Glass transition temperature (T g) of these composites increased from 71 °C in the unfilled unsaturated polyester to 79 °C in the composites with 5 % organically modified montmorillonite. Chemical resistance and mechanical properties of the UP/organo-clay nanocomposites were studied. Chemical resistance was studied under aqueous conditions in acetic acid, nitric acid, hydrochloric acid, sodium hydroxide, aqueous ammonia and sodium carbonate. Chemical resistance studies reveal maximum weight gain/loss with increasing clay content. Mechanical studies show maximum characteristics for the composites-clay filled 5 % (w/w).

  15. β-Lactams: chemical structure, mode of action and mechanisms of resistance

    OpenAIRE

    Fernandes, Rúben; Amador, Paula; Prudêncio, Cristina

    2013-01-01

    This synopsis summarizes the key chemical and bacteriological characteristics of β-lactams, penicillins, cephalosporins, carbanpenems, monobactams and others. Particular notice is given to first-generation to fifth-generation cephalosporins. This review also summarizes the main resistance mechanism to antibiotics, focusing particular attention to those conferring resistance to broad-spectrum cephalosporins by means of production of emerging cephalosporinases (extended-spectrum β-lactamases an...

  16. Chemical communication of antibiotic resistance by a highly resistant subpopulation of bacterial cells.

    Directory of Open Access Journals (Sweden)

    Omar M El-Halfawy

    Full Text Available The overall antibiotic resistance of a bacterial population results from the combination of a wide range of susceptibilities displayed by subsets of bacterial cells. Bacterial heteroresistance to antibiotics has been documented for several opportunistic Gram-negative bacteria, but the mechanism of heteroresistance is unclear. We use Burkholderia cenocepacia as a model opportunistic bacterium to investigate the implications of heterogeneity in the response to the antimicrobial peptide polymyxin B (PmB and also other bactericidal antibiotics. Here, we report that B. cenocepacia is heteroresistant to PmB. Population analysis profiling also identified B. cenocepacia subpopulations arising from a seemingly homogenous culture that are resistant to higher levels of polymyxin B than the rest of the cells in the culture, and can protect the more sensitive cells from killing, as well as sensitive bacteria from other species, such as Pseudomonas aeruginosa and Escherichia coli. Communication of resistance depended on upregulation of putrescine synthesis and YceI, a widely conserved low-molecular weight secreted protein. Deletion of genes for the synthesis of putrescine and YceI abrogate protection, while pharmacologic inhibition of putrescine synthesis reduced resistance to polymyxin B. Polyamines and YceI were also required for heteroresistance of B. cenocepacia to various bactericidal antibiotics. We propose that putrescine and YceI resemble "danger" infochemicals whose increased production by a bacterial subpopulation, becoming more resistant to bactericidal antibiotics, communicates higher level of resistance to more sensitive members of the population of the same or different species.

  17. ESC resistance of commercial grade polycarbonates during exposure to butter and related chemicals

    DEFF Research Database (Denmark)

    Kjellander, Carina Koch; Nielsen, Tenna B; Ghanbari-Siahkali, Afshin

    2008-01-01

    Three commercial grades of polycarbonates (Lexan (R) 144, Lexan (R) 104 and Makrolon Rx1805) were studied with respect to resistance to environmental stress cracking (ESC) when exposed to butter and related chemicals. The polycarbonates (PCs) were extensively characterised to determine whether...

  18. Controlling the resistivity gradient in chemical vapor deposition-deposited aluminum-doped zinc oxide

    NARCIS (Netherlands)

    Ponomarev, M. V.; Verheijen, M. A.; Keuning, W.; M. C. M. van de Sanden,; Creatore, M.

    2012-01-01

    Aluminum-doped ZnO (ZnO:Al) grown by chemical vapor deposition (CVD) generally exhibit a major drawback, i.e., a gradient in resistivity extending over a large range of film thickness. The present contribution addresses the plasma-enhanced CVD deposition of ZnO: Al layers by focusing on the control

  19. Etching of wide-bandgap chemically resistant semiconductors : An electrochemical study

    NARCIS (Netherlands)

    van Dorp, D.H.|info:eu-repo/dai/nl/304837334

    2008-01-01

    The wide-bandgap semiconductors, SiC and GaN, are important for a whole range of (opto)electronic and other applications. Etching of these chemically very resistant materials poses problems in device technology. This thesis describes an electrochemical approach to etching. In addition, the use of

  20. The effect of air permeability of chemical protective clothing material on clothing vapour resistance

    NARCIS (Netherlands)

    Havenith, G.; Vuister, R.; Wammes, L.

    1996-01-01

    One of the major problems associated with Chemical Warfare Protective Clothing (CW) is the additional heat load created by the garments. For CW-overgarments, research in the direction of reducing material thickness and thus heat and vapour resistance have not resulted in major improvements. The

  1. Chemical Acidic Attack Resistance of Lightweight Concrete with Additives

    Directory of Open Access Journals (Sweden)

    Salwa H. Ahmed

    2013-04-01

    concrete by decreasing of compressive strength was less than the  effect of  HCl, while the effect of  H2SO4 on foam lightweight concrete was large and its effects was small on lightweight concrete containing SP and Limestone .The wastewater didn't shown significant effect on the weight decrease percentage due to lack of concentration of sulfates and chlorides in the wastewater, but for the loss of compressive strength, the results showed that the wastewater  does not significantly effect on the resistance of normal concrete and lightweight concrete  containing Limestone, while the effect was larger on  lightweight concrete with SP and Limestone used as fine and coarse aggregates  and on lightweight concrete with foam.

  2. The microstrip SQUID amplifier

    Science.gov (United States)

    Therrien, Roy

    .2 K. The low-loss transmission line model fits the real and imaginary parts of the microstrip input impedance very accurately. We map the low-loss transmission line model into an equivalent parallel RLC circuit in which a resistance R, inductance L, and capacitance C are calculated from the characteristic impedance and attenuation factor determined from the fits to the input impedance data. Using this equivalent RLC circuit, we model the microstrip SQUID and input network with a lumped circuit model which accurately predicts the observed gain of the amplifier. We find that gain is maximized when the input circuit is critically matched, with the imaginary part of the input impedance summing to zero and the real part equal to the 50O resistance of the coaxial input line. Thus, the full signal power is transmitted into the microstrip resonator and is dissipated in the equivalent resistance R.

  3. Amplification variable factor amplifier

    NARCIS (Netherlands)

    Akitsugu, Oshita; Nauta, Bram

    2007-01-01

    PROBLEM TO BE SOLVED: To provide an amplification factor variable amplifier capable of achieving temperature compensation of an amplification factor over a wide variable amplification factor range. ; SOLUTION: A Gilbert type amplification factor variable amplifier 11 amplifies an input signal and

  4. Amplification variable factor amplifier

    NARCIS (Netherlands)

    Akitsugu, O.; Nauta, Bram

    2006-01-01

    PROBLEM TO BE SOLVED: To provide an amplification factor variable amplifier capable of achieving temperature compensation of an amplification factor over a wide variable amplification factor range. ; SOLUTION: A Gilbert type amplification factor variable amplifier 11 amplifies an input signal and

  5. Characterization of marine bacteria highly resistant to mercury exhibiting multiple resistances to toxic chemicals

    Digital Repository Service at National Institute of Oceanography (India)

    De, J.; Ramaiah, N.

    of various heavy metals and xenobiotics were also checked. 2. Materials and methods 2.1. Bacterial isolates Mercury-resistant bacteria (MRB) in water and sediment complexes were isolated from various locations along the Indian coast during 1999...-2002 using seawater nutrient agar (SWNA: 5.0 g peptone, 1.5 g beef extract, 1.5 g yeast extract, 500 ml aged seawater, 500 ml deionised water and 15 g agar) amended with 10 ppm (? 50 ?M Hg) HgCl2 (Merck, Germany). After enumerating MRB several single...

  6. Host Resistance and Chemical Control for Management of Sclerotinia Stem Rot of Soybean in Ohio.

    Science.gov (United States)

    Huzar-Novakowiski, Jaqueline; Paul, Pierce A; Dorrance, Anne E

    2017-08-01

    Recent outbreaks of Sclerotinia stem rot (SSR) of soybean in Ohio, along with new fungicides and cultivars with resistance to this disease, have led to a renewed interest in studies to update disease management guidelines. The effect of host resistance (in moderately resistant [MR] and moderately susceptible [MS] cultivars) and chemical control on SSR and yield was evaluated in 12 environments from 2014 to 2016. The chemical treatments evaluated were an untreated check, four fungicides (boscalid, picoxystrobin, pyraclostrobin, and thiophanate-methyl), and one herbicide (lactofen) applied at soybean growth stage R1 (early flowering) alone or at R1 followed by a second application at R2 (full flowering). SSR developed in 6 of 12 environments, with mean disease incidence in the untreated check of 2.5 to 41%. The three environments with high levels of SSR (disease incidence in the untreated check >20%) were used for further statistical analysis. There were significant effects (P < 0.05) of soybean cultivar and chemical treatment on SSR levels. Significantly lower levels of SSR were observed in MR cultivars. Both boscalid and lactofen reduced SSR but did not increase yield. Pyraclostrobin increased SSR compared with the untreated check in the three environments with high levels of disease. In the six fields where SSR did not develop, chemical treatment did not increase yield, nor was the yield from the MR cultivar significantly different from the MS cultivar. For Ohio, MR cultivars alone were effective for management of SSR in soybean fields where this disease has historically occurred.

  7. Thermally stable and chemically resistant polymer membranes : aromatic polyoxadiazoles and polytriazoles

    OpenAIRE

    Gebben, Bert

    1988-01-01

    This thesis concerns the preparation of membranes from thermally stable and chemically resistant polymers. Two polymer families from the category of heterocyclic and aromatic polymers have been selected for investigation, the polyoxadiazoles and the polytriazoles, respectively. A major problem concerning these types of polymers is their bad processability due to their insolubility and infusibility. For the polyoxadiazoles this problem is circumvented by using a two-step preparation process th...

  8. Chemical Changes Associated with Increased Acid Resistance of Er:YAG Laser Irradiated Enamel

    Directory of Open Access Journals (Sweden)

    Jennifer Manuela Díaz-Monroy

    2014-01-01

    Full Text Available Background. An increase in the acid resistance of dental enamel, as well as morphological and structural changes produced by Er:YAG laser irradiation, has been reported. Purpose. To evaluate the chemical changes associated with acid resistance of enamel treated with Er:YAG laser. Methods. Forty-eight enamel samples were divided into 4 groups (n=12. Group I (control; Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm2, 200 mJ (25.5 J/cm2, and 300 mJ (38.2 J/cm2, respectively. Results. There were significant differences in composition of irradiated groups (with the exception of chlorine and in the amount of calcium released. Conclusions. Chemical changes associated with an increase in acid resistance of enamel treated with Er:YAG laser showed a clear postirradiation pattern characterized by a decrease in C at.% and an increase in O, P, and Ca at.% and no changes in Cl at.%. An increased Ca/P ratio after Er:YAG laser irradiation was associated with the use of higher laser energy densities. Chemical changes produced by acid dissolution showed a similar trend among experimental groups. Stable or increased Ca/P ratio after acid dissolution was observed in the irradiated groups, with reduction of Ca released into the acid solution.

  9. Peculiarities of Enhancing Resistant Starch in Ruminants Using Chemical Methods: Opportunities and Challenges

    Science.gov (United States)

    Deckardt, Kathrin; Khol-Parisini, Annabella; Zebeli, Qendrim

    2013-01-01

    High-producing ruminants are fed high amounts of cereal grains, at the expense of dietary fiber, to meet their high energy demands. Grains consist mainly of starch, which is easily degraded in the rumen by microbial glycosidases, providing energy for rapid growth of rumen microbes and short-chain fatty acids (SCFA) as the main energy source for the host. Yet, low dietary fiber contents and the rapid accumulation of SCFA lead to rumen disorders in cattle. The chemical processing of grains has become increasingly important to confer their starch resistances against rumen microbial glycosidases, hence generating ruminally resistant starch (RRS). In ruminants, unlike monogastric species, the strategy of enhancing resistant starch is useful, not only in lowering the amount of carbohydrate substrates available for digestion in the upper gut sections, but also in enhancing the net hepatic glucose supply, which can be utilized by the host more efficiently than the hepatic gluconeogenesis of SCFA. The use of chemical methods to enhance the RRS of grains and the feeding of RRS face challenges in the practice; therefore, the present article attempts to summarize the most important achievements in the chemical processing methods used to generate RRS, and review advantages and challenges of feeding RRS to ruminants. PMID:23736826

  10. Biochemically-resistant carbon compounds in physically- and chemically-protected soil C pools

    Science.gov (United States)

    Conant, R. T.; Haddix, M. L.; Magrini-Baer, K.; Follett, R. F.; Paul, E. A.

    2008-12-01

    Soil organic matter can be protected from decomposition through physical protection within soil aggregates, chemical protection through association with mineral particles, and biochemical stabilization through biotic or abiotic creation of decay-resistant compounds. However, the methods most often used to differentiate soil organic matter usually lead to composite fractions in which one or more of the mechanisms of protection contribute to stabilization. We developed a new approach to isolate and quantify biochemically-protected carbon within physically- and chemically-protected soil organic matter fractions. Blending physiochemical isolation of soil carbon fractions with subsequent biochemical characterization enabled us to investigate the ways that biochemical stabilization complements physical and chemical stabilization. We applied this approach for soil samples from three cultivated fields and used plant-derived shifts in 13C signatures to understand how biochemically-protected carbon contributes to overall resistance of that fraction. Results show that a variety of biochemically resistant compounds are found in all of the physical fractions isolated. Isotopic analyses indicate that these compounds are significantly older than average soil C in these fractions and that they contribute a great deal to the 14C age of these fractions.

  11. Peculiarities of Enhancing Resistant Starch in Ruminants Using Chemical Methods: Opportunities and Challenges

    Directory of Open Access Journals (Sweden)

    Qendrim Zebeli

    2013-06-01

    Full Text Available High-producing ruminants are fed high amounts of cereal grains, at the expense of dietary fiber, to meet their high energy demands. Grains consist mainly of starch, which is easily degraded in the rumen by microbial glycosidases, providing energy for rapid growth of rumen microbes and short-chain fatty acids (SCFA as the main energy source for the host. Yet, low dietary fiber contents and the rapid accumulation of SCFA lead to rumen disorders in cattle. The chemical processing of grains has become increasingly important to confer their starch resistances against rumen microbial glycosidases, hence generating ruminally resistant starch (RRS. In ruminants, unlike monogastric species, the strategy of enhancing resistant starch is useful, not only in lowering the amount of carbohydrate substrates available for digestion in the upper gut sections, but also in enhancing the net hepatic glucose supply, which can be utilized by the host more efficiently than the hepatic gluconeogenesis of SCFA. The use of chemical methods to enhance the RRS of grains and the feeding of RRS face challenges in the practice; therefore, the present article attempts to summarize the most important achievements in the chemical processing methods used to generate RRS, and review advantages and challenges of feeding RRS to ruminants

  12. Chemical Changes Associated with Increased Acid Resistance of Er:YAG Laser Irradiated Enamel

    Science.gov (United States)

    Olea-Mejía, Oscar Fernando; García-Fabila, María Magdalena; Rodríguez-Vilchis, Laura Emma; Sánchez-Flores, Ignacio; Centeno-Pedraza, Claudia

    2014-01-01

    Background. An increase in the acid resistance of dental enamel, as well as morphological and structural changes produced by Er:YAG laser irradiation, has been reported. Purpose. To evaluate the chemical changes associated with acid resistance of enamel treated with Er:YAG laser. Methods. Forty-eight enamel samples were divided into 4 groups (n = 12). Group I (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm2), 200 mJ (25.5 J/cm2), and 300 mJ (38.2 J/cm2), respectively. Results. There were significant differences in composition of irradiated groups (with the exception of chlorine) and in the amount of calcium released. Conclusions. Chemical changes associated with an increase in acid resistance of enamel treated with Er:YAG laser showed a clear postirradiation pattern characterized by a decrease in C at.% and an increase in O, P, and Ca at.% and no changes in Cl at.%. An increased Ca/P ratio after Er:YAG laser irradiation was associated with the use of higher laser energy densities. Chemical changes produced by acid dissolution showed a similar trend among experimental groups. Stable or increased Ca/P ratio after acid dissolution was observed in the irradiated groups, with reduction of Ca released into the acid solution. PMID:24600327

  13. Efficient Power Amplifier for Motor Control

    Science.gov (United States)

    Brown, R. J.

    1986-01-01

    Pulse-width-modulated amplifier supplies high current as efficiently as low current needed for starting and running motor. Key to efficiency of motor-control amplifier is V-channel metal-oxide/semiconductor transistor Q1. Device has low saturation resistance. However, has large gate input capacitance and small margin between its turn-on voltage and maximum allowable gate-to-source voltage. Circuits for output stages overcome limitations of VMOS device.

  14. Aquaporin based biomimetic membrane in forward osmosis: Chemical cleaning resistance and practical operation

    KAUST Repository

    Li, Zhenyu

    2017-07-27

    Aquaporin plays a promising role in fabricating high performance biomimetic forward osmosis (FO) membranes. However, aquaporin as a protein also has a risk of denaturation caused by various chemicals, resulting in a possible decay of membrane performance. The present study tested a novel aquaporin based biomimetic membrane in simulated membrane cleaning processes. The effects of cleaning agents on water flux and salt rejection were evaluated. The membrane showed a good resistance to the chemical agents. The water flux after chemical cleaning showed significant increases, particularly after cleaning with NaOCl and Alconox. Changes in the membrane structure and increased hydrophilicity in the surrounding areas of the aquaporin may be accountable for the increase in water permeability. The membrane shows stable salt rejection up to 99% after all cleaning agents were tested. A 15-day experiment with secondary wastewater effluent as the feed solution and seawater as the draw solution showed a stable flux and high salt rejection. The average rejection of the dissolved organic carbon from wastewater after the 15-day test was 90%. The results demonstrated that the aquaporin based biomimetic FO membrane exhibits chemical resistance for most agents used in membrane cleaning procedures, maintaining a stable flux and high salt rejection.

  15. Aquaporin based biomimetic membrane in forward osmosis: Chemical cleaning resistance and practical operation

    DEFF Research Database (Denmark)

    Li, Zhenyu; Linares, Rodrigo Valladares; Bucs, Szilard

    2017-01-01

    Aquaporin plays a promising role in fabricating high performance biomimetic forward osmosis (FO) membranes. However, aquaporin as a protein also has a risk of denaturation caused, by various chemicals, resulting in a possible decay of membrane performance. The present study tested a novel aquaporin...... based biomimetic membrane in simulated membrane cleaning processes. The effects of cleaning agents on water flux and salt rejection were evaluated. The membrane showed a good resistance to the chemical agents. The water flux after chemical cleaning showed significant increases, particularly after...... with secondary wastewater effluent as the feed solution and seawater as the draw solution showed a stable flux and high salt rejection. The average rejection of the dissolved organic carbon from wastewater after the 15-day test was 90%. The results demonstrated that the aquaporin based biomimetic FO membrane...

  16. Double conjugate laser amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, S.; Daunt, G.H.

    1991-01-29

    This paper describes a double conjugate laser amplifier system for producing a stable output laser beam in line with a laser oscillator input beam. It comprises: a laser oscillator which produces a low energy oscillator laser beam therefrom directly along a laser beam axis of the system; an amplification means comprised of double conjugate laser amplifiers further comprised of a first and a second singly phase conjugate amplifiers laterally opposite each other about the laser beam axis; polarizers with one of the polarizers positioned between each of the first and second singly phase conjugate amplifiers on the laser beam axis; Pockels cells with on of the Pockels cells positioned on the laser beam axis immediately prior to one of the polarizers; and a means for selectively switching the amplifier means comprised of applying a half-wave voltage at each of the Pockels cells to provide a polarization rotation of the input beam through 90{degrees} for routing of the oscillator laser beam directly through or reflected off the polarizes as an input beam to the amplification means wherein the amplification means amplifies the input beam twice in each of the first and second singly phase conjugate amplifiers and reflects the amplified laser beam off the polarizers as an amplified laser output beam in exactly the same direction as the input laser beam.

  17. Fitness and Competitive Ability of Botrytis cinerea Isolates with Resistance to Multiple Chemical Classes of Fungicides.

    Science.gov (United States)

    Chen, S N; Luo, C X; Hu, M J; Schnabel, G

    2016-09-01

    Resistance to multiple chemical classes of fungicides in Botrytis cinerea isolates from eastern United States strawberry fields is common and strategies to control them are needed. In this study, we compared fitness and competitive ability of eight sensitive isolates (S), eight isolates resistant to five or six chemical classes of fungicides but not to phenylpyrroles (5CCR), and eight isolates resistant to six or seven chemical classes including phenylpyrroles (6CCR/MDR1h). The latter included the MDR1h phenotype due to overexpression of atrB based on Δ497V/L in mrr1. The 6CCR/MDR1h isolates grew more slowly at 4°C on potato dextrose agar, and both 5CCR and 6CCR/MDR1h isolates were hypersensitive to osmotic stress compared with S isolates. In contrast, no differences were found in oxidative sensitivity, aggressiveness, and spore production in vivo, and sclerotia production and viability in vitro. In competition experiments, the 5CCR and 6CCR/MDR1h isolates were both outcompeted by S isolates and 6CCR/MDR1h isolates were outcompeted by 5CCR isolates in the absence of fungicide pressure. Under selective pressure of a fludioxonil/pyraclostrobin rotation, the 6CCR/MDR1h isolates dominated after coinoculation with 5CCR and S isolates. The competitive disadvantage of 5CCR and especially 6CCR/MDR1h isolates suggest that, in the absence of fungicide selection pressure, S isolates may reduce inoculum potential of multifungicide-resistant isolates under field conditions.

  18. Development of High Temperature/High Sensitivity Novel Chemical Resistive Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Chunrui [Univ. of Texas, San Antonio, TX (United States); Enriquez, Erik [Univ. of Texas, San Antonio, TX (United States); Wang, Haibing [Univ. of Texas, San Antonio, TX (United States); Xu, Xing [Univ. of Texas, San Antonio, TX (United States); Bao, Shangyong [Univ. of Texas, San Antonio, TX (United States); Collins, Gregory [Univ. of Texas, San Antonio, TX (United States)

    2013-08-13

    The research has been focused to design, fabricate, and develop high temperature/high sensitivity novel multifunctional chemical sensors for the selective detection of fossil energy gases used in power and fuel systems. By systematically studying the physical properties of the LnBaCo2O5+d (LBCO) [Ln=Pr or La] thin-films, a new concept chemical sensor based high temperature chemical resistant change has been developed for the application for the next generation highly efficient and near zero emission power generation technologies. We also discovered that the superfast chemical dynamic behavior and an ultrafast surface exchange kinetics in the highly epitaxial LBCO thin films. Furthermore, our research indicates that hydrogen can superfast diffuse in the ordered oxygen vacancy structures in the highly epitaxial LBCO thin films, which suggest that the LBCO thin film not only can be an excellent candidate for the fabrication of high temperature ultra sensitive chemical sensors and control systems for power and fuel monitoring systems, but also can be an excellent candidate for the low temperature solid oxide fuel cell anode and cathode materials.

  19. Using Quantitative Reverse Transcriptase PCR and Cell Culture Plaque Assays to Determine Resistance of Toxoplasma gondii Oocysts to Chemical Sanitizers

    Science.gov (United States)

    Toxoplasma gondii oocysts are highly resistant to many chemical sanitizers. Current methods used to determine oocyst infectivity have relied exclusively on mouse, chicken, and feline bioassays. Although considered gold standards, they only provide a qualitative assessment of oocyst infectivity. I...

  20. Physical and chemical mechanisms in oxide-based resistance random access memory.

    Science.gov (United States)

    Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Zhang, Rui; Hung, Ya-Chi; Syu, Yong-En; Chang, Yao-Feng; Chen, Min-Chen; Chu, Tian-Jian; Chen, Hsin-Lu; Pan, Chih-Hung; Shih, Chih-Cheng; Zheng, Jin-Cheng; Sze, Simon M

    2015-01-01

    In this review, we provide an overview of our work in resistive switching mechanisms on oxide-based resistance random access memory (RRAM) devices. Based on the investigation of physical and chemical mechanisms, we focus on its materials, device structures, and treatment methods so as to provide an in-depth perspective of state-of-the-art oxide-based RRAM. The critical voltage and constant reaction energy properties were found, which can be used to prospectively modulate voltage and operation time to control RRAM device working performance and forecast material composition. The quantized switching phenomena in RRAM devices were demonstrated at ultra-cryogenic temperature (4K), which is attributed to the atomic-level reaction in metallic filament. In the aspect of chemical mechanisms, we use the Coulomb Faraday theorem to investigate the chemical reaction equations of RRAM for the first time. We can clearly observe that the first-order reaction series is the basis for chemical reaction during reset process in the study. Furthermore, the activation energy of chemical reactions can be extracted by changing temperature during the reset process, from which the oxygen ion reaction process can be found in the RRAM device. As for its materials, silicon oxide is compatible to semiconductor fabrication lines. It is especially promising for the silicon oxide-doped metal technology to be introduced into the industry. Based on that, double-ended graphene oxide-doped silicon oxide based via-structure RRAM with filament self-aligning formation, and self-current limiting operation ability is demonstrated. The outstanding device characteristics are attributed to the oxidation and reduction of graphene oxide flakes formed during the sputter process. Besides, we have also adopted a new concept of supercritical CO2 fluid treatment to efficiently reduce the operation current of RRAM devices for portable electronic applications.

  1. Power amplifier circuit

    NARCIS (Netherlands)

    Takeya, Hideaki; Nauta, Bram

    2015-01-01

    PROBLEM TO BE SOLVED: To provide a power amplifier circuit which has high power efficiency while suppressing a fluctuation of output power relatively to a fluctuation of a power supply voltage in a high-efficiency switching amplifier which operates in a radio frequency band.SOLUTION: A duty ratio

  2. Oscillators and operational amplifiers

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2005-01-01

    A generalized approach to the design of oscillators using operational amplifiers as active elements is presented. A piecewise-linear model of the amplifier is used so that it make sense to investigate the eigenvalues of the Jacobian of the differential equations. The characteristic equation...

  3. Chemical resistance of core-shell particles (PS/PMMA polymerized by seeded suspension

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Belchior Ribeiro

    2017-09-01

    Full Text Available Abstract Core-shell particles were produced on seeded suspension polymerization by using polystyrene (PS as polymer core, or seed, and methyl methacrylate (MMA as the shell forming monomer. Two synthesis routes were evaluated by varying the PS seed conversion before MMA addition. The main purpose of this work was to investigate the influence of synthesis routes on the morphology and chemical resistance of the resulting particles. 1H NMR spectroscopy showed that the use of PS seeds with lower conversion led to the formation of higher amount of poly(styrene-co-MMA. The copolymer acted as a compatibilizer, decreasing the interfacial energy between both homopolymers. As a consequence, a larger amount of reduced PMMA cluster were formed, as was revealed by TEM measurements. Samples in this system showed enhanced resistance to cyclohexane attack compared with pure PS, with a PS extraction of only 37% after 54 hours test.

  4. FUNCTION OF HYDRAULIC AND CHEMICAL WATER STRESS SIGNALIZATION IN EVALUATION OF DROUGHT RESISTANCE OF JUVENILE PLANTS

    Directory of Open Access Journals (Sweden)

    K OLŠOVSKÁ

    2002-05-01

    Full Text Available In laboratory hydroponic experiments with spring barley genotypes the juvenile plants with 5 leaves were tested for their physiological responses to osmotic stress evoked by blocking the water uptake in roots by polyethylenglycol (PEG-6000 and to exogenous abscisic acid (ABA applied in the nutrient solution which inhibits the stomata opening. Results from the measurements of leaf diffusion resistance, relative water content, transpiration and leaf elongation rates show dominant role of chemical signalization drought from root environment and of stomata in the regulation of water loss as well as sensitiveness of leaf elongation to lowered water availability. Maintenance of water content and turgor in the leaf tissues resulted from expression of morphological and physiological mechanisms of resistance and tolerance to drought different from that in mature plants which might be useful in the screening genotypes with different level of drought tolerance.

  5. Influence of electropolishing and anodic oxidation on morphology, chemical composition and corrosion resistance of niobium

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Maciej; Greń, Katarzyna [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Kukharenko, Andrey I. [Institute of Metal Physics, Russian Academy of Sciences-Ural Division, S. Kovalevskoi Street 18, 620990 Yekaterinburg (Russian Federation); Ural Federal University, Mira Street 19, 620002 Yekaterinburg, Mira str. 19 (Russian Federation); Korotin, Danila M. [Institute of Metal Physics, Russian Academy of Sciences-Ural Division, S. Kovalevskoi Street 18, 620990 Yekaterinburg (Russian Federation); Michalska, Joanna [Faculty of Materials Engineering and Metallurgy, Silesian University of Technology, Krasińskiego Street 8, 40-019 Katowice (Poland); Szyk-Warszyńska, Lilianna; Mosiałek, Michał [Jerzy Haber Institute of Catalysis and Surface Chemistry PAS, Niezapominajek Street 8, 30-239 Kraków (Poland); Żak, Jerzy [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Pamuła, Elżbieta [AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Mickiewicza Avenue 30, 30-059 Kraków (Poland); Kurmaev, Ernst Z. [Institute of Metal Physics, Russian Academy of Sciences-Ural Division, S. Kovalevskoi Street 18, 620990 Yekaterinburg (Russian Federation); Cholakh, Seif O. [Ural Federal University, Mira Street 19, 620002 Yekaterinburg, Mira str. 19 (Russian Federation); Simka, Wojciech, E-mail: wojciech.simka@polsl.pl [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland)

    2014-09-01

    The work presents results of the studies performed on electropolishing of pure niobium in a bath that contained: sulphuric acid, hydrofluoric acid, ethylene glycol and acetanilide. After the electropolishing, the specimens were subjected to anodic passivation in a 1 mol dm{sup −3} phosphoric acid solution at various voltages. The surface morphology, thickness, roughness and chemical composition of the resulting oxide layers were analysed. Thusly prepared niobium samples were additionally investigated in terms of their corrosion resistance in Ringer's solution. The electropolished niobium surface was determined to be smooth and lustrous. The anodisation led to the growth of barrier-like oxide layers, which were enriched in phosphorus species. - Highlights: • Pure niobium was electropolished and subsequently anodised in a H{sub 3}PO{sub 4} solution. • Phosphorus was successfully introduced into the oxide layers after the treatment. • Corrosion resistance of niobium in Ringer's solution was improved after anodising.

  6. Inventions in the nanotechnological area considerably increase wear- and chemical resistance of construction products

    Directory of Open Access Journals (Sweden)

    VLASOV Vladimir Alexeevich

    2014-08-01

    Full Text Available The invention «Reinforced flaked element made of natural or conglomerate stone and its multilayer protective coating (RU 2520193» is referred to construction materials. Reinforced flaked element made of natural or conglomerate stone consists of: natural or conglomerate materials as the basis; multilayer coating which protects the mentioned basis from chemical substances and wearing mechanical factors influencing on this element where the multilayer coating includes at least three layers formed by one or many film-forming compositions which comprise top layer with scratch-resistant nanoparticles and encircled with polyester, melamine, phenolic, acryl or epoxy resin (or any combination of them which provides protection against scratches; damper intermediate layer made of epoxy and/or acryl resin which provides impact resistant; lower layer adjoining to the basis and containing particles of Al2O3 or silicon carbide plus acryl polymer and providing resistance to abrasive wear. Technical result is increased wear- and chemical resistance of flaked elements from natural or conglomerate materials. The invention «Fine organic suspension of carbon metal-containing nanostructures and the method to produce it (RU 2515858» is referred to the area of physical and colloid chemistry and can be used to obtain polymer compositions. Fine organic suspension of carbon metal-containing nanostructures is produced by interaction between nanostructures and polyethylenepolyamine. At first the powder of carbon metalcontaining nanostructures (which are nanoparticles of 3d-metal such as copper, cobalt, nickel stabilized in carbon nanostructures is mechanically milled, then it is mechanically ground with polyethylenepolyamine introduced portionally unless and until the content of nanostructures is less 1 g/ml. The invention results in decreased power inputs as the obtained fine organic suspension of carbon and metal-containing nanostructures is able to recover due to

  7. Fluidizable zinc titanate materials with high chemical reactivity and attrition resistance

    Science.gov (United States)

    Gupta, Raghubir P.; Gangwal, Santosh K.; Jain, Suresh C.

    1993-01-01

    Highly durable and chemically reactive zinc titanate materials are prepared in a particle size range of 50 to 400 .mu.m suitable for a fluidized-bed reactor for removing reduced sulfur species in a gaseous form by granulating a mixture of fine zinc oxide and titanium oxide with inorganic and organic binders and by optional additions of small amounts of activators such as CoO and MoO.sub.3 ; and then indurating it at 800.degree. to 900.degree. C. for a time sufficient to produce attrition-resistant granules.

  8. Aquaporin based biomimetic membrane in forward osmosis: Chemical cleaning resistance and practical operation

    DEFF Research Database (Denmark)

    Li, Zhenyu; Linares, Rodrigo Valladares; Bucs, Szilard

    2017-01-01

    based biomimetic membrane in simulated membrane cleaning processes. The effects of cleaning agents on water flux and salt rejection were evaluated. The membrane showed a good resistance to the chemical agents. The water flux after chemical cleaning showed significant increases, particularly after...... cleaning with NaOCl and Alconox. Changes in the membrane structure and increased hydrophilicity in the surrounding areas of the aquaporin may be accountable for the increase in water permeability. The membrane shows stable salt rejection up to 99% after all cleaning agents were tested. A 15-day experiment...... with secondary wastewater effluent as the feed solution and seawater as the draw solution showed a stable flux and high salt rejection. The average rejection of the dissolved organic carbon from wastewater after the 15-day test was 90%. The results demonstrated that the aquaporin based biomimetic FO membrane...

  9. Advanced Concepts in Josephson Junction Reflection Amplifiers

    Science.gov (United States)

    Lähteenmäki, Pasi; Vesterinen, Visa; Hassel, Juha; Paraoanu, G. S.; Seppä, Heikki; Hakonen, Pertti

    2014-06-01

    Low-noise amplification at microwave frequencies has become increasingly important for the research related to superconducting qubits and nanoelectromechanical systems. The fundamental limit of added noise by a phase-preserving amplifier is the standard quantum limit, often expressed as noise temperature . Towards the goal of the quantum limit, we have developed an amplifier based on intrinsic negative resistance of a selectively damped Josephson junction. Here we present measurement results on previously proposed wide-band microwave amplification and discuss the challenges for improvements on the existing designs. We have also studied flux-pumped metamaterial-based parametric amplifiers, whose operating frequency can be widely tuned by external DC-flux, and demonstrate operation at pumping, in contrast to the typical metamaterial amplifiers pumped via signal lines at.

  10. Auto-Zero Differential Amplifier

    Science.gov (United States)

    Quilligan, Gerard T. (Inventor); Aslam, Shahid (Inventor)

    2017-01-01

    An autozero amplifier may include a window comparator network to monitor an output offset of a differential amplifier. The autozero amplifier may also include an integrator to receive a signal from a latched window comparator network, and send an adjustment signal back to the differential amplifier to reduce an offset of the differential amplifier.

  11. Intrinsic and Acquired Resistance to HER2-Targeted Therapies in HER2 Gene-Amplified Breast Cancer: Mechanisms and Clinical Implications

    Science.gov (United States)

    Rexer, Brent N.; Arteaga, Carlos L.

    2012-01-01

    Approximately 25% of human breast cancers overexpress the HER2 (ErbB2) proto-oncogene, which confers a more aggressive tumor phenotype and associates with a poor prognosis in patients with this disease. Two approved therapies targeting HER2, the monoclonal antibody trastuzumab and the tyrosine kinase inhibitor lapatinib, are clinically active against this type of breast cancer. However, a significant fraction of patients with HER2+ breast cancer treated with these agents eventually relapse or develop progressive disease. This suggests that tumors acquire or possess intrinsic mechanisms of resistance that allow escape from HER2 inhibition. This review focuses on mechanisms of intrinsic and/or acquired resistance to HER2-targeted therapies that have been identified in preclinical and clinical studies. These mechanisms involve alterations to HER2 itself, coexpression or acquisition of bypass signaling through other receptor or intracellular signaling pathways, defects in mechanisms of cell cycle regulation or apoptosis, and host factors that may modulate drug response. Emerging clinical evidence already suggests that combinations of therapies targeting HER2 as well as these resistance pathways will be effective in overcoming or preventing resistance. PMID:22471661

  12. Optimization of chemical structure of Schottky-type selection diode for crossbar resistive memory.

    Science.gov (United States)

    Kim, Gun Hwan; Lee, Jong Ho; Jeon, Woojin; Song, Seul Ji; Seok, Jun Yeong; Yoon, Jung Ho; Yoon, Kyung Jean; Park, Tae Joo; Hwang, Cheol Seong

    2012-10-24

    The electrical performances of Pt/TiO(2)/Ti/Pt stacked Schottky-type diode (SD) was systematically examined, and this performance is dependent on the chemical structures of the each layer and their interfaces. The Ti layers containing a tolerable amount of oxygen showed metallic electrical conduction characteristics, which was confirmed by sheet resistance measurement with elevating the temperature, transmission line measurement (TLM), and Auger electron spectroscopy (AES) analysis. However, the chemical structure of SD stack and resulting electrical properties were crucially affected by the dissolved oxygen concentration in the Ti layers. The lower oxidation potential of the Ti layer with initially higher oxygen concentration suppressed the oxygen deficiency of the overlying TiO(2) layer induced by consumption of the oxygen from TiO(2) layer. This structure results in the lower reverse current of SDs without significant degradation of forward-state current. Conductive atomic force microscopy (CAFM) analysis showed the current conduction through the local conduction paths in the presented SDs, which guarantees a sufficient forward-current density as a selection device for highly integrated crossbar array resistive memory.

  13. Physico-chemical characterization of banana varieties resistant to black leaf streak disease for industrial purposes

    Directory of Open Access Journals (Sweden)

    Rossana Catie Bueno de Godoy

    2016-01-01

    Full Text Available ABSTRACT: Cultivated bananas have very low genetic diversity making them vulnerable to diseases such as black-Sigatoka leaf spot. However, the decision to adopt a new banana variety needs to be based on a robust evaluation of agronomical and physical-chemical characteristics. Here, we characterize new banana varieties resistant to black-Sigatoka leaf spot and compare them to the most widely used traditional variety (Grand Naine. Each variety was evaluated for a range of physic-chemical attributes associated with industrial processing and flavor: pH, TTA, TSS/TTA, total sugars, reducing sugars and non-reducing sugars, humidity, total solids and yield. The Thap Maeo variety had the highest potential as a substitute for the Grand Naine variety, having higher levels of total soluble solids, reducing sugars, total sugars and humidity. The Caipira and FHIA 2 varieties also performed well in comparison with the Grand Naine variety. Cluster analysis indicated that the Grand Naine variety was closely associated with varieties from the Gross Michel subgroup (Bucaneiro, Ambrosia and Calipso and the Caipira variety, all of which come from the same AAA genomic group. It was concluded that several of the new resistant varieties could potentially substitute the traditional variety in areas affected by black-Sigatoka leaf spot disease.

  14. Influence Of Volcanic Scoria On Mechanical Strength, Chemical Resistance And Drying Shrinkage Of Mortars

    Directory of Open Access Journals (Sweden)

    Al-Swaidani A.

    2014-09-01

    Full Text Available In the study, three types of cement have been prepared; one CEM I type (the control sample and two blended cements: CEM II/A-P and CEM II/B-P (EN 197-1, each of them with three replacement levels of volcanic scoria: (10 %, 15 %, 20 % wt. and (25 %, 30 %, 35 % wt., respectively. Strength development of mortars has been investigated at 2, 7, 28 and 90 days curing. Evaluation of chemical resistance of mortars containing scoria-based cements has been investigated through exposure to 5 % sulphate and 5 % sulphuric acid solutions in accordance with ASTM C1012 & ASTM 267, respectively. Drying shrinkage has been evaluated in accordance with ASTM C596. Test results showed that at early ages, the mortars containing CEM II/B-P binders had strengths much lower than that of the control mortar. However, at 90 days curing, the strengths were comparable to the control mortar. In addition, the increase of scoria significantly improved the sulphate resistance of mortars. Further, an increase in scoria addition improved the sulphuric acid resistance of mortar, especially at the early days of exposure. The results of drying shrinkage revealed that the CEM II/B-P mortar bars exhibited a greater contraction when compared to the control mortar, especially at early ages. However, drying shrinkage of mortars was not influenced much at longer times.

  15. Noise in Optical Amplifiers

    DEFF Research Database (Denmark)

    Jeppesen, Palle

    1997-01-01

    Noise in optical amplifiers is discussed on the basis of photons and electromagntic fields. Formulas for quantum noise from spontaneous emission, signal-spontaneous beat noise and spontaneous-spontaneous beat noise are derived.......Noise in optical amplifiers is discussed on the basis of photons and electromagntic fields. Formulas for quantum noise from spontaneous emission, signal-spontaneous beat noise and spontaneous-spontaneous beat noise are derived....

  16. Electrospun Amplified Fiber Optics

    OpenAIRE

    Morello, Giovanni; Camposeo, Andrea; Moffa, Maria; Pisignano, Dario

    2015-01-01

    A lot of research is focused on all-optical signal processing, aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for an efficient signal transmission. However, the complex fabrication methods, involving high-temperature processes performed in highly pure environment, slow down the fabrication and make amplified components expensive with respect to an ideal, ...

  17. Cryogenic ultra-low-noise SiGe transistor amplifier.

    Science.gov (United States)

    Ivanov, B I; Trgala, M; Grajcar, M; Il'ichev, E; Meyer, H-G

    2011-10-01

    An ultra-low-noise one-stage SiGe heterojunction bipolar transistor amplifier was designed for cryogenic temperatures and a frequency range of 10 kHz-100 MHz. A noise temperature T(N) ≈ 1.4 K was measured at an ambient temperature of 4.2 K at frequencies between 100 kHz and 100 MHz for a source resistance of ~50 Ω. The voltage gain of the amplifier was 25 dB at a power consumption of 720 μW. The input voltage noise spectral density of the amplifier is about 35 pV/√Hz. The low noise resistance and power consumption makes the amplifier suitable for readout of resistively shunted DC SQUID magnetometers and amplifiers.

  18. Identification and utility of sequence related amplified polymorphism ...

    African Journals Online (AJOL)

    Identification and utility of sequence related amplified polymorphism (SRAP) markers linked to bacterial wilt resistance genes in potato. ... The results show that this marker system could be used in marker assisted selection (MAS) breeding program. Keywords: Sequence related amplified polymorphism (SRAP) marker, ...

  19. Soybean root suberin: anatomical distribution, chemical composition, and relationship to partial resistance to Phytophthora sojae.

    Science.gov (United States)

    Thomas, Raymond; Fang, Xingxiao; Ranathunge, Kosala; Anderson, Terry R; Peterson, Carol A; Bernards, Mark A

    2007-05-01

    Soybean (Glycine max L. Merr.) is a versatile and important agronomic crop grown worldwide. Each year millions of dollars of potential yield revenues are lost due to a root rot disease caused by the oomycete Phytophthora sojae (Kaufmann & Gerdemann). Since the root is the primary site of infection by this organism, we undertook an examination of the physicochemical barriers in soybean root, namely, the suberized walls of the epidermis and endodermis, to establish whether or not preformed suberin (i.e. naturally present in noninfected plants) could have a role in partial resistance to P. sojae. Herein we describe the anatomical distribution and chemical composition of soybean root suberin as well as its relationship to partial resistance to P. sojae. Soybean roots contain a state I endodermis (Casparian bands only) within the first 80 mm of the root tip, and a state II endodermis (Casparian bands and some cells with suberin lamellae) in more proximal regions. A state III endodermis (with thick, cellulosic, tertiary walls) was not present within the 200-mm-long roots examined. An exodermis was also absent, but some walls of the epidermal and neighboring cortical cells were suberized. Chemically, soybean root suberin resembles a typical suberin, and consists of waxes, fatty acids, omega-hydroxy acids, alpha,omega-diacids, primary alcohols, and guaiacyl- and syringyl-substituted phenolics. Total suberin analysis of isolated soybean epidermis/outer cortex and endodermis tissues demonstrated (1) significantly higher amounts in the endodermis compared to the epidermis/outer cortex, (2) increased amounts in the endodermis as the root matured from state I to state II, (3) increased amounts in the epidermis/outer cortex along the axis of the root, and (4) significantly higher amounts in tissues isolated from a cultivar ('Conrad') with a high degree of partial resistance to P. sojae compared with a susceptible line (OX760-6). This latter correlation was extended by an

  20. Chemical insight into origin of forming-free resistive random-access memory devices

    KAUST Repository

    Wu, X.

    2011-09-29

    We demonstrate the realization of a forming-step free resistive random access memory (RRAM) device using a HfOx/TiOx/HfOx/TiOxmultilayer structure, as a replacement for the conventional HfOx-based single layer structure. High-resolution transmission electron microscopy (HRTEM), along with electron energy loss spectroscopy(EELS)analysis has been carried out to identify the distribution and the role played by Ti in the RRAM stack. Our results show that Ti out-diffusion into the HfOx layer is the chemical cause of forming-free behavior. Moreover, the capability of Ti to change its ionic state in HfOx eases the reduction-oxidation (redox) reaction, thus lead to the RRAM devices performance improvements.

  1. THE CHEMICAL AND RADIATION RESISTANCE OF POLYPHENYLENE SULFIDE AS ENCOUNTERED IN THE NUCLEAR WASTE CLEANING PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.

    2011-10-20

    Polyphenylene sulfide (PPS) is extremely resistant to gamma irradiation, caustic solution, and dilute nitric acid. PPS is the material of construction for the coalescers used in the Modular Caustic-Side Solvent Extraction Unit (MCU). After applying the equivalent of 16 years of gamma irradiation and several months of exposures to caustic solution, no dimensional changes nor chemical changes were detected in PPS whether the PPS was in fiber form or in a composite with E-glass fibers. However, PPS acts as a media for heterogeneous nucleation. In particular, PPS appears to favor aluminosilicate formation in saturated solutions of aluminum and silicon in caustic environments. Parallel testing, in progress, is examining the stability of PPS when exposed to the new solvent formulation under development for MCU. Preliminary data, after two months of exposure, PPS is remarkably stable to the new solvent.

  2. Effect of Operating Parameters and Chemical Additives on Crystal Habit and Specific Cake Resistance of Zinc Hydroxide Precipitates

    Energy Technology Data Exchange (ETDEWEB)

    Alwin, Jennifer Louise [New Mexico State Univ., Las Cruces, NM (United States)

    1999-08-01

    The effect of process parameters and chemical additives on the specific cake resistance of zinc hydroxide precipitates was investigated. The ability of a slurry to be filtered is dependent upon the particle habit of the solid and the particle habit is influenced by certain process variables. The process variables studied include neutralization temperature, agitation type, and alkalinity source used for neutralization. Several commercially available chemical additives advertised to aid in solid/liquid separation were also examined in conjunction with hydroxide precipitation. A statistical analysis revealed that the neutralization temperature and the source of alkalinity were statistically significant in influencing the specific cake resistance of zinc hydroxide precipitates in this study. The type of agitation did not significantly effect the specific cake resistance of zinc hydroxide precipitates. The use of chemical additives in conjunction with hydroxide precipitation had a favorable effect on the filterability. The morphology of the hydroxide precipitates was analyzed using scanning electron microscopy.

  3. Electrospun amplified fiber optics.

    Science.gov (United States)

    Morello, Giovanni; Camposeo, Andrea; Moffa, Maria; Pisignano, Dario

    2015-03-11

    All-optical signal processing is the focus of much research aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ∼20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm(-1)). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics.

  4. The influence of plastic deformation and chemical environment on the resistively of al-alloy overhead lines

    Directory of Open Access Journals (Sweden)

    Nowak-Woźny D.

    2005-01-01

    Full Text Available The electrical resistively and intensity of X-ray diffraction reflexes were determined for overhead line wires deformed plastically and immersed at different solutions. Immersing (chemical ageing was performed by plastic deformation along the wire axis. During chemical ageing the samples were exposed to the action of the Cl-, SO4 2-, and SO3 2- ions. Resistively was measured at room temperature and at liquid nitrogen temperature. After the X-ray and resistively measurement data were compared, it was found that three processes could take place: the flow of ions through the boundary between a sample and environment; the mechanical relaxation of vacancies near a line of dislocations, and the ordering of microstructure. These effects can lead to the anisotropy of resistively.

  5. Multiple Genetic Backgrounds of the Amplified Plasmodium falciparum Multidrug Resistance (pfmdr1) Gene and Selective Sweep of 184F Mutation in Cambodia

    Science.gov (United States)

    Vinayak, Sumiti; Alam, Md Tauqeer; Sem, Rithy; Shah, Naman K.; Susanti, Augustina I.; Lim, Pharath; Muth, Sinuon; Maguire, Jason D.; Rogers, William O.; Fandeur, Thierry; Barnwell, John W.; Escalante, Ananias A.; Wongsrichanalai, Chansuda; Ariey, Frederick; Meshnick, Steven R.; Udhayakumar, Venkatachalam

    2011-01-01

    Background The emergence of artesunate-mefloquine (AS+MQ)–resistant Plasmodium falciparum in the Thailand-Cambodia region is a major concern for malaria control. Studies indicate that copy number increase and key alleles in the pfmdr1 gene are associated with AS+MQ resistance. In the present study, we investigated evidence for a selective sweep around pfmdr1 because of the spread of adaptive mutation and/or multiple copies of this gene in the P. falciparum population in Cambodia. Methods We characterized 13 microsatellite loci flanking (± 99 kb) pfmdr1 in 93 single-clone P. falciparum infections, of which 31 had multiple copies and 62 had a single copy of the pfmdr1 gene. Results Genetic analysis revealed no difference in the mean (± standard deviation) expected heterozygosity (He) at loci around single (0.75 ± 0.03) and multiple (0.76 ± 0.04) copies of pfmdr1. Evidence of genetic hitchhiking with the selective sweep of certain haplotypes was seen around mutant (184F) pfmdr1 allele, irrespective of the copy number. There was an overall reduction of 28% in mean He (± SD) around mutant allele (0.56 ± 0.05), compared with wild-type allele (0.84 ± 0.02). Significant linkage disequilibrium was also observed between the loci flanking mutant pfmdr1 allele. Conclusion The 184F mutant allele is under selection, whereas amplification of pfmdr1 gene in this population occurs on multiple genetic backgrounds. PMID:20367478

  6. Modeling a Common-Source Amplifier Using a Ferroelectric Transistor

    Science.gov (United States)

    Sayyah, Rana; Hunt, Mitchell; MacLeond, Todd C.; Ho, Fat D.

    2010-01-01

    This paper presents a mathematical model characterizing the behavior of a common-source amplifier using a FeFET. The model is based on empirical data and incorporates several variables that affect the output, including frequency, load resistance, and gate-to-source voltage. Since the common-source amplifier is the most widely used amplifier in MOS technology, understanding and modeling the behavior of the FeFET-based common-source amplifier will help in the integration of FeFETs into many circuits.

  7. Nanoimprint lithography in the cyclic olefin copolymer, Topas, a highly ultraviolet-transparent and chemically resistant thermoplast

    DEFF Research Database (Denmark)

    Nielsen, T.; Nilsson, D.; Bundgaard, F.

    2004-01-01

    Thermal nanoimprint lithography (NIL) of the cyclic olefin copolymeric thermoplast Topas® isdemonstrated. Topas® is highly UV-transparent, has low water absorption, and is chemically resistant to hydrolysis, acids and organic polar solvents which makes it suitable for lab-on-a-chipapplications. I......Thermal nanoimprint lithography (NIL) of the cyclic olefin copolymeric thermoplast Topas® isdemonstrated. Topas® is highly UV-transparent, has low water absorption, and is chemically resistant to hydrolysis, acids and organic polar solvents which makes it suitable for lab...

  8. Optically amplifying planar glass waveguides: Laser on a chip

    DEFF Research Database (Denmark)

    Guldberg-Kjær, Søren Andreas

    The objective of this work was to devlop optically amplifying planar wavguides, using erbium-doped germano-silicate glass films deposited by PECVD (Plasma Enhanced Chemical Vapour Deposition). The waveguides should exhibit enough gain to be useful as optical amplifiers in integrated planar lightw...

  9. Chemical composition and resistance-modifying effect of the essential oil of Lantana camara Linn.

    Science.gov (United States)

    Sousa, Erlânio O; Silva, Natálya F; Rodrigues, Fabiola F G; Campos, Adriana R; Lima, Sidney G; Costa, José Galberto M

    2010-04-01

    In this work, the chemical constituents, antibacterial and modulatory activities of the essential oil of Lantana camara Linn were studied. The essential oil was extracted from the leaves of L. camara by hydrodistillation method using Clevenger's apparatus and its chemical constituents were separated and identified by GC-MS, and the relative content of each constituent was determined by area normalization. Among the 25 identified components, bicyclogermacrene (19.42%), isocaryophyllene (16.70%), valecene (12.94%) and germacrene D (12.34%) were the main constituents. The oil was examined to antibacterial and modulatory activities against the multiresistant strains of Escherichia coli and Staphylococcus aureus by microdilution test. The results show an inhibitory activity to E. coli (MIC 512 mug/ml) and S. aureus (MIC 256 mug/ml). The synergism of the essential oil and aminoglycosides was verified too, with significant reduction of MICs (7 x, 1250-5 mug/ml) against E. coli. It is suggested that the essential oil of Lantana camara Linn could be used as a source of plant-derived natural products with resistance-modifying activity.

  10. Cross-resistance Patterns to Insecticides of Several Chemical Classes Among Listronotus maculicollis (Coleoptera: Curculionidae) Populations With Different Levels of Resistance to Pyrethroids.

    Science.gov (United States)

    Kostromytska, Olga S; Wu, Shaohui; Koppenhöfer, Albrecht M

    2018-02-09

    The annual bluegrass weevil (ABW), Listronotus maculicollis Kirby (Coleoptera: Curculionidae), is the most damaging golf course insect pest in eastern North America. Heavy reliance on synthetic insecticides against this pest has led to widespread problems in controlling ABW with pyrethroid resistance already reported from populations in southern New England. This study evaluated the degree and scope of ABW resistance, determined existing cross-resistance patterns, and confirmed laboratory findings under greenhouse conditions. The susceptibility of 10 ABW populations to insecticides of different chemical classes was assessed in topical, feeding, and greenhouse assays. The level of susceptibility to pyrethroids varied significantly among populations (LD50s ranging 2.4-819.1 ng per insect for bifenthrin and 1.1-362.7 ng for λ-cyhalothrin in the topical assay). Three populations were relatively susceptible to pyrethroids, and seven populations had moderate to high resistance levels (RR50 for bifenthrin ranging 30.5-343.1). The toxicity of chlorpyrifos (RR50s ranging 3.3-15.3), spinosad (RR50s 2.4-7.7), clothianidin (RR50s 4.2-9.7), and indoxacarb (RR50s 2.8-9.7) was decreased for the pyrethroid-resistant populations. Toxicity data for bifenthrin and chlorpyrifos obtained under more realistic greenhouse conditions confirmed laboratory observations, indicating that the topical assay is an accurate method of detection and measurement of resistance level. The current study expanded the previously known geographic range of ABW pyrethroid resistance to include the New York metropolitan area, New Jersey, and eastern Pennsylvania and provided clear evidence of cross-resistance not only within the pyrethroid class but also to several other chemical classes. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. A strategy of chemical control of Apera spica-venti L. resistant to sulfonylureas traced on the molecular level

    Directory of Open Access Journals (Sweden)

    Stankiewicz-Kosyl Marta

    2017-06-01

    Full Text Available Three populations of silky bent grass (Apera spica-venti L. were tested – one that is susceptible and two that are resistant to sulfonylureas. This study assessed the efficacy of control by different herbicides in a pot experiment and estimated the molecular status of resistance to sulfonylureas in analysed populations and its effect on the efficacy of different chemical treatments. The three most effective herbicide rotation schemes were: 1 chlorsulfuron + isoproturon, ethametsulfuron + metazachlor + quinmerac, chlorsulfuron + isoproturon; 2 prosulfocarb + diflufenican, ethametsulfuron + quizalofop-p-ethyl, prosulfocarb + diflufenican; 3 diflufenican + flufenacet, quizalofop-p-ethyl, diflufenican + flufenacet. In most cases it was more difficult to destroy 100% of the resistant population from Modgarby where the majority of plants had no mutation in the als gene. In the resistant population from Babin there were significantly more individuals with mutation in the als gene, therefore exhibiting target-site resistance.

  12. Critical challenges for EUV resist materials

    Energy Technology Data Exchange (ETDEWEB)

    Naulleau, Patrick P.; Anderson, Christopher N.; Baclea-an, Lorie-Mae; Denham, Paul; George, Simi; Goldberg, Kenneth A.; Jones, Gideon; McClinton, Brittany; Miyakawa, Ryan; Rekawa, Seno; Smith, Nathan

    2011-02-28

    Although Extreme ultraviolet lithography (EUVL) is now well into the commercialization phase, critical challenges remain in the development of EUV resist materials. The major issue for the 22-nm half-pitch node remains simultaneously meeting resolution, line-edge roughness (LER), and sensitivity requirements. Although several materials have met the resolution requirements, LER and sensitivity remain a challenge. As we move beyond the 22-nm node, however, even resolution remains a significant challenge. Chemically amplified resists have yet to demonstrate the required resolution at any speed or LER for 16-nm half pitch and below. Going to non-chemically amplified resists, however, 16-nm resolution has been achieved with a LER of 2 nm but a sensitivity of only 70 mJ/cm{sup 2}.

  13. Benchmarking the state comparison amplifier

    Science.gov (United States)

    Kleczkowska, Klaudia; Puthoor, Ittoop Vergheese; Bain, Lauren; Andersson, Erika

    2017-10-01

    The state comparison amplifier is a recently proposed probabilistic quantum amplifier, intended especially for amplifying coherent states. Its realization is simple and uses only linear optics and photodetectors, and the preparation of a "guess" state, typically a coherent state. Fidelity and success probability can be high compared with other probabilistic amplifiers. State comparison amplification does, however, extract information about the amplified state, which means that it is especially important to benchmark it against a simple measure-and-resend procedure. We compare state comparison quantum amplifiers to measure-and-resend strategies, and identify parameter regimes and scenarios where these can and where they cannot provide an advantage.

  14. Enhanced performance of electrostatic precipitators through chemical modification of particle resistivity and cohesion

    Energy Technology Data Exchange (ETDEWEB)

    Durham, M.D.; Baldrey, K.E.; Bustard, C.J. [ADA Technologies, Inc., Englewood, CO (United States)

    1995-11-01

    Control of fine particles, including particulate air toxics, from utility boilers is required near-term by state and federal air regulations. Electrostatic precipitators (ESP) serve as the primary air pollution control device for the majority of coal-fired utility boilers in the Eastern and Midwestern united States. Cost-effective retrofit technologies for fine particle control, including flue gas conditioning, are needed for the large base of existing ESPs. Flue has conditioning is an attractive option because it requires minimal structural changes and lower capital costs. For flue gas conditioning to be effective for fine particle control, cohesive and particle agglomerating agents are needed to reduce reentrainment losses, since a large percentage of particulate emissions from well-performing ESPs are due to erosion, rapping, and non-rapping reentrainment. A related and somewhat ironic development is that emissions reductions of SO{sub 2} from utility boilers, as required by the Title IV acid rain program of the 1990 Clean Air Act amendments, has the potential to substantially increase particulate air toxics from existing ESPs. The switch to low-sulfur coals as an SO{sub 2} control strategy by many utilities has exacerbated ESP performance problems associated with high resistivity flyash. The use of flue gas conditioning has increased in the past several years to maintain adequate performance in ESPs which were not designed for high resistivity ash. However, commercially available flue gas conditioning systems, including NH{sub 3}/SO{sub 3} dual gas conditioning systems, have problems and inherent drawbacks which create a need for alternative conditioning agents. in particular, NH{sub 3}/SO{sub 3} systems can create odor and ash disposal problems due to ammonia outgassing. In addition, there are concerns over chemical handling safety and the potential for accidental releases.

  15. Multiple resistance of Botrytis cinerea from kiwifruit to SDHIs, QoIs and fungicides of other chemical groups.

    Science.gov (United States)

    Bardas, George A; Veloukas, Thomas; Koutita, Olga; Karaoglanidis, George S

    2010-09-01

    Botrytis cinerea Pers.: Fr. is a high-risk pathogen for fungicide resistance development that has caused resistance problems on many crops throughout the world. This study investigated the fungicide sensitivity profile of isolates from kiwifruits originating from three Greek locations with different fungicide use histories. Sensitivity was measured by in vitro fungitoxicity tests on artificial nutrient media. Seventy-six single-spore isolates were tested for sensitivity to the SDHI fungicide boscalid, the QoI pyraclostrobin, the anilinopyrimidine cyprodinil, the hydroxyanilide fenhexamid, the phenylpyrrole fludioxonil, the dicarboxamide iprodione and the benzimidazole carbendazim. All isolates from Thessaloniki showed resistance to both boscalid and pyraclostrobin, while in the other two locations the fungal population was sensitive to these two fungicides. Sensitive isolates showed EC(50) values to boscalid and pyraclostrobin ranging from 0.9 to 5.2 and from 0.04 to 0.14 mg L(-1) respectively, while the resistant isolates showed EC(50) values higher than 50 mg L(-1) for boscalid and from 16 to > 50 mg L(-1) for pyraclostrobin. All QoI-resistant isolates carried the G143A mutation in cytb. Sensitivity determinations to the remaining fungicides revealed in total eight resistance phenotypes. No isolates were resistant to the fungicides fenhexamid and fludioxonil. This is the first report of B. cinerea field isolates with resistance to both boscalid and pyraclostrobin, and it strongly suggests that there may be a major problem in controlling this important pathogen on kiwifruit. (c) 2010 Society of Chemical Industry.

  16. Chemical resistance of thin film materials based on metal oxides grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sammelselg, Väino, E-mail: vaino.sammelselg@ut.ee [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia); Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu (Estonia); Netšipailo, Ivan; Aidla, Aleks; Tarre, Aivar; Aarik, Lauri; Asari, Jelena; Ritslaid, Peeter; Aarik, Jaan [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia)

    2013-09-02

    Etching rate of technologically important metal oxide thin films in hot sulphuric acid was investigated. The films of Al-, Ti-, Cr-, and Ta-oxides studied were grown by atomic layer deposition (ALD) method on silicon substrates from different precursors in large ranges of growth temperatures (80–900 °C) in order to reveal process parameters that allow deposition of coatings with higher chemical resistance. The results obtained demonstrate that application of processes that yield films with lower concentration of residual impurities as well as crystallization of films in thermal ALD processes leads to significant decrease of etching rate. Crystalline films of materials studied showed etching rates down to values of < 5 pm/s. - Highlights: • Etching of atomic layer deposited thin metal oxide films in hot H{sub 2}SO{sub 4} was studied. • Smallest etching rates of < 5 pm/s for TiO{sub 2}, Al{sub 2}O{sub 3}, and Cr{sub 2}O{sub 3} were reached. • Highest etching rate of 2.8 nm/s for Al{sub 2}O{sub 3} was occurred. • Remarkable differences in etching of non- and crystalline films were observed.

  17. Demonstration of SQUID Parametric Amplifier.

    Science.gov (United States)

    AMPLIFIERS, *PREAMPLIFIERS, *RECEIVERS, *SUPERCONDUCTIVITY, CEPHALOPODA , ELECTROMAGNETISM, HETERODYNING, INTERFERENCE, LEVEL(QUANTITY), LIMITATIONS, MILLIMETER WAVES, NOISE, QUANTUM THEORY, RADIOFREQUENCY, SURVIVABILITY, TEMPERATURE.

  18. Highly Stable and Tunable Chemical Doping of Multilayer WS2 Field Effect Transistor: Reduction in Contact Resistance.

    Science.gov (United States)

    Khalil, Hafiz M W; Khan, Muhammad Farooq; Eom, Jonghwa; Noh, Hwayong

    2015-10-28

    The development of low resistance contacts to 2D transition-metal dichalcogenides (TMDs) is still a big challenge for the future generation field effect transistors (FETs) and optoelectronic devices. Here, we report a chemical doping technique to achieve low contact resistance by keeping the intrinsic properties of few layers WS2. The transfer length method has been used to investigate the effect of chemical doping on contact resistance. After doping, the contact resistance (Rc) of multilayer (ML) WS2 has been reduced to 0.9 kΩ·μm. The significant reduction of the Rc is mainly due to the high electron doping density, thus a reduction in Schottky barrier height, which limits the device performance. The threshold voltage of ML-WS2 FETs confirms a negative shift upon the chemical doping, as further confirmed from the positions of E(1)2g and A1g peaks in Raman spectra. The n-doped samples possess a high drain current of 65 μA/μm, with an on/off ratio of 1.05 × 10(6) and a field effect mobility of 34.7 cm(2)/(V·s) at room temperature. Furthermore, the photoelectric properties of doped WS2 flakes were also measured under deep ultraviolet light. The potential of using LiF doping in contact engineering of TMDs opens new ways to improve the device performance.

  19. Electronic amplifiers for automatic compensators

    CERN Document Server

    Polonnikov, D Ye

    1965-01-01

    Electronic Amplifiers for Automatic Compensators presents the design and operation of electronic amplifiers for use in automatic control and measuring systems. This book is composed of eight chapters that consider the problems of constructing input and output circuits of amplifiers, suppression of interference and ensuring high sensitivity.This work begins with a survey of the operating principles of electronic amplifiers in automatic compensator systems. The succeeding chapters deal with circuit selection and the calculation and determination of the principal characteristics of amplifiers, as

  20. Simplified design of IC amplifiers

    CERN Document Server

    Lenk, John

    1996-01-01

    Simplified Design of IC Amplifiers has something for everyone involved in electronics. No matter what skill level, this book shows how to design and experiment with IC amplifiers. For experimenters, students, and serious hobbyists, this book provides sufficient information to design and build IC amplifier circuits from 'scratch'. For working engineers who design amplifier circuits or select IC amplifiers, the book provides a variety of circuit configurations to make designing easier.Provides basics for all phases of practical design.Covers the most popular forms for amplif

  1. Chemical resistance of the gram-negative bacteria to different sanitizers in a water purification system

    Directory of Open Access Journals (Sweden)

    Penna Thereza CV

    2006-08-01

    Full Text Available Abstract Background Purified water for pharmaceutical purposes must be free of microbial contamination and pyrogens. Even with the additional sanitary and disinfecting treatments applied to the system (sequential operational stages, Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas alcaligenes, Pseudomonas picketti, Flavobacterium aureum, Acinetobacter lowffi and Pseudomonas diminuta were isolated and identified from a thirteen-stage purification system. To evaluate the efficacy of the chemical agents used in the disinfecting process along with those used to adjust chemical characteristics of the system, over the identified bacteria, the kinetic parameter of killing time (D-value necessary to inactivate 90% of the initial bioburden (decimal reduction time was experimentally determined. Methods Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas alcaligenes, Pseudomonas picketti, Flavobacterium aureum, Acinetobacter lowffi and Pseudomonas diminuta were called in house (wild bacteria. Pseudomonas diminuta ATCC 11568, Pseudomonas alcaligenes INCQS , Pseudomonas aeruginosa ATCC 15442, Pseudomonas fluorescens ATCC 3178, Pseudomonas picketti ATCC 5031, Bacillus subtilis ATCC 937 and Escherichia coli ATCC 25922 were used as 'standard' bacteria to evaluate resistance at 25°C against either 0.5% citric acid, 0.5% hydrochloric acid, 70% ethanol, 0.5% sodium bisulfite, 0.4% sodium hydroxide, 0.5% sodium hypochlorite, or a mixture of 2.2% hydrogen peroxide (H2O2 and 0.45% peracetic acid. Results The efficacy of the sanitizers varied with concentration and contact time to reduce decimal logarithmic (log10 population (n cycles. To kill 90% of the initial population (or one log10 cycle, the necessary time (D-value was for P. aeruginosa into: (i 0.5% citric acid, D = 3.8 min; (ii 0.5% hydrochloric acid, D = 6.9 min; (iii 70% ethanol, D = 9.7 min; (iv 0.5% sodium bisulfite, D = 5.3 min; (v 0.4% sodium hydroxide, D = 14.2 min; (vi 0.5% sodium

  2. Identification of random amplified polymorphic DNA (RAPD) marker ...

    African Journals Online (AJOL)

    ... the most effective method for disease control. The application of molecular markers is an efficient way to identify host resistance for breeding programs. In this study, bulked segregant analysis (BSA) was used to search for random amplified polymorphic DNA (RAPD) markers linked to the late blight resistance gene Ph-3, ...

  3. Building valve amplifiers

    CERN Document Server

    Jones, Morgan

    2013-01-01

    Building Valve Amplifiers is a unique hands-on guide for anyone working with tube audio equipment--as an electronics hobbyist, audiophile or audio engineer. This 2nd Edition builds on the success of the first with technology and technique revisions throughout and, significantly, a major new self-build project, worked through step-by-step, which puts into practice the principles and techniques introduced throughout the book. Particular attention has been paid to answering questions commonly asked by newcomers to the world of the valve, whether audio enthusiasts tackling their first build or

  4. Wideband amplifier design

    CERN Document Server

    Hollister, Allen L

    2007-01-01

    In this book, the theory needed to understand wideband amplifier design using the simplest models possible will be developed. This theory will be used to develop algebraic equations that describe particular circuits used in high frequency design so that the reader develops a ""gut level"" understanding of the process and circuit. SPICE and Genesys simulations will be performed to show the accuracy of the algebraic models. By looking at differences between the algebraic equations and the simulations, new algebraic models will be developed that include parameters originally left out of the model

  5. Design of a lock-amplifier circuit

    Science.gov (United States)

    Liu, H.; Huang, W. J.; Song, X.; Zhang, W. Y.; Sa, L. B.

    2017-01-01

    The lock-in amplifier is recovered by phase sensitive detection technique for the weak signal submerged in the noise background. This design is based on the TI ultra low power LM358, INA129, OPA227, OP07 and other chips as the core design and production of the lock-in amplifier. Signal generator by 10m ohms /1K ohm resistance points pressure network 10 mu V 1mV adjustable sine wave signal s (T). The concomitant interference signal together through the AC amplifier and band-pass filter signal x (T), on the other hand reference signal R (T) driven by square wave phase shift etc. steps to get the signal R (T), two signals and by phase sensitive detector are a DC full wave, again through its low pass filter and a DC amplifier to be measured signal more accurate detection, the final circuit through the AD conversion and the use of single-chip will display the output.

  6. A wideband RF amplifier for satellite tuners

    Science.gov (United States)

    Xueqing, Hu; Zheng, Gong; Yin, Shi; Foster, Dai Fa

    2011-11-01

    This paper presents the design and measured performance of a wideband amplifier for a direct conversion satellite tuner. It is composed of a wideband low noise amplifier (LNA) and a two-stage RF variable gain amplifier (VGA) with linear gain in dB and temperature compensation schemes. To meet the system linearity requirement, an improved distortion compensation technique and a bypass mode are applied on the LNA to deal with the large input signal. Wideband matching is achieved by resistive feedback and an off-chip LC-ladder matching network. A large gain control range (over 80 dB) is achieved by the VGA with process voltage and temperature compensation and dB linearization. In total, the amplifier consumes up to 26 mA current from a 3.3 V power supply. It is fabricated in a 0.35-μm SiGe BiCMOS technology and occupies a silicon area of 0.25 mm2.

  7. Contribution of salicylic acid glucosyltransferase, OsSGT1, to chemically induced disease resistance in rice plants.

    Science.gov (United States)

    Umemura, Kenji; Satou, Junji; Iwata, Michiaki; Uozumi, Nobuyuki; Koga, Jinichiro; Kawano, Tomonori; Koshiba, Tomokazu; Anzai, Hiroyuki; Mitomi, Masaaki

    2009-02-01

    Systemic acquired resistance (SAR), a natural disease response in plants, can be induced chemically. Salicylic acid (SA) acts as a key endogenous signaling molecule that mediates SAR in dicotyledonous plants. However, the role of SA in monocotyledonous plants has yet to be elucidated. In this study, the mode of action of the agrochemical protectant chemical probenazole was assessed by microarray-based determination of gene expression. Cloning and characterization of the most highly activated probenazole-responsive gene revealed that it encodes UDP-glucose:SA glucosyltransferase (OsSGT1), which catalyzes the conversion of free SA into SA O-beta-glucoside (SAG). We found that SAG accumulated in rice leaf tissue following treatment with probenazole or 2,6-dichloroisonicotinic acid. A putative OsSGT1 gene from the rice cultivar Akitakomachi was cloned and the gene product expressed in Escherichia coli was characterized, and the results suggested that probenazole-responsive OsSGT1 is involved in the production of SAG. Furthermore, RNAi-mediated silencing of the OsSGT1 gene significantly reduced the probenazole-dependent development of resistance against blast disease, further supporting the suggestion that OsSGT1 is a key mediator of development of chemically induced disease resistance. The OsSGT1 gene may contribute to the SA signaling mechanism by inducing up-regulation of SAG in rice plants.

  8. Pressure dependence of in situ boron-doped silicon films prepared by low-pressure chemical vapor deposition. II. Resistivity

    Science.gov (United States)

    Haji, L.; Hamedi, L.; Loisel, B.; Gauneau, M.; Joubert, P.; Sarret, M.

    1989-11-01

    The effects of silane pressure and temperature on the in situ boron incorporation and resistivity of low-pressure chemical vapor deposited polycrystalline silicon films were studied in the ranges of 2.5×10-3-1 Torr and 515-700 °C. By lowering the silane pressure, the boron concentration increases (up to 1×1022 cm-3) and the resistivity decreases down to about 2×10-3 Ω cm without annealing. For high deposition pressure (≥0.1 Torr), the resistivity decreases as the temperature is lowered. In this latter case the secondary-ion mass spectrometry profiles reveal a boron accumulation at the layer-substrate interface, which is always observed independently of the substrate nature.

  9. Therapeutic Strategies against Cyclin E1-Amplified Ovarian Cancers

    Science.gov (United States)

    2016-10-01

    resistance to platinum, management of CCNE1-amplified ovarian cancers is challenging. In this research, we evaluate three novel strategies against...AWARD NUMBER: W81XWH-15-1-0564 TITLE: Therapeutic Strategies against Cyclin E1-Amplified Ovarian Cancers PRINCIPAL INVESTIGATOR: Panagiotis A...Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including

  10. Arabidopsis signal transduction mutant defective in chemically and biologically induced disease resistance.

    OpenAIRE

    Delaney, T P; Friedrich, L.; Ryals, J A

    1995-01-01

    Plants possess multiple resistance mechanisms that guard against pathogen attack. Among these are inducible systems such as systemic acquired resistance (SAR). SAR is activated by pathogen exposure and leads to an increase in salicylic acid (SA), high-level expression of SAR-related genes, and resistance to a spectrum of pathogens. To identify components of the signal transduction pathways regulating SAR, a mutant screen was developed that uses 2,6-dichloroisonicotinic acid as an activator of...

  11. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  12. Etching of wide-bandgap chemically resistant semiconductors. An electrochemical study

    Energy Technology Data Exchange (ETDEWEB)

    Van Dorp, D.H.

    2008-11-19

    The wide-bandgap semiconductors, SiC and GaN, are important for a whole range of (opto)electronic and other applications. Etching of these chemically very resistant materials poses problems in device technology. This thesis describes an electrochemical approach to etching. In addition, the use of p-type SiC as a photocathode for water splitting is described. For the (photo)electrochemical dissolution of SiC two etching systems are considered: acidic fluoride and alkaline solutions. The anodic current-potential curve of SiC in KOH solution shows a typical active/passive transition. The kinetics of the dissolution reaction were elucidated and interesting applications were identified. These include defect-selective, anisotropic and material-selective etching. Anodic etching of SiC in acidic fluoride solution, as in KOH solution, occurs for the p-type semiconductor in the dark and for the n-type semiconductor under illumination. What is striking for acidic solution is the growth of a micron-thick porous silicon oxide at positive potential. Electropolishing of p-type SiC is possible, while porous etching is observed for n-type 4H and 6H-SiC under illumination. The (photo)electrochemistry of n-type epitaxial GaN in alkaline peroxy - disulphate (S2O82-) is described. The results form the basis for a consideration of the photoetching of the semiconductor. Three approaches are discussed: (1) photoanodic etching in which the potential of the semiconductor is fixed by a voltage source, (2) photogalvanic etching in which the semiconductor is short circuited to the counter electrode (no voltage source), (3) electroless photoetching (without a counter electrode). By using a two compartment cell, we showed that GaN short-circuited to a noble metal, acts as a photogalvanic cell. The factors determining the etching kinetics and surface morphology have been elucidated. It is shown that SiC is an interesting cathode for the hydrogen evolution reaction. Illuminated p-type SiC short

  13. Resistance of Type 5 chemical protective clothing against nanometric airborne particles: behaviour of seams and zipper.

    Science.gov (United States)

    Vinches, Ludwig; Hallé, Stéphane

    2017-08-21

    In the field of dermal protection, the use of chemical protective clothing (CPC) (including coveralls) are considered as the last barrier against airborne engineered nanomaterials (ENM). In the majority of cases, type 5 CPC, used against solid particles (ISO 13982-1), perform well against ENM. But in a recent study, a penetration level (PL) of up to 8.5% of polydisperse sodium chloride airborne nanoparticles has been measured. Moreover, in all the previous studies, tests were performed on a sample of protective clothing material without seams or zippers. Thus, the potential for permeation through a zipper or seams has not yet been determined, even though these areas would be privileged entry points for airborne ENM. This work was designed to evaluate the PL of airborne ENM through coveralls and specifically the PL through the seams on different parts of the CPC and the zipper. Eight current models of CPC (type 5) were selected. The samples were taken from places with and without seams and with a zipper. In some cases, a cover strip can be added to the zipper to enhance its sealing. Polydisperse nanoparticles were generated by nebulization of a sodium chloride solution. A penetration cell was developed to expose the sample to airborne nanometric particles. The NaCl particle concentration in number was measured with an ultrafine particle counter and the PL was defined as the downstream concentration divided by the upstream concentration. The results obtained show that the PL increased significantly in the presence of seams and could reach up to 90% depending on the seam's design. Moreover, this study classifies the different types of seams by their resistance against airborne ENM. As for the penetration of airborne NaCl particles through the zipper, the PL was greatly attenuated by the presence of a cover strip, but only for certain models of coveralls. Finally, the values of the pressure drop were directly linked to the type of seam. All of these conclusions provide

  14. Modeling of semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Mørk, Jesper; Bischoff, Svend; Berg, Tommy Winther

    We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed.......We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed....

  15. Biological resistance of polyethylene composites made with chemically modified fiber or flour

    Science.gov (United States)

    Rebecca E. Ibach; Craig M. Clemons

    2002-01-01

    The role of moisture in the biological decay of wood-plastic composites was investigated. Southern pine wood fiber and ponderosa pine wood flour were chemically modified using either acetic anhydride (AA), butylene oxide (BO), or propylene oxide (PO). A 50:50 mixture of high density polyethylene and either chemically modified fiber or flour, or untreated fiber or flour...

  16. Fundamentals of fiber lasers and fiber amplifiers

    CERN Document Server

    Ter-Mikirtychev, Valerii (Vartan)

    2014-01-01

    This book covers the fundamental aspects of fiber lasers and fiber amplifiers, and includes a wide range of material from laser physics fundamentals to state-of-the-art topics in this rapidly growing field of quantum electronics. Emphasis is placed on the nonlinear processes taking place in fiber lasers and amplifiers, their similarities, differences to, and their advantages over other solid-state lasers. The reader will learn basic principles of solid-state physics and optical spectroscopy of laser active centers in fibers, main operational laser regimes, and practical recommendations and suggestions on fiber laser research, laser applications, and laser product development. The book will be useful for students, researchers, and professionals who work with lasers, in the optical communications, chemical and biological industries, etc.

  17. Use of some chemical inducers to improve wheat resistance to Puccinia striiformis f. Sp. Tritici

    Directory of Open Access Journals (Sweden)

    Al-Maaroof Emad

    2014-01-01

    Full Text Available The effect of DL-β-aminobutyric acid (BABA, benzothiadiazole (BTH, indoleacetic acid (IAA and salicylic acid (SA on induced systemic resistance was investigated in moderately susceptible and susceptible wheat genotypes Tamuz-2 and AL-8/70 against Puccinia striiformis f. sp. tritici. Resistance was characterized by reduced infection of yellow rust disease (Yrd. Changes in peroxidase, phenylalanine ammonia-lyase activities and in total phenolic compound content demonstrated that the resistance to Puccinia striiformis can be induced by BABA, BTH, IAA and SA in these two wheat genotypes. Further studies are needed before a practical method using many analogue compounds, such as potassium phosphate and biotic agent for Yrd resistance in wheat is developed.

  18. Chemical probes for drug-resistance assessment by binding competition (RABC): oseltamivir susceptibility evaluation.

    Science.gov (United States)

    Cheng, Ting-Jen R; Wang, Shi-Yun; Wen, Wen-Hsien; Su, Ching-Yao; Lin, Mengi; Huang, Wen-I; Liu, Ming-Tsan; Wu, Ho-Sheng; Wang, Nung-Sen; Cheng, Chung-Kai; Chen, Chun-Lin; Ren, Chien-Tai; Wu, Chung-Yi; Fang, Jim-Min; Cheng, Yih-Shyun E; Wong, Chi-Huey

    2013-01-02

    The wizard of OS (resistance): the binding difference of neuraminidase inhibitors (zanamivir versus oseltamivir (OS)) was used to establish an assay to identify the influenza subtypes that are resistant to OS but still sensitive to zanamivir. This assay used a zanamivir-biotin conjugate to determine the OS susceptibility of a wide range of influenza viruses and over 200 clinical isolates. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Influence of aggregate type and chemical admixtures on frost resistance of lightweight mortars

    Science.gov (United States)

    Klimek, Beata; Widomski, Marcin K.; Barnat-Hunek, Danuta

    2017-07-01

    The aim of studies presented in this paper covered analyses of type of lightweight aggregate as well as aeration and hydrophobic admixtures influence on absorbability and frost resistance of heat-insulating mortars applied in the energy-efficient construction. In the presented research, expanded perlite (EP) and expanded clay aggregate (ceramsite) were used as lightweight aggregates. The measurements of the basic mechanical and physical characteristics of tested mortars were performed, including, inter alia, compressive and flexural tensile strength, density, effective (open) and total porosity, absorbability, thermal conductivity as well as frost resistance after 25 cycles of freezing and thawing. Substitution of some part of sand fraction by the lightweight aggregates, expanded clay aggregate or perlite, resulted in changes in physical properties of the tested mortars. The observed decrease in density (specific weight), coefficient of heat transport and strength parameters were simultaneously accompanied by the increase in absorbability. Researches concerning frost resistance of mortars containing ceramsite and perlite showed the improved frost resistance of mortar utilizing perlite. Most of the tested mortars shoved satisfactory frost resistance, only samples of mortar containing ceramsite and aeration admixture were destroyed. The significant influence of aerating admixture on frost resistance of mortars was determined. Hydrophobic siloxanes addition failed to adequately protect the mortars against frost erosion, regardless the type of applied aggregate.

  20. Dispersion-Engineered Traveling Wave Kinetic Inductance Parametric Amplifier

    Science.gov (United States)

    Zmuidzinas, Jonas (Inventor); Day, Peter K. (Inventor)

    2014-01-01

    A traveling wave kinetic inductance parametric amplifier comprises a superconducting transmission line and a dispersion control element. The transmission line can include periodic variations of its dimension along its length. The superconducting material can include a high normal state resistivity material. In some instances the high normal state resistivity material includes nitrogen and a metal selected from the group consisting of titanium, niobium and vanadium. The traveling wave kinetic inductance parametric amplifier is expected to exhibit a noise temperature below 100 mK/GHz.

  1. Millimeter-wave power amplifiers

    CERN Document Server

    du Preez, Jaco

    2017-01-01

    This book provides a detailed review of millimeter-wave power amplifiers, discussing design issues and performance limitations commonly encountered in light of the latest research. Power amplifiers, which are able to provide high levels of output power and linearity while being easily integrated with surrounding circuitry, are a crucial component in wireless microwave systems. The book is divided into three parts, the first of which introduces readers to mm-wave wireless systems and power amplifiers. In turn, the second focuses on design principles and EDA concepts, while the third discusses future trends in power amplifier research. The book provides essential information on mm-wave power amplifier theory, as well as the implementation options and technologies involved in their effective design, equipping researchers, circuit designers and practicing engineers to design, model, analyze, test and implement high-performance, spectrally clean and energy-efficient mm-wave systems.

  2. TEST KIT FOR FIELD EVALUATION OF THE CHEMICAL RESISTANCE OF PROTECTIVE CLOTHING

    Science.gov (United States)

    Personnel involved in emergency response and hazardous waste site activities often have the need to reach on-scene decisions regarding the effectiveness and limitations of chemical protective clothing. Three gravimetric techniques were evaluated as means for providing essential i...

  3. Surge-Resistant Nanocomposite Enameled Wire Using Silica Nanoparticles with Binary Chemical Compositions on the Surface

    OpenAIRE

    Jeseung Yoo; Yongbeom Kim; Suyong Kwon; Joohyun Lee; Young-Soo Seo

    2015-01-01

    We developed polyesterimide (PEI) nanocomposite enameled wires using surface-modified silica nanoparticles with binary chemical compositions on the surface. The modification was done using silanes assisted by ultrasound, which facilitated high density modification. Two different trimethoxysilanes were chosen for the modification on the basis of resemblance of chemical compositions on the silica surface to PEI varnish. The surface-modified silica was well dispersed in PEI varnish, which was co...

  4. Changes in the chemical structure and decay resistance of heat-treated narrow-leaved ash wood

    OpenAIRE

    Yalcin,Mesut; Ibrahim,Halil

    2015-01-01

    We analyzed the effects of heat treatment on the chemical structure of wood from narrow-leafed Ash (Fraxinus angustifolia), a fast-growing and economically valuable species. We also analyzed the effects of heat treatment on the wood’s resistance to four decay fungi. Narrow-leafed Ash wood samples were heated with saturated steam to 140, 180, 200, and 220°C for 2, 4, and 6 h. The relative contents of extractable components were analyzed, as well as the levels of holocellulose, cellulose,...

  5. Chemical mutagenesis of Gluconobacter frateurii to construct methanol-resistant mutants showing glyceric acid production from methanol-containing glycerol.

    Science.gov (United States)

    Sato, Shun; Kitamoto, Dai; Habe, Hiroshi

    2014-02-01

    To produce glyceric acid (GA) from methanol-containing glycerol, resistance to methanol of Gluconobacter frateurii NBRC103465 was improved by chemical mutagenesis using N-methyl-N'-nitro-N-nitrosoguanidine. The obtained mutant Gf398 produced 6.3 g/L GA in 5% (v/v) methanol-containing 17% (w/v) glycerol medium, in which the wild-type strain neither grew nor produced GA. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  6. A new type of functional chemical sensitizer MgH2 for improving pressure desensitization resistance of emulsion explosives

    Science.gov (United States)

    Cheng, Y. F.; Yan, S. L.; Ma, H. H.; Shen, Z. W.; Liu, R.

    2016-03-01

    In millisecond-delay blasting and deep water blasting projects, traditional emulsion explosives sensitized by the chemical sensitizer NaNO2 often encounter incomplete explosion or misfire problems because of the "pressure desensitization" phenomenon, which seriously affects blasting safety and construction progress. A MgH2-sensitized emulsion explosive was invented to solve these problems. Experimental results show that MgH2 can effectively reduce the problem of pressure desensitization. In this paper, the factors which influence the pressure desensitization of two types of emulsion explosives are studied, and resistance to this phenomenon of MgH2-sensitized emulsion explosives is discussed.

  7. The physical, chemical, and microscopic properties of masonry mortars from Alhambra Palace (Spain in reference to their earthquake resistance

    Directory of Open Access Journals (Sweden)

    Hanifi Binici

    2016-03-01

    Full Text Available Al-Andalus mortar is an ancient binding material (lime mortar that was used for centuries in numerous historical buildings in Al-Andalus, Granada (Spain. The physico-chemical and microscopic properties of Al-Andalus mortars in Granada were studied as part of an investigation into the mineral raw materials present in the territory of Spain. Scanning electron microscope and X-ray diffraction analyses of eight main types of mortars were performed to show the presence of calcite, gypsum, quartz, and muscovite minerals with organic fibers. Chemical analyses of the specimens showed that high SiO2+Al2O3+Fe2O3 contents yielded high values of hydraulicity and cementation indices. A significant result of this study was that mortars with high hydraulicity and cementation indices have high mechanical strengths. This characteristic may be the main reason for the earthquake resistance of the historical Alhambra Palace.

  8. Independent Emergence of Resistance to Seven Chemical Classes of Fungicides in Botrytis cinerea.

    Science.gov (United States)

    Fernández-Ortuño, Dolores; Grabke, Anja; Li, Xingpeng; Schnabel, Guido

    2015-04-01

    Gray mold, caused by the fungal pathogen Botrytis cinerea, is one of the most destructive diseases of small fruit crops and control is largely dependent on the application of fungicides. As part of a region-wide resistance-monitoring program that investigated 1,890 B. cinerea isolates from 189 fields in 10 states of the United States, we identified seven isolates (0.4%) from five locations in four different states with unprecedented resistance to all seven Fungicide Resistance Action Committee (FRAC) codes with single-site modes of action including FRAC 1, 2, 7, 9, 11, 12, and 17 registered in the United States for gray mold control. Resistance to thiophanate-methyl, iprodione, boscalid, pyraclostrobin, and fenhexamid was based on target gene mutations that conferred E198A and F200Y in β-tubulin, I365N/S in Bos1, H272R/Y in SdhB, G143A in Cytb, and T63I and F412S in Erg27. Isolates were grouped into MDR1 and MDR1h phenotypes based on sensitivity to fludioxonil and variations in transcription factor mrr1. MDR1h isolates had a previously described 3-bp deletion at position 497 in mrr1. Expression of ABC transporter atrB was increased in MDR1 isolates but highest in MDR1h isolates. None of the isolates with seven single resistances (SR) had identical nucleotide variations in target genes, indicating that they emerged independently. Multifungicide resistance phenotypes did not exhibit significant fitness penalties for the parameters used in this study, but MDR1h isolates produced more sclerotia at low temperatures and exhibited increased sensitivity to salt stress. In this study we show that current resistance management strategies have not been able to prevent the geographically independent development of resistance to all seven site-specific fungicides currently registered for gray mold control in the United States and document the presence of MDR1h in North America.

  9. The Influence of Chemical Surface Treatment on the Corrosion Resistance of Titanium Castings Used in Dental Prosthetics

    Directory of Open Access Journals (Sweden)

    Burnat B.

    2014-08-01

    Full Text Available Air abrasion process is used for cleaning casting surface of prosthetic components, and to prepare the surface of these elements for the application of veneering items. Its side effect, however, is that abrasive particles are embedded in the treated surface, which can be up to 30% of the surface and it constitutes the side effect of this procedure. Such a significant participation of foreign material can not be indifferent to the properties of the surface. Embedded particles can be the place of stress concentration causing cracking of ceramics, and may deteriorate corrosion resistance by forming corrosive microlinks. In the latter cases, it would be advisable to remove elements embedded into the surface. The simplest method is chemical etching or electrochemical one. Nevertheless, these procedures should not significantly change the parameters of the surface. Among many possible reagents only a few fulfills all the above conditions. In addition, processing should not impair corrosion resistance of titanium, which is one of the most important factors determining its use as a prosthetic restoration in the mouth. The study presented results of corrosion resistance of titanium used to make prosthetic components by means of casting method, which were subjected to chemical processing designed to remove the embedded abrasive particles. The aim of the study was to investigate whether etching with selected reagents affects the corrosion resistance of titanium castings. For etching the following reagents were used: 30% HNO3 + 3% HF + H2O, HNO3+ HF+ glycerol (1:2:3, 4% HF in H2O2, 4% HF in H2O, with a control sandblasted sample, not subjected to etching. Tests demonstrated that the etching affected corrosion properties of test samples, in each case the reduction of the corrosion potential occurred - possibly due to the removal of particles of Al2O3 from the surface and activation of the surface. None of the samples underwent pitting corrosion as a result

  10. Influence of the nucleation layer annealing atmosphere on the resistivity of GaN grown by metalorganic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Weike, E-mail: luowk688@163.com; Li, Liang; Li, Zhonghui; Dong, Xun; Peng, Daqing; Zhang, Dongguo; Xu, Xiaojun

    2015-06-05

    Graphical abstract: LT-PL spectra of GaN samples A, B and C with sheet resistance of 1.1 × 10{sup 4} Ω/sq, 5.5 × 10{sup 4} Ω/sq and 1.0 × 10{sup 8} Ω/sq, respectively. - Highlights: • HR-GaN was fabricated by optimizing the nucleation layer annealing (NL) atmosphere. • The morphology of NLs annealed in different atmosphere has been investigated. • The resistance of GaN increased with density of edge type threading dislocations. • The PL results indicate that the HR-GaN is achieved due to the compensation of acceptor states. - Abstract: High-resistance (HR) GaN with sheet resistance of 1.0 × 10{sup 8} Ω/sq was grown on sapphire substrates using metal organic chemical vapor deposition. Sheet resistance of the GaN film increases 4 orders of magnitude by changing the nucleation layer (NL) annealing atmosphere from H{sub 2} to N{sub 2}. It is observed that the morphology of the NLs strongly depends on the annealing atmosphere. The analysis results based on high-resolution X-ray diffraction (HR-XRD) and etch pit density (EPD) measurements demonstrate that the density of edge-type threading dislocations increases with the proportion of the N{sub 2} in the annealing atmosphere. Photoluminescence (PL) spectra is employed to analyze the optical properties of GaN films. The XRD and PL results indicate the primary compensating mechanism is due to acceptor levels introduced by the increase in edge-type threading dislocations density. It is concluded that the annealing atmosphere of the NL controls sizes and densities of the nucleation islands, which affect electrical properties of GaN epitaxial films through changing the ratio of edge to screw/mixed-type threading dislocations.

  11. The Role of Chemical Transport in the Decay Resistance of Modified Wood. In: M

    Science.gov (United States)

    Samuel L. Zelinka; Rebecka Ringman; Annica Pulgard; Emil Engelund Thybring; Joseph E. Jakes; Klaus Richter

    2015-01-01

    A 2014 review by Ringman et al. examined established theories addressing why modified wood has increased decay resistance and concluded that the most probable cause of inhibition and/or delay of the initiation of brown rot decay is lowering the equilibrium moisture content for given environmental conditions. A 2013 paper by Jakes et al...

  12. Physical–chemical properties, separation performance, and fouling resistance of mixed-matrix ultrafiltration membranes

    KAUST Repository

    Hoek, Eric M.V.

    2011-12-01

    Herein we report on the formation and characterization of mixed-matrix ultrafiltration (UF) membranes hand-cast by nonsolvent induced phase inversion. We evaluated nanometer-to-micrometer sized inorganic fillers (silver, copper, silica, zeolite, and silver-zeolite) materials with polysulfone (PSf) as the polymeric dispersing matrix. In general, mixed-matrix membranes were rougher, more hydrophilic, and more mechanically robust. Only sub-micron zeolite-PSf mixed-matrix membranes exhibited simultaneous improvements in water permeability and solute selectivity; all other mixed-matrix membranes were more permeable, but less selective due to defects associated with poor polymer-filler binding. Protein and bacterial fouling resistance of mixed-matrix membranes containing silver, zeolite, and silver-zeolite nanoparticles were compared to a low-fouling, poly(acrylonitrile) (PAN) UF membrane. Zeolite and silver containing membranes exhibited better protein fouling resistance (due to higher hydrophilicity), whereas silver and silver-zeolite based membranes produce better bacterial fouling resistance due to antimicrobial properties. Overall, zeolite-PSf and silver exchanged zeolite-PSf membranes offered the best combination of improved permeability, selectivity, and fouling resistance - superior to the commercial PAN membrane. © 2011 Elsevier B.V.

  13. Pesticide resistance from historical agricultural chemical exposure in Thamnocephalus platyurus (Crustacea: Anostraca)

    Energy Technology Data Exchange (ETDEWEB)

    Brausch, John M. [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, 1207 Gilbert Dr, Lubbock, TX 79416 (United States)], E-mail: john.brausch@ttu.edu; Smith, Philip N. [Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, 1207 Gilbert Dr, Lubbock, TX 79416 (United States)

    2009-02-15

    Extensive pesticide usage in modern agriculture represents a considerable anthropogenic stressor to freshwater ecosystems throughout the United States. Acute toxicity of three of the most commonly used agricultural pesticides (Methyl Parathion 4ec, Tempo SC Ultra, Karmex DF, and DDT) was determined in two different wild-caught strains of the fairy shrimp Thamnocephalus platyurus. Fairy shrimp collected from playas surrounded by native grasslands were between 200% and 400% more sensitive than fairy shrimp derived from playas in agricultural watersheds for Methyl Parathion 4ec, Tempo SC Ultra, and Karmex DF, likely due to the development of resistance. Additionally, reduced sensitivity to DDT was observed among fairy shrimp from agriculturally-impacted playas as compared to those from native grassland-dominated playas. These data suggest that fairy shrimp inhabiting playas in agricultural regions have developed some degree of resistance to a variety of agrochemicals in response to historical usage. - This manuscript discusses the potential effects of long-term pesticide usage on the development of resistance and cross-resistance on a non-target aquatic invertebrate.

  14. Small signal microwave amplifier design

    CERN Document Server

    Grosch, Theodore

    2000-01-01

    This book explains techniques and examples for designing stable amplifiers for high-frequency applications in which the signal is small and the amplifier circuit is linear. An in-depth discussion of linear network theory provides the foundation needed to develop actual designs. Examples throughout the book will show you how to apply the knowledge gained in each chapter leading to the complex design of low noise amplifiers. Many exercises at the end of each chapter will help students to practice their skills. The solutions to these design problems are available in an accompanying solutions book

  15. Sulfonamides identified as plant immune-priming compounds in high-throughput chemical screening increase disease resistance in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Yoshiteru eNoutoshi

    2012-10-01

    Full Text Available Plant activators are agrochemicals that protect crops from diseases by activating the plant immune system. To isolate lead compounds for use as practical plant activators, we screened 2 different chemical libraries composed of various bioactive substances by using an established screening procedure that can selectively identify immune-priming compounds. We identified and characterized a group of sulfonamide compounds—sulfameter, sulfamethoxypyridazine, sulfabenzamide, and sulfachloropyridazine—among the various isolated candidate molecules. These sulfonamide compounds enhanced the avirulent Pseudomonas-induced cell death of Arabidopsis suspension cell cultures and increased disease resistance in Arabidopsis plants against both avirulent and virulent strains of the bacterium. These compounds did not prevent the growth of pathogenic bacteria in minimal liquid media at 200 µM. They also did not induce the expression of defense-related genes in Arabidopsis seedlings, at least not at 24 and 48 h after treatment, suggesting that they do not act as salicylic acid analogs. In addition, although sulfonamides are known to be folate biosynthesis inhibitors, the application of folate did not restore the potentiation effects of the sulfonamides on pathogen-induced cell death. Our data suggest that sulfonamides potentiate Arabidopsis disease resistance by their novel chemical properties.

  16. Acid-resistant organic coatings for the chemical industry: a review

    DEFF Research Database (Denmark)

    Møller, Victor Buhl; Dam-Johansen, Kim; Frankær, Sarah Maria Grundahl

    2017-01-01

    Industries that work with acidic chemicals in their processes need to make choices on how to properly contain the substances and avoid rapid corrosion of equipment. Certain organic coatings and linings can be used in such environments, either to protect vulnerable construction materials, or...

  17. Controlling the resistivity gradient in aluminum-doped zinc oxide grown by plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Ponomarev, M. V.; Verheijen, M. A.; Keuning, W.; van de Sanden, M. C. M.; Creatore, M.

    2012-08-01

    Aluminum-doped ZnO (ZnO:Al) grown by chemical vapor deposition (CVD) generally exhibit a major drawback, i.e., a gradient in resistivity extending over a large range of film thickness. The present contribution addresses the plasma-enhanced CVD deposition of ZnO:Al layers by focusing on the control of the resistivity gradient and providing the solution towards thin (≤300 nm) ZnO:Al layers, exhibiting a resistivity value as low as 4 × 10-4 Ω cm. The approach chosen in this work is to enable the development of several ZnO:Al crystal orientations at the initial stages of the CVD-growth, which allow the formation of a densely packed structure exhibiting a grain size of 60-80 nm for a film thickness of 95 nm. By providing an insight into the growth of ZnO:Al layers, the present study allows exploring their application into several solar cell technologies.

  18. Synthesis of thermal and chemical resistant oxygen barrier starch with reinforcement of nano silicon carbide.

    Science.gov (United States)

    Dash, Satyabrata; Swain, Sarat K

    2013-09-12

    Starch/silicon carbide (starch/SiC) bionanocomposites were synthesized by solution method using different wt% of silicon carbide with starch matrix. The interaction between starch and silicon carbide was studied by Fourier transform infrared (FTIR) spectroscopy. The structure of the bionanocomposites was investigated by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). Thermal property of starch/SiC bionanocomposites was measured and a significant enhancement of thermal resistance was noticed. The oxygen barrier property of the composites was studied and a substantial reduction in permeability was observed as compared to the virgin starch. The reduction of oxygen permeability with enhancement of thermal stability of prepared bionanocomposites may enable the materials suitable for thermal resistant packaging and adhesive applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Improved resistance of chemically-modified nanocellulose against thermally-induced depolymerization.

    Science.gov (United States)

    Agustin, Melissa B; Nakatsubo, Fumiaki; Yano, Hiroyuki

    2017-05-15

    The study demonstrated the improvement in the resistance of nanocellulose against thermally-induced depolymerization by esterification with benzoyl (BNZ) and pivaloyl (PIV). The change in the degree of polymerization (DP) and molecular weight distribution (MWD) after thermal treatment in nitrogen and in air was investigated using viscometry and gel permeation chromatography. BNZ and PIV nanocellulose esters without α-hydrogens gave higher DP and narrower MWD than pure bacterial cellulose; and the acetyl and myristoyl esters, which possess α-hydrogens. Results also showed that when depolymerization is suppressed, thermal discoloration is also reduced. Resistance against depolymerization inhibits the formation of reducing ends which can be active sites for thermal discoloration. Finally, the findings suggest that benzoylation and pivaloylation can be an excellent modification technique to improve the thermal stability of nanocellulose. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Correlation of Chemical Compositions of Cassava Varieties to Their Resistance to Prostephanus truncatus Horn (Coleoptera: Bostrichidae)

    Science.gov (United States)

    Osipitan, Adebola A.; Sangowusi, Victoria T.; Lawal, Omoniyi I.; Popoola, Kehinde O.

    2015-01-01

    The preference of cassava as a major host by Prostephanus truncatus Horn is a major constraint to ample production of cassava, Manihot esculenta Crantz and storage. This study analyzed the nutritional and secondary metabolite compositions in 15 cassava varieties, evaluated levels of damage and reproduction by P. truncatus, and assessed their resistance to attack. One hundred grams of dried cassava chips in 250-ml Kilner jars were infested with 10 adult larger grain borerof 0–10 days old and held for 3 months. The nutritional and secondary metabolites compositions of the dry cassava chips were determined using the method of Association of Analytical Chemists . Chip perforation rates in the cassava varieties ranged from 17.7 to 71.6%. The weight of cassava powder varied by about threefold. The final number of larger grain borer in the cassava varieties varied by about sixfold with 63 in 01/0040 and 379 in 01/1368. Hydrocyanic acid content content varied by over 10-fold and correlated negatively with number of larger grain borer. Flavonoid content varied by ∼10%. Tannins and saponin content of the cassava negatively correlated with number of adult P. truncatus. The cassava varieties 95/0166, 92/0326, 01/0040, 05/0024, and 34 91934 had selection index 0.8 were classified as susceptible. The resistance to high damage in the resistant varieties was conferred by secondary metabolites such as tannins, saponins, alkaloids, and hydrocyanic acid content. The genetic variation in cassava varieties could be explored to breed resistant cassava varieties for use in larger grain borer-endemic areas. PMID:25700536

  1. PID Controller with Operational Amplifier

    Directory of Open Access Journals (Sweden)

    Cristian Paul Chioncel

    2009-01-01

    Full Text Available The paper presents a PID controller made with LM741 operational amplifier that implement the PID controllers laws and allow for a widerange of applications of in the field of automatic control of technicalprocesses and systems.

  2. Linearization of broadband microwave amplifier

    Directory of Open Access Journals (Sweden)

    Đorić Aleksandra

    2014-01-01

    Full Text Available The linearization of broadband power amplifier for application in the frequency range 0.9-1.3 GHz is considered in this paper. The amplifier is designed for LDMOSFET characterized by the maximum output power 4W designing the broadband lumped element matching circuits and matching circuits in topologies that combines LC elements and transmission lines. The linearization of the amplifier is carried out by the second harmonics of the fundamental signals injected at the input and output of the amplifier transistor. The effects of linearization are considered for the case of two sinusoidal signals separated in frequency by different intervals up to 80 MHz ranging input power levels to saturation. [Projekat Ministarstva nauke Republike Srbije, br. TR-32052

  3. Superluminal waves in amplifying media

    Energy Technology Data Exchange (ETDEWEB)

    Oraevsky, Anatolii N [P.N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    1998-12-31

    In amplifying media steady-state waves can travel faster than the speed of light in vacuum without violating the principles of special relativity. The possibility of generating superluminal waves in induced elementary particle production processes is discussed. (methodological notes)

  4. Operational amplifiers theory and design

    CERN Document Server

    Huijsing, Johan

    2017-01-01

    This proven textbook guides readers to a thorough understanding of the theory and design of operational amplifiers (OpAmps). The core of the book presents systematically the design of operational amplifiers, classifying them into a periodic system of nine main overall configurations, ranging from one gain stage up to four or more stages. This division enables circuit designers to recognize quickly, understand, and choose optimal configurations. Characterization of operational amplifiers is given by macro models and error matrices, together with measurement techniques for their parameters. Definitions are given for four types of operational amplifiers depending on the grounding of their input and output ports. Many famous designs are evaluated in depth, using a carefully structured approach enhanced by numerous figures. In order to reinforce the concepts introduced and facilitate self-evaluation of design skills, the author includes problems with detailed solutions, as well as simulation exercises. Provides te...

  5. Self-biased transconductance amplifier

    Science.gov (United States)

    Amendola, Gilles; Blanchard, Yves; Exertier, Anne; Spirkovitch, Serge; Lu, Guo N.; Alquie, George

    1999-09-01

    A CMOS, self-biased transconductance amplifier has been designed to be associated and integrated with a silicon capacitive microphone. To meet requirements especially on gain sensitivity, power consumption, and minimization of parasite capacitance effect, we have proposed a cascode structure with the cascode transistor source used as signa input. Switched-capacitor techniques have been applied for realizing self-bias for the amplifier and ensuring its high- gain operation. The proposed amplifier has been designed and fabricated in a 0.8 micrometers CMOS process. It has a surface area of 210 micrometers by 170 micrometers . Experimental results obtained from measuring the fabricated chip show a high-gain sensitivity and a low power dissipation for the amplifier. Results of simulations and measurements have been discussed.

  6. New Packaging for Amplifier Slabs

    Energy Technology Data Exchange (ETDEWEB)

    Riley, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Thorsness, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Suratwala, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Steele, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rogowski, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-03-18

    The following memo provides a discussion and detailed procedure for a new finished amplifier slab shipping and storage container. The new package is designed to maintain an environment of <5% RH to minimize weathering.

  7. A Mathematical Model of a Simple Amplifier Using a Ferroelectric Transistor

    Science.gov (United States)

    Sayyah, Rana; Hunt, Mitchell; MacLeod, Todd C.; Ho, Fat D.

    2009-01-01

    This paper presents a mathematical model characterizing the behavior of a simple amplifier using a FeFET. The model is based on empirical data and incorporates several variables that affect the output, including frequency, load resistance, and gate-to-source voltage. Since the amplifier is the basis of many circuit configurations, a mathematical model that describes the behavior of a FeFET-based amplifier will help in the integration of FeFETs into many other circuits.

  8. Impedance of the Microstrip SQUID Amplifier

    Science.gov (United States)

    Therrien, Roy; Kinion, Darin; Mueck, Michael; Clarke, John

    2003-03-01

    We present measurements of the input impedance of microstrip SQUID amplifiers cooled to 4.2 K. A low-loss transmission line model fits the real and imaginary parts of this impedance quite accurately. We map the low-loss transmission line model into an equivalent parallel RLC circuit in which a resistance R, inductance L, and capacitance C are calculated from the characteristic impedance and attenuation factor determined from fits to the input impedance data. Using this equivalent RLC circuit, we model the microstrip SQUID and input network with a lumped circuit model which accurately predicts the observed gain of the amplifier. We find that the gain is maximized when the input circuit is critically matched, with the imaginary part of the input impedance summing to zero and the real part equal to the 50 ohm resistance of the coaxial input line. Work in progress is aimed at expressing the equivalent circuit parameters in terms of the device parameters. This work was supported by DOE.

  9. Field Effect Transistor /FET/ circuit for variable gin amplifiers

    Science.gov (United States)

    Spaid, G. H.

    1969-01-01

    Amplifier circuit using two FETs combines improved input and output impedances with relatively large signal handling capability and an immunity from adverse effects of automatic gain control. Circuit has sources and drains in parallel plus a resistive divider for signal and bias to either of the gate terminals.

  10. Hybrid optical: electron-beam resists

    Science.gov (United States)

    Lennon, D. M.; Spector, S. J.; Fedynyshyn, T. H.; Lyszczarz, T. M.; Rothschild, M.; Thackeray, J.; Spear-Alfonso, K.

    2007-03-01

    Combining optical and electron beam exposures on the same wafer level is an attractive approach for extending the usefulness of current generation optical tools. This technique requires high-performance hybrid resists that perform equally well with optical and e-beam tools. In this paper Rohm and Haas EPIC TM 2340, a 193-nm chemically amplified photoresist, is used in a hybrid exposure role. The e-beam tool was used to pattern 45 nm half-pitch features and a 193- nm immersion stepper was used to pattern 60-nm half-pitch features in the same resist layer. The effects of processing parameters and delay times were investigated.

  11. Surge-Resistant Nanocomposite Enameled Wire Using Silica Nanoparticles with Binary Chemical Compositions on the Surface

    Directory of Open Access Journals (Sweden)

    Jeseung Yoo

    2015-01-01

    Full Text Available We developed polyesterimide (PEI nanocomposite enameled wires using surface-modified silica nanoparticles with binary chemical compositions on the surface. The modification was done using silanes assisted by ultrasound, which facilitated high density modification. Two different trimethoxysilanes were chosen for the modification on the basis of resemblance of chemical compositions on the silica surface to PEI varnish. The surface-modified silica was well dispersed in PEI varnish, which was confirmed by optical observation and viscosity measurement. The glass transition temperature of the silica-PEI nanocomposite increased with the silica content. The silica-dispersed PEI varnish was then used for enameled wire fabrication. The silica-PEI nanocomposite enameled wire exhibited a much longer lifetime compared to that of neat PEI enameled wire in partial discharge conditions.

  12. High-temperature-resistant chemical composition Bragg gratings in Er3+-doped optical fiber

    Science.gov (United States)

    Trpkovski, S.; Kitcher, D. J.; Baxter, G. W.; Collins, S. F.; Wade, S. A.

    2005-03-01

    Chemical composition gratings (CCGs), unlike standard fiber Bragg gratings (FBGs), do not suffer a significant decrease in reflectance or an irreversible wavelength shift when they are exposed to elevated temperatures. To date, the growth of CCGs has been related to the fluorine content of the fibers in which they are written. It is shown that FBGs with high thermal stability, resembling CCGs, can be fabricated in Er3+-doped optical fibers that do not contain any fluorine.

  13. Corrosive Resistant Diamond Coatings for the Acid Based Thermo-Chemical Hydrogen Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Mark A. Prelas

    2009-06-25

    This project was designed to test diamond, diamond-like and related materials in environments that are expected in thermochemical cycles. Our goals were to build a High Temperature Corrosion Resistance (HTCR) test stand and begin testing the corrosive properties of barious materials in a high temperature acidic environment in the first year. Overall, we planned to test 54 samples each of diamond and diamond-like films (of 1 cm x 1 cm area). In addition we use a corrosion acceleration method by treating the samples at a temperature much larger than the expected operating temperature. Half of the samples will be treated with boron using the FEDOA process.

  14. In vitro antibacterial and chemical properties of essential oils including native plants from Brazil against pathogenic and resistant bacteria.

    Science.gov (United States)

    Barbosa, Lidiane Nunes; Probst, Isabella da Silva; Andrade, Bruna Fernanda Murbach Teles; Alves, Fernanda Cristina Bérgamo; Albano, Mariana; da Cunha, Maria de Lourdes Ribeiro de Souza; Doyama, Julio Toshimi; Rall, Vera Lúcia Mores; Fernandes Júnior, Ary

    2015-01-01

    The antimicrobials products from plants have increased in importance due to the therapeutic potential in the treatment of infectious diseases. Therefore, we aimed to examine the chemical characterisation (GC-MS) of essential oils (EO) from seven plants and measure antibacterial activities against bacterial strains isolated from clinical human specimens (methicillin-resistant Staphylococcus aureus (MRSA) and sensitive (MSSA), Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium) and foods (Salmonella Enteritidis). Assays were performed using the minimal inhibitory concentration (MIC and MIC90%) (mg/mL) by agar dilution and time kill curve methods (log CFU/mL) to aiming synergism between EO. EO chemical analysis showed a predominance of terpenes and its derivatives. The highest antibacterial activities were with Cinnamomun zeylanicum (0.25 mg/mL on almost bacteria tested) and Caryophyllus aromaticus EO (2.40 mg/mL on Salmonella Enteritidis), and the lowest activity was with Eugenia uniflora (from 50.80 mg/mL against MSSA to 92.40 mg/mL against both Salmonella sources and P. aeruginosa) EO. The time kill curve assays revealed the occurrence of bactericide synergism in combinations of C. aromaticus and C. zeylanicum with Rosmarinus. officinalis. Thus, the antibacterial activities of the EO were large and this can also be explained by complex chemical composition of the oils tested in this study and the synergistic effect of these EO, yet requires further investigation because these interactions between the various chemical compounds can increase or reduce (antagonism effect) the inhibitory effect of essential oils against bacterial strains.

  15. Increased pattern transfer fidelity ZEP 520A during reactive ion etching through chemical modifications by additional dosing of the electron beam resist.

    Energy Technology Data Exchange (ETDEWEB)

    Czaplewski, D. A.; Ocola, L. E. (Center for Nanoscale Materials)

    2011-03-01

    This article describes a postdevelopment, additional electron exposure to enhance the etch selectivity and improve pattern transfer fidelity of an electron beam resist, ZEP 520A, through chemical changes of the resist. After the critical features were patterned and developed, the resist was exposed at 5 kV accelerating voltage to a second dose of electrons ranging from 300 to 300,000 {micro}C/cm{sup 2}. The etch rate of the resist decreased by approximately 25% in a CHF{sub 3} and O{sub 2} plasma. More critically, the fidelity of the pattern transfer was improved. Infrared and Raman spectroscopies were used to characterize the resist before and after electron beam exposure for doses up to 3000 {micro}C/cm{sup 2}. The carbonyl bonding in the polymer showed significant changes after electron beam exposure that can be associated with improvement in the etch performance of this resist.

  16. Increased pattern transfer fidelity of ZEP 520A during reactive ion etching through chemical modifications by additional dosing of the electron beam resist

    Energy Technology Data Exchange (ETDEWEB)

    Czaplewski, D. A.; Ocola, L. E. (Center for Nanoscale Materials)

    2011-01-01

    This article describes a postdevelopment, additional electron exposure to enhance the etch selectivity and improve pattern transfer fidelity of an electron beam resist, ZEP 520A, through chemical changes of the resist. After the critical features were patterned and developed, the resist was exposed at 5 kV accelerating voltage to a second dose of electrons ranging from 300 to 300,000 {micro}C/cm{sup 2}. The etch rate of the resist decreased by approximately 25% in a CHF{sub 3} and O{sub 2} plasma. More critically, the fidelity of the pattern transfer was improved. Infrared and Raman spectroscopies were used to characterize the resist before and after electron beam exposure for doses up to 3000 {micro}C/cm{sup 2}. The carbonyl bonding in the polymer showed significant changes after electron beam exposure that can be associated with improvement in the etch performance of this resist.

  17. The Role of Stitch Yarn on the Delamination Resistance in Non-crimp Fabric: Chemical and Physical Interpretation

    Science.gov (United States)

    Shiino, Marcos Yutaka; Pelosi, Tatiane Scarabel; Cioffi, Maria Odila Hilário; Donadon, Mauricio Vicente

    2017-03-01

    In a 3D preform, the out-of-plane reinforcement is effective for decelerating or suppressing the delamination process as the non-crimp fabric does not connect the neighboring laminae effectively. Hence, the interlaminar strength of the stitched laminae is supposed to behave in the same way as a regular unidirectional composite. In order to determine whether or not the stitched yarns contribute to the interlaminar fracture toughness, this study determinated the delamination resistance of a quasi-isotropic laminate. The analysis was based on interlaminar fracture toughness ( G Ic) and propagation energy curve in tests conducted in mode I opening with double cantilever beam specimen geometry. The results of fracture toughness as well as strain energy for propagation were compared to their fracture surface. A decrease in the propagation energy prevailed in the surface because the stitch yarn replaced the carbon fiber/epoxy interface, which has better chemical affinities, i.e., covalent bonds.

  18. Fate of antibiotic resistance genes in mesophilic and thermophilic anaerobic digestion of chemically enhanced primary treatment (CEPT) sludge.

    Science.gov (United States)

    Jang, Hyun Min; Shin, Jingyeong; Choi, Sangki; Shin, Seung Gu; Park, Ki Young; Cho, Jinwoo; Kim, Young Mo

    2017-11-01

    Anaerobic digestion (AD) of chemically enhanced primary treatment (CEPT) sludge and non-CEPT (conventional sedimentation) sludge were comparatively operated under mesophilic and thermophilic conditions. The highest methane yield (692.46±0.46mL CH 4 /g VS removed in CEPT sludge) was observed in mesophilic AD of CEPT sludge. Meanwhile, thermophilic conditions were more favorable for the removal of total antibiotic resistance genes (ARGs). In this study, no measurable difference in the fates and removal of ARGs and class 1 integrin-integrase gene (intI1) was observed between treated non-CEPT and CEPT sludge. However, redundancy analysis indicated that shifts in bacterial community were primarily accountable for the variations in ARGs and intI1. Network analysis further revealed potential host bacteria for ARGs and intI1. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Effect of chemical systemic acquired resistance elicitors on avenanthramide biosynthesis in oat (Avena sativa).

    Science.gov (United States)

    Wise, Mitchell L

    2011-07-13

    Oats produce a group of phenolic antioxidants termed avenanthramides. These metabolites are, among food crops, unique to oats and have shown, in experimental systems, certain desirable nutritional characteristics such as inhibiting atherosclerotic plaque formation and reducing inflammation. Avenanthramides occur in both the leaves and grain of oat. In the leaves they are expressed as phytoalexins in response to crown rust (Puccina coronata) infection. The experiments reported here demonstrate that avenanthramide levels in vegetative tissue can be enhanced by treatment with benzothiadiazole (BTH), an agrochemical formulated to elicit systemic acquired resistance (SAR). The response to BTH was dramatically stronger than those produced with salicylic acid treatment. The roots of BTH treated plants also showed a smaller but distinct increase in avenanthramides. The dynamics of the root avenanthramide increase was substantially slower than that observed in the leaves, suggesting that avenanthramides might be transported from the leaves.

  20. EMI-resilient amplifier circuits

    CERN Document Server

    van der Horst, Marcel J; Linnenbank, André C

    2014-01-01

    This book enables circuit designers to reduce the errors introduced by the fundamental limitations and electromagnetic interference (EMI) in negative-feedback amplifiers.  The authors describe a systematic design approach for application specific negative-feedback amplifiers, with specified signal-to-error ratio (SER).  This approach enables designers to calculate noise, bandwidth, EMI, and the required bias parameters of the transistors used in  application specific amplifiers in order to meet the SER requirements.   ·         Describes design methods that incorporate electromagnetic interference (EMI) in the design of application specific negative-feedback amplifiers; ·         Provides designers with a structured methodology to avoid the use of trial and error in meeting signal-to-error ratio (SER) requirements; ·         Equips designers to increase EMI immunity of the amplifier itself, thus avoiding filtering at the input, reducing the number of components and avoiding detr...

  1. Resistant starch content, in vitro starch digestibility and physico-chemical properties of flour and starch from Thai bananas

    Directory of Open Access Journals (Sweden)

    Nednapis Vatanasuchart

    2012-07-01

    Full Text Available Flour and starch were prepared from six Thai banana cultivars: Kluai Hom, Kluai Khai,Kluai Lebmuenang, Kluai Namwa, Kluai Hakmuk and Kluai Hin, and their resistant starch (RS, invitro starch digestibility and physico-chemical properties were determined. The RS content of theflour is 52.2-68.1%, with flour from Kluai Hin containing the highest amount of RS, followed by thatfrom Kluai Hakmuk. The starch has a higher RS content (70.1-79.2%, the highest value comingfrom Kluai Hakmuk starch, followed by Kluai Hom starch. A significant linear relationship betweenapparent amylose and RS was observed. Interestingly, most of the flour showed a slower rate of invitro starch digestibility than that of the starch, with Kluai Hin flour exhibiting the slowest rate,followed by Kluai Namwa. Rapid viscosity analysis showed significantly higher peak viscosity of thestarch than the flour, the highest final and setback viscosity being obtained from Kluai Hin starch.Differential scanning calorimetry showed an endothermic transition enthalpy over a range of 17.4 J/gfor Kluai Lebmuenang starch to 18.6 J/g for Kluai Hin starch. X-ray diffractograms of the starchesexhibited a typical B-pattern with Kluai Hin showing the highest degree of relative crystallinity(31.3% with a sharp peak at 5.5. The overall results seemed to indicate an effect of the BBgenotype on the resistance of banana starch granules to enzymatic digestion due to amylosemolecules and the crystallinity of amylopectin.

  2. Relationship Between Lodging Resistance and Chemical Contents in Culms and Sheaths of Japonica Rice During Grain Filling

    Directory of Open Access Journals (Sweden)

    Feng-zhuan ZHANG

    2010-12-01

    Full Text Available To understand the relationship between lodging resistance and chemical component contents in culms and leaf sheaths of rice, the physical strength and maximum bearing capacity of culm, and the contents and amounts of potassium (K, silicon (Si and soluble sugars in culms and leaf sheaths were investigated using four japonica rice varieties with different lodging resistance characteristics during grain filling. There were significant differences in the total amounts of K, Si and soluble sugars in culms and leaf sheaths among the tested rice varieties. The difference in the total amount of Si was greater than that of K or soluble sugars. The physical strength and maximum bearing capacity of culm continuously decreased from heading to ripening, with a rapid decrease at the dough stage. However, the contents and total amounts of K and Si in culms and the Si content in leaf sheaths gradually increased and an accumulation of K and Si in culms was exhibited, whereas the content and total amount of K and the total amount of Si in leaf sheaths gradually decreased and an exportation of K and Si in leaf sheaths was presented. The physical strength was positively and significantly correlated with the total amounts of K and Si in culms during grain filling except that at the heading stage, the total amount of soluble sugars in culms at the heading and milky stages, the total amounts of Si and soluble sugars in leaf sheaths at the heading stage, the total amount of K in leaf sheaths at the heading and milky stages, and the maximum bearing capacity during grain filling. It is suggested that the lodging resistance of japonica rice would be improved by increasing the amount of soluble sugars in plants at the early filling stage, and enhancing the amount of Si in plants during grain filling through topdressing Si fertilizer at the early filling stage.

  3. Capacitively-coupled chopper amplifiers

    CERN Document Server

    Fan, Qinwen; Huijsing, Johan H

    2017-01-01

    This book describes the concept and design of the capacitively-coupled chopper technique, which can be used in precision analog amplifiers. Readers will learn to design power-efficient amplifiers employing this technique, which can be powered by regular low supply voltage such as 2V and possibly having a +\\-100V input common-mode voltage input. The authors provide both basic design concepts and detailed design examples, which cover the area of both operational and instrumentation amplifiers for multiple applications, particularly in power management and biomedical circuit designs. Discusses basic working principles and details of implementation for proven designs; Includes a diverse set of applications, along with measurement results to demonstrate the effectiveness of the technique; Explains advantages and drawbacks of the technique, given particular circumstances.

  4. Linearisation of RF Power Amplifiers

    DEFF Research Database (Denmark)

    Nielsen, Per Asbeck

    2001-01-01

    of circuitry such as the linearisation circuit. The amplifier has the highest output power compared to other published class B power in the same process. The design phase including the on-chip inductor and the lateral flux capacitors is described. The other test chips designed are envelope detectors. Three......This thesis deals with linearisation techniques of RF power amplifiers (PA), PA design techniques and integration of the necessary building blocks in a CMOS technology. The opening chapters introduces the theory of transmitter architectures, RF-signal representation and the principles of digital...... modulation. Furthermore different types of power amplifiers, models and measures of non-linearities are presented. A chapter is also devoted to different types of linearisation systems. The work carried out and described in this thesis can be divided into a more theoretical and system oriented treatment...

  5. Different impacts of manure and chemical fertilizers on bacterial community structure and antibiotic resistance genes in arable soils.

    Science.gov (United States)

    Liu, Peng; Jia, Shuyu; He, Xiwei; Zhang, Xuxiang; Ye, Lin

    2017-12-01

    Both manure and chemical fertilizers are widely used in modern agriculture. However, the impacts of different fertilizers on bacterial community structure and antibiotic resistance genes (ARGs) in arable soils still remain unclear. In this study, high-throughput sequencing and quantitative PCR were employed to investigate the bacterial community structure, ARGs and mobile genetic elements (MGEs) influenced by the application of different fertilizers, including chemical fertilizers, piggery manure and straw ash. The results showed that the application of fertilizers could significantly change the soil bacterial community and the abundance of Gaiella under phylum Actinobacteria was significantly reduced from 12.9% in unfertilized soil to 4.1%-7.4% in fertilized soil (P bacterial community structure but exerted little effect on soil resistome. Overall, the results of this study illustrated the different effects of different fertilizers on the soil resistome and revealed that the changes of soil resistome induced by manure application mainly resulted from alteration of bacteria community rather than the horizontal gene transfer. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Ultra Low Noise Infrared Detector Amplifier for Next Generation Standoff Detector

    Science.gov (United States)

    2016-02-18

    6  Figure 6: Noise (left) and signal (right) flow paths in a common-source amplifier with resistive feedback...24: Noise figure vs. frequency of mHEMT LNA. Noise Figure decreases as feedback resistance increases...capacitance Cd. The thermal noise arising from the detector’s finite resistance and the shot noise are the dominant sources of noise in the detector

  7. Highly Efficient Oxygen-Storage Material with Intrinsic Coke Resistance for Chemical Looping Combustion-Based CO2 Capture.

    Science.gov (United States)

    Imtiaz, Qasim; Kurlov, Alexey; Rupp, Jennifer Lilia Marguerite; Müller, Christoph Rüdiger

    2015-06-22

    Chemical looping combustion (CLC) and chemical looping with oxygen uncoupling (CLOU) are emerging thermochemical CO2 capture cycles that allow the capture of CO2 with a small energy penalty. Here, the development of suitable oxygen carrier materials is a key aspect to transfer these promising concepts to practical installations. CuO is an attractive material for CLC and CLOU because of its high oxygen-storage capacity (20 wt %), fast reaction kinetics, and high equilibrium partial pressure of oxygen at typical operating temperatures (850-1000 °C). However, despite its promising characteristics, its low Tammann temperature requires the development of new strategies to phase-stabilize CuO-based oxygen carriers. In this work, we report a strategy based on stabilization by co-precipitated ceria (CeO2-x ), which allowed us to increase the oxygen capacity, coke resistance, and redox stability of CuO-based oxygen carriers substantially. The performance of the new oxygen carriers was evaluated in detail and compared to the current state-of-the-art materials, that is, Al2 O3 -stabilized CuO with similar CuO loadings. We also demonstrate that the higher intrinsic oxygen uptake, release, and mobility in CeO2-x -stabilized CuO leads to a three times higher carbon deposition resistance compared to that of Al2 O3 -stabilized CuO. Moreover, we report a high cyclic stability without phase intermixing for CeO2-x -supported CuO. This was accompanied by a lower reduction temperature compared to state-of-the-art Al2 O3 -supported CuO. As a result of its high resistance towards carbon deposition and fast oxygen uncoupling kinetics, CeO2-x -stabilized CuO is identified as a very promising material for CLC- and CLOU-based CO2 capture architectures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Protein adsorption resistance and oxygen permeability of chemically crosslinked phospholipid polymer hydrogel for ophthalmologic biomaterials.

    Science.gov (United States)

    Goda, Tatsuro; Matsuno, Ryosuke; Konno, Tomohiro; Takai, Madoka; Ishihara, Kazuhiko

    2009-04-01

    The biomimetic structure of a polymer hydrogel bearing phosphorylcholine groups was obtained from 2-methacryloyloxyethylphosphorylcholline (MPC) and a novel crosslinker, 2-(methacryloyloxy)ethyl-N-(2-methacryloyloxy)ethyl]phosphorylcholine (MMPC), to prepare biocompatible ocular materials. MMPC is a dimethacrylate with phosphorylcholine-analogous linkage. Previous reports clarified that the affinity of MMPC to MPC enables the water contents and mechanical properties of the poly(MPC) hydrogels to be varied without disturbing the bulk phases. In this study, we examined the protein adsorption resistance, water wettability, oxygen permeability, and electrolyte permeability of the mechanically enhanced poly(MPC) hydrogel crosslinked with MMPC. The amount of protein adsorbed on this hydrogel was 0.9 microg/cm(2), which accounted for 30% of Omafilcon A and 3% of Etafilcon A. Water contact angle experiments revealed the high wettability of the poly(MPC) hydrogels. The oxygen permeability and NaCl diffusion constant of the poly(MPC) hydrogels were 64 barrer and 48 x 10(-6) cm(2)/s, respectively. This high permeability resulted from the high water content, similar to the case of the human cornea. These results suggested that poly(MPC) hydrogels have good potential for use in ophthalmologic biomaterials.

  9. SADP for BEOL using chemical slimming with resist mandrel for beyond 22nm nodes

    Science.gov (United States)

    Jang, Linus; Raghunathan, Sudhar; Ryan, E. Todd; Kye, Jongwook; Levinson, Harry J.; Dunn, Shannon; Hetzer, David; Kawakami, Shinichiro; Huli, Lior

    2012-03-01

    The fundamental limits of optical lithography have driven semiconductor processing research to push the envelope. Double patterning (DP) techniques including litho-etch litho-etch (LELE), litho-litho etch (LLE), and self-aligned double patterning (SADP) have become standard vernacular for near term semiconductor processing as EUV is not yet ready for high volume production. The challenge, even with techniques like LLE and SADP, remains that printing small lines on tight pitches (for LLE) or even small lines on relaxed pitches for mandrel/spacer combinations is not trivial. We have demonstrated a track-based slimming technique that can produce sub-25 nm resist lines for either SADP or LLE DP processes. Our work includes results for varying shrink amounts at different target critical dimensions (CD) and for multiple pitches. We also investigated CD uniformity (CDU) and defectivity. In particular, optimization of the amount of slimming is critical as it allows for much greater process latitude at the lithography step. In addition to the lithography work, we have continued the processing for both integration schemes to include oxide deposition and etch for SADP and through etch performance for DP. We have demonstrated sub 45 nm pitch structures. The wide variety of process uses, as well as the ability to achieve a large range of shrink amounts shows that track based slimming is a viable solution to achieve target CD and pitch values for sub 22 nm technology node.

  10. Superhydrophobic powder additives to enhance chemical agent resistant coating systems for military equipment for the U.S. Marine Corps (USMC) Corrosion Prevention and Control (CPAC) Program

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, Steven J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Armstrong, Beth L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Haynes, James A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-07-01

    The primary goal of the CPAC program at ORNL was to explore the feasibility of introducing various silica-based superhydrophobic (SH) powder additives as a way to improve the corrosion resistance of US Department of Defense (DOD) military-grade chemical agent resistant coating (CARC) systems. ORNL had previously developed and patented several SH technologies of interest to the USMC, and one of the objectives of this program was to identify methods to incorporate these technologies into the USMC’s corrosion-resistance strategy. This report discusses findings of the CPAC and their application.

  11. Investigation of Radiation and Chemical Resistance of Flexible HLW Transfer Hose

    Energy Technology Data Exchange (ETDEWEB)

    E. Skidmore; Billings, K.; Hubbard, M.

    2010-03-24

    A chemical transfer hose constructed of an EPDM (ethylene-propylene diene monomer) outer covering with a modified cross-linked polyethylene (XLPE) lining was evaluated for use in high level radioactive waste transfer applications. Laboratory analysis involved characterization of the hose liner after irradiation to doses of 50 to 300 Mrad and subsequent exposure to 25% NaOH solution at 93 C for 30 days, simulating 6 months intermittent service. The XLPE liner mechanical and structural properties were characterized at varying dose levels. Burst testing of irradiated hose assemblies was also performed. Literature review and test results suggest that radiation effects below doses of 100 kGy are minimal, with acceptable property changes to 500 kGy. Higher doses may be feasible. At a bounding dose of 2.5 MGy, the burst pressure is reduced to the working pressure (1.38 MPa) at room temperature. Radiation exposure slightly reduces liner tensile strength, with more significant decrease in liner elongation. Subsequent exposure to caustic solutions at elevated temperature slightly increases elongation, suggesting an immersion/hydrolytic effect or possible thermal annealing of radiation damage. This paper summarizes the laboratory results and recommendations for field deployment.

  12. Evaluating resist degradation during reactive ion oxide etching using 193 nm model resist formulations

    Science.gov (United States)

    May, M. J.; Mortini, B.; Sourd, C.; Perret, D.; Chung, D. W.; Barclay, G.; Brochon, C.; Hadziioannou, G.

    2006-03-01

    The weaker etch resistance of 193 nm resists1 is raising questions concerning their usability for the coming nodes as a single layer resist. We have found that 193 nm positive tone resists, that have been designed2 incorporating etch resistant groups like adamantyl or isobornyl 3-7, exhibit chemical modifications concerning these grafted functions while undergoing an oxide etch step. Previously performed experiments have pointed out that the photoacid generator (PAG) that is still contained in the unexposed regions of the sacrificial layer might be a reason for the modifications in the chemical buildup of this resists. Therefore, this work has focused on evaluating the impact of reactive ion oxide etching 8-10 on 193nm materials, for positive and negative tone chemically amplified resists. We used Thermo Gravimetric Analysis (TGA), Fourier Transformed Infra Red Spectroscopy (FTIR) and Atomic Force Microscopy (AFM) in order to check model formulations based on PHS, methacrylate or cyclic olefin polymers with various protecting groups having different activation energies and formulated with or without PAG and in order to understand the impact of the photoactive compound in the resist degradation behavior during plasma etch.

  13. Cryogenic MMIC Low Noise Amplifiers

    Science.gov (United States)

    Weinreb, S.; Gaier, T.; Fernandez, J.; Erickson, N.; Wielgus, J.

    2000-01-01

    Monolithic (MMIC) and discrete transistor (MIC) low noise amplifiers are compared on the basis of performance, cost, and reliability. The need for cryogenic LNA's for future large microwave arrays for radio astronomy is briefly discussed and data is presented on a prototype LNA for the 1 to 10 GZH range along with a very wideband LNA for the 1 to 60 GHz range.

  14. Compressed magnetic flux amplifier with capacitive load

    Energy Technology Data Exchange (ETDEWEB)

    Stuetzer, O.M.

    1980-03-01

    A first-order analysis is presented for a compressed magnetic flux (CMF) current amplifier working into a load with a capacitive component. Since the purpose of the investigation was to gain a general understanding of the arrangement, a number of approximations and limitations were accepted. The inductance of the transducer varies with time; the inductance/resistance/capacitance (LRC) circuit therefore is parametric and solutions are different for the stable regime (high C), the oscillation regime (low C), and the transition case. Solutions and performance depend strongly on circuit boundary conditions, i.e., energization of the circuit by either an injected current or by an applied capacitor charge. The behavior of current and energy amplification for the various cases are discussed in detail. A number of experiments with small CMF devices showed that the first-order theory presented predicts transducer performance well in the linear regime.

  15. Horizontal transfer of antibiotic resistance genes among gram negative bacteria in sewage and lake water and influence of some physico-chemical parameters of water on conjugation process.

    Science.gov (United States)

    Shakibaie, M R; Jalilzadeh, K A; Yamakanamardi, S M

    2009-01-01

    Transfer of antibiotic resistance genes among gram negative bacteria in sewage and lake water and easy access of these bacteria to the community are major environmental and public health concern. The aim of this study was to determine transfer of the antimicrobial resistance genes from resistant to susceptible gram negative bacteria in the sewage and lake water by conjugation process and to determine the influence of some physico-chemical parameters of sewage and lake water on the transfer of these resistance genes. For this reason, we isolated 20 liter of each sewage and lake water from coconut area within university campus and Lingambudi lake respectively in Mysore city, India, during monsoon season and studied different physical parameters of the water samples like pH, temperature, conductivity turbidity and color as well as chemical parameters like BOD, COD, field DO and total chloride ion. The gram negative bacteria were isolated and identified from the above water samples using microbiological and biochemical methods and their sensitivity to different antibiotics was determined by disc diffusion break point assay. Conjugation between two multiple antibiotic resistant isolates Pseudomonas aeuginosa and E. coli as donor and E. coli Rif(r) (sensitive to antibiotics) as recipient were carried out in 5ml sterile sewage and lake water. All isolates were resistant to Am, moderately resistant to Te and E, while majority were sensitive to Cip, Gm and CAZ antibiotics. Horizontal transfer of antibiotic resistance genes by conjugation process revealed transfer of Gm, Te and E resistant genes from Ps. aeruginosa to E. coli Rif(r) recipient with mean frequency of +/- 2.3 x 10(-4) in sewage and +/- 2.6 x 10(-6) in lake water respectively Frequency of conjugation in sewage was two fold more as compared to lake water (ptransfer study revealed simultaneous transfer of above resistant markers together to the recipient cells. As the above results indicate, due to selective

  16. Comparison of Chemical Sensitivity of Fresh and Long-Stored Heat Resistant Neosartorya fischeri Environmental Isolates Using BIOLOG Phenotype MicroArray System.

    Directory of Open Access Journals (Sweden)

    Jacek Panek

    Full Text Available Spoilage of heat processed food and beverage by heat resistant fungi (HRF is a major problem for food industry in many countries. Neosartorya fischeri is the leading source of spoilage in thermally processed products. Its resistance to heat processing and toxigenicity makes studies about Neosartorya fischeri metabolism and chemical sensitivity essential. In this study chemical sensitivity of two environmental Neosartorya fischeri isolates were compared. One was isolated from canned apples in 1923 (DSM3700, the other from thermal processed strawberry product in 2012 (KC179765, used as long-stored and fresh isolate, respectively. The study was conducted using Biolog Phenotype MicroArray platforms of chemical sensitivity panel and traditional hole-plate method. The study allowed for obtaining data about Neosartorya fischeri growth inhibitors. The fresh isolate appeared to be much more resistant to chemical agents than the long-stored isolate. Based on phenotype microarray assay nitrogen compounds, toxic cations and membrane function compounds were the most effective in growth inhibition of N. fischeri isolates. According to the study zaragozic acid A, thallium(I acetate and sodium selenate were potent and promising N. fischeri oriented fungicides which was confirmed by both chemical sensitivity microplates panel and traditional hole-plate methods.

  17. THE CHEMICAL AND RADIATION RESISTANCE OF POLYPHENYLENE SULFIIDE AS ENCOUNTERED IN THE MODULAR CAUSTIC SIDE SOLVENT EXTRACTION PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.; Herman, D.; Poirier, M.; Fink, S.

    2011-06-30

    Polyphenylene sulfide (PPS) is a semicrystalline polymer with excellent engineering plastic properties and suitable processing temperatures. PPS can also be made containing branches (using a trifunctional monomer) and with crosslinked microstructure (when curing the monomer at high temperature in the presence of oxygen). PPS is made from the condensation reaction between para-dichlorobenzene and sodium sulfide with the assistance of a catalyst (to lower the activation barrier). The synthesis conditions for making PPS has evolved since its invention in the 1960's to the optimal conditions developed by the Philips Corporation in the 1970's. The resulting polymer consists of chemically stable molecular moieties such as benzene rings and ether like sulfur linkages between the aromatic rings. Polyphenylene sulfide (PPS) is extremely resistant to gamma irradiation, caustic solution, and dilute nitric acid. PPS is the material of construction for the coalescers used in the Modular Caustic-Side Solvent Extraction Unit (MCU). After applying the equivalent of 3.3 E8 rad (330 Mrad), or the equivalent of 11 years of gamma irradiation (assuming a stripping solution concentration of 7.5 Ci/gal), and several months of exposures to 3M caustic solution and caustic salt simulant, no dimensional changes nor chemical changes were detected in PPS whether the PPS was in fiber form or in a composite with E-glass fibers. However, PPS acts as a media for heterogeneous nucleation. In particular, PPS appears to favor aluminosilicate formation in saturated solutions of aluminum and silicon in caustic environments. Parallel testing, in progress, is examining the stability of PPS when exposed to the new solvent formulation under development for MCU. Preliminary data, after two months of exposure, demonstrates PPS is stable to the new solvent.

  18. Single conversion stage amplifier - SICAM

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.

    2005-12-15

    This Ph.D. thesis presents a thorough analysis of the so called SICAM - SIngle Converter stage AMplifier approach to building direct energy conversion audio power amplifiers. The mainstream approach for building isolated audio power amplifiers today consists of isolated DC power supply and Class D amplifier, which essentially represents a two stage solution, where each of the components can be viewed as separate and independent part. The proposed SICAM solution strives for direct energy conversion from the mains to the audio output, by dedicating the operation of the components one to another and integrating their functions, so that the final audio power amplifier represents a single-stage topology with higher efficiency, lower volume, less board space, lower component count and subsequently lower cost. The SICAM approach is both applicable to non-isolated and isolated audio power amplifiers, but the problems encountered in these two cases are different. Non-isolated SICAM solutions are intended for both AC mains-connected and battery-powered devices. In non-isolated mains-connected SICAMs the main idea is to simplify the power supply or even provide integrated power factor correction (PFC) functions, while still maintaining low component stress and good audio performance by generally decreasing the input voltage level to the Class D audio power amplifier. On the other hand, non-isolated battery-powered SICAMs have to cope with the ever changing battery voltage and provide output voltage levels which are both lower and higher than the battery voltage, while still being simple and single-stage energy conversion solutions. In isolated SICAMs the isolation transformer adjusts the voltage level on the secondary side to the desired level, so the main challenges here are decreasing the size of the magnetic core and reducing the number and size of bulky reactive components as much as possible. The main focus of this thesis is directed towards the isolated SICAMs and

  19. Genetic Diversity Evaluation of Moringa Oleifera, Lam From East Flores Regency Using Marker Random Amplified Polymorphic DNA (RAPD) and Its Relationship to Chemical Composition and in Vitro Gas Production

    OpenAIRE

    Kleden, Markus Miten; Soetanto, Hendrawan; Kusmartono, Kusmartono; Kuswanto, Kuswanto

    2017-01-01

    The research objective was to evaluate the genetic diversity of Moringa oleifera, Lam (MO) and its relationship to chemical composition and in vitro gas production (IVGP). Fresh MO leaves were kept frozen in ice gels pack until laboratory analysis. Four methods applied: RAPD marker for measuring DNA concentration and purification; Kjeldhal and HPLC for analysing proximate and amino acid (AA) composition; and IVGP. MO's four distinct morphology found: green, red, reddish green and aromatic gre...

  20. Integrated waveguide amplifiers for optical backplanes

    NARCIS (Netherlands)

    Yang, J.; Lamprecht, T.; Worhoff, Kerstin; Driessen, A.; Horst, F.; Horst, F.; Offrein, B.J.; Offrein, B.J.; Ay, F.; Pollnau, Markus

    Amplifier performance of Nd3+-doped polymer and Al2O3 channel waveguides at 880 nm is investigated. Tapered amplifiers are embedded between optical backplane waveguides, and a maximum 0.21 dB net gain is demonstrated.

  1. Higher order mode optical fiber Raman amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Friis, Søren Michael Mørk; Usuga Castaneda, Mario A.

    2016-01-01

    We review higher order mode Raman amplifiers and discuss recent theoretical as well as experimental results including system demonstrations.......We review higher order mode Raman amplifiers and discuss recent theoretical as well as experimental results including system demonstrations....

  2. Analog circuit design designing high performance amplifiers

    CERN Document Server

    Feucht, Dennis

    2010-01-01

    The third volume Designing High Performance Amplifiers applies the concepts from the first two volumes. It is an advanced treatment of amplifier design/analysis emphasizing both wideband and precision amplification.

  3. Cascode-based voltage-amplifier stage

    Directory of Open Access Journals (Sweden)

    Pospisilik Martin

    2017-01-01

    Full Text Available Voltage-amplifier stages are the basic components of commonly used high gain amplifiers the bias and other parameters of whose are set by the external negative feedback. The typical device that uses the voltage-amplifier stage is the operational amplifier. Similar constructions can also be created on the basis of discrete transistors. From the circuit designer’s point of view, the voltage-amplifier stage defines the crucial parameters of the whole unit - the amplification factor, dominant pole of its transfer function and the slew rate. In this paper the proposal on construction of the voltage-amplifier stage based on discrete transistors is described. When connected between the input differential amplifier and the output stage, it allows creating of cheap amplifier for HiFi applications with considerable performance.

  4. High power gas laser amplifier

    Science.gov (United States)

    Leland, Wallace T.; Stratton, Thomas F.

    1981-01-01

    A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

  5. SPS RF System Amplifier plant

    CERN Multimedia

    1977-01-01

    The picture shows a 2 MW, 200 MHz amplifier plant with feeder lines. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X.

  6. High power regenerative laser amplifier

    Science.gov (United States)

    Miller, John L.; Hackel, Lloyd A.; Dane, Clifford B.; Zapata, Luis E.

    1994-01-01

    A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse.

  7. Challenges in higher order mode Raman amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Nielsen, Kristian; Friis, Søren Michael Mørk

    2015-01-01

    A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed......A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed...

  8. Spontaneous emission from saturated parametric amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Ott, Johan Raunkjær; Steffensen, Henrik

    2009-01-01

    Noise performance of parametric amplifiers is typically calculated assuming un-depleted operation. However, in many applications especially when applied as regenerative amplifiers in systems based on phase shift keyed modulation schemes, this assumption is not valid. Here we show the impact...... on accumulated spontaneous emission for a parametric amplifier operated in saturation....

  9. European Research on THz Vacuum Amplifiers

    DEFF Research Database (Denmark)

    Brunetti, F.; Cojocarua, C.-S.; de Rossi, A.

    2010-01-01

    The OPTHER (OPtically Driven TeraHertz AmplifiERs) project represents a considerable advancement in the field of high frequency amplification. The design and realization of a THz amplifier within this project is a consolidation of efforts at the international level from the main players of the Eu...

  10. low pump power photonic crystal fibre amplifiers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.; Broeng, Jes; Bjarklev, Anders Overgaard

    2003-01-01

    Designs of low pump power optical amplifiers, based on photonic crystal fibres are presented. The potential of these fibre amplifiers is investigated, and it is demonstrated that such amplifiers may deliver gains of more than 15 dB at 1550 nm with less than 1 mW of optical pump power....

  11. Cooled Low-Noise HEMT Microwave Amplifiers

    Science.gov (United States)

    Bautista, J. Javier; Ortiz, Gerardo G.; Duh, Kuanghann George

    1992-01-01

    Prototype cooled low-noise microwave amplifiers based on high-electron-mobility transistors (HEMT's) considered as replacements for cooled ruby masers used as low-noise receiver-front-end amplifiers in communications, radio science, radar systems, radio astronomy, and telemetry. HEMT amplifier operates at 12 K, requires less cooling power and operates at lower cost with simpler, more-reliable cooling system.

  12. Changes in chemical composition related to fungal infection and induced resistance in carnation and radish investigated by pyrolysis mass spectrometry

    NARCIS (Netherlands)

    Steijl, Harko; Niemann, G.J.; Boon, J.J.

    1999-01-01

    Pseudomonas fluorescens WCR 417r induces systemic resistance in radish roots challenged by Fusarium oxysporum f. sp. raphani and, incidentally, in carnation stems challenged by Fusarium oxysporum f. sp. dianthi. The induced systemic resistance is not associated with accumulation of

  13. From microchannels to nanochannels in a bilayer resist

    Science.gov (United States)

    Ocola, Leonidas E.; Stein, Aaron

    2005-01-01

    This paper describes the use of a unique combination of an environmentally stable chemically amplified photoresist (UV113, Shipley) and a copolymer of methyl styrene and chloromethyl acrylate P(MS/CMA) resist (ZEP520, Zeon), without any additional intermediate layers, in the fabrication of micro- and nanochannels. The two resists used are innocuous to each other during the designed process flow, providing flexibility, high resolution, greater throughput and ease of use. We have also determined that the maximum channel length is limited by diffusion and mass transport effects, and that sub-100 nm nanochannels can be obtained with 30 micron lengths.

  14. Physico-Chemical-Managed Killing of Penicillin-Resistant Static and Growing Gram-Positive and Gram-Negative Vegetative Bacteria

    Science.gov (United States)

    Richmond, Robert Chaffee (Inventor); Schramm, Jr., Harry F. (Inventor); Defalco, Francis G. (Inventor); Farris, III, Alex F. (Inventor)

    2012-01-01

    Systems and methods for the use of compounds from the Hofmeister series coupled with specific pH and temperature to provide rapid physico-chemical-managed killing of penicillin-resistant static and growing Gram-positive and Gram-negative vegetative bacteria. The systems and methods represent the more general physico-chemical enhancement of susceptibility for a wide range of pathological macromolecular targets to clinical management by establishing the reactivity of those targets to topically applied drugs or anti-toxins.

  15. Altered resistance to Trichinella spiralis infection following subchronic exposure of adult mice to chemicals of environmental concern

    Energy Technology Data Exchange (ETDEWEB)

    Luebke, R.W.

    1981-01-01

    The effects of subchronic chemical exposure on expulsion of adult Trichinella spiralis from the small intestine of mice and encystment of newborn larvae in the host's musculature were investigated. Exposure to diethylstilbestrol, benzo(a)pyrene, tris-(1,3-dichloro-2-propyl) phosphate, cyclophosphamide, phorbol myristate acetate, and dimethylvinylchloride prior to infection of mice with 200 infective larvae resulted in larger worm burdens in treated animals than in controls 14 days after infection. Worm expulsion was not affected by exposure to tris-(2,3-dibromopropyl)phosphate, orthophenylphenol, and indomethacin. Increased burdens of muscle-phase larvae were found in animals that maintained significant numbers of adult worms in the gut at 14 days, except in mice administered diethylstilbestrol and dimethylvinylchloride. Exposure to diethylstilbestrol and cyclophosphamide resulted in decreased inflammatory reactions in the tissues of the small intestine and development of bone marrow eosinophilia in infected mice. Marrow eosinophilia was likewise decreased in mice given tris-(1,3-dichloro-2-propyl)phosphate before infection. Additional studies with diethylstilbestrol administered either before, at the time of, or after infection showed inhibition of worm expulsion. Drug exposure during a primary infection inhibited the expulsion of a second T. spiralis infection, but did not affect worm elimination when given during a second infection. Treatment with diethylstilbestrol after artificial sensitization of mice with Trichinella antigens decreased delayed hypersensitivity responses to the sensitizing antigen. Immune functions, assessed by lymphoproliferative responses to mitogens and antibody responses to sheep red blood cells, generally correlated with altered host resistance to T. spiralis infection.

  16. Chemical conjugation of 2-hexadecynoic acid to C5-curcumin enhances its antibacterial activity against multi-drug resistant bacteria.

    Science.gov (United States)

    Sanabria-Ríos, David J; Rivera-Torres, Yaritza; Rosario, Joshua; Gutierrez, Ricardo; Torres-García, Yeireliz; Montano, Nashbly; Ortíz-Soto, Gabriela; Ríos-Olivares, Eddy; Rodríguez, José W; Carballeira, Néstor M

    2015-11-15

    The first total synthesis of a C5-curcumin-2-hexadecynoic acid (C5-Curc-2-HDA, 6) conjugate was successfully performed. Through a three-step synthetic route, conjugate 6 was obtained in 13% overall yield and tested for antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) strains. Our results revealed that 6 was active against eight MRSA strains at MICs that range between 31.3 and 62.5 μg/mL. It was found that the presence of 2-hexadecynoic acid (2-HDA, 4) in conjugate 6 increased 4-8-fold its antibacterial activity against MRSA strains supporting our hypothesis that the chemical connection of 4 to C5-curcumin (2) increases the antibacterial activity of 2 against Gram-positive bacteria. Combinational index (CIn) values that range between 1.6 and 2.3 were obtained when eight MRSA strains were treated with an equimolar mixture of 2 and 4. These results demonstrated that an antagonistic effect is taking place. Finally, it was investigated whether conjugate 6 can affect the replication process of S. aureus, since this compound inhibited the supercoiling activity of the S. aureus DNA gyrase at minimum inhibitory concentrations (MIC) of 250 μg/mL (IC50=100.2±13.9 μg/mL). Moreover, it was observed that the presence of 4 in conjugate 6 improves the anti-topoisomerase activity of 2 towards S. aureus DNA gyrase, which is in agreement with results obtained from antibacterial susceptibility tests involving MRSA strains. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. High temperature charge amplifier for geothermal applications

    Science.gov (United States)

    Lindblom, Scott C.; Maldonado, Frank J.; Henfling, Joseph A.

    2015-12-08

    An amplifier circuit in a multi-chip module includes a charge to voltage converter circuit, a voltage amplifier a low pass filter and a voltage to current converter. The charge to voltage converter receives a signal representing an electrical charge and generates a voltage signal proportional to the input signal. The voltage amplifier receives the voltage signal from the charge to voltage converter, then amplifies the voltage signal by the gain factor to output an amplified voltage signal. The lowpass filter passes low frequency components of the amplified voltage signal and attenuates frequency components greater than a cutoff frequency. The voltage to current converter receives the output signal of the lowpass filter and converts the output signal to a current output signal; wherein an amplifier circuit output is selectable between the output signal of the lowpass filter and the current output signal.

  18. Audio power amplifier design handbook

    CERN Document Server

    Self, Douglas

    2013-01-01

    This book is essential for audio power amplifier designers and engineers for one simple reason...it enables you as a professional to develop reliable, high-performance circuits. The Author Douglas Self covers the major issues of distortion and linearity, power supplies, overload, DC-protection and reactive loading. He also tackles unusual forms of compensation and distortion produced by capacitors and fuses. This completely updated fifth edition includes four NEW chapters including one on The XD Principle, invented by the author, and used by Cambridge Audio. Cro

  19. Visual information: amplifying and foraging

    Science.gov (United States)

    Knight, Claire; Munro, Malcolm

    2001-05-01

    Visualization is an important weapon in the management and control of the vast flood of data now generated. In order to be effective and useful it is important that such visualizations are designed to accommodate the variabilities of the tasks to which they will be put, and for the data they will be expected to be able to display. Such a view necessarily means that not all visualizations are always applicable. To this end, work has been done on visualizing software and systems with the aim of creating intelligence amplifying tools that aid, rather than try to replace the user and his intuition and domain knowledge.

  20. High power RF solid state power amplifier system

    Science.gov (United States)

    Sims, III, William Herbert (Inventor); Chavers, Donald Gregory (Inventor); Richeson, James J. (Inventor)

    2011-01-01

    A high power, high frequency, solid state power amplifier system includes a plurality of input multiple port splitters for receiving a high-frequency input and for dividing the input into a plurality of outputs and a plurality of solid state amplifier units. Each amplifier unit includes a plurality of amplifiers, and each amplifier is individually connected to one of the outputs of multiport splitters and produces a corresponding amplified output. A plurality of multiport combiners combine the amplified outputs of the amplifiers of each of the amplifier units to a combined output. Automatic level control protection circuitry protects the amplifiers and maintains a substantial constant amplifier power output.

  1. Temperature-stabilized differential amplifier for low-noise DC measurements

    Science.gov (United States)

    Märki, P.; Braem, B. A.; Ihn, T.

    2017-08-01

    A tabletop low-noise differential amplifier with a bandwidth of 100 kHz is presented. Low voltage drifts of the order of 100 nV/day are reached by thermally stabilizing relevant amplifier components. The input leakage current is below 100 fA. Input-stage errors are reduced by extensive circuitry. Voltage noise, current noise, input capacitance, and input current are extraordinarily low. The input resistance is larger than 1 T Ω . The amplifiers were tested with and deployed for electrical transport measurements of quantum devices at cryogenic temperatures.

  2. Inactivation of chemical and heat-resistant spores of Bacillus and Geobacillus by nitrogen cold atmospheric plasma and comparison to thermal and chemical based methods

    NARCIS (Netherlands)

    Bokhorst-van de Veen, van H.; Xie, H.; Esveld, D.C.; Abee, T.; Mastwijk, H.C.; Nierop Groot, M.N.

    2015-01-01

    Bacterial spores are resistant to severe conditions and form a challenge to eradicate from food or food packaging material. Cold atmospheric plasma (CAP) treatment is receiving more attention as potential sterilization method at relatively mild conditions but the exact mechanism of inactivation is

  3. Dynamic emergence of the mesenchymal CD44(pos)CD24(neg/low) phenotype in HER2-gene amplified breast cancer cells with de novo resistance to trastuzumab (Herceptin).

    Science.gov (United States)

    Oliveras-Ferraros, Cristina; Vazquez-Martin, Alejandro; Martin-Castillo, Begoña; Cufí, Silvia; Del Barco, Sonia; Lopez-Bonet, Eugeni; Brunet, Joan; Menendez, Javier A

    2010-06-18

    Evidence is mounting that the occurrence of the CD44(pos)/CD24(neg/low) cell population, which contains potential breast cancer (BC) stem cells, could explain BC clinical resistance to HER2-targeted therapies. We investigated whether de novo refractoriness to the anti-HER2 monoclonal antibody trastuzumab (Tzb; Herceptin) may relate to the dynamic regulation of the mesenchymal CD44(pos)/CD24(neg/low) phenotype in HER2-positive BC. We observed that the subpopulation of Tzb-refractory JIMT-1 BC cells exhibiting CD44(pos)/CD24(neg/low)-surface markers switched with time. Low-passage JIMT-1 cell cultures were found to spontaneously contain approximately 10% of cells bearing the CD44(pos)/CD24(neg/low) immunophenotype. Late-passage (>60) JIMT-1 cultures accumulated approximately 80% of CD44(pos)/CD24(neg/low) cells and closely resembled the CD44(pos)/CD24(neg/low)-enriched ( approximately 85%) cell population constitutively occurring in HER2-negative MDA-MB-231 mesenchymal BC cells. Dynamic expression of mesenchymal markers was not limited to CD44/CD24 because high-passages of JIMT-1 cells exhibited also reduced expression of the HER2 protein and over-secretion of pro-invasive/metastatic chemokines and metalloproteases. Accordingly, late-passage JIMT-1 cells displayed an exacerbated migratogenic phenotype in plastic, collagen, and fibronectin substrates. Intrinsic genetic plasticity to efficiently drive the emergence of the CD44(pos)/CD24(neg/low) mesenchymal phenotype may account for de novo resistance to HER2 targeting therapies in basal-like BC carrying HER2 gene amplification. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  4. Switched-capacitor amplifier and applications

    Science.gov (United States)

    Seki, H.; Yamamoto, M.; Mori, S.

    1985-01-01

    A switched-capacitor (SC) amplifier in which the bias and load circuits are made of SC circuits is proposed. It is shown that by changing the control clock in the SC circuit, which is suitable for integration, the characteristics of the amplifier can be varied. An SC amplifier of the signal-recursion type is described. Since the SC amplifier is configured with only one active device and one set of peripheral components, it has a small size and a high gain. An example is given for an SC bandpass filter using the SC amplifier. It is concluded that the SC amplifier is useful for integration and low-power consumption of the SC network.

  5. Differential automatic zero-adjusting amplifier.

    Science.gov (United States)

    Broersen, B; Van Krevelen, F; van Heusden, J T; van Heukelom, J S

    1979-07-01

    A method is described for building a low-voltage-drift differential dc amplifier featuring automatic zero adjustment, a high input impedance, and a bandwidth of 10 kHz. This is achieved by an asymmetric two-step process between the input signal and ground. Bandwidth can be extended by the use of a second amplifier during the ground-sampling time. The amplifier can be made with standard electronic components. A major advantage of this method is that an existing amplifier can easily be converted into a low-voltage-drift amplifier by adding the essential elements of the described automatic zero-adjusting amplifier to its input stage. To illustrate the method a practical example is constructed featuring a drift of 0.2 microV/ degrees C.

  6. Effect of chemical compositions and heat treatment on IGSCC resistance for strain hardened low carbon austenitic stainless steels in oxygenated water

    Energy Technology Data Exchange (ETDEWEB)

    Yonezawa, T. [FRRI, Graduate School of Engineering, Tohoku University (Japan); Kanasaki, H.; Fujimoto, K.; Taneike, M. [Takasago R-D Center, Mitsubishi Heavy Industries (Japan); Ooki, S.; Sueishi, Y.; Tezuka, H.; Takamori, K.; Suzuki, S. [Materials Engineering Center, R-D Center, Tokyo Electric Power Company (Japan)

    2011-07-01

    In order to develop the highly resistant alternative materials to intergranular stress corrosion cracking (IGSCC) for the non-sensitized and strain hardened low carbon austenitic stainless steel in oxygenated water, the effects of chemical compositions and heat treatment conditions on the IGSCC resistance and stacking fault energy (SFE) values were studied for 33 laboratory melted steels and commercial type 310S stainless steel. The IGSCC resistance for test materials was compared by the maximum crack length, average crack length and cracked area in fatigue pre-cracked CT specimens after SCC test in oxygenated high temperature water. SFE values for these test materials were measured by the transmission electron microscopy on the width of isolated extended dislocations under g-3g weak beam condition for thin foils taken from the test materials, in this study. From these experiments, the effects of the chromium, molybdenum, nitrogen, silicon and manganese contents on the SCC resistance for non-aged materials were not so pronounced in this study. It is strongly suggested that the SFE value is a key parameter for the IGSCC resistance of the aged or non-aged and strain hardened low carbon austenitic stainless steels. (authors)

  7. Corrosion resistance of amorphous hydrogenated SiC and diamond-like coatings deposited by r. f. -plasma-enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sella, C. (Lab. de Physique des Materiaux, CNRS, 92 Meudon (France)); Lecoeur, J. (Lab. d' Electrochimie Interfaciale, CNRS, 92 Meudon (France)); Sampeur, Y. (ICMC, 91 Le Coudray Montceaux (France)); Catania, P. (ICMC, 91 Le Coudray Montceaux (France))

    1993-10-08

    This paper reports on the properties and corrosion resistance of amorphous hydrogenated carbon and amorphous hydrogenated SiC films deposited by r.f.-plasma-enhanced chemical vapour deposition at low temperatures (below 200 C). SiC coatings were prepared from SiH[sub 4]-CH[sub 4] gas mixtures. Hydrogenated diamond-like coatings were deposited from classical CH[sub 4]-H[sub 2] mixtures. The influence of various deposition parameters was investigated. Microstructural and mechanical properties of the films were studied (density, hydrogen content, nanohardness, internal stress, critical load and friction coefficient). Two examples of corrosion resistance are given: (1) the corrosion resistance and biocompatibility of SiC and diamond-like coatings deposited on metal implants (Ti alloy) (the corrosion resistance is evaluated through potentiodynamic polarization tests in biological media; the biocompatibility of coated and uncoated metals is compared using differentiated human cell cultures); and (2) the corrosion resistance of SiC-coated magnesium in chloride-containing boric borate buffer at pH = 9.3 evaluated from anodic polarization curves and scanning electron microscopy studies. (orig.)

  8. Enhanced Gain in Photonic Crystal Amplifiers

    DEFF Research Database (Denmark)

    Ek, Sara; Semenova, Elizaveta; Hansen, Per Lunnemann

    2012-01-01

    We experimentally demonstrate enhanced gain in the slow-light regime of quantum well photonic crystal amplifiers. A strong gain enhancement is observed with the increase of the group refractive index, due to light slow-down. The slow light enhancement is shown in a amplified spontaneous emission ....... These results are promising for short and efficient semiconductor optical amplifiers. This effect will also benefit other devices, such as mode locked lasers....

  9. Short Rayleigh Range Free Electron Laser Amplifiers

    CERN Document Server

    Yu, L H; Murphy, J B; Rose, J; Shaftan, T V; Wang, X J; Watanabe, T

    2005-01-01

    An important requirement for a high average power laser system is a manageable power density on the first optical element. One possibility to achieve this is a single pass amplifier which generates a short Rayleigh range (SRL) light beam. We present design parameters and calculated performances for several SRL configurations. These include a simulation of the optically guided (pinched) MW class FEL [1], the scalloped beam FEL amplifier [2] and high gain TOK amplifiers we propose to explore at our SDL facility.

  10. Silicon Germanium Cryogenic Low Noise Amplifiers

    Science.gov (United States)

    Bardin, J. C.; Montazeri, S.; Chang, Su-Wei

    2017-05-01

    Silicon germanium heterojunction bipolar transistors have emerged in the last decade as an excellent option for use in cryogenic low noise amplifiers. This paper begins with a review of the critical developments that have led to today’s cryogenic low noise amplifiers. Next, recent work focused on minimizing the power consumption of SiGe cryogenic amplifiers is presented. Finally, open issues related to the cryogenic noise properties of SiGe HBTs are discussed.

  11. Transverse pumped laser amplifier architecture

    Science.gov (United States)

    Bayramian, Andrew James; Manes, Kenneth; Deri, Robert; Erlandson, Al; Caird, John; Spaeth, Mary

    2013-07-09

    An optical gain architecture includes a pump source and a pump aperture. The architecture also includes a gain region including a gain element operable to amplify light at a laser wavelength. The gain region is characterized by a first side intersecting an optical path, a second side opposing the first side, a third side adjacent the first and second sides, and a fourth side opposing the third side. The architecture further includes a dichroic section disposed between the pump aperture and the first side of the gain region. The dichroic section is characterized by low reflectance at a pump wavelength and high reflectance at the laser wavelength. The architecture additionally includes a first cladding section proximate to the third side of the gain region and a second cladding section proximate to the fourth side of the gain region.

  12. Characterization of Josephson parametric amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Pogorzalek, Stefan; Fedorov, Kirill; Zhong, Ling; Bitzenbichler, Martin; Haeberlein, Max; Schwarz, Manuel J.; Eder, Peter; Goetz, Jan; Wulschner, Friedrich; Xie, Edwar; Baust, Alexander; Marx, Achim; Menzel, Edwin P.; Deppe, Frank; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany)

    2015-07-01

    Propagating quantum microwaves are a promising building block for quantum communication. In particular, such itinerant quantum microwaves can be generated in the form of squeezed photon states using Josephson parametric amplifiers (JPA). A thorough experimental characterization of JPAs is therefore an essential prerequisite for further experiments towards quantum communication. For implementing JPAs we employ an established λ/4 bi-coplanar microwave resonator design where a dc-SQUID is biased by an external flux to tune the resonant frequency. An inductively coupled antenna acts as a pump for the JPA. We characterize several JPAs and evaluate the data within standard Josephson junction theory and the input-output formalism. In particular, we investigate hysteretic and bifurcation behavior of the JPAs in addition to usual non-degenerate JPA gain measurements.

  13. Input Impedance of the Microstrip SQUID Amplifier

    Science.gov (United States)

    Kinion, Darin; Clarke, John

    2008-03-01

    We present measurements of the complex scattering parameters of microstrip SQUID amplifiers (MSA) cooled to 4.2 K. The input of the MSA is a microstrip transmission line in the shape of a square spiral coil surrounding the hole in the SQUID washer that serves as the ground plane. The input impedance is found by measuring the reverse scattering parameter (S11) and is described well by a low-loss transmission line model. We map the low-loss transmission line model into an equivalent parallel RLC circuit in which a resistance R, inductance L, and capacitance C are calculated from the resonant frequency, characteristic impedance and attenuation factor. Using this equivalent RLC circuit, we model the MSA and input network with a lumped circuit model that accurately predicts the observed gain given by the forward scattering parameter (S21). We will summarize results for different coil geometries and terminations as well as SQUID bias conditions. A portion of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344 and by Lawrence Berkeley National Laboratory under Contract No. DE-AC02-05CH11231.

  14. Design of an 1800nm Raman amplifier

    DEFF Research Database (Denmark)

    Svane, Ask Sebastian; Rottwitt, Karsten

    2013-01-01

    in transmission loss, but also the reduction in the Raman gain coefficient as the amplifier wavelength is increased. Both polarization components of the Raman gain is characterized, initially for linearly co-polarized signal and pump, subsequently linearly polarized orthogonal signal and pump. The noise......We present the experimental results for a Raman amplifier that operates at 1810 nm and is pumped by a Raman fiber laser at 1680 nm. Both the pump laser and the Raman amplifier is polarization maintaining. A challenge when scaling Raman amplifiers to longer wavelengths is the increase...

  15. Physical and Chemical Barriers in Root Tissues Contribute to Quantitative Resistance to Fusarium oxysporum f. sp. pisi in Pea

    Directory of Open Access Journals (Sweden)

    Moustafa Bani

    2018-02-01

    Full Text Available Fusarium wilt caused by Fusarium oxysporum f. sp. pisi (Fop is one of the most destructive diseases of pea worldwide. Control of this disease is difficult and it is mainly based on the use of resistant cultivars. While monogenic resistance has been successfully used in the field, it is at risk of breakdown by the constant evolution of the pathogen. New sources of quantitative resistance have been recently identified from a wild relative Pisum spp. collection. Here, we characterize histologically the resistance mechanisms occurring in these sources of quantitative resistance. Detailed comparison, of the reaction at cellular level, of eight pea accessions with differential responses to Fop race 2, showed that resistant accessions established several barriers at the epidermis, exodermis, cortex, endodermis and vascular stele efficiently impeding fungal progression. The main components of these different barriers were carbohydrates and phenolic compounds including lignin. We found that these barriers were mainly based on three defense mechanisms including cell wall strengthening, formation of papilla-like structures at penetration sites and accumulation of different substances within and between cells. These defense reactions varied in intensity and localization between resistant accessions. Our results also clarify some steps of the infection process of F. oxysporum in plant and support the important role of cell wall-degrading enzymes in F. oxysporum pathogenicity.

  16. Ping-pong auto-zero amplifier with glitch reduction

    Science.gov (United States)

    Larson, Mark R [Maple Grove, MN

    2008-01-22

    A ping-pong amplifier with reduced glitching is described. The ping-pong amplifier includes a nulling amplifier coupled to a switching network. The switching network is used to auto-zero a ping amplifier within a ping-pong amplifier. The nulling amplifier drives the output of a ping amplifier to a proper output voltage level during auto-zeroing of the ping amplifier. By being at a proper output voltage level, glitches associated with transitioning between a ping amplifier and a pong amplifier are reduced or eliminated.

  17. Chemical Ablation of Gastric Inhibitory Polypeptide Receptor Action by Daily (Pro3)GIP Administration Improves Glucose Tolerance and Ameliorates Insulin Resistance and Abnormalities of Islet Structure in Obesity-Related Diabetes

    National Research Council Canada - National Science Library

    Victor A. Gault; Nigel Irwin; Brian D. Green; Jane T. McCluskey; Brett Greer; Clifford J. Bailey; Patrick Harriott; Finbarr P.M. O’Harte; Peter R. Flatt

    2005-01-01

    Chemical Ablation of Gastric Inhibitory Polypeptide Receptor Action by Daily (Pro 3 )GIP Administration Improves Glucose Tolerance and Ameliorates Insulin Resistance and Abnormalities of Islet Structure in Obesity-Related Diabetes Victor...

  18. Planar waveguide amplifiers and laser in erbium doped silica

    DEFF Research Database (Denmark)

    Guldberg-Kjær, Søren Andreas; Kristensen, Martin

    1999-01-01

    The objective of this work was to develop optically amplifying planar waveguides, using erbium-doped germano-silicate glass films deposited by PECVD (Plasma Enhanced Chemical Vapour Deposition). The waveguides should exhibit enough gain to be useful as optical amplifiers in integrated planar...... lightwave circuits, as well as provide the gain medium for integrated planar waveguide lasers. The work and the obtained results are presented in this thesis: The manufacturing of silica thin films is described and it is shown that the refractive index o fthe films can be controlled by germanium co......-doping. the method used for co-doping thin films with erbium and aluminium is described and it is shown that the erbium concentration as well as the relative erbium/aluminium content can be controlled with good precision. The incorporated erbium ions are excited using light of 980 nm wavelength and the optical...

  19. Self-pulsation in Raman fiber amplifiers

    DEFF Research Database (Denmark)

    Pedersen, Martin Erland Vestergaard; Ott, Johan Raunkjær; Rottwitt, Karsten

    2009-01-01

    Dynamic behavior caused by Brillouin scattering in Raman fiber amplifiers is studied. Modes of self-pulsation steady state oscillations are found. Their dependence on amplification scheme is demonstrated.......Dynamic behavior caused by Brillouin scattering in Raman fiber amplifiers is studied. Modes of self-pulsation steady state oscillations are found. Their dependence on amplification scheme is demonstrated....

  20. CMOS Current-mode Operational Amplifier

    DEFF Research Database (Denmark)

    Kaulberg, Thomas

    1992-01-01

    A fully differential-input differential-output current-mode operational amplifier (COA) is described. The amplifier utilizes three second generation current-conveyors (CCII) as the basic building blocks. It can be configured to provide either a constant gain-bandwidth product in a fully balanced...

  1. A CMOS current-mode operational amplifier

    DEFF Research Database (Denmark)

    Kaulberg, Thomas

    1993-01-01

    A fully differential-input, differential-output, current-mode operational amplifier (COA) is described. The amplifier utilizes three second-generation current conveyors (CCIIs) as the basic building blocks. It can be configured to provide either a constant gain-bandwidth product in a fully balanced...

  2. The inhibition of methicillin-resistant Staphylococcus aureus by essential oils isolated from leaves and fruits of Schinus areira depending on their chemical compositions.

    Science.gov (United States)

    Celaya, Liliana S; Alabrudzińska, Marta H; Molina, Ana C; Viturro, Carmen I; Moreno, Silvia

    2014-01-01

    Schinus areira L. is a native plant from South America used for centuries in traditional medicine. Here, we investigate the antimicrobial activity of four essential oils extracted from leaves and fruits of S. areira exhibiting different chemical profiles. The antibacterial activity against the human pathogenic bacteria Staphylococcus aureus susceptible as well as methicillin resistant strain was assessed by the broth microdilution assay. The results showed that the limonene-rich oil extracted from the leaves and fruits have potent antibacterial effect on S. aureus ATCC 25923, while the α-phellandrene-rich fruit oil having a lower content of limonene showed the lowest antibacterial efficacy. In this work, for the first time, we demonstrated the bactericidal activity of essential oils isolated from fruits and leaves of S. areira against susceptible and methicillin resistant S. aureus strains. All results point out the potential use of the S. areira oils as antimicrobial agents to be used, at least against Staphylococcal infections.

  3. Re-engineering nalidixic acid's chemical scaffold: A step towards the development of novel anti-tubercular and anti-bacterial leads for resistant pathogens.

    Science.gov (United States)

    Peraman, Ramalingam; Varma, Raghu Veer; Reddy, Y Padmanabha

    2015-10-01

    Occurrence of antibacterial and antimycobacterial resistance stimulated a thrust to discover new drugs for infectious diseases. Herein we report the work on re-engineering nalidixic acid's chemical scaffold for newer leads. Stepwise clubbing of quinoxaline, 1,2,4-triazole/1,3,4-oxadiazole with nalidixic acid yielded better compounds. Compounds were screened against ciprofloxacin resistant bacteria and Mycobacterium tuberculosis H37Rv species. Results were obtained as minimum inhibitory concentration, it was evident that molecule with quinoxaline linked azide as side chain served as antitubercular lead (<6.25 μg/ml) whilst molecule with oxadiazole or triazole linked quinoxaline side chain served as anti-bacterial lead. Few compounds were significantly active against Escherichia coli and Proteus vulgaris with MIC less than 0.06 μg/ml and relatively potent than ciprofloxacin. No true compound was potentially active against Salmonella species as compared to amoxicillin. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Design and performance of the beamlet amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Erlandson, A.C.; Rotter, M.D.; Frank, M.D.; McCracken, R.W.

    1996-06-01

    In future laser systems, such as the National Ignition Facility (NIF), multi-segment amplifiers (MSAs) will be used to amplify the laser beam to the required levels. As a prototype of such a laser architecture, the authors have designed, built, and tested flash-lamp-pumped, Nd:Glass, Brewster-angle slab MSAs for the Beamlet project. In this article, they review the fundamentals of Nd:Glass amplifiers, describe the MSA geometry, discuss parameters that are important in amplifier design, and present our results on the characterization of the Beamlet MSAs. In particular, gain and beam steering measurements show that the Beamlet amplifiers meet all optical performance specifications and perform close to model predictions.

  5. An Implantable CMOS Amplifier for Nerve Signals

    DEFF Research Database (Denmark)

    Nielsen, Jannik Hammel; Lehmann, Torsten

    2001-01-01

    In this paper, a low noise high gain CMOS amplifier for minute nerve signals is presented. By using a mixture of weak- and strong inversion transistors, optimal noise suppression in the amplifier is achieved. A continuous-time offset-compensation technique is utilized in order to minimize impact...... on the amplifier input nodes. The method for signal recovery from noisy nerve signals is presented. A prototype amplifier is realized in a standard digital 0.5 μm CMOS single poly, n-well process. The prototype amplifier features a gain of 80 dB over a 3.6 kHz bandwidth, a CMRR of more than 87 dB and a PSRR...

  6. Detection of Non-Amplified Genomic DNA

    CERN Document Server

    Corradini, Roberto

    2012-01-01

    This book offers a state-of-the-art overview on non amplified DNA detection methods and provides chemists, biochemists, biotechnologists and material scientists with an introduction to these methods. In fact all these fields have dedicated resources to the problem of nucleic acid detection, each contributing with their own specific methods and concepts. This book will explain the basic principles of the different non amplified DNA detection methods available, highlighting their respective advantages and limitations. The importance of non-amplified DNA sequencing technologies will be also discussed. Non-amplified DNA detection can be achieved by adopting different techniques. Such techniques have allowed the commercialization of innovative platforms for DNA detection that are expected to break into the DNA diagnostics market. The enhanced sensitivity required for the detection of non amplified genomic DNA has prompted new strategies that can achieve ultrasensitivity by combining specific materials with specifi...

  7. Calculations of superconducting parametric amplifiers performances

    Science.gov (United States)

    Goto, T.; Takeda, M.; Saito, S.; Shimakage, H.

    2017-07-01

    A superconducting parametric amplifier is an electromagnetic wave amplifier with high-quality characteristics such as a wide bandwidth, an extremely low noise, and a high dynamic range. In this paper, we report on the estimations of a YBCO superconducting parametric amplifier characteristic. The YBCO thin films were deposited on an MgO substrate by a pulsed laser deposition method. Based on the measured YBCO thin film parameters, theoretical calculations were implemented for evaluations of kinetic inductance nonlinearities and parametric gains. The nonlinearity of the YBCO thin film was estimated to be stronger than a single crystal NbTiN thin film. It is indicated that the YBCO parametric amplifier has a potential to be realized the amplifier with the high parametric gain. It is also expected that it could be operated in the range of the high frequency band, at the high temperature, and low applied current.

  8. Design of an 1800 nm Raman Amplifier

    DEFF Research Database (Denmark)

    Svane, Ask Sebastian; Rottwitt, Karsten

    in the pump power requirement and deteriorated noise properties. Here we demonstrate a Raman amplifier designed for signal wavelengths around 1800 nm. The amplification fiber is an OFS PM Raman fiber, and is pumped by a Raman fiber laser emitting at 1680 nm [4]. The amplifier was pumped co...... suggested as potential transmission fibers for extended wavelength operation, as low losses at long wavelengths have been predicted [3]. Fig. 1 illustrates the predicted low loss limit for a hollow core fiber and for comparison the measured loss of a OFS True Wave fiber. Besides low loss transmission fibers......, also extended band amplifiers are required. As a solution to the latter challenge, Raman amplifiers are suggested as promising candidates. The main hurdle when designing a long wavelength Raman amplifier is the increased intrinsic fiber attenuation which as a consequence leads to an increase...

  9. Quantum dots: lasers and amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Bimberg, Dieter; Ledentsov, Nikolai [Institut fuer Festkoerperphysik, PN5-2, Technische Universitaet Berlin, Hardenbergstrasse 36, 10623 (Germany)

    2003-06-25

    Continuous wave room-temperature output power of {approx} 3 W for edge emitters and of 1.2 mW for vertical-cavity surface-emitting lasers is realized for GaAs-based devices using InAs quantum dots (QDs) operating at 1.3 {mu}m. Characteristic temperatures up to 170 K below 330 K are realized. Simultaneously, differential efficiency exceeds 80% for these devices. Lasers emitting up to 12 W at 1140-1160 nm are useful as pump sources for Tm{sup 3+}-doped fibres for frequency up-conversion to 470 nm. Both types of lasers show transparency current densities of 6 A cm{sup -2} per dot layer, {eta}{sub int} = 98% and {alpha}{sub i} around 1.5 cm{sup -1}. Long operation lifetimes (above 3000 h at 50 deg C heatsink temperature at 1.5 W CW) and improved radiation hardness as compared to quantum well (QW) devices are manifested. Cut-off frequencies of about 10 GHz at 1100 nm and 6 GHz at 1300 nm and low {alpha} factors resulting in reduced filamentation and improved M{sup 2} values in single-mode operation are realized. Quantum dot semiconductor optical amplifiers (QD SOAs) demonstrate gain recovery times of 120-140 fs, 4-7 times faster than bulk/QW SOAs. The breakthrough became possible due to the development of self-organized growth in QD technology. (topical review)

  10. Free electron maser amplifier experiments

    CERN Document Server

    Whyte, C G; Cross, A W; He, W; Ronald, K; Young, A; Phelps, A D R

    2000-01-01

    We present results from the X-band reversed guide magnetic field Raman Free Electron Maser (FEM) amplifier experiment at Strathclyde University. The FEM has been designed for zero slippage to achieve maximum instantaneous bandwidth. The tuneablity is further extended by the adjustment of beam voltage and undulator field strength. A 1 kW TWT has been used as the input source for broadband measurements and two 25 kW magnetrons for saturated output power measurements at discrete frequencies. Results show an instantaneous -3 dB bandwidth of 30% for a fixed cathode voltage and magnetic field. The device can be tuned over a range of 65% of the centre frequency by adjusting the cathode voltage. A saturated power of over 1 MW has been measured for 50 A input current. Broadband unsaturated gains of over 35 dB have been measured. An experiment using a 50 A beam from a thermionic cathode electron gun designed at Strathclyde is currently in progress. This will theoretically allow CW operation of the FEM using a DC undula...

  11. Measuring Optimal Length of the Amplifying Fiber in Different Working Conditions of the Amplifier

    Directory of Open Access Journals (Sweden)

    Radek Poboril

    2014-01-01

    Full Text Available The aim of this article is to highlight possible unwanted behaviour of an EDFA optical amplifier during temperature changes. After a brief introduction dealing with amplifiers and doped fibers in general we focus on the assembly of our own EDFA amplifier with standard construction and the IsoGain I-6 amplifying fiber, and on the parameters of its individual components. Since an erbium doped fiber has usually no direct thermal stabilization, temperature changes can affect performance of the entire amplifier. The next part of the article therefore describes the impacts of such changes on behaviour of our amplifier. At the very end we performed a measurement of the amplifier deployed in the actual WDM-PON the description of which can be found in the last chapter.

  12. An Implantable CMOS Amplifier for Nerve Signals

    DEFF Research Database (Denmark)

    Nielsen, Jannik Hammel; Lehmann, Torsten

    2003-01-01

    In this paper, a low noise high gain CMOS amplifier for minute nerve signals is presented. The amplifier is constructed in a fully differential topology to maximize noise rejection. By using a mixture of weak- and strong inversion transistors, optimal noise suppression in the amplifier is achieved....... A continuous-time current-steering offset-compensation technique is utilized in order to minimize the noise contribution and to minimize dynamic impact on the amplifier input nodes. The method for signal recovery from noisy nerve signals is presented. A prototype amplifier is realized in a standard digital 0.......5 mum CMOS single poly, n-well process. The prototype amplifier features a gain of 80 dB over a 10 kHz bandwidth, a CMRR of more than 87 dB and a PSRR greater than 84 dB. The equivalent input referred noise in the bandwidth of interest is 4.8 nV/rootHz. The amplifier power consumption is 275 muW, drawn...

  13. A Low-Noise Semiconductor Optical Amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Ratowsky, R.P.; Dijaili, S.; Kallman, J.S.; Feit, M.D.; Walker, J.

    1999-03-23

    Optical amplifiers are essential devices for optical networks, optical systems, and computer communications. These amplifiers compensate for the inevitable optical loss in long-distance propagation (>50 km) or splitting (>10x). Fiber amplifiers such as the erbium-doped fiber amplifier have revolutionized the fiber-optics industry and are enjoying widespread use. Semiconductor optical amplifiers (SOAs) are an alternative technology that complements the fiber amplifiers in cost and performance. One obstacle to the widespread use of SOAs is the severity of the inevitable noise output resulting from amplified spontaneous emission (ASE). Spectral filtering is often used to reduce ASE noise, but this constrains the source spectrally, and improvement is typically limited to about 10 dB. The extra components also add cost and complexity to the final assembly. The goal of this project was to analyze, design, and take significant steps toward the realization of an innovative, low-noise SOA based on the concept of ''distributed spatial filtering'' (DSF). In DSF, we alternate active SOA segments with passive free-space diffraction regions. Since spontaneous emission radiates equally in all directions, the free-space region lengthens the amplifier for a given length of gain region, narrowing the solid angle into which the spontaneous emission is amplified [1,2]. Our innovation is to use spatial filtering in a differential manner across many segments, thereby enhancing the effect when wave-optical effects are included [3]. The structure quickly and effectively strips the ASE into the higher-order modes, quenching the ASE gain relative to the signal.

  14. Hot-Roll-Pressing Mediated Transfer of Chemical Vapor Deposition Graphene for Transparent and Flexible Touch Screen with Low Sheet-Resistance.

    Science.gov (United States)

    Guo, Chengkun; Kong, Xianghua; Ji, Hengxing

    2018-06-01

    Obstacles associated with graphene as transparent conductive films mainly consist of the difficulties in high-quality graphene synthesis, efficient transfer and doping of samples with lateral size of tens of centimeters for practical applications. Herein we demonstrate a hot-roll-pressing transfer technique followed by wet-chemical doping of large area graphene film grown on copper foil by chemical vapor deposition (CVD). This method enabled cost-effective and ultraclean transfer of single-layer graphene with an arbitrary size onto transparent ethylene vinyl acetate/polyethylene terephthalate (EVA/PET) substrate without any polymer residues. The sheet resistance of the single-layer graphene covered EVA/PET (graphene/EVA/PET) reached 200 Ω/sq with optical transparency of 87.3%. The graphene/EVA/PET film can be bent over 10000 cycles at a radius of 2 mm with ∼0.02% increase in sheet resistance, showing excellent mechanical flexibility for bendable electronics which was demonstrated by a capacitive-type touch screen based on the graphene/EVA/PET transparent conducting film.

  15. Broad-band semiconductor optical amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Ding Ying [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)]. E-mail: yingding@red.semi.ac.cn; Kan Qiang [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Wang Junling [Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044 (China); Pan Jiaoqing [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Zhou Fan [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Chen Weixi [School of Physics, Peking University, Beijing 100871 (China); Wang Wei [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2007-01-15

    Broad-band semiconductor optical amplifiers (SOAs) with different thicknesses and thin bulk tensile-strained active layers were fabricated and studied. Amplified spontaneous emission (ASE) spectra and gain spectra of SOAs were measured and analyzed at different CW biases. A maximal 3 dB ASE bandwidth of 136 nm ranging from 1480 to 1616 nm, and a 3 dB optical amplifier gain bandwidth of about 90 nm ranging from 1510 to 1600 nm, were obtained for the very thin bulk active SOA. Other SOAs characteristics such as saturation output power and polarization sensitivity were measured and compared.

  16. A parallel input composite transimpedance amplifier

    Science.gov (United States)

    Kim, D. J.; Kim, C.

    2018-01-01

    A new approach to high performance current to voltage preamplifier design is presented. The design using multiple operational amplifiers (op-amps) has a parasitic capacitance compensation network and a composite amplifier topology for fast, precision, and low noise performance. The input stage consisting of a parallel linked JFET op-amps and a high-speed bipolar junction transistor (BJT) gain stage driving the output in the composite amplifier topology, cooperating with the capacitance compensation feedback network, ensures wide bandwidth stability in the presence of input capacitance above 40 nF. The design is ideal for any two-probe measurement, including high impedance transport and scanning tunneling microscopy measurements.

  17. Fundamentals of RF and microwave transistor amplifiers

    CERN Document Server

    Bahl, Inder J

    2009-01-01

    A Comprehensive and Up-to-Date Treatment of RF and Microwave Transistor Amplifiers This book provides state-of-the-art coverage of RF and microwave transistor amplifiers, including low-noise, narrowband, broadband, linear, high-power, high-efficiency, and high-voltage. Topics covered include modeling, analysis, design, packaging, and thermal and fabrication considerations. Through a unique integration of theory and practice, readers will learn to solve amplifier-related design problems ranging from matching networks to biasing and stability. More than 240 problems are included to help read

  18. Laser Cooled High-Power Fiber Amplifier

    OpenAIRE

    Nemova, Galina

    2009-01-01

    A theoretical model for laser cooled continuous-wave fiber amplifier is presented. The amplification process takes place in the Tm3+-doped core of the fluoride ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) glass fiber. The cooling process takes place in the Yb3+:ZBLAN fiber cladding. It is shown that for each value of the pump power and the amplified signal there is a distribution of the concentration of the Tm3+ along the length of the fiber amplifier, which provides its athermal operation. The influence ...

  19. Phase noise in RF and microwave amplifiers.

    Science.gov (United States)

    Boudot, Rodolphe; Rubiola, Enrico

    2012-12-01

    Understanding amplifier phase noise is a critical issue in many fields of engineering and physics, such as oscillators, frequency synthesis, telecommunication, radar, and spectroscopy; in the emerging domain of microwave photonics; and in exotic fields, such as radio astronomy, particle accelerators, etc. Focusing on the two main types of base noise in amplifiers, white and flicker, the power spectral density of the random phase φ(t) is Sφ(f) = b(0) + b(-1)/f. White phase noise results from adding white noise to the RF spectrum in the carrier region. For a given RF noise level, b(0) is proportional to the reciprocal of the carrier power P(0). By contrast, flicker results from a near-dc 1/f noise-present in all electronic devices-which modulates the carrier through some parametric effect in the semiconductor. Thus, b(-1) is a parameter of the amplifier, constant in a wide range of P(0). The consequences are the following: Connecting m equal amplifiers in parallel, b(-1) is 1/m times that of one device. Cascading m equal amplifiers, b(-1) is m times that of one amplifier. Recirculating the signal in an amplifier so that the gain increases by a power of m (a factor of m in decibels) as a result of positive feedback (regeneration), we find that b(-1) is m(2) times that of the amplifier alone. The feedforward amplifier exhibits extremely low b(-1) because the carrier is ideally nulled at the input of its internal error amplifier. Starting with an extensive review of the literature, this article introduces a system-oriented model which describes the phase flickering. Several amplifier architectures (cascaded, parallel, etc.) are analyzed systematically, deriving the phase noise from the general model. There follow numerous measurements of amplifiers using different technologies, including some old samples, and in a wide frequency range (HF to microwaves), which validate the theory. In turn, theory and results provide design guidelines and give suggestions for CAD and

  20. Ultrashort pulse amplification in cryogenically cooled amplifiers

    Science.gov (United States)

    Backus, Sterling J.; Kapteyn, Henry C.; Murnane, Margaret Mary

    2004-10-12

    A laser amplifier system amplifies pulses in a single "stage" from .about.10.sup.-9 joules to more than 10.sup.-3 joules, with average power of 1-10 watts, and beam quality M.sup.2 characteristics of the medium. This is done with the medium inside a sealed, evacuated or purged cell to avoid moisture or other materials condensing on the surface. A "seed" pulse from a separate laser is passed through the laser medium, one or more times, in any of a variety of configurations including single-pass, multiple-pass, and regenerative amplifier configurations.

  1. Small signal microwave amplifier design solutions

    CERN Document Server

    Grosch, Theodore

    2000-01-01

    This book explains techniques and examples for designing stable amplifiers for high-frequency applications in which the signal is small and the amplifier circuit is linear. An in-depth discussion of linear network theory provides the foundation needed to develop actual designs. Examples throughout the book will show you how to apply the knowledge gained in each chapter leading to the complex design of low noise amplifiers. Many exercises at the end of each chapter will help students to practice their skills. The solutions to these design problems are available in an accompanying solutions book

  2. Noise Suppression Phenomenon in Fiber Raman Amplifier

    Directory of Open Access Journals (Sweden)

    Felinskyi Georgii

    2015-06-01

    Full Text Available The problem of small bit error rate is actual in fiber Raman amplifiers. Our experimental data on the amplified spontaneous emission (ASE with backward pumping as a base of optical noise evaluation are presented in this paper. Raman gain spectrum for useful Stokes low-powered signal is calculated and compared with obtained spectrum of non-coherent ASE noise. It is shown that output optical signal has better gain than the amplified spontaneous emission that leads to appreciable growth of output optical signal-to-noise ratio.

  3. Noiseless attenuation using an optical parametric amplifier

    Science.gov (United States)

    Brewster, R. A.; Nodurft, I. C.; Pittman, T. B.; Franson, J. D.

    2017-10-01

    The process of heralded noiseless amplification, and the inverse process of heralded noiseless attenuation, have potential applications in the context of quantum communications. Although several different physical implementations of heralded noiseless amplifiers have now been demonstrated, the research on heralded noiseless attenuators has been largely confined to a beam-splitter based approach. Here we show that an optical parametric amplifier (OPA), combined with appropriate heralding, can also serve as a heralded noiseless attenuator. The counterintuitive use of an optical amplifier as an attenuator is only possible due to the probabilistic nature of the device.

  4. Corrosion resistant coatings (Al@#2@#O@#3@#) produced by metal-organic chemical vapour deposition using ATSB

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van Corbach, H.D.; Fransen, T.; Gellings, P.J.

    1993-01-01

    The metal organic chemical vapour deposition (MOCVD) of amorphous alumina films on steel was performed in nitrogen at atmospheric pressure. This MOCVD process is based on the thermal decomposition of aluminium-tri-sec-butoxide (ATSB). The effect of the deposition temperature (within the range

  5. The role of operating parameters and oxidative damage mechanisms of advanced chemical oxidation processes in the combat against antibiotic-resistant bacteria and resistance genes present in urban wastewater.

    Science.gov (United States)

    Michael-Kordatou, I; Karaolia, P; Fatta-Kassinos, D

    2017-10-27

    An upsurge in the study of antibiotic resistance in the environment has been observed in the last decade. Nowadays, it is becoming increasingly clear that urban wastewater is a key source of antibiotic resistance determinants, i.e. antibiotic-resistant bacteria and antibiotic resistance genes (ARB&ARGs). Urban wastewater reuse has arisen as an important component of water resources management in the European Union and worldwide to address prolonged water scarcity issues. Especially, biological wastewater treatment processes (i.e. conventional activated sludge), which are widely applied in urban wastewater treatment plants, have been shown to provide an ideal environment for the evolution and spread of antibiotic resistance. The ability of advanced chemical oxidation processes (AOPs), e.g. light-driven oxidation in the presence of H2O2, ozonation, homogeneous and heterogeneous photocatalysis, to inactivate ARB and remove ARGs in wastewater effluents has not been yet evaluated through a systematic and integrated approach. Consequently, this review seeks to provide an extensive and critical appraisal on the assessment of the efficiency of these processes in inactivating ARB and removing ARGs in wastewater effluents, based on recent available scientific literature. It tries to elucidate how the key operating conditions may affect the process efficiency, while pinpointing potential areas for further research and major knowledge gaps which need to be addressed. Also, this review aims at shedding light on the main oxidative damage pathways involved in the inactivation of ARB and removal of ARGs by these processes. In general, the lack and/or heterogeneity of the available scientific data, as well as the different methodological approaches applied in the various studies, make difficult the accurate evaluation of the efficiency of the processes applied. Besides the operating conditions, the variable behavior observed by the various examined genetic constituents of the

  6. A fast shaping amplifier-comparator integrated circuit for silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Barberis, E.; Cartiglia, N.; Dorfan, D.E.; Rahn, J.; Spencer, E.N.; Wilder, M. (Univ. of California, Santa Cruz, CA (United States). Santa Cruz Inst. for Particle Physics)

    1993-08-01

    The use of silicon strip detectors at hadron colliders with high collision rates, such as HERA, Fermi Collider Upgrade, and the SSC, presents five stringent requirements for its front-end electronics system. The circuitry must have microminiature size, very low power, fast shaping, near optimum noise, and radiation resistance. The authors describe a 64 channel amplifier-comparator for silicon strip detector fabricated on Tektronix SHPi bipolar process. This device is particularly useful in high rate colliders with silicon strip vertex detection. The design requirements include near optimum noise performance, very low power use, proton radiation resistance, and microminiature size. Additionally, the detector and amplifier can be DC coupled, since the amplifier is capable of absorbing increasing detector leakage current under irradiation. Circuit measurements show that the circuit will perform properly in its expected environment.

  7. Insight into the effect of inhibitor resistant S130G mutant on physico-chemical properties of SHV type beta-lactamase: a molecular dynamics study.

    Directory of Open Access Journals (Sweden)

    Mohd Hassan Baig

    Full Text Available Bacterial resistance is a serious threat to human health. The production of β-lactamase, which inactivates β-lactams is most common cause of resistance to the β-lactam antibiotics. The Class A enzymes are most frequently encountered among the four β-lactamases in the clinic isolates. Mutations in class A β-lactamases play a crucial role in substrate and inhibitor specificity. SHV and TEM type are known to be most common class A β-lactamases. In the present study, we have analyzed the effect of inhibitor resistant S130G point mutation of SHV type Class-A β-lactamase using molecular dynamics and other in silico approaches. Our study involved the use of different in silico methods to investigate the affect of S130G point mutation on the major physico-chemical properties of SHV type class A β-lactamase. We have used molecular dynamics approach to compare the dynamic behaviour of native and S130G mutant form of SHV β-lactamase by analyzing different properties like root mean square deviation (RMSD, H-bond, Radius of gyration (Rg and RMS fluctuation of mutation. The results clearly suggest notable loss in the stability of S130G mutant that may further lead to decrease in substrate specificity of SHV. Molecular docking further indicates that S130G mutation decreases the binding affinity of all the three inhibitors in clinical practice.

  8. Chemical and cytotoxic analyses of brown Brazilian propolis (Apis mellifera) and its in vitro activity against itraconazole-resistant Sporothrix brasiliensis.

    Science.gov (United States)

    Waller, Stefanie B; Peter, Cristina M; Hoffmann, Jéssica F; Picoli, Tony; Osório, Luiza da G; Chaves, Fábio; Zani, João L; de Faria, Renata O; de Mello, João R B; Meireles, Mário C A

    2017-04-01

    This study aimed to evaluate the chemical composition and cytotoxic activity of brown Brazilian propolis and its in vitro activity against itraconazole-resistant Sporothrix brasiliensis from animal sporotrichosis. Propolis was acquired commercially and prepared as a hydroalcoholic extract. Chemical analysis was evaluated by liquid chromatography coupled to mass spectrometry of ultra-efficiency. The cell viability was evaluated by MTT test in MDBK cells of 50 to 0.09 μg/mL. For antifungal tests, twenty isolates of Sporothrix brasiliensis from dogs (n = 11) and cats (n = 9) with sporotrichosis were tested to itraconazole (16-0.0313 μg/mL) and to propolis (3.125-0.09 mg/mL) by broth microdilution technique (CLSI M38-A2), adapted to natural products. The results were expressed in minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC). Itraconazole showed activity between MIC values of 0.25 to greater than 16 μg/mL, and 88.9% (08/09) and 72.7% (08/11) of S. brasiliensis from cats and dogs, respectively, were considered itraconazole-resistant. All Sporothrix brasiliensis were sensitive to brown propolis between MIC values of 0.19-1.56 mg/mL, including the itraconazole-resistant isolates, whereas the MFC values of propolis were from 0.78 to greater than 3.125 mg/mL. Propolis maintained a medium to high cell viability between concentration of 0.78 to 0.09 μg/mL, and p-coumaric acid was the major compound. Brown Brazilian propolis is a promising antifungal candidate against sporotrichosis and more studies need to be undertaken to evaluate its safe use to understand its efficacy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Influence of bath PH value on microstructure and corrosion resistance of phosphate chemical conversion coating on sintered Nd–Fe–B permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xia; Xue, Long-fei [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China); Wang, Xiu-chun [New Material Institute of Shandong Academy of Sciences, Jinan 250014 (China); Ding, Kai-hong; Cui, Sheng-li; Sun, Yong-cong [Yantai Shougang Magnetic Materials Inc., Yantai 265500 (China); Li, Mu-sen, E-mail: msli@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China)

    2016-10-15

    The effect of bath PH value on formation, microstructure and corrosion resistance of the phosphate chemical conversion (PCC) coatings as well as the effect on the magnetic property of the magnets is investigated in this paper. The results show that the coating mass and thickness increase with the decrease of the bath PH value. Scanning electron microscopy observation demonstrates that the PCC coatings are in a blocky structure with different grain size. Transmission electron microscope and X-ray diffractometer tests reveal the coatings are polycomponent and are mainly composed of neodymium phosphate hydrate and praseodymium phosphate hydrate. The electrochemical analysis and static immersion corrosion test show the corrosion resistance of the PCC coatings prepared at bath PH value of 0.52 is worst. Afterwards the corrosion resistance increases first and then decreases with the increasing of the bath PH values. The magnetic properties of all the samples with PCC treatment are decreased. The biggest loss is occurred when the bath PH value is 0.52. Taken together, the optimum PH range of 1.00–1.50 for the phosphate solution has been determined. - Highlights: • The coatings can be formed and present a blocky structure when the PH value is less than 2.00. • The coating mass and thickness increase with the decrease of the bath PH value. • The coatings are polycomponent and mainly composed of neodymium phosphate and praseodymium phosphate. • The optimum PH value range for formation of phosphate chemical conversion coatings is 1.00–1.50.

  10. Using biological and physico-chemical test methods to assess the role of concrete mixture design in resistance to microbially induced corrosion

    Science.gov (United States)

    House, Mitchell Wayne

    Concrete is the most widely used material for construction of wastewater collection, storage, and treatment infrastructure. The chemical and physical characteristics of hydrated portland cement make it susceptible to degradation under highly acidic conditions. As a result, some concrete wastewater infrastructure may be susceptible to a multi-stage degradation process known as microbially induced corrosion, or MIC. MIC begins with the production of aqueous hydrogen sulfide (H2S(aq)) by anaerobic sulfate reducing bacteria present below the waterline. H2S(aq) partitions to the gas phase where it is oxidized to sulfuric acid by the aerobic sulfur oxidizing bacteria Thiobacillus that resides on concrete surfaces above the waterline. Sulfuric acid then attacks the cement paste portion of the concrete matrix through decalcification of calcium hydroxide and calcium silica hydrate coupled with the formation of expansive corrosion products. The attack proceeds inward resulting in reduced service life and potential failure of the concrete structure. There are several challenges associated with assessing a concrete's susceptibility to MIC. First, no standard laboratory tests exist to assess concrete resistance to MIC. Straightforward reproduction of MIC in the laboratory is complicated by the use of microorganisms and hydrogen sulfide gas. Physico-chemical tests simulating MIC by immersing concrete specimens in sulfuric acid offer a convenient alternative, but do not accurately capture the damage mechanisms associated with biological corrosion. Comparison of results between research studies is difficult due to discrepancies that can arise in experimental methods even if current ASTM standards are followed. This thesis presents two experimental methods to evaluate concrete resistance to MIC: one biological and one physico-chemical. Efforts are made to address the critical aspects of each testing method currently absent in the literature. The first method presented is a new test

  11. Evaluation of Bacillus thuringiensis Pathogenicity for a Strain of the Tick, Rhipicephalus microplus, Resistant to Chemical Pesticides

    Science.gov (United States)

    Fernández-Ruvalcaba, Manuel; Peña-Chora, Guadalupe; Romo-Martínez, Armando; Hernández-Velázquez, Víctor; de Parra, Alejandra Bravo; De La Rosa, Diego Pérez

    2010-01-01

    The pathogenicity of four native strains of Bacillus thuringiensis against Rhipicephalus (Boophilus) microplus (Canestrine) (Acari: Ixodidae) was evaluated. A R. microplus strain that is resistant to organophosphates, pyrethroids, and amidines, was used in this study. Adult R. microplus females were bioassayed using the immersion test of Drummond against 60 B. thuringiensis strains. Four strains, GP123, GP138, GP130, and GP140, were found to be toxic. For the immersion test, the total protein concentration for each bacterial strain was 1.25 mg/ml. Mortality, oviposition, and egg hatch were recorded. All of the bacterial strains had significant effects compared to the controls, but no significant differences were seen between the 4 strains. It is evident that these B. thuringiensis strains have a considerable detrimental effect on the R. microplus strain that is resistant to pesticides. PMID:21062139

  12. Secondary and Primary Plant Metabolites as Chemical Markers for Resistance of Bitter Candytuft (Iberis amara) Plant against Insect Attack

    OpenAIRE

    Ayman Mohamed KAMEL; Soad Esawey EL-GENGAIHI

    2008-01-01

    A correlation between the levels of secondary and primary plant metabolites and food coefficient parameters with the population density of infested broccoli plants was studied. Cucurbitacins and glucosinolates compounds were good signs of resistance in bitter candytuft plants. On the other hand, lower values or the absence of these markers rendered broccoli susceptible to the pests under study, not during all stages of growth but whenever these values were much lower throughout growth stages....

  13. From micro-channels to nano-channels in a bilayer resist.

    Energy Technology Data Exchange (ETDEWEB)

    Ocola, L. E.; Stein, A.; Center for Nanoscale Materials; BNL

    2005-01-01

    This paper describes the use of a unique combination of an environmentally stable chemically amplified photoresist (UV113, Shipley) and a copolymer of methyl styrene and chloromethyl acrylate P(MS/CMA) resist (ZEP520, Zeon), without any additional intermediate layers, in the fabrication of micro- and nanochannels. The two resists used are innocuous to each other during the designed process flow, providing flexibility, high resolution, greater throughput and ease of use. We have also determined that the maximum channel length is limited by diffusion and mass transport effects, and that sub-100 nm nanochannels can be obtained with 30 micron lengths.

  14. BROADBAND TRAVELLING WAVE SEMICONDUCTOR OPTICAL AMPLIFIER

    DEFF Research Database (Denmark)

    2010-01-01

    Broadband travelling wave semiconductor optical amplifier (100, 200, 300, 400, 800) for amplification of light, wherein the amplifier (100, 200, 300, 400, 800) comprises a waveguide region (101, 201, 301, 401, 801) for providing confinement of the light in transverse directions and adapted...... for propagation of the light in at least a first mode along a longitudinal axis (102, 202, 302) of the amplifier (100, 200, 300, 400, 800) in a propagation direction (103, 203, 303), and wherein the waveguide region (101, 201, 301, 401, 801) comprises a gain region (104, 204, 304, 404, 804) for amplifying......, 301, 401, 801) increases along the longitudinal axis (102, 202, 302), and wherein the ratio between the width (106, 206, 306) of the waveguide region (101, 201, 301, 401, 801) and the width (107, 207, 307) of the gain region (104, 204, 304, 404, 804) increases along the longitudinal axis (102, 202...

  15. High Energy Single Frequency Resonant Amplifier Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a single frequency high energy resonant amplifier for remote sensing. Current state-of-art technologies can not provide all...

  16. Ku band low noise parametric amplifier

    Science.gov (United States)

    1976-01-01

    A low noise, K sub u-band, parametric amplifier (paramp) was developed. The unit is a spacecraft-qualifiable, prototype, parametric amplifier for eventual application in the shuttle orbiter. The amplifier was required to have a noise temperature of less than 150 K. A noise temperature of less than 120 K at a gain level of 17 db was achieved. A 3-db bandwidth in excess of 350 MHz was attained, while deviation from phase linearity of about + or - 1 degree over 50 MHz was achieved. The paramp operates within specification over an ambient temperature range of -5 C to +50 C. The performance requirements and the operation of the K sub u-band parametric amplifier system are described. The final test results are also given.

  17. EQUIPMENT WITH HYDROSTATIC AMPLIFIER MODELED 3D

    Directory of Open Access Journals (Sweden)

    EFTIMIE Dorin

    2013-11-01

    Full Text Available The equipment with hydrostatic amplifier is a new constructive solution modeled 3D using NX 7.5 software. Hydraulic equipment allows the amplification of a constant torque of a DC electric motor of low power at a variable speed. The hydrostatic speed amplifier of constant torque with electric control device is a hydraulic device which provides by design a bridge between the conventional hydraulic and the servo-hydraulic.

  18. Phase Noise in RF and Microwave Amplifiers

    OpenAIRE

    Boudot, Rodolphe; Rubiola, Enrico

    2010-01-01

    Understanding the amplifier phase noise is a critical issue in numerous fields of engineering and physics, like oscillators, frequency synthesis, telecommunications, radars, spectroscopy, in the emerging domain of microwave photonics, and in more exotic domains like radio astronomy, particle accelerators, etc. This article analyzes the two main types of phase noise in amplifiers, white and flicker. White phase noise results from adding white noise to the RF spectrum around the carrier. For a ...

  19. An audio FIR-DAC in a BCD process for high power Class-D amplifiers

    NARCIS (Netherlands)

    Doorn, T.S.; van Tuijl, Adrianus Johannes Maria; Schinkel, Daniel; Annema, Anne J.; Berkhout, M.; Berkhout, M.; Nauta, Bram

    A 322 coefficient semi-digital FIR-DAC using a 1-bit PWM input signal was designed and implemented in a high voltage, audio power bipolar CMOS DMOS (BCD) process. This facilitates digital input signals for an analog class-D amplifier in BCD. The FIR-DAC performance depends on the ISI-resistant

  20. Chemical Basis for Greenbug Resistance in Small Grains: II. Identification of the Major Neutral Metabolite of Benzyl Alcohol in Barley.

    Science.gov (United States)

    Juneja, P S; Pearcy, S C; Gholson, R K

    1975-09-01

    ((14)C)Benzyl alcohol was administered either by uptake through the roots or by injection directly into the stems of wheat (Triticum aestivum L. em Thell), sorghum (Sorghum bicolor. L Moench) and two strains of barley (Hordeum vulgare L.). One strain of barley was susceptible to the greenbug (Schizaphis granium Rondani), and the other was greenbug-resistant. In all four plants, several radioactive metabolites were formed. The major neutral metabolite has been identified as benzyl-beta-d-glucopyranoside. This glucoside was found to have no biological activity against the greenbug under conditions in which the parent compound, benzyl alcohol, inhibits the reproduction of this insect pest.

  1. Process Optimization for Monolithic Integration of Piezoresistive Pressure Sensor and MOSFET Amplifier with SOI Approach

    Science.gov (United States)

    Vinoth Kumar, V.; Dasgupta, A.; Bhat, K. N.; KNatarajan

    2006-04-01

    In this paper we present the design and process optimization for fabricating piezoresitive pressure sensor and MOSFET Differential Amplifier simultaneously on the same chip. Silicon On Insulator approach has been used for realizing the membrane as well as the electronics on the same chip. The amplifier circuit has been configured in the common source connection and it has been designed with PSPICE simulation to achieve a voltage gain of about 5. In the initial set of experiments the Pressure sensor and the amplifier were fabricated on separate chips to optimize the process steps and tested in the hybrid mode. In the next set of experiments, SOI wafer having the SOI layer thickness of about 11 microns was used for realizing the membrane by anisotropic etching from the backside. The piezo-resistive pressure sensor was realized on this membrane by connecting the polysilicon resistors in the form of a Wheatstone bridge. The MOSFET source follower amplifier was also fabricated on the same SOI wafer by tailoring the process steps to suit the requirement of simultaneous fabrication of piezoresistors and the amplifier for achieving MOSFET Integrated Pressure Sensor. Reproducible results have been achieved on the SOI wafers, with the process steps developed in the laboratory. Sensitivity of 270 mV /Bar/10V, with the on chip amplifier gain of 4.5, has been achieved with this process.

  2. Ultra-low noise miniaturized neural amplifier with hardware averaging.

    Science.gov (United States)

    Dweiri, Yazan M; Eggers, Thomas; McCallum, Grant; Durand, Dominique M

    2015-08-01

    Peripheral nerves carry neural signals that could be used to control hybrid bionic systems. Cuff electrodes provide a robust and stable interface but the recorded signal amplitude is small (noise of less than 1 μVrms for a useful signal-to-noise ratio (SNR). Flat interface nerve electrode (FINE) contacts alone generate thermal noise of at least 0.5 μVrms therefore the amplifier should add as little noise as possible. Since mainstream neural amplifiers have a baseline noise of 2 μVrms or higher, novel designs are required. Here we apply the concept of hardware averaging to nerve recordings obtained with cuff electrodes. An optimization procedure is developed to minimize noise and power simultaneously. The novel design was based on existing neural amplifiers (Intan Technologies, LLC) and is validated with signals obtained from the FINE in chronic dog experiments. We showed that hardware averaging leads to a reduction in the total recording noise by a factor of 1/√N or less depending on the source resistance. Chronic recording of physiological activity with FINE using the presented design showed significant improvement on the recorded baseline noise with at least two parallel operation transconductance amplifiers leading to a 46.1% reduction at N = 8. The functionality of these recordings was quantified by the SNR improvement and shown to be significant for N = 3 or more. The present design was shown to be capable of generating noise when connected to a FINE placed on the sciatic nerve of an awake animal. An algorithm was introduced to find the value of N that can minimize both the power consumption and the noise in order to design a miniaturized ultralow-noise neural amplifier. These results demonstrate the efficacy of hardware averaging on noise improvement for neural recording with cuff electrodes, and can accommodate the presence of high source impedances that are associated with the miniaturized contacts and the high channel count in electrode arrays. This

  3. Ultra-low noise miniaturized neural amplifier with hardware averaging

    Science.gov (United States)

    Dweiri, Yazan M.; Eggers, Thomas; McCallum, Grant; Durand, Dominique M.

    2015-08-01

    Objective. Peripheral nerves carry neural signals that could be used to control hybrid bionic systems. Cuff electrodes provide a robust and stable interface but the recorded signal amplitude is small (noise of less than 1 μVrms for a useful signal-to-noise ratio (SNR). Flat interface nerve electrode (FINE) contacts alone generate thermal noise of at least 0.5 μVrms therefore the amplifier should add as little noise as possible. Since mainstream neural amplifiers have a baseline noise of 2 μVrms or higher, novel designs are required. Approach. Here we apply the concept of hardware averaging to nerve recordings obtained with cuff electrodes. An optimization procedure is developed to minimize noise and power simultaneously. The novel design was based on existing neural amplifiers (Intan Technologies, LLC) and is validated with signals obtained from the FINE in chronic dog experiments. Main results. We showed that hardware averaging leads to a reduction in the total recording noise by a factor of 1/√N or less depending on the source resistance. Chronic recording of physiological activity with FINE using the presented design showed significant improvement on the recorded baseline noise with at least two parallel operation transconductance amplifiers leading to a 46.1% reduction at N = 8. The functionality of these recordings was quantified by the SNR improvement and shown to be significant for N = 3 or more. The present design was shown to be capable of generating noise when connected to a FINE placed on the sciatic nerve of an awake animal. An algorithm was introduced to find the value of N that can minimize both the power consumption and the noise in order to design a miniaturized ultralow-noise neural amplifier. Significance. These results demonstrate the efficacy of hardware averaging on noise improvement for neural recording with cuff electrodes, and can accommodate the presence of high source impedances that are associated with the miniaturized contacts and

  4. Chemical Composition, Modulatory Bacterial Resistance and Antimicrobial Activity of Essential Oil the Hyptis martiusii Benth by Direct and Gaseous Contact.

    Science.gov (United States)

    de Oliveira, Allan Demetrius Leite; Galvao Rodrigue, Fabiola Fernandes; Douglas Melo Coutinho, Henrique; da Costa, Jose Galberto Martins; de Menezes, Irwin Rose Alencar

    2014-08-01

    Several studies have shown that species of the genus Hyptis, have promising antimicrobial and antifungal effects. Identify of chemical constituents of essential oil from leaves of Hyptis martiusii and evaluate its effect against bacterial strains by direct and gaseous contact. Essential oil was extracted from leaves of Hyptis martiusii Benth using hydro-distillation, and its composition was determined using gas chromatography-mass spectrometry (GC-MS). Chemical analysis showed that there was a predominance of sesquiterpenes. The leaf essential oil was screened for its minimal inhibitory concentration and modulatory effect of aminoglycoside by the direct (MIC) and gaseous (MID) micro-dilution assays for various pathogenic microorganisms. The essential oil remarkably inhibited the growth of all of the tested bacteria (MIC essential oil of leaves were characterized; δ -3-carene (6.88%), 1, 8-cineole (7.01%), trans-caryophyllene (9.21%), Cariophyllene oxide (7.47%) and bicyclogermacrene (10.61%) were found as the major components. Modulatory aminoglycoside effect, by direct contact, was showed antagonistic relationship with antimicrobial activity. The gaseous component of the oil inhibited the bacterial growth of all of the tested bacteria in 50% and 25% of oil concentration and demonstrated synergistic interactions can be attributed to the constituting the oil compounds. These results show that this oil influences the activity of the antibiotic and may be used as an adjuvant in the antibiotic therapy of respiratory tract bacterial pathogens.

  5. Plasma-chemical synthesis of carbon nanotubes and fullerenes to create frost-resistant composite building materials

    Science.gov (United States)

    Semenov, A. P.; Smirnyagina, N. N.; Tsyrenov, B. O.; Dasheev, D. E.; Khaltarov, Z. M.

    2017-05-01

    This paper considers a method of synthesis fullerenes and carbon nanotubes at atmospheric pressure. Carbon evaporates into the plasma arc. The paper discusses the method of synthesis of helium at a pressure of 105 Pa. We show the dependence yield of fullerenes and carbon nanotubes from the buffer gas pressure. It has been found that the fullerene yield increased with increasing pressure. The obtained fullerenes and nanotubes find their application in the modification of construction materials. The use of carbon nanomodifiers in the modification of the construction is promising since their introduction significantly improves the physico-mechanical properties using a small quantity of additives. With the introduction of the carbon nanomodifier decrease the porosity of cement stone, which leads to high strength and frost-resistant indicators of the modified cement.

  6. Development of a Low-Noise High Common-Mode-Rejection Instrumentation Amplifier. M.S. Thesis

    Science.gov (United States)

    Rush, Kenneth; Blalock, T. V.; Kennedy, E. J.

    1975-01-01

    Several previously used instrumentation amplifier circuits were examined to find limitations and possibilities for improvement. One general configuration is analyzed in detail, and methods for improvement are enumerated. An improved amplifier circuit is described and analyzed with respect to common mode rejection and noise. Experimental data are presented showing good agreement between calculated and measured common mode rejection ratio and equivalent noise resistance. The amplifier is shown to be capable of common mode rejection in excess of 140 db for a trimmed circuit at frequencies below 100 Hz and equivalent white noise below 3.0 nv/square root of Hz above 1000 Hz.

  7. Resist requirements and limitations for nanoscale electron-beam patterning.

    Energy Technology Data Exchange (ETDEWEB)

    Liddle, J. A.; Gallatin, G. M.; Ocola, L. E.; Experimental Facilities Division (APS); LBNL; IBM T.J. Watson Research Center

    2003-01-01

    Electron beam lithography still represents the most effective way to pattern materials at the nanoscale, especially in the case of structures, which are not indefinitely repeating a simple motif. The success of e-beam lithography depends on the availability of suitable resists. There is a substantial variety of resist materials, from PMMA to calixarenes, to choose from to achieve high resolution in electron-beam lithography. However, these materials suffer from the limitation of poor sensitivity and poor contrast. In both direct-write and projection e-beam systems the maximum beam current for a given resolution is limited by space-charge effects. In order to make the most efficient use of the available current, the resist must be as sensitive as possible. This leads, naturally, to the use of chemically amplified (CA) systems. Unfortunately, in the quest for ever smaller feature sizes and higher throughputs, even chemically amplified materials are limited: ultimately, sensitivity and resolution are not independent. Current resists already operate in the regime of < 1 electron/nm2. In this situation detailed models are the only way to understand material performance and limits. Resist requirements, including sensitivity, etch selectivity, environmental stability, outgassing, and line-edge roughness as they pertain to, high-voltage (100 kV) direct write and projection electron-beam exposure systems are described. Experimental results obtained on CA resists in the SCALPEL exposure system are presented and the fundamental sensitivity limits of CA and conventional materials in terms of shot-noise and resolution limits in terms of electron-beam solid interactions are discussed.

  8. New laser amplifier improves laser Doppler interferometry

    Science.gov (United States)

    1986-02-01

    The design of a laser light amplifier developed to improve the ability of a laser Doppler interferometry system to measure the high velocities of explosion-driven objects or targets is described. The amplifier increases the laser light intensity and S/N ratio. A green coumarin dye is utilized as if the lasing medium for an argon-ion laser and a blue dye as the frequency shifter to improve coupling between the light-pump power source and lasing medium. The arrangement of amplifier components and the frequency characteristics of the flash lamps and dyes are examined. The design requirements for eliminating chirping and achieving acoustic isolation are discussed. The control of the thermal gradients which produce lens effect is analyzed. The selection of a proper dye concentration for uniform excitation across the active volume of the amplifier is studied; an excitation absorption length of three diameters of active cross section is utilized. In order to increase the amount of pumping light reaching the laser dye and to reduce the number of unwanted wavelengths a optical frequency shifter is employed. The amplifier produces enough light to observe two or more spots on the target, record data for up to 12 microsec, and have an accuracy of 0.5 pct.

  9. Transpermeance Amplifier Applied to Magnetic Bearings

    Directory of Open Access Journals (Sweden)

    Jossana Ferreira

    2017-02-01

    Full Text Available The most conventional approach of controlling magnetic forces in active magnetic bearings (AMBs is through current feedback amplifiers: transconductance. This enables the operation of the AMB to be understood in terms of a relatively simple current-based model as has been widely reported on in the literature. The alternative notion of using transpermeance amplifiers, which approximate the feedback of gap flux rather than current, has been in commercial use in some form for at least thirty years, however is only recently seeing more widespread acceptance as a commercial standard. This study explores how such alternative amplifiers should be modeled and then examines the differences in behavior between AMBs equipped with transconductance and transpermeance amplifiers. The focus of this study is on two aspects. The first is the influence of rotor displacement on AMB force, commonly modeled as a constant negative equivalent mechanical stiffness, and it is shown that either scheme actually leads to a finite bandwidth effect, but that this bandwidth is much lower when transpermeance is employed. The second aspect is the influence of eddy currents. Using a very simple model of eddy currents (a secondary short-circuited coil, it is demonstrated that transpermeance amplifiers can recover significant actuator bandwidth compared with transconductance, but at the cost of needing increased peak current headroom.

  10. The OPTHER Project: Progress toward the THz Amplifier

    DEFF Research Database (Denmark)

    Paoloni, C; Brunetti, F; Di Carlo, A

    2011-01-01

    This paper describes the status of the OPTHER (OPtically driven TeraHertz AmplifiERs) project and progress toward the THz amplifier realization. This project represents a considerable advancement in the field of high frequency amplification. The design and realization of a THz amplifier within th...

  11. Wideband Low Noise Amplifiers Exploiting Thermal Noise Cancellation

    NARCIS (Netherlands)

    Bruccoleri, F.; Klumperink, Eric A.M.; Nauta, Bram

    2005-01-01

    Low Noise Amplifiers (LNAs) are commonly used to amplify signals that are too weak for direct processing for example in radio or cable receivers. Traditionally, low noise amplifiers are implemented via tuned amplifiers, exploiting inductors and capacitors in resonating LC-circuits. This can render

  12. ZigBee Radio with External Power Amplifier and Low-Noise Amplifier

    Directory of Open Access Journals (Sweden)

    Allan HUYNH

    2010-07-01

    Full Text Available This paper presents the performance study of a ZigBee module with both an external power amplifier and a low-noise amplifier, measured in outdoor and indoor environments, respectively. Our previous study has already shown that the indoor campus environment such as walls and floors would reduce the radio link range drastically and the packet error rate increased. In this study, both an external power amplifier and a low-noise amplifier have been added to a ZigBee module to increase both the transmitter power and receiver sensitivity. It is shown that with an external power amplifier and a low-noise amplifier the outdoor radio range can reach up to 1600 m with a negligible packet error rate compared to 144 m without any external amplifier for point-to-point radio connection. Thus, by increasing both the transmitter power and receiver sensitivity the radio range can be increased significantly. The power consumption issue with the added amplifiers is studied as well, indicating that the module can still be battery driven with a battery lifetime of about 9 years at a normal sampling rate to the sensor.

  13. Arbuscular mycorrhizal colonization alters subcellular distribution and chemical forms of cadmium in Medicago sativa L. and resists cadmium toxicity.

    Science.gov (United States)

    Wang, Yuanpeng; Huang, Jing; Gao, Yanzheng

    2012-01-01

    Some plants can tolerate and even detoxify soils contaminated with heavy metals. This detoxification ability may depend on what chemical forms of metals are taken up by plants and how the plants distribute the toxins in their tissues. This, in turn, may have an important impact on phytoremediation. We investigated the impact of arbuscular mycorrhizal (AM) fungus, Glomus intraradices, on the subcellular distribution and chemical forms of cadmium (Cd) in alfalfa (Medicago sativa L.) that were grown in Cd-added soils. The fungus significantly colonized alfalfa roots by day 25 after planting. Colonization of alfalfa by G. intraradices in soils contaminated with Cd ranged from 17% to 69% after 25-60 days and then decreased to 43%. The biomass of plant shoots with AM fungi showed significant 1.7-fold increases compared to no AM fungi addition under the treatment of 20 mg kg(-1) Cd. Concentrations of Cd in the shoots of alfalfa under 0.5, 5, and 20 mgkg(-1) Cd without AM fungal inoculation are 1.87, 2.92, and 2.38 times higher, respectively, than those of fungi-inoculated plants. Fungal inoculation increased Cd (37.2-80.5%) in the cell walls of roots and shoots and decreased in membranes after 80 days of incubation compared to untreated plants. The proportion of the inactive forms of Cd in roots was higher in fungi-treated plants than in controls. Furthermore, although fungi-treated plants had less overall Cd in subcellular fragments in shoots, they had more inactive Cd in shoots than did control plants. These results provide a basis for further research on plant-microbe symbioses in soils contaminated with heavy metals, which may potentially help us develop management regimes for phytoremediation.

  14. Design Of A Doherty Power Amplifier For GSM Systems

    Directory of Open Access Journals (Sweden)

    Saad Wasmi Osman

    2013-04-01

    Full Text Available This paper presents the design and analysis of Doherty power amplifier. The Doherty amplifier is used in  a base station for mobile system because of its high efficiency. The class AB power amplifier used in the configuration of the main and auxiliary amplifier. The result obtained shows that the Doherty power amplifier can be used on a wide band spectrum, the amplifier works at 900MHz and has very good power added efficiency (PAE and gain. The amplifier can also work at 1800MHz at input power greater than 20dBm. 

  15. Efficiency Investigation of Switch Mode Power Amplifier Drving Low Impedance Transducers

    DEFF Research Database (Denmark)

    Iversen, Niels Elkjær; Schneider, Henrik; Knott, Arnold

    2015-01-01

    The typical nominal resistance span of an electro dynamic transducer is 4 Ω to 8 Ω. This work examines the possibility of driving a transducer with a much lower impedance to enable the amplifier and loudspeaker to be directly driven by a low voltage source such as a battery. A method for estimati...... performance leap in terms of efficiency compared to a conventional battery driven sound system. Future optimization of low voltage, high current amplifiers for low impedance loudspeaker drivers are discussed.......The typical nominal resistance span of an electro dynamic transducer is 4 Ω to 8 Ω. This work examines the possibility of driving a transducer with a much lower impedance to enable the amplifier and loudspeaker to be directly driven by a low voltage source such as a battery. A method for estimating...... the amplifier rail voltage requirement as a function of the voice coil nominal resistance is presented. The method is based on a crest factor analysis of music signals and estimation of the electrical power requirement from a specific target of the sound pressure level. Experimental measurements confirms a huge...

  16. Distributed feedback laser amplifiers combining the functions of amplifiers and channel filters

    DEFF Research Database (Denmark)

    Wang, Z.; Durhuus, T.; Mikkelsen, Benny

    1994-01-01

    A dynamic model for distributed feedback amplifiers, including the mode coupled equations and the carrier rate equation, is established. The presented mode coupled equations have taken into account the interaction between fast changing optical signal and the waveguide with corrugations. By showin...... the possibility of amplifying 100 ps pulses without pulse broadening, we anticipate that a distributed feedback amplifier can be used as a combined amplifier and channel filter in high bit rate transmission systems.......A dynamic model for distributed feedback amplifiers, including the mode coupled equations and the carrier rate equation, is established. The presented mode coupled equations have taken into account the interaction between fast changing optical signal and the waveguide with corrugations. By showing...

  17. The effect of astaxanthin on resistance of juvenile prawns Macrobrachium nipponense (Decapoda: Palaemonidae to physical and chemical stress

    Directory of Open Access Journals (Sweden)

    Babak Tizkar

    2014-12-01

    Full Text Available In recent years, the use of new scientific techniques has effectively improved aquaculture production processes. Astaxanthin has various properties in aquacultureand its antioxidant benefits have been closely related to stress resistance; besides, it is an essential factor for growth in many crustaceans and fish. The objective of this study was to evaluate the resistance of prawn (Macrobrachium nipponense fed diets containing different amounts of astaxanthin (AX to the shock and stress of differentphysicochemical environments. A 70-day trial was conducted to evaluate the effect of supplementation of a source of astaxanthin (Carophyll Pink, 10% astaxanthin, w/w, Hoffman-La Roche, Switzerland at various levels in the diet of M. nipponense juveniles. Four dry diets were prepared: AX0 without astaxanthin, AX50 with 50mg/kg, AX100 with 100mg/kg, and AX150 with 150mg/kg astaxanthin. The feeding trial was conducted in a recirculation water system consisting of 12 fiberglass tanks (1 000L used for holding prawns. Three replicate aquaria were initially stocked with 36org/m² per tank. During the trial, prawns were maintained on a 12:12-h light:dark photoperiod with an ordinary incandescent lamp, and the water quality parameters were maintained as follows: water temperature, 25-26°C; salinity, 1g/L; pH, 8.5-8.8; dissolved oxygen, 6.0-6.5mg/L; and ammonia-nitrogen, 0.05mg/L. Incorporation of AX, production output, and physiological condition were recorded after 10 weeks of feeding. At the end of the growing period, the prawns were exposed to thermal shock (0°C, ammonia (0.75mg/L, and reduced oxygen (0.5mg/L. The time to lethargyand the time to complete death of the prawns were recorded. The results showed that control prawns had the shortest time to lethargy and death compared with prawns subjected to the other treatments. The results of this study have shown that the amount of muscle tissue and gill carotenoids in prawn fed with an AX150 diet showed

  18. The effect of astaxanthin on resistance of juvenile prawns Macrobrachium nipponense (Decapoda: Palaemonidae) to physical and chemical stress.

    Science.gov (United States)

    Tizkar, Babak; Seidavi, Alireza; Ponce-Palafox, Jesús Trinidad; Pourashoori, Parastoo

    2014-12-01

    In recent years, the use of new scientific techniques has effectively improved aquaculture production processes. Astaxanthin has various properties in aquaculture and its antioxidant benefits have been closely related to stress resistance; besides, it is an essential factor for growth in many crustaceans and fish. The objective of this study was to evaluate the resistance of prawn (Macrobrachium nipponense) fed diets containing different amounts of astaxanthin (AX) to the shock and stress of different physicochemical environments. A 70-day trial was conducted to evaluate the effect of supplementation of a source of astaxanthin (Carophyll Pink, 10% astaxanthin, w/w, Hoffman-La Roche, Switzerland) at various levels in the diet of M. nipponense juveniles. Four dry diets were prepared: AX0 without astaxanthin, AX50 with 50 mg/kg, AX100 with 100 mg/kg, and AX150 with 150 mg/kg astaxanthin. The feeding trial was conducted in a recirculation water system consisting of 12 fiberglass tanks (1000L) used for holding prawns. Three replicate aquaria were initially stocked with 36 org/m2 per tank. During the trial, prawns were maintained on a 12:12-h light:dark photoperiod with an ordinary incandescent lamp, and the water quality parameters were maintained as follows: water temperature, 25-26°C; salinity, 1 g/L; pH, 8.5-8.8; dissolved oxygen, 6.0-6.5 mg/L; and ammonia-nitrogen, 0.05 mg/L. Incorporation of AX, production output, and physiological condition were recorded after 10 weeks of feeding. At the end of the growing period, the prawns were exposed to thermal shock (0°C), ammonia (0.75 mg/L), and reduced oxygen (0.5 mg/L). The time to lethargy and the time to complete death of the prawns were recorded. The results showed that control prawns had the shortest time to lethargy and death compared with prawns subjected to the other treatments. The results of this study have shown that the amount of muscle tissue and gill carotenoids in prawn fed with an AX150 diet showed

  19. Wideband pulse amplifiers for the NECTAr chip

    Energy Technology Data Exchange (ETDEWEB)

    Sanuy, A., E-mail: asanuy@ecm.ub.es [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Delagnes, E. [IRFU/DSM/CEA, CE-Saclay, Bat. 141 SEN Saclay, F-91191, Gif-sur-Yvette (France); Gascon, D. [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Sieiro, X. [Departament d' Electronica, Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Bolmont, J.; Corona, P. [LPNHE, Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Barre 12-22, 1er etage, 4 place Jussieu, 75252 Paris (France); Feinstein, F. [LUPM, Universite Montpellier II and IN2P3/CNRS, CC072, bat. 13, place Eugene Bataillon, 34095 Montpellier (France); Glicenstein, J-F. [IRFU/DSM/CEA, CE-Saclay, Bat. 141 SEN Saclay, F-91191, Gif-sur-Yvette (France); Naumann, C.L.; Nayman, P. [LPNHE, Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Barre 12-22, 1er etage, 4 place Jussieu, 75252 Paris (France); Ribo, M. [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); and others

    2012-12-11

    The NECTAr collaboration's FE option for the camera of the CTA is a 16 bits and 1-3 GS/s sampling chip based on analog memories including most of the readout functions. This works describes the input amplifiers of the NECTAr ASIC. A fully differential wideband amplifier, with voltage gain up to 20 V/V and a BW of 400 MHz. As it is impossible to design a fully differential OpAmp with an 8 GHz GBW product in a 0.35 CMOS technology, an alternative implementation based on HF linearized transconductors is explored. The output buffer is a class AB miller operational amplifier, with special non-linear current boost.

  20. Optimal reduction of chemical oxygen demand and NH3-N from landfill leachate using a strongly resistant novel Bacillus salmalaya strain.

    Science.gov (United States)

    Dadrasnia, Arezoo; Azirun, Mohd Sofian; Ismail, Salmah Binti

    2017-11-28

    When the unavoidable waste generation is considered as damaging to our environment, it becomes crucial to develop a sustainable technology to remediate the pollutant source towards an environmental protection and safety. The development of a bioengineering technology for highly efficient pollutant removal is this regard. Given the high ammonia nitrogen content and chemical oxygen demand of landfill leachate, Bacillus salmalaya strain 139SI, a novel resident strain microbe that can survive in high ammonia nitrogen concentrations, was investigated for the bioremoval of ammonia nitrogen from landfill leachate. The treatability of landfill leachate was evaluated under different treatment parameters, such as temperature, inoculum dosage, and pH. Results demonstrated that bioaugmentation with the novel strain can potentially improve the biodegradability of landfill leachate. B. salmalaya strain 139SI showed high potential to enhance biological treatment given its maximum NH3-N and COD removal efficiencies. The response surface plot pattern indicated that within 11 days and under optimum conditions (10% v/v inoculant, pH 6, and 35 °C), B. salmalaya strain139SI removed 78% of ammonia nitrogen. At the end of the study, biological and chemical oxygen demands remarkably decreased by 88% and 91.4%, respectively. Scanning electron microscopy images revealed that ammonia ions covered the cell surface of B. salmalaya strain139SI. Therefore, novel resistant Bacillus salmalaya strain139SI significantly reduces the chemical oxygen demand and NH3-N content of landfill leachate. Leachate treatment by B. salmalaya strain 139SI within 11 days.

  1. Insight into the mechanism of chemical modification of antibacterial agents by antibiotic resistance enzyme O-phosphotransferase-IIIA.

    Science.gov (United States)

    Power, Blake Hollett; Smith, Nathan; Downer, Brandon; Alisaraie, Laleh

    2017-01-01

    In the present work, the mechanism of resistance to aminoglycoside antibiotics was investigated. We examined the conformational changes of the O-phosphotransferase-IIIa enzyme, complexed with the antibiotics using MD simulations. The inhibitory effects of a group of antibacterial peptides against the enzyme were also examined, among which CP10A showed the highest affinity and the results correlated with the measured IC50 values. The regioselectivity of the phosphorylation reaction was shown to be in favor of the OH at the 5″ position versus the 3' of the antibiotic. The binding mode of CP10A was evaluated by means of MD simulation that resulted in recognizing its Trp8 and Arg13 residues binding near to where residues at the 3' and 5″ positions of the antibiotic would bind; thus, they are essential for the peptide inhibitory effect. The major open, semi-open, and closed conformations of the binding sites were identified throughout the MD trajectory, which enable the enzyme to regulate the influx of molecules into these sites. Based on the enzyme crystal structure, it was assumed that the 'antibiotic loop' of the enzyme is stable in its liganded mode; however, MD results revealed that the loop is highly flexible in both liganded and ligand-free modes. © 2016 John Wiley & Sons A/S.

  2. Chemical control of California arrowhead (Sagittaria montevidensis resistant to acetolactate synthase and photosystem II inhibiting herbicides in irrigated rice

    Directory of Open Access Journals (Sweden)

    Diogo da Silva Moura

    Full Text Available ABSTRACT: California arrowhead is one of the primary weeds infesting paddy rice fields in the Brazilian states of Santa Catarina and Rio Grande do Sul, where the system of pre-germinated seeding is used. The objective of this study was to evaluate the selectivity and effectiveness of saflufenacil application in irrigated rice, either singly or in combination with other herbicides in the same application or sequentially, for the control of Sagittaria montevidensis biotype that is resistant to ALSand PSII-inhibiting herbicides. In the first experiment carried out in a greenhouse, saflufenacil was applied, either singly or in combination with penoxsulam, bispyribac-sodium, pyrazosulfuron-ethyl, bentazon, or propanil to the S. montevidensis (SAGMO 32 biotype and the irrigated rice variety Epagri 108. In the second experiment, single or combined (including sequential applications of saflufenacil, bentazon, and cyhalofop-butyl were applied to Epagri 108 in open field conditions. Saflufenacil combined with propanil showed a high degree of phytotoxicity and a reduction in the accumulation of dry mass in Epagri 108. Application of saflufenacil, bentazon, and cyhalofop-butyl in combination or sequentially resulted in an increase in phytotoxicity in Epagri 108 compared to when applied singly. A pplication of saflufenacil singly or in combination with penoxsulam, bispyribac-sodium, bentazon, or pyrazosulfuron-ethyl did not adequately control SAGMO 32.

  3. The role of the local chemical environment of Ag on the resistive switching mechanism of conductive bridging random access memories.

    Science.gov (United States)

    Souchier, E; D'Acapito, F; Noé, P; Blaise, P; Bernard, M; Jousseaume, V

    2015-10-07

    Conductive bridging random access memories (CBRAMs) are one of the most promising emerging technologies for the next generation of non-volatile memory. However, the lack of understanding of the switching mechanism at the nanoscale level prevents successful transfer to industry. In this paper, Ag/GeSx/W CBRAM devices are analyzed using depth selective X-ray Absorption Spectroscopy before and after switching. The study of the local environment around Ag atoms in such devices reveals that Ag is in two very distinct environments with short Ag-S bonds due to Ag dissolved in the GeSx matrix, and longer Ag-Ag bonds related to an Ag metallic phase. These experiments allow the conclusion that the switching process involves the formation of metallic Ag nano-filaments initiated at the Ag electrode. All these experimental features are well supported by ab initio molecular dynamics simulations showing that Ag favorably bonds to S atoms, and permit the proposal of a model at the microscopic level that can explain the instability of the conductive state in these Ag-GeSx CBRAM devices. Finally, the principle of the nondestructive method described here can be extended to other types of resistive memory concepts.

  4. Operational amplifier circuits analysis and design

    CERN Document Server

    Nelson, J C C

    1995-01-01

    This book, a revised and updated version of the author's Basic Operational Amplifiers (Butterworths 1986), enables the non-specialist to make effective use of readily available integrated circuit operational amplifiers for a range of applications, including instrumentation, signal generation and processing.It is assumed the reader has a background in the basic techniques of circuit analysis, particularly the use of j notation for reactive circuits, with a corresponding level of mathematical ability. The underlying theory is explained with sufficient but not excessive, detail. A range of compu

  5. Plasma Wave Seed for Raman Amplifiers

    Science.gov (United States)

    Qu, Kenan; Barth, Ido; Fisch, Nathaniel

    2016-10-01

    It is proposed to replace traditionally used laser seed in backward Raman amplifiers with initial plasma wave seed. We show, analytically and numerically, that similarly to laser seeds plasma seeds result in Raman amplified pulse in both the linear and nonlinear regimes. The plasma seed is prepared in advance with a certain wavevector and envelope at one edge of the plasma. This methodology is attractive because it avoids issues in preparing and synchronizing frequency shifted laser seed. This work was supported by NNSA Grant No. DE-NA0002948, AFOSR Grant No. FA9550-15-1-0391.

  6. Predistortion of a Bidirectional Cuk Audio Amplifier

    DEFF Research Database (Denmark)

    Birch, Thomas Hagen; Nielsen, Dennis; Knott, Arnold

    2014-01-01

    using predistortion. This paper suggests linearizing a nonlinear bidirectional Cuk audio amplifier using an analog predistortion approach. A prototype power stage was built and results show that a voltage gain of up to 9 dB and reduction in THD from 6% down to 3% was obtainable using this approach.......Some non-linear amplifier topologies are capable of providing a larger voltage gain than one from a DC source, which could make them suitable for various applications. However, the non-linearities introduce a significant amount of harmonic distortion (THD). Some of this distortion could be reduced...

  7. A novel amino acid substitution Trp574Arg in acetolactate synthase (ALS) confers broad resistance to ALS-inhibiting herbicides in crabgrass (Digitaria sanguinalis).

    Science.gov (United States)

    Li, Jian; Li, Mei; Gao, Xingxiang; Fang, Feng

    2017-06-23

    Crabgrass (Digitaria sanguinalis) is an annual monocotyledonous weed. In recent years, field applications of nicosulfuron have been ineffective in controlling crabgrass populations in Shandong Province, China. To investigate the mechanisms of resistance to nicosulfuron in crabgrass populations, the acetolactate synthase (ALS) gene fragment covering known resistance-confering mutation sites was amplified and sequenced. Dose-response experiments suggested that the resistant population SD13 (R) was highly resistant to nicosulfuron (resistance index R/S = 43.7) compared with the sensitive population SD22 (S). ALS gene sequencing revealed a Trp574Arg substitution in the SD13 population, and no other known resistance-conferring mutations were found. In vitro ALS enzyme assays further confirmed that the SD13 population was resistant to all tested ALS-inhibiting herbicides. The resistance pattern experiments revealed that, compared with SD22, the SD13 population exhibited broad-spectrum resistance to nicosulfuron (43.7-fold), imazethapyr (11.4-fold) and flumetsulam (16.1-fold); however, it did not develop resistance to atrazine, mesotrione and topramezone. This study demonstrated that Trp574Arg substitution was the main reason for crabgrass resistance to ALS-inhibiting herbicides. To our knowledge, this is the first report of Trp574Arg substitution in a weed species, and is the first report of target-site mechanisms of herbicide resistance for crabgrass. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  8. High‐Efficiency CMOS Power Amplifier Using Uneven Bias for Wireless LAN Application

    National Research Council Canada - National Science Library

    Ryu, Namsik; Jung, Jae‐Ho; Jeong, Yongchae

    2012-01-01

    This paper proposes a high‐efficiency power amplifier (PA) with uneven bias. The proposed amplifier consists of a driver amplifier, power stages of the main amplifier with class AB bias, and an auxiliary amplifier with class C bias...

  9. Frequency Compensation of an Audio Power Amplifier

    NARCIS (Netherlands)

    van der Zee, Ronan A.R.; van Heeswijk, R.

    2006-01-01

    A car audio power amplifier is presented that uses a frequency compensation scheme which avoids large compensation capacitors around the MOS power transistors, while retaining the bandwidth and stable load range of nested miller compensation. THD is 0.005%@(1kHz, 10W), SNR is 108dB, and the

  10. Molecular markers. Amplified fragment length polymorphism

    Directory of Open Access Journals (Sweden)

    Pržulj Novo

    2005-01-01

    Full Text Available Amplified Fragment Length Polymorphism molecular markers (AFLPs has been developed combining procedures of RFLPs and RAPDs molekular markers, i.e. the first step is restriction digestion of the genomic DNA that is followed by selective amplification of the restricted fragments. The advantage of the AFLP technique is that it allows rapid generation of a large number of reproducible markers. The reproducibility of AFLPs markers is assured by the use of restriction site-specific adapters and adapter-specific primers for PCR reaction. Only fragments containing the restriction site sequence plus the additional nucleotides will be amplified and the more selected nucleotides added on the primer sequence the fewer the number of fragments amplified by PCR. The amplified products are normally separated on a sequencing gel and visualized after exposure to X-ray film or by using fluorescent labeled primers. AFLP shave proven to be extremely proficient in revealing diversity at below the species level. A disadvantage of AFLP technique is that AFLPs are essentially a dominant marker system and not able to identify heterozygotes.

  11. Using optimized random amplified polymorphic DNA (RAPD ...

    African Journals Online (AJOL)

    Citrus nobilis Lour. Gonggan is an excellent fruit variety which is widely planted in South China. The origin of Gonggan is not clear. It is conjectured that its origin is from a cross between tangerine and orange; however, there is no direct evidence to confirm this. Here, we applied the optimized random amplified polymorphic ...

  12. Stereoscopy Amplifies Emotions Elicited by Facial Expressions

    Directory of Open Access Journals (Sweden)

    Jussi Hakala

    2015-11-01

    Full Text Available Mediated facial expressions do not elicit emotions as strongly as real-life facial expressions, possibly due to the low fidelity of pictorial presentations in typical mediation technologies. In the present study, we investigated the extent to which stereoscopy amplifies emotions elicited by images of neutral, angry, and happy facial expressions. The emotional self-reports of positive and negative valence (which were evaluated separately and arousal of 40 participants were recorded. The magnitude of perceived depth in the stereoscopic images was manipulated by varying the camera base at 15, 40, 65, 90, and 115 mm. The analyses controlled for participants’ gender, gender match, emotional empathy, and trait alexithymia. The results indicated that stereoscopy significantly amplified the negative valence and arousal elicited by angry expressions at the most natural (65 mm camera base, whereas stereoscopy amplified the positive valence elicited by happy expressions in both the narrowed and most natural (15–65 mm base conditions. Overall, the results indicate that stereoscopy amplifies the emotions elicited by mediated emotional facial expressions when the depth geometry is close to natural. The findings highlight the sensitivity of the visual system to depth and its effect on emotions.

  13. Modeling Power Amplifiers using Memory Polynomials

    NARCIS (Netherlands)

    Kokkeler, Andre B.J.

    2005-01-01

    In this paper we present measured in- and output data of a power amplifier (PA). We compare this data with an AM-AM and AM-PM model. We conclude that a more sophisticated PA model is needed to cope with severe memory effects. We suggest to use memory polynomials and introduce two approaches to

  14. Fluorescent amplified fragment length polymorphism (AFLP ...

    African Journals Online (AJOL)

    Rosa rugosa is an excellent ornamental plant with important ecological, economical and medicinal values in China. Polymorphism amplifications of the genomic DNA of 5 wild R. rugosa accessions and 25 cultivars that originated from China with fluorescent amplified fragment length polymorphism molecular markers were ...

  15. Relationship between morphological and amplified fragment length ...

    African Journals Online (AJOL)

    ... morphological and amplified fragment length polymorphism (AFLP) marker based genetic diversity, to estimate mid parent heterosis and to correlate the estimated parental genetic diversity with heterosis chilli. Five CMS B - lines and 30 testers were used for morphological and AFLP marker genetic divergence analysis.

  16. Random amplified polymorphic DNA (RAPD) marker associated ...

    African Journals Online (AJOL)

    Jane

    2011-06-29

    Jun 29, 2011 ... between the studied provenances were less than 39%. Key words: Acacia Senegal, provenance variation, random amplified polymorphic DNA (RAPD) marker, salt tolerance, seed germination, seedling growth. INTRODUCTION. Salinity is the major factor limiting plants growth, widely spread and has more ...

  17. Random amplified polymorphic DNA (RAPD) marker associated ...

    African Journals Online (AJOL)

    Jane

    2011-06-29

    Jun 29, 2011 ... bands detected were polymorphic for the provenances of A. senegal and the dissimilarity indices between the studied provenances were less than 39%. Key words: Acacia Senegal, provenance variation, random amplified polymorphic DNA (RAPD) marker, salt tolerance, seed germination, seedling growth ...

  18. Optimization of Pr3+:ZBLAN fiber amplifiers

    DEFF Research Database (Denmark)

    Pedersen, B.; Miniscalco, J. W.; Quimby, R. S.

    1992-01-01

    Experimental parameters have been measured and used in a quantitative model of Pr3+-doped fluorozirconate fiber amplifiers. The optimum cutoff wavelength was determined to be 800 nm and the gain for 400 mW of pump was found to increase from 12 to 34 dB if the NA was increased from 0.15 to 0...

  19. Reflected-wave maser. [low noise amplifier

    Science.gov (United States)

    Clauss, R. C. (Inventor)

    1976-01-01

    A number of traveling-wave, slow-wave maser structures, containing active maser material but absent the typical ferrite isolators, are immersed in a nonuniform magnetic field. The microwave signal to be amplified is inserted at a circulator which directs the signal to a slow-wave structure. The signal travels through the slow-wave structure, being amplified according to the distance traveled. The end of the slow-wave structure farthest from the circulator is arranged to be a point of maximum reflection of the signal traveling through the slow-wave structure. As a consequence, the signal to be amplified traverses the slow-wave structure again, in the opposite direction (towards the circulator) experiencing amplification equivalent to that achieved by a conventional traveling-wave maser having twice the length. The circulator directs the amplified signal to following like stages of amplification. Isolators are used in between stages to prevent signals from traveling in the wrong direction, between the stages. Reduced signal loss is experienced at each stage. The high gain produced by each slow-wave structure is reduced to a moderate value by use of a nonuniform magnetic field which also broadens the line width of the maser material. The resulting bandwidth can be exceptionally wide. Cascaded stages provide high gain, exceptionally wide bandwith and very low noise temperature.

  20. Computer-aided design of broad band reflection type amplifiers

    DEFF Research Database (Denmark)

    Hammershaimb, Edgar; Jeppesen, Palle; Schjær-Jacobsen, Hans

    1974-01-01

    . At the same time the impedance of unpackaged devices are obtained by on-line correction for the package parasitics. The microwave circuit chosen is a multiple slug coaxial cavity, that is modelled by sections of lossy transmission lines including step susceptances. The measured small signal impedance......Microwave negative resistance reflection type amplifiers using stable transferred electron devices (TED's) are optimized by numerical optimization techniques programmed for an interactive graphic datascreen. The small signal impedance of packaged TED's is measured on an automatic network analyzer...... of the packaged TED's and the cavity model are used in a direct optimization procedure, in which the calculated minimum gain in the prescribed frequency range is progressively maximized by adjusting the lengths, characteristic impedances and positions of the slugs. The computed results are displayed...

  1. Study of silicon photomultipliers fast amplifier and thermoregulation

    Energy Technology Data Exchange (ETDEWEB)

    D' antone, I. [INFN of Bologna, Viale B.Pichat 4/2, 40127 Bologna (Italy); Fabbri, L.; Foschi, E. [Department of Physics and INFN, Viale B.Pichat 4/2, 40127 Bologna (Italy); Guandalini, C.; Laurenti, G.; Lax, I. [INFN of Bologna, Viale B.Pichat 4/2, 40127 Bologna (Italy); Levi, G.; Quadrani, L.; Sbarra, Ca. [Department of Physics and INFN, Viale B.Pichat 4/2, 40127 Bologna (Italy); Sbarra, Cr., E-mail: cristina.sbarra@bo.infn.i [Department of Physics and INFN, Viale B.Pichat 4/2, 40127 Bologna (Italy); Villa, M.; Zoccoli, A. [Department of Physics and INFN, Viale B.Pichat 4/2, 40127 Bologna (Italy); Zuffa, M. [INFN of Bologna, Viale B.Pichat 4/2, 40127 Bologna (Italy)

    2011-02-21

    The silicon photomultipliers (SiPM) are adopted in various physical applications, from medical physics to astrophysics, for their advantages in terms of cost and weight with respect to traditional photo detectors. Their low bias voltage supply (about 30 V), hardiness and resistance to magnetic field are ideal characteristics for space application. In the frame of INFN-Irst collaboration, some of them have been developed and produced at FBK (Trento-Italy), and have been characterized in the INFN laboratories of Bologna (DaSiPM2 collaboration). The SiPM can be used in conjunction with fibres and counters in high energy physics experiments. To exploit the SiPM time resolution, a fast amplifier has been studied. The SiPM gain depends critically on temperature and a thermal stabilization is also necessary. The use of a thermoelectric cooler module based on a Peltier cell has been investigated, and the results are shown.

  2. Multi-pass amplifier architecture for high power laser systems

    Science.gov (United States)

    Manes, Kenneth R; Spaeth, Mary L; Erlandson, Alvin C

    2014-04-01

    A main amplifier system includes a first reflector operable to receive input light through a first aperture and direct the input light along an optical path. The input light is characterized by a first polarization. The main amplifier system also includes a first polarizer operable to reflect light characterized by the first polarization state. The main amplifier system further includes a first and second set of amplifier modules. Each of the first and second set of amplifier modules includes an entrance window, a quarter wave plate, a plurality of amplifier slablets arrayed substantially parallel to each other, and an exit window. The main amplifier system additionally includes a set of mirrors operable to reflect light exiting the first set of amplifier modules to enter the second set of amplifier modules and a second polarizer operable to reflect light characterized by a second polarization state.

  3. The influence of mild acidity on lysyl-phosphatidylglycerol biosynthesis and lipid membrane physico-chemical properties in methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Rehal, Reg P; Marbach, Helene; Hubbard, Alasdair T M; Sacranie, Anam A; Sebastiani, Federica; Fragneto, Giovanna; Harvey, Richard D

    2017-08-01

    The increased biosynthesis of lysyl-phosphatidylglycerol in Staphylococcus aureus when cultured under conditions of mild acidity and the resultant increased proportion of this lipid in the plasma membrane of the bacterium, alters the physico-chemical properties of lipid bilayers in a manner which is itself dependent upon environmental pH. Clinically relevant strains of S. aureus, both methicillin susceptible and resistant, all exhibited increased lysyl-phosphatidylglycerol biosynthesis in response to mild environmental acidity, albeit to differing degrees, from ∼30% to ∼55% total phospholipid. Polar lipid extracts from these bacteria were analysed by (31)P NMR and reconstituted into vesicles and monolayers, which were characterised by zeta potential measurements and Langmuir isotherms respectively. A combination of increased lysyl-phosphatidylglycerol content and mild environmental acidity were found to synergistically neutralise the charge of the membranes, in one instance altering the zeta potential from -56mV to +21mV, and induce closer packing between the lipids. Challenge of reconstituted S. aureus lipid model membranes by the antimicrobial peptide magainin 2 F5W was examined using monolayer subphase injection and neutron diffraction, and revealed that ionisation of the headgroup α-amine of lysyl-phosphatidylglycerol at pH 5.5, which reduced the magnitude of the peptide-lipid interaction by 80%, was more important for resisting peptide partitioning than increased lipid content alone. The significance of these results is discussed in relation to how colonising mildly acidic environments such as human mucosa may be facilitated by increased lysyl-phosphatidylglycerol biosynthesis and the implications of this for further biophysical analysis of the role of this lipid in bacterial membranes. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Phase-noise reduction in surface wave oscillators by using nonlinear sustaining amplifiers.

    Science.gov (United States)

    Avramov, Ivan D

    2006-04-01

    Nonlinear sustaining amplifier operation has been investigated and applied to high-power negative resistance oscillators (NRO), using single-port surface transverse wave (STW) resonators, and single-transistor sustaining amplifiers for feedback-loop STW oscillators (FLSO) stabilized with two-port STW devices. In all cases, self-limiting, silicon (Si)-bipolar sustaining amplifiers that operate in the highly nonlinear AB-, B-, or C-class modes are implemented. Phase-noise reduction is based on the assumption that a sustaining amplifier, operating in one of these modes, uses current limiting and remains cut off over a significant portion of the wave period. Therefore, it does not generate 1/f noise over the cut-off portion of the radio frequency (RF) cycle, and this reduces the close-in oscillator phase noise significantly. The proposed method has been found to provide phase-noise levels in the -111 to -119 dBc/Hz range at 1 KHz carrier offset in 915 MHz C-class power NRO and FLSO generating up to 23 dBm of RF-power at RF versus dc (RF/dc) efficiencies exceeding 40%. C-class amplifier design techniques are used for adequate matching and high RF/dc efficiency.

  5. The warm, rich sound of valve guitar amplifiers

    Science.gov (United States)

    Keeports, David

    2017-03-01

    Practical solid state diodes and transistors have made glass valve technology nearly obsolete. Nevertheless, valves survive largely because electric guitar players much prefer the sound of valve amplifiers to the sound of transistor amplifiers. This paper discusses the introductory-level physics behind that preference. Overdriving an amplifier adds harmonics to an input sound. While a moderately overdriven valve amplifier produces strong even harmonics that enhance a sound, an overdriven transistor amplifier creates strong odd harmonics that can cause dissonance. The functioning of a triode valve explains its creation of even and odd harmonics. Music production software enables the examination of both the wave shape and the harmonic content of amplified sounds.

  6. Low phase noise oscillator using two parallel connected amplifiers

    Science.gov (United States)

    Kleinberg, Leonard L.

    1987-01-01

    A high frequency oscillator is provided by connecting two amplifier circuits in parallel where each amplifier circuit provides the other amplifier circuit with the conditions necessary for oscillation. The inherent noise present in both amplifier circuits causes the quiescent current, and in turn, the generated frequency, to change. The changes in quiescent current cause the transconductance and the load impedance of each amplifier circuit to vary, and this in turn results in opposing changes in the input susceptance of each amplifier circuit. Because the changes in input susceptance oppose each other, the changes in quiescent current also oppose each other. The net result is that frequency stability is enhanced.

  7. ZrO{sub 2} thin films to improve the chemical resistance of calcium matt glazes; Capas finas de ZrO{sub 2} para mejorar la resistencia quimica de los vidriados mates de calcio

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, M. D.; Mestre, S.; Orts, M. J.; Blasco, E.

    2012-11-01

    The chemical resistance of ceramic glazes susceptible to it, and more specifically the glazes formulated with a calcium matt frit, is enhanced by depositing on the surface a thin layer of zirconium oxide. A stabilized zirconia sol is the precursor of the layer, which is deposited by spray painting over the glaze, and with a mild heat treatment (T{sub m}ax {approx}{approx} 400 degree centigrade) is transformed into ZrO{sub 2} and anchored to the glazes surface. Chemical resistance tests show that the protected glaze does not suffer a visually significant attack by concentrated hydrochloric acid, conditions under which the same glaze without the coating is severely damaged. The used precursor generates a zirconium oxide layer that protects the underlying glaze, so that the chemical attack by the hydrochloric acid is confined to cracks and discontinuities in the deposited layer. (Author) 22 refs.

  8. Class D amplifier for a power piezoelectric load.

    Science.gov (United States)

    Agbossou, K; Dion, J L; Carignan, S; Abdelkrim, M; Cheriti, A

    2000-01-01

    We present a high efficiency inverter (>90%) that can drive an acoustic cavitation reactor with a 2 kW power between 10 and 100 kHz. This reactor is composed of numerous piezoelectric transducers and is particularly used to accelerate various industrial chemical reactions and destroy a variety of organic contaminants in water. The class-D amplifier or inverter is composed of power MOSFETs, type IRFP460, in a full bridge configuration driven by IR2110 circuits in bootstrap mode. The specific nature of the problem comes from the fact that, at frequencies slightly different from a resonant frequency frn, the load is mostly capacitive. The insertion of an appropriate low-pass filter in front of the load allowed an efficient solution to the problem due to the load being capacitive for harmonics. The realized system can provide nearly 2 kW to this type of piezoelectric load, with an efficiency of more than 95%

  9. ytterbium- & erbium-doped silica for planar waveguide lasers & amplifiers

    DEFF Research Database (Denmark)

    Dyndgaard, Morten Glarborg

    2001-01-01

    The purpose of this work was to demonstrate ytterbium doped planar components and investigate the possibilities of making erbium/ytterbium codoped planar waveguides in germano-silica glass. Furthermore, tools for modelling lasers and erbium/ytterbium doped amplifiers. The planar waveguides were...... fabricated using plasma enhanced chemical vapor deposition (PECVD) and reactive ion etching (RIE). These processes and the control of the film composition is discussed. Ytterbium doped planar waveguides are demonstrated, and it is shown that codoping with aluminium has a positive influence...... on the fluorescence intensity of the ytterbium ions. Based on this result ytterbium doped planar waveguides with a net gain of 0.36 dB/cm are made. The glass is sensitive to ultra violet (UV) light, and using UV-writing Bragg gratings are photoimprinted in the waveguides, and a laser is made in a distributed Bragg...

  10. MODELING AND CALCULATION OF FLOW AMPLIFIER PARAMETERS IN STEERING OF HEAVY TRUCKS

    Directory of Open Access Journals (Sweden)

    V. P. Avtushko

    2008-01-01

    Full Text Available The paper analyzes prospects pertaining to development of methods for dynamic calculation of monitoring hydraulic units with various types of relations.  Calculated diagram of steering hydraulic drive with flow amplifier and turning cylinder has been given in the paper and its dynamic model has been developed. A hydraulic drive is considered as a system with lumped parameters. It is supposed that properties of working fluid are unchangeable during transient process; leakages and cavitations do not occur; fluid can be pressed; resistance of service drain line is taken into account. Model has been developed with due account of resistance of manifolds and internal channels of flow amplifier, hydrodynamic forces, that influence on amplifier control valves, and friction forces of movable elements. Multi-variant dynamic calculation has been done and some results of the investigations are presented in the paper. The paper also contains analysis that shows influence of various design and component parameters of flow amplifier on the drive dynamics. 

  11. α--AMYLASES OF Aspergillus flavus var. oryzae AND Bacillus subtilis: THE SUBSTRATE SPECIFICITY AND RESISTANCE TO A NUMBER OF CHEMICALLY ACTIVE SUBSTANCES

    Directory of Open Access Journals (Sweden)

    K. V. Avdiyuk

    2013-06-01

    Full Text Available The ability of Aspergillus flavus var. oryzae 80428 and Bacillus subtilis 147 α-amylases to split different carbohydrate-containing substrates, such as maltose, sucrose, trehalose, dextrin, α- and β-cyclodextrin, amylose, amylopectin, glycogen, pullulan, soluble starch, insoluble starch, corn starch, wheat starch, dextran 500 has been studied. It was shown that investigated enzymes differ by substrate specificity. α-Amylase of A. flavus var. oryzae 80428 rapidly hydrolysed soluble potato and wheat starch, while the α-amylase of B. subtilis 147 — only wheat starch. Both enzymes don’t cleave maltose, α-cyclodextrin and dextran 500. A. flavus var. oryzae 80428 α-amylase display very small ability to hydrolyze pullulan, while α-amylase of B. subtilis 147 it does not act in general. The lowest values of Michaelis constant for both enzymes at splitting of glycogen have been obtained, indicating that enzymes have the greatest affinity to this substrate. The studies of influence of chemically active substances on activity of A. flavus var. oryzae 80428 and B. subtilis 147 ?-amylases show there are resistant to urea, deoxycholic acid, Tween-80, Triton X-100 and hydrogen peroxide. It’s indicate the enzymes tested may be competitive in compare with earlier described in literature enzymes. The obtained results give a possibility to propose in future usage these enzymes in different fields of industry, foremost in detergent industry.

  12. Chemical composition, antioxidant activity and in vitro antibacterial activity of Achillea wilhelmsii C. Koch essential oil on methicillin-susceptible and methicillin-resistant Staphylococcus aureus spp.

    Science.gov (United States)

    Alfatemi, Seyedeh Mahsan Hoseini; Rad, Javad Sharifi; Rad, Majid Sharifi; Mohsenzadeh, Sasan; da Silva, Jaime A Teixeira

    2015-02-01

    The present study investigated the chemical composition of the essential oil (EO) from aerial parts (flowering stage) of Achillea wilhelmsii C. Koch by GC-MS. In addition, the antioxidant activity of the EO as well as its antimicrobial activity against methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MRSA) strains was tested. Antioxidant activity was measured by the ability of the EO to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals while the antimicrobial activity was assessed by the disc-diffusion method. In total, 52 compounds were recognized, accounting for 97.33 % of the EO. The main compounds in the EO were carvacrol (22.49 %), dihydrocarvone (13.23 %), linalool (12 %), 1,8-cineol (11.42 %), camphene (8.31 %), thymol (5.28 %), camphor (3.71 %), pulegone (2.82 %) α-terpineol (2.11 %), bornyl acetate (1.14 %), and farganol (1.01 %). The EC 50 value of the EO was 0.01 and 0.08 mg/mL for the antioxidant and DPPH-scavenging ability, respectively. A. wilhelmsii EO affected methicillin-sensitive Staphylococcus aureus (MSSA) and MRSA, but the impact was more effective on MSSA.

  13. Evaluation of chemical and mechanical resistance of virgin and recycled poly (ethylene terephthalate and poly(methylene oxide when applied as gravel pack in petroleum wells

    Directory of Open Access Journals (Sweden)

    Alexandre Zacarias Ignácio Pereira

    2015-08-01

    Full Text Available AbstractNowadays more and more unexpected uses for common materials have been observed, especially when recycled polymers are concerned. In this work, the viability for application of virgin and recycled poly(ethylene terephthalate (PETvir and PETrec, respectively and also poly(methylene oxide (PMO as granular materials (gravel for gravel packing in sand control systems for unconsolidated sandstone reservoirs was studied. Polymer samples were tested in conditions similar to those observed in Campos Basin sandstone formations, in Brazilian Southwest (70 °C and 24.1 MPa. Samples were individually confined in roller cells with chemicals used in formation treatment: hydrochloric acid, pentapotassic DTPA salt (chelant Trilon CK and in a mixture of diesel, xylene and butyl glycol. Mass loss was measured and the changes in molecular mass verified by size exclusion chromatography (SEC. Physical shape and grain size distribution were verified by scanning electron microscopy (SEM and sieving tests. The effects over the polymeric gravel pack confinement resistance and permeability were evaluated using an API permeability cell. PMO proved to have a limited use, whereas PETrec and PETvir samples were not significantly affected, suggesting the viability of applying that recycled polymer in gravel packing for sand control in petroleum wells.

  14. Synthesis and characterization of sintering-resistant silica-encapsulated Fe3O4 magnetic nanoparticles active for oxidation and chemical looping combustion

    Science.gov (United States)

    Park, Jung-Nam; Zhang, Peng; Hu, Yong-Sheng; McFarland, Eric W.

    2010-06-01

    A nanocomposite catalyst composed of ferromagnetic magnetite cores (15.5 ± 2.0 nm) and silica shells with a thickness of 4.5 ± 1.0 nm (Fe3O4@SiO2) was prepared by a two-step microemulsion-based synthesis. X-ray photoelectron spectroscopy and Raman spectroscopy after oxidation support the presence of a stable Fe3O4 core and a surface phase of γ-Fe2O3. The nanocomposite structure exhibited 100% conversion of CO in oxygen at a residence time of 0.1 s at 310 °C. When pre-oxidized, the Fe3O4@SiO2 catalyst is shown to be a suitable solid oxygen carrier for chemical looping combustion of methane at 700 °C. The nanocomposites retain their magnetism following the reaction which provides the potential for use of magnetic separation and capture in moving bed reactor applications. The core magnetite within the silica shell is resistant to sintering and a bulk phase transition to temperatures as high as 700 °C. These catalysts can be of use in applications of high temperature applications where catalyst recovery by magnetic separation may be required.

  15. Reduction of PCR-amplifiable DNA by ethylene oxide treatment of forensic consumables.

    Science.gov (United States)

    Neureuther, Katharina; Rohmann, Edyta; Hilken, Manuela; Sonntag, Marie-Luise; Herdt, Silke; Koennecke, Thomas; Jacobs, Roland; Adamski, Michalina; Reisbacher, Stefan; Alfs, Knut; Strain, Peter; Bastisch, Ingo

    2014-09-01

    A reliable method to provide molecular biology products free of contaminating DNA is of forensic interest. Ethylene oxide (EO) treatment has been demonstrated as an effective method in published studies. This study aimed to address some additional experiments that are closer to forensic practice. In the first part of this study, different consumables such as cotton swabs, latex gloves and micro test tubes were spiked with saliva, blood and skin cells to mimic a real-life contamination scenario. EO treatment was performed for a period of 3, 5, 7, and 10h, respectively. For comparison, gamma and electron beam treatment was applied. In the second part of this study, a cell culture line (K562) was used to apply defined cell counts on cotton swabs followed by EO treatment for 3 and 5h. After extraction of samples, the DNA content was quantified using a real-time PCR based system. STR analysis was performed using a latest generation STR kit to meet current sensitivity limits. A good correlation of real-time PCR results and STR results was observed. This work confirmed the findings of earlier studies showing that chemical EO treatment is much more successful in reducing the amount of PCR-amplifiable DNA than ionising radiation. Furthermore, the efficacy of EO treatment is affected by the nature of the samples. DNA in saliva was more susceptible to damage by EO gas than DNA in blood. Our results show, that accessibility of the sample to EO gas has a strong influence on the method's efficiency. While treatment of samples on cotton swabs packed into gas-permeable bags was very successful, samples inside a closed micro test tube were resistant to the same treatment conditions. Our work with defined K562 cell numbers and multi-copy quantitative PCR could show that a 5h EO treatment results in a 10(5) fold reduction of PCR-amplifiable DNA. Corresponding STR-PCR results also show only sporadic allele calls in the Mini-loci range, providing a reliable interpretation of forensic

  16. High gain, multiatmosphere CO2 laser amplifier

    Science.gov (United States)

    Stuart, G. C.; Houtman, H.; Meyer, J.

    1987-02-01

    A novel TE discharge, 15-mm aperture, multiatmosphere, CO2 laser amplifier is described, with measured electrical characteristics and gain measurements on the 9.294-micron, 9R (16) line. The electrical circuit used in this amplifier is a realistic alternative to the Marx bank or conventional LC inversion circuit and, similarly, it would be useful for excitation of other gas lasers as well. This automatically preionized, double-sided, fourfold LC inversion circuit uses only one spark gap, and it is shown to provide small-signal gains of 5.7 percent/cm, at 120 J/l atm and 10 atm. The generalization to an n-stage device, which would be suitable for higher pressures, and larger apertures, is discussed.

  17. Amplified music exposure carries risks to hearing.

    Science.gov (United States)

    da Silva, Valéria Gomes; de Oliveira, Carlos Augusto Costa Pires; Tauil, Pedro Luíz; de Castro Silva, Isabella Monteiro; Sampaio, André Luiz Lopes

    2017-02-01

    To investigate the association between changes in the outer hair cells and exposure to amplified music in a group of high-school students. In this retrospective, case-control study, 86 subjects underwent audiometry, immittance audiometry, and distortion-product otoacoustic emission tests. The subjects were questioned about their listening habits and divided into 2 groups: exposed and unexposed. Most of the subjects had reduced function in their outer hair cells, mainly beginning at 8 kHz. Among 60 subjects-30 cases and 30 controls-75% were considered exposed and 25% unexposed. The exposed subjects were 9.33 times more likely to have altered outer hair cells than the unexposed subjects were. Exposure to amplified music is associated with reduced function in the hair cells. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  18. Noise Gain Features of Fiber Raman Amplifier

    Directory of Open Access Journals (Sweden)

    Georgii S. Felinskyi

    2016-01-01

    Full Text Available The formation dynamics of the optical noise in a silica single mode fiber (SMF as function of the pump power variation in the counter pumped fiber Raman amplifier (FRA is experimentally studied. The ratio between the power of amplified spontaneous emission and the power of incoherent optical noise is quantitatively determined by detailed analysis of experimental data in the pump powers range of 100–300 mW within the full band of Stokes frequencies, including FRA working wavelengths over the C + L transparency windows. It is found out the maximum of Raman gain coefficient for optical noise does not exceed ~60% of corresponding peak at the gain profile maximum of coherent signal. It is shown that the real FRA noise figure may be considerably less than 3 dB over a wide wavelength range (100 nm at a pump power of several hundreds of mW.

  19. Cryogenic cooling for high power laser amplifiers

    Directory of Open Access Journals (Sweden)

    Perin J.P.

    2013-11-01

    Full Text Available Using DPSSL (Diode Pumped Solid State Lasers as pumping technology, PW-class lasers with enhanced repetition rates are developed. Each of the Yb YAG amplifiers will be diode-pumped at a wavelength of 940 nm. This is a prerequisite for achieving high repetition rates (light amplification duration 1 millisecond and repetition rate 10 Hz. The efficiency of DPSSL is inversely proportional to the temperature, for this reason the slab amplifier have to be cooled at a temperature in the range of 100 K–170 K with a heat flux of 1 MW*m−2. This paper describes the thermo-mechanical analysis for the design of the amplification laser head, presents a preliminary proposal for the required cryogenic cooling system and finally outlines the gain of cryogenic operation for the efficiency of high pulsed laser.

  20. SINGLE CONVERSION ISOLATED IMPEDANCE TRANSFORMATION AMPLIFIER

    DEFF Research Database (Denmark)

    2003-01-01

    The invention relates to a switch mode power amplifier. A first and a second change-over switch are inserted between a DC voltage supply and a primary side of an isolation transformer. Two secondary windings are connected to a power output terminal. A first and a second secondary side power switch...... are adapted to connect the two secondary windings to the power connector of the power output terminal. The pulse width modulation means is adapted to generate control signals for the driver means of the first and the second change-over switch so as to cause every second pulse to be inverted. The pulse width...... modulation means is also adapted to generate a third and a fourth control signal for said driver means of the power switches of said first and said second secondary. The invention also relates to a method of controlling a switch mode power amplifier...

  1. A SIMULATION OF 450MHz AMPLIFIER WITH DISTRIBUTED ...

    African Journals Online (AJOL)

    DR. AMINU

    USING BIPOLAR JUNCTION TRANSISTOR FROM NI- CIRCUIT DESIGN ... amplifier and multistage distributed amplifier is carried out. In this ... namely, bandwidth, signal power and noise are the .... and Engineers', Prentice-Hall International.

  2. Reconfigurable Josephson Circulator/Directional Amplifier

    Directory of Open Access Journals (Sweden)

    K. M. Sliwa

    2015-11-01

    Full Text Available Circulators and directional amplifiers are crucial nonreciprocal signal routing and processing components involved in microwave read-out chains for a variety of applications. They are particularly important in the field of superconducting quantum information, where the devices also need to have minimal photon losses to preserve the quantum coherence of signals. Conventional commercial implementations of each device suffer from losses and are built from very different physical principles, which has led to separate strategies for the construction of their quantum-limited versions. However, as recently theoretically, by establishing simultaneous pairwise conversion and/or gain processes between three modes of a Josephson-junction-based superconducting microwave circuit, it is possible to endow the circuit with the functions of either a phase-preserving directional amplifier or a circulator. Here, we experimentally demonstrate these two modes of operation of the same circuit. Furthermore, in the directional amplifier mode, we show that the noise performance is comparable to standard nondirectional superconducting amplifiers, while in the circulator mode, we show that the sense of circulation is fully reversible. Our device is far simpler in both modes of operation than previous proposals and implementations, requiring only three microwave pumps. It offers the advantage of flexibility, as it can dynamically switch between modes of operation as its pump conditions are changed. Moreover, by demonstrating that a single three-wave process yields nonreciprocal devices with reconfigurable functions, our work breaks the ground for the development of future, more complex directional circuits, and has excellent prospects for on-chip integration.

  3. Amplifying the Hawking Signal in BECs

    Directory of Open Access Journals (Sweden)

    Roberto Balbinot

    2014-01-01

    Full Text Available We consider simple models of Bose-Einstein condensates to study analog pair-creation effects, namely, the Hawking effect from acoustic black holes and the dynamical Casimir effect in rapidly time-dependent backgrounds. We also focus on a proposal by Cornell to amplify the Hawking signal in density-density correlators by reducing the atoms’ interactions shortly before measurements are made.

  4. Fast Electrocardiogram Amplifier Recovery after Defibrillation Shock

    Directory of Open Access Journals (Sweden)

    Ivan Dotsinsky

    2005-04-01

    Full Text Available A procedure for fast ECG amplifier recovery after defibrillation shocks was developed and simulated in the MATLAB environment. Exponentially decaying post-shock voltages have been recorded. Signals from the AHA database are taken and mixed with the recorded exponential disturbances. The algorithm applies moving averaging (comb filter on the compound input signal, thereby obtaining the samples of the disturbance. They are currently subtracted from the input signal. The results obtained show that its recovery is practically instantaneous.

  5. Ultra-low Voltage CMOS Cascode Amplifier

    DEFF Research Database (Denmark)

    Lehmann, Torsten; Cassia, Marco

    2000-01-01

    In this paper, we design a folded cascode operational transconductance amplifier in a standard CMOS process, which has a measured 69 dB DC gain, a 2 MHz bandwidth and compatible input- and output voltage levels at a 1 V power supply. This is done by a novel Current Driven Bulk (CDB) technique......, which reduces the MOST threshold voltage by forcing a constant current though the transistor bulk terminal. We also look at limitations and improvements of this CDB technique....

  6. Predistortion for Nonlinear Power Amplifiers with Memory

    OpenAIRE

    Nizamuddin, Muhammad Ali

    2002-01-01

    The fusion of voice and data applications, along with the demand for high data-rate applications such as video-on-demand, is making radio frequency (RF) spectrum an increasingly expensive commodity for current and future communications. Although bandwidth-efficient digital modulation alleviates part of the problem by requiring a minimal use of spectral resources, they put an extra design burden on RF engineers. RF transmitters and power amplifiers account for more t...

  7. Self-amplifying mRNA vaccines.

    Science.gov (United States)

    Brito, Luis A; Kommareddy, Sushma; Maione, Domenico; Uematsu, Yasushi; Giovani, Cinzia; Berlanda Scorza, Francesco; Otten, Gillis R; Yu, Dong; Mandl, Christian W; Mason, Peter W; Dormitzer, Philip R; Ulmer, Jeffrey B; Geall, Andrew J

    2015-01-01

    This chapter provides a brief introduction to nucleic acid-based vaccines and recent research in developing self-amplifying mRNA vaccines. These vaccines promise the flexibility of plasmid DNA vaccines with enhanced immunogenicity and safety. The key to realizing the full potential of these vaccines is efficient delivery of nucleic acid to the cytoplasm of a cell, where it can amplify and express the encoded antigenic protein. The hydrophilicity and strong net negative charge of RNA impedes cellular uptake. To overcome this limitation, electrostatic complexation with cationic lipids or polymers and physical delivery using electroporation or ballistic particles to improve cellular uptake has been evaluated. This chapter highlights the rapid progress made in using nonviral delivery systems for RNA-based vaccines. Initial preclinical testing of self-amplifying mRNA vaccines has shown nonviral delivery to be capable of producing potent and robust innate and adaptive immune responses in small animals and nonhuman primates. Historically, the prospect of developing mRNA vaccines was uncertain due to concerns of mRNA instability and the feasibility of large-scale manufacturing. Today, these issues are no longer perceived as barriers in the widespread implementation of the technology. Currently, nonamplifying mRNA vaccines are under investigation in human clinical trials and can be produced at a sufficient quantity and quality to meet regulatory requirements. If the encouraging preclinical data with self-amplifying mRNA vaccines are matched by equivalently positive immunogenicity, potency, and tolerability in human trials, this platform could establish nucleic acid vaccines as a versatile new tool for human immunization. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. CHARACTERIZATION OF COMMERCIALLY AVAILABLE ALKALI RESISTANT GLASS FIBER FOR CONCRETE REINFORCEMENT AND CHEMICAL DURABILITY COMPARISON WITH SrO-Mn2O3-Fe2O3-MgO-ZrO2-SiO2 (SMFMZS SYSTEM GLASSES

    Directory of Open Access Journals (Sweden)

    Göktuğ GÜNKAYA

    2012-12-01

    Full Text Available According to the relevant literature, the utilization of different kind of glass fibers in concrete introduces positive effect on the mechanical behavior, especially toughness. There are many glassfibers available to reinforce concretes. Glass fiber composition is so important because it may change the properties such as strength, elastic modulus and alkali resistance. Its most important property to be used in concrete is the alkali resistance. Some glasses of SrO–MgO–ZrO2–SiO2 (SMZS quaternary system, such as 26SrO, 20MgO, 14ZrO2, 40SiO2 (Zrn glass, have been found to be highly alkali resistant thanks to their high ZrO2 and MgO contents. Previous researches on these glasses with MnO and/or Fe2O3 partially replacing SrO have been made with the aim of improving the chemical resistance and decreasing the production cost.The main target of the present study, first of all, was to characterize commercially available alkali resistant glass fiber for concrete reinforcement and then to compare its alkali durability with those of the SrO-Mn2O3-Fe2O3-MgO-ZrO2-SiO2 (SMFMZS system glasses. For such purposes, XRF, Tg-DTA, alkali resistance tests and SEM analysis conducted with EDX were employed. According tothe alkali endurance test results it was revealed that some of the SMFMZS system glass powders are 10 times resistant to alkali environments than the commercial glass fibers used in this study.Therefore, they can be considered as alternative filling materials on the evolution of chemically resistant concrete structures.

  9. Charge sensitive amplifies. The state of arts

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Kunishiro [Clear Pulse Co., Tokyo (Japan)

    1996-07-01

    In the radiation detectors, signals are essentially brought with charges produced by radiation, then it is naturally the best way to use a charge sensitive amplifier (CSA) system to extract those signals. The CSA is thought to be the best amplifier suitable to almost all the radiation detectors, if neglecting economical points of view. The CSA has been only applied to special fields like radiation detection because the concept of `charges` is not so universal against the concepts of `voltage` and `current`. The CSA, however, is low in noise and a high speed amplifier and may be applicable not only to radiation measurement but also piezoelectric devices and also bolometers. In this article, noise in the CSA, basic circuit on the CSA, concepts of `equivalent noise charge` (ENC), a method for the ENC, and importance of the `open-loop gain` in the CSA to achieve better performance of it and how to realize in a practical CSA were described. And, characteristics on a counting rate of the CSA, various circuit used in the CSA, and CSAs which are commercially available at present and special purpose CSAs were also introduced. (G.K.)

  10. A 205GHz Amplifier in 90nm CMOS Technology

    Science.gov (United States)

    2017-03-01

    A 205GHz Amplifier in 90nm CMOS Technology Shahab Ardalan, Senior Member, IEEE Electrical Department, Charles W. Davidson College of Engineering...greater CMOS technologies . Keywords: Amplifier, neutralization, parasitic, Psat, P1dB.   Introduction Millimeter-wave and sub-mm-wave (THz band...amplifier has been implemented and fabricated in 90nm CMOS technology . The proposed amplifier attained a gain of 10.5 dB whilst consuming a dc power

  11. Noise and saturation properties of semiconductor quantum dot optical amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper

    2002-01-01

    We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved.......We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved....

  12. Pump to signal noise transfer in parametric fiber amplifiers

    DEFF Research Database (Denmark)

    Lund-Hansen, Toke; Rottwitt, Karsten; Peucheret, Christophe

    2010-01-01

    Fiber optic parametric amplifiers have been suggested due to their potential low spontaneous emission. However, by nature the parametric amplifier only work in a forward pumped configuration, which result in transfer of relative intensity noise in the pump to the signal.......Fiber optic parametric amplifiers have been suggested due to their potential low spontaneous emission. However, by nature the parametric amplifier only work in a forward pumped configuration, which result in transfer of relative intensity noise in the pump to the signal....

  13. Exploration of Single-Chip Phase-Sensitive Amplifiers

    Science.gov (United States)

    2015-11-05

    PERCENT_SUPPORTEDNAME FTE Equivalent: Total Number: ...... ...... Inventions (DD882) Scientific Progress First single -chip photonic integrated phase -sensitive amplifier...Sep-2015 Approved for Public Release; Distribution Unlimited Final Report: Exploration of Single -Chip Phase -Sensitive Amplifiers The views, opinions...published in non peer-reviewed journals: Final Report: Exploration of Single -Chip Phase -Sensitive Amplifiers Report Title A monolithically integrated

  14. The Use of Cryogenic HEMT Amplifiers in Wide Band Radiometers

    OpenAIRE

    Jarosik, Norman

    2000-01-01

    Advances in device fabrication, modelling and design techniques have made wide band, low noise cryogenic amplifiers available at frequencies up to 106 GHz. Microwave radiometry applications as used in radio astronomy capitalize on the low noise and large bandwidths of these amplifiers. Radiometers must be carefully designed so as to preclude sensitivity degradations caused by small, low frequency gain fluctuations inherent in these amplifiers.

  15. Chemical and Biological Resistant Clothing

    Science.gov (United States)

    2013-04-01

    for DMMP Measurement (Data from Samples with and without the Addition of Particulate Zeolite Sorbents...types, including styrenic, acrylic, methacrylic, hydrophobic and low-surface-energy monomers; it is also highly tolerant of functional groups. This...type and location of ionic/hydrophilic and hydrophobic blocks, and block volume fractions. Given the endless number of possible BCP architectures

  16. Chemical Countermeasures for Antibiotic Resistance

    Science.gov (United States)

    2014-04-01

    been carried out by measuring the hemolytic activity. Defibrinated sheep blood cells suspended in PBS was exposed to various concentrations of...compounds.14 These compounds are being evaluated by the Cavanagh lab in a Caenorhabditis elegans fecundity assay to observe the reproductive effects of

  17. A low-voltage sense amplifier with two-stage operational amplifier clamping for flash memory

    Science.gov (United States)

    Guo, Jiarong

    2017-04-01

    A low-voltage sense amplifier with reference current generator utilizing two-stage operational amplifier clamp structure for flash memory is presented in this paper, capable of operating with minimum supply voltage at 1 V. A new reference current generation circuit composed of a reference cell and a two-stage operational amplifier clamping the drain pole of the reference cell is used to generate the reference current, which avoids the threshold limitation caused by current mirror transistor in the traditional sense amplifier. A novel reference voltage generation circuit using dummy bit-line structure without pull-down current is also adopted, which not only improves the sense window enhancing read precision but also saves power consumption. The sense amplifier was implemented in a flash realized in 90 nm flash technology. Experimental results show the access time is 14.7 ns with power supply of 1.2 V and slow corner at 125 °C. Project supported by the National Natural Science Fundation of China (No. 61376028).

  18. ISR meets SAR outside: additive action of the endophyte Bacillus pumilus INR7 and the chemical inducer, benzothiadiazole, on induced resistance against bacterial spot in field-grown pepper.

    Science.gov (United States)

    Yi, Hwe-Su; Yang, Jung Wook; Ryu, Choong-Min

    2013-01-01

    Induced resistance has been recognized as an attractive tool for plant disease management in modern agriculture. During the last two decades, studies on chemically- and biologically elicited induced resistance have revealed previously unknown features of the plant defense response including defense priming. As a biological trigger for induced resistance, plant growth-promoting rhizobacteria (PGPR) are a group of root-associated bacteria that can reduce plant disease severity and incidence, and augment plant growth and yield under greenhouse and field conditions. We evaluated the potential of an endophytic PGPR, Bacillus pumilus INR7, to induce systemic resistance against bacterial spot caused by Xanthomonas axonopodis pv. vesicatoria in pepper. Trials in the greenhouse showed significantly less symptom development in pepper plants inoculated with strain INR7 compared to a water treatment. Furthermore, a single dipping treatment with INR7 before transplantation of pepper plants into the field elicited an induced systemic resistance response against bacterial spot caused by artificially infiltration of X. axonopodis pv. vesicatoria and even against naturally occurring bacterial spot disease. We identified an additive effect on induced resistance after administration of a combination treatment composed of strain INR7 with a chemical inducer, benzothiadiazole (BTH) in the field. The combination treatment stimulated expression of pepper defense marker genes CaPR1, CaTin1, and CaPR4 to a greater extent than did treatment with either agent alone. Similar experiments conducted with tobacco revealed no additive effects under field conditions. Interestingly, co-application of plants with INR7 lifted the growth repressing effect of BTH. Application of BTH onto pepper and tobacco did not affect rhizosphere colonization but supported a higher population density inside plant roots when compared to water-treated control plants. Our results indicate that PGPR can be used in

  19. Analysis of multipass laser amplifier systems for storage laser media

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, J.F.

    1980-03-25

    The performance characteristics of single pass and multipass storage laser amplifiers are presented and compared. The effects of the multipass amplifier parameters on the extraction characteristics are examined. For a wide range of conditions the multipass amplifier is found to provide high energy gain and high efficiency simultaneously. This is a significant advantage over the single pass laser amplifier. Finally, three specific storage laser amplifier systems, flashlamp pumped V:MgF/sub 2/, XeF laser pumped Tm:Glass, and photolytically pumped Selenium, are examined. The performance characteristics for each of the three systems are calculated and compared.

  20. Simultaneous efficient removal of high-strength ammonia nitrogen and chemical oxygen demand from landfill leachate by using an extremely high ammonia nitrogen-resistant strain.

    Science.gov (United States)

    Yu, Dahai; Yang, Jiyu; Fang, Xuexun; Ren, Hejun

    2015-01-01

    Bioaugmentation is a promising technology for pollutant elimination from stressed environments, and it would provide an efficient way to solve challenges in traditional biotreatment of wastewater with high strength of ammonia nitrogen (NH4(+)-N). A high NH4(+)-N-resistant bacteria strain, identified as Bacillus cereus (Jlu BC), was domesticated and isolated from the bacteria consortium in landfill leachate. Jlu BC could survive in 100 g/L NH4(+)-N environment, which indicated its extremely high NH4(+)-N tolerance than the stains found before. Jlu BC was employed in the bioaugmented system to remove high strength of NH4(+)-N from landfill leachate, and to increase the removal efficiency, response surface methodology (RSM) was used for optimizing bioaugmentation degradation conditions. At the optimum condition (initial pH 7.33, 4.14 days, initial chemical oxygen demand [COD] concentration [18,000 mg/L], 3.5 mL inoculated domesticated bacteria strain, 0.3 mg/mL phosphorus supplement, 30 °C, and 170 rpm), 94.74 ± 3.8% removal rate of NH4(+)-N was obtained, and the experiment data corresponded well with the predicted removal rate of the RSM models (95.50%). Furthermore, COD removal rate of 81.94 ± 1.4% was obtained simultaneously. The results presented are promising, and the screened strain would be of great practical importance in mature landfill leachate and other NH4(+)-N enrichment wastewater pollution control. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

  1. Development of 6H-SiC CMOS Transistors for Insertion into a 350 deg C Operational Amplifier

    Science.gov (United States)

    1992-05-15

    epitaxial thickness in order to reduce the off- resistance associated with the NMOS device while maintaining breakdown reliability of the PMOS device...in Fig. 4. A variety of parameters are being recorded, including threshold voltage, transconductance, output resistance , and effect of substrate bias...operational amplifier ( opamp ) using the models developed for the silicon carbide transistors. Two of the three process approaches proposed above will

  2. Class D audio amplifiers for high voltage capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis

    Audio reproduction systems contains two key components, the amplifier and the loudspeaker. In the last 20 – 30 years the technology of audio amplifiers have performed a fundamental shift of paradigm. Class D audio amplifiers have replaced the linear amplifiers, suffering from the well-known issues...... of high volume, weight, and cost. High efficient class D amplifiers are now widely available offering power densities, that their linear counterparts can not match. Unlike the technology of audio amplifiers, the loudspeaker is still based on the traditional electrodynamic transducer invented by C.W. Rice......-of-the-art for class D audio amplifiers driving the electrodynamic transducer is presented. Chapter 3 gives an introduction to the DEAP transducer as a load in loudspeaker systems. The main purpose being to established the frequency response of the DEAP input impedance, but also investigate the large signal...

  3. Envelope tracking CMOS power amplifier with high-speed CMOS envelope amplifier for mobile handsets

    Science.gov (United States)

    Yoshida, Eiji; Sakai, Yasufumi; Oishi, Kazuaki; Yamazaki, Hiroshi; Mori, Toshihiko; Yamaura, Shinji; Suto, Kazuo; Tanaka, Tetsu

    2014-01-01

    A high-efficiency CMOS power amplifier (PA) based on envelope tracking (ET) has been reported for a wideband code division multiple access (W-CDMA) and long term evolution (LTE) application. By adopting a high-speed CMOS envelope amplifier with current direction sensing, a 5% improvement in total power-added efficiency (PAE) and a 11 dB decrease in adjacent channel leakage ratio (ACLR) are achieved with a W-CDMA signal. Moreover, the proposed PA achieves a PAE of 25.4% for a 10 MHz LTE signal at an output power (Pout) of 25.6 dBm and a gain of 24 dB.

  4. EMG amplifier with wireless data transmission

    Science.gov (United States)

    Kowalski, Grzegorz; Wildner, Krzysztof

    2017-08-01

    Wireless medical diagnostics is a trend in modern technology used in medicine. This paper presents a concept of realization, architecture of hardware and software implementation of an elecromyography signal (EMG) amplifier with wireless data transmission. This amplifier consists of three components: analogue processing of bioelectric signal module, micro-controller circuit and an application enabling data acquisition via a personal computer. The analogue bioelectric signal processing circuit receives electromyography signals from the skin surface, followed by initial analogue processing and preparation of the signals for further digital processing. The second module is a micro-controller circuit designed to wirelessly transmit the electromyography signals from the analogue signal converter to a personal computer. Its purpose is to eliminate the need for wired connections between the patient and the data logging device. The third block is a computer application designed to display the transmitted electromyography signals, as well as data capture and analysis. Its purpose is to provide a graphical representation of the collected data. The entire device has been thoroughly tested to ensure proper functioning. In use, the device displayed the captured electromyography signal from the arm of the patient. Amplitude- frequency characteristics were set in order to investigate the bandwidth and the overall gain of the device.

  5. Quantum dots for lasers, amplifiers and computing

    Energy Technology Data Exchange (ETDEWEB)

    Bimberg, Dieter [Technische Universitaet Berlin, Hardenbergstr. 36, 10623, Berlin (Germany)

    2005-07-07

    For InAs-GaAs based quantum dot lasers emitting at 1300 nm, digital modulation showing an open eye pattern up to 12 Gb s{sup -1} at room temperature is demonstrated, at 10 Gb s{sup -1} the bit error rate is below 10{sup -12} at -2 dB m receiver power. Cut-off frequencies up to 20 GHz are realised for lasers emitting at 1.1 {mu}m. Passively mode-locked QD lasers generate optical pulses with repetition frequencies between 5 and 50 GHz, with a minimum Fourier limited pulse length of 3 ps. The uncorrelated jitter is below 1 ps. We use here deeply etched narrow ridge waveguide structures which show excellent performance similar to shallow mesa structures, but a circular far field at a ridge width of 1 {mu}m, improving coupling efficiency into fibres. No beam filamentation of the fundamental mode, low a-factors and strongly reduced sensitivity to optical feedback are observed. QD lasers are thus superior to QW lasers for any system or network. Quantum dot semiconductor optical amplifier (QD SOAs) demonstrate gain recovery times of 120-140 fs, 4-7 times faster than bulk/QW SOAs, and a net gain larger than 0.4 dB/(mm*QD-layer) providing us with novel types of booster amplifiers and Mach-Zehnder interferometers. These breakthroughs became possible due to systematic development of self-organized growth technologies.

  6. Discretization analysis of bifurcation based nonlinear amplifiers

    Directory of Open Access Journals (Sweden)

    S. Feldkord

    2017-09-01

    Full Text Available Recently, for modeling biological amplification processes, nonlinear amplifiers based on the supercritical Andronov–Hopf bifurcation have been widely analyzed analytically. For technical realizations, digital systems have become the most relevant systems in signal processing applications. The underlying continuous-time systems are transferred to the discrete-time domain using numerical integration methods. Within this contribution, effects on the qualitative behavior of the Andronov–Hopf bifurcation based systems concerning numerical integration methods are analyzed. It is shown exemplarily that explicit Runge–Kutta methods transform the truncated normalform equation of the Andronov–Hopf bifurcation into the normalform equation of the Neimark–Sacker bifurcation. Dependent on the order of the integration method, higher order terms are added during this transformation.A rescaled normalform equation of the Neimark–Sacker bifurcation is introduced that allows a parametric design of a discrete-time system which corresponds to the rescaled Andronov–Hopf system. This system approximates the characteristics of the rescaled Hopf-type amplifier for a large range of parameters. The natural frequency and the peak amplitude are preserved for every set of parameters. The Neimark–Sacker bifurcation based systems avoid large computational effort that would be caused by applying higher order integration methods to the continuous-time normalform equations.

  7. Silicon on insulator MESFETs for RF amplifiers

    Science.gov (United States)

    Wilk, Seth J.; Balijepalli, Asha; Ervin, Joseph; Lepkowski, William; Thornton, Trevor J.

    2010-03-01

    CMOS compatible, high voltage SOI MESFETs have been fabricated using a standard 3.3 V CMOS process without any changes to the process flow. A 0.6 μm gate length device operates with a cut-off frequency of 7.3 GHz and a maximum oscillation frequency of 21 GHz. There is no degradation in device performance up to its breakdown voltage, which greatly exceeds that of CMOS devices on the same process. Other figures-of-merit of relevance to RF front-end design are presented, including the maximum stable gain and noise figure. An accurate representation of the device in SPICE has been developed using the commercially available TOM3 model. Using the SOI MESFET model, a source degenerated low noise RF amplifier targeting operation near 1 GHz has been designed. The amplifier was fabricated on a PCB board and operates at 940 MHz with a minimum NF of 3.8 dB and RF gain of 9.9 dB while only consuming 5mW of DC power.

  8. Discretization analysis of bifurcation based nonlinear amplifiers

    Science.gov (United States)

    Feldkord, Sven; Reit, Marco; Mathis, Wolfgang

    2017-09-01

    Recently, for modeling biological amplification processes, nonlinear amplifiers based on the supercritical Andronov-Hopf bifurcation have been widely analyzed analytically. For technical realizations, digital systems have become the most relevant systems in signal processing applications. The underlying continuous-time systems are transferred to the discrete-time domain using numerical integration methods. Within this contribution, effects on the qualitative behavior of the Andronov-Hopf bifurcation based systems concerning numerical integration methods are analyzed. It is shown exemplarily that explicit Runge-Kutta methods transform the truncated normalform equation of the Andronov-Hopf bifurcation into the normalform equation of the Neimark-Sacker bifurcation. Dependent on the order of the integration method, higher order terms are added during this transformation.A rescaled normalform equation of the Neimark-Sacker bifurcation is introduced that allows a parametric design of a discrete-time system which corresponds to the rescaled Andronov-Hopf system. This system approximates the characteristics of the rescaled Hopf-type amplifier for a large range of parameters. The natural frequency and the peak amplitude are preserved for every set of parameters. The Neimark-Sacker bifurcation based systems avoid large computational effort that would be caused by applying higher order integration methods to the continuous-time normalform equations.

  9. ISR meets SAR outside: Additive action of the endophyte Bacillus pumilus INR7 and the chemical inducer, benzothiadiazole, on induced resistance against bacterial spot in field-grown pepper

    Directory of Open Access Journals (Sweden)

    Hwe-Su eYi

    2013-05-01

    Full Text Available Induced resistance has been recognised as an attractive tool for plant disease management in modern agriculture. During the last two decades, studies on chemically- and biologically-elicited induced resistance have revealed previously unknown features of the plant defence response including defence priming. As a biological trigger for induced resistance, plant growth-promoting rhizobacteria (PGPR are a group of root-associated bacteria that can reduce plant disease severity and incidence, and augment plant growth and yield under greenhouse and field conditions. We evaluated the potential of an endophytic PGPR, Bacillus pumilus INR7, to induce systemic resistance against bacterial spot caused by Xanthomonas axonopodis pv. vesicatoria in pepper. Trials in the greenhouse showed significantly less symptom development in pepper plants inoculated with strain INR7 compared to a water treatment. Furthermore, a single dipping treatment with INR7 before transplantation of pepper plants into the field elicited an induced systemic resistance (ISR response against bacterial spot caused by artificially infiltration of X. axonopodis pv. vesicatoria and even against naturally occurring bacterial spot disease. We identified an additiveeffect on induced resistance after administration of a combination treatment composed of strain INR7 with a chemical inducer, benzothiadiazole (BTH in the field. The combination treatment stimulated expression of pepper defence marker genes CaPR1, CaTin1, and CaPR4 to a greater extent than did treatment with either agent alone. Similar experiments conducted with tobacco revealed no additive effects under field conditions. Interestingly, co-application of plants with INR7 lifted the growth repressing effect of BTH. Application of benzothiadiazole onto pepper and tobacco did not affect rhizosphere colonisation but supported a higher population density inside plant roots when compared to water-treated control plants. Our results

  10. A Low Power RC-Coupled VHF Amplifier Designed for Fabrication by Hybrid Microcircuit Techniques.

    Science.gov (United States)

    RADIOFREQUENCY AMPLIFIERS, HYBRID CIRCUITS, MICROMINIATURIZATION , VERY HIGH FREQUENCY, MODULES(ELECTRONICS), TRANSISTOR AMPLIFIERS, RADIO RECEIVERS, COMMUNICATION EQUIPMENT, SATELLITE COMMUNICATIONS.

  11. Tuneable, non-degenerated, nonlinear, parametrically-excited amplifier

    Science.gov (United States)

    Dolev, Amit; Bucher, Izhak

    2016-01-01

    The proposed parametric amplifier scheme can be tuned to amplify a wide range of input frequencies by altering the parametric excitation with no need to physically modify the oscillator. Parametric amplifiers had been studied extensively, although most of the work focused on amplifiers that are parametrically excited at a frequency twice the amplifier's natural frequency. These amplifiers are confined to amplifying predetermined frequencies. The proposed parametric amplifier's bandwidth is indeed tuneable to nearly any input frequency, not bound to be an integer multiple of a natural frequency. In order to tune the stiffness and induce a variable frequency parametric excitation, a digitally controlled electromechanical element must be incorporated in the realization. We introduce a novel parametric amplifier with nonlinearity, Duffing type hardening, that bounds the otherwise unlimited amplitude. Moreover, we present a multi degree of freedom system in which a utilization of the proposed method enables the projection of low frequency vector forces on any eigenvector and corresponding natural frequency of the system, and thus to transform external excitations to a frequency band where signal levels are considerably higher. Using the method of multiple scales, analytical expressions for the responses have been retrieved and verified numerically. Parametric studies of the amplifiers' gain, sensitivities and spatial projection of the excitation on the system eigenvectors were carried out analytically. The results demonstrate the advantage of the proposed approach over existing schemes. Practical applications envisaged for the proposed method will be outlined.

  12. Effect of cold-induced changes in physical and chemical leaf properties on the resistance of winter triticale (xTriticosecale) to the fungal pathogen Microdochium nivale

    NARCIS (Netherlands)

    Szechynska-Hebda, M.; Hebda, M.; Mierzwinski, D.; Kuczynska, P.; Mirek, M.; Wedzony, M.; Lammeren, van A.; Karpinski, S.

    2013-01-01

    This study showed that several mechanisms of the basal resistance of winter triticale to Microdochium nivale are cultivar-dependent and can be induced specifically during plant hardening. Experiments and microscopic observations were conducted on triticale cvs Hewo (able to develop resistance after

  13. The influence of amplifier, interface and biological noise on signal quality in high-resolution EEG recordings.

    Science.gov (United States)

    Scheer, Hans J; Sander, Tilmann; Trahms, Lutz

    2006-02-01

    First, the intrinsic random noise sources of a biopotential measurement in general are reviewed. For the special case of an electroencephalographic (EEG) measurement we have extended the commonly used amplifier noise model by biological generated background noise. As the strongest of all noise sources involved will dominate the resulting signal to noise ratio (S/N), we have investigated under which conditions this will be the case. We illustrate experimentally that up to 100 Hz S/N practically depends only on cortical generated background noise, while at a few hundred Hz or more amplifier and thermal noise of interelectrode resistance are the major sources.

  14. Layered-nanomaterial-amplified chemiluminescence systems and their analytical applications.

    Science.gov (United States)

    Zhong, Jinpan; Yuan, Zhiqin; Lu, Chao

    2016-12-01

    Layered nanomaterial has become a popular hierarchical material for amplifying chemiluminescence (CL) in recent years, mainly because of its ease of preparation and modification, large specific surface area, and high catalytic activity. In this review, we mainly discuss layered-nanomaterial-amplified CL systems based on graphene and its derivatives, layered double hydroxides, and clay. Detection mechanisms and strategies of layered-nanomaterial-amplified CL systems are provided to show the basic concepts for designing sensitive and selective sensing systems. Strategies for expanding the applications of layered-nanomaterial-amplified CL systems by combination with surfactants, quantum dots, organic dyes, and nanoparticles are introduced for the analysis of various analytes in real samples. The challenges and future trends of layered-nanomaterial-amplified CL systems are discussed at the end of the review. Graphical Abstract Schematic illustration of layered nanomaterial amplified chemiluminescence.

  15. Method and apparatus for linear low-frequency feedback in monolithic low-noise charge amplifiers

    Science.gov (United States)

    DeGeronimo, Gianluigi

    2006-02-14

    A charge amplifier includes an amplifier, feedback circuit, and cancellation circuit. The feedback circuit includes a capacitor, inverter, and current mirror. The capacitor is coupled across the signal amplifier, the inverter is coupled to the output of the signal amplifier, and the current mirror is coupled to the input of the signal amplifier. The cancellation circuit is coupled to the output of the signal amplifier. A method of charge amplification includes providing a signal amplifier; coupling a first capacitor across the signal amplifier; coupling an inverter to the output of the signal amplifier; coupling a current mirror to the input of the signal amplifier; and coupling a cancellation circuit to the output of the signal amplifier. A front-end system for use with radiation sensors includes a charge amplifier and a current amplifier, shaping amplifier, baseline stabilizer, discriminator, peak detector, timing detector, and logic circuit coupled to the charge amplifier.

  16. GaN-based Power amplifiers for microwave applications

    Directory of Open Access Journals (Sweden)

    Jorge Julián Moreno-Rubio

    2016-01-01

    Full Text Available This paper presents a discussion about the design strategies of different kind of power amplifiers for RF/Microwave appli- cations, such as the tuned load power amplifier, class F, class F-1 and Doherty. Furthermore, it is shown the continuous wave characterization of the amplifiers above mentioned. A comparison between the obtained results, in terms of gain, efficiency and output power is presented.

  17. InP Heterojunction Bipolar Transistor Amplifiers to 255 GHz

    Science.gov (United States)

    Radisic, Vesna; Sawdai, Donald; Scott, Dennis; Deal, William; Dang, Linh; Li, Danny; Cavus, Abdullah; To, Richard; Lai, Richard

    2009-01-01

    Two single-stage InP heterojunction bipolar transistor (HBT) amplifiers operate at 184 and 255 GHz, using Northrop Grumman Corporation s InP HBT MMIC (monolithic microwave integrated circuit) technology. At the time of this reporting, these are reported to be the highest HBT amplifiers ever created. The purpose of the amplifier design is to evaluate the technology capability for high-frequency designs and verify the model for future development work.

  18. Modeling and design techniques for RF power amplifiers

    CERN Document Server

    Raghavan, Arvind; Laskar, Joy

    2008-01-01

    The book covers RF power amplifier design, from device and modeling considerations to advanced circuit design architectures and techniques. It focuses on recent developments and advanced topics in this area, including numerous practical designs to back the theoretical considerations. It presents the challenges in designing power amplifiers in silicon and helps the reader improve the efficiency of linear power amplifiers, and design more accurate compact device models, with faster extraction routines, to create cost effective and reliable circuits.

  19. Isolation Amplifier Based On Sigma-Delta Modulation

    Science.gov (United States)

    Harres, Daniel N.

    1994-01-01

    Improved isolation amplifier transmits dc or low-frequency analog signal by use of digital pulses. Relatively imprecise digital pulses convey analog signal with relatively high precision. Amplifier implements sigma-delta modulation scheme. Circuit used wherever conventional amplifier needed. Includes medical instrumentation, switching-type power supplies, and other applications in which input voltages must be measured in presence of large common-mode voltages.

  20. A high performance switching audio amplifier using sliding mode control

    OpenAIRE

    Pillonnet, Gael; Cellier, Rémy; Abouchi, Nacer; Chiollaz, Monique

    2008-01-01

    International audience; The switching audio amplifiers are widely used in various portable and consumer electronics due to their high efficiency, but suffers from low audio performances due to inherent nonlinearity. This paper presents an integrated class D audio amplifier with low consumption and high audio performances. It includes a power stage and an efficient control based on sliding mode technique. This monolithic class D amplifier is capable of delivering up to 1W into 8Ω load at less ...

  1. Multimode Traveling-Wave Amplifier Tubes

    Science.gov (United States)

    Buck, E.

    1981-02-01

    The paper examines the recent developments which makes the Traveling Wave Tube (TWT) more powerful and efficient as a microwave amplifier than the solid state devices. Basic workings and efficiency, which can run, but usually do not, to 55%, are examined. The dependence of the performance of a given TWT upon the qualities of the beam and the manner of its focusing is described. Also described is the development of a multistage depressed collector (MDC) and its first application to a Communication Technology Satellite (CTS) tube, a 12 GHz, coupled-cavity, 200 watt TWT, which resulted in being operated in space for nearly four years and was both the most powerful and the most efficient (around 50%) communications TWT ever flown. It is predicted that the application of efficient refocusing and MDCs, made possible by computer simulations, will greatly increase tube efficiency, and thereby make practical, new multimode tubes which operate, as least partly, in a linear fashion.

  2. Stochastic phenomena in a fiber Raman amplifier

    CERN Document Server

    Kalashnikov, Vladimir; Ania-Castanón, Juan Diego; Jacobsen, Gunnar; Popov, Sergei

    2016-01-01

    The interplay of such cornerstones of modern nonlinear fiber optics as a nonlinearity, stochasticity and polarization leads to variety of the noise induced instabilities including polarization attraction and escape phenomena harnessing of which is a key to unlocking the fiber optic systems specifications required in high resolution spectroscopy, metrology, biomedicine and telecommunications. Here, by using direct stochastic modeling, the mapping of interplay of the Raman scattering-based nonlinearity, the random birefringence of a fiber, and the pump-to-signal intensity noise transfer has been done in terms of the fiber Raman amplifier parameters, namely polarization mode dispersion, the relative intensity noise of the pump laser, fiber length, and the signal power. The obtained results reveal conditions for emergence of the random birefringence-induced resonance-like enhancement of the gain fluctuations (stochastic anti-resonance) accompanied by pulse broadening and rare events in the form of low power outpu...

  3. Self-amplified optical pattern recognition system

    Science.gov (United States)

    Liu, Hua-Kuang (Inventor)

    1994-01-01

    A self amplifying optical pattern recognizer includes a geometric system configuration similar to that of a Vander Lugt holographic matched filter configuration with a photorefractive crystal specifically oriented with respect to the input beams. An extraordinarily polarized, spherically converging object image beam is formed by laser illumination of an input object image and applied through a photorefractive crystal, such as a barium titanite (BaTiO.sub.3) crystal. A volume or thin-film dif ORIGIN OF THE INVENTION The invention described herein was made in the performance of work under a NASA contract, and is subject to the provisions of Public Law 96-517 (35 USC 202) in which the Contractor has elected to retain title.

  4. A Superconducting Linac for the Energy Amplifier

    Science.gov (United States)

    Ruggiero, A. G.

    1997-05-01

    Because of the safer and more reliable mode of operation, a Superconducting Linac is proposed here as the proton beam accelerator which drives a nuclear plant based on the concept of the Energy Amplifier. The accelerator has also high electric power efficiency, estimated around 40%. An example based on the net generation of 400 MW (electric) is described here. This requires a proton beam energy of 1 GeV with a continuous beam current of 10 mA, corresponding to a beam power of 10 MW. The study compares the cost and performance of several rf cavity frequencies, namely 350 versus 800 MHz. Higher power values can be obtained with larger beam energy and intensity. A re-circulation configuration mode of the Linac is also proposed and studied.

  5. Rippled beam free electron Laser Amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Carlsten, Bruce E.

    1998-04-21

    A free electron laser amplifier provides a scalloping annular electron beam that interacts with the axial electric field of a T{sub 0n} mode. A waveguide defines an axial centerline and . A solenoid arranged about the waveguide produces an axial constant magnetic field within the waveguide. An electron beam source outputs a annular electron beam that interacts with the axial magnetic field to have an equilibrium radius and a ripple radius component having a variable radius with a ripple period along the axial centerline. An rf source outputs an axial electric field that propagates within the waveguide coaxial with the electron beam and has a radial mode that interacts at the electron beam at the equilibrium radius component of the electron beam.

  6. Low-noise two-wired buffer electrodes for bioelectric amplifiers.

    Science.gov (United States)

    Degen, Thomas; Torrent, Simon; Jäckel, Heinz

    2007-07-01

    Active buffer electrodes are known to improve the immunity of bioelectric recordings against power line interferences. A survey of published work reveals that buffer electrodes are almost exclusively designed using operational amplifiers (opamps). In this paper, we discuss the advantage of utilizing a single transistor instead. This allows for a simple electrode, which is small and requires only two wires. In addition, a single transistor adds considerably less noise when compared to an opamp with the same power consumption. We then discuss output resistance and gain as well as their respective effect on the common mode rejection ratio (CMRR). Finally, we demonstrate the use of two-wired buffer electrodes for a bioelectric amplifier.

  7. The eight-channel ASIC bipolar transresistance amplifier D0M AMPL-8.3

    CERN Document Server

    Alexeev, G D; Dvornikov, O V; Khokhlov, A I; Mikhailov, V A; Odnokloubov, I A; Tokmenin, V V

    2001-01-01

    The eight-channel ASIC low-noise bipolar transresistance amplifier D0M Ampl-8.3 has been designed on the basis of BJT-JFET technology for gaseous wire detectors used in high-energy physics experiments. The amplifier has differential gain 130 mV/mu A at 1 k OMEGA, input noise 35 and 60 nA r.m.s. at 0 and 60 pF input capacitance, respectively, leading/trailing edge 7 ns, input resistance approx 50 OMEGA, crosstalks -47 dB, dissipated power 160 triple bond 640 mW/chip for +-3 triple bond 5 V supply. The Ampl-8.3 has been accepted for upgrading the Forward Angle Muon System of the D0 experiment (Fermilab, Batavia, USA), the total number of channels is about 50,000.

  8. Efficiency of Switch-Mode Power Audio Amplifiers - Test Signals and Measurement Techniques

    DEFF Research Database (Denmark)

    Iversen, Niels Elkjær; Knott, Arnold; Andersen, Michael A. E.

    2016-01-01

    Switch-mode technology is greatly used for audio amplification. This is mainly due to the great efficiency this technology offers. Normally the efficiency of a switch-mode audio amplifier is measured using a sine wave input. However this paper shows that sine waves represent real audio very poorly....... An alternative signal is proposed for test purposes. The efficiency of a switch-mode power audio amplifier is modelled and measured with both sine wave and the proposed test signal as inputs. The results show that the choice of switching devices with low on resistances are unfairly favored when measuring...... the efficiency with sine waves. A 10% efficiency improvement was found for low power outputs. It is therefore of great importance to use proper test signals when measuring the efficiency....

  9. Parametric Amplifiers for Microwave Kinectic Inductance Detector (MKID) Readout Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Find numerical solutions to the non-linear partial differential equations describing our amplifier transmission lines. Optimize periodic choke structure to block...

  10. Saturation and noise properties of quantum-dot optical amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper

    2004-01-01

    Based on extensive numerical calculations, quantum-dot (QD) amplifiers are predicted to offer higher output power and lower noise figure compared to bulk as well as quantum well amplifiers. The underlying physical mechanisms are analyzed in detail, leading to the identification of a few key...... requirements that QD amplifiers should meet in order to achieve such superior linear characteristics. The existence of a highly inverted wetting layer or barrier region, acting as a carrier reservoir, is central to this performance enhancement. It is shown that amplified spontaneous emission acts to decrease...

  11. Dual Band High Efficiency Power Amplifier Based on CRLH Lines

    Directory of Open Access Journals (Sweden)

    D. Segovia-Vargas

    2009-12-01

    Full Text Available In this paper we propose the use of Composite Right/Left Hand (CRLH and Extended Composite Right/Left Hand (ECRLH transmission lines for the design of dual band high efficiency power amplifiers working in CE class. The harmonic termination can be synthesized using the meta-lines is particularly suitable for CE class amplifiers, which have a termination not as sensitive to the third harmonic as F class amplifier. This paper presents the design procedure and the design equations. The nonlinear phase response of a CRLH and ECRLH transmission line has been utilized to design arbitrary dual-band amplifiers.

  12. Digitally gain controlled linear high voltage amplifier for laboratory applications

    Science.gov (United States)

    Koçum, C.

    2011-08-01

    The design of a digitally gain controlled high-voltage non-inverting bipolar linear amplifier is presented. This cost efficient and relatively simple circuit has stable operation range from dc to 90 kHz under the load of 10 kΩ and 39 pF. The amplifier can swing up to 360 Vpp under these conditions and it has 2.5 μs rise time. The gain can be changed by the aid of JFETs. The amplifiers have been realized using a combination of operational amplifiers and high-voltage discrete bipolar junction transistors. The circuit details and performance characteristics are discussed.

  13. Time-Domain UWB RFID Tag Based on Reflection Amplifier

    OpenAIRE

    Girbau, D.; Villarino, R.; Ramos, A.; Lazaro, A.

    2013-01-01

    10.1109/LAWP.2013.2257653 This letter describes an active ultrawideband (UWB) tag for radio frequency identification (RFID) and wireless sensor applications. The tag is composed by a UWB antenna connected to a one-port reflection amplifier. A UWB impulse radar is used as the reader. The reader sends a short pulse, and its echo is amplified and reflected back due to the return gain of the tag amplifier. The amplitude of the reflected pulse is modulated by controlling the amplifier bias. Th...

  14. Switching-mode Audio Power Amplifiers with Direct Energy Conversion

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper presents a new class of switching-mode audio power amplifiers, which are capable of direct energy conversion from the AC mains to the audio output. They represent an ultimate integration of a switching-mode power supply and a Class D audio power amplifier, where the intermediate DC bus...... has been replaced with a high frequency AC link. When compared to the conventional Class D amplifiers with a separate DC power supply, the proposed single conversion stage amplifier provides simple and compact solution with better efficiency and higher level of integration, leading to reduced...

  15. Nylon Sleeve for Cavity Amplifier Holds Tuning Despite Heat

    Science.gov (United States)

    Derr, Lloyd

    1964-01-01

    The problem: Detuning of cavity amplifiers with change in temperature. This results in deterioration of the performance of the amplifier at its design frequency. In cavity amplifiers and filters it is desirable that constant performance be maintained regardless of thermal changes. These changes often cause an "off resonance shift" in a cavity filter and a deterioration of performance in a cavity amplifier. The solution: Mount the tuning probe in a nylon sleeve. Thermal expansion and contraction of the nylon nullifies unwanted capacitive and inductive changes in the resonant elements.

  16. An instrumentation amplifier based readout circuit for a dual element microbolometer infrared detector

    Science.gov (United States)

    de Waal, D. J.; Schoeman, J.

    2014-06-01

    The infrared band is widely used in many applications to solve problems stretching over very diverse fields, ranging from medical applications like inflammation detection to military, security and safety applications employing thermal imaging in low light conditions. At the heart of these optoelectrical systems lies a sensor used to detect incident infrared radiation, and in the case of this work our focus is on uncooled microbolometers as thermal detectors. Microbolometer based thermal detectors are limited in sensitivity by various parameters, including the detector layout and design, operating temperature, air pressure and biasing that causes self heating. Traditional microbolometers use the entire membrane surface for a single detector material. This work presents the design of a readout circuit amplifier where a dual detector element microbolometer is used, rather than the traditional single element. The concept to be investigated is based on the principle that both elements will be stimulated with a similar incoming IR signal and experience the same resistive change, thus creating a common mode signal. However, such a common mode signal will be rejected by a differential amplifier, thus one element is placed within a negative resistance converter to create a differential mode signal that is twice the magnitude of the comparable single mode signal of traditional detector designs. An instrumentation amplifier is used for the final stage of the readout amplifier circuit, as it allows for very high common mode rejection with proper trimming of the Wheatstone bridge to compensate for manufacturing tolerance. It was found that by implementing the above, improved sensitivity can be achieved.

  17. Fungicide resistance of Botrytis cinerea in tomato greenhouses in the Canary Islands and effectiveness of non-chemical treatments against gray mold.

    Science.gov (United States)

    Rodríguez, A; Acosta, A; Rodríguez, C

    2014-09-01

    Tomato greenhouses in the Canary Islands, Spain, were surveyed to estimate frequencies of resistance to benzimidazoles, dicarboximides, anilinopyrimidines and N-phenylcarbamates in Botrytis cinerea. Resistance to carbendazim, iprodione, pyrimethanil and diethofencarb was found in 74.2, 86.4, 28.8 and 31.8% of isolates, respectively. Benzimidazole- and anilinopyrimide-resistant isolates were highly resistant, showing EC50 values above 500 µg/ml carbendazim and a mean EC50 value of 28.42 µg/ml pyrimethanil, respectively. By contrast, a low level of resistance was observed among dicarboximide-resistant isolates (mean EC50 value of 1.81 µg/ml iprodione). Phenotypes with double resistance to carbendazim and iprodione, and triple resistance to carbendazim, iprodione and pyrimethanil were the most common, occurring in 36.4 and 28.8% of isolates. The surveyed greenhouses had never been treated with fenhexamid and Signum™ (pre-packed mixture of boscalid and pyraclostrobin), and baseline sensitivities of B. cinerea isolates to these fungicides were determined. The EC50 values were within the range of 0.009-0.795 µg/ml fenhexamid and of 0.014-0.48 µg/ml Signum. In addition, available formulations based on elicitors of plant defense response and biocontrol agents were evaluated against B. cinerea in tomato plants under semi-controlled greenhouse conditions, the yeast Candida sake CPA-1 being able to reduce gray mold significantly when it was applied on petiole wounds and the plants were inoculated 24 h later. Likewise, C. sake was effective against B. cinerea in harvested tomato fruits, yeast-treated tomatoes showed a 70.66 and 30.31% reduction in the diameters of decay lesions compared with controls after 10 days of storage at 20 and 9 °C, respectively.

  18. Tissue Distribution, Gender-Divergent Expression, Ontogeny, and Chemical Induction of Multidrug Resistance Transporter Genes (Mdr1a, Mdr1b, Mdr2) in Mice

    OpenAIRE

    Cui, Yue Julia; Cheng, Xingguo; Weaver, Yi Miao; Klaassen, Curtis D.

    2008-01-01

    Multidrug resistance (Mdr) transporters are ATP-binding cassette transporters that efflux amphipathic cations from cells and protect tissues from xenobiotics. Unfortunately, Mdr transporters also efflux anticancer drugs from some tumor cells, resulting in multidrug resistance. There are two groups of Mdrs in mice: group I includes Mdr1a and Mdr1b that transport xenobiotics, whereas group II is Mdr2, a flipase that facilitates phospholipid excretion into bile. Little is...

  19. Visible-infrared self-amplified spontaneous emission amplifier free electron laser undulator

    Directory of Open Access Journals (Sweden)

    Roger Carr

    2001-12-01

    Full Text Available The visible-infrared self-amplified spontaneous emission amplifier (VISA free electron laser (FEL is an experimental device designed to show self-amplified spontaneous emission (SASE to saturation in the near infrared to visible light energy range. It generates a resonant wavelength output from 800–600 nm, so that silicon detectors may be used to characterize the optical properties of the FEL radiation. VISA is designed to show how SASE FEL theory corresponds with experiment in this wavelength range, using an electron beam with emittance close to that planned for the future Linear Coherent Light Source at SLAC. VISA comprises a 4 m pure permanent magnet undulator with four 99 cm segments, each of 55 periods, 18 mm long. The undulator has distributed focusing built into it, to reduce the average beta function of the 70–85 MeV electron beam to about 30 cm. There are four FODO cells per segment. The permanent magnet focusing lattice consists of blocks mounted on either side of the electron beam, in the undulator gap. The most important undulator error parameter for a free electron laser is the trajectory walk-off, or lack of overlap of the photon and electron beams. Using pulsed wire magnet measurements and magnet shimming, we were able to control trajectory walk-off to less than ±50 μm per field gain length.

  20. Identification of different selected genotypes of salinity resistance of ...

    African Journals Online (AJOL)

    sib Nile tilapia, Blue tilapia and their diallel interspecific hybridization using random amplified ... African Journal of Biotechnology ... Keywords: RAPD fingerprinting, salinity resistance, Nile tilapia, Blue tilapia, interspecific hybridization ...

  1. Slow Light at High Frequencies in an Amplifying Semiconductor Waveguide

    DEFF Research Database (Denmark)

    Öhman, Filip; Yvind, Kresten; Mørk, Jesper

    2006-01-01

    We demonstrate slow-down of a modulated light signal in a semiconductor waveguide. Concatenated amplifying and absorbing sections simultaneously achieve both amplification and a controllable time delay at 15 GHz.......We demonstrate slow-down of a modulated light signal in a semiconductor waveguide. Concatenated amplifying and absorbing sections simultaneously achieve both amplification and a controllable time delay at 15 GHz....

  2. Phase Sensitive Amplifier Based on Ultrashort Pump Pulses

    CERN Document Server

    Gershikov, Alexander

    2016-01-01

    We demonstrate a narrow band phase sensitive amplifier in the pump degenerate configuration which employs ps pump pulses. Control of the amplifier bandwidth is achieved via changes of the pump spectral width. A phase sensitive gain between -6 and 6 decibels, with an overall system gain of 28dB was demonstrated.

  3. Energy Efficient and Compact RF High-Power Amplifiers

    NARCIS (Netherlands)

    Calvillo Cortés, D.A.

    2014-01-01

    The main objectives of this thesis are to improve the energy efficiency and physical form-factor of high-power amplifiers in base station applications. As such, the focus of this dissertation is placed on the outphasing amplifier concept, which can offer high-efficiency, good linearity and excellent

  4. Gain characteristics of a saturated fiber optic parametric amplifier

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Lorenzen, Michael Rodas; Noordegraaf, Danny

    2008-01-01

    In this work we discuss saturation performance of a fiber optic parametric amplifier. A simple numerical model is described and applied to specific cases. A system experiment using a saturated amplifier illustrates a 4 dB improvement in required signal to noise ratio for a fixed bit error ratio....

  5. The design of erbium-doped fiber amplifiers

    DEFF Research Database (Denmark)

    Pedersen, Bo; Bjarklev, Anders Overgaard; Povlsen, Jørn Hedegaard

    1991-01-01

    An accurate model for the erbium-doped fiber amplifier is presented. The model is used to design the index profile of the doped fiber, optimizing with regard to efficiency for inline- and preamplifiers as well as for power booster amplifiers. The predicted pump efficiencies (maximum gain to pump...

  6. Series-Tuned High Efficiency RF-Power Amplifiers

    DEFF Research Database (Denmark)

    Vidkjær, Jens

    2008-01-01

    An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits.......An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits....

  7. Ultrafast Dynamics of Quantum-Dot Semiconductor Optical Amplifiers

    DEFF Research Database (Denmark)

    Poel, Mike van der; Hvam, Jørn Märcher

    2007-01-01

    We report on a series of experiments on the dynamical properties of quantum-dot semiconductor optical amplifiers. We show how the amplifier responds to one or several ultrafast (170 fs) pulses in rapid succession and our results demonstrate applicability and ultimate limitations to application...

  8. The Warm, Rich Sound of Valve Guitar Amplifiers

    Science.gov (United States)

    Keeports, David

    2017-01-01

    Practical solid state diodes and transistors have made glass valve technology nearly obsolete. Nevertheless, valves survive largely because electric guitar players much prefer the sound of valve amplifiers to the sound of transistor amplifiers. This paper discusses the introductory-level physics behind that preference. Overdriving an amplifier…

  9. PHEMT Distributed Power Amplifier Adopting Broadband Impedance Transformer

    DEFF Research Database (Denmark)

    Narendra, K.; Limiti, E.; Paoloni, C.

    2013-01-01

    A non-uniform drain line distributed power amplifier (DPA) employing a broadband impedance transformer is presented. The DPA is based on GaAs PHEMT technology. The impedance transformer employs asymmetric coupled lines and transforms a low output impedance of the amplifier to a standard 50 Ω...

  10. Fast processes in semiconductor optical amplifiers: theory and experiment

    DEFF Research Database (Denmark)

    Mørk, Jesper

    2002-01-01

    We review the physical processes responsible for ultrafast gain and index dynamics in semiconductor optical amplifiers and discuss their impact on optical switching applications......We review the physical processes responsible for ultrafast gain and index dynamics in semiconductor optical amplifiers and discuss their impact on optical switching applications...

  11. Externally pumped millimeter-wave Josephson-junction parametric amplifier

    DEFF Research Database (Denmark)

    Levinsen, M.T; Pedersen, Niels Falsig; Sørensen, Ole

    1980-01-01

    A unified theory of the singly and doubly degenerate Josephson-junction parametric amplifier is presented. Experiments with single junctions on both amplifier modes at frequencies 10, 35, and 70 GHz are discussed. Low-noise temperature (∼100 K, single sideband (SSB)) and reasonable gain (∼8 d...

  12. A Review of High Voltage Drive Amplifiers for Capacitive Actuators

    DEFF Research Database (Denmark)

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.

    2012-01-01

    This paper gives an overview of the high voltage amplifiers, which are used to drive capacitive actuators. The amplifiers for both piezoelectric and DEAP (dielectric electroactive polymer) actuator are discussed. The suitable topologies for driving capacitive actuators are illustrated in detail...

  13. A Power Efficient Audio Amplifier Combining Switching and Linear Techniques

    NARCIS (Netherlands)

    van der Zee, Ronan A.R.; van Tuijl, Adrianus Johannes Maria

    1998-01-01

    Integrated Class D audio amplifiers are very power efficient, but require an external filter which prevents further integration. Also due to this filter, large feedback factors are hard to realise, so that the load influences the distortion- and transfer characteristics. The amplifier presented in

  14. Subjective test of class D amplifiers without output filter

    DEFF Research Database (Denmark)

    Agerkvist, Finn T.; Fenger, Lars M.

    2004-01-01

    This paper presents the results of subjective listening tests designed to determine whether the output filter on class D amplifiers used in active loudspeakers can be omitted without audible errors occurring. The frequency range of the amplifiers was limited to 0-3 kHz corresponding to a woofer...

  15. 21 CFR 870.2050 - Biopotential amplifier and signal conditioner.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Biopotential amplifier and signal conditioner. 870.2050 Section 870.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... conditioner is a device used to amplify or condition an electrical signal of biologic origin. (b...

  16. Ferroelectric Field-Effect Transistor Differential Amplifier Circuit Analysis

    Science.gov (United States)

    Phillips, Thomas A.; MacLeod, Todd C.; Ho, Fat D.

    2008-01-01

    There has been considerable research investigating the Ferroelectric Field-Effect Transistor (FeFET) in memory circuits. However, very little research has been performed in applying the FeFET to analog circuits. This paper investigates the use of FeFETs in a common analog circuit, the differential amplifier. The two input Metal-Oxide-Semiconductor (MOS) transistors in a general MOS differential amplifier circuit are replaced with FeFETs. Resistors are used in place of the other three MOS transistors. The FeFET model used in the analysis has been previously reported and was based on experimental device data. Because of the FeFET hysteresis, the FeFET differential amplifier has four different operating modes depending on whether the FeFETs are positively or negatively polarized. The FeFET differential amplifier operation in the different modes was analyzed by calculating the amplifier voltage transfer and gain characteristics shown in figures 2 through 5. Comparisons were made between the FeFET differential amplifier and the standard MOS differential amplifier. Possible applications and benefits of the FeFET differential amplifier are discussed.

  17. RAMAN amplifier gain dynamics with ASE : Numerical analysis and ...

    African Journals Online (AJOL)

    Spontaneous Raman scattering add up with the amplified signal and reflect as a noise because of random phases linked with all spontaneously generated photons. The amplified spontaneous emission noise in systems with distributed Raman gain for single pump amplification is diagnosed numerically and simulated using ...

  18. External Peltier Cooler For Low-Noise Amplifier

    Science.gov (United States)

    Soper, Terry A.

    1990-01-01

    Inexpensive Peltier-effect cooling module made of few commercially available parts used to reduce thermal noise in microwave amplifier. Retrofitted to almost any microwave low-noise amplifier or receiver preamplifier used in communication, telemetry, or radar. Includes copper or aluminum cold plate held tightly against unit to be cooled by strap-type worm-gear clamps.

  19. Cross-talk free, low-noise optical amplifier

    Science.gov (United States)

    Dijaili, Sol P.; Patterson, Frank G.; Deri, Robert J.

    1995-01-01

    A low-noise optical amplifier solves crosstalk problems in optical amplifiers by using an optical cavity oriented off-axis (e.g. perpendicular) to the direction of a signal amplified by the gain medium of the optical amplifier. Several devices are used to suppress parasitic lasing of these types of structures. The parasitic lasing causes the gain of these structures to be practically unusable. The lasing cavity is operated above threshold and the gain of the laser is clamped to overcome the losses of the cavity. Any increase in pumping causes the lasing power to increase. The clamping action of the gain greatly reduces crosstalk due to gain saturation for the amplified signal beam. It also reduces other nonlinearities associated with the gain medium such as four-wave mixing induced crosstalk. This clamping action can occur for a bandwidth defined by the speed of the laser cavity. The lasing field also reduces the response time of the gain medium. By having the lasing field off-axis, no special coatings are needed. Other advantages are that the lasing field is easily separated from the amplified signal and the carrier grating fluctuations induced by four-wave mixing are decreased. Two related methods reduce the amplified spontaneous emission power without sacrificing the gain of the optical amplifier.

  20. Amplifying Islam : Pluralism, Secularism, and Religious Sounds in The Netherlands

    NARCIS (Netherlands)

    Tamimi Arab, P.

    2015-01-01

    This dissertation is an ethnographic study of the amplified azan, the Islamic call to prayer, in the Netherlands, adding a sonic dimension to analyses of the politics of Islamic aesthetics in the western world. Often rejected by opponents as noise pollution, facilitating the amplified azan is an

  1. Comparative Study of Two Multilevel Converters for Envelope Amplifier

    Directory of Open Access Journals (Sweden)

    Miroslav Vasić

    2010-06-01

    Full Text Available Modern transmitters usually have to amplify and transmit signals with simultaneous envelope and phase modulation. Due to this property of the transmitted signal, linear power amplifiers (class A, B or AB are usually used as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has low peak-to-average power ratio. The Kahn envelope elimination and restoration (EER technique is used to enhance efficiency of RF transmitters, by combining highly efficient,nonlinear RF amplifier (class D or E with a highly efficient envelope amplifier in order to obtain linear and highly efficientRF amplifier. This paper compares two solutions for the envelope amplifier based on a combination of multilevel converter and linear regulator. The solutions are compared regarding their efficiency, size and weight. Both solutions can reproduce any signal with maximal spectral component of 2 MHz and give instantaneous maximal power of 50 W. The efficiency measurements show that when the signals with low average value are transmitted, the implemented prototypes have up to 20% higher efficiency than linear regulator that is used as a conventional solution.

  2. A novel method to design variable gain amplifier | Mahdavi | Journal ...

    African Journals Online (AJOL)

    A novel method to design variable gain amplifier. S Mahdavi, A Soltani, M Jafarzadeh, T Moradi Khanshan. Abstract. A novel method to design of Variable gain Amplifiers (VGAs) is proposed. A low power VGA with wide range of gain variation and appropriate bandwidth using new technique is presented in this paper.

  3. Multi Carrier Modulation Audio Power Amplifier with Programmable Logic

    DEFF Research Database (Denmark)

    Christiansen, Theis; Andersen, Toke Meyer; Knott, Arnold

    2009-01-01

    . Analytically expressions, simulations and measurements result in reduced switching frequency amplitudes using MCM techniques. It is also shown that the Total Harmonic Distortion (THD) tends to be compromised compared to conventional class D amplifiers due to intermodulation products of the switching......While switch-mode audio power amplifiers allow compact implementations and high output power levels due to their high power efficiency, they are very well known for creating electromagnetic interference (EMI) with other electronic equipment. To lower the EMI of switch-mode (class D) audio power...... amplifiers while keeping the performance measures to excellent levels is therefore of high interest. In this paper a class D audio amplifier utilising Multi Carrier Modulation (MCM) will be analysed, and a prototype Master-Slave Multi Carrier Modulated (MS MCM) amplifier has been constructed and measured...

  4. Pulse-width-modulated amplifier drives for machine tools

    Energy Technology Data Exchange (ETDEWEB)

    Barkman, W.E.

    1979-11-01

    The function of a dc servo controller is to convert command and feedback information into an error signal that is used to drive a dc motor. To accomplish this, the controller utilizes a summing technique that compares an input-command voltage with a feedback voltage from an external transducer. The resultant error signal is applied to a linear or a switching servo amplifier. While the output of the linear amplifier may have the ideal representation of the desired drive signal, it does result in substantial power dissipation within the amplifier and requires forced-air cooling for power ratings above 100 to 200 W. The switching amplifier avoids this problem by rapidly changing the state of its output stage from a conducting to a nonconducting condition, thereby minimizing the operation of the output stage in the high power-dissipation region. The design and operation of the amplifier drive are described. (TFD)

  5. Capacitive Trans-Impedance Amplifier Circuit with Charge Injection Compensation

    Science.gov (United States)

    Milkov, Mihail M. (Inventor); Gulbransen, David J. (Inventor)

    2016-01-01

    A capacitive trans-impedance amplifier circuit with charge injection compensation is provided. A feedback capacitor is connected between an inverting input port and an output port of an amplifier. A MOS reset switch has source and drain terminals connected between the inverting input and output ports of the amplifier, and a gate terminal controlled by a reset signal. The reset switch is open or inactive during an integration phase, and closed or active to electrically connect the inverting input port and output port of the amplifier during a reset phase. One or more compensation capacitors are provided that are not implemented as gate oxide or MOS capacitors. Each compensation capacitor has a first port connected to a compensation signal that is a static signal or a toggling compensation signal that toggles between two compensation voltage values, and a second port connected to the inverting input port of the amplifier.

  6. Evidence, Mechanism and Alternative Chemical Seedbank-Level Control of Glyphosate Resistance of a Rigid Ryegrass (Lolium rigidum) Biotype from Southern Spain.

    Science.gov (United States)

    Fernández-Moreno, Pablo T; Bastida, Fernando; De Prado, Rafael

    2017-01-01

    Rigid ryegrass (Lolium rigidum) is one of the most troublesome weeds in different crops in the Mediterranean region. A rigid ryegrass biotype from an olive grove in Jaén province (Andalusía, southern Spain), potentially resistant to glyphosate (RG), was tested for its resistance level through dose-response assays using a susceptible biotype (SG). To test the hypothesis of a non-target-site-based resistance, as point mutations are far less common mechanisms of glyphosate resistance, studies were also conducted to elucidate whether resistance was associated with biochemical, metabolism, molecular and/or physiological mechanisms. Alternative herbicide-based control options, including single-herbicide or herbicide mixtures with glyphosate, applied at seedling, tillering or full heading stages, were tested in field experiments for 2 years for their efficacy against rigid ryegrass plants and their effects on the soil seed bank. Resistance levels of the RG biotype were 23- (LD50) and 7-fold (GR50) higher compared to the SG biotype. The SG biotype exhibited a significantly greater shikimic acid accumulation than the RG one. At 96 HAT, 58 and 89% of applied 14C-glyphosate was up taken by leaves of RG and SG biotype plants, respectively, and, at this time, a significantly higher proportion of the glyphosate taken up by the treated leaf remained in its tissue in RG plants compared to the SG ones. The RG biotype did not reveal any point mutation in the glyphosate target site EPSP synthase. Overall, results confirmed reduced glyphosate uptake and translocation as being the mechanism involved in glyphosate resistance in the RG biotype. RG biotype responses to the alternative treatments tested in situ indicated that herbicide applications at the later growth stage tended to be less effective in terms of immediate effects on population size than earlier applications, and that only in some cases, the removal of at least 85% of the RG biotype was achieved. However, with few

  7. Amplifying Riboswitch Signal Output using Cellular Wiring

    Science.gov (United States)

    2017-01-30

    replication and chloramphenicol resistance gene. The 2AP riboswitch amplification circuit was compared to the plasmid containing the 2AP riboswitch directly...241 7. Brenner, K., Karig, D. K., Weiss, R., and Arnold, F. H. (2007) Engineered bidirectional communication mediates a consensus in a microbial

  8. Methylation sensitive amplified polymorphism (MSAP) reveals that ...

    African Journals Online (AJOL)

    ajl yemi

    2011-12-19

    Dec 19, 2011 ... regulation mechanism of DNA methylation, have not been fully understood. The ability of plants to differently regulate gene expression and protein function has been described as a key factor in plant resistance (Lo´pez-. Maury et al., 2008). In this regard, epigenetic mechanisms such as DNA methylation ...

  9. Fishing amplifies forage fish population collapses.

    Science.gov (United States)

    Essington, Timothy E; Moriarty, Pamela E; Froehlich, Halley E; Hodgson, Emma E; Koehn, Laura E; Oken, Kiva L; Siple, Margaret C; Stawitz, Christine C

    2015-05-26

    Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches.

  10. Efficient and Compact Optical Amplifier Using EYDF

    Directory of Open Access Journals (Sweden)

    Sulaiman Wadi Harun

    2010-09-01

    Full Text Available An efficient Erbium/Ytterbium doped fiber amplifier (EYDFA is demonstrated using a 1058nm pumping wavelength, where the amplification is assisted by energy transfer between Yb and Er ions. The energy transfer increases the limit of erbium doping concentration that is imposed by concentration quenching in Erbium-doped fiber (EDF. Therefore, the gain and noise figure are severely degraded with 1480 nm pumping, where the energy transfer cannot be achieved. The use of optical isolator improves the small signal gain and noise figure by about 4.8 dB and 1.6 dB, respectively. By employing a double-pass configuration, a higher gain can be obtained with an expense of a noise figure penalty. The gain improvement of 17.0 dB is obtained at 20 mW and -50 dBm of pump and input signal powers. This shows that the double-pass configuration is an important aspect to consider when designing an efficient EYDFA.

  11. Status Report on the Energy Amplifier

    CERN Document Server

    Rubbia, Carlo

    1994-01-01

    0ne year after its first presentation,the Energy Amplifier (EA) Project holds its promises for a environmentally acceptable form of energy extraction from nuclei, namely to eliminate or at least greatly reduce(i) the environmental impact of the long-lived highly radioactive waste;(ii) the possibility of diversions toward military applications;(iii) the risks of an accidental divergence related to the critical operation of the chain reaction and (iv) make a more efficient use of a fuel which is less radio-toxic to extract and more abundant on Earth than Uranium. In these respects the EA (or equivalent scenarios from Los Alamos and elsewhere) is comparable in performance to Thermonuclear Fusion. Bot h approches offer pratically unl;imited fuel resources: the energetic content of Lithium on the Earth's crust needed by Fusion is estimated to be seven times the one of Thorium and they are both adequate for millions of years of very intensived utilisation.However the EA can be built economically,in a variety of siz...

  12. Gold Nanoparticle Labels Amplify Ellipsometric Signals

    Science.gov (United States)

    Venkatasubbarao, Srivatsa

    2008-01-01

    The ellipsometric method reported in the immediately preceding article was developed in conjunction with a method of using gold nanoparticles as labels on biomolecules that one seeks to detect. The purpose of the labeling is to exploit the optical properties of the gold nanoparticles in order to amplify the measurable ellipsometric effects and thereby to enable ultrasensitive detection of the labeled biomolecules without need to develop more-complex ellipsometric instrumentation. The colorimetric, polarization, light-scattering, and other optical properties of nanoparticles depend on their sizes and shapes. In the present method, these size-and-shape-dependent properties are used to magnify the polarization of scattered light and the diattenuation and retardance of signals derived from ellipsometry. The size-and-shape-dependent optical properties of the nanoparticles make it possible to interrogate the nanoparticles by use of light of various wavelengths, as appropriate, to optimally detect particles of a specific type at high sensitivity. Hence, by incorporating gold nanoparticles bound to biomolecules as primary or secondary labels, the performance of ellipsometry as a means of detecting the biomolecules can be improved. The use of gold nanoparticles as labels in ellipsometry has been found to afford sensitivity that equals or exceeds the sensitivity achieved by use of fluorescence-based methods. Potential applications for ellipsometric detection of gold nanoparticle-labeled biomolecules include monitoring molecules of interest in biological samples, in-vitro diagnostics, process monitoring, general environmental monitoring, and detection of biohazards.

  13. Stochastic phenomena in a fiber Raman amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Kalashnikov, Vladimir [Aston Institute of Photonic Technologies, Aston University, Birmingham (United Kingdom); Institute of Photonics, Vienna University of Technology (Austria); Sergeyev, Sergey V. [Aston Institute of Photonic Technologies, Aston University, Birmingham (United Kingdom); Ania-Castanon, Juan Diego [Instituto de Optica CSIC, Madrid (Spain); Jacobsen, Gunnar [Acreo, Kista (Sweden); Popov, Sergei [Royal Institute of Technology (KTH), Stockholm (Sweden)

    2017-01-15

    The interplay of such cornerstones of modern nonlinear fiber optics as a nonlinearity, stochasticity and polarization leads to variety of the noise induced instabilities including polarization attraction and escape phenomena harnessing of which is a key to unlocking the fiber optic systems specifications required in high resolution spectroscopy, metrology, biomedicine and telecommunications. Here, by using direct stochastic modeling, the mapping of interplay of the Raman scattering-based nonlinearity, the random birefringence of a fiber, and the pump-to-signal intensity noise transfer has been done in terms of the fiber Raman amplifier parameters, namely polarization mode dispersion, the relative intensity noise of the pump laser, fiber length, and the signal power. The obtained results reveal conditions for emergence of the random birefringence-induced resonance-like enhancement of the gain fluctuations (stochastic anti-resonance) accompanied by pulse broadening and rare events in the form of low power output signals having probability heavily deviated from the Gaussian distribution. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Small Molecule DFPM Derivative-Activated Plant Resistance Protein Signaling in Roots Is Unaffected by EDS1 Subcellular Targeting Signal and Chemical Genetic Isolation of victr R-Protein Mutants.

    Science.gov (United States)

    Kunz, Hans-Henning; Park, Jiyoung; Mevers, Emily; García, Ana V; Highhouse, Samantha; Gerwick, William H; Parker, Jane E; Schroeder, Julian I

    2016-01-01

    The small molecule DFPM ([5-(3,4-dichlorophenyl)furan-2-yl]-piperidine-1-ylmethanethione) was recently shown to trigger signal transduction via early effector-triggered immunity signaling genes including EDS1 and PAD4 in Arabidopsis thaliana accession Col-0. Chemical genetic analyses of A. thaliana natural variants identified the plant Resistance protein-like Toll/Interleukin1 Receptor (TIR)-Nucleotide Binding (NB)-Leucine-Rich Repeat (LRR) protein VICTR as required for DFPM-mediated root growth arrest. Here a chemical genetic screen for mutants which disrupt DFPM-mediated root growth arrest in the Col-0 accession identified new mutant alleles of the TIR-NB-LRR gene VICTR. One allele, victr-6, carries a Gly216-to-Asp mutation in the Walker A domain supporting an important function of the VICTR nucleotide binding domain in DFPM responses consistent with VICTR acting as a canonical Resistance protein. The essential nucleo-cytoplasmic regulator of TIR-NB-LRR-mediated effector-triggered immunity, EDS1, was reported to have both nuclear and cytoplasmic actions in pathogen resistance. DFPM was used to investigate the requirements for subcellular EDS1 localization in DFPM-mediated root growth arrest. EDS1-YFP fusions engineered to localize mainly in the cytoplasm or the nucleus by tagging with a nuclear export signal (NES) or a nuclear localization signal (NLS), respectively, were tested. We found that wild-type EDS1-YFP and both the NES and NLS-tagged EDS1 variants were induced by DFPM treatments and fully complemented eds1 mutant plants in root responses to DFPM, suggesting that enrichment of EDS1 in either compartment could confer DFPM-mediated root growth arrest. We further found that a light and O2-dependent modification of DFPM is necessary to mediate DFPM signaling in roots. Chemical analyses including Liquid Chromatography-Mass Spectrometry and High-Resolution Atmospheric Pressure Chemical Ionization Mass Spectrometry identified a DFPM modification product that is

  15. Sensitivity Enhancement of an Inductively Coupled Local Detector Using a HEMT-based Current Amplifier

    Science.gov (United States)

    Qian, Chunqi; Duan, Qi; Dodd, Steve; Koretsky, Alan; Murphy-Boesch, Joe

    2015-01-01

    Purpose To improve the signal transmission efficiency and sensitivity of a local detection coil that is weakly inductively coupled to a larger receive coil. Methods The resonant detection coil is connected in parallel with the gate of a HEMT transistor without impedance matching. When the drain of the transistor is capacitively shunted to ground, current amplification occurs in the resonator by feedback that transforms a capacitive impedance on the transistor’s source to a negative resistance on its gate. Results High resolution images were obtained from a mouse brain using a small, 11 mm diameter surface coil that was inductively coupled to a commercial, phased array chest coil. Although the power consumption of the amplifier was only 88 µW, 14 dB gain was obtained with excellent noise performance. Conclusion An integrated current amplifier based on a High Electron Mobility Transistor (HEMT) can enhance the sensitivity of inductively coupled local detectors when weakly coupled. This amplifier enables efficient signal transmission between customized user coils and commercial clinical coils, without the need for a specialized signal interface. PMID:26192998

  16. Heavily Tm3+-Doped Silicate Fiber for High-Gain Fiber Amplifiers

    Directory of Open Access Journals (Sweden)

    Yin-Wen Lee

    2013-12-01

    Full Text Available We report on investigation the potential of a 7 wt% (8.35 × 1020 Tm3+/cm3 doped silicate fibers for high-gain fiber amplifiers. Such a high ion concentration significantly reduces the required fiber length of high-power 2 μm fiber laser systems and allows the high-repetition rate operation in 2 μm mode-locked fiber lasers. To evaluate the feasibility of extracting high gain-per-unit-length from this gain medium, we measure several key material properties of the silicate fiber, including the absorption/emission cross-sections, upper-state lifetime, fiber background loss, and photodarkening resistance. We show through numerical simulations that a signal gain-per-unit-length of 3.78 dB/cm at 1950 nm can be achieved in a watt-level core-pumped Tm3+-doped silicate fiber amplifier. In addition, an 18-dB 2013-nm amplifier is demonstrated in a 50-cm 7 wt% Tm3+-doped double-clad silicate fiber. Finally, we experimentally confirm that the reported silicate host exhibits no observable photodarkening.

  17. Circuit models and experimental noise measurements of micropipette amplifiers for extracellular neural recordings from live animals.

    Science.gov (United States)

    Chen, Chang Hao; Pun, Sio Hang; Mak, Peng Un; Vai, Mang I; Klug, Achim; Lei, Tim C

    2014-01-01

    Glass micropipettes are widely used to record neural activity from single neurons or clusters of neurons extracellularly in live animals. However, to date, there has been no comprehensive study of noise in extracellular recordings with glass micropipettes. The purpose of this work was to assess various noise sources that affect extracellular recordings and to create model systems in which novel micropipette neural amplifier designs can be tested. An equivalent circuit of the glass micropipette and the noise model of this circuit, which accurately describe the various noise sources involved in extracellular recordings, have been developed. Measurement schemes using dead brain tissue as well as extracellular recordings from neurons in the inferior colliculus, an auditory brain nucleus of an anesthetized gerbil, were used to characterize noise performance and amplification efficacy of the proposed micropipette neural amplifier. According to our model, the major noise sources which influence the signal to noise ratio are the intrinsic noise of the neural amplifier and the thermal noise from distributed pipette resistance. These two types of noise were calculated and measured and were shown to be the dominating sources of background noise for in vivo experiments.

  18. Circuit Models and Experimental Noise Measurements of Micropipette Amplifiers for Extracellular Neural Recordings from Live Animals

    Directory of Open Access Journals (Sweden)

    Chang Hao Chen

    2014-01-01

    Full Text Available Glass micropipettes are widely used to record neural activity from single neurons or clusters of neurons extracellularly in live animals. However, to date, there has been no comprehensive study of noise in extracellular recordings with glass micropipettes. The purpose of this work was to assess various noise sources that affect extracellular recordings and to create model systems in which novel micropipette neural amplifier designs can be tested. An equivalent circuit of the glass micropipette and the noise model of this circuit, which accurately describe the various noise sources involved in extracellular recordings, have been developed. Measurement schemes using dead brain tissue as well as extracellular recordings from neurons in the inferior colliculus, an auditory brain nucleus of an anesthetized gerbil, were used to characterize noise performance and amplification efficacy of the proposed micropipette neural amplifier. According to our model, the major noise sources which influence the signal to noise ratio are the intrinsic noise of the neural amplifier and the thermal noise from distributed pipette resistance. These two types of noise were calculated and measured and were shown to be the dominating sources of background noise for in vivo experiments.

  19. Performance Optimization of a Low Noise Amplifier

    Science.gov (United States)

    Hatta, S. F. Wan Muhamad; Soin, N.

    2009-06-01

    This work presents potential performance optimization techniques that can be applied to an RF CMOS low noise amplifier (LNA). LNA noise optimization methods namely the Conjugate Noise Match (CNM), the Simultaneous Noise and Input Matching (SNIM), the Power Constrained Noise Optimization (PCNO) and the Power Constrained Simultaneous Noise and Input Matching (PCSNIM) are introduced and discussed. Through detailed analysis and review, it has been realized that the PCSNIM technique implies to be the best method in optimizing the noise performance of the LNA. The gain enhancement technique is another technique that is introduced in this work where positive feedback is employed to reduce the total conductance of the circuit and subsequently boosting the gain performance of the design. This work will also show how the amount of the gain enhancement technique is governed by stability considerations. Substrate biasing is additionally recommended to further boost the performance of the LNA so that the device employed can work more efficiently at low power voltage. To implement the forward body-biased NMOS scheme, a deep N-well process is needed, which can provide separate body region for the transistor. To demonstrate the above suggested optimization techniques, a fully-integrated narrow-band source degenerated cascode RF LNA that dissipates 19.89 mW from a 0.9 V power supply is designed and simulated using Cadence Virtuoso and Cadence's Analog Design Environment respectively, based on a 0.18 μm RF-CMOS process. The layout of the LNA is additionally presented at the end section of this paper.

  20. Class-E Amplifier Design Improvements for GSM Frequencies

    Directory of Open Access Journals (Sweden)

    Z. Nadir

    2011-06-01

    Full Text Available Efficient power amplifiers are essential in portable battery-operated systems such as mobile phones. Also, the power amplifier (PA is the most power-consuming building block in the transmitter of a portable system. This paper investigates how the efficiency of the power amplifier (which is beneficial for multiple applications in communcation sector can be improved by increasing the efficiency of switching mode class E power amplifiers for frequencies of 900 MHz and 1800 MHz. The paper tackles modeling, design improvements and verification through simulation for higher efficiencies. This is the continuation of previous work by the authors. These nonlinear power amplifiers can only amplify constant-envelope RF signals without introducing significant distortion. Mobile systems such as Advanced Mobile Phone System (AMPS and Global System for Mobile communications (GSM use modulation schemes which generate constant amplitude RF outputs in order to use efficient but nonlinear power amplifiers. Improvements in designs are suggested and higher efficiencies are achieved, to the tune of 67.1% (for 900 MHz and 67.0% (1800 MHz.

  1. Efficient performance simulation of class D amplifier output stages

    DEFF Research Database (Denmark)

    Nyboe, Flemming; Risbo, Lars; Andreani, Pietro

    2005-01-01

    Straightforward simulation of amplifier distortion involves transient simulation of operation on a sine wave input signal, and a subsequent FFT of the output voltage. This approach is very slow on class D amplifiers, since the switching behavior forces simulation time steps that are many orders...... of magnitude smaller than the duration of one period of an audio sine wave. This work presents a method of simulating the amplifier transfer characteristic using a minimum amount of simulation time, and then deriving THD from the results....

  2. FDML swept source at 1060 nm using a tapered amplifier

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Klein, Thomas; Wieser, Wolfgang

    2010-01-01

    We present a novel frequency-swept light source working at 1060nm that utilizes a tapered amplifier as gain medium. These devices feature significantly higher saturation power than conventional semiconductor optical amplifiers and can thus improve the limited output power of swept sources...... in this wavelength range. We demonstrate that a tapered amplifier can be integrated into a fiber-based swept source and allows for high-speed FDML operation. The developed light source operates at a sweep rate of 116kHz with an effective average output power in excess of 30mW. With a total sweep range of 70 nm...

  3. The Modulation Response of a Semiconductor Laser Amplifier

    DEFF Research Database (Denmark)

    Mørk, Jesper; Mecozzi, Antonio; Eisenstein, Gadi

    1999-01-01

    are analyzed. The nonlinear transparent waveguide, i.e. an amplifier saturated to the point where the stimulated emission balances the internal losses, is shown to be analytically solvable and is a convenient vehicle for gaining qualitative understanding of the dynamics of modulated semiconductor optical......We present a theoretical analysis of the modulation response of a semiconductor laser amplifier. We find a resonance behavior similar to the well-known relaxation oscillation resonance found in semiconductor lasers, but of a different physical origin. The role of the waveguide (scattering) loss...... amplifiers....

  4. Asymmetric gain-saturated spectrum in fiber optical parametric amplifiers

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Rottwitt, Karsten; Galili, Michael

    2012-01-01

    We demonstrate experimentally and numerically an unexpected spectral asymmetry in the saturated-gain spectrum of single-pump fiber optical parametric amplifiers. The interaction between higher-order four-wave mixing products and dispersive waves radiated as an effect of third-order dispersion...... influences the energy transfer to the signal, depending on its detuning with respect to the pump, and breaks the symmetry of the gain expected from phase-matching considerations in unsaturated amplifiers. The asymmetry feature of the saturated spectrum is shown to particularly depend on the dispersion...... characteristics of the amplifier and shows local maxima for specific dispersion values....

  5. MMIC DHBT Common-Base Amplifier for 172 GHz

    Science.gov (United States)

    Paidi, Vamsi; Griffith, Zack; Wei, Yun; Dahlstrom, Mttias; Urteaga, Miguel; Rodwell, Mark; Samoska, Lorene; Fung, King Man; Schlecht, Erich

    2006-01-01

    Figure 1 shows a single-stage monolithic microwave integrated circuit (MMIC) power amplifier in which the gain element is a double-heterojunction bipolar transistor (DHBT) connected in common-base configuration. This amplifier, which has been demonstrated to function well at a frequency of 172 GHz, is part of a continuing effort to develop compact, efficient amplifiers for scientific instrumentation, wide-band communication systems, and radar systems that will operate at frequencies up to and beyond 180 GHz. The transistor is fabricated from a layered structure formed by molecular beam epitaxy in the InP/InGaAs material system. A highly doped InGaAs base layer and a collector layer are fabricated from the layered structure in a triple mesa process. The transistor includes two separate emitter fingers, each having dimensions of 0.8 by 12 m. The common-base configuration was chosen for its high maximum stable gain in the frequency band of interest. The input-matching network is designed for high bandwidth. The output of the transistor is matched to a load line for maximum saturated output power under large-signal conditions, rather than being matched for maximum gain under small-signal conditions. In a test at a frequency of 172 GHz, the amplifier was found to generate an output power of 7.5 mW, with approximately 5 dB of large-signal gain (see Figure 2). Moreover, the amplifier exhibited a peak small-signal gain of 7 dB at a frequency of 176 GHz. This performance of this MMIC single-stage amplifier containing only a single transistor represents a significant advance in the state of the art, in that it rivals the 170-GHz performance of a prior MMIC three-stage, four-transistor amplifier. [The prior amplifier was reported in "MMIC HEMT Power Amplifier for 140 to 170 GHz" (NPO-30127), NASA Tech Briefs, Vol. 27, No. 11 (November 2003), page 49.] This amplifier is the first heterojunction- bipolar-transistor (HBT) amplifier built for medium power operation in this

  6. Introduction to RF power amplifier design and simulation

    CERN Document Server

    Eroglu, Abdullah

    2015-01-01

    Introduction to RF Power Amplifier Design and Simulation fills a gap in the existing literature by providing step-by-step guidance for the design of radio frequency (RF) power amplifiers, from analytical formulation to simulation, implementation, and measurement. Featuring numerous illustrations and examples of real-world engineering applications, this book:Gives an overview of intermodulation and elaborates on the difference between linear and nonlinear amplifiersDescribes the high-frequency model and transient characteristics of metal-oxide-semiconductor field-effect transistorsDetails activ

  7. Coherent combination of two Tm-doped fiber amplifiers.

    Science.gov (United States)

    Gaida, C; Kienel, M; Müller, M; Klenke, A; Gebhardt, M; Stutzki, F; Jauregui, C; Limpert, J; Tünnermann, A

    2015-05-15

    The efficient coherent combination of two ultrafast Tm-doped fiber amplifiers in the 2-μm wavelength region is demonstrated. The performance of the combined amplifiers is compared to the output characteristics of a single amplifier being limited by the onset of detrimental nonlinear effects. Nearly transform-limited pulses with 830-fs duration, 22-μJ pulse energy, and 25-MW peak power have been achieved with a combining efficiency greater than 90%. Based on this result, it can be expected that 2-μm-ultrafast-fiber-laser systems will enter new performance realms in the near future.

  8. High-speed CuBr brightness amplifier beam profile

    Science.gov (United States)

    Evtushenko, G. S.; Torgaev, S. N.; Trigub, M. V.; Shiyanov, D. V.; Evtushenko, T. G.; Kulagin, A. E.

    2017-01-01

    This paper addresses the experimental study of the beam profile of the CuBr brightness amplifier operating at a wide range of pulse repetition frequencies. The use of a medium-size gas discharge tube (2 cm) ensures the operation of the brightness amplifier both at typical PRFs (520 kHz) and at higher PRFs (up to 100 kHz), either with or without HBr additive. The effect of the active additive on the beam profile is demonstrated. The testing results on kinetic modeling of radial processes in the laser (brightness amplifier) plasma are also discussed.

  9. Efficiency Optimization in Class-D Audio Amplifiers

    DEFF Research Database (Denmark)

    Yamauchi, Akira; Knott, Arnold; Jørgensen, Ivan Harald Holger

    2015-01-01

    This paper presents a new power efficiency optimization routine for designing Class-D audio amplifiers. The proposed optimization procedure finds design parameters for the power stage and the output filter, and the optimum switching frequency such that the weighted power losses are minimized under...... the given constraints. The optimization routine is applied to minimize the power losses in a 130 W class-D audio amplifier based on consumer behavior investigations, where the amplifier operates at idle and low power levels most of the time. Experimental results demonstrate that the optimization method can...

  10. Rare-Earth Doped Photonic Crystal Fibre Lasers and Amplifiers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.

    2005-01-01

    In this thesis, a theoretical and numerical study of the use of rare-earthdoped photonic crystal fibres as optical amplifiers and lasers, has been performed. Photonic crystal fibres or microstructured optical fibres is a new kind of optical fibre in which the cladding region typically consist....... Their novel properties allow for design of optical fibre amplifiers and fibre lasers with superior performance, compared to solutions based on conventional fibres. The primary applications considered are high efficiency fibre amplifiers based on index guiding photonic crystal fibres, and cladding pumped...

  11. Digital laser mode amplification using ND: YAG amplifier

    CSIR Research Space (South Africa)

    Bell, Teboho

    2016-07-01

    Full Text Available amplification using Nd: YAG amplifier T. Bell1,2,* , & S. Ngcobo1 1CSIR-NLC, PO Box 395, Pretoria 0001, RSA. 2UKZN, Westville Private Bag X 54001, Durban 4000, RSA. *Email: tbell@csir.co.za ABSTRACT In this work we demonstrate the output power amplification... ranging from white to black, in 256 levels (8-bit encoding). . was used to measure the amplified LG beam power. RESULTS The seed intensity profiles of the input LGp,l modes are shown in Fig. 3(a). The amplified seed intensity profiles are also illustrated...

  12. Fiber optical parametric amplifiers in optical communication systems

    DEFF Research Database (Denmark)

    Marhic, Michel E.; Andrekson, Peter A.; Petropoulos, Periklis

    2015-01-01

    The prospects for using fiber optical parametric amplifiers (OPAs) in optical communication systems are reviewed. Phase-insensitive amplifiers (PIAs) and phase-sensitive amplifiers (PSAs) are considered. Low-penalty amplification at/or near 1 Tb/s has been achieved, for both wavelength- and time......-modulated signals. A PSA with 1.1-dB noise figure has been demonstrated, and preliminary wavelength-division multiplexing experiments have been performed with PSAs. 512Gb/s have been transmitted over 6,000km by periodic phase conjugation. Simulations indicate that PIAs could reach data rate x reach products...

  13. Minimizing Crosstalk in Self Oscillating Switch Mode Audio Power Amplifiers

    DEFF Research Database (Denmark)

    Knott, Arnold; Ploug, Rasmus Overgaard

    2012-01-01

    The varying switching frequencies of self oscillating switch mode audio amplifiers have been known to cause interchannel intermodulation disturbances in multi channel configurations. This crosstalk phenomenon has a negative impact on the audio performance. The goal of this paper is to present...... a method to minimize this phenomenon by improving the integrity of the various power distribution systems of the amplifier. The method is then applied to an amplifier built for this investigation. The results show that the crosstalk is suppressed with 30 dB, but is not entirely eliminated...

  14. Evaluation of commercial and experimental resist materials for use in MEBES mask making

    Science.gov (United States)

    Sauer, Charles A.; Dean, Robert L.; Morita, Etsuya; Tan, Zoilo C. H.; Smith, Bruce W.; Ewbank, Dale E.; Duttagupta, Sid P.; Rudack, Anne

    1995-12-01

    The SIA roadmap has identified CD control as a critical issue in mask making. PBS, the most popular resist used for electron-beam mask making in the U.S., may not perform at the level required for production of 250 nm devices. There is a need in the industry today for precise CD control and tight control of CD uniformity, as well as a desire to dry etch thin films on masks. These industry trends make the use of an alternative resist attractive. A project was initiated to determine if an acceptable substitute to PBS exists. A group of eleven negative and positive resists were examined. These included chemically amplified materials, two part- novolacs, and a silicon-containing resist, among others. The resists were evaluated by using design of experiments (DOE) methodology whenever possible. All masks were exposed on 10 kV MEBES writing tools. The results were tabulated and compared, using a SEMATECH criterion for acceptability. Results are presented, including optimization of some of the materials for sensitivity, process robustness, and dry etch capability. While none of the materials met all criteria, several resists performed at a level that make them candidates to replace PBS. Several options are presented that are of interest to the mask maker contemplating process changes to accommodate 250 nm and 180 nm technologies.

  15. Amplified fragment length polymorphism versus random amplified polymorphic DNA markers: clonal diversity in Saxifraga cernua.

    Science.gov (United States)

    Kjølner, S; Såstad, S M; Taberlet, P; Brochmann, C

    2004-01-01

    Random amplified polymorphic DNA (RAPD) markers are sensitive to changes in reaction conditions and may express polymorphisms of nongenetic origin. Taxa with variable chromosome numbers are particularly challenging cases, as differences in DNA content may also influence marker reproducibility. We addressed these problems by comparing RAPD and amplified fragment length polymorphism (AFLP) analyses of clonal identity and relationships in a chromosomally variable arctic plant, the polyploid Saxifraga cernua, which has been thought to be monoclonal over large geographical distances. Fifty-seven plants from four Greenland populations were analysed using a conservative scoring approach. In total, 26 AFLP and 32 RAPD multilocus phenotypes (putative clones) were identified, of which 21 were identical and each of the remaining five AFLP clones was split into two to three very similar RAPD clones. This minor difference can be explained by sampling error and stochastic variation. The pattern observed in Greenland corroborates our previous results from Svalbard, suggesting that rare sexual events in S. cernua are sufficient to maintain high levels of clonal diversity even at small spatial scales. We conclude that although AFLP analysis is superior in terms of efficiency, RAPDs may still be used as reliable markers in small low-tech laboratories.

  16. Control of residual carbon concentration in GaN high electron mobility transistor and realization of high-resistance GaN grown by metal-organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    He, X.G. [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Zhao, D.G., E-mail: dgzhao@red.semi.ac.cn [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Jiang, D.S.; Liu, Z.S.; Chen, P.; Le, L.C.; Yang, J.; Li, X.J. [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Zhang, S.M.; Zhu, J.J.; Wang, H.; Yang, H. [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215125 (China)

    2014-08-01

    GaN films were grown by metal-organic chemical vapor deposition (MOCVD) under various growth conditions. The influences of MOCVD growth parameters, i.e., growth pressure, ammonia (NH{sub 3}) flux, growth temperature, trimethyl-gallium flux and H{sub 2} flux, on residual carbon concentration ([C]) were systematically investigated. Secondary ion mass spectroscopy measurements show that [C] can be effectively modulated by growth conditions. Especially, it can increase by reducing growth pressure up to two orders of magnitude. High-resistance (HR) GaN epilayer with a resistivity over 1.0 × 10{sup 9} Ω·cm is achieved by reducing growth pressure. The mechanism of the formation of HR GaN epilayer is discussed. An Al{sub x}Ga{sub 1−x}N/GaN high electron mobility transistor structure with a HR GaN buffer layer and an additional low-carbon GaN channel layer is presented, exhibiting a high two dimensional electron gas mobility of 1815 cm{sup 2}/Vs. - Highlights: • Influence of MOCVD parameters on residual carbon concentration in GaN is studied. • GaN layer with a resistivity over 1 × 10{sup 9} Ω·cm is achieved by reducing growth pressure. • High electron mobility transistor (HEMT) structures were prepared. • Control of residual carbon content results in HEMT with high 2-D electron gas mobility.

  17. Design And Construction Of 300W Audio Power Amplifier For Classroom

    OpenAIRE

    Shune Lei Aung; Kyaw Soe Lwin and Hla Myo Tun

    2015-01-01

    Abstract This paper describes the design and construction of 300W audio power amplifier for classroom. In the construction of this amplifier microphone preamplifier tone preamplifier equalizer line amplifier output power amplifier and sound level indicator are included. The output power amplifier is designed as O.C.L system and constructed by using Class B among many types of amplifier classes. There are two types in O.C.L system quasi system and complementary system. Between them the comple...

  18. Quantum Dot Semiconductor Optical Amplifiers - Physics and Applications

    DEFF Research Database (Denmark)

    Berg, Tommy Winther

    2004-01-01

    This thesis describes the physics and applications of quantum dot semiconductor optical amplifiers based on numerical simulations. These devices possess a number of unique properties compared with other types of semiconductor amplifiers, which should allow enhanced performance of semiconductor...... and QW devices and to experiments on quantum dot amplifiers. These comparisons outline the qualitative differences between the different types of amplifiers. In all cases focus is put on the physical processes responsible the differences....... devices in communication systems in the future. The basic properties of quantum dot devices are investigated, especially regarding the potential of realizing amplification and signal processing without introducing pattern dependence. Also the gain recovery of a single short pulse is modeled...

  19. Characterisation of random DFB Raman laser amplifier for WDM transmission

    National Research Council Canada - National Science Library

    Rosa, Paweł; Rizzelli, Giuseppe; Tan, Mingming; Harper, Paul; Ania-Castañόn, Juan Diego

    2015-01-01

    We perform a full numerical characterisation of half-open cavity random DFB Raman fibre laser amplifier schemes for WDM transmission in terms of signal power variation, noise and nonlinear impairments...

  20. Amplifying mirrors with saturated gain without and with a resonator

    DEFF Research Database (Denmark)

    Skettrup, Torben

    2007-01-01

    An investigation of amplifying mirrors with a view to their use in resonator structures has been performed. Both non-saturated and saturated amplifying mirrors are demonstrated. It was found that relatively high values of gain (typical 5-10 times) can be obtained even when saturation is taken...... into account. Several resonator structures containing from two up to four mirrors, some including beamsplitters, are investigated. It was found that the gain to a first approximation depends only on the ratio between the pumping power and the input power on the amplifying mirror. It was also found...... that the configuration with four mirrors is well suited as an amplifier device working as an optical transistor since high values of gain up to 40 times could be obtained....

  1. On the unlimited gain of a nonlinear parametric amplifier

    DEFF Research Database (Denmark)

    Sorokin, Vladislav

    2014-01-01

    The present paper is concerned with analysis of the response of a nonlinear parametric amplifier in abroad range of system parameters, particularly beyond resonance. Such analysis is of particular interestfor micro- and nanosystems, since many small-scale parametric amplifiers exhibit a distinctly...... nonlinearbehavior when amplitude of their response is sufficiently large. The modified method of direct separa-tion of motions is employed to study the considered system. As the result it is obtained that steady-stateamplitude of the nonlinear parametric amplifier response can reach large values in the case...... of arbitrarilysmall amplitude of external excitation, so that the amplifier gain tends to infinity. Very large amplifiergain can be achieved in a broad range of system parameters, in particular when the amplitude of para-metric excitation is comparatively small. The obtained results clearly demonstrate that very...

  2. Systematic Design of EMI-Resilient Negative-Feedback Amplifiers

    NARCIS (Netherlands)

    Van der Horst, M.J.

    2012-01-01

    The information transfer capacity of negative-feedback amplifiers, and electronic circuits in general, is limited by three fundamental limitations being noise, bandwidth, and signal power. Electromagnetic Interference (EMI) is not a fundamental limitation, but it also hampers the information

  3. Hearing Aids and Personal Sound Amplifiers: Know the Difference

    Science.gov (United States)

    ... Products For Consumers Home For Consumers Consumer Updates Hearing Aids and Personal Sound Amplifiers: Know the Difference ... that FDA launched today. Signs of Loss of Hearing Mann says that consumers who suspect they suffer ...

  4. Fiber amplifiers under thermal loads leading to transverse mode instability

    DEFF Research Database (Denmark)

    Johansen, Mette Marie; Hansen, Kristian Rymann; Alkeskjold, Thomas Tanggaard

    2014-01-01

    Transverse mode instability (TMI) in rare-earth doped fiber amplifiers operating above an average power threshold is caused by intermodal stimulated thermal Rayleigh scattering due to quantum defect heating. We investigate thermally induced longitudinal waveguide perturbations causing power trans...

  5. Resistor-less charge sensitive amplifier for semiconductor detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pelczar, K., E-mail: krzysztof.pelczar@doctoral.uj.edu.pl; Panas, K.; Zuzel, G.

    2016-11-01

    A new concept of a Charge Sensitive Amplifier without a high-value resistor in the feedback loop is presented. Basic spectroscopic parameters of the amplifier coupled to a coaxial High Purity Germanium detector (HPGe) are discussed. The amplifier signal input is realized with an n-channel J-FET transistor. The feedback capacitor is discharged continuously by the second, forward biased n-channel J-FET, driven by an RC low–pass filter. Both the analog—with a standard spectroscopy amplifier and a multi-channel analyzer—and the digital—by applying a Flash Analog to Digital Converter—signal readouts were tested. The achieved resolution in the analog and the digital readouts was 0.17% and 0.21%, respectively, at the Full Width at Half Maximum of the registered {sup 60}Co 1332.5 keV gamma line.

  6. Mode selection for a key amplifier of a broadcast signal

    Science.gov (United States)

    Artym, A. D.; Asinovskii, A. L.; Bakhmutskii, A. E.

    1980-05-01

    The modulation characteristic and operation modes of a paraphase key amplifier with separate inductors are considered. Recommendations for selection of operation modes are given. Results of an experimental study are presented.

  7. 1.55 Micron High Peak Power Fiber Amplifier Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal, we propose to demonstrate and build a 1.55 micron single frequency high energy and high peak power fiber amplifier by developing an innovative...

  8. ZigBee Radio with External Low-Noise Amplifier

    Directory of Open Access Journals (Sweden)

    Allan HUYNH

    2010-03-01

    Full Text Available This article presents the performance study of a ZigBee module with an external low-noise amplifier, measured in both outdoor and indoor environments. Our previous study has already shown that the indoor campus environment such as walls and floors would reduce the radio link range drastically and the packet error rate increased. In this study, an external low-noise amplifier has been added to a ZigBee module to increase the receiver sensitivity. It is shown that with an external low-noise amplifier the outdoor radio range can reach up to 403 m with a negligible packet error rate compared to 144 m without the low-noise amplifier for point-to-point connection. Thus, by increasing the receiver sensitivity the radio range can be increased without increasing of the radio power output so that the power consumption can still be kept low to obtain long battery lifetime.

  9. Ultrafast optical signal processing using semiconductor quantum dot amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper

    2002-01-01

    The linear and nonlinear properties of quantum dot amplifiers are discussed on the basis of an extensive theoretical model. These devices show great potential for linear amplification as well as ultrafast signal processing.......The linear and nonlinear properties of quantum dot amplifiers are discussed on the basis of an extensive theoretical model. These devices show great potential for linear amplification as well as ultrafast signal processing....

  10. Design of low noise transimpedance amplifier for intravascular ultrasound

    KAUST Repository

    Reda, Dina

    2009-11-01

    In this paper, we study transimpedance amplifiers for capacitive sensing applications with a focus on Intravascular Ultra Sound (IVUS). We employ RF noise cancellation technique on capacitive feedback based transimpedance amplifiers. This technique eliminates the input-referred noise of TIAs completely and enhances the dynamic range of front-end electronics. Simulation results verify the proposed technique used in two different TIA topologies employing shunt-shunt feedback. ©2009 IEEE.

  11. Experimental research on mechanism of phase noise of laser amplifier

    Science.gov (United States)

    Liu, Lei; Liu, Yang; Zhang, Kun; Tang, Xiao-jun; Wang, Chao; Zhao, Hong

    2013-09-01

    Coherent combination of multiple laser amplifier is an important technique for high power and high beam quality laser. Laser amplifier uses master oscillator power amplifier (MOPA) configuration for narrow bandwidth and high beam quality laser. Then active phase control is used to make multiple laser amplifier phase synchronization for coherent spot in the far field. The center spot is N times brighter than the one of incoherent combination. At present, researchers have used this method to achieve 1.56kW coherent combination of nine fiber lasers and 105kW of seven slab lasers. The phase noise of the laser amplifier is an important factor affecting the coherent combination. There are two key technologies in the coherent combination. The one is fill factor of multiple laser spatial distribution, which determines main lobe energy of coherent spot. And the other is the phase noise of the laser amplifier, which decides stability of the coherent combination. The phase noise of laser amplifier is caused by many factors, mainly thermal disturbance and mechanical vibration. Due to the complexity of the phase noise generation, the research on phase noise is generally concentrated in the qualitative analysis. The phase noise is generally considered the time phase noise. It is phase dithering from variation refractive index by external disturbance. A variety of factors, such as temperature changes, mechanical vibrations, the pump power, affect phase noise. We establish an externally imposed discrete disturbance source on fiber laser amplifier and then analyze above-mentioned factors independently and quantitatively by the method. The experiments demonstrate space phase noise, dithering of beam direction, is simultaneously induced by either mechanical vibration or thermal disturbance. This experiment is significant for understanding mechanism of the phase noise and suppression of phase noise.

  12. Multiple-pass amplifiers for high-power laser systems

    Energy Technology Data Exchange (ETDEWEB)

    Jackel, S.; Givon, M.; Ludmirsky, A.; Eliezer, S.; Borowitz, J.L.; Arad, B.; Zigler, A.; Gazit, Y.

    1987-02-01

    Multiple-pass amplifiers were configured from Nd:glass rods using polarization and angular coupling techniques. Very high gain (>600) single beam triple-pass booster stages and high gain (30 or 15) single or double-beam double-pass amplifiers were combined to construct a very cost effective high-power (50 GW) pulsed laser system. These techniques were also effectively applied to smaller compact high repetition-rate systems.

  13. Use of a photonic crystal for optical amplifier gain control

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Shawn-Yu [Albuquerque, NM; Fleming, James G [Albuquerque, NM; El-Kady, Ihab [Albuquerque, NM

    2006-07-18

    An optical amplifier having a uniform gain profile uses a photonic crystal to tune the density-of-states of a gain medium so as to modify the light emission rate between atomic states. The density-of-states of the gain medium is tuned by selecting the size, shape, dielectric constant, and spacing of a plurality of microcavity defects in the photonic crystal. The optical amplifier is particularly useful for the regeneration of DWDM signals in long optical fibers.

  14. Femtosecond Amplifiers and Microlasers in the Deep Ultraviolet

    Science.gov (United States)

    2013-11-19

    the ultraviolet (UV) and visible regions of the spectrum, as well as their applications in photochemistry and medical therapeutics. We believe that...FEMTOSECOND AMPLIFIERS AND MICROLASERS IN DEEP ULTRAVIOLET J GARY EDEN UNIVERSITY OF ILLINOIS 11/19/2013 Final Report DISTRIBUTION A: Distribution...Performance Report 15/08/2010 - 14/08/2013 Femtosecond Amplifiers and Microlasers in the Deep Ultraviolet FA9550-10-1-0456 Eden, James Gary Professor

  15. Quantum Dot Semiconductor Optical Amplifiers - Physics and Applications

    OpenAIRE

    Berg, Tommy Winther; Mørk, Jesper

    2004-01-01

    This thesis describes the physics and applications of quantum dot semiconductor optical amplifiers based on numerical simulations. These devices possess a number of unique properties compared with other types of semiconductor amplifiers, which should allow enhanced performance of semiconductor devices in communication systems in the future. The basic properties of quantum dot devices are investigated, especially regarding the potential of realizing amplification and signal processing without ...

  16. High power diode laser Master Oscillator-Power Amplifier (MOPA)

    Science.gov (United States)

    Andrews, John R.; Mouroulis, P.; Wicks, G.

    1994-01-01

    High power multiple quantum well AlGaAs diode laser master oscillator - power amplifier (MOPA) systems were examined both experimentally and theoretically. For two pass operation, it was found that powers in excess of 0.3 W per 100 micrometers of facet length were achievable while maintaining diffraction-limited beam quality. Internal electrical-to-optical conversion efficiencies as high as 25 percent were observed at an internal amplifier gain of 9 dB. Theoretical modeling of multiple quantum well amplifiers was done using appropriate rate equations and a heuristic model of the carrier density dependent gain. The model gave a qualitative agreement with the experimental results. In addition, the model allowed exploration of a wider design space for the amplifiers. The model predicted that internal electrical-to-optical conversion efficiencies in excess of 50 percent should be achievable with careful system design. The model predicted that no global optimum design exists, but gain, efficiency, and optical confinement (coupling efficiency) can be mutually adjusted to meet a specific system requirement. A three quantum well, low optical confinement amplifier was fabricated using molecular beam epitaxial growth. Coherent beam combining of two high power amplifiers injected from a common master oscillator was also examined. Coherent beam combining with an efficiency of 93 percent resulted in a single beam having diffraction-limited characteristics. This beam combining efficiency is a world record result for such a system. Interferometric observations of the output of the amplifier indicated that spatial mode matching was a significant factor in the less than perfect beam combining. Finally, the system issues of arrays of amplifiers in a coherent beam combining system were investigated. Based upon experimentally observed parameters coherent beam combining could result in a megawatt-scale coherent beam with a 10 percent electrical-to-optical conversion efficiency.

  17. Thermally induced nonlinear mode coupling in high power fiber amplifiers

    DEFF Research Database (Denmark)

    Johansen, Mette Marie; Hansen, Kristian Rymann; Alkeskjold, Thomas T.

    2013-01-01

    Thermally induced nonlinear mode coupling leads to transverse mode instability (TMI) in high power fiber amplifiers. A numerical model including altering mode profiles from thermal effects and waveguide perturbations predicts a TMI threshold of ~200W.......Thermally induced nonlinear mode coupling leads to transverse mode instability (TMI) in high power fiber amplifiers. A numerical model including altering mode profiles from thermal effects and waveguide perturbations predicts a TMI threshold of ~200W....

  18. Distributed Mode Filtering Rod Fiber Amplifier With Improved Mode Stability

    DEFF Research Database (Denmark)

    Laurila, Marko; Alkeskjold, Thomas Tanggaard; Broeng, Jes

    2012-01-01

    We report 216W of average output power from a photonic crystal rod fiber amplifier. We demonstrate 44% power improvement before onset of the mode instability by operating the rod fiber in a leaky guiding regime.......We report 216W of average output power from a photonic crystal rod fiber amplifier. We demonstrate 44% power improvement before onset of the mode instability by operating the rod fiber in a leaky guiding regime....

  19. Ripple compensation for a class-D amplifier

    OpenAIRE

    Cox, Stephen M.; du Toit Mouton, Hendrik

    2015-01-01

    This paper presents the first detailed mathematical analysis of the ripple compensation technique for reducing audio distortion in a class-D amplifier with negative feedback. The amplifier converts a relatively low-frequency audio signal to a high-frequency train of rectangular pulses whose widths are slowly modulated according to the audio signal (pulse-width modulation, PWM). Distortion manifests itself through unwanted audio-frequency harmonics that arise in the output due to nonlinearitie...

  20. Ferrite bead effect on Class-D amplifier audio quality

    OpenAIRE

    Haddad, Kevin El; Mrad, Roberto; Morel, Florent; Pillonnet, Gael; Vollaire, Christian; Nagari, Angelo

    2014-01-01

    International audience; This paper studies the effect of ferrite beads on the audio quality of Class-D audio amplifiers. This latter is a switch-ing circuit which creates high frequency harmonics. Generally, a filter is used at the amplifier output for the sake of electro-magnetic compatibility (EMC). So often, in integrated solutions, this filter contains ferrite beads which are magnetic components and present nonlinear behavior. Time domain measurements and their equivalence in frequency do...